A wear-resistant hydrophobic liquid silicone rubber and its preparation method

Abstract

This application relates to the technical field of silicone rubber, and specifically discloses a wear-resistant and hydrophobic liquid silicone rubber and a preparation method thereof. A wear-resistant and hydrophobic liquid silicone rubber includes component A and component B. The formula of component A by weight contains the following raw materials: 80-100 parts of base rubber; 6-18 parts of vinyl silicone oil; 0.5-0.9 parts of platinum catalyst; The formula of component B by weight contains the following raw materials: 70-90 parts of vinyl silicone oil; 17-30 parts of hydrogen-containing silicone oil; 10-19 parts of perfluorooctyl ethylene; 15-25 parts of trimethoxyhydroxysilane; 10-25 parts of steel slag; 0.15-0.65 parts of inhibitor; Component A and component B are mixed in a certain proportion. The wear-resistant and hydrophobic liquid silicone rubber of this application has the advantages of improving the wear resistance and hydrophobicity of liquid silicone rubber.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone rubber, and in particular to a wear-resistant and hydrophobic liquid silicone rubber and a preparation method thereof. Background Art

[0002] Liquid silicone rubber, also known as two-component addition-curing silicone rubber, can be vulcanized at room temperature, and cross-linking reaction can occur between two compounds. This kind of rubber has good fluidity, fast vulcanization speed, can be cast or injection molded, and its performance can be improved by adding appropriate additives. Therefore, liquid silicone rubber is widely used in textile, electronics, decoration and other fields.

[0003] At present, for addition-curing liquid silicone rubber, since the silicone rubber molecular chain is extremely flexible and non-polar, and the intermolecular force is relatively small, the strength of the un-reinforced silicone rubber is very low and has no use value. Therefore, the wear resistance and mechanical properties of silicone rubber are poor, and its application is restricted. There is an urgent need to develop a liquid silicone rubber with good wear resistance and high mechanical strength. Summary of the Invention

[0004] In order to improve the wear resistance and hydrophobicity of liquid silicone rubber, the present application provides a wear-resistant and hydrophobic liquid silicone rubber and a preparation method thereof.

[0005] The wear-resistant and hydrophobic liquid silicone rubber provided by the present application adopts the following technical scheme:

[0006] A wear-resistant and hydrophobic liquid silicone rubber includes component A and component B. The formula of component A by weight contains the following raw materials: 80-100 parts of base rubber;

[0007] 6-18 parts of vinyl silicone oil;

[0008] 0.5-0.9 part of platinum catalyst;

[0009] The formula of component B by weight contains the following raw materials:

[0010] 70-90 parts of vinyl silicone oil;

[0011] 17-30 parts of hydrogen-containing silicone oil;

[0012] 10-19 parts of perfluorooctylethylene;

[0013] 15-25 parts of trimethoxyhydro-silane;

[0014] 10-25 parts of steel slag;

[0015] 0.15-0.65 part of inhibitor;

[0016] Component A and component B are mixed in a weight ratio of 1:(1-3).

[0017] By adopting the above technical scheme, the vinyl group of the base rubber and the Si-H group of the hydrogen-containing silicone oil undergo a silylation reaction under the action of a platinum catalyst, wherein the inhibitor can reduce the activity of the catalyst, thereby improving its storage stability. In view of the fact that ordinary liquid silicone rubber is not wear-resistant, this application uses steel slag as an additive, and by adjusting the amount of steel slag added, the wear resistance of the liquid silicone rubber is greatly improved. In order to solve the problem of agglomeration and accumulation of steel slag in the liquid silicone rubber matrix, trimethoxyhydrogen silane is first coated on the surface of the steel slag, and then trimethoxyhydrogen silane reacts with perfluorooctylethylene to react with silylation, introducing fluorocarbon chains to the surface of the steel slag, and part of the active hydrogen on the surface of the steel slag reacts with the vinyl group, thereby improving the interfacial compatibility of the steel slag in the liquid silicone rubber matrix, and the fluorocarbon chain increases the hydrophobicity of the liquid silicone rubber.

[0018] Optionally, the particle size of the steel slag is 35-90 μm.

[0019] By adopting the above technical solution, steel slag is used as solid waste and added to liquid silicone rubber so that the waste can be recycled. By adopting the above particle size, the steel slag can be dispersed more evenly in the liquid silicone rubber.

[0020] Optionally, the viscosity of the vinyl silicone oil is in the range of 6000-9000 mPa.s; the mass percentage of vinyl in the vinyl silicone oil is 0.06-0.3%.

[0021] By adopting the above technical scheme, the vinyl content in vinyl silicone oil has a great influence on the mechanical properties of silicone rubber. Vinyl silicone oils of different molecular weights have different viscosities. Low molecular weight vinyl silicone oils have a higher vinyl content, which can effectively increase the crosslinking density of silicone rubber, and further increase its hardness and strength; while reducing the vinyl content reduces the crosslinking points in silicone rubber, reduces the crosslinking density, and reduces the tear strength of silicone rubber.

[0022] Optionally, the vinyl silicone oil is one of vinyl-terminated polydimethylsiloxane or vinyl-terminated polymethylvinylsiloxane.

[0023] By adopting the above technical solution, the vinyl group undergoes an addition reaction with active hydrogen, and the siloxane containing terminal groups and side groups is used as a reaction monomer, which can increase the reaction site. The liquid silicone rubber obtained by the reaction has higher tear strength and wear resistance.

[0024] Optionally, the platinum catalyst is a complex of chloroplatinic acid and divinyltetramethyldisiloxane, the platinum content of the platinum catalyst is 700-9000 ppm, and the inhibitor is an acetylenic alcohol compound.

[0025] By adopting the above technical solutions, the platinum catalyst has high catalytic activity, strong selectivity, is convenient to prepare, has a small usage amount, can inhibit side reactions occurring during the Si-H reaction, and the inhibitor can reduce the activity of the platinum catalyst, thereby improving the storage stability of the liquid silicone rubber.

[0026] Optionally, the hydrogen content of the hydrogen-containing silicone oil is 0.1-0.5 wt%.

[0027] By adopting the above technical solutions, as a cross-linking agent for liquid silicone rubber, the content of Si-H groups in the molecular structure of the hydrogen-containing silicone oil has a significant impact on the vulcanization rate and the properties of the final product of the liquid silicone rubber. As the mass fraction of active hydrogen in the hydrogen-containing silicone oil increases, the more active sites available for cross-linking reaction in the system, the greater the reaction activity and the higher the cross-linking density. Continuing to increase the mass fraction of active hydrogen, due to the proximity of active hydrogen units to each other and mutual shielding, the active hydrogen cannot fully exert its due activity. Therefore, by adopting the above mass ratio, the strength and modulus of the liquid silicone rubber reach the best.

[0028] In a second aspect, the present application provides a method for preparing a wear-resistant and hydrophobic liquid silicone rubber, adopting the following technical solutions:

[0029] A method for preparing a wear-resistant and hydrophobic liquid silicone rubber, comprising the following steps:

[0030] Step 1, stir and mix the base rubber, vinyl silicone oil and platinum catalyst evenly to obtain Component A;

[0031] Step 2, stir and grind the steel slag and trimethoxysilane, then add perfluorooctylethylene, heat and stir to obtain a mixture;

[0032] Step 3, stir and mix the vinyl silicone oil, hydrogen-containing silicone oil, inhibitor and the mixture evenly to obtain Component B, and mix Component A and Component B evenly to obtain the liquid silicone rubber.

[0033] By adopting the above technical solutions, first stir and grind the steel slag and trimethoxysilane to make trimethoxysilane adsorb on the surface of the steel slag. On the one hand, it can improve the dispersion effect of the steel slag in the liquid silicone rubber. On the other hand, mix the steel slag coated with trimethoxysilane and perfluorooctylethylene and heat them to introduce fluorocarbon chains on the surface of the steel slag, which not only improves the interfacial compatibility between the steel slag and the liquid silicone rubber, but also the introduced fluorocarbon chains improve the hydrophobicity of the liquid silicone rubber.

[0034] Optionally, in Step 2, add perfluorooctylethylene, heat to 30-45 °C, stir for 25-35 min to obtain a mixture.

[0035] By adopting the above technical solution, under the action of a platinum catalyst, heating and stirring are carried out to make the vinyl group of perfluorooctylethylene react with the active hydrogen of trimethoxysilane, so that perfluorooctylethylene is introduced onto the surface of steel slag.

[0036] In summary, the present application has the following beneficial effects:

[0037] 1. Since the present application uses steel slag as an additive, by adjusting the addition amount of steel slag, the wear resistance of liquid silicone rubber is greatly improved.

[0038] 2. In the present application, in order to solve the problems of agglomeration and accumulation of steel slag in the liquid silicone rubber matrix, trimethoxysilane is first coated on the surface of steel slag. Immediately afterwards, a hydrosilylation reaction occurs between trimethoxysilane and perfluorooctylethylene, introducing a fluorocarbon chain onto the surface of steel slag. Part of the active hydrogen on the surface of steel slag reacts with the vinyl group, improving the interfacial compatibility of steel slag in the liquid silicone rubber matrix.

[0039] 3. In the method of the present application, by first stirring and grinding steel slag with trimethoxysilane, trimethoxysilane is adsorbed on the surface of steel slag. On the one hand, it can improve the dispersion effect of steel slag in liquid silicone rubber. On the other hand, the steel slag coated with trimethoxysilane is mixed and heated with perfluorooctylethylene, introducing a fluorocarbon chain onto the surface of steel slag, which not only improves the interfacial compatibility between steel slag and liquid silicone rubber, but also the introduced fluorocarbon chain improves the hydrophobicity of liquid silicone rubber. Specific Embodiments

[0040] The present application will be further described in detail below with reference to examples and comparative examples.

[0041] Source of raw materials: The raw materials used in the examples and comparative examples are all commercially available. Among them, the steel slag is purchased from

[0042] Examples

[0043] Example 1

[0044] A preparation method of wear-resistant and hydrophobic liquid silicone rubber includes the following steps:

[0045] Step 1, put the base rubber, vinyl-terminated polymethylvinylsiloxane and platinum catalyst into a vacuum kneader, and at the same time pass in circulating water for cooling, knead for 30 min, and evacuate 3 times to obtain component A. Among them, the viscosity range of vinyl-terminated polymethylvinylsiloxane is 7000 mPa·s; the vinyl mass percentage content is 0.25%, and the platinum content of the platinum catalyst is 5000 ppm; Step 2, mix and stir steel slag and trimethoxysilane for 10 min, grind with a grinder for 10 min, then add perfluorooctylethylene, heat to 40 °C, stir for 30 min, and react to obtain a mixture. Among them, the particle size of the steel slag is 70 μm;

[0046] Step 3: Disperse vinyl-terminated polymethylvinylsiloxane, hydrogen-containing silicone oil, 1-ethynylcyclohexanol and the mixture using a disperser for 3 min, then evacuate to obtain Component B. The hydrogen content of the hydrogen-containing silicone oil is 0.3 wt%. Mix Component A and Component B in a weight ratio of 1:2 and stir for 10 min to obtain liquid silicone rubber.

[0047] Example 2

[0048] A preparation method of wear-resistant and hydrophobic liquid silicone rubber, comprising the following steps:

[0049] Step 1: Put the base rubber, vinyl-terminated polymethylvinylsiloxane and platinum catalyst into a vacuum kneader, while passing in circulating water for cooling, knead for 30 min, and evacuate 3 times to obtain Component A. The viscosity range of the vinyl-terminated polymethylvinylsiloxane is 7000 mPa·s; the vinyl mass percentage content is 0.06%, and the platinum content of the platinum catalyst is 700 ppm. Step 2: Mix steel slag and trimethoxysilane and stir for 10 min, grind with a grinder for 10 min, then add perfluorooctylethylene, heat to 30 °C, and stir for 25 min to obtain a mixture. The particle size of the steel slag is 35 μm.

[0050] Step 3: Disperse vinyl-terminated polymethylvinylsiloxane, hydrogen-containing silicone oil, 1-ethynylcyclohexanol and the mixture using a disperser for 3 min, then evacuate to obtain Component B. The hydrogen content of the hydrogen-containing silicone oil is 0.1 wt%. Mix Component A and Component B in a weight ratio of 1:1 and stir for 10 min to obtain liquid silicone rubber.

[0051] Example 3

[0052] A preparation method of wear-resistant and hydrophobic liquid silicone rubber, comprising the following steps:

[0053] Step 1: Put the base rubber, vinyl-terminated polymethylvinylsiloxane and platinum catalyst into a vacuum kneader, while passing in circulating water for cooling, knead for 30 min, and evacuate 3 times to obtain Component A. The viscosity range of the vinyl-terminated polymethylvinylsiloxane is 9000 mPa·s; the vinyl mass percentage content is 0.3%, and the platinum content of the platinum catalyst is 9000 ppm. Step 2: Mix steel slag and trimethoxysilane and stir for 10 min, grind with a grinder for 10 min, then add perfluorooctylethylene, heat to 45 °C, and stir for 35 min to obtain a mixture. The particle size of the steel slag is 90 μm.

[0054] Step 3: Disperse the mixture of vinyl-terminated polymethylvinylsiloxane, hydrogen-containing silicone oil, and 1-ethynylcyclohexanol using a disperser for 3 min, then evacuate to obtain Component B. The hydrogen content of the hydrogen-containing silicone oil is 0.5 wt%. Mix Component A and Component B in a weight ratio of 1:3 and stir for 10 min to obtain the liquid silicone rubber.

[0055] The components and their corresponding weight parts of the raw materials in Examples 1-3 are shown in Table 1.

[0056] Table 1 Raw materials and their weights (kg) in Examples 1-3

[0057]

[0058] Example 4

[0059] A preparation method of wear-resistant and hydrophobic liquid silicone rubber, which is different from Example 1 in that the particle size of the steel slag is 95 μm.

[0060] Example 5

[0061] A preparation method of wear-resistant and hydrophobic liquid silicone rubber, which is different from Example 1 in that the particle size of the steel slag is 30 μm.

[0062] Example 6

[0063] A preparation method of wear-resistant and hydrophobic liquid silicone rubber, which is different from Example 1 in that perfluorooctylethylene is added in Step 2, heated to 25 °C, and stirred for 20 min to obtain a mixture.

[0064] Example 7

[0065] A preparation method of wear-resistant and hydrophobic liquid silicone rubber, which is different from Example 1 in that perfluorooctylethylene is added in Step 2, heated to 48 °C, and stirred for 40 min to obtain a mixture.

[0066] Comparative Example

[0067] Comparative Example 1

[0068] A preparation method of wear-resistant and hydrophobic liquid silicone rubber, which is different from Example 1 in that the raw material does not include perfluorooctylethylene, and the specific preparation steps of Step 1 are as follows:

[0069] Step 1: Mix the steel slag and trimethoxyhydrosilane and stir for 10 min, then grind using a grinder for 10 min and stir for 30 min to obtain a mixture, where the particle size of the steel slag is 70 μm.

[0070] Comparative Example 2

[0071] A preparation method of wear-resistant hydrophobic liquid silicone rubber, which is different from that of Example 1 in that the raw materials do not include steel slag, and includes the following preparation steps:

[0072] Step 2: Put the base rubber, vinyl-terminated polymethylvinylsiloxane and platinum catalyst into a vacuum kneader, and at the same time pass in circulating water for cooling. Knead for 30 minutes and evacuate 3 times to obtain Component A. The platinum content of the platinum catalyst is 5000 ppm; the viscosity range of the vinyl-terminated polymethylvinylsiloxane is 7000 mPa·s; the mass percentage of vinyl is 0.25%;

[0073] Step 3: Disperse the vinyl-terminated polymethylvinylsiloxane, hydrogen-containing silicone oil, 1-ethynylcyclohexanol, trimethoxyhydroxysilane and perfluorooctylethylene with a disperser for 3 minutes, and evacuate to obtain Component B. The hydrogen content of the hydrogen-containing silicone oil is 0.3 wt%. Mix Component A and Component B in a weight ratio of 1:2 and stir for 10 minutes to obtain liquid silicone rubber.

[0074] Comparative Example 3

[0075] A preparation method of wear-resistant hydrophobic liquid silicone rubber, which is different from that of Example 1 in that the raw materials do not include perfluorooctylethylene and trimethoxyhydroxysilane, and includes the following preparation steps:

[0076] Step 1: Put the base rubber, vinyl-terminated polymethylvinylsiloxane and platinum catalyst into a vacuum kneader, and at the same time pass in circulating water for cooling. Knead for 30 minutes and evacuate 3 times to obtain Component A. The particle size of the steel slag is 70 μm, the platinum content of the platinum catalyst is 5000 ppm; the viscosity range of the vinyl-terminated polymethylvinylsiloxane is 7000 mPa·s; the mass percentage of vinyl is 0.25%;

[0077] Step 2: Disperse the vinyl-terminated polymethylvinylsiloxane, hydrogen-containing silicone oil, 1-ethynylcyclohexanol and steel slag with a disperser for 3 minutes, and evacuate to obtain Component B. The hydrogen content of the hydrogen-containing silicone oil is 0.3 wt%. Mix Component A and Component B in a weight ratio of 1:2 and stir for 10 minutes to obtain liquid silicone rubber.

[0078] Performance detection test

[0079] Detection method

[0080] Use the liquid silicone rubbers prepared in Examples 1-7 and Comparative Examples 1-3 as test specimens.

[0081] Conduct wear tests on the obtained liquid silicone rubber specimens according to GBT 25262-2010 "Guide for Abrasion Testing of Vulcanized Rubber or Thermoplastic Rubber". The testing machine is a Taber abrasion testing machine, and the test results are shown in Table 2.

[0082] The liquid silicone rubbers obtained in Examples 1-7 and Comparative Examples 1-3 were kept at 120 °C for 5 minutes, and then made into standard test pieces (the thickness of the test pieces was required to be 2 mm), and the static contact angle of the test pieces was measured.

[0083] The tear strength was tested according to GB / T528-1999, and the tensile strength was tested according to GB / T528-1998.

[0084] Table 2 Test results of performance detection

[0085]

[0086] Combining Example 1 and Examples 4-5 and combining with Table 2, it can be seen that the finer the particle size of the steel slag, the easier it is to agglomerate, resulting in interface defects, reducing the wear resistance and strength of the liquid silicone rubber matrix. The coarser the particle size of the steel slag, the less uniform the dispersion, reducing the wear resistance and strength of the liquid silicone rubber matrix.

[0087] Combining Example 1 and Examples 6-7 and combining with Table 2, it can be seen that by adjusting the appropriate temperature and stirring time, fluorocarbon chains were successfully introduced onto the surface of the steel slag, and some unreacted active hydrogen groups and vinyl groups present further reacted with the liquid silicone rubber matrix, improving the interfacial compatibility of the steel slag in the liquid silicone rubber matrix.

[0088] Combining Example 1 and Comparative Examples 1-3 and combining with Table 2, it can be seen that by comparing with or without the addition of steel slag, it can be seen that the addition of steel slag improves the abrasion and strength of the liquid silicone rubber. Using steel slag as an additive, by adjusting the addition amount of steel slag, the wear resistance and strength of the liquid silicone rubber are greatly improved. From Comparative Example 1 and Comparative Example 3, it can be seen that perfluorooctylethylene and trimethoxyhydro-silane were introduced. Trimethoxyhydro-silane coated the surface of the steel slag. Immediately afterwards, trimethoxyhydro-silane underwent a hydrosilylation reaction with perfluorooctylethylene, introducing fluorocarbon chains onto the surface of the steel slag. Some of the active hydrogen on the surface of the steel slag underwent a chemical reaction with vinyl groups, further improving the interfacial compatibility of the steel slag in the liquid silicone rubber matrix.

[0089] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the Patent Law.

Claims

1. Preparation method of wear-resistant hydrophobic liquid silicone rubber, characterized in that: It includes component A and component B. The formula of component A by weight contains the following raw materials: 80 - 100 parts of base rubber; 6 - 18 parts of vinyl silicone oil; 0.5 - 0.9 part of platinum catalyst; The formula of component B by weight contains the following raw materials: 70 - 90 parts of vinyl silicone oil; 17 - 30 parts of hydrogen-containing silicone oil; 10 - 19 parts of perfluorooctyl ethylene; 15 - 25 parts of trimethoxyhydroxysilane; 10 - 25 parts of steel slag; 0.15 - 0.65 part of inhibitor; The component A and component B are mixed in a weight ratio of 1:(1 - 3); The particle size of the steel slag is 35 - 90 μm; the viscosity range of the vinyl silicone oil is 6000 - 9000 mPa·s; the vinyl mass percentage content of the vinyl silicone oil is 0.06 - 0.3%; the vinyl silicone oil is one of terminal vinyl polydimethylsiloxane or terminal vinyl polymethylvinylsiloxane; the platinum catalyst is a complex of chloroplatinic acid and divinyltetramethyldisiloxane, and the platinum content of the platinum catalyst is 700 - 9000 ppm, and the inhibitor is an alkynol compound; The preparation includes the following steps: Step 1, stir and mix the base rubber, vinyl silicone oil and platinum catalyst evenly to obtain component A; Step 2, stir and grind the steel slag and trimethoxyhydroxysilane, then add perfluorooctyl ethylene, heat and stir to react to obtain a mixture; Step 3, stir and mix the vinyl silicone oil, hydrogen-containing silicone oil, inhibitor and the mixture evenly to obtain component B, and mix component A and component B evenly to obtain liquid silicone rubber.

2. The preparation method of a wear-resistant hydrophobic liquid silicone rubber according to claim 1, characterized in that: The hydrogen content of the hydrogen-containing silicone oil is 0.1 - 0.5 wt%.

3. The preparation method of a wear-resistant hydrophobic liquid silicone rubber according to claim 1, characterized in that: In step 2, perfluorooctyl ethylene is added, heated to 30 - 45 °C, stirred for 25 - 35 min, and reacted to obtain a mixture.

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