Method of preparing flameproof thermoplastic resin composition

Details Method of preparing flameproof thermoplastic resin composition Method of preparing flameproof thermoplastic resin composition

2000-05-31

2003-11-25

Medley, Margaret (Department: 1714)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

C524S127000, C524S141000, C524S145000, C525S09200D, C525S09200D, C525S134000, C525S392000, C525S502000, C252S607000

Reexamination Certificate

active

06653374

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method of preparing flameproof thermoplastic resin composition. More particularly, the present invention relates to a method of preparing flameproof thermoplastic resin composition using an ABS resin and a polyphenylene ether resin as a base resin, a styrene-acrylonitrile copolymer containing from 5 to 18% by weight of acrylonitrile as a compatibilizer, and an aromatic phosphoric acid ester compound as a main flame retardant.
BACKGROUND OF THE INVENTION
A rubber modified styrene-containing resin has a good processability, a high impact strength, and a good appearance. Accordingly, the resin has been widely applied to electric appliances and office supplies. In case that a rubber modified styrene-containing resin is applied to personal computers, facsimiles, and the like, which emit heat, flame-retardant property should be given to the resin due to a combustibility.
A widely known method for the flame retardancy is that halogen-containing compounds or antimony-containing compounds are added to a rubber modified styrene-containing resin to give flame-retardant property. The halogen-containing compounds used in above method are, for example, polybromodiphenyl ether, tetrabromobisphenol A, epoxy compounds substituted by bromine, chlorinated polyethylene, etc. An antimony trioxide and an antimony pentaoxide are commonly used as antimony-containing compounds.
The methods for improvement of flame-retardant property by applying halogen- and antimony-containing compound have advantages such as easy acquirement of the flame-retardant property and no degradation of the physical properties. However, the disadvantages could be observed that the halogen-containing compound results in the corrosion of the mold itself by the hydrogen halide gases released during the molding process and is fatally harmful due to the toxic gases liberated in case of fire. Especially, since a polybromodiphenyl ether, mainly used for a halogen-containing flame retardant, can produce toxic gases such as dioxin or furan during combustion, flame retardants which are not prepared with halogen-containing compound have become main concerns in this field.
It is commonly known a method to apply phosphorus or nitrogen compounds as halogen-free flame retardant to a resin composition. However, usage of only phosphorus compound deteriorates heat resistance of a rubber modified styrene-containing resin and does not impart sufficient flame retardancy.
Generally, when a rubber modified styrene-containing resin such as ABS is burned, a char is not produced due to decomposition and vaporization in most parts (Journal of Applied Polymer Science, 1998, vol 68, p1067). Therefore, to impart an effect of flame retardancy, it is necessary to add a char-forming agent to a resin composition, which plays a role to prohibit entrance of oxygen and emission of fuel by forming char on the surface of rubber with three-dimensional carbon chain bonds under combustion.
Japanese Patent Laid-open No. 7-48491 discloses a flameproof thermoplastic resin, made of adding a novolac phenolic resin and a phosphoric acid ester into a thermoplastic copolymer resin composed of a rubber copolymer and an aromatic vinyl monomer. It was found that in order to obtain a good property of flame retardancy, a phenolic resin as a char-forming agent and a phosphoric acid ester compound as a flame retardant should be added in a lot of amount. However, in this case, the heat resistance of the resin composition is dropped suddenly.
U.S. patent application Ser. No. 09/233415 discloses a halogen-free flameproof resin composition having a good property of flame retardancy prepared by mixing a styrene-acrylonitrile (SAN) copolymer having from 5 to 18% by weight of acrylonitrile as a compatibilizer, an aromatic phosphoric acid ester compound as a main flame-retardant and a phenolic resin as a further flame-retardant to improve flame-retardant property of a resin composition and adding the mixture to a base resin comprising a rubber-modified styrene-containing resin and a polyphenylene ether resin. Good mechanical properties as well as a good improvement of flame retardancy and heat resistance were obtained, however, a phenolic resin used as char-forming agent of ABS resin causes the degradation of heat stability and weatherability.
The present inventors have found flameproof resin composition containing no phenolic resin in order to solve the above-mentioned problem. Generally, as the blend comprising an ABS resin and a polyphenylene ether resin have no compatibility each other, physical properties are degraded during extrusion processing to cause a poor property of mechanical strength. Accordingly, the present inventors have invented phenol-free flameproof thermoplastic resin composition which has a good property of mechanical strength by adding a styrene-acrylonitrile (SAN) copolymer or ABS resin containing a particular amount of acrylonitrile therein as a compatibilizer, in order to impart compatibility to the blend comprising an ABS resin and a polyphenylene resin.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a method of preparing a thermoplastic resin composition which has a good mechanical property, heat resistance and flame retardancy.
Another object of the present invention is to provide a method of preparing a flameproof thermoplastic resin composition which does not contain halogen-containing compounds which causes the environmental pollution during the preparation or combustion of the resin.
A further object of the present invention is to provide a thermoplastic resin composition which contains no phenolic resin and imparts compatibility to a blend comprising an ABS resin and a polyphenylene resin by adding a SAN or ABS copolymer containing a particular amount of acrylonitrile as a compatibilizer.
A further object of the present invention is to provide a flameproof thermoplastic resin composition according to the said method.
Other objects and advantages of this invention will be apparent from the ensuing disclosure and appended claims.
SUMMARY OF THE INVENTION
A flameproof thermoplastic resin composition of the present invention comprises (A) 40 to 95 parts by weight of a rubber modified styrene containing resin composed of (a
1
) 20 to 100% by weight of a styrene-containing graft copolymer resin including 18 to 50% by weight of acrylonitrile in the copolymer excluding rubber; and (a
2
) 0 to 80% by weight of a styrene-containing copolymer resin containing 18 to 50% by weight of acrylonitrile; (B) 5 to 60 parts by weight of polyphenylene ether resin; (C) 2 to 40 parts by weight of a styrene-containing copolymer or styrene-containing graft copolymer resin having 5 to 18% by weight of acrylonitrile in the copolymer excluding per 100 parts by weight of the sum of (A) and (B); and (D) 5 to 30 parts by weight of an aromatic phosphoric acid ester compound per 100 parts by weight of the sum of (A) and (B). The method of preparing the flameproof thermoplastic resin is (i) preparing a master batch in the range of 40 to 95 parts by weight of polyphenylene ether (PPE) (B), 5 to 60 parts by weight of styrene-containing graft copolymer resin or styrene-containing copolymer resin having 5 to 18% by weight of acrylonitrile content, and 0 to 30 parts by weight of aromatic phosphoric acid ester compound (D) at 250 to 300° C. of molding temperature; and (ii) adding a rubber modified styrene-containing resin (A) and an aromatic phosphoric acid ester compound (D) to the master batch and extruding at 200 to 260° C. of molding temperature to be a final resin comprising 40 to 95 parts by weight of ABS resin, 5 to 60 parts by weight of PPE (B), and 5 to 30 parts by weight of aromatic phosphoric acid ester compound (D).
DETAILED DESCRIPTION OF THE INVENTION
The flameproof thermoplastic resin composition according to the present invention comprises (A) 40 to 95 parts by weight of a ABS resin composed of (a
1
) 20 to 100% by weight of a graft ABS copolymer resin including 18 to 50% by weight of acrylonitri

Affiliated with

Also associated with

Rating

Method of preparing flameproof thermoplastic resin composition does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of preparing flameproof thermoplastic resin composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of preparing flameproof thermoplastic resin composition will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3132918