JPH0788954A - Blended film of polyphenylene sulfide and polyester - Google Patents

Abstract

PURPOSE: To inexpensively obtain a film excellent in strength and high temp. stability by molding a mixture of linear polyphenylene sulfide of which the repeating unit is represented by a specific formula and polyester of which the repeating unit is ethylene terephthalate into an amorphous sheet and stretching this sheet longitudinal and laterally to heat-treat the same. CONSTITUTION: From ten through ninety wt.% of linear polyphenylene sulfide of which the repeating unit is represented by formula and 90-10 wt.% of polyester of which the repeating unit is ethylene terephthalate are mixed to obtain a mixture which is, in turn, melted at 270-320 deg.C to be dispersed and extruded. Thereafter, the extrudate is molded into an amorphous sheet and this sheet is stretched by 2.4-5.4 times in a longitudinal direction at 80-130 deg.C and stretched by 2.5-4.5 times in a lateral direction at 85-140 deg.C to be heat-treated at 180-245 deg.C. In order to easily form a film from this polymerized thermoplastic resin, it is desirable to reduce water content 0.1 wt.% or less through a drying process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blend film of polyphenylene sulfide and polyester, and in particular, it has extremely excellent numerical stability and loss of mechanical strength despite the phase separation between two thermoplastic resins. And a blend film of polyphenylene sulfide and polyester.

[0002]

2. Description of the Related Art Conventionally, a polyester (hereinafter referred to as PET) film represented by polyethylene terephthalate has been used in an extremely wide range because of its excellent properties.

Typical examples thereof include base films for magnetic recording media such as video and audio tapes, base films for electric and electromagnetic parts such as capacitors and motor insulation, base films for packaging, and base films for graphic arts. Is mentioned as an example.

However, with the rapid progress of industrial technology, industrial properties are required to have properties that are difficult to solve with existing PET films alone.

In response to this demand, the use and development of heat-resistant films such as polyimide are expanding.

[0006]

By the way, the polyimide film is expensive as a raw material as compared with its excellent characteristics.
In addition, there is a disadvantage that the cost required for the film forming process is extremely higher than that of the PET film.

[0007] Therefore, there is an interest in developing a film which is relatively cheaper than a polyimide film while having properties superior to those of a PET film.

Typical of these, the repeating unit is

It is a polyphenylene sulfide (hereinafter referred to as PPS) film represented by the following [Chemical formula 1].

[0009] PPS films are highly promising because of their excellent mechanical properties, chemical resistance, electrical properties and the like. However, since the PPS film is expensive as a raw material for its characteristics and the cost in the polymerization step is also high, there remains a problem in expanding various applications.

In order to solve the above problems, in the present invention, after blending PPS and PET,
It is an object of the present invention to produce a film under careful process conditions, and to provide a film which is superior in properties to a PET film but is cheaper than a PPS film.

[0011]

In order to achieve the above object, the present invention has a repeating unit

## STR1 ## Linear polyphenylene sulfide 10
-90% by weight and a repeating unit of 90-10% by weight of polyester typified by ethylene terephthalate are mixed, and the mixture is melted, dispersed and extruded at 270-320 ° C, and then molded into an amorphous sheet. And then 8
After uniaxially stretching 2.5-4.5 times in the machine direction at 0-130 ° C, stretch in the transverse direction 2.5-4.5 times at 85-140 ° C, and heat-treating at 180-245 ° C. Is performed to produce a blend film of polyphenylene sulfide and polyester.

[0012]

EXAMPLES Generally, the repeating unit is

The PPS typified by [Chemical Formula 1] can be roughly classified into two types on the basis of a polymer chain.

The first is produced by pressurizing and heating para-dichlorobenzene and sodium sulfide under a polar solvent to synthesize low molecular weight PPS, and then performing a curing reaction at high temperature and high humidity. The second is a cross-linked PPS, and the second is a high molecular weight linear PPS in which a co-catalyst (a substance that increases the catalytic action) is added when the reaction of para-dichlorobenzene and sodium sulfide is performed. is there.

The PPS used in the present invention is preferably the latter high molecular weight linear PPS.

There are many types of polyesters used to form films. In the present invention, although not particularly limited, it is desirable to use a polyester whose repeating unit is substantially ethylene terephthalate.

Furthermore, since it is difficult to add inorganic particles and other additives to PPS in terms of polymerization characteristics, it is desirable that the inorganic particles and other additives in the present invention be added during PET polymerization.

As described above, the thermoplastic resin or the like polymerized so as to conform to the present invention is melted and formed into a film to facilitate film formation. Therefore, the water content of the thermoplastic resin or the like is dried. It is desirable to remove to 0.1 wt% or less through

There are various methods for drying the water contained in the thermoplastic resin, but industrially, a method of drying by a vacuum batch system, a method of blowing dry air to remove the water, and the like are usually adopted. To be done.

In the present invention, PPS and PET may be mixed at a proper ratio and then dried. Since the two thermoplastic resins have different water absorption amounts and crystallization behaviors, they are respectively dried and then mixed. Good.

The PPS blending ratio is preferably such that the polyphenylene sulfide ratio is in the range of 10-90% by weight, more preferably 20-80% by weight.

If the proportion of PPS exceeds 90% by weight, the properties of PSS dominate the overall properties of the blend film, which is outside the scope of the present invention.

If the proportion of PPS is less than 10% by weight, the properties of PET dominate the overall properties of the blend film, which is outside the scope of the present invention.

Various methods of extrusion can be used for producing the blended film of PPS and PET in the present invention, and the method is not particularly limited, but even if a generally used single screw type melt extruder is used. It doesn't matter.

Here, it is desirable to design the screw so that the two thermoplastic resins are uniformly dispersed.
In particular, it is preferable to design the metering section and the conduit section up to the T-die in detail.

In particular, it is also a preferable method to install a mixer capable of mixing the melted thermoplastic resin at the end of the conduit.

Further, in order to achieve the object of the present invention,
It is necessary to carefully set the temperature of the melt extruder according to the blend ratio.

It is desirable to change the temperature of each part (solid conveying part, pressing part, measuring part) of the melt extruder according to each blending ratio, but the melt extrusion temperature is in the range of 270-320 ° C. Preferably.

More preferably, melt extrusion is performed at 285 to 310 ° C.

If the melt extrusion temperature is lower than 270 ° C., unmelted PPS will be discharged, which is not preferable. At temperatures higher than 320 ° C., decomposition of PPS and PET,
It is not preferable because gelation becomes brittle.

In order to prevent the progress of crystallization and phase separation in the blend of the melt-extruded sheet-like thermoplastic polymer and the like, it is necessary to undergo an appropriate cooling and solidification process.

Many methods have been introduced for the cooling and solidifying process in the film forming process.

Typical examples of the moving cooling body include a method of using a continuously rotating casting drum and a method of using a continuously moving conveyor belt.

Although not particularly limited in the present invention, it is more preferable to use a casting drum. At this time, the surface temperature of the casting drum is 10-8.
It is necessary to bring the temperature to 0 ° C. to suppress crystallization and phase separation.

Further, a method of effectively adhering the sheet-like blend to the casting drum in the cooling and solidifying process is used, and such a cooling and adhering method has been introduced in many documents.

Although not particularly limited in the present invention, the static electricity applying adhesion method described in Japanese Patent Publication No. 37-6142 is more preferable.

Further, in the electrostatic contact method, various methods such as a method of applying a high voltage to the wire electrode, a method of applying a high voltage to the casting drum, a method of using a pin-shaped electrode, a knife edge method and the like are available. It is known.

Although not particularly limited in the present invention, a method of applying a high voltage to a wire electrode of tungsten, molybdenum, stainless steel or the like is used.

In this way, in order to improve the physical properties of the obtained substantially amorphous sheet, it is necessary for the blended product to adopt an appropriate stretching method and be oriented.

Examples of the stretching method include a simultaneous flat biaxial method, a flat successive biaxial method, and a tubular method.

In the present invention, it does not matter which method is adopted, but the flat method sequential biaxial stretching method is more desirable because it is easy to control the quality and economically advantageous.

The flat bi-directional sequential stretching in the present invention is carried out in the initial direction at a temperature of 80-130 ° C. at 2.5-
It is desirable to perform uniaxial stretching to 4.5 times.

By the way, in order to improve the stretchability and the physical properties of the film, 2.8-4.
It is more desirable to stretch the film in the longitudinal direction to 0 times.

The longitudinal stretching in the present invention is performed between rollers having different speeds, and heat may be locally supplied by an infrared heater.

The longitudinally stretched film is preferably conveyed to the inside of the tenter after being cooled to the glass transition temperature (Tg) or lower.

The transverse stretching in the present invention is 85-1.
2.5-4.5 times at 40 ° C, preferably 90-130 ° C
Is preferably 2.8 to 4.2 times.

Films sequentially biaxially stretched in the manner described above should be crystallized by heat so that the orientation produced is not melted.

The preferred heat setting temperature in the present invention is 1
It is in the range of 80-245 ° C.

As described above, since residual stress exists inside the oriented and crystallized film, it is preferable to perform an appropriate heat treatment. The heat treatment can be selected from a tension state, a fixed length state, a relaxation state, and the like.

Although not particularly limited in the present invention, in light of experience, it is desirable that the relaxed state is effective, and that the heat treatment temperature is the same as or slightly lower than the heat setting temperature.

The present invention will be described in more detail below with reference to examples.

Thermoplastic resin used in the examples,
The method for measuring and evaluating the characteristic value of the film is as follows.

(1) Evaluation of linearity of thermoplastic resin: The gel state is examined in a molten state of the thermoplastic resin using a polarizing microscope, and the content of cross-linked polymer or the like is observed.

(2) Intrinsic viscosity of thermoplastic resin: value measured at 25 ° C. with orthochlorophenol.

(3) Thermal shrinkage (%): After being left for 30 minutes in an oven at 150 ° C., the temperature of which is controlled within ± 1.0 ° C., the rate of change (%) in initial length is measured.

(4) Mechanical properties: Measured according to ASTM D882.

Example 1 When a molten state at 300 ° C. was observed with a polarizing microscope, polyphenylene sulfide 75 with minute gel-shaped defects was observed.
Wt% and 0.25 silicon dioxide and calcium carbonate
25% by weight of polyethylene terephthalate having an intrinsic viscosity of 0.64 was dried in a rotary vacuum dryer to a water content of 0.1% by weight or less.
Put in 180 degree rotary vacuum mixer and mix well, then 3
After melting and dispersing using a melt extruder in which a single screw of 5 mmφ is installed and each part of the melt extruder is set to a temperature of 270 to 300 ° C., 3
Extruded in sheet form on a casting drum through a 50 mm wide T-die.

At this time, in order to effectively bring the blend of the sheet-shaped thermoplastic resin into close contact with the drum, a high voltage of 5.0 KV is applied to the tungsten wire electrode to apply static electricity.

The casting drum uses double cooling rollers of 300 mmφ and 260 mmφ having a surface temperature of 30 ° C.

Thus, a flat width of 325 mm, 250 μ
m amorphous sheet is manufactured.

The amorphous sheet was mixed with a preheating roller at 95 ° C. and 3
Due to the difference in rotation speed with the cooling roller at 0 ° C., longitudinal stretching is performed 3.5 times.

Next, after transversely stretching 3.5 times in a tenter at 110 ° C., heat setting and heat treatment are performed at 220 ° C. and 180 ° C. to produce a film of 15 μm.

The blend films according to the invention are listed in Table 1,
As shown in Table 2, despite the phase separation of the two thermoplastic resins, the numerical stability is PE at a high temperature for a long time.
The result is extremely superior to the T film and the loss of mechanical strength is considerably small.

Example 2 Intrinsic viscosity 0.6 charged with 0.25% by weight of polyphenylene sulfide and silicon dioxide and calcium carbonate
4 except that 50% by weight of polyethylene terephthalate, which is 4, is melted and dispersed through a melt extruder set at 265-295 ° C. and then extruded,
The same procedure as in Example 1 is carried out to produce a 15 μm PPS + PET blend film.

The results are shown in Tables 1 and 2.

The numerical stability of the blend film according to Example 2 at high temperature was better than that of Example 1, but the strength was even smaller.

Example 3 25% by weight of polyphenylene sulfide and 75% by weight of polyethylene terephthalate having an intrinsic viscosity of 0.64 charged with 0.25% by weight of silicon dioxide and calcium carbonate were mixed and then set at 260-285 ° C. The same procedure as in Example 1 was repeated except that the mixture was melted and dispersed through an extruder and then extruded.
A PS + PET) blend film was produced.

The results are shown in Tables 1 and 2.

The numerical stability of the blend film according to Example 3 at high temperature was similar to that of Example 1, and the strength showed a smaller result.

Comparative Example 1 Polyphenylene sulfide was mixed with silicon dioxide and sodium stearate at 0.25% by weight, and then 275
After extrusion at a temperature of −305 ° C., a 15 μm PPS-only film was produced in the same procedure as in Example 1.

The results are shown in Tables 1 and 2.

Comparative Example 2 Polyethylene terephthalate having an intrinsic viscosity of 0.64 charged with 0.25% by weight of silicon dioxide and calcium carbonate was extruded at a temperature of 250 to 280 ° C. and then 15 μm in the same procedure as in Example 1. PET-only film was produced.

The results are shown in Tables 1 and 2.

[0073]

EFFECT OF THE INVENTION The blend film produced according to the present invention has a small loss of mechanical strength and numerical stability at high temperature, in spite of the characteristics that two thermoplastic resins such as PPS and PET are phase-separated. Is extremely excellent in

The blended film of PPS and PET having this excellent effect is a base film for capacitors,
It is used as an extremely useful base film in the fields where heat resistance and numerical stability are required, such as general electric insulating base films.

[0075]

[Table 1]

[0076]

[Table 2]

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Claims (1)

[Claims] 1. The repeating unit is: 10-90% by weight of linear polyphenylene sulfide and 90-10% by weight of polyester whose repeating unit is ethylene terephthalate are mixed, and the mixture is melted, dispersed and extruded at 270-320 ° C.,
1. Formed into an amorphous sheet, then at 80-130 ° C
Uniaxially stretched in the machine direction to 5-4.5 times, 85-140
180- after stretching 2.5-4.5 times in the transverse direction at
A blend film of polyphenylene sulfide and polyester, which is heat-treated at 245 ° C.