Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Utility Patent
1998-11-17
2001-01-02
Fries, Kery (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C510S122000, C510S179000, C510S180000, C510S219000, C510S241000, C510S243000, C510S400000
Utility Patent
active
06169066
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a hydrophobic protective coating composition and, more particularly, to a hydrophobic protective coating composition that is waterborne and that is formulated to simultaneously clean the applied-to substrate surface and provide a hydrophobic thin-film coating thereon.
BACKGROUND OF THE INVENTION
Coating compositions that are formulated for application onto substrates such as optical surfaces, e.g., vehicle windshields or windows, windows on marine vessels and the like, to provide a hydrophobic surface thereon are known in the art. These coatings are desired because they promote water shedding from the optical surface without the need for mechanical wiping, or with reduced mechanical assistance.
Typically, such hydrophobic coating compositions known in the art are formed from materials that, once applied to the substrate surface, only temporarily reside thereon and do not form a bond thereto. The failure of such coating products to form a bond with the underlying surface ultimately reduces the length of time that the coating remains on the substrate surface, thereby limiting the effective duration during which the product can provide a desired hydrophobic effect.
Additionally, hydrophobic coatings known in the art are typically applied as a final step of a multi-step system, requiring either a previous cleaning step or previous cleaning and surface preparation steps. For example, in a three-step process, the desired substrate surface is first cleaned to remove any surface dirt or debris, and the cleaned surface is then prepared to accept the hydrophobic coating by subsequently applying a suitable preparation agent thereto: In some instances, depending on the particular hydrophobic coating system, it may be required that the surface preparation agent be allowed to set for a period of time and/or be exposed to certain activating or curing temperatures before applying the hydrophobic coating and/or be exposed to certain curing temperatures. In certain instances it may also be required that the applied hydrophobic coating composition be cured at a certain temperature for a certain period of time to provide the desired hydrophobic surface. Accordingly, the task of achieving a hydrophobic surface coating using such known compositions can involve a time and labor intensive process.
It is, therefore, desirable that a coating composition be formulated that will enable application to an optical or other substrate surface to produce a hydrophobic coating without the need to clean and prepare the substrate surface using separate products or steps. It is desired that such coating composition be formulated to provide a hydrophobic surface coating having a long service life. It is also desired that such coating composition be fast and easy to use without the need for special skills or tools.
SUMMARY OF THE INVENTION
Waterborne hydrophobic cleaning and coating compositions of this invention are prepared by combining one or more silicone ingredients, with water, and at least one solubilizing agent capable of making the silicone ingredient miscible in water to form a homogeneous mixture. Optionally, cleaning and coating compositions of this invention can include volatilizing agents, to reduce application time, and colorizing agents, to provide a desired composition color. The silicone ingredient can be selected from the group of silicone resins, silicone fluids, and mixtures thereof. Preferably, the silicone ingredient comprises a functional group that is capable of forming a bond with a chemical group of the underlying substrate. Preferably, the solubilizing agent is one that is selected from the group consisting of organic solvents, alcohols, ketones, acetates, ethers, esters, aromatics and mixtures thereof that are soluble in water and that are capable of cleaning a substrate surface.
Coating compositions of this invention are capable of simultaneously cleaning, preparing a substrate surface, and providing a protective thin-film hydrophobic surface thereon at ambient temperature without conducting a multi-step process and without having to use special equipment. Coating compositions of this invention, when applied to an optical glass surface, form a bond therewith that improves the duration of such protective surface.
DETAILED DESCRIPTION OF THE INVENTION
Hydrophobic coating compositions of this invention are prepared by combining one or more silicone ingredients, with water, one or more solubilizing agents or solvents, an optional volatilizing agent, and an optional coloring agent. Coating compositions of this invention simultaneously clean the substrate surface and provide a hydrophobic coating thereon in a single step at ambient temperature without special application techniques or equipment. Coating compositions of this invention are believed to form a bond with the underlying substrate, in the case of the substrate being glass, to provide a hydrophobic coating thereon that has an improved service life when compared to conventional hydrophobic coating products.
The silicone ingredient is used to provide a thin film low energy coating that provides hydrophobicity to the applied-to substrate surface. The silicone ingredient can be selected from the group of silicone intermediates, silicone resins, silicone fluids, and mixtures thereof. In an example embodiment, a silicone resin and a silicone fluid is used because the silicone resin is responsible for forming a low surface energy coating to the substrate while the silicone fluid assists in lubricity during application and also imparts an immediate hydrophobicity to the glass, protecting the silicone resin from self condensation during its curing process. If the silicone resin is used without the silicone fluid, improper curing of the coated composition could result by initial contact with environmental moisture or water, thereby reducing the longevity of the coating hydrophobicity performance. This is known to occur due to the alkoxy groups being reactive with such moisture to provide hydroxy functionality that could promote self condensation.
Silicone resins useful for preparing hydrophobic coating compositions of this invention include alkoxy and hydroxy-functional polysiloxanes. Preferred silicone resins are limited to polyalkylene oxide modified polysiloxanes having a weight average molecular weight in the range of from about 600 to 3,500, and having an ethylene oxide content greater than about 75 percent. A particularly preferred silicone resin is polyalkylene oxide modified polysiloxane available from, for example, OSI Specialties, Inc., of Tarrytown, N.Y. under the product name Silwet 7000 series.
It is desired that in the range of from about 2 to 15 percent by weight of the silicone resin be used based on the weight of the total coating composition. Using less than about 2 percent by weight of the silicone resin can produce a coating composition that does not have a desired degree of hydrophobicity for a particular application. Using greater than about 15 percent by weight of the silicone resin can produce a coating composition that is difficult to apply, and that provides an oily film after application that can adversely affect optical clarity. In a preferred embodiment, approximately 5 percent by weight of the silicone resin is used to prepare the coating composition.
Silicone fluid is used to in combination with the silicone resin to also provide desired hydrophobic properties to the applied coating. Specifically, the silicone fluid is used to reduce the solubility of the silicone resin, thereby improving its solubility with water and making it easier to apply to a desired substrate. Hydrophobic coating compositions of this invention can be prepared using one or a combination of silicone fluids, e.g., by using two or more different types of silicone fluids, or by using similar types of silicone fluids having different viscosities.
Silicone fluids useful in preparing hydrophobic coating compositions of this invention include those having alkyl or polyalkyl groups, and having a visc
Ameron International Corporation
Christie Parker & Hale LLP
Fries Kery
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