TW201444918A - Foamable silicone rubber composition and silicone rubber sponge - Google Patents

Abstract

The present invention provides a foamable silicone rubber composition of silicone rubber sponge capable of reducing the generation of odor during the use of foaming agents such as AIBN, and a silicone rubber sponge formed by curing the composition. The foamable silicone rubber composition of the present invention comprises the following components: (A) 100 parts by mass of organopolysiloxane expressed by the average compositional formula (1) R1aSiO(4-a)/2 (R1 represents the same or different substituted or non-substituted univalent hydrocarbon group; and a is a positive number of 1.95-2.04), each molecule of organopolysiloxane having at least two alkenyl groups with no less than 100 degree of polymerization; (B) 3 to 100 parts by mass of reinforcing silica having a specific surface area 50 m<SP>2</SP>/g or more; (C) 0.1 to 100 parts by mass of cellulose derivative powder; and (D) an effective amount of hardening agent for curing the component (A).

Description

Foaming polyoxymethylene rubber composition and polyoxyethylene rubber sponge

The present invention relates to a foamable polyoxymethylene rubber which can be used for a building foam, a sponge sheet, an industrial roller, a photocopier, a sponge roller for a business machine, a heat insulating sheet, and the like. And a polyoxyxene rubber foam (polyoxyethylene rubber sponge) obtained by foaming and curing the composition.

Polyoxyethylene rubber sponge (ie, polyoxymethylene rubber foam) has physical properties peculiar to polyoxyxene rubber and is excellent in heat resistance, cold resistance, electrical insulation, flame retardancy, and compression set. nature. The polyoxyethylene rubber sponge is basically a combination of a thermosetting polyoxyxene rubber composition, a curing agent and a foaming agent, which is foamed and hardened by heating to form a sponge, and the focus is excellent in foamability ( That is, a foam having a high expansion ratio and a low density is provided, and has a uniform and fine cell structure without impairing the physical properties peculiar to the polyoxymethylene rubber.

Most of the processing methods are hardened and foamed in a continuously formed hot air. In order to obtain a polyoxyethylene rubber sponge, azobisisobutyronitrile (AIBN), dimethyl 1,1'-azobis(1-cyclohexanecarboxylate) is usually used. An organic azo-based foaming agent such as an acid ester, but a component produced by decomposition of such a foaming agent may cause an odor.

In JP-A-2002-146078 (Patent Document 1), it is proposed that a non-cyanide-based organic azo compound can be used to obtain a foaming agent having high safety even if it is not post-hardened for a long period of time, but there is no such thing as a safety agent. A method of reducing the odor generated is described.

[Practical Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-146078

In view of the above circumstances, the present invention provides a foamable polyoxyxene rubber composition which is obtained by using a polyoxyethylene rubber sponge which is reduced in odor generated when a foaming agent is used by using AIBN or the like. The composition is a foamed and hardened polyoxyethylene rubber sponge.

In order to achieve the above object, the present inventors have intensively studied the results of the review and found that the use of a cellulose derivative as a foaming agent can reduce the odor generated during heating and foaming, and the present invention has been completed.

Therefore, the present invention provides the following expandable polyoxyxene rubber composition and a polyoxyxene rubber sponge obtained by foaming and curing the composition.

[1] A foamable polyoxyxene rubber composition containing

(A) 100 parts by mass of an organopolysiloxane having a polymerization degree of at least 2 alkenyl groups of 100 or more in one molecule, represented by the following average composition formula (I)

R ¹ _a SiO _(4-a)/2 (I) (wherein R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05)

(B) Reinforcing cerium oxide having a specific surface area of 50 m ² /g or more and 3 to 100 parts by mass

(C) Cellulose derivative powder 0.1 to 100 parts by mass

(D) Hardener An effective amount to harden the component (A).

[2] The foamable polyoxyxene rubber composition according to [1], wherein the cellulose derivative powder of the component (C) is water-insoluble.

[3] The foamable polyoxyxene rubber composition according to [2], wherein the cellulose derivative powder system of the component (C) has a water content of 0.1 to 50% by mass.

[4] The foamable polyoxyxene rubber composition according to [1], wherein the cellulose derivative powder system of the component (C) is selected from the group consisting of methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl fiber. A powder of at least one of a phenol, a hydroxypropylcellulose, and a carboxymethylcellulose.

[5] The foamable polyoxyxene rubber composition according to [1], which further contains 0.01 to 10 parts by mass of water as the component (E) per 100 parts by mass of the component (A).

[6] The foamable polyoxyxene rubber composition according to [5], wherein the cellulose derivative powder system of the component (C) has previously absorbed the water of the component (E).

[7] The foamable polyoxyxene rubber composition according to [1], wherein the hardener is an addition reaction type hardener or an organic peroxide.

[8] The foamable polyoxymethylene rubber composition as described in [7], wherein the addition is The reactive hardener is an organic hydrogen polyoxyalkylene having at least two hydrogen atoms bonded to a ruthenium atom in one molecule in an amount of 0.1 to 30 parts by mass based on 100 parts by mass of the component (A). In the component (A), a platinum group metal catalyst having a platinum-based metal mass of 1 ppm to 1% by mass is used.

[9] A polyoxyxene rubber sponge obtained by foaming and curing the foamable polyoxyxene rubber composition according to any one of [1] to [8].

[10] The polyoxyethylene rubber sponge according to [9], wherein the sponge density is less than 1.0 g/cm ³ .

In the present invention, since a foaming agent such as AIBN is not used, a foamable polyoxyxene rubber composition capable of producing a polyoxyxene rubber sponge which is less odor generated during foam curing is provided and A polyoxyethylene rubber sponge in which the composition is foamed and hardened.

[In order to implement the invention] - (A) ingredients -

In the present invention, the component (A) is an organopolysiloxane having at least two alkenyl groups bonded to a ruthenium atom in one molecule, represented by the following average composition formula (I).

R ¹ _a SiO _(4-a)/2 (I) (wherein R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05).

In the above average composition formula (I), R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and usually has a carbon number of 1 to 12, particularly preferably a carbon number of 1 to 8, particularly For example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group or an octyl group; a cycloalkyl group such as a cyclopentyl group or a cyclohexyl group; an alkenyl group such as a vinyl group, an allyl group or a propenyl group; An aryl group such as a phenyl group or a tolyl group; an aralkyl group such as a benzyl group or a 2-phenylethyl group; or a halogen atom of a part or all of such a group is a halogen atom, a chlorine atom or a bromine atom. The substituted group such as an atom or a cyano group is preferably a methyl group, a vinyl group, a phenyl group or a trifluoropropyl group, and more preferably a methyl group or a vinyl group.

Specifically, the repeating structure of the diorganosiloxane unit (the R ¹ ₂ SiO _2/2 and the R ¹ system are the same as the above, and the same applies hereinafter) constituting the main chain of the organopolysiloxane is only a dimethyl methoxide having a repeating unit of dimethyl methoxy oxane or a part of a dimethyl methoxy oxane unit constituting the main chain is structured to have a phenyl group, a vinyl group, and 3, 3,3-trifluoropropyl or the like as a substituent of diphenyloxane unit, methylphenyloxirane unit, methylvinyloxirane unit, methyl-3,3,3-trifluoro It is preferred to use a diorganosiloxane unit such as a propyloxane unit.

Further, both ends of the molecular chain are, for example, a trimethylphosphonium oxyalkyl group, a dimethylphenyl sulfoxyalkyl group, a vinyl dimethyl decyloxyalkyl group, a divinylmethyl decyloxy group, a trivinyl fluorene. a hydroxydiorganophosphonyloxy group such as an oxoalkyl group such as a triorganophosphorylalkyl group (R ¹ ₃ SiO _1/2 ) or a hydroxydimethylphosphonyloxy group (R ¹ ₂ (HO)SiO _{1/ 2} ) The other end is preferred. Among these, the reactivity of trivinylsulfonyloxy group is particularly preferable.

In particular, the organopolyoxyalkylene as the component (A) must have two or more alkenyl groups bonded to a halogen atom in one molecule. It is usually 2 to 50, particularly preferably having about 2 to 20 alkenyl groups, and more preferably having a vinyl group. In this case, 0.01 to 20 mol% (preferably 0.02 to 10 mol%) of all R ¹ is preferably an alkenyl group. Moreover, the alkenyl group may be bonded to a ruthenium atom at the end of the molecule, or may be bonded to a ruthenium atom on the way of the molecular chain (end of the non-molecular chain), or may be both, but at least bonded to the end of the molecular chain. Helium atoms are preferred.

In addition, a is 1.95 to 2.05, preferably 1.98 to 2.02, and more preferably a positive number of 1.99 to 2.01. Further, 90 mol% or more of all R ¹ is an alkyl group (preferably 95 mol% or more, and more preferably all of R ¹ except an alkenyl group is an alkyl group, particularly a methyl group).

The organopolyoxyalkylene can be obtained by, for example, hydrolyzing or condensing one or two or more kinds of organic halogen halogens, or using a basic or acidic catalyst to form a cyclic polyoxane (a siloxane). 3-mer, tetramer, etc.) are obtained by ring-opening polymerization. These are basically linear diorganopolyoxyalkylene oxides, and as the component (A), they may be a mixture of two or more different molecular weights (degrees of polymerization) or molecular structures.

Further, the degree of polymerization of the above organopolysiloxane is preferably 100 or more (usually 100 to 100,000), more preferably 2,000 to 50,000, and most preferably 3,000 to 20,000, at room temperature (25 ° C). It is preferably not self-flowing, that is, it is rubbery (non-liquid). When the degree of polymerization is too small, there is a fear that the roll may be caused by the composite, and the roll workability may be lowered. and Further, the degree of polymerization can usually be measured by a gel permeation chromatography (GPC) using toluene as a developing solvent to measure the weight average degree of polymerization in terms of standard polystyrene.

- (B) ingredients -

The reinforcing cerium oxide of the component (B) is added when a polythene oxide rubber composition having excellent mechanical strength is added, and in order to achieve the object, the specific surface area (BET adsorption method) must be 50 m ² /g or more. Preferably, it is 100 to 450 m ² /g, and more preferably 100 to 300 m ² /g. When the specific surface area is less than 50 m ² /g, the mechanical strength of the cured product may be lowered.

As the reinforcing cerium oxide, for example, an aerosol type cerium oxide (dry cerium oxide or smoky cerium oxide), a precipitated cerium oxide (wet cerium oxide), or the like, or such a surface is chlorodecane It is preferred that the hexamethyldioxane or the like is hydrophobized. Among them, smoke-type cerium oxide having excellent dynamic fatigue characteristics is preferred. The component (B) may be used alone or in combination of two or more.

As the reinforcing cerium oxide of the component (B), commercially available products such as Aerosil 130, Aerosil 200, Aerosil 300, Aerosil R-812, Aerosil R-972, Aerosil R-974, etc., Aerosil series (Japan Aerosil (Japanese Aerosil (Japanese)) can be used. Co., Ltd.), Cabosil MS-5, MS-7 (manufactured by CABOT), Rosil QS-102, 103, MT-10 (manufactured by TOKUYAMA Co., Ltd.), etc., whose surface is untreated or surface-hydrophobized (ie, hydrophilic) Sexual or hydrophobic) aerosolized cerium oxide, or surface treated with Tokusil US-F (manufactured by TOKUYAMA Co., Ltd.), NIPSIL-SS, NIPSIL-LP (manufactured by SILICA Co., Ltd.), etc., or surface-hydrophobized Precipitated cerium oxide and the like.

The blending amount of the reinforcing cerium oxide of the component (B) is 3 to 100 parts by mass, preferably 5 to 100 parts by mass, per 100 parts by mass of the organopolysiloxane of the component (A). More preferably, it is 20 to 80 parts by mass, and the most preferred is 50 to 80 parts by mass. When the blending amount of the component (B) is too small, the reinforcing effect cannot be obtained. When the amount is too large, the workability is deteriorated and the mechanical strength is lowered.

-(C) ingredients -

a cellulose derivative powder of the component (C) (particularly a hydroxyl group in part or all of the cellulose skeleton, which is selected from the group consisting of alkyl, ethyl, propyl, etc., alkyl, hydroxymethyl, hydroxyethyl, hydroxypropyl An ionic or nonionic cellulose ether substituted with one or two or more kinds of substituents such as a hydroxyalkyl group such as a hydroxyalkyl group, a carboxymethyl group or a carboxyethyl group, etc., at room temperature (25 °C) is a solid fine powder, and a component added when foaming the polyoxyxene rubber is particularly preferably water-insoluble (that is, nonionic), and 0.1 to 100 is added to the component (A). The mass fraction is preferably from 1 to 20 parts by mass, more preferably from 2 to 15 parts by mass, and is dispersed. When the amount of the cellulose derivative powder is less than 0.1 part by mass, a sufficient foaming effect may not be obtained; when it exceeds 100 parts by mass, the workability of the polyoxymethylene rubber composition is deteriorated or the rubber strength is also lowered and it is not economical. Therefore, it is not for the sake of seeking.

The cellulose derivative powder particles of the present invention have an average particle diameter of from 1 to 150 μm, preferably from 1 to 50 μm, more preferably from 3 to 20 μm, and most preferably from 5 to 16 μm. When the average particle diameter is smaller than 1 μm, the mixing efficiency of the fine particles may be lowered. When the average particle diameter is larger than 150 μm, the problem that the rubber properties of the large particles are lowered may occur.

Moreover, in the present invention, the measurement of the average particle diameter can be obtained by using a thunder The cumulative weight average D50 (or medium diameter) of the particle size distribution measurement by the diffracting of the light.

As the cellulose derivative powder, a commercially available product can be used. For example, a carboxyalkyl-substituted ionic cellulose ether such as carboxymethylcellulose (CELLOGEN) manufactured by Daiichi Kogyo Co., Ltd., or a hydroxyethyl group manufactured by Diacel can be used. Cellulose (HEC), methyl cellulose manufactured by Shin-Etsu Chemical Co., Ltd., hydroxypropylmethylcellulose (METOLOSE 90SH-100,000), hydroxypropylcellulose (L-HPC, LODICEL LDC-H), etc. An alkyl group and/or a hydroxyalkyl group-substituted nonionic cellulose ether or the like.

At this time, since the commercially available cellulose derivative powder contains water, the moisture in the cellulose derivative powder is related to foaming. In this regard, the water content recommended as the cellulose derivative powder is usually from 0.1 to 50% by mass, preferably from 0.5 to 30% by mass, more preferably from 0.5 to 15% by mass.

-(D) ingredients -

The curing agent (D) is not particularly limited as long as it can cure the component (A), and is generally a (i) addition reaction (hydrazine hydrogenation reaction) as a rubber curing agent. A type hardener, that is, a combination of an organic hydrogen polyoxyalkylene (crosslinking agent) and a rhodium hydrogenation catalyst, and (ii) an organic peroxide are preferred.

The organic hydrogen polyoxyalkylene as the crosslinking agent of the addition reaction (hydrogenation reaction) has at least two hydrogen atoms (SiH groups) bonded to a ruthenium atom in one molecule, and the following applies. The conventional organic hydrogen polyoxyalkylene represented by the formula (II) is averaged.

R ² _b H _c SiO _{(4-bc) / 2} (II) (wherein R ² represents the same or different unsubstituted or substituted monovalent hydrocarbon group, b is 0.7 to 2.1, and c is 0.01 to 1.0 And b+c is a positive number from 0.8 to 3.0).

Here, R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, preferably those having no aliphatic unsaturated bond. Specifically, there are an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group or a hexyl group; a cycloalkyl group such as a cyclohexyl group; a phenyl group; At least one of the hydrogen atoms of the above-mentioned monovalent hydrocarbon group such as an unsubstituted monovalent hydrocarbon group such as an aryl group or a benzyl group or the like, an aralkyl group such as a benzyl group, or the like, a 3,3,3-trifluoropropyl group or a cyanomethyl group. A substituted monovalent hydrocarbon group such as a substituted alkyl group substituted with a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom or a cyano group. b is 0.7~2.1, c is 0.01~1.0, and b+c is 0.8~3.0, preferably b is 0.8~2.0, c is 0.10~1.0, better is 0.18~1.0, and the best is 0.2~ 1.0, and satisfies b+c as a positive number of 1.0~2.5.

Further, the molecular structure of the organohydrogenpolyoxane may be any one of a linear, a cyclic, a branched, and a ternary mesh. In this case, the number of germanium atoms (or the degree of polymerization) in one molecule is from 2 to 300, and particularly preferably from about 4 to about 200, it is preferably liquid at room temperature (25 ° C). Further, the hydrogen atom (SiH group) bonded to the ruthenium atom may be at the end of the molecular chain, or may be in the side chain (middle of the molecular chain), or both, and has at least 2 (usually 2) in one molecule. ~300), preferably more than 3 (for example, 3 to 200), and more preferably 4 to 150.

The organohydrogen polyoxyalkylene, such as 1,1,3,3-tetramethyldioxane, 1,3,5,7-tetramethylcyclotetraoxane, methylhydrocyclopolyoxyalkylene , methylhydroquinone oxime dimethyl dimethyl oxane cyclic copolymer, ginseng (dimethylhydroquinoloxy) methyl decane, ginseng (dimethylhydroquinoloxy) phenyl decane, two end three Methyl decyloxy-terminated methylhydrogenpolyoxyalkylene, two-terminal trimethyldecaneoxy-terminated dimethyl methoxy oxane hydrazine methylhydroquinoxane copolymer, two-terminal dimethylhydroquinoloxy Blocked dimethyl polyoxane, two-terminal dimethylhydroquinoloxy-terminated dimethyl methoxy oxane hydrazine methylhydroquinone copolymer, two-terminal trimethyl decyloxy-terminated methyl hydrogen矽 烷 ̇ ̇ 矽 矽 矽 矽 共聚物 共聚物 、 、 、 共聚物 共聚物 共聚物 ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ ̇ 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物 共聚物Hydrogen polyoxyalkylene, cyclic methylhydroquinone oxime dimethyl dimethyl siloxane copolymer, cyclic methylhydroquinone oxime diphenyl fluorene oxime dimethyl hydrazine copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit copolymer formed by (CH ₃ ) a copolymer of ₂ HSiO _1/2 unit and SiO _4/2 unit and (C ₆ H ₅ )SiO _3/2 unit, or a part or all of a methyl group in each of the above-exemplified compounds is ethyl or propyl. Other aryl group substituents such as an alkyl group or a phenyl group. Further, specific examples of the organic hydrogen polyoxyalkylene are compounds of the following structural formula.

(where k is an integer from 2 to 10, and s and t are each an integer from 0 to 10).

The organic hydrogen polyoxyalkylene has a viscosity at 25 ° C of 0.5 to 10,000 mPa ̇ s, particularly preferably 1 to 300 mPa ̇ s. Viscosity can be measured by a rotary viscometer.

Further, the organohydrogenpolyoxyalkylene is bonded to the ruthenium atom in an organic hydrogen polysiloxane by blending an aliphatic unsaturated group bonded to an alkenyl group such as a ruthenium atom in the component (A). The molar ratio (SiH group/aliphatic unsaturation) of the hydrogen atom (i.e., SiH group) is 0.5 to 10 m/mole, preferably 0.8 to 6 m/m, and more preferably 1 ~5 mole / mole amount is appropriate. When it is less than 0.5 mol/mole, the crosslinking action becomes insufficient, and sufficient mechanical strength cannot be obtained. Further, when it exceeds 10 mol/mole, physical properties after hardening are lowered, particularly heat resistance and The case where the compression set resistance is remarkably deteriorated.

The amount of organic hydrogen polyoxyalkylene blended is such that the organic group of component (A) is polymerized. The effective amount of the oxane curing is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the organopolysiloxane of the component (A). 0.3 to 10 parts by mass.

Further, the ruthenium hydrogenation catalyst used in the crosslinking reaction of the above (i) addition reaction (hydrazine hydrogenation reaction) is an aliphatic unsaturated group (for example, an alkenyl group) in the component (A). A catalyst for the addition reaction of a hydrogen atom (SiH group) bonded to a halogen atom in the above-mentioned organic hydrogen polysulfoxane of the crosslinking agent. The rhodium hydrogenation catalyst may, for example, be a platinum group metal catalyst, a platinum group metal monomer and a compound thereof, and a conventional one may be used as a catalyst for an addition reaction hardening type polyoxo rubber composition. For example, a particulate platinum metal adsorbed on a carrier such as cerium oxide, alumina or cerium oxide gel, platinum chloride, chloroplatinic acid, chloroplatinic acid 6 aqueous salt alcohol solution, palladium contact may be exemplified. The catalyst or the catalyst is preferably a platinum or platinum compound.

The amount of the ruthenium hydrogenation catalyst to be added may be such that the amount of the catalyst can be promoted, that is, the amount of the platinum group metal in the range of 1 ppm to 1% by mass in the amount of the component (A). A range of 500 ppm is preferred. When the amount of addition is less than 1 ppm, the addition reaction may not be sufficiently promoted, and the curing may be insufficient. Further, when the amount is more than 1% by mass, even if the amount is added, the influence on the reactivity is small, and it is not economically effective. .

Further, in addition to the above-mentioned catalyst, in order to adjust the curing rate, an addition-crosslinking controlling agent may be used. Specifically, for example, ethynylcyclohexanol or tetramethyltetravinylcyclotetraoxane can be mentioned.

Further, as the (ii) organic peroxide, for example, benzammonium peroxide, 2,4-dibenzylbenzhydryl peroxide, p-methylbenzhydryl peroxide can be exemplified. Base, peroxy o-methylbenzhydryl, 2,4-dicumenyl peroxide, 2,5-dimethyl-bis(2,5-t-butylperoxy)hexane, di- T-butyl peroxide, t-butyl perbenzoate, 1,6-hexanediol-bis-t-butyl peroxycarboxylate, and the like.

The amount of the organic peroxide added is 0.1 to 15 parts by mass, particularly preferably 0.2 to 10 parts by mass, per 100 parts by mass of the component (A). When the amount of addition is too small, the crosslinking reaction may not be sufficiently performed, and the physical properties such as a decrease in hardness, an insufficient rubber strength, and an increase in compression set may be deteriorated. When the amount is too large, not only the economic benefits are poor, but most of them produce a hardener. Decomposition, deterioration of physical properties such as increase in compression set, or increase in discoloration of the obtained sheet.

-(E) ingredients -

The component (E) is water, and any component can be blended as needed. By adding water, the expansion ratio of the sponge can be increased. Water may be added arbitrarily, and the amount of water added is 0.01 to 10 parts by mass, particularly 0.1 to 5, based on 100 parts by mass of the alkenyl group-containing organic polysiloxane of the component (A). The mass portion is preferred.

The water of the component (E) may be added simultaneously with the components (A) to (D), and in particular, a considerable amount of water may be absorbed in the cellulose derivative of the component (C) in advance. The preliminary absorption operation of (E) water in the (C) cellulose derivative component can be carried out by externally adding water while stirring the cellulose derivative, or by using an environment under high humidity conditions (usually The cellulose derivative is placed at a specified time for 50% RH or more, particularly 75% RH or more in air or in a nitrogen gas atmosphere, and a specified amount of water is absorbed. At this time, When the amount of water absorbed in the cellulose derivative particles is too small, the expansion ratio is lowered, and when it is too large, the cells as the sponge become large, and at the same time, the processability of the composite is deteriorated, the water content is determined by the cellulose derivative particles. It is preferably from about 0.1 to 50% by mass, particularly preferably from about 0.5 to 30% by mass, more preferably from about 0.5 to 15% by mass.

-Other ingredients -

Further, in the present invention, a conductive sponge can be formed by adding a conductive material. The type and amount of the conductive material are not particularly limited, and conductive carbon black or conductive metal oxide particles such as conductive zinc white or conductive titanium oxide can be used, and the conductive material can be used alone. It is also possible to use two or more types together.

The carbon black may be generally used in a conductive rubber composition, such as acetylene black, conductive furnace black (CF), superconducting furnace black (SCF), elastic conductive furnace black (XCF), and conductive groove black. (CC), furnace black or channel black which is heat-treated at a high temperature of about 1500 to 3000 °C. For example, DENKABLACK (manufactured by DENKI KAGAKU Co., Ltd.), SHAWINIGAN ACETYLENE BLACK (manufactured by SHAWINIGAN CHEMICAL Co., Ltd.), etc., and conductive furnace black, such as CONTINEX CF (manufactured by CONTINENTAL CARBON Co., Ltd.) and VULCAN C (manufactured by CABOT Co., Ltd.) ), superconducting furnace black such as CONTINEX SCF (manufactured by CONTINENTAL CARBON Co., Ltd.), VULCAN SC (manufactured by CABOT Co., Ltd.), etc.; elastic conductive furnace black such as ASAHI HS-500 (made by ASAHI CARBON), VULCAN XC-72 (CABOT) Company system), etc.; conductive groove black such as CALLUX L (DEGUSSA company In addition, a kitchen black KITCHEN BLACK EC300JD and KITCHEN BLACK EC-600JD (Kitchen Black International Co., Ltd.) and the like of one of the furnace blacks can be used. The furnace black preferably has a sulfur element concentration of 6000 ppm or less (preferably 3000 ppm or less) in terms of impurities, particularly sulfur or sulfur compounds. Further, among these, KITCHEN EC300JD or KITCHEN EC-600JD which has excellent conductivity even at a low filling amount can be preferably used in terms of its significantly large specific surface area.

The amount of the conductive carbon black to be added is preferably 1 to 30 parts by mass, particularly preferably 5 to 20 parts by mass, per 100 parts by mass of the component (A). When the amount is less than 1 part by mass, the desired conductivity cannot be obtained. When the amount is more than 30 parts by mass, the rubber hardenability may be lowered, and the intended rubber elasticity may not be obtained.

In addition, conductive metal oxide fine particles, for example, conductive zinc white, titanium oxide, tin-based fine particles, and the like, specifically, conductive zinc oxide such as zinc oxide 23-K (trade name) manufactured by Hakusui Tech Co., Ltd., Or a conductive white zinc FX (trade name) manufactured by HONJO CHEMICAL Co., Ltd.; and a white conductive titanium oxide such as ET-500W (trade name, manufactured by Ishihara Sangyo Co., Ltd.). By adding 1 to 300 parts by mass of such a single type of fine particles or using carbon black in combination, the intended resistance can be obtained.

In the polyoxyethylene rubber sponge composition of the present invention (foaming polyoxyxene rubber composition), pulverized quartz, zinc oxide, aluminum oxide (alumina) as a thermal conductivity imparting material may be further added as needed. Or a non-reinforcing cerium oxide, a filler such as calcium carbonate, a coloring agent, a heat resistance improving agent, a flame retardant improving agent, an acid receiving agent, a heat conduction improving agent, or the like. A dispersing agent such as an additive or a releasing agent, an alkoxy decane, a diphenyl decane diol, a carbon functional decane, a terminal sterol alcohol group-terminated low molecular siloxane, or the like.

The method for producing the foamable polyoxyxene rubber composition of the present invention is not particularly limited, and it can be obtained by kneading a predetermined amount of the above components by two rolls, a kneader, a Banbury mixer or the like.

The prepared polyoxyethylene rubber sponge composition can be easily obtained by heat-expanding and foaming to obtain a polyoxyethylene rubber sponge. The hardening foaming method may be a method in which the foaming agent is decomposed and sufficient heat is applied to the vulcanization reaction of the polyoxyxene rubber, and the forming method may be continuously vulcanized, pressed, and borrowed by extrusion molding. The molding by inkjet molding or the like is not particularly limited, and in particular, it is preferred to use atmospheric pressure hot gas vulcanization in the present invention. In this case, the heating temperature is 100 to 500 ° C, particularly 150 to 400 ° C, and the time is several seconds to 1 hour, particularly 10 seconds to 30 minutes, preferably. In addition, depending on the requirements, the vulcanization may be carried out twice at about 180 to 250 ° C for about 1 to 10 hours.

Further, the polyoxyethylene rubber sponge (polyoxymethylene rubber foam) obtained by foaming the composition of the present invention is a sponge having a high expansion ratio, and the sponge density at 25 ° C can be easily made up to 1.0 g/cm. ³ (usually 0.1 to 0.9 g/cm ³ ), preferably about 0.2 to 0.8 g/cm ³ , more preferably about 0.3 to 0.7 g/cm ³ of a low density polyoxyethylene rubber sponge.

In the following, the examples and comparative examples are shown, specifically It is to be understood that the invention is not limited to the embodiments described below. Further, in the following examples, the parts represent parts by mass. Moreover, room temperature means 25 ° C.

[Examples] [Example 1]

The blending machine is formed by dimethyl methoxyoxane unit 99.825 mol%, methyl vinyl fluorene oxide unit 0.15 mol%, dimethyl vinyl fluorene oxide unit 0.025 mol%, average polymerization degree 100 parts of dry cerium oxide Arosil 200 (manufactured by Arosil Co., Ltd.) having an organic polyoxyalkylene content of about 8,000 and a BET specific surface area of 200 m ² /g, having a stanol group at both ends and having a viscosity of 29 mPa ̇s ( 5 parts of dimethylpolyoxane at 25 ° C and heat-treated at 180 ° C for 2 hours to prepare a matrix rubber composite.

METHOS 90SH-100,000 (trade name of Shin-Etsu Chemical Co., Ltd.; hydroxypropylmethylcellulose) having a water content of 4.5% by mass as a cellulose derivative was added and added as an addition hardening by two rolls. 0.5 parts of C-25A (platinum catalyst) and 2.0 parts of C-25B (organohydrogen polyoxyalkylene) (all manufactured by Shin-Etsu Chemical Co., Ltd.) were used to prepare a rubber composite sheet having a thickness of 5 mm.

Then, the sheet having a thickness of 5 mm was subjected to atmospheric hot air vulcanization for 15 minutes in a hot air dryer at 230 ° C to obtain a polyoxyethylene rubber sponge. The sponge was taken out from the dryer to observe the degree of odor. The sponge density was measured after removing the surface layer from the obtained sponge. The evaluation results are shown in Tables 1-2.

Odor level [test methods]

The formed sheet was subjected to atmospheric hot air vulcanization (HAV) by a hot air dryer, and after cooling at room temperature for about 30 minutes, the taste of the foamed sheet was evaluated by smell. (Evaluation is based on the maximum number of participants in the assessment).

[evaluation method]

0: Very little smell

1: slightly smelly

2: moderate odor

3: Slightly strong smell

4: Strong smell

5: The smell is quite strong

Sponge density determination method

After removing the surface layer (surface layer) from the obtained sponge, the sponge density (g/cm ³ ) at room temperature (25 ° C) was measured by a water substitution method.

[Embodiment 2]

Except for the use of LODICEL LDC-H (trade name of Shin-Etsu Chemical Co., Ltd.; hydroxypropylcellulose) having a water content of 9.8% by mass, 10 parts of METOLOS 90SH-100,000 as a cellulose derivative, 1 In the same manner, a polyoxyethylene rubber sponge was formed and the same evaluation was performed.

[Example 3]

The molding was carried out in the same manner as in Example 1 except that 0.05 part of water was added as the component (E).

[Example 4]

The molding was carried out in the same manner as in Example 1 except that 0.1 part of water was added as the component (E).

[Example 5]

The water-absorbing LODICEL LDC-H (trade name of Shin-Etsu Chemical Co., Ltd.) was used to replace METOLOS 90SH-100,000. After the LODICEL LDC-H absorbs moisture in a constant temperature and humidity chamber having a humidity of 85% RH, it is added to the polyoxyethylene rubber. The water content is 10.5% by mass of the cellulose derivative particles.

Then, a polyoxyethylene rubber sponge was formed by the same method as in Example 1.

[Embodiment 6]

A polyoxyethylene rubber sponge was formed by the same method as in Example 1 except that the cellulose derivative METOLOS 90 SH-10 was added in an amount of 15 parts.

[Comparative Example 1]

In addition to using 1.5 parts of azoisobutyronitrile (AIBN) to replace cellulose derivatives Further, a polyoxyethylene rubber sponge was formed by the same method as in Example 1, and the same evaluation was performed.

[Comparative Example 2]

A polyoxyethylene rubber sponge was formed by the same method as in Example 1, except that 1.5 parts of dimethyl 1,1'-azobis(1-cyclohexanecarboxylate) was used instead of the cellulose derivative, and Make the same assessment.

[Comparative Example 3]

A polyoxyethylene rubber sponge was formed by the same method as in Example 1 except that the cellulose derivative was not added, and the same evaluation was performed.

Claims (10)

A foamable polyoxyxene rubber composition comprising (A) an organopolyoxyalkylene having a degree of polymerization of at least two alkenyl groups having a degree of polymerization of at least two alkenyl groups in one molecule represented by the following average composition formula (I) 100 parts by mass of R ¹ _a SiO _(4-a)/2 (I) (wherein R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05) (B) 3 to 100 parts by mass of the reinforcing cerium oxide having a specific surface area of 50 m ² /g or more (C) 0.1 to 100 parts by mass of the cellulose derivative powder (D) an effective amount of the curing agent (A). The foamable polyoxyxene rubber composition according to claim 1, wherein the cellulose derivative powder of the component (C) is water-insoluble. The foamable polyoxyxene rubber composition according to claim 2, wherein the cellulose derivative powder system of the component (C) has a water content of 0.1 to 50% by mass. The foaming polyoxyxene rubber composition according to claim 1, wherein the cellulose derivative powder system of the component (C) is selected from the group consisting of methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl cellulose. A powder of at least one of hydroxypropylcellulose and carboxymethylcellulose. Such as the composition of the foaming polyoxyxene rubber of claim 1 The material further contains 0.01 to 10 parts by mass of water as the component (E) with respect to 100 parts by mass of the component (A). The foamable polyoxyxene rubber composition according to claim 5, wherein the cellulose derivative powder system of the component (C) has previously absorbed the water of the component (E). The foamable polyoxyxene rubber composition according to claim 1, wherein the hardener is an addition reaction type hardener or an organic peroxide. The foaming polyoxyxene rubber composition according to the seventh aspect of the invention, wherein the addition-reactive hardener is 0.1 to 30 parts by mass based on 100 parts by mass of the component (A). An organohydrogen polyoxyalkylene having at least two hydrogen atoms bonded to a ruthenium atom and a platinum group metal catalyst having a platinum-based metal mass ratio of 1 ppm to 1% by mass based on the component (A) . A polyoxyxene rubber sponge obtained by foaming and hardening an expandable polyoxyxene rubber composition according to any one of claims 1 to 8. For example, the polyoxyethylene rubber sponge of claim 9 wherein the sponge density is less than 1.0 g/cm ³ .