阅读说明：本技术 阻燃粘合剂组合物 (Flame retardant adhesive composition ) 是由 孙春雨 陈瑾茜 杨玉衡 陆琤 邱雪宇 武豪 于 2019-02-18 设计创作，主要内容包括：提供了一种粘合剂组合物,更具体地提供了一种用于电气器件的(甲基)丙烯酸类粘合剂组合物,例如其具有改进的粘合强度,热传导性以及阻燃性。(Provided is an adhesive composition, more specifically a (meth) acrylic adhesive composition for electrical devices, for example, having improved adhesive strength, thermal conductivity, and flame retardancy.)

1. An adhesive composition comprising:

a) an ethylenically unsaturated monomer, wherein the ethylenically unsaturated monomer,

b) an elastomer of a polymer, the elastomer being a polymer,

c) an initiator, wherein the initiator is selected from the group consisting of,

d) a liquid rubber terminated with a vinyl group,

e) a thermally conductive filler, and

f) a diorganophosphinate.

2. The adhesive composition of claim 1 wherein the ethylenically unsaturated monomer is selected from the group consisting of (meth) acrylates, N-t-butylacrylamide, (meth) acrylic acid, 2-ethylhexyl (meth) acrylate, and mixtures thereof.

3. The adhesive composition of claim 1 wherein the polymeric elastomer is selected from the group consisting of core shell polymers, block copolymer rubbers and mixtures thereof.

4. The adhesive composition of claim 1 wherein the vinyl terminated liquid rubber is selected from the group consisting of methacrylate terminated polybutadiene, acrylate terminated polybutadiene, methacrylate terminated polybutadiene-acrylonitrile copolymer, acrylate terminated polybutadiene-acrylonitrile copolymer, and mixtures thereof.

5. The adhesive composition of claim 1 wherein the vinyl terminated liquid rubber is selected from the group consisting of methacrylate terminated polybutadiene, acrylate terminated polybutadiene and mixtures thereof.

6. The adhesive composition of claim 1, wherein the thermally conductive filler is selected from the group consisting of metal hydroxides, metal oxides, metals, ceramics, and mixtures thereof.

7. The adhesive composition of claim 1, wherein the diorganophosphinate salt is selected from the group consisting of aluminum tris (diethylphosphinate), ammonium tris (diethylphosphinate), aluminum tris (methylethylphosphinate), aluminum tris (diphenylphosphinate), zinc bis (diethylphosphinate), zinc bis (methylethylphosphinate), zinc bis (diphenylphosphinate), titanyl bis (diethylphosphinate), titanium tetrakis (diethylphosphinate), titanyl bis (methylethylphosphinate), titanium tetrakis (methylethylphosphinate), titanyl bis (diphenylphosphinate), titanium tetrakis (diphenylphosphinate), and mixtures thereof.

8. The adhesive composition of claim 1, wherein the adhesive composition, after curing, exhibits a lap shear strength to aluminum of 2.3MPa or greater.

9. The adhesive composition of claim 1, wherein the adhesive composition after curing exhibits a V-0 rating at 6mm thickness in a UL 94 burn test.

10. The adhesive composition of claim 1, wherein the adhesive composition exhibits a thermal conductivity of 0.8W/(m-K) or greater according to astm e 1461 after curing.

11. The adhesive composition of claim 1, wherein the ethylenically unsaturated monomer is present in an amount of from 5 to 50 weight percent, preferably from 10 to 30 weight percent, based on the total weight of the adhesive composition.

12. The adhesive composition of claim 1, wherein the polymeric elastomer is present in an amount of from 1 to 40 weight percent, preferably from 2 to 20 weight percent, based on the total weight of the adhesive composition.

13. The adhesive composition of claim 1, wherein the initiator is present in an amount of 0.005 to 5 wt%, preferably 0.01 to 1 wt%, based on the total weight of the adhesive composition.

14. The adhesive composition of claim 1, wherein the vinyl terminated liquid rubber is present in an amount of from 0.1 to 10 weight percent, preferably from 1 to 5 weight percent, based on the total weight of the adhesive composition.

15. The adhesive composition of claim 1, wherein the thermally conductive filler is present in an amount of 20 to 90 weight percent, preferably 30 to 80 weight percent, based on the total weight of the adhesive composition.

16. The adhesive composition of claim 1, wherein the diorganophosphinate is present in an amount of 1 wt.% to 10 wt.%, preferably 2 wt.% to 8 wt.%, based on the total weight of the adhesive composition.

17. An adhesive composition comprising 5 to 50 weight percent ethylenically unsaturated monomer, 1 to 40 weight percent polymeric elastomer, 0.005 to 5 weight percent initiator, 0.1 to 10 weight percent vinyl terminated liquid rubber, 20 to 90 weight percent thermally conductive filler, 1 to 10 weight percent diorganophosphinate, wherein weight percent is based on the total weight of the adhesive composition.

18. A kit for providing a two-part reactive adhesive formulation, the kit comprising a part A chamber and a part B chamber, the part A chamber containing a part A composition, the part B chamber containing a part B composition capable of reacting with the part A composition, the part a composition and the part B composition can be combined in a preselected weight ratio to yield an adhesive composition, the adhesive composition includes 5 to 50 weight percent ethylenically unsaturated monomer, 1 to 40 weight percent polymeric elastomer, 0.005 to 5 weight percent initiator, 0.1 to 10 weight percent vinyl terminated liquid rubber, 20 to 90 weight percent thermally conductive filler, 1 to 10 weight percent diorganophosphinate, where weight percent is based on the total weight of the adhesive composition.

19. The kit of claim 18, wherein said part a compartment and said part B compartment are each selected from the group consisting of a drum, a barrel, and a pail.

Technical Field

The present invention relates generally to adhesive compositions, and more particularly to (meth) acrylic adhesive compositions for electrical devices having improved adhesive strength, thermal conductivity, and flame retardancy.

Background

Batteries such as primary batteries, secondary batteries, capacitors, and the like are widely used in the field of vehicle applications. In general, secondary batteries are rechargeable, especially on a large scale. Among them, lithium ion batteries are widely used as secondary batteries because they have excellent characteristics such as long life and large capacity. However, if the lithium ion battery is exposed to abnormal use environments, such as overcharge, short circuit, reverse connection, and heat, gas is generated within the battery due to an electrochemical reaction, thereby increasing the internal pressure of the battery. The battery swells due to increased internal pressure, and particularly if an abnormal use time such as overcharge is continued, the electrolyte or the active material is partially decomposed, resulting in rapid increase in internal pressure and temperature of the battery, which may cause risks of explosion and ignition.

Therefore, there is a need for an adhesive for battery pack fixation and insulation to have excellent thermal conductivity to transfer heat to a radiator or dissipate heat generated from a battery pack, and also to have an excellent flame retardant to reduce the risk of fire. Meanwhile, an adhesive for battery pack fixation in a vehicle is desired to have excellent adhesive strength to avoid adhesive failure at higher and lower temperatures and by external force such as shaking or vibration. In addition, there is a need for adhesives that are readily curable at room temperature without the aid of expensive heating or radiation equipment.

Accordingly, there remains a need to develop a flame retardant adhesive composition that overcomes the above problems and is suitable for use in vehicles, particularly for battery pack fixation.

Disclosure of Invention

The present invention relates to an adhesive composition that overcomes the above-mentioned drawbacks. The adhesive composition of the present invention has good lap shear strength after curing. The adhesive composition of the present invention exhibits excellent thermal conductivity after curing. The adhesive composition of the present invention has excellent flame retardancy after curing. Moreover, the application of the adhesive composition is simple and suitable for industrial production.

The present invention provides, in a broad aspect, an adhesive composition comprising:

a) an ethylenically unsaturated monomer, wherein the ethylenically unsaturated monomer,

b) an elastomer of a polymer, the elastomer being a polymer,

c) an initiator, wherein the initiator is selected from the group consisting of,

d) a liquid rubber terminated with a vinyl group,

e) a thermally conductive filler, and

f) a diorganophosphinate.

Also disclosed is an adhesive composition comprising 10 to 40 weight percent of an ethylenically unsaturated monomer, 2 to 40 weight percent of a polymeric elastomer, 0.005 to 5 weight percent of an initiator, 0.1 to 5 weight percent of a vinyl terminated liquid rubber, 20 to 90 weight percent of a thermally conductive filler, 1 to 10 weight percent of a diorganophosphinate salt, wherein weight percent is based on the total weight of the adhesive composition.

Also disclosed is a kit for providing a two-part reactive adhesive formulation comprising a part a compartment containing a part a composition and a part B compartment containing a part B composition reactive with the part a composition, the part a composition and the part B composition being combinable in a preselected weight ratio to yield an adhesive composition according to the invention.

Drawings

FIG. 1 is a schematic representation of a dual chamber applicator suitable for dispensing two-part reactive adhesives according to the present invention.

Detailed Description

The following paragraphs describe the present invention in detail. Each aspect described may be combined with one or more other aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

In the context of the present invention, the terms used are to be interpreted according to the following definitions, unless the context dictates otherwise.

As used herein, the singular forms "a", "an" and "the" include both the singular and the plural of the stated objects, unless the context clearly dictates otherwise.

As used herein, the terms "comprising" and "including" or "containing" are synonymous, inclusive or open-ended, and do not exclude additional unrecited elements, elements or method steps.

The recitation of numerical endpoints includes all numbers and fractions within the respective range, as well as the recited endpoints.

All references cited in this specification are hereby incorporated by reference in their entirety.

Unless defined otherwise, all terms, including technical and scientific terms, used in disclosing the invention, have the meaning conventionally understood by one of ordinary skill in the art to which this invention belongs. By way of further guidance, definitions of terms are included to better understand the teachings of the present invention.

According to the invention, the adhesive composition comprises:

a) an ethylenically unsaturated monomer, wherein the ethylenically unsaturated monomer,

b) an elastomer of a polymer, the elastomer being a polymer,

c) an initiator, wherein the initiator is selected from the group consisting of,

d) a liquid rubber terminated with a vinyl group,

e) a thermally conductive filler, and

f) a diorganophosphinate.

In one embodiment, the ethylenically unsaturated monomer is represented by formula (1):

wherein R is¹Is COOR²、CN、CHO、SO₃H、PO(OH)₂Or CONR³R⁴And R is²、R³And R⁴Independently of one another, hydrogen or C₁-C₁₈Alkyl, preferably C₁-C₁₂-alkyl, more preferably C₁-C₆-an alkyl group.

Examples of the ethylenically unsaturated monomer (preferably, a vinyl unsaturated monomer) include, but are not limited to, (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and stearyl (meth) acrylate, and (meth) acrylonitrile, (meth) acrolein, vinylsulfonic acid, vinylphosphonic acid, (meth) acrylamide, N-t-butylacrylamide and N-octylacrylamide. Two or more of the ethylenically unsaturated monomers may be used in combination.

Preferably, the ethylenically unsaturated monomer is selected from the group consisting of (meth) acrylates, N-t-butylacrylamide, (meth) acrylic acid, 2-ethylhexyl (meth) acrylate, and mixtures thereof.

In the present invention, the ethylenically unsaturated monomer is present in an amount of 5 to 50 wt%, preferably 10 to 30 wt%, based on the total weight of the adhesive composition.

According to the invention, the adhesive composition comprises a polymeric elastomer. The polymeric elastomer is preferably chlorosulfonated polyethylene or chlorinated polyethylene, more preferably nitrile rubber particles or powder, a wholly acrylic copolymer resin or wholly acrylic rubber particles, more preferably a methacrylate/acrylate monomer soluble polymeric elastomer, more preferably a core shell polymer or block copolymer rubber, most preferably polychloroprene, or a mixture of the foregoing.

The polychloroprene rubber is preferably a Neoprene rubber, such as Neoprene AD-5, AD-10, or WRT, available from DuPont Dow Elastomers. The block copolymer rubber is preferably a butadiene or isoprene and styrene block copolymer (e.g., SBS (styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butylene-styrene), and SB (styrene-butylene)), and is available from Shell Chemical Co as Kraton D-1155 and other Kraton class D elastomers, or Dexco as Vector 2411 IP. Other elastomers having a Tg less than about 25 ℃ that are soluble in ethylenically unsaturated monomers such as methacrylate/acrylate monomers may be used in place of polychloroprene and/or block copolymer rubber. Examples are homopolymers of epichlorohydrin and its copolymers with ethylene oxide, available as Hydrin from Zeon Chemicals, acrylate rubber pellets, available as HyTemp from Zeon, polyisoprene rubber, polybutadiene rubber, nitrile rubber and SBR rubber (random copolymers of butadiene and styrene).

The core-shell polymer is preferably a "core-shell" type graft copolymer. The core-shell polymers are preferably acrylonitrile-butadiene-styrene (ABS), methacrylate-butadiene-styrene (MBS) and methacrylate-acrylonitrile-butadiene-styrene (MABS). Blendex 338 is ABS powder available from GE Plastics. Less preferred alternatives to the core shell polymer are all acrylic copolymer resins such as the products nos. km330 and KM323B available from Rohm and Haas. A preferred nitrile rubber powder is available from Goodyear as Chemigum P-83. Optionally, all-acrylic rubber particles may be used, such as Sunigum available from Goodyear. Other resinous fillers known in the art that swell but are insoluble in the monomer solution may be used in place of the nitrile rubber powder to provide a paste-like consistency and further toughen the cured adhesive.

In the present invention, the polymeric elastomer is present in an amount of from 1 to 40 wt%, preferably from 2 to 20 wt%, based on the total weight of the adhesive composition.

The inhibitor is a free radical polymerization inhibitor that increases shelf life and prevents or inhibits premature polymerization, and is preferably selected from the group consisting of Hydroquinone (HQ), 4-Methoxyphenol (MEHQ), Butylated Hydroxytoluene (BHT), Phenothiazine (PTZ), and mixtures of the foregoing.

In the present invention, the initiator is present in an amount of 0.001 to 0.2 wt%, preferably 0.005 to 0.1 wt%, based on the total weight of the adhesive composition.

The initiator is a free radical initiator and is preferably a free radical initiator known in the art, more preferably a perester or a peracid, most preferably an organic peroxide or an organic hydroperoxide. Preferred initiators in the present invention are Benzoyl Peroxide (BPO), tert-butyl peroxybenzoate (TBPB), Cumene Hydroperoxide (CHP), tert-butyl hydroperoxide, dicumyl peroxide and tert-butyl peroxyacetate.

In the present invention, the initiator is present in an amount of 0.005 to 5 wt%, preferably 0.01 to 1 wt%, based on the total weight of the adhesive composition.

The vinyl terminated liquid rubber is preferably a vinyl terminated liquid rubber known in the art (e.g., liquid polybutadiene and/or liquid polyisoprene and copolymers thereof), more preferably polyether or polyester polyols and other oligomeric materials having vinyl functional end groups with a glass transition temperature below 0 ℃, more preferably methacrylate terminated or acrylate terminated polybutadiene-acrylonitrile copolymers such as Hycar VTBN, and most preferably methacrylate terminated or acrylate terminated polybutadiene such as Hycar VTB available from BF Goodrich.

In the present invention, the vinyl terminated liquid rubber is present in an amount of from 0.1 to 10 weight percent, preferably from 1 to 5 weight percent, based on the total weight of the adhesive composition.

According to the invention, the adhesive composition further comprises a thermally conductive filler to improve the dissipation of heat transferred to the cured adhesive. Examples of the thermally conductive filler are metal hydroxides, metal oxides, metals, and ceramics. Preferably, the thermally conductive filler may be aluminum hydroxide, magnesium hydroxide, aluminum oxide, silicon oxide, magnesium oxide, zinc oxide, titanium oxide, zirconium oxide, iron oxide, silicon carbide, boron nitride, aluminum nitride, titanium nitride, silicon nitride, titanium boride, carbon black, carbon fiber, carbon nanotube, diamond, nickel, copper, aluminum, titanium, gold, and silver. The crystalline form of the thermally conductive fillers may be any crystalline form of the chemical species, such as hexagonal or cubic crystals. The particle size of the filler is preferably about 10 μm or more and about 150 μm or less. When the particle size of the filler is adjusted to about 150 μm or less, the viscosity of the adhesive composition is suitable for application to a substrate. In order to improve the filling property, a thermally conductive filler surface-treated with silane or titanate may be used. The term "particle size" refers to the dimension of the longest length when measured as a straight line drawn through the center of gravity of the filler. The shape of the filler may be regular or irregular and includes, for example, polygons, cubes, ovals, spheres, needles, plates, flakes, or combinations thereof. The filler may be in the form of aggregated particles of a plurality of crystalline particles. Among these fillers, alumina and silica are particularly preferable because they are excellent in filling in the adhesive composition. Aluminum hydroxide is also preferred because it can impart flame retardancy to the cured adhesive and is also readily available as a raw material. Spherical alumina powders are commercially available from the BAK series sold by reflection Performance Materials co.

In the present invention, the thermally conductive filler is present in an amount of 20 to 90 wt%, preferably 30 to 80 wt%, based on the total weight of the adhesive composition.

The adhesive composition according to the invention also contains a diorganophosphinic salt to render the cured product of the composition flame retardant. The incorporation of the diorganophosphinate as a flame retardant filler is important to the present invention because when the adhesive composition is cured, flammability rating of UL 94V-0 may be achieved.

The term "diorganophosphinate" hereinafter includes diorganophosphinates not only by themselves, but also diorganophosphinates and polymers thereof.

In one embodiment, the diorganophosphinate is a diorgano monophosphonate represented by formula (2),

wherein

R¹And R²Identical or different and is H or a linear or branched C₁-C₆-alkyl, and/or aryl;

R³is straight-chain or branched C₁-C₁₀Alkylene radical, C₆-C₁₀-arylene, -alkylarylene or-arylalkylene;

m is Mg, Ca, Al, Sb, Sn, Ge, Ti, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K and/or a protonated nitrogen base;

m is 1 to 4;

n is 1 to 4; and

x is 1 to 4.

Particular preference is given to R¹And R²Identical or different and are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and/or phenyl.

Preferably R³Is methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene or n-dodecylene; phenylene or naphthylene; a methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene or tert-butylnaphthylene group; phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene.

M is preferably magnesium, calcium, aluminum or zinc, in particular aluminum or zinc.

The protonated nitrogen base is preferably a protonated form of ammonia or a protonated form of a primary, secondary, tertiary or quaternary amine.

Preferably m is 2 or 3; n is 1 or 3; and x is 1 or 2;

the diorganophosphinate salt of formula (2) is preferably selected from the group consisting of aluminum tris (diethylphosphinate), aluminum tris (methylethylphosphinate), aluminum tris (diphenylphosphinate), zinc bis (diethylphosphinate), zinc bis (methylethylphosphinate), zinc bis (diphenylphosphinate), titanyl bis (diethylphosphinate), titanium tetrakis (diethylphosphinate), titanyl bis (methylethylphosphinate), titanium tetrakis (methylethylphosphinate), titanyl bis (diphenylphosphinate), titanium tetrakis (diphenylphosphinate), and any desired mixtures thereof. The diorganophosphinate salt is available from Clariant Chemicals under the trade name Exolit OP series.

In the present invention, the diorganophosphinate is present in an amount of 1 to 10 weight percent, preferably 2 to 8 weight percent, based on the total weight of the adhesive composition.

The inventors have surprisingly found that the diorganophosphinic salts are particularly suitable for reducing the flammability of (meth) acrylate-based adhesives over other phosphorus-containing flame retardants commonly used in the art, such as phosphazenes and ammonium polyphosphates.

In one embodiment, the adhesive composition comprises less than 6%, preferably is substantially free, more preferably free, of phosphazenes (e.g., cyclic phosphazene oligomers).

In another embodiment, the adhesive composition comprises less than 6%, preferably is substantially free, more preferably free, of ammonium polyphosphates.

In accordance with the present invention, the adhesive composition may optionally include a flame retardant synergist so long as the composition, when cured, can achieve a V-0 rating of UL 94. Mention may be made, for example, of melamine phosphate, dimelamine phosphate, pentamelamine triphosphate, dimelamine diphosphate, tetrammine triphosphate, hexamelamine pentaphosphate, melamine diphosphate, melamine tetraphosphate, melamine pyrophosphate, melamine polyphosphate, melam polyphosphates, melem polyphosphates and/or melon polyphosphates, or mixtures of these substances.

The composition may also optionally include a catalyst for promoting the reaction of the ethylenically unsaturated monomer and the initiator. Traditionally, the compositions incorporate catalysts such as tertiary amines, substituted phosphines, salts of quaternary organophosphonium compounds, guanidines, imidazoles, and the like. Representative tertiary amines include N, N-diisopropyl-p-chloroaniline, N-diisopropyl-p-bromoaniline, N-diisopropyl-p-bromo-m-methylaniline, N-dimethyl-p-chloroaniline, N-dimethyl-p-bromoaniline, N-diethyl-p-chloroaniline, N-diethyl-p-bromoaniline, N-dimethyl-p-aniline, N-dimethyl-p-toluidine (DMPT); n, N-diethyl-p-toluidine, N-diisopropyl-p-toluidine, dihydroxyethyl-p-toluidine (DHEPT), bis (hydroxyethyl) -p-toluidine. Examples of guanidines include dicyandiamide, methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, and tolylguanidine. Examples of substituted phosphines include tris (2, 6-dimethoxyphenyl) phosphine, tris (p-tolyl) -phosphine, triphenylphosphine and triphenylphosphine. Examples of the imidazole include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole and 2-ethyl-4-methylimidazole. Salts of quaternary organophosphonium compounds that may be used include, but are not limited to, organophosphonium functional acetate compounds such as ethyl triphenyl phosphonium acid acetate complex available from Rohm and Haas.

The adhesive composition may optionally include an adhesion promoter to enhance the adhesion between the adhesive and the metal substrate. The adhesion promoters useful in the present invention are known phosphorus-containing compounds which exist as monoesters of phosphinic acids having one vinyl or allyl unsaturated unit, monoesters and diesters of phosphinic acids and phosphoric acid. Ethylenic unsaturation is preferred. Representative of the phosphorus-containing adhesion promoter are, but not limited to, phosphoric acid; 2-methacryloyloxyethyl phosphate; bis- (2-methacryloyloxyethyl) phosphate; 2-acryloyloxyethyl phosphate; bis- (2-acryloyloxyethyl) phosphate; methyl- (2-methacryloyloxyethyl) phosphate; ethyl methacryloyloxyethyl phosphate; methacryloyloxyethyl phosphate; ethyl acryloyloxyethyl phosphate; propylacryloyloxyethyl phosphate, isobutylacryloyloxyethyl phosphate, ethylhexyl acryloyloxyethyl phosphate, halopropylacryloyloxyethyl phosphate, haloisobutylacryloyloxyethyl phosphate or haloethylhexyl acryloyloxyethyl phosphate; vinyl phosphonic acid; cyclohexene-3-phosphonic acid; (alpha-hydroxybutene-2-phosphonic acid; 1-hydroxy-1-phenylmethane-1, 1-diphosphonic acid; 1-hydroxy-1-methyl-1-diphosphonic acid; 1-amino-1-phenyl-1, 1-diphosphonic acid; 3-amino-3-hydroxypropane-1, 1-diphosphonic acid; amino-tris (methylenephosphonic acid); gamma-amino-propylphosphonic acid; gamma-glycidoxypropylphosphonic acid; phosphoric acid-mono-2-aminoethyl ester; allylphosphonic acid; allylphosphinic acid; beta-methacryloyloxyethyl phosphinic acid; diallyl phosphinic acid; beta-methacryloyloxyethyl) phosphinic acid and allyl methacryloyloxyethyl phosphinic acid. Such as those sold by Rhodia under the trade names Sipomer PAM-100 and PAM 200, by Kyoeisha Chemicals Company under the trade names Light Ester PM-1 and PM-2, and by Sartomer under the trade names Sartomer CD 9052 or CD 9053. A preferred adhesion promoter is methacryloyloxyethyl phosphate.

Other adhesion promoters useful in the present invention are the known alkenyl-functional silanes having an unsaturated organic moiety bonded to a silicon atom, such as an unsaturated acrylic, vinyl, allyl, methallyl, propenyl, hexenyl, ethynyl, butadienyl, hexadienyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, vinylcyclohexylethyl, divinylcyclohexylethyl, norbornenyl, vinylphenyl or styryl group. Other alkenyl functional organometallics include titanates such as vinyl alkyl titanates, zirconates, zinc diacrylate and zinc dimethacrylate.

Waxes may be used in the flame retardant adhesive composition to increase open time, and are preferably a honey Wax or a chlorinated Wax or other Wax, more preferably Wax 58 available from IG International. Polymeric resins, such as polyamide powders, for example Disparlon 6200 available from King Industries, which act as thixotropic and/or toughening agents may be added. Antioxidants such as BHT may also be used. Other optional ingredients include scavengers or chelating agents such as EDTA, pigments, dyes, reinforcing fibers, and the like.

Suitable plasticizers optionally added to the adhesive composition may be high boiling temperature solvents or softeners. Examples of suitable plasticizers are esters made from anhydrides or acids and suitable alcohols having from about 6 carbon atoms to about 13 carbon atoms. Other suitable plasticizers include adipates, phosphates, benzoates or phthalates, polyalkylene oxides, sulfonamides, and the like. The plasticizer includes dioctyl adipate plasticizer (DOA), triethylene glycol di-2-ethylhexanoate plasticizer (TEG-EH), trioctyl trimellitate plasticizer (TOTM), triacetin (triacetin plasticizer), 2, 4-trimethyl-1, 3-pentanediol diisobutyrate plasticizer (TXIB), diethyl phthalate plasticizer (DEP), dioctyl terephthalate plasticizer (DOTP), dimethyl phthalate plasticizer (DMP), dioctyl phthalate plasticizer (DOP), dibutyl phthalate plasticizer (DBP), ethylene oxide, toluene sulfonamide, and dipropylene glycol benzoate. Other commercially available plasticizers may also be used. Useful stabilizers provide free radical trapping activity and are generally selected with reference to at least some of the following considerations: compatibility with the resin system, temperature stability of the stabilizer at processing temperatures, whether the stabilizer will produce undesirable coloration, and whether the stabilizer will not interact with other additives.

Also disclosed is an adhesive composition comprising 10 to 40 weight percent of an ethylenically unsaturated monomer, 2 to 40 weight percent of a polymeric elastomer, 0.02 to 10 weight percent of an initiator, 0.1 to 5 weight percent of a vinyl terminated liquid rubber, 20 to 90 weight percent of a thermally conductive filler, 1 to 10 weight percent of a diorganophosphinate salt, wherein weight percent is based on the total weight of the adhesive composition.

As is known in the art, the adhesive composition of the present invention is a two-part reactive adhesive prepared in part a and part B, which are kept separate in the part a and part B chambers. The chamber may be, for example, a compartment or a separate container or cartridge (bars) or pail (pails). Part a and part B are mixed at the time of use, at which time they react and form the final adhesive. As is known in the art, there is a wide range for which ingredients are placed in part a and which ingredients are placed in part B. An important requirement is that the components that initiate the reaction remain separate or apart from the material with which they will react. This can be seen in the examples below. Typical divisions into parts a and B are known in the art and are shown in the examples herein. Typically, 50 parts by weight of part a is mixed with 50 parts by weight of part B. Alternatively, the ratio of a to B may be about 5:1, 3:1, 2:1, 1:2, 1:3, or 1:5 or other ratios.

Referring to fig. 1, there is shown an applicator or kit 10 having a cartridge 12, the cartridge 12 having a nozzle 24. The cartridge 12 comprises two separate chambers or compartments, a first chamber 14 containing part a of an adhesive composition according to the invention and a second chamber 16 containing the corresponding part B of an adhesive composition according to the invention. The applicator 10 also has a pair of pistons 18 and 20 connected by a double piston handle 22. When the handle 22 is pushed down, parts a and B are expelled from their respective chambers and combine and mix together as they exit the nozzle 24. They are then preferably further mixed together so that they can react sufficiently to form the final adhesive. Alternatively, a kit may be provided that includes a 55 gallon drum (drum) or barrel or chamber of part a and a 55 gallon pail or chamber of part B mixed in an a: B ratio of 1: 1.

The present invention also provides a kit for providing a two-part reactive adhesive formulation, the kit comprising a part a chamber and a part B chamber, the part A chamber containing a part A composition, the part B chamber containing a part B composition reactive with the part A composition, the part a composition and the part B composition can be combined in a preselected weight ratio to produce an adhesive composition, the adhesive composition includes 10 to 40 weight percent of an ethylenically unsaturated monomer, 2 to 40 weight percent of a polymeric elastomer, 0.02 to 10 weight percent of an initiator, 0.1 to 5 weight percent of a vinyl terminated liquid rubber, 20 to 90 weight percent of a thermally conductive filler, 1 to 10 weight percent of a diorganophosphinate, wherein weight percent is based on the total weight of the adhesive composition.

The adhesives of the invention are preferably used to bond metal, composite and/or plastic parts without or with minimal surface treatment, preferably in the transportation, automotive and general industrial markets. The adhesive is preferably used where high tensile strength, peel strength, flame retardancy, thermal conductivity, and durability are required. The combination of vinyl terminated liquid rubber, polymeric elastomer, thermally conductive filler and flame retardant in the adhesives of the invention is believed to provide enhanced performance in terms of flame retardancy, heat dissipation effectiveness, and toughness and low temperature impact.

The adhesive composition, after curing, exhibits a lap shear strength to aluminum of 2.3Mpa or greater.

The adhesive composition after curing exhibits a V-0 rating at a thickness of 6mm in the UL 94 burn test.

The adhesive composition of the invention is preferably in liquid form at 25 ℃. The brookfield viscosity of the composition is preferably from 50cPs to 1,000,000cPs at 25 ℃.

The adhesive composition, after curing, exhibits a thermal conductivity of 0.8W/(m-K) or higher according to ASTM E1461.

The following examples are intended to assist those skilled in the art in better understanding and practicing the present invention. The scope of the present invention is not limited by the embodiments but is defined by the appended claims. All parts and percentages are by weight unless otherwise indicated.

Examples

The following materials were used in the examples. MMA was methyl methacrylate, purchased from Evonik. MAA is methacrylic acid, available from Sinopharm. EHMA is ethylhexyl methacrylate, available from Evonik. Kraton D-1155 is a polymeric elastomer available from Kraton. H-VTB is a vinyl terminated liquid rubber available from CRAY VALLEY. TPP is triphenylphosphine from Sinopharm. P1-M is an adhesion promoter available from Kyeisha. DMPT is N, N-dimethyl-p-toluidine from Sinopharm. Wax 58 is a Wax from Sinopharm. BAK-5 is a spherical alumina powder available from Bestry. SJR-20 is a silica filler available from Estone. Exolit OP 935 is tris (diethylidene) available from Clariant ChemicalsPhosphonic acid) aluminum salt. Exolit AP422, available from Clariant Chemicals, is of the formula (NH)₄PO₃)_nWherein n is 20-1000, especially 200-1000, which is slightly soluble in water. Exolit AP750, available from Clariant Chemicals, is a halogen-free flame retardant mixture comprising polymeric ammonium polyphosphate in combination with an aromatic carboxylic acid ester of tris (2-hydroxyethyl) isocyanurate as a synergist. BHT is 2, 6-di-tert-butyl-p-cresol from Sinopharm and BPO is benzoyl peroxide from Sinopharm. EPON 828 is a diglycidyl ether of bisphenol A, available from Hexion Specialty Chemicals GmbH. Kraton G1652 is an SEBS copolymer available from Kraton. DINA is diisononyl adipate available from Wengiang Chemical. Ultramarine blue colorants were purchased from Tianlan.

Two-part adhesive compositions were prepared as examples and comparative examples. Part a of the composition was formulated as follows according to the components and amounts in table 1: all components except the thermally conductive filler were thoroughly mixed by Speed mixer DAC 400 (available from FlackTek Inc.) until the mixture was completely dissolved, and then the thermally conductive filler was added to the mixture and thoroughly mixed to obtain part a. Part B of the composition contained 4G of BPO, 2.34G of Epon 828, 1.3G of Kraton G1652, 2.33G of DINA and 0.03G of ultramarine blue colorant. All components of part B were thoroughly mixed using a three roll mill to obtain a homogeneous part B. Parts a and B are mixed together when applied to a substrate.

TABLE 1 formulation of part A of the adhesive composition (in grams)

Evaluation of Performance

Double lap joints were formed between substrates of Al (aluminum) and Al, Al and PET (polyethylene terephthalate). All these substrates had a thickness of 127 μm and the overlap of the lap shear modules was 25.4mm by 12.5 mm. The substrates were coated with the adhesive composition and tested for adhesive strength, thermal conductivity, flame retardancy according to the following methods.

Adhesive strength

The adhesive strength of each cured adhesive was measured by an Instron 5669 tester. The Al-Al, Al-PET assembly with applied adhesive composition was cured at room temperature for 24 hours and tested according to ASTM 1002.

Thermal conductivity

The thermal conductivity of the cured adhesive was measured according to ASTM E1461. The thickness of the test piece was 1.6mm and the diameter was 12.7 mm.

Flame retardancy

The flame retardancy of the cured adhesive was measured according to UL 94 standards. The cured samples were cut to have dimensions of 127mm by 12.7mm by 6 mm. If the classification is determined to be V-0, it is evaluated as "PASS" (PASS). If the classification is determined to be V-1 or higher, it is evaluated as "Fail" (Fail).

The test results are shown in tables 2 to 4. It is evident that all examples of the present invention exhibit excellent adhesive strength, thermal conductivity and flame retardancy and are therefore suitable for use in vehicle battery adhesion and insulation. The comparative examples did not achieve a V-0 rating in the UL 94 test due to the absence of flame retardants, conventional flame retardants, or the absence of inorganic fillers, which resulted in higher loadings of organic components.

TABLE 2 test results of adhesive Strength (MPa)

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7
								Al-Al	15.4	14.61	9.43	2.49	1.98	12.63	12.52
Al-PET	4.5	-	4.6	1.76	1.34	6.46	5.43
									Example 8	Example 9	Example 10	Example 11	Example 12	Comparative example 1	Comparative example 2
Al-Al	9.12	14	8.63	14	9.12	13.32	16.81
								Al-PET	4.18	5.9	4.85	8.46	4.18	6.23	6.41

TABLE 3 thermal conductivity test results (W/m. K)

Example 1	Example 8	Example 9	Example 10	Example 12	Comparative example 5	Comparative example 6
							0.982	1.2	1.0	1.45	1.2	1.0	1.0

TABLE 4 flame retardancy test results (UL 94)

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Example 8

Example 9

Qualified

Qualified

Qualified

Qualified

Qualified

Qualified

Qualified

Qualified

Qualified

Example 10

Example 11

Example 12

Comparative example 1

Comparative example 2

Comparative example 3

Comparative example 4

Comparative example 5

Comparative example 6

Qualified

Qualified

Qualified

Fail to be qualified

Fail to be qualified

Fail to be qualified

Fail to be qualified

Fail to be qualified

Fail to be qualified