JPH04146958A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To remarkably reduce drawdown and facilitate the blow molding of a large part by compounding at least one resin selected from the group consisting of a polycarbonate resin and a polybutylene terephthalate resin, a specific high-molecular weight acrylic copolymer, and carbon black. CONSTITUTION:100 pts.wt. at least one resin selected from the group consisting of a polycarbonate resin (derived from a dihydric phenol and having a viscosity average mol.wt. of 10000-100000, pref. 15000-60000) and a polybutylene terephthalate resin (pref. having an intrinsic viscosity in o-chlorophenol at 25 deg.C of 0.8-2.0), 0.1-8 pts.wt. acrylic copolymer [contg. at least 30wt.% alkyl methacrylate and at lest 5wt.% alkyl acrylate and having a relative viscosity (0.1g polymer/10dl methylene chloride) of 0.2 or higher], and 0.5-6 pts.wt. carbon black (having a specific surface area of 150m<2>/g or higher and an oil absorption of 500ml/100g or higher) are compounded to give a thermoplastic resin compsn. suitable for blow molding.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is directed to a thermoplastic resin mainly composed of polycarbonate resin, polybutylene terephthalate resin, or a mixture thereof, which has improved drawdown properties and is suitable for blow molding. Regarding the composition.

<Prior Art> Polycarbonate resins have excellent mechanical, thermal and electrical properties and are therefore used in a wide range of fields as engineering plastics. Polybutylene terephthalate resin also has excellent electrical properties and chemical resistance, and is widely used as an engineering plastic.

Various molding methods are used to mold polycarbonate resin and polybutylene terephthalate resin, but these resins all have poor drawdown properties, so blow molding can only yield small molded products, and the drawdown properties are poor. Improvements are desired.

Conventionally, as a method for improving the drawdown properties of polycarbonate resins, Japanese Patent Publication No. 53-28193 proposes a method of copolymerizing a branching agent having three or more phenolic hydroxyl groups. However, branched polycarbonate resins obtained in this way are difficult to purify, tend to contain unreacted substances and by-products, and have the drawbacks of coloring during molding and deterioration of physical properties. It has the disadvantage of gelling, making it difficult to put it into practical use.

Further, JP-A-1-268761 proposes a method of blending an acrylic polymer having a weight average molecular weight of at least about 500,000 as a melt rheology modifier with a polycarbonate resin or a polyester resin. Although this method improves the drawdown properties of polycarbonate resin to some extent, it is still not sufficient as blow molded products have become increasingly larger in recent years. Furthermore, with respect to polybutylene terephthalate resin, the drawdown property is hardly improved. Furthermore, when the above-mentioned acrylic polymer is added to a mixture of polycarbonate resin and polybutylene terephthalate resin and the mixture is melt-extruded, when the molten resin is extruded from a die, a phenomenon occurs in which the resin swells to a size larger than the size of the die. Since this occurs simultaneously with drawdown, the wall thickness tends to change easily, and there is a drawback that it is difficult to obtain a molded product with a uniform wall thickness.

<Object of the invention> The present invention solves these problems and provides a polycarbonate resin, a polybutylene terephthalate resin, or a mixture thereof, which has excellent drawdown properties and can be easily blow-molded into large molded products. With the goal.

As a result of intensive studies aimed at achieving the above object, the present inventors have found that drawdown of polycarbonate resin, polybutylene terephthalate resin, or a mixture thereof can be achieved by using a specific highly polymerized acrylic copolymer together with a specific carbon black. The present invention was completed based on the discovery that the properties can be significantly improved.

<Configuration of the Invention> The present invention provides at least one resin 10 selected from polycarbonate resin and polybutylene terephthalate resin.
0 parts by weight, fA) an acrylic copolymer containing at least 30% by weight of alkyl methacrylate and at least 5% by weight of alkyl acrylate, a solution of the polymer of 019 in 1 deciliter of methylene chloride. About 2
An acrylic copolymer with a specific viscosity of 0.2 or more when measured at 5°C, and (B) a specific surface area (by BET low-temperature nitrogen adsorption droplet) of 1.
More than 50TIl/g and oil absorption amount is 5001d! / 1
The present invention relates to a thermoplastic resin composition containing 0.5 to 6 parts by weight of carbon black having a carbon black of 009 or higher.

The polycarbonate resin used in the present invention has a viscosity average molecular weight of 10.000 to 10 derived from dihydric phenol.
0.000, preferably 15,000 to 60,000, and is usually produced from a dihydric phenol and a carbonate precursor by a solution method or a melt method.

The dihydric phenol used here is 2,2-bis(
The main target is 4-hydroxyphenyl)propane (commonly known as bisphenol A), but part or all of it may be replaced with other dihydric phenols. Other dihydric phenols include, for example, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,
2.2-bis(4-hydroxy-3-methylphenyl)
You can give propane, etc. Examples of carbonate precursors include carbonyl halides, carbonyl esters, heroformates, and specific examples include phosgene, diphenyl carbonate, and dihaloformates of dihydric phenols. Further, when producing the polycarbonate resin, appropriate molecular weight regulators, catalysts, etc. may be used.

Polybutylene terephthalate resin is a polymer obtained by reacting terephthalic acid or its ester-forming derivative with tetramethylene glycol or its ester-forming derivative as main raw materials, and its molecular weight is not particularly limited, but is Those having an intrinsic viscosity of about 08 to 20 when measured at 25° C. using a polyphenol as a solvent are preferably used. In addition, the above polybutylene terephthalate has
Up to 30 mol% of terephthalic acid may be replaced with other dicarboxylic acids;
Up to mol% may be replaced with other diols. Examples of other dicarboxylic acids include isophthalic acid and naphthalene dicarboxylic acid, and examples of other diols include polymethylene-α other than tetramethylene glycol.
, ω-diols, neopentyl glycol, diethylene glycol, and the like. The molecular weight of the above-mentioned polybutylene terephthalate is not particularly limited, but the intrinsic viscosity measured at 25°C using chlorophenols as a solvent is 0.6
~20 is preferably used.

The (^) acrylic copolymer used in the present invention is a random copolymer consisting of 30% by weight or more of alkyl methacrylate and 5% by weight or more of alkyl acrylate, and is mainly composed of methyl methacrylate. A random copolymer consisting of an alkyl methacrylate and an alkyl acrylate mainly containing butyl acrylate is preferred. In addition, 30% by weight or more of alkyl methacrylate and 5% by weight of alkyl acrylate
One or more types of other copolymerizable monomers may be copolymerized within a range that satisfies the condition of weight % or more. Examples of other copolymerizable monomers include aromatic vinyl, vinyl cyanide, vinyl esters, etc. Furthermore, it is also possible to use polyfunctional monomers such as divinylbenzene, diallyl phthalate, and triallyl cyanurate. be.

The molecular weight of such an acrylic copolymer is such that the specific viscosity measured at 25° C. in a solution of 0.1 g of the copolymer dissolved in 1 deciliter of methylene chloride is 0.2 or more. If the specific viscosity is less than 0.2, it is difficult to exhibit the effect of improving drawdown properties.

(B) Carbon black used in the present invention has a specific surface of 8!1f (based on BET low-temperature nitrogen adsorption method) of 150 m/
carbon black with an oil absorption of 500 d/100'j or more, and a specific surface area of 500 m/!
7 or more and an oil supply amount of 500 d/100 (j or more) is preferable. Carbon black whose specific surface area and oil absorption amount are outside the above ranges has almost no effect of improving drawdown properties. .

Such carbon blacks include those commercially available as conductive carbon blacks, such as Lion Akzo.
Ketchen Black EC manufactured by Cabot, Palkan X manufactured by Cabot
C-72, Black Pearl 2000, Denki Kagaku Kogyo■
Denka Black manufactured by Degussa, Printex manufactured by Degussa
Carbon black, which is produced as a by-product when a hydrocarbon such as naphtha is partially oxidized in the presence of steam and oxygen to produce a synthesis gas containing hydrogen and carbon oxide, or carbon black obtained by oxidation treatment thereof, etc., can be mentioned.

The ratio of (A) acrylic copolymer and (B) carbon black to be blended into polycarbonate resin, polybutylene terephthalate resin, or a mixture thereof is as follows: FA) component is 01 to 8 parts by weight, based on 1001 parts by weight of the resin component.
fB] component is 05 to 6 parts by weight, preferably (
The Al component is 0.6 to 5 parts by weight, and the component (B) is 2 to 4 parts by weight. When the amounts of component (A) and component CB) do not reach the above amounts, the improvement in drawdown properties is not sufficient;
The improvement effect increases as the amounts of (A) and (B) ingredients increase, but (8) if the amount of ingredients exceeds 8 parts,
If component fB) exceeds 6 parts by weight, the mechanical properties may deteriorate or the surface of the molded product may become rough.

Note that the mechanical properties, thermal properties, chemical resistance, etc. of the resulting composition depend on the properties of the polycarbonate resin and polybutylene terephthalate resin, and the mixing ratio of both can be adjusted according to the required performance.

For example, impact modifiers, inorganic fillers, R-free fibers, etc. can be added to the resin composition of the present invention, if necessary.

Examples of inorganic fillers include talc, silica, diatomaceous earth,
Examples of the inorganic IIH include mica, alumina, and calcium carbonate, and examples of the inorganic IIH include glass IN and whiskers. In addition, other additives such as lubricants, stabilizers, antioxidants, ultraviolet absorbers, etc. may be used as necessary within a range that does not impair the purpose of the present invention.

In particular, it is preferable to incorporate an impact modifier. Examples of impact modifiers include acrylic elastomers, butadiene polymers, modified polyolefin polymers, etc. Among them, two or more types of vinyl monomers that can be copolymerized in the presence of diene rubber are used as impact modifiers. Graft copolymers obtained by polymerization are preferred. The diene rubber mentioned here is
For example, polybutadiene, polyisoprene, butadiene
Examples include styrene copolymer, butadiene-acrylic L-lyl copolymer, and the like.

Examples of vinyl monomers that can be copolymerized with these rubber components include vinyl cyanide compounds such as acrylonitrile, methacrylonitrile, and chloroacrylonitrile, styrene, α-methylstyrene, ρ-methylstyrene, amethoxystyrene, and halogenated styrene. Aromatic vinyl compounds such as methyl acrylate, ethyl acrylate, butyl acrylate, lower alkyl esters of acrylic acid such as octyl acrylate, methacrylic acid such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, etc. Examples include lower alkyl esters of. The amount of these impact modifiers is usually 20 parts by weight or less per 100 parts by weight of polycarbonate resin, polybutylene terephthalate resin, or a mixture thereof.

Any method can be used to produce the resin composition of the present invention, and generally, the components are tri-blended using a tumbler blender, Nauta mixer, etc., and then melt-kneaded and extruded, or an extruder equipped with an automatic metering feeder is used. Examples include a method of kneading. In any case, conditions and equipment that allow each component to be sufficiently dispersed and mixed may be selected. Examples of the mixing device include a Banbury mixer 1 mixing roll, an extruder, a kneader, and the like.

<Effects of the Invention> Since the resin composition of the present invention has improved drawdown properties, it is suitable for blow molding and vacuum molding, and is suitable for other molding methods such as injection molding, extrusion molding, compression molding, etc. It can also be applied to Furthermore, the composition is not only easy to mold, but also has excellent mechanical properties and a high deflection temperature under load, making it an extremely useful composition from an industrial standpoint.

<Example> The present invention will be specifically described below with reference to Examples. In addition, the part in an Example means the important part.

Tensile strength, impact strength (with slit notch, 1/8”
) and load deflection temperature were measured according to the STH standard. The drawdown property test was performed by drying the pellet at 120°C for 4 hours and using a 30m+φ extruder (VSK manufactured by Chuo Kikai Seisakusho).
-30), extrusion temperature 250℃, extrusion speed 6/(9/
Melt extrusion from a nozzle with a diameter of 4#φ at 100 hr, cut the thread hanging down from the nozzle as appropriate, measure the minimum diameter of the thread, and create a relationship diagram as shown in Figure 1. The drawdown property was evaluated using the weight at which the diameter changes as the limit value. The larger the obtained limit value, the better the drawdown property, and a limit value of 8 g or less was rejected. Further, the swell ratio, which is considered important in blow molding, was calculated from the following formula: swell ratio - thread diameter/nozzle diameter. Generally, it is said that the larger the swell ratio, the better for large-scale blow molding, but since drawdown occurs at the same time, if it becomes extremely large, a significant change in wall thickness will result, so a swell ratio of 15<35 was considered acceptable.

Production of acrylic copolymer 300 parts of distilled water was added to a reaction vessel equipped with a stirrer and a reflux condenser.
1.8 parts of sodium dioctyl sulfosuccinate, 0.24 parts of ammonium persulfate, 102 parts of methyl methacrylate, 18 parts of -butyl acrylate, and 0.06 parts of n-octyl mercaptan were charged, and the mixture was replaced with an inert gas at 58°C.
The mixture was heated and stirred according to a conventional method to obtain an acrylic copolymer (2) having a specific viscosity of 1.68. Furthermore, acrylic copolymers with different specific viscosities (specific viscosity 0.48), ■ (specific viscosity 0.24), ■ <specific viscosity 0.24>, (specific viscosity 005) was obtained.

Examples 1 to 12 and Comparative Examples 1 to 12 After tri-blending polycarbonate resin, polybutylene terephthalate resin, acrylic copolymer, carbon black, and HBS resin as an impact modifier in a blender in the proportions shown in Table 1. The mixture was melt-kneaded and pelletized using a 305φ vented extruder at a cylinder temperature of 270°C. The resulting pellet was injection molded (J-120SA manufactured by Japan Steel Works, Ltd.) to create a physical property test piece at a cylinder temperature of 260°C or 280°C, and the tensile strength, impact strength and deflection temperature under load were measured. The results are shown in Table 1.

Furthermore, the drawdown properties were evaluated using the pellets prepared by the above method, and the thread tip diameter was measured to determine the swell ratio. The results are shown in Table 1.

Polycarbonate resin (Panlite L1250 manufactured by Yojin Kasei Corporation) POT with PC biviscosity average molecular m 25.000 in Table 1
: Polybutylene terephthalate resin with intrinsic viscosity 107 (TRB-H manufactured by Teijin ■) HBS : HBS resin (Paraoid EXL-2602 manufactured by Kureha Chemical Industry ■) Acrylic copolymer ■: Specific viscosity 168 Acrylic copolymer ■: Ratio Viscosity 048 Acrylic copolymer ■: Specific viscosity 0.24 Acrylic copolymer ■: Specific viscosity 0.05 Carbon black A: Specific surface area 970rd/9, oil absorption 930a+! , / 100g (Denka Black manufactured by Denki Kagaku Kogyo ■) Carbon black B: Specific surface area 134 m, /'F, oil absorption 100 td/ (Mitsubishi Carbon Black HA-1001 manufactured by Mitsubishi Chemical Industries ■ (margins below)

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the thread diameter and its weight for measuring the drawdown limit value. ■ indicates the drawdown limit value of Example 2, ■ indicates Example 8, ■ indicates Example 12, and ■ indicates Comparative Example 9.

Claims (1)

[Scope of Claims] 100 parts by weight of at least one resin selected from polycarbonate resin and polybutylene terephthalate resin, (A) an acrylic material containing at least 30% by weight of alkyl methacrylate and at least 5% by weight of alkyl acrylate; 0.1 to 8 parts by weight of an acrylic copolymer having a specific viscosity of 0.2 or more when measured at 25°C in a solution of 0.19% of the polymer dissolved in 1 deciliter of methylene chloride. and (B) specific surface area (by BET low temperature nitrogen adsorption method) is 1
50m^3/g or more and oil absorption 500ml/100
A thermoplastic resin composition containing 0.5 to 6 parts by weight of carbon black.