JP2008094915A - Styrene resin composition and optical screen sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a styrene resin composition that can be manufactured by a simple operation, exhibits high optical transparency and a low water absorption and has excellent mechanical strengths, and an optical screen sheet that exhibits high optical transparency and a low water absorption and has excellent mechanical strengths. <P>SOLUTION: The styrene resin composition is obtained by melt-kneading a copolymer (A), comprising 75-100 wt.% of a styrene monomer unit and 0-25 wt.% of a (meth)acrylate ester monomer unit, and a rubbery polymer (B). The styrene resin composition is caused to have a flexural modulus of at least 1,800 MPa, an unnotched Charpy impact strength of at least 12 kJ/m<SP>2</SP>and a saturated water absorption ratio of at most 0.4% at a temperature of 60°C and a relative humidity of 90%. The optical screen sheet is manufactured by using the styrene resin composition as a substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a styrenic resin composition and an optical screen sheet using the same, and more particularly to an optical screen sheet suitably used as a screen material for projection televisions and the like.

  Conventionally, as a transmissive screen structure of a projection television, for example, a structure in which a Fresnel lens sheet and a lenticular lens sheet are superposed, a structure in which a front panel for protecting the lens sheet having the superposed structure is further mounted, etc. Are known.

  Furthermore, recently, as the pitch of lenticular lenses has become finer, the number of cases in which film-like lenticular lenses (hereinafter referred to as film wrench) are used is increasing. In this case, a sheet for supporting the film wrench is used. (Hereinafter, a film wrench support plate) is usually used.

  The lens sheets, the front panel, and the film wrench support plate described above are required to have excellent light transmittance because of the necessity of transmitting a large amount of light. In addition, excellent impact resistance is required because of the necessity of suppressing breakage during production and transportation.

As a thing excellent in the above-mentioned light transmittance and impact resistance, for example, in Patent Document 1, a monomer mixture composed of an aromatic vinyl monomer and a (meth) acrylic acid ester monomer, A resin-made impact-resistant Fresnel lens obtained by polymerizing a styrene-diene copolymer dissolved therein is disclosed.
Japanese Patent Laid-Open No. 5-341101

  However, since the Fresnel lens described in Patent Document 1 has a high water absorption rate, there is a problem that deformation such as warping or deflection occurs due to water absorption from the atmosphere during use, storage, or transportation.

  In addition, in order to obtain the Fresnel lens, a monomer mixture in which a styrene-diene copolymer is dissolved is polymerized, and the monomer mixture is polymerized in a state where the copolymer is uniformly dispersed. Control to make it difficult.

  An object of the present invention is to provide a styrene-based resin composition that can be produced by a simple operation, has high light transmittance and low water absorption, and has excellent mechanical strength.

  Another object of the present invention is to provide an optical screen sheet having high light transmittance and low water absorption, and having excellent mechanical strength.

In order to achieve the above object, the styrene resin composition of the present invention comprises 75 to 100% by weight of a styrene monomer unit and 0 to 25% by weight of a (meth) acrylate monomer unit. A styrenic resin composition obtained by mixing a copolymer (A) and a rubbery polymer (B), having a flexural modulus of 1800 MPa or more measured based on JIS K 7171 (1994) The Charpy impact strength of the unnotched specimen measured based on JIS K 7111 (1996) is 12 kJ / m ² or more, and the saturated water absorption at a temperature of 60 ° C. and a relative humidity of 90% is 0.4. % Or less.

  In the styrene resin composition of the present invention, it is preferable that the rubber-like polymer (B) includes a styrene monomer unit and a diene monomer unit.

  In the styrene resin composition of the present invention, it is preferable that the rubber-like polymer (B) is a block copolymer.

  The styrene resin composition of the present invention is preferably obtained by melt-kneading the copolymer (A) and the rubbery polymer (B).

  Furthermore, the sheet for an optical screen of the present invention is characterized by using the above-described styrene resin composition as a base material.

  The styrenic resin composition of the present invention does not require a complicated operation and can be prepared by a simple operation. Moreover, since it has a low water absorption rate and excellent mechanical strength, it is possible to suppress deformation such as warpage and deflection and occurrence of breakage such as cracks and chips. Furthermore, since it also has high light transmittance, it can be suitably used as a screen material for projection televisions, for example, a sheet for optical screens such as a Fresnel lens sheet, a lenticular lens sheet, a front panel, and a film wrench support plate.

  Moreover, since the sheet | seat for optical screens of this invention has high optical transparency and a low water absorption, and it has the outstanding mechanical strength, it can be used suitably as screen materials, such as a projection television.

  The styrene resin composition of the present invention comprises a copolymer (A) comprising 75 to 100% by weight of styrene monomer units and 0 to 25% by weight of (meth) acrylate monomer units, Containing a rubber-like polymer (B).

  The copolymer (A) can be obtained by copolymerizing a styrene monomer and a (meth) acrylic acid ester monomer as a copolymerization component.

  Examples of the styrenic monomer include nuclear alkyl substitution such as styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, p-ethylstyrene, and pt-butylstyrene. Examples include styrene, α-alkyl-substituted styrenes such as α-methylstyrene and α-methyl-p-methylstyrene, halogenated styrenes such as o-chlorostyrene and p-chlorostyrene, and preferably styrene. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester monomer means an acrylic acid ester monomer or a methacrylic acid ester monomer. Examples of such a monomer include methyl acrylate and methyl methacrylate. , Ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid 2 -Ethylhexyl, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, etc. are mentioned, Preferably, methyl methacrylate is mentioned. These may be used alone or in combination of two or more.

  In the copolymer (A), the (meth) acrylic acid ester monomer is an optional component and may be blended or may not be blended. When the (meth) acrylic acid ester monomer is blended, the blending amount is 0 to 33 parts by weight, preferably 5 to 30 parts by weight with respect to 100 parts by weight of the styrene monomer. It is. By setting the blending amount within this range, the content of the styrene monomer unit is 75 to 100% by weight in the total weight of the copolymer (A), and the (meth) acrylic acid ester monomer unit The content can be 0 to 25% by weight.

  In addition to the above-described components, an ethylenically unsaturated monomer copolymerizable with the above-described components can be contained as a copolymerization component.

  Examples of the ethylenically unsaturated monomer include (meth) acrylic acid ester monomers, acrylonitrile, methacrylonitrile, acrylamide, diacetone acrylamide, acrylic acid, methacrylic acid, maleic anhydride, phenylmaleimide, cyclohexylmaleimide Etc. These may be used alone or in combination of two or more.

  Then, the above-mentioned styrene monomer and (meth) acrylic acid ester monomer, and if necessary, an ethylenically unsaturated monomer as a copolymerization component are polymerized by a known polymerization method. A polymer (A) can be obtained. Examples of such a polymerization method include suspension polymerization, bulk polymerization, solution polymerization, emulsion polymerization, and the like, and preferably suspension polymerization.

  The copolymer (A) thus obtained contains 75 to 100% by weight of styrene monomer units and 0 to 25% by weight of (meth) acrylate monomer units. . By making the content rate of each monomer unit into the above-mentioned range, the water absorption rate of the styrene-based resin composition can be reduced.

  The copolymer (A) preferably contains 77 to 100% by weight of styrene monomer units and 0 to 23% by weight of (meth) acrylate monomer units. More preferably, it contains 77 to 95% by weight of styrene monomer units and 5 to 23% by weight of (meth) acrylic acid ester monomer units. When the content of the styrene monomer unit is 77 to 100% by weight and the content of the (meth) acrylic acid ester monomer unit is 0 to 23% by weight, the refraction of the rubbery polymer (B) to be described later Can be easily matched with rate.

  The rubbery polymer (B) is not particularly limited as long as it is a known rubber polymer that exhibits rubber-like properties at room temperature, and examples thereof include polybutadienes such as polybutadiene, hydrogenated or partially hydrogenated polybutadiene, and polyisoprene. , Polyisoprene such as hydrogenated or partially hydrogenated polyisoprene, styrene-butadiene random copolymer, hydrogenated or partially hydrogenated styrene-butadiene random copolymer, styrene-butadiene block copolymer Styrene-butadiene series, styrene-isoprene random copolymers, such as styrene-butadiene block copolymers that are coalesced, hydrogenated or partially hydrogenated, and styrene-isoprene random copolymers that are hydrogenated or partially hydrogenated , Styrene-isoprene block copolymer, hydrogenated or partially hydrogenated Styrene - styrene isoprene block copolymer - isoprene, ethylene - ethylene propylene copolymer - propylene and the like. These may be used alone or in combination of two or more. Moreover, a commercially available product may be used, or polymerization may be performed separately.

  The rubbery polymer (B) is preferably a rubbery polymer (B) containing a styrene monomer unit and a diene monomer unit. For example, the above-described styrene-butadiene is mentioned. And rubber-like polymers and styrene-isoprene rubber-like polymers. These may be used alone or in combination of two or more.

  The rubbery polymer (B) is more preferably a rubbery polymer (B) that is a block copolymer. Examples of such a rubbery polymer (B) include the above-described styrene-butadiene block copolymers, hydrogenated or partially hydrogenated styrene-butadiene block copolymers, and styrene-isoprene block copolymers. Examples thereof include a polymer, a hydrogenated or partially hydrogenated styrene-isoprene block copolymer, and particularly preferably a styrene-butadiene block copolymer. These may be used alone or in combination of two or more. If the rubber-like polymer (B) is a styrene-butadiene block copolymer, when the rubber-like polymer (B) is separately polymerized, the blending of the styrene monomer is suppressed while suppressing a decrease in rubber elasticity. Since the ratio can be adjusted in a wide range, the refractive index of the rubber-like polymer (B) described later can be adjusted in a wide range. As a result, the refractive index of the rubber-like polymer (B) can be easily matched with the refractive index of the copolymer (A).

  Examples of the styrene monomer used for constituting the styrene monomer unit of the styrene-butadiene block copolymer include the styrene monomers described above, preferably And styrene. These may be used alone or in combination of two or more. On the other hand, examples of the butadiene monomer used for constituting the butadiene monomer unit include butadiene, 2-methylbutadiene, 2,3-dimethylbutadiene, and preferably butadiene. . These may be used alone or in combination of two or more.

  The rubber-like polymer (B) may contain an ethylenically unsaturated monomer copolymerizable with the copolymer component of the rubber-like polymer (B) as a copolymer component.

  Examples of the ethylenically unsaturated monomer include the above-described ethylenically unsaturated monomers. These may be used independently and may be used together 2 or more types.

  When the rubbery polymer (B) is separately polymerized, the above-mentioned rubbery polymer (B) polymerization components (for example, styrene monomer, diene monomer, etc.) and, if necessary, ethylene A rubbery polymer (B) can be obtained by polymerizing a polymerizable unsaturated monomer as a copolymerization component by a known polymerization method. Examples of such a polymerization method include suspension polymerization, bulk polymerization, solution polymerization, and emulsion polymerization.

  The rubbery polymer (B) thus obtained is preferably a polymer polymerized by solution polymerization. These polymers can be used in combination of two or more. In that case, it is preferable to increase the ratio of the polymer polymerized by solution polymerization. If the ratio of the polymer polymerized by solution polymerization is increased, the water absorption of the styrene-based resin composition can be reduced, and wet heat durability and light resistance can be improved.

  Moreover, it is preferable that the refractive index of a rubber-like polymer (B) is substantially equivalent to the refractive index of a copolymer (A). If the refractive indexes are substantially equal, light can be prevented from scattering inside the styrene resin composition.

  And a styrene resin composition is obtained by mixing the above-mentioned copolymer (A) and rubber-like polymer (B) mechanically.

  The blending amount of the rubbery polymer (B) varies depending on the type of the rubbery polymer (B) to be used. For example, the total amount of the copolymer (A) and the rubbery polymer (B) is 100 parts by weight. On the other hand, it is 80 parts by weight or less, preferably 70 parts by weight or less, usually 5 parts by weight or more. If the blending amount exceeds 80 parts by weight, the rigidity (for example, the flexural modulus) of the styrene resin composition is lowered, and when processed into a sheet for an optical screen or the like, there is a case where bending tends to occur. On the other hand, if it is less than 5 parts by weight, impact resistance (for example, Charpy impact strength of a notched test piece) is lowered, and when processed into a sheet for an optical screen or the like, cracks and chips may easily occur. is there.

  In addition to the above-described components, known additives such as heat stabilizers, antioxidants, light stabilizers, ultraviolet absorbers, colorants, plasticizers, mold release agents, and lubricants are mixed in an appropriate amount if necessary. can do. These may be used alone or in combination of two or more. In addition, you may mix | blend these previously as a copolymerization component of a copolymer (A) and a rubber-like polymer (B).

  The mixing method is not particularly limited as long as the copolymer (A), the rubbery polymer (B), and, if necessary, the above-described additives can be mixed uniformly. After dry blending with a tumbler or the like, for example, melt kneading is performed using a known melt kneading apparatus such as a single screw extruder, a twin screw extruder, an open roll mill, a Banbury mixer, or a kneader. The resin temperature at the time of melt kneading is, for example, 160 to 270 ° C. In the case of mechanical mixing such as melt kneading, the respective components can be mixed by a simple operation, and the mixing ratio can be easily set and can be mixed uniformly.

  The bending elastic modulus of the styrenic resin composition thus obtained is 1800 MPa or more, preferably 2000 to 3500 MPa, measured based on JIS K 7171 (1994). By making the flexural modulus 1800 MPa or more, for example, when a sheet for an optical screen is produced using a styrene resin composition as a base material, for example, when it is installed on a projection television, when a sheet is handled, etc. Can be suppressed, and the thickness of the sheet can be reduced.

Moreover, the Charpy impact strength of the notched test piece measured based on JIS K 7111 (1996) of the styrene-based resin composition is 12 kJ / m ² or more. By setting the Charpy impact strength of the notched test piece to 12 kJ / m ² or more, for example, it is possible to prevent the sheet from being cracked or chipped during processing (for example, during sheet handling). The thickness of the sheet can be reduced. Moreover, it is preferable that the Charpy impact strength of a test piece without a notch is 15-50 kJ / m < ² >. If it is the range of 15-50 kJ / m < ² >, since it is not necessary to make content of a rubber-like polymer (B) excessive, the fall of a bending elastic modulus can be suppressed.

  Furthermore, the saturated water absorption of the styrene resin composition at a temperature of 60 ° C. and a relative humidity of 90% is 0.4% or less, preferably 0.3% or less. By setting the saturated water absorption rate to 0.4% or less under the above conditions, deformation such as warpage and deflection caused by water absorption can be suppressed, and dimensional stability can be improved.

  Such a saturated water absorption is obtained using the following formula, for example, where the weight of the dry styrene resin composition is W1 and the weight of the saturated water absorption styrene resin composition is W2.

Saturated water absorption (%) = 100 × (W2−W1) / W1
And the sheet | seat for optical screens of this invention is obtained by using the styrene resin composition obtained by the above-mentioned method as a base material.

  Examples of the optical screen sheet include an optical screen sheet used for a transmission screen of a projection television. More specifically, examples include a lens sheet original plate, a film wrench support plate, a Fresnel lens sheet, a lenticular lens sheet, and a front panel.

  When producing a Fresnel lens sheet, for example, it may be performed by cast molding, or a so-called lens sheet original plate obtained by cast molding, extrusion molding, or the like may be press-molded to give a Fresnel lens shape. Further, an ultraviolet curable resin may be cured on the surface of the sheet original plate as the original plate so that the Fresnel lens shape is formed.

  The sheet original plate used as the Fresnel lens sheet original plate preferably has a light transmittance of 50% or more at 360 nm. Recently, as described above from the viewpoint of cost and productivity, Fresnel lens molding using an ultraviolet curable resin has been mainly performed, but the light transmittance at 360 nm of the sheet original plate is less than 50%. In some cases, the ultraviolet curable resin for molding the Fresnel lens cannot be sufficiently cured.

  Moreover, when manufacturing a lenticular lens sheet, you may carry out by extrusion molding, for example, and you may carry out by casting. Further, a lenticular lens shape may be imparted by press-molding on the surface of the sheet original plate to be the original plate.

  The film wrench support plate is a plate for supporting a lenticular lens formed in a film shape, and can be obtained by molding by a method such as cast molding, extrusion molding or press molding. A lenticular lens can be obtained by, for example, bonding a lenticular lens-shaped ultraviolet curable resin film to the surface of the obtained film wrench support plate.

  The front panel is a panel for protecting a lens sheet constituting a transmission screen of a projection television, for example, and is obtained, for example, by directly casting, extruding, or pressing a styrene resin composition. Can do. Furthermore, if the obtained front panel is subjected to, for example, a hard coating process, a low reflection coating process, or the like, a front panel that is less likely to be scratched and can reduce reflection can be obtained.

  Moreover, when obtaining the sheet | seat for optical screens by an above-described method, in order to improve light diffusibility, an inorganic type fine particle and the bridge | crosslinking organic type fine particle can be added with a suitable compounding quantity as needed. The fine particles preferably have an average particle size of 1 μm to 40 μm.

  The optical screen sheet of the present invention thus obtained has a thickness of preferably 0.5 mm to 6 mm, and more preferably 0.5 mm to 4 mm, in order to reduce costs.

  Next, one embodiment of the optical screen sheet of the present invention will be described with reference to the drawings.

  FIG. 1 is a side sectional view showing an outline of a projection television. FIG. 2 is an enlarged view of the screen of the projection television shown in FIG. In these drawings, the left side of the drawing is the front (front) side, and the right side is the back (back) side.

  In FIG. 1, the projection television 1 includes a housing 2. A projection device 3 and a mirror 4 are installed inside the housing 2, and a screen 5 is installed on the front surface of the housing 2. That is, the projection television 1 displays the image on the front surface of the screen 5 by reflecting the light projected from the projection device 3 by the mirror 4 and projecting the image from the back surface of the screen 5 inside the housing 2. This is a so-called rear projection type projection television.

  The screen 5 will be described more specifically with reference to FIG. 2. The screen 5 is, in order from the back side, the Fresnel lens sheet 6 (more specifically, the Fresnel lens sheet original plate 7 and the Fresnel lens 8), and the lenticular. The lens sheet 9 and the front panel 10 are provided, and these are configured by a laminated structure that is close to each other so that the surfaces face each other. By making the structure of the screen 5 a laminated structure, the light reflected from the mirror 4 can be efficiently transmitted in the order of the Fresnel lens sheet 6, the lenticular lens sheet 9, and the front panel 10 to display an image.

  The optical screen sheet of the present invention can be used as at least one of the Fresnel lens sheet 6, the lenticular lens sheet 9, and the front panel 10 in the screen 5.

  In the above-described laminated structure, when each layer is deformed (for example, warping, deflection, etc.), the displayed image quality may be reduced due to this, but like the optical screen sheet of the present invention, If a sheet having excellent mechanical strength (for example, impact resistance, flexural modulus, etc.) and low water absorption is used, it can withstand impacts and changes in environmental conditions (for example, high humidity, etc.). Therefore, deformation such as warpage and deflection of each layer can be suppressed, and cracks and chips generated during processing can also be suppressed.

  Furthermore, since the optical screen sheet of the present invention is also excellent in light transmittance, the light reflected from the mirror 4 can be transmitted efficiently. As a result, it is possible to provide a projection television that can display an image more clearly.

  In the above description, the optical screen sheet of the present invention can be used for the Fresnel lens sheet 6. However, for example, the part of the Fresnel lens 8 can be formed of an ultraviolet curable resin.

Next, although this invention is demonstrated based on an Example and a comparative example, this invention is not limited by the following Example.
Example 1 and Comparative Examples 1-2
In the blending amounts shown in Table 1 below, styrene-methyl methacrylate copolymer (copolymer (A)) [MM20 manufactured by Nippon A & L Co., Ltd., weight ratio: styrene / methyl methacrylate = 80/20] and styrene- A butadiene block copolymer (rubber-like polymer (B)) [K Resin KR01 containing 25% by weight of butadiene manufactured by Chevron Phillips Chemical Co., Ltd.] is mixed and extruded using a 40 mmφ extruder (resin temperature of about 200 ° C.). Thus, pellets of the styrene resin composition were obtained. The obtained pellets were pressed by a hot press (hot plate temperature of about 200 ° C.) to obtain styrene resin sheets having a thickness of 1 mm and 2 mm.
Comparative Example 3
Styrene-butadiene random copolymer (rubber-like polymer (B)) [Toughden L208A manufactured by Nippon Elastomer Co., Ltd. Weight ratio: Styrene / Butadiene = 25/75] 6.7 parts by weight of styrene, 40.1 parts by weight , And 53.2 parts by weight of methyl methacrylate together with lauroyl peroxide and benzoyl peroxide (radical polymerization initiator), and using a two-stage stirring type continuous reaction apparatus, the mixture is held at 150 ° C. for 225 seconds. Partial polymerization was performed to obtain a partial polymer.

  The obtained partial polymer was transferred to another polymerization tank, and further to t-butylperoxy-2-ethylhexanoate (radical polymerization initiator), polymethacrylic acid and hydroxypropylcellulose (suspension). Stabilizer) and water were added, and suspension polymerization was carried out with stirring to complete the polymerization and obtain a slurry of a styrene resin composition. By washing and filtering the obtained slurry, a styrene resin composition in which a styrene-butadiene random copolymer was dispersed was obtained.

The obtained styrene-based resin composition is processed at a resin temperature of about 250 ° C. using a sheeting apparatus equipped with a 40 mmφ extruder, a T die, and a vertical three polishing roll, thereby obtaining a thickness of 1 mm. And the styrene resin sheet of 2 mm was obtained.
Evaluation Experiment The styrenic resin sheets obtained in each Example and each Comparative Example were evaluated by the following method. The results are shown in Table 1.
(A) Charpy impact strength of test piece without notch A test piece was cut out from a styrene resin sheet having a thickness of 2 mm and measured based on JIS K 7111 (1996).
(B) Flexural modulus A test piece was cut out from a styrene resin sheet having a thickness of 2 mm and measured based on JIS K 7171 (1994).
(C) Saturated water absorption rate A test piece of 3 cm × 5 cm was cut out from a styrene resin sheet having a thickness of 2 mm, vacuum-dried at 80 ° C. overnight, and the weight was measured. This weight was defined as the dry test piece weight (W1). Next, the test piece was placed in a constant temperature and humidity chamber adjusted to a temperature of 60 ° C. and a relative humidity of 90%, and left until the weight increase stopped. The weight at this time was defined as a water saturation test piece weight (W2). Subsequently, saturated water absorption (%) was calculated | required from the dry test piece weight (W1) and the water saturation test piece weight (W2) using the following formula.

Saturated water absorption (%) = 100 × (W2−W1) / W1
(D) Light transmittance (%)
A test piece of 4 cm × 6 cm was cut out from a styrene resin sheet having a thickness of 2 mm, and the light transmittance at 360 nm was measured using a self-recording spectrophotometer (U4000 manufactured by Hitachi, Ltd.).
(E) Warpage A test piece of 20 cm × 30 cm was cut out from a styrene resin sheet having a thickness of 2 mm, and an aluminum foil was attached to one side with an adhesive. This was placed in a thermo-hygrostat adjusted to a temperature of 60 ° C. and a relative humidity of 90% and left for 24 hours. After leaving, the degree of sheet warpage was determined by visual inspection. Note that the symbols shown in Table 1 represent the criteria that ○: warpage is small and x: warpage is large.
(F) Deflection A 20 cm × 30 cm test piece was cut out from a styrene resin sheet having a thickness of 1 mm, the 20 cm side was vertically set as the bottom, the bottom was fixed, and the degree of deflection was determined by visual inspection. . The symbols shown in Table 1 represent the criteria that ◎: deflection is very small, ◯: deflection is small, ×: deflection is large.
(G) Crack and chipping From a styrene resin sheet having a thickness of 1 mm, a test piece of 20 cm × 30 cm was cut by sawing, and the degree of cracking and chipping was determined by visually checking the state of the cross section. . In addition, the symbol shown in Table 1 represents the criteria that ○: no cracks and chips, x: many cracks and chips.

It is a sectional side view which shows the outline of a projection television. It is an enlarged view of the screen of the projection television of FIG.

Explanation of symbols

5 Screen 6 Fresnel lens sheet 9 Lenticular lens sheet 10 Front panel

Claims (5)

A copolymer (A) comprising 75 to 100% by weight of a styrene monomer unit and 0 to 25% by weight of a (meth) acrylate monomer unit;
A styrenic resin composition obtained by mixing a rubbery polymer (B),
The flexural modulus measured based on JIS K 7171 (1994) is 1800 MPa or more,
The Charpy impact strength of the test piece without notch measured based on JIS K 7111 (1996) is 12 kJ / m ² or more,
A styrene-based resin composition having a saturated water absorption rate of 0.4% or less at a temperature of 60 ° C. and a relative humidity of 90%.   The styrene resin composition according to claim 1, wherein the rubber-like polymer (B) contains a styrene monomer unit and a diene monomer unit.   The styrenic resin composition according to claim 1 or 2, wherein the rubber-like polymer (B) is a block copolymer.   The styrenic resin composition according to any one of claims 1 to 3, which is obtained by melt-kneading the copolymer (A) and the rubbery polymer (B).   An optical screen sheet comprising the styrene-based resin composition according to claim 1 as a base material.

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