Quasi-constant modulus silicone rubber damping material and preparation method thereof

Abstract

The invention discloses a quasi-constant modulus silicone rubber damping material and a preparation method thereof. The method comprises the following steps: (1) preparing the following raw materials in parts by mass: 100 parts of silicone rubber; 10 to 80 parts of white carbon black; 0-10 parts of vinyl silicone oil; 0-1 part of iron oxide red; and 0.5-3 parts of a vulcanizing agent. And (2) mixing the raw materials in the step (1) on an open mill to prepare a rubber compound, standing the rubber compound at room temperature for more than 16 hours, remilling to obtain a rubber sheet blank with the thickness of 1-6mm, and carrying out compression molding and high-temperature post-treatment processes to prepare the quasi-constant modulus silicon rubber damping material. The quasi-constant modulus silicone rubber damping material prepared by the invention has the characteristics that the loss factor is not less than 0.25 in the range of-50 to 50 DEG C, the modulus change is small and the like, and is suitable for being used as a high-damping and quasi-constant modulus damping material.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber material production technology and relates to a quasi-constant modulus silicone rubber damping material and a preparation method thereof. Background Art

[0002] Silicone rubber is a special polymer material with silicon-oxygen chain segments as the main molecular chain. The Si-O-Si in the main chain is very flexible and can vary within the range of 130° to 180°, giving the silicone rubber main chain a high degree of flexibility. At the same time, the Si-O bond energy is about 451 kJ·mol -1 , which is much higher than the bond energy of CC chemical bonds of ordinary polymer materials (345 kJ·mol -1 ). The unique chemical main chain structure gives silicone rubber materials excellent low-temperature flexibility, high-temperature thermal stability, UV resistance and weather resistance, etc., making it widely used in aerospace, electronics, machinery and communications.

[0003] With the development of technology, the industry's technical requirements for silicone rubber damping materials and their products are getting higher and higher. During the operation of high-precision instruments and equipment, the vibration environment will have a significant impact on their accuracy, so the application of damping and vibration reduction products is particularly important. In particular, the requirements for the performance stability of silicone rubber damping materials in a wide temperature range are getting higher and higher, especially requiring that its elastic shear modulus change less to ensure that the equipment maintains a high degree of accuracy in the full temperature range. The peak loss factor of silicone rubber damping materials is in the viscoelastic range, and the elastic shear modulus of silicone rubber damping materials in this range changes significantly, which is not conducive to maintaining a quasi-constant shear elastic modulus.

[0004] To address this type of problem, it is often required that the glass transition temperature of the silicone rubber damping material be moved as far as possible towards the low temperature direction, so that the operating temperature range of the equipment is in the high elastic state range of the damping material, thereby obtaining a quasi-constant elastic shear modulus. However, when in the high elastic state range, the loss factor of the silicone rubber damping material is usually low, and the damping and vibration reduction effect is not good.

[0005] There are many factors that affect the damping performance of silicone rubber materials, mainly including the structure of silicone rubber molecular segments, surface modification of fillers, and the addition of damping agents. By introducing phenyl groups on the side chains of silicone rubber, the resistance of silicone rubber molecular segments during movement can be increased, energy dissipation can be improved, and thus the damping performance of the material can be improved; secondly, the introduction of phenyl groups will destroy the regularity of silicone rubber segments, basically eliminating the crystallization performance of silicone rubber, so that it can maintain the stability of structural performance in a wider temperature range; thirdly, vinyl silicone oil is a low molecular weight organic siloxane oligomer, which contains active vinyl groups in its molecules and can participate in the vulcanization and cross-linking of silicone rubber. Since low molecular weight silicone oil has good fluidity, its introduction can improve the flexibility of the vulcanization system on the one hand, thereby improving the flatness of the modulus of the damping material in a wide temperature range. On the other hand, the silicone oil molecules that are not fully involved in the vulcanization are suspended on the main chain of silicone rubber in the form of side chains, forming large-volume side groups, which increase the movement resistance of silicone rubber molecular segments and can improve the damping performance of the material. Summary of the invention

[0006] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and provide a quasi-constant modulus silicone rubber damping material and a preparation method thereof, wherein the obtained silicone rubber damping material has a significantly improved loss factor in the quasi-constant modulus region and has high damping performance within a wide temperature range.

[0007] The technical solutions provided by this application are as follows:

[0008] In the first aspect, the present application provides a quasi-constant modulus silicone rubber damping material, which includes the following raw materials, measured by mass: 100 parts of silicone rubber, 10 to 80 parts of white carbon black, 0 to 10 parts of vinyl silicone oil, 0 to 1 part of red iron oxide, and 0.5 to 3 parts of vulcanizer.

[0009] Furthermore, in terms of mass percentage, the vinyl content of the vinyl silicone oil is 8 to 15%.

[0010] Furthermore, the viscosity of the vinyl silicone oil at 25° C. is 100 to 250 mPa.s.

[0011] Furthermore, the silicone rubber is a phenyl silicone rubber with a phenyl content of 10% to 30%.

[0012] Furthermore, the white carbon black is fumed white carbon black.

[0013] In a second aspect, the present application also provides a method for preparing a quasi-constant modulus silicone rubber damping material, comprising:

[0014] Prepare raw materials according to mass proportions, including: 100 parts of silicone rubber, 10-80 parts of white carbon black, 0-10 parts of vinyl silicone oil, 0-1 part of red iron oxide, and 0.5-3 parts of vulcanizing agent;

[0015] On the open mill, add white carbon black, C-gel silicone oil and red iron oxide in turn for mixing, and finally add vulcanizing agent, roll and thin pass several times, and then produce sheets to obtain mixed rubber;

[0016] The mixed rubber is placed at room temperature for more than 16 hours, and after re-refining, a rubber sheet blank with a thickness of 1 to 6 mm is produced;

[0017] A rubber test piece is prepared using a rubber sheet blank, and the rubber test piece is vulcanized. The vulcanization conditions are as follows: the vulcanization temperature is between 110 and 160° C., and the vulcanization time is determined by the positive vulcanization time tested by a vulcanizer; a high-temperature two-stage vulcanization is performed to obtain a quasi-constant modulus silicone rubber damping material.

[0018] The present invention uses silicone rubber with a phenyl content of 10% to 30% as raw rubber, and uses the interaction of phenyl groups in the side chains of silicone rubber segments. On the one hand, the phenyl content is increased, the internal friction between segments, between segments and fillers, and between side chain groups is increased, energy dissipation is increased, and the loss factor in the quasi-constant modulus region of silicone rubber damping materials is improved; on the other hand, the introduction of phenyl groups destroys the regularity of silicone rubber molecular segments and eliminates the crystallinity of silicone rubber, thereby broadening the effective damping temperature range of silicone rubber; third, low molecular weight vinyl silicone oil is introduced to reduce the crosslinking density of the silicone rubber vulcanization system, improve the flexibility of the vulcanization system, and enhance the flatness of the modulus of the damping material in a wide temperature range. On the other hand, the silicone oil molecules that are not fully involved in the vulcanization are suspended on the main chain of the silicone rubber in the form of side chains to form large-volume side groups, thereby further increasing the internal friction between silicone rubber segments, between segments and fillers, and between side chain groups, thereby further enhancing the damping performance of the material. The quasi-constant modulus temperature range of silicone rubber damping materials is broadened through the above approach.

[0019] In summary, this application at least includes the following beneficial technical effects:

[0020] The silicone rubber damping material prepared by the present invention utilizes the interaction of phenyl groups in the side chains of silicone rubber segments to broaden the quasi-constant modulus temperature range of the silicone rubber damping material, and at the same time improves the loss factor within the quasi-constant modulus temperature range. The present invention has many advantages such as simple operation and strong material designability, and has broad application prospects in the field of high-precision instrument damping and vibration reduction.

[0021] The quasi-constant modulus silicone rubber damping material prepared by the invention has a loss factor of not less than 0.25 within the range of -50 to 50° C. and a small change in shear elastic modulus. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Figure a is the elastic shear modulus-temperature curve of Example 1, and Figure b is the loss factor-temperature curve of Example 1;

[0023] Figure 2 Figure a is the elastic shear modulus-temperature curve of Example 2, and Figure b is the loss factor-temperature curve of Example 2;

[0024] Figure 3 Figure a is the elastic shear modulus-temperature curve of Example 3, and Figure b is the loss factor-temperature curve of Example 3;

[0025] Figure 4 Figure a is the elastic shear modulus-temperature curve of Example 4, and Figure b is the loss factor-temperature curve of Example 4;

[0026] Figure 5 Figure a is the elastic shear modulus-temperature curve of the comparative example, and Figure b is the loss factor-temperature curve of the comparative example. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be described in further detail below.

[0028] In the following examples, the mass content of vinyl in the vinyl silicone oil is 8-15%, and the viscosity of the vinyl silicone oil at 25° C. is 100-250 mPa.s. The silicone rubber is a phenyl silicone rubber with a phenyl content of 10%-30%. The white carbon black is fumed white carbon black.

[0029] Example 1

[0030] (I) Prepare the following raw materials

[0031] Silicone rubber 100 parts

[0032] 40 parts of white carbon black

[0033] 3 parts of vinyl silicone oil

[0034] 0.5 parts of red iron oxide

[0035] 1.5 parts of vulcanizing agent

[0036] (ii) refining the silicone rubber on an open mixing mill, adding white carbon black, silicone oil and red iron oxide in sequence for mixing, and finally adding a vulcanizing agent, rolling and thinning the rubber several times before producing a sheet to obtain a mixed rubber.

[0037] (3) The mixed rubber is placed at room temperature for more than 16 hours, and after re-refining, a 6 mm thick rubber sheet blank is produced.

[0038] (iv) A rubber test piece is prepared using the rubber sheet blank, and the rubber test piece is vulcanized at a vulcanization temperature of 116° C. for a vulcanization time of 20 min to obtain a vulcanized rubber test piece.

[0039] (V) After vulcanization, the rubber specimen is kept in an oven at 200°C for 4 hours for two-stage vulcanization to prepare a quasi-constant modulus silicone rubber damping material.

[0040] (VI) The quasi-constant modulus silicone rubber damping material obtained in this embodiment has a shear elastic modulus of 2.67 MPa to 14.8 MPa in the temperature range of -50°C to 50°C, a shear elastic modulus variation of no more than one order of magnitude in the entire temperature range, and a loss factor of ≮0.25. The results are shown in the attached Figure 1 .

[0041] Example 2

[0042] (I) Prepare the following raw materials

[0043] Silicone rubber 100 parts

[0044] 40 parts of white carbon black

[0045] 5 parts of vinyl silicone oil

[0046] 0.5 parts of red iron oxide

[0047] 1.5 parts of vulcanizing agent

[0048] (ii) refining the silicone rubber on an open mixing mill, adding white carbon black, silicone oil and red iron oxide in sequence for mixing, and finally adding a vulcanizing agent, rolling and thinning the rubber several times before producing a sheet to obtain a mixed rubber.

[0049] (3) The mixed rubber is placed at room temperature for more than 16 hours, and after re-refining, a 6 mm thick rubber sheet blank is produced.

[0050] (iv) A rubber test piece is prepared using the rubber sheet blank, and the rubber test piece is vulcanized at a vulcanization temperature of 116° C. for a vulcanization time of 20 min to obtain a vulcanized rubber test piece.

[0051] (V) After vulcanization, the rubber specimen is kept in an oven at 200°C for 4 hours for two-stage vulcanization to prepare a quasi-constant modulus silicone rubber damping material.

[0052] (VI) The quasi-constant modulus silicone rubber damping material obtained in this embodiment has a shear elastic modulus of 1.4 MPa to 8 MPa in the temperature range of -50°C to 50°C, a shear elastic modulus variation of no more than one order of magnitude in the entire temperature range, and a loss factor of ≮0.25. The results are shown in the attached Figure 2 .

[0053] Example 3

[0054] (I) Prepare the following raw materials

[0055] Silicone rubber 100 parts

[0056] 40 parts of white carbon black

[0057] 8 parts of vinyl silicone oil

[0058] 0.5 parts of red iron oxide

[0059] 1.5 parts of vulcanizing agent

[0060] (ii) refining the silicone rubber on an open mixing mill, adding white carbon black, silicone oil and red iron oxide in sequence for mixing, and finally adding a vulcanizing agent, rolling and thinning the rubber several times before producing a sheet to obtain a mixed rubber.

[0061] (3) The mixed rubber is placed at room temperature for more than 16 hours, and after re-refining, a 6 mm thick rubber sheet blank is produced.

[0062] (iv) A rubber test piece is prepared using the rubber sheet blank, and the rubber test piece is vulcanized at a vulcanization temperature of 116° C. for a vulcanization time of 20 min to obtain a vulcanized rubber test piece.

[0063] (V) After vulcanization, the rubber specimen is kept in an oven at 200°C for 4 hours for two-stage vulcanization to prepare a quasi-constant modulus silicone rubber damping material.

[0064] (VI) The quasi-constant modulus silicone rubber damping material obtained in this embodiment has a shear elastic modulus of 0.46 MPa to 1.83 MPa in the temperature range of -50°C to 50°C, a shear elastic modulus variation of no more than one order of magnitude in the entire temperature range, and a loss factor of ≮0.25. The results are shown in the attached Figure 3 .

[0065] Example 4

[0066] Step 1: Prepare the following raw materials by weight:

[0067]

[0068] Step (ii): the silicone rubber is refined on an open mill, white carbon black, silicone oil and red iron oxide are added in sequence for mixing, and finally a vulcanizing agent is added, and the mixed rubber is obtained after rolling and thinning for several times.

[0069] (3) The mixed rubber is placed at room temperature for more than 16 hours, and after re-refining, a 6 mm thick rubber sheet blank is produced.

[0070] (iv) A rubber test piece is prepared using the rubber sheet blank, and the rubber test piece is vulcanized at a vulcanization temperature of 116° C. for a vulcanization time of 20 min to obtain a vulcanized rubber test piece.

[0071] (V) After vulcanization, the rubber specimen is kept in an oven at 200°C for 4 hours for two-stage vulcanization to prepare a quasi-constant modulus silicone rubber damping material.

[0072] (VI) The quasi-constant modulus silicone rubber damping material obtained in this embodiment has a shear elastic modulus of 2.3 MPa to 17.7 MPa in the temperature range of -50°C to 50°C, a shear elastic modulus change of no more than one order of magnitude in the entire temperature range, and a loss factor of ≮0.25. The results are shown in the attached Figure 4 .

[0073] Comparative Example

[0074] Step 1: Prepare the following raw materials by weight:

[0075] Silicone rubber 100 parts

[0076] 40 parts of white carbon black

[0077] Vinyl silicone oil 0 parts

[0078] 0.5 parts of red iron oxide

[0079] 1.5 parts of vulcanizing agent

[0080] Step (ii): the silicone rubber is refined on an open mill, white carbon black, silicone oil and red iron oxide are added in sequence for mixing, and finally a vulcanizing agent is added, and the mixed rubber is obtained after rolling and thinning for several times.

[0081] (3) The mixed rubber is placed at room temperature for more than 16 hours, and after re-refining, a 6 mm thick rubber sheet blank is produced.

[0082] (iv) A rubber test piece is prepared using the rubber sheet blank, and the rubber test piece is vulcanized at a vulcanization temperature of 116° C. for a vulcanization time of 20 min to obtain a vulcanized rubber test piece.

[0083] (V) After vulcanization, the rubber test piece is kept in an oven at 200°C for 4 hours for two-stage vulcanization to prepare a comparative example sample.

[0084] (VI) The performance of the comparative example was characterized. The shear modulus was 3.10 MPa to 44.9 MPa in the temperature range of -50°C to 50°C, the shear modulus varied by more than one order of magnitude in the entire temperature range, and the temperature range of the loss factor ≮0.25 was -60°C to -7.4°C.

[0085] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0086] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A quasi-constant modulus silicone rubber damping material, characterized in that: Calculated by mass, the raw materials include: 100 parts of silicone rubber, 10-80 parts of white carbon black, 0-10 parts of vinyl silicone oil, 0-1 part of red iron oxide, and 0.5-3 parts of vulcanizing agent.

2. The quasi-constant modulus silicone rubber damping material according to claim 1, characterized in that: Calculated by mass percentage, the vinyl content of the vinyl silicone oil is 8-15%.

3. The quasi-constant modulus silicone rubber damping material according to claim 1, characterized in that: The viscosity of the vinyl silicone oil at 25° C. is 100 to 250 mPa.s.

4. The quasi-constant modulus silicone rubber damping material according to claim 1, characterized in that: The silicone rubber is phenyl silicone rubber with a phenyl content of 10% to 30%.

5. The quasi-constant modulus silicone rubber damping material according to claim 1, characterized in that: The white carbon black is fumed white carbon black.

6. A method for preparing a quasi-constant modulus silicone rubber damping material according to any one of claims 1 to 5, characterized in that: include: Prepare raw materials according to mass proportions, including: 100 parts of silicone rubber, 10-80 parts of white carbon black, 0-10 parts of vinyl silicone oil, 0-1 part of red iron oxide, and 0.5-3 parts of vulcanizing agent; On the open mill, add white carbon black, C-gel silicone oil and red iron oxide in turn for mixing, and finally add vulcanizing agent, roll and thin pass several times, and then produce sheets to obtain mixed rubber; The mixed rubber is placed at room temperature for more than 16 hours, and after re-refining, a rubber sheet blank with a thickness of 1 to 6 mm is obtained; a rubber test piece is prepared using the rubber sheet blank, and the rubber test piece is vulcanized under the vulcanization conditions: the vulcanization temperature is 110 to 160° C., and the vulcanization time is determined by the positive vulcanization time tested by the vulcanizer; a high-temperature two-stage vulcanization is performed to obtain a quasi-constant modulus silicone rubber damping material.

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