US4421569A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion protection of steel pipes
Assignee: Sharon Tube Corp
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Filing: 1982-05-07
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Granted: 1983-12-20
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Expires: 2002-05-07
Abstract
Abstract Polymeric coatings are provided on steel pipes to protect the same against corrosion. Monomers and prepolymers are permanently adhered to the surface of steel pipes by graft polymerization to form a barrier which keeps out moisture, oxygen and other corrosive gases from the steel substrate. The monomers and prepolymers are chosen to provide a low moisture vapor transmission rate and oxygen permeability.
Inventors
- 👤 Michael Dichter
- 👤 Carl Horowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:48
CPC Classifications
C; C09; C09D; C09D5/00; C09D5/08; C08; C08F; C08F283/00; C09D4/00; C09D4/06; Y; Y10; Y10S; Y10S138/00; Y10S138/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
116 words
Composition which when cured in contact with a steel object forms a coating thereon to protect the steel object against corrosion, said composition comprising an aqueous emulsion of: (a) hydroxyethyl or hydroxypropyl methacrylate, methyl, ethyl or butyl acrylates or methacrylates, dimethylamino or diethylamino, ethylacrylates or methacrylates, or vinyl pyrrolidone, or mixtures thereof, as monomer, (b) epoxy resins based on bisphenol A and epichlorohydrin, phenol based or cresol based poly functional epoxy novolac resins, water reducible epoxy esters, water reducible urethane prepolymers or hydroxyl terminated or carboxyl terminated acrylic prepolymers, as prepolymer, (c) a silver, ferric ferrous, cupric or cobalt salt or mixtures thereof as graft initiator, (d) a peroxide or persulfate as catalyst, and (e) water.
Claim 2
Dependent Claim
116 words
Composition which when cured in contact with a steel object forms a coating thereon to protect the steel object against corrosion, said composition comprising an aqueous emulsion of: (a) hydroxyethyl or hydroxypropyl methacrylate, methyl, ethyl or butyl acrylates or methacrylates, dimethylamino or diethylamino, ethylacrylates or methacrylates, or vinyl pyrrolidone, or mixtures thereof, as monomer, (b) epoxy resins based on bisphenol A and epichlorohydrin, phenol based or cresol based poly functional epoxy novolac resins, water reducible epoxy esters, water reducible urethane prepolymers or hydroxyl terminated or carboxyl terminated acrylic prepolymers, as prepolymer, (c) a silver, ferric ferrous, cupric or cobalt salt or mixtures thereof as graft initiator, (d) a peroxide or persulfate as catalyst, and (e) water.
Claim 3
Dependent Claim
73 words
Composition according to claim 1 wherein the amount of the monomer is 3-10% of the composition, the amount of the prepolymer is 30-50% of the composition when a prepolymer is an epoxy ester and is 40-65% of the composition when the prepolymer is a hydroxyl or carboxyl terminated acrylic prepolymer, the amount of the graft initiator is 0.01-0.05% by weight of the monomer and the catalyst is 0.5-1.5% by weight of the monomer.
Claim 4
Dependent Claim
79 words
Composition according to claim 1 wherein the amount of monomer is 3-5% of the composition, the amount of the prepolymer is 30-40% by weight of the composition when the prepolymer is an epoxy ester and is 50-60% by weight of the composition when the prepolymer is a hydroxyl or carboxyl terminated acrylic prepolymer, the amount of the graft initiator is 0.02-0.03% by weight of the monomer and the amount of the catalyst is 0.8-1.0% by weight of the monomer.
Claim 5
Dependent Claim
13 words
Composition according to claim 1 wherein the graft initiator is ferrous ammonium sulfate.
Claim 6
Dependent Claim
12 words
Composition according to claim 4 wherein the catalyst is paratoluene sulfonic acid.
Claim 7
Dependent Claim
11 words
Composition according to claim 4 wherein the catalyst is ammonium persulfate.
Claim 8
Dependent Claim
33 words
Method for protecting the surface of a steel object, which comprises applying the composition of claim 1 to the surface of the steel object and curing said composition in contact with said surface.
Claim 9
Dependent Claim
13 words
Method according to claim 7 wherein the steel object is a steel pipe.
Claim 10
Dependent Claim
24 words
Method according to claim 8 wherein the steel pipe is preheated to a temperature of 120°-140° F. prior to application of said composition thereon.
Claim 11
Dependent Claim
19 words
Method according to claim 8 wherein said curing is effected in open air for a period of 5-10 minutes.
References Cited (Backward Citations)
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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) | 1986-12-19 | 1987-06-20 | 1987-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-19 | 1991-06-20 | 1991-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-19 | 1995-06-20 | 1995-12-20 | $7700.00 | Window Closed / Lapsed |