JP2020100681A - Styrenic film, molde article, method for producing styrenic film - Google Patents

Abstract

To provide a styrenic film that has a wide molding condition width, an excellent moldability and excellent appearance.SOLUTION: The styrenic film of the present invention contains a styrenic resin composition (I) containing a rubber-like elastic material particle (B) as dispersed particle in a matrix phase (A), wherein the matrix phase (A) is a styrenic resin composition (II) in which the degree of branching is 0.70 to 0.94, the degree of gelation is 1.00 to 1.25, the content of the component having an absolute molecular weight of 1,000,000 to 5,000,000 measured using a multi angle light scattering (MALS) is 5.0 to 15.0%, and the ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) is 3.0 to 5.0, and the styrenic resin composition (I) contains 0.1 to 2.5 mass% of the rubber-like elastic material particle (B).SELECTED DRAWING: Figure 1

Description

The present invention relates to a styrene film, a molded product thereof, and a method for producing a styrene film.

A film containing a styrene-based resin composition is widely used in food packaging and envelope window materials because of its excellent transparency and printability. In recent years, for example, food packaging containers have been diversified and the shapes have been complicated, and further excellent moldability is demanded in applications using the film.
As a technique for improving the moldability of the film, for example, Patent Document 1 discloses a styrene resin composition containing a hyperbranched ultra high molecular weight copolymer and a linear polymer, According to the styrene-based resin composition, a film having high strength and excellent in moldability and stretchability during film formation and strength and deep drawability during secondary molding can be obtained.

JP, 2013-100431, A

However, in Patent Document 1, since a highly branched ultra-high molecular weight copolymer is introduced by using a solvent-soluble polyfunctional vinyl copolymer having a plurality of double bonds in one molecule, reduction of gel-like substance However, it was found that there is room for further improvement in the formability and appearance during film formation.

Therefore, the present invention has a wide range of molding conditions, excellent moldability, and a styrenic film excellent in appearance, and a molded article excellent in appearance, and a wide molding condition range, excellent in moldability, and A method for producing a styrene-based film for obtaining a styrene-based film having an excellent appearance.

The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, the degree of branching, gelation degree, and multi-angle light scattering detector (MALS) of the styrene resin composition (II) used as a raw material were used. Content of components having absolute molecular weights of 1 to 5,000,000 measured, and ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) measured using gel permeation chromatography (GPC) It was found that a styrene-based film having a wide range of molding conditions, excellent moldability, and excellent appearance can be realized by controlling the content of the styrene film in an appropriate range, and thus completed the present invention.

That is, the present invention is as shown below.
[1] A styrene film containing a styrene resin composition (I) containing rubber-like elastic particles (B) as dispersed particles in a matrix phase (A),
The matrix phase (A) is
The degree of branching is 0.70 to 0.94,
The degree of gelation is 1.00 to 1.25,
The content of components having an absolute molecular weight of 1,000,000 to 5,000,000 measured using a multi-angle light scattering detector (MALS) is 5.0 to 15.0%,
A styrene resin composition having a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured using gel permeation chromatography (GPC) of 3.0 to 5.0. (II),
The styrene resin composition (I) contains the rubber-like elastic particles (B) in an amount of 0.1 to 2.5 mass% with respect to 100 mass% of the styrene resin composition (I). Styrene film.
[2] The styrene-based film according to the above [1], wherein the maximum rising ratio of the styrene-based resin composition (II) is 1.2 to 5.0.
[3] The total residual amount of styrene dimers and trimers in the styrene resin composition (II) is 0.01 to 0.30 with respect to 100% by mass of the styrene resin composition (II). The styrene-based film according to the above [1] or [2], which is a mass%.
[4] The styrene-based film according to any one of the above [1] to [3], which has a peak top molecular weight (Mtop) of 100,000 to 180,000 measured using GPC.
[5] A molded article comprising the styrene film according to any one of the above [1] to [4].
[6] The styrene-based resin composition according to any one of [1] to [4] above, including a step of melt-kneading the styrene-based resin composition (II) and a styrene-based resin containing rubber-like elastic particles and extrusion-molding. Film manufacturing method.

According to the present invention, a wide range of molding conditions, excellent in moldability, and a styrenic film excellent in appearance, and a molded article excellent in appearance, and a wide range of molding conditions, excellent in moldability, and It is possible to provide a method for producing a styrene-based film for obtaining a styrene-based film having an excellent appearance.

It is a figure which shows the logarithmic log graph which plotted the Henky strain on the horizontal axis and the extensional viscosity on the vertical axis for the styrene resin compositions (II) obtained in Examples and Comparative Examples.

Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described, but the present invention is not limited to the present embodiment.

1. Styrene-based film The styrene-based film of the present embodiment contains the styrene-based resin composition (I) of the present embodiment, and preferably comprises the styrene-based resin composition (I) of the present embodiment.
The use of the styrene-based film of the present embodiment is not particularly limited, but in addition to the characteristics that the styrene-based resin has original rigidity and excellent optical characteristics, it is said that a film with excellent moldability and high draw ratio can be obtained. From the viewpoint, it can be suitably used as a food packaging material having a complicated shape. That is, packaging films for fresh leafy vegetables such as lettuce; envelopes, window pasting, display panels, flower packaging, cake packaging, label films, toys, ornaments, etc., especially fruit containers, lunch boxes, trays. It is suitable for use as a laminated film that has been printed, which is used to make, for example, donburi, cups, lids, and molded articles, and has few defects due to gel-like substances. It is possible to obtain a laminated sheet having excellent properties.
The thickness of the styrene-based film of this embodiment is preferably 15 to 250 μm, more preferably 20 to 100 μm.

<Styrene resin composition (I)>
The styrene resin composition (I) of the present embodiment contains the rubber-like elastic particles (B) as dispersed particles in the matrix phase (A). Further, the matrix phase (A) has a degree of branching of 0.70 to 0.94 and a degree of gelation of 1.00 to 1.25, and was measured using a multi-angle light scattering detector (MALS). The content of the component having an absolute molecular weight of 1 to 5,000,000 is 5.0 to 15.0%, and the weight average molecular weight (Mw) relative to the number average molecular weight (Mn) measured using gel permeation chromatography (GPC). ) Ratio (Mw/Mn) of 3.0 to 5.0 is a styrene resin composition (II).

The styrene resin composition (I) is typically
(1) It can be obtained by polymerizing the monomer constituting the styrene resin (a) in the styrene resin composition (II) in the presence of a rubber-like elastic body,
(2) i) a styrene resin (HIPS resin) containing styrene resin (a) obtained by polymerizing a monomer constituting styrene resin (a), and ii) rubber-like elastic particles, At least one kind of rubber-reinforced aromatic vinyl-based resin such as MBS resin and aromatic vinyl-based thermoplastic elastomer such as SBS is mixed with a known kneading machine such as a single-screw extruder, a twin-screw extruder or a Banbury mixer. It can be obtained by a method such as melt kneading.

<Matrix phase (A)>
The matrix phase (A) of the styrene resin composition (I) contained in the styrene film of the present embodiment contains the styrene resin composition (II).

<Styrene resin composition (II)>
The styrene resin composition (II) has a degree of branching of 0.70 to 0.94 and a degree of gelation of 1.00 to 1.25, and is measured using a multi-angle light scattering detector (MALS). The content of the component having an absolute molecular weight of 1 to 5,000,000 is 5.0 to 15.0%, and the weight average molecular weight (Mn) relative to the number average molecular weight (Mn) measured using gel permeation chromatography (GPC) ( The ratio (Mw/Mn) of Mw) is 3.0 to 5.0.

In the present embodiment, the degree of branching of the styrene resin composition (II), the degree of gelation, the content of components having an absolute molecular weight of 1,000,000 to 5,000,000 measured using MALS, and Mw/Mn measured using GPC. It is possible to provide a styrene-based resin composition (II) having excellent moldability, a wide range of molding conditions, and a small amount of gel-like substance by controlling the content of the styrene-based resin composition (II) in an appropriate range as described above. It is possible to obtain a styrene-based film having a wide range of molding conditions, excellent moldability, and excellent appearance.
Although not limited to theory, in the present embodiment, the styrene resin composition (II) was measured using the degree of branching, the content of components having an absolute molecular weight of 1 to 5,000,000 measured by MALS, and GPC. By controlling Mw/Mn within an appropriate range, the moldability during extrusion is improved, the range of molding conditions is widened, and by controlling the degree of gelation within an appropriate range, gelation is suppressed. It is thought to be possible.
In the present embodiment, the degree of branching of the styrene resin composition (II), the degree of gelation, the content of components having an absolute molecular weight of 1,000,000 to 5,000,000 measured using MALS, and the Mw/Mn measured using GPC. Is, for example, in the case of obtaining a styrene resin composition by radical polymerization of a monovinyl compound, the content of the conjugated divinyl compound which may be optionally contained, the polymerization reaction temperature, the residence time in the polymerization reactor, It can be controlled by the type and amount of the polymerization initiator, the type and amount of the solvent used during the polymerization, and the like.

In the present embodiment, the styrenic resin composition (II) can include, for example, a styrenic resin (a) and optionally an additive or the like.

<Molecular weight of styrene resin composition (II)>
In the present embodiment, the number average molecular weight (Mn) of the styrene resin composition (II) is preferably 50,000 to 200,000, more preferably 60,000 to 180,000, and even more preferably 7. It is 0.00-150,000.
Further, in the present embodiment, the weight average molecular weight (Mw) of the styrene resin composition (II) is preferably 200,000 to 500,000, more preferably 220,000 to 480,000, and further preferably 240,000 to. It is 450,000.
In the present embodiment, the Z-average molecular weight (Mz) of the styrene resin composition (II) is preferably 600,000 to 2,000,000, more preferably 700,000 to 1.8 million, and even more preferably 800,000 to 1.6 million. Is.

In the present embodiment, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the styrene resin composition (II) is 3.0 to 5.0, and preferably 3. 2 to 4.8, more preferably 3.5 to 4.7, and still more preferably 3.7 to 4.6. When Mw/Mn is less than 3.0, the fluidity may decrease, the moldability may decrease, and the molding condition range may narrow. When Mw/Mn is more than 5.0, the amount of low molecular weight components is extremely large, and the strength of the molded product may be reduced.
In order to set Mw/Mn to 3.0 to 5.0, for example, a method of increasing the reaction temperature during the polymerization of the styrene resin (a) in the order in which the reaction solution passes, a method of using a chain transfer agent, A method in which the type of the polymerization initiator is polyfunctional (bifunctional, trifunctional, trifunctional), a conjugated divinyl compound in the case of producing a resin by radically copolymerizing a monovinyl compound and a conjugated divinyl compound and/or a hyperbranched vinyl compound Alternatively, there is a method in which a hyperbranched vinyl compound or both are preferably added in an amount of 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ mol per 1 mol of the total amount of the monovinyl compound. Further, for example, there is a method in which polymerization is performed in two reactors under the conditions of polymerizing a low molecular weight component and a condition of polymerizing a high molecular weight component, respectively, to join the two polymerization solutions, or a method of further polymerizing after the merging. .. The conditions for polymerizing the low molecular weight component include, for example, a method of shortening the residence time in the reactor, a method of increasing the amount of the solvent to raise the polymerization temperature, a method of using a chain transfer agent, and the like. The conditions for polymerizing the high molecular weight component include, for example, a method of reducing the amount of solvent and lowering the polymerization temperature, a method of using a polyfunctional polymerization initiator, a conjugated divinyl compound or a hyperbranched vinyl compound or both of them. In addition, 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ mol is preferably added to 1 mol of the total amount of the monovinyl compound.

In the present embodiment, the peak top molecular weight (Mtop) of the styrene resin composition (II) is preferably 100,000 to 180,000, more preferably 110,000 to 180,000, and even more preferably 110,000 to 170,000. Most preferably, it is 120,000 to 160,000. If Mtop is less than 100,000, the amount of low molecular weight components will be extremely large, and the strength of the molded product may decrease. When Mtop is larger than 180,000, the fluidity may be lowered and the molding condition width may be narrowed.
In order to set Mtop in the range of 100,000 to 180,000, for example, in the case where a chain transfer agent is used or when a plurality of reactors are connected in series, the reaction solution passes through the reaction temperature during polymerization. There is a method of increasing in the order of addition, or a method of adding a chain transfer agent and a polymerization initiator to the reactor at the latter stage. Further, for example, there is a method in which polymerization is performed in two reactors under the conditions of polymerizing a low molecular weight component and a condition of polymerizing a high molecular weight component, respectively, to join the two polymerization solutions, or a method of further polymerizing after the merging. .. The conditions for polymerizing the low molecular weight component include, for example, a method of shortening the residence time in the reactor, a method of increasing the amount of the solvent to raise the polymerization temperature, a method of using a chain transfer agent, and the like. The conditions for polymerizing the high molecular weight component include, for example, a method of reducing the amount of solvent and lowering the polymerization temperature, a method of using a polyfunctional polymerization initiator, a conjugated divinyl compound or a hyperbranched vinyl compound or both of them. In addition, 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ mol is preferably added to 1 mol of the total amount of the monovinyl compound.

By adjusting the Mw/Mn of the styrene resin composition (II) to 3.0 to 5.0, the styrene resin composition (II) having more excellent moldability and fluidity can be obtained. , Mtop in the range of 100,000 to 180,000 makes it possible to obtain a styrene resin composition (II) having further excellent moldability and fluidity.
In the present disclosure, the number average molecular weight (Mn), the weight average molecular weight (Mw), the Z average molecular weight (Mz), and the peak top molecular weight (Mtop) of the styrene resin composition (II) are the gel permeation chromatography ( It is a value measured using GPC). In order to obtain each measurement sample from the film, 1 g of styrene-based film was precisely weighed, 20 mL of methyl ethyl ketone/methanol mixed solvent medium (mixing weight mass ratio 90/10) was added, and the mixture was shaken at 23° C. for 2 hours and then centrifuged. Centrifuge at 20,000 rpm for 60 minutes at 10° C. or less in a separator. The supernatant liquid after centrifugation is reprecipitated in methanol, and then filtered to collect a matrix phase, which is dried to obtain a measurement sample.

<Content of components having an absolute molecular weight of 1 to 5,000,000>
In the present embodiment, the content of the component having an absolute molecular weight of 1,000,000 to 5,000,000 in the styrene resin composition (II) is 5.0 to 15.0%, preferably 7.0 to 15.0%. It is preferably 9.0 to 15.0%, more preferably 10.0 to 14.5%, and most preferably 12.0 to 14.0%. By setting the content of the component having an absolute molecular weight of 1,000,000 to 5,000,000 to be in the range of 5.0% to 15.0%, a styrene resin composition (II) having excellent moldability and less gelled substance can be obtained. ..
In order to set the content of the component having an absolute molecular weight of 1,000,000 to 5,000,000 to 5.0 to 15.0%, for example, a method of using a polyfunctional polymerization initiator, a method of adding a conjugated divinyl compound, or a conjugate There is a method of simultaneously adding a divinyl compound and a hyperbranched vinyl compound. For example, when a styrene-based resin composition (II) is obtained by radical copolymerization by optionally adding a conjugated divinyl compound and/or a hyperbranched vinyl compound to a monovinyl compound, a conjugated divinyl compound and/or a hyperbranched compound is obtained. The addition amount of the vinyl compound is preferably 4.0×10 ^{−6 to} 8.0×10 ⁻⁴ mol per one vinyl group with respect to 1 mol of the total amount of the monovinyl compound (that is, two vinyl groups are included). In the case of the conjugated divinyl compound having, it is preferably 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ ). The number average molecular weight (Mn) of the conjugated divinyl compound and the hyperbranched vinyl compound is preferably 850 to 100,000. In the production of the styrene resin (a), there is a method in which the amount of the solvent is reduced to 0 to 20% and the reaction temperature is set to 80 to 140°C.
In the present disclosure, the content of the component having an absolute molecular weight of 1,000,000 to 5,000,000 in the styrene resin composition (II) is a value calculated using a multi-angle light scattering detector (MALS).

<Branching degree>
In the present embodiment, the degree of branching of the styrene resin composition (II) is 0.70 to 0.94, preferably 0.72 to 0.93, more preferably 0.75 to 0.92, and further preferably Is 0.79 to 0.90. If the degree of branching is less than 0.70, the number of branches will be too large and the molecular weight per branched chain will be small, so the number of entanglement points will be small, entanglement will be unraveled at high strain, and sufficient moldability will be obtained. Sometimes you can't get it. When the degree of branching is greater than 0.94, the number of branches is small, and a sufficient entanglement effect between polymer chains may not be obtained.
In order to adjust the degree of branching to 0.70 to 0.94, a method of using a polyfunctional polymerization initiator, a method of adding a conjugated divinyl compound, or a method of simultaneously adding a conjugated divinyl compound and a hyperbranched vinyl compound There is. For example, when a styrene-based resin composition (II) is obtained by radical copolymerization by optionally adding a conjugated divinyl compound and/or a hyperbranched vinyl compound to a monovinyl compound, a conjugated divinyl compound and/or a hyperbranched compound is obtained. The addition amount of the vinyl compound is preferably 4.0×10 ^{−6 to} 8.0×10 ⁻⁴ mol per one vinyl group with respect to 1 mol of the total amount of the monovinyl compound (that is, two vinyl groups are included). In the case of the conjugated divinyl compound having, it is preferably 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ ). The number average molecular weight (Mn) of the conjugated divinyl compound and the hyperbranched vinyl compound is preferably 850 to 100,000.
In the present disclosure, the degree of branching is a value calculated by the procedure described in the section of [Examples] below.

<Gelization degree>
In the present embodiment, the degree of gelation of the styrene resin composition (II) is 1.00 to 1.25, preferably 1.01 to 1.15, more preferably 1.01 to 1.12. It is preferably 1.01 to 1.10. By setting the degree of gelation in the range of 1.00 to 1.25, it is possible to suppress an increase in branching as the molecular weight increases, so that the gelled substance in the styrene resin composition (II) is lowered, Therefore, the appearance of the film can be improved. In addition, since it is possible to reduce the amount of gel-like substance that is produced when the product stays in a production facility such as a reactor for a long period of time, it is possible to improve productivity.
In order to adjust the gelation degree to 1.00 to 1.25, a method of using a polyfunctional polymerization initiator, a method of adding a conjugated divinyl compound, or a method of simultaneously adding a conjugated divinyl compound and a hyperbranched vinyl compound is used. There is a way. For example, when a styrene-based resin composition (II) is obtained by radical copolymerization by optionally adding a conjugated divinyl compound and/or a hyperbranched vinyl compound to a monovinyl compound, a conjugated divinyl compound and/or a hyperbranched compound is obtained. The addition amount of the vinyl compound is preferably 4.0×10 ^{−6 to} 8.0×10 ⁻⁴ mol per one vinyl group with respect to 1 mol of the total amount of the monovinyl compound (that is, two vinyl groups are included). In the case of the conjugated divinyl compound having, it is preferably 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ ). The number average molecular weight (Mn) of the conjugated divinyl compound and the hyperbranched vinyl compound is preferably 850 to 100,000.
In the present disclosure, the gelation degree is a value calculated by the procedure described in the section of [Examples] described later.

<Melt mass flow rate (MFR)>
In the present embodiment, the melt mass flow rate (MFR) of the styrene resin composition (II) is preferably 0.5 to 5.0 g/10 minutes. It is more preferably 0.6 to 4.0 g/10 minutes, still more preferably 0.7 to 3.5 g/10 minutes, and particularly preferably 0.8 to 3.0 g/10 minutes. By setting the melt mass flow rate in the range of 0.5 to 5.0 g/10 minutes, the styrene resin composition (II) having excellent moldability and fluidity can be obtained.
In order to set the MFR to 0.5 to 5.0 g/10 minutes, for example, Mw/Mn of the styrene resin composition (II) is set to 3.0 to 5.0, and Mw is set to 250,000 to 500,000. And a method in which a plasticizer such as liquid paraffin is added in an amount of 0.01 to 10.0% by mass based on 100% by mass of the styrene resin composition (II).
In the present disclosure, the melt mass flow rate is a value measured at 200° C. and a load of 49 N according to ISO1133.

<Maximum rise ratio>
In the present embodiment, the maximum rising ratio of the styrene resin composition (II) is preferably 1.2 to 5.0, more preferably 1.3 to 4.8, still more preferably 1.4 to 4.6. Is. In the specification of the present application, the "maximum rising ratio" means (extension viscosity of nonlinear region of maximum rising strain/elongation viscosity of linear region of maximum rising strain), and "maximum rising strain" is the maximum elongation viscosity. It means Henky distortion when. The maximum rising ratio is an index showing the degree of strain hardening at the maximum rising strain. The larger the maximum rising ratio, the greater the degree of strain hardening and the better the moldability. If the maximum rising ratio is less than 1.2, sufficient deep drawing formability may not be obtained, or the range of molding conditions tends to be narrowed. If the maximum rising ratio is more than 5.0, the elongational viscosity at the time of molding becomes too low, which is not preferable from the viewpoint of productivity.
In order to set the maximum rising ratio to 1.2 to 5.0, for example, the degree of branching is 0.70 to 0.94, and the content of components having an absolute molecular weight of 1 to 5 million is 5.0 to 15.0. There is a method to set it as %.
In the present disclosure, the maximum rising ratio is a value calculated by the procedure described in the section of [Examples] below.

<Total residual amount of styrene dimer and trimer>
In the present embodiment, when the styrene resin composition (II) is produced by radically polymerizing a styrene monomer, styrene dimers and trimers in the styrene resin composition (II) are produced. Is preferably 0.01 to 0.30% by mass, more preferably 0.01 to 0.25% by mass, and still more preferably 100% by mass to the styrene resin composition (II). It is 0.02 to 0.20 mass %. When the total residual amount of styrene dimer and trimer is 0.01 to 0.30% by mass, there is less eye blemishes during molding, and the yield of a film having a good appearance is improved, or Allows the odor of the film to be reduced.
In order to make the total residual amount of the dimer and trimer of styrene 0.01 to 0.30% by mass with respect to 100% by mass of the styrene resin composition (II), for example, the amount produced during polymerization. In order to reduce the amount of the reaction, there is a method of lowering the reaction temperature to 80 to 140° C., or a method of adding a polymerization initiator in an amount of 100 to 2000 mass ppm to generate many initiator radicals. Further, in order to reduce the amount generated by heat or shearing of the molten resin, a method of lowering the vacuum degree when vacuum devolatilizing the unreacted monomer or solvent to 50 kPa or less, or a thermal decomposition inhibitor described below is 100 to 3000. There is a method of adding mass ppm.
In the present disclosure, the total residual amount of styrene dimer and trimer is a value measured using gas chromatography (GC).

<Rubber-like elastic particles (B)>
The rubber-like elastic particles (B) of the styrene-based resin composition (I) contained in the styrene-based film of the present embodiment include the styrene-based resin inside the rubber-like elastic body and the styrene-based resin outside. The polymer is graft-polymerized.

The content of the rubber-like elastic particles (B) is 0.1 to 2.5% by mass, preferably 0.1 to 1.3% by mass, based on the mass of the styrene resin composition (I). More preferably, it is 0.1 to 0.6 mass %. If it is less than 0.1% by mass, the stability of stretching and the slipperiness may be insufficient, which may cause deterioration of the moldability of the film, which is not preferable. On the other hand, if it exceeds 2.5% by mass, the transparency, gloss and strength of the film may decrease, which is not preferable.
In the present disclosure, the content of the rubber-like elastic particles with respect to the styrene resin composition (I) is a value calculated by the procedure described in the section of [Examples] below.

As the rubber-like elastic material, polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like can be used, but polybutadiene or styrene-butadiene copolymer is preferable. As the polybutadiene, both high cis polybutadiene having a high cis content and low cis polybutadiene having a low cis content can be used. As the structure of the styrene-butadiene copolymer, both a random structure and a block structure can be used. One or more of these rubber-like elastic bodies can be used. Alternatively, a saturated rubber obtained by hydrogenating a butadiene rubber can be used.
In particular, the styrene-butadiene copolymer block copolymer can be used during the polymerization process or can be additionally added to the styrene resin composition (II) after the polymerization. In the case of additional addition, the addition amount is preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the styrene resin composition (II). This styrene-butadiene copolymer block copolymer is commercially available, and examples thereof include "Tafprene" available from Asahi Kasei Corporation.

<Melt Mass Flow Rate (MFR) of Styrenic Resin Composition (I)>
The melt mass flow rate (MFR) of the styrene resin composition (I) contained in the styrene film in the present embodiment is not particularly limited, but is preferably 0.5 to 5.0 g/10 minutes, more preferably It is 0.6 to 4.0 g/10 minutes, more preferably 0.7 to 3.5 g/10 minutes, and particularly preferably 0.8 to 3.5 g/10 minutes. By setting the melt mass flow rate of the styrene-based copolymer within the range of 0.5 to 5.0 g/10 minutes, a styrene-based film having excellent moldability and fluidity tends to be obtained.
In the present disclosure, MFR is a value measured at 200° C. and 49 N according to JIS K7210.

<Method for producing styrene resin composition (I)>
The method for producing the styrene resin composition (I) contained in the styrene film of the present embodiment is
(1) It can be obtained by polymerizing the monomer constituting the styrene resin (a) in the styrene resin composition (II) in the presence of a rubber-like elastic body,
(2) Styrene-based resin (HIPS resin) containing i) styrene-based resin (a) obtained by polymerizing monomers constituting styrene-based resin (a) and ii) rubber-like elastic particles , A rubber-reinforced aromatic vinyl-based resin such as MBS resin or at least one kind of an aromatic vinyl-based thermoplastic elastomer such as SBS, and a known kneading machine such as a single-screw extruder, a twin-screw extruder or a Banbury mixer. And a method of melt-kneading.

<Manufacturing method (1)>
As the method (1), for example, a method in which a monovinyl compound containing a styrene compound and a conjugated divinyl compound and/or a multi-branched vinyl compound are radically copolymerized in the presence of a rubber-like elastic material. (Styrenic resin (a) may have a branched structure). In this method, the raw material solution contains a monovinyl compound containing a styrene compound, a rubber-like elastic body, a conjugated divinyl compound and/or a hyperbranched vinyl compound. The conjugated divinyl compound and/or the multi-branched vinyl compound, which is a constituent of the styrene resin composition (I) contained in the styrene film of the present embodiment, may be dissolved in monovinyl compounds, a polymerization solvent, or the like, if necessary. Depending on the case, it may be added from the middle of the reactor.

From the viewpoint of controlling the polymerization reaction, a polymerization solvent, a polymerization initiator such as an organic peroxide, or a chain transfer agent can be used, if necessary.
The polymerization solvent is used in continuous bulk polymerization or continuous solution polymerization to adjust the polymerization rate, molecular weight, and the like. The polymerization solvent is not particularly limited, but includes aromatic hydrocarbons such as toluene, xylene, ethylbenzene, dialkyl ketones such as methyl ethyl ketone, which may be used alone or in combination of two or more. You may use it in combination. Further, other solvents such as aliphatic hydrocarbons can be mixed with aromatic hydrocarbons as long as the solubility of the polymerization product is not reduced. These solvents are preferably used within the range of not more than 25% by mass with respect to the monomer. When the amount of the solvent exceeds 25% by mass, the polymerization rate is remarkably reduced, and the impact strength of the obtained resin is greatly reduced. Moreover, since a large amount of energy is required for recovering the solvent, the economical efficiency is deteriorated. The solvent may be added after the polymerization has progressed to a relatively high viscosity, or may be added before the polymerization, but it is added in a proportion of 5 to 20% by mass before the polymerization. It is more preferable that the quality is uniform, and the polymerization temperature is controlled.

Particularly when it is desired to increase the amount of the conjugated divinyl compound and/or the hyperbranched vinyl compound added, it is preferable to use a polymerization solvent from the viewpoint of suppressing gelation. As a result, the amount of the conjugated divinyl compound and/or the multi-branched vinyl compound shown above can be increased, and gelation is less likely to occur.

Particularly when it is desired to increase the amount of the conjugated divinyl compound and/or the hyperbranched vinyl compound added, it is preferable to use a polymerization solvent from the viewpoint of suppressing gelation. As a result, the amount of the conjugated divinyl compound and/or the multi-branched vinyl compound shown above can be increased, and gelation is less likely to occur.

The polymerization initiator is not particularly limited, but is an organic peroxide such as 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane (PHC), n-butyl. Peroxyketals such as -4,4-bis(t-butylperoxy)valerate, di-t-butylperoxide (PBD), dialkylperoxides such as t-butylcumylperoxide, dicumylperoxide, acetylperoxide, isobutyryl Examples include diacyl peroxides such as peroxides, peroxydicarbonates such as diisopropyl peroxydicarbonate, peroxy esters such as t-butyl peroxyacetate, ketone peroxides such as acetylacetone peroxide, and hydroperoxides such as t-butyl hydroperoxide. be able to.
The polymerization initiator is preferably added in an amount of 0.005 to 0.08 mass% with respect to the styrene-based monomer.

As the chain transfer agent, for example, mercaptans such as α-methylstyrene linear dimer (αMSD), n-dodecyl mercaptan, t-dodecyl mercaptan, 1-phenyl-2-fluorene, dipentene, chloroform, terpenes, halogen compounds, and terpinolene. And the like, such as turpentine.
The amount of the chain transfer agent used is not particularly limited, but it is generally preferable to add about 0.005 to 0.3% by mass relative to the monomer.

As one example of a more specific production method, a monovinyl compound containing a styrene compound in which a rubber-like polymer is dissolved, a conjugated divinyl compound and/or a multi-branched vinyl compound, and if necessary, a polymerization solvent, a polymerization catalyst, Monomers are continuously added to equipment equipped with one or more reactors arranged in series and/or in parallel, and a devolatilization step for removing unreacted monomers by adding and mixing a chain transfer agent and the like. A so-called continuous bulk polymerization method, in which the polymer is fed in and the polymerization proceeds stepwise, is preferably used. Examples of the reactor mode include a complete mixing type, a laminar flow type, and a loop type reactor for withdrawing a part of the polymerization liquid while the polymerization is proceeding. The order of arrangement of these reactors is not particularly limited, but a laminar flow reactor is preferably used.
In the devolatilization step, for example, a normal devolatilization device such as a flash drum, a twin-screw volatilizer, a thin film evaporator, an extruder, etc. can be used. Generally, a vacuum devolatilization tank with a heater or a devolatilizer is used. An extruder or the like is used. As the arrangement of the devolatilizing device, for example, a vacuum devolatilizing tank with a heater is used in only one stage, a vacuum devolatilizing tank with a heater is connected in two stages in series, or a vacuum with a heater is used. The devolatilization tank and the devolatilization extruder are connected in series, but in order to reduce the volatile content as much as possible, a vacuum devolatilization tank with a heater connected in two stages, or heating It is preferable to connect a vacuum devolatilizing tank equipped with a vessel and a devolatilizing extruder in series.

The conditions of the devolatilization step are not particularly limited. For example, when the polymerization of the monovinyl compound is performed by bulk polymerization, the unreacted monovinyl compound is preferably 50% by mass in the styrene resin, more preferably 40% by mass. Polymerization can proceed until the amount becomes not more than mass %. By the devolatilization treatment, volatile components such as unreacted substances (monovinyl compounds) and/or solvents can be removed.

The temperature of the devolatilization treatment is usually about 190 to 280°C. The devolatilization pressure is preferably 0.1 to 50 kPa, more preferably 0.13 to 13 kPa, still more preferably 0.13 to 7 kPa, and particularly preferably 0.13 to 1.3 kPa. As the devolatilization method, for example, a method of devolatilizing under reduced pressure under heating, or a method of devolatilizing through an extruder or the like designed to remove volatile components is desirable.

The content of the styrene resin (a) in the styrene resin composition (I) is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass. The upper limit of the content of the styrene-based resin (a) may be changed depending on the content of the rubber-like elastic body (B) and the content of other addition amounts.

<Monovinyl compound>
The monovinyl compound in the present embodiment may be composed of only a styrene compound (monomer), or may be composed of a compound having another monovinyl group copolymerizable with the styrene compound together with the styrene compound. The monovinyl compound is not particularly limited as long as it can be copolymerized with a styrene compound in addition to a styrene compound, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and cetyl (meth). Examples thereof include vinyl compounds such as acrylates and (meth)acrylonitrile, and dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleic anhydride, maleimide, and nucleus-substituted maleimide. Examples of the styrene compound include styrene, α-methylstyrene, paramethylstyrene, ethylstyrene, propylstyrene, butylstyrene, chlorostyrene, bromostyrene and the like, and preferably styrene.
The content of the styrene compound is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more of the content of the monovinyl compound.

<Conjugated divinyl compound>
The conjugated divinyl compound in the present embodiment is preferably a compound having a number average molecular weight (Mn) of 850 to 100,000 and having at least two conjugated vinyl groups in the molecule.
Further, the conjugated divinyl compound in the present embodiment is preferably chain-like rather than network-like, and may or may not have a side chain in the main chain. This is because the chain shape allows the molecular chain to have a more linear shape, which tends to improve the entanglement effect. The side chain preferably has 6 or less carbon atoms, and more preferably 4 or less carbon atoms.
Furthermore, the conjugated vinyl group in the conjugated divinyl compound can be located anywhere in the molecule, but two of the at least two conjugated vinyl groups are located at different ends in the molecule. It is preferable. Further, when the conjugated divinyl compound is chain-shaped, it is more preferable that the two conjugated vinyl groups are located at different ends of the main chain (that is, both ends of the main chain are conjugated divinyl groups. Is more preferable). Polymerization reactivity can be improved by locating the conjugated vinyl group at the terminal.
Furthermore, in the case where the conjugated divinyl compound has a chain structure and has three or more conjugated vinyl groups, it is preferable that two conjugated vinyl groups among the three or more conjugated vinyl groups are located at the terminal, More preferably, all three or more conjugated vinyl groups are terminally located.
In addition, when the number of conjugated vinyl groups in the conjugated divinyl compound is large, the number of branch points increases, and gelation may easily occur in the step of recovering the reactor and the raw material, and the styrene resin (a) is transparent. The productivity may be deteriorated and the reactor and the molding machine may need to be cleaned, resulting in reduced productivity. From these viewpoints, the number of conjugated vinyl groups contained in the conjugated divinyl compound is preferably 5 or less, more preferably 4 or less, and further preferably 3 or less. From the same viewpoint, it is particularly preferable that the conjugated divinyl compound has two conjugated vinyl groups.
Here, in the present specification, the term "terminal" with respect to a molecule includes not only the position (atom) at the end of the molecule but also the position close to the position at the end of the molecule, Specifically means the end corresponding to about 20% of the extended chain length of the molecule. The conjugated vinyl group in the conjugated divinyl compound should be located at the end corresponding to 15% of the extended chain length of the conjugated divinyl compound molecule from the viewpoint of improving reactivity with the monovinyl compound and suppressing gelation. Is more preferable, it is more preferably located at the end corresponding to 10%, and even more preferably located at the end corresponding to 5%.

In the present embodiment, the conjugated vinyl group is an olefinic double bond copolymerizable with a monovinyl compound, and a structure that forms a conjugated system with the olefinic double bond (for example, but not limited to, a carbonyl group, an aryl group). Is a group having The conjugated vinyl group is not particularly limited, for example, an acryloyl group, an aryl group substituted with a vinyl group, and the structure having a conjugated vinyl group in the conjugated divinyl compound is not particularly limited, for example, Further, a structure in which (meth)acrylate, urethane (meth)acrylate, aromatic vinyl, maleic acid, fumaric acid or the like is added is also included. Note that at least two conjugated vinyl groups may be the same or different from each other.

The number average molecular weight (Mn) of the conjugated divinyl compound of the present embodiment is preferably 850 to 100,000, more preferably 1,000 to 80,000, still more preferably 1200 to 80,000, even more preferably 1500 to 60,000, particularly preferably. It is 1500 to 30000. When the number average molecular weight (Mn) is less than 850, the distance between the conjugated vinyl groups of the conjugated divinyl compound is short, the distance between the polymer chains bonded to the conjugated divinyl compound is short, and a sufficient entanglement effect cannot be obtained. However, the moldability may be poor. If the molecular weight exceeds 100,000, the distance between the conjugated vinyl groups of the conjugated divinyl compound becomes long, and the reactivity of the conjugated vinyl group at the terminal decreases (the conjugated vinyl group at the terminal reacts because the molecular weight of the conjugated divinyl compound is large. However, the production amount of the high molecular weight component may decrease.
In the present disclosure, the number average molecular weight (Mn) of the conjugated divinyl compound means the polystyrene equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC).

The main chain structure of the conjugated divinyl compound of the present embodiment is not particularly limited, and examples thereof include polyolefins such as polyethylene, polypropylene, and polyisoprene, polystyrene, polybutadiene, hydrogenated polybutadiene, polyphenylene ether, polyester, and polyphenylene sulfide. ..

As a specific conjugated divinyl compound, (hydrogenated) polybutadiene-terminated (meth)acrylate (“(hydrogenated)” means a hydrogenated or non-hydrogenated compound. The same applies hereinafter) and polyethylene. Terminal di(meth)acrylate compounds such as glycol-terminated (meth)acrylate, polypropylene glycol-terminated (meth)acrylate, ethoxylated bisphenol A-terminated (meth)acrylate, and ethoxylated bisphenol F-terminated (meth)acrylate, and (hydrogenation) Examples thereof include terminal urethane acrylate compounds such as polybutadiene terminated urethane acrylate, polyethylene glycol terminated urethane acrylate, polypropylene glycol terminated urethane acrylate, ethoxylated bisphenol A terminated urethane acrylate, and ethoxylated bisphenol F terminated urethane acrylate. For example, in the case of polypropylene glycol-terminated (meth)acrylate, the number of propylene glycol bonds as repeating units is determined so that the number average molecular weight (Mn) is 850 to 100,000. From the viewpoint of compatibility with the styrene resin, the conjugated divinyl compound is preferably (hydrogenated) polybutadiene-terminated (meth)acrylate, polystyrene-terminated (meth)acrylate, or polyphenylene ether-terminated divinyl. The term "terminal" or "both terminals" in the compound name means that the conjugated vinyl groups are located at both ends.

<Content of conjugated divinyl compound>
The content of the conjugated divinyl compound in the styrene resin (a) of the present embodiment is preferably 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ mol, and more preferably 1 mol of the total monovinyl compound. 5.0×10 ^{−6 to} 3.5×10 ⁻⁴ mol, more preferably 1.5×10 ^{−5 to} 3.0×10 ⁻⁴ mol, still more preferably 2.0×10 ⁻⁵ to 2 mol. It is 0.5×10 ⁻⁴ mol. When the content is less than 2.0×10 ⁻⁶ mol, sufficient entanglement of the polymers is unlikely to occur, strain hardening does not appear, or the degree of strain hardening is small, so that the wall thickness of the molded product is unsatisfactory. It may be uniform or the molded product may break during molding, resulting in poor moldability. On the other hand, when the content exceeds 4.0×10 ⁻⁴ mol, the gelled substance is often generated, and the appearance of the molded product may be poor.
In the present disclosure, the content of the conjugated divinyl compound with respect to 1 mol of the total amount of the monovinyl compound is a value measured using ¹ H-NMR and ¹³ C-NMR.

<Multi-branched vinyl compound>
In the multi-branched vinyl compound in the present embodiment, multi-branched means having one or more branched structures, and more specifically, a star-shaped branched structure, a pon-pon type branched structure, a graft branched structure, It means that it has an H-type branched structure.
The number average molecular weight (Mn) of the multi-branched vinyl compound is preferably 850 to 100,000, more preferably 1,000 to 80,000, still more preferably 1200 to 80,000, even more preferably 1500 to 60,000, and particularly preferably 1500 to 30,000. Is. If the number average molecular weight (Mn) is less than 850, the distance between the vinyl groups is short, so the distance between the polymer chains bonded to the conjugated divinyl compound is short, and a sufficient entanglement effect cannot be obtained, resulting in moldability. May be inferior. When the molecular weight exceeds 100,000, the distance between vinyl groups becomes long, the reactivity of vinyl groups decreases (the molecular weight of a multi-branched vinyl compound is so large that the terminal vinyl groups are difficult to react), and the high molecular weight component The amount produced may decrease.
In the present disclosure, the number average molecular weight (Mn) of the hyperbranched vinyl compound is a value measured using gel permeation chromatography (GPC).

The multi-branched vinyl compound can be synthesized, for example, by the method described in JP-A-2016-113580 or JP-A-2016-113598. For example, divinyl aromatic compounds such as divinylbenzene and diisopropenylbenzene, aliphatic and alicyclic (meth)acrylates represented by ethylene glycol di(meth)acrylate, and styrene, ethylvinylbenzene and the like. There is a method of synthesizing a hyperbranched vinyl compound by cationically polymerizing a monovinyl compound and an end modifier such as 2-phenoxyethyl methacrylate. Further, a method of esterifying or adding a vinyl group, for example, a polymerizable double bond such as an isopropenyl group to a polyhydric alcohol or a polyester polyol having a multi-branched structure and having a plurality of hydroxyl groups can be mentioned. .. The polyhydric alcohol having a multi-branched structure and a plurality of hydroxyl groups is preferably an alcohol having 2 to 100 hydroxyl groups and having 70 to 3000 carbon atoms.

<Content of hyperbranched vinyl compound>
The content of the hyperbranched vinyl compound in the styrene-based resin (a) of the present embodiment is preferably 2.0×10 ^{−6 to} 4.0×10 ⁻⁴ mol, and more preferably 1 mol of the total monovinyl compound. Is 5.0×10 ^{−6 to} 3.5×10 ⁻⁴ mol, more preferably 1.5×10 ^{−5 to} 3.0×10 ⁻⁴ mol, and still more preferably 2.0×10 ⁻⁵ to. It is 2.5×10 ⁻⁴ mol. When the content is less than 2.0×10 ⁻⁶ mol, sufficient entanglement of the polymers is unlikely to occur, strain hardening does not appear, or the degree of strain hardening is small, so that the wall thickness of the molded product is unsatisfactory. It may be uniform or the molded product may break during molding, resulting in poor moldability. On the other hand, when the content exceeds 4.0×10 ⁻⁴ mol, the gelled substance is often generated, and the appearance of the molded product may be poor.

<Additives, etc.>
The styrene-based resin composition of the present embodiment may optionally contain additives and the like, for example, 2-[1-( in order to suppress thermal decomposition of the polymer in the recovery step of unreacted monomers. A processing stabilizer such as 2-hydroxy-3,5-di-t-phenylpentyl)ethyl]-4,6-di-t-phenylpentyl acrylate may be included. Further, a heat deterioration inhibitor such as 2-[1-(2-hydroxy-3,5-di-t-phenylpentyl)ethyl]-4,6-di-t-phenylpentyl acrylate, stearic acid, zinc stearate. A higher fatty acid and its salt such as calcium stearate and magnesium stearate, a lubricant such as ethylene bisstearylamide, a plasticizer such as liquid paraffin, an antioxidant and the like in combination within a range not impairing the purpose of the present embodiment. May be. In addition, additives commonly used in the field of styrenic resins, such as flame retardants and colorants, may be combined in the styrene resin composition in a range that does not impair the purpose of the present embodiment. The additive is not particularly limited, and examples thereof include a flame retardant such as hexabromocyclododecane and a coloring agent such as titanium oxide and carbon black. When the styrene resin is used as pellets, ethylenebisstearylamide, zinc stearate, magnesium stearate or the like may be sprinkled on the pellets and used as an external lubricant for the pellets.

Antioxidants generally stabilize peroxide radicals such as hydroperoxy radicals generated during thermoforming or by exposure to light, or decompose peroxides such as hydroperoxide generated. It is a possible ingredient. The antioxidant is not particularly limited, but examples thereof include hindered phenol-based antioxidants and peroxide decomposers. The hindered phenolic antioxidant is a radical chain inhibitor, and the peroxide decomposer is capable of decomposing the peroxide generated in the system into more stable alcohols to prevent autooxidation. The hindered phenolic antioxidant is not limited to the following, but is not limited to 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3-(3,5-di- t-Butyl-4-hydroxyphenyl)propionate, 2,2′-methylenebis(4-methyl-6-t-butylphenol), 2-t-butyl-6-(3-t-butyl-2-hydroxy-5) Methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate, 4,4′ -Butylidene bis(3-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), alkylated bisphenol, tetrakis[methylene-3-(3,5-di-) t-Butyl-4-hydroxyphenyl)propionate]methane, and 3,9-bis[2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionyloxy]-1,1. -Dimethylethyl]-2,4,8,10-tetraoxyspiro[5.5]undecane and the like. Examples of the peroxide decomposer include, but are not limited to, trisnonylphenyl phosphite, triphenyl phosphite, and tris(2,4-di-t-butylphenyl)phosphite. Agents, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate Pionate), ditridecyl-3,3′-thiodipropionate, and an organic sulfur-based peroxide decomposing agent such as 2-mercaptobenzimidazole. The addition amount of the antioxidant is preferably 0.01 part by mass or more and 1 part by mass or less, more preferably 0.1 part by mass with respect to 100 parts by mass of the styrene resin (a) in the styrene resin composition (II). The amount is not less than 0.5 part by mass.

The flame retardant is not limited to the following, but from the viewpoint of flame retardancy and compatibility with styrene resins, for example, hexabromocyclododecane, brominated SBS block polymer, and 2,2-bis(4′( Examples thereof include brominated flame retardants such as 2″,3″-dibromoalkoxy)-3′,5′-dibromophenyl)-propane, and brominated bisphenol flame retardants.

Examples of the brominated bisphenol flame retardant include, but are not limited to, tetrabromobisphenol A, tetrabromobisphenol A-bis(2,3-dibromopropyl ether), and tetrabromobisphenol A-bis(2,3-dibromo). -2 methylpropyl ether), tetrabromobisphenol S, tetrabromobisphenol S-bis (2,3-dibromopropyl ether), tetrabromobisphenol S-bis (2,3-dibromo-2 methylpropyl ether), tetrabromobisphenol F, tetrabromobisphenol F-bis(2,3-dibromopropyl ether), tetrabromobisphenol F-bis(2,3-dibromo-2methylpropyl ether) tetrabromobisphenol A-bis(allyl ether), tetrabromobisphenol A polycarbonate oligomer, an epoxy group addition product of tetrabromobisphenol A oligomer, and the like are included. Among the brominated bisphenol flame retardants, especially tetrabromobisphenol A bis(2,3-dibromopropyl ether) and tetrabromobisphenol A-bis(2,3-dibromo-2methylpropyl ether) Is preferable because it is difficult to decompose during kneading with a polystyrene resin and tends to exhibit a high flame retardant effect. When tetrabromobisphenol A-bis(2,3-dibromopropyl ether) and tetrabromobisphenol A-bis(2,3-dibromo-2methylpropyl ether) are used in combination, flame retardancy and thermal stability are improved. It is more preferable because it tends to be excellent.

When using a brominated flame retardant, it is preferable to use a brominated isocyanurate flame retardant together as a flame retardant aid. Examples of the brominated isocyanurate flame retardant include, but are not limited to, mono(2,3-dibromopropyl)isocyanurate, di(2,3-dibromopropyl)isocyanurate, and tris(2,3-dibromo). Propyl) isocyanurate, mono(2,3,4-tribromobutyl) isocyanurate, di(2,3,4-tribromobutyl) isocyanurate, tris(2,3,4-tribromobutyl) isocyanurate, etc. Are listed. Among the brominated isocyanurates, tris(2,3-dibromopropyl)isocyanurate is particularly preferable because it exhibits an extremely high flame retardant effect.

The content of the bromine flame retardant is preferably 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 100 parts by mass of the styrene resin (a) in the styrene resin composition (II). Is 1 part by mass or more and 9 parts by mass or less, more preferably 2 parts by mass or more and 8 parts by mass or less. When it is 0.1 part by mass or more, flame retardancy tends to be sufficiently secured, and when it is 10 parts by mass or less, moldability tends to be sufficiently good.

The liquid paraffin can be selected from, for example, liquid paraffin defined by the standards of food hygiene law, foods, additives and the like. Specific examples of this type of liquid paraffin include, but are not limited to, Cristol N52, Cristol N62, Cristol N72, Cristol N82, Cristol N122, Cristol N172, and Crystol N72 commercially available from ExxonMobil. Stall N262, Cristol N352, Primer N542 and the like can be mentioned. Further, Moresco White P-40, Moresco White P-55, Moresco White P-60, Moresco White P-70, Moresco White P-80, and More sold by Matsumura Oil Research Institute Co., Ltd. Sco White P-85, Moresco White P-100, Moresco White P-120, Moresco White P-150, Moresco White P-200, Moresco White P-230, Moresco White P-260, Moresco White P-300, Moresco white P-350, Moresco white P-350P, etc. are mentioned. Furthermore, liquid paraffin 40-S, 60-S, 70-S, 80-S, 90-S, 100-S, 120-S, 150-S, 260-S commercially available from Sanko Chemical Industry Co., Ltd. , 350-S and the like. Also included is white mineral oil commercially available from CK Witco Corporation.

The molecular weight of the liquid paraffin is usually defined by kinematic viscosity. The liquid paraffin in the present embodiment, for example, a kinematic viscosity of 40 ° C. which is defined by the test method JIS K2283 is able to use a range of 0.1~60mm ² / sec, the 1~40mm ² / sec Those are preferable. The weight average molecular weight of the liquid paraffin is in the range of 150 to 500, preferably 180 to 450, and more preferably 200 to 350. The weight average molecular weight can be obtained by, for example, using gas chromatography and taking the weight average value of each molecular weight component of liquid paraffin. When liquid paraffin having this viscosity range or this molecular weight range is used, the obtained styrene resin composition is largely plasticized as compared with liquid paraffin having higher viscosity or higher molecular weight, and the moldability of the styrene resin composition is improved. For example, the surface gloss of a molded product tends to be greatly improved. Use of liquid paraffin having a viscosity of 0.1 mm ² /sec or more or a weight average molecular weight of 150 or more effectively prevents mold contamination and bleeding on the surface of the molded product during molding of the obtained styrene resin composition. It is preferable because it tends to be suppressed.

The content of liquid paraffin in the styrene resin composition (II) is preferably less than 3.0 parts by mass, more preferably less than 1.0 part by mass, relative to 100 parts by mass of the styrene resin (a). And more preferably less than 0.5 parts by mass. When the content of liquid paraffin is less than 5.0 parts by mass, it is possible to obtain a molded product having an excellent balance between the secondary moldability and the strength and heat resistance of the molded product.

Further, in the present embodiment, it is preferable to add the thermal deterioration inhibitor in the polymerization step or the devolatilization step of the styrene resin (a), or after the polymerization step and before the devolatilization step. In particular, it is preferable to add a thermal deterioration inhibitor after the polymerization step (preferably immediately after) and before the devolatilization step. By adding a thermal deterioration inhibitor, radicals generated by thermal decomposition can be stabilized and the amount of thermal decomposition can be reduced.

Examples of the thermal deterioration inhibitor include 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (trade name: Sumilizer GM, manufactured by Sumitomo Chemical Co., Ltd. ), 2-[1-(2-hydroxy-3,5-di-t-phenylpentyl)ethyl]-4,6-di-t-phenylpentyl acrylate (trade name: Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.), 2,4-bis(octylthiomethyl)-6-methylphenol (trade name: Irganox 1520L) such as phenolic heat deterioration inhibitor and octadecyl-3-(3,5-tert-butyl-4-hydroxyphenyl)propionate , Hindered phenolic antioxidants such as 4,6-bis(octylthiomethyl)-o-cresol, phosphorus-based processing heat stabilizers such as tris(2,4-di-tert-butylphenyl)phosphite, etc. Can be mentioned. These heat deterioration inhibitors may be used alone or in combination of two or more kinds as appropriate.

The content of the thermal deterioration inhibitor is preferably 0.01 to 0.5 parts by mass, more preferably 0.1 part by mass with respect to 100 parts by mass of the styrene resin (a) in the styrene resin composition at the outlet of the final reactor. 02 to 0.3 parts by mass, more preferably 0.03 to 0.2 parts by mass.
When the content of the thermal deterioration inhibitor is 0.01 part by mass or more, it is possible to more effectively suppress the formation of the monovinyl compound monomer and its dimer or trimer in the devolatilization step. it can. On the other hand, even if the content of the thermal deterioration inhibitor is more than 0.5 parts by mass, the effect commensurate with the content cannot be obtained.

In the present embodiment, the above-mentioned additives and the like can be obtained by using, for example, a known kneader such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, etc. in the styrene resin (a) obtained by the above-mentioned production method. It can be melt-kneaded. In addition, the above-mentioned additives and the like can be appropriately added in the above-mentioned step of producing the styrene resin (a).

<Production method (2)>
Examples of the method for producing the styrene resin (a) in the above method (2) include a method in which a monovinyl compound and a conjugated divinyl compound and/or a hyperbranched vinyl compound are radically copolymerized. (The styrene resin (a) can have a branched structure). Specific manufacturing methods include, for example, known styrene polymerization methods such as a bulk polymerization method, a solution polymerization method and a suspension polymerization method. These polymerization methods may be batch polymerization methods or continuous polymerization methods, and are preferably continuous polymerization methods from the viewpoint of productivity. As the continuous bulk polymerization method, for example, a monovinyl compound, a conjugated divinyl compound and/or a multi-branched vinyl compound, if necessary, a solvent, a polymerization catalyst, a chain transfer agent and the like are added and mixed to contain monomers. Prepare a stock solution. The above raw material solution is placed in equipment equipped with one or more reactors arranged in series and/or in parallel, and a devolatilization device for a volatilization process for removing volatile components such as unreacted monomers. A method of continuously feeding and progressively advancing the polymerization can be mentioned.

Examples of the reactor include a complete mixing type reactor, a laminar flow type reactor, and a loop type reactor for withdrawing a part of the polymerization liquid while the polymerization is proceeding. The order of arrangement of these reactors is not particularly limited.

As the method for producing the styrene-based resin (a) in the method (2), the method described in the above method (1) and various compounds (addable additions) can be used except that the rubber-like elastic body is not present in the polymerization reaction. Agent, etc.), reaction conditions and devolatilization conditions (temperature, pressure, content of various compounds, etc.) can be used.

Next, an example of a method for producing a styrene resin (HIPS) containing rubber-like elastic particles in the above method (2) will be described. The styrene resin containing rubber-like elastic particles is not particularly limited, and can be produced by any method. In a typical embodiment, a styrenic resin containing rubber-like elastic particles is prepared by polymerizing a styrenic monomer in the presence of a rubbery polymer to disperse the rubbery polymer in the styrenic polymer. Can be formed by a method that includes forming a sea-island structure.
As the styrene-based monomer constituting the styrene-based resin, in addition to styrene, α-methylstyrene, α-methyl-p-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene , Ethylstyrene, isobutylstyrene, and t-butylstyrene or styrene derivatives such as bromostyrene, chlorostyrene, and indene. From the industrial viewpoint, styrene is particularly preferable. These styrene-based monomers may be used either individually or in combination of two or more.
The method for polymerizing the styrene-based monomer is not particularly limited, and ordinary bulk polymerization, solution polymerization, suspension polymerization and the like can be performed using a solution in which rubber is dissolved in the styrene-based monomer.
Further, in order to adjust the fluidity at the time of melting, it is preferable to appropriately select and use a solvent or a chain transfer agent.
As the solvent, toluene, ethylbenzene, xylene or the like can be used. The amount of the solvent used is not particularly limited, but it is preferably used in the range of 0 to 50 mass% based on 100 mass% of the total amount of the polymerization raw material liquid.
As the chain transfer agent, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer and the like are used, and α-methylstyrene dimer is preferable. The amount of the chain transfer agent used is preferably 0.01 to 2% by mass, more preferably 0.03 to 1% by mass, further preferably 0.05 to 0.2, based on 100% by mass of the total amount of the polymerization raw material liquid. It is in the range of mass%.
The polymerization reaction temperature is preferably 80 to 200°C, more preferably 90 to 180°C. When the reaction temperature is 80° C. or higher, the productivity is good and industrially suitable, while when the reaction temperature is 200° C. or lower, the production of a large amount of low molecular weight polymer can be avoided, which is preferable. When the target molecular weight of the styrene polymer cannot be adjusted only by the polymerization temperature, it may be controlled by the amount of the initiator, the amount of the solvent, the amount of the chain transfer agent and the like. The reaction time is generally 0.5 to 20 hours, preferably 2 to 10 hours. If the reaction time is 0.5 hours or more, the reaction proceeds well, while if it is 20 hours or less, the productivity is good and it is industrially suitable.

In the present embodiment, it is preferable to add the phenolic thermal deterioration inhibitor in the above-mentioned polymerization step or devolatilization step, or after the polymerization step and before the devolatilization step. It is more preferable to add the phenol-based thermal deterioration inhibitor after the polymerization step (preferably immediately after) and before the devolatilization step.
Examples of the phenol-based heat deterioration inhibitor include 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (trade name: Sumilizer GM, Sumitomo Chemical Manufactured by Sumitomo Chemical Co., Ltd., 2-[1-(2-hydroxy-3,5-di-t-phenylpentyl)ethyl]-4,6-di-t-phenylpentyl acrylate (trade name: Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.). ) Can be mentioned.
The addition amount is preferably 0.01 to 0.5% by mass, more preferably 0.02 to 0.3% by mass, further preferably 0.03 to 0.03% by mass based on the styrene resin at the outlet of the final reactor. It is 0.2% by mass.
When the amount of the phenol-based thermal deterioration inhibitor added is 0.01 to 0.5% by mass, it is possible to more effectively suppress the formation of the monovinyl compound and its dimer or trimer in the devolatilization step. You can

(Volatilization process)
As the devolatilizing device, for example, a normal devolatilizing device such as a flash drum, a twin-screw volatilizer, a thin-film evaporator, an extruder, etc. can be used. Generally, a vacuum devolatilizing tank with a heater or a devolatilizing device is used. A volatile extruder or the like is used. As the arrangement of the devolatilizing device, for example, a vacuum devolatilizing tank with a heater is used in only one stage, a vacuum devolatilizing tank with a heater is connected in two stages in series, and a vacuum devolatilizing device with a heater is used. The thing which connected the volatilization tank and the devolatilization extruder in series, etc. are mentioned. In order to reduce volatile components as much as possible, it is preferable to connect a vacuum devolatilization tank with a heater in two stages in series, or to connect a vacuum devolatilization tank with a heater and a devolatilizing extruder in series. ..
The conditions of the devolatilization step are not particularly limited. For example, when the styrene resin is polymerized by bulk polymerization, the unreacted monovinyl compound is preferably 50% by mass or less in the styrene resin, The polymerization can proceed preferably to 40% by mass or less. By the devolatilization treatment, volatile components such as unreacted substances (monovinyl compounds) and/or solvents can be removed.
The temperature of the devolatilization treatment is usually about 190 to 280°C. The devolatilization pressure is preferably 0.1 to 50 kPa, more preferably 0.13 to 13 kPa, still more preferably 0.13 to 7 kPa, and particularly preferably 0.13 to 1.3 kPa. As the devolatilization method, for example, a method of devolatilizing under reduced pressure under heating, or a method of devolatilizing through an extruder or the like designed to remove volatile components is desirable.

Regarding the method (2), the styrene-based resin (a) thus produced and a styrene-based resin (HIPS resin) containing rubber-like elastic particles are mixed with a single-screw extruder, a twin-screw extruder, Pellets of the styrene resin composition for film can be obtained by melt-kneading with a known kneader such as a Banbury mixer. At this time, the above-mentioned additives and the like can also be added.

<Method for producing styrene film>
The above-mentioned styrene-based resin composition for a film can be easily processed by any conventionally known molding processing method, for example, inflation molding, extrusion molding, a film, a sheet, or the like. Then, the sheet is reheated and biaxially stretched in the machine direction and the transverse direction to obtain the styrene film of the present embodiment. In the present embodiment, the conditions for producing the styrene-based film are not particularly limited, for example, using an inflation processing machine, the styrene-based resin composition for a film in an extruder preheated to 160 ~ 230 ℃. A cylindrical film having a diameter larger than the die diameter can be continuously manufactured by inflating the molten resin extruded in a tube shape from a circular die through a circular die in the vertical direction while inflating it by air pressure and winding it. The film thickness and degree of stretching are controlled by the screw rotation speed, the take-up speed, and the air pressure. The film after inflation processing may be further stretched at 100 to 150°C to obtain a biaxially stretched film.

2. Laminated sheet As described above, the styrene-based film of the present embodiment has few defects due to gel-like substances and has an excellent appearance. In particular, when laminated with an expanded polystyrene sheet, a laminated sheet having excellent deep drawability can be obtained.
As a method for laminating and molding a styrene-based film in the present embodiment with a foamed polystyrene sheet, an extrusion laminating method in which a film is immediately pressure-bonded to a foamed polystyrene sheet extruded from a molding die or a Vicat softening temperature or higher, a film and a foamed polystyrene sheet. Heat-bonding method in which a film is coated with a heat roll, a dry laminating method in which a film coated with an adhesive and a polystyrene foam sheet are bonded together by a heat-bonding roll, and a HIPS resin is extruded between the film and the polystyrene foam sheet and is rolled so as to be sandwiched. A general method such as a sandwich laminating method for pressure bonding may be used.

Hereinafter, embodiments of the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

<<Measurement and evaluation method>>
The measurement and evaluation methods are as follows.

(1) Measurement of Contained Mol Number of Conjugated Divinyl Compound to 1 Mol of Styrene In the styrene-based resin composition (II), the contained molar number of conjugated divinyl compound to 1 mol of styrene is ¹ H-NMR and ¹³ C-NMR. And measured. As the measuring device, JEOL-ECA500 manufactured by JEOL Ltd. was used. Chloroform-d1 was used as a solvent, and the resonance line of tetramethylsilane was used as an internal standard.

(2) Measurement of molecular weight The number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), Mw/Mn and peak top molecular weight (Mtop) of the styrene resin composition (II) are gel permeation. The measurement was performed under the following conditions using cation chromatography (GPC).
Device: Tosoh HLC-8220
Separation column: Tosoh TSK gel Super HZM-H (internal diameter 4.6 mm) is connected in series to two guard columns: Tosoh TSK guard column Super HZ-H
Measurement solvent: Tetrahydrofuran (THF)
Sample concentration: 5 mg of a measurement sample was dissolved in 10 mL of a solvent, and filtered with a 0.45 μm filter.
Injection volume: 10 μL
Measurement temperature: 40°C
Flow rate: 0.35 mL/min Detector: Ultraviolet absorption detector (UV-8020 manufactured by Tosoh Corporation, wavelength 254 nm)
To create a calibration curve, 11 types of TSK standard polystyrene manufactured by Tosoh (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2) were used. , F-1, A-5000). A calibration curve was created using an approximate expression of a linear line.

(3) Measurement of Absolute Molecular Weight The absolute molecular weight of the styrene resin composition (II) was measured using a multi-angle light scattering detector (MALS) under the following conditions (hereinafter, sometimes referred to as “MALS method”). is there.).
Equipment: Malvern GPCmax
Separation column: Two Shodex KF806-L connected in series Guard column: Shodex GPC KFG-4A
Measurement solvent: Tetrahydrofuran (THF)
Sample concentration: 10 mg of the measurement sample was dissolved in 10 mL of the solvent, and filtered with a 0.45 μm filter.
Injection volume: 100 μL
Measurement temperature: 40°C
Flow rate: 1.00 mL/min Detector: Differential refractometer (TDA305 manufactured by Malvern)
MALS Detector: Malvern Viscotek SEC-MALS 20
MALS detection angle: 12°, 20°, 28°, 36°, 44° 52°, 60°, 68°, 76°, 84°, 90°, 100°, 108°, 116°, 124°, 132° , 140°, 148°, 156°, 164°
MALS detector temperature: 40°C
Using PS105K as a standard sample, analysis software OmniSEC5.1 was used, and it analyzed using the linear expression of a Berry plot.
The content (%) of the component having a molecular weight of 1 to 5,000,000 was calculated from the obtained molecular weight and the ratio of dW/dlogM.

(4) Measurement of degree of branching and degree of gelation The degree of branching and degree of gelation of the styrene resin composition (II) were measured and calculated by the above-mentioned MALS method. A graph in which the horizontal axis represents log Molecular weight and the vertical axis represents log radius of gyration was prepared. In this graph, for linear polystyrene (NBS706), a linear approximate straight line was created in the range of log Molecular weight of 5.0 to 6.0, and this was used as a reference value for linear polystyrene having no branched structure. And
Here, the values of log radius of gyration when the values of log Molecular weight are 6.0 and 6.5 are defined as <Rg6.0> and <Rg6.5>, respectively, and <Rg6.0> of NBS706, <Rg6.5> is defined as <Rg6.0> _NBS and <Rg6.5> _NBS , respectively. Note that <Rg6.5> _NBS can be calculated from the extrapolated value of the approximate straight line.
The degree of branching is defined as the degree of branching=<Rg6.5>/<Rg6.5> _NBS . The degree of branching, the absolute molecular weight ^{106.5 = 3.16} million, it is meant whether the rotation radius with respect NBS706 a linear polystyrene becomes how smaller and the degree of branching is small, the target polymer It represents a branch.
The gelling degree is defined as gelling degree=(<Rg6.0>/<Rg6.0> _NBS )/(<Rg6.5>/<Rg6.5> _NBS ). This gelation degree represents the rate of change in the radius of gyration of the polymer from the absolute molecular weight of 10 ^6.0 to 10 ^6.5 . That is, it means how many branches increase as the molecular weight increases, and the higher the gelation degree, the more branches increase as the molecular weight increases.

(5) Measurement of Melt Mass Flow Rate (MFR) The melt mass flow rate (g/10 minutes) of the styrene resin compositions (I) and (II) is in accordance with ISO1133 under a load condition of 200° C. and 49N. It was measured.

(6) Measurement of maximum rising ratio The maximum rising ratio of the styrene resin composition (II) was measured based on the following viscoelasticity measurement.
Device name: viscoelasticity measuring device ARES-G2 (manufactured by TA Instruments)
Measuring system: ARES-EVF option Specimen size: length 20 mm, thickness 0.7 mm, width 10 mm
Elongation strain rate: 0.01/sec Temperature: 150°C
Measurement atmosphere: in nitrogen stream Preheating time: 2 minutes Pre-stretching strain rate: 0.03/sec,
Pre-stretch length: 0.295mm
Relaxation time after pre-stretching: 2 minutes For viscoelasticity measurement, after mounting the test piece on a roller and stabilizing the temperature at the measurement temperature, the test piece was left standing for the above-mentioned preheating time and preheated. After the completion of preheating, preliminary extension was performed under the above conditions. After the pre-stretching, the sample was allowed to stand for 2 minutes to relax the stress generated by the pre-stretching and then measured.

From the results obtained by the above viscoelasticity measurement, a double logarithmic graph was created by plotting the Henky strain on the horizontal axis and the extensional viscosity on the vertical axis, and setting the range of Henky strain of 0.2 to 0.5 as the linear region. A power-approximated linear region straight line was created (eg, the dashed line in FIG. 1). When strain hardening occurs, the actual extensional viscosity becomes larger than the extensional viscosity of the approximated curve extrapolated from this linear region.
The maximum rise ratio is the Henky strain when the extensional viscosity becomes maximum in the above viscoelasticity measurement, and the maximum riser strain is defined as (the extensional viscosity of the nonlinear region at the maximum riser strain/the approximate straight line extrapolated to the linear region at the maximum riser strain). The extension viscosity was calculated.
FIG. 1 shows a logarithmic log graph in which the horizontal axis represents the Henky strain and the vertical axis represents the extensional viscosity of the styrene-based copolymers obtained in Examples and Comparative Examples.

(7) Measurement of total residual amount of styrene dimer and trimer The total residual amount (mass ppm) of styrene dimer and trimer in the styrene resin composition (II) is shown below. Measured according to conditions and procedures.
-Sample preparation: 1.0 g of the styrene resin composition (II) was dissolved in 10 mL of methyl ethyl ketone, 3 mL of methanol containing a standard substance (triphenylmethane) was further added to reprecipitate the polymer component, and the supernatant was collected and measured. It was a liquid.
・Measurement condition Equipment: Agilent 6850 series GC system Detector: FID
Column: HP-1 (100% dimethylpolysiloxane) 30 m, film thickness 0.25 μm, 0.32 mmφ
Injection volume: 1 μL (splitless)
Column temperature: Hold at 40°C for 1 minute → Raise at 20°C/min to 320°C → Hold at 320°C for 10 minutes Injection port temperature: 250°C
Detector temperature: 280℃
Carrier gas: Helium

(8) Content of Rubbery Elastic Particles in Styrene-based Film The styrene-based resin composition (II) and HIPS of each Example and Comparative Example were manufactured by Toshiba Machine Co., Ltd. at a mixing ratio shown in Table 1. Using a twin-screw extruder (TEM26SS-12-2V), the mixture was kneaded at 200° C. and 150 rpm to obtain a styrene resin composition (I).
Next, the obtained composition (I) was fitted with a ring-shaped double cylinder at the tip of a 20 mm extruder manufactured by Nakatani Machine Co., Ltd., the resin coming out of the double cylinder was inflationed, cooled, and wound by a take-up machine. Then, an inflation film having a thickness of 25 μm for each example was obtained.
1 g of the composition (I) was precisely weighed in a settling tube (this mass is W1), 20 ml of toluene was added, and the mixture was shaken at 23° C. for 2 hours, and then centrifuged (Himac, CR manufactured by Hitachi Ltd.). -20 (rotor: R20A2)) was centrifuged at 20000 rpm for 60 minutes at 10°C or lower. The settling tube was slowly tilted to about 45° and the supernatant was decanted off. Then, it was vacuum-dried under conditions of 160° C. and 3 kPa or less for 1 hour, cooled to room temperature in a desiccator, and then the mass of toluene-insoluble matter was precisely weighed (this mass is designated as W2).
The content of toluene-insoluble matter was determined by the following formula.
Toluene insoluble content (mass %)=((W2)/(W1))×100

(9) Evaluation of gel-like substance of film 20 pieces of test pieces were cut out from the styrene-based film produced by the method of (8) above to a size of 100 mm long × 100 mm wide, and the average of the short diameter and the long diameter was 2 mm or more. The material was measured visually. The number of test pieces that contained the gel-like substance was "0", "3" to 3-10 were "O", and 11 or more was "X".

(10) Evaluation of thickness uniformity of styrene-based film A square with a side of 10 cm was cut out from the center of the styrene-based film produced by the method of (8) above, and was perpendicular to the flow direction from a position 1 cm inside from the center in the flow direction. The thickness was measured at 5 points at 2 cm intervals, and the average thickness was calculated. When the number of measurement points that exceed this average thickness by ±20% is 20% or more of all the measurement points, x is given; when it is 10 to 20%, it is given ◯;

(11) Evaluation of Deep Drawability of Laminated Sheet of Styrene Film and Expanded Polystyrene Sheet 100 parts by mass of polystyrene (PS0002, G0002) talc as foam nucleating agent (average particle size 1.3 μm) ) And 4 parts by mass of liquefied butane as a foaming agent were added, and the mixture was extruded and foamed using an extrusion foaming machine equipped with a circular die having a diameter of 150 mm. The temperature of the resin melting zone of the extrusion foaming machine was adjusted to 200 to 230°C, the rotary cooler temperature was adjusted to 130 to 170°C, and the die temperature was adjusted to 145°C. The extruded foam sheet having a sheet thickness of 1.7 mm, a width of 1000 mm, and an expansion ratio of 12 was obtained by cooling the foam immediately after extrusion foaming with a cooling mandrel and cutting it at one point on the circumference with a cutter.
Next, the styrene-based film of each of the examples and comparative examples and the extruded foam sheet were heat-laminated on one side to prepare a laminated sheet. The lamination processing conditions are shown below. Thermocompression-bonding roller (heating roll having a roll surface temperature of 173° C., diameter 400 mm, roll width 1.3 m, roll speed 10 m/min), film tension 350N.
After that, using a sheet container molding machine manufactured by Soken, the laminated sheet was sandwiched between the fixed frames of the sheet molding machine, the average temperature of the heater was 200° C., the sheet temperature was 119° C., the diameter was 8 cm, and the drawing ratio was 1.0. Twenty cup-shaped containers were molded by plug assist. Whether or not tears or the like were generated on the side surface of this molded product was visually confirmed, and the number of molds that could be molded without tearing or the like was used as an index of deep draw formability.

(12) Measurement of the maximum moldable heating time of the film The heating time in the deep drawing of (11) above is extended from 10 seconds to 1 second, and vacuum molding is performed without changing other conditions to form a molded body. Ten pieces were formed. It was visually confirmed in the same manner as in (9), and the heating time was extended until the number of moldings that could be molded was 7 or less. The maximum heating time at which eight or more moldings were possible was defined as the maximum moldable heating time (seconds) of the film and measured.

"material"
The following materials were used in the examples and comparative examples.

<Styrene resin>
<Monovinyl compound>
Styrene: Styrene monomer [Asahi Kasei]

<Conjugated divinyl compound>
<Conjugated divinyl compound 1>
The conjugated divinyl compound 1 was produced based on the following method.
In a reaction vessel with a capacity of 5 L equipped with a stirrer, a thermometer and a reflux condenser, 2742 g of polybutadiene both-ends alcohol (Mn:1900), 379 g of methyl acrylate, 380 g of n-hexane, 0.8194 g of hydroquinone monomethyl ether, and 4 0.5533 g of -hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl was charged. While passing the obtained mixture through a calcium chloride tube, air was blown into the mixture to carry out reflux dehydration at 80 to 85°C. The water content of this mixture was measured by the Karl Fischer method, and it was confirmed that the water content was 200 ppm or less. Thereafter, 1.3685 g of tetra-n-butyl titanate was added to the above mixture as an ester exchange catalyst, and the produced methanol was distilled out of the reaction system under reflux of n-hexane, which was an azeotropic solvent, while stirring. At 80-85°C for 10 hours.
Next, the temperature in the reaction vessel was adjusted to 75 to 80° C., and the mixture was concentrated at a reduced pressure of 70 to 2 kPa until 95% or more of the used methyl acrylate and n-hexane were distilled, and excess methyl acrylate was added. n-Hexane was recovered. To the resulting polybutadiene both ends diacrylate 2070 g, toluene 2000 g, acetone 200 g, ion exchanged water 20g, and hydrotalcite (formula _{Mg 6 Al 2 (OH) 16CO} 3 · 4H 2 O) [manufactured by Kyowa Chemical as an ester exchange catalyst 20 g of trade name: Kyoward 500PL manufactured by Kogyo Co., Ltd. was added and treated at 75 to 80° C. for 2 hours. Next, the temperature in the reaction vessel was adjusted to 75 to 80° C., and 400 g of a mixed distillate of toluene, acetone, and water was recovered by concentrating at a reduced pressure of 90 to 35 kPa, and the obtained concentrated liquid was air-cooled. The catalyst and the adsorbent were separated by filtration under pressure, and the solvent was degassed at a temperature of 60 to 80° C. and a reduced pressure of 30 to 0.8 kPa to obtain a conjugated divinyl compound 1.
The conversion rate of the polyacrylate at both terminals of the conjugated divinyl compound 1 measured by high performance liquid chromatography (HPLC) was 99.3%. The polystyrene-equivalent number average molecular weight (Mn) measured by GPC was 1900.

Conjugated divinyl compound 2: polybutadiene diacrylate [manufactured by Tomoe Kogyo Co., Ltd.: CN307] Mn: 3800
Conjugated divinyl compound 3: polybutadiene-terminated acrylate [Osaka Organic Chemical Industry Co., Ltd.: BAC-45] Mn: 4800
Conjugated divinyl compound 4: urethane acrylate oligomer [manufactured by Tomoe Kogyo Co., Ltd.: CN9014NS] Mn: 8000

<Conjugated divinyl compound 5>
The conjugated divinyl compound 5 was produced based on the following method.
The conjugated divinyl compound 5 produced under the same conditions as the conjugated divinyl compound 1 except that the molecular weight of the alcohol at both terminals of the polybutadiene was changed to Mn: 25,000 had a conversion of diacrylate at both terminals of the polybutadiene of 99.5%. It was The polystyrene-equivalent number average molecular weight (Mn) measured by GPC was 26000.

<Conjugated divinyl compound 6>
The conjugated divinyl compound 6 was produced based on the following method.
The conjugated divinyl compound 6 produced under the same conditions as the conjugated divinyl compound 1 except that the molecular weight of the alcohol at both terminals of the polybutadiene was changed to Mn:57,000 had a conversion rate of diacrylate at both terminals of the polybutadiene of 99.2%. It was The polystyrene-equivalent number average molecular weight (Mn) measured by GPC was 58,000.

Conjugated divinyl compound 7: aromatic urethane acrylate [manufactured by Tomoe Kogyo Co., Ltd.: CN9782] Mn: 5200
Conjugated divinyl compound 8:1,3-butylenediol dimethacrylate [manufactured by Wako Pure Chemical Industries, Ltd.] Molecular weight: 226
Conjugated divinyl compound 9: NK ester A-GLY-20E [manufactured by Shin-Nakamura Chemical Co., Ltd.] Molecular weight: 1295, and the average number of conjugated vinyl in one molecule of conjugated divinyl compound 9 is 3.
Conjugated divinyl compound 10: divinylbenzene [Wako Pure Chemical Industries, Ltd.] molecular weight: 130

<Multi-branched vinyl compound>
<Multi-branched vinyl compound 1>
3.1 mol (399.4 g) of divinylbenzene, 0.7 mol (95.1 g) of ethylvinylbenzene, 0.3 mol (31.6 g) of styrene, 2.3 mol (463.5 g) of 2-phenoxyethyl methacrylate. , 974.3 g of toluene were charged into a 3.0 L reactor, 42.6 g of boron trifluoride diethyl ether complex was added at 50° C., and the reaction was carried out for 6.5 hours. After stopping the polymerization reaction with a sodium hydrogen carbonate solution, the oil layer was washed three times with pure water, and the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a polymer. The obtained polymer was washed with methanol, filtered, dried and weighed to obtain 372.5 g of a multibranched vinyl compound 1.
The weight average molecular weight (Mw) of this multi-branched vinyl compound 1 is 8000, the mole fraction of the structural unit (a1) containing a vinyl group derived from a divinyl compound is 0.44, and the diphenyl compound derived from 2-phenoxyethyl methacrylate at the end is two. The heavy bond (a2) was 0.03, and the total molar fraction (a3) of both was 0.47. Further, the radius of gyration of the polymer at a weight average molecular weight (Mw) of 8000 was 6.3 nm. The ratio of the radius of gyration of the present polymer to the mole fraction of double bonds is 13.4, and the radius of gyration at a linear weight average molecular weight (Mw) of 8000 is 15 nm. It can be seen that the hyperbranched vinyl compound 1 in the synthesis example has a branched structure.

<Multi-branched vinyl compound 2>
In a 2 liter flask equipped with a stirrer, a thermometer, a dropping funnel, and a condenser, at room temperature, 50.5 g of ethoxylated pentaerythritol (pentaerythritol with ethylene oxide) disclosed in JP-A-2016-113598, BF ₃ diethyl ether. 1 g of solution (50%) was added and heated to 110°C. To this, 450 g of 3-ethyl-3-(hydroxymethyl)oxetane was slowly added over 25 minutes while controlling the heat generated by the reaction. Once the exotherm had subsided, the reaction mixture was further stirred at 120° C. for 3 hours and then cooled to room temperature. The obtained multi-branched polyether polyol had a weight average molecular weight of 3,000 and a hydroxyl value of 530.
50 g of the multi-branched polyether polyol obtained above, 13.8 g of methacrylic acid, 150 g of toluene, 0.06 g of hydroquinone, and para were placed in a reactor equipped with a Stirrer, a thermometer, a Dean Stark decanter equipped with a condenser, and a gas introduction tube. Toluenesulfonic acid 1 g was added, and the mixture was stirred and heated under normal pressure while blowing 7% oxygen-containing nitrogen (v/v) into the mixed solution at a rate of 3 mL/min. The heating amount was adjusted so that the amount of distillate to the decanter was 30 g per hour, and heating was continued until the dehydration amount reached 2.9 g. After completion of the reaction, the mixture was once cooled, 36 g of acetic anhydride and 5.7 g of sulfamic acid were added, and the mixture was stirred at 60° C. for 10 hours. Then, in order to remove the remaining acetic acid and hydroquinone, 50 g of a 5% aqueous sodium hydroxide solution was washed four times, 50 g of a 1% aqueous sulfuric acid solution was washed once, and 50 g of water was washed twice. Metoquinone (0.02 g) was added to the obtained organic layer, and the solvent was distilled off under reduced pressure while introducing 7% oxygen-containing nitrogen (v/v) to obtain a hyperbranched vinyl compound 2 having an isopropenyl group and an acetyl group. 60 g was obtained. The weight average molecular weight of the obtained multi-branched vinyl compound 2 was 3,900, and the introduction ratios of the isopropenyl group and the acetyl group to the multi-branched polyether polyol were 30 mol% and 62 mol%, respectively, based on the entire hydroxyl groups. Met.

<Rubber-like elastic body>
HIPS1: PS Japan KK H8672

<Additive>
Thermal deterioration inhibitor 1: 2-[1-(2-hydroxy-3,5-di-t-phenylpentyl)ethyl]-4,6-di-t-phenylpentyl acrylate [Sumitomo Chemical Co., Ltd.: Sumilizer GS ]
Thermal degradation inhibitor 2: 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][ 1,3,2]Dioxaphosphine [Sumitomo Chemical Co., Ltd.: Sumilizer GP]

<Other>
Polymerization initiator 1: 2,2-bis(4,4-di-tert-butyl-peroxycyclohexyl)propane [NOF CORPORATION: Pertetra A]
Polymerization initiator 2:1,1-di-(tert-butylperoxy)cyclohexane [NOF CORPORATION Perhexa C]
Chain transfer agent 1: α-methylstyrene dimer [NOFMER MSD manufactured by NOF CORPORATION]
Foaming nucleating agent: talc (Matsumura Sangyo Co., Ltd., product name "High Filler #12"
Foaming agent: Isobutane: Mitsui Chemicals

<Example 1>
80 parts by mass of styrene monomer, 20 parts by mass of ethylbenzene, 0.031 parts by mass of the conjugated divinyl compound 1 obtained by the above-described production method (2.1×10 ⁻⁵ mol per 1 mol of styrene), polymerization initiation 0.025 parts by mass of Agent 1 was added to adjust the raw material solution supplied to the first reactor. The prepared raw material solution was continuously supplied at 0.6 L/hour to a complete mixing type first reactor having an internal volume of 5.4 L maintained at a temperature of 102°C.
Next, 80 parts by mass of styrene monomer, 20 parts by mass of ethylbenzene, 0.35 parts by mass of chain transfer agent 1 and 0.023 parts by mass of polymerization initiator 2 are added, and the raw material solution is supplied to the second reactor. Was adjusted. 0.17 L/hour of the prepared raw material solution in a plug flow type second reactor having an internal volume of 1.5 L in which the temperatures of the three zones were maintained at 122, 127 and 115° C. in the order in which the raw material solution passed. Continuously supplied.
Then, the polymerization solutions from the first reactor and the second reactor were combined, and the temperatures of the four zones were maintained at 126, 139, 140, and 140° C. in the order in which the raw material solution passed, and the internal volume of 3 L was maintained. It was supplied to a plug flow type third reactor. In zone 1 of the third reactor, 0.03 parts by mass of polymerization initiator 2 was added. Further, in zone 3 of the third reactor, 0.1 parts by mass of thermal deterioration inhibitor 1 and 0.05 parts by mass of thermal deterioration inhibitor 2 were added.
Then, the polymerization solution from the third reactor was supplied to a vacuum degassing tank heated to a temperature of 240° C. to remove volatile components such as unreacted monomers and solvents, and after a continuous operation for 72 hours, styrene-based A resin composition was obtained.
Table 1 shows the manufacturing conditions and analysis results of Example 1.
Next, the mass ratio of the styrene resin composition and HIPS1 was set to the mixing ratio shown in Table 1, and a twin-screw extruder (TEM26SS-12-2V) manufactured by Toshiba Machine Co., Ltd. was used at 200° C. and 150 rpm. And kneaded to obtain pellets of the styrene resin composition. The obtained composition was fitted with a ring-shaped double cylinder at the tip of a 20 mm extruder manufactured by Nakatani Machine Co., Ltd., the resin coming out of the double cylinder was inflationed, cooled, and wound up by a take-up machine to obtain 25 μm thick styrene. A system film was obtained.
Further, the extruded foam sheet was heat-laminated on one side with the styrene film under the condition described in (11) above to prepare a laminated sheet for evaluation.
Table 1 shows the results of various physical properties and various evaluations of Example 1.

<Examples 2 to 13>
Examples 2 to 13 were carried out in the same manner as in Example 1 except that the conditions were changed as shown in Table 1 to obtain styrene resin compositions.
The measurement and evaluation results of Examples 2 to 13 are summarized in Table 1.
As shown in FIG. 1, it was found that the styrene resin composition of Example 4 exhibited strain hardening in the measurement of ARES-EVF.

<Comparative Examples 1 to 6>
Comparative Examples 1 to 6 were carried out in the same manner as in Example 1 except that the conditions were changed as shown in Table 1 to obtain styrene resin compositions.
Table 1 summarizes the measurement and evaluation results of Comparative Examples 1 to 6.

As is clear from Table 1, in Comparative Example 1 having a small Mw/Mn of 2.8 and a large branching degree of 0.95 and Comparative Example 2 having a large branching degree of 0.95, the maximum measured by ARES-EVF was obtained. The rising ratios were all 1.00, and strain hardening did not appear. Further, in Comparative Examples 3, 5 and 6, which had high gelation degrees of 1.56, 1.29 and 1.34, respectively, the film had many gel-like substances and the appearance was not good. In Comparative Example 4 having a high branching degree of 0.97, the maximum moldable heating time was short and the molding condition range was narrow.

On the other hand, the degree of branching is 0.70 to 0.94, the degree of gelation is 1.00 to 1.25, and the absolute molecular weight measured using a multi-angle light scattering detector (MALS) is 1,000,000 to 100. The content of 5 million components is 5.0 to 15.0%, and the ratio (Mw) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured using gel permeation chromatography (GPC). /Mn) of 3.0 to 5.0, the styrenic resin compositions of Examples 1 to 13 have few gel-like substances on the film, have excellent appearance, have appropriate characteristics, and have moldability. It can be seen that it is excellent and the range of molding conditions is wide.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and can be appropriately modified without departing from the gist of the invention.

The styrene-based film of the present embodiment has a wide range of molding conditions, is excellent in moldability, and is also excellent in appearance, and it is possible to obtain a laminated sheet excellent in deep-drawing moldability by laminating with a foamed polystyrene sheet. it can. Therefore, the styrene-based film of the present embodiment can be particularly preferably used for laminating applications with, for example, expanded polystyrene sheets as styrene-based resin sheet base materials in the field of food packaging.

Claims (6)

A styrene film containing a styrene resin composition (I) containing rubber-like elastic particles (B) as dispersed particles in a matrix phase (A),
The matrix phase (A) is
The degree of branching is 0.70 to 0.94,
The degree of gelation is 1.00 to 1.25,
The content of components having an absolute molecular weight of 1,000,000 to 5,000,000 measured using a multi-angle light scattering detector (MALS) is 5.0 to 15.0%,
A styrene resin composition having a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured using gel permeation chromatography (GPC) of 3.0 to 5.0. (II),
The styrene resin composition (I) contains the rubber-like elastic particles (B) in an amount of 0.1 to 2.5 mass% with respect to 100 mass% of the styrene resin composition (I). Styrene film. The styrene-based film according to claim 1, wherein the maximum rising ratio of the styrene-based resin composition (II) is 1.2 to 5.0. The total residual amount of styrene dimers and trimers in the styrene resin composition (II) is 0.01 to 0.30 mass% with respect to 100 mass% of the styrene resin composition (II). The styrene film according to claim 1 or 2. The styrene-based film according to any one of claims 1 to 3, which has a peak top molecular weight (Mtop) measured by GPC of 100,000 to 180,000. A molded article comprising the styrene-based film according to any one of claims 1 to 4. The styrene-based film according to any one of claims 1 to 4, comprising a step of melt-kneading the styrene-based resin composition (II) and a styrene-based resin containing rubber-like elastic particles and extrusion-molding the resin. Production method.

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