Two-component polyurethane adhesive composition

Abstract

The two-part thermally conductive polyurethane adhesive comprises component A and component B. Component A is an NCO-terminated prepolymer made by reacting at least one polyol having an Mn greater than 2,000 Da and an OH functionality of 2-3 with 30-45 wt. %, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-MDI and 4,4'-MDI. Component B comprises at least one polyol having an Mn less than 1,000 Da and an OH functionality of at least 2. The bonded assembly comprises a first substrate and a second substrate bonded to the first substrate by the polyurethane adhesive made by mixing components A and B.

Description

[Technical field]

[0001] The present invention relates to the field of two-part polyurethane adhesive compositions. [Background technology]

[0002] Two-part polyurethane adhesives offer a versatile bonding means and their use is increasing in the automotive industry due in part to the desire to reduce weight caused by traditional attachment means such as rivets.

[0003] Two-part polyurethanes include an isocyanate component and a polyol component. The isocyanate component includes at least one isocyanate-terminated molecule, and the polyol component includes at least one polyol. When the two components are mixed immediately before use, the OH groups of the polyol react with the NCO groups of the isocyanate-terminated molecule to form a high molecular weight polyurethane that can be linear or branched (i.e. crosslinked). As the components are mixed and the molecular weight begins to increase, the viscosity of the mixture also increases. There is a limited time for the adhesive mixture to have a viscosity that allows it and the parts that are to be bonded using it to be manipulated. The time from mixing to a given degree of cure (and / or viscosity) is called the "working time". In some applications, a longer working time is desired. Summary of the Invention [Means for solving the problem]

[0004] In a first aspect, the present invention provides a two-part thermally conductive polyurethane adhesive, the adhesive comprising: (A) Component A: (ai) Molecular weight (M n) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally, a catalyst capable of catalyzing the reaction of OH groups with NCO groups.

[0005] In a second aspect, the present invention provides a kit for producing a thermally conductive polyurethane adhesive, the kit comprising: (A) Component A: (ai) Molecular weight (M n ) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally, a catalyst capable of catalyzing the reaction of OH groups with NCO groups.

[0006] In a third aspect, the present invention provides a method for adhering two or more substrates, the method comprising: (1) (A) Component A: (ai) Molecular weight (M n) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally providing an adhesive comprising a catalyst capable of catalyzing the reaction of OH groups with NCO groups; (2) mixing component A with component B to form an adhesive mixture; (3) applying the adhesive mixture to a first substrate; (4) bringing the first substrate into adhesive contact with a second substrate; (5) curing the adhesive mixture.

[0007] In a fourth aspect, the present invention provides a bonded assembly, the assembly comprising: (1) a first substrate; (2) a second substrate adhered to the first substrate; The first substrate and the second substrate are (A) Component A: (ai) Molecular weight (M n ) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally, are bonded together by an adhesive made by mixing with a catalyst capable of catalyzing the reaction of OH groups with NCO groups. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present inventors have determined that the molecular weight (M n ) of at least one polyol having an OH functionality of 2 to 3 and a molecular weight (M) of more than 2,000 Da is reacted with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; n It has been discovered that it is possible to achieve longer pot life and slower viscosity development in polyurethane adhesives by using an isocyanate component (component A) comprising a prepolymer made by using a polyol component comprising at least one polyol having an OH functionality of at least 2 and an isocyanate component (component B) having an isocyanate group of less than 1,000 Da.

[0009] Definitions and Abbreviations MDI: Methylene-bis-(phenylisocyanate) HDI: Hexamethylene diisocyanate IPDI: Isophorone diisocyanate PU: Polyurethane GPC: Gel Permeation Chromatography RH: Relative humidity

[0010] The equivalent weight and molecular weight were determined by gel permeation chromatography (GPC) using a Malvern Viscothek GPC max instrument, tetrahydrofuran (THF) was used as the eluent, PL GEL MIXED D (Agilent, 300×7.5 mm, 5 μm) was used as the column, and MALVERN Viscothek TDA (integrated refractive index viscometer and light scattering) was used as the detector.

[0011] Component A (Isocyanate) Component A has a molecular weight (M n ) greater than 2,000 Da and at least one polyol having an OH functionality of 2 to 3 with 30 to 45 weight percent, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI.

[0012] The polyol is preferably a polyether polyol, in particular poly(C 2~4 alkylene oxide) polyols.

[0013] In a preferred embodiment, the polyol is selected from poly(propylene oxide) polyols.

[0014] The polyol used to prepare the prepolymer preferably has a functionality of 2.5 to 3, more preferably 3.

[0015] In a preferred embodiment, the polyol used to prepare the prepolymer is a polyether polyol having a functionality of 2.5 to 3, more preferably 3.

[0016] In a more preferred embodiment, the polyol used to prepare the prepolymer is a poly(C 2~4 alkylene oxide polyol.

[0017] In another preferred embodiment, the polyol used to prepare the prepolymer is a poly(propylene oxide) polyol having a functionality of 2.5 to 3, more preferably 3.

[0018] In another preferred embodiment, the polyol used to prepare the prepolymer has a molecular weight (M n), more preferably it has a molecular weight (M n ).

[0019] In a preferred embodiment, the polyol used to prepare the prepolymer has a molecular weight (M n ), in particular poly(C 2~4 More preferably, it is selected from polyols having a molecular weight (M n ).

[0020] In a preferred embodiment, the polyol has a molecular weight (M n ), more preferably it is selected from poly(propylene oxide) polyols having a molecular weight (M) of 3,000 Da. n ).

[0021] The polyol used to prepare the prepolymer preferably has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ), more preferably it has a molecular weight (M n ).

[0022] In a preferred embodiment, the polyol used to prepare the prepolymer has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ), more preferably it is a polyether polyol having a molecular weight (M n ).

[0023] In a more preferred embodiment, the polyol used to prepare the prepolymer has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ) having poly(C 2~4 More preferably, it is a polyol having a molecular weight (M) of 3,000 Da. n ).

[0024] In another preferred embodiment, the polyol used to prepare the prepolymer has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ), more preferably it is a poly(propylene oxide) polyol having a molecular weight (M) of 3,000 Da. n ).

[0025] The prepolymer may be made with a mixture of polyols selected from those described herein.

[0026] The polyisocyanate is selected from aliphatic polyisocyanates and mixtures of 2,4'-MDI and 4,4'-MDI.

[0027] In a preferred embodiment, the polyisocyanate is aliphatic, with isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), and hexamethylene diisocyanate (HDI), and mixtures thereof being especially preferred.

[0028] In another preferred embodiment, the polyisocyanate is a mixture of 2,4'-MDI and 4,4'-MDI. More preferably, the weight ratio of 2,4'-MDI to 4,4'-MDI is 0.667 to 1.5, more preferably 0.8 to 1.5, and even more preferably 1 to 1.5.

[0029] Particularly preferred are mixtures of 2,4'-MDI and 4,4-MDI in a 1:1 weight ratio of 2,4'-MDI to 4,4-MDI.

[0030] The NCO-terminated prepolymers of component A are prepared by reacting at least one polyol with at least one polyisocyanate. The reaction is preferably carried out under dry and inert conditions, in particular under vacuum. In a preferred embodiment, the at least one polyol is first dried under vacuum and at elevated temperature (>100° C.), then cooled (e.g. to 80° C.), after which the at least one polyisocyanate is added under vacuum. The mixture is reacted under vacuum for 1-2 hours. The prepolymer may be purified, but preferably the resulting reaction mixture is used without purification.

[0031] The at least one polyisocyanate is used in such an amount that there is an excess of NCO groups relative to the OH groups of the polyol. In a preferred embodiment, the at least one polyisocyanate is used in a stoichiometric excess of 2 to 15 times the polyol, more preferably 8 to 12 times the polyol, and particularly preferably 10 times the polyol.

[0032] In a preferred embodiment, the prepolymer is made by reacting a polyether polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0033] In another preferred embodiment, the prepolymer is poly(C 2~4 It is produced by reacting an alkylene oxide polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0034] In another preferred embodiment, the prepolymer is made by reacting a poly(propylene oxide) polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0035] In another preferred embodiment, the prepolymer is prepared by reacting a polyether polyol having a functionality of 2.5 to 3, more preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0036] In another preferred embodiment, the prepolymer is a poly(C 2~4 It is produced by reacting an alkylene oxide polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0037] In another preferred embodiment, the prepolymer is made by reacting a poly(propylene oxide) polyol having a functionality of 2.5 to 3, more preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0038] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ) with a mixture of 2,4'-MDI and 4,4'-MDI.

[0039] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ) having poly(C 2~4 It is made by reacting an alkylene oxide polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0040] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ) with a mixture of 2,4'-MDI and 4,4'-MDI.

[0041] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n) and a polyether polyol having a functionality of 2.5 to 3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0042] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ) and a polyether polyol having a functionality of 2.5 to 3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0043] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ), and poly(C 2~4 It is made by reacting an alkylene oxide polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0044] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ), and a poly(propylene oxide) polyol having a functionality of 2.5 to 3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0045] In another preferred embodiment, the prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ) and a polyether polyol having a functionality of 2.5 to 3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0046] In a particularly preferred embodiment, the prepolymer is prepared by reacting a poly(propylene oxide) polyol of molecular weight (Mn) 3,000 Da and functionality 3 with a 1:1 (wt:wt) mixture of 2,4'-MDI and 4,4'-MDI.

[0047] The at least one polyol is preferably used in component A in an amount of 10 to 40% by weight, more preferably 25 to 35% by weight, particularly preferably 28 to 29% by weight, based on the total weight of component A. It should be understood that the polyol is in prepolymer form.

[0048] The at least one polyisocyanate is used in component A in an amount of 20 to 50% by weight, based on the total weight of component A, more preferably 30 to 40% by weight, more particularly preferably 34 to 36% by weight.

[0049] The NCO-terminated prepolymer preferably contains 40 to 50% by weight, more preferably 42 to 48% by weight, and particularly preferably 43 to 45% by weight, of polyol, based on the total weight of the prepolymer.

[0050] The NCO-terminated prepolymer preferably contains 50 to 60% by weight, more preferably 52 to 58% by weight, and particularly preferably 54 to 56% by weight of diisocyanate, based on the total weight of the prepolymer.

[0051] The prepolymers are preferably used without purification. The prepolymer mixture is preferably used in component A in an amount of 50 to 75% by weight, more preferably 55 to 70% by weight, and more particularly preferably 60 to 66% by weight, based on the total weight of component A.

[0052] Component A may additionally comprise talc. If used, the talc is preferably present in an amount of 25 to 40% by weight, more preferably 30 to 40% by weight, and especially preferably 32 to 37% by weight, based on the total weight of component A.

[0053] Component A may additionally comprise fumed silica. If used, the fumed silica is preferably present at 0.75 to 2 weight percent, more preferably 1 to 2 weight percent, based on the total weight of Component A.

[0054] Component A is typically formulated by drying solid raw materials such as talc and fumed silica at elevated temperatures under vacuum. Preferably, drying is carried out until the moisture content is 300 ppm or less. After adding the prepolymer to the dry raw materials and mixing under reduced pressure until homogeneous, Component A is stored in a moisture-proof container.

[0055] Component B (Polyol) Component B has a molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, and (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.

[0056] The at least one polyol preferably comprises a polyol having a molecular weight (Mn) of more than 400 Da. The at least one polyol preferably comprises a polyol having a molecular weight (Mn) of 400 to 1,000 Da, more preferably 500 to 1,000 Da.

[0057] In a preferred embodiment, the at least one polyol comprises a polyol having a functionality of 3 or greater.

[0058] In a more preferred embodiment, the at least one polyol comprises a polyol having a functionality of 3 or greater and a molecular weight (Mn) of 400 to 1,000 Da, more preferably 500 to 1,000 Da.

[0059] In a more preferred embodiment, the at least one polyol comprises a mixed polyol, particularly a mixture of a polyol having a functionality of three and a polyol having a functionality greater than three.

[0060] In a preferred embodiment, the at least one polyol comprises a polyether polyol. A preferred polyether polyol is poly(C 2~4 In a particularly preferred embodiment, the polyether polyol is selected from poly(alkylene oxide)-based polyols, in particular poly(ethylene oxide)-, poly(propylene oxide)-, and poly(butylene oxide)-based polyols, and mixtures thereof. In a particularly preferred embodiment, the polyether polyol is selected from poly(propylene oxide)-based polyols.

[0061] In another preferred embodiment, the at least one polyol comprises a triol. The triol can be, for example, poly(C 2~4 In a particularly preferred embodiment, the triol is castor oil.

[0062] In a preferred embodiment, the at least one polyol comprises a mixture of a polyether polyol and castor oil, in particular a mixture of a polyether polyol having a functionality of more than 3, more preferably more than 4, particularly preferably more than 5, and castor oil.

[0063] In a preferred embodiment, the polyether polyol having a functionality greater than 3, more preferably greater than 4, particularly preferably greater than 5, is a poly(propylene oxide) polyol.

[0064] In a preferred embodiment, Component B comprises 40 to 60 wt. % of a triol, based on the total weight of Component B.

[0065] In a preferred embodiment, component B comprises 0-10 wt. % of a polyol having a functionality greater than 3, more preferably greater than 4.

[0066] In a preferred embodiment, component B comprises 0-20% by weight of a polyol having a functionality greater than 2, more preferably a functionality of 3, and a molecular weight less than 500 Da, more preferably less than 400 Da.

[0067] In another preferred embodiment, component B comprises 40-60 wt. % of a triol, based on the total weight of component B, 0-10 wt. % of a polyol having a functionality greater than 3, more preferably greater than 4, and 0-20 wt. % of a polyol having a functionality greater than 2, more preferably a functionality of 3, and a molecular weight less than 500 Da, more preferably less than 400 Da.

[0068] In another preferred embodiment, the at least one polyol comprises a mixture of 80 to 97% by weight, more preferably 85 to 95% by weight, particularly preferably 91 to 94% by weight of castor oil and 3 to 20% by weight, more preferably 5 to 15% by weight, particularly preferably 6 to 9% by weight of a polyether polyol, in particular a polyether polyol having a functionality of more than 3, more preferably more than 4, particularly preferably more than 5 (wherein the weight % is based on the total weight of polyols in component B).

[0069] In another preferred embodiment, the at least one polyol comprises a mixture of 80 to 97% by weight, more preferably 85 to 95% by weight, particularly preferably 91 to 94% by weight of a triol and 3 to 20% by weight, more preferably 5 to 15% by weight, particularly preferably 6 to 9% by weight of a polyether polyol having a functionality of more than 3, more preferably more than 4, particularly preferably more than 5, based on the total weight of polyols in component B.

[0070] In a particularly preferred embodiment, the at least one polyol comprises a mixture of poly(propylene oxide) having a functionality of 6 and castor oil.

[0071] In another particularly preferred embodiment, the at least one polyol comprises a mixture of 80 to 97% by weight, more preferably 85 to 95% by weight, particularly preferably 91 to 94% by weight of castor oil and 3 to 20% by weight, more preferably 5 to 15% by weight, particularly preferably 6 to 9% by weight of a poly(propylene oxide) polyol having a functionality of 6 (wherein the weight percentages are based on the total weight of polyols in component B).

[0072] Component B additionally optionally comprises a catalyst capable of catalyzing the reaction of isocyanate groups with OH groups.

[0073] Examples of such catalysts include tertiary amine catalysts, organometallic catalysts such as bismuth catalysts, alkyltin carboxylates, oxides and tin mercaptides.

[0074] Specific examples of tertiary amine catalysts include N-methylmorpholine, N-methylimidazole, triethylenediamine, bis-(2-dimethylaminoethyl)-ether, 1,4-diazabicyclo[2.2.2]octane (DABCO), dimethylcyclohexylamine, dimethylethanolamine, 2,2-dimorpholinyl diethyl ether (DMDEE), N,N,N-dimethylaminopropylhexahydrotriazine, dimethyltetrahydropyrimidine, tetramethylethylenediamine, dimethylcyclohexylamine, 2,2-N,N-benzyldimethylamine, Examples of the diamine include dimethylethanolamine, dimethylaminopropylamine, pentadimethyldiethylenetriamine, N,N,N',N'-tetramethyl-1,6-hexanediamine, N,N',N'-trimethylaminoethylpiperazine, 1,1'-[[3-(dimethylamino)propyl]imino]bispropan-2-ol, 1,3,5-tris[3-(dimethylamino)propyl]hexahydro-1,3,5-triazine, N-N-dimethyldipropylenetriamine, and N,N,N'-trimethylaminoethylethanolamine, with DMDEE being particularly preferred.

[0075] When an organometallic catalyst is used, it is any organometallic catalyst capable of catalyzing the reaction between an isocyanate and a functional group having at least one reactive hydrogen. Examples include bismuth catalysts, metal carboxylates, such as tin carboxylates, zinc carboxylates, etc. Metal alkanoates include stannous octoate, bismuth octoate, or bismuth neodecanoate. Preferably, the at least one organometallic catalyst is a bismuth catalyst or an organotin catalyst. Examples include dibutyltin dilaurate, dimethyltin dineodecanoate, dimethyltin mercaptide, dimethyltin carboxylate, dimethyltin dioleate, dimethyltin dithioglycolate, dibutyltin mercaptide, dibutyltin bis(2-ethylhexylthioglycolate), dibutyltin sulfide, dioctyltin dithioglycolate, dioctyltin mercaptide, dioctyltin dioctoate, dioctyltin dineodecanoate, dioctyltin dilaurate. In a preferred embodiment, the catalyst is a tin catalyst, particularly preferably dioctyltin mercaptide and / or dimethyltin dithioglycolate. In a particularly preferred embodiment, the catalyst is dioctyltin mercaptide.

[0076] The catalyst is preferably used in an amount of 0.0005 to 0.002% by weight, more preferably 0.00075 to 0.0015% by weight, based on the total weight of component B.

[0077] In a preferred embodiment, the catalyst is dioctyltin mercaptide, which is used at 0.0005 to 0.002% by weight, more preferably 0.00075 to 0.0015% by weight, based on the total weight of component B.

[0078] Component B may additionally comprise talc. If used, the talc is preferably present in an amount of 20 to 50% by weight, more preferably 30 to 40% by weight, and especially preferably 30 to 34% by weight, based on the total weight of component B.

[0079] Component B may additionally comprise fumed silica. If used, the fumed silica is preferably present at 0.75 to 2 weight percent, more preferably 1 to 2 weight percent, based on the total weight of Component A.

[0080] Component B may additionally contain a water scavenger such as a molecular sieve. If used, the molecular sieve is preferably used at 1 to 5 wt. %, more preferably 2 to 4 wt. %, based on the total weight of Component B.

[0081] Component B is typically formulated by drying solid raw materials such as talc and fumed silica at elevated temperatures under vacuum. Preferably, drying is carried out until the moisture content is 300 ppm or less. At least one polyol and catalyst are added to the dry raw materials and mixed under reduced pressure until homogeneous, after which Component B is stored in a moisture-proof container.

[0082] Manufacturing method The adhesive composition of the present invention is manufactured by mixing the ingredients of each component separately, preferably under inert and dry conditions and / or under vacuum, until a homogenous mixture is obtained. Once the components are prepared, they are stored in separate containers until use.

[0083] How to use In one aspect, the present invention provides a method for bonding two or more substrates, the method comprising: (1) (A) Component A: (ai) Molecular weight (M n ) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally providing an adhesive comprising a catalyst capable of catalyzing the reaction of OH groups with NCO groups; (2) mixing component A with component B to form an adhesive mixture; (3) applying the adhesive mixture to a first substrate; (4) bringing the first substrate into adhesive contact with a second substrate; (5) curing the adhesive mixture.

[0084] The ingredients of Components A and B useful in the method of the present invention are as described for the adhesive.

[0085] The mixing of components A and B is carried out by any method that allows a homogenous mixture to be obtained fairly rapidly. Typically, the mixing is obtained by simultaneously introducing both components into a mixing vessel or mixing channel. The mixing of components A and B can be in any desired ratio, but is typically carried out using an A:B volume ratio of 0.8 to 1.2, more preferably 1.

[0086] Application of the adhesive mixture to a substrate is typically performed using a suitable application gun and a static mixer. The adhesive is loaded into a cartridge that can ensure a suitable mix ratio. The cartridge is placed into the application gun and a suitable static mixer is attached. The adhesive is then extruded through the static mixer onto the surface to be bonded.

[0087] Curing is typically carried out at ambient temperature (eg, 23° C.) and humidity (eg, 50% relative humidity). Complete cure with the adhesives of the present invention usually occurs in 7-10 days.

[0088] There is no particular limit to the substrate, which may include metal and plastic. The adhesive of the present invention is particularly suitable for bonding e-coated steel, PET film, aluminum-deposited plastic film, and aluminum.

[0089] Preferred applications include thermally conductive materials for use in any application where thermally conductive materials are required, with a primary application being in the automotive industry, specifically in thermal management of EV batteries for bonding modules or cells to cooling plates.

[0090] [Effects of the invention] The cured adhesive of the present invention (7 days, 23° C., 50% RH) preferably has a bond area of ​​250 mm, measured according to DIN EN 1465. 2 (10 x 25 mm), adhesive layer thickness: 1 mm, using e-coated steel on both substrates, it shows a lap shear strength of more than 4 MPa.

[0091] The adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) preferably has a pot life of more than 60 minutes, more preferably more than 65 minutes. The pot life is the time until the rheological viscosity simultaneously reaches 900 Pas at a shear rate of 0.25 / s, 500 Pas at a shear rate of 1 / s, and 300 Pas at a shear rate of 2.5 / s. The rheological viscosity is measured using a TA rheometer with 25 mm parallel plates and a 0.2 mm gap.

[0092] The adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) preferably has, after curing for 7 days at 23°C and 50% RH, a tensile strength of less than or equal to 5 MPa, measured according to DIN EN ISO 527-2, when a sample is pulled at 50 mm / min.

[0093] The adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) preferably has, after curing for 7 days at 23° C. and 50% RH, an E modulus of less than or equal to 15, measured according to DIN EN ISO 527-2, when the sample is pulled at 50 mm / min.

[0094] The adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) preferably has, after curing for 7 days at 23° C. and 50% RH, an elongation at break of 100% or more, measured according to DIN EN ISO 527-2, when the sample is pulled at 50 mm / min.

[0095] Particularly preferred embodiments The following are particularly preferred embodiments of the adhesive composition of the present invention.

[0096] 1. A two-part thermally conductive polyurethane adhesive comprising: (A) Component A: (ai) Molecular weight (M n ) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.

[0097] 2. A kit for producing a thermally conductive polyurethane adhesive, comprising: (A) Component A: (ai) Molecular weight (M n) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally a catalyst capable of catalyzing the reaction of an OH group with an NCO group.

[0098] 3. A method for bonding two or more substrates, comprising: (1) (A) Component A: (ai) Molecular weight (M n ) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) optionally providing an adhesive comprising a catalyst capable of catalyzing the reaction of OH groups with NCO groups; (2) mixing component A with component B to form an adhesive mixture; (3) applying the adhesive mixture to a first substrate; (4) bringing the first substrate into adhesive contact with a second substrate; (5) curing the adhesive mixture.

[0099] 4. (1) a first substrate; (2) a second substrate adhered to the first substrate, The first substrate and the second substrate are (A) Component A: (ai) Molecular weight (M n ) greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45% by weight, based on the total weight of component A, of at least one polyisocyanate selected from aliphatic polyisocyanates and mixtures of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M n ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2, (bii) Optionally, the assemblies are bonded together by an adhesive produced by mixing with a catalyst capable of catalyzing the reaction of OH groups with NCO groups.

[0100] 5. The polyols used to prepare the prepolymers are polyether polyols, in particular poly(C 2~4 Any one of the preceding embodiments, wherein the polyol is selected from the group consisting of alkylene oxide (alkylene oxide) polyols.

[0101] 6. Any one of the preceding embodiments, wherein the polyol used to make the prepolymer is selected from a poly(propylene oxide) polyol.

[0102] 7. Any one of the preceding embodiments, wherein the polyol used to make the prepolymer has a functionality of 2.5 to 3, more preferably 3.

[0103] 8. Any one of the preceding embodiments, wherein the polyol used to make the prepolymer is a polyether polyol having a functionality of 2.5 to 3, more preferably 3.

[0104] 9. The polyol used to prepare the prepolymer is a poly(C 2~4 Any one of the preceding embodiments, wherein the polyol is an alkylene oxide (alkylene oxide) polyol.

[0105] 10. Any one of the preceding embodiments, wherein the polyol used to make the prepolymer is a poly(propylene oxide) polyol having a functionality of 2.5 to 3, more preferably 3.

[0106] 11. The polyol used to prepare the prepolymer has a molecular weight (M) of more than 2,500 Da. n ), and more preferably the polyol has a molecular weight (M n )

[0107] 12. The polyol used to prepare the prepolymer has a molecular weight (M) of more than 2,500 Da. n ), in particular poly(C 2~4 More preferably, it is selected from polyols having a molecular weight (M n )

[0108] 13. The polyol used to prepare the prepolymer has a molecular weight (M) of more than 2,500 Da. n ), more preferably it is selected from poly(propylene oxide) polyols having a molecular weight (M) of 3,000 Da. n )

[0109] 14. The polyol used to prepare the prepolymer has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ), more preferably it has a molecular weight (M n )

[0110] 15. The polyol used to prepare the prepolymer has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ), more preferably it is a polyether polyol having a molecular weight (M n )

[0111] 16. The polyol used to prepare the prepolymer has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ) having poly(C 2~4 More preferably, it is a polyol having a molecular weight (M) of 3,000 Da. n )

[0112] 17. The polyol used to prepare the prepolymer has a functionality of 2.5 to 3, more preferably 3, and a molecular weight (M) of more than 2,500 Da. n ), more preferably it is a poly(propylene oxide) polyol having a molecular weight (M) of 3,000 Da. n )

[0113] 18. Any one of the preceding embodiments, wherein the prepolymer is made with a mixture of polyols selected from those described herein.

[0114] 19. Any one of the preceding embodiments, wherein the polyisocyanate is selected from an aliphatic polyisocyanate and a mixture of 2,4'-MDI and 4,4'-MDI.

[0115] 20. Any one of the preceding embodiments, wherein the polyisocyanate is aliphatic, with isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), and hexamethylene diisocyanate (HDI), and mixtures thereof being particularly preferred.

[0116] 21. Any one of the preceding embodiments, wherein the polyisocyanate is a mixture of 2,4'-MDI and 4,4'-MDI.

[0117] 22. Any one of the preceding embodiments, wherein the polyisocyanate is a mixture of 2,4'-MDI and 4,4'-MDI, and the weight ratio of 2,4'-MDI to 4,4'-MDI is from 0.667 to 1.5, more particularly preferably from 0.8 to 1.5, and even more particularly preferably from 1 to 1.5.

[0118] 23. Any one of the preceding embodiments, wherein the polyisocyanate is a mixture of 2,4'-MDI and 4,4-MDI in a 1:1 weight ratio of 2,4'-MDI to 4,4-MDI.

[0119] 24. Any one of the preceding embodiments, wherein the prepolymer reaction mixture is used without purification.

[0120] 25. Any one of the preceding embodiments, wherein the at least one polyisocyanate is used in an amount such that it is in a 2 to 15-fold stoichiometric excess over the polyol, more preferably in an 8 to 12-fold stoichiometric excess over the polyol, and particularly preferably in a 10-fold stoichiometric excess over the polyol.

[0121] 26. Any one of the preceding embodiments, wherein the prepolymer is made by reacting a polyether polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0122] 27. The prepolymer is poly(C 2~4 Any one of the preceding embodiments, wherein the polyolefin is prepared by reacting an alkylene oxide (alkylene oxide) polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0123] 28. Any one of the preceding embodiments, wherein the prepolymer is made by reacting a poly(propylene oxide) polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0124] 29. Any one of the preceding embodiments, wherein the prepolymer is made by reacting a polyether polyol having a functionality of 2.5 to 3, more preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0125] 30. The prepolymer is a poly(C) having a functionality of 2.5 to 3, more preferably 3. 2~4 Any one of the preceding embodiments, wherein the polyolefin is prepared by reacting an alkylene oxide (alkylene oxide) polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0126] 31. Any one of the preceding embodiments, wherein the prepolymer is made by reacting a poly(propylene oxide) polyol having a functionality of 2.5 to 3, more preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0127] 32. The prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n Any one of the preceding embodiments, wherein the polyether polyol is made by reacting a polyether polyol having a molar ratio of 1:1 or 2:1 with a mixture of 2,4'-MDI and 4,4'-MDI.

[0128] 33. The prepolymer has a molecular weight (M) of more than 2,500 Da. n ), more preferably a molecular weight (M n ) having poly(C 2~4 Any one of the preceding embodiments, wherein the polyolefin is made by reacting an alkylene oxide (alkylene oxide) polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0129] 34. The prepolymer has a molecular weight (M) of more than 2,500 Da. n ), more preferably a molecular weight (M n Any one of the preceding embodiments, wherein the poly(propylene oxide) polyol is made by reacting a poly(propylene oxide) polyol having a molar ratio of 1:1 or 2:1 with a mixture of 2,4'-MDI and 4,4'-MDI.

[0130] 35. The prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ), and a polyether polyol having a functionality of 2.5 to 3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0131] 36. The prepolymer has a molecular weight (M) of more than 2,500 Da. n ), more preferably a molecular weight (M n ), and a polyether polyol having a functionality of 2.5 to 3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0132] 37. The prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n ), and poly(C 2~4 Any one of the preceding embodiments, wherein the polyolefin is made by reacting an alkylene oxide (alkylene oxide) polyol with a mixture of 2,4'-MDI and 4,4'-MDI.

[0133] 38. The prepolymer has a molecular weight (M n ), more preferably a molecular weight (M n Any one of the preceding embodiments, wherein the poly(propylene oxide) polyol is made by reacting a mixture of 2,4'-MDI and 4,4'-MDI with a functionality of 2.5 to 3, preferably 3.

[0134] 39. The prepolymer has a molecular weight (M) of more than 2,500 Da. n ), more preferably a molecular weight (M n), and a polyether polyol having a functionality of 2.5 to 3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.

[0135] 40. Any one of the preceding embodiments, wherein the prepolymer is made by reacting a poly(propylene oxide) polyol of molecular weight (Mn) 3,000 Da and functionality 3 with a 1:1 (wt:wt) mixture of 2,4'-MDI and 4,4'-MDI.

[0136] 41. Any one of the preceding embodiments, wherein the at least one polyol is used in component A in an amount of 10 to 40 wt.%, more preferably 25 to 35 wt.%, and particularly preferably 28 to 29 wt.%, based on the total weight of component A.

[0137] 42. Any one of the preceding embodiments, wherein the at least one polyisocyanate is used in component A in an amount of 20 to 50% by weight, more preferably 30 to 40% by weight, and more particularly preferably 34 to 36% by weight, based on the total weight of component A.

[0138] 43. Any one of the preceding embodiments, wherein the NCO-terminated prepolymer preferably comprises 40 to 50 wt. %, more preferably 42 to 48 wt. %, and especially preferably 43 to 45 wt. % polyol, based on the total weight of the prepolymer.

[0139] 44. Any one of the preceding embodiments, wherein the NCO-terminated prepolymer preferably comprises 50 to 60 wt. %, more preferably 52 to 58 wt. %, and especially preferably 54 to 56 wt. % diisocyanate, based on the total weight of the prepolymer.

[0140] 45. Any one of the preceding embodiments, wherein the prepolymer is used without purification.

[0141] 46. ​​Any one of the preceding embodiments, wherein the prepolymer mixture is used in component A at 50 to 75 wt. %, more preferably 55 to 70 wt. %, and more particularly preferably 60 to 66 wt. %, based on the total weight of component A.

[0142] 47. Any one of the preceding embodiments, wherein component A additionally comprises talc.

[0143] 48. Any one of the preceding embodiments, wherein component A comprises 25 to 40 wt. %, more preferably 30 to 40 wt. %, and particularly preferably 32 to 37 wt. % talc, based on the total weight of component A.

[0144] 49. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a polyol having a molecular weight (Mn) greater than 400 Da.

[0145] 50. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a polyol having a molecular weight (Mn) of 400 to 1,000 Da, more preferably 500 to 1,000 Da.

[0146] 51. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a polyol having a functionality of 3 or greater.

[0147] 52. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a polyol having a functionality of 3 or greater and having a molecular weight (Mn) of 400 to 1,000 Da, more preferably 500 to 1,000 Da.

[0148] 53. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a mixed polyol, particularly a mixture of a polyol having a functionality of 3 and a polyol having a functionality greater than 3.

[0149] 54. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a polyether polyol.

[0150] 55. At least one polyol in component B is poly(C 2~4 Any one of the preceding embodiments, comprising a polyol selected from poly(alkylene oxide)-based polyols, in particular poly(ethylene oxide)-based, poly(propylene oxide)-based, poly(butylene oxide)-based polyols, and mixtures thereof.

[0151] 56. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a polyol selected from poly(propylene oxide)-based polyols.

[0152] 57. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a triol.

[0153] 58. At least one polyol in component B is poly(C 2~4 Any one of the preceding embodiments, comprising a triol selected from poly(alkylene oxide)-based, particularly poly(propylene oxide)-based, or castor oil.

[0154] 59. Any one of the preceding embodiments, wherein at least one polyol in component B comprises castor oil.

[0155] 60. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a mixture of a polyether polyol and castor oil, particularly a mixture of a polyether polyol having a functionality greater than 3, more preferably greater than 4, and particularly preferably greater than 5, and castor oil.

[0156] 61. Embodiment 60, wherein the polyether polyol having a functionality greater than 3, more preferably greater than 4, and particularly preferably greater than 5, is a poly(propylene oxide) polyol.

[0157] 62. Any one of the preceding embodiments, wherein component B comprises 40-60% by weight of a triol, based on the total weight of component B.

[0158] 63. Any one of the preceding embodiments, wherein component B comprises 0-10 wt.% of a polyol having a functionality greater than 3, more preferably greater than 4.

[0159] 64. Any one of the preceding embodiments, wherein component B comprises 0-20 wt.% of a polyol having a functionality greater than 2, more preferably a functionality of 3, and a molecular weight less than 500 Da, more preferably less than 400 Da.

[0160] 65. Any one of the preceding embodiments, wherein component B comprises 40-60 wt.% of a triol, 0-10 wt.% of a polyol having a functionality greater than 3, more preferably greater than 4, and 0-20 wt.% of a polyol having a functionality greater than 2, more preferably a functionality of 3, and a molecular weight less than 500 Da, more preferably less than 400 Da, based on the total weight of component B.

[0161] 66. Any one of the preceding embodiments, wherein the at least one polyol in component B comprises a mixture of 80 to 97 wt.-%, more preferably 85 to 95 wt.-%, particularly preferably 91 to 94 wt.-% of castor oil and 3 to 20 wt.-%, more preferably 5 to 15 wt.-%, particularly preferably 6 to 9 wt.-% of a polyether polyol, in particular a polyether polyol having a functionality greater than 3, more preferably greater than 4, particularly preferably greater than 5 (wherein the wt.-% is based on the total weight of polyols in component B).

[0162] 67. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a mixture of 80 to 97 wt.-%, more preferably 85 to 95 wt.-%, particularly preferably 91 to 94 wt.-%, of a triol and 3 to 20 wt.-%, more preferably 5 to 15 wt.-%, particularly preferably 6 to 9 wt.-%, of a polyether polyol having a functionality greater than 3, more preferably greater than 4, particularly preferably greater than 5, based on the total weight of polyols in component B.

[0163] 68. Any one of the preceding embodiments, wherein at least one polyol in component B comprises a mixture of poly(propylene oxide) having a functionality of 6 and castor oil.

[0164] 69. Any one of the preceding embodiments, wherein the at least one polyol in component B comprises a mixture of 80 to 97 wt.%, more preferably 85 to 95 wt.%, and especially preferably 91 to 94 wt.%, of castor oil and 3 to 20 wt.%, more preferably 5 to 15 wt.%, and especially preferably 6 to 9 wt.%, of a poly(propylene oxide) polyol having a functionality of 6, where the wt.% are based on the total weight of polyols in component B.

[0165] 70. Any one of the preceding embodiments, wherein component B additionally comprises a catalyst capable of catalyzing the reaction of an isocyanate group with an OH group.

[0166] 71. Any one of the preceding embodiments, wherein the catalyst is dioctyltin mercaptide.

[0167] 72. Any one of the preceding embodiments, wherein the catalyst is used at 0.0005 to 0.002 wt %, more preferably 0.00075 to 0.0015 wt %, based on the total weight of component B.

[0168] 73. Any one of the preceding embodiments, wherein the catalyst is dioctyltin mercaptide used at 0.0005 to 0.002 wt %, more preferably 0.00075 to 0.0015 wt %, based on the total weight of component B.

[0169] 74. Any one of the preceding embodiments, wherein component B additionally comprises talc.

[0170] 75. Any one of the preceding embodiments, wherein component B additionally comprises 20 to 50 wt. %, more preferably 30 to 40 wt. %, and particularly preferably 30 to 34 wt. % of talc, based on the total weight of component B.

[0171] 76. Any one of the preceding embodiments, wherein the substrate includes metal and plastic.

[0172] 77. Any one of the preceding embodiments, wherein the substrate is selected from e-coated steel, PET film, aluminized plastic film, and aluminum.

[0173] 78, The cured adhesive of the present invention (preferably 1:1 volume ratio of component A to component B, curing: 7 days, 23°C, 50% RH) has a bonding area of ​​250 mm2 when measured according to DIN EN 1465. 2 (10×25 mm), adhesive layer thickness: 1 mm, and using e-coated steel on both substrates, any one of the preceding embodiments exhibiting a lap shear strength of 4 MPa or greater.

[0174] 79. Any one of the preceding embodiments, wherein the adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has a pot life of greater than 60 minutes, more preferably greater than 65 minutes.

[0175] 80. Any one of the preceding embodiments, wherein the adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has, after curing for 7 days at 23°C and 50% RH, a tensile strength of 5 MPa or less, measured according to DIN EN ISO 527-2, when a sample is pulled at 50 mm / min.

[0176] 81. Any one of the preceding embodiments, wherein the adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has, after curing for 7 days at 23°C and 50% RH, an E modulus of 15 or less, measured according to DIN EN ISO 527-2, when the sample is pulled at 50 mm / min.

[0177] 82. Any one of the preceding embodiments, wherein the adhesive mixture obtained by mixing component A with component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has, after curing for 7 days at 23°C and 50% RH, an elongation at break of 100% or more when the sample is pulled at 50 mm / min, measured according to DIN EN ISO 527-2. EXAMPLES

[0178] [Table 1]

[0179] Adhesive Formulation Component A (Isocyanate) Preparation of prepolymer The prepolymer was prepared in a 2 L, 4-neck flask equipped with a mechanical stirrer and thermometer. The isocyanate-terminated prepolymer was prepared by first mixing the polyol raw materials of Component A and stirring under reduced pressure at 120° C. for 1 hour. The polyol was cooled to 80° C., the isocyanate raw materials were added, and the mixture was allowed to react under reduced pressure at 80° C. for 2 hours. The material was then cooled to below 30° C. The vacuum was broken under nitrogen and the prepolymer was stored sealed until use.

[0180] A specific description of the prepolymer process is given with reference to Example 6 of the present invention. 568 g of NJ-330 was added to a 4-neck flask equipped with a mechanical stirrer and a thermometer at room temperature. NJ-300 was dried under vacuum at 120° C. for 1 hour. NJ-300 was cooled to 80° C., 712 g of MDI-50 was added to the flask, and the mixture was reacted under vacuum at 80° C. for 2 hours. The material was cooled to below 30° C. The vacuum was broken under nitrogen, and the prepolymer was stored sealed until use. The prepolymer was prepared with an excess of isocyanate, resulting in a predominantly NCO-terminated prepolymer.

[0181] To prepare Component A using the amounts listed in Table 2, talc and fumed silica were dried in a 120° C. oven for 24 hours or more until the moisture content was less than 300 ppm. The prepolymer was added to a 2 L planetary mixer and mixed for 10 minutes. The dry talc and silica were added and mixing was continued for an additional 30 minutes at room temperature. The vacuum was then broken under nitrogen and Component A was packaged in a sealed cartridge and stored until use.

[0182] A specific description of the preparation of component A is given with reference to Example 6 of the present invention. Solid talc and CAB-O-SIL TS-720 were dried in an oven at 120° C. for at least 24 hours until the moisture content was less than 300 ppm. 640 g of prepolymer, 345 g of talc, and 15 g of CAB-O-SIL were added to a 2 liter planetary mixer along with red pigment. After mixing for 30 minutes at room temperature, the vacuum was broken with nitrogen and the adhesive components can be filled into appropriate packaging sizes.

[0183] Component B (Polyol) To prepare Component B (polyol) using the amounts listed in Table 2, talc and CAB-O-SIL TS-720 were dried in an oven at 120° C. for over 24 hours until the moisture content was less than 300 ppm. The polyol was dried with molecular sieves until the moisture content was less than 300 ppm. The dry ingredients were mixed with the polyol and stirring was continued for 30 minutes. Molecular sieves and Fomrez UL-29 were added and stirring was continued for an additional 30 minutes. The vacuum was broken under nitrogen and Component B was filled into a closed cartridge until use.

[0184] Components A and B were stored separately until use. Immediately before use, the components were mixed in a 1:1 volume ratio and the following tests were performed.

[0185] pot life The pot life is the time until the rheological viscosity simultaneously reaches 900 Pas at a shear rate of 0.25 / s, 500 Pas at a shear rate of 1 / s, and 300 Pas at a shear rate of 2.5 / s. The results are listed in Table 2.

[0186] Rheological Viscosity The rheological viscosity is measured 60 minutes after mixing components A and B using a TA rheometer with 25 mm parallel plates and a 0.2 mm gap.

[0187] The results are listed in Table 2.

[0188] Lap shear strength Lap shear strength according to DIN EN 1465, adhesive area: 250 mm 2 (10×25 mm), adhesive layer thickness: 1 mm, were measured using e-coated steel on both substrates. Prior to adhesive application, all surfaces were prepared by cleaning with isopropanol. Curing conditions were 23°C at 50% RH for 7 days. During the test, the shear specimens were pulled at 5 mm / min. The results are listed in Table 2.

[0189] Tensile Properties Tensile strength, E modulus and elongation were measured according to DIN EN ISO 527-2. Curing conditions: 23° C. with 50% RH for 7 days. During the test process, the tensile samples were pulled at 50 mm / min. The results are listed in Table 2.

[0190] [Table 2]

[0191] [Table 3]

[0192] result Inventive Example 6 exhibits a pot life of greater than 60 minutes, while the comparative example exhibits a pot life of less than 60 minutes.

[0193] Inventive Example 6 exhibits a slower viscosity increase than the comparative example.

[0194] Inventive Example 6 exhibits greater elasticity (lower E modulus and higher elongation at break) than the comparative examples.

Claims

1. A two-part thermally conductive polyurethane adhesive comprising: (A) Component A: (ai) Molecular weight (M ｎ ) greater than 2,000 Da and at least one polyol having an OH functionality of 2 to 3 with 30 to 45 weight percent, based on the total weight of component A, of at least one polyisocyanate selected from an aliphatic polyisocyanate and a mixture of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M ｎ ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2; and (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups; Including, adhesive.

2. 1. A method for bonding two or more substrates, comprising: (1) providing an adhesive, the adhesive comprising: (A) Component A: (ai) Molecular weight (M ｎ ) greater than 2,000 Da and at least one polyol having an OH functionality of 2 to 3 with 30 to 45 weight percent, based on the total weight of component A, of at least one polyisocyanate selected from an aliphatic polyisocyanate and a mixture of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI; (B) Component B: (bi) Molecular weight (M ｎ ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2; and (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups; and (2) mixing component A with component B to form an adhesive mixture; (3) applying the adhesive mixture to a first substrate; (4) bringing the first substrate into adhesive contact with a second substrate; (5) curing the adhesive mixture; and A method comprising:

3. A bonded assembly comprising: (1) a first substrate; (2) a second substrate adhered to the first substrate; and Including, The first substrate and the second substrate are (A) Component A: (ai) Molecular weight (M ｎ ) greater than 2,000 Da and at least one polyol having an OH functionality of 2-3, with 30-45 wt. %, based on the total weight of component A, of an aliphatic polyisocyanate, a mixture of 2,4'-methylene-bis-(phenylisocyanate) (MDI) and 4,4'-MDI, and at least one polyisocyanate selected; (B) Component B: (bi) Molecular weight (M ｎ ) less than 1,000 Da and at least one polyol having an OH functionality of at least 2; and (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups; The assembly is bonded together by an adhesive produced by mixing

5. The polyol used to prepare the prepolymer is a polyether polyol, in particular poly(C ２～４ The adhesive, method or assembly of any one of claims 1 to 4, wherein the polyol is selected from the group consisting of alkylene oxide (alkylene oxide) polyols.

6. The adhesive, method or assembly of any one of claims 1 to 5, wherein the polyol used to make the prepolymer is selected from poly(propylene oxide) polyols.

7. The adhesive, method or assembly according to any one of claims 1 to 6, wherein the polyol used to make the prepolymer has a functionality of from 2.5 to 3, more preferably 3.

8. The adhesive, method or assembly according to any one of claims 1 to 7, wherein the polyol used to make the prepolymer is a polyether polyol having a functionality of 2.5 to 3, more preferably 3.

9. 9. The adhesive, process or assembly of any one of claims 1 to 8, wherein the polyol used to make the prepolymer is a poly(propylene oxide) polyol having a functionality of 2.5 to 3, more preferably 3.

10. The polyol used to prepare the prepolymer has a molecular weight (M ｎ ), and more preferably, the polyol has a molecular weight (M ｎ 10. The adhesive, method or assembly of claim 1, comprising:

11. The adhesive, method or assembly of any one of claims 1 to 10, wherein the polyisocyanate is a mixture of 2,4'-MDI and 4,4'-MDI.

12. 12. The adhesive, method or assembly according to any one of claims 1 to 11, wherein the polyisocyanate is a mixture of 2,4'-MDI and 4,4'-MDI, the weight ratio of 2,4'-MDI to 4,4'-MDI being from 0.667 to 1.5, more particularly preferably from 0.8 to 1.5, even more particularly preferably from 1 to 1.

5.

13. 13. The adhesive, process or assembly according to any one of claims 1 to 12, wherein the at least one polyol is used in component A in an amount of 10 to 40 wt.-%, more preferably 25 to 35 wt.-%, particularly preferably 28 to 29 wt.-%, based on the total weight of component A.

14. 14. The adhesive, process or assembly according to any one of the preceding claims, wherein the at least one polyisocyanate is used in component A in an amount of 20 to 50% by weight, more preferably 30 to 40% by weight, more particularly preferably 34 to 36% by weight, based on the total weight of component A.

15. The adhesive, method or assembly of any one of claims 1 to 14, wherein said at least one polyol in component B comprises a polyol having a molecular weight (Mn) greater than 400 Da.

16. The adhesive, method or assembly of any one of the preceding claims, wherein said at least one polyol in component B comprises a polyol having a molecular weight (Mn) of 400 to 1,000 Da, more preferably 500 to 1,000 Da.

17. The adhesive, method or assembly of any one of claims 1 to 16, wherein the at least one polyol in component B comprises a polyol having a functionality of 3 or greater.

18. 18. The adhesive, process or assembly according to any one of claims 1 to 17, wherein the at least one polyol in component B comprises a mixed polyol, in particular a mixture of a polyol with a functionality of 3 and a polyol with a functionality greater than 3.

19. The at least one polyol in component B is poly(C ２～４ 19. The adhesive, method or assembly of any one of claims 1 to 18, comprising a triol selected from poly(alkylene oxide) based, in particular poly(propylene oxide) based, or castor oil.

20. 20. The adhesive, method or assembly according to any one of the preceding claims, wherein the at least one polyol in component B comprises a mixture of a polyether polyol and castor oil, in particular a mixture of a polyether polyol having a functionality of more than 3, more preferably more than 4, particularly preferably more than 5, and castor oil.

Images