JPH0737125B2 - Heat resistant sheet with excellent bending resistance - Google Patents

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 ℃, 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, in firefighter clothing,
Increasingly used in heat resistant clothing, film materials for building materials,
In order to maintain safety from fires, burns, and other thermal disasters, demands for non-combustibility 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-
120677 and JP-A-58-127757 propose high-temperature heat-insulating paints and fire-resistant heat-insulating films containing alkali titanate and silicone resin, and JP-A-58-130183 and 58- 1
No. 99791 and JP-A-59-35938,
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 is disclosed.

Further, JP-A-59-26987 and JP-A-59-36157 disclose a heat-resistant composition in which a polyorcanophosphonitrile compound is mixed with a silicone resin or an alkyl silicate, and this heat-resistant composition. Discloses coating an inorganic core material. Heat-resistant sheets using these inorganic fiber base fabrics have excellent fire and heat insulating 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, it is easily broken during use and is easily torn from perforations. Further, when the method of baking and fixing PTFE to a base cloth disclosed in JP-A-59-14950 at a high temperature such as 480 ° C. is applied, in a conventional heat resistant sheet using an organic fiber base cloth, Since the formation and heat treatment temperatures of the heat resistant coating layer are extremely high, 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 tearing from perforations.

[0007]

A heat-resistant sheet having excellent bending resistance according to the present invention comprises a base cloth containing 50% by weight or more of a heat-resistant organic synthetic fiber having a melting point of 300 ° C. or higher or a thermal decomposition point. , Formed on at least one side thereof, 280
A fluorine-containing resin having a melting point of ℃ or less, and a heat-resistant coating layer containing 1 to 200 parts by weight of alkali titanate to 100 parts by weight of the fluorine-containing resin and fixed at a temperature of 350 ° C. or less. It is what

[0008]

The function of the heat-resistant sheet of the present invention is excellent in bending resistance.
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 other than the above-mentioned para-aramid fibers, 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 preferred to have the species as the 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₋ ]] 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 forming temperature of the fluorine-containing resin-containing coating layer having a melting point of 280 ° C. or lower (350 ° C. or lower).
In the above, a heat-resistant sheet having a small decrease in mechanical strength and excellent in bending resistance can be obtained.

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 thermal decomposition point of 300 ° C. or higher. Fibers having a melting point lower than 300 ° C. or a thermal decomposition point may be mixed in the base fabric in order to promote adhesion with the heat resistant coating layer and other properties. However, the heat resistant organic synthetic fiber is contained in the base cloth in an amount of 50% by weight or more, and preferably 60% by weight or more.

These heat-resistant organic synthetic fibers may be of any shape 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) having a small elongation 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 (mp275 ° C.), polychlorotrifluoroethylene (mp215 ° C.), polyvinylidene fluoride (mp
165-180 ° C), polyvinyl fluoride (mp2
00 to 210 ° C.) and at least one selected from 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 lower 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 colorant or other performance-imparting agent may be added. The heat resistant 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 a positive real number of 0 or 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) and is 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 (m in the formula 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, and 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 particular, 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 heat resistant 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 shielding performance against radiant heat, and the endothermic inorganic compound is heated at this contact surface when directly contacting with slag at the time of welding or fusing, 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 heat-resistant 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 (rhodochroite 〃 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 phosphorus 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 heat-resistant coating mixture for production is obtained. As a method for preparing the mixed dispersion, any known means can be used. In addition, in the heat-resistant coating mixture, a dispersant or defoaming agent for uniformly dispersing each component, a colorant for adjusting the color or mechanical strength, a resin powder, a flame retardant, a metal powder, Other various fillers can be mixed freely. Mixing of metal powder such as copper powder, nickel powder, brass powder, and aluminum powder is preferable from the viewpoint of improving the surface heat reflection effect and the penetration suppressing effect.

The surface of the base cloth is coated with the heat resistant coating layer by spray coating, brush coating, roll coating or the like with the heat resistant coating mixture on the surface of the base cloth,
Alternatively, there is a method in which a film obtained by molding the heat-resistant coating mixture is attached to the surface of the base cloth, or a method in which the base cloth is immersed in the heat-resistant coating mixture and impregnated.

The heat-resistant sheet of the present invention having excellent bending resistance is manufactured, for example, as follows. That is, after appropriately adding a reaction 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 a dipping method, a spraying method, a roll coating method, a reverse roll coating method, or a knife coating method. Apply on one or both sides of the cloth and heat at room temperature or 350 ℃ or less,
Preferably, heat treatment is carried out within the range of 250 to 350 ° C. for 1 to 30 minutes to integrally fix the above-mentioned base material.

In particular, since the melting point of the fluorine-containing resin is 280 ° C. or less, the heat treatment temperature can be set to a relatively low value, so that the heat-resistant organic synthetic fiber is less strongly deteriorated and the resulting heat-resistant sheet has bending resistance. 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 used, but generally the fluorine-containing resin is used. Is too small as a result of insufficient strength of the heat-resistant coating layer, when the resulting heat-resistant sheet is used as a fire-resistant heat-insulating sheet, cracks occur in the heat-resistant coating layer, or the heat-resistant coating layer peels from the base cloth, etc. If a drawback is caused and conversely the amount of the fluorine-containing resin is too large, the heat resistance is lowered.

Therefore, in the present invention, the fluorine-containing resin 100
The amount of alkali titanate blended with respect to 1 part by weight is 1 to
200 parts by weight, preferably 30 to 100 parts by weight,
Furthermore, when a high refractive index inorganic compound, and / or an endothermic inorganic compound is added to these, the amount is 400 parts by weight,
It can be blended by substituting the same weight to 1/4 weight for an equivalent alkali titanate, but usually a range of 10 to 300 parts by weight is preferable. Incidentally, these high refractive index inorganic compounds,
Part or all of the endothermic inorganic compound can be replaced with commonly used inorganic pigments, inorganic fillers for increasing the amount, inorganic powders imparting flame retardancy, etc., but the amount used is 100 weight% of fluorine-containing resin. The amount is preferably 400 parts by weight or less, and more preferably 300 parts by weight or less.

The thickness of the heat-resistant sheet having excellent flex resistance of the present invention is preferably 0.02 mm or more, and 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 heat-resistant 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, other You may use an adhesive together. Further, resins such as polyamide-imide and polyimide, which have the same quality as the polymer constituting the fiber base cloth, and R
The FL modifying substance and the like can be arbitrarily selected.

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 in order to compensate for the low weather resistance of the base fabric. However, 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, particularly 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 of the present invention having excellent bending resistance 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, 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 Basis 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.)) 100% by weight of 50% aqueous dispersion and 60 parts by weight of potassium titanate (trademark: Tismo D, Otsuka Chemical Co., Ltd.) are mixed, and a small amount of water-soluble acrylic resin (thickener) is added to this 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 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 as described in JP-A-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. 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 prevention. Class C: When a 3.2 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 D: When melting 3.2 mm thick steel plate for spark generation, through holes harmful for fire prevention are generated. Class E: Flame was generated when a 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.
However, the fire resistance of the sheet of Comparative Example 1 was Class D. 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 exhibited extremely excellent fire insulation properties.

In addition, the heat resistant sheet of the first embodiment is JIS
P 8115 (1976), "Folding endurance test method for MIT type tester for paper and paperboard", it showed almost infinite folding endurance without breaking even after 10,000 times of 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. Organization: Turkish satin weft Warp: DE 150 1/2 3.3S, 51 threads / 2
5.4mm Weft: Same as above, 51 threads / 2
5.4mm Unit weight: 290g / 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 resistance was 1,000 to 2,000.
It was 0 times, which was extremely unsatisfactory.

Example 2 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 spun yarn (30S) of 50% by weight of Conex fiber and 50% by weight of polyethylene terephthalate fiber. The heat-resistant sheet thus obtained had Class C fire resistance and heat resistance, and the folding strength was such that it could withstand bending of 10,000 times or more.

Comparative Example 3 A heat resistant sheet was prepared in the same manner as in Example 1. However,
PTFE (polytetrafluoroethylene, mp 327 ° C.) was used instead of FEP. The heating temperature for forming the heat-resistant coating layer was 350 ° C. as in Example 1. The heat-resistant sheet obtained had a bending test of 10,000
Withstood bending more than 0 times. However, in this heat-resistant sheet, the PTFE was sufficiently melted to cover the base fabric, and the base fabric was not fixed, and easily peeled off from the base fabric by bending. Therefore, this was not practical as a heat resistant sheet and could not be used for the measurement of fire insulation.

Comparative Example 4 A heat resistant sheet was prepared in the same manner as in Comparative Example 3. However,
The heating temperature for forming the heat resistant coating layer was 480 ° C. The obtained heat-resistant sheet had Class B fire resistance and heat insulation, but the result of the bending test was that the sheet was broken after 2,000 to 3,000 times and could not be put to practical use. In addition, the heat-resistant sheet had a base fabric that deteriorated and hardened at a high temperature to become an extremely hard sheet, which could not be used in fire clothes and heat-resistant clothing.

[0057]

EFFECT OF THE INVENTION The heat-resistant sheet of the present invention having excellent bending resistance 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 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 using 00 parts by weight of alkali titanate in combination and forming it at a temperature of 350 ° C. or less, it has both excellent lightweight heat insulation properties and folding strength. Therefore, the heat-resistant sheet having excellent flex resistance of the present invention can be suitably used for applications where it is repeatedly bent or violently vibrates or flicks at high temperatures (for example, fireproof clothing, opening / closing curtains, architectural membrane materials).

[Brief description of drawings]

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

[Explanation of symbols]

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

Claims (4)

[Claims] 1. A base cloth containing 50% by weight or more of 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 bending resistance, which comprises a resin containing and a heat-resistant coating layer containing 1 to 200 parts by weight of alkali titanate per 100 parts by weight of the fluorine-containing resin and fixed at a temperature of 350 ° C. or lower. 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.