JPS58208019A - Heat treatment for poly p-phenylene sulfide film - Google Patents

Abstract

PURPOSE:To obtain the poly p-phenylene sulfide film excellent in sizing stability under heating, in short time required for its thermosetting by heat treating said film drawn in the direction of binary axes at specially determined temperature by two steps. CONSTITUTION:Poly p-phenylene sulfide film drawn and prepared in the two directions of longitudinal and transverse axes is first heat treated at 150-Tm deg.C (Tm is the melting point of poly p-phenylene sulfide film before its heat treatment). Next, the film is heat treated in the range above this first heat treatment temperature and below 350 deg.C at the process of contraction or expansion controlled under 30% in one direction or two directions, or at constant length. Used poly p-phenylene sulfide is the main component of the film, and above 90mol percents thereof is preferably the polymer composed of constructing unit shown by the formula. When said value is less than 90mol percents, the crystal property becomes lower. Then, not only the heat resistive and mechanical properties are lowered, but also harmful effects occur for its sizing stability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for heat treating a poly p-7 2-2lene sulfide film.

Conventionally, polyethylene terephthalate (hereinafter abbreviated as PET) film has been used to make use of its mechanical properties, electrical properties, transparency, chemical resistance, etc., to produce insulation films, magnetic tape base films, capacitor films, packaging films, etc. Used in various fields. However, P
ET film has a drawback in heat resistance, and its continuous use temperature is 160° C. since it is a heat resistant type. Polyimide film is currently available as a heat-resistant film, and due to its excellent heat resistance, it is conveniently used as a material for space and aircraft applications and as a material for high-grade electric wires. Their applications are expanding year by year due to the importance of energy conservation and demands for smaller, lighter weight, higher performance, and improved reliability of various industrial equipment. However, since this polyimide film is made using a bath liquid film forming method, it has the drawbacks of poor productivity and high cost. As a film, there is a poly p-phenylene sulfide film as seen in JP-A-54-142275. However, this film was published in JP-A-56-6212
As seen in No. 1, the heat shrinkage rate is large, and the temperature at 200 °C
Since it shows a heat shrinkage rate of about 1.0 inch, JP-A-55-3
It is necessary to carry out heat setting (same as heat treatment) in two stages as in No. 4967. In this method, 2
The heat setting temperature for the first time is lower than the heat setting temperature for the first time, and the heat setting time is 1 as shown in the example.
The heat setting time is longer than 1 minute, and when combined with the first heat setting time, it requires a very long heat setting time.As a result of intensive research on the fixing method, we found that in a two-step heat setting method, the second heat setting temperature was lower than the first heat setting temperature. It has been discovered that a film with good dimensional stability under knife heat can be obtained in a short heat setting time if heat setting is carried out in a temperature range of 350°C or above, and the present invention has been achieved. be.

That is, the present invention provides two
Axial oriented poly p-phenylene sulfide film t-'1
A polyester characterized by being heat-treated in the range of f150 to Tm °C, and then heat-treated at a temperature range of not less than the heat treatment temperature and not more than 350 °C under limited shrinkage or elongation or constant length within 60% in one or both directions. The present invention relates to a heat treatment method for p-phenylene sulfide film.

The poly p-phenylene sulfide, which is the main component of the film of the present invention, is preferably a polymer in which 90 or more moles of the constituent unit -4-s. This not only causes a decrease in heat resistance and mechanical properties, but also has an adverse effect on dimensional stability.

Such poly p-phenylene sulfides may contain less than 10 moles of nitro, phenyl, alkoxy, sulfone, halogen, hydrocarbon, etc.

As a method for forming a film of such poly p-phenylene sulfide, 1.
Axial stretching method can be applied. That is, known literature (eg, J. Appl.

Polymer Set, 20.2541 H(
(1976), amorphous poly p-phenylene sulfide can be easily obtained by rapidly cooling a melt of poly p-phenylene sulfide, and this non-quality poly p-phenylene sulfide can be converted into A biaxially stretched poly p-phenylene sulfide film can be improved by stretching it simultaneously or sequentially in two directions, longitudinally and transversely, at a temperature above the glass transition temperature and below the crystallization initiation temperature. This biaxially oriented poly p-phenylene sulfide film is almost inferior as it is, and its dimensional stability under heating is poor, making it difficult to use in practice.
Heat treatment under specific conditions is required. That is, a mostly amorphous 2@stretched poly p-phenylene sulfide film is heat treated for crystallization and then further processed in a relaxed or slightly elongated state over a specific temperature range. By being heat-treated, it has excellent dimensional stability under heating. In addition, if the dimensional stability under heating is poor, it becomes unsuitable as a material for precision equipment. Next, a specific film forming method will be described.

Poly p-phenylene sulfide is formed into a sheet or film using an extruder, press, etc., and then rapidly cooled using liquid nitrogen, water, a roll, etc. to a density of 1.33.
0 g/cIL" or less, and an almost amorphous unstretched film is obtained.

If the crystallization of the unstretched film is progressing, the crystal particles will deteriorate the stretchability and the film will be more likely to break during stretching.

Although the stretching temperature of an unstretched film varies somewhat depending on the molecular weight and components of the polymer, it is generally preferable to set the stretching temperature to a temperature range from around the glass transition temperature of the polymer to below the crystallization initiation temperature. Specifically, the temperature is 80 to 120°C, preferably 90 to 110°C. As the stretching method, commonly used stretching methods such as a roll method, a tubular method, and a tenter method can be used. The stretching ratio is preferably 2.5 to 10 times, preferably 6.0 to 5.5 times, in view of the physical properties and main properties of the film, and the stretching methods include simultaneous biaxial stretching and sequential biaxial stretching. Either method may be used, but the film thus biaxially stretched has a temperature of 150 = Tm 'C1, preferably 250 to T to increase the degree of crystallinity.
The heat treatment is usually carried out at m°C for less than 120 seconds. This is referred to as preliminary heat treatment. At this time, it is preferable to heat-treat the film under tension or in a moderately relaxed state in terms of film properties.Films that have been heat-treated in this way can be heated, for example, by gradually increasing the temperature from room temperature, or in a high-temperature atmosphere. If the heat shrinkage rate is measured by a method such as direct contact, it may show a large value and the dimensional stability under heating may be poor. The above-mentioned heat shrinkage can be achieved by heat treatment at a temperature above the heat treatment temperature of 660°C and below 660°C within 60 inches in one or two directions, preferably within 20 degrees, or under a constant length of 180 seconds. It is possible to reduce the heat treatment rate and improve the dimensional stability under heating.This is referred to as the subsequent heat treatment.At this time, the heat treatment temperature is 350'C' (H
If the temperature is exceeded, even if the heat treatment time is shortened, the crystals generated in the previous heat treatment will melt, making it impossible to maintain the shape of the film.

If the heat treatment temperature is 650℃ or less, the heat treatment time is 18
By suitably adjusting the strain within 0 seconds, the heat treatment can be performed without causing melting of the crystals or disturbance of orientation caused by the previous heat treatment. It is surprising that heat treatment is possible even above the Tm of polyp-phenylene sulfide. Further, at this time, if the heat treatment is performed in a state that causes shrinkage of more than 0 degrees, the flatness of the film will deteriorate. If heat treatment is performed under elongation of 60% or more, the film is likely to tear during the heat treatment, and even if the film is well-stretched, the heat shrinkage rate of the film will increase.

In the case of subsequent heat treatment under a fixed length, the heat treatment temperature is preferably 5°C or more higher than the previous heat treatment, and 10°C or more.
It is particularly preferable that the temperature is higher than that. This does not apply when the post-heat treatment is performed under limited shrinkage or elongation.

Most preferably, the first heat treatment is constant length treatment and the second heat treatment is limited shrinkage. In this case, it is also preferable that the post-stage heat treatment temperature is the same as the pre-stage heat treatment temperature. The film heat-treated in this way may be further heated for 15 minutes as needed.
Heat treatment at a temperature of 0 to 650° C. for a fixed length is not a problem.9 The heat treatment in the present invention is carried out by a flow of heated gas or liquid, or by bringing the film before heat treatment into contact with the surface of the solid. Alternatively, radiant heat such as an infrared heater may be used. [The "warm time" and "time" of the heat treatment in the invention of Kueki refer to the temperature of the heating medium and the contact time with the heating medium. The film of the present invention, as described above, has a low thermal shrinkage rate and exhibits a very small dimensional change rate even when left in an atmosphere at 250° C. for 30 minutes.

The film of the present invention has excellent dimensional stability and mechanical properties.
It is most commonly used as an electrical insulation film and a magnetic recording film, as it exhibits heat resistance and electrical properties, and even the slightest dimensional change cannot be ignored. For example, it is useful for flexible printed wiring boards, magnetic tape base films, and capacitor films. In addition, it is used as a heat-resistant insulating film material for the miniaturization and weight reduction of various motors, refrigerator motors, vehicle motors, etc., as insulation insulation for general cables, high voltage or ultra-high voltage cables, and as insulation material for various transformers. It is also useful as diaphragms for batteries. Other uses include packaging, agriculture, photography, adhesive tape bases,
It can be used for building materials, decoration, etc. for example,
Packaging for food, miscellaneous goods, pharmaceuticals, etc. Film for cultivating grass, base film for adhesive or pressure-sensitive tapes coated with adhesive on one or both sides, photographic film, X-ray film, 8mm non-macro film, tracing use. Can be used as a film. It is also possible to use it as a composite material by laminating it with other films or by combining it with metals, paper, etc. The Tm used in the present invention is the biaxially stretched polyp-phenylene sulfide before heat treatment and immediately after stretching. Using a film as a measurement sample and using a differential thermal analyzer or differential scanning calorimeter,
This is the temperature at the peak of the solution peak determined by the usual method.

All examples below are 4f: Examples 1 to 4 are explained in detail.
5. Comparative Examples 1 to 3 kg were charged and heated at 200'C-4 in a nitrogen stream,
Dehydration was performed at a dehydration rate of 55%1. After the system was cooled to 160°C, 0.6 U of p-ntacolbenzene was charged and sealed, the internal pressure was increased to 4 kg/ax'' with nitrogen.The temperature increase rate due to polymerization heat was controlled. te 250
The temperature was raised to 0.degree. C., and polymerization was carried out with stirring for 5 hours. The internal pressure is 1
It had risen to 0klf/ax'. Next, after cooling the system, the pressure was released, and the contents were poured into water to take out the granular polymer, which was washed repeatedly with water and acetone. The polymer was dried at 120'C for 6 hours to form a white, granular polymer. The bath solution viscosity [η] of this polymer was determined to be 0.497100 m1 using α-chlornaphthalene as a solvent. temperature 20
When measured at 6°C, it was found to be 096 di/i. This polymer was pressed into a film at 300° C. and then rapidly cooled in ice water to obtain a transparent, almost amorphous sheet having a density of 4DO microns of 1.3211/cms. This defective sheet is 94
Simultaneous biaxial stretching of 3.5 x 3.5 times was carried out at °C, and further heat-setting was carried out at 270 °C for 2 seconds in Cl2O (preliminary heat treatment) to form a colorless and transparent film of about 63 microns. This film was further subjected to post-stage heat treatment as shown in Table 1. As shown in Table 1, the film according to the present invention has a small thermal shrinkage rate, excellent dimensional stability under heating, and does not change shape even when immersed in solder at 260°C.

The heat yield a in Table 1 is as follows: A film with a width of 10 m and a length of 150 fl with a 100 m marked line in the length direction is left in a dryer at each temperature for 30 minutes in a relaxed state.
The film was taken out from the dryer, the distance between the marked lines was measured, and the shrinkage rate at that time was determined.

No/' Procedural amendment June 9, 1982 Kazuo Wakasugi, Commissioner of the Patent Office1, Indication of the case Patent Application No. 91382 of 19822, Name of the invention Heat treatment method for poly p-phenylene sulfide film 3 , Relationship with the kidney case to be amended Patent issuer 35-58 Sakashita, Itabashi-ku, Tokyo 174 (28
B) Dainippon Ink & Chemicals Co., Ltd. Representative Yo Mura
Kuni Shige, 15 Agent Dainippon Ink & Chemicals Co., Ltd. 2-7-20 Nihonbashi, Chuo-ku, Tokyo 103 Phone: Tokyo (03) 272-4511 (Main representative) 6
, Contents of amendment fil Correct the word ``way'' in line 9 of page 4 of the specification to ``method''.

(2) In the same book, page 12, lines 13-14, [Sodium hydroxide 1.6 kgj is corrected to ``Sodium hydroxide 1.6 gJ.

Claims (1)

[Claims] Biaxially stretched polyimide IJ p- stretched and oriented in two directions, vertical and horizontal.
Phenylene sulfide film is heated to 150℃~Tm
(Tm: The melting point of the biaxially stretched polyp-7 22lene sulfide film before heat treatment is 7,000 degrees Celsius.Then, the melting point of the biaxially stretched polyp-7 22lene sulfide film before heat treatment is 7,000 degrees Celsius.Then, in the warm range above the heat treatment temperature and below 650℃, the film is heated within 60 degrees in one direction or two directions. 1. A method for heat treatment of poly p-7 22lene sulfide film, which comprises heat treatment under limited shrinkage or elongation or constant length.