JPH05131586A - Heat resisting sheet - Google Patents

Abstract

PURPOSE:To obtain a heat resisting sheet excellent in heat resistance and flexibility by impregnating at least two fiber sheets consisting of organic and/or inorganic fiber sheet with a mixture comprising clay mineral, an inorganic powder and an adhesive agent. CONSTITUTION:The heat resisting sheet for use in heat resisting tape, wall paper, dunnage material in ceramic industry, etc., is formed by impregnating at least two fiber sheets consisting of organic and/or inorganic fiber sheet with at least a mixture capable of forming film and comprising clay mineral, an inorganic powder and an adhesive agent and laminating these two sheets into a sheet having a thickness of at most 0.5mm. Silica-alumina fiber and glass fiber are used in the inorganic fiber and polyamide fiber and polyvinyl alcohol fiber are used in the organic fiber. As for the clay mineral, sepiolite, montmorillonite and smeclite are used. As to the inorganic powder, magnesium hydroxide and spinel are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet having excellent heat resistance and flexibility, which sheet can be used as a heat resistant tape, wallpaper, ceramic underlayment material and the like.

[0002]

2. Description of the Related Art Conventionally, heat-resistant sheets obtained by mixing inorganic fibers, inorganic adhesives, and inorganic powders by a wet method have been known. Although this heat-resistant sheet is excellent in heat resistance, since it is not flexible, it does not fit into a curved surface or the like, and if it is forcibly bent, cracks occur, or inorganic powder or the like separates,
It was limited in use.

Further, JP-A-55-98955 discloses a flame-retardant non-woven fabric comprising a plurality of non-woven fabric layers and substantially containing a flame retardant in the intermediate layer. Since this flame-retardant non-woven fabric contains a flame retardant in the intermediate layer, it does not cause cracking or detachment of the flame retardant when bent, but it has flame resistance but does not have heat resistance and the intermediate layer Since only the flame retardant layer, the heat resistance was insufficient.

On the other hand, Japanese Patent Application Laid-Open No. 56-109881 discloses an inorganic noncombustible molded article obtained by coating a substrate with a slurry mixture containing an inorganic film forming agent and a curing agent. However, since the inorganic film forming agent used for this inorganic non-combustible molded body is not flexible, it has not been sufficiently flexible.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has heat resistance,
It is an object to provide a heat resistant sheet having excellent flexibility.

[0006]

The present invention comprises at least two organic fiber sheets and / or inorganic fiber sheets.
It is a heat-resistant sheet in which a single fibrous sheet is substantially impregnated with a mixture of at least a clay mineral having a film-forming ability, an inorganic powder and an adhesive, and has a thickness of 0.5 mm or less.

[0007]

The heat-resistant sheet of the present invention is excellent in heat resistance because it contains clay mineral and inorganic powder.
Since the mixture containing the inorganic powder is substantially impregnated, the heat resistance of the entire heat resistant sheet is excellent.

The heat-resistant sheet of the present invention has a thickness of 0.
Since it is as thin as 5 mm or less, it has excellent flexibility, and since a clay mineral having a film forming ability is used, the flexibility is not impaired by using the clay mineral. That is, the clay mineral having a film-forming ability has a large ability to coat the inorganic powder and the fiber, the amount of the clay mineral used is small, and the clay mineral does not become brittle after drying, so that the flexibility is not impaired.

Since the fibrous sheet of the present invention holds a mixture of clay minerals, inorganic powders, adhesives, etc., it is preferably porous to some extent, and paper, non-woven fabric, woven fabric or knitted fabric is used. Is preferred. These fiber sheets 1
If one sheet is impregnated with a mixture of clay minerals, inorganic powder, adhesive, etc., the impregnated side tends to be biased and it is difficult to uniformly impregnate it.Therefore, by stacking another fiber sheet on the impregnated side, the capillary effect is obtained. Works and can be uniformly impregnated. Therefore, use two or more fiber sheets,
If the inorganic fiber is used for the fiber sheet, the shape retention at high temperature is excellent, and if the organic fiber is used, the shape retention at room temperature is excellent. It is preferable to use one or more fiber sheets made of an inorganic fiber and one fiber sheet made of an organic fiber so that the shape retention is excellent at both high temperature and normal temperature.

Examples of the inorganic fibers that can be used in the present invention include silica-alumina fibers, glass fibers, alumina fibers, silica fibers, carbon fibers, silicon carbide fibers, rock wool and metal fibers, but are not limited thereto. Not a thing.

On the other hand, as the organic fiber, a polyamide fiber,
Polyvinyl alcohol fiber, polyvinylidene chloride fiber, polyvinyl chloride fiber, polyester fiber, polyacrylonitrile fiber, polyethylene fiber, polypropylene fiber, polyurethane fiber, meta type, para type aromatic fiber, polyamideimide Examples thereof include fibers, polytetrafluoroethylene fibers, aromatic polyetheramide fibers, and polybenzimidazole fibers, but are not limited to these.

The heat-resistant sheet of the present invention has a thickness of 0.1.
The thickness of each fibrous sheet is less than 0.5 mm because the thickness is 5 mm or less to provide flexibility.

A mixture containing at least a film-forming clay mineral (hereinafter referred to as clay mineral), an inorganic powder and an adhesive is substantially impregnated into these fiber sheets.

The clay mineral of the present invention not only imparts heat resistance to the fiber sheet, but also has a large ability to coat the inorganic powder and fibers, has a binding force even in a small amount, and does not become brittle even when dried, so that it is flexible. A heat resistant sheet can be obtained. Further, since the clay mineral particles are fine fibrous, the formed film has flexibility and does not impair the flexibility. Further, by retaining water, plasticity is generated, and since the inorganic powder is uniformly dispersed, a sheet having uniform heat resistance can be obtained. Examples of this clay mineral include sepiolite, montmorillonite, hectorite, smectite, expansive fluoromica, kibushi clay, leech eye clay, and among these, smectite and expansive fluoromica are flexible films themselves. It has excellent properties and can be suitably used.

The inorganic powder of the present invention is used for imparting heat resistance to a heat resistant sheet, and when the inorganic powder having a particle size of 150 μm or less, more preferably 10 μm or less is used, it can be dispersed uniformly and densely, Excellent retention with clay minerals and adhesives. As the inorganic powder, magnesium hydroxide, spinel, lithia, forsterite, spodumene, eucryptite, steatite,
Sillimanite, aluminum titanate, agate stone, feldspar,
Magnesia, diatomaceous earth, silica, silica alumina, mullite, alumina, aluminum hydroxide, zircon, zirconia, titanium oxide, magnesia oxide, calcium oxide, calcium silicate, magnesium silicate, shirasu,
Shirasu balloon, glass, glass balloon, dolomite, kaolin, chamotte, mica, cordierite, silicon nitride, boron nitride, sepiolite, attapulgite, bentonite, hectorite, montmorillonite,
Examples thereof include, but are not limited to, synthetic fluoromica, silicon carbide, boron carbide, metal-based powder, and carbon-based powder. Among these inorganic powders, hydroxide has a flame-retardant effect due to high-temperature dehydration, and thus can be preferably used.

The adhesive of the present invention is used not only for auxiliary adhesion of an inorganic powder or the like, but also for supplementing the water resistance and strength lacking in clay minerals. This adhesive may be an organic adhesive or an inorganic adhesive, but the inorganic adhesive has excellent heat resistance, and the organic adhesive has excellent flexibility at room temperature. Therefore, it is more preferable to use both adhesives together. As organic adhesives, vinyl acetate polymers and copolymers, acrylic adhesives, ethylene copolymers, polyamides, polyesters, polyurethanes, amino resins, urea resins, melamine resins, phenolic resins, epoxy resins, Examples include rubber adhesives, and examples of inorganic adhesives include silica sol, alumina sol, zirconia sol, silicates, phosphates, or cements such as alumina cement, magnesia cement, zirconia cement. However, the present invention is not limited to these.

The clay mineral, the inorganic powder and the adhesive as described above are mixed, and the mixing ratio is 3 to 30:50 to 90: 3.
When it is -40, the heat resistance mainly due to the inorganic powder is sufficient, the bondability due to the clay mineral and the adhesive is excellent, and the heat resistant sheet which does not impair the flexibility can be obtained. In addition,
Other than these, it is also possible to mix other substances such as flame retardants within a range that does not impair heat resistance, bondability and flexibility.

Further, although it depends on the degree of porosity of the fiber sheet, since the state of impregnation into the fiber sheet differs depending on the viscosity of the mixture, the viscosity of the mixture is 100 cps or more and 5,000 c
It is preferably adjusted to ps or less. Above 5,000 cps,
Difficult to impregnate, easy to form a mixture layer between fiber sheets,
If it is less than 100 cps, it may pass through the fiber sheet to form a mixture layer on the surface of the fiber sheet, and may crack, peel, or fall off.

A fiber sheet is substantially impregnated with the mixture of the clay mineral, the inorganic powder and the adhesive. This substantially impregnation means
Filling almost the entire area in the thickness direction of the fiber sheet,
Alternatively, since it is attached to the intersections of the fibers, the entire sheet has excellent heat resistance. Note that when the amount of the mixture is too large, a layer formed by the mixture is formed between the fiber sheets or on the surface of the fiber sheet, and cracks or peeling occurs in the mixture layer,
There is a possibility that they will fall off, and the heat resistance will be poor unless the mixture is sufficiently impregnated, so it is necessary to adjust the amount of the mixture so that it is in a substantially impregnated state. The amount of this mixture varies depending on the fiber sheet, but is 50 g / m ² or more from the viewpoint of heat resistance, for example, with respect to the basis weight of 40 g / m ^{2 of} only the fiber sheet,
It is more preferably 80 g / m ² or more, and preferably 300 g / m ² or less so as not to form a layer of the mixture alone.

This impregnation method is not particularly limited, but the mixture is applied to the fiber sheet by spraying or using a coater such as a roll coater, a knife coater, or a curtain coater, and then the other is applied on the applied fiber sheet. The heat resistant sheet of the present invention can be obtained by laminating and drying the fibrous sheet. By laminating another fiber sheet, the mixture is impregnated into the other fiber sheet by the capillary effect. In addition, it is more preferable that the mixture is applied, laminated and then pressure is applied so that the mixture is spread over the entire laminated fiber sheet. When three or more sheets are laminated, the same procedure may be repeated for each layer, or after the mixture is applied to one or more fiber sheets, one or more other fiber sheets are laminated. Is also good.

The heat-resistant sheet thus obtained has a thickness of 0.5 mm or less. If the thickness of this sheet exceeds 0.5 mm, the flexibility becomes poor and the object of the present invention cannot be achieved. On the other hand, if the thickness of the heat resistant sheet is 0.1 mm or less, the amount of the inorganic powder and clay mineral that are substantially impregnated in the fiber sheet will be small and the heat resistance will be poor. It is preferably 0.1 to 0.5 mm.

As described above, since the heat-resistant sheet of the present invention has excellent heat resistance and flexibility, it can be used not only in a flat place requiring heat resistance but also in a curved place. can do. In addition, for example, a heat-resistant silicone adhesive is applied to a heat-resistant sheet and cut to form a heat-resistant tape, or the surface of the heat-resistant sheet is printed to be used as a wallpaper, or the heat-resistant sheet is further coated. If a corrugation process is performed after the calcium chloride aqueous solution is included, it can be used as a cylindrical dehumidifier.

Examples of the present invention will be described below, but the invention is not limited to the following examples.

[0024]

【Example】

(Example 1) Polyester fiber (3 denier, fiber length 6)
mm) 100% by a wet papermaking method to obtain a fiber sheet having a basis weight of 20 g / m ² and a thickness of 0.07 mm. On the other hand, 100% of glass fiber (fiber diameter 9 μm, fiber length 13 mm) was obtained by a wet papermaking method to obtain a fiber sheet having a basis weight of 15 g / m ² and a thickness of 0.12 mm.

On a fiber sheet made of this polyester, a mixture of 10 parts of expansive fluoromica having a viscosity of 2,000 cps, 20 parts of silica sol, 60 parts of aluminum hydroxide (particle size 1 μm), and 10 parts of acrylic binder was applied by a roll coater. A solid content of 125 g / m ^{2 was} applied, a fiber sheet made of glass fiber was laminated thereon, and dried at 170 ° C. for 3 minutes to obtain a heat resistant sheet having a thickness of 0.20 mm. This heat resistant sheet could be wound around a pipe having a diameter of 10 mm.
The tensile strength after leaving it in a heating furnace at 600 ° C. for 1 hour was 800 g / 25 mm width.

(Example 2) As the fiber sheet, two fiber sheets made of the same polyester as in Example 1 were used,
A heat-resistant sheet having a thickness of 0.17 mm was obtained in the same manner as in Example 1 except that the coating amount of the same mixture as in Example 1 was 120 g / m ² . This heat resistant sheet could be wound around a pipe having a diameter of 10 mm or less. Further, the tensile strength after standing in a heating furnace at 600 ° C. for 1 hour was 100 g / 25 mm width.

(Example 3) 100% polyester fiber (3 denier, fiber length 6 mm) was obtained by a wet papermaking method to obtain a fiber sheet having a basis weight of 30 g / m ² and a thickness of 0.1 mm. On the other hand, 100% of glass fiber (fiber diameter 9 μm, fiber length 13 mm) was wet-processed to obtain a fiber sheet having a basis weight of 35 g / m ² and a thickness of 0.3 mm. On the fiber sheet made of this polyester, the same mixture as in Example 1 was added in a solid content of 25.
0 g / m ^{2 was} coated, a fiber sheet made of glass fiber was laminated thereon, and dried at 170 ° C. for 3 minutes to be integrated. The resulting heat resistant sheet had a thickness of 0.40 mm. This heat resistant sheet could be wound around a pipe having a diameter of 20 mm.
Further, the tensile strength after standing in a heating furnace at 600 ° C. for 1 hour was 2000 g / 25 mm width.

Example 4 The same mixture as in Example 1 was coated on a fiber sheet made of the same polyester as in Example 1 in the same manner as in Example 1 with a solid content of 200 g / m ^{2 and then} applied as in Example 1. The laminated sheet of the fiber sheet made of glass fiber and the fiber sheet made of polyester was laminated so as to sandwich the fiber sheet made of glass fiber, and dried at 170 ° C. for 3 minutes to be integrated. The obtained heat resistant sheet had a thickness of 0.28 mm. This heat resistant sheet could be wound around a pipe having a diameter of 10 mm. Further, the tensile strength after standing in a heating furnace at 600 ° C. for 1 hour was 1000 g / 25 mm width.

Comparative Example 1 5 parts of polyvinyl alcohol powder was used in place of the expandable fluoromica in the mixture of Example 1,
A heat-resistant sheet having a thickness of 0.20 mm was obtained in the same manner as in Example 1 except that the amount of silica sol was changed to 40 parts. This heat resistant sheet was cracked when wound around a pipe having a diameter of 20 mm. Further, the tensile strength after standing in a heating furnace at 600 ° C. for 1 hour was 800 g / 25 mm width, and although it did not fall off, it was cracked.

(Comparative Example 2) The coating amount of the mixture was 400 g / m ^2.
The thickness is 0.6 mm in exactly the same manner as in Example 1 except that
A heat resistant sheet of was obtained. This heat resistant sheet has a diameter of 20 mm
When it was wound around the pipe of No. 3, cracking and delamination occurred between the two layers. Further, the tensile strength after standing in a heating furnace at 600 ° C. for 1 hour was 700 g / 25 mm width, and it was also cracked.

[0031]

Since the heat-resistant sheet of the present invention is substantially impregnated with the mixture containing the clay mineral, the inorganic powder and the adhesive, the heat-resistant sheet as a whole has excellent heat resistance.

Since the heat-resistant sheet of the present invention has a thickness of 0.5 mm or less and is thin, it is excellent in flexibility and has a film-forming ability. The clay mineral has a large ability to coat inorganic powders and fibers.
The amount of clay mineral used is small, and since it does not become brittle even after drying, flexibility is not impaired.

When one or more fiber sheets made of inorganic fibers and one fiber sheet made of organic fibers are used in the fiber sheet of the present invention, the shape retention property is excellent at both normal temperature and high temperature.

Claims (1)

[Claims] 1. At least two fibrous sheets consisting of an organic fibrous sheet and / or an inorganic fibrous sheet are substantially impregnated with a mixture of at least a film-forming clay mineral, an inorganic powder and an adhesive to obtain a thickness. A heat-resistant sheet characterized by being integrated to 0.5 mm or less.