PT101097A - SYSTEMS FOR OBTAINING RETICULABLE THERMOFIBLE ADHESIVES, PROCESS FOR THEIR PREPARATION AND COLLAGE PROCESS THAT USES THEM - Google Patents

Description

Description of the invention of BOSTIK SA, French, industrial and commercial, established at Route Nationale 19, 77170 Coubert, France, (inventors: Mohamed Moustamsik-Billato and Domi-nique Chiarabini, residing in France), for: "; SYSTEMS FOR OBTAINING RETICULABLE THERMOFUNDABLE ADHESIVES. PROCESS FOR YOUR PREPARATION AND COLLAGE PROCESS USING THEM ".

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to systems for obtaining hot melt adhesives which have the particular feature of having a substantially irreversible cross-linked product after application on the surfaces to be glued, making it infiltrable or difficult to melt. It also relates to the process pitch for the preparation of these systems, as well as to a sizing process using them.

The systems for obtaining crosslinkable thermofractable adhesives according to the present invention have the dual advantage that they can be very easily prepared in industrial plants, namely automated plants (ro bots), such as those in the automotive industry, and can be applied on numerous types of objects produced in a variety of materials such as wood, metals, textile fabrics * or non-woven fabrics, glass, porcelain, ceramics, paper, paper,

concrete and plastics. They have, in particular, excellent adhesive power vis-à-vis non-porous closed substrates such as polystyrene, untreated polyethylene, and untreated polyvinyl chloride, acrylonitrile-butanediene styrene acrylonitrile, poly (methacrylate of methyl), glass and aluminum. It is known from the patent application BP-A-222 795 or a system for obtaining removable hot melt adhesives, characterized in that it comprises (A) a first composition which does not have anhydride groups and contains a) at least one polymer chosen from the thermo-elastic polymers and the synthesis cautchous; b) at least one compound which has at least one group capable of reacting with anhydrous groups; c) at least one accelerating resin; and d) if appropriate, at least one plasticizing agent; (s) a second composition containing a) at least one polymer chosen from the polymorphic polymers and synthetic polymers; b) at least one compound having at least one anhydride group; c) at least one accelerating resin; and d) if applicable, at least one plasticizing agent; and (o) at least one activator of the reaction between the reactive groups of the constituent (Ab) and the anhydride functions of the constituent (Bb).

This system finds an especially advantageous application in the field of book binding. However, in this application area it is still sought to improve the tear strength for the different paper qualities by maintaining a hot melt adhesive system with a softening temperature at least equal to 180øC and a firing temperature at maximum temperature equal to -10 ° C. Thus, in this field, the

2 B

problem to be solved by the present invention is that, by keeping all other properties alike, look for a hot melt adhesive having a tearing force greater than that of the adhesive of EP-A-252 795.

In other applications such as polyester polyester or polyester-to-aluminum bonding in the automotive industry, the adhesive system described in EP-A-252 795 is difficult to use since it has a generally lower breaking strength than the requirements by car manufacturers. A second problem to be solved by the present invention therefore consists in the search for a hot melt adhesive system with a breaking strength of at least 4 MPa, in order to allow the bonding of ροΐχόε ter onto polyester or aluminum.

Adhesive systems according to the present invention are, in particular, systems consisting of two compositions (renamed A and B), one comprising, in particular, epoxy groups and the other having, in particular, groups capable of reacting with the latter after the rings are opened oxirane. These compositions may in each case be melted and melt for relatively long periods of time, compatible with the requirements of an industrial scale, cooled and melted without causing cross-linking. At the time of use, these two compositions are brought into contact in the molten state (intimate mixing or overlapping of one layer on one layer of the other), and the expected crosslinking then takes place under the effect of a rise in temperature.

This mechanism of cross-linking between the open epoxy groups and the other reactive groups is known as such, but has never been applied in this way to industrial collagens.

The systems according to the present invention do not require the addition of exterior agents to crosslink, since compositions A and B contain all the ingredients necessary for cross-linking.

Accordingly, the present invention relates first to a system for obtaining crosslinkable hot melt adhesives, characterized in that it comprises (A) a first composition which does not have epoxy groups and contains a) at least one polymer chosen from the polymers have moelastic and the cautehous of synthesis; b) at least one compound having at least one group capable of reacting with epoxy groups; c) at least one accelerating resin; and d) if applicable, at least one plasticizing agent or a wax; (B) a second composition containing a) if appropriate, at least one polymer selected from the thermoelastic polymers and the synthesis caouthetics; b) at least one compound having at least one epoxy group; c) at least one accelerating resin; and d) if appropriate, at least one plasticizing agent or a wax; and (C) if appropriate, at least one activator of the reaction between the reactive groups of the constituent (Ab) and the epoxy functions of the constituent (Bb).

Preferably the molar ratio of the reactive groups of the constituent (Ab) to the epoxy groups of the constituent (Bb) is at least 1.

In addition, for each 100 parts by weight of the combination (â), it preferably comprises: - 10 to 60 parts by weight of the constituent (Aa) - 3 to 15 parts by weight of the constituent (Ab) and - 10 to 60 parts by weight of the constituent (Ac) - 0 to 100 parts by weight of the constituent (Ad).

Likewise, for each 100 parts by weight of the combination (B), it comprises, in particular, 4 to 20 parts by weight of the constituent (Ba) -20 to 60 parts by weight of the constituent (Bb) - 10 to 60 parts by weight of the constituent (Bc) and - 0 to 4 parts by weight of the constituent (Bd).

The thermoelastic polymers falling within the definition of the constituents (Aa) and Ba) are preferably chosen from the group of copolymers of ethylene and vinyl acetate or alkyl acrylate having a high content (about 20-50% by weight) of acetate or acrylate, and of high molecular weight (about 5000 to 30,000). Synthetic caffeines which form part of the definition of constituents (Aa) and (Ba) are preferably chosen from styrene / butadiene or styrene / isoprene copolymers with linear or star block.

According to one of the embodiments of the system for obtaining hot melt adhesives according to the present invention, the compound (Aa) comprises at least one amino group. By way of example of such a compound (Ab) may be mentioned a polyamide with free amino functions.

Usable polyamides are in particular polyamides obtained from (a) 35-49.5% per mole of dimer fatty acid, (b) 0.5-15% per mole of monomer fatty acid having a chain length (c) 2 - 35% per mole of polyetheramine of the general formula in which x represents 8 to 8, especially 8 to 4θ, ; R 2 and R 3 represent identical or different, hydroformyl and / or cycloaliphatic hydrocarbon radicals; and R represents an optionally branched aliphatic hydrocarbon radical having 1-6 carbon atoms; and (d) 15-48% per mole of aliphatic diamine having 2-40 carbon atoms in the carbon skeleton, the dimer fatty acids may be substituted up to 2/3 by aliphatic dicarboxylic acids with 4-12 atoms of carbon; and polyamides obtained from (a) 20-49.5% per mole of dimer fatty acids,

(b) 0.5-15% per mole of monomeric fatty acids having a chain length of 12 to 22 carbon atoms, and (c) up to 20-5% per mole of an amine having at least two primary amino groups and with 2-40 carbon atoms in the carbon skeleton, the dimer fatty acids being substituted up to 2/3 by aliphatic dicarboxylic acids having 4-12 carbon atoms. These polyamides preferably have acid end groups, their acid number being 1 to 50, preferably 2 to 30, and especially 4 to 12. They may also have amino end groups, their amine number being In the second example of compound (Ab) there may also be mentioned the aminoalkyl imidazolidones of the formula: ## STR1 ## wherein R 1, R 2, R 3,

0 N

H wherein n is 1-20. The compound (Bb) is in particular a polymer having epoxy groups, in particular glycidyl group. By way of example, there may be mentioned epoxidized resins having a functionality, defined as the number of epoxy functions per molecule, at least equal to 2, such as bis-phenol A diglycidyl ether, butadiene diepoxide, 4-epoxycyclohexane-carb < / RTI > (1,2-epoxyethyl) diphenyl ether, 4,4'-epoxycyclohexylmethyl xylate, vinylcyclohexane dioxide, 4,4 '-di (1,2-epoxyethyl) diphenyl ether, 4,4' - (1,2-epoxyethyl) 2-bis (3,4-epoxycyclohexyl) propane, diglycidyl ether of resorcinol, diglycidyl ether of floroglucinol, bis (2,3-epoxycyclopentyl ether), 2- (3,4-epoxy) cyclohexane-5,5- spiro (3,4-epoxy) cyclohexane-m-dioxane adipate, bis (394-epoxy-6-methylcyclohexyl) adipate, N, Nm- (phenylene-bis-4,5-epoxy- 2-cyclohexane dicarboxamide), a diepoxy compound having a hydantoin ring, etc. Such resins may be repre- = 6 =

in which R represents a group of the formula -CHO-O-R-O-CH 2, in which R 2 represents a bivalent group selected from the group consisting of alkylene groups having 2-12 carbon atoms and comprising at least one substituted or unsubstituted aliphatic or aromatic ring. There can thus be used tri-epoxidized or tetra epoxidized resins such as eg, p-aminophenol triglyceride ether, polyaryl-glycidyl ethers, 1,3,5-tri (1,2-epoxy) benzene, 2,2 Tetraglyloxytetraphenyl ethane, phenol-formaldehyde resin of the novolike type, triglycidyl ether of glycerol, trimethylol propane triglycidyl ether and tetraglycidyl-4,4 ' '-diaminodiphenylmethane.

This polymer (Bb) may also have, in addition to the epoche groups such as radicals derived from a glycidyl monomer, radicals derived from at least one alkene and, if appropriate, radicals derived from at least one comonomer chosen from between C1-C12 alkyl acrylates and methacrylates. Such copolymers can be obtained either by direct copolymerization of the monomers according to patents FR-A-1 569 OOk and Fr-A-2 130 279 or by introduction of the glycidyl monomer into an alkene homopolymer or a co- ethylene / ethyl acrylate polymer such as distethyl, inter alia, by GALUCCI et al. J. Appl. Polym. Know. 27 (2), pp. ^ 25-37 (1982). In the context of the present invention, it is preferred that such a polymer (Bb) contains approx. 5-20% by weight of glycidyl monomer. As examples of glycidyl monomers there may be mentioned glycidyl acrylate and methacrylate, as well as those of the general formula:

R- \

I / = 7 =

in which X represents an oxygen or sulfur atom, the NH radical, an NR radical in which R represents an alkyl group having 1-12 carbon atoms, or an oxy-alkylene radical -O- (CEL) in which n represents approx. 3-16, represents a hydrogen atom, or an alkyl radical having 1-5 carbon atoms, and R3 represents a hydrocarbon chain having 2-20 carbon atoms selected from the straight or branched chain alkyl groups, cyclo -alkyl or hetero-cycloalkyl, and alkyl-aryl, said hydrocarbon chain having an oxirane group in the chain, or at the terminus of the chain in the case of alkyl or alkylaryl groups, or an exo oxirane group cyclic or endo-cyclic in the case of mono or polycyclic cycloalkyl or hetero-cycloalkyl groups.

Accelerating resins (Ac) and (Bc) are selected from among poly-terpenes, if appropriate funnicized with novolaks, colophanes and esters of colophane and their hydrogenated derivatives, as well as petroleum resins. The petroleum resins usable in the systems according to the present invention are resins prepared from hydrocarbon fractions from the naphtha vapor cracker, such as aromatic fractions containing at least one aromatic alkenyl monomer, aliphatic fractions containing a 3- 6-carbon atoms, such as cyclopentadiene and its derivatives, and cyclohexadiene, or terpene fractions such as turpentine essences. As examples of the alkenyl aromatic groups which may be present in the constitution of these resins may be groups derived from styrene, doc-methyl styrene, indene, vinyl toluene, methyl indenes, N-methyl styrene, and para-tert-butyl styrene. As examples of terpenic groups which may enter into the constitution of these resins, there may be included groups, preferably mono-unsaturated, mono-unsaturated cyclic terpenes derived from cyclic terpenes such as 1-p-methene and tetramethyl-cyclohexene, and mono-unsaturated bicyclics, such as pinenes, carenes, limonene,. 4 (10) -tuben, 5-isopropylbicyclo [3.1.0] hex-2-ene, 4-methylene-

2-norbornene and camphene, as well as certain bi-unsaturated mono-cyclic terpenes such as mentadienes. Examples of resins which can be used in the context of the present invention are described in EP-A-Oil 393, EP-A-132 291, EP-A-233 074 FR-A-2 659 972.

The plasticizing agents (Ad) and (Bd) are selected from among, on the one hand, semi-aliphatic oils, the very low molecular weight polyisobutylene, and the aromatic, naphthenic or paraffinic petroleum oils, the alkyl benzenes, and on the other hand, from among the esters derived from saturated organic acids such as phthalates, adipates, sebases and alkyl azelates. Examples of the latter are diethyl, dibutyl, di-cyclohexyl, diethylhexyl, di-octyl, di-decyl, butyl-ethylhexyl, dibutyl, di-octyl, di-isooctyl adipates , di-butyl, di-octyl, di-isooctyl, di-octyl and di-isooctyl azelates. Plasticizers (Ad) and (Bd), the very low molecular weight ethylene-vinyl acetate copolymers (in the range of 1000-1500) may also be referred to as an example of such a copolymer which contains 28% by weight of vinyl acetate. f

The waxes (Ad) and (Bd) are selected among the waxes of low molecular weight polyethylene (generally less than 5000) and paraffins. The activator (C) is chosen in particular from among the tertiary amines, such as dimethylparatholuidine, adamethyl laurylamine, N-butylmorpholine, α, α-dimethylcyclohexylamine, benzyl dimethyl amine, pyridine, dimethylamino-β-pyridine, methyl-1-imidazole, tetramethyl-didrazine, N, N-dimethyl-piperazine, Î ±, Î ±, Î ±, Î'-tetramethyl -1,6-hexanediamine; phosphines such as triphenyl phosphine and aryl phosphonium halides or alkyl phosphonium such as ethyl triphenyl phosphoenium iodide; and tertiary amides of fatty acids, such as the tertiary amides of soybean fatty acids.

On the other hand, at least one of the compositions (A) or (b) may contain up to 10 parts by weight, for 100 parts. of said composition, of at least one adjuvant such as

wax or paraffin, such as polyethylene wax.

Likewise, at least one of the compositions (a) or (b) may contain up to 5 parts by weight, for 100 parts of said composition, of at least one mineral filler, selected among other things from silica, aluminum, silicates, alumina and silico-aluminates and talc.

Also, at least one of the compositions (â-) or (B) may contain up to 1 part by weight, for 100 parts of said composition, of at least one anti-oxidant agent selected from among the 2,2-di- bis-hydroxy-anisol, 2,2'-thio diethyl bis-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tetrakis (methylene- 2,4-bis-N-octylthio-6- (4-hydroxy-3 > 5-di-tert-butyl-4'-hydroxyphenyl) -propionate- di-tert-butylanilino) -1,3,5-triazine, 3 g of di-tert-butyl 5-hydroxy-propyl-3-propionate and 3,5-di-tert-butyl- The present invention also relates to systems as defined above, in which, when present, the activator (C) is at least partially incorporated in the composition (a) and / or in the The activator (c) may preferably be fully incorporated into the composition (a) and / or the composition (B), so as to form a two component composition es, such as in cases where not present.

According to one of the preferred embodiments, the system of two compositions further comprises a thermoplastic film chemically inert to each of the two compositions, and having on each of its faces a layer of one of said compositions. The inert film will consist of polyethylene or polypropylene, or an ethylene / alkyl acrylate or ethylene / vinyl acrylate copolymer. The present invention further relates to a process for the preparation of a system of two compositions as defined above. The process is characterized in that the constituents of the composition (A) and the constituents of the composition (b) at a temperature sufficient to obtain 10 Λ

(c) to at least one of said compositions (a) and (b) in the presence of a homogeneous liquid, and each of said two liquid mixtures being cooled by incorporating, if appropriate, the activator

Preferably, the constituents of each of compositions (a) and (b) are blended at a temperature at least 10 ° C higher than the softening point of said composition, eg, from 120 ° C to 170 ° C. The temperature at which if desired, the activator (c), is in particular comprised between 120 ° C and 170 ° C.

In cases where the system of two compositions further comprises film in thermoplastic matter, the process is indicated comprises, after the preparation of the two compositions, a step which consists in the application of one of them on one side of said film and the other on the other face. The application of one of the compositions on one of the faces of the film can be done by coextrusion or by wicking, for example in a cylinder or by means of a flat die. The present invention also comprises a process for the gluing of two objects, characterized in that each of the compositions of the two-composition system defined above is brought to a temperature of between 120ø and 220øC, and then - or to mix intimately at this temperature, and then to apply the resulting hotmelt adhesive to at least one of the objects to be glued, and finally to apply one of the objects to be glued against the other - or to separately apply the two compositions either one the other on one of the objects to be glued, or one on one of the objects to be glued and the other on the other object to be glued, and finally to apply said objects against each other.

It is sometimes desirable, after applying the two objects one against the other, to heat the glued objects for a period of time sufficient to complete the cross-linking. The present invention also relates to a process for the gluing of two articles using a system comprising a film of thermoplastic material, characterized in that 11 =

the two objects are glued together by means of a film, and then the assembly is brought to a temperature above the melting point of the thermoplastic film, and sufficient to allow the migration of one of the compounds (Ab) and (Bb) against the other , causing it to come into contact and crosslinking the system.

The following examples are given by way of illustration and not limitation of the present invention. EXAMPLE 1

First, to prepare at a temperature of 170 ° C a composition (a) comprising: - 9.5 parts by weight of a polyamide having free amino functions, having a viscosity of 26 cps at 25 ° C and having an ami index of 400 mg KOH / g, sold by the company CRAY VALLEY PRODUCTS under the designation VERSAMIDB 140, - 40 parts by weight of an ethylene / vinyl acetate copolymer marketed by DU PONT DE NEMOURS under the designation ELVAX 210, 30 parts by weight of an accelerating resin marketed by BERVIK CHEMIE under the designation BBVILITE 6285, - 20 parts by weight of an accelerating resin marketed by the company CRAY VALLEY SA under the designation N0RS0LENER 1090, and - 0.5 parts by weight of a anti-oxidant marketed by CIBA-GEIGY under the designation IRGANOX 1010.

On the other hand, preparing at a temperature of 170 ° C a composition (b) comprising: - parts by weight of an ethylene / ethylene acrylate / glycidyl methacrylate terpolymer having a melt flow index of 4 dg / min (measured from according to ASTM D-1238) and comprising 7% by weight of methacrylate marketed by the company ATOCHEM under the designation L0TADERR HX 8660,

R 20 parts by weight of NORSOLENE 1090 accelerating resin, 20 parts by weight of an accelerating resin sold by the company EXXON CHEMICAL under the designation ESCOREZ114401. - 19,5 parts by weight of tin wax marketed by the company | ALLIED CORPORATION under the designation AC 400, and 12 *

0.5 parts by weight of the anti-oxidant IRGANOX 1010. At 175Â ° C, the composition prepared first has a viscosity of 3000 cps and a viscosity of 15,000 cps is prepared secondly.

For the two composition system obtained by equiponderal mixing of the two compositions described above, at 170Â ° C for 1 minute in a static mixer, the following properties were determined. - softening temperature > 140 ° C after 30 hours (in accordance with standard NFT 76 106) - breaking strength (according to standard NFT 76 107) and 2 MPa - strength of (" coat " (according to NFT 76 112): EXAMPLE 2

By the same procedure as in Example 1, a first composition (a) is prepared comprising: - 5.5 parts by weight of VERSAMIDE 140,

- parts by weight of an ELVAX 210 ethylene / acetate copolymer, - 30 parts by weight of BEVILITE 6285 accelerating resin,

R 20 parts by weight of NORSOLENE 1090 accelerating resin, 4 parts by weight of aminoethyl imidazolidone, and 0.5 parts by weight of the anti-oxidant IRGANOX 1010.

This composition (a) has a viscosity of 3900 cps at 175 ° C.

Following the above standards, the following properties are determined for the two composition system obtained by equiponderal mixing of composition (a) and composition (b) of Example 1. - softening temperature (according to NFT standard 76 1θ6) 113 ° C past k days - breaking resistance (according to NFT 76 107): l, k MPa • - strength of (" coat " ) (according to NFT 76 112):! ktk N * * 13 *

EXAMPLE 3

By the same process as in Example 1, a first composition (a) is prepared comprising: - 11.5 parts by weight of VERSAMIDE 110, - 50 parts by weight of an ethylene / vinyl acetate copolymer sold by DU PONT DE NEMOURS under the designation ELVAX 2040, - 10 parts by weight of BEVILITE 6285 accelerating resin,

R-28 parts by weight of NORSOLENE 1090 accelerating resin, and - 0.5 parts by weight of the anti-oxidant IRGANOX 1010,

This composition (a) has a viscosity of 30,800 cps at 175 ° C.

On the other hand, a composition (b) is prepared containing: - 40 parts by weight of an epoxy resin, solid at room temperature, sold by DOW CHEMICAL under the reference DER 662, with the formula: -CHr CI-I, 011 • 0-Ο "σΟ0" σΗ2-0Η-0Η, ΟΠ

3 parts by weight of ESCGREZ1 * 4401 accelerating resin, - 19.5 parts by weight of AC 400 wax, and - 10 parts by weight of the ethylene / acetate copolymer ELVAX 210,

R-20 parts by weight of NORSOLENE 1090 accelerating resin, and - 0.5 parts by weight of the anti-oxidant XRGANOX 1010.

This composition (b) has a viscosity of

1250 cps at 175 C *

For the two-compartment system obtained by equiponderal mixing of the two compositions (A) and (B) described above, at 150Â ° C for 1 minute in a static mixer, the following property was determined. - shear strength (according to NFT 76 107, aluminum support) · 5 · 5 MPA · s 15 s

Claims (1)

A system for obtaining crosslinkable hot melt adhesives, characterized in that it comprises (A) a first composition which does not have epoxy groups and contains (a) at least one polymer selected from thermoelastic polymers and synthetic polyolefins; (b) at least one compound having at least one group capable of reacting with epoxy groups; and (c) at least one accelerating resin; and (d) if appropriate, at least one plasticizing agent or a wax; (B) a second composition containing; (a) where applicable, at least one polymer selected from thermoelastic polymers and synthetic polymers; (b) at least one compound having at least one epoxy group; (c) at least one accelerating resin; and (d) if appropriate, at least one plasticizing agent or a wax; and (C) if appropriate, at least one activator of the reaction between the reactive groups of the constituent (Ab) and the epoxy functions of the constituent (Bb) " A system according to claim 1, characterized in that the molar ratio of the reactive groups of the constituent (Ab) to the epoxy groups of the constituent (Bb) is at least equal to 1. A system according to any one of claims - = 16 = (A) 10 to 60 parts by weight of the constituent (Aa) - 3 to 15 parts by weight of the constituent (Ab) -10 to 60 parts by weight of the constituent (Ac) and - 0 to 40 parts by weight of the constituent (Ad). The system of any one of claims 1 to 3, wherein in each 100 parts by weight of the composition (b) (Bb) - 20 to 60 parts by weight of the constituent (Bd) - 10 to 60 parts by weight of the constituent (Bc) and - 0 to 40 parts by weight of the constituent (Bd) . 5. A system as claimed in any one of claims 1 to 4, wherein the compound (Ab) has at least one amino group. 6. A system as claimed in claim 5, wherein the compound (Ab) is chosen from free amino functional polyamides and aminoalkylimidazolidones. A system according to claim 1, characterized in that the compound (Bb) is selected from the co-polymers of at least one alkene with at least one unsaturated monomer containing an epoxy group, and the resins epoxy derivatives having a functionality at least equal to 2. The system of claim 1, further comprising a. film of thermoplastic material chemically inert to each of the two compositions, and having on each of its faces a layer of one of said compositions. 9. A process for the gluing of two articles, characterized in that each of the compositions of the system according to claim 1 is carried out at a temperature of from 120ø to 220øC, and then - or intimately mixed at this temperature, and then applying the resulting hotmelt adhesive to at least one of the objects to be glued, and finally applying one of the objects to be glued against the other; - or if the two compositions are applied separately one after the other on one of the objects to be glued, or one on one of the objects to be glued and the other on the other object to be glued, and finally if said objects are applied one against the other. - 10 & 2. A method for gluing two objects using a system according to claim 8, characterized in that the two objects are glued together by means of a film, and then the assembly is brought to a temperature above the melting point of the film and sufficient to allow the migration of one of the compounds (Ab) and (Bb) against the other, causing the cross-linking of the system to come into contact. The applicant claims the priority of the French application filed on 29 November 1991 'under serial number 91-1770' Lisbon, 27 November 1992 18.