JPH09278912A - Polyphenylene sulfide film for mold-releasing and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mold-releasing polyphenylene sulfide film for liquid crystal membranes which can improve the surface defects of stripe roughness occurring on the melt molding with excellent heat resistance by arranging a melt-kneading mixer between the filter and the T die. SOLUTION: This film has an average surface roughness of 0.005-0.03μm and the uneven stripes occurring on the film surface having >=0.3μm height from the film base face at a rate of <=12/m, preferably the recurring units of the polyphenylene sulfide polymer comprising more than 98 mol% of the structural units shown by the formula, and the melt viscosity of 1,000-10,000 poise under the shearing rate of' 200 sec<-1> . This polymer is melt-kneaded and filtered through a filter in a melt extruder and extruded out of a die into a sheet, and biaxially oriented to give the objective film. In this process a mixer which can melt-knead the polymer is inserted between the filtration process and the T die.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyphenylene sulfide film, and more particularly to a releasing polyphenylene sulfide film having few surface defects on the film.

[0002]

2. Description of the Related Art With the rapid development of electronic equipment and information equipment, the required level of liquid crystal film and high-performance polymer film has been improved, and the film thickness is extremely thin, homogeneity, and surface property (foreign matter, scratches, unevenness). Required characteristics such as flatness are becoming severe. These functional films are difficult to produce alone, another polymer sheet or film, after coating and solidifying the functional film resin on a metal plate or a glass plate, another polymer sheet or film, Cases manufactured by peeling from metal plates, glass plates, etc. are increasing. In particular, when used for electronic equipment and information equipment, there is often a process such as bonding with other equipment or coating another resin on the functional film, and since it is often continuous processing, the separation Polymer sheets and films are often used as mold materials.

Therefore, the required quality becomes strict for sheets and films used for releasing. In order not to impair the quality of the functional film (hereinafter sometimes referred to as a release film), the surface property and flatness are excellent, and in order to improve workability during processing, heat resistance and Chemical resistance, releasability, mechanical properties, stain resistance (If another release coating is applied to the film surface, the coating may be transferred to the release film at the time of release. There is no such thing).

The following are examples of films and sheets conventionally used in this field.

(1) Polyethylene film, sheet (2) Polypropylene film, sheet (3) Polyester film (4) Polyimide film (5) Fluorine-based film Also, a polyphenylene sulfide film is disclosed in JP-A-53.
-108883, 54-137554, etc. are proposed. In addition, JP-A-7-140326 proposes to use a PPS film as a release base material for a liquid crystal film. Further, the film having improved surface defects and a reduced friction coefficient to improve workability is disclosed in JP-A-55-34968 and 59-19531.
It is proposed in Japanese Patent Publication No. 9 and the like.

[0006]

However, the films and sheets described above have the following problems. (1), (2)
The film and sheet of No. 2 have excellent releasability and chemical resistance, but have a problem with heat resistance. The film of (3) has heat resistance and chemical resistance,
There is a problem in releasability. When the film is used in a release field, a release coating is often applied to the surface of the film, which causes a problem of contamination. Also, it has a heat resistance of 200 ° C.
When it is exposed to a temperature higher than the limit, it shrinks rapidly. Further, the film (4) has high heat resistance, but has problems in chemical resistance (particularly weak in alkali), releasability and film homogeneity. Furthermore, although the film of (5) is excellent in releasability, it has a problem in mechanical properties, and the film is deformed if high tension is applied during processing.

On the other hand, a polyphenylene sulfide film (hereinafter sometimes abbreviated as PPS film) is excellent in heat resistance, chemical resistance, mechanical properties, and releasability, and is most suitable as a release film such as a high-performance film. . However, coarse projections on the surface of the film and streak-like surface defects generated during melt extrusion molding cause surface defects in the release film, and the use in the field of application has been limited. JP-A-55-34968 and JP-A-59-195319 have proposed a method for preventing coarse protrusions on the surface of the film in order to improve surface defects. The unevenness is not improved. In the mold release application of the liquid crystal film proposed in JP-A-7-140326 and the like, there is a problem that the production yield is significantly reduced due to the above-mentioned streaky irregularities.

The present invention provides heat resistance, chemical resistance, mechanical properties,
It is an object of the present invention to provide a high-performance release film in which coarse projections on the surface of a PPS film rich in releasability and the like are reduced and in which streaky irregularities generated on the film surface are improved.

[0009]

That is, the present invention relates to a film having an average surface roughness (Ra) of 0.005 to 0.03 μm, which is 0. 12 streaks-like irregularities of 3 μm or more
It is a polyphenylene sulfide film for release, which is characterized by being m or less.

Further, in the method for producing a biaxially oriented polyphenylene sulfide, which comprises melt-kneading with a melt extruder, filtering, extruding a melt-formed sheet from a T-die, casting, biaxially stretching, and heat-treating, at least the filtration. A method for producing a polyphenylene sulfide film for release as described above, characterized in that a mixer capable of melt-kneading is used between the overstep and the T-die.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the average surface roughness (Ra) means DIN-4768, JIS-B-060.
1 is the average value of the fine irregularities on the film surface, which is measured by the method specified by the standard in 1 etc. and is expressed in μm. The R
a is 0.005 to 0.03 μm (preferably 0.007)
.About.0.025 .mu.m), the workability is poor and surface defects are likely to occur in the release film, so that the object of the present invention cannot be achieved. That is, when the Ra is less than 0.005 μm, a scratch is formed on the film surface when the film is rolled up or passed through a transport roll at the time of manufacturing or processing the film, and the scratch is formed on the release film after release. It will be transcribed. When Ra exceeds 0.03 μm, coarse projections are formed on the surface of the film, causing surface defects in the release film.

In the present invention, the film to be peeled must be 12 / m or less (preferably 10 / m or less) streak-like irregularities of 0.3 μm or more generated on the film surface with respect to the base surface of the film. Streaky defects are generated, and the object of the present invention cannot be achieved. Here, the streaky irregularities mean
It refers to irregularities having a height of 0.3 μm or less and a width of 20 mm or less that continuously appear on the surface of an unstretched film or a biaxially stretched film. The unevenness can be confirmed with the naked eye when reflected light is applied to the unstretched film, and can be confirmed with the naked eye when polarized light is applied to the biaxially stretched film.

Here, the height and width of the unevenness can be quantified by the following method. A filter for extracting only sharp fluctuations is connected to the output of a thickness measuring machine that can continuously measure the film thickness, and a chart recorder is also connected to continuously measure the film thickness in the direction perpendicular to the continuous stripe-shaped irregularities. When measured in detail, a large waviness portion of the thickness pattern can be converted into a linear change, and only a steep change can be represented in the chart. The peaks of the peaks and valleys of this abrupt change are the heights of the streaky irregularities in the present invention. Further, the width of the peaks or valleys at the central portion in the height direction of the peaks and valleys that fluctuate linearly becomes the width of the irregularities. The base surface of the film refers to a straight line drawn in the measurement direction (chart traveling method) at the central portion in the height direction of the peaks and valleys. If the height of the streaky irregularities (the distance from the peaks of the peaks and valleys to the film base) measured by the above method is 0.3 μm or more, surface defects are likely to occur in the release film after release. The width of the streaky irregularities (the variation width in the direction perpendicular to the streaky irregularities) of 20 mm or less hinders the object of the present invention. If it exceeds 20 mm, it will not be a sharp change and the influence on the release film will be small. When the fluctuation is 12 lines / m (preferably 10 lines / m) or more with respect to the measurement direction (direction perpendicular to the streaky irregularities), the surface defects imparted to the release film become remarkable and the object of the present invention can be achieved. Disappear.

The release in the present invention means that a target resin or resin composition is once applied to another base material by a method such as coating or laminating, and then a peeling step is provided at least once to provide the target coating. It means that the release film is obtained by peeling and separating from the other base material, and the base material film used for such an application is called a release film. The thickness of the release film of the present invention is preferably 6 to 350 μm, more preferably 10 to 250.
μm is good in terms of workability.

The polyphenylene sulfide film of the present invention means an unstretched or non-oriented film obtained by melt-molding a PPS resin composition or a biaxially oriented film obtained by biaxially stretching and heat-treating the unstretched film. Biaxially oriented films are particularly preferred for achieving the object of the invention.

PPS means that 90 mol% or more of repeating units have the following structural formula

Embedded image Means a polymer comprising the structural unit represented by When the content of the component is less than 90 mol%, the heat resistance, the dimensional stability, the chemical resistance, the mechanical properties, etc., which are characteristic of the film made of the resin composition containing PPS as a main component, are low in the crystallinity of the polymer, the heat transition temperature, etc. Spoil. Here, a copolymerizable sulfide bond may be contained as long as it is less than 10 mol% of the repeating unit.
In particular, in order to reduce the streaky irregularities generated during the melt molding of the film, which is the object of the present invention, the content of the repeating unit is preferably 98 mol% or more, more preferably 1
It is a polymer composed of 00 mol%.

The resin composition of the present invention means a composition containing 70% by weight or more of PPS. PPS content is 7
If it is less than 0% by weight, heat resistance, mechanical properties, surface properties, etc. are impaired. The remaining less than 30% by weight of the resin composition may contain additives such as polymers other than PPS, inorganic or organic fillers, lubricants, colorants, antioxidants and antistatic agents.

The melt viscosity of the resin composition has a temperature of 300.
700 to ^{1 at} ℃ and shear rate of 200sec ^-1
A range of 5000 poise is preferable from the viewpoint of moldability, but in order to prevent streaky irregularities and other surface defects generated during melt molding, which is the object of the present invention, the melt viscosity is 10
00-10,000 poises are preferable, and 1000-8000 poises are more preferable. The melt viscosity is 100
If it is less than 0 poise, the unstretched film cast by melt molding tends to be crystallized, and it becomes difficult to control the surface morphology of the biaxially stretched film thereafter, and conversely, if it exceeds 10,000 poise, streaky irregularities are likely to occur. The melt viscosity is equal to the melt viscosity of the PPS film finally obtained.

On the surface of the release PPS film of the present invention,
As long as the object of the present invention is not impaired, a resin or compound such as a release agent or an antistatic agent may be applied or laminated, or an appropriate surface treatment such as corona discharge treatment or plasma treatment may be performed.

Next, a method for producing the releasing polyphenylene sulfide film of the present invention will be described.

First, the method for producing PPS used in the present invention can be obtained by reacting an alkali sulfide with paradihalobenzene in a polar solvent at high temperature and high pressure. In particular, it is preferable to react sodium sulfide and paradichlorobenzene in an amide high boiling point polar solvent such as N-methylpydrodone. 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 and alkali metal carboxylate, and react at 230 to 280 ° C. In the PPS used in the present invention, 98 mol% or more of repeating units have the following structural formula:

Embedded image In order to achieve the object of the present invention, it is particularly preferable to use a structural unit represented by the following. Therefore, isomer compounds (trichlorobenzene etc.) in which paradichlorobenzene having the above-mentioned monomer composition is purified and mixed in advance are often removed. Is particularly preferred. The pressure and 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 obtained powdery or granular polymer is washed with water and / or a solvent to separate by-products salt, polymerization aid, unreacted monomer and the like.

A PPS resin composition is produced based on this polymer. First, in order to control the average surface roughness (Ra) of the release PPS film of the present invention within the range of the present invention, an inorganic or organic lubricant is mixed with the above-mentioned powdery or granular polymer, and Henschel or the like is used. After uniform mixing, it is supplied to the extruder and further melt-kneaded, and melt-formed into a gut shape,
A pellet cut into a length of about 2 to 10 mm is prepared. Alternatively, the above lubricant may be supplied to an extruder having a vent structure and melted and kneaded alone. Alternatively, an additive such as a lubricant may be breaded to a higher concentration than the concentration used, and then diluted to an appropriate concentration in the film production process. The lubricant used in the present invention has an average particle size of 3 μm.
In the following, the addition amount of 0.05 to 3% by weight is particularly preferable because it is easy to control the Ra within the range of the present invention. Further, the grain shape is not particularly specified.

Next, the PPS resin composition pellets obtained above are heated at a temperature of 100 to 180 with a heating dryer under vacuum.
Drying is performed at a temperature of about 1 to 5 hours.

The resin composition is melt-molded into a film to obtain an unstretched film. The PPS resin composition is fed to a cylinder part capable of controlling each temperature stepwise, fed to an extruder equipped with a screw that moves while melting, and the polymer exiting the extruder is passed through a short tubular pipe. Lead to the filtration process. The filtration process is a process that removes foreign substances and aggregates of additives contained in the polymer, and a metal filter such as wire mesh, sintered metal, and metal fiber is installed in a case called a filtration box. Has been done. The molten polymer that has passed through the filtration step also passes through the short pipe and has a straight lip.
It is melt-molded into a sheet with a die called a die and discharged from the lip. The polymer discharged in a sheet form is cooled to a temperature not higher than the glass transition point of the polymer and solidified (cast) by a metal roll installed directly below the polymer roll to form an unstretched film (sheet).

Here, with regard to the streaky irregularities generated during melt molding, which is the object of the present invention, it is extremely preferable that the discharge flow rate distribution of the polymer discharged from the lip of the T die is uniform in the width direction of the lip of the T die. is important. The flow rate is determined by the polymer viscosity, the flow velocity distribution of the polymer, etc., the ratio of the polymer flow rate in each width direction to the average polymer flow rate in the width direction of the T die is determined, and the average value is defined as the mouthpiece index. 0.95
If this is not the case, the streaky irregularities referred to in the present invention are concentrated in the central portion of the T-die, and the object of the present invention cannot be achieved. The index can be controlled by optimizing the shape of the many-hold portion of the T die, the lip gap, and the pressure loss. Further, the effect of the present invention is further improved by using a mixer for kneading the molten polymer again between the filtration in the above process and the T die. The mixer is a method of kneading a molten polymer while changing the flow path of the polymer inside the short tube, a method of mechanically mixing from the outside, and the like. It has a function of making uniform.

The unstretched film thus obtained can be further converted into a biaxially stretched film by a known method such as a sequential biaxial stretching method or a simultaneous biaxial stretching method. Stretching is performed at 90 to 110 ° C. in both the longitudinal direction and the width direction for 3 times.
~ 5 times. Further heat treatment is performed. The heat treatment conditions are temperature 180 to melting point, constant length or 15%
It is heat resistant to perform for 1 to 60 seconds under the following restricted shrinkage,
It is preferable in terms of mechanical properties and thermal dimensional stability. Furthermore, in order to improve the thermal dimensional stability of the film, it may be relaxed in one or two directions.

[0027]

[Characteristic Evaluation Method] Next, the characteristic evaluation method and evaluation criteria used in the description of the present invention will be described.

(1) Average surface roughness (Ra) According to DIN-4768, cutoff: 0.25 mm,
Test length: Measured at 2.4 mm. The measurement magnification was set to 20000 times in the vertical direction and 50 times in the horizontal direction. The surface roughness measuring machine used is SE-3F manufactured by Kosaka Laboratory Ltd.

(2) Melt viscosity Using a high-lower type Flotester having a capillary die having a length L and a radius R, the volumetric discharge amount when the polymer is extruded at a pressure P under a temperature T is represented by Q. Then, the apparent shear rate γ and the apparent viscosity μ are defined as follows.

Τ = (RP) / (2L) γ = (4Q) / (πR ² ) μ = τ / γ At this time, a curve μ = f obtained by plotting μ at various times for various γ Of (γ), γ = 200 sec ⁻¹
The melt viscosity is defined by the value at.

In the present invention, L = 10 mm, R = 0.
A value measured at T = 300 ° C. using a 5 mm die was used.

(3) Streaky unevenness The film automatic feeder used is an Anritsu film feeder, and the thickness gauge is K306 manufactured by Anritsu Corporation.
C was used.

The filter is KZ-made by KEYENCE.
U3 and the recorder used RD-50R by KEYENCE.

The chart recorder is PEN manufactured by Yokogawa.
RECORDER type 3056 was used.

The measuring condition is that the film feeding speed is 60 cm.
/ Min, and the chart speed was 20 cm / min.

(4) Measurement of streak-like surface defects of the film to be released The surface of the film was rubbed with a cloth, and the film was treated with a method as described in JP-A-7-14.
The liquid crystal polymer described in Example of Japanese Patent No. 0326 was prepared, applied, dried, and heat-treated, and then the film was peeled from the film, sandwiched between glass plates, and the streaky surface defects of the film were confirmed by polarized light. The evaluation was carried out according to the following criteria, and Δ or more was defined as a pass range. The evaluation sample size is 300 mm × 20
0 mm.

The drying temperature of the applied liquid crystal polymer is 1
It was carried out at 00 ° C. for about 10 minutes. The heat treatment condition is 23
It was carried out at a temperature of 0 ° C. for about 30 minutes.

⊚: Almost no defects in the release film ◯: Some defects in the release film (thin defects in 1 to 2 places) Δ: 2 to 6 defects in the release film However, the defect portion is thin. ×: Most of the defects are dark in the number of defects in the released film of 5 or more. ×: The number of defects in the released film is almost all over the surface, and the defects are dark.

(5) Measurement of surface defects other than streaks on the release film The surface defects other than streaks were confirmed by the same method as in (4) above, and evaluated according to the following criteria. It should be noted that Δ or more was set as the acceptable range.

⊚: Almost no defects in the release film ◯: Some defects (1 to 3) in the release film Δ: 2 to 6 defects in the release film ×: Release Large defects coexist at 6 or more defects in the mold film XX: The number of defects in the released film is almost all over the surface, and many large defects are present.

(6) Tensile test (strength, elongation) The film was measured only in the longitudinal direction according to the ASTM-D-638-72 method. Tensile strength of 10 kg / mm ² or more and tensile elongation of 30% or more are mechanical properties that do not hinder the processing of the release film.

(7) Mouth index The discharge amount of the polymer is kept constant, and the flow rate (flow velocity, lip width of unit length) of the discharge polymer at 10 points in the width direction of the T die (1/2 width from the center to the end). , Calculated from the polymer density), and take the ratio of the flow rate at each position to the average value of the flow rate,
The average value was used as the mouthpiece index. Here, the polymer discharge rate was 330 kg / hr, the lip gap was 2 mm, and the lip length was 900 mm. Furthermore, the polymer density is 1.35 g.
/ Cc was used.

[0043]

EXAMPLES Next, the present invention will be described in detail with reference to examples.

Example 1 (1) Polymerization of PPS used in the present invention In an autoclave, 32.6 kg (25
0 mol, containing 40% by weight of water of crystallization, 100 g of sodium hydroxide, 36.1 kg (250 mol) of sodium benzoate, and N-methyl-2-pyrrolidone (hereinafter NMP).
It may be abbreviated as ").
After dehydration at the temperature of 1,4-dichlorobenzene 37.
5 kg (255 mol) and 20.0 kg of NMP were added and reacted at a temperature of 265 ° C. for 4 hours. The reaction product was washed with water and dried to obtain p-phenylene sulfide unit 10
21.1 kg (yield 78%) of 0 mol% poly-p-phenylene sulfide polymer was obtained. The obtained PP
The S polymer is PPS-1.

(2) Preparation of PPS Resin Composition PPS-1 obtained above was mixed with spherical silica fine powder having an average particle size of 0.7 μm and silica fine powder having an average particle size of 0.2 μm in a ratio of 2: 3. The mixture was mixed so that the total amount added was 0.3% by weight, and the mixture was supplied to a vent extruder having a twin screw with a diameter of 30 mm, melted at a temperature of 320 ° C., and a metal fiber was used. After passing through a filter with a% cut hole diameter of 10 μm, a gut-shaped resin composition was obtained by extrusion from a 3 mm hole diameter die. Further, the composition was cut into a length of about 5 mm to obtain pellets of the PPS resin composition.

(3) Production of PPS Biaxially Stretched Film The PPS pellets obtained in (2) above were heated under vacuum to a temperature of 1
It was dried at 80 ° C. for 3 hours. 40 mm of the dried pellets
It is supplied to an extruder having a single screw having a pore size, filtered through a filter with a 95% cut pore size using metal fibers and having a pore size of 8 μm, and passed through a mixer having a structure in which the molten polymer can be kneaded in a short tube. Was adjusted to 0.99 and extruded from a T-die having a linear lip with a length of 900 mm and a gap of 2 mm, and cast on a metal drum having a surface temperature of 24 ° C. The thickness of the obtained unstretched sheet is 1.2.
mm.

Subsequently, the sheet is sequentially introduced into a biaxial stretching machine, stretched 4.2 times in the longitudinal direction at a temperature of 98 ° C., passed through a tenter for further stretching in the width direction, and 3.6 at a temperature of 100 ° C. It was stretched twice. Furthermore, the same tenter was followed by heat treatment at a temperature of 260 ° C. for 10 seconds in a heat treatment chamber, followed by relaxation in the width direction under a 5% limited shrinkage. The thickness of the obtained film was 70 μm. The melt viscosity of the obtained film was 2900 poise. This film is referred to as release film-1. The average surface roughness (Ra) of the obtained film was 0.014 μm. In addition, when the film was polarized and confirmed, no streaky irregularities or other defects were found.

Examples 2 and 3, Comparative Examples 1 to 3 The amount of the inorganic particles used in Example 1 added to the PPS-1 polymer of Example 1 was 0.03% by weight, 0.1% by weight,
Five types of PPS resin compositions were prepared with 0.6% by weight, 1.0% by weight and 1.8% by weight. The mixing ratio of the two particles used was the same as in Example 1. The melt extrusion conditions, biaxial stretching, and heat treatment conditions are also the same as in Example 1. The obtained release films are referred to as release films-2 to 6 from the one having a small addition amount of inorganic particles.

Examples 4 and 5 PPS polymers were polymerized in the same manner as in Example 1 to obtain two types of polymers having different degrees of polymerization. A PPS resin composition was prepared from the polymer by the method of Example 1 to obtain a biaxially stretched film. The melt viscosity of the obtained film was 1100 poise and 5900 poise. Viscosity 1100
A release film-7 having a poise was used as a release film-7 and a release film-8 having a porosity of 5900 was used.

Example 6 (1) Polymerization of PPS Polymer A 50 L autoclave (made by SUS316) was charged with 56.26 mol of sodium hydrosulfide, 54.8 mol of sodium hydroxide, 16 mol of sodium acetate, and 170 mol of NMP. Next, dehydration was performed by raising the internal temperature to 220 ° C while stirring under a nitrogen gas stream. After dehydration,
After cooling the system to 170 ° C., 55 mol of paradichlorobenzene (p-DCB) and 0.055 mol of 1, 2, 4
-Trichlorobenzene (TCB) was added together with 2.5 L of NMP, and the system under a nitrogen stream was pressure sealed up to 2.0 kg / cm ² . 1 hour at 235 ° C, 5 at 270 ° C
After heating under stirring for an hour, the system is cooled to room temperature, the obtained slurry is put into 200 mol of water, and the polymer is separated after stirring at 70 ° C. for 30 minutes. Add this polymer to about 70 ℃
5 with stirring with ion-exchanged water (9 times polymer weight)
After washing twice, the mixture was stirred with a 5% aqueous solution of sodium acetate at about 70 ° C. under a nitrogen stream for about 1 hour. Further, it was washed with ion-exchanged water at about 70 ° C. three times, separated, and dried at 120 ° C. in a vacuum atmosphere for 20 hours to obtain a white powder PPS polymer. The polymer is PPS-2.

(2) Production of release film A biaxially stretched film was obtained by the method of Example 1 (release film-9).

Example 7 By the method of Example 6, p-DC which is a monomer composition of PPS was used.
Polymerization was carried out by adding 0.55 mol of TCB to 54.5 mol of B. The obtained PPS polymer is used as PPS
-3. Further, a biaxially stretched film was obtained under the conditions of Example 1 (release film-10).

Examples 8 to 10 PPS-1, PPS-2 and PPS-3 were used, without using the short pipe of the mixer structure between the filtration step and the T-die used in Example 1 Melt extrusion molding using a straight pipe,
Under the conditions of Example 1, three types of biaxially stretched films were obtained. The obtained films are called release films-11 to 13 in order from the one using PPS-1.

Comparative Examples 4 to 6 Using the PPS polymers of PPS-1 to 3 and the T die used in Example 1 having a die index of 0.93, melt extrusion molding was performed, and Example 8 was used. Under these conditions, three types of biaxially stretched films were obtained. The obtained films are used as release films 14 to 16 in order from the one using PPS-1.

Example 11 Using the manufacturing method of Example 8, PPS-1 was melt-molded using a T-die having a die index of 0.96 to obtain a biaxially stretched film. The obtained film was used as a release film-1.
7 is assumed.

The results of the examples and comparative examples of the present invention are shown in the table.

From Examples 1 to 3 and Comparative Examples 1 to 3, the average surface roughness (Ra) of the release films was 0.
It can be seen that if the thickness is not in the range of 005 to 0.03 μm, surface defects (defects other than streak defects) are given to the release film and the object of the present invention cannot be achieved. That is, the Ra is 0.00
If it is less than 5 μm, the film surface will be scratched due to friction with the film winding process or the conveying roll during processing, and if it exceeds 0.03 μm, the surface unevenness of the film will be large and will cause defects in the release film. The object of the invention cannot be achieved.

Further, it can be seen from Examples 1 and 4 to 7 that the melt viscosity of the raw material polymer is in the range of 1000 to 10000 poise in order to achieve the object of the present invention. When the viscosity is as low as 1000 poise, mechanical properties are deteriorated and the surface of the film is roughened by crystallization, which makes it difficult to achieve the object of the present invention. On the other hand, when the viscosity exceeds 10,000 poise, the most object of the present invention is the remarkable occurrence of streaky irregularities. Further, although Example 5 and Example 6 have almost the same melt viscosity, TCB is not used during the polymerization.
Next repeating unit

Embedded image It can be seen that the use of 100 mol% of polymer is advantageous in preventing streaky irregularities.

Further, comparing the characteristics of the release films of Examples 1, 6 and 7 with the release films of Examples 8-10, the polymer in the molten state was placed between the filtration step and the T-die. It is well understood that the use of a mixer having a structure capable of mixing makes it easier to achieve the object of the present invention.

Comparative Examples 4 to 6 have a T-die base index of 0.9.
3, and it is clearly understood that it is disadvantageous in reducing streaky irregularities as compared with the release films of Example 1 and Examples 6 and 7 in which the index is 0.99. Further, it can be seen from Example 11 that it is difficult to improve the stripe-shaped irregularity defect, which is the object of the present invention, unless the die index in the present invention is 0.95 or more.

[0061]

[Table 1]

[Table 2]

[0062]

EFFECTS OF THE INVENTION Since the present invention has the above constitution, the characteristics required for a release film, namely, heat resistance, chemical resistance,
It has been possible to provide a highly functional release film by which the surface defects of the streaky irregularities generated during melt molding, which has been a conventional problem of the polyphenylene sulfide film having excellent release properties and mechanical properties, can be improved.

The mold releasing polyphenylene sulfide film of the present invention is a mold releasing base material which is most suitable for applications such as liquid crystal films, ceramic films, high-performance polymer films, and the like which do not like fine surface defects.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29K 81:00 B29L 7:00

Claims (3)

[Claims] 1. The average surface roughness (Ra) is 0.005.
A polyphenylene sulfide film for release, which is a 0.03 μm film and has 12 / m or less streak-like irregularities of 0.3 μm or more generated on the film surface with respect to the base surface of the film. . 2. A polyphenylene sulfide resin composition comprising 9 units of repeating units of polyphenylene sulfide.
8 mol% or more is the following structural formula: Which has a melt viscosity of 300 ° C. and a shear rate of 200.
The polyphenylene sulfide film for mold release according to claim 1, which is in a range of 1,000 to 10,000 poise under sec ⁻¹ . 3. Melt-kneading with a melt extruder, filtration step, T
In a method for producing a biaxially oriented polyphenylene sulfide, in which a melt-formed sheet is extruded from a die, cast, biaxially stretched, and heat-treated, a mixer capable of melt-kneading is used at least between the filtration step and the T-die. The method for producing the release polyphenylene sulfide film according to claim 1 or 2.