US4537734A
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Method for reducing the monomer content in acrylonitrile containing polymers
Assignee: Ardagh Metal Packaging Germany GmbH
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Filing: 1979-03-12
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Granted: 1985-08-27
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Expires: 1999-03-12
Abstract
Abstract The monomer content in acrylonitrile containing polymers, as for example bottles formed from acrylonitrile/styrene copolymer, is substantially reduced by applying ionizing radiation at conventional rates in low dosage levels.
Inventors
- 👤 Kennard H. Morganstern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:27
CPC Classifications
C; C08; C08J; C08J7/00; C08J7/12; C08J7/123; B; B29; B29B; B29B9/00; B29B9/16; B29C; B29C71/00; B29C71/04; C08F; C08F6/00; C08F6/006; B29C35/00; B29C35/02; B29C35/08; B29C35/0866; B29K; B29K2033/00; B29K2033/18; B29K2033/20; C08J2333/00; C08J2333/18; C08J2333/20; Y; Y10; Y10S; Y10S522/00; Y10S522/903; Y10S522/911
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
63 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein the polymer is not at or above its softening point during exposure to said ionizing radiation.
Claim 2
Independent Claim
63 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein the polymer is not at or above its softening point during exposure to said ionizing radiation.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the irradiation treatment is followed by an HCN outgassing treatment.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the residual acrylonitrile monomer is reduced by more than about 50% by weight.
Claim 5
Dependent Claim
20 words
The method of claim 3 wherein the said residual acrylonitrile content is reduced by at least about 90% by weight.
Claim 6
Dependent Claim
16 words
The method of claim 1 in which the source of ionizing radiation is an electron beam.
Claim 7
Dependent Claim
40 words
The method of claim 1 wherein said acrylonitrile polymer is selected from the group consisting of acrylonitrile homopolymers and copolymers of acrylonitrile with ethylenically unsaturated monomers selected from the group consisting of styrene, butadiene and methyl acrylate or other acrylates.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein the polymer treated is in solution or suspension form.
Claim 9
Dependent Claim
15 words
A method according to claim 1 wherein said dosage level is from about 0.1-1.5 megarads.
Claim 10
Dependent Claim
15 words
A method according to claim 1 wherein said dosage level is from about 0.05-0.5 megarads.
Claim 11
Dependent Claim
31 words
A method according to claim 1 wherein exposing the polymer to ionizing radiation is conducted in at least two exposures, the total of which does not exceed from about 0.05-2.0 megarads.
Claim 12
Independent Claim
124 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein said acrylonitrile polymer is a copolymer comprised of from 55-85% by weight (of the total polymer weight) of acrylonitrile alone or acrylonitrile and methacrylonitrile in amounts up to 16% by weight (of the total polymer weight) and one or more comonomers selected from the group consisting of styrene, alpha methylstyrene, alpha olefins of 2-6 carbon atoms, C 1 -C 4 akyl esters of acrylic and methacrylic acid, vinyl acetate, and C 1 -C 4 alkyl vinyl esters.
Claim 13
Independent Claim
124 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein said acrylonitrile polymer is a copolymer comprised of from 55-85% by weight (of the total polymer weight) of acrylonitrile alone or acrylonitrile and methacrylonitrile in amounts up to 16% by weight (of the total polymer weight) and one or more comonomers selected from the group consisting of styrene, alpha methylstyrene, alpha olefins of 2-6 carbon atoms, C 1 -C 4 akyl esters of acrylic and methacrylic acid, vinyl acetate, and C 1 -C 4 alkyl vinyl esters.
Claim 14
Dependent Claim
17 words
A method according to claim 11 wherein said polymer is in the form of a packaging material.
Claim 15
Independent Claim
61 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein said polymer is a formed bottle or jar comprised of 60-83% by weight acrylonitrile.
Claim 16
Independent Claim
61 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein said polymer is a formed bottle or jar comprised of 60-83% by weight acrylonitrile.
Claim 17
Dependent Claim
13 words
The method of claim 13 wherein the article is a soft drink bottle.
Claim 18
Independent Claim
82 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer comprising, providing the polymer to be treated in the form of a ground resin or pellet, exposing said polymer while in said ground resin or pellet form to a first dosage of ionizing radiation, thereafter forming the polymer into a finished article and exposing the polymer while in said finished article form to a second dosage of ionizing radiation, the total dosage of ionizing radiation not exceeding about 0.050-2.0 megarads.
Claim 19
Independent Claim
82 words
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer comprising, providing the polymer to be treated in the form of a ground resin or pellet, exposing said polymer while in said ground resin or pellet form to a first dosage of ionizing radiation, thereafter forming the polymer into a finished article and exposing the polymer while in said finished article form to a second dosage of ionizing radiation, the total dosage of ionizing radiation not exceeding about 0.050-2.0 megarads.
Claim 20
Independent Claim
40 words
A method according to claims 11, 13, 1 or 15 wherein the polymer prior to irradiation has an extractable acrylonitrile monomer content of about 1-100 ppm and said monomer content is reduced by at least 50 wt.% by said irradiation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-08-26 | 1989-02-25 | 1989-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-26 | 1993-02-25 | 1993-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-26 | 1997-02-25 | 1997-08-27 | $7700.00 | Window Closed / Lapsed |