Silylated adhesive composition with improved adhesion to metal substrates

Abstract

1)--a moisture-curable silylated adhesive composition comprising 20%-50% by weight of a silane-modified APAO, 2%-15% by weight of a filler consisting of expanded hollow thermoplastic polymer microspheres, and 10%-60% by weight of a tackifier. 2)--a method for producing an assembled product comprising--heating said composition at 130° C.-180° C. to make it sufficiently liquid for application onto a substrate, then--coating said composition onto a surface of a primary substrate, then--contacting the coated surface of the primary substrate with a surface of a secondary substrate, and then--chemically curing the coated composition with water, preferably atmospheric moisture.

Description

[Technical Field]

[0001] The present invention relates to a moisture-curable polyolefin hot-melt adhesive composition with improved adhesion to metal substrates, and to its use for assembling substrates including metal substrates, preferably aluminum substrates. [Background technology]

[0002] Hot-melt adhesives are solvent-free adhesives that are solid at room temperature and applied to substrates to be bonded in molten form. After cooling, the adhesive solidifies and forms an adhesive bond with the substrate through physically occurring bonding. Conventional hot-melt adhesives are non-reactive adhesives that soften again when heated and are therefore unsuitable for use at high temperatures. Hot-melt adhesives are generally provided in the form of a composition comprising a thermoplastic polymer and, optionally, a tackifying resin and a plasticizer.

[0003] Reactive hot-melt adhesives contain polymers with reactive groups that enable chemical curing of the adhesive, for example, by crosslinking polymer chains into a three-dimensional solid network. Due to this curing network, reactive hot-melt adhesives do not soften when heated, and therefore these adhesives are also suitable for use at high temperatures.

[0004] The chemical curing of polymers can be initiated, for example, by heating the composition or exposing it to water. Moisture-curing hot-melt adhesives typically contain polymers functionalized with isocyanate or silane groups, allowing for crosslinking of polymer chains when in contact with water present on the surface of the substrate to be assembled, particularly atmospheric moisture or moisture.

[0005] Typical moisture-curing hot-melt adhesives used as assembly adhesives in the transportation industry, particularly the automotive industry, include polyurethane-based and polyolefin-based hot-melt adhesives.

[0006] Reactive hot-melt polyurethane (HMPUR) adhesives consist primarily of isocyanate-terminated polyurethane prepolymers, which are obtained by reacting a suitable polyol, typically a diol, with a stoichiometrically excess polyisocyanate, typically a diisocyanate. Upon contact with water, the residual isocyanate groups of the polyurethane prepolymer form carbamic acid, which is unstable and decomposes into amines and carbon dioxide. The amines rapidly react with other isocyanate groups to form urea bonds.

[0007] State-of-the-art HMPUR adhesives have certain drawbacks. One drawback is the residual monomer content of polyisocyanates, particularly the more volatile diisocyanates. Some HMPUR adhesive compositions may contain significant amounts of unreacted monomeric diisocyanates. At hot-melt application temperatures (typically 100°C to 170°C), monomeric diisocyanates have considerable vapor pressure and can be partially released in gaseous form. Since isocyanate vapors are toxic, irritating, and have a sensitizing effect, precautions must be taken during the application process. Another drawback of state-of-the-art HMPUR adhesives stems from the fact that their adhesion to non-polar substrates such as polypropylene and polyethylene is insufficient, and therefore, when applied to bond such non-polar substrates, the corresponding substrate surface must be pre-treated with a primer. Such pre-treatment significantly increases the total application cost.

[0008] Reactive hot-melt polyolefin adhesives (HMPORs), particularly those based on silane-modified amorphous poly-α-olefins (or "amorphous poly-α-olefins" abbreviated as APAO), have been developed to replace HMPOR adhesive compositions. Due to their high non-polarity properties, they are suitable for bonding non-polar substrates such as polypropylene and polyethylene, as well as corresponding composites, without, in principle, pre-treatment of the substrate surface with a primer. Furthermore, because they do not contain isocyanates, there are no concerns about the release of isocyanate monomer vapors.

[0009] Reactive polyolefin hot-melt adhesives based on silane-modified poly-α-olefins are disclosed, for example, in U.S. Patent No. 5,994,474 and U.S. Patent No. 8,865,822. Upon contact with water, silane groups of polyolefin polymers, such as methoxysilane groups, react with water to form silanols, which then, as part of a condensation reaction, react with other silanol groups to form siloxane covalent bonds between individual polymer molecules.

[0010] In the automotive industry, HMPOR is widely used in the manufacture of headliners, armrests, or door panel laminates. However, due to its relatively low adhesion to polar substrates, it is difficult to use for bonding polar substrates such as PMMA or metals such as aluminum. Currently, with the increasing development of automotive headliners such as skylights, metal frames, especially aluminum frames, are increasingly being used as supports for skylight window systems, for example. For these types of uses, current reactive HMPORs have not been feasible due to their lack of adhesion to aluminum.

[0011] SIKA's PCT application, International Publication 2019 / 048593, describes an adhesive composition comprising a single thermoplastic resin silane group-containing poly-α-olefin and a reaction product of a monoisocyanate and a silane containing one isocyanate-reactive group selected from a hydroxyl group, a mercapto group, and an amino group. However, it has been noted that such compositions exhibit insufficient adhesion to aluminum.

[0012] HENKEL's PCT application, International Publication No. 2019 / 109328, describes a moisture-curing hot-melt adhesive composition comprising an ethylenically unsaturated carboxylic acid graft-modified polymer in addition to a silane-modified polymer and a tackifier. This application does not refer to adhesion to metal substrates, particularly aluminum.

[0013] Therefore, there is still a need for silane-modified APAO-based adhesive compositions that have improved adhesion to metal substrates, preferably aluminum substrates. [Overview of the project]

[0014] The present invention relates to a moisture-curing silylated adhesive composition, and based on the total weight of the composition, -20% to 50% by weight of at least one silane-modified amorphous poly-α-olefin (or APAO)(A), -2% to 15% by weight of an expanded hollow thermoplastic polymer microsphere, and at least one filler (B) consisting of expanded hollow thermoplastic polymer microspheres, -10% to 60% by weight of at least one tackifier (C), Includes.

[0015] Unless otherwise specified, percentages used herein to express the amounts of components of the compositions according to the present invention correspond to weight / weight percentage.

[0016] Unexpectedly, it was found that the moisture-curable silylated adhesive compositions defined above also exhibit advantageously high levels of adhesion to metal substrates, particularly aluminum substrates, after curing with moisture.

[0017] Such a high level of adhesion can be experimentally inferred from the failure mode of an assembly consisting of two aluminum plates joined on a bonding region by the cured composition, in tests in which the adhesive joint present on the bonding region of the assembly is subjected to shear stress. In fact, in the field of adhesives, several types of failure can be distinguished in tensile and / or shear tests, as follows: - Cohesive failure (often expressed as 100% CF) occurs within the actual layer of the adhesive joint where each of the two substrate bonding regions has a fraction of adhesive. - Adhesive failure that occurs at the adhesive / substrate contact surface, where no adhesive remains on one of the two substrate bonding areas (often indicated as 100% AF).

[0018] There are also many intermediate situations corresponding to the mixing of two failure modes evaluated by calculating the parts of the agglomeration failure region and the adhesion failure region.

[0019] Here, it has been found that the above two aluminum plate assemblies advantageously exhibit 100% agglomeration failure or at least 50% CF in a shear test.

[0020] In addition to its high adhesion quality to the aluminum substrate, the corresponding adhesive joints also exhibit advantageous agglomeration characteristics, which can be observed by measuring the stress corresponding to the failure (or fracture or rupture) of the above two aluminum plate assemblies.

[0021] Therefore, the moisture-curable silylated adhesive composition according to the present invention is well-suited for use aimed at assembling metal substrates, more preferably aluminum substrates.

[0022] Silane-modified amorphous poly-α-olefin (A): The moisture-curable silylated adhesive composition according to the present invention contains at least one silane-modified amorphous poly-α-olefin (A).

[0023] The term "α-olefin" refers to an alkene of the formula C H 2n (where n corresponds to the number of carbon atoms). Examples of α-olefins include ethylene, propylene, 1-butene, 2-methyl-1-propene (isobutylene), 1-pentene, 1-hexene, 1-heptene, and 1-octene.

[0024] The term "poly-α-olefin" refers to homopolymers and copolymers obtained by polymerization or oligomerization of one or more α-olefins.

[0025] Particularly useful silane-modified poly-α-olefins are either completely amorphous or have a low level of crystallinity. In one embodiment, the crystallinity is about 25% or less when determined by X-ray diffraction.

[0026] According to a preferred embodiment, the silane-modified amorphous poly-α-olefin (A) contains at least one, preferably two alkoxysilyl groups of formula (I), -Si(R 1 ) p (OR 2 ) 3-p (I) wherein, -R 1 represents a linear or branched alkyl radical containing 1 to 4 carbon atoms, and when several radicals R 1 are present, these radicals can be the same or different, -R 2 represents a linear or branched alkyl radical containing 1 to 4 carbon atoms, and when several radicals R 2 are present, these radicals can be the same or different, and two groups OR 2 can be engaged in the same ring, -p is an integer equal to 0, 1 or 2, preferably equal to 0 or 1.

[0027] Such alkoxysilyl groups containing poly-α-olefins are known to those skilled in the art and can be produced, for example, by grafting an unsaturated silane such as vinyl-trimethoxysilane onto a poly-α-olefin obtained by Ziegler-Natta catalytic polymerization or metallocene catalytic polymerization.

[0028] Suitable alkoxysilyl groups containing poly-α-olefins include silane graft homopolymers, copolymers, and monomer terpolymers selected from the group consisting of ethylene, propylene, 1-butene, and higher α-olefins. Particularly preferred alkoxysilyl groups containing poly-α-olefins include silane graft homopolymers of propylene, silane graft copolymers of propylene and ethylene, silane graft copolymers of propylene and 1-butene or other higher α-olefins, and silane graft terpolymers of ethylene, propylene, and 1-butene. Preferably, the poly-α-olefin containing at least one alkoxysilyl group is a silane graft atactic poly-α-olefin, particularly a silane graft amorphous poly-α-olefin (APAO).

[0029] Amorphous poly-α-olefins are commercially available. For example, amorphous poly-α-olefins based on ethylene, propylene, and 1-butene can be obtained from EVONIK's VESTOPLAST® product line, which includes a silane-modified amorphous poly-α-olefin grade called VESTOPLAST® 206.

[0030] Filler (B): The moisture-curable silylated adhesive composition according to the present invention comprises at least one filler (B) consisting of expanded hollow thermoplastic polymer microspheres.

[0031] Expandable thermoplastic polymer microspheres comprise a thermoplastic polymer shell and a foaming agent encapsulated within it. When such expandable microspheres are heated at a temperature high enough to induce a sufficient degree of expansion over a certain period of time, expanded hollow thermoplastic polymer microspheres are obtained.

[0032] According to a preferred embodiment, the filler (B) comprises expanded hollow thermoplastic polymer microspheres coated with colloidal calcium carbonate. Such microspheres are known and disclosed in U.S. Patent No. 6,225,361. The expanded thermoplastic polymer microspheres are mixed with colloidal calcium carbonate to provide composite beads having a hollow expanded thermoplastic polymer microsphere shell and colloidal calcium carbonate deposited on its surface.

[0033] Such fillers are also commercially available as anhydrous, flowable products, for example, under the name EMC Organic-inorganic hybrid filler from Japan Fillite Co. Ltd.

[0034] Tackifier (C): The moisture-curable silylated adhesive composition according to the present invention comprises at least one tackifier (C).

[0035] The tackifying resin (C) is preferably selected from the following categories. (a) Natural and modified rosins such as gum rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin and polymerized rosin; (b) For example, glycerol and pentaerythritol esters of natural rosins and modified rosins such as glycerol ester of wood rosin, glycerol ester of hydrogenated rosin, glycerol ester of polymerized rosin, pentaerythritol ester of wood rosin, pentaerythritol ester of hydrogenated rosin, pentaerythritol ester of tall oil rosin, and phenol-modified pentaerythritol ester of rosin; (c) Polyterpene resins including hydrogenated polyterpene resins having a ring-and-ball softening point of approximately 20°C to 140°C, wherein the latter polyterpene resins are generally produced from the polymerization of terpene hydrocarbons such as monoterpenes known as pinene in the presence of a Friedel-Crafts catalyst at a moderately low temperature; (d) Phenolic terpene resins, such as those produced by the condensation of terpenes and phenols in an acidic medium; (e) an aliphatic (including alicyclic) petroleum hydrocarbon resin (C5) having a ring-and-ball softening point of approximately 60°C to 140°C, wherein the aliphatic (including alicyclic) petroleum hydrocarbon resin (C5) is obtained from polymerization of C5-hydrocarbon monomers, and the corresponding hydrogenated derivative is obtained from the subsequent whole or partial hydrogenation thereof; (f) Aromatic petroleum hydrocarbon resins (C9) having a ring-and-ball softening point of approximately 60°C to 140°C, which are produced by polymerization of C9-hydrocarbon monomers; and corresponding hydrogenated derivatives produced therefrom by whole or partial hydrogenation thereof; (g) Aliphatic (including alicyclic) and / or aromatic petroleum resins (C5 / C9) having a ring-and-ball softening point of approximately 60°C to 140°C, which are obtained from the polymerization of C5 / C9 hydrocarbon monomers; and corresponding hydrogenated derivatives obtained from the subsequent whole or partial hydrogenation thereof; (h) Silane derivatives of C5 resins, C9 resins and C5 / C9 resin mixtures as defined by classes (e), (f) and (g) above, by thermal polymerization of a composition comprising a silane and monomers, comprising a cyclic olefin having at least one ethylenically unsaturated group selected from the C5 fraction, the C9 fraction and dicyclopentadiene of naphtha cracking. Such silane derivatives are disclosed, for example, in European Patent No. 3176191.

[0036] According to a more preferred embodiment, the tackifying resin (C) is selected from among the silane derivatives of category (h).

[0037] Examples of C5 hydrocarbon monomers useful for preparing tackifying resins belonging to class (e) or (g) include trans-1,3-pentadiene, cis-1,3-pentadiene, 2-methyl-2-butene, dicyclopentadiene, cyclopentadiene, cyclopentene, and any mixture thereof.

[0038] Examples of C9 hydrocarbon monomers useful for preparing tackifying resins belonging to class (f) or (g) include vinyltoluene, dicyclopentadiene, indene, methylstyrene, styrene, methylindene, and any mixture thereof.

[0039] According to a particular embodiment of the present invention, a mixture of two or more of the above-mentioned tackifying resins is used in the hot-melt adhesive composition according to the present invention.

[0040] The tackifying resin(s) (C) used in accordance with the present invention is commercially available.

[0041] Examples of commercially available tackifying resins (C) belonging to class (a) include the following: -Unmodified natural tall oil rosin sold by Kraton Company under the trade names SYLVAROS (registered trademark) (85, 90 and NCY), - Partially hydrogenated rosin sold by EASTMAN Company under the product name FORALYN(registered trademark)E, and fully hydrogenated rosin sold by Eastman under the product name FORAL(registered trademark)AX-E, - A dimerized rosin sold by EASTMAN Company under the product name DYMEREX (registered trademark).

[0042] Examples of commercially available tackifying resins (C) belonging to class (b) include the following: Both are available from Kraton Company. -SYLVALITE(registered trademark) RE 100L, which is a pentaerythritol-based tall oil rosin ester, and - SYLVALITE(registered trademark) RE 85L, a glycerol ester of tall oil rosin.

[0043] Examples of commercially available tackifying resins (C) belonging to class (c) include the following: -Polyterpene tackifiers sold by KRATON Company under the product names SYLVAGUM®TR and SYLVARES®TR series (7115, 7125, A25L, B115, M1115).

[0044] Examples of commercially available tackifying resins (C) belonging to class (d) include the following: -Terpene phenol resins manufactured by KRATON Company and sold under the trade names SYLVARES(registered trademark)TP(96, 2040, 300, 7042, 2019).

[0045] Examples of commercially available tackifying resins (plural) (C) belonging to class (e) include the following: -Aliphatic and alicyclic petroleum hydrocarbon resins based on C5 petroleum hydrocarbon fractions (such as mixtures of trans-1,3-pentadiene, cis-1,3-pentadiene, 2-methyl-2-butene, dicyclopentadiene, cyclopentadiene, and cyclopentene), having a ring-and-ball softening point in the range of 60°C to 140°C, sold by Eastman Company under the trade names WINGTACK® 98 and WINGTACK® ET, and sold by Exxonmobile under the trade name ESCOREZ® 1310LC, - Partially aliphatic and alicyclic petroleum hydrocarbon resins based on C5 petroleum hydrocarbon fractions (such as a mixture of trans-1,3-pentadiene, cis-1,3-pentadiene, 2-methyl-2-butene, dicyclopentadiene, cyclopentadiene, and cyclopentene), which have a ring-and-ball softening point in the range of 80°C to 140°C, and are sold by KOLON Company under the product names SUKOREZ® SU210 and SUKOREZ® 230. The softening point of SUKOREZ® SU210 is 110°C. - A fully hydrogenated alicyclic petroleum hydrocarbon resin based on the dicyclopentadiene-petroleum hydrocarbon fraction, sold under the product names ESCOREZ® 5400 series (5400, 5415, 5490), with a ring-and-ball softening point in the range of 60°C to 140°C, from EXXONMOBIL. The softening point of ESCOREZ® 5400 is 100°C.

[0046] Examples of commercially available tackifying resins (C) belonging to class (f) may be mentioned below. - Aromatic petroleum hydrocarbon resins based on C9 hydrocarbon petroleum fractions (such as a mixture of vinyltoluene, dicyclopentadiene, indene, methylstyrene, styrene, and methylindene), available from KOLON INDUSTRIES under the trade name HIKOTACK (registered trademark) (P-90, P110 S, and P120 S), with a ring-and-ball softening point of approximately 60°C to 140°C.

[0047] Examples of commercially available tackifying resins (plural) (C) belonging to class (g) may be mentioned below. - Partially hydrogenated alicyclic-modified aromatic petroleum hydrocarbon resins based on C5 / C9 hydrocarbon petroleum fractions, sold under the product names ESCOREZ® 5600 series (5600, 5615, 5690) by EXXONMOBIL Company, with a ring-and-ball softening point of approximately 60°C to 140°C. The softening point of ESCOREZ® 5600 is 100°C. A non-hydrogenated aliphatic-modified aromatic hydrocarbon petroleum resin based on a C5 / C9 hydrocarbon petroleum fraction, sold by ZEON under the trade name QUINTONE® DX390N, with a softening point of -93°C.

[0048] Examples of commercially available tackifying resins (C) belonging to class (h) include silane resins (plural) available from KOLON INDUSTRIES, sold under the trade names HRR® (100, A100, and 120).

[0049] HRR(registered trademark)-100 and HRR(registered trademark)-A100 have a ring-and-ball softening point of 100°C. HRR(registered trademark)-120 has a ring-and-ball softening point of 120°C.

[0050] According to a preferred embodiment, the ring-and-ball (or softening point) of the tackifying resin (or multiple resins) (C) is preferably in the range of 90°C to 125°C, and more preferably in the range of 90°C to 115°C.

[0051] The softening temperature (or point) is determined according to the standardized ASTM E28 test, the principle of which is as follows: A brass ring with a diameter of approximately 2 cm is filled with the molten resin of the test. After cooling to room temperature, the ring and solid resin are placed horizontally in a thermostat-controlled glycerol bath in which the temperature can change by 5°C per minute. A steel ball with a diameter of approximately 9.5 mm is placed in the center of the solid resin disc. The softening temperature is the temperature at which the resin disc flows by a volume of 25.4 mm under the weight of the ball while the bath temperature is increased at a rate of 5°C / min.

[0052] According to a particularly preferred embodiment, the moisture-curable silylated adhesive composition according to the present invention is, based on the total weight of the composition, -30% to 40% by weight of at least one silane-modified APAO(A); -3% to 10% by weight of at least one filler (B); and -20% to 40% by weight of at least one tackifier (C) Includes.

[0053] Optional ingredients: The moisture-curable silylated adhesive composition according to the present invention may contain, in addition to the silane-modified APAO(A), at least one additional thermoplastic polymer (D) that does not contain any alkoxysilyl groups.

[0054] Preferably, such polymer (D) is selected from among styrene block copolymers (SBCs).

[0055] The useful styrene block copolymers according to the present invention include linear or radial block copolymers comprising at least one non-elastomer block A, which is a polystyrene block, and at least one elastomer block B, which is a diene polymer block that is fully or partially hydrogenated or unhydrogenated.

[0056] In particular, the styrene block copolymer according to the present invention is the following copolymer: - A linear diblock copolymer with an AB structure, -A linear triblock copolymer with an ABA structure, -(AB)nY structure radial block copolymer and mixtures thereof may be selected. During the ceremony, -A is a non-elastomer polystyrene block, -B is an elastomeric diene block polymer such as polybutadiene or polyisoprene block. -Y is a polyvalent compound, -n is an integer of at least 3.

[0057] ABA-structured linear triblock copolymers can be used alone or in combination with AB-structured linear diblock copolymers.

[0058] Elastomer block B may be post-treated by partial or complete hydrogenation to improve its thermal stability.

[0059] Preferably, the useful styrene block copolymer according to the present invention is selected from the following linear triblock copolymers. -Styrene-butadiene diblock (SB) or styrene-butadiene-styrene copolymer (SBS) containing or not containing styrene-butadiene diblock (SB), -Styrene-isoprene-styrene copolymer (SIS) containing or not containing styrene-isoprene block (SI), -Styrene-ethylene-butylene-styrene copolymer (SEBS), -Styrene-butadiene-butylene-styrene copolymer (SBBS), Styrene-ethylene-propylene-styrene copolymer (SEPS), -and any mixture thereof.

[0060] More preferably, the styrene block copolymer is a linear triblock copolymer of the ABA structure defined above, and even more preferably, a linear SEBS triblock copolymer according to a more preferred embodiment.

[0061] When the styrene block copolymer is a mixture of a linear triblock copolymer with an ABA structure and a linear diblock copolymer with an AB structure as defined above, the linear diblock content is preferably in the range of 1 to 70% by weight relative to the total weight of the mixture of triblocks and diblocks.

[0062] The amount of terminal block A in the linear triblock copolymer of the ABA structure as defined above may be in the range of 14 to 51% by weight, preferably 20 to 40% by weight, relative to the total weight of the linear triblock copolymer of the ABA structure, or, in the case of a mixture of linear triblock copolymers and diblock copolymers of the ABA and AB structures, relative to the total weight of the mixture of triblocks and diblocks.

[0063] Useful commercially available styrene block copolymers include the KRATON D and G® series from KRATON POLYMERS, the EUROPRENE Sol T® series from VERSALIS (ENI group), the SOLPRENE® series from DYNASOL ELASTOMERS, and the TAIPOL® and VECTOR® series from TSRC Corporation.

[0064] Examples of useful specific styrene block copolymers include the following: - A transparent linear triblock copolymer based on styrene and ethylene / butylene, with a polystyrene content of 20%, an average molecular weight of approximately 110,000 g / mol, an MFI (measured according to ASTMD1238) of 19 g / 10 min (mn) at 230°C and a load of 2.16 kg, and an SEB diblock content of approximately 7% by weight relative to the total weight of the mixture, KRATON® G1643V. - A mixture of linear SBS triblock and SB diblock copolymer, having a styrene content of 29.5% by weight relative to the total weight of the mixture, an average molecular weight of approximately 122,000 g / mol, an MFI of 8.5 g / 10 min (mn) at 200°C under a load of 5 kg (1 kg) (measured according to ISO 1133), and an SB diblock content of approximately 17% by weight relative to the total weight of the mixture, KRATON® D1152 ES. KRATON® D1161 is a mixture of linear SIS triblock and SI diblock copolymers, having a styrene content of 15% by weight relative to the total weight of the mixture, an MFI of 9 g / 10 mn at 200°C under a 5 kg load (measured according to ISO 1133), an average molecular weight of approximately 220,000 g / mol, and an SI diblock content of approximately 19% by weight relative to the total weight of the mixture. TAIPOL® SBS4202, manufactured by TSRC Corporation, is a linear SBS triblock copolymer with a styrene content of 40% by weight relative to the total weight of the triblock copolymer, an SB diblock content of less than 1%, an MFI of 3-10 g / 10 mn (measured according to ASTMD1238) at 190°C under a 5 kg load, and an average molecular weight of approximately 102,400 g / mol. VECTOR® 4411, manufactured by TSRC Corporation, is a linear SIS triblock copolymer with a styrene content of 44% by weight relative to the total weight of the triblock copolymer, an SI diblock content of less than 1%, an MFI of 40 g / 10 mn at 200°C under a 5 kg load (measured according to ASTM D1238), and an average molecular weight of approximately 106,000 g / mol.

[0065] Preferably, the styrene block copolymer (D) is present in the composition according to the present invention in an amount ranging from 4% to 16% by weight, more preferably 8% to 12%, based on the total weight of the composition.

[0066] The moisture-curable silylated adhesive composition according to the present invention may also optionally contain at least one silane-functionalized polyolefin wax (E). A suitable silane-functionalized polyolefin wax is produced by grafting silane onto a polyolefin wax. Preferred silane-functionalized polyolefin waxes include waxes of ethylene and propylene homopolymers or copolymers grafted with silane, particularly polypropylene or polyethylene waxes grafted with silane.

[0067] Such silane-functionalized waxes are commercially available, for example, under the name Licocene® PP SI 1362, a silane-modified polypropylene wax, from Clariant.

[0068] The amount of at least one silane-functionalized polyolefin wax in the adhesive composition is not particularly limited. The at least one silane-functionalized polyolefin wax may be present in the adhesive composition in an amount of at least 1.0% by weight, particularly at least 2.5% by weight, based on the total weight of the adhesive composition. Preferably, the at least one silane-functionalized polyolefin wax is present in the adhesive composition in an amount of 1.0 to 30.0% by weight, preferably 2.5 to 20.0% by weight, and more preferably 8.0 to 17.0% by weight, based on the total weight of the adhesive composition.

[0069] The moisture-curable silylated adhesive composition according to the present invention may also optionally contain at least one plasticizer (F) selected from naphthenic oil, paraffin oil, vegetable oil, polyisobutylene, benzoate ester, non-silane functionalized wax, and acrylic acid or carboxylic acid modified wax.

[0070] Plasticizers (multiple) (F) can impart good processability to the hot melt adhesive composition. Furthermore, plasticizers (multiple) (F) can also provide desired viscosity control without substantially reducing the adhesive strength or supply temperature (operating temperature) of the hot melt adhesive.

[0071] Naphthenic oils and paraffinic oils are petroleum-based oils consisting of a mixture of naphthenic hydrocarbons (aliphatic, saturated or unsaturated, C4-C7 membered hydrocarbon rings, preferably aliphatic, saturated or unsaturated, C4-C6 membered rings). Examples include cycloalkanes such as cyclopentane, cyclohexane, and cycloheptane, paraffinic hydrocarbons (saturated, linear or branched alkanes), and aromatic hydrocarbons (aromatic hydrocarbon rings that may be monocyclic or polycyclic, preferably aromatic C6 membered hydrocarbon rings).

[0072] The classification of naphthenic oils and paraffinic oils is based on the amount of each type of hydrocarbon in the oil. Typically, paraffinic oils have a paraffinic hydrocarbon content of at least 50% by weight, while naphthenic oils have a naphthenic hydrocarbon content of 30% to 40% by weight relative to the total weight of the plasticizer.

[0073] Preferably, the plasticizer(s)(F) contained in the composition according to the present invention is a vegetable oil, preferably an epoxidized vegetable oil, and most preferably an epoxidized linseed oil.

[0074] Useful plasticizers (F) are commercially available. Examples include: - Naphthenic oil from NYNAS sold under the product names NYFLEX® 223 and NYFLEX® 222B; - Epoxy linseed oil from ARKEMA under the product name VIKOFLEX (registered trademark) 7190.

[0075] Preferably, the plasticizer (F) is present in the composition according to the present invention in an amount ranging from 1% to 20% by weight, preferably 4% to 10%, based on the total weight of the composition.

[0076] The moisture-curable silylated adhesive composition according to the present invention may also optionally contain at least one moisture-scavenging agent and / or one adhesion promoter.

[0077] To prevent immediate crosslinking of silane-modified amorphous poly-α-olefin (A) and to increase the viscosity of the adhesive composition during storage, it is preferable to monitor the water content of the composition according to the present invention. Moisture can be introduced into the composition by a portion of its components.

[0078] For this reason, compositions according to the present invention may contain one or more dehydrating agents (or moisture scavengers). Suitable dehydrating agents are alkoxysilanes such as trialkoxysilanes (especially trimethoxysilanes) and alkoxysilanes containing amino, mercapto, epoxy, or isocyanurate groups. Examples include vinyltrimethoxysilane (or VTMO), γ-glycidyloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, aminopropyltrimethoxysilane, or trimethoxymethylsilane.

[0079] Some of these compounds can also act as adhesion promoters, particularly trialksoxysilanes containing amino, mercapto, epoxy, or isocyanurate groups, such as [3-(2-aminoethyl)aminopropyl]trimethoxysilane (also known as DAMO) or tris(3-trimethoxysilylpropyl)isocyanurate.

[0080] Many moisture-absorbing and adhesion-promoting agents are commercially available. For example, tris(3-trimethoxysilylpropyl) isocyanurate is available from EVONIK under the name Dynasylan® 7163.

[0081] According to a preferred embodiment, the composition may contain 0.1 to 2% by weight of a moisture scavenger and 0.5 to 5% by weight of an adhesion promoter, based on the total weight of the hot melt adhesive composition.

[0082] The moisture-curable silylated adhesive composition according to the present invention may also preferably contain at least one antioxidant in an amount of 0.1% to 2% by weight relative to the total weight of the hot-melt adhesive composition.

[0083] Antioxidants useful in the present invention are preferably incorporated into the hot-melt adhesive composition to help protect it from chemical decomposition. Such decomposition generally involves the reaction of free radicals with dioxygen resulting from chain severance catalyzed by either ultraviolet light or heat. Such decomposition usually manifests as deterioration of the appearance (browning of color) or other physical properties of the adhesive, and the performance characteristics of the adhesive.

[0084] In particular, antioxidants(s) protect the hot-melt adhesive composition and its components from the effects of thermal decomposition reactions that primarily occur during the manufacturing and application processes of adhesives, where the adhesive is heated at high temperatures for extended periods in the presence of oxygen.

[0085] Useful antioxidants include hindered phenols and sulfur and phosphorus-containing phenols. Hindered phenols are well known to those skilled in the art and can be characterized as phenol compounds that also contain sterically bulky groups adjacent to their phenolic hydroxyl groups. In particular, tertiary butyl groups are generally substituted on the benzene ring at least one ortho position relative to the phenolic hydroxyl group.

[0086] Representative hindered phenols include the following: 1,3,5-Trimethyl-1-2,4,6-Tris(3-5-di-tert-butyl-4-hydroxybenzyl)benzene; Pentaerythritol tetrakis-3 (3,5-di-tert-butyl 1-4-hydroxyphenyl)propionate; n-octadecyl-3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; 4,4'-Methylenebis(4-methyl-6-tert-butylphenol); 4,4'-thiobis(6-tert-butyl-o-cresol); 2,6-di-tert-butylphenol; 6-(4-hydroxyphenoxy)-2,4-bis(n-octylthio)-1,3,5-triazine; 2,4,6-Tris(4-hydroxy-3,5-di-tert-butyl-phenoxy)-1,3,5-triazine; di-n-octadecyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate; 2-(n-octylthio)ethyl-3,5-di-tert-butyl-4-hydroxybenzoate; Sorbitol hexa-(3,3,5-di-tert-butyl-4-hydroxyphenyl)propionate; 2,2'-Methylenebis(4-methyl-6-tert-butylphenol) phosphites (e.g., including tris-(p-nonylphenyl)-phosphite (TNPP) and bis(2,4-di-tert-butylphenyl)4,4'-diphenylene-diphosphonite, di-stearyl-3,3'-thiodipropionate (DSTDP)); Tetrakis(methylene(3,5-di-ter-butyl-4-hydroxyhydrocinnamate))methane; (Tris(2,4-di-tert-butylphenyl)phosphate) and combinations thereof.

[0087] Hindered phenol antioxidants can be used alone or in combination with other antioxidants, such as phosphite antioxidants like the IRGAFOS® series or aromatic amine antioxidants like ADDIVANT's NAUGARD® series.

[0088] Useful antioxidants are commercially available under various brand names, such as the hindered phenol antioxidants in BASF's IRGANOX® series, including IRGANOX® 1010 (tetrakis(methylene(3,5-di-ter-butyl-4-hydroxyhydrocinnamate))methane) and IRGAFOS® 168 antioxidant (tris(2,4-di-tert-butylphenyl)phosphate).

[0089] The total amount of antioxidants(s) is preferably in the range of 0.1 to 3% by weight, more preferably 0.5% to 1% by weight, relative to the total weight of the hot melt adhesive composition.

[0090] The moisture-curable silylated adhesive composition according to the present invention may also preferably contain at least one curing catalyst, which may be any catalyst known to those skilled in the art for silanol condensation. Examples of such catalysts include amines or organometallic derivatives, particularly organic derivatives of iron, titanium, aluminum, or divalent or tetravalent tin, such as dibutylsuturnate (DBTL).

[0091] The amount of curing catalyst by weight is typically in the range of 0.1–2%.

[0092] The moisture-curable composition according to the present invention can be prepared by mixing a silane-modified amorphous poly-α-olefin (A) and a filler (B) at a temperature of 120°C to 180°C and a relative humidity of 0.1% to 50%. If a catalyst is present, it is preferably added in a second step after mixing the silane-modified APAO (A) and the filler (B). Other components are introduced according to conventional practice.

[0093] The present invention also relates to the use of the moisture-curable silylated adhesive composition according to the present invention as an assembly adhesive or laminating adhesive in the transportation and electronics industries, preferably the automotive industry.

[0094] The present invention also relates to a method for manufacturing assembled products, - Step (i) of heating the moisture-curing silylated adhesive composition according to the present invention at a temperature in the range of 130°C to 180°C for a sufficiently long time to make the composition liquid enough to be applied to a substrate, and then - A step (ii) of coating the composition onto the surface of a primary substrate, and then - A step (iii) of bringing the coated surface of the primary substrate into contact with the surface of the secondary substrate, and then - A step (iv) of chemically curing the coated composition with water, preferably with atmospheric moisture, Includes.

[0095] The adhesive composition can be applied to the surface of a primary substrate using any conventional technique such as slot die coating, roller coating, extrusion coating, or spray coating.

[0096] The amount of adhesive coated on a surface unit basis of the primary substrate varies from 50 to 500 g / m², depending on the substrate to be bonded. 2 Preferably 65-300 g / m² 2 It can vary over a very wide range.

[0097] The primary and secondary substrates may have different or the same properties and can be composed of any conventional material, including polypropylene, polyethylene, ABS, PMMA, and metal substrates.

[0098] In a more preferred embodiment, at least one of the primary substrate and the secondary substrate is aluminum.

[0099] This application relates to an assembled product comprising at least two substrates bonded together by at least one cured silylated adhesive composition according to the present invention.

[0100] The substrate to be bonded may be selected from among the substrates listed above in the method according to the present invention.

[0101] In a particular embodiment of the present invention, the assembled product according to the present invention may be a multilayer product comprising at least two substrates bonded together by at least one cured silylated adhesive composition according to the present invention. [Examples]

[0102] The following embodiments are given purely to illustrate the present invention and should not be construed as limiting its scope.

[0103] Example 1: Moisture-curing silylated adhesive composition based on APAO (A), filler (B), and tackifier (C) 1) Preparation: The composition of Example 1 is prepared by mixing the components indicated in Table 1, as previously disclosed.

[0104] After preparation, the composition is stored in a sealed cartridge and then subjected to the following tests.

[0105] 2) Destructive testing of an assembly consisting of two aluminum plates joined by a hardened composition over a bonding region: Use two rectangular aluminum plates measuring 100mm x 25mm. After cleaning the two plates with ethanol, define a rectangular joining area measuring 12.5mm x 25mm at one end of each plate (using adhesive tape).

[0106] The adhesive composition prepared above is heated at 150°C for 1 hour, then applied to the bonding region of aluminum plate 1, and then quickly placed on top of the bonding region of aluminum plate 2 to create a shear test specimen in which the free portions of the two aluminum plates extend from both sides of the bonding region to the opposite side.

[0107] The thickness of the adhesive composition between the two aluminum plates is 2 mm, controlled by a 2 mm spacer.

[0108] The shear test specimens are placed in a 120°C oven for 5 minutes, and then in a 23°C / 50%RH conditioning room for 7 days to allow them to harden.

[0109] After hardening, both ends of the shear test specimen are pulled in a tensile machine at a constant speed equal to 10 mm / min until the specimen breaks (or bursts).

[0110] The corresponding stress (or fracture stress) is recorded and shown in Table 1.

[0111] To determine the fracture mode, the binding regions of each plate were observed. 50% cohesive fracture was observed and is shown as 50%CF in Table 1.

[0112] Examples 2-4: Moisture-curing silylated adhesive composition based on APAO (A), filler (B), and tackifier (C): The procedure in Example 1 was repeated using the compositions shown in Table 1. Then, the same test as in Example 1 was performed. The results are shown in Table 1.

[0113] Examples A and B (comparison): Moisture-curing silylated adhesive composition based on APAO (A) and filler (B)-free tackifier (C) The procedure in Example 1 was repeated using the compositions shown in Table 1. Then, the same test as in Example 1 was performed. The results are shown in Table 1.

[0114] Examples 1-4 in Table 1, in contrast to Examples A and B, clearly demonstrate a shear failure mode of at least 50% of CF, indicating significantly improved adhesion to the aluminum substrate, along with proper aggregation of the adhesive joint made of the cured composition. TIFF0007897849000001.tif124170

Claims

1. A moisture-curing silylated adhesive composition, wherein based on the total weight of the composition, -20% to 50% by weight of at least one silane-modified amorphous poly-α-olefin (or APAO) (A), - At least one filler (B) consisting of expanded hollow thermoplastic resin polymer microspheres in an amount of -2% to 15% by weight, -10% to 60% by weight of at least one tackifier (C), A moisture-curing silylated adhesive composition containing the following:

2. A silane-modified amorphous poly-α-olefin (A) comprises at least one alkoxysilyl group of formula (I), -Si(R １ ) ｐ (OR ２ ) ３－ｐ (I) During the ceremony, -R １ R represents a linear or branched alkyl radical containing 1 to 4 carbon atoms, and several radicals R １ If present, these radicals may be the same or different. -R ２ represents a linear or branched alkyl radical containing 1 to 4 carbon atoms, and when several radicals R ２ are present, these radicals may be the same or different, and there is a possibility that two groups OR ２ may be engaged in the same ring, -p is an integer equal to 0, 1, or 2. A moisture-curable silylated adhesive composition according to claim 1, characterized in that...

3. The moisture-curable silylated adhesive composition according to claim 1 or 2, characterized in that the filler (B) consists of expanded hollow thermoplastic resin polymer microspheres coated with colloidal calcium carbonate.

4. A moisture-curable silylated adhesive composition according to any one of claims 1 to 3, characterized in that the tackifier (C) is selected from silane derivatives of C5 resin, C9 resin, and mixtures of C5 / C9 resin, and the tackifier (C) is produced from the thermal polymerization of a composition containing silane and monomer, wherein the monomer contains a cyclic olefin having at least one ethylenically unsaturated group selected from C5 fraction, C9 fraction, and naphtha-decomposed dicyclopentadiene.

5. A moisture-curable silylated adhesive composition according to any one of claims 1 to 4, characterized in that the softening point of the tackifying resin (or multiple resins) (C) is in the range of 90°C to 115°C.

6. Based on the total weight of the aforementioned composition, -30% to 40% by weight of at least one silane-modified APAO(A), -3% to 10% by weight of at least one filler (B), - At least one tackifier (C) in an amount of -20% to 40% by weight, A moisture-curing silylated adhesive composition according to any one of claims 1 to 5, characterized by containing the following:

7. A moisture-curable silylated adhesive composition according to any one of claims 1 to 6, characterized by comprising at least one additional thermoplastic resin polymer (D) that does not contain any alkoxysilyl groups.

8. The moisture-curable silylated adhesive composition according to claim 7, characterized in that at least one additional thermoplastic resin polymer (D) is selected from among styrene block copolymers (SBCs).

9. The moisture-curable silylated adhesive composition according to claim 7 or 8, characterized in that at least one additional thermoplastic resin polymer (D) is a linear SEBS triblock copolymer.

10. A moisture-curable silylated adhesive composition according to any one of claims 1 to 9, characterized by comprising at least one silane-functionalized polyolefin wax (E).

11. A moisture-curable silylated adhesive composition according to any one of claims 1 to 10, characterized by comprising at least one plasticizer (F) which can be selected from naphthenic oil, paraffin oil, vegetable oil, polyisobutylene, benzoate ester, non-silane functionalized wax, and acrylic acid or carboxylic acid modified wax.

12. Use of the moisture-curing silylated adhesive composition according to any one of claims 1 to 11 as an assembly adhesive or laminating adhesive in the transportation and electronics industries.

13. A method for manufacturing assembled products, - Step (i) of heating the moisture-curable silylated adhesive composition according to any one of claims 1 to 11 at a temperature in the range of 130°C to 180°C for a sufficiently long time to make the composition liquid enough to be applied to a substrate, and then - A step (ii) of coating the surface of the primary substrate with the composition, and then - A step (iii) of bringing the coated surface of the primary substrate into contact with the surface of the secondary substrate, and then - A step (iv) in which the coated composition is chemically cured with water, A method for manufacturing assembled products, including the production of such products.

14. A method for manufacturing the assembled product according to claim 13, characterized in that at least one of the primary substrate and the secondary substrate is aluminum.

15. An assembled product comprising at least two substrates bonded together by at least one cured silylated adhesive composition as defined in any one of claims 1 to 11.

Images