EP1685204A1

EP1685204A1 - Method for gluing two materials using a cross-linking adhesive

Info

Publication number: EP1685204A1
Application number: EP04805465A
Authority: EP
Inventors: Bruno D'herbecourt; Annett Linemann
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2003-11-21
Filing date: 2004-11-17
Publication date: 2006-08-02
Also published as: CN1906263A; KR20060088563A; WO2005061640A1

Abstract

The invention relates to a method for gluing two materials using a cross-linking adhesive. More precisely according to the method, a composition (A) is arranged on the side of the material (A), for gluing to the other material (B), a composition (B) is arranged on the side of the material (B), for gluing to the other material (A), the compositions (A) and (B) and the materials (A) and (B) are brought into contact in the presence of heat and, optionally, pressure is exerted on the materials to give a cross-linked adhesive which connects the two materials. According to an advantageous embodiment, the compositions are used in the form of a film, mesh, or non-woven material. In an other embodiment, the composition (A) is fixed to that part of the material (A), for gluing to the other material (B) and the composition (B) is fixed to that part of the material (B), for gluing to the other material (A). In other words, the invention comprises a method for gluing two materials, by means of a cross-linking adhesive in which that part of the material (A) for gluing to the other material (B) is covered with a composition (A), that part of the material (B) for gluing to the material (A) is covered in a composition (B), the two compositions (A) and (B) are brought into contact in the presence of heat and, optionally, a pressure is exerted on the materials to give a cross-linked adhesive connecting the two materials.

Description

Field of the Invention The present invention relates to a method of bonding two materials with a crosslinkable adhesive. More precisely in the process of the invention there is available on the side of the material (A) which has to stick to the other material (B) a composition (A), there is available on the side of the material (B) which must stick on the other material (A) a composition (B), bringing the compositions (A) and (B) into contact with the materials (A) and (B) in the presence of heat and possibly of a pressure exerted on the materials constitutes a cross-linked adhesive that joins the two materials. PRIOR ART AND THE TECHNICAL PROBLEM Hot-melt (adhesive) adhesives are thermoplastic materials which are solid at room temperature and which, on heating, become viscous liquids. These viscous liquids are applied to the surface of a first substrate and then covered with a second surface. By cooling, an adhesion is obtained between the substrate and the second surface. These adhesives are designated by the abbreviation HMA (hot melt adhesives). The bondings thus produced can be used at room temperature and are sufficient. However, when they are subjected to temperatures above ambient temperature and which approach the melting temperature of the adhesive, the adhesion decreases and there is a risk of peeling. This drawback can be remedied by crosslinking the adhesive once the bonding has been completed, thus the adhesive remains in the solid state when the temperature increases and approaches or exceeds the initial melting temperature of the adhesive before it crosslinking. The prior art has described many solutions of this type. Patent EP 940461 describes an HMA consisting of polyethylene in which a reactive powder and a crosslinking agent are dispersed and such that they do not react until the polyethylene is melted. Patent EP 326444 describes a textile covered on one of its faces with an HMA adhesive consisting of a polymer in which an encapsulated crosslinking agent is dispersed. This textile is placed on a material (for example another textile) of so that the adhesive is on the side of the material and pressure is applied while heating. The textile is bonded to the material and at the same time crosslinking of the adhesive. Patent JP1249873 (application JP19880079799) describes a crosslinkable adhesive based on a blocked isocyanate and a polyamine. Patent EP 373878 describes an adhesive in the form of an acrylic resin modified with an aminoamide mixed with a polyol and a radical initiator. Crosslinking is caused by heating. Patent GB 2135673 describes a glass fabric, the fibers of which are coated with an epoxy resin, this fabric then being coated with a polyamide with amino endings. This fabric is placed between two materials that are hot pressed to cause them to stick. US Patent 3,409,497 describes a similar process but the fibers are coated with an OH-terminated bisphenol and the fabric is coated with an epoxy resin. The disadvantage of these techniques is that it is necessary either to separate the components of the adhesive well to avoid crosslinking before the bonding of the two materials or to choose the components of the adhesive well so that there is no crosslinking before a determined temperature and / or that the materials are not well placed one against the other to constitute a final assembly. Furthermore, the components of these crosslinkable adhesives are not simple products. We have now found a much simpler process, we have the side of the material (A) which must stick on the other material (B) a composition (A), we have the side of the material (B) which must stick on the other material (A) a composition (B), bringing the compositions (A) and (B) into contact with the materials (A) and (B) in the presence of heat and possibly of a pressure exerted on the materials constitutes a crosslinked adhesive that joins the two materials together.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a process for bonding two materials with a crosslinkable adhesive. More precisely in the process of the invention there is the side of the material (A) which must stick to the other material (B) a composition (A), we have the side of the material (B) which must stick on the other material (A) a composition (B), bringing the compositions (A) and (B) into contact materials (A) and (B) in the presence of heat and possibly of a pressure exerted on the materials constitutes a crosslinked adhesive which joins the two materials. That is to say that between the materials to be bonded are the compositions (A) and (B), the composition (A) being disposed on the side of the material (A) and the composition (B) being disposed on the side of the material (B). According to an advantageous form, the compositions are in the form of a film, a mesh or a nonwoven. In the rest of the text for simplicity, the film, the mesh and the nonwoven will be designated by "film" or "web". According to a particular form the films

(A) and (B) can be adjacent (and not adherent to each other) but there is no reaction since it is at room temperature. The two films (A) and (B) can be attached with glue dots or by heating the films (A) and (B) at only a few points to make the two films integral and facilitate their handling. According to another form of the invention, the composition (A) is fixed to the part of the material (A) which must stick to the other material (B) and the composition

(B) is fixed on the part of the material (B) which must stick on the other material (A). That is to say that the invention is a method of bonding two materials with a crosslinkable adhesive in which the part of the material (A) which is to stick on the other material (B) is coated with a composition (A) , the part of the material (B) which must stick to the other material (A) is coated with a composition (B), bringing the compositions (A) and (B) into contact in the presence of heat and optionally pressure exerted on the materials constitutes a crosslinked adhesive which joins the two materials. The compositions (A) and (B) can be deposited in the molten state on the materials. According to an advantageous form at least one of these compositions and preferably both are in the form of film, mesh or nonwoven. The film is fixed on the material by a simple hot pressing without melting the film, then the two materials are brought into contact by their part coated with films and heated, possibly exerting pressure on the materials. It would not go beyond the scope of the invention if only one of the compositions was attached to one of the materials (for example the composition (A) on the material (A)). The process of the invention has many advantages: the materials coated with films are easily prepared, it suffices to bring the two materials possibly coated with their film into contact and to press hot to obtain bonding, the compositions (A) and (B) react irreversibly at the time of bonding, thus the thermal resistance is improved at temperatures above the melting points of the compositions (A) and (B) alone, it is possible to choose compositions (A) and (B) which have respectively good adhesion to materials (A) and (B). The present invention also relates to each of the materials coated with the film (A) or (B) as well as the object resulting from the bonding of the materials (A) and (B).

Detailed description of the invention With regard to materials (A) and (B), it can be any material such as wood, paper, cardboard, metal, plastics and woven or nonwoven textiles. . The invention is particularly when at least one of the materials is a textile.

With regard to compositions (A) and (B), all the compositions which can be deposited in the molten state on the material or which can be filmed and which by contacting them hot produce a crosslinked adhesive are thus designated . Mention may be made, for example, of the usual HMAs provided that they each have functions which cause crosslinking. The melting temperature of compositions (A) and (B) is of the order of 60 to 150 ° C. Advantageously, the compositions (A) and (B) are polymers or mixtures of polymers. They can be in the form of film, mesh or nonwoven. The film can be made by the usual techniques of thermoplastic polymer technology, namely extrusion blow molding and "cast", that is to say that the molten material is extruded in a flat die and the polymer is cooled and solidified by passage over cooled rollers. The nonwoven can be produced according to the usual techniques from compositions (A) or (B) which have been put in the form of fibers. For example, the compositions are passed in the molten state in dies and the fibers are recovered on a cold plate, the contact of the fibers with each other before their complete cooling binds them together and forms a nonwoven. As for the mesh, it can be considered as a film with holes or a textile woven with fibers.

As regards the polymers (A), there may be mentioned for example: A1: the copolyamides (CoPA) and the copolymers with copolyamide blocks and polyether blocks,

A2: copolyamides with COOH endings and copolymers with copolyamide blocks and polyether blocks with COOH endings, A3: copolyamides with NH2 endings and copolymers with copolyamide blocks and polyether blocks with NH2 endings,

A4: copolyamides terminated by an acid and copolymers containing copolyamide blocks and polyether blocks terminated by an acid, this acid carrying unsaturated bonds,

A5: copolymers with copolyamide blocks and polyether blocks in which the polyether blocks are made of polybutadiene, advantageously the polyether blocks and the copolyamide blocks are linked by ester groups originating from the reaction between the OH terminations of the polyether and the acid terminations of the copolyamide blocks . These types A1 to A5 can contain a peroxide type initiator.

As regards the polymers (B), there may be mentioned, for example: B1: polymers carrying epoxy functions such as copolymers of ethylene with glycidyl methacrylate (GMA) and optionally with an alkyl (meth) acrylate and copolymers based on epichloridrine, B2: polymers carrying anhydride functions of carboxyic acid such as copolymers of ethylene of maleic anhydride (MAH) and optionally of an alkyl (meth) acrylate, polymers carrying functions of carboxylic acid such as copolymers of ethylene with acrylic acid and optionally with an alkyl (meth) acrylate,

B3: isocyanates (or polyisocyanates) encapsulated in a polyolefin matrix,

B4: polyketones,

B5: the polyureas optionally in a polyolefin matrix,

B6: the polycarbodiimides optionally in a polyolefin matrix,

B7: the ester polyols carrying multiple acrylate groups optionally in a polyolefin matrix,

According to a particular form of the invention (B1) is either a copolymer of ethylene and an unsaturated epoxide or a polyolefin grafted with an unsaturated epoxide. As regards the polyolefin grafted with an unsaturated epoxide, the term polyolefin is understood to mean polymers comprising olefin units such as, for example, ethylene, propylene, butene-1 units, or any other alpha olefin. By way of example, there may be mentioned - polyethylenes such as LDPE, HDPE, LLDPE or VLDPE, polypropylene, ethylene / propylene copolymers, EPRs (ethylene / propylene Rubber) or metallocene PEs (copolymers obtained by catalysis monosite), - styrene / ethylene-butene / styrene block copolymers (SEBS), styrene / butadiene / styrene block copolymers, styrene / isoprene / styrene block copolymers (SIS), styrene / ethylene-propylene block copolymers / styrene, ethylene / propylene / diene (EPDM); - copolymers of ethylene with at least one product chosen from salts or esters of unsaturated carboxylic acids, or vinyl esters of saturated carboxylic acids. Advantageously, the polyolefin is chosen from LLDPE, VLDPE, polypropylene, ethylene / vinyl acetate copolymers or ethylene / alkyl (meth) acrylate copolymers. The density can advantageously be between 0.86 and 0.965, the melt index (MFI) can be between 0.3 and 40 (in g / 10 min at 190 ° C. under 2.16 kg). As regards the copolymers of ethylene and of an unsaturated epoxide, mention may, for example, be made of copolymers of ethylene with an alkyl (meth) acrylate and of an unsaturated epoxide, or copolymers of ethylene, a vinyl ester of saturated carboxyic acid and an unsaturated epoxide. The epoxide amount can be up to 15% by weight of the copolymer and the ethylene amount at least 50% by weight. Advantageously (B1) is a copolymer of ethylene with an alkyl (meth) acrylate and an unsaturated epoxide. Preferably the alkyl (meth) acrylate is such that the alkyl has 2 to 10 carbon atoms. The MFI (melt flow index) of (B1) can be for example between 0.1 and 50 (g / 10 min at 190 ° C under 2.16 kg). Examples of alkyl acrylate or methacrylate which can be used are in particular methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate. Examples of unsaturated epoxides which can be used are in particular: - aliphatic glycidyl esters and ethers such as rallylglycidylether, vinyl glycidylether, glycidyl itaconate and maleate, glycidyl acrylate and methacrylate, and - esters and ethers of glycidyl alicyclic glycidyls such as 2-cyclohexene-1-glycidyl ether, cyclohexene-4,5-diglycidylcarboxylate, cyclohexene-4-glycidyl carboxylate, 5-norbornene-2-methyl-2-glycidyl carboxylate and endocis- bicyclo (2,2 , 1) -5-heptene-2,3-diglycidyl dicarboxylate.

According to a particular form of the invention (B2) is a polymer containing ethylene and an anhydride of unsaturated carboxyic acid. (B2) is either a copolymer of ethylene and of an unsaturated carboxyic acid anhydride or a polyolefin grafted with an unsaturated carboxyic acid anhydride. The polyolefin can be chosen from the polyolefins mentioned above and which have to be grafted with an unsaturated epoxide. Examples of unsaturated dicarboxylic acid anhydrides which can be used as constituents of (B2) are in particular maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride. By way of examples, mention may be made of copolymers of ethylene with an alkyl (meth) acrylate, of an unsaturated carboxyic acid anhydride and copolymers of ethylene, of a vinyl acid ester. saturated carboxy and an unsaturated carboxy anhydride. The amount of unsaturated carboxylic anhydride can be up to 15% by weight of the copolymer and the amount of ethylene at least 50% by weight. Advantageously (B2) is an ethylene copolymer of an alkyl (meth) acrylate and of an unsaturated carboxylic anhydride. Preferably the alkyl (meth) acrylate is such that the alkyl has 2 to 10 carbon atoms. The alkyl (meth) acrylate can be chosen from those mentioned above. The MFI of (B) can for example be between 0.1 and 50 (g / 10 min at 190 ° C. under 2.16 kg).

Irreversible bonding with very good temperature resistance is obtained by combining: web A1 with web chosen from B1, B2, B3, B4 and B6, web A2 with web chosen from B1, B3 and B6, web A3 with web chosen from B1, B2, B3, B4, B5, B6 and B7, A4 web with web chosen from Blet B7, A5 web with B7 web. Examples

The following products were used:

Lotader® 7500: designates an ethylene-ethyl acrylate-maleic anhydride copolymer with proportions by weight 80/17/3, of MFI 70 g / 10min at 2.16 kg at

190 ° C. It is produced by radical polymerization under high pressure.

Lotader® AX8950: denotes an ethylene-methyl acrylate-glycidyl methacrylate copolymer with proportions by weight 72.2 / 18.8 / 9, of MFI 90 g / 10 min at 2.16 kg at 190 ° C. It is produced by radical polymerization under high pressure.

Platamid®1: denotes a copolyamide 6.9 / 12 in mass proportions 30/70 obtained by condensation of hexamethylene diamine, C9 diacid and lauryllactam. It is finished di-COOH, the MFI is 15 g / 10min under 2.16 kg at

160 ° C.

Piatamid®2: designates a copolyamide essentially based on hexamethylene diamine, caprolactam, adipic acid, C10 diacid and aminoundecanoic acid. The MFI is 9 g / 10 min under 2.16 kg at 150 ° C.

Platamid®3: denotes a copolyamide 6 / 6.6 / 12 in proportions 40/20/40 obtained by condensation of hexamethylene diamine, adipic acid and lauryllactam. Films of Platamid® and Lotader® with a thickness of 50 μm were made and then the bonding of these films was carried out in a press under the following conditions: 60 sec, 280 dN, T (Lotader side) = 75 ° C., T (Platamid side) = 150 ° C. The results are reported in the following Tables 1 and 2 in which the rate of gels proves crosslinking. Table 1

Table 2

Claims

1 Method of bonding two materials with a crosslinkable adhesive in which there is the side of the material (A) which must stick on the other material (B) a composition (A), there is the side of the material (B) which must sticking on the other material (A) a composition (B), bringing the compositions (A) and (B) into contact with the materials (A) and (B) in the presence of heat and possibly of a pressure exerted on the materials constitute a crosslinked adhesive which joins the two materials.

2 The method of claim 1 wherein the compositions (A) and (B) are in the form of film, mesh or nonwoven (designated by "film").

3 The method of claim 2 wherein the two films are attached (A) and (B) by dots of glue to make the two films integral and facilitate their handling.

4 The method of claim 2 wherein the two films are attached (A) and (B) by heating the films (A) and (B) at only a few points to make the two films integral and facilitate their handling.

5 A method of bonding two materials with a crosslinkable adhesive in which the part of the material (A) which has to stick on the other material (B) is coated with a composition (A), the part of the material (B) which must sticking to the other material (A) is coated with a composition (B), bringing the compositions (A) and (B) into contact in the presence of heat and possibly of a pressure exerted on the materials constitutes a crosslinked adhesive which combines the two materials.

6 The method of claim 5 wherein the compositions (A) and (B) are deposited in the molten state on the materials. 7 The method of claim 5 wherein at least one of the compositions (A) or (B) is in the form of film, mesh or nonwoven (designated by "film").

8 The method of claim 7 wherein the film is fixed on the material by a simple hot pressing without melting the film, then the two materials are brought into contact by their part coated with films and heated, possibly exerting pressure on materials.

9 Method according to any one of the preceding claims, in which the composition (A) is chosen from:

A1: copolyamides (CoPA) and copolymers with copolyamide blocks and polyether blocks,

A2: the copolyamides with COOH endings and the copolymers with copolyamide blocks and polyether blocks with COOH endings,

A3: copolyamides with NH2 endings and copolymers with copolyamide blocks and polyether blocks with NH2 endings,

A5: copolymers with copolyamide blocks and polyether blocks in which the polyether blocks are made of polybutadiene.

10 Method according to any one of the preceding claims, in which the composition (B) is chosen from:

B1: polymers carrying epoxy functions such as ethylene copolymers of glycidyl methacrylate (GMA) and optionally of an alkyl (meth) acrylate and copolymers based on epichloridrine, B2: polymers carrying carboxyic acid anhydride functions such as ethylene copolymers of maleic anhydride (MAH) and optionally of an alkyl (meth) acrylate, the polymers carrying carboxyic acid functions such as copolymers of ethylene with acrylic acid and optionally with an alkyl (meth) acrylate,

B3: isocyanates (or polyisocyanates) encapsulated in a polyolefin matrix,

B4: polyketones,

B5: the polyureas optionally in a polyolefin matrix,

B6: the polycarbodiimides optionally in a polyolefin matrix,

B7: ester polyols carrying multiple acrylate groups optionally in a polyolefin matrix.

11 The method of claim 10 wherein (B1) is an ethylene copolymer of an alkyl (meth) acrylate and an unsaturated epoxide.

12 The method of claim 10 wherein (B2) is an ethylene copolymer of an alkyl (meth) acrylate and an unsaturated carboxylic anhydride.