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
2002-03-12
2004-03-02
Mullis, Jeffrey (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...
C525S066000
Reexamination Certificate
active
06699932
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Technical Field to which the Invention Belongs
The present invention relates to a binder resin composition for high-solid primer to be used for the purpose of protection or beautiful ornament of polyolefinic resins, for example, polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, etc.
2. Prior Arts
Because of high productivity, broad freedom in design and many advantages such as light weight, antirust and shock resistance, plastics are used very frequently as materials of automotive parts, electric parts, building materials, food packaging films, etc. Above all, because of low price and many excellent properties such as moldability, chemical resistance, heat resistance, water resistance and good electrical characteristics, polyolefinic resins are used extensively as industrial materials, and are one of materials that the growth of demand is most expected in future.
Different from synthetic resins with polarity such as polyurethane resin, polyamide resin, acrylic resin and polyester resin, however, polyolefinic resins are nonpolar and crystalline, hence they have drawbacks of difficult painting and adhesion. For the painting and adhesion of such polyolefinic resins with difficult adherence, low chlorinated polyolefins with strong adherence to polyolefinic resins are used as binder resins.
For example, chlorinated polypropylene or chlorinated propylene-&agr;-olefin copolymer containing carboxylic acid and/or carboxylic anhydride (Japanese Unexamined Patent Publication Nos. Sho 57-36128 and Sho 59-166534, Japanese Patent Publication No. Sho 63-36624), composition having modified copolymer graft copolymerized with &agr;,&bgr;-unsaturated vinyl monomer containing hydroxyl group onto styrene•conjugated diene block copolymer followed by further chlorination as an essential component (Japanese Unexamined Patent Publication Nos. Hei 4-248845 and Hei 5-25405), composition having chlorinated product of graft modified styrene-isoprene block copolymer as an essential component (Japanese Unexamined Patent Publication No. Hei 5-25404), composition having chlorinated product of graft modified propylene•ethylene•&agr;-olefin random copolymer as an essential component (Japanese Unexamined Patent Publication Nos. Hei 5-112750 and Hei 5-112751), method for crosslinking carboxyl group-containing chlorinated polyolefin with epoxy resin (Japanese Patent Publication Nos. Sho 63-50381 and Hei 01-16414, Japanese Unexamined Patent Publication No. Hei 8-100032), composition having modified chlorinated polyolefin obtained by reacting carboxyl group-containing chlorinated polyolefin with low-molecular diol or low-molecular compound with hydroxyl group and amino group as an essential component (Japanese Unexamined Patent Publication Nos. Hei 7-247381 and Hei 7-247382), composition mixed carboxyl group-containing chlorinated polyolefin with acrylic modified chlorinated polyolefin (Japanese Unexamined Patent Publication No. Hei 10-158447), carboxyl group-containing chlorinated polyolefin with particular molecular weight distribution (Japanese Unexamined Patent Publication No. 2000-198807), etc. are proposed.
In recent years, volatile organic compounds (VOC) contained in paint and ink are desired to be reduced, since they become the source of air pollution. As one of reducing methods, high solidification of paint (primer) and ink can be considered.
However, if conventional compositions aforementioned are highly solidified, then the viscosity of primer increases because of too high molecular weight, making the spray painting impossible. Hence, they cannot be used as binder resins for high-solid primers.
For using these compositions as high-solid primers, a method for mixing low molecular weight alkyd resin, acrylic resin, polyester resin, polyurethane resin, etc. is considered. However, since these low molecular weight resins are liable to dissolve into gasohol (a mixed solution of gasoline with alcohol added with 10% lower alcohol such as methanol or ethanol to regular gasoline), they have drawbacks of decreasing gasohol resistance. Besides, the gasohol resistance is an index that becomes a criterion of solvent resistance and is measured by soaking a painted plate into gasohol to judge whether is good or poor by the time until the coated film peels off.
There, for solving said problem, the inventors proposed a binder resin composition for high-solid primer, characterized by containing carboxyl group-containing chlorinated polyolefin with particular molecular weight distribution and ketonic resin (Japanese Patent Application No. 2000-239697). This method was excellent in the gasohol resistance, but the high-octane gasohol resistance that uses a mixed solution of high-octane gasoline consisting of regular gasoline and toluene with alcohol could not be satisfied.
SUBJECT TO BE SOLVED BY THE INVENTION
The invention provides a binder resin composition for high-solid primer excellent not only in the adherence and gasohol resistance, but also in the high-octane gasohol resistance, to be used for painting moldings, sheets, etc. of polyolefinic resin.
MEANS TO SOLVE THE SUBJECT
The primer composition of the invention to solve said subject is a binder resin composition for high-solid primer, characterized by formulating 10 to 200 parts by weight of (A-3) shown below to 100 parts by weight of a mixture of (A-1) with (A-2) shown below within a range of mixing ratio by weight of (A-1/A-2) of 90/10 to 50/50.
(A-1): Carboxyl group-containing chlorinated polyolefin graft copolymerized with 1 to 10% by weight of at least one kind of unsaturated carboxylic acid monomer selected from carboxylic acids and/or carboxylic anhydrides onto polyolefin (I), and then chlorinated to a chlorine content of 10 to 30% by weight, the carboxyl group-containing chlorinated polyolefin (II) having not more than 2% by weight of component with weight average molecular weight of 2,000 being low-molecular weight region of said carboxyl group-containing chlorinated polyolefin and ratio (M
w
/M
n
) of weight average molecular weight (M
w
) to number aver-age molecular weight (M
n
) of 1.5 to 3.5.
(A-2): Ketonic resin with number average molecular weight of 500 to 2,000.
(A-3): Combination of one set or two or more sets selected from alcoxylated melamine and carbamate group-containing compound, alcoxylated melamine and hydroxyl group-containing compound, and isocyanate group-containing compound and hydroxyl group-containing compound.
EMBODIMENT TO PUT THE INVENTION INTO PRACTICE
In following, the invention will be explained in detail.
In the invention, (A-1) and (A-2) form the skeleton of binder resin. (A-1) is a component to provide the adherence to polyolefin and (A-2) is a low-molecular weight component indispensable for high solidification. (A-3) is a component that causes the crosslinking reaction when baking upper paint and is used for improved high-octane gasohol resistance.
Explanation on (A-1)
The carboxyl group-containing chlorinated polyolefin (II) to be used in the invention can be obtained by melting polyolefin (I) under heating, decreasing viscosity or degrading it through thermal decomposition, if need be, graft copolymerizing with unsaturated carboxylic acid monomer of carboxylic acid and/or carboxylic anhydride onto it batchwise or continuously in the presence of radical generator, and then chlorinating. Also, it can be obtained by dissolving polyolefin (I) into sol-vent at 100° C. or higher in a reactor equipped with stirrer or autoclave, graft copolymerizing with unsaturated carboxylic acid monomer in solution in the presence of radical generator, and then chlorinating.
For the raw material polyolefins (I), crystalline polypropylene, noncrystalline polypropylene, propylene-&agr;-olefin copolymer, etc. can be used solely or by mixing two or more kinds. In particular, from the points of workability and adhesiveness of binder resin, crystalline polypropylene with weight average molecular weight of 10,000 to 150,000, propylene-&agr;-olefin c
Ozaki Keizo
Urata Keiji
Mullis Jeffrey
Nippon Paper Industries Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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