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

"This patent describes a method for coloring and preserving substrates using a metal salt and an oxygen source. The process involves applying the metal salt and oxygen source separately, allowing them to penetrate the substrate and react in contact with it to produce a stable, water-insoluble stain. The resulting stain is permanent, even in exterior applications, and can be used on a wide variety of substrates. The method is water-based, non-toxic, and does not require any expensive or toxic materials. The resulting stain is rich in color and has low-impact on the environment and human health. The method can be used on sustainably harvested wood, and the stain is relatively uniform. The metal salt can be any appropriate mineral salt, such as iron, silver, zinc, cerium, copper, magnesium, molybdenum, nickel, tin, chromium, aluminum, and titanium."

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.