JP2023096358A - polyphenylene sulfide film - Google Patents

Abstract

To provide a polyphenylene sulfide film which has small surface roughness on at least one surface and projections of more than 50 nm, and has a small difference (absolute value) between a maximum value and a minimum value of Young's modulus in an in-plane direction.SOLUTION: A polyphenylene sulfide film has a layer (hereinafter referred to as an A layer) which has central plane average roughness SRa on at least one surface of 150 nm or less, and the number SPc (50 nm) of projections of more than 50 nm from a central surface of the film of 5 pieces/0.2 mm2 or more, and has a difference (an absolute value) between a maximum value and a minimum value of Young's moduli in four directions of 0°, 45°, 90°, and 135°when a direction vertical to a longitudinal direction from an arbitrary point on the surface of the film is set at 0° of 0.5 GPa or less.SELECTED DRAWING: None

Description

The present invention relates to a polyphenylene sulfide film having small surface roughness on at least one surface, protrusions exceeding 50 nm, and a small difference (absolute value) between the maximum value and the minimum value of Young's modulus in the in-plane direction.

As electronic equipment and information equipment become more sophisticated and precise, the quality requirements for the materials used are becoming stricter. For example, high-frequency circuit board substrate films, release films, capacitor substrate films, and the like have strict quality requirements. These members often require complex processing, such as bonding other materials to the base film or cutting into small pieces.

Therefore, in order to prevent the properties of the final product from changing in the direction in which the film is cut, it is required that the in-plane physical property variation of the base film is small.

In addition, in the base film for high-frequency circuit boards, since electric signals flow on the circuit surface, the surface shape of the base film affects the transmission characteristics. That is, if the surface roughness of the substrate film is large or the number of protrusions is large, the transmission loss increases, so a film with small surface roughness is required.

Films and sheets conventionally used in the above fields are made of polyethylene, polypropylene, polyester, polyimide, fluororesin, etc. Among them, polyphenylene sulfide film has heat resistance, chemical resistance, and dimensional stability. , the mechanical properties are good, so it can be preferably used, and the range of use is expanded. Among them, as an example of providing a polyphenylene sulfide film with a small surface roughness, a polyphenylene sulfide film containing substantially no particles has been proposed (Patent Document 1).

WO2007/129695

The surface roughness of the polyphenylene sulfide film is adjusted by using inorganic particles or dispersing thermoplastic resin, but it is difficult to achieve both a small surface roughness and a small amount of high protrusions. Met.

The present invention relates to the provision of a polyphenylene sulfide film having small surface roughness on at least one surface, protrusions exceeding 50 nm, and a small difference (absolute value) between the maximum value and the minimum value of Young's modulus in the in-plane direction.

In order to solve the above problems, the present invention has the following configurations. i.e.
[1] At least one surface has a center plane average roughness SRa of 150 nm or less, and a surface having a number of protrusions exceeding 50 nm from the center plane of the film SPc (50 nm) of 5/0.2 mm ² or more ( The surface is referred to as the A surface) (the layer is referred to as the A layer), and the direction perpendicular to the longitudinal direction is 0° from an arbitrary point on the surface of the film, 0° to 45°, 90° A polyphenylene sulfide film having a difference (absolute value) of 0.5 GPa or less between the maximum value and the minimum value of Young's modulus in the four directions when the Young's modulus is measured in the directions of 135° and 135°.
[2] The polyphenylene sulfide film according to [1], wherein the surface A has a ten-point average roughness SRz of 1300 nm or less.
[3] The polyphenylene sulfide film according to [1] or [2], wherein the layer A is substantially free of particles.
[4] The A layer contains a polyphenylene sulfide resin (A) as a main component, and contains a thermoplastic resin (B) different from the resin (A), and the thermoplastic resin (B) has an average dispersed diameter of 0.000. The polyphenylene sulfide film according to any one of [1] to [3], which is 5 μm or more and 1.2 μm or less.
[5] The polyphenylene sulfide film according to [4], wherein the thermoplastic resin (B) contains any one of the following chemical formulas.

(where R ₁ to R ₆ in the formula are each H, OH group, methoxy group, ethoxy group, trifluoromethyl group, aliphatic group having 1 to 13 carbon atoms, or aromatic group having 6 to 10 carbon atoms). or.)
[6] The polyphenylene sulfide film of [4] or [5], wherein the thermoplastic resin (B) has a sulfonyl group.
[7] When the total content of the resin (A) and the thermoplastic resin (B) in the layer A is 100 parts by mass, the content of the thermoplastic resin (B) is 0.1 parts by mass or more50 The polyphenylene sulfide film according to any one of [4] to [6], which is part by mass or less.
[8] With the direction perpendicular to the longitudinal direction from an arbitrary point on the surface of the polyphenylene sulfide film as 0°, the dimensional change rate in 0° and 90° directions at 250 ° C. × 10 minutes is 5.0% or less. A polyphenylene sulfide film according to any one of [1] to [7].
[9] The polyphenylene sulfide film according to any one of [1] to [8], wherein the polyphenylene sulfide film has a thickness of 10 μm or more and 500 μm or less.

According to the present invention, there is provided a polyphenylene sulfide film having small surface roughness on at least one surface, protrusions exceeding 50 nm, and a small difference (absolute value) between the maximum value and the minimum value of Young's modulus in the in-plane direction. can do.

Polyphenylene sulfide in the present invention refers to a polymer in which 85 mol % or more (preferably 90 mol % or more) of repeating units are composed of structural units represented by the following structural formulas. If such a component is less than 85 mol %, the crystallinity, softening point, etc. of the polymer may be lowered, and heat resistance, dimensional stability, mechanical properties, releasability, etc. may be impaired.

In the above polyphenylene sulfide, a unit containing a copolymerizable sulfide bond may be included as a repeating unit as long as it is less than 15 mol %, preferably less than 10 mol % of the repeating unit. The method of copolymerization of the polymer may be random or block type.

The polyphenylene sulfide film of the present invention preferably has a layer (the layer is referred to as the A layer) having a surface (the surface is referred to as the A surface) in which at least one surface has a center plane average roughness SRa of 150 nm or less. The center plane average roughness SRa of the A plane is preferably 130 nm or less, more preferably 100 nm or less. If the center plane average roughness SRa of the A plane is larger than 150 nm, for example, when the film is used as a substrate for a high frequency circuit board, the transmission loss of the circuit may deteriorate, that is, the transmission characteristics may be impaired. In addition, when an adhesive or release agent is applied, uneven application or omission of application may occur, which may impair the quality of the product. In order to minimize coating unevenness and coating omission, the central surface average roughness SRa is preferably 100 nm or less.

In the polyphenylene sulfide film of the present invention, it is preferable that the SPc (50 nm) of the surface A is 5/0.2 mm ² or more. SPc (50 nm) is the number of protrusions exceeding 50 nm from the center plane of the film. The SPc (50 nm) of the A side is more preferably 10/0.2 mm ² or more, and still more preferably 20/0.2 mm ² or more. When the SPc (50 nm) of the A side is 5 pieces/0.2 mm ² or more, the static friction coefficient is lowered, so that the transportability of the film is improved, which is preferable. If the SPc (50 nm) of the A side is less than 5 particles/0.2 mm ² , the slippage of the film is deteriorated and problems such as blocking may occur. In the polyphenylene sulfide film of the present invention, the number of protrusions SPc (5 nm) exceeding 5 nm from the center plane of the A-side film is preferably 1000/0.2 mm ² or less. If the SPc (5 nm) of the A side is larger than 1000/0.2 mm ² , when the film is used as a substrate for a high-frequency circuit board or the like, the transmission loss of the circuit may deteriorate, that is, the transmission characteristics may be impaired. The method for making the center surface average roughness SRa of the A side equal to or less than a certain value while making the SPc equal to or more than a certain value is not particularly limited. It can be achieved by controlling the rotation speed and adjusting the dispersion diameter of the thermoplastic resin (B).

SRa, SPc (50 nm), and SPc (5 nm) are determined by the method described in Examples.

In the polyphenylene sulfide film of the present invention, the direction perpendicular to the longitudinal direction is 0 ° from an arbitrary point on the film surface, and the Young's modulus is measured from 0 ° to 45 °, 90 °, and 135 °. The difference (absolute value) between the maximum value and the minimum value of Young's modulus is preferably 0.5 GPa or less. When the difference (absolute value) between the maximum value and the minimum value of Young's modulus in the four directions is 0.5 GPa or less, the film can be suitably used as a material without variation in properties depending on the cutting direction of the film. can. The difference (absolute value) between the maximum value and the minimum value of Young's modulus in the four directions is obtained by the method described in the examples.

The polyphenylene sulfide film of the present invention preferably has a ten-point average roughness SRz of the A side of 1300 nm or less, more preferably 1000 nm or less. If the surface A has a ten-point average roughness SRz of more than 1300 nm, when the film is used as a substrate for a high-frequency circuit board or the like, the transmission loss of the circuit may deteriorate, that is, the transmission characteristics may be impaired. In addition, when an adhesive or release agent is applied, uneven application or omission of application may occur, which may impair the quality of the product. In order to minimize coating unevenness and coating omission, the ten-point average roughness SRz is preferably 800 nm or less.

In the polyphenylene sulfide film of the present invention, the layer A preferably contains substantially no particles. When the layer A contains particles, for example, when the particles are inorganic particles, the particles aggregate to form coarse protrusions or defects, which may impair the quality of the film.

In the polyphenylene sulfide film of the present invention, the A layer contains a polyphenylene sulfide resin (A) as a main component, contains a thermoplastic resin (B) different from the resin (A), and has an average dispersion of the thermoplastic resin (B) The diameter is preferably 0.5 μm or more and 1.2 μm or less. When the average dispersed diameter of the thermoplastic resin (B) is less than 0.5 μm, the thermoplastic resin (B) is finely dispersed, and it may be difficult to achieve the SPc of the present application. When the average dispersed diameter of the thermoplastic resin (B) is larger than 1.2 μm, the thermoplastic resin (B) is insufficiently dispersed, and it may be difficult to achieve the SRa of the present application. In addition, the said average dispersion diameter shall be calculated|required by the method as described in an Example.

In the polyphenylene sulfide film of the present invention, the thermoplastic resin (B) preferably contains any one of the following chemical formulas. When the thermoplastic resin (B) does not contain any of the chemical formulas below, peeling may occur at the interface between the polyphenylene sulfide and the thermoplastic resin (B), resulting in a decrease in film strength.

(where R ₁ to R ₆ in the formula are each H, OH group, methoxy group, ethoxy group, trifluoromethyl group, aliphatic group having 1 to 13 carbon atoms, or aromatic group having 6 to 10 carbon atoms). or.)
In the polyphenylene sulfide film of the present invention, the thermoplastic resin (B) preferably has a sulfonyl group. When the thermoplastic resin (B) has a sulfonyl group, the film formability of the polyphenylene sulfide film is improved, and the dimensional change rate after heating can be reduced. Thermoplastic resins having a sulfonyl group include polyethersulfone, polyphenylsulfone, and polysulfone. Among them, polyphenylsulfone is preferably used from the viewpoint of heat resistance and chemical resistance. Polyphenylsulfone is a resin having a low dielectric constant, and is preferable in that the transmission characteristics are not deteriorated when the polyphenylene sulfide film of the present invention is used as a substrate for a circuit board.

In the polyphenylene sulfide film of the present invention, the content of the thermoplastic resin (B) is 0.00 parts when the total content of the resin (A) and the thermoplastic resin (B) in the layer A is 100 parts by mass. It is preferably from 1 part by mass to 50 parts by mass, more preferably from 0.5 part by mass to 30 parts by mass. When the content of the thermoplastic resin (B) is less than 0.1 part by mass, not only is the film formability of the polyphenylene sulfide film deteriorated, but it may also be difficult to achieve the desired surface roughness. If the content of the thermoplastic resin (B) is more than 50 parts by mass, it may be difficult to achieve the desired surface roughness.

The polyphenylene sulfide film of the present invention has a dimensional change rate of 5.0% or less at 250 ° C. × 10 minutes in the 0 ° and 90 ° directions, with the direction perpendicular to the longitudinal direction from an arbitrary point on the film surface as 0 °. is preferably If the dimensional change rate at 250° C.×10 minutes is more than 5.0%, the film shrinks significantly during processing performed at high temperatures such as soldering, and may not be suitable for use as a base material. In addition, the said dimensional change rate shall be calculated|required by the method as described in an Example.

The polyphenylene sulfide film of the present invention preferably has a thickness of 10 µm or more and 500 µm or less, more preferably 250 µm or less. By setting the thickness of the film to the above-mentioned lower limit or more, the stiffness of the film is improved, and the film can be suitably used as a base material. By making the film thickness equal to or less than the above-mentioned upper limit, the occurrence of burrs during processing of the film is suppressed, and handling becomes easy.

The polyphenylene sulfide film of the present invention contains additives such as antioxidants, heat stabilizers, lubricants, and ultraviolet absorbers as long as they do not adversely affect the surface roughness, SPc, and Young's modulus of the film of the present invention. may be added.

A preferred embodiment of the present invention is a polyphenylene sulfide film roll obtained by winding a polyphenylene sulfide film. The polyphenylene sulfide film roll of the present invention preferably has a film width of 500 mm or more. An intermediate product roll obtained by winding the film immediately after production may be used, or a product roll obtained by slitting an intermediate product roll may be used.

The polyphenylene sulfide film of the present invention may be a single film or a composite film. Composite films include laminated films of two or more layers. For example, the polyphenylene sulfide film of the present invention may be a two-layer laminated film consisting of A layer/B layer or a three-layer laminated film consisting of A layer/B layer/A layer having the polyphenylene sulfide film of the present invention as a surface layer (A layer). When used for release applications or high-frequency circuit board applications, it is preferable to apply the polyphenylene sulfide film of the present invention to all layers from the viewpoint of flatness and voltage resistance.

On the surface of the polyphenylene sulfide film of the present invention, a resin or compound such as an antistatic agent is applied or laminated as long as it does not adversely affect the surface roughness, SPc, and Young's modulus of the film of the present invention. Appropriate surface treatment such as corona discharge treatment or plasma treatment may be applied.

(Film manufacturing method)
Regarding the method for producing the polyphenylene sulfide film of the present invention, it is preferable to produce it, for example, by the steps shown below.

First, the method for producing the polyphenylene sulfide of the present invention will be described. Polyphenylene sulfide can be produced, for example, by polymerizing an alkali metal sulfide (alkali sulfide) and a dihalobenzene.

Alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, and cesium sulfide, among which sodium sulfide is preferred. These alkali metal sulfides can be used as hydrates or aqueous mixtures, or in anhydrous form. In addition, alkali metal sulfide prepared in situ in the reaction system, sulfide, lithium hydroxide, alkali metal sulfide prepared from alkali metal hydrate such as sodium hydroxide and hydrogen sulfide can also be used. can. Alkali metal sulfides may be used alone or in combination of two or more.

Dihalobenzenes include p-dihalobenzenes such as p-dichlorobenzene and p-dibromobenzene, m-dihalobenzenes such as m-dichlorobenzene, and halogen atoms such as 1-methoxy-2,5-dihalobenzene and 3,5-dichlorobenzoic acid. dihalobenzene containing substituents other than Among these, p-dihalobenzene is preferred, and p-dichlorobenzene is particularly preferred. Dihalobenzene may be used alone or in combination of two or more.

The amount of dihalobenzene used (amount charged) is preferably in the range of 0.9 to 2.0 mol, more preferably 1.0 to 1.3 mol, per 1 mol of alkali metal sulfide charged. of polyphenylene sulfide. By setting this use ratio within the above range, it becomes easy to obtain polyphenylene sulfide with high viscosity (high degree of polymerization) suitable for processing.

In the present invention, a monohalo compound (not necessarily an aromatic compound) can be used in combination with dihalobenzene in order to form the terminal of the polyphenylene sulfide produced or to adjust the polymerization reaction or molecular weight. In addition, in order to form a branched or crosslinked polymer, trihalo or higher polyhalo compounds (not necessarily aromatic compounds) such as 1,2,4-trichlorobenzene and 1,3,5-trichlorobenzene, active hydrogen It is also possible to use a contained halogen aromatic compound, a halogen aromatic nitro compound, etc. in combination.

In the present invention, in order to adjust the degree of polymerization, it is preferable to add a polymerization aid for the reaction. As the polymerization aid, a known polymerization aid generally used as a polymerization aid for polyphenylene sulfide can be used. Examples include alkali metal hydroxide (caustic alkali), alkali metal carboxylate, alkali metal carbonate, alkaline earth metal hydroxides, alkaline earth metal carbonates and the like. Among these, alkali metal hydroxides and alkali metal carboxylates are preferably used.

Alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. Alkali metal salts of carboxylic acids include, for example, lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate and potassium p-toluate. Sodium acetate is preferably used due to its ready availability. Alkali metal salts of carboxylic acids can be used as anhydrides, hydrates or aqueous solutions. Further, the alkali metal salt of carboxylic acid is obtained by combining an organic acid and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates and alkali metal bicarbonates in an organic amide solvent. It may be formed by adding equistoichiometric equivalents and reacting them.

One of the polymerization aids may be used alone, or two or more of them may be used in combination. The amount of the polymerization aid used can be appropriately selected from a wide range depending on the type of the polymerization aid itself and the types of the alkali metal sulfide and dihalobenzene. A range of 0.01 mol to 5 mol is preferred, and a range of 0.1 to 2 mol is more preferred.

As the solvent, it is preferable to use a polar solvent such as an organic amide solvent. Among organic amide solvents, N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone; caprolactams such as N-methyl-ε-caprolactam; ,3-dialkyl-2-imidazolidinone, tetraalkylurea, hexaalkylphosphoric acid triamide, and other abrotic organic amide solvents and other amide-based high-boiling polar solvents are preferably used. Among these, N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) is particularly preferably used. The amount of solvent used is preferably in the range of 0.2 to 10 mol, more preferably in the range of 2 to 5 mol, per 1 mol of the alkali metal sulfide charged.

(1) The polyphenylene sulfide used in the polyphenylene sulfide film of the present invention contains an appropriate amount of an alkali metal sulfide and dihalobenzene, and if necessary, an appropriate amount of a halogenated compound other than dihalobenzene and a polymerization aid. It can be produced by adding to a polar solvent of and reacting at high temperature and high pressure. The pressure in the polymerization system is appropriately selected according to the type and amount of auxiliary agent used, the desired degree of polymerization, and the like. The temperature and polymerization time in the polymerization system are also appropriately selected according to the type and amount of the auxiliary agent to be used, the desired degree of polymerization, etc., but preferably at a temperature of 200 to 300° C. for 20 minutes to 50 hours, or more. It is preferably 1 to 10 hours at a temperature of 230 to 280°C. Powdery or granular polyphenylene sulfide is obtained as described above. Next, the obtained powdery or granular polyphenylene sulfide is washed with water and/or a solvent to separate by-salts, polymerization aids, unreacted monomers, and the like.

(2) As described above, when adding a thermoplastic resin (B) other than polyphenylene sulfide to the polyphenylene sulfide film of the present invention, first, the thermoplastic resin (B) is added to the powder obtained in (1) above. Alternatively, mix with granular polyphenylene sulfide and mix uniformly with a Henschel or the like. When additives such as antioxidants, heat stabilizers, lubricants, and ultraviolet absorbers are added, they are mixed with the polyphenylene sulfide in the same manner.

Next, the obtained mixture is supplied to an extruder (preferably an extruder having one or more stages of vent holes), melt-kneaded at a temperature of 290 to 360 ° C. and extruded from a suitable die to obtain a polyphenylene sulfide resin composition. get Alternatively, the polyphenylene sulfide resin composition may be formed into pellets by melt-molding into a gut shape and cutting into lengths of about 2 to 10 mm. The obtained polyphenylene sulfide resin composition is dried in a vacuum heating dryer at a temperature of 100 to 180° C. for 1 to 5 hours.

In addition, when the thermoplastic resin (B) is not added, the polyphenylene sulfide obtained in (1) is mixed with additives such as antioxidants, heat stabilizers, lubricants, and ultraviolet absorbers as necessary, It can be extruded or melt-molded in the same manner as the mixture containing the thermoplastic resin (B) and used as a polyphenylene sulfide resin composition.

The polyphenylene sulfide resin composition thus produced may be used singly or in combination of two or more. For example, polyphenylene sulfide resin pellets to which the thermoplastic resin (B) is added (hereinafter also referred to as master pellets) and polyphenylene sulfide resin pellets to which the thermoplastic resin (B) is not added (hereinafter also referred to as base pellets) can be mixed and used.

(3) Next, the polyphenylene sulfide resin pellets obtained in (2) are used to produce the polyphenylene sulfide film of the present invention. The polyphenylene resin pellets obtained in (2) are stirred with a mixer while being heated to a temperature of 120 to 230° C. (preferably 160 to 200° C.) under reduced pressure (preferably with a degree of vacuum of 0 to 50 mmHg), and stirred for 3 hours. Dry above (preferably for 5 to 10 hours). The drying of the polyphenylene sulfide resin composition may be carried out in multiple stages, such as drying the polyphenylene sulfide resin composition as described above, slowly cooling it to room temperature, and drying it again. Here, if the drying temperature exceeds 230°C, there is a concern that the dried raw material will solidify and hinder the film formation. High-boiling compounds that volatilize on heating can remain and cause film defects. If the pressure reduction is insufficient, the polyphenylene sulfide resins are crosslinked with each other by oxygen, and a modified polymer is likely to be produced.

The dried polyphenylene sulfide resin composition is then used to form the polyphenylene sulfide film of the present invention, which may be a single layer or multiple layers. When a composite film is produced, a lamination method such as coating, lamination or co-extrusion can be used. Among them, lamination by co-extrusion is preferable from the viewpoint of thickness control of each layer constituting the polyphenylene sulfide film of the present invention.

The polyphenylene sulfide film of the present invention is produced as follows. First, a polyphenylene sulfide resin composition is supplied to a melt extruder and heated to a temperature higher than the melting point of the polyphenylene sulfide resin composition (preferably 290 to 360° C.) to melt. Next, the melt is extruded from a slit-shaped mouthpiece outlet and rapidly cooled by a method such as cooling and solidification (casting) on a rotating metal drum called a casting roll to produce an unstretched film. At this time, it is preferable to install a gear pump, a static mixer, or a filtration device in the polymer flow path.

The obtained unstretched film is subjected to a sequential biaxial stretching method in which the film longitudinal direction (longitudinal direction) and film width direction (horizontal direction) are successively stretched using a roll group and a tenter. Simultaneous biaxial stretching, in which stretching is carried out at the same time, is exemplified, and among these, sequential biaxial stretching is preferred.

The stretching conditions when the sequential biaxial stretching method is used are appropriately selected from a wide range according to various conditions such as the type of polyphenylene sulfide contained in the polyphenylene sulfide resin composition and the presence or absence and type of other resins and additives. However, at a temperature of 60 to 150 ° C., preferably 70 to 130 ° C., more preferably 80 to 110 ° C., the longitudinal direction (longitudinal direction) and the width direction (horizontal direction) are each 2 to 7 times, preferably 2 It is preferable to draw at a magnification of up to 5 times, more preferably 3 to 5 times.

It is preferable to further heat-treat the obtained stretched film. The heat treatment conditions at this time can be appropriately selected from a wide range according to various conditions such as the type of polyphenylene sulfide contained in the polyphenylene sulfide resin composition and the presence or absence and type of other resins and additives. 180 to (melting point of polyphenylene sulfide composition) ° C., preferably 200 to (melting point of polyphenylene sulfide resin composition -5) ° C., fixed length or limited shrinkage of 15% or less for 1 to 60 seconds. , heat resistance, mechanical properties, and thermal dimensional stability. In addition, the film may be relaxed in one or two directions to improve its thermal dimensional stability. In particular, if the film is relaxed by 5.5% or more in the width direction, the dimensional change rate can be easily reduced, which is preferable. It is more preferable to relax 6.5% or more and 15% or less in the width direction of the film. Since it has both properties, it can be particularly suitably used for capacitor applications and mold release applications.

(Method for measuring physical properties)
(1) Center surface average roughness SRa, ten-point average roughness SRz
The surface of the film was measured by a stylus method under the following conditions using a three-dimensional surface roughness meter ET4000AK (manufactured by Kosaka Laboratory Ltd.). The center plane average roughness SRa (unit: nm) is the average of the absolute values of the difference between the height of the roughness curved surface and the height of the center plane of the roughness curved surface. The ten-point average roughness SRz (unit: nm) is the difference between the height of the roughness curved surface and the height of the central surface of the roughness curved surface, and It represents the average value of the absolute values of a total of 10 points for the depth of the valley bottom up to the th.
Needle pressure 100μN
Measurement length 500μm
Longitudinal magnification 20000 times CUT OFF 250 μm
Measurement speed 100 μm/s
Measurement interval 5 μm
80 records.

(2) SPc (50 nm), SPc (5 nm)
The surface of the film was measured by a stylus method under the following conditions using a three-dimensional surface roughness meter ET4000AK (manufactured by Kosaka Laboratory Ltd.). In addition, SPc (50 nm) is the number of surface protrusions with a protrusion height exceeding 50 nm per 0.2 mm ² of the film surface, and SPc (5 nm) is 5 nm per 0.2 mm ² of the film surface. It counts the number of surface protrusions with a protrusion height exceeding the above.
Needle pressure 100μN
Measurement length 500μm
Longitudinal magnification 20000 times CUT OFF 250 μm
Measurement speed 100 μm/s
Measurement interval 5 μm
80 records.

(3) Young's modulus Based on JIS-C2151 (2019), the film is cut into strips with a width of 10 mm, the marked line distance is 100 mm, and the test speed is 200 mm / min using a tensile tester. Young's modulus was calculated.
Y1 = tension at 0.8% elongation - tension at 0.7% elongation Y2 = tension at 0.9% elongation - tension at 0.8% elongation Y3 = 1.0% elongation Tension at time−Tension Young's modulus at elongation 0.9%=(Y1+Y2+Y3)/3/width/thickness.

(4) Average Dispersion Diameter Using a microtome, a sample was prepared by cutting a cross-section of the film in a direction perpendicular to the longitudinal direction. The cut surface was observed using a field emission scanning electron microscope JSM-6700F (manufactured by JEOL Ltd.), and an image was obtained at a magnification of 5000 to confirm the dispersed shape of the thermoplastic resin (B). 20 arbitrary thermoplastic resin (B) dispersed phases were selected, the circumscribed circle of each dispersed phase was taken, and the average value of the diameters was taken as the average dispersed diameter.

(5) Dimensional change rate (%) at 250°C x 10 minutes
Based on JIS-C2151 (2019), cut the film into strips with a width of 10 mm so that the longitudinal direction and the direction perpendicular to the longitudinal direction are the measurement directions, and mark the initial length of 200 mm. The film was heat-treated in an oven at 250° C. for 10 minutes, and the dimensional change rate was calculated from the length of the film after heating as follows.

Initial length 200 mm: A, film length after heating: B
Dimensional change rate (%)=(AB)/A×100.

(6) Thickness (μm)
A slice piece of the film cross-sectionally cut using a microtome was observed with a transmitted light microscope, and the thickness (μm) was measured.

(7) Static Friction Coefficient of Film Films were superimposed on the front and back, and the static friction coefficient was measured under the following conditions using a slip tester ST-200 (manufactured by Technonies Co., Ltd.).
load 200g
Measurement length 5mm
Measurement speed 150mm/min
Measurement temperature 23±3℃
Measurement humidity 65±10%RH
It was evaluated as follows from the static friction coefficient measurement value.
O: Coefficient of static friction is 1.3 or less x: Coefficient of static friction exceeds 1.3.

(8) Evaluation of missing coating material After coating the surface of the film with a coating material for providing an adhesive layer, missing coating material was evaluated as follows.
◎: When the missing coating is 1 place/m ² or less ○: When the missing coating is 5 places/m ² or less and more than 1 place/m ^{2 △: When the missing coating is 10 places/m 2 or} less and 5 places/m ² When more ×: When there are more than 10 coating omissions / m ² <Composition of coating material>
Carnauba wax (Carnauba No. 1, manufactured by Toyo Adolé Co., Ltd.): 30 parts by mass Paraffin wax (HNP-10, manufactured by Nippon Seiro Co., Ltd.): 35 parts by mass Ethylene-vinyl acetate copolymer (MB-11, manufactured by Sumitomo Chemical Co., Ltd.): 10 parts by mass <Application method>
Using a hot-melt coater, the film was coated at 130° C. in an amount of 1 m 2 on one side of the film so that the thickness of the coating layer after drying would be ¹ μm.

(9) Curl evaluation Using a vacuum deposition device (VPC-260F) manufactured by ULVAC KIKO Co., Ltd. on the surface of the film, aluminum deposition was performed with a film thickness of 50 nm, and then the film had an outer diameter of 100 mm and an inner diameter of 90 mm. When punched into a mold and placed with the aluminum vapor-deposited surface facing up, warpage in the direction of 0° to 45°, 90°, and 135° from an arbitrary point on the surface of the film, with the direction perpendicular to the longitudinal direction as 0° The difference (absolute value) between the maximum height and the minimum height was measured and the curl was evaluated as follows.
◯: When the difference (absolute value) between the maximum height and the minimum height of warpage is 20 mm or less ×: When the difference (absolute value) between the maximum height and the minimum height of warp is greater than 20 mm.

[Film production]
(Reference Example 1) Method for producing polyphenylene sulfide powder.

A 70 L autoclave equipped with a stirrer was charged with 8.181 kg (70.00 mol) of a 48% by weight aqueous sodium hydrosulfide solution, 2.943 kg (70.63 mol) of sodium hydroxide with a purity of 96%, N-methyl-2-pyrrolidone. 11.45 kg (115.5 mol) of (NMP), 2.239 kg (27.30 mol) of anhydrous sodium acetate, and 4.900 kg (272.2 mol) of ion-exchanged water were charged, and heated to 240°C under normal pressure while passing nitrogen. After 9.12 kg of water and 0.14 kg of NMP were distilled off, the reactor was cooled to 160°C. The stirring speed in this reaction was 240 revolutions per minute (240 rpm).

The amount of water remaining in the system per 1 mol of the charged alkali metal sulfide was 72.0 mol including the water consumed for the hydrolysis of NMP. In addition, 0.020 mol of hydrogen sulfide per 1 mol of charged alkali metal sulfide was scattered outside the reaction system.

Next, 10.29 kg (69.97 mol) of p-dichlorobenzene (p-DCB) and 9.090 kg (91.70 mol) of NMP were added to the reaction system. After sealing the reaction vessel under nitrogen gas, the temperature was increased from 200°C to 227°C at a rate of 0.8°C/min while stirring at 400 rpm, and then from 227°C to 270°C at a rate of 0.6°C/min. The temperature was raised at a high speed and held at 270° C. for 140 minutes. After that, the reaction system was gradually cooled to 250° C. while adding 2.346 kg (130.3 mol) of ion-exchanged water to the system over 15 minutes. Then, the reaction system was gradually cooled from 250° C. to 200° C. at a rate of 1.0° C./min, and then rapidly cooled to near room temperature.

The resulting polymer was washed with 15 kg of N-methyl-2-pyrrolidone solvent (bath ratio: 15) per 1 kg of dry PPS at 90° C. for 1.5 hours and filtered. The resulting cake was washed twice with ion-exchanged water (bath ratio 15) at 70°C for 1.5 hours and filtered. C. for 1.5 hours, washing/filtration was performed again, and washing/filtration was again performed twice at 70.degree. The obtained polymer was dried at a temperature of 150° C. under vacuum for 4 days to obtain a polyphenylene sulfide powder.

(Reference Example 2) Preparation of thermoplastic resin (B) master pellets.

80 parts by mass of the polyphenylene sulfide powder polymer prepared in Reference Example 1 and 20 parts by mass of polyphenylsulfone (PPSU: Solvay Specialty Polymers Co., Ltd., "Radel R-5000LC") as the thermoplastic resin (B) were added in the same direction. It was supplied to a vented extruder with a rotating type twin screw and melted at a temperature of 320°C. This melt was extruded into a gut shape and cut into lengths of about 3 mm to obtain master pellets having a PPSU content of 20% by mass. Hereinafter, it is referred to as PPS resin B.

(Reference Example 3) Production of base pellets.

Only the above polyphenylene sulfide powder polymer was melt extruded in the same manner as in Reference Example 2 to obtain base pellets of polyphenylene sulfide resin. Hereinafter, it is referred to as PPS resin A.

(Example 1)
After mixing the PPS resin A and the PPS resin B obtained as described above so that the content of PPSU is 5% by mass with respect to the total amount of the resins, the mixture is dried under a reduced pressure of 3 mmHg using a rotary vacuum dryer. and dried at a temperature of 180° C. for 4 hours.

The dried pellets were supplied to a single-screw extruder with L/D=29 and Φ90 mm, melted at 310° C. at a screw rotation speed of 90 rpm, and extruded from a T-die mouthpiece in the form of a sheet. Next, this sheet was wound around a casting drum having a surface temperature of 25° C. by an electrostatic casting method, and cooled and solidified to produce an unstretched film.

Using a sequential biaxial stretching method, the obtained unstretched film is stretched 3.2 times in the longitudinal direction at a temperature of 100 ° C., and further stretched in the width direction through a tenter to stretch 3.6 times in the width direction at a temperature of 100 ° C. Double stretched. Further, in a heat treatment chamber following the tenter used for stretching in the width direction, heat treatment is performed at a temperature of 280 ° C., relaxation treatment is performed in the width direction under a limited shrinkage of 6.8%, and the film is wound around a core. A film roll was obtained by winding a polyphenylene sulfide film of 680 mm in the width direction by dividing the film in the width direction with a slit. The evaluation results are shown in the table. In addition, in the evaluation of the film surface, the evaluation results of the surface not in contact with the casting drum are shown in the table.

(Example 2)
A roll was obtained by winding a polyphenylene sulfide film in the same manner as in Example 1, except that the heat setting temperature was set as shown in Table 1.

(Example 3)
A roll of polyphenylene sulfide film was obtained in the same manner as in Example 1, except that the film thickness, extruder screw rotation speed, longitudinal draw ratio, and transverse draw ratio were as shown in Table 1.

(Example 4)
A roll obtained by winding a polyphenylene sulfide film in the same manner as in Example 1, except that the film thickness, extruder screw rotation speed, longitudinal draw ratio, transverse draw ratio, and heat setting temperature were as described in Table 1. got

(Example 5)
A roll was obtained by winding a polyphenylene sulfide film in the same manner as in Example 1, except that the extruder screw rotation speed was set as shown in Table 1.

(Example 6)
A roll of polyphenylene sulfide film was obtained in the same manner as in Example 1, except that the film thickness, extruder screw rotation speed, longitudinal draw ratio, and transverse draw ratio were as shown in Table 1.

(Example 7)
The film roll obtained in Example 1 was annealed for 1 minute while being conveyed under a tension of 20 N in an oven heated to 210° C., and then wound up to obtain a film roll.

(Example 8)
The film roll obtained in Example 3 was annealed for 1 minute while being conveyed under a tension of 20 N in an oven heated to 210° C., and then wound up to obtain a film roll.

(Comparative example 1)
A roll was obtained by winding a polyphenylene sulfide film in the same manner as in Example 1, except that the extruder screw rotation speed, longitudinal draw ratio, and relaxation rate were set as shown in Table 1.

(Comparative example 2)
Polyamide (PA) was used as the thermoplastic resin (B), and the film thickness, extruder screw rotation speed, longitudinal draw ratio, transverse draw ratio, heat setting temperature, and relaxation rate were as described in Table 1. A roll of polyphenylene sulfide film was obtained in the same manner as in Example 1.

(Comparative Example 3)
Polyphenylene ether (PPE) was used as the thermoplastic resin (B), and the film thickness, extruder screw rotation speed, longitudinal draw ratio, transverse draw ratio, heat setting temperature, and relaxation rate were as described in Table 1. A roll was obtained by winding a polyphenylene sulfide film in the same manner as in Example 1.

(Observation summary)
In Examples 1 to 8, by containing PPSU, melting at an appropriate extruder screw rotation speed, and forming a film at an appropriate longitudinal draw ratio, the surface roughness is small, so that the coating material does not come off. Since there are few protrusions exceeding 50 nm, the coefficient of friction is small and the film transportability is good, and the difference (absolute value) between the maximum value and the minimum value of Young's modulus in the in-plane direction is small, so the in-plane after punching A high-quality polyphenylene sulfide film roll was obtained in which variation in warpage in the direction was suppressed.

In Comparative Example 1, the average dispersion diameter of the thermoplastic resin (B) is large due to the low extruder screw rotation speed, the surface roughness is large, and the longitudinal draw ratio is small. A polyphenylene sulfide film roll with a large difference (absolute value) between the value and the minimum value was obtained. The polyphenylene sulfide film roll obtained in this comparative example is suitable for high-quality applications such as high-frequency circuit boards, because there are many missing coating materials and large variations in warpage in the in-plane direction after punching. may not be used for

In Comparative Example 2, PA was used as the thermoplastic resin (B), and the average dispersion diameter of the thermoplastic resin (B) was small due to the high extruder screw rotation speed, and a polyphenylene sulfide film roll without projections exceeding 50 nm was obtained. was taken. The polyphenylene sulfide film roll obtained in this comparative example is difficult to handle due to its high coefficient of friction, and may not be suitable for high-quality applications such as high-frequency circuit boards.

In Comparative Example 3, PPE was used as the thermoplastic resin (B), and since the extruder screw rotation speed was low, the average dispersion diameter of the thermoplastic resin (B) was small, the surface roughness was large, and the longitudinal draw ratio was A polyphenylene sulfide film roll having a large difference (absolute value) between the maximum value and the minimum value of Young's modulus in the in-plane direction was obtained. The polyphenylene sulfide film roll obtained in this comparative example is suitable for high-quality applications such as high-frequency circuit boards, because there are many missing coating materials and large variations in warpage in the in-plane direction after punching. may not be used for

Claims (9)

At least one surface has a center plane average roughness SRa of 150 nm or less, and the number of protrusions exceeding 50 nm from the center plane of the film SPc (50 nm) is 5/0.2 mm ² or more (the surface 0° to 45°, 90°, 135° from an arbitrary point on the surface of the film in the direction perpendicular to the longitudinal direction A polyphenylene sulfide film having a difference (absolute value) between the maximum value and the minimum value of Young's modulus in the four directions when the Young's modulus is measured in the ° direction of 0.5 GPa or less. 2. The polyphenylene sulfide film according to claim 1, wherein the surface A has a ten-point average roughness SRz of 1300 nm or less. 3. The polyphenylene sulfide film according to claim 1, wherein the layer A contains substantially no particles. The A layer contains a polyphenylene sulfide resin (A) as a main component, and contains a thermoplastic resin (B) different from the resin (A), and the thermoplastic resin (B) has an average dispersion diameter of 0.5 μm or more. The polyphenylene sulfide film according to any one of claims 1 to 3, which has a thickness of 0.2 µm or less. 5. The polyphenylene sulfide film according to claim 4, wherein the thermoplastic resin (B) contains any one of the following chemical formulas.

(where R ₁ to R ₆ in the formula are each H, OH group, methoxy group, ethoxy group, trifluoromethyl group, aliphatic group having 1 to 13 carbon atoms, or aromatic group having 6 to 10 carbon atoms). or.) The polyphenylene sulfide film according to claim 4 or 5, wherein said thermoplastic resin (B) has a sulfonyl group. When the total content of the resin (A) and the thermoplastic resin (B) in the layer A is 100 parts by mass, the content of the thermoplastic resin (B) is 0.1 parts by mass or more and 50 parts by mass or less. The polyphenylene sulfide film according to any one of claims 4 to 6, wherein Dimensional change rate of 250° C.×10 minutes in 0° and 90° directions from an arbitrary point on the surface of the polyphenylene sulfide film is 5.0% or less. 8. The polyphenylene sulfide film according to any one of 1 to 7. The polyphenylene sulfide film according to any one of claims 1 to 8, wherein the thickness of the polyphenylene sulfide film is 10 µm or more and 500 µm or less.