Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-04-03
2002-03-12
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C521S040000, C525S461000, C525S462000, C524S401000
Reexamination Certificate
active
06355739
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a high performance resin composition. More particularly, it relates to a resin composition reclaimed from compact disk waste with improved mechanical characteristics.
2. Description of the Related Arts
At present, more than about 1.2 billion optical recording disks (i.e., compact disks) are produced yearly in Taiwan. A large quantity of polycarbonate wastes are produced in injection molding of compact disks, and a large amount of waste disks are produced because of defects. These disk wastes contain brittle components added in order to reduce birefringence of the disks. Thus, the disk wastes are low in impact resistance and have poor mechanical characteristics compared with a general engineering molded grade material. Thus, these materials cannot be reused for other high-quality moldings by directly re-processing or blending with other polymers. For the most part, these disk wastes are not recycled.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to obtain from compact disk waste a reclaimed resin material with a mechanical strength sufficient for use in a general molded product.
To attain the above object, a resin reclaimed from an optical recording disk comprising polycarbonate (hereinafter referred to as PC) as a primary component is added with a coupling agent in order to increase the molecular weight and the mechanical strength by an in-situ coupling reaction. Optionally, a compatible resin such as a low-priced thermoplastic resin, engineering plastic grade PC or waste thereof, or recycled bottle grade PC is added to improve the mechanical strength to an extent comparable to that of engineering plastic. Thereby, a resin material of high performance relative to cost can be obtained.
The resin material of the present invention provides improved mechanical characteristics. In particular, the impact value can be improved. Thus, the usage of the recycled resin material can be considerably expanded. In addition, because the optical recording disk material has excellent flowability, the resin material of the present invention is superior in processibility.
DETAILED DESCRIPTION OF THE INVENTION
The reclaimed resin material of the present invention is made by combining the compact disk waste with a coupling agent containing two or more functional groups reactive with terminal hydroxy groups of polycarbonate. Thus, the molecular weight and the mechanical characteristics thereof can be improved by an in-situ coupling reaction when proceeding extrusion of the resin material.
Furthermore, the toughness of the reclaimed resin material is increased by combining the compact disk waste with a compatible resin such as, for example, a low-priced thermoplastic resin (ABS, MBS, PBT, PET, etc.), engineering plastic grade PC or waste thereof, recycled bottle grade PC, and the like.
The reclaimed resin material can further include a flame retardant or other conventional additives such as reinforced fiber to improve its properties.
According to a first embodiment of the invention, there is provided a resin composition reclaimed from compact disk waste comprising (a) compact disk waste comprising polycarbonate as a primary component; and (b) 0.1-15 wt %, based on the weight of the compact disk waste, of a coupling agent containing two or more reactive functional groups.
According to a second embodiment of the invention, there is provided a resin composition reclaimed from compact disk waste comprising (a) 35-95 parts by weight of compact disk waste comprising polycarbonate as a primary component; (b) 65-5 parts by weight of an impact-resistant thermoplastic resin; and (c) 0.1-15 wt %, based on the total weight of the component (a) and (b), of a coupling agent containing two or more reactive functional groups.
According a third embodiment of the invention, there is provided a resin composition reclaimed from compact disk waste comprising (a) 30-90 parts by weight of compact disk waste comprising polycarbonate as a primary component; (b) 70-10 parts by weight of engineering plastic grade polycarbonate or waste thereof, or recycled bottle grade polycarbonate; and (c) 0.1-15 wt %, based on the total weight of the component (a) and (b), of a coupling agent containing two or more reactive functional groups.
In accordance with the present invention, any suitable coupling agents having two or more functional groups reactive with hydroxy groups may be used. Such coupling agents include, for example, anhydrides, isocyanates, epoxides, and urethanes.
Examples of suitable anhydride coupling agents include pyromellitic dianhydride (PMDA), 3,3′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA), 3,3′, 4,4′-biphenyl tetracarboxylic dianhydride (BPDA), terphenyl tetracarboxylic dianhydride (TPDA), 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), 1,1-bis(3,4-dicarboxyphenyl anhydride)-1-phenyl-2,2,2-trifluoroethane (3FDA), 9,9-bis(trifluoromethyl)-2,3,6,7-xanthene tetracaboxylic dianhydride (6FCDA), and trimellitic anhydride (TMA).
Examples of suitable isocyanate coupling agents include tris(2-carboxylethyl) isocyanate, diphenylmethane-4,4′-diisocyanate (MDI), polymethylenephenylene isocyanate (PMPI), hexamethylene diisocyanate, toluene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), 4,6′-xylene diisocyanate (XDI), 3,3′-dimethyldiphenyl 4,4′-diisocyanate (TDDI), para-phenylene diisocyanate (PPDI), 3,3′-dimethyl-diphenylmethane 4,4′-diisocyanate (DMMDI), and dianisidine diisocyanate (DADI).
Examples of suitable epoxide coupling agents include epoxidized styrenic copolymers, epoxidized olefinic copolymer, glycerol polyglycidyl ether, diglycidyl terephthalate, diglycidyl orthophthalate, and pentaerythritol polyglycidyl ether.
The impact-resistant thermoplastic resins useful in the present invention include those low-priced thermoplastic resins that can improve toughness to polycarbonate. Some examples for such thermoplastic resins include acrylonitrile-butadiene-styrene copolymer (ABS), methacrylate-butadiene-styrene copolymer (MBS), acrylonitrile-acrylic rubber-styrene copolymer (AAS), acrylonitrile-ethylene propylene rubber-styrene copolymer (AES), acrylonitrile-chlorinated polyethylene rubber-styrene copolymer (ACS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), acrylic rubber, styrene-butadiene-styrene block copolymer (SBS), and styrene-ethylented-butadiene-styrene elastomer (SEBS).
The reclaimed resin material according to the invention can be reprocessed in the same way as the original resins to produce any of a variety of moldings in standard machines such as extruders or injection molding machines. The moldings obtained can then be used for a wide range of applications, such as in the electronic products or as camera casings.
Further, reclaimed resin material according to the invention may be provided, before or during processing, with the usual flame retardants to obtain flame resistance products; or they can be provided with reinforced fiber or fillers to obtain molded products having high stiffness, impact strength, and heat resistance. Other conventional additives can be added to the resin material, including antioxidants, heat stabilizers, lubricants, etc.
REFERENCES:
patent: 5807932 (1998-09-01), Pfaendner et al.
Kao Hsin-Ching
Lui Wen-Ling
Tsai Shih-Jung
Dawson Robert
Industrial Technology Research Institute
Peng Kuo-Liang
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