JP2001152011A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition excellent in fluidity and capable of providing a molded product excellent in mechanical strengths. SOLUTION: This thermoplastic resin composition comprises (A) 0.1-80 wt.% styrenic resin, (B) 10-90 wt.% polyamide having 1.8-2.5 relative viscosity (obtained by dissolving 1 g resin in 100 mL 98%-sulfuric acid and measuring the viscosity at 25 deg.C), (C) 1-60 wt.% rubber-reinforced styrenic copolymer containing a carboxy group-containing unsaturated compound copolymerized therewith, and (D) 2-90 pts.wt. carbon fiber having <=0.7 mm weight average fiber length based on 100 pts.wt. total of the components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic resin composition having excellent fluidity and capable of obtaining a molded article having excellent mechanical strength such as elastic modulus.

[0002]

2. Description of the Related Art
In order to increase the modulus of elasticity of a molded product obtained from a thermoplastic resin, a method of adding a filler such as carbon fiber, glass fiber, talc, and mica has been adopted. Among these fillers, carbon fiber has a very high elastic modulus itself,
It is used as the most effective means because the effect of improving the elastic modulus by addition is large.

However, in the case of an amorphous resin such as a styrene resin, the addition of carbon fiber improves the elastic modulus,
The impact strength is low and the material becomes brittle. In particular, many molded products (products) made of a material requiring high rigidity are thin-walled.

In the case of a crystalline resin such as nylon, the impact strength is small even when carbon fiber is blended, but the nylon itself has a problem that the elastic modulus is reduced and the dimensional change is large due to water absorption. Furthermore, since it is a crystalline resin, the molding shrinkage is large, and in particular, when reinforced with a fibrous filler such as carbon fiber, there is a problem that warping due to anisotropy of the shrinkage occurs. In addition, when carbon fibers are mixed with the resin, there is another problem that the fluidity is extremely reduced and the moldability is deteriorated.

JP-A-1-170635 discloses a thermoplastic resin composition containing a rubber-reinforced styrene-based copolymer resin, a styrene-based resin, a polyamide-based polymer, and the like. It is described that it can be blended. However, the present invention is intended to achieve the effect of the combination of the three components, and there is no example in which the inorganic fibers are blended in the examples. Naturally, the solution to the problem when the inorganic fibers are blended is as follows. Nothing is shown.

[0006] An object of the present invention is to provide a thermoplastic resin composition capable of obtaining a molded article having excellent mechanical strength such as elastic modulus without deteriorating moldability due to good fluidity.

[0007]

The present invention provides (A) 0.1 to 80% by weight of a styrene resin and (B) a relative viscosity (1 g is dissolved in 100 ml of 98% sulfuric acid and measured at 25 ° C.)
A rubber-reinforced styrene-based copolymer in which 10 to 90% by weight of a polyamide of 1.8 to 2.5 and (C) a carboxyl group-containing unsaturated compound are copolymerized,
(D) Carbon fiber having a weight average fiber length of 0.7 mm or less
Provided is a thermoplastic resin composition containing 2 to 90 parts by weight based on a total of 100 parts by weight of (A) and (B).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the styrene resin of the component (A) used in the present invention, a homopolymer of an aromatic vinyl monomer, an aromatic vinyl monomer and a maleimide monomer, and a vinylcyan monomer And at least one selected from copolymers with a copolymer or another copolymerizable vinyl monomer and a rubber-modified styrene resin.

As the aromatic vinyl monomer, styrene,
Alkyl-substituted styrene such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-t-butylstyrene, 2,4-dimethylstyrene, α-methylstyrene, α-methyl-4- Examples thereof include α-alkyl-substituted styrenes such as methylstyrene, halogenated styrenes such as 2-chlorostyrene and 4-chlorostyrene, and vinylnaphthalene, among which styrene is preferable.

The maleimide-based monomers include maleimide, N-methylmaleimide, N-ethylmaleimide,
-Phenylmaleimide, N-cyclohexylmaleimide, etc., of which N-phenylmaleimide and N-cyclohexylmaleimide are preferred.

Examples of the vinylcyan monomer include acrylonitrile and methacrylonitrile, and acrylonitrile is preferred.

Other copolymerizable vinyl monomers include (C1-C10) alkyl (meth) acrylates,
(Meth) acrylate monomers such as hydroxyl-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; and (meth) acrylate monomers such as glycidyl (meth) acrylate; Examples include carboxyl group-containing monomers such as acrylic acid, maleic anhydride, maleic acid, itaconic anhydride, and citraconic anhydride.

The rubber-modified styrenic resin includes (i) a graft copolymer of a rubber component obtained by polymerizing at least an aromatic vinyl monomer in the presence of a rubber component and an aromatic vinyl monomer ( (Ii) a block copolymer (ABA type block copolymer) of a rubber block and an aromatic vinyl polymer block. Such a block copolymer may be linear or star (star-shaped) and may form a thermoplastic elastomer; (iii) selected from a mixture of a rubber component and a non-rubber modified styrene resin. One or more types may be mentioned. The graft ratio of the monomer to be grafted to the rubber component is preferably 30% by weight or more, more preferably 40% by weight or more, and further preferably 50 to 150%.
% By weight.

The rubber component contained in the rubber-modified styrene resin includes butadiene rubber, butadiene-isoprene rubber, butadiene-acrylonitrile rubber, ethylene-
One or more selected from non-styrene rubbers such as propylene rubber, isoprene rubber, acrylic rubber, and ethylene-vinyl acetate rubber, and styrene rubbers such as styrene-butadiene rubber and styrene-isoprene rubber. In addition,
The butadiene rubber may be a high cis type having a high content of the cis-1,4 structure or a low cis type having a low content of the cis-1,4 structure. ５5 μm is preferred.

As the styrene resin of the component (A), polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin), acrylonitrile-butadiene rubber-methacrylic Methyl acid-styrene copolymer (ABSM resin), acrylonitrile-styrene copolymer (AS resin), styrene-methacrylate copolymer (MS resin), high-impact polystyrene (HIPS), acrylonitrile-n-butyl acrylate rubber Examples include a styrene copolymer (AAS resin) and a styrene-butadiene copolymer (SBS resin).

The content of the component (A) is 0.1 to 80% by weight, preferably 0.1 to 80% by weight based on the total amount of the components (A) to (C).
-60% by weight, more preferably 5-50% by weight.

As the polyamide of the component (B) used in the present invention, a polyamide resin formed from a diamine and a dicarboxylic acid and a copolymer thereof, for example, nylon 6
6. Polyhexamethylene sebacamide (nylon 61
0), polyhexamethylene dodecamide (nylon 61
2), polydodecamethylene dodecanamid (nylon 12
12), polymethaxylylene adipamide (nylon MX
D6), polytetramethylene adipamide (nylon 4
6) and mixtures and copolymers thereof; nylon 6/6
Nylon 66/6 having a content of 6,6T of 50 mol% or less
T (6T: polyhexamethylene terephthalamide), 6I
Nylon 66 / 6I (6
I: polyhexamethylene isophthalamide), nylon 6
Copolymers such as T / 6I / 66 and nylon 6T / 6I / 610; polyhexamethylene terephthalamide (nylon 6T), polyhexamethylene isophthalamide (nylon 6I), poly (2-methylpentamethylene) terephthalamide (nylon M5T) ), Aromatic polyamide resins such as poly (2-methylpentamethylene) isophthalamide (nylon M5I), nylon 6T / 6I, nylon 6T /
One or more selected from copolymers such as M5T are exemplified.

The polyamide of the component (B) includes:
Ring-opening polymers of cyclic lactams, polycondensates of aminocarboxylic acids and copolymers of these components, for example, nylon 6, poly-ω-undecanamide (nylon 11), poly-ω-dodecanamide (nylon 12) and the like Aliphatic polyamide resins and their copolymers; copolymers of polyamides comprising diamines and dicarboxylic acids, for example, nylon 6T / 6, nylon 6T / 11, nylon 6T / 1
2, nylon 6T / 6I / 12, nylon 6T / 6I /
610/12.

The polyamide of the component (B) has a relative viscosity (1).
g was dissolved in 100 ml of 98% sulfuric acid and the value was measured at 25 ° C) of 1.8 to 2.5. When the relative viscosity is 1.8 or more, the impact resistance of the molded product is improved. 1. The relative viscosity is 2.
When it is 5 or less, it is possible to prevent the moldability from deteriorating due to the decrease in fluidity, and it is particularly effective when carbon fibers are blended.

The content of the component (B) is from 10 to 90% by weight, preferably from 30 to 80% by weight, more preferably from 50 to 50% by weight, based on the total amount of the components (A) to (C) in order to enhance the impact resistance.
~ 80% by weight.

The rubber-reinforced styrene copolymer obtained by copolymerizing the carboxyl group-containing unsaturated compound of the component (C) used in the present invention is a component for enhancing the compatibility between the components (A) and (B). is there.

The styrene copolymer as the component (C) is obtained by polymerizing a carboxyl group-containing unsaturated compound and, if necessary, other monomers copolymerizable therewith in the presence of a rubbery polymer. The following are mentioned.

A monomer containing aromatic vinyl as an essential component or an aromatic vinyl and a carboxyl group-containing unsaturated compound as essential components in the presence of a rubbery polymer obtained by copolymerizing a carboxyl group-containing unsaturated compound. Graft polymer obtained by polymerizing monomers Graft polymer obtained by copolymerizing monomers containing aromatic vinyl and a carboxyl group-containing unsaturated compound as essential components in the presence of a rubbery polymer Copolymer A mixture of a rubber-reinforced styrene resin in which a carboxyl group-containing unsaturated compound is not copolymerized, a carboxyl group-containing unsaturated compound, and a copolymer of a monomer having an aromatic vinyl as an essential component. In the above-mentioned mixture of a carboxyl group-containing unsaturated compound and a copolymer having an aromatic vinyl as an essential component, and a mixture of a copolymer having an aromatic vinyl as an essential component, Styrene is preferred as the aromatic vinyl, and acrylonitrile is preferred as the monomer copolymerized with the aromatic vinyl.

The content of the carboxyl group-containing unsaturated compound in the styrene copolymer of the component (C) is preferably 0.1 to 8% by weight, more preferably 0.2 to 7% by weight.

The content of the component (C) is 1 to 60% by weight, preferably 5 to 40% by weight, more preferably 5 to 30% by weight, based on the total amount of the components (A) to (C).

The component (D) carbon fiber used in the present invention comprises:
Examples thereof include cellulose-based, PAN-based, and pitch-based carbon fibers. The weight-average fiber length is 0.7 mm or less, and preferably 0.1 to 0.5 mm, in order to enhance the fluidity of the composition.

The carbon fiber as the component (D) has a weight average fiber length of 0.1 to 0.1 to further improve the fluidity of the composition.
The content ratio of those having a diameter of 4 mm is preferably 30 to 95% by weight, and more preferably 50 to 95% by weight.

The content of the component (D) is 2 to 90 parts by weight, preferably 10 to 60 parts by weight, more preferably 10 to 50 parts by weight based on 100 parts by weight of the total of the components (A) to (C).
Parts by weight.

The composition of the present invention may contain, if necessary, a flame retardant (eg, a bromo flame retardant, a chlorine flame retardant, a phosphorus flame retardant, an inorganic flame retardant such as antimony trioxide), heat, light, oxygen, or the like. (Antioxidants such as phenolic compounds and phosphorus compounds; ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds and phenyl salicylate compounds); hindered amine stabilizers and heat stabilizers such as tin compounds and epoxy compounds ), A plasticizer, a slidability improving agent such as dimethylpolysiloxane, a lubricant, a release agent, an antistatic agent, a coloring agent, and the like.

The thermoplastic resin composition of the present invention can be used to obtain molded articles by various molding methods such as extrusion molding and injection molding, and the molded articles are suitable for housings and parts of home appliances and OA equipment. .

[0031]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. (A) component ABS resin: styrene content 45%, acrylonitrile content 1
5%, rubber amount 40% (B) component Nylon 6-A: relative viscosity 2.1 Nylon 6-B: relative viscosity 3.1 (C) component Maleic acid-modified ABS resin; styrene content 42%, acrylonitrile content 15% , Rubber content 40%, maleic acid content 3% (D) component carbon fiber; Besphite HTA-C6-NR (diameter 7 μm, fiber length 6 mm) Examples 1-2, Comparative Examples 1-7 Each component shown in Table 1 [The components (A) to (C) are weight%,
The component (D) is expressed in parts by weight based on the components (A) to (C)]
And melt-kneaded with a twin-screw extruder to obtain a pellet-shaped resin composition. The extrusion temperature is 250 ° C,
The carbon fiber was introduced from a side feeder, and the carbon fiber length was adjusted by a screw operation of an extruder. Using these compositions, the respective measurements shown in Table 1 were performed by the following methods. (Length of carbon fiber) The carbon fiber was taken out by dissolving the resin composition in the form of a pellet with a solvent, taking an optical microscope photograph, measuring 1,000 carbon fiber lengths based on the photograph, and calculating the weight average fiber length. . In addition, 1000 measured by this method
For the book, the ratio (% by weight) of the fiber having a weight average fiber length of 0.1 to 0.4 mm in the whole was determined. (Bending elastic modulus, Izod impact strength, warpage) Using an injection molding machine (cylinder temperature 250 ° C, mold temperature 60 ° C; 265 / 100MSII manufactured by Mitsubishi Heavy Industries, Ltd.), perform a bending test from a pellet-shaped resin composition. A 1/4 inch thick test piece, a notched 1/4 inch test piece for Izod testing,
120mm x 120mm x for evaluation of warpage (dimensional stability)
A 2 mm flat plate was prepared. ASTM for bending test
D790, Izod impact test is ASTM D256
, And use a height gauge for the amount of sled.
It was measured at 3 ° C. and 50% RH. (Fluidity) Fluidity is evaluated by melt index, and AS
Compliant with TM D1238. The measurement was performed at 250 ° C., and the total weight of the weight and the piston was 10 kg.

[0032]

[Table 1]

As is clear from Examples 1 and 2,
The composition containing the component (D) having a predetermined fiber length together with the components (A) to (C) has excellent mechanical properties, small warpage, and good dimensional stability. Furthermore, since the fluidity was good, the moldability was good, and almost no burrs were generated in the obtained molded product.

As apparent from Comparative Example 2, (A) to
The composition containing the component (C) but not the carbon fiber of the component (D) had an extremely high Izod impact strength but a very low flexural modulus. Further, as is clear from Comparative Example 5, the composition containing the components (A) to (C) and having a carbon fiber length of 0.89 mm has poor moldability due to poor fluidity. The burrs also increased in the molded product, and a great deal of labor was required for post-processing for finishing.

[0035]

The thermoplastic resin composition of the present invention comprises (A)
Due to the combination of (D) to (D), mechanical strength such as flexural modulus and impact resistance is excellent, and the molded product does not deform and has good dimensional stability. Further, since (D) carbon fiber having a predetermined fiber length is blended, the fluidity is excellent, and as a result, the moldability is excellent, so that a thin product having excellent mechanical strength can be easily produced. .

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4J002 AC08W BC01W BC03W BC04W BC05W BC06W BC08W BC09W BC11W BG01W BG04W BG05W BG10W BH01W BH02W BN13Y BN14W BN14Y BN15W CL01X CL03X DA016 FA046

Claims (2)

[Claims] 1. (A) 0.1 to 80% by weight of a styrene resin, and (B) a relative viscosity of 1.8 to 2.5 (measured at 25 ° C. by dissolving 1 g of 98% sulfuric acid in 100 ml of sulfuric acid). 10 to 90% by weight of a polyamide and (C) 1 to 60% by weight of a rubber-reinforced styrene copolymer obtained by copolymerizing a carboxyl group-containing unsaturated compound, and (D) a weight average fiber length of 0.7%.
A thermoplastic resin composition containing 2 to 90 parts by weight based on 100 parts by weight of carbon fibers (A) to (C) having a size of not more than mm. 2. Component (D) having a weight average fiber length of 0.1 to
The thermoplastic resin composition according to claim 1, wherein the content of 0.4 mm carbon fibers is 30 to 95% by weight.