Waterproof insulating adhesive tape with super-soft ethylene propylene rubber base material

Abstract

The invention discloses a waterproof insulating tape with a super-soft ethylene propylene rubber base material and a preparation method thereof. The adhesive tape is prepared from monomers (methyl methacrylate, butyl acrylate and 2-ethylhexyl acrylate), modified kaolin, an initiator and an auxiliary agent according to a specific proportion, wherein the modified kaolin is prepared from a silane coupling agent, a modifier and a grafting agent. An adhesive tape obtained by mixing, heating, coating and baking is adhered to the surface of an ethylene propylene rubber base material to form the waterproof insulating adhesive tape. The adhesive tape provided by the invention has excellent initial adhesion, peel strength, holding power and shear strength, and also has excellent flame retardant property, and effectively solves the problem that the adhesive property and flame retardant property of the existing adhesive tape product are difficult to have at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of adhesive tapes, in particular to a waterproof insulating adhesive tape with an ultra-soft ethylene-propylene rubber substrate. Background Art

[0002] With the rapid development of modern industry, the demand for high-performance insulating materials is growing, especially in the electronics, electrical and automotive industries. The demand for tapes with both good insulating properties and waterproof properties is particularly urgent. As a high-performance rubber material, EPDM is widely used in the manufacture of various tape products due to its excellent heat resistance, weather resistance and chemical resistance. However, traditional EPDM rubber tapes still have certain limitations in terms of softness, waterproofness and insulation performance.

[0003] CN105038634A discloses an acrylic waterproof insulating tape and a preparation method thereof, which consists of three layers: an acrylic coating, a cloth base layer and a hot-melt pressure-sensitive adhesive coating. The acrylic coating can play a waterproof role, and can increase the insulation withstand voltage of the insulating tape from the traditional 1kV×1min to 3kV×10min, with better insulation. At the same time, the insulating tape of the invention also improves the adhesive properties of the hot-melt pressure-sensitive adhesive coating, such as the adhesive properties of the sustained adhesion, initial adhesion and peeling force, so it can meet the temperature requirements of -10℃-80℃, and has good temperature resistance. The acrylic waterproof insulating tape prepared by the invention method has good quality, is not easy to debond, is easy to unwind without splitting, and has low cost, is suitable for industrial and civilian use, and has strong practicality. However, the waterproof insulating tape prepared by this method has poor tensile properties and is easy to burn when encountering a fire.

[0004] CN108192512A discloses a new type of environmentally friendly fireproof tape and its preparation. The fireproof tape includes a base material layer, on which a layer of adhesive is coated; the base material layer is made of a flame retardant material, and the adhesive is a flame retardant acrylic adhesive. The new type of environmentally friendly fireproof tape provided by the invention has excellent initial adhesion, peel strength, sustained adhesion and shear strength, as well as excellent flame retardant properties, which cleverly solves the problem that the bonding properties and flame retardant properties cannot be achieved at the same time in existing adhesive products. The obtained fireproof tape has excellent properties in various aspects and is suitable for transformers, battery end insulation and other fields with high requirements for high temperature resistance, fire resistance, insulation and other properties, such as automobiles, mobile phones, batteries, etc. However, the fireproof tape prepared by this method has poor water resistance and cannot meet the needs of use in multiple scenarios. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to improve the waterproof performance of the waterproof insulating tape with an ultra-soft EPDM rubber substrate, increase the initial adhesion and flame retardancy, expand the application scope of the waterproof insulating tape, and enhance the different application scenarios of the waterproof insulating tape.

[0006] To achieve the above object, the present invention provides a waterproof and insulating tape with a super-soft ethylene-propylene rubber substrate, which, by weight, comprises the following components in parts by weight: 30-50 parts of a mixed monomer, 5-10 parts of modified kaolin, 1-3 parts of an initiator, 1-3 parts of an auxiliary agent, 5-20 parts of a solvent, 40-60 parts of a diluent, and 2-7 parts of a crosslinking agent; the modified kaolin is prepared from a silane coupling agent, a modifier, and a grafting agent.

[0007] Preferably, the mixed monomer is a mixture of methyl methacrylate, butyl acrylate, and isooctyl acrylate.

[0008] Preferably, the preparation method of the modified kaolin comprises the following steps, by weight: S1. Weigh 8-15 parts of kaolin, add 15-35 parts of a hydrolyzed solution of a silane coupling agent under infrared light irradiation, stir evenly, dry, wash 1-3 times by ethanol centrifugation, and then dry to obtain A; S2. Weigh 8-15 parts of A obtained in step S1, add 15-30 parts of a grafting agent, add 15-35 parts of acetone, perform ultrasonic dispersion, stir evenly under infrared light irradiation, dry, wash by acetone centrifugation, and then dry to obtain B; S3. Weigh 8-15 parts of B obtained in step S2, add 30-60 parts of a modifier, add 25-50 parts of acetone, perform ultrasonic dispersion, stir evenly under infrared light irradiation, dry, wash by acetone centrifugation, and then dry to obtain the modified kaolin.

[0009] Preferably, the grafting agent is dodecylbenzene-2,4-diisocyanate.

[0010] Preferably, the modifier is any one of 4-aminononylphosphonic acid, eicosylamine, and behenyl primary amine.

[0011] More preferably, the modifier is 4-aminononylphosphonic acid.

[0012] Preferably, the initiator is benzoyl peroxide.

[0013] Preferably, the stirring time is 50-80 min.

[0014] Preferably, the ultrasonic dispersion time is 8-15 min.

[0015] Preferably, the solvent is ethyl acetate.

[0016] Preferably, the diluent is xylene.

[0017] Preferably, the crosslinking agent is aziridine.

[0018] The present invention also discloses a preparation method of a waterproof and insulating tape with a super-soft ethylene-propylene rubber substrate.

[0019] A preparation method of a waterproof and insulating tape with a super-soft ethylene-propylene rubber substrate, comprising the following steps, by weight: Step 1: Mix 30 - 50 parts of mixed monomers, 5 - 10 parts of modified kaolin, 1 - 3 parts of initiator, 1 - 3 parts of auxiliary agent and 5 - 20 parts of solvent evenly, heat to reflux, keep the reaction for 3 - 4 h, cool, and discharge to obtain a raw material liquid; Step 2: Add 40 - 60 parts of diluent and 2 - 7 parts of crosslinking agent to the raw material liquid in Step 1, stir evenly to obtain a coating liquid; Step 3: Uniformly coat a non-silicon release agent on one side of the ethylene-propylene rubber substrate, cure it, uniformly coat the coating liquid in Step 2 on the other side of the ethylene-propylene rubber substrate, cure it to obtain an adhesive layer, and after cooling, winding and cutting, obtain a waterproof and insulating tape with a super-soft ethylene-propylene rubber substrate.

[0020] Technical concept: When preparing a waterproof and insulating tape with a super-soft ethylene-propylene rubber substrate, adding kaolin is mainly to improve the mechanical strength and tear resistance of the tape, reduce production costs, improve processing performance, and enhance thermal stability and dimensional stability. Kaolin, as a relatively inexpensive filler, can effectively improve multiple physical properties of the tape. However, during the addition of kaolin, dispersion problems may be encountered, resulting in inconsistent product performance. The surface of kaolin is grafted with an organic coupling agent by a chemical method, thereby changing the surface properties of kaolin from hydrophilic to lipophilic, reducing the surface energy, and thus improving the compatibility with polymer materials. The lipophilic organic long chain can entangle with the polymer chain, or the lipophilic long chain with active groups can react with polymer molecules to form chemical bonds, improving the compatibility between kaolin and polymer molecules and enhancing the performance of the waterproof and insulating tape.

[0021] In this formulation, the functions of the substances used in the modified kaolin are as follows: Kaolin, as the main inorganic filler, is used to improve the mechanical strength and tear resistance of the tape while reducing costs.

[0022] Silane coupling agent KH560 is used to modify kaolin. By the reaction of its hydrolysis solution with the hydroxyl groups of kaolin, the compatibility between kaolin and organic polymers is enhanced, and the dispersion and interfacial bonding force of the filler are improved.

[0023] Grafting agent: React with kaolin modified by silane coupling agent KH560 to introduce long alkyl chains, enhance the compatibility between kaolin and polymers, and provide additional crosslinking points.

[0024] Modifier: Introduce amino functional groups, which can react with isocyanate groups or hydroxyl groups in the kaolin polymer macromolecules grafted by grafting agents, improve the interfacial adhesion strength of the polymer, and improve the properties of kaolin.

[0025] Acetone is used as a solvent to dissolve the modifier and grafting agent, facilitating their mixing and reaction with kaolin.

[0026] Ethanol is used to wash the modified kaolin to remove unreacted modifier and grafting agent, ensuring uniform surface modification of kaolin.

[0027] Advantages of the present invention: 1. Compared with the prior art, the present invention prepares a tape by mixing modified kaolin with other raw materials, improving the mechanical strength, tear resistance, thermal stability and flame retardancy of the ethylene-propylene rubber-based waterproof and insulating tape. At the same time, the introduction of long alkyl chains and phosphoric acid groups in the modifier enhances the waterproof and flame retardant properties of the tape, enabling the tape to have better water resistance and flame retardancy while maintaining its ultra-soft characteristics.

[0028] 2. Compared with the prior art, the preparation method of the present invention realizes the uniform dispersion of kaolin in the ethylene-propylene rubber substrate by precisely controlling the preparation steps of the modified kaolin and the coating process of the tape. In addition, the tape of the present invention can maintain good adhesion performance within a wide temperature range, meeting the application requirements under different environmental conditions. Detailed implementation manners

[0029] Parameters and sources of specific chemical substances are used.

[0030] 4-aminononadecylphosphonic acid, phosphonic acid, (4-aminononadecyl)-, CAS No.: 596820-13-2.

[0031] Dodecylbenzene-2,4-diisocyanate, CAS No.: 93859-04-2.

[0032] Kaolin, 325 mesh, Longyan Kaolin Co., Ltd.

[0033] Polyethyleneimine octadecylurea, model: RP-20, Tianmen Hengchang Chemical Co., Ltd.

[0034] Ethylene-propylene rubber, grade: Mitsui 3092M, ethylene mass fraction 65%, ENB mass fraction 4.6%, Shanghai Sinopec Mitsui Elastomers Co., Ltd.

[0035] Example 1 A preparation method of a waterproof and insulating tape with a super-soft ethylene-propylene rubber substrate, comprising the following steps: Step 1: Mix 10 kg of methyl methacrylate, 15 kg of butyl acrylate, 15 kg of isooctyl acrylate, 8 kg of modified kaolin, 2 kg of benzoyl peroxide, 1 kg of stearic acid, and 7 kg of ethyl acetate at 2000 rpm for 20 min, heat to 100 °C for reflux, keep warm for 3 h, cool to 25 °C, and discharge to obtain a raw material liquid; Step 2: Add 50 kg of xylene and 3 kg of aziridine to the raw material liquid in Step 1, and mix at 2000 rpm for 30 min to obtain a coating liquid; Step 3: Mix 5 kg of polyethyleneimine octadecylurea and 3 kg of water at 200 rpm for 15 min, uniformly coat one side of the ethylene-propylene rubber substrate, then place it in an oven at 90 °C and cure for 15 min. Uniformly coat the coating liquid in Step 2 on the other side of the ethylene-propylene rubber substrate, place it in an oven at 120 °C and cure for 50 min. After completion, a pressure-sensitive adhesive layer is obtained. After cooling, winding, and cutting, a waterproof and insulating tape with a super-soft ethylene-propylene rubber substrate is obtained.

[0036] Among them, the preparation method of the modified kaolin comprises the following steps: S1: Weigh 8 kg of kaolin, add 20 kg of silane coupling agent KH560 hydrolysis solution under infrared light irradiation, stir at 200 rpm for 30 min, dry at 75 °C for 5.5 h, wash with ethanol by centrifugation 3 times, and bake at 115 °C for 20 h to obtain solid A; S2: Weigh 8 kg of solid A in Step S1, add 16 kg of dodecylbenzene-2,4-diisocyanate, add 20 L of acetone, disperse by ultrasonic wave at 50 Hz for 45 min, stir at 200 rpm for 30 min under infrared light irradiation, dry at 75 °C for 5.5 h, wash with acetone by centrifugation 3 times, and dry at 60 °C for 24 h to obtain solid B; S3: Weigh 12 kg of solid B in Step S2, add 30 kg of 4-aminononylphosphonic acid, add 35 L of acetone, disperse by ultrasonic wave at 50 Hz for 45 min, stir at 200 rpm for 30 min under infrared light irradiation, dry at 75 °C for 5.5 h, wash with acetone by centrifugation 3 times, and dry at 60 °C for 24 h to obtain modified kaolin.

[0037] Among them, the preparation method of the silane coupling agent KH560 hydrolysis solution comprises the following steps: Weigh 1 kg of silane coupling agent KH560, 1 L of water, and 20 L of ethanol, and stir at 200 rpm for 1 h at 42 °C to obtain the silane coupling agent KH560 hydrolysis solution.

[0038] Example 2 The difference between Example 2 and Example 1 of this application is that the 4-aminononylphosphonic acid in Example 1 is replaced by behenyl primary amine.

[0039] Example 3 The difference between Example 3 and Example 1 of this application is that the 4-aminononylphosphonic acid in Example 1 is replaced by eicosylamine.

[0040] Comparative Example 1 The difference between Comparative Example 1 and Example 1 of this application is that the 4-aminononylphosphonic acid in Example 1 is replaced by octadecylamine.

[0041] Comparative Example 2 The difference between Comparative Example 2 and Example 1 of this application is that the dodecylbenzene-2,4-diisocyanate in Example 1 is replaced by isophorone diisocyanate.

[0042] Comparative Example 3 A preparation method of a waterproof and insulating tape with a super soft ethylene-propylene rubber substrate includes the following steps: Step 1: Mix 10 kg of methyl methacrylate, 15 kg of a mixture of butyl acrylate and 15 kg of isooctyl acrylate, 8 kg of kaolin, 2 kg of benzoyl peroxide, 1 kg of stearic acid, and 7 kg of ethyl acetate at 2000 rpm for 20 min, heat to 100 °C for reflux, keep warm for 3 h, cool to 25 °C, and discharge to obtain a raw material liquid; Step 2: Add 50 kg of xylene and 3 kg of aziridine to the raw material liquid in Step 1, and mix at 2000 rpm for 30 min to obtain a coating liquid; Step 3: Uniformly coat a non-silicone release agent on one side of the ethylene-propylene rubber substrate, then place it in an oven at 90 °C and cure for 15 min. Uniformly coat the coating liquid in Step 2 on the other side of the ethylene-propylene rubber substrate, place it in an oven at 120 °C and cure for 50 min. After completion, obtain an adhesive layer, and after cooling, winding, and cutting, obtain a waterproof and insulating tape with a super soft ethylene-propylene rubber substrate.

[0043] Test Example 1 According to GB / T 4852-2002 "Test Method for Tack of Pressure-Sensitive Adhesive Tapes (Rolling Ball Method)", the initial tack of the waterproof and insulating tapes prepared in Examples 1-3 and Comparative Examples 1-3 was tested. The rolling ball ramp stop test method was used, and the measurement angle was 10°.

[0044] Determined with reference to GB / T 4851-2014 "Test Method for Adhesive Holding Power of Adhesive Tapes". Stick a 20 mm × 40 mm sample tape on stainless steel, hang a 1000 g weight below, and observe whether the sample moves down within 1 hour. If it moves down, record the moving distance.

[0045] The water contact angle of the waterproof insulating adhesives prepared in Examples 1-3 and Comparative Examples 1-3 was measured using a JC2000D2G type contact angle tester to evaluate the waterproof performance of the samples.

[0046] It was determined with reference to GB / T15903-1995 "Test Method for Flammability of Pressure-Sensitive Adhesive Tapes (Hanging Method)".

[0047] The flame retardant performance of the fireproof tape was tested with reference to the flame retardant performance of thin film materials in UL94 American flame retardant material standard.

[0048] The test results are shown in Table 1: Table 1 Performance Test of Waterproof Insulating Tape Test Example 2 The waterproof insulating tapes of Examples 1-3 and Comparative Examples 1-3 were detected as follows: The voltage was 120V, the constant voltage time was 100 minutes. After the formation was completed, it was boiled, washed and dried, and the leakage current was measured; The waterproof insulating tapes of Examples 1-3 and Comparative Examples 1-3 were immersed in organic solvent benzene for 10 seconds, taken out and the solvent on the sample surface was cleaned, then immersed in a one-ten-thousandth ethylene glycol phosphate solution at 80°C, the voltage was 160V, taken out after constant voltage for 1 minute, boiled, washed and dried at 200°C, the sample was encapsulated after being coated with a film, and its breakdown voltage Ub was tested. The thickness of the waterproof insulating tapes of Examples 1-3 and Comparative Examples 1-3 was measured around the breakdown point, at least three points were measured, with an accuracy of 0.2μm, and the arithmetic mean was taken as the thickness d of the sample. Through the breakdown strength formula, Eb = Ub / d, the breakdown strength Eb was calculated; At room temperature of 25°C, using an HP4278 bridge, the dielectric properties of the waterproof insulating tapes of Examples 1-3 and Comparative Examples 1-3 were tested at 1MHz and 1.0V (AC); Using an SF2512 fast insulation machine, a DC rated voltage of 100V was applied for 10 seconds to test the insulation resistance of the waterproof insulating tapes of Examples 1-3 and Comparative Examples 1-3. The test results are shown in Table 2: Table 2 Insulation Performance Test Comparing the test results in Examples 1-3 and Comparative Example 1, it is found that the waterproofing effect, flame retardant effect, and initial adhesiveness of the waterproof insulating tape in Example 1 are the best. The possible reason is the use of different modifiers. The modifier can modify the kaolin grafted with a grafting agent and a silane coupling agent, thereby improving the dispersibility of kaolin in the ethylene-propylene rubber substrate. Comparing the modifiers in Examples 1-3 and Comparative Example 1, the modifier in Example 1 contains an amino functional group in addition to the amino functional group can react with the hydroxyl functional group contained in the kaolin polymer grafted with a grafting agent and a silane coupling agent, thereby introducing the long alkyl chain contained in the modifier into the polymer. The lipophilic organic long chain can entangle with the polymer chain, or the amino group in the lipophilic long chain can react with the hydroxyl group contained in the polymer to form a chemical bond, thereby improving the compatibility between kaolin and the polymer and enhancing the performance of the modified kaolin material. The modifier in Example 1 also contains a phosphate group. When burning in the presence of fire, the phosphate group will decompose into metaphosphoric acid and polyphosphoric acid, and a phosphoric acid layer will be generated during the decomposition process, covering the surface of the combustible material and isolating the supply of oxygen, thereby stopping the combustion. Moreover, the presence of polyphosphoric acid will promote the combustion decomposition of the composite material to proceed in the direction of carbonization, thereby preventing combustion. The modifiers in Examples 2-3 and Comparative Example 2 have poorer flame retardant performance because they do not contain a phosphate group.

[0049] Comparing the test results in Example 1 and Comparative Example 2, it is found that the waterproofing effect of the waterproof insulating tape in Example 1 is better, probably because different grafting agents are used in the two. The grafting agent can graft the kaolin modified with a silane coupling agent. The isocyanate group contained in the grafting agent can react with the hydroxyl group in the kaolin modified with a silane coupling agent. The grafting agent in Example 1 contains a long alkyl chain and a benzene ring rigid structure in addition to the isocyanate group. First, due to its stable conjugated π electron system, the benzene ring structure is hydrophobic and is not easily hydrogen-bonded or affinity-interacted with water molecules. Second, the long alkyl chain is also hydrophobic, and its non-polar hydrocarbon chain segment is not easily interacted with water molecules, and can form a physical barrier to hinder the intrusion of water molecules. Moreover, the long alkyl chains can entangle with each other in the material, increasing the intermolecular van der Waals force, thereby increasing the overall density and compactness of the polymer, reducing the penetration channels of water molecules, and enhancing the waterproof performance. Therefore, the water contact angle of the waterproof insulating tape prepared in Example 1 is the largest and the waterproof property is better.

[0050] Comparing the test results in Example 1 and Comparative Example 3, it is found that the waterproofing effect, flame retardancy and initial tack of the waterproof insulating tape in the example are the best. The possible reason is that the modified kaolin shows better dispersibility in the ethylene-propylene rubber substrate. The unmodified kaolin is mainly combined with the rubber substrate through physical adsorption, and this binding force is relatively weak, not as strong as the binding force between the chemically modified kaolin and the rubber substrate. At the same time, the unmodified kaolin is prone to agglomeration in the ethylene-propylene rubber, which will reduce its dispersibility in the ethylene-propylene rubber. Therefore, the viscosity of the waterproof insulating tape prepared in Comparative Example 3 is worse.

[0051] The leakage current and dielectric loss of the acrylic tape materials prepared in Examples 1-3 and Comparative Examples 1-3 are smaller than those in Comparative Example 1, and the breakdown strength and dielectric constant are higher than those in Comparative Example 1, indicating that the waterproof insulating tape of the present invention has good insulation performance.

Claims

1. A waterproof insulating tape based on super soft EPDM rubber, characterized in that: The invention comprises the following components in parts by weight: 30-50 parts of mixed monomers, 5-10 parts of modified kaolin, 1-3 parts of initiator, 1-3 parts of auxiliary agent, 5-20 parts of solvent, 40-60 parts of diluent and 2-7 parts of crosslinking agent; the modified kaolin is prepared from silane coupling agent, modifier and grafting agent.

2. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 1, characterized in that: The mixed monomer is a mixture of methyl methacrylate, butyl acrylate and isooctyl acrylate.

3. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 1, characterized in that: The preparation method of the modified kaolin comprises the following steps, calculated in parts by weight: S1. Weigh 8-15 parts of kaolin, add 15-35 parts of silane coupling agent hydrolyzate under infrared light, stir evenly, dry, wash with ethanol by centrifugation 1-3 times, and dry to obtain A; S2, weigh 8-15 parts of A in step S1, add 15-30 parts of grafting agent, add 15-35 parts of acetone, ultrasonically disperse, stir evenly under infrared light irradiation, dry, wash with acetone by centrifugation, and dry to obtain B; S3, weigh 8-15 parts of B in step S2, add 30-60 parts of modifier, add 25-50 parts of acetone, ultrasonically disperse, stir evenly under infrared light irradiation, dry, centrifuge wash with acetone, and dry to obtain modified kaolin.

4. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 3, characterized in that: The grafting agent is dodecylbenzene-2,4-diisocyanate.

5. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 3, characterized in that: The modifier is any one of 4-aminononylphosphonic acid, eicosamine, and behenyl primary amine.

6. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 5, characterized in that: The modifier is 4-aminononylphosphonic acid.

7. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 1, characterized in that: The initiator is benzoyl peroxide.

8. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 1, characterized in that: The solvent is ethyl acetate.

9. The waterproof insulating tape of the super soft EPDM rubber substrate as claimed in claim 1, characterized in that: The diluent is xylene; and the cross-linking agent is aziridine.

10. The method for preparing the waterproof insulating tape of the super soft EPDM rubber substrate according to any one of claims 1 to 9, characterized in that: The method comprises the following steps, in parts by weight: Step 1: Evenly mix 30-50 parts of mixed monomers, 5-10 parts of modified kaolin, 1-3 parts of initiator, 1-3 parts of auxiliary agent and 5-20 parts of solvent, heat to reflux, keep warm for 3-4 hours, cool and discharge to obtain a raw material solution; Step 2: Add 40-60 parts of diluent and 2-7 parts of cross-linking agent to the raw material solution in step 1, and stir evenly to obtain a coating solution; Step 3: evenly apply the non-silicone release agent on one side of the EPDM rubber substrate and solidify it, and evenly apply the coating liquid in step 2 on the other side of the EPDM rubber substrate and solidify it to obtain an adhesive layer. After cooling, winding and cutting, a waterproof insulating tape with an ultra-soft EPDM rubber substrate is obtained.

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