JPS5876598A - Production of polyester paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing polynisder paper having excellent strength, heat resistance, and electrical insulation properties.

Conventionally, polyester paper and film have excellent mechanical and electrical properties, so they have been widely used as insulating materials and various base materials for electrical equipment.

However, recently, there has been a growing concern for improving the heat resistance of electrical materials, and conventional polyester fillers and polyester paper are said to be insufficient due to their inferior heat resistance5.

For this reason, papers and films made of various heat-resistant polymers such as aromatic boria Z-doped and polyimide have been developed and are becoming increasingly popular. However, these ML polymers are expensive and, in some fields, have low ML properties, so there has been a strong demand for low-cost heat-resistant materials.

In order to improve the strength and heat resistance of polyester paper, the inventors of the present invention conducted intensive studies on the manufacturing and processing conditions of polyester paper, and found that it has high strength and excellent heat resistance that could not be obtained with conventional filled paper. The inventors discovered that positive ester paper could be obtained and arrived at the present invention.

That is, 1. The present invention is based on a paper made and dried sheet mainly composed of polyester pulp of 50 to 5 QQeC and polyester short fibers of 6 densities or less. This is a method for producing polyester paper, which is characterized in that after hot-pressing at a temperature, heat treatment is performed at a temperature higher than the temperature of the hot-pressing and lower than the melting point.

In the present invention, positive ester paper is produced using polyester pulp and polyester staple fibers as main components. Polyester fibers and polyester short fibers include terephthalic acid, isophthalic acid, oxybenzoic acid, 7) (acid components such as tinnic acid and ethylene glycol, 7' a k'
Recall Recall.

A polyester obtained by condensation polymerization or copolymerization with a glycol component such as neopentyl glycol, diethylene glycol, or tetramethylene gelyl is pulped and edged.

The r ice charcoal of the polyester pulp used in the present invention is 5G
-5 o 6 cc, preferably 100 to 400 cc. If P Suisan is too large, sufficient electrical insulation effect cannot be obtained, and if it is too small, paper making becomes difficult. If P Suisan is within the above range, any manufacturing method can be used. Although polyester pulp can be used, pulp obtained by dividing, melting, or pounding oriented crystallized m# is preferably used because it has excellent heat resistance.

In other words, 1) a method for producing synthetic pulp is generally a) method C in which a synthetic polymer S* is allowed to flow down into a poor solvent for the polymer while applying a shearing force, and precipitated in the form of a single fibre.
Fibrid method: Tokkosho is -1, Fuiz, 9. Precipitation, one method, one layer, shearing method: Japanese Patent Publication No. 111118/1983).

c) A method of mixing two or more incompatible synthetic polymers and melt-extruding or spinning) c) A method of forming WNa-like fibrils by mechanical means (split method: Japanese Patent Publication No. 35-11
681 etc.).

2) Method C of mixing two or more incompatible synthetic polymers, melt-extruding or spinning), immersing the cutting edge in a solvent, and dissolving one of the polymers in the solvent to form #I #1 fibrillation. (U.S. Patent No. KhsszsoIs, etc.).

e) The synthetic polymer is explosively ejected from the high pressure side to the low pressure side at a temperature higher than the boiling point of the solvent, and then beaten.
Method of ficrylization C Flash spinning method: % Komei 3
6-1 @ No. 460, etc.).

f) Blend a polyester-based polymer with an alkaline solution-soluble component that is incompatible with the polyester, reduce the weight by changing the burqa, and then beat it. ! How to fibrillate C full force u
A method in which * is obtained from oriented crystallization using beating method = 4I is preferred.

Among them, the alkali weight loss beating method can be applied to polyesters, and since oriented crystallized m- is obtained with a volume of 14, the heat resistance is excellent, and it is particularly preferably used.

Zero shot 91! The short polyester fibers used in
If it becomes too much, the electrical insulation properties will decrease and the paper-making properties will also deteriorate. In addition, the shrimp may be an undrawn yarn that has gone through the usual spinning process (or it may be a drawn yarn that has gone through the spinning and heron drawing processes. It may be an intermediately oriented yarn, or it may be a yarn obtained by further processing such as drawing or heat treatment on the intermediately oriented yarn.Furthermore, unsagi drawn yarn, drawn yarn, intermediately oriented yarn can be used as a short-toothed yarn. Two or more types of Mi-- such as threads may be mixed.

In particular, the unstretched system is used as a part of the short-anchor strength.

When using an unstretched system containing 20% by weight or more of the main components including bulbs, it is preferable to pass through an over-current paper making and drying factory without using piping (both are preferable because a sufficiently high mechanical strength can be obtained). , the edge line length of polyester staple fibers is 2~ls+
W rootiness is appropriate.

The polyester paper of the present invention does not contain polyester fibers and polyester short #a edges as its main components.

It is necessary that the proportion of each to the total paper does not fall below 20 weight. If the pulp component is too low, the electrical insulation properties, especially the dielectric breakdown voltage, will be low, and if the short fiber component is too low, the strength will be low. In some cases, the polyester paper of the present invention! s% or less, may contain pulp, particulate matter, and other solid substances, i.e., inorganic fibers such as glass fiber, inorganic particles such as sizing agents, binders, etc., within a range that does not impair heat resistance. may contain organic matter.

In the present invention, the polyester paper is subjected to heat and pressure processing after papermaking,
Next, it is heat treated and heat pressure processed.

Calendar dyeing usually used to process a single sheet of paper The heat processing temperature is 120°C or higher.

It is necessary that the heat treatment temperature is higher than the temperature of the hot-pressure processing and lower than the melting point. Here, the melting point refers to the lowest melting point of polyester pulp and polyester short fibers. In addition, when 8 or more types of #lIm, including drawn threads and undrawn thread rings, are used as polyester short fibers, it means the lowest melting point among polyester pulp and various types of polyester short lII embroidery. If the S-pressing temperature is less than 120°C, the paper strength, ruff resistance, and electrical insulation properties will be poor, and if it exceeds the melting point, fusion will occur, which is inappropriate. Furthermore, if the heat treatment temperature after hot-pressing processing is lower than the hot-pressing processing temperature, the strength, heat resistance, and electrical insulation properties of the paper will decrease, and if it exceeds the melting point, fusion will occur, so this must be avoided. The treatment is usually carried out in a constant length or tensioned (stretched) state, but free shrink heat treatment may also be carried out.

The polyester paper obtained by the method of the present invention has excellent heat resistance, dimensional stability in the <Vc'l&temperature range, and excellent heat deterioration resistance in the medium temperature range. As mentioned above, such excellent heat resistance can be obtained by paper-making polyester pulp and polyester maim, subjecting them to hot pressure processing, and then heat-treating them. Polyester paper that is strong, has excellent heat resistance, and electrical insulation properties can be obtained.

The polyester paper of the present invention has the above-mentioned excellent strength, heat resistance, and electrical insulation properties, so it can be used as an insulating material and various base materials (K electrical insulation paper).

Can be used for adhesive paper, flexible printed circuit boards, etc.

The method of the present invention will be explained in detail with reference to Examples below. In the Examples, the method of measuring the characteristic values of the paper used is as follows.

The sample paper was exposed during opening for deterioration with heat resistance temperatures set at 210°C, 1110°C, and 170°C, and the exposure time was determined until its elongation decreased to sO% of the elongation before exposure to heat. , plotted on a graph with the logarithm of time on the vertical axis and the reciprocal of absolute temperature on the horizontal axis.

The temperature extrapolated to 2QOOO time from the three-point least squares method was defined as the heat resistance temperature of the sample paper. These steps are I'E
a I followed CPubllation 8s. This heat resistance temperature indicates that the heat resistance is good.

Oil immersion shrinkage rate: A sample paper was immersed in oil heated to 230°C for 20 seconds, and the shrinkage rate was determined from the length of the sample paper after immersion in the casing.

Dielectric breakdown voltage: Constant based on JI8C-116.

The larger this value is, the better the electrical insulation is.

P Fisheries RCC): JI8P Hatame'K Accordingly, the pulp was prepared using a Canadian standard type device (Canada Standard FV-Nest Tester manufactured by Kumagai Masuki) K to a dope of concentration (L1% by weight) and the P bark was fixed.

Examples Polyethylene terephthalate (3) obtained by conventional methods
1C of 0-ta cI lophenol solution with constant intrinsic viscosity aSS) was metered with a gear pump at 21 °C gsst'
c<Feeding to heated kneading screw. On the other hand, a mixture of sodium alkyl sulfonate having a carbon number of 8 to 20 and an average bulk number of 14 was weighed with a gear pump at 150°C.
The mixture was supplied to the mixed screw heated to 85°C. The mixing ratio of sodium alkylsulfonate to polyethylene terephthalate was 4% by weight. The blended polymer mixed using a mixed screw was extrusion molded to obtain a tube-shaped molded product.

The obtained chips were discharged using a nozzle having a horseshoe-shaped opening in which a part of the dry VK annular slit was opened, and melt-spun according to a conventional method to obtain hollow fibers. These raw yarns are combined and drawn.

Heat set, 170,000 d・tow (AA 41I-denier 1
．． 5) was obtained. After cutting this tow into 3 pieces with a guillotine cutter, add a caustic soda aqueous solution (sol/l) K maintained at is°C ± 1"CK at oO, #l & place with stirring, rinse with water, After drying, it was dispersed in water, and the slurry having a concentration of 1% was beaten using a Kumagai Seiki Disc Refineer to obtain a pulp with embroidered fibrils of P 1711ce.

On the other hand, 1 unstretched polyethylene pre-7 spun in a conventional manner.
Tallate short fin embroidery (Llde am length 5 mm, birefringence a0
10.1 and polyethylene terephthalate short thin wire (AIDO, 41111) drawn 22 times.
wm) with the above-mentioned pulp at various ratios to obtain sheets with a basis weight of 4 o i/d. The paper was made using a square sheet machine and dried in a drum dryer at a surface temperature of 310°C. The obtained sheet was passed through a calendering machine consisting of metal rolls and heated on both sides. Linear pressure of one calendar is 200
It was 9/trust. After calendering, the obtained sheet was subjected to constant length heat treatment for 3 minutes.

The following table shows the blending conditions of polyester pulp and polyester tankama embroidery, processing conditions C calendar rule surface temperature, heat treatment temperature, and characteristic values of the obtained paper.

4ri, which has a small pulp mixture ratio, has a low insulation am voltage (and #!
Both 1 ic pressures were high.

It was found that the yarns containing 15% and 25% (undrawn yarn) may cause problems such as sheet breakage during the manufacturing process;
+, and no problems with the type of work were expected. , 47, the calendar temperature is low.

In rot 8, the heat treatment temperature was lower than the calendering temperature, so the resulting paper was inferior in strength, heat resistance temperature, oil immersion shrinkage rate, and dielectric breakdown voltage. , 49 to 12 were all under appropriate processing conditions and exhibited excellent characteristic values.

Claims (1)

[Claims] A sheet made and dried from a polyester pulp whose L P ice charcoal is sO to 1 Occ and a polyester short cloth having a denier of 6 deniers or less and dried at 12 o, °C.
As described above, a method for producing polyester paper is characterized in that after hot-pressing processing is performed at a temperature lower than the melting point, heat treatment is performed at a temperature higher than the temperature of the hot-pressing processing and lower than the melting point. 2. Claims mw* in which the content of polyester pulp and polyester fiber is each more than go% by weight
The method described in section. 1. The method according to claim @mtsx, which contains 20% by weight or more of polyester undrawn yarn as a short polyester fiber anchor. Also, heat treatment after hot pressure processing is fixed length or 1I41III&
The method according to Claims S, Section 1, Jl1m, or Section 3, which is a field.