JPH0577367A - Heat-resistant sheet excellent in bending resistance - Google Patents

Abstract

PURPOSE:To provide a heat-resistant sheet enhanced in mechanical strength, especially, bending-resistant strength, easy to sew, hard to generate the cutting of stitches and having high heat resistance and excellent bending resistance. CONSTITUTION:A heat-resistant coating layer 2 containing fluoroplastic with an m.p. of 280 deg.C or lower and 1-200 pts.wt. per 100 pts.wt. of the fluoroplastic of alkali titanate is formed to base cloth 1 composed of a heat-resistant org. synthetic fiber having an m.p. or thermal decomposition point of 300 deg.C or higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat resistant sheet having excellent bending resistance, and more specifically to a heat resistant sheet having excellent sewability and bending resistance.

[0002]

2. Description of the Related Art Conventionally, polyester fibers (having a melting point of 255 to
260 ° C, polyamide (nylon) fiber (melting point 215
To 260 ° C.), a fibrous base cloth, a thermoplastic resin,
For example, polyvinyl chloride (PVC) (heat resistant temperature 66 to 7
9 ° C), polyurethane (heat-resistant temperature 90-120 ° C), acrylic resin (heat-resistant temperature 60-88 ° C), polyethylene (heat-resistant temperature 80-120 ° C), polypropylene (heat-resistant temperature 120-160 ° C), polyamide (heat-resistant temperature 80) ~ 1
Sheet materials obtained by coating with (50 ° C.) or polyester (heat resistant temperature of about 120 ° C.) are known.

In this case, since the fibrous base cloth has a relatively low melting point, the coating material for coating the fibrous base cloth must be one that can be coated at a processing temperature that the fibrous base cloth can withstand. Therefore, as the coating material, a resin having relatively low heat resistance is used as described above. However,
Recently, fiber sheet materials have been used, for example,
Since it is often used for heat-resistant clothing, building materials, etc., in order to maintain safety from fire, burns, and other thermal disasters, demands for noncombustibility and flame retardancy are increasing. Therefore, development of heat resistant sheet material is strongly desired.

In response to the above demands, Japanese Patent Laid-Open No. 58-58
120677 and 58-127757 propose high-temperature heat-insulating paints and fire-resistant heat-insulating films containing an alkali titanate and a silicone resin, and are disclosed in JP-A-58-130183, 58-199791, and 59-35938. Discloses a fire resistant sheet obtained by forming a coating layer containing a silicone resin and an alkali titanate on the surface of an inorganic core material such as a glass base cloth or asbestos paper.

Also, Japanese Patent Laid-Open Nos. 59-26987 and 59
No. 36157 discloses a heat-resistant composition in which a polyorcanophosphonitrile compound is mixed with a silicone resin, an alkyl silicate or the like, and coating of an inorganic core material with the heat-resistant composition. Heat-resistant sheets using these inorganic fiber base fabrics have excellent fire insulation properties, antifouling properties, weather resistance, etc., but their weight (weight) is large and they are inconvenient to use and handle. In addition, since it is difficult to sew and has low bending resistance, there are problems such as easy breakage during use and tearing from perforations. Further, when a method of baking and fixing PTFE at a high temperature such as 480 ° C. is applied to the base fabric disclosed in JP-A-59-14950, in a conventional heat-resistant sheet using an organic fiber base fabric, Since the heat-resistant coating layer is formed and heat-treated at an extremely high temperature, the mechanical strength of the base fabric is lowered.

[0006]

DISCLOSURE OF THE INVENTION The present invention has satisfactory heat resistance, high mechanical strength, easy sewing,
An object of the present invention is to provide a heat-resistant sheet which has excellent bending resistance and is resistant to cutting from perforations.

[0007]

A heat-resistant sheet having excellent bending resistance according to the present invention comprises a base fabric containing as a main component a heat-resistant organic synthetic fiber having a melting point of 300 ° C. or higher or a thermal decomposition point, 28 formed on at least one side thereof and
It is characterized by comprising a fluorine-containing resin having a melting point of 0 ° C. or lower, and a heat resistant coating layer containing 1 to 200 parts by weight of alkali titanate with respect to 100 parts by weight of the fluorine-containing resin.

[0008]

The function of the heat-resistant sheet of the present invention, which is excellent in bending resistance, is
As shown in FIG. 1, it comprises a base cloth 1 containing heat-resistant organic synthetic fibers as a main component, and heat-resistant coating layers 2 formed on both surfaces thereof. The heat resistant coating layer 2 may be formed only on one surface of the base fabric 1.

The heat-resistant fibers constituting the base fabric of the heat-resistant sheet having excellent bending resistance of the present invention have a melting point of 300 ° C. or higher,
Alternatively, it is selected from organic synthetic fibers having a thermal decomposition point. Polymers forming such high melting point or high decomposition point fibers include those shown in Tables 1 and 2.

[0010]

[Table 1]

[0011]

[Table 2]

Among the heat-resistant polymers shown in Tables 1 and 2, aromatic polyamides, particularly polymetaphenylene isophthalamide and polyparaphenylene terephthalamide are common, and Teijin ( "HM-50" manufactured by K.K. Co., Ltd. can also be used. Useful aromatic polyamides such fibers are also at least 50 mole% of the following formula (I) and _{(II): - (Ar 1} -CONH) - (I) - (Ar 1 -CONH-Ar 2 -NHCO) -(II) [wherein, Ar ₁ and Ar ₂ represent a divalent aromatic group, and these may be the same or different from each other] It is preferable to have one as a main repeating unit.

In the above formulas (I) and (II), Ar ₁
And a divalent aromatic group represented by Ar ₂ have the following formula:

[0014]

[Chemical 1]

[In the above formula, A is -O-, -S-, -SO
_{-, - SO 2 -, -} CO -, - CH 2 - or -C (CH
₃ ) _2- representing] is preferred. These aromatic residues may contain an inert substituent such as a halogen, an alkyl group or a nitro group.

Generally, the aromatic polyamide has the following formula:

[0017]

[Chemical 2]

Those having a repeating unit represented by as a main component are more preferable. The base fabric formed of the aromatic polyamide fiber as described above has a small decrease in mechanical strength at the formation temperature of the fluorine-containing resin-containing coating layer having a melting point of 280 ° C. or less, and is excellent in bending resistance and heat resistance. You can get a sheet.

As the heat-resistant organic synthetic fiber, in addition to the above, fluorine-based fibers and other fibers can be used as long as they have a melting point or a decomposition point of 300 ° C. or higher.
Further, in order to promote adhesion to the heat resistant coating layer and other properties, fibers having a melting point lower than 300 ° C. or a decomposition point may be mixed in the base fabric. However, the heat resistant organic synthetic fiber is preferably contained in the base fabric in an amount of 50% by weight or more, and more preferably 60% by weight or more.

These heat-resistant organic synthetic fibers may be in any form such as short fiber spun yarn, long fiber yarn, split yarn, tape yarn, etc., and the base fabric is woven fabric,
It may be a knitted fabric, a non-woven fabric, or a composite fabric of these. However, considering the strength of the sewn portion and the bending resistance, a woven fabric or a knitted fabric is preferable as the base fabric, and a woven fabric is more preferable. In addition, as the form of the fiber, a form of long fiber (filament) which is less likely to be stretched against stress is preferable, and a plain woven fabric is preferably formed. However, there is no particular limitation on the knitting structure and its form. The heat resistant organic synthetic fiber base cloth used in the present invention is
It is useful for maintaining the mechanical strength of the resulting heat-resistant sheet having excellent bending resistance at a high level.

In the heat-resistant sheet having excellent flex resistance of the present invention, the heat-resistant coating layer has a fluorine-containing resin having a melting point of 280 ° C. or less, and 1 to 200 parts by weight based on 100 parts by weight of the fluorine-containing resin. And alkali titanate of.

The fluorine-containing resin used in the present invention is 28
Those having a melting point of 0 ° C. or lower, for example, tetrafluoroethylene-hexafluoropropylene copolymer (mp 275 ° C.), polychlorotrifluoroethylene (mp 215 ° C.), polyvinylidene fluoride (Mp 165 to 180 ° C.), polyvinyl fluoride (mp 200 to 210 ° C.), and chlorotrifluoroethylene-ethylene copolymer (mp 245).
(° C.) and the like.

A mixture of the above-mentioned fluorine-containing resin having a melting point of 280 ° C. or less and alkali titanate is particularly important for forming the heat resistant coating layer of the present invention. This formulation shows a particularly good effect when applied to a base fabric composed of heat-resistant organic synthetic fibers.

Although the above fluorine-containing resins have extremely good weather resistance, an ultraviolet absorber may be incorporated into these resins for the purpose of protecting the base cloth. Further, it goes without saying that a coloring agent or other performance-imparting agent may be added. The coating layer made of these resins may be microporous or may have open or discontinuous cells.

The alkali titanate used in the present invention has the general formula M ₂ O.nTiO ₂ .mH ₂ O (where M is L
i represents an alkali metal such as Na, K, n represents a positive real number of 8 or less, and m represents 0 or a positive real number of 4 or less. ) Is a known compound, and more specifically, Li ₄ TiO ₄ Li ₂ TiO ₃ (0 <n <1, m =
0) Alkali titanate having a salt-type structure, Na
₂ Ti ₇ O ₁₅ , K ₂ Ti ₆ O ₁₅ · K ₂ Ti ₈ O ₁₇ (n <
6, m = 0), such as an alkali titanate having a tunnel structure. Of these, the general formula K ₂ O. 6 TiO
Potassium hexatitanate and its hydrate represented by ₂ mH ₂ O (wherein m is the same as above) are preferable in that the fire resistance and heat insulating properties of the final target product are further improved.

Alkali titanate is not limited to potassium hexatitanate, but is generally a fine powdery or fibrous crystal.
Among them, the fiber length is 5 μm or more, the assect ratio is 20 or more,
In particular, a value of 100 or more brings about favorable results for improving the strength of the heat-resistant sheet of the present invention having excellent bending resistance.
In addition, fibrous potassium titanate is particularly preferable for realizing the performance of the heat resistant sheet of the present invention having excellent bending resistance, in addition to having high specific heat and excellent heat insulating performance.

Further, the coating layer of the present invention may contain a high refractive index inorganic compound or a heat absorbing inorganic compound.
High refraction inorganic compound is excellent in blocking performance against radiant heat, and the endothermic inorganic compound is heated at this contact surface when directly contacting with slag during welding or fusing, and an endothermic reaction occurs at the time of its decomposition, and the temperature of the slag is reduced. Lower. Therefore, the above-mentioned inorganic compound can prevent the coating layer of the present invention from collapsing or puncture, and can further protect the sheet substrate.

The high-refractive-index inorganic compound useful in the present invention may have a refractive index of 1.5 or more, and particularly preferably has a specific gravity of 2.8 or more. Examples thereof are as follows. There is something.

1) Dolomite (dolomite specific gravity 2.8 to 2.9, refractive index 1.50 to 1.68) Magnesite (rhodochrosite 〃 3.0 to 3.1, 〃 1.51 to 1) .72) Aragonite (〃 2.9 to 3.0, 〃 1.53 to 1.68) Abatite (apatite 〃 3.1 to 3.2, 〃 1.53 to 1.54) Spinel (pinnacle 〃 3.5 to 3.6, 〃 1.72 to 1.73) Corundum (〃 3.9 to 4.0, 〃 1.76 to 1.77) Zircon (〃 3.90 to 4.10, 〃 1 .79 to 1.81) Powder of a crushed product of natural or synthetic minerals such as silicon carbide (3.17 to 3.19, 2.65 to 2.69).

2) Frit, high refraction glass, or crushed powder of fused phosphate fertilizer or other similar solid solution obtained as a solid solution of phosphate rock and serpentine, or granular material, fibrous material, foam, etc. ..

As the endothermic inorganic compound, calcined gypsum,
Alum, calcium carbonate, aluminum hydroxide, hydrosalcite type aluminum silicate, etc.
Examples thereof include endothermic inorganic compounds such as carbon dioxide releasing type, decomposition endothermic type and phase inversion type.

When a fibrous alkali titanate and, if necessary, a high refractive index inorganic compound and / or an endothermic inorganic compound are mixed and dispersed in a fluorine-containing resin, a heat resistant sheet excellent in bending resistance according to the present invention is obtained. A coating mixture for production is obtained. As a method for preparing the mixed dispersion, any known means can be used. In addition, in the coating mixture, a dispersant or a defoaming agent for uniformly dispersing each component, a colorant for adjusting color or mechanical strength, a resin powder, a flame retardant,
Metal powder and other various fillers can be freely mixed. In addition, mixing of metal powder such as copper powder, nickel powder, brass powder, and aluminum powder is preferable from the viewpoint of improving surface heat, reflection effect, and penetration suppressing effect.

As a method for coating the surface of the base cloth with the above-mentioned coating layer, the surface of the base cloth is spray-coated with a coating mixture,
A method such as brush coating, roll coating, or the like, or a method of applying a film obtained by molding the coating mixture onto the surface of the base cloth, or a method of immersing the base cloth in the coating mixture and impregnating the base cloth, etc. is there.

The heat-resistant sheet of the present invention having excellent bending resistance is manufactured, for example, as follows. That is, after appropriately adding a curing accelerator and an additive to a mixture of a fluorine-containing resin, an alkali titanate and optionally a high refractive index inorganic compound, and / or an endothermic inorganic compound, toluene, xylene, trichlene are further added if necessary. An organic solvent such as the above is added to prepare a dispersion having an appropriate concentration, and the dispersion is formed by a well-known coating means such as dipping, spraying, roll coating, reverse roll coating, knife coating, etc. Apply to one or both sides of the cloth, at room temperature or under heating, preferably 15
By heat-treating in the range of 0 to 350 ° C. for 1 to 30 minutes, it is integrally fixed to the above-mentioned base material.

In particular, since the fluorine-containing resin has a melting point of 280 ° C. or lower, the heat treatment temperature can be set relatively low, so that the heat-resistant organic synthetic fiber is less strongly deteriorated and the resulting heat-resistant sheet is resistant to bending. It can give excellent results for improvement.

The mixing ratio of the fluorine-containing resin, the alkali titanate, the high-refractive-index inorganic compound, and / or the endothermic inorganic compound varies depending on the type and particle size of the fluorine-containing resin and the inorganic compound to be used. If the amount is too small, the strength of the coating layer is insufficient, resulting in defects such as cracking of the coating layer when the obtained heat resistant sheet is used as a fireproof heat insulating sheet, or peeling of the coating layer from the base fabric. On the contrary, if the amount of the fluorine-containing resin is too much, the heat resistance is lowered, and if it is remarkable, flammable combustion may occur.

Therefore, in the present invention, the fluorine-containing resin 100
The amount of alkali titanate blended with respect to parts by weight (hereinafter abbreviated as parts by weight) is 1 to 200 parts, preferably 30 parts.
It is 4 to 100 parts, and when a high refractive index inorganic compound, and / or an endothermic inorganic compound is further added to these
It can be blended by replacing it with alkali titanate corresponding to the same weight to 1/4 weight up to a limit of 00 parts, but the range of 10 to 300 parts is usually preferable. Incidentally, these high-refractive-index inorganic compounds, some or all of the endothermic inorganic compounds are commonly used inorganic pigments, inorganic fillers for increasing the amount, it is possible to replace the inorganic powder to impart flame retardancy, The amount used is preferably 400 parts or less, and more preferably 300 parts or less, relative to 100 parts of the fluorine-containing resin.

The thickness of the heat-resistant sheet of the present invention having excellent bending resistance is preferably 0.02 mm or more, 0.0
More preferably, it is in the range of 5 to 2.0 mm.

An adhesive substance may be interposed between the base cloth and the coating layer for the purpose of improving the adhesion and durability.
In this case, it is not necessary to intervene particularly thickly in order to improve the adhesive strength. The adhesive substance is not used for forming a film, and therefore a substance known as an adhesive can be used. For example, amino group, imino group, ethyleneimine residue, acrylate containing alkylenediamine residue, acrylate containing aziridinyl group, aminoester-modified vinyl polymer, aromatic epoxy adhesive, amino nitrogen-containing methacrylate polymer, and others. You may use an adhesive together. In addition, resins such as polyamide-imide and polyimide, which are of the same quality as the polymer constituting the fiber base cloth, and RF
It is also possible to arbitrarily select an L-modified substance or the like.

In the heat-resistant sheet having excellent flex resistance of the present invention, the heat-resistant coating layer may be formed on only one side, but it is formed on both sides to compensate for the low weather resistance of the base fabric. Depending on the usage conditions, double-sided formation may be an essential condition. On the other side, depending on the performance required for the sheet, natural rubber, neoprene rubber, chloroprene rubber, silicone rubber, hypalon, other synthetic rubber, or PVC resin, ethylene-vinyl acetate copolymer (EVA) resin, acrylic Resins, silicone resins, urethane resins, polyester resins, and other synthetic resins can also be used. In this case, it is more preferable that these resins are flame-retarded.

The thickness of the heat-resistant coating layer is preferably 5 to 2000 μm, more preferably 10 to 1500 μm.

The heat-resistant sheet having excellent bending resistance of the present invention may be formed in a tape shape, or a sheet material may be cut into a tape shape. Such a tape-shaped heat-resistant sheet can be used by being coated or wound in applications requiring heat resistance and flame retardancy such as electric wires and cables.

[0043]

EXAMPLES The heat resistant sheet having excellent flex resistance of the present invention will be described in more detail with reference to Examples.

Example 1 and Comparative Example 1 In Example 1, as a base fabric, an aromatic polyamide fiber (trademark: Conex, manufactured by Teijin Ltd.) spun yarn fabric having the following structure was used. Texture: plain weave Warp: 30 S / l, 60 threads / 25.4 mm Weft: 30 S / l, 54 threads / 25.4 mm Weight: 90 g / m ² Tensile strength (average in both warp and weft directions): 66 kg / 3 cm

As a coating composition, FEP (tetrafluoroethylene-hexafluoropropylene copolymer (m.
p.275 ° C)) 60% by weight of potassium titanate (trademark: Tismo D, manufactured by Otsuka Chemical Co., Ltd.) is mixed with 100 parts by weight of 50% aqueous dispersion, and a small amount of water-soluble acrylic resin (thickener) is added thereto. Thus, a coating liquid having a viscosity of 1200 cps was prepared.

The above base fabric was dipped in the above composition, squeezed, dried at a temperature of 250 ° C., and then melted at a temperature of up to 350 ° C. to form a film. The thickness of the obtained heat resistant coating layer was about 150 μm on both surfaces.

In Comparative Example 1, the same operation as above was repeated. However, potassium titanate was not used.

The obtained sheet was prepared according to Japanese Patent Laid-Open No. 58-1301.
It was subjected to the fireproof heat insulation test described in No. 83. At this time, the evaluation criteria of the fire resistance and heat insulation were as follows. Type A: When melting a 9 mm-thick steel plate for spark generation, there should be no through holes that are harmful to the sparks generated and fire protection. Class B: When a 4.5 mm thick steel plate for spark generation is melt-cut, there should be no through holes that are harmful to the spark generated and fire. Class C: There should be no through-holes that are harmful to the spark and fire for the spark generated when the 3.2 mm thick steel plate for spark generation is fused. Class D: When melting a 3.2 mm thick steel plate for spark generation, a through hole harmful for fire prevention was generated. Class E: Flame generated when the 3.2 mm thick steel plate for spark generation was blown.

The heat resistance and heat resistance of the heat resistant sheet of Example 1 was B.
The heat resistance of the sheet of Comparative Example 1 was D type. Further, that of commercially available asbestos paper (3A grade) was Class E. That is, the heat-resistant sheet of the present invention having excellent bending resistance showed extremely excellent fire insulation.

In addition, the heat-resistant sheet of the first embodiment is JIS
P 8115 (1976), "Folding strength test method for MIT type tester for paper and board", showed no infinite bending strength even after 10,000 bending.

Comparative Example 2 A heat resistant sheet was prepared in the same manner as in Example 1. However,
A glass fiber cloth having the following structure was used as the base cloth. Texture: Turkish satin weft Warp: DE 150 1/2 3.3S, 51 threads / 25.4 mm Weft thread: same as above, 51 threads / 25.4 mm Weight: 290 g / m ²

[0052] Further, as a coating composition, the following composition: INGREDIENT AMOUNT (parts by weight) tetrafluoroethylene - 50% aqueous dispersion a water-soluble acrylic resin of hexafluoropropylene 100 copolymer (FEP) (thickener) A mixture of 0.65 potassium titanate (trademark: Tismo D, manufactured by Otsuka Chemical Co., Ltd.) 60 was prepared. The viscosity of this mixture was about 900 centipoise.

The heat resistance of the obtained heat resistant sheet was Class A, but the folding strength was 1,000 to 2,000.
It was 0 times, which was extremely unsatisfactory.

Example 3 A heat resistant sheet was prepared in the same manner as in Example 1. However,
The spun yarn used for the base fabric was a mixed yarn (30S) of 50% by weight of Conex fiber and 50% by weight of polyethylene terephthalate fiber. The heat-resistant heat resistance of the obtained heat-resistant sheet was Class C, and the folding endurance was such that it could endure 10,000 bending cycles or more.

[0055]

INDUSTRIAL APPLICABILITY The heat-resistant sheet having excellent bending resistance of the present invention uses, as a base cloth, a cloth made of a heat-resistant organic synthetic fiber having a melting point of 300 ° C. or higher or a thermal decomposition point, and has a heat-resistant coating. The layer is made of a fluorine-containing resin having a melting point of 280 ° C. or lower, and 1 to 2 is added to 100 parts by weight of the fluorine-containing resin.
By forming it together with 00 parts by weight of alkali titanate, it has extremely excellent fire resistance and heat resistance and folding strength. Therefore, the heat-resistant sheet having excellent flex resistance of the present invention is used at high temperatures where it is repeatedly bent and violently vibrates or flicks (for example, fireproof clothing, opening / closing curtain).
Can be suitably used for.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of one embodiment of a heat-resistant sheet having excellent bending resistance of the present invention.

[Explanation of symbols]

 1 ... Base cloth 2 ... Heat resistant coating layer

Claims (4)

[Claims] 1. A base fabric containing, as a main component, a heat-resistant organic synthetic fiber having a melting point of 300 ° C. or higher, or a thermal decomposition point, and fluorine having a melting point of 280 ° C. or lower formed on at least one surface thereof. A heat-resistant sheet having excellent flex resistance, comprising a resin containing and a heat-resistant coating layer containing 1 to 200 parts by weight of alkali titanate with respect to 100 parts by weight of the fluorine-containing resin. 2. The heat resistant sheet having excellent flex resistance according to claim 1, wherein the heat resistant organic synthetic fiber is an aromatic polyamide fiber. 3. The fluorine-containing resin is selected from tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, and chlorotrifluoroethylene-ethylene copolymer. The heat resistant sheet having excellent flex resistance according to claim 1, which comprises at least one of the following: 4. The heat resistant sheet having excellent flex resistance according to claim 1, wherein the alkali titanate is potassium hexatitanate or a hydrate thereof.