CN110577746B - Low-viscosity high-strength addition type room temperature curing liquid silicone rubber and preparation method thereof - Google Patents
Low-viscosity high-strength addition type room temperature curing liquid silicone rubber and preparation method thereof Download PDFInfo
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- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
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Abstract
The invention discloses low-viscosity high-strength addition type room temperature curing liquid silicone rubber and a preparation method thereof, wherein the low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass: the component A comprises: 45-72 parts of a base polymer, 11-25 parts of a filler, 5-15 parts of a hardness control agent, 2.7-9 parts of a viscosity control agent, 2-6 parts of a cross-linking agent and 1-2 parts of an inhibitor; the component B comprises: 4.5-9 parts of a base polymer, 1.3-4.3 parts of a filler and 1-2 parts of a platinum catalyst; the preparation method comprises the following steps of firstly, independently preparing a component A and a component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 8-10 hours at the temperature of 20-25 ℃ to obtain the silicone rubber elastomer; the liquid silicone rubber has low viscosity and good fluidity, and the silicone rubber elastomer has excellent mechanical property, and can be widely used in the fields of external insulation of power transmission and transformation equipment, moisture-proof and dust-proof sealing of precise circuit boards, encapsulation and repair of special-shaped parts and the like.
Description
Technical Field
The invention belongs to the technical field of silicone rubber, and particularly relates to low-viscosity high-strength liquid silicone rubber capable of being cured and molded at room temperature and a preparation method thereof.
Background
The silicon rubber is (— Si-O-)nThe liquid silicone rubber which is a main chain and has the side group of the high molecular polymer formed by organic groups can be cured at room temperature, and the cured silicone rubber material has good thermal oxidation aging resistance, weather aging resistance, electric arc resistance and excellent electrical insulation performance, so the liquid silicone rubber is widely applied to the fields of external insulation of power equipment, dustproof and waterproof sealing of circuit boards for high-precision electronic and electronic devices, insulation encapsulation of complex special-shaped parts and the like. For example, related patent documents include:
1. CN 108774401A discloses a low-viscosity flame-retardant insulating liquid silicone rubber and a preparation method thereof, wherein a liquid silicone rubber base rubber A consists of linear polysiloxane, a reinforcing filler and a reinforcing filler surface treating agent; the cross-linking agent B consists of hydrogen-containing silicone oil; the component C consists of pigment, fire retardant, catalyst and polymerization inhibitor; the flame retardant is one of titanium dioxide, carbon black and azo compounds or a mixture thereof, in particular to a mixture of titanium dioxide and azo compounds, wherein the azo compounds are azodicarbonamide with the particle size of 20 mu m; the catalyst is a platinum catalyst. Due to the addition of the azo compound, a platinum catalyst can be poisoned and the requirement of room temperature curing is difficult to meet, and the research on the viscosity, the insulativity and the flame retardance of the liquid silicone rubber is emphasized, and the relation between the viscosity and the mechanical property of the liquid silicone rubber is not involved.
2. CN 102924928A discloses a preparation method of low-viscosity liquid silicone rubber, which adopts vinyl polysiloxane as a liquid silicone rubber matrix and white carbon black as an inorganic filler, and after mixing, adds an inhibitor, a platinum complex and hydrogen-containing silicone oil, fully stirs and defoams in vacuum to obtain transparent liquid silicone rubber. Although the viscosity of the liquid silicone rubber can be controlled to be 2000-6000 mPa.S after being cured, no description is provided for proving that the liquid silicone rubber has a mechanical property index of high mechanical strength and low strength, so that the low-viscosity transparent liquid silicone rubber is only suitable for packaging materials in the field of electronic industry, and the problems of fluidity, film forming property and processability of the liquid silicone rubber are mainly solved by reducing the viscosity of rubber materials.
3. CN 109266012A discloses a low-viscosity high-strength addition type liquid silicone rubber, which comprises the following raw materials in parts by weight: 60-140 parts of vinyl polysiloxane, 4-24 parts of white carbon black, 1-4 parts of inhibitor, 0.1-0.24 part of catalyst, 15-25 parts of hydrogen-containing silicone oil, 40-160 parts of bismaleimide resin, 15-35 parts of GRT fiber, 0.5-2.5 parts of tetramethyl thiuram disulfide and 2.5-4.5 parts of nano argil, and the raw materials are stirred and mixed at high speed at the temperature of 1000-1200 ℃ to obtain the low-viscosity high-strength addition type liquid silicone rubber. However, at the temperature of 1000-1200 ℃, raw materials such as polysiloxane, catalyst and hydrogen-containing silicone oil are decomposed into substances such as silicon dioxide at high temperature, and the silicone rubber cannot be prepared.
With the development of advanced equipment towards high performance, precision and integration, higher requirements are put forward on the curing speed, viscosity and mechanical property of liquid silicone rubber, for example, when manufacturing a high-pressure prefabricated cable accessory of 110kv or above, the liquid silicone rubber is required to have not only lower viscosity for injection molding, but also good mechanical property to ensure that the cable accessory is not damaged in the actual use process; when the touchable lightning arrester is manufactured, the liquid silicon rubber is required to have lower viscosity to be beneficial to pouring and encapsulating, and meanwhile, bubbles between the liquid silicon rubber and a zinc oxide valve plate interface can be conveniently and rapidly escaped. According to the mechanism of the white carbon black reinforced polymer, in order to obtain good mechanical properties, a certain amount of white carbon black needs to be added into the liquid silicone rubber, but the viscosity of the liquid silicone rubber is obviously increased; if the addition amount of the white carbon black is not enough, the viscosity of the liquid silicone rubber is low, but the mechanical property is poor, so that the problem that the liquid silicone rubber has both low viscosity and good mechanical property is not easy to solve.
Disclosure of Invention
In order to solve the problems, the invention provides low-viscosity high-strength addition type room temperature curing liquid silicone rubber, a centralized cross-linked network structure formed by polysiloxane with different composition structures under the catalysis of platinum is selected, so that the tearing strength and the elongation at break of the rubber can be improved, and the viscosity of the rubber can be effectively controlled; the addition of white carbon black improves the tensile strength and the electrical strength of the sizing material, and the viscosity of the sizing material can be properly reduced by matching with a viscosity control agent. The silicon rubber elastomer obtained after curing can be widely used in the fields of external insulation of power transmission and transformation equipment, moisture-proof and dust-proof sealing of precise circuit boards, encapsulation and repair of special-shaped parts and the like.
The invention is realized by the following technical scheme: the low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 45-72 parts of a base polymer, 11-25 parts of a filler, 5-15 parts of a hardness control agent, 2.7-9 parts of a viscosity control agent, 2-6 parts of a cross-linking agent and 1-2 parts of an inhibitor;
the component B comprises: 4.5-9 parts of a basic polymer, 1.3-4.3 parts of a filler and 1-2 parts of a platinum catalyst.
In the invention, the basic polymer is linear polysiloxane with the vinyl content of 0.2-0.5% by mass, and the structure of the linear polysiloxane is shown as the following formula (I):
(ViMe2SiO1/2)2(ViMeSiO)m(Me2SiO)n （Ⅰ）
wherein m and n are both natural numbers > 1;
in the present invention, the filler is selected from fillers having a specific surface area of 100m2/g、150m2/g、200m2/g、250m2/g、300m2The precipitated silica or fumed silica is one or a mixture of more of the precipitated silica and the fumed silica.
In the invention, the hardness control agent is branched polysiloxane with the vinyl content of 2-5% by mass, and the structure of the branched polysiloxane is shown as the following formula (II):
[(Me)3SiO1/2]a[Vi(Me)SiO2/2]b[SiO4/2]c （Ⅱ）
wherein a, b and c are all natural numbers > 1;
the viscosity control agent is linear polysiloxane containing methyl, alkoxy or epoxy end capping, the viscosity of the linear polysiloxane is 5-100 mpa.s, and the structure of the linear polysiloxane is shown as the following formula (III):
(RMe2SiO1/2)2(Me2SiO)m （Ⅲ）
wherein R represents a methyl group, an alkoxy group or an epoxy group; m is a natural number greater than 1;
in the invention, the cross-linking agent is linear polysiloxane with hydrogen content of 0.5-1.0% by mass, and the structure of the cross-linking agent is shown as the following formula (IV):
(HMe2SiO1/2)2(HMeSiO)m(Me2SiO)n （Ⅳ）
wherein m and n are both natural numbers > 1;
in the invention, the inhibitor is one or a mixture of two of polydivinyltetramethyldisiloxane, tetravinyltetramethylcyclotetrasiloxane and tetramethyldivinyldisiloxane.
In the invention, the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The preparation method of the low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises the following steps: the preparation method comprises the following steps of firstly, independently preparing a component A and a component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 8-10 hours at the temperature of 20-25 ℃ to obtain the silicone rubber elastomer; the viscosity of the liquid silicone rubber obtained after the component A and the component B are mixed is 9300-21000 mpa.s; the cured silicone rubber elastomer has a Shore A hardness of 36-42, a tensile strength of 5-7.4 Mpa, an elongation at break of 400-510%, and a tear strength of 18-33 kN.m-1Electrical strength of 22-29 kV/mm-1Volume resistivity of 1015Ω·cm。
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the mechanical property of the liquid silicone rubber not only fully considers the filling amount of the filler, but also effectively improves the tearing strength and the elongation at break of the rubber material by selecting a concentrated crosslinking network structure formed by polysiloxane with different composition structures. Namely, the hardness control agent uses branched polysiloxane with 2-5% of vinyl mass percent, the cross-linking agent uses linear polysiloxane with 0.5-1.0% of hydrogen mass percent, and the two polysiloxanes with different composition structures are matched to form a centralized cross-linking network structure, so that the tearing strength and the elongation at break of the liquid silicone rubber are greatly improved.
(2) On the premise of ensuring certain mechanical properties of the silicone rubber, the linear polysiloxane with the viscosity of 5-100 mpa.s is added as a viscosity control agent, so that the silicone rubber has a good effect of properly reducing the viscosity of the liquid silicone rubber.
(3) The mixing of the component A and the component B can be completed only by conventional mixing equipment. Does not contain toxic and harmful substances, does not need special equipment in the production process, does not use toxic solvents, and is easy for large-scale production.
(4) The liquid silicon rubber does not contain substances which can poison a platinum catalyst, such as nitrogen, phosphorus, sulfur, organic tin, heavy metal and the like, the viscosity of the uniformly mixed component A and the component B is 9300-21000 mpa.s according to the mass part ratio of 9:1, and the specific lower viscosity and better fluidity of the liquid silicon rubber are ensured; meanwhile, the rubber material obtained by mixing the component A and the component B can be cured for 8-10 hours at the temperature of 20-25 ℃ to obtain the silicone rubber elastomer with good mechanical property, wherein the Shore A hardness is 36-42, the tensile strength is 5-7.4 Mpa, the elongation at break is 400-510%, and the tear strength is 18-33 kN.m-1And an electrical strength of 22 to 29 kV/mm-1Volume resistivity of 1015Omega cm. The curing and forming process does not need an additional heating and warming device and a pressure pumping device, the construction process is simple and quick, the production efficiency of the sizing material is improved, and the outdoor operation and use are convenient.
Detailed Description
The present invention will be further described in detail with reference to the following examples for better explanation of the present invention, but the embodiments of the present invention are not limited thereto.
Example 1
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 45 parts of base polymer, 11 parts of filler, 8 parts of hardness control agent, 4 parts of viscosity control agent, 3 parts of crosslinking agent and 1 part of inhibitor;
the component B comprises: 5 parts of base polymer, 2 parts of filler and 1 part of platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.3%;
the filler has a specific surface area of 200m2Fumed silica per gram;
the hardness control agent is branched polysiloxane with 3 percent of vinyl content (mass percentage);
the viscosity control agent is a linear polysiloxane with 5mpa.s methyl end capping viscosity;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 0.8 percent;
the inhibitor is tetramethyl divinyl disiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 10 hours at 20 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 2
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 72 parts of base polymer, 23 parts of filler, 15 parts of hardness control agent, 7.15 parts of viscosity control agent, 5 parts of crosslinking agent and 1.2 parts of inhibitor;
the component B comprises: 8 parts of base polymer, 4.3 parts of filler and 1.4 parts of platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.5%;
the filler has a specific surface area of 150m2Precipitated silica in a/g ratio;
the hardness control agent is branched polysiloxane with 2 percent of vinyl content (mass percentage);
the viscosity control agent is a linear polysiloxane with 5mpa.s methyl end capping viscosity;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 0.6 percent;
the inhibitor is tetravinyl tetramethyl cyclotetrasiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 8 hours at 25 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 3
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 45 parts of base polymer, 11 parts of filler, 8 parts of hardness control agent, 2.7 parts of viscosity control agent, 2 parts of crosslinking agent and 1.5 parts of inhibitor;
the component B comprises: 5 parts of base polymer, 1.3 parts of filler and 1.5 parts of platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.4%;
the filler has a specific surface area of 100m2Fumed silica per gram;
the hardness control agent is branched polysiloxane with 5 percent of vinyl content (mass percentage);
the viscosity control agent is a linear polysiloxane with 20mpa.s viscosity and alkoxy end capping;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 1.0 percent;
the inhibitor is polydivinyltetramethyldisiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The preparation method comprises the following steps of preparing the component A and the component B independently, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 9 hours at 23 ℃ to obtain the silicone rubber elastomer. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 4
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 72 parts of base polymer, 23 parts of filler, 15 parts of hardness control agent, 6 parts of viscosity control agent, 5 parts of crosslinking agent and 1.4 parts of inhibitor;
the component B comprises: 9 parts of base polymer, 3 parts of filler and 1.6 parts of platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.38%;
the filler has a specific surface area of 200m220 parts of fumed silica/g and 150m of specific surface area26 parts of gas phase white carbon black;
the hardness control agent is branched polysiloxane with 5 percent of vinyl content (mass percentage);
the viscosity control agent is a linear polysiloxane with a viscosity of 50mpa.s and alkoxy end capping;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 0.6 percent;
the inhibitor is a mixture of 0.8 part of tetravinyl tetramethylcyclotetrasiloxane and 0.6 part of tetramethyl divinyl disiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 9.5 hours at 22 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 5
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 45 parts of base polymer, 15 parts of filler, 8.4 parts of hardness control agent, 5 parts of viscosity control agent, 2 parts of crosslinking agent and 1.1 parts of inhibitor;
the component B comprises: 5.5 parts of a base polymer, 2 parts of a filler and 1 part of a platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.42%;
the filler has a specific surface area of 250m210 parts of fumed silica/g and 150m of specific surface area27 parts of gas phase white carbon black;
the hardness control agent is branched polysiloxane with 2 percent of vinyl content (mass percentage);
the viscosity control agent is epoxy-terminated linear polysiloxane with the viscosity of 45 mpa.s;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 1.0 percent;
the inhibitor is a mixture of 0.6 part of tetramethyl divinyl disiloxane and 0.5 part of polydivinyl tetramethyl disiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 9.5 hours at 21 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 6
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 72 parts of base polymer, 23 parts of filler, 8 parts of hardness control agent, 9 parts of viscosity control agent, 6 parts of crosslinking agent and 1.7 parts of inhibitor;
the component B comprises: 8 parts of base polymer, 3.8 parts of filler and 1.5 parts of platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.2%;
the filler has a specific surface area of 200m2Precipitated silica 15 parts/g and specific surface area 100m211.8 parts of a mixture of/g precipitated silica;
the hardness control agent is branched polysiloxane with 5 percent of vinyl content (mass percentage);
the viscosity control agent is epoxy-terminated linear polysiloxane with viscosity of 22 mpa.s;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 0.5 percent;
the inhibitor is tetramethyl divinyl disiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 8.5 hours at 24 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 7
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 45 parts of base polymer, 15 parts of filler, 5 parts of hardness control agent, 3 parts of viscosity control agent, 2 parts of crosslinking agent and 2 parts of inhibitor;
the component B comprises: 4.5 parts of a base polymer, 1.5 parts of a filler and 2 parts of a platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.5%;
the filler has a specific surface area of 300m2Fumed silica per gram;
the hardness control agent is branched polysiloxane with 5 percent of vinyl content (mass percentage);
the viscosity control agent is a methyl terminated linear polysiloxane with the viscosity of 100 mpa.s;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 1.0 percent;
the inhibitor is tetramethyl divinyl disiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 9 hours at 20 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 8
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 69 parts of base polymer, 25 parts of filler, 12 parts of hardness control agent, 5 parts of viscosity control agent, 3.2 parts of crosslinking agent and 1 part of inhibitor;
the component B comprises: 8 parts of base polymer, 2.8 parts of filler and 2 parts of platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.25%;
the filler has a specific surface area of 250m2Fumed silica per gram;
the hardness control agent is branched polysiloxane with 2 percent of vinyl content (mass percentage);
the viscosity control agent is a viscosity 68mpa.s alkoxy-terminated linear polysiloxane;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 0.8 percent;
the inhibitor is a mixture of 0.5 part of polydivinyltetramethyldisiloxane and 0.5 part of tetravinyltetramethylcyclotetrasiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 9 hours at 25 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Example 9
The low-viscosity high-strength addition type room temperature curing liquid silicone rubber comprises a component A and a component B in parts by mass as follows:
the component A comprises: 67 parts of base polymer, 20 parts of filler, 6 parts of hardness control agent, 5 parts of viscosity control agent, 3 parts of crosslinking agent and 1.6 parts of inhibitor;
the component B comprises: 7.3 parts of a base polymer, 3 parts of a filler and 1.1 parts of a platinum catalyst;
wherein the content of the first and second substances,
the base polymer was a linear polysiloxane having a vinyl content (mass%) of 0.35%;
the filler has a specific surface area of 150m210 parts of fumed silica/g and 200m of specific surface area2Precipitated silica 8 parts/g and specific surface area 300m25 parts of precipitated silica/g of the mixture;
the hardness control agent is branched polysiloxane with vinyl content (mass percentage) of 3.3%;
the viscosity control agent is a linear polysiloxane with a viscosity of 35mpa.s methyl end capping;
the cross-linking agent is linear polysiloxane with hydrogen content (mass percentage) of 0.6 percent;
the inhibitor is tetramethyl divinyl disiloxane;
the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
The silicone rubber elastomer is prepared by separately preparing the component A and the component B, mixing the component A and the component B according to the mass part ratio of 9:1, and curing for 8 hours at 25 ℃. The elastomers were subjected to relevant performance tests (liquid silicone rubber viscosity, mechanical properties, electrical properties, hardness, etc.), and the results are shown in table 1.
Table 1 liquid silicone rubber property test data
Comparative example 1
In this comparative example, the vinyl content of the hardness-controlling agent in the component A was adjusted on the basis of example 1, and in this comparative example, a branched polysiloxane having a vinyl content (mass percentage) of 1.2% was added as the hardness-controlling agent, and the remaining formulation components and preparation method were the same as in example 1. The comparative example was subjected to a performance test with the silicone rubber elastomer obtained in example 1, and the results are shown in table 2.
TABLE 2
Comparative example 2
This comparative example was conducted in the same manner as in example 9 except that the functional group contained in the viscosity control agent in the component A was adjusted and 5 parts of a hydroxyl-terminated linear polysiloxane having a viscosity of 35mpa.s was added as the viscosity control agent in example 9. The comparative example was subjected to a performance test with the silicone rubber elastomer obtained in example 9, and the results are shown in Table 3.
TABLE 3
Comparative example 3
In this comparative example, the amount of the platinum catalyst in the component B was adjusted based on example 5, and in this comparative example, 0.8 part of the platinum catalyst was added, and the remaining formulation components and preparation method were the same as in example 5. The comparative example was subjected to a performance test with the silicone rubber elastomer obtained in example 5, and the results are shown in Table 4.
TABLE 4
Comparative example 4
In the comparative example, on the basis of example 3, the specific surface areas of the white carbon black filler in the component A and the component B are adjusted, and in the comparative example, 11 parts of the component A is added, and the specific surface area is 400m2The gas phase white carbon black of per gram, the component B is added with 1.3 parts of specific surface area 400m2(g) fumed silica, and the rest formulaParts and preparation were the same as in example 3. The comparative example was subjected to a performance test with the silicone rubber elastomer obtained in example 3, and the results are shown in Table 5.
TABLE 5
As can be seen from the performance test data in tables 2 to 5, the vinyl content of the hardness control agent, the functional group contained in the viscosity control agent, the dosage of the platinum catalyst, the specific surface area of the white carbon black and other factors can all have significant influence on the viscosity, the mechanical property and the electrical property of the liquid silicone rubber. In the invention, a hardness control agent and a viscosity control agent are innovatively used, so that the specific low viscosity and good fluidity of the liquid silicone rubber are ensured, more ideal mechanical properties can be obtained, and the liquid silicone rubber can be cured and molded at room temperature.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (6)
1. A low-viscosity high-strength addition type room temperature curing liquid silicone rubber is characterized in that: the paint consists of a component A and a component B in parts by mass as follows:
the component A comprises: 45-72 parts of a base polymer, 11-25 parts of a filler, 5-15 parts of a hardness control agent, 2.7-9 parts of a viscosity control agent, 2-6 parts of a cross-linking agent and 1-2 parts of an inhibitor;
the component B comprises: 4.5-9 parts of a base polymer, 1.3-4.3 parts of a filler and 1-2 parts of a platinum catalyst;
the hardness control agent is branched polysiloxane with the vinyl content of 2-5% in percentage by mass, and the structure of the branched polysiloxane is shown as the following formula (II):
[(Me)3SiO1/2]a[Vi(Me)SiO2/2]b[SiO4/2]c （Ⅱ）
wherein a, b and c are all natural numbers > 1;
the viscosity control agent is linear polysiloxane containing methyl, alkoxy or epoxy end capping, the viscosity of the linear polysiloxane is 5-100 mpa.s, and the structure of the linear polysiloxane is shown as the following formula (III):
(RMe2SiO1/2)2(Me2SiO)m （Ⅲ）
wherein R represents a methyl group, an alkoxy group or an epoxy group; m is a natural number greater than 1;
the cross-linking agent is linear polysiloxane with hydrogen content of 0.5-1.0% by mass, and the structure of the cross-linking agent is shown as the following formula (IV):
(HMe2SiO1/2)2(HMeSiO)m(Me2SiO)n （Ⅳ）
wherein m and n are both natural numbers > 1;
the viscosity of the liquid silicone rubber obtained after the component A and the component B are mixed is 9300-21000 mpa.s; the cured silicone rubber elastomer has a Shore A hardness of 36-42, a tensile strength of 5-7.4 Mpa, an elongation at break of 400-510%, and a tear strength of 18-33 kN.m-1Electrical strength of 22-29 kV/mm-1Volume resistivity of 1015Ω·cm。
2. The low viscosity high strength addition type room temperature curing liquid silicone rubber according to claim 1, wherein: the base polymer is linear polysiloxane with the vinyl content of 0.2-0.5% by mass, and the structure of the base polymer is shown as the following formula (I):
(ViMe2SiO1/2)2(ViMeSiO)m(Me2SiO)n （Ⅰ）
wherein m and n are both natural numbers > 1.
3. The low viscosity high strength addition type room temperature curing liquid silicone rubber according to claim 1, wherein: the filler is selected from the group consisting of 100m specific surface area2/g、150m2/g、200m2/g、250m2/g、300m2The precipitated silica or fumed silica is one or a mixture of more of the precipitated silica and the fumed silica.
4. The low viscosity high strength addition type room temperature curing liquid silicone rubber according to claim 1, wherein: the inhibitor is one or a mixture of two of polydivinyltetramethyldisiloxane, tetravinyltetramethylcyclotetrasiloxane and tetramethyldivinyldisiloxane.
5. The low viscosity high strength addition type room temperature curing liquid silicone rubber according to claim 1, wherein: the platinum catalyst is a complex of chloroplatinic acid and vinyl siloxane.
6. A method for preparing the low viscosity high strength addition type room temperature curing liquid silicone rubber according to any one of claims 1 to 5, wherein: the silicone rubber elastomer is prepared by separately preparing a component A and a component B, mixing the component A and the component B according to the mass ratio of 9:1, and curing for 8-10 hours at the temperature of 20-25 ℃.
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| CN102337032A (en) * | 2010-06-11 | 2012-02-01 | 信越化学工业株式会社 | Curable silicone gel composition |
| CN102414275A (en) * | 2009-05-29 | 2012-04-11 | 道康宁公司 | Silicone composition for producing transparent silicone materials and optical devices |
| WO2018125506A1 (en) * | 2016-12-30 | 2018-07-05 | Ethicon, Inc. | Silicone compositions rapidly cross-linkable at ambient temperatures and methods of making and using same |
| CN109266012A (en) * | 2018-09-04 | 2019-01-25 | 东莞新东方科技有限公司 | A kind of low viscosity high intensity add-on type liquid silicon rubber |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102414275A (en) * | 2009-05-29 | 2012-04-11 | 道康宁公司 | Silicone composition for producing transparent silicone materials and optical devices |
| CN102337032A (en) * | 2010-06-11 | 2012-02-01 | 信越化学工业株式会社 | Curable silicone gel composition |
| WO2018125506A1 (en) * | 2016-12-30 | 2018-07-05 | Ethicon, Inc. | Silicone compositions rapidly cross-linkable at ambient temperatures and methods of making and using same |
| CN109266012A (en) * | 2018-09-04 | 2019-01-25 | 东莞新东方科技有限公司 | A kind of low viscosity high intensity add-on type liquid silicon rubber |
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