Patent US4294748A successfully refreshed from Google Patents.
US4294748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low viscosity unsaturated polyester resins
Assignee: SNIA Viscosa SpA
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Filing: 1979-12-27
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Granted: 1981-10-13
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Expires: 1999-12-27
Abstract
Abstract A low viscosity unsaturated polyester resin for making products, optionally reinforced with glass fibers is described, which comprises an alkyd prepared by esterification of maleic anhydride and/or acid and/or fumaric acid in association with isophtalic acid, with one or more glycols, essentially comprising dipropylene glycol, and further comprises 25-40% by weight of the total resin of an ethylenically unsaturated monomer copolymerizable with the alkyd essentially chosen among styrene and vinyl toluene, the alkyd having a molecular weight/double bond factor between 300 and 390 and an amount of free functional groups between 50 and 85 mg of KOH per g of alkyd inclusive. The products obtainable from said resin are also described. The resin behaves better in processing has lower heat development and shrinkage than the comparable prior art resins while the mechanical properties of the finished products are very good.
Inventors
- 👤 Giovanni Corrado
- 👤 Elvio Bertotti
- 👤 Bruno Sopino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:18
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/66; C08G63/668; C08G63/676; C08K; C08K3/00; C08K3/40
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
140 words
Low viscosity unsaturated polyester resins for making products, optionally reinforced with glass fibers, by conventional polyester resin processing techniques, essentially comprising: (A) an alkyd prepared by esterification of (a) a compound selected from the group consisting of maleic anhydride, maleic acid, fumaric acid, and mixtures thereof in association with isophthalic acid, with (b) one or more glycols, essentially comprising dipropylene glycol, and at least (B) one monomer copolymerizable with (A), selected from the group consisting of styrene, toluene, and mixtures thereof, in an amount of 25-40% by weight of the total (A)+(B), said unsaturated polyester resins being characterized in that said alkyd A has a molecular weight/double bond factor between 300 and 390 and an amount of free functional groups constituted by hydroxyl groups+carboxyl groups, of between 50 and 85, inclusive expressed as mg of KOH per g of alkyd.
Claim 2
Dependent Claim
140 words
Low viscosity unsaturated polyester resins for making products, optionally reinforced with glass fibers, by conventional polyester resin processing techniques, essentially comprising: (A) an alkyd prepared by esterification of (a) a compound selected from the group consisting of maleic anhydride, maleic acid, fumaric acid, and mixtures thereof in association with isophthalic acid, with (b) one or more glycols, essentially comprising dipropylene glycol, and at least (B) one monomer copolymerizable with (A), selected from the group consisting of styrene, toluene, and mixtures thereof, in an amount of 25-40% by weight of the total (A)+(B), said unsaturated polyester resins being characterized in that said alkyd A has a molecular weight/double bond factor between 300 and 390 and an amount of free functional groups constituted by hydroxyl groups+carboxyl groups, of between 50 and 85, inclusive expressed as mg of KOH per g of alkyd.
Claim 3
Dependent Claim
70 words
Polyester resins according to claim 1, wherein styrene is employed as said copolymerizable monomer, characterized by the fact that said resins have the following viscosity values, expressed as cps at 25° C., as a function of the content of styrene in the total alkyd+styrene: ______________________________________
% by weight of styrene
on the total Viscosity ± 10% at 25° C.
______________________________________
25 1800 cps
35 350 cps
40 150 cps
______________________________________
Claim 4
Dependent Claim
40 words
Unsaturated polyester resins according to either claim 1 or 2, characterized by the fact that as component (a) fumaric acid mixed with isophtalic acid is employed; as component (b) 1,2-dipropylene glycol is employed and as component (B) styrene is employed.
Claim 5
Dependent Claim
64 words
The polyester resins according to either of claims 1 or 2, wherein said resins are processed into final products by a process selected from injection between coupled moulds, impregnation by manual stratification, impregnation by simultaneous cutting and spraying, moulding in a press at low pressures, vacuum moulding, filament winding, hot moulding with coupled metal moulds, or casting with open moulds and without glass reinforcement.
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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) | 1984-10-12 | 1985-04-13 | 1985-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-12 | 1989-04-13 | 1989-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-12 | 1993-04-13 | 1993-10-13 | $7700.00 | Window Closed / Lapsed |