Compositions: coating or plastic – Coating or plastic compositions – Coating repellent
Patent
1993-11-29
1995-04-25
Bell, Mark L.
Compositions: coating or plastic
Coating or plastic compositions
Coating repellent
10628719, 10628725, 106271, 427391, 427395, 427394, 427396, 427397, C09K 318
Patent
active
054095271
DESCRIPTION:
BRIEF SUMMARY
This invention relates to aqueous, air drying, water repellent compositions that provide improved long-term water repellency to substrates such as wood and other cellulosic materials, textiles, masonry and concrete. The compositions are also useful in imparting hydrophobicity to powders, for example calcium carbonate, as well as printing inks, adhesives, leather and water-based surface coatings.
Many organic solvent-based coating compositions have been developed which show good water repellency but the use of organic solvents is now a cause for concern on environmental and health grounds. A water repellent system dispersible in water, thus reducing the volatile organic content to a minimum without affecting water repellency properties, is highly desirable.
Aqueous water repellent systems, ie. systems which are dispersible in water, have been developed previously. GB2168394 describes water dispersible compositions useful for preparing aqueous water repellent systems comprising a saturated hydrocarbon wax, at least one oil-soluble metal salt of an organic carboxylic acid, at least one sufactant and at least one hydrocarbon solvent.
The compositions can be mixed or diluted with water to form the desired aqueous water repellent systems.
According to the present invention there is provided an aqueous water repellent composition comprising the reaction product of (i) one or more carboxylic acids or anhydrides containing from 3 to 22 carbon atoms, (ii) one or more polyfunctional aromatic or aliphatic amines or substituted amines containing from 2 to 25 carbon atoms, and (iii) a water soluble metal complex crosslinking agent containing one or more metals selected from zinc, aluminium, titanium, copper, chromium, iron, zirconium and lead.
In particular embodiments of the invention the presence of aqueous acrylic polymers contributes to the stability of the complex compositions as well as giving improved water repellency by additional crosslinking, and possibly a degree of film formation when larger amounts are used.
In a preferred embodiment of the invention, a saturated hydrocarbon wax and/or alkyd resin may be incorporated into the water repellent systems to improve water repellent properties.
In further embodiments of the invention, small amounts of solubilising agents such as sodium hydroxide or ammonia may be added to improve stability.
The compositions broadly described above are useful in that they can be mixed with water to form water repellent systems stable for long periods when mixed, and find application in imparting water repellency to many materials including, wood, paper, and other cellulosic materials, textiles, masonry, cement, surface coatings, powders, inks, leather and adhesives.
In a typical treatment for imparting water repellency to a wood substrate, it is believed that on contact with the wood a reaction takes place which enables the carboxylic acid and/or amine compound to crosslink with the reactive metal of the metal organic compound to form a water repellent substrate under ambient conditions. Wax, if present as a constituent, adds to the substantivity of the repellency.
A particular advantage of the water repellent systems of the present invention is that the use of undesirable hydrocarbon or other organic solvents is unnecessary to maintain the water repellents in solution. The water repellents of the invention are dispersed in a wholly aqueous medium for use in the treatment of the various substrates. The weight of solids in the solution is preferably in the range from 1% to 10%.
In preferred aspects of the invention, the carboxylic acid used is a saturated or unsaturated fatty acid exemplified by oleic, isostearic, stearic and ricinoleic acids. Thus an amine soap of isostearic acid was prepared by adding molten isostearic acid at 70.degree.-80.degree. C. to an agitated solution of triethanolamine in water. The mixture was agitated for 15 minutes, allowed to cool below 50.degree. C. and a zirconiummetal crosslinking agent was added to form an example of a water repellent composition a
REFERENCES:
patent: 2737458 (1956-03-01), Burnham
patent: 3374100 (1968-03-01), Goldstein et al.
patent: 3660303 (1972-05-01), Hiestand
patent: 3901727 (1975-08-01), Loudas
patent: 3912674 (1975-10-01), Stahl
patent: 4360385 (1982-11-01), Grunewalder
Baker Gary
Prince John W.
Bell Mark L.
Bonnir C. M.
Manchem Limited
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