JPS5876597A - Production of polyester paper with excellent heat resistance - 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 relates to a method for producing polyester paper having excellent strength and heat resistance.

Conventionally, polyester papers and films have excellent mechanical and electrical properties and have therefore been used as insulating materials and various base materials for electrical applications. However, recently, there has been a growing demand for improved heat resistance in electrical materials, and it has come to be said that conventional polyester films and polyester papers are insufficient in terms of heat resistance.
Papers and films made from various heat-resistant polymers, such as polyamide, have been developed and are becoming increasingly popular. However, these heat-resistant polymers are expensive and have limited performance in certain fields, so there has been a desire to develop low-cost heat-resistant materials.

In order to improve the strength and heat resistance of polyester, the present inventors conducted intensive studies on the papermaking and processing conditions of polyester paper, and found that polyester has high strength and excellent heat resistance that could not be obtained with conventional films or paper. I discovered that paper could be obtained and arrived at Honsha #4.

That is, the present invention mainly uses stretched polyester HI embroidery of αl to 1.5 deniers and unstretched polyester II embroidery of 2 to 1 denier, and tests the glass transition point of the unstretched polyester fibers on paper-made and dried sheets. 5 from temperature
Higher than 0℃.

This is a method for producing polyester paper with excellent heat resistance, which is characterized in that after hot-pressure processing at a temperature lower than the melting point, heat treatment is performed at a temperature higher than the temperature of the heat processing and lower than the melting point.

In the present invention, polynisdel paper is produced using drawn polyester fibers and undrawn polyester fibers as main components. Polyester-mg and unstretched polyester Ill
The embroidery contains acid components such as terephthalic acid, isophthalic acid, oxybenzoic acid, and cepatic acid, and glycol components such as ethylene glycol, propylene glycol, neobenkyl glycol, chlorine glycol, and tetramethylene glycol.
It is a short wire obtained by spinning a polyester obtained by condensation polymerization or copolymerization with a polyester component, stretching it to 10 mA, and cutting it. The mean degree of the stretched polyester is a denier to ti denier, preferably α denier to α denier;
to 3 deniers, preferably (L4 to 2 deniers).The length of the stretched and unstretched 7 jelly ester Ia is suitably about 2 to 1z■.

The paper is broken down and made into paper using conventional papermaking methods, and preferably dried in a Yankee dryer. At this stage, the polyester paper has sufficient strength for winding and processing, but it has not developed the physical properties necessary for the final product, and for paper making.

-Linear polyvinyl alcohol, synthetic polymer f11'#I
It is possible to add a binder such as L or emulsion to papermaking, but this often causes problems with product physical properties such as heat resistance and water resistance, and is likely to cause process troubles, so this is usually not the case. It is not recommended to use other binders.

In the present invention, the polyester paper is a stretched polyester paper.
The paper is made using embroidery and unstretched polyester #11 as the main fiber. The blend ratio of stretched bobbin 11 ester embroidery is 30 to 9
0% is preferable, and the blending ratio of unstretched Bolz Stell Hekihime is 1
0 to 70% is preferred. If the blending ratio of undrawn polyester fibers is too small, sufficient strength cannot be obtained, and if the blending ratio of polyester fibers (drawn yarn) is too small, the paper after heat-pressing and heat treatment will be hard <4. I become dull. In some cases, the polyester paper of the present invention may also contain up to 15% of other il fibers or pulps.

It may also contain particulate matter and other solid matter.

That is, it may contain inorganic embroidery such as glass fiber, bulbs such as polyester or aromatic polyamide, additives such as nizing agents, and other solid substances.

In the Ilc of the present invention, the birefringence index of the undrawn polyester kIi fiber is preferably 030 or less, and (L(1
It is more preferable that the number is one or less.

In the present invention, the polyester paper is subjected to paper bale heat pressure processing,
Then it is heat treated. Heat pressure processing.

The heat-pressing processing temperature is 50°C or more higher than the glass transition point temperature of undrawn polyester fiber and lower than the melting point, and the heat-processing temperature is the same as the heat-pressing temperature. It is necessary that the temperature is higher than the processing temperature and lower than the melting point.The melting point here refers to the melting point of the lower of stretched polyester III fibers and unstretched polyester fibers. If it is lower than the glass transition point of the fabric + 50℃, the paper strength and heat resistance will be poor, and if it exceeds the melting point, a melt layer will occur, so it is not suitable. If the temperature is too low, the strength and heat resistance of the paper will decrease, while if it exceeds the melting point, it will become stiff, so this must be avoided.Heat treatment is carried out in a constant length or tension (stretching) state.

Free shrinkage heat treatment may also be performed.

The polyester paper obtained by the method of the present invention has excellent heat resistance, and is particularly excellent in dimensional stability in a high temperature range and heat deterioration resistance in a medium temperature range. As mentioned above, such excellent heat resistance can be obtained by forming drawn polyester #I fibers and undrawn polyester fibers, subjecting them to hot pressure processing, and heat treatment. Only through this combination can polyester paper with high strength and excellent heat resistance be obtained.

The polyester paper of the present invention has excellent strength and heat resistance as described above, and therefore can be used for insulating materials and various base materials, particularly electrical insulating paper, adhesive paper, flexible printed circuit boards, etc.

The method of the present invention will be explained in detail with reference to examples below, and the method for adjusting the characteristic values of the paper used in the examples is as follows.

Resistance l511 degrees: zso′c, x*o℃M! Hill 'I
Expose the sample paper while opening for deterioration with O'CK setting,
The exposure time until the elongation decreases to SO% of the elongation before exposure to heat is plotted on a graph with the logarithm of 1 hour on the vertical axis and the reciprocal of the absolute temperature on the horizontal axis, and the minimum of 3 points is calculated. The humidity t was extrapolated from the square method for 20,000 hours, and was defined as the S lag resistance at the end of the sample. These steps are explained in IE CPubli
Compliant with cationSSk. A high heat resistance temperature indicates good heat resistance.

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

Example: Unstretched polyethylene terephthalate spun using a conventional method! Lid, fiber 6M, birefringence 010.
Glass transition temperature @9℃, melting point 2aO℃) and this
Double-stretched polyethylene terephthalate fiber ((L
! 1 d@, Panzen Hs Uta was also made into paper using a square sheet machine with a basis weight of 401/wl, and dried in a drum dryer at a surface temperature of 110°C.

The obtained sheet was passed through a double-sided heating calender sealing machine consisting of metal rolls. Calendar cool linear pressure is 200k
It was 1/cm. After calendering, the obtained sheet was subjected to fixed length heat treatment for 3 minutes.

The following table shows the blending ratio of stretched polyester embroidery and unstretched polyester, processing conditions (calendar roll surface temperature and heat treatment temperature), and characteristic values of the obtained paper.

Stretched polyester II with 1 GG% embroidery had poor shadow retention properties after drying with sand paper and could not be formed into a sheet, but sheets were obtained with the others.

Mainly made of unstretched polyester am and polyester
42 to 1 5'b with low calendering temperature /i63 has low strength, and 44 with low heat treatment temperature has low heat resistance and high oil immersion shrinkage rate. All made only of undrawn polyester fiber is Heat resistance is extremely poor. On the other hand, all of the samples 42.4s to 10 produced by the method of the present invention exhibited good heat resistance and high strength.

Patent applicant: Teijin Limited, -

Claims (1)

[Scope of Claims] L (L1 to L5 denier stretched ester embroidery and α bulk to 3 denier unstretched polyester film as the main line aperture, paper-making, drying sheet of the unstretched polyester--glass) Polyester paper with excellent heat resistance characterized by being heat-pressed at a temperature 50°C higher than the transition point and lower than the melting point, and then heat-treated at a temperature higher than the temperature of the heat-pressing process (lower than the melting point) 2. The blending ratio of 1 m of stretched polyester slI is 30 to 9.
0%, the blending ratio of undrawn polyester wire is 10 to 10
%, the method according to claim 1. 1 Birefringence of undrawn polyester l1m fiber is 0Loa
The manufacturing method according to claim gt or sosetsu, which is less than or equal to o. 4. The manufacturing method according to claim 1, stripes 1 or 3, wherein the heat treatment after hot-pressure processing is a constant length or tension JA field.