JPH09235469A - Cork-particle-containing addition-curable silicone composition and molded stopper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a silicone composition which can give cured products serving as molded stoppers quite harmless to the object to be held, having excellent quality stability including sealability, excellent productivity, and the so-called corky appearance of a quality article and desirably used as stoppers of bottles for various beverages, especially choice-quality whiskies and wines. SOLUTION: This composition is prepared by mixing an addition-curable organopolysiloxane composition which comprises an organopolysiloxane having at least two Si-bonded aliphatic unsaturated hydrocarbon groups in the molecule, an organohydrogenpolysiloxane having at least two Si-bonded hydrogen atoms in the molecule, and platinum or its compound and which can give a cured product having a tensile strength of 50kgf/cm<2> or above and a resiliency of 40% or above with 5-25 pts.wt. cork particles having a mean particle diameter of 0.2-10mm. A molded stopper is made by curing this composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has a high level of safety with respect to an enclosed object, excellent quality stability including sealing property, excellent productivity, and a high-class cork-like feeling. The present invention relates to a cork particle-containing addition-curable silicone composition capable of providing a molding stopper suitable for use as a stopper for various beverages, especially high-grade whiskey, wine, etc., and a molding stopper made of a cured product of the composition.

[0002]

2. Description of the Related Art The use of cork material as a sealing material (plug) for beverage containers is old, and is widely used for wine, crown discs, and Western liquor. In recent years, in such Western sake and wine stoppers, with the improvement of the quality level, the bleeding and leaking of the liquid, which has been overlooked because it is a natural material, has become impossible. For this reason, the sealing material (plug) made of cork material produces many defective products in order to select non-defective products, which leads to high cost and quality variations have been highlighted.

On the other hand, the cork material has good original properties (soft and light, good compression recovery, good water resistance, heat resistance, acid resistance, solvent resistance, etc.) as a stopper. It has excellent advantages such as good appearance as a stopper, good feel when unplugged, and high quality. Furthermore, cork is an ideal material from the standpoint of nature conservation, as it is manufactured using the skin of cork oak rather than felling trees. This is also the reason why it is difficult to use a synthetic resin stopper typified by a polyester resin or the like, which is partially put into practical use as a substitute, as a stopper for particularly high-grade Western sake.

Therefore, a material produced by molding cork particles using a binder, that is, a stopper produced from pressed cork, has been studied and put into practical use. Typical binders for the pressed cork are urethane type and epoxy type. Binders are often used.

However, urethane-based binders have problems such as carcinogenicity due to isocyanate and poor dimensional stability due to shrinkage, which leads to deterioration in sealing properties. Epoxy-based binders lack flexibility and impact resilience. It was the current situation that breakage is likely to occur when unplugging, and when any binder is used as a plug, many problems with respect to important functions occur. In addition, such a compressed cork stopper has a drawback that it takes a lot of time and labor in a processing step such as dimensioning after molding, resulting in a high cost.

Further, the use of silicone compositions has been investigated in order to solve the above problems, especially safety and sealing properties,
For example, Japanese Utility Model Publication No. 63-147456 and Japanese Utility Model Publication No. 63-147
Japanese Patent No. 147457 discloses an addition-curable silicone rubber-coated cork stopper. However, this is a silicone rubber-coated plug made by insert molding of a cork stopper, and since the main part is the cork stopper itself, it still has the above-mentioned drawbacks of the cork stopper. Was required, and there was a problem in terms of productivity and cost.

Further, Japanese Patent Laid-Open No. 4-77556 discloses that
As a molding stopper using the silicone composition itself as a binder, a molding stopper composed of a room temperature curable organopolysiloxane composition and cork particles is disclosed. According to this,
In addition to improving the performance while maintaining the cork feel, it is also advantageous in terms of cost because it does not require cork molding as in the above example in terms of production, but since the organopolysiloxane composition is a room temperature curable type, it is considerably difficult to cure. However, it is difficult to say that the stability of performance is satisfactory due to the condensation by-product generated in the curing reaction, and it is not sufficient. The development of a quality molded plug was desired.

The present invention has been made in view of the above circumstances, and is highly safe with respect to an enclosed object, excellent in quality stability including sealing property, excellent in productivity, and has a so-called high-class cork feel. An object of the present invention is to provide a cork particle-containing addition-curable silicone composition that gives a molded plug having a feeling and a molded plug formed of a cured product of this composition.

[0009]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of extensive studies conducted by the present inventor to achieve the above object, (a) an aliphatic unsaturated hydrocarbon bonded to a silicon atom in one molecule Organopolysiloxane containing two or more groups (b) Organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms in one molecule (c) Platinum or platinum compound, and tensile strength An addition-curable organopolysiloxane composition that gives a cured product having a rebound resilience of 40% or more and 50 kgf / cm ² or more is used as a binder, and (d) the average particle diameter is 0.
When a molding stopper is formed from a cured product of a cork particle-containing addition-curable silicone composition containing 5 to 25 parts by weight of 2 to 10 mm cork particles, the safety is high with respect to the material to be encapsulated and the sealing property is included. The inventors have found that a molding stopper having excellent quality stability, excellent productivity, and a so-called high-class feeling of cork can be obtained, and the present invention has been accomplished.

Therefore, the present invention provides (a) an organopolysiloxane containing two or more aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule, and (b) hydrogen bonded to a silicon atom in one molecule. Organohydrogenpolysiloxane containing two or more atoms (c) Addition-curable organopolysiloxane containing platinum or a platinum compound and giving a cured product having a tensile strength of 50 kgf / cm ² or more and a repulsion elastic modulus of 40% or more. (D) 5 to 25 cork particles having an average particle size of 0.2 to 10 mm with respect to 100 parts by weight of the composition
Provided is a cork particle-containing addition-curable silicone composition, characterized by containing parts by weight, and a molding stopper made of a cured product of the cork particle-containing addition-curable silicone composition.

The present invention will be described in more detail below. The first component of the addition-curable silicone composition containing cork particles according to the present invention comprises two aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule. It is an organopolysiloxane containing one or more, and this component is the main material of the composition of the present invention.

As the above-mentioned organopolysiloxane, it is preferable to use one represented by the following average composition formula (1).

R ¹ _a R ² _b SiO _{[4- (a + b)] / 2} (1) (wherein R ¹ is a monovalent aliphatic unsaturated hydrocarbon group, R ²
Is a substituted or unsubstituted monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group, and a and b are 0 <a ≦ 1 and 1 ≦, respectively.
It is a positive number that satisfies b <3 and 1 <a + b <3. )

In the organopolysiloxane of the above formula (1), R ¹ is preferably a monovalent aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, more preferably 2 to 4 carbon atoms. Vinyl group, allyl group, propenyl group,
Examples thereof include alkenyl groups such as an isopropenyl group, a butenyl group, an isobutenyl group, a hexenyl group and a cyclohexenyl group, and a vinyl group is particularly preferable. R ² is a substituted or unsubstituted monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group, preferably having 1 to 12 carbon atoms, more preferably having 1 to 8 carbon atoms, such as a methyl group. , Ethyl group, propyl group, butyl group, hexyl group, octyl group,
Alkyl group such as decyl group, aryl group such as phenyl group and tolyl group, aralkyl group such as benzyl group and phenylethyl group, or part or all of hydrogen atoms of these hydrocarbon groups such as fluorine, bromine and chlorine. Examples thereof include those substituted with a halogen atom or a cyano group, for example, a chloromethyl group, a bromoethyl group, a trifluoropropyl group, a cyanoethyl group and the like, and a methyl group, a phenyl group and a trifluoropropyl group are particularly preferable.

In the above formula (1), the respective substituents bonded to the silicon atom may be different or the same, but each molecule contains two or more aliphatic unsaturated hydrocarbon groups. It is necessary that this aliphatic unsaturated hydrocarbon group be bonded to either the terminal of the molecular chain or the silicon atom in the middle of the molecular chain, or to both of them, but especially Those having an aliphatic unsaturated hydrocarbon group on silicon atoms at both ends of the molecular chain are preferable.

Further, a and b are 0 <a ≦ 1 and 1 ≦, respectively.
Positive numbers satisfying b <3, 1 <a + b <3, but preferably 0.0001 ≦ a ≦ 0.2, 1.4 ≦ b ≦ 2.2,
1.5 ≦ a + b ≦ 2.25, more preferably 0.000
2 ≦ a ≦ 0.1, 1.8 ≦ b ≦ 2.1, 1.8 <a + b
≦ 2.2.

In the molecular structure of the organopolysiloxane of the above formula (1), generally, the main chain portion is basically composed of repeating diorganosiloxane units, and both ends of the molecular chain are blocked with triorganosiloxy units. Although it is a straight-chain diorganopolysiloxane, it may have a branched or cyclic skeleton, and a triorganosiloxy unit and S
It may be a three-dimensional reticulated resinous material containing i0 _4/2 units.

The molecular weight of the above-mentioned organopolysiloxane is appropriately selected, but from the viewpoint of being cured into a rubber-like elastic body and providing a liquid silicone rubber composition, 2
Viscosity at 5 ° C is 100 to 300,000 centipoise (cp
s), especially 1000 to 100000 cps. In particular, when the composition is in a liquid state, it can be continuously molded by a liquid injection molding machine which is commonly used as a molding method, and thus is extremely effective in terms of production.

Next, the organohydrogenpolysiloxane having 2 or more, preferably 3 or more, hydrogen atoms (that is, SiH groups) bonded to a silicon atom in one molecule of the component (b) is the first component. It is a component that serves as a cross-linking agent for organopolysiloxane, and has the following average composition formula (2) R ³ _c H _d SiO _{[4- (c + d)] / 2} (2) (wherein R ³ is substituted or It is an unsubstituted monovalent hydrocarbon group, and c and d are 0.8 ≦ c ≦ 2.2, respectively.
It is a positive number that satisfies 0.002 ≦ d ≦ 1.0 and 0.8 <c + d ≦ 3. Those shown in () are preferably used.

In the above formula (2), R ³ may be the same as those exemplified above for R ¹ and R ² , but preferably has an aliphatic unsaturated bond similar to R ^2. 1 to 8 carbon atoms, more preferably 1 carbon atom
To alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, an aryl group such as a phenyl group and a tolyl group, an aralkyl group such as a benzyl group, a phenylethyl group or the like. A hydrocarbon group in which some or all of the hydrogen atoms have been replaced with a halogen atom or a cyano group, such as a chloromethyl group, a trifluoropropyl group,
Examples thereof include a cyanoethyl group. Each substituent bonded to the silicon atom may be the same or different.

Further, c and d are 0.8≤c≤2.
2, a positive number satisfying 0.002 ≦ d ≦ 1.0 and 0.8 <c + d ≦ 3, preferably 1 ≦ c ≦ 2, 0.01 ≦
d <1.0 and 1.8 ≦ c + d ≦ 2.5.

The structure of the above organohydrogenpolysiloxane is generally linear, but it may have a branched or cyclic skeleton, and has a three-dimensional network structure. Is also good.

The molecular weight of the organohydrogenpolysiloxane of the above formula (2) is not particularly limited, but its viscosity at 25 ° C. is 1 to 10000 cps, especially 3 to.
It is desirable that the range is 1000 cps.

The amount of the organohydrogenpolysiloxane blended is such that the ratio of the number of moles of silicon atom-bonded hydrogen atoms to the number of moles of silicon atom-bonded unsaturated hydrocarbon groups in the addition-curable silicone composition is 0.5: 1. ~ 20: 1, especially 1: 1 ~
The amount is preferably 3: 1. When the number of moles of silicon atom-bonded hydrogen atoms is less than 0.5 with respect to the number of moles of silicon atom-bonded unsaturated hydrocarbon group, the addition-curable silicone composition may not be sufficiently cured, and when it is greater than 20. May foam.

Further, as the platinum or platinum compound as the component (c), those generally known as addition reaction catalysts can be used, but alcohol-modified chloroplatinic acid, chloroplatinic acid and olefin are added considering dispersibility. It is preferable to use a complex of chloroplatinic acid and a complex of chloroplatinic acid and vinylsiloxane. The amount of platinum or platinum compound added is a catalytic amount, and is usually (a)
5 to 500 ppm in terms of platinum relative to the components, especially 10 to
Addition within the range of 200 ppm is desirable.

In the addition-curable silicone rubber composition, quartz powder, diatomaceous earth, etc. may be added as an optional component other than the above-mentioned main components, for example, when it is necessary to impart strength to the composition.
It is effective to add a semi-reinforcing filler such as calcium carbonate, alumina or carbon black, or a reinforcing filler such as fine powder silica. As such a reinforcing filler, specifically, as a hydrophilic silica, Aerosil 13
0, 200, 300 (Degus, manufactured by Nippon Aerosil Co., Ltd.)
sa company), Cabosil MS-5, MS-7 (C
abot), Rheorosil QS-102,
103 (manufactured by Tokuyama Soda Co., Ltd.), Nipsil LP (manufactured by Nihon Silica Co., Ltd.) and the like are exemplified, and as hydrophobic silica, Aero
sil R-812, R-812S, R-972, R-
974 (manufactured by Degussa), Rheorosil
Examples include MT-10 (manufactured by Tokuyama Soda Co., Ltd.) and Nipsil SS series (manufactured by Nippon Silica Co., Ltd.). In addition, these may be used individually by 1 type or in combination of 2 or more types.

The surface of these silica fillers may be treated with, for example, a chain organopolysiloxane, a cyclic organopolysiloxane, or an organosilazane such as hexamethyldisilazane. If necessary, a heat resistance improver such as carbon, a colorant, iron oxide or cerium oxide may be added.

Further, in order to put these materials into practical use,
When it is necessary to adjust the curing time, vinyl group-containing organopolysiloxanes such as vinylcyclotetrasiloxane, acetylene alcohols such as ethynylcyclohexanol and their silanes, siloxane modified products and mixtures thereof are used as a control agent. It doesn't matter.

The addition amount of these optional components can be a usual amount within the range that does not impair the effects of the present invention.

The addition-curable organopolysiloxane composition of the present invention containing the above-mentioned components (a) to (c) functions as a binder for cork particles, and is therefore particularly broken during tapping of the molding plug or removed during molding. From the standpoint of preventing breakage when molding
The cured product has a tensile strength of 50 at least 25 ° C.
kgf / cm ² or more, usually 50 to 120 kgf / cm ² ,
It is necessary to have a strength of about 70 to 100 kgf / cm ^{2, and in} order to obtain a sufficient sealing property, the impact resilience at least at 25 ° C. is 40% or more, usually 40 to 100%, preferably 60 to It should be about 90%. The tensile strength of the cured product is 50 kgf / cm ²
If it is less than or less than 40% or the impact resilience is less than 40%, the damage resistance and sealing property of the produced molded plug are deteriorated, and practical durability cannot be obtained.

The addition-curable silicone composition containing cork particles of the present invention is prepared by mixing the above-mentioned addition-curable silicone composition as a binder with the cork particles having a specific particle size.

In this case, cork particles having an average particle size of 0.2 to 10 mm, preferably 0.5 to 5 mm are used. If the average particle size exceeds 10 mm, the resulting dispersion becomes non-uniform and the quality of the obtained molding plug becomes unstable. If the average particle size is less than 0.2 mm, the moldability is significantly impaired, resulting in poor molding.

Further, when the addition-curable silicone composition is in a liquid state, for example, the viscosity at 25 ° C. is 50 to 500.
00 Poise, preferably 100-200
In the case of about 00 poise, particularly about 200 to 10,000 poise, this composition penetrates into the porous cork and sufficient adhesion with the cork interface can be obtained. It is effective to use cork grains that have been previously treated with a primer (for example, treated with Primer No. 4 manufactured by Shin-Etsu Chemical Co., Ltd.) for the purpose of imparting characteristics.

The addition ratio of the addition-curable silicone composition and the cork particles is 5 to 25 parts, preferably 8 to 20 parts, based on 100 parts (parts by weight, the same applies hereinafter) of the addition-curable silicone composition. The range is 25 and the amount of cork grains is 25.
If it exceeds 5 parts, mixing and dispersion will be hindered, and if it is less than 5 parts, the cork feeling is particularly impaired.

The method for mixing the addition-curable silicone composition and the cork particles is not particularly limited and may be any ordinary method. For example, a universal mixing stirrer (manufactured by Shinagawa Kogyo Co., Ltd.)
Can be mixed using such as.

The addition-curable silicone composition containing cork particles of the present invention can be molded by various molding methods such as ordinary compression molding method, extrusion molding method and injection molding method, but the composition is particularly liquid. In this case, the injection molding method is extremely effective in terms of productivity, such as automation. The curing condition is not particularly limited, but is usually 0.5 to 30 at 100 to 180 ° C.
It can be minutes.

[0037]

INDUSTRIAL APPLICABILITY The addition-curable silicone composition containing cork particles of the present invention has excellent physical properties such that the cured product containing cork particles has a tensile strength of 15 kgf / cm ² or more and a repulsion elastic modulus of 40% or more. When a molded plug is formed from this cured product, it is highly safe for the enclosed material, has excellent quality stability including sealing properties, and has excellent productivity, and has a so-called high-class feeling of cork. It can be a stopper. Therefore, this molded stopper can be suitably used as a stopper for various beverages, especially high-grade whiskey, wine and the like.

[0038]

EXAMPLES The present invention will be specifically described below with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples. All parts in each example are parts by weight.

[Reference Examples 1 and 2] The viscosity at 25 ° C. was 3
Dimethylpolysiloxane containing vinyl groups at both ends of 0000 cps (vinyl value 0.0036 mol / 100 g) 80
Part, Aerosil 300 (fumed silica manufactured by Nippon Aerosil Co., Ltd.) 40 parts, hexamethyldisilazane 8 parts,
2 parts of water were mixed, uniformly mixed by a kneader kneader, and further mixed by heating at 160 ° C. for 4 hours, and the obtained silicone rubber base was subjected to dispersion treatment with a three-roll mill. Then, 100 parts of the silicone rubber base had a viscosity of 7 at 25 ° C.
15 parts of dimethylpolysiloxane (vinyl value 0.135 mol / 100 g) containing a vinyl group in the side chain of both ends trimethylsilyl group blocking of 00 cps, 0.2 part of vinyl siloxane complex of chloroplatinic acid (platinum concentration 1%) After mixing and uniformly mixing with a universal mixing stirrer, the mixture was filtered through a wire mesh of 150 mesh to obtain a composition (A).

100 parts of the silicone rubber base obtained in the same manner as above had a viscosity at 25 ° C. of 700 cps.
Dimethylpolysiloxane containing vinyl groups on the side chains of both ends of trimethylsilyl group (vinyl value 0.135 m
ol / 100g), the viscosity at 25 ° C is 15c.
10 parts of ps methylhydrogenpolysiloxane (SiH equivalent 0.0069 mol / g) and 0.1 part of ethynylcyclohexanol were mixed and uniformly mixed with a universal mixing stirrer, and then filtered through a 150 mesh wire net, A composition (B) was obtained.

Next, the viscosity at 25 ° C. is 100,000.
cps dimethylpolysiloxane containing vinyl groups at both ends (vinyl value 0.0025 mol / 100 g) 15 parts, 2
Dimethylpolysiloxane containing vinyl groups at both ends with a viscosity at 5 ° C of 5000 cps (vinyl value 0.006 mol
/ 100 g) 40 parts, vinyldimethylsiloxy units:
(CH ₂ ═CH) (CH ₃ ) ₂ SiO _1/2 unit, trimethylsiloxy unit: (CH ₃ ) ₃ SiO _1/2 unit and SiO _4/2
Silicone resin consisting of units (vinyl value 0.044
(mol / 100 g) 45 parts, and 0.15 parts of vinyl siloxane complex of chloroplatinic acid (platinum concentration 1%) were mixed and uniformly mixed with a universal mixing stirrer, and then filtered through a wire mesh of 150 mesh to obtain a composition. (C) was obtained.

Also, 100 parts of the silicone rubber base obtained in the same manner as above had a viscosity of 100,000 at 25 ° C.
cps dimethylpolysiloxane containing vinyl groups at both ends (vinyl value 0.0025 mol / 100 g) 15 parts, 2
Dimethylpolysiloxane containing vinyl groups at both ends with a viscosity at 5 ° C of 5000 cps (vinyl value 0.006 mol
/ 100 g) 40 parts, vinyldimethylsiloxy units:
(CH ₂ ═CH) (CH ₃ ) ₂ SiO _1/2 unit, trimethylsiloxy unit: (CH ₃ ) ₃ SiO _1/2 unit and SiO _4/2
Silicone resin consisting of units (vinyl value 0.044
mol / 100g) 45 parts, viscosity at 25 ° C is 15
cps methyl hydrogen polysiloxane (SiH
20 parts of an equivalent of 0.0069 mol / g) and 0.1 part of ethynylcyclohexanol were mixed and uniformly mixed with a universal mixing stirrer, and then filtered through a wire mesh of 150 mesh to obtain a composition (D).

25 of the compositions (A) to (D) obtained above
The viscosity at ° C was measured (in accordance with JISK7117). Then, each composition is mixed in a weight ratio of (A):
(B) = 1: 1 (Reference Example 1), (C) :( D) = 1: 1
The mixture was mixed in (Reference Example 2), and the curability was measured with a rheometer (manufactured by Toyo Seiki Co., Ltd.). Further, the mixture mixed in the same mixing ratio is press-molded under a curing condition of 120 ° C. for 10 minutes to prepare a sheet-shaped cured product sample, and the physical properties are determined according to each JIS method as follows. It was measured. Hardness (JIS C2123) Tensile strength (JIS K6301) Elongation (JIS K6301) Impact resilience (JIS K6301) Tear strength (JIS K6301)

Further, the above cured product sample was immersed in a 45% ethanol solution at 50 ° C. for 3 weeks and taken out, and then the taste and smell of the immersion liquid were sensory evaluated. After taking this out,
The above-mentioned physical property test was conducted on a cured product sample which was naturally dried for 2 hours and further dried at 60 ° C for 2 hours. The above measurement results are shown in Table 1. In Table 1, T ₁₀ , T ₉₀
Is the time until the torque reaches 10% and 90%, respectively, when the torque after 2 minutes from the start of curing is 100%.

From the results shown in Table 1, the compositions prepared in Reference Examples 1 and 2 are extremely excellent in curability, and the cured products have a tensile strength of 50 kgf / cm ² or more and a repulsion elastic modulus of 40% or more. It was confirmed that various properties were excellent, and it had good properties even after immersion in ethanol, and was extremely stable with respect to the encapsulated material.

[0046]

[Table 1]

[Examples 1 and 2, Comparative Examples 1 and 2] The compositions of Reference Examples 1 and 2 and cork particles having an average particle size of 1 mm were uniformly mixed in the following mixing ratio (weight ratio) with a universal mixing stirrer. Mix 1
Press molding is performed under curing conditions of 20 ° C. for 5 minutes to prepare a sheet-shaped cured product, and press molding is performed under the same conditions using a prepared mold for a molding plug, a diameter of 25.5 mm and a height of 21.
A molded plug of mm was obtained.

(A): (B): Cork grains = 50: 50: 8 (Example 1) (C): (D): Cork grains = 50:50:15 (Example 2)

For comparison, an epoxy resin was used as a binder, and 100 parts of the cork particles were mixed with 7 parts of an epoxy resin (# 1500 manufactured by Cemedine Co., Ltd.) and 13 parts of polyethylene glycol in the same manner. Press molding was performed under a curing condition of time to obtain a sheet-shaped cured product and a molding plug (Comparative Example 1). A natural cork was punched out to obtain a plug having the same shape as a control sample (Comparative Example 2).

Of the obtained samples, the sheet-like sample was measured for tensile strength (JIS K6301), and the molded plug sample was measured for impact resilience (JIS K6301).

Further, each sample was added to a 45% ethanol solution in an amount of 5
After immersion for 3 weeks at 0 ° C. and taking out, the immersion liquid was subjected to a sensory test. Next, the taken-out sample was naturally dried for 8 hours, further dried at 60 ° C. for 2 hours, cooled, and then similarly measured for tensile strength and impact resilience. Table 2 shows the results.

Next, with respect to the sealing performance, which is an important characteristic of the obtained molded plug, the creep value and the compression fixing rate over 63 days were measured. First, the creep value was measured under the following conditions. The results are shown in Table 3 and FIG. Creep value : A molding stopper having a diameter of 25.5 and a height of 21 mm is compressed to a diameter of 23.5 mm, dipped in 43% alcohol in a desiccator, and at a room temperature (25 ° C.) 1 to 63.
Held for days. Remove the load on each number of days shown in Table 3,
The creep value after 1 minute was measured by a creep measuring machine (manufactured by Kyowa Denki Co., Ltd., model SDB-410CS3).

Furthermore, the compression fixation ratio was measured under the following conditions.
Specified. The results are shown in Table 4 and FIG. Compression fixed rate : 3 after removing the load under the creep value measurement conditions
The compression fixation ratio after 0 minutes was measured with a caliper.

From the results shown in Tables 2 to 4, the silicone composition containing cork particles of the present invention has a tensile strength of 15 kgf / cm ² or more and a repulsion elastic modulus of 40% or more and is excellent in various performances, and the performance is stable against ethanol. Giving a cured product, and molding plugs made from this cured product are very good in terms of application, such as stoppering, damage at the time of unplugging, and excellent sealing property, and there is no problem with odor, etc. It has been found that it can be used as a stopper.

[0055]

[Table 2]

[0056]

[Table 3]

[0057]

[Table 4]

[Brief description of drawings]

FIG. 1 is a graph showing the creep value over time of the molded plugs obtained in Examples and Comparative Examples.

FIG. 2 is a graph showing the time-dependent compression fixation ratios of the molded plugs obtained in Examples and Comparative Examples.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C08L 97:02) (72) Inventor Toshiyuki Ashihara 338 Enami, Okayama, Okayama Uchiyama Industrial Co. Okayama (72) Inventor Hideki Yamashita 1-11-4 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Shin-Etsu Chemical Co., Ltd.Osaka Branch (72) Inventor Masanobu Miyakoshi 1 Hitomi, Odaimi, Matsuida-cho, Usui-gun, Gunma 10 Shin-etsu Chemical Industry Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Takeo Yoshida 1 Hitomi, Osamu Matsuida-cho, Usui District, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (2)

[Claims] 1. An organopolysiloxane containing (a) two or more aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule. (B) Two hydrogen atoms bonded to a silicon atom in one molecule. Addition-curable organopolysiloxane composition containing the above-mentioned organohydrogenpolysiloxane (c) platinum or a platinum compound and giving a cured product having a tensile strength of 50 kgf / cm ² or more and a repulsion elastic modulus of 40% or more. (D) 5 to 25 cork particles having an average particle size of 0.2 to 10 mm
An addition-curable silicone composition containing cork particles, characterized in that it contains 100 parts by weight. 2. A molding stopper made of a cured product of the addition-curable silicone composition containing cork particles according to claim 1.