Adhesive as well as preparation method and application thereof

Abstract

The invention discloses an adhesive as well as a preparation method and application thereof, and relates to the technical field of adhesives. The adhesive is prepared from the following raw materials: acrylate glue, epoxy resin and a curing agent, the preparation raw materials of the acrylate glue comprise glycidyl ester and an acrylate monomer; the mass ratio of the glycidyl ester to the acrylate monomer is 1: (5-12). The adhesive has excellent bonding strength for aramid paper and a polyester film, the temperature resistance and the solvent resistance (such as oil and water resistance) are improved, when the adhesive is used for bonding the aramid paper and the polyester film, the prepared composite insulating material also has excellent solvent resistance, the mechanical and electrical properties of the polyester film are kept, and the adhesive can be widely applied to the field of insulating materials. The motor is suitable for new energy motors.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesives, in particular to an adhesive, a preparation method and application thereof. BACKGROUND

[0002] New energy vehicles and power batteries are the core field of current global energy transformation, which are developing rapidly and attracting much attention. With the development of its technology and the improvement of consumer requirements, higher requirements are put forward for the mechanical, insulation, temperature resistance and safety of new energy vehicle motors under high current charging and discharging. At present, the insulation of new energy motor mainly adopts pure aramid paper and composite insulation paper. The composite insulation paper includes aramid paper and polyimide film composite, aramid paper and polyphenylene sulfide film composite, and aramid paper and polyethylene naphthalate film composite. These materials have the following problems: the voltage resistance of pure aramid paper cannot meet the requirements; the aramid paper and polyphenylene sulfide composite are expensive; the aramid paper and polyimide composite can well solve the requirements of temperature resistance and voltage resistance, but the leakage index is low, which also cannot meet the development needs of new energy vehicle motors.

[0003] In order to solve the above problems of the insulation material for new energy motor, the related technology proposes a technology of aramid paper and polyester film composite, which solves the problem of poor performance of traditional composite insulation paper in terms of temperature resistance, mechanical strength, voltage resistance and leakage index. However, the commonly used glue for the existing aramid paper and polyester film composite is polyurethane adhesive, which has good adhesion to aramid paper and polyester film, has the advantages of high bonding strength, fast curing speed, etc., but has poor solvent resistance, especially high-temperature oil and water resistance. Under the operation of high current and high speed, the motor generates a lot of heat, which needs to use oil instead of water to achieve rapid cooling of the motor, which leads to the fact that the electrical and mechanical properties of the aramid paper and polyester film after polyurethane adhesive composite and high temperature, high and low temperature oil and water aging decrease by more than 30%, which is difficult to meet the use requirements. SUMMARY

[0004] The present application aims at solving at least one of the above technical problems in the prior art. To this end, the purpose of the present application is to provide an adhesive, which is compounded with epoxy resin by using glue containing glycidyl ester and acrylic ester isooctyl ester, to improve the bonding strength of the adhesive to aramid paper and polyester film, and to improve the high-temperature water and oil resistance.

[0005] The second aspect of the present application is to provide a preparation method of the adhesive.

[0006] The third aspect of the present application is to provide a composite insulation material.

[0007] The fourth aspect of the present application is to provide a preparation method of the composite insulation material.

[0008] The fifth aspect of the present application provides an application of the adhesive or the composite insulating material.

[0009] To achieve the above-mentioned object, the technical scheme adopted by the present application is: The first aspect of the present application provides an adhesive, and the preparation raw materials of the adhesive include acrylate glue, epoxy resin and curing agent. The preparation raw materials of the acrylate glue include glycidyl ester and acrylate monomer; and the mass ratio of the glycidyl ester to the acrylate monomer is 1:(5-12).

[0010] The preparation raw materials of the acrylate glue of the present application include glycidyl ester and acrylate monomer, by controlling the proportion of the two, the glycidyl ester is effectively modified to the acrylate monomer, the crosslinking density of the adhesive is improved, and then the bonding strength, temperature resistance and solvent resistance of the adhesive are improved, and the flexibility of the glue is ensured, so that the poor bonding effect caused by the over-hardness of the adhesive after curing is avoided. At the same time, the epoxy resin is compounded with the acrylate glue to form an epoxy-modified acrylate, which can effectively improve the bonding strength of the adhesive to aramid paper and polyester film, improve the temperature resistance and solvent resistance, and maintain the mechanical strength and electrical mechanical properties of the polyester film.

[0011] In some embodiments, the mass ratio of the glycidyl ester to the acrylate is 1:(6-10). Specifically, the mass ratio of the glycidyl ester to the isooctyl acrylate can be 1:6, 1:7, 1:8, 1:9 or 1:10, or other ranges composed of these mass ratios, for example, 1:(7-10), 1:(8-10), 1:(9-10).

[0012] In some embodiments, the acrylate monomer includes isooctyl acrylate, butyl acrylate, hydroxyethyl acrylate and methyl methacrylate.

[0013] In some embodiments, the preparation raw materials of the acrylate glue further include styrene, methyl methacrylate and acrylonitrile; and the mass ratio of the styrene, methyl methacrylate and acrylonitrile to the isooctyl acrylate is independently selected from any value in 1:(2-20).

[0014] It should be understood that the "mass ratio of the styrene, methyl methacrylate and acrylonitrile to the isooctyl acrylate" refers to the mass ratio of the styrene to the isooctyl acrylate, the mass ratio of the methyl methacrylate to the isooctyl acrylate and the mass ratio of the acrylonitrile to the isooctyl acrylate.

[0015] Specifically, the mass ratio of each of the styrene, methyl methacrylate and acrylonitrile to the isooctyl acrylate can be 1:2, 1:3, 1:5, 1:7, 1:10, 1:12, 1:14, 1:15, 1:18 or 1:20, or other ranges consisting of these mass ratios, for example 1:(3~20), 1:(5~20), 1:(7~20), 1:(10~20), 1:(12~20), 1:(15~20) or 1:(18~20).

[0016] In some embodiments, the adhesive comprises the following components by mass fraction: 100 parts of acrylic adhesive, 7~15 parts of epoxy resin, 8~16 parts of curing agent.

[0017] In some specific embodiments, the adhesive comprises the following components by mass fraction: 100 parts of acrylic adhesive, 8~10 parts of epoxy resin, 9~11 parts of curing agent.

[0018] In some embodiments, the epoxy resin comprises bisphenol A type epoxy resin; the curing agent comprises acid anhydride curing agent.

[0019] In some embodiments, the raw materials for preparing the acrylic adhesive comprise the following components by mass fraction: 80~150 parts of isooctyl acrylate, 40~80 parts of butyl acrylate, 5~20 parts of acrylic acid, 15~30 parts of hydroxyethyl acrylate, 20~50 parts of glycidyl ester, 5~35 parts of styrene, 5~35 parts of methyl methacrylate, 5~20 parts of acrylonitrile, 1~15 parts of vinyl silicone oil, 0.5~3 parts of initiator, 250~450 parts of solvent.

[0020] In some other embodiments, the raw materials for preparing the acrylic adhesive comprise the following components by mass fraction: 100~150 parts of isooctyl acrylate, 50~70 parts of butyl acrylate, 10~20 parts of acrylic acid, 20~30 parts of hydroxyethyl acrylate, 25~45 parts of glycidyl ester, 20~35 parts of styrene, 10~30 parts of methyl methacrylate, 5~25 parts of acrylonitrile, 1~10 parts of vinyl silicone oil, 0.5~2 parts of initiator, 260~430 parts of solvent.

[0021] In some other embodiments, the raw materials for preparing the acrylic adhesive comprise the following components by mass fraction: Isopropyl acrylate 120~130 parts, butyl acrylate 55~65 parts, acrylic acid 10~20 parts, hydroxyethyl acrylate 20~30 parts, glycidyl ester 25~35 parts, styrene 25~30 parts, methyl methacrylate 10~30 parts, acrylonitrile 8~20 parts, vinyl silicone oil 1~5 parts, initiator 1~2 parts, solvent 300~400 parts.

[0022] Specifically, the acrylic adhesive is obtained by polymerization of the preparation raw materials at 70~90℃.

[0023] In some embodiments, the initiator includes at least one of azobisisobutyronitrile, azobisisoheptyl nitrile, benzoyl peroxide, di-tert-butyl peroxide.

[0024] In some embodiments, the solvent includes at least one of ethyl acetate, butyl acetate, acetone, butanone.

[0025] The second aspect of the present application provides a preparation method of the adhesive of the first aspect of the present application, characterized in that, comprising the following steps: Mixing the acrylic adhesive, the epoxy resin and the curing agent to obtain the adhesive.

[0026] In some embodiments, the preparation method of the acrylic adhesive comprises the following steps: mixing the raw materials of the acrylic adhesive to obtain the acrylic adhesive.

[0027] The third aspect of the present application provides a composite insulating material, which comprises the adhesive of the first aspect of the present application.

[0028] In some embodiments, the composite insulating material comprises aramid paper, adhesive layer and polyester film arranged in a stack; the preparation raw material of the adhesive layer is the adhesive.

[0029] Specifically, the stack structure of the composite insulating material is aramid paper, adhesive layer, polyester film, adhesive layer, aramid paper.

[0030] In some embodiments, the thickness of the adhesive layer formed by the adhesive in the composite insulating material is 10~50μm.

[0031] In some other embodiments, the thickness of the adhesive layer formed by the adhesive in the composite insulating material is 20~40μm.

[0032] In some embodiments, the thickness of the aramid paper is 30~80μm.

[0033] In some embodiments, the thickness of the polyester film is 36~125μm.

[0034] In some embodiments, the thickness of the polyester film is 50-100 μm.

[0035] The fourth aspect of the present application provides a preparation method of the composite insulating material according to the third aspect of the present application, comprising the following steps: The adhesive is coated on at least one surface of the polyester film, the aramid paper is adhered to the adhesive, and after baking, hot pressing and curing, the composite insulating material is obtained.

[0036] In some embodiments, the adhesive is coated on both surfaces of the polyester film, and the thickness of the adhesive on a single surface is 10-50 μm. It should be understood that the composite insulating material has a layer structure of aramid paper-adhesive-polyester film-adhesive-aramid paper.

[0037] In some embodiments, the temperature of the hot pressing is 70-90℃.

[0038] In some embodiments, the temperature of the curing is 120-180℃.

[0039] In some embodiments, the hot pressing is followed by a maturation step before the curing; the temperature of the maturation is 90-110℃.

[0040] The fifth aspect of the present application provides an application of the adhesive according to the first aspect of the present application or the composite insulating material according to the third aspect of the present application in the field of new energy motors.

[0041] Compared with the prior art, the present application has the following beneficial effects: The adhesive provided by the present application is prepared by modifying glycidyl ester with isooctyl acrylate to prepare an acrylate adhesive, and adding epoxy resin to modify the adhesive with epoxy, and further adding other monomers such as acrylic acid and acrylate to improve the crosslinking density. The adhesive has excellent bonding strength for aramid paper and polyester film, and the temperature resistance and solvent resistance (such as oil and water resistance) are also improved. The adhesive is used to bond aramid paper and polyester film, and the prepared composite insulating material also has excellent solvent resistance, and maintains the mechanical and electrical properties of the polyester film, and is suitable for use in new energy motors. DETAILED DESCRIPTION

[0042] The content of the present application is further described in detail through specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial channels or can be obtained by existing technical methods. Unless otherwise specified, the test or test method is a conventional method in the art.

[0043] The following is described in detail with specific examples and comparative examples.

[0044] The glycidyl ester in the following examples is a conventional commercially available glycidyl methacrylate; the bisphenol A type epoxy resin is Epon 128. The remaining raw materials are also conventional commercially available materials.

[0045] Example 1 An adhesive, the formulation of which is shown in Tables 1 and 2, is prepared by the following steps: Isocetyl acrylate, butyl acrylate, acrylic acid, hydroxyethyl acrylate, glycidyl ester, styrene, methyl methacrylate, acrylonitrile, vinyl silicone oil, azobisisobutyronitrile and ethyl acetate are mixed and then polymerized at 80°C for 7h to form an acrylate adhesive. The acrylate adhesive is then mixed with bisphenol A type epoxy resin and an anhydride curing agent (methyl tetrahydrophthalic anhydride) to obtain the adhesive.

[0046] Table 1 Formulation of the acrylate adhesive of Example 1

[0047] Table 2 Formulation of the adhesive of Example 1

[0048] Example 2 An adhesive, compared with Example 1, differs in the amounts of isocetyl acrylate and glycidyl ester, bisphenol A type epoxy resin and methyl tetrahydrophthalic anhydride. The specific formulation is shown in Tables 3 and 4, and the preparation method is the same as that of Example 1.

[0049] Table 3 Formulation of the adhesive of Example 2

[0050] Table 4 Formulation of the adhesive of Example 2

[0051] Example 3 An adhesive, compared with Example 2, differs in the amounts of glycidyl ester, styrene, acrylonitrile and methyl methacrylate. The specific formulation is shown in Tables 5 and 6, and the preparation method is the same as that of Example 1.

[0052] Table 5 Formulation of the adhesive of Example 3

[0053] Table 6 Formulation of the adhesive of Example 3

[0054] Comparative Example 1 A kind of adhesive, compared with example 2, glycidyl ester is not added, see table 7 and table 8 for specific formulation, preparation method is same with example 1.

[0055] Table 7 Formulation table of adhesive of comparative example 1

[0056] Table 8 Formulation table of adhesive of comparative example 1

[0057] Comparative example 2 A kind of adhesive, compared with example 2, the amount of glycidyl ester is different, see table 9 and table 10 for specific formulation, preparation method is same with example 1.

[0058] Table 9 Formulation table of adhesive of comparative example 2

[0059] Table 10 Formulation table of adhesive of comparative example 2

[0060] Comparative example 3 A kind of adhesive, compared with example 2, the amount of glycidyl ester, styrene and methyl methacrylate is different, see table 11 and table 12 for specific formulation, preparation method is same with example 1.

[0061] Table 11 Formulation table of adhesive of comparative example 3

[0062] Table 12 Formulation table of adhesive of comparative example 3

[0063] Comparative example 4 A kind of adhesive, compared with example 2, the amount of styrene, acrylonitrile and methyl methacrylate is different, see table 13 and table 14 for specific formulation, preparation method is same with example 1.

[0064] Table 13 Formulation table of adhesive of comparative example 4

[0065] Table 14 Formulation table of adhesive of comparative example 4

[0066] Application example The adhesive obtained by the above example and comparative example is used to prepare composite insulation material, and the preparation method is as follows: The adhesive was coated on both sides of the polyester film (thickness 100 μm), the adhesive thickness of single side coating was 30 μm, the coating speed was 15 m / min, and the pressure of the compression roller was 3 kg; then the aramid paper (thickness 50 μm) was adhered on the upper and lower surfaces of the polyester film, i.e. aramid paper-adhesive-polyester film-adhesive-aramid paper from top to bottom, after baking, 80℃ hot pressing, 100℃ curing for 8 h and 150℃ curing for 4 h, the composite insulation material was obtained.

[0067] Test Example 1. Adhesion effect: visually checking the adhesion of the aramid paper in the composite insulation material, whether there is delamination, blistering or not.

[0068] 2. High temperature oil resistance test: the composite insulation material was immersed in 180℃ mechanical oil (gearbox oil ATF) for 200 h, the breakdown voltage before and after immersion was tested, and the retention rate of the breakdown voltage (breakdown voltage after immersion / breakdown voltage before immersion x 100%) was calculated.

[0069] The test results are shown in the following Table 15.

[0070] Table 15 Performance test results of the adhesive prepared composite insulation material of the examples and comparative examples

[0071] From the results in Table 15, it can be seen that the composite insulation material prepared by using the adhesive of the present application has no abnormality in the adhesion of the aramid paper, and does not have delamination and blistering, and after high temperature hot oil aging at 180℃ / 200 h, the breakdown voltage can be maintained at more than 70% of that before aging, which ensures good adhesion effect and significantly improves the high temperature solvent resistance, i.e. the adhesive provided by the present application has excellent solvent resistance, especially high temperature oil resistance, and has good long-term aging resistance.

[0072] The adhesive used in Comparative Example 1 does not add glycidyl ester, and after modification, the adhesive lacks the crosslinking reaction with the anhydride curing agent, the bonding effect of the adhesive on aramid paper and polyester film is reduced, and after curing, delamination and bubbling occur, and the retention rate of breakdown voltage is also reduced after high-temperature mechanical oil aging. In Comparative Example 2, the amount of glycidyl ester is high, which is not conducive to the bonding effect and solvent resistance of the adhesive, and delamination occurs after curing, and the retention rate of breakdown voltage is less than 60%. Comparative Example 3 has a higher ratio of glycidyl ester to isooctyl acrylate compared to Example 2, and the amount of styrene and methyl methacrylate is also increased, which reduces the bonding effect and solvent resistance of the adhesive, and delamination occurs, and the retention rate of breakdown voltage is less than 60%. Comparative Example 4 has a lower amount of styrene, acrylonitrile, and methyl methacrylate compared to Example 2, and the resulting adhesive also has a performance decline, which leads to a decline in the performance of the composite insulating material.

[0073] In summary, the adhesive provided by the present application is prepared by modifying isooctyl acrylate with glycidyl ester to prepare an acrylic ester adhesive, and adding epoxy resin to modify the adhesive with epoxy, and further adding other monomers such as acrylic acid and acrylate to increase the crosslinking density, so that the synthesized adhesive has excellent bonding strength on aramid paper and polyester film, and the temperature resistance and solvent resistance (such as oil and water resistance) are also improved. The adhesive is used to bond aramid paper and polyester film, and the prepared composite insulating material also has excellent solvent resistance, and maintains the mechanical and electrical properties of the polyester film, and is suitable for use in new energy motors.

[0074] The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, and are included in the protection scope of the present application.

Claims

1. An adhesive, characterized in that, The raw materials for preparing the adhesive include acrylate adhesives, epoxy resins, and curing agents; The raw materials for preparing the acrylate adhesive include glycidyl ester and acrylate monomers; the mass ratio of glycidyl ester to acrylate monomers is 1:(5~12).

2. The adhesive according to claim 1, characterized in that, The acrylate monomers include isooctyl acrylate, butyl acrylate, hydroxyethyl acrylate, and methyl methacrylate; And / or, the raw materials for preparing the acrylate adhesive further include styrene, methyl methacrylate and acrylonitrile; the mass ratio of styrene, methyl methacrylate and acrylonitrile to isooctyl acrylate is independently selected from any value in the range of 1:(2~20).

3. The adhesive according to claim 1, characterized in that, The adhesive comprises the following components in parts by weight: 100 parts acrylic adhesive, 7-15 parts epoxy resin, and 8-16 parts curing agent.

4. The adhesive according to any one of claims 1 to 3, characterized in that, The raw materials for preparing the acrylic adhesive, by weight, include the following components: 80-150 parts of isooctyl acrylate, 40-80 parts of butyl acrylate, 5-20 parts of acrylic acid, 15-30 parts of hydroxyethyl acrylate, 20-50 parts of glycidyl acrylate, 5-35 parts of styrene, 5-35 parts of methyl methacrylate, 5-25 parts of acrylonitrile, 1-15 parts of vinyl silicone oil, 0.5-3 parts of initiator, and 250-450 parts of solvent.

5. The adhesive according to claim 4, characterized in that, The initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, and di-tert-butyl peroxide; And / or, the solvent includes at least one of ethyl acetate, butyl acetate, and toluene.

6. A method for preparing the adhesive according to any one of claims 1 to 5, characterized in that, Includes the following steps: The adhesive is obtained by mixing acrylic adhesive, epoxy resin and curing agent.

7. A composite insulating material, characterized in that, The composite insulating material includes the adhesive as described in any one of claims 1 to 5.

8. The composite insulating material according to claim 7, characterized in that, The composite insulating material comprises aramid paper, an adhesive layer, and a polyester film stacked together; the adhesive layer is prepared from the aforementioned adhesive. And / or, in the composite insulating material, the thickness of the adhesive layer formed by the adhesive is 10~50μm.

9. A method for preparing the composite insulating material according to claim 7 or 8, characterized in that, Includes the following steps: The adhesive is applied to at least one surface of a polyester film, and the adhesive layer formed by the adhesive is bonded to aramid paper. After baking, hot pressing, and curing, the composite insulating material is obtained.

10. The application of an adhesive according to any one of claims 1 to 5, or a composite insulating material according to any one of claims 7 to 8, in the field of new energy motors.

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