JPH10130389A - Polyphenylene sulfide film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing polyphenylene sulfide film having good qualities with a high Young's modules and little surface defects, oligomers and uneven thickness by finding a liquid crystalline polymer having improving effects both in fluidity and mechanical characteristics. SOLUTION: This polyphenylene sulfide film consists of a polyphenylene surfide (A) and a liquid crystalline polymer (B) having 0.1-50 Pa.second melt viscosity. The polyphenylene sulfide film is produced by blending the polyphenylene sulfide (A) with the liquid crystalline polymer (B) having 0.1-50 Pa.second melt viscosity and bringing the mixture to form a film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a film obtained by greatly improving the quality and physical properties of a conventional polyphenylene sulfide film. More specifically, the present invention relates to a film having a high Young's modulus, toughness, and streak-like surface defects and uneven thickness. The present invention relates to a polyphenylene sulfide film which is low in electrical characteristics and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Polyphenylene sulfide film is
Utilizing excellent heat resistance and hydrolysis resistance, it is used as a class F insulating thin film material in various electronic devices and electronic component fields. However, since a high-molecular-weight polyphenylene sulfide having a weight-average molecular weight (Mw) of 30,000 or more, which can be practically used, has a high melt viscosity, it is difficult to perform melt extrusion at a high discharge rate to increase productivity, and it is not easy to increase the productivity. There are problems in film production such as surface defects easily occurring and large thickness unevenness. Further, if the molecular orientation is excessively increased in order to improve the mechanical properties such as the Young's modulus, there is a problem that voids are generated at the time of stretching and the film is frequently broken.

[0003] From these facts, recently, in order to improve the fluidity and mechanical properties of the polymer, Japanese Patent Publication No. 3-451
07, JP-A-4-353561, JP-A-5-86
As typified by Japanese Patent Publication No. 266/266, studies have been made to add a liquid crystalline polymer to polyphenylene sulfide. However, known liquid crystalline polymers do not have a sufficient fluidity improving effect, and thus cannot solve the above-mentioned problems relating to the productivity and quality of polyphenylene sulfide.

If the liquid crystalline polymer is fibrous, the improvement in Young's modulus is remarkable.
No. 7577, it is reported that the shear rate is 2
Liquid crystal polyester melt immediately after extruded from 00 ^seconds-1 higher than the extruder to provide a shear rate often take a fibrous form, but then, for example, 10 seconds ^over the shear rate and the like to pass through the filter ^When it is reduced to ¹ or less, even if the fiber shape is immediately after extrusion, the shape is changed to a spherical shape, and as a result, there is a problem that the expected Young's modulus is not improved as much as expected.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to find a liquid crystalline polymer which overcomes the above-mentioned problems of the prior art and which has both an effect of improving fluidity and mechanical properties. An object of the present invention is to provide a high-quality polyphenylene sulfide film having less oligomer and thickness unevenness and a method for producing the same.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventors have intensively studied additives for improving the flowability of polyphenylene sulfide. As a result, when a specific liquid crystalline polymer having an extremely low melt viscosity is added, the flowability of polyphenylene sulfide is greatly improved and the productivity of the film is improved, and the accuracy of filter filtration used in the melt extrusion process is improved. As the die swell becomes smaller, the streak-shaped surface defects are drastically reduced, and the amount of oligomers and fish eyes in the film is reduced due to the suppression of shear heat generation in the extruder. The L / D of the dispersion domain shape of the liquid crystalline polymer can be easily adjusted and the thickness unevenness can be improved, as compared with the case where an existing liquid crystalline polymer is added.
Increased, and the Young's modulus of the polyphenylene sulfide film was improved, and the present invention was completed. That is, in the present invention, polyphenylene sulfide and a polyphenylene sulfide film made of a liquid crystalline polymer having a melt viscosity of 0.1 to 50 Pa · sec, and polyphenylene sulfide (A), and a melt viscosity of 0.1 to 50 Pa · sec. The main feature is a method for producing a polyphenylene sulfide film, which comprises forming a film by blending a liquid crystal polymer (B).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystalline polymer (B) used in the present invention is a polyester or polyester amide having a mesogen group in the main chain, which is melt-moldable and has a liquid crystal forming property. For example, polyesters forming an anisotropic molten phase composed of structural units selected from aromatic oxycarbonyl units, aromatic dioxy units, aromatic dicarbonyl units, alkylenedioxy units, and the like.

Examples of preferred liquid crystalline polymers for use in the present invention include liquid crystalline polyesters comprising the following structural units (I), (II) and (IV), and structures of (I), (III) and (IV) Liquid crystalline polyester consisting of units,
One or more types selected from liquid crystalline polyesters comprising the structural units of (I), (II), (III) and (IV).

[0009]

Embedded image (However, R ₁ in the formula is

Embedded image And R ₂ is

Embedded image R ₃ represents one or more groups selected from

Embedded image Represents one or more groups selected from In the formula, X represents a hydrogen atom or a chlorine atom, and the structural unit [(II) + (III
)] And the structural unit (IV) are substantially equimolar. The above structural unit (I) is composed of p-hydroxybenzoic acid and / or
Or a structural unit of a polyester formed from 6-hydroxy-2 naphthoic acid, wherein the structural unit (II) is 4, 4 ′
Dihydroxybiphenyl, 3,3 ′, 5,5′-tetramethyl-4,4 ′ dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, phenylhydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, Structural units formed from aromatic dihydroxy compounds selected from 2,2'-bis (4-hydroxyphenyl) propane and 4,4'-dihydroxydiphenyl ether; structural unit (III) represents structural units formed from ethylene glycol; Structural unit (IV)
Is terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6 naphthalenedicarboxylic acid,
From aromatic dicarboxylic acids selected from 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and 4,4'-diphenyletherdicarboxylic acid Each of the generated structural units is shown.

In the case of a liquid crystalline polyester comprising the above structural units (I), (II) and (IV), R ₁ is

Embedded image And R ₂ is

Embedded image And at least one selected from the R ₃

Embedded image Those which are at least one kind selected from

In the case of a liquid crystalline polyester comprising the structural units (I), (III) and (IV), R ₁ is

Embedded image And R ₃ is

Embedded image Is particularly preferred.

The structural units (I), (II) and (II)
In the case of a liquid crystalline polyester comprising I) and (IV), R ₁ is

Embedded image And R ₂ is

Embedded image And R ₃ is

Embedded image Is particularly preferred.

The copolymerization amount of the above structural units (I), (II), (III) and (IV) is arbitrary, but from the viewpoints of fluidity, mechanical properties, fine dispersibility and transparency of the film, The copolymerization amount is preferred.

The above structural units (I), (II) and (IV)
In the case of a liquid crystalline polyester consisting of: the structural unit (I) is preferably from 5 to 95 mol% of [(I) + (II)], more preferably from 30 to 90 mol%, and more preferably from 50 to 85 mol%. Most preferred. Structural unit (IV) is structural unit (II)
And are substantially equimolar.

In the case of a liquid crystalline polyester comprising the structural units (I), (III) and (IV), the structural unit (I) is 5 to 95 mol% of [(I) + (III)].
Is preferably 30 to 90 mol%, more preferably 50 to 90 mol%.
85 mol% is most preferred. The structural unit (IV) is substantially equimolar to the structural unit (III).

Further, the structural units (I), (II),
In the case of the liquid crystalline polyester composed of (III) and (IV), the molar fraction of [(I) + (II)] with respect to the structural unit [(I) + (II) + (III)] is 5-95. Mol% is preferable, 30 to 90% is more preferable, and 50 to 85%
Is most preferred. In addition, the structural unit [(I) + (II) +
(III)] is preferably from 5 to 95 mol%, more preferably from 10 to 70 mol%,
~ 50 mol% is most preferred. In addition, structural unit (I) /
The molar ratio of (II) is preferably 75/25 from the viewpoint of fluidity.
９５95/5, more preferably 78/22 to 93 /.
7 The number of moles of the structural unit (IV) is substantially equal to the total number of moles of the structural unit [(II) + (III)].

The term "substantially" in the above description means that the number of the terminal groups of the polyester can be increased to either the carboxyl group terminal or the hydroxyl terminal group, if necessary. This is because the number of moles of the structural unit (IV) is not completely equal to the total number of moles of the structural unit [(II) + (III)].

In the polycondensation of the preferred liquid crystalline polyester, 3,3'-diphenyldicarboxylic acid, 2,2,
'Aromatic dicarboxylic acids such as diphenyldicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecandioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, methylhydroquinone, Aromatic diols such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, 1,4-butanediol,
1,6-hexanediol, neopentyl glycol,
Aliphatic, alicyclic diols such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and m
Aromatic hydroxycarboxylic acids such as 2-hydroxybenzoic acid, 2,6-hydroxynaphthoic acid, and p-aminophenol, p-aminobenzoic acid, and the like can be further copolymerized in a small proportion that does not impair the object of the present invention. it can.

The method for producing the liquid crystalline polyester used in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method.

For example, in the above-mentioned method for producing a liquid crystalline polyester which is preferably used, the structural unit (III)
When the compound does not contain (1) and (2), the following (3) production method is preferable when the compound contains the structural unit (III).

(1) p-acetoxybenzoic acid and 4,
A method of producing from a diacylated product of an aromatic dihydroxy compound such as 4'diacetoxybiphenyl and 4,4'diacetoxybenzene and an aromatic dicarboxylic acid such as terephthalic acid by a deacetic acid polycondensation reaction.

(2) p-hydroxybenzoic acid and 4,
A method of reacting an aromatic dihydroxy compound such as 4'-dihydroxybiphenyl and hydroquinone, and an aromatic dicarboxylic acid such as terephthalic acid with acetic anhydride to acylate a phenolic hydroxyl group, followed by a deacetic acid polycondensation reaction.

(3) In the presence of bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid such as a polymer or oligomer of a polyester such as polyethylene terephthalate or an aromatic dicarboxylic acid such as bis (β-hydroxyethyl) terephthalate. The method of manufacturing by the method of.

Although these polycondensation reactions proceed without a catalyst, it is sometimes preferable to add a metal compound such as stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, and metallic magnesium. .

[0025] The melt viscosity referred to in the present invention, 305 ° C., under a shear rate of 200 ^sec-1, diameter 1 mm, length 20mm
2 is a value measured by a capillary viscometer using a capillary. In the present invention, a liquid crystal polymer having a low viscosity, that is, a liquid crystal polymer which increases the melt viscosity ratio (melt viscosity of polyphenylene sulfide (η _A ) / melt viscosity of liquid crystal polymer (η _B )) is preferable. This is because the object of the present invention can be more effectively achieved when a low-viscosity liquid crystal polymer is added to polyphenylene sulfide. The melt viscosity ratio is desirably at least 5 or more, preferably 10 or more, more preferably 50 or more, and particularly preferably 500 or more. According to the findings of the present inventors, 500 to 100,000 is most preferable.
Therefore, the melt viscosity of the liquid crystal polymer, although it depends on the melt viscosity of the polyphenylene sulfide to be used, 305 ° C., under the conditions of a shear rate of 200 ^sec-1, is preferably a 0.1～50Pa · sec, preferably 0.3-10Pa ・
Seconds, more preferably 0.5 to 3 Pa · s or less.
By adding an appropriate amount of such an ultra-low-viscosity liquid crystalline polymer to polyphenylene sulfide, the fluidity of the molten polyphenylene sulfide is improved, the driving current of the extruder is greatly reduced, and high discharge can be achieved. In addition, due to the effect of improving fluidity, streak-like surface defects and fish eyes are unlikely to occur, and the oligomer amount is 0.05 to 0.3% by weight.
A high-quality polyphenylene sulfide film having a small thickness unevenness and a small unevenness can be obtained. Here, the preferable range of the amount of the oligomer is 0.05 to 0.25% by weight, and more preferably 0.05 to 0.20% by weight.

The amount of the liquid crystalline polymer is not particularly limited, but is 0.01 to 40% by weight, preferably 0.1 to 20% by weight, more preferably 0.5 to 5% by weight based on the total weight of the polymer.
The range of weight% is good. If the amount is less than 0.01% by weight, it is difficult to achieve the object of the present invention. If the amount exceeds 40% by weight, the surface of the polyphenylene sulfide film becomes extremely rough, which is not preferable.

The dispersion form of the liquid crystalline polymer in the polyphenylene sulfide film may be any form such as a skin-core type, a sea-island type, a multilayer type and a fiber type, and is not particularly limited. Is preferably finely dispersed in a polyphenylene sulfide film in a fibrous or oval shape. Here, the average dispersion diameter of the domains of the liquid crystalline polymer is 2 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.2 μm or less. Further, when the aspect ratio (L / D: length L of the longest direction and length D of the longest direction orthogonal to the direction, la / lb) of the domain of the liquid crystalline polymer is 10 to 1000, , The improvement of mechanical properties such as Young's modulus becomes remarkable,
700, more preferably 100 to 500.

The polyphenylene sulfide (A) referred to in the present invention is poly-p-phenylene sulfide (hereinafter, referred to as polyphenylene sulfide).
PPS), and a composition containing 70% by weight or more of poly-p-phenylene sulfide is within the scope of the present invention. Poly p-phenylene sulfide is 70
If the amount is less than the weight percentage, heat resistance, frequency characteristics, temperature characteristics, and the like, which are characteristics of a film made of the composition, are impaired. 30
If it is less than% by weight, other resin compositions and various additives can be contained. Here, poly-p-phenylene sulfide refers to a polymer in which 70 mol% or more, preferably 85 mol% or more of the repeating units are composed of p-phenylene sulfide units. If the content of such a component is less than 70 mol%, the crystallinity and transition temperature of the polymer will be low, and the heat resistance, dimensional stability, mechanical properties and the like, which are characteristics of a film composed of a tree composition containing PPS as a main component, will be impaired. . If the content of the repeating unit is less than 30 mol%, other polymerizable units in the PPS, for example, m-phenylene sulfide,
o-Phenylene sulfide, 2,6 naphthalene sulfide and a part of each aromatic ring thereof have F, Cl, Br, CH
A copolymerizable arylene sulfide unit into which a substituent such as 3 is introduced may be included. The PPS composition may be a homopolymer, a random copolymer, a block copolymer, a linear, branched, or crosslinked type, or a mixture thereof.

The melt viscosity of polyphenylene sulfide of the present invention, 305 ° C., of 200 seconds ^-1 at a shear rate of 50 to 10
The range of 000 Pa · sec is preferable because the heat resistance, dimensional stability, mechanical properties and thickness unevenness of the film are improved. If the melt viscosity is less than 50 Pa · sec, the effect of improving the fluidity by adding the liquid crystalline polymer is small, and if it exceeds 10,000 Pa · sec, the melt viscosity is extremely high, and discharge unevenness and stretching unevenness occur. It is not preferable because it becomes easy. More preferred melt viscosity is 100-2000
Pa · sec, more preferably 200 to 1500P
a · sec. When the melt viscosity of polyphenylene sulfide is large, the melt viscosity ratio (η _A / η _B ) becomes large, and as a result, the flowability of molten polyphenylene sulfide can be effectively improved by adding a liquid crystalline polymer.
Further, in this case, the liquid crystalline polymer is finely dispersed in the film, and the L / D of the liquid crystalline polyester domain formed at this time is also increased. Therefore, the Young's modulus of the film is increased, and the polyphenylene sulfide film of the present invention is used. It is preferable for obtaining. When the melting point of polyphenylene sulfide is equal to or higher than that of the liquid crystalline polymer, the liquid crystalline polymer is easily finely dispersed in the polyphenylene sulfide into a fibrous or oval shape having a large L / D, and the average dispersion diameter is reduced. Therefore, it is preferable.

Such polyphenylene sulfide can be produced, for example, by reacting (1) a halogen-substituted aromatic compound with an alkali sulfide (US Pat. No. 2,513,188, JP-B-44).
-27671 and JP-B-45-3368),
(2) Condensation reaction of thiophenols in the presence of an alkali catalyst or copper salt (see US Pat. No. 3,274,165, British Patent No. 1160660); (3) Coexistence of aromatic compound with sulfur chloride in Lewis acid catalyst Condensation reaction (Japanese Patent Publication No. 46-27255, Belgian Patent No. 2)
And the like, and can be arbitrarily selected according to the purpose.

The polyester film of the present invention contains a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, an ultraviolet stabilizer, as long as the effects of the present invention are not impaired, in addition to polyphenylene sulfide and a liquid crystal polymer. , A lubricant, an antistatic agent, a whitening agent, a coloring agent, a conductive agent and a rust preventive may be added.

Although the polyphenylene sulfide film of the present invention may be a single film, another polymer layer, for example, polyester, polyolefin, polyamide, polyvinylidene chloride, acrylic polymer or the like may be laminated thereon. Especially when the polyester layer is laminated thinly on the surface layer,
The thickness (M) of the laminated portion is made smaller than the average diameter (N) of the particles contained in the laminated portion (M <N), preferably 1/1000 to 1/2 of M, more preferably , 1
By setting the ratio to / 100 to 1/10, it is possible to obtain a film having excellent running properties, slipperiness, and smoothness. In the case of a laminated film, productivity and quality can be improved by mixing a recovered material and the like in the center layer. Examples of such particles include spherical silica (colloidal silica), dry silica, wet silica, alumina, calcium carbonate, titanium oxide, aluminum silicate, barium sulfate, and other minerals, metals, metal oxides, metal salts, divinylbenzene / Examples include, but are not limited to, styrene copolymerized (crosslinked) products, polymer fine particles such as polyimide, silicone resin, and crosslinked polystyrene, mica, talc, and kaolin. In addition, these fine particles can be used alone or in combination.

The polyphenylene sulfide film of the present invention may be an unstretched or unoriented film, but may be formed into a uniaxially or biaxially stretched and heat-fixed oriented film by a known method to obtain physical properties such as heat resistance and mechanical properties. The effect is more remarkably exhibited. As for the biaxial stretching, any of a sequential biaxial stretching method and a simultaneous biaxial stretching method is preferably used.

Next, a method for producing the polyphenylene sulfide film of the present invention will be described, but it is not limited to such an example. Here, an example in which a liquid crystalline polyester is used as the liquid crystalline polymer will be described below.

As described above, the method for producing the polyphenylene sulfide polymer itself is well known in this field, and any method can be adopted. Alkali sulfide and p-
A method of reacting dihalobenzene in a polar solvent under high temperature and high pressure is preferable. In particular, it is preferable to react sodium sulfide with p-dichlorobenzene in an amide polar solvent such as N-methyl-2-pyrrolidone. In this case, in order to adjust the degree of polymerization, it is most preferable to add a so-called polymerization aid such as caustic alkali or alkali metal carboxylate and react at 230 to 280 ° C. The pressure and the polymerization time in the polymerization system are appropriately determined depending on the type and amount of the auxiliary agent used, the desired degree of polymerization, and the like. The degree of polymerization is set to be at least 5 times the melt viscosity of the liquid crystalline polyester (B) to be blended. To rise. After completion of the polymerization, the system is gradually cooled to precipitate the polymer, and the slurry formed in water is separated by filtration, washed with water and dried to obtain poly (p-phenylene sulfide) powder.

Next, the polyphenylene sulfide (A)
, A raw material obtained by blending the above and a liquid crystalline polymer (B), a raw material obtained by once melting and uniformly mixing the raw material, and a raw material obtained by collecting the raw material of the film of the present invention alone or appropriately mixing the above two or three types of raw materials Is supplied to an extruder heated to 310 ° C., and a known method (for example, JP-A-55-111) is used.
No. 235 etc.). Of course, this time, the shear rate of the extruder is 20 ^sec-1 or more, preferably 5
Dispersion diameter of 0 ^seconds-1 or more and higher is in the extruder of the liquid crystal polymer (B) is preferably Nari small, the shear rate 300 sec
^{It is not} preferable to increase the value to ⁻¹ or more, because the liquid crystalline polyester (B) is liable to be thermally decomposed due to heat generated by shearing. In addition, it is preferable to use a known filter, such as a sintered metal, a porous ceramic, a sand, or a wire mesh, for removing foreign matter. At this time, the shear rate at the time of passing through the filter are those 10 seconds ^-1 or less low, the polyphenylene sulfide alone high pressure during filtration pass, by the addition of the liquid crystalline polymer of the present invention, practically the pressure during filtration Range. Draft ratio when extruding into a sheet by a T die is preferably 10 to 100,
More preferably, the average dispersion diameter of the domains of the liquid crystalline polymer can be reduced to 5 μm or less, and the aspect ratio (L / D) representing the shape can be increased uniformly. Thereafter, the sheet-like cast film is heated by a group of heating rolls at 80 to 120 ° C. and stretched 2 to 7 times in the longitudinal direction in one step or two or more steps. Subsequently, the film is guided in a known tenter and heated in a hot-air atmosphere heated to 80 to 120 ° C. while stretching both ends of the film with clips, and stretched 2 to 6 times in the horizontal direction. Subsequently, the film is heat-set at a temperature of 180 ° C. or more and a melting point or less. The heat fixing may be performed under tension, and in order to further improve the thermal dimensional stability, it is also preferable to relax in the width direction. In addition, if necessary, before heat setting, re-longitudinal stretching and / or re-lateral stretching can be performed. After heat setting, 30 to 120
It is also preferable to heat-set again at 10 ° C. for 10 seconds to 10 days.

[Measurement Method of Physical Properties and Evaluation Method of Effect] (1) Melt Viscosity Using a Koka type flow tester, 305 ° C., shear rate 2
Measure the value at 00 seconds- ¹ . The unit is represented by [Pa · sec].

(2) Young's modulus A width of 10 was measured in a Tensilon type tensile test (manufactured by Orientec).
The sample was set so as to be 100 mm in length and the chuck-to-chuck length was 100 mm, and was subjected to a tensile test at a tensile speed of 200 mm / min in an atmosphere of 23 ° C. and 65% RH.

(3) Fish Eye (FE) A 10 cm 2 film is placed under crossed Nicols polarization, and among the glittering portions having different surrounding colors in the whole image, those having a major axis of 10 μm or more are counted. did. The unit is shown in pieces / cm ² .

(4) Amount of Oligomer 100 mg of a film test piece was dissolved in xylene as a solvent for 24 hours.
Soxhlet extraction was performed for a time, and the obtained extract was subjected to liquid chromatography (model 8500, manufactured by VARIAN).
Was measured. The unit is shown in% by weight.

(5) Average Dispersion Diameter and Aspect Ratio of Liquid Crystalline Polymer The polyphenylene sulfide film is cut in the longitudinal, transverse and thickness directions, and the cut surface is observed with a transmission electron microscope. When the domains of the liquid crystalline polymer are spherical, the average dispersion diameter (D) was determined from the average value of 100 domains of the liquid crystalline polymer appearing on these cut surfaces, and the aspect ratio (L / D) was set to 1. . When the domain of the liquid crystalline polymer has an anisotropic shape such as oblate, oval, or fibrous, first, the length in the longest direction (la) is set for each of the 100 domains. And the length (lb) of the longest part orthogonal to it, D is the average value of lb,
L / D was (average value of la) / (average value of lb).

(6) Unevenness of film thickness (%) Film thickness nest tester “KG6” manufactured by Anritsu Corporation
01A "and an electronic micrometer" K306C ", the thickness unevenness in the width direction of the intermediate spool (film having a width of 3 m) after the biaxial stretching and heat treatment is continuously measured. The transport speed of the film during the measurement was 3 m / min. Maximum thickness value Tmax (μm) and minimum value Tmin (μm) for 3 m length
From this, R = Tmax−Tmin was determined, and from R and the average thickness Tave (μm) having a length of 3 m, thickness unevenness (%) = (R / Tave) × 100.

(7) Driving current of the extruder The current was read from an ammeter installed in the extruder. The extruder is a 250 mm single screw extruder equipped with a full flight screw (ratio of screw shaft length / screw shaft diameter = 28, manufactured by Toshiba)
It was used.

(8) Streak-shaped surface defect SKD-61 was used as a base material as a base material, and a portion corresponding to a polymer flow path was subjected to two-step chromium plating (200 μm thick).
m). The base is slit width 2mm, width 1
900mm, T of base material SKD-61 with HRC hardness of 40 degrees
A die die was attached to a 250 mm extruder,
The die temperature is uniformly heated to 310 ° C., and molten polyphenylene sulfide and a liquid crystalline polymer are supplied to the extruder.
After heating and melting to 310 ° C., the melt is extruded from the die,
A cast film is obtained by cooling with a casting drum while applying an electrostatic charge according to a conventional method. Based on the time during which streak-like surface defects appear on the cast film, the state of occurrence of surface defects was classified as follows.

Time from discharge to appearance of streak-like surface defects Symbol Less than 1 day × 1 day or more and less than 3 days ○ 3 days or more ◎

[0046]

EXAMPLES The present invention will be described based on examples and comparative examples.

Example 1 and Comparative Example 1 (Tables 1 and 2) As polyphenylene sulfide, a raw material having a weight average molecular weight of about 60000 and a melt viscosity of 400 Pa · sec was used. As the liquid crystalline polyester, a liquid crystalline polyester (melting point: 265 ° C., liquid crystal starting temperature: 240 ° C., melt viscosity: 1 Pa · sec) polycondensed from the following raw materials was used.

[Liquid Crystalline Polyester A] Copolymerization molar ratio hydroxybenzoic acid 72.5 4,4'-dihydroxybiphenyl 7.5 ethylene glycol 20.0 terephthalic acid 27.5 The polyphenylene sulfide and the liquid crystalline polyester were dried, The mixture was passed through a known 250 m full-flight screw (screw shaft length / screw shaft diameter ratio = 28).
m fed to a single screw extruder at 310 ° C. at a shear rate of 100 seconds
After melt mixing ^metered-1, after the inside of the filter having a 95% cut hole diameter 10μm using metal fibers is passed at a shear rate of 10 seconds ^{over 1,} T-die mouthpiece (slit width 2 mm, width 19
00 mm) and extruded into a sheet at a draft ratio of 20 and then tightly cooled and solidified while applying an electrostatic charge to a casting drum kept at 25 ° C. to obtain a cast film having a thickness of 400 μm (ejection rate 1400 kg / hr). .
The cast film was rolled in a longitudinal roll type stretching machine for 10 minutes.
After stretching 3.7 times at 0 ° C., it was introduced into a tenter,
After stretching 3.5 times at ℃, the film was further heat-treated under tension at 270 ° C. for 10 seconds in a subsequent heat treatment chamber in the same tenter to obtain a 25 μm-thick biaxially oriented polyphenylene sulfide film. Table 1 shows the driving current of the extruder, the state of occurrence of surface defects, and the characteristics of the obtained film during film formation. When 0.5% by weight of the ultra-low viscosity liquid crystal polymer of the present invention was added, the driving current was reduced by about 40% as compared with the case where the polyphenylene sulfide alone was melt-extruded to form a film (Comparative Example 1). No surface defects were observed. Further, the film of the present invention is a high-quality film having a high Young's modulus, a small thickness unevenness, a small amount of fish eyes and oligomers, and has excellent properties as films for various uses such as electric insulation. .

Example 2 and Example 3 (Tables 1 and 2) A biaxially oriented polyphenylene sulfide film was obtained in the same manner as in Example 1 except that polyphenylene sulfide raw materials having different melt viscosities were used. Was. When a raw material having a higher melt viscosity was used, the effect of the present invention became more remarkable.
The average dispersion diameter of the liquid crystalline polyester domain was smaller, the aspect ratio L / D was larger, and a high quality film having a higher Young's modulus than that of Example 1 was obtained. [Example 4] to [Example 7] (Table 1,
2) The melt viscosity and amount of the liquid crystalline polyester used were changed, and a film was formed in the same manner as in Example 1 to obtain a biaxially oriented polyphenylene sulfide film. As shown in Table 2, the lower the melt viscosity of the liquid crystalline polyester, the greater the effect of improving the fluidity of the molten polyphenylene sulfide, and a high Young's modulus and high quality film was obtained.

[Comparative Example 2] and [Comparative Example 3] (Tables 1 and 2) Except that liquid crystalline polyester B having a melt viscosity of 100 Pa · s and liquid crystalline polyester C having a melt viscosity of 300 Pa · s were used as liquid crystal polymers. A film was formed in the same manner as in Example 1 to obtain a biaxially oriented polyphenylene sulfide film. When the melt viscosity is out of the range of the present invention, the effect of improving the flowability of the molten polyphenylene sulfide is insufficient, the driving current of the extruder is reduced only by about 10%, and the streak-like surface defect is discharged after discharge. Occurred in a short time. The quality and physical properties of the obtained polyphenylene sulfide film were not much different from the case of the polyphenylene sulfide alone film of Comparative Example 1.

[Liquid Crystalline Polyester B] Copolymerization molar ratio hydroxybenzoic acid 80.5 4,4′-dihydroxybiphenyl 7.5 ethylene glycol 12.5 terephthalic acid 20.0 [liquid crystalline polyester C] Vectra B950 (polyplastic Made)

[Table 1]

[Table 2]

[0052]

According to the present invention, a film comprising a composite of polyphenylene sulfide and a liquid crystalline polymer having a melt viscosity of 0.1 to 50 Pa · s is intended to improve the productivity of the polyphenylene sulfide film, It is intended to improve Young's modulus, reduce surface defects, oligomers and thickness unevenness, and improve the quality of the film, and can be widely used for various film applications such as electrical insulation.

Claims (10)

[Claims] 1. A polyphenylene sulfide film comprising a polyphenylene sulfide (A) and a liquid crystalline polymer (B) having a melt viscosity of 0.1 to 50 Pa · sec. 2. The polyphenylene sulfide film according to claim 1, wherein a melt viscosity ratio (η _A / η _B ) between said polyphenylene sulfide (A) and said liquid crystalline polymer ( _B ) is 5 or more. 3. The method according to claim 1, wherein the liquid crystalline polymer (B) comprises:
Liquid crystalline polyester comprising structural units of (III) and (IV), liquid crystalline polyester comprising structural units of (I), (II) and (IV), (I), (II), (III) and (IV) 2. The method according to claim 1, wherein the liquid crystalline polyester is at least one selected from the group consisting of liquid crystalline polyesters.
Or the polyphenylene sulfide film according to 2. Embedded image (Where R ₁ in the formula is R ₂ represents one or more groups selected from Represents one or more groups selected from In the formula, X represents a hydrogen atom or a chlorine atom, and the structural unit [(II) + (III
)] And the structural unit (IV) are substantially equimolar. ) 4. The polyphenylene sulfide film according to claim 1, wherein the liquid crystalline polymer (B) is contained in the polyphenylene sulfide film in an amount of 0.01 to 40% by weight. 5. The liquid crystal polymer (B) having an average dispersion diameter of 1
The polyphenylene sulfide film according to any one of claims 1 to 4, wherein the thickness is not more than μm. 6. The liquid crystalline polymer (B) is finely dispersed in a fibrous or oval shape in the film, and the L / D of the fibrous or oval liquid crystalline polymer (B) is 10 or more. The polyphenylene sulfide film according to claim 1, wherein: 7. The amount of oligomer in the film is from 0.05 to
The polyphenylene sulfide film according to any one of claims 1 to 6, wherein the content is 0.3% by weight. 8. The polyphenylene sulfide film according to claim 1, wherein the polyphenylene sulfide (A) has a melt viscosity of 50 to 10000 Pa · sec. 9. The polyphenylene sulfide film according to claim 1, wherein the polyphenylene sulfide film is a uniaxially or biaxially oriented film. 10. A method for producing a polyphenylene sulfide film, comprising blending a polyphenylene sulfide (A) with a liquid crystalline polymer (B) having a melt viscosity of 0.1 to 50 Pa · sec to form a film.