Vulcanized silicone rubber for automobile ornaments and preparation method of vulcanized silicone rubber

Abstract

The invention relates to vulcanized silicone rubber for automobile ornaments and a preparation method thereof, and belongs to the technical field of high polymer materials. The vulcanized silicone rubber for the automobile ornament is prepared from the following raw materials in parts by weight: 100 to 120 parts of raw rubber, 20 to 30 parts of modified white carbon black, 2 to 3 parts of filler, 0.5 to 1 part of coupling agent, 5 to 8 parts of cross-linking agent and 0.3 to 0.5 part of catalyst. By modifying the white carbon black, silicon hydroxyl on the surface of the white carbon black is reduced, so that the side chain aging reaction of the silicone rubber is effectively reduced, and in addition, the filler consisting of nano silicon dioxide and nano titanium dioxide is added, so that the main chain stability of the silicone rubber is improved, and the high-temperature resistance of the silicone rubber is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and relates to vulcanized silicone rubber for automobile accessories and a preparation method thereof. Background Art

[0002] When single-component room temperature vulcanized (RTV) silicone rubber is used, it is squeezed out of a sealed container, and the glue liquid crosslinks and solidifies after contacting moisture or water in the air. 2.1 The automotive industry RTV sealant uses an elastomer. It uses terminal hydroxyl polydimethylsiloxane as a binder, supplemented by fillers, crosslinkers, catalysts, tackifiers, etc. RTV sealants are mostly used in automotive flat sealing parts, such as oil pans, gearboxes, axle joints, engine covers, and large passenger car window glass caulking and sealing. When silicone rubber is used under high temperature conditions, the main chain or side chain of silicone rubber will undergo aging reaction, which reduces the main performance of silicone rubber. When the temperature is below 180℃, the side groups of the main chain of silicone rubber are usually oxidized, that is, the side chain oxidation is dominant, which will not reduce the mechanical strength of silicone rubber, but the hardness will increase slightly, causing the material to lose some elasticity. When the temperature rises further, the main chain degradation causes the silicone rubber molecular chain to break, forming smaller network structure units or lower chain units. At this time, the silicone rubber will become soft and sticky until it completely loses its performance. Summary of the invention

[0003] The present invention relates to a vulcanized silicone rubber for automobile accessories and a preparation method thereof, and belongs to the technical field of polymer materials. The vulcanized silicone rubber for automobile accessories disclosed in the present invention comprises the following raw materials in parts by weight: 100-120 parts of raw rubber, 20-30 parts of modified white carbon black, 2-3 parts of filler, 0.5-1 part of coupling agent, 5-8 parts of crosslinking agent and 0.3-0.5 parts of catalyst. By modifying white carbon black, the silanol group on its surface is reduced, thereby effectively reducing the aging reaction of the silicone rubber side chain. In addition, fillers composed of nano silicon dioxide and nano titanium dioxide are added to improve the main chain stability of the silicone rubber, and further improve its high temperature resistance.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A vulcanized silicone rubber for automobile accessories comprises the following raw materials in parts by weight: 100-120 parts of raw rubber, 20-30 parts of modified white carbon black, 2-3 parts of filler, 0.5-1 part of coupling agent, 5-8 parts of crosslinking agent and 0.3-0.5 parts of catalyst.

[0005] Furthermore, the preparation method of the modified silica comprises the following steps: (1) stirring white carbon black and water to form a suspension, then heating the suspension, adding a coupling agent and a surfactant to obtain a mixture; (2) The pH of the mixture is adjusted, and then the supernatant is removed by centrifugation, and the solid is dried to obtain modified silica.

[0006] Furthermore, in the step (1), the mass ratio of white carbon black, water, coupling agent and surfactant is 5-10:90-100:0.25-0.35:0.4-0.5, wherein the coupling agent is KH550 and the surfactant is sodium dodecyl sulfate.

[0007] Furthermore, in the step (1), the heating temperature is 74-78° C., and the mixing time is 2-3 h.

[0008] Furthermore, in the step (2), the pH is 9-10, the rotation speed of the centrifugal separation is 500-800 r / min, and the temperature and time of the drying are 80-100° C. and 1-2 h, respectively.

[0009] A method for preparing vulcanized silicone rubber for automobile accessories, the method for preparing vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

[0010] Furthermore, the heating temperature and time are 180-190° C. and 1-2 h, and the filler is composed of nano-silicon dioxide and nano-titanium dioxide in a mass ratio of 1:1.

[0011] Furthermore, the coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08~0.09MPa.

[0012] Beneficial effects of the present invention: The invention reduces the silanol groups on the surface of white carbon black by modifying the white carbon black, thereby effectively reducing the aging reaction of the side chain of silicone rubber. In addition, fillers composed of nano silicon dioxide and nano titanium dioxide are added to improve the main chain stability of the silicone rubber and further improve its high temperature resistance. DETAILED DESCRIPTION

[0013] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with embodiments.

[0014] The raw rubber involved in the present invention is terminal hydroxyl polydimethylsiloxane, with a viscosity of (25°C, 5000 mPa·s, and a polymerization degree of 1550), a particle size of nano silicon dioxide of 5 nm, and a particle size of nano titanium dioxide of 4 nm.

[0015] Example 1 A vulcanized silicone rubber for automobile accessories comprises the following raw materials in parts by weight: 100 parts of raw rubber, 20 parts of modified white carbon black, 2 parts of filler, 0.5 parts of coupling agent, 5 parts of cross-linking agent and 0.3 parts of catalyst.

[0016] The preparation method of the modified white carbon black comprises the following steps: (1) stirring white carbon black and water to form a suspension, then heating the suspension, adding a coupling agent and a surfactant to obtain a mixture; (2) The pH of the mixture is adjusted, and then the supernatant is removed by centrifugation, and the solid is dried to obtain modified silica.

[0017] In the step (1), the mass ratio of white carbon black, water, coupling agent and surfactant is 5:90:0.25:0.4, wherein the coupling agent is KH550 and the surfactant is sodium dodecyl sulfate.

[0018] The heating temperature in step (1) is 74° C., and the mixing time is 2 h.

[0019] In the step (2), the pH is 9, the rotation speed of the centrifugal separation is 500 r / min, and the temperature and time of the drying are 80° C. and 1 h, respectively.

[0020] A method for preparing vulcanized silicone rubber for automobile accessories, the method for preparing vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

[0021] The heating temperature and time are 180° C. and 1 hour respectively, and the filler is composed of nano silicon dioxide and nano titanium dioxide in a mass ratio of 1:1.

[0022] The coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08 MPa.

[0023] Example 2 A vulcanized silicone rubber for automobile accessories comprises the following raw materials in parts by weight: 110 parts of raw rubber, 25 parts of modified white carbon black, 2.5 parts of filler, 0.8 parts of coupling agent, 6 parts of cross-linking agent and 0.4 parts of catalyst.

[0024] The preparation method of the modified white carbon black comprises the following steps: (1) stirring white carbon black and water to form a suspension, then heating the suspension, adding a coupling agent and a surfactant to obtain a mixture; (2) The pH of the mixture is adjusted, and then the supernatant is removed by centrifugation, and the solid is dried to obtain modified silica.

[0025] In the step (1), the mass ratio of white carbon black, water, coupling agent and surfactant is 7:95:0.3:0.45, wherein the coupling agent is KH550 and the surfactant is sodium dodecyl sulfate.

[0026] The heating temperature in step (1) is 76° C., and the mixing time is 2.5 h.

[0027] In the step (2), the pH is 9, the rotation speed of the centrifugal separation is 650 r / min, and the temperature and time of the drying are 90° C. and 1.5 h, respectively.

[0028] A method for preparing vulcanized silicone rubber for automobile accessories, the method for preparing vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

[0029] The heating temperature and time are 185° C. and 1.5 h respectively, and the filler is composed of nano silicon dioxide and nano titanium dioxide in a mass ratio of 1.5:1.

[0030] The coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08 MPa.

[0031] Example 3 A vulcanized silicone rubber for automobile accessories comprises the following raw materials in parts by weight: 120 parts of raw rubber, 30 parts of modified white carbon black, 3 parts of filler, 1 part of coupling agent, 8 parts of cross-linking agent and 0.5 parts of catalyst.

[0032] The preparation method of the modified white carbon black comprises the following steps: (1) stirring white carbon black and water to form a suspension, then heating the suspension, adding a coupling agent and a surfactant to obtain a mixture; (2) The pH of the mixture is adjusted, and then the supernatant is removed by centrifugation, and the solid is dried to obtain modified silica.

[0033] In the step (1), the mass ratio of white carbon black, water, coupling agent and surfactant is 10:100:0.35:0.5, wherein the coupling agent is KH550 and the surfactant is sodium dodecyl sulfate.

[0034] The heating temperature in step (1) is 78° C. and the mixing time is 3 hours.

[0035] In the step (2), the pH is 10, the rotation speed of the centrifugal separation is 800 r / min, and the temperature and time of the drying are 100° C. and 2 h, respectively.

[0036] A method for preparing vulcanized silicone rubber for automobile accessories, the method for preparing vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

[0037] The heating temperature and time are 190° C. and 2 hours respectively, and the filler is composed of nano silicon dioxide and nano titanium dioxide in a mass ratio of 2:1.

[0038] The coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08~0.09MPa.

[0039] Comparative Example 1 On the basis of Example 2, a vulcanized silicone rubber for automobile accessories is provided, which comprises the following raw materials in parts by weight: 110 parts of raw rubber, 25 parts of modified silica, 2.5 parts of filler, 0.8 parts of coupling agent, 6 parts of cross-linking agent and 0.4 parts of catalyst.

[0040] The preparation method of the modified white carbon black comprises the following steps: (1) stirring white carbon black and water to form a suspension, then heating the suspension, adding a coupling agent and a surfactant to obtain a mixture; (2) The pH of the mixture is adjusted, and then the supernatant is removed by centrifugation, and the solid is dried to obtain modified silica.

[0041] In the step (1), the mass ratio of white carbon black, water, coupling agent and surfactant is 7:95:0.3:0.45, wherein the coupling agent is KH550 and the surfactant is sodium dodecyl sulfate.

[0042] The heating temperature in step (1) is 76° C., and the mixing time is 2.5 h.

[0043] In the step (2), the pH is 9, the rotation speed of the centrifugal separation is 650 r / min, and the temperature and time of the drying are 90° C. and 1.5 h, respectively.

[0044] A method for preparing vulcanized silicone rubber for automobile accessories, the method for preparing vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

[0045] The heating temperature and time are 185° C. and 1.5 h respectively, and the filler is nano-silicon dioxide.

[0046] The coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08 MPa.

[0047] Comparative Example 2 On the basis of Example 2, a vulcanized silicone rubber for automobile accessories is provided, which comprises the following raw materials in parts by weight: 110 parts of raw rubber, 25 parts of modified silica, 2.5 parts of filler, 0.8 parts of coupling agent, 6 parts of cross-linking agent and 0.4 parts of catalyst.

[0048] The preparation method of the modified white carbon black comprises the following steps: (1) stirring white carbon black and water to form a suspension, then heating the suspension, adding a coupling agent and a surfactant to obtain a mixture; (2) The pH of the mixture is adjusted, and then the supernatant is removed by centrifugation, and the solid is dried to obtain modified silica.

[0049] In the step (1), the mass ratio of white carbon black, water, coupling agent and surfactant is 7:95:0.3:0.45, wherein the coupling agent is KH550 and the surfactant is sodium dodecyl sulfate.

[0050] The heating temperature in step (1) is 76° C., and the mixing time is 2.5 h.

[0051] In the step (2), the pH is 9, the rotation speed of the centrifugal separation is 650 r / min, and the temperature and time of the drying are 90° C. and 1.5 h, respectively.

[0052] A method for preparing vulcanized silicone rubber for automobile accessories, the method for preparing vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

[0053] The heating temperature and time are 185° C. and 1.5 h respectively, and the filler is nano titanium dioxide.

[0054] The coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08 MPa.

[0055] Comparative Example 3 On the basis of Example 2, a vulcanized silicone rubber for automobile accessories is provided, which includes the following raw materials in parts by weight: 110 parts of raw rubber, 25 parts of white carbon black, 2.5 parts of filler, 0.8 parts of coupling agent, 6 parts of cross-linking agent and 0.4 parts of catalyst.

[0056] A method for preparing vulcanized silicone rubber for automobile accessories, the method for preparing vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

[0057] The heating temperature and time are 185° C. and 1.5 h respectively, and the filler is composed of nano silicon dioxide and nano titanium dioxide in a mass ratio of 1.5:1.

[0058] The coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08 MPa.

[0059] Performance Testing The vulcanized silicone rubber prepared in Examples 1-3 and Comparative Examples 1-3 were used as samples to test the tensile strength and elongation at break according to GB / T528-2009, the hardness according to GB / 531-2008, and the hot air accelerated aging according to GB / T3512-2001. The test results are shown in Table 1.

[0060] Table 1 Test results Sample Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 hardness 35 36 34 30 31 35 Tensile strength / MPa 2.88 2.94 2.86 2.73 2.76 2.89 Elongation at break % 267 266 270 238 240 265 After aging at 160℃ for 24h Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 hardness 35 36 35 31 32 39 Tensile strength / MPa 2.89 2.94 2.87 2.70 2.75 2.94 Elongation at break % 266 267 270 236 237 178 After aging at 300℃ for 2h Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 hardness 34 35 34 18 19 20 Tensile strength / MPa 2.86 2.90 2.84 0.87 0.90 1.03 Elongation at break % 269 270 275 112 116 186 From the analysis of Table 1, it can be seen that the data of Examples 1-3 and Comparative Example 3 are similar before aging, and the difference in mechanical properties is not large, but the mechanical properties of Comparative Example 1-2 are worse than those of Example 1-3. After aging at 160°C and 24h, the mechanical properties of Examples 1-3 are almost unchanged, and there is a slight difference in Comparative Example 1-2, but the hardness of Comparative Example 3 is significantly increased, and the tensile strength and elongation at break are also changed. After aging at 300°C and 2h, the mechanical properties of Examples 1-3 are almost unchanged, and the mechanical properties of Comparative Example 1-3 are significantly decreased. Only one filler is added to Comparative Example 1-2. When the temperature rises to 300°C, the main chain of the silicone rubber is broken, thereby affecting the serious decline in mechanical properties and being in a state of loss. At 160°C, Comparative Example 3 has a large number of silanol groups in the side chain, which leads to an increase in hardness and makes the material brittle. When the temperature reaches 300°C, due to the serious aging of the side chain, the structural break of the main chain is affected, and the mechanical properties are on the verge of loss.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A vulcanized silicone rubber for automotive accessories, characterized in that: The vulcanized silicone rubber for automobile accessories comprises the following raw materials in parts by weight: 100-120 parts of raw rubber, 20-30 parts of modified white carbon black, 2-3 parts of filler, 0.5-1 part of coupling agent, 5-8 parts of crosslinking agent and 0.3-0.5 parts of catalyst.

2. The vulcanized silicone rubber for automobile accessories according to claim 1, characterized in that: The preparation method of the modified white carbon black comprises the following steps: (1) stirring white carbon black and water to form a suspension, then heating the suspension, adding a coupling agent and a surfactant to obtain a mixture; (2) The pH of the mixture is adjusted, and then the supernatant is removed by centrifugation, and the solid is dried to obtain modified silica.

3. The vulcanized silicone rubber for automobile accessories according to claim 2, characterized in that: In the step (1), the mass ratio of white carbon black, water, coupling agent and surfactant is 5-10:90-100:0.25-0.35:0.4-0.5, wherein the coupling agent is KH550 and the surfactant is sodium dodecyl sulfate.

4. The vulcanized silicone rubber for automobile accessories according to claim 2, characterized in that: The heating temperature in step (1) is 74-78° C., and the mixing time is 2-3 h.

5. The vulcanized silicone rubber for automobile accessories according to claim 2, characterized in that: In the step (2), the pH is 9-10, the rotation speed of the centrifugal separation is 500-800 r / min, and the temperature and time of the drying are 80-100° C. and 1-2 h, respectively.

6. A method for preparing the vulcanized silicone rubber for automobile accessories according to any one of claims 1 to 5, characterized in that: The preparation method of the vulcanized silicone rubber for automobile accessories is as follows: Add raw rubber and modified silica into a kneader and heat them. Then add filler, coupling agent, cross-linking agent and catalyst in sequence. Stir under vacuum and finally cool and discharge.

7. The method for preparing vulcanized silicone rubber for automobile accessories according to claim 6, characterized in that: The heating temperature and time are 180-190° C. and 1-2 hours respectively, and the filler is composed of nano silicon dioxide and nano titanium dioxide in a mass ratio of 1-2:

1.

8. The method for preparing vulcanized silicone rubber for automobile accessories according to claim 6, characterized in that: The coupling agent is γ-(ethylenediamino)propyltrimethoxysilane, the cross-linking agent is methyltriisopropenyloxysilane, the catalyst is tetramethylguanidinopropyltrimethoxysilane, and the vacuum pressure is -0.08~0.09MPa.