Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-08-26
2001-08-07
Sanders, Kriellion (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S544000, C428S422000
Reexamination Certificate
active
06271283
ABSTRACT:
The present invention relates to an aqueous antifouling composition which is capable of imparting an antifouling property excellent in durability to a substrate even when dried at room temperature, a process for its production and a product treated therewith.
Heretofore, an antifouling composition of a fluorine type has been used for antifouling purposes for fiber products such as working wears or rental sheets. A typical antifouling composition may be an antifouling composition having a copolymer obtained by copolymerizing an addition polymerizable monomer having a perfluoroalkyl group, dissolved in an organic solvent. As such an organic solvent, a halogen type solvent such as a chlorofluorocarbon or a hydrochlorocarbon has been used. However, with a view to protecting the ozone layer, such a halogen type solvent has been substituted by a ketone type solvent, an ester type solvent or a petroleum type solvent, in recent years. Further, conventional organic solvent type antifouling compositions including a case where a halogen type solvent has been used, used to have a problem such that the antifouling property tends to deteriorate by a few times of washing or dry cleaning or by abrasion during the use. Furthermore, antifouling compositions employing such organic solvents, have had a problem such that they had strong odors, or they are inflammable.
On the other hand, also known is an aqueous type antifouling composition which contains no or little organic solvent, such as a water and oil repellant (JP-A-6-240239) having dispersed in an aqueous medium a copolymer obtained by polymerizing a (meth)acrylate having a polyfluoroalkyl group, a blocked isocyanate group-containing (meth)acrylate and a hydroxyl group-containing (meth)acrylate, or an antifouling agent (JP-A-7-279687) having dispersed in an aqueous medium a copolymer obtained by polymerizing a (meth)acrylate having a polyfluoroalkyl group, a blocked isocyanate group-containing (meth)acrylate and a polyoxyalkylene chain-containing (meth)acrylate.
In this specification, the term “(meth)acrylate” means acrylate and/or methacrylate. The same applies to a term such as “(meth)acrylic acid”. Further, “antifouling agent” is meant also for a water and oil repellant and may be one which imparts water and oil repellency to a substrate to provide an antifouling property.
Such an aqueous antifouling composition is superior in that it has overcome the drawbacks of an organic solvent type antifouling composition, but it is a cross-linkable antifouling agent and is required to be subjected to heat treatment for crosslinking in order to treat a substrate. However, in some cases such as a case where antifouling treatment is carried out simply at home or at office, it may be difficult to carry out such heat treatment. If a substrate is treated with such an aqueous antifouling composition and dried at room temperature, no adequate antifouling property will be obtained.
It is an object of the present invention to provide an aqueous antifouling composition which contains no or little solvent and whereby an antifouling property can be obtained even by room temperature treatment, and durability of the antifouling property is excellent.
To accomplish the above object, the present invention provides an aqueous antifouling composition comprising fine particles of a copolymer which comprises the following polymer units (a), (b) and (c) and which has a glass transition temperature of at most 5° C., and an aqueous medium in which the fine particles are dispersed:
(a) polymer units of a (meth)acrylate having a polyfluoroalkyl group,
(b) polymer units of an alkyl acrylate wherein the carbon number of the alkyl group is from 2 to 12, and
(c) polymer units of a (meth)acrylic monoester of a polyol.
Further, the present invention provides the above aqueous antifouling composition, wherein the copolymer comprises the polymer units (a), (b) and (c), and polymer units (d) which are different from any of the polymer units (a), (b) and (c).
Still further, the present invention provides the above aqueous antifouling composition, which further contains an emulsifier.
The present invention also provides a process for producing an aqueous antifouling composition, which comprises copolymerizing at least three monomers which comprise the following monomers (a), (b) and (c) as essential components and whereby the glass transition temperature of a copolymer obtainable is at most 5° C., in an aqueous medium in the presence of an emulsifier, and diluting a dispersion thereby obtained:
(a) a (meth)acrylate having a polyfluoroalkyl group,
(b) an alkyl acrylate wherein the carbon number of the alkyl group is from 2 to 12, and
(c) a (meth)acrylic monoester of a polyol.
Further, the present invention provides the above process wherein at least four monomers which comprise the monomers (a), (b) and (c) and a monomer (d) which is different from any one of the monomers (a), (b) and (c), are copolymerized.
The present invention further provides an antifouling method which comprises applying the above-mentioned aqueous antifouling composition to a substrate, followed by drying at room temperature.
Still further, the present invention provides a product treated by the above-mentioned antifouling method.
According to the present invention, it is possible to impart an excellent antifouling property to a substrate by applying the antifouling composition to the substrate, followed by drying at room temperature. Further, the antifouling property is long lasting or durable, such that the antifouling property will not substantially decrease by e.g. abrasion during the use or will rarely be lowered by washing or dry cleaning.
Now, the present invention will be described in detail with reference to the preferred embodiments. Firstly, the copolymer used in the present invention and its polymer units (a), (b), (c) and (d) will be described.
In the following description, a polyfluoroalkyl group will be represented by “a R
f
group”. Further, as described above, the monomers corresponding to the polymer units (a) to (d) will be represented by monomers (a) to (d), respectively.
The specific copolymer used in the present invention is a polymer having a glass transition temperature of at most 5° C. With a copolymer having a glass transition temperature exceeding 5° C., the object of the present invention can not be accomplished even if it contains the polymer units (a) to (c) or similar polymer units. Namely, even if antifouling composition containing a copolymer having a glass transition temperature exceeding 5° C., is applied to a substrate and dried at room temperature, a coating film of the copolymer can hardly be formed on the substrate surface. Even if a coating film is formed, the bond strength between the coating film and the substrate tends to be inadequate, and the durability of the antifouling property tends to be poor.
The glass transition temperature of the copolymer can be adjusted to a level of at most 5° C. by adjusting the proportions and types of the polymer units. For example, if polymer units of an alkyl methacrylate are contained in a relatively large amount instead of polymer units (b), a copolymer tends to have a glass transition temperature exceeding 5° C. Even with polymer units of an alkyl acrylate, if the carbon number of the alkyl group is large, the copolymer likewise tends to have a glass transition temperature exceeding 5° C.
In the present invention, the polymer units (b) do not include the polymer units (a), and the polymer units (c) do not include the polymer units (a) or a polymer units (b). Likewise, the monomer (b) does not include the monomer (a), and the monomer (c) does not include the monomer (a) or the monomer (b).
The polymer units (a) are polymer units of a (meth)acrylate having a R
f
group. The (meth)acrylate having a R
f
group is a compound wherein the R
f
group is present in the alcohol residue moiety of the (meth)acrylate.
The R
f
group is a group having at least two hydrogen atoms of an alkyl group substituted by fluorine atoms. The carbon number
Maekawa Takashige
Omori Yuichi
Shimada Toyomichi
Asahi Glass Company Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Sanders Kriellion
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