US4292419A
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Process for producing radiation-shielding plastic materials
Assignee: Mitsubishi Chemical Corp
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Filing: 1980-04-24
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Granted: 1981-09-29
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Expires: 2000-04-24
Abstract
Abstract A radiation-shielding plastic material having an excellent transparency and superior mechanical properties, is produced by polymerizing, in the presence of a lead compound, a mixture of a vinyl monomer component (A) consisting of at least one member selected from alkyl methacrylates and acrylates, hydroxyalkyl methacrylates and acrylates and styrene and an organic acid component (B) containing, as an indispensable ingredient, at least one member selected from the compounds of the formulae (I) through (IV): <IMAGE> (I) <IMAGE> (II) <IMAGE> (III) <IMAGE> (IV) wherein R1=C1-10 hydrocarbon radical, R2=C1-7 hydrocarbon radical, R3 and R4=H or CH3, R5=C2-7 hydrocarbon radical, R6=C1-3 hydrocarbon radical and n=0 DIFFERENCE 4.
Inventors
- 👤 Kazumasa Kamada
- 👤 Kazuya Okada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:46
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/44; G; G21; G21F; G21F1/00; G21F1/02; G21F1/10; G21F1/103; G21F1/106
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
227 words
A process for producing a radiation-shielding plastic material, which comprises polymerizing, in the presence of a radical polymerization initiator and a lead compound, a mixture of: (A) 10 to 94% by weight of a vinyl monomer component consisting of at least one vinyl monomer selected from the group consisting of alkyl methacrylates, alkyl acrylates, hydroxyalkyl methacrylates and hydroxyalkyl acrylates, in each of which the alkyl radical has 1 to 4 carbon atoms, and styrene, and; (B) 6 to 90% by weight of an organic acid component containing, as an indispensable ingredient, at least one carboxylic acid selected from the group consisting of: (a) dibasic carboxylic acid monoesters of the formula (I): ##STR7## (b) unsaturated carboxylic acid of the formula (II): ##STR8## (c) oxocarboxylic acids of the formula (III): ##STR9## (d) hydroxycarboxylic acids of the formula (IV): ##STR10## in which formulae (I) through (IV), R 1 represents a hydrocarbon radical having 1 to 10 carbon atoms; R 2 represents a hydrocarbon radical having 1 to 7 carbon atoms; R 3 and R 4 respectively represent, independently from each other, a member selected from the group consisting of a hydrogen atom and a methyl radical; R 5 represents a hydrocarbon radical having 2 to 7 carbon atoms; R 6 represents a hydrocarbon radical having 1 to 3 carbon atoms, and; n represents an integer of from 0 to 4.
Claim 2
Dependent Claim
227 words
A process for producing a radiation-shielding plastic material, which comprises polymerizing, in the presence of a radical polymerization initiator and a lead compound, a mixture of: (A) 10 to 94% by weight of a vinyl monomer component consisting of at least one vinyl monomer selected from the group consisting of alkyl methacrylates, alkyl acrylates, hydroxyalkyl methacrylates and hydroxyalkyl acrylates, in each of which the alkyl radical has 1 to 4 carbon atoms, and styrene, and; (B) 6 to 90% by weight of an organic acid component containing, as an indispensable ingredient, at least one carboxylic acid selected from the group consisting of: (a) dibasic carboxylic acid monoesters of the formula (I): ##STR7## (b) unsaturated carboxylic acid of the formula (II): ##STR8## (c) oxocarboxylic acids of the formula (III): ##STR9## (d) hydroxycarboxylic acids of the formula (IV): ##STR10## in which formulae (I) through (IV), R 1 represents a hydrocarbon radical having 1 to 10 carbon atoms; R 2 represents a hydrocarbon radical having 1 to 7 carbon atoms; R 3 and R 4 respectively represent, independently from each other, a member selected from the group consisting of a hydrogen atom and a methyl radical; R 5 represents a hydrocarbon radical having 2 to 7 carbon atoms; R 6 represents a hydrocarbon radical having 1 to 3 carbon atoms, and; n represents an integer of from 0 to 4.
Claim 3
Dependent Claim
42 words
A process as claimed in claim 1, wherein the molar amount of said lead compound in terms of lead, corresponds to 50% or less of the sum of the molar amounts of said organic acids contained in said organic acid component (B).
Claim 4
Dependent Claim
39 words
A process as claimed in claim 1, wherein the sum of the amounts of said organic acids contained in said organic acid component (B) is not less than 5% of the entire weight of said organic acid component (B).
Claim 5
Dependent Claim
45 words
A process as claimed in claim 1, wherein said dibasic carboxylic acid ester of the formula (I) is a monoester of a dibasic carboxylic acid, which has a hydrocarbon radical having 2 to 3 carbon atoms, with an alcohol having 1 to 10 carbon atoms.
Claim 6
Dependent Claim
53 words
A process as claimed in claim 1, wherein said unsaturated carboxylic acid of the formula (II) is a monoester of a dibasic carboxylic acid, which has a hydrocarbon radical having 2 to 3 carbon atoms, with a member selected from the group consisting of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate.
Claim 7
Dependent Claim
31 words
A process as claimed in claim 1, wherein said oxocarboxylic acid of the formula (III) is selected from the group consisting of pyruvic acid, levulinic acid, acetylbutyric acid and acetylvaleric acid.
Claim 8
Dependent Claim
27 words
A process as claimed in claim 1, wherein said hydroxycarboxylic acid of the formula (IV) is selected from the group consisting of lactic acid and glycollic acid.
Claim 9
Dependent Claim
47 words
A process as claimed in claim 1, wherein said organic acid component (B) contains, as a dispensable ingredient, at least one member selected from the group consisting of polymerizable unsaturated carboxylic acids and nonpolymerizable carboxylic acids, which has a hydrocarbon radical having 4 to 10 carbon atoms.
Claim 10
Dependent Claim
29 words
A process as claimed in claim 1, wherein said lead compound is selected from the group consisting of lead monoxide, lead acetate, lead propionate, lead isobutyrate and lead lactate.
Claim 11
Dependent Claim
28 words
A process as claimed in claim 1, wherein the content of lead in the resultant plastic material is in a range of from 5 to 54% by weight.
Claim 12
Dependent Claim
16 words
A process as claimed in claim 1, wherein said polymerization is carried out in a mold.
Claim 13
Dependent Claim
16 words
A process as claimed in claim 11, wherein said mold is composed of a tempered glass.
Claim 14
Dependent Claim
16 words
A process as claimed in claim 11, wherein said mold is composed of a stainless steel.
Claim 15
Dependent Claim
22 words
A process as claimed in claim 11, wherein said mold is composed of an acrylic resin sheet superimposed on a glass plate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-28 | 1985-03-30 | 1985-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-28 | 1989-03-30 | 1989-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-28 | 1993-03-30 | 1993-09-29 | $7700.00 | Window Closed / Lapsed |