Stock material or miscellaneous articles – Composite – Of silicon containing
Robertson, Jeffrey B. (Department: 1712)
Stock material or miscellaneous articles
Of silicon containing
C427S387000, C106S287100, C524S432000, C524S588000, C525S474000, C525S926000, C528S025000, C528S026000, C528S029000, C528S035000, C424S078090
The present invention relates to a novel (poly)oxyalkylene block silyl ester copolymer. More particularly, the present invention is concerned with a (poly)oxyalkylene block silyl ester copolymer which, when used as a vehicle of coating composition or paint, enables forming a coating having excellent transparency and being excellent in foul removing performance, i.e., capability of easily removing foul from a coating surface.
Ship bottoms, underwater structures, fishing nets and the like are likely to have their appearance and function damaged by the adhesion to surface and propagation of various aquatic organisms including shellfishes such as oysters, hard-shelled mussels and barnacles, plants such as laver (seaweeds) and bacteria which is caused when they are exposed to water or seawater for a prolonged period of time.
In particular, when such an aquatic organism adheres to a ship's bottom and propagates, it may occur that the surface roughness of the ship's bottom is increased to thereby lower the speed of the ship and increase the fuel consumed by the ship. Removing the aquatic organism from the ship bottom takes thousands of man-hours, so that many labors and much time are needed for this work. Also, when bacteria adhere to, for example, an underwater structure and propagate and, further, slime (sludgy matter) adheres thereto to cause putrefaction, or when a large sticky organism adheres to the surface of an underwater structure of, for example, steel and propagates to thereby damage the coating for corrosion prevention provided on the underwater structure, there is the danger that damages such as deterioration of the strength and function of the underwater structure and thus marked shortening of the life thereof are invited.
In order to avoid the above damages, for example, an antifouling paint containing a copolymer of tributyltin methacrylate and methyl methacrylate or the like and cuprous oxide (Cu
O) has been applied to ship bottoms, etc. This copolymer of the antifouling paint is hydrolyzed in the seawater to thereby liberate organotin compounds such as bistributyltin oxide (tributyltin ether of the formula Bu
wherein Bu is a butyl group) and tributyltin halides (Bu
SnX wherein X is a halogen atom), so that an antifouling effect is exerted. Furthermore, the copolymer hydrolyzate per se has water-solubility and thus is dissolved in the seawater, as a result, no residue of hydrolyzate is left on the surface of the ship bottom coating, and then the new paint film surface in which the copolymer is not hydrolyzed is exposed to maintain the antifouling effect for long. The antifouling paint having such a performance is called as “hydrolyzable self-polishing paint”.
However, the above organotin compounds are so highly toxic that apprehensions are being entertained with respect to marine pollution, occurrence of anomalous fish and anomalous shellfish and adverse effects on ecosystem through food chain. Therefore, the development of a nonstannic antifouling paint having excellent antifouling properties is desired as a substitute therefor.
For example, antifouling paints based on silyl esters as described in Japanese Patent Laid-open Publication Nos. 4(1992)-264170 (reference (1)), 4(1992)-264169 (reference (2)) and 4(1992)-264168 (reference (3)) can be mentioned as the above nonstannic antifouling paint. However, these antifouling paints have problems that not only are their antifouling capabilities poor but also cracking and peeling are likely to occur as pointed out in Japanese Patent Laid-open Publication Nos. 6(1994)-157941 (reference (4)) and 6(1994)-157940 (reference (5))
Further, Japanese Patent Laid-open Publication No. 2(1990)-196869 (reference (6)) teaches an antifouling paint comprising a blocked acid-functionality copolymer (A) which is obtained by copolymerizing trimethylsilyl methacrylate, ethyl methacrylate and methoxyethyl acrylate in the presence of an azo initiator and which contains carboxyl groups blocked with trimethylsilyl groups and a polycationic compound (B). However, the coating film obtained from the antifouling paint has a drawback in that the cracking resistance thereof is not fully satisfactory.
Published Japanese Translation of PCT Patent Applications from Other States, No. 60(1985)-500452 (reference (7)) and Japanese Patent Laid-open Publication No. 63(1988)-215780 describe a resin for antifouling paint which is obtained by copolymerizing a vinyl monomer having an organosilyl group, such as a trialkylsilyl ester of (meth)acrylic acid, with another vinyl monomer and which has a number average molecular weight of 3000 to 40,000. It is further described that the resin can be blended with an organic water binder such as trimethyl orthoformate, an antifouling agent such as cuprous oxide and a pigment such as red iron oxide. However, as described in the above Japanese Patent Laid-open Publication No. 6(1994)-157940 (reference (5)), this resin for antifouling paint has drawbacks in that it is likely to gelate during the storage thereof and that the coating film formed from the antifouling paint is poor in cracking and peeling resistances.
Japanese Patent Publication No. 5(1993)-32433 corresponding to the above Published Japanese Translation of PCT Patent Applications from Other States, No. 60(1985)-500452 (reference (7)) discloses an antifouling paint comprising a poison (a) and a polymer binder (b) having a repeating unit of the formula (—CH
—CX(COOR)—(B)— wherein X is H or CH
, R is SiR′
in which R′ is an alkyl group, etc. and B is an ethylenically unsaturated monomer residue), which polymer binder has a specified hydrolysis rate. Further, it is described that the antifouling paint can contain a solvent, a water-sensitive pigment component, an inert pigment, a filler and a retarder. However, the coating film obtained from the antifouling paint described in the publication has a drawback in that its cracking resistance is poor.
Japanese Patent Laid-open Publication No. 7(1995)-18216 (reference (8)) discloses a coating composition comprising as principal components a polymer (A) from an organosilicon-containing monomer A having in its molecule a triorganosilicon ester group represented by the formula —COO—SiR
(wherein each of R
is, for example, an alkyl group having 1 to 18 carbon atoms) and copper or a copper compound (B), which coating composition contains as an essential component other than the components (A) and (B) a silicon compound having an alkoxy group (C) represented by the formula:
wherein each of R
represents, for example, a hydrogen atom, or an alkoxy group or cycloalkoxy group having 1 to 18 carbon atoms; R
represents, for example, an alkyl group having 1 to 18 carbon atoms; and n is an integer of 1 to 3. In the publication, it is described that a copolymer AB obtained by copolymerizing the above organosilicon-containing monomer A and a vinyl monomer copolymerizable therewith B may be contained in the coating composition. As the monomer B, there are mentioned (meth)acrylic esters such as methyl (meth)acrylate, ethyl (meth)acrylate and dimethylaminoethyl (meth)acrylate.
However, the coating film obtained from the coating composition described in the publication has a drawback in that it is inferior in cracking resistance and antifouling properties, in particular, antifouling properties in highly fouling environment. The expression “in highly fouling environment” used herein means such situations that a ship or an underwater structure is allowed to stand still in a nutrious sea area such as an inland sea or other like sea area, or, with respect to a ship, service and anchorage are repeated frequently or navigation is conducted at a speed as low as about 10 knots or less.
Japanese Patent Laid-open Publication No. 7(1995)-102193 (reference (9)) discloses a coating composition comprising as essential components an antifouling agent and a copolymer obtained from a monomer mixture containing mon
Chugoku Marine Paints Ltd.
Robertson Jeffrey B.
Sherman & Shalloway
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