JP6242602B2 - Styrene resin composition, styrene resin film, styrene laminate sheet and molded article - Google Patents

Description

  The present invention relates to a styrene resin composition, a styrene resin film, a styrene laminate sheet, and a molded body thereof.

  Conventionally, as a polystyrene-based laminated sheet for molding, a high-impact polystyrene (hereinafter referred to as “HIPS”) is used as a laminated sheet of a polystyrene film and an expanded polystyrene (hereinafter referred to as “PSP”) sheet, or an intermediate layer between the PSP sheet and the polystyrene film. And a laminated sheet provided with an adhesive resin layer is known.

  Since a polystyrene film generally has a brittle property, in order to cover the brittleness, it is usually used as a stretched film that has been stretched and oriented. The higher the orientation of the stretched film, the better the transparency, gloss, strength and printability. On the other hand, stretched film tends to have a small film elongation at the molding temperature, and when it is made into a laminated sheet, even if a simple shallow-drawn product can be produced, a deep-drawn product will cause film breakage during molding. In a square-shaped molded article having a corner having a relatively small R, the corner may be difficult to appear as in the mold (the mold determinism is poor).

  Films with a large amount of rubber components (HIPS, styrene-butadiene block copolymer, etc.) blended with polystyrene in order to improve film elongation during molding have toughness and large elongation at the molding temperature, so moldability It is known that a deep drawing can be performed in particular. However, since the blending of a large amount of rubber components impairs optical properties, a container formed by laminating the film tends to be difficult to finish into a beautiful printing container with insufficient transparency and gloss. In addition, since the rubber component is easily thermally oxidized and deteriorated, it decomposes to generate a gel and the like, so that the quality and appearance of the film may be deteriorated, the printability may be deteriorated, and the production equipment may be soiled.

  On the other hand, Patent Documents 1 and 2 disclose a resin composition in which a copolymer of a vinyl aromatic hydrocarbon and an aliphatic unsaturated carboxylic acid ester is mixed at a specific ratio as a method for improving film elongation at the time of molding. A polystyrene-based film using the product is disclosed. Moreover, as a method of improving the film elongation at the time of shaping | molding, in patent documents 3-5, the multi-branched polystyrene which has 4 mass% or more of styrene-type films using a multi-branched polystyrene and an acrylic ester unit was used. A styrenic film is disclosed.

Japanese Patent Publication No.2-16690 JP-A-9-123322 JP 2009-29949 A JP 2011-202064 A Japanese Patent No. 4423386

  However, in a container having a large deep drawing ratio which has become mainstream in recent years, the film elongation at the time of molding is still insufficient. Moreover, even if the film elongation can be improved, there are problems that the thickness unevenness of the film becomes large and the moldality is deteriorated.

  The present invention has been made in view of the above circumstances, and is formed using a styrenic resin composition capable of producing a molded article having a wide molding appropriate range and excellent mold determinism, and the styrenic resin composition. An object of the present invention is to provide a styrenic resin film, a styrenic laminated sheet, and a molded body.

The present invention relates to the following.
[1] A styrene resin composition containing a styrene resin containing linear polystyrene and hyperbranched polystyrene, wherein the mass ratio of linear polystyrene to hyperbranched polystyrene is 99.5: 0.5 to Styrenic resin composition having a content of monomer units in the range of 70:30 and based on the aliphatic unsaturated carboxylic acid ester monomer in the styrenic resin is 0.5 to 3.5% by mass. .
[2] The styrenic resin composition according to [1], wherein the aliphatic unsaturated carboxylic acid ester includes butyl acrylate and / or ethyl acrylate.
[3] The styrene resin composition according to [1] or [2], further containing at least one selected from the group consisting of high impact polystyrene and styrene-butadiene-styrene resin.
[4] A styrene resin film obtained by stretching the styrene resin composition according to any one of [1] to [3] in at least one direction.
[5] A styrene-based laminate comprising: a foamed polystyrene sheet having a thickness of 0.3 to 5.0 mm; and the styrene-based resin film according to [4] laminated on at least one surface of the foamed polystyrene sheet. Sheet.
[6] A molded body formed from the styrene-based laminated sheet according to [5].

  According to the present invention, a styrenic resin composition capable of producing a molded article having a wide molding appropriate range and excellent mold determination, a styrene resin film formed using the styrenic resin composition, and a styrenic resin Laminated sheets and molded bodies can be provided. Further, as a styrene film, a resin composition having a specific ratio of branching ratio (ratio of linear polystyrene and hyperbranched polystyrene) and containing an aliphatic unsaturated carboxylic acid ester unit at a specific ratio By using it, there is no quality deterioration due to gel, etc., and it is possible to obtain a printing film with excellent transparency, gloss, rigidity, and small thickness unevenness. It is possible to produce a molded article that is free from cutting and has excellent mold determinism.

It is a chromatograph of the styrene resin used in Example 1 measured by GPC-MALS method. It is a chromatograph of the styrenic resin used in comparative example 1 measured by GPC-MALS method. It is the graph which plotted the rotation radius with respect to the absolute molecular weight of the styrene resin measured by GPC-MALS method. It is a top view of the metal mold | die for a moldability evaluation. It is sectional drawing of the metal mold | die for a moldability evaluation. It is sectional drawing of the metal mold | die for a moldability evaluation. It is a cell division diagram which shows a moldability range. It is a perspective view of the molded object shape | molded with the metal mold | die for a moldability evaluation.

<Styrenic resin composition>
The styrene resin composition of this embodiment contains a styrene resin containing linear polystyrene and hyperbranched polystyrene, and the mass ratio of linear polystyrene to hyperbranched polystyrene is 99.5: 0.5 to It is in the range of 70:30, and the content of the monomer unit based on the aliphatic unsaturated carboxylic acid ester monomer in the styrene-based resin is 0.5 to 3.5% by mass. .

  The hyperbranched polystyrene contained in the styrene resin has a branched structure. As the branch structure, there are generally a random branch structure, a star structure, or a pom-pom structure. As a method for introducing branching into the styrene-based resin, there are a method using an organic peroxide, a method using a polyfunctional monomer, a method using ionic crosslinking, and a method using a multibranched macromonomer. Of these, styrenic resins using a hyperbranched macromonomer and having a molecular structure in which a star-shaped structure and a pompon type coexist are used for gelation suppression, film extrudability, film-forming property, and secondary moldability. It is preferable from the viewpoint of (uniform elongation and thickness). Examples of such a styrene resin containing multi-branched polystyrene include DIC Corporation trade names “High Branch HP-100, High Branch HP-100F-1, High Branch HP-100F-2”.

  The mass ratio between the linear polystyrene and the hyperbranched polystyrene according to this embodiment can be calculated from the mass average molecular weight measured under the following conditions by the GPC-MALS method.

The mass average molecular weight was measured using high performance liquid chromatography (product name “HLC-8120GPC” manufactured by Tosoh Corporation), column: TSKgel GMH _HR- H (7.8 mm ID × 30 cm) × 2 (Tosoh Corporation) Manufactured), MALS detector (DAWN HELEOS, manufactured by Wyatt), MALS laser wavelength: 658 nm, solvent: THF, flow rate 1.0 mL / min, column temperature: 40 ° C., MALS temperature: room temperature.

  Analysis of the chromatograph measured by the GPC-MALS method is performed with the analysis software ASTRA of Wyatt, and the ratio of the linear polystyrene and the hyperbranched polystyrene is determined by separating the appearing peaks according to the following procedure. Can be sought.

  A specific example of the peak separation method will be described using a chromatograph measured by the GPC-MALS method of the styrene resin used in Example 1 and Comparative Example 1 described later. 1 is a chromatograph of the styrene resin used in Example 1 measured by GPC-MALS method, and FIG. 2 is a chromatograph of the styrene resin used in Comparative Example 1 measured by GPC-MALS method. It is a graph.

  In the chromatograph, the horizontal axis indicates the amount of solvent flow (retention time) from the start of measurement, and the vertical axis indicates the peak intensity. A component peak with a smaller amount of solvent has a higher molecular weight. 1 and 2, P1 represented by a broken line is a portion based on linear polystyrene which is a low molecular weight component in the styrene resin, and P2 obtained by subtracting P1 from the chromatograph is a multi-branch which is a high molecular weight component. It is a part based on polystyrene.

  As shown in FIG. 2, the ratio of P2 of the multi-branched polystyrene portion and P1 of the linear polystyrene portion is perpendicular to the horizontal axis drawn from the peak top of P2, and the area of the line-symmetric portion of P2 is multi-branched. The area of the remaining part obtained by subtracting this part from the whole can be obtained as the mass ratio of the linear polystyrene. As shown in FIG. 1, when there is no clear top peak, the mass ratio can be calculated assuming that the inflection point at the rise of the elution curve is the apex and the peak top of P2.

  The slope of the rotation radius (RM Radius) plotted against the absolute molecular weight (Molar Mass) of the styrene resin measured by the GPC-MALS method is an index of branching of the styrene resin. The radius of rotation refers to a weighted average value of the distance from the center of gravity of the polymer molecule. Since the turning radius of the branched polymer is smaller than that of the linear polymer having the same molecular weight, the smaller the slope of the plot, the more the branching tendency.

  FIG. 3 is a graph plotting the radius of rotation with respect to the absolute molecular weight of the styrenic resin used in Example 1 and Comparative Examples 1 and 2 described later. In the case of only linear polystyrene not containing a branch, the slope of the plot exceeds 0.50, and when the styrene resin contains multi-branched polystyrene, the slope of the plot shows a value of 0.50 or less. Therefore, if the slope of the plot is 0.50 or less, it becomes an indicator that the styrene-based resin contains branched polystyrene.

  In the styrenic resin according to this embodiment, the slope calculated from the above-described plot is preferably 0.44 to 0.50, and more preferably 0.45 to 0.50.

  The mass ratio of linear polystyrene to branched polystyrene in the styrene resin is in the range of 99.5: 0.5 to 70:30, and preferably in the range of 95: 5 to 75:25. When the mass ratio of the branched polystyrene is less than 0.5, the film is easily cut in the deep drawing process. On the other hand, if the mass ratio of the branched polystyrene exceeds 30, the thickness unevenness of the film becomes large in the step of forming the film, and the moldality in the deep drawing step and the uneven thickness of the molded product become worse. The cause of this has not been elucidated, but the present inventors speculate that because the branching ratio is too large, strain hardening is too strong and local melting unevenness may occur.

  When this mass ratio is in the range of 99.5: 0.5 to 70:30, it is easy to stretch and form a film, and the stability during stretch film formation is improved. , Film elongation can be achieved at the same time. Here, the stability at the time of stretching film formation means that there is no necking, the stretching start position is stable, and the thickness unevenness is small enough that there is no practical problem. Generally, R is 10% or less, preferably 3% or less, and more preferably 2% or less.

  The mass average molecular weight of the linear polystyrene (P1) in the styrene resin determined by the GPC-MALS method is preferably 200,000 to 4480,000, and the mass average molecular weight of the multi-branched polystyrene (P2) is 1,000,000. It is preferably ˜10 million.

  The styrene resin can be produced by copolymerizing a styrene monomer, a hyperbranched macromonomer, and an aliphatic unsaturated carboxylic acid ester. The styrene resin is obtained by copolymerizing a copolymer obtained by copolymerizing a styrene monomer and a hyperbranched macromonomer, and a styrene monomer and an aliphatic unsaturated carboxylic acid ester. A mixture with a copolymer may also be used. Furthermore, the styrene resin is a copolymer obtained by copolymerizing a styrene monomer and a hyperbranched macromonomer, and other monomers having monomer units based on an aliphatic unsaturated carboxylic acid ester monomer. A mixture with a copolymer may also be used. Styrenic resin may be used individually by 1 type, or 2 or more types may be mixed and used for it. The linear polystyrene and the hyperbranched polystyrene may also be a copolymer containing a monomer such as an unsaturated carboxylic acid ester in addition to the styrene monomer, similarly to the styrene resin described above. .

  As the styrene monomer, styrene or a derivative thereof can be used. Examples of the styrene derivative include alkyl-substituted styrene such as methylstyrene and α-methylstyrene, and halogen-substituted styrene such as bromostyrene and α-bromostyrene.

  As the multi-branched macromonomer, a monomer having a plurality of branches and having an aliphatic unsaturated bond copolymerizable with a styrene monomer can be used. The hyperbranched macromonomer can be obtained, for example, by a method disclosed in JP 2011-202064 A.

  As the multibranched macromonomer, for example, a macromonomer in which a (meth) acryl group is introduced into a dendrimer, a hyperbranched polymer, a multibranched polyether polyol, an active methylene group in one molecule, bromine, chlorine, methylsulfonyloxy group or An unreacted active methylene group or methine group remaining in the polycondensate using as a precursor a multi-branched self-condensation polycondensate obtained by nucleophilic substitution reaction of an AB2 type monomer having a tosyloxy group and the like A multi-branched macromonomer or the like obtained by introducing a polymerizable double bond by nucleophilic substitution reaction with chloromethylstyrene, bromomethylstyrene or the like can be suitably used.

  The mass average molecular weight of the hyperbranched macromonomer is not particularly limited, and is about 1000 to 15000. The mass average molecular weight of the hyperbranched macromonomer can be measured by the GPC-MALS method described above.

  Examples of the aliphatic unsaturated carboxylic acid ester include (meth) acrylic acid ester derivatives. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) Esters of (meth) acrylic acid such as butyl acrylate and alkyl alcohols having 1 to 12 carbon atoms, esters of (meth) acrylic acid and alkylene oxides, esters of (meth) acrylic acid and alicyclic alcohols And the like. At least one of these is selected. In addition, (meth) acryl means acryl or methacryl corresponding to this. Among these, butyl (meth) acrylate or ethyl (meth) acrylate is preferable, and butyl acrylate or ethyl acrylate is more preferable from the viewpoints of film thickness unevenness and deep drawability.

  The content of the aliphatic unsaturated carboxylic acid ester unit in the styrene-based resin is 0.5 to 3.5% by mass, preferably 0.6 to 3.3% by mass, and 0.9 to 2%. More preferably, it is 5 mass%. If it is less than 0.5% by mass, the deep drawability is insufficient, and if it is more than 3.5% by mass, the thickness unevenness of the film becomes large in the process of forming a film, or the mold in the deep drawing process The determinism becomes worse.

The content of the aliphatic unsaturated carboxylic acid ester unit can be quantified by measuring the styrene resin by nuclear magnetic resonance spectroscopy. For example, in the case of butyl acrylate, from the ratio of the integrated value of the peak of the benzene ring of 6.5 to 7.5 ppm of styrene and the peak of the terminal methyl group of 0.8 ppm of butyl acrylate in the ¹ H-NMR spectrum. Can be calculated.

  There is no restriction | limiting in particular as a manufacturing method of a styrene resin, You may copolymerize an aliphatic unsaturated carboxylic acid ester in the process of superposing | polymerizing a styrene monomer and a hyperbranched macromonomer. In addition, a polymer produced by polymerizing a styrene monomer and a hyperbranched macromonomer and a polymer produced using an aliphatic unsaturated carboxylic acid ester are mixed by dry blending or kneading to produce a styrene Resins can also be prepared.

  For the polymerization reaction, a known and commonly used styrene polymerization method can be used, and is not particularly limited, but bulk polymerization, suspension polymerization or solution polymerization is preferred. Thermal polymerization can be performed without using a polymerization initiator, but it is preferable to use a conventional radical polymerization initiator. Moreover, the usual thing used for manufacture of a normal polystyrene can be used for polymerization adjuvants, such as a suspending agent and an emulsifier required for superposition | polymerization.

  From the viewpoint that the target styrene resin can be efficiently produced by a one-step reaction, the production methods described in JP-A-2005-053939, JP-A-2011-202064 and the like can be employed. For example, a monomer mixture containing a styrene monomer, a hyperbranched macromonomer, and an aliphatic unsaturated carboxylic acid ester may be reacted using a solution polymerization method or a melt polymerization method (bulk polymerization method).

  When synthesizing a styrenic resin, the reaction can be carried out without adding an organic solvent, but a small amount of an organic solvent can be added to adjust the viscosity of the reaction product and control the molecular weight of the resulting polymer. .

Examples of the organic solvent include toluene, ethylbenzene, xylene, acetonitrile, benzene, chlorobenzene, dichlorobenzene, anisole, cyanobenzene, dimethylformamide, N, N-dimethylacetamide, methyl ethyl ketone, and the like.
Conventionally known organic peroxides and azo compounds can be used as the radical polymerization initiator. Examples of the organic peroxide include peroxydicarbonates, peroxyesters, peroxyketals, dialkyl peroxides, diacyl peroxides, hydroperoxides, and silyl peroxides. Examples of the azo compound include 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutylnitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2, 2'-azobis (2-methylbutyronitrile) and 2,2'-azobis [2- (hydroxymethyl) propionitrile]. These radical polymerization initiators can be used alone or in combination of two or more.

  In order to adjust the molecular weight of the styrene resin, a chain transfer agent may be added during the polymerization.

  The content of the styrene resin in the styrene resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, and 85% by mass based on the total mass of the styrene resin composition. It is still more preferable that it is above. When the content of the styrenic resin is less than 50%, the characteristics of the styrenic resin film in transparency, hardness, printability, etc. of the film may be impaired.

  Styrenic resin compositions have stability during stretch film formation, slipperiness of the film (if the film does not slip in the printing process or deep-drawing molding process, film runnability tends to be poor), deep drawing of the film In order to improve properties such as property, at least one selected from the group consisting of high impact polystyrene and styrene-butadiene-styrene resin can be blended.

  The blending amount when blending high impact polystyrene or styrene-butadiene-styrene resin is preferably 0.5 to 15% by mass, more preferably 1.0 to 10% by mass with respect to 100% by mass of the styrene resin. . When blended in an amount of 0.5% by mass or more, stretching stability and slipperiness are improved, and in the case of 15% by mass or less, the transparency, gloss, and stiffness of the film are maintained.

<Styrenic resin film>
A styrene resin film can be obtained by stretching the styrene resin composition in at least one direction.

  As a typical example of a method for producing a stretched film, a thermoplastic resin is melt-kneaded with a screw extruder or the like, formed into a sheet shape with a T die, and then uniaxially stretched by roll stretching or tenter stretching. Subsequently, a method of biaxial stretching by tenter stretching or a method of stretching by an inflation method can be mentioned. The draw ratio at this time is preferably 2 to 20 times and more preferably 5 to 10 times in at least one direction of the vertical and horizontal directions.

  The reason for stretching in at least one direction is to improve the flatness of the film (reducing uneven thickness, eliminating surface irregularities) and increasing the strength of the film. Can be improved. The stretched film is useful for preventing film breakage and film wrinkle prevention during laminating (smooth film does not wrinkle), and for printing, the finish (preventing ink misregistration and ink application unevenness) is improved. , It helps to improve productivity (stable film running, film breakage prevention).

  The thickness of the styrene resin film is preferably 8 to 80 μm. When the thickness of the film is less than 8 μm, it is too thin and often breaks during processing such as printing, laminating, and deep drawing.

  The styrenic resin film may be printed with characters or figures on one side or both sides. The printing method is not particularly limited, and for example, multicolor printing such as gravure printing or flexographic printing can be used.

<Styrene laminated sheet>
The styrene resin film of the present embodiment can be laminated on at least one surface of the expanded polystyrene sheet. The styrene-based laminated sheet of this embodiment includes a foamed polystyrene sheet and the styrene-based resin film laminated on at least one surface of the foamed polystyrene sheet.

  The thickness of the expanded polystyrene sheet is not particularly limited, and is about 0.3 to 5.0 mm.

  The method for producing the laminated sheet may be any method as long as it is a generally known laminating method by heating. Examples of the laminating method include a thermal laminating method in which pressure bonding is performed with a hot roll, an extrusion laminating method of PSP, an extrusion sand laminating method in which HIPS is melt-extruded between a sheet and a film and laminated.

<Molded body>
A molded body can be formed from the styrene-based laminated sheet. The styrene-based laminated sheet of the present embodiment is formed into a container having a desired shape and a desired size, a container with a lid, or a container lid by a thermoforming method for forming into a container shape or the like, for example, a vacuum forming method or a pressure forming method. Can do. Since a packaging container having a thin printed film layer can be obtained from the styrene-based laminated sheet, the cost of manufacturing the container can be reduced while contributing to the reduction of environmental load such as reduction of CO ₂ emission and resource saving. In addition, it is possible to manufacture a wide variety of containers without breaking the film even in a container having a large deep drawing ratio that has become mainstream in recent years.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention should not be limited to the scope of these examples.

(Synthesis example) Synthesis of multi-branched macromonomer To 25.3 g of ethoxylated pentaerythritol, 0.5 g of boron trifluoride diethyl ether complex is added and heated to 110 ° C., and 225 g of 3-ethyl-3-oxetanemethanol is added dropwise. Then, the reaction was carried out at 120 ° C. for 3 hours. Thereafter, the reaction solution was cooled to room temperature to obtain a multi-branched polyether polyol.

  A mixed liquid obtained by adding 25 g of the above multi-branched polyether polyol, 6.9 g of methacrylic acid, 75 g of toluene, 0.03 g of hydroquinone and 0.5 g of paratoluenesulfonic acid is heated while blowing 7% by volume of oxygen-containing nitrogen. The reaction was performed. After completion of the reaction, the mixture was cooled to room temperature, 18 g of acetic anhydride and 2.9 g of sulfamic acid were added, and the mixture was stirred at 60 ° C. for 10 hours. Thereafter, the reaction solution was cooled to room temperature, 0.01 g of methoquinone was added to the organic layer washed in this order with a 5% by mass sodium hydroxide aqueous solution, 1% by mass sulfuric acid aqueous solution and water, and 7% by volume oxygen-containing nitrogen was added under reduced pressure. While being introduced, the solvent was distilled off to obtain a multibranched macromonomer having a methacryloyl group and an acetyl group. The obtained hyperbranched macromonomer had a mass average molecular weight of 4200.

(Production of styrene resin)
Styrene resins PS-1 to 4 and 6 to 11 were produced by polymerizing a monomer mixture in which the blending ratio of styrene, the above multibranched macromonomer and butyl acrylate was changed by a solution polymerization method. PS-5 was prepared by kneading 25 parts by mass of PS-10 and 75 parts by mass of PS-11 using a biaxial extruder. The solution polymerization method was performed according to the method described in Example 1 of JP2011-202064.

(Mass ratio of linear polystyrene to hyperbranched polystyrene)
The mass average molecular weight of the styrene resin was measured by the GPC-MALS method, and the mass ratio of linear polystyrene to hyperbranched polystyrene was calculated.

(Content of aliphatic unsaturated carboxylic acid ester unit)
50 mg of a styrene resin was dissolved in 1 mL of d-chloroform, ¹ H-NMR and ¹³ C-NMR spectra were measured, and the content of aliphatic unsaturated carboxylic acid ester units was calculated. The number of integrations was ¹ H-NMR: 256 times and ¹³ C-NMR: 20000 times.

[Preparation of Styrenic Resin Composition]
0 to 15 parts by mass of high impact polystyrene (HIPS-1) is mixed with a blender with respect to 100 parts by mass of the styrene resin, and pellets of the styrene resin compositions of the examples shown in Table 1 and the comparative examples shown in Table 2. Was made. Further, using the prepared pellets, the Vicat softening temperature of the styrene-based resin composition was measured according to ASTM-D1525 under the conditions of a load of 1 kg and a heating rate of 2 ° C./min, and the MFR (melt flow rate) was measured according to ASTM- It was measured under G condition (200 ° C., 5 kg) of D1238.

[Production of styrene resin film]
Styrenic resin composition pellets were formed by the following inflation film formation method or tenter sequential biaxial stretching film formation method to obtain a styrene resin film. Tables 1 and 2 show the film formation conditions (resin temperature, draw ratio) and film thickness of each film.
Inflation film forming method: A tube extruded by a circular die extruder having a 60 mmφ screw with L / D = 45 is blown and cooled, and wound as a desired film.
Tenter Sequential Biaxial Stretch Film Formation Method: A parison extruded from a T-die with an extruder having a 65 mmφ screw with L / D = 32 is stretched with a roll-heated longitudinal stretcher, then stretched transversely with a tenter, and then cooled. To obtain a desired film.

<Evaluation>
(A) Uneven thickness of film Using a thickness meter (product name “Dial Thickness Gauge SM-1201” manufactured by Teclock Co., Ltd.), a film sample having a size of 1.0 m in the horizontal direction and 1.0 m in the vertical direction was cut out. And about three places of the center part, thickness was measured at intervals of 1 cm in each direction. (Difference between the thickest part and the thinnest part) / Average thickness was defined as uneven thickness (unit:%) and evaluated according to the following criteria.
◎: Less than 10% ○: 10% or more and less than 20% Δ: 20% or more and less than 50% ×: 50% or more

(B) Number of gels in the film The number of gels, decomposition products, and foreign matters having a size of 0.2 mmφ or more found on the deflecting plate was measured in a 0.5 m × 2.0 m film (n = 3).
◎: 0 to 15 ○: 16 to 30 Δ: 31 to 60 ×: 61 or more

(C) Printability Using a gravure roll printing machine (roll width 80 cm, roll diameter 10 cm, speed 80 m / min), a test film having a width of 64 cm is divided into three gravure roll plates (plate depth 38 μm, 22 μm, 6 μm, all) Three colors (175 lines / inch) were printed. As printing inks, gravure ink XGS-820 indigo 800, XGS-810 white 120, and XGS-820 black 1000 manufactured by Sakata Inx Co., Ltd. were used. The printability was evaluated for the following four items (ink jump, appearance appearance, misregistration, film runnability), and the following four items were evaluated comprehensively.
A: The ink jumping, the appearance appearance, the registration shift, and the film running property are all good and the printing state is very beautiful.
○: One item among ink jumping, appearance appearance, misregistration, and film runnability, although there are some defects, but there are no practical problems.
Δ: Two or more items among ink jump, appearance appearance, misregistration, and film runnability, and there are some defects, but there is no practical problem.
X: Ink jumping, appearance appearance, misregistration, and film runnability are poor and have practical problems.

[Production of styrene-based laminated sheet]
The film printed above was subjected to laminating and forming tests and evaluated. First, the laminate was subjected to single-sided thermal lamination with a 2.1 mm thick PSP (Pearl Package Co., Ltd. # 70, foaming density 0.11 g / mL, width 630 mm) to obtain a laminated sheet. The thermal lamination was performed by a thermal laminating machine equipped with a thermocompression roller (a dielectric heating roll having a roll surface temperature of 198 ° C., a diameter of 400 mm, a roll width of 1.3 m, and a roll speed of 10 m / min).

[Production of molded body]
About the said lamination sheet, vacuum forming was performed with the following method and the moldability was evaluated.

(D) Molding suitability range (area where film breakage, wrinkles and secondary foaming do not occur)
In a vacuum forming machine (sheet width 630 mm, heating zone 2 zone, far infrared heater radiant heating method), moldability evaluation molds (drawing ratios of 0.1, 0.2, 0. 3, 0.4, 0.5, 0.6, 0.7, each mold having an angle θ of 10, 20, and 30 degrees of the container body), and performing a vacuum forming test (without plug assist), The molded body shown in FIG. 8 was produced. 4 levels of molding temperature range (230, 240, 250, 260 ° C for extrusion sand laminating, 200, 210, 220, 230 ° C for thermal laminating and double-sided thermal laminating), molding time 5 seconds per zone The breadth of the range in which a molded container having a good mold specification in which film breakage, molding wrinkles, and secondary foaming of PSP were not observed when molding was performed was determined.

In the molding test, n = 4 shots were molded per condition, and the average value (width) was displayed. 5 is a cross-sectional view taken along the line AA ′ in the plan view of the mold for evaluating formability shown in FIG. 4, and FIG. 6 is a line cut along the line BB ′. The cross-sectional views are respectively shown. The drawing ratio is indicated by Lh / Lm shown in FIGS. 5 and 6, and the angle of the container body is indicated by θ. Moreover, FIG. 7 is explanatory drawing which shows a shaping | molding range. That is, when the relationship between the drawing ratio and the heater setting temperature is taken, it shows a range in which a molded container with a good mold can be obtained without film breakage, molding wrinkles and secondary foaming of PSP. This is represented by the number of sections 7, and the larger the number of square sections, the wider the molding range. The number of square sections is represented by a total of three types in which the container body angle θ is 10, 20, and 30 degrees.
(Double-circle): The number of divisions 50-60. Molding temperature, molding time and deep drawing are all the best.
A: Number of sections 40-49. Molding is good, but the molding range is moderate.
(Triangle | delta): The number of divisions 24-39. Molding aptitude range is slightly narrow and difficult to mold.
X: Number of compartments 0-23. Narrow aptitude range due to film breakage and secondary foaming.

(E) Deep drawability In the above-described molding test method, the maximum draw ratio of a good molded product obtained under optimum conditions (temperature, time) is expressed. The aperture ratio is a value calculated from the following equation from FIG.
Aperture ratio = mold depth (Lh) / mold long side length (Lm)
◎: 0.6 or more ○: 0.5
Δ: 0.4
X: 0.3 or less

(F) Mold Determinability This represents the degree of mold determination relative to the mold, and the particularly severe bottom portion of the container obtained in the above molding test was visually observed. For the target sample, the best molded product was selected and examined.
(Double-circle): It shape | molds according to the type | mold and the unevenness | corrugation of the metal mold | die surface is not transferred.
○: Molded almost as usual.
(Triangle | delta): It has become a sweet shaping | molding or the unevenness | corrugation on the metal mold | die surface is seen.
X: Not as usual.

(G) Uneven thickness of molded product The ratio of the maximum thickness of the film layer to the original thickness before molding at the corner portion by molding was expressed as a ratio. When this ratio is large, it indicates that the film stretches locally and the uneven thickness is large, and it is preferable that the whole stretch evenly.
◎: 0.31 or more ○: 0.26 or more and less than 0.31 Δ: More than 0.20 and less than 0.26 ×: 0.20 or less

(H) Film breakage of molded product The appearance of film breakage was expressed by appearance inspection of the container obtained in the above molding test. It is preferable that there is no or little film breakage. Temperature 4 level × drawing ratio 5 level = 20 indicates how many pieces of film are cut out.
◎: 0 ◯: 1 △: 2-5 ×: 6 or more (i) Appearance of the appearance of the molded container (transparency, good gloss)

In the above-described molding test, it is preferable that the molded container is clearly printed to observe from the outer surface of the film and that the transparency and gloss are excellent. This shows the same tendency as the transparency and gloss of the film, but some of them are molded to deteriorate the transparency and gloss. Printing was performed on the back side of the film, and observation was performed from the front side.
A: Both transparency and gloss are good, and the printed finish of the molded container is excellent.
○: Transparency and gloss are good.
Δ: Transparency is slightly good but not glossy.
X: Poor transparency and no gloss.

(J) Comprehensive evaluation of moldability The comprehensive judgment of the above nine items (a) to (i) is defined by the following criteria.
The determination results of (a) to (i) are as follows: ◎: 1 point, ◯: 2 points, Δ: 3 points, x: 4 points, and the sum is as follows.
A (very practically excellent level): 10 points or less. In each item, there is no Δ or X.
○ (Practical level): 11 to 13 points. And there is no x in each item.
Δ (a level causing no practical problem): 14 to 20 points. And there is no x in each item.
X (Practical problem level): 21 points or more.

  From Table 1, it is confirmed that the styrene resin compositions of Examples 1 to 13 are excellent in film formability, the produced styrene resin film has good printability, and the styrene laminated sheet is excellent in moldability. it can. In particular, in Examples 1, 2 and 5, the balance of film forming property, printability and moldability was very excellent.

  On the other hand, since Comparative Example 1 uses a styrene resin composition having a high branching ratio, the thickness unevenness of the film is large in the process of forming the film, and the mold determination and molding in the deep drawing process The uneven thickness of goods is also bad. Since the comparative example 2 uses the styrene resin composition with a small branching ratio, the film is easily cut in the deep drawing process and the deep drawing property is poor. Since Comparative Example 3 uses a styrene-based resin composition having a large number of aliphatic unsaturated carboxylic acid ester units, the thickness unevenness of the film is large in the process of forming a film, and the mold determinism in the deep drawing process And the uneven thickness of the molded product is also bad. Since the comparative example 4 uses the styrenic resin composition which does not contain an aliphatic unsaturated carboxylic acid ester unit, the film is easily cut in the deep drawing process, and the deep drawability is poor.

  DESCRIPTION OF SYMBOLS 1 ... Molded object, 10 ... 1 division of the square division showing the range where a moldability is favorable.

Claims (5)

A styrene resin composition comprising a styrene resin containing linear polystyrene and hyperbranched polystyrene, and at least one selected from the group consisting of high impact polystyrene and styrene-butadiene-styrene resin,
And the linear polystyrene, the weight ratio of the hyperbranched polystyrene 99.5: 0.5 to 71: 29 by weight,
The styrenic resin composition, wherein the content of monomer units based on the aliphatic unsaturated carboxylic acid ester monomer in the styrenic resin is 0.5 to 3.5% by mass.   The styrenic resin composition according to claim 1, wherein the aliphatic unsaturated carboxylic acid ester is butyl (meth) acrylate and / or ethyl (meth) acrylate.   A styrene resin film obtained by stretching the styrene resin composition according to claim 1 or 2 in at least one direction. An expanded polystyrene sheet;
The styrenic resin film according to claim 3 laminated on at least one surface of the expanded polystyrene sheet;
A styrene-based laminated sheet.   The molded object formed from the styrene-type laminated sheet of Claim 4.