JP2006063096A - Silicone rubber pattern-taking material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicone rubber pattern-taking material, markedly improving a mold-releasing performance of duplicated articles from a mold (a silicone rubber mold) after curing by suppressing the residual nitrogen content which is an organosilazane residue present in a fine amount in the pattern-taking material so as to be able to improve the pattern-taking durability of the silicone rubber mold against a urethane resin or an epoxy resin. <P>SOLUTION: This silicone rubber pattern-taking material consists of a composition containing (A) an organopolysiloxane having ≥2 monovalent aliphatic unsaturated hydrocarbon groups bonded with silicon atom in one molecule, (B) an organohydrogenpolysiloxane having ≥2 hydrogen atoms bonded with silicon atom in one molecule, (C) a platinum-based compound and (D) an inorganic filler, and has ≤25 ppm residual amount of the nitrogen in the composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an addition reaction type silicone rubber molding material. More specifically, the present invention is used for molding which requires a high degree of releasability, such as molding of a prototype model, that is, prototype molding, by curing into a rubber shape. The present invention relates to a silicone rubber molding material that provides a silicone rubber matrix that is excellent in mold releasability of molded products such as urethane resins and epoxy resins, and has a significantly improved number of moldings.

  In the present invention, the mold material is fluid in an uncured state, and is brought into contact with the entire surface or a part of the original surface by a method such as casting or coating, and is cured in that state. This refers to an uncured (liquid) material that forms a mold (mould for mold making) to be replicated with a resin or the like. Further, in the present invention, the releasability is a term including not only the releasability from the original mold of the hardened mold (matrix) but also the releasability of the replicated product from the obtained mold (matrix). Use.

  Conventionally, silicone rubber has been widely used in various fields by taking advantage of its excellent heat resistance, cold resistance, electrical characteristics, etc. Especially, since it has good releasability, it is used as a silicone rubber mold (matrix). Has been used. Molding materials using silicone rubber composition improve cost and required time in prototype molding used in the product development stage and product sample preparation in the fields of electronic equipment, office machines, home appliances, automobile parts, etc. In view of workability, an addition reaction type liquid silicone rubber composition has been frequently used.

  The addition reaction type silicone rubber composition has preferable molding characteristics as a molding material. However, as the mechanical properties of the urethane resin and epoxy resin used in the molding of the prototype are improved, the silicone rubber composition is improved from the silicone rubber mold (matrix). There is a tendency for mold release to become worse.

  In order to solve such problems, approaches have been made from both aspects of a base polymer, a crosslinking agent and a catalyst system involved in an addition reaction of a molding material (silicone rubber composition), and a compounding agent. As the former, for example, as disclosed in Japanese Patent Application Laid-Open No. 58-19357 (Patent Document 1), a method of blending a crosslinking agent from which low molecular polyorganohydrogensiloxane is removed is exemplified, and as the latter, JP, 58-225152, A (patent documents 2) WHEREIN: The method of mix | blending a non-reactive silicone oil is illustrated. However, the former alone does not provide sufficient results for the high demands imposed on the present invention, and the latter does not provide sufficient silicone oil for cross-linking. The strength is likely to be reduced, and the duplicated product is soiled because the oil oozes out. Japanese Patent Application Laid-Open No. 50-66533 (Patent Document 3) discloses that the releasability is improved by blending a non-reactive silicone oil and titanium oxide in a condensation reaction type liquid silicone rubber composition. However, in this case, there is a problem that the type and amount of other fillers used in combination are limited.

  Conventionally, a silica filler is used for the above molding material, and in this case, silica having an active surface can be used by surface-treating the silica filler with various organosilazane compounds. (For example, Japanese Patent Publication No. 58-8703, US Pat. No. 4,152,315, US Pat. No. 4,427,801 (Japanese Patent Publication No. 63-46786), etc.) ~ 6).

  Japanese Patent Laid-Open No. 2-70755 (Patent Document 7) is obtained when silica subjected to surface treatment again with hexamethyldisilazane is used as a filler of a polyorganosiloxane composition that is cured by an addition reaction. It is disclosed that the obtained silicone rubber mold is excellent in mechanical strength and excellent in mold release durability.

JP 58-19357 A JP 58-225152 A JP 50-66533 A Japanese Patent Publication No.58-8703 US Pat. No. 4,152,315 US Pat. No. 4,427,801 (Japanese Patent Publication No. 63-46786) Japanese Patent Laid-Open No. 2-70755

  The present invention has been made in view of the above circumstances, and when producing a replica using a high-performance urethane resin or epoxy resin, it excels in mechanical strength and releasability of the replica, and increases the number of molds taken. An object of the present invention is to provide a silicone rubber molding material capable of forming a silicone rubber mold (matrix) suitable for molding which requires a high degree of releasability, such as a prototype.

  As a result of intensive studies to achieve the above object, the present inventors have a poor cause of the above-mentioned releasability, and a major cause of a significant decrease in the number of molds and workability is an inorganic filler such as silica. In addition to finding the organosilazane residue remaining when the surface is treated with organosilazane, and suppressing the residual nitrogen content of the organosilazane residue present in trace amounts in this silicone rubber molding material, When replicas are manufactured using the urethane resin or epoxy resin, the release performance of the replica from the mold after curing (silicone rubber matrix) is significantly improved. In particular, the present inventors have found that it can be a silicone rubber molding material suitable for molding that requires a high degree of releasability, such as a prototype.

That is, the present invention
(A) 100 parts by mass of an organopolysiloxane having two or more monovalent aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule;
(B) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom in one molecule (A) Bonded to a silicon atom for one monovalent aliphatic unsaturated hydrocarbon group in the component An amount such that the number of hydrogen atoms is 0.5 to 5;
(C) Platinum-based compound (A) It consists of a composition containing 0.1 to 1,000 ppm in terms of platinum atom mass with respect to component; and (D) 5 to 100 parts by mass of an inorganic filler. A silicone rubber molding material having a residual nitrogen content of 25 ppm or less is provided.

  In this case, as the inorganic filler, those treated with an organosilazane are effectively used. In order to reduce the organosilazane residue as much as possible to reduce the residual nitrogen amount to 25 ppm or less, the above (A It is effective to add organosilazanes to the component (D) for surface treatment of the component (D) and to mix and stir the mixture at a temperature of 160 ° C. or higher for 3 hours or more.

  The silicone rubber mold material of the present invention suppresses the residual nitrogen content, which is an organosilazane residue present in a small amount in the mold material, thereby separating the duplicated product from the mold after curing (silicone rubber matrix). The mold performance is remarkably improved, and the mold-molding durability of the silicone rubber matrix for urethane resin and epoxy resin can be improved.

The silicone rubber mold molding material of the present invention is composed of a composition containing the following components (A) to (D), and the amount of residual nitrogen in the composition is 25 ppm or less.
(A) an organopolysiloxane having two or more monovalent aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule;
(B) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule;
(C) platinum compound,
(D) Inorganic filler

  The organopolysiloxane of component (A) used in the present invention is a component that becomes the base polymer of the above composition. This component (A) has 2 or more, preferably 2 to 50, more preferably 2 to 20 monovalent aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule. Any structure may be used as long as it can form a network structure (crosslinked structure) by the chemical addition reaction.

  Examples of the monovalent aliphatic unsaturated hydrocarbon group include alkenyl groups having about 2 to 6 carbon atoms such as vinyl group, allyl group, propenyl group, 1-butenyl group, and 1-hexenyl group, but are easily synthesized. In view of not impairing the fluidity of the composition before curing and the heat resistance of the composition after curing, a vinyl group is most advantageous.

  Other monovalent organic groups bonded to the silicon atom of component (A) include methyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, pentyl, hexyl, and cyclohexyl. Group, octyl group, decyl group, alkyl group such as dodecyl group; aryl group such as phenyl group; aralkyl group such as benzyl group, 2-phenylethyl group, 2-phenylpropyl group; chloromethyl group, chlorophenyl group, 2- Usually, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably about 1 to 8 carbon atoms, such as a substituted hydrocarbon group such as a cyanoethyl group and a 3,3,3-trifluoropropyl group is exemplified. The Of these, a methyl group and a phenyl group are most preferred because they are easily synthesized and have a good balance of properties such as mechanical strength and fluidity before curing.

  The monovalent aliphatic unsaturated hydrocarbon group may be present at either the end of the molecular chain or in the middle of the molecular chain of the organopolysiloxane, or may be present in both of them. In order to provide a specific property, in the case of a straight chain, it is preferably present at least at both ends.

The siloxane skeleton may be linear, branched or three-dimensional network, but in the case of linear, the main chain is composed of repeating diorganosiloxane units and both ends of the molecular chain. Is preferably a diorganopolysiloxane blocked with a triorganosiloxy group. In order to improve the mechanical properties of the composition after curing and to use it for molding of complex shapes such as prototypes, linear diorganopolysiloxane and branched or three-dimensional network organopolysiloxane are usually used. It is preferable to use a mixture, but when used for casting an epoxy resin, particularly a transparent epoxy resin that requires smoothness of the surface, if a branched or three-dimensional network organopolysiloxane is present, its resinification For this reason, the hardness of the silicone rubber mold is increased or the smoothness is impaired. In such a case, it is preferable to use only a linear diorganopolysiloxane. In the case of using a mixture of a linear diorganopolysiloxane and a branched or three-dimensional network organopolysiloxane as described above, in order to increase the mechanical strength and elastic modulus of the cured product, R ₃ SiO _{1 / 2} units and SiO ₂ units and optionally R ₂ SiO units (R represents the above-mentioned monovalent organic group, and at least two, preferably three or more in one molecule of R are monovalent aliphatic unsaturated groups. A linear diorganopolysiloxane containing 2 to 40% by mass of a three-dimensional network organopolysiloxane composed of a hydrocarbon group), the remainder being blocked with monovalent aliphatic unsaturated hydrocarbon groups at both ends. It is preferable to use a mixture of

  The degree of polymerization of the component (A) is such that the composition before curing has good fluidity and workability, and the composition after curing has an appropriate elasticity at 25 ° C. measured by a rotational viscometer or the like. Those having a viscosity of 500 to 500,000 mPa · s are preferred, and those having a viscosity of 1,000 to 100,000 mPa · s are particularly preferred.

  The organohydrogenpolysiloxane of the component (B) used in the present invention is a monovalent aliphatic unsaturated hydrocarbon group in which the hydrosilyl group (Si-H group) contained in the molecule is 2 or more. It functions as a crosslinking agent for the component (A) by performing an addition reaction to the hydrogen atom (Si-H) bonded to the silicon atom involved in the addition reaction in order to crosslink and cure the composition. Group) at least 2 (usually 2 to 200), preferably 3 or more, and particularly about 3 to 100.

  Examples of the monovalent organic group other than the hydrogen atom bonded to the silicon atom of the siloxane unit include those similar to the monovalent organic group other than the monovalent aliphatic unsaturated hydrocarbon group in the component (A) described above, Among these, a methyl group and a phenyl group are most preferable from the viewpoint of easy synthesis.

  The siloxane skeleton in the component (B) may be linear, branched, three-dimensional network structure or cyclic. Moreover, although a mixture of these may be used, a linear thing is more preferable.

  The degree of polymerization of component (B) (or the number of silicon atoms in one molecule) is not particularly limited, but organohydrogenpolysiloxanes in which two or more hydrogen atoms are bonded to the same silicon atom are difficult to synthesize. It is preferably composed of 2 or more, especially 3 to 200, especially 4 to 100 siloxane units, and is easy to handle and does not volatilize during storage and when heated for a curing reaction. More preferably, the viscosity at 25 ° C. measured by 1 is 1 to 500 mPa · s, particularly 15 to 200 mPa · s.

  The blending amount of the component (B) is such that a hydrogen atom (Si—H group) bonded to a silicon atom in the component (B) is one monovalent aliphatic unsaturated hydrocarbon group in the component (A). The amount is 0.5 to 5, preferably 1 to 3. When the amount of the silicon atom-bonded hydrogen atoms is less than 0.5, the curing is not completely completed. Therefore, the mold obtained by curing the composition is sticky, and the silicone rubber is transformed from the original mold. The mold releasability when the mold is molded, and the mold releasability of the replica obtained by molding with respect to the silicone rubber mold are lowered. On the contrary, if the abundance ratio exceeds 5 pieces, foaming is likely to occur during curing, and it is a replica product obtained by molding with the interface between the original mold and the silicone rubber mold and with the silicone rubber mold. Not only does it accumulate on the interface and gives molds and replicas with poor surface conditions, but also the resulting silicone rubber mold becomes brittle, leading to a decrease in the number of resin castings, that is, a decrease in mold taking life, Mechanical strength is reduced.

Specific examples of the (B) component organohydrogenpolysiloxane include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, and tris (hydrogendimethyl). Siloxy) methylsilane, tris (hydrogendimethylsiloxy) phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, trimethylsiloxy group-blocked methylhydrogenpolysiloxane, trimethylsiloxy group at both ends Blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends dimethylhydrogensiloxy group blocked dimethylpolysiloxane, both ends dimethylhydrogensiloxy group blocked dimethylsiloxane Methyl hydrogen siloxane copolymer, both ends trimethylsiloxy group blocked methyl hydrogen siloxane / diphenyl siloxane copolymer, both ends trimethyl siloxy group blocked methyl hydrogen siloxane / diphenyl siloxane / dimethyl siloxane copolymer, both ends trimethyl siloxy group Blocked methylhydrogensiloxane / methylphenylsiloxane / dimethylsiloxane copolymer, both ends dimethylhydrogensiloxy group blocked methylhydrogensiloxane / dimethylsiloxane / diphenylsiloxane copolymer, both ends dimethylhydrogensiloxy group blocked methylhydrogensiloxane・ Dimethylsiloxane ・ Methylphenylsiloxane copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and (CH ₃ ) ₃ SiO _1/2 unit And copolymers comprising SiO _4/2 units, (CH _{3) 2} HSiO _1/2 consisting of units and SiO _4/2 units, and copolymers thereof, (CH _{3) 2} HSiO _1/2 units and SiO _{4 /} Examples thereof include a copolymer comprising ₂ units and (C ₆ H ₅ ) ₃ SiO _1/2 units.

  The platinum compound of the component (C) used in the present invention is a catalyst for promoting the addition reaction between the monovalent aliphatic unsaturated hydrocarbon group in the component (A) and the hydrosilyl group in the component (B). It is excellent in that the catalytic ability of the curing reaction is good around room temperature.

  Examples of such platinum compounds include platinum black, chloroplatinic acid, complexes obtained by reacting chloroplatinic acid and alcohol, platinum-olefin complexes, platinum-vinylsiloxane complexes, platinum-ketone complexes, platinum-aldehyde complexes, etc. Is exemplified. Among these, a reaction product of chloroplatinic acid and an alcohol, a platinum-vinylsiloxane complex, and the like are preferable from the viewpoint of good solubility in the component (A) and the component (B) and catalytic activity.

  Component (C) is added in an amount of 0.1 to 1,000 ppm, preferably 1 to 100 ppm, more preferably 2 to 50 ppm in terms of platinum atom (mass) relative to component (A). If it is less than 0.1 ppm, the curing speed is slow and the curing is not completely completed. Therefore, the silicone rubber mold is sticky, and the releasability of the silicone rubber mold from the original mold and the replica of the silicone rubber mold. The releasability decreases. If it exceeds 1,000 ppm, the curing rate becomes excessively fast, so the workability after blending each component is impaired, and it is also uneconomical.

  The inorganic filler of component (D) in the present invention imparts mechanical properties to the cured product of the composition. Examples of such inorganic fillers include silica-based powders such as fumed silica, precipitated silica, fused silica, ground quartz (crystalline silica), and diatomaceous earth, and hexamethylene disilazane, octamethyltrisilazane, and divinyl. Using surface treatment agents such as tetramethyldisilazane, organosilazane such as dimethyltetravinyldisilazane, organoalkoxysilane, organohalogenosilane, linear or cyclic organopolysiloxane having a low polymerization degree, reflux system, suspension Hydrophobized by a method such as a method, an atmospheric fluidized bed method, or a pressure method; and powders such as calcium carbonate, aluminum silicate, titanium oxide, zinc oxide, iron oxide, and carbon black are exemplified. In order to obtain good mechanical properties, fumed silica is preferred, and fumed silica surface-treated with organosilazanes such as hexamethyldisilazane is more preferred.

Further, the inorganic filler used in the present invention preferably has a specific surface area by BET method is 50 to 400 m ² / g, in particular 100 to 250 m ² / g. If the specific surface area is less than 50 m ² / g, sufficient reinforcing properties may not be obtained, and if it exceeds 400 m ² / g, the viscosity of the composition may become very high and workability may be impaired.

  (D) The compounding quantity of a component gives a favorable mechanical characteristic to the silicone rubber type | mold obtained by hardening, Therefore It is 5-100 mass parts with respect to 100 mass parts of (A) component, and 10-50 mass parts Is preferred. When the amount is less than 5 parts by mass, sufficient reinforcing properties cannot be obtained, and when it exceeds 100 parts by mass, the viscosity of the composition becomes very high and workability is impaired.

  In the composition which can be the silicone rubber mold material of the present invention, other components can be blended depending on the purpose within a range not impairing the characteristics of the present invention. That is, in order to improve the workability by extending the curing time at room temperature of the silicone rubber mold material of the present invention, curing such as acetylene compound, diallyl maleate, triallyl isocyanurate, nitrile compound or organic peroxide A retarder may be blended. Furthermore, you may mix | blend a mold release agent, a pigment, a plasticizer, a flame retardance imparting agent, a thixotropy imparting agent, an antibacterial agent, an antifungal agent, etc. as needed.

  The silicone rubber mold molding material of the present invention is characterized in that the amount of residual nitrogen present in a small amount in the composition obtained above is 25 ppm or less (ie, 0 to 25 ppm) with respect to the total composition (mass), preferably It is limited to 0-23 ppm, more preferably 0-18 ppm. By using such a composition, adhesion with the casting resin is suppressed, and the number of times of molding the resin can be dramatically improved.

  In this case, the residual nitrogen is mainly based on the organosilazanes used for the surface treatment of the inorganic filler. Here, the surface treatment with the organosilazanes of the inorganic filler is preferably performed when the silicone rubber compound is produced by mixing the above-mentioned component (A) and the inorganic filler of the component (D). The method of adding an organosilazane to the component (D) and surface-treating the inorganic filler is good. In this case, in order to make the residual nitrogen in the silicone rubber molding material within the above range, the above ( A), a mixture of component (D) and organosilazane (silicone rubber compound) at 160 ° C. or higher (usually about 160 to 230 ° C.) for 3 hours or longer, particularly 180 to 220 ° C. for 3 to 6 hours, especially 190 to 200 It is preferable to perform the heat mixing treatment at 3 ° C. for 3 to 4 hours.

  And it is preferable to add and mix (B) and (C) component with the silicone rubber compound obtained in this way. In addition, optional components other than the components (A) to (D) and organosilazanes may be added at the time of producing the compound, or added to the obtained compound together with the components (B) and (C). May be. Usually, the component group containing the component (B) and the component group containing the component (C) are prepared separately and stored, and both components are mixed and used immediately before use. It is also possible to store all components in the same container in the presence of a retarder. Here, the mixing and kneading of the above components can be prepared by uniformly kneading using a known mixer such as a universal kneader, kneader, planetary mixer, Shinagawa mixer or the like.

  The amount of residual nitrogen in the silicone rubber molding material can be measured by a combustion method, for example, using a TN-02 model manufactured by Mitsubishi Kasei Co., Ltd. can do.

  When the silicone rubber molding material of the present invention is stored in a plurality of containers, these are uniformly mixed and defoamed, and when stored in a single container, it is extruded as it is to wrap the prototype, or the prototype A silicone rubber mold is produced by casting or applying to a part of the surface of the mold and curing it. Here, curing can be performed at room temperature to slight heating of about 60 ° C., but curing may be accelerated by heating up to 150 ° C. depending on conditions. After curing, the rubber mold is removed from the original mold, a molding resin such as urethane resin or epoxy resin is cast, cured at a curing temperature corresponding to each resin, and demolded to obtain a replica. .

  EXAMPLES Hereinafter, although a preparation example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following Example. In addition, in the following examples, a part represents a mass part and a viscosity shows the value in 25 degreeC measured with the Toki Sangyo Co., Ltd. rotational viscometer RB80H. The amount of residual nitrogen in the composition was measured with a TN analyzer TN-02 manufactured by Mitsubishi Kasei Co., Ltd.

-Preparation of silicone compound [Preparation Example 1-1]
(A) 100 parts of linear dimethylpolysiloxane having a viscosity of 10,000 mPa · s (vinyl group content = 0.0053 mol / 100 g) having both ends blocked with dimethylvinylsiloxy groups, fumed silica (BET method) (Specific surface area: 200 m ² / g, tap density: 0.2 g / ml), 40 parts of hexamethyldisilazane, and 2.5 parts of water were mixed in a kneader at room temperature for 1 hour. Next, the temperature inside the kneader was raised to 160 ° C. over 60 minutes, and the mixing was continued for 4 hours while maintaining the temperature to obtain a silicone compound (1). The residual nitrogen content of the obtained compound was measured and found to be 17 ppm.

[Preparation Example 1-2]
A silicone compound (2) was obtained in the same manner as in Preparation Example 1-1 except that the temperature inside the kneader was raised to 200 ° C. over 60 minutes and the mixing was continued for 4 hours while maintaining the temperature. The residual nitrogen content of the obtained compound was measured and found to be 13 ppm.

[Preparation Example 1-3]
A silicone compound (3) was obtained in the same manner as in Preparation Example 1-1 except that the temperature inside the kneader was raised to 200 ° C. over 60 minutes and mixing was continued for 3 hours while maintaining the temperature. The residual nitrogen content of the obtained compound was measured and found to be 24 ppm.

[Preparation Example 1-4 (for comparison)]
A silicone compound (4) was obtained in the same manner as in Preparation Example 1-1 except that the temperature inside the kneader was raised to 160 ° C. over 60 minutes and mixing was continued for 2 hours while maintaining the temperature. The residual nitrogen content of the obtained compound was measured and found to be 50 ppm.

[Preparation Example 1-5 (for comparison)]
A silicone compound (5) was obtained in the same manner as in Preparation Example 1-1 except that the temperature inside the kneader was raised to 200 ° C. over 60 minutes and mixing was continued for 1 hour while maintaining the temperature. The residual nitrogen content of the obtained compound was measured and found to be 45 ppm.

-Preparation of curing agent [Preparation Example 2]
(A) Molecular chain both ends dimethylvinylsiloxy group-blocked dimethylpolysiloxane having a viscosity of 10,000 mPa · s (vinyl group content = 0.0053 mol / 100 g) 100 parts, (B) Molecular chain both ends trimethyl having a viscosity of 30 mPa · s 3 parts of siloxy group-blocked methyl hydrogen polysiloxane (Si—H bond hydrogen atom content = 1.5 mass%), (C) thermoplastic silicone resin having a softening point of 80-90 ° C. with a complex of chloroplatinic acid and vinylsiloxane A curing agent (6) was prepared by uniformly mixing 0.3 part of the catalyst dispersed in fine particles (in this composition, the amount of platinum metal in the catalyst is 5 ppm). The amount of residual nitrogen in the obtained curing agent was measured and found to be 0 ppm.

[Example 1]
The silicone compound (1) and the curing agent (6) were mixed at a ratio of 100: 10 (mass ratio) by a planetary mixer to prepare a silicone rubber composition. The amount of residual nitrogen in the composition was 16 ppm. Next, the silicone rubber composition is heated in a heating oven at 60 ° C. for 4 hours to produce a cured silicone rubber mold (50 mm × 50 mm × 50 mm, shape: concave), and the following measurement method In accordance with the above, the number of times of endurance for mold taking with respect to the urethane resin was measured.

[Example 2]
The silicone compound (2) and the curing agent (6) were mixed at a ratio of 100: 10 (mass ratio) by a planetary mixer to prepare a silicone rubber composition. The amount of residual nitrogen in the composition was 12 ppm. Next, the silicone rubber composition is heated in a heating oven at 60 ° C. for 4 hours to produce a cured silicone rubber mold (50 mm × 50 mm × 50 mm, shape: concave), and the following measurement method In accordance with the above, the number of times of endurance for mold taking with respect to the urethane resin was measured.

[Example 3]
The silicone compound (3) and the curing agent (6) were mixed at a ratio of 100: 10 (mass ratio) by a planetary mixer to prepare a silicone rubber composition. The amount of residual nitrogen in the composition was 22 ppm. Next, the silicone rubber composition is heated in a heating oven at 60 ° C. for 4 hours to produce a cured silicone rubber mold (50 mm × 50 mm × 50 mm, shape: concave), and the following measurement method In accordance with the above, the number of times of endurance for mold taking with respect to the urethane resin was measured.

[Comparative Example 1]
Each measurement was performed in the same manner as in Example 1 except that the silicone compound (4) was used instead of the silicone compound (1). In addition, the residual nitrogen amount of the obtained composition was 45 ppm.

[Comparative Example 2]
Each measurement was performed in the same manner as in Example 1 except that the silicone compound (5) was used instead of the silicone compound (1). In addition, the residual nitrogen amount of the obtained composition was 41 ppm.

<Measurement method>
-Molding durability for urethane resin 1. Inject urethane resin into a silicone rubber mold (moulding mold).
2. Next, the injected urethane resin is cured at 70 ° C. for 30 minutes.
3. Next, the cured urethane resin is removed from the silicone rubber mold.
The above steps 1 to 3 were repeated, and the number of times until the silicone rubber mold could not be used due to adhesion between the urethane resin cured product and the silicone rubber mold was counted.
The measurement results in Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1.

[Evaluation]
As is clear from the above results, in Examples 1 to 3 using compositions in which the amount of residual nitrogen satisfies a predetermined condition (range of 25 ppm or less), the composition has excellent releasability. Improvement in mold-making durability with respect to the urethane resin of the mother mold obtained by curing and molding was observed.

  On the other hand, in Comparative Examples 1 and 2 using a composition in which the amount of residual nitrogen does not satisfy the predetermined condition, there is a slight problem with the mold release property. It was inferior to 1-3.

Claims (3)

(A) 100 parts by mass of an organopolysiloxane having two or more monovalent aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule;
(B) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom in one molecule (A) Bonded to a silicon atom for one monovalent aliphatic unsaturated hydrocarbon group in the component An amount such that the number of hydrogen atoms is 0.5 to 5;
(C) Platinum-based compound (A) It consists of a composition containing 0.1 to 1,000 ppm in terms of platinum atom mass with respect to component; and (D) 5 to 100 parts by mass of an inorganic filler. A silicone rubber molding material having a residual nitrogen content of 25 ppm or less.   (D) The silicone rubber molding material according to claim 1, wherein the inorganic filler is surface-treated with an organosilazane.   3. The surface treatment of the inorganic filler comprises mixing and stirring the mixture of the inorganic filler of the above component (A) and the component (D) and the organosilazane at a temperature of 160 ° C. or more for 3 hours or more. The silicone rubber molding material as described.