Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Particulate matter
Reexamination Certificate
2001-01-17
2003-04-01
Kiliman, Leszek (Department: 1773)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Particulate matter
C428S405000, C428S407000, C523S201000, C525S288000
Reexamination Certificate
active
06541114
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to composite particles capable of forming a coating excelling in weatherability and, in particular, stain-proof characteristics, a composite particle dispersion composition excelling in film formability, and a method of preparing the composite particle dispersion composition.
2. Description of Background Art
In recent years, pollution-free coating materials have been strongly demanded from the viewpoint of environmental safeguards and health. To deal with this demand, use of aqueous coating materials, in particular, aqueous coating dispersions instead of conventional solvent-type coating materials has progressed and application fields for such aqueous coating dispersions have widened. Accompanying this, the aqueous coating dispersions are required to exhibit higher performance.
Conventionally, (meth)acrylic polymers have been widely used for coating materials as aqueous dispersions because of excellent transparency and film formability. Polysiloxanes excel in weatherability, water repellency, and adhesion to inorganic substrates and have been used in various fields including coating materials as disclosed in Japanese Patent Publication No. 39691/1977. In order to obtain a synergistic effect from excellent performances of these polymer components, Japanese Patent Applications Laid-open No. 45628/1991 and No. 261454/1992 disclose use of composite materials consisting of (meth)acrylic polymers and polysiloxanes as coating materials and the like.
These composite materials of (meth)acrylic polymers and polysiloxanes exhibit good weatherability. However, these composite materials also exhibit insufficient stain-proof characteristics such as resistance to rain streaks when exposed to the outdoors.
Japanese Patent Application Laid-open No. 214747/1992 discloses a self-crosslinking polymer latex composition containing a polyfunctional hydrazine derivative and polymer latex containing organopolysiloxane which is obtained by copolymerizing monomers containing a carbonyl group and other monomers in the presence of hydrolyzable silane. This composition forms a coating excelling in weatherability, stain-proof characteristics, and the like. However, this composition cannot produce a coating retaining weatherability, stain-proof characteristics, and UV-degradation resistance for a long period of time and exhibits insufficient film formability.
As described above, it is very difficult to provide an aqueous dispersion with performance capable of retaining both weatherability and stain-proof characteristics for a long period of time when used as a coating material. Therefore, improvement of the performance and film formability of the aqueous dispersion has been demanded.
Accordingly, an object of the present invention is to provide composite particles used in a dispersion capable of forming a coating excelling in weatherability and, in particular, stain-proof characteristics.
Another object of the present invention is to provide a composite particle dispersion composition capable of forming a coating excelling in weatherability, in particular, stain-proof characteristics and capable of retaining these characteristics for a long period of time.
A further object of the present invention is to provide a method of preparing the composite particle dispersion composition.
SUMMARY OF THE INVENTION
The above objects of the present invention can be achieved by composite particles comprising: (i) polymer particles which comprise 2-70 wt % of a polymer phase (a) of the core and 98-30 wt % of a polymer phase (b) of the shell; and (ii) a polymer of an organosilicon compound or organometallic compound, or both, present at least either on or near the surface of the polymer phase (b); wherein the polymer phase (a) and the polymer phase (b) have different monomer compositions.
In a preferred embodiment of the composite particles of the present invention, each of the polymer phase (a) and the polymer phase (b) is a (meth)acrylic polymer, a (meth)acrylic silicon polymer, a fluorine-containing polymer, a polyurethane, a urethane/acrylic polymer, or a diene polymer.
In another preferred embodiment of the composite particles of the present invention, the polymer (ii) is chemically bonded to the polymer phase (b).
In still another preferred embodiment of the composite particles of the present invention, the organosilicon compound or the organometallic compound is a compound shown by the following formula (1):
R
1
n
M(OR
2
)
z-n
(1)
wherein R
1
represents a hydrogen atom or an organic group having 1-8 carbon atoms (excluding the group represented by OR
2
), R
2
represents an alkyl group having 1-6 carbon atoms, an acyl group having 1-6 carbon atoms, or an aryl group having 6-10 carbon atoms, M represents Si or metal atom with a valence of 3 or more, n is 0 or an integer of 1 or more, z is a valence of M, and z-n is an integer of 2 or more, provided that, when a plurality of R
1
s is present, each R
1
may be the same or different, this also applies to R
2
.
In a further preferred embodiment of the composite particles of the present invention, the content of the polymer (ii) is 0.5-100 parts by weight for 100 parts by weight of the polymer particles (i).
In the above composite particles, the difference in the gel content between the polymer phase (a) and the polymer phase (b) is preferably 5 wt % or more.
In the above composite particles, the difference in the glass transition temperature between the polymer phase (a) and the polymer phase (b) is preferably 5° C. or more.
In the above composite particles, a UV absorbent monomer or a radical scavenging monomer, or both, may be copolymerized with at least either the polymer phase (a) or the polymer phase (b).
The above UV absorbent monomer is preferably a compound selected from the group consisting of p-(meth)acryloxyphenyl salicylate, 2-hydroxy-4-(meth)acryloxybenzophenone, and 2-(2′-hydroxy-5′-(meth)acryloxyethylphenyl)benzotriaole.
The above radical scavenging monomer is preferably a compound selected from the group consisting of 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetr amethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine.
In the above composite particles, the proportion of the UV absorbent monomer or radical scavenging monomer copolymerized in the polymer particles (i) is preferably 0.1-30 wt %.
The composite particles of the present invention preferably have an average particle diameter of 5 &mgr;m or less.
The composite particles of the present invention preferably have a minimum film-forming temperature of the composite particles is 90° C. or less.
The above objects of the present invention can be further achieved by a composite particle dispersion composition comprising: (A) composite particles comprising (i) polymer particles which comprise 2-70 wt % of a polymer phase (a) of the core and 98-30 wt % of a polymer phase (b) of the shell, and (ii) a polymer of at least either an organosilicon compound or organometallic compound present at least either on or near the surface of the polymer phase (b), wherein the polymer phase (a) and the polymer phase (b) have different monomer compositions; and (B) a poor solvent for the composite particles (A).
In the composite particle dispersion composition of the present invention, the weight ratio of the composite particles (A) to the poor solvent (B) (composite particles/poor solvent) is preferably from 5/95 to 70/30.
The above objects of the present invention can be still further achieved by a method of preparing a composite particle dispersi
Katou Minoru
Tsuruoka Katsuhiko
JSR Corporation
Kiliman Leszek
LandOfFree
Composite particles, composite particle dispersion... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Composite particles, composite particle dispersion..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composite particles, composite particle dispersion... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3113034