JP2927589B2 - Heat-resistant fiber binder, heat-resistant fiber nonwoven fabric and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder for a heat-resistant fiber which is excellent in heat resistance and adhesiveness and hardly causes migration in a non-woven fabric, and a method for producing a heat-resistant fiber non-woven fabric using the binder.

[0002]

2. Description of the Related Art Inorganic fibers such as glass fibers and ceramic fibers, and aromatic polyamides (aramids)
High-performance organic fibers represented by fibers have many excellent features such as heat resistance, non-combustibility, heat insulation, electrical insulation, chemical stability, abrasion resistance, high strength and high elasticity. ing. For this reason, attempts have been made to make these fibers into a nonwoven fabric by utilizing these characteristics.

[0003] Since most heat-resistant fibers have no self-adhesive strength, an adhesive is used for bonding between the fibers. As the adhesives proposed so far, organic substances such as cellulose and organic adhesives, and inorganic substances such as alumina sol, colloidal silica and asbestos,
Or a combination of both. However, these adhesives have the following disadvantages, respectively.
At present, sheets that fully utilize the characteristics of heat-resistant fibers have not been put on the market.

That is, a non-woven fabric made of cellulose pulp or an organic adhesive is used as a binder at 200 ° C.
Under the above-mentioned high temperatures, organic substances are decomposed, so that the strength is extremely weakened, and there is a disadvantage that the material collapses and the shape cannot be maintained. Further, binders such as alumina sol and colloidal silica are inferior in adhesion to fibers, and the obtained nonwoven fabric is liable to crack at a high temperature, and thus has insufficient strength. Therefore, when the amount of the binder is increased in order to increase the sheet strength, the flexibility becomes poor, and the range of application becomes extremely narrow. In addition, asbestos has a problem in that its carcinogenicity is problematic and its use is being restricted.

Further, according to recent studies by the present inventors, JP-A-64-77000 and JP-A-1-16285 have been disclosed.
No. 3 proposed that a hydrolyzed condensate of an alkyl silicate ester is effective as a fiber-to-fiber binder for heat-resistant fibers. However, since these binders use organic solvents such as alcohols as solvents, their practical use is difficult in terms of safety and the like when used in ordinary paper machines.

Japanese Unexamined Patent Publication (Kokai) No. 64-85369 discloses an aqueous binder containing rod-shaped colloid, trialkoxysilane, acid and water. Further, as a result of the study by the present inventors, an aqueous binder having a long pot life was obtained, and the method was proposed in Japanese Patent Application Laid-Open No. 3-124865. Furthermore, the aqueous binder is more excellent in safety than the binder containing the organic solvent. However, since all of these binders are water-based, migration of the binder occurs with movement of water during drying, and the phenomenon that the binder distribution in the nonwoven fabric is extremely deviated to one side often occurs. Was.
Such an extreme displacement of the binder adversely affects the strength of the nonwoven fabric such as tension and tear, the interlayer strength and the density distribution in the thickness direction, and the performance of this nonwoven fabric when applied to various fields is reduced. It may work negatively.

[0007]

As described above, the conventional heat-resistant fiber binder has various disadvantages, and it has been difficult to produce a heat-resistant fiber nonwoven fabric having sufficient performance. .

[0008] In the field unrelated to non-woven fabrics, silicone resin compositions are used as a binder for mica moldings used as parts of electric products such as toasters and electric irons (Japanese Patent Laid-Open No. 50-98550). No.). It focuses on the heat resistance and mechanical strength of the silicone resin. The present inventors have considered applying the adhesiveness and heat resistance of this silicone resin to a nonwoven fabric. However, this silicone resin composition is used by being applied to mica in a state of being dissolved in an organic solvent such as an isopropyl alcohol / xylene solution. Therefore, as it is, it has the same drawbacks as the binder using the above-mentioned organic solvent.

Accordingly, an object of the present invention is to provide a binder for a heat-resistant fiber which is excellent in adhesiveness and heat resistance, hardly causes migration in a nonwoven fabric, and can be used in an aqueous system.

Another object of the present invention is to provide a method for producing a nonwoven fabric of a heat resistant fiber which is excellent in heat resistance and has a high mechanical strength by uniformly dispersing a binder in the nonwoven fabric.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a binder for heat-resistant fibers, which comprises a thermosetting organopolysiloxane resin powder.

[0012]

Further, the present invention relates to a sheet obtained by mixing a mixture of a heat-resistant fiber, a thermosetting organopolysiloxane resin powder, an anionic surfactant and a cationic fixing agent, forming a slurry, and forming a sheet. Is heated to cause the above-mentioned organopolysiloxane resin to melt and polycondensate.

The binder of the present invention and a method for producing a nonwoven fabric using the binder will be described below.

Binder The binder for heat-resistant fibers of the present invention contains a thermosetting organopolysiloxane resin powder. Here, the thermosetting organopolysiloxane resin powder is solid at normal temperature,
And an organopolysiloxane resin powder that melts at 50 to 200 ° C. and undergoes polycondensation. The organopolysiloxane resin is a powder that is solid at room temperature because it is dispersed in water or an aqueous solution at room temperature and used for papermaking. The average particle size of the powder is, for example, 10 to 500 μm, preferably 10 to 200 μm.
μm is appropriate from the viewpoint of fixing the powder particles. Further, the organopolysiloxane resin used in the present invention is appropriately selected in molecular weight and the degree of three-dimensional crosslinking so as to be melted at 50 to 200 ° C., and is subjected to polycondensation. Those having a reactive functional group such as an OR (OR is an alkoxy group) group, a Si—H group, or the like are selected. For example, in a methylsilicone resin, a resin having 1.2 to 1.5 methyl groups per silicon atom generally polymerizes and cures when heated as a solid at room temperature. In the case of an ethyl silicone resin, 0.5 to 1.5 ethyl groups per silicon atom is suitable.

The above-mentioned organopolysiloxane resin is
One type of resin or a mixture of two or more types of organopolysiloxane resins may be used. Furthermore, a silicone resin modified with an alkyd resin, an acrylic resin, an epoxy resin, a polyester resin, or the like, and a mixture of the modified silicone resin with the above-described ordinary silicone resin are also included.

Further, the organopolysiloxane resin may contain a catalyst, if necessary, in order to control the rate of the polycondensation reaction. Examples of the catalyst include zinc octylate, nickel actylate, benzoyl peroxide and the like. The type and amount of the catalyst can be appropriately determined depending on conditions such as the temperature and residence time of the drying step of the nonwoven fabric (the organopolysiloxane resin is melted and polycondensed by heating).

Further, the binder of the present invention is obtained by adding an anionic surfactant to the above-mentioned organopolysiloxane resin, and further obtained by dispersing a mixture of the above-mentioned organopolysiloxane resin and a cationic surfactant in water. Can also be The anionic surfactant has effects of easily dispersing the organopolysiloxane resin in water and promoting fixation in the subsequent nonwoven fabric sheeting step. Examples of the anionic surfactant include those having a hydrophilic group of a carboxylate, a sulfate, a sulfonate, a phosphate or the like. The amount of the anionic surfactant is preferably in the range of 0.1 to 1 part by weight based on 100 parts by weight of the organopolysiloxane resin.

Further, the binder of the present invention is disclosed in
Of the silicone resin compositions disclosed in JP-A-0-98550, those which are solid at ordinary temperature, melt at 50 to 200 ° C., and undergo condensation polymerization can also be used. That is,
The organopolysiloxane resin has an average composition formula of R ¹ Si (OR ² ) _a (R ³ ) _b O _{(3-ab) / 2} (R ¹ is a monovalent organic group containing at least one epoxy group, R ² and R ³ is a substituted or unsubstituted monovalent hydrocarbon group, 0.5 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ a + b ≦
Epoxy group-containing organosilicon compound 20) represented by 3)
A mixture containing 80 parts by weight of phosphoric acid and 80 to 20 parts by weight of phosphoric acid (referred to as a phosphoric acid mixture) is also included in the binder of the present invention. The mixing ratio is, for example, 0.5 to 30 parts by weight of the phosphoric acid mixture with respect to 100 parts by weight of the organopolysiloxane resin.
It can be by weight.

The above average composition formula R ¹ Si (OR ² )
_The organosilicon compound containing an epoxy group represented by _a (R ³ ) _b O _{(3-ab) / 2} is equivalent to an organosilane or an organodisiloxane, and the organic group R ¹ has one epoxy group. It is contained above. This epoxy group is phosphoric acid (H
Reacts with ₂ PO ₄ ) to form a compound soluble in water and alcohols, and this compound has caking properties. on the other hand,
Alkoxy group represented by OR ² is a hydrolyzable group, the phosphoric acid excess or unreacted hydrolyzable becomes catalyst to polymerize cause condensation. As a result, a nonwoven fabric having excellent moisture resistance, water resistance, and mechanical strength can be provided. In the formula, R ¹ is

[0021]

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[0022]

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[0023]

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And the like. R^TwoAs -C
H_Three, -C_TwoH_Five, -C_ThreeH₇, -C_FourH ₉Can be illustrated
You. And R^ThreeIs -CH_Three, -C_TwoH_Five, -C_Three
H₇, -CH = CH_Two, -C₆H_FiveAnd the like.
A specific example of this organosilicon compound is γ-glycidoxy.
Propyltrimethoxysilane, β- (3,4-epoxy
Cyclohexyl) ethyltrimethoxysilane, ethylto
Limethoxysilane, 1-glycidoxypropyl-1,
1, 3, 3, 3-pentamethyldisiloxane
These are manufactured by a known method.

Another component, phosphoric acid (H ₂ P
O ₄ ) is most preferably a high-purity product having a low water content, but practically having a purity of 85% or more does not hinder the purpose of the present invention. As an adverse effect of this moisture, the above-mentioned general formula R ¹ Si (O
The OR ² group of the epoxy group-containing organosilane or epoxy group-containing organodisiloxane represented by R ² ) _a (R ³ ) _b O _{(3-ab) / 2} is hydrolyzed by water during the production of the binder. There is a concern that the condensation reaction may be accelerated, or the product may not be practically used as a gel during storage as a product. However, the condensation reaction can be suppressed by coexisting monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butanol. No problem.

Phosphoric acid mixture (hereinafter referred to as component (b))
Is represented by the general formula R ¹ Si (OR ² ) _a (R ³ ) _b O
_{A component represented by (3-ab) / 2} , for example, γ-glycidoxypropyltrimethoxysilane is mixed and dissolved in a monohydric alcohol such as isopropyl alcohol, and phosphoric acid is added thereto with stirring (exothermic reaction occurs). Therefore, it may be necessary to cool) and then mixed with an organopolysiloxane resin (hereinafter referred to as component (a)) prepared separately. Component (a) may be previously dissolved in a mixed solvent of toluene and isopropyl alcohol. The component (b) is prepared as described above, and it may be either a mixture obtained by mixing only (although heat is generated by mixing) or a mixture obtained by further heating and stirring after mixing. Since the component (b) is also stored for a long time, the binder of the present invention can be prepared in situ by blending it with the component (a) during actual use.

Next, the mixing ratio of each component will be described. The mixing ratio of the component (b) is 0.5 to 3 with respect to 100 parts by weight of the organopolysiloxane resin as the component (a).
0 parts by weight, preferably 2 to 20 parts by weight. This is because, if the amount of the component (b) is too small, the binding effect is good but the moisture resistance and water resistance are poor. If the amount is too large, the moisture resistance and water resistance are sufficiently exhibited, but the binding effect is poor. Become inferior.

The component (b) used in the present invention comprises 20 to 80 parts by weight, preferably 40 to 60 parts by weight, of an epoxy group-containing organosilicon compound and 80 to 20 parts by weight, preferably 60 to 40 parts by weight of phosphoric acid. Parts of the mixture (both react exothermically upon mixing). When the amount of the epoxy group-containing organosilicon compound is less than 20 parts by weight, the proportion of phosphoric acid increases, so that unreacted phosphoric acid remains, and excessively accelerates the condensation rate of the silicone resin, It tends to result in insufficient water resistance. Conversely, if the amount is more than 80 parts by weight, the proportion of phosphoric acid is too small, so that the amount of the polymerized organic silicon compound containing an epoxy group and phosphoric acid decreases, and unreacted epoxy groups are reduced. As the organosilicon compound containing remained
Also in this case, sufficient performance in terms of moisture resistance, water resistance and the like cannot be obtained. When an epoxy group-containing organosilicon compound and phosphoric acid are mixed, an exothermic reaction occurs. If necessary, this mixture may be further kept under heating for a predetermined time to complete the reaction.

The above silicone resin composition contains a large amount of solvent after preparation. Then, when this solvent is removed by a method such as drying under reduced pressure, a translucent flake-shaped solid silicone resin is obtained. This solid silicone resin is easily melted when heated to about 100 ° C., but is basically a thermosetting resin, so if the heating is continued thereafter, the polycondensation reaction proceeds and the resin is cured three-dimensionally. Then, the solid silicone resin is pulverized to an appropriate size to obtain the heat-resistant fiber binder of the present invention.

Method for Producing Nonwoven Fabric The heat resistant fiber used in the present invention is selected according to the heat resistance and properties required for the nonwoven fabric, and the type thereof is not particularly limited. For example, silica fiber (quartz fiber), high silicate fiber, glassy silica fiber, ceramic fiber (alumina
(Silica fiber), alumina fiber, kaolin fiber, bauxite fiber, zirconia fiber, potassium titanate fiber, silicon carbide whisker, metal fiber, carbon fiber, glass fiber, aromatic polyamide (aramid) fiber, polyimide fiber and the like.

In the method for producing a heat-resistant fiber nonwoven fabric according to the present invention, first, a heat-resistant fiber, a thermosetting organopolysiloxane resin powder and an anionic surfactant are dispersed in water to obtain a mixture. Preferably, a thermosetting organopolysiloxane resin powder is added to and mixed with an aqueous solution containing an anionic surfactant to hydrophilize the resin powder, and then this aqueous solution and a fiber slurry are mixed. This mixture is mixed with a cationic fixing agent to prepare an aqueous slurry. The anionic surfactant is adsorbed on the organopolysiloxane resin powder, and then the fixation to the heat-resistant nonwoven fabric is promoted by the mediation of the cationic fixing agent. The content of the heat-resistant fiber, the thermosetting organopolysiloxane resin powder, the anionic surfactant and the cationic fixing agent in the aqueous slurry depends on the heat-resistant fiber used, the thermosetting organopolysiloxane resin powder, and the anionic interface. It depends on the type of activator and cationic fixing agent.

The content of the heat-resistant fiber is 0.1 to 100 parts by weight of water from the viewpoint of good dispersibility of the fiber in water.
Suitably, it is in the range of 1 to 2 parts by weight. The content of the thermosetting organopolysiloxane resin powder is selected from the viewpoint that a nonwoven fabric having sufficient strength and flexibility is obtained.
It is appropriate that the amount is in the range of 5 to 30 parts by weight with respect to 0 parts by weight. From the viewpoint of sufficiently covering the surface of the organopolysiloxane resin and rendering it hydrophilic, the content of the anionic surfactant is preferably 0.05 to 1 part by weight based on 100 parts by weight of the organopolysiloxane resin. It is.
The content of the cationic fixing agent is 0.01 to 1 part by weight based on 100 parts by weight of the heat-resistant fiber, from the viewpoint that the organopolysiloxane resin hydrophilized by the anionic surfactant is sufficiently fixed to the heat-resistant fiber. It is appropriate to set the range of parts.

The cationic fixing agent includes, for example, cationically modified polyacrylamide, starch, polyethyleneimine, polyamide / polyamine / epixel hydrin resin and the like.

The obtained aqueous slurry is formed into a wet web by a paper machine such as a round net or a long net. The wet web can be press dewatered if necessary. Then
The obtained sheet is heated in a drying step to melt and condense the thermosetting organopolysiloxane resin in the binder. The heating conditions vary greatly depending on the type of the thermosetting organopolysiloxane resin powder, the presence or absence of a curing catalyst, etc., for example, at about 100 to 200 ° C. and 0.5 to 5 ° C.
Minutes is appropriate from the viewpoint of obtaining a nonwoven fabric having sufficient strength. By the heating, the binder melts and flows to cover the intersections between the heat-resistant fibers, and is cured by condensation polymerization, and the fibers of the heat-resistant fibers are bonded with the binder,
The heat-resistant fiber nonwoven fabric of the present invention can be obtained.

In order to prevent the binder contained therein from being re-melted by heating the obtained heat-resistant fiber nonwoven fabric, a heat amount necessary for curing the binder is given in the drying step. The amount of heat required for curing the binder can be determined as appropriate. Further, when the condition of semi-curing of the binder is selected at the outlet of the drying step and the binder is passed between the cooling nip rolls, a nonwoven fabric having a different density can be obtained.

The content of the binder in the heat-resistant nonwoven fabric is as follows:
It varies depending on the strength and heat resistance required for the heat-resistant nonwoven fabric, the type of the binder, and the like. Usually, the content of the binder is suitably 5 to 30% by weight based on the weight of the nonwoven fabric. If the content is less than 5% by weight, the strength of the nonwoven fabric is insufficient, and if it exceeds 30% by weight, the flexibility of the nonwoven fabric is lost and the nonwoven fabric is easily broken.

[0037]

As described above, the binder of the present invention can provide a heat-resistant fibrous nonwoven fabric having excellent heat resistance because the basic skeleton after curing is a siloxane bond. Moreover, although it is solid at room temperature, it is easily melted and fluidized by heating at about 100 ° C., and then thermally cured, so that it is the most suitable as a binder for nonwoven fabric. That is, since it is a solid, it can be directly introduced and mixed into the heat-resistant fiber dispersion slurry, and is melted and fluidized by heating in the drying step to cover the intersections between the fibers, and then cured.

In the case of an aqueous binder, migration of the binder generally occurs with the movement of water during drying. But,
Since the binder of the present invention is a water-insoluble particle, there is no deviation of the binder, regardless of the migration of the binder caused by movement of water.

[0039]

Next, the present invention will be described in more detail by way of examples. Components ((b) component) composed of an epoxy group-containing organosilicon compound and phosphoric acid ((b) -1) are shown below.
(B) -6 was used.

(B) -1 35 g of γ-glycidoxypropyltrimethoxysilane was dissolved in 120 g of isopropyl alcohol, and 45 g of phosphoric acid was added dropwise with stirring for 1 hour.
C. for 4 hours and cooled.

(B) -2 16 g of γ-glycidoxypropyltrimethoxysilane was dissolved in 120 g of isopropyl alcohol, and 64 g of phosphoric acid was added dropwise with stirring for 1 hour.
C. for 4 hours and cooled.

(B) -3 63 g of γ-glycidoxypropyltrimethoxysilane was dissolved in 120 g of isopropyl alcohol, and 17 g of phosphoric acid was added dropwise with stirring for 1 hour.
C. for 4 hours and cooled.

(B) -4 35 g of β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane was dissolved in 120 g of ethyl alcohol, 45 g of phosphoric acid was added dropwise with stirring for 30 minutes, and the mixture was further heated at 77 ° C. What was kept for 4 hours and cooled.

(Ii) -5 17 g of β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane was dissolved in 120 g of ethyl alcohol, and 63 g of phosphoric acid was added dropwise with stirring for 30 minutes. What was kept for 4 hours and cooled.

(B) -6 63 g of β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane was dissolved in 120 g of ethyl alcohol, and 17 g of phosphoric acid was added dropwise with stirring for 30 minutes. What was kept for 4 hours and cooled.

Example 1 As the organopolysiloxane resin (a), a resin obtained by hydrolyzing methyltrichlorosilane in the coexistence of isopropyl alcohol was used in an amount of 10% by weight.
A solution dissolved in isopropyl alcohol / xylene at a concentration was used. Compositions obtained by mixing (b) -1 to (b) -3 described above in various proportions shown in Table 1 were obtained. The solvent was removed therefrom by vacuum drying to obtain a solid silicone resin composition. This was dry-pulverized to about 100 μm pass. This silicone resin is replaced with silicone resin 10
The mixture was added and mixed with water to which 0.5 part by weight of an anionic surfactant (Kao, Atlas Perex OTP) was added to 0 part by weight to obtain a silicone resin slurry. This silicone resin slurry is added to a glass fiber dispersion slurry at a ratio of 15 parts by weight to 100 parts by weight of glass fibers.
After mixing, a silicone resin was fixed by adding 0.3 parts by weight of a chaoline-based fixing agent (Kuroda Kogyo, Crifix CP633) to 100 parts by weight of the heat-resistant fiber to obtain a papermaking raw material. Using this raw material, a glass fiber nonwoven fabric having a basis weight of 100 g / m ² was obtained using a round mesh paper machine.

The glass fiber nonwoven fabric was measured for tensile strength, strength after heating, and physical properties of binder migration, and the results are shown in Table 2. In the migration test, two hand-made sheets having the same composition and the same rice tsubo were stacked and dried with a rotary drier. After drying, the two sheets were peeled off, and the sheet tsubo of each sheet was measured.

Example 2 As the organopolysiloxane resin (a), a silicone-modified alkyd resin (trade name: SA-4, trade name:
(Shin-Etsu Chemical Co., Ltd.) dissolved in xylene at a resin content of 10% was used. The above (b) -4
To (b) -6 in various proportions shown in Table 1 to obtain compositions. The solvent was removed therefrom by vacuum drying to obtain a solid silicone resin composition. 100μ
Dry pulverization to about m passes. This silicone resin was added and mixed with water in which 0.5 part by weight of an anionic surfactant (Kao, Atlas Perex OTP) was added to 100 parts by weight of the silicone resin to obtain a silicone resin slurry. The silicone resin slurry was added to and mixed with the ceramic fiber dispersion slurry at a ratio of 15 parts by weight with respect to 100 parts by weight of the ceramic fibers, and then a chaotic fixing agent (Kuroda Kogyo, Crifix CP633) was added to the heat-resistant fiber 100. By adding 0.3 parts by weight to the parts by weight, the silicone resin was fixed to obtain a raw material for papermaking. Using this raw material, a ceramic fiber nonwoven fabric having a basis weight of 100 g / m ² was obtained by a round paper machine.

The ceramic fiber nonwoven fabric was measured for tensile strength, strength after heating, and physical properties of binder migration, and the results are shown in Table 2. In the migration test, two hand-made sheets having the same composition and the same rice tsubo were stacked and dried with a rotary drier. After drying, the two sheets were peeled off, and the sheet tsubo of each sheet was measured.

Example 3 A commercially available solid silicone resin having the same composition as the binder of the present invention (trade name: KR-220, manufactured by Shin-Etsu Chemical Co., Ltd.)
Is dry-ground to about 100 μm pass, and this silicone resin is charged and mixed with water in which 0.5 part by weight of an anionic surfactant (Kao, Atlas Perex OTP) is added to 100 parts by weight of the silicone resin, and the silicone resin slurry is added. I got The silicone resin slurry was added to and mixed with the aramid fiber dispersion slurry at a ratio of 15 parts by weight with respect to 100 parts by weight of the aramid fibers, and then a kaotin-based fixing agent (Kuroda Kogyo, Crifix CP633) was added to 100 parts by weight of the heat-resistant fiber. The silicone resin was fixed by adding 0.3 parts by weight per part, thereby obtaining a raw material for papermaking. Using this raw material, an aramid fiber nonwoven fabric having a basis weight of 100 g / m ² was obtained using a round mesh paper machine.

The tensile strength of the aramid fiber nonwoven fabric, the strength after heating, and the physical properties of the binder migration were measured.
The results are shown in Table 2. In the migration test, two hand-made sheets having the same composition and the same rice tsubo were stacked and dried with a rotary drier. After drying, the two sheets were peeled off, and the sheet tsubo of each sheet was measured.

Comparative Example 1 Except that a PVA binder (trade name KVG, manufactured by Denki Kagaku Kogyo KK) was used instead of the binder of the present invention, a basis weight of 100 g / m ² was obtained in the same manner as in Example 1. A glass fiber non-woven fabric was obtained. The physical properties are shown in Table 2.

Comparative Example 2 Glass fiber having a basis weight of 100 g / m ^{2 was} prepared in exactly the same manner as in Example 1 except that alumina sol (trade name: alumina sol, manufactured by Nissan Chemical Industries, Ltd.) was used instead of the binder of the present invention. A non-woven fabric was obtained. The physical properties are shown in Table 2.

[0054]

[Table 1]

[0055]

[Table 2]

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-126654 (JP, A) JP-A-63-209708 (JP, A) JP-T-56-500854 (JP, A)

Claims (3)

(57) [Claims] 1. A binder for a heat-resistant fiber, comprising a thermosetting organopolysiloxane resin powder. 2. The binder according to claim 1, wherein the average particle size of the thermosetting organopolysiloxane resin powder is 10 to 500 μm. 3. A mixture of a heat-resistant fiber, a thermosetting organopolysiloxane resin powder, an anionic surfactant and a cationic fixing agent is mixed, a slurry is formed, and the formed sheet is heated. A method for producing a heat-resistant fibrous nonwoven fabric, comprising melting and polycondensing a thermosetting organopolysiloxane resin in a binder.