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
2001-02-23
2003-05-13
Seidleck, James J. (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...
C525S069000, C525S301000, C525S263000
Reexamination Certificate
active
06562901
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polyolefin resin composition modified with a (co)polymer prepared from a copolymerizable monomer mixture comprising an &agr;,&bgr;-monoethylenically unsaturated monomer and other copolymerizable monomer. More specifically, the invention relates to the resin composition used for a coating or primer of untreated polyolefin resin films, sheets and molded articles, or an adhesive.
BACKGROUND ART
Conventionally, polyolefin resins have good productivity, excellent moldability and many other advantages such as light weight, corrosion prevention and impact resistance, and are thus widely used for interiors and exteriors of automobiles and ships, home electrical appliances, furnitures, miscellaneous goods and building materials.
These polyolefin resin molded articles generally differ from polar synthetic resins represented by a polyurethane resin, polyamide resin, acrylic resin and polyester resin, and are nonpolar and crystalline. Consequently, general purpose coatings and adhesives are very difficult to coat or adhere these polyolefin resin molded articles.
As a result, in order to coat or adhere polyolefin resin molded articles, surface adhesion has been improved by primer treatment or activation of the surface. For example, automotive bumpers have enhanced surface adhesion to the coated film by etching treatment with a halogen based organic solvent such as trichloroethane, or desired coating or adhesion has been carried out after pretreatment such as corona discharge, plasma arc or ozone treatment.
However, these conventionally known coating and adhesion methods using a general purpose resin composition required high equipment cost and long application time, and additionally, lead to irregular finish and tend to cause local difference on the state of treated surface.
In order to solve the above problems, coating compositions have conventionally been proposed. For example, a composition obtained by introducing maleic acid into polyolefin has been disclosed in JP-B-62-21027/1987, and a composition having chlorinated polyolefin as a primary component has been disclosed in JP-B-50-10916/1975. However, these compositions are poor in weatherability, though excellent in adhesion properties to polyolefin molded articles. As a result, uses are usually limited to primer or to places where weatherability is not desired. When these compositions are used for coating places where weatherability is needed, a top coat is usually applied by using a two component system which requires complex operation.
Consequently, development of a coating has been carried out on a one component finishing system which can exhibit good adhesion properties to the material without any pretreatment and also has excellent weatherability. For example, a resin obtained by copolymerizing an acryl-based monomer with chlorinated polyolefin has been described in JP-A-58-71966/1983. A coating composition of a hydroxyacryl-chlorinated polyolefin copolymer and an isocyanate compound has been disclosed in JP-A-59-27968/1984.
Other proposals which have been made in the field are a process for introducing an unsaturated bond into polyolefin (JP-A-1-123812/1989 and 2-269109/1990), a process for introducing organic peroxide (JP-A-1-131220/1989) and a process for using bifunctional organic peroxide (JP-A-64-36614/1989). Any of these proposals are designs for improving reactivity of polyolefin with a radically polymerizable, unsaturated monomer.
However, in the above resin composition and the preparation process of the same, the reaction must be, in many cases, carried out in a dilute concentration particularly due to the problem of viscosity. As a result, graft polymerization efficiency to polyolefin is reduced and a homopolymer of the radically polymerizable, unsaturated monomer is liable to form. The resulting resin solution has a strong tendency to develop phase separation and usually has a disadvantage that the solution cannot be used as intact for coating.
The present invention provides a novel resin composition which can eliminate conventional problems mentioned above. That is, the resin composition of the invention can be applied to spray coating in a high concentration without developing a separation phenomenon of the resin solution, and can be used for coating, primer and adhesive. The film obtained by using the coating which comprises the resin composition of the invention and a curing agent capable of reacting with active hydrogen and/or a hydroxyl group can exhibit superior weatherability compared to a chlorinated polyolefin film and excellent adhesion properties compared to an untreated polyolefin resin film, sheet or molded article.
DISCLOSURE OF INVENTION
As a result of an intensive examination and investigation in order to achieve the above objects, the present inventors have found that the resin composition obtained by reacting a mixture of polyolefin and a specific (co)polymer, or a reaction mass resulting from polymerization of specific copolymerizable monomers in the presence of polyolefin under radical generation in the presence of in organic solvent, is very effective for achieving the above objects. Thus the invention has been completed.
That is, the present invention can be characterized by the following items (1) to (13).
(1) A resin composition characterized in being obtained by reacting polyolefin (A) with a (co)polymer (B) prepared from a copolymerizable monomer mixture (C) comprising an &agr;,&bgr;-monoethylenically unsaturated monomer and other copolymerizable monomers, in a weight ratio (A)/(B) 1/9-9/1, under radical generation in an organic solvent.
(2) A resin composition characterized in being obtained by polymerizing a copolymerizable monomer mixture (C) comprising an &agr;,&bgr;-monoethylenically unsaturated monomer and other copolymerizable monomers in the presence of polyolefin (A) in a weight ratio (A)/(C) 1/9-9/1 in an organic solvent, and successively by reacting the obtained reaction mass under radical generation.
(3) The resin composition according to item (1), wherein the (co)polymer (B) is modified to have a polymerizable unsaturated bond in the molecule.
(4) The resin composition according to item (3), wherein the modification is carried out by reacting a (co)polymer (B) having hydroxyl group in the molecule with a polymerizable unsaturated carboxylic anhydride.
(5) The resin composition according to anyone of items (1) to (4), wherein the resin composition comprises one or more third components selected from the group consisting of fats and fatty oils, derivatives of the same, epoxy resin and polyester resin.
(6) The resin composition according to item (5), wherein one or more third components have a polymerizable unsaturated bond in the molecule.
(7) The resin composition according to anyone of items (1) to (6), wherein the polymerization reaction under radical generation is carried out in the presence of organic peroxide.
(8) The resin composition according to item (7), wherein the organic peroxide has a tert-butyl and/or benzyl group.
(9) The resin composition characterized by removing the solvent from the resin composition in anyone of the items (1) to (8) and diluting the residue with an optional organic solvent.
(10) A coating characterized by comprising the resin composition according to anyone of items (1) to (9).
(11) A coated film characterized by applying the coating according to item (10).
(12) A coating characterized by consisting of a principal component comprising the resin composition having an active hydrogen atom and/or hydroxyl group according to anyone of items (1) to (9) and a curing agent capable of reacting with an active hydrogen atom and/or hydroxyl group.
(13) A coated film characterized by curing the coating according to item (12).
BEST MODE FOR CARRYING OUT THE INVENTION
One of the resin compositions in the invention can be obtained by reacting polyolefin (A) with the (co)polymer (B) prepared from the copolymerizable monomer mixture (C) comprising an &agr;,&bgr;-monoethylenically unsaturated monomer and other
Asami Keiichi
Kano Taisaku
Machida Koichi
Murakami Tsukasa
Asinovsky Olga
Burns Doane , Swecker, Mathis LLP
Mitsui Chemicals Inc.
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