High-temperature-resistant adhesive and product thereof

Abstract

The invention relates to the technical field of adhesives, in particular to a high-temperature-resistant adhesive and a product thereof. The high-temperature-resistant adhesive is prepared from the following components in parts by weight: 60 to 80 parts of epoxy resin, 10 to 20 parts of benzoxazine resin, 10 to 20 parts of thermoplastic polyurethane resin and 0.1 to 1 part of anhydride curing agent, wherein the total weight part of the epoxy resin, the benzoxazine resin and the thermoplastic polyurethane resin is 100 parts. The epoxy resin, the benzoxazine resin, the thermoplastic polyurethane resin and the anhydride curing agent are compounded, the cured adhesive can form a compact network structure, and the toughness of a cured adhesive film can be improved by introducing a proper amount of thermoplastic polyurethane resin; the adhesive with excellent balance among high temperature resistance, shear strength and impact strength is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, in particular to a high temperature resistant adhesive and a product thereof. Background Art

[0002] Heat-activated adhesives are adhesives that are bonded by heating to produce viscosity. The adhesive resin component is solid at room temperature. When the temperature reaches the activation temperature, it triggers the heat activation reaction of the resin, thereby achieving high-strength bonding with the surface of the object to be bonded. Adhesive resins are divided into stages A, B, C and D according to the degree of curing. The resin in stage A is liquid; stage B is a semi-cured state, that is, the original state is solid, and it turns into a fluid at high temperature. It has precise positioning and excellent adhesion, and is widely used in precision electronic products; while stages C and D are in a cured state and do not have a bonding effect.

[0003] The packaging of microelectronic devices, flip-chip in the optical communication industry, and bonding of electronic components in the current market generally use rubber pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, or polyurethane adhesives. However, the bonding process of these types of adhesives to metal substrates is relatively complicated, and the bonding performance to metal substrates is relatively poor and the impact strength is low; in addition, since these electronic components or electronic devices often encounter high temperature environments during operation, generally external high temperature environments, or high temperatures caused by the heat emitted by electronic products themselves when they work for a long time, high temperatures or sudden temperature changes will cause changes in the internal stress of the adhesive, which will lead to bonding cracks or decreased viscosity, thereby affecting the service life of the adherend.

[0004] B-stage adhesives have two-step curing, i.e. low-temperature pre-curing and high-temperature further curing, which can better control the viscosity and curing process of the adhesive and simplify the bonding process. However, the bonding performance of existing B-stage adhesives will rapidly decrease under long-term high-temperature conditions, which greatly limits the application of such products under high-temperature conditions. Therefore, it is of great significance to develop an adhesive with high-temperature resistance.

[0005] In view of this, the present invention particularly proposes a high temperature resistant adhesive. Summary of the invention

[0006] The invention provides a high temperature resistant adhesive which has excellent shear strength and impact strength both at room temperature and at high temperature and has good high temperature resistance.

[0007] In order to achieve the above-mentioned object of the present invention, the first aspect of the present invention provides a high temperature resistant adhesive, comprising the following components in parts by weight:

[0008]

[0009] Wherein, the total weight of the epoxy resin, the benzoxazine resin and the thermoplastic polyurethane resin is 100 parts.

[0010] Furthermore, the epoxy equivalent of the epoxy resin is 2,300 to 3,800 g / eq.

[0011] Furthermore, the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

[0012] Furthermore, the glass transition temperature (Tg) of the benzoxazine resin is greater than 170°C.

[0013] Furthermore, the benzoxazine resin includes at least one of bisphenol A type benzoxazine resin, bisphenol F type benzoxazine resin and diamine type benzoxazine resin.

[0014] Furthermore, the thermoplastic polyurethane resin is a heat-activated polyurethane resin. Furthermore, the curing time of the thermoplastic polyurethane resin is ≤ 5 minutes.

[0015] Furthermore, the weight average molecular weight of the thermoplastic polyurethane resin is ≥70,000 g / mol.

[0016] Furthermore, the acid value of the acid anhydride curing agent is 380-435 mgKOH / g.

[0017] The second aspect of the present invention provides an adhesive product, comprising a support layer and an adhesive layer disposed on at least one side of the support layer; the adhesive layer is mainly made of the high temperature resistant adhesive described in the first aspect of the present invention.

[0018] Furthermore, the thickness of the adhesive layer is 50-100 μm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention adopts a compound of epoxy resin, benzoxazine resin, thermoplastic polyurethane resin and anhydride curing agent. The adhesive can form a dense network structure after B-stage curing. In addition, due to the introduction of thermoplastic polyurethane resin, the toughness of the film after curing can be improved, so as to obtain an adhesive with excellent balance between high temperature resistance, shear strength and impact strength;

[0021] (2) The adhesive products made by using the adhesive of the present invention have excellent shear strength and impact strength at both room temperature and high temperature environments, and good high temperature resistance. DETAILED DESCRIPTION

[0022] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0023] The first aspect of the present invention provides a high temperature resistant adhesive, comprising the following components in parts by weight:

[0024]

[0025] Wherein, the total weight of the epoxy resin, the benzoxazine resin and the thermoplastic polyurethane resin is 100 parts.

[0026] The adhesive of the present invention adopts a compound of multiple components. In the B-stage hot pressing curing stage of the adhesive, under high temperature and hot pressing conditions, the anhydride curing agent opens the anhydride ring under heat to form a free carboxylic acid group, and the epoxy resin opens the epoxy group under heat to form a hydroxyl group, and the two react to form an ester bond; and the benzoxazine resin opens the ring to form a phenolic hydroxyl group after being heated, and the phenolic hydroxyl groups can self-polymerize into a three-dimensional cross-linked network structure, and also condense with a small amount of anhydride curing agent and epoxy resin to form a cross-linked network structure with an ester group or an ether structure; at the same time, these newly generated carboxylic acid groups can promote the opening of the benzoxazine resin and the epoxy resin, so as to form a dense cross-linked network structure, improve the modulus of the adhesive, and improve the high temperature resistance and mechanical properties of the adhesive. By introducing a thermoplastic polyurethane resin, it has good heat resistance and toughness, and the cured adhesive can have suitable toughness, avoiding the decrease in bonding performance caused by the adhesive being too hard after curing.

[0027] For example, in different embodiments, in the high temperature resistant adhesive, the amounts of each component in parts by weight may be as follows:

[0028] The amount of the epoxy resin can be 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 78 parts, 80 parts or any value between any two end values; regulating the amount of the epoxy resin within the above range not only ensures good bonding performance of the adhesive, but also can give the adhesive film suitable shear strength and impact strength after curing;

[0029] The amount of the benzoxazine resin can be 10 parts, 12 parts, 15 parts, 18 parts, 20 parts or any value between any two ends thereof; the amount of the benzoxazine resin is adjusted within the above range to ensure the high temperature resistance and mechanical properties of the adhesive;

[0030] The amount of the thermoplastic polyurethane resin can be 10 parts, 12 parts, 15 parts, 18 parts, 20 parts or any value between any two end values; by adjusting the amount of the thermoplastic polyurethane resin within the above range, the toughness, shear strength and bonding performance of the adhesive can be balanced to avoid the adhesive film being too hard after curing, resulting in a decrease in bonding performance;

[0031] Wherein, the total weight of the epoxy resin, the benzoxazine resin and the thermoplastic polyurethane resin is 100 parts;

[0032] The dosage of the acid anhydride curing agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, or 1 part; an appropriate amount of the acid anhydride curing agent combined with the other components can form a dense cross-linked network structure during the hot pressing stage, thereby improving the overall bonding performance of the adhesive.

[0033] In a specific embodiment of the present invention, the epoxy equivalent of the epoxy resin is not less than 2,300 g / eq and not more than 3,800 g / eq. The "epoxy equivalent" described in the present invention refers to the number of grams of epoxy resin containing one equivalent of epoxy groups. The higher the value, the lower the proportion of epoxy groups. The epoxy equivalent of the epoxy resin in the present invention is relatively high, indicating that its epoxy group proportion is relatively low, which can avoid excessive internal crosslinking of the adhesive and loss of bonding performance. The epoxy equivalent test method of the epoxy resin of the present invention is tested in accordance with the international standard ASTM D1652-11 "Standard Test Method for Epoxy Equivalent of Epoxy Resins".

[0034] In a specific embodiment of the present invention, the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin, preferably bisphenol A epoxy resin.

[0035] In a specific embodiment of the present invention, the Tg of the benzoxazine resin is greater than 170° C. The benzoxazine resin has a high Tg value, which can improve the high temperature resistance, shear strength and impact resistance of the adhesive. The Tg value of the benzoxazine resin in the present invention can be tested by differential scanning calorimetry (DSC).

[0036] In a specific embodiment of the present invention, the benzoxazine resin includes at least one of bisphenol A type benzoxazine resin, bisphenol F type benzoxazine resin and diamine type benzoxazine resin, preferably bisphenol A type benzoxazine resin.

[0037] In a specific embodiment of the present invention, the thermoplastic polyurethane resin is a heat-activated polyurethane resin. The curing time of the thermoplastic polyurethane resin is ≤5 minutes, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes and 5 minutes or any value in the range thereof. In the present invention, the heat-activated polyurethane resin refers to a resin that is solid at room temperature and can be made into a fluid state under heat activation conditions to achieve bonding. The curing time refers to the shortest time for a polyurethane resin to change from a solid state to a fluid state at a certain temperature. The present invention adopts a curing time within this time range to give the adhesive good bonding properties in the medium and low temperature (60-90°C) stage, and further cures in the high temperature (160-220°C) stage to improve the toughness, mechanical strength and bonding stability of the adhesive.

[0038] In a specific embodiment of the present invention, the weight average molecular weight of the thermoplastic polyurethane resin is not less than 70,000 g / mol. The molecular weight of the thermoplastic polyurethane resin is limited to a relatively high value, so as to give full play to its toughening effect and balance the strength of the adhesive.

[0039] In a specific embodiment of the present invention, the acid value of the anhydride curing agent is not less than 380 mg KOH / g and not more than 435 mg KOH / g. The "acid value" in the present invention refers to the number of milligrams of potassium hydroxide (KOH) required to neutralize 1 g of chemical substances. The higher the value, the stronger the acidity and the more free fatty acids it contains. The higher the acid value of the anhydride curing agent in the present invention, the higher the free fatty acid content, so that it can be cross-linked and cured with more benzoxazine resins, thereby improving the curing efficiency of the adhesive.

[0040] Furthermore, the acid anhydride curing agent includes at least one of monofunctional acid anhydride, difunctional acid anhydride and free acid anhydride. Among them, the monofunctional acid anhydride includes at least one of phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and dodecenyl succinic anhydride; the difunctional acid anhydride includes at least one of pyromellitic anhydride, benzophenone tetracarboxylic anhydride and methylcyclohexene tetracarboxylic anhydride; the free acid anhydride includes at least one of trimellitic anhydride and polyazelaic anhydride. Dodecenyl succinic anhydride is preferred in the present invention.

[0041] In a specific embodiment of the present invention, the high temperature resistant adhesive may further include a solvent, the main function of the solvent is to dilute the adhesive to facilitate coating, the amount of solvent added can be calculated according to the required solid content of the coating, and the coating solid content of the general adhesive can be controlled at 35% to 45%. Further, the solvent can be a conventional organic solvent, including but not limited to ethyl acetate.

[0042] In the present invention, there is no restriction on the preparation method of the high temperature resistant adhesive, and a conventional preparation method of the adhesive can be used. The present invention provides a preparation method of the high temperature resistant adhesive according to the first aspect of the present invention, comprising the following steps: mixing the components by weight, stirring evenly and standing to defoam, to obtain the adhesive to be coated.

[0043] In a specific embodiment of the present invention, the preparation method further comprises: uniformly mixing the components in parts by weight, and then adding a solvent to adjust the solid content to 35% to 45%, thereby obtaining the adhesive to be coated.

[0044] It is understandable that, in order to facilitate production, transportation and sales, the adhesive of the present invention only limits the composition of the components but not the form of the components, that is, the components can be mixed with each other or stored separately. The mixed or separate storage mode can be selected according to the actual use time.

[0045] The second aspect of the present invention provides an adhesive product, comprising a support layer and an adhesive layer disposed on at least one side of the support layer; the adhesive layer is mainly made of the high temperature resistant adhesive described in the first aspect above.

[0046] Furthermore, the thickness of the adhesive layer is 50-100 μm, for example, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or any value between the two ends. If the thickness of the adhesive layer in the present invention is too thick, it is difficult to fully solidify during hot pressing, and the bonding performance does not meet the requirements; if the thickness is too thin, the bonding strength of the adhesive will decrease.

[0047] In a specific embodiment of the present invention, the support layer can be a substrate, a release film or other structure that can support the adhesive layer. Generally, when used as a double-sided adhesive, the support layer uses a release film, and the release film can be a non-silicon release film.

[0048] The present invention also provides an optional preparation method of the above adhesive product, comprising the following steps: coating the adhesive on the surface of the support layer, and drying the adhesive to obtain the adhesive product.

[0049] The coating method is not limited, and conventional coating methods such as roller coating, blade coating or dip coating can be used. The thickness of the support layer can be freely selected according to actual needs, and there is no special limitation. For example, it can be set to 25 to 100 μm, and specifically can be 25 μm, 30 μm, 40 μm, 50 μm, 80 μm, 100 μm or any value between the two ends.

[0050] In a specific embodiment of the present invention, the drying process comprises: drying at 100 to 120° C. for 4 to 6

[0051] min.

[0052] In actual use, the adhesive product of the present invention can be pre-laminated on the surface of the object to be bonded and then heat-pressed; wherein the pre-lamination temperature is 80-90°C; during the heat-pressing treatment, the temperature is 180-200°C, the pressure is 0.5Mpa-1Mpa, and the heat-pressing time is 1-5 minutes.

[0053] The adhesive product of the present invention can be used for bonding metal substrates such as aluminum (Al) in actual use, but is not limited thereto. The thickness of the metal substrate is generally not more than 1 cm. If the thickness of the bonded substrate is thicker, it will affect the thermosetting effect and further affect the bonding performance of the adhesive.

[0054] The following specific examples are listed to further illustrate the objects and advantages of the present invention, but these examples should not be construed as limiting the present invention. In the following examples, 1 g represents 1 part by weight. The weight average molecular weight of the thermoplastic polyurethane resin in the following examples of the present invention is measured by gel permeation chromatography (GPC).

[0055] Example 1

[0056] This embodiment provides a high temperature resistant adhesive, the components of which are as follows:

[0057] Epoxy resin: EPON produced by Westlake Epoxy Inc. in the United States TM Resin 1009F (bisphenol A epoxy resin), with an epoxy equivalent of 2,300 to 3,800 g / eq, 70 g;

[0058] Benzoxazine resin: BZ2112 (bisphenol A type benzoxazine resin) produced by Puyang Enying Polymer Materials Co., Ltd., with Tg>190°C, 15g;

[0059] Thermoplastic polyurethane resin: L95090 produced by Asahikawa Chemical (Suzhou) Co., Ltd. was used, with a curing time of 5 minutes and a molecular weight of 160,000 g / mol, 15 g;

[0060] Anhydride curing agent: K12 (dodecenyl succinic anhydride) produced by Xunjie (Shanghai) New Materials Co., Ltd. is used, with an acid value of 395-432 mgKOH / g, 0.3 g;

[0061] The preparation method of the adhesive is as follows: the above components are mixed evenly, and a proper amount of ethyl acetate is added to dilute the mixture to a solid content of 40%, thereby obtaining the adhesive to be coated.

[0062] Example 2

[0063] This example is carried out with reference to Example 1, except that the amounts of the components in the adhesive are different, and the rest are the same as Example 1. The specific differences are as follows:

[0064] 60g EPON TM Resin 1009F, 20g of BZ2112, 20g of L95090 and 1g of K12.

[0065] Example 3

[0066] This example is carried out with reference to Example 1, except that the amounts of the components in the adhesive are different, and the rest are the same as Example 1. The specific differences are as follows:

[0067] 80g EPON TM Resin 1009F, 10g of BZ2112, 10g of L95090 and 0.1g of K12.

[0068] Example 4 Group

[0069] This embodiment group was carried out with reference to the embodiment 1, except that: benzoxazine resins with different Tg values ​​were used in the adhesive, and the rest were the same as the embodiment 1, and the specific differences are as follows:

[0070] Example 4a: The benzoxazine resin used is BZ2100 (bisphenol A type benzoxazine resin) produced by Puyang Enying Polymer Materials Co., Ltd., and its Tg is greater than 170° C.;

[0071] Example 4b: The benzoxazine resin used is CB7100 (diamine type benzoxazine resin) produced by Chengdu Keyi Polymer Technology Co., Ltd., and its Tg is greater than 210°C;

[0072] Example 4c: The benzoxazine resin is replaced by an equal weight of SQP40AXM40 (phenoxy resin) produced by Jinan Shengquan Group Co., Ltd., whose Tg = 84°C.

[0073] Example 5 Group

[0074] This embodiment group is carried out with reference to the embodiment 1, except that: the adhesive uses thermoplastic polyurethane resins with different heat curing times and weight average molecular weights, and the rest are the same as the embodiment 1, and the specific differences are as follows:

[0075] Example 5a: The thermoplastic polyurethane resin used is L95070 produced by Asahikawa Chemical (Suzhou) Co., Ltd., with a heat curing time of 3 minutes and a molecular weight of 70,000 g / mol;

[0076] Example 5b: The thermoplastic polyurethane resin used is L95130 produced by Asahikawa Chemical (Suzhou) Co., Ltd., with a heat curing time of 10 minutes and a molecular weight of 150,000 g / mol;

[0077] Example 5c: The thermoplastic polyurethane resin used is L95085H produced by Asahikawa Chemical (Suzhou) Co., Ltd., which has a heat curing time of 1 minute and a molecular weight of 54,000 g / mol.

[0078] Comparative Example 1

[0079] This comparative example group was carried out with reference to Example 1, except that the amounts of the components in the adhesive were different, and the rest were the same as Example 1. The specific differences are as follows.

[0080] Comparative Example 1a: 55g EPON TM Resin 1009F, 25g of BZ2112, 20g of L95090 and 1g of K12;

[0081] Comparative Example 1b: 85g EPON TM Resin 1009F, 5g of BZ2112, 10g of L95090 and 0.1g of K12;

[0082] Comparative Example 1c: 80g EPON TM Resin 1009F, without BZ2112, 20g of L95090 and 0.1g of K12.

[0083] Comparative Example 2

[0084] This comparative example group was carried out with reference to Example 1, except that the amounts of the components in the adhesive were different, and the rest were the same as Example 1. The specific differences are as follows.

[0085] Comparative Example 2a: 85g EPON TM Resin 1009F, 10g of BZ2112, 5g of L95090 and 0.1g of K12;

[0086] Comparative Example 2b: 55g EPON TM Resin 1009F, 20g of BZ2112, 25g of L95090 and 1g of K12;

[0087] Comparative Example 2c: 80g EPON TM Resin 1009F, 20g of BZ2112, no L95090, 1g of K12.

[0088] Comparative Example 3

[0089] This comparative example group was carried out with reference to Example 1, except that the amount or acid value of the anhydride curing agent in the adhesive was different, and the rest was the same as Example 1. The specific differences are as follows.

[0090] Comparative Example 3a: 0.05 g of K12;

[0091] Comparative Example 3b: 1.3 g of K12;

[0092] Comparative Example 3c: does not contain K12;

[0093] Comparative Example 3d: Using an equal mass of tung oil anhydride produced by Hubei Julongtang Pharmaceutical Chemical Co., Ltd., the acid value of which is 129-131 mgKOH / g;

[0094] Comparative Example 3e: An equal mass of JHY906 (methyltetrahydrophthalic anhydride) produced by Zhejiang Zhengda New Materials Technology Co., Ltd. was used, and its acid value was 660-685 mgKOH / g.

[0095] Test Case

[0096] The adhesives prepared in the above embodiments and comparative examples were coated on the surface of a 50 μm thick non-silicone release film by blade coating, and placed in an oven at 110°C for 5 minutes to form a 60 μm thick adhesive film; after the release film of a 2 cm × 3 cm adhesive film sample was removed, it was bonded between two layers of aluminum-based plates (the thickness of a single-layer aluminum plate substrate is 3 mm), preheated and bonded at 85°C, and then hot-pressed at 190°C and 0.5 MPa for 5 minutes, and then cooled to room temperature (25°C), and the following tests were performed. The test results are shown in Table 1.

[0097] Shear strength test: Place the hot-pressed sample in a standard environment (23±1℃, 50±5%RH) for 1000h and test it in accordance with the national standard GB / T 33332-2016 "Test method for dynamic shear strength of adhesive tape". In order to meet the product use requirements, the shear strength generally needs to be no less than 30MPa.

[0098] Impact strength test: Place the hot-pressed sample in a standard environment (23±1℃, 50±5%RH) for 1000h and test it in accordance with the national standard GB / T 6328-2021 "Adhesive Shear Impact Strength Test Method". In order to meet the product use requirements, the impact strength generally needs to be no less than 2.5J;

[0099] High temperature and anti-aging performance test: The hot-pressed samples were tested in accordance with the national standard GB / T32368-2015 "Test method for high temperature and high humidity aging of adhesive tapes". In order to meet the use requirements of the product, the high temperature and anti-aging performance generally requires that the samples can withstand double 85 (85°C, 85% RH×1000h) test, and the ratio of shear strength (α) and impact strength (β) of the film after the double 85 test is not less than 85% compared with the sample placed in the standard environment (23±1°C, 50±5% RH) for 1000h, indicating that it still has good shear strength and impact strength after high temperature and high humidity. Among them, α and β are calculated as follows:

[0100] α = shear strength after double 85 test / shear strength after 1000h in standard environment × 100%;

[0101] β = impact strength after double 85 test / impact strength after 1000h in standard environment × 100%.

[0102] Table 1 Test results of different embodiments and comparative examples

[0103]

[0104]

[0105] From the above test results, it can be seen that the adhesive prepared using the components in the specified amounts of the present invention exhibits excellent shear strength (≥30MPa) and impact strength (≥2.8J) after curing, and its performance decreases less after aging at 85°C / 85%RH-1000 hours, indicating that the adhesive of the present invention has excellent high temperature resistance and anti-aging properties.

[0106] The test results of Example 4 show that when non-benzoxazine resin is used in the adhesive, its shear strength and impact strength will decrease, and its high temperature resistance will decrease significantly.

[0107] The test results of Example 5 show that when the curing time of the thermoplastic polyurethane resin is long, the thermoplastic polyurethane resin cannot be fully cured within the 5-minute hot pressing time, resulting in a decrease in the shear strength and impact strength of the adhesive; when the weight average molecular weight of the thermoplastic polyurethane resin is lower than the specified range, its toughening effect and heat resistance are poor.

[0108] It can be seen from the test results of Comparative Example 1 and Comparative Example 2 that when the amount of the limited component of the present invention exceeds the limited range, the shear strength or impact strength will decrease, and the heat resistance will also decrease; if the benzoxazine resin is not added, the internal crosslinking of the adhesive is weakened, resulting in a decrease in its heat resistance; if the thermoplastic polyurethane resin is not added, its heat resistance decreases significantly.

[0109] It can be seen from the test results of comparative example 3 that when the amount of anhydride curing agent exceeds the specified range or does not contain anhydride curing agent, it will affect the crosslinking degree of the adhesive, and thus affect the shear strength and impact strength of the film after curing; when the acid value of the anhydride curing agent is lower than the specified range, due to the reduction of its crosslinkable functional groups, the overall crosslinking degree of the adhesive is reduced, resulting in a decrease in shear strength and impact strength; and when the acid value of the anhydride curing agent is higher than the specified range, due to the increase of its crosslinkable functional groups, the overall crosslinking degree of the adhesive is increased, and the excessive degree of curing causes the film to be too hard after curing, and the high temperature resistance performance is reduced.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. High temperature resistant adhesive, characterized in that: It includes the following components by weight: Wherein, the total weight of the epoxy resin, the benzoxazine resin and the thermoplastic polyurethane resin is 100 parts.

2. The high temperature resistant adhesive according to claim 1, characterized in that: The epoxy equivalent of the epoxy resin is 2,300 to 3,800 g / eq.

3. The high temperature resistant adhesive according to claim 1 or 2, characterized in that: The epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

4. The high temperature resistant adhesive according to claim 1, characterized in that: The benzoxazine resin has a glass transition temperature greater than 170°C.

5. The high temperature resistant adhesive according to claim 1 or 4, characterized in that: The benzoxazine resin includes at least one of a bisphenol A type benzoxazine resin, a bisphenol F type benzoxazine resin and a diamine type benzoxazine resin.

6. The high temperature resistant adhesive according to claim 1, characterized in that: The thermoplastic polyurethane resin is a heat-activated polyurethane resin; the curing time of the thermoplastic polyurethane is ≤5 minutes.

7. The high temperature resistant adhesive according to claim 1 or 6, characterized in that: The weight average molecular weight of the thermoplastic polyurethane resin is ≥70,000 g / mol.

8. The high temperature resistant adhesive according to claim 1, characterized in that: The acid value of the acid anhydride curing agent is 380-435 mgKOH / g.

9. An adhesive product, characterized in that: It comprises a support layer and an adhesive layer arranged on at least one side of the support layer; the adhesive layer is mainly made of the high temperature resistant adhesive according to any one of claims 1 to 8.

10. The adhesive product according to claim 9, characterized in that: The thickness of the adhesive layer is 50-100 μm.

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