JPS5928341B2 - Thermoplastic resin composition for molding containing mica powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic resin composition for molding containing mica powder having excellent moldability and mechanical properties.

More specifically, polystyrene or a thermoplastic resin mainly composed of styrene, mica powder, and a phosphoric acid compound are used for injection molding, extrusion molding, etc., and have extremely excellent fluidity and mechanical properties such as strength, elastic modulus, and surface hardness. The present invention relates to a thermoplastic resin composition used. A composite made of thermoplastic resin mixed with mica powder is, for example, disclosed in Japanese Patent Publication No. 49-186
15.

However, all of the composites described in the above-mentioned patents were obtained by compression molding, and according to the results of research by the present inventors, the fluidity of the composites in the molten state was reduced. It has become clear that when thermoplastic resins are molded by conventional molding methods such as injection molding, extrusion molding, etc., fluidity is insufficient. This phenomenon may cause the original performance not to be fully demonstrated when obtaining a desired molded product using the injection molding method, and it also becomes a serious hindrance especially when molding large molded products, reducing the practicality of the composite. You will be forced to do so. This poses a serious problem, especially in areas with large mica loadings that fully exhibit the characteristics of the composite. However, the present inventors have conducted extensive research in order to obtain a thermoplastic resin-mica composite with improved fluidity and excellent mechanical properties. It was discovered that by molding a resin, a thermoplastic resin-mica composite with dramatically improved fluidity, high elastic modulus, high strength, and high surface hardness without deterioration of its original performance could be obtained. , we have completed the present invention. As the mica used in the present invention, a wide variety of mica, such as muscovite, phlogopite, spodium, and synthetic corolovogrogite, can be used.

There are no restrictions on the particle size or aspect ratio of the mica to be added, but the particle size of the mica powder should be finer than 20 mesh, especially when used in molded products that require surface scratch strength. is desirable. There is also no restriction on the mixing ratio of the mica powder used, but it is preferably 1
It is 0 to 80% by weight.

10 weight? At the following mixing ratios, the fluidity of the composition is extremely good, but the performance of the molded product, especially the elastic modulus and heat resistance, is insufficiently improved. This poses a problem in that it has extremely poor properties and is difficult to mold using a general injection molding machine or extrusion molding machine.

Generally, the mica powder used in the present invention may be subjected to surface treatment in advance with a compound for improving the interfacial adhesive strength between the polymeric material and the inorganic powder, such as a silane coupling agent.

The resin used as the composite matrix in the present invention includes polystyrene or a thermoplastic resin containing styrene as a main component, such as styrene-acrylonitrile-
Examples include butadiene copolymer (ABS resin), styrene-acrylonitrile copolymer (SAN resin), styrene-butadiene copolymer (impact polystyrene), and the like.

The phosphoric acid compound preferably used in the present invention is an orthophosphoric acid triester having the structure of the following formula.

(R', W, and T are alkyl having 1 to 8 carbon atoms, haloalkyl, aryl, haloaryl) Particularly preferably, triphenyl phosphate, tricresyl phosphate, tris(2-chloroethyl) phosphate, tris(2,
Goodichloroisopropyl) phosphate, etc.
Depending on the type of polymer matrix, it is necessary to select one having a boiling point higher than the temperature at which the mica-thermoplastic resin composite is melt-molded.

The amount of the phosphoric acid compound added is not particularly limited, but it is preferably 0.1 to 5.0% by weight, more preferably 0.3 to 3% by weight of the polymer matrix.
It is 0.

If the addition rate is below this range, the effect of improving fluidity will not be significant, and if the addition rate is above this range, the physical properties of the molded article, particularly strength, impact strength, etc. will deteriorate, which is not desirable.
It is a well-known fact that the above-mentioned phosphorus compounds are used as flame retardants and plasticizers for thermoplastic resins such as polyvinyl chloride and styrene resins. Although the properties are improved, the mechanical properties of the molded product, especially the elastic modulus, strength, surface hardness, and heat resistance, especially the heat distortion temperature, are usually reduced, and by mixing the phosphorus compound, the fluidity is improved. At the same time, mechanical properties such as strength, elastic modulus, surface hardness, etc. are improved, which is a unique phenomenon that is clearly observed in polystyrene or thermoplastic resin monomica composites whose main component is styrene. Glass fibers can be used in combination with mica powder in the method of the invention.

A composite consisting of a thermoplastic resin, mica powder, and phosphorus compound has excellent fluidity during molding and excellent molded product performance, especially high modulus of elasticity, high strength, high heat resistance, and high chemical resistance. , low impact strength may be a drawback, and the combined use of a small amount of glass fiber is effective in improving the impact strength of the composite material. The mica powder and the phosphoric acid compound can be blended into the thermoplastic resin by a method well known to those skilled in the art.

The composite material produced according to the present invention can be formed into any shape such as mechanical parts, structural parts, sheets, rods, pipes, etc. by feeding it into ordinary injection molding machines, extrusion molding machines, compression molding machines, calender molding machines, etc. molded.

Note that during molding, there is no problem in adding known additives such as colorants, lubricants, stabilizers, and plasticizers.
The method of the present invention will be explained in more detail below with reference to Examples and Comparative Examples, but these Examples are not intended to limit the present invention in any way.

Comparative Example 1 70 parts of styrene-acrylonitrile copolymer resin pellets (Tyryl 783, manufactured by Asahi Tau Co., Ltd.) and 30 parts of phlogopite with a particle size of 100 to 200 mesh were mixed in a tumbler mixer, and then heated to a cylinder temperature of 240°C in an extruder. Mix with
Made pellets.

The obtained pellets were molded using a Nippon Steel Ankelberg 15-75 in-line screw type injection molding machine at a cylinder temperature of 230°C and 250°C, a mold temperature of 60'C,
Injection pressure 60Ky/CTl (gauge pressure), back pressure 10Ky/
(71 (gauge pressure)), injection time: 10 seconds, holding pressure time: 10 seconds, cooling time: 40 seconds to obtain a sample for circumference measurement.

Also, using the same equipment as above, cylinder temperature 230℃, mold temperature 60℃, injection pressure 30 and 60K2/CTlt (gauge pressure), back pressure 10Ky/c-rl (gauge pressure), injection time 10 seconds, holding pressure. A spiral flow test was conducted under the conditions of 10 seconds of cooling time and 20 seconds of cooling time to determine fluidity. The experimental results are shown in Table 1. Example 1 70 parts of styrene-acrylonitrile copolymer resin pellets (Tyryl 783, manufactured by Asahi Tau Co., Ltd.), 30 parts of phlogopite with a particle size of 100 to 200 mesh, and 0.5 part of trisdichloropropyl phosphate (CRP) were mixed in a tumbler mixer. After mixing in an extrusion molding machine (・(-, cylinder temperature 24
The mixture was mixed at 0'C to form pellets.

The pellets were injection molded in exactly the same manner as in Comparative Example 1 at a cylinder temperature of 23°C to obtain test pieces, and the spiral flow length was measured. The results of the first experiment are shown in Table 1. From the results shown in Table 1, it is clear that the resin composition of the present invention has significantly improved fluidity, and there is no deterioration in the mechanical performance of the molded product. Example 2 After mixing 4 volumes of styrene-acrylonitrile copolymer resin pellets (Tyryl 783, manufactured by Asahi Tau Corporation) with 70 parts of phlogopite powder of 100 to 200 mesh and 2 parts of triphenyl phosphate (TPP) using a dumbler mixer, The mixture was mixed using an extruder at 24°C to form pellets.

The pellets were prepared as Comparative Example. Injection molding was performed at 250°C in exactly the same manner as method 1 to obtain a test piece for performance measurement.
Further, the spiral flow length was measured at 230°C. The experimental results are shown in Table 1. It can be seen from the table that the fluidity was improved without deteriorating various physical properties. Example 3 Tricresyl phosphate (T
Table 1 shows the results of an experiment conducted in exactly the same manner as in Example 2, except that CP) was used.

As is clear from the table, fluidity is improved without deteriorating various physical properties. Example 4 Table 1 shows the results of an experiment conducted in exactly the same manner as in Example 1, except that trichloroethyl phosphate (CLP) was used instead of CRP.

It can be seen from the table that the fluidity was improved without deteriorating various physical properties. Comparative Example 2 In order to clarify the effect of adding a phosphoric acid compound to a styrenic resin that does not contain mica powder, first, only a styrene-acrylonitrile copolymer resin (Tyryl 783, manufactured by Asahi Tau Co., Ltd.) was subjected to the same conditions as in Comparative Example 1. injection molding was performed and the fluidity and physical properties of the injection molded product were measured.

Claims (1)

[Scope of Claims] 1. A thermoplastic resin composition for molding comprising a thermoplastic resin containing polystyrene or styrene as a main component, mica powder, and a phosphoric acid compound represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R' and R″R″′ are alkyl having 1 to 8 carbon atoms,
It is either haloalkyl, aryl or haloaryl. )