MXPA06002685A - Peelable hot melt adhesive - Google Patents

Abstract

A hot melt adhesive comprising a thermoplastic elastomer, a tackifying resin and a plasticizer. The adhesives are particularly useful in automotive applications.

Description

FUSION ADHESIVE IN HOT DESPRENDIBLE FIELD OF THE INVENTION The present invention relates to hot melt adhesive compositions, and more particularly to hot melt adhesives and their use in automotive applications. BACKGROUND OF THE INVENTION Hot melt adhesives are widely used for various commercial and industrial applications such as assembly and packaging of the product. Such hot melt adhesives are applied to a substrate while in their molten state and cooled they harden the adhesive layer. Most commercially available hot melt adhesives do not provide the necessary properties required for automotive applications. For example, conditions found by hot melt adhesives during automotive applications are extremely harsh and include exposures to temperatures ranging from -30 ° C to 120 ° C and environments that contribute to oxidation. Thus, a hot melt adhesive for automotive applications should provide good thermal stability, low Tg, oxidation resistance and, preferably, a low content of volatile materials.

Accordingly, it would be desirable to have thermoplastic adhesives based on elastomers which exhibit good adhesion resistance with exceptional firmness viscosity, tensile strength and application under extreme environmental conditions. The current invention addresses this need in the art. SUMMARY OF THE INVENTION The invention provides an adhesive that can be formulated for applications in the harsh conditions encountered with automotive applications, yet still provides exceptional firmness. One aspect of the invention is directed to a hot melt adhesive comprising a thermoplastic elastomer, an adherent resin and a plasticizer. In one embodiment the adhesives of the invention comprise, based on the total weight of the adhesive composition, from about 1 to about 10% by weight of a plastic elastomer, from about 10 to about 60% by weight of an adherent resin, and from about 20 to about 80% by weight of a plasticizer. The adhesives of the invention may desirably also comprise additional ingredients, such as diluents, waxes, antioxidants, fillers, additional plasticizers and aromatic resins. Another aspect of the invention is directed to an article of manufacture comprising a hot melt adhesive wherein the adhesive comprises a thermoplastic elastomer, an adherent resin and a plasticizer. Manufacturing articles will typically comprise at least one substrate. Yet another aspect of the invention is directed to a process for adhering a substrate to a similar or dissimilar substrate comprising applying at least a first substrate to a hot melt adhesive composition, which leads to at least one second substrate in contact with the substrate. adhesive present on the first substrate whereby the first and second substrates are adhered together. The adhesive composition used in the process comprises a thermoplastic elastomer, an adherent resin and a plasticizer. DETAILED DESCRIPTION OF THE INVENTION All documents cited herein are incorporated in their totals as a reference. The present invention provides a hot melt adhesive composition useful in automotive applications. Due to its use in harsh surface environments and variants found in automotive applications, the hot melt adhesive of the present invention preferably provides a relatively flat elastic modulus of -20 ° C to 150 ° C, a viscosity at 180 ° C. of about 35,000 mPa, extremely good thermal stability, Tg of about -32 ° C, fogging temperature > 100 ° C, and a low content of volatile materials < 0.10% after two hours at 110 ° C. The hot melt adhesive compositions according to the present invention are more suitable for harsh surface environments encountered during automotive applications than the standard hot melt adhesive formulations. The hot melt adhesives of the invention comprise a thermoplastic elastomer, an adherent resin, a plasticizer and, if desired, other additives such as aromatic resins, fillers, additional plasticizers, antioxidants, diluents, waxes and the like. The adhesives of the invention typically comprise from about 1 to about 15% by weight, and preferably from about 6 to about 9% by weight, of at least one thermoplastic elastomer. The polymers that can be used in the preparation of the thermoplastic elastomer component of the adhesive compositions of the present invention are block copolymers having the general ABA configuration wherein the final polymer A blocks are non-elastomeric polymer blocks which, like homopolymers, they have glass transition temperatures above about 20 ° C, while the intermediate B blocks of elastomeric polymer are issprene, butadiene or isobutylene derivatives which can be partially or substantially hydrogenated or mixtures thereof. In addition, copolymers can be linear or branched. Typical branched structures contain an elastomeric portion with at least three branches that can radiate out of a central core or can otherwise be coupled together. The non-elastomeric end blocks may comprise homopolymers or copolymers of vinyl monomers such as vinylarenes, vinylpyridines, vinyl halides and vinyl carboxylates, as well as acrylic monomers such as acrylonitrile, methacrylonitrile, esters of acrylic acids, etc. Aromatic vinyl hydrocarbons include particularly those of the benzene series such as styrene, vinyltoluene, vinylxylene, and ethylvinylbenzene as well as dicyclic monovinyl compounds such as vinylnaphthalene and the like. Other non-elastomeric polymer blocks may be derived from alpha olefins, alkylene oxides, acetals, urethanes, etc. Styrene is preferred. The elastomeric intermediate block B component forming the remainder of the thermoplastic elastomeric copolymer is typically derived from isoprene, butadiene or isobutylene which can be hydrogenated as described, for example, in U.S. Patent No. 3,700,633. This hydrogenation of butadiene may be partially or substantially complete. Conditions selected for example to hydrogenate the elastomeric butadiene block while modifying the polymer blocks can be employed. vinylarene Other conditions may be selected to be substantially uniformly hydrogenated together with the polymer chain, both the elastomeric and non-elastomeric blocks thereof which are hydrogenated to substantially the same degree, which may be either partially or substantially complete. Hydrogenated polymers are preferred to minimize degradation during processing, which is a more serious problem with higher molecular weight polymers. In the case of the high viscosity triblock copolymers employed herein, they may have the more general ABA configuration where polymer A blocks are non-elastomeric polymer blocks which, as homopolymers have glass transition temperatures above 20 ° C. , while - the elastomeric polymer blocks B are isoprene, or butadiene which may be partially or substantially hydrogenated or mixtures thereof. In addition, the copolymers can be linear or branched. Typical branched structures contain an elastomeric portion with at least three branches that may radiate away from a central core or may be another way to mate together. The amount of the triblock component is preferably from about 1 to about 20 parts by weight, more preferably from about 3 to about 8 parts by weight. The high viscosity triblock copolymer of the invention can have a wide range of the elastomeric end block to elastomeric core block ratio of about 5:95 or less to about 40:60 or greater. Examples of high viscosity triblock copolymers that can be used to achieve one or more of the novel properties of the present invention are styrene-ethylene-butylene-styrene block copolymers (SEBS) available from Shell Chemical Company and Pectén Chemical Company under the brand designations Kraton G 1651, KRATON G 1654, KRATON G 4600, KRATON G 4609 and the like. Other polymer grades (SEBS) can also be used in the present invention, provided that such SEBS polymers have the required high viscosity. Such SEBS polymers include (high viscosity) KRATON G 1855X having a Specific Gravity of 0.92, Brookfield viscosity of a solids solution of 25 weight percent in toluene at 25 ° C of about 40,000 cps or from approximately 8,000 to approximately ,000 cps to a solids solution of 20 weight percent in toluene at 25 ° C. Although the typical ratio values for Kraton G 1651, 4600 and 4609 are approximately 33:67 and for KRATON G 1855X approximately 27:73, as previously noted, these ratios can vary widely from the product specification values Typical Another example of high viscosity block copolymers are polystyrene-b-poly (ethylene-ethylene / propylene) -b-polystyrene (SEEPS). Most preferred SEEPS include SEPTON 4055 and 4077, commercially available from Kuraray Co., Ltd. SEEPS are high performance thermoplastic rubbers comprising a series of hydrogenated styrenic block copolymers having rubber-like properties over a wide range of temperatures. SEEPS provide the benefits of excellent mechanical properties, good weather resistance, excellent low temperature properties, superior thermal resistance, excellent chemical resistance and low toxicity. It is preferred that the adhesive additionally contain up to 10 and preferably 0 to 5 parts by weight of a high molecular weight diblock polymer (ie, viscosity> 1000 cps at 25 ° C in 20% toluene) of the AB configuration general where A and B are as previously described. KRATON G 1701X or 1702X are preferred which are both styrene-ethylene-propylene diblock polymers (SEP). KRATON G1702X is more preferred. While the adhesive formulation preferably contains. some diblock polymer, the diblock can be replaced completely or in part with another high molecular weight polymer that is compatible with the system. For example, polyisobutylene (e.g., Exxon VISTANEX), polyisoprene (e.g., Kuraray), or styrene / butadiene copolymer (e.g., Goodyear PLIOFLEX) may be used in amounts of about 2 to 10 parts by weight. More preferred is a mixture of at least one SEEPS and at least one SEP which are adhered with hydrogenated hydrocarbon resins and aliphatic resins. As will be described below, various additives are known to be associated with particular blocks (domains) of polymers in blocks, which alter the behavior of the portions accordingly. In greater detail, the intermediate block or domain portion (ie "B block") of the polymer needs to have a Tg less than about room temperature. Other compatible components of the intermediate block are added as plasticizing and adherent oils, these components associated with the B domains increasing them, and which generally result in a change in the Tg thereof. For more pressure sensitive adhesive applications, a Tg in the range of about 0 ° C to 25 ° C, preferably about 15 ° C; however, variations in Tg in the intermediate block of about -30 ° C to about 10 ° C, more preferably about -20 ° C to about 0 ° C, are required for use herein. The adhesives of the invention will typically comprise from about 5 to about 60% by weight of an adherent resin. Preferred adhesive compositions will comprise from about 30 to about 50% by weight of an adherent resin which is compatible with the intermediate block of the thermoplastic elastomer. Adherents having an Annular and Spherical softening point above about 25 ° C are preferred. Suitable adherents include any compatible resins or mixtures thereof such as (1) natural or modified rosins such, for example, as rubber rosin, wood rosin, liquid resin rosin, distilled rosin, hydrogenated rosin, dimerized rosin and polymerized rosin; (2) esters of glycerol and pentaerythritol of natural or modified rosins, such as, for example, the glycerol ester of wood rosin, clear, the glycerol ester of hydrogenated rosin, the glycerol ester of polymerized rosin, the pentaerythritol ester of hydrogenated rosin, and the phenol-modified pentaerythritol ester of rosin; (3) copolymers and terpolymers of natural terpenes, for example, styrene / terpene and alpha methyl styrene / terpene; (4) polyterpene resins having a softening point, as determined by the method of ASTM E28.58T, from about 80 ° to 150 ° C; the subsequent polyterpene resins generally resulting from the polymerization of terpene hydrocarbons, such as the bicyclic monoterpene known as pinene, in the presence of Friedel-Crafts catalysts at moderately low temperatures; also include hydrogenated polyterpene resins; (5) phenolic-modified terpene resins and hydrogenated derivatives thereof, for example, as the resin product resulting from the condensation, in an acid medium, of a bicyclic terpene and phenol; (5) Aliphatic petroleum hydrocarbon resins having a Spherical and Annular softening point from about 70 ° to 135 ° C; the subsequent resins resulting from the polymerization of monomers consisting mainly of olefins and diolefins; hydrogenated aliphatic hydrocarbon oil resins are also included; (7) alicyclic petroleum hydrocarbon resins and the hydrogenated derivatives thereof; and (8) aliphatic / aromatic or cycloaliphatic / aromatic copolymers and their hydrogenated derivatives. Preferred adherents for use herein include polyterpenes such as WINGTACK 95 from Goodyear; aliphatic resins such as HERCURES C from Hercules; cycloaliphatic resins such as EASTOTAC H100R from Eastman; and aliphatic / aromatic or cycloaliphatic / harmonic resins such as ESCOREZ 5600 from ExxonMobil Chemical Company. Aliphatic and cycloaliphatic resins are more preferred. More preferred are fully hydrogenated or partially hydrogenated hydrocarbon resins, such as ECR 398 from ExxonMobil, ESCOREZ 5320 from ExxonMobil, and ESTOTAC H142R or H130 from Eastman. The convenience and selection of the particular tackifier may depend on the specific elastomeric block copolymer employed. Additionally, it may be desirable to incorporate up to about 5% by weight of a final block adhesive resin into the adhesive. The final block adherent resin residue predominantly in the non-elastomeric blocks of the thermoplastic elastomer after the adhesive is cooled. Representative of such resins are mainly aromatic resins based on C9 petroleum distillation streams mixed as HERCURES materials available from Hercules, or resins based on pure monomer streams or mixed aromatic monomers such as vinyltoluene homo- or copolymers, styrene, alpha-methyl-styrene, coumarone or indene. Preferred are those based on styrene-alpha-methylstyrene available from Hercules under the trade name KRISTALEX. More preferred are KRISTALEX 3155 or ENDEX 155, commercially available from Eastman. For adherent products, the aromatic resin must be mixed with C5 or hydrogenated resin. For non-adherent products, aromatic resin modified with phenol is preferred. If present, the final block resin is generally used in an amount of from about 10 to about 50% by weight, preferably about 30% by weight. Also present in the adhesive is up to about 80% by weight, preferably from about 30 to about 60% by weight, of an oil or other diluent liquid that is primarily aliphatic in character and compatible with the intermediate block of thermoplastic elastomer. Examples include plasticizers such as paraffinic and naphthenic oils, petroleum-white mineral oils of technical and food grade, paraffinic and naphthenic, free of highly refined aromatics, and liquid adherents, such as synthetic liquid oligomers of polybutene, polypropylene, polyterpene, etc. The oils in synthetic series process are high viscosity oligomers that are permanently monoolefins, isoparaffins or fluid liquid paraffins of moderate to high molecular weight. More preferred are hydroisomerized plasticizers, such as NEXBASE 380, commercially available from Fortum Base Oils, synthetic oil, such as DURASYN 168 or polyalphadefines, such as DURASYN 162, 164, 168 or 180, commercially available from BP Amoco, CHEMLUBE 221, 228, 268, 520, commercially available from Ultrachem, LUCANT HC 10, 100, 600, commercially available from Mitsui Chemicals, and the range of Mobil SHF and SuperSyn commercially available from ExxonMobil. Adherent diluents or liquid plasticizers include polyterpenes such as WINGTACK 10 available from Goodyear, and ESCOREZ 2520 can also be included based on a C5 food stream from Exxon Chemical. Other liquid diluents include polyisoprene, available as Lura 50 from Kuraray, and polybutenes from Amoco available under the name indopol and paraffinic oils in combination with Escorez 2520, a polymerized C5 petroleum feed stream. Additional plasticizers may also be included, including phthalates such as VESTINOL TD, commercially available from Degussa and JAYFLEX DTDPZ, commercially available from Exxon. Also, optionally, up to about 6% by weight and preferably up to about 0.5% by weight of a wax may be present. Waxes suitable for use in the present invention include paraffin waxes, microcrystalline waxes, polyethylene waxes, polypropylene waxes, polyethylene by-product waxes, Fischer-Tropsch oxidized waxes and functionalized waxes such as hydroxystearamide waxes and fatty amide waxes. It is common in the art to use the terminology synthetic waxes of high melting point including high density low molecular weight polyethylene waxes, polyethylene by-product waxes and Fischer-Tropsch waxes. Modified waxes, including vinyl acetate modified waxes such as AC-400 (Honey ell) and MC-400 (available from Marcus Oil Company), waxes modified with maleic anhydride such as EPOLENE C-18 (available) can be used in the practice of the invention. from Eastman Chemical) and AC-575A and AC-575P (available from Honey ell) and oxidized waxes. Particularly preferred are polyethylene waxes. If used, the wax is generally present in an amount of at least about 1% by weight. Fillers may also be optionally included in the adhesives. Suitable fillers include, but are not limited to, calcium carbonate, glass microspheres or glass bubbles and ceramic microspheres, commercially available as 3M SCOTCHLITE, silica, and molecular sieves, such as SLIPORITE, commercially available from Ceca SA and PURMOL, commercially available from Zeochem and mixtures thereof. Other ingredients, such as UV absorbers, can also be included. Finally, typical antioxidants used in the production of pressure-sensitive adhesives based on rubber in an amount of up to about 3% by weight may be present. Useful stabilizers or antioxidants used herein include hindered phenols of high molecular weight and multifunctional phenols such as phenols containing sulfur and phosphorus. Hindered phenols are well known to those skilled in the art and can be characterized as phenolic compounds that also contain spherically bulky radicals in close proximity to the phenolic hydroxyl group thereof. In particular, tertiary butyl groups are generally substituted in the benzene ring in at least one of the ortho positions relative to the phenolic hydroxy group. Representative hindered phenols include: 1, 3, 5-trimethyl-2,4,6,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -benzene; Pentaerythritol tetrakis-3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate, '4,4' -methylene-bis (2,6-tert-butylphenol); 4,4'-thiobis (6-tert-butyl-o-cresol); 2,6-di-tert-butylphenol; 6- (4-hydroxyphenoxy) -2,4-bis (n-octylthio) -1,2,5-triazine; D-n-octadecyl 3, 5-di-tert-butyl-4-hydroxybenzyl phosphonate; 3, 5-di-tert-butyl-4-hydroxybenzoate of 2- (n-octylthio) ethyl; and hexa [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) -propionate] of sorbitol. Hot melt adhesives can be prepared using techniques known in the art.

Typically, the adhesive compositions are prepared by mixing the components in the melt at a temperature of about 100 ° C to 200 ° C until a homogeneous mixture is obtained. Various mixing methods are known and any method that produces a homogeneous mixture is satisfactory. As noted above, there are a variety of ways to formulate the particular raw materials in order to obtain an adhesive having the intermediate block values Tg, G 'and G "In addition, the particular end use for which the Adhesive will also affect the choice of materials and the maximum values of Tg, G 'and G ".

In general, it has been found that tribloque rubber provides fixation of the adhesive in a gelatinous solid, while rubber diblock improves the adhesion of the formulation. The final block resins provide resistance to the adhesive formulation while decreasing its melt viscosity by reducing the self-bonding of the rubber end blocks when they are fused. In the formulation of the adhesives, predominantly liquid diluents are used to ensure a low Tg for the matrix (intermediate block portion) of the formulation. A preferred adhesive composition comprises (a) from about 7 to about 9% by weight of a blend of thermoplastic elastomers such as styrene-ethylene-propylene (SEP) and polystyrene-b-poly '(ethylene-ethylene / propylene) -b-polystyrene (SEEPS) ie adhered with hydrogenated hydrocarbon resins and aliphatic resins; (b) from about 30 to about 35% by weight of an adherent resin which is compatible with the intermediate block of the block copolymer listed in (a); and (c) from about 40 to about 50% by weight of a plasticizer as a synthetic or hydroisomerized oil. In the most preferred composition the adhesive further comprises (d) of 0 to about 10% by weight of liquid resins; (e) of 0 to about 5% by weight of wax; (f) from about 0 to about 10% by weight aromatic resin selected from the range of styrene-alpha-methylstyrene resins; (g) from about 0 to about 2% by weight of antioxidants; (h) from about 0 to about 20% by weight of fillers; and (i) additional plasticizers. The adhesive can be applied to a desired substrate by any method known in the art, and includes, without limitation roller coating, painting, dry brushing, dip coating, spraying, slot coating, turbulence spray, printing (e.g. ink jet printing), flexographic, extrusion, atomized spray, gravure (transfer of design wheels), electrostatic, vapor phase deposition, fiberization and / or screen printing.

The adhesives of the invention are useful as placement adhesives, core adhesives or elastic adhesives, and are particularly suitable for use in the manufacture of articles, including but not limited to articles used in automotive applications. "Linked" or "joined" refers to the union, adhesion, connection, or the like, of two elements. Two elements are considered joined together when they are directly linked to each other or indirectly to each other (for example, when each element is directly linked to an intermediary element). The invention is illustrated - in addition by the following non-limiting examples. EXAMPLES In the following examples, all parts are by weight and all temperatures in degrees Fahrenheit, unless otherwise noted. Adhesive preparation. All the formulations described herein were prepared in a 600 g Brabender mixer with paddles in the form of a sigma. The mixing process ended when the mixture was homogeneous. The rubbers and almost half of the oil in the formulation were added to the bowl preheated to approximately 325 ° F. Once homogeneous, additional oil was added along with any other liquid diluents. Finally, the final block adherent was added. The following materials were used to prepare a series of adhesives according to the present invention. The adhesive samples were subjected to the test described below: Fusion viscosities of the hot melt adhesives were determined in a Brookfield viscometer Model RVT Ther osel using a number 27 spindle. Example 1 Two melt adhesive formulations were prepared hot with the ingredients (listed in percent by weight) listed in Table 1. Table 1. Hot melt compositions Mixture of SEEPS and SEP elastomers As shown, Formulation 1 contains a polyalphaolefin plasticizer, while Formulation 2 contains a mineral oil in place of the polyalphaolefin. The test results in the formulations are shown in Table 2.

Table 2. Plasticizer properties Table 3. Properties of the Composition As shown in Table 2, the composition containing the polyalphaolefin provides superior performance than without the composition. Example 2. Nine additional compositions were formulated according to the procedure of Example 1. The formulations are set forth in Table 4 (all components are in percent by weight).

Table 4. Composition formulations ^ EPTON 4055 2SEPT0N 4077 3ECR 398"EXCOREZ 5320 5ENDEX 155 6NEXBASE 3080 DURASIN 168 8PRIMOL 352 9KRATON 1702 The results of the test in compositions A-I are set forth in Table 5.

Table 5. Test results in the compositions aMeasurement in a Steevens Texture Analyzer 2Measurement in a Brookfield Viscometer at 180 ° C 3Measurement in a Bohlin Rheometer, frequency 1 Hertz ^ Visual measurement 5Mp? = c5 r-a < s nt ?? ns r3t-? ' ? ra 5 fahi-i rarls'! nnr A =; ah? rhpmi to .TP As shown in Table 5, the formulations containing the thermoplastic elastomer of SEP and / or SEEP produced superior results. Many modifications and variations of this invention can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. The specific embodiments described herein are offered by way of example only, and the invention is to be limited only by the terms of the appended claims, together with the full scope of the equivalents for which such claims are entitled.

Claims (19)

1. CLAIMS 1. An adhesive, characterized in that it comprises a thermoplastic elastomer selected from the group consisting of styrene-ethylene-propylene, polystyrene-b-poly (ethylene-ethylene / propylene) -b-polystyrene and mixtures thereof, an adhesive resin of Fully hydrogenated or partially hydrogenated hydrocarbon and a plasticizer.
2. 2. The adhesive according to claim 1, characterized in that the plasticizer is a polyalphaolefin.
3. The adhesive according to claim 1, characterized in that it comprises from about 1 to about 10% by weight of the thermoplastic elastomer, from about 10 to about 60% by weight of the tackifying resin, and from about 20 to about 80% by weight of the adhesive resin. plasticizer weight. .
4. The adhesive in accordance with the claim 1, characterized in that the thermoplastic elastomer is adhered with hydrogenated hydrocarbon resins and / or aliphatic resins.
5. 5. The adhesive in accordance with the claim 2, characterized in that the polyalphaolefin is selected from the group consisting of hydroisomerized oil, synthetic oil and mixtures thereof.
6. The adhesive according to claim 1, characterized in that it also comprises aromatic resins.
7. The adhesive according to claim 6, characterized in that the aromatic resins are selected from the group consisting of styrene-alpha-methyl-styrene resins.
8. The adhesive according to claim 6, characterized in that it comprises from about 0 to about 10% by weight aromatic resin.
9. 9. The adhesive according to claim 6, characterized in that the aromatic resin is mixed with hydrogenated resin.
10. The adhesive according to claim 6, characterized in that the aromatic resin is an aromatic resin modified with phenol.
11. 11. The adhesive according to claim 1, characterized in that it further comprises one or more of the group consisting of wax, diluents, fillers, antioxidants, liquid resins, additional plasticizers and mixtures thereof.
12. 12. The adhesive according to claim 1, characterized in that the filler comprises calcium carbonate.
13. The adhesive according to claim 1, characterized in that it also comprises up to about 80% by weight of a diluent and / or up to about 6% by weight of a wax.
14. 14. An article or product of manufacture, characterized in that it comprises the adhesive according to claim 1.
15. 15. The article according to claim 14, characterized in that it also comprises at least one substrate.
16. 16. The article according to claim 13, characterized in that the adhesive comprises from about 1 to about 10% by weight of the thermoplastic elastomer, from about 10 to about 60% by weight of the tackifying resin, and from about 20 to about 80. % of the plasticizer.
17. 17. The article according to claim 16, characterized in that the adhesive further comprises one or more of the group consisting of wax, diluents, fillers, liquid resins, additional plasticizers and mixtures thereof.
18. 18. A process for joining a first substrate to a second substrate, characterized in that it comprises applying to at least the first substrate the adhesive according to claim 1, the second substrate in contact with the adhesive present in the first substrate, so which the first substrate is attached to the second substrate.
19. 19. The process according to claim 18, characterized in that at least one substrate is a component for use in an automotive application.