GB1566750A - Creación de Inventos y Patentes con Inteligencia Artificial

GB1566750A – Method of removing thermoset polymers from articles
– Google Patents

GB1566750A – Method of removing thermoset polymers from articles
– Google Patents
Method of removing thermoset polymers from articles

Download PDF
Info

Publication number
GB1566750A

GB1566750A
GB52760/76A
GB5276076A
GB1566750A
GB 1566750 A
GB1566750 A
GB 1566750A
GB 52760/76 A
GB52760/76 A
GB 52760/76A
GB 5276076 A
GB5276076 A
GB 5276076A
GB 1566750 A
GB1566750 A
GB 1566750A
Authority
GB
United Kingdom
Prior art keywords
coils
article
laminated core
molten compound
articles
Prior art date
1975-12-23
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
GB52760/76A
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.)

CBS Corp

Original Assignee
Westinghouse Electric Corp
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.)
1975-12-23
Filing date
1976-12-17
Publication date
1980-05-08

1976-12-17
Application filed by Westinghouse Electric Corp
filed
Critical
Westinghouse Electric Corp

1980-05-08
Publication of GB1566750A
publication
Critical
patent/GB1566750A/en

Status
Expired
legal-status
Critical
Current

Links

Espacenet

Global Dossier

Discuss

Classifications

H—ELECTRICITY

H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER

H02K—DYNAMO-ELECTRIC MACHINES

H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines

H02K15/0006—Disassembling, repairing or modifying dynamo-electric machines

C—CHEMISTRY; METALLURGY

C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR

C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR

C09D9/00—Chemical paint or ink removers

C09D9/005—Chemical paint or ink removers containing organic solvents

Description

( 21) Application No 52760/76
( 31) Convention Application IP ( 32) Filed 23 Dec 1975 in ( 33) United States of America ( 44) Complete Specification pi ( 51) INT CL’ C 11 D 7/50 ( 52) Index at acceptance C 5 D 1 811 D 1 81 IB 2 ( 22) Filed 17 Dec 1976 No 643720 (US) jublished 8 May 1980 ( 54) METHOD OF REMOVING THERMOSET POLYMERS FROM ARTICLES ( 71) We, WESTINGHOUSE ELECTRIC CORPORATION of Westinghouse Building, Gateway Center, Pittsburg, Pennsylvania, United States of America, a company organised and existing under the laws of the Commonwealth of Pennsylvania, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described
in and by the following statement: –
This invention relates to a method of removing thermoset polymers from articles.
Defective motors are repaired by removing the conductor coils from the magnetic iron core and rewinding the core The coils are, of course, insulated, and are usually held in place by varnish impregnant, wedges, and end blocks This material, which consists largely of thermoset resins, must be removed or destroyed in order to remove the coils The usual practice is to bum out the thermoset resins.
Burning, however, produces pollutants, uses energy, and leaves a char which is difficult to remove.
An alternative procedure is to immerse the motor in a stripper composition Commercial strippers, however, swell the resin without destroying it, and a swelled resin may be no easier to remove than an unswelled resin.
According to the present invention a method of removing a thermoset polymer from an article comprises immersing the article in a molten compound having the general formula O C where N is an integer from 5 to 7.
Preferably «n» is 5, because that compound, caprolactam, is less expensive and more readily available than other lactams If «n» is below 5, the lactam is too low boiling and if «n» is more than 7, the lactam is less effective and too expensive.
Compounds which become lactams at the temperature of use, such as amino-caproic acid, are considered to be equivalent and may also be used Mixtures of lactams are also contemplated.
It has thus been found that thermoset polymers including aromatic ethers can be effectively removed from articles by immersing the articles in a molten lactam To the best of our knowledge, aromatic ethers are not attacked by any other known stripper.
The lactams do not merely swell the resin, but rather attack the resin by breaking the polymers into smaller molecules which are soluble, whereas the polymer is not.
The lactams produce very little pollution since vapors are condensed and returned.
They are apparently of low toxicity and do not attack common metals such as iron, copper, and aluminum, nor do they attack glass or cellulose Also, they have had no apparent effect on the interlaminar insulation of electrical equipment They work rapidly, in most cases requiring only a few hours to strip a motor stator or rotor, and use less energy than does burning the insulation.
The strippers will attack phenolics, polyesters, epoxies, and diphenyl oxide resins, and it seems a fair assumption that they will attack other thermoset resins the strippers have not yet been tested on However, it is especially useful in stripping diphenyl oxide (i e, aromatic ether) resins as they are not attacked, as far as is known, by any other stripper The thermoset aromatic ether polymers which are attacked by the stripper are polymers having an ether linkage in the backbone of the polymer chain Examples include the polymer sold by Westinghouse Electric Corporation under the trademark «Doryl», or the polymer sold by Ciba-Geigy under the trademark «Xylok», which contain the repeating unit CH «‘ The lactam must be molten at the temperature of use Caprolactam melts at 68690 C, but a temperature of 200 to 2500 C is PATENT SPECIFICATION ( 11) 1 566 750 1,566,750 preferred as it is faster yet not so high to cause problems with vapors.
The object to be stripped is immersed into the stripper until it has been observed to be stripped If the object is a motor stator or rotor, it is first prepared by sawing off the ends of the coils If the rotating apparatus is form wound it may not be necessary to cut the ends, but mush wound apparatus must be cut at at least one end.
In order that the invention can be more clearly understood, convenient embodiments thereof will now be described, by way of example, with reference to the accompanying drawings in which:
Figure 1 is a cross-sectional view of a motor stator immersed in a lactam stripper, and Figure 2 is a flow chart of the process of this invention.
In Figure 1 coils 1 of stator 2 have been cut at 3 The other end of the coils 4 has not been cut to provide something to grasn while pulling the coils from laminated core 5 The stator is immersed in stripper 6 held in tank 7 The length of time required to strip an article depends upon the accessability of the polymer to attack, its age, thickness, and degree of cure, but about 1-1/2 to about 3 hours is typical, although as long as 6 hours may be required to strip a motor coil.
The stripped object is removed, drained,’ cooled, and washed with water or other common solvents Figure 2 shows the steps involved in removing coils from a motor stator or rotor using the process of this invention.
In Figure 2, steps 3 and 4 can be reversed.
While the stripper was especially designed for stripping motors, it can also be used to strip generators, transformers, and other electrical conductors insulated with thermoset resins The stripper can also be used on laminates to dete’rmine the amount of filler they contain, to clean objects contaminated with resins, or for other purposes.
The stripper may be renewed from time to time by the addition of fresh stripper It may also be filtered occasionally to remove suspended particles.
The invention will now be illustrated with reference to the following Example:
EXAMPLE
Five glass-reinforced laminates, one based on a phenolic resin, one on a polyester resin, one on an epoxy resin, one on a diphenyl oxide resin, and one on an unknown thermosetting resin were placed in caprolactam for three hours at 240 to 2501 C All of the labindates were completely delaminated and the resin removed from the glass.

Claims (1)

WHAT WE CLAIM IS:-
1 A method of removing a thermoset polymer from an article comprising immersing the article in a molten compound having the general formula where N is an integer from 5 to 7.
2 A method according to claim 1, wherein n = 5.
3 A method according to claim 1 or 2, wherein the thermoset polymer is an aromatic polyether.
4 A method according to claim 1, 2 or 3, wherein the molten compound is from 200 to 2500 C A method according to any of claims 1 to 4, wherein there are included the additional last steps of removing the article from the molten compound and cleaning the article.
6 A method according to any of claims 1 to 5, wherein the article is a rotating electrical apparatus having coils of insulated wire embedded in a laminated core.
7 A method according to claim 6, wherein there is included an initial step of severing at least one end of said coils.
8 A method according to claim 6 or 7, wherein ( 1) in either order, (a) the laminated core is removed from the lactam after the insulation of the coils have been destroyed and (b) the wire of said coils is removed from said laminated core; and ( 2) the laminated core is cleaned.
9 A method of removing coils from a motor stator or rotor substantially as described herein with particular reference to the accompanying drawings.
A method of delaminating glass-reinforced laminates substantially as described herein with particular reference to the foregoing Example.
RONALD VAN BERLYN.
Printed for Her Majesty’s Stationery Office, by the Courier Press, Leamington Spa, 1980 Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A IAY, from which copies may be obtained.

GB52760/76A
1975-12-23
1976-12-17
Method of removing thermoset polymers from articles

Expired

GB1566750A
(en)

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

US05/643,720

US4032362A
(en)

1975-12-23
1975-12-23
Method of stripping thermoset polymers with molten lactams

Publications (1)

Publication Number
Publication Date

GB1566750A
true

GB1566750A
(en)

1980-05-08

Family
ID=24582006
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB52760/76A
Expired

GB1566750A
(en)

1975-12-23
1976-12-17
Method of removing thermoset polymers from articles

Country Status (8)

Country
Link

US
(1)

US4032362A
(en)

JP
(1)

JPS5280331A
(en)

CA
(1)

CA1068200A
(en)

DE
(1)

DE2656972A1
(en)

FR
(1)

FR2336437A1
(en)

GB
(1)

GB1566750A
(en)

IT
(1)

IT1065512B
(en)

NL
(1)

NL7613263A
(en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

US4435221A
(en)

1982-07-30
1984-03-06
Phillips Petroleum Company
Process for cleaning metal surfaces of poly(arylene sulfide) deposits

Family Cites Families (4)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

US2939209A
(en)

1958-05-01
1960-06-07
Horizons Inc
Reconditioning of electric apparatus

US3185656A
(en)

1960-03-29
1965-05-25
Grace W R & Co
Preparation of linear polyureas utilizing a cyclic amide solvent

US3669740A
(en)

1968-11-05
1972-06-13
Teijin Ltd
Method of cleaning polyamide producing apparatus

US3764384A
(en)

1970-07-24
1973-10-09
Gaf Corp
Process for removing polyvinyl halide residues from processing equipment

1975

1975-12-23
US
US05/643,720
patent/US4032362A/en
not_active
Expired – Lifetime

1976

1976-11-24
CA
CA266,428A
patent/CA1068200A/en
not_active
Expired

1976-11-29
NL
NL7613263A
patent/NL7613263A/en
not_active
Application Discontinuation

1976-12-09
FR
FR7637155A
patent/FR2336437A1/en
not_active
Withdrawn

1976-12-16
DE
DE19762656972
patent/DE2656972A1/en
active
Pending

1976-12-17
GB
GB52760/76A
patent/GB1566750A/en
not_active
Expired

1976-12-21
JP
JP51152989A
patent/JPS5280331A/en
active
Pending

1976-12-22
IT
IT30777/76A
patent/IT1065512B/en
active

Also Published As

Publication number
Publication date

NL7613263A
(en)

1977-06-27

US4032362A
(en)

1977-06-28

CA1068200A
(en)

1979-12-18

FR2336437A1
(en)

1977-07-22

IT1065512B
(en)

1985-02-25

JPS5280331A
(en)

1977-07-06

DE2656972A1
(en)

1977-07-07

Información de contacto