Process for forming plastic articles

DETAILED DESCRIPTION What is claimed is: 1.
A process of forming decomposition-free, substantially fused, clear, flexible plastic shaped articles comprising the sequential steps of (1) compressing in a compressing device a resinous powder having lamellar crystalline nonspherulitic morphology into a substantially unoriented briquette having green strength, (2) removing said briquette from the compressing device and placing said briquette in a forging press wherein lubrication is provided between the contacting surfaces of the briquette and said forging press to effect plug flow, and (3) forging said briquette into a shaped article while maintaining said briquette at a temperature between the alpha-transition temperature and the melting point of said resinous powder.
2.
The process of claim 1 wherein the briquette is heated to a temperature of from about the alpha-transition temperature to less than the melt temperature of said resinous powder, after being removed from said compressing device and prior to being placed in said forging press.
3.
The process of claim 2 wherein said resinous powder is a crystalline vinylidene chloride polymer.
4.
The process of claim 2 wherein said resinous powder is polyethylene.
5.
The process of claim 2 wherein said resinous powder is polypropylene.




Description:
BACKGROUND There is a need for a fast predominantly solid phase process for forming articles directly from powdered thermoplastic resin materials.
Such powder formed parts can be made at a lesser expense than a comparable part made by either an injection molding technique or a conventional vacuum forming process.
The reasons for the favorable economics of powder formed parts are elimination of a pelletizing step, absence of excess scrap, a reduced cooling cycle and a more efficient material utilization.
Further, a process having relatively short heat cycle times is especially desired when fabricating thermally unstable resinous powders, such as the crystalline vinylidene halide polymers