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
2000-03-17
2002-10-08
Woodward, Ana (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...
C525S183000
Reexamination Certificate
active
06462130
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a novel chlorine-free modified polyolefin with excellent adherence to nonpolar sheets, films and moldings such as polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer and ethylene-vinyl acetate, with no tack, and also with excellent cohesion.
Because of low price and many excellent properties such as moldability, chemical resistance, water resistance and electrical characteristics, polyolefin such as polypropylene and polyethylene are used widely in recent years as sheets, films and moldings, etc. Different from polar substrates such as polyurethane resin, polyamide resin, acrylic resin and polyester resin, however, polyolefinic substrates are nonpolar and crystalline, leading to drawbacks of difficult paintability and adhesion.
So far, modified polyolefins obtainable by modifying polyolefins with unsaturated carboxylic acid and/or acid anhydride and further acid-modified chlorinated polyolefins obtainable by chlorinating them have been used as paint additives, primers and adhesives, because of excellent adherence to said nonpolar substrates. However, conventional acid-modified polyolefins represented by maleic anhydride-modified polyolefins have drawbacks of poorer adherence to nonpolar substrates, more liability to cause cohesive failure, stranger tackiness, etc. compared with chlorination type modified polyolefins. Moreover, chlorinated polyolefins with excellent adherence also have drawbacks of poor weather resistance etc. and, in addition, from recent upsurge of environmental problems, their uses have also become to be restricted. Based on such background, the development of novel chlorine-free resin with adherence to nonpolar substrates equal to or more than that of chlorinated polyolefin and with excellent physical properties such as tackiness and cohesion has been expected.
On the other hand, with regard to combinations of modified polyolefin with polyamide, there are reports for the purposes of improved physical properties such as thermal creep resistance and shock resistance of moldings in for example, Japanese Unexamined Patent Publication Nos. Hei 4-122736, Hei 9-310014 and Hei 10-287749. In Polymer, 37 (7), 1129 (1996), etc., the compatibility of polyolefin·polyamide type alloys is reported. Moreover, Japanese Unexamined Patent Publication No. Hei 5-279431 reports that, by reacting polyamide with unreacted unsaturated acid and/or acid anhydride in acid-modified polyolefin, the offensive odor and skin irritability were improved.
However, in the application fields of rein featured by having excellent adherence to nonpolar substrates, where chlorinated polyolefins are used traditionally, there are no reports that found novel uses and features by combining modified polyolefin with polyamide.
The purpose of the invention lies in providing a novel chlorine-free modified polyolefin with excellent adherence to polyolefinic resin moldings, with no tack, and also with excellent cohesion. As a result of diligent investigations for solving this subject, the inventors have found that the excellent adherence to nonpolar substrates, the elimination of tack, the enhancement of cohesion and so on can be achieved at the same time by melting with kneading to react the modified polyolefin, which can be obtained by using an unsaturated carboxylic acid anhydride as an essential ingredient, with a particular polyamide, leading to the invention based on this knowledge.
SUMMARY OF THE INVENTION
As described, according to the invention, following (1) through (6) are provided.
(1) A polyamide-modified polyolefin composition obtainable by heating to react (A) modified polyolefin with weight average molecular weight of not less than 5,000 to not more than 150,000, graft modified so as the content of unsaturated carboxylic acid anhydride to become not less than 0.1 wt. % to not more than 20 wt. % based on raw material polyolefin, and (B) polyamide with number average molecular weight of not less than 3,000 to not more than 30,000 represented by formula [1], so as the weight ratio of (A) to (B) to become 400:1 to 1:2.
H—(NH—C
n
H
2n
—CO)
m
—OH [1]
(wherein n denotes an integer not less than 6 to not more than 13, and m denotes polymerization degree).
(2) A polyamide-modified polyolefin composition obtainable by heating to react (A) modified polyolefin with weight average molecular weight of not less than 5,000 to not more than 150,000, graft modified so as the content of unsaturated carboxylic acid anhydride to become not less than 0.1 wt. % to not more than 20 wt. % based on raw material polyolefin and the content of ethylenic unsaturated monomer to become not less than 0.01 wt. % to not more than 900 wt. % base on raw material polyolefin, and (B) polyamide with number average molecular weight of not less than 3,000 to not more than 30,000 represented by said formula [1], so as the weight ratio of (A) to (B) to become 400:1 to 1:2.
(3) An adhesive for nonpolar substrates using the polyamide-modified polyolefin composition of (1) or (2).
(4) A primer for nonpolar substrates using the polyamide-modified polyolefin composition of (1) or (2).
(5) A paint binder using the polyamide-modified polyolefin composition of (1) or (2).
(6) An ink binder using the polyamide-modified polyolefin composition of (1) or (2).
DETAILED DESCRIPTION OF THE INVENTION
The polyolefins to become the raw materials of modified polyolefin to be used in the invention are homo- or co-polymers of &agr;-olefin with number of carbon atoms of 2 to 20, preferably 2 to 6, such as ethylene, propylene, butene-1, pentane-1, hexene-1, heptene-1, octene-1 and 4-methyl-1-pentene, chain or cyclic polyenes such as cyclopentene, cyclohexene, 1,4-hexadiene, 1,5-hexadiene, divinylbenzene, 1,3-cyclopentadiene, 1,3-cyclohexadiene and 5-vinyl-2-norbornene, styrene, substituted styrene, etc.
Moreover, the nonpolar substrates referred to so in the invention point to nonpolar sheets, films or moldings of polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, etc. Also, they include surface-treated ones of these substrates with plasma, corona or the like.
The proportion of said olefin monomer in the polyolefin that becomes the raw material of modified polyolefin can be selected arbitrarily, but, for the inventive polyamide-modified polyolefin to have the adherence to propylene substrate among nonpolar substrates, the proportion of propylene is preferable to be 50 to 98%. If under 50%, then the adherence to propylene substrate is poor, and, if over 98%, the flexibility is insufficient.
The usable molecular weight of polyolefin can be selected freely so as the weight average molecular weight of modified polyolefin to become 5,000 to 150,000, but, even a polyolefin with weight average molecular weight of over 150,000 becomes usable by the publicly known methods for adjusting the molecular weight to said suitable range by degrading in the presence of heat or radical, and the like.
As the unsaturated carboxylic acid anhydrides to be used in the invention, anhydrides of maleic acid, itaconic acid, citraconic acid, aconitic acid, etc. are mentioned. These anhydrides can be used solely or in combination, but the use of maleic anhydride is preferable. The use level of unsaturated carboxylic acid anhydride is preferable to make so as the content in modified polyolefin to become 0.1 to 20 wt. %, preferably 0.3 to 15 wt. % based on polyolefin. If the content is under this range, then decreased adherence to nonpolar substrates, aggravated solubility and decreased reactivity with polyamide result and inversely, if too much, decreased adherence and more generation of unreacted unsaturated carboxylic acid anhydride result, which is unpreferable.
In the invention, ethylenic unsaturated monomer can be used simultaneously with unsaturated carboxylic acid anhydride. Moreover, it is also possible to react modified polyolefin, in which the raw material pol
Fujino Ken-ichi
Fujitaka Terumasa
Mitsui Hideaki
Usui Kazuhiro
Yoshioka Hidetoshi
Nippon Paper Industries Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Woodward Ana
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