# US 4,392,804 A · Solid stating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,392,804 A - Document ID: US4392804A - Status: Granted - Kind: A - Application number: 06/299,283 - Filed: 1981-09-04 - Granted: 1983-07-12 - Earliest claimed: 1981-09-04 - Assignees: The Continental Group, Inc. - Inventors: Joan C. Pushee; Ieuan L. Harry; Martin H. Beck; Suppayan M. Krishnakumar - Web page: https://patentgrep.com/patent/US4392804A ## CPC - C08G 63/80: Solid-state polycondensation - B29B 7/86: for working at sub- or superatmospheric pressure {(B01F33/70 takes precedence)} - B29B 13/021: {Heat treatment of powders} - B29B 17/00: Recovery of plastics or other constituents of waste material containing plastics; ({volume reduction of waste plastics, e.g. by mechanical compacting or melting disposal of solid waste B09B;} chemical recovery C08J11/00) - B29C 45/72: Heating or cooling - B29C 48/287: {Raw material pre-treatment while feeding (B29C48/78 takes precedence)} - B29C 48/295: in gaseous form - B29C 48/793: upstream of the plasticising zone, e.g. heating in the hopper - B29C 48/022: {characterised by the choice of material} - B29C 48/09: Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels - B29K 2067/00: Use of polyesters {or derivatives thereof}, as moulding material - Y02W 30/62: Plastics recycling; Rubber recycling - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS - B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS - 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 - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT ## Abstract This relates to the increasing of the intrinsic viscosity of resins, particularly PET, by effecting a solid state polymerization of the resin. More particularly, the solid stating is effected in conjunction with an injection or extrusion unit wherein after having the IV of the resin increased, the heated resin may be fed dry into an injection unit thereby utilizing the heat of the heated resin to reduce heating cost. The solid state polymerization is effected by heating the resin in the presence of either a vacuum or an inert gas such as nitrogen. ## Claims ### Claim 1 An injection molding system comprising a particulate PET supply source, an extruder, and an injection mold, a supply line between said supply source and said extruder, a housing defining a chamber in which the particulate resin is temporarily stored in isolated condition along said supply line, and means associated with said chamber for effecting solid stating of particulate PET flowing in said housing to raise the intrinsic viscosity of the particulate resin in advance of particulate resin flow from said chamber to said extruder. ### Claim 2 (depends on 1) An injection molding system according to claim 1 wherein said means for effecting solid stating includes heater means for heating PET particles to a solid stating reaction temperature, and gaseous flow means for effecting the removal of products of condensation polymerization. ### Claim 3 (depends on 2) An injection molding system according to claim 2 wherein said heater means is operative to heat PET particles to an average temperature on the order of 180.degree. C. ### Claim 4 (depends on 2) An injection molding system according to claim 2 wherein said heater means is operative to heat PET particles to an average temperature on the order of 180.degree. C. with said temperature ranging from 172.degree. C. to 185.degree. C. ### Claim 5 (depends on 2) An injection molding system according to claim 2 wherein said heater means is operative to heat PET particles to a temperature ranging from 172.degree. C. to 230.degree. C. ### Claim 6 (depends on 2) An injection molding system according to claim 2 wherein said heater means is RF heater means. ### Claim 7 (depends on 2) An injection molding system according to claim 2 wherein said gaseous flow means are vacuum producing means. ### Claim 8 (depends on 2) An injection molding system according to claim 2 wherein said gaseous flow means are vacuum producing means providing a vacuum on the order of 0.1 mm of mercury. ### Claim 9 (depends on 2) An injection molding system according to claim 2 wherein said gaseous flow means is inert gas flow means. ### Claim 10 (depends on 2) An injection molding system according to claim 2 wherein said gaseous flow means is nitrogen flow means. ### Claim 11 (depends on 1) An injection molding system according to claim 1 wherein said means for effecting solid stating includes a chamber, and flow control valve means at opposite ends of said chamber for delivering PET particles to said chamber at a level of intrinsic viscosity and delivering PET particles from said chamber at an increased level of intrinsic viscosity. ### Claim 12 Apparatus for increasing the intrinsic viscosity of PET, said apparatus comprising a particulate PET supply source, a receptacle for receiving particulate PET having an increased intrinsic viscosity, a supply line between said supply source and said receptacle, a housing defining a chamber for receiving and temporarily storing PET particles, heater means for heating the temporarily stored PET particles in isolated relation along said supply line within said chamber to effect a solid stating reaction of the PET particles flowing in said chamber to raise the intrinsic viscosity of the particulate PET before the PET particles are discharged from said chamber into said receptacle, and gaseous flow means connected to said chamber for removing the products of condensation polymerization. ### Claim 13 (depends on 12) Apparatus according to claim 12 wherein said heater means is RF heater means. ### Claim 14 (depends on 12) Apparatus according to claim 12 wherein said gaseous flow means are vacuum producing means. ### Claim 15 (depends on 12) Apparatus according to claim 12 wherein said gaseous flow means is nitrogen flow means.