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
2002-08-06
2004-10-05
Acquah, Sam A. (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...
C525S301000, C525S309000, C525S322000, C525S324000, C525S285000
Reexamination Certificate
active
06800688
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a modified polyolefin resin with improved adherence onto the surface of substrate, in particular, surface of substrate having nonpolar thermoplastic resin as a prime material and improved solubility into nonaromatic nonpolar solvent, its composition and uses.
BACKGROUND TECHNOLOGIES
Utilizing the nature to be transformed by heat, the thermoplastic resins are used as various configurations of commodities by molding into not only planar shapes such as sheets and films, but also certain shapes of spherical, cylindrical, box-like, etc. However, since the thermoplastic resins are fundamentally transparent, relatively soft and fragile, printing and painting are provided on their surfaces, for the purpose of improved protection and beautiful ornament.
The thermoplastic resins include resins with polarity and those with nonpolarity. Among nonpolar resins, polyolefinic resins such as polypropylene and polyethylene are adopted widely in recent years, because of low price and many excellent properties such as moldability, chemical resistance, water resistance, electrical characteristics and safety. Different from polar resins such as acrylic resin and polyester resin, however, the polyolefinic resin is nonpolar and crystalline, hence it is difficult to adhere ink, paint or adhesive firmly onto its surface.
In opposition to such substrates of nonpolar resins using polyolefinic resins, as resins with adherence, acid-modified polyolefin resins, from unsaturated carboxylic acid modification down, are proposed. The acid-modified polyolefin resin has adherence onto the nonpolar substrates, but its adherent strength is low and the coated film after drying has tack. For example, when acid-modified polyolefin resin is coated onto the surface of film-shaped substrate and dried to form film and then it is wound up, problems of clinging of dirts onto the surface of film and blocking after winding could not be avoided.
Moreover, the acid-modified polyolefin resin is generally poor in the solubility into solvent and the compatibility with other different types of resins, hence, usable solvents and mixable other resins were restricted on manufacturing paint for painting and printing ink, resulting in problems of difficult production of paint, ink, adhesive or the like with sufficient performance.
Moreover, in recent years, from the viewpoint of environmental problems, such resin that dissolves into solvents containing no aromatic solvent at all has been explored. However, with respect to the solvents to be used for dissolving conventional acid-modified polyolefin, the use of aromatic solvents such as toluene and xylene is essential, hence it was very difficult to dissolve into nonaromatic solvents while maintaining various physical properties such as adherence by the conventional techniques of acid-modified polyolefin.
As the means to improve the problems of solubility into solvent, compatibility with other resins, tack of dried film, and the like, a method of graft copolymerizing two or more unsaturated carboxylic acids or their derivatives with different properties onto polyolefin resin, as using unsaturated carboxylic anhydrides and nonanhydrides such as maleic anhydride and acrylic acid in combination, is disclosed in Japanese Unexamined Patent Publication Nos. Hei 9-40724, Hei 7-82328, Hei 3-227341, Hei 2-245042, etc. Moreover, in addition to the method of simple graft polymerization, a method of modification by further reacting polyester, alcohol, etc., after graft copolymerized unsaturated carboxylic acids or their derivatives such as acrylic acid and maleic anhydride onto polyolefin, is proposed in Japanese Unexamined Patent Publication No. Hei 11-217537. It is reported that the modified polyolefin resin obtainable by this method can improve the solubility into solvent, stability of solution on storing for a long term, etc.
However, when graft copolymerizing monomers of unsaturated carboxylic acids or their anhydrides such as acrylic acid and maleic acid onto polyolefin resin, in particular, polyolefin resin with high propylene content, it is known that the degradation (decrease in molecular weight) is accompanied [Journal of Polymer Science 33, 829 (1995) etc.]. With the modified polyolefin resin obtainable by modifying polyolefin resin with high propylene content by said method, decreased molecular weight was brought about, adherent strength onto nonpolar substrates was still insufficient, and also the problem of tack of formed film could not be solved.
On the other hand, it is also well known that, through the alteration of reaction conditions such as increased use level of said modifying monomer, increased molecular weight of grafting portion can be accomplished easily. In this case, however, the solubility into nonaromatic solvent improved, but sufficient adherent strength onto hard-adherent nonpolar substrates could not still be achieved, because of relative decrease in the content of polyolefin being a major component for developing adherent strength.
Moreover, when graft copolymerizing (meth)acrylic acid or its lower alkyl ester with relatively high polarity, homopolymer and copolymer ungrafting onto polyolefin skeleton were produced in large quantities, resulting in decreased solvent solubility and decreased solvent resistance of dried film etc., which did not come to the practical use.
As described, with the modified polyolefin resins obtained by conventional methods, the enhancement of adherent strength onto nonpolar resins was insufficient. In particular, onto the high-crystalline hard-adherent polyolefin moldings and untreated polyolefin resins without surface treatment for improved adherence such as corona treatment, the adherent strength was insufficient even in the case of reinforced adhesive conditions, hence more improvement in the adherent strength has been desired.
There, the purpose of the invention is to obtain a resin with excellent adherence even onto nonpolar substrates, in particular, hard-adherent nonpolar substrates without preliminary surface treatment for improving hard-adherence or adherence. Furthermore, it is to provide a resin that combines attributes of excellent solubility into nonaromatic solvent, good compatibility with other resins, and improved tack of films obtainable by coating and drying this resin itself or compositions such as paint and ink containing this resin as well.
DISCLOSURE OF THE INVENTION
As a result of diligent investigations, the inventors have found that, by combinationally using unsaturated polycarboxylic acid or its derivative and a particular (meth)acrylic ester as monomers for polyolefin resin and graft copolymerizing to modify, not only said problems are solved with use level of monomers of the order of not injuring the adherent strength, but also excellent adherent strength is exhibited even onto hard-adherent polyolefin moldings and untreated films of polyethylene and polypropylene under broad conditions from condition for adhesive treatment at high temperature to condition for adhesive treatment at low temperature of around room temperature to 100° C. Furthermore, in this case, the inventors have found that the modified resin has excellent solubility into nonaromatic solvent as well as aromatic solvent, leading to the invention.
Namely, the invention relates to
(1) a modified polyolefin resin with polyolefin resin graft modified with unsaturated polycarboxylic acid or its derivative (A) and (meth)acrylic ester (B) represented by a following general formula, with contents of (A) and (B) of 0.1 to 20% by weight and 0.1 to 30% by weight, respectively, in modified polyolefin resin, and with weight average molecular weight of 15,000 to 150,000,
CH
2
═CR
1
COOR
2
(Chemical formula 2)
(wherein R
1
=H or CH
3
, R
2
=C
n
H
2n
+1, n=integer of 8 to 18)
(2) the modified polyolefin resin of (1), wherein said unsaturated polycarboxylic acid or its derivative (A) is itaconic anhydride and/or maleic anhydride,
(3) the modified polyolefin
Fujino Ken-ichi
Fujitaka Terumasa
Matsui Tadashi
Sekiguchi Shunji
Usui Kazuhiro
Acquah Sam A.
Asinovsky Olga
Nippon Paper Industries Co. Ltd.
LandOfFree
Modified polyolefin resin, modified polyolefin resin... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Modified polyolefin resin, modified polyolefin resin..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Modified polyolefin resin, modified polyolefin resin... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3293590