JP2003183503A - Organopolysiloxane composition for molding - Google Patents

Abstract

(57) Abstract: Condensation-type room-temperature-curable organopolysiloxane composition for providing a silicone rubber matrix having excellent release durability for cast molding of urethane resin or epoxy resin having improved properties. Providing things. (A) 100 parts by weight of an organopolysiloxane represented by the following general formula (I): Wherein R ¹ independently represents an unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 2 or more. (B) A hydrolyzable group bonded to a silicon atom in one molecule Organosilanes or siloxanes having at least three
0.5 to 20 parts by weight (C) Carboxyl group-containing compound 0.01 to 20 parts by weight (D) Curing catalyst Effective amount (E) 5 to 50 parts by weight of fine powder silica having a specific surface area of 50 m ² / g or more by BET method Organopolysiloxane composition for molding

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organopolysiloxane composition for molding, and a silicone rubber molded product as a master mold, especially as a master mold material for replicating an inverted mold made of urethane resin, epoxy resin, gypsum, etc. helpful,
The present invention relates to a condensation type room temperature curable silicone rubber composition for molding.

[0002]

2. Description of the Related Art It is known that a silicone rubber molded product is used as a reversal mother die to manufacture a replica, and a cast resin molded product such as an epoxy resin and a urethane resin manufactured in this manner is used for automobile parts, It is practically supplied as electrical and electronic parts, plastic models, crafts, etc. Recently, the properties such as flame retardancy and heat resistance of cast resin molded products obtained in this manner have been regarded as important. Therefore, various epoxy resins and urethane resins have various properties. Additives are added. As a result, the conventional silicone mother die has deteriorated the mold release durability, and the number of replicas that can be made from one mother die has been remarkably reduced.

Therefore, it is strongly desired to improve the mold release durability of the silicone rubber matrix to the casting resin, and in order to improve the mold release durability, the reinforcing hydrophilic silica filler added to the silicone rubber. _{a, (CH 3) 3 SiNHSi (} CH 3) 3,
_{(CH 3) 3 SiNHSi (CH} 3) 2 NHSi (CH 3) 3, (CF 3 C 2 H 4) (CH 3) 2 SiNHS
i (CH ₃ ) ₂ (C ₂ H ₄ CF ₃ ), etc. is treated with silazane to make it hydrophobic, or (CH ₂ = CH) (CH ₃ ) ₂ SiNHSi for improving the tear strength of silene rubber. (CH ₃ ) ₂ (CH = CH ₂ ), (CH ₃ ) ₃ Si
_{NHSi (CH 3) (CH =} CH 2) NHSi (CH 3) 3, (CH 3) 3 SiNHSi (CH 3) (CH =
CH ₂ ) [OSi (CH ₃ ) ₂ ] _a NHSi (CH ₃ ) ₃ (in the formula, a is 1 to 10),
(CH ₂ = CH) Si [NHSi (CH ₃ ) ₃ ] ₃ or the like is used in combination with the silazane to hydrophobize the reinforcing hydrophilic silica,
Alternatively, a method of re-treating the hydrophobic hydrophilic reinforcing silica with the compound is performed.

Japanese Unexamined Patent Publication No. 4-216864 describes an alkali metal hydroxide-containing silicone rubber composition having improved release durability. JP-A-5-279571 describes a composition containing a compound selected from organic tin compounds, organic titanium compounds and imidazole derivatives for improving releasability. JP-A No. 11-158385 describes the use of a radical scavenger for improving the release durability. However, these known techniques have not provided sufficiently satisfactory release durability. Incidentally, JP-A No. 11-158385 describes a composition in which a trifunctional or higher functional polyfunctional crosslinking agent and a bifunctional crosslinking agent are used in combination. There is no detailed description of the ratio, and it is not described that the combination results in a product having excellent release durability. Molds, which are cured products of these compositions, have relatively improved mold release durability, but as a silicone rubber matrix for urethane resins and epoxy resins having high physical properties, which are currently the mainstream of casting resins. The mold release durability of was not yet fully satisfactory.

Further, JP-A-61-225250 discloses a room temperature-curable organopolysiloxane composition containing an organic carboxylic acid, and JP-A-4-126768 discloses
Room-temperature-curable organopolysiloxane compositions containing organic fatty acids are disclosed, the former aiming at preventing avatars on the joint surface of architectural sealants and the latter on the pot life of the compositions. It is intended for extension.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to an organopolysiloxane composition for molding, which has solved the above-mentioned problems relating to the mold release durability as a silicone rubber matrix.

[0007]

That is, the present invention is (A) 100 parts by weight of organopolysiloxane represented by the following general formula [I]

[0008]

[Chemical 2] [In the formula, R ¹ independently represents an unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 2 or more] (B) A hydrolyzable group bonded to a silicon atom is contained in one molecule. Organosilane or siloxane having at least 3 0.5 to 20 parts by weight (C) Carboxyl group-containing compound 0.01 to 20 parts by weight (D) Curing catalyst effective amount (E) Fine powder silica having a specific surface area of 50 m ² / g or more by the BET method The present invention provides a mold-forming organopolysiloxane composition containing 5 to 50 parts by weight. The composition is a condensation type room temperature curable product, and as a cured product thereof, a silicone rubber mother die for casting a urethane resin or an epoxy resin and having remarkably improved mold release durability can be obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. [Component (A)] In the composition of the present invention, the organopolysiloxane of component (A) used as the base polymer is
The compound represented by the following general formula [I] is one kind alone or 2
Used in combination of two or more species.

[0010]

[Chemical 3] [In the formula, R ¹ independently represents an unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 2 or more. ]

Examples of R ¹ include lower alkyl groups having 8 or less carbon atoms such as methyl group, ethyl group, propyl group and butyl group; vinyl group, allyl group, isopropenyl group, butenyl group, hexenyl group, etc. Alkenyl group; (meth) acryloyl group or (meth) acryloyloxy group; cycloalkyl group such as cyclohexyl group; aryl group such as phenyl group, tolyl group, naphthyl group; aralkyl group such as benzyl group and 2-phenylethyl group And a group in which some or all of the hydrogen atoms of these groups are substituted with halogen, etc., such as chloromethyl group, 3,3,3-trifluoropropyl group, etc., having 1 to 10 carbon atoms, preferably carbon One having 1 to 8 atoms can be exemplified. Further, these monovalent hydrocarbon groups may be partially substituted with a hydroxyl group, if it is necessary in view of the characteristics. Of these, a methyl group, a phenyl group and a 3,3,3-trifluoropropyl group are preferable, and a methyl group is particularly preferable.

In the above general formula [I], n is 2
The above integers are preferred, and integers of 10 to 2,000, particularly 100 to 1,000 are preferred. The viscosity of this organopolysiloxane at 25 ° C is 10 to 500,000 cSt, especially 100
It is preferably in the range of up to 100,000 cSt.

The organopolysiloxane represented by the above general formula [I] is generally prepared by equilibrating an organocyclopolysiloxane with an alkali catalyst or an acid catalyst using water or a silanol group-containing low molecular compound as a terminating agent. can get. Examples of the alkali catalyst used here include potassium hydroxide, tetraalkylphosphonium hydroxide, tetraalkylammonium hydroxide, and the like, and examples of the acid catalyst include sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, and the like. It

Specific examples of the organopolysiloxane preferably used in the present invention include, but are not limited to, the followings. In the following, Ph represents a phenyl group.

[0015]

[Chemical 4] (N is an integer of 2 or more)

[0016]

[Chemical 5] (M and n'are integers of 1 or more)

[0017]

[Chemical 6] (M and n'are integers of 1 or more.)

[0018]

[Chemical 7] (M and n'are integers of 1 or more.)

[0019]

[Chemical 8] (N is an integer of 2 or more)

[0020]

[Chemical 9] (L, l ′, m and n ′ are each an integer of 1 or more.) Among the above, the following are particularly preferable.

[0021]

[Chemical 10] (N is an integer of 2 or more)

[Component (B)] In the present invention, the organosilane or siloxane used as the component (B) acts as a cross-linking agent. For this reason, one molecule of a hydrolyzable group bonded to a silicon atom is used. It is necessary to have at least 3 in it. That is, this hydrolyzable group is
It reacts with the silanol groups in the organopolysiloxane (A) to form a cured product having a three-dimensional structure and elastomeric properties.

Examples of such hydrolyzable groups include methoxy group, ethoxy group, propoxy group, butoxy group,
Alkoxy group such as methoxyethoxy group, ethoxyethoxy group; Acyloxy group such as acetoxy group, propionoxy group, butyroxy group, benzoyloxy group; isopropenyloxy group, isobutenyloxy group, 1-ethyl2-methylvinyloxy group, etc. Alkenyloxy groups; dimethylketoxime groups, methylethylketoxime groups, diethylketoxime groups, cyclopentanoxime groups, cyclohexanoxime groups and other iminoxy groups; N-methylamino groups, N-
Amino group such as ethylamino group, N-propylamino group, N-butylamino group, N, N-dimethylamino group, N, N-diethylamino group, cyclohexylamino group; N-methylacetamide group, N-ethylacetamide group , Amide groups such as N-methylbenzamide group; N, N-dimethylaminooxy group, N, N-
An aminooxy group such as a diethylaminooxy group can be mentioned, and among these, an alkoxy group and an alkenyloxy group are preferable, and an alkoxy group is particularly preferable.

In the present invention, such an organosilane that acts as a crosslinking agent has the formula: R ² _b SiX _4-b (b
Is 0 or 1. X is the hydrolyzable group, R ² is the same group as the above R ^1, and is preferably a methyl group, a vinyl group, or a phenyl group), specifically, methyltrimethoxysilane, Vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane,
Tetraethoxysilane, tetra (n-propoxy) silane,
Examples thereof include methyltris (propenoxy) silane, vinyltris (propenoxy) silane, phenyltris (1-methoxy-2-methylpropenoxy) silane, and the like. As the siloxane, these partially hydrolyzed condensates are preferably used. These may be used alone or in combination of two or more.

The amount of the component (B) used is 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the organopolysiloxane of the component (A). 0.5
When the amount is less than the weight part, the composition is not sufficiently cured, and it becomes difficult to obtain an elastomeric cured product,
In addition, disadvantages such as deterioration of mechanical properties of the cured product may occur. If more than 20 parts by weight is used,
There are cases in which the hardness of the cured product becomes too high and other disadvantages occur.

[Component (C)] In the present invention, the carboxyl group-containing compound used as the component (C) has the effect of improving the mold release durability of the silicone rubber matrix which is the object of the present invention. Specifically, formic acid, acetic acid, propionic acid, butyric acid, valerianic acid, caproic acid, caprylic acid, capric acid, lauric acid, partimic acid, stearic acid, and other carboxylic acids containing a linear or branched hydrocarbon group. Acids and carboxylic acids containing a phenyl group and a halogen group; fats and oils, specifically unsaturated aliphatic acids such as oil acid, linoleic acid and linolenic acid; dibasic acids, specifically oxalic acid and malonic acid , Succinic acid, glutaric acid,
Adipic acid, pimelic acid, suberic acid, azelaic acid,
Sebacic acid etc. are mentioned. Of these, monocarboxylic acids are preferable, and monocarboxylic acids having 5 to 20 carbon atoms are particularly preferable.

The compounding amount of the component (C) is 0.01 to 20 parts by weight, preferably 0.1 part by weight, based on the organosiloxane of the component (A).
~ 10 parts by weight is suitable. If it is 0.01 part by weight or less, the effect of improving the mold release durability is insufficient, and if it is 20 parts by weight or more, the surface of the cast molded product becomes rough, and the curing speed of the organopolysiloxane composition becomes slow, so that It becomes difficult to use.

[Component (D)] Used in the present invention
The component (D) is a curing catalyst used to accelerate the curing by the condensation / crosslinking reaction between the component (A) and the component (B),
Generally, the curing catalyst used in the condensation type room temperature curable silicone resin composition is used. For example, organic tin compounds such as dibutyltin dilaurate, dibutyltin dibenzyl maleate and dibutyltin dioctoate, metal salts of organic acids such as iron stearate and lead octylate, titanate esters such as tetraisopropyl titanate, and titanium acetylacetonate. Titanium chelate compounds such as, and mixtures thereof are preferably used.

These curing catalysts may be used in an effective amount necessary for curing, but generally, the total amount of components (A) to (C) is
It is desirable to use 0.01 to 10 parts by weight, particularly 0.1 to 5 parts by weight, per 100 parts by weight. If the blending amount is less than 0.01 parts by weight, the function of the curing catalyst will not be fully exerted, the curing time will be long, and the curing in the deep part of the rubber layer tends to be insufficient. If the amount is more than 10 parts by weight, the composition will have poor shelf life (pot life),
Further, properties such as heat resistance of the cured product tend to deteriorate.

[Component (E)] Next, the finely powdered silica as the component (E) which constitutes the organopolysiloxane composition for molding of the present invention is an elastomer by curing the composition of the present invention. It gives strength to things. In general, strength (particularly tear strength) is required to enable the replication of many cast resin molded products from one master mold including the case of reverse taper. Is required to have a specific surface area of 50 m ² / g or more according to the BET method, and the compounding amount is 5 to 50 parts by weight with respect to 100 parts by weight of the organopolysiloxane of the component (A), Preferably 1
It should be in the range of 0 to 40 parts by weight. If the amount is less than 5 parts by weight, the effect of improving the strength will be insufficient, and if the amount is more than 50 parts by weight, the fluidity will be remarkably poor and the releasability will be poor.

The fine powder silica may be hydrophilic or hydrophobic, but is preferably hydrophobic. As hydrophilic silica, Aerosil 30,20
0,300 [trade name, manufactured by Nippon Aerosil Co., Ltd.], Cabosil MS-5, MS-7 [trade name, manufactured by Cabot Corporation of the United States], Leorozil QS-102,103 [trade name, manufactured by Tokuyama Soda Co., Ltd.], Nipsil LP [trade name, Nihon Silica Co., Ltd.
[Made]. As the hydrophobic silica, Aerosil R-812, R-812S, R-972, R-974 [trade name, manufactured by Dexsa, Germany], Leorozil MT-10 [trade name, manufactured by Tokuyama Soda Co., Ltd.], Nipsyl Examples include SS series [trade name, manufactured by Nippon Silica Co., Ltd.].

When the hydrophilic silica is subjected to a hydrophobizing treatment,
Hexamethyldisilazane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane and the like may be pretreated silica with an organic silicon compound, or,
You may add the said organosilicon compound at the time of compounding.

[Component (F)] To the composition of the present invention, it is preferable to add (F) dimethyl silicone oil having both ends blocked with trimethylsilyl groups. The component (F) can adjust the viscosity of the composition and improve the releasability of the cured product. The amount of component (F) used is 100 parts of component (A).
It is preferably 0.1 to 20 parts by weight, particularly 0.2 to 10 parts by weight, based on parts by weight.

[Other compounding agents] In the present invention, in addition to the components (A) to (F) described above, various additives are added in order to improve the properties of the composition within a range not impairing the object of the present invention. Agents can be added. For example, carbon black or the like can be blended as a reinforcing filler, an anti-settling agent, or to impart electric conductivity. Further, as a semi-reinforcing filler, an extender, a heat conductive filler, quartz powder, fused quartz, spherical silica, diatomaceous earth, zeolite, calcium carbonate, titanium dioxide, iron oxide, alumina, spherical alumina, aluminum hydroxide, Aluminum nitride, magnesium sulfate, etc. can be added. Furthermore, in order to impart radiation shielding properties, carbonate,
Can be mixed with lead compounds such as hydroxide salts, etc., in addition to improve the heat resistance or flame retardancy of inorganic pigments, colorants such as organic dyes, cerium oxide, zinc carbonate, manganese carbonate, benzotriazole, platinum compounds, etc. Agents can also be included. Further, the composition of the present invention is a condensation curing type, in order to accelerate the curing, or to perform good curing in the deep portion, water, or methanol, ethanol, propanol,
It is also optional to add alcohols such as methyl cellosolve.

[0035]

EXAMPLES Examples and comparative examples will be shown below, but the present invention is not limited to the following examples. The parts in each example are parts by weight, and the viscosity is the viscosity at 25 ° C. The specific surface area is measured by the BET method.

<Preparation of Silicone Compound> [Preparation Example 1-1] 100 parts of dimethylpolysiloxane (viscosity: 5,000 cSt) whose both ends are blocked with silanol groups, and a non-treated dry type having a specific surface area of 300 m ² / g 20 parts of silica, 5 parts of hexamethyldisilazane and 2.5 parts of water were mixed in a kneader for 1 hour and heat-treated at 160 ° C. for 4 hours to prepare a silicone compound (Si-1).

Preparation Example 1-2 Other than changing 20 parts of untreated dry silica having a specific surface area of 300 m ² / g to 15 parts of hexamethyldisilazane treated product of dry silica having a specific surface area of 180 m ² / g In the same manner as in Preparation Example 1-1, a silicone compound (Si-2) was prepared.

[Preparation Example 1-3] 20 parts of untreated dry silica having a specific surface area of 300 m ² / g was changed to 22 parts of wet silica hexamethyldisilazane treated product having a specific surface area of 80 m ² / g. In the same manner as in Preparation Example 1-1, a silicone compound (Si-3) was prepared.

<Preparation of Curing Agent> [Preparation Example 2-1] 1.3 parts of dimethyltin diversate as a curing catalyst, 2.2 parts of phenyltrimethoxyxylan as a crosslinking agent, 1.0 part of caproic acid and dimethylpolysiloxane having trimethylsilyl groups at both ends. A curing agent (Ca-1) was prepared by mixing 0.5 parts.

[Preparation Example 2-2] 1.0 part of dibutyltin bishydroxysilicate as a curing catalyst, 2.2 parts of phenyltrimethoxysilane as a crosslinking agent, valproic acid ((C ₃ H ₇ ) ₂
CHCOOH) and 0.3 parts of dibutylpolysiloxane having trimethylsilyl groups at both ends were mixed to prepare a curing agent (Ca-2).

[Preparation Example 2-3] 1.6 parts of dimethyltin dioctoate as a curing catalyst, 2.2 parts of phenyltrimethoxyxylan as a cross-linking agent, 0.7 part of linoleic acid, and 0.5 part of dimethylpolysiloxane having trimethylsilyl groups at both ends were mixed. A curing agent (Ca-3) was prepared.

[Preparation Example 2-4] 1.6 parts of dimethyltin dioctoate as a curing catalyst, 2.2 parts of phenyltrimethoxysilane as a cross-linking agent, 1.0 part of malonic acid, and 0.2 parts of dimethylpolysiloxane having trimethylsilyl groups at both ends were mixed. To prepare a curing agent (Ca-4).

[Preparation Example 2-5] (for comparison) 1.3 parts of dimethyltin diversate as a curing catalyst, 2.2 parts of phenyltrimethoxysilane as a cross-linking agent, and 1.5 parts of dimethylpolysiloxane having trimethylsilyl groups at both ends were mixed and compared. A curing agent (Ca-5) was prepared.

[Preparation Example 2-6] (for comparison) Dibutyltin bishydroxysilicate as a curing catalyst
1.0 part, phenyltrimethoxylan 2.2 as a cross-linking agent
And 1.8 parts of dibutyl polysiloxane having trimethylsilyl groups at both ends were mixed to prepare a comparative curing agent (Ca-6).

Preparation Example 2-7 (for comparison) 1.6 parts of dimethyltin dioctoate as a curing catalyst, 2.2 parts of phenyltrimethoxysilane as a cross-linking agent, and 1.2 parts of dimethylpolysiloxane having trimethylsilyl groups at both ends were mixed and compared. A curing agent (Ca-7) was prepared.

-Examples / Comparative Examples-Example 1 The above silicone compound (Si-1) and the above curing agent (C
a-1) was mixed at a ratio of 100: 5 (weight ratio), stirred well, degassed under vacuum, molded into a sheet having a thickness of 2 mm, and then cured at 25 ° C for 3 days, and then JIS Hardness, elongation, tensile strength, and tear strength were measured according to K6301.
The measurement results are shown in Table 1. On the other hand, a concave mother die is molded in the same manner, and a urethane resin (product name: 301
(7, manufactured by H & K Co.) was cast and cured at 25 ° C. for 3 days, and the number of mold makings until the urethane resin molded product obtained adhered to the silicone mother mold was measured. Table 1 shows the number of times the pattern was taken.

Comparative Example 1 Each measurement was carried out in the same manner as in Example 1 except that the above curing agent (Ca-1) was changed to the above comparative curing agent (Ca-5). The results are shown in Table 1.

Example 2 The above silicone compound (Si-1) was added to the above silicone compound (Si-2), and the above curing agent (Ca-
Each measurement was performed in the same manner as in Example 1 except that 1) was changed to the above curing agent (Ca-2). The results are shown in Table 1.

Comparative Example 2 Each measurement was carried out in the same manner as in Example 2 except that the above curing agent (Ca-2) was changed to the above comparative curing agent (Ca-6). The results are shown in Table 1.

Example 3 The above silicone compound (Si-1) was added to the above silicone compound (Si-3), and the above curing agent (Ca-
Each measurement was performed in the same manner as in Example 1 except that 1) was changed to the above curing agent (Ca-3). The results are shown in Table 1.

Example 4 Each measurement was carried out in the same manner as in Example 3 except that the above curing agent (Ca-3) was changed to the above curing agent (Ca-4). The results are shown in Table 1.

Comparative Example 3 Each measurement was carried out in the same manner as in Example 3 except that the above curing agent (Ca-3) was changed to the above comparative curing agent (Ca-7). The results are shown in Table 1.

[0053]

[Table 1]

[0054]

The organopolysiloxane composition for molding according to the present invention is a condensation type room temperature curable composition, and a silicone rubber matrix for resin casting obtained by curing the composition is
The release durability is superior to that of the conventional one, and in particular, many reversal replicas can be manufactured by cast molding of urethane resin or epoxy resin, and the effect is remarkable.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/09 C08K 5/09 5/541 B29K 63:00 // B29K 63:00 75:00 75:00 C08K 5/54 (72) Inventor Hiroshi Mogi 1 1 Hitomi, Osamu Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Silicon Electronics Materials Research Laboratory F-term (reference) 4F071 AA67 AB26 AC09 AC16 AD02 AD06 AE03 BA02 BB01 BC04 4F202 AA39 AA42 AJ05 AJ11 CA01 CB01 CD01 CD30 4J002 CP032 CP061 DJ019 EC078 EE048 EF037 EF047 EF057 EF067 EG048 EX016 EX036 EX076 EZ048 FA089 FD010 FD019 FD130 FD158 GT00

Claims (4)

[Claims] 1. (A) 100 parts by weight of an organopolysiloxane represented by the following general formula [I]: [In the formula, R ¹ independently represents an unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 2 or more] (B) A hydrolyzable group bonded to a silicon atom is contained in one molecule. Organosilane or siloxane having at least 3 0.5 to 20 parts by weight (C) Carboxyl group-containing compound 0.01 to 20 parts by weight (D) Curing catalyst effective amount (E) Fine powder silica having a specific surface area of 50 m ² / g or more by the BET method An organopolysiloxane composition for molding, which contains 5 to 50 parts by weight. 2. The molding organopolysiloxane composition according to claim 1, wherein the component (C) is a monocarboxylic acid having 5 to 20 carbon atoms. 3. The organopolysiloxane composition for molding according to claim 1, which further comprises (F) 0.1 to 20 parts by weight of dimethyl silicone oil having both ends blocked with trimethylsilyl groups. 4. A urethane resin or epoxy resin casting mold made of a cured product of the organopolysiloxane composition for molding according to any one of claims 1 to 3.