JP3312979B2 - Prepreg, method for producing prepreg, cured prepreg, fired prepreg, method for manufacturing fired prepreg, method for densifying fired prepreg - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a prepreg, a method for producing a prepreg, a cured prepreg, a prepreg fired body, a method for producing a prepreg fired body, and a method for densifying a prepreg fired body.

[0002]

2. Description of the Related Art Ceramics have the advantage of being superior in heat resistance, high-temperature strength, oxidation resistance, abrasion resistance and the like as compared with organic materials or metal materials, but have the disadvantage of low fracture toughness. Without losing the strength of ceramics
As a method for improving fracture toughness, that is, toughening, a particle dispersion method, a whisker or short fiber reinforcement method, a long fiber reinforcement method, and the like have been studied.

[0003] However, the particle dispersion method and the whisker strengthening method have a drawback that even if the toughness can be improved, if a very small portion of the material is broken, the whole of the material is broken all at once.

[0004] On the other hand, the reinforcing method using long fibers has a greater effect of improving the fracture toughness than other methods. In addition, in the case of long fiber reinforced ceramics, the fibers bear the load even when a load is applied. The destruction does not progress at once, and you can predict the destruction before it is completely destroyed. This predictability of failure is a great advantage in practical use.

However, when the reinforcing method using long fibers is adopted, long fibers which maintain sufficient strength even at a temperature of 1,200 ° C. or more in air and 1,400 ° C. or more in an inert atmosphere are not yet practical. And therefore,
It has been desired to develop a method capable of producing a composite at 1,200 ° C. or lower, preferably 1,000 ° C. or lower.

Producing the composite at a low temperature in this way can naturally be expected to greatly reduce the cost. Further, in order to produce a product having a curved shape or a complicated shape, a method of laminating and molding a prepreg having good tackiness and drapability as used in production of a carbon fiber / epoxy composite or the like. Is desirable. Furthermore, for industrial production, the firing operation can be carried out in the air without replacing the atmosphere with an inert atmosphere or vacuum, and the molded body is free standing, that is, under unconstrained conditions. Of course, it is advantageous to be able to sinter.

Chemical vapor deposition and direct metal oxidation are known as methods for producing fiber reinforced ceramics by directly forming a ceramic matrix between fibers. These methods can be applied not only to long fiber bundles and products thereof, but also to aggregates of short fibers or whiskers.

[0008] The chemical vapor deposition method is a method of depositing and depositing a ceramic as a matrix in a bundle of fibers or a gap between preforms by chemical vapor deposition (CVI) (for example, J. Amer.
T. Hoyt et al., SAMPE J. 27 No. 2, P11 (1991)). This method has a relatively low temperature, for example, from 1,000 to
Although there is an advantage that a ceramic matrix is formed at 1,200 ° C., it takes a long time, for example, 100 hours, to form the ceramic matrix, and the rate of void generation (void rate) is high, and it is difficult to cope with complicated shapes. There's a problem.

The metal oxidization (Directed Metal Oxidation) method is a method in which a molten metal is brought into contact with a preform of a reinforcing fiber, and the metal is converted into ceramics by oxidation and nitridation. This method is described, for example, in MS Newkirk et al., J. Mat.
er. Sci., are described, for example, 1 81 (1986). Although this method has an advantage that various ceramic matrices can be formed by changing the metal and the heating atmosphere, the metal remains in the product, and thus the strength tends to decrease at high temperatures. Also in this method, there is a great limitation in manufacturing a product having a complicated shape.

Using a prepreg traditionally employed in the composite material industry, the prepreg is laminated, formed into a predetermined shape into a product shape, and then fired to convert a matrix component into a ceramic body. Known methods for producing reinforced ceramics include a slurry impregnation method, a sol-gel method, and a polymer pyrolysis method.

The slurry impregnation method is a method in which a prepreg is prepared by impregnating a fiber with a slurry liquid containing ceramic fine particles and a binder such as an organic polymer, and after removing the binder, hot pressing is performed in an inert atmosphere. This method is described, for example, in CA Doughan et al., Ceram. Eng. Sci. Pro.
c., 10 912 (1989). According to this method, there is an advantage that a fiber-reinforced ceramic product having excellent mechanical properties can be produced.
High temperature of 100-1,800 ° C and 100-350k
It requires a high pressure of g / cm ² , and deterioration of reinforcing fibers other than carbon fibers cannot be avoided. In addition, organic substances are carbonized during binder removal and volatilized and / or thermally shrunk, thereby deteriorating matrix performance and causing cracks and voids.

In this method, water that is inexpensive and easy to remove because of its low boiling point is used as a medium in many cases. However, water is strong against ceramic raw materials such as metal oxides. There is the problem that it has a tendency to adsorb, so that this adsorbed water is not easily removed by heating. This prepreg does not have tackiness.

In the sol-gel method, generally, a metal alkoxide as a liquid raw material is prepared by reacting a metal alkoxide in the presence of an acid or an alkali.
This is a method of converting a sol state to a gel state by hydrolysis and condensation, and further applying heat to form a ceramic. In this method, it is possible to ceramicize even at a low temperature of 1,000 ° C. or less.

However, disadvantages of this method are the large volume shrinkage when converting the wet gel to the dry gel and the occurrence of voids, cracks and fractures due to shrinkage during firing. That is, in some cases, the volume shrinkage is as large as several tens of percent, so that a crack is generated between the fiber and the non-shrinkage fiber (see Japanese Patent Application Laid-Open No. 63-282131).

The polymer pyrolysis method uses an organometallic polymer such as polycarbosilane or polysilazane as a matrix precursor, impregnates it into a fiber to form a prepreg, laminates, cures, and fires. This is a method of converting to a ceramic matrix. This method has been published for example Kiyoto Okamura, such as in Japan composite material Journal 11 99 (1985). Although this method has an advantage that it can be converted to ceramics even at a temperature of 1200 ° C. or less, considerable shrinkage still occurs when the organometallic polymer is converted into a ceramic composition by thermal decomposition. In addition, these organometallic polymers cannot impart necessary tackiness, and have a problem in shapeability.

The following publications and inventions are disclosed as examples of the production of long fiber reinforced ceramics using the above three methods.

M. Chen and colleagues mainly use Boemite (Boemite).
) And 0.5 μm diameter alumina powder were impregnated into carbon fiber or silicon carbide fiber, dried at 50 ° C. for 20 hours, heated to 1,000 ° C. under a nitrogen atmosphere, and then heated. Then, the mixture was cooled and hot-pressed at 1,200 ° C. using a graphite die to prepare a fiber-reinforced ceramic. It has been concluded that the composites obtained in this way are porous, due to the large shrinkage during heating and sintering (ECCM-3 Proceedings, p89 20-2).
3 March (1989)).

FI Hurwitz et al. Prepared a prepreg by a filament winding method using polysilsesquioxane as a matrix precursor and silicon carbide fibers as reinforcing fibers. This prepreg was stacked in a metal die, and the obtained laminate was kept at 70 ° C. and 689 Pa for 2 hours, and further heated to 180 ° C. and kept at 1.5 ° C. for 1.5 hours. The laminate was taken out of the die and subjected to a flow of 525 under an argon stream.
Heated to 1000C, 1000C or 1200C. They found that the heat shrinkage during this heating was 19% for polyvinyl (50) methyl (50) silsesquioxane and 13% for polyphenyl (50) methyl (50) silsesquioxane.
And many cracks are observed on the matrix surface and the inter-fiber matrix region (Ceram. Eng. Sci.
Proc., 10750 (1989)).

Frank Kang Chi et al. Prepared a prepreg by impregnating a high modulus fiber with a thermosetting organosilicone resin dissolved in an organic solvent, and partially cured the prepreg at a temperature not higher than 300 ° C. B-Staging), hardening, post-hardening, and then firing at a temperature of at least 1,000 ° C. in an inert atmosphere or under vacuum (Japanese Patent Publication No. Sho 63). -16350).

They also impregnate high modulus fibers with a mixture of an organic silsesquioxane sol and a colloidal metal oxide or a mixture thereof, or an organic silsesquioxane sol and a metal alkoxide or a mixture thereof. And a fiber-reinforced ceramic is manufactured from the prepreg using the same curing and firing operations and heating atmosphere as described above (see Japanese Patent Publication No. 3-77138).

Although their method appears at first glance to be similar to carbon fiber / epoxy prepregs, the prepregs do not have effective tackiness and are therefore not suitable for producing curved or complex shaped products. Handling is difficult, and peeling between layers tends to occur. Also, since the flow is large, it can not be handled unless it is partially cured, and it requires three stages of curing operations including post-curing until complete curing, so it takes time and effort to manufacture Is a disadvantage. In addition, limiting the firing atmosphere to an inert atmosphere or vacuum obviously results in manufacturing constraints and cost increases.

HAN, Jong, Hoon discloses a tacky and drapable ceramic binder composition. The composition comprises a polymer such as polymethyl methacrylate, a monomer such as trimethylolpropane trimethacrylate, a peroxide such as dicumyl peroxide and a solvent such as acetone. They composited inorganic fibers such as alumina fibers with a slurry liquid obtained by mixing the binder composition and a ceramic component such as alumina, and then further cured at 149 to 170 ° C, and then cured at a temperature of 480 ° C or less. A method for producing a fiber-reinforced ceramic in which the binder is removed by firing and the ceramic component is further sintered at 500 to 2,500 ° C. is disclosed (see WO92 / 22509).

This method employs a cross-linking agent / co-crosslinking agent system commonly used in the industry for vulcanization of rubber or cross-linking of organic polymers (Takuma Matsumoto, "Vulcanization and co-crosslinking of rubber and organic peroxide"). Agent, issued October 10, 1977, see Taisei Corporation)
Is used as it is as a binder for ceramic particles. Unlike the ceramic precursor binder, this method has tackiness and drapability, and is expected to have good shapeability. However, this binder is composed entirely of organic substances,
There is no difference from the polymer binder of the conventional slurry impregnation method. Therefore, after debinding by thermal decomposition,
The bonding strength between ceramic particles is rapidly reduced, and it is difficult to obtain fiber-reinforced ceramics having good mechanical strength unless a high-temperature and high-pressure sintering method used in a conventional slurry impregnation method is used.

[0024]

As described above, the conventional method for manufacturing a reinforced ceramic compact has the following problems.

That is, (1) a high temperature is required for sintering, (2) a long time is required for production, (3) calcination at normal pressure and free standing is difficult, and (4)
It is difficult to manufacture products with complicated shapes, (5) the use of expensive inert gas is a prerequisite, (6) the matrix material shrinks greatly during heating for ceramification and is strengthened. Due to the large difference in dimensional change during heating between the fiber and the matrix material, a large number of cracks are generated in the fired body.

All of these problems are disadvantageous to industrial production and practical use of products.
These are the main causes that have hindered the spread of ceramic composite materials.

In order to solve the above-mentioned problems at a time, the present invention comprises an inorganic fiber and a specific ceramic matrix composition, has excellent tackiness, drapability and out-time that can withstand practical use. Prepreg that can be molded into various shapes, a cured body of fiber-reinforced ceramics that has produced a strong cross-linked structure by heating and pressing the prepreg, and sintering manufactured by sintering the cured body under normal pressure It is an object of the present invention to provide a fiber-reinforced ceramic fired body having a small shrinkage at the time of manufacture, a method for producing the same, and a method for densifying the fired body further improved in strength by filling voids generated during firing.

[0028]

Means for Solving the Problems In order to solve the above problems, as a result of intensive studies by the present inventors, impregnation or heat infiltration of a specific matrix composition into a tow of inorganic fibers or a product of inorganic fibers. As a result, a prepreg having tackiness, drapability and long out time equivalent to those of a prepreg for an epoxy resin composite was successfully obtained. Here, the matrix composition is a composition containing the components (A) to (E) in the present invention and a solvent and an additive included as necessary.

The prepreg of the present invention can be used to produce a laminate having a complicated shape, and can be heated and pressed under substantially the same conditions as the prepreg for an epoxy resin composite to obtain a matrix composition. A strong cross-linked structure can be imparted to the cured product, and the cured product can be converted into a fiber-reinforced cured product having a good bonding property between the fiber and the matrix. This cured product has higher heat resistance than fiber reinforced epoxy resin composite materials that are widely used at present, and has its own practicality. From this cured product, it is also possible to produce a fiber-reinforced ceramic fired body under atmospheric pressure under unconstrained conditions, which is very easy to carry out industrially, and in this case, the shrinkage during firing is reduced. Almost no change in shape. Here, the heating under the unconstrained condition means that the cured body is heated and fired in a free standing state without taking measures to prevent deformation such as fixing with a mold or pressing with a press. Means that.

The fired body is further impregnated with a liquid containing at least one of the components constituting the matrix composition, and is fired again, thereby filling voids generated during firing and further improving the strength. . In this manner, fired fiber-reinforced ceramic products having various shapes can be easily manufactured. This product can be used for heat-resistant structural members and heat-shielding members of aircraft and spacecraft, jet engines, rocket engines, gas turbines, and the like. Heat-resistant and heat-shielding members such as engines, turbine blades, space equipment, heater or burner members, molding jigs, tools, or high-temperature furnace members such as furnace walls, furnace core protection tubes, and furnace inner vessels. Can be used for

The present invention which solves the above-mentioned conventional problems and has excellent technical effects as described above is as follows.

That is, the first aspect of the present invention provides a liquid or sheet of a matrix composition containing the following components (A), (B), (C), (D) and (E). A prepreg characterized by impregnating or heating-penetrating an object into an inorganic fiber tow or an inorganic fiber product.

Component (A): fine powder of a metal oxide having an average particle diameter of 1 μm or less; component (B): a soluble siloxane polymer having a double-chain structure; component (C): an ethylenically unsaturated double bond. At least one
A trifunctional silane compound contained in an individual molecule, (D) component; organic peroxide, (E) component; at least two ethylenically unsaturated double bonds.
A radical polymerizable monomer contained in an individual molecule.

According to the second aspect of the present invention, the amount of the component (A) in the matrix composition is 350 to 750 parts by weight, the amount of the component (B) is 80 to 170 parts by weight,
The amount of the component is 25 to 125 parts by weight, the amount of the component (D) is 1 to 4 parts by weight, and the amount of the component (E) is 25 to 1 part.
The prepreg according to claim 1, which is 25 parts by weight, wherein the component (A) is an oxide or a composite containing at least one selected from silica, alumina, and titanium oxide. The prepreg according to claim 1 or 2, which is an oxide. The invention according to claim 4, wherein the component (B) is a polysilsesquioxane. The invention according to claim 5, wherein the component (B) is a polyphenylsilsesquioxane, a polyethylsilsesquioxane, a polymethylsilsesquioxane, and a copolymer of monomers constituting these components. The prepreg according to claim 4, which is at least one member selected from the group consisting of: (C) wherein the component (C) is γ- (meth) a A prepreg according to claim 1 which is Lilo trialkoxysilanes,
The invention according to claim 7 is the prepreg according to claim 1, wherein the component (D) is a peroxide whose temperature for obtaining a half-life of 10 hours is 110 ° C or higher. The invention according to claim 8 is the prepreg according to claim 1, wherein the component (E) is di (meth) acrylate of polyhydric alcohol and / or tri (meth) acrylate of polyhydric alcohol. The invention according to the above, wherein the inorganic fibers are glass fibers, alumina fibers, silica fibers,
The at least one selected from the group consisting of Tyranno fibers and oxide-based inorganic fibers composed of various fibers containing alumina and / or silica as a main component.
The invention according to claim 10 is the prepreg according to claim 1, wherein the inorganic fiber product is any of a towed product and a knitted fabric. The invention according to claim 1, wherein the liquid obtained by dissolving or dispersing the component (A), the component (B), the component (C), the component (D) and the component (E) according to claim 1 in an inorganic solvent. A method for producing a prepreg, which comprises impregnating or applying to a fiber tow or an inorganic fiber product, and then heating after removing at least a part of the solvent.The invention according to claim 12, wherein Part of the solvent is removed from a liquid obtained by dissolving or dispersing the components (A), (B), (C), (D) and (E) in the solvent according to claim 1. To produce a sheet-like material, Method for producing a prepreg, characterized in that to heat penetration into the product of the machine fibers.

According to a thirteenth aspect of the present invention, the operation of heating and infiltrating the inorganic fiber of the sheet into the product is performed by superposing the sheet on one or both surfaces of the product of the inorganic fiber, The method of producing a prepreg according to claim 12, wherein the sheet-like material and the product of the inorganic fiber are alternately overlapped with each other, and then heated and infiltrated,
According to a fourteenth aspect of the present invention, a shaped body obtained by laminating or molding the prepreg of the first aspect into a predetermined shape is formed at a temperature of 120 to 250 ° C. and a pressure of 2 to 10 kg / cm.
A prepreg cured product characterized by being subjected to a heating and pressurizing treatment under the conditions of ² , wherein the invention according to claim 15 is characterized in that the prepreg cured product according to claim 14 is 500 to 1,
A prepreg fired body characterized by being heated to a temperature between 200 ° C., wherein the invention according to claim 16 is
A prepreg fired body characterized in that the prepreg cured body according to claim 14 is heated to a temperature of 500 to 1,200 ° C. in air, under normal pressure and under unrestricted conditions, The invention according to claim 17 is to heat the prepreg cured body according to claim 14 to 500 ° C. at a heating rate of 5 ° C./min or less, and then 500 to 1,200 ° C.
A method for producing a prepreg fired body characterized in that the prepreg fired body is heated to a temperature between the prepreg fired body and the prepreg fired body according to claim 15.
(A) component, (B) component, (C) component, (D)
It is at least required that the component and the component (E) are dissolved or dispersed in a solvent, or immersed in a liquid containing at least the component (B) and heated to a temperature of 500 to 1,200 ° C. This is a method for densifying a prepreg fired body, which is repeated once.

Hereinafter, the present invention will be described in detail according to the steps from the prepreg of the present invention, through the prepreg cured product to the prepreg fired product.

The matrix composition used for producing the prepreg of the present invention contains the following components (A), (B), (C), (D) and (E).

Component (A): fine powder of a metal oxide having an average particle size of 1 μm or less, component (B): a soluble siloxane polymer having a double-chain structure, component (C): an ethylenically unsaturated double bond. At least one
A trifunctional silane compound contained in an individual molecule, (D) component; organic peroxide, (E) component; at least two ethylenically unsaturated double bonds.
A radical polymerizable monomer contained in an individual molecule.

As the metal oxide as the component (A),
Single oxides such as silica, alumina, titanium oxide, lithium oxide, zinc oxide, tin oxide, calcium oxide, magnesium oxide, boron trioxide, zirconia, partially stabilized zirconia, vanadium pentoxide, barium oxide, yttria and ferrite And complex oxides such as mullite, steatite, forsterite, cordierite, aluminum titanate, barium titanate, strontium titanate, potassium titanate and lead zirconate titanate. One of these can be used alone, or two or more of them can be used in combination.

Preferred among these metal oxides are:
An oxide containing at least one selected from alumina, silica and titanium oxide or a composite oxide composed of these.

The metal oxide used in the present invention has an average particle size of 1 μm or less, preferably 0.5 μm or less. The fine powder of the metal oxide having such a fine particle size is densely packed by the component (B) in the three-dimensional network formed mainly by the components (C), (D) and (E). In a joined state, thus facilitating sintering. When the average particle size exceeds 1 μm, when a metal oxide particle is used, a prepreg fired body having good strength cannot be obtained by the production method of the present invention.

Since the metal oxide fine powder stored in the atmosphere has a hydroxyl group on at least a part of its surface, it effectively functions for the bonding effect described later. In contrast,
Fine powders such as metal nitrides and metal carbides do not have sufficient hydroxyl groups on a part of their surfaces, and thus the object of the present invention cannot always be sufficiently achieved. In addition, if an attempt is made to produce a ceramic body using only the fine powder of the metal oxide, a high-temperature and high-pressure sintering operation is required, so that the effects of the present invention cannot be achieved, and therefore, the object of the present invention is achieved. Can not do.

The soluble siloxane polymer having a double-chain structure as the component (B) may be a homopolymer or a copolymer. This component (B) functions as a binder for the metal oxide.

In general, a so-called ladder-type organic polymer having a double-chain structure has excellent heat resistance, is rigid, and has small heat shrinkage as compared with a linear organic polymer. However, organic polymers, even ladder-type,
When heated above ℃, it thermally decomposes or shrinks and generates a large amount of gas. Therefore, even if a prepreg fired body is manufactured using such a ladder type organic polymer as a binder, the prepreg fired body is Generates many cracks and bubbles.

The present inventors have conducted various studies on binders of fine powders of metal oxides. As a result, a siloxane homopolymer or siloxane copolymer having a double-chain structure has a high second order transition point (glass transition point), It has been found that it has a good bonding effect on oxides, and most of it is converted to a ceramic composition after thermal decomposition, so that it is most suitable as a binder for metal oxide fine particles used in the present invention. The soluble siloxane polymer having a double-chain structure in the present invention includes what is called an oligomer.

As a raw material for preparing a siloxane polymer having a double-chain structure, the chemical formula R'Si (OR) ₃
(Wherein R is an alkyl group such as a methyl group or an ethyl group,
R ′ represents an aliphatic, alicyclic, or aromatic substituent such as an alkyl group, a phenyl group, a vinyl group, a cyclopentyl group, a cyclohexyl group, and a methacryloyl group. )).

As the trialkoxysilane, methyltriethoxysilane, methyltrimethoxysilane, propyltrimethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, octyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane and the like can be mentioned.

The soluble siloxane polymer having a double-chain structure as the component (B) is described, for example, in JFB Rown et at.
Polymer Sci., Part C No. 1 p. 83 (1963), prepared by hydrolyzing one or more trialkoxysilanes using an acid catalyst and condensing them by a known method described in (1963). be able to. These are also called polysilsesquiosans, and are generally represented by the following chemical formula.

[0049]

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However, R ₁ represents a hydrogen atom or R in the above formula R′Si (OR) ₃ , and R ₂ and R ₃ represent R ′ in the above formula R′Si (OR) ₃ .

Examples of the polysilsesquioxane include polymethylsilsesquioxane, polyphenylsilsesquioxane, polyvinylmethylsilsesquioxane, polyphenylmethylsilsesquioxane, polyphenylpropylsilsesquioxane, and polymethylsilsesquioxane. -N-hexylsilsesquioxane, polyphenylmethacryloxypropylsilsesquioxane, and the like.

Among these, preferred are polyphenylsilsesquioxane, polyphenylmethylsilsesquioxane, and polyphenylethylsilsesquioxane. In the case of a copolymer, the molar ratio of phenyl group to methyl group or ethyl group (phenyl group / methyl group or ethyl group) is preferably 2/1 to 1/2. These are because the heat shrinkage rate during heating is small and the production is easy.

The molecular weight of the siloxane polymer that is preferable as the binder is not particularly limited, but is generally preferably 1,000 or more, and particularly preferably 1,500 or more.

For example, polyphenylsilsesquioxane is soluble in a solvent, can form a tough film from the solution, and has a glass transition point Tg of 300.
To 400 ° C., so that thermal deformation during curing and firing can be minimized. Furthermore, even when this polymer is heated to 900 ° C., the main chain does not break,
It converts in high yield to a ceramic structure such as, for example, amorphous silicone oxycarbide (Si-CO).

On the other hand, when an organic polymer is used as a binder, the organic polymer is thermally decomposed in a firing process at normal pressure,
The bonding strength between the metal oxides is lost, causing cracks.

As is clear from the above description, when the soluble siloxane polymer having a double-chain structure in the present invention is used as a binder, it shrinks little even when heated to a high temperature, and itself becomes ceramic. ,
Shrinkage of the compact is reduced. Therefore, the soluble siloxane polymer having a double-chain structure is particularly advantageous for a calcination operation under normal pressure and under unrestricted conditions. Here, the normal pressure includes a case where the operation of increasing or decreasing the pressure is not intentionally performed.

In the present invention, among the above-mentioned soluble siloxane polymers having a double-chain structure, those having a silanol group or an alkoxy group at the molecular terminal are particularly advantageous. The soluble siloxane polymer having a silanol group or an alkoxy group at a molecular terminal has an affinity for the component (A) having a hydroxyl group on at least a part of its surface, that is, fine particles of metal oxide and the soluble siloxane polymer, Easily inter-dispersed. Further, they react with each other at the time of heating and combine with each other, and at the time of firing, they are integrally ceramicized.

However, even a soluble siloxane polymer having a double chain structure having high heat stability can be used at 1,000 ° C.
When heated to a high temperature, the shrinkage is close to about 10%, which may cause dimensional changes in the fired body and may cause cracks and voids. Therefore, the object of the present invention can be achieved only by using the component (B). Can not do it.

In order to prevent the molded product from being deformed even at normal pressure and under unconstrained conditions at the time of firing up to 1,200 ° C., the inventors of the present invention pre-hardened the prepreg cured product in advance. It was recognized that it was effective to form a three-dimensional network structure.

In order to form a three-dimensional network structure, the component (C), a trifunctional silane compound having at least one ethylenically unsaturated double bond in a molecule, and a component (D) And a radical polymerizable monomer having at least two ethylenically unsaturated double bonds in the molecule, which is the component (E).

As already described in the prior art, a crosslinking system using a combination of a rubber or polymer with a crosslinking agent (peroxide) and a co-crosslinking agent (reactive monomer) is already known. A trifunctional silane compound having at least one ethylenically unsaturated double bond in the molecule, a component (D), an organic peroxide and a component (E). There is no known crosslinking system in combination with a radically polymerizable monomer having at least two ethylenically unsaturated double bonds in the molecule.

The silane coupling agent is a compound having in its molecule a reactive group chemically bonding to an inorganic substance such as a methoxy group and a reactive group chemically bonding to an organic substance such as a resin such as a vinyl group or an amino group. It is widely used to improve the adhesiveness between a substance and an organic substance such as a resin and increase the strength of a composite. The silane coupling agent is generally used for either or both of a method of treating the surface of an inorganic substance in advance and a method of mixing it with a resin.

In the present invention, the mutual affinity between the component (A) and the component (B), which are ceramic or ceramic precursor components, and the component (E), which is an organic substance, is increased.
An action and an effect that facilitate formation of a strong network structure in the matrix and enhance bonding between the matrix material and the inorganic fibers are required.

All of the known silane coupling agents cannot be used in order to achieve such an action or effect. In the present invention, a trifunctional silane compound having at least one ethylenically unsaturated double bond in a molecule is used as the component (C). The component (C) easily bonds to the molecular terminals of the soluble siloxane polymer having a double-chain structure, which is the component (B), and the metal oxide fine particles. These bonds are formed by dehydration condensation of hydroxyl groups upon heating. In addition, the trifunctional silane compound as the component (C) easily reacts with the surface hydroxyl group of the inorganic fiber, so that the bonding property between the matrix composition and the inorganic fiber can be improved. Therefore, in this regard, oxide-based inorganic fibers are preferable to nitride-based inorganic fibers and carbide-based inorganic fibers. Further, the ethylenically unsaturated double bond contained in the component (C) reacts with the radical catalyst as the component (D) and is incorporated into a network structure.

Examples of the trifunctional silane compound having at least one ethylenically unsaturated double bond in a molecule include vinyl tris (β-methoxyethoxy) silane, vinyl trimethoxy silane, vinyl triethoxy silane, γ-methacryloxypropyl Examples thereof include trimethoxysilane and γ-methacryloxypropyltriethoxysilane. Among them, γ-methacryloxyalkyl trialkoxysilane is preferable, and γ-methacryloxypropyltrimethoxysilane and γ-methacryloxypropyltriethoxysilane are particularly preferable.

In order to form a network structure in the cured product, a crosslinking agent is required. In the present invention, the organic peroxide as the component (D) is effective as a crosslinking agent.

In the present invention, in order for the organic peroxide to work effectively, it is not preferable that the organic peroxide decomposes during the operation before curing to generate radicals. Therefore, the temperature for obtaining a half-life of 10 hours is not preferable. Is preferably 110 ° C. or higher.

Examples of such an organic peroxide include dicumyl peroxide, t-butylcumyl peroxide,
Di-t-butyl peroxide, α, α-bis (t-butylperoxyisopropyl) benzene, di-t-butylperoxydiisopropylbenzene, 2,5-dimethyl-2,5-di (t-butylperoxy ) Hexin-
3,1,1-bis (t-butylperoxy) -3,3,3
Examples thereof include 5-trimethylcyclohexane, 2,2-bis (t-butylperoxy) butane, and 2,2-bis (t-butylperoxy) octane.

The matrix composition according to the present invention comprises:
In addition to the organic peroxide which is a cross-linking agent as the component (D), a radical polymerizable monomer having at least two, preferably three ethylenically unsaturated double bonds as the component (E) is contained. . This component (E), as a co-crosslinking agent, contributes to the formation of a stronger three-dimensional network structure by curing. The matrix composition containing the component (E) contains fine particles of metal oxide and changes to a network structure having an effective and sufficient chain length that does not deform when heated.

The component (E) includes ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, ethylene glycol diitaconate, tetramethylene glycol diitaconate, ethylene glycol dicrotonate, and ethylene glycol dicrotonate. Maleate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and the like can be mentioned. In the above example,
The expression (meth) acrylate refers to both acrylate and methacrylate.

Among these, radical polymerization is excellent,
Di (meth) acrylates of polyhydric alcohols and / or tri (meth) acrylates of polyhydric alcohols, such as trimethylolpropanetriene, provide an effective chain length and excellent tackiness to a prepreg as described below. (Meth) acrylates are preferred.

The components constituting the matrix composition described above are dissolved or dispersed in an organic solvent.

The type of the solvent may be appropriately selected depending on the type of each component and the mixing ratio thereof. Solvents suitably used in the present invention are selected from alcohols, aromatic hydrocarbons, alkanes, ketones, nitriles, esters, glycol esters and the like. Preferably, the solvent is completely removed prior to curing, and thus a solvent such as, but not limited to, acetone with a low boiling point is preferred. These solvents may be used alone or in combination of two or more.

In the present invention, the component (A)
It is desirable that the component (E) is dissolved or dispersed in the solvent as uniformly as possible so as to give a dense structure to the fired ceramic matrix body. For this purpose, the components (B), (C), (D) and (E) are each dissolved in a solvent while stirring, and the component (A) is added to the obtained solution. A method of continuing stirring until the particles are uniformly dispersed may be employed. Alternatively, a method of simultaneously adding all of the components (A) to (E) to the solvent and stirring sufficiently may be employed. The effects of the invention can be achieved. Further, a trace amount of a dispersion stabilizer such as a known surfactant may be added. Furthermore, as long as the properties of the matrix composition are not impaired, addition of known additives is not prevented.

The ratio of each component in the matrix composition is as follows:
It is appropriately selected depending on the type of each component and the performance of a prepreg cured product or a prepreg fired product which is composited therewith. In many cases, the matrix composition has the following component proportions.

That is, the amount of the component (A) is from 350 to
750 parts by weight, preferably 450 to 650 parts by weight,
The compounding amount of the component (B) is 80 to 170 parts by weight, preferably 100 to 150 parts by weight, and the compounding amount of the component (C) is 25 to 1
25 parts by weight, preferably 50 to 100 parts by weight, the amount of component (D) is 1 to 4 parts by weight, preferably 1.5 to 3 parts by weight, and the amount of component (E) is 25 to 125 parts by weight; Preferably it is 50 to 100 parts by weight.

The tackiness of the prepreg is adjusted by the amount of the component (E) in combination with other components. Therefore, the role of the component (E) is not limited to the formation of a network structure, but also plays an important role in forming tackiness, which is an important effect of the present invention.

As will be described later, the matrix composition of the present invention can be used while having a solvent, or can be used as a sheet by removing the solvent.

The prepreg of the present invention is produced by impregnating or heating-infiltrating a liquid or a sheet of the matrix composition into a tow of inorganic fibers or a product thereof.

The inorganic fibers may be heated to at least 500 ° C. or lower, preferably 1,000 ° C. or lower, more preferably 1200 ° C. or lower in either an inert atmosphere or an oxidizing atmosphere such as air. It is preferable to use a material which has sufficient strength for practical use. Examples of materials satisfying such conditions include nitride-based inorganic fibers, carbide-based inorganic fibers, oxide-based inorganic fibers, and carbon fibers. These inorganic fibers have sufficient heat resistance and reinforcing effect required in the present invention.

Preferred inorganic fibers include glass fibers and
Alumina fiber, silica fiber, Tyranno fiber (Si-Ti-
CO), and oxide-based inorganic fibers composed of various fibers containing alumina and / or silica as a main component. Although the strength of the glass fiber decreases at high temperatures, the strength at room temperature is higher than that of other oxide-based inorganic fibers.
Even at a temperature near 00 ° C., the strength is sufficient to achieve the object of the present invention.

When a commercially available product is used as the inorganic fiber,
It is preferable that the sizing agent attached is removed before use.

A feature of the fiber reinforced ceramics is that the fiber bears a load while the breaking process is controlled by the frictional force between the fiber and the interface of the matrix. Therefore, in the case of fiber-reinforced ceramics, unlike fiber-reinforced plastics and fiber-reinforced metals, the bonding force between the fiber and the interface between the matrix and the fiber is not too strong, and fiber withdrawal (Pu
It is particularly important that the control is performed to the extent that it is possible to guarantee the ll-out) (Koichi Niihara, NIKKEI MECHANIC)
AL 1989 12.11 p114). This means that even if it is desired that the fibers and the matrix composition are sufficiently bonded in the prepreg and the cured prepreg,
This indicates that it is preferable that the fiber and the matrix are rather weakly bonded in the prepreg fired body.

As a fiber surface coating agent capable of forming such an interface, carbon and boron nitride are known. In air, carbon is oxidized above about 450 ° C. and boron nitride above about 900 ° C., thereby providing a weak interface between the fibers and the matrix.
It is effective to apply such a known fiber surface coating to the inorganic fibers used in the present invention in advance to further improve the mechanical properties of the fired prepreg.

The inorganic fibers are used as a towed product, or in the form of a knit or a woven fabric.

[0086] The prepreg of the present invention includes a solvent method (also referred to as a wet method) and a hot melt method (also referred to as a dry method) employed in the production of conventional epoxy resin prepregs. It can be manufactured using a similar technique.

In a method according to the solvent method, tow of inorganic fiber or a product thereof is immersed in a liquid of a matrix composition,
After squeezing out excess liquid, by blowing hot air or passing through a dryer to remove the solvent,
A prepreg is obtained.

Further, in the hot melt method, a sheet-like material having a predetermined basis weight (this term includes a film-like material as a concept) is formed from a liquid of the matrix composition, and tow of inorganic fiber or inorganic fiber is formed. By laminating the sheet-like material on one or both surfaces of the product, or alternately laminating the sheet-like material and the inorganic fiber tow or inorganic fiber product, and heating it to a temperature of usually 120 ° C or less. A prepreg can be obtained by infiltrating the matrix composition between the inorganic fibers while lowering the viscosity of the sheet material.

The prepreg thus obtained has sufficient tackiness and drapability for forming a laminate and sufficient outtime for work.

The prepreg manufactured as described above is
After being formed into a predetermined shape by using a known laminating method or a filament winding method, a heating and pressing treatment, that is, a curing treatment is applied. It should be noted that in the present invention, the curing reaction is sufficiently completed by the one-stage curing, so that the two-stage curing (including the preliminary curing) and the three-stage curing (including the preliminary curing and the post-curing) are not required. That is. However, in some cases, these pre-curing and post-curing may be performed.

Preferred curing conditions include a heating temperature of 120 to 250 ° C. and a pressure of 2 to 10 kg / c.
m ² , and a treatment time of 10 to 60 minutes can be pointed out.

The curing operation is performed in an autoclave after the vacuum bag or by using a hot press.

The former is advantageous for industrial production because a complicated and large product can be manufactured.

The obtained cured prepreg has no shrinkage and no surface cracks, and hardly loses its weight. Specifically, the cured product is, for example, 25 to
It has a bending strength of about 50 kg / mm ² , and hardly shrinks when heated to 1,000 ° C. in air under normal pressure.

The reason why the cured prepreg hardly causes thermal shrinkage is that the metal oxide fine particles maintain a high density and sufficient contact state in a strong three-dimensional network structure formed by curing. This is considered to be because the filler is filled, and the inorganic fiber and the matrix maintain a good bonding state and do not cause separation or separation.

The obtained prepreg cured product is 500 to
By heating to a temperature of 1200C, preferably between 600C and 1000C, it is converted into a fired body reinforced with inorganic fibers. 1,200 ° C as heating temperature
Although the temperature may be higher than the above, heating to an excessively high temperature may lower the strength of the inorganic fibers, which is not preferable in some cases. Also, 500 ° C at the initial stage of temperature rise
By heating at a temperature rising rate of 5 ° C./min or less, preferably 2 ° C./min or less, particularly in a temperature range of 100 to 450 ° C., deformation and cracks can be effectively prevented. Under such heating conditions, the prepreg cured product can be heated under normal pressure and under unrestricted conditions. The prepreg cured body heated to a predetermined temperature in this way is kept at that temperature for preferably 10 minutes or more, and then cooled according to a conventional method.

The heating atmosphere may be an oxidizing atmosphere such as air and an inert gas atmosphere. However, the prepreg fired body obtained in an inert atmosphere has a carbon content remaining in the matrix without being released by thermal decomposition and exhibits a black color. When this prepreg fired body is fired again in the air, the carbon content is released and the fired prepreg becomes white. Therefore, if the prepreg fired body is used as it is in the high-temperature atmosphere in this inert atmosphere, the residual carbon content is oxidized and released as a gaseous body. In addition, a prepreg fired body in an inert atmosphere tends to have lower strength than a prepreg fired body in air.
In view of these points, firing in an inert atmosphere can be performed, but is not necessarily advantageous in terms of the number of steps and performance as compared with firing in air.

One of the important effects of the present invention is that the sintering operation can be carried out in air, under normal pressure, and under unconstrained conditions without deformation. by this,
A large-sized ceramic component having a complicated shape can be easily manufactured.

To achieve this effect, components (A), (B),
All of the five components (C), (D) and (E) are indispensable, and the object of the present invention cannot be achieved if any one of the components is missing. The fired prepreg body obtained by the present invention can be sufficiently put to practical use as it is, but its performance can be further improved by the following densification treatment.

The cured prepreg contains an organic component at a ratio of 10 to 15%, depending on the mixing ratio of the constituent components. Although a part of this is taken into the ceramic composition, the remainder is released as a gas during firing, so that fine voids are generated in the fired body. These fine voids are composed of the component (A) constituting the matrix composition.
The prepreg fired body is immersed in a liquid containing the component (E) or at least a liquid containing the component (B),
It can be filled by refiring at a temperature of 1200C, preferably between 600C and 1200C. This densification process may be repeatedly performed.

The fired prepreg of the present invention can be used for heat-resistant structural members and heat-insulating members of aircraft and space shuttles, jet engines, rocket engines, heat-resistant members and heat-insulating members of gas turbine engines, turbine blades, space equipment, heaters, It is suitably used for burner members, molding jigs, tools, and high temperature furnace members (furnace walls, furnace core tubes, protective tubes, furnace inner containers, etc.).

[0102]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically below with reference to embodiments of the present invention. It goes without saying that the present invention is not limited to the following embodiments.

Example 1—Preparation of Matrix Composition I
In a ball mill containing ceramic balls, 400 parts by weight of alumina powder (average particle diameter: 0.4 μm), 200 parts by weight of titanium oxide powder (average particle diameter: 0.4 μm), polyphenylmethylsilsesquioxane (molecular weight: 2,300) Phenyl / methyl ratio = 6/4) 125 parts by weight, γ-methacryloxypropyltrimethoxysilane 40 parts by weight, trimethylolpropane trimethacrylate 50 parts by weight, 2,5
-Dimethyl-2,5-di (t-butylperoxy) -hexyne-3 (2 parts by weight) and acetone (250 parts by weight) were added and mixed by rotating a ball mill for 1 hour.
A liquid matrix composition I which was uniformly dissolved and dispersed was obtained.

Example 2 Preparation of Matrix Composition II
125 parts by weight of polyphenylethylsilsesquioxane (molecular weight: 1,700, phenyl / ethyl ratio = 5/5) in a glass cylindrical container equipped with a stirrer, 100 parts by weight of γ-methacryloxypropyltriethoxysilane, 30 parts by weight of trimethylolpropane triacrylate, 1.3 parts by weight of dicumyl peroxide and 250 parts by weight of acetone were added and stirred until a homogeneous solution was formed. To this solution, 300 parts by weight of alumina powder (average particle size: 0.4 μm) and 200 parts by weight of silica powder (average particle size: 0.02 μm) were added with stirring, and the mixture was dispersed well by applying ultrasonic vibration to obtain a matrix composition. II was prepared.

Example 3 Preparation of Matrix Composition III By slowly stirring the matrix composition prepared by the method of Example I, acetone in the matrix composition was removed until the solution viscosity reached 300 poise. Evaporated. As a result, a dense matrix composition III having good film-forming ability was obtained.

Example 4 Preparation of Prepreg I The matrix composition I prepared in Example 1 was added to a woven fabric (Altex cloth, SV-600-8H, alumina fiber (85% by weight of alumina, 15% by weight of silica)). (Sumitomo Chemical Industry Co., Ltd.), the excess matrix was removed using a squeeze roll, and the acetone was evaporated by placing it in a hot air circulating drier at 80 ° C. for 5 minutes to evaporate the acetone. An inorganic fiber reinforced prepreg was manufactured.

The tackiness, drapability and out time of this prepreg were evaluated by a method similar to that of the conventional epoxy prepreg, and the results are shown in Table 1. As shown in Table 1, good results were obtained.

[0108]

[Table 1]

Example 5 Preparation of Prepreg II Example 3
Using a film coater, a film having a thickness of 0.15 mm was prepared from the matrix composition III prepared in the above. This film was affixed to both sides of the same alumina fiber fabric used in Example 4, and impregnated with a hot roll at a temperature of 120 ° C. to prepare a prepreg having a matrix composition content of 50%. It was confirmed that this prepreg had tackiness, drapability and out time which passed the evaluation method shown in Example 4 above.

(Example 6--Preparation of prepreg III) Alumina fiber degreased in advance (85% by weight of alumina, silica 1
5% by weight) of a tow (Altex SV-10-1K, manufactured by Sumitomo Chemical Co., Ltd.) in the liquid matrix composition I prepared in Example 1 to impregnate the tow with the composition I. On a 30 cm diameter drum on which release paper is wound with a filament winder.
After winding the tow at a pitch of mm, it was cut and removed from the drum. This was put in a hot air circulating dryer at 80 ° C. for 5 minutes to evaporate acetone, thereby producing a unidirectional prepreg having a matrix composition content of 50%. It was confirmed that this prepreg also had tackiness, drapeability, and outtime that were acceptable by the evaluation method shown in Example 4.

(Example 7--Production of cured prepreg I) The prepreg produced in Example 6 was laminated in nine layers in the direction of 0 ° in a vacuum bag according to a conventional method, placed in an autoclave, and raised at a pressure of 7 kg / cm ² . The temperature was raised to 220 ° C. at a temperature rate of 2.5 ° C./min, held for 30 minutes, and then lowered at 4.5 ° C./min to produce a 3 mm thick prepreg cured plate. A test piece having a width of 4 mm and a length of 36 mm was cut out from the cured prepreg and subjected to the same bending test in the following examples in accordance with JIS R 1601, and found to be 57.7.
The flexural strength was kg / mm ² . In addition, the measurement values shown below this example are average values of five samples.

(Example 8--Production of Precured Prepreg II) Four layers of the prepreg produced in Example 4 were laminated in the directions of 0 ° and 90 °, and 3.5 kg by hot pressing at 200 ° C. for 15 minutes.
/ Cm ² , a prepreg cured product having a thickness of 2 mm was produced. The obtained prepreg cured product has good mechanical strength, no shrinkage and no occurrence of surface cracks are observed,
The weight loss was 0.7%. When the flexural strength of the cured prepreg was measured in the same manner as in Example 7,
It was 28.0 kg / mm ² .

(Example 9--Production of cured prepreg III)
Four layers of the prepregs manufactured in Example 5 were laminated in the directions of 0 ° and 90 °, and hot press was performed at 150 ° C. for 15 minutes at 3.5 k.
Under the condition of g / cm ² , a prepreg cured product having a thickness of 2 mm was produced. The obtained cured prepreg had good mechanical strength, no shrinkage and no surface cracks were observed, and the weight loss was 0.6%. When the flexural strength of the cured prepreg was measured in the same manner as in Example 7, it was 32.3 kg / mm ² .

Example 10 Baking of Precured Prepreg I
The prepreg cured product produced in the above Example 7 was heated to 500 ° C. at a heating rate of 1 ° C./min in air under normal pressure, and then heated to 1,000 ° C. at 2 ° C./min. The alumina fiber reinforced ceramic laminate (prepreg fired body) was manufactured by firing by holding for a time.

The dimensional change between the cured prepreg and the fired prepreg was hardly observed. The weight was reduced by 7.3% as compared to before the firing.

--High-Temperature Strength Test-- Table 2 shows the results of a high-temperature bending test performed on this laminate at 800 ° C. and 1,000 ° C. Bending test is J
Performed according to IS R 1604. As shown in Table 2, there was a tendency for the strength to increase as the temperature increased. This is presumed to be caused by the fact that the bonding between the fiber and the matrix is reduced by the increase in the temperature, and the pull-out effect of the fiber is increased and / or the elongation of the matrix is increased.

[0117]

[Table 2]

--- Heat cycle test-- With respect to this laminate, the room temperature bending strength in each cycle when the heat cycle was changed between room temperature and 1,000 ° C. to 5, 10, 15, 20 times The measurement was performed, and the results shown in Table 3 were obtained. As shown in Table 3, no decrease in strength was observed in the heat cycle between room temperature and 1000 ° C.

[0119]

[Table 3]

Example 11 Baking of Prepreg Cured Body II
The cured prepreg prepared in Example 9 was heated to 800 ° C. at a heating rate of 1.5 ° C./min. In the air at normal pressure and kept at that temperature for 1 hour for firing to obtain an alumina fiber reinforced ceramic. A laminate (prepreg fired body) was manufactured.
The dimensional shrinkage between the cured prepreg and the fired prepreg was 0.03% in the length direction and 0.8% in the thickness direction.

A high-temperature strength test and a heat cycle test were performed on the laminated plate according to the method shown in Example 10.
And as shown in Table 5, the same tendency as that shown in Tables 2 and 3 was observed.

[0122]

[Table 4]

[0123]

[Table 5]

Example 12 Densification Treatment I In a glass cylindrical vessel equipped with a stirrer, polyphenylmethylsilsesquioxane (molecular weight 1,700, phenyl / methyl ratio =
5/5) 125 parts by weight, 100 parts by weight of γ-methacryloxypropyltrimethoxysilane, 1.3 parts by weight of dicumyl peroxide and 250 parts by weight of acetone were added and stirred until a uniform solution was formed.

After the alumina fiber-reinforced ceramic laminate of Example 11 was immersed in the above-mentioned solution contained in a glass cylindrical container, it was kept under reduced pressure until no bubbles were generated. Next, the vacuum was released, the laminate was taken out, the solution adhering to the surface was removed, and the acetone was completely evaporated in a dryer at 80 ° C. The impregnated laminate was placed in an electric furnace, heated to 800 ° C. in air at a rate of 1 ° C./min, and held for 1 hour to produce a densified ceramic laminate. This sample was used as the first impregnated sample, and the same impregnation, drying and firing operations were performed for
Was repeated three times. These were sampled in the second impregnation,
The sample was repeatedly impregnated. Table 6 shows the bending test results of each impregnated sample. It can be seen that the bending strength of the laminate improved with the number of times of impregnation.

[0126]

[Table 6]

Example 13 Densification Treatment II The alumina fiber reinforced ceramic laminate of Example 11 was placed in a vacuum chamber, the inside of which was evacuated, and methylphenylvinylhydrogenpolysiloxane (H62C) preheated to 80 ° C. , Wacker
-Chemie GmbH) and left overnight. Next, after releasing the inside of the vacuum chamber to atmospheric pressure, the laminate was taken out, and the solution attached to the surface was removed. Next, the impregnated laminate was placed in an electric furnace, heated to 800 ° C. in air at a rate of 1.5 ° C./min, and kept at that temperature for 1 hour. The mechanical properties of the laminate before and after densification are described in Example 17, Table 11.

Example 14 Densification Treatment III The alumina fiber reinforced ceramic laminate of Example 10 was placed in a vacuum chamber, and a densified ceramic laminate was produced in the same manner as in Example 13.

This sample was used as a first impregnated sample, and the same operation was repeated twice to obtain a second impregnated sample. Table 7 shows the bending test results of each impregnated sample.

[0130]

[Table 7]

(Example 15--Example in which inorganic fiber is glass fiber)
400 parts by weight of alumina powder (average particle size: 0.4 μm), 200 parts by weight of titanium oxide powder (average particle size: 0.4 μm), polyphenylsilsesquioxane (molecular weight: 1,700) were placed in a ball mill containing ceramic balls. ) 125 parts by weight, 50 parts by weight of γ-methacryloxypropyltrimethoxysilane, 50 parts by weight of trimethylolpropane triacrylate, 2 parts by weight of dicumyl peroxide, and 250 parts by weight of methanol are mixed by rotating a ball mill for 1 hour. Thus, a uniformly dissolved and dispersed matrix solution was obtained.

A glass fiber fabric (6781HT-38, manufactured by Hexel) was immersed in this matrix solution.
Excess matrix solution was removed using a squeeze roll, and dried in a hot air circulating dryer at 80 ° C. to prepare a prepreg having a matrix composition content of 65% by weight.

It was confirmed that this prepreg also had tackiness, drapeability, and outtime which passed the evaluation method shown in Example 4.

This prepreg is set to 8 ° in the directions of 0 ° and 90 °.
The layered product was vacuum bagged by a conventional method, placed in an autoclave, and set at a pressure of 5 kg / cm ² and a temperature rising rate of 2.5 ° C /
After raising the temperature to 150 ° C. for 15 minutes and holding for 15 minutes, 4.5
The temperature was lowered at a rate of ° C./min to prepare a 3 mm thick prepreg cured product plate.

In the obtained cured prepreg, no shrinkage and no surface cracking were observed, and the weight loss was 1.1%.

The cured prepreg was heated in air at normal pressure and at a heating rate of 1.5 ° C./min.
The temperature was raised to each temperature of 00 ° C. and kept at that temperature for 1 hour.

The weight reduction rate was measured using a thermal analyzer TG / DTA3.
0 (manufactured by Seiko Denshi Kogyo Co., Ltd.) in an air stream at a heating rate of 1.5 ° C./min. In this case, 40
Temperature rise tests up to each temperature of 0, 500, 600, and 800 ° C. were performed. Table 8 shows the values of the weight loss rate and the bending strength of the fired laminate (fired prepreg). In addition, the weight reduction rate was shown by the value from the cured laminate.

[0138]

[Table 8]

The rate of weight loss increases as the temperature increases, but reaches a constant value at 600 ° C. Further, the color of the test piece after firing was still colored by the treatment at 500 ° C. for 1 hour, but turned white at 600 ° C. or more.

These results indicate that at 500 ° C. or lower, the organic component in the matrix or its decomposition product remains,
Above 600 ° C., these were completely released, indicating conversion to the ceramic composition. The bending strength of the fired product at 600 ° C. or higher is lower than that of the fired product at 500 ° C. or lower, which is considered to be due to the occurrence of defects due to the release of organic components. Note that a heat treatment time of 10 minutes or more at 600 ° C. is sufficient for releasing organic components and converting the preceramic component to a ceramic composition. This result also suggests that a firing temperature of at least 500 ° C. is required even if the heat treatment is performed at a lower temperature for a long time.

[0141] Glass fibers have a large decrease in strength with increasing temperature as compared with ceramic fibers such as alumina fibers, but since their room temperature strength is much higher than that of ceramic fibers, they have strength enough to withstand practical use even at 600 ° C. For example, S-glass fiber (manufactured by Owens Corning Fiberglass) or T-glass fiber (manufactured by Nitto Boseki Co., Ltd.) holds a tensile strength of about 200 kg / mm ² ). Therefore, the fact that the preceramic component, that is, the component (B) and the component (C) in the present invention can be made into a ceramic even by heat treatment at 600 ° C. for a short time means that glass fiber, which has lower heat resistance than ceramic fiber but is inexpensive, can be used. It shows that it is.

Example 16 Influence of Firing Atmosphere Four layers of the prepregs produced in Example 4 were laminated and hot-pressed under the conditions of Example 9 to obtain a length of 160 mm, a width of 160 mm, and a thickness of 2 mm.
After preparing the cured laminate, the plate was separated into two parts.
One was heated to 800 ° C. in air at a rate of 1 ° C./min, and kept at that temperature for 1 hour. The other was fired in nitrogen under the same conditions. In each case, the densification treatment under normal pressure was performed once by the same method as in Example 13.

Table 9 shows the change in weight (assuming the weight of the cured product is 100) due to the firing and densification treatments, and the bending test results (by the method described in Example 7) of the densified treatments.

[0144]

[Table 9]

The reason why the change in weight in the firing in nitrogen is smaller than that in the air is that the organic component contained in the matrix component is carbonized. This was confirmed from the fact that when the fired product in nitrogen having a black color was further fired in air at 800 ° C. for 1 hour, the color changed to the same white color as the fired product in air.

In addition, the product fired in nitrogen had a lower strength and a higher elastic modulus than those fired in air. This means that firing in air is greater in elongation than firing in nitrogen, thus indicating that the former is more tenacious than the latter.

(Example 17, Comparative Examples 1-3-Influence of Matrix Component I) The preparation of the matrix composition was carried out by the method described in Example 1 using the matrix components and the mixing ratios shown in Table 10. . The production of the prepreg and the cured laminate (cured prepreg) were performed by the methods described in Examples 4 and 8, respectively. For Example 17 and Comparative Example 1 shown in Table 10, each cured laminate was heated to 800 ° C. in air at a rate of 1.5 ° C./min, and held at that temperature for 1 hour. A board was created. The densification treatment was performed by the method of Example 13.

[0148]

[Table 10]

The following results were obtained by comparison under the same method and under the same conditions.

Comparative Example 3: The prepreg impregnated with only the component (B) had almost no tackiness, and the fibers were twisted to make cutting more difficult than in the other examples. Also, when laminating prepreg and curing using hot press,
When the temperature was increased, the matrix (and fiber) flow was too high, out of the mold, and it was impossible to produce a good laminate. Therefore, the firing operation in the next step could not be performed.

Comparative Example 2: The prepreg impregnated with the components (A) and (B) also had poor tackiness, but could be cut easily. However, the cured product after lamination and hot pressing peeled off from one layer to another, and an integrated laminate could not be obtained. Therefore,
The firing operation in the next step could not be performed.

Comparative Examples 1 and 17: In Comparative Example 1, although the prepreg had poor tackiness and was difficult to handle, it could be cut easily, and the curing operation could be carried out well and integrated. A cured laminate was obtained.
In Example 17, all of tackiness, cutability, and curing operation were excellent, and a favorable cured laminate could be obtained.

With respect to these two types of cured laminates, Example 1
The sintering and densification treatments were performed by the methods described in Examples 1 and 13. The measurement was carried out with respect to the shrinkage ratio during firing and the flexural strength, flexural modulus and hardness of the cured product, the baked product and the densified product. Hardness is Vickers hardness meter AVK-CT
(Manufactured by Akashi Manufacturing Co., Ltd.). The results are shown in Table 11.

[0154]

[Table 11]

The firing shrinkage is slightly higher in Example 17 than in Comparative Example 1. This is considered to be due to the effect that the component (E), which is an organic substance contained in the former, is released during firing. However, in both cases, the shrinkage ratio is extremely small, and it can be concluded that there is almost no dimensional change due to firing.

A clear difference between the two examples is the mechanical properties of the laminate. At any stage of curing, firing and densification, the flexural strength, flexural modulus and Vickers hardness of each laminate were significantly higher in Example 17 than in Comparative Example 1, which was It means that the excellent mechanical properties of the produced cured product are maintained after firing and after densification. In particular, it was recognized that the densification treatment of Example 17 had a higher strength increasing effect than Comparative Example 1. That is,
The flexural strength is improved by about 50% in the former, but remains at about 20% in the latter. The reason for this is not clear, but it is presumed that the fired product obtained in the former has a higher porosity than the porosity, whereas the latter has a higher porosity than the porosity. You.

The above results show that when a cured product having a complicated shape is produced by using the method of Example 17, the prepreg has good tackiness and is easy to handle. Even if the firing operation is performed under the constraint, the shape does not lose shape, that is, the self-shape retention property is effectively maintained, and there is almost no dimensional change, that is, there is no shape collapse. This indicates that the generation of cracks caused by shrinkage can be minimized, and as a result, a long fiber reinforced ceramic product having good mechanical properties can be produced. That is, the addition of the component (E) gives not only excellent mechanical properties to the laminate at each stage, and also facilitates the improvement of the strength by the densification treatment, and also provides the prepreg with good tackiness and drapability. In order to improve the shapeability and thereby give the product good mechanical properties.

Comparative Example 4 Influence of Matrix Component I
I) The prepreg, the prepreg cured product and the prepreg fired product were produced by the method described in Example 17. However, Example 1
Mullite was used in place of alumina and titanium oxide as the component (A) among the matrix components of No. 7. The mixing ratio of mullite (3Al ₂ O ₃ .2SiO ₂ ) was the same as the total amount of alumina and titanium oxide. As mullite, a powder having an average particle size of 1.2 μm (out of the range specified in the present invention) was used. The other components and the mixing ratio are the same as in Example 17.

When the matrix composition described in Example 17 was used, when the thickness of the laminated prepreg was 1.8 mm when hot-pressed, when the component (A) was changed to mullite powder, the same conditions were obtained. Even with hot pressing, no flow of the matrix was observed, and the thickness was only 3.1 mm. Also. When a test piece is cut out from the fired laminate, it is almost broken, and even a test piece that has been cut out has a flexural strength of 1.1 kg / mm ² and a flexural modulus of 1370 k.
g / mm ² . This is attributable to the large particle size rather than the oxide composition. The result is
It indicates that metal oxide fine particles having a particle size of 1 μm or less, preferably 0.5 μm or less should be used.

Example 18 Influence of Matrix Component III
) The prepreg, the cured prepreg, the fired prepreg, and the densified body were manufactured by the method described in Example 17. However, among the matrix components of Example 17,
(E) The same amount of ethylene glycol dimethacrylate was used instead of trimethylolpropane trimethacrylate as a component. The bending strength of the laminate after densification is 2
0.2 kg / mm ² , flexural modulus 5980 kg / mm
^{Was 2} . These values are at the same level as those obtained in Example 17, indicating that the latter compound can be used sufficiently. However, although the latter compound had no practical problem compared to the former compound, it was recognized that the tackiness was somewhat small.

(Comparative Example 5, 6--Comparison with Polymer Binder) In the conventional slurry method, a polymer binder is often used. Then, this effect was examined by using polyurethane as a polymer and combining it with the component (D) and the component (E) (Comparative Example 5). A test was also conducted on a system in which the component (C) was used instead of the polymer, and the component (D) and the component (E) were combined with the component (Comparative Example 6).

The preparation of the matrix composition was carried out by the method described in Example 1. Table 12 shows the mixing ratio of the matrix components.

[0163]

[Table 12]

A prepreg was produced according to the method described in Example 4 using the above matrix liquid and the woven fabric of alumina fibers described in Example 4. The content of the matrix (solid content) was 60% by weight. This prepreg is 0 degree,
Laminate 4 sheets each in the direction of 90 degrees, and press 1
Molding and curing were performed at 50 ° C. for 15 minutes at 3.5 kg / cm ² . Thereafter, it was heated to 800 ° C. in air at a normal temperature and at a rate of 1.5 ° C./min, and kept at that temperature for 1 hour.

When the matrix composition of Comparative Example 5 was used, there was no flow of the matrix, but
It exhibited some tackiness, and molding was possible. However, when this was fired, in the obtained fired product, although the layer did not peel off, it was not hard, only a soft material with high flexibility was obtained, and the matrix collapsed and fell off with a slight force . This is because using an organic binder
At normal pressure and low temperature firing, it seems that after these pyrolysis release, the force for bonding the ceramic particles is lost. When such an organic binder is used, the normal-pressure low-temperature sintering used in the present invention is inappropriate, and as shown in the conventional slurry method, a high-pressure high-temperature sintering operation is required. I have.

Also in Comparative Example 6, there was no flow of the matrix, but molding and curing were possible.
However, when this was fired, the four layers were peeled off. This indicates a lack of bonding force (binding force). Therefore, this result indicates that the components (A), (B), and (C) must be used in order to achieve the objects and effects of the present invention.
This indicates that five components, component (D) and component (E), are essential components.

As is clear from the above examples, according to the present invention, a practically practicable long-fiber reinforced ceramic product can be produced industrially easily and at a low cost. That is, according to the present invention, the following technical effects can be achieved.

(1) The prepreg has excellent shapeability,
Therefore, a product having a complicated shape can be easily manufactured, and (2) one-stage heating at a low temperature is sufficient for curing,
Therefore, a cured product can be easily produced in a short time, and (3) baking can be carried out in air, under normal pressure and under unconstrained conditions, with almost no deformation or dimensional change. The fired body thus obtained is integrated, does not peel off the layers, and has physical properties (for example, strength, heat cycle characteristics, etc.) sufficient and effective for practical use.

It should be noted that a long-fiber reinforced ceramic having all the above-mentioned features and a method for producing the same have not yet existed.

[0170]

The prepreg of the present invention is excellent in tackiness and drapability and has a long out time. Therefore, the prepreg of the present invention can be easily processed into a laminated molded article having a complicated and large shape by the same method as the epoxy resin prepreg currently widely used in practice.

The cured prepreg obtained by heat-treating the laminated molded body of the prepreg hardly undergoes a dimensional change even during the curing treatment, and its shape and the bondability between the inorganic fiber and the matrix are well maintained. . Therefore, in the cured prepreg of the present invention, peeling of inorganic fibers, surface cracks, and generation of voids are hardly observed. Moreover, the prepreg cured product of the present invention hardly changes its shape even when heated in air at a temperature of 500 ° C. or more under unconstrained conditions and under normal pressure. Further, the cured prepreg of the present invention can be made into an inorganic fiber reinforced ceramic body by heating and firing at a temperature of 1,200 ° C. or less at which the deterioration of the inorganic fiber does not occur.

According to the densification method of the present invention, the prepreg fired body, which is an inorganic fiber reinforced ceramic body, is impregnated with a composition liquid of the same type as the matrix composition and fired again to fill voids generated in the firing process. A ceramic product with further improved strength can be manufactured.

According to the present invention, an inorganic fiber reinforced ceramic body can be industrially easily produced without causing a change in shape, and 1) complicated and disadvantageous in the prior art. It is difficult to manufacture large parts. 2) Reaction occurs between the fiber and the matrix due to pressurization under high temperature and pressure, and fiber deterioration occurs.
3) It is possible to solve the technical problem that cracks or voids occur due to the difference in thermal contraction or thermal expansion between the fiber and the matrix.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C04B 35/80

Claims (18)

(57) [Claims] 1. The following components (A), (B) and (C)
A prepreg characterized by impregnating or heat-penetrating a liquid or sheet-like material of a matrix composition containing a component, a component (D) and a component (E) into a tow of inorganic fibers or a product of inorganic fibers. (A) component: fine powder of metal oxide having an average particle diameter of 1 μm or less, (B) component: soluble siloxane polymer having a double-chain structure, (C) component: at least one ethylenically unsaturated double bond.
A trifunctional silane compound contained in an individual molecule, (D) component; organic peroxide, (E) component; at least two ethylenically unsaturated double bonds.
Radical polymerizable monomer in individual molecule 2. The amount of component (A) in the matrix composition is 350 to 750 parts by weight, the amount of component (B) is 80 to 170 parts by weight, and the amount of component (C) is 25 to 1 part by weight.
The prepreg according to claim 1, wherein 25 parts by weight, the compounding amount of the component (D) is 1 to 4 parts by weight, and the compounding amount of the component (E) is 25 to 125 parts by weight. 3. The prepreg according to claim 1, wherein the component (A) is an oxide or a composite oxide containing at least one selected from silica, alumina, and titanium oxide. 4. The prepreg according to claim 1, wherein the component (B) is a polysilsesquioxane. 5. The component (B) is at least one selected from the group consisting of polyphenylsilsesquioxane, polyethylsilsesquioxane, polymethylsilsesquioxane, and a copolymer of monomers constituting these. The prepreg according to claim 4. 6. The prepreg according to claim 1, wherein the component (C) is γ- (meth) acryloxyalkyl trialkoxysilane. 7. The prepreg according to claim 1, wherein the component (D) is a peroxide whose temperature for obtaining a half life of 10 hours is 110 ° C. or higher. 8. The prepreg according to claim 1, wherein the component (E) is a polyhydric alcohol di (meth) acrylate and / or a polyhydric alcohol tri (meth) acrylate. 9. The inorganic fiber is at least selected from the group consisting of glass fibers, alumina fibers, silica fibers, Tyranno fibers, and oxide-based inorganic fibers composed of various fibers containing alumina and / or silica as a main component. The prepreg according to claim 1, which is a kind. 10. The prepreg according to claim 1, wherein the inorganic fiber product is one of a towed product and a knitted fabric. 11. The component (A) according to claim 1,
A liquid obtained by dissolving or dispersing the component (B), the component (C), the component (D) and the component (E) in a solvent is impregnated or applied to a tow of inorganic fiber or a product of inorganic fiber, and thereafter A method for producing a prepreg, comprising heating at least a part of the solvent before removing the solvent. 12. The component (A) according to claim 1,
A sheet is produced by removing a part of the solvent from a solution obtained by dissolving or dispersing the component (B), the component (C), the component (D) and the component (E) in a solvent, and forming the sheet. A method for producing a prepreg, comprising heating and infiltrating a product into an inorganic fiber product. 13. The operation of heat-penetration of the inorganic material of the sheet into the product by superimposing the sheet on one or both sides of the product of the inorganic fiber, or by combining the sheet and the inorganic fiber The method for producing a prepreg according to claim 12, wherein the products are alternately overlapped with each other and then heated and infiltrated. 14. A shaped body obtained by laminating or molding the prepreg according to claim 1 in a predetermined shape at a temperature of 12 ° C.
A prepreg cured product obtained by heating and pressurizing under the conditions of 0 to 250 ° C and a pressure of ^{2 to} 10 kg / cm ² . 15. A prepreg fired body obtained by heating the prepreg cured body according to claim 14 to a temperature between 500 and 1,200 ° C. 16. The prepreg cured product according to claim 14 in air, at normal pressure and under unconstrained conditions, from 500 to 1,
A prepreg fired body characterized by being heated to a temperature between 200 ° C. 17. Heating the prepreg cured product according to claim 14 to 500 ° C. at a heating rate of 5 ° C./min or less, and then heating to a temperature between 500 ° C. and 1,200 ° C. A method for producing a fired prepreg body. 18. The prepreg fired product according to claim 15, wherein the component (A), the component (B),
Immerse in a liquid obtained by dissolving or dispersing the component (C), the component (D) and the component (E) in a solvent, or a liquid containing at least the component (B), and
A method for densifying a prepreg fired body, comprising repeating heating to a temperature between ° C and at least once.