Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-05-30
2004-03-16
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S205000, C525S326800, C525S327600, C524S850000, C524S859000
Reexamination Certificate
active
06706818
ABSTRACT:
This invention relates to a curable resin composition, in more detail, to a resin composition for one-pack type water-based paint which is readily cured regardless of coating environment.
Aqueous dispersion of acrylic copolymer has mainly been used as water-based cold-dryable one-pack type paint for the interior and exterior decoration of building. A coating film formed from paint which contains aqueous dispersion of acrylic copolymer is excellent in weatherability and hardness, but is poor in water resistance and stain resistance. On the other hand, there has been an increasing market demand for paint which gives good film elasticity and toughness, and, thus, it is under consideration to employ urethane resin for water-based paint. As an example of water-based paint which has urethane function, Japanese Patent Application Laid-Open No. 259356/1998 and Japanese Patent Application Laid-Open No. 50002/1999 have each disclosed a resin composition for water-based paint which contains aqueous carbonyl group-containing polyurethane resin and hydrazide compound. Said composition has no problem in coating workability, and gives a coating film which is excellent in water-resistance, weatherability and low-temperature physical properties. This resin composition has, however, a defect that crosslinking reaction does not proceed sufficiently depending on coating environment. For instance, in the case of paint application under such circumstances as low temperature where moisture evaporation is markedly slow, this composition gives only poor water-resistance (initial water-resistance) at an initial stage after applied.
Inventors of this invention have assiduously studied how to resolve the above-mentioned problems of conventional aqueous urethane resin-containing resin composition for cold-dryable one-pack type water-based paint, and have now found out that a resin composition which comprises both a copolymer of unsaturated group-containing urethane prepolymer, maleimide group-containing ethylenically unsaturated monomer and crosslinkable carbonyl group-containing ethylenically unsaturated monomer, and a hydrazide compound is capable of forming a coating film which is excellent in water-resistance and curability even at an initial stage after applied regardless of coating environment, and, thus, this invention has been completed.
This invention provides a curable resin composition which characteristically comprises both copolymer (I) which is produced from the copolymerization of unsaturated group-containing urethane prepolymer (A) which is obtained from a reaction of diisocyanate compound (a), glycol compound (b), carboxyl group-containing glycol compound (c) and hydroxyl group-containing ethylenically unsaturated monomer (d), with maleimide group-containing ethylenically unsaturated monomer (e), carbonyl group-containing ethylenically unsaturated monomer (f) and another ethylenically unsaturated monomer (g), and compound (II) which has, per molecule, two or more same or different functional groups selected from hydrazide group, semicarbazide group and hydrazone group.
The following gives a more detailed explanation of the curable resin composition of this invention.
Incidentally, in the present specification, acryloyl group and methacryloyl group are expressed as (meth)acryloyl group; acrylate and methacrylate are expressed as (meth)acrylate; acrylic acid and methacrylic acid are expressed as (meth)acrylic acid; acrolein and methacrolein are expressed as (meth)acrolein; acrylamide and methacrylamide are expressed as (meth)acrylamide; and allyl group and methallyl group are expressed as (meth)allyl group.
Copolymer (I)
Copolymer (I) which is used for the curable resin composition of this invention is produced from the copolymerization of unsaturated group-containing urethane prepolymer (A) which is obtained from a reaction of diisocyanate compound (a), glycol compound (b), carboxyl group-containing glycol compound (c) and hydroxyl group-containing ethylenically unsaturated monomer (d), with maleimide group-containing ethylenically unsaturated monomer (e), carbonyl group-containing ethylenically unsaturated monomer (f) and another ethylenically unsaturated monomer (g).
Diisocyanate compound (a) which is used for the production of said unsaturated group-containing urethane prepolymer (A) includes aliphatic, alicyclic and aromatic compounds having two isocyanate groups in a molecule. Concrete examples are 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 4,4′-diphenylmethanediisocyanate, m-phenylenediisocyanate, xylylenediisocyanate, tetramethylenediisocyanate, 2,2,4-trimethylhexanediisocyanate, hexamethylenediisocyanate, lysine-diisocyanate, 1,4-cyclohexylenediisocyanate, 4,4′-dicyclohexyl-methanediisocyanate, 3,3′-dimethyl-4,4′-biphenylenediisocyanate, 3,3′-dimethoxy-4,4′-biphenylenediisocyanate, 3,3′-dichloro-4,4′-biphenylenediisocyanate, 1,5-naphthalenediisocyanate, 1,5-tetrahydronaphthalenediisocyanate and isophoronediisocyanate, among which aliphatic diisocyanate such as tetramethylenediisocyanate, 2,2,4-trimethylhexanediisocyanate, hexamethylenediisocyanate and lysine-diisocyanate, and alicyclic diisocyanate such as 1,4-cyclohexylenediisocyanate, 4,4′-dicyclohexyl-methanediisocyanate and isophoronediisocyanate, are in particular preferable.
Glycol compound (b) includes low molecular weight glycols, high molecular weight glycols, polyesterpolyols and polycarbonatepolyols, which may be used either separately or in combination of two or more kinds.
Examples of said low molecular weight glycols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, octanediol, tricyclo-decanedimethylol, hydrogenated bisphenol A, cyclohexane-dimethanol and 1,6-hexanediol. Examples of said high molecular weight glycols include polyethylene glycol, polypropylene glycol and polytetramethylene glycol.
The above-mentioned polyesterpolyols include those obtained by a reaction between glycol components and dicarboxylic acid components, which can readily be produced by a conventionally known method such as esterification reaction and transesterification reaction. Said polyesterpolyols also include polyesterdiols which are obtained by ring-opening reaction of cyclic ester compounds such as &egr;-caprolactone, and copolycondensation polyesters thereof as well.
The above-mentioned carboxyl group-containing glycol compound (c) includes 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid and polyester-polyols or polyetherpolyols obtained by the condensation thereof. Said carboxyl group-containing glycol compound (c) may be used in combination with hydroxycarboxylic acid such as 12-hydroxystearic acid, paraoxybenzoic acid and salicylic acid.
Hydroxyl group-containing ethylenically unsaturated monomer (d) is used for introducing an unsaturated group into polyurethane resin skeleton. Examples include (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol mono(meth)acrylate, &egr;-caprolactone polyaddition product of hydroxyethyl (meth)acrylate, &bgr;-methyl-&dgr;-valerolactone polyaddition product of hydroxyethyl (meth)acrylate, glycerol mono(meth)acrylate and glycerol di(meth)acrylate; allyl compounds such as allyl alcohol, glycerol monoallyl ether and glycerol diallyl ether; and alkylene oxide adducts thereof having 2 to 4 carbon atoms (number of moles of added alkylene oxide is usually 0 to 30, preferably 20 to 30).
For the purpose of the blocking of excess isocyanate groups and the control of the concentration of unsaturated group, a monohydric alcohol may be used, where necessary, in combination with diisocyanate compound (a), glycol compound (b), carboxyl group-containing glycol compound (c) and hydroxyl group-containing ethylenically unsaturated monomer (d)
Hasegawa Mitsutaka
Inukai Hiroshi
Ishihara Yushichi
Numa Nobushige
Sugishima Masami
Gorr Rachel
Kansai Paint Co. Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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