JPS602440B2 - Seat manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a sheet with excellent electrical properties, mechanical properties, impregnability, etc., particularly a sheet suitable for electrical insulation.

More specifically, it is a sheet manufacturing method characterized by mixing a wholly aromatic polyester pulp material and short fibers in a specific ratio to form paper, and heating and pressurizing the mixture. Conventionally, natural pulp is the most well-known pulp-like substance used for paper, and paper made from natural pulp is often used as electrically insulating paper.

However, paper made from natural pulp has the major drawback of lacking heat resistance and flame retardancy, and is far from meeting the heat resistance and flame retardance required for reducing the weight and weight of electrical equipment such as motors and transformers. It is something. Furthermore, paper made from natural pulp has the disadvantage of being highly hygroscopic, and when used as electrically insulating paper, it is necessary to take great care in drying to remove moisture and preventing moisture absorption after drying. is very shameful. Recently, pulp-like substances obtained from synthetic polymers have been attracting attention as materials for electrically insulating paper because of their excellent heat resistance and electrical insulation properties.

For example, Japanese Patent Publication No. 35-11851 describes a bulb-shaped material made of a synthetic polymer.

However, when the above-mentioned pulp-like substance is wet-processed to obtain paper, it has poor paper-making properties and it is difficult to obtain a uniform paper with good texture. When this paper is processed and used as electrical insulating paper, it also has the drawbacks of insufficient eel-retaining properties and insufficient electrical insulation properties.

In order to eliminate the drawbacks of paper made from natural pulp and pulp-like substances made from synthetic polymers, the inventor of the present invention, as a result of intensive research, dissolved fully aromatic polyester in a specific solvent,
By introducing this into a precipitant that satisfies specific conditions and precipitating it as fine particles, a pulp-like material with a good shape can be obtained. Even when the paper is made continuously using a fourdrinier paper machine, there are no problems such as paper breakage, and the formation of the paper obtained by drying the sheet thus obtained and heating it under pressure is The present invention was completed based on the discovery that the material is perfect and has excellent electrical insulation properties, impregnation properties, mechanical properties, flame retardance, etc.

That is, the present invention is based on the following method: a) A solution prepared by dissolving a wholly aromatic polyester in an amide solvent is poured into a precipitant consisting of an amide solvent and water, and the concentration of the amide solvent is 20 to 85% by weight. A sheet is prepared by mixing 10 to 9% by weight of a pulp-like substance obtained by introducing the fibers into a sheet and precipitating them as fine particles, and 90 to 1% by weight of short fibers, and heating the sheet under pressure. This is the manufacturing method.

Totally aromatic polyester In the present invention, the wholly aromatic polyester is a polyester obtained by vertically polymerizing one or more aromatic dicarboxylic acids or functional derivatives thereof and one or more dihydroxy aromatic compounds. Alternatively, it is a polyester obtained by condensation polymerization of aromatic oxycarboxylic acid, and examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid.

Further, as the dihydroxy aromatic compound, for example, 202-
Bis(4-hydroxyphenyl)propane [bisphenol A], 111-bis(4-hydroxyphenyl)cyclohexane [bisphenol Z], 1,1-bis(4
-Hydroxyphenyl)ethane "Bis(4-hydroxyphenyl)methane, 1,2-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)cyclohexylmethane, 313-bis(4-hydroxyphenyl) ) Pentane, bis(4-hydroxyphenyl) sulfone, bis(4-hydroxyphenyl) ether, hydroquinone, 404'-dihydroxybiphenyl, etc. Also, examples include "glycol, neobentyl glycol, Aliphatic dihydroxy compounds such as hexamethylene glycol, tetramethylene glycol, trimethylene glycol, and cyclohexane dimethylol may be used as part of the dihydroxy component.Among these aromatic hydroxy compounds, bisphenol A and hydroquinone are particularly preferred. The wholly aromatic polyester may be produced by a well-known method, for example, as described in Japanese Patent Publication No. 37-559 Keitei,
Hakama Publication No. 38-15247, Special Publication No. 38-2629
It can be produced by the method described in Japanese Patent Publication No. y, Japanese Patent Publication No. 1977-195, and the like. Further, other polyesters such as polyester terephthalate or other polymers may be mixed within the range that does not impair the properties of the wholly aromatic polyester.

Amide-based dissolution The amide solvent referred to in the present invention is N.

N-dimethylformamide, N・N-dimethylacetamide "N-methyl-2-pyrrolidone, N-acetyl-pyrrolidone, N-methyl-caprolactam, N-acetyl-caprolactam" A general term for solvents such as hexamethylphosphoramide and tetramethylurea. However, in the present invention, solvents containing N-methyl-2-pyrrolidone as a main component are preferably used.In addition, these amide solvents may be used alone or in combination with other solvents. Polymer Solution When producing the bulb-like substance used in the present invention, a solution of a wholly aromatic polyester dissolved in an amide solvent is introduced into a precipitant consisting of water and an amide solvent,
A method is applied in which the material is precipitated as fine particles to form a pulp-like material.

The concentration of fully aromatic polyester in a solution of fully aromatic polyester dissolved in an amide solvent varies depending on the degree of polymerization and type of fully aromatic polyester, but is generally 5 to 30% by weight.
, preferably 6 to 25% by weight, particularly preferably 7 to 23% by weight
Weight%. When the concentration of the wholly aromatic polyester in the solution is less than 5% by weight, the size of the pulp-like material obtained becomes extremely small, and leakage from the paper-making wire gauze during paper-making is undesirable. On the other hand, if the concentration of fully aromatic polyester in the solution is higher than 3% by weight, the shape of the pulp-like material obtained will be coarse and have few tentacles, and the entanglement of the pulp-like materials and the shortness of the pulp-like materials will be reduced. Entanglement with fibers decreases, paper-making properties deteriorate, and the mechanical properties of the obtained sheet also deteriorate. The temperature during precipitation is 10 to 12°C, preferably 20 to 100°C. Additives Also, a small amount of water may be included in the solution.

Furthermore, it is not necessary to add and mix a minute amount of solid inorganic substance that does not substantially react with or dissolve in the solution, but it can improve impregnating properties, heat resistance, electrical insulation properties, and paper-making properties. This is preferable in terms of improving performance.

In this case, the solid inorganic substances include micas, asbestos,
Glass flakes, quartz powder, talc, kaolin, alumina, etc. can be used. If a solid inorganic material is mixed, the amount is from 5 to 40% by weight of the polymer, preferably from 10 to 20% by weight. When mixing the solid inorganic substance described above into a solution, it is preferable to disperse it as uniformly as possible, and effective devices include, for example, a T.K. be. Precipitant The precipitant used in the production of the pulp material used in the present invention consists of water and an amide solvent,
A precipitant having an amide solvent concentration of 20 to 85% by weight is used.

If the concentration of the amide solvent in the precipitant is greater than 85% by weight, the pulp-like substances produced will coagulate and weld together, resulting in a decrease in the tensile strength and elongation of the sheet obtained by processing this pulp-like substance.
This results in a decrease in dielectric breakdown voltage. In addition, if the concentration of the amide solvent in the precipitant is less than 2% by weight, the shape of the obtained pulp-like material will be rod-like and coarse, and the entanglement of the pulp-like materials and the pulp-like material will be reduced. Entanglement with short fibers decreases, papermaking properties deteriorate, and the mechanical properties and dielectric breakdown voltage of the obtained sheet also deteriorate. The temperature of the precipitant is also one of the important factors for obtaining a pulp material with good paper-making properties and good shape, and is 10 to 70 qo, preferably 20 to 50 qo.

It is preferable that the precipitant be operated at high speed so as to remove the solvent from the introduced solution and at the same time produce a sea bream cutting or beating action. The precipitant/solution flow rate ratio is 5/1 to 3.
The ratio is preferably 0/1, particularly preferably 8/1 to 15/1. (Weight Ratio) Paper Making In the present invention, an excellent sheet is produced by mixing a pulp-like substance and short fibers to make paper.

At this time, the amount of pulp-like material in the sheet is 10 to 90% by weight.
It must be. Particularly preferably, it is 40 to 80% by weight. If the amount of pulp-like material is less than 1% by weight, the mechanical properties and dielectric breakdown voltage of the sheet will deteriorate, which is undesirable.

If the amount of the bulb-like substance is more than 9% by weight, both impregnating properties and mechanical properties will deteriorate, which is not preferable. Paper made from pulp-like substances and short fibers is preferably made by the overflow method using a Fourdrinier or cylinder paper machine, as in the case of conventional paper making from natural pulp. At this time, a surfactant, a polyether, a dispersing agent such as root juice of A. japonica, and a thickening agent may be added as necessary. The monofilament weave of the short fibers used in the present invention is 0.5 to 10 deniers, preferably 1 to 3 deniers.

The fiber length of the short fibers is 1 to 2 lengths, preferably 2 to 15 lengths, particularly preferably 3 to 1 lengths. Various types of short fibers can be used, and examples include the following. 1 Polypropylene fiber 2 Polyethylene fiber 3 Polytetrafluoroethylene fiber 4 Polycarbonate fiber 5 Poly(2,6-diphenylparaphenylene oxide) fiber 6 Polyamide fiber (including aromatic polyamide) 7 IJ ester fiber (including aromatic polyester) 8 Poly IJ acrylonitrile fiber 9 Polyvinyl alcohol fiber 10 Aromatic polyamideimide fiber 11 Polyvinyl chloride fiber 12 Polyvinylidene chloride fiber 13 Glass fiber, birch fiber , inorganic fibers such as asbestos14
Cellulose-based regenerated fibers (viscoutrayon, cupra, etc.) 15 Protein-based regenerated fibers 16 Cellulose-based semi-synthetic fibers (acetate, triacetate, acetate acetate, etc.) Among these, polypropylene fibers with good dielectric properties Short fibers such as , polyethylene fibers, polytetrafluoroethylene fibers, polycarbonate fibers, and poly(2,6-diphenylene-paraphenylene oxide) fibers are used especially to produce insulating paper for high-voltage power transmission cables. It is desirable as a short fiber when carrying out.

In addition, aromatic polyamide fibers, aromatic polyamideimide fibers, aromatic polyester fibers, poly(2,6-diphenylparaphenylene oxide) fibers, etc. are used as insulating paper that requires heat resistance. Useful in manufacturing.

After drying, the sheet obtained as described above can be imparted with excellent performance by heating under pressure using a hot press, a hot roll, or the like.

The temperature at which the pressure is applied varies depending on the type of short fibers and the amount of pulp-like material in the sheet, but a suitable temperature is 70 to 270°C. The pressure is preferably 400k9/mass or less, which varies depending on the temperature, machine, type of short fibers, amount of pulp-like material in the sheet, etc. The method for measuring the main measured values in the present invention will be explained below.

Tensile strength: Performed according to the method of JISP 8118.
9' Boiled.

Elongation: Measured according to the method of JISP 8132 and expressed in %.

Dielectric breakdown voltage: Measured using AC voltage according to the method of JIS C 2111.

Impregnating property: A sample cut into a disk shape with a diameter of IQ skin is JISI
Floating on the surface of the sample insulating oil, measure the time required for the insulating oil to penetrate the entire surface, and divide it by the thickness of the sample to calculate sec/
Expressed with skin.

This measurement was carried out in a vacuum with a ratio of 1 pig Hg. The present invention will be explained in detail with reference to Examples below.

Example 1 Preparation of polymer solution 15 parts by weight of pellets of commercially available wholly aromatic polyester [UP Polymer manufactured by Unitika Co., Ltd.] were ground using a grinder, and 15 parts by weight of N-methyl-2-pyrrolidone 8 with a water content of 0.5% by weight was added.
After pouring the mixture into 5 parts by weight, the polymer was heated to about 180 qo to completely dissolve the polymer.

Then, the temperature of the solution was cooled to 40C0 to prepare a solution for producing pulp-like material. Preparation of precipitant 8 parts by weight of N-methyl-2-pyrrolidone and 2 parts by weight of water were mixed to prepare a precipitant.

Pulp-like material production A pipe light Western type consisting of a combination of a stator with baffles and a turbine blade-shaped rotor, and equipped with a precipitant and solution supply port, and a discharge port for the pulp-like material slurry after precipitation. Add 0.5 [9'm of the above polymer solution to a continuous precipitator.
In, the precipitant was prepared at the same time at a flow rate of 5k9/mjn,
A pulpy material slurry was removed from the outlet.

At this time, the temperature of the precipitant is 3 points, and the temperature of the polymer solution is 4 points.
The temperature was adjusted to 0°C. Also, the rotation speed of the rotor is 800 ratio.
p. m. And so. The resulting pulpy substance slurry was
00 Metsushi. The mixture was placed in a Nutsche-type vacuum furnace filtration machine equipped with a stainless steel wire mesh, and most of the precipitant was separated as a furnace liquid.

Then, without taking out the pulp-like material from the furnace, ion-exchanged water with a volume of 3 of the pulp-like material (solid content) was supplied.
It was then washed under reduced pressure. Contains 1.5 mm (solid content) of the pulp-like material obtained by the above papermaking process and 1.0 mm of polymetaphenylene isophthalamide fiber (trade name: Cornex, manufactured by Teijin) with a monofilament weave of 2 denier and a fiber length of 8 ribs. When paper was made from an aqueous dispersion using a Tappy standard sheet machine, water drained well from the paper-making wire mesh, and the paper-making properties were good. A sheet with good quality and good texture was obtained.

After drying this sheet, it was heat pressed in the first stage under the conditions of 120qC and 250k9', then 180pm and 20k9'.
A second stage of heat pressing was performed under the same conditions as above to obtain paper with a thickness of 170 mm.

The tensile strength of this paper was 5.8 kg/candle, the elongation was 15%, the dielectric breakdown voltage was 17 KV/side, the impregnability was 630 sec/side, and the limiting oxygen index was 39.

Further, when this sheet was left in a dryer at 140° C. for one week, the above-mentioned performance hardly changed and almost no progress of coloring was observed.

Comparative Example 1 In Example 1, the concentration of N-methyl-2-pyrrolidone in the precipitant was adjusted to No. 1 in Table 1 below. Pulp-like materials and sheets were produced therefrom under the same conditions except that the concentrations shown in 1 to 4 were used.

The measurement results for one of these are shown in Table 1. Table 1 N
o. 1 and 2 are examples in which the concentration of N-methyl-2-pyrrolidone in the precipitant is lower than the range of the present invention, and the shape of the pulp-like material obtained in both cases is as shown in FIG.
It became gross.

Furthermore, the surface of the obtained sheet was extremely uneven, and the dielectric breakdown voltage and tensile strength were also low. Also, No. 3 and 4 are cases where the concentration of N-methyl-2-pyrrolidone in the precipitant is too high; In No. 3, the pulp-like material is agglomerated and welded, and the dielectric breakdown voltage of the paper is low.

No. 4 is No. This was a case where the concentration was even higher than 3, and almost no precipitation occurred and a pulp-like material could not be obtained.

Example 2 In Example 1, sheets were obtained by varying the proportions of the wholly aromatic polyester pulp material and polymetaphenylene isophthalamide fiber during paper manufacturing.

The measurement results for these sheets are shown in Table 2.

Table 2 In Table 2, NO. 1 and 2 No. 6 and No. 7 are examples in which the ratio of the wholly aromatic polyester pulp material and the polymetaphenylene isophthalamide fiber in the sheet is outside the scope of the present invention. Although the dielectric breakdown voltage of Nos. 1 and 2 was excellent, the tensile strength and elongation of No. 8 was insufficient. 6. The amount of pulp-like material was too small, and the tensile strength, elongation, and dielectric breakdown voltage were both poor.

Furthermore, “No.

In the case of 7, the wet paper cannot be removed from the paper wire mesh during paper making, and the paper cannot be removed. was not obtained.

On the other hand, No. 3" 4 and 5 were obtained by the method of the present invention, and both tensile strength and elongation and dielectric breakdown voltage were at satisfactory levels.

Example 3 Diphenyl terephthalate 21QQ Kani Gunbu "Diphenyl isophthalate 171, 9 parts by weight, Bisphe/-l A2
87. A reaction vessel was charged with 0.14 a part by weight of stannous acetate, and reacted at 280 qo normal pressure for 60 minutes in a nitrogen atmosphere.Then, the pressure was gradually reduced, and after 3 minutes, the absolute pressure reached 0.
．． After reaching 5 willow Hg or less, the solidified polymer was taken out and ground into a powder of about 20 mesh.

15 at an absolute pressure of 0.5 Hg or less and 300 qo
Solid phase polymerization was carried out for 0 minutes to obtain 41 parts by weight of a wholly aromatic polyester. Phenol/tetrachloroethane (60/4
The reduced viscosity measured at 35q0 by dissolving 1.2 parts of the polymer in 100 parts of a mixed solvent (0 weight ratio) was 1.03.
A pulp-like material and a sheet were obtained from it in the same manner as in Example 1, except that the thus obtained wholly aromatic polyester was used as the wholly aromatic polyester. The performance of this sheet is
It was almost the same as the sheet obtained in Example 1 and was good. Example 4 191 parts by weight of diphenyl terephthalate, 16.5 parts by weight of bisphenol AI, 16.5 parts by weight of hydroquinone, and 0.071 parts by weight of stannous acetate were operated in the same manner as in Example 3 to obtain a total of 1.0 parts by weight of reduced viscosity. 19 parts by weight of aromatic polyester were obtained.

In addition to using the thus obtained wholly aromatic polyester as the wholly aromatic polyester, setting the humidity of the polymer solution used for precipitation to 10 pi○, and setting the polymer concentration in the solution to 1% by weight. A pulp-like material and a sheet were obtained from it in the same manner as in Example 1. The performance of the sheet was as follows, and all were good.

Tensile strength 6.0k9/fence, elongation 13.5%, insulation breakdown pressure 1 ship V/rib, impregnation 70$ec/skin.

Example 5 Pulp-like material 1 of wholly aromatic polyester obtained in Example 3
．． 6 obtained by thoroughly washing and cutting a 100 denier 48 filament bright fiber of a 2 day (solid content) aqueous dispersion and polyethylene terephthalate with a 70% neutral detergent aqueous solution, methanol and water. Short willow fibers were mixed with 0.8 ml of a water solution and made into paper using the same equipment used in Example 1.

The papermaking property was excellent, with good water drainage from the wire mesh, and a good overflow of paper was obtained. After drying this wet paper, 11000, 2
The first heat press was carried out under the condition of 00 kg' ground, and then the first stage was heated.
A second heat press was performed under the conditions of 80 x 9' sheets to obtain a sheet with a thickness of 0.13 ribs.

The properties of this sheet were as follows, and all were good. Tensile strength 5.6kg'Tensile strength 18%
, impregnation, total ec', dielectric breakdown voltage: 15. Example 6 The pulp-like material obtained in Example 3 was mixed with 1.5 liters of water (solid content) and poly(216-diphcoC-paraphenylene oxide) fibers with a fiber length of 6. [Netherlands AK20
After mixing 0.5 hours of water dilution solution (manufactured by TENAX), add a small amount of non-ionic surfactant KOLBT-7 (product name of Nippon Chemicals Co., Ltd.) and root juice of A. The mixture was stirred until the fibers and pulp-like material were completely dispersed and mixed.

Next, paper was made using the same equipment as used in Example 1 to obtain green paper with good texture. After drying this overflow paper at 105℃,
The first stage of heat pressing was carried out under the conditions of 50qo and 200kg' fins, and then the second stage of heat pressing was carried out under the conditions of 20p0 and 10k9/c fins to obtain a sheet with a thickness of 0.13.

The performance of this sheet was as follows, and all were good. Tensile strength: 4.3k9 Tensile elongation: 14.6%
, Impregnation 9"6"ec' ribs "Dielectric breakdown voltage 2 chicks V' side.

Claims (1)

[Claims] 1 (a) A solution of fully aromatic polyester dissolved in an amide solvent is introduced into a precipitate consisting of an amide solvent and water with stirring and the concentration of the amide solvent is 20 to 85% by weight to form fine particles. 10 to 90% by weight of a pulp-like substance obtained by precipitation and (b) 90 to 10% by weight of short fibers.
A method for producing a sheet, which comprises mixing paper-making, pressurizing and heating.