JPS597020A - Manufacture of poly-p-phenylenesulfide film - Google Patents

Abstract

PURPOSE:To obtain the titled film having a low heat shrinkability and a high crystallinity with good productivity, by heat-treating a biaxially orientated poly- p-phenylenesulfide film at a specified temperature while it is stretched, and then heat-treating the thus treated film under specified conditions. CONSTITUTION:Poly-p-phenylenesulfide is formed into a film under pressure and heating, then after the film is immersed into water to be cooled quickly to obtain a transparent unorientated film, the film is orientated biaxially in longitudinal and lateral directions. Then the biaxially orientated film is heat-treated at a temperature in the range of Tm (Tm stands for the meltin point of the film measured by a differential scanning calorimeter)-350 deg.C while the film is stretched, and then is heat-treated at a temperature in the range of 150-350 deg.C to be shrunk by 20% or less in one direction or two directions, or shrunk or stretched by 25% or more in two directions or while the length is kept constant, so that the intended film is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a poly p-phenylene sulfide film, and particularly relates to a method for producing a poly p-phenylene sulfide film that has a high degree of crystallinity and a low heat shrinkage rate. be.

Conventionally, polyethylene terephthalate (hereinafter P E 1'
(abbreviated as ) film, which takes advantage of its mechanical properties, dimensional stability, electrical properties, transparency, chemical resistance, etc., to be used in a variety of applications such as insulating films, magnetic tape base films, photographic base films, and packaging films. However, PET film has a drawback in heat resistance, and its continuous use temperature is only 130℃ for heat-resistant types.Polyimide film is superior as a film with excellent heat dissipation properties. Due to its excellent heat resistance, it is used as a material for space and aircraft and as a high-grade electrical insulation film. Due to demands for lighter weight, higher performance, etc., its applications and usage are expanding year by year.However, since this polyimide film is made by solution casting, productivity is low and costs are high. (・
With all the flaws. Therefore, poly p-phenylene sulfide film was proposed as a film that has better heat resistance than PET film and can be melt-molded and has good productivity, as seen in JP-A-54-142275.
Ru. This poly p-phenylene sulfide film has better chemical resistance and heat resistance than PET film, and also has good mechanical properties, making it a film with well-balanced physical properties. Phenylene sulfide has a slow crystallization rate (・), so when it is normally heat-fixed below Tm, the degree of crystallization is low, and the heat shrinkage rate is large. It was necessary to heat-set for a long time, which was disadvantageous for continuous production.

The present inventors focused on this point, and as a result of intensive research, we found that by heat treatment under specific conditions, the degree of crystallinity is high and the heat shrinkage rate is low. The present invention was achieved by discovering that a film with low IC/IC could not be obtained by heat treatment for a short time.

That is, the present invention is a 2i1+ stretched poly p-phenylene sulfide film stretched in two directions (vertical and horizontal) and heat-treated under tension in a temperature range of Tm to 350°C,
There is one direction in the temperature range of 150 to 350 degrees Celsius.
provides a method for producing a poly p-phenylene sulfide film characterized by heat treatment under limited shrinkage or elongation or constant length within 25% in two directions.

The poly p-phenylene sulfide of the present invention is preferably a polymer in which 90 mol% or more of the constituent unit 3ΣS+ is used. Not only does this cause a decrease in dimensional stability, but it also has an adverse effect on dimensional stability. Such poly p-
If phenylene sulfide is less than 10 mol%, it can be used, for example, as a meta-bond biphenyl bond (%◇-@-S ->, a naphthalene bond (-(S1-S-)), a sulfone bond (忰O
3(〈ΣS −), substituted phenylene sulfide bond ((
0Σ=8-1 where R is alkyl, nitro, phenyl,
It may contain alkoxy, sulfone, halogen, carboxylic acid, metal salt of carboxylic acid, etc.), group, and the above-mentioned trifunctional fluorinated nylene sulfide bond (-).

Poly p-phenylene sulfide is formed into a sheet or film using an extruder or press, and then quenched using liquid nitrogen, water, a roll, etc. to a density of 1.6~OS/2. As a result, an almost amorphous unstretched film is obtained. When crystallization of the unstretched film progresses to .degree. C., the stretchability h'' decreases and the film becomes more likely to break during stretching.

The stretching temperature for an unstretched film varies somewhat depending on the polymer molecules and components, but it is usually desirable to be near the glass transition temperature of the polymer. Specifically, the temperature is 80 to 120°C, preferably 90 to 110°C. Commonly used stretching methods include the °C roll method, tenter method, and tubular method.
It is convenient to use a stretching method such as a stretching method. The stretching ratio is preferably 2.5 to ZO times, preferably 6.0 to 5.5 times, in view of the physical properties and productivity of the resulting film.Which is used: simultaneous biaxial stretching or sequential biaxial stretching. ～・But it’s okay～・.

The biaxially stretched film obtained in this manner increases the crystallinity without losing transparency, so Tm - 350 ° C.
Preferably, the heat treatment is carried out under tension in a temperature range of Tm-660°C, usually for a time of 120 seconds or less. Here, Tm is the melting point obtained by a differential scanning calorimeter (hereinafter abbreviated as DSC) of the film immediately after biaxial stretching. At this time, if the heat treatment temperature exceeds 350℃, the film will become molten even if the heat treatment time is shortened, and the shape of the film cannot be maintained.
By appropriately adjusting the heat treatment time to within seconds, the film can be heat-set without becoming molten.

Films that have been heat-set in this way may show a large value when the heat shrinkage rate is measured, for example by gradually increasing the temperature from room temperature or by directly contacting the film with high temperature atmospheric pressure, so it may not be used under heating. (・
There are cases.

However, such a film after heat setting is heated to 150℃~3
50℃, preferably 200℃ to 350℃ in one direction (・ is within 25% in two directions, preferably 15%
By appropriately heating within 10 minutes under limited shrinkage or elongation or at a constant length, the thermal shrinkage rate can be reduced and the dimensional stability under heating can be improved.

At this time, if the heat treatment temperature exceeds 350° C., even if the heat treatment time is shortened, the film will remain in a molten state and the film will not be able to maintain its shape. If the heat treatment temperature is 350'C or less, a suitable degree of heat treatment can be achieved within a heat treatment time of 10 minutes or less. Also at this time,
If heat treatment is performed in a state that causes shrinkage of 25% or more, the flatness of the film will deteriorate. Further, heat treatment under elongation of 25% or more increases the thermal shrinkage rate of the resulting film. The film heat-treated under pressure may be further heat-treated at 150 to 550° C. under a fixed length if necessary. The heat treatment in the present invention is carried out by bringing the film before heat treatment into contact with a heated gas, liquid or solid. It is also possible to use radiation such as an infrared heater, ultrasonic waves, or high frequency irradiation. In the present invention, the "temperature" and "time" of heat treatment refer to the temperature of the heating medium and the contact time with the heating medium in the case of using a medium, and in the case of using an infrared heater, ultrasonic wave, or high frequency, film temperature and processing time. The film of the present invention obtained by this process has a high degree of crystallinity and excellent dimensional stability under heating, and even when heated to around Tm, it does not cause whitening or tarnishing, and there is no deterioration in physical properties. Sukuna ℃・.

The film of the present invention has excellent heat resistance, dimensional stability, and mechanical properties, and is therefore most suitable as an electrically insulating film or a magnetic recording film. For example, it can be used as a base film for flexible printed wiring boards, insulating materials for various rotating machines such as vehicle motors and refrigerator motors, and various stationary devices, as well as insulating materials for covering general cables, high voltage, and ultra-high voltage cables. It is useful as a base film for magnetic tapes and a film for capacitors. Others, for packaging,
It can be used as a film material for agriculture, photography, adhesive tape bases, building materials, decorations, etc. 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.

Types of physical properties and methods of measuring them in the present invention
It will be described in

(1,1 Glass transition temperature and Tm The glass transition temperature was measured using DSC using the unstretched amorphous film or sheet before stretching, and the Tm was measured using a film immediately after biaxial stretching, respectively, using DSC as the measurement sample (. .

(2) Density and crystallinity (Xc) Density was determined using a lithium bromide aqueous solution at °C using a density gradient tube. The degree of crystallinity (Xe) is determined by the density method using the density described above. In other words, Xe is generally determined by the following equation (11).

In formula (1), d and dcr%dam are the density of the sample, the density of the crystalline phase, and the density of the amorphous phase, respectively. Here, der and dam are Eur, Poly, Jo, and 7.11
27 (1971) and used the value of
= 1.320, lit/cm'.

(3) Heat shrinkage rate The heat shrinkage rate is 5 m in width and 100 m in length of the film after heat setting.
The film was cut out to a length of 50 mm, marked with a 50 mm mark, and kept in a relaxed state for 10 minutes in a dryer kept at a predetermined temperature, and then the distance between the marks was measured.

(4) Tensile test The sample for the tensile test is a film that has been heat-set, cut out into 5 mm width and 100-150 mm length, and heat-treated in a dryer kept at a predetermined temperature for 10 minutes in a relaxed state.
As an evaluation method, the breaking strength (tensile strength), elongation, and F-5 value retention of the film before nuclear heat treatment were determined. The tensile test was carried out using a Tensilon tensile testing machine, where the sample was held with a grip to a sample length of 50 mm and stretched at a tensile rate of 200%/min. At this time, the temperature of the sample was maintained at 23°C.

◎F5 value This is the tensile stress when the elongation of the film is 5% at °C in the tensile test.

(5) Relaxation rate It is expressed as the degree of shrinkage of the film during the second heat setting.

Examples 1 to 6, Comparative Examples 1 to 3 51 1.8 kg of N-methylpyrrolidone in an autoclave
and sodium sulfide 2.7 hydrate O5, sodium benzoate 0.6 yu, and sodium hydroxide 1.6 gk,
Under a nitrogen atmosphere, the temperature was gradually raised to 200°C while stirring for about 2 hours, and 105 d of water was heated to 200°C. I distilled it out. After cooling the reaction system to 170°C, p-dichlorobenzene 0.6
kg and N-methylpyrrolidone 0.4kpk added, 220
The reaction was carried out at 250'C for 2 hours and then at 250'C for 3 hours. The internal pressure at the end of polymerization is 6.7 to 9/crr? Met.

After cooling the reaction system, the contents were separated with P, and the resulting solid content was washed six times with hot water and further twice with acetone, and then heated to 120'
The intrinsic viscosity [η] of this polymer was determined using α-chlornaphthalene at a temperature of 206°C and a concentration of 0.4 g/10 CDl.
When I measured it, it was 061.

This polymer was press-formed at 310'c and then rapidly cooled in water to obtain a transparent unstretched sheet with a thickness of 400 μm. The density of this sheet was t321.9/α3, and it was mostly amorphous. The glass transition temperature or SC of this sheet was measured at a heating rate of 10°C/pnin.
6 at 95°C and then at 95°C.
Simultaneous biaxial stretching of 5×3.5 times was performed. The temperature of this film was measured at 287°C using a TmQ temperature increase rate of 10'C/min. As shown in Table 1, the film of the present invention has a small thermal shrinkage rate, and its physical properties do not deteriorate much even when heated to around Tm.
It was found that it has good heat resistance.

Example 7, Comparative Example 4 Monomer and p-dichlorobenzene 585g, 1,2
Polymerization was carried out under the same conditions as in Examples 1 to 6, except that 2.2 g of 4-trichlorobenzene was used, and a grayish-white, granular polymer was obtained. The intrinsic viscosity [η] of this Porin 5 was measured under the same conditions as in Examples 1 to 3 and was found to be 0.45.

This polymer was press-formed at 610° C. and then rapidly cooled in water to obtain a transparent unstretched sheet with a thickness of 400 μm. The density of this sheet was 1.322 g/lyn'' and was mostly amorphous.

The glass transition temperature of this sheet was measured in the same manner as in Examples 1 to 3 and was found to be 90°C. This unstretched sheet was subjected to sequential biaxial stretching of 3.5 times (MD) x 4.0 times (TD) at 95°C. The Tm of this film was determined in Examples 1 to 3.
When measured in the same manner as above, the temperature was 281°C.

This film was heat-set under tension at 300°C for 20 seconds,
Next, a 5% relaxation treatment was performed at 250°C for 15 seconds.

As a comparative example, after heat setting under tension at 250° C. for 20 seconds, a 5% relaxation treatment was performed at the same temperature for 15 seconds. The physical properties of these films were measured in the same manner as in Examples 1 to 3,
It is shown in Table-2. As shown in Table 2, the film of the present invention was found to have a small thermal shrinkage rate and good heat resistance.

Table 2 Note: Heat shrinkage rate, tensile strength retention rate, elongation retention rate, and F-5 value retention rate were determined using films cut out in the MD force direction and length direction.

Claims (1)

[Claims] A biaxially stretched poly p-phenylene sulfide film that has been stretched and oriented in two directions (vertical and horizontal) is
: Melting point of the film measured by differential scanning calorimeter) ~
Heat treated under tension in a temperature range of 350℃, then
A method for producing a poly p-phenylene sulfide film, characterized in that heat treatment is carried out in a temperature range of 50 to 350'C under limited shrinkage or elongation or constant length within 25% in one direction (.).