High temperature resistant polyurethane adhesive and preparation method thereof

Abstract

The application relates to the field of C09J175 / 04, in particular to a high-temperature-resistant polyurethane adhesive and a preparation method thereof, which comprises a main agent and a curing agent, and the main agent preparation raw materials at least comprise 45-60 parts of polymeric polyol, 2-5 parts of aromatic diol chain extender, 1-6 parts of oxazolidine compound, 25-40 parts of filler and 8-15 parts of auxiliary agent, through adoption of specific polymeric polyol, cooperation of the aromatic diol chain extender and existence of other raw materials, the provided high-temperature-resistant polyurethane adhesive has excellent high-temperature resistance, the bonding performance and the bonding strength of the polyurethane adhesive are ensured, and the problems of foaming, hollowing and degumming caused by high water content of the base material are effectively solved.

Description

TECHNICAL FIELD

[0001] The application relates to the field of C09J175 / 04, in particular to a high-temperature-resistant polyurethane adhesive and a preparation method thereof. BACKGROUND

[0002] The sandwich material in the fireproof door is usually cement mortar and honeycomb board. The honeycomb board includes paper honeycomb board and aluminum honeycomb board. After the fireproof door is completed, baking varnish is needed in the baking room. During baking varnish, heating to 220 DEG C is needed for 20-30 min. During the baking varnish process, the bonding material cannot be delaminated and cannot be brittle. The adhesive needs to bond the galvanized sheet and the sandwich material, especially when the sandwich material of the fireproof door is the paper honeycomb board, it is more difficult to bond with the galvanized sheet. The paper honeycomb board has moisture, and after baking varnish, it will be brittle. The moisture content of the paper honeycomb board is generally 8-12%. When the moisture content of the base material is high, the adhesive will foam, resulting in hollowing and delamination. Therefore, providing a high-temperature-resistant polyurethane adhesive, and simultaneously solving the problems existing in the application of the existing polyurethane adhesive to the bonding of the sandwich material of the fireproof door core board is an important direction of the research in the field of polyurethane adhesives.

[0003] Chinese patent CN 109628051 B discloses a high-temperature-resistant three-component polyurethane adhesive and a preparation method thereof. The high-temperature-resistant polyurethane adhesive is prepared by using high-temperature-resistant aliphatic polyester polyol and aliphatic diisocyanate under the condition of high-temperature-resistant additives, but cannot resist 220 DEG C high temperature without delamination and brittleness in actual application to fireproof door baking. Chinese patent CN CN105085858B discloses a preparation method of a biologically modified high-temperature-resistant polyurethane adhesive. The polyurethane adhesive has good adhesion at 200-250 DEG C by introducing treated wheat straw particles and cellulase into the polyurethane system, but the adhesive system cannot effectively solve the problems of foaming, hollowing and delamination caused by high moisture content of the base material.

[0004] Therefore, the application provides a high-temperature-resistant polyurethane adhesive. By using specific polymer polyol and aromatic diol chain extender, the high-temperature-resistant polyurethane adhesive has excellent high-temperature resistance under the condition of other raw materials, ensures the bonding performance and bonding strength of the polyurethane adhesive, and effectively solves the problems of foaming, hollowing and delamination caused by high moisture content of the base material. SUMMARY

[0005] In one aspect, the application provides a high-temperature-resistant polyurethane adhesive, which comprises a main agent and a curing agent. The main agent is prepared from at least the following raw materials in parts by weight: polymer polyol 45-60 parts, aromatic diol chain extender 2-5 parts, oxazolidine compound 1-6 parts, filler 25-40 parts and additive 8-15 parts.

[0006] As a preferred technical solution, the polymer polyol is selected from at least one of polyester polyol, polyether polyol, vegetable oil polyol and polyolefin polyol; preferably, the polymer polyol is a mixture of polyester polyol and vegetable oil polyol, and the mass ratio of the polyester polyol to the vegetable oil polyol is (6-10):(1-3);

[0007] As a preferred technical solution, the vegetable oil polyol is a trifunctional castor oil modified polyol with a hydroxyl value of 160-188 mgKOH / g.

[0008] The trifunctional castor oil modified polyol is a URIC F-135 product purchased from Beijing Sanchangtaihe Science and Technology Co., Ltd.

[0009] Based on the system of the present application, the polyester polyol and the vegetable oil polyol are used in a mass ratio of (6-10):(1-3), and in particular, the vegetable oil polyol is a trifunctional castor oil modified polyol with a hydroxyl value of 160-188 mgKOH / g. The active hydrogen in the functional groups of the polyester polyol and the trifunctional castor oil modified polyol reacts with isocyanate (-NCO) to form a polyurethane adhesive with a large number of repeating urethane group (-NHCOO-) fragments. The polyurethane adhesive can produce strong chemical bond and hydrogen bond with the active hydrogen in the structure of the honeycomb panel material, so that the bonding between the interfaces is more reliable and durable. Under this mass ratio, the introduction of the trifunctional castor oil modified polyol can form a microporous structure during the curing reaction, so as to expand the volume of the polyurethane adhesive, increase the bonding area, reduce the cost, and improve the interfacial bonding strength. However, when the content of the trifunctional castor oil modified polyol is too high, it may affect the interfacial bonding performance of the polyurethane adhesive.

[0010] As a preferred technical solution, the polyester polyol is a phthalic anhydride polyester polyol; preferably, the phthalic anhydride polyester polyol is selected from one or a combination of diethylene glycol-based phthalic anhydride polyester polyol, neopentyl glycol-based phthalic anhydride polyester polyol, 1,6-hexanediol-based phthalic anhydride polyester polyol, modified diethylene glycol-based phthalic anhydride polyester polyol, and diethylene glycol phthalic anhydride polyester polyol; preferably, the viscosity (25℃) of the phthalic anhydride polyester polyol is 1500-4300 mPa·s; preferably, the viscosity (25℃) of the phthalic anhydride polyester polyol is 2300-4300 mPa·s.

[0011] The phthalic anhydride polyester polyol is a modified diethylene glycol-based phthalic anhydride polyester polyol with a model number of BC-180 purchased from Su Telin (Nanjing) New Material Technology Co., Ltd. BC-180, purchased from Su Telin (Nanjing) New Material Technology Co., Ltd.

[0012] From the exploration and research of the thermal degradation mechanism of polyurethane materials, it can be found that the traditional polyurethane materials have poor high temperature resistance, and the mechanical properties gradually decrease when used at about 100 DEG C for a long time, when the temperature continues to rise, the hard segment, side group and end group in the polymer chain begin to pyrolyze, then the soft segment begins to pyrolyze, and finally the polymer chain segment completely depolymerizes into small molecules and gas; the polyurethane adhesive is improved in high temperature resistance and mechanical properties by introducing rigid structure into the polyurethane adhesive structure by using phthalic anhydride polyester polyol, the rigidity of the polymer chain is enhanced, and the polyurethane adhesive is improved in high temperature resistance and mechanical properties; the inventor finds that the polyurethane adhesive has the best high temperature resistance when the viscosity (25 DEG C) of the phthalic anhydride polyester polyol in the system is 2300-4300 mPa s, especially when the phthalic anhydride polyester polyol is modified diethylene glycol-based phthalic anhydride polyester polyol, which may be due to that the modified diethylene glycol-based phthalic anhydride polyester polyol has high molecular structure regularity, good symmetry, high viscosity, increased molecular weight, increased crosslinking density of the polyurethane, and further improved heat resistance of the polyurethane adhesive.

[0013] As a preferred technical solution, the oxazolidine compound is one or a combination of E1, E2, E3 and E4; the structures of E1, E2, E3 and E4 are as follows:

[0014]

[0015] Preferably, the oxazolidine compound is E3, and the structure is

[0016] As a preferred technical solution, the filler at least includes organic silicon microsphere powder, silicon powder and 3A molecular sieve; preferably, the mass ratio of the organic silicon microsphere powder, the silicon powder and the 3A molecular sieve is (0.8-3):(18-25):(5-10).

[0017] Preferably, the average particle size of the organic silicon microsphere powder is 0.8-5 mu m; preferably, the particle size of the silicon powder is 2-4 mu m; preferably, the particle size of the 3A molecular sieve is 2-4 mu m.

[0018] The model of the organic silicon microsphere powder is YGF-102, which is purchased from Jiujiang Youmei New Material Technology Co., Ltd.; the silicon powder is purchased from Guangzhou Xinxili Metallurgical Chemical Co., Ltd.; and the 3A molecular sieve is purchased from Jiangxi Xintao Technology Co., Ltd.

[0019] Based on the system of the present application, by introducing oxazolidine compounds containing rigid heterocyclic structures, especially when the oxazolidine compound is E3, the thermal stability of the polyurethane adhesive is further improved by the organic silicon microsphere powder in the synergistic system, avoiding the adhesive falling off and brittle failure due to the too high baking temperature in the actual application process, and under the joint action of the silicon powder and 3A molecular sieve in the system, the reaction of isocyanate curing agent and water is inhibited, the foaming, hollowing and delamination problems of the polyurethane adhesive caused by the high water content of the substrate are solved, so that the provided polyurethane adhesive meets the bonding requirements of the honeycomb plate in the fire door core plate.

[0020] As a preferred technical solution, the aromatic diol chain extender is hydroquinone dihydroxyethyl ether and / or resorcinol bis-hydroxyethyl ether. Preferably, the aromatic diol chain extender is a mixture of hydroquinone dihydroxyethyl ether and resorcinol bis-hydroxyethyl ether, and the mass ratio of the hydroquinone dihydroxyethyl ether and the resorcinol bis-hydroxyethyl ether is (2-4):(4-6). Through thermal degradation analysis of polyurethane, it is found that the energy required for side chain and chain segment rupture of the polyurethane adhesive prepared by using traditional aliphatic diols is much lower than that required for polyurethane high molecular chain segment bond rupture, so the initial decomposition stage of polyurethane structure thermal decomposition is the degradation of side chains and chain segments. Based on the system of the present application, aromatic diol chain extenders are used, especially symmetric hydroquinone dihydroxyethyl ether, which has good compatibility with diphenylmethane diisocyanate, ensuring the curing effect, introducing rigid structural units into the molecular chain of the polyurethane adhesive, and improving the high temperature resistance of the polyurethane adhesive. However, the inventors found in actual production and processing that the melting point of hydroquinone dihydroxyethyl ether is relatively high, which needs to be heated to above 110 DEG C, and the operability is not good. By introducing resorcinol bis-hydroxyethyl ether, especially controlling the mass ratio of hydroquinone dihydroxyethyl ether and resorcinol bis-hydroxyethyl ether to be (2-4):(4-6), the processing operation temperature is effectively reduced, the effective operation time (pot life) is prolonged, and the processing and production of the polyurethane adhesive are facilitated.

[0021] The hydroquinone dihydroxyethyl ether and the resorcinol bis-hydroxyethyl ether are purchased from Zhangjiagang Yaru Chemical Co., Ltd.

[0022] As a preferred technical solution, the functional additives at least include a crosslinking agent, an adhesion promoter, a plasticizer, and a dispersant. Preferably, the mass ratio of the crosslinking agent, the adhesion promoter, the plasticizer, and the dispersant is (1-2):(2-4):(3-6):(1-3).

[0023] Preferably, the crosslinking agent is 2,4-diamino-3,5-dimethylthiochlorobenzene.

[0024] Preferably, the adhesion promoter is phenylmethylmethoxydimethylsilane.

[0025] Preferably, the plasticizer is triethylene glycol dimethyl ether.

[0026] Preferably, the dispersing agent is Coadis BR85, purchased from Shanghai Kaijin Chemical Co., Ltd.

[0027] Another aspect of the present application provides a preparation method of a high-temperature-resistant polyurethane adhesive, wherein, according to weight parts, polymer polyol, aromatic diol chain extender, oxazolidine compound, filler and auxiliary agent are stirred and mixed at 80-90 DEG C for 15-30 min, and then vacuum dehydration is performed to obtain a main agent; the main agent is mixed with a curing agent at a mass ratio of (80-100):(15-30), and then evenly mixed to obtain the high-temperature-resistant polyurethane adhesive.

[0028] As a preferred technical solution, the curing agent is an isocyanate curing agent; preferably, the isocyanate curing agent is diphenylmethane diisocyanate or polymethylene polyphenyl polyisocyanate.

[0029] Advantages

[0030] 1. The present application provides a high-temperature-resistant polyurethane adhesive, which has excellent high-temperature resistance by using specific polymer polyol and aromatic diol chain extender in the presence of other raw materials, thereby effectively solving the problems of foaming, hollowing and delamination caused by high water content of the substrate while ensuring the bonding performance and bonding strength of the polyurethane adhesive.

[0031] 2. According to the system of the present application, the polyester polyol and the vegetable oil polyol are used at a mass ratio of (6-10):(1-3), and especially when the vegetable oil polyol used is a trifunctional castor oil modified polyol with a hydroxyl value of 160-188 mgKOH / g, the prepared polyurethane adhesive can produce strong chemical bond and hydrogen bond with the active hydrogen in the structure of the honeycomb panel material, so that the interfacial bonding is more reliable and durable.

[0032] 3. By using phthalic anhydride polyester polyol, the present application introduces rigid structure into the structure of the polyurethane adhesive, enhances the rigidity of the polymer chain, and significantly improves the high-temperature resistance and mechanical properties of the polyurethane adhesive.

[0033] 4. By introducing oxazolidine compound containing rigid heterocyclic structure, especially when the oxazolidine compound is E3, and the organic silicon microsphere powder in the synergistic system, the thermal stability of the polyurethane adhesive is further improved, the problems of adhesive falling off and brittleness failure caused by too high baking temperature in actual application are avoided, and under the joint action of the silicon powder and 3A molecular sieve in the system, the reaction of isocyanate curing agent and water is inhibited, and the problems of foaming, hollowing and delamination of the polyurethane adhesive caused by high water content of the substrate are solved.

[0034] 5、Based on the system of the application, aromatic diol chain extender is used, especially symmetrical hydroquinone dihydroxyethyl ether, which has good compatibility with diphenylmethane diisocyanate, ensures the curing effect, introduces rigid structural units into the molecular chain of the polyurethane adhesive, and improves the high temperature resistance of the polyurethane adhesive. DETAILED DESCRIPTION

[0035] Embodiment 1

[0036] The embodiment 1 of the application provides a high-temperature-resistant polyurethane adhesive, which comprises a main agent and a curing agent, and the mass ratio of the main agent and the curing agent is 100:20; the preparation raw materials of the main agent include 55 parts of polymer polyol, 4 parts of aromatic diol chain extender, 3 parts of oxazolidine compound, 30 parts of filler and 12 parts of auxiliary agent.

[0037] The polymer polyol is a mixture of polyester polyol and vegetable oil polyol, and the mass ratio of the polyester polyol and the vegetable oil polyol is 8:2.

[0038] The vegetable oil polyol is a trifunctional castor oil modified polyol with a hydroxyl value of 160 mgKOH / g.

[0039] The trifunctional castor oil modified polyol is a URIC F-135 model purchased from Beijing Sanchangtai Science and Technology Co., Ltd.

[0040] The polyester polyol is phthalic anhydride polyester polyol; the phthalic anhydride polyester polyol is a modified diethylene glycol-based phthalic anhydride polyester polyol with a model of BC-180 purchased from Su Telin (Nanjing) New Material Technology Co., Ltd.

[0041] The oxazolidine compound is E3, and the structure is

[0042] The filler includes organic silicon microsphere powder, silicon powder and 3A molecular sieve; the mass ratio of the organic silicon microsphere powder, the silicon powder and the 3A molecular sieve is 2:20:8.

[0043] The average particle size of the organic silicon microsphere powder is 2 μm; the average particle size of the silicon powder is 2-4 μm; and the average particle size of the 3A molecular sieve is 3 μm.

[0044] The organic silicon microsphere powder is a YGF-102 model purchased from Jiujiang Youmei New Material Technology Co., Ltd.; the silicon powder is purchased from Guangzhou Xinxili Metallurgical Chemical Co., Ltd.; and the 3A molecular sieve is purchased from Jiangxi Xintao Technology Co., Ltd.

[0045] ​The aromatic diol chain extender is a mixture of hydroxyethyl p-hydroquinone ether and hydroxyethyl m-hydroquinone ether, and the mass ratio of the hydroxyethyl p-hydroquinone ether and the hydroxyethyl m-hydroquinone ether is 3:5.

[0046] The hydroxyethyl p-hydroquinone ether and the hydroxyethyl m-hydroquinone ether are both purchased from Zhangjiagang Yaru Chemical Co., Ltd.

[0047] The functional additives include a crosslinking agent, an adhesion promoter, a plasticizer, and a dispersant, and the mass ratio of the crosslinking agent, the adhesion promoter, the plasticizer, and the dispersant is 1.5:3.5:5:2.

[0048] The crosslinking agent is 2,4-diamino-3,5-dimethylthiochlorobenzene.

[0049] The adhesion promoter is benzyl methoxy dimethyl silane.

[0050] The plasticizer is triethylene glycol dimethyl ether.

[0051] The dispersant is Coadis BR85, which is purchased from Shanghai Kaijin Chemical Co., Ltd.

[0052] In another aspect, the embodiment 1 of the present application provides a preparation method of a high-temperature-resistant polyurethane adhesive, wherein polymer polyol, aromatic diol chain extender, oxazolidine compound, filler, and additive are stirred and mixed at 90 DEG C for 20 minutes, and then vacuum dehydration is performed to obtain a main agent; the main agent and a curing agent are uniformly mixed according to the mass ratio of (80-100):(15-30), and the high-temperature-resistant polyurethane adhesive is obtained.

[0053] The curing agent is an isocyanate curing agent, and the isocyanate curing agent is diphenylmethane diisocyanate.

[0054] Embodiment 2

[0055] In one aspect, the embodiment 2 of the present application provides a high-temperature-resistant polyurethane adhesive, which comprises a main agent and a curing agent, and the mass ratio of the main agent and the curing agent is 100:20; the preparation raw materials of the main agent include, by weight, 60 parts of polymer polyol, 5 parts of aromatic diol chain extender, 5 parts of oxazolidine compound, 35 parts of filler, and 15 parts of additive.

[0056] The polymer polyol is a mixture of polyester polyol and vegetable oil polyol, and the mass ratio of the polyester polyol and the vegetable oil polyol is 10:3.

[0057] The vegetable oil polyol is trifunctional castor oil modified polyol with a hydroxyl value of 160 mgKOH / g.

[0058] The tri-functionality castor oil modified polyol is model URIC F-135, purchased from Beijing Sanchangtai Science and Technology Co., Ltd.

[0059] The polyester polyol is a phthalic anhydride polyester polyol; the phthalic anhydride polyester polyol is a modified diethylene glycol-based phthalic anhydride polyester polyol, model BC-180, purchased from Su Telin (Nanjing) New Material Technology Co., Ltd.

[0060] The oxazolidine compound is E3, and the structure is

[0061] The filler includes organic silicon microsphere powder, silicon micro powder and 3A molecular sieve; the mass ratio of the organic silicon microsphere powder, the silicon micro powder and the 3A molecular sieve is 3:22:10.

[0062] The average particle size of the organic silicon microsphere powder is 2 μm; the average particle size of the silicon micro powder is 2-4 μm; the average particle size of the 3A molecular sieve is 3 μm;

[0063] The organic silicon microsphere powder is model YGF-102, purchased from Jiujiang Youmei New Material Technology Co., Ltd.; the silicon micro powder is purchased from Guangzhou Xinxili Metallurgical Chemical Co., Ltd.; and the 3A molecular sieve is purchased from Jiangxi Xintao Technology Co., Ltd.

[0064] The aromatic diol chain extender is a mixture of hydroquinone dihydroxyethyl ether and resorcinol bis-hydroxyethyl ether, and the mass ratio of the hydroquinone dihydroxyethyl ether and the resorcinol bis-hydroxyethyl ether is 4:6.

[0065] Both the hydroquinone dihydroxyethyl ether and the resorcinol bis-hydroxyethyl ether are purchased from Zhangjiagang Yaru Chemical Co., Ltd.

[0066] The functional auxiliary agent includes a crosslinking agent, an adhesion promoter, a plasticizer and a dispersant; the mass ratio of the crosslinking agent, the adhesion promoter, the plasticizer and the dispersant is 2:4:6:3.

[0067] The crosslinking agent is 2,4-diamino-3,5-dimethylthiochlorobenzene;

[0068] The adhesion promoter is phenylmethylmethoxydimethylsilane;

[0069] The plasticizer is triethylene glycol dimethyl ether;

[0070] The dispersant is Coadis BR85, purchased from Shanghai Kaijin Chemical Co., Ltd.

[0071] The embodiment 2 of the present application provides a preparation method of the high-temperature-resistant polyurethane adhesive, and the preparation method comprises the following steps: mixing polymer polyol, aromatic diol chain extender, oxazolidine compound, filler and auxiliary agent at 90 DEG C and stirring for 20 min, and then performing vacuum dehydration to obtain the high-temperature-resistant polyurethane adhesive.

[0072] The use method of the high-temperature-resistant polyurethane adhesive comprises the following steps: mixing the main agent and the curing agent uniformly according to the mass ratio of 100:20 to obtain the high-temperature-resistant polyurethane adhesive.

[0073] Embodiment 3

[0074] The embodiment 3 of the present application provides a high-temperature-resistant polyurethane adhesive, which comprises a main agent and a curing agent, and the mass ratio of the main agent and the curing agent is 100:20; the preparation raw material of the main agent comprises the following components in parts by weight: 50 parts of polymer polyol, 3 parts of aromatic diol chain extender, 2 parts of oxazolidine compound, 25 parts of filler and 10 parts of auxiliary agent.

[0075] The polymer polyol is a mixture of polyester polyol and vegetable oil polyol, and the mass ratio of the polyester polyol and the vegetable oil polyol is 6:1.

[0076] The vegetable oil polyol is trifunctional castor oil modified polyol with a hydroxyl value of 160 mgKOH / g.

[0077] The trifunctional castor oil modified polyol is URIC F-135, which is purchased from Beijing Sanchangtai Science and Technology Co., Ltd.

[0078] The polyester polyol is phthalic anhydride polyester polyol; the phthalic anhydride polyester polyol is modified diethylene glycol-based phthalic anhydride polyester polyol, and the model number is BC-180, which is purchased from Su Telin (Nanjing) New Material Technology Co., Ltd.

[0079] The oxazolidine compound is E3, and the structure is as follows:

[0080] The filler comprises organic silicon microsphere powder, silicon powder and 3A molecular sieve, and the mass ratio of the organic silicon microsphere powder, the silicon powder and the 3A molecular sieve is 2:15:8.

[0081] The average particle size of the organic silicon microsphere powder is 2 mu m; the average particle size of the silicon powder is 2-4 mu m; and the average particle size of the 3A molecular sieve is 3 mu m.

[0082] ​The model of the organic silicone microsphere powder is YGF-102, which is purchased from Jiujiang Youmei New Material Technology Co., Ltd.; the silicon micro powder is purchased from Guangzhou Xinxili Metallurgical Chemical Co., Ltd.; and the 3A molecular sieve is purchased from Jiangxi Xintao Science and Technology Co., Ltd.

[0083] The aromatic diol chain extender is a mixture of hydroquinone dihydroxyethyl ether and resorcinol bis-hydroxyethyl ether, and the mass ratio of the hydroquinone dihydroxyethyl ether and the resorcinol bis-hydroxyethyl ether is 2:4.

[0084] Both the hydroquinone dihydroxyethyl ether and the resorcinol bis-hydroxyethyl ether are purchased from Zhangjiagang Yaru Chemical Co., Ltd.

[0085] The functional aids include a crosslinking agent, an adhesion promoter, a plasticizer and a dispersant, and the mass ratio of the crosslinking agent, the adhesion promoter, the plasticizer and the dispersant is 1:3:5:1.

[0086] The crosslinking agent is 2,4-diamino-3,5-dimethylthiochlorobenzene.

[0087] The adhesion promoter is phenylmethylmethoxydimethylsilane.

[0088] The plasticizer is triethylene glycol dimethyl ether.

[0089] The dispersant is Coadis BR85, which is purchased from Shanghai Kaixin Chemical Co., Ltd.

[0090] In another aspect, the embodiment 3 of the present application provides a preparation method of the high-temperature-resistant polyurethane adhesive. The polymer polyol, the aromatic diol chain extender, the oxazolidine compound, the filler and the aid are stirred and mixed at 90 DEG C for 20 min, and then vacuum dehydration is performed to obtain a main agent. The main agent and a curing agent are uniformly mixed according to the mass ratio of (80-100):(15-30), and the high-temperature-resistant polyurethane adhesive is obtained.

[0091] The curing agent is an isocyanate curing agent, and the isocyanate curing agent is diphenylmethane diisocyanate.

[0092] Comparative example 1

[0093] The comparative example 1 of the present application provides a high-temperature-resistant polyurethane adhesive, and the specific implementation manner is the same as that of the embodiment 1, and the difference lies in that the mass ratio of the polyester polyol and the vegetable oil polyol is 6:4.

[0094] Comparative example 2

[0095] The comparative example 2 of the present application provides a high-temperature-resistant polyurethane adhesive, and the specific implementation manner is the same as that of the embodiment 1, and the difference lies in that the oxazolidine compound is E2, and the structure is

[0096] Comparative Example 3

[0097] Comparative Example 3 of the present application provides a high-temperature resistant polyurethane adhesive, the specific implementation of which is the same as that of Example 1, except that the aromatic diol chain extender in the raw materials for preparing the high-temperature resistant polyurethane adhesive is replaced by 1,4-butanediol.

[0098] Comparative Example 4

[0099] Comparative Example 4 of the present application provides a high-temperature resistant polyurethane adhesive, the specific implementation of which is the same as that of Example 1, except that the polyester polyol is polybutylene adipate.

[0100] Comparative Example 5

[0101] Comparative Example 5 of the present application provides a high-temperature resistant polyurethane adhesive, the specific implementation of which is the same as that of Example 1, except that the filler is silicon powder.

[0102] Performance test method

[0103] Aluminum alloy was used as the bonding test piece, the surface of the aluminum alloy was polished with 0# sandpaper, and the surface grease was removed by ultrasonic cleaning with acetone for 15 min. The surface was treated by FPL oxidation method, then washed with deionized water, and dried in a 60°C air drying oven before use.

[0104] 1. High-temperature resistance

[0105] The high-temperature resistant polyurethane adhesives obtained by the examples and comparative examples were coated on the surface of the above-mentioned treated aluminum alloy test piece, the temperature was controlled at 225°C, and high-temperature baking was carried out for 30 min. After taking out and drying to room temperature, if the adhesive layer did not appear brittle and fall off, it was recorded as "qualified", if the adhesive layer appeared brittle and fell off, it was recorded as "unqualified", and the results are shown in Table 1.

[0106] 2. Tensile shear strength test

[0107] According to the method of GB / T 7124-2008, the tensile shear strength of the high-temperature resistant polyurethane adhesives obtained by the examples and comparative examples was tested, wherein the tensile shear strength of 6-7 MPa (including 6 MPa) was recorded as "excellent", the tensile shear strength of 5-6 MPa (including 6 MPa) was recorded as "good", and the tensile shear strength < 5 MPa was recorded as "poor", and the results are shown in Table 1.

[0108] 3. Adhesion performance test

[0109] According to the national standard "GB / T 5210-1985 Determination of Adhesion of Coating - Pull-Over Method", the high temperature resistant polyurethane adhesive prepared by the examples and the comparative examples was coated on the surface of the above treated aluminum alloy test piece, and after curing at 60°C, the adhesion of the adhesive coating was determined, and the results are shown in Table 1.

[0110] 4.180° peel strength test

[0111] According to the national standard "GB / T 2790-1985 Determination of Adhesion of Coating - Pull-Over Method", the high temperature resistant polyurethane adhesive prepared by the examples and the comparative examples was coated on the surface of the above treated aluminum alloy test piece, and after curing at 60°C, the adhesion of the adhesive coating was determined, and the results are shown in Table 1.

[0112]

Claims

1. A high-temperature resistant polyurethane adhesive, characterized in that, The main agent and curing agent are included. By weight, the main agent preparation raw materials include at least: 45-60 parts of polymeric polyol, 2-5 parts of aromatic diol chain extender, 1-6 parts of oxazolidine compound, 25-40 parts of filler, and 8-15 parts of additives; the polymeric polyol is a mixture of polyester polyol and vegetable oil polyol, with a mass ratio of (6-10):(1-3); the vegetable oil polyol is a trifunctional castor oil-modified polyol with a hydroxyl value of 160-188 mgKOH / g; the polyester polyol is a modified diethylene glycol phthalic anhydride polyester polyol with a viscosity of 2300-4300 mPa·s at 25°C; the oxazolidine compound is E3 with the following structure: The filler comprises at least organosilicon microspheres, silica powder, and 3A molecular sieve, wherein the mass ratio of organosilicon microspheres, silica powder, and 3A molecular sieve is (0.8-3):(18-25):(5-10), the average particle size of the organosilicon microspheres is 0.8-5 μm, the particle size of the silica powder is 2-4 μm, and the particle size of the 3A molecular sieve is 2-4 μm; the aromatic diol chain extender is a mixture of hydroquinone dihydroxyethyl ether and resorcinol dihydroxyethyl ether, wherein the mass ratio of hydroquinone dihydroxyethyl ether and resorcinol dihydroxyethyl ether is (2-4):(4-6).

2. The high-temperature resistant polyurethane adhesive according to claim 1, characterized in that, The additives include at least crosslinking agents, adhesion promoters, plasticizers, and dispersants.

3. The high-temperature resistant polyurethane adhesive according to claim 1, characterized in that, The curing agent is an isocyanate-based curing agent.

4. A method for preparing a high-temperature resistant polyurethane adhesive according to any one of claims 1-3, characterized in that, By weight, the polymer polyol, aromatic diol chain extender, oxazolidine compound, filler and additive are stirred and mixed at 80-90℃ for 15-30 minutes, and then vacuum dehydrated to obtain the main agent; the main agent and curing agent are mixed evenly according to the mass ratio of (80-100):(15-30) to obtain the final product.

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