KR101729993B1 - Heat-vulcanizable silicon sponge rubber composition having uniformeded anc closed cell, process for the preparation thereof and sponge rubber product produced therefrom - Google Patents

Abstract

The present invention relates to a thermosetting silicone sponge rubber composition, a process for producing the same, and a sponge rubber product obtained therefrom. The thermosetting silicone sponge rubber composition is obtained by blending a vinyl group-containing polyorganosiloxane silicone gum with a reinforcing silica having a large specific surface area and a silicon-based processing aid having a functional group at the terminal. The polyorganosiloxane- Or when a polyorganohydrogensiloxane containing a hydrogen group in a side chain is cured by an addition reaction in the presence of a platinum catalyst, a uniform and closed cell can be formed by using moisture generated by a dehydration reaction.

Description

TECHNICAL FIELD [0001] The present invention relates to a thermosetting silicone sponge rubber composition having uniform and closed cells, a process for producing the same, and a sponge rubber product produced therefrom. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a thermosetting silicone sponge rubber composition,

The present invention relates to a thermosetting silicone sponge rubber composition, a process for producing the same, and a sponge rubber product produced therefrom. The thermosetting silicone sponge rubber composition is obtained by blending a vinyl group-containing polyorganosiloxane silicone gum with a reinforcing silica having a large specific surface area and a silicon-based processing aid having a functional group at the terminal. The polyorganosiloxane- Or when a polyorganohydrogensiloxane containing a hydrogen group in a side chain is cured by an addition reaction in the presence of a platinum catalyst, a uniform and closed cell can be formed by using moisture generated by a dehydration reaction.

Conventionally, a thermosetting silicone sponge rubber product can be obtained by curing a silicone rubber composition with an organic foaming agent and an organic peroxide vulcanization agent, and various foams are formed depending on the kind and content of the silicone sponge rubber composition and the organic foaming agent And the foam thus formed can be applied to various uses.

Usually, the organic foaming agent used in the silicone sponge rubber forms a silicone rubber foam as an azo compound by using nitrogen gas generated during thermal curing. Azoisobutyronitrile (AIBN) (CAS # 78-82-0), which is mainly used at this time, generates tetramethyl succinonitrile (TMSN) (CAS # 3333-52-6) which is an environmentally harmful substance as a side reaction product . Other blowing agents such as azodicarbamide (ADCA) (CAS # 123-77-3), dinitrosopentamethylene (DNPT) (CAS # 101-25-7) are known to be relatively less harmful. However, these foaming agents tend to be classified as a substance to be regulated due to problems such as poor foaming effect and unpleasant odor.

Korean Patent Laid-Open Publication No. 2001-0092410 (A) discloses a method of forming a foamed product by using the thermoplastic resin hollow powder together with water-soluble silicone without using the organic-based foaming agent and using the expansion of the inert gas captured by the resin during the curing reaction / RTI > However, the method of applying the resin hollow powder, which is a thermoplastic resin, has a problem in the possibility of discoloration and stability due to heat, and has a limitation in that it can not be used because of high commercialization due to high raw material cost.

Korean Patent Publication No. 2001-0092410 (A)

It is a technical object of the present invention to overcome the problems of the prior art by providing a silicone sponge rubber composition having uniform and closed cells free from discoloration by heat after curing without generating harmful decomposition products during production of the silicone sponge rubber do.

A first aspect of the present invention is a composition comprising (a) 100 parts by weight of a mixture of a methylvinyl polyorganosiloxane gum and a hydroxyl polyorganosiloxane gum; (B) 10 to 100 parts by weight of a reinforcing silica having a specific surface area of 150 m ² / g or more as a filler, based on 100 parts by weight of the component (a); (c) 0.5 to 20 parts by weight of a silicone-based processing aid having a terminal functional group; (d) 1 to 10 parts by weight of a polyorganohydrogensiloxane containing a hardening group at its terminal or side chain; (e) 1 to 10 parts by weight of a stabilizer containing not less than 95% of soda lime borosilicate; (f) 0.001 to 1 part by weight of a platinum catalyst; And (g) 0.001 to 0.5 parts by weight of a hardening retardant.

The second aspect of the present invention is characterized in that in the first aspect, the polyorganosiloxane silicone gum has a viscosity at 25 DEG C of 10,000,000 cPs or more and a repeating unit represented by the formula R _a SiO _{(4-a) / 2} , Wherein R is an aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group having 1 to 10 carbon atoms or an aromatic unsaturated hydrocarbon group having 6 to 30 carbon atoms and a has a value of 1.90 to 2.05 .

A third aspect of the present invention relates to a thermosetting silicone sponge rubber composition in which in the first aspect the reinforcing silica is a wet silica having an average particle size of 9.5 to 1412 占 퐉 and a specific gravity of 1.9 to 2.2 g / .

A fourth aspect of the present invention is the thermosetting silicone sponge rubber composition according to the first aspect, wherein the silicone-based processing aid is a polyorganosiloxane polymer having a viscosity at 25 캜 of not more than 100 cPs and having a structure represented by the following formula will be.

In Formula 1,

R ¹ , R ² , R ³ and R ⁴ are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a vinyl group and a phenyl group;

Y is O, NH or NR ⁶ , wherein R ⁶ is an alkyl group having 1 to 10 carbon atoms;

R ⁵ is hydrogen or an alkyl group having 1 to 10 carbon atoms;

and n is an integer of 1 to 25. [

A fifth aspect of the present invention relates to the thermosetting silicone sponge rubber composition, wherein the polyorganohydrogen siloxane in the first aspect has a structure represented by the following formula (2).

In Formula 2,

R, R ¹ and R ² are, independently of each other, an aliphatic saturated hydrocarbon, aliphatic unsaturated hydrocarbon, or aromatic hydrocarbon;

m and n are each independently an integer of 10 to 100;

A sixth aspect of the present invention relates to a thermosetting silicone sponge rubber composition wherein, in the fifth aspect, R, R ¹ and R ² are each independently selected from the group consisting of methyl, ethyl, butyl and aryl groups.

A seventh aspect of the present invention relates to the thermosetting silicone sponge rubber composition according to the first aspect, wherein the stabilizer has a true specific gravity of 0.1 to 1.0 g / cc and a particle size of 500 mu m or less.

An eighth aspect of the present invention relates to the thermosetting silicone sponge rubber composition, wherein the stabilizer in the seventh aspect has an average particle size of 150 to 200 탆.

In a ninth aspect of the present invention, in the first aspect, the platinum catalyst is a thermosetting silicone sponge rubber which forms a complex with a low molecular weight vinylsiloxane and has an oxidation number of 0 and a platinum content of 0.5 to 15% ≪ / RTI >

The tenth aspect of the present invention relates to a thermosetting silicone sponge rubber composition wherein the content of the platinum catalyst in the first aspect is 0.1 to 0.5 parts by weight.

An eleventh aspect of the present invention relates to a thermosetting silicone sponge composition, wherein the curing retarder in the first aspect has a double bond or triple bond containing an alkenyl group.

In a twelfth aspect of the present invention, in the first aspect, the hardening retarder is selected from the group consisting of 1-ethynyl-1-cyclohexanol, 1,1,3,3-tetramethyl-1,3-divinyldisilazane , 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 2-methyl-3-butyn-2-ol and phosphite-based retardants Based on the total weight of the thermosetting silicone sponge composition.

A thirteenth aspect of the present invention relates to a thermosetting silicone sponge rubber composition wherein the content of the curing retardant in the first aspect is 0.1 to 0.5 parts by weight.

A fourteenth aspect of the present invention is a method for manufacturing a semiconductor device comprising the steps of: (1) pre-mixing polyorganosiloxane silicon gums into a kneader; (2) introducing into the kneader a reinforcing silica having a specific surface area of 150 m ² / g or more as a filler and a silicone-based processing aid having a functional group at the terminal; (3) stirring and dispersing the mixture from the step (2); And (4) further adding a silicon-based processing aid having a functional group at the end to the kneader and stirring the mixture at an elevated temperature; (5) adding a polyorganohydrogen siloxane, a stabilizer, a platinum catalyst and a curing retarder to the mixture from the step (4).

The fifteenth aspect of the present invention is the method for producing the thermosetting silicone sponge rubber composition according to the fourteenth aspect, wherein the polyolganosiloxane in the step (1) is a mixture of methylvinylpolyolganosiloxane and hydroxylsiloxane .

A sixteenth aspect of the present invention relates to a sponge rubber product produced by curing the thermosetting silicone rubber composition of any one of the first to thirteenth aspects.

Since the thermosetting silicone sponge rubber composition of the present invention does not generate harmful decomposition products therefrom when the sponge is produced and can provide a silicone sponge rubber having uniform closed cells free from heat discoloration after curing, It is very advantageous to solve the problem of generation of harmful decomposition products and the problem of discoloration due to heat, which is a problem of the silicone sponge rubber.

The construction of the present invention will be described in more detail as follows.

It is preferred that the polyorganosiloxane silicon used in the preparation of the thermosetting silicone sponge rubber composition of the present invention has a degree of polymerization of from 5,000 to 10,000, a molecular weight of 400,000 to 700,000 and a viscosity at 25 ° C of 10,000,000 to 50,000,000 cPs. If the degree of polymerization, the molecular weight or the viscosity is abnormally high, the dispersion of the silica is difficult. If the degree of polymerization, the molecular weight or the viscosity is abnormally low, the processing easiness is lowered. Also, the polyorganosiloxane silicone has a repeating unit of the following formula: R _a SiO _{(4-a) / 2} wherein R is a hydroxyl group, an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms or an aliphatic unsaturated hydrocarbon group, 30 < / RTI > unsaturated hydrocarbon group; a has a value of 1.90 to 2.05. Specific examples thereof include dimethyl silicone gum, methylphenyl vinyl silicone gum, methylvinyl silicone gum, hydroxyl dimethyl silicone gum and fluorine silicone gum, and most preferably a mixture of methylvinyl silicone gum and hydroxyl dimethyl silicone gum do. Preferably, it is used in an amount of 20 to 50 parts by weight based on 100 parts by weight of hydroxydimethylsilicon black methyl vinyl silicone gum. When the amount of the hydroxyl dimethyl silicone gum is less than 20 parts by weight, the crosslinking speed is accelerated and it is difficult to foam. When the amount is more than 50 parts by weight, the crosslinking speed is slow and hard to be hardened.

The reinforcing silica used as a filler in the preparation of the thermosetting silicone sponge rubber composition of the present invention has a specific surface area of 150 m ² / g or more, preferably 180 to 240 m ² / g, an average particle size of 9 to 14 μm Size and a specific gravity of 1.9 to 2.2 g / cm < 3 >. If the average particle size or the specific gravity is too low, the processability is deteriorated due to floating in the reactor, and if the average particle size or specific gravity is too large, the mechanical strength is deteriorated. Such reinforcing silica is used in an amount of preferably 10 to 100 parts by weight, more preferably 20 to 60 parts by weight, based on 100 parts by weight of the polyorganosiloxane silicone gum. When the amount of the reinforcing silica is less than 10 parts by weight, the overall physical properties tend to deteriorate. When the amount of the reinforcing silica is more than 100 parts by weight, the dispersibility of the silica becomes poor and the mechanical properties may deteriorate. The lower the amount of silica and the higher the water content, the better the foaming performance of the product, but the workability is lowered, and it is difficult to obtain a uniform and fine cell.

The silicone-based processing aid having a functional group at the end used in the production of the thermosetting silicone sponge rubber composition of the present invention plays a role of improving the dispersibility of the filler, preventing creep hardening, improving flowability, and controlling plasticity. Preferably, a low viscosity polyorganosiloxane polymer having at least one functional group selected from the group consisting of a hydroxyl group, an alkoxy group and an amine group at the end and having a degree of polymerization of 2 to 60 may be used as the processing aid. Herein, the term "low viscosity" means a viscosity at 25 ° C. of preferably 100 cPs or less. The processing aid having a polymerization degree of 60 or 100 cPs or more has a deteriorated mechanical strength, which is not preferable.

In the present invention, the low viscosity polyorganosiloxane polymer may have a structure represented by the following formula (1).

Formula 1

In Formula 1,

R ¹ , R ² , R ³ and R ⁴ are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a vinyl group and a phenyl group;

Y is O, NH or NR ⁶ , wherein R ⁶ is an alkyl group having 1 to 10 carbon atoms;

R ⁵ is hydrogen or an alkyl group having 1 to 10 carbon atoms;

and n is an integer of 1 to 25. [

Examples of the low viscosity polyorganosiloxane polymer include dimethyl silicone having a hydroxy group at both terminals, a methylvinyl silicone polymer, a dimethyl silicone polymer having an alkoxy group at both terminals, and a dimethyl silicone polymer having an amino group at both terminals.

In the present invention, the silicon-based processing aid is used in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the polyorganosiloxane silicone gum. When the amount of the processing aid is less than 0.5 part by weight, dispersion of the reinforcing silica as a filler becomes difficult. When the amount exceeds 20 parts by weight, stickiness is caused in the composition, and workability in the roll mill is lowered.

In the production of the thermosetting silicone sponge rubber composition of the present invention, the polyorganohydrogensiloxane having both end groups or hard-chain groups at both ends used as a curing agent and a foaming agent, At the same time, it plays a role of controlling the foaming performance by using moisture generated by the dehydration reaction.

In the present invention, the polyorganohydrogensiloxane polymer may have a structure represented by the following formula (2).

(2)

In Formula 2,

R, R ¹ and R ² independently of one another are an aliphatic saturated hydrocarbon, an aliphatic unsaturated hydrocarbon, or an aromatic hydrocarbon, preferably a methyl, ethyl, butyl or aryl group;

m and n are each independently an integer of 10 to 100;

The polyorganohydrogensiloxane polymer preferably has a viscosity of 10 to 1,000 cPs at 25 DEG C, and preferably has a hydrogen content of 1.0 to 10 mmol / g. If the viscosity is too low, the reactivity increases and gelation phenomenon can occur. If the viscosity is too high, the reactivity becomes poor and the curing is delayed or the foaming performance is deteriorated.

In the present invention, the silicone polymer is used in an amount of preferably 1 to 20 parts by weight based on 100 parts by weight of the polyorganosiloxane silicone gum. If the amount of the silicone-based polymer is less than 1 part by weight, foaming can not be carried out. If the amount of the silicone-based polymer is more than 20 parts by weight, the curing rate is slowed and a non-uniform sponge shape is obtained.

The filler used as a stabilizer in the preparation of the thermosetting silicone sponge rubber composition of the present invention has a true specific gravity of 0.1 to 1.0 g / cc and a particle size of 500 mu m or less and has an average particle size of 150 to 200 mu m Glass bubble silica is preferred. If the average particle size is too low, the processability is poor. If the average particle size is too large, the bubble silica may be destroyed during the kneading process. This filler is a glassy component having 95% or more of soda lime borosilicate, and is used in an amount of preferably 1 to 20 parts by weight based on 100 parts by weight of the polyorganosiloxane silicone gum. If the amount of the filler used is less than 1 part by weight, the structure of the cell varies irregularly according to the working conditions. If the amount exceeds 20 parts by weight, the dispersion of the filler becomes poor and the roll workability becomes poor, and it is difficult to obtain a product with a smooth surface.

The platinum compound used as a catalyst in the production of the thermosetting silicone sponge rubber composition of the present invention crosslinks a polyorganosiloxane containing a vinyl group with a polyorganohydrogen siloxane. The platinum compound is preferably a complex compound with a low molecular weight vinylsiloxane in order to increase the reactivity and compatibility with the silicone polymer. The platinum content in the platinum compound added as a catalyst is 0.5 to 15%, and the platinum compound is used in an amount of 0.01 to 1.0 part by weight, preferably 0.1 to 0.5 part by weight based on 100 parts by weight of the polyorganosiloxane silicone rubber. When the amount of the catalyst is less than 0.01 part by weight, curing is not carried out. When the amount of the catalyst is more than 1.0 part by weight, curing proceeds too early at room temperature.

In the production of the thermosetting silicone sponge rubber composition of the present invention, the curing retarder is used for the purpose of stably controlling the curing rate by lowering the reactivity of the platinum compound used as the catalyst. The curing retarding agent is a compound having a double bond or a triple bond containing an alkenyl group, such as 1-ethynyl-1-cyclohexanol, 1,1,3,3-tetramethyl-1,3-divinyldisilazane , 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 2-methyl-3-butyne-2-ol, and phosphite-based retarders. The amount of the curing retarder to be used is preferably 0.05 to 0.5 parts by weight in the total rubber composition. If the amount of the curing agent is less than 0.05 parts by weight, the curing rate becomes excessively high. If the amount is more than 0.5 parts by weight, the silicone sponge rubber is not cured.

According to another aspect of the present invention, there is provided a method for producing a polyorganosiloxane, comprising: (1) pre-mixing polyorganosiloxane silicone gums into a kneader; (2) introducing into the kneader a reinforcing silica having a specific surface area of 150 m ² / g or more as a filler and a silicone-based processing aid having a functional group at the terminal; (3) stirring and dispersing the mixture from the step (2); And (4) further adding a silicon-based processing aid having a functional group at the end to the kneader and stirring the mixture at an elevated temperature to disperse it.

In step (1), polyorganosiloxane silicon gum is put into a kneader and pre-mixed, and the temperature inside the kneader is raised to 60 ° C or more simultaneously with the pre-mixing step.

According to another aspect of the present invention, there is provided a method for producing a polyorganosiloxane, comprising: (1) pre-mixing polyorganosiloxane silicon gums into a kneader; (2) introducing into the kneader a reinforcing silica having a specific surface area of 150 m ² / g or more as a filler and a silicone-based processing aid having a functional group at the terminal; (3) stirring and dispersing the mixture from the step (2); (4) adding a silicon-based processing aid having a functional group at its end to the kneader and stirring the mixture at an elevated temperature; And 5) adding to the mixture from step (4) a polyorganohydrogen siloxane, a stabilizer, a platinum catalyst and a curing retarder.

In the step (3), it is preferable that the mixture from the step (2) is dispersed by stirring at 110 to 140 ° C for 1 to 3 hours.

In the step (4), a silicon-based processing aid having a functional group at the end is further added to the kneader and dispersed by stirring at 150 to 180 ° C for 1 to 3 hours. The additional amount of the silicon-based processing aid in the step (4) is preferably 10 to 30% by weight of the total amount of the silicon-based processing aid and the amount added in the step (2).

The present invention will be described more specifically by the following examples and comparative examples, but the present invention is not limited thereto.

Example  One

According to the composition shown in the following Table 1, 80 parts by weight of methyl vinyl silicone blend (vinyl content in the syrup: 0.04 mol%, molecular weight: 400,000 to 500,000; viscosity at 25 DEG C: 10,000,000 to 30,000,000 cPs) and 20 parts by weight (BET value) as a filler was added to a kneader which was filled with a kneading agent (the molecular weight: 400,000 to 500,000; the viscosity at 25 DEG C: 10,000,000 to 30,000,000 cPs) having a hydroxyl group at its terminal end and a methyl group at its side chain, 40 parts by weight of wet silica (trade name: TOKUYAMA Tokusil-USA) having an average particle size of 12 m and a surface tension of 200 m < ² > / g, and 2.6 parts by weight of a dimethyl silicone polymer having a degree of polymerization of 5 to 15, Circuit division was added. 0.07 part by weight of calcium stearate, which is a conventional stabilizer for silicone rubber, was added. The mixture was stirred at 60 to 120 ° C for 20 minutes or more at each time of the addition, and the mixture was heated to 150 ° C to 170 ° C for 2 hours or more after cooling to 100 ° C. ) Were added thereto, and the mixture was stirred for 20 minutes and then taken out.

0.014 parts by weight of a platinum complex (ShinEtsu, PT-VTSC-1.0PS) per 100 parts by weight of silicone gum and 100 parts by weight of a phosphite type retarder (SONGNOX 1680 PX) And 5.5 parts by weight of a hydrogen polymer having an Si-H group of 7.3 mmol / g based on 100 parts by weight of the silicone gum. In order to inject, the polyorganosiloxane raw material taken out was divided into liquid type, and a platinum complex and a curing retardant were mixed using a roll miller on one side and a hydrogen polymer on the other side. The specific gravity of the final two obtained polyorganosiloxane raw materials was measured and plasticity was measured for 5 minutes after plasticizing for 5 minutes in a roll mill. The specific gravity before heating was 1.1 and the plasticity was measured as 180. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 DEG C for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured by a Shore C type hardness meter was 25 degrees and the specific gravity was measured to be 0.35. There was no yellowing or other discoloration, the surface was smooth, and had uniform, closed cells. The expansion ratio calculated by the formula [specific gravity before curing / specific gravity after curing = expansion ratio] was measured to be 3.14.

Comparative Example  One

According to the composition shown in the following Table 1, a kneader filled with 100 parts by weight of methyl vinyl silicone blade (vinyl content in the syrup: 0.04 mol%; molecular weight: 400,000 to 500,000; viscosity at 25 ° C: 10,000,000 to 30,000,000 cPs) And the same additives as the process of Example 1 were added to obtain two uncured compounds. The specific gravity of the two resulting polyorganosiloxane raw materials was measured and plasticity was measured for 5 minutes after plasticizing for 5 minutes in a roll mill. The specific gravity before heating was 1.1 and the plasticity was measured as 180. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 캜 for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured with a Shore C type hardness meter was 60 degrees and the specific gravity was measured to be 0.80. There was no yellowing or other discoloration, and the surface had a smooth, uniform, closed cell. The expansion ratio was measured to be 1.37.

Comparative Example  2

(Vinyl content in the syrup: 0.04 mol%, molecular weight: 400,000 to 500,000; viscosity at 25 DEG C: 10,000,000 to 30,000,000 cPs) and 50 parts by weight of a hydroxyl silicone rubber (The molecular weight: 400,000 to 500,000; the viscosity at 25 DEG C: 10,000,000 to 30,000,000 cPs) having a hydroxyl group at its terminal end and a methyl group at its side chain and being blocked with a methyl group, and the same filler and processing After the raw materials for preparation were added, the same processes and the same additives as in Example 1 were added to obtain two uncured compounds. The specific gravity of the two resulting polyorganosiloxane raw materials was measured and plasticity was measured for 5 minutes after plasticizing for 5 minutes in a roll mill. The specific gravity before heating was 1.1 and the plasticity was measured as 180. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 캜 for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured with a Shore C type hardness meter was 10 degrees and the specific gravity was measured to be 0.20. There was no yellowing or other discoloration but the surface was irregular and had irregular cells. The expansion ratio was measured at 5.50. The sponge was slightly uncured.

Comparative Example  3

According to the composition shown in the following Table 1, 80 parts by weight of a methylvinyl silicone blade and 20 parts by weight of a hydroxyl silicone blade were dry blended with a dry (dry) powder having a specific surface area (BET value) of 200 m ² / g and an average particle size of 12 μm 44 to 45 parts by weight of silica (trade name: TOKUYAMA CP-102), and the same processing aid and stabilizer as in Example 1 were charged, and then the same processes and the same additives as in Example 1 were added to prepare two uncured compounds . The specific gravity of the final two obtained polyorganosiloxane raw materials was measured and plasticity was measured for 5 minutes after plasticizing for 5 minutes in a roll mill. The specific gravity before heating was 1.2 and the plasticity was measured as 250. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 DEG C for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured with a Shore C type hardness tester was 55 degrees and the specific gravity was measured to be 0.85. There was no yellowing or other discoloration, the surface was smooth and had a uniform, closed cell. The expansion ratio was measured to be 1.29.

Example  2

According to the composition shown in the following Table 1, a kneader filled with 80 parts by weight of methyl vinyl silicone blade and 20 parts by weight of a hydroxyl silicone rubber had a specific surface area (BET value) of 200 m ² / g and an average particle size of 12 탆 20 parts by weight of wet silica (trade name: TOKUYAMA Tokusil-USA), 20 parts by weight of dry silica (trade name: TOKUYAMA CP-102) having a specific surface area (BET value) of 200 m ² / g and an average particle size of 12 μm, After the same processing aid and stabilizer as in Example 1 were added, the same processes and the same additives as in Example 1 were added to obtain two uncured compounds. The specific gravity of the final two obtained polyorganosiloxane raw materials was measured and plasticity was measured for 5 minutes after plasticizing for 5 minutes in a roll mill. The specific gravity before heating was 1.1 and the plasticity was measured as 220. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 DEG C for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured by a Shore C type hardness meter was 43 degrees and the specific gravity was measured to be 0.55. There was no yellowing or other discoloration, the surface was smooth and had a uniform, closed cell. The expansion ratio was measured as 2.0.

Comparative Example  4

According to the composition shown in the following Table 2, in the same manner as in Example 1, 50 parts by weight of methylvinyl silicone blade and 50 parts by weight of hydroxyl silicone rubber were charged into a kneader, After performing the same process, 3.5 parts by weight of Glass Bubble (VS-5500) was added, stirred for 20 minutes and then taken out.

0.014 parts by weight of a platinum complex (ShinEtsu, PT-VTSC-1.0PS), 0.007 part by weight of a phosphite-based retarder (Songwon Industrial Co., SONGNOX 1680 PX) and 100 parts by weight of a polyorganosiloxane raw material And 0.5 parts by weight of a hydrogen polymer having an Si-H group of 7.3 mmol / g. In the same manner as in Example 1, the specific gravity of the two polyorganosiloxane raw materials finally obtained after obtaining two uncured compounds was determined, plasticized for 5 minutes in a twin roll mill, and then measured for plasticity for 5 minutes Respectively. The specific gravity before heating was 1.13 and the plasticity was measured as 200. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 DEG C for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured by a Shore C type hardness meter was 60 degrees and the specific gravity was measured to be 1.16. There was no yellowing or other discoloration, the surface was rough, and the foaming rate could not be measured because it was not foamed.

Comparative Example  5

According to the composition shown in the following Table 2, in the same manner as in Example 1, 50 parts by weight of methylvinyl silicone blade and 50 parts by weight of hydroxyl silicone rubber were charged into a kneader, After performing the same process, a glass bubble (VS-5500) was added, stirred for 20 minutes, and then taken out.

0.014 parts by weight of a platinum complex (ShinEtsu, PT-VTSC-1.0PS), 0.007 part by weight of a phosphite-based retarder (Songwon Industrial Co., SONGNOX 1680 PX) and 100 parts by weight of a polyorganosiloxane raw material And 20 parts by weight of a hydrogen polymer having an Si-H group of 7.3 mmol / g. In the same manner as in Example 1, the specific gravity of the two polyorganosiloxane raw materials finally obtained after obtaining two uncured compounds was determined, plasticized for 5 minutes in a twin roll mill, and then measured for plasticity for 5 minutes Respectively. The specific gravity before curing was 1.07 and the plasticity was measured as 150. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 DEG C for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured by a Shore C type hardness meter was 60 degrees and the specific gravity was measured to be 0.22. There was no yellowing or other discoloration, and the surface was smooth but had nonuniform closed cells. The foaming ratio was measured to be 4.86. It was slightly uncured.

Comparative Example  6

According to the composition shown in the following Table 2, in the same manner as in Example 1, 50 parts by weight of methylvinyl silicone blade and 50 parts by weight of hydroxyl silicone rubber were charged into a kneader, After the same process was performed, the mixture was stirred for 20 minutes in the state that no glass bubble (VS-5500) was added, and then taken out.

The specific gravity of the two polyorganosiloxane raw materials ultimately obtained by adding the platinum complex, the phosphite retarder and the hydrogen polymer to the raw polyorganosiloxane raw material thus obtained was measured in the same manner as in Example 1, After plasticizing for 5 minutes, plasticity was measured for 5 minutes. The specific gravity before curing was 1.16 and the plasticity was measured as 180. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 DEG C for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured by a Shore C type hardness meter was 30 degrees and the specific gravity was measured to be 0.35. There was no yellowing or other discoloration, but the surface was rugged and had unequal closed cells. The foaming ratio was measured to be 3.31.

Comparative Example  7

According to the composition shown in the following Table 2, a raw material such as a filler and a processing aid was added to a kneader filled with 50 parts by weight of a methylvinyl silicone blade and 50 parts by weight of a hydroxyl silicone blade in the same manner as in Example 1, , 10 parts by weight of glass bubble (VS-5500) was added, stirred for 20 minutes, and then taken out.

The specific gravity of the two polyorganosiloxane raw materials ultimately obtained by adding the platinum complex, the phosphite retarder and the hydrogen polymer to the raw polyorganosiloxane raw material thus obtained was measured in the same manner as in Example 1, After plasticizing for 5 minutes, plasticity was measured for 5 minutes. In Touroyl Miller, the uncured compounds were severely cracked and poorly worked. The specific gravity before curing was 1.03 and the plasticity was measured as 240. The mixed polyorganosiloxane raw material was cut into a sheet having a thickness of 3 mm and then cured at 230 캜 for 5 minutes to prepare a silicone rubber sponge sheet. The hardness of the sheet measured by a Shore C type hardness meter was 23 degrees and the specific gravity was measured to be 0.33. There was no yellowing or other discoloration, and the surface was smooth and had a uniform, closed cell. The foaming ratio was measured to be 3.12.

As can be seen from the results of Tables 1 and 2, when Examples 1 and 5 and Comparative Examples 2, 3, 4 and 6-9 are compared, Examples 1 and 5 show the roll workability, yellowing state, The uniformity of the cell, the expansion ratio of the cell, and the like.

According to the present invention, a polyorganosiloxane silicone gum containing vinyl group and a silicone gum containing a hydroxyl group are mixed together, and then reinforcing silica, silicone-based processing aid, and stabilizer are added. Thereafter, when the polyorganosiloxane containing a vinyl group and the polyorganohydrogensiloxane containing a hydrogen group at both ends or side chains are cured by an addition reaction under a platinum catalyst, water produced by the dehydration reaction is used, It is very advantageous in that it is possible to provide a silicone rubber composition capable of forming a uniform and closed cell without discoloration and a method of manufacturing the same.

Claims (16)

(a) 100 parts by weight of a mixture of methyl vinyl polyorganosiloxane gum and hydroxyl polyorganosiloxane gum;
Based on 100 parts by weight of component (a)
(b) 10 to 100 parts by weight of a reinforcing silica having a specific surface area of 150 m ² / g or more as a filler;
(c) 0.5 to 20 parts by weight of a silicone-based processing aid having a terminal functional group;
(d) 1 to 10 parts by weight of a polyorganohydrogensiloxane containing a hardening group at its terminal or side chain;
(e) 1 to 10 parts by weight of a stabilizer containing not less than 95% by weight of soda lime borosilicate;
(f) 0.001 to 1 part by weight of a platinum catalyst; And
(g) hardening retardant 0.001 to 0.5 parts by weight
Lt; / RTI >
Wherein the silicone-based processing aid is a polyorganosiloxane polymer having a viscosity of 100 cPs or less at 25 캜 and a structure represented by the following formula (1):
Formula 1

In Formula 1,
R ¹ , R ² , R ³ and R ⁴ are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a vinyl group and a phenyl group;
Y is O, NH or NR ⁶ , wherein R ⁶ is an alkyl group having 1 to 10 carbon atoms;
R ⁵ is hydrogen or an alkyl group having 1 to 10 carbon atoms;
and n is an integer of 1 to 25. [ The method according to claim 1,
Wherein said methyl vinyl polyorganosiloxane gum or hydroxyl polyorganosiloxane gum has a viscosity at 25 DEG C of 10,000,000 cPs or more and has a repeating unit of the formula R _a SiO _{(4-a) / 2} , wherein R is a hydroxyl group, An aliphatic saturated hydrocarbon group or aliphatic unsaturated hydrocarbon group of 1 to 10 carbon atoms or an aromatic unsaturated hydrocarbon group of 6 to 30 carbon atoms, and a has a value of 1.90 to 2.05. The method according to claim 1,
Wherein the reinforcing silica is a wet silica having an average particle size of 9.5 to 1412 占 퐉 and a specific gravity of 1.9 to 2.2 g / cm3. delete The method according to claim 1,
Wherein the polyorganohydrogensiloxane has a structure represented by the following formula (2): < EMI ID =
(2)

In Formula 2,
R, R ¹ and R ² are, independently of each other, an aliphatic saturated hydrocarbon, aliphatic unsaturated hydrocarbon, or aromatic hydrocarbon;
m and n are each independently an integer of 10 to 100; 6. The method of claim 5,
Wherein R, R ¹ and R ² are independently selected from the group consisting of methyl, ethyl, butyl and aryl groups. The method according to claim 1,
Wherein the stabilizer has a true specific gravity of 0.1 to 1.0 g / cc and a particle size of 500 mu m or less. 8. The method of claim 7,
Wherein the stabilizer has an average particle size of from 150 to 200 mu m. The method according to claim 1,
Wherein the platinum catalyst forms a complex with the vinyl siloxane, wherein the oxidation number is 0 and the platinum content is 0.5 to 15 wt%. The method according to claim 1,
Wherein the content of the platinum catalyst is 0.1 to 0.5 parts by weight. The method according to claim 1,
Wherein the hardening retarder has a double bond or triple bond containing an alkenyl group. The method according to claim 1,
Wherein the curing retardant is selected from the group consisting of 1-ethynyl-1-cyclohexanol, 1,1,3,3-tetramethyl-1,3-divinyldisilazane, 2,4,6,8- 4,6,8-tetravinylcyclotetrasiloxane, 2-methyl-3-butyne-2-ol, and a phosphite-based retarder. The method according to claim 1,
And the content of the curing retarder is 0.1 to 0.5 parts by weight. (1) pre-mixing a polyorganosiloxane silicone gum into a kneader;
(2) introducing into the kneader a reinforcing silica having a specific surface area of 150 m ² / g or more as a filler and a silicone-based processing aid having a functional group at the terminal;
(3) stirring and dispersing the mixture from the step (2);
(4) adding a silicon-based processing aid having a functional group at its end to the kneader and stirring the mixture at an elevated temperature;
(5) adding to the mixture from the step (4) a polyorganohydrogen siloxane containing hard halogen groups at both ends or side chain, a stabilizer containing 95 wt% or more of soda lime borosilicate, a platinum catalyst, Adding a retarding agent
Lt; / RTI >
10 to 100 parts by weight of reinforcing silica relative to 100 parts by weight of polyorganosiloxane silicone gum; 0.5 to 20 parts by weight of a silicone-based processing aid; 1 to 10 parts by weight of a polyorganohydrogensiloxane containing a hardening group at the terminal or side chain; 1 to 10 parts by weight of a stabilizer containing not less than 95% by weight of soda lime borosilicate; 0.001 to 1 part by weight of a platinum catalyst; And 0.001 to 0.5 parts by weight of a hardening retarder,
Wherein the silicone-based processing aid is a polyorganosiloxane polymer having a viscosity at 25 DEG C of not more than 100 cPs and having a structure represented by the following formula (1): < EMI ID =
Formula 1

In Formula 1,
R ¹ , R ² , R ³ and R ⁴ are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a vinyl group and a phenyl group;
Y is O, NH or NR ⁶ , wherein R ⁶ is an alkyl group having 1 to 10 carbon atoms;
R ⁵ is hydrogen or an alkyl group having 1 to 10 carbon atoms;
and n is an integer of 1 to 25. [
A method of manufacturing a thermosetting silicone sponge rubber composition. 15. The method of claim 14,
Wherein the polyolganosiloxane in the step (1) is a mixture of methylvinylpolyolganosiloxane and hydroxylsiloxane. A sponge rubber product produced by curing the thermosetting silicone sponge rubber composition of any one of claims 1 to 3 and 5 to 13.