Regenerated styrene resin composition, molded article thereof, and cartridge

Abstract

The present disclosure addresses the problem of providing: a regenerated styrene-based resin composition which exhibits excellent appearance and thermal creep resistance while reducing environmental burden and suppressing deterioration in mechanical strength and chemical resistance; and a molded article obtained using the regenerated styrene-based resin composition. The present disclosure is a regenerated styrene-based resin composition containing a recycled polystyrene-based resin (A) containing an osmium tetroxide-treated toluene-insoluble component (1), and a rubber-modified polystyrene-based resin (B) containing an osmium tetroxide-treated toluene-insoluble component (2), the osmium tetroxide-treated toluene-insoluble component (1) containing an osmium tetroxide-treated toluene-insoluble component (2) containing an osmium tetroxide-treated toluene-insoluble component (3). And a rubber-modified polystyrene resin (B) containing rubbery polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase, in which the osmium tetroxide-treated toluene-insoluble component (1) is more than 0 mass% and 10 mass% or less relative to the entire regenerated styrene resin composition.

Description

Technical Field

[0001] The present disclosure relates to a recycled styrene-based resin composition, and a molded article and a box obtained by molding the recycled styrene-based resin composition. Background Art

[0002] Styrene resins such as polystyrene are not only odorless and tasteless, suitable for food use, but also known as materials with low environmental impact because the components produced by complete combustion are carbon dioxide and water vapor. In particular, waste styrene resins such as internal losses generated in production processes such as styrene resin molding factories are easy to recycle because their quality and composition are clear.

[0003] However, waste styrene resins recovered from the market contain a large amount of various resins or metal powders, attachments or foreign matter other than the waste styrene resins, so it is difficult for molded products obtained by simply recycling waste styrene resins to maintain the same mechanical properties as those obtained by using new styrene resins. For example, components used in TV housings, partitions in refrigerators, and boxes of multifunction devices contain a large amount of styrene resins, so material recycling technology for these components is needed.

[0004] Patent Document 1 discloses a technique for suppressing the deterioration of the appearance design by adsorbing butylated hydroxytoluene molecules or butylated hydroxytoluene dimers, which are resin additives and cause the adhesion of deposits on the mold during molding and yellowing over time, on the zeolite using a recycled styrene resin composition containing a used styrene resin and zeolite. Patent Document 2 discloses a technique for providing a polystyrene resin having good rigidity, impact strength, moldability and flame retardancy equivalent to those of an unused polystyrene resin, providing a recycled polystyrene resin containing used resin scrap (C), a styrene thermoplastic elastomer (D), a bromine-containing flame retardant (E) and a polyfluoroolefin (F), wherein the used resin scrap (C) contains a polystyrene resin containing a flame retardant and a rubber component and a polystyrene resin not containing a rubber component.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-007424

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-087261 Summary of the invention

[0009] Problems to be solved by the invention

[0010] In the technologies of Patent Documents 1 and 2, mechanical strength and flame retardancy are studied, but chemical resistance and appearance are insufficient.

[0011] Therefore, the problem to be solved by the present disclosure is to provide a recycled styrene-based resin composition which reduces environmental load, suppresses reduction in mechanical strength, and exhibits excellent appearance, and a molded article and a box obtained by using the recycled styrene-based resin composition.

[0012] Means used to solve problems

[0013] The present inventors have conducted intensive studies in view of the above problems and have found that the content of components that cause the deterioration of the physical properties of a styrene resin composition containing a recycled polystyrene resin (A) can be quantified by osmium tetroxide treatment, and that in a composition obtained by blending a predetermined amount of a rubber-modified polystyrene (hereinafter also referred to as HIPS) as a virgin material with the recycled polystyrene resin (A), by controlling the toluene-insoluble component (1) derived from the recycled polystyrene resin (A) after osmium tetroxide treatment to a predetermined amount, a recycled styrene resin composition that suppresses the deterioration of mechanical strength and exhibits an excellent appearance, and a molded article and a box obtained by using the recycled styrene resin composition have been successfully realized, thereby completing the present invention. That is, the present disclosure is as follows.

[0014] [1] The present invention discloses a recycled styrene resin composition, which comprises a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) comprises a toluene-insoluble component (1) treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) comprises rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase, wherein:

[0015] The toluene-insoluble component (1) after the osmium tetroxide treatment of the recycled styrene-based resin composition is greater than 0% by mass and less than or equal to 10% by mass based on the entire recycled styrene-based resin composition.

[0016] [2] The present invention discloses a recycled styrene resin composition, wherein the recycled styrene resin composition contains a recycled polystyrene resin (A), rubber-like polymer particles (b2) and a polystyrene resin (b1), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) treated with osmium tetroxide,

[0017] The recycled styrene resin composition comprises:

[0018] 55% by mass or more and less than 97.9% by mass of a polymer component, wherein the polymer component comprises a polymer matrix portion (a1) of the recycled polystyrene resin (A) and the polystyrene resin (b1);

[0019] 2.1% to 35% by mass of a rubber component, wherein the rubber component comprises the rubber-like polymer particles (b2); and

[0020] The recycled polystyrene resin (A) is subjected to osmium tetroxide treatment, and the toluene-insoluble component (1) after osmium tetroxide treatment is greater than 0% by mass and less than or equal to 10% by mass.

[0021] [3] The recycled styrene resin composition according to [1], wherein the dispersoid in the composition dispersion obtained by dissolving and dispersing the recycled styrene resin composition in N,N-dimethylformamide satisfies the following formula (1):

[0022]

[0023] (In the above formula (1), d 84% The cumulative value 84% diameter in the integrated distribution curve of the particle size of the dispersoid measured by laser diffraction method, d 16% It represents the cumulative value (16% diameter) in the integrated distribution curve of the particle size of the dispersoid measured by laser diffraction method.

[0024] [4] The recycled styrene-based resin composition according to any one of [1] to [3], further comprising a styrene-based resin (C).

[0025] [5] The recycled styrene-based resin composition according to any one of [2] to [4], wherein the weight average molecular weight (Mw) of the polymer component is in the range of 100,000 to 350,000.

[0026] [6] The recycled styrene-based resin composition according to any one of [1] to [4], wherein the average particle size of all rubber-like polymer particles contained in the recycled styrene-based resin composition is in the range of 1.6 μm to 3.2 μm.

[0027] [7] The recycled styrene resin composition as described in any one of [1] to [6], wherein all the rubber-like polymer particles contained in the recycled styrene resin composition contain conjugated diene monomer units, and the content of the conjugated diene monomer units is 2% by mass to 15% by mass relative to the entire recycled styrene resin composition.

[0028] [8] The recycled styrene resin composition according to any one of [1] to [7], wherein the recycled styrene resin composition contains one or more selected from the group consisting of an antioxidant, a pigment, a flame retardant, an additive, a mineral oil, a vegetable oil and a lubricant.

[0029] [9] The recycled styrene resin composition according to any one of [1] to [8], wherein the content of the total rubber-like polymer particles is 2.1% by mass to 35% by mass based on the entire recycled styrene resin composition.

[0030]

[10] A method for producing a recycled styrene resin composition according to any one of [1] to [9], wherein the method for producing a recycled styrene resin composition comprises the following steps:

[0031] A step (I) of preparing a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) contains rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase; and

[0032] A step (II) of melt-kneading the recycled polystyrene resin (A) and the rubber-modified polystyrene resin (B).

[0033]

[11] A molded article obtained by molding the recycled styrene-based resin composition according to any one of [1] to [9].

[0034]

[12] A cartridge that can be loaded and unloaded from an image forming device that forms a multi-color or monochrome image on a recording medium by an electrophotographic method, wherein:

[0035] The cartridge includes a cartridge body, a photosensitive drum, and a charging unit for charging the surface of the photosensitive drum.

[0036] The box body contains a recycled styrene resin composition, which includes a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) after being treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) contains rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase, and relative to the entire recycled styrene resin composition, the toluene-insoluble component (1) after being treated with osmium tetroxide is greater than 0% by mass and less than or equal to 10% by mass.

[0037] Effects of the Invention

[0038] According to the present disclosure, it is possible to provide a recycled styrene-based resin composition that suppresses reduction in mechanical strength and chemical resistance and exhibits excellent appearance and excellent heat-resistant creep characteristics.

[0039] According to the present disclosure, it is possible to provide a molded article and a box obtained by using a recycled styrene-based resin composition, which suppress the reduction of mechanical strength and chemical resistance and exhibit excellent appearance and excellent heat creep resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram showing an example of the cartridge according to the present embodiment.

[0041] Figure 2 for Figure 1 A cross-sectional view of a box.

[0042] Figure 3 This is a schematic diagram showing an example in which the cartridge of the present embodiment is separated into a drum cartridge and a toner cartridge. DETAILED DESCRIPTION

[0043] Hereinafter, an embodiment of the present disclosure (hereinafter also referred to as “the present embodiment”) will be described in detail, but the scope of the present disclosure is not limited to the following description, and various modifications can be made within the scope of the gist of the disclosure.

[0044] [Recycled styrene resin composition]

[0045] The recycled styrene resin composition of the present embodiment contains a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) after being treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) contains rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase. Furthermore, the toluene-insoluble component of the recycled styrene resin composition as a whole after being treated with osmium tetroxide is greater than 0% by mass and less than or equal to 10% by mass.

[0046] Thereby, it is possible to provide a recycled styrene-based resin composition which suppresses a decrease in mechanical strength and exhibits an excellent appearance.

[0047] Another embodiment of the recycled styrene resin composition disclosed herein is a recycled styrene resin composition, wherein the recycled styrene resin composition contains a recycled polystyrene resin (A), a polystyrene resin (b1), and rubber-like polymer particles (b2), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) treated with osmium tetroxide,

[0048] The recycled styrene resin composition comprises:

[0049] 55% by mass or more and less than 97.9% by mass of a polymer component, the polymer component comprising a polymer matrix portion (a1) of the recycled polystyrene resin (A) and the polystyrene resin (b1), relative to the entire recycled styrene resin composition;

[0050] 2.1% to 35% by mass of a rubber component based on the entire recycled styrene resin composition, wherein the rubber component comprises the rubber-like polymer particles (b2); and

[0051] The toluene-insoluble component (1) after the osmium tetroxide treatment is greater than 0% by mass and less than or equal to 10% by mass based on the entire recycled styrene-based resin composition.

[0052] Thus, it is possible to provide a recycled styrene-based resin composition that suppresses reduction in mechanical strength and chemical resistance and exhibits excellent appearance and heat creep resistance.

[0053] In this embodiment, the rubber-like polymer particles (b2) and the polystyrene resin (b1) can be included in the recycled styrene resin composition in the form of a rubber-modified polystyrene resin (B) containing the rubber-like polymer particles (b2) as a domain phase and containing the polystyrene resin (b1) as a polymer matrix phase.

[0054] The polymer component, the polymer matrix part (a1) and the polystyrene resin (b1) must contain a styrene monomer unit, and optionally contain an unsaturated carboxylic acid monomer unit described below. Furthermore, the polymer component is a mixture of a polymer matrix part (a1) of a recycled polystyrene resin (A) containing a toluene-insoluble component (1) treated with osmium tetroxide and a polystyrene resin (b1), and the polystyrene resin (b1) and the rubber-like polymer particles (b2) may be materials derived from a rubber-modified polystyrene resin (B).

[0055] As the unsaturated carboxylic acid monomer, preferably a (meth)acrylic acid monomer and a (meth)acrylic acid ester monomer. As the (meth)acrylic acid monomer, for example, acrylic acid or methacrylic acid can be cited. In addition, as the (meth)acrylic acid ester monomer, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, stearyl (meth)acrylate, etc. can be cited. These substances can be used alone or in combination.

[0056] In addition, the recycled polystyrene resin (A) may contain rubber-like polymer particles (a2). That is, the recycled polystyrene resin (A) may contain used rubber-modified polystyrene resin. Therefore, when the recycled polystyrene resin (A) contains rubber-like polymer particles (a2), the recycled polystyrene resin (A) contains the polymer matrix part (a1) of the recycled polystyrene resin (A) and the rubber-like polymer particles (a2).

[0057] In addition, when the recycled polystyrene-based resin (A) contains the rubber-like polymer particles (a2), the rubber component contains the rubber-like polymer particles (a2) and the rubber-like polymer particles (b2).

[0058] When the components contained in the recycled styrene resin composition of the present embodiment are classified in terms of form, the recycled styrene resin composition can be classified into a polymer component, a rubber component, a toluene-insoluble component (1) after osmium tetroxide treatment (= a mixed substance from the recycled polystyrene resin (A)), and additional components blended as needed.

[0059] Furthermore, as the polymer component, it includes a polymer matrix part (a1) derived from a recycled polystyrene resin (A), a polystyrene resin (b1) derived from a rubber-modified polystyrene resin (B), and a styrene resin (C) compounded as required, and as the rubber component, it includes rubber-like polymer particles (b2) derived from a rubber-modified polystyrene resin (B) and rubber-like polymer particles (a2) derived from a recycled polystyrene resin (A) compounded as required. In addition, the toluene-insoluble component (1) after the osmium tetroxide treatment includes admixtures derived from the recycled polystyrene resin (A) (e.g., other resins (e.g., olefin resins such as polyethylene resins and polypropylene resins), inorganic substances (e.g., metal powders or silica), pigments, attachments, or foreign matter).

[0060] In another expression, the recycled styrene resin composition can be classified into a polymer matrix phase composed of a styrene polymer (for example, comprising the above-mentioned polymer matrix part (a1), the above-mentioned polystyrene resin (b1) and a styrene resin (C) not containing rubber-like polymer particles as required), a rubber component comprising rubber-like polymer particles (b2) dispersed (for example, in the form of islands) in the polymer matrix phase, and admixtures from the recycled polystyrene resin (A) (for example, other resins (for example, olefin resins such as polyethylene resins and polypropylene resins), inorganic substances (for example, metal powder or silica), pigments, attachments or foreign matter).

[0061] Therefore, in this specification, the polymer matrix phase composed of the styrene-based polymer is referred to as a "polymer component".

[0062] Furthermore, a component composed of the rubber-like polymer particles (b2) and the rubber-like polymer particles (a2) contained as needed is referred to as a "rubber component".

[0063] In addition, it was confirmed that the mixed material from the recycled polystyrene resin (A) was not soluble in toluene even after the osmium tetroxide treatment described later, and its amount was constant before and after the toluene dissolution treatment after the osmium tetroxide treatment. On the other hand, the polymer component is soluble in toluene. It was also confirmed that the rubber-like polymer particles (b2) and (a2) containing conjugated diene monomer units were insoluble in toluene, but became soluble in toluene when the osmium tetroxide treatment described later was performed. It should be noted that in this specification, the polymer phase contained in the rubber-like polymer particles (b2) and (a2) (for example, the polymer phase in the rubber-like polymer particles of the core-shell structure or salami structure) and the grafted polymer chains (styrene polymers) with styrene monomers on the surface of the rubber-like polymer particles are referred to as "encapsulated components". And, in this specification, for convenience, "polymer component" refers to the components soluble in toluene in the recycled styrene resin composition composed of the above-mentioned styrene polymer and before the osmium tetroxide treatment. On the other hand, the "occluded component" refers to a component obtained by subtracting the total amount of the toluene-insoluble component after the toluene-insoluble component is treated with osmium tetroxide (= the toluene-insoluble component (1) after the toluene-insoluble component is treated with osmium tetroxide) and the amount of the rubber-like polymer from the toluene-insoluble component in the recycled styrene resin composition composed of the styrene polymer before the osmium tetroxide treatment. In addition, the "toluene-insoluble component (1) after the osmium tetroxide treatment" in this specification means: the recycled styrene resin composition or the recycled polystyrene resin (A) is dissolved in toluene to separate into a toluene-soluble component and a toluene-insoluble component, and then the toluene-insoluble component is treated with osmium tetroxide to cleave the carbon-carbon double bond, and further dissolved in toluene to separate into a toluene-soluble component after the osmium tetroxide treatment and a toluene-insoluble component after the osmium tetroxide treatment, wherein the toluene-insoluble component after the osmium tetroxide treatment is referred to as "toluene-insoluble component (1) after the osmium tetroxide treatment". In the specification, for the convenience of explanation, numbers are given to distinguish the toluene-insoluble component (2) before the osmium tetroxide treatment from the toluene-insoluble component (2).

[0064] Furthermore, the inventors found that when the size of the mixed matter derived from the recycled polystyrene resin (A) shows a predetermined particle size distribution, it is less likely to become a starting point of cracking, thereby defining the relational expression of the following expression (1).

[0065] In the recycled styrene resin composition of the present embodiment, the upper limit of the content of the rubber component relative to the entire recycled styrene resin composition is preferably 35% by mass or less, less than 35% by mass, 30% by mass or less, 29% by mass or less, 28.7% by mass or less, 28.4% by mass or less, 28.1% by mass or less, 27.8% by mass or less, 27.4% by mass or less, 26% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, 12% by mass or less, 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, 5% by mass or less, 4.9% by mass or less, 4.8% by mass or less, 4.7% by mass or less, or 4.6% by mass or less. On the other hand, the lower limit of the content of the rubber component relative to the entire recycled styrene resin composition is preferably 2.1 mass % or more, 2.7 mass % or more, 3.1 mass % or more, 3.7 mass % or more, 4 mass % or more, 6 mass % or more, 7 mass % or more, 8 mass % or more, 9 mass % or more, 9.3 mass % or more, 9.5 mass % or more, or 10 mass % or more.

[0066] The above upper limit value and the above lower limit value may be combined as appropriate.

[0067] When the content of the rubber component is within the above range, the heat creep resistance and chemical resistance are improved. It should be noted that, as described below, the content of the rubber component is calculated as the value obtained by subtracting the toluene insoluble component (1) after the osmium tetroxide treatment from the toluene insoluble component (2) before the osmium tetroxide treatment.

[0068] In the recycled styrene resin composition of the present embodiment, the lower limit of the content of the polymer component is 64% by mass or more, greater than 64% by mass, 65% by mass or more, 70% by mass or more, 75% by mass or more, or 80% by mass or more relative to the entire recycled styrene resin composition. On the other hand, the upper limit of the content of the polymer component is less than 97.9% by mass, less than 97.5% by mass, less than 97% by mass, less than 96% by mass, less than 95% by mass, less than 95% by mass, less than 94.8% by mass, less than 94% by mass, less than 93% by mass, less than 92% by mass, less than 91% by mass, less than 90% by mass, or less than 90% by mass relative to the entire recycled styrene resin composition.

[0069] The above upper limit value and the above lower limit value may be combined as appropriate.

[0070] The content of the polymer component was calculated by subtracting the toluene-insoluble component (2) before the osmium tetroxide treatment from the total amount of the recycled styrene-based resin composition.

[0071] Furthermore, the polymer component may further contain a styrene-based resin (C) in addition to the polymer matrix part (a1) containing the recycled polystyrene-based resin (A) and the polystyrene-based resin (b1).

[0072] In the polymer component of the present embodiment, preferably, relative to the entire polymer component, the styrene monomer unit is 50% to 100% by mass, the (meth)acrylic acid monomer unit is 0% to 20% by mass, and the (meth)acrylate monomer unit is 0% to 50% by mass, and more preferably, the styrene monomer unit is 55% to 100% by mass, the (meth)acrylic acid monomer unit is 0% to 15% by mass, and the (meth)acrylate monomer unit is 0% to 45% by mass.

[0073] In the present embodiment, the weight average molecular weight (Mw) of the entire polymer component is preferably 100,000 to 350,000, more preferably 100,000 to 300,000, further preferably 110,000 to 280,000, further preferably 115,000 to 250,000, and particularly preferably 120,000 to 230,000. When the weight average molecular weight is 100,000 to 350,000, a resin having excellent practicality with a balance between impact strength and fluidity can be obtained. The weight average molecular weight can be measured by standard polystyrene conversion using gel permeation chromatography.

[0074] The "recycled polystyrene resin (A)" in the present specification contains a toluene-insoluble component (1) after the osmium tetroxide treatment, and the content of the toluene-insoluble component (1) after the osmium tetroxide treatment can be 10% by mass or less, preferably greater than 0% by mass and less than or equal to 5% by mass, and more preferably greater than 0% by mass and less than or equal to 3% by mass, relative to the entire recycled polystyrene resin (A). In another embodiment, the content of the toluene-insoluble component (1) is preferably 0.1% by mass to 6% by mass, and particularly preferably 1% by mass to 6% by mass, relative to the entire recycled polystyrene resin (A).

[0075] The "polystyrene resin (b1)" in this specification does not substantially contain the toluene insoluble component (2) before the osmium tetroxide treatment and the toluene insoluble component (1) after the osmium tetroxide treatment. The content of the toluene insoluble component (1) after the osmium tetroxide treatment in the polystyrene resin (b1) can be less than 0.01% by mass relative to the entire polystyrene resin (b1), and can substantially be below the detection limit.

[0076] The "styrene-based resin (C)" in this specification does not substantially contain the toluene-insoluble component (2) before the osmium tetroxide treatment and the toluene-insoluble component (1) after the osmium tetroxide treatment. The content of the toluene-insoluble component (1) after the osmium tetroxide treatment in the styrene-based resin (C) can be less than 0.01% by mass relative to the entire styrene-based resin (C), and can substantially be below the detection limit.

[0077] The upper limit of the content of the recycled polystyrene resin (A) containing the toluene-insoluble component (1) after osmium tetroxide treatment in the present embodiment is not particularly limited, and is preferably 99% by mass or less, 90% by mass or less, 80% by mass or less, 70% by mass or less, 65% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, relative to the entire recycled styrene resin composition (100% by mass).

[0078] When the content of the recycled polystyrene-based resin (A) is 70% by mass or less, more excellent impact resistance can be exhibited.

[0079] On the other hand, relative to the entire recycled styrene resin composition (100% by mass), the lower limit of the content of the recycled polystyrene resin (A) containing the toluene-insoluble component (1) after osmium tetroxide treatment in this embodiment is preferably 1% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more.

[0080] When the content of the recycled polystyrene resin (A) is 30% by mass or more, a more excellent effect of reducing environmental load can be exerted. The upper limit and the lower limit of the content of the recycled polystyrene resin (A) can be arbitrarily combined.

[0081] The upper limit of the content of the rubber-modified polystyrene resin (B) of the present embodiment is preferably 99% by mass or less, 90% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, relative to the entire recycled styrene resin composition (100% by mass).

[0082] When the content of the rubber-modified polystyrene-based resin (B) is 70% by mass or less, a more excellent effect of reducing environmental load can be exhibited.

[0083] On the other hand, the lower limit of the content of the rubber-modified polystyrene resin (B) of the present embodiment is preferably 1% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more, relative to the entire recycled styrene resin composition (100% by mass).

[0084] When the content of the rubber-modified polystyrene resin (B) is 30% by mass or more, more excellent impact resistance can be exhibited. In addition, the upper limit and the lower limit of the content of the rubber-modified polystyrene resin (B) can be arbitrarily combined.

[0085] The upper limit of the content of the rubber polymer particles (b2) in this embodiment is preferably 35 mass % or less, 33 mass % or less, 30 mass % or less, 28 mass % or less, 26 mass % or less, 25 mass % or less, or 24 mass % or less, relative to the entire recycled styrene resin composition (100 mass %).

[0086] The lower limit of the content of the rubber polymer particles (b2) of the present embodiment is preferably 2.1% by mass or more, 2.5% by mass or more, 3% by mass or more, 5% by mass or more, 7% by mass or more, 9% by mass or more, or 11% by mass or more relative to the entire recycled styrene resin composition (100% by mass). It should be noted that the content of the rubber polymer particles (b2) is calculated based on the toluene insoluble component described later.

[0087] (Preferred Form of Rubber Component)

[0088] From the viewpoint of improving impact resistance and chemical resistance, the average particle size of the rubber component of the present embodiment or the average particle size of all rubber-like polymer particles contained in the recycled styrene resin composition is preferably 1.6 μm to 3.2 μm, more preferably 1.7 μm to 2.8 μm.

[0089] The average particle size of all rubber-like polymer particles contained in the rubber component or the recycled styrene-based resin composition can be measured by the method for measuring the average particle size of rubber-like polymer particles (b2) described later.

[0090] The average particle size of all rubber polymer particles represents the average particle size of the rubber polymer particles (b2) and the rubber polymer particles (a2) as an optional component. When the average particle size and content of the rubber polymer particles are as described above, impact resistance and rigidity can be improved in a balanced manner.

[0091] (Toluene insoluble components)

[0092] In the recycled styrene resin composition of the present embodiment, the "toluene insoluble component" refers to the component that does not dissolve in toluene after adding 1 g of the recycled styrene resin composition or the recycled polystyrene resin (A) to 20 ml of toluene and shaking at 23°C for 2 hours.

[0093] Furthermore, "a recycled styrene resin composition or a recycled polystyrene resin (A) before osmium tetroxide treatment" refers to a recycled styrene resin composition or a recycled polystyrene resin (A) that has not been treated with osmium tetroxide. Therefore, the toluene-insoluble components present in the recycled styrene resin composition or the recycled polystyrene resin (A) before osmium tetroxide treatment include rubber-like polymer particles (b2) contained in the rubber-modified polystyrene resin (B), components derived from the recycled polystyrene resin (A) (rubber other than the rubber-like polymer particles (b2) (e.g., rubber-like polymer particles (a2)), metals, other resins (e.g., olefin resins such as polyethylene resins and polypropylene resins), pigments, attachments or foreign matter, etc.

[0094] On the other hand, “the recycled polystyrene resin (A) containing the toluene-insoluble component (1) after the osmium tetroxide treatment” means: the recycled polystyrene resin (A) containing the toluene-insoluble component remaining in the recycled polystyrene resin (A) after the osmium tetroxide treatment obtained by subjecting the recycled polystyrene resin (A) before the osmium tetroxide treatment to the osmium tetroxide treatment.

[0095] Furthermore, the toluene-insoluble component in the recycled styrene resin composition treated with osmium tetroxide or the recycled polystyrene resin (A) treated with osmium tetroxide contains components derived from the recycled polystyrene resin (A) (other resins (for example, olefin resins such as polyethylene resins and polypropylene resins), inorganic substances (for example, metal powder or silica), pigments, attachments or foreign matter).

[0096] As shown in the reference examples described later, when the amount of toluene-insoluble components was measured after the unused styrene-based new material containing styrene-based monomer units (for example, styrene-based resin (C) and rubber-modified polystyrene-based resin (B) as unused resins) was treated with osmium tetroxide, it was confirmed that the new material did not substantially contain toluene-insoluble components. Therefore, relative to the composition or the whole styrene-based new material, the content of toluene-insoluble components contained in the styrene-based new material after the osmium tetroxide treatment of the styrene-based new material is preferably 0.01% by mass or less, more preferably 0.001% by mass or less, and further preferably 0.0001% by mass or less, or less than the detection limit.

[0097] In the present embodiment, the method for determining the amount of toluene-insoluble components of a regenerated styrene resin composition or a recycled polystyrene resin (A) is as follows. Accurately weigh 1 g of the regenerated styrene resin composition or the recycled polystyrene resin (A) as the object of measurement into a sedimentation tube, add 20 mL of toluene, shake at 23 ° C for 2 hours, and then centrifuge (manufactured by Sakuma Seisakusho Co., Ltd., SS-2050A rotor: 6B-N6L) at a temperature of 4 ° C, a rotation speed of 20000 rpm, and a centrifugal acceleration of 45100 × G for 60 minutes. The sedimentation tube is slowly tilted at about 45 degrees, and the supernatant is decanted and removed. Accurately weigh the mass of the insoluble components containing toluene, and set the mass to W1. Then, vacuum dry for 1 hour at 160 ° C and 3 kPa or less, cool to room temperature in a dryer, and then accurately weigh the mass of the toluene-insoluble components, and set the mass to W2. Then, recover the toluene-insoluble components from the sedimentation tube.

[0098] The swelling index of the toluene insoluble component was calculated by the following formula.

[0099] Swelling index of toluene insoluble components = (W1 / W2)

[0100] (Osmium Tetroxide Treatment)

[0101] The osmium tetroxide treatment in this embodiment refers to a chemical treatment using an oxidation reaction of osmium tetroxide, which utilizes two hydroxyl groups to perform cis addition to a carbon-carbon unsaturated bond such as an alkenyl group. In addition, a catalytic amount of osmium tetroxide and an oxidant are added to a compound having a carbon-carbon unsaturated bond such as an alkenyl group (e.g., a rubber component, a toluene-insoluble component), and after conversion into a diol, the carbon-carbon unsaturated bond such as an alkenyl group can be cut by a peroxide that can be added together with osmium tetroxide. Therefore, when the recycled styrene resin composition or the recycled polystyrene resin (A) is treated with osmium tetroxide, it is confirmed that the rubber component (conjugated diene structure) contained in the recycled styrene resin composition or the recycled polystyrene resin (A) is made soluble in a solvent (for example, toluene), and mixed substances (other resins (for example, olefin resins such as polyethylene resins and polypropylene resins), inorganic substances (for example, metal powder or silica), pigments, attachments or foreign matter) derived from the recycled polystyrene resin (A) contained in the recycled styrene resin composition or the recycled polystyrene resin (A) remain.

[0102] As is clear from the above, in this specification, the mixed matter derived from the recycled polystyrene resin (A) mixed when the recycled polystyrene resin (A) is recovered for reuse is defined as the toluene-insoluble component (1) after the osmium tetroxide treatment.

[0103] The osmium tetroxide treatment in the present embodiment is not particularly limited as long as the rubber component (conjugated diene structure) contained in the regenerated styrene resin composition or the recycled polystyrene resin (A) is soluble in toluene, and is preferably performed in the following manner, for example.

[0104] The osmium tetroxide treatment in this embodiment preferably comprises the following steps: a step (I) of preparing an osmium tetroxide decomposing agent; and a step (II) of bringing the osmium tetroxide decomposing agent into contact with the toluene-insoluble component of the recycled styrene resin composition or the recycled polystyrene resin (A).

[0105] As the step (I), it is preferred that 30 mg to 500 mg (e.g., 100 mg) of osmium (VIII) oxide, 50 g to 1400 g (e.g., 200 g) of an aqueous solution of tert-butyl hydroperoxide (concentration 40% to 80% by mass, e.g., 70% by mass), and 90 ml to 1500 ml (e.g., 300 ml) of a lower alcohol (e.g., tert-butanol) are mixed to prepare an osmium tetroxide decomposition agent.

[0106] As the step (II), it is preferred to prepare a solution containing a toluene-insoluble component obtained by dissolving the above-mentioned recovered toluene-insoluble component in an organic solvent (e.g., chloroform), then add an osmium tetroxide decomposing agent to the solution containing the toluene-insoluble component, and bring the osmium tetroxide decomposing agent into contact with the toluene-insoluble component under reflux at 70°C to 90°C (e.g., in a warm water bath at 90°C) for 10 minutes to 30 minutes (e.g., 12 minutes).

[0107] In this step (II), unsaturated bonds such as olefins contained in the toluene insoluble component are decomposed.

[0108] After the above-mentioned step (II), a recovery step (III) for recovering the solid and liquid components after the decomposition treatment may be provided. As an example of the recovery step (III), it is preferred to have the following steps: a precipitation step (IV), wherein the solution containing the toluene-insoluble component to which the osmium tetroxide decomposition agent is added is cooled, and then methanol is added to the solution while stirring to precipitate the methanol-insoluble component obtained by adding the methanol; and a washing step (V), wherein the methanol-insoluble component is separated from the liquid component by using a glass filter, and the recovered product as the methanol-insoluble component is repeatedly washed with toluene, and the substance remaining on the glass filter is recovered as the toluene-insoluble component.

[0109] In the recycled styrene resin composition of the present embodiment, the toluene-insoluble component contained in the recycled styrene resin composition after the osmium tetroxide treatment is greater than 0 mass % and less than or equal to 10 mass % relative to the whole recycled styrene resin composition, preferably it can be 0.0001 mass % to 5 mass %, more preferably it can be 0.0001 mass % to 3 mass %, further preferably it can be 0.0001 mass % to 1 mass %, and particularly preferably it can be 0.0001 mass % to 0.5 mass %.

[0110] When the toluene-insoluble content in the recycled styrene resin composition after the osmium tetroxide treatment is greater than 0% by mass and less than or equal to 10% by mass, it is preferred from the viewpoint of impact resistance. In particular, when the toluene-insoluble content in the recycled styrene resin composition after the osmium tetroxide treatment is within the range of 0.0001% by mass to 1% by mass, it is preferred from the viewpoint of appearance and various mechanical properties.

[0111] Hereinafter, each component constituting the recycled styrene-based resin composition according to the present embodiment will be described.

[0112] (Recycled polystyrene resin (A))

[0113] The recycled polystyrene resin (A) of the present embodiment is a used polystyrene resin, and may be a so-called recycled product of a discarded polystyrene resin. More specifically, the recycled polystyrene resin (A) may be a material (pre-consumer material) that is recycled and reused from scraps generated in the production process of a product containing a styrene resin, a defective product of a product containing a styrene resin, a sales surplus of a styrene resin, a styrene resin that has passed the warranty period, and a styrene resin that has been discarded before being put on the market, or may be a material that is first put on the market and then recycled and reused after the consumer's use (post-consumer material).

[0114] Furthermore, the recycled polystyrene resin (A) of the present embodiment contains a toluene-insoluble component (1) after the osmium tetroxide treatment. The content of the toluene-insoluble component (1) after the osmium tetroxide treatment in the recycled polystyrene resin (A) is preferably greater than 0% by mass and less than or equal to 35% by mass, more preferably greater than 0% by mass and less than or equal to 25% by mass, still more preferably greater than 0% by mass and less than or equal to 20% by mass, still more preferably greater than 0% by mass and less than or equal to 15% by mass, and particularly preferably greater than 0% by mass and less than or equal to 10% by mass, relative to the entire recycled polystyrene resin (A).

[0115] The recycled polystyrene resin (A) that can be used in the present disclosure is not particularly limited as long as it contains 60% by mass or more of styrene monomer units relative to the entire recycled polystyrene resin (A), and the content of the toluene-insoluble component (1) after osmium tetroxide treatment is greater than 0% by mass and less than or equal to 35% by mass relative to the entire recycled polystyrene resin (A).

[0116] The recycled polystyrene-based resin (A) containing the toluene-insoluble component (1) after the osmium tetroxide treatment of the present disclosure may contain particles of the rubbery polymer (a) (=rubbery polymer particles (a2)).

[0117] In addition, the recycled polystyrene resin (A) also includes polystyrene resins recovered from used home appliances and the like. It also includes polystyrene resins containing known resins such as styrene elastomers, talc, mica, wollastonite, calcium carbonate, barium sulfate, magnesium carbonate, clay, aluminum oxide, silicon dioxide, calcium sulfate, carbon fiber, glass fiber, metal fiber, cellulose, silica sand, silica, carbon black, titanium oxide, magnesium hydroxide, asbestos, zeolite, molybdenum, diatomaceous earth, sericite, white sand, calcium hydroxide, calcium sulfite, sodium sulfate, bentonite, graphite and other inorganic fillers in the polystyrene resin. In such recycled polystyrene resin (A), usually about 0.01 to 10 parts by weight of inorganic fillers are often contained relative to 100 parts by weight of the recycled polystyrene resin (A).

[0118] In this embodiment, the weight average molecular weight (Mw) of the recycled polystyrene resin (A) before the osmium tetroxide treatment is preferably 100,000 to 400,000, more preferably 120,000 to 380,000. When the weight average molecular weight is 150,000 to 350,000, a resin having excellent practicality and a balance between impact strength and fluidity can be obtained.

[0119] The weight average molecular weight can be measured by gel permeation chromatography in terms of standard polystyrene.

[0120] In the present embodiment, when the recycled polystyrene resin (A) before the osmium tetroxide treatment contains rubber-like polymer particles (a2), a resin containing styrene monomer units obtained from styrene monomers or a polystyrene polymer (polystyrene and / or polystyrene-unsaturated carboxylic acid polymer) can be enclosed inside the rubber-like polymer particles (a2), and / or, a resin containing styrene monomer units or a polystyrene polymer can be grafted on the surface of the rubber-like polymer particles (a2). In more detail, the rubber-like polymer particles (a2) in the present embodiment only need to be particles containing the rubber-like polymer (a). Therefore, the morphology of the rubber-like polymer particles (a2) includes: solid particles composed of the rubber-like polymer (a), hollow particles composed of the rubber-like polymer (a), inner particles containing a phase containing a polystyrene polymer in the rubber-like polymer (a) (including microphase separation structure, core-shell structure and salami structure), and surface-grafted particles having a polystyrene polymer grafted on the surface. Furthermore, these forms may be provided in combination.

[0121] The rubbery polymer (a) of the present embodiment only needs to have a conjugated diene structure. Therefore, the rubbery polymer (a) is a conjugated diene polymer having a conjugated diene monomer unit, and for example, a rubber component such as polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, or acrylonitrile-butadiene copolymer can be used.

[0122] From the viewpoint of impact resistance, the average particle size of the rubber-like polymer particles (a2) contained in the recycled polystyrene-based resin (A) before the osmium tetroxide treatment of the present embodiment is preferably 0.1 μm to 4.0 μm, more preferably 0.3 μm to 3.8 μm.

[0123] The average particle size of the rubber-like polymer particles (a2) contained in the recycled polystyrene-based resin (A) before the osmium tetroxide treatment can be measured by the method for measuring the average particle size of the rubber-like polymer particles (b2) described below.

[0124] As a preferred form of the rubber-like polymer particles (a2), the following forms of the rubber-like polymer particles (b2) can be applied.

[0125] <Integral distribution curve>

[0126] In the present embodiment, the dispersoid in the regenerated styrene resin composition dispersion obtained by dissolving and dispersing the regenerated styrene resin composition in N,N-dimethylformamide preferably satisfies the following formula (1):

[0127]

[0128] (In the above formula (1), d 84% The cumulative value 84% diameter in the integrated distribution curve of the particle size of the dispersoid measured by laser diffraction method, d 16% It represents the cumulative value (16% diameter) in the integrated distribution curve of the particle size of the dispersoid measured by laser diffraction method.

[0129] Thereby, it is possible to provide a recycled styrene-based resin composition having reduced environmental load and excellent mechanical strength.

[0130] The dispersoid is composed of the toluene-insoluble component (1) (e.g., the above-mentioned mixed substance) derived from the recycled polystyrene resin (A) after osmium tetroxide treatment contained in the recycled styrene resin composition and all rubber polymer particles in the recycled styrene resin composition. In addition, in the integrated distribution curve obtained by integrating the particle size distribution of the dispersoid, the 16% diameter (d ) when the cumulative value of the frequency (%) of the dispersoid is 16% (hereinafter referred to as the cumulative value) is 16%. 16% ) and the 84% diameter (d 84% ) (hereinafter referred to as d 84% -d 16% ) divided by 2 is greater than 0 and less than 2. Thus, excellent mechanical properties are exerted. The details of the reason are unclear, but it is believed that the particles containing a large amount of toluene-insoluble components from the recycled polystyrene resin (A) after osmium tetroxide treatment as a dispersoid are relatively small particles, and therefore are not easy to become the starting point of cracking.

[0131] The laser diffraction method is used in a particle size measuring device that uses the angular distribution of the intensity of the forward diffracted light of a laser generated by a particle assumed to be spherical as a function of the particle size of the particle. More specifically, the laser diffraction method is a method in which a monochromatic light such as a laser is projected onto a flow path of a suspension in which particles assumed to be spherical are dispersed, and the diffracted light of the particle to be measured that sequentially passes through the laser and is the object of measurement is converted into a plane wave by a lens system, and the light intensity distribution in the radial direction of the plane wave is supplied to a photodetector after passing through a rotating slit, and the detection output of the photodetector is displayed to calculate the particle size distribution of the particle.

[0132] Then, the laser diffraction method provides a particle size distribution on a number basis or a volume basis, with the equivalent spherical diameter being represented on the horizontal axis and the frequency (%) being represented on the vertical axis. In this specification, the volume basis is adopted.

[0133] Therefore, in this specification, "particle size distribution" refers to the particle size distribution of the dispersoid with the equivalent spherical diameter represented on the horizontal axis and the frequency (%) represented on the vertical axis (the volume fraction (%) of the dispersoid (= the toluene-insoluble component (1) after osmium tetroxide treatment from the recycled polystyrene resin (A) and all rubber-like polymer particles in the recycled styrene resin composition) having various equivalent spherical diameters).

[0134] In this specification, the "integrated distribution curve" refers to a curve obtained by accumulating the equivalent spherical diameter of the dispersed substance when the equivalent spherical diameter is represented on the horizontal axis and the cumulative value of the frequency (%) is represented on the vertical axis. In addition, the integrated distribution curve is a function obtained by integrating the particle size distribution.

[0135] In addition, the volume fraction represents the volume ratio obtained when the particle size is measured when the dispersoid is regarded as a sphere.

[0136] In the recycled styrene resin composition of the present embodiment, in the integrated distribution curve (number-based particle size distribution) obtained by integrating the particle size distribution of the dispersoid, the 16% diameter (d 16% ) and the 84% diameter (d 84% ) (hereinafter referred to as d 84% -d 16% ) is greater than 0 μm and less than 2 μm, preferably greater than 0.1 μm and less than 1.8 μm, more preferably greater than 0.2 μm and less than 1.6 μm, and further preferably greater than 0.3 μm and less than 1.5 μm.

[0137] In the integrated distribution curve (volume-based particle size distribution) obtained by integrating the particle size distribution of the dispersoid, the 16% diameter (d 16% ) and the 84% diameter (d 84% ) (hereinafter referred to as d 84% -d 16% ) is greater than 0 μm and less than 2 μm, preferably greater than 0.4 μm and less than 1.9 μm, more preferably greater than 0.5 μm and less than 1.8 μm, and further preferably greater than 0.6 μm and less than 1.7 μm.

[0138] As the 84% -d 16%The method of controlling 1 / 2 of the absolute value of to be greater than 0 μm and less than 2 μm includes: a method of screening the recycled polystyrene resin (A) and the rubber-modified polystyrene resin (B) by passing them through a mesh after compounding (mixing), a method of crushing or pulverizing the recycled polystyrene resin (A) by a pulverizer, or a method of using the recycled polystyrene resin (A) crushed or pulverized by a pulverizer, etc. Examples of the pulverizer include a ball mill (e.g., a rotary ball mill), a roller mill, a planetary mill, a stirring mill, etc.

[0139] In the integrated distribution curve (number-based particle size distribution) of the dispersoid of the present embodiment, the 84% diameter (d 84% ) is preferably 0.5 μm or more and 6.0 μm or less, more preferably 0.6 μm or more and 5.5 μm or less, and further preferably 0.7 μm or more and 5.0 μm or less.

[0140] In the integrated distribution curve (volume-based particle size distribution) of the dispersoid of the present embodiment, the 84% diameter (d 84% ) is preferably from 1.0 μm to 8.0 μm, more preferably from 1.2 μm to 7.5 μm, and further preferably from 1.4 μm to 7.0 μm.

[0141] In the integrated distribution curve (number-based particle size distribution) of the dispersoid of the present embodiment, the 16% diameter (d 16% ) is preferably from 0.05 μm to 4.0 μm, more preferably from 0.1 μm to 3.0 μm, and even more preferably from 0.2 μm to 2.0 μm.

[0142] In the integrated distribution curve (volume-based particle size distribution) of the dispersoid of the present embodiment, the 16% diameter (d 16% ) is preferably 0.1 μm or more and 4.0 μm or less, more preferably 0.2 μm or more and 3.5 μm or less, and further preferably 0.3 μm or more and 3.0 μm or less.

[0143] <Polymer matrix part (a1)>

[0144] When the recycled polystyrene resin (A) of the present embodiment contains rubber-like polymer particles (a2), the recycled polystyrene resin (A) is composed of the toluene-insoluble component (1) after the osmium tetroxide treatment, the polymer matrix part (a1) and the rubber-like polymer particles (a2). On the other hand, when the recycled polystyrene resin (A) of the present embodiment does not contain the rubber-like polymer particles (a2), the recycled polystyrene resin (A) is composed of the toluene-insoluble component (1) after the osmium tetroxide treatment and the polymer matrix part (a1).

[0145] The polymer matrix part (a1) of this embodiment may be a styrene-based monomer homopolymer (=polystyrene), a styrene copolymer resin containing a styrene-based monomer unit and one or more monomer units selected from the group consisting of unsaturated carboxylic acid-based monomer units, or a mixture of a styrene-based monomer homopolymer and a styrene copolymer resin.

[0146] Examples of the monomer constituting the styrene-based monomer unit include styrene, α-methylstyrene, α-methyl-p-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene and tert-butylstyrene, or styrene derivatives such as bromostyrene and indene.

[0147] As the unsaturated carboxylic acid monomer, preferably a (meth)acrylic acid monomer and a (meth)acrylic acid ester monomer. As the (meth)acrylic acid monomer, for example, acrylic acid or methacrylic acid can be cited. In addition, as the (meth)acrylic acid ester monomer, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, stearyl (meth)acrylate, etc. can be cited. These substances can be used alone or in combination.

[0148] It should be noted that the composition of the polymer matrix part (a1) of the present embodiment varies depending on the recycled polystyrene resin (A) used, but it is preferably 40% to 100% by mass of the styrene monomer unit, 0% to 25% by mass of the (meth)acrylic acid monomer unit, and 0% to 50% by mass of the (meth)acrylate monomer unit relative to the entire polymer matrix part (a1).

[0149] In addition, the recycled polystyrene resin (A) of the present embodiment contains a toluene-insoluble component (2) before the osmium tetroxide treatment. The content of the toluene-insoluble component (2) before the osmium tetroxide treatment in the recycled polystyrene resin (A) includes the above-mentioned mixed substances (other resins (e.g., olefin resins such as polyethylene resins and polypropylene resins), inorganic substances (e.g., metal powders or silica), pigments, attached substances or foreign substances) and rubber-like polymer particles (a2) mixed as needed.

[0150] The content of the toluene-insoluble component (2) before the osmium tetroxide treatment varies depending on the recycled polystyrene resin (A) used, but is preferably greater than 0% by mass and less than 35% by mass, more preferably greater than 0% by mass and less than 30% by mass, further preferably greater than 0% by mass and less than 25% by mass, further preferably greater than 0% by mass and less than 20% by mass, further preferably greater than 0% by mass and less than 17% by mass, relative to the entire recycled polystyrene resin (A). As another embodiment, the content of the toluene-insoluble component (2) before the osmium tetroxide treatment is preferably greater than 21.3% by mass and less than 35% by mass, more preferably greater than 22% by mass and less than 32% by mass, relative to the entire recycled polystyrene resin (A).

[0151] Therefore, the content of the polymer matrix part (a1) can be roughly calculated by subtracting the toluene-insoluble component (2) before the osmium tetroxide treatment from the recycled polystyrene-based resin (A).

[0152] In this embodiment, the weight average molecular weight (Mw) of the polymer matrix part (a1) is preferably 100,000 to 400,000, more preferably 120,000 to 380,000. When the weight average molecular weight is 150,000 to 350,000, a resin having excellent practicality with a balance between impact strength and fluidity can be obtained.

[0153] The weight average molecular weight can be measured by gel permeation chromatography in terms of standard polystyrene.

[0154] (Rubber modified polystyrene resin (B))

[0155] The rubber-modified polystyrene resin (B) of the present embodiment contains rubber-like polymer particles (b2) constituting the domain phase and a polystyrene resin (b1) constituting the polymer matrix phase. In more detail, the rubber-modified polystyrene resin (B) is a resin in which particles of a rubber-like polymer (b) (hereinafter referred to as rubber-like polymer particles (b2)) are dispersed in the polystyrene resin (b1) as the polymer matrix phase, and can be manufactured by polymerizing a styrene monomer in the presence of the rubber-like polymer (b). In addition, examples of the polystyrene resin (b1) include polystyrene polymers (polystyrene and / or polystyrene-unsaturated carboxylic acid polymers, etc.), etc.

[0156] In addition, the rubber-modified polystyrene-based resin (B) of the present embodiment is preferably a virgin material, that is, unused.

[0157] As the styrene monomer constituting the rubber-modified polystyrene resin (B) of the present embodiment, in addition to styrene, for example, α-methylstyrene, α-methyl-p-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene and tert-butylstyrene or styrene derivatives such as bromostyrene and indene can also be listed. Styrene is particularly preferred. These styrene monomers can be used alone or in combination. It should be noted that, in the present embodiment, polystyrene refers to a homopolymer obtained by polymerizing the styrene monomer, and a commonly available polystyrene can be appropriately selected and used.

[0158] In the present embodiment, the polystyrene resin (b1) or the polystyrene resin (b1) contained in a part of the rubber-like polymer particles (b2) constituting the polymer matrix phase of the rubber-modified polystyrene resin (B) is a polymer that must contain styrene monomer units composed of the above-mentioned styrene monomers. In addition, the polymer may also be a copolymer of the above-mentioned styrene monomers and unsaturated carboxylic acid monomers. Therefore, for the monomers of the polystyrene resin (b1) or the polystyrene resin (b1) contained in a part of the rubber-like polymer particles (b2) constituting the polymer matrix phase of the rubber-modified polystyrene resin (B), as monomers other than the above-mentioned styrene monomers, unsaturated carboxylic acid monomers can also be listed. As the unsaturated carboxylic acid monomer, preferably a (meth)acrylic acid monomer and a (meth)acrylate monomer. As the (meth)acrylic acid monomer, for example, acrylic acid or methacrylic acid can be listed. In addition, examples of (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, stearyl (meth)acrylate, etc. These may be used alone or in combination.

[0159] The polystyrene-based resin (b1) constituting the polymer matrix phase of the rubber-modified polystyrene-based resin (B) is preferably one or two or more selected from the group consisting of polystyrene and styrene-unsaturated carboxylic acid copolymers.

[0160] In the present embodiment, the content of the styrene-based monomer unit is preferably 37% by mass to 98% by mass, and more preferably 49% by mass to 96% by mass, based on the entire rubber-modified polystyrene-based resin (B).

[0161] In the present embodiment, the content of the unsaturated carboxylic acid-based monomer unit is preferably 0% by mass to 63% by mass, and more preferably 0% by mass to 51% by mass, based on the entire rubber-modified polystyrene-based resin (B).

[0162] In the present embodiment, the content of the (meth)acrylic acid monomer unit is preferably 0% by mass to 3% by mass, and more preferably 0% by mass to 1% by mass, based on the entire rubber-modified polystyrene-based resin (B).

[0163] In the present embodiment, the content of the (meth)acrylic acid ester monomer unit is preferably 0% by mass to 60% by mass, and more preferably 0% by mass to 50% by mass, based on the entire rubber-modified polystyrene-based resin (B).

[0164] Regarding the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene resin (B) of the present embodiment, for example, a resin or polystyrene polymer containing a styrene monomer unit obtained from the above-mentioned styrene monomer may be contained inside the rubber-like polymer particles (b2), and / or, a resin or polystyrene polymer containing a styrene monomer unit may be grafted on the surface of the rubber-like polymer particles (b2). In more detail, the rubber-like polymer particles (b2) in the present embodiment can be particles containing a rubber-like polymer (b). Therefore, the morphology of the rubber-like polymer particles (b2) includes: solid particles composed of a rubber-like polymer (b), hollow particles composed of a rubber-like polymer (b), inner particles (including microphase separation structure, core-shell structure and salami structure) containing a phase of a polymer constituting the polystyrene resin (b1) contained in the rubber-like polymer (b), and surface grafted particles with a polymer constituting the polystyrene resin (b1) grafted on the surface. In addition, these morphologies may also be provided in a composite manner.

[0165] It should be noted that the "styrene monomer unit" in this specification refers to a repeating unit constituting a polymer formed by polymerization of a styrene monomer, which is a repeating unit (or structural unit) obtained by converting a carbon-carbon double bond in the styrene monomer into a single bond (-CC-) through a polymerization reaction or a crosslinking reaction of the styrene monomer. In addition, other "monomer units" in this specification have the same meaning.

[0166] As the rubbery polymer (b) of the present embodiment, as long as it has a conjugated diene structure. Therefore, the rubbery polymer (b) is a conjugated diene polymer with a conjugated diene monomer unit, for example, rubber components such as polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer can be used. In addition, the rubbery polymer (b) can include a form in which polystyrene resins (b1) such as polystyrene and / or polystyrene-unsaturated carboxylic acid polymers are enclosed in the rubber component. Wherein, the rubbery polymer (b) is preferably polybutadiene or styrene-butadiene copolymer. As polybutadiene, high cis-polybutadiene with a high cis-content and low cis-polybutadiene with a low cis-content can be used. In addition, as the structure of styrene-butadiene copolymer, random structure and block structure can be used. These rubbery polymers (b) can use one or more. In addition, saturated rubber obtained by hydrogenating butadiene rubber can also be used.

[0167] Since the rubber-like polymer (b) constituting the rubber-like polymer particles (b2) of the present embodiment has a conjugated diene structure, the rubber-like polymer particles (b2) can be made soluble in an organic solvent such as toluene by the osmium tetroxide treatment.

[0168] Examples of the rubber-modified polystyrene resin (B) of the present embodiment include: HIPS (high impact polystyrene), ABS resin (acrylonitrile-butadiene-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), AES resin (acrylonitrile-ethylene-propylene rubber-styrene copolymer), etc., among which HIPS (high impact polystyrene) is particularly preferred.

[0169] When the rubber-modified polystyrene resin (B) is a HIPS resin, among these rubbery polymers (b), high cis-polybutadiene having cis-1,4 bonds of 90 mol% or more is particularly preferred. The high cis-polybutadiene preferably has vinyl 1,2 bonds of 6 mol% or less, and particularly preferably has vinyl 1,2 bonds of 3 mol% or less.

[0170] The content of the compound having a cis-1,4 structure, a trans-1,4 structure or a vinyl-1,2 structure, which is an isomer related to the structural unit of the high cis-polybutadiene, can be calculated by measuring with an infrared spectrophotometer and performing data processing by the Morero method.

[0171] The high-cis polybutadiene can be easily obtained by a known production method, for example, by polymerizing 1,3-butadiene using a catalyst containing an organic aluminum compound and a cobalt compound or a nickel compound.

[0172] In the present embodiment, when a conjugated diene polymer containing a (meth)acrylonitrile monomer unit such as an acrylonitrile monomer unit is used as a material for the rubbery polymer particles (b2) or the rubbery polymer (b), the content of the (meth)acrylonitrile monomer unit is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 3% by mass or less, and particularly preferably 0.7% by mass or less, relative to the entire recycled styrene resin composition (100% by mass).

[0173] Relative to the total amount of 100 mass % of the rubber-modified polystyrene resin (B), the content of the rubber-like polymer (b) contained in the rubber-modified polystyrene resin (B) of the present embodiment is preferably 2 mass % to 15 mass %, more preferably 2.2 mass % to 10 mass %, and further preferably 2.4 mass % to 8 mass %. From other viewpoints, it is preferably 2.6 mass % to 6 mass %, and more preferably 3 mass % to 5 mass %. When the content of the rubber-like polymer (b) is less than 2 mass %, it is possible that the impact resistance is reduced. In addition, when the content of the rubber-like polymer (b) is greater than 15 mass %, it is possible that the gloss is reduced and the bending creep characteristics are reduced.

[0174] In addition, in this disclosure, the content of the rubber-like polymer (b) contained in the rubber-modified polystyrene-based resin (B) (so-called polybutadiene content) is a value calculated using pyrolysis gas chromatography.

[0175] The content of the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene resin (B) of the present embodiment (toluene-insoluble component in the rubber-modified polystyrene resin (B)) is preferably 8% to 35% by mass relative to 100% by mass of the total amount of the rubber-modified polystyrene resin (B).

[0176] It should be noted that in the present disclosure, the content of the rubber-like polymer particles (b2) or all the rubber-like polymer particles contained in the rubber-modified polystyrene resin (B) or the recycled styrene resin composition corresponds to the toluene-insoluble component of the resin (B) or the composition before the osmium tetroxide treatment. Specifically, it is calculated by the following method.

[0177] For the determination of the content (mass %) of the rubber-like polymer particles (b2) in the composition, 1 g of the resin or composition to be measured was accurately weighed into a sedimentation tube (this mass was designated as W), 20 mL of toluene was added, and the mixture was shaken at 23° C. for 2 hours, and then centrifuged for 60 minutes at 5° C. or less and 20,000 rpm (centrifugal acceleration: 4510 G) using a centrifuge (manufactured by Sakuma Seisakusho, SS-2050A). Then, the sedimentation tube was slowly tilted at about 45 degrees, the supernatant was decanted and removed, and the obtained insoluble components were vacuum dried at 160° C. and 3 kPa or less for 1 hour, cooled to room temperature in a desiccator, and then the mass of the toluene insoluble components was accurately weighed (this mass was designated as G), and the content (mass %) of the rubber-like polymer particles (b2) was calculated by the following formula.

[0178] Content of rubbery polymer particles (b2) = (G / W) × 100

[0179] From the perspective of impact resistance, the average particle size of the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene resin (B) of the present embodiment is preferably 0.5 μm to 3.0 μm, and more preferably 0.8 μm to 2.8 μm. From other perspectives, it is preferably 0.55 μm to 3.2 μm, and more preferably 0.65 μm to 2.8 μm. When the average particle size of the rubber-like polymer particles (b2) is less than 0.5 μm or greater than 3.0 μm, it is possible that the impact strength and chemical resistance become insufficient, or the gloss is reduced.

[0180] In addition, in this disclosure, the average particle diameter of the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene-based resin (B) can be measured by the following method.

[0181] The ultrathin sections with a thickness of 75nm were made by utilizing the rubber-modified polystyrene resin (B) after osmium tetroxide staining, and the photo with a magnification of 10000 times was taken using an electron microscope. In the photo, the particles dyed black are rubber-like polymer particles (b2). The area average particle diameter is calculated by the following formula (N1) by the photo, and the average particle diameter of the rubber-like polymer particles (b2) is used as the average particle diameter. For this determination, the photo is input into a scanner with a resolution of 200dpi, and the particle analysis software of image analysis device IP-1000 (manufactured by Asahi Chemical Industry Co., Ltd.) is used to measure.

[0182]

[0183] (In the above formula (N1), ni is the number of rubber-like polymer particles (b2) having a particle diameter Dri, and the particle diameter Dri is the particle diameter calculated from the area of ​​the particles in the photograph as an equivalent circle diameter.)

[0184] The reduced viscosity of the rubber-modified polystyrene resin (B), which is an indicator of the molecular weight of the rubber-modified polystyrene resin (B), is preferably in the range of 0.50 dL / g to 0.85 dL / g, and more preferably in the range of 0.55 dL / g to 0.80 dL / g. When the reduced viscosity of the rubber-modified polystyrene resin (B) is less than 0.50 dL / g, the impact strength may be reduced, and when the reduced viscosity of the rubber-modified polystyrene resin (B) is greater than 0.85 dL / g, the moldability may be reduced due to the reduction in fluidity.

[0185] In addition, in this disclosure, the reduced viscosity of the rubber-modified polystyrene-based resin (B) is a value measured under the conditions of 30° C. and a concentration of 0.5 g / dL in a toluene solution.

[0186] In the present embodiment, the weight average molecular weight (Mw) of the polystyrene resin (b1) in the rubber-modified polystyrene resin (B) is preferably 100,000 to 350,000, and more preferably 127,000 to 250,000. In another embodiment, the weight average molecular weight (Mw) of the polystyrene resin (b1) may be 110,000 to 235,000, 120,000 to 224,000, or 123,000 to 193,000. When the weight average molecular weight is 100,000 to 350,000, a resin having excellent practicality with a balance between impact strength and fluidity can be obtained.

[0187] The weight average molecular weight can be measured by gel permeation chromatography in terms of standard polystyrene.

[0188] The method for producing the rubber-modified polystyrene resin (B) of the present embodiment is not particularly limited, and the resin can be produced by bulk polymerization (or solution polymerization) in which a styrene monomer and an optionally added unsaturated carboxylic acid monomer (and a solvent) are polymerized in the presence of a rubber-like polymer (b), or by bulk-suspension polymerization in which the reaction is transferred to suspension polymerization in the middle of the reaction, or by emulsion graft polymerization in which a styrene monomer and an optionally added unsaturated carboxylic acid monomer are polymerized in the presence of a latex of a rubber-like polymer (b). In bulk polymerization, the resin can be produced by continuously supplying a mixed solution to which a rubber-like polymer (b), a styrene monomer, an optionally added unsaturated carboxylic acid monomer, and an organic solvent, an organic peroxide, and / or a chain transfer agent are added as needed to a polymerization apparatus having a complete mixing reactor or a tank reactor connected in series with a plurality of tank reactors.

[0189] In the present embodiment, the melt flow rate of the rubber-modified polystyrene resin (B) at 200°C is preferably 0.3 g / 10 min to 10.0 g / 10 min, more preferably 0.5 g / 10 min to 8.0 g / 10 min, and further preferably 0.7 g / 10 min to 7.0 g / 10 min. If the above melt flow rate is in the range of 0.3 g / 10 min to 10.0 g / 10 min, the miscibility with the recycled polystyrene resin (A) is good, and the mechanical strength is also good. In the present disclosure, the melt flow rate is a value measured under the conditions of 200°C and a load of 49 N according to ISO 1133.

[0190] The above are essential components of the recycled styrene resin composition of the present embodiment. Hereinafter, the styrene resin (C) and optional additional components as optional components of the recycled styrene resin composition of the present embodiment will be described.

[0191] (Styrene resin (C))

[0192] The recycled styrene resin composition of the present embodiment may further contain a styrene resin (C) in addition to the recycled polystyrene resin (A) and the rubber-modified polystyrene resin (B).

[0193] The styrene-based resin (C) of the present embodiment essentially contains a styrene-based monomer unit, and may contain a monomer unit derived from an unsaturated carboxylic acid-based monomer copolymerizable with the styrene-based monomer as required.

[0194] Examples of the styrene-based monomer include the same styrene-based monomers as those mentioned above for the rubber-modified polystyrene-based resin (B), and therefore their description is omitted here.

[0195] Examples of the unsaturated carboxylic acid-based monomer include the same unsaturated carboxylic acid-based monomers as those for the rubber-modified polystyrene-based resin (B), and therefore their description is omitted here.

[0196] For the rubber-modified polystyrene resin (B) and the styrene resin (C) of the present embodiment, the styrene resin (C) is different from the rubber-modified polystyrene resin (B) in that it does not contain rubber-like polymer particles (b2). In other words, the styrene resin (C) (before osmium tetroxide treatment) does not substantially contain toluene-insoluble components. In addition, the styrene resin (C) can be the same polymer composition as the polystyrene resin (b1), or it can be a polymer composition different from the polystyrene resin (b1). It should be noted that, in the case where the styrene resin (C) is the same polymer composition as the polystyrene resin (b1), it is difficult to distinguish the two in the recycled styrene resin composition, but by controlling the styrene monomer units of the overall polymer components (components other than the rubber component) in the recycled styrene resin composition, the composition ratio of the unsaturated carboxylic acid monomer units contained as required, the effects of reducing environmental load, mechanical strength, etc. are exerted.

[0197] [Optional additional ingredients]

[0198] In the present embodiment, at any stage before or after the recycling process when manufacturing the above-mentioned recycled polystyrene resin (A), rubber-modified polystyrene resin (B) or optional components, or at the stage of extrusion processing and molding processing of the recycled styrene resin composition, various additives, such as plasticizers such as liquid paraffin, ultraviolet absorbers, light stabilizers, hindered phenol antioxidants, phosphorus-containing antioxidants, sulfur-containing antioxidants and other antioxidants, lubricants, antistatic agents, flame retardants, various dyes or pigments, inorganic crystal nucleating agents (metal oxides such as titanium oxide and tin oxide), organic crystal nucleating agents, fluorescent whitening agents, light diffusers, and selective wavelength absorbers can be added as needed within the scope that does not impair the purpose of the present invention.

[0199] The recycled styrene-based resin composition of the present embodiment preferably contains one or two or more selected from the group consisting of an antioxidant, a pigment, a flame retardant, an additive, a mineral oil, a vegetable oil, and a lubricant.

[0200] The light stabilizer of this embodiment itself has no ultraviolet absorption ability, but preferably has the function of capturing light free radicals generated by the recycled styrene resin composition absorbing ultraviolet rays and rendering them harmless, thereby preventing the composition from being degraded and colored by free radicals. The light stabilizer can be used alone or in combination of two or more, and by using the ultraviolet absorber and / or antioxidant described later, a higher light resistance effect can be exerted.

[0201] Examples of the light stabilizer of the present embodiment include di(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, di(1-undecanyloxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate, tetrakis(2,2,6,6-tetramethyl-4-piperidinyl) butane-1,2,3,4-tetracarboxylate, di(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, N,N'-bis-(2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine, and di(1,2,2,6,6-pentamethyl-4-piperidinyl) butyl(3,5-di-tert-butyl-4-hydroxybenzyl)malonate. Specific product names include ADK STAB LA-52, ADK STAB LA-57, and ADK STAB manufactured by ADK CORPORATION. LA-63P, ADK STAB LA-68, ADK STAB LA-72, ADKSTAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-81; JF-90G, JF-95 manufactured by Johoku Chemical Co., Ltd.; Chimassorb 2020FDL, Chimassorb 944FDL, Tinuvin 622SF manufactured by BASF Japan K.K.

[0202] The ultraviolet absorber of this embodiment has the function of absorbing ultraviolet rays to be absorbed by the recycled styrene resin composition instead of the recycled styrene resin composition and converting it into heat or chemical energy, thereby suppressing the generation of photoradicals caused by ultraviolet absorption of the styrene resin composition and suppressing the degradation and coloration of the resin.

[0203] As the preferable ultraviolet absorber of this embodiment, for example, benzotriazole compounds, triazine compounds, benzophenone compounds, and benzoate compounds are preferable.

[0204] Preferred antioxidants of the present embodiment include, for example, hindered phenol antioxidants such as 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 4,6-bis(octylthiomethyl)-o-cresol (product name, for example, Irganox 1076 manufactured by BASF Japan Co., Ltd.), phosphorus-containing processing heat stabilizers such as tris(2,4-di-tert-butylphenyl) phosphite (product name, for example, Irgafos 168 manufactured by BASF Japan Co., Ltd.), etc. These stabilizers can be used alone or in combination of two or more as appropriate. There is no particular restriction on the timing of addition, which can be any of the polymerization process or the devolatilization process. In addition, the stabilizer can also be mixed in the product using mechanical devices such as extruders and mixers.

[0205] Relative to the total amount of the recycled styrene resin composition, the content of each of the light stabilizer, ultraviolet absorber and antioxidant of the present embodiment is 0.001% by mass to 2.0% by mass, and as the upper limit, it is preferably 1.8% by mass or less, 1.6% by mass or less, 1.4% by mass or less, 1.2% by mass or less, 1.0% by mass or less, 0.8% by mass or less, 0.7% by mass or less, and as the lower limit, it is preferably 0.005% by mass or more, 0.010% by mass or more, 0.021% by mass or more, 0.051% by mass or more, 0.061% by mass or more, 0.071% by mass or more, 0.079% by mass or more, 0.089% by mass or more, 0.12% by mass or more, 0.17% by mass or more. As the content, it can be selected by any combination of the above upper limit and lower limit.

[0206] The recycled styrene resin composition of the present invention may also contain a metal or a metal oxide as an inorganic crystal nucleating agent. In the recycled styrene resin composition of the present embodiment, relative to the total amount 100 mass % of the recycled styrene resin composition, the content of the metal oxide (such as titanium dioxide) is preferably 0.07 mass % or more and 5.5 mass % or less, more preferably 0.65 mass % or more and 3.8 mass % or less, more preferably 1.2 mass % or more and 3 mass % or less. In addition, as another mode, preferably 1.1 mass % or more and 2.8 mass % or less. As another mode, more preferably 0.2 mass % or more and 0.9 mass % or less.

[0207] It should be noted that, relative to 100 mass % of the recycled styrene resin composition, the various additives in the recycled styrene resin composition of the present embodiment are preferably 10.0 mass % or less, more preferably 5.5 mass % or less, further preferably 2.9 mass % or less, further preferably 1.5 mass % or less, and particularly preferably 0.9 mass % or less.

[0208] [Physical properties of recycled styrene resin composition]

[0209] Hereinafter, preferred physical properties of the recycled styrene-based resin composition in the present embodiment will be described.

[0210] <Vicat softening temperature>

[0211] In the present embodiment, the Vicat softening temperature of the recycled styrene resin composition is preferably 88° C. or higher, more preferably 91° C. or higher, and further preferably 93° C. or higher. By having the Vicat softening temperature of 88° C. or higher, a molded product having excellent heat resistance can be obtained. The Vicat softening temperature in this specification is measured under the conditions of a load of 5 kg and a heating rate of 50° C. / hour according to ISO 306.

[0212] <Simply supported beam impact strength>

[0213] The recycled styrene resin composition of this embodiment preferably has a Charpy impact strength of 5 kJ / m 2 More preferably 7 kJ / m 2 ~20kJ / m 2 When the simply supported beam impact strength is less than 5kJ / m 2 It should be noted that in the present disclosure, the simply supported beam impact strength is a value measured according to ISO179.

[0214] The melt mass flow rate of the recycled styrene resin composition of the present embodiment is preferably 1.5 g / 10 minutes or more, more preferably 2 g / 10 minutes to 18 g / 10 minutes. If the melt mass flow rate is 1.5 g / 10 minutes or more, the formability during extrusion molding and vacuum molding is good. The above-mentioned melt mass flow rate can be achieved by adjusting the melt mass flow rate of each component (A) to (C) and the mixing ratio of these resins. It should be noted that in the present disclosure, the melt mass flow rate is a value measured under the conditions of a temperature of 200°C and 5.00 kg according to ISO 1133.

[0215] In the present embodiment, as with the above-mentioned polymer component, the weight average molecular weight (Mw) of the recycled styrene resin composition before osmium tetroxide treatment is preferably 100,000 to 350,000, more preferably 100,000 to 300,000, further preferably 110,000 to 280,000, further preferably 115,000 to 250,000, and particularly preferably 120,000 to 230,000. When the weight average molecular weight is 100,000 to 350,000, a resin having excellent practicality of a balance between impact strength and fluidity can be obtained. It should be noted that the weight average molecular weight can be measured by standard polystyrene conversion using gel permeation chromatography.

[0216] [Method for producing recycled styrene resin composition]

[0217] In the present embodiment, in the method for producing a recycled styrene resin composition, a recycled polystyrene resin (A), a rubber-modified polystyrene resin (B), and optional components added as needed are prepared. Furthermore, the method for blending, melting, kneading, and granulating the recycled polystyrene resin (A), the rubber-modified polystyrene resin (B), and the optional components added as needed is not particularly limited, and the method commonly used in the production of ordinary styrene resins can be used.

[0218] For example, the above-mentioned components after being mixed (mixed) by a drum, a Henschel mixer, etc. are melted and kneaded using a Banbury mixer, a single-screw extruder, a twin-screw extruder, a kneader, etc., and a process of sieving them by a mesh through a screen is performed, and granulation is performed using a rotary cutter, a fan blade cutter, etc., thereby obtaining a recycled styrene resin composition. The resin temperature during melting and kneading is preferably 180°C to 240°C. In order to adjust to the target resin temperature, the barrel temperature of the extruder, etc. is preferably set to a temperature 10°C to 20°C lower than the resin temperature. When the resin temperature is less than 180°C, mixing is insufficient, which is not preferred. On the other hand, when the resin temperature is greater than 240°C, thermal decomposition of the resin occurs, which is not preferred.

[0219] (Preferred embodiment of the method for producing a recycled styrene resin composition)

[0220] The preferred manufacturing method of this embodiment preferably has the following steps:

[0221] A step (I) of preparing a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) contains rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase; and

[0222] A step (II) of melt-kneading the recycled polystyrene resin (A) and the rubber-modified polystyrene resin (B).

[0223] Thereby, a recycled styrene-based resin composition which reduces environmental load, suppresses reduction in mechanical strength, and exhibits excellent appearance can be easily produced.

[0224] Hereinafter, the above step (I) and the above step (II) will be described in detail.

[0225] <Step (I)>

[0226] Step (I) is a preparation step of preparing a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B) as raw materials for the recycled styrene resin composition of the present disclosure.

[0227] Therefore, as the preparation step, it is preferred to have a step (IA) of preparing a polystyrene resin (A) for recycling and a step (IB) of preparing a rubber-modified polystyrene resin (B). Thus, the recycled polystyrene resin (A) and / or the rubber-modified polystyrene resin (B) are used in the step (II) described later, depending on the compounds and properties contained in the recycled polystyrene resin (A) and / or the rubber-modified polystyrene resin (B).

[0228] When the styrene-based resin (C) not containing rubber-like polymer particles is used as a raw material for the recycled styrene-based resin composition, the preparation step may further include a step (IC) of preparing the styrene-based resin (C) not containing rubber-like polymer particles.

[0229] <<Process (IA)>>

[0230] As described above, the recycled polystyrene resin (A) of this embodiment contains the toluene-insoluble component (1) treated with osmium tetroxide and the polymer matrix part (a1) of the recycled polystyrene resin (A). In addition, the recycled polystyrene resin (A) may contain rubber-like polymer particles (a2).

[0231] Therefore, as the form of the polystyrene-based resin (A) to be recycled, the following forms (i) and (ii) can be mentioned.

[0232] (i) the recycled polystyrene resin (A) contains a polymer matrix portion (a1) and a toluene-insoluble component (1) treated with osmium tetroxide, and 99% by mass or more of the total amount of the recycled polystyrene resin (A) is occupied by the polymer matrix portion (a1) and the toluene-insoluble component (1) treated with osmium tetroxide (e.g., polystyrene containing the toluene-insoluble component (1) treated with osmium tetroxide, styrene copolymer resin containing the toluene-insoluble component (1) treated with osmium tetroxide)

[0233] (ii) the recycled polystyrene resin (A) comprises a polymer matrix portion (a1), rubber-like polymer particles (a2) and a toluene-insoluble component (1) treated with osmium tetroxide, and 99% by mass or more of the total amount of the recycled polystyrene resin (A) is occupied by the polymer matrix portion (a1), the rubber-like polymer particles (a2) and the toluene-insoluble component (1) treated with osmium tetroxide (e.g., a rubber-modified polystyrene resin containing the toluene-insoluble component (1) treated with osmium tetroxide)

[0234] When the recycled polystyrene resin (A) is of the form (i) above, the step (IA) is preferably a step (D1) of determining the content of the toluene-insoluble component (1) after the osmium tetroxide treatment contained in the recycled polystyrene resin (A) and the weight average molecular weight of the polymer matrix part (a1).

[0235] On the other hand, when the recycled polystyrene resin (A) is of the form (ii) above, the step (IA) is preferably a step (D2) of determining the content of the rubber-like polymer particles (a2) contained in the recycled polystyrene resin (A), the content of the toluene-insoluble component (1) after the osmium tetroxide treatment, and the weight average molecular weight of the polymer matrix part (a1).

[0236] Thereby, it is possible to obtain a recycled styrene-based resin composition which reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance.

[0237] At this time, the content of the rubber-like polymer particles (a2) contained in the recycled polystyrene resin (A), the content of the toluene-insoluble component (1) after the osmium tetroxide treatment, and the weight average molecular weight of the polymer matrix part (a1) are preferably within the above ranges.

[0238] <Process (IB)>

[0239] The step (IB) for preparing the rubber-modified polystyrene resin (B) of the present embodiment preferably includes a step (E1) for selecting the content of the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene resin (B) and the weight average molecular weight of the polystyrene resin (b1).

[0240] Thereby, it is possible to obtain a recycled styrene-based resin composition which reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance.

[0241] In this case, the content of the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene-based resin (B) and the weight average molecular weight of the polystyrene-based resin (b1) are preferably within the above-mentioned ranges, respectively.

[0242] <Process (IC)>

[0243] The step (IC) of preparing the styrene-based resin (C) not containing rubber-like polymer particles according to the present embodiment preferably includes a step (E2) of selecting the weight average molecular weight of the styrene-based resin (C) not containing rubber-like polymer particles.

[0244] This can provide a recycled styrene resin composition that reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance. In this case, the weight average molecular weight of the styrene resin (C) is preferably within the above range.

[0245] The preferred step (I) of the present embodiment includes the following steps: a step (D2) of determining the content of the rubber-like polymer particles (a2) contained in the recycled polystyrene resin (A), the content of the toluene-insoluble component (1) after the osmium tetroxide treatment, and the weight average molecular weight of the polymer matrix part (a1), a step (E1) of selecting the content of the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene resin (B) and the weight average molecular weight of the polystyrene resin (b1), and a step (E2) of selecting the weight average molecular weight of the styrene resin (C) that does not contain rubber-like polymer particles.

[0246] Thereby, it is possible to obtain a recycled styrene-based resin composition which reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance.

[0247] Furthermore, the step (I) preferably includes a step (III) of removing particulate matter having a predetermined size or larger (for example, a maximum average particle size of 200 μm or larger).

[0248] <Step (II)>

[0249] The step (II) is a step of melt-kneading the recycled polystyrene resin (A) and the rubber-modified polystyrene resin (B) prepared in the step (I).

[0250] As the conditions for the melt kneading, for example, it is preferred to melt knead the above components after blending (mixing) using a drum, Henschel mixer, etc. using a Banbury mixer, a single screw extruder, a twin screw extruder, a kneader, etc. In addition, the resin temperature during the melt kneading is preferably 180° C. to 240° C.

[0251] It should be noted that the term "melted" as used herein generally refers to a state in which a portion of the recycled polystyrene resin (A) or the rubber-modified polystyrene resin (B) is melted, and does not mean that all components in the system are melted.

[0252] The step (II) of the present embodiment preferably includes a step of determining the blending amounts of the recycled polystyrene resin (A), the rubber-modified polystyrene resin (B), and the optionally blended styrene resin (C) not containing rubber-like polymer particles.

[0253] Specifically, it is preferred that the above-mentioned blending amount be determined so that the obtained recycled styrene-based resin composition satisfies the following (v) to (z).

[0254] (v) Relative to the total amount of the obtained recycled styrene resin composition, the content of the polymer component including the polymer matrix part (a1) of the recycled polystyrene resin (A), the polystyrene resin (b1) of the rubber-modified polystyrene resin (B) and the styrene resin (C) not containing rubber-like polymer particles is controlled within the range of greater than or equal to 64 mass % and less than 90 mass %.

[0255] (x) Relative to the total amount of the obtained recycled styrene resin composition, the content of the rubber component containing the rubber-like polymer particles (a2) and the rubber-like polymer particles (b2) is controlled within the range of greater than or equal to 9 mass % and less than 30 mass %, preferably greater than or equal to 10 mass % and less than 28 mass %.

[0256] (y) The content of the toluene-insoluble component (1) after the osmium tetroxide treatment is controlled within a range of 0.1% to 6% by mass, preferably within a range of 1% to 6% by mass, based on the total amount of the obtained recycled styrene-based resin composition.

[0257] (z) The weight average molecular weight (Mw) of the entire polymer component is controlled within the range of 100,000 to 350,000.

[0258] Thereby, it is possible to obtain a recycled styrene-based resin composition which reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance.

[0259] Step (II) of the present embodiment preferably includes a step (G), wherein the melt kneading conditions are adjusted so that the particle size distribution (μm) of the DMF-insoluble component in the recycled styrene resin composition (= the dispersoid in the composition dispersion obtained by dissolving and dispersing the recycled styrene resin composition in N,N-dimethylformamide) satisfies the following formula.

[0260] 0.00<(|d84%-d16%|) / 2<2.00

[0261] (d84% represents the cumulative value 84% diameter in the integrated distribution curve of particle size, and d16% represents the cumulative value 16% diameter in the integrated distribution curve of particle size.)

[0262] Thereby, it is possible to obtain a recycled styrene-based resin composition which reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance.

[0263] Furthermore, the step (II) preferably includes a step (III) of removing particulate matter having a predetermined size or larger.

[0264] <Step (III)>

[0265] The step (III) is a step for removing impurities contained in the recycled polystyrene resin (A), and is preferably performed during the step (I) or the step (II), or after the step (I) or the step (II).

[0266] Thereby, it is possible to obtain a recycled styrene-based resin composition which reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance.

[0267] For example, the above-mentioned step (III) is a step of separating particles smaller than a specified size after mixing the recycled polystyrene resin (A), the rubber-modified polystyrene resin (B) and the styrene resin (C) not containing rubber-like polymer particles as required, preferably after mixing the raw materials and during the melting of the raw materials. In other words, it can be a step of removing the toluene-insoluble component (1) after the osmium tetroxide treatment of a specified amount or more.

[0268] Similarly, for example, the step (III) of separating particulates smaller than a predetermined size may be performed after the step (D1) or the step (D2) and before the step (II).

[0269] The step (III) may specifically include a step of screening using one or more selected from the group consisting of a filter and a screen. For example, the step may be a step of passing the molten raw material through a filter and / or a screen.

[0270] Thus, it is possible to reduce the inclusions of a predetermined size or more contained in the recycled polystyrene resin (A). In addition, the melting of the raw material can be carried out, for example, by being put into an extruder. Moreover, the passing through the filter and the screen can be carried out by arranging a polymer filter and / or a screen near the outlet or inlet of the extruder.

[0271] The filter is a filter for filtering the polymer component of the molten raw material, and specifically, a leaf disk filter, a candle filter, or a bag filter can be cited. Moreover, the lower limit of the average pore size of the filter is preferably 10 μm or more, more preferably 30 μm or more, and the upper limit of the average pore size of the filter is preferably 200 μm or less, more preferably 180 μm or less.

[0272] The mesh may be a copper mesh, a SUS (stainless steel) mesh, or the like. The lower limit of the mesh size of the mesh is preferably 94 μm or more, more preferably 112 μm or more, further preferably 134 μm or more, and further preferably 140 μm or more. In addition, the mesh size of the mesh is preferably 198 μm or less, more preferably 164 μm or less, further preferably 132 μm or less, and further preferably 109 μm or less.

[0273] The upper limit and the lower limit may be combined arbitrarily. For example, the sieve may be 80 mesh (about 198 μm to about 140 μm), 100 mesh (about 164 μm to about 134 μm), 120 mesh (132 μm to 112 μm) or 150 mesh (109 μm to 94 μm).

[0274] By setting the lower limit of the average pore size of the filter or the mesh size of the screen to the above value, excessive resin pressure will not be generated, so there is a tendency to improve productivity. Similarly, by setting the average pore size of the filter or the mesh size of the screen to the above value, there is a tendency to be able to remove finer impurities.

[0275] In the present embodiment, for passing through the filter and / or the screen, it is possible to pass through only one of the filter and the screen, or both. In addition, it is possible to pass through only the filter or the screen multiple times. In addition, it is also possible to pass through their combination.

[0276] In the present embodiment, by using the above-mentioned production method, it is shown that the obtained recycled styrene-based resin composition tends to have the following properties.

[0277] The particle size distribution (μm) of the DMF-insoluble component in the recycled styrene-based resin composition (=dispersoid in a composition dispersion obtained by dissolving and dispersing the recycled styrene-based resin composition in N,N-dimethylformamide) satisfies the following formula.

[0278] 0.00<(|d84%-d16%|) / 2<2.00

[0279] (d84% represents the cumulative value 84% diameter in the integrated distribution curve of particle size, and d16% represents the cumulative value 16% diameter in the integrated distribution curve of particle size.)

[0280] (Particularly preferred method for producing a recycled styrene resin composition)

[0281] The method for producing a recycled styrene resin composition of the present embodiment is a method for producing a recycled styrene resin composition by melt-kneading a recycled polystyrene resin (A), a rubber-modified polystyrene resin (B), and a styrene resin (C) used as an optional component.

[0282] The recycled polystyrene resin (A) contains a polymer matrix part (a1), rubber-like polymer particles (a2) and a toluene-insoluble component (1) treated with osmium tetroxide.

[0283] The rubber-modified polystyrene resin (B) comprises a polymer matrix phase composed of a polystyrene resin (b1) and a domain phase composed of rubber-like polymer particles (b2), wherein:

[0284] The method for producing a recycled styrene resin composition comprises steps (D2) and (E) and further comprises step (F).

[0285] In step (D2), the total amount of the rubber-like polymer particles (a2) and the toluene-insoluble component (1) after the osmium tetroxide treatment contained in the recycled polystyrene resin (A) and the weight average molecular weight of the polymer matrix part (a1) are determined;

[0286] In step (E), the content of the rubber-like polymer particles (b2) in the rubber-modified polystyrene resin (B), the weight average molecular weight of the polystyrene resin (b1), and the weight average molecular weight of the styrene resin (C) are selected;

[0287] In step (F), the blending amounts of the recycled polystyrene resin (A), the rubber-modified polystyrene resin (B) and the styrene resin (C) are determined so that the recycled styrene resin composition satisfies the following (v) to (z).

[0288] (v) controlling the content of the polymer component of the polymer matrix part (a1) of the recycled polystyrene resin (A), the polystyrene resin (b1) of the rubber-modified polystyrene resin (B), and the styrene resin (C) not containing rubber-like polymer particles to be within the range of 64% by mass or more and less than 90% by mass, based on the total amount of the obtained recycled styrene resin composition;

[0289] (x) controlling the content of the rubber component including the rubber-like polymer particles (a2) and the rubber-like polymer particles (b2) to be within a range of 9% by mass or more and less than 30% by mass relative to the total amount of the obtained recycled styrene resin composition;

[0290] (y) controlling the content of the toluene-insoluble component (1) after the osmium tetroxide treatment to be within a range of 1% by mass to 6% by mass relative to the total amount of the obtained recycled styrene-based resin composition;

[0291] (z) controlling the weight average molecular weight (Mw) of the entire polymer component to be within the range of 100,000 to 350,000,

[0292] The method for producing a recycled styrene resin composition comprises step (G):

[0293] In step (G), when melt kneading is carried out with the above-determined blending amounts, the melt kneading conditions are adjusted so that the particle size distribution (μm) of the DMF-insoluble component in the recycled styrene resin composition (= the dispersoid in the composition dispersion obtained by dissolving and dispersing the recycled styrene resin composition in N,N-dimethylformamide) satisfies the following formula (1).

[0294]

[0295] (d84% represents the cumulative value 84% diameter in the integrated distribution curve of particle size, and d16% represents the cumulative value 16% diameter in the integrated distribution curve of particle size.)

[0296] Furthermore, it is preferred that the recycled polystyrene resin (A) is contained in an amount of 30% by mass to 65% by mass based on the total amount (100% by mass) of the recycled styrene resin composition.

[0297] Thereby, it is possible to obtain a recycled styrene-based resin composition which reduces environmental load, further suppresses reduction in mechanical strength, and exhibits a more excellent appearance and excellent heat creep resistance.

[0298] [Molding products]

[0299] As the use of the recycled styrene-based resin composition of the present disclosure, it is preferably used for injection blow molding, sheet (including film), injection molding or extrusion molding.

[0300] [box]

[0301] As an example of a molded product obtained by molding the recycled styrene-based resin composition of the present disclosure, a box will be described below.

[0302] The present invention discloses a cartridge which can be attached and detached to an image forming device for forming a multi-color or monochrome image on a recording medium by an electrophotographic method, wherein the cartridge comprises a cartridge body, a photosensitive drum, and a charging device for charging the surface of the photosensitive drum.

[0303] The box body contains a recycled styrene resin composition, which includes a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component after being treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) contains rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase, and relative to the entire recycled styrene resin composition, the toluene-insoluble component after being treated with osmium tetroxide is greater than 0% by mass and less than or equal to 10% by mass.

[0304] The present invention provides a box obtained by using a recycled styrene-based resin composition, which suppresses reduction in mechanical strength and chemical resistance and exhibits excellent appearance and excellent heat-resistant creep characteristics.

[0305] Generally, it is known that a drum box or the like can be loaded and unloaded from the main body casing of an image forming device, and the box contains a toner and a carrier in a developing container, and has a mechanism for conveying the toner and the carrier together in the developing container. On the other hand, a transfer roller is arranged in the main body casing of the image forming device, and the transfer roller transfers the toner supplied to the photosensitive drum to a sheet. Therefore, it is confirmed that heat is generated in the photosensitive drum and the transfer roller, and creep deformation is generated in the box itself or in the engaging member (claw, etc.) or connecting member between the box and other members. In addition, since the amount of creep deformation depends on the stress applied to each member and the ambient temperature, the amount of creep deformation varies according to the material (resin type, metal type) of each member. As a result, a new problem arises that the photosensitive drum is difficult to be stably rotated and driven. However, it is confirmed that by using the recycled styrene resin composition of this embodiment, a box with excellent heat-resistant creep properties can be formed (refer to the examples described later). In addition, in order to reduce the amount of creep deformation, a method is also considered to add reinforcing materials such as metal plates to the box itself or the engaging components (claws, etc.) or connecting components between the box and other components. However, by using the recycled styrene resin composition of this embodiment, it is possible to provide a box with less creep deformation without using reinforcing materials such as metal plates, especially a box with a photosensitive drum.

[0306] The cartridge of this embodiment may be a cartridge that has a developing unit that develops an electrostatic charge image formed on the surface of an image holder into a toner image with toner and is attachable to and detachable from an image forming apparatus. An example of the cartridge of this embodiment is shown below, but the present invention is not limited thereto.

[0307] The box of the present embodiment is preferably a box having a toner housing for accommodating a colorant and / or a box having a photosensitive drum. In other words, the box of the present embodiment may be an integrated box in which a toner housing portion for accommodating a colorant (so-called toner box portion) and a drum portion having a photosensitive drum (so-called drum box portion) are integrated, or may be a separate box in which the toner box (portion) is separated from the drum box (portion). Therefore, the box of the present embodiment includes: a toner box having a toner housing for accommodating a colorant, a drum box having a photosensitive drum, an integrated box having a toner housing portion for accommodating a colorant and a photosensitive drum, and a separate box having the toner box and the drum box that can be loaded and unloaded from the toner box.

[0308] Below, refer to Figure 1 to Figure 3 An example of a drum cartridge 10 including a photosensitive drum, a toner cartridge 2 including a toner case 3 storing toner, and a separate type cartridge will be described.

[0309] Figure 1 is a schematic diagram of a so-called box 1, Figure 1 The cartridge 1 shows a separate cartridge in which a toner cartridge 2 that can be detachably mounted on a drum cartridge 10 is mounted on the drum cartridge 10. The separate cartridge is mounted on the main body housing of the image forming apparatus. In this specification, a cartridge in which the toner cartridge 2 is mounted on the drum cartridge 10 is referred to as a separate cartridge. That is, the separate cartridge includes the drum cartridge 10 and the toner cartridge 2.

[0310] in addition, Figure 2 for Figure 1 A cross-sectional view of the box 1 is shown. And, Figure 3 To show that Figure 1 The diagram of the cartridge 1 is a schematic diagram of a state where the toner cartridge 2 and the drum cartridge 10 are separated.

[0311] The drum cartridge 10 includes a drum cartridge body 7 and a photosensitive drum 5. In addition, the drum cartridge 10 preferably further includes a charging unit 4, a cleaning roller 8, a transfer roller 11, a developing unit 9, and a conveying roller 12. In addition, the toner cartridge 2 can be attached to and detached from the drum cartridge 10 (see Figure 3 ). In addition, the drum cartridge body 7 is a housing that supports the photosensitive drum 5, the charging unit 4, the cleaning roller 8, the transfer roller 11, the conveying roller 12, the developing unit 9, and the toner cartridge 2. The drum cartridge body 7 has a positioning protrusion (not shown) for positioning a bearing (not shown). In addition, the photosensitive drum 5 can rotate relative to the drum shaft extending in the axial direction.

[0312] In the following description, the "axial direction" refers to the direction in which the drum shaft of the photosensitive drum 5 extends. Figure 1 The “transport direction” is the direction from the transport roller 12 toward the transfer roller 11, indicating Figure 1The “transport direction” is the direction from the lower end of the transport roller 12 toward the clamping position where the sheet S such as paper is clamped by the photosensitive drum 5 and the transfer roller 11. In addition, the direction orthogonal to the “axial direction” and the “transport direction” is referred to as the “orthogonal direction”. Figure 1 The Z direction in .

[0313] The charging unit 4 has the function of charging the photosensitive drum 5. As the charging unit 4, a grid-controlled corona type or a corona type or a charging roller can be listed. In addition, the cleaning roller 8 has the function of cleaning the photosensitive drum 5. And the cleaning roller 8 can rotate relative to the cleaning roller shaft extending in the axial direction. The cleaning roller 8 is opposite to the surface of the photosensitive drum 5, and the cleaning roller 8 is located on the downstream side of the conveying direction of the photosensitive drum 5.

[0314] The transfer roller 11 has a function of transferring the toner supplied to the photosensitive drum 5 from the photosensitive drum 5 to the sheet S. The transfer roller 11 is rotatable relative to a transfer roller shaft extending in the axial direction. The transfer roller 11 is opposite to the surface of the photosensitive drum 5 and is located on the other side ( Figure 1 The transfer roller 11 can convey the sheet S by sandwiching the sheet S between the transfer roller 11 and the photosensitive drum 5.

[0315] When the drum cartridge 10 is installed in the main body housing of the image forming apparatus, the conveying roller 12 contacts with the main body roller of the image forming apparatus and rotates therefrom, and has the function of conveying the sheet S together with the main body roller. The conveying roller 12 is rotatable relative to the conveying roller shaft extending in the axial direction. The conveying roller 12 is located at a position separated by a predetermined distance from the upstream side of the photosensitive drum 5 in the conveying direction.

[0316] The drum cartridge 10 may further include a drum gear as needed. The driving force input from the drum gear can be transmitted to the cleaning roller 8 and the transfer roller 11 in addition to the photosensitive drum 5 through the gear train.

[0317] The developing unit 9 is located between the conveying roller 12 and the photosensitive drum 5 in the conveying direction. The developing unit 9 has a magnetic roller 6, a blade, a blade holder, a developing container, and a storage container. And, the magnetic roller 6 is a roller that supplies toner to the photosensitive drum 5. In addition, the magnetic roller 6 can rotate relative to the magnetic roller shaft extending in the axial direction. And, the magnetic roller 6 is opposite to the surface of the photosensitive drum 5 and is located on the upstream side of the conveying direction of the photosensitive drum 5. The magnetic roller 6 is separated from the surface of the photosensitive drum 5.

[0318] The developing container is a container for containing a toner (not shown) and a carrier (not shown) to be supplied to the magnetic roller 6. The carrier may be a magnetic body. In addition, an example of the carrier is iron powder. The developing container is supplemented with the toner (not shown) contained in the toner box 2 (or inside the toner housing 3). It should be noted that the carrier may be a magnetic body other than iron powder.

[0319] The toner cartridge 2 may further include a toner coupling. The toner coupling is located at one end of the axial side. The toner coupling is a portion that inputs a driving force from the device body of the image forming device to the toner cartridge 2. The driving force input from the toner coupling is transmitted to the agitator and the like through a gear train.

[0320] In the above embodiment, the separate type cartridge in which the toner cartridge 2 is mounted on the drum cartridge 10 is described, but the cartridge 1 of the present disclosure is not limited thereto. For example, it is also possible to apply to a drum cartridge 10 of a type in which the toner cartridge 2 is not mounted, or an integrated type cartridge in which the toner cartridge 2 or a member contained in the toner cartridge 2 is contained in the drum cartridge 10.

[0321] In the above embodiment, a laser printer is described as an example of an image forming apparatus, but the present disclosure is not limited thereto and can be applied to other image forming apparatuses such as inkjet printers, copiers, multifunction peripherals, and the like.

[0322] Example

[0323] Next, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to these examples. The analysis and evaluation methods of the resins and molded articles in the examples and comparative examples are as follows.

[0324] [Evaluation of properties of each resin and resin composition]

[0325] (1) Determination of weight average molecular weight

[0326] The weight average molecular weight (Mw) of each resin and resin composition produced in Examples and Comparative Examples was measured using gel permeation chromatography (GPC) under the following conditions.

[0327] Measuring instrument: HLC-8220 manufactured by Tosoh Corporation

[0328] Separation column: Two TSK gel Super HZM-H (inner diameter 4.6 mm) manufactured by Tosoh Corporation were connected in series.

[0329] Guard column: TSK guard column Super HZ-H manufactured by Tosoh Corporation

[0330] Determination solvent: tetrahydrofuran (THF)

[0331] Sample concentration: 5 mg of a measurement sample was dissolved in 10 mL of a solvent and filtered using a 0.45 μm filter.

[0332] Injection volume: 10 μL

[0333] Measurement temperature: 40℃

[0334] Flow rate: 0.35mL / min

[0335] Detector: Differential Refractometer

[0336] Eleven types of TSK standard polystyrenes (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, and A-5000) manufactured by Tosoh Corporation were used to prepare the calibration curve. The calibration curve was prepared using a first-order linear approximation.

[0337] (2) Determination of melt flow rate (MFR)

[0338] The melt mass flow rate (g / 10 min) of each resin and resin composition produced in Examples and Comparative Examples was measured under the conditions of 200° C. and a load of 49 N in accordance with ISO1133.

[0339] (3) Determination of Vicat softening temperature

[0340] The Vicat softening temperature of each resin and resin composition produced in Examples and Comparative Examples was measured in accordance with ISO 306. The load was set to 50 N, and the heating rate was set to 50° C. / hour.

[0341] (4) Calculation of the Content (mass %) of Each Monomer Unit of Styrene-Based Monomer Unit, (Meth) Acrylic Acid Ester Monomer Unit, and (Meth) Acrylic Acid Monomer Unit

[0342] (NMR measurement)

[0343] By using proton nuclear magnetic resonance ( 1 The resin composition was quantified by the integral ratio of the spectrum measured by H-NMR (NMR) instrument.

[0344] Sample preparation: 30 mg of resin pellets were dissolved in 0.75 ml of d6-DMSO by heating at 60°C for 6 hours.

[0345] Measuring instrument: JNM ECA-500 manufactured by JEOL Ltd.

[0346] Measurement conditions: Measurement temperature 25°C, observation nucleus 1H, accumulation times 64 times, repetition time 11 seconds

[0347] (NMR spectrum assignment)

[0348] The attribution of the spectrum measured in the deuterated solvent of DMSO is as follows: the peaks of 0.5ppm to 1.5ppm are hydrogen of the α-methyl of methacrylic acid, methyl methacrylate and six-membered ring anhydride, the peaks of 1.6ppm to 2.1ppm are hydrogen of the methylene of the polymer main chain, the peak of 3.5ppm is hydrogen of the carboxylate (-COOCH3) of methyl methacrylate, and the peak of 12.4ppm is hydrogen of the carboxylic acid of methacrylic acid. In addition, the peaks of 6.5ppm to 7.5ppm are hydrogen of the aromatic ring of styrene. It should be noted that the resin of the present embodiment is generally difficult to quantify by the present determination method because the content of the six-membered ring anhydride is small.

[0349] (5) Determination of the content of each monomer unit

[0350] The content of each monomer unit contained in the resin composition prepared in Examples and Comparative Examples was measured by thermal decomposition GC / MS under the following conditions.

[0351] <Measurement conditions>

[0352] Thermal decomposition unit

[0353] Equipment: PY-3030D manufactured by Frontier Lab

[0354] Heating furnace temperature: 600℃

[0355] Boundary temperature: 300℃

[0356] GC / MS

[0357] Equipment: GCMS-GP2020NX manufactured by Shimadzu Corporation

[0358] Column: Ultra Alloy-5

[0359] (Length 30m, film thickness 0.25μm, diameter 0.250mmφ)

[0360] Column temperature: maintain at 50°C for 5 minutes, increase the temperature at 10°C / min,

[0361] The temperature was raised from 100° C. at a rate of 7° C. / min and maintained at 300° C. for 10 minutes.

[0362] Inlet temperature: 300°C

[0363] Detector temperature: 300°C

[0364] Split ratio: 1 / 300

[0365] Carrier gas: Helium

[0366] Detection method: Mass spectrometer (MSD)

[0367] Sample amount: 50 μg

[0368] Detection mode: Scan mode or SIM mode

[0369] It should be noted that, in order to avoid peak overlap and saturation of peak intensity when detecting each monomer peak, pretreatment such as sample dilution rate, the column used, and detection conditions may be appropriately adjusted.

[0370] (6) Measurement of rubber polymer particles

[0371] The recycled styrene resin composition of the embodiment described later and the resin composition of the comparative example are dyed with osmium tetroxide, and then 5 ultrathin sections with a thickness of 100nm are made, and 5 bright field images (multiple 10000 times) are obtained respectively using a transmission electron microscope. Then, 5 respective bright field images are added up, and the area average particle diameter is calculated by the following formula (N1), which is used as the weight average diameter of the rubber-like polymer particles. The above analysis is implemented as described below using image analysis software ImageJ (manufactured by the National Institute of Health of the United States). The image obtained is binarized by the method of Otsu (Otsu method), and the white part (equivalent to the polymer matrix phase) except the rubber-like polymer particles is painted with color. The rubber-like polymer particles adjacent to each other are divided by Watershed processing, and the area of ​​the rubber-like polymer particles is calculated, which is then converted into the equivalent circle diameter. The histogram and the average value of the number basis are derived from the numerical group of the equivalent circle diameter obtained. In addition, the device etc. used are described below.

[0372] Weight average diameter = ΣniDri 4 / ΣniDri 3 (N1)

[0373] (In the above formula (N1), ni is the number of rubber-like polymer particles having a particle size Dri, and the particle size Dri is the particle size calculated as an equivalent circle diameter from the area of ​​the particles in the bright field image.)

[0374] Ultrathin sectioner: UC7 / Leica

[0375] Transmission electron microscope: HT7700 / Hitachi High-Technologies Corporation

[0376] (7) Determination of simply supported beam impact strength

[0377] For the test piece used in the measurement of the simply supported beam impact strength, a strip of a predetermined size cut from the central parallel portion of a 1A dumbbell-shaped test piece produced by the method described in the "Method for producing ISO dumbbell-shaped test piece" column described later was used. The simply supported beam impact strength (kJ / m 2 ).

[0378] (8) Determination of tensile yield stress

[0379] As the test piece used for the measurement of the tensile yield stress, a 1A type dumbbell-shaped test piece was used, which was produced by the method described in the column "Method for producing ISO dumbbell-shaped test piece" described later using each resin composition produced in the Examples and Comparative Examples. The tensile yield stress (MPa) of the test piece was measured according to ISO527-1.

[0380] (9) Determination of nominal tensile strain at break

[0381] Injection-molded sheets were prepared from each resin composition prepared in Examples and Comparative Examples at 220° C. in accordance with JIS K 7152, and the tensile break nominal strain (%) was measured in accordance with JIS K 7161 and ISO 527-1.

[0382] (10) Determination of flexural modulus

[0383] The various resin compositions produced in the examples and comparative examples were injection molded into ISO type 1A dumbbell test pieces. Strips of a predetermined size were cut out from the central parallel portion of the dumbbell test pieces. The flexural modulus (MPa) was measured using the strips in accordance with ISO178.

[0384] (11) Determination of load deflection temperature

[0385] ISO type 1A dumbbell test pieces were injection molded from various resin compositions produced in the examples and comparative examples, and strips of a specified size were cut from the central parallel portion of the dumbbell test pieces. The deflection temperature under load (unit: ° C) was measured using the strips under a load of 1.8 MPa according to ISO75-1 and ISO75-2. In addition, the "AUTO HDT Tester 6A-2V" manufactured by Toyo Seiki Co., Ltd. was used to measure the deflection temperature under load.

[0386] (12) Determination of chemical resistance (property retention rate)

[0387] In order to evaluate the chemical resistance of various resin compositions produced in Examples and Comparative Examples, a predetermined grease (MOLYKOTE EM-50LP: DuPont Toray Specialty Materials Co., Ltd.) was applied to the central parallel portion of an ISO type 1A dumbbell-shaped test piece, and an aging treatment was performed in a hot air circulation oven at 60°C for 168 hours. The grease was wiped off with a waste cloth, and then the appearance was confirmed, the tensile break strain was measured, and compared with the initial value, and the retention rate (%) was calculated.

[0388] Chemical resistance (property retention rate) (%) = (tensile strain at break of sample after grease application and 168-hour aging treatment) ÷ (tensile strain at break of sample without grease application and 168-hour aging treatment)

[0389] (13) Determination of thermal creep resistance

[0390] A strip of a specified size was cut from the central parallel portion of the 1A dumbbell-shaped test piece, and the strip was used to perform a bending creep test based on a three-point load according to ISO899-2. The conditions were set as follows: the atmosphere temperature was 60°C, the load was 29.4N, and the strain (mm) after a certain period of time (100 hours) was evaluated.

[0391] (14) Appearance

[0392] A three-stage plate of 120 mm × 50 mm with thicknesses of 2.5 mm, 2.0 mm, and 1.0 mm was molded using an injection molding machine. A flat surface (40 × 50 mm) with a thickness of 2.0 mm in the center of the plate was used to observe black spot foreign matter and measure the 60° glossiness. Black spots were sized according to the inclusion measurement chart (JIS P 8208) and the number of black spots was investigated.

[0393] If all the black spots observed are 0.1 mm 2 If it is less than 0.1 mm, it is judged as 0. 2 And less than or equal to 0.5mm 2 The number of black spots is less than 20 and larger than 0.5 mm 2 And less than or equal to 0.7mm 2 If there are 2 or less black dots, it is judged as △, otherwise it is judged as ×.

[0394] The glossiness was measured using a gloss meter GM26D (Murakami Color Research Laboratory Co., Ltd.) at 60° specular gloss in accordance with JIS Z 8741. A glossiness of 35 or less was judged as △, and a glossiness of 36 or more was judged as 0 (pass).

[0395] (15) Laser diffraction determination

[0396] 20 mg of the recycled styrene resin composition of the embodiment and the resin composition of the comparative example and 20 mL of N, N-dimethylformamide were added to a disposable cup made of polypropylene, and ultrasonic vibration was applied for 15 minutes to dissolve and disperse it. A portion of the turbid liquid of the sample was extracted under vibration and placed in a sample pool for determination. While stirring with a rotor, a laser diffraction particle size measuring device (manufactured by Horiba, Ltd., LA-960V2) was used to obtain the particle size (d84%, d50%, d16%) and integral distribution curve of the dispersoid of the N, N-dimethylformamide solution containing the recycled styrene resin composition or the resin composition. At this time, the refractive index of the sample was set to 1.6-0.00i, and the refractive index of the solvent was set to 1.428. In this embodiment, a volume-based particle size distribution was used.

[0397] For example, the volume-based particle size distribution (d 84 %-d 16 %) is 1.18, the average particle size d 50 On the other hand, the particle size distribution (d 84 %-d 16 %) is 0.90, the average particle size d 50 In other examples, the average particle size based on the number of particles also tends to become smaller and the distribution to become narrower.

[0398] (16) Determination of weld strength retention (bending strength)

[0399] Using the recycled styrene resin composition obtained in the examples and comparative examples, the molten resin of the recycled styrene resin composition was flowed from both ends of the length direction of the shape of 125 mm in length, 13 mm in width, and 3.2 mm in thickness, and the injection molding machine (PS40E manufactured by Nissin Industry Co., Ltd.) was used to form a mold in the middle of the length direction (molding temperature 220°C, mold temperature 45°C, injection pressure: 7.5 MPa (50%), injection speed: 215 cm / min (50%), constant speed and constant pressure molding), thereby obtaining a test piece. The distance between the chucks was set to 50 mm, the tensile speed was set to 1.5 mm / min, and in addition, the tensile strength was obtained by the method according to ISO 527, and then the weld strength retention rate was calculated by the following formula. It should be noted that the measured value adopts the average value of N=5.

[0400] Weld strength retention rate (%) = (bending strength with weld) ÷ (bending strength without weld) × 100

[0401] [Raw materials used in Examples and Comparative Examples]

[0402] The properties of the recycled polystyrene resin (A), the rubber-modified polystyrene resin (B), and the styrene resin (C) used in Examples and Comparative Examples are shown in Table 1. In addition, the additives used in Examples and Comparative Examples are as follows.

[0403] [Table 1-1]

[0404]

[0405] [Table 1-2]

[0406]

[0407] [Table 1-3]

[0408]

[0409] [Table 1-4]

[0410]

[0411] (additive)

[0412] Antioxidant: Octadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl) propionate

[0413] Release agent: zinc stearate

[0414] Plasticizer: Liquid paraffin

[0415] [Examples and Comparative Examples]

[0416] "Method for producing recycled styrene resin composition of Examples 1 to 20"

[0417] The raw materials described in the column [Raw materials used in Examples and Comparative Examples] were prepared. Specifically, the content of the rubbery polymer particles (a2) contained in the recycled polystyrene resins (A1) to (A8), the content of the toluene-insoluble component (1) (= mixed material) after the osmium tetroxide treatment, and the weight average molecular weight of the polymer matrix part (a1) were measured before melt kneading.

[0418] In addition, the content of the rubber-like polymer particles (b2) contained in the rubber-modified polystyrene-based resins (B1) to (B7) and the weight average molecular weight of the polystyrene-based resin (b1) were measured.

[0419] Next, the weight average molecular weight of the new material (C1) was measured. Then, in each example, raw materials were prepared according to the above column [Raw materials used in Examples and Comparative Examples] and the following Tables 2-1 to 2-3 so that the molecular weight of the obtained recycled styrene resin composition, the content of the rubber component, the content of the admixture (toluene insoluble component (1) after osmium tetroxide treatment), and the weight average molecular weight of the polymer component were predetermined values. Then, the weighed raw materials were blended using a rotary drum, and melt-kneaded using a twin-screw extruder (TEM-26SS manufactured by Toshiba Machine Co., Ltd.) at a barrel setting temperature of 220° C. and a screw speed of 200 rpm. The molten resin was passed through a screen provided on the upstream side of a porous plate between the extruder screw tip and the die head, and then extracted from the die head in the form of molten strands. The molten strands were water-cooled and cut using a rotary cutter to obtain pelletized recycled styrene resin compositions of Examples 1 to 20. Then, the physical properties of the styrene-based resin compositions of Examples 1 to 20 were measured and evaluated according to the above-described measuring methods. The results are shown in Tables 2-1 to 2-3.

[0420] It should be noted that, during the above melt kneading, the melt may be passed through a sieve as required so that the volume-based particle size distribution (d 84 %-d 16 %) is less than 2.

[0421] "Method for producing resin compositions of Comparative Examples 1 to 6 and Reference Examples 1 to 4"

[0422] The raw materials were prepared according to the above column [Raw materials used in the examples and comparative examples] and the following Tables 2-4, and then the measured raw materials were mixed using a rotary drum, and melt-kneaded using a twin-screw extruder (TEM-26SS manufactured by Toshiba Machine Co., Ltd.) at a barrel setting temperature of 220°C and a screw speed of 200 rpm, and extracted in the form of molten strands. The molten strands were water-cooled and cut using a rotary cutter to obtain granular resin compositions of Comparative Examples 1 to 6 and Reference Examples 1 to 4. Then, the physical properties of the resin compositions of Comparative Examples 1 to 6 and Reference Examples 1 to 4 were measured and evaluated according to the measurement methods described above. The results are shown in Tables 2-4.

[0423] [Table 2-1]

[0424]

[0425] [Table 2-2]

[0426]

[0427] [Table 2-3]

[0428]

[0429] [Table 2-4]

[0430]

[0431] "Preparation and evaluation of boxes of Examples 21 to 26"

[0432] The box shell (box body) was made using the recycled styrene resin composition manufactured in the above-mentioned embodiment. Specifically, the box shell is a box-shaped shape (size is length 260mm×depth 80mm×height 80mm) obtained by setting the ribs in a lattice shape, and the recycled styrene resin composition manufactured in the embodiment shown in Table 3 was used to form a three-plate mold using a cold runner with two pinpoint gates to make the box shell.

[0433] Then, the obtained cartridge case was subjected to practical creep evaluation under the following conditions. The results are shown in Table 3.

[0434] <Evaluation of practical creep properties>

[0435] Fix the positioning pin inside the box body to the fixture. Then, put it into a 60°C oven with a load of 4.6kg (iron weight with a diameter of 50mm×height of 300mm) applied to the central part of the box body in the longitudinal direction, and measure the deformation (mm) of the central part of the box body after 100 hours. As a result, if the deformation of the central part of the box body is within 0.5mm, it is judged as qualified (○), and if the deformation is greater than 0.5mm, it is judged as unqualified (×).

[0436] "Box of Comparative Example 7"

[0437] A cartridge case was produced using the resin composition in the same manner as in Examples 21 to 26. The resin composition used in Comparative Example 7 is shown in Table 3.

[0438] [Table 3]

[0439]

[0440] Description of symbols

[0441] 1 box

[0442] 2 Toner Cartridges

[0443] 3Toner housing

[0444] 4 live units

[0445] 5 Photosensitive drum

[0446] 6 Magnetic rollers

[0447] 7-Drum cartridge body

[0448] 8 Cleaning rollers

[0449] 9Development unit

[0450] 10 drum box

[0451] 11 Transfer roller

[0452] 12 conveyor rollers

Claims

1. A recycled styrene resin composition, comprising a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) comprises a toluene-insoluble component (1) treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) comprises rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase, wherein: The toluene-insoluble component (1) after the osmium tetroxide treatment is greater than 0% by mass and less than or equal to 10% by mass based on the entire recycled styrene-based resin composition.

2. The recycled styrene resin composition according to claim 1, wherein The recycled styrene resin composition comprises: 55% by mass or more and less than 97.9% by mass of a polymer component, wherein the polymer component comprises a polymer matrix portion (a1) of the recycled polystyrene resin (A) and the polystyrene resin (b1); 2.1% to 35% by mass of a rubber component, wherein the rubber component comprises the rubber-like polymer particles (b2); and The recycled polystyrene resin (A) is subjected to osmium tetroxide treatment, and the toluene-insoluble component (1) after osmium tetroxide treatment is greater than 0% by mass and less than or equal to 10% by mass.

3. The recycled styrene resin composition according to claim 1 or 2, wherein The recycled styrene-based resin composition further contains a styrene-based resin (C), and the styrene-based resin (C) does not contain rubber-like polymer particles.

4. The recycled styrene resin composition according to claim 1 or 2, wherein The weight average molecular weight (Mw) of the recycled styrene resin composition is in the range of 100,000 to 350,000.

5. The recycled styrene resin composition according to claim 1 or 2, wherein The average particle size of all rubber-like polymer particles in the recycled styrene-based resin composition is in the range of 1.6 μm to 3.2 μm.

6. The recycled styrene resin composition according to claim 1 or 2, wherein All rubber-like polymer particles in the recycled styrene-based resin composition contain conjugated diene-based monomer units, and the content of the conjugated diene-based monomer units is 2% by mass to 15% by mass based on the entire recycled styrene-based resin composition.

7. The recycled styrene resin composition according to claim 1 or 2, wherein The recycled styrene resin composition contains one or more selected from the group consisting of an antioxidant, a pigment, a flame retardant, an additive, a mineral oil, a vegetable oil and a lubricant.

8. The recycled styrene resin composition according to claim 1, wherein The content of all rubber-like polymer particles in the recycled styrene-based resin composition is 2.1% by mass to 35% by mass based on the entire recycled styrene-based resin composition.

9. A method for producing a recycled styrene resin composition according to claim 1 or 2, wherein: The method for producing the recycled styrene resin composition comprises the following steps: A step (I) of preparing a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) contains rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase; and A step (II) of melt-kneading the recycled polystyrene resin (A) and the rubber-modified polystyrene resin (B).

10. A molded body, wherein The molded article is obtained by molding the recycled styrene-based resin composition according to claim 1 or 2.

11. A cartridge which can be attached to and detached from an image forming device for forming a multi-color or monochrome image on a recording medium by an electrophotographic method, wherein: The cartridge includes a cartridge body, a photosensitive drum, and a charging unit for charging the surface of the photosensitive drum. The box body contains a recycled styrene resin composition, which includes a recycled polystyrene resin (A) and a rubber-modified polystyrene resin (B), wherein the recycled polystyrene resin (A) contains a toluene-insoluble component (1) after being treated with osmium tetroxide, and the rubber-modified polystyrene resin (B) contains rubber-like polymer particles (b2) constituting a domain phase and a polystyrene resin (b1) constituting a polymer matrix phase, and relative to the entire recycled styrene resin composition, the toluene-insoluble component (1) after being treated with osmium tetroxide is greater than 0% by mass and less than or equal to 10% by mass.

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