JP2519091B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a thermoplastic resin composition having excellent impact resistance, chemical resistance, and appearance of a molded article.

<Prior Art> Polyamide resins are widely used in mechanical parts, electric / electronic parts, automobile parts, etc. because of their excellent moldability, heat resistance, mechanical strength, chemical resistance, wear resistance, etc. ,
There are problems such as reduced impact resistance in a dry state and dimensional change due to moisture absorption. On the other hand, as typical rubber-reinforced styrene resins, acrylonitrile-butadiene-styrene copolymer (ABS resin), and AES resins and AAS resins in which the rubber component of the ABS resin is replaced with ethylene-propylene rubber or acrylic rubber are also used. It is widely used for automobile parts, electric equipment parts, office equipment parts, etc., and has excellent impact resistance and dimensional stability, but has a problem of relatively poor chemical resistance.

Polyamide and ABS to improve these problems
It has been proposed to melt mix resins (Japanese Patent Publication No. 38-2).
3476), the compatibility of polyamide and ABS resin is poor, and the molded product shows a delaminated state, and only a material having low impact strength can be obtained.

In order to improve the compatibility of polyamide ABS resin,
It has been proposed to introduce / modify a functional group such as carboxylic acid or amide group having reactivity or affinity with polyamide into an ABS resin (JP-A-54-11159, JP-A-58-32656, JP-A-58-32656, JP-A-58-32656). 58-93745) has a problem that the appearance of the molded product is deteriorated and the impact strength is not sufficiently improved by introducing a functional group.

<Problems to be Solved by the Invention> As a result of diligent studies on the improvement of the above-mentioned quality problems of the composition comprising a polyamide resin and a rubber-reinforced styrene-based resin, the present inventors have found that the polyamide and the rubber-reinforced styrene-based resin The present inventors have found that a material excellent in impact resistance, chemical resistance and appearance of a molded article can be obtained by mixing a resin and a specific modified graft copolymer in a specific ratio, and arrived at the present invention.

<Means for Solving Problems> That is, the present invention provides (A) polyamide, (B) rubber-reinforced styrene resin and (C) polyethylene, polypropylene, polybutene,
Aromatic vinyl monomer in the presence of a polyolefin selected from polyisobutylene and poly 4-methylpentene 50
Copolymerize a monomer mixture consisting of ˜99.9% by weight, 0.1 to 30% by weight of a monomer having reactivity or affinity for polyamide and 0 to 49.9% by weight of other copolymerizable vinyl monomer. (A), which comprises a modified graft copolymer
Assuming that the total amount of (B) and (C) is 100 parts by weight,
(A) 90 to 10 parts by weight, (B) 5 to 85 parts by weight and (C)
5 to 85 parts by weight, and the rubber content in the composition is 5 to 5 parts by weight.
The present invention provides a thermoplastic resin composition having an excellent impact resistance, chemical resistance and appearance of a molded article, which is characterized by being 40% by weight.

 Hereinafter, the present invention will be described in detail.

Examples of the polyamide (A) used in the present invention include ethylenediamine, diaminobutane, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine,
2,2,4- and 2,4,4-trimethylhexamethylenediamine, 1,3 and 1,4-bis (aminomethyl) cyclohexane, bis (P-aminocyclohexyl) methane, meta-xylylenediamine, para-xylylenediene Polyamides derived from aliphatic, alicyclic and aromatic diamines such as amines and aliphatic, alicyclic and aromatic dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid and isophthalic acid A polyamide obtained by ring-opening polymerization of lactams such as ξ-caprolactam and ω-dodecalactam, 6-aminocaproic acid,
Examples thereof include polyamides derived from 11-aminoundecanoic acid, 12-aminododecanoic acid and the like, copolyamides of these, and mixed polyamides.

Polycaproamide (nylon 6), polydodecaamide (nylon 12), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 6) in the sense that they are industrially manufactured inexpensively and in large quantities.
6), polyhexamethylene sebacamide (nylon 610),
And copolymers thereof, such as nylon 6/66 (the "/" mark means copolymer), nylon 6/610,
Nylon 6/12, nylon 66/12, nylon 6/66/610/12,
And mixtures thereof are useful. Also, bis (p-aminocyclohexyl) methane / terephtyl acid /
Isophthalic acid-based polyamides are also useful.

There is no limitation on the degree of polymerization of the polyamide used, and polyamides with a relative viscosity of concentrated sulfuric acid (polymer 1 g dissolved in 100 ml of 98% concentrated sulfuric acid, measured at 25 ° C, the same applies below) within the range of 1.8 to 6.0 It can be arbitrarily selected.

The molecular structure of polyamide is also not limited, and linear polyamide, branched polyamide, or the like may be used. A linear polyamide is produced by an ordinary method, but a branched polyamide is a branching agent having three or more functional groups capable of forming a polyamide in a raw material, such as bis (ω-aminohexyl) amine, diethylenetriamine, trimesic acid, and bislactam. Is added in a small amount to polymerize.

In Nylon-6, the ratio of the terminal amino group to the terminal carboxyl group is not particularly limited and any one can be used.

As a polymerization method, a melt polymerization, an interfacial polymerization, a solution polymerization, a bulk polymerization, a solid phase polymerization and a method combining these methods are used, and in general, the melt polymerization is most suitable. Further, particularly when the polyamide raw material is a lactam, a polymer may be obtained by anionic polymerization.

The rubber-reinforced styrene resin (B) in the present invention is
50-100% by weight of aromatic vinyl monomer and 0-50% by weight of other copolymerizable vinyl monomer in the presence of rubbery polymer
A graft copolymer obtained by polymerizing a monomer mixture consisting of or such a graft copolymer, and an aromatic vinyl monomer 50 to 10
It is a mixture with 0% by weight and a styrene-based polymer consisting of 0 to 50% by weight of another copolymerizable vinyl monomer. The rubber-like polymer used in the graft copolymer includes polybutadiene and butadiene-styrene copolymer. Polymer,
Non-diene rubbers such as butadiene-acrylonitrile copolymers and other diene rubber-like polymers and ethylene-propylene copolymers, ethylene-propylene-non-conjugated diene copolymers, acrylic rubber-like polymers and chlorinated polyethylene Polymers are exemplified, and they can be used alone or in combination of two or more. These rubbery polymers are produced by emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization and the like.

There are no particular restrictions on the particle size and gel content of the rubber-like polymer when it is produced by emulsion polymerization, or the average particle size is 0.1 to 1 μm and the gel content is 0 to 95.
% Is preferable.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, t-butylstyrene, α-methylvinyltoluene, dimethylstyrene, chlorostyrene,
Examples thereof include dichlorostyrene, bromostyrene, and dibromostyrene, which can be used alone or in combination of two or more.

Other vinyl monomers copolymerizable with the aromatic vinyl monomer include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate. Unsaturated carboxylic acid alkyl esters such as ethyl methacrylate, propyl methacrylate and 2-ethylhexyl methacrylate, maleimide, N-phenylmaleimide, N-methylmaleimide, N-cyclohexylmaleimide and the like maleimide compounds are exemplified alone or in combination of two or more. It can be mixed and used.

The ratio of the rubbery polymer and the monomer mixture in the graft copolymer is not particularly limited, but the rubbery polymer 20 to 80
% By weight and 80 to 20% by weight of the monomer mixture.

The graft ratio of the graft copolymer is not particularly limited, but is preferably 20 to 100%.

As the graft polymerization method, known emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization or a combination thereof may be used.

The aromatic vinyl monomer constituting the styrene-based polymer used by mixing with the graft copolymer and the other copolymerizable vinyl monomer are the monomers used in the graft copolymer, respectively. Any one kind or two or more kinds can be selected and used from the same group. There is no particular limitation on the molecular weight of the styrene polymer, but the weight average molecular weight is 1
It is preferable that it is from 000 to 1,000,000. As a method for polymerizing the styrene-based polymer, known emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization or a combination thereof may be used.

The modified graft copolymer (C) used in the present invention means an aromatic vinyl monomer in the presence of a polyolefin.
Copolymerizing a monomer mixture consisting of 99.9% by weight, 0.1 to 30% by weight of a monomer having reactivity or affinity for polyamide and 0 to 49.9% by weight of another copolymerizable vinyl monomer. Is a polymer.

The polyolefin constituting the modified graft copolymer is a polymer selected from polyethylene, polypropylene, polybutene, polyisobutylene and poly-4-methylpentene-1.

As the aromatic vinyl monomer, any one kind or two or more kinds selected from the same group as the aromatic vinyl monomer used for the rubber-reinforced styrene resin (B) can be selected and used.

The monomer having reactivity or affinity for polyamide is a vinyl monomer having a functional group that reacts with or has affinity for a carboxylic acid group or amino group at the terminal of polyamide, and specifically, Examples thereof include vinyl monomers having a functional group such as a carboxylic acid group, an acid anhydride group, an amino group, an epoxy group, and a hydroxyl group, and one kind or two or more kinds can be used.

Examples of the vinyl monomer having a carboxylic acid group include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid, and one or more kinds thereof can be used. Examples of the vinyl monomer having an acid anhydride group include maleic anhydride, citraconic anhydride, chloromaleic anhydride, and the like, and one or more of them can be used.

As the vinyl monomer having an amino group, acrylamide, methacrylamide, aminoethyl acrylate,
Examples thereof include dimethylaminoethyl methacrylate and diethylamino methacrylate, and one kind or two or more kinds may be used. Examples of the vinyl monomer having an epoxy group include glycidyl acrylate and glycidyl methacrylate, and one or two or more of them can be used.

Examples of the vinyl monomer having a hydroxyl group include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and the like, and one kind or two or more kinds can be used.

As the other copolymerizable vinyl monomer, any one kind or two or more kinds are selected from the same group as the other copolymerizable vinyl monomer used for the rubber-reinforced styrene resin (B). Can be used.

The weight ratio of the aromatic vinyl monomer, the monomer having reactivity or affinity for polyamide and the other copolymerizable vinyl monomer is 50 to 99.9% by weight, 0.1 to 30% by weight and 0 to 49.9% by weight, respectively. % By weight. Outside this range, the desired composition cannot be obtained.

Preferably, 60 to 90% by weight of aromatic vinyl monomer, 0.5 to 2 monomer having reactivity or affinity with polyamide.
0% by weight and 0 to 35% by weight of the copolymerizable monomer.

Further, the composition ratio of the polyolefin and the monomer mixture constituting the modified graft copolymer is not particularly limited, but from the viewpoint of physical properties of the final composition, the polyolefin is 5 to 95% by weight and the monomer mixture is 95 to 5%. % By weight is preferred, especially 10-70% by weight of polyolefin and 90-30% by weight of the monomer mixture.

As a method for producing the modified graft copolymer, known emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, or a combination thereof can be employed.

The thermoplastic resin composition of the present invention comprises the above-mentioned polyamide (A), rubber-reinforced styrene-based resin (B) and modified graft copolymer (C).
Assuming that the total amount of (B) and (C) is 100 parts by weight,
(A) 90 to 10 parts by weight, (B) 5 to 85 parts by weight and (C)
5 to 85 parts by weight, and the rubber content in the composition (the ratio of the rubber derived from the rubber-reinforced styrenic resin to the composition) is 5 to 40% by weight.

When the composition ratio of (A), (B) and (C) is out of the above range, the impact resistance, the chemical resistance and the appearance of the molded product are poor.

Preferably, (A) 80 to 20 parts by weight, (B) 10 to 70 parts by weight and (C) 10 to 70 parts by weight, and the rubber content is 10
~ 30% by weight.

Further, if the rubber content in the composition is less than 5% by weight, the impact strength is inferior, and if it exceeds 40% by weight, the rigidity and hardness decrease, which is not preferable.

There is no limitation on the mixing order of the polyamide (A), the rubber-reinforced styrene resin (B) and the modified graft copolymer (C), and the three components are mixed at once, and the remaining one component is mixed after premixing the two components. be able to. Further, the mixing method is not limited at all, and a known method such as a Banbury mixer, a roll or an extruder can be adopted.

At the time of mixing, if necessary, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a lubricant, a dye, a pigment, a plasticizer, a flame retardant, a release agent, a glass fiber, a metal fiber, a carbon fiber, Additives such as metal flakes, auxiliary materials and fillers can be added. Also, polyacetal, polycarbonate, polybutylene terephthalate, polyethylene terephthalate,
A thermoplastic resin such as polyphenylene oxide, polymethylmethacrylate, or polyvinyl chloride can also be appropriately mixed.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples. The numbers of parts and percentages are shown on a weight basis.

Reference Example 1 Production of Rubber Reinforced Thermoplastic Resin (B) B-1 15 parts of acrylonitrile by an emulsion polymerization method in the presence of 50 parts (solid content) of polybutadiene latex having an average particle size of 0.45 μm and a gel content of 83%. An ABS graft copolymer latex was prepared by copolymerizing 35 parts of styrene.

B-2 AAS graft copolymer latex is prepared by copolymerizing 15 parts of acrylonitrile and 35 parts of styrene by emulsion polymerization in the presence of 50 parts (solid content) of crosslinked polybutyl acrylate latex having an average particle size of 0.3μ. did.

B-3 Iodine number 15.3, Mooney viscosity 67, propylene content 50%, EPDM 75 parts containing ethylidene norbornene as a diene component is dissolved in n-hexane 1000 parts and ethylene dichloride 650 parts to prepare styrene 75 parts and acrylonitrile 25 parts. And 3 parts of benzoyl peroxide were added, and the temperature was 67 ° C, 10
Polymerization was performed under a nitrogen atmosphere for an hour to prepare an AES graft copolymer solution.

The graft copolymers B-1 and B-2 were salted out with calcium chloride, separated and dried. The graft copolymer B-3 was recovered by introducing the polymerization solution into a large excess of methanol and separating and drying the deposited precipitate.

The amount of rubber contained in the graft copolymers B-1, B-2 and B-3 was measured by infrared spectroscopy and found to be about 50% in all cases.

Reference Example 2 Production of Modified Graft Copolymer (C) Granular polypropylene was dispersed in water, styrene, acrylonitrile, and methacrylic acid or glycidyl methacrylate were added and polymerized under a radical polymerization catalyst to prepare modified graft copolymers C-1 to C-3. Created.

The composition obtained by infrared spectroscopy is shown in Table-1.

Example Polyamide (A), rubber-reinforced styrenic resin (B) produced in Reference Example and modified graft copolymer (C) were mixed in the proportions shown in Table 2 and a twin-screw extruder having a diameter of 40 mm was used.
The mixture was melt mixed and granulated at 250 ° C. In addition, nylon 6 (concentrated sulfuric acid relative viscosity 2.6) as polyamide and acrylonitrile-styrene copolymer (AS) beads of intrinsic viscosity (dimethylformamide solution, measured at 30 ° C.) 0.60 by a suspension polymerization method, Each was used.

The physical properties of the obtained resin composition were measured by the following methods, and the results are shown in Table 2.

Impact strength (Izod with notch) ASTM D-256 (23 ℃) Appearance of molded product: A molded product of 150 mm × 150 mm × 3.18 mm was molded, and its appearance (presence of flow marks) was visually evaluated.
Further, the same molded product was visually judged by a cross-cut test using an adhesive tape for the presence or absence of delamination.

Chemical resistance: A molded product of 150 mm × 20 mm × 3 mm was fixed to a cantilever jig, subjected to a deflection of 30 mm, and then immersed in various chemicals for 24 hours to determine the presence or absence of cracks.

The above test pieces for quality evaluation were molded using a 3.5 oz injection molding machine with the cylinder temperature set to 250 ° C.

<Example 1 and Comparative Example 1> As shown in Table 2, the effect of blending the modified graft copolymer with the polyamide / ABS composition is shown.

<Examples 2 to 3> Examples in which AAS or AES is used as the rubber-reinforced styrene resin will be shown.

<Examples 4 to 5 and Comparative Examples 2 to 3> Polyamide (A), rubber-reinforced styrene resin (B),
The influence of the blending ratio of the modified graft copolymer (C) and the amount of rubber in the composition on the quality is shown.

<Examples 6 to 7 and Comparative Example 4> The influence of the composition of the modified graft copolymer (C) on the quality is shown.

<Effects of the Invention> The thermoplastic resin composition of the present invention is a composition excellent in impact resistance, chemical resistance, and appearance of a molded product, as compared with conventional polyamide resin compositions.

Claims (1)

(57) [Claims] 1. An aromatic vinyl in the presence of (A) polyamide, (B) rubber-reinforced styrene resin and (C) a polyolefin selected from polyethylene, polypropylene, polybutene, polyisobutylene and poly-4-methylpentene-1. Monomer
Copolymerization of a monomer mixture consisting of 50 to 99.9% by weight, 0.1 to 30% by weight of a monomer having reactivity or affinity for polyamide, and 0 to 49.9% by weight of another copolymerizable vinyl monomer. Which comprises a modified graft copolymer (A),
Assuming that the total amount of (B) and (C) is 100 parts by weight,
(A) 90 to 10 parts by weight, (B) 5 to 85 parts by weight and (C)
5 to 85 parts by weight, and the rubber content in the composition is 5 to 5 parts by weight.
The thermoplastic resin composition is 40% by weight.