Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-06-21
2001-05-08
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S099000, C524S100000, C524S114000, C524S371000, C524S412000, C524S466000
Reexamination Certificate
active
06228911
ABSTRACT:
The present invention relates to a composition, comprising a) a styrene, &agr;-methylstyrene or p-methylstyrene homo- or copolymer, b) a bromine-containing flame retardant, c) a UV absorber, d) a sterically hindered amine and e) an epoxidised fatty acid. This invention also relates to the use of the light stabiliser mixture consisting of components c), d) and e) for light-stabilising a styrene, &agr;-methylstyrene or p-methylstyrene homo- or copolymer finished with a bromine-containing flame retardant as well as to a process for the light-stabilisation thereof.
Styrene homo- and copolymers are often used as housings for electrical or electronic apparatus, such as computers or television sets, as packaging materials or also in the manufacture of automobiles.
Housings of electrical or electronic apparatus require flameproofing especially because electrostatic charges, bad electrical contacts or separating electrical connections may start a fire. Bromine-containing flame retardants have been found to be particularly suitable in this case.
When flameproofing housings it is often important, for aesthetic reasons, that the flame retardants cause as little discoloration as possible and that this discoloration does not increase under the influence of light and heat during use. This often requires the use of a UV/light stabiliser or UV absorber.
The light-stabilisation of styrene-containing polymers with sterically hindered amines and UV absorbers has been known for a long time and has been described, inter alia, by N. D. Searle et al. in J. Polym. Sci.: Part A: Polym. Chem., Vol. 27, 1341-1357 (1989). The light-stabilisation of flameproofed styrene polymers/copolymers is described, inter alia, by S. D. Landry et al. in Annual Technical Meeting of the Society of Plastic Engineers, New Orleans May 9-13, 1993 as well as, by the same authors, in a company publication of the Ethyl Corporation 8000 GSRI AVE Baton Rouge, La. 70820.
Surprisingly, it has now been found that adding an epoxidised fatty acid to a UV absorber and a sterically hindered amine in styrene, &agr;-methylstyrene or p-methylstyrene homo- or copolymers finished with bromine-containing flame retardants results in an unexpected synergistic effect in light stability. In particular, it is possible to markedly reduce the discoloration of the finished polymer which takes place in the course of irradation.
In one of its aspects, this invention accordingly relates to a composition, comprising a) a styrene, &agr;-methylstyrene or p-methylstyrene homo- or copolymer, b) a bromine-containing flame retardant, c) a UV absorber, d) a sterically hindered amine and e) an epoxidised fatty acid.
Typical examples of homopolymers are polystyrene, poly(p-methylstyrene) and poly(&agr;-methylstyrene).
Preferred copolymers are those of styrene or &agr;-methylstyrene with dienes or acryl derivatives, for example styrene/butadiene, styrene/acrylonitrile, styrenelalkyl methacrylate, styrene/butadiene/alkyl acrylate and styrene/butadiene/methacrylate, styrene/maleic acid anhydride, styrene/acrylonitrile/methyl acrylate; mixtures of high impact strength of styrene copolymers and another polymer, for example a polyacrylate, a diene polymer or an ethylene/propylene/diene terpolymer; and block copolymers of styrene such as styrene/butadiene/styrene, styrene isoprene/styrene, styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/styrene.
Also important are graft copolymers of styrene or &agr;-methylstyrene, for example styrene on polybutadiene, styrene on polybutadiene/styrene or polybutadienelacrylonitrile copolymers, styrene and acrylonitrile (or methacrylonitrile) on polybutadiene; styrene, acrylonitrile and methyl methacrylate on polybutadiene; styrene and maleic acid anhydride on polybutadiene; styrene, acrylonitrile and maleic acid anhydride or maleic acid imide on polybutadiene; styrene and maleic acid imide on polybutadiene, styrene and alkyl acrylates or alkyl methacrylates on polybutadiene, styrene and acrylonitrile on ethylene/propylene/diene terpolymers, styrene and acrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile on acrylate/butadiene copolymers, as well as mixtures thereof with the copolymers cited above, for example the copolymer mixtures known as ABS, MBS, ASA or AES polymers.
The copolymers can be obtained as random copolymers or as block copolymers. Mixtures or random copolymers and block copolymers may also be obtained.
Polybutadiene-modified polystyrenes are often used for housings of electrical or electronic apparatus. These polystyrene types are known as impact-modified polystyrene. These are particularly preferred within the scope of this invention. A particularly preferred modification are acryl/butadiene/styrene copolymers (ABS).
Bromine-containing flame retardants are mentioned, inter alia, in Gächter/Müller Taschenbuch der Kunststoffadditive, Carl Hanser Verlag, 1983, pages 561-564.
To be mentioned as examples are: decabromodiphenyl oxide, octabromodiphenyl oxide, tetrabromodiphenyl oxide, tetrabromobisphenol A, hexabromocyclododecane, bis(tribromophenoxy)ethane, tribromophenol, ethylene-bis-tetrabromophthalimide, tetrabromobisphenol A polycarbonate oligomer, polystyrene bromide, tetrabromobisphenol A epoxy oligomer, ethylene-bis-pentabromodiphenyl, tris(tribromophenoxy)triazine.
Preferred flame retardants are ethylene-bis-pentabromodiphenyl and ethylene-bis-tetrabromophthalimide.
The flame retardants can be added in the conventional known amounts of e.g. 1 to 30% by weight, preferably of 5 to 20% by weight, based on the polymer.
Heavy metal oxides may be used as so-called synergists (Gächter/Müller Taschenbuch der Kunststoffadditive, Carl Hanser Verlag, 1983, pages 564-565). These are preferably Sb
2
O
3
or Sb
2
O
5
. The heavy metal oxides are normally used in an amount of 0.5 to 10% by weight, preferably of 1 to 5% by weight, based on the polymer.
The flame retardants are known and are commercially available from different producers.
Examples of UV absorbers c) are:
2.1. 2-(2′-Hvdroxyphenyl)benzotriazoles, for example 2-(2′-hydroxy-5′-methylphenyl)-benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl) benzotriazole, 2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3′,5′-ditert-butyl-2′-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chloro-benzotriazole, 2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole, 2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole, 2-(3′,5′-bis-(a,a-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)-carbonylethyl]-2′-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxy-carbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole, 2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2′-methylene-bis-[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol]; the transesterification product of 2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazole wit h polyethylene glycol 300; [R—CH
2
CH
2
—COO—CH
2
CH
2
&Brketclosest;
2
where R=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl, 2-[2′-hydroxy-3&pri
Ciba Specialty Chemicals Corporation
Hall Luther A. R.
Stevenson Tyler A.
Yoon Tae H.
LandOfFree
Light-stabilized flameproof styrene homopolymers and copolymers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Light-stabilized flameproof styrene homopolymers and copolymers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Light-stabilized flameproof styrene homopolymers and copolymers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2455070