JPS62263256A - Curable polyorganosiloxane composition - Google Patents

Abstract

PURPOSE:The titled composition useful as a constituent material for a parent mold for templating useful in molding of FRP, obtained by blending a liquid polyorganosiloxane with a specific amount of hollow fine particles of silicate glass having specific particle diameter. CONSTITUTION:A composition consisting of (A) 100pts.wt. polyorganosiloxane containing two or more units shown by formula I(R<1> is alkenyl; R<2> is monofunctional hydrocarbon group containing no aliphatic unsaturated bond; a is 1 or 2; b is 0-2; a+b is 1-3), (B) a polyorganohydrogene siloxane which contains a unit shown by formula II(R<3> is monofunctional hydrocarbon group; c is 0-2; d is 1 or 2; c+d is 1-3) and 3 hydrogens bonded to Si in an amount to give 0.5-4 hydrogens bonded to Si based on R<1> of the formula I, (C) 1-100ppm calculated as Pt based on the component A of a platinum catalyst, (D) 0.1-20pts.wt. hollow fine particles of silicate glass having 60-100mum average particle diameter and (E) 0.1-300pts.wt. inorganic filler.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to 1 called fiber reinforced plastic (FRP).
Among the group of composite materials, curable polyorganosiloxane is particularly suitable as a constituent material of a mold for molding used when molding a composite material containing carbon mm or glass fiber and having an epoxy resin as a matrix. Regarding the composition.

[Technical background of the invention and its problems] FRP is widely used in various fields because of its excellent properties such as mechanical strength. Among these FRPs, those that have an epoxy resin as a matrix, such as carbon 18 m/epoxy resin composite material (CF R
P) and glass fiber m/epoxy resin composite materials are known, and CFRP in particular is used as a component material for space development-related parts, aircraft parts, etc. because of its high specific strength and specific rigidity. When molding a composite material using such an epoxy resin as a matrix into a desired shape,
For example, use the following method. That is, a laminate obtained by laminating a desired number of prepregs obtained from a composite material having an epoxy resin as a matrix is placed in a mother mold made of silicone rubber.Next, the laminate is placed in an autoclave at a temperature of about 120 to 200°C. Approximately 5-7 kgf/
cm2f) A molded body can be obtained by curing the epoxy resin while applying pressure. Note that prepreg here refers to, for example, CFRP as a bundle of fibers (
After making a tow shape, plain weave, satin weave, three-dimensional weave, etc., the solvent used at that time was removed by leaving it in a semi-dry state, and then it was sandwiched between release paper to create a typical It is a name.

As a matrix used in such a molding method, one whose constituent material is a curable polyorganosiloxane composition has conventionally been used. In particular, liquid polyorganosiloxane compositions are excellent in workability because they are easy to mold because they are liquid before curing, and they can be easily hardened by heating.

In addition, a matrix made of the composition has excellent heat resistance.

It is suitable as a matrix material because it has chemical resistance and moldability, and because the shrinkage rate of the cured product due to temperature changes is extremely small, molds with high dimensional accuracy can be obtained.

However, when the matrix obtained from such a polyorganosiloxane composition is used repeatedly, the mold releasability decreases, resulting in an adhesion phenomenon between the molded body and the matrix. . Furthermore, the pressure and temperature applied during molding may cause the matrix to become brittle. Such problems are particularly noticeable when a composite material having an epoxy resin as a matrix is used as a molding material. For example, when CFRP is used as the molding material, the CFRP and the mother die will adhere even after several molding operations, making it impossible to continue the molding operation. This is thought to be caused by the action of the epoxy resin, oligomers, and curing catalysts that constitute the resin, which are produced by decomposition of the epoxy resin.

As a method to solve these problems, silicone oil whose molecular chain ends are blocked with triorganosilyl groups is blended into the composition or applied to the area where the mold comes into contact with the molding material. There is a known method for improving mold releasability.

However, in the case of a method of blending silicone oil into a polyorganosiloxane composition.

Under the above-mentioned curing conditions, the silicone oil blended during curing suddenly oozes out onto the rubber surface, and furthermore, the oozed silicone oil evaporates out of the system. As a result, femininity rapidly declines,
For this reason, it is not possible to improve the life of the mold, and the silicone oil that has oozed out from the rubber surface adheres to the molding material or penetrates into the material during the curing process. This will significantly reduce the physical properties of the mold, making it difficult to perform subsequent processing such as painting, resulting in a defective product.Also, applying silicone oil to the parts where the mold comes into contact with the molding material. In the case of this method, the application work is extremely complicated,
It cannot be said that it is an industrial method.

In this way, FRP with epoxy resin as a matrix
When a matrix obtained from a polyorganosiloxane composition is used for molding, there is a strong desire for fundamental improvement of the composition in order to improve its mold releasability and durability.

[Object of the Invention] The present inventors have solved the above-mentioned problems, and have provided a method for molding an FRP composite material having an epoxy resin as a matrix using a matrix made of silicone rubber, in which the mold release from the composite material of the matrix is improved. The purpose of the present invention is to provide a curable polyorganosiloxane composition useful as a constituent material of a matrix, which can greatly increase the number of moldings by improving its properties and durability.

[Structure of the Invention] As a result of intensive research aimed at solving the above problems, the present inventors added a predetermined amount of silicate having a specific particle size to liquid polyorganosiloxane, which is a rubber component. By using a composition containing glassy hollow microparticles, in the method of molding FRP with an epoxy resin as a matrix, the female moldability and durability are extremely excellent, and the number of molding operations can be significantly increased. It was discovered that a matrix for making molds could be obtained.

The present invention has now been completed.

That is, the curable polyorganosiloxane composition of the present invention has the following formula: (A) (R") (R2) S i Oo (I) a
b (wherein R1 represents an alkenyl group, R2 represents a substituted or unsubstituted monovalent hydrocarbon group containing no aliphatic unsaturated bond; a represents 1 or 2; b is 0.1 or 2 represents; a+b is l.

100 parts by weight of a polyorganosiloxane having at least two structural units represented by the formula (2 or 3) in one molecule; (B) the following formula;

(R3) cHd"io ool (lIl) (wherein,
R3 represents a substituted or unsubstituted monovalent hydrocarbon group; C
represents 0, 1 or 2; d represents 1 or 2; c
+d represents 1.2 or 3) A polyorganohydrodiene siloxane having at least three hydrogen atoms bonded to a silicon atom in one molecule is prepared by formula (I) of the component (A). ) in an amount such that the number of hydrogen atoms bonded to silicon atoms is 0.5 to 4.0 per R11 in the structural unit represented by (C) component (A) using a platinum-based catalyst as a platinum atom. 1 to 1100 pp per polyorganosiloxane; (D) 0.1 to 20 parts by weight of silicate glass hollow microparticles with an average particle size of 60 to 100 μ; and (E) Inorganic filler, 0 .1 to 300 parts by weight;

The polyorganosiloxane as component (A) used in the present invention has at least two structural units represented by formula (I) containing an alkenyl group bonded to a silicon atom in one molecule. As such polyorganosiloxane, either linear or branched polyorganosiloxane can be used, and a mixture thereof can also be used.

Examples of R1 in the above formula include vinyl group, allyl group, l-butenyl group, l-hexenyl group, etc., but vinyl group is the most advantageous in terms of ease of synthesis and thermal stability. l(2 and R1 and R2
In addition, examples of organic groups that can bond to silicon atoms include alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, and dodecyl; aryl groups such as phenyl; β-phenylethyl; Examples include aralkyl groups such as β-phenylpropyl, and further examples include substituted hydrocarbon groups such as chloromethyl and 3,3,3-trifluoropropyl. Among these groups, the methyl group is preferred as the group R2 because it is easy to synthesize, provides the degree of polymerization necessary to maintain good physical properties after curing, and provides low viscosity before curing. Most preferred and compositions of the invention are:
It is used as a matrix material for mold making, and therefore, it has properties suitable for this, in particular, appropriate flowability before curing, and excellent physical properties after curing. Therefore, the viscosity at 25°C is 50 to 200,000 cP, especially 100 to 10
Viscosity is 50 cP, preferably 0.000 cP
If it is not grooved, it will be difficult to obtain sufficient elongation and elasticity after curing, and if the viscosity exceeds 200,000 cP, workability in casting and other operations will be poor.

Component (B) used in the present invention is polyorganohydrodiene siloxane, which must have at least three silicon-bonded hydrogen atoms in one molecule in order to form a network through crosslinking. It is. Examples of R3 in the above formula and other organic groups capable of bonding to a silicon atom include those similar to R2 in the component (A), but from the viewpoint of ease of synthesis, a methyl group is preferred. Most preferably, such polyorganohydrogensiloxanthosites are linear,
Either branched or cyclic forms can be used, and mixtures thereof can also be used.

The blending amount of component CB) is 1 fluorenyl group in component (A).
, the number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5 to 4.0, preferably 1.0 to 3.0.
The amount is such that If the number of hydrogen atoms is less than 0.5, curing of the composition will not proceed sufficiently and the hardness of the cured composition will be low; if the number of hydrogen atoms exceeds 4.0, The physical properties of the composition after curing are reduced.

The platinum-based catalyst as component (C) used in the present invention is (A)
This is a component that promotes the addition reaction between the alkenyl group in the component and the hydrosilyl group in the component (B). Examples of such platinum-based catalysts include simple platinum, chloroplatinic acid, platinum coordination compounds such as platinum-olefin complexes, and platinum-alcohol complexes.

The blending amount of component (C) is 1 to 1100 pp, preferably 2 to 50 pp as platinum atoms, relative to component (A).
It is m. If the amount is less than i ppm, the object of the present invention cannot be achieved, and even if it exceeds 100 ppm, no further improvement in the curing rate can be achieved.

The silicate glassy hollow microparticles of component (D) used in the present invention are the main constituent material of the matrix when molding, for example, FRP with an epoxy resin matrix (
It is a component that improves the mold releasability between component A) and the FRP molded body. This component (D) is made of silicate glass, and the inside of the microparticle is hollow. Although the shape is not particularly limited, it is preferable that it be spherical in order to achieve the object of the present invention.Silicate glasses that can be used as constituent materials of such microparticles include, for example, borosilicate glass, Examples include lead glass and soda-lime glass, which have excellent heat resistance, chemical durability,
Borosilicate glass is most preferred from the viewpoint of water resistance, acid resistance, low coefficient of thermal expansion, etc. Natural glass can also be used as such silicate glass.

Such component (D) has an average particle diameter of 60 to 10
0-, preferably 60 to 85 units. If the average particle diameter is less than 60 units, sufficient mold releasability cannot be imparted to the matrix, and if it exceeds 1 oou, the mechanical strength of the matrix is significantly reduced.

The blending amount of component CD) is 0.1 to 20 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of component (A). If the amount is less than 0.1 parts by weight, the object of the present invention cannot be achieved, and if the amount exceeds 20 parts by weight, no improvement in mold releasability can be expected. Moreover, the mechanical strength of the matrix also decreases.

The inorganic filler as component (E) used in the present invention is as follows.

It makes the viscosity and fluidity of the composition appropriate and gives the cured product excellent mechanical strength, hardness, thermal conductivity, etc., and also has the effect of assisting the addition effect of component CD). It shows. Examples of such inorganic fillers include fumed silica, precipitated silica, fused silica, fine quartz powder, diatomaceous earth, alumina, aluminum silicate,
Examples include iron oxide, titanium oxide, zinc oxide, calcium carbonate, and carbon black, and one or more of these can be used. In addition, these inorganic fillers can be coated with polyorganosiloxanes such as polydimethylsiloxane and octamethylcyclotetrasiloxane; hexamethyldisilazane and 1,1,3
．． Those coated with organosilicon compounds such as silazane such as 3-tetramethyl-1,3-divinyldisilazane; and organosilanes such as vinyltriethoxysilane can be used.

The blending amount of component (E) is 0.1 to 300 parts by weight, preferably 5 to 200 parts by weight, per 100 parts by weight of component (A). If the amount is less than 0.1 part by weight, the mechanical strength, hardness and thermal conductivity of the cured product will be poor, and the
If it exceeds 0 parts by weight, the fluidity of the composition will deteriorate and the cured product will become brittle.
If the desired degree of effect can be obtained by adding component (D), it does not necessarily have to be added.

The composition of the present invention can be produced by uniformly mixing the components (A) to (E) described above.

[Examples of the Invention] Hereinafter, the present invention will be further described in detail with reference to Examples and Comparative Examples. In addition, all "parts" in Examples and Comparative Examples represent "parts by weight."

Example 1 100 parts of polydimethylsiloxane (base oil) having a viscosity of 5,000 cP at 25°C and having both ends of its molecular chain blocked with dimethylvinylsilyl groups.

Ioo part of Ishifu fine powder, consisting of (CH3)2 H3iO'A units and 5i02 units, contains 1.02fi mass% of hydrogen atoms bonded to silicon atoms, and has a viscosity of 21% at 25°C.
cP polydimethylhydrodiene siloxane 2 parts, 4
0.2 parts of isopropyl alcohol solution of chloroplatinic acid (
) and 4 parts of Q-CEL 200 (manufactured by Asahi Glass Co., Ltd., trade name), which is a hollow spherical microparticle based on sodium borosilicate and has an average particle size of 75, are mixed uniformly. be dispersed into
A mother mold made of silicone rubber was produced by curing at 100''C for 1 hour.

Next, using the matrix obtained above, a laminate obtained by laminating Torayca Cloth (manufactured by Toshi Co., Ltd., trade name), which is a prepreg made of carbon fiber/epoxy resin, was placed in the matrix, and autoclaved. It was cured at 170"C for 60 minutes. A molding test was conducted by repeating this procedure to determine the number of times a good molded product could be obtained. As a result, a good molded product could be obtained up to 25 times. It was done.

Example 2 The matrix obtained in Example 1 was used, except that prepreg TLP 551 (manufactured by Toshiba Chemical Corporation, trade name) consisting of glass mm/epoxy resin was used instead of carbon MIi fiber/epoxy resin prepreg. A molding test was conducted in the same manner. As a result, good molded products could be obtained up to 31 times.

Comparative Example 1 A matrix was obtained in the same manner as in Example 1 except that Q-CEL 200 was not used, and trading card cloth and T
A molding test of LP 551 was conducted. As a result, no matter which prepreg was used, the composite molded product and the silicone rubber matrix adhered to each other at the second time, making subsequent molding impossible.

Comparative Example 2 In the same manner as in Example 1, except that instead of using Q-CEL 200, 10 parts of dimethylpolysiloxane having a viscosity of 100 cP at 25°C and whose molecular chains were blocked at both ends with trimethylsilyl groups was added. Obtain the matrix,
We investigated the number of molds of trading card cloth. As a result, the composite molded body and silicone rubber matrix adhered to each other after the fifth try.
Further molding was no longer possible.

Example 3 100 parts of polydimethylsiloxane base oil with a viscosity of 20,000 cP at 25°C, both ends of the molecular chain capped with dimethylvinylsilyl groups, Aerosil 200 (trade name, manufactured by Nippon Aerosil Co., Ltd.) which is fumed silica 2
0 parts, 1.5 parts of a linear polymethylhydrodiene siloxane whose molecular chain ends are capped with trimethylsilyl groups, contains 0.8% by weight of hydrogen atoms bonded to silicon atoms, and has a viscosity of 20 cP at 25°C. , 2% by weight of platinum atoms
0.1 part of octatool solution of platinum chloride octene complex (20 ppm as platinum based on base oil) and 2 parts of 3M Glass Bubbles A 161500 (manufactured by 3M Co., Ltd., trade name), silicate vitreous hollow spherical microparticles, were mixed. The mixture was uniformly dispersed and cured at room temperature to produce a rubber sheet measuring 2 x 300 x 300 mm.

Next, 5 sheets of square trading card cloth with a side of 250 mm were stacked and sandwiched between the two rubber sheets manufactured in this way, and the press pressure was 20 kgf/c + s2° and the temperature was 17°.
Curing was performed at 0° C. for 1 hour, and a test was conducted to see how many times a good molded product could be continuously obtained from the same rubber sheet.

As a result, the number of times of molding was 15. In addition, 15
When the strength of the composite molded product obtained for the fifth time was measured, the tensile strength was 72 kgf/am" and the bending strength was 84 kgf.
/am2, and the physical properties were almost the same as those obtained when curing using a mold. In addition, the tensile strength and elongation of the silicone rubber sheet after repeated molding 15 times were measured and compared with the values before the test, and as a result, the retention rate was maintained at 70% or more in all cases.

Comparative Example 3 A matrix was obtained in the same manner as in Example 3 except that 3M Glass Bubbles was not used, and the number of times the carbon fiber/epoxy resin composite material was molded was tested. An adhesion phenomenon was observed.

Comparative Example 4 Using the matrix obtained in Comparative Example 3, for the purpose of improving the mold releasability of this matrix and the carbon fiber/epoxy resin composite molded product,
Polydimethylsiloxane, which has a viscosity of 500 cP at 25°C and whose molecular chain ends are capped with trimethylsilyl groups, was applied to the silicone rubber surface in contact with the molded body using a brush every time press molding was performed, but everything else was carried out in the same manner. The number of moldings was tested. As a result, an adhesion phenomenon was observed after the 8th test. In addition, the strength of the carbon fiber/epoxy resin composite obtained in the 8th time was that the tensile strength was 54 kgf/sm2° and the bending strength was 62 kgf/m2, which was due to the transfer of the applied polydimethylsiloxane to the molded body. Deterioration of characteristics was observed.

Comparative Example 5 A matrix was prepared in the same manner as in Example 3, except that instead of using 3M Glass Bubbles, 30 parts of polydimethylsiloxane, which had a viscosity of 50 cP at 25°C and whose molecular chain terminals were blocked with trimethylsilyl groups, was used. Gain,
Further, when testing the number of times of molding, an adhesion phenomenon was observed at the fifth time.

Furthermore, the tensile strength of the carbon fiber/epoxy resin composite obtained at the fifth time was 68 kgf/mm2. The bending strength was 69 kgf/mm2, and there was a deterioration in the properties due to the transfer of polydimethylsiloxane contained in the matrix to the molded product.

Example 4 In Example 3, the base oil had a viscosity of 3,000 cP at 25°C, both ends of the molecular chain were blocked with dimethylvinylsiloxy groups, and the composition ratio of dimethylsiloxane units to diphenylsiloxane units was 95:5. 100 parts of polymethylphenylsiloxane and 2 parts of polydimethylhydrodienesiloxane used in Example 1.
A mother mold was obtained in the same manner except that a mold was used, and as a result of testing the number of moldings, no adhesion phenomenon was observed until the 13th molding, and a good molded product could be obtained.

Comparative Example 6 A matrix was obtained in the same manner as in Example 4 except that 3M Glass Bubbles was not used, and when the number of moldings was tested, an adhesion phenomenon was observed from the first time, and subsequent molding was impossible. Ta.

[Effects of the Invention] As explained above, the curable polyorganosiloxane composition of the present invention, when used as a constituent material of a mold for molding used in the molding of FRP having an epoxy resin as a matrix, The mold has excellent durability even under severe curing conditions such as high temperature and high pressure during molding, and exhibits excellent mold releasability for FRP molded bodies. Therefore, by using such a matrix, the number of times FRP is molded using the same matrix can be dramatically increased. Therefore, the production cost of FRP molded bodies can be significantly reduced.

The matrix obtained from the composition of the present invention exhibits particularly excellent effects in a method of molding using end layer bodies obtained by laminating a desired number of prepregs made of FRP with an epoxy resin matrix. can do.

Claims (5)

[Claims] (1) (A) The following formula, (R^1)_a(R^2)_bSiO_[_4_-_(
_a_+_b_)_]_/_2(I) (in the formula, R^1
represents an alkenyl group; R^2 represents a substituted or unsubstituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond; a
represents 1 or 2; b represents 0, 1 or 2; a+
b represents 1, 2 or 3) 100 parts by weight of a polyorganosiloxane having at least two structural units in one molecule;
_d_)_]_/_2(II) (wherein, R^3 represents a substituted or unsubstituted monovalent hydrocarbon group; c represents 0, 1 or 2; d represents 1 or 2; c+d represents 1, 2 or 3) and has at least 3 hydrogen atoms bonded to a silicon atom in one molecule. An amount such that the number of hydrogen atoms bonded to silicon atoms is 0.5 to 4.0 with respect to R^11 in the structural unit represented by; (C) platinum-based catalyst as platinum atoms (A) 1 to 100 ppm based on the component polyorganosiloxane; (D) 0.1 to 20 parts by weight of silicate glass hollow microparticles having an average particle size of 60 to 100 μm; and (E) an inorganic filler; 0.1 to 300 parts by weight of a curable polyorganosiloxane composition. (2) The curable polyorganosiloxane composition according to claim 1, wherein the polyorganosiloxane component (A) has a viscosity of 100 to 100,000 cP at 25°C. (3) The curable polyorganosiloxane composition according to claim 1, wherein the amount of component (D) is 0.5 to 5 parts by weight. (4) The curable polyorganosiloxane composition according to claim 1, wherein the silicate glass of component (D) is borosilicate glass. (5) The curable polyorganosiloxane composition according to claim 1, wherein the amount of component (E) is 5 to 200 parts by weight.