JP2022131823A - Styrenic resin composition and molded article - Google Patents

Abstract

To provide a styrenic resin composition excellent in heat resistance, oil resistance, ductility and surface appearance, and a molded article containing the styrenic resin composition.SOLUTION: The styrenic resin composition of the present invention contains 25-89 mass% of a styrenic resin (a) having an MFR of 5 or more, 10-55 mass% of cellulose (b), and 1-20 mass% of a rubbery polymer (c) modified with an unsaturated carboxylic acid compound.SELECTED DRAWING: None

Description

The present invention relates to a styrenic resin composition and molded articles.

Styrenic resins are used in a wide range of applications due to their excellent moldability, dimensional stability, and transparency. In addition, biomass materials have attracted attention from the viewpoint of environmental protection, and composite materials of resin materials and naturally-derived organic fillers or biopolymers are being studied.
For example, Patent Documents 1 and 2 describe a styrene-based composite resin composition comprising a styrene-based resin, a cellulose-based material, and a styrene-based thermoplastic elastomer, and Patent Document 3 describes a polystyrene-based resin containing acid-modified styrene and a cellulose-based material. A styrenic composite resin composition is disclosed.

JP-A-7-173352 Japanese Patent Application Laid-Open No. 2000-230105 JP-A-8-231795

However, in the techniques described in Patent Documents 1 and 2, although a large amount of cellulosic material can be blended with a styrene-based thermoplastic elastomer, spreadability is low due to insufficient dispersibility and interfacial adhesion of the cellulosic material. Furthermore, not only the sheet/film molded products of the styrene-based composite resin composition using the techniques of Patent Documents 1 and 2, but also the vacuum-molded products produced from the sheets/films have uneven thickness, and the strength of these molded products decreases. In addition to the decrease, there is a problem that the surface appearance is deteriorated. In addition, although the technique of Patent Document 3 can improve the dispersibility and interfacial adhesion of cellulosic materials with maleic anhydride-modified polystyrene, the material becomes brittle, resulting in a significant drop in extensibility and moldability. there was a point

Accordingly, an object of the present invention is to provide a styrene resin composition excellent in heat resistance, oil resistance, spreadability and surface appearance, and a molded article containing the styrene resin composition.

In view of the above problems, the present inventors have made intensive research and repeated experiments. The inventors have found that the above problems can be solved by using a resin composition in which the rubber-like polymer (c) modified with a derivative is mixed at a specific ratio, and have completed the present invention. That is, the present invention is as follows.

[1] The present invention comprises a styrene resin (a) having an MFR of 5 or more and 25 to 89% by mass,
10 to 55% by mass of cellulose (b),
A styrenic resin composition characterized by containing 1 to 20% by mass of a rubber-like polymer (c) modified with an unsaturated carboxylic acid or a compound.
[2] In the present invention, the rubber-like polymer (c) is preferably a maleic anhydride-modified styrenic rubber-like polymer.
[3] In the present invention, the cellulose (b) is preferably cellulose containing 20% by mass or less of lignin.
[4] In the present invention, the cellulose (b) is preferably cellulose containing 1% by mass or more of hemicellulose.
[5] The present invention is preferably a molded article containing the styrenic resin composition according to any one of [1] to [3] above.
[6] The present invention is preferably a sheet or film containing the styrenic resin composition according to any one of [1] to [4] above.

ADVANTAGE OF THE INVENTION According to this invention, the molded article containing the styrene resin composition and the said styrene resin composition which were excellent in heat resistance, oil resistance, spreadability, and surface appearance can be provided.

FIG. 1 is a schematic cross-sectional view of a mold used for a container, which is an example of the molded article of the present embodiment.

Hereinafter, embodiments of the present invention (hereinafter referred to as "present embodiments") will be described in detail. can be implemented.
[Styrene resin composition]
The styrene resin composition of the present embodiment comprises 25 to 89% by mass of styrene resin (a), 10 to 55% by mass of cellulose (b), and a rubber-like polymer modified with an unsaturated carboxylic acid or a compound. (c) 1 to 20% by mass. Moreover, the MFR of the styrene-based resin (a) is 5 or more.

<Styrene-based resin (a) (hereinafter also referred to as component (a))>
In the present embodiment, the content of the styrene resin (a) having an MFR of 5 or more is 25 to 89% by mass, preferably 30 to 85% by mass, with respect to the entire styrene resin composition (100% by mass). %, more preferably 35 to 83% by mass. By setting the content to 25% by mass or more, moldability and appearance can be improved. On the other hand, by setting the content to 89% by mass or less, the total content of cellulose (b) can be ensured, and heat resistance, oil resistance and the like can be improved.

It is necessary that the MFR (200° C., 5 kg) of the styrene resin (a) in the present invention is 5 or more. The MFR of the styrene resin (a) is preferably 8 or more, more preferably 10 or more and 30 or less, and still more preferably 10 or more and 25 or less.
In order to prevent coloring and burning of the cellulose (b) in the styrene resin composition of the present embodiment, it is necessary to melt-mix the constituent components of the composition at 240° C. or less. However, if the MFR of the styrene-based resin (a) is lower than 5, the cellulose (b) will be difficult to disperse in the styrene-based resin (a), resulting in reduced spreadability.
Furthermore, in order to improve adhesion with cellulose (b) and further improve spreadability, the styrene resin (a) contains styrene monomer units and unsaturated carboxylic acid monomer units. is preferred. The content of the unsaturated carboxylic acid-based monomer unit is preferably 2.0 to 16.0% by mass, more preferably 4 to 14% by mass, more preferably 4 to 14% by mass, based on the total styrene resin (a). is 8 to 13% by mass.
The styrene resin (a) to be used may be used by blending one or more kinds, and when the styrene resin (a) is a blend, the refractive index and MFR are the values of the blend. be.
MFR in this specification uses the value measured according to ISO 1133.

The styrene-based resin (a) that can be used in the present embodiment is preferably a polymer having styrene-based monomer units, more preferably a copolymer having styrene-based monomer units. The styrene resin (a) contains a styrene monomer and at least one monomer selected from other vinyl monomers and rubbery polymers copolymerizable with the styrene monomer. More preferably, it is a styrene-based copolymer resin obtained by polymerization. The styrene resin (a) in the present invention is not particularly limited. styrenic copolymer resin or a mixture thereof.

<<Polystyrene>>
In the present embodiment, polystyrene is a homopolymer obtained by polymerizing styrene-based monomers, and commonly available materials can be appropriately selected and used. Styrenic monomers constituting polystyrene include, in addition to styrene, α-methylstyrene, α-methyl-p-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethyl Styrene, isobutylstyrene, and styrene derivatives such as t-butylstyrene or bromostyrene and indene. The styrene-based monomer is preferably styrene from an industrial point of view. These styrenic monomers can be used singly or in combination of two or more. Polystyrene may contain further monomeric units other than the above styrene-based monomer units as long as the effect of the present invention is not impaired, but typically consists of styrene-based monomer units.

<<Rubber-modified styrene resin>>
In the present embodiment, the rubber-modified styrene resin is a polymer matrix in which particles of the rubber-like polymer (A) are dispersed in a styrene resin (including polystyrene and styrene-based copolymer resin). It can be produced by polymerizing a styrenic monomer in the presence of the polymer (A).

Examples of styrene-based monomers constituting the rubber-modified styrene-based resin of the present embodiment include styrene, α-methylstyrene, α-methyl p-methylstyrene, ο-methylstyrene, m-methylstyrene, Styrene derivatives such as p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, and t-butylstyrene or bromostyrene and indene. Styrene is particularly preferred. These styrenic monomers can be used singly or in combination of two or more.

The rubber-like polymer (A) contained in the rubber-modified styrenic resin of the present embodiment may, for example, enclose therein a styrene monomer unit-containing resin obtained from the above styrenic monomer, and /or a styrene monomer unit-containing resin may be grafted on the outside.

Examples of the rubber-like polymer (A) include polybutadiene, polybutadiene encapsulating polystyrene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and the like. Alternatively, a styrene-butadiene copolymer is preferred. Both high cis polybutadiene with a high cis content and low cis polybutadiene with a low cis content can be used for the polybutadiene. Both a random structure and a block structure can be used as the structure of the styrene-butadiene copolymer. One or more of these rubber-like polymers (A) can be used. Saturated rubber obtained by hydrogenating butadiene rubber can also be used.
Examples of such rubber-modified styrene resins 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) and the like.

In the present embodiment, when the rubber-modified styrenic resin is a HIPS resin, among these rubber-like polymers (A), particularly preferred is a high polymer composed of 90 mol % or more of cis-1,4 bonds. cis-polybutadiene. In the high-cis polybutadiene, the vinyl 1,2 bond is preferably 6 mol % or less, particularly preferably 3 mol % or less.
The content of isomers having a cis 1,4, trans 1,4, or vinyl 1,2 structure as isomers related to the structural units of the high-cis polybutadiene was measured using an infrared spectrophotometer and measured by the Morero method. It can be calculated by data processing.
The high-cis polybutadiene can be easily obtained by polymerizing 1,3-butadiene using a known production method, for example, a catalyst containing an organoaluminum compound and a cobalt or nickel compound.

In the present embodiment, the content of the rubber-like polymer (A) contained in the rubber-modified styrenic resin is preferably 2 to 10% by mass, more preferably 3% by mass, based on 100% by mass of the rubber-modified styrenic resin. ~8% by mass. If the content of the rubber-like polymer (A) is less than 2% by mass, the impact resistance of the styrene-based resin may decrease. Moreover, when the content of the rubber-like polymer (A) exceeds 10% by mass, the light transmittance may be lowered.
In the present disclosure, the content of the rubber-like polymer (A) contained in the rubber-modified styrenic resin is a value calculated using pyrolysis gas chromatography.

In the present embodiment, the average particle size of the rubber-like polymer (A) contained in the rubber-modified styrenic resin is preferably 0.5 to 2.5 μm, more preferably 0.5 to 2.5 μm from the viewpoint of light transmittance. 0.8 to 2.0 μm.
In addition, in the present disclosure, the average particle size of the rubber-like polymer (A) contained in the rubber-modified styrenic resin can be measured by the following method.
A 75 nm-thick ultra-thin section is prepared from a rubber-modified styrenic resin stained with osmium tetroxide, and photographed at a magnification of 10,000 using an electron microscope. In the photograph, black-stained particles are the rubber-like polymer. From the picture, the following formula (N1):
Average particle size = ΣniDri ³ /ΣniDri ² (N1)
(In the above formula (N1), ni is the number of rubber-like polymer (a) particles having a particle diameter Dri, and the particle diameter Dri is a particle diameter calculated as a circle-equivalent diameter from the area of the particles in the photograph. .)
The area-average particle size is calculated by the method and taken as the average particle size of the rubber-like polymer (A). For this measurement, a photograph is loaded into a scanner at a resolution of 200 dpi and measured using particle analysis software of an image analyzer IP-1000 (manufactured by Asahi Kasei Co., Ltd.).

In the present embodiment, the reduced viscosity of the rubber-modified styrenic resin (which is an index of the molecular weight of the rubber-modified styrenic resin) is preferably in the range of 0.50 to 0.85 dL/g, more preferably. is in the range of 0.55-0.80 dL/g. If it is less than 0.50 dL/g, the impact strength may decrease, and if it exceeds 0.85 dL/g, the fluidity may decrease, resulting in a decrease in moldability.
In the present disclosure, the reduced viscosity of the rubber-modified styrenic resin is a value measured in a toluene solution at 30° C. and a concentration of 0.5 g/dL.

In the present embodiment, the method for producing the rubber-modified styrenic resin is not particularly limited. or solution polymerization), or bulk-suspension polymerization that shifts to suspension polymerization during the reaction, or emulsion graft polymerization that polymerizes a styrene-based monomer in the presence of a rubber-like polymer (A) latex. can be done. In bulk polymerization, a mixed solution containing a rubber-like polymer (a), a styrenic monomer, and optionally an organic solvent, an organic peroxide, and/or a chain transfer agent is added to a complete mixing reactor. Alternatively, it can be produced by continuously supplying to a polymerization apparatus constructed by connecting a tank reactor and a plurality of tank reactors in series.

<<Styrene-based copolymer resin>>
In the present embodiment, the styrene copolymer resin is a resin containing styrene monomer units and unsaturated carboxylic acid monomer units and/or unsaturated carboxylic acid ester monomer units. In the styrene copolymer resin of the present invention, when the total content of styrene monomer units, unsaturated carboxylic acid monomer units, and unsaturated carboxylic acid ester monomer units is 100% by mass, The content of styrenic monomer units is preferably 69 to 98% by mass, more preferably 74 to 96% by mass, still more preferably 77 to 92% by mass. By setting the content to 69% by mass or more, the refractive index of the styrene-based resin (a) can be improved. On the other hand, by setting the content to 98% by mass or less, it becomes difficult to allow desired amounts of unsaturated carboxylic acid-based monomer units and optional unsaturated carboxylic acid ester-based monomer units to be described later. It becomes difficult to obtain the effect described later by the monomer unit of.

In the styrene-based copolymer resin of the present embodiment, the unsaturated carboxylic acid-based monomer unit plays a role of improving heat resistance. When the total content of styrene-based monomer units, unsaturated carboxylic acid-based monomer units, and unsaturated carboxylic acid ester-based monomer units in the styrene-based copolymer resin is 100% by mass, unsaturated carboxylic acid The content of acid monomer units is preferably 2 to 16% by mass, more preferably 4 to 14% by mass, still more preferably 8 to 13% by mass. By setting the content to 2% by mass or more, the dispersibility of cellulose can be improved, and the light transmittance, appearance, and heat resistance can be further improved. On the other hand, by setting the content to 16% by mass or less, the fluidity and mechanical properties of the resin can be improved.

In general, styrene-methacrylic acid-based resins including styrene-methacrylic acid-methyl methacrylate copolymer resins, which are examples of styrene-based copolymer resins, are produced by radical polymerization in most cases on an industrial scale. In this embodiment, polymerization can be carried out by adding various alcohols to the polymerization system in order to suppress the gelling reaction in the devolatilization step.

The unsaturated carboxylic acid ester-based monomer suppresses the dehydration reaction of the unsaturated carboxylic acid-based monomer through intermolecular interaction with the unsaturated carboxylic acid-based monomer, and the mechanical strength of the resin can be used to improve Furthermore, the unsaturated carboxylic acid ester monomer contributes to the improvement of resin properties such as weather resistance and surface hardness.

In the styrene-based copolymer resin of the present embodiment, when the total content of the styrene-based monomer unit, the unsaturated carboxylic acid-based monomer unit, and the unsaturated carboxylic acid ester-based monomer unit is 100% by mass , the content of unsaturated carboxylic acid ester-based monomer units is preferably 0 to 15% by mass, more preferably 1 to 12% by mass, and still more preferably 2 to 10% by mass. By setting the content to 15% by mass or less, the light transmittance and fluidity of the resin can be improved. In addition, by setting the content of the unsaturated carboxylic acid ester-based monomer unit to 0% by mass, it is possible to improve heat resistance and reduce costs, but from the above viewpoint, the unsaturated carboxylic acid ester-based monomer The body unit content can also be greater than 0% by weight.

When an unsaturated carboxylic acid-based monomer and an unsaturated carboxylic acid ester-based monomer unit are bonded side by side, if a high-temperature, high-vacuum devolatilization apparatus is used, a dealcoholization reaction may occur depending on the conditions. Six-membered cyclic anhydrides may be formed. Although the copolymer resin of the present embodiment may contain this six-membered cyclic anhydride, it is preferable that the amount of the six-membered cyclic anhydride produced is as small as possible because it reduces fluidity.

In the present embodiment, styrene monomer units (e.g., styrene monomer units), unsaturated carboxylic acid-based monomer units (e.g., methacrylic acid monomer units) and unsaturated The content of the carboxylic acid ester-based monomer unit (eg, methyl methacrylate monomer unit) can be determined from the integral ratio of the spectrum measured with a proton nuclear magnetic resonance ( ¹ H-NMR) spectrometer. .

In the present embodiment, the styrene copolymer resin includes styrene monomer units, unsaturated carboxylic acid monomer units, and monomer units other than the optional unsaturated carboxylic acid ester monomer units. is not excluded as long as it does not impair the effects of the present invention. However, the copolymer resin in the present invention is typically preferably composed of styrene-based monomer units, unsaturated carboxylic acid-based monomer units, and unsaturated carboxylic acid ester-based monomer units. .

Examples of the styrene-based monomer constituting the styrene-based copolymer resin of the present embodiment include, but are not limited to, styrene, α-methylstyrene, α-methyl-p-methylstyrene, Styrene derivatives such as ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, t-butylstyrene, bromostyrene, and indene. As the styrene-based monomer, styrene is preferable from an industrial point of view. These styrenic monomers can be used singly or in combination of two or more.

The unsaturated carboxylic acid-based monomer constituting the styrene-based copolymer resin of the present embodiment is not particularly limited, but examples thereof include methacrylic acid, acrylic acid, maleic anhydride, maleic acid, fumaric acid, and itaconic acid. be done. As the unsaturated carboxylic acid-based monomer, methacrylic acid is preferable because it has a large effect of improving heat resistance and is liquid at room temperature and excellent in handleability. These unsaturated carboxylic acid-based monomers can be used singly or in combination of two or more.

The unsaturated carboxylic acid ester-based monomer constituting the styrene-based copolymer resin of the present embodiment is not particularly limited, but examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. , butyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like. As the (meth)acrylic acid ester-based monomer, methyl (meth)acrylate is preferable because it has little effect on deterioration of heat resistance. These unsaturated carboxylic acid ester monomers can be used singly or in combination of two or more.
Examples of the styrene-based copolymer resin of the present embodiment include styrene-methyl (meth)acrylate copolymer, styrene-ethyl (meth)acrylate copolymer, styrene-propane (meth)acrylate copolymer, or styrene -Butyl (meth)acrylate copolymer, styrene-methyl (meth)acrylate-butyl methacrylate copolymer, and styrene-methyl (meth)acrylate-methacrylic acid copolymer are preferred.

In the present embodiment, the weight average molecular weight (Mw) of the styrenic copolymer resin is preferably 100,000 to 350,000, more preferably 120,000 to 300,000, still more preferably 140,000 to 240. , 000. When the weight-average molecular weight (Mw) is from 100,000 to 350,000, a resin having excellent balance between mechanical strength and fluidity can be obtained, and gel matter is less mixed. The weight average molecular weight (Mw) is a value obtained by standard polystyrene conversion using gel permeation chromatography.

As the styrene resin (a) of the present embodiment, a mixture obtained by blending one or more of the rubber-modified styrene resins and one or more of the styrene copolymer resins may be used. good. In that case, the mixing ratio of the rubber-modified styrenic resin and the styrenic copolymer resin can be appropriately changed according to the purpose of use. For example, in a system in which the rubber-modified styrene resin is less than the styrene copolymer resin, the styrene copolymer resin is contained in an amount of 0.1 to 30% by mass with respect to the total amount (100% by mass) of the styrene resin (a). preferably. On the other hand, in a system in which the rubber-modified styrene resin is more than the styrene copolymer resin, the styrene copolymer resin is contained in an amount of 70 to 99.9% by mass with respect to the total amount (100% by mass) of the styrene resin (a). preferably.

In the present embodiment, the method for polymerizing the styrene-based copolymer resin is not particularly limited, but for example, a bulk polymerization method or a solution polymerization method can be suitably employed as a radical polymerization method. The polymerization method mainly includes a polymerization step of polymerizing raw materials for polymerization (monomer components) and a devolatilization step of removing volatile matter such as unreacted monomers and polymerization solvent from the polymerization product.
An example of a method for polymerizing a styrene-based copolymer resin that can be used in the present embodiment will be described below.
When the raw material for polymerization is polymerized to obtain the styrenic copolymer resin, the raw material composition for polymerization is typically made to contain a polymerization initiator and a chain transfer agent.
Polymerization initiators used for polymerization of styrene copolymer resins include organic peroxides such as 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, n -Peroxyketals such as butyl-4,4-bis(t-butylperoxy)valerate, dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, acetyl peroxide, isobutyryl Examples include diacyl peroxides such as peroxides, peroxydicarbonates such as diisopropylperoxydicarbonate, peroxyesters such as t-butylperoxyacetate, ketone peroxides such as acetylacetone peroxide, and hydroperoxides such as t-butyl hydroperoxide. be able to. Among them, 1,1-bis(t-butylperoxy)cyclohexane is preferred from the viewpoint of decomposition rate and polymerization rate.
Chain transfer agents used for polymerization of styrene copolymer resins include, for example, α-methylstyrene linear dimer, n-dodecylmercaptan, t-dodecylmercaptan, n-octylmercaptan and the like.

As a method for polymerizing the styrene-based copolymer resin, solution polymerization using a polymerization solvent can be employed as necessary. Examples of the polymerization solvent to be used include aromatic hydrocarbons such as ethylbenzene and dialkyl ketones such as methyl ethyl ketone, each of which may be used alone or in combination of two or more. Other polymerization solvents such as aliphatic hydrocarbons can be further mixed with the aromatic hydrocarbons as long as they do not reduce the solubility of the polymerization product. These polymerization solvents are preferably used in an amount not exceeding 25 parts by mass with respect to 100 parts by mass of the total monomers. If the amount of the polymerization solvent exceeds 25 parts by mass with respect to 100 parts by mass of the total monomers, the polymerization rate tends to decrease significantly and the mechanical strength of the resulting resin tends to decrease significantly. Addition of 5 to 20 parts by mass per 100 parts by mass of all monomers prior to polymerization facilitates homogenization of quality and is also preferable from the viewpoint of polymerization temperature control.

In the present embodiment, the apparatus used in the polymerization step for obtaining the styrene-based copolymer resin is not particularly limited, and may be appropriately selected according to the polymerization method of the styrene-based resin. For example, when bulk polymerization is employed, a polymerization apparatus in which one or a plurality of complete mixing reactors are connected can be used. Also, the devolatilization step is not particularly limited. For example, when adopting bulk polymerization, the unreacted monomer is preferably 50% by mass or less, more preferably 40% by mass or less. Then, it is devolatilized by a known method. More specifically, for example, a flash drum, a twin-screw devolatilizer, a thin-film evaporator, an extruder, or other ordinary devolatilizer can be used, but a devolatilizer with a small stagnant portion is preferred. The temperature of the devolatilization treatment is usually about 190 to 280° C., and more preferably 190 to 260° C. from the viewpoint of suppressing the formation of a six-membered cyclic acid anhydride due to the adjacency of methacrylic acid and methyl methacrylate. . The pressure of the devolatilization treatment is usually about 0.13 to 4.0 kPa, preferably 0.13 to 3.0 kPa, more preferably 0.13 to 2.0 kPa. Desirable devolatilization methods include, for example, a method of reducing the pressure under heating to remove the volatile matter, and a method of removing the volatile matter through an extruder or the like designed for the purpose of removing the volatile matter.

<Cellulose (b) (hereinafter also referred to as component (b))>
The content of cellulose (b) in the present embodiment is 10 to 55% by mass, preferably 20 to 52% by mass, more preferably 30 to 50% by mass. By setting the content of cellulose (b) to 10% by mass or more, heat resistance and oil resistance can be improved. On the other hand, if the content is more than 50% by mass, not only is the ductility lowered, but also the moldability is remarkably lowered due to the lowered fluidity. The cellulose content in the composition can be found by dissolving the composition in a solvent that dissolves the styrene resin, taking out the undissolved matter, and measuring the mass of the matter dried at 120° C. for 4 hours.

In the present embodiment, at least one of the average length of the short axis d1 or the long axis d2 of cellulose (b) is 0.03 to 80 μm, preferably 0.05 to 60 μm, preferably 0.1 to 50 μm, more preferably 0.2 to 30 μm. If the average length of the short axis and long axis is outside the above range, the heat resistance may not be sufficiently exhibited, or the impact resistance and molding appearance may deteriorate. On the other hand, when the average length of the short axis and long axis of cellulose (b) is within the above range, the aggregation of cellulose can be reduced, and the dispersibility in the styrene resin (a) is good, and the light transmittance is improved. improves.
In the present invention, the average length d ₁ of the short axis of cellulose (b) is the short axis length (minimum length) of 100 cellulose (b) by transmission electron microscope observation (magnified by 5000 times). It is obtained by measuring and taking the arithmetic mean. Similarly, the average length of the long axis of cellulose is obtained by measuring the long axis length (maximum length) of 100 celluloses (b) by transmission electron microscopy (magnified by 5000 times) and taking the arithmetic mean. It is required by In addition, the short axis length (minimum length) of cellulose (b) refers to the length of the thinnest (or shortest) point on the image observed with a transmission electron microscope (magnified 5000 times), and cellulose (b) ) refers to the length of the longest point on the image. The light transmittance is affected by the shape of cellulose, and in the case of fibers, the average diameter of the short axis and the average diameter of the long axis of scaly or granular fibers.
The shape of the cellulose (b) in the present invention is not particularly limited, and examples thereof include spherical, irregular, powdery, scaly, fibrous and rod-like shapes.
The aspect ratio (d ₁ /d ₂ ) of cellulose (b) in the present invention is preferably 1 to 500, more preferably 1.2 to 300, and further preferably 1.5 to 200. 2 to 100 are particularly preferred.

Cellulose (b) in the present invention refers to polysaccharides having a β-1,4-glucan structure, and includes cellulose and hemicellulose. In addition, the material of cellulose (b) is not particularly limited as long as the fibers constituting it are formed of a polysaccharide having a β-1,4-glucan structure. Cellulose fibers [e.g., wood fibers (wood pulp of softwoods, hardwoods, etc.), bamboo fibers, sugarcane fibers, seed hair fibers (cotton linter, bombax cotton, kapok, etc.), ginskin fibers (e.g., hemp, paper mulberry, mitsumata, etc.), natural cellulose fibers (pulp fibers) such as leaf fibers (e.g., Manila hemp, New Zealand hemp, etc.), animal-derived cellulose fibers (sea squirt cellulose, etc.), bacterial-derived cellulose fibers, regenerated cellulose (rayon, cellophane, etc.) )] and the like. You may use these fibers which comprise a cellulose (b) individually or in combination of 2 or more types.

Among the fibers constituting the cellulose (b), the production efficiency is high in terms of dispersibility, rigidity, and impact resistance when the cellulose (b) is produced, and the plant has an appropriate fiber diameter and fiber length. Cellulose fibers derived from pulp, such as wood fibers (wood pulps of softwood, hardwood, bamboo, etc.) and seed hair fibers (cotton linter pulp, etc.), are preferred.
Furthermore, in the present embodiment, hemicellulose is preferably contained in an amount of 1% by mass or more based on cellulose (b). By containing hemicellulose, the dispersibility with the styrene resin (a) is improved, and the light transmittance, rigidity, and molding appearance can be improved. In the present invention, it is preferable that these components are not completely removed in the cellulose manufacturing process, but are left in a suitable range of content. Hemicellulose is a polysaccharide composed of sugars such as mannan and xylan, and plays a role in binding microfibrils by forming hydrogen bonds with cellulose. In addition, since the solubility parameter (SP value) of hemicellulose is on the more hydrophobic side than cellulose, hemicellulose is thought to have the effect of alleviating the SP value difference between styrene resin (a) and cellulose (b). be done. The amount of hemicellulose can be adjusted to a desired amount by subjecting natural wood raw materials with a high hemicellulose content to a refining treatment. A desired amount can be adjusted by adding hemicellulose obtained by extraction from another raw material. At this time, the structure of hemicellulose, such as terminal ends, may be partially different from the natural product due to purification or extraction treatment.
In the present embodiment, for the purpose of alleviating the SP value difference between the styrene-based resin (a) and the cellulose (b), hemicellulose is 1% by mass or more and 25% by mass with respect to the cellulose (b) (100% by mass). It is more preferably contained below, more preferably 2% by mass or more and 20% by mass or less, even more preferably 3% by mass or more and 20% by mass or less, and 5% by mass or more and 19.5% by mass or less. Even more preferably, it is particularly preferable to contain 7% by mass or more and 19.3% by mass or less.

In the present embodiment, lignin is preferably 20% by mass or less, more preferably 10% by mass or less, relative to cellulose (b). If the lignin content is more than 20% by mass, the rubber-like polymer (c) modified with an unsaturated carboxylic acid or its anhydride or a derivative thereof reacts with lignin, resulting in dispersibility of cellulose and adhesiveness with cellulose. becomes insufficient, resulting in reduced ductility and increased odor and coloration during heat processing.

<Rubber-like polymer (c) modified with an unsaturated carboxylic acid compound (hereinafter also referred to as component (c))>
The rubber-like polymer (c) of the present invention can be used without particular limitation as long as it is a rubber-like polymer modified with an unsaturated carboxylic acid compound. In other words, the rubber-like polymer (c) of the present invention is obtained by modifying the rubber-like polymer (D) with an unsaturated carboxylic acid compound.

The rubber-like polymer (D) includes polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, polyacrylate, styrene-butadiene block copolymer, styrene-butadiene-styrene copolymer, styrene-isoprene block copolymer. Polymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-butadiene-styrene Block copolymer, hydrogenated styrene-isoprene block copolymer, hydrogenated styrene-isoprene-styrene block copolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-α olefin copolymer , ethylene-propylene-ethylidene norbornene copolymer, ethylene-vinyl acetate copolymer, linear low-density polyethylene elastomer, acrylic elastomer, polyester/polyether co-elastomer, polyamide elastomer and the like. Among them, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene copolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-α-olefin copolymer, ethylene-propylene- Ethylidene norbornene copolymers are preferred.

Examples of the unsaturated carboxylic acid-based compound that modifies the rubber-like polymer (D) include unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and derivatives thereof. Examples of the unsaturated carboxylic compounds include maleic acid, fumaric acid, itaconic acid, methylmaleic acid, 3,6-endomethylene-delta-4-tetrahydrophthalic acid, acrylic acid, methacrylic acid, crotonic acid, citraconic acid, anhydrous maleic acid, itaconic anhydride, methyl maleic anhydride, 3,6-endomethylene-delta-4-tetrahydrophthalic anhydride, 2-methyl-3,6-endomethylene-delta-4-tetrahydrophthalic anhydride, Derivatives such as 3-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, glycidyl acrylate, glycidyl methacrylate, and alkyl cyanoacrylate having 1 to 20 carbon atoms can be mentioned. Among them, the unsaturated carboxylic compound is preferably maleic acid or maleic anhydride. As a method for modifying the rubber-like polymer (D) with an unsaturated carboxylic acid compound, a known method can be employed. For example, an unsaturated carboxylic acid or the like is graft-polymerized to the rubber-like polymer (D). method.

Specific examples of the rubber-like polymer (c) of the present invention include maleic acid-modified styrene-ethylene-butylene-styrene copolymer, maleic acid-modified styrene-ethylene-propylene copolymer, and maleic acid-modified ethylene-propylene. Copolymers, maleic acid-modified ethylene-1-butene copolymers, maleic acid-modified ethylene-α-olefin copolymers, maleic acid-modified ethylene-propylene-ethylidene norbornene copolymers, maleic anhydride-modified styrene-ethylene-butylene- Styrene copolymer, maleic anhydride-modified styrene-ethylene-propylene copolymer, maleic anhydride-modified ethylene-propylene copolymer, maleic anhydride-modified ethylene-1-butene copolymer, maleic anhydride-modified ethylene-α olefin copolymers, maleic anhydride-modified ethylene-propylene-ethylidenenorbornene copolymers, and the like. The rubber-like polymer (c) can be used alone or in combination of two or more.

<Optional Addition Ingredients>
In addition to the above components (a) to (c), the styrenic resin composition of the present embodiment includes, if necessary, additives such as known additives and processing aids within a range that does not impair the effects of the present invention. can be added. Examples of these additives, processing aids, etc. include dispersants, antioxidants, weathering agents, antistatic agents, fillers, and the like.
<Dispersant>
In this embodiment, a dispersant may be contained in the styrene-based resin composition for the purpose of improving the dispersibility of the cellulose (b). By adding a dispersant to the styrenic resin composition, it is possible to prevent burning or eye mucus (so-called molten resin residue) of the extruder used when combining the cellulose (b) and the styrenic resin (a). and the molded appearance can be further improved. If the amount of the dispersant is less than the predetermined amount, no significant effect can be expected, and if the amount is more than the predetermined amount, it is difficult to obtain high heat resistance. A dispersant having excellent affinity with the styrene-based resin (a) tends to exhibit a greater effect.

In this embodiment, a fatty acid ester compound, a polyethylene glycol compound, a terpene compound, a rosin compound, a fatty acid amide, a fatty acid compound, or a fatty acid metal salt can be used as the dispersant. In particular, the dispersant is preferably one or more compounds selected from the group consisting of fatty acid ester compounds, polyethylene glycol compounds, terpene compounds, and rosin compounds.
Examples of the aliphatic ester compounds include methyl laurate, methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl erucate, methyl behenate, butyl laurate, butyl stearate, isopropyl myristate, palmitin. isopropyl acid, octyl palmitate, coconut fatty acid octyl ester, octyl stearate, beef tallow fatty acid octyl ester, lauryl laurate, stearyl stearate, behenyl behenate, cetyl myristate, linear unbranched chain with 28-30 carbon atoms Ester of saturated monocarboxylic acid (hereinafter abbreviated as montanic acid) and ethylene glycol, ester of montanic acid and glycerol, ester of montanic acid and butylene glycol, ester of montanic acid and trimethylolethane, ester of montanic acid and trimethylolpropane , esters of montanic acid and pentaerythritol, glycerin monostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, Polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate and the like. These may be used alone or in combination of two or more.
The polyethylene glycol-based compound is not particularly limited, and examples thereof include polyethylene glycols, polypropylene glycols, polyethylene glycol alkyl ethers, polypropylene glycol alkyl ethers, polyethylene glycol aryl ethers, polypropylene glycol aryl ethers, polyethylene glycol alkyl aryl ethers, polypropylene glycol alkyl aryl ethers, polyethylene glycol glycerin esters, polypropylene glycol glycerin esters, polyethylene sorbitol esters, polypropylene glycol sorbitol esters, polyethylene glycol ethylenediamines, polypropylene glycol ethylenediamines, polyethylene glycol diethylenetriamines and polypropylene-glycolized diethylenetriamines.

As the terpene-based resin, a terpene monomer alone, or a terpene monomer and an aromatic monomer, or a terpene monomer and a phenol are usually copolymerized in an organic solvent in the presence of a Friedel-Crafts type catalyst. However, it is not limited to these. Examples of the terpene monomer include hemiterpenes having 5 carbon atoms such as isoprene, α-pinene, β-pinene, dipentene, d-limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, and γ-terpinene. , terpinolene, 1,8-cineole, 1,4-cineol, α-terpineol, β-terpineol, γ-terpineol, sabinene, paramentadienes, monoterpenes having 10 carbon atoms such as carenes, caryophyllene, longifolene, etc. sesquiterpenes having 15 carbon atoms, diterpenes having 20 carbon atoms, and the like, but are not limited thereto. Among these compounds, α-pinene, β-pinene, dipentene and d-limonene are particularly preferably used. Examples of the aromatic monomer include, but are not limited to, styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, and the like. The phenols include phenol, cresol, xylenol, bisphenol A and the like, but are not limited to these.
Moreover, the hydrogenated terpene-based resin obtained by hydrogenating the obtained terpene-based resin may be used. For example, preferred terpene-based resins include terpene-based resins such as α-pinene resin, β-pinene resin, aromatic modified terpene resin, terpene phenolic resin, and hydrogenated terpene resin. The terpene-based resins may be used alone or in combination of two or more.

Examples of the rosin-based resin include, in addition to rosins such as gum rosin, wood rosin, and tall oil rosin, stabilized rosins obtained by disproportionating or hydrogenating the above rosins, and polymerized rosins that are multimers of the above rosins (typically is a dimer), modified rosins modified with unsaturated acids such as maleic acid, fumaric acid and (meth)acrylic acid. Examples of rosin derivative resins include esterified products of the above rosin resins, phenol-modified products, esterified products thereof, and the like. The rosin-based resins may be used singly or in combination of two or more. The rosin-based resin or rosin derivative resin used in the present invention is not limited to these resins.

Examples of the aliphatic amide include stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, ethylene bis stearic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, and ethylene bis lauric acid amide. . These may be used alone or in combination of two or more.

Specific examples of saturated fatty acids among the above fatty acid compounds include lauric acid (dodecanoic acid), isodecanoic acid, tridecylic acid, myristic acid (tetradecanoic acid), pentadecylic acid, palmitic acid (hexadecanoic acid), margaric acid (heptadecane acid), stearic acid (octadecanoic acid), isostearic acid, tubercrostearic acid (nonadecanic acid), 2-hydroxystearic acid, arachidic acid (icosanoic acid), behenic acid (docosanoic acid), lignoceric acid (tetradocosanoic acid), serotin acid (hexadocosanoic acid), montanic acid (octadocosanoic acid), melissic acid and the like, particularly lauric acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid and montanic acid. These may be used alone or in combination of two or more.

Among the above fatty acid compounds, unsaturated fatty acids include, specifically, myristoleic acid (tetradecenoic acid), palmitoleic acid (hexadecenoic acid), oleic acid (cis-9-octadecenoic acid), elaidic acid (trans-9- octadecenoic acid), ricinoleic acid (octadecadienoic acid), vaccenic acid (cis-11-octadecenoic acid), linoleic acid (octadecadienoic acid), linolenic acid (9,11,13-octadecatrienoic acid), elestearin acid (9,11,13-octadecatrienoic acid), gadoleic acid (icosanoic acid), erucic acid (docosanoic acid), nervonic acid (tetradocosanoic acid) and the like. These may be used alone or in combination of two or more.

Examples of fatty acid metal salts include lithium salts, calcium salts, magnesium salts, zinc salts, and aluminum salts of fatty acids of the above fatty acid compounds. These may be used alone or in combination of two or more.

Examples of the antioxidant include phenol compounds, phosphorus compounds, thioether compounds, and the like.
Examples of the phenolic antioxidant include 2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, distearyl (3,5-di-tert-butyl -4-hydroxybenzyl)phosphonate, 1,6-hexamethylenebis[(3,5-di-tertbutyl-4-hydroxyphenyl)propionamide], 4,4′-thiobis(6-tert-butyl-m -cresol), 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 2,2′-methylenebis(4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis(6-tert -butyl-m-cresol), 2,2′-ethylidenebis(4,6-di-tert-butylphenol), 2,2′-ethylidenebis(4-sec-butyl-6-tert-butylphenol), 1, 1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl)isocyanurate , 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 2-tert-butyl-4-methyl-6-(2-acryloyloxy-3-tert-butyl-5-methylbenzyl)phenol, stearyl [3-(3,5- di-tert-butyl-4-hydroxyphenyl) propionate], tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) methyl propionate] methane, thiodiethylene glycol bis [(3,5-di -tert-butyl-4-hydroxyphenyl)propionate], 1,6-hexamethylenebis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis[3,3-bis(4- hydroxy-3-tert-butylphenyl)butyric acid]glycol ester, bis[2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl]terephthalate, 1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate, 3,9-bis[1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5 ,5]undecane, triethylene glycol bis[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] and the like. These may be used singly or in combination of two or more.

Examples of the phosphorus antioxidant include tris(2,4-di-tert-butylphenyl)phosphite, trisnonylphenylphosphite, tris[2-tert-butyl-4-(3-tert-butyl- 4-hydroxy-5-methylphenylthio)-5-methylphenyl]phosphite, tridecylphosphite, octyldiphenylphosphite, di(decyl)monophenylphosphite, di(tridecyl)pentaerythritol diphosphite, di( nonylphenyl)pentaerythritol diphosphite, bis(2,4-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis (2,4,6-tri-tert-butylphenyl) pentaerythritol diphosphite, bis(2,4-dicumylphenyl) pentaerythritol diphosphite, tetra(tridecyl)isopropylidene diphenol diphosphite, tetra( tridecyl)-4,4′-n-butylidenebis(2-tert-butyl-5-methylphenol) diphosphite, hexa(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-tert- butylphenyl)butane triphosphite, tetrakis(2,4-di-tert-butylphenyl)biphenylenediphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2 '-methylenebis(4,6-tert-butylphenyl)-2-ethylhexylphosphite, 2,2'-methylenebis(4,6-tert-butylphenyl)-octadecylphosphite, 2,2'-ethylidenebis(4 ,6-di-tert-butylphenyl)fluorophosphite, tris(2-[(2,4,8,10-tetrakis-tert-butyldibenzo[d,f][1,3,2]dioxaphosphite Pin-6-yl)oxy]ethyl)amine, phosphite of 2-ethyl-2-butylpropylene glycol and 2,4,6-tri-tert-butylphenol and the like. These may be used singly or in combination of two or more.

Examples of the thioether antioxidant include dialkyl thiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, and pentaerythritol tetra(β-alkylmercaptopropionate). These may be used singly or in combination of two or more.

As the weather resistant agent, an ultraviolet absorber, a hindered amine light stabilizer, and the like can be used. Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5′-methylenebis(2-hydroxy-4-methoxybenzophenone ) and other 2-hydroxybenzophenones; 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-5- Chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert -octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole, 2,2'-methylenebis(4-tert-octyl-6-(benzotriazolyl) ) phenol), 2-(2′-hydroxyphenyl)benzotriazoles such as 2-(2′-hydroxy-3′-tert-butyl-5′-carboxyphenyl)benzotriazole; phenyl salicylate, resorcinol monobenzoate, 2 ,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2,4-di-tert-amylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate , hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate and other benzoates; 2-ethyl-2'-ethoxyoxaanilide, 2-ethoxy-4'-dodecyloxanilide and other substituted oxanilides cyanoacrylates such as ethyl-α-cyano-β, β-diphenylacrylate, methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate; 2-(2-hydroxy-4-octoxy phenyl)-4,6-bis(2,4-di-tert-butylphenyl)-s-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-s-triazine, 2- triaryltriazines such as (2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-di-tert-butylphenyl)-s-triazine; These may be used singly or in combination of two or more.

Examples of the hindered amine light stabilizer include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2, 6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-tetramethyl-4-piperidyl) Sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4 -butane tetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butane tetracarboxylate, bis(2,2,6,6-tetramethyl -4-piperidyl).di(tridecyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl).di(tridecyl)-1, 2,3,4-butanetetracarboxylate, bis(1,2,2,4,4-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-t-butyl-4-hydroxy benzyl)malonate, 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol/diethyl succinate polycondensate, 1,6-bis(2,2,6,6 -tetramethyl-4-piperidylamino)hexane/2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino) Hexane/2,4-dichloro-6-t-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(2,2,6 ,6-tetramethyl-4-piperidyl)amino)-s-triazin-6-yl]-1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis[2,4-bis( N-Butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazin-6-yl]-1,5,8-12-tetraazadodecane, 1,6 ,11-tris[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazin-6-yl]aminoundecane, 1,6 , 11-tris[2,4-bis(N-butyl-N-(1,2, 2,6,6-Pentamethyl-4-piperidyl)amino)-s-triazin-6-yl]aminoundecane and other hindered amine compounds. These may be used singly or in combination of two or more.

Cationic, anionic, nonionic, amphoteric, and fatty acid partial esters such as glycerin fatty acid monoester can be used as the antistatic agent.
Specifically, alkyltrimethylammonium salts, dialkyldimethylammonium salts, benzalkonium salts, N,N-bis(2-hydroxyethyl)-N-(3-dodecyloxy-2-hydroxypropyl)methylammonium mesosulphate , (3-laurylamidopropyl)trimethylammonium methylsulfate, stearamidopropyldimethyl-2-hydroxyethylammonium nitrate, stearamidopropyldimethyl-2-hydroxyethylammonium phosphate, cationic polymer, alkylsulfonate , Alkyl benzene sulfonate, Sodium alkyl diphenyl ether disulfonate, Alkyl nitrate ester salt, Phosphate alkyl ester salt, Alkyl phosphate amine salt, Stearate monoglyceride, Pentaerythritol fatty acid ester, Sorbitan monopalmitate, Sorbitan monostearate, Diglycerin fatty acid Esters, alkyldiethanolamines, alkyldiethanolamine fatty acid monoesters, alkyldiethanolamides, polyoxyethylene dodecyl ethers, polyoxyethylene alkylphenyl ethers, polyethylene glycol monolaurates, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyether block copolymers , cetyl betaine, hydroxyethylimidazoline sulfate, and the like. These may be used singly or in combination of two or more.

Talc, calcium carbonate, barium sulfate, carbon fiber, mica, wollastonite, whiskers and the like can be used as the filler.
In addition, anti-blocking agents, coloring agents, anti-blooming agents, surface treatment agents, antibacterial agents, anti-stain agents (silicone oil described in JP-A-2009-120717, monoamide compounds of higher aliphatic carboxylic acids, and higher fatty acid An anti-mucus agent such as a monoester compound obtained by reacting a group carboxylic acid with a monohydric to trihydric alcohol compound may be added.

The total content of optional components such as additives and processing aids may be 0.05 to 5% by mass in the styrenic resin composition.

The styrenic resin composition of the present embodiment may consist essentially of components (a) to (c) and optional additive components. Further, it may consist of only components (a) to (c), or only components (a) to (c) and optional additional components.
"Consisting essentially of components (a) to (c) and optional additional components" means that 95 to 100% by mass (preferably 98 to 100% by mass) of the styrene resin composition is (a) to It means that it is a component (c), or it is a component (a) to (c) and an optional additive component.
The styrenic resin composition of the present embodiment may contain unavoidable impurities in addition to components (a) to (c) and optionally added components within a range that does not impair the effects of the present invention.

[Physical properties of styrene resin composition]
<Heat resistance>
Regarding the heat shrinkage rate of the molded body obtained from the styrene resin composition of the present embodiment, the absolute value of the change in length before and after standing for 30 minutes in an atmosphere of 120 ° C. is preferably 10% or less. More preferably, it is 5% or less. If the absolute value of the variation in length exceeds 10%, the product may be deformed. Moreover, the heat shrinkage ratio is represented by the following formula (1).
Heat shrinkage =|(db-da)/da| formula (1)
(In the above formula (1), da represents the length in the longitudinal direction of the ISO test piece before standing for 30 minutes in an atmosphere of 120 ° C. db represents the length of the ISO test piece after standing for 30 minutes in an atmosphere of 120 ° C. represents the length in the long axis direction.)

<Oil resistance>
The oil resistance of the molded article obtained from the styrene-based resin composition of the present embodiment is preferably such that no change in appearance is observed when oil such as salad oil is applied.

<Delasticity>
The ductility of the styrene-based resin composition of the present embodiment is obtained when a container is formed with a predetermined drawing ratio,
Refers to the ratio of bottom sidewall thickness/top sidewall thickness of the container. It is preferable that a container having a drawing ratio of 0.5 or more can be obtained by vacuum forming a sheet body, which is a molded article formed from the styrene-based resin composition of the present embodiment. The malleability in this embodiment is preferably such that the ratio of the thickness of the bottom side wall/thickness of the top side wall after vacuum forming a container with a drawing ratio of 0.5 is 1 to 0.3.
As an example of the molded body of this embodiment, molding of a container will be described with reference to FIG. FIG. 1 is a cross-sectional view of a mold 1 required for molding a container. Moreover, in FIG. 1, the state which has mounted the spacer 2 of 80 cm in height on the bottom of the metal mold|die 1 is shown as an example. The height of the spacer 2 can be appropriately adjusted according to the desired height of the container.
For example, as a method for manufacturing the container of the present embodiment, a sheet of a styrene-based resin composition is prepared by extruding a styrene-based resin composition prepared according to the composition described below. After that, the obtained sheet of the styrene resin composition is preheated at 150 to 250 ° C. for 5 to 60 seconds, and then the heated sheet is placed so as to cover the recess of the mold 1, and a predetermined molding method is performed. Shaped by For example, the desired shape of the container can be formed by applying a vacuum to the recess.
Alternatively, after placing the sheet body so as to cover the concave portion of the mold 1, the sheet body may be heated and shaped by a predetermined molding method (for example, thermocompression molding, vacuum molding, air pressure molding, plug assist molding).
As an example of a preferred aspect of the present embodiment, the container is formed by subjecting a heated styrene-based resin composition sheet body to thermoforming, vacuum forming, air pressure forming, or plug-assist forming using the mold 1 . can be shaped.
When manufacturing a container, the diameter of the upper surface of the concave portion of the mold 1 (= the diameter of the opening (φ80 cm as an example in FIG. 1)) and the depth of the concave portion of the mold 1 (in FIG. As an example, the drawing ratio, which is a ratio of 40 cm), can be changed. In FIG. 1, as an example, a state in which a spacer 2 with a height of 80 cm is provided in a recess with a depth of 120 is shown. Also, the drawing ratio is represented by the following equation (2).
Aperture ratio = height / diameter of aperture Formula (2)

[Method for producing styrene resin composition]
The styrenic resin composition of the present embodiment can be produced by melt-kneading each component by an arbitrary method. For example, a method using a high-speed stirrer typified by a Henschel mixer, a batch type kneader typified by a Banbury mixer, a single-screw or twin-screw continuous kneader, a roll mixer, or the like, alone or in combination. The heating temperature during kneading is usually selected in the range of 180 to 250°C.

[Molding]
A molded article of the present invention is characterized by containing the above styrene-based resin composition.
The styrene-based resin composition of the present embodiment can be produced by injection molding, injection compression molding, extrusion molding, or blow molding using the above-described melt-kneading molding machine or pellets of the obtained styrene-based resin composition as raw materials. A molded product can be produced by a method, a press molding method, a vacuum molding method, a foam molding method, or the like.

Molded articles, preferably extruded articles, containing the styrene-based resin composition of the present embodiment include food containers (side dishes, lunch containers, microwave oven containers, rice bowls, cups, trays, etc.), sheets, food films and insulating films, It is a foamed product, and injection molded products (including injection compression) are used in office automation equipment such as copiers, faxes, personal computers, printers, information terminals, refrigerators, vacuum cleaners, microwave ovens, home appliances, electrical and electronic products. It is suitably used for equipment housings and various parts, interior and exterior parts of automobiles, construction materials, foamed heat insulating materials, and the like.

EXAMPLES The embodiments of the present invention will be described in more detail below based on Examples and Comparative Examples, but the present invention is not limited to these Examples.

<Measurement and evaluation method>
The physical properties of the resin compositions obtained in Examples and Comparative Examples were measured and evaluated according to the following methods.
(1) Contents of styrene monomer units, methacrylic acid monomer units, and methyl methacrylate monomer units in the styrene resin (a) Measured with a proton nuclear magnetic resonance ( ¹ H-NMR) spectrometer. The resin composition was quantified from the integral ratio of the spectrum.
・Sample preparation: 30 mg of resin pellets were dissolved in 0.75 mL of d ₆ -DMSO by heating at 60° C. for 4 to 6 hours.
・Measurement equipment: JNM ECA-500 manufactured by JEOL Ltd.
Measurement conditions: measurement temperature of 25° C., observation core of ¹ H, accumulation times of 64, repetition time of 11 seconds.

(Assignment of spectra)
Regarding the assignment of spectra measured in dimethylsulfoxide deuterated solvent, the peaks at 0.5 to 1.5 ppm are the peaks derived from the hydrogens of the α-methyl groups of methacrylic acid, methyl methacrylate, and six-membered cyclic anhydrides; The peak at 1.6 to 2.1 ppm is the peak derived from the hydrogen of the methylene group in the main chain of the polymer, the peak at 3.5 ppm is the peak derived from the hydrogen of the carboxylic acid ester (—COOCH ₃ ) of methyl methacrylate, and the peak at 12.4 ppm is The peak is derived from the hydrogen of the carboxylic acid of methacrylic acid. Also, the peak at 6.5 to 7.5 ppm is the peak derived from the hydrogen of the aromatic ring of styrene. In addition, since the resins of the present examples and comparative examples have a small content of six-membered cyclic acid anhydride, quantification is usually difficult by this measurement method.

(2) Weight Average Molecular Weight of Styrene Resin (a) The weight average molecular weight of the styrene resin (a) was measured under the following conditions and procedures.
- Sample preparation: About 0.05% by mass of resin was dissolved in tetrahydrofuran.
・Measurement conditions Equipment: TOSOH HLC-8220GPC
(Gel permeation chromatography)
Column: super HZM-H
Temperature: 40°C
Carrier: THF 0.35 mL/min
Detector: RI, UV: 254 nm
Calibration curve: Created using TOSOH standard PS.

(3) Melt flow rate (MFR)
The melt mass flow rate (g/10 minutes) of the styrene resin (a) was measured according to ISO 1133 (200°C, load 49N).

(4) Heat shrinkage rate Heat shrinkage rate (%) is measured by measuring the size in the length direction after leaving the test piece (a) prepared by the method described later in an oven under an atmosphere of 120 ° C. for 30 minutes. Then, the heat shrinkage rate was determined using the following formula (1).
Heat shrinkage =|(db-da)/da| formula (1)
(In the above formula (1), da represents the longitudinal length of the test piece before standing for 30 minutes in an atmosphere of 120 ° C. db is the length of the test piece after standing for 30 minutes in an atmosphere of 120 ° C. represents the length in the axial direction.)

(5) Extensibility A container having a draw ratio of 0.5 was vacuum-formed as shown in FIG. Non-defective product ◯ (ratio of bottom sidewall thickness/top sidewall thickness is 1 to 0.3), uneven thickness △ (bottom sidewall thickness/top sidewall thickness ratio is less than 0.3), hole It is written as Aki x.
The drawing ratio is represented by the following formula (2).
Drawing ratio = height of container / diameter of opening of container Equation (2)

(6) Oil resistance After heating the test piece (a) prepared by the method described below at 80 ° C. for 2 hours in a hot air dryer, Nisshin Salad Oil (manufactured by Nisshin Oillio Group Co., Ltd.) was tested at room temperature. 2 g was applied to the central portion of the piece (b), and the state after 6 hours was observed. A test piece with no change in appearance was rated ⊚ (excellent), a test piece with cracks on its surface was rated ◯ (good), and a test piece with fracture was rated x (bad).

(7) Measurement of Average Length An ultra-thin section with a thickness of 75 nm was prepared from the test piece (b) and photographed at a magnification of 50,000 using an electron microscope. Then, the photograph is captured in a scanner at a resolution of 200 dpi, and the minimum length and maximum length of 100 cellulose (b) are measured using particle analysis software of an image analyzer IP-1000 (manufactured by Asahi Kasei Corporation). , the arithmetic mean of each was defined as the average short axis length d ₁ and the average length of the long axis d ₂ .

(8) Measurement of hemicellulose amount Quantitative analysis of hemicellulose in cellulose (b) is as follows.
The dispersion medium is removed from the dispersion of cellulose (b) or the redispersion of cellulose (b) obtained by dissolving and removing the resin from the styrene resin composition, and the cellulose residue is recovered and dried at 105°C. The mass of the dried sample obtained by this was measured by the following method.
A pulverized sample obtained by pulverizing dried cellulose residue was extracted with alcohol (ethanol)/benzene mixed solvent) for 6 hours using a Soxhlet extractor. After that, extraction with alcohol (ethanol)/benzene mixed solvent) was performed for an additional 4 hours to obtain a defatted sample. 150 mL of distilled water, 1.0 g of sodium chlorite, and 0.2 mL of acetic acid are added to 2.5 g of the defatted sample, and heat treatment is performed at 70 to 80 ° C. for 1 hour. The operation of adding .2 mL and heating at 70 to 80° C. for 1 hour was repeated 3 to 4 times until the sample became white and decolored. The resulting sample was filtered, washed with water and acetone, and dried at 105° C. to obtain a holocellulose fraction (total amount of α-cellulose and hemicellulose). The mass of this holocellulose fraction was measured.
Subsequently, 25 mL of a 17.5% by mass sodium hydroxide aqueous solution was added to 1.0 g of the holocellulose fraction, and after 3 minutes, the mixture was lightly crushed with a glass rod until it became swollen. After that, leave the mixture at 20°C, and 30 minutes after adding the aqueous sodium hydroxide solution, add 25 mL of distilled water, stir for exactly 1 minute, leave at 20°C for 5 minutes, and filter through a glass filter. Wash until the liquid becomes neutral. Further, 40 mL of 10% by mass acetic acid was suction-filtered, then 1 L of boiling water was suction-filtered, and the washed sample was dried at 105° C. until the mass became constant to obtain an α-cellulose fraction. The mass of this α-cellulose fraction was measured.
From the masses of the holocellulose fraction and the α-cellulose fraction determined as described above, the hemicellulose content was determined by the following equation.
Holocellulose (%) = holocellulose fraction (g) / sample (anhydrous basis) (g) x 100
α-cellulose (%) = α-cellulose fraction (g) / sample (anhydrous basis) (g) × 100
Hemicellulose (%) = Holocellulose (%) - (α-cellulose (%))

(9) Quantification of Lignin Amount Quantitative analysis of lignin in cellulose (b) was based on the TGA method described in Journal of Waste Recycling Society Vol.22, N0.5, P293, 2011.
A DTG-60 model manufactured by Shimadzu Corporation was used as a thermogravimetric analyzer, and the temperature was raised from room temperature to 900°C at a temperature elevation rate of 10°C/min in an air atmosphere. The sample to be analyzed was dried at 70° C. for 2 hours, weighed accurately in an amount of 3 to 5 mg, and the change in weight due to thermal decomposition was measured. A disk-shaped platinum dish with an inner diameter of 5 mm and a height of 2 mm was used as a sample container, and all experiments were carried out under constant conditions.

Materials used in Examples and Comparative Examples are as follows.
[Styrene resin (a)]
<GPPS(1)>
- Polystyrene (GPPS, PS Japan Co., Ltd., HF77) having an MFR of 7.8 and a refractive index of 1.598 was used.
<GPPS(2)>
- Polystyrene (GPPS, manufactured by PS Japan Co., Ltd., HF77 and G9401 blended at 1:1) with MFR 4.8 was used.
<HIPS (1)>
- Polystyrene (HIPS, PS Japan Co., Ltd., H9152) with MFR 5.5 was used.
<HIPS (2)>
- Polystyrene of MFR 4.5 (HIPS, manufactured by PS Japan Co., Ltd., a 1:1 blend of H9152 and 475D) was used.
<Copolymer (1)>
Polymerization of 70.0 parts by mass of styrene (ST), 15.0 parts by mass of butyl methacrylate (BA), 15.0 parts by mass of ethylbenzene, and 0.02 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane The raw material composition solution is transferred at a rate of 1.1 liters/hour to a fully mixed reactor having a capacity of 4 liters, then to a polymerization apparatus consisting of a laminar flow reactor having a capacity of 2 liters, and then to unreacted monomers. , to a devolatilization device connected to a single-screw extruder for removing volatile matter such as a polymerization solvent, to prepare Copolymer-1, which is a styrene-based copolymer resin.
The polymerization reaction conditions in the polymerization process were a polymerization temperature of 122° C. in the complete mixing reactor and a polymerization temperature of 120 to 142° C. in the laminar flow reactor. The devolatilized unreacted gas was condensed in a condenser through which a -5° C. refrigerant was passed, and recovered as an unreacted liquid.
The polymer content in the final polymerization liquid was measured by the formula [(sample mass after drying / sample mass before drying) x 100%] after drying the polymerization liquid for 30 minutes at 215 ° C. under a reduced pressure of 2.5 kPa. , 65.6 mass %, and the MFR was 5.1.
<Copolymer (2)>
It was produced in the same manner as [Copolymerization-1] except that 55.0 parts by mass of styrene (ST) and 30.0 parts by mass of methyl methacrylate (BA) were used. MFR was 4.2.

[Cellulose (b)]
・Cellulose fiber (manufactured by Celite, SW-10, d ₁ : 20 μm, d ₂ : 700 μm, hemicellulose content 11% by mass, lignin content 0.5%)
・CNF: cellulose nanofiber (manufactured by Chuetsu Pulp Co., Ltd., CNF-10, d ₁ : 35 nm, d ₂ : about 1 μm, hemicellulose content 15% by mass, lignin content 0.2%)
・Cotton powder (manufactured by DTI Co., Ltd., 100% cotton pulverized product, spherical body, d ₁ : 25 μm, d ₂ : 35 μm, hemicellulose content 0.5% mass or less, lignin content 0.1%)
・ Wood flour (manufactured by Naka Wood Co., Ltd., raw material: cedar, d ₁ : 120 μm, d ₂ : 180 μm, lignin content 23%, hemicellulose content 18% by mass)

[Rubber-like polymer (c) modified with unsaturated carboxylic acid compound]
・Maleic anhydride-modified SEBS (manufactured by Asahi Kasei Corporation, M1913, MFR5, S/EB ratio 30/70)
· Maleic anhydride-modified ethylene-α-olefin copolymer (manufactured by Big Chemie, Scona TSPOE 1002 GBLL, MFR3)

[Comparative compound]
・SEBS (manufactured by Asahi Kasei Corporation, H1041, MFR5, S/EB ratio 30/70)
・ SMA copolymer (XIBOND250 manufactured by POLYSCOPE)

[Additive]
(Phenolic antioxidant)
· 3-(3,5-di-tert-butyl-4-hydroxyphenyl) stearyl propionate (manufactured by BASF, Irganox 1076)
(Phosphorus antioxidant)
・ Tris (2,4-di-tert-butylphenyl) phosphite (manufactured by BASF, Irgafos168)

[Examples 1 to 11]
Each component is added in the composition ratio shown in Table 1, and 0.2 parts by mass of Irganox 1076 and Irgafos 168 are added as antioxidants to a total of 100 parts by mass of components (a) to (c). Premixed. The resulting preliminary mixture is mixed together, melt-extruded at 180 ° C. to 220 ° C. using a twin-screw extruder (Toshiba Machine Co., Ltd., TEM-26SS), and a pellet-shaped styrene resin composition as a kneaded product. got stuff At this time, the screw rotation speed was 150 rpm, and the discharge rate was 10 kg/hr. The pelletized styrene resin composition thus obtained was molded using an injection molding machine manufactured by Japan Steel Works, Ltd. equipped with an ISO standard test piece type (a) mold, and a cylinder temperature of 220 ° C. and a mold temperature of A test piece (a) was prepared by molding at 50° C., injection pressure (gauge pressure 40-60 MPa), injection speed (panel set value) 50%, injection time/cooling time=5 sec/20 sec. Using the obtained test piece (a), heat shrinkage and oil resistance were evaluated.
A non-foamed extruded sheet was produced using the obtained pellet-shaped styrene-based resin composition. For the non-foamed extruded sheet, a 25 mm diameter single screw sheet extruder manufactured by Soken Co., Ltd. was used to set the temperature of the resin melting zone to 180 to 200° C., and a sheet having a thickness of about 0.8 mm was produced. Using the obtained sheet, a container shown in FIG. 1 was produced. As for the container, using a sheet container molding machine manufactured by Soken Co., Ltd., a heating zone was set at 200° C., and a container with a drawing ratio of 50% was vacuum-formed to evaluate the ductility.

[Comparative Examples 1 to 9]
Comparative Examples 1 to 11 were carried out in the same manner as in Example 1, except that the compositions were changed as shown in Table 2. Table 2 shows the results of measurement and evaluation of each physical property.

As shown in Table 1, Examples 1 to 11 are excellent in heat resistance, spreadability, and oil resistance due to low heat shrinkage. In particular, when the amount of lignin is 20% by mass or less, or the amount of hemicellulose is 1% by mass or more, spreadability and oil resistance are enhanced.
As in Comparative Examples 1 and 2 shown in Table 1, if the amount of cellulose deviates from the predetermined amount, oil resistance and spreadability are lowered. In addition, as in Comparative Examples 3 and 4, when the rubber-like polymer modified with an unsaturated carboxylic acid or its anhydride, or a derivative thereof is removed from the predetermined amount, the extensibility is lowered and the heat resistance is lowered. do. Furthermore, as in Comparative Examples 5 to 7, rubber-like elastomers not modified with unsaturated carboxylic acids or their anhydrides, maleic anhydride-modified styrenic resins, and combinations thereof are inferior in spreadability and oil resistance. Furthermore, as in Comparative Examples 8 to 10, if the MFR of the styrene resin is lower than 5, ductility cannot be obtained.

Molded articles containing the styrene-based resin composition of the present invention can be suitably used for packaging materials, building materials, electronic/electric parts, automobiles, and the like.

Claims (6)

25 to 89% by mass of a styrene resin (a) having an MFR of 5 or more,
10 to 55% by mass of cellulose (b),
A styrenic resin composition comprising 1 to 20% by mass of a rubber-like polymer (c) modified with an unsaturated carboxylic acid compound. 2. The styrenic resin composition according to claim 1, wherein the rubbery polymer (c) is a maleic anhydride-modified styrenic rubbery polymer. The styrene-based resin composition according to any one of claims 1 and 2, wherein the cellulose (b) is cellulose containing 20% by mass or less of lignin. The styrenic resin composition according to any one of claims 1 to 3, wherein the cellulose (b) is cellulose containing 1% by mass or more of hemicellulose. A molded article comprising the styrenic resin composition according to any one of claims 1 to 4. A sheet or film comprising the styrenic resin composition according to any one of claims 1 to 4.

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