WO1994004576A1 - Reactive hot-melt adhesive for joining amorphous or waterproof materials - Google Patents

Abstract

The hot-melt adhesive comprises: (A) a first component containing essentially no water or water-containing substance, and comprising at least one primary diamine having 10 to 100 carbon atoms and at least one organic compound having simultaneously a primary amine function and a hydrolysable silane function, and (B) a second component containing essentially no water or water-containing substance, and comprising an organic compound having functions capable of reacting with the primary amine functions of the diamine of components (A) and with the primary amine functions of the organic compound of component (A), releasing water during said reaction. Application in joining amorphous or waterproof materials.

Description

REAGENT THERMAL FUSE ADHESIVE FOR THE ASSEMBLY OF AMORPHOUS OR WATERPROOF SUBSTRATES.

The present invention relates to a reactive hot-melt adhesive, its preparation process and its use for the assembly of amorphous or waterproof supports.

We already know from US-A-4,913,969 a process for gluing a substrate impermeable to water vapor by means of a hot-melt material which undergoes post-crosslinking in contact with moisture, said process consisting in : (1) applying a suspension or solution of an activating material in a liquid on at least one surface of the substrate to be bonded, the activating material being a substance which releases water fixed chemically or by absorption at the application temperature hot-melt material; (2) remove the liquid, and

(3) applying the hot-melt material to said surface of the substrate.

The activator material which can be used according to this process can be a zeolite, an oxide, hydroxide or salt containing water of crystallization of an alkali, alkaline earth metal or of a metal from groups III A, IB, II B, III B, IV B, VB, VI B, VII or VIII of the

Periodic classification, or alternatively a hydrophilic polymer containing fixed water, chosen from cellulose and starch derivatives, polyacrylamide and polyvinylpyrrolidone. The hot-melt materials which can be used according to this process are in particular thermoplastic polymers containing isocyanate and / or silane and / or siloxane end groups, and preferably polyamides terminated by trialkoxysilane groups.

The shear breaking strength of aluminum samples bonded according to this process, determined according to the standard

DIN 53 283, varies between 0.7 and 2.3 N / mm ² at 100 ° C.

The disadvantages of this process lie in the need for a liquid which must be eliminated in the second stage, this liquid being either water or an organic solvent, alcohol or ketone, the use of which is not recommended for the protection of the environment. To solve these problems, the present invention provides a hot-melt adhesive capable of assembling not only supports impermeable to water vapor, but also amorphous supports, and comprising no organic solvent nor the need to introduce water, such an adhesive therefore making a particular contribution to environmental protection while avoiding the technical complications of an addition of water which must then be eliminated during the process of assembling the supports.

To achieve these objectives, the present invention provides a hot-melt adhesive comprising at least two components capable of reacting with each other, characterized in that it comprises:

(A) a first component not essentially containing water or a substance containing water, and comprising at least one primary diamine having from 10 to 100 carbon atoms approximately and at least one organic compound having simultaneously a primary amine function and a hydrolyzable silane function, and

(B) a second component essentially containing no water or a substance containing water, and comprising an organic compound having functions capable of reacting with the primary amine functions of the diamine of component (A) and with the functions primary amine of the organic compound of component (A) by releasing water during said reaction. By "essentially not containing water or a substance containing water" is meant that the constituents of components (A) and (B) do not contain water or aqueous substance in proportions or concentrations exceeding 1 'state of residual traces inherent in their manufacturing processes, the generally acceptable limits for the adhesives according to the invention being not more than 600 ppm and preferably not more than 200 ppm relative to the weight of said constituents.

Component (A) present in the adhesive according to the invention necessarily comprises at least two organic compounds, one of which necessarily comprises two primary amine functions

-NH ₂ and the other of which must include an amine function primary -NH ₂ and a hydrolyzable silane function. The primary diamine present in component (A) optionally carries other functions, provided that these functions are not reactive with the functions of the organic compound of component (B), such as for example amide functions. Such polyamides with free primary amino functions are especially obtained from (a) 35 to 49.5% by mole of dimeric fatty acid, (b) 0.5 to 15% by mole of monomeric fatty acid of a chain length from 12 to 22 carbon atoms, (c) 2 to 35 mol% of polyetheramine of general formula: H ₂ N - Ri - O - (RO) _x - R ₂ - NH ₂ in which x represents a number between 8 and 80, in particular between 8 and 40; Ri and R ₂ represent hydrocarbon residues, identical or different, aliphatic and / or cycloaliphatic; and R represents an optionally branched aliphatic hydrocarbon residue having 1 to 6 carbon atoms, and (d) 15 to 48 mol% of aliphatic diamine containing 2 to 40 carbon atoms in the carbon skeleton, the dimer fatty acids being able to be replaced up to 2/3 by aliphatic dicarboxylic acids having 4 to 12 carbon atoms; and polyamides obtained from (a) 20 to 49.5% by mole of dimeric fatty acids, (b) 0.5 to 15% by mole of monomeric fatty acids with a chain length of 12 to 22 carbon atoms; and (c) up to 20 to 55 mol% of an amine carrying at least two primary amino groups and having 2 to 40 carbon atoms in the carbon skeleton, the dimer fatty acids being able to be replaced up to 2/3 with aliphatic dicarboxylic acids having 4 to 12 carbon atoms. These polyamides advantageously have primary amine end groups, their amine index ranging from 2 to 15, in particular from 4 to 10. For the ease of use of component (A), it is preferable that the primary diamine occurs in the form of a liquid resin and more particularly of a relatively viscous liquid. As examples of organic compounds with dual functionality primary amine and silane necessarily present in component (A), mention may in particular be made of those of formula:

(RO) ₃ Si (CH ₂ ) _m - A - (CH ₂ ) _n - NH ₂ (I) in which:

R is a hydrocarbon radical, preferably a linear or branched alkyl radical having from 1 to 4 carbon atoms, such as in particular the methyl radical,

- m and n are integers each ranging from 1 to 6, and - A is chosen from the groups -NH- and -CH ₂ -.

N - [3 - (trimethoxysilyl) propyl] ethylene diamine constitutes a representative example of such compounds.

Component (A) present in the adhesive according to the invention can also comprise: - at least one polymer (Aa) chosen from thermoelastic polymers and synthetic rubbers, as defined below;

- at least one tackifying resin (Ab) as defined below;

- at least one antioxidant. Per 100 parts by weight of component (A), this preferably comprises:

- from 2.5 to 9 parts approximately by weight of primary diamine,

- from 1.5 to 4.5 parts approximately by weight of organic compound with hydrolyzable silane function, - from 30 to 60 parts approximately by weight of polymer (Aa),

- from 25 to 45 parts approximately by weight of tackifying resin (Ab), and

- from 0 to 3 parts approximately by weight of antioxidant.

Component (B) present in the adhesive according to the invention necessarily comprises an organic compound capable of reacting with the primary diamine and with the organic compound of component (A) while releasing water during said reaction. To this end, said organic compound of component (B) has reactive functions such as carboxylic acid functions or, preferably, carboxylic anhydride functions. Indeed, carboxylic acid functions will be able to react with the primary amine functions of the primary diamine and of the compound. organic component (A) to form a product comprising amide functions while releasing water. Carboxylic anhydride functions will be able to react with the primary amine functions of the primary diamine and of the organic compound (A) to form a product comprising imide functions while liberating water. The water released during this reaction will itself be capable of hydrolyzing the silane function of the organic compound of component (A) by releasing, for example in the case of a compound of formula (I), an alcohol ROH. For the ease of carrying out the reaction between the components (A) and (B), it is desirable that at the reaction temperature the component (B) is in the liquid state. This is why it is advantageous for its reactive functions - for example carboxylic acid or anhydride - to be distributed along a polymer chain, said polymer then being used in the molten state and kept in fusion for a relatively long time compatible with the requirements of an industrial scale implementation, cooled and remelted without causing crosslinking.

This polymer may also contain, in addition to units derived from an anhydride or carboxylic acid, units derived from at least one alkene and, where appropriate, units derived from at least one comonomer, chosen in particular from acrylates and methacrylates of C 1 -C ₂ alkyl. Such copolymers can be obtained either by direct copolymerization of all the monomers, or by grafting the anhydride on a (co) polymer of the other monomers (alkene; (meth) acrylate). In the case of direct copolymerization, the anhydride content of the copolymer is generally less than or equal to 3% by mole. In the case of grafting, the anhydride content of the copolymer may reach up to 20% by mole.

As examples of reactive functions present in the organic compound of component (B), mention may in particular be made of units derived from an unsaturated dicarboxylic acid anhydride such as maleic, itaconic, phthalic anhydride or else from an unsaturated carboxylic acid such than acrylic or methacrylic acid. Preferably, as the organic compound of component (B), a terpolymer with a melt index of between 2 and 500 dg / min is chosen. comprising about 83-96% by moles of units derived from ethylene, from 4 to 15% by moles of units derived from an acrylate or methacrylate alkyl - Cι ₂ and from 0.3 to 3 approximately mole% of units derived from maleic anhydride, of molecular weight (number average) of between approximately 5,000 and 100,000 and preferably between 15,000 and 50,000. More preferably still, the organic compound of component (B ) is present in the adhesive according to the invention in such proportion, relative to the primary diamine and to the organic compound of the component (A), that the molar ratio of the reactive functions of the component (B) to the primary amine functions present in the component (A) is between 0.6 and 1.4 approximately.

Component (B) present in the adhesive according to the invention can also comprise:

- at least one polymer (Ba) chosen from thermoelastic polymers and synthetic rubbers, as defined below;

- at least one tackifying resin (Bb) as defined below, and

- at least one antioxidant.

Per 100 parts by weight of component (B), this preferably comprises: - from 20 to 50 parts approximately by weight of organic compound capable of reacting with the primary diamine and with the organic compound of component (A) while liberating from water during said reaction,

- from 8 to 15 parts approximately by weight of polymer (Ba),

- from 15 to 40 parts approximately by weight of tackifying resin (Bb), and - from 0 to 3 parts approximately by weight of antioxidant.

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 of high-strength alkyl acrylate (approximately 20 to 50% by weight) in acetate or acrylate and of high molecular weight (approximately 5,000 to 30,000). The synthetic rubbers falling within the definition of the constituents (Aa) and (Ba) are preferably chosen from copolymers with linear or star blocks, styrene / butadiene, or styrene / isoprene. The antioxidant which may be present in component (A) and / or in component (B) of the adhesive according to the invention can be chosen in particular from 2,6-ditertiobutylparacresol, bishydroxyanisol, 2,2'- thiodiethyl-bis-3- (3,5-ditertiobutyl-4-hydroxyphenyl) propionate), tetrakis- (methylene 3- (3 ', 5'- ditertiobutyl-4'-hydroxyphenyl) propionate) methane, 2, 4-bis-N- octylthio-6- (4-hydroxy 3,5-ditertiobutylanilino) 1,3,5-triazine, di-tertiobutyl-3,5 hydroxy-4 phenyl-3 propionate and octadecyl-3, 5- diter-tiobutyl-4-hydroxyhydrocinnamate.

The tackifying resins (Ab) and (Bb) are chosen in particular from polyterpenes, optionally functionalized with novolaks, rosins and rosin esters and their hydrogenated derivatives, as well as petroleum resins. The petroleum resins which can be used in the systems according to the invention are resins prepared from hydrocarbon fractions originating from the steam cracking of naphthas, such as aromatic cuts. containing at least one alkenylaromatic monomer, aliphatic cuts containing a monomer containing from 5 to 6 carbon atoms, such as cyclopentadiene and its derivatives and cyclohexadiene, or also terpene cuts such as essences of turpentine. As examples of alkenylaromatic units which may enter into the constitution of these resins, mention may in particular be made of units derived from styrene, alphamethylstyrene, indene, vinyltoluene, methylindenes, betamethylstyrene and paratertiobutylstyrene. As examples of terpene units which can enter into the constitution of these resins, mention may in particular be made of units derived from unsaturated cyclic terpenes, preferably monounsaturated, in particular monocyclic such as 1-p-menthene and tetramethylcyclohexene and bicyclic monounsaturated such as pinenes , hulls, limonene, 4 (10) - thujene, 5-isopropylbicyclo [3.1.0] hex-2-ene, 4- methylenepinane, 2-bornene, 2,2,7-trimethyl-2-norbornene and camphene as well as certain bi-unsaturated monocyclic terpenes such as menthadienes. Examples of resins which can be used in the context of the present invention are described in documents EP-A-011 393, EP-A-132 291, EP-A-233 074 and FR-A-2 659 972.

The present invention also relates to a process for the preparation of an adhesive as defined above. This process is characterized by the fact that the components of component (A) and those of component (B) are mixed separately at a temperature sufficient to obtain homogeneous liquids, then components (A) and (B) are intimately mixed with a temperature sufficient to cause the reaction of the primary amine functions present in the component (A) with the functions present in the organic compound of the component (B). Preferably, the constituents of each composition (A) and (B) are mixed at a temperature which is at least 10 ° C higher than the softening point of said composition, for example between 120 ° C and 170 ° C approximately. Preferably, the components (A) and (B) are mixed at a temperature between approximately 120 ° C. and 220 ° C., this temperature being able to be adapted by those skilled in the art as a function of the particular constitution of said components.

The present invention also relates to a method of assembling two objects, characterized in that one brings to a temperature between 120 ° C and 220 ° C approximately each of the components of the hot-melt adhesive, as defined above, then:

- either they are intimately mixed at this temperature, then the resulting hot-melt adhesive is applied to at least one of the two objects to be assembled, and finally one of the two objects to be assembled is applied against the other,

- Either the two compositions are applied separately or one after the other on one of the two objects to be assembled, or one on an object to be assembled and the other on the other object to be assembled, then one applies one against the other said objects. It is sometimes desirable, after having applied the two objects against each other, to heat the assembly for a sufficient time to complete the reactions involved.

The assembly method according to the invention is particularly well suited for the assembly of amorphous or waterproof supports such as in particular mineral glass, polyester, wood, steel.

The amount of adhesive according to the invention applied to the support to be assembled naturally depends on the nature of the latter but it is generally between 5 and 30 grams approximately per square meter of support.

The examples below are given by way of illustration and without limitation of the present invention. EXAMPLE 1 A mixture (A) is first prepared at the temperature of 170 ° C. comprising:

4.5 parts by weight of a polyamide with free amine functions, of viscosity 26 centipoises at 25 ° C. and having an amine level of 400 mg KOH / g, marketed by the company CRAY VALLEY LTD under the name VERSAMIDE 140 ,

50 parts by weight of an ethylene / vinyl acetate copolymer sold by the company DU PONT DE NEMOURS under the name ELVAX 210,

- 10 parts by weight of a tackifying resin sold by the company BERVICK CHEMIE under the name BEVILITE 6285,

- 32.5 parts by weight of a tackifying resin marketed by Cray Valley SA under the brand NORSOLENE ^® 1090,

- 0.5 parts by weight of an antioxidant sold by the company CIBA-GEIGY under the name IRGANOX 1010, and - 2.5 parts by weight of N- [3- (trimethoxysilyl) propyl] ethylene diamine sold by the company UNION CARBIDE under the name SILANE A- 1120.

The other is prepared at the temperature of 170 ° C a mixture (B) comprising: - 36 parts by weight of the tackifying resin NORSOLENE ^® 1090, - 8.5 parts by weight of an ethylene / vinyl acetate copolymer with a flow index of 40 dg / min. (measured according to standard ASTM D-1238) and comprising 28% by weight of vinyl acetate, sold by the company DU PONT DE NEMOURS under the name ELVAX 260,

28.5 parts by weight of an ethylene / ethyl acrylate / maleic anhydride terpolymer of melt index (determined according to standard ASTM D-1238) 400 dg / min., Comprising 24% by weight of acrylate and 3% by weight of anhydride, sold by the company ELF-ATOCHEM under the name LOTADER HC 8571, and

- 0.5 part by weight of the antioxidant IRGANOX 1010.

At 175 ° C. the composition (A) has a viscosity of 6700 centipoises, the composition (B) a viscosity of 11600 centipoises.

For the adhesive obtained by equal weight mixture, at 170 ° C. for 1 minute in a static mixer, of the compositions (A) and (B), the following properties are determined:

- softening temperature above 150 ° C after 30 hours (according to standard NFT 76 106)

- breaking stress (according to NFT 76 107 standard): 4.4 MPa at 23 ° C, 0.16 MPa at 80 ° C.

- elongation at break (according to NFT standard): 310% at 23 ° C, 84% at 80 ° C. EXAMPLE 2

The assembly of amorphous supports of various natures is carried out by application at 170 ° C. of an equiponderal mixture of the compositions (A) and (B) of Example 1. The amount of mixture used is 15 grams per square meter of support. The dynamic shear stress CCD is then measured at 23 ° C and if necessary at 80 ° C, according to standard NFT 76 107, the result being expressed in MPa.

The results are collated in the table below. BOARD

nd = non déterminé EXEMPLE 3

na = not determined EXAMPLE 3

The assembly of a glass support and a steel support is carried out by application at 170 ° C. of an equiponderal mixture of the compositions (A) and (B) of Example 1. The amount of mixture used is 12 grams per square meter of support. Then measured according to NFT 76 112 standard, the 180 ° peel resistance equal to 30 N / cm.

Claims

1. Hot-melt adhesive comprising at least two components capable of reacting with each other, characterized in that it comprises: (A) a first component essentially containing no water or a substance containing water, and comprising at least one primary diamine having from 10 to 100 carbon atoms and at least one organic compound having simultaneously a primary amine function and a hydrolyzable silane function, and (B) a second component essentially containing no water or a substance containing water, and comprising an organic compound having functions capable of reacting with the primary amine functions of the diamine of component (A) and with the functions primary amine of the organic compound of component (A) by releasing water during said reaction. 2. Hot-melt adhesive according to claim 1, characterized in that the primary diamine present in the component (A) carries other non-reactive functions with the functions of the organic compound of the component (B). 3. Hot-melt adhesive according to one of claims 1 and 2, characterized in that the primary diamine present in the component (A) is in the form of a liquid resin. 4. Hot-melt adhesive according to one of claims 1 to 3, characterized in that the primary diamine present in the component (A) is a polyamide with free primary amino functions. 5. Hot-melt adhesive according to one of claims 1 to 4, characterized in that the organic compound with dual functionality primary amine and silane present in the compound (A) has the formula: (RO) ₃ Si (CH ₂ ) m - A - (CH ₂ ) n - NH ₂ (I) in which: - R is a hydrocarbon radical having from 1 to 4 carbon atoms, - m and n are integers each ranging from 1 to 6, and - A is chosen from the groups -NH- and -CH ₂ -, 6. Hot-melt adhesive according to one of claims 1 to 5, characterized in that the organic compound with dual primary amine and silane functionality present in component (A) is N- [3- (trimethoxysilyl) propyl] ethylene diamine. 7. Hot-melt adhesive according to one of claims 1 to 6, characterized in that the component (A) further comprises: - at least one polymer (Aa) chosen from thermoelastic polymers and synthetic rubbers; - at least one tackifying resin (Ab); - at least one antioxidant. 8. Hot-melt adhesive according to claim 7, characterized in that per 100 parts by weight of the component (A) it comprises: - from 2.5 to 9 parts by weight of primary diamine, - from 1.5 to 4.5 parts by weight of organic compound with hydrolyzable silane function, - from 30 to 60 parts by weight of polymer (Aa), - from 25 to 45 parts by weight of tackifying resin (Ab), and - from 0 to 3 parts by weight of antioxidant. 9. Hot-melt adhesive according to one of claims 1 to 8, characterized in that the reactive functions of the organic compound of component (B) are carboxylic acid or carboxylic anhydride functions. 10. Hot-melt adhesive according to one of claims 1 to 9, characterized in that the reactive functions of the organic compound of the component (B) are distributed along a polymer chain. 11. Hot-melt adhesive according to claims 9 and 10 taken in combination, characterized in that said polymer contains, in addition to units derived from an anhydride or carboxylic acid, units derived from at least one alkene and, where appropriate, motifs derived from at least one comonomer. 12. Hot-melt adhesive according to one of claims 1 to 11, characterized in that the organic compound of component (B) is a terpolymer with a melt index of between 2 and 500 dg / min. comprising from 83 to 96 mol% of units derived from ethylene, from 4 to 15 mol% of units derived from an acrylate or Ci-Cι ₂ alkyl methacrylate and from 0.3 to 2 mol% of units derived from maleic anhydride, of molecular weight (number average) of between 5,000 and 100,000. 13. Hot-melt adhesive according to one of claims 1 to 12, characterized in that the organic compound of the component (B) is present in such proportion, relative to the primary diamine and to the organic compound of the component (A), that the ratio molar of the reactive functions of component (B) to the primary amine functions present in component (A) is between 0.6 and 1.4. 14. Hot-melt adhesive according to one of claims 1 to 13, characterized in that the component (B) further comprises: - at least one polymer (Ba) chosen from thermoelastic polymers and synthetic rubbers; - at least one tackifying resin (Bb); - at least one antioxidant. 15. Hot-melt adhesive according to claim 14, characterized in that per 100 parts by weight of the component (B) it comprises: - from 20 to 50 parts by weight of organic compound capable of reacting with the primary diamine and with the organic compound of component (A) while liberating water during said reaction, - from 8 to 15 parts by weight of polymer (Ba), - from 15 to 40 parts by weight of tackifying resin (Bb), and - from 0 to 3 parts by weight of antioxidant. 16. Method for preparing a hot-melt adhesive according to one of claims 1 to 15, characterized in that the components of the component (A) and those of the component (B) are mixed separately at a temperature sufficient to obtain liquids homogeneous, then the components (A) and (B) are intimately mixed at a temperature sufficient to cause the reaction of the primary amine functions present in the component (A) with the functions present in the organic compound of the component (B). 17. Method of assembling two objects, characterized in that the temperature is between 120 ° C and 220 ° C each of the components of the hot-melt adhesive according to one of claims 1 to 15 then: - either they are intimately mixed at this temperature, then the resulting hot-melt adhesive is applied to at least one of the two objects to be assembled, and finally one of the two objects to be assembled is applied against the other, - either apply the two components separately or one after the other on one of the two objects to be assembled, or one on an object to be assembled and the other on the other object to be assembled, then apply one against the other said objects.