Mineral stains for wood and other substrates

Abstract

According to the invention, a metal salt and an oxygen source are applied to penetrate or impregnate a suitable substrate sequentially in effective amounts so as to react in contact with the substrate and produce a mineral compound fixed within the surface of the substrate. The inventive combination of a mutually compatible metal salt, oxygen source, and substrate brings about an in situ reaction, and modifies the substrate to bring about a lasting desired effect. The mineral compound that is produced according to the invention is linked to the substrate, is stable and long-lasting or permanent, and is immobilized or insolubilized in the substrate. The mineral compound is bound or contained within and on the surface of the substrate, so it may be said to be ingrained in the fibers or matrix of the substrate, or embedded within the substrate. The desired effect is preferably a color. A wide variety of metal salts may be used depending on the desired effect. The oxygen source is preferably a peroxide, and the substrate is preferably a cellulose product such as wood, cotton, or paper; leather; or masonry. The invention contemplates methods of treating substrates, treatment kits, and treated products. With wood products, the invention provides a water-based stain of low toxicity useful for soft woods.

Description

[0001] This application is a division of application Ser. No. 08 / 865,419 filed May 28, 1997.BACKGROUND OF THE INVENTION [0002] This invention relates to a water-based mineral stain for wood and other substrates. More specifically, the invention relates to a process in which a metal salt and an oxygen source react with the substrate to provide a stable color or other desired effect such as preserving the substrate. [0003] Many commercial stains readily available on the market are oil or solvent-based and / or contain hazardous chemicals subject to increasing environmental regulation and health concerns. There is a growing need for water-based colorants and finishes that contain no hazardous chemicals. Federal and state initiatives are leading to bans on stains using volatile organic compounds (e.g. petroleum, mineral spirits, toluene, or benzene). [0004] Most water-based products for coloring and finishing wood and other materials are primarily based upon a pigment or dye suspended in ...

AI Technical Summary

Benefits of technology

[0016] This invention succeeds where previous efforts have failed. It avoids the need for volatile organic solvents and toxic compounds, heat, or pressure—elements employed in the prior art—without loss of ability, and indeed with improved results. It can be applied to a wide variety of woods and other substrates with excellent, permanent results. It works quickly in environments and temperatures inappropriate for conventional treatments, and is simple enough to be used by an amateur.

[0017] This invention solves previously unrecognized problems, including how to react a substrate with a soluble mineral salt and an oxygen source to color the substrate; how to satisfy consumer aesthetics limiting the substitutability of sustainable woods for endangered species; and how to use a single staining system for a wide variety of wood and non-wood substrates. This invention also solves the problem of evenly staining and rapidly aging soft woods and green woods and related materials, which was generally thought to be insoluble. The advantages provided by the invention could not previously have been appreciated, such as its adaptability to a variety of overcoat finishes, the ability to stain without appreciably raising wood grain, and its retention of the aromatic quality of the substrate.

[0019] The inventive approach to the coloring and preserving of cellulose and other materials is a process whereby a water-soluble mineral salt is saturated into the substrate material and subsequently oxidized and somehow linked or bonded to that material. This process has no precedent in the marketplace and provides important advantages in both the commercial and consumer markets. In a preferred embodiment, the inventive stains are completely water-based. The process does not require a binder of any kind, petroleum products, organic solvents, acrylic resins, dyes, or other expensive or toxic materials. The component materials have low-impact on both the environment and human heath. The unique characteristics of the product, its permanence even in exterior applications, its ability to evenly stain extremely soft woods and penetrate extremely hard woods, its simulated aging of wood, and the richness of the colors achieved will appeal even to those completely unconcerned about its environmental and health advantages.

[0024] In a preferred embodiment, the substrate is a sustainably harvested wood, the stain is relatively uniform, the metal salt is of low toxicity and not considered hazardous, the preparations of metal salt and oxygen source are water-based solutions, and the oxygen source leaves essentially no residue. Preferably, the metal salt preparation and the oxygen source preparation are aqueous solutions.

Problems solved by technology

Such products, although less toxic, exacerbate a problem of all conventional stains, namely that while coloring a wood such as pine they sink in more deeply into the soft pulp and are repelled by the harder wood around the annual growth rings formed during the dormant period in a tree's growing season.

Also, water-based stains tend to raise wood grain, requiring additional sanding.

Many of these coloring agents are “fugitive,” fading over time, especially in exterior settings.

Oil-based conventional stains can be difficult to over-coat with water-based acrylic finishes.

Stains used to simulate wood aging, such as Cabot Stains Bleaching Oil™ can only be used for exterior use and the appearance of aging of the wood takes many months from application.

Other aging processes require the use of harsh acids, bleaches and other toxic chemicals and require complex manual wood-distressing techniques such as multiple layering of different stains to mimic grain patterns of aged wood.

This method requires immersing wood at high temperature and pressure and sanding to remove an unattractive deposit, so it is not a viable method for staining wood.

The coloring is unstable, uneven, fades over time, leaches out if exposed to moisture, and if overcoated creates an unattractive residue, so it is not in regular use.