2017 Award Nomination

Transcription

1 Title of Innovation: Amercoat One Single-Component Epoxy 2017 Award Nomination Nominee(s): James McCarthy, PPG Protective and Marine Coatings Kamlesh Sheth, PPG Protective and Marine Coatings David Curran, PPG Protective and Marine Coatings Category: Coatings and Linings Dates of Innovation Development: June 2012 to January 2015 Web site: // Summary Description: Until now, single-pack epoxy coatings have been based on epoxy-ester resins, which are not as robust as true amine-cured epoxy coatings, or have been based on epoxy resins and latent hardeners, which require a bake cure and therefore are not practical for most protective and marine coating applications. Amercoat One is a new epoxy coating technology that allows for true epoxy-amine curing in a single-pack product, eliminating certain disadvantages of traditional two-component epoxy technology such as mix-ratio errors, pot life problems, and wasteful packaging, while retaining the performance benefits of a true amine-cured epoxy coating. 1

2 Full Description: (Please provide complete answers to the questions below. Graphs, charts, and photos can be inserted to support the answers.) 1. What is the innovation? Amercoat One is a true amine-cured epoxy coating, supplied in a single container. 2. How does the innovation work? Amercoat One uses patented technology based on epoxy resin and a proprietary blocked amine (ketimine) curing agent. Ketimines are formed by a condensation reaction between ketones and primary amines. In the presence of water, these blocked amines will hydrolyze back to the original amine and ketone. Ketimines are well-known to the epoxy formulating community. They are especially useful for extending pot life of high-solids two-pack epoxy coatings, and in theory, these materials should be able to allow the formulator to produce one-pack aminecured epoxy coatings, provided the mixture is kept free of all traces of moisture. However, up until the present, efforts to produce one-pack epoxy coatings based on current ketimine technology have not been successful. It is very difficult to produce formulated coatings which are completely free of water, and even the slight traces of water adsorbed on pigments or picked up from ambient air contact during processing are enough to cause instability and impractically short shelf life, especially with higher solids (> 60% by volume) coatings. The new technology which is the basis for Amercoat One has resolved the problem of limited stability and inordinately short shelf life. 3. Describe the corrosion problem or technological gap that sparked the development of the innovation? How does the innovation improve upon existing methods/technologies to address this corrosion problem or provide a new solution to bridge the technology gap? Epoxy coatings are a mainstay of the protective and marine coatings markets. Used as intermediate coats over inorganic and organic zinc rich primers, or used as direct-to-metal primers in coating systems, epoxy coatings are widely recognized for their versatility and the excellent corrosion resistance they provide. Epoxy coatings do have some disadvantages however. Since these products dry, or cure, by chemical reaction, the reactive constituents of the finished coating (epoxy resins on the one side, and typically amine or amide-functional materials on the other side) must be packaged separately and then combined in the proper ratio immediately before the application is to commence. Mixing the separate components too far in advance of the coating application can result in unacceptable viscosity increase or even gelling as the reaction proceeds, making the mixed material incapable of being applied. This pot life limitation requires careful planning by the coating applicator. Secondly, although most epoxy coatings are packaged with the correct 2

3 pre-measured mix ratio, oftentimes partial kits are mixed in order to avoid waste when only small amounts of coating are needed, for instance in the case where minor touch-up is needed. Assuring that a correct mix ratio is maintained when partial kits are used can be problematic, especially in field applications where accurate measurement of weights or volumes can be difficult. A third disadvantage is that current packaging for two-component epoxy products is oftentimes wasteful. Because products are sold in kits with the prescribed mix ratio premeasured in each side, the containers used to package each component are often only partially filled in order to allow the contents of the one container to be added to the other. Using partial-filled containers is wasteful of resources and costly. Amercoat One maintains the performance advantages of two-component epoxy coatings while eliminating the disadvantages described above. 4. Has the innovation been tested in the laboratory or in the field? If so, please describe any tests or field demonstrations and the results that support the capability and feasibility of the innovation. Amercoat One is a fully commercialized product and has been successfully used in the field for over one year. Extensive internal laboratory testing has been performed to validate the performance of the product. There are numerous accelerated corrosion tests and specifications that call out corrosion testing (with pass/fail scribe creep criteria) that can be utilized in a lab setting to evaluate corrosion resistance. These include ASTM B117 Salt Fog, ASTM D5894 Cyclic Weathering, and ASTM D2247 Condensing Humidity, among others. Although much debate exists regarding the correlation of these accelerated methods to real-world performance, they are useful in generating comparative data in a lab setting. These tests were used to benchmark the corrosion resistance of the single-pack epoxy technology against two different commercially available two-component epoxy-polyamide controls. The first two-component control is based on 190 EEW liquid epoxy resin and 103 AHEW liquid polyamide resin. The second control is based on 500 EEW solid epoxy resin and 525 AHEW semi-solid polyamide resin. ASTM B117 Salt Fog Test Results For each product under evaluation, three sets, each comprised of triplicate panels, were exposed to salt fog per ASTM B117. At 1000-hour intervals, one set of triplicate panels was removed from the test cabinet and was evaluated for blistering and rusting. After the visual evaluation was completed, the scribe areas were stripped with paint stripper to expose the underlying metal substrate, allowing for accurate scribe creep measurements. Results for the 1000-hour, 2000-hour, and 3000-hour exposure intervals are shown below. All ratings and scribe creep values reported below are the average of the three test panels in each set. 3

4 Table 1 Salt Fog Results Product Avg DFT (mils) Exposure Time (hours) Unscribed Area Blistering Rust (D714) (D610) Scribed Area Blistering (D714) Scribe Creep (mm) Single pack epoxy Epoxy-polyamide A* Epoxy Polyamide B** Single pack epoxy Epoxy-polyamide A* Epoxy Polyamide B** Single pack epoxy Epoxy-polyamide A* Epoxy Polyamide B** *190 EEW epoxy / 103 AHEW polyamide **500 EEW epoxy / 525 AHEW polyamide The results above show that throughout the 3000 hour exposure period, the single-component epoxy coating had similar resistance to blistering and rusting as the two commercially available epoxy-polyamide coatings used as controls. In fact, no blistering or field rusting was observed on any of the test panels. Likewise, when the scribe areas of the test panels were stripped, the single-component epoxy exhibited scribe creep comparable to that of the two-component 4

5 epoxy-polyamide controls, a further indication of comparable performance in this test. Photos of the salt fog exposure panels before and after stripping the scribe area are shown below: Photo hour salt fog panels, after stripping. Photo hour salt fog panels, after stripping. 5

6 Photo hour salt fog panels, after stripping. ASTM D5894 Cyclic Prohesion Test Results As with the salt fog testing, for each product under evaluation, three sets, each comprised of triplicate panels, were exposed to Cyclic Salt Fog/UV Exposure per ASTM D5894. The test cycle consisted of one week in a fluorescent UV/condensation cabinet running a cycle of 4 hours UVA exposure/4 hours condensation, followed by one week exposure in a cyclic Prohesion cabinet with 0.05% sodium chloride and 0.35% ammonium sulfate solution and 1 hour fog /1 hour dry cycle. Total length of time for a complete cycle is 336 hours. In this test, the panel sets were removed at 1500-hour intervals and were evaluated for blistering and rusting in accordance with ASTM D714 Standard Test Method for Evaluating Degree of Blistering of Paints and ASTM D610 Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces. After the visual evaluation was completed, the scribe areas were stripped with paint stripper to expose the underlying metal substrate, allowing for accurate scribe creep measurements. Results for the 1500-hour (roughly 4.5 cycles) and 3000-hour (roughly 9 cycles) exposure intervals are shown below. In this test, only one control was utilized, due to space limitations in the test cabinets. All ratings and scribe creep values reported below are the average of the three test panels in each set. 6

7 Table 2 Prohesion Test Results Product Avg DFT (mils) Exposure Time (hours) Unscribed Area Blistering Rust (D714) (D610) Scribed Area Blistering (D714) Scribe Creep (mm) Single pack epoxy F 0.8 Epoxy Polyamide B** F 0.7 Single pack epoxy F 1.1 Epoxy Polyamide B** F 1.3 *190 EEW epoxy / 103 AHEW polyamide **500 EEW epoxy / 525 AHEW polyamide As with the salt fog testing results, the results above for the cyclic Prohesion testing show that throughout the 3000 hour exposure period, the single-component epoxy coating had similar resistance to blistering and rusting as the commercially available epoxy-polyamide coating used as control. Other than the bottom of the 3000-hour single-component epoxy test panel which had rusting due to edge effects/low film thickness, no blistering or field rusting was observed in the un-scribed area of any of the test panels. The scribes of all test panels did exhibit a few #8 blisters immediately adjacent to the scribe. When the scribe areas of the test panels were stripped, the single-component epoxy exhibited scribe creep comparable to that of the twocomponent epoxy-polyamide control, confirming comparable performance in this test. Photos of the cyclic Prohesion exposure panels before and after stripping the scribe area are shown below: 7

8 Photo hours cyclic Prohesion after stripping Photo hours cyclic Prohesion after stripping 8

9 ASTM D2247 Water Resistance of Coatings in 100% Relative Humidity In this test, the face (un-scribed) of the test panels were placed over a test chamber containing water heated to 100 F. The backs of the panels were exposed to ambient laboratory conditions, thereby creating a temperature gradient causing condensation of the water vapor on the face of the panel. The panels were evaluated for blistering and rusting per ASTM D714 Standard Test Method for Evaluating Degree of Blistering of Paints and ASTM D610 Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces. Results are tabulated below. Since these panels were not scribed, the same panels were evaluated at each exposure interval. Table 3 Condensing Humidity Test Results Product Avg DFT (mils) Exposure Time (hours) Blistering Rust (D714) (D610) Single pack epoxy Epoxy-polyamide A* Epoxy Polyamide B**

10 The above results for the single-component epoxy indicate excellent resistance to condensing humidity, which often induces blistering in less robust coatings. 5. How can the innovation be incorporated into existing corrosion prevention and control activities and how does it benefit the industry/industries it serves (i.e., does it provide a cost and/or time savings; improve an inspection, testing, or data collection process; help to extend the service life of assets or corrosion-control systems, etc.)? Amercoat One can be used on properly prepared ferrous and non-ferrous substrates, as well as concrete. It provides the same high level of corrosion resistance as typical two-component epoxy coatings and can be used anywhere a high level of corrosion protection is needed. Benefits to the industry include: 1. No need to mix multiple components. Because this product is packaged as a single component, mixing errors are eliminated. This is particularly beneficial when field painting is being completed, where mixing of partial kits is done to avoid waste. 2. No pot life limitations. Because this is a single-component product, there is no pot life. The material can be used and reused, as long as the lid is tightly closed. 3. Amercoat One eliminates wasteful packaging typical of two-component products, preserving natural resources and reducing hazardous waste. 6. Is the innovation commercially available? If yes, how long has it been utilized? If not, what is the next step in making the innovation commercially available? What are the challenges, if any, that may affect further development or use of this innovation and how could they be overcome? Amercoat One has been commercially available for approximately 18 months. 7. Are there any patents related to this work? If yes, please provide the patent title, number, and inventor. 10

11 Patent Title: One-Component Epoxy Coating Compositions Patent Number: US B2 Inventors: Norman R. Mowrer, Kamlesh Sheth 11