GB580855A - Removal of stresses from thermoplastic resin articles - Google Patents

Removal of stresses from thermoplastic resin articles

Info

Publication number
GB580855A
GB580855A GB2072/44A GB207244A GB580855A GB 580855 A GB580855 A GB 580855A GB 2072/44 A GB2072/44 A GB 2072/44A GB 207244 A GB207244 A GB 207244A GB 580855 A GB580855 A GB 580855A
Authority
GB
United Kingdom
Prior art keywords
articles
liquid
article
elevated temperature
thermoplastic resins
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
GB2072/44A
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.)
CHARLES HAMPDEN CROOKS
HELMUT SILBER
WILLIAM ANTHONY GREENWOOD
Imperial Chemical Industries Ltd
Original Assignee
CHARLES HAMPDEN CROOKS
HELMUT SILBER
WILLIAM ANTHONY GREENWOOD
Imperial Chemical Industries Ltd
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 CHARLES HAMPDEN CROOKS, HELMUT SILBER, WILLIAM ANTHONY GREENWOOD, Imperial Chemical Industries Ltd filed Critical CHARLES HAMPDEN CROOKS
Publication of GB580855A publication Critical patent/GB580855A/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
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • 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
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
    • B29C71/02—Thermal after-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00009—Production of simple or compound lenses

Landscapes

  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Abstract

Removing internal stresses from articles of bubble free natural thermoplastic resins such as shellac by treating said articles in an inert liquid at an elevated temperature, said liquid having a density differing from that of the article by not more than 0.1 grams per c.c. at said elevated temperature and then cooling said article slowly and uniformly. Plasticizers, modifying agents, dyes and/or fillers may be present in the article composition. It is preferred that the articles should be heated to within 10 DEG C. of the softening point of the composition from which they are made. A stirring or oscillating system for the liquid and a clamping device for the article are usually employed. The invention is particularly useful in the treatment of blanks and preforms which are subsequently fabricated into optical components. Specification 450,305, [Group IV], is referred to.ALSO:Internal stresses are removed from bubble-free articles composed essentially of thermoplastic resins (including partly-natural partly-synthetic thermoplastic resins such as cellulose acetate) by heating said articles in an inert liquid at an elevated temperature, said liquid having a density differing from that of the articles by not more than \sB 0.1 grams per c.c. at said elevated temperature and then cooling said articles slowly and uniformly. Specified resins are polymethyl methacrylate, styrene, shellac and cellulose acetate. A specified inert liquid is glycerol. It is preferred that the articles should be heated to within \sB 10 DEG C. of the softening point of the composition from which they are made and that they should be cooled slowly and uniformly to room temperature while still in the said inert liquid. To ensure even heating and cooling, a suitable stirring or circulating system for the liquid is necessary and the movement of the articles in the bath is restricted by some suitable device such as clamps. The invention is particularly useful in the treatment of blanks and preforms of transparent thermoplastic resins which are subsequently fabricated into optical components. Plasticisers, modifying agents, dyes and/or fillers may be present in the article compositions. In an example, a polymethylmethacrylate, bubble-free preform of a circular double convex lens having internal stresses was clamped in a stirred bath of glycerol at 100 DEG C., and after one hour slowly cooled to 25 DEG C. The internal stresses were found to have been removed. Specification 450,305 is referred to.
GB2072/44A 1944-02-04 1944-02-04 Removal of stresses from thermoplastic resin articles Expired GB580855A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB251955X 1944-02-04

Publications (1)

Publication Number Publication Date
GB580855A true GB580855A (en) 1946-09-23

Family

ID=10223768

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2072/44A Expired GB580855A (en) 1944-02-04 1944-02-04 Removal of stresses from thermoplastic resin articles

Country Status (2)

Country Link
CH (1) CH251955A (en)
GB (1) GB580855A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989003297A1 (en) * 1987-10-06 1989-04-20 Integrated Fluidics, Inc. Method of bonding plastics

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1149884B (en) * 1955-05-06 1963-06-06 Siemens Ag Process for the heat treatment of molded articles consisting of non-hardenable polymers, in particular electrical insulating molded articles
DE1126587B (en) * 1956-07-06 1962-03-29 Organico S A Device for the production of solid granulates from molten high polymers
DE1479157B1 (en) * 1961-01-07 1970-03-19 Bayer Ag Post-heat treatment process for workpieces made of high molecular weight, thermoplastic polycarbonates
DE1186614B (en) * 1961-09-06 1965-02-04 Continental Gummi Werke Ag Process for the production of bodies made of rubber with reinforcement inserts made of linear polymers that shrink in the heat, in particular of air suspension bellows

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989003297A1 (en) * 1987-10-06 1989-04-20 Integrated Fluidics, Inc. Method of bonding plastics

Also Published As

Publication number Publication date
CH251955A (en) 1947-11-30

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