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
2001-11-30
2003-05-06
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S203000, C525S282000, C525S161000, C525S448000, C524S555000
Reexamination Certificate
active
06559231
ABSTRACT:
The present invention relates to a curing type water base resin composition, more specifically to a curing type water base resin composition of a single liquid type which is excellent in low temperature physical properties and which can readily be cured regardless of coating environment.
In recent years, switching from an organic solvent type over to a water base type has been being expedited in the fields of coating materials, inks and adhesives from the viewpoints of resource saving, environmental sanitation, non-public pollution and non-hazardousness. For example, in water base coating materials in the construction field, required are coating materials which are dried at a room temperature and excellent in coating film performances such as a water resistance, a weatherability and a stain resistance, and emulsion particles having a cross-linkable carbonyl group and acryl base resin compositions comprising a dihydrazide compound are disclosed in, for example, Japanese Patent Application Laid-Open No. 249587/1992 as a resin composition for a water base cold-dryable coating material which satisfies such requirement and is suited to construction use.
Further, resin compositions prepared by further blending the above acryl base resin compositions with water base polyurethane resins are proposed in Japanese Patent Application Laid-Open No. 339542/1993, U.S. Pat. No. 5,614,582 (=EP-A-648,794) and Japanese Patent Application Laid-Open No. 259356/1998 for the purpose to provide the above acryl base resin compositions with a toughness, a coating film elasticity and low temperature physical properties. The above compositions are excellent in a storing property and improve in coating film physical properties by using a water base polyurethane resin in combination, but a cross-linking reaction does not sufficiently proceed depending on coating environment in a certain case. There is, for example, the problem that the water resistance at an initial stage after coating (initial water resistance) is unsatisfactory in coating in the environment in which evaporation of moisture is notably slow as observed when the ambient temperature is low.
Intensive investigations repeated by the present inventors in order to solve the problem described above involved in conventional water base cold-dryable single liquid type coating compositions have resulted in finding that a curing type water base resin composition capable of forming a coating film which is excellent in a water resistance and a curing property even at an initial stage after coating regardless of coating environment can be obtained by introducing a maleimide group cured by irradiation with natural light into a copolymer having a cross-linkable carbonyl group, using a hydrazine compound as a cross-linking agent in combination and using supplementarily photocuring caused by a maleimide group in combination with a cross-linking reaction caused by a carbonyl group/cross-linking agent, and they have come to complete the present invention.
Thus, the present invention provides a curing type water base resin composition comprising:
(I) a copolymer obtained by copolymerizing an ethylenically unsaturated monomer (a) having a maleimide group, an ethylenically unsaturated monomer (b) having a carbonyl group and other ethylenically unsaturated monomer (c) and
(II) a compound having two or more groups per molecule which are the same or different and selected from a hydrazide group, a semicarbazide group and hydrazone group.
Also, the present invention provides the curing type water base resin composition described above further comprising as an additional component:
(III) a copolymer having a carbonyl group and/or
(IV) a water base polyurethane resin having a carbonyl group or a hydrazine group.
The curing type water base resin composition of the present invention shall be explained below in further details.
In the present specification, an acryloyl group or a methacryloyl group is expressed as a (meth)acryloyl group; acrylate or methacrylate is expressed as (meth)acrylate; acrylic acid or methacrylic acid is expressed as (meth)acrylic acid; acrolein or methacrolein is expressed as (meth)acrolein; acrylamide or meth acrylamide is expressed as (meth)acrylamide; and an allyl group or a methallyl group is expressed as a (meth)allyl group.
Copolymer (I)
The copolymer (I) is a copolymer which is obtained by copolymerizing the ethylenically unsaturated monomer (a) having a maleimide groups the ethylenically unsaturated monomer (b) having a carbonyl group and the other ethylenically unsaturated monomers (c) and which has a maleimide group and a carbonyl group in a molecule.
The ethylenically unsaturated monomer (a) having a maleimide group is used in order to introduce into the copolymer (I), a maleimide group for three-dimensionally cross-linking a coating film formed from the resin composition of the present invention by optical dimerization by irradiating with natural light.
Included in such ethylenically unsaturated monomer (a) having a maleimide group is a compound [hereinafter referred to merely as an (imide compound)] having an ethylenically unsaturated group and a cyclic imide group represented by the following Formula (1):
wherein R
1
and R
2
each represent independently a hydrogen atom or an alkyl group, or R
1
and R
2
represent a group forming a carbon ring together with carbon atoms to which they are bonded.
The ethylenically unsaturated group in the imide compound described above includes, for example, a vinyl group, an allyl group and a (meth)acryloyl group, and the (meth)acryloyl group is particularly preferred.
From the viewpoints of the polymerizing property between the imide compounds and the copolymerizing property with other unsaturated monomers, R
1
and R
2
in the Formula (1) described above each are independently alkyl groups, preferably alkyl groups having 4 or less Gcarbon atoms, or groups forming a carbon ring together, for example —CH
2
CH
2
CH
2
— and —CH
2
CH
2
CH
2
CH
2
—, preferably —CH
2
CH
2
CH
2
CH
2
—.
To be specific, the imide compound includes, for example, imide (meth)acrylate represented by the following Formula (2):
wherein R
1
and R
2
are synonymous with those described above; R
3
represents an alkylene group, preferably an alkylene group having 1 to 6 carbon atoms and more preferably ethylene or propylene; R
4
represents a hydrogen atom or methyl; and n is an integer of 1 to 6, preferably 1 or 2 and more preferably 1.
Compounds represented by the following Formulas (3) and (4) can be given as imide (meth)acrylate described above:
wherein R
4
and R
5
each represent independently a hydrogen atom or methyl; R
6
and R
7
each represent independently an alkyl group having 4 or less carbon atoms; and n is an integer of 1 to 6.
Imide (meth)acrylate is a conventionally known compound and can be produced from an acid anhydride, aminoalcohol and (meth)acrylic acid by methods described in, for example, K. Kato et al., Organic Synthestic Chemistry Association Report, 30 (10), 897, (1972); Javier de Abajo et al., Polymer, vol. 33 (5), 1090, (1992); Japanese Patent Application Laid-Open No. 53119/1981 and Japanese Patent Application Laid-Open No. 242569/1989.
The ethylenically unsaturated monomer (b) having a carbonyl group is used in order to introduce a carbonyl group into the copolymer (I), and the above carbonyl group is subjected to cross-linking reaction with a functional group in the compound (II) described later to supplement the cross-linking of the coating film by the copolymer (I) when optical cross-linking by the maleimide group described above is unsatisfactory.
Suited as the above ethylenically unsaturated monomer (b) having a carbonyl group is a monomer having at least one carbonyl group selected from an aldehyde group and a keto group and a polymerizable double bond in a molecule, and to be specific, it includes, for example, (meth)acrolein, formylstyrol, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone and vinyl butyl ketone) and di
Hasegawa Mitsutaka
Inukai Hiroshi
Ishihara Yushichi
Nakamura Koki
Numa Nobushige
Kansai Paint Co. Ltd.
Sastri Satya
Wu David W.
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