Temperature-resistant and moisture-resistant expansion rubber composition and preparation method thereof

Abstract

The invention relates to the technical field of rubber materials, in particular to a temperature-resistant and moisture-resistant expansion rubber composition and a preparation method thereof. The invention provides a temperature-resistant and moisture-resistant expansion rubber composition which comprises the following components in parts by weight: 100 parts of main material rubber, 2-10 parts of an anti-aging agent, 20-35 parts of carbon black, 8-15 parts of a foaming agent, 10-18 parts of a vulcanizing agent, 6-15 parts of protective wax and 2-6 parts of a filling agent, wherein the filling agent is a carbon nano tube and nano calcium carbonate. The temperature-resistant and moisture-resistant expansion rubber composition provided by the invention has excellent temperature and humidity resistance, and after the composition is placed in an environment of 60 DEG C and 95% RH for 2 weeks, the viscosity and the expansion rate of the material can be basically kept unchanged, so that a good filling effect during subsequent use is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber materials, in particular to a temperature and humidity resistant expanded rubber composition and a preparation method thereof. BACKGROUND

[0002] Both the expanded rubber block and the expanded rubber tape belong to expanded rubber products, which have the characteristics of volume expansion through physical or chemical action, so as to realize the sealing and filling of spaces such as gaps or holes. According to the expansion mechanism, they are mainly divided into water-swelling type, heat-swelling type and chemical-swelling type, among which the water-swelling type and the heat-swelling type are more widely used in engineering sealing field. However, the traditional expanded rubber products are prone to self-vulcanization during storage, especially in high temperature and high humidity environment, which leads to the decrease of product adhesion and expansion rate, even cannot foam in actual use, and thus cannot play a good filling effect.

[0003] Therefore, it is urgent to develop an expanded rubber composition with excellent heat resistance and humidity resistance, so that it can be stored stably under high temperature and high humidity conditions and still have good filling effect in subsequent use. SUMMARY

[0004] In view of this, the present application provides a temperature and humidity resistant expanded rubber composition and a preparation method thereof. The expanded rubber composition has excellent temperature and humidity resistance. The adhesion and expansion rate of the material can remain unchanged after being placed in an environment of 60℃ and 95%RH for 2 weeks, which ensures good filling effect in subsequent use.

[0005] The technical scheme of the present application is as follows: The present application provides a temperature and humidity resistant expanded rubber composition, which comprises, in terms of weight fraction: 100 parts of main material rubber, 2-10 parts of antioxidant, 20-35 parts of carbon black, 8-15 parts of foaming agent, 10-18 parts of vulcanizing agent, 6-15 parts of protective wax and 2-6 parts of filler; wherein the filler is carbon nanotube and nano calcium carbonate.

[0006] The application introduces anti-aging agents, carbon black, foaming agents, vulcanizing agents, protective waxes and fillers as fillers into the rubber matrix by optimizing the base formula of the rubber composition, wherein the anti-aging agents can improve the temperature and humidity resistance of the rubber composition system, the carbon black can not only ensure the strength of the rubber, but also improve the fluidity of the composition and ensure good dispersion performance of each component; the foaming agent can ensure the expansion effect of the rubber composition; the addition of the vulcanizing agent can cross-link the main material rubber molecular chains in the rubber composition to form a network structure, thereby providing the obtained expanded rubber product with basic mechanical properties; the protective wax can form a protective film on the surface of the expanded rubber composition to avoid the erosion of moisture in the environment on the expanded rubber composition. In addition, carbon nanotubes and nano calcium carbonate are added as fillers, the carbon nanotubes have good mechanical strength and heat resistance, and can be inserted between the gaps of the main material rubber molecular chains; when the temperature and humidity of the environment where the expanded rubber composition is located increase, the carbon nanotubes can effectively hinder the migration of the rubber molecular chains, thereby avoiding the premature vulcanization of the expanded rubber composition due to the influence of the environment and losing adhesion, and ensuring that it does not affect subsequent use; at the same time, nano calcium carbonate is also added, in actual use, the expanded rubber composition is expanded by heating, at this time, the nano calcium carbonate is dispersed in the gaps of the rubber matrix to promote the sliding of the rubber polymer molecular chains and ensure that the expanded rubber composition has good expansion rate.

[0007] Preferably, the mass ratio of the carbon nanotubes to the nano calcium carbonate is 1:0.2-0.6; and the aspect ratio of the carbon nanotubes is 8-12.

[0008] The mass ratio of the carbon nanotubes to the nano calcium carbonate can not only avoid premature vulcanization of the expanded rubber composition in a humid and hot environment, but also ensure that it has good expansion rate.

[0009] Further preferably, the mass ratio of the carbon nanotubes to the nano calcium carbonate is 1:0.4; and the aspect ratio of the carbon nanotubes is 8-10.

[0010] Preferably, the main material rubber is at least one selected from the group consisting of styrene butadiene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, chlorohydrin rubber, acrylate rubber and silicone rubber.

[0011] The application selects the above main material which is not easy to cross-link and vulcanize in a high temperature and high humidity environment to ensure that the obtained expanded rubber composition does not lose adhesion in a high temperature and high humidity environment.

[0012] Preferably, the anti-aging agent is at least one selected from the group consisting of phenolic anti-aging agents, amine anti-aging agents and heterocyclic anti-aging agents.

[0013] The above anti-aging agent has good temperature and humidity resistance, and its single use or multiple use can improve the temperature and humidity resistance of the formula system.

[0014] Further preferably, the phenolic antioxidant can be antioxidant 1010 or antioxidant 1076, the amine antioxidant can be antioxidant 4020 or antioxidant 4010, and the heterocyclic antioxidant can be antioxidant MB or antioxidant RD.

[0015] Preferably, the carbon black has a particle size of 10-30 nm and 80-100 nm.

[0016] Further preferably, the carbon black can be carbon black 110, carbon black 220 or carbon black 330.

[0017] Preferably, the mass ratio of the carbon black with a particle size of 10-30 nm to the carbon black with a particle size of 80-100 nm is 1:2-4.

[0018] The present application ensures good dispersion performance while ensuring the strength of the rubber compound by adding carbon black with different particle sizes.

[0019] Preferably, the blowing agent is a mixture of organic blowing agent and microsphere blowing agent with a mass ratio of 1:0.2-0.8.

[0020] The microsphere blowing agent is a blowing agent that can rapidly expand and increase in volume to tens of times its own size after heating, and has the advantages of stable performance, non-flammability, non-pollution, non-toxicity, non-odor, non-corrosion to the mold, and no dyeing to the product. The present application selects a blowing agent with a higher decomposition temperature, which can avoid premature decomposition of the blowing agent due to temperature changes during the storage of the expanded composition. The use of organic blowing agent and microsphere blowing agent together can not only improve the stability of the expanded composition during storage, but also provide good expansion rate and expansion effect.

[0021] Further preferably, the organic blowing agent can be azodicarbonamide, p-toluene hydrazine, or dinitrosopentamethylene tetramine.

[0022] Preferably, the vulcanizing agent is selected from one or more of thiazoles, sulfenamides and guanidine vulcanizing agents.

[0023] The above-mentioned vulcanizing agent belongs to a slow vulcanization system, which can slow down the vulcanization speed and avoid the early scorching phenomenon of the expanded rubber composition.

[0024] Further preferably, the vulcanizing agent can be any one of 2-mercaptobenzothiazole, diphenyl disulfide, N,N-diisopropyl-2-benzothiazole sulfenamide, di-o-tolyl guanidine or o-tolyl biguanide.

[0025] Preferably, the protective wax has a C20-C23 content of 22.0wt%-35.0wt%, a C24-C26 content of 10.0wt%-15.0wt%, a C27-C30 content of 30.0wt%-40.0wt%, and a C31-C35 content of 25.0wt%-35.0wt%.

[0026] The present application selects protective wax / wax materials with various solubilities in rubber, uses the blooming characteristics of the wax to form a protective film on the surface of the expanded rubber composition, and avoids the erosion of moisture on the rubber. By using protective waxes with different carbon numbers, the solubility and migration are balanced, and the protective effect is better.

[0027] The present application also provides a preparation method of the above-mentioned temperature-resistant and moisture-resistant expanded rubber composition, and the steps include: The main material rubber is added to an open mill, and low-temperature plasticizing is performed at 55-70 DEG C for 10-15 minutes, and then the temperature is raised to 90-105 DEG C for plasticizing for 20-30 minutes, to obtain the plasticized main material rubber; The anti-aging agent, carbon black, foaming agent, vulcanizing agent, protective wax, and filler are added to the plasticized main material rubber, and sufficient mixing is performed below 50 DEG C, to obtain the temperature-resistant and moisture-resistant expanded rubber composition.

[0028] The preparation method provided by the present application first performs low-temperature plasticizing and high-temperature plasticizing on the main material rubber respectively, the sufficient plasticizing of the main material rubber can make it reach greater plasticity, and then the main material rubber has lower Mooney viscosity and is more easily mixed with other fillers; then the anti-aging agent, carbon black, foaming agent, vulcanizing agent, protective wax, and filler are added to the plasticized main material rubber, and sufficient mixing is performed at a lower temperature, to ensure that various materials are sufficiently mixed and dispersed uniformly.

[0029] The present application also provides an expanded rubber block or expanded rubber tape, which is prepared by using the above-mentioned temperature-resistant and moisture-resistant expanded rubber composition or the temperature-resistant and moisture-resistant expanded rubber composition prepared according to the above-mentioned preparation method as raw materials.

[0030] In actual application, the expanded rubber block or expanded rubber tape is subjected to electrophoretic baking, and the expanded rubber block / tape is crosslinked, vulcanized, expanded, and foamed in this process.

[0031] Compared with the prior art, the application has the beneficial effects that the application significantly improves the temperature and humidity resistance and structural stability during the expansion process of the expanded rubber composition through specific selection of the formula, and the temperature and humidity resistance of the expanded rubber composition is tested, which can be placed in an environment of 60 DEG C, 95% RH for 2 weeks without changing the viscosity and expansion ratio, solving the practical problem that the existing expanded rubber cannot be produced in large quantities in advance and stored due to environmental changes. For the production department, more rubber (i.e. expanded rubber composition) can be produced at one time, reducing production waste, and the rubber will not be scrapped due to long storage time, saving production cost; secondly, the products extruded by the rubber can also be stored, so as to meet the customer demand in time; thirdly, when the expanded rubber composition is stored as a transaction product in the customer's warehouse, it will not cause insufficient viscosity and reduced expansion rate of the product due to the harsh storage environment, ensuring the product quality, improving the customer satisfaction, reducing the loss of the production enterprise caused by the customer's return and exchange, and having great practical significance and economic value. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with specific examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0033] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as that generally understood by those skilled in the art to which the present application belongs. It should also be understood that terms such as those defined in a general dictionary should be understood as having meanings consistent with those in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0034] Unless otherwise specified, the equipment, reagents and raw materials used in the following examples and comparative examples of the present application are all conventional commercially available products in the art.

[0035] At present, the expanded rubber block / belt product is produced by the supplier, that is, the non-vulcanized rubber composition is sent to the client warehouse, and the client extracts the goods for use according to the production schedule. In actual use, the client lays the product on the sheet metal, and then the expanded rubber block / belt is crosslinked and vulcanized and expanded and foamed in the process of electrophoretic baking. However, the client warehouse is a conventional warehouse, and the storage environment is relatively poor. The temperature and humidity are greatly affected by the weather, especially in summer. The temperature and humidity in the warehouse are very high, which is not conducive to the storage of the expanded rubber block / belt (the expanded rubber block / belt is best stored in a dry environment at 23 DEG C). The expanded rubber block / belt is easy to vulcanize itself in this environment, resulting in loss of adhesion of the product itself during storage. When used, the product is not well bonded to the sheet metal and is easy to fall off. At the same time, the product expansion rate is reduced, and even foaming is not possible, resulting in the inability to fill the cavity.

[0036] The temperature-resistant and humidity-resistant expanded rubber composition provided by the application can be placed in an environment of 60 DEG C and 95% RH for 2 weeks without changing the adhesion and expansion rate, solving the actual problem that the existing expanded rubber cannot be produced and stored in large quantities in advance due to environmental changes.

[0037] Example 1 The temperature-resistant and humidity-resistant expanded rubber composition provided by the application can be placed in an environment of 60 DEG C and 95% RH for 2 weeks without changing the adhesion and expansion rate, solving the actual problem that the existing expanded rubber cannot be produced and stored in large quantities in advance due to environmental changes.

[0038] Example 2 The temperature-resistant and humidity-resistant expanded rubber composition provided by the application can be placed in an environment of 60 DEG C and 95% RH for 2 weeks without changing the adhesion and expansion rate, solving the actual problem that the existing expanded rubber cannot be produced and stored in large quantities in advance due to environmental changes.

[0039] Example 3 The embodiment provides a temperature and moisture resistant swelling rubber composition, which comprises, according to parts by weight: 100 parts of main material rubber (20 parts of styrene-butadiene rubber, 20 parts of acrylate rubber, 20 parts of silicone rubber and 40 parts of butyl rubber), 4 parts of antioxidant (2 parts of antioxidant 4010 and 2 parts of antioxidant MB), 35 parts of carbon black (10 parts of carbon black with a particle size of 10-30 nm and 25 parts of carbon black with a particle size of 80-100 nm), 15 parts of foaming agent (10 parts of dinitrosopentamethylene tetramine and 5 parts of microsphere foaming agent), 10 parts of vulcanizing agent (N, N-diisopropyl-2-benzothiazole sulfenamide), 14 parts of protective wax and 2.5 parts of filler (2 parts of carbon nanotube with a length-diameter ratio of 8-12 and 0.5 part of nano calcium carbonate).

[0040] Example 4 The embodiment provides a preparation method of the temperature and moisture resistant swelling rubber composition in the embodiment 1, and the steps comprise the following: according to the formula composition in the embodiment 1, the main material rubber is added into an open mill, and is plasticized at a low temperature of 62 DEG C for 12 minutes, then is plasticized at a high temperature of 98 DEG C for 25 minutes, so that the plasticized main material rubber is obtained; the antioxidant, the carbon black, the foaming agent, the vulcanizing agent, the protective wax and the filler are added into the plasticized main material rubber, and are fully mixed at 40 DEG C, so that the temperature and moisture resistant swelling rubber composition is obtained.

[0041] Example 5 The embodiment provides a preparation method of the temperature and moisture resistant swelling rubber composition in the embodiment 2, and the steps comprise the following: according to the formula composition in the embodiment 2, the main material rubber is added into an open mill, and is plasticized at a low temperature of 56 DEG C for 15 minutes, then is plasticized at a high temperature of 90 DEG C for 30 minutes, so that the plasticized main material rubber is obtained; the antioxidant, the carbon black, the foaming agent, the vulcanizing agent, the protective wax and the filler are added into the plasticized main material rubber, and are fully mixed at 45 DEG C, so that the temperature and moisture resistant swelling rubber composition is obtained.

[0042] Example 6 The embodiment provides a preparation method of the temperature and moisture resistant swelling rubber composition in the embodiment 3, and the steps comprise the following: according to the formula composition in the embodiment 3, the main material rubber is added into an open mill, and is plasticized at a low temperature of 70 DEG C for 10 minutes, then is plasticized at a high temperature of 105 DEG C for 20 minutes, so that the plasticized main material rubber is obtained; the antioxidant, the carbon black, the foaming agent, the vulcanizing agent, the protective wax and the filler are added into the plasticized main material rubber, and are fully mixed at 30 DEG C, so that the temperature and moisture resistant swelling rubber composition is obtained.

[0043] Comparative Example 1 The comparative example provides a temperature and humidity resistant expanded rubber composition, which comprises, in parts by weight: 100 parts of main material rubber (50 parts of styrene-butadiene rubber, 20 parts of butyl rubber, and 30 parts of chlorohydrate rubber), 6 parts of antioxidant (3 parts of antioxidant 1010 and 3 parts of antioxidant 4020), 28 parts of carbon black (8 parts of carbon black with a particle size of 10-30 nm and 20 parts of carbon black with a particle size of 80-100 nm), 12 parts of foaming agent (8 parts of azodicarbonamide and 4 parts of microsphere foaming agent), 15 parts of vulcanizing agent (2-mercaptobenzothiazole), and 11 parts of protective wax.

[0044] The comparative example is different from the formulation of example 1 in that no filler is added, and the rest of the components and amounts are the same as in example 1.

[0045] Comparative example 2 The comparative example provides a temperature and humidity resistant expanded rubber composition, which comprises, in parts by weight: 100 parts of main material rubber (50 parts of styrene-butadiene rubber, 20 parts of butyl rubber, and 30 parts of chlorohydrate rubber), 6 parts of antioxidant (3 parts of antioxidant 1010 and 3 parts of antioxidant 4020), 28 parts of carbon black (8 parts of carbon black with a particle size of 10-30 nm and 20 parts of carbon black with a particle size of 80-100 nm), 12 parts of foaming agent (8 parts of azodicarbonamide and 4 parts of microsphere foaming agent), 15 parts of vulcanizing agent (2-mercaptobenzothiazole), and 11 parts of protective wax, and 4 parts of filler (4 parts of carbon nanotube with an aspect ratio of 8-10).

[0046] The comparative example is different from the formulation of example 1 in that the filler is only carbon nanotube and no nano calcium carbonate is added, and the rest of the components and amounts are the same as in example 1.

[0047] Test example The temperature and humidity resistant expanded rubber compositions obtained in examples 1-3 and comparative examples 1-2 were used as raw materials to prepare expanded rubber blocks, and the adhesion (the rubber blocks were respectively laid on sheet metal and left to stand at room temperature for 1 week, and the falling-off situation was observed) and expansion rate (the expanded rubber blocks were laid on sheet metal, and the expansion rate was tested after electrophoretic baking) of the expanded rubber blocks prepared from examples 1-3 and comparative examples 1-2 were tested. Then, the temperature and humidity resistance test was carried out: another rubber block was taken, and the rubber block was placed in a constant temperature and humidity phase (simulating a high temperature and high humidity environment) with a temperature of 60°C and a humidity of 95% RH for 2 weeks, and then the adhesion and expansion rate were tested again (expansion rate (%) = (expanded volume-initial volume) / initial volume x 100%). The test results are shown in Table 1.

[0048] Table 1

[0049] As shown in Table 1, compared with Example 1, when no carbon nanotubes or no filler is added, the adhesion and expansion rate of the obtained expanded rubber composition is significantly worse after being placed in a high temperature and high humidity environment for 2 weeks, and the adhesion between the expanded rubber composition and the sheet metal and the expansion rate thereof are significantly worse, which indicates that the temperature and humidity resistant expanded rubber composition provided by the application has good structural stability, and the adhesion and expansion rate thereof almost do not change after being stored in a high temperature and high humidity environment for 2 weeks.

[0050] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A heat-resistant and moisture-resistant expandable rubber composition, characterized in that: In parts by weight, comprising: Main material rubber 100 parts, antioxidant 2-10 parts, carbon black 20-35 parts, foaming agent 8-15 parts, vulcanizing agent 10-18 parts, protective wax 6-15 parts, filler 2-6 parts; Wherein, the filler is carbon nanotube and nano calcium carbonate.

2. The heat-resistant and moisture-resistant expandable rubber composition according to claim 1, wherein The mass ratio of the carbon nanotubes to nano-calcium carbonate is 1:0.2-0.6; and the aspect ratio of the carbon nanotubes is 8-12.

3. The heat-resistant and moisture-resistant expandable rubber composition according to claim 1, wherein The main rubber is selected from at least one of styrene-butadiene rubber, acrylonitrile-butadiene rubber, butyl rubber, EPDM rubber, epichlorohydrin rubber, acrylic rubber and silicone rubber.

4. The heat-resistant and moisture-resistant expandable rubber composition according to claim 1, wherein The antioxidant is at least one of a phenolic antioxidant, an amine antioxidant and a heterocyclic antioxidant.

5. The heat-resistant and moisture-resistant expandable rubber composition according to claim 1, wherein: The particle size of the carbon black is 10-30 nm and 80-100 nm.

6. The heat-resistant and moisture-resistant expandable rubber composition according to claim 5, characterized in that: The mass ratio of carbon black with a particle size of 10-30 nm to carbon black with a particle size of 80-100 nm is 1:2-4.

7. The heat-resistant and moisture-resistant expandable rubber composition according to claim 1, wherein The foaming agent is a mixture of an organic foaming agent and a microsphere foaming agent in a mass ratio of 1:0.2-0.

8.

8. The heat-resistant and moisture-resistant expandable rubber composition according to claim 1, wherein The vulcanizing agent is selected from one or more of thiazole, sulfenamide and guanidine vulcanizing agents.

9. A method for preparing the heat-resistant and moisture-resistant expansive rubber composition according to any one of claims 1 to 8, characterized in that the steps include: Add the main rubber material into an open mill, and plasticize at a low temperature of 55-70° C. for 10-15 minutes, then increase the temperature to 90-105° C. and plasticize for 20-30 minutes to obtain the plasticized main rubber material; The antioxidant, carbon black, foaming agent, vulcanizing agent, protective wax and filler are added to the plasticized main rubber and fully mixed at a temperature below 50° C. to obtain the heat-resistant and moisture-resistant expansive rubber composition.

10. An expandable rubber block or expandable tape, characterized in that: The heat-resistant and moisture-resistant expansive rubber composition is prepared using the heat-resistant and moisture-resistant expansive rubber composition according to any one of claims 1 to 8 or the heat-resistant and moisture-resistant expansive rubber composition prepared according to the preparation method according to claim 9 as raw materials.

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