KR102393034B1 - Polystylene-based film and multilayer film - Google Patents

Abstract

The present invention provides a polystyrene-based film having a more inexpensive rough surface.
It is a polystyrene-based film containing a syndiotactic polystyrene-based resin and a spherical filler, biaxially oriented, having a gloss of 30% or less, a surface roughness (Ra) of 0.8 µm or more, and a tensile elongation of 15% or more. Preferably, the said spherical filler is amorphous silica, More preferably, the said spherical filler is fused silica.

Description

Polystyrene-based film and multilayer film

The present invention relates to a biaxially oriented syndiotactic polystyrene film having a rough surface. Further, the present invention relates to a multilayer film having a biaxially oriented syndiotactic polystyrene-based resin layer having a rough surface as an outermost layer.

Since syndiotactic polystyrene (SPS)-based resins are excellent in heat resistance and chemical resistance, their use is expanding in various fields as molded articles and films. As one of such uses, when manufacturing printed circuit boards, ceramic electronic parts, semiconductor packages, and other various resin molded articles by using the characteristics of SPS-based resins, such as low surface tension and low wettability, molding molds or molding rolls The use of a biaxially oriented SPS-based film for a release film for preventing fusion of a material to be molded with and with a material to be molded has been studied. Patent Documents 1 to 3 describe single-layer or multi-layer release films using SPS-based resins.

In addition, in such a release film, in order to impart a matt tone DML appearance to the surface of the molded article, the release film is roughened and the surface irregularities are sometimes transferred to the molded article. In Patent Documents 4 and 5, by passing a biaxially oriented SPS-based film between a roll having a matt tone surface and another roll while heating and pressurizing the surface, the unevenness of the roll surface is transferred to the film surface, and the film is roughened. that is described. Patent Document 6 describes an SPS-based film roughened by melting and kneading an SPS-based resin and polycarbonate to form a film, and biaxially stretching. Patent Document 7 describes an SPS-based film roughened by melting and kneading an SPS-based resin and a styrene-based thermoplastic elastomer to form a film, and biaxially stretching.

Japanese Laid-Open Patent Publication No. 2001-168117 Japanese Laid-Open Patent Publication No. 2001-310428 Japanese Laid-Open Patent Publication No. 2014-226785 Japanese Laid-Open Patent Publication No. 2013-216779 Japanese Laid-Open Patent Publication No. 2013-215989 Japanese Laid-Open Patent Publication No. 2016-000467 Japanese Laid-Open Patent Publication No. 2011-000468

In the method of roughening by roll transfer as described in patent documents 4 and 5, since a roughening process is required separately from the orientation process of a film, there existed room for improvement in terms of manufacturing cost.

On the other hand, in the method of mixing SPS and another resin and biaxial stretching of patent documents 6 and 7, manufacturing cost can be reduced. However, since the surface unevenness as large as that of the roll transfer method cannot be obtained, the texture is slightly different even at the same gloss level as that of the roll transfer method, and some users have requested adjustment of the texture by increasing the surface unevenness.

Moreover, the present inventors tried roughening of the surface of an SPS-type film by mix|blending a filler in the past. However, in that case, since the film strength fell remarkably by compounding of a filler, the addition amount of a filler was restrict|limited, and it was difficult to strengthen the grade of the mattone of a film (paragraph 0009 of patent document 4).

The present invention has been made in view of the above, and an object of the present invention is to provide a biaxially oriented SPS-based film having a roughened surface, having a large surface unevenness, and being cheaper.

In order to solve the said subject, in this invention, the surface is roughened by mix|blending a spherical filler with SPS-type resin and making it biaxially orientate.

Specifically, the polystyrene-based film of the present invention contains a syndiotactic polystyrene-based resin and a spherical filler, is biaxially oriented, has a glossiness of 30% or less, a surface roughness (Ra) of 0.8 μm or more, and a tensile elongation of 15 % or more

Here, the glossiness refers to a 60 degree specular gloss, Gs (60°) specified in JISZ8741:1997. In addition, the glossiness in the present invention uses the average value of the values in the longitudinal direction (MD) and the transverse direction (TD). The surface roughness (Ra) refers to the arithmetic mean roughness (Ra) specified in JISB0601:1994. Tensile elongation refers to the tensile failure strain (without yielding) or tensile failure nominal strain (with yielding) according to the tensile test (specimen type 2, test speed 200 mm/min) specified in JISK7127:1999. say The tensile elongation of the film of the present invention is 15% or more, respectively, in either the longitudinal direction (MD) and the transverse direction (TD).

With this configuration, a polystyrene-based film having surface unevenness and gloss equivalent to that of the conventional roll transfer method can be obtained without excessively impairing the mechanical properties of the film.

Preferably, the spherical filler is amorphous silica, and more preferably, the spherical filler is fused silica.

In addition, preferably, the maximum diameter of the spherical filler is less than the thickness of the polystyrene-based film, and the median diameter (d50) is 6% or more of the thickness of the polystyrene-based film. Here, the median diameter d50 is a value on a volume basis.

Moreover, Preferably, the compounding quantity of the said spherical filler is 5 weight part or more and 20 weight part or less with respect to 100 weight part of resin components.

The multilayer film of the present invention constitutes a first surface having a glossiness of 30% or less and a surface roughness (Ra) of 0.8 µm or more, and contains a syndiotactic polystyrene-based resin and a spherical filler, and a biaxially oriented first layer and , at least one resin layer provided on a side opposite to the first surface of the first layer. And, when the tensile elongation is 15% or more and the tensile strain is less than 15%, the first layer does not break.

By this structure, the multilayer film which has the surface unevenness|corrugation and glossiness equivalent to the conventional roll transfer method on the 1st surface is obtained. In addition, it becomes possible to realize various properties required for the multilayer film by dividing the first layer and the other layers, and it becomes easier to optimize the surface asperity of the first layer and the texture of the appearance.

Preferably, the resin layer adjacent to the first layer is made of the same syndiotactic polystyrene resin as the first layer, and the content of the spherical filler is less than that of the first layer or does not contain the spherical filler.

Further, preferably, the second surface opposite to the first surface is constituted by the antistatic layer.

According to the present invention, since the syndiotactic polystyrene-based film or the syndiotactic polystyrene-based resin layer is roughened by blending the filler and biaxially oriented, a film having a rough surface can be obtained at a lower cost compared to the conventional roll transfer method. can In addition, since the filler is spherical, a polystyrene-based single-layer film or multi-layer film having surface unevenness and gloss equivalent to that of the conventional roll transfer method is obtained with little decrease in mechanical properties of the film and sufficient tensile elongation maintained. .

BRIEF DESCRIPTION OF THE DRAWINGS It is an example of the cross-sectional structural diagram of the multilayer film of 2nd Embodiment of this invention.
It is another example of the cross-sectional structural diagram of the multilayer film of 2nd Embodiment of this invention.

The polystyrene-based film of the first embodiment of the present invention is a single-layer release film in which a surface is roughened by mixing a spherical filler with a syndiotactic polystyrene (SPS)-based resin and biaxially stretching.

First, the composition of the film of this embodiment is demonstrated.

The SPS-based resin is a styrenic polymer having a syndiotactic structure. The syndiotactic structure refers to a stereochemical structure in which phenyl groups or substituted phenyl groups, which are side chains, are alternately positioned in opposite directions to a main chain formed from a syndiotactic structure, that is, a carbon-carbon bond.

The degree of stereoregularity (tacticity) of the SPS-based resin can be quantified by nuclear magnetic resonance (13C-NMR method) using isotope carbon. The tacticity of the SPS-based resin measured by the 13C-NMR method is a chain consisting of several monomer units, for example, a dyad in the case of two, a triad in the case of three, and a pentad in the case of five. , can be expressed by the ratio of those that are syndiotactic (such as racemic dyad) in which the three-dimensional arrangement of the constituent units is opposite. The SPS-based resin in the present invention is usually 75% or more, preferably 85% or more in racemic dyad, or 60% or more, preferably 75% or more in racemic triad, preferably racemic pentad. It is a styrenic polymer having a syndiotacticity of 30% or more, preferably 50% or more.

As the type of the styrenic polymer as the SPS-based resin, polystyrene, poly(alkylstyrene), poly(halogenated styrene), poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinylbenzoic acid ester), hydrogenated polymers thereof, etc. and a mixture thereof or a copolymer having these as a main component. As poly(alkylstyrene), poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tertiary butylstyrene), poly(phenylstyrene), poly(vinylnaphthalene), poly(vinylstyrene) and the like. Examples of the poly(halogenated styrene) include poly(chlorostyrene), poly(bromostyrene), and poly(fluorostyrene). Poly(chloromethylstyrene) etc. are mentioned as poly(halogenated alkyl styrene). Poly(methoxystyrene), poly(ethoxystyrene), etc. are mentioned as poly(alkoxy styrene).

The weight average molecular weight of the SPS-based resin constituting the plastic film according to the present invention is 10,000 to 3,000,000, preferably 30,000 to 1,500,000, particularly preferably 50,000 to 500,000. The glass transition temperature of the SPS-based resin is 60 ~ 140 ℃, preferably 70 ~ 130 ℃. The melting point of the SPS-based resin is 200 to 320 °C, preferably 220 to 280 °C. In the present specification, values measured according to JISK7121 are used for the glass transition temperature and melting point of the resin.

The SPS-based resin contained in the film of the present embodiment may be a mixture of two or more other SPS-based resins.

The film of this embodiment may contain other resin within the range which does not give practically a bad influence to the heat resistance, chemical resistance, low surface tension, etc. which are the characteristics of an SPS-type film. Even in that case, the content of the SPS-based resin with respect to all the resin components in the film is preferably 50% by weight or more, more preferably 60% by weight or more, and particularly preferably 75% by weight or more.

For example, the film of the present embodiment may contain a styrenic thermoplastic elastomer (TPS). In TPS, the hard segment of the thermoplastic elastomer (TPE) is made of polystyrene, and thus, when it is blended with the SPS-based film, it is difficult to show defects in appearance. By blending TPS, the flexibility of the film is improved. In addition, as described in Patent Document 7, since a roughened SPS-based film is obtained even by biaxially mixing TPS with SPS-based resin, in this embodiment, with the effect of a spherical filler, the matt tone of the film The degree can be made stronger.

When blending TPS, it is preferable to use a hydrogenated one. Thereby, the heat resistance of the TSP is improved, and it is possible to prevent an unexpected reaction from occurring in the melting/extrusion process of the SPS-based resin carried out at a high temperature.

As hydrogenated TPS, polystyrene-poly(ethylene/butyrene)-polystyrene (TPS-SEBS), polystyrene-poly(ethylene/propylene)-polystyrene (TPS-SEPS), polystyrene-poly(ethylene-ethylene/propylene)-polystyrene ( TSP-SEEPS), polystyrene-poly(ethylene/propylene)-polystyrene (TPS-SEP), and the like can be used of various types having different soft segments.

The TPS contained in the film of this embodiment may be what mixed 2 or more types of other TPS. In this case, all or part of the TPS may have a soft segment composed of a poly(ethylene/propylene) block or a poly(ethylene-ethylene/propylene) random copolymer block. When it is desired to increase the roughening effect of a film, it is good to use TPS-SEEPS in which the soft segment consists of a random copolymer of poly(ethylene-ethylene/propylene) for all or part of TPS.

It is preferable that the weight ratio of the SPS-based resin (a) to the TPS (b) is (a)/(b) = 100/0 to 60/40, and further, to 100/0 to 80/20 in the amount of TPS to be blended. more preferably. The effect of roughening and the effect of a flexibility improvement are acquired, so that there are many compounding quantities of TPS. On the other hand, when there is too much compounding quantity of TPS, characteristics, such as heat resistance, chemical-resistance, and low surface tension, which are characteristics of SPS-type resin, will fall.

The filler mix|blended with the film of this embodiment is a spherical filler. When a filler is spherical, fluidity|liquidity is good and it is easy to be highly filled in resin. In addition, since the filler is spherical and stable even if a force is applied from any direction, there is little decrease in the mechanical properties of the film, and it is unlikely that the filler is broken and detached from the film. The sphericity of the spherical filler is preferably 0.80 or more, more preferably 0.90 or more, and particularly preferably 0.95 or more.

The spherical filler is preferably amorphous silica. This is because amorphous silica does not have an excessively high hardness, so it is difficult to wear a screw or a mold of an extruder during film production. Further, the amorphous silica used as the spherical filler is preferably an amorphous silica that is not porous. For example, when the amorphous silica is derived from silica gel, it is preferable to use the non-porous silica by calcination.

Another example of amorphous silica that is not porous is fused silica. Because fused silica is spheroidized by surface tension by melting the raw material in a flame, there is no sharp part, the fluidity in the resin is higher, it is more difficult to break, and the degree of impairing the mechanical properties of the film is less. . In addition, when the film of this embodiment is used as a release film of a semiconductor package, fused silica is also contained in the epoxy resin which is a to-be-molded material, and it is hard to become a problem even if it transfers to a to-be-molded material.

The largest particle diameter of the spherical filler is preferably less than the thickness of the film, more preferably 95% or less of the film thickness, and still more preferably 65% or less of the film thickness. This is because, when a spherical filler having a diameter close to or larger than the thickness of the film is contained, the film is likely to break in that portion and the mechanical properties of the film are deteriorated. It is preferable that the diameter of the largest thing of a spherical filler is 40 % or more of film thickness, if it is to provide surface unevenness|corrugation with a texture more.

Further, the median diameter (d50) of the spherical filler is preferably 6% or more of the film thickness, more preferably 10% or more of the film thickness, and particularly preferably 20% or more of the film thickness. This is because, when the particle diameter of the filler is too small, the surface unevenness of a sufficient size cannot be obtained. On the other hand, the median diameter (d50) of the spherical filler is preferably 60% or less of the film thickness, more preferably 40% or less of the film thickness. It is because the fall of the mechanical property of a film becomes large when the median diameter of a filler is too large. It is preferable that the median diameter (d50) of a spherical filler exists in the range of 15 to 35% of the film thickness as long as it provides surface unevenness|corrugation with a texture more. In addition, in this specification, the median diameter (d50) is a value on a volume basis. This value corresponds to the value on a mass basis or a weight basis if the filler is made of a single material and has a constant density.

To [ the compounding quantity of a spherical filler / 100 weight part of resin components of a film ], Preferably it is 5 weight part or more, More preferably, it is 10 weight part or more. This is to obtain surface irregularities of sufficient size. On the other hand, preferably the compounding quantity of a spherical filler is 20 weight part or less with respect to 100 weight part of resin components of a film. It is because the fall of the mechanical property of a film will become large when there are too many compounding quantities.

The film of the present embodiment may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, colorants, nucleating agents, and flame retardants in addition to the above-described polymers according to required characteristics. In particular, it is preferable that an antioxidant and a lubricant are added to the film used as the release film. Moreover, it is preferable that the antistatic agent is added to the film used as a release film, or that antistatic agents, such as surfactant, are coated on the surface of one side.

Next, the characteristics of the film of this embodiment are demonstrated.

The thickness of the film is preferably 10 to 100 µm from the viewpoint of being able to respond to many uses and easiness of manufacture and handling. The thickness of the biaxially oriented film used as the release film is typically 40 to 100 μm, most typically about 50 μm.

The glossiness of the film is expressed by the 60 degree specular gloss, Gs (60°) specified in JISZ8741:1997. The glossiness required for the film is determined according to the use, and in order to impart a matte appearance without feeling "greasiness" on the surface of the molded article, it is 30% or less, preferably 20% or less. In addition, although a lower limit does not have a meaning in particular, it is usually 1 % or more.

The surface roughness (Ra) of the film is expressed by the arithmetic mean roughness (Ra) specified in JISB0601:1994. In order to impart a texture similar to the roll transfer method to the appearance of the matte tone of the film, the surface roughness (Ra) is 0.8 µm or more, preferably 1.0 µm or more. On the other hand, Ra is preferably 3.5 µm or less, and more preferably 3.0 µm or less. This is because when Ra is too large, the to-be-molded resin cannot fully follow the deep unevenness|corrugation, and a stable molded article surface cannot be obtained. In addition, when Ra is too large, it is because the deviation from the texture of the surface by the roll transfer method becomes large.

The tensile elongation of the film refers to the tensile fracture strain or the tensile fracture nominal strain by the tensile test (specimen type 2, test speed 200 mm/min) specified in JISK7127: 1999. Tensile elongation refers to the nominal strain at tensile failure, since when the film is made of SPS it is subject to yielding in tensile testing. The tensile elongation of the film is 15% or more in both the longitudinal direction (MD) and the transverse direction (TD) at room temperature (23±2° C., 50±10% relative humidity), and preferably 20% or more. On the other hand, although there is no problem in particular even if the tensile elongation of a film is too large, in this embodiment, since SPS is a main component, it generally does not exceed 200 %.

Next, the manufacturing method of the film of this embodiment is demonstrated.

The film of this embodiment mixes SPS-based resin, spherical filler, and other materials, melts and kneads, extrudes to produce a precursor film (raw film before stretching), and then biaxially stretches the obtained precursor film. can be manufactured.

A known method may be employed for the method for producing the precursor film. For example, what is necessary is just to melt and knead the mixture which consists of a desired component with an extruder, and to extrude a kneaded material from a T-die, and just to cool it.

A biaxial stretching process is a process of extending|stretching with respect to the biaxial direction of a film, and then optionally heat-setting. By this biaxial stretching process, the SPS-based resin is crystallized, and the glass transition temperature of the film is increased to improve heat resistance and improve mechanical strength. Moreover, the surface unevenness|corrugation increases with the film of this embodiment by a biaxial stretching process.

Biaxial stretching extends|stretches with respect to the MD direction and TD direction of a film. The stretching method includes a sequential biaxial stretching method and a simultaneous biaxial stretching method. Since heat resistance dimensional stability and tensile elongation can be further improved, the simultaneous biaxial stretching method is preferable. For example, according to the simultaneous biaxial stretching system, the difference between the MD direction and TD direction of the absolute value of thermal contraction rate can be made small easily. When carrying out biaxial stretching, the draw ratio, extending|stretching temperature, and extending|stretching speed|rate can select suitable conditions for obtaining desired heat-resistant dimensional stability, mechanical properties, etc.

Heat setting is a process for fixing the orientation of polymer molecules by maintaining the stretched film at a temperature equal to or higher than the stretching temperature. As for the heat treatment temperature, time, and relaxation magnification, conditions suitable for obtaining a desired thermal shrinkage rate and the like can be selected.

Next, the multilayer film of 2nd Embodiment of this invention is demonstrated.

In the first embodiment, the characteristics of a biaxially oriented film containing a syndiotactic polystyrene (SPS)-based resin and a spherical filler that the glossiness is 30% or less and the surface roughness (Ra) is 0.8 µm or more are the characteristics of the biaxially oriented film is the surface characteristic of the film, and the characteristic that the tensile elongation is 15% or more is the characteristic of the film itself, that is, as a release film. In the multilayer film, at least one surface of the multilayer film has a biaxially oriented film layer containing an SPS-based resin having a glossiness of 30% or less and a surface roughness (Ra) of 0.8 µm or more and a spherical filler. If the tensile elongation of the biaxially oriented film layer is 15% or more, it can be used as a single layer of the biaxially oriented film, or can be used as a multilayer film by adding another layer. If the tensile elongation of the said biaxially oriented film layer is less than 15 %, it is good if the tensile elongation can express 15 % or more as a multilayer film by adding another layer. Alternatively, another layer having a function such as antistatic property may be added to form a multilayer film.

In the example shown in FIG. 1 , the multilayer film 10 consists of two layers, a first layer 11 constituting a first surface 15 and a second surface 16 adjacent the first layer. of the second layer 12 constituting the

The composition and properties of the first layer 11 are the same as those of the polystyrene-based film of the first embodiment. That is, the first layer contains a syndiotactic polystyrene (SPS)-based resin and a spherical filler and is biaxially oriented. The first surface 15 has a glossiness of 30% or less and a surface roughness Ra of 0.8 μm or more. In addition, the first layer requires that the tensile strain of the multilayer film 10 does not break when less than 15%, and preferably does not break when the tensile strain of the multilayer film 10 is less than 20%. A preferred composition of the SPS-based resin contained in the first layer, a preferred material for the spherical filler, a particle diameter, a compounding amount, and the like are also the same as in the first embodiment. Here, the preferable particle diameter of a spherical filler is determined relatively with respect to the thickness of a 1st layer, similarly to what was determined relatively with respect to the thickness of a single|monolayer film in 1st Embodiment.

The resin forming the second layer 12 is not particularly limited, and desired properties are obtained from polyolefin resins such as SPS resins, polyethylene and polypropylene, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. You can choose what you have and use it. When the mechanical properties of the multilayer film 10 are improved by the second layer, the second layer is preferably made of an SPS-based resin, and more preferably made of the same SPS-based resin as the first layer. This is because, as will be described later, it is easy to manufacture by co-extrusion. When a 2nd layer consists of SPS resin, it is preferable that content of the spherical filler of a 2nd layer is less than a 1st layer, and it is more preferable that a 2nd layer does not contain a spherical filler. Thereby, the 2nd layer can be made into the layer excellent in mechanical properties than the 1st layer.

Alternatively, the second layer 12 may be an antistatic layer. The antistatic layer may be one in which an antistatic agent is blended with the resin serving as the matrix, or may be a layer made of a conductive resin. When the multilayer film 10 is used as a mold release film for resin molding because the second surface 16 is constituted by an antistatic layer, by using the first surface 15 toward the molded resin side, a matte tone is applied to the surface of the resin molded article. can be imparted, and at that time, since the second surface 16 is in contact with the mold, charging of the multilayer film 10 can be prevented.

In the example illustrated in FIG. 2 , the multilayer film 20 is composed of three layers, a first layer 11 constituting the first surface 15 , a second layer 22 adjacent to the first layer, and , a third layer 23 constituting the second surface 26 . The first layer of FIG. 2 is the same as the first layer of FIG. 1 .

The resin for forming the second layer 22 and the third layer 23 is not particularly limited, and one having desired properties may be selected and used. As an example, the second layer may be formed of the same SPS-based resin as the first layer, but may be a layer that does not contain a spherical filler, and the third layer may be an antistatic layer. As another example, if the second layer is formed of the same SPS-based resin as the first layer, but does not contain a spherical filler, and the third layer is composed of the same layer as the first layer, the cross section becomes a symmetrical structure , a multilayer film in which the first surface and the second surface are roughened identically is obtained.

The layer constitution of the multilayer film is not limited to the above. The number of floors can be made into the arbitrary number of two or more floors. Since the glossiness and surface roughness (Ra) of the first surface are realized by the first layer, the composition and function of each layer other than the first layer can be arbitrarily determined.

Next, the manufacturing method of the multilayer film of this embodiment is demonstrated.

After forming each layer as an independent film, the multilayer film of this embodiment may bond through an adhesive layer. For example, the polystyrene-based film of the first embodiment can be used as the first layer 11 to be bonded to another film.

Alternatively, when the softening temperatures or viscosity curves of a plurality of resins are close, the resins may be co-extruded to form several layers at the same time. For example, when the first layer 11 and the second layer adjacent thereto are made of the same SPS-based resin, each raw material is melted and kneaded to form a two-layered precursor film by co-extrusion, By performing biaxial stretching, a 1st layer and a 2nd layer can be formed simultaneously.

Alternatively, a new layer may be formed by coating a resin raw material on the surface of another film. For example, the thickness of the antistatic layer is generally 0.1 mu m or less, and it is difficult to form such a thin layer as a single film. In this case, an antistatic layer may be formed by applying a conductive resin to the second surface of another single-layer or multi-layer film and drying or crosslinking.

When a film is multilayered like this embodiment, the effect that the freedom degree of film design becomes large is acquired. In a single-layer SPS-based film, when the surface roughness is increased, the tensile elongation tends to decrease. In contrast, in the multilayer film, the composition of the first layer can be adjusted to optimize the surface asperity and texture by realizing the required mechanical properties and the like in a layer other than the first layer.

[Example]

Examples of the polystyrene-based film of the first embodiment will be described.

The films of Examples were prepared as follows. As the SPS-based resin, a syndiotactic polystyrene (SPS) resin (manufactured by Idemitsu Kosan Co., Ltd., Zarec 142ZE (glass transition temperature 95°C, melting point 247°C)) was used. A predetermined spherical filler was mixed with SPS in a predetermined ratio, kneaded, and melt-extruded at 290°C using an extruder equipped with a T-die at the tip, followed by cooling to obtain a precursor film. This precursor film was simultaneously biaxially stretched at a predetermined magnification at 110 DEG C and a stretching rate of about 500%/min. After stretching, the film was heat-set at 210° C. at a relaxation magnification of 0.95 times in the longitudinal direction (MD) and 0.95 times in the transverse direction (TD) to obtain a simultaneous biaxially stretched SPS-based film with a thickness of about 50 μm.

The film of Comparative Example 1 did not mix|blend a spherical filler, and produced the SPS-type film by the method similar to Example. For the film of Comparative Example 2, an SPS-based film having a thickness of 50 μm was prepared without stretching treatment by melting and extrusion by blending a spherical filler with SPS. For the film of Comparative Example 3, an SPS-based film was produced in the same manner as in Example.

Table 1 shows the type of spherical filler, particle diameter and compounding amount, draw ratio, thickness of the obtained film, gloss, surface roughness (Ra), and tensile elongation.

The types, part numbers, and manufacturers of spherical fillers indicated by each symbol in Table 1 are as follows.

· F5: Silica, FB-5SDC, Denka Corporation

· F7: Silica, FB-7SDC, Denka Corporation

· H: Silica, HS-207, New Nittetsu Sumikin Material Rouge Co., Ltd.

· FE: Silica, FEB25A-SQ Co., Ltd. Adomatech

· K: Silica, KSE-2045 Kinsei Matech Co., Ltd.

· N: Silica, NP-100, AGC SI Tech Co., Ltd.

· S: Aluminosilicate, Sirton JC-50, Mizusawa Chemical Co., Ltd.

Any spherical filler is amorphous. In addition, spherical fillers "F5", "F7", "H", "FE", and "K" are fused silica, and "N" is a thing which baked the spherical silica gel and made it nonporous.

The glossiness in Table 1 is 60 degree mirror gloss, Gs (60 degree) prescribed|regulated to JISZ8741:1997, and was measured using the glossmeter (Unigross 60, Konica Minolta Corporation). The surface roughness (Ra) is the arithmetic mean roughness (Ra) prescribed|regulated to JIS B0601:1994, and was measured using the surface roughness measuring instrument (Handysurf, Tokyo Seimitsu Co., Ltd.). The tensile elongation was determined by the method specified in JIS K7127: 1999, and the tensile failure nominal strain was obtained from the stress/strain curve measured at a test speed of 200 mm/min at test piece type 2 and 200 mm/min.

Comparing Comparative Example 1 and Examples 1 to 10, it can be seen that in the film of Example, the gloss is low, the surface roughness (Ra) is large, and the film surface is roughened. Moreover, in the film of an Example, it was confirmed that the matt tone was provided also by visual observation. On the other hand, in the films of Examples 1 to 10, the tensile elongation of the film was lower than that of Comparative Example 1, but in any Example, it was maintained at 15% or more, and the decrease in mechanical properties due to the blending of the spherical filler was practically sufficient. It can be seen that it is suppressed by

Comparing Comparative Example 2 and Example 6, in the unstretched Comparative Example 2, the gloss was low and the surface roughness (Ra) was large, but the tensile elongation was small. In Example 6 which was biaxially stretched, the glossiness was lower, the surface roughness (Ra) became larger, and the tensile elongation sufficient for practical use was obtained.

Comparing Comparative Example 3 and Examples 1 to 10, in Comparative Example 3 using fused silica having a large particle diameter, a larger surface roughness (Ra) than in Example was obtained, but the tensile elongation was small. This is considered to be because the fused silica of Comparative Example 3 contained particles having a maximum particle diameter of 67 μm with respect to a film thickness of 50 μm, and thus the film was fractured by smaller stretching.

Next, examples of the multilayer film of the second embodiment will be described.

The composition of the first layer was the same as in Example 8. It was used for the 2nd layer, without mix|blending a spherical filler with SPS similar to the 1st layer. The raw materials for the first layer and the second layer were respectively kneaded, melt co-extruded at 290°C using a two-layer molding extruder, and cooled to obtain a precursor two-layer film. This precursor two-layer film was simultaneously biaxially stretched and heat-set under the same conditions as in Examples 1 to 10 to obtain simultaneous biaxially stretched SPS-based two-layer films of Examples 11 and 12.

In Table 2, the manufacturing conditions, thickness, and 1st surface glossiness and surface roughness (Ra), and tensile elongation of the two-layer film of Example 11 and Example 12 are shown.

From Table 2, it can be seen that Examples 11 and 12 have a first surface of the same glossiness and surface roughness (Ra) as Example 8, and have a tensile elongation greater than Example 8. In addition, in the measurement of the tensile elongation of Examples 11 and 12, the first layer did not break until the two-layer film broke.

The present invention is not limited to the above embodiments or examples, and various modifications are possible within the scope of the technical idea.

The roughened polystyrene-based film and multilayer film of the present invention are particularly useful as a release film for molding, such as an epoxy resin printed circuit board, particularly a release film (transfer film) having a transfer function, but the use thereof is not limited thereto. In addition to the use as a release film, it is useful for various uses which require a rough surface. Further, even when used as a release film, the type of plastic constituting the material to be molded is not particularly limited, and for example, an epoxy resin, a phenol resin, a melamine resin, a urea resin, an alkyd resin, a polyimide resin, a poly It can be used for molding ester resins, polyurethane resins, acrylic resins, and the like.

10, 20: multilayer film 11: first layer
12, 22: second layer 23: third layer
15: first surface 16, 26: second surface

Claims (9)

It contains a syndiotactic polystyrene-based resin and a spherical filler,
biaxially oriented,
The glossiness is 30% or less, the surface roughness (Ra) is 0.8 μm or more, and the tensile elongation is 15% or more,
The blending amount of the spherical filler is 5 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the resin component,
The spherical filler is silica or aluminosilicate, polystyrene-based film. The method of claim 1,
The spherical filler is amorphous silica, a polystyrene-based film. 3. The method of claim 2,
The polystyrene-based film wherein the spherical filler is fused silica. 4. The method according to any one of claims 1 to 3,
The maximum diameter of the spherical filler is less than the thickness of the polystyrene-based film, and the median diameter (d50) is 6% or more of the thickness of the polystyrene-based film, the polystyrene-based film. delete delete A first surface having a glossiness of 30% or less and a surface roughness (Ra) of 0.8 µm or more is included, and contains a syndiotactic polystyrene-based resin and a spherical filler, and the blending amount of the spherical filler is 100 parts by weight of the resin component. 5 parts by weight or more and 20 parts by weight or less, wherein the spherical filler is silica or an aluminosilicate, and a biaxially oriented first layer;
at least one resin layer provided on a side opposite to the first surface of the first layer;
The multilayer film, wherein the first layer does not break when the tensile elongation is 15% or more and the tensile strain is less than 15%. 8. The method of claim 7,
A resin layer adjacent to the first layer is made of the same syndiotactic polystyrene-based resin as that of the first layer, and the content of the spherical filler is less than that of the first layer or does not contain a spherical filler. . 9. The method according to claim 7 or 8,
wherein the second surface opposite to the first surface is constituted by an antistatic layer.

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