JP6741190B1 - Resin composition, molded article, film and method for producing resin composition - Google Patents

Abstract

Provided are a resin composition obtained by blending a polystyrene resin with a polyamide resin, a molded article, a film, and a method for producing the resin composition. The total amount of the polyamide resin (B) and the polyamide resin (C) is 85 to 15 parts by mass with respect to 15 to 85 parts by mass of the polystyrene resin (A). Constituting a structural unit derived from an acid, 70 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine, more than 90 mol% of the structural unit derived from the dicarboxylic acid is derived from adipic acid, the polyamide resin (C) is composed of a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, 70 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine, of the structural unit derived from the dicarboxylic acid, 40 to 60 mol% is derived from α,ω-straight chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 60 to 40 mol% is derived from isophthalic acid (however, the total does not exceed 100 mol%. ), The resin composition whose mass ratio ((B):(C)) of the said polyamide resin (B) and the said polyamide resin (C) is 95:5 to 65:35.

Description

The present invention relates to a resin composition, a molded article and a film using the resin composition. Moreover, it is related with the manufacturing method of a resin composition.

Polystyrene (PS) resin using styrene as a raw material monomer has excellent transparency and is widely used in cassette cases, food containers, household products, and the like. Blending with other resins has been studied in order to improve its physical properties or to enhance its suitability for production.
For example, in Patent Document 1, a stretched thermoplastic resin composition comprising 10 to 98% by weight of a polystyrene resin A and 2 to 90% by weight of a polyamide resin B is measured by a depolarizing strength method of the polyamide resin. It has been proposed that the specified half-crystallization time is specified in a specific range.

JP, 2009-001782, A

As described above, it has been considered to blend another resin with the polystyrene resin to give an additional function. However, when the polystyrene resin is blended with another resin, the transparency may be deteriorated.
In particular, the present inventor studied blending a polystyrene resin with a xylylenediamine-based polyamide resin. However, it was not easy to ensure sufficient transparency in the obtained molded product.
The present invention is intended to solve such a problem, and is a resin composition obtained by blending a polystyrene resin with a xylylenediamine-based polyamide resin, which is a resin composition capable of maintaining excellent transparency. An object of the present invention is to provide a method for producing a product, a molded article, a film and a resin composition.

As a result of studying the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by using, as the xylylenediamine-based polyamide resin blended with the polystyrene resin, one modified with isophthalic acid at a specific ratio.
Specifically, the above problems are solved by the following means <1> to <10>.

<1> Polystyrene resin (A) 15 to 85 parts by mass, and a total of 85 to 15 parts by mass of the polyamide resin (B) and the polyamide resin (C), wherein the polyamide resin (B) is a structural unit derived from a diamine. And composed of structural units derived from dicarboxylic acid, 70 mol% or more of the structural units derived from the diamine are derived from xylylenediamine, and more than 90 mol% of the structural units derived from the dicarboxylic acid are derived from adipic acid, The polyamide resin (C) is composed of a constitutional unit derived from a diamine and a constitutional unit derived from a dicarboxylic acid, and 70 mol% or more of the constitutional unit derived from the diamine is derived from xylylenediamine, and the constitution derived from the dicarboxylic acid. 40 to 60 mol% of the unit is derived from α,ω-straight chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 60 to 40 mol% is derived from isophthalic acid (however, the total exceeds 100 mol%. The resin composition in which the mass ratio ((B):(C)) of the polyamide resin (B) and the polyamide resin (C) is 95:5 to 65:35.
<2> The resin composition according to <1>, wherein 70 mol% or more of the constitutional unit derived from diamine in the polyamide resin (B) is derived from metaxylylenediamine.
<3> The resin composition according to <1> or <2>, in which 70 mol% or more of the constituent units derived from the diamine in the polyamide resin (C) is derived from metaxylylenediamine.
<4> The resin composition according to any one of <1> to <3>, wherein 60 to 40 mol% of the constitutional unit derived from a dicarboxylic acid in the polyamide resin (C) is derived from adipic acid.
<5> The polyamide resin (B) is a crystalline polyamide resin, the polyamide resin (C) is an amorphous polyamide resin, and a structural unit constituting the polyamide resin (B), and the polyamide resin The resin composition according to any one of <1> to <4>, in which 60% by mole or more of the constituent units constituting (C) are common.
<6> 70 mol% or more of the diamine-derived constitutional units in the polyamide resin (B) are derived from metaxylylenediamine, and 70 mol% or more of the diamine-derived constitutional units in the polyamide resin (C) are metaxylylene diamine. 60 to 40 mol% of the constitutional unit derived from an amine and derived from a dicarboxylic acid in the polyamide resin (C) is derived from adipic acid, the polyamide resin (B) is a crystalline polyamide resin, and the polyamide resin (C ) Is an amorphous polyamide resin, and 60 mol% or more of the constitutional unit constituting the polyamide resin (B) and the constitutional unit constituting the polyamide resin (C) are common, <1> Resin composition.
<7> Any one of <1> to <6>, wherein the mass ratio ((B):(C)) of the polyamide resin (B) and the polyamide resin (C) is 90:10 to 70:30. The resin composition according to item 4.
<8> A molded product formed from the resin composition according to any one of <1> to <7>.
<9> A film formed from the resin composition according to any one of <1> to <7>.
<10> The method for producing a resin composition according to any one of <1> to <7>, wherein the polyamide resin (B) and the polyamide resin (C) are melt-kneaded, and further, A method for producing a resin composition, which comprises adding a polystyrene resin (A) and melt-kneading.

According to the present invention, it is possible to provide a resin composition, a molded article, a film, and a method for producing a resin composition, which is a blend of a polystyrene resin and a xylylenediamine-based polyamide resin and maintains transparency.
Further, it has become possible to provide a resin composition having excellent transparency, high chemical resistance, pencil hardness and oxygen barrier property.

The details of the present invention will be described below. In addition, in this specification, "-" is used in the meaning including the numerical values described before and after it as the lower limit and the upper limit.
In the present specification, the xylylenediamine-based polyamide resin refers to a polyamide resin in which 70 mol% or more of the constituent units derived from diamine are derived from xylylenediamine.

The resin composition of the present invention contains a total of 85 to 15 parts by mass of the polyamide resin (B) and the polyamide resin (C) with respect to 15 to 85 parts by mass of the polystyrene resin (A), and the polyamide resin (B) is A diamine-derived constitutional unit and a dicarboxylic acid-derived constitutional unit, 70 mol% or more of the diamine-derived constitutional unit is derived from xylylenediamine, and more than 90 mol% of the dicarboxylic acid-derived constitutional unit is adipine. Derived from an acid, the polyamide resin (C) is composed of a constitutional unit derived from a diamine and a constitutional unit derived from a dicarboxylic acid, and 70 mol% or more of the constitutional unit derived from the diamine is derived from xylylenediamine, Of the constituent units derived from dicarboxylic acid, 40 to 60 mol% are derived from α,ω-straight chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 60 to 40 mol% are derived from isophthalic acid (however, the total is It does not exceed 100 mol %), and the mass ratio ((B):(C)) of the polyamide resin (B) and the polyamide resin (C) is 95:5 to 65:35. ..
This makes it possible to blend with the xylylenediamine-based polyamide resin while maintaining the excellent transparency of the polystyrene resin. Further, it becomes possible to improve chemical resistance, hardness and oxygen barrier property.
If the thermoplastic resin has a different refractive index, it becomes difficult to be transparent even when blended. Therefore, it was difficult to blend the polystyrene resin and the polyamide resin, particularly the xylylenediamine-based polyamide resin. In the present invention, a polystyrene resin and a xylylenediamine-based polyamide resin have been successfully blended by using a high-refractive-index xylylenediamine-based polyamide resin obtained by modifying the xylylenediamine-based polyamide resin with isophthalic acid. Even if there is an interface between the xylylenediamine-based polyamide resin that has not been modified with isophthalic acid and the polystyrene resin, the presence of the xylylenediamine-based polyamide resin that has been modified with isophthalic acid makes it difficult for light to diffusely reflect at that interface, making it transparent. It has become possible to improve the sex. Further, they have found that good chemical resistance, hardness and oxygen barrier property can be obtained.
In the present specification, the term “transparent” means colorless and transparent unless otherwise specified, but it also means that a colored semitransparent state may be used within a range suitable for various applications.

<Polystyrene resin (A)>
As the polystyrene resin (A) used in the resin composition of the present invention, those generally used as this type of resin can be widely adopted.
The polystyrene resin is usually an amorphous resin.
Specific examples of the polystyrene resin include a polymer of a styrene-based monomer or a copolymer of a styrene-based monomer and another monomer copolymerizable therewith. Examples of the styrene-based monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-t-butylstyrene, alkyl-substituted styrene such as 2,4-dimethylstyrene, and α-methyl. Styrene, α-alkyl-substituted styrene such as α-methyl-4-methylstyrene, halogenated styrene such as chlorostyrene and bromostyrene, halogen-substituted alkylstyrene, polyalkoxystyrene, polycarboxyalkylstyrene, polyalkylether styrene, polyalkyl Mention may be made of silylstyrene.

Other monomers copolymerizable with the styrene-based monomer include acrylic acid or methacrylic acid, methyl acrylate or methyl methacrylate, ethyl acrylate or ethyl methacrylate, butyl acrylate or butyl methacrylate, and 2-ethylhexyl acrylate. Acrylic acid or methacrylic acid ester such as methacrylic acid-2-ethylhexyl, unsaturated nitrile such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide, N-methylmaleimide, N-substituted maleimide such as N-ethylmaleimide, etc. And maleic acid or its derivative.
Further, the polystyrene resin (A) includes high impact polystyrene, styrene-conjugated diene block copolymer, hydrogenated product of styrene-conjugated diene block copolymer, ABS (rubber graft styrene-acrylonitrile copolymer), MBS. (Rubber-grafted styrene-methyl methacrylate copolymer), rubber-grafted styrene-(meth)acrylic acid ester copolymer and the like can also be used. However, the polystyrene resin (A) used in the present invention is preferably not a so-called elastomer (impact modifier).
Among them, the resin composition of the present invention may be a copolymer of styrene and another monomer or a derivative thereof that is copolymerizable with styrene, as long as the effects of the invention are not impaired. The homopolymer of styrene in the present invention means that 80% by mass or more of the monomers constituting the polymer are styrene-based monomers.
The method for synthesizing the polystyrene resin is not particularly limited, and a general method can be adopted. For example, it can be obtained by radically polymerizing styrene using benzoyl peroxide as an initiator (radical initiator). The polystyrene obtained at this time usually has an atactic structure. Atactic polystyrene is a thermoplastic resin, is inexpensive, and can be preferably used because it has advantages such as easy injection molding. Alternatively, in consideration of the environment, a recycled material of polystyrene resin may be used.

The polystyrene resin (A) has a weight average molecular weight of preferably 80,000 or more, more preferably 100,000 or more, and further preferably 120,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 800,000 or less, and further preferably 500,000 or less.

The content of the polystyrene resin (A) may be appropriately determined, but in the resin composition, it is preferably 15% by mass or more, more preferably 25% by mass or more, and 40% by mass or more. Is more preferable. The upper limit is preferably 85% by mass or less, more preferably 80% by mass or less, and preferably 70% by mass or less.

<Polyamide resin (B)>
The polyamide resin (B) used in the present invention is composed of a constitutional unit derived from a diamine and a constitutional unit derived from a dicarboxylic acid, and 70 mol% or more of the constitutional unit derived from the diamine is derived from xylylenediamine and derived from a dicarboxylic acid. More than 90 mol% of the constituent units are derived from adipic acid.

In the polyamide resin (B), preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, still more preferably 99 mol% or more of the structural unit derived from diamine is derived from xylylenediamine. To do. The xylylenediamine is preferably metaxylylenediamine and paraxylylenediamine, and more preferably metaxylylenediamine. One example of the preferred embodiment of the polyamide resin (B) in the present invention is a polyamide resin in which 70 mol% or more of the constituent units derived from diamine are derived from metaxylylenediamine.

Diamines other than xylylenediamine that can be used as the raw material diamine component of the polyamide resin (B) include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylene. Aliphatic diamines such as diamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1 ,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl) ) Decalin, alicyclic diamines such as bis(aminomethyl)tricyclodecane, bis(4-aminophenyl)ether, paraphenylenediamine, and diamines having an aromatic ring such as bis(aminomethyl)naphthalene may be exemplified. It is possible to use one kind or a mixture of two or more kinds.
When a diamine other than xylylenediamine is used as the diamine component, it is used in an amount of 30 mol% or less of the constitutional unit derived from the diamine, more preferably 1 to 25 mol %, and particularly preferably 5 to 20 mol %.

In the polyamide resin (B), 90 mol% or more, preferably 95 mol% or more, and more preferably 99 mol% or more of the constituent units derived from dicarboxylic acid are derived from adipic acid.
Preferred dicarboxylic acids other than adipic acid to be used as the raw material dicarboxylic acid component of the polyamide resin (B) include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid. Phthalic acid compounds such as aliphatic dicarboxylic acids, terephthalic acid, orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1 Naphthalene dicarboxylic acid such as 1,6-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid An acid can be exemplified, and one kind or a mixture of two or more kinds can be used.
When a dicarboxylic acid other than adipic acid is used as the dicarboxylic acid component, it is less than 10 mol% and preferably 5 mol% or less of the constitutional unit derived from the dicarboxylic acid.
If used, the other dicarboxylic acid is preferably an aliphatic dicarboxylic acid.

The polyamide resin (B) used in the present invention is composed of a constitutional unit derived from a dicarboxylic acid and a constitutional unit derived from a diamine, but a constitutional unit other than the constitutional unit derived from a dicarboxylic acid and the constitutional unit derived from a diamine, or a terminal. Other structural moieties such as groups may be included. Examples of other structural units include lactams such as ε-caprolactam, valerolactam, laurolactam, and undecalactam, and structural units derived from aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. It is not limited to these. Furthermore, the polyamide resin (B) used in the present invention may contain trace components such as additives used in the synthesis. The polyamide resin (B) is usually composed of 95% by mass or more, preferably 98% by mass or more, of a structural unit derived from a dicarboxylic acid or a structural unit derived from a diamine.

The number average molecular weight (Mn) of the polyamide resin (B) is preferably 10,000 or more, more preferably 15,000 or more. The upper limit of the number average molecular weight of the polyamide resin (B) is not particularly limited, but may be, for example, 100,000 or less, and may be 50,000 or less and 40,000 or less. The number average molecular weight in the present invention is measured according to the method described in paragraph 0016 of WO 2017/090556, the contents of which are incorporated herein.
The polyamide resin (B) is usually a crystalline polyamide resin, and its melting point is preferably 190 to 300°C, more preferably 200 to 270°C, and further preferably 210 to 250°C. preferable. The melting point in the present invention is measured according to the description in paragraph 0017 of JP-A-2016-216661, and the contents thereof are incorporated herein.

The resin composition of the present invention preferably contains the polyamide resin (B) in an amount of 10% by mass or more, more preferably 15% by mass or more, further preferably 20% by mass or more, and further preferably 25% by mass or more. It is even more preferable, and it is even more preferable that the content be 30% by mass or more. The resin composition of the present invention preferably contains the polyamide resin (B) in an amount of 70% by mass or less, 55% by mass or less, and even less than 50% by mass, and even more It may be 48 mass% or less.

<Polyamide resin (C)>
The polyamide resin (C) used in the resin composition of the present invention is composed of a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, and 70 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine. However, 40 to 60 mol% of the constituent unit derived from the dicarboxylic acid is derived from α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 60 to 40 mol% is derived from isophthalic acid (however, , And the total does not exceed 100 mol %).

In the polyamide resin (C) used in the present invention, 70 mol% or more of the constituent units derived from diamine are derived from xylylenediamine, preferably 80 mol% or more, more preferably 90 mol% or more, and further preferably 95 mol% or more, more preferably 99 mol% or more, is derived from xylylenediamine. The xylylenediamine is preferably metaxylylenediamine.

Diamines other than xylylenediamine include aromatic diamines such as paraphenylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine. And aliphatic diamines such as octamethylene diamine and nonamethylene diamine. These other diamines may be used alone or in combination of two or more.

In the polyamide resin (C) used in the present invention, 40 to 60 mol% is derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The lower limit of the proportion of the α,ω-straight chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferably 42 mol% or more, and more preferably 45 mol% or more. The upper limit is preferably 58 mol% or less, more preferably 55 mol% or less.

Examples of the α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid and dodecanedioic acid. Aliphatic dicarboxylic acids are exemplified, adipic acid and sebacic acid are preferable, and adipic acid is more preferable. The α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms may be one type or two or more types.

In the polyamide resin (C) used in the present invention, the ratio of the constitutional unit derived from isophthalic acid is 60 to 40 mol% in all the dicarboxylic acids constituting the constitutional unit derived from dicarboxylic acid. The lower limit value of the ratio of the constitutional unit derived from isophthalic acid is preferably 42 mol% or more, more preferably 45 mol% or more. The upper limit of the ratio of the constitutional unit derived from isophthalic acid is preferably 58 mol% or less, more preferably 55 mol% or less.

The constitutional unit derived from dicarboxylic acid may contain other dicarboxylic acid other than isophthalic acid and α,ω-straight chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms. Other dicarboxylic acids include phthalic acid compounds such as terephthalic acid and orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, Naphthalenedicarboxylic acids such as 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid An acid compound etc. can be illustrated and it can be used 1 type or in mixture of 2 or more types.

In the polyamide resin (C), the total of constituent units derived from isophthalic acid and constituent units derived from α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms is 90 mol% or more of the constituent units derived from dicarboxylic acid. It is preferable to occupy, more preferably 95 mol% or more, still more preferably 98 mol% or more, still more preferably 99 mol% or more. The upper limit is 100 mol %.

The polyamide resin (C) used in the present invention is composed of a constitutional unit derived from a dicarboxylic acid and a constitutional unit derived from a diamine, but a constitutional unit other than the constitutional unit derived from the dicarboxylic acid and the constitutional unit derived from the diamine, or a terminal. Other structural moieties such as groups may be included. Examples of other structural units include lactams such as ε-caprolactam, valerolactam, laurolactam, and undecalactam, and structural units derived from aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. It is not limited to these. Further, the polyamide resin (C) used in the present invention may contain trace components such as additives used in the synthesis. The polyamide resin (C) is usually composed of 95% by mass or more, preferably 98% by mass or more, of a structural unit derived from a dicarboxylic acid or a structural unit derived from a diamine.

In the present invention, the polyamide resin (C) is preferably an amorphous polyamide resin. The transparency can be further improved by using the amorphous polyamide resin.
In the present specification, the amorphous resin refers to a resin having a crystal melting enthalpy ΔHm of less than 10 J/g.

The number average molecular weight (Mn) of the polyamide resin (C) used in the present invention has a lower limit value of preferably 6,000 or more, more preferably 10,000 or more, and 12,000 or more. Good. Further, the upper limit of the number average molecular weight (Mn) is preferably 50,000 or less, more preferably 30,000 or less, and 25,000 or less, 18,000 or less, 15,000 or less. It may be. The number average molecular weight in the present invention is measured according to the method described in paragraph 0016 of WO 2017/090556, the contents of which are incorporated herein.

Although the content of the polyamide resin (C) may be appropriately determined, it is preferably 1% by mass or more and more preferably 4% by mass or more in the resin composition. The upper limit is preferably 20% by mass or less, 15% by mass or less, or 12% by mass or less.

Next, an example of a method for producing the polyamide resins (B) and (C) used in the present invention will be described. The polyamide resins (B) and (C) can be produced by a production method including polycondensation of a diamine and a dicarboxylic acid in the presence of a catalyst. The diamine and dicarboxylic acid here have the same meanings as described above, and the preferable ranges are also the same. Known catalysts can be used, and examples of the catalyst containing sodium include sodium hypophosphite, sodium phosphite, sodium hydrogen phosphite and the like. Examples of the catalyst containing calcium include calcium hypophosphite and calcium phosphite.

Polycondensation is usually a melt polycondensation method, and a method may be mentioned in which a raw material dicarboxylic acid is added dropwise to a molten raw material dicarboxylic acid, the temperature is raised under pressure, and polymerization is performed while removing condensed water. Alternatively, a method may be mentioned in which a salt composed of a raw material diamine and a raw material dicarboxylic acid is heated in the presence of water under pressure to polymerize in a molten state while removing added water and condensed water.

<Blend form>
The resin composition of the present invention contains a total of 85 to 15 parts by mass of the polyamide resin (B) and the polyamide resin (C) with respect to 15 to 85 parts by mass of the polystyrene resin (A). Preferably, the total amount of polystyrene resin (A), polyamide resin (B) and polyamide resin (C) may exceed 100 parts by mass, but 100 parts by mass is preferred.
In the resin composition of the present invention, when the total amount of the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C) is 100 parts by mass, the lower limit of the ratio of the polystyrene resin (A) is 18 It is preferably not less than 20 parts by mass, more preferably not less than 20 parts by mass, and further may be not less than 30 parts by mass, not less than 40 parts by mass, and not less than 55 parts by mass, depending on the application. Moreover, when the total of the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C) is 100 parts by mass, the upper limit of the ratio of the polystyrene resin (A) is preferably 82 parts by mass or less. It is more preferably 80 parts by mass or less, and may be 70 parts by mass or less, 65 parts by mass or less, and 55 parts by mass or less, depending on the application.
In the resin composition of the present invention, the mass ratio ((B):(C)) of polyamide resin (B) and polyamide resin (C) is 95:5 to 65:35, preferably 90:10. ˜70:30, and more preferably 85:15 to 75:25.
In the present invention, the ratio of the total of the polyamide resin (B) and the polyamide resin (C) to the polystyrene resin (A), and the ratio of the polyamide resin (B) and the polyamide resin (C) may be within the above ranges. This is important, because it allows the molded article to maintain high transparency, and further imparts excellent chemical resistance, hardness and oxygen barrier properties.

The polyamide resin (B) and the polyamide resin (C) preferably have 60 mol% or more of their constituent units in common, more preferably 65 mol% or more in common, and 70 mol% or more in common. Is more preferable. The upper limit is preferably 80 mol% or less, more preferably 75 mol% or less. The common constitutional unit here means, for example, of the raw material monomers constituting the polyamide resin (B) contained in the resin composition, the total proportion of metaxylylenediamine and adipic acid is 95 mol% of all the raw material monomers. When the total proportion of metaxylylenediamine and adipic acid in the raw material monomers constituting the polyamide resin (C) contained in the resin composition is 75 mol% of all the raw material monomers, 75 mol% of the constitutional unit % Is considered to be common.

The amount of isophthalic acid in the resin composition of the present invention is the amount of structural units derived from isophthalic acid when the total amount of structural units derived from dicarboxylic acid in polyamide resin (B) and polyamide resin (C) is 100 mol %. It can be evaluated by the ratio (mol %). In the resin composition of the present invention, the ratio of the constitutional unit derived from isophthalic acid is preferably 1 mol% or more, more preferably 3 mol% or more, still more preferably 5 mol% or more. The upper limit is preferably 25 mol% or less, more preferably 22.5 mol% or less, more preferably 20 mol% or less, and further preferably 10 mol% or less.

The resin composition of the present invention may consist of the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C) alone, or may contain other components. As the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C), one kind may be used, or two or more kinds may be contained. When two or more kinds are included, it is preferable that the total satisfies the above range.

In the resin composition of the present invention, the components other than the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C) are other than the above-mentioned polyamide resins (B) and (C). Polyamide resin, thermoplastic resin other than polyamide resin, lubricant, filler, matting agent, heat resistance stabilizer, weather resistance stabilizer, ultraviolet absorber, plasticizer, flame retardant, antistatic agent, anti-coloring agent, gelation inhibitor And the like, and these can be added as necessary. Each of these additives and the like may be of one type or of two or more types.
Examples of the lubricant include higher fatty acid metal salts, and calcium stearate is preferable.

Other polyamide resins include polyamide 6, polyamide 66, polyamide 46, polyamide 6/66 (copolymer consisting of polyamide 6 component and polyamide 66 component), polyamide 610, polyamide 612, polyamide 11, polyamide 12, MPXD6 (polyamide). Metaparaxylylene adipamide), MXD10 (polymetaxylylene sebacamide), MPXD10 (polymetaparaxylylene sebasamide) and PXD10 (polyparaxylylene sebacamide), polyamide 6I, polyamide 6T, polyamide 9I , Polyamide 9T, polyamide 10T, polyamide 6I/6T, polyamide 9I/9T and the like. Each of these other polyamide resins may be of one type or of two or more types.

Examples of thermoplastic resins other than polyamide resins include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, polystyrene resins, acrylic resins, and the like. The thermoplastic resins other than these polyamide resins may be of one type or of two or more types.

In the resin composition of the present invention, the total content of the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C) can be 98% by mass or more of the resin component contained in the resin composition, It may be 99% by mass or more.
In the resin composition of the present invention, the total content of the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C) is 90 mass% or more (preferably 95 mass% or more, It is preferably 99% by mass or more).

The resin composition of the present invention can be manufactured by a known method. For example, it can be obtained by melt-kneading the polystyrene resin (A), the polyamide resin (B) and the polyamide resin (C). Particularly, in the production method of the present invention, it is preferable to melt-knead the polyamide resin (B) and the polyamide resin (C), and then add the polystyrene resin (A) and melt-knead.

The oxygen permeability coefficient of the resin composition of the present invention is 11 cc·mm/day·m ² ·atm or less when formed into a film having a thickness of 100 μm and measured at a measurement temperature of 25° C. and a relative humidity of 60%. It is preferably 5 cc·mm/day·m ² ·atm or less, more preferably 1 cc·mm/day·m ² ·atm or less, still more preferably 0.5 cc·mm/day·m ^2. -Atm or less is more preferable, and 0.3 cc-mm/day-m ² -atm or less is still more preferable. As a lower limit value, the ideal is 0 cc·mm/day·m ² ·atm, but even if it is 0.001 cc·mm/day·m ² ·atm or more, the required performance is satisfied.
The details of the method for measuring the oxygen barrier property follow the method described in Examples below.

<Molded products>
The molded article of the present invention is formed from the resin composition of the present invention.
The specific method for producing a molded article using the resin composition of the present invention is not particularly limited, and a molding method generally used for thermoplastic resins can be adopted. Specifically, molding methods such as injection molding, hollow molding, extrusion molding, and press molding can be applied.

Molded products include single-layer films (including single-layer sheets), multi-layer films (including multi-layer sheets), fibers, threads, monofilaments, multifilaments, ropes, tubes, hoses, various molding materials, containers, various parts, and finished products. Examples include products and housings. Further, the molded article (in particular, film, monofilament, multifilament) may be stretched. The molded product may be a thin molded product, a hollow molded product, or the like. Among them, in the present invention, a film (including a sheet) product is preferable from the viewpoint of utilizing the advantage of high transparency. The thickness of the film is preferably 200 μm or less, more preferably 100 μm or less, and further preferably 60 μm or less. It is practical that the lower limit value is 0.1 μm or more. The thick sheet preferably has a thickness of 100 μm or more, more preferably 500 μm or more, still more preferably 1 mm or more. It is practical that the upper limit value is 10 mm or less. Specific examples of the molded product are not particularly limited, but wraps, daily necessities such as food packaging films such as shrink films, pouches of various shapes, container lid materials, bottles, cups, trays, tubes, electronic Transparent materials for display screens of equipment, transparent materials for lighting equipment, surface materials for recording media, packaging materials for pharmaceuticals, transportation equipment parts such as automobiles, general machine parts, precision machine parts, office automation equipment parts, building materials and housing related parts , Medical equipment, leisure sports equipment, play equipment, medical products, etc.

The field of use of the molded article is not particularly limited, but it is a transportation machine part for automobiles, automobile interior parts, general machine parts, precision machine parts, electronic/electric equipment parts, office automation equipment parts, building materials/household equipment-related. Examples include parts, medical devices, leisure sports equipment, play equipment, medical products, food packaging films, decorations, paint and oil containers, defense and aerospace products.

Hereinafter, the present invention will be described more specifically with reference to examples. The materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

<Synthesis Example 1 Synthesis of MXD6>
In a 50 L reactor equipped with a stirrer, a partial condenser, a condenser, a thermometer, a dropping tank and a nitrogen gas introducing pipe, adipic acid 9000 g (61.0 mol), sodium hypophosphite monohydrate 2 0.6 g (100 mass ppm in terms of phosphorus atom concentration in the polyamide resin) and 1.0 g of sodium acetate were charged and sufficiently replaced with nitrogen, and the temperature was raised to 180°C under a small amount of nitrogen stream to make adipic acid uniform. After melting, while stirring the system, 8480 g (62.2 mol) of metaxylylenediamine was added dropwise thereto. During this time, the internal temperature was continuously raised to 245°C. Water generated by polycondensation was removed from the system through a partial condenser and a cooler. After the addition of the meta-xylylenediamine was completed, the internal temperature was further raised to 260° C. and the reaction was continued for 1 hour. Then, the polymer was taken out from the nozzle at the bottom of the reaction vessel as a strand, cooled with water and pelletized to obtain the polymer (MXD6). Obtained.

<Synthesis Example 2 Synthesis of MXD6I-1>
A reaction vessel equipped with a stirrer, a partial condenser, a total condenser, a thermometer, a dropping funnel and a nitrogen introducing tube, and a strand die was precisely weighed with adipic acid of 6,000 g (41.1 mol) and isophthalic acid of 6,820 g ( 41.1 mol), sodium hypophosphite monohydrate 3.6 g (NaH ₂ PO ₂ .H ₂ O) (100 mass ppm in terms of phosphorus atom concentration in the polyamide resin) and 1.1 g of sodium acetate were added. After sufficiently substituting with nitrogen, nitrogen was filled up to an internal pressure of 0.4 MPa, and the system was heated to 190° C. under a small amount of nitrogen stream while stirring.
To this, 11,184 g (82.11 mol) of meta-xylylenediamine was added dropwise with stirring, and the inside of the system was continuously heated while removing the generated condensed water to the outside of the system. After the end of the addition of metaxylylenediamine, the internal temperature was raised, and when the temperature reached 255°C, the pressure inside the reaction vessel was reduced, and the internal temperature was further raised to continue the melt polycondensation reaction at 260°C for 10 minutes. Then, the system was pressurized with nitrogen, and the obtained polymer was taken out from the strand die and pelletized to obtain about 21 kg of polyamide resin (MXD6I-1). It was found that this resin had a crystal melting enthalpy ΔHm of about 0 J/g in the temperature rising process and was amorphous.

<Synthesis Example 3 Synthesis of MXD6I-2>
In Synthesis Example 2, adipic acid 6,000 g (41.06 mol) and isophthalic acid 6,821 g (41.06 mol) were made adipic acid 11,280 g (77.19 mol), and isophthalic acid 819 g (4.93 mol) was added. An isophthalic acid-modified polyamide resin (MXD6I-2) was obtained in the same manner as described above. The isophthalic acid modification ratio here is 6 mol %.

Polystyrene resin (A): Nippon Polystyrene Co., Ltd., GPPS SGP10 mass average molecular weight Mw: 350,000

Examples 1-6, Comparative Examples 1-6
The polyamide resin (B) and the polyamide resin (C) were weighed so as to have the amounts (parts by mass) shown in the following examples (Table 1) and dry-blended. It was charged from the root of a twin-screw extruder (TEM26SX manufactured by Toshiba Machine Co., Ltd.), melted at 270° C. and extruded, and the strand was water-cooled in a water tank and pelletized to prepare pellets. The obtained pellets were vacuum dried at 110° C. (dew point −40° C.) for 24 hours, and then dry blended with the polystyrene resin pellets so that the mass ratios shown in Table 1 were obtained, and an injection molding machine (Sumitomo Heavy Industries Ltd. ), SE130DU-HP), and a test piece of 4 mm×10 mm×80 mm was prepared. The molding was carried out at a cylinder temperature of 280°C and a mold surface temperature of 90°C.
The following evaluations were performed and are shown in Table 1.

<Appearance evaluation>
The test piece was placed on the print. At that time, the visibility of the printed image seen in the background was visually evaluated. The results were divided and compared as follows. Evaluation was carried out by 5 experts and judged by majority vote. The results are shown in Table 1.
(Evaluation)
A: The printed image was easily visible.
B: Although the white turbidity was observed, the printed image was visible.
C: White turbidity was remarkable and the printed image was not visible.

<Chemical resistance>
The above test piece was immersed in toluene under the condition of 23° C., allowed to stand for 5 days, and its appearance was evaluated. The test piece after immersion as described above was placed on the printed matter. At that time, the visibility of the printed image seen in the background was visually evaluated. The results were divided and compared as follows. Evaluation was carried out by 5 experts and judged by majority vote. The results are shown in Table 1.
(Evaluation)
A: The shape of the test piece did not change, and its transparency was not affected.
B: The shape of the test piece did not change, but the transparency deteriorated (visible).
C: The shape of the test piece did not change, but the transparency deteriorated (visible).
D: The shape of the test piece changed and the transparency deteriorated.
In addition, regarding the visibility, it was clouded before immersion, and for those without visibility, "C" when the shape of the test piece did not change, and when there was a change in the shape of the test piece , "D".

<Pencil hardness>
The pencil hardness of the test piece was measured according to ISO 15184.

<Oxygen barrier property>
The polyamide resin (B) and the polyamide resin (C) were weighed so as to have the amounts (parts by mass) shown in the following examples (Table 1) and dry-blended. It was charged from the root of a twin-screw extruder (TEM26SX manufactured by Toshiba Machine Co., Ltd.), melted at 270° C. and extruded, and the strand was water-cooled in a water tank and pelletized to prepare pellets. The obtained pellets were vacuum dried at 110° C. (dew point −40° C.) for 24 hours, and then dry blended with the polystyrene resin pellets so that the mass ratio shown in Table 1 was obtained. , PTM-30), melted and extruded to produce a film having a thickness of 100 μm. The temperature setting of the extruder was set to 270°C.
The oxygen permeation coefficient was measured by cutting out a portion having an area of 50 cm ^{2 from} the film having a thickness of 100 μm obtained above and measuring the temperature at 25° C. and the relative humidity at 60%.
At the time of measurement, OX-TRAN-2/21 (manufactured by MOCON) was used to evaluate the oxygen barrier property when the value was stable.
The unit is cc·mm/day·m ² ·atm.

As can be seen from the above results, when the isophthalic acid-modified polyamide resin (C) having a specific modification rate was contained in a specific amount, the sheet obtained from the resin composition had high transparency and an excellent appearance ( Examples 1-6). Furthermore, by increasing the content of the polyamide resin (C), one having high chemical resistance, pencil hardness, and further oxygen barrier property was obtained.
On the other hand, even a blend of a polystyrene resin and a polyamide resin does not contain the isophthalic acid-modified polyamide resin (C) (Comparative Example 2) and contains a large amount of the isophthalic acid-modified polyamide resin (C) (Comparative Example 3). ), and when using a polyamide resin having a low isophthalic acid modification rate (Comparative Examples 4 to 6), the transparency of the sheet was low and the appearance was inferior (Comparative Example). 1).

Claims (10)

The total amount of the polyamide resin (B) and the polyamide resin (C) is 85 to 15 parts by mass with respect to 15 to 85 parts by mass of the polystyrene resin (A),
The polyamide resin (B) is composed of a constitutional unit derived from a diamine and a constitutional unit derived from a dicarboxylic acid, and 70 mol% or more of the constitutional unit derived from the diamine is derived from xylylenediamine, and the constitution derived from the dicarboxylic acid. More than 90 mol% of the units are derived from adipic acid,
The polyamide resin (C) is composed of a constitutional unit derived from a diamine and a constitutional unit derived from a dicarboxylic acid, and 70 mol% or more of the constitutional unit derived from the diamine is derived from xylylenediamine, and the constitution derived from the dicarboxylic acid. 40 to 60 mol% of the unit is derived from α,ω-straight chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 60 to 40 mol% is derived from isophthalic acid (however, the total exceeds 100 mol%. Nothing),
A resin composition in which the mass ratio ((B):(C)) of the polyamide resin (B) and the polyamide resin (C) is 95:5 to 65:35. The resin composition according to claim 1, wherein 70 mol% or more of the constituent units derived from the diamine in the polyamide resin (B) are derived from metaxylylenediamine. The resin composition according to claim 1 or 2, wherein 70 mol% or more of the constituent units derived from the diamine in the polyamide resin (C) is derived from metaxylylenediamine. The resin composition according to any one of claims 1 to 3, wherein 60 to 40 mol% of the constitutional unit derived from a dicarboxylic acid in the polyamide resin (C) is derived from adipic acid. The polyamide resin (B) is a crystalline polyamide resin, the polyamide resin (C) is an amorphous polyamide resin, and the constitutional unit constituting the polyamide resin (B) and the polyamide resin (C). The resin composition according to any one of claims 1 to 4, wherein 60 mol% or more of the constituent units constituting the are common. 70 mol% or more of the constituent units derived from diamine in the polyamide resin (B) are derived from metaxylylenediamine,
70 mol% or more of the constituent units derived from diamine in the polyamide resin (C) are derived from metaxylylenediamine,
60 to 40 mol% of the structural unit derived from dicarboxylic acid in the polyamide resin (C) is derived from adipic acid,
The polyamide resin (B) is a crystalline polyamide resin, the polyamide resin (C) is an amorphous polyamide resin, and the constitutional unit constituting the polyamide resin (B) and the polyamide resin (C). The resin composition according to claim 1, wherein 60 mol% or more of the constituent units constituting the are common. The resin according to any one of claims 1 to 6, wherein a mass ratio ((B):(C)) of the polyamide resin (B) and the polyamide resin (C) is 90:10 to 70:30. Composition. A molded article formed from the resin composition according to claim 1. A film formed from the resin composition according to claim 1. A method for producing the resin composition according to any one of claims 1 to 7, wherein
A method for producing a resin composition, comprising melt-kneading the polyamide resin (B) and the polyamide resin (C), and further adding the polystyrene resin (A) and melt-kneading.