TW202340360A - Styrene-based resin composition, molded article using the same, carrier tape for transporting electronic parts - Google Patents

Abstract

An object of the present disclosure is to provide a styrene-based resin composition that maintains a certain level of transparency while suppressing and preventing the thinning during molding and has excellent deep drawing moldability during molding, a molded article using the composition, and a carrier tape for transporting electronic parts. The styrene-based resin composition contains: rubber-like polymer particles containing a rubber-like polymer, and a styrene-based polymer constituting a polymer matrix phase; the styrene-based polymer contains: a styrene-based monomer unit (a1), a (meth)acrylate monomer unit (a2) in an amount of 7 to 50 % by mass, and a (meth)acrylate monomer unit (a3) having a larger molecular weight than the (meth)acrylate monomer unit (a2) in an amount of 0.001 to 20% by mass; the polymer matrix phase has a refractive index of 1.538 to 1.575; the absolute value of the difference between the refractive indexes of the polymer matrix phase and the rubber-like polymer particles is in the range of 0 to 0.015; the number average molecular weight (Mn) of the styrene-based polymer is 40,000 to 120,000 and the weight average molecular weight (Mw) of the styrene-based polymer is 100,000 to 300,000; the MFR of the styrene-based resin composition is within the range of 1.5g/10 mins to 5.0g/10 mins.

Description

Styrenic resin composition, molded article using the composition, and carrier tape for transporting electronic parts

The present invention relates to a styrenic resin composition, a molded article using the same, and a carrier tape for transporting electronic parts.

Styrenic resins are used in various industrial fields as foams, sheets, shells, etc. due to their characteristics such as light weight and easy moldability. However, the impact strength of styrenic resin is low, and its uses are limited. Particularly when polystyrene-based resins are used as industrial materials, it is important to improve impact resistance without reducing rigidity such as elastic modulus. Therefore, impact-resistant polystyrene (HIPS), which is a polystyrene-based resin with improved impact resistance, has a structure in which rubber-like particles are dispersed in a polystyrene resin matrix. Therefore, impact resistance and dimensional stability are stable. It has excellent properties, formability and processability, and is used in a variety of technical fields.

However, with the diversification of technical fields in recent years, higher levels of impact strength, formability, etc. are required than before. In particular, in conjunction with the recent development of forming processing technology that can be formed into complex shapes, food containers (for example, those that can be heated in a microwave oven) Styrenic resin compositions used in container materials or housing materials such as lunch boxes) or electronic parts packaging materials (for example, carrier tapes for storing electronic parts such as ICs and LSIs) are also required to have excellent transparency, formability, High toughness and mechanical strength. Therefore, various technologies using rubber-modified polystyrene-based resins (also called HIPS) that are relatively excellent in impact resistance have been proposed. Among them, Patent Document 1 is cited as an example of a technology that further improves the impact resistance. Generally, in order to improve impact resistance, it is known to increase the content of rubber-like particles in a rubber-modified polystyrene-based resin. However, when the content of the rubber-like polymer is increased, the problem of decreased rigidity and fluidity occurs. Therefore, a technology disclosed in Patent Document 1 aims to provide a rubber-modified vinyl aromatic composition. By introducing a vinyl aromatic polymer component with a specific branched chain structure into the components constituting the continuous phase of the polystyrene resin matrix, the fluidity is further improved without compromising the impact strength.

Furthermore, Patent Document 2 discloses a technology in which a laminate sheet containing a vinyl aromatic hydrocarbon-conjugated diene block copolymer, A surface layer containing a rubber-modified (meth)acrylate-vinyl aromatic hydrocarbon copolymer is provided on a base layer of a vinyl aromatic hydrocarbon polymer and/or a rubber-modified vinyl aromatic hydrocarbon polymer. of.

[Prior technical literature]

[Patent Document]

Patent Document 1: Japanese Patent Application Laid-Open No. 8-169920

Patent Document 2: International Publication No. 2019/146630

However, although the technology of Patent Document 1 is a rubber-modified vinyl aromatic polymer composition showing high fluidity, it does not examine the control of the particle size and rubber content of the rubber-like polymer particles contained in the system. Therefore, not only strength characteristics such as impact resistance are insufficient, but also the balance with transparency and formability is insufficient. In particular, transparency and deep drawing formability have a lot of room for improvement.

However, as described in the above-mentioned Patent Document 2, rubber-modified polystyrene-based resins represented by rubber-modified (meth)acrylate-vinyl aromatic hydrocarbon copolymer and the like are used as materials for containers such as carrier tapes. In the case of hot forming into a container shape, when forming a recessed portion with a relatively large deep drawing ratio, the thickness of the bottom portion or side portion of the recessed portion will be significantly thinned, making it difficult to obtain a recessed portion with sufficient strength. Therefore, in the technology of Patent Document 2, deep drawing formability is improved by laminating different types of materials, but it cannot provide a composition using a single material that has sufficient transparency and deep drawing formability for practical use.

Therefore, an object of the present application is to provide a styrene-based resin composition that maintains a certain level of transparency, suppresses and prevents thinning during molding, and has excellent deep drawing formability during molding, and uses the same. Carrier tapes for transporting molded objects, containers and electronic parts.

The inventors of the present invention conducted in-depth research in order to solve the above-mentioned problems, and as a result, successfully realized a styrene-based resin composition, a molded article (including a sheet) using the resin composition, and further secondary molding of the molded article. Containers or carrier tapes for transporting electronic parts, wherein, The present invention has been completed by the styrene-based resin composition containing a polymer matrix phase containing a predetermined styrene-based polymer and rubber-like polymer particles containing a rubber-like polymer.

[1] The content of this application is a styrenic resin composition, which contains:

rubbery polymer particles containing a rubbery polymer, and

Styrenic polymers constituting the polymer matrix phase; wherein

The aforementioned styrene-based polymer has: a styrene-based monomer unit (a1) and a (meth)acrylate monomer unit (a2) of 7 to 50% by mass. (meth)acrylate monomer unit (a3) with large molecular weight: 0.001 to 20% by mass,

The refractive index of the aforementioned polymer matrix phase is 1.538 to 1.575, and the absolute value of the difference in refractive index between the aforementioned polymer matrix phase and the aforementioned rubber-like polymer particles is in the range of 0 to 0.015,

The number average molecular weight (Mn) of the aforementioned styrenic polymer is 40,000 to 120,000, and the weight average molecular weight (Mw) of the aforementioned styrenic polymer is 100,000 to 300,000,

The MFR of the styrenic resin composition is in the range of 1.5 g/10 minutes to 5.0 g/10 minutes.

[2] The styrenic resin composition according to [1], wherein the proportion of high molecular weight components of 1 million or more in the molecular weight of the polymer matrix phase is less than 1%.

[3] The styrenic resin composition according to [1] or [2], wherein among all the rubber-like polymer particles contained in the styrenic resin composition, the proportion of the rubber-like polymer particles is More than 21% by volume has a Salami structure.

[4] The styrenic resin composition according to any one of [1] to [3], wherein the (meth)acrylate monomer unit (a2) is a methyl (meth)acrylate monomer unit, and the aforementioned (meth)acrylate monomer unit (a3) is butyl (meth)acrylate.

[5] The styrene-based resin composition according to any one of [1] to [4], wherein the styrene-based resin composition according to any one of [1] to [4] is used as a molded The haze value of the 0.3mm thick test piece of the raw material is 30% or less.

[6] The styrenic resin composition according to any one of [1] to [5], wherein the conjugated diene constituting the rubbery polymer is less than the entire styrenic resin composition. The content of monomer units is 3 to 13% by mass.

[7] The styrenic resin composition according to any one of [1] to [6], wherein the rubber-like polymer particles have an average particle diameter of 0.4 μm or more and 0.95 μm or less.

[8] The styrenic resin composition according to any one of [1] to [7], which contains 0.03 to 0.7 mass % of the higher fatty acid compound relative to the entire styrenic resin composition.

[9] The styrenic resin composition according to any one of [1] to [8], further containing 0.001 to 0.5 mass % of an antioxidant based on the entire styrenic resin composition.

[10] A molded article formed from the styrene-based resin composition described in any one of [1] to [9].

[11] A carrier tape for transporting electronic components, which is composed of a base material having a plurality of recessed portions for accommodating electronic components, and an edge portion capable of being bonded to a cover that seals the recessed portions, wherein:

The base material contains the styrenic resin composition described in any one of [1] to [9].

According to the present invention, it is possible to provide a styrene-based resin composition that maintains a certain level of transparency, suppresses and prevents thinning during molding, and has excellent deep drawing formability during molding.

According to the present invention, it is possible to provide a styrene-based resin composition for containers, a molded article, a container, and a carrier tape for transporting electronic parts while maintaining a certain level of transparency, suppressing and preventing thinning, and having excellent deep drawing formability. .

1:Food container

2: Food container body

3: Cover part

4: concave part

5: slot

6:Opening part

7: Bottom face

8: Edge part

9: Mold

10: Sheet body

11: concave part

12: Spacer

21: Carrier tape body

22: concave part

23: Edge

24:Through hole

25:Electronic parts

26:Sealing part

27: cover tape

Fig. 1 is a perspective view showing an example of a food container obtained from the styrenic resin composition of this embodiment.

Fig. 2 is a diagram showing a form of a food container produced from a sheet obtained using the styrene-based resin composition of the present embodiment.

3 is a diagram showing a carrier tape for transporting electronic components as an example of the packaging material for electronic components according to the present embodiment, and a diagram showing storage using the carrier tape for transporting electronic components obtained from the styrene-based resin composition of the present embodiment. A three-dimensional view of the form of electronic components.

FIG. 4 is a perspective view showing a state in which electronic components are stored using the packaging material for transporting electronic components according to this embodiment.

FIG. 5 is a diagram showing the proportions of high molecular weight components of 700,000 or more, 800,000 or more, and 1,000,000 or more among the molecular weights of the polymer matrix phase of this embodiment.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail. However, the present invention is not limited to the following description and can be implemented with various modifications within the scope of the gist.

[Styrenic resin composition]

The styrene-based resin composition of this embodiment contains a styrene-based polymer constituting a polymer matrix phase, and rubber-like polymer particles containing a rubber-like polymer. Furthermore, the aforementioned styrene-based polymer has: a styrene-based monomer unit (a1) and a (meth)acrylate monomer unit (a2) of 7 to 50% by mass, which are larger than the aforementioned (meth)acrylate monomer unit (a2). a2) 0.001 to 20 mass % of (meth)acrylate monomer unit (a3) with a large molecular weight. Furthermore, the refractive index of the polymer matrix phase is 1.538 to 1.575, and the absolute value of the difference in refractive index between the polymer matrix phase and the rubber-like polymer particles is in the range of 0 to 0.015. The number average molecular weight (Mn) of the styrenic polymer is 40,000 to 120,000, and the weight average molecular weight (Mw) of the styrenic polymer is 100,000 to 300,000. In addition, the MFR of the styrenic resin composition is in the range of 1.5 g/10 minutes to 5.0 g/10 minutes. In addition, the styrene-based resin composition of this embodiment may be a styrene-based resin composition for containers.

A styrenic resin having a polymer matrix phase composed of a styrenic polymer having a specific composition, molecular weight, and refractive index, and rubber-like polymer particles having a specific refractive index difference with respect to the polymer matrix phase. The composition can suppress and prevent thinning during molding while maintaining a certain level of transparency, and exhibit excellent deep drawing formability during molding.

It should be noted that the above-mentioned certain level of transparency means that the haze value of the 0.3mm thick sheet is below 30%.

The styrene-based resin composition of this embodiment contains rubber-like polymer particles containing a rubber-like polymer and a polymer matrix phase containing a styrenic-based polymer. The rubber-like polymer particles can be dispersed in the polymer matrix phase (so-called continuous phase). Therefore, the polymer matrix is compared to the sea phase, and the rubber-like polymer particles are compared to the island phase, which can also be called an island structure.

Hereinafter, each component constituting the styrenic resin composition according to the present invention will be described below.

(polymer matrix phase)

The polymer matrix phase in this embodiment refers to the resin component other than the rubber-like polymer particles containing the rubber-like polymer in the so-called styrenic resin composition. Strictly speaking, regarding one or two or more ingredients selected from the group consisting of higher fatty acid compounds, antioxidants, plasticizers, and optionally added ingredients, it or a part of them may be allocated to in either the polymer matrix phase or the rubbery polymer particles. Therefore, it is difficult to clearly distinguish the components contained in the polymer matrix phase. However, the polymer matrix phase in this embodiment may contain a styrene-based polymer as a main component and a compound selected from the group consisting of higher fatty acid compounds, antioxidants, One or more components from the group consisting of plasticizers and optional additional components.

The polymer matrix phase in this embodiment contains a styrenic polymer as a main component, and the styrenic polymer has a styrene monomer unit (a1), a (meth)acrylate monomer unit (a2) and ( Meth)acrylate monomer unit (a3). In this specification, "y is the main component constituting x" or "x contains y as the main component" means that y accounts for 60 mass% or more of the total amount of x (100 mass).

Furthermore, as a preferred aspect of this embodiment, the polymer matrix phase may be substantially composed only of a styrenic polymer except for inevitable impurities. Moreover, it is preferable that the styrene-based polymer of this embodiment exists inside and outside the rubber-like polymer particles. exterior styrene The styrenic polymer or the phase containing the styrenic polymer is called the polymer matrix phase. When a styrene-based polymer exists inside the rubber-like polymer particles, a salami-type structure or a core-shell type structure described below is formed. Rubber-like polymer particles having such a structure can be obtained by, for example, adding a styrene-based monomer (a1), a (meth)acrylate monomer (a2), and (meth)acrylic acid in the presence of a rubber-like polymer (particle). Obtained by polymerizing ester monomer (a3).

The upper limit of the content of the polymer matrix phase in the styrenic resin composition of this embodiment is preferably 80 mass% or less, 74 mass% or less, or 70 mass% with respect to 100 mass% of the total amount of the styrenic resin composition. Below, below 63 mass%, below 60 mass%, below 56 mass%, below 50 mass%, below 44 mass%, below 40 mass%, below 35 mass%, below 30 mass%, below 24 mass%, 20 mass% or less, 18 mass % or less, 12 mass % or less, 10 mass % or less, 8 mass % or less, 7 mass % or less, 5 mass % or less, 3 mass % or less, 2.7 mass % or less or 2.3 mass % or less. On the other hand, the lower limit of the content of the polymer matrix phase in the styrene-based resin composition is preferably 0.1 mass% or more, 0.2 mass% or more, and 0.3 mass% with respect to 100 mass% of the total amount of the styrene-based resin composition. % or more, 0.4 mass% or more, 0.5 mass% or more, 0.7 mass% or more, 1 mass% or more, 1.2 mass% or more, 1.6 mass% or more, 9 mass% or more, 12 mass% or more, 19 mass% or more, 22 mass% % or more, 25 mass% or more, 31 mass% or more, 40 mass% or more or 42 mass% or more. These upper and lower limits can each be combined arbitrarily.

The refractive index of the polymer matrix phase of this embodiment is from 1.538 to 1.575, preferably from 1.539 to 1.573, more preferably from 1.540 to 1.571, and even more preferably from 1.541 to 1.570. Furthermore, in other embodiments, the refractive index of the polymeric matrix phase is preferably in the range of 1.541 to 1.575.

When transparency is important, the refractive index of the polymer matrix phase is preferably 1.538 to 1.550, more preferably 1.541 to 1.548. On the other hand, when attaching importance to deep drawing formability during molding and obtaining a certain degree of transparency, the refractive index of the polymer matrix phase is preferably 1.550 to 1.573, more preferably 1.550 to 1.571.

When the refractive index of the polymer matrix phase is in the range of 1.538 to 1.575, it is good from the viewpoint of material selection since it can be selected from commercially available rubber-like polymers. In order to control the refractive index of the polymer matrix phase within the above range, the styrenic monomer (a1), (meth)acrylate monomer (a2) and (meth)acrylate monomer (a3) need to be The conditions under which the composition is adjusted.

In this embodiment, the absolute value of the difference in refractive index between the polymer matrix phase and the rubber-like polymer particles is in the range of 0 to 0.015. The formability of the styrenic resin composition of the present embodiment, specifically, when paying attention to the balance between deep drawing formability and thickness variation, is the absolute difference in the refractive index between the polymer matrix phase and the rubber-like polymer particles. The value is preferably in the range of 0.005 to 0.01, more preferably in the range of 0.006 to 0.01, and still more preferably in the range of 0.007 to 0.01. When the absolute value of the difference in refractive index between the polymer matrix phase and the rubber-like polymer particles is within the above range, moderate visibility and excellent deep drawability can be ensured.

On the other hand, when emphasis is placed on the transparency of the styrenic resin composition of the present embodiment, it is preferably in the range of 0 to 0.005, more preferably in the range of 0 to 0.004, and still more preferably 0 to the range of 0.003.

In order to set the absolute value of the difference in refractive index between the polymer matrix phase and the rubber-like polymer particles within the above range, it is necessary to adjust the refractive index of the polymer matrix phase according to the refractive index of the rubber component used in the rubber-like polymer. conditions.

The method for measuring the refractive index in this specification uses the method described in the section of Examples described later.

In this embodiment, the weight average molecular weight (Mw) of the polymer matrix phase is preferably 100,000 to 300,000, more preferably 150,000 to 300,000, still more preferably 150,000 to 270,000, and more preferably 150,000 to 270,000. Better is 150,000 to 240,000. When the weight average molecular weight is less than 100,000, the impact strength of the styrenic resin composition may decrease. When the weight average molecular weight exceeds 300,000, the fluidity of the styrenic resin composition decreases, which may hinder productivity.

When transparency is important, the weight average molecular weight (Mw) of the polymer matrix phase is preferably 100,000 to 240,000, more preferably 100,000 to 200,000. On the other hand, when paying attention to the balance between deep drawing formability and thickness variation, the weight average molecular weight (Mw) of the polymer matrix phase is preferably 150,000 to 300,000, more preferably 150,000 to 270,000.

In addition, the measurement method of the weight average molecular weight in this invention is performed by the method described in the paragraph of "Examples".

In this embodiment, the number average molecular weight (Mn) of the polymer matrix phase is preferably 40,000 to 120,000, more preferably 45,000 to 120,000, still more preferably 50,000 to 115,000, and still more preferably The best range is 50,000 to 110,000. When the number average molecular weight is less than 40,000, the impact strength of the styrenic resin composition may decrease. When the number average molecular weight exceeds 120,000, the fluidity of the styrenic resin composition decreases, which may hinder productivity. In addition, the measurement method of the number average molecular weight in this invention is performed by the method described in the paragraph of "Examples".

Hereinafter, the styrenic polymer which is a constituent component of the polymer matrix phase and the optional component higher fatty acid compound will be described.

"Styrenic polymer"

The styrene-based resin composition of this embodiment contains a styrene-based polymer having: styrene-based monomer unit (a1), (meth)acrylate monomer unit (a2) 7 to 50 0.001 to 20 mass% of the (meth)acrylate monomer unit (a3) having a larger molecular weight than the aforementioned (meth)acrylate monomer unit (a2). By containing the above-mentioned styrene-based polymer in the styrene-based resin composition, the refractive index of the entire polymer matrix phase of the styrenic-based resin composition can be controlled to a predetermined value. In particular, styrenic polymers can maintain a certain level of transparency by having a specific weight average molecular weight (Mw), number average molecular weight (Mn), and a specific range of melt mass flow rate (MFR). It imparts fluidity, suppresses and prevents thinning during molding, and exhibits excellent deep drawing formability during molding.

The styrene-based polymer of this embodiment contains a styrene-based monomer unit (a1), a (meth)acrylic acid ester monomer unit (a2), and a (meth)acrylic acid ester monomer unit (a3). In other words, the polymer matrix phase is composed mainly of a styrene-based polymer having a styrene-based monomer unit (a1) and a (meth)acrylic acid ester monomer unit (a2).

Furthermore, the rubber-like polymer particles are preferably dispersed in the polymer matrix phase. Furthermore, the rubber-like polymer particles may have a structure in which the styrene-based polymer is encapsulated.

Therefore, in other words, the styrene-based resin composition of this embodiment contains: a styrene-based monomer unit (a1), a (meth)acrylate monomer unit (a2), and a (meth)acrylate monomer unit. (a3) A polymer matrix phase composed of the styrene-based polymer and rubber-like polymer particles. Furthermore, the polymer matrix phase contains a higher fatty acid compound. Furthermore, the rubber-like polymer particles may contain the styrenic polymer.

In the styrenic resin composition of this embodiment, the upper limit of the content of the styrenic polymer is preferably 99.97 mass% or less, more preferably 99 mass% or less based on 100 mass% of the total amount of the styrenic resin composition. , 97 mass% or less, 96 mass% or less, 93 mass% or less. On the other hand, the lower limit of the content of the styrenic polymer is preferably 60 mass% or more, 65 mass% or more, 70 mass% or more, or 77 mass% or more, based on 100 mass% of the total amount of the styrenic resin composition. 78 mass% or more, 80 mass% or more, 83 mass% or more, 87 mass% or more, 90 mass% or more, 97 mass% or more. The upper limit and lower limit of the content of the aforementioned styrene-based polymer can be combined arbitrarily.

In the styrenic resin composition of this embodiment, the content of the styrenic polymer is preferably 60 mass% or more and 99.99 mass% or less, based on 100 mass% of the total amount of the styrenic resin composition, and more preferably 70 mass% or more and 99.98 mass% or less. By setting the content to 70% by mass or more, impact resistance can be further improved. In addition, by setting the content to 99.99% by mass or less, the rigidity can be further improved.

<Styrene-based monomer unit (a1)>

In this embodiment, the styrene-based monomer (a1) that can constitute the polymer matrix phase or the styrene-based polymer is not particularly limited, and examples thereof include styrene, α-methylstyrene, and paramethylstyrene. styrene, ethylstyrene, propylstyrene, butylstyrene, chlorostyrene, bromostyrene, etc. Especially from an industrial viewpoint, styrene is preferred. As the styrene-based monomer, these can be used alone or in mixture.

In addition, the "styrene-based monomer unit (a1)" in this specification refers to the repeating unit cell derived from the styrene-based monomer (a1), and more specifically, refers to the styrene-based monomer (a1) ) borrow Due to the polymerization reaction or cross-linking reaction, the unsaturated double bonds in the monomer (a1) become the structural unit cell of single bonds. It should be noted that the meanings of other "monomer units" are also the same as above.

In a preferred embodiment of the styrenic polymer of the present embodiment, from the viewpoint of ensuring the transparency of the entire styrenic resin composition, the styrene monomer unit (a1 ) content is determined from the viewpoint that the absolute value of the difference in refractive index between the polymer matrix phase and the rubber-like polymer particles falls within a predetermined range. Therefore, the content of the styrene-based monomer unit (a1) is set according to the type of rubber-like polymer particles (average particle diameter, composition, etc.).

In this embodiment, the upper limit of the content of the styrene-based monomer unit (a1) in the entire styrenic polymer is 90 mass% or less, 80 mass% or less, or 70 mass% or less with respect to the entire styrenic polymer. , 68 mass% or less, 67 mass% or less, 66 mass% or less, 65 mass% or less, 64 mass% or less, 63 mass% or less, 62 mass% or less, 61 mass% or less, 60 mass% or less, 59 mass% or less , 58 mass% or less, 57 mass% or less, 43 mass% or less, 38 mass% or less, 32 mass% or less, 28 mass% or less, and 23 mass% or less in this order. On the other hand, the lower limit of the content of the styrene-based monomer unit (a1) is 20 mass% or more, 25 mass% or more, 30 mass% or more, 35 mass% or more, or 40 mass% or more with respect to the entire styrene-based polymer. , 43% by mass or more, 44% by mass or more, 45% by mass or more, 46% by mass or more, 47% by mass or more, 48% by mass or more, 49% by mass or more, and 50% by mass or more, in this order. The above upper and lower limits may be combined appropriately.

In this embodiment, the styrene-based monomer unit (a1), (meth)acrylate monomer unit (a2), (meth)acrylate monomer unit (a3) and others in the styrene-based polymer The content of the monomer unit can be determined from the integral ratio of the spectrum of the styrenic polymer when measured with a nuclear magnetic resonance measuring device ( ¹ H-NMR).

<(Meth)acrylate monomer unit (a2)>

In this embodiment, the (meth)acrylate monomer unit (a2) preferably has an alkyl chain having 1 to 3 carbon atoms (R ² in the following general formula (1)) as an ester substituent. (meth)acrylate monomer unit (a2). At this time, the alkyl chain having 1 to 3 carbon atoms includes linear, branched or cyclic alkyl groups. Furthermore, the preferred alkyl chain having 1 to 3 carbon atoms is preferably a linear or branched alkyl group, and examples thereof include methyl, ethyl, propyl, and isopropyl.

As the (meth)acrylate monomer unit (a2) in this embodiment, it is preferably represented by the following general formula (1), for example:

(In the above general formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ² represents an ester substituent, specifically an alkyl group having 1 to 3 carbon atoms.)

Furthermore, the (meth)acrylate monomer unit (a2) has a smaller molecular weight than the (meth)acrylate monomer unit (a3). More specifically, the (meth)acrylate monomer unit (a2) is preferred. ) has a smaller number of carbon atoms than the ester substituent of the (meth)acrylate monomer unit (a3).

In this embodiment, specific examples of the (meth)acrylate monomer (a2) include: (methyl)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, Isopropyl (meth)acrylate, etc. Among these, the (meth)acrylate monomer is preferably methyl (meth)acrylate from an industrial viewpoint.

In this embodiment, the content of the (meth)acrylic acid ester monomer unit (a2) in the entire styrene-based polymer is preferably adjusted so that the refractive index of the styrene-based polymer becomes equal to that of the rubber-like polymer particles. The absolute value of the difference in refractive index is within a predetermined range (for example, 0 to 0.015).

In this embodiment, the content of the (meth)acrylic acid ester monomer unit (a2) in the entire styrene-based polymer is preferably adjusted so that the refractive index of the styrene-based polymer becomes equal to that of the rubber-like polymer particles. The absolute value of the difference in refractive index is within a predetermined range (for example, 0 to 0.01).

The upper limit of the content of the (meth)acrylate monomer unit (a2) in this embodiment is 90 mass% or less, 80 mass% or less, 70 mass% or less, 68 mass% or less, 67 mass% or less with respect to the entire styrenic polymer. Mass% or less, 66 mass% or less, 65 mass% or less, 64 mass% or less, 63 mass% or less, 62 mass% or less, 61 mass% or less, 60 mass% or less, 59 mass% or less, 58 mass% or less, 57 The order of mass % or less, 43 mass % or less, 38 mass % or less, 32 mass % or less, 28 mass % or less, and 23 mass % or less is preferred. On the other hand, the lower limit of the content of the (meth)acrylate monomer unit (a2) is 6.5% by mass or more, 6.9% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more with respect to the entire styrene-based polymer. The order of mass% or more, 42 mass% or more, 43 mass% or more, 44 mass% or more, 45 mass% or more, 46 mass% or more, 47 mass% or more, 48 mass% or more, 49 mass% or more, 50 mass% or more For better. The above upper and lower limits may be combined appropriately.

Furthermore, the content range of the (meth)acrylic acid ester monomer unit (a2) is preferably 10 to 90 mass %, more preferably 20 to 80 mass %, and still more preferably 30 mass % with respect to the entire styrenic polymer. to 70% by mass, more preferably 45 to 60% by mass, and particularly preferably 48 to 58% by mass. When attaching importance to formability, the content of the (meth)acrylic acid ester monomer unit (a2) is, for example, relative to the styrene-based polymerization The total content of the material is 7 to 35 mass%, preferably 7.5 to 30 mass%, more preferably 8 to 27 mass%, and still more preferably 8.5 to 25 mass%.

The preferred content of the (meth)acrylate monomer unit (a2) in this embodiment can be selected depending on the effect that is important. Especially when transparency is excellent, thinning during molding is suppressed or prevented, and deep drawing formability during molding is important, the content of the (meth)acrylate monomer unit (a2) is higher than that of the styrenic polymer. In total, 29 to 50 mass % is preferable, 30 to 47 mass % is more preferable, and 31 to 46 mass % is more preferable. On the other hand, while the transparency is maintained at a level visible from the outside (for example, the haze of a 0.3 mm sheet is 30% or less), thinning during molding is suppressed and prevented, and deep drawing formability during molding is emphasized. In the case of , the content of the (meth)acrylic acid ester monomer unit (a2) is preferably 7 to 18% by mass, more preferably 8.1 to 17% by mass, and further preferably 7 to 18% by mass, based on the entire styrenic polymer. 11 to 16.7% by mass.

In this embodiment, preferably, the styrene-based monomer is a copolymer of the styrene-based monomer (a1), the (meth)acrylic acid ester monomer (a2), and the (meth)acrylic acid ester monomer (a3). The difference (absolute value) between the refractive index of the polymer and the refractive index of the rubber-like polymer particles is 0 to 0.01, more preferably 0 to 0.005, and still more preferably 0 to 0.004 when transparency is important. On the other hand, when attaching importance to formability, the difference (absolute value) between the refractive index of the styrenic polymer and the refractive index of the rubber-like polymer particles is 0 to 0.01, more preferably 0.005 to 0.01, still more preferably is 0.006 to 0.01.

Furthermore, by setting the content of the (meth)acrylate monomer unit (a2) to 50% by mass or less, water absorption can be suppressed and the drying process can be simplified.

<(Meth)acrylate monomer unit (a3)>

In this embodiment, the (meth)acrylate monomer unit (a3) has a larger molecular weight than the (meth)acrylate monomer unit (a2), and specifically preferably has an alkyl chain with a carbon number of 4 to 6. (R ⁴ in the following general formula (2)) is a (meth)acrylate monomer unit as an ester substituent. At this time, the alkyl chain having 4 to 6 carbon atoms includes a linear, branched or cyclic alkyl group. Moreover, the preferred alkyl chain having 4 to 6 carbon atoms is preferably a linear or branched alkyl group, and examples thereof include n-butyl, tert-butyl, sec-butyl, and isobutyl. base, n-pentyl or n-hexyl, etc.

The (meth)acrylate monomer unit (a3) in this embodiment is preferably represented by the following general formula (2):

(In the above general formula (2), R ³ represents a hydrogen atom or an alkyl group having 4 to 6 carbon atoms, and R ⁴ represents an ester substituent, specifically an alkyl group having 4 to 6 carbon atoms.)

Furthermore, the (meth)acrylate monomer unit (a3) has a larger molecular weight than the (meth)acrylate monomer unit (a2). More specifically, the (meth)acrylate monomer unit (a3) is preferred. ) has a larger number of carbon atoms than the ester substituent of the (meth)acrylate monomer unit (a2).

In this embodiment, specific examples of the (meth)acrylate monomer (a3) include: (meth)acrylic acid n-butyl ester, (meth)acrylic acid second butyl ester, (meth)acrylic acid Isobutyl ester, tert-butyl (meth)acrylate, etc. Among these, from an industrial viewpoint, the (meth)acrylate monomer (a3) is preferably n-butyl (meth)acrylate, di-butyl (meth)acrylate, or (meth)acrylic acid. Isobutyl ester and tert-butyl (meth)acrylate.

In this embodiment, the content of the (meth)acrylate monomer unit (a3) in the entire styrene-based polymer is preferably adjusted so that the refractive index of the styrenic-based polymer becomes equal to that of the rubbery polymer. The absolute value of the difference in refractive index of the compound particles is within a predetermined range (for example, 0 to 0.01). The content of the (meth)acrylate monomer unit (a3) is, for example, 0.001 to 20 mass%, preferably 0.001 to 15 mass%, more preferably 0.1 to 14 mass%, based on the entire styrenic polymer. More preferably, it is 1 to 13 mass %, and still more preferably 4 to 12 mass %.

Furthermore, when attaching importance to the balance between transparency and heat resistance, the content range of the (meth)acrylic acid ester monomer unit (a3) is preferably 0.001 to 14 mass%, more preferably, based on the entire styrenic polymer. Preferably, it is 0.1 to 13% by mass, more preferably 1 to 12% by mass, still more preferably 2 to 11% by mass, and particularly preferably 3 to 10% by mass.

Furthermore, when attaching importance to the balance between deep drawing formability and thickness variation, the content range of the (meth)acrylate monomer unit (a3) is preferably 1 to 19 mass % with respect to the entire styrenic polymer. More preferably, it is 2 to 18% by mass, still more preferably 3 to 17% by mass, still more preferably 3.5 to 16% by mass, and particularly preferably 4 to 15% by mass.

Furthermore, as a preferred aspect of this embodiment, the lower limit of the total content of the (meth)acrylate monomer unit (a2) and the (meth)acrylate monomer unit (a3) in the entire styrene-based polymer is It is preferably 40 mass% or more, more preferably 40.5 mass% or more, still more preferably 41 mass% or more, still more preferably 41.5 mass% or more. On the other hand, the upper limit of the total content of the (meth)acrylate monomer unit (a2) and the (meth)acrylate monomer unit (a3) in the entire styrene-based polymer is preferably 50 mass % or less. More preferably, it is 49.5 mass% or less, still more preferably, it is 49 mass% or less, and still more preferably, it is 48.5 mass% or less. The above upper and lower limits can be combined arbitrarily.

By setting the total content of the (meth)acrylate monomer unit (a2) and the (meth)acrylate monomer unit (a3) in the entire styrene-based polymer within a specific range, it is possible to maintain a higher level While improving the transparency, it suppresses and prevents thinning during molding and exhibits the effect of more excellent deep drawing formability during molding.

The styrenic polymer in this embodiment only needs to be a ternary polymer containing a styrene monomer unit (a1), a (meth)acrylate monomer unit (a2), and a (meth)acrylate monomer unit (a3). The above copolymer is not particularly limited, but is preferably a ternary to quaternary copolymer. That is, the styrenic polymer in this embodiment is preferably a terpolymer containing a styrene monomer unit (a1) and two types of (meth)acrylate monomer units. This makes it possible to provide a styrene-based resin composition with a better balance of moldability, impact resistance, and transparency.

The styrenic polymer in this embodiment is preferably a linear or branched polymer, and among them, a substantially linear polymer is preferred. Therefore, the polymer matrix of this embodiment is preferably substantially composed of a linear styrenic polymer. This can suppress the generation of aggregates of styrene-based polymers, for example, gel-like materials formed by aggregation of styrene-based polymers, or precursors thereof. Therefore, when molding into containers or sheets, it is possible to suppress Perforations, cracks, etc. originating from a gel formed from a styrenic polymer or its precursor.

In addition, "substantially linear" means that it is a structural unit cell (or repeating unit cell) constituting the styrenic polymer and does not substantially include a branched structural unit cell or a structural unit cell or molecule of a polyfunctional compound. Conjugated divinyl-based monomer units having at least two conjugated vinyl groups. More specifically, the proportion of conjugated divinyl monomer units in the polymer matrix phase of this embodiment may be less than 2.0×10 ^-6 moles. More specifically, the content of the conjugated divinyl-based monomer units in the styrene-based resin composition of the present embodiment is relative to the styrene-based monomer (a1) and the (meth)acrylate monomer unit (a2). ) and the (meth)acrylate monomer unit (a3) is preferably less than 2.0 × 10 ^-6 mol per 1 mol. This can suppress punctures, cracks, etc. starting from the gel-like material made of the styrenic polymer or its precursor.

It should be noted that the conjugated vinyl group refers to a structure having an olefinic double bond copolymerizable with the styrene-based monomer (a1) and forming a conjugated system with the olefinic double bond (although there is no limitation, examples include a carbonyl group , aryl, etc.) groups. The conjugated vinyl group is not particularly limited, and examples thereof include an acryl group and a vinyl-substituted aryl group. In addition, as a structure having a conjugated vinyl group in the conjugated divinyl-based monomer unit, there are It is particularly limited, but examples thereof include structures obtained by adding (meth)acrylate, urethane (meth)acrylate, aromatic vinyl groups, maleic acid, fumaric acid, and the like.

The conjugated divinyl-based monomer unit in this embodiment refers to a compound having at least two conjugated vinyl groups in the molecule. In addition, the number average molecular weight (Mn) of the conjugated divinyl-based monomer unit is preferably 850 to 100,000.

Specific examples of the conjugated divinyl-based monomer include aromatic compounds having two or more vinyl groups such as divinylbenzene; (hydrogenated) polybutadiene terminal (meth)acrylate (" (Hydrogenated) refers to hydrogenated or unhydrogenated compounds. The same below), polyethylene glycol terminal (meth)acrylate, polypropylene glycol terminal (meth)acrylate, ethoxylated bisphenol A terminal (meth)acrylate Terminal di(meth)acrylate compounds such as methyl)acrylate and ethoxylated bisphenol F terminal (meth)acrylate; and (hydrogenated) polybutadiene terminal urethane acrylate, polyethylene glycol Alcohol-terminated urethane acrylate, polypropylene glycol-terminated urethane acrylate, ethoxylated bisphenol A-terminated urethane acrylate, and ethoxylated bisphenol F-terminated urethane acrylate Terminal urethane acrylate compounds such as acrylates, etc. In addition, "terminal" and "both ends" in the compound name mean that the conjugated vinyl group is located at at least one end or both ends.

Furthermore, the conjugated divinyl-based monomer unit in this embodiment is preferably chain-shaped rather than network-shaped, and may or may not have side chains on the main chain. This is because by forming the chain shape, the molecular chain can be formed into a more linear shape, thereby tending to easily enhance the entanglement effect. In addition, for example, the number of carbon atoms in a side chain is preferably 6 or less, and more preferably, the number of carbon atoms is 4 or less.

<Other single units>

The styrene-based polymer in this embodiment may also contain other monomer units copolymerizable with the styrene-based monomer (a1) as necessary. Examples of other monomer units that are optional components of the styrene-based polymer in this embodiment include (meth)acrylic acid monomer units. Examples of the (meth)acrylic acid monomer that constitutes the (meth)acrylic acid monomer unit include methacrylic acid, acrylic acid, maleic anhydride, maleic acid, fumaric acid, itaconic acid, and the like. In addition, when the styrene-based polymer contains (meth)acrylic acid monomer units, the content of the (meth)acrylic acid monomer units is relatively small relative to the entire styrene-based polymer (100% by mass). Preferably, it is greater than 0% by mass and less than or equal to 10% by mass, and more preferably, it is 0.1% by mass to 5% by mass.

Furthermore, the (meth)acrylate monomer (unit cell) (a2) and the (meth)acrylate monomer (unit cell) (a3), which are essential components of the styrene-based polymer, are combined with (methyl) The intermolecular interaction of the acrylic acid monomer (unit cell) also exerts the effect of suppressing the dehydration reaction of the (meth)acrylic acid monomer (unit cell) and improving the mechanical strength of the resin. Furthermore, the (meth)acrylate monomer (a2) and the (meth)acrylate monomer (a3) also contribute to the improvement of resin properties such as weather resistance and surface hardness.

It should be noted that when a (meth)acrylic acid monomer (unit cell) is selected as another monomer unit, the difference between the (meth)acrylic acid monomer (unit cell) and the (meth)acrylate ester monomer When (unit cell) (a2) or (meth)acrylate monomer (unit cell) (a3) are bonded adjacent to each other, when a high-temperature, high-vacuum devolatilization device is used, devolatilization may occur depending on the conditions. Alcohol reacts to form a six-membered cyclic acid anhydride. Although the styrenic polymer of this embodiment may contain the six-membered cyclic acid anhydride, it is preferable that less six-membered cyclic acid anhydride is produced because the fluidity is reduced.

<Preferred form of styrenic polymer>

Specific examples of the styrenic polymer in this embodiment include, for example, styrene-methyl acrylate-n-butyl acrylate copolymer, styrene-methyl acrylate-second butyl acrylate copolymer, benzene-methyl acrylate-n-butyl acrylate copolymer, Styrene-acrylic terpolymers such as ethylene-methyl acrylate-tert-butyl acrylate copolymer or styrene-methyl acrylate-isobutyl acrylate copolymer, more preferably styrene-methyl methacrylate- Butyl acrylate terpolymer or styrene-methyl acrylate-butyl methacrylate terpolymer.

In this embodiment, the styrenic polymer may be any of a random copolymer, a block copolymer, and an alternating copolymer. However, from the viewpoint of dispersion, a random copolymer is preferred.

Furthermore, in this embodiment, the styrenic polymer may be grafted onto the surface of the rubber-like polymer particles described below.

In this embodiment, the reduced viscosity of the styrenic polymer or polymer matrix phase is not particularly limited, but is preferably 0.6 or more and 1.0 or less, more preferably 0.7 or more and 0.9 or less. When the reduced viscosity is less than 0.6, the impact strength of the composition may decrease. When it exceeds 1.0, the resin viscosity becomes high and the formability decreases. In addition, the measurement method of the reduced viscosity in this invention is performed by the method described in the paragraph of "Examples".

The melt mass flow rate (MFR) of the entire styrenic resin composition in this embodiment is 1.5g/10min to 5g/10min, preferably 1.8g/10min to 4.5g/10min, more preferably It is 2g/10 minutes to 4g/10 minutes. It should be noted that styrenic polymers Or the melt mass flow rate of the polymer matrix phase is a value measured at 200°C and 49N in accordance with JIS K 7210-1.

When the melt mass flow rate (MFR) of the entire styrenic resin composition is less than 1.5 g/10 minutes, productivity is poor due to insufficient fluidity. On the other hand, when the melt mass flow rate (MFR) exceeds 5 g/10 minutes, the fluidity is too high and the container formability is poor.

<Molecular weight of styrenic polymer>

In this embodiment, the weight average molecular weight (Mw) of the styrenic polymer is 100,000 to 300,000, preferably 150,000 to 300,000, more preferably 150,000 to 270,000, still more preferably 150,000 to 270,000. 10,000 to 240,000. When the weight average molecular weight is less than 100,000, the impact strength of the styrenic resin composition may decrease. When the weight average molecular weight exceeds 300,000, the fluidity of the styrenic resin composition decreases, which may hinder productivity.

Furthermore, when transparency is important, the weight average molecular weight (Mw) of the styrenic polymer is preferably 100,000 to 240,000, more preferably 100,000 to 200,000, still more preferably 100,000 to 190,000. , the best range is 100,000 to 180,000, and the best range is 100,000 to 170,000.

Furthermore, when paying attention to the balance between deep drawing formability and thickness variation, the weight average molecular weight (Mw) of the styrenic polymer is preferably 110,000 to 300,000, more preferably 120,000 to 270,000, and The best range is 130,000 to 260,000, the even better range is 140,000 to 250,000, and the best range is 150,000 to 240,000.

In addition, the measuring method of the weight average molecular weight in this invention is performed by the method described in the paragraph of "Examples".

In this embodiment, the number average molecular weight (Mn) of the styrenic polymer is 40,000 to 120,000, preferably 45,000 to 120,000, more preferably 50,000 to 115,000, still more preferably 5 10,000 to 110,000.

When the number average molecular weight is less than 40,000, the impact strength of the styrenic resin composition may decrease. When the number average molecular weight exceeds 120,000, the fluidity of the styrenic resin composition decreases, which may hinder productivity.

Furthermore, when transparency is important, the number average molecular weight (Mn) of the styrenic polymer is preferably 45,000 to 90,000, more preferably 45,000 to 85,000, still more preferably 45,000 to 80,000. , even better is 45,000 to 75,000, extra best is 45,000 to 70,000.

Furthermore, when paying attention to the balance between deep drawing formability and thickness variation, the number average molecular weight (Mn) of the styrenic polymer is preferably 50,000 to 120,000, more preferably 55,000 to 120,000, and The best range is 60,000 to 120,000, the even better range is 60,000 to 115,000, and the best range is 65,000 to 110,000.

In addition, the measurement method of the number average molecular weight in this invention is carried out by the method described in the paragraph of "Examples".

In this embodiment, the number average molecular weight (Mn) of the styrenic polymer is 60,000 to 120,000, and the weight average molecular weight (Mw) of the styrenic polymer is 150,000 to 300,000. When the styrenic polymer constituting the polymer matrix phase contains a large amount of low molecular weight components, the number average molecular weight (Mn) itself tends to become smaller and the entanglement of molecules becomes less, so the mechanical strength is likely to deteriorate. On the other hand, the weight average molecular weight (Mw) of the styrenic polymer constituting the polymer matrix phase does not depend on the position of the peak top, and shows a tendency not to be affected by low molecular weight components. Therefore, by controlling both the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the styrene-based polymer, the melt viscosity that affects the formability can be easily controlled.

In the styrene-based resin composition of this embodiment, it was found that by controlling the molecular weight distribution of the polymer matrix phase containing the styrene-based polymer, thickness variation and the generation of gelatinous matter during container molding were suppressed and maintained. It achieves transparency above a certain level and exhibits superior deep drawing formability during forming. Specifically, by polymerizing the proportion of so-called high molecular weight components (styrenic polymers having a molecular weight of more than a specific molecular weight, particularly 700,000, 800,000, and 1,000,000 or more) in the polymer matrix phase containing the styrenic polymer. The proportion of materials) is controlled at a specific ratio, which suppresses thickness deviations and the generation of gelatin during container molding, maintains transparency above a certain level, and shows better deep drawing formability during molding.

In the styrene-based resin composition of this embodiment, when the polymer matrix containing the styrene-based polymer is phase-divided into a high molecular weight component of 700,000 or more and a molecular weight component of less than 700,000, relative to the polymer In the matrix phase (overall), the proportion of high molecular weight components above 700,000 in the polymer matrix phase is preferably 0.15% to 5%, more preferably 0.4% to 4%.

When the proportion of the high molecular weight component of 700,000 or more is 0.4% to 4% relative to the polymer matrix phase (whole body), it is preferable from the viewpoint of suppressing thickness variation during container molding.

In the styrene-based resin composition of this embodiment, when the polymer matrix containing the styrene-based polymer is phase-divided into a high molecular weight component of 800,000 or more and a molecular weight component of less than 800,000, relative to the polymer In the matrix phase (whole body), the proportion of high molecular weight components above 800,000 in the aforementioned polymer matrix phase is preferably 0.1% to 3.0%, more preferably 0.2% to 2.5%.

When the proportion of the high molecular weight component of 800,000 or more is 0.4% to 3.0% with respect to the polymer matrix phase (whole body), it is preferable from the viewpoint of suppressing thickness variation during container molding.

In the styrenic resin composition of this embodiment, the polymer matrix containing the styrenic polymer is phase-divided into a high molecular weight component of 1 million or more and a molecular weight component of less than 1 million. In the case of , relative to the polymer matrix phase (the whole), the proportion of high molecular weight components of more than 1 million in the polymer matrix phase is preferably less than 1.0%, more preferably less than 0.95%, and more preferably less than 0.95%. Accounting for 0.3% to 0.9%.

When the proportion of the high molecular weight component of 1 million or more is 1.0% or more relative to the polymer matrix phase (the whole), the following disadvantage occurs: gelatinous matter is easily generated, and the gelatinous matter becomes the starting point during container molding. damaged. Therefore, from the viewpoint of suppressing thickness variation during container molding and suppressing the generation of gel matter, it is preferable to control the proportion of high molecular weight components of 1 million or more in the polymer matrix phase.

In this specification, the calculation method of the ratio of the high molecular weight component of 700,000 or more, the high molecular weight component of 800,000 or more, and the high molecular weight component of 1,000,000 or more constituting the polymer matrix phase of the styrenic resin composition is as described in the Examples below. As shown in the paragraph, GPC was used to measure the molecular weight of the polymer matrix phase (other than the rubber-like polymer particles) of the styrenic resin composition, and the vertical axis was the differential distribution value and the horizontal axis was Log ₁₀ M (molecular weight (M)). (Logarithm) of the molecular weight distribution curve, find the area of the molecular weight distribution curve with a molecular weight (M) of 1 million or more (see Figure 5).

<Polymerization method of styrenic polymer>

In this embodiment, the polymerization method of the styrene-based polymer is not particularly limited. For example, as a radical polymerization method, a bulk polymerization method or a solution polymerization method can be preferably used. The polymerization method mainly includes a polymerization step of polymerizing polymerization raw materials (monomer components) and a devolatilization step of removing volatile components such as unreacted monomers and polymerization solvents from the polymerization product.

Hereinafter, an example of a polymerization method of a styrene-based polymer that can be used in this embodiment will be described.

When polymerizing raw materials to obtain a styrenic polymer, a polymerization initiator and a chain transfer agent are usually included in the polymerization raw material composition.

Examples of polymerization initiators used in polymerization of styrenic polymers include organic peroxides, such as 2,2-bis(tert-butylperoxy)butane, 1,1-bis( Peroxide ketals such as tert-butylperoxy)cyclohexane, 4,4-bis(tert-butylperoxy)n-butyl valerate; di-tert-butyl peroxide, tert-butyl peroxide Dialkyl peroxides such as butyl cumyl peroxide and dicumyl peroxide; dialkyl peroxides such as acetyl peroxide and isobutyl peroxide; diisopropyl peroxydicarbonate and other peroxides Oxidized dicarbonates; peroxyesters such as tert-butyl peracetate; peroxyketones such as acetyl acetone peroxide, hydroperoxides such as tert-butyl hydroperoxide, etc. From the viewpoint of decomposition speed and polymerization speed, 1,1-bis(tert-butylperoxy)cyclohexane is preferred among them.

Examples of the chain transfer agent used in polymerization of styrene-based polymers include α-methylstyrene linear dimer, n-dodecylmercaptan, tertiary-dodecylmercaptan, n-dodecylmercaptan, Octylmercaptan, etc.

As a polymerization method of the styrenic polymer, solution polymerization using a polymerization solvent can be used if necessary. Examples of the polymerization solvent used include aromatic hydrocarbons such as ethylbenzene; dialkyl ketones such as methyl ethyl ketone; each of them may be used alone, or two or more types may be used in combination. Other polymerization solvents such as aliphatic hydrocarbons may be further mixed with the aromatic hydrocarbons as long as the solubility of the polymerization product is not reduced. These polymerization solvents are preferably used in a range of no more than 25 parts by mass relative to 100 parts by mass of all monomers. When the polymerization solvent exceeds 25 parts by mass relative to 100 parts by mass of the total monomers, the polymerization speed tends to significantly decrease, and the mechanical strength of the resulting resin tends to decrease significantly. Before aggregation, relative to 100 When the polymerization solvent is added in advance in a proportion of 5 to 20 parts by mass of all the monomers, the quality can be easily uniformized, and the polymerization temperature can be controlled well.

In this embodiment, the apparatus used in the polymerization step for obtaining a styrene-based polymer is not particularly limited, and can be appropriately selected based on a known polymerization method. For example, when monolithic polymerization is adopted, a single complete mixing reactor or a polymerization device in which a plurality of complete mixing reactors are connected can be used. Furthermore, there is no particular restriction on the devolatilization process. In the case of bulk polymerization, the polymerization is carried out until the final unreacted monomer is preferably 50% by mass or less, more preferably 40% by mass or less. In order to remove volatile components such as the unreacted monomer, a known method is used Carry out devolatilization treatment. More specifically, for example, a general devolatilizer such as a flash tank, a twin-screw devolatilizer, a thin film evaporator, and an extruder can be used, and a devolatilizer with fewer retention parts is preferred. It should be noted that the temperature of the devolatilization treatment is usually about 190°C to about 280°C, and more preferably 190°C to 260°C. Furthermore, the pressure of devolatilization treatment is usually about 0.13kPa to about 4.0kPa, preferably 0.13kPa to 3.0kPa, more preferably 0.13kPa to 2.0kPa. Preferable devolatilization methods include, for example, a method of removing volatile components by reducing pressure under heating, and a method of removing using an extruder designed for the purpose of removing volatile components.

(Rubber-like polymer particles)

In this embodiment, the styrenic resin composition contains rubber-like polymer particles (referred to as rubber-like polymer particles in this specification). As a result, mechanical properties such as impact resistance can be improved as a whole for the styrene-based resin composition.

The styrenic resin composition of this embodiment preferably has a sea-island structure in which rubber-like polymer particles are dispersed in a polymer matrix phase as a continuous phase. As a result, it has excellent mechanical strength.

The rubbery polymer particles of this embodiment are preferably formed from a conjugated diene monomer. In this specification, the conjugated diene monomer (unit cell) refers to a diene having a pair of conjugated double bonds among the monomer units constituting the rubber-like polymer particles. Examples thereof include: 1,3- Butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3 -Hexadiene, etc.

The rubber-like polymer particles in the present invention may be particles containing a rubber-like polymer. Therefore, the forms of rubber-like polymer particles include: solid particles made of rubber-like polymer; hollow particles made of rubber-like polymer; and polystyrene or styrenic polymer contained in rubber-like polymer. Phase-encapsulated particles (including microphase separation structure, core-shell structure and salami-type structure), the aforementioned styrene-based polymer has styrene-based monomer unit (a1), (meth)acrylate monomer unit (a2) and (meth)acrylate monomer unit (a3); and surface-grafted particles having the aforementioned polystyrene or the aforementioned styrenic polymer grafted onto the surface. In addition, these forms can also be combined.

Preferred forms of rubber-like polymer particles include solid particles made of a rubber-like polymer on which polystyrene is grafted onto the surface or styrene-based monomer units (a1) and (methyl) are grafted on the surface. Surface-grafted particles of a styrenic polymer of an acrylate monomer unit (a2) and a (meth)acrylate monomer unit (a3), containing the aforementioned polystyrene or the aforementioned polystyrene in a rubbery polymer A surface graft obtained by grafting the aforementioned polystyrene or the aforementioned styrenic polymer onto the surface of particles (including microphase separation structures, core-shell structures, and salami-type structures) contained in the styrenic polymer phase. Branches enclose particles. Among these, the rubber-like polymer particles are preferably the above-mentioned surface-grafted particles, inner-wrapped particles (including microphase separation structure, core-shell structure, and salami-type structure) and surface-grafted inner-wrapped particles. particle.

In addition, the above-mentioned enclosed particles include the following structures (1) to (2).

(1) Polymerization of styrene containing polystyrene or having a styrene monomer unit (a1), a (meth)acrylate monomer unit (a2), and a (meth)acrylate monomer unit (a3) The core-shell structure uses the physical phase as the core and the rubber-like polymer as the shell.

(2) A styrenic polymer containing polystyrene or having a styrenic monomer unit (a1), a (meth)acrylate monomer unit (a2), and a (meth)acrylate monomer unit (a3) The phase consists of a plurality of salami-type structures enclosed in a rubbery polymer.

"Polystyrene" in the above (1) to (2) refers to the homopolymer of the styrene-based monomer unit (a1).

The rubber-like polymer particles in the present invention are particularly preferably those containing polystyrene or having styrenic monomer units (a1), (meth)acrylate monomer units (a2) and (meth)acrylate monomer units. The styrenic polymer of (a3) is a salami-type structure in which a plurality of phases of the styrene-based polymer are enclosed in a rubber-like polymer.

In addition, the said rubber-like polymer particle containing a rubber-like polymer means that the rubber-like polymer accounts for 5 mass % or more of the whole rubber-like polymer particle.

In this embodiment, among all the rubber-like polymer particles contained in the styrenic resin composition, it is preferable that at least 21 volume % of the rubber-like polymer particles have a salami-type structure, and more preferably More than 50% by volume has a salami-type structure, and more preferably 75 to 95% by volume has a salami-type structure. As a result, impact resistance is excellent.

It should be noted that in this specification, among all rubber-like polymer particles contained in the styrene-based resin composition, the rubber-like polymer particles with a salami type structure and the rubber-like polymer particles with a core-shell structure are included. The measurement method of the rate is calculated by observing with an electron microscope according to the following method.

Five 100 nm thick ultrathin sections were prepared from the osmium tetroxide-stained styrenic resin composition, and 10 bright-field images with a magnification of 10,000 times were randomly obtained using a transmission electron microscope. , particles dyed black are rubber-like polymer particles, and particles containing two or more phases in the rubber-like polymer particles are judged to be rubber-like polymer particles with a salami-type structure. On the other hand, particles containing one phase in the rubbery polymer particles were determined to be rubbery polymer particles having a core-shell structure. Furthermore, the particle diameter of the rubber-like polymer particles captured in the 10 images was measured and calculated according to the following equation.

Content rate of rubber-like polymer particles with salami type structure (volume %) = Σmidi ³ /Σnidi ³

(In the above formula, ni represents the number of rubber-like polymer particles with a particle size di, and mi represents the number of rubber-like polymer particles with a salami-type structure having a particle size di.)

In other words, among all the rubber-like polymer particles contained in the styrenic resin composition of the present embodiment, it is preferable that less than 79 volume % of the rubber-like polymer particles have a core-shell structure.

This results in excellent impact strength.

In this embodiment, the proportion of graft chains (grafting rate) in the polystyrene or styrenic polymer that graft-copolymerizes the rubber-like polymer is 5% to 100%, preferably 15% to 100%. 90%, preferably 20% to 85%, and even more preferably 18% to 60%.

When the grafting rate is 15% or more, it is preferable from the viewpoint of impact resistance, and when it is 65% or less, it is preferable from the viewpoint of fluidity.

The calculation method of the graft ratio of the above-mentioned polystyrene or styrenic polymer is as follows. The solvent-soluble components are removed from the styrenic resin composition using a solvent (toluene, etc.), and the solvent-insoluble components (graft component content) are taken out and measured with a Fourier transform infrared spectrophotometer (FT-IR) to measure rubber. The mass of the colloidal polymer and the graft component (that is, the graft-polymerized monomer) can be obtained by calculating the ratio of the mass of the graft-polymerized monomer to the mass of the rubber-like polymer from this equivalent value.

It should be noted that the grafting rate of polystyrene or styrenic polymer can be controlled by adjusting polymerization conditions, the type or amount of polymerization initiator and chain transfer agent, and the like.

In this embodiment, it is preferable that 60% or more of the total number of rubber-like polymer particles present in the styrenic resin composition are enclosed with a polymer phase containing a styrenic polymer, and more preferably 80% or more of the total number of rubber-like polymer particles present in the styrenic resin composition is enclosed. There is a polymer phase containing styrenic polymers. In addition, more than 60% of the total number of rubber-like polymer particles present in the styrene-based resin composition contains polystyrene and/or has a styrene-based monomer unit (a1), a (meth)acrylate monomer unit ( A salami-type structure in which the styrene-based polymer phases of a2) and the (meth)acrylate monomer unit (a3) are enclosed in a plurality of rubber-like polymer particles. In addition, in this embodiment, the lower limit of the proportion of the salami-type structure in the rubber-like polymer particles in the styrene-based resin composition is 70% or more, 80% or more, 85% or more, or 90%. The order of above and above 95% is better. On the other hand, the upper limit of the proportion of the salami-type structure is more preferably in the order of 100% or less, 99% or less, and 98% or less.

This makes it possible to provide a styrene-based resin composition that is more excellent in impact resistance, folding resistance, and transparency.

The calculation method of the number of polymer phases containing the styrenic polymer and the proportion of the salami-type structure in the rubber-like polymer particles in the styrenic resin composition is the same as that of the rubber-like polymer particles described below. The weight average diameter is calculated similarly, using a transmission electron microscope and measuring the number average. Specifically, five 100 nm thick ultrathin sections were prepared from a styrene-based resin composition stained with osmium tetroxide, and 10 arbitrarily obtained 10 magnification sections were obtained using a transmission electron microscope. Among the 10 images obtained after magnifying the bright field image at 10,000 times, the particles stained black are rubber-like polymer particles, and the particles containing two or more phases in the rubber-like polymer particles are judged to be Sara. Rubber-like polymer particles with a rice-shaped structure are converted into Calculated as a percentage.

In the styrene-based resin composition of the present embodiment, the upper limit of the content of the rubber-like polymer particles (including the polymer phase containing the styrene-based polymer. Also called toluene-insoluble content) is relative to the styrene-based resin. The total amount of the composition is 100 mass%, preferably 57 mass% or less, 52 mass% or less, 45 mass% or less, 42 mass% or less, 41 mass% or less, 40 mass% or less, 38 mass% or less, 36 mass% Below, below 34 mass%, below 32 mass%, below 30 mass%, below 29 mass%, below 28 mass%, below 27 mass%, below 26 mass%, below 25 mass%, below 24 mass%, 23 mass% or less, 22 mass% or less, 21 mass% or less, 20 mass% or less, 19 mass% or less. On the other hand, in the styrenic resin composition of the present embodiment, the lower limit of the content of the rubber-like polymer particles is preferably 3 mass % or more, 4 Mass% or more, 5 mass% or more, 6 mass% or more, 7 mass% or more, 8 mass% or more, 9 mass% or more, 10 mass% or more. These upper and lower limits can each be combined arbitrarily.

In the styrene-based resin composition of the present embodiment, the preferred range of the content of the rubber-like polymer particles (including the portion included in the polymer phase including the styrene-based polymer. Also referred to as toluene-insoluble components) It is 5 mass % or more and 55 mass % or less, preferably 10 mass % or more and 45 mass % or less, more preferably 15 mass % or more and 35 mass % with respect to 100 mass % of the total amount of the styrenic resin composition. or less, and more preferably 16 mass% or more and 30 mass% or less. borrow By setting the content to 5 mass % or more and 55 mass % or less, it is easy to achieve both excellent impact resistance and rigidity.

The content of the "rubbery polymer particles" in this specification (including the polymer phase containing the styrenic polymer (toluene-insoluble component)) is measured by the following method.

The content (mass %) of the rubber-like polymer particles in the styrenic resin composition or styrenic resin (A) is measured as follows. Accurately weigh 1 g of the styrene-based resin composition or styrene-based resin (A) in a sedimentation tube (let this mass be Wt), add 20 mL of toluene solution, shake at 23°C for 2 hours, and use a centrifuge (Sakuma Seisakusho Co., Ltd. Manufactured by the company, SS-2050A), centrifuge for 60 minutes at 5°C or below and 20,000 rpm (centrifugal acceleration: 4510G). Slowly tilt the sedimentation tube at about 45 degrees, decant to remove the supernatant, and then vacuum-dry the obtained insoluble components at 160°C and 3kPa or less for 1 hour. After cooling to room temperature in a desiccator, accurately weigh the toluene. The mass of the insoluble component (let this mass be Gt) and the content (mass %) of the rubber-like polymer particles were determined by the following formula.

Content of rubbery polymer particles (= toluene-insoluble content) = (Gt/Wt) × 100

The upper limit of the content of the rubber-like polymer particles (including the polymer phase containing the styrenic polymer. (Methyl ethyl ketone/methanol = 9/1 insoluble components, the same ratio applies below)) in the styrenic resin composition of the present embodiment. Preferably, it is 55 mass% or less, 52 mass% or less, 51 mass% or less, 50 mass% or less, 48 mass% or less, 46 mass% or less, 44 mass% relative to 100 mass% of the total amount of the styrenic resin composition. % or less, 42 mass% or less, 40 mass% or less, 39 mass% or less, 38 mass% or less, 37 mass% or less, 36 mass% or less, 35 mass% or less, 34 mass% or less, 33 mass% or less, 32 mass% % or less, 31 mass% or less, 30 mass% or less, 29 mass% or less. On the other hand, in the styrene-based resin composition of this embodiment, the lower limit of the content of the rubber-like polymer particles is relative to the total amount of the styrenic-based resin composition. 100 mass%, preferably 5 mass% or more, 5.4 mass% or more, 6 mass% or more, 6.6 mass% or more, 7 mass% or more, 7.3 mass% or more, 8 mass% or more, 8.6 mass% or more, 9 mass% More than 9.4 mass % or more, 9.9 mass % or more, 10 mass % or more, 10.3 mass % or more, 11 mass % or more, 12 mass % or more, 13 mass % or more, 14 mass % or more, 14.1 mass % or more, 15 mass % or more More than 16% by mass, more than 17% by mass. These upper and lower limits can each be combined arbitrarily.

Furthermore, a preferable range of the content of the rubber-like polymer particles (including the polymer phase including the styrene-based polymer (methyl ethyl ketone/methanol-insoluble components)) of the present embodiment is, for example, relative to the total content of the styrenic-based resin composition. The amount is 100 mass%, and it is 5 mass% or more and 55 mass% or less, preferably 10 mass% or more and 45 mass% or less, more preferably 15 mass% or more and 35 mass% or less, and still more preferably 16 mass% or more. And less than 30% by mass. By setting the content to 5 mass % or more and 55 mass % or less, it is easy to achieve both excellent impact resistance and rigidity.

Furthermore, a preferable range of the content of the rubber-like polymer particles (including the polymer phase including the styrene-based polymer (methyl ethyl ketone/methanol-insoluble components)) of the present embodiment is, for example, relative to the total content of the styrenic-based resin composition. The amount is 100 mass%, and it is 5 mass% or more and 55 mass% or less, preferably 10 mass% or more and 45 mass% or less, more preferably 15 mass% or more and 35 mass% or less, and still more preferably 16 mass% or more. And less than 30% by mass. By setting the content to 5 mass % or more and 55 mass % or less, it is easy to achieve both excellent impact resistance and rigidity.

The content of the rubber-like polymer particles in this specification (including the polymer phase containing the styrene-based polymer (methyl ethyl ketone/methanol-insoluble component)) is measured by the following method.

The content (mass %) of the rubber-like polymer particles in the styrenic resin composition or styrenic resin (A) is measured as follows. Accurately weigh the styrenic resin composition or styrene in the settling tube 1g of resin (A) (let this mass be W), add 20mL of methyl ethyl ketone/methanol = 9/1 solution, shake at 23°C for 2 hours, and use a centrifuge (SS-2050A, manufactured by Sakuma Seisakusho Co., Ltd.) at 5 Centrifuge at 20,000 rpm (centrifugal acceleration: 4510G) for 60 minutes below ℃. Slowly tilt the sedimentation tube at about 45 degrees, decant to remove the supernatant, and then vacuum-dry the obtained insoluble components at 160°C and 3kPa or less for 1 hour. After cooling to room temperature in a desiccator, accurately weigh the methyl ethyl ketone. /The mass of the methanol-insoluble component (let this mass be G), the content (mass %) of the rubber-like polymer particles was determined by the following formula.

Content of rubbery polymer particles (=methyl ethyl ketone/methanol insoluble components) = (G/W) × 100

In the styrene-based resin composition of this embodiment, the content of the rubber-like polymer constituting the rubber-like polymer particles (excluding styrene-based resin composition) relative to the total amount of the styrene-based resin composition (100% by mass) The inner part of the polymer phase of the polymer) is preferably 3 to 23 mass %, more preferably 6 to 16 mass %, and still more preferably 7 to 15 mass %. When the content of the rubber-like polymer is less than 3% by weight, the impact absorption effect becomes smaller, so the impact resistance decreases. When the content of the rubber-like polymer exceeds 23% by mass, problems such as fluidity or heat resistance may decrease.

Furthermore, when transparency is important, the content of the rubber-like polymer is preferably 5 to 15 mass %, more preferably 5.5 to 15 mass % with respect to the total amount of the styrenic resin composition (100 mass %). %, more preferably 6 to 15 mass %, still more preferably 6.5 to 15 mass %, particularly preferably 7 to 15 mass %.

Furthermore, when attaching importance to moldability, the content of the rubbery polymer is preferably 7 to 17 mass %, more preferably 7.5 to 17 mass % with respect to the total amount of the styrenic resin composition (100 mass %). % by mass, more preferably 8 to 17 % by mass, more preferably 9 to 17 % by mass, particularly preferably 10 to 17 % by mass.

In the styrenic resin composition of this embodiment, the conjugated diene monomer units in the rubber-like polymer constituting the rubber-like polymer particles are The content of is preferably 3 to 13% by mass, more preferably 4 to 12% by mass, and still more preferably 5 to 11% by mass. When the content of the conjugated diene monomer unit is less than 3% by mass, the impact absorption effect becomes smaller, so the impact resistance decreases. When the content of the conjugated diene monomer unit exceeds 13% by mass, problems such as decreased fluidity or decreased heat resistance may occur.

In this specification, the content of the conjugated diene monomer units constituting the rubber-like polymer particles (rubber content) is measured by the method described in the section "Examples". On the other hand, in this specification, the measurement method of the content of rubber-like polymer particles (rubber content) is calculated from the charging amount.

In this specification, the content of the conjugated diene monomer units calculated by the above is the content of the rubber-like polymer derived from the styrenic resin composition, excluding polymerization that may be encapsulated in the rubber-like polymer particles. Physical phase (styrenic polymer and/or polystyrene). That is, the rubber content represents the content of the conjugated diene monomer unit (for example, the substantial amount of butadiene).

The rubber-like polymer particles in this embodiment preferably include a polymer phase containing a styrenic polymer and/or polystyrene. This can further improve impact resistance and rigidity. Furthermore, in the styrene-based resin composition in this embodiment, it is preferable that at least 80 mass % of the rubber-like polymer particles are enclosed in the rubber-like polymer particles, and the above-mentioned styrene-based polymer and/or Or the polymer phase of polystyrene is occupied, more preferably, 80 mass % or more and 95 mass % or less of the rubber-like polymer particles are occupied by the polymer phase.

In addition, the measurement of the content of the polymer phase containing the styrenic polymer enclosed in the rubber-like polymer particles is the value obtained by subtracting the rubber content from the content of the rubber-like polymer particles.

The material used for the rubber-like polymer particles (or rubber-like polymer) of this embodiment may be any material having a conjugated diene structure (conjugated diene-based monomer unit). Therefore, the rubber-like polymer in this embodiment is preferably a conjugated diene-based polymer. For example, polybutadiene, polyisoprene, natural rubber, polychloroprene, and styrene-butadiene can be used. olefin copolymer, acrylonitrile-butadiene copolymer, etc. Among them, polybutadiene or styrene-butadiene copolymer is preferred. For polybutadiene, two types of high cis polybutadiene, which has a high cis content, and low cis polybutadiene, which has a low cis content, can be used. In addition, the polybutadiene may have a styrene-butadiene copolymer and/or an acrylonitrile-butadiene copolymer in part or all of the polybutadiene. As the structure of the styrene-butadiene copolymer and the acrylonitrile-butadiene copolymer, two types of random structure and block structure can be used. One type or two or more types of these rubber-like polymer particles may be used.

In this embodiment, a conjugated diene polymer containing a cyanide vinyl monomer unit such as a (meth)acrylonitrile monomer unit is used as the rubber-like polymer particles (or rubber-like polymer). In the case of materials, the content of the vinyl cyanide monomer unit is preferably 5 mass% or less, more preferably 3 mass% or less, and still more preferably 1 mass% relative to the entire styrenic resin composition (100 mass%). mass% or less, particularly preferably 0.7 mass% or less.

Furthermore, saturated rubber obtained by hydrogenating the above-mentioned butadiene rubber, natural rubber, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer can also be used as the rubber-like polymer particles. In addition, as the structure of the styrene-butadiene copolymer rubber, two types of random structure and block structure can be used. One type or two or more types of these rubbery polymers may be used. In the case where a styrene-butadiene copolymer is used as the rubbery polymer, the styrene monomer unit in the styrene-butadiene copolymer The content of is preferably 50 mass% or less, more preferably 40 mass% or less. As the content of styrene monomer units in the styrene-butadiene copolymer increases, the refractive index difference with the polymer matrix phase tends to become smaller.

When polybutadiene is selected as the rubber-like polymer constituting the rubber-like polymer particles in this embodiment, the content of the rubber-like polymer constituting the rubber-like polymer particles is relatively high relative to the entire styrenic composition. Preferably, it is about 5 to 13% by mass, and more preferably, it is about 8 to 11% by mass.

On the other hand, when a styrene-butadiene copolymer is selected as the rubber-like polymer constituting the rubber-like polymer particles, the content of the rubber-like polymer relative to the entire styrenic composition is preferably about 10 to 23% by mass, more preferably about 11 to 19% by mass.

When the rubber-like polymer in the rubber-like polymer particles is within the above range, excellent impact resistance can be exhibited.

In this embodiment, the average particle diameter of the rubber-like polymer particles contained in the styrenic resin composition is preferably 0.4 μm or more and 0.95 μm or less.

This makes it easy to achieve both excellent impact resistance and strength. Although the detailed reason is unclear, when the thickness is below 0.4 μm, the practical strength of a sheet such as rigidity, impact resistance, and folding resistance is poor, and the balance between rigidity and strength is poor. When the thickness exceeds 0.95 μm, the transparency becomes poor. The stability is significantly reduced, so the balance between transparency and impact resistance is poor.

In the styrene-based resin composition according to the present invention, the average particle diameter of the entire rubber-like polymer particles contained in the styrene-based resin composition is 0.4 μm or more and 0.95 μm or less, and the rubber-like polymer particles (dispersed ) is present in the matrix resin of the styrenic resin composition, the stress field in the matrix resin in which the rubber-like polymer particles are present becomes non-uniform. From this, it is inferred that local deformation (shear yield deformation and/or microcrack deformation) occurs around the rubber-like polymer particles. The rubber-like polymer particles absorb external energy by causing connections between the particles, thereby achieving both excellent impact resistance and rigidity.

The method for measuring the average particle diameter (μm) of the rubber-like polymer particles in this specification uses the method described in the section of Examples to be described later.

In this embodiment, the lower limit of the average particle diameter of the rubber-like polymer particles contained in the styrenic resin composition is preferably 0.4 μm or more, 0.45 μm or more, 0.5 μm or more, or 0.53 μm or more. The upper limit of the weight average diameter of all the rubber-like polymer particles is preferably 0.95 μm or less, 0.88 μm or less, 0.76 μm or less, or 0.71 μm or less. The upper limit and the lower limit of the average particle diameter in the range of the average particle diameter can be combined arbitrarily.

In this embodiment, the rubber-like polymer particles are preferably in the form of surface-grafted inner particles having a styrene-(meth)acrylate copolymer or a styrene-(meth)acrylate copolymer. Polybutadiene or polybutadiene-styrene copolymer is obtained by grafting ester-butyl (meth)acrylate copolymer on the surface, containing styrene-methyl (meth)acrylate copolymer. Or at least one surface of the styrene-methyl(meth)acrylate-butyl(meth)acrylate copolymer phase is grafted with inner particles, and the rubber-like polymer particles have a diameter of 0.40 μm or more and 0.95 μm or less. average particle size within the range.

The styrene-based resin composition of the present embodiment more preferably has a sea-island structure including rubber-like polymer particles containing a rubber-like polymer with an average particle diameter in the range of 0.4 μm to 0.95 μm, and constituent polymers. Styrenic polymer in matrix phase.

In this case, in this embodiment, the surface-grafted inclusion particles are preferably contained in an amount of 5 to 40 mass %, and more preferably 10 to 40 mass % of the entire styrenic resin composition (100 mass %). 35% by mass. When the content is less than 5% by mass, although the fluidity is good, impact resistance and folding resistance are not easily developed. When the content exceeds 40% by mass, the appearance such as fluidity and transparency decreases.

(higher fatty acid compounds)

The styrenic resin composition of this embodiment contains a higher fatty acid compound as needed. This suppresses and prevents thinning during molding and exhibits an effect of further excellent deep drawing formability during molding.

Examples of the higher fatty acid compound include esters of higher fatty acids and higher alcohols (for example, myristyl myristate, stearyl stearate, octyldodecyl behenate, beryl behenate). Esters), esters of higher fatty acids and sorbitan (sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan distearate, sorbitan Monoberate), esters of higher fatty acids and glycerin (glyceryl monostearate, glyceryl distearate, glyceryl tristearate, glyceryl myristate, glyceryl palmitate, behenic acid Glyceryl ester, glyceryl oleate), or hardened oil (tallow extremely hardened oil, castor hardened oil). The higher fatty acid compound may be used alone or in combination of two or more types.

In the styrenic resin composition of this embodiment, the content of the higher fatty acid compound is preferably 0 to 0.7 mass %, more preferably 0.03 to 0.7 with respect to the total amount of the styrenic resin composition (100 mass %). Mass % is more preferably 0.05 to 0.65 mass %, still more preferably 0.07 to 0.6 mass %, and further preferably 0.1 to 0.55 mass %.

(Plasticizer)

The styrenic resin composition of this embodiment may contain a known plasticizer other than a higher fatty acid compound as needed. Specific examples of the plasticizer include, from the viewpoint of thermal stability, liquid paraffin or aliphatic or cyclic hydrocarbons (for example, nonane, decane, decalin, parabis Toluene, undecane or dodecane), silicone oil. Among them, liquid paraffin is more preferred as the plasticizer in this embodiment.

In the styrene-based resin composition of this embodiment, the content of the plasticizer is preferably 0.05 mass% or more and 5 mass% or less, more preferably 0.1 mass%, based on 100 mass% of the total amount of the styrene-based resin composition. % or more and 2.8 mass% or less, more preferably 0.15 mass% or more and 2 mass% or less, further preferably 0.2 mass% or more and 1.8 mass% or less.

The above-mentioned liquid paraffin is also called mineral oil and is an oligomer and polymer containing paraffin hydrocarbons. The above-mentioned liquid paraffin includes paraffin oil, naphthenic oil, paraffin/wax, and is a mixture of paraffin hydrocarbons and alkyl naphthenes. Includes liquid paraffin with a specific gravity below 0.8494 at 15°C and liquid paraffin with a specific gravity above 0.8494 at 15°C. In addition, the naphthene content of the liquid paraffin is preferably 15 mass% or more and 55 mass% or less, more preferably 20 mass% or more and 45 mass% or less, and still more preferably 19 mass% based on 100 mass% of the liquid paraffin. % or more and less than 35 mass%.

In this embodiment, the dynamic viscosity (40°C) of the liquid paraffin can be appropriately set according to the purpose of use, but is preferably 3 to 500 mm ² /second, more preferably 5 to 400 mm ² /second, and even more preferably 6 to 6 mm 2 /second. 300mm ² /second, the best is 7 to 150mm ² /second.

In addition, the measurement method of the dynamic viscosity of the above-mentioned liquid paraffin is measured according to the method according to JIS K2283. Specifically, the measurement temperature is 40°C, and an automatic viscometer based on the Ubbelohde viscometer (Viscometer No. 2) is used. (VMC-252 type) (manufactured by Clutch Co., Ltd.).

For example, representative liquid paraffin is not particularly limited, but suitable ones include: CRYSTOL (registered trademark) N352 and PRIMOL (registered trademark) N382 manufactured by ExxonMobil Co., Ltd.; PL-380 manufactured by Sonneborn Co., Ltd.; Idemitsu DIANA Process Oil manufactured by Kosan Co., Ltd. (Registered Trademark) PW-380, PW-150, PW-100, PW-90, DAPHNE Oil (Registered Trademark) CP68N, CP50S; Liquid Paraffin 350-S, PS-350S, LP530-SP manufactured by Sanko Chemical Industry Co., Ltd.; F380N manufactured by Formosa; PARACOS KF-550 and PARACOS KF-350 manufactured by SEOJIN CHEMICAL Corporation; Edelex226 manufactured by Shell Chemical Japan Corporation.

(Antioxidant)

The styrenic resin composition of this embodiment may further contain an antioxidant. In the styrenic resin composition of this embodiment, the antioxidant content is preferably 0.001 to 0.5 mass %, more preferably 0.01 to 0.45 mass %, based on 100 mass % of the total amount of the styrenic resin composition. More preferably, it is 0.03 to 0.4% by mass, and still more preferably 0.05 to 0.35% by mass.

Examples of the antioxidant include phenolic compounds, phosphorus-containing compounds, thioether compounds, and the like.

Examples of the phenolic antioxidant include 2,6-di-tert-butyl p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, (3,5-di-tert-butyl p-cresol, Butyl-4-hydroxybenzyl)distearylphosphonate, 1,6-hexamethylenebis[(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide], 4 ,4'-thiobis(6-tert-butylm-cresol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylene Ethylene bis(4-ethyl-6-tert-butylphenol), 4,4'-butylene bis(6-tert-butyl m-cresol), 2,2'-ethylene bis(4,6 -Di-tert-butylphenol), 2,2'-ethylenebis(4-dibutyl-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) Benzyl)-2,4,6-trimethylbenzene, 2-tert-butyl-4-methyl-6-(2-propenyloxy-3-tert-butyl-5-methylbenzyl) )phenol, 3-(3,5-bis Tributyl-4-hydroxyphenyl)stearyl propionate, tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid methyl ester]methane, thiodiethylenediethylene Alcohol bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,6-hexamethylene bis[(3,5-di-tert-butyl-4-hydroxyphenyl) hydroxy) propionate], bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butyrate] glycol ester, bis[2-tert-butyl-4-terephthalate Methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl] ester, 1,3,5-tris[(3,5-di-tert-butyl-4- Hydroxyphenyl)propyloxyethyl]isocyanurate, 3,9-bis[1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methyl Phenyl)propyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, triethylene glycol bis[(3-tert-butyl-4-hydroxy-5 -methylphenyl)propionate] etc. These can be used individually by 1 type or in mixture of 2 or more types.

Examples of the phosphorus-containing antioxidant include tris(2,4-di-tert-butylphenyl) phosphite, tris(nonylphenyl) phosphite, and tris[2-tert. Butyl-4-(3-tert-butyl-4-hydroxy-5-methylphenylthio)-5-methylphenyl] ester, trialcyl phosphite, octyl phosphite diphenyl Ester, didecyl phosphite monophenyl ester, neopentyl erythritol diphosphite di(tridecyl) ester, neopentyl erythritol diphosphite di(nonylphenyl) ester, neopentyl erythritol Alcohol diphosphite bis(2,4-di-tert-butylphenyl) ester, neopentylerythritol diphosphite bis(2,6-di-tert-butyl-4-methylphenyl) ester, Neopenterythritol diphosphite bis(2,4,6-tri-tert-butylphenyl) ester, neopentylerythritol diphosphite bis(2,4-dicumylphenyl) ester, Isopropylene diphenol diphosphite tetrakis (tridecyl) ester, 4,4'-n-butylene bis (2-tert-butyl-5-methylphenol) diphosphite tetrakis (tridecyl) Alkyl) ester, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane triphosphite hexa(tridecyl) ester, biphenylene bis Tetrakis (2,4-di-tert-butylphenyl) phosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-phosphorous acid Methylene bis(4,6-di-tert-butylphenyl) ester 2-ethylhexyl ester, 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphite Octadecyl ester, fluorophosphorus 2,2'-Ethylene bis(4,6-di-tertiary butylphenyl) acid ester, tris(2-[(2,4,8,10-tetratertiary butyldibenzo[d, f][1,3,2]dioxaphosphepan-6-yl)oxy]ethyl)amine, 2-ethyl-2-butylpropanediol and 2,4,6-tritertiary Butylphenol phosphite, etc. These can be used individually by 1 type or in mixture of 2 or more types.

Examples of the thioether antioxidant include thiodipropionic acid such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate. Dialkyl esters and neopentylerythritol tetrakis(β-alkylmercapto)propionate. These can be used individually by 1 type or in mixture of 2 or more types.

"Additive"

In the present embodiment, at any stage before and after the recovery process when manufacturing each component of the styrene-based resin composition or at the stage of extruding or molding the styrenic-based resin composition, the styrene-based resin composition can be recycled as needed. Add various additives within the scope that hinders the purpose of the present invention, such as ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, various dyes and pigments, inorganic crystal nucleating agents (titanium oxide, tin oxide and other metal oxides), organic crystal nucleating agents, fluorescent whitening agents, light diffusing agents, and specific wavelength absorbers.

It should be noted that the above-mentioned additives in the styrene-based resin composition are preferably 6.0 mass% or less, more preferably 3.5 mass% or less, and still more preferably 0.9 mass%, based on 100 mass% of the styrene-based resin composition. below, more preferably below 0.5% by mass.

The styrene-based resin composition of this embodiment may have rubber-like polymer particles and a styrenic-based polymer, and the total content of the rubber-like polymer particles and the styrenic-based polymer relative to the entire styrene-based resin composition may be Preferably, it accounts for 70 to 100 mass %, More preferably, it accounts for 80 to 98.5 mass %.

The styrene-based resin composition of this embodiment may include rubber-like polymer particles, a styrene-based polymer, and a higher fatty acid compound, and the rubber-like polymer particles, the styrene-based polymer The total content of the compound and the higher fatty acid compound is preferably 70 to 100% by mass, more preferably 80 to 98.5% by mass.

The styrene-based resin composition of the present embodiment may include rubber-like polymer particles, styrene-based polymers, higher fatty acid compounds, and additives. The total content of the polymer, the higher fatty acid compound and the additive may preferably be 70 to 100% by mass, more preferably 80 to 99% by mass.

The styrene-based resin composition of the present embodiment may include rubber-like polymer particles, styrene-based polymers, higher fatty acid compounds, and antioxidants, and the rubber-like polymer particles, styrene-based resin composition may contain The total content of the polymer, the higher fatty acid compound and the antioxidant is preferably 70 to 100% by mass, more preferably 80 to 99% by mass.

The styrene-based resin composition of the present embodiment may include rubber-like polymer particles, styrene-based polymers, higher fatty acid compounds, and plasticizers, and the rubber-like polymer particles, benzene-based resin composition, and The total content of the vinyl polymer, the higher fatty acid compound and the plasticizer is preferably 70 to 100% by mass, more preferably 80 to 99.5% by mass.

The styrene-based resin composition of this embodiment may contain rubber-like polymer particles, styrene-based polymers, higher fatty acid compounds, plasticizers, and antioxidants, and relative to the entire styrene-based resin composition, the rubber-like polymer The total content of the particles, styrenic polymer, higher fatty acid compound, plasticizer and antioxidant is preferably 70 to 100% by mass, more preferably 80 to 99.5% by mass.

(Preferred form of styrenic resin composition)

A preferred form of the styrene-based resin composition of the present embodiment is a styrenic-based resin composition having a sea-island structure containing a rubber-like polymer with an average particle diameter in the range of 0.4 μm to 0.95 μm. Rubber-like polymer particles, and a styrene-based polymer constituting a polymer matrix phase, wherein the styrene-based polymer has: a styrene-based monomer unit (a1), a (meth)acrylate monomer unit (a2) ) 7 to 50 mass% and a (meth)acrylate monomer unit (a3) having a larger molecular weight than the (meth)acrylate monomer unit (a2) 0.001 to 20 mass%, the refractive index of the polymer matrix phase is 1.538 to 1.575, the absolute value of the difference in refractive index between the polymer matrix phase and the rubber-like polymer particles is in the range of 0 to 0.015, and the proportion of components with a molecular weight of 1 million or more in the polymer matrix phase is less than 1% Among all the rubber-like polymer particles contained in the styrenic resin composition, more than 21 volume % of the rubber-like polymer particles have a salami structure, and the number average molecular weight (Mn ) is 40,000 to 120,000, and the weight average molecular weight (Mw) of the styrenic polymer is 100,000 to 300,000, and the MFR of the styrenic resin composition is 1.5 g/10 minutes to 5.0 g/10 minutes. within the range.

This can achieve the effect of simultaneously satisfying sheet productivity and suppressing thickness variation during container molding.

Another preferred form of the styrenic resin composition of the present embodiment is a styrenic resin composition having a sea-island structure. The sea-island structure contains a rubber-like polymer with an average particle diameter in the range of 0.4 μm to 0.95 μm. rubber-like polymer particles, a styrene-based polymer constituting the polymer matrix phase, and a higher fatty acid compound, wherein the aforementioned styrene-based polymer has: styrene-based monomer unit (a1), (meth)acrylate 7 to 50% by mass of the monomer unit (a2) and 0.001 to 20% by mass of the (meth)acrylate monomer unit (a3) having a larger molecular weight than the aforementioned (meth)acrylate monomer unit (a2), the aforementioned styrene The polymer contains a conjugated divinyl monomer unit, and the proportion of the conjugated divinyl monomer unit is relative to the styrene monomer unit (a1) and the (meth)acrylate monomer unit. The total amount of (a2) and the aforementioned (meth)acrylate monomer unit (a3) per mole is less than 2.0×10 ^-6 moles, the refractive index of the aforementioned polymer matrix phase is 1.550 to 1.575, and the aforementioned polymer matrix The absolute value of the difference in refractive index between the phase and the rubber-like polymer particles is in the range of 0.005 or more and 0.015 or less, the proportion of components with a molecular weight of 1 million or more in the polymer matrix phase is less than 1%, and the styrenic resin composition Among all rubber-like polymer particles contained in the substance, more than 21 volume % of the rubber-like polymer particles have a salami structure, and the number average molecular weight (Mn) of the styrenic polymer is 60,000 to 120,000. , and the weight average molecular weight (Mw) of the styrenic polymer is 150,000 to 300,000, and the MFR of the styrenic resin composition is in the range of 1.5 g/10 minutes to 5.0 g/10 minutes.

This not only satisfies sheet productivity and suppresses thickness variation during container molding, but also suppresses damage due to gelation and satisfies predetermined characteristics.

[Physical properties of styrenic resin composition]

<Total transmittance>

In this embodiment, the total light transmittance specified in JIS K 7361-1 of a 0.3 mm thick test piece sheet using the styrenic resin composition of this embodiment as a molding raw material is preferably 84% or more, more preferably It is more than 85%, and even better, it is more than 86%.

<Haze>

In this embodiment, the haze value measured according to JIS K 7105 of a 0.3 mm thick test piece sheet using the styrenic resin composition of this embodiment as a molding raw material is preferably 30% or less, more preferably 27 % or less, and preferably less than 24%.

When the haze value is within the above range, a certain level of transparency can be ensured and the contents of the container can be visually identified.

<Production method of styrenic resin composition>

In the present embodiment, in the method for producing a styrene-based resin composition, the method of blending, melting, kneading, and granulating each raw material component is not particularly limited, and methods commonly used in the production of styrene-based resin compositions can be used. method. For example, the above-mentioned components compounded (mixed) using a drum, Henschel mixer, etc. are melted using a Bambry mixer, a single-screw extruder, a twin-screw extruder, a kneader, etc. The resin composition can be obtained by kneading and granulating using a rotary cutter, fan cutter, or the like. The resin temperature during melting and kneading is preferably 180°C to 240°C. In order to achieve the target resin temperature, the barrel temperature of the extruder, etc. is preferably set to a temperature 10°C to 20°C lower than the resin temperature. When the resin temperature is less than 180°C, mixing is insufficient and unsatisfactory. On the other hand, when the resin temperature exceeds 240° C., thermal decomposition of the resin occurs, which is undesirable.

[molded body]

The molded article of this embodiment can be obtained by molding the above-described styrene-based resin composition. The molded body is not particularly limited as long as it is obtained by molding the above-mentioned resin composition, but it is preferably an extrusion molded body or a sheet body (including a film). An example of a secondary molded article obtained by using the extrusion-molded sheet of the present embodiment includes a packaging container for electronic components such as a carrier tape. The container can be directly processed at the extruder outlet. It can be manufactured by shaping (shaping), or it can be manufactured by further shaping the obtained sheet using an extruder. In addition, the sheet of this embodiment can be used not only for packaging containers for electronic components but also for manufacturing (molding) molded objects including other containers.

The sheet of this embodiment is a non-foamed or foamed sheet. In addition, the sheet of this embodiment can be used as a multi-layer with a styrene-based resin such as polystyrene resin, and in addition to or instead of the styrene-based resin or the like layer, It can also be laminated with resins other than the styrene-based resin and used. Examples of resins other than styrene-based resins include PC resin, ABS resin, PP resin, PP/PS-based resin, PET resin, nylon resin, and the like.

Hereinafter, a sheet as a preferred molded article using the styrene-based resin composition of this embodiment will be described.

"Method for manufacturing sheet of styrenic resin composition"

The sheet body of this embodiment contains the above-described styrene-based resin composition. Furthermore, the sheet body of this embodiment can be formed into a molded article by the above-mentioned melt-kneading molding machine, or by injection molding or injection compression molding using the obtained pellets of the styrene-based resin composition as raw materials. , extrusion molding, blow molding, pressure molding, vacuum molding, foam molding, etc. to manufacture molded products.

<Extruded sheet>

This embodiment provides an extruded sheet formed using the styrenic resin composition of the present invention. The extruded sheet may be either non-foamed or foamed. As a manufacturing method of the extruded sheet, a generally known method can be used. As a method of manufacturing a non-foamed extruded sheet, a device that takes up the sheet (the device uses a single-screw or twin-screw extruder equipped with a T-die head, a uniaxial stretching machine or a twin-screw extruder) can be used. A method using an extrusion foaming molding machine (equipped with a T-shaped die or a circular die), etc. can be used as a method of manufacturing a foamed extruded sheet.

-Foam extruded sheet-

In this embodiment, when forming a foamed extruded sheet, generally used substances can be used as the foaming agent and foaming nucleating agent during extrusion foaming. As the foaming agent, butane, pentane, chlorofluorocarbon (freon), carbon dioxide, water, etc. can be used, butane is preferred. In addition, as a foaming nucleating agent, talc or the like can be used.

In this embodiment, the thickness of the foamed extruded sheet is preferably 0.5mm to 5.0mm, the apparent density is preferably 50g/L to 300g/L, and the mass per unit area is preferably 80g/m ² to 300g /m ² . The foamed extruded sheet of the present invention can also be laminated by, for example, further laminating films. The type of membrane used is generally a polystyrene membrane.

-Non-foam extruded sheet-

In the present embodiment, the thickness of the non-foamed sheet is, for example, about 0.1 to 1.0 mm, which is preferable from the viewpoints of rigidity and thermoforming cycle. In addition, the uniaxial sheet can be formed by using only ordinary low-magnification roller stretching. The biaxial stretched sheet is stretched by a roller from about 1.3 times to about 7 times in the direction of travel (MD), and then a tenter is used to stretch the sheet. The extension in the vertical direction (TD) is about 1.3 times to about 7 times, which is preferable in terms of strength. In addition, the non-foamed sheet may be laminated with a styrene-based resin such as polystyrene resin other than the styrene-based resin composition and used. It can also be laminated with resins other than styrene-based resins and used. Examples of resins other than the styrene-based resin include PET resin, nylon resin, and the like.

<Biaxially stretched sheet>

Another form of the sheet of this embodiment is a biaxially stretched sheet formed using the above-mentioned styrenic resin composition. As a manufacturing method of a biaxially stretched sheet, a generally known method can be used. Biaxially stretched sheets can be stretched in the direction of travel (MD) with rollers and then vertically stretched with a tenter. It can be produced by stretching in the direction (TD), or by heating the styrenic resin composition molded into a plate shape to the Fica softening temperature of the composition + about 10°C to 40°C using a tenter, or Made with simultaneous biaxial extension.

The stretching ratio of the biaxially stretched sheet of this embodiment is about 1.3 to 7.0 times in the MD direction and about 1.3 to 7.0 times in the TD direction, which are good from the viewpoint of strength.

In order to ensure the strength, especially the rigidity, of the sheet and the container, the average thickness of the biaxially stretched sheet of this embodiment is preferably 0.1 mm or more, more preferably 0.15 mm or more, and still more preferably 0.2 mm or more. On the other hand, from an economical viewpoint, the thickness is preferably 0.7 mm or less, more preferably 0.6 mm or less, and still more preferably 0.5 mm or less.

The orientation relaxation stress in the longitudinal and transverse directions of the biaxially stretched sheet of this embodiment is preferably in the range of 0.4 to 1.3 MPa. By adjusting the orientation relaxation stress within this range, the strength of the molded product of the biaxially stretched sheet can be maintained.

When the biaxially stretched sheet of the present embodiment is used as a food packaging container, in order to prevent fogging caused by moisture evaporated from the food, a known anti-fogging agent may be coated on at least one side of the biaxially stretched sheet. superior. Examples of the anti-fog agent include nonionic surfactants such as sucrose fatty acid ester and polyglycerol fatty acid ester, polyether-modified silicone oil, and the like.

The method of applying the anti-fog agent to the biaxially stretched sheet of the present embodiment is not particularly limited. Briefly, coating using a roll coater, a blade coater, a gravure roll coater, etc. Methods. In addition, spraying, dipping, etc. can also be used. In addition, surface treatment by corona treatment, ozone treatment, primer treatment, etc. can also be performed before coating to improve the wettability of the surface of the biaxially stretched sheet before coating.

[Secondary molded products]

Another aspect of this embodiment is to provide a secondary molded product formed using the above extruded sheet, particularly a food container or a carrier tape for transporting electronic parts. The sheet body of this embodiment can be used to produce, for example, food containers (for example, lid materials for lunch boxes or containers for holding dishes formed by vacuum forming), carrier tapes for transporting electronic parts, and the like.

In addition, in this embodiment, the manufacturing method of the container molded from a sheet body is not specifically limited, For example, compressed air molding and vacuum molding are mentioned.

Hereinafter, as an example of a container molded from the styrene-based resin composition of this embodiment, a food container, a carrier tape for transporting electronic components, and a packaging material will be described.

<Food Container>

The food container of the present invention is formed from the above-mentioned styrene-based resin composition or sheet body. Hereinafter, preferred forms of the food container of the present invention will be described using Figures 1 and 2 .

Fig. 1 shows an example of the food container 1 according to the present invention. Fig. 1 is a perspective view showing the food container body 2 that mainly contains pasta or rice-don type foods and the lid portion 3 covering the opening 6 of the food container body 2 . In addition, in FIG. 1, for convenience of description, as an example of the food container 1 of this embodiment, the food container main body 2 and the lid part 3 which can be fitted with the opening part 6 of this food container main body 2 are shown. However, this embodiment The food container 1 of this type may also have only the food container body 2 . In addition, Fig. 2 is a schematic diagram showing a cross-section of the mold 9 for manufacturing the food container 1 (especially the food container body 2) of Fig. 1.

Next, the shape of the food container 1 of this embodiment and its formation method are demonstrated using FIG. 1. FIG.

The food container body 2 of this embodiment has a recess 4 capable of containing food. 1 shows a food container 1 having one recess 4 as an example of the recess 4. In order to visually confirm the amount of the contents from the outside, a recess is formed on the inner wall of the food container body 2 over the entire circumference. slot 5. Furthermore, the area of the bottom portion 7 of the food container body 2 is smaller than the area of the opening 6 . In addition, the opening 6 of the food container body 2 is provided with an outwardly protruding edge portion 8, and the lid portion 3 covering the opening 6 of the food container body 2 can be fitted with the edge portion 8.

The shape of the recessed portion 4 is not particularly limited, and examples thereof include a (roughly) cylindrical shape, a polygonal cylindrical shape, and the like.

Furthermore, the food container of this embodiment may have a plurality of recessed portions 4 . An example of a food container having a plurality of recessed portions 4 is a shape in which a plurality of food items, that is, dishes, are divided by partitions like a food container used in a commercially available lunch box.

The food container 1 of this embodiment can be manufactured using the mold 9 shown in FIG. 2, for example. As an example of this embodiment, a mode in which the food container 1 (food container body 2) is integrally molded from a sheet body 10 formed of a styrene-based resin composition will be described below using FIG. 2 .

For example, the sheet body 10 having a thickness of 100 to 1000 μm is produced by extrusion molding a styrene-based resin composition. At this time, the surface layer of the sheet body 10 may be coextruded with polystyrene or polypropylene or film laminated to a thickness of 1 to 100 μm. Then, the obtained sheet body 10 is preheated at 150°C to 250°C for 5 to 60 seconds, and then the heated sheet body 10 is disposed to cover the recess 11 of the mold 9 and is shaped by a predetermined forming method. shape. For example, by applying a vacuum to the recessed portion 11, the food container body 2 can be shaped into a desired shape.

Furthermore, the sheet body 10 may be disposed so as to cover the recessed portion 11 of the mold 9, and then heated and performed by a predetermined molding method (for example, hot press molding, vacuum molding, compressed air molding, plunger-assisted molding). Give shape.

As a preferred example of this embodiment, the food container 1 (especially the food container body 2 ) can be formed by using the mold 9 to perform hot press forming, vacuum forming, compressed air forming or columnar molding on the heated sheet body 10 . The plug assists in forming and gives shape.

Furthermore, when manufacturing food containers 1 (especially the food container body 2) with different depths, the depth d of the recessed portion relative to the diameter of the upper surface of the recessed portion (= the diameter of the opening) can be changed by the spacer 12 )r ratio (d/r). As an example, FIG. 2 shows a state in which a spacer 12 is provided in the recessed portion 11 of a depth d to form a depth d2 or a depth d1.

The average thickness (wall thickness) of the food container 1 used in the present invention is 0.05 to 3 mm, preferably 0.1 to 2 mm, and more preferably 0.15 to 1.5 mm. When it is thinner than 0.05mm, the rigidity of the container is insufficient. When it is thicker than 3mm, the container becomes heavy, the material cost becomes high, and the volume increases, making it difficult to discard as garbage.

In this embodiment, the ratio of the depth of the food container/the diameter of the opening (drawing ratio) is preferably 0.1 or more and 1.0 or less. When the deep drawing ratio is greater than 1.0, thickness deviation will occur and the strength of the container will decrease. In addition, when the depth/diameter ratio is less than 0.1, the shape of the container becomes flat, so thickness deviation is unlikely to occur, and oil or oil-containing liquid remains on the bottom of the food container (especially the outer peripheral portion of the bottom). This makes it difficult to achieve the effect of oil resistance. On the other hand, if the deep drawing ratio (ratio of depth/diameter) is 0.1 or more and 1.0 or less, it is not only relatively easy to accommodate contents such as food, but also it is easy to exert the effect of oil resistance regardless of the food items that can be accommodated.

The diameter of the opening in this specification means the diameter when the shape of the opening is a circle, the minor diameter when the shape of the opening is an elliptical circle, and the diameter of the diagonal when the shape of the opening is a polygon. Minimum length.

Furthermore, in order to maintain the airtightness of the container, it is preferable to provide an uneven shape on the upper part of the container and design it to improve the fitability. Since the food container used in the present invention has good shape retention against heat, it is a food container with excellent fitability.

The food container molding method according to the present invention uses injection molding, injection compression molding, extrusion molding, blow molding, pressure molding, hot press molding, vacuum molding, compressed air molding, and plunger-assisted molding. and foam molding methods, etc., but the molding method is not limited. In the food container used in the present invention, in particular from the viewpoint of productivity and cost, a method of forming the sheet (film) by vacuum forming is preferred.

The food container according to the present invention is preferably formed from a styrenic resin composition sheet, and more preferably, the styrenic resin composition sheet composed of the aforementioned styrenic resin composition is formed and then shaped.

The thickness of the sheet body used in this embodiment is preferably 0.1 to 2 mm, more preferably 0.2 to 1 mm, and even more preferably 0.3 to 0.8 mm. When it is thinner than 0.1 mm, the rigidity is insufficient when it is made into a container. When it is thicker than 2 mm, the heating time for vacuum forming becomes long and the productivity decreases.

<Carrier tapes and packaging materials for shipping electronic components>

One form of the container using the styrene-based resin composition for containers of the present embodiment is a carrier tape for transporting electronic components composed of a base material having plural structures for accommodating electronic components. A recessed portion and an edge portion capable of being bonded to a covering sealing the recessed portion, wherein the base material contains a styrenic resin composition for containers.

An example of the carrier tape for transporting electronic components and the packaging material for transporting electronic components according to this embodiment will be described below using FIGS. 3 and 4 . Fig. 3 is a perspective view showing a form of storing electronic components using a carrier tape for transporting electronic components. The carrier tape for transporting electronic components is composed of a carrier tape body 21 . In addition, as shown in FIG. 4 to be described later, the packaging material for transporting electronic components is composed of a carrier tape body 21 and a cover tape 27 .

In FIG. 3 , the carrier tape body 21 is formed on a long sheet body with a plurality of recessed portions 22 capable of accommodating electronic components 25 at predetermined intervals. In addition, an edge portion 23 capable of being adhered to a cover tape (not shown in the third figure) serving as a cover for sealing the recessed portions 22 is formed as a remainder around the recessed portions 22 formed at predetermined intervals. Furthermore, as shown in FIG. 3 , electronic components 25 are accommodated inside the recessed portions 22 arranged at predetermined intervals. In addition, in Figure 3, as a preferred form of the carrier tape body 21, a through hole 24 is provided. More specifically, a plurality of through holes 24 are provided in the edge portion 23 at predetermined intervals so that one through hole 24 corresponds to one recessed portion 22 . The through hole 24 functions as a sprocket, and is therefore also called a sprocket hole, and is used for transporting the carrier tape.

Next, Fig. 4 is a perspective view showing the process of storing and sealing electronic components using packaging materials for transporting electronic components. As shown in FIG. 4 , the manufactured electronic component 25 is accommodated in the recess 22 of the carrier tape body 21 , covered with a cover tape 27 , and the cover tape 27 is heated and welded (heat-sealed) at the edge 23 to form a track. The sealing portion 26 is formed in a shape to fix the cover tape 27 to the carrier tape body 21 to seal the recessed portion 22 . Then, the packaged packaging material containing the electronic components 25 is sequentially wound around a reel, and is stored and transported in a roll shape. In addition, in Figure 4, as the carrier tape The preferred form of body 21 is provided with through holes 24. More specifically, a plurality of through holes 24 are provided in the edge portion 23 at predetermined intervals so that one through hole 24 corresponds to one recessed portion 22 . The through hole 24 functions as a sprocket, and is therefore also called a sprocket hole, and is used for transporting the carrier tape.

As described above, when the electronic components 25 packaged with the cover tape 27 and the carrier tape body 21 are mounted on the substrate, the packaging material that has been rolled into a roll containing the electronic components 25 is pulled out, and the above-mentioned storage and sealing steps are performed. On the contrary, the electronic components 25 are taken out for installation while peeling off the cover tape 27 from the carrier tape body 21 .

Typically, a transparent plastic sheet is used as the carrier tape body 21 and the cover tape 27 so that the electronic components 25 inside can be visually confirmed after packaging. In addition, as the carrier tape body 21, a material obtained by cutting a sheet body (so-called resin sheet) into a strip shape and forming the recessed portion 22 by embossing is used. Therefore, the resin sheet used for molding the carrier tape body 21 is required to have good formability that suppresses opening of holes during embossing molding, is not easily thinned, and has mechanical strength to protect the electronic components 25 after packaging.

However, for electronic components, not only the miniaturization of various components but also the enlargement due to the integration (modularization) of multiple components are advancing. Therefore, there are increasing demands on the deep drawing formability of carrier tapes.

Therefore, the present invention can suppress and prevent thinning during molding by using the styrene-based resin composition for containers of the present embodiment in the carrier tape body 21 and can exhibit excellent deep drawing formability during molding. Therefore, We can provide carrier tapes for transporting electronic parts that are suitable for large parts.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above examples and may be appropriately modified.

Example

Hereinafter, the present invention will be specifically described through examples and comparative examples, but the present invention should not be construed as being limited to these examples. In addition, the analysis and evaluation methods of the resin compositions in Examples and Comparative Examples are as described above.

(1) Method for measuring the contents of styrene-based monomer unit (a1), (meth)acrylate monomer unit (a2), and (meth)acrylate monomer unit (a3)

Content (mass %) of styrenic monomer unit (a1), (meth)acrylate monomer unit (a2), and (meth)acrylate monomer unit (a3) in the styrenic resin composition for containers ) The resin composition is quantified from the spectral integral ratio measured using a proton nuclear magnetic resonance ( ¹ H-NMR) device.

Sample preparation: Dissolve 30 mg of the resin composition in 0.75 mL of d6-DMSO by heating at 60°C for 4 to 6 hours.

Measuring machine: JNM ECA-500 manufactured by JEOL Ltd.

Measurement conditions: measurement temperature 25°C, observation core ¹ H, accumulation times 64 times, repetition time 11 seconds.

(2) Measurement of the content of conjugated diene monomer units in the styrenic resin composition for containers

The content (mass %) of the conjugated diene monomer units derived from the rubber-like polymer in the styrene-based resin composition for containers was measured as follows. Accurately weigh 0.4 g of the styrene resin composition for containers in a volumetric flask (let this mass be W), add 75 mL of chloroform to fully disperse, and then add 18 g of iodine monochloride dissolved in 1000 mL of carbon tetrachloride. The resulting solution was 20 mL, and was stored in a cool and dark place. After 8 hours, chloroform was added and the mark was aligned. Take 25 mL of this solution, add 60 mL of a solution of 10 g of potassium iodide dissolved in a mixture of 800 mL of water and 200 mL of ethanol, and use a solution of 10 g of sodium thiosulfate dissolved in 1000 mL of water (the molar concentration of this solution is set to x) Perform titration. Assuming AmL for this test and BmL for the blank test, the conjugated diene monomer unit (mass %) derived from the rubber-like polymer is determined by the following formula.

Conjugated diene monomer unit derived from rubber-like polymer (butadiene amount) = 10.8×x×(B-A)/W

(3) Determination of molecular weight

The number average molecular weight, weight average molecular weight, Z-weight average molecular weight, and high molecular weight of 800,000 or more of the styrenic polymer or polymer matrix phase were calculated using gel permeation chromatography (GPC) and measured under the following conditions.

Device: HLC-8220 manufactured by Tosoh Corporation

Separation column: TSK gel Super HZM-H (inner diameter 4.6mm) manufactured by Tosoh Corporation, two columns connected in series

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

Determination solvent: tetrahydrofuran (THF)

Sample preparation: Dissolve 5 mg of measurement sample in 10 mL of solvent, and filter with a 0.45 μm filter.

Injection volume: 10μL

Measuring temperature: 40℃

Flow rate: 0.35mL/minute

Detector: UV-visible light detector (UV-8020)

To prepare the calibration curve, 11 types of TSK standard polystyrene manufactured by Tosoh Corporation (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F- 4. F-2, F-1, A-5000). Calibration curves were prepared using a linear approximation.

(4) Measurement of refractive index

The refractive index of the polymer matrix phase and rubber-like polymer particles was measured as follows: The polymer matrix phase and rubber-like polymer particles were measured according to the following paragraph "(5) Toluene-insoluble component content and swelling index measurement" The separation was carried out using the same procedure as described in , and the solvent toluene was dried, and then measured using an Abbe refractometer at 25°C. In addition, the absolute value of the difference in refractive index between the polymer matrix phase and the rubber-like polymer particles was calculated as the absolute value of the difference between the two measured values.

(5) Determination of toluene-insoluble content and swelling index

The toluene-insoluble content (mass %) and swelling index in the styrenic resin composition for containers were measured as follows. Accurately weigh 1.00 g of the rubber-modified styrenic resin composition in a sedimentation tube (let this mass be W1), add 20 mL of toluene, shake at 23°C for 2 hours, and use a centrifuge (manufactured by Sakuma Seisakusho Co., Ltd., SS- 2050A rotor: 6B-N6L) centrifuge for 60 minutes at a temperature of 4°C, a rotation speed of 20,000 rpm, and a centrifugal acceleration of 45,100×G. Slowly tilt the sedimentation tube about 45 degrees and decant to remove the supernatant. Accurately weigh the mass of toluene-containing insoluble components (let this mass be W2), vacuum dry for 1 hour at 160°C and 3 kPa or less, cool to room temperature in a desiccator, and accurately weigh the mass of toluene-insoluble components. (Set this mass to W3).

The content and swelling index of the toluene-insoluble components in the rubber-modified styrene-based resin composition, that is, the content and swelling index of the rubber-like polymer particles in the styrene-based resin composition for containers were determined by the following formula.

Content of toluene-insoluble components = W3/W1×100

Swelling index of toluene-insoluble components = W2/W3

(6) Measurement of the average particle size of rubber-like polymer particles

The average particle diameter (μm) of rubber-like polymer particles is measured by taking transmission electron microscope photographs using ultrathin sectioning in 10 fields of view, and measuring the particle diameter of 1,000 particles in all the photographs. The following method is used: Find the formula.

Average particle size=Σni‧Di ⁴ /Σni‧Di ³

(In the formula, ni is the number of rubber-like polymer particles having a particle diameter Di. In addition, Di is the average value of the major axis and the minor axis of the rubber-like polymer particles.)

(7)Reduced viscosity

The reduced viscosity of the styrenic resin composition in this example was measured in a toluene solution at 30° C. and a concentration of 0.5 g/dL.

(8) Determination of melt mass flow rate (MFR)

The melt mass flow rate (MFR) (g/10 minutes) of the styrenic resin composition was measured in accordance with JIS K7210 (200°C, load 49N).

(9)Measurement of melt tension

The melt tension (g) of the styrenic resin composition was measured according to the following conditions.

Device name: Capillary rheometer RH10 (manufactured by Malvern)

Measuring temperature: 190℃

Extrusion speed: 20mm/min

Collection (pull) speed: 3.1m/minute

Drying conditions: The styrenic resin composition was dried at 80° C. for 3 hours before measurement.

Barrel diameter: 15mm

Capillary die length: L=16mm

Capillary die diameter: D=1mm (L/D=16)

Under the above measurement conditions, the range in which the load is stable is averaged and used as the melt tension value. It cannot be measured when the wire material is cut during traction or when the load variation coefficient is greater than 10%.

(10) Fika softening temperature

According to JIS K7206, the Fica softening temperature (° C.) of the styrene-based resin composition for containers obtained in the following Examples and Comparative Examples was measured. The load was set to 49N, and the heating rate was set to 50°C/hour.

(11)DuPont impact strength

片材擠出機(創研株式會社製造)將容器用苯乙烯系樹脂組成物擠出，製作成0.3mm厚的片材。對於所得到的片材，使用直徑12.5mm的投射器(missile)、直徑16.5mm的托盤、0.2kg的砝碼並根據JIS K5600-5-3進行測定。 Use 30mm

A sheet extruder (manufactured by Soken Co., Ltd.) extruded the styrene-based resin composition for containers into a 0.3 mm thick sheet. The obtained sheet was measured in accordance with JIS K5600-5-3 using a missile with a diameter of 12.5 mm, a tray with a diameter of 16.5 mm, and a weight of 0.2 kg.

(12) Determination of total light transmittance and haze

片材擠出機(創研株式會社製造)，將在實施例和比較例中製作的容器用苯乙烯系樹脂組成物按照以下條件擠出，製作成0.3mm厚的片材。對於所得到的片材，根據JIS K7361-1測定總透光率(%)。此外，根據JIS K7136測定霧度(%)。 Use 30mm

A sheet extruder (manufactured by Soken Co., Ltd.) was used to extrude the styrene-based resin composition for containers produced in Examples and Comparative Examples under the following conditions to produce a 0.3 mm thick sheet. The total light transmittance (%) of the obtained sheet was measured based on JIS K7361-1. In addition, the haze (%) was measured based on JIS K7136.

<Extrusion conditions>

When using a styrenic resin composition, the setting temperature of the resin melting zone of the extruder: 200 to 230°C, the T-die temperature setting: 230°C, the roller temperature setting: 60°C to 80°C, so that the discharge volume is: 6kg/ hour to produce a sheet of 0.3±0.02mm.

(13) Evaluation of sheet thickness variation

As an indicator of thinning during molding, the thickness variation of the sheet was evaluated according to the following procedure. In addition, the thickness of the sheet itself was measured to confirm whether thinning occurred during molding.

片材擠出機(創研株式會社製造)，將在實施例和比較例中得到的苯乙烯系樹脂組成物擠出，製作成0.3mm厚的片材。從得到的片材中切出縱230mm×橫230mm大小的試驗片，使用創研株式會社製造的片材容器成形機，用該片材成形機的固定框夾住試驗片，將加熱器的平均溫度設定為樹脂組成物的菲卡軟化溫度+115℃、環境溫度設定為130℃，加熱20秒。接著，使其在開口部的直徑8cm、底面部的直徑4cm、深度10cm的杯狀模具上連同固定框一起滑動而進行真空成形，每次成形20個成形體。對於從該成形體的口部起8cm位置的側面厚度相對於從該口部起2cm位置的側面厚度的比例，取20個成形體的測定值進行平均，作為片材的厚度偏差性，按照以下標準進行評價。 Use 30mm

A sheet extruder (manufactured by Soken Co., Ltd.) was used to extrude the styrene-based resin composition obtained in the examples and comparative examples into a 0.3 mm thick sheet. A test piece with a size of 230 mm in length and 230 mm in width was cut out from the obtained sheet, and a sheet container forming machine manufactured by Soken Co., Ltd. was used. The test piece was clamped with the fixed frame of the sheet forming machine, and the average value of the heater was The temperature was set to the Fica softening temperature of the resin composition + 115°C, the ambient temperature was set to 130°C, and the heating was performed for 20 seconds. Next, the mold was slid together with a fixed frame on a cup-shaped mold having an opening diameter of 8 cm, a bottom surface diameter of 4 cm, and a depth of 10 cm to perform vacuum molding, and 20 molded bodies were molded at a time. The ratio of the side thickness at a position 8 cm from the mouth of the molded body to the side thickness at a position 2 cm from the mouth was averaged from the measured values of 20 molded bodies. The thickness variation of the sheet was as follows: standards for evaluation.

◎: 0.75 or above;

○: 0.6 or more and less than 0.75;

△: 0.5 or more and less than 0.6;

×: less than 0.5;

□: The thickness of the side surface at a position 2 cm from the mouth is 0.15 mm thinner (equivalent to half the thickness of the sheet) than the sheet of Example 1, and the thinning during molding occurs significantly;

Damaged: The container is damaged and cannot be evaluated.

(14) Evaluation of deep drawing formability of sheets

片材擠出機(創研株式會社製造)，將實施例和比較例中得到的苯乙烯系樹脂組成物擠出，製作成0.3mm厚的片材。從得到的片材中切出縱250mm×橫250mm大小的試驗片，使用創研株式會社製造的片材容器成形機，用該片材成形機的固定框夾住試驗片，將加熱器的平均溫度設定為樹脂組成物的菲卡軟化溫度+115℃、環境溫度設定為130℃，加熱20秒。接著，使其在開口部的直徑8cm、底面部的直徑4cm、深度10cm的杯狀模具上連同固定框一起滑動而進行真空成形，每次成形20個成形體。 Use 30mm

A sheet extruder (manufactured by Soken Co., Ltd.) was used to extrude the styrene-based resin composition obtained in the Examples and Comparative Examples to produce a 0.3 mm thick sheet. A test piece with a size of 250 mm in length and 250 mm in width was cut out from the obtained sheet, and a sheet container forming machine manufactured by Soken Co., Ltd. was used. The test piece was clamped with the fixed frame of the sheet forming machine, and the average value of the heater was The temperature was set to the Fica softening temperature of the resin composition + 115°C, the ambient temperature was set to 130°C, and the heating was performed for 20 seconds. Next, the mold was slid together with a fixed frame on a cup-shaped mold having an opening diameter of 8 cm, a bottom surface diameter of 4 cm, and a depth of 10 cm to perform vacuum molding, and 20 molded bodies were molded at a time.

It was visually confirmed whether the bottom corner portion of the obtained molded body conformed to the shape of the mold and whether it was extremely thin-walled.

The number of molded bodies whose bottom corner portions conform to the shape of the mold and can be formed without becoming extremely thin is used as an index of deep drawing formability.

◎: 18 or more;

○: More than 15 and less than 18;

△: More than 12 and less than 15;

×: less than 12;

Damaged: The container is damaged and cannot be evaluated.

"raw materials"

In the Examples and Comparative Examples, the following materials were used.

〈Monovinyl compound〉

Styrene: Styrene monomer [manufactured by Asahi Kasei Co., Ltd.]

〈(meth)acrylate〉

Methyl methacrylate: manufactured by Asahi Kasei Co., Ltd.

Butyl acrylate: manufactured by Wako Pure Chemical Industries, Ltd.

〈Rubber-like polymer〉

Styrene-butadiene rubber: [Manufactured by Asahi Kasei Co., Ltd.: ASAPRENE (registered trademark) 625A]

<other>

Polymerization initiator 1: 1,1-bis(tert-butylperoxy)cyclohexane [manufactured by NOF Corporation: PERHEXA C]

Chain transfer agent 2: α-methylstyrene dimer [manufactured by NOF Corporation: H-dimer]

Ethylbenzene: [manufactured by Wako Pure Chemical Industries, Ltd.]

Higher fatty acid compound: Stearic acid [manufactured by Dainichi Chemical Industry Co., Ltd.: DAIWAX STF]

Antioxidant: 3-(3,5-di-tert-butyl-4-hydroxyphenyl)octadecylpropionate [manufactured by BASF Japan: IRGANOX 1076]

Plasticizer: Liquid paraffin [manufactured by Samko Chemical Industry Co., Ltd.: PS-350S]

"Example 1"

Preparation of styrenic resin composition (A-1)

Production was performed using a polymerization device obtained by connecting two reactors equipped with a stirrer in series and arranging an extruder with a vacuum exhaust port. Specifically, a B-S type (B: butadiene block, S: styrene block) as a rubbery polymer was prepared from 56.4 parts by mass of styrene, 21.1 parts by mass of methyl methacrylate, and 3.7 parts by mass of butyl acrylate. section) and a styrene content of 38 mass % of a rubbery polymer, 8.7 parts by mass, 10 parts by mass of ethylbenzene, 0.02 parts by mass of 1,1-bis(tert-butylperoxy)cyclohexane, α-methyl Styrene dimer 0.17 parts by mass and antioxidant 0.134 parts by mass The raw material solution composed of parts is supplied to the reactor for polymerization. The raw material solution prepared above was continuously supplied to a 6.2L laminar flow reactor-1 equipped with a stirrer and capable of temperature control in three zones at a rate of 3.2L/hour, and the temperature was adjusted to 122°C/127°C/132°C. The mixer speed is set to 150 rpm. Next, the reaction liquid was fed to a 6.2L laminar flow reactor-2 equipped with a stirrer and capable of temperature control in three zones, connected in series to the laminar flow reactor-1. The temperature is set to 125℃/130℃/135℃. Next, the reaction liquid was fed to the 6.2L laminar flow reactor-3 connected in series to the laminar flow reactor-2 and equipped with a stirrer and capable of controlling the temperature in three zones. The temperature is set to 130℃/135℃/140℃. Then, the reaction liquid from the laminar flow reactor-3 is supplied to a two-stage extruder with a vacuum exhaust port that has been adjusted to 210 to 230°C and 1.5 to 2.0 kPa to remove volatilization of unreacted monomers and solvents. The resin extruded into strand form is cut to obtain granular styrenic resin (1).

The solid content concentration of the obtained styrenic resin (1) was determined by the formula [(sample mass after drying/sample before drying) after drying the polymerization liquid under reduced pressure of 215° C. and 2.5 kPa for 30 minutes. Mass) × 100%] measured.

Then, 100 parts by mass of the obtained styrene-based resin (1) and 0.15 parts by mass of stearic acid were blended and granulated using a single-screw extruder to prepare a styrene-based resin composition for containers (A-1 ).

The physical properties of the obtained styrene-based resin composition (A-1) for containers are shown in Table 1. In addition, the reduced viscosity of the styrenic resin composition (A-1) prepared in Example 1 was in the range of 0.50 to 0.85 dL/g.

"Examples 2 to 16"

Except changing the conditions and the additive formula as shown in Table 1, the same operation as in Example 1 was performed to obtain styrenic resin compositions (A-2) to (A-16). Styrene of Examples 2 to 16 Table 1 shows the physical properties and evaluation results of the vinyl resin compositions (A-2) to (A-16). In addition, the reduced viscosity of the rubber-like polymer particles in the styrenic resin compositions (A-2) to (A-16) prepared in Examples 2 to 16 is 0.50 to 0.85 dL/g. within the range.

"Comparative Examples 1 to 6"

In Comparative Examples 1 to 6, the same operation as in Example 1 was performed except that the conditions were changed as shown in Table 1, and styrenic resin compositions (1) to (6) were obtained. Table 1 shows the physical properties and evaluation results of the styrenic resin compositions (1) to (6) of Comparative Examples 1 to 6.

[Table 1]

[Table 2]

From the experimental results in Table 1 above, it was clearly confirmed that the styrenic resin compositions (A-1) to (A-16) of Examples 1 to 16 all obtained transparency while maintaining a certain level (haze value 30% or less). ), a styrenic resin composition that suppresses and prevents thinning during molding and has excellent deep drawing formability during molding. However, the styrenic resin composition (A-6) of Example 6 was discolored to yellow due to the thermal history during sheet forming and thickness variation evaluation, compared with other Examples. From the experimental results of Example 6 and other Examples, it is considered that the antioxidant was not added. impact on life. In addition, the reason why the evaluation result of deep drawing formability of Example 11 is worse than that of other Examples is considered to be because there are less high molecular weight components of 800,000 or more.

Since stearic acid, which is a higher fatty acid compound, was not added in Example 12, the thickness variation and deep drawing properties were slightly poor. In Example 13, the DuPont impact strength was low because the rubber particle size was small. In Example 14, the DuPont impact strength was slightly poor because the proportion of salami structures in the rubber-like polymer particles was low. Since Example 15 had a large rubber particle size, the transparency was worse than that of other Examples. In Example 16, since the content of the conjugated diene monomer unit was low, the DuPont impact strength was slightly deteriorated.

On the other hand, the evaluation results of Comparative Examples 1 to 6 are estimated as follows.

Comparative Example 1 had a small content of methyl methacrylate, so the haze value was high and the transparency was poor. In addition, Comparative Example 2 resulted in poor extrusion productivity due to a low melt mass flow rate. Next, in Comparative Example 4, since the content of butyl acrylate is high, the melt mass flow rate becomes high, the heat resistance becomes low, and the side walls during container molding become significantly thinner. Comparative Example 5 had poor extrusion productivity due to a low melt mass flow rate, and the container was damaged during the evaluation of thickness variation and deep drawing properties. A gelatinous substance was observed near the break. In Comparative Example 6, since the melt mass flow rate was high and stearic acid, which is a higher fatty acid compound, was not added, thickness variation and deep drawability were poor.

Claims (11)

A styrenic resin composition containing: rubbery polymer particles containing a rubbery polymer, and Styrenic polymers constituting the polymer matrix phase; wherein, The aforementioned styrene-based polymer has: a styrene-based monomer unit (a1) and a (meth)acrylate monomer unit (a2) of 7 to 50% by mass. (meth)acrylate monomer unit (a3) with large molecular weight: 0.001 to 20% by mass, The refractive index of the aforementioned polymer matrix phase is 1.538 to 1.575, and the absolute value of the difference in refractive index between the aforementioned polymer matrix phase and the aforementioned rubber-like polymer particles is in the range of 0 to 0.015, The number average molecular weight Mn of the styrenic polymer is 40,000 to 120,000, and the weight average molecular weight Mw of the styrenic polymer is 100,000 to 300,000, The MFR of the styrenic resin composition is in the range of 1.5 g/10 minutes to 5.0 g/10 minutes. The styrenic resin composition according to claim 1, wherein the proportion of high molecular weight components of 1 million or more in the molecular weight of the polymer matrix phase is less than 1% relative to the entire styrenic polymer. The styrene-based resin composition according to claim 1 or 2, wherein among all the rubber-like polymer particles contained in the styrene-based resin composition, 21% by volume or more of the rubber-like polymer particles have Salami structure. The styrenic resin composition according to claim 1 or 2, wherein the (meth)acrylate monomer unit (a2) is a methyl (meth)acrylate monomer unit, and the (meth)acrylic acid The ester monomer unit (a3) is a butyl (meth)acrylate monomer unit. The styrenic resin composition according to claim 1 or 2, wherein the haze value of a 0.3 mm thick test piece using the styrenic resin composition according to claim 1 or 2 as a molding raw material is: Below 30%. The styrenic resin composition according to claim 1 or 2, wherein the content of the conjugated diene monomer units constituting the rubber-like polymer is 3 to 13 relative to the entire styrenic resin composition. Mass %. The styrenic resin composition according to claim 1 or 2, wherein the rubber-like polymer particles have an average particle diameter of 0.4 μm or more and 0.95 μm or less. The styrenic resin composition according to claim 1 or 2, which contains 0.03 to 0.7 mass % of a higher fatty acid compound relative to the entire styrenic resin composition. The styrenic resin composition according to claim 1 or 2, further containing 0.001 to 0.5 mass % of an antioxidant based on the entire styrenic resin composition. A molded article formed from the styrenic resin composition according to claim 1 or 2. A carrier tape for transporting electronic parts, which is composed of a base material, and the aforementioned base material has: a plurality of recesses housing electronic components, and an edge capable of being bonded to the covering that seals the recessed portion, in, The aforementioned base material contains the styrenic resin composition according to claim 1 or 2.

Images