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EP-3429980-B1 - SURFACE APPLIED CORROSION INHIBITOR

EP3429980B1EP 3429980 B1EP3429980 B1EP 3429980B1EP-3429980-B1

Inventors

  • GOODWIN, FREDERICK R
  • CROMWELL, Olivia R

Dates

Publication Date
20260513
Application Date
20170313

Claims (20)

  1. A sealer composition for a cementitious substrate, comprising a non-aqueous blend of: a first silane; a second silane having a higher molecular weight than said first silane; and at least one corrosion inhibitor, wherein said corrosion inhibitor is soluble in silane, soluble in solvent-diluted silane, and at least partially soluble in water, wherein the silanes are independently selected from the group consisting of alkyl trialkoxysilanes, dialkyl dialkoxysilanes and trialkyl alkoxysilanes, wherein the molecular weight of said first silane is from 104 g/mol to 270 g/mol, and wherein the molecular weight of said second silane is from 270 g/mol to 576 g/mol, and wherein said corrosion inhibitor is selected from the group consisting of alkyl acetamides, alkyl carboxylic acids and salts thereof, alkoxy carboxylic acids and salts thereof, alkoxylates, phosphorus containing compounds, triazines, and mixtures thereof.
  2. The sealer composition of claim 1, wherein the molecular weight of said first silane is from 150 g/mol to 250 g/mol, and wherein the molecular weight of said second silane is from 270 g/mol to 400 g/mol.
  3. The sealer composition of claim 1, wherein the molecular weight of said first silane is from 170 g/mol to 240 g/mol, and wherein the molecular weight of said second silane is from 270 g/mol to 300 g/mol.
  4. The sealer composition of claim 1, wherein said first silane is selected from the group consisting of methyl trimethoxysilane, ethyl trimethoxysilane, n-butyl trimethoxysilane, isobutyl trimethoxysilane, methyl triethoxysilane, ethyl triethoxysilane, n-butyl triethoxysilane, and isobutyl triethoxysilane.
  5. The sealer composition of claim 4, wherein said first silane is selected from the group consisting of methyl triethoxysilane and isobutyl triethoxysilane.
  6. The sealer composition of claim 5, wherein said second silane is selected from the group consisting of n-octyl trimethoxysilane, isooctyl trimethoxysilane, dodecyl trimethoxysilane, hexadecyl trimethoxysilane, n-octyl triethoxysilane, isooctyl triethoxysilane, dodecyl triethoxysilane, and hexadecyl triethoxysilane.
  7. The sealer composition of claim 6, wherein said second silane comprises n-octyl triethoxysilane.
  8. The sealer composition of claim 1, wherein said first silane comprises isobutyl triethoxysilane, and wherein said second silane comprises n-octyl triethoxysilane.
  9. The sealer composition of claim 1, wherein said cementitious substrate is selected from the group consisting of concrete, masonry, and mortar.
  10. The sealer composition of claim 9, wherein said cementitious substrate comprises concrete.
  11. The sealer composition of claim 1, wherein said corrosion inhibitor is selected from the group consisting of dimethyl acetamide, diethyl acetamide, disodium sebacate, iso-nonyl phenoxy acetic acid, ethynylcarbinolalkoxylate, octane phosphonic acid, mono-n-octyl phosphate ester, amine blocked C 6 -C 10 alkyl phosphate monoester, triisobutyl phosphate, polyether phosphate, 1,3,5-Tris[3-(dimethylamino)propyl]hexahydro-1,3,5-triazine, and mixtures thereof.
  12. The sealer composition of claim 11, wherein said corrosion inhibitor comprises a blend of ethynylcarbinolalkoxylate and amine blocked C 6 -C 10 alkyl phosphate monoester.
  13. The sealer composition of claim 11, wherein said corrosion inhibitor comprises a blend of dimethyl acetamide and triisobutyl phosphate.
  14. The sealer composition of claim 11, wherein said corrosion inhibitor comprises a blend of dimethyl acetamide and triisobutyl phosphate.
  15. A cementitious structure comprising: a cementitious substrate; and a sealer composition according to any one of claims 1 to 14, said sealer applied to the surface of said cementitious substrate and at least partially penetrating into said substrate.
  16. The cementitious structure of claim 15, wherein said cementitious substrate is selected from the group consisting of concrete, masonry, and mortar substrates.
  17. The cementitious structure of claim 16, wherein said cementitious substrate is selected from the group consisting of concrete and masonry substrates.
  18. The cementitious structure of claim 17, wherein said cementitious substrate comprises a concrete substrate.
  19. A method of sealing a steel reinforced cementitious structure comprising a cementitious substrate from intrusion of corrosion-causing agents, comprising: applying to a surface of said substrate to be sealed a sealer composition according to any one of claims 1 to 14 and permitting the sealer composition to penetrate into the substrate.
  20. The method of sealing a steel reinforced cementitious structure of claim 19, wherein said cementitious substrate is selected from the group consisting of concrete, masonry, and mortar substrates.

Description

BACKGROUND Corrosion is a naturally occurring phenomenon commonly defined as the deterioration of a substance (usually a metal) or its properties as a result of a reaction with its environment. Like other natural hazards such as earthquakes or severe weather disturbances, corrosion can cause dangerous and expensive damage to wastewater systems, pipelines, bridges, roadways and public buildings. Corrosion is a tremendous problem and cost to society. In 2001, as part of the Transportation Equity Act for the 21st Century, the United States Congress mandated a comprehensive study to provide cost estimates and national strategies to minimize the impact of corrosion. The study was conducted by CC Technologies Laboratories, Inc. of Dublin, Ohio with support from NACE International - The Corrosion Society and the United States Federal Highway Administration (FHWA). This study titled "Corrosion Cost And Preventive Strategies In The United States" is a comprehensive reference on the economic impact of corrosion, estimated at the time to be a staggering annual cost of $276 billion. According to the study, reported to the Office Of Infrastructure Research and Development, corrosion and metal wastage arising from oxidation as caused by exposure to the elements and reactivity between dissimilar materials costs many segments of the United States economy billions of dollars every year. The study covered a large number of economic sectors, including the transportation infrastructure, electric power industry, conveyance and storage. It has now been estimated that the annual cost of corrosion in the United States has grown to $400 billion. NACE International also published a study titled "International Measures of Prevention, Application and Economics of Corrosion Technologies Study" on March 1, 2016. The NACE study examined the global impact of corrosion, the role of corrosion management in industry and government and, attempts to establish best practices for corrosion management through the life cycle of assets. At the time of the study, the indirect cost of corrosion was conservatively estimated to be equal to the direct cost, giving a total direct plus indirect cost of more than $600 billion or 6 percent of GDP. It has now been estimated that the annual total direct plus indirect cost is more than $800 billion. This cost is considered to be a conservative estimate since only well-documented costs were used in the study. In addition to causing severe damage and threats to public safety, corrosion disrupts operations and requires extensive repair and replacement of failed assets. The U.S. Federal Highway Administration has rated almost 200,000 bridges, or one of every three bridges in the U.S., as structurally deficient or functionally obsolete. Furthermore, more than one-fourth of all bridges are over 50 years old, the average design-life of a bridge. The road and bridge infrastructure in the United States is crumbling, with thousands of bridges rated as unsafe and in need of replacement or major repairs. In many of these cases, corrosion plays a significant role in undermining safety. Corrosion protection measures could help minimize or avoid further problems. Steps are being taken to address America's aging infrastructure. For example, House bill H.R. 1682, the "Bridge Life Extension Act 2009," introduced in March 2009, would require States to submit a plan for the prevention and mitigation of damage caused by corrosion when seeking federal funds to build a new bridge or rehabilitate an existing bridge. Many reinforced concrete structures suffer from premature degradation. Concrete embedded steel reinforcement is initially protected from corrosion by the development of a stable oxide film on its surface. This film, or passivation layer, is formed by a chemical reaction between the highly alkaline concrete pore water and the steel. The passivity provided by the alkaline conditions may be destroyed by the presence of chloride. The chloride ions locally de-passivate the metal and promote active metal dissolution. Corrosion of the steel is usually negligible until the chloride ions reach a concentration where corrosion initiates. The threshold concentration depends on a number of factors including, for example, the steel microenvironment, the pore solution pH, the interference from other ions in the pore solution, the electrical potential of the reinforcing steel, the oxygen concentration and ionic mobility. The chloride acts as a catalyst in that it does not get consumed in the corrosion reaction, but remains active to again participate in the corrosion reaction. The presence of chloride does not have a directly adverse effect on the concrete itself, but does promote corrosion of the steel reinforcement. The corrosion products that form on the steel reinforcement occupy more space than the steel reinforcement causing pressure to be exerted on the concrete from within. This internal pressure builds over time and eventually l