JPS5911720B2 - sheet - Google Patents

Description

[Detailed description of the invention] The present invention relates to sheets.

More specifically, an optical anisotropy composed of a polymer mainly consisting of at least one carbocyclic aromatic homo- or copolyamide in which bond chains extend coaxially or parallelly from each aromatic ring. This invention relates to a sheet formed by mixing pulp particles obtained by precipitating a solution with short fibers and heating the mixture under pressure.

Conventionally, natural pulp is the most well-known pulp particle used in paper.

However, the above-mentioned paper pulp particles have poor heat resistance and flame retardancy.

In recent years, pulp particles made of synthetic polymers have been known to eliminate these drawbacks.

For example, Japanese Patent Publication No. 35-11851 describes a pulp-like object made of a synthetic polymer;
Publication No. 3912 describes a method for producing a sheet made of the above-mentioned freshly formed pulp 7-like object and fibers.
However, such pulp particles are obtained by precipitation from a homogeneous solution of synthetic polymer powder;
Hard polymers and soft polymers are mentioned as the polymers constituting the pulp particles, but the solution of either of them does not exhibit optical anisotropy. Heat resistance of paper, 5 flame retardance is poor.

7) In order to eliminate such drawbacks, the present inventors have made an optically anisotropic solution of a carbocyclic aromatic polymer in which bond chains extend coaxially or parallelly from each aromatic ring as a result of intensive research. By manufacturing the resulting pulp particles and fibers, a synthetic paper with excellent heat resistance and flame retardance can be obtained, thus completing the present invention.

That is, the present invention comprises dissolving in a solvent a polymer mainly consisting of a carbocyclic aromatic homo- or copolyamide without side chains, in which bonding chains extend coaxially or parallelly from each aromatic ring. The obtained optically anisotropic solution is stirred and then added to a precipitating agent, and pulp particles and short fibers obtained by precipitation are mixed, followed by pressurization and heating.

n The polymer used in the present invention consists primarily of at least one carbocyclic aromatic homo- or copolyamide in which the linking chains extend coaxially or parallelly from each aromatic ring.

Here, 35 is an example of an aromatic ring in which the bonding chain is coaxial, such as 01,4-phenylene (tan4,4'-diphenylene 11-), and even if these aromatic rings have substituents, However, the substituents must be such that they do not undergo undesirable reactions during polymerization and processing steps.

Examples of such substituents include halogen groups (e.g. C
t, Br, F). The above polymer chain consists of an amide bond (-CONH-) and an aromatic ring,
Items that do not meet the above conditions, such as aromatic polyamide bonds that do not extend coaxially or parallel to the aromatic ring (e.g. meta-orientation), urea bonds, ester bonds, hydrazide bonds, etc. Polymers containing about 10 mol% of bonds other than amide bonds can also be used. Examples of aromatic polyamides suitable for the present invention include the following.

Poly(p-benzamide) Poly(p-phenylene terephthalamide) Poly(2-chloro-p-phenylene terephthalamide) Poly(p-phenylene-2,6-naphthalene dicarboxylic acid amide) Poly(2,6-dichloro - p-phenylene-2,6-naphthalene dicarboxylic acid amide) poly(P, pl-phenylene benzamide) poly(1,5-naphthylene terephthalamide) regular aromatic copolyamide (e.g. P, p5-
Diaminobenzanilide-terephthalamide copolymer) Random copolyamide (e.g. p-benzamide/p-
and phenylene terephthalamide 50/50.

) These polymers are used as homopolymers alone, copolymers alone, mixtures of homopolymers, mixtures of homopolymers and copolymers, and mixtures of copolymers.

The above polymer can be synthesized by a known method such as a low temperature solution polycondensation method of an aromatic dicarboxylic acid halide and an aromatic diamine, or a method from a hydrohalide salt of an aromatic aminocarboxylic acid halide.

The optically anisotropic solution used in the present invention is obtained by mixing a polymer, a solvent, and a salt in a certain concentration range, but such a solution exhibits birefringence, and when polarized light is passed through the solution, it becomes depolarized. A phenomenon is observed.

The above-mentioned optically anisotropic solution is described in Japanese Patent Publications No. 47-2489, No. 47-39458, No. 47-43419, etc., and is well known.

The optically anisotropic solution used in the present invention consists of the above-mentioned specific solvent, and the combination of polymer and solvent to provide the optically anisotropic solution must be appropriately selected.

The solvent used in the Vc of the present invention is appropriately selected depending on the type of polymer. Such solvents include N,N-dimethylacetamide, N,N-dimethylpropionamide,
N,N-dimethylbutyramide, N,N dimethylisobutyramide, N,N-dimethylmethoxyacetamide,
N,N-diethylacetamide, N-methyl-2-pyrrolidone, N-methyl-2-piveridone, N-methylcaprolactam, N-ethyl-2-pyrrolidone, N-acetylpyrrolidine, N-acetylbiveridine, N, N5-dimethylethyleneurea, N,N゛-dimethylpropyleneurea, hexamethylphosphoramide, N,N,N',N'
- Concentrated sulfuric acid, an amide organic solvent such as tetramethylurea,
Inorganic solvents include fuming sulfuric acid, hydrogen fluoride, chlorosulfuric acid, fluorosulfuric acid, and methyl sulfuric acid.

The organic solvent is one type or a mixture of two or more types, and is a solvent containing one type or two or more types selected from hydrochloric acid, lithium chloride, potassium chloride, and calcium chloride. The pulp particles in the present invention may contain inorganic filler particles having good heat resistance inside.

Such inorganic filler particles include mica, asbestos,
Examples include glass fiber, glass flakes, quartz powder, talc, alumina, calcium sulfate, calcium carbonate, kaolin clay, diatomaceous earth, feldspar powder, magnesium carbonate, and magnesium oxide. The present invention Vc. In preparing the pulp particles, a solution of a polymer consisting primarily of at least one carbocyclic aromatic homo- or copolyamide in which the bonding chains extend coaxially or parallelly from each aromatic ring is dissolved. The filler may be added at the time of polymerization, or the filler may be added to the solvent together with the raw materials for post-polymerization, or a solution to which the filler is added during polymerization may be used. . In the present invention, the short fibers used in paper-making from the bulp particles are preferably heat-resistant fibers, and usually have a fineness of 0.5 to 10 deniers and a fiber length of 1 to 20 deniers. . As such heat-resistant fibers, those having better heat resistance than general-purpose thermoplastic synthetic fibers are used, and for example, the following fibers are used. 1. The short fiber aromatic polyamide made of aromatic polyamide is (1) a condensation polyamide of a highly active derivative of a dicarboxylic acid having an aromatic ring, preferably an acid, such as lard, and a diamine having an aromatic ring.

For example, dicarboxylic acids such as terephthalic acid and isophthalic acid, diamines such as metaphenylenediamine, 4,45-
A type of dicarboxylic acid using diaminodiphenyl ether, 4,4'-diaminodienylmethane, xylylene diamine, N-methyl-paraphenylene diamine, etc.
It may be a homopolymer consisting of a kind of diamine,
It may be a copolymer consisting of two or more compounds of either or both of the dicarboxylic acid component and the diamine component. Typical examples include polymethphenylene isophthalamide, polymethaxylene terephthalamide, a copolymer of metaphenylene diamine, isophthalic acid and terephthalic acid, and polyN-methylparaphenylene terephthalamide.

(2) A polyamide in which an aminocarboxylic acid having an aromatic ring is preferably activated and condensed.

For example, a homopolymer made of only one type of aminocarboxylic acid such as para- or meta-aminobenzoic acid, para-aminomethyl benzoic acid, etc. is used. It may be a copolymer of two or more aminocarboxylic acids.A typical example is a condensate of para-aminobenzoic acid. (3) Preceding α1》, (2) Typical examples of copolymerized polyamides include polyamides in which metaphenylenediamine, isophthalic acid chloride, and para-aminobenzoic acid chloride hydrochloride products are combined. Short fibers consisting of a carbocyclic aromatic homo- or copolyamide extending in parallel directions.

Among the above-mentioned carbocyclic aromatic homo- or copolyamides, carbocyclic aromatic homo- or copolyamides in which bonding chains extend in the coaxial direction or parallel direction are the same as those described above.

The short fiber nitrogen-containing cyclic compound consisting of a nitrogen-containing polyheterocyclic compound is (1) aromatic polyamide, where X is an alkylene, alkyldene, cycloalkylene or cycloalkylidene group having 1 to 6 carbon atoms -0-,- S-1 SO2-,! 1I-N
=N-, -N: Consists of a group selected from N-, -Sll-, -Y-0.

Here, R is an organic group having 1 to 10 carbon atoms, Y,
Y' may be the same or different, and each = is a hydrocarbon group having 1 to 6 carbon atoms, a halogen atom, an ArylOxy group having 1 to 3 carbon atoms, 2
Carbalkoxy group having ~10 carbon atoms, 1-5
m and n, which are at least one selected from alkoxycarbonyl groups having carbon atoms, may be the same or different, and are 0 to 3.

The polyamideimide of the above formula is composed of at least 70 mol%, preferably 85 mol% or more, and in particular, X is -CH2-
, -0-, -SO2-, Y, and Yl are preferably a methyl group, a halogen atom, or a methoxy group, and M and n are preferably O or 1.

The polyamideimide contains up to 30 mol%, especially up to 15%7.
．． ．． ．． b Contains repeating units.

where R is an alkali having 2 to 15 carbon atoms5).)
It is.

Up to 30 mol %, in particular up to 15 mol %, of the repeating units are polyamidebenzimidazole, aromatic polyimide, aromatic polyamide polyazole such as polyoxazole, polyoxadiazole, polythiazole, polythiadiazole polypenazole such as polybenzimidazole, poly It may also contain benzothiazole, polybenzoxazole polyhydantoin, polyparabanic acid, polyquinazolinedione, polyquinazolone, polyquinoxaline, and polyoxazinone.

<<2) Polyazole, such as polyoxazole, polyoxadiazole, polythiazole, polythiadiazole. (3) Polybenzazole, such as polybenzimidazole, polybenzothiazole, polybenzoxazole (4) Polyhydantoin, polyparabanic acid, polyquinazolinedione, polyquinazolone (5) Polyquinoxaline, polyoxazinone 4. Precursor of nitrogen-containing polyheterocyclic compound As a precursor of a short fiber nitrogen-containing polyheterocyclic compound consisting of a short fiber nitrogen-containing polyheterocyclic compound, the formula (1) is ?-HN-YOl'.

-ゞ087R; Same as above] Polymer having units represented by g-0H (precursor of polyamideimide) (2) Aromatic polyhydrazide, aromatic polyurea (3) Aromatic polyamide hydrazide Formula -×{[ ] A polyamide hydrazide having a unit represented by 卜×-NHNH-.

These may have an inert substituent such as a methyl group, an alkoxyl group, or a halogen atom.

Precursors obtained by copolymerizing these precursors with aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid, benzoJGnontetracarboxylic anhydride, pyromellitic anhydride, etc. can also be used. 5. Short fiber aromatic polyethers made of aromatic polyethers include polyphenylene oxide and polyarylene oxide.After drying, the sheet obtained as described above is heated under pressure using a means such as a hot press or a hot roll. This makes it possible to produce superior synthetic paper.

The appropriate temperature for pressurizing is 140°C to 400°C.

Pressure is 200Kf/Cr! i or less is desirable.

The sheet of the present invention as described above has particularly excellent flame retardancy and heat resistance, as well as mechanical properties such as tensile strength and tensile strength, compared to conventional polymetaphenylene isoptamide paper. It also has good properties such as electrical insulation and impregnability. Therefore, the sheet can sufficiently perform its functions even under severe conditions where conventional electrically insulating paper cannot be used. Hereinafter, the present invention Vc. Describe the measurement method for the main characteristic values.

Logarithmic viscosity: Measured at 30° C. in concentrated sulfuric acid or N-methyl-2-pyrrolidone at a concentration of 0.5 r/100 ml.

Tensile strength: Measured by the method of JISP8ll3, Kf
/71d.

Tensile elongation: Measured by the method of JISP8l32 and expressed in %.

Oxygen index: In accordance with ASTM D2863-70, the oxygen percentage was determined when the flame continued to burn for about 1.5 hours with upward ignition while supporting downward.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Hexamethylphosphoramide 50d<5N-methyl-2
- Dissolve 5.66 r of paraphenylene diamine in a mixed solvent of 100 d of pyrrolidone, add 3.87 t of lithium carbonate, cool in an ice bath, and then dissolve the powder of terephthalyl chloride 1.
0.63r was added.

An optically anisotropic solution was obtained after about 30 minutes. Poly(p-phenylene terephthalamide) thus obtained
Logarithmic viscosity ηInh. was 2.75. This optically anisotropic solution contains about 7.5% by weight of polymer. This optically anisotropic solution was introduced into 1 ton of water in a homomixer that was being stirred at high speed, and after the introduction, the mixture was further stirred at high speed for about 5 minutes to obtain a precipitate. The precipitate thus obtained was separated and washed to obtain pulp particles.

A fiber obtained by wet-spinning such pulp particles and an N-methyl-2-pyrrolidone solution of polymetaphenylene isophthalamide (logarithmic viscosity 1.9 in concentrated sulfuric acid) and heat-treating the drawing was
Short fibers cut into lengths of wm were mixed in various proportions and paper was made to obtain sheets.

After drying this sheet, it was hot pressed at 290° C. and 200 Kf/Cd to obtain paper. The results are shown in Table 1.

Samples 2 to 4 in the table were made according to the present invention and had excellent tensile strength and elongation.

Rating No. 1 was a case in which there were too few pulp particles, and Rating No. 5 was a case in which there were too many pulse particles, and the tensile strength and elongation were poor. Example 2 An optically anisotropic solution of poly(p-phenylene terephthalamide) obtained in the same manner as in Example 1 was introduced into about 1 ton of water, and the resulting mixed aqueous solution was placed in a homomixer. and stirred at high speed for about 20 minutes.

After washing the obtained pulp particles with water, a sheet made of 70% by weight and 30% by weight of polymetaphenylene isophthalamide fibers was dried, and the physical properties of the hot-pressed paper had a tensile strength of 0.6K9/Mll. The tensile elongation was 3%.

Example 3 In Example 1 and 3, trimellitic anhydride, 4,4'
- When using short fibers obtained by wet-spinning polyamideimide obtained from diphenylmethane diisocyanate and 4,41-diaminodiphenylmethane, drawing and heat-treating the fibers and cutting them into a length of 5wr1f1, the physical properties of the paper obtained are as follows: The tensile strength was 0.5K9/7ZI1 and the tensile elongation was 4%.

Comparative Example 1 When an optically anisotropic solution obtained in the same manner as in Example 1 was diluted by adding 300 Tne of a mixed solvent of hexamethylphosphoramide and N-methyl-2-pyrrolidone (volume ratio 1:2). Although an optically isotropic solution was obtained, the solution viscosity was too high, the fluidity was poor, and it was difficult to introduce it into the precipitant.

Example 1: Adding 150 me of the above mixed solvent to this solution and diluting the resulting low viscosity optically isotropic solution (polymer concentration of about 2% by weight) into water being stirred at high speed. Although precipitation was carried out under the same conditions as above, good pulp particles could not be obtained.

A sheet made from 70% by weight of such pulp particles and 30% by weight of polymetaphenylene isophthalamide fibers was dry-sheeted and hot-pressed at 250°C and 200Kf/Crli, and the physical properties of the paper were as follows: Tensile strength: 0.2K9/11d Tensile elongation It was 1%.

Example 4 Flat 3VC of Example 1. Additionally, instead of the polymetaphenylene isophthalamide short fibers, poly(p-phenylene terephthalamide) short fibers (fineness 1.8 de, fiber length 5) were used.
After drying a sheet made from paper (rrrIn), it was heated at 400°C for 2
The physical properties of paper heat pressed at 00Kf/Cd are tensile strength
The tensile elongation was 0.5K9/M7l and 3%.

Example 5 After introducing the entire optically anisotropic solution of poly(p-phenylene terephthalamide) obtained in the same manner as in Example 1 into about 1 ton of water, the resulting mixed solution was placed in a homomixer. The mixture was transferred and stirred at high speed for about 20 minutes.

The obtained pulp particles have a similar morphology to the particles obtained by the method of Example 1. Such pulp particles 70
Weight% and Polymetaphenylene Isophthalamide Short Fiber (
The physical properties of paper consisting of 30% by weight (with a fineness of 2de and a fiber length of 5wm) are a tensile strength of 0.6Kf/7! TJ tensile elongation was 4%.

Example 6 Poly(p-phenylene terephthalamide) (logarithmic viscosity η
Inh. 5.5O) 10f and concentrated sulfuric acid 100ff1C. The optically anisotropic solution obtained by dissolving the optically anisotropic solution was mixed with about 1 t1 of ice water in a stirred homomixer. After washing with water, the mixture was vigorously stirred with water in a homomixer and washed again with water to obtain pulp particles.

The physical properties of paper made of 70% by weight of such pulp particles and 30% by weight of polymetaphenylene isophthalamide short fibers (fineness: 2 de1 fiber length: 5 mm) are as follows: Tensile strength: 0.6j7J (p-phenylene 2,6-naphthalene dicarpoxamide) (logarithmic viscosity ηi = 2.52)
The optically anisotropic solution obtained by dissolving the solution in 00f was heated with ice water for about 1 trC in a homomixer, and then stirred at high speed.

After washing the obtained pulp particles, the physical properties of the paper consisting of 70% by weight of the pulp particles and 30% by weight of polymetaphenylene isophthalamide fibers were as follows: tensile strength: 0.5K9/shoulder J; tensile elongation: 49b.

Example 8 Poly(p-benzamide) 10? and 6.5% by weight of lithium chloride in a tetramethylurea lithium monochloride solution 9
The optically anisotropic solution obtained by slowly heating and cooling the 0f mixture was slowly introduced into approximately 2 tons of gently stirring water.

Thereafter, the precipitate of the aqueous solution mixture and 2001 nt of water were vigorously stirred in a homomixer and then washed with water to obtain pulp particles dispersed in water.

The physical properties of the paper consisting of 70% by weight of the pulp particles and polymetaphenylene-sophthalamide short fibers (fineness: 2 de 1, fiber length: 5 l) were as follows: tensile strength: 0.6 Kf/MJ; tensile elongation: 4%.

Example 9 Regarding paper No. 3 of Example 1, 0N-1 manufactured by Toyo Rika Kogyo Co., Ltd.
The oxygen index was determined to be 38.0 using a type flammability tester according to the method of ASTM D2863-70, and the flame retardance was extremely excellent.

As a comparison, paper made of polymetaphenylene isophthalamide had an oxygen index of 28.

Example 10 Table 2 shows the results of the paper No. 3 of Example 1 left at 270° C. for two weeks.

In flat 3, there was almost no decrease in strength and elongation due to heat treatment,
It had excellent heat resistance.

Claims (1)

[Claims] 1. Optical anisotropy obtained by dissolving in a solvent a polymer consisting mainly of carbocyclic aromatic homo- or copolyamides without side chains, in which bonding chains extend coaxially or parallelly from each aromatic ring. A sheet made by mixing pulp particles obtained as a precipitate by adding them to a precipitant and heat-resistant short fibers while stirring an isotropic solution, making paper, and pressurizing and heating the mixture.