TWI744412B - Polystyrene film and multilayer film - Google Patents

Abstract

The present invention provides a polystyrene-based film and a multilayer film with a rough surface at a lower price. A polystyrene film containing syndiotactic polystyrene resin and spherical fillers, biaxially aligned, gloss is 30% or less, surface roughness (Ra) is 0.8 μm or more, and tensile elongation is 15 %above. Preferably, the spherical filler is amorphous silica, and more preferably, the spherical filler is fused silica.

Description

Polystyrene film and multilayer film

The present invention relates to a biaxially aligned syndiotactic polystyrene film with a rough surface. In addition, the present invention relates to a multilayer film including a biaxially aligned syndiotactic polystyrene resin layer with a rough surface on the outermost layer.

Syndiotactic polystyrene (SPS)-based resins are excellent in heat resistance and chemical resistance, etc., so they have expanded their use in various fields as molded products or films. As one of such applications, research has been conducted on the use of SPS resins with low surface tension and low wettability in the manufacture of printed circuit boards, ceramic electronic parts, semiconductor packages, and various other resin molded products. A biaxially aligned SPS-based film is used for the release film of the fusion of the forming die or the forming roll and the material to be formed. Patent Document 1 to Patent Document 3 describe a single-layer or multilayer release film using an SPS-based resin.

In addition, in the release film, in order to impart a matte appearance to the surface of the molded article, the release film may be roughened, and the surface irregularities may be transferred to the molded article. Patent Document 4 and Patent Document 5 describe that the biaxially oriented SPS film is heated and pressurized and passed between a roller with a matt pattern on the surface and other rollers, thereby reducing the unevenness on the surface of the roller. Transfer to the film surface to roughen the film. Patent Document 6 describes an SPS-based film that is formed by melting and kneading an SPS-based resin and polycarbonate, forming a film, biaxially stretching, and roughening. Patent Document 7 describes an SPS-based film which is formed by melting and kneading an SPS-based resin and a styrene-based thermoplastic elastomer, forming a film, biaxially stretching, and roughening. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2001-168117 [Patent Document 2] Japanese Patent Application Publication No. 2001-310428 [Patent Document 3] Japanese Patent Application Publication No. 2014-226785 [Patent Document 4] Japanese Patent Publication Open 2013-216779 [Patent Document 5] Japanese Patent Laid-Open No. 2013-215989 [Patent Document 6] Japanese Patent Laid-Open No. 2016-000467 [Patent Document 7] Japanese Patent Laid-Open No. 2011-000468

[Problems to be Solved by the Invention] In the method of roughening by roll transfer as described in Patent Document 4 and Patent Document 5, an alignment step of the film and an additional roughening step are required, so there is a manufacturing cost aspect. There is room for improvement.

In contrast, in the method of mixing SPS with other resins and performing biaxial stretching described in Patent Document 6 and Patent Document 7, the manufacturing cost can be reduced. However, it is not possible to obtain a large surface unevenness in the roll transfer method. Therefore, even with the same glossiness as the roll transfer method, the texture is slightly different, and some users require adjustment of the texture caused by the increase in surface unevenness.

In addition, the inventors of the present invention have previously tried to roughen the surface of the SPS-based film by blending fillers. However, at this time, the strength of the film is significantly reduced by compounding the filler, so the amount of filler added is limited, and it is difficult to enhance the degree of matt feeling of the film (Patent Document 4, paragraph 0009).

The present invention is made in consideration of the above circumstances, and its object is to provide a biaxially aligned SPS-based film with a roughened surface, that is, a film with large surface irregularities and a lower cost. [Technical means to solve the problem]

In order to solve the above-mentioned problem, in the present invention, the surface is roughened by blending the spherical filler in the SPS-based resin and performing biaxial alignment.

Specifically, the polystyrene-based film of the present invention contains syndiotactic polystyrene-based resin and spherical fillers, biaxially aligned, gloss is 30% or less, surface roughness (Ra) is 0.8 μm or more, and stretched The elongation is more than 15%.

Here, the term “glossiness” refers to the 60-degree specular gloss and Gs (60°) specified in the Japanese Industrial Standards (JIS) Z8741: 1997. In addition, the glossiness in the present invention uses the average value of the values in the vertical direction (Machine Direction, MD) and the horizontal direction (Transverse Direction, TD). The so-called surface roughness (Ra) refers to the arithmetic average roughness Ra specified in JISB0601:1994. The so-called tensile elongation refers to the tensile failure strain (without yield) or nominal tensile failure obtained from the tensile test (test piece type 2, test speed 200 mm/min) specified in JISK7127: 1999 Strain (when accompanied by yield). The tensile elongation of the film of the present invention is 15% or more in each of the longitudinal direction (MD) and the lateral direction (TD).

With this configuration, it is possible to obtain a polystyrene-based film having surface irregularities and glossiness equivalent to those of the conventional roll transfer method 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, it is preferable that 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 particle diameter (d50) is a value on a volume basis.

In addition, it is preferable that 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 multilayer film of the present invention includes: the first layer, which constitutes a first surface with a gloss of 30% or less and a surface roughness (Ra) of 0.8 μm or more, contains syndiotactic polystyrene resin and spherical fillers, and has a biaxial Alignment; and at least one resin layer, disposed on the side of the first layer opposite to the first surface. Furthermore, when the tensile elongation is 15% or more and the tensile strain is less than 15%, the first layer does not break.

With this configuration, it is possible to obtain a multilayer film having surface irregularities and gloss on the first surface equivalent to those of the conventional roll transfer method. In addition, the first layer and other layers can be used to share and realize the characteristics required for the multilayer film, so that the surface unevenness or appearance of the first layer can be more easily optimized.

Preferably: the resin layer adjacent to the first layer contains 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 spherical filler.

In addition, it is preferable that the second surface on the side opposite to the first surface is made of an antistatic layer. [Effects of the invention]

According to the present invention, the syndiotactic polystyrene film or the syndiotactic polystyrene resin layer is roughened by compounding fillers and performing biaxial alignment. Therefore, compared with the previous roll transfer method, it can be obtained at a lower cost. A film with a rough surface. Furthermore, because the filler is spherical, it is possible to obtain a polystyrene-based monomer with less reduction in the mechanical properties of the film, and with the same surface unevenness and gloss as the conventional roll transfer method while maintaining sufficient tensile elongation. Layer film or multilayer film.

The polystyrene-based film of the first embodiment of the present invention is a single-layer release formed by blending spherical fillers in a syndiotactic polystyrene (SPS)-based resin and then biaxially extending it to roughen the surface. membrane.

First, the composition of the film of this embodiment will be described.

The SPS-based resin is a styrene polymer having a syndiotactic structure. The term "syndiotactic structure" refers to a three-dimensional structure in which the stereochemical structure is a syndiotactic structure, that is, a phenyl group or substituted phenyl group having a side chain with respect to the main chain formed by a carbon-carbon bond is alternately located in the opposite direction.

The degree of stereoregularity (tacticity) of the SPS-based resin can be quantified by a nuclear magnetic resonance method (13C-NMR method) using isotope carbon. The stereoregularity of the SPS-based resin measured by 13C-NMR method can be obtained by a chain containing a plurality of monomer units, for example, when there are two, it is a doublet (dyad), and when it is three, it is a triplet (triad). ), when it is five, the three-dimensional configuration of the structural unit in the pentad is expressed by the ratio of the opposite syndiotactic (racemic doublet, etc.). The SPS resin in the present invention usually has 75% or more of racemic dimers, preferably 85% or more, or 60% or more of racemic triads, preferably 75% or more, or racemic A styrene-based polymer having a syndiotacticity of 30% or more, preferably 50% or more in terms of pentads.

Regarding the types of styrene-based polymers as SPS-based resins, examples include polystyrene, poly(alkylstyrene), poly(halogenated styrene), poly(halogenated alkylstyrene), and poly(alkoxy). Styrene), poly(vinyl benzoate), hydrogenated polymers of these, and mixtures of these, or copolymers containing these as main components. Examples of poly(alkylstyrene) include: poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tert-butylstyrene), poly(phenyl) Styrene), poly(vinyl naphthalene), poly(vinyl styrene), etc. As poly(halogenated styrene), poly(chlorostyrene), poly(bromostyrene), poly(fluorostyrene), etc. are mentioned. Examples of poly(halogenated alkylstyrene) include poly(chloromethylstyrene) and the like. As poly(alkoxystyrene), poly(methoxystyrene), poly(ethoxystyrene), etc. are mentioned.

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

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

The film of the present embodiment may contain other resins within a range that does not adversely affect the heat resistance, chemical resistance, low surface tension, etc., which are the characteristics of the SPS-based film. In this case, the content ratio of the SPS-based resin with respect to all 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 this embodiment may contain a styrene-based thermoplastic elastomer (Thermo Plastic Styrene Elastomer, TPS). TPS is a thermoplastic elastomer (Thermo Plastics Elastomer, TPE) whose hard segment contains polystyrene. Therefore, when it is formulated in an SPS-based film, appearance defects and the like are unlikely to occur. By blending TPS, the flexibility of the film is improved. Furthermore, by mixing TPS with SPS-based resin and performing biaxial alignment as described in Patent Document 7, a roughened SPS-based film can also be obtained. Therefore, in this embodiment, the effect of the spherical filler is supplemented The degree of matt feeling of the film can be further enhanced.

In the case of preparing TPS, it is preferable to use a hydrogenated one. Thereby, the heat resistance of TPS is improved, and in addition, it is possible to prevent an unexpected reaction from occurring in the step of melting and extruding the SPS-based resin performed at a high temperature.

As hydrogenated TPS, polystyrene-poly(ethylene/butylene)-polystyrene (TPS-SEBS (Styrene-Ethylene/Butylene-Styrene)), polystyrene-poly(ethylene/propylene)-polystyrene can be used (TPS-SEPS (Styrene-Ethylene/Propylene-Styrene)), polystyrene-poly(ethylene-ethylene/propylene)-polystyrene (TPS-SEEPS (Styrene-Ethylene-Ethylene/Propylene-Styrene)) and other soft chains All kinds of different segments.

The TPS contained in the film of this embodiment may be a mixture of two or more different TPSs. At this time, all or part of the TPS may be those in which the soft segment includes a poly(ethylene/propylene) block or a poly(ethylene-ethylene/propylene) random copolymer block. In the case of increasing the roughening effect of the film, in all or part of the TPS, TPS-SEEPS whose soft segment contains a random copolymer of poly(ethylene-ethylene/propylene) can be used.

Regarding the blending amount of TPS, the weight ratio of SPS-based resin (a) and TPS (b) is preferably set to (a)/(b)=100/0 to 60/40, and more preferably set to 100/0 ~80/20. The greater the amount of TPS blended, the more the effect of roughening or the effect of improving flexibility can be obtained. On the other hand, if the blending amount of TPS is too large, the characteristics of the SPS resin, such as heat resistance, chemical resistance, and low surface tension, are reduced.

The filler blended in the film of this embodiment is a spherical filler. Since the filler is spherical, the fluidity is good and it is easy to be highly filled in the resin. In addition, since the filler is spherical, it is stable even if force is applied from any direction. Therefore, the mechanical properties of the film are less deteriorated and it is difficult to cause the filler to be broken and detach 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. The reason is that the hardness of amorphous silicon dioxide is not too high, so the screw or die of the extruder is not easy to wear during film manufacturing. In addition, the amorphous silica used as the spherical filler is preferably non-porous amorphous silica. For example, in the case where the amorphous silicon dioxide is derived from silicon gel, it is preferable to use one made by sintering to make it non-porous.

Another example of non-porous amorphous silica is fused silica. The reason is: Regarding molten silica, the raw material is melted in a flame and spheroidized by surface tension. Therefore, there is no sharp part, and the fluidity in the resin is higher, and it is more difficult to be destroyed, which impairs the mechanical properties of the film. The degree is smaller. Furthermore, when the film of this embodiment is used as a release film for a semiconductor package, the epoxy resin as the material to be molded may also contain molten silica, and even if it migrates to the material to be molded, it is not easy to become problem.

The diameter of the largest of the particle diameters 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. The reason is that if a spherical filler having a diameter close to the film thickness or greater than the film thickness is included, the film is likely to be broken in this portion, and the mechanical properties of the film decrease. In order to impart more textured surface irregularities, the diameter of the largest spherical filler is preferably 40% or more of the film thickness.

In addition, the median particle 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. The reason is that if the particle size of the filler is too small, surface irregularities of 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, and more preferably 40% or less of the film thickness. The reason is that if the median particle diameter of the filler is too large, the decrease in the mechanical properties of the film becomes larger. In order to give a more textured surface unevenness, the median diameter (d50) of the spherical filler is preferably in the range of 15% to 35% of the film thickness. In addition, in this specification, the median diameter (d50) is a value on a volume basis. If the filler contains a single substance and the density is constant, the value is consistent with the value on a mass basis or a weight basis.

The compounding amount of the spherical filler is preferably 5 parts by weight or more, and more preferably 10 parts by weight or more with respect to 100 parts by weight of the resin component of the film. The reason is to obtain sufficient surface irregularities. On the other hand, the compounding amount of the spherical filler is preferably 20 parts by weight or less with respect to 100 parts by weight of the resin component of the film. The reason is that if the blending amount is too large, the mechanical properties of the film decrease.

The film of this embodiment may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, coloring agents, crystal nucleating agents, flame retardants, etc., in addition to the polymer according to the required characteristics. . In particular, it is preferable to add an antioxidant and a lubricant to the film used as a release film. In addition, it is preferable to add an antistatic agent to the film used as a release film or to coat one surface with an antistatic agent such as a surfactant.

Next, the characteristics of the film of this embodiment will be described.

The thickness of the film is preferably 10 μm to 100 μm in terms of being able to cope with a large number of uses and ease of manufacturing or handling. The thickness of the biaxially stretched film used as the release film is typically 40 μm to 100 μm, and most typically about 50 μm.

The gloss of the film is expressed by the 60 degree specular gloss and Gs (60°) specified in JISZ8741:1997. The gloss required for the film depends on the application. In order to give the surface of the molded article a matt appearance without feeling "bright", it is 30% or less, preferably 20% or less. Furthermore, the lower limit is not particularly meaningful, but it is usually 1% or more.

The surface roughness (Ra) of the film is expressed by the arithmetic average roughness Ra specified in JISB0601:1994. In order to give the matt appearance of the film a texture similar to the roll transfer method, 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, more preferably 3.0 μm or less. The reason is that if Ra is too large, the resin to be molded cannot fully follow its large irregularities, and a stable molded product surface cannot be obtained. In addition, the reason is that if Ra is too large, the deviation from the texture of the surface by the roll transfer method becomes large.

The so-called tensile elongation of the film refers to the tensile failure strain or the nominal tensile failure strain obtained from the tensile test (test piece type 2, test speed 200 mm/min) specified in JISK7127: 1999. When the film contains SPS, it is accompanied by yield in the tensile test, so the tensile elongation refers to the nominal strain at tensile failure. The tensile elongation of the film is 15% or more in any of the longitudinal direction (MD) and the transverse direction (TD) at room temperature (23°C±2°C, relative humidity 50%±10%), preferably It is more than 20%. On the other hand, even if the tensile elongation of the film is too large, there is no particular problem. However, in the present embodiment, SPS is used as the main component, so it is usually not more than 200%.

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

The film of this embodiment can be produced by mixing SPS resin, spherical fillers, and other materials, melting, kneading, and extruding to produce a precursor film (pre-stretched roll film). The precursor film is stretched biaxially.

A well-known method can be used for the manufacturing method of the precursor film. For example, what is necessary is just to melt and knead the mixture containing the desired component with an extruder, and to cool the kneaded product after extruding it from a T die.

The biaxial stretching step is a step of stretching with respect to the biaxial direction of the film, and then arbitrarily performing thermal fixation. Through this biaxial stretching step, the SPS-based resin is crystallized, the glass transition temperature of the film is increased, the heat resistance is improved, and the mechanical strength is improved. In addition, the film of the present embodiment has increased surface irregularities through the biaxial stretching step.

Biaxial stretching is stretching in the MD and TD directions of the film. The stretching method includes sequential biaxial stretching and simultaneous biaxial stretching. The simultaneous biaxial stretching method can further improve the heat-resistant dimensional stability or tensile elongation, so it is preferred. For example, according to the simultaneous biaxial stretching method, the difference between the MD direction and the TD direction of the absolute value of the thermal contraction rate can be easily reduced. When performing biaxial stretching, the stretching ratio, stretching temperature, and stretching speed can be selected from suitable conditions for obtaining the desired heat-resistant dimensional stability or mechanical properties.

Thermal fixation is a process of fixing the alignment of polymer molecules by holding the stretched film at a temperature higher than the stretching temperature. The heat treatment temperature, time, and relaxation ratio can be selected from suitable conditions for obtaining the desired heat shrinkage ratio and the like.

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

In the first embodiment, the biaxial alignment film containing syndiotactic polystyrene (SPS) resin and spherical fillers has a gloss of 30% or less and a surface roughness (Ra) of 0.8 μm or more. The surface characteristics of the axis-aligned film, the characteristic with a tensile elongation of 15% or more, are the characteristics of the film itself, that is, the release film. In the multilayer film, at least one surface has a biaxially aligned film layer containing an SPS resin and spherical fillers with a gloss of 30% or less and a surface roughness (Ra) of 0.8 μm or more. Furthermore, if the tensile elongation of the biaxially oriented film layer is 15% or more, the biaxially oriented film can be used as a single layer, or another layer can be added to be used as a multilayer film. If the tensile elongation of the biaxially aligned film layer is less than 15%, another layer is added to form a multilayer film, and the tensile elongation may be 15% or more. Alternatively, another layer having functions such as antistatic properties may be added to form a multilayer film.

In the example shown in FIG. 1, the multilayer film 10 is composed of two layers, including: a first layer 11 that constitutes a first surface 15; and a second layer 12 that is adjacent to the first layer and constitutes a second surface 16.

The composition and characteristics 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 syndiotactic polystyrene (SPS)-based resin and spherical fillers, and is biaxially aligned. Moreover, the glossiness of the first surface 15 is 30% or less, and the surface roughness (Ra) is 0.8 μm or more. In addition, the first layer needs to not break when the tensile strain of the multilayer film 10 is less than 15%, and preferably does not break when the tensile strain is less than 20%. The preferred composition of the SPS-based resin contained in the first layer or the preferred material, particle size, blending amount, and the like of the spherical filler are also the same as in the first embodiment. Here, the preferable particle size of the spherical filler is relatively determined with respect to the thickness of the first layer in the same way as the thickness of the single layer film in the first embodiment is relatively determined.

The resin forming the second layer 12 is not particularly limited, and can be selected from SPS resins, polyolefin resins such as polyethylene and polypropylene, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. Choose those with the desired characteristics to use. When the second layer is used to improve the mechanical properties of the multilayer film 10, the second layer preferably contains an SPS-based resin, and more preferably contains the same SPS-based resin as the first layer. The reason is that it is easy to manufacture by coextrusion as described later. When the second layer contains an SPS-based resin, the content of the spherical filler in the second layer is preferably less than that of the first layer, and the second layer is more preferably free of spherical filler. Thus, the second layer can be formed as a layer having better mechanical properties than the first layer.

Alternatively, the second layer 12 may be formed as an antistatic layer. The antistatic layer may be one prepared by blending an antistatic agent in a resin that becomes a matrix, or may be a layer containing a conductive resin. The second surface 16 is composed of an antistatic layer. Therefore, when the multilayer film 10 is used as a release film for resin molding, the first surface 15 is used toward the molded resin side, so that the surface of the resin molded product can be freely applied. With a glossy appearance, the second surface 16 is in contact with the mold at this time, so that the multilayer film 10 can be prevented from being charged.

In the example shown in FIG. 2, the multilayer film 20 is composed of three layers, including 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 in FIG. 2 is the same as the first layer in FIG. 1.

The resin forming the second layer 22 and the third layer 23 is not particularly limited, and one having desired characteristics can be selected and used. As an example, the second layer may be formed as a layer containing the same SPS-based resin as the first layer but not containing spherical fillers, and the third layer may be formed as an antistatic layer. As another example, the second layer is formed as a layer that contains the same SPS-based resin as the first layer but does not contain spherical fillers. If the third layer is constituted by the same layer as the first layer, the cross-section becomes a symmetrical structure. A multilayer film having the same roughened first surface and second surface can be obtained.

The layer structure of the multilayer film is not limited to that described above. The number of layers can be set to any number of layers above 2. Since the gloss 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.

The multilayer film of the present embodiment may be bonded via an adhesive layer after forming each layer as an independent film. For example, the polystyrene-based film of the first embodiment may be used as the first layer 11 and bonded to other films.

Alternatively, when the softening temperatures or viscosity curves of a plurality of resins are similar, these 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 to it contain the same SPS-based resin, the respective raw materials can be melted and kneaded to form a two-layered precursor film by co-extrusion, and then biaxially Stretching, thereby forming the first layer and the second layer at the same time.

Alternatively, a new layer may be formed by applying a resin material to the surface of another film. For example, the thickness of the antistatic layer is generally 0.1 μm or less, and it is difficult to form the thin layer in the form of a separate film. In this case, a conductive resin can be applied to the second surface of another single-layer or multilayer film and dried or cross-linked to form an antistatic layer.

If the film is multi-layered as in the present embodiment, the effect of increasing the degree of freedom of film design can be obtained. In a single-layer SPS-based film, if the surface roughness is increased, the tensile elongation tends to decrease. In contrast, in a multilayer film, by realizing required mechanical properties and the like with layers other than the first layer, the composition and the like of the first layer can be adjusted so as to optimize surface irregularities and texture. [Example]

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

The film of the example was produced as described below. As the SPS-based resin, syndiotactic polystyrene (SPS) resin (manufactured by Idemitsu Kosan Co., Ltd., XAREC 142ZE (glass transition temperature 95°C, melting point 247°C)) was used. A predetermined spherical filler was blended in the SPS at a predetermined ratio and kneaded, and then melt-extruded at 290°C using an extruder equipped with a T-die at the tip, and then cooled to obtain a precursor film. The precursor film was simultaneously biaxially stretched at a predetermined magnification at 110°C and a stretching speed of about 500%/min. After stretching, heat-fixed at 210°C with a relaxation ratio of 0.95 times in the longitudinal direction (MD) and 0.95 times in the transverse direction (TD) to obtain a biaxially stretched SPS system with a thickness of about 50 μm. membrane.

Regarding the film of Comparative Example 1, the SPS-based film was produced by the same method as in the examples without preparing a spherical filler. Regarding the film of Comparative Example 2, a spherical filler was blended in SPS, and an SPS-based film with a thickness of 50 μm that was not stretched was produced by melt and extrusion. Regarding the film of Comparative Example 3, an SPS-based film was produced in the same manner as in the examples.

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

The types, product numbers, and manufacturing companies of the spherical fillers shown by the symbols in Table 1 are as follows. ×F5: Silicon dioxide, FB-5SDC, Denka Co., Ltd. ×F7: Silicon dioxide, FB-7SDC, Denka Co., Ltd. ×H: Silicon dioxide, HS-207, Nippon Steel Materials Co., Ltd.×FE: Silicon dioxide, FEB25A-SQ, Admatechs Co., Ltd.×K: Silicon dioxide, KSE-2045, Kinseimatec Co., Ltd.×N : Silica, NP-100, AGCSI Technology (Tech) Co., Ltd.×S: Aluminosilicate, Hilton (Shilton) JC-50, and any spherical filler of Mizusawa Chemical Industry Co., Ltd. are amorphous. In addition, spherical fillers "F5", "F7", "H", "FE", and "K" are fused silica, and "N" is made by sintering spherical silica gel and making it nonporous.

The gloss in Table 1 is the 60-degree specular gloss and Gs (60°) specified in JISZ8741: 1997, using a gloss meter (Unigross 60, Konicaminolta Co., Ltd.) To determine. The surface roughness (Ra) is the arithmetic average roughness Ra specified in JIS B0601: 1994, and is measured using a surface roughness tester (Handy Surf, Tokyo Precision Co., Ltd.). The tensile elongation is measured by the method specified in JIS K7127: 1999, with the test piece type 2, the test speed is 200 mm/min, and the nominal tensile failure strain is obtained from the stress/strain curve obtained.

※調配量是相對於間規聚苯乙烯100重量份[Table 1]

※The blending amount is relative to 100 parts by weight of syndiotactic polystyrene

Comparing Comparative Example 1 with Examples 1 to 10, it is found that the film of the example has low gloss, large surface roughness (Ra), and roughened film surface. In addition, in the films of the examples, it was confirmed visually that the matt feeling was imparted. On the other hand, it was found that in the films of Examples 1 to 10, the tensile elongation of the film was lower than that of Comparative Example 1. However, in any of the examples, it was maintained at 15% or more. The resulting decrease in mechanical properties is suppressed to a practically sufficient range.

Comparing Comparative Example 2 with Example 6, in Comparative Example 2, which is not stretched, the gloss is low and the surface roughness (Ra) is large, but the tensile elongation is small. In Example 6 biaxially stretched, the gloss became lower, the surface roughness (Ra) became larger, and practically sufficient tensile elongation was obtained.

Comparing Comparative Example 3 with Examples 1 to 10, in Comparative Example 3 using fused silica with a large particle size, a surface roughness (Ra) greater than that of the Examples was obtained, but the tensile elongation was small. The reason for this is considered to be that the fused silica of Comparative Example 3 contained particles having a maximum particle size of 67 μm with respect to the film thickness of 50 μm, and therefore the film was broken under a smaller elongation.

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

The composition of the first layer was the same as that of Example 8. In the second layer, the spherical filler is used without blending the spherical filler in the same SPS as the first layer. The raw materials of the first layer and the second layer were kneaded separately, and melted and co-extruded at 290° C. using a two-layer molding extruder, and then cooled to obtain a two-layer precursor film. The two-layer precursor film was simultaneously biaxially stretched and thermally fixed under the same conditions as in Example 1 to Example 10, thereby obtaining the simultaneous biaxially stretched SPS-based two-layer film of Example 11 and Example 12.

Table 2 shows the production conditions, thickness, gloss and surface roughness (Ra) of the first surface of the two-layer film of Example 11 and Example 12, and tensile elongation.

※調配量是相對於間規聚苯乙烯100重量份[Table 2]

※The blending amount is relative to 100 parts by weight of syndiotactic polystyrene

According to Table 2, it is known that Example 11 and Example 12 have the same gloss and surface roughness (Ra) as the first surface of Example 8, and have a tensile elongation greater than that of Example 8. In addition, in the measurement of the tensile elongation of Example 11 and Example 12, the first layer did not break until the two-layer film broke.

The present invention is not limited to the above-mentioned embodiments or examples, and various modifications can be made within the scope of its technical idea. [Industrial availability]

The roughened polystyrene-based film and multilayer film of the present invention are particularly useful as a release film during molding of a printed circuit board made of epoxy resin, especially a release film (transfer film) having a transfer function. The use is not limited to this. In addition to the use as a release film, it is also useful for various applications that require a rough surface. In addition, when used as a release film, the type of plastic constituting the material to be molded is not particularly limited. For example, it can be used for epoxy resin, phenol resin, melamine resin, urea resin, alkyd resin, and polyimide resin. , Polyester resin, polyurethane resin, acrylic resin, etc. are being molded.

10、20‧‧‧Multilayer film 11‧‧‧The first layer 12,22‧‧‧The second layer 23‧‧‧The third layer 15‧‧‧The first surface 16,26‧‧‧The second surface

Fig. 1 is an example of a cross-sectional configuration diagram of a multilayer film according to a second embodiment of the present invention. Fig. 2 is another example of the cross-sectional configuration diagram of the multilayer film according to the second embodiment of the present invention.

10‧‧‧Multilayer film

11‧‧‧Level 1

12‧‧‧Level 2

15‧‧‧Surface 1

16‧‧‧Second surface

Claims (7)

A polystyrene film, characterized in that it contains syndiotactic polystyrene resin and spherical fillers, biaxially aligned, gloss is less than 30%, surface roughness Ra is 0.8μm or more, and tensile elongation is 15% or more, and relative to 100 parts by weight of the resin component, the blending amount of the spherical filler is 5 parts by weight or more and 20 parts by weight or less. The polystyrene-based film as described in item 1 of the scope of patent application, wherein the spherical filler is amorphous silica. The polystyrene-based film as described in item 2 of the scope of patent application, wherein the spherical filler is fused silica. The polystyrene-based film according to any one of items 1 to 3 in the scope of the patent application, wherein the maximum diameter of the spherical filler is less than the thickness of the polystyrene-based film, and the median diameter d50 It is 6% or more of the thickness of the polystyrene-based film. A multilayer film, comprising: a first layer, constituting a first surface with a gloss of 30% or less and a surface roughness Ra of 0.8 μm or more, containing syndiotactic polystyrene resin and spherical fillers, and biaxially aligned; and At least one resin layer is provided on the side of the first layer opposite to the first surface, and when the tensile elongation is 15% or more and the tensile strain is less than 15%, the first The layer does not break. The multi-layer film according to item 5 of the scope of patent application, wherein the resin layer adjacent to the first layer contains the same syndiotactic polystyrene resin as the first layer, and the content of the spherical filler is less than The first layer may not contain spherical fillers. The multilayer film as described in item 5 or item 6 of the scope of patent application, wherein the second surface on the side opposite to the first surface is composed of an antistatic layer.

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