JP2001181516A - Thermoplastic resin composition and its molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition which has a good flowability and gives a molded article excellent in rigidity. SOLUTION: This resin composition contains (A) a thermoplastic resin, (B) a fibrous inorganic filler, and (C) a liquid crystal polymer and has an MI (at 260 deg.C under a load of 5 kg) of 1-500 g/10 min and a flexural strength (with a 1/16 in test specimen) of 6,000-50,000 MPa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition having good fluidity and excellent rigidity of a molded article, and particularly suitable for producing a thin molded article, and a molded article thereof.

[0002]

2. Description of the Related Art
In order to increase the rigidity of a thermoplastic resin, a method of adding an inorganic filler such as carbon fiber, glass fiber, whisker, talc, and mica has been used. When such an inorganic filler is blended, the rigidity can be improved in accordance with the blending amount, but there is a problem that the fluidity is reduced. Therefore, the addition of a certain amount or more of the inorganic filler is not practical because it causes problems such as short shots during molding, and a high-rigidity thermoplastic material excellent in moldability has not been obtained.

Further, Japanese Patent Application Laid-Open No. 7-74301, 8-
No. 170024, 11-12428, by combining a thermoplastic resin and a liquid crystal polymer,
A resin composition having improved fluidity and mechanical strength is disclosed. However, in these prior arts, the inorganic filler such as carbon fiber and glass fiber is an optional component, and there is no specific disclosure about improvement of fluidity and rigidity when the inorganic filler is used in combination.

[0004] It is an object of the present invention to provide a thermoplastic resin composition which is excellent in fluidity and provides a molded article having excellent rigidity.

[0005]

The present invention comprises (A) a thermoplastic resin, (B) a fibrous inorganic filler and (C) a liquid crystal polymer, and has an MI of 260 ° C., a load of 5 kg and a load of 1-500.
Provided is a thermoplastic resin composition having a flexural strength of 20,000 to 50,000 MPa in g / 10 minutes and a 1/16 inch test piece.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermoplastic resin (A) used in the present invention includes polyamide resins, polystyrene resins, polyester resins, polycarbonate resins, and the like.
One or more selected from the group consisting of polyolefin resins, polyurethane resins, polyether resins, polyester ether resins, polyamide ether resins, and polyphenylene oxide resins.

As the component (A), among these, a polyamide resin, a polystyrene resin, a polyester resin, a polycarbonate resin, and a polyolefin resin are preferable, and a combination of a polyamide resin and a polystyrene resin (particularly, an ABS resin) is preferable. A combination of a polycarbonate resin and a styrene resin (particularly an ABS resin) is more preferable.

As the polyamide resin, polyamide resins formed from diamine and dicarboxylic acid and copolymers thereof, specifically, nylon 66, polyhexamethylene sebacamide (nylon 610), polyhexamethylene Dodecanamide (nylon 6.12), polydodecamethylene dodecanamide (nylon 1212), polymethaxylylene adipamide (nylon MXD6), polytetramethylene adipamide (nylon 46), and mixtures and copolymers thereof Nylon 6/66, Nylon 66 / 6T (6T: polyhexamethylene terephthalamide) with a 6T component of 50 mol% or less, and Nylon 66 / 6I (6I: polyhexamethylene isolate) with a 6I component of 50 mol% or less; Phthalamide), nylon 6T / 6I / 66, nylon 6T / 6I / 61 Copolymer and the like; polyhexamethylene terephthalamide (nylon 6T), polyhexamethylene isophthalamide (nylon 6I), poly (2-methyl pentamethylene) terephthalamide (nylon M5
T), copolymers such as poly (2-methylpentamethylene) isophthalamide (nylon M5I), nylon 6T / 6I, nylon 6T / M5T, and copolymer nylon such as amorphous nylon, and amorphous nylon. Examples include polycondensates of terephthalic acid and trimethylhexamethylenediamine.

Further, ring-opened polymers of cyclic lactams, polycondensates of aminocarboxylic acids and copolymers of these components, specifically, nylon 6, poly-ω-undecanamide (nylon 11), poly- Aliphatic polyamide resins such as ω-dodecanamide (nylon 12) and copolymers thereof, copolymers with polyamides comprising diamines and dicarboxylic acids, specifically nylon 6T / 6, nylon 6T
/ 11, nylon 6T / 12, nylon 6T / 6I / 1
2, nylon 6T / 6I / 610/12 and the like, and mixtures thereof.

Examples of the polycarbonate resin include those obtained by reacting a dihydric phenol with a carbonate precursor by a well-known solution method or melting method.

Dihydric phenols are 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2 -Screw (4
-Hydroxy-3,5-dimethylphenyl) propane,
2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3-
Methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl)
One or more selected from sulfones and the like are included. Of these, bis (4-hydroxyphenyl) alkane-based ones are preferred, and bisphenol A is particularly preferred.

The carbonate precursor is at least one selected from diallyl carbonates such as diphenyl carbonate, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, carbonyl halides such as phosgene, and haloformates such as dihaloformate of dihydric phenol.

Although the number average molecular weight of the polycarbonate resin is not particularly limited, it is preferably in the range of about 17000 to 32,000 in order to impart practically required mechanical strength to a molded article obtained from the composition. preferable.

Examples of the polystyrene resin include polymers of styrene and styrene derivatives such as α-substituted and nuclear-substituted styrene. Further, a copolymer mainly composed of these monomers and a monomer of a vinyl compound such as acrylonitrile, acrylic acid and methacrylic acid and / or a conjugated diene compound such as butadiene and isoprene is also included. For example, polystyrene, impact-resistant polystyrene (HIPS) resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, acrylonitrile-styrene copolymer (AS resin), styrene-methacrylate copolymer (MS resin), styrene-butadiene Copolymers (SBS resin) and the like can be mentioned.

Further, the polystyrene resin may include a styrene copolymer in which a carboxyl group-containing unsaturated compound for improving compatibility with the polyamide resin is copolymerized. The styrenic copolymer in which the carboxyl group-containing unsaturated compound is copolymerized is a carboxyl group-containing unsaturated compound and optionally other monomers copolymerizable therewith in the presence of the rubbery polymer. Is a copolymer obtained by polymerizing Specific examples of the components include: 1) In the presence of a rubbery polymer obtained by copolymerizing a carboxyl group-containing unsaturated compound, a monomer containing an aromatic vinyl monomer as an essential component or aromatic vinyl and a carboxyl group-containing unsaturated compound. A graft polymer obtained by polymerizing a monomer containing a saturated compound as an essential component, and 2) a graft polymer containing an aromatic vinyl and a carboxyl group-containing unsaturated compound as essential components in the presence of a rubbery polymer. Graft copolymer obtained by copolymerization of a monomer, 3) a rubber-reinforced styrene resin in which a carboxyl group-containing unsaturated compound is not copolymerized, a carboxyl group-containing unsaturated compound, and aromatic vinyl as essential components. 4) A mixture of the above 1) and 2) and a copolymer containing a carboxyl group-containing unsaturated compound and aromatic vinyl as essential components; 5) The above 1) and 2) ), 3), 4) and aromatic vinyl There is a mixture with a copolymer as an essential component.

In the above 1) to 5), styrene is preferable as the aromatic vinyl, and acrylonitrile is preferable as the monomer copolymerized with the aromatic vinyl. The content of the carboxyl group-containing unsaturated compound in the component (A) is preferably 0.1 to 8% by weight, more preferably 0.2 to 7% by weight.

The content of the component (A) in the thermoplastic resin composition is preferably 90 to 40% by weight, and more preferably 8 to 40% by weight.
It is 0 to 45% by weight, more preferably 70 to 50% by weight.

Examples of the fibrous inorganic filler of the component (B) used in the present invention include carbon fibers, whiskers, glass fibers, etc., preferably carbon fibers and whiskers, and more preferably carbon fibers.

The carbon fiber is usually obtained by firing and carbonizing or graphitizing an organic fiber such as rayon or polyacrylonitrile. The carbon fiber is obtained by coding a metal such as nickel for shielding electromagnetic waves, or by dispersing carbon fiber. A material coated with a sizing agent may be used to improve the quality.

Examples of the material of the whisker include aluminum borate, silicon carbide, silicon nitride, potassium titanate, basic magnesium sulfate, zinc oxide, graphite, magnesia, calcium sulfate, sodium calcium phosphate, magnesium borate, titanium diboride, α-alumina, chrysotile, wollastonite, and the like. Since the fluidity of the resin composition is affected by the volume of the component (B), the whisker preferably has a high specific gravity in order to suppress an increase in the volume, and the specific gravity is preferably 2 or more, more preferably 2.5 or more, and more preferably 2 or more. .99 or more is more preferable.

The content of the component (B) in the thermoplastic resin composition is preferably 5 to 60% by weight, more preferably 5 to 60% by weight.
It is 50% by weight, more preferably 10 to 40% by weight.

Examples of the liquid crystal polymer (C) used in the present invention include aromatic-aliphatic polyesters, wholly aromatic polyesters, aromatic polyazomethylenes, and polyimide esters. The compounds shown are selected.

Examples of the aromatic-aliphatic polyester include a copolymer of polyethylene terephthalate and benzoic acid. Examples of the completely aromatic polyester include a copolymer of parahydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; a copolymer of parahydroxybenzoic acid, terephthalic acid and 6-hydroxy-2-naphthol. Examples of the aromatic polyazomethylene include poly (nitrilo-2-methyl-1,4-phenylenenitroethylidene). Examples of the polyimide polyester include a copolymer of 2,6-naphthalenedicarboxylic acid, terephthalic acid and 4 (4-hydroxyphthalimide) phenol, and a copolymer of diphenol and 4- (4-hydroxyphthalimide) benzoic acid. Can be The determination that these copolymers are liquid crystal polymers is made by confirming that the liquid crystal polymers show optical anisotropy in a molten state. For example, a test piece adjusted to a thickness of 1 mm or less is placed on a heating stage of a deflection microscope, and placed under a nitrogen atmosphere.
Heat at a heating rate of ° C / min. In this state, it can be easily confirmed by making the deflector of the deflection microscope orthogonal and observing it at a magnification of 40 times or 100 times. In such a method, the temperature at which these copolymers transition to the liquid crystal phase can be measured at the same time, and the transition temperature is determined by differential scanning calorimetry (D
SC).

The content of the component (C) in the thermoplastic resin composition is preferably 5 to 60% by weight, more preferably 5 to 60% by weight.
It is 50% by weight, more preferably 20 to 40% by weight.

In the thermoplastic resin composition of the present invention,
In order to provide a good balance between the fluidity of the composition and the rigidity of the molded product, the mixing ratio of the components (B) and (C) among the components (A), (B) and (C) is particularly important. Becomes
The compounding ratio (B) / (C) of the component (B) and the component (C) is preferably 1.2 to 20, more preferably 1.5 by weight.
To 15, more preferably 1.5 to 10.

The resin composition of the present invention may contain, if necessary, a flame retardant (a hydrated metal flame retardant such as aluminum hydroxide or magnesium hydroxide, a bromo flame retardant, a chlorine flame retardant, a phosphorus flame retardant ( Inorganic flame retardants such as red phosphorus, phosphate esters, antimony trioxide, etc.], stabilizers against heat, light or oxygen (antioxidants such as phenolic compounds and phosphorus compounds; benzotriazole compounds, benzophenone compounds) Compounds, ultraviolet absorbers such as phenyl salicylate compounds; hindered amine stabilizers, heat stabilizers such as tin compounds and epoxy compounds, etc.), plasticizers, slidability improvers such as polydimethylsiloxane, lubricants, release agents, charging You may add an inhibitor, a coloring agent, etc.

The thermoplastic resin composition of the present invention has an MI (2
60 ° C., load 5 kg) is 1 to 500 g / 10 min, preferably 2 to 300 g / 10 min, more preferably 3 to 100 g / 10 min.
g / 10 minutes.

Further, the thermoplastic resin composition of the present invention comprises:
The flexural strength on a / 16 inch test specimen is 6,000-50,
000MPa, preferably 7,000-40,000M
Pa, more preferably 8,000 to 40,000 MPa
It is.

The molded article of the present invention can be obtained by molding a thermoplastic resin composition by various molding methods such as extrusion molding, injection molding, etc., and includes electroplating, electroless plating, hot-dip plating, impact plating, and vacuum plating. The surface of the molded article can be metal-plated by a known metal plating method such as plating or chemical vapor deposition.

Since the thermoplastic resin composition of the present invention has good fluidity and excellent rigidity, it is particularly suitable as a molded product of a thin molded product. The molded product of the present invention is required to have a thin and high rigidity. It is suitable for use in small electronic devices, for example, as a thin molded product such as a mobile phone, a video camera, a notebook personal computer, and a tray for transporting a liquid crystal panel.

[0031]

The present invention will be described in more detail with reference to the following examples. In the following Examples and Comparative Examples, the following components are used, and the test methods of the Examples and Comparative Examples are as follows. (1) Resin composition (A) component PA: nylon 6, number average molecular weight 12,000 PC: polycarbonate, number average molecular weight 18,000 ABS resin: styrene content 45%, acrylonitrile content 1
5%, rubber content 40% maleic acid-modified ABS resin: styrene content 48%, acrylonitrile content 12%, rubber content 40%, maleic acid content 3% (B) component Carbon fiber: Vesfite HTA-C6-NR (diameter 7)
(μm, fiber length: 6 mm) (C) component Liquid crystal polymer: VECTRA A950RX (manufactured by Polyplastics Co., Ltd.) (2) Test method Fluidity (g / 10 min): Fluidity is other than 5 kg load at 260 ° C. Was measured based on JIS K7210.

Flexural modulus (MPa): Using an injection molding machine (cylinder temperature 250 ° C., mold temperature 60 ° C.), test specimens having a thickness of 1/4, 1/8 and 1/16 inch are prepared for a bending test. And measured according to ASTM D790. Examples 1 to 5 and Comparative Examples 1 and 2 Each component was blended in the composition shown in Table 1 and melt-kneaded with an extruder (single-screw extruder, twin-screw extruder) to obtain a pellet-shaped resin composition. . The extrusion temperature was 250 ° C. The single-screw extruder extruded all the raw materials including carbon fibers from the main feeder at once, and the twin-screw extruder extruded only the carbon fibers from the side feeder. In addition, 1
The screw of the screw extruder used was a full flight type screw. The test shown in Table 1 was performed for each composition.

[0033]

[Table 1]

In Examples 1 to 4, molding was easy because of good fluidity, and the obtained molded article was excellent in rigidity (flexural modulus). In Example 5, although the rigidity was excellent,
Since the (B) / (C) ratio was higher than the other examples,
The fluidity was low and the moldability was not good. In Comparative Example 1, although the fluidity was high and the moldability was good, the rigidity of the molded article was inferior because the (B) / (C) ratio was less than 1. Comparative Example 2
Had low fluidity and could not be extruded.

[0035]

The thermoplastic resin composition of the present invention has excellent moldability due to its good fluidity, and also has excellent rigidity of the molded article. Therefore, it is suitable for manufacturing thin-walled molded products, and can be used as a substitute for an alloy, for example, a magnesium alloy.

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[Procedure amendment]

[Submission date] March 21, 2000 (200.3.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

The present invention comprises (A) a thermoplastic resin, (B) a fibrous inorganic filler and (C) a liquid crystal polymer, and has an MI of 260 ° C., a load of 5 kg and a load of 1-500.
Flexural elasticity on g / 10 min and 1/16 inch specimen
Provided is a thermoplastic resin composition having a rate of 20,000 to 50,000 MPa.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

Further, the thermoplastic resin composition of the present invention comprises:
The flexural modulus on a / 16 inch test specimen is 6,000 to 5
0,000 MPa, preferably 7,000 to 40,000
0 MPa, more preferably 8,000 to 40,000 M
Pa.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 25/04 C08L 25/04 51/04 51/04 67/00 67/00 69/00 69/00 77/00 77 / 00 C23C 28/00 C23C 28/00 A F-term (reference) 4F071 AA12X AA14 AA22 AA22X AA43 AA50 AA54 AA75 AA88 AB03 AD01 AF17Y BA01 BB05 4J002 BB00W BC02W BN15W CF00W CF18X CG00W CL00W DA016 AB04 FA04A CA13 CA14 CA15 CA18

Claims (9)

[Claims] 1. A thermoplastic resin comprising (A) a thermoplastic resin, (B) a fibrous inorganic filler and (C) a liquid crystal polymer, and having an MI of 260
° C, 1 kg to 500 g / 10 min under a load of 5 kg, and 1/1
Flexural strength on a 6-inch specimen is 6,000 to 50,000
A thermoplastic resin composition having a pressure of 0 MPa. 2. The composition according to claim 1, wherein the proportion of the component (A) is 90 to 40% by weight,
The thermoplastic resin composition according to claim 1, wherein the proportion of the component (B) is 5 to 60% by weight and the proportion of the component (C) is 5 to 60% by weight. 3. The compounding ratio of component (B) to component (C) (B)
The thermoplastic resin composition according to claim 1, wherein / (C) is 1.2 to 20 in weight ratio. 4. The composition according to claim 1, wherein the component (B) is a carbon fiber.
4. The thermoplastic resin composition according to any one of the above items 3. 5. The method according to claim 1, wherein the component (A) is at least one selected from the group consisting of a polyamide resin, a polystyrene resin, an ABS resin, a polyester resin, a polycarbonate resin, and a polyolefin resin. Thermoplastic resin composition. 6. The composition according to claim 1, wherein the component (A) comprises a polyamide resin and ABS.
The thermoplastic resin composition according to any one of claims 1 to 5, which is a resin. 7. The thermoplastic resin composition according to claim 1, wherein the component (A) is a polycarbonate resin and an ABS resin. 8. A molded article comprising the thermoplastic resin composition according to claim 1. 9. The molded article according to claim 8, which is metal-plated.