JP2024025568A - Styrenic resin composition and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a styrenic resin composition or a molding thereof that adequately retains strength after light exposure, without compromising heat resistance or strength.

SOLUTION: A styrenic resin composition includes a styrenic resin (A) and a first component (B). The styrenic resin (A) is a copolymer including a styrenic monomer unit (a1) and a (meth) acrylic acid monomer unit (a2). The first component (B) includes at least one selected from the group consisting of 4-methoxyphenol and hydroquinone. The content of the first component (B) is less than 1 μg per 1 g of the styrenic resin (A).

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to a styrenic resin composition and a molded article formed using the styrenic resin composition.

Styrene-unsaturated carboxylic acid resins, such as styrene-methacrylic acid copolymer resins, have excellent heat resistance, transparency, rigidity, and appearance, and are inexpensive, so they are used as packaging materials for food containers such as lunch boxes and side dishes. It is widely used in foam boards for insulation in homes, diffuser panels for LCD televisions containing a diffusing agent, etc. In particular, styrene-unsaturated carboxylic acid resins used in optical components (e.g., light guide plates, light diffusion plates, etc., optical films, etc.) have problems with transparency or hue. A technique is disclosed in which a predetermined amount of 4-methoxyphenol or hydroquinone is added to (Patent Document 1).

International Publication No. 2022/004508

The hue of the styrene resin composition of Patent Document 1 has been studied. However, it was confirmed that the content of 4-methoxyphenol or hydroquinone in the styrene-based resin composition is relatively high, and that there remains room for improvement regarding the temperature increase of the material due to light exposure or the decrease in strength after light exposure.
An object of the present disclosure is to provide a styrenic resin composition and a molded article thereof that exhibit excellent strength retention after exposure to light without reducing heat resistance and strength.

As a result of intensive research in view of the above problems, the present inventor has found that according to the present invention, the styrene resin (A) includes a styrene resin (A) and a first component (B), and the styrenic resin (A) is A copolymer containing a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2), the component (B) containing 4-methoxyphenol or hydroquinone, and the component (B) containing 4-methoxyphenol or hydroquinone. A styrenic resin composition in which the content of B) is less than 1 μg per 1 g of the styrenic resin (A), which has excellent strength retention after exposure to light without reducing heat resistance and strength, and the use thereof We succeeded in creating a molded product and completed the present invention. That is, the present disclosure is as follows.

[1] Contains a styrenic resin (A) and a first component (B), the styrenic resin (A) contains a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2). ), the first component (B) contains one or more selected from the group consisting of 4-methoxyphenol and hydroquinone, and the first component (B) A styrenic resin composition having a content of less than 1 μg per 1 g of the styrenic resin (A).

[2] In the present embodiment, when the total content of the styrene monomer unit (a1) and the (meth)acrylic acid monomer unit (a2) is 100% by mass, the styrenic monomer unit (a1) and the (meth)acrylic acid monomer unit (a2) are The content of the monomer unit (a1) is 99.9 to 40% by mass, and the content of the (meth)acrylic acid monomer unit (a2) is 0.1 to 60% by mass. , the styrenic resin composition according to [1].

[3] One aspect of the present embodiment is that the (meth)acrylic acid monomer unit (a2) is a methacrylic acid monomer unit (a2-1) and a methacrylic acid ester monomer unit (a2-2). ), and the copolymer contains a methacrylic acid monomer unit (a2-1), in [1] or [2] above. The styrenic resin composition described above.

[4] One aspect of the present embodiment includes a conjugated diene monomer unit (c1) and a (meth)acrylic acid ester monomer unit (c2) relative to the total amount of the styrenic resin composition. The styrenic resin composition according to [1] or [2] above contains core-shell type rubbery polymer particles (C) in an amount of 0.1% by mass or more and 50% by mass or less.

[5] One aspect of the present embodiment is the above-mentioned [1] or [1], which contains 0.1% by mass or more and 50% by mass or less of the impact-resistant styrenic resin (D) based on the total amount of the styrenic resin composition. 2].

[6] One aspect of this embodiment is the above-mentioned [1] or [1], which contains 0.1% by mass or more and 50% by mass or less of (meth)acrylic resin (E) based on the total amount of the styrenic resin composition. 2].

[7] One aspect of the present embodiment is the above-mentioned [1] or [2], which contains 20 μg or less of t-butylcatechol (F) per 1 g of the styrene resin (A) based on the total amount of the styrenic resin composition. ] is the styrenic resin composition described.

[8] One aspect of the present embodiment is the above-mentioned composition containing 0.001% by mass or more and 2.0% by mass or less of a monohydric alcohol (G) having 10 or more carbon atoms based on the total amount of the styrenic resin composition. The styrenic resin composition according to [1] or [2].

[9] In one aspect of the present embodiment, the styrenic resin (A) comprises the styrene monomer (a1), the (meth)acrylic acid monomer unit (a2), and the 4- The styrenic resin composition according to [1] or [2] above uses methoxyphenol and/or the hydroquinone as a reaction raw material.

[10] One aspect of the present embodiment is a molded article made of the styrenic resin composition described in [1] or [2] above.

[11] One aspect of the present embodiment is a light guide made of the styrene resin composition described in [1] or [2] above.

[12] One aspect of the present embodiment is a non-foamed extruded sheet having a thickness of 1 mm or less and made of the styrenic resin composition described in [1] or [2] above.

[13] One aspect of the present embodiment is a foam extrusion sheet made of the styrenic resin composition described in [1] or [2] above.

[14] One aspect of the present embodiment is an injection molded article for use in a vehicle, which is formed by injection molding the styrenic resin composition described in [1] or [2] above.

According to the present disclosure, it is possible to provide a styrenic resin composition used for molded products that exhibits excellent strength retention after exposure to light without reducing heat resistance and strength.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail. Note that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.

[Styrenic resin composition]
A styrenic resin composition according to an embodiment of the present invention includes a styrenic resin (A) and a first component (B). Further, the styrene resin (A) is a copolymer containing a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2). The first component (B) contains one or more selected from the group consisting of 4-methoxyphenol and hydroquinone, and the content of the component (B) is 1 g of the styrene resin (A). less than 1 μg per sample.
Thereby, it is possible to provide a styrenic resin composition that has excellent strength retention after exposure to light without reducing heat resistance and strength.
In addition, the styrene resin composition in this embodiment may optionally include MBS resin (C), HIPS resin (D), (meth)acrylic resin (E), t-butylcatechol (F) and carbon atom number 10. It may contain one or more selected from the above group of monohydric alcohols (G).
Thereby, it is possible to provide a styrenic resin composition that has excellent strength retention after exposure to light without further reducing heat resistance and strength.

"Styrenic resin (A)"
The styrenic resin (A) in this embodiment is a copolymer (hereinafter simply referred to as resin (A)) comprising a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2) as essential components. ), and the styrenic resin (A) may optionally contain other components other than the essential components of the styrene monomer unit (a1) and the (meth)acrylic acid monomer unit (a2). It may further contain a monomer unit (a3).

The content of the resin (A) is preferably 50 to 100% by mass with respect to the total amount (100% by mass) of the styrene resin composition, and the lower limit is 53% by mass or more, 56% by mass or more, 59% by mass or more. More preferably in the order of mass% or more, 62 mass% or more, 65 mass% or more, 69 mass% or more, 70 mass% or more, and the upper limit values are 95 mass% or less, 92 mass% or less, 89 mass% or less, More preferably, the content is 86% by mass or less, 83% by mass or less, 80% by mass or less, 77% by mass or less, 74% by mass or less, and 71% by mass or less. The content of the styrene resin (A) may be any combination of the above upper limit and lower limit.

In particular, by setting the content of the styrene resin (A) to 50% by mass or more, heat resistance can be imparted to the styrenic resin composition.

<Styrenic monomer (a1)>
In the styrenic resin (A) of the present embodiment, the content of the styrenic monomer unit (a1) is 60 to 98% by mass, preferably 70 to 98% by mass, based on the total amount of the styrenic resin (A). It is 97% by weight, more preferably 80-96% by weight, even more preferably 82-95% by weight. If the content of the styrene monomer unit (a1) is less than 60% by mass, fluidity will decrease, and if it is more than 98% by mass, the (meth)acrylic acid monomer unit (a2) described below is desired. Therefore, the effect of improving heat resistance by the (meth)acrylic acid monomer unit (a2) cannot be sufficiently obtained.
Furthermore, in the styrenic resin composition of the present embodiment, the styrenic monomer unit (a1) is preferably contained in an amount of 50 to 97% by mass, preferably 60 to 97% by mass based on the total amount of the styrenic resin composition. The content is 95% by weight, more preferably 70-93% by weight, even more preferably 81-90% by weight. When the content of the styrenic monomer (a1) in the entire composition is within the above range, a styrenic resin composition with excellent processability can be obtained.

In this embodiment, the styrenic monomer (1) is not particularly limited, but examples include styrene, α-methylstyrene, β-methylstyrene, paramethylstyrene, orthomethylstyrene, metamethylstyrene, chlorostyrene, Examples include bromostyrene. Particularly from an industrial standpoint, styrene and α-methylstyrene are preferred, and styrene is more preferred. As the styrenic monomer (1), these can be used alone or in combination of two or more.
In addition, the "styrenic monomer unit (a1)" in this specification means a repeating unit constituting a polymer in which the styrenic monomer (a1) is polymerized, and the styrenic monomer (a1) ) is a repeating unit (or structural unit) in which a carbon-carbon double bond in the styrenic monomer (a1) becomes a single bond (-C-C-) through a polymerization reaction or a crosslinking reaction. Moreover, other "monomeric units" in this specification have the same meaning.

<(meth)acrylic acid monomer unit (a2)>
In the styrene resin (A) of this embodiment, the (meth)acrylic acid monomer unit (a2) plays a role in improving heat resistance. With respect to the total amount of the styrene resin (A), the content of the (meth)acrylic acid monomer unit (a2) is preferably 2 to 40% by mass, more preferably 3 to 35% by mass, The content is more preferably 5 to 30% by weight, even more preferably 8 to 25% by weight, and most preferably 10 to 20% by weight. If the content of the (meth)acrylic acid monomer unit (a2) is less than 2% by mass, the effect of improving heat resistance is insufficient. In addition, if the content of the (meth)acrylic acid monomer unit (a2) exceeds 40% by mass, processability may decrease due to increased resin viscosity, bubbles may occur during molding due to increased water absorption, and viscosity may increase during manufacturing. This is not preferable because it becomes too high. In particular, by setting the content of the (meth)acrylic acid monomer unit (a2) to 8 to 20% by mass, a styrenic resin composition with an excellent balance between heat resistance and appearance can be obtained.
In addition, the (meth)acrylic acid monomer unit (a2) in this embodiment includes (meth)acrylic acid and its ester, and specifically, the (meth)acrylic acid monomer unit (a2) -1) and (meth)acrylic acid ester monomer unit (a2-2).
Examples of the (meth)acrylic acid monomer (a2-1) in this embodiment include acrylic acid and methacrylic acid.
Examples of the (meth)acrylic acid ester monomer (a2-2) in this embodiment include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylic acid ( (n-butyl), (t-butyl) (meth)acrylate, (isobutyl) (meth)acrylate, cyclohexyl (meth)acrylate, cybenzyl (meth)acrylate, (n-octyl) (meth)acrylate, Examples include (2-ethylhexyl) (meth)acrylate, decyl (meth)acrylate, and stearyl (meth)acrylate. These can be used alone or in combination.

<Other monomers (a3)>
The styrenic resin (A) in this embodiment contains other monomer units (a3) other than the above-mentioned styrene monomer unit (a1) and non-(meth)acrylic acid monomer unit (a2). You may further have it.
That is, in this embodiment, the effect of the invention is obtained if the other monomer unit (a3) is copolymerizable with the styrene monomer (a1) and the (meth)acrylic acid monomer unit (a2). It may be copolymerized with monomers other than the two monomers shown above, without any particular restriction, as long as the properties are not impaired.
For example, other monomers (a3) other than the two monomers shown above include maleic anhydride, maleic acid, fumaric acid, itaconic acid, (meth)acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl fumarate. ester, ethyl fumarate, maleimide, and nuclear-substituted maleimide.
In this embodiment, when the styrenic resin (A) has other monomers (a3), the content of the other monomers (a3) is 20 mass with respect to the total amount of the styrenic resin (A). % or less, more preferably 10% by mass or less, even more preferably 6% by mass or less.

<Characteristics of styrenic resin (A)>
The content of the (meth)acrylic acid monomer unit (a2) in the styrene resin (A) in this embodiment can be determined by neutralization titration described below.
The content of the styrene monomer unit (a1) and other monomer units (a3) can be quantified using a calibration curve created using a resin with known monomer units using pyrolysis GC/MS. .
The melt flow rate at 200°C of the styrenic resin (A) in this embodiment is preferably 0.3 to 3.0, more preferably 0.4 to 2.5, even more preferably 0.5 to 2. 0, more preferably in the range of 0.6 to 1.8. When the melt flow rate is 0.3 or more, it is preferable from the viewpoint of fluidity, and when it is 3.0 or less, it is preferable from the viewpoint of the mechanical strength of the resin. In the present disclosure, the melt flow rate is a value measured at 200° C. and a load of 5 kg (49 N) in accordance with ISO 1133.

The weight average molecular weight (Mw) of the styrenic resin (A) in this embodiment is preferably 100,000 to 400,000, more preferably 120,000 to 320,000, still more preferably 140,000 to 280,000, and even more preferably The range is preferably 160,000 to 240,000, most preferably 170,000 to 210,000. When the weight average molecular weight is from 100,000 to 400,000, a resin with an excellent balance between impact strength and fluidity can be obtained. The weight average molecular weight and number average molecular weight can be measured by gel permeation chromatography in terms of polystyrene standards.

The number average molecular weight (Mn) of the styrenic resin (A) of this embodiment is preferably 40,000 to 150,000, more preferably 50,000 to 120,000, even more preferably 60,000 to 100,000, and most preferably It is preferably in the range of 70,000 to 90,000.

The number average molecular weight (Mz) of the styrenic resin (A) of the present embodiment is preferably 200,000 to 800,000, more preferably 250,000 to 500,000, even more preferably 300,000 to 450,000. .

The Vicat softening temperature of the styrenic resin (A) in this embodiment is preferably 105 to 140°C, more preferably 107 to 135°C, even more preferably 108 to 130°C, even more preferably 115 to 127°C, 120°C. ℃～125℃. By setting the Vicat softening temperature of the styrenic resin (A) to 105°C or higher, the effect of improving the heat resistance of the composition can be obtained, and by setting it to 140°C or lower, it becomes easier to knead with other resins. In particular, by setting the temperature to 120° C. or higher, a styrenic resin composition with excellent heat resistance can be obtained. The method for measuring the Vicat softening temperature in this specification is based on ISO 306, with a load of 5 kg and a heating rate of 50° C./hour.

<Method for producing styrenic resin (A)>
The method for producing the styrenic resin (A) of this embodiment will be described below.
The method for producing the styrenic resin (A) of this embodiment includes a styrene monomer (a1), a (meth)acrylic acid monomer (a2), another monomer (a3), and a solvent. , and additive raw materials such as a polymerization initiator, a chain transfer agent, and a monohydric alcohol (G) having 10 or more carbon atoms, which will be described later and are added as necessary, to prepare a polymerization raw material composition; , a polymerization step in which the polymerization raw materials (each monomer component) in the reaction raw materials are polymerized to produce a polymer, and a liquid phase component consisting of unreacted polymerization raw materials and solvent is removed by devolatilization under high temperature and high vacuum. It is preferable to include a devolatilization step of recovering the liquid.
There are no particular limitations on the polymerization method for the styrene resin (A), but for example, radical polymerization, among which bulk polymerization or solution polymerization can be preferably employed.

In this specification, the reaction raw material refers to a polymerization raw material for styrenic resin (A) (styrene monomer (a1) and (meth)acrylic acid monomer (a2) are essential, and each other monomer is a polymerization solvent, and additive raw materials such as a polymerization initiator, a chain transfer agent, and a monohydric alcohol (G) having 10 or more carbon atoms, which are added as necessary. It is a general term for

In this embodiment, when polymerizing the reaction raw materials to obtain the styrenic resin (A), it is preferable to include a polymerization initiator in the reaction raw materials. As a polymerization initiator, organic peroxides such as 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy)butane, - Peroxyketals such as (butylperoxy)valerate, dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide, diacyl peroxides such as acetyl peroxide and isobutyryl peroxide, and diisopropyl peroxide. Examples include peroxydicarbonates such as carbonate, peroxyesters such as t-butyl peroxyacetate, ketone peroxides such as acetylacetone peroxide, and hydroperoxides such as t-butyl hydroperoxide. From the viewpoint of decomposition rate and polymerization rate, 1,1-bis(t-butylperoxy)cyclohexane is particularly preferred.

In this embodiment, a chain transfer agent can also be used as necessary in the reaction raw material during polymerization of the styrenic resin (A). Examples of chain transfer agents include α-methylstyrene linear dimer, n-dodecylmercaptan, t-dodecylmercaptan, n-octylmercaptan, and the like.

As a method for polymerizing the styrene resin (A), solution polymerization using a polymerization solvent can be adopted. As the polymerization solvent, aromatic solvents such as toluene, ethylbenzene, propylbenzene, and butylbenzene are preferred, and alcohols (for example, 2-ethyl-1-hexanol, n-octanol, etc. are preferred) or ketones as necessary. A solvent system in which the solubility of the styrene resin (A) is adjusted by combining a polar solvent such as (cyclohexanone, etc.) may also be used.
In this embodiment, the polymerization solvent is preferably used in an amount of 1 to 40% by mass, more preferably 3 to 35% by mass, when the total amount of reaction raw materials for producing the styrenic resin (A) is 100% by mass. The amount is preferably in the range of 5 to 30% by weight, even more preferably 7 to 20% by weight. If the polymerization solvent exceeds 40% by mass relative to 100% by mass of the reaction raw materials, the polymerization rate decreases, productivity decreases, and the resulting resin molecular weight also decreases, so the mechanical strength of the resin tends to decrease. Furthermore, if the polymerization solvent is less than 1% by mass, it may become difficult to control heat removal during polymerization. It is preferable to add it in a proportion of 1 to 40% by mass based on 100% by mass of the reaction raw materials, since quality can be easily uniformized and polymerization temperature can be controlled.

In addition, when adding monohydric alcohol (G) having 10 or more carbon atoms, which is an optional component of the styrenic resin composition of the present embodiment, from the polymerization system, (G) is added to 100% by mass of the total polymerization solvent. Preferably, the components are added in a proportion of 0.5 to 10% by mass.

It is preferable that the reaction raw material contains 4-methoxyphenol or hydroquinone as the first component (B) described below. The concentration of component (B) in the reaction raw material is preferably 0.1 μg/g or more and 200 μg/g or less, and more preferably 0.2 μg/g or more, 0.5 μg/g or more, and 0.8 μg/g as the lower limit. g or more, 1.1 μg/g or more, 1.3 μg/g or more, 1.6 μg/g or more, 1.9 μg/g or more, 2.2 μg/g or more, 2.5 μg/g or more, 2.8 μg/g Above, the order is 3.1 μg/g or more, 3.5 μg/g or more, and the upper limit is more preferably 150 μg/g or less, 110 μg/g or less, 90 μg/g or less, 80 μg/g or less, and 70 μg/g or less. , 60 μg/g or less, 50 μg/g or less, 40 μg/g or less, 30 μg/g or less, 20 μg/g or less, 18 μg/g or less, 16 μg/g or less, 14 μg/g or less, 12 μg/g or less, 10 μg/g or less , 9 μg/g or less, 8 μg/g or less, 7 μg/g or less, 6 μg/g or less, and 5 μg/g or less. By setting the amount of 0.1 μg/g or more to 200 μg/g, polymerization of the polymerization raw materials (each monomer component) in the reaction raw materials can be appropriately started at any timing, and in particular, if the amount is 0.8 μg/g or more and 12 μg/g A styrenic resin (A) with excellent color tone can be obtained by using the following conditions.

The apparatus used in the polymerization step for obtaining the styrenic resin (A) in this embodiment is not particularly limited, and may be appropriately selected according to a general method for polymerizing styrenic resins. For example, in the case of bulk polymerization, a polymerization apparatus in which one or more complete mixing type reactors are connected can be used. There are also no particular restrictions on the devolatilization step, and when performing bulk polymerization or solution polymerization using a solvent, the polymer content before entering the devolatilization step is the same as the remaining polymerization raw material composition and the polymerization raw material in the polymerization step. It is preferable to advance the polymerization until the total amount (100% by mass) of the polymer produced by polymerizing is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably It is 60% by mass or more. When the content of the polymer is 50% by mass or less, the load applied in the devolatilization step becomes high, and there is a possibility that the amount of low molecular weight components contained in the styrenic resin (A) increases.

In the devolatilization step, a known method is used to remove volatile components such as unreacted polymerization raw materials. For example, ordinary devolatilization equipment such as a flash tank, twin-screw devolatilizer, thin film evaporator, or extruder can be used, but no matter which devolatilization equipment is used, two or more devolatilization equipment are connected in series. A devolatilization process consisting of two or more stages of devolatilization treatment is preferred. The temperature of the devolatilization treatment is usually about 150 to 290°C, more preferably 160 to 270°C, still more preferably 170 to 260°C.
The pressure for the devolatilization treatment is usually about 0.13 to 100 kPa, preferably 0.13 to 80 kPa, and more preferably 0.13 to 70 kPa. Desirable devolatilization methods include, for example, a method in which volatile components are removed under reduced pressure under heating, and a method in which volatile components are removed through an extruder or the like designed for the purpose of removing volatile components.

"First component (B)"
The styrenic resin composition of this embodiment contains the first component (B). The first component (B) contains one or more selected from the group consisting of 4-methoxyphenol and hydroquinone. The content of the first component (B) is less than 1 μg per 1 g of styrene resin (A). By setting it as such a range, strength retention after light exposure is excellent. The content of component (B) per 1 g of styrenic resin (A) is, for example, 0 (including the lower limit of detection), more than 0, 0.01, 0.03, 0.05, 0.07, 0.09, 0.10, 0.20, 0.22, 0.30, 0.32, 0.40, 0.42, 0.50, 0.60, 0.70, 0.80, 0. 88, 0.90, 0.92, 0.94, 0.96, 0.97, 0.98, 0.99 μg, even if it is within the range between any two of the numerical values exemplified here. good.

Component (B) of this embodiment may be added after being dissolved in a monomer or solvent during polymerization of the styrenic resin (A), or may be added later using an extruder or mixer. Further, it may be removed by methods such as distillation, devolatilization, adsorption and removal, or adjusted to a desired content.
The content of component (B) was measured by gas chromatography (GC) using the method described below.

"Core-shell type rubbery polymer particles (C)"
In a preferred embodiment of the present embodiment, the styrenic resin composition of the present embodiment has (meth)acrylic acid added to rubber-like polymer particles containing a conjugated diene monomer unit (c1) (for example, a butadiene monomer unit). It is preferable to further contain core-shell type rubbery polymer particles (C) (also simply referred to as core-shell particles (C)) formed by grafting a copolymer mainly composed of ester monomer units (c2).
The core-shell type rubbery polymer particles (C) of the present embodiment have a rubbery particle containing a conjugated diene monomer unit (c1) as a core, and a shell portion that at least partially covers the core ( It has a structure coated with a copolymer mainly composed of meth)acrylic acid ester monomer units (c2).

The content of the core-shell type rubbery polymer particles (C) is preferably 0.1 to 50% by mass, more preferably 2.0 to 45% by mass, based on the total amount of the styrenic resin composition. , more preferably from 3.6 to 35% by weight, even more preferably from 5.4 to 25% by weight, and most preferably from 6.0 to 15% by weight. By setting the content to 0.1% by mass or more, an effect of improving mechanical strength can be obtained, and by setting the content to 50% by mass or less, a decrease in rigidity can be prevented.
The conjugated diene monomer (c1) constituting the core-shell type rubbery polymer particles (C) is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl- Examples include 1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene.
The (meth)acrylic acid ester monomer unit (c2) constituting the core-shell type rubbery polymer particles (C) includes a methacrylic acid ester monomer unit and an acrylic acid ester monomer unit. In addition, (meth)acrylic acid ester monomer units include methyl acrylate, ethyl acrylate, (n-butyl) acrylate, (2-ethylhexyl) acrylate, (n-octyl) acrylate, and benzyl acrylate. , methyl methacrylate, butyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, (2-ethylhexyl) methacrylate, (n-octyl) methacrylate, benzyl methacrylate, etc. Methyl acrylate, n-butyl acrylate, and methyl methacrylate are preferred because they are easily available industrially and are inexpensive.

The content of the conjugated diene monomer unit (c1) in the core-shell type rubbery polymer particles (C) is preferably 30 to 90% by mass, more preferably 40 to 85% by mass, even more preferably 50 to 80% by mass. % by weight, more preferably 55 to 75% by weight. It is preferable that the higher the content of the conjugated diene monomer unit (c1), the greater the improvement in mechanical strength with a smaller addition amount. On the other hand, if the content of the conjugated diene monomer unit (c1) is too high, the content of the graft copolymer mainly composed of the (meth)acrylic acid ester monomer unit (c2) will decrease, and the styrene The decrease in compatibility with the system resin (A) causes a decrease in the effect of improving mechanical strength.

The content of (meth)acrylic acid ester monomer units (c2) in the core-shell type rubbery polymer particles (C) is preferably 10 to 40% by mass, more preferably 12 to 35% by mass, even more preferably It is 15 to 25% by mass. By setting the content of the (meth)acrylic acid ester monomer unit (c2) in the range of 10 to 40% by mass, compatibility with the styrene resin (A) can be ensured, and mechanical strength can be improved. Effects can be obtained efficiently.

The shell portion of the core-shell type rubbery polymer particles (C) is composed of a copolymer whose main component is a (meth)acrylic acid ester monomer unit (c2). It means that the content of the (meth)acrylic acid ester monomer unit (c2) is 50% by mass or more when the total amount of the copolymer constituting the structure is 100% by mass.

The composition of the shell part in the core-shell type rubbery polymer particles (C) is, when the total amount of the copolymer constituting the shell structure is 100% by mass, (meth)acrylic acid ester monomer units (c2) The content is preferably 55% by mass or more, 60% by mass or more, 63% by mass or more, 66% by mass or more, 70% by mass or more, 73% by mass or more, 76% by mass or more, 80% by mass or more, 83% by mass or more. , 86% by mass or more, 90% by mass or more, 93% by mass or more, 96% by mass or more, 99% by mass or more, and 100% by mass.

The composition of the shell portion of the core-shell type rubbery polymer particles (C) includes other monomer units (c3) other than the (meth)acrylic acid ester monomer unit (c2) within a range that does not impair the effects of the present invention. Examples thereof include styrene monomer units, unsaturated nitrile monomer units, and unsaturated dicarboxylic anhydride monomer units.

The content of other monomer units (c3) is preferably 45% by mass or less, 40% by mass or less, 37% by mass or less, when the total amount of the copolymer constituting the shell structure is 100% by mass. 34% by mass or less, 30% by mass or less, 27% by mass or less, 24% by mass or less, 20% by mass or less, 17% by mass or less, 14% by mass or less, 10% by mass or less, 7% by mass or less, 4% by mass or less, The order of 0% by mass is more preferable.

<Particle diameter of core-shell type rubbery polymer particles (C)>
The average particle diameter of the core-shell type rubbery polymer particles (C) of this embodiment is preferably 0.05 to 0.35 μm, more preferably 0.080 to 0.30 μm, and even more preferably 0.10 to 0.0 μm. .25 μm, more preferably 0.15 to 0.23 μm. In particular, when the particle size is in the range of 0.15 to 0.23 μm, the strength imparting effect of the styrene resin composition is excellent.
In the present disclosure, the average particle diameter is measured from a cross-sectional observation image using a transmission electron microscope, as shown in the Examples section below.

<Method for producing core-shell type rubbery polymer particles (C)>
The method for producing the core-shell type rubbery polymer particles (C) of this embodiment includes producing conjugated diene rubber latex (for example, butadiene rubber latex) particles, and then adding (meth)acrylic acid ester monomer (c2 ) and other monomers (c3) are preferably graft copolymerized.

"Impact-resistant styrenic resin (D)"
As a preferred aspect of this embodiment, the styrenic resin composition preferably contains an impact-resistant styrenic resin (D) (also simply referred to as resin (D)). When the styrene resin composition contains an appropriate amount of the rubber-modified styrenic resin (D), a styrenic resin composition capable of producing a molded article with excellent strength can be obtained.

The impact-resistant styrenic resin (D) of this embodiment is produced by dispersing a rubbery polymer in a monomer solution consisting of a styrene monomer (d1) and, if necessary, other monomers (d3). , in the presence of the rubbery polymer, the styrenic monomer (d1) and other monomers (d3) are polymerized as necessary while stirring. A polymer matrix (D-1) consisting of a polymer having monomer units derived from the monomer (d3), a rubbery polymer, a styrene monomer (d1), and other monomers as necessary. It may be a so-called high impact polystyrene resin (HIPS resin) consisting of a mixture of rubber-like polymer particles (D-2) having a salami structure formed by graft copolymerization of (d3).

In other words, the impact-resistant styrenic resin (D) of the present embodiment consists of a polymer matrix (D-1) and the same monomer units as those contained in the polymer matrix (D-1). The polymer contains rubbery polymer particles (D-2) that are graft copolymerized with the rubbery polymer. The polymer matrix (D-1) contains a polymer obtained by polymerizing a styrene monomer (d1) and other monomers (d3) blended as necessary. Further, the rubbery polymer particles (D-2) are particles of a rubbery polymer (D-2) mainly composed of a conjugated diene monomer unit (d2), and a styrene monomer unit. The surface of the particles is grafted with a polymer containing (d1) and other monomer units (d3), and the interior of the particles contains styrenic monomer units (d1) and other monomer units ( These particles have a so-called salami structure morphology in which subdomains made of a polymer containing d3) are formed.

The content of the impact-resistant styrenic resin (D) in the styrenic composition of the present embodiment is preferably 0.1 to 50% by mass, more preferably 1% by mass, based on the total amount of the styrenic resin composition. The range is from 40% by weight, more preferably from 2 to 31% by weight, even more preferably from 7 to 20% by weight. By setting the content of the impact-resistant styrenic resin (D) in the range of 0.1 to 50% by mass, a styrenic resin composition with even better strength can be obtained.

-Rubber-like polymer particles (D-2)-
In this embodiment, the rubbery polymer (D-2) constituting the rubbery polymer particles (D-2) in the impact-resistant styrene resin (D) is a conjugated diene monomer (d2). It is preferably formed from a polymer having a conjugated diene monomer unit (d2). Specific examples of the rubbery polymer (D-2) include polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc.; , polybutadiene and styrene-butadiene copolymers are preferred. As the polybutadiene, high-cis polybutadiene with a high cis content, low-cis polybutadiene with a low cis content, or both of these can be used. The structure of the styrene-butadiene copolymer may be a random structure, a block structure, or a combination thereof. These rubbery polymers may be used alone or in combination of two or more. Saturated rubber obtained by hydrogenating butadiene rubber can also be used.

In the present specification, the "conjugated diene monomer" is a general term for the above-mentioned conjugated diene monomer (c1) and conjugated diene monomer (d1).

The conjugated diene monomer is a diolefin having a pair of conjugated double bonds among the monomer units constituting the rubbery polymer particles, such as 1,3-butadiene, 2-methyl-1 , 3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like.
The rubbery polymer particles (D-2) in this embodiment are a polymer containing a styrene monomer unit (d1) in the dispersed particles of the rubbery polymer (D-2) or a styrene monomer unit (d1). It contains a polymer containing a mer unit (d1) and other monomers (d3). The form of the inclusion is that a domain phase of a polymer having styrene monomer units (d1) is combined with a plurality of rubbery polymers (D
-2) is preferably a so-called salami structure type dispersion particle.
-Other monomers (d3)-
Other monomers (units) (e3) that are optional components of the impact-resistant styrenic resin (D) of this embodiment include methyl acrylate, ethyl acrylate, propyl acrylate, and acrylic acid (n-butyl). , isopropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, (n-butyl) methacrylate, isopropyl methacrylate, other (meth)acrylic acid ester monomers, acrylonitrile, methacrylonitrile, other unsaturated nitrile monomers Examples include mer units, maleic anhydride, N-phenylmaleimide, N-cyclohexylmaleimide, etc., but acrylic acid (n-butyl), methyl methacrylate, and acrylonitrile are preferred from the viewpoint of industrial availability.
In this embodiment, the content of other monomers (units) (d3) in the impact-resistant styrenic resin (D) is 70% by mass or less with respect to the total amount of the impact-resistant styrenic resin (D). The content is preferably 60% by mass or less, more preferably 50% by mass or less, and most preferably 45% by mass or less.

<Content of conjugated diene monomer unit (d2)>
In this embodiment, the content of the conjugated diene monomer unit (d2) in the impact-resistant styrenic resin (D) is preferably 0.000000000000000000000 with respect to the total amount of the impact-resistant styrenic resin (D). The content is in the range of 5 to 30% by weight, more preferably 1.0 to 25% by weight, even more preferably 2.5 to 20% by weight, even more preferably 5 to 15% by weight. The content of the conjugated diene monomer unit (d2) in the impact-resistant styrenic resin (D) and the styrenic resin composition can be determined by the procedure described in the Examples section below, or by an equivalent method. can be measured.

<Average particle diameter of rubbery polymer particles (D-2)>
The rubbery polymer (D-2), which is the rubber component in the impact-resistant styrenic resin (D) in this embodiment, is present in the styrenic resin composition as particles of the rubbery polymer (D-2). are doing. In this case, the average particle diameter of the rubbery polymer particles (D-2) is preferably 0.3 to 5.0 μm, more preferably 0.5 to 4.0 μm, even more preferably 0.7 to 3.0 μm, Even more preferably, it is in the range of 1.0 to 2.5 μm. Impact-resistant styrenic resin (D) is produced by polymerizing styrenic monomer (d1) and other monomers (d3) in a reactor equipped with a stirrer in the presence of rubbery polymer particles (D-2). However, the average particle diameter of the rubbery polymer particles (D-2) can be adjusted by adjusting the rotation speed of the stirrer, the molecular weight of the rubbery polymer (D-2) used, etc. In the present disclosure, the average particle diameter of the rubbery polymer particles (D-2) is a value measured from a cross-sectional observation image using a transmission electron microscope, as shown in the Examples section below. The rubbery polymer particles (D-2) are elongated during processing such as foaming and stretching in the later-described bifoamed sheet, and the particle size increases by about 150 to 400%.

In this embodiment, the melt flow rate at 200°C of the impact-resistant styrenic resin (D) is preferably 0.3 to 10.0 g/10 minutes, more preferably 0.5 to 8.0 g/10 minutes. , more preferably 0.7 to 7.0 g/10 minutes. When the melt flow rate is in the range of 0.3 to 10.0 g/10 minutes, the mixture has good miscibility with the styrene resin (A) and also has good mechanical strength. In the present disclosure, the melt flow rate is a value measured at 200° C. and a load of 49N in accordance with ISO 1133.

<Production method of impact-resistant styrenic resin (D)>
The method for producing the impact-resistant styrenic resin (D) is not particularly limited, but in the presence of a rubbery polymer, a styrenic monomer (d1) and other monomers (d3) as necessary are added. , and bulk polymerization (or solution polymerization) in which a solvent is polymerized, bulk-suspension polymerization in which the reaction transitions to suspension polymerization, or styrenic monomer (d1) in the presence of latex particles, which are rubber-like polymers. It can be produced by emulsion graft polymerization. In bulk polymerization, a mixture of a rubbery polymer, a styrene monomer (d1), and, if necessary, other monomers (d3), an organic solvent, an organic peroxide, and/or a chain transfer agent is added. The solution can be produced by continuously supplying the solution to a polymerization apparatus configured by connecting a complete mixing reactor or a tank reactor and a plurality of tank reactors in series.

"(Meth)acrylic resin (E)"
The styrenic resin composition in this embodiment preferably contains (meth)acrylic resin (E) (also simply referred to as resin (E)) with respect to the total amount of the styrenic resin composition. The (meth)acrylic resin (E) has an unsaturated carboxylic acid monomer unit (b1). Containing a predetermined amount of (meth)acrylic resin (E) contributes to improving the transparency and mechanical strength of the styrene resin composition as a whole.
Note that (meth)acrylic resin (E) in this specification is a general term for synthetic resins containing 50% or more of unsaturated carboxylic acid monomer units (b1).
In addition, in the present invention, the number average molecular weight (Mn), weight average molecular weight (Mw), and Z average molecular weight (Mz) of the (meth)acrylic resin (E) are as described in the Examples section below. This is a value measured in terms of standard polystyrene based on data detected with a differential refractometer using permeation chromatography (GPC).

(meth)acrylic resin (E
) content is preferably 0.1 to 50% by mass, more preferably 10 to 40% by mass, even more preferably 11 to 38% by mass, even more preferably 12 to 34% by mass, most preferably 13 to 30% by mass. Mass%. By setting the content of the (meth)acrylic resin (E) to 10% by mass or more and 40% by mass or less, the oil resistance and strength due to the acrylic resin are suppressed while suppressing a decrease in the heat resistance improved by the styrene resin (A). It is possible to obtain an improvement effect.
The unsaturated carboxylic acid monomer unit (e1) constituting the (meth)acrylic resin (E) of this embodiment is a (meth)acrylic acid monomer unit (e1-1) and a (meth)acrylic acid monomer unit (e1-1). It is preferable that it is at least one type of repeating unit selected from the group consisting of ester monomer units (e1-2), and at least one type of repeating unit selected from the group consisting of (meth)acrylic acid ester monomer units (e1-2). More preferably, two or more types of repeating units are used.

-(meth)acrylic acid monomer (e1-1)-
In this embodiment, the (meth)acrylic acid monomer (e1-1) includes acrylic acid and methacrylic acid.

-(meth)acrylic acid ester monomer (e1-2)-
The (meth)acrylic acid ester monomer unit (e1) constituting the (meth)acrylic resin (E) of the present embodiment includes a methacrylic acid ester monomer unit and an acrylic acid ester monomer unit. In addition, examples of the (meth)acrylic acid ester monomer (e1) include methyl acrylate, ethyl acrylate, (n-butyl) acrylate, (2-ethylhexyl) acrylate, (n-octyl) acrylate, and acrylic acid (n-butyl). Benzyl methacrylate, methyl methacrylate, butyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, (2-ethylhexyl) methacrylate, (n-octyl) methacrylate, benzyl methacrylate , stearyl methacrylate, etc. Methyl acrylate, acrylic acid (n-butyl), methyl methacrylate, methacrylic acid (2-ethylhexyl), methacrylic acid (n-octyl) ) is preferred. The (meth)acrylic ester monomer (b1-2) can be used alone or in combination, and it is preferable to combine two types of (meth)acrylic ester monomers.
From the viewpoint of achieving both heat resistance and thermal decomposability, the combination of monomer units constituting the (meth)acrylic resin (E) of this embodiment is selected from among the monomer units listed above. A copolymer of an acid ester species and an acrylic ester species is preferred, and a methyl methacrylate-methyl acrylate copolymer is more preferred.

<Preferred form of (meth)acrylic resin (E)>
The preferred (meth)acrylic resin (E) of this embodiment is preferably a binary or ternary copolymer, in which methacrylic ester species (methacrylic ester monomer units) and acrylic ester species ( methacrylic ester-acrylic ester copolymer copolymerized with acrylic ester monomer unit), and the acrylic ester monomer unit is copolymerized with respect to the total amount of the methacrylic ester-acrylic ester copolymer. A copolymer containing 0.1 to 25% by mass of acrylic ester monomer units is preferred, and a copolymer containing 0.5 to 17 mass % of acrylic ester monomer units is more preferred, and 1. A copolymer containing 0 to 7.0% by mass of an acrylic ester monomer unit is more preferable, and a copolymer containing 1.2 to 4.5 mass % of an acrylic ester monomer unit is even more preferable. Most preferred is a copolymer containing 1.5 to 3.0% by mass of

The preferred (meth)acrylic resin (E) of the present embodiment is a methyl methacrylate-methyl acrylate copolymer, and the methyl acrylate monomer unit is 0.5 to 0.5 to A copolymer containing 17% by mass is more preferred, and a copolymer containing 1.0 to 5.0% by mass of methyl acrylate monomer units is even more preferred. Thereby, the decrease in the heat resistance of the resin composition improved by the styrene resin (A) can be more effectively suppressed.

In the (meth)acrylic resin (E) of this embodiment, the content of the (meth)acrylic acid ester monomer unit (e1-2) in the (meth)acrylic resin (E) is (meth) It is preferably 54% by mass or more, more preferably 64% by mass or more, even more preferably 71% by mass or more, even more preferably 86% by mass or more, and most preferably 91% by mass or more based on the total amount of the acrylic resin (E). % by mass or more. By setting the content of the methacrylic acid ester monomer (e1-2) in the range of 55.0 to 100% by mass, it becomes possible to withstand kneading and extrusion with other resins and molding processing at 300° C. or lower. Therefore, it is possible to suppress a significant decrease in heat resistance when the styrene resin (A) and (meth)acrylic resin (E) are mixed. As for the type of (meth)acrylic acid ester monomer (e1-2), methyl acrylate or methyl methacrylate is preferred because of its heat resistance, industrial availability, and low cost.

<Other monomers (e2)>
The (meth)acrylic resin (E) of this embodiment includes other monomer units other than the above-mentioned (meth)acrylic acid monomer (e1-1) and (meth)acrylic acid ester monomer unit (e1-2). It may further have a mer unit (e2). That is, the other monomer unit (e2) is an unsaturated carboxylic acid monomer unit (e1) ((meth)acrylic acid monomer (b1-1) and/or (meth)acrylic acid ester monomer (including monomers (e1-2)), without any particular limitation, as long as it is possible to copolymerize with monomers other than the monomers shown above, to the extent that the effects of the invention are not impaired. good. For example, monomers (e2) other than the monomers shown above include styrene, maleic anhydride, maleic acid, fumaric acid, itaconic acid, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, Examples include maleimide, nuclear-substituted maleimide, and the like.
In this embodiment, the content of the other monomer units (e2) is preferably 0 to 30% by mass, and preferably 0 to 20% by mass, based on the total amount of the (meth)acrylic resin (E). It is more preferably 0 to 15% by mass, even more preferably 0 to 7% by mass.

The upper limit of the weight average molecular weight (Mw) of the (meth)acrylic resin (E) is 8 million or less, 6 million or less, 5 million or less, 3 million or less, 2 million or less in terms of standard polystyrene using the GPC method described below. The following preferred order is 1 million or less, 900,000 or less, 500,000 or less, 400,000 or less, 300,000 or less, 200,000 or less, 150,000 or less, and the lower limit values are 40,000 or more, 50,000 or more, 60,000 or more, The preferred order is 70,000 or more and 80,000 or more. As for the range of weight average molecular weight (Mw) of the (meth)acrylic resin (E), the above upper limit and lower limit can be arbitrarily combined, but in particular, by setting it to 70,000 or more, a resin composition with excellent strength can be obtained. By setting the viscosity to 1 million or less, the difference in viscosity with the styrene resin (A) can be suppressed, and as a result, the (meth)acrylic resin (E) can be added to the styrene resin composition. can be dispersed well, the generation of unmelted substances derived from the (meth)acrylic resin (E) can be suppressed, and a molded article with a good appearance can be obtained using the composition, and Since the viscosity of the resin composition can be lowered, a resin composition with good injection molding cycles can be obtained.

The value of the weight average molecular weight (Mn) of the (meth)acrylic resin (E) is preferably 20,000 to 1,500,000, more preferably 25,000 to 300,000, in terms of standard polystyrene by the GPC method described below. Even more preferably, it is in the range of 30,000 to 120,000.

The value of the weight average molecular weight (Mz) of the (meth)acrylic resin (E) is preferably 80,000 to 10,000,000, more preferably 90,000 to 800,000, and even more It is preferably in the range of 100,000 to 300,000.

The value of the dispersity (Mw/Mn) of the (meth)acrylic resin (E) is preferably 1.1 to 6.0, more preferably 1.3 to 4 in terms of standard polystyrene by the GPC method described below. .0, more preferably in the range of 1.5 to 3.7. In particular, by setting it within the range of 1.5 to 3.7, a styrenic resin composition with an excellent balance between moldability and strength can be obtained.

<Method for producing (meth)acrylic resin (E)>
The method for producing the (meth)acrylic resin (E) of this embodiment is not particularly limited, but includes bulk polymerization in which a (meth)acrylic acid ester monomer and other monomers are polymerized as necessary; It can be produced by processes such as solution polymerization in which a solvent is added, suspension polymerization in which an organic layer is dispersed in water using a suspending agent, and emulsion polymerization.

"t-Butylcatechol (F)"
The styrenic resin composition in this embodiment preferably contains t-butylcatechol (F) (hereinafter referred to as component (F)). The content of t-butylcatechol (F) is less than 20 μg per 1 g of styrenic resin (A). By setting it as such a range, a styrenic resin composition with excellent transparency and hue can be obtained. Specifically, the content of t-butylcatechol (F) per 1 g of styrene resin (A) is, for example, 0, more than 0, 0.1, 0.3, 0.5, 0.7, 0. 9, 1.0, 1.5, 2.3, 2.6, 3.0, 3.3, 3.6, 4.0, 4.3, 4.6, 5.0, 5.3, 5.6, 6.0, 6.3, 6.6, 7.0, 7.3, 7.6, 8.0, 8.3, 8.6, 9.0, 9.3, 9. 6, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 μg, and may be within the range between any two of the numerical values exemplified here.

t-Butylcatechol (F) may be added after being dissolved in a monomer or solvent during the polymerization of the styrene resin (A), or may be added later using an extruder or mixer. Further, it may be removed by methods such as distillation, devolatilization, adsorption and removal, or adjusted to a desired content.

The content of t-butylcatechol (F) was measured by gas chromatography (GC) using the method described below.

"Monohydric alcohol (G) having 10 or more carbon atoms"
In this embodiment, the monohydric alcohol (G) having 10 or more carbon atoms (hereinafter also simply referred to as alcohol (G)) is an optional component and suppresses gelation of the styrene resin (A) during molding, resulting in a good This contributes to improving the appearance of a styrene-based resin composition and a molded article made of a styrene-based resin composition. The content of the monohydric alcohol (G) having 10 or more carbon atoms is preferably 0.001 to 2.0% by mass, more preferably 0.001% to 2.0% by mass, based on the total amount (100% by mass) of the styrene resin composition. 0.02 to 0.8% by weight, more preferably 0.05 to 0.6% by weight, even more preferably 0.07 to 0.5% by weight. By setting the content of the monohydric alcohol (E) having 10 or more carbon atoms to 0.02% by mass or more, gelation of the styrenic resin (A) during molding can be suppressed, and 1.0 By controlling the amount to be less than % by mass, it is possible to suppress a decrease in heat resistance and the generation of odor. By setting the content of the monohydric alcohol (G) having 10 or more carbon atoms to 0.07 to 0.5% by mass, a sufficient gel-suppressing effect can be obtained without particularly reducing heat resistance.

A monohydric alcohol (G) having 10 or more carbon atoms is an alcohol having 10 or more carbon atoms containing one hydroxyl group, and does not contain a heteroatom such as oxygen or nitrogen in the carbon chain constituting the alcohol (G). The carbon chain may also contain bonds other than single bonds, such as double bonds, triple bonds, ester bonds, and amide bonds. The number of carbon atoms is preferably 16 or more, more preferably 17 or more, and even more preferably 18 or more and 50 or less. The monohydric alcohol (G) having 10 or more carbon atoms may be contained in a styrenic resin composition or a molded article made of a styrene resin composition. Therefore, by adding (or adding) a monohydric alcohol (G) having 10 or more carbon atoms to the polymerization solution used when polymerizing the styrenic resin (A), the final product, the resin composition. The monohydric alcohol (G) may be left in the monohydric alcohol (G), or may be contained by mixing with an extruder, mixer, or the like.

In this embodiment, the boiling point of the monohydric alcohol (G) having 10 or more carbon atoms is preferably 260°C or higher, more preferably 270°C or higher, even more preferably 290°C or higher. If the boiling point of the alcohol is less than 260°C, the volatility will be high and there is a tendency for an off-odor to occur during molding.

The monohydric alcohol (G) having 10 or more carbon atoms is not particularly limited, but examples include 1-hexadecanol, isohexadecanol, 1-octadecanol, 5,7,7-trimethyl-2- (1,3,3-trimethylbutyl)-1-octanol, isooctadecanol, 1-isoisoeicosanol, 8-methyl-2-(4-methylhexyl)-1-decanol, 2-heptyl-1- Examples include undecanol, 2-heptyl-4-methyl-1-decanol, 2-(1,5-dimethylhexyl)-(5,9-dimethyl)-1-decanol, and polyoxyethylene alkyl ethers.

（上記一般式（２）中、Ｒは炭素原子数１２～２０のアルキル基であり、Ｘはエチレンオキサイドの平均付加数を表し、１～１５の整数である。） The polyoxyethylene alkyl ethers are preferably compounds represented by the following general formula (2).

(In the above general formula (2), R is an alkyl group having 12 to 20 carbon atoms, and X represents the average addition number of ethylene oxide and is an integer of 1 to 15.)

Specific product names of preferred alcohols (G) include "Fine Oxocol 180" manufactured by Nissan Chemical Co., Ltd., "Calcol 8098" manufactured by Kao Corporation, and "Emulgen 109P" manufactured by Kao Corporation.

"Other ingredients"
In addition to the above-mentioned components, the styrenic resin composition of this embodiment contains various additives commonly used in styrene resins (hereinafter referred to as other components) in order to achieve known effects. It can also be used as a resin composition. Examples of the other components include stabilizers, higher fatty acid surfactants, antioxidants, plasticizers, antiblocking agents, antistatic agents, antifogging agents, and mineral oil. In addition, thermoplastics such as styrene-maleic anhydride copolymer, methyl methacrylate-butyl acrylate block copolymer, methyl methacrylate-(2-ethylhexyl acrylate) block copolymer, and styrene-butadiene block copolymer Elastomers may also be added to the extent that the physical properties are not impaired. There are no particular regulations regarding the method of blending, but for example, additives may be added during polymerization and then polymerized, or additives may be mixed in advance in a blender before melt-kneading after polymerization, and then in an extruder or Banbury mixer, etc. Examples include a method of melting and kneading.

In particular, from the viewpoint of stability during processing, antioxidants such as octadecyl-3-(3,5-tert-butyl-4-hydroxyphenyl)propionate, 4,6-bis(octylthiomethyl)-o-cresol ( Product names include, for example, hindered phenol antioxidants such as Irganox 1076 (manufactured by BASF Japan), and tris(2,4-di-tert-butylphenyl) phosphite (product names include Irgafos 168, manufactured by BASF Japan). Examples include phosphorus-based processing heat stabilizers such as . These stabilizers may be used alone or in combination of two or more as appropriate. There is no particular restriction on the timing of addition, and it may be added during either the polymerization step or the devolatilization step. The stabilizer can also be mixed into the product using a mechanical device such as an extruder or mixer.

[Physical properties of styrenic resin composition]
The physical properties of the styrenic resin composition in this embodiment will be described below.
<Vicat softening temperature>
In this embodiment, the Vicat softening temperature of the styrenic resin composition is preferably 105°C or higher, more preferably 110°C or higher, even more preferably 115°C or higher. By setting the Vicat softening temperature to 105°C or higher, a molded product that does not undergo thermal dimensional deformation even inside a car during the daytime can be obtained, and by setting the Vicat softening temperature to 110°C or higher, a molded product that does not easily undergo thermal dimensional deformation even inside a car during the daytime in summer can be obtained. can get. As mentioned above, the Vicat softening temperature can be measured in accordance with ISO306 under the conditions of a 5 kg load and a temperature increase rate of 50° C./h.

<Melt mass flow rate>
In this embodiment, the melt flow rate of the styrenic resin composition at 200°C and a load of 5 kg is preferably in the range of 0.1 to 2.0 g/10 minutes, more preferably 0.2 to 1.5 g. /10 minutes, more preferably 0.4 to 1.0 g/10 minutes. By setting the melt flow rate to 0.3 g/10 minutes or more, good moldability can be obtained, and by setting the melt flow rate to 2.0 g/10 minutes or less, a resin with excellent strength can be obtained.

<Content of conjugated diene monomer unit>
In this embodiment, the total content of conjugated diene monomer units derived from HIPS resin, MBS resin, ABS resin, styrenic elastomer, core-shell type butadiene rubber particles, etc. added as necessary is the styrene resin composition. The amount is preferably 0 to 10% by weight, more preferably 0.05 to 7% by weight, even more preferably 0.10 to 5% by weight, even more preferably 0.20 to 3% by weight, based on the entire product. By setting the content of the conjugated diene monomer unit within the above range, a composition with an excellent balance between transparency and strength can be obtained.

The styrenic resin composition of this embodiment has a resin (A), a first component (B), core-shell type rubbery polymer particles (C), and optional additive components, and the resin (A), It is preferable that the total content of the first component (B), core-shell type rubbery polymer particles (C), and optional additive components accounts for 85 to 100% by mass, and more preferably Preferably, it may be 90 to 95% by mass.
The styrenic resin composition of this embodiment has a resin (A), a first component (B), and an impact-resistant styrenic resin (D), and the resin (A), the first component (B), and The total content of the impact-resistant styrenic resin (D) may preferably be 70 to 100% by mass, more preferably 80 to 90% by mass, based on the entire styrenic resin composition.
The styrenic resin composition of this embodiment has a resin (A), a first component (B), a (meth)acrylic resin (E), and an optional additive component, and the resin (A), the first component The total content of component (B), (meth)acrylic resin (E), and optional additive components is preferably 85 to 100% by mass, more preferably 90 to 100% by mass, based on the entire styrenic resin composition. It can be 95% by mass.
The styrenic resin composition of the present embodiment has a resin (A), a first component (B), and t-butylcatechol (F), and has a resin (A), a first component (B), and t-butylcatechol. The total content of butylcatechol (F) may preferably be 60 to 100% by mass, more preferably 75 to 98% by mass, based on the entire styrenic resin composition.
The styrenic resin composition of this embodiment has a resin (A), a first component (B), a monohydric alcohol (G) having 10 or more carbon atoms, and an optional additive component, and the resin (A) , the total content of the first component (B), the monohydric alcohol having 10 or more carbon atoms (G), and any additional components preferably accounts for 75 to 100% by mass of the entire styrenic resin composition. , more preferably 80 to 98% by mass.

[Injection molded products]
Another aspect of the present invention is a molded article manufactured by injection molding, which has excellent heat resistance, transparency, weather resistance, mechanical strength, and surface hardness, and can therefore be suitably used for in-vehicle applications.

Next, the present invention will be explained in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The analysis and evaluation methods for resins and molded articles in Examples and Comparative Examples are as follows.

[Characteristic evaluation of each resin and resin composition]
(1) Measurement of weight average molecular weight The number average molecular weight (Mn), weight average molecular weight (Mw), and Z average molecular weight (Mz) of each resin and resin composition manufactured in Examples and Comparative Examples were measured by gel permeation chromatography ( GPC) under the following conditions.
Measuring equipment: Tosoh HLC-8220
Separation column: Two Tosoh TSK gel Super HZM-H (inner diameter 4.6 mm) connected in series Guard column: Tosoh TSK guard column Super HZ-H
Measurement solvent: Tetrahydrofuran (THF)
Sample concentration: 5 mg of the measurement sample was dissolved in 10 mL of solvent, and filtered through a 0.45 μm filter.
Injection volume: 10μL
Measurement temperature: 40℃
Flow rate: 0.35 mL/min Detector: Differential refractometer To create the calibration curve, 11 types of TSK standard polystyrene manufactured by Tosoh (F-850, F-450, F-128, F-80, F-40, F -20, F-10, F-4, F-2, F-1, A-5000). A calibration curve was created using a linear linear approximation formula.

(2) Measurement of melt mass flow rate (MFR) The melt mass flow rate (g/10 min) of each resin and resin composition manufactured in Examples and Comparative Examples was measured at 200°C and a load of 49N in accordance with ISO1133. Measured at

(3) Measurement of Vicat Softening Temperature The Vicat softening temperature of each resin and resin composition manufactured in Examples and Comparative Examples was measured in accordance with ISO306. The load was 50N, and the temperature increase rate was 50°C/h. When the Vicat softening temperature exceeds 105°C, it was possible to obtain an injection molded product that is resistant to thermal deformation even at high temperatures of 100°C or higher.

(4) Measurement of content of component (B) and t-butylcatechol (F) in styrenic resin composition The content of component (B) in the styrene resin composition was measured by the following method. After the pellets were sufficiently dissolved in 20 ml of methyl ethyl ketone, 5 ml of methanol was added dropwise and stirred for about 20 minutes. The supernatant liquid separated by centrifugation was measured using gas chromatography (GC). A calibration curve prepared in advance for each antioxidant was used to determine the concentration.
GC measurement conditions:
GC device: Shimadzu GC-2010
Column: DB-1 (0.25mm i.d. x 30m)
Liquid phase thickness 0.10mm
Column temperature: 240°C (held for 1 min) →
(10°C/min temperature increase) →
320°C (held for 5 min) Total 14 min
Inlet temperature: 320°C
Injection method: Split method (split ratio 1:5)
Sample amount: 1μl

(5) Measurement of the content of monohydric alcohol (G) having 10 or more carbon atoms in the styrene resin composition The content of monohydric alcohol (G) having 10 or more carbon atoms in the entire styrene resin composition , was measured using gas chromatography under the following conditions.
Sample preparation: Dissolve 1.0 g of resin in 5 mL of methyl ethyl ketone, then add 5 mL of hexane with p-diethylbenzene adjusted to 200 μg/g as a standard substance to reprecipitate the polymer component, collect the supernatant liquid, and add the measurement solution. And so.
Measuring equipment: Agilent 6850 series GC system Detector: FID
Column: DB-WAX
Length: 60m
Film thickness: 0.50μm
Diameter: 0.320mmφ
Injection volume: 1μL
Split ratio: 50:1
Column temperature: Hold at 100°C for 5 minutes → Raise the temperature to 130°C at 10°C/min → Raise the temperature to 180°C at 10°C/min → Hold at 180°C for 10 minutes → Raise the temperature to 220°C at 20°C/min → Hold at 220℃ for 10 minutes Inlet temperature: 230℃
Detector temperature: 300℃
Carrier gas: Helium When detecting the peak of monohydric alcohol (G) having 10 or more carbon atoms, in order to avoid overlapping other peaks and saturation of the peak intensity, pretreatment such as dilution of the sample and use of Detection conditions such as the column to be used and the split ratio may be adjusted as appropriate.

(6) Measurement of the content of (meth)acrylic acid monomer units The (meth)acrylic acid contained in each resin and resin composition stream prepared in Examples and Comparative Examples by neutralization titration using the following method. The content of acid monomer units was measured.
Weigh out 0.50 g of resin, dissolve it in a mixed solution of toluene/ethanol = 8/2 (volume ratio), perform neutralization titration with a 0.1 mol/L ethanol solution of potassium hydroxide, detect the end point, and dissolve it in a mixed solution of toluene/ethanol=8/2 (volume ratio). The mass-based content of (meth)acrylic acid units was calculated from the amount of potassium oxide ethanol solution used. The completion of neutralization titration was measured using an automatic potentiometric titrator, AT-510 manufactured by Kyoto Electronics Industry Co., Ltd.

(7) Measurement of the content of each monomer unit Each monomer unit contained in the resin compositions prepared in Examples and Comparative Examples was measured using a calibration curve prepared in advance by pyrolysis GC/MS under the following conditions. The content of monomer units was measured.
<Measurement conditions>
Pyrolysis unit equipment: Frontier Lab PY-3030D
Heating furnace temperature: 600℃
Boundary temperature: 300℃
GC/MS
Equipment: Shimadzu GCMS-GP2020NX
Column: Ultra Alloy-5
(Length 30m, film thickness 0.25μm, diameter 0.250mmφ)
Column temperature: held at 50°C for 5 minutes, heated at 10°C/min,
Raise the temperature from 100°C at a rate of 7°C/min and hold at 300°C for 10 minutes.
Inlet temperature: 300℃
Detector temperature: 300℃
Split ratio: 1/300
Carrier gas: Helium Detection method: Mass spectrometer (MSD)
Sample amount: 50μg
Detection mode: Scan mode or SIM mode When detecting each monomer peak, in order to avoid overlapping peaks and saturation of peak intensity, pretreatment such as sample dilution rate, column used, and detection conditions should be performed as appropriate. may be adjusted as appropriate.

(8) Measurement of average particle diameter of rubber particles derived from core shell rubber particles (C) and high impact polystyrene (D) Average particle size of rubber particles derived from core shell rubber particles (C) and high impact polystyrene (D) The average particle diameter (μm) of 200 or more rubbery polymer particles observed by cross-sectional observation using a transmission electron microscope is determined by the following formula:
Average particle diameter = Σ(ni×Di ⁴ )/Σ(ni×Di ³ )
{In the above formula, ni is the number of rubbery polymer particles having a particle diameter Di, and Di is the average value of the long axis and short axis of the rubbery polymer particles. }
It was calculated by averaging the particle diameters obtained from images of 5 fields of view.

(9) Evaluation of heat oil resistance Each resin composition produced in Examples and Comparative Examples was molded into a 2.5 mm plate by injection molding, and the styrene resin composition plate was heated with coconut oil (Japanese oil) adjusted to a constant temperature. The maximum temperature at which dimensional changes did not occur visually after immersion in (manufactured by Hikari Pure Chemical Industries, Ltd.) for 15 minutes was defined as the heat-resistant oil temperature, and the heat-oil resistance was evaluated using the following evaluation criteria.
<Evaluation criteria>
◎...Heat-resistant oil temperature is 110℃ or higher 〇...Heat-resistant oil temperature is 100℃ or higher and lower than 110℃ △...Heat-resistant oil temperature is 90℃ or higher and lower than 100℃ ×...Heat-resistant oil temperature is lower than 90℃

(10) Measurement of surface impact strength (kg/cm) After drying each resin composition produced in Examples and Comparative Examples in a dryer with ventilation function at 80°C for 2 hours or more, compression molding at a temperature setting of 250°C It was molded into a sheet with a thickness of 0.7 mm using a machine, and its surface impact strength was measured using a Toyo Seiki film impact tester (No. 195), and the n8 average was taken as the value.

(11) Strength change ratio after light resistance test Each resin composition produced in the Examples and Comparative Examples was injection molded into a type A test piece dumbbell compliant with ISO527-1, and a xenon weather meter Ci4000 manufactured by Atlas was used. The change in strength after the light resistance test was evaluated using the following method. The conditions for the light resistance test were: no rain, black panel temperature 62°C, irradiance at 340 nm of 0.45 W/ ^m2 , and test speed of 5 mm/min for the dumbbell piece after the light resistance test, in accordance with ISO527-1. A tensile test was conducted, and the area of the SS curve was calculated from the obtained SS curve, and the rate of change in strength before and after the light resistance test was determined based on the following formula.
(Intensity change ratio after light resistance test) =
(SS curve area before light resistance test) / (SS curve area after light resistance test) x 100 (%)

[Preparation of each resin and manufacturing example of styrene resin composition]
The preparation of each resin and the specific manufacturing method of the styrene resin composition will be described below.
<Production example of styrenic resin (A)>
-Production of styrenic resin A-1-
70.8 parts by mass of styrene (containing 30 μg/g of t-butylcatechol), 8.9 parts by mass of methacrylic acid (containing 50 μg/g of 4-methoxyphenol), 12.0 parts by mass of ethylbenzene, 2-ethyl-1- Polymerization raw material composition liquid consisting of 2.5 parts by mass of hexanol, 1.5 parts by mass of Fine Oxocol 180 (G-1) manufactured by Nissan Chemical Co., Ltd., and 0.028 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane. was fed at a rate of 7.5 liters/hour into a fully mixed reactor with a capacity of 39 liters and a polymerization temperature controlled at 138°C, until the polymer content at the reactor output was 65%. Polymerized.
Next, it is continuously supplied to the first stage vacuum devolatilizer (jacket temperature 185°C, gauge pressure 63.9 kPa, polymer temperature 168°C) through a first-stage preheater (set temperature 175°C), and unreacted Volatile components such as monomers and polymerization solvents were roughly removed.
Furthermore, it is continuously supplied to the first stage vacuum devolatilizer (jacket temperature 240°C, gauge pressure 1.1 kPa, polymer temperature 235°C) through a two-stage preheater (set temperature 240°C) to remove unreacted monomers. Volatile components such as the polymerization solvent and the like were removed, and the obtained styrenic resin was recovered as resin pellets. The analysis results of the obtained resin A-1 are shown in Table 1.

-Preparation of resins A-2, A-4, A-8-
As shown in Table 1, the feed amount and polymerization conditions of each monomer were adjusted, a reactor configuration was created in which two complete mixing tanks were connected, and resins A-2 and A- 4. A-8 was prepared. Table 1 shows the analysis results of the obtained resins A-2, A-4, and A-8.

-Preparation of resins A-3, A-5, A-6, A-7-
As shown in Table 1, resins A-3, A-5, A-6, and A-7 were prepared in the same manner as resin A-1 by adjusting the feed amount of each monomer and polymerization conditions. Table 1 shows the analysis results of the obtained resins A-3, A-5, A-6, and A-7.

Resins A-1 to A-7 obtained contained residual styrene monomers of about 50 to 800 μg/g, ethylbenzene of about 10 to 200 μg/g, and 2-ethyl-1-hexanol of about 30 to 300 μg/g ( In the case of Production Examples A-4 and A-8, n-octanol is about 30 to 300 μg/g), styrene dimer and trimer are about 1000 to 5000 μg/g, and impurities derived from the residue of the above polymerization raw material composition. It contained. These quantitative determinations were performed in the same manner as in the determination of monohydric alcohol (G) having 10 or more carbon atoms using gas chromatography described above.

<<Core-shell type rubbery polymer particles (C) used in Examples>>
In the examples of this specification, core-shell type rubbery polymer particles (C) having properties shown in Table 2 below were used as the core-shell type rubbery polymer particles (C).

<<Impact-resistant styrenic resin (D) used in Examples>>
In the examples of this specification, impact-resistant styrenic resins (D) having properties shown in Table 3 below were used as impact-resistant styrenic resins (D).

<<(Meth)acrylic resin (E) used in Examples>>
In the examples of this specification, (meth)acrylic resins (E) having properties shown in Table 4 below were used as (meth)acrylic resins (E).

<<Monohydric alcohol (G) having 10 or more carbon atoms used in the examples>>
In the Examples of this specification, the following alcohol species were used as the monohydric alcohol (G) having 10 or more carbon atoms.
As the monohydric alcohol (G-1), Fine Oxokol 180 (compound name: 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol) manufactured by Nissan Chemical Co., Ltd. was used. did.
As the monohydric alcohol (G-2), Emulgen 109P (polyoxyethylene (9) lauryl ether monoalcohol) manufactured by Kao Corporation was used.

<Production example of styrenic resin composition>
-Examples 1 to 7-
As shown in Table 5-1, in Examples 1 to 7, A-1 to A-7 obtained in the above production example were used as styrenic resin compositions and subjected to the above evaluation. The results of each evaluation are shown in Table 5-1.

-Examples 8 to 17-
In the formulations shown in Tables 5-1 and 5-2, styrenic resin (A) and each core-shell type rubber-like polymer particle (C), impact-resistant styrenic resin (D), or (meth) ) The acrylic resin (E) was kneaded and extruded using a twin-screw extruder to obtain a styrene resin composition. The results of each evaluation are shown in Table 5-1 and Table 5-2.

-Comparative example-
A-8 obtained in the above production example was evaluated as a styrenic resin composition. When the content of component (B) exceeded 1 μg/g, the width of the decrease in the SS curve after the light fastness test became large.

The styrenic resin composition of the present disclosure has excellent heat resistance, strength, and strength retention after exposure to light. It has a big role to play in industry.

Claims (14)

The styrenic resin (A) contains a styrene resin (A) and a first component (B), and the styrenic resin (A) contains a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2). A copolymer, the first component (B) contains one or more selected from the group consisting of 4-methoxyphenol and hydroquinone, and the content of the first component (B) is , a styrenic resin composition in which the amount is less than 1 μg per 1 g of the styrenic resin (A). When the total content of the styrene monomer unit (a1) and the (meth)acrylic acid monomer unit (a2) is 100% by mass, the styrene monomer unit (a1) is The styrene according to claim 1, wherein the content is 99.9 to 40% by mass, and the content of the (meth)acrylic acid monomer unit (a2) is 0.1 to 60% by mass. based resin composition. The (meth)acrylic acid monomer unit (a2) is one selected from the group consisting of a methacrylic acid monomer unit (a2-1) and a methacrylic acid ester monomer unit (a2-2), or The styrenic resin composition according to claim 1 or 2, wherein the copolymer contains two types of monomer units, and the copolymer contains a methacrylic acid monomer unit (a2-1). Based on the total amount of the styrene resin composition, core-shell type rubbery polymer particles (C ) The styrenic resin composition according to claim 1 or 2, comprising 0.1% by mass or more and 50% by mass or less. The styrenic resin composition according to claim 1 or 2, comprising 0.1% by mass or more and 50% by mass or less of an impact-resistant styrenic resin (D) based on the total amount of the styrenic resin composition. The styrenic resin composition according to claim 1 or 2, comprising 0.1% by mass or more and 50% by mass or less of (meth)acrylic resin (E) based on the total amount of the styrenic resin composition. The styrenic resin composition according to claim 1 or 2, which contains 20 μg or less of t-butylcatechol (F) per 1 g of the styrene resin (A) based on the total amount of the styrenic resin composition. The styrenic resin according to claim 1 or 2, comprising 0.001% by mass or more and 2.0% by mass or less of a monohydric alcohol (G) having 10 or more carbon atoms, based on the total amount of the styrenic resin composition. Composition. The styrenic resin (A) is produced by reacting the styrene monomer (a1), the (meth)acrylic acid monomer unit (a2), and the 4-methoxyphenol and/or the hydroquinone as raw materials. The styrenic resin composition according to claim 1 or 2. A molded article made of the styrenic resin composition according to claim 1 or 2. A light guide made of the styrenic resin composition according to claim 1 or 2. A non-foamed extruded sheet having a thickness of 1 mm or less and comprising the styrenic resin composition according to claim 1 or 2. A foam extrusion sheet comprising the styrenic resin composition according to claim 1 or 2. An in-vehicle injection molded product obtained by injection molding the styrenic resin composition according to claim 1 or 2.