JP2820947B2 - Styrene resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a styrenic resin composition. More specifically, the present invention relates to a styrenic polymer having a syndiotactic structure, in which a specific block or graft copolymer is compounded together with a polyamide. The present invention relates to a styrene-based resin composition having excellent heat resistance, water resistance, impact resistance and the like.

[Problems to be solved by conventional technology and invention]

In general, polyamide is excellent in moldability and heat resistance and has sufficient rigidity.
It is used as a molding material for various products such as electric products and parts of machine tools.

However, although polyamide has such excellent properties, it has a drawback that it is hard to say that it is sufficient in terms of water resistance.

By the way, recently, the group of the present inventors succeeded in developing a styrenic polymer having high syndiotacticity, and further developed a thermoplastic resin composition in which other components were blended with this styrenic polymer. (Japanese Patent Laid-Open No. 62-1048
No. 18, No. 62-257950).

The styrenic polymer was blended with polyamide to attempt to improve the above-mentioned disadvantages. However, a composition of a resin essentially incompatible with each other, such as polyamide and polystyrene, has excellent heat resistance, but has an interface between the phases. Since the reduction of mechanical properties due to insufficient strength of the steel cannot be avoided, the reforming effect by blending has a limit.

Therefore, the present inventor has solved the above-mentioned problems and improved the compatibility between the styrene-based polymer having a syndiotactic structure and the polyamide resin, so as not to impair the mechanical properties of the polyamide. Intensive research was conducted to develop a composition having greatly improved properties.

[Means for solving the problem]

As a result, the polyamide and the styrenic polymer,
By blending a specific block copolymer or graft copolymer, the compatibility of each composition is improved and excellent in mechanical strength, impact resistance, heat resistance, water resistance, etc. without impairing the original physical properties It was found that a resin composition was obtained. The present invention has been completed based on such findings.

That is, the present invention provides: (a) 5 to 95% by weight of a styrenic polymer mainly having a syndiotactic structure, (b) 95 to 5% by weight of a polyamide, and a total of 100 parts by weight of the components (a) and (b). (C) an AB type block copolymer, an A grafted B copolymer and a B grafted A copolymer modified by graft polymerization of an unsaturated carboxylic acid or a derivative thereof. 1 to 50 parts by weight of one or more selected block or graft copolymers [where A represents atactic polystyrene and B represents polybutadiene, polyisoprene, hydrogenated polybutadiene and hydrogenated polyisoprene And one or more polymers. ] (Hereinafter referred to as the first invention), and (a) 5-95% by weight of a styrene-based polymer mainly having a syndiotactic structure, and (b) polyamide 95. (C) an AB type block copolymer modified by graft polymerization of an unsaturated carboxylic acid or a derivative thereof with respect to 100% by weight of a total of the components (a) and (b). One or more blocks selected from A-grafted B copolymer and B-grafted A copolymer or X parts by weight of graft copolymer; and (d) an AB type block copolymer, One or more blocks or graft copolymers Y selected from A-grafted B copolymer and B-grafted A copolymer
Parts by weight [where A represents atactic polystyrene, and B represents one or more polymers selected from polybutadiene, polyisoprene, hydrogenated polybutadiene and hydrogenated polyisoprene. X and Y simultaneously satisfy the following relationship: 1 part by weight ≦ X + Y ≦ 50 parts by weight 1 part by weight ≦ X ≦ 50 parts by weight 0 parts by weight ≦ Y ≦ 49 parts by weight] Hereinafter, referred to as a second invention).

As described above, the resin composition of the first invention comprises (a)
(B) and (c) are the main components. Here, the component (a) is mainly a styrene polymer having a syndiotactic structure. The term “syndiotactic structure” of the styrene polymer mainly means that the stereochemical structure is mainly a syndiotactic structure; It has a steric structure in which phenyl groups and substituted phenyl groups, which are side chains, are alternately located in opposite directions to the main chain formed from carbon bonds, and its tacticity is determined by nuclear magnetic resonance using isotope carbon ( ¹³ C-NMR method).
Tacticity measured by the ¹³ C-NMR method can be represented by the abundance ratio of a plurality of continuous structural units, for example, a dyad for two, a triad for three, and a pentad for five. However, the styrenic polymer having a predominantly syndiotactic structure as referred to in the present invention is usually 75% or more, preferably 85% or more in a dyad, or 30% or more, preferably 50% in a pentad (racemic pentad). Polystyrene, poly (alkyl styrene), poly (halogenated styrene), poly (alkoxy styrene), poly (vinyl benzoate) having the above syndiotacticity and mixtures thereof, or copolymers containing these as main components Refers to coalescence. The poly (alkyl styrene) includes poly (methyl styrene), poly (ethyl styrene), poly (isopropyl styrene), poly (tertiary butyl styrene) and the like, and poly (halogenated styrene) includes Examples include poly (chlorostyrene), poly (bromostyrene), and poly (fluorostyrene). Examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene). Of these, particularly preferred styrene polymers include polystyrene, poly (p-methylstyrene),
Poly (m-methylstyrene), poly (p-tert-butylstyrene), poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), and styrene and p-methylstyrene And copolymers thereof.

The molecular weight of the styrenic polymer used in the present invention is not limited, but preferably has a weight average molecular weight of 10,000 or more, and most preferably 50,000 or more. Further, the molecular weight distribution is not limited in its width, and various molecular weight distributions can be applied. Such a styrene-based polymer having a predominantly syndiotactic structure is, for example, a styrene-based polymer in an inert hydrocarbon solvent or in the absence of a solvent, using a titanium compound and a condensation product of water and a trialkylaluminum as a catalyst. It can be produced by polymerizing a monomer (a monomer corresponding to the above-mentioned styrene-based polymer) (JP-A-62-187708).

Next, in the present invention, the polyamide used as the component (b) is not particularly limited, and a polyamide obtained by copolymerization of a diamine and a dicarboxylic acid, self-condensation of an ω-amino acid, ring-opening polymerization of a lactam ring, and the like are used. be able to. Specifically, polyhexamethylene adipamide,
Polyhexamethylene azeramid, polyhexamethylene sebacamide, polyhexamethylene dodecanoamide, polybis (4-aminocyclohexyl) methane dodecanoamide, polycaprolactam, polylauric lactam, poly-11-aminoundecanoic acid, metaxylyl Examples include lenadipamide or a copolymer thereof. The molecular weight of the polyamide is not particularly limited as long as it is a molecular weight sufficient to produce a molded article, and may be appropriately selected according to a target molded article, a molding method, and the like. Usually, the number average molecular weight is 5,000 to 200,000, preferably 7,000 to 100,000. If the molecular weight is too small, molding becomes difficult, which is not preferable.

In the resin composition of the present invention, the mixing ratio of the components (a) and (b) is 5 to 95% by weight, preferably 15% by weight, based on the total amount of the components (a) and (b). To 85% by weight, and the component (b) is 95 to 5% by weight, preferably 85 to 15% by weight. Here, if the blending ratio of the polyamide as the component (b) is less than 5% by weight, the toughness and mechanical strength of the obtained composition decrease, and if it exceeds 95% by weight, the hot water resistance of the composition is insufficient. Is not preferred.

The resin composition of the present invention further comprises a block or graft copolymer modified by graft copolymerization of the component (a), component (b) with an unsaturated carboxylic acid or a derivative thereof as component (c). I do. In the component (c), various block copolymers can be used as a modified block copolymer. When the block copolymer is represented as an AB type, the one corresponding to A is atactic polystyrene. And B are one or more polymers selected from polybutadiene, polyisoprene, hydrogenated polybutadiene, and hydrogenated polyisoprene.

Further, in the component (c), there are various graft copolymers to be modified. If the graft copolymers usable here are indicated by using the above-mentioned A and B, A
It can be represented as a grafted B copolymer or a B grafted A copolymer.

As the component (c) of the present invention, one or more of an AB type block copolymer, an A-grafted B copolymer and a B-grafted A copolymer may be appropriately used in combination. Can be.

In the above copolymer, the content of A and B is:
Although not particularly limited, it is preferable that A is in the range of 10 to 70 mol% and B is in the range of 90 to 30 mol%. If A is less than 10 mol%, the affinity with the styrene polymer having a syndiotactic structure will be poor, and if it exceeds 70 mol%, the flexibility of the resulting composition will be poor.

The block or graft copolymer described here is the same as the component (d) of the second invention described later.

The component (c) of the present invention is obtained by modifying the above block or graft copolymer by graft copolymerization with an unsaturated carboxylic acid or a derivative thereof. Here, unsaturated carboxylic acid or its derivative component includes unsaturated monocarboxylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid or maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrofuranic acid, methyltetrahydroacid. Phthalic acid, endocis-bicyclo [2.2.
1] Hept-5-ene-2,3-dicarboxylic acid, methyl-endocis-bicyclo [2.2.1] hept-5-ene-2,3-
And unsaturated dicarboxylic acids such as dicarboxylic acids. Further, it can be used for derivatives of unsaturated acids such as acid halides, amino, imides, acid anhydrides and esters of these unsaturated carboxylic acids. Specific examples include maleenyl chloride, maleimide, maleic anhydride, chloromaleic anhydride, butenylsuccinic anhydride, tetrahydrophthalic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Of these, unsaturated dicarboxylic acids and acid anhydrides thereof are particularly preferred.

The component (c) of the composition of the present invention is obtained by graft copolymerizing the unsaturated carboxylic acid or a derivative thereof as described above,
The block or graft copolymer is modified. The component (c) can be produced by a usual method for producing a graft copolymer.
Here, the amount of the unsaturated carboxylic acid or derivative used is not particularly limited, but is generally in the range of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, based on the block or graft copolymer. If it is less than 0.01% by weight, the mechanical properties of the resulting composition will be insufficient. On the other hand, if the content exceeds 10% by weight, the reaction with the component (b) becomes excessive, which causes a disadvantage that a gel is formed. In particular, in the second invention described later, the affinity with the component (d) becomes poor.

In addition, for particularly efficient graft copolymerization,
The reaction is preferably performed in the presence of a radical generator.
Examples of the radical generator to be used include commonly used organic peroxides and diazo compounds. In particular,
Benzoyl peroxide, dicumyl peroxide, di-
tert-butyl peroxide, tert-butyl cumyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, azobisisobutyronitrile and the like. The amount of the radical generator used is 0.01% by weight or more, preferably 0.03 to 1% by weight, based on the graft copolymerization.

 Specifically, the following manufacturing method can be mentioned.

(1) A method in which a radical generator and an unsaturated carboxylic acid or a derivative thereof are added to a solution containing a block or graft copolymer, and the mixture is stirred at a temperature of 40 to 200 ° C. for several tens minutes to several hours, (2) substantially Solvent-free system at a temperature of 130
For example, a method of melting and kneading the components in a temperature range of from 0 to 350 ° C for 20 seconds to 30 minutes, preferably 40 seconds to 5 minutes is employed.

The resin composition of the present invention comprises the component (c) described above as the component (a).
And 1 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the total of components (b). When the compounding ratio of the component (c) is less than 1 part by weight,
The effect of reinforcing the interface between the component (a) and the component (b) is not sufficient, and the impact resistance is low. If it exceeds 50 parts by weight, the rigidity and heat resistance of the composition are impaired, gelation due to excessive reaction, The problem of surface roughness of the molded article arises.

The first invention is a resin composition obtained by blending the components (a), (b) and (c) in predetermined amounts as described above.

On the other hand, the second invention is a resin composition obtained by blending a block or graft copolymer as the component (d) with the components (a), (b) and (c) described above. The component (d) is an unmodified block or graft copolymer before the graft copolymerization and modification with the unsaturated carboxylic acid or the derivative thereof of the component (c) described above, and is the same as that described above. It is.

In the second invention, the mixing ratio of the components (a) and (b) is exactly the same as in the first invention. Furthermore, component (c) is added to X with respect to a total of 100 weights of component (a) and component (b).
The resin composition of the present invention can be obtained by mixing the parts by weight and the Y part by weight with the component (d). Here, X and Y must simultaneously satisfy the following expressions. That is, 1 part by weight ≦ X + Y ≦ 50 parts by weight 1 part by weight ≦ X ≦ 50 parts by weight 0 part by weight ≦ Y ≦ 49 parts by weight The total X + Y of the components (c) and (d) is 1 to 50 parts by weight,
Preferably it is 5 to 40 parts by weight. If X + Y is less than 1 part by weight, the impact resistance of the composition will be low, and if it exceeds 50 parts by weight, the composition will have low rigidity and poor moldability, which is not preferable. Here, X is 1 to 50 parts by weight, preferably 5 to 40 parts by weight. When X is less than 1 part by weight,
The compatibility cannot be improved, and the impact resistance decreases. On the other hand, if it exceeds 50 parts by weight, rigidity and formability become poor,
Not preferred. Further, Y is 0 to 49 parts by weight, preferably 0 to 49 parts by weight.
3939 parts by weight. If it exceeds 49 parts by weight, rigidity and formability will be poor.

The resin composition of the second invention comprises the above (a), (b),
It can be obtained by blending the components (c) and (d) in predetermined amounts.

The resin composition of the present invention comprises the above-mentioned components (a), (b) and (c) as main components and (a), (b),
The components (c) and (d) are the main components, but as long as the characteristics of each component are not impaired, inorganic fillers, nucleating agents, lubricants, plasticizers, antioxidants, ultraviolet absorbers, heat Various additives such as a stabilizer, a flame retardant, an antistatic agent, and a coloring agent can be blended. Here, there are various kinds of inorganic fillers, which may be appropriately selected according to the purpose. Specifically, glass fiber, carbon fiber, alumina fiber, carbon black, graphite, titanium dioxide, silica, talc, mica, calcium carbonate, calcium sulfate, barium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, oxysulfate, oxidation Examples include tin, alumina, kaolin, silicon carbide, metal powder, and mixtures thereof.

The resin composition of the present invention comprises the components (a), (b) and (c) described above, or the components (a), (b), (c) and (d), and an inorganic filler added as necessary. And various additives are blended and blended, and the blending method may be an appropriate method depending on the situation such as a conventionally known melt-kneading method and a solution blending method. In general, it is preferable to perform ordinary melt-kneading using a Banbury mixer, a Henschel mixer or a kneading roll.

〔Example〕

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Reference Example 1 (mainly production of polystyrene having a syndiotactic structure) To a reaction vessel were added toluene 32 as a reaction solvent, methylaluminoxane as a catalyst component as aluminum atoms at 1335 mmol and tetraethoxytitanium at 13.4 mmol, and then 15 kg of styrene. Was added. At 55 ° C,
The reaction was performed for 2 hours.

After the completion of the reaction, the obtained product was washed with a mixed solution of sodium hydroxide and methanol to decompose and remove the catalyst component. Then, by drying, 2.1 kg of a styrene-based polymer (polystyrene) was obtained. Next, this polymer is
Soxhlet extraction using methyl ethyl ketone as a solvent,
An extraction residue of 95% by weight was obtained. The weight average molecular weight of this extraction residue was 400,000, and the melting point was 270 ° C. In addition, this polymer was analyzed by ¹³ C-NMR (solvent: 1,2-dichlorobenzene) to find that it was found to be 145.35 due to the syndiotactic structure.
Absorption was observed in ppm, and the syndiotacticity in racemic pentad calculated from the peak area was 98%.

Reference Example 2 (Production of maleic anhydride-modified styrene-hydrogenated butadiene-styrene block copolymer) 1 kg of styrene-ethylene / butylene block copolymer (trade name: Clayton G 1650, manufactured by Shell Chemical Company) and 20 g of maleic anhydride And 5 g of dicumyl peroxide were dry-blended at room temperature. Then, using a twin-screw extruder with a co-rotating vent (screw diameter 30 mm, L / D = 22),
After melt-kneading at 0 ° C. and 50 rpm, pelletized,
A maleic anhydride-modified styrene-hydrogenated butadiene-styrene block copolymer was obtained.

After collecting 2 g of the obtained pellet and pulverizing the powder, 100 m
Soxhlet extraction was performed with 1 liter of acetone for 10 hours. Then, the sample was dried under reduced pressure at 60 ° C. for 24 hours to obtain a sample. This sample had a characteristic absorption at 1785 cm ^-1 in the infrared absorption spectrum (IR), and it was confirmed that maleic anhydride was graft-copolymerized.

Examples 1 to 4 (a) Polystyrene mainly having a syndiotactic structure obtained in Reference Example 1, (b) Nylon 66, maleic acid-modified styrene hydrogenated butadiene-styrene block copolymer, and (d) styrene-hydrogen Butadiene-styrene block copolymer was blended in parts by weight shown in Table 1,
The mixture was extruded at 300 ° C. using a twin-screw kneading extruder (inner diameter: 20 mm), pelletized, and then molded using an injection molding machine (trade name: MIN-7, manufactured by Niigata Iron Works Co., Ltd.). The Izod impact strength of this molded product was measured according to JIS-K7110.

The weight change rate (%) after boiling the Izod test piece in boiling water for 8 hours after it was completely immersed in hot water was used as an index of hot water resistance. The Vicat softening point was measured according to JIS-K7206. The results are shown in Table 2.

Example 5 In Example 1, component (b) was replaced with nylon 6, and component (c) was replaced with maleic anhydride-modified styrene obtained in Reference Example 2.
The same operation as in Example 1 was performed, except that the hydrogenated butadiene-styrene block copolymer was used, and the amount was as shown in Table 1. The results are shown in Table 2.

Comparative Examples 1 to 4 The same operation as in Example 1 was performed, except that the compounding amount was changed to the amount shown in Table 1. Second result
It is shown in the table.

[Effects of the Invention] The resin composition of the present invention is mainly blended with a styrene-based polymer having a syndiotactic structure, and has good compatibility between components. It has excellent physical properties such as water resistance and impact strength.

Therefore, the resin composition of the present invention is expected to be widely and effectively used as an industrial material, a material for machine parts, and the like that require heat resistance, water resistance, and various mechanical properties.

Claims (2)

(57) [Claims] (1) 5 to 95% by weight of a styrenic polymer having a syndiotactic structure, (b) 95 to 5% by weight of a polyamide and a total of 100 parts by weight of the components (a) and (b). On the other hand, (c) selected from an AB block copolymer, an A-grafted B copolymer and a B-grafted A copolymer modified by graft polymerization of an unsaturated carboxylic acid or a derivative thereof. 1 to 50 parts by weight of one or more types of block or graft copolymers [where A represents atactic polystyrene and B represents polybutadiene, polyisoprene, hydrogenated polybutadiene and hydrogenated polyisoprene Shows one or more polymers. ] The styrene-type resin composition which has a main component. 2. A total of 100 parts by weight of (a) 5 to 95% by weight of a styrenic polymer having a syndiotactic structure, (b) 95 to 5% by weight of polyamide, and the components (a) and (b). On the other hand, (c) selected from an AB block copolymer, an A-grafted B copolymer and a B-grafted A copolymer modified by graft polymerization of an unsaturated carboxylic acid or a derivative thereof. (D) one or two or more types of block or graft copolymers and (d) an AB block copolymer, an A-grafted B copolymer and a B-grafted A copolymer. One or more blocks or graft copolymers Y
Parts by weight [where A represents atactic polystyrene, and B represents one or more polymers selected from polybutadiene, polyisoprene, hydrogenated polybutadiene and hydrogenated polyisoprene. And X and Y simultaneously satisfy the following relationship: 1 part by weight ≦ X + Y ≦ 50 parts by weight 1 part by weight ≦ X ≦ 50 parts by weight 0 part by weight ≦ Y ≦ 49 parts by weight].