Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-01-16
2004-04-06
Szekely, Peter (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S141000, C524S143000
Reexamination Certificate
active
06716900
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a flameproof thermoplastic resin composition. More particularly, the present invention relates to a flameproof thermoplastic resin composition substantially free of phenolic resins that comprises a rubber modified styrene-containing resin and a polyphenylene ether resin as a base resin, a styrene-acrylonitrile copolymer as a compatibilizer, and an aromatic phosphoric acid ester as a 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 for inhibiting combustibility thereof. A widely known method for the flame retardancy is that a halogen-containing compound or a antimony-containing compound is added to a rubber modified styrene-containing resin to give flame-retardant property. The examples of 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 or an antimony pentaoxide is commonly used as an antimony-containing compound.
The methods for improvement of flame-retardant property by applying a 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 prepared without a halogen-containing compound have become a major concern in this field.
It is commonly known to apply a phosphorus or nitrogen compound as halogen-free flame retardant to a resin composition. However, usage of only a 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 has been considered 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 by 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 large amount of phosphoric acid ester compound as a flame retardant is required. However, in this case, the heat resistance of the resulting resin composition is reduced.
U.S. Pat. No. 4,618,633 (Taubitz et al.) discloses thermoplastic compositions containing polyphenylene ether and a styrene-acrylonitrile copolymer that also contain novolaks (linear, non-crosslinked phenol/aldehyde resins) which are disclosed as being added to compensate the decrease in heat distortion resistance resulting from the addition of phosphorous flameproofing agents.
U.S. Pat. No. 5,605,962 (Suzuki et al.) discloses flame retardant compositions containing specific rubber-reinforced resins, a phenol resin, and an organic phosphorous compounds as flame retardants. Other resins are disclosed as optionally present include polyphenylene oxide.
U.S. Pat. No. 4,360,618 (Trementozzi) and U.S. Pat. No. 4,578,423 (Deets et al.) disclose polyblends of polyphenylene oxide and styrene/acrylonitrile polymers which have specified acrylonitrile content. The use of SAN copolymers as compatabilizers for polyphenylene oxide and ABS type resins is not disclosed.
U.S. Pat. No. 5,621,029 (Eckel et al.) disclose flame retardant thermoplastic resin compositions prepared from polycarbonate and graft copolymer. The flame retardant used in the compositions is a synergistic combination of silicone resin and polyphenylene oxide to reduce the amount of phosphoric ester flame retardant. As disclosed in U.S. Pat. No. 4,618,633, decrease in properties such as heat distortion resistance results from the addition of phosphorous flameproofing agents. In U.S. Pat. No. 5,621,029, styrene-acrylonitrile copolymers are disclosed as optional components. The amounts of ABS polymer and the polyphenylene oxide are minor compared to the major amount of the base resin, polycarbonate so compatability of the ABS polymer and polyphenylene is not addressed by the reference.
U.S. Pat. No. 4,966,814 (Ohzeki) discloses a flame retardant composition that is susceptible to electroless plating comprising polyphenylene ether resin and a rubber-modified resin that also comprises red phosphorous and phosphoric acid ester in specific amounts. The lower limit of the amount of red phosphorous is 1% by weight. When a lower amount, 0.8% by weight was used, the flame retardance of the composition was poor. Moreover, the use of red phosphorous disclosed in U.S. Pat. No. 4,966,814 would be expected to result in the production of toxic phosphine gas during the process of preparing the compositions or during the combustion of products made from the compositions. Furthermore, the presence of even small amounts of red phosphorous cause a reddish color in the resulting resin composition.
U.S. Ser. No. 10,011,056, herein incorporated by reference, discloses a halogen-free flameproof resin composition having a good property of flame retardancy prepared by mixing a styrene-acrylonitrile 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, the use of a phenolic resin as char-formation agent of ABS resin causes the degradation of heat stability and weatherability.
SUMMARY OF THE INVENTION
A flameproof thermoplastic resin composition substantially free of phenolic resin and red phosphorous comprising:
(A) about 40-95 parts by weight of a rubber modified styrene-containing resin comprising:
(a1) about 20-95% by weight of a styrene-containing graft copolymer resin containing about 19-50% by weight of acrylonitrile in the copolymer excluding rubber and
(a2) about 5-80% by weight of a styrene-containing copolymer containing about 19-50% by weight of acrylonitrile;
(B) about 5-60 parts by weight of a polyphenylene ether resin;
(C) about 2-40 parts by weight of a compatabilizer comprising
(c1) a styrene-containing copolymer containing about 5-18% by weight of acrylonitrile in the copolymer per 100 parts by weight of the sum of (A) and (B) or
(c2) a styrene-containing graft copolymer having up to about 60% by weight of rubber wherein the compatabilizer contains about 5-18% by weight of acrylonitrile in the copolymer excluding rubber, per 100 parts by weight of the sum of (A) and (B); and
(D) about 5-30 parts by weight of an aromatic phosphoric acid per 100 parts by weight of the sum of (A) and (B). The physi
Chang Young-Kil
Jang Bok-Nam
Kim Se-Jong
Lee Gyu-Cheol
Cheil Industries Inc.
Szekely Peter
Tungol Maria Parrish
LandOfFree
Flameproof styrene containing graft resin compositions... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flameproof styrene containing graft resin compositions..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flameproof styrene containing graft resin compositions... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3221831