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 belongs to the technical field of polymer adhesives. The invention discloses an adhesive for bonding fluororubber and a fluorine-containing inert material, which is prepared by adopting a method of bulk polymerization of a silane coupling agent and vinyl-terminated fluorosilicone oil. According to the adhesive, the fluororubber and the fluorine-containing inert material can achieve excellent bonding strength, and the adhesive is simple in preparation process, low in price, easy to operate and easy to industrialize and has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer adhesives, and particularly relates to an adhesive and its preparation method and uses. Background Art

[0002] Fluororubber is a synthetic polymer elastomer in which fluorine atoms are contained in the carbon atoms of the main chain or side chains, and has many excellent properties. It has excellent high-temperature resistance and can maintain good elasticity and sealing performance in a relatively wide high-temperature range (generally up to 200°C - 250°C or even higher), and can withstand the thermal oxidation in a high-temperature environment for a long time; it has strong chemical stability and has good tolerance to various chemical media such as fuel oil, lubricating oil, strong acids and bases, and is not prone to chemical reactions resulting in performance deterioration. Therefore, it is widely used in the fields of aerospace, automotive manufacturing, petrochemical industry, etc.

[0003] In some complex industrial application scenarios and advanced technology products, it is often necessary to combine fluororubber with fluorine-containing inert materials. For example, in the new energy vehicle battery system, the PVDF (polyvinylidene fluoride) diaphragm and the fluororubber sealing structure need to be tightly connected to ensure the sealing and safety of the battery; in special devices for chemical production, the pipes or containers made of PTFE (polytetrafluoroethylene) and the sealing and connecting parts of fluororubber also need reliable bonding to prevent medium leakage and ensure the normal operation of the device. Therefore, achieving good and stable bonding between fluororubber and fluorine-containing inert materials has become an urgent need in practical applications.

[0004] Chinese Patent Application CN112341956A discloses a heat-curable adhesive for fluororubber oil seals and its preparation method. The adhesive prepared in this patent needs to be melted at high temperature and then cooled and ground into powder, and then dispersed in a mixed solution of ethanol and silane coupling agent. Chinese Patent CN106632901B discloses a preparation method for an adhesive for untreated fluorine-containing materials. This method is based on the reaction of hydroxyl-terminated fluororubber and isocyanatoethyl methacrylate under the catalysis of dibutyltin dilaurate to form a fluororubber macromonomer, and then through free radical polymerization with acrylate to form a graft polymer. These existing technologies have complex preparation processes, high costs and cannot meet the requirements of environmental friendliness.

[0005] The bonding interface formed by the existing bonding method between fluororubber and fluorine-containing inert materials has a weak bonding force. Under the action of external forces such as a certain tensile force and shear force, debonding is likely to occur. Moreover, many adhesives will soften, flow, or undergo cohesive failure in a high-temperature environment, resulting in bonding failure and unable to meet the bonding requirements of the two under high-temperature working conditions. For some special adhesives that can achieve a certain bonding effect, their synthesis process is complex, requiring harsh reaction conditions and multiple cumbersome preparation procedures, resulting in low production efficiency and high production costs, restricting their large-scale industrial applications. And when in use, it may also require special and complex coating operation processes, further increasing the use cost and application difficulty.

[0006] There is an urgent need to develop an adhesive for fluororubber and fluorine-containing inert materials with a simple preparation method, low cost, and convenient use. Summary of the Invention

[0007] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide an adhesive and its preparation method and uses.

[0008] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0009] The present invention provides an adhesive, which is prepared from an initiator, a terminal vinyl fluorosilicone oil, and a silane coupling agent as raw materials, and the molar ratio of the initiator, the silane coupling agent, and the terminal vinyl fluorosilicone oil is 1:(10 - 120):(60 - 240).

[0010] Further, the molar ratio of the initiator, the silane coupling agent, and the terminal vinyl fluorosilicone oil is 1:(40 - 80):(120 - 160); the initiator is at least one of azobisisobutyronitrile, benzoyl peroxide, and diisopropylbenzene peroxide.

[0011] Further, the molar ratio of the initiator, the silane coupling agent, and the terminal vinyl fluorosilicone oil is 1:40:160, 1:60:140, or 1:80:120; the initiator is azobisisobutyronitrile.

[0012] The present invention also provides a preparation method of the above adhesive, and the preparation method is to uniformly mix the initiator, the silane coupling agent, and the terminal vinyl fluorosilicone oil, and react to obtain it.

[0013] Further, the reaction conditions are under the protection of an inert medium, and the reaction temperature is 40 - 120 °C.

[0014] Further, the inert medium is nitrogen, and the reaction temperature is 80 °C.

[0015] The present invention also provides the use of the above adhesive for bonding fluororubber and fluorine-containing inert materials.

[0016] Further, the fluororubber is peroxide fluororubber, and the fluorine-containing material is polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer or polytetrafluoroethylene.

[0017] The present invention also provides a fluorine-containing composite material, which is prepared from a fluororubber masterbatch and a fluorine-containing material as raw materials;

[0018] The fluororubber masterbatch is obtained by kneading peroxide fluororubber raw rubber, an acid absorbent, a filler, a vulcanizing agent, a vulcanization accelerator and the above-mentioned adhesive, standing, and re-kneading.

[0019] The mass ratio of the peroxide fluororubber raw rubber, the acid absorbent, the filler, the vulcanizing agent, the vulcanization accelerator and the above-mentioned adhesive is (50-200):(1-10):(10-50):(0.1-5):(0.1-5):(0.1-5).

[0020] Further, the kneading time is 1-10 min, the standing time is 10-50 h, and the re-kneading is thin-pass 1-15 times;

[0021] The acid absorbent is zinc oxide, the filler is at least one of barium sulfate, calcium silicate, carbon black, diatomaceous earth, silica powder and white carbon black, the vulcanizing agent is 2,5-di-tert-butylperoxy-2,5-dimethylhexane, and the vulcanization accelerator is triallyl isocyanurate;

[0022] The mass ratio of the peroxide fluororubber raw rubber, the acid absorbent, the filler, the vulcanizing agent, the vulcanization accelerator and the above-mentioned adhesive is 100:3:25:1.5:1:1.

[0023] Further, the kneading time is 2 min, the standing time is 24 h, and the re-kneading is thin-pass 8 times.

[0024] The present invention also provides a preparation method of the above-mentioned fluorine-containing composite material, which is to bond the fluororubber masterbatch and the fluorine-containing material to obtain the fluorine-containing composite material.

[0025] Further, the bonding is by hot pressing, the temperature of the hot pressing is 50-300 °C, and the time of the hot pressing is 30-150 min.

[0026] Further, the temperature of the hot pressing is 150 °C, and the time of the hot pressing is 60 min.

[0027] The present invention has achieved the following beneficial effects:

[0028] The present invention prepares an adhesive for bonding fluororubber and fluorine-containing inert materials by the method of bulk polymerization of silane coupling agent and vinyl-terminated fluorosilicone oil. This adhesive can achieve excellent bonding strength between fluororubber and fluorine-containing inert materials, and has a simple preparation process, low price, easy operation, and is easy to industrialize, showing good application prospects.

[0029] Obviously, based on the above content of the present invention, according to the common general technical knowledge and conventional means in the art, without departing from the above basic technical idea of the present invention, various other forms of modification, substitution or change can be made.

[0030] The following further detailed description of the above content of the present invention is given through specific embodiments in the form of examples. However, this should not be construed as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention fall within the scope of the present invention. Specific Embodiments

[0031] The raw materials and equipment used in the present invention are all known products obtained by purchasing commercially available products.

[0032] In the following experiments, if the temperature is not specified, the reaction is carried out under normal temperature conditions. Normal temperature means room temperature, which is 25 ± 5 °C.

[0033] The parts in the embodiments of the present invention are all mole parts.

[0034] The parts in the experimental examples of the present invention are all mass parts.

[0035] The preparation method of the adhesive of the present invention is as follows:

[0036]

[0037] Among them, R1 is an alkyl chain with 1 - 12 carbon atoms, R2 is an alkyl chain with 1 - 2 carbon atoms, R3 is an alkyl chain with a Si atom in the main chain and F atoms in the side chain, and the range of n is an integer from 5 to 10.

[0038] Example 1: Preparation of Adhesive Ⅰ

[0039] Add 20 parts of vinyl-terminated fluorosilicone oil, 80 parts of silane coupling agent and 0.5 part of azobisisobutyronitrile (AIBN) into a three-necked reaction flask. While stirring, introduce nitrogen gas. After the azobisisobutyronitrile is fully dissolved, start heating to 80 °C. After reacting for 6 h, carry out vacuum drying to remove unreacted substances, and obtain Adhesive Ⅰ for bonding fluororubber and fluorine-containing inert materials.

[0040] The above-mentioned vinyl-terminated fluorosilicone oil is vinyl-terminated polymethyltrifluoropropylsiloxane (purchased from Wuhan Lana White Pharmaceutical Chemical Co., Ltd., product number lnb-1193), and the silane coupling agent is allyltrimethoxysilane (purchased from Sigma, CAS number: 2551-83-9).

[0041] Example 2: Preparation of Adhesive II

[0042] Referring to the preparation method of Example 1, the difference is only that 20 parts of vinyl-terminated fluorosilicone oil and 80 parts of silane coupling agent are replaced with 30 parts of vinyl-terminated fluorosilicone oil and 70 parts of silane coupling agent, and Adhesive II for bonding fluororubber and fluorine-containing inert materials is prepared.

[0043] Example 3: Preparation of Adhesive III

[0044] Referring to the preparation method of Example 1, the difference is only that 20 parts of vinyl-terminated fluorosilicone oil and 80 parts of silane coupling agent are replaced with 40 parts of vinyl-terminated fluorosilicone oil and 60 parts of silane coupling agent, and Adhesive III for bonding fluororubber and fluorine-containing inert materials is prepared.

[0045] Example 4: Preparation of Adhesive IV

[0046] Referring to the preparation method of Example 1, the difference is only that 20 parts of vinyl-terminated fluorosilicone oil and 80 parts of silane coupling agent are replaced with 100 parts of silane coupling agent, and Adhesive IV for bonding fluororubber and fluorine-containing inert materials is prepared.

[0047] Example 5: Preparation of Adhesive V

[0048] Referring to the preparation method of Example 1, the difference is only that 20 parts of vinyl-terminated fluorosilicone oil and 80 parts of silane coupling agent are replaced with 100 parts of vinyl-terminated fluorosilicone oil, and Adhesive V for bonding fluororubber and fluorine-containing inert materials is prepared.

[0049] Example 6: Preparation of Adhesive VI

[0050] Referring to the preparation method of Example 1, the difference is only that 20 parts of vinyl-terminated fluorosilicone oil and 80 parts of silane coupling agent are replaced with 60 parts of vinyl-terminated fluorosilicone oil and 40 parts of silane coupling agent, and Adhesive VI for bonding fluororubber and fluorine-containing inert materials is prepared.

[0051] Example 7: Preparation of Adhesive VII

[0052] Referring to the preparation method of Example 1, the difference is only that 20 parts of vinyl-terminated fluorosilicone oil and 80 parts of silane coupling agent are replaced with 10 parts of vinyl-terminated fluorosilicone oil and 90 parts of silane coupling agent, and Adhesive VII for bonding fluororubber and fluorine-containing inert materials is prepared.

[0053] The beneficial effects of the present invention are demonstrated by the following experimental examples.

[0054] Experimental Example 1: Adhesion strength test of the fluorine-containing composite material of the present invention

[0055] Each fluorine-containing composite material to be tested was prepared according to the following method, and the adhesion strength was tested according to GB / T 532-2008:

[0056] 1. Preparation of peroxide fluororubber masterbatch: The peroxide fluororubber raw rubber, acid absorbent, filler, vulcanizing agent, vulcanization accelerator and the adhesive obtained according to the preparation method of the above-mentioned embodiment were added to a mixer and kneaded for 120 s, then left to stand at room temperature for 24 hours, and then remilled on an open mill. The remilling process was thin pass 8 times, and the sheet was taken off to prepare a peroxide fluororubber masterbatch. The acid absorbent was zinc oxide, the filler was carbon black (the filler can be replaced by at least one of barium sulfate, calcium silicate, carbon black, diatomaceous earth, silica powder and white carbon black), the vulcanizing agent was 2,5-di-tert-butylperoxy-2,5-dimethylhexane, and the vulcanization accelerator was triallyl isocyanurate.

[0057] 2. Preparation of fluorine-containing composite material: The peroxide fluororubber masterbatch was bonded to the fluorine-containing inert material PVDF by hot pressing (temperature 150 °C, time 60 min) to obtain a fluorine-containing composite material.

[0058] The following are the specific preparation methods of each fluorine-containing composite material to be tested and the results obtained by testing according to GB / T 532-2008:

[0059] Test 1: 100 parts of peroxide fluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, and 1 part of vulcanization accelerator were taken according to the formula in the above test method to prepare peroxide fluororubber masterbatch A. The peroxide fluororubber masterbatch A was bonded to PVDF by hot pressing to obtain fluorine-containing composite material 1. According to GB / T 532-2008, the peel strength was measured to be 0.16.

[0060] Test 2: 100 parts of peroxide fluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, 1 part of vulcanization accelerator, and 1 part of adhesive I obtained in Example 1 were taken according to the formula in the above test method to prepare peroxide fluororubber masterbatch B. The peroxide fluororubber masterbatch B was bonded to PVDF by hot pressing to obtain fluorine-containing composite material 2. According to GB / T 532-2008, the failure mode was found to be internal failure of the rubber.

[0061] Test 3: Take 100 parts of peroxyfluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, 1 part of vulcanization accelerator, and 1 part of Adhesive Ⅱ obtained in Example 2 according to the formula in the above test method to prepare peroxyfluororubber compound C. Bond the peroxyfluororubber compound C and PVDF by hot pressing to obtain fluorine-containing composite material 3. According to GB / T 532-2008, the failure mode was found to be internal rubber failure.

[0062] Test 4: Take 100 parts of peroxyfluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, 1 part of vulcanization accelerator, and 1 part of Adhesive Ⅲ obtained in Example 3 according to the formula in the above test method to prepare peroxyfluororubber compound D. Bond the peroxyfluororubber compound D and PVDF by hot pressing to obtain fluorine-containing composite material 4. According to GB / T 532-2008, the failure mode was found to be internal rubber failure.

[0063] Test 5: Take 100 parts of peroxyfluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, 1 part of vulcanization accelerator, and 1 part of Adhesive Ⅳ obtained in Example 4 according to the formula in the above test method to prepare peroxyfluororubber compound D. Bond the peroxyfluororubber compound D and PVDF by hot pressing to obtain fluorine-containing composite material 5. According to GB / T 532-2008, the peel strength was measured to be 0.35.

[0064] Test 6: Take 100 parts of peroxyfluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, 1 part of vulcanization accelerator, and 1 part of Adhesive Ⅴ obtained in Example 5 according to the formula in the above test method to prepare peroxyfluororubber compound D. Bond the peroxyfluororubber compound D and PVDF by hot pressing to obtain fluorine-containing composite material 6. According to GB / T 532-2008, the peel strength was measured to be 0.21.

[0065] Test 7: Take 100 parts of peroxyfluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, 1 part of vulcanization accelerator, and 1 part of Adhesive Ⅵ obtained in Example 6 according to the formula in the above test method to prepare peroxyfluororubber compound D. Bond the peroxyfluororubber compound D and PVDF by hot pressing to obtain fluorine-containing composite material 7. According to GB / T 532-2008, the peel strength was measured to be 0.32.

[0066] Test 8: Take 100 parts of peroxyfluororubber raw rubber, 3 parts of acid absorbent, 25 parts of filler, 1.5 parts of vulcanizing agent, 1 part of vulcanization accelerator, and 1 part of adhesive VII obtained in Example 7 according to the formula in the above test method to prepare peroxyfluororubber compound D. Bond the peroxyfluororubber compound D and PVDF by hot pressing to obtain fluorine-containing composite material 8. According to GB / T 532-2008, the measured peel strength is 0.37.

[0067] As is well known to those skilled in the art, the greater the peel strength, the greater the bonding strength; the bonding strength of the internal failure mode is better than that of the peel failure mode. The above experimental results show that compared with not using the adhesive, the bonding strength of the fluorine-containing composite material prepared with the adhesive of the present invention is significantly improved. Further comparison shows that compared with the adhesives IV, V, VI, and VII of the present invention, the failure modes of the fluorine-containing composite materials prepared with the adhesives I, II, and III of the present invention are all internal rubber failures, indicating that the effects of using the adhesives I, II, and III of the present invention are the best.

[0068] In summary, the present invention prepares an adhesive for bonding fluororubber and fluorine-containing inert materials by the method of bulk polymerization of silane coupling agent and vinyl-terminated fluorosilicone oil. The adhesive can achieve excellent bonding strength between fluororubber and fluorine-containing inert materials, and has a simple preparation process, low price, easy operation, and easy industrialization, and has good application prospects.

Claims

1. An adhesive, characterized in that: The adhesive is prepared by using an initiator, vinyl-terminated fluorosilicone oil and a silane coupling agent as raw materials, and the molar ratio of the initiator, the silane coupling agent and the vinyl-terminated fluorosilicone oil is 1:(10-120):(60-240).

2. The adhesive according to claim 1, characterized in that: The molar ratio of the initiator, the silane coupling agent and the vinyl-terminated fluorosilicone oil is 1:(40-80):(120-160); the initiator is at least one of azobisisobutyronitrile, dibenzoyl peroxide and diisopropylbenzene peroxide.

3. The adhesive according to claim 2, characterized in that: The molar ratio of the initiator, the silane coupling agent and the vinyl-terminated fluorosilicone oil is 1:40:160, 1:60:140 or 1:80:120; and the initiator is azobisisobutyronitrile.

4. The method for preparing the adhesive according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: uniformly mixing an initiator, a silane coupling agent and vinyl-terminated fluorosilicone oil, and reacting the mixture to obtain the product.

5. The preparation method according to claim 4, characterized in that: The reaction condition is inert medium protection, and the reaction temperature is 40-120°C; preferably, the inert medium is nitrogen, and the reaction temperature is 80°C.

6. Use of the adhesive according to any one of claims 1 to 3 for bonding fluororubber and fluorine-containing inert materials.

7. The use according to claim 6, characterized in that: The fluororubber is peroxide fluororubber, and the fluorine-containing material is polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer or polytetrafluoroethylene.

8. A fluorine-containing composite material, characterized in that: The fluorine-containing composite material is prepared by using fluorine rubber compound and fluorine-containing material as raw materials; The fluororubber compound is obtained by mixing peroxide fluororubber raw rubber, an acid absorber, a filler, a vulcanizing agent, a vulcanization accelerator and the adhesive according to any one of claims 1 to 3, stopping, and re-mixing to obtain the fluororubber compound; The mass ratio of the fluororubber raw rubber, acid absorbent, filler, vulcanizing agent, vulcanization accelerator and the adhesive according to any one of claims 1 to 3 is (50-200):(1-10):(10-50):(0.1-5):(0.1-5): (0.1～5)。 9. The fluorine-containing composite material according to claim 8, characterized in that: The mixing time is 1 to 10 minutes, the parking time is 10 to 50 hours, and the re-milling is 1 to 15 times of thinning; The acid absorber is zinc oxide, the filler is at least one of barium sulfate, calcium silicate, carbon black, diatomaceous earth, silicon powder and white carbon black, the vulcanizing agent is 2,5-di-tert-butyl peroxide-2,5-dimethylethane, and the vulcanization accelerator is triallyl isocyanurate; The mass ratio of the fluororubber raw rubber, acid absorber, filler, vulcanizer, vulcanization accelerator and the adhesive according to any one of claims 1 to 3 is 100:3:25:1.5:1:1; preferably, the mixing time is 2 minutes, the parking time is 24 hours, and the re-milling is 8 times of thin pass.

10. The method for preparing the fluorine-containing composite material according to claim 8 or 9, characterized in that: The preparation method comprises bonding a fluororubber compound with a fluorine-containing material to obtain a fluorine-containing composite material; preferably, the bonding is performed by hot pressing, the temperature of the hot pressing is 50 to 300° C., and the time of the hot pressing is 30 to 150 minutes; more preferably, the temperature of the hot pressing is 150° C., and the time of the hot pressing is 60 minutes.

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