Two-component polyurethane adhesive composition
The problem of insufficient working time is solved by using NCO-capped prepolymers made by reacting high molecular weight polyols with isocyanate in two-component polyurethane adhesives and mixing them with low molecular weight polyols, and achieving more flexible Operate and stable curing effect.
Patent Information
- Application Number
- CN202280095983.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-05-12
- Publication Date
- 2024-12-20
AI Technical Summary
The limited working time of two-component polyurethane adhesives is difficult to meet the extended needs in some applications, affecting the flexibility and quality of the bonding process.
Using a combination of isocyanate components and polyol components, the NCO-capped prepolymer is prepared by reacting polyols with molecular weight greater than 2,000 Da with isocyanate and mixed with polyols with molecular weight less than 1,000 Da, and adding catalysts to prolong the work. Time and slow viscosity development.
The extended working time and slow viscosity development are achieved, the operating flexibility and curing quality of the adhesive are improved, and the greater working time and stable mechanical properties are provided.
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Abstract
Description
Technical Field
[0001] The present invention relates to the field of two-component polyurethane adhesive compositions. Background Art
[0002] Two-component polyurethane adhesives offer a wide variety of attachment means. In the automotive industry, their use is increasing, in part due to the desire to reduce the weight attributed to conventional attachment means such as rivets.
[0003] Two-component 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. Just before use, the two components are mixed, and the polyol OH groups are reacted with the NCO groups of the isocyanate-terminated molecules to form a higher molecular weight polyurethane, which can be linear or branched (i.e. cross-linked). Once the components are mixed and the molecular weight begins to increase, the viscosity of the mixture also increases. There is a limited time in which the adhesive mixture has a viscosity that allows the manipulation of the adhesive mixture and the parts bonded using the mixture. The time from mixing to the defined degree of cure (and / or viscosity) is referred to as "working time". For some applications, it is desirable to have an extended working time. Summary of the invention
[0004] In a first aspect, the present invention provides a two-component thermally conductive polyurethane adhesive comprising:
[0005] (A) Component A:
[0006] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0007] (B) Component B:
[0008] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0009] (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
[0010] In a second aspect, the present invention provides a kit for producing a thermally conductive polyurethane adhesive, the kit comprising:
[0011] (A) Component A:
[0012] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0013] (B) Component B:
[0014] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0015] (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
[0016] In a third aspect, the present invention provides a method for bonding two or more substrates, the method comprising the steps of:
[0017] (1) Providing an adhesive, the adhesive comprising:
[0018] (A) Component A:
[0019] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0020] (B) Component B:
[0021] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0022] (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups;
[0023] (2) mixing component A and component B to produce an adhesive mixture;
[0024] (3) applying the adhesive mixture to a first substrate;
[0025] (4) bringing the first substrate into bonding contact with the second substrate;
[0026] (5) Curing the adhesive mixture.
[0027] In a fourth aspect, the present invention provides a bonded assembly comprising:
[0028] (1) a first substrate;
[0029] (2) a second substrate bonded to the first substrate;
[0030] The first substrate and the second substrate are bonded to each other by an adhesive prepared by mixing the following component A and component B together:
[0031] (A) Component A:
[0032] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0033] (B) Component B:
[0034] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0035] (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups. DETAILED DESCRIPTION
[0036] The inventors have found that extended working time and slow viscosity development can be achieved in polyurethane adhesives by using an isocyanate component (component A) comprising a prepolymer having a molecular weight (M) of 1.5 to 2.5 and by using a polyol component. n ) greater than 2,000 Da and an OH functionality of 2 to 3 and 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A, the polyol component comprising a molecular weight (M n ) is at least one polyol having a molecular weight of less than 1,000 Da and an OH functionality of at least 2.
[0037] Definitions and Abbreviations
[0038] MDI Methylene-bis(phenyl isocyanate)
[0039] HDI Hexamethylene diisocyanate
[0040] IPDI Isophorone diisocyanate
[0041] PU Polyurethane
[0042] GPC Gel Permeation Chromatography
[0043] RH Relative humidity
[0044] Equivalent weight and molecular weight were measured by gel permeation chromatography (GPC) using a Malvern Viscothek GPC max device. Tetrahydrofuran (THF) was used as eluent, PL GEL MIXED D (Agilent, 300*7.5 mm, 5 μm) was used as a chromatographic column, and MALVERN Viscothek TDA (integrated refractive index viscometer and light scattering) was used as a detector.
[0045] Component A (isocyanate)
[0046] Component A comprises an NCO-terminated prepolymer, the NCO-terminated prepolymer being obtained by n ) is prepared by reacting at least one polyol having a molecular weight greater than 2,000 Da and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A.
[0047] The polyol is preferably selected from polyether polyols, in particular poly(C 2-4 -alkylene oxide) polyols.
[0048] In a preferred embodiment, the polyol is selected from poly(propylene oxide) polyols.
[0049] The polyol used to make the prepolymer preferably has a functionality of 2.5-3, more preferably 3.
[0050] In a preferred embodiment, the polyol used to make the prepolymer is a polyether polyol having a functionality of 2.5-3, more preferably 3.
[0051] In a more preferred embodiment, the polyol used to make the prepolymer is a poly(C 2-4 -alkylene oxide) polyols.
[0052] In another preferred embodiment, the polyol used to make the prepolymer is a poly(propylene oxide) polyol having a functionality of 2.5-3, more preferably 3.
[0053] In another preferred embodiment, the polyol used to make the prepolymer has a molecular weight (M) greater than 2,500 Da. n ), more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0054] In a preferred embodiment, the polyol used to make the prepolymer is selected from polyether polyols, especially polyols with a molecular weight (M n ) Poly(C) larger than 2,500 Da 2-4 -alkylene oxide) polyol, more preferably it has a molecular weight (M) of 3,000 Da n ).
[0055] In a preferred embodiment, the polyol is selected from n ) is greater than 2,500 Da, more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0056] The polyol used to make the prepolymer preferably has a functionality of 2.5-3, more preferably 3, and has a molecular weight (M) greater than 2,500 Da. n ), more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0057] In a preferred embodiment, the polyol used to make the prepolymer is a polyol with a functionality of 2.5-3, more preferably 3, and a molecular weight (M n ) greater than 2,500 Da, more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0058] In a more preferred embodiment, the polyol used to make the prepolymer is a polyol with a functionality of 2.5-3, more preferably 3, and a molecular weight (M n ) Poly(C) larger than 2,500 Da 2-4 -alkylene oxide) polyol, more preferably it has a molecular weight (M) of 3,000 Da n ).
[0059] In another preferred embodiment, the polyol used to make the prepolymer is a polyol with a functionality of 2.5-3, more preferably 3, and a molecular weight (M n ) is greater than 2,500 Da, more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0060] The prepolymer may be made with a mixture of polyols selected from those described herein.
[0061] The polyisocyanate is selected from aliphatic polyisocyanates and a mixture of 2,4'-MDI and 4,4'-MDI.
[0062] In a preferred embodiment, the polyisocyanate is aliphatic, with isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI) and hexamethylene diisocyanate (HDI) and mixtures of these being particularly preferred.
[0063] 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 0.667-1.5, more particularly preferably 0.8-1.5, even more particularly preferably 1-1.5.
[0064] Particularly preferred are mixtures of 2,4'-MDI and 4,4-MDI, wherein the weight ratio of 2,4'-MDI to 4,4-MDI is 1:1.
[0065] The NCO-terminated prepolymer of component A is 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, at least one polyol is first dried under vacuum and high temperature (>100° C.), and cooled (e.g., cooled to 80° C.), and then at least one polyisocyanate is added under vacuum. The mixture is reacted under vacuum for 1-2 hours. However, the prepolymer can be purified, and preferably, the resulting reaction mixture is used without purification.
[0066] At least one polyisocyanate is used in an amount such that the NCO groups are in excess relative to the OH groups of the polyol. In a preferred embodiment, at least one polyisocyanate is used in a 2-15-fold stoichiometric excess relative to the polyol, more preferably in an 8-12-fold stoichiometric excess relative to the polyol, particularly preferably in a 10-fold stoichiometric excess relative to the polyol.
[0067] In a preferred embodiment, the prepolymer is made by reacting a polyether polyol with a mixture of 2,4'-MDI and 4,4'-MDI.
[0068] In another preferred embodiment, the prepolymer is prepared by poly(C 2-4 It is prepared by reacting a mixture of alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0069] 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.
[0070] In another preferred embodiment, 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.
[0071] In another preferred embodiment, the prepolymer is prepared by mixing a poly(C 2-4 It is prepared by reacting a mixture of -alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0072] 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.
[0073] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is prepared by reacting a polyether polyol having a molecular weight of 3,000 Da with a mixture of 2,4'-MDI and 4,4'-MDI.
[0074] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is a 3,000Da poly(C 2-4 It is prepared by reacting a mixture of -alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0075] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is prepared by reacting a poly(propylene oxide) polyol having a molecular weight of 3,000 Da with a mixture of 2,4'-MDI and 4,4'-MDI.
[0076] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is 3,000 Da and the functionality is 2.5-3, preferably 3, and a mixture of 2,4'-MDI and 4,4'-MDI is reacted to make it.
[0077] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (Mn ) greater than 2,500 Da, more preferably a molecular weight (M n ) is 3,000 Da and the functionality is 2.5-3, preferably 3, and a mixture of 2,4'-MDI and 4,4'-MDI is reacted to make it.
[0078] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is 3,000 Da and has a functionality of 2.5-3, preferably 3 poly(C 2-4 It is prepared by reacting a mixture of -alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0079] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) of 3,000 Da and a functionality of 2.5 to 3, preferably 3, is reacted with a mixture of 2,4'-MDI and 4,4'-MDI.
[0080] In another preferred embodiment, the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is 3,000 Da and the functionality is 2.5-3, preferably 3, and a mixture of 2,4'-MDI and 4,4'-MDI is reacted to make it.
[0081] In a particularly preferred embodiment, the prepolymer is made by reacting a poly(propylene oxide) polyol having a molecular weight (Mn) of 3,000 Da and a functionality of 3 with a 1:1 (wt:wt) mixture of 2,4'-MDI and 4,4'-MDI.
[0082] At least one polyol is preferably used in component A at 10-40 wt%, more preferably 25-35 wt%, particularly preferably 28-29 wt%, based on the total weight of component A, it being understood that the polyol is in the form of a prepolymer.
[0083] The at least one polyisocyanate is used in component A in an amount of 20 to 50 wt %, based on the total weight of component A, more preferably 30 to 40 wt %, very particularly preferably 34 to 36 wt %.
[0084] The NCO-terminated prepolymer preferably comprises 40 to 50 wt % of polyol, more preferably 42 to 48 wt %, particularly preferably 43 to 45 wt % of polyol, based on the total weight of the prepolymer.
[0085] The NCO-terminated prepolymer preferably comprises 50 to 60 wt %, more preferably 52 to 58 wt %, particularly preferably 54 to 56 wt %, of diisocyanate, based on the total weight of the prepolymer.
[0086] The prepolymer is preferably used without purification. The prepolymer mixture is preferably used in component A in an amount of 50-75 wt %, based on the total weight of component A, more preferably 55-70 wt %, very particularly preferably 60-66 wt %.
[0087] Component A may additionally comprise talc. If used, talc is preferably present in an amount of 25-40 wt %, based on the total weight of component A, more preferably 30-40 wt %, particularly preferably 32-37 wt %.
[0088] Component A may additionally comprise fumed silica. If used, fumed silica is preferably present at 0.75-2 wt%, based on the total weight of component A, more preferably 1-2 wt%.
[0089] Component A is typically prepared by drying solid ingredients such as talc and fumed silica at high temperature under vacuum. Preferably, drying is performed until the moisture content is 300 ppm or less. The prepolymer is added to the dry ingredients and mixed to uniformity under reduced pressure, and then component A is stored in a moisture-proof container.
[0090] Component B (polyol)
[0091] Component B contains (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
[0092] The at least one polyol preferably comprises a polyol having a molecular weight (Mn) greater than 400 Da. Preferably, the at least one polyol comprises a polyol having a molecular weight (Mn) of 400-1,000 Da, more preferably 500-1,000 Da.
[0093] In preferred embodiments, the at least one polyol comprises a polyol having a functionality of 3 or more.
[0094] In a more preferred embodiment, the at least one polyol comprises a polyol having a functionality of 3 or more and a molecular weight (Mn) of 400-1,000 Da, more preferably 500-1,000 Da.
[0095] In a more preferred embodiment, the at least one polyol comprises a polyol mixture, in particular a mixture of a polyol having a functionality of three and a polyol having a functionality greater than three.
[0096] In a preferred embodiment, at least one polyol comprises a polyether polyol. Preferred polyether polyols are selected from poly(C 2-4 The polyols are preferably polyols based on poly(ethylene oxide), polyols based on poly(propylene oxide), polyols based on poly(butylene oxide) and mixtures of these. In a particularly preferred embodiment, the polyether polyol is selected from polyols based on poly(propylene oxide).
[0097] In another preferred embodiment, at least one polyol comprises a triol. The triol may be, for example, based on poly(C 2-4 -alkylene oxide), in particular based on poly(propylene oxide), or it may be, for example, castor oil. In a particularly preferred embodiment, the triol is castor oil.
[0098] 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 greater than 3, more preferably greater than 4, particularly preferably greater than 5, and castor oil.
[0099] 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.
[0100] In a preferred embodiment, component B comprises 40-60 wt % of triol based on the total weight of component B.
[0101] In a preferred embodiment, component B comprises 0-10 wt% of a polyol having a functionality greater than 3, more preferably greater than 4.
[0102] In a preferred embodiment, 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.
[0103] In another preferred embodiment, component B comprises 40-60 wt% of triols, 0-10 wt% of polyols having a functionality greater than 3, more preferably greater than 4, and 0-20 wt% of polyols 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.
[0104] In another preferred embodiment, the at least one polyol comprises a mixture of 80-97 wt %, more preferably 85-95 wt %, particularly preferably 91-94 wt % of castor oil and 3-20 wt %, more preferably 5-15 wt %, particularly preferably 6-9 wt % of polyether polyols, in particular polyether polyols 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 the polyols in component B.
[0105] In another preferred embodiment, the at least one polyol comprises a mixture of 80-97 wt %, more preferably 85-95 wt %, particularly preferably 91-94 wt % of triols and 3-20 wt %, more preferably 5-15 wt %, particularly preferably 6-9 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 the polyols in component B.
[0106] In a particularly preferred embodiment, at least one polyol comprises a mixture of poly(propylene oxide) having a functionality of 6 and castor oil.
[0107] In another particularly preferred embodiment, the at least one polyol comprises a mixture of 80-97 wt %, more preferably 85-95 wt %, particularly preferably 91-94 wt % of castor oil and 3-20 wt %, more preferably 5-15 wt %, particularly preferably 6-9 wt % of a poly(propylene oxide) polyol having a functionality of 6, wherein the wt % is based on the total weight of the polyols in component B.
[0108] Component B may additionally optionally comprise a catalyst which is able to catalyze the reaction of isocyanate groups with OH groups.
[0109] Examples of such catalysts include tertiary amine catalysts, organic metal catalysts such as bismuth catalysts, alkyltin carboxylates, alkyltin oxides, and tin mercaptides.
[0110] 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-dimorpholino-diethyl ether (DMDEE), N,N,N-dimethylaminopropylhexahydrotriazine, dimethyltetrahydropyrimidine, tetramethylethylenediamine, dimethylcyclohexylamine, 2,2-N,N-benzyldimethylamine, dimethylethanolamine , dimethylaminopropylamine, penta-dimethyldiethylenetriamine, 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, NN-dimethyldipropylenetriamine, N,N,N'-trimethylaminoethylethanolamine, among which DMDEE is particularly preferred.
[0111] If an organometallic catalyst is used, it is any organometallic catalyst capable of catalyzing the reaction of an isocyanate with a functional group having at least one reactive hydrogen. Examples include bismuth catalysts, metal carboxylates such as tin carboxylates and zinc carboxylates. 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 mercaptides, dimethyltin carboxylates, dimethyltin dioleate, dimethyltin dithioglycolate, dibutyltin mercaptides, dibutyltin bis(2-ethylhexyl thioglycolate), dibutyltin sulfide, dioctyltin dithioglycolate, dioctyltin mercaptides, dioctyltin dioctoate, dioctyltin dineodecanoate, dioctyltin dilaurate. In a preferred embodiment, the catalyst is a tin catalyst, particularly preferably dioctyltin mercaptides and / or dimethyltin dithioglycolate. In a particularly preferred embodiment, the catalyst is dioctyltin mercaptides.
[0112] The catalyst is preferably used in an amount of 0.0005 wt% to 0.002 wt%, based on the total weight of component B, more preferably 0.00075 wt% to 0.0015 wt%.
[0113] In a preferred embodiment, the catalyst is dioctyltin mercaptan, which is used at 0.0005 wt % to 0.002 wt %, more preferably 0.00075 wt % to 0.0015 wt %, based on the total weight of component B.
[0114] Component B may additionally comprise talc. If used, talc is preferably present in an amount of 20-50 wt %, based on the total weight of component B, more preferably 30-40 wt %, particularly preferably 30-34 wt %.
[0115] Component B may additionally comprise fumed silica. If used, fumed silica is preferably present at 0.75-2 wt%, based on the total weight of component A, more preferably 1-2 wt%.
[0116] Component B may additionally contain a water scavenger, such as a molecular sieve. If used, the molecular sieve is preferably used at 1-5 wt%, based on the total weight of component B, more preferably 2-4 wt%.
[0117] Component B is typically prepared by drying solid ingredients such as talc and fumed silica at high temperatures under vacuum. Preferably, drying is performed until the moisture content is 300 ppm or less. At least one polyol and a catalyst are added to the dry ingredients and mixed to uniformity under reduced pressure, and then component B is stored in a moisture-proof container.
[0118] Manufacturing method
[0119] The adhesive composition of the present invention is prepared by mixing the ingredients of each component individually, preferably under inert and dry conditions and / or under vacuum until a homogeneous mixture is obtained. Once the components are prepared, they are stored in separate containers until use.
[0120] How to use
[0121] In one aspect, the present invention provides a method for bonding two or more substrates, the method comprising the steps of:
[0122] (1) Providing an adhesive, the adhesive comprising:
[0123] (A) Component A:
[0124] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0125] (B) Component B:
[0126] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0127] (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups;
[0128] (2) mixing component A and component B to produce an adhesive mixture;
[0129] (3) applying the adhesive mixture to a first substrate;
[0130] (4) bringing the first substrate into bonding contact with the second substrate;
[0131] (5) Curing the adhesive mixture.
[0132] The ingredients of Part A and Part B that can be used in the process of the present invention are as described for the adhesive.
[0133] The mixing of component A and component B is carried out by any method that can achieve a uniform mixture fairly quickly. Typically, mixing is achieved by dispensing the two components simultaneously into a mixing vessel or channel. The mixing of component A and component B can be in any desired ratio, but typically uses a volume ratio of A:B of 0.8-1.2, more preferably 1.
[0134] Applying the adhesive mixture to the substrate is typically done using a suitable application gun and a static mixer. The adhesive is filled in a cartridge, which ensures a suitable mixing ratio. The cartridge is placed in the application gun and a suitable static mixer is installed. The adhesive is then pressed onto the surface to be bonded through the static mixer.
[0135] Curing is typically carried out at ambient temperature (eg, 23°C) and humidity (eg, 50% relative humidity).Full cure with the adhesives of the present invention typically occurs within 7-10 days.
[0136] The substrate is not particularly limited and includes metals and plastics. The adhesive of the present invention is particularly suitable for bonding e-coated steel, PET film, aluminized plastic film, aluminum.
[0137] Preferred applications include thermally conductive materials for use in any application where a thermally conductive material is required, with a major application in the automotive industry for thermal management of EV batteries; in particular for bonding modules or battery cells to cooling plates.
[0138] Effects of the Invention
[0139] The cured adhesives of the present invention preferably exhibit a lap shear strength of 4 MPa or more when measured according to DIN EN 1465 (7 days, 23° C., 50% RH), wherein the bonded area is 250 mm 2 (10X 25mm), adhesive layer thickness was 1mm, and electro-coated steel was used for both substrates.
[0140] The adhesive mixture obtained by mixing component A and component B (preferably with a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) preferably has a working time greater than 60 minutes, more preferably greater than 65 minutes. The working time is the time when the rheological viscosity reaches 900Pas at a shear rate of 0.25 / s, 500Pas at a shear rate of 1 / s, and 300Pas at a shear rate of 2.5 / s simultaneously. The rheological viscosity is measured using a TA rheometer with 25mm parallel plates and a 0.2mm gap.
[0141] The adhesive mixture obtained by mixing component A and component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) after curing for 7 days at 23°C and 50% RH, preferably has a tensile strength of 5 MPa or less when measured according to DIN EN ISO 527-2 and pulling the sample at 50 mm / min.
[0142] The adhesive mixture obtained by mixing component A and component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) after curing for 7 days at 23°C and 50% RH, preferably has an elastic modulus of 15 or less when measured according to DIN EN ISO 527-2 and pulling the sample at 50 mm / min.
[0143] The adhesive mixture obtained by mixing component A and component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) after curing for 7 days at 23°C and 50% RH, preferably has an elongation at break of 100% or more when measured according to DIN EN ISO 527-2 and pulling the sample at 50 mm / min.
[0144] Particularly preferred embodiments
[0145] The following are particularly preferred embodiments of the adhesive composition of the present invention:
[0146] 1. A two-component thermally conductive polyurethane adhesive comprising:
[0147] (A) Component A:
[0148] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0149] (B) Component B:
[0150] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0151] (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
[0152] 2. A kit for producing a thermally conductive polyurethane adhesive, comprising:
[0153] (A) Component A:
[0154] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0155] (B) Component B:
[0156] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0157] (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
[0158] 3. A method for bonding two or more substrates, the method comprising the steps of:
[0159] (1) Providing an adhesive, the adhesive comprising:
[0160] (A) Component A:
[0161] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0162] (B) Component B:
[0163] (bi) molecular weight (M n) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0164] (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups;
[0165] (2) mixing component A and component B to produce an adhesive mixture;
[0166] (3) applying the adhesive mixture to a first substrate;
[0167] (4) bringing the first substrate into bonding contact with the second substrate;
[0168] (5) Curing the adhesive mixture.
[0169] 4. A bonded assembly comprising:
[0170] (1) a first substrate;
[0171] (2) a second substrate bonded to the first substrate;
[0172] The first substrate and the second substrate are bonded to each other by an adhesive prepared by mixing the following component A and component B together:
[0173] (A) Component A:
[0174] (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A;
[0175] (B) Component B:
[0176] (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and
[0177] (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
[0178] 5. As described in any of the preceding embodiments, the polyol used to make the prepolymer is selected from polyether polyols, in particular poly(C 2-4 -alkylene oxide) polyols.
[0179] 6. As described in any preceding embodiment, wherein the polyol used to make the prepolymer is selected from poly(propylene oxide) polyols.
[0180] 7. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer has a functionality of 2.5-3, more preferably 3.
[0181] 8. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer is a polyether polyol having a functionality of 2.5-3, more preferably 3.
[0182] 9. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer is a poly(C 2-4 -alkylene oxide) polyols.
[0183] 10. As described in any preceding embodiment, wherein the polyol used to make the prepolymer is a poly(propylene oxide) polyol having a functionality of 2.5-3, more preferably 3.
[0184] 11. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer has a molecular weight (M) greater than 2,500 Da. n ), more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0185] 12. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer is selected from n ) greater than 2,500 Da, especially poly(C 2-4 -alkylene oxide) polyol, more preferably it has a molecular weight (M) of 3,000 Da n ).
[0186] 13. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer is selected from n ) is greater than 2,500 Da, more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0187] 14. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer has a functionality of 2.5-3, more preferably 3, and has a molecular weight (M) greater than 2,500 Da. n ), more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0188] 15. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer is a polyol with a functionality of 2.5-3, more preferably 3, a molecular weight (M n ) greater than 2,500 Da, more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0189] 16. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer is a polyol with a functionality of 2.5-3, more preferably 3, a molecular weight (M n ) Poly(C) larger than 2,500 Da 2-4 -alkylene oxide) polyol, more preferably it has a molecular weight (M) of 3,000 Da n ).
[0190] 17. As described in any of the preceding embodiments, wherein the polyol used to make the prepolymer is a polyol with a functionality of 2.5-3, more preferably 3, a molecular weight (M n ) is greater than 2,500 Da, more preferably it has a molecular weight (M) of 3,000 Da. n ).
[0191] 18. As described in any preceding embodiment, wherein the prepolymer is made from a mixture of polyols selected from those described herein.
[0192] 19. As described in any preceding embodiment, the polyisocyanate is selected from aliphatic polyisocyanates and a mixture of 2,4'-MDI and 4,4'-MDI.
[0193] 20. As described in any preceding embodiment, wherein the polyisocyanate is aliphatic, with isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI) and hexamethylene diisocyanate (HDI) and mixtures of these being particularly preferred.
[0194] 21. As described in any preceding embodiment, the polyisocyanate is a mixture of 2,4'-MDI and 4,4'-MDI.
[0195] 22. As described in any of the preceding embodiments, 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 0.667-1.5, more particularly preferably 0.8-1.5, even more particularly preferably 1-1.5.
[0196] 23. As described in any preceding embodiment, the polyisocyanate is a mixture of 2,4'-MDI and 4,4-MDI, wherein the weight ratio of 2,4'-MDI to 4,4-MDI is 1:1.
[0197] 24. As described in any preceding embodiment, wherein the prepolymer reaction mixture is used without purification.
[0198] 25. As described in any preceding embodiment, wherein the at least one polyisocyanate is used in an amount such that there is a 2-15-fold stoichiometric excess relative to the polyol, more preferably an 8-12-fold stoichiometric excess relative to the polyol, particularly preferably a 10-fold stoichiometric excess relative to the polyol.
[0199] 26. As described in any preceding embodiment, the prepolymer is made by reacting a polyether polyol with a mixture of 2,4'-MDI and 4,4'-MDI.
[0200] 27. As described in any of the preceding embodiments, wherein the prepolymer is prepared by poly(C 2-4 It is prepared by reacting a mixture of alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0201] 28. Any preceding embodiment wherein the prepolymer is made by reacting a poly(propylene oxide) polyol with a mixture of 2,4'-MDI and 4,4'-MDI.
[0202] 29. As described in any preceding embodiment, the prepolymer is made by reacting a polyether polyol having a functionality of 2.5-3, more preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.
[0203] 30. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making a poly(C 2-4 It is prepared by reacting a mixture of -alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0204] 31. As in any preceding embodiment, wherein the prepolymer is made by reacting a poly(propylene oxide) polyol having a functionality of 2.5-3, more preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.
[0205] 32. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n) is prepared by reacting a polyether polyol having a molecular weight of 3,000 Da with a mixture of 2,4'-MDI and 4,4'-MDI.
[0206] 33. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is a 3,000Da poly(C 2-4 It is prepared by reacting a mixture of -alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0207] 34. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is prepared by reacting a poly(propylene oxide) polyol having a molecular weight of 3,000 Da with a mixture of 2,4'-MDI and 4,4'-MDI.
[0208] 35. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is 3,000 Da and the functionality is 2.5-3, preferably 3, and a mixture of 2,4'-MDI and 4,4'-MDI is reacted to make it.
[0209] 36. As described in any preceding embodiment, the prepolymer is made by reacting a polyether polyol having a molecular weight (Mn) greater than 2,500 Da, more preferably a molecular weight (Mn) of 3,000 Da, and a functionality of 2.5-3, preferably 3, with a mixture of 2,4'-MDI and 4,4'-MDI.
[0210] 37. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is 3,000 Da and has a functionality of 2.5-3, preferably 3 poly(C 2-4 It is prepared by reacting a mixture of -alkylene oxide) polyols with 2,4'-MDI and 4,4'-MDI.
[0211] 38. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) of 3,000 Da and a functionality of 2.5 to 3, preferably 3, is reacted with a mixture of 2,4'-MDI and 4,4'-MDI.
[0212] 39. As described in any of the preceding embodiments, wherein the prepolymer is prepared by making the molecular weight (M n ) greater than 2,500 Da, more preferably a molecular weight (M n ) is 3,000 Da and the functionality is 2.5-3, preferably 3, and a mixture of 2,4'-MDI and 4,4'-MDI is reacted to make it.
[0213] 40. As described in any preceding embodiment, the prepolymer is made by reacting a poly(propylene oxide) polyol having a molecular weight (Mn) of 3,000 Da and a functionality of 3 with a 1:1 (wt:wt) mixture of 2,4'-MDI and 4,4'-MDI.
[0214] 41. As described in any of the preceding embodiments, wherein the at least one polyol is used in component A in an amount of 10-40 wt%, more preferably 25-35 wt%, particularly preferably 28-29 wt%, based on the total weight of component A.
[0215] 42. As described in any of the preceding embodiments, wherein the at least one polyisocyanate is used in component A in an amount of 20-50 wt%, more preferably 30-40 wt%, and more particularly preferably 34-36 wt%, based on the total weight of component A.
[0216] 43. As described in any of the preceding embodiments, the NCO-terminated prepolymer preferably comprises 40-50 wt% of the polyol, more preferably 42-48 wt%, particularly preferably 43-45 wt% of the polyol, based on the total weight of the prepolymer.
[0217] 44. As described in any of the preceding embodiments, the NCO-terminated prepolymer preferably comprises 50-60 wt% of diisocyanate, more preferably 52-58 wt%, particularly preferably 54-56 wt% of diisocyanate based on the total weight of the prepolymer.
[0218] 45. As described in any preceding embodiment, wherein the prepolymer is used without purification.
[0219] 46. As described in any preceding embodiment, wherein the prepolymer mixture is used in component A in an amount of 50-75 wt%, more preferably 55-70 wt%, and more preferably 60-66 wt%, based on the total weight of component A.
[0220] 47. As described in any preceding embodiment, wherein component A additionally comprises talc.
[0221] 48. As described in any of the preceding embodiments, wherein component A comprises 25-40 wt%, more preferably 30-40 wt%, and particularly preferably 32-37 wt% of talc based on the total weight of component A.
[0222] 49. As described in any preceding embodiment, wherein the at least one polyol in Component B comprises a polyol having a molecular weight (Mn) greater than 400 Da.
[0223] 50. As described in any preceding embodiment, wherein the at least one polyol in component B comprises a polyol having a molecular weight (Mn) of 400-1,000 Da, more preferably 500-1,000 Da.
[0224] 51. As described in any preceding embodiment, wherein the at least one polyol in Component B comprises a polyol having a functionality of 3 or more.
[0225] 52. As described in any preceding embodiment, wherein the at least one polyol in component B comprises a polyol having a functionality of 3 or more and a molecular weight (Mn) of 400-1,000 Da, more preferably 500-1,000 Da.
[0226] 53. As described in any preceding embodiment, wherein the at least one polyol in component B comprises a mixture of polyols, in particular a mixture of a polyol having a functionality of 3 and a polyol having a functionality greater than 3.
[0227] 54. As described in any preceding embodiment, wherein the at least one polyol in Component B comprises a polyether polyol.
[0228] 55. As described in any of the preceding embodiments, wherein the at least one polyol in component B comprises a polyol selected from the group consisting of 2-4 The invention also relates to polyols based on poly(ethylene oxide), polyols based on poly(propylene oxide), polyols based on poly(butylene oxide), and mixtures of these.
[0229] 56. As described in any preceding embodiment, wherein the at least one polyol in Component B comprises a polyol selected from poly(propylene oxide)-based polyols.
[0230] 57. As described in any preceding embodiment, wherein the at least one polyol in Component B comprises a triol.
[0231] 58. As described in any of the preceding embodiments, wherein the at least one polyol in component B comprises a triol selected from the group consisting of poly(C 2-4 -alkylene oxide) triols, in particular triols based on poly(propylene oxide) or castor oil.
[0232] 59. As described in any preceding embodiment, wherein the at least one polyol in Component B comprises castor oil.
[0233] 60. As described in any of the preceding embodiments, wherein the at least one polyol in component B comprises a mixture of polyether polyol and castor oil, in particular a mixture of polyether polyol and castor oil having a functionality greater than 3, more preferably greater than 4, and particularly preferably greater than 5.
[0234] 61. As described in embodiment 60, 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.
[0235] 62. As described in any preceding embodiment, wherein component B comprises 40-60 wt% of a triol based on the total weight of component B.
[0236] 63. As described in any preceding embodiment, wherein component B comprises 0-10 wt% of a polyol having a functionality greater than 3, more preferably greater than 4.
[0237] 64. As described in any preceding embodiment, 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.
[0238] 65. As described in any of the preceding embodiments, wherein component B comprises 40-60 wt% of triols, 0-10 wt% of polyols having a functionality greater than 3, more preferably greater than 4, and 0-20 wt% of polyols 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.
[0239] 66. As described in any of the preceding embodiments, the at least one polyol in component B comprises a mixture of 80-97 wt%, more preferably 85-95 wt%, particularly preferably 91-94 wt% castor oil and 3-20 wt%, more preferably 5-15 wt%, particularly preferably 6-9 wt% polyether polyols, in particular polyether polyols 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 the polyols in component B.
[0240] 67. As described in any of the preceding embodiments, the at least one polyol in component B comprises a mixture of 80-97 wt%, more preferably 85-95 wt%, particularly preferably 91-94 wt% of triols and 3-20 wt%, more preferably 5-15 wt%, particularly preferably 6-9 wt% of a polyether polyol having a functionality greater than 3, more preferably greater than 4, and particularly preferably greater than 5, based on the total weight of the polyols in component B.
[0241] 68. As described in any preceding embodiment, wherein the at least one polyol in Component B comprises a mixture of poly(propylene oxide) having a functionality of 6 and castor oil.
[0242] 69. As described in any of the preceding embodiments, the at least one polyol in component B comprises a mixture of 80-97 wt%, more preferably 85-95 wt%, particularly preferably 91-94 wt% of castor oil and 3-20 wt%, more preferably 5-15 wt%, particularly preferably 6-9 wt% of a poly(propylene oxide) polyol having a functionality of 6, wherein the wt% is based on the total weight of the polyols in component B.
[0243] 70. As described in any preceding embodiment, wherein component B additionally comprises a catalyst capable of catalyzing the reaction of isocyanate groups with OH groups.
[0244] 71. As described in any preceding embodiment, the catalyst is dioctyltin mercaptan.
[0245] 72. As described in any of the preceding embodiments, the catalyst is used at 0.0005 wt% to 0.002 wt%, more preferably 0.00075 wt% to 0.0015 wt%, based on the total weight of component B.
[0246] 73. As described in any preceding embodiment, the catalyst is dioctyltin mercaptan, which is used at 0.0005 wt% to 0.002 wt%, more preferably 0.00075 wt% to 0.0015 wt%, based on the total weight of component B.
[0247] 74. As described in any preceding embodiment, wherein Component B additionally comprises talc.
[0248] 75. As described in any of the preceding embodiments, wherein component B additionally comprises 20-50 wt %, more preferably 30-40 wt %, particularly preferably 30-34 wt %, of talc, based on the total weight of component B.
[0249] 76. Any preceding embodiment, wherein the substrate comprises metal and plastic.
[0250] 77. Any preceding embodiment, wherein the substrate is selected from the group consisting of electro-coated steel, PET film, aluminized plastic film, and aluminum.
[0251] 78. As described in any of the preceding embodiments, wherein the cured adhesive of the present invention (preferably a 1:1 volume ratio of component A to component B, cure: 7 days, 23° C., 50% RH) exhibits a lap shear strength of 4 MPa or greater when measured according to DIN EN 1465, wherein the bonded area: 250 mm 2 (10X 25mm), adhesive layer thickness was 1mm, and electro-coated steel was used for both substrates.
[0252] 79. As described in any preceding embodiment, the adhesive mixture obtained by mixing component A and component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has a working time greater than 60 minutes, more preferably greater than 65 minutes.
[0253] 80. As described in any of the preceding embodiments, the adhesive mixture obtained by mixing component A and component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has a tensile strength of 5 MPa or less after curing for 7 days at 23°C and 50% RH when measured according to DIN EN ISO 527-2 and pulling the sample at 50 mm / min.
[0254] 81. As described in any of the preceding embodiments, the adhesive mixture obtained by mixing component A and component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has an elastic modulus of 15 or less after curing for 7 days at 23°C and 50% RH when measured according to DIN EN ISO 527-2 and pulling the sample at 50 mm / min.
[0255] 82. As described in any of the preceding embodiments, the adhesive mixture obtained by mixing component A and component B (preferably in a volume ratio of 0.8:1 to 1.2:1, more preferably 1:1) has an elongation at break of 100% or more after curing for 7 days at 23°C and 50% RH when measured according to DIN EN ISO 527-2 and pulling the sample at 50 mm / min.
[0256] Examples
[0257]
[0258]
[0259] Preparation of adhesives
[0260] Component A (isocyanate)
[0261] Prepolymer preparation
[0262] The prepolymer was prepared in a 2 1 four-necked flask equipped with a mechanical stirring rod and a thermometer. The isocyanate-terminated prepolymer was prepared by first mixing the polyol components of component A and stirring at 120°C for 1 hour under reduced pressure. The polyol was cooled to 80°C, the isocyanate component was added, and the mixture was reacted at 80°C for 2 hours under reduced pressure. The material was then cooled to below 30°C. The vacuum was broken under nitrogen and the prepolymer was stored sealed until use.
[0263] A specific description of the prepolymer process is provided for Example 6 of the present invention. At room temperature, 568 g of NJ-330 was added to a four-necked flask equipped with a mechanical stirring rod and a thermometer. NJ-300 was dried at 120° C. for 1 hour under reduced pressure. The NJ-300 was cooled to 80° C., 712 g of MDI-50 was added to the flask, and the mixture was reacted at 80° C. for 2 hours under reduced pressure. 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 prepolymer that was mainly NCO-terminated.
[0264] To prepare component A, talc and fumed silica were dried in an oven at 120°C for 24 hours or more, using the amounts listed in Table 2, until the moisture content was less than 300 ppm. The prepolymer was added to a 2 1 planetary mixer and mixed together for 10 minutes. The dried talc and silica were added and stirring was continued at room temperature for another 30 minutes. The vacuum was then broken under nitrogen and component A was packaged in a sealed box for storage until use.
[0265] A detailed description of the preparation of component A is provided for Example 6 of the present invention. Solid talc and CAB-O-SIL TS-720 are dried in a 120° C. oven for at least 24 hours until the moisture content is less than 300 ppm. 640 g of prepolymer, 345 g of talc and 15 g of CAB-O-SIL are added to a 21 planetary mixer, having a red color. After mixing at room temperature for 30 minutes, the vacuum is broken with nitrogen, and the adhesive component can be filled in a suitable packaging size.
[0266] Component B (polyol)
[0267] To prepare component B (polyol), talc and CAB-O-SIL TS-720 were dried in an oven at 120°C for 24 hours or more, using the amounts listed in Table 2, until the moisture content was less than 300 ppm. Molecular sieves were used to dry the polyol 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 in a sealed box until use.
[0268] Store component A and component B separately until use. Just before use, mix the components in a 1:1 volume ratio and perform the following test.
[0269] Working hours
[0270] The working time is the time for the rheological viscosity to reach 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 simultaneously. The results are listed in Table 2.
[0271] Rheological viscosity
[0272] Rheological viscosity was measured 60 minutes after mixing Part A and Part B using a TA Rheometer with 25 mm parallel plates and 0.2 mm gap.
[0273] The results are listed in Table 2.
[0274] Lap shear strength
[0275] Lap shear strength is measured using DIN EN 1465, with a bond area of 250 mm 2 (10X 25mm), adhesive layer thickness was 1mm, and electro-coated steel was used for both substrates. All surfaces were prepared by cleaning with isopropyl alcohol before applying the adhesive. The curing conditions were 7 days at 23°C and 50% RH. During the test, the shear samples were stretched at 5mm / min. The results are listed in Table 2.
[0276] Tensile properties
[0277] Tensile strength, elastic modulus and elongation were measured according to DIN EN ISO 527-2; curing conditions: 7 days at 23° C., 50% RH; during the test, the tensile specimen was pulled at 50 mm / min. The results are listed in Table 2.
[0278]
[0279]
[0280] result
[0281] Inventive Example 6 showed a working time of more than 60 minutes, whereas the comparative example showed a working time of less than 60 minutes.
[0282] Inventive Example 6 showed a slower viscosity increase than the comparative example.
[0283] Inventive Example 6 exhibits greater elasticity (lower elastic modulus, higher elongation at break) than the comparative example.
Claims
1. A two-component thermally conductive polyurethane adhesive comprising: (A) Component A: (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A; (B) Component B: (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
2. A method for bonding two or more substrates, the method The following steps are involved: (1) Providing an adhesive, the adhesive comprising: (A) Component A: (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A; (B) Component B: (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and (bii) optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups; (2) mixing component A and component B to produce an adhesive mixture; (3) applying the adhesive mixture to a first substrate; (4) bringing the first substrate into bonding contact with the second substrate; (5) Curing the adhesive mixture.
3. A bonded assembly, wherein include: (1) a first substrate; (2) a second substrate bonded to the first substrate; The first substrate and the second substrate are bonded to each other by an adhesive prepared by mixing the following component A and component B together: (A) Component A: (ai) an NCO-terminated prepolymer, wherein the NCO-terminated prepolymer is obtained by n ) is prepared by reacting at least one polyol having a Da of greater than 2,000 and an OH functionality of 2 to 3 with 30 to 45 wt % of at least one polyisocyanate selected from aliphatic polyisocyanates and a mixture of 2,4'-methylene-bis(phenylisocyanate) (MDI) and 4,4'-MDI, based on the total weight of component A; (B) Component B: (bi) molecular weight (M n ) at least one polyol of less than 1,000 Da and an OH functionality of at least 2; and (bii) Optionally a catalyst capable of catalyzing the reaction of OH groups with NCO groups.
4. As claimed in any preceding claim, in, The polyol used to prepare the prepolymer is selected from polyether polyols, especially poly(C 2-4 -alkylene oxide) polyols.
5. As claimed in any preceding claim, in, The polyol used to make the prepolymer is selected from poly(propylene oxide) polyols.
6. As claimed in any preceding claim, in, The polyol used to make the prepolymer has a functionality of 2.5-3, more preferably 3.
7. As claimed in any preceding claim, in, The polyol used to make the prepolymer is a polyether polyol having a functionality of 2.5-3, more preferably 3.
8. As claimed in any preceding claim, in, The polyol used to make the prepolymer is a poly(propylene oxide) polyol having a functionality of 2.5-3, more preferably 3.
9. As claimed in any preceding claim, in, The polyol used to make the prepolymer has a molecular weight (M) greater than 2,500 Da. n ), more preferably it has a molecular weight (M) of 3,000 Da. n ).
10. As claimed in any preceding claim, in, The polyisocyanate is a mixture of 2,4'-MDI and 4,4'-MDI.
11. As claimed in any preceding claim, in, 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 0.667-1.5, more particularly preferably 0.8-1.5, even more particularly preferably 1-1.
5.
12. As claimed in any preceding claim, in, The at least one polyol is used in component A in an amount of 10-40 wt %, based on the total weight of component A, more preferably 25-35 wt %, particularly preferably 28-29 wt %.
13. As claimed in any preceding claim, in, The at least one polyisocyanate is used in component A in an amount of 20 to 50 wt %, based on the total weight of component A, more preferably 30 to 40 wt %, very particularly preferably 34 to 36 wt %.
14. As claimed in any preceding claim, in, The at least one polyol in component B comprises a polyol having a molecular weight (Mn) greater than 400 Da.
15. As claimed in any preceding claim, in, The at least one polyol in Component B comprises a polyol having a molecular weight (Mn) of 400-1,000 Da, more preferably 500-1,000 Da.
16. As claimed in any preceding claim, in, The at least one polyol in component B includes a polyol having a functionality of 3 or more.
17. As claimed in any preceding claim, in, The at least one polyol in component B comprises a polyol mixture, in particular a mixture of a polyol having a functionality of 3 and a polyol having a functionality of greater than 3.
18. As claimed in any preceding claim, in, The at least one polyol in component B comprises a triol selected from the group consisting of poly(C 2-4 -alkylene oxide) triols, in particular triols based on poly(propylene oxide), or castor oil.
19. As claimed in any preceding claim, in, 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 greater than 3, more preferably greater than 4, particularly preferably greater than 5, and castor oil.