WO2007053051A1

WO2007053051A1 - Method of processing of a thermoplastic polymeric material, material by using a coated die

Info

Publication number: WO2007053051A1
Application number: PCT/RU2005/000541
Authority: WO
Inventors: Oleg Leonidovich Kulikov
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-03
Filing date: 2005-11-03
Publication date: 2007-05-10
Anticipated expiration: 2008-05-03

Abstract

A method of processing of thermoplastic polymeric material (thermoplast) in a fabrication equipment such as an extrusion die entails coating of the die wall by a layer of a viscoelastic substance such as a silanol or a polyol cured by a borate. A thermoplast may comprise a processing additive such as a silanol or a polyol in combination with a curing agent such as a borate or it may comprise a silanol or a polyol cured by a borate. A lubricant may comprise an anti-wear additive such a silanol cured by a borate. A reaction between the silanol and polyol with the curing agent may be effected in the presence of a catalyst such as a phosphate. Among improved parameters in polymer processing are reduced extrusion pressure and reduced or eliminated melt fracture. The anti-wear additives have improved water tolerance.

Description

METHOD FOR PROCESSING OF A THERMOPLASTIC POLYMERIC MATERIAL BY USING A COATED DIE

5 BACKGROUND OF THE INVENTION

1 FIELD OF INVENTION

The present invention relates generally to processing of thermoplastic polymeric material by extrusion, blow molding and injection molding More

10 particularly, the present invention provides a method of improving the melt processing of polyolefin resins The present invention relates partly to lubricating compositions comprising anti-wear and extreme pressure additives

2 PRIOR ART

Product Additives and Processing Additives

15 Processing of neat polymers by extrusion and molding is generally not possible Instead, it is common practice to "formulate" compositions containing a variety of ingredients in relatively small, but critical amounts These ingredients may be generally categorized into two classes, namely Product Additives and Processing Additives Illustrative of the Product Additives are the reinforcing and non-reinforcing

20 fillers, coupling agents, antiblocking agents, dispersion aids, plasticizers, light stabilizers and antioxidants The Processing Additives facilitate processing Foremost among these additives are lubricants, sometimes referred to as release agents, which prevent sticking of the thermoplastic polymer to fabrication surfaces such as extruder screws, extrusion dies, rolls, injection molds, and the like As an

25 exception from the rule some of the Product Additives simultaneously are Processing Additives, e g zinc stearate, which is a heat stabilizer as well as a lubricant

When a high molecular weight thermoplastic polymeric material based on polymers with narrow molecular weight distribution is extruded through a die, smooth

30 extrudates can only be obtained up to a certain output rate (ι e , shear rate, shear stress) Beyond that, surface irregularities begin to appear The irregularities such as surface roughness, known in the art as "melt fracture" or "sharkskin", limit the production rates in commercial applications. To achieve higher output rates, a Processing Additive is typically added to the thermoplastic resin prior to extrusion One of the primary functions of the Processing Additive is to delay, suppress, or eliminate the onset of surface flow defects such as sharkskin Certain fluoroelastomers (e g Viton A from DuPont, Dynamar from 3M,

Kynar from Atofina, etc.), see for example [S Hatzikinakos and K Migler Polymer Processing Instabilities Control and Understanding Marcel Dekker, 2005, vol 102 ISBN: 0 824 75386 0 hi], have been found to delay the onset of melt fracture and sharkskin defects so that higher output rates can be attained while still producing acceptable extrudates. Such additives are typically employed at a level of about 250 to 3,000 parts per million based on the weight of the thermoplastic polymeric material The main problem arising in the commercial use of these Processing Additives is a tendency for plate-out of decomposed substances on the extruder screw and/or the die lips (i e. die drool). The plate-out is often severe, requiring shut- down of the equipment and extensive clean-ups. In addition, fluorocarbon materials are inherently expensive.

Processing Additives based on silicone fluids have been effectively employed for many years to improve melt flow and release in plastics molding and extrusion, but their use can be complicated by the difficulty of adding the material on-line and a tendency for the low surface energy of the fluids to cause screw slip in some equipment designs. Dow Corning has designed its new series of additives as dry, solid pellets that can be blended at the press during molding or extrusion. Based on ultra high molecular weight siloxane gum (viscosity is about 15-20 Pas), these materials form dispersion within the polymer melt, controlling the mobility of the siloxane and virtually eliminating screw slip [http //www dowcoming com 121], The use of ultra high molecular weight siloxane gum shows improvement in melt flow at relatively high concentration of the additives what makes the method prohibitively expansive.

Another approach is described in [G N. Foster, et al Olefin polymer compositions containing silicone additives and the use thereof in the production of film material August 13, 1985, U S Pat No. 4,535,113 U S Class' 524/262 131] This invention discloses Processing Additives based on organo-modified silicones, which effectively reduce melt fracture. Unfortunately, the performance of these organo-modified silicone compounds is often greatly diminished in the presence of certain other thermoplastic additives such as zinc stearate, which commonly are used as mold release agents and as inhibitors for the discoloration of polyolefin products The use of block-copolymers based on siloxanes as Processing Additives to improve processing of elastomeric compositions is known from [M L DeLucia, et al. Method of thermally processing elastomeric compositions and elastomeric compositions with improved processability. U S Patent Application 200501 19410 A1 , June 2, 2005 U S. Class 525/100 /4/] Adding of a Processing Additive and Processing Adjuvant to thermoplastic organic was proposed in [P S. Leung, et al. US Patent No. 4,857,593. Process for processing thermoplastic polymeric material, August 15, 1989, U S. Class. 525/92B /5/]. According to the patent the Processing Additive is a polymeric material being thermodynamically not compatible with the thermoplastic polymeric material and having molecular weight from 500 to 100,000 and at least two monofunctional radicals on its molecule selected from hydroxy, alkoxy, epoxy, carboxy and amino radicals, while the Processing Adjuvant is based on material with a molecule having at least two monofunctional radicals wherein at least one functional radical provides preferential absorption over the Processing Additive for the fabrication surface and wherein at least one other functional radical is capable of bonding with the Processing Additive, wherein the Processing Additive and the Processing Adjuvant are present in the ratio from 50 1 to 1 20, preferably 5 1 to 1 5 and most preferably 2 1 to 1 :2. The examples of the Processing Additive are polyether polyols, silicone- polyether block copolymers, polyamines, polycarboxylic acids, polycarboxylic anhydrides and epoxy resins Examples of the Processing Adjuvant are organodenvatives of carboxylates, phosphates, thiophosphates, phosphonates, sulfates, phosphonic acids, carboxylic acids, sulfites, phosphorous acids, phosphoric acids, sulfuric acids, sulfonates, phosphates, thiophosphites and ammonia We consider this teaching as the closest to the proposed herein (a prototype) The use of hydroxyl-functional diorgano-modified silicones as Processing

Additives to a polyolefin resin is disclosed in [D Hauenstein, et al. Method of modifying polyolefin with diorganopolysiloxane process aid EP0722981 , C08L23/02 published JuI 24, 1996 /6/] Development of the method is disclosed in [Hauenstein, et al , Method for extruding thermoplastic resins, US Patent No 6,013,217 Dec 22, 1997 171] where the hydroxyl-functional diorgano-modified silicones are added into polyolefin resin in combination with an organo-phosphorous compound The resulting composition can be extruded at relatively high rates with little sharkskin formation Processing Additives for thermoplastic polymeric material which preferably consist of a combination of a silicone-glycol copolymer having carbinol- terminated grafts (ι e , having --COH end radical on the side chains) and a Phosphorous based Processing Adjuvant were disclosed by Leung et al in [P S Leung, et al , U S Pat No 4,925,890, Process for processing thermoplastic polymeric material, May 15, 1990, U S Class 524/133 /8/] High molecular weight siloxanes are extremely hydrophobic and having very low electrical conductivity Siloxane based fluids migrate to the product surface and their presence lowers pπntability and adhesion of the product to labels as well as it causes accumulation of static electrical charge at the product surface

The use of Processing Additives in combination with Processing Adjuvant is known also from [D E Priester, et al Processing aid system for polyolefins U S Patent No 5,707,569 January 13, 1998, U S Class 264/39 /9/] where the Processing Additive is a fluoropolymer and the Processing Adjuvant is selected from polyvinylacetate, ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ethylene/methacrylic acid copolymer, ethylene/vinyl alcohol copolymer, polyvinyl alcohol or ionomer In [M Fujiyama, H Inata, Melt Fracture Behavior of Polypropylene-Type Resins with Narrow Molecular Weight Distribution Il Suppression of Sharkskin by Addition of Adhesive Resins J Appl Pol Sc 84 (2002) 2120-2127 /10/] the sharkskin of the PP-type resins with narrow molecular weight distributions was suppressed by the use of the adhesive resins with good adhesion to metal in amount from about 3 to 5% The use of high molecular weight polyethylene glycol as Processing Additive is proposed in [T Tikuisis, et al High molecular weight polyethylene glycol as polymer process aids U S Patent Application 20050070644 A1 , March 31 , 2005 U S Current Class 524/1 15 /1 1/] The amount of polyethylene glycol used is preferably between 200 and 2,000 parts per million by weight (based on the weight of the polyolefin) It was disclosed in [O Kulikov and K Hornung, Process and Extrusion die for eliminating surface melt fracture during extrusion of thermoplastic polymeric material WO 2004/076151 A2 B29C 33/56 from 28 02 2003 /12/] that the use of an elastic coating at the extrusion die provides both partial slip and inhibition of sharkskin in processing of LLDPE by extrusion, see also [O. Kulikov and K Hornung, A simple way to suppress surface defects in the processing of polyethylene J. Non-Newtonian Fluid Mech. 124 (2004) 103-1 14 /13/] Novel Processing Additives based on thermoplastic polyurethane elastomers (TPUEs) were proposed recently in [Oleg Kulikov. Novel Processing Aids for Extrusion of Polyethylene J.Vinyl Addit Technol 1 1 (September 2005) 127-131 /14/], [O Kulikov, The use of dynamic rubber coatings to postpone the onset of melt fracture in processing of PE and PP resins, MP17, Section - Materials processing, Proc XIVth Int. Congr on Rheology August 22-27, 2004, Seoul, Korea /15/] and [O. Kulikov, K Hornung, M. Wagner, M Mueller, "Produktivitat rauf, Kosten runter. Neue Additive fϋr die Kunststoffverarbeitung", Plasverarbeiter, 4 (2005) 68-69 /16/]. TPUEs are characterized by strong hydrogen bonds between diisocyanates as well as physical bonding of the molecules due to phase separation of soft and hard segments of TPUEs

One disadvantage in the use of TPUEs as Processing Additives is a limited thermal stability of diisocyanates, which normally decompose at heating above 230 - 25O°C Another disadvantage that thermoplastic elastomers are thermodynamically compatible with many polymers having polar radicals Meanwhile there is a strong need for the use of Processing Additives in extrusion at elevated temperatures (above 23O°C) as well as for extrusion and injection molding of various elastomeric compositions, Polyurethanes, Polyamides, Polycarbonates, and Polysulphones

Silicone bouncing putty

The method to get a rubbery but yet plastic product by treatment of liquid polymeric dimethyl siloxane with boric oxide was first described in [R R McGregor and E L. Warrick, Treating Silicone Polymer with boric oxide, US Patent No 2,431 ,878, Dec 2, 1947 /17/] Bouncing putty based on organosiloxane-boron compound was described in [J G E Wright, Process for making a puttylike elastic- plastic siloxane derivative composition containing zinc hydroxide, US Patent No 2,541 ,851 , Feb 13, 1951 /18/] The process for making puttylike elastic-plastic siloxane derivative composition comprises heating a mixture comprising liquid polymeric dimethylsiloxane and from 5 to 25 per cent, by weight, based on the weight of the polymeric dimethylsiloxane, of a compound of boron selected from the group consisting of Pyroboric acid, boric anhydride, boric acid, borax, and hydrolyzed esters of boric acid, the said heating being continued until a solid, elastic product is obtained, adding a finely divided inorganic filler to the solid elastic product and 12 per cent, by weight, Zink hydroxide, based on the weight of the solid polymeric dimethylsiloxane, and kneading the compound until a puttylike, elastic- plastic product is obtained In according to [J G E Wright, Process for making puttylike elastic-plastic siloxane derivative composition containing zinc hydroxide US Patent No 2,541 ,851 , Feb 13, 1951 /18/] the process for making puttylike organo-silicon composition can be improved by the use of a catalyst, e g ferric chloride FCI₃ Properties of the product can be controlled by quantities of the boron compound, as well as hydrophilic and hydrophobic components of the mass Bouncing putty was renamed later to "Silly Putty™" because of its mam ingredient, Silicone The method for making puttylike elastic organo-silicon compositions, which retains its shape for an extended period of time and resist staining fabrics, is described in [B D Melvin and N Y Latham, Organosilicon Compositions, Oct 31 , 1967, US Patent No 3,350,344 /19/] which comprises (1 ) heating to a temperature between 4O°C to 25O°C in the presence of an effective amount of Lewis acid catalyst

Silly Putty demonstrates the richness and complexity of behavior that simple materials (often referred as the simplest material with visco-elasticity) can produce If rolled into a ball and dropped, the material bounces like rubber However, upon longer inspection the material is seen to sag under its own weight although the putty does not flow indefinitely on a flat surface It flows only above some threshold shear so it behaves like a plastic of Bingham In addition, if a shock or impulsive load is applied to the putty, it will shatter [http //www campoly com/notes/sillyputty pdf /20/] Silly Putty is known as a Dilatant Compound but in the range of load frequencies from 0 1 to 40 Hz it is closer to viscoelastic fluids or "Maxwell liquids" in their classical definition, see [W L Wilkinson, Non-Newtonian fluids, Pergamon Press, NY, 1960 /21/]. It is defined as an elastic-plastic silicone derivative composition in [James G E Wright, Process for making puttylike elastic-plastic siloxane derivative composition containing zinc hydroxide, US Patent No 2,541 ,851 , February 13, 1951 /18/] Viscosity of Silly Putty also depends on time of shearing and fluid undergoes a decrease in viscosity with time of kneading that is showing tixotropic behavior A viscoelastic material is one which possesses both elastic and viscous properties and its rheological behavior is much more complex in comparison to the dilatant material Viscoelastic materials could show either shear-thinning (drop of viscosity with an increase in shear rate) or shear-thickening (ι e. increasing viscosity with an increase in shear rate) Another well known viscoelastic substance having properties similar to the bouncing putty is a PVA Slime which could be made in reaction of Polyvinyl Alcohol (PVA) molecules with borax (sodium tetraborate)

Boundary or Extreme-pressure (E, P.) lubricants While under normal conditions termed "hydrodynamic", a film of lubricant is maintained between the relatively moving surfaces governed by lubricant parameters, and principally viscosity. However, when load is increased, clearance between the surfaces is reduced, or when speeds of moving surfaces are such that the film of oil cannot be maintained, the condition of "boundary lubrication" is reached, governed largely by the parameters of the contacting surfaces At still more severe conditions, significant destructive contact manifests itself in various forms such as wear and metal fatigue as measured by ridging and pitting It is the role of extreme-pressure (E. P.) additives to prevent this from happening For the most part, E. P agents have been oil soluble or easily dispersed as a stable dispersion in the oil, and largely have been organic compounds chemically reacted to contain sulfur, halogen (principally chlorine), Phosphorous, carboxyl, or carboxylate salt radicals, which react with the metal surface under boundary lubrication conditions. Stable dispersions of boric acids and hydrated metal borates have also been found to be effective as E P. agents.

The dispersions of boric acids and hydrated alkali metal borates are well known E P agents for such compositions, see following [Peeler, U. S Pat No 3,313,727, Alkali Metal Borate E P Lubricants Apr. 11 , 1967 /22/], [Adams, U S Pat No 3,912,643, Lubricant Containing Neutralized Alkali Metal Borates, Oct 14, 1975 /23/], [Sims, U S Pat. No. 3,819,521 , Lubricant Containing Dispersed Borate and a Polyol. Jun. 25, 1974 /24/], [Adams, U S. Pat No. 3,853,772, Lubricant Containing Alkali Metal Borate Dispersed with a Mixture of Dispersants. Dec. 10, 1974 /25/], [Adams, U S Pat. No. 3,997,454, Lubricant Containing Potassium Borate Dec 14, 1976 /26/], [Adams, U S Pat No 4,089,790, Synergistic Combinations of Hydrated Potassium Borate, Anti-wear Agents, and Organic Sulfide Antioxidants. May 16, 1978 /27/], [Adams, U.S. Pat No. 4,163,729, Synergistic Combinations of Hydrated Potassium Borate, Anti-wear Agents, and Organic Sulfide Antioxidants. Aug 7, 1979 /28/], [Frost, U. S Pat No. 4,263, 155, Lubricant Composition Containing an Alkali Metal Borate and Stabilizing Oil-Soluble acid. Apr 21 , 1981 /29/], [Frost, U. S Pat No. 4,401 ,580, Lubricant Composition Containing an Alkali Metal Borate and an Ester-Polyol Compound. Aug 30, 1983 /30/], [Frost, U. S Pat No 4,472,288, Lubricant Composition Containing an Alkali Metal Borate and an Oil-Soluble Amine Salt of a phosphorus Compound Sep 18, 1984 /31/], [Clark, U. S Pat No 4,584,873, Automotive Friction Reducing Composition. Aug 13, 1985 /32/], [Salentine, U.S Pat No 4,717,490, Synergistic Combination of Alkali Metal Borates, Sulfur Compounds, Phosphites and Neutralized Phosphate Jan 5, 1988 /33/]

The hydrated alkali metal borates used in the prior art as E P. agents have an empirical formula: XM₂O • B₂O₃ • yhbO wherein M is an alkali metal, preferably sodium or potassium, and x is a positive number from about 0 2 to 3. According to [Adams, U.S Pat No 3,912,643, Lubricant Containing Neutralized Alkali Metal Borates Oct 14, 1975 /34/], in the case x is from 0 75 to 3 the alkali metal borate is at least partly neutralized with an acidic anion of phosphoric or sulfuric acid. The quantity of the acid anion is used to bring the pH of an aqueous solution of the neutralized borate into the range from 6 to 8.

Combination of fillers with functionalized fluids or Processing Additives The use of talc, which is treated by functionalized siloxane, as an antiblock agent that adsorbs substantially reduced amount of Processing Additives in production of polyolefin film is known from [D K Drummond, Talc antiblock compositions and method of preparation U S. Patent No. 6,593,400 JuI 15, 2003 U S. Class: 523/205 /35/]. The use of a functionalized organo-siloxane or functionalized polyether in composition of filled polyolefins is known from [D Roberts, et al. Processing of coupled, filled polyolefins U. S Patent No 6,288,14. Sep 11 , 2001 , U S Class 523/217 /36/] and [D K. Drummond Process for the production of particular polymers. U. S Patent Application No 20040087682 A1 , May 6, 2004, U S Current Class: 523/205 /37/]. Combination of BN particles with fluorinated Processing Additives is known from [E. A Pruss, et al Polymer processing aid and method for processing polymers. Nov 4, 2004. U S. Patent Application No 20040220288 A1 U S Current Class: 521/50 /38/] BN powers are available commercially having high content of B₂O₃ (from about 0 5 to 5%) In opinion of the inventors high residual B₂O₃ content may enhance dispersion of the BN particles within the melt

3 OBJECTS OF THE INVENTION

It is a primary object of the present invention to provide a Processing Additive which enhances processibility of thermoplastic polymeric material especially at temperatures above 200°C The processing improvements, such as an inhibition of surface defects in the extrusion and/or molding of filled thermoplastics, a reduction in the pressure-to-fill during injection molding will be made apparent from the description and examples which follow Another object of the present invention is to increase of output rates and/or reduce the power consumption, operating pressure and fabrication temperature of the process without adversely affecting the physical properties of the fabricated product One other object of the present invention is to improve water tolerance of the anti-wear and E P additives for lubricating liquids

It was unexpectedly discovered that the viscoelastic substance based on compounds containing boron and oxygen can be used as a novel class of versatile Processing Additives. It was further unexpectedly discovered that performances of said Processing Additives can be improved by the use in composition of said viscoelastic substances of following chemicals- compounds containing alkali metals, compounds containing phosphorous and oxygen and compounds containing aluminum and oxygen The novel Processing Additives are broadly useful and superior to the conventional Processing Additives of the prior art for a variety of thermoplastic resin systems. It was also unexpectedly discovered that the viscoelastic substance based on siloxanes could be used a novel class of boundary lubricants or anti-wear and extreme pressure agents in lubricating oils and being superior to the prior art in water tolerance.

SUMMARY OF THE INVENTION

In accordance with the present invention a method of processing of molten thermoplastic polymeric material in fabrication equipment comprises that a layer of a viscoelastic substance cured by a compound containing boron and oxygen coats at least a portion of the rigid wall which is in a contact with said thermoplast.

In a particular embodiment of the present invention the viscoelastic substance is a product of the reaction of a curing agent based on a compound containing boron and oxygen with an additive polymeric substance reactive toward said curing agent

In a particular embodiment of the present invention the curing agent is selected from the group of chemical compounds consisting of boron oxide, boric acids, solvable in water salts of boric acids, esters of boric acids, amines of boric acids and mixtures thereof. In a particular embodiment of the present invention the additive polymeric substance is selected from the group of polymers bearing in their molecules at least two monofunctional radicals selected from the group consisting of hydrogen, halogen, hydroxyl, alkoxyl, carboxyl, oxime, epoxide, amine, or isocyanate.

In a particular embodiment of the present invention the additive polymeric substance is selected from the group of polymers bearing in their molecules at least two hydroxyl radicals

In a particular embodiment of the present invention the additive polymeric substance is selected from the group consisting of functionalized siloxanes, functionalized hydrocarbons, functionalized copolymers of hydrocarbons and siloxanes, functionalized fluoπnated polymers and mixtures thereof.

In a particular embodiment of the present invention the reaction between the curing agent and the additive polymeric substance is effected in the presence of a catalyst.

In a particular embodiment of the present invention the catalyst is selected from the group of chemical compounds consisting of phosphoric acids, polyphosphohc acids, phosphorus pentoxide, salts of alkali metals and phosphoric acids, salts of alkali metals and polyphosphoπc acids, salts of aluminum hydroxide and phosphoric acids, salts of ferric hydroxide and phosphoric acids, aluminum hydroxide and mixtures thereof and provided that an amount of said catalyst is selected from the condition that the ratio of the number of phosphorus atoms to the number of boron atoms is in the range from 0 01 to 1. In a particular embodiment of the present invention the viscoelastic substance contains inorganic fillers in an amount from 1 to 50 weight %

In a particular embodiment of the present invention the inorganic fillers are selected from the group of mineral powders with particles having plate-like structure consisting of mica, talc, natural and synthetic clay, hexagonal BN, and mixtures thereof

In a particular embodiment of the present invention the method comprises supply of the viscoelastic substance at least at a portion of the rigid wall of the fabrication equipment which is in a contact with the thermoplast

In a particular embodiment of the present invention the method comprises blending the thermoplast with the viscoelastic substance in an amount selected from the range from 0 001 to 10 parts, per hundred parts of the thermoplast, wherein said viscoelastic substance deposits at the rigid wall of fabrication equipment which is in a contact with said thermoplast.

In a particular embodiment of the present invention the method comprises simultaneous or separate in time blending the thermoplast with the curing agent based on the compound containing boron and oxygen and the additive polymeric substance reactive toward said curing agent, and provided that an amount of said components is selected from the range from 0 001 to 10 parts, per hundred parts of the thermoplast, wherein said components deposit and react at the rigid wall of fabrication equipment which is in a contact with said thermoplast.

In a particular embodiment of the present invention the composition of the viscoelastic substance is selected from the condition that elasticity of the viscoelastic substance is above to that of the thermoplastic polymeric material and said elasticity is measured at maximum temperature of processing and at frequency 10 Hz. In a particular embodiment of the present invention the method comprises extrusion of the thermoplastic polymeric material through a die wherein a layer of the viscoelastic substance having at least 40 nm thickness coats at least a portion of the die land area adjacent to the die exit and having length at least 10% from the die gap width

In accordance with the present invention a composition of a thermoplastic polymeric material comprises a main thermoplastic polymer and a processing additive in an amount selected from the range from 0 001 to 10 parts, per hundred parts of said thermoplast, wherein said thermoplast is a polyolefin resin and said processing additive is a viscoelastic product of the reaction of silanols with a curing agent based on a compound containing boron and oxygen

In a particular embodiment of the present invention the curing agent for the processing additive is selected from the group of chemical compounds consisting of boron oxide, boric acids, salts of boric acids and hydroxides of alkali metals, esters of boric acids, amines of boric acids and mixtures thereof and provided the condition that the ratio of the total number of alkali metal atoms to the total number of boron atoms is in the range from 0 1 to 1 In a particular embodiment of the present invention the curing agent for the processing additive additionally comprises a catalyst and said catalyst is selected from the group consisting of phosphoric acids, polyphosphoric acids, phosphorus pentoxide, salts of alkali metals and phosphoric acids, salts of alkali metals and polyphosphoric acids, salts of aluminum hydroxide and phosphoric acids, salts of ferric hydroxide and phosphoric acids, aluminum hydroxide and mixtures thereof and provided that the ratio of the total number of phosphorus atoms to the total number of boron atoms is in the range from 0 01 to 1

In accordance with the present invention a lubricating composition comprises an oil or grease of lubricating viscosity based on non-polar hydrocarbons and dispersed therein a minor amount of an anti-wear or extreme pressure agent wherein said agent is a product of the reaction of silanols with a curing agent based on a boron-oxygen containing compound

In a particular embodiment of the present invention the curing agent for the anti-wear agent is selected from the group of chemical compounds consisting of boron oxide, boric acids, salts of boric acids and hydroxides of alkali metals, esters of boric acids, amines of boric acids and mixtures thereof and provided a condition that the ratio of the total number of alkali metal atoms to the total number of boron atoms is in the range from O 1 to 1

In a particular embodiment of the present invention the curing agent for the anti-wear agent additionally comprises a catalyst and said catalyst is selected from the group consisting of phosphoric acids, polyphosphoπc acids, phosphorus pentoxide, salts of alkali metals and phosphoric acids, salts of alkali metals and polyphosphoπc acids and mixtures thereof and provided that an amount of said catalyst is selected from the condition that the ratio of the total number of phosphorus atoms to the total number of boron atoms is in the range from 0 01 to 1

DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

1 DEFINITION OF TERMS

Thermoplastic polymeric material

The terms "thermoplastic polymeric material", "thermoplastic material" or "termoplast" correspond to the substance based on organic polymers which can be plastically deformed at temperatures below a decomposition point The thermoplastic polymeric material generally useful in the present invention include the cross-linkable or vulcanizable elastomers, as long as they can be fabricated by standard thermoplastic melt processing techniques such as extrusion, milling, calendering, injection molding and/or melt spinning into fibers One important polymer group is the addition polymers including the polyolefins, fluorocarbon polymers, vinyls, styrenics, acrylics and methacrylics, diene elastomers, thermoplastic elastomers and polyacetals Another major group comprises the condensation polymers including the polyesters, polyamids, polycarbonates, polysulfones and polyurethanes Still another polymer group is the thermoplastic cellulosic ethers and esters

Most preferable are the olefin polymers, copolymers, terpolymers and the blends thereof Examples are interpolymers of olefin monomers such as ethylene, propylene, butene-1 , isobutylene, pentene-1 , hexene-1 , 4-methyl pentene-1 , octene- 1 , nonene-1 and decene-1 , interpolymers with dienes such as ethylidene norbornene, cyclopentadiene and hexadiene, interpolymers with polar monomers such as vinyl acetate, vinyl alcohol, acrylic acid and methacrylic acid, their esters and salts, acrylamide and methacrylamide and N-alkyl versions thereof, carbon monoxide and the like Examples of most preferable polyolefin homo and copolymer blends are the blends of one or more of LDPE (low density, high pressure polyethylene), HDPE (high density polyethylene), LLDPE (linear low density polyethylene), PP (isotactic polypropylene), EPR (ethylene/propylene rubber), EPDM (ethylene/propylene/diene monomer), EVA (ethylene/vinyl acetate), EEA (ethylene/ethyl acrylate) and EAA (ethylene/acrylic acid). The thermoplastic polymer may also be a blend of two or more of the above-mentioned homopolymers or interpolymers.

The above polymers and interpolymers are available in various types and grades and may be formulated with other ingredients into powders, pellets, flakes, granules, liquid resins or solutions They are well known in the art and further description thereof is considered unnecessary. These polymers are transformed into plastic articles by a variety of processes The present invention finds particular utility in extrusion and molding operations, and most preferably in film extrusion and injection molding.

Viscoelastic material and viscoelastic liquid

In solid mechanics, a material is elastic if it changes shape due to an applied load, but that when the load is removed, recovers its original shape A viscoelastic material is that one which possesses both elastic and viscous properties A viscoelastic fluid is a viscoelastic material capable to flow under applied load A gum is a sticky substance showing viscosity compatible with that of the thermoplastic polymeric material at processing temperature. Young's modulus G^* = G1 + ιG2 (also known as the modulus of elasticity or elastic modulus) is a measure of the stiffness of a given material. A tangent of losses tan ( alpha.) = G2/G1 that is the ratio of imaginary part of the Young's modulus G2 to its real part G1 is a measure of elasticity in solid mechanics The material is elastic if G2/G1 <1 and it is viscous if G2/G1 > 1. Visco-elasticity of polymeric melts indicates that the material acts as a viscous liquid over a long time period, but acts as an elastic solid over a short time period. In general, viscoelastic materials can demonstrate shear-thining that is drop in viscosity as shear rate increases or shear-thickening (dilatant behavior) that is increase in viscosity as shear rate increases Product Additives and Processing Additives

The definitions of Product Additives and Processing Additives are given in the overview of the Prior Art. Processing Additives are essentially not compatible thermodynamically with the thermoplastic polymeric material. Processing Additives are evaluated on pressure reduction and elimination of melt fracture. Antiblock agent - the material that roughen the surface of plastic films to reduce their tendency to stick together These materials may include synthetic silica, diatomaceous earth, and talc

Curing agent In accordance to [http. //www specιalchem4polymers com/resources/glossary

/39/] the term "cure" corresponds to a change in the properties of a polymeric system by a chemical reaction, which, for example, may be condensation, polymerization, vulcanization or addition, usually accompanied by the action of either heat or a catalyst or both, and with or without pressure A curing agent is a catalytic or reactive agent that brings the change when added to a resin. In [R. R McGregor and E L Warrick, Treating Silicone Polymer with boric oxide. US Patent No. 2,431 ,878, Dec.2, 1947 /17/] boron oxide has been found as an effective agent or a reagent, which turns low viscosity dimethylsilicone fluid to gummy-like products resembling natural rubber in their elasticity. For the purposes of the present invention we consider following compounds containing boron and oxygen as curing agents' boron oxide, boric acids, solvable in water salts of boric acids, esters of boric acids, boron amides and mixtures thereof

Boric acids

Boric acids refer to 3 compounds orthoboric acid (also called boracic acid, H₃BO₃ or B₂O₃ 3H₂O), metaboric acid (HBO₂ or B₂O₃ H₂O), and tetraboric acid (also called pyroboric, H₄B₄O₇ or 2(B₂O₃) H₂O) Orthoboric acid has a boiling point at 30O°C It dehydrates to form metaboric acid and tetraboric acid above 17O°C and 300°C respectively. Orthoboric acid is poorly soluble in cold water (4 - 5 g/100 ml at 2O°C) but dissolves readily in hot water, in alcohols and glycerol. Borate salts

Specific examples of the boric acid salts are alkaline metal salts, alkaline earth metal salts or ammonium salts of boric acid. More specific examples are sodium borates such as sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, and sodium octaborate, potassium borates such as potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, and potassium octaborate, calcium borates such as calcium metaborate, calcium diborate, tricalcium tetraborate, pentacalcium tetraborate, and calcium hexaborate, magnesium borates such as magnesium metaborate, magnesium diborate, trimagnesium tetraborate, pentamagnesium tetraborate, and magnesium hexaborate, and ammonium borates such as ammonium metaborate, ammonium tetraborate, ammonium pentaborate, and ammonium octaborate Economically attractive examples of the boric acid salts are sodium metaborate, NaBO₂, and sodium tetraborate, Na₂B₄O₇

Esters of boric acids

Orthoboric acid B(OH)₃ and boron oxide B₂O₃ on heating at 100 - 17O°C readily reacts with alcohols and phenols Alcohols can be polyhydric, e g. glycols and polyols. The boric acid esters include mono-, dι- and tπ-substituted organic esters of boric acid with alcohols and phenols Lower alcohols, e g , methanol, ethanol, propanol, butanol, octanol, diols (glycols), and polyols, i.e , those having less than about 10 Carbon atoms, are especially useful for preparing the boric acid esters for the purpose of this invention Specific examples are monomethylborate, dimethylborate, trimethylborate, monoethylborate, diethylborate, triethylborate, monopropylborate, dipropylborate, tripropylborate, monobutylborate, dibutylborate, and tributylborate [http //en.wikipedia org/wiki/Borates /40/] Examples of polyols useful in preparation of the boric acid esters are illustrated by ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, dibutylene glycol, tributylene glycol, and other alkylene glycols in which the alkylene radical contains from two to about 10 carbon atoms, Other useful polyhydric alcohols include glycerol, monooleate of glycerol, monostearate of glycerol, monomethyl ether of glycerol, pentaerythπtol, 9,10-dιhydroxy stearic acid, methyl ester of 9,10-dιhydroxy stearic acid, 1 ,2-butanedιol, 2,3-hexanediol, 2,4- hexanediol, pinacol, erythritol, arabitol, sorbitol, mannitol, 1 ,2-cyclohexanedιol, and xylene glycol. Catalysts

A catalyst is a substance that accelerates the rate of a chemical reaction without itself being transformed or consumed by the reaction The viscoelastic substance can be prepared in presence of a catalyst which is selected from the group including phosphoric acids, polyphosphoπc acids, phosphorus pentoxide, salts of alkali metals and phosphoric acids, salts of alkali metals and polyphosphoric acids, aluminum hydroxide, salts of phosphoric acid and aluminum hydroxide, salts of phosphoric acid and ferric hydroxide, hydrolysable salts of aluminum hydroxide or ferric hydroxide, selected from AICI₃, AI₂(SO₄)₃, AI(H₂PO₄), FeCI₃ Fine grounded or liquid catalyst can be mixed with the additive polymeric substance simultaneously or separate in time with the curing agent If it is used the catalyst comprises from 0 001 to 10 per cent by weight of the additive polymeric substance Most preferably an amount of said catalyst is selected from the condition that the ratio of the number of phosphorus atoms to the number of boron atoms is in the range from 0 01 to 1 After the reaction is finished the catalyst is trapped inside the viscoelastic additive polymeric material The same substance, e g AI(OH)₃, can be used both as a catalyst and filler and therefore it can comprise up to 60% of the thermoplastic organic polymer, preferably up to 20% The hydrolysable salts of aluminum and iron having catalytic activity can be prepared in situ when an appropriate amount of phosphoric acid or salts of the phosphoric acid and alkali bases is added to the vessel made of the steel or aluminum alloy The use of phosphoric acid or salts of the phosphoric acid and alkali bases as an additive has an advantage as this inorganic acid improves adhesion of the viscoelastic substance to the surface of fabrication equipment made of the steel or aluminum alloy Phosphoric acids and Phosphates

Specific examples of phosphoric acids and derivatives used are orthophosphoric acid, methaphosphoπc acid, phosphorus acid, polyphosphoric acids such as tripolyphosphoric acid, the polymetaphosphoπc acids, and the like, and compounds derived from the esterification thereof Phosphates are any salt, ester or anion of phosphoric acids Specific examples of the phosphoric acids salts are alkaline metal salts, alkaline earth metal salts or ammonium salts of phosphoric acids Functionalized hydrocarbon fluid or gum

Functional radical is, in organic chemistry, a group of atoms within a molecule that is responsible for certain properties of the molecule and reactions in which it takes part Organic compounds are frequently classified according to the functional radical or radicals they contain For example, methanol, ethanol, and isopropanol are all classified as alcohols since each contains a functional hydroxyl radical.

Functional radicals are attached to carbon backbone and give molecules different properties For the purposes of the present invention the functionalized hydrocarbon fluid or gum is selected showing viscosity measured at maximum temperature of processing and at 0 1 Hz shear rate below to that of thermoplastic polymeric material and having on their molecules at least two monofunctional radicals independently selected from the group consisting of hydrogen, halogen, hydroxyl, alkoxyl, carboxyl, oxime, epoxide, amine, isocyanate . It has been found that a broad range of functionalized hydrocarbon fluids and gums may be utilized in accordance with this invention. Suitable functionalized hydrocarbon fluids may come from the following classes of compounds glycols, macro glycols and polyols of aromatic, aliphatic, and combinations thereof, aromatic diamines and polyamines, alkanolamines and hydroxy acylamines, linear and branched polyol esters, polyol ethers, and caprolactone polyols, e g diols, triols, etc

The functionalized hydrocarbon based fluid or gum preferably contains at least two hydroxyl radicals in the molecule. The hydroxyl radicals may be located at the ends of the molecule, they may be distributed along the chain or they may be located both at the ends as well as along the chain Preferably, the hydroxyls reside at the molecular chain ends When the hydroxyls are located only along the chain, the terminal radicals may be any non-reactive moiety. Reaction products of boric acids or esters with functionalized hydrocarbon liquids are unstable to hydrolysis. Siloxanes have extreme hydrophobicity in comparison to the functionalized hydrocarbon fluids Therefore the use of the functionalized siloxane fluid or gum in composition of the Processing Additives is preferable Functionalized silicone (siloxane) fluid or gum

Siloxanes are a class of both organic and inorganic chemical compounds which consist entirely of silicon, oxygen, and the group selected from hydrogen, alkyl, haloalkyl, aryl, haloaryl, aralkyl, polyether, imino, epoxy or vinyl. Siloxanes are also known as "silicones" or "silicone elastomers". Siloxane based fluid or gum is a polymeric material with molecular weight ranging from 20 to 2,000,000 [http //www fluorochemsilanes co uk /41/] It can be linear or branched, low viscosity (from about 1 mPas to 100,000) or high viscosity (from 100,000 to 2,000,000 mPas). The functionalized siloxane based fluid or gum preferably contains at least two hydroxyl radicals in the molecule. The most common alkyl radicals include methyl, phenyl, and vinyl radicals and most preferably a methyl radical. A suitable siloxane based fluid or gum may be a linear or branched organo-modified silicone polymer or copolymer

For the purposes of the present invention the functionalized siloxane based fluid or gum is selected showing viscosity below to that of thermoplastic polymeric material at maximum temperature of processing and at 0 1 Hz shear rate and having on their molecules at least two hydroxyl radicals. The hydroxyl radicals may be located at the ends of the molecule, they may be distributed along the chain or they may be located both at the ends as well as along the chain Preferably, the hydroxyls reside at the molecular chain ends in the form of diorganohydroxysiloxy radicals, such as dimethylhydroxysiloxy, diphenylhydroxysiloxy, and methylphenylhydroxysiloxy, inter alia Chemical structure of these functional siloxane fluids is close to HO-R₂SιO-(R₂SiO)n-R₂Si-OH, where R is an alkyl radical Among all the polyorganosiloxanes, polydimethylsiloxanes have received the most attentions due to their unique properties, such as extremely low glass transition temperature (-123°C), very low surface energies (20-21 dynes/cm), hydrophobicity, good thermal and oxidative stability, high gas permeability, excellent atomic oxygen resistance, biocompatibility, low dielectric constant, and low solubility parameter and relatively low cost. Low viscosity siloxanes are soluble in acetone, ethanol, dioxane and dihexyladipate

When phenyl radicals replace the methyl radicals on silicon atoms, either in the form of methylphenylsiloxane or diphenylsiloxane, the glass transition temperature of the siloxane will increase, as well as the thermal and the oxidative stability, and organic solubility characteristics For polymethylphenyl siloxane the service temperature is up to 29O°C When the hydroxyls are located only along the chain, the terminal radicals of the diorgano-modified silicones may be any non- reactive moiety, typically a triorganosiloxy species such as trimethylsiloxy. Mixtures of two or more such polymers or copolymers may be employed as the siloxane based fluid or gum It is also preferred, although not critical, that during the processing of the thermoplastic polymeric material the siloxane based fluid or gum has a viscosity lower than that of the molten thermoplastic polymer. Most preferably the viscosity of the additive is at least ten times lower than that of the molten thermoplastic polymer during processing In general the following are representative materials that may be employed in the present invention as organo-modified silicones' silicone polyols (silanols), block copolymers based on silicone with polyester, polyether or polycaprolactone polyols and mixtures thereof. Under acidic or basic conditions the silanols can undergo a condensation reaction to form a siloxane bond with elimination of water This reaction can be employed to produce siloxane block copolymers and higher molecular weight siloxanes A condensation reaction (also known as a dehydration reaction) is a chemical reaction in which two molecules or moieties react with each other with the concurrent loss of by-product, e g. water or alcohol. To promote the condensation reaction polydiorganosiloxane fluids are heated in the presence of a catalyst (acid or base) Typically the reaction is carried out at a temperature of 5O°C to 200°C and at atmospheric pressure, preferably at temperature of 100°C to 150°C Suitable condensation reaction catalysts can be base catalysts including metal hydroxides such as potassium hydroxide and sodium hydroxide, metal salts such as silanolates, carboxylates, and carbonates, ammonia, amines, and titanates such as tetrabutyl titanates, and combinations thereof, see [U S. Pat No 4,639,489 to Aizawa et al., Jan 27, 1987 /42/]

Silicone resins As used herein, the term "resin" describes a silicone composition wherein the molecular structure is arranged in a predominantly three-dimensional network. Silicone resins are commercially available with molecular weight ranging from 2000 to 300,000 and having from 0 2 to 5% of silanol content

Inorganic fillers and Reinforcements

Fillers are relatively inert materials that are added to some plastics in amounts ranging from about 1 to 60 per cent to improve hardness, abrasion resistance, impact strength, solvent resistance and to modify electrical characteristics Some are added to plastic materials primarily to lower cost The most common fillers are fumed silica or hydrated silica, carbon black, calcium carbonate, calcium sulphate, talc, diatomaceous earth, silica, alumina, bentonite, clay, ferric oxide, zinc hydroxide, wood flour, metallic powders and combinations thereof In one embodiment BN powers having high content of B₂O₃ (from about 0 5 to 5%) can be used both as a curing agent and filler

Inorganic fillers having plate-like (layered) structure

Many clays are aluminosilicates, which have a sheet-like (layered) structure, and consist of silica SiO₄ tetrahedra bonded to alumina AlOε octahedra in a variety of ways A 2 1 ratio of the tetrahedra to the octahedra results in smectite clays, the most common of which is montmorillonite Other metals such as magnesium may replace the aluminium in the crystal structure Depending on the precise chemical composition of the clay, the sheets bear a charge on the surface and edges, this charge being balanced by counter-ions, which reside in part in the inter-layer spacing of the clay The thickness of the layers (platelets) is of the order of 1 nm and aspect ratios are high, typically 100-1500 The clay platelets are truly nanoparticulate The platelets are not totally rigid, but have a degree of flexibility The negatively charged surface of the clay can adsorb polar liquids (e g water) as well as various ions present

2 PREPARATION OF PROCESSING ADDITIVES

The general process of forming the viscoelastic substance of the invention comprises blending of the functionalised hydrocarbons, siloxanes, block copolymers of hydrocarbons and siloxanes, fluoπnated functionalised hydrocarbons and/or mixtures thereof with the curing agent and heating of the blend to temperature from about 7O°C to about 25O°C, preferably within the range from about 100°C to about 15O°C until an increase in viscosity is effected The viscoelastic substance made from functionalized hydrocarbons is unstable to hydrolysis Siloxanes are hydrophobic and the viscoelastic substance made from functionalized siloxanes is more stable for storage in wet atmosphere Therefore the use of functionalized siloxanes is advantageous when the viscoeiastic substance is supposed to contact moisture during long storage. Silanols that are functionalized siloxanes terminated with hydroxyl radicals are relatively cheap chemical products. Therefore the use of silanols is preferable. Without wishing to be bond by a theory presented below we give a tentative description of the process for the use of silanols as functionalized siloxanes Silanols react with boric acid resulting to monoesters H-O-(R₂SI-O)_N-H + B(OH)₃ -> (H-O)₂-B-O-(R₂SI-O)_N-B-(O-H)₂

For acidic siloxane mixtures the catalysts can be strong Brϊnsted acids like sulfuric acid, phosphoric and polyphosphoπc acid, Lewis acids (e g. AICI₃, FeCI₃), or combinations thereof Viscosity of the composition grows due to hydrogen bonding between the esters A noticeable change in viscosity happens if the number of boron atoms in a curing agent is above the number of hydroxyl radicals in silanols. Elasticity of the product is dropping when the ratio of the number of boron atoms to the number of hydroxyl radicals in silanols is much above 10 because an excessive amount of boron oxide is trapped as solid inclusions inside the product Hydrogen bonding between the esters is strong and prevents evaporation of the product at elevated temperatures Monoesters of orthoboric acid can be converted on further heating into monoester of metaboric acid with release of water: (H-O)₂-B-O-(R₂Si-O)N-B-(O-H)₂ -> (H-O)₂-B-O-(R₂SI-O)_N-B=O + H₂O

Under long exposure to temperatures above 15O°C the elastic-plastic product turns into a solid body showing low plasticity. The change in plasticity can be attributed to three-dimensional covalent bonding between boron atoms similar to structure of boron oxyde. This metamorphosis is reversible and in wet air at room temperature the solid product slowly recovers plasticity. Additives of alkali bases, hydrocarbon polyols, salts and esters of phosphoric in a minor amount can extend plastic properties of the product to higher temperatures. The alcohols and glycols having boiling point above processing temperature and that are chemically stable at heating can be used as additives to improve elasticity of the product made of functionilized siloxanes One such example is glycerol if the processing temperature is below 200°C

Under strong alkaline conditions the silanols can undergo a condensation reaction to form a siloxane bond with elimination of water and the product turns to a rubber-like material having no plasticity The catalytic activity for alkali metal hydroxides was reported as Li < Na < K < Rb < Cs [S J Clarson, J A. Semlyeπ, Siloxane Polymers, PTR Prentice Hall, New York (1993) /43/] Therefore the alkali metal borate has to be partly neutralized with an acidic anion of a phosphoric acid or sulfuric acid. The quantity of the acid anion is used to bring the pH of an aqueous solution of the neutralized borate into the range from 6 to 10 5. Preparation of the blend of Processing Additives with fillers

The filler having plate-like structure is preferably provided as a powder As used herein, powder means a mass of particles having a normal particle size less than about 0.1 mm, typically on the order of 0.1-100 microns, preferably less than 25 microns for the coarsest particles. "High aspect ratio" particles can be obtained by a wet milling process of inorganic minerals (e g aluminosilicates) having plate-like (layered) structure In this context, the term "aspect ratio" is the value determined by dividing particle diameter by particle thickness Preferably, the milling mixture includes milling media and a milling liquid Typically, the milling liquid comprises between about 70 and 95 wt % of the milling mixture The milling liquid may be water, methanol, ethanol, propanol, or butanol In one embodiment, the liquid is any one in which B₂O₃ is soluble, e g ethanol In another embodiment, the liquid is any one in which both E^C^ and an alkali base are soluble, e g water.

3 MECHANISM OF PROCESSING ADDITIVES Without wishing to be bound by a following description of the mechanism, we believe that the proposed processing aid works as follows The fabrication equipment is made in industry of a variety of materials By far the majority is constructed of metal dies, screws and tubes. Representative metals commonly employed are steel, including stainless and chrome plated, bronze, sintered bronze, brass, and nickel In addition, various non-metallic fabrication surfaces may be encountered such as glass, graphite, and the like The formation of a boundary layer of the viscoelastic additive polymeric material cured by compositions containing boron and oxygen between the molten thermoplastic polymer and the fabrication surface provides a number of advantages in polymer melt processing Said viscoelastic material is immiscible with thermoplastic polymeric material, it deposits at the fabrication surface and work as a processing aid Functionalized hydrocarbons are normally present in industrial grades of thermoplastic polymeric material, e g. as zinc or calcium stearate [E W Flick, Plastics Additives - An Industrial Guide (2nd Edition), Publisher William Andrew Publishmg/Noyes, 2001 , ISBN 0-8155-1313-5 /44/] or appear in the melt during processing at high temperature as a result of oxidation of the polymers. Therefore the use of a curing agent based on compositions containing boron and oxygen as an additive results in a layer of a viscoelastic substance at the fabrication surface as soon as the curing agent reacts with the functionalized fluids or gums which deposit at the same surface as the curing agent. It is preferred nevertheless to use additives of special functionalized hydrocarbons and/or siloxanes to produce the viscoelastic substance in situ at the walls of the fabrication surface or to use additives of the viscoelastic substance produced in reaction of the functionalized hydrocarbons and/or siloxanes with the curing agent

It is preferred to thoroughly disperse the viscoelastic substance or the reacting components that are the curing agent and additive polymeric material in a resin compatible thermodynamically with the main thermoplastic polymer to form a masterbatch. This masterbatch (or concentrate), which preferably contains from about 1 to 10, more preferably from 2.5 to 5, weight percent of the viscoelastic material, or a curing agent and additive polymeric material in proportion that reaction between the components results in the viscoelastic material The master batch may be granulated or pelletized, dry-blended with the matrix resin and this blend then extruded The use of this masterbatch technique results in a more uniform dispersion in the matrix resin. The resin used in the preparation of the masterbatch may be the same as, or different from, the main polyolefin resin Preferably, the two are of the same general type (e.g. polyethylene in the masterbatch and as the main component of the thermoplast).

The viscoelastic substance or the reacting components (that are the curing agent and additive polymeric material) can be supplied as a solution, emulsion or dispersion in a volatile fluid having boiling temperature below temperature of melting of the thermoplastic polymers, e g methanol, water The use of functionalized fluids having boiling temperature above maximum temperature of processing is advantageous to prevent foaming of the product by not totally reacted components It is possible to obtain a relatively uniform dispersion of the additives in the matrix by injecting of the low viscous liquid carrier with the additives along the feeding zone of a screw section of an extruder while polyolefin pellets are fed in through the hopper thereof The use of low viscous liquid as a liquid carrier will improve uniformity of the dispersion of the processing aid The vapors of the liquid carrier will leave the extruder between solid granules of the thermoplastic polymer Functionalized hydrocarbons and/or siloxanes and a curing agent can be supplied in the fabrication equipment simultaneously or separate in time so that they react in a feeding zone at the surface of polymer granules and at the surface of the fabrication equipment

The reacting components (that are the curing agent and additive polymeric material) can be selected having temperature of boiling below temperature of melting of the thermoplastic polymer Examples are trimethyl borate (trimethyl ester of boric acid - (CH₃O)₃B - temperature of boiling is about 68 - 69°C) and low molecular weight Siloxanes terminated with hydroxyl radicals The use of volatile reactants simplifies dispersion of the viscoelastic fluid as the reaction goes partly in a gaseous phase and the reaction products deposit at the surface of fabrication equipment and polymer granules in the feeding zone of a screw extruder The use of the volatile reactants may result in nano-composites, i e dispersion of nanometer size scale elastic particles in the polymer matrix and provide an additional benefit in improvement of toughness of brittle polymers The use of the volatile reactants may result in a stable dispersion of nanometer size scale elastic particles in the lubricating liquid and provide an additional benefit in improvement of anti-wear properties of the additives

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 presents plots of the viscosity and the elasticity parameter (G1/G2) vs load frequency for LL1201 Figure 2 presents characteristic curves, i e plots of the pressure vs extrusion rate for tubular dies 12 and 32 mm as well as for a sharp diaphragm (orifice) at 165°C Figure 3 presents characteristic curves for extrusion through the tubular die 6 32 mm coated by polyester AS2060 and by the polyester (91 5%) cured by boric acid (8 5%) Figure 4 presents characteristic curves for extrusion through the die coated by BDO (ι e 1 ,4-Butanedιol, 60%) or Glycerol (60%) cured by boric acid (40%) Figure 5 presents plots of the viscosity and the elasticity parameter (G1/G2) vs load frequency for DOW 3-0133 (99%) cured by boric acid (1 %) Figure 6 presents plots of the viscosity and the elasticity parameter (G1/G2) vs load frequency for DOW 4-2737 (88%) cured by boric acid (12%) Figure 7 presents plots of the viscosity measured at 0 1 Hz and the elasticity parameter (G1/G2) measured at 10 2 Hz of DOW 3-0133 cured by boric acid vs boric acid content Figure 8 presents plots of the viscosity measured at 0 1 Hz and the elasticity parameter (G1/G2) measured at 10 2 Hz of DOW 4-2737 cured by boric acid vs boric acid content Figure 9 presents characteristic curves for extrusion through the die coated by DOW 4-2737 (71 %) cured by boric acid (29%) as well as by DOW 3-0133 (99 6%) cured by boric acid (0 4%) Figure 10 presents characteristic curves for extrusion through the die coated by a blend DOW 3-0133 (91 %) and BDO (5%) cured by boric acid (4%) as well as by a blend DOW 4-2737 (64%) and DOW 3-0133 (7%) cured by boric acid (29%) Figure 11 presents characteristic curves for extrusion through the die coated by a blend of DOW 4-2737 (68%) with AI(OH)₃ (17%) and Glycerol (7%) cured by borax (8%) as well as by DOW Q1 -3563 (91%) cured by a blend of borax (6%) and phosphoric acid (3%), and by a blend of DOW 4-2737 (75 2%) and AI(OH)₃ (16%) cured by a blend of borax (8%) and sodium hydroxide (0 8%) Figure 12 presents plots of the viscosity measured at 0 1 Hz and the elasticity parameter (G1/G2) measured at 10 2 Hz of DOW Q1 -3563 (2 g) cured by a blend of borax (0 22 g) and phosphoric acid (varιed%) vs the ratio of the number of [phosphorus atoms to the number of boron atoms Figure 13 presents plots of the viscosity measured at 0 1 Hz and the elasticity parameter (G1/G2) measured at 10 2 Hz of DOW Q1-3563 (2 g) cured by a blend of boric acid (0 1 g) and phosphoric acid (vaπed%) vs the ratio of the number of phosphorus atoms to the number of boron atoms Figure 14 presents characteristic curves for extrusion through the die coated by SilRez cured by boric acid, by a blend of DOW 4-2737 (49%) and MQ Resin (50) cured by boric acid (1 %) as well as by a blend DOW 3-0133 (86%) and SiIGeI 612 (13%) cured by boric acid (1 %) Figure 15 presents characteristic curves for extrusion through the die coated by a blend of DOW 4-2737 (61 %), filler (Graphite or Talc 30%) cured by a blend of borax (7%) and phosphoric acid (2%) Figure 16 presents characteristic curves for extrusion through the die coated by a blend of DOW 4-2737 (70 3%), DOW 3-0133 (18%) and mica (8 8%) cured by boric acid (2 9%) as well as by a blend of DOW 4- 2737 (95 7%) and SiIGeI 612 (7 5%) cured by boric acid (2 9%) Figure 17 presents a chat of pressure vs time for the use of Porcessing Additives in portions (averaged concentration 2500 ppm) Figure 18 presents a chat of pressure vs time extrusion of LLDPE without additives after extrusion with the additives

EXAMPLES

Whereas the exact scope of the instant invention is set forth in the appended claims, the following specific examples illustrate certain aspects of the invention However, the examples are set forth for illustration only and are not to be construed as limitations on the present invention except as set forth in the appended claims All parts and percentages are given by weight unless otherwise specified

The experiments were carried out using commercially available LLDPE "LL1201 XV" from ExxonMobil Chemicals This material was selected for its clarity, and its overall low level of additives in its formulation It is characterized by density - 0 925 g/cm3, melting point - 123°C and melt index - 0 7

The following materials were employed in the examples as additive polymeric materials

1 ,4-Butanedιol from Lyondell Chemical Company, viscosity 71 5 mPa-s at 25°C Glycerol from Merck , viscosity at 2O°C 1500 mPa-s, 934 mPa-s at 25C

Baycoll AS2060 from Bayer is a slightly branched polyester polyol, equivalent hydroxyl content 1 73-1 91 %, viscosity 1000 mPa-s at 75°C Baycoll AD5027 from Bayer is a linear polyester diol, equivalent hydroxyl content 0 87%, viscosity 2800 mPa-s at 75°C ELASTOSIL RT K from Wacker Chemie is a pourable, condensation-curing two- component silicone rubber that vulcanizes at room temperature in presence of a tin catalyst (4% curing agent T40) It is recommended for mould making and as a flexible mould release agent Its viscosity at 23°C - 12 000 Pa-s. The raw silicone rubber was used here without the catalyst

MQ RESIN POWDER from Wacker Chemie is the co-hydrolysis product of tetraalkoxysilane (Q resin) and trimethylethoxysilane (M resin) The chemical structure of MQ Resin Powder is a three dimensional network of polysilicic acid units terminated with trimethylsilyl radicals A few ethoxy and hydroxy functional radicals are also present ^■ SILRES® 601 from Wacker Chemie is a Solid Silicone Resin for Powder

Coatings OH radical content is about 5% SilGel® 612 from Wacker Chemie is a pourable, addition-curing, two-component silicone rubber that cures at room temperature to a very soft, gel-like vulcanizate.

AK 100,000 from Wacker Chemie is a high molecular weight polydimethyl siloxane, viscosity 100,000 mPa-s

Q1-3563 Fluid from DOW CORNING - dimethyl siloxane, hydroxyl-terminated polymer, viscosity 75 mPa s

^• 4-2737 PA FLUID from DOW CORNING hydroxyl-terminated polymer, silanol (Si-OH) content 3 6-4 0%, viscosity 38-45 mPa s

^• 3-0133 POLYMER from DOW CORNING with silanol content: 1530 ppm, viscosity 2000 mPa s EXAMPLE 1

Mechanical properties of neat polyethylene

Rheotest RT-20 from HAAKE-Thermo was used to measure dynamic mechanical performances of the materials The dynamic Young modulus, G^*, at 165°C and the complex viscosity, eta ^* = G^*/f, where f is frequency of load, at temperatures of 165°C and 205°C were measured with 20 mm parallel plates at distance 1 mm Frequency sweeps between 0.06 Hz and 40 Hz were carried out at each temperature and at controlled stress 63 6 Pa The ratio G1/G2 of elastic modulus G1 to viscous modulus G2 is used here as a criterion to characterize elastic properties of polymers instead of a more common value of the ratio G2/G1 having meaning of losses tan ( alpha ). The use of G1/G2 ratio instead of the inversed value tan ( alpha ) is more convenient to present data of viscosity and elasticity at one plot Many molten polymers manifest viscous (G1/G2 < 1 , i e. fluid-like) behavior at low frequencies and elastic (G1/G2 > 1 , solid-like) behavior at high frequencies For the used polyethylene LL1201 XV complex viscosity measured at constant stress drops as frequency rises Complex viscosity and the ratio G1/G2 versus frequency are presented in Figure 1 for temperature 165°C Molten LLDPE shows shear thinning and its viscosity drops as frequency of load is increasing at fixed level of stress.

EXAMPLE 2 Extrusion with a clean die

A ram extruder from Loomis with a barrel of 60 200 mm (Dιameter*Length) and a hydraulically driven piston was used to extrude molten PE from a die The piston velocity was controlled from a computer Values of the pressure and of the piston position were digitized during extrusion and transmitted to the computer for records The die and extrudate were illuminated by a stroboscope and appearances were video recorded by a camcorder at 25 frames/sec The stroboscope was synchronized with the camcorder and the video records were triggered simultaneously with the data records to get precise correspondence between them

We use in our experiments extrusion rate (V or velocity) [mm/s] which is derived from the volumetric flow rate Q as follows V = 4 Q/(.pi.^«d²), where d is the diameter of a tubular die. First, we made extrusion trials with dies 6 32 mm from steel or glass Before extrusion the die was exposed to open flame and heated to 600°C to burn out any organic contamination Slow extrusion of molten LLDPE at velocity about 1 mm/s through the die was done during 30 min to establish an initial status Then about 350 g of LLDPE was extruded with a velocity ramp from 1 to 500 mm/s At low velocity the extrudate is not disturbed by any instability and characterized by smooth glossy surface. The extrudate surface was getting sharkskin appearance at velocity above 5 4 mm/s Above V = 90 mm/s periodic "stick-slip" transitions were observed resulting in bamboo-like appearance of the extrudate when smooth areas and areas of sharkskin appearance alternate. Frequency of "stick-slip" transitions and duration of the slippage phase grow as the extrusion rate increases At velocity above 450 mm/s the extrudate shows a wavy distortion that is so called "gross melt fracture" Roughness of the extrudate surface at velocity from 5 4 to 90 mm/s shows pronounced quasi-penodicity

The Flow Curve that is a plot of apparent shear stress versus apparent shear rate is commonly used for Theological characterization of plastics, see for example [W L. Wilkinson Non-Newtonian Fluids, Pergamon Press, London (1960) /45/] Meanwhile neither an apparent shear stress nor apparent shear rate is a parameter that governs sharkskin Therefore we present a characteristic curve as a curve of Pressure (P) in the die entrance area versus extrusion rate (or velocity V) to characterize flow in the tubular dies The apparent shear stress can be calculated as P/(4 L/d), where L is the die length while the apparent shear rate is given by 32 Q/( pi.^«d³) = 8 V/d. The characteristic curve of pressure versus velocity is presented in Figure 2 for steel dies having diameter 6 mm by a solid line for the length 32 mm, by a dashed line for length 12 mm and by a dotted line for a sharp diaphragm (orifice) The diaphragm was made from a steel disk (2 mm thickness) and having conical entrance with full angle 90° The onsets of sharkskin are marked at the curves by crosses in circles (7 4, 6 3, 4.7 mm/s)

EXAMPLE 3 Extrusion with the die coated by functionalized fluids

Following functionalized fluids were used to coat inner surface of the dies 6 32 mm or 6 28 mm from steel. Baycoll AS 2060, Baycoll AD 5027, ELASTOSIL RT K, DOW 3-0133 We used also a high molecular weight siloxane fluid AK 100,000 having no functional radicals reactive toward compositions containing boron and oxygen First, the die was heated in open flame to about 600°C to burn out any organic contamination. Then the die was filled by the fluids and attached to the extrusion press. Extrusion was done with a velocity ramp rising from 1 mm/s to the moment of intensive sharkskin appeared at the extrudate surface Onset of sharkskin was measured and presented in Table 1 for comparison Characteristic flow curve is presented in Figure 3 for the use of Baycoll AS 2060 (dashed line). An onset of sharkskin defects is shown by a cross at the curve (19 mm/s). Onsets of sharkskin defects for the dies coated by other functionalized fluids are presented also in Table 1 for comparison in the column marked as "without" a curing agent.

We have observed that with the use of high molecular weight fuctionalized fluids based on hydrocarbons or silanols the onset of sharkskin strongly depends on the die surface conditions Even after careful cleaning of the steel die from any pollution and producing an oxide layer at its surface the sharkskin defects appeared as narrow strips long before the defects appeared at the rest of the extrudate surface This behavior is quite different from the use of glass dies and especially of the die made from quartz glass Appearance of strips at the extrudate surface could be tentatively explained so that a steel die has not homogeneous surface and in some areas affiliation of functionalized fluids to its surface to is low, e g because the area has inclusions of graphite

We enriched the die surface by phosphorus in a following way The hot metal die was cooled down from about 500°C to room temperature by quick potting it into a beaker with water solution of phosphoric acid (about 1 % content) to remove an oxide layer The procedure was repeated a few times Then the die was heated up to about 300°C and cooled down slowly to room temperature The die was then coated by functionalized fluids and extrusion trials were made to detect the sharkskin onset We have observed a delay in the melt fracture onset from 95 to 124 mm/s when ELASTOSIL RT K from Wacker Chemie was used and from 70 to 153 mm/s when DOW 3-0133 was used to coat the die inside The use of phosphoric acid as a Processing Adjuvant is known from the prototype

EXAMPLE 4 Hydrocarbon functionalized fluids cured by boric acid

Boric acid as a curing agent was blended with Glycerol or with 1 ,4-Butanedιol and heated to temperature about 14O°C When an intensive foaming of the reacting materials at about 14O°C was finished the product was heated to about 19O°C for an hour

We used the viscoelastic substances to coat the die inside No change in the sharkskin onset was detected when we have used the product of reaction of boric acid with Glycerol in the weight ratio 2 1 Some delay of sharkskin was observed when the product was used with the ratio 2 3 of boric acid to Glycerol Narrow strips of sharkskin appeared at velocity about 8 5 mm/s The defects in these strips were growing in amplitude till velocity about 12 mm/s They disappeared at velocity above 29 5 mm/s to appear again at velocity about 47 5 mm/s Intensive melt fracture was detected at velocity above 79 mm/s Then 1 ,4-Butanedιol (BDO) cured by boric acid with was used With the ratio 2 3 of the boric acid to BDO some dullness appeared at the extrudate surface at velocity 9 7 mm/s and developed to sharkskin at 13 1 mm/s. Clean strips appeared at the extrudate surface at velocity 14 1 mm/s and sharkskin disappeared at velocity above 20 1 mm/s Narrow strips of sharkskin appeared again at velocity above 90 mm/s and developed into intensive melt fracture at velocity above 170 mm/s The characteristic curves in Figure 4 for the dies coated by Glycerol or BDO cured by boric acid didn't show a noticeable deviation from the reference curve (a clean die 6 32 mm) in the range of velocity from 1 to 90 mm/s. The onsets of sharkskin are marked at the curves by crosses and the data are presented for comparison in Table 1 in the column marked "w agent" that is "with a curing agent". EXAMPLE 5

Hydrocarbon functionalized fluids having filler cured by boric acid

Talk in powder (20%) was blended with polyester Baycoll AS2060 (71 4%) and the blend was heated to about 14O°C. Boric acid (5 2%) and borax (3 3%) as powder were added in small portions to the blend under stirring. When an intensive foaming of the reacting materials at about 14O°C was finished the product was heated to about 19O°C for an hour to remove water The viscoelastic substance was used to coat a steel die 6 32 mm inside Sharkskin defects were detected at about 63 mm/s as narrow strips. The value is presented in Table 1 for comparison.

EXAMPLE 6

Siloxanes cured by boric acid

A solution of tπ-ιsopropyl borate was prepared by stirring together 5 p b w. of boric acid and 95 p.b w. of isopropanol until dissolved The solution was added dropwise to DOW 4-2737 or DOW 3-0133, the blend was vigorously stirred, heated above 14O°C and cured at temperature 17O°C for about 24 hours Mechanical characteristics of the products were measured at 165°C Plots of viscosity and the ratio G1/G2 versus frequency are presented in Figure 5 for DOW 3-0133 with 1 % of boric acid and in Figure 6 for DOW 4-2737 with 12% of boric acid The measurements were made at temperature 165°C. Both compositions show shear- thinning behavior (viscosity drops as frequency of load at fixed stress is increasing) at frequencies above 1 Hz Plots of complex viscosity measured at 0 1 Hz and

G1/G2 at 10 2 Hz versus amount of boric acid in the reacting blend are presented in Figure 7 for DOW 3-0133 and in Figure 8 for DOW 4-2737 Sharp changes in elasticity and viscosity for the functionalized fluids based on siloxanes correspond to the molar ratio of boric acid to the content of Silanol functional radicals about 1 15

The viscoelastic substance produced from a blend of boric acid with DOW 4- 2737 in the ratio 2 3 was used to coat the die inside The characteristic curve is presented in Figure 9 by a dashed line The onset of sharkskin is marked at the curve by a cross (105 mm/s) We observed low lubrication at velocity below 6 mm/s There was lubrication in the range of velocities from 6 to 145 mm/s with maximum change in pressure 20% in comparison to the reference curve for a clean die At velocity about 5 5 mm/s some wavy dullness was present at the extrudate surface but it is disappeared at velocities above 7 mm/s Sharkskin defects appeared in narrow strips at velocity above 81 mm/s Stick-slip transitions were observed in range of velocities from 190 to 235 mm/s and super-flow in the range from 235 to 415 mm/s The extrudate was deformed by wavy distortions at velocity above 420 mm/s The viscoelastic substance produced from a blend of boric acid with DOW 3-

0133 (0 4% of boric acid) was prepared as it is described above With the use of the die coated by this viscoelastic substance strong lubrication (30 - 35% less pressure in comparison with a clean die) was observed in the velocity range from 1 to 200 mm/s Some dullness is appeared at the extrudate surface at velocity above 140 mm/s but intensive surface fracture is detected above 200 mm/s The characteristic curve is presented in Figure 9 by a dotted line The onset of melt fracture is marked at the curve by a cross (169 mm/s) Nor stick-slip transitions neither super-flow was observed in the range of velocities from 200 to 420 mm/s

The viscoelastic substance that is based on a blend DOW 4-2737 (64%) and DOW 3-0133 (7%) cured by boric acid (29%) was prepared as it is described above The characteristic curve is presented in Figure 10 by a dashed line With the use of the die coated by this material strong lubrication was observed at velocity from 1 to 5 mm/s in comparison with a clean die (a reference) Then at 8 mm/s the characteristic curve suddenly deviated to the reference one Above 8 mm/s lubrication was improved again and in range from 10 to 195 mm/s has shown even better lubrication than with the use of DOW 4-2737 and 0 4% of boric acid In the range of velocity from 5 7 to 9 9 mm/s some wavy dullness was present at the extrudate surface but it is disappeared at velocities above 10 mm/s Some dullness appeared at the extrudate surface at velocity above 140 mm/s but surface fracture onset was at 209 mm/s as stochastic surface rupture Nor stick-slip transitions neither super-flow extrusion was observed in the range of velocities from 200 to 420 mm/s The onsets of the sharkskin are presented in Table 1 for comparison.

EXAMPLE 7 Blend of functionalized fluids (siloxane and BDO) cured by boric acid

We used the viscoelastic substance made from a blend of DOW 3-0133 (91 %) and BDO (5%) cured by boric acid (4%). A characteristic flow curve is presented in Figure 10 by a dashed line In the range of the product velocity from 8 to 17 mm/s we detected narrow strips of sharkskin defects but the defects disappeared at velocity above 18 mm/s The surface defects appeared again at velocity above 123 mm/s as irregular craters in strips Super-flow extrusion was observed at velocity above 150 mm/s. EXAMPLE 8

Siloxanes cured by alkali-metal borates

Siloxane fluid DOW 4-2737 (68%) was blended with powder of borax (8%), aluminum hydroxide (17%) and glycerol (7%). The blend was cured by heating to 14O°C during 3 hours and 12 hours at temperature 95°C The die was coated inside by this viscoelastic substance and extrusion was done as it is described above Characteristic curve is presented in Figure 11 by a dashed line The onset of sharkskin was detected at about 108 mm/s

A solution of tri-methyl borate was prepared by stirring together 10 p b w. of boric acid and 90 p b w of methanol until dissolved. A solution of sodium hydroxide was prepared by stirring together 4.7 p.b w of sodium hydroxide and 95.3 p b.w of methanol until dissolved The solution of the tπ-methyl borate was added dropwise to DOW Q1-3563, the blend was vigorously stirred to produce emulsion and then the solution of the sodium hydroxide was added dropwise The blend was stirred, heated to about 14O°C, till an increase in viscosity is effected and then cured at temperature 95°C This viscoelastic substance was used to coat the die inside and extrusion was done as it is described above. Characteristic flow curve is presented in Figure 1 1 by a dash-dotted line The onset of sharkskin was detected at about 126 mm/s In the presence of alkali-metal hydroxides the silanols undergo a condensation reaction to form a siloxane bond with the elimination of water and result in the product of higher elasticity Reaction between the boric acid and siloxane fluid is slow when the ratio of the number of alkali-metal atoms to the number of boron atoms is above to 0 5 Aluminum hydroxide as well as salts of aluminum hydroxide and phosphoric acid, salts of aluminum hydroxide and sulfuric acid, salts of aluminum hydroxide and hydrochloric acid, and mixtures thereof can be used as a catalyst as they absorb some amount of alkali-metal ions When the ratio of the number of alkali-metal atoms to the number of boron atoms is above to 1 the reaction rate of boron oxide with silocanes is too slow in comparison to the rate of the condensation reaction even in presence of the catalyst and the product converts to a rubber-like solid having no plasticity.

EXAMPLE 9 Siloxanes cured by borax and phosphoric acid A solution of phosphoric acid was prepared by stirring together 5 p.b w of an ortho-phosphoric acid and 95 p b w of methanol until dissolved The reaction between functionalized siloxanes and borates in presence of alkali-metal ions accelerates when the alkali-metal ions are partly neutralized by an acid, preferably by a phosphoric acid Siloxane fluid Q1-3563 (2 g) was blended with the solution of phosphoric acid and heated under stirring to about 15O°C The blend was foaming and its viscosity was increasing Borax in powder (0 22 g) was added then, the blend was mixed and heated again After the reaction was finished the product was arranged for 12 hours in a drying shelf at 95°C. Amount of phosphoric acid was varied. Plots of viscosity measured at 0 1 Hz and of elasticity (G1/G2) measured at 10 2 Hz vs. the ratio of the number of phosphorus atoms to the number of boron atoms are presented in Figure 12 The reaction rate is too slow when the ratio of the number of phosphoric atoms to the number of boron atoms is below 0.01. The product has low elasticity when the ratio of the number of alkali-metal atoms to the number of boron atoms borax is above 1 EXAMPLE 10

Siloxanes cured by a blend of boric and phosphoric acids

Siloxane fluid Q1-3563 (2 g) was blended with the solution of phosphoric acid and heated under stirring to about 150°C. The blend was foaming and its viscosity was increasing When blended with the phosphoric acid and heated to about 140°C the low molecular weight siloxane fluid turns into a viscous liquid but hydrogen bonding is weak and both the acid and siloxanes evaporate when heated above 155°C. A solution of tri-methyl borate was added (0 1 1 g of Boric acid) the blend was mixed and heated again. After viscosity increased the product was cured in a drying chamber at 95°C for 12 hours. Amounts of phosphoric acid in the products were varied Plots of viscosity measured at 0 1 Hz and of elasticity (G1/G2) measured at 10 2 Hz vs the ratio of the number of phosphorus atoms to the number of boron atoms are presented in Figure 13. There is no noticeable impact of the catalyst when the ratio of the number of phosphoric atoms to the number of boron atoms is below 0 01 The product has too low viscosity when the ratio of the number of phosphorus atoms to the number of boron atoms is above 1

EXAMPLE 11 Siloxanes cured by a blend of boric acid and sodium orthophosphate

Powder of sodium orthophosphate hydrate (Na₃PO₄ ^*! 2H₂O) was added slowly to the Dow Q1-3563 (2 g) at about 14O°C under stirring till solved Then the solution of the tri-methyl borate (0 1 g of boric acid) was added under stirring at about 14O°C Amounts of sodium orthophosphate in the products were varied. The blends were cured at temperature 95°C Properties of the products are presented in Table 2 The products show too low elasticity when the ratio of the number of phosphorus atoms to the number of boron atoms is above 1

EXAMPLE 12 Siloxanes cured by a blend of borax and sodium orthophosphate Powder of sodium orthophosphate hydrate (Na₃PO₄ ^*12H₂O) was added slowly to the Dow Q 1-3563 (2 g) under stirring at about 140°C till solved Then borax in powder (0.22 g) was added under stirring at about 140°C Amounts of sodium orthophosphate in the products were varied The blends were cured at temperature 95°C Properties of the products are presented in Table 3 The products show too low plasticity when the ratio of the number of sodium atoms to the number of boron atoms is above 1 The products show too low viscosity when the ratio of the number of phosphorus atoms to the number of boron atoms is above 1. EXAMPLE 13 Blends od siloxanes with resins or rubbers cured by boric acid

The viscoelastic substance produced from blends of silicone resin SilRez with boric acid was used to coat the die inside. The characteristic curve is presented in Figure 14 by a dashed line The onset of sharkskin is marked at the curve by a cross (25 mm/s) We observed low lubrication at velocity below 150 mm/s The viscoelastic substance produced from blends of siloxane fluid DOW 4-2737 (49%), silicone MQ Resin (50%) with boric acid (1 %) was used to coat the die inside The characteristic curve is presented in Figure 14 by a dotted line. The onset of sharkskin is marked at the curve by a cross (25 mm/s) The viscoelastic substance produced from blends of siloxane fluid DOW 4-2737 (86%), silicone rubber SiIGeI 612 (13%) with boric acid (1%) was used to coat the die inside. The characteristic curve is presented in Figure 14 by a dash-dotted line The onset of sharkskin is marked at the curve by a cross (153 mm/s) and presented for comparison in Table 1 (No 14) in the column marked "w agent" that is "with a curing agent" The use of elastic composition results in better lubrication and further delay of the melt fracture onset The onsets of sharkskin are marked at the curves by crosses in circles

EXAMPLE 14 Siloxanes with inorganic fillers cured by borates Powder of inorganic fillers was added slowly to the blend of the DOW 4-2737

PA FLUID (80%) and DOW 3-0133 POLYMER (20%) Then the solution of the tri- methyl borate was added under stirring at about 14O°C. The blend was cured at temperature 95°C Following inorganic fillers were used' kaolin, bentonite, mica, BN, silica, aluminum hydrate, kaolin calcinated at 600°C, kaolin treated by a solution of PPDI in toluene (p-phenylene dnsocynate, 17% weight ratio to Kaolin), borax All products are stable to hydration resinous solids at room temperature

Borax was used in some experiments instead of the solution of the tri-methyl borate Powder of borax and inorganic fillers was added slowly to the blend of the DOW 4-2737 (80%) and DOW 3-0133 (20%). Then the product was heated to about 14O°C and cured at temperature 95°C. Following inorganic fillers were used aluminum hydrate, kaolin, bentonite, mica, BN, silica, fumed silica Only products made with aluminum hydrate are stable to hydration resinous solids at room temperature while others turn to viscous liquids after a week of storage in open air

The viscoelastic substance based on compositions containing Borax (9 3%) and DOW 4-2737 (56.3%), phosphoric acid (2.6%), BDO (2 8%), and Graphite (29%) was prepared as it is described above With the use of the die coated by the viscoelastic substance no lubrication was observed in velocity range from 1 to 8 mm/s. The characteristic curve is presented in Figure 15 by a dashed line. The onset of sharkskin is marked at the curve by a cross (63 mm/s) Macroscopic slip was detected above 233 mm/s

The viscoelastic substance based on compositions containing Borax (6 1 %), DOW 4-2737 (61.1 %), phosphoric acid (1.8%), and Talk (30 6%) was prepared as it is described above. With the use of the die coated by the elastic viscoelastic substance no lubrication was observed in velocity range from 1 to 8 mm/s The characteristic curve is presented in Figure 15 by a dotted line The onset of sharkskin is marked at the curve by a cross (110 mm/s) Macroscopic slip was detected above 222 mm/s It is interesting to note that the use of Graphite as a filler shows better lubrication in comparison to the use of Talc as a filler but it is less efficient to delay melt fracture onset.

The viscoelastic substance based on compositions containing boric acid (2 9%), DOW 3-0133 (18.0%), DOW 4-2737 (70 3%), and mica (8.8%) was prepared as it is described above The characteristic curve is presented in Figure 14 by a dashed line The onset of sharkskin is marked at the curve by a cross (198 mm/s)

The viscoelastic substance based on compositions containing boric acid (3 2%), DOW 4-2737 (75.7%), silicone rubber SiIGeI 612 (7.5%), and mica (13.6%) was prepared as it is described above With the use of the die coated by the elastic viscoelastic substance much better lubrication was observed in the range from 1 to 8 mm/s in comparison to the use of the composition having no rubber additives The characteristic curve is presented in Figure 14 by a dotted line The onset of sharkskin is marked at the curve by a cross (124 mm/s)

The onsets of melt fracture with the use of die coated by viscoelastic substances having fillers are presented in Table 4 for comparison The use of plate- like fillers like kaolin, BN and mica results in further delay of the melt fracture onset The use of silica as a filler also results in higher efficiency of Processing Additives. EXAMPLE 15 Blending boric acid with LLDPE to suppress sharkskin

Boric acid was used as a curing agent and blended with LLDPE in a following way It was dissolved in isopropanole to 5% concentration 8 4 g of the solution having about 0 42 g of boric acid was poured into a plastic bag with 1 kg of LLDPE granules. The content of the bag was thoroughly mixed and the solution was dried off by a jet of compressed air Content of the plastic bag was loaded into an extruder barrel, heated and molten there Induction time to suppress sharkskin was measured at V about 50 mm/s with the use of the die 3 35 22 mm from quartz glass. The die was heated by open flame to about 600°C just before an extrusion trial to burn out any organic contamination. Extrusion was done at velocity about 50 mm/s for 20 mm. Then an extrusion trial was done with a velocity ramp from 4 to 50 mm/s Melt fracture defects appeared at velocity above 40 mm/s.

Then boric acid was used to coat the die surface The die 6 32 mm from steel was used First the extrusion the die was exposed to open flame and heated to 600 °C to burn out any organic contamination Then powder of boric acid was supplied inside the die so that under heating boric acid was molten and inner surface of the die was coated by a glassy layer of boron oxide. Slow extrusion of molten LLDPE at velocity V about 1 mm/s through the die with the glassy layer of boric acid was done during 30 mm to establish an initial status Then molten LLDPE was extruded with a velocity ramp rising from 1 to 15 mm/s No change in the sharkskin onset was detected Nevertheless we detect suppression of the sharkskin at velocity 15 mm/s with the use of the coated die after some induction time A tentative explanation could be that during extrusion some additive polymeric material, which is present in the industrial grade of LLDPE, deposits at the die surface and react there with the curing agent. It can be zinc stearate or polyethylene oxide The last one appears in the blend under heating of LLDPE in presence of oxygen So, the use of the boric acid as a curing agent and as blending it with LLDPE results in some delay of the melt fracture onset EXAMPLE 16

The use of a siloxane fluid as Processing Additive

0 8 g of ELASTOSIL RT K from Wacker Chermie was added to a plastic bag with 1 kg of LLDPE granules. The content of the bag was thoroughly mixed by a jet of compressed air Then it was loaded into an extruder barrel and molten there. A die 3 35 22 mm from quartz glass was used for extrusion The die was heated by open flame to about 600°C just before an extrusion trial to burn out any organic contamination Sharkskin appeared at the extrudate surface at velocity 11 5 mm/s At apparent product velocity above 21 mm/s the extrudate manifested not only sharkskin but also severe rupture and peeling the skin layer off the extrudate core After extrusion of about 200 g of the blend sharkskin at velocity about 21 mm/s both sharkskin and severe rupture were diminished but not suppressed totally. So, we see some improvement in extrusion of the blend of LLDPE with the use of the siloxane fluid without a curing agent after a long while (about 1000 sec at velocity about 21 mm/s).

EXAMPLE 17 The use of a blend of siloxane fluid and boric acid as Processing Additive 0.75 g of ELASTOSIL RT K from Wacker Chemie was added to a plastic bag with 0 5 kg of LLDPE granules. The content of the bag was thoroughly mixed by a jet of compressed air 4 g of a 5% solution of tπ-isopropyl borate (0 2 g of boric acid) was poured into another plastic bag with 0 5 kg of LLDPE granules The content of this bag was thoroughly mixed and the solution was dried off by a jet of compressed air. Content of both plastic bags was mixed together and loaded into an extruder barrel, heated and molten there

A die 3 35 22 mm from quartz glass was used for extrusion The die was heated by open flame to about 600°C just before an extrusion trial to burn out any organic contamination Induction time to suppress sharkskin was measured at V about 22 mm/s First clean strips appeared at the extrudate surface after about 30 sec. In 60 sec about a half of the extrudate was clean from sharkskin and in about 110 sec all extrudate surface was already clean from any roughness. So, in extrusion of the blend of LLDPE with the same functionalized siloxane fluid as in EXAMPLE 16 but with additives of the curing agent we see total suppression of sharkskin after about 100 sec of extrusion EXAMPLE 18

The use of the viscoelastic substance cured by borax as Processing Additive in blown film extrusion

6 1 g of DOW 4-2737 was first blended with 0 1 1 g of phosphoric acid, heated to about 15O°C in an aluminum cup, and stirred vigorously till the reaction of phosphoric acid with a metal cup was finished Then 2 17 g Of AI(OH)₃ and 0 64 g of Na₂BO₄ were added to the cup and mixed The cup was heated till the blend turned into a viscoelastic substance Then the product was blended with 0 9 g of 1 ,4- Butanediol kneaded and stored in open air for three days Before extrusion the product was crushed between fingers into small crumbs The crumbs were mixed with granules of LL1201 XV at averaged concentration about 2500 ppm and polyethylene film was produced by blown film technique A ring die having outer diameter 40 mm with the gap between die lips 0 5 mm and a screw extruder were used in the experiment Before the trial the die was heated to about 600°C to burn out organic contamination and the screw extruder was purged by the neat polymer for about 2 hours At temperature of extrusion 19O°C and it took about 3 g of the additives and about 45 mm till sharkskin was suppressed At fixed rotation speed of the screw throughput of the polymer increased about 5% while pressure dropped to 64% from the reference level The time chat of pressure is presented in Figure 17 Supply of every crumb of the viscoelastic substance results first in a pressure drop for a short while, then pressure increases for a longer while and drops again 5 pierces of the additives were used and 5 peaks can be detected at the curve Pressure quickly recovered to about the reference level when no more additives were used The time chat of growing pressure is presented in Figure 18 At temperature of extrusion 23O°C and with the use the die gap 0 25 mm it took less time (30 mm) to get rid of the sharkskin and the additives were distributed inside the film more homogeneously We used a die with smaller gap to avoid bubble instabilities in blown film extrusion The produced PE film has no surface defects and it accumulates a lower static electrical charge even in comparison with the film without additives CONCLUSION

The present invention has an obvious and clear distinction from the prototype. In the closest to the prototype embodiment sinanols are added into a polyolefin resin together with a catalyst such as phosphoric acid and a curing agent such as borax That is the phosphoric acid is a catalyst for the reaction of borax with silanols while in the prototype it is a Processing Adjuvant and no curing agent is used The use of cured silanols or a blend of silanols and a curing agent provides a superior class of Processing Additives as well as extreme pressure and anti-wear additives, which are effective at low or even at trace level concentrations, capable of alleviating a number of troublesome problems both in polymer processing and in lubrication of engines and machines In particular it is useful to delay melt fracture, to avoid sticking, plate- out, fouling of extruder screws, surface defects, to diminish mold fill out difficulties and injection pressure Nor the use of viscoelastic substances cured by boron-oxide compositions in polymer processing neither the use of silanols cured by borates for Extreme Pressure and anti-wear additives is known in the state of art. It also cannot be obviously derived from state of art that the viscoelastic substances cured by a boron-oxygen composition would delay melt fracture onset or that the silanols cured by borates improve performances of lubricating liquids

Table 1. Melt fracture onset with the use of coating by liquids or viscoelastic substances

Table 2 Siloxanes cure b a blend of sodium ortho hos hate with boric acid

Table 3. Siloxanes cured by a blend of sodium ortho hos hate with borax

Table 4.

Melt fracture onset with the use of coating by a blend of cured siloxanes DOW 4-2737 (80%) u DOW 3-0133 (20%) with a filler

Claims

CLAIMS:

1 A method of processing of molten thermoplastic polymeric material in fabrication equipment wherein a layer of a viscoelastic substance cured by a compound containing boron and oxygen coats at least a portion of the rigid wall which is in a contact with said thermoplast

2. The method according to claim 1 wherein the viscoelastic substance is a product of the reaction of a curing agent based on a compound containing boron and oxygen with an additive polymeric substance reactive toward said curing agent

3 The method according to claim 2 wherein the curing agent is selected from the group of chemical compounds consisting of boron oxide, boric acids, solvable in water salts of boric acids, esters of boric acids, amines of boric acids and mixtures thereof

4 The method according to claim 2 wherein the additive polymeric substance is selected from the group of polymers bearing in their molecules at least two monofunctional radicals selected from the group consisting of hydrogen, halogen, hydroxyl, alkoxyl, carboxyl, oxime, epoxide, amine, or isocyanate

5. The method according to a claim 2 wherein the additive polymeric substance is selected from the group of polymers bearing in their molecules at least two hydroxyl radicals.

6. The method according to claim 4 or claim 5 wherein the additive polymeric substance is selected from the group consisting of functionalized siloxanes, functionalized hydrocarbons, functionalized copolymers of hydrocarbons and siloxanes, functionalized fluorinated polymers and mixtures thereof.

7. The method according to claim 2 wherein the reaction between the curing agent and the additive polymeric substance is effected in the presence of a catalyst

8. The method according to claim 7 wherein the catalyst is selected from the group of chemical compounds consisting of phosphoric acids, polyphosphoric acids, phosphorus pentoxide, salts of alkali metals and phosphoric acids, salts of alkali metals and polyphosphoric acids, salts of aluminum hydroxide and phosphoric acids, salts of ferric hydroxide and phosphoric acids, aluminum hydroxide and mixtures thereof and provided that an amount of said catalyst is selected from the condition that the ratio of the number of phosphorus atoms to the number of boron atoms is in the range from 0 01 to 1.

9. The method according to a claim 2, wherein the viscoelastic substance contains inorganic fillers in an amount from 1 to 50 weight %

10 The method according to claim 9, wherein the inorganic fillers are selected from the group of mineral powders with particles having plate-like structure consisting of mica, talc, natural and synthetic clay, hexagonal BN, and mixtures thereof.

11. The method according to claim 2 or claim 8 which comprises supply of the viscoelastic substance at least at a portion of the rigid wall of the fabrication equipment which is in a contact with the thermoplast

12 The method according to claim 2 or claim 8 which comprises blending the thermoplast with the viscoelastic substance in an amount selected from the range from 0 001 to 10 parts, per hundred parts of the thermoplast, wherein said viscoelastic substance deposits at the rigid wall of fabrication equipment which is in a contact with said thermoplast

13 The method according to claim 2 or claim 8 which comprises simultaneous or separate in time blending the thermoplast with the curing agent based on the compound containing boron and oxygen and the additive polymeric substance reactive toward said curing agent, and provided that an amount of said components is selected from the range from 0 001 to 10 parts, per hundred parts of the thermoplast, wherein said components deposit and react at the rigid wall of fabrication equipment which is in a contact with said thermoplast.

14. The method according to claim 2 or claim 8 or claim 13 wherein composition of the viscoelastic substance is selected from the condition that elasticity of the viscoelastic substance is above to that of the thermoplastic polymeric material and said elasticity is measured at maximum temperature of processing and at frequency 10 Hz

15 The method according to a claim 2 wherein processing of the molten thermoplastic polymeric material is extrusion through a die and a layer of the viscoelastic substance having at least 40 nm thickness coats at least a portion of the die land area adjacent to the die exit and having length at least 10% from the die gap width

16. A composition of the thermoplastic polymeric material comprising a main thermoplastic polymer and a processing additive in an amount selected from the range from 0.001 to 10 parts, per hundred parts of said thermoplast, wherein said thermoplast is a polyσlefin resin and said processing additive is a viscoelastic product of the reaction of silanols with a curing agent based on a compound containing boron and oxygen.

17. The composition according to claim 16 wherein the curing agent is selected from the group of chemical compounds consisting of boron oxide, boric acids, salts of boric acids and hydroxides of alkali metals, esters of boric acids, amines of boric acids and mixtures thereof and provided the condition that the ratio of the total number of alkali metal atoms to the total number of boron atoms is in the range from 0 1 to 1 18 The composition according to claim 16 or to claim 17 wherein the curing agent additionally comprises a catalyst and said catalyst is selected from the group consisting of phosphoric acids, polyphosphoric acids, phosphorus pentoxide, salts of alkali metals and phosphoric acids, salts of alkali metals and polyphosphoric acids, salts of aluminum hydroxide and phosphoric acids, salts of ferric hydroxide and phosphoric acids, aluminum hydroxide and mixtures thereof and provided that the ratio of the total number of phosphorus atoms to the total number of boron atoms is in the range from 0 01 to 1.

19 A lubricating composition comprising an oil or grease of lubricating viscosity based on non-polar hydrocarbons and having dispersed therein a minor amount of an antiwear or extreme pressure agent wherein said agent is a product of the reaction of silanols with a curing agent based on a boron-oxygen containing compound.

20 The lubricating composition according to claim 19 wherein the curing agent is selected from the group of chemical compounds consisting of boron oxide, boric acids, salts of boric acids and hydroxides of alkali metals, esters of boric acids, amines of boric acids and mixtures thereof and provided the condition that the ratio of the total number of alkali metal atoms to the total number of boron atoms is in the range from 0 1 to 1

21 The lubricating composition according to claim 19 or to claim 20 wherein the curing agent additionally comprises a catalyst and said catalyst is selected from the group consisting of phosphoric acids, polyphosphoric acids, phosphorus pentoxide, salts of alkali metals and phosphoric acids, salts of alkali metals and polyphosphoric acids and mixtures thereof and provided that an amount of said catalyst is selected from the condition that the ratio of the total number of phosphorus atoms to the total number of boron atoms is in the range from 0.01 to 1