GB884878A - Method of extruding thermoplastic resins - Google Patents

Method of extruding thermoplastic resins

Info

Publication number
GB884878A
GB884878A GB32589/60A GB3258960A GB884878A GB 884878 A GB884878 A GB 884878A GB 32589/60 A GB32589/60 A GB 32589/60A GB 3258960 A GB3258960 A GB 3258960A GB 884878 A GB884878 A GB 884878A
Authority
GB
United Kingdom
Prior art keywords
shear rate
extrusion
rate
super
die
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB32589/60A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of GB884878A publication Critical patent/GB884878A/en
Expired legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/05—Filamentary, e.g. strands
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/06—Rod-shaped
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
    • B29C48/10—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29K2027/00—Use of polyvinylhalogenides or derivatives thereof as moulding material
    • B29K2027/12—Use of polyvinylhalogenides or derivatives thereof as moulding material containing fluorine
    • B29K2027/18—PTFE, i.e. polytetrafluorethene, e.g. ePTFE, i.e. expanded polytetrafluorethene

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Abstract

A normally solid ethylene polymer having a density in the range of 0,95 to 0,97 g./c.c. or an interpolymer of tetrafluoroethylene and hexafluoropropylene containing 6 to 26% by wt. of combined hexafluoropropylene is extruded by heating and forcing through a die at a shear rate which is equal to or above the super extrusion shear rate. This latter shear rate is that at which the extrudate again becomes smooth as the shear rate is increased and is considerably higher than the critical extrusion shear rate at which surface fracture sets in. As the shear rate is increased to a rate several times the super extrusion shear rate, surface fracture gradually appears again. The preferred extrusion shear rate is between 1 and 3 times the super extrusion shear rate. As an example, linear polyethylene having a melt index (of 0,5 ASTM-D-1238-57-T) and an annealed density of 0,955 g./c.c. was extruded through a 1/8 inch circular die having a 0,6 inch land and 77 degrees included inlet angle using a 2 inch extruder. The super extrusion shear rate for this polymer at 235 DEG C. is 2500 sec-1, occurring at a pressure of 2600 psi. With the melt and the die at 235 DEG C, extrusion was commenced at a rate of 1 lb./hour and slowly increased, the surface of the extrudate being smooth, but at a rate of 3 lbs./hour the surface became very rough indicating that surface fracture was occurring. However, when the extrusion rate was increased to 45 lbs./hour, the extrudate became smooth again indicating that the super extrusion shear rate had been attained. Such an extrusion rate is equivalent to a shear rate of 2530 sec-1. The super extrusion shear rate is a function of the die temperature only, increasing as the die temperature increases; variation in the melt temperature has no effect, even when larger. A method of determining the super extrusion shear rate for a given polymer is described. Specifications 639,306 and 829,600 are referred to.
GB32589/60A 1959-09-23 1960-09-22 Method of extruding thermoplastic resins Expired GB884878A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US884878XA 1959-09-23 1959-09-23

Publications (1)

Publication Number Publication Date
GB884878A true GB884878A (en) 1961-12-20

Family

ID=22211659

Family Applications (1)

Application Number Title Priority Date Filing Date
GB32589/60A Expired GB884878A (en) 1959-09-23 1960-09-22 Method of extruding thermoplastic resins

Country Status (1)

Country Link
GB (1) GB884878A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5320798A (en) * 1993-02-17 1994-06-14 Exxon Chemical Patents, Inc. Method for processing polyolefins at high shear rates
CN113784829A (en) * 2019-05-30 2021-12-10 陶氏环球技术有限责任公司 Method for extruding Linear Low Density Polyethylene (LLDPE) without surface cracking in melt

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5320798A (en) * 1993-02-17 1994-06-14 Exxon Chemical Patents, Inc. Method for processing polyolefins at high shear rates
CN113784829A (en) * 2019-05-30 2021-12-10 陶氏环球技术有限责任公司 Method for extruding Linear Low Density Polyethylene (LLDPE) without surface cracking in melt

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