# US 5,702,665 A · Process for heat treating thermoplastic containers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,665 A - Document ID: US5702665A - Status: Granted - Kind: A - Application number: 08/381,708 - Filed: 1995-01-31 - Granted: 1997-12-30 - Earliest claimed: 1995-01-31 - Inventors: Emery I. Valyi - Web page: https://patentgrep.com/patent/US5702665A ## CPC - B29C 49/642: {and shrinking of the preform} - B29C 49/6472: {in several stages} - B29C 49/06: Injection blow-moulding - B29C 2949/0715: the preform having one end closed - B29K 2067/00: Use of polyesters {or derivatives thereof}, as moulding material - B29K 2995/0041: Crystalline - Y10S 264/906: And heat-shrinking outside of mold including subsequent re-expanding of shrunken article using differential fluid pressure - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A process for preparing a thermoplastic container including the steps of providing a biaxially oriented, crystallized precontainer having a first contained volume, and further crystallizing the precontainer by applying heat thereto while the precontainer is substantially unconstrained, and forming a deformed precontainer having a second contained volume. Deformation of the precontainer is controlled by controllably closing the precontainer prior to further crystallizing and while the precontainer remains substantially unconstrained to create a predetermined increased air pressure therein, and reshaping the deformed precontainer into a final container shape. ## Claims ### Claim 1 A process for preparing a thermoplastic container, comprising the steps of: providing a biaxially oriented, crystallized precontainer having a first contained volume by expanding said precontainer from a tubular preform; selectively further crystallizing said precontainer by applying heat thereto while the precontainer is substantially unconstrained, including the step of protecting from heating those portions of the precontainer that have been deformed less than 2-fold in the course of expanding the preform to form said precontainer, and forming a deformed precontainer having a second contained volume; controlling deformation of the precontainer by closing the precontainer prior to further crystallizing in a manner permitting the controllable air escape from the precontainer and while the precontainer remains substantially unconstrained to create a predetermined increased air pressure in the deformed precontainer; reshaping the deformed precontainer by blow molding into a final container shape; wherein the increased air pressure in the deformed precontainer is controlled so as to provide said second contained volume of the deformed precontainer to be sufficiently close to the volume of the final container such that during reshaping, stresses are minimized, and wherein the deformation of the precontainer is controlled so as to obtain a size and shape capable of being transformed into a predetermined final shape without further substantial deformation by changing the shape of said crystallized precontainer in a blow mold into that of said container; and wherein the increased air pressure limits the amount of deformation of the precontainer and permits only symmetrical shrinking; and wherein said precontainer has a level of orientation, and wherein said second contained volume being defined by a shape such as to substantially maintain the level of orientation of the precontainer. ### Claim 2 (depends on 1) The process according to claim 1, further comprising the step of rotating the precontainer during the step of crystallizing for achieving substantially even heat distribution. ### Claim 3 (depends on 2) The process according to claim 2, further comprising the step of moving the precontainer through a heating device with said precontainer being substantially unconfined during the moving. ### Claim 4 (depends on 1) The process according to claim 1, wherein the deformed precontainer is reshaped by pressurizing the deformed precontainer in a reforming means. ### Claim 5 (depends on 4) The process according to claim 4, wherein the reforming means is a blow mold, the process further including the step of pressurizing the deformed precontainer to conform it to the configuration of the blow mold. ### Claim 6 (depends on 4) The process according to claim 4, wherein said precontainer is reshaped within 5 seconds of leaving said crystallizing step. ### Claim 7 (depends on 1) The process according to claim 1, wherein the thermoplastic is polyethylene terephthalate. ### Claim 8 (depends on 1) The process according to claim 1, wherein the precontainer is closed by means of a pressure relief valve comprising control means for the pressure retained in the precontainer. ### Claim 9 (depends on 1) A process according to claim 1, wherein the precontainer includes a bottom portion, and including the step of protecting the bottom portion from heating during said further crystallizing step.