CN1261503C - A kind of silicone rubber composition and its preparation method and application - Google Patents

Abstract

The present invention relates to a silicon rubber composition which is prepared from raw silicon rubber, crosslinking agents, catalysts, filling materials and gamma-(3-acetylacetonyl)propyl-3-alkoxy silane. The present invention is prepared by mixing the components at a room temperature of 25 to 40 DEG C. The composition can be used for bonding metal. When the composition is bonded with the metal, gamma-(3-acetylacetonyl)propyl-3-alkoxy silane solution is coated on the surface of the metal to be pretreated; then the silicon rubber composition is coated on the surface of the metal. The gamma-(3-acetylacetonyl)propyl-3-alkoxy silane can generate chelate complexes on the surface of the metal. Thus, the bonding strength of silicon rubber and hard bonding metal is greatly increased, and the failure form is changed into cohesional failure from adhesive failure.

Description

A kind of silicone rubber composition and its preparation method and application

technical field

The invention relates to a silicone rubber composition and its preparation method and application. The composition is composed of silica gel, crosslinking agent, catalyst, filler and gamma-(3-acetylacetonyl)propyltrialkoxysilane. The composition is prepared by blending the above components at room temperature (25-40° C.). The composition can be used for bonding with metals.

Background technique

Silicone rubber has high and low temperature resistance, weather aging resistance and excellent electrical properties, and is an important bonding and sealing material. Silicone rubber is widely used in construction, transportation and electronic devices in modern industry. However, due to the low surface energy of silicone rubber, its bonding strength with metal surfaces, especially difficult-to-bond metals such as stainless steel and brass, is also very low, which affects the service life of many bonded and sealed parts. Therefore, it is of great practical significance to improve the bonding strength of silicone rubber, especially room temperature vulcanized silicone rubber and metal.

It is known to use a silane coupling agent to improve the bonding strength between an inorganic surface and an organic polymer. E.P.Plueddemann, the main researcher of silane coupling agents, made a systematic introduction to silane coupling agents in the monograph "Silane Coupling Agents" (Plenum, 1991, New York). The commonly used silane coupling agent molecules contain amino groups, epoxy groups, vinyl groups, acrylate groups, thiol groups, peroxide groups, etc. that can be combined with various resins; after hydrolysis of the alkoxy groups in the silane molecule Condenses with hydroxyl groups on the inorganic surface to form oxygen bridges. Therefore, the use of silane coupling agents to improve the adhesion of polymers to inorganic surfaces is usually very successful. However, because the Si-O-M (M represents a metal atom) bond is not resistant to hydrolysis, known silane coupling agents are not ideal for improving the bonding between silicone rubber and difficult-to-bond metals.

Contents of the invention

The silicone rubber composition of the present invention consists of raw silicon rubber, a crosslinking agent, a catalyst, a filler and γ-(3-acetylacetonyl)propyltrialkoxysilane. Its typical formula is as follows: Silica Gum Crosslinking Agent Catalyst Filler γ-(3-Acetylacetonyl) Propyl Trialkoxy Silane 100 parts by weight 2-10 parts by weight 0.2-2 parts by weight 3-100 parts by weight 1-5 parts by weight

The above-mentioned raw silicon rubber adopts commercially available raw silicon rubber, such as 107 silicon rubber, 108 silicon rubber, and the like. As the crosslinking agent, ethyl orthosilicate, methyl triacetoxysilane, methyl trimethyl ethyl ketone (wu) silane, methyl polysilazane and the like can be used. The catalyst can be dibutyltin dilaurate, stannous octoate, etc. Fillers can be white carbon black, calcium carbonate, titanium dioxide, zinc oxide, iron oxide, etc.

The structural formula of the aforementioned γ-(3-acetylacetonyl)propyl alkoxysilane is shown in formula (1). wherein R is an alkyl group containing 1-5 carbon atoms.

The silane, as a coupling agent, solves the problem of bonding room temperature vulcanized silicone rubber and difficult-to-bond metals. Experiments show that the acetylacetonate group can form a chelate (Formula 2) on the metal surface, so the use of a coupling agent containing this group can effectively improve the bonding strength between silicone rubber and metal. And change the form of failure from adhesive failure to cohesive failure.

According to the method of the present invention, γ-(3-acetylacetonate) propyl trialkoxysilane or its hydrolyzate 1-5% ethanol solution is coated on the metal surface and dried, and the metal surface is pretreated. deal with. The silicone rubber composition comprises 100 parts by weight of raw silicon rubber, 2 to 10 parts by weight of a crosslinking agent, 0.2 to 2 parts by weight of a catalyst, 3 to 100 parts by weight of a filler, γ-(3-acetylacetonate) propyl alkoxy It is prepared by blending 1-5 parts by weight of base silane at 25-40°C. Then the silicone rubber composition is coated on the treated metal surface for bonding.

The method of the invention is suitable for the bonding of commonly used metal materials such as steel and aluminum alloys and silicon rubber, and is also suitable for the bonding of difficult-to-bond metals such as stainless steel and brass and silicon rubber.

Adopting the method of the invention can effectively improve the bonding strength between the silicone rubber and the metal, and change the failure form from adhesion failure to cohesive failure. The shear strength measured by ASTM D1002-99 standard, the shear strength of silicone rubber and metal bonding can reach 2.46 ~ 2.95MPa.

Detailed ways

Below further illustrate characteristics of the present invention by embodiment.

Example 1

Prepare silicone rubber according to the following ratio: 107 Silica Gum (Beijing Chemical Plant) Ethyl Orthosilicate (Beijing Xinzhong Chemical Plant) Dibutyltin Dilaurate (Beijing Chemical Plant) No. 2 White Carbon Black (Shenyang Chemical Plant) Titanium Dioxide (Beijing Chemical Plant) γ-(3-Acetylacetonyl)propyltrimethoxysilane (homemade) 100 parts by weight 3 parts by weight 0.4 parts by weight 10 parts by weight 40 parts by weight 1 part by weight

1% gamma-(3-acetylacetonate) propyltrimethoxysilane ethanol solution was applied on the surface of 304# stainless steel and dried. After standing at room temperature for 24 hours, the stainless steel test piece was bonded with the above-mentioned silicone rubber. Place it at room temperature for 7 days to fully cure the silicone rubber. The shear strength test results are as follows: Shear strength Way of destruction 2.95MPa cohesive failure

Comparative example 1

Prepare silicone rubber according to the following ratio: 107 Silica Gum (Beijing Chemical Plant) Ethyl Orthosilicate (Beijing Xinzhong Chemical Plant) Dibutyltin Dilaurate (Beijing Chemical Plant) No. 2 White Carbon Black (Shenyang Chemical Plant) Titanium Dioxide (Beijing Chemical Plant) γ-(3-Acetylacetonyl)propyltrimethoxysilane (homemade) 100 parts by weight 3 parts by weight 0.4 parts by weight 10 parts by weight 40 parts by weight 0 parts by weight

The stainless steel test piece was bonded with the above-mentioned silicone rubber. Place it at room temperature for 7 days to fully cure the silicone rubber. The shear strength test results are as follows: Shear strength Way of destruction ＜0.5MPa Adhesion failure

Example 2

Prepare silicone rubber according to the following formula: 107 Silica Gum (Beijing Chemical Plant) Ethyl Orthosilicate (Beijing Xinzhong Chemical Plant) Dibutyltin Dilaurate (Beijing Chemical Plant) No. 2 White Carbon Black (Shenyang Chemical Plant) Titanium Dioxide (Beijing Chemical Plant) γ-(3-Acetylacetonyl)propyltrimethoxysilane (homemade) 100 parts by weight 3 parts by weight 0.4 parts by weight 10 parts by weight 40 parts by weight 1-5 parts by weight

The brass test piece was bonded with the above-mentioned silicone rubber. Place at room temperature for 24h, and treat at 100°C for 6h. The shear strength test results are as follows: Content of γ-(3-acetylacetonate)propyltrimethoxysilane (parts by weight) 0 1 3 5 Shear Strength (MPa) Failure Form ＜0.5 Adhesion failure 2.46 Cohesive Failure 2.79 Cohesive Failure 2.83 Cohesive Failure

Claims (9)

1. a silicone rubber composition, characterized in that the component content of the silicone rubber composition is as follows:                                                                                                   Link 2-10 weights Catalyst 0.2-2 parts by weight Filler 3-100 parts by weight   γ-(3-acetylacetonyl) propyltrialkoxysilane 1-5 parts by weight 2. according to the described silicon rubber composition of claim 1, it is characterized in that described silicon rubber is 107 silicon rubber. 3. The silicone rubber composition according to claim 1, characterized in that said crosslinking agent is tetraethyl orthosilicate. 4. The silicone rubber composition according to claim 1, wherein said catalyst is dibutyltin dilaurate. 5. The silicone rubber composition according to claim 1, characterized in that said filler is white carbon black and titanium dioxide. 6. according to the described silicone rubber composition of claim 1, it is characterized in that described γ-(3-acetylacetonate) propyl trialkoxysilane is γ-(3-acetylacetonate) propyltrimethoxy base silane. 7. according to the preparation method of the described silicone rubber composition of claim 1, it is characterized in that with 100 parts by weight of raw silicon rubber, 2～10 parts by weight of crosslinking agent, 0.2～2 parts by weight of catalyst, 3～100 parts by weight of filler , γ-(3-acetylacetonate) propyl alkoxysilane is prepared by blending 1-5 parts by weight at 25-40°C. 8. Use of the silicone rubber composition according to claim 1, characterized in that it improves the bonding of silicone rubber to metal materials. 9. The metal material according to claim 8, characterized in that said metal material is stainless steel and brass.