JPH03152138A - Buffer vibration-proof material made of silicone gel and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject buffer vibration-proof material having improved air permeability and buffer vibration-proof property without losing the characteristic of a silicone gel and useful as a seat material, etc., by mixing the men- cured raw liquid of the silicone gel with granules, curing the mixture and subsequently eluting the granules from the cured silicone gel to form pores. CONSTITUTION:For example, a mixed solution comprising (A) a diorgano- polysiloxane and (B) an organo hydrogen polysiloxane having a viscosity of <=5000cSt at 25 deg.C, containing at least three hydrogen atoms directly bonded to Si atoms in one molecule and having a molar ratio of 0.1-2.0 between the alkenyl groups in the component A and the hydrogen atoms and forming a cured product having a needle penetration degree of 5-250 is mixed with (c) granules (e.g. salt) soluble in a solvent having a dissolution constant of >=9.9 in a weight rative of 1:2, cured and subsequently placed in (D) a solvent (e.g. water) to elute the granules C, thereby providing the objective buffer vibration- proof material.

Description

[Detailed description of the invention]

(Purpose of the invention)

[Industrial application field]

The present invention provides a method for manufacturing a silicone gel cushioning and vibration isolating material that improves the properties of silicone gel, which has come to be used as a material for cushioning, vibration isolation, packaging, etc., and a silicone gel cushioning and vibration isolation material with improved properties. It is used between wood.

[Background of the invention]

'Recently, the excellent cushioning and vibration-proofing properties of silicone gel have been reconsidered, and in particular, silicone gel, which is an addition reaction type silicone copolymer, is used as a cushioning pad in the soles of shoes and various sports equipment, and is also used in various rotating devices and It is also expected to be used as a special packaging material for high-precision, high-value-added products such as insulators for office automation equipment and precision measuring instruments. In particular, JlS (K-2207-198050g load)
Silicone gel with a penetration degree of about 6 to 250 measured from D is preferable because it has excellent cushioning and vibration-proofing properties, but it is expensive and relatively heavy with a specific gravity of nearly 1. there were. Of course, by incorporating microscopic hollow spheres, etc., it is possible to lower the cost and specific gravity, and at the same time improve the cushioning and vibration-proofing properties, but even these composite silicone gels do not have air permeability. Therefore, it is not suitable for use as a material for parts that come into direct contact with the human body, such as seat sheet materials and helmet interior materials. However, at present, it is difficult to obtain foamed silicone gel, and even foams made of conventional materials cannot match the characteristics of silicone gel.

[Technical matters tried during development]

Therefore, the present invention was made in view of the current situation, and it is an object of the present invention to form open pores in a silicone gel to ensure air permeability without losing the properties of the silicone gel. This is an attempt to obtain a cushioning and vibration-isolating material made of silicone gel that also has improved cushioning and vibration-isolating properties by forming pores. (Structure of the invention)

[Means to achieve the purpose]

That is, the method for manufacturing a silicone gel shock absorbing material, which is the first invention related to the present application, is a method for manufacturing a silicone gel shock absorbing material that does not inhibit the hardening of the silicone gel that hardens to a penetration of about 5 to 260, and that does not inhibit the hardening of the silicone gel. The solubility constant (Solu-bility P a
a step of mixing granules of a substance that can be dissolved in a solvent with a particle size of 9.9 or higher, a step of hardening the stock solution with the granules mixed in, and then eluting the granules with the solvent. The present invention is characterized by at least the step of forming pores as removal traces in the portions of the silicone gel body where the particles were present. In addition, the second invention related to the present application, the silicone gel shock absorbing material, is composed of dimethylsiloxane component units,
The following formula

Diorganopolysiloxane (A
component): RR”2S i O-(R2□5in), 5iR1□R
...[11 [However, R is an alkenyl group, R1
is a monovalent hydrocarbon group having no aliphatic unsaturated bonds, and R2 is a monovalent aliphatic hydrocarbon group (at least 50 mol% of R2 is a methyl group, and if it has an alkenyl group, The content is 10 mol% or less),
n is the viscosity of this component at 26°C of 100 to 100.
0OOcSt], the viscosity at 25°C is 5000 cst or less, and the organohydrodiene polysiloxane (component B) has at least three hydrogen atoms directly bonded to Si atoms in one molecule. and the ratio of the total amount of alkenyl groups contained in the diorganopolysiloxane (component A) to the total amount of hydrogen atoms directly bonded to Si atoms in the diorganohydrodiene polysiloxane (component B) ( molar ratio) is 0.
An addition reaction type silicone copolymer is obtained by curing a mixture adjusted to have a solubility of 1 to 2.0 under a platinum catalyst, and the solubility constant Parameter
Particles of a substance that can be dissolved in a solvent with an er) of 9.9 or more are eluted into the solvent after the entire mixture is cured, and are added to the part of the silicone gel body where the particles were present. It is characterized by the formation of pores that are traces of its removal. Effects of the Invention In the present invention, particles mixed into the curing stock solution are removed from the gel-like state, so that voids, which are traces of removal, are formed in areas where the particles were present. These pores improve the buffering and vibration-proofing properties, and if the pores are continuous, air permeability is ensured. On the other hand, the particles have a solubility constant that does not inhibit the curing of the uncured silicone gel solution and does not cause the cured silicone gel to swell and dissolve.
Since the silicone gel is composed of a substance that can be dissolved in a solvent with a value of 9.9 or higher, the solubility parameter
If the silicone gel is immersed in a solvent with a molecular weight of 9.9 or higher, the silicone gel will be eluted without being attacked.

【Example】

Here, the silicone gel which is a constituent element of the present invention is composed of dimethylsiloxane component units, and is a diorganopolysiloxane (component A) used in the following formula [11]: RR'2S i O-(R22S i O) lls
i R1,R...C1] [However, R is an alkenyl group, R1 is a monovalent hydrocarbon group having no aliphatic unsaturated bond, and R2 is a monovalent aliphatic hydrocarbon group (R2 (of which at least 50 mol% is a methyl group, and in the case of alkenyl groups, the content is 10 mol% or less), and n is the viscosity of this component at 25°C of 10
0 to 100.000 cSt],
The viscosity at 25°C is 5000 cst or less, and 1
Organohydrodiene polysiloxanes having hydrogen atoms directly bonded to at least three Si atoms in the molecule (
diorganopolysiloxane (component B) and based on the total amount of hydrogen atoms directly bonded to Si atoms in the organohydrodiene polysiloxane (component B).
This is an addition reaction type silicone copolymer obtained by curing a mixture in which the ratio (molar ratio) of the total amount of alkenyl groups contained in component A> is adjusted to be 0.1 to 2.0. To explain this silicone gel in more detail,
The diorganopolysiloxane, which is the above component A, has a linear molecular structure, and has alkenyl groups R at both ends of the molecule.
is a compound that can form a crosslinked structure by adding with the hydrogen atom directly bonded to the 31 atom in component B. The alkenyl group present at the end of the molecule is preferably a lower alkenyl group, and in consideration of reactivity, a vinyl group is particularly preferred. Furthermore, R1 present at the end of the molecule is a monovalent hydrocarbon group having no aliphatic unsaturated bonds, and specific examples of such groups include methyl, propyl, and hexyl groups. Examples include alkyl groups, phenyl groups and fluoroalkyl groups. In the above formula CI], R2 is a -valent aliphatic hydrocarbon group, and specific examples of such a group include an alkyl group such as a methyl group, a propyl group, and a hexyl group, and a vinyl group. Examples include lower alkenyl groups. However, when at least 60 mol% of R2 is a methyl group and R2 is an alkenyl group,
The amount of the alkenyl group is preferably 10 mol% or less. If the amount of the alkenyl group exceeds 10 mol%, the crosslinking density becomes too high and the viscosity tends to increase. The viscosity at is usually 100 to 100
,0OOcSt, preferably 200-20.000cS
It is set within the range of t. The organohydrodiene polysiloxane, which is the above component B, is a crosslinking agent for component A, and hydrogen atoms directly bonded to Si atoms add to the alkenyl group in component A to harden component A. It is sufficient that the B component has the above-mentioned effect, and the B component can have various molecular structures such as linear, branched chain, cyclic, or network. Also,
In addition to the hydrogen atom, an organic group is bonded to the Si atom in the solar component, and this organic group is usually a lower alkyl group such as a methyl group. Furthermore, the viscosity of component B at 25°C is usually 5000 cst or less, preferably 5
00 cst or less. Examples of such components include organohydrodienesiloxane with both molecular ends capped with triorganosiloxane groups, copolymers of diorganosiloxane and organohydrogensiloxane, tetraorganotetrahydrodienecyclotetrasiloxane, HR ', Si
Copolymerized siloxane consisting of n,... units and 5I04yz units, and HR'2SiO1z2 units and R''g
Copolymerized siloxanes consisting of S r 01/2 units and SiO<z□ units can be mentioned. However, in the above formula, Ht has the same meaning as above. The ratio of the total molar amount of the fulkenyl groups in the A component to the total molar amount of the hydrogen atoms directly bonded to 81 in the B component is usually 0.1 to 2.0, preferably 0. It is manufactured by mixing and curing component A and component B so that the ratio falls within the range of 1 to 1.0. The curing reaction in this case is usually carried out using a catalyst. The catalyst used here is preferably a platinum-based catalyst, and examples of such platinum-based catalysts include finely ground elemental platinum, chloroplatinic acid, platinum oxide, complex salts of platinum and olefins, and platinum alcoholades. and complex salts of chloroplatinic acid and vinylsiloxane. Such a catalyst is usually used in an amount of 0.1 ppm or more (in terms of platinum, the same applies hereinafter), preferably 0.5 ppm or more, based on the total weight of components A and B. There is no particular restriction on the upper limit of the amount of catalyst, but for example, if the catalyst is in liquid form,
Alternatively, if it can be used as a solution, 2
An amount of 0.00 ppm or less is sufficient. Here, compounds such as sulfur, phosphorus, tin compounds and amines are
It is a so-called catalyst poison that inhibits crosslinking and curing because it easily reacts with the above platinum-based catalyst.Specifically, these include sulfur-based compounds such as potassium sulfate, ammonium sulfate, ammonium persulfate, sodium persulfate, and sulfite. Soda, hydrosulfide, sulfates such as hydroxyamine sulfate, sulfur, carbon disulfide, sodium sulfoxylate (Rongalite)
, thioglycolic acid and its derivatives such as thioglycolic acid and butyl thioglycolate, mercaptan compounds such as β-mercaptopropionic acid, thioacetic acid, thiourea,
Examples include surfactants such as sulfonates and sulfuric acid ester salts, and examples of phosphorus compounds include phosphoric acids such as phosphoric acid, ammonium phosphate, phosphorous acid, hypophosphorous acid, sodium pyrophosphate, acidic sodium metaphosphate, and sodium tripolyphosphate. Its salts, trimethyl phosphate, dialkyldithiophosphoric acid, phosphorous acid esters, etc. are listed, and tin compounds include various tin chlorides and tin oxides, as well as rhodan salts, stannous sulfate, etc. Examples of the compound include iminobispropylamine, triethylamine, 3-diethylaminopropylamine, tetramethylethylenediamine, and 3-methoxypropylamine. Then, component A, component B, and catalyst as described above are mixed and cured by standing at room temperature or heating to produce the silicone gel used in the present invention. When curing by heating, the heating temperature is usually 60 to 1
The temperature is 60°C. The silicone gel obtained in this way is JIS
(K-2207-198050g load) The penetration is usually 5 to 250 degrees. The hardness of such a silicone gel can be adjusted by using the amount of the above-mentioned A component in excess of the amount that can form a crosslinked structure with the hydrogen atoms directly bonded to Si in the B component. can. In addition, as another method, silicone oil having methyl groups at both ends is applied to the resulting silicone gel for 5 to 7 hours.
6% by weight 1g! It can also be adjusted by adding the amount in advance. Such a silicone gel can be prepared as described above, or a commercially available silicone gel can be used. Examples of commercially available silicone gels that can be used in the present invention include CF3027 and TOUG. )I-3, TOU
GH-4, TOUGH-6, TOUGH-6 (@III
) - made by Resilicone) and χ32-902/cat 1
300 (manufactured by Shin-Etsu Chemical), F25O-12,1 (
(manufactured by Nippon Unicar), etc. In addition to the above-mentioned component A, component and catalyst, pigments,
Curing retarders, flame retardants, fillers, etc. can be added within the range that does not impair the properties of the resulting silicone gel.
Alternatively, a composite silicone gel containing microscopic hollow spheres may be used. 1 Such materials include Phyllite (registered trademark) manufactured by Nippon Phyllite Co., Ltd., Expancel (registered trade name) sold by the same company, Examples include Matsumoto Microspheres manufactured and sold by Matsumoto Yushi Pharmaceutical Co., Ltd. The particles to be mixed into the uncured solution of the silicone gel should not contain the catalyst poison substance and have a solubility constant (S
consistency parameter) is 9
．． Any granule consisting of a substance that can be dissolved in a solvent of 9 or more is sufficient, and the particle size is not limited, but granules with a particle size of around 0.5 mm are preferred in terms of elution efficiency and finished state. Zero grains that give favorable results have a solubility constant (SolubilityP parameter
r) It is necessary to be able to dissolve in a solvent of 9.9 or higher because even if the particles can be dissolved and eluted, it is meaningless if the silicone gel that is the base material is greatly swollen or eroded. Solubilit
This is because it has been confirmed that if the solvent has a yP parameter of 9.9 or more, even if the cured silicone gel is slightly swollen, the swelling remains within a range that does not cause any practical problems. From the point of view of not swelling or corroding the silicone gel, it is best to use water as a solvent.In this case, it is necessary to use water-soluble granules. Soda, polyvinyl alcohol, methylcellulose, methylcellulose, carboxymethylcellulose, polyethylene oxide, polyvinylpyrrolidone, acrylic acid amide, glue, gelatin, casein,
Examples include granules of polypeptide, funori, agar, sodium alginate, sodium chloride, calcium chloride, glucose, sucrose, natural polysaccharide pullulan, xanthan gum, starch, and sodium ascorbate. On the other hand, the solubility constant other than the amount of water (SolubilityP araw +
Suitable solvents with ether) of 9.9 or higher include:
Examples include acetone, ethanol, methanol, etc., and those that can be dissolved in these include polyvinyl alcohol, methyl cellulose, ethyl cellulose, water-soluble nylon,
Examples include shellac and styrene. In addition, when the granular substance is something like starch, the present invention also contemplates using an enzyme solution in water as a solvent. Examples of these enzymes include amylase, maltase, pepsin, and triazine. , nilepsin, glucose, fructose, etc. Furthermore, it may even be an aqueous solution containing microorganisms that decompose polymers such as starch. Next, as an example of the present invention, using water as a solvent,
An example in which commercially available common salt such as sodium chloride is used as the water-soluble granules will be described below. In the example, sodium chloride particles are mixed into the mixture of the A component, B component, and catalyst of the silicone gel. Therefore, it is better to mix the whole thing again. Furthermore, in order to remove the air taken in during mixing, it is desirable to perform vacuum defoaming before curing. In addition, in the examples, the penetration A silicone gel prepared as in No. 30 was used. Although it is not necessary to specifically explain the table salt, which is a granular form of sodium chloride, it is generally commercially available and has a fairly uniform cubic shape of about 0.4 mm. and the silicone gel stock solution weight ratio is 2
The mixture was divided into A component and B component so as to have a ratio of :1, and the A component and B component were further mixed, poured into a cylindrical mold, and cured in an upright state. Here, the specific gravity of table salt is about 2, and the specific gravity of silicone gel is about 1.
Therefore, the common salt is deposited from the bottom of the silicone gel undiluted solution on the curing bolt as if it were settling naturally, and the silicone gel undiluted solution fills around each salt. The gel will harden. Therefore, for example, if the product is left at 80° C. for 1 hour, the A component and the component will react, and a silicone gel in which salt is dispersed and hardened into a round rod shape will be obtained in the mold. In addition, the weight ratio of the weight of the salt to the silicone gel stock solution is 2.
= 1, and if the amount of silicone gel undiluted solution is larger, a layer consisting only of silicone gel is formed on a part of the surface layer. When the ratio is about 2:1 as in the example, a layer consisting only of silicone gel is not formed on the surface layer, and the entire layer becomes a layer of silicone gel in which salt is dispersed. Conversely, when the amount of salt increases, it becomes difficult to mix it with the silicone gel stock solution and vacuum defoaming, and at the same time, the number of pores occupied by the salt increases, resulting in a thinner network structure in the finished state. will be obtained. In practice, the weight ratio of the salt to the silicone gel stock solution is preferably 1.6:1 to 4:1, preferably about 2:1. Next, the cured silicone gel with the salt dispersed therein is taken out of the mold, and in the example, it is sliced into pieces of appropriate thickness, for example, 10 mm 41 iF, and then placed in a boiling water tank and heated several times with hot water. After repeating the boiling process several times, draining the hot water and drying it, pores were formed as traces of removal in the silicone gel body where the salt had been present, and the silicone gel became open-celled. A disc-shaped sheet of porous silicone gel was obtained. The pores in the resulting sheet are in a state where adjacent pores are continuous, making it look like a silicone gel sheet that has been continuously foamed from the inside, and has excellent breathability, cushioning properties, and anti-vibration properties. The characteristics were good. Because of the relationship between the specific gravity of the salt and the silicone gel stock solution, a stable porous body with open cells can be obtained at all times, making it extremely excellent as a shock-absorbing material for light loads. Ta. Since sodium chloride was used in the form of granules and dissolved in hot water, it did not react with the silicone gel stock solution, did not inhibit the catalytic action of the platinum catalyst, and did not adversely affect the cured silicone gel. , can be created at low cost. In addition, suitable examples of using water as a solvent include combinations with granules of calcium chloride, and combinations with granules of sugars such as simitose. Next, using styrofoam ball-shaped particles as particles, the solubility constant (Solubility Par
Another example in which acetone is used as a solvent with a value of 9.9 or more will be described. In this example, commercially available styrofoam balls with a diameter of about 3 mm were used, and the styrofoam balls were mixed into the gel stock solution A component and B component so that the volume ratio to the silicone gel stock solution was 2:a. Furthermore, component A and component A were mixed and poured onto a glass plate with 10 mm thick spacers on each side, a glass plate was placed over the top, and this was placed in a processing furnace maintained at 80°C. The mixture was left to stand for 30 minutes to obtain a silicone gel sheet with a thickness of 10 mm. If the mixing ratio of the Styrofoam balls is low at this time, the Styrofoam balls will float in the silicone gel stock solution due to their specific gravity, resulting in a state where they are unevenly distributed on the upper layer of the silicone gel sheet.
If the amount is too large, it will be dispersed almost throughout the space so as to fill the spaces between the styrofoam. Next, when this silicone gel sheet was immersed in a vat filled with acetone, which is a solvent for styrofoam, and left for about 3 hours, the silicone gel swelled very slightly, but it was not a problem for practical use, and the styrofoam ball swelled slightly. was gradually dissolved in acetone, and eventually voids, which were traces of removal, were formed in the silicone gel sheet where the particles had been present. In this example, when the foamed polystyrene balls are unevenly distributed and hardened, the pores are continuous with adjacent pores in the upper layer of the silicone gel sheet, resulting in a state that looks like continuous foaming. In the lower layer, a layer consisting only of silicone gel is formed. Thereafter, the partially absorbed acetone was sufficiently volatilized by infrared rays, etc., to obtain a porous silicone gel shock absorbing material. In addition, when a layer of only silicone gel is formed unevenly in this way, as in the case of the above example,
It can be used as a silicone gel cushioning and vibration damping material with a multi-layer structure in which holes are present only on the side that comes into contact with the human body, and the other layer is made of ordinary silicone gel. Further, preferred examples of using ethyl alcohol or methyl alcohol as a solvent include combinations with water-soluble nylon granules, combinations with ethyl cellulose granules, combinations with shellac granules, etc. . As mentioned above, this type of silicone gel cushioning and vibration isolating material is made from silicone gel, so the material itself is stable, and it has better cushioning and vibration isolation properties than conventional silicone gel, even under light loads. It has become excellent as a shock absorbing and vibration-proofing material for cars, and if the holes are continuous, it also ensures ventilation, so it can be used for seat sheets, helmets, headrests, and even interior pond materials. It is suitable as a material for shoe soles, pine tresses, etc. (Effects of the Invention) Therefore, according to the present invention, foaming of silicone gel, which has been considered difficult in the past, can be achieved by removing the granules mixed in the pre-curing stock solution from the gel-like state, and This is achieved by forming pores as removal traces in the area where the body was present, and the pores improve the cushioning and vibration damping properties without losing the body as a silicone gel, and the pores are continuous. If it is, a silicone gel cushioning and vibration isolating material with ensured air permeability can be obtained. Therefore, it has become suitable as a material for parts that come into direct contact with the human body, such as seat sheet materials and helmet interior materials.
Further applications such as cushioning, anti-vibration, and material for seed rice are expected.
A1* I can do it.

Claims (2)

[Claims] (1) The solubility constant (Solu
a step of mixing particles of a substance that can be dissolved in a solvent with a property parameter) of 9.9 or more, a step of hardening the stock solution mixed with the particles, and then a step of eluting the particles with the solvent. A method for manufacturing a silicone gel cushioning and vibration isolating material, which comprises at least the step of forming pores, which are traces of removal, in a region of the silicone gel body where the particles were present. (2) Consists of dimethylsiloxane component units, and is composed of the following formula [
Diorganopolysiloxane (component A) used in I]
: ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [I] [However, R is an alkenyl group, R^1 is a monovalent hydrocarbon group having no aliphatic unsaturated bond, and R^ 2 is a monovalent aliphatic hydrocarbon group (at least 50 of R^2
mol% is a methyl group, and if it has an alkenyl group, its content is 10 mol% or less), and n is the viscosity of this component at 25°C of 100 to 100,000.
cSt], the viscosity at 25°C is 5000 cSt or less, and at least 3 cSt in one molecule.
organohydrodiene polysiloxane (component B) having a hydrogen atom directly bonded to six Si atoms,
and the ratio (mole ratio) of the total amount of alkenyl groups contained in the diorganopolysiloxane (component A) to the total amount of hydrogen atoms directly bonded to Si atoms in the diorganohydrodiene polysiloxane (component B). is 0.1-2.
This is an addition reaction type silicone copolymer obtained by curing a mixture adjusted to have a solubility constant (S
Particles of a substance soluble in a solvent with an olu-bility Parameter) of 9.9 or more were eluted into the solvent after the entire mixture was cured, and the particles were present in the silicone gel body. A silicone gel cushioning and vibration isolating material characterized by having holes formed therein as traces of its removal.