Dealcoholized silicone rubber and preparation method thereof

Abstract

The invention provides dealcoholized silicone rubber and a preparation method thereof, and belongs to the technical field of high polymer materials. The dealcoholized silicone rubber comprises the following components in parts by mass: 100 parts of a base material polymer, 5-30 parts of a reinforcing filler, 3-8 parts of a cross-linking agent, 0.001-1 part of a catalyst and 0.2-3 parts of an auxiliary agent. According to the preparation method, isocyanate methyl trimethoxy silane and the like are adopted as cross-linking agents, amino silane or amino silicon oil is adopted as a catalyst, cross-linking curing is carried out in an autocatalysis mode, a traditional titanium catalyst or an organic tin catalyst is not used, and therefore it is guaranteed that the dealcoholized silicone rubber obtained through the technical scheme is non-toxic and harmless; and the problem of viscosity peak does not occur in the production process, so that the actual demand is met.

Description

Technical Field

[0001] The present invention specifically relates to a de-alcoholized silicone rubber and a preparation method thereof, belonging to the technical field of polymer materials. Background Art

[0002] At present, the preparation processes of de-alcoholized silicone rubber mainly fall into two categories: one category is based on hydroxyl-terminated polydimethylsiloxane as the base polymer, alkoxysilane as the cross-linking agent, and titanate or titanate complex as the catalyst. The first two are catalytically cross-linked into a network structure and cured. For this type of alcohol-based silicone rubber, due to the use of a titanium catalyst, a viscosity peak is likely to occur during the product production process, which brings great inconvenience to the production process. At the same time, it will also cause problems such as yellowing and discoloration during the later use of the product. And the cross-linking system containing an organotin catalyst has toxicity problems, and the use of organotin in silicone rubber has been prohibited by the European Union. For example, in the prior art CN103642451A, "Room Temperature Vulcanized One-Component De-Alcoholized Silicone Rubber Sealant and Preparation Method Thereof" is disclosed. Although it specifically records that "including: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 10 - 30 parts of dimethyl silicone oil, 5 - 10 parts of cross-linking agent, 1 - 5 parts of silane coupling agent, 50 - 150 parts of reinforcing filler, 0.5 - 3 parts of catalyst, 0.5 - 2 parts of storage stabilizer", it uses a titanium catalyst, and thus there is a problem of viscosity peak during the production process, which will bring great inconvenience to the production process. In addition, in CN107573698A, "A Two-Component Room Temperature Vulcanized De-Alcoholized Silicone Rubber and Preparation Method Thereof" is disclosed. However, on the one hand, it uses an organotin catalyst, and organotin catalysts are toxic and have been prohibited by the European Union. On the other hand, this technical solution is a two-component system that needs to be premixed in advance, and thus there are problems such as cumbersome processes.

[0003] The other category is to use α-silane as the cross-linking agent or catalyst and cross-link and cure in a self-catalyzed manner. However, the prepared de-alcoholized silicone rubber product has problems of yellowing and discoloration during the later use process.

[0004] Therefore, there is a need for a non-toxic and harmless de-alcoholized silicone rubber that does not have a viscosity peak problem during the production process and does not turn yellow or discolor during the later use of the product. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a de-alcoholized silicone rubber and a preparation method thereof. Among them, isocyanate group methyltrimethoxysilane and the like are used as cross-linking agents, and amino silane or amino silicone oil is used as the catalyst, and cross-linking and curing are carried out in a self-catalyzed manner, avoiding the use of traditional titanium catalysts or organotin catalysts, thereby ensuring that the de-alcoholized silicone rubber obtained by this technical solution is non-toxic and harmless and does not have a viscosity peak problem during the production process to meet the actual needs.

[0006] To achieve the above technical objectives, the following technical solutions are proposed: The first objective of this technical solution is to provide a de-alcoholic silicone rubber, which, by mass fraction, comprises the following components: 100 parts of a base polymer, 5 - 30 parts of a reinforcing filler, 3 - 8 parts of a crosslinking agent, 0.001 - 1 part of a catalyst, and 0.2 - 3 parts of an auxiliary agent; Further, the base polymer is a hydroxyl-terminated methyl polysiloxane with a viscosity of 400 - 100000 cs. If the viscosity is too low, the mechanical properties of the product will be poor and it will have no practical application value; if the viscosity is too high, the operability of the production process involved will be poor.

[0007] Further, the crosslinking agent is one or any mixture of two or more of isocyanate group methyltrimethoxysilane, isocyanate group methyltriethoxysilane, and isocyanate group methyltripropoxysilane. The definition of this crosslinking agent ensures that the preparation of this de-alcoholic silicone rubber crosslinks and cures in a self-catalytic manner, thereby avoiding problems such as toxicity and harm caused by traditional catalysts (titanium catalysts or organotin catalysts) and the appearance of viscosity peaks during the production process.

[0008] Further, the catalyst is an amino silane or an amino silicone oil. Among them, the amino silane is one or any mixture of two or more of N,N-diethylmethyltriethoxysilane, N,N-dimethylmethyltriethoxysilane, N,N-diethylmethyltrimethoxysilane, N,N-dimethylmethyltriethoxysilane, and 3-aminopropyltriethoxysilane; the viscosity of the amino silicone oil does not exceed 100 cs. If the viscosity is too large, the molecular weight is large and the activity is low, which does not conform to the production process design. This catalyst is used for curing and crosslinking into an elastomer.

[0009] Further, the auxiliary agent is a silane coupling agent.

[0010] Further, the reinforcing filler includes white carbon black, quartz powder, or nano calcium carbonate.

[0011] The second objective of this technical solution is to provide a preparation method of a de-alcoholic silicone rubber, which includes: weighing a base polymer with a viscosity of 400 - 100000 cs and a reinforcing filler, mixing them evenly, and performing kneading treatment at 150 - 180 °C; cooling and vacuum degassing; adding a crosslinking agent and mixing evenly under closed conditions; then adding a catalyst and mixing evenly under closed conditions, and packaging for standby.

[0012] Among them, preferably, the reinforcing filler is white carbon black with a specific surface area of 200 m 2 / g after surface treatment and modification.

[0013] Adopting this technical solution brings the following beneficial technical effects: In the present invention, an α,ω-hydroxy-terminated polydimethylsiloxane is used as the base polymer, an isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane or isocyanatomethyltripropoxysilane is used as the crosslinking agent, an aminosilane or amino silicone oil is used as the catalyst, and a reinforcing filler such as fumed silica (or quartz powder, nano calcium carbonate) is used to obtain a non-alcohol releasing silicone rubber. Compared with traditional alcohol-based silicone rubbers, it has no viscosity peak of the non-alcohol releasing type, no toxicity of titanium catalysts or / and organotin catalysts, and eliminates the problem of easy yellowing and discoloration of the traditional α-silane self-catalytic system; In addition, the combinations of components involved in the present invention can not only obtain a non-toxic and harmless product without viscosity peak problems during production and no yellowing or discoloration during later use of the product, but also ensure the operability and stability of the product preparation process. Detailed implementation manners

[0014] The technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0015] Embodiment 1 Take 100 g of α,ω-hydroxy-terminated polydimethylsiloxane with a viscosity of 3500 cs, add 20 g of fumed silica with a specific surface area of 200 m 2 / g that has been surface-treated and modified, mix evenly, perform high-temperature kneading treatment at 150 °C, cool down (naturally), and remove bubbles (vacuum degassing); add isocyanatomethyltrimethoxysilane, mix evenly under closed conditions, then add N,N-diethylmethyltriethoxysilane, continue to mix evenly under closed conditions, and then package for standby.

[0016] Embodiment 2 Take 100 g of α,ω-hydroxy-terminated polydimethylsiloxane with a viscosity of 10000 cs, add 20 g of fumed silica with a specific surface area of 200 m 2 / g that has been surface-treated and modified, mix evenly, perform high-temperature kneading treatment at 180 °C, cool down (naturally), and remove bubbles (vacuum degassing). Add isocyanatomethyltriethoxysilane, mix evenly under closed conditions, then add 3-aminopropyltriethoxysilane, continue to mix evenly under closed conditions, and then package for standby.

[0017] Embodiment 3 Take 100 g of α,ω-hydroxy-terminated polydimethylsiloxane with a viscosity of 20000 cs, add 20 g of fumed silica with a specific surface area of 200 m 220 g of fumed silica per g, mix evenly, perform high-temperature kneading treatment at 160 °C, cool down (naturally), and remove bubbles (vacuum degassing). Add isocyanatomethyltripropoxysilane, mix evenly under sealed conditions, then add amino silicone oil with a viscosity of 20 cs, continue to mix evenly under sealed conditions, and then package for standby.

[0018] Example 4 Take 100 g of hydroxyl-terminated polydimethylsiloxane with a viscosity of 3500 cs, add 20 g of fumed silica with a surface area of 200 m 2 per g that has been surface-treated and modified, mix evenly, perform high-temperature kneading treatment at 180 °C, cool down (naturally), and remove bubbles (vacuum degassing). Add isocyanatomethyltrimethoxysilane, mix evenly under sealed conditions, then add N,N-diethylpropyltrimethoxysilane, continue to mix evenly under sealed conditions, and then package for standby.

[0019] Example 5 Take 100 g of hydroxyl-terminated polydimethylsiloxane with a viscosity of 3500 cs, add 20 g of fumed silica with a surface area of 200 m 2 per g that has been surface-treated and modified, mix evenly, perform high-temperature kneading treatment at 170 °C, cool down (naturally), and remove bubbles (vacuum degassing). Add isocyanatomethyltrimethoxysilane, mix evenly under sealed conditions, then add N,N-diethylpropyltrimethoxysilane, continue to mix evenly under sealed conditions, and then package for standby.

[0020] Example 6 Take 100 g of hydroxyl-terminated polydimethylsiloxane with a viscosity of 3500 cs, add 20 g of fumed silica with a surface area of 200 m 2 per g that has been surface-treated and modified, mix evenly, perform high-temperature kneading treatment at 150 °C, cool down (naturally), and remove bubbles (vacuum degassing). Add isocyanatomethyltrimethoxysilane, mix evenly under sealed conditions, then add N,N-diethylpropyltrimethoxysilane, continue to mix evenly under sealed conditions, and then package for standby.

[0021] On the basis of Examples 1-6, perform performance tests on the alcohol-free silicone rubber products obtained from Examples 1-6, and the results are shown in Table 1 below.

[0022] As described above, it is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A de-alcoholized silicone rubber, characterized in that it comprises the following components in parts by mass: 100 parts of a base polymer, 5 - 30 parts of a reinforcing filler, 3 - 8 parts of a crosslinking agent, 0.001 - 1 part of a catalyst, and 0.2 - 3 parts of an auxiliary agent.

2. The de-alcoholized silicone rubber according to claim 1, characterized in that the base polymer is a hydroxyl-terminated methyl polysiloxane with a viscosity of 400 - 100000 cs.

3. The de-alcoholized silicone rubber according to claim 1, characterized in that the crosslinking agent is one or any mixture of two or more of isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane, and isocyanatomethyltripropoxysilane.

4. The de-alcoholized silicone rubber according to claim 1, characterized in that the catalyst is an aminosilane or an amino silicone oil, wherein the aminosilane is one or any mixture of two or more of N,N-diethylmethyltriethoxysilane, N,N-dimethylmethyltriethoxysilane, N,N-diethylmethyltrimethoxysilane, N,N-dimethylmethyltriethoxysilane, and 3-aminopropyltriethoxysilane.

5. The de-alcoholized silicone rubber according to claim 1 or 4, characterized in that the catalyst is an amino silicone oil with a viscosity not exceeding 100 cs.

6. The de-alcoholized silicone rubber according to claim 1, characterized in that the auxiliary agent is a silane coupling agent.

7. The de-alcoholized silicone rubber according to claim 1, characterized in that the reinforcing filler includes fumed silica, quartz powder, or nano calcium carbonate.

8. A preparation method of a de-alcoholized silicone rubber, characterized in that it includes: weighing a base polymer with a viscosity of 400 - 100000 cs and a reinforcing filler, mixing evenly, and performing a kneading treatment at 150 - 180 °C; cooling and degassing under vacuum; adding a crosslinking agent and mixing evenly under a closed condition; then adding a catalyst and mixing evenly under a closed condition, packaging, and storing for later use.

9. The preparation method of the de-alcoholized silicone rubber according to claim 8, characterized in that The reinforcing filler is silica with a specific surface area of 200 m 2 / g after surface treatment and modification.

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