Polyacrylate Derivative

1. Field of the Invention

The present invention relates to a new polyacrylate derivative, and more particularly it relates to a quaternary ammonium salt of polyacrylic acid or polymethacrylic acid.

2. Description of the Prior Art

Among the known quaternary ammonium salt of high molecular weight compounds are quaternary ammonium salts of carboxymethylcellulose such as the dimethyllaurylcetylammonium salt (West German Pat. No. 1,103,336), trimethyloctadecylammonium salt (U.S. Pat. No. 2,881,074), dodecyldimethyl (3,4-dichlorobenzyl)ammonium salt [Deut. Apotheker-Ztg., 106,(35), 1206-8, (1966)], tetradecylpyridinium salt and cetyltrimethylammonium salt [Pham. Ind., 37,(2), 100, (1976)]. Nevertheless, nothing has heretofore been known about a quaternary ammonium salt of a polymer, such as a polyacrylate derivative as is described in to the present invention.

The present invention provides a polyacrylate derivative represented by the formula: ##STR1## (where R is a hydrogen atom or methyl group; R.sub.1 to R.sub.4 are groups of which two are methyl groups, one is a benzyl group, and the remaining one is a tetradecyl group or p-1,1,3,3-tetramethylbutylphenoxyethoxyethyl group; and n is a numeral from 50 to 20,000.)

The compounds of the present invention are effective for preventing the accumulation or attachment of marine organisms (e.g., periphytons such as seaweeds or shellfishes) on ship's bottom, fishing nets or various marine structures. In addition, they show a very low degree of toxicity.

FIG. 1 and FIG. 2 are infrared absorption spectra of tetradecyldimethylbenzylammonium salt of polyacrylic acid and benzethonium salt of polyacrylic acid, respectively, which are the compounds of the invention. FIG. 3 and FIG. 4 are .sup.1 H-NMR spectra of tetradecyldimethylbenzylammonium salt of polyacrylic acid and benzethonium salt of polyacrylic acid, respectively.

The polyacrylate derivative of the present invention can be obtained by reacting an alkali metal salt (e.g., sodium salt) of polyacrylic acid (or polymethacrylic acid) and a corresponding quaternary ammonium halide in approximately equimolar amount in an aqueous solution. The preferred polyacrylic acid or polymethacrylic acid is one which has a degree of polymerization in the range of about 50 to 20,000 (measured by osmometry). In a case where the polyacrylate derivative is intended for use as an agent for preventing the accumulation or attachment of marine organisms such as periphyton, it is preferred to employ a polyacrylic acid or polymethacrylic acid raw material having a degree of polymerization in the range of about 100 to 1000, because one having an excessively high degree of polymerization shows an undesirably high viscosity.

The reaction gives a product sparingly soluble in water, which precipitates. The precipitate can be collected by filtration and if necessary is purified. The purification can be easily conducted by washing with water; or by dissolving in an organic solvent (e.g., a lower alkanol such as ethanol or isopropanol, a ketone such as methyl isobutyl ketone or a benzene anologue such as benzene, toluene or xylene) containing water (10% or less), followed by addition of water to re-precipitate.

When the polyacrylate derivative of the invention is used as an agent for preventing the accumulation or attachment of periphyton, it is conventionally formulated in the form of a paint. The paint is usually composed of an organic solvent (as mentioned above) and a solution of a conventional resin for painting such as acrylic resins. The concentration of the polyacrylate derivative in the paint is usually about 2-30% by weight. Such paint can be applied to the subject by dip coating or direct coating.

To further illustrate the invention, and not by way of limitation, the following examples are given.

In a 1-liter three-neck flask was placed 500 ml of water and then 18.8 g (0.2 mol) of sodium polyacrylate having a degree of polymerization of 300. Dissolution was effected by heating (at 40.degree. C.) and stirring. An equivalent of each of the quaternary ammonium compounds shown in Table 1 was dissolved in 370 ml of water. The resulting aqueous solution was slowly added with stirring to the aqueous solution of sodium polyacrylate. Stirring was continued for 30 minutes. The resulting precipitate was filtered off and fully washed with water, followed by vacuum drying at normal temperature. Thus there were obtained two kinds of quaternary ammonium salts of polyacrylic acid. Their solubility in solvents and compatibility with resins are shown in Tables 1 and 2 below, respectively.

The thus obtained tetradecyldimethylbenzylammonium salt of polyacrylic acid and benzethonium polyacrylic acid were examined by elemental analysis, infrared absorption spectrometry, and .sup.1 H-NMR spectrometry. The results are shown below. (Refer to FIGS. 1 to 4).

An antifouling paint was prepared from 30 g of tetradecyldimethylbenzylammonium salt of polyacrylic acid obtained in Example 1, 175 g of acrylate paint (containing 70 g of acrylic resin LR-117 made by Mitsubishi Rayon Co., Ltd.), and 560 g of isobutanol. The paint was applied to a polyethylene fishing net by dipping. After drying for two days at normal temperature, the fishing net was immersed in seawater for two months. The accumulation or attachment of marine organisms on the fishing net was examined. The results are shown in Table 3.