Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From sulfur-containing reactant
Reexamination Certificate
2000-04-17
2001-10-16
Chen, Vivian (Department: 1773)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From sulfur-containing reactant
C528S373000, C528S389000, C106S015050, C106S018340, C106S287260, C106S287320
Reexamination Certificate
active
06303746
ABSTRACT:
BACKGROUND OF THE INVENTION
The use of tropical hardwood, which needs no or very little artificial preservation, in agricultural, hydrological and building applications throughout the world is expected to be prohibited because the availability of hardwoods from non-durable resources, namely, from demolishing wild forest, will be severely curtailed. The problem, therefore, for the future is to develop environmentally compatible preservatives for softwoods from northern regions like Canada, Scandinavia and Siberia so that they can compete with hardwoods in commercial applications. In the United States alone, the wood preserving industry used over one hundred and seventy million pounds of preservative chemicals to pressure treat four hundred and eighty-four million cubic feet of wood in 1990. The future of the three most widely used preservatives, namely, chromated copper arsenate (CCA), pentachloro phenol (PCP) and creosote (which is a mixture of phenolic compounds) is very bleak because of their toxicity and propensity to leaching from incorporated wood. These compounds, therefore, are receiving regulatory pressure from the government environmental protection agencies and face elimination as soon as viable alternatives are found.
In addition to phenolic compounds, sulfur compounds are extensively used in agricultural field as herbicides and insecticides. Therefore, it is an objective of this invention to prepare wood preservative compounds containing both phenol and sulfur moieties in the compounds. These compounds should be in oligomeric or polymeric form so that they would have a reduced tendency to leach out from incorporated woods. Examples of the use of monomeric phenol/sulfur compounds as antioxidants in the plastics and food applications can be found in the literature. Derwent Patent Abstract 86-292906/45 (1986) describes the use of mercaptophenols (obtained by reducing polythiobisphenols) as antioxidants for rubbers and plastics; Derwent Patent Abstract 90-62763/09 (1990) describes an antibacterial composition for paints and wooden articles comprising bithionol or fenticlor and trihalogenated phenol; Derwent Patent Abstract 90-87253/12 (1990) describes a delayed release antibacterial composition comprising an inclusion compound of hinokitiol with a bisphenol; and Derwent Patent Abstract 91-248660/34 (1990) describes a bactericidal and fungicidal composition prepared from a mixture of chlorhexidine trihalogenated phenols and phenylphenols. In addition, K. Asakura et al., Journal of the American Oil Chemists' Society, Vol. 66, No. 10, October, 1989, pp. 1450-1453 report the antioxidant effect and antimicrobial activity of phenolic sulfides wherein the sulfur is attached to the alkyl side chain. These phenolic sulfides were prepared by Michael addition and radical addition reactions of ethanethiol and ethanedithiol with o-, m- and p-vinylphenol. U.S. Pat. No. 3,812,192 to R. Gabler et al. reports that certain bisphenol compounds linked together with a thio bridge are highly active fungicides having a broad spectrum of activity.
A recent disclosure that oligomeric phenol sulfide compositions exhibit antimicrobial activity is found in K. Kawada et al., J. Antibact. Antifung. Agents, Vol. 13, No. 5, pp. 205-209 where it was reported that the tested monosulfide dimers and monosulfide oligomers were found to be less active against certain bacteria and fungi than the startingf alkylphenols.
SUMMARY OF THE INVENTION
The present invention, in one embodiment, relates to an article comprising wood and an effective amount for the preservation of the wood of a polymeric phenol sulfide, which can be a polymeric alkyl phenol sulfide, such as one containing an alkyl group containing from one to about four carbon atoms in the alkyl group contained therein. The invention also relates to a method of preserving an article which comprises wood which comprises applying to the article an effective amount for preservation of the wood of a polymeric phenol sulfide, such as one containing an alkyl group containing from one to about four carbon atoms in the alkyl group contained therein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The polymeric phenol sulfides, optionally where the phenol group therein is substituted with at least one alkyl group, are a known class of chemical compound which have been widely used, for example, as a rubber vulcanizing agent. This class of composition can be represented by the following formula:
where R is alkyl, such as lower alkyl containing from one to four carbon atoms in the alkyl group, m is from 1 to 3, preferably 1 or 2, and n, the repeat unit for the depicted structure, can range from about 2 to about 10. The value of the repeat unit n will depend upon the ratio of the reactants used. The value for x, the number of sulfur atoms in the bridge between phenol groups, can range from 1 to about 4. The sulfur ranking depends on the value for x and will be larger if the amount of sulfur introduced into the reaction is larger. If sulfur dichloride is used in accordance with the reaction in Example 1, which follows, x will be about 1 if no additional sulfur is used. If sulfur monochloride is employed, x would be about 2. If a tri- or higher sulfide product is desired, elemental sulfur can be added in addition to the previously described sulfur monochloride or dichloride reagents for reaction with the phenol or alkyl phenol reagent. Further information on how to make such alkyl phenol sulfides can be found in U.S. Pat. No. 2,422,156 which is incorporated herein by reference.
The foregoing type of active ingredient for wood preservation can be incorporated in an effective amount (e.g., from about 1% to about 20%, by weight) in a suitable liquid vehicle along with other desired functional additives for use in the treatment of wood. Included as suitable liquid vehicles are xylene, N-methylpyrrolidinone, and methylene chloride. Examples of the types of functional additives that can be used include supplementary wood preservation chemical(s), surfactant(s), colorant(s), ultraviolet light retardant(s).
The Following Examples further illustrate certain embodiments of the present invention.
REFERENCES:
patent: 2422156 (1947-06-01), Wolf et al.
patent: 3812192 (1974-05-01), Gabler et al.
patent: 3968062 (1976-07-01), Ecsedy
patent: 5925424 (1999-07-01), Goswami et al.
Chemical Abstracts, vol. 106, 155968 (1986).
Y. Inouye, et al., Studies on the Wood Preservatives. I. The Sterilizing Power of O-Cresol Sulfur Resin against Wood Destroying Fungi, Wood Research, Bulletin of the Wood Research Institute; Kyoto University, No. 4, Feb. 1950, pp. 19-23 with English translation.
Doyle Andress K.
Goswami Jagadish C.
Liu Jian-Lin
Akzo Nobel nv
Chen Vivian
Fennelly Richard P.
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