Flame retardant plastic resin composition

Abstract

The invention relates to a flame-retardant thermoplastic resin composition having incorporated therein a trace of stabilized red phosphorus, which achieves both improvement of heat resistance and flame retardation without using chlorine nor bromine and also possesses long-term heat stability and smells little. The composition comprises (A) 50 to 95 parts by weight of a polycarbonate resin and (B) 5 to 50 parts by weight of a thermoplastic polyester resin, contains (C) 0.1 to 5 parts by weight, per 100 parts by weight of the total amount of (A) and (B), of coated stabilized red phosphorus and preferably contains (D) 0.1 to 100 parts by weight, per 100 parts by weight of the total amount of (A) and (B), of a silicate compound.

Description

[0001] This invention relates to a flame-retardant thermoplastic resin composition. More particularly, it relates to a flame-retardant thermoplastic resin composition having incorporated therein a trace of stabilized red phosphorus, which achieves both improvement of heat resistance and flame retardation without using chlorine nor bromine and also possesses long-term heat stability and smells little.[0002] Polycarbonate resins are thermoplastic resins having excellent impact resistance and heat resistance and widely used as parts in the fields of machinery, automobiles, electricity and electronics. In particular aromatic polycarbonate resins have a high glass transition temperature and are expected to exhibit high heat stability. However, they frequently fail to show sufficient flowability in processing. Therefore, aromatic polycarbonate resins should be processed at relatively high processing temperatures around 300.degree. C. In molding aromatic polycarbonate resins by, for exampl...

AI Technical Summary

Benefits of technology

[0098] As long as the effects of the invention are not impaired, the flame-retardant resin composition according to the present invention can contain arbitrarily selected additional thermoplastic or thermosetting resins, for example, liquid crystal polyester resins, polyester ester elastomeric resins, polyester ether elastomeric resins, polyolefin resins, polyamide resins, polystyrene resins, polyphenylene sulfide resins, polyphenylene ether resins, polyacetal resins, and polysulfone resins, used either individually or as a combination of two or more thereof.

[0099] In order to further improve the performance of the flame-retardant resin composition of the invention, it is preferred to use antioxidants (e.g., phenol antioxidants and thioether antioxidants), heat stabilizers (e.g., phosphorus type stabilizers), and the like either individually or as a mixture of two or more thereof. If desired, the resin composition can contain one or more of other well-known additives, such as stabilizers, lubricants, parting agents, plasticizers, flame retardants other than phosphorus type compounds, flame retardation aids, ultraviolet absorbers, light stabilizers, pigments, dyes, antistatic agents, electric conductivity imparting agents, dispersants, compatibilizers, antimicrobials, and so on.

[0100] The method for preparing the flame-retardant resin composition of the invention is not particularly limited. For example, the composition is prepared by drying the above-mentioned components and additives, resins, etc. and melt-kneading them in a melt-kneading machine, such as a single- or twin-screw extruder. Where a compounding ingredient is liquid, it can be added to the barrel of a twin-screw extruder by means of a liquid feed pump.

[0101] The method for molding the thermoplastic resin composition prepared in the present invention is not particularly limited. Molding methods customarily employed for thermoplastic resins, such as injection molding, blow molding, extrusion molding, vacuum forming, press molding, calendering, expansion molding, and the like, can be applied.

[0102] The flame-retardant thermoplastic resin composition of the invention is suited to a variety of uses. Preferred uses include interior and exterior parts of appliances and office automation equipment, injection molded parts of automobiles, blow molded articles, extruded articles, expansion molded articles, etc.

[0103] The present invention will now be illustrated in greater detail by way of Examples, but it should be understood that the present invention is not limited thereto. Unless otherwise noted, all the parts and percents are given by weight.

Problems solved by technology

However, they frequently fail to show sufficient flowability in processing.

Red phosphorus is difficult to handle because for one thing it is a dangerous chemical having a danger of dust explosion and for another it tends to emit smell or gas when processed in high temperature.

However, addition of an organic phosphorus flame retardant to a polycarbonate resin in an attempt to impart sufficient flame retardance results in considerable reduction in heat resistance.

Polycarbonate resin compositions containing red phosphorus or stabilized red phosphorus lack long-term heat stability.

That is, moldings obtained suffer from deformation when exposed to a temperature no higher than around 150.degree. C. for a long time.

Besides, the compositions have poor molding processability because of low flowability.

If the compositions are molded at high temperatures to secure flowability, there arise different problems such that a smell attributable to red phosphorus issues during molding and that decomposition gas generates during molding to contaminate the mold.

In addition it is difficult with red phosphorus alone to obtain sufficient flame retardance.

However, addition of a large quantity of red phosphorus leads to a stronger smell attributable to red phosphorus, and a combined use of a flame retardation aid results in not only destruction of the balance of properties of the resin but an increase of cost.

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