CA1063291A - Process for the production of elastomeric polyurethane ureas - Google Patents
Process for the production of elastomeric polyurethane ureasInfo
- Publication number
- CA1063291A CA1063291A CA226,589A CA226589A CA1063291A CA 1063291 A CA1063291 A CA 1063291A CA 226589 A CA226589 A CA 226589A CA 1063291 A CA1063291 A CA 1063291A
- Authority
- CA
- Canada
- Prior art keywords
- screw
- reaction
- diamines
- parts
- diisocyanates
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/18—Stationary reactors having moving elements inside
- B01J19/20—Stationary reactors having moving elements inside in the form of helices, e.g. screw reactors
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/0895—Manufacture of polymers by continuous processes
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Polyurethanes Or Polyureas (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Polyamides (AREA)
Abstract
Abstract of the Disclosure This invention relates to a process for the solvent-free production of polyurethane ureas using chain-lengthening agents which contain aliphatically bound amino groups.
Description
Mo-1518-G-Ca LeA 15,736 PROCESS FOR THE PRODUCTION OF
ELASTOMERIC POLYURETHANE UREAS
Background of the Invention Polyisocyanates, preferably polyurethane prepolymers containing more than one free isocyanate group, are presently being used on a commercial scale to produce high-molecular weight polyureas by solvent-free reaction with aromatic diamines and/or polyamines.
It has not previously been possible, however, to obtain undiluted high-molecular weight, elastomeric polyurethane ureas from liquid polyisocyanates and aliphatic, cycloaliphatic and/or araliphatic polyamines by the usual processes because the reac-tion between the aliphatic amino groups and the isocyanate groups is so vigorous that the reactants cannot be homogeneously mixed before the reaction product solidifies. These polyureas have, therefore, in the past always been prepared as very dilute solutions. This necessarily means that either a large quantity of solvent must be transported with the reaction product from its point of production to the point where it is processed or the production of the polyurea must be followed by an additional step of evaporation which involves considerable technical and monetary expenditure.
~ o successful attempts to produce high-quality elasto-meric polyurethane ureas by a solvent-free process from liquid or low-melting polyisocyanates(optionally with one or more other reactants which contain more than one Zerewitinoff-active group) and liquid or low-melting aliphatic, cyclo-aliphatic and/or araliphatic diamines (hereinafter referred to as aliphatic diamines) have previously been recorded. In 30 German Offenlegungsschrift No. 2,059,570 for example, a continuous, one-step process for the production of thermo-LeA 15,736 ~06329'1 plastic polyurethane has been disclosed, in which a) a diisocyanate, polymeric diol, difunctional chain-lengthening agent and catalyst are mixed in a first zone;
b~ the reaction mixture is then passed through a second zone in which it is mixed under high shearing forces; and c) the reaction mixture is continuously transferred to a molding zone in which it is shaped by extrusion, with the proviso that as the reaction mixture passes through the individual zones, its temperature is controlled so that its viscosity remains substantially constant at about 1000 to 10,000 poises in all the zones.
Owing to the vigorous reaction of the aliphatic amino groups with the isocyanate groups, it is difficult, if not impossible, to maintain the su~stantial consistency of viscosity of the molten product at about 1000 and 10,000 poises in every part of the screw. It is also found that even when glycols which are comparatively slow reacting and much easier to work with, are used as chain-lengthening agents according to German Offenlegungsschrift No. 2,059,570, it is not possible to obtain homogeneous products which are free from lumps and gel particles.
Description of the Invention It has now surprisingly been found, however, that even when highly reactive diamines are used as chain-lengthening agents it is possible to obtain molten high-quality, elasto-meric polyurethane ureas which are free from the inhomogeneities mentioned above. The most important condition which is LeA 15,736 -2-~063291 required to achieve this, is that the mixture of reactants should be exposed to a high velocity gradient by means of vigorously mixing-kneading elements while it is in a reaction phase in which the viscosity is still low (100 to 1000 poises, preferably 200 to 700). Kneading zones in later phases of the reaction are of only minor importance.
This invention therefore relates to a process for the continuous production of elastomeric polyurethane ureas by reaction'of (a) diisocyanates and optionally polyisocyanates, (b) aliphatic cycloaliphatic and/or araliphatic primary or secondary diamines and (c) optionally other active hydrogen containing compounds which preferably contain an average of at least 1.8 Zerewitinoff-active groups, in self-cleaning, double-shaft screws in which both shafts rotate in the same direction, at temperatures between about 110 and about 280C and at viscosities in the range of about 0.1 to about 3000 poises during the reaction in the screw, which is characterized in that for the purpose of obtaining a homogeneous end product which is free from lumps, the critical reaction phase, in which the reaction mixture is very sticky and has a viscosity in the range of about 100 to about 1000 poises, is carried out in a zone of the screw which is situated in the front part of the housing and which contains vigorously mixing-kneading elements operating at kneading frequencies of about 1 to about 20 Hertz and which elements produce a velocity gradient of more than about 2000 sec 1 in the radial clearance between the screw comb and wall of the housing.
If the conditions according to the invention are ob-served when carrying out the process, it is possible to obtain a homogeneous product which is free from the gel particles and lumps which invariably occur when polyurethane urea elasto-LeA 15,736 ~3~
1063Z9l m~ s are synthesized in screw extruders without the controlsprovided by the invention. The elastomeric polyurea being produced is kept in a thermoplastic state by the heat released by the exothermic reaction and the heat of friction produced ; in the extruder as well as by heat applied externally to the machine housing so that the reaction product can easily be extruded to form, for example, strands, or the product may be otherwise shaped at the end of the machine.
The starting components used for carrying out the pro-L0 cess according to the invention may be essentially any organicdiisocyanate and include, aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic diisocyanates of the kind described e.g. by W. Siefgen in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136. Examples include ethylene diisocyanate;
tetramethylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate, trimethyl hexamethylene-1,6-diisocyanate, dodecane-1,12-diiso-cyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and 1,4-diisocyanate and any mixtures of these isomers, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (see e.g. German Auslegeschrift 1,202,785); hexahydrotolylene-2,4 and 2,6-diiso-cyanate and any mixtures of these isomers, perhydrodiphenyl-methane-2,4'- and/or 4,4'-diisocyanate; phenylene-1,3 and 1,4-diisocyanate, tolylene-2,4- and 2,6-diisocyanate and any mixtures of these isomers, diphenylmethane-2,4'- and/or 4,4'-diisocyanate, and diisocyanates which are obtained by telomeri-zation as described in Belgian Patent 723,640.
The above mentioned diisocyanates may be used together with a polyisocyanate, the polyisocyanate being used in amounts which may be up to 15 mol % (based on the diiso-cyanate). The amount of polyisocyanate used must be sufficientlylow to ensure that the polyurea discharged from the screw LeA 15,736 ~4~
extruder will still be in a fusible or thermoplastic state.
If a substantial quantity of higher functional isocyanates is used, this must generally be compensated by adding hydroxyl or amino compounds which have an average functionality of less than two in order to prevent excessive chemical crosslinking of the product delivered from the screw extruder. It is, of course possible to carry out the reaction so that chemical crosslinking of the elastomer subsequently takes place during storage (e.g. by using an excess of compounds which contain isocyanate groups). The following are examples of suitable higher-functional isocyanates: triphenylmethane-4,4',4"-triiso-cyanate, polyphenylpolymethylene polyisocyanates which can be obtained by aniline-formaldehyde condensation followed by phosgenation and which have been described in British Patents lS 874,430 and 848,671; perchlorinated aryl polyisocyanates of the kind described in German Auslegeschrift 1,157,601; polyisocyanates which contain carbodiimide groups as described in German Patent 1,092,007; the diisocyanates described in U.S. Patent 3,492,330, polyisocyanates which contain allophanate groups as described in British Patent 994,890, Belgian Patent No.
761,626 and published Dutch Patent Application No. 7,102,524, polyisocyanates which contain isocyanurate groups as described in German Patents 1,022,789, 1,222,067 and 1,027,394 and in German Offenlegungsschrifts 1,929,034 and 2,004,048, poly-isocyanates which contain urethane groups as described in Belgian Patent 752,261 or in U.S. Patent 3,394,164, polyiso-cyanates which contain acylated urea groups as described in German Patent 1,230,778, polyisocyanates which contain biuret groups as described in German Patent 1,101,394 in British Patent 889,050 and in French Patent 7,017,514, polyisocyanates which are prepared by telomerization reactions as described in Belgian Patent 723,640, polyisocyanates which contain ester LeA 15,736 -5-groups as described in British Patents 965,474 and 1,072,956 U.S. Patent 3,567,763 and German Patent 1,231,688; and reaction products of the above-mentioned isocyanates with acetals as described in German Patent 1,072,385.
The distillation residues which are obtained from the commercial production of isocyanates and which still contain isocyanate groups may also be used, optionally dissolved in one or more of the above-mentioned polyisocyanates. Any mixtures of the above-mentioned polyisocyanates may also be used.
The following are examples of aliphatic diamines which may be used as chain-lengthening agents according to the invention either alone or as mixtures: ethylene diamine, tetramethylene-1,4-diamine; hexamethylene-1,6-diamine; N,N'-diisobutyl-hexamethylene-1,6-diamine; undecamethylene-l,ll-diamine; dodecamethylene-1,12-diamine; cyclobutane-1,3-diamine;
cyclohexane-1,3- and -1,4-diamine and mixtures thereof; l-amino-3,5,5-trimethyl-5-aminomethyl cyclohexane, hexahydrotolylene-
ELASTOMERIC POLYURETHANE UREAS
Background of the Invention Polyisocyanates, preferably polyurethane prepolymers containing more than one free isocyanate group, are presently being used on a commercial scale to produce high-molecular weight polyureas by solvent-free reaction with aromatic diamines and/or polyamines.
It has not previously been possible, however, to obtain undiluted high-molecular weight, elastomeric polyurethane ureas from liquid polyisocyanates and aliphatic, cycloaliphatic and/or araliphatic polyamines by the usual processes because the reac-tion between the aliphatic amino groups and the isocyanate groups is so vigorous that the reactants cannot be homogeneously mixed before the reaction product solidifies. These polyureas have, therefore, in the past always been prepared as very dilute solutions. This necessarily means that either a large quantity of solvent must be transported with the reaction product from its point of production to the point where it is processed or the production of the polyurea must be followed by an additional step of evaporation which involves considerable technical and monetary expenditure.
~ o successful attempts to produce high-quality elasto-meric polyurethane ureas by a solvent-free process from liquid or low-melting polyisocyanates(optionally with one or more other reactants which contain more than one Zerewitinoff-active group) and liquid or low-melting aliphatic, cyclo-aliphatic and/or araliphatic diamines (hereinafter referred to as aliphatic diamines) have previously been recorded. In 30 German Offenlegungsschrift No. 2,059,570 for example, a continuous, one-step process for the production of thermo-LeA 15,736 ~06329'1 plastic polyurethane has been disclosed, in which a) a diisocyanate, polymeric diol, difunctional chain-lengthening agent and catalyst are mixed in a first zone;
b~ the reaction mixture is then passed through a second zone in which it is mixed under high shearing forces; and c) the reaction mixture is continuously transferred to a molding zone in which it is shaped by extrusion, with the proviso that as the reaction mixture passes through the individual zones, its temperature is controlled so that its viscosity remains substantially constant at about 1000 to 10,000 poises in all the zones.
Owing to the vigorous reaction of the aliphatic amino groups with the isocyanate groups, it is difficult, if not impossible, to maintain the su~stantial consistency of viscosity of the molten product at about 1000 and 10,000 poises in every part of the screw. It is also found that even when glycols which are comparatively slow reacting and much easier to work with, are used as chain-lengthening agents according to German Offenlegungsschrift No. 2,059,570, it is not possible to obtain homogeneous products which are free from lumps and gel particles.
Description of the Invention It has now surprisingly been found, however, that even when highly reactive diamines are used as chain-lengthening agents it is possible to obtain molten high-quality, elasto-meric polyurethane ureas which are free from the inhomogeneities mentioned above. The most important condition which is LeA 15,736 -2-~063291 required to achieve this, is that the mixture of reactants should be exposed to a high velocity gradient by means of vigorously mixing-kneading elements while it is in a reaction phase in which the viscosity is still low (100 to 1000 poises, preferably 200 to 700). Kneading zones in later phases of the reaction are of only minor importance.
This invention therefore relates to a process for the continuous production of elastomeric polyurethane ureas by reaction'of (a) diisocyanates and optionally polyisocyanates, (b) aliphatic cycloaliphatic and/or araliphatic primary or secondary diamines and (c) optionally other active hydrogen containing compounds which preferably contain an average of at least 1.8 Zerewitinoff-active groups, in self-cleaning, double-shaft screws in which both shafts rotate in the same direction, at temperatures between about 110 and about 280C and at viscosities in the range of about 0.1 to about 3000 poises during the reaction in the screw, which is characterized in that for the purpose of obtaining a homogeneous end product which is free from lumps, the critical reaction phase, in which the reaction mixture is very sticky and has a viscosity in the range of about 100 to about 1000 poises, is carried out in a zone of the screw which is situated in the front part of the housing and which contains vigorously mixing-kneading elements operating at kneading frequencies of about 1 to about 20 Hertz and which elements produce a velocity gradient of more than about 2000 sec 1 in the radial clearance between the screw comb and wall of the housing.
If the conditions according to the invention are ob-served when carrying out the process, it is possible to obtain a homogeneous product which is free from the gel particles and lumps which invariably occur when polyurethane urea elasto-LeA 15,736 ~3~
1063Z9l m~ s are synthesized in screw extruders without the controlsprovided by the invention. The elastomeric polyurea being produced is kept in a thermoplastic state by the heat released by the exothermic reaction and the heat of friction produced ; in the extruder as well as by heat applied externally to the machine housing so that the reaction product can easily be extruded to form, for example, strands, or the product may be otherwise shaped at the end of the machine.
The starting components used for carrying out the pro-L0 cess according to the invention may be essentially any organicdiisocyanate and include, aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic diisocyanates of the kind described e.g. by W. Siefgen in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136. Examples include ethylene diisocyanate;
tetramethylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate, trimethyl hexamethylene-1,6-diisocyanate, dodecane-1,12-diiso-cyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and 1,4-diisocyanate and any mixtures of these isomers, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (see e.g. German Auslegeschrift 1,202,785); hexahydrotolylene-2,4 and 2,6-diiso-cyanate and any mixtures of these isomers, perhydrodiphenyl-methane-2,4'- and/or 4,4'-diisocyanate; phenylene-1,3 and 1,4-diisocyanate, tolylene-2,4- and 2,6-diisocyanate and any mixtures of these isomers, diphenylmethane-2,4'- and/or 4,4'-diisocyanate, and diisocyanates which are obtained by telomeri-zation as described in Belgian Patent 723,640.
The above mentioned diisocyanates may be used together with a polyisocyanate, the polyisocyanate being used in amounts which may be up to 15 mol % (based on the diiso-cyanate). The amount of polyisocyanate used must be sufficientlylow to ensure that the polyurea discharged from the screw LeA 15,736 ~4~
extruder will still be in a fusible or thermoplastic state.
If a substantial quantity of higher functional isocyanates is used, this must generally be compensated by adding hydroxyl or amino compounds which have an average functionality of less than two in order to prevent excessive chemical crosslinking of the product delivered from the screw extruder. It is, of course possible to carry out the reaction so that chemical crosslinking of the elastomer subsequently takes place during storage (e.g. by using an excess of compounds which contain isocyanate groups). The following are examples of suitable higher-functional isocyanates: triphenylmethane-4,4',4"-triiso-cyanate, polyphenylpolymethylene polyisocyanates which can be obtained by aniline-formaldehyde condensation followed by phosgenation and which have been described in British Patents lS 874,430 and 848,671; perchlorinated aryl polyisocyanates of the kind described in German Auslegeschrift 1,157,601; polyisocyanates which contain carbodiimide groups as described in German Patent 1,092,007; the diisocyanates described in U.S. Patent 3,492,330, polyisocyanates which contain allophanate groups as described in British Patent 994,890, Belgian Patent No.
761,626 and published Dutch Patent Application No. 7,102,524, polyisocyanates which contain isocyanurate groups as described in German Patents 1,022,789, 1,222,067 and 1,027,394 and in German Offenlegungsschrifts 1,929,034 and 2,004,048, poly-isocyanates which contain urethane groups as described in Belgian Patent 752,261 or in U.S. Patent 3,394,164, polyiso-cyanates which contain acylated urea groups as described in German Patent 1,230,778, polyisocyanates which contain biuret groups as described in German Patent 1,101,394 in British Patent 889,050 and in French Patent 7,017,514, polyisocyanates which are prepared by telomerization reactions as described in Belgian Patent 723,640, polyisocyanates which contain ester LeA 15,736 -5-groups as described in British Patents 965,474 and 1,072,956 U.S. Patent 3,567,763 and German Patent 1,231,688; and reaction products of the above-mentioned isocyanates with acetals as described in German Patent 1,072,385.
The distillation residues which are obtained from the commercial production of isocyanates and which still contain isocyanate groups may also be used, optionally dissolved in one or more of the above-mentioned polyisocyanates. Any mixtures of the above-mentioned polyisocyanates may also be used.
The following are examples of aliphatic diamines which may be used as chain-lengthening agents according to the invention either alone or as mixtures: ethylene diamine, tetramethylene-1,4-diamine; hexamethylene-1,6-diamine; N,N'-diisobutyl-hexamethylene-1,6-diamine; undecamethylene-l,ll-diamine; dodecamethylene-1,12-diamine; cyclobutane-1,3-diamine;
cyclohexane-1,3- and -1,4-diamine and mixtures thereof; l-amino-3,5,5-trimethyl-5-aminomethyl cyclohexane, hexahydrotolylene-
2,4- and 2,6-diamine and mixtures thereof; perhydro-2,4'- and 4,4'-diaminodiphenylmethane; p-xylylene diamine; bis-(3-amino-propyl)-methylamine and the like. Hydrazine and substituted hydrazines such as methyl hydrazine; N,N'-dimethyl hydrazine and their homologs as well as acid dihydrazides such as carbodihydrazide; oxalic acid dihydrazide; the dihydrazides of malonic acid, succinic acid, glutaric acid, adipic acid, ~-methyl adipic acid, sebacic acid, hydracrylic acid and tere-phthalic acid, semicarbazido-alkylene hydrazides such as ~-semi-carbazido-propionic acid hydrazide (see e.g. German Offenlegungsschrift 1,770,591) semicarbazido-alkylene carbazic acid esters such as 2-semicarbazido-ethyl-carbazic ester (see e.g. German Offenlegungsschrift 1,918,504) and amino semi-LeA 15,736 -6-1063Z9l carbazido compounds such as ~-aminoethyl-semicarbazido carbonate (see e.g. German Offenlegungsschrift No. 1,902,931), may also be used.
Higher-functional amines may also be added and used in a similar manner to the higher-functional isocyanates.
In the process according to the invention, the diiso-cyanates and optionally polyisocyanates are preferably reacted, either before or during the reaction with aliphatic diamines, with other compounds, preferably with molecular weights of 500 to 10,000 which contain an average of at least 1.8 Zerewitinoff-active groups per molecule. These compounds used according to the invention which contain Zerewitinoff-active groups may be compounds which contain amino, thiol or carboxyl groups but are preferably polyhydroxyl compounds, in particular those with an average of 1.8 to ~ hydroxyl groups and especially those with a molecular weight of 500 to 10,000 preferably 600 to 6000 such as polyesters, polyethers, poly-thioethers, polyacetals, polycarbonates and polyester amides which contain at least two, generally two to eight but pre-ferably two to four hydroxyl groups, of the kind which aregenerally known for the production of polyurethanes.
Suitable polyesters with hydroxyl groups include the reaction products of polyhydric alcohols, perferably dihydric alcohols to which trihydric alcohols, and polybasic, preferably dibasic carboxylic acids may be added. Instead of free poly-carboxylic acids, the corresponding polycarboxylic acid anhydrides or polycarboxylic acid esters of lower alcohols or mixtures thereof may be used for the production of the poly-esters. The polycarboxylic acids may be aliphatic, cyclo-aliphatic, aromatic and/or heterocyclic and may be substitutedwith halogen atoms, and/or may be unsaturated. The following LeA 15,736 -7-are mentioned as examples: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic acid anhydride; tetrahydro-phthalic acid anhydride; hexahydrophthalic acid anhydride, tetra-chlorophthalic acid anhydride; endomethylene tetrahydrophthalicacid anhydride, glutaric acid anhydride; maleic acid, maleic acid anhydride, fumaric acid, dimeric and trimeric fatty acids such as oleic acid which may be mixed with monomeric fatty acids, dimethyl terephthalate and bis-glycol terephthalate. Suitable polyhydric alcohols include, ethylene glycol, propylene-1,2 and 1,3-glycol, butylene-1,4- and 2,3-glycol, hexane-1,6-diol, octane-1,8-diol, neopentyl glycol, cyclohexane dimethanol (1,4-bis-hydroxymethyl cyclohexane); 2-methyl-propane-1,3-diol;
glycerol, trimethylolpropane, hexane-1,2,6-triol; butane-1,2,4-trio~ trimethylolethane; pentaerythritol, diethylene glycol,triethylene glycol, tetraethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycols. The polyesters may also contain carboxyl end groups. Mono and polyesters of lactones which contain an average of more than 1.8 hydroxyl groups such as, -caprolactone, or hydroxycarboxylic acids such as ~-hydroxy-caproic acid may also be used.
The polyethers used according to the invention which contain at least two, generally two to eight and preferably two or three hydroxyl groups are also generally known and may be prepared by the polymerization of epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin in the presence of boron trifluoride, or by addition of these epoxides, either as mixtures or successively, to starter components which contain reactive hydrogen atoms such as water, alcohols or amines. Examples of such qtarter components include ethylene glycol, propylene-LeA 15,736 -8-1,3 or 1,2-glycol, trimethylolpropane, 4,4'-dihydroxy-diphenyl-propane, aniline, ammonia, ethanolamine or ethylene diamine.
Sucrose polyethers such as those described in German Auslegeschriftens 1,176,358 and 1,064,938 may also be used according to the invention. It is frequently preferred to use polyethers which contain substantial amounts of primary hydroxyl groups (up to 90~ by weight, based on all the hydroxyl groups present in the polyether). Polyethers which are modified with vinyl polymers!, for example the polyethers which can be o~tained by polymerizing styrene and acrylonitrile in the presence of polyethers (U.S. Patents 3,383,351, 3,304,273, 3,523,093 and
Higher-functional amines may also be added and used in a similar manner to the higher-functional isocyanates.
In the process according to the invention, the diiso-cyanates and optionally polyisocyanates are preferably reacted, either before or during the reaction with aliphatic diamines, with other compounds, preferably with molecular weights of 500 to 10,000 which contain an average of at least 1.8 Zerewitinoff-active groups per molecule. These compounds used according to the invention which contain Zerewitinoff-active groups may be compounds which contain amino, thiol or carboxyl groups but are preferably polyhydroxyl compounds, in particular those with an average of 1.8 to ~ hydroxyl groups and especially those with a molecular weight of 500 to 10,000 preferably 600 to 6000 such as polyesters, polyethers, poly-thioethers, polyacetals, polycarbonates and polyester amides which contain at least two, generally two to eight but pre-ferably two to four hydroxyl groups, of the kind which aregenerally known for the production of polyurethanes.
Suitable polyesters with hydroxyl groups include the reaction products of polyhydric alcohols, perferably dihydric alcohols to which trihydric alcohols, and polybasic, preferably dibasic carboxylic acids may be added. Instead of free poly-carboxylic acids, the corresponding polycarboxylic acid anhydrides or polycarboxylic acid esters of lower alcohols or mixtures thereof may be used for the production of the poly-esters. The polycarboxylic acids may be aliphatic, cyclo-aliphatic, aromatic and/or heterocyclic and may be substitutedwith halogen atoms, and/or may be unsaturated. The following LeA 15,736 -7-are mentioned as examples: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic acid anhydride; tetrahydro-phthalic acid anhydride; hexahydrophthalic acid anhydride, tetra-chlorophthalic acid anhydride; endomethylene tetrahydrophthalicacid anhydride, glutaric acid anhydride; maleic acid, maleic acid anhydride, fumaric acid, dimeric and trimeric fatty acids such as oleic acid which may be mixed with monomeric fatty acids, dimethyl terephthalate and bis-glycol terephthalate. Suitable polyhydric alcohols include, ethylene glycol, propylene-1,2 and 1,3-glycol, butylene-1,4- and 2,3-glycol, hexane-1,6-diol, octane-1,8-diol, neopentyl glycol, cyclohexane dimethanol (1,4-bis-hydroxymethyl cyclohexane); 2-methyl-propane-1,3-diol;
glycerol, trimethylolpropane, hexane-1,2,6-triol; butane-1,2,4-trio~ trimethylolethane; pentaerythritol, diethylene glycol,triethylene glycol, tetraethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycols. The polyesters may also contain carboxyl end groups. Mono and polyesters of lactones which contain an average of more than 1.8 hydroxyl groups such as, -caprolactone, or hydroxycarboxylic acids such as ~-hydroxy-caproic acid may also be used.
The polyethers used according to the invention which contain at least two, generally two to eight and preferably two or three hydroxyl groups are also generally known and may be prepared by the polymerization of epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin in the presence of boron trifluoride, or by addition of these epoxides, either as mixtures or successively, to starter components which contain reactive hydrogen atoms such as water, alcohols or amines. Examples of such qtarter components include ethylene glycol, propylene-LeA 15,736 -8-1,3 or 1,2-glycol, trimethylolpropane, 4,4'-dihydroxy-diphenyl-propane, aniline, ammonia, ethanolamine or ethylene diamine.
Sucrose polyethers such as those described in German Auslegeschriftens 1,176,358 and 1,064,938 may also be used according to the invention. It is frequently preferred to use polyethers which contain substantial amounts of primary hydroxyl groups (up to 90~ by weight, based on all the hydroxyl groups present in the polyether). Polyethers which are modified with vinyl polymers!, for example the polyethers which can be o~tained by polymerizing styrene and acrylonitrile in the presence of polyethers (U.S. Patents 3,383,351, 3,304,273, 3,523,093 and
3,110,695 and German Patent 1,152,536) and polybutadienes which contain hydroxyl groups are also suitable.
Among the polythioethers usable are the condensation products of thiodiglycol with itself and/or with other glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or amino alcohols. The products obtained are either polythio mixed ethers, polythioether esters or polythio ether ester amides, depending on the co-component.
Suitable polyacetals include the compounds which can be prepared from glycols such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxy-diphenyldimethylmethane, hexanediol, and formaldehyde. Polyacetals suitable for the purpose of the invention may also be prepared by the polymerization of cyclic acetals.
Suitable polycarbonates with hydroxyl groups include, those which can be prepared by reacting diols such as propane-1,3-diol, butane-1,4-diol and/or hexane-1,6-diol, diethylene glycol, triethylene glycol, tetraethylene glycol and optionally 2,2-bis-(4-hydroxyphenyl)-propane and/or the corresponding hydrogenated compound with phosgene or preferably with diaryl ~eA 15,736 -9-1063Z9l carbonates such as diphenyl carbonate.
Suitable polyester amides and polyamides include the predominantly linear condensates obtained from polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and mixtures thereof.
Polyhydroxyl compounds which already contain urethane or urea groups and modified or unmodified natural polyols such as castor oil, carbohydrates or starch are also suitable.
Products of addition of alkylene oxide to phenol formaldehyde resins or to urea formaldehyde resins may also be used accord-ing to the invention.
Other examples of the many types of compounds which may be used for carrying out the process of the invention have been described in High Polymers, Volume XVI, "Polyurethanes, Chemistry and Technology" by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32-42 and pages 44-54 and Volume II, 1964, pages 5-6 and 198-199 and in Kunststoff-Handbuch, Volume VII, Vieweg-Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages 45-71.
In addition to the aliphatic diamines used according to the invention, up to 95 mol ~, preferably less than 80 mol %
(based on the total quantity of chain-lengthening agents) and most preferably less than 50 mol % of low-molecular weight dialcohols and/or polyalcohols (molecular weight 62 to 500) may be used. Suitable low-molecular weight dialcohols and/or poly-alcohols include ethylene glycol, propylene-1,2- and 1,3-glycol, butylene-1,4- and 2,3-glycol, hexane-1,6-diol, octane-1,8-diol, neopentyl glycol, cyclohexane dimethanol (1,4-bis-hydroxymethyl cyclohexane), 2-methyl-propane-1,3-diol, xylylene glycol, hydroquinone-bis-~-hydroxyethyl ether, glycerol, LeA 15,736 -10-trimethylolpropane, hexane-1,2,6-trio~ butane-1,2,4-triol, trimethylolether and pentaerythritol.
Suitable examples of aromatic diamines which may be used herein include the bisanthranilic acid estersas described in German Offenlegungsschriften 2,040,644 and 2,160,590; 3,5- and 2,4-diaminobenzoic acid esters as described in German Offenlegungsschrift 2,025,900; diamines with ester groups as described in German Offenlegungsschriften 1,803,635; 2,040,650 and 2,160,589; 3,3'-dichloro-4,4'-diamino-diphenylmethane;
tolylene diamine; 4,4'-diaminodiphenylmethane; and 4,4'-diamino-diphenyl disulphide.
Compounds which are monofunctional in their reaction with isocyanates may also be used as so-called "chain-breaking agents" in proportions of 0.01 to 10% by weight, based on the polyurethane solid content. Monofunctional compounds of this kind include monoamines such as butylamine dibutylamine, octylamine, stearylamine, N-methyl stearylamine, pyrrolidine, piperidine and cyclohexylamine and monoalcohols such as butanol 2-ethyl hexanol, octanol, decanol, the various amyl alcohols, cyclohexanol, ethylene glycol monoethyl ether and the like.
As already mentioned above, the average functionality of all the components used for the reaction should not be substantially greater than two in order to ensure that elasto-meric polyurethane ureas which are still fusible or thermo-plastic will be obtained during the reaction in the screwextruder.
The sequence in which the various reactants are reacted with the diisocyanate and/or the polyisocyanate may be varied. The reaction may be carried out by single-stage or multistage processes but it is preferable if the reaction with LeA 15,736 -11-the hydroxyl-containing compound or compounds is carried out either shortly before or during the reaction with the diamines.
The individual reactants may be introduced into the screw extruder at different points. According to one particular vari-ation of the process, an isocyanate prepolymer is first pre-pared in a mixing and/or reaction vessel (e.g. in a tank or in a mixing head, static mixer or mixing nozzle) from the diisocyanate and/or polyisocyanate and the higher-molecular weight compound or compounds containing an average of at least 1.8 Zerewitinoff-active groups in the molecule and optionally lower molecular weight dialcohols and/or polyalcohols and/or aromatic diamines. This prepolymer is then reacted with the diamines with aliphatically bound amino groups used according to the invention in the screw extruder.
A major advantage of the process according to the invention compared with the discontinuous method previously employed is that it may also be carried out as a one-shot process. In a static reaction vessel such as a iank, it is generally not possible to react polyisocyanates, polyols and aliphatic polyamines simultaneously because polyisocyanates and polyamines rapidly react to form ureas which are insoluble in tne reaction mixture, precipitate and result in inhomogeneities in the end product.
The optionallow-molecular weight diols and/or polyols, aromatic diamines and mono-functional chain-breaking agents may first be mixed eitner with the higher-molecular weight compounds which contain Zerewitinoff-active groups`or with the aliphatic diamines or polyisocyanates, or they may be added separately to the reaction mixture.
In another variation of the process according to the invention, higher-molecular weight compounds which contain LeA 15,736 -12-1063Z9l aliphatically bound amino end groups (so-called amino prepolymers) are used as starting materials which are reacted with the di-isocyanates and optionally polyisocyanates in the screw ex-truder, the isocyanate component acting as chain-lengthening agent. Amino prepolymers of this kind may be prepared by reacting diamines and/or polyamines with a subequivalent amount of diisocyanates or by hydrazinolysis of monoaryl carbonates of the polyesters or polyethers described above. A detailed des-cription of the preparation of amino prepolymers which may be used according to the invention may be found in German Offenlegungsschrift 1,694,152 and U.S. Patent 3,625,871.
Although this is not essential for the process accord-ing to the invention, the reaction may also be carried out in the presence of organic solvents which do not react with isocyanate groups and their reactants, such as esters, ethers, hydrocarbons, halogenated hydrocarbons or peralkylated acid amides.
The reaction of isocyanate groups with other reactants may be accelerated with the usual catalysts for isocyanate reactions in quantities of 0.0001 to 5% by weight, preferably 0.0005 to 2~ by weight (based on the polyurethane solid content).
Suitable catalysts include tertiary amines such as triethyl-amine, N-methyl morpholine, N,N,N',N'-tetramethyl-ethylene diamine, 1,4-diazabicyclo-(2,2,2`-octane, N,N-dimethyl benzyl-amine and 2-methyl-imidazole, organic metal compounds such as zinc octoate, tin(II)-octoate, dibutyl tin(IV)-dilaurate, iron acetyl acetonate, titanium tetrabutylate and dioctyl tin(IV) diacetate and bases such as tetraalkyl ammonium hydroxides, sodium hydroxide, sodium phenolate and the like. However, a catalyst is not required.
Other suitable catalysts which may be used according LeA 15,736 -13-1063Z9l to the invention and details concerning the action of the catalysts are described in Kunststoff~andbuch, Volume VII, published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages 96 to 102.
In the process according to the invention, the isocyan~te groups and the Zerewitinoff-active groups, including the primary and secondary aliphatic amino groups, are generally used in stoichiometric proportions. The ratio of isocyanate groups to groups which are reactive with them is generally between 0.80 and 1.3, preferably between 0.90 and 1.10. Deviations from these ratios are, of course, permissible for special purposes.
The molar ratio of higher-molecular weight compounds which contain Zerewitinoff-active groups to the chain-lengthening agents (i.e. the low molecular weight aliphatic diamines and optionally aromatic diamines or low molecular weight diols and/or polyols), is generally between 10:1 and 1:20, preferably between 5:2 and 1:15.
The process according to the invention may be carried out in the presence of the usual lubricants, dyes, pigments and other additives such as fillers and reinforcing substances.
The invention is illustrated in Figures 1 through 7.
Figure 1 represents a two-shaft screw extruder equipped with means for zone-wise heating or cooling of the housing, and alternate kneading zones and self-cleaning screw conveyor zones.
Figures 2 to 6 represent various types of suitable kneading elements.
Figure 7 shows kneading discs arranged in the form of a screw thread and staggered like spiral staircases (in the direction of delivery) at the beginning of the screw shafts.
~ - 14 -LeA 15,736-Ca `' -1063Z9l When carrying out the process according to the invention, the reactants are delivered in known manner, e.g. from gear wheel, piston or membrane pumps. They may be partly mixed before their entry into the screw extruder, as already described above.
The reactants are introduced into a multi-shaft screw extruder either singly or already partly mixed. The extruder used is known per se and is commercially available.
LeA 15,736-Ca - 14a -It may be a self-cleaning, two-shaft screw extruder with both shafts rotating in the same sense (such as, for example, the screw 1 in Figure 1) equipped with means for zonewise heating or cooling of the housing (2-6 in Figure 1), e.g. by means of a liquid heat transfer medium. If the reactants mentioned above are reacted continuously in single-shaft or multi-shaft screw extruders without the particular measures according to the invention, the extruded melt invariably contains gel-like particles or lumps. This may be explained on the grounds that parts of the reaction mixture, which are very sticky during a critical phase of the reaction during which it has a viscosity of about 100 to about 1000 poises, remain too long and stick to the screw shafts and walls of the housing (even in the case of multi-shaft extruders with screws intermeshing with the necessary clearance). These particles which differ from the main mass of the reaction mixture as regards their residence time in the extruder and their reaction history, therefore, also in their properties, subsequently become detached by accident and incorporated in the elastomer. In addition, lumps may occur due to insufficient homogenization before the reaction.
To prevent this formation of lumps, the process accord-ing to the invention is carried out at a relatively high temperature, a temperature above the softening point of the elastomeric polyurea formed in the extruder being employed even at the beginning of the screw, and the melt is subjected to a high velocity gradient (more than about 2000 sec 1 in the clearance between screws and the wall of the housing) while it is still a relatively low viscosity melt in the critical reaction phase defined above (viscosity between about 100 and about 1000 poises) and at the same time, the kneading elements subject this melt to a rhythmic kneading movement at frequencies LeA 15,736 -15-~63291 of 1 to 20 Hertz, preferably 5 to 15 Hertz.
These measures cause the substance to be vigorously mixed in the radial direction so that the reaction proceeds homogeneously and no substance can adhere to the screw shafts and walls of the housing. The reaction is preferably carried out in self-cleaning, two-shaft screw extruders with both shafts rotating in the same sense, and at temperatures between 110 and 280C and with the usual radial clearance in such extruders of 0.05 and 0.6 mm, depending on the size of the screws, and at screw rotations of 70 revs. per min. Thus, for example, the speed of rotation which can successively be employed in such a two-shaft screw extruder in which the screws have an external diameter of 53 mm and a radial clearance of 0.2 mm is 210 revs. per min. which corresponds to a maximum velocity gradient in the sheared product of 2920 sec 1 between the external diameter of the screw and the housing, in other words, calculated in the radial clearance. Suitable kneading elements are, for example, those described in German Patents 813,154 and 940,109 and are also shown in Figures 2-6 which represent prosmatic discs of various geometrical shapes which scrape against each other in every position except for the snall clearance which is mechanically necessary, and which cooperate with the ribs (18, 19 in Figures 2-6) of the housing to exert high shearing and frictional forces on the material which is being mixed. A plurality of such kneading discs stag-gered on the shaft in the circumferential direction amounts to a kneading zone (7, 8, 9 in Figure 1).
Since such a kneading zone generally hinders the flow of substances passing continuously through the extruder housing in the axial direction, it must be preceded by a self-cleaning screw conveyor zone (10, 11, 12 as shown in Figure 1) LeA 15,736- Ca ~ - 16 -1., in which the pressure is built up. The geometry of such aconveyor zone has been described in German Patent 862,668.
For producing polyureas from isocyanates and aliphatic amines, it should be as short as possible so that the time of stay of the reaction mixture in this zone is preferably only about 1 to 10 seconds. The critical stage, in which the substance is particularly sticky and therefore liable to form lumps in the known processes, is in this case situated in the first kneading zone (7), in whicl~ the formation of lumps is prevented under the conditions mentioned above. The highly viscous product of the more advanced reaction (final viscosity up to 3000 poises) can be handled in the screw conveyor zones (10 or 11, 12 and 13) without reduction in quality. The critical reaction stage must be localized in the kneading zone (7) by suitable temperature control of the various zones of the housing (2,3) and, optionally, by the addition of activators to accelerate the reaction.
Kneading discs arranged in the form of a screw thread and staggered like a spiral staircase (in the direction of delivery) at the beginning of the screw shafts as shown in Figure 7 have also been found to be suitable according to the invention. In addition to the desired mixing action in the radial direction, they also have a conveying action in the axial direction so that the screw conveyor zone (10) and kneading zone (7) in Figure 1 may be replaced by a conveying-kneading zone shown in Figure 7.
According to another preferred embodiment of the ïnve-ntion, delïvery of the reacting substance through the kneading zone, which in this case is situated at the beginning of the machine, is achieved by means of a hydraulic bias pressure produced by the delivery pumps of the reactants. The liquid required for this purpose is pumped into the closed LeA 15,736 -17-1063Z9l machine.
It is essential for carrying out the process according to the invention that the di- and/or polyisocyanate and the aliphatic diamine should immediately be vigorously mixed as soon as they are brought together in the screw extruder, preferably a a temperature above the softening point of the product delivered from the extruder.
Owing to the great speed with which they react, the isocyanate component and amino component generally cannot be mixed beforehand but must be introduced separately into the screw extruder, as indicated schematically by the two arrows in Figure 1. As already mentioned above, the time interval between the mixing of the reactants and the onset of the critical reaction phase is generally of the order of 1 to 10 seconds. It is therefore necessary to ensure rapid and vigorous mixing of the components and a sufficiently short time of stay of the mixture in the extruder before it enters the kneading zone which is an essential part of the invention.
The subsequent kneading zones (8) and (9) shown in Figure 1, beside the important first kneading zone (7) which prevents the formation of lumps, serve to homogenize the material in the later stage of the reaction. These kneading zones (8) and (9) are, however, of minor importance. They become important when additives are to be mixed with the poly-urethane. The kneading zones described above (7, 8, 9) operateparticularly vigorously if they are kept filled with substance by means of narrow screw zones or kneading zones (14, 15, 16) which convey substance in the opposite direction. The stream of substance which is directed as described above (by screw threading, conveyor kneading elements or hydraulic bias LeA 15,736 -18-pressure) flows over these small elements which act as ob~truc-tions to the fl~w, The reaction in the screw extruder should, if necessary, be controlled by external cooling and/or by pro-viding a greater screw clearance in the rear part of the extruder(seen in the direction of delivery) so as to prevent over-heating of the reaction mixture and reaction product. The temperature of the product should not exceed 280C and preferably not 260C.
If necessary, the melt in the screw extruder can be freed from volatile constituents by degasification in known manner.
After residence times in the screw extruder generally amounting to 0.8 to 4 minutes at temperatures between about 110 and 280C, the reacted melt is discharged at the end of the extruder through a molding tool, preferably an apertured die (17). The elastomeric polyureas extruded from t,he machine may suitably be cooled in known manner by means of cooling rollers, cooling baths or air and size-reduced in commercial granulators.
The products of the process normally do not require any additional after-treatment since by the new process they are produced within a narrow range of times of stay in the machine, under conditions of constant mixing and very exact temperature control and with exclusion of atmospheric moisture. They are therefore very superior in their mechanical and other properties.
The products of the process can be processed thermoplastically or in solution.
To produce a readily soluble, clear granulate which gives rise to solutions which are free from gel particles, the completely reacted or almost completely reacted polyurea melt LeA 15,736 -19-extruded through a perfoxated die at the end of the screw extruder can be cooled in the form of the extruded strands either in water or with compressed air so that it is super-ficially solidified and, when no longer sticky, the strands may be placed in air or compressed air or a vacuum so that the water adhering to it on the outside is evaporated by the inter-nal heat, and the strands may then be cut up into granules.
The water content of the product is then less than 0.05~ by weight. Alternatively, the melt extruded through a perforated plate at the end of the screw may be granulated under water by a rotating knife and then solidified in the water. The granules are then immediately freed from the water adhering to them by means of air in a drier or in a centrifuge.
The products of the process may be dissolved by the usual organic solvents such as esters, ketones, acid amides, aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, alcohols or ethers, used either singly or as mixtuxes.
The products of the process may be used either solvent-free or in the form of solutions for elastic coatings, e.g.
for textiles, leather, split leather or synthetic resins or they may be used as sheet. The possible uses of the products are known per se.
Dyes, or other additives, e.g. mold-release agents, fillers, reinforcements, or thermoplastics may be added to the products in the screw extruder during or after the reaction.
The numerical values given in the examples are parts by weight or percentages by weight unless otherwise indicated.
The self-cleaning two-shaft screw extruder with both screws in the same sense used in the examples was a ZDSK
53 model of Werner & Pfleiderer which had the following dimen-LeA 15,736 -20-sions:
Shaft diameter D = 53 mm; length of shaft = 30 D;
length of kneading zone: 240 mm each; radial clearance:
approximately 0.1 mm; speed of rotation: 200 to 210, but 100 in example 5 and 300 in example 3 per minute; kneading frequency: 10 Hertz, but 15 Hertz in example 3 and 5 Hertz in example 5.
The elements mounted on the shafts were substantially as shown in Figure 1 but the screw delivery zone (10) was only about half as long as indicated in Figure 1. The time of stay in the machine was on an average about 0.8 to 2 min.
Example 1 A) A prepolymer containing 4.5% of free isocyanate groups is prepared from 69.2 parts of an anhydrous linear poly-ester of adipic acid, hexane diol and 2,2-dimethyl propane-diol-(1,3) (neopentyl glycol) with an average molecular weight of 1700 and 20.5 parts of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane by heating to 80~C with stirring under a stream of nitrogen for 3 hours. The prepolymer is stored at 80C under nitrogen until ready for use.
B) The product from A) is taken from a tank where it is stored under nitrogen at 80C and delivered through a gear wheel pump at the rate of 260 parts per minute into the inlet pipe of a two-shaft screw extruder with both shafts rotating in the same sense at 200 revs. per min., and at the same time, l-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane is taken from another tank where it is stored at 30C and delivered into the inlet of the screw extruder by way of a one-cylinder membrane pump at the rate of LeA 15,736 -21-a) 26.3 parts per minute, b) 25~0 parts per minute, c) 24.2 parts per minute, d) 23.2 parts per minute, and e) 22.8 paxts per minute.
The housing of the extruder is heated with a heating medium, and in the case of experiments d) and e) with a cooling medium at the end of the housing, so that the temperatures of the products measured over the whole length of the extruder are roughly as follows:
a) 145-236C, b) 205-242C, c) 200-243C, d) 145-242C, e) 110-240C.
The lowest temperatures are found to be at or shortly before the perforated plate through which the product is extruded. The strands of product delivered from the extruder are cooled in a water bath, freed from the water adhering to it by means of compressed air and size-reduced in a granulator. The softening range of the reaction product shortly after it has been produced is about 120 to 130C. After 18 hours at 110C, the elastomer is dissolved to form a 30 solution in a mixture of 30 parts of toluene, 30 parts of isopropanol and 10 parts of ethylene glycol monoethyl ether.
Clear, pale-yellow solutions with the following viscosities are obtained:
a) 3521 cP at 20C
b) 9170 cP
LeA 15,736 -22-c) 27,820 cP at 20C
d) 56,048 cP "
e) 305,000 cP "
When solution c) is painted on glass plates, freed from solvent at 120C in a vacuum, detached from its substrate under water and then dried, clear films with a tensile strength of 366 kp/cm and elongation on tearing of 430% are obtained.
Example 2 The procedure is the same as in example lB and the following are added per minute to 260 parts of the isocyanate prepolymer from example lA:
a) a mixture of 32.9 parts of 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane and 4.97 parts of ethylene glycol monomethyl ether, b) a mixture of 24.4 parts of 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane and 1.22 parts of ethylene glycol monoethyl ether, c) a mixture of 24.2 parts of 1-arnino-3-aminomethyl-3,5,5-trimethyl cyclohexane and 0.3 parts of ethylene glycol monoethyl ether.
The approximate temperatures of the product measured over the whole length of the extruder are as follows:
a) 170-235C
b) 200-250C
c) 200-240C.
When the products are dissolved in the solvent mixture described in example lB, they give rise to clear, pale-yellow, 30% solutions which have the following vi~cosities tmeasured on LeA 15,736 -23-the day of production of the resins in the screw extruder):
a) 4340 cP ) b) 3590 cP 1 at 20C
c) 2500 cP ) after 18 hours' storage at 110C:
a) 3930 cP) b) 94&~ cP) at 20C
c) 11,120 cP) Example 3 A) The procedure is the same as described in example lA but using 67Q.25 parts of an adipic acid-butanediol polyester with a hydroxyl number of 52 mg of KOH/g, 30.6 parts of a polydimethyl siloxane which contains methylol end groups and has a hydroxyl number of 198 mg KOH/g and 240.6 parts of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane. A prepolymer which contains 6.28~ of free isocyanate groups is obtained.
B) The procedure is the same as described in example lB but 230 parts of the prepolymer described in example 3A and tne following quantities of l-amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane are introduced per minute into the screw extruder:
a) 32.5 parts 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane b) 31.4 parts "
c) 30.8 parts "
d) 29.8 parts "
e) 28.7 parts "
f) 28.1 parts "
~ he approximate product temperatures measured during the reaction are between 130 and 250C. Granulates are obtained which when dissolved to form 30~ solutions in toluene/isopropanol/
LeA 15,736 -24-1063Z9~
ethylene glycol monoethyl ether (20:20:21) form almost clear, pale-yellow solutions which have the following viscosities (determined at 20C) on the day of production:
a) 582 cP
S b) 1,535 cP
c) 7,490 cP
d) 2,980 cP
e) 8,000 cP
f) 2,810 cP.
Example 4 i 200.6 parts per minute of the polyester from example lA heated to 80C, 59.4 parts per minute of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane kept at 30C and 24.2 parts per minute of 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane kept at 30C are delivered from three separate containers into the screw extruder. The approximate product temperatures measured over the whole length of the extruder housing are between 170 and 230C. The granulated reaction product is kept at 110C for 20 hours and then dissolved as described in example lB. The clear, pale-yellow, 30% solution has a viscosity of 24, 380 cP at 20C.
Example 5 A) The procedure is the same as described in example lA but using 920 parts of a hexanediol polycarbonate with an average molecular weight of 2000 and 238.6 parts of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane. An isocyanate prepolymer which contains 3.9% of free isocyanate groups and is liquid at 80C is obtained after 3 hours.
LeA 15,736 -25-106329~
B) The procedure is the same as described in example 1~. 195 parts of the prepolymer described in 5A and the following quantities of 4,4'-diamino-dicyclohexylmethane are used per minute:
a) 20.0 parts b) 19.5 parts c) 18.6 parts d) 17.8 parts e) 17.5 parts.
The product temperatures measured in the screw ex-truder are 200 to 250C. q~he granulated reaction mixture which softens at 145C is kept at 110C for 18 hours and then dissolved in a mixture of toluene, isopropanol and ethylene glycol monoethyl ether (29:20:21). Slightly cloudy 30%
solutions are obtained which have the following viscosities determined at 20C:
a) 9480 cP
b) 11,740 cP
c) 14,040 cP
d) 32,800 cP
e) 5770 cP
These solutions give rise to clear films. The films from solution d is found to have a tensile strength of 376 kp/cm2 and an elongation on tearing of 370~.
Example 6 A) 715 parts of the hexanediol polycarbonate described in example 5A
15.3 parts of N-methyl-N,N-bis-(~-hydroxypropyl)-amino and 252.65 parts of 1-isocyanato-3-isocyanatomethyl-Le~ 15,736 -26-1063Z9~
3,5,5-trimethyl-cyclohexane are reacted together as described in example 1~. A prepolymer with an isocyanate content of 5.10% is obtained after 3 hours' stirring at 80C.
B) 284 parts of the prepolymer described in example 6A are continuously reacted with 26.8 parts of 1,4-diamino-cyclohexane per minute in a screw extruder as described in example lB. Approximate product temperatures of between 115 and 195C are measured over the whole length of the extruder.
The 30% solution obtained by dissolving the product in a mixture of tertiary butanol, toluene and ethylene glycol monomethyl ether acetate (50:37:13) after it has been stored at room temperature for 7 days is cloudy and has a viscosity of 198,000 cP at 20C.
Example 7 36.8 parts of the hexanediol polycarbonate from example 5A are reacted with 9.54 parts of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane as described in example lA.
A prepolymer which contains 4.5% of free isocyanate groups is obtained. 260 parts of the prepolymer per minute and a) 17.1 parts of 1,4-diaminocyclohexane per minute or b) 16.2 parts of 1,4-diaminocyclohexane per minute are continuously fed into the screw extruder under the conditions indicated in example lB. The approximate product temperatures mea~ured in the extruder were LeA 15,736 -27-a) 180 to 220C and b) 150 to 225C.
30% solutions obtained by dissolving the products in a mixture of isopropanol, toluene and ethylene glycol monoethyl ether S (20:29:21) after they have been stored at 80C for 24 hours have viscosities of a~ 208 cP and b) 160 cP
determined at 20C.
Example 8 A prepolymer which contains 4.3% of free isocyanate groups is prepared from 57.7 parts of the adipic acid polyester from example lA and 19.3 parts of 4,4'-diisocyanato-diphenyl-methane as described in example lA.
Prepolymer and l-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane are continuously fed into the screw extruder in proportions by weight of a) 2500 : 242 b) 2500 : 229 c) 2500 : 222 d) 2500 : 218 e) 2500 : 214 and f) 2500 : 209 under the conditions indicated in example lB. The approximate product temperatures measured in the screw extruder are between 145 and 230C, in the case of e and f between 200 and 230C.
The melts delivered from the extruder are cloudy. 30% solutions of the product in a mixture of toluene, isopropanol and ethylene glycol monoethyl ether (29:29:12) are thixotropic.
LeA 15,736 -28-
Among the polythioethers usable are the condensation products of thiodiglycol with itself and/or with other glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or amino alcohols. The products obtained are either polythio mixed ethers, polythioether esters or polythio ether ester amides, depending on the co-component.
Suitable polyacetals include the compounds which can be prepared from glycols such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxy-diphenyldimethylmethane, hexanediol, and formaldehyde. Polyacetals suitable for the purpose of the invention may also be prepared by the polymerization of cyclic acetals.
Suitable polycarbonates with hydroxyl groups include, those which can be prepared by reacting diols such as propane-1,3-diol, butane-1,4-diol and/or hexane-1,6-diol, diethylene glycol, triethylene glycol, tetraethylene glycol and optionally 2,2-bis-(4-hydroxyphenyl)-propane and/or the corresponding hydrogenated compound with phosgene or preferably with diaryl ~eA 15,736 -9-1063Z9l carbonates such as diphenyl carbonate.
Suitable polyester amides and polyamides include the predominantly linear condensates obtained from polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and mixtures thereof.
Polyhydroxyl compounds which already contain urethane or urea groups and modified or unmodified natural polyols such as castor oil, carbohydrates or starch are also suitable.
Products of addition of alkylene oxide to phenol formaldehyde resins or to urea formaldehyde resins may also be used accord-ing to the invention.
Other examples of the many types of compounds which may be used for carrying out the process of the invention have been described in High Polymers, Volume XVI, "Polyurethanes, Chemistry and Technology" by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32-42 and pages 44-54 and Volume II, 1964, pages 5-6 and 198-199 and in Kunststoff-Handbuch, Volume VII, Vieweg-Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages 45-71.
In addition to the aliphatic diamines used according to the invention, up to 95 mol ~, preferably less than 80 mol %
(based on the total quantity of chain-lengthening agents) and most preferably less than 50 mol % of low-molecular weight dialcohols and/or polyalcohols (molecular weight 62 to 500) may be used. Suitable low-molecular weight dialcohols and/or poly-alcohols include ethylene glycol, propylene-1,2- and 1,3-glycol, butylene-1,4- and 2,3-glycol, hexane-1,6-diol, octane-1,8-diol, neopentyl glycol, cyclohexane dimethanol (1,4-bis-hydroxymethyl cyclohexane), 2-methyl-propane-1,3-diol, xylylene glycol, hydroquinone-bis-~-hydroxyethyl ether, glycerol, LeA 15,736 -10-trimethylolpropane, hexane-1,2,6-trio~ butane-1,2,4-triol, trimethylolether and pentaerythritol.
Suitable examples of aromatic diamines which may be used herein include the bisanthranilic acid estersas described in German Offenlegungsschriften 2,040,644 and 2,160,590; 3,5- and 2,4-diaminobenzoic acid esters as described in German Offenlegungsschrift 2,025,900; diamines with ester groups as described in German Offenlegungsschriften 1,803,635; 2,040,650 and 2,160,589; 3,3'-dichloro-4,4'-diamino-diphenylmethane;
tolylene diamine; 4,4'-diaminodiphenylmethane; and 4,4'-diamino-diphenyl disulphide.
Compounds which are monofunctional in their reaction with isocyanates may also be used as so-called "chain-breaking agents" in proportions of 0.01 to 10% by weight, based on the polyurethane solid content. Monofunctional compounds of this kind include monoamines such as butylamine dibutylamine, octylamine, stearylamine, N-methyl stearylamine, pyrrolidine, piperidine and cyclohexylamine and monoalcohols such as butanol 2-ethyl hexanol, octanol, decanol, the various amyl alcohols, cyclohexanol, ethylene glycol monoethyl ether and the like.
As already mentioned above, the average functionality of all the components used for the reaction should not be substantially greater than two in order to ensure that elasto-meric polyurethane ureas which are still fusible or thermo-plastic will be obtained during the reaction in the screwextruder.
The sequence in which the various reactants are reacted with the diisocyanate and/or the polyisocyanate may be varied. The reaction may be carried out by single-stage or multistage processes but it is preferable if the reaction with LeA 15,736 -11-the hydroxyl-containing compound or compounds is carried out either shortly before or during the reaction with the diamines.
The individual reactants may be introduced into the screw extruder at different points. According to one particular vari-ation of the process, an isocyanate prepolymer is first pre-pared in a mixing and/or reaction vessel (e.g. in a tank or in a mixing head, static mixer or mixing nozzle) from the diisocyanate and/or polyisocyanate and the higher-molecular weight compound or compounds containing an average of at least 1.8 Zerewitinoff-active groups in the molecule and optionally lower molecular weight dialcohols and/or polyalcohols and/or aromatic diamines. This prepolymer is then reacted with the diamines with aliphatically bound amino groups used according to the invention in the screw extruder.
A major advantage of the process according to the invention compared with the discontinuous method previously employed is that it may also be carried out as a one-shot process. In a static reaction vessel such as a iank, it is generally not possible to react polyisocyanates, polyols and aliphatic polyamines simultaneously because polyisocyanates and polyamines rapidly react to form ureas which are insoluble in tne reaction mixture, precipitate and result in inhomogeneities in the end product.
The optionallow-molecular weight diols and/or polyols, aromatic diamines and mono-functional chain-breaking agents may first be mixed eitner with the higher-molecular weight compounds which contain Zerewitinoff-active groups`or with the aliphatic diamines or polyisocyanates, or they may be added separately to the reaction mixture.
In another variation of the process according to the invention, higher-molecular weight compounds which contain LeA 15,736 -12-1063Z9l aliphatically bound amino end groups (so-called amino prepolymers) are used as starting materials which are reacted with the di-isocyanates and optionally polyisocyanates in the screw ex-truder, the isocyanate component acting as chain-lengthening agent. Amino prepolymers of this kind may be prepared by reacting diamines and/or polyamines with a subequivalent amount of diisocyanates or by hydrazinolysis of monoaryl carbonates of the polyesters or polyethers described above. A detailed des-cription of the preparation of amino prepolymers which may be used according to the invention may be found in German Offenlegungsschrift 1,694,152 and U.S. Patent 3,625,871.
Although this is not essential for the process accord-ing to the invention, the reaction may also be carried out in the presence of organic solvents which do not react with isocyanate groups and their reactants, such as esters, ethers, hydrocarbons, halogenated hydrocarbons or peralkylated acid amides.
The reaction of isocyanate groups with other reactants may be accelerated with the usual catalysts for isocyanate reactions in quantities of 0.0001 to 5% by weight, preferably 0.0005 to 2~ by weight (based on the polyurethane solid content).
Suitable catalysts include tertiary amines such as triethyl-amine, N-methyl morpholine, N,N,N',N'-tetramethyl-ethylene diamine, 1,4-diazabicyclo-(2,2,2`-octane, N,N-dimethyl benzyl-amine and 2-methyl-imidazole, organic metal compounds such as zinc octoate, tin(II)-octoate, dibutyl tin(IV)-dilaurate, iron acetyl acetonate, titanium tetrabutylate and dioctyl tin(IV) diacetate and bases such as tetraalkyl ammonium hydroxides, sodium hydroxide, sodium phenolate and the like. However, a catalyst is not required.
Other suitable catalysts which may be used according LeA 15,736 -13-1063Z9l to the invention and details concerning the action of the catalysts are described in Kunststoff~andbuch, Volume VII, published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages 96 to 102.
In the process according to the invention, the isocyan~te groups and the Zerewitinoff-active groups, including the primary and secondary aliphatic amino groups, are generally used in stoichiometric proportions. The ratio of isocyanate groups to groups which are reactive with them is generally between 0.80 and 1.3, preferably between 0.90 and 1.10. Deviations from these ratios are, of course, permissible for special purposes.
The molar ratio of higher-molecular weight compounds which contain Zerewitinoff-active groups to the chain-lengthening agents (i.e. the low molecular weight aliphatic diamines and optionally aromatic diamines or low molecular weight diols and/or polyols), is generally between 10:1 and 1:20, preferably between 5:2 and 1:15.
The process according to the invention may be carried out in the presence of the usual lubricants, dyes, pigments and other additives such as fillers and reinforcing substances.
The invention is illustrated in Figures 1 through 7.
Figure 1 represents a two-shaft screw extruder equipped with means for zone-wise heating or cooling of the housing, and alternate kneading zones and self-cleaning screw conveyor zones.
Figures 2 to 6 represent various types of suitable kneading elements.
Figure 7 shows kneading discs arranged in the form of a screw thread and staggered like spiral staircases (in the direction of delivery) at the beginning of the screw shafts.
~ - 14 -LeA 15,736-Ca `' -1063Z9l When carrying out the process according to the invention, the reactants are delivered in known manner, e.g. from gear wheel, piston or membrane pumps. They may be partly mixed before their entry into the screw extruder, as already described above.
The reactants are introduced into a multi-shaft screw extruder either singly or already partly mixed. The extruder used is known per se and is commercially available.
LeA 15,736-Ca - 14a -It may be a self-cleaning, two-shaft screw extruder with both shafts rotating in the same sense (such as, for example, the screw 1 in Figure 1) equipped with means for zonewise heating or cooling of the housing (2-6 in Figure 1), e.g. by means of a liquid heat transfer medium. If the reactants mentioned above are reacted continuously in single-shaft or multi-shaft screw extruders without the particular measures according to the invention, the extruded melt invariably contains gel-like particles or lumps. This may be explained on the grounds that parts of the reaction mixture, which are very sticky during a critical phase of the reaction during which it has a viscosity of about 100 to about 1000 poises, remain too long and stick to the screw shafts and walls of the housing (even in the case of multi-shaft extruders with screws intermeshing with the necessary clearance). These particles which differ from the main mass of the reaction mixture as regards their residence time in the extruder and their reaction history, therefore, also in their properties, subsequently become detached by accident and incorporated in the elastomer. In addition, lumps may occur due to insufficient homogenization before the reaction.
To prevent this formation of lumps, the process accord-ing to the invention is carried out at a relatively high temperature, a temperature above the softening point of the elastomeric polyurea formed in the extruder being employed even at the beginning of the screw, and the melt is subjected to a high velocity gradient (more than about 2000 sec 1 in the clearance between screws and the wall of the housing) while it is still a relatively low viscosity melt in the critical reaction phase defined above (viscosity between about 100 and about 1000 poises) and at the same time, the kneading elements subject this melt to a rhythmic kneading movement at frequencies LeA 15,736 -15-~63291 of 1 to 20 Hertz, preferably 5 to 15 Hertz.
These measures cause the substance to be vigorously mixed in the radial direction so that the reaction proceeds homogeneously and no substance can adhere to the screw shafts and walls of the housing. The reaction is preferably carried out in self-cleaning, two-shaft screw extruders with both shafts rotating in the same sense, and at temperatures between 110 and 280C and with the usual radial clearance in such extruders of 0.05 and 0.6 mm, depending on the size of the screws, and at screw rotations of 70 revs. per min. Thus, for example, the speed of rotation which can successively be employed in such a two-shaft screw extruder in which the screws have an external diameter of 53 mm and a radial clearance of 0.2 mm is 210 revs. per min. which corresponds to a maximum velocity gradient in the sheared product of 2920 sec 1 between the external diameter of the screw and the housing, in other words, calculated in the radial clearance. Suitable kneading elements are, for example, those described in German Patents 813,154 and 940,109 and are also shown in Figures 2-6 which represent prosmatic discs of various geometrical shapes which scrape against each other in every position except for the snall clearance which is mechanically necessary, and which cooperate with the ribs (18, 19 in Figures 2-6) of the housing to exert high shearing and frictional forces on the material which is being mixed. A plurality of such kneading discs stag-gered on the shaft in the circumferential direction amounts to a kneading zone (7, 8, 9 in Figure 1).
Since such a kneading zone generally hinders the flow of substances passing continuously through the extruder housing in the axial direction, it must be preceded by a self-cleaning screw conveyor zone (10, 11, 12 as shown in Figure 1) LeA 15,736- Ca ~ - 16 -1., in which the pressure is built up. The geometry of such aconveyor zone has been described in German Patent 862,668.
For producing polyureas from isocyanates and aliphatic amines, it should be as short as possible so that the time of stay of the reaction mixture in this zone is preferably only about 1 to 10 seconds. The critical stage, in which the substance is particularly sticky and therefore liable to form lumps in the known processes, is in this case situated in the first kneading zone (7), in whicl~ the formation of lumps is prevented under the conditions mentioned above. The highly viscous product of the more advanced reaction (final viscosity up to 3000 poises) can be handled in the screw conveyor zones (10 or 11, 12 and 13) without reduction in quality. The critical reaction stage must be localized in the kneading zone (7) by suitable temperature control of the various zones of the housing (2,3) and, optionally, by the addition of activators to accelerate the reaction.
Kneading discs arranged in the form of a screw thread and staggered like a spiral staircase (in the direction of delivery) at the beginning of the screw shafts as shown in Figure 7 have also been found to be suitable according to the invention. In addition to the desired mixing action in the radial direction, they also have a conveying action in the axial direction so that the screw conveyor zone (10) and kneading zone (7) in Figure 1 may be replaced by a conveying-kneading zone shown in Figure 7.
According to another preferred embodiment of the ïnve-ntion, delïvery of the reacting substance through the kneading zone, which in this case is situated at the beginning of the machine, is achieved by means of a hydraulic bias pressure produced by the delivery pumps of the reactants. The liquid required for this purpose is pumped into the closed LeA 15,736 -17-1063Z9l machine.
It is essential for carrying out the process according to the invention that the di- and/or polyisocyanate and the aliphatic diamine should immediately be vigorously mixed as soon as they are brought together in the screw extruder, preferably a a temperature above the softening point of the product delivered from the extruder.
Owing to the great speed with which they react, the isocyanate component and amino component generally cannot be mixed beforehand but must be introduced separately into the screw extruder, as indicated schematically by the two arrows in Figure 1. As already mentioned above, the time interval between the mixing of the reactants and the onset of the critical reaction phase is generally of the order of 1 to 10 seconds. It is therefore necessary to ensure rapid and vigorous mixing of the components and a sufficiently short time of stay of the mixture in the extruder before it enters the kneading zone which is an essential part of the invention.
The subsequent kneading zones (8) and (9) shown in Figure 1, beside the important first kneading zone (7) which prevents the formation of lumps, serve to homogenize the material in the later stage of the reaction. These kneading zones (8) and (9) are, however, of minor importance. They become important when additives are to be mixed with the poly-urethane. The kneading zones described above (7, 8, 9) operateparticularly vigorously if they are kept filled with substance by means of narrow screw zones or kneading zones (14, 15, 16) which convey substance in the opposite direction. The stream of substance which is directed as described above (by screw threading, conveyor kneading elements or hydraulic bias LeA 15,736 -18-pressure) flows over these small elements which act as ob~truc-tions to the fl~w, The reaction in the screw extruder should, if necessary, be controlled by external cooling and/or by pro-viding a greater screw clearance in the rear part of the extruder(seen in the direction of delivery) so as to prevent over-heating of the reaction mixture and reaction product. The temperature of the product should not exceed 280C and preferably not 260C.
If necessary, the melt in the screw extruder can be freed from volatile constituents by degasification in known manner.
After residence times in the screw extruder generally amounting to 0.8 to 4 minutes at temperatures between about 110 and 280C, the reacted melt is discharged at the end of the extruder through a molding tool, preferably an apertured die (17). The elastomeric polyureas extruded from t,he machine may suitably be cooled in known manner by means of cooling rollers, cooling baths or air and size-reduced in commercial granulators.
The products of the process normally do not require any additional after-treatment since by the new process they are produced within a narrow range of times of stay in the machine, under conditions of constant mixing and very exact temperature control and with exclusion of atmospheric moisture. They are therefore very superior in their mechanical and other properties.
The products of the process can be processed thermoplastically or in solution.
To produce a readily soluble, clear granulate which gives rise to solutions which are free from gel particles, the completely reacted or almost completely reacted polyurea melt LeA 15,736 -19-extruded through a perfoxated die at the end of the screw extruder can be cooled in the form of the extruded strands either in water or with compressed air so that it is super-ficially solidified and, when no longer sticky, the strands may be placed in air or compressed air or a vacuum so that the water adhering to it on the outside is evaporated by the inter-nal heat, and the strands may then be cut up into granules.
The water content of the product is then less than 0.05~ by weight. Alternatively, the melt extruded through a perforated plate at the end of the screw may be granulated under water by a rotating knife and then solidified in the water. The granules are then immediately freed from the water adhering to them by means of air in a drier or in a centrifuge.
The products of the process may be dissolved by the usual organic solvents such as esters, ketones, acid amides, aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, alcohols or ethers, used either singly or as mixtuxes.
The products of the process may be used either solvent-free or in the form of solutions for elastic coatings, e.g.
for textiles, leather, split leather or synthetic resins or they may be used as sheet. The possible uses of the products are known per se.
Dyes, or other additives, e.g. mold-release agents, fillers, reinforcements, or thermoplastics may be added to the products in the screw extruder during or after the reaction.
The numerical values given in the examples are parts by weight or percentages by weight unless otherwise indicated.
The self-cleaning two-shaft screw extruder with both screws in the same sense used in the examples was a ZDSK
53 model of Werner & Pfleiderer which had the following dimen-LeA 15,736 -20-sions:
Shaft diameter D = 53 mm; length of shaft = 30 D;
length of kneading zone: 240 mm each; radial clearance:
approximately 0.1 mm; speed of rotation: 200 to 210, but 100 in example 5 and 300 in example 3 per minute; kneading frequency: 10 Hertz, but 15 Hertz in example 3 and 5 Hertz in example 5.
The elements mounted on the shafts were substantially as shown in Figure 1 but the screw delivery zone (10) was only about half as long as indicated in Figure 1. The time of stay in the machine was on an average about 0.8 to 2 min.
Example 1 A) A prepolymer containing 4.5% of free isocyanate groups is prepared from 69.2 parts of an anhydrous linear poly-ester of adipic acid, hexane diol and 2,2-dimethyl propane-diol-(1,3) (neopentyl glycol) with an average molecular weight of 1700 and 20.5 parts of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane by heating to 80~C with stirring under a stream of nitrogen for 3 hours. The prepolymer is stored at 80C under nitrogen until ready for use.
B) The product from A) is taken from a tank where it is stored under nitrogen at 80C and delivered through a gear wheel pump at the rate of 260 parts per minute into the inlet pipe of a two-shaft screw extruder with both shafts rotating in the same sense at 200 revs. per min., and at the same time, l-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane is taken from another tank where it is stored at 30C and delivered into the inlet of the screw extruder by way of a one-cylinder membrane pump at the rate of LeA 15,736 -21-a) 26.3 parts per minute, b) 25~0 parts per minute, c) 24.2 parts per minute, d) 23.2 parts per minute, and e) 22.8 paxts per minute.
The housing of the extruder is heated with a heating medium, and in the case of experiments d) and e) with a cooling medium at the end of the housing, so that the temperatures of the products measured over the whole length of the extruder are roughly as follows:
a) 145-236C, b) 205-242C, c) 200-243C, d) 145-242C, e) 110-240C.
The lowest temperatures are found to be at or shortly before the perforated plate through which the product is extruded. The strands of product delivered from the extruder are cooled in a water bath, freed from the water adhering to it by means of compressed air and size-reduced in a granulator. The softening range of the reaction product shortly after it has been produced is about 120 to 130C. After 18 hours at 110C, the elastomer is dissolved to form a 30 solution in a mixture of 30 parts of toluene, 30 parts of isopropanol and 10 parts of ethylene glycol monoethyl ether.
Clear, pale-yellow solutions with the following viscosities are obtained:
a) 3521 cP at 20C
b) 9170 cP
LeA 15,736 -22-c) 27,820 cP at 20C
d) 56,048 cP "
e) 305,000 cP "
When solution c) is painted on glass plates, freed from solvent at 120C in a vacuum, detached from its substrate under water and then dried, clear films with a tensile strength of 366 kp/cm and elongation on tearing of 430% are obtained.
Example 2 The procedure is the same as in example lB and the following are added per minute to 260 parts of the isocyanate prepolymer from example lA:
a) a mixture of 32.9 parts of 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane and 4.97 parts of ethylene glycol monomethyl ether, b) a mixture of 24.4 parts of 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane and 1.22 parts of ethylene glycol monoethyl ether, c) a mixture of 24.2 parts of 1-arnino-3-aminomethyl-3,5,5-trimethyl cyclohexane and 0.3 parts of ethylene glycol monoethyl ether.
The approximate temperatures of the product measured over the whole length of the extruder are as follows:
a) 170-235C
b) 200-250C
c) 200-240C.
When the products are dissolved in the solvent mixture described in example lB, they give rise to clear, pale-yellow, 30% solutions which have the following vi~cosities tmeasured on LeA 15,736 -23-the day of production of the resins in the screw extruder):
a) 4340 cP ) b) 3590 cP 1 at 20C
c) 2500 cP ) after 18 hours' storage at 110C:
a) 3930 cP) b) 94&~ cP) at 20C
c) 11,120 cP) Example 3 A) The procedure is the same as described in example lA but using 67Q.25 parts of an adipic acid-butanediol polyester with a hydroxyl number of 52 mg of KOH/g, 30.6 parts of a polydimethyl siloxane which contains methylol end groups and has a hydroxyl number of 198 mg KOH/g and 240.6 parts of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane. A prepolymer which contains 6.28~ of free isocyanate groups is obtained.
B) The procedure is the same as described in example lB but 230 parts of the prepolymer described in example 3A and tne following quantities of l-amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane are introduced per minute into the screw extruder:
a) 32.5 parts 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane b) 31.4 parts "
c) 30.8 parts "
d) 29.8 parts "
e) 28.7 parts "
f) 28.1 parts "
~ he approximate product temperatures measured during the reaction are between 130 and 250C. Granulates are obtained which when dissolved to form 30~ solutions in toluene/isopropanol/
LeA 15,736 -24-1063Z9~
ethylene glycol monoethyl ether (20:20:21) form almost clear, pale-yellow solutions which have the following viscosities (determined at 20C) on the day of production:
a) 582 cP
S b) 1,535 cP
c) 7,490 cP
d) 2,980 cP
e) 8,000 cP
f) 2,810 cP.
Example 4 i 200.6 parts per minute of the polyester from example lA heated to 80C, 59.4 parts per minute of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane kept at 30C and 24.2 parts per minute of 1-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane kept at 30C are delivered from three separate containers into the screw extruder. The approximate product temperatures measured over the whole length of the extruder housing are between 170 and 230C. The granulated reaction product is kept at 110C for 20 hours and then dissolved as described in example lB. The clear, pale-yellow, 30% solution has a viscosity of 24, 380 cP at 20C.
Example 5 A) The procedure is the same as described in example lA but using 920 parts of a hexanediol polycarbonate with an average molecular weight of 2000 and 238.6 parts of l-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane. An isocyanate prepolymer which contains 3.9% of free isocyanate groups and is liquid at 80C is obtained after 3 hours.
LeA 15,736 -25-106329~
B) The procedure is the same as described in example 1~. 195 parts of the prepolymer described in 5A and the following quantities of 4,4'-diamino-dicyclohexylmethane are used per minute:
a) 20.0 parts b) 19.5 parts c) 18.6 parts d) 17.8 parts e) 17.5 parts.
The product temperatures measured in the screw ex-truder are 200 to 250C. q~he granulated reaction mixture which softens at 145C is kept at 110C for 18 hours and then dissolved in a mixture of toluene, isopropanol and ethylene glycol monoethyl ether (29:20:21). Slightly cloudy 30%
solutions are obtained which have the following viscosities determined at 20C:
a) 9480 cP
b) 11,740 cP
c) 14,040 cP
d) 32,800 cP
e) 5770 cP
These solutions give rise to clear films. The films from solution d is found to have a tensile strength of 376 kp/cm2 and an elongation on tearing of 370~.
Example 6 A) 715 parts of the hexanediol polycarbonate described in example 5A
15.3 parts of N-methyl-N,N-bis-(~-hydroxypropyl)-amino and 252.65 parts of 1-isocyanato-3-isocyanatomethyl-Le~ 15,736 -26-1063Z9~
3,5,5-trimethyl-cyclohexane are reacted together as described in example 1~. A prepolymer with an isocyanate content of 5.10% is obtained after 3 hours' stirring at 80C.
B) 284 parts of the prepolymer described in example 6A are continuously reacted with 26.8 parts of 1,4-diamino-cyclohexane per minute in a screw extruder as described in example lB. Approximate product temperatures of between 115 and 195C are measured over the whole length of the extruder.
The 30% solution obtained by dissolving the product in a mixture of tertiary butanol, toluene and ethylene glycol monomethyl ether acetate (50:37:13) after it has been stored at room temperature for 7 days is cloudy and has a viscosity of 198,000 cP at 20C.
Example 7 36.8 parts of the hexanediol polycarbonate from example 5A are reacted with 9.54 parts of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane as described in example lA.
A prepolymer which contains 4.5% of free isocyanate groups is obtained. 260 parts of the prepolymer per minute and a) 17.1 parts of 1,4-diaminocyclohexane per minute or b) 16.2 parts of 1,4-diaminocyclohexane per minute are continuously fed into the screw extruder under the conditions indicated in example lB. The approximate product temperatures mea~ured in the extruder were LeA 15,736 -27-a) 180 to 220C and b) 150 to 225C.
30% solutions obtained by dissolving the products in a mixture of isopropanol, toluene and ethylene glycol monoethyl ether S (20:29:21) after they have been stored at 80C for 24 hours have viscosities of a~ 208 cP and b) 160 cP
determined at 20C.
Example 8 A prepolymer which contains 4.3% of free isocyanate groups is prepared from 57.7 parts of the adipic acid polyester from example lA and 19.3 parts of 4,4'-diisocyanato-diphenyl-methane as described in example lA.
Prepolymer and l-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane are continuously fed into the screw extruder in proportions by weight of a) 2500 : 242 b) 2500 : 229 c) 2500 : 222 d) 2500 : 218 e) 2500 : 214 and f) 2500 : 209 under the conditions indicated in example lB. The approximate product temperatures measured in the screw extruder are between 145 and 230C, in the case of e and f between 200 and 230C.
The melts delivered from the extruder are cloudy. 30% solutions of the product in a mixture of toluene, isopropanol and ethylene glycol monoethyl ether (29:29:12) are thixotropic.
LeA 15,736 -28-
Claims (6)
1. A process for the continuous production of elastomeric polyurethane ureas by reacting diisocyanates with a compound selected from the group consisting of aliphatic primary diamines, cycloaliphatic primary diamines, araliphatic primary diamines, aliphatic secondary diamines, cycloaliphatic secondary diamines and araliphatic secondary diamines in self-cleaning two-shaft screw extruders with both the shafts rotating in the same sense, at temperatures between 110 to 280°C and at a viscosity range during the reaction in the screw extruder of about 0.1 to about 3000 poises, characterized in that for the purpose of obtaining a homogeneous end product free from lumps the critical reaction phase, in which the reaction mixture is very sticky and has a viscosity between about 100 and about 1000 poises, is passed through in a zone of the screw which is situated in the front part of the housing and which contains vigorously mixing knead-ing elements with kneading frequencies of about 1 to about 20 Hertz and in which there is a velocity gradient in the radical clearance between the screw and housing wall of more than about 2000 sec-1.
2. The process according to Claim 1, characterized in that the diisocyanates used are isocyanate-containing prepolymers of monomeric diisocyanates and polyhydroxyl compounds which have molecular weights of 500 to 10,000.
3. The process according to Claim 1 characterized in that the diisocyanates and optionally polyisocyanates and the diamine are fed into the screw extruder at different points.
4. The process according to Claim 1 characterized in that the transport of reactive substance through the kneading zone situated at the beginning of the extruder is effected by a hydraulic bias pressure produced by the feed pumps.
5. The process of Claim 1 wherein polyisocyanates are used in addition to the diisocyanates.
6. The process of Claim 1 wherein compounds which contain an average of at least 1.8 Zerewitinoff-active groups are used in addition to said diamines.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742423764 DE2423764C3 (en) | 1974-05-16 | 1974-05-16 | Process for the continuous production of elastomeric polyurethane ureas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1063291A true CA1063291A (en) | 1979-09-25 |
Family
ID=5915715
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA226,589A Expired CA1063291A (en) | 1974-05-16 | 1975-05-09 | Process for the production of elastomeric polyurethane ureas |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS5546408B2 (en) |
| BE (1) | BE829120A (en) |
| CA (1) | CA1063291A (en) |
| DE (1) | DE2423764C3 (en) |
| DK (1) | DK214175A (en) |
| ES (1) | ES437684A1 (en) |
| FR (1) | FR2271247B1 (en) |
| GB (1) | GB1508317A (en) |
| IE (1) | IE41241B1 (en) |
| IT (1) | IT1035720B (en) |
| LU (1) | LU72469A1 (en) |
| NL (1) | NL170743C (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2610980B2 (en) * | 1976-03-16 | 1978-01-12 | Basf Ag, 6700 Ludwigshafen | PROCESS FOR THE CONTINUOUS MANUFACTURING OF THERMOPLASTIC POLYURETHANE ELASTOMERS |
| DE2842806A1 (en) * | 1978-09-30 | 1980-04-10 | Bayer Ag | METHOD FOR PRODUCING POLYURETHANE ELASTOMERS |
| DE2854386A1 (en) | 1978-12-16 | 1980-07-03 | Bayer Ag | METHOD FOR PRODUCING THERMOPLASTIC CHEMICAL MATERIALS |
| DE2925944A1 (en) | 1979-06-27 | 1981-01-22 | Bayer Ag | METHOD FOR PRODUCING POLYURETHANE UREAS |
| DE3015576A1 (en) * | 1980-04-23 | 1981-10-29 | Bayer Ag, 5090 Leverkusen | METHOD FOR PRODUCING ISOCYANATE POLYADDITION PRODUCTS AND THE USE THEREOF AS A THERMOPLASTIC PRESSING MATERIAL OR AS A REACTIVE FILLER, ESPECIALLY IN A METHOD FOR THE PRODUCTION OF POLYURETHANE PLASTICS |
| JPS6359531A (en) * | 1986-08-29 | 1988-03-15 | 花王株式会社 | Manufacture of polyurethane laminate |
| DE4202973A1 (en) * | 1992-02-03 | 1993-08-05 | Bayer Ag | METHOD FOR THE CONTINUOUS PRODUCTION OF POLYURETHANE AND POLYURETHANE URBAN ELASTOMERS |
| DE4428458A1 (en) | 1994-08-11 | 1996-02-15 | Bayer Ag | Cycloaliphatic thermoplastic polyurethane elastomers |
| DE4437586A1 (en) | 1994-10-20 | 1996-04-25 | Basf Schwarzheide Gmbh | Process for the preparation of thermoplastic polyurethanes |
| DE59905379D1 (en) * | 1998-01-23 | 2003-06-12 | Kloeckner Desma Schuhmaschinen | Use of a device for shot-wise mixing and dispensing of in the cavity of a mold of an injection molding ausreagierenden and curing multi-component plastics |
| DE10221047A1 (en) * | 2002-05-10 | 2003-11-27 | Degussa | Process for the solvent-free, continuous production of polyureas |
| US8094784B2 (en) | 2003-04-25 | 2012-01-10 | Rapiscan Systems, Inc. | X-ray sources |
| US9208988B2 (en) | 2005-10-25 | 2015-12-08 | Rapiscan Systems, Inc. | Graphite backscattered electron shield for use in an X-ray tube |
| GB0812864D0 (en) | 2008-07-15 | 2008-08-20 | Cxr Ltd | Coolign anode |
| DE102005004967A1 (en) * | 2005-02-03 | 2006-08-10 | Basf Ag | Process for the continuous production of thermoplastically processable polyurethane elastomers |
| WO2013030148A1 (en) | 2011-08-29 | 2013-03-07 | Bayer Intellectual Property Gmbh | Hydrophilic thermoplastic polyurethanes and use thereof in medical equipment |
| WO2013083511A1 (en) | 2011-12-06 | 2013-06-13 | Bayer Intellectual Property Gmbh | Tcd alcohol-based thermoplastic polyurethane urea polymers, and the use of same |
| EP3439846A1 (en) | 2016-04-06 | 2019-02-13 | Zzyzx Polymers LLC | Processable polymers and methods of making and using |
-
1974
- 1974-05-16 DE DE19742423764 patent/DE2423764C3/en not_active Expired
-
1975
- 1975-05-09 CA CA226,589A patent/CA1063291A/en not_active Expired
- 1975-05-13 GB GB2008275A patent/GB1508317A/en not_active Expired
- 1975-05-14 LU LU72469A patent/LU72469A1/xx unknown
- 1975-05-14 ES ES437684A patent/ES437684A1/en not_active Expired
- 1975-05-14 IT IT4958675A patent/IT1035720B/en active
- 1975-05-15 NL NL7505741A patent/NL170743C/en not_active IP Right Cessation
- 1975-05-15 DK DK214175A patent/DK214175A/en unknown
- 1975-05-15 IE IE108875A patent/IE41241B1/en unknown
- 1975-05-15 BE BE156388A patent/BE829120A/en not_active IP Right Cessation
- 1975-05-16 FR FR7515489A patent/FR2271247B1/fr not_active Expired
- 1975-05-16 JP JP5755775A patent/JPS5546408B2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| LU72469A1 (en) | 1976-03-17 |
| IT1035720B (en) | 1979-10-20 |
| DE2423764A1 (en) | 1975-11-27 |
| FR2271247B1 (en) | 1980-02-08 |
| ES437684A1 (en) | 1977-02-01 |
| NL170743B (en) | 1982-07-16 |
| DE2423764B2 (en) | 1979-02-22 |
| NL7505741A (en) | 1975-11-18 |
| NL170743C (en) | 1982-12-16 |
| IE41241B1 (en) | 1979-11-21 |
| GB1508317A (en) | 1978-04-19 |
| FR2271247A1 (en) | 1975-12-12 |
| DE2423764C3 (en) | 1979-10-18 |
| DK214175A (en) | 1975-11-17 |
| IE41241L (en) | 1975-11-16 |
| JPS50159590A (en) | 1975-12-24 |
| BE829120A (en) | 1975-11-17 |
| JPS5546408B2 (en) | 1980-11-22 |
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