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
2002-02-01
2004-01-20
Buttner, David J. (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...
C525S413000, C525S462000, C528S370000, C528S372000, C528S417000, C528S421000, C239S024000, C473S569000, C030S322000, C030S324000, C030S345000, C606S234000
Reexamination Certificate
active
06680359
ABSTRACT:
This invention relates generally to polymeric thermoplastic moldable compositions comprising poly(alkylene carbonates) which are useful in manufacturing articles including, but not limited to articles which may be manipulated and shaped by their users but regain their shape after distortion.
BACKGROUND OF THE INVENTION
Plastics manufactured today for use in articles such as children's toys and products which are placed in the mouth of the user either by design or action of the user pose certain health risks to the user, i.e., toxicity to the user from the polymers used to manufacture the article or toxicity from the processing aids used in the manufacturing of the polymeric article. In addition to the direct health risks to the user of these articles, there may be environmental hazards as well.
Polyvinyl chloride (PVC) is a commonly used polymeric material for the manufacture of children's toys and products. Polyvinyl chloride is also used in a number of other articles such as toothbrushes, toys, eating utensils, food storage containers, and dinnerware. Since softness which is the ability of a compound to bend, yield or become flexible when gentle pressure is applied, (i.e., having a glass transition temperature from about 15° C. or higher) is not an inherent property of PVC as well as other plastics, and since softness is a desired component for many of the articles made from PVC or other plastics, especially articles intended to be used by children, there is a need to add this property to the PVC. A common way of addressing this need is to add or employ a processing aid in the manufacturing process. Processing aids generally are added in the manufacturing of polymeric materials to increase flexibility, workability and extrudablitiy of the end product. In the case of PVC, processing aids generally referred to as plasticizers and exemplified by a class of compounds known as phthalates are used to add softening and flexibility properties to the end product made from PVC. Phthalates are alkyl esters of isomeric benzenedicarboxylic acids. However, these compounds (phthalates) have been linked to liver and kidney damage. Also, it has been reported in the literature that when used as a processing aid in the preparation of products made of PVC, the phthalates can be leached out of the PVC product. This leaching occurs when the PVC product containing the phthalates comes in contact with human saliva. This situation is of particular concern with products that are intended for use by children, especially children under the age of three.
From an environmental standpoint, the PVCs currently on the market pose health and environmental hazards when the products are eventually destroyed or eliminated through combustion or thermal decomposition. When PVCs are burned, they decompose in to chlorinated chemicals, chlorine and hydrochloric acid, which are toxic. Chlorine and hydrochloric acid are corrosive and the chlorinated compounds are often flammable, as well as corrosive, and destructive to the protective stratosphere which is implicated in global warming and increased cancer hazards due to excessive UV exposure.
Plastics currently on the market, which add potentially toxic plasticizer additives, do not have low glass transition temperatures allowing for more flexibility and softness as desired when a user is handling, i.e., softening them from contact with the body caused by body heat. These plastics also do not offer abrasion resistance, durability, brilliant coloring and weather resistance in one product.
Therefore, there exists a need in the art for a polymeric material, free of toxic plasticizers, having softness, flexibility, abrasion resistance, durability, coloring and weather resistance properties, and useful in the manufacturing of products which may be placed in the mouth either by design or by the action of the user. A need especially exists for a polymeric material having the aforementioned properties for the manufacturing of products used by children, particularly children under three years of age.
PRIOR ART DISCUSSION
Harris, U.S. Pat. No. 4,686,273 discloses a process for modifying and increasing the molecular weight of a poly(alkylene carbonate) polyahl, with at least one modifier having a plurality of moieties that are reactive with the carbonate and/or acting hydrogen moieties of the poly(alkylene carbonate) polyahl at elevated temperatures and at a pressure at which at least one compound other than a monoalkylene glycol which compound is at least as volatile as a tetraethylene glycol is removed in the gaseous state from the poly(alkylene carbonate) polyahl.
Rokicki, U.S. Pat. No. 4,943,677 discloses a process for preparing poly(alkylene carbonates) of controlled molecular weight by copolymerizing carbon dioxide and one or more oxirane compounds using zinc polycarboxylate catalyst in the presence of a sterically hindered organic proton donor.
Carroll, et al., U.S. Pat. No. 4,960,862 discloses a process for regenerating metallo-organic catalyst used in copolymerizing carbon dioxide with epoxides to form poly(alkylene carbonates).
Maximovich, U.S. Pat. No. 3,896,090 discloses a process for preparing polycarbonates from an alkylene carbonate and monomeric polyols.
Myers, U.S. Pat. No. 4,686,276 discloses a process for preparing poly(alkylene carbonate) polymer by the reaction of alkylene oxide with carbon dioxide and/or an alkylene carbonate at an elevated temperature and pressure.
Sun, U.S. Pat. No. 4,789,727 discloses a process for preparing poly(alkylene carbonates) by the reaction of alkylene oxides with carbon dioxide in the presence of a catalyst comprising zinc carboxylate and or diepoxide.
Kuyper, et al., U.S. Pat. No. 4,826,887 discloses a process for preparing polycarbonates by reacting an epoxy compound with carbon dioxide at 40° to 200° C. and 2 to 40 bar in the presence of a catalyst.
Bezwada, et al., U.S. Pat. No. 5,037,950 discloses copolymers comprising p-dioxanone and poly(alkylene carbonates) useful in fabrication of sterile surgical articles and bioabsorbable coatings for sutures.
Stevens, U.S. Pat. No. 3,248,415 discloses a process for preparing high molecular weight polycarbonates from carbon dioxide and 1,2 epoxides.
While the foregoing discloses a number of processes for preparing the poly(alkylene carbonates) as well as a number of different uses for poly(alkylene carbonates), there is no art which addresses the use of this class of polymers for applicant's invention. Therefore, there remains a need in the art for this particular application of poly(alkylene carbonates).
SUMMARY OF THE INVENTION
The present invention offers a polymeric thermoplastic moldable composition comprising polyalkylene carbonates useful in manufacturing of products which may be manipulated and shaped by the user but regain their shape after distortion. Accordingly, it is an object of the present invention to provide a moldable composition which is non-toxic. It is an object of the present invention to provide a moldable composition which has the properties of softness, flexibility, abrasion resistance, durability, coloring and weather resistance, polymeric thermoplasticity, elastomeric with recovery and oil resistance. It is a further object of the present invention to provide products which are made from the polymeric thermoplastic moldable composition of the present invention which are safe when placed in the human mouth and exposed to human saliva. It is a still further object of the present invention to provide a method of manufacturing products which may be manipulated and shaped by the user but will regain their shape after distortion wherein the method is safe and cost-effective. It is a still further object of the present invention to provide a polymeric thermoplastic moldable composition which is useful in the manufacturing of articles intended for use by children especially, but not limited to children under the age of three.
DEFINITION OF TERMS
The term “manipulated and shaped by the user” is defined as the distortion of the article from its intende
Buttner David J.
McDermott & Will & Emery
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