A semi-interpenetrating system of silicone rubber and butyl rubber, and its preparation method and application

Abstract

The present invention provides a method for preparing a semi-interpenetrating system of silicone rubber and butyl rubber. The semi-interpenetrating system prepared by the present invention can be used to improve the compatibility between silicone rubber and tackifying resins such as C5 resin, C9 resin, terpene resin, coumarone resin, rosin ester resin, hydrogenated rosin resin, and polymers such as polyisobutylene and polyisoprene, thereby improving the pressure-sensitive properties of the silicone rubber system and expanding the application range of silicone rubber as a sealing material. In addition, the system can be used to increase the room temperature cohesion of silicone rubber to prepare silicone rubber sealing strips, films, and other profiles. The preparation method is novel, efficient, has high product purity, and is simple to operate, making it suitable for industrial production.

Description

Technical Field

[0001] The invention relates to a semi-interpenetrating system of silicone rubber and butyl rubber, a preparation method and application thereof, and belongs to the technical field of rubber preparation and processing. Background Art

[0002] Silicone rubber exhibits excellent resistance to high and low temperatures, weathering, and ozone, but its inherent room-temperature pressure-sensitive properties are relatively poor, making it difficult to achieve high adhesion strength on substrates such as metals and plastics through its inherent pressure-sensitive properties. Tackifying resins such as C5 resin, C9 resin, terpene resin, and coumarone resin, as well as polymers such as polyisobutylene and polyisoprene, can significantly improve the initial adhesion of pressure-sensitive adhesives. However, these carbon-based polymers exhibit poor compatibility with silicone rubber systems, and significant phase separation occurs after mixing and storage for a period of time, impacting performance. Colloid Polym Sci (2008) 286:1257–1264) and Colloid Polym Sci (2010) 288:753–760 disclose improving the compatibility of silicone rubber and polyisobutylene by adding nanoparticles. However, this approach relies on the fact that the surface tension of the nanoparticles lies between the two polymer phases, potentially allowing them to adsorb at the interface and improve compatibility. Different polymers require different nanoparticle surface tensions, or require higher particle size and surface treatment. Therefore, improving the compatibility of silicone rubber and polyisobutylene is a major research challenge at this stage. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a method for preparing a semi-interpenetrating system of silicone rubber and butyl rubber. The semi-interpenetrating system prepared by the present invention can be used to improve the compatibility between silicone rubber and tackifying resins such as C5 resin, C9 resin, terpene resin, coumarone resin, rosin ester resin, hydrogenated rosin resin, and polymers such as polyisobutylene and polyisoprene, thereby improving the pressure-sensitive properties of the silicone rubber system and expanding the application range of silicone rubber as a sealing material. In addition, the system can be used to improve the room temperature cohesion of silicone rubber to prepare silicone rubber sealing strips, films and other profiles. The preparation method is novel, efficient, has high product purity, and is simple to operate, making it suitable for industrial production.

[0004] The technical solutions of the present invention are as follows:

[0005] A method for preparing a semi-interpenetrating system of silicone rubber and butyl rubber comprises the following steps:

[0006] 1) mixing butyl rubber, component A and plasticizer and kneading;

[0007] 2) adding silicone rubber to the mixed product of step 1) and mixing;

[0008] 3) adding a crosslinking agent to the product of step 2) and mixing to obtain a semi-interpenetrating system of silicone rubber and butyl rubber;

[0009] Wherein, the component A is selected from at least one of tackifying resin, polyisobutylene or polyisoprene;

[0010] The plasticizer is at least one of stearic acid, paraffin oil, polybutene, and polyisobutylene;

[0011] The cross-linking agent is selected from at least one of sulfur, tetrabenzylthiuram disulfide, zinc dibenzyldithiocarbamate, dibutylthiourea, N-cyclohexyl-2-benzothiazolesulfenamide, alkylphenol-formaldehyde resin, brominated alkylphenol-formaldehyde resin, and zinc oxide.

[0012] According to an embodiment of the present invention, the tackifying resin is selected from at least one of rosin ester resin, hydrogenated rosin resin, C5 resin, C9 resin, terpene resin, and coumarone resin.

[0013] According to an embodiment of the present invention, in step 1), mixing is carried out in an internal mixer, a kneader, or an open mixer.

[0014] The vinyl content of the butyl rubber in the above preparation method can be 0.8%-2.5%, specifically 1.05%, 1.15%, 1.7%, or 2.3%.

[0015] The relative molecular weight of the polyisobutylene in the above preparation method can be 1,000-100,000, specifically 1,300, 2,400, 35,000, 45,000, or 85,000.

[0016] In the above preparation method, the mixing temperature in step 1) can be 60-200°C, specifically 60°C, 100°C, or 140°C.

[0017] In the above preparation method, the mixing time in step 1) can be 1 to 60 hours, specifically 4 hours, 24 hours, or 48 hours.

[0018] In the above preparation method, the mass ratio of butyl rubber, component A and plasticizer in step 1) can be 1:0.02 to 1:0.001 to 0.1, for example, 1:0.1 to 0.5:0.001 to 0.1, specifically 1:0.1:0.01, 1:0.3:0.02, 1:0.5:0.05, 1:0.4:0.1, 1:0.2:0.02 or 1:0.125:0.005.

[0019] The silicone rubber in the above preparation method can be at least one of high-temperature vulcanized silicone rubber, vinyl silicone oil, and hydroxyl silicone oil.

[0020] According to an embodiment of the present invention, the mixing in step 2) is carried out in an internal mixer, a kneader, or an open mixer. In the above preparation method, the mixing temperature in step 2) can be 60-200°C, specifically 60°C, 100°C, or 140°C.

[0021] In the above preparation method, the mixing time in step 2) can be 0.5 to 24 hours, specifically 1 hour, 12 hours, or 24 hours.

[0022] In the above preparation method, the mass ratio of silicone rubber to butyl rubber can be 1:0.1-5, such as 1:0.1-3 or 1:0.5-2, specifically 1:0.1, 1:1, 1:3, 1:1.6.

[0023] In the above preparation method, the added amount of the crosslinking agent can be 1-5 wt% of the added amount of the butyl rubber, specifically 1 wt%, 3 wt%, 3.75 wt%, or 5 wt%.

[0024] According to an embodiment of the present invention, the mixing in step 3) is carried out in an internal mixer, a kneader, or an open mixer. In the above preparation method, the mixing temperature in step 3) can be 90-150°C, specifically 90°C, 100°C, or 120°C.

[0025] In the above preparation method, the mixing time in step 3) is 0.1-4 h, specifically 0.5 h, 1 h, or 1.5 h.

[0026] In the above preparation method, in step 3), the system is cooled to 90-150° C. before adding the cross-linking agent.

[0027] The present invention also provides a semi-interpenetrating system of silicone rubber and butyl rubber prepared by the above method.

[0028] The present invention also provides the use of the semi-interpenetrating system of silicone rubber and butyl rubber as a compatibilizer to increase the compatibility between silicone rubber and tackifying resin, polyisobutylene or polyisoprene; or added to silicone rubber to prepare silicone rubber sealing strips or films.

[0029] Beneficial effects

[0030] The present invention prepares a semi-interpenetrating system of silicone rubber and butyl rubber. This system can improve the compatibility between silicone rubber and polymers such as tackifying resins, polyisobutylene, or polyisoprene, and can also increase the room temperature cohesion of silicone rubber to prepare silicone rubber sealing strips, films, and other profiles. In addition, this system also has a certain improvement in its high-temperature resistance. Specifically, the preparation method of the present application has the following advantages:

[0031] 1) The method is novel, efficient, simple to operate, and easy to realize industrial production.

[0032] 2) The semi-interpenetrating system provided by this method can be prepared by an internal mixer, a kneader, a two-roll mixer, etc., with low equipment requirements and easy production.

[0033] 3) The system prepared by this method can effectively improve the compatibility between silicone rubber and carbon chain polymers, with obvious effects, greatly expanding the application range of silicone rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 .Test results of crosslink density of semi-interpenetrating system of silicone rubber and butyl rubber mixed at 100℃ for different times.

[0035] Figure 2 .Optical microscope photos of silicone rubber and polyisobutylene blends without and with different compatibilizers.

[0036] Figure 3 .TGA and DTG curves of silicone rubber and polyisobutylene blends without compatibilizer and with semi-interpenetrating system compatibilizer. DETAILED DESCRIPTION

[0037] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0038] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0039] In this application, "molecular weight" refers to relative molecular weight.

[0040] Example 1: Preparation of a Semi-Interpenetrating System of Silicone Rubber and Butyl Rubber

[0041] In a 2L kneader, add 500g of butyl rubber with a vinyl content of 1.15%, 200g of polyisobutylene with a molecular weight of 2400, and 50g of stearic acid. Heat to 120°C and mix for 24 hours. After uniform mixing, add 500g of high-temperature vulcanized silicone rubber and continue mixing at 120°C for 12 hours. After uniform mixing, cool to 100°C and add 15g of brominated alkylphenol-formaldehyde resin. After mixing for 0 min, 20 min, 40 min, 60 min, 80 min, 100 min, and 120 min, remove 20g of sample at each time for crosslink density testing.

[0042] Example 2: Preparation of a Semi-Interpenetrating System of Silicone Rubber and Butyl Rubber

[0043] In a 2L kneader, 500g of butyl rubber with a vinyl content of 1.15%, 100g of polyisobutylene with a molecular weight of 45,000, and 10g of stearic acid were added and mixed at 140°C for 12 hours. After uniform mixing, 800g of high-temperature vulcanized silicone rubber was added and mixed at 140°C for another 12 hours. After uniform mixing, the temperature was lowered to 120°C, and 30g of alkylphenol-formaldehyde resin was added. After mixing for 1 hour, the mixture was removed to obtain a semi-interpenetrating system of silicone rubber and butyl rubber.

[0044] Example 3: Preparation of a Semi-Interpenetrating System of Silicone Rubber and Butyl Rubber

[0045] In a 2L kneader, 800g of butyl rubber with a vinyl content of 1.15%, 100g of polyisobutylene with a molecular weight of 2400, and 4g of stearic acid were added and mixed at 140°C for 12 hours. After uniform mixing, 500g of high-temperature vulcanized silicone rubber was added and mixed at 140°C for another 12 hours. After uniform mixing, the temperature was lowered to 120°C, and 30g of alkylphenol-formaldehyde resin was added. After mixing for 2 hours, the mixture was removed to obtain a semi-interpenetrating system of silicone rubber and butyl rubber.

[0046] Example 4: Testing the crosslink density of the semi-IPS system by low-field nuclear magnetic resonance

[0047] The crosslinking density of the rubber samples mixed at different times taken out from Example 1 was tested by low-field nuclear magnetic resonance. Figure 1 As shown in Figure 3, as the mixing time at high temperature increases, the crosslinking density of the sample increases.

[0048] Example 5: Study on the improvement of compatibility of semi-interpenetrating system with silicone rubber and butyl rubber by optical microscopy

[0049] 100g of high temperature vulcanized silicone rubber and 10g of polyisobutylene with a molecular weight of 2400 were blended on a two-roll mixer, mixed evenly and taken out as sample 1. 1g of fumed silica was added to the above sample 1, mixed evenly and taken out as sample 2. 1g of the sample taken out in Example 2 was added to sample 1, mixed evenly and taken out as sample 3. The three samples were vacuumed at 60°C for 2h to remove internal bubbles, and then the phase separation was observed using an optical microscope. The test results are as follows: Figure 2 As shown. Figure 2 It can be seen that the addition of silica can improve the compatibility of the two phases, making the dispersed phase more regular and reducing its size. The semi-interpenetrating system prepared in Example 2 can further improve the compatibility between silicone rubber and polyisobutylene as a compatibilizer. The semi-interpenetrating system prepared in Example 2 is significantly more effective as a compatibilizer than silica.

[0050] Example 6: Testing the High-Temperature Resistance of Semi-IPS by TGA

[0051] The high temperature resistance of sample 1 without compatibilizer and sample 3 with semi-interpenetrating system as compatibilizer in Example 5 were tested by TGA and DTG. Figure 3 As shown in the figure, after adding the semi-IPS, the high-temperature resistance of polyisobutylene and silicone rubber in the blended sample has been improved to a certain extent compared to the system without adding the compatibilizer. It can be seen that the semi-IPS has a certain improvement on the high-temperature resistance of both materials.

[0052] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for preparing a semi-interpenetrating system of silicone rubber and butyl rubber, characterized in that: The steps include: 1) Mix butyl rubber with component A and plasticizer and then knead; 2) adding silicone rubber to the mixed product of step 1) and mixing; 3) adding a crosslinking agent to the product of step 2) and mixing to obtain a semi-interpenetrating system of silicone rubber and butyl rubber; Wherein, the component A is selected from at least one of tackifying resin, polyisobutylene or polyisoprene; The plasticizer is at least one of stearic acid, paraffin oil, polybutene, and polyisobutylene; The cross-linking agent is selected from at least one of sulfur, tetrabenzylthiuram disulfide, zinc dibenzyldithiocarbamate, dibutylthiourea, N-cyclohexyl-2-benzothiazolesulfenamide, alkylphenol-formaldehyde resin, brominated alkylphenol-formaldehyde resin, and zinc oxide; The tackifying resin is selected from at least one of rosin ester resin, hydrogenated rosin resin, C5 resin, C9 resin, terpene resin, and coumarone resin; The mass ratio of the butyl rubber, component A and plasticizer is 1:0.1~0.5:0.001~0.1; The mass ratio of the silicone rubber to the butyl rubber is 1:0.5-2; The amount of crosslinking agent added is 1-5wt% of the amount of butyl rubber added; The silicone rubber is high temperature vulcanized silicone rubber.

2. The preparation method according to claim 1, characterized in that The relative molecular weight of the polyisobutylene is 1,000-100,000.

3. The preparation method according to claim 1, characterized in that The mixing is carried out in an internal mixer, a kneader or an open mixer.

4. The preparation method according to claim 1, characterized in that The mixing temperature in steps 1) and 2) is 60-200°C; Step 3) The mixing temperature is 90~150℃.

5. The preparation method according to any one of claims 1 to 4, characterized in that The vinyl content of the butyl rubber is 0.8%-2.5%.

6. A semi-interpenetrating system of silicone rubber and butyl rubber prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the semi-interpenetrating system of silicone rubber and butyl rubber prepared by the preparation method according to any one of claims 1 to 5 as a compatibilizer to increase the compatibility between silicone rubber and tackifying resin, polyisobutylene or polyisoprene; Or, it can be added to silicone rubber to prepare silicone rubber sealing strips or films.

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