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
2000-09-08
2003-04-29
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...
C525S111000, C525S292000, C525S301000
Reexamination Certificate
active
06555621
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a binder resin composition to be used when painting onto polyolefinic moldings and a method for producing the same.
Because of many advantages such as light weight, antirust and broad degree of freedom for design, in recent years, plastics are used broadly as the materials of automotive parts, electrical parts, building materials, 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 in broad range as industrial materials and the growth of demand thereof is also expected in future. Different from synthetic resins with polarity, however, polyolefinic resin is nonpolar and crystalline, hence it has also drawbacks of difficult painting and adhesion therewith.
For treating before painting and adhesion, a method of activating the surface of molded products by plasma treatment or gas flame treatment, or a method of coating a primer (undercoating agent) having chlorinated polyolefin as a major component is adopted.
For the painting of automotive bumpers with polypropylene, for example, in Japanese Unexamined Patent Publication No. Sho 57-36128 and Japanese Patent,Publication No. Sho 63-36624, primer compositions having chlorinated modified polyolefin as a major component are disclosed.
Although these primers comprising chlorinated products are excellent in the conventional adherence to polyolefin, recently, prime materials with insufficient adherence of primer have also appeared with high rigidification of prime materials, hence conventional chlorinated polyolefinic resins cannot correspond sufficiently as primers.
As described above, it is the status quo that, with conventional chlorinated polyolefinic resins or their derivatives, strong adhesiveness has not been obtained to some prime materials.
Said primer compositions and the like proposed so far were those having chlorinated isotactic polypropylene obtained by chlorinating isotactic polypropylene (IPP) produced using Ziegler-Natta catalyst as a polymerization catalyst, as a major component. In recent years, metallocene compounds have been developed as polymerization catalysts of polyolefin and, in Japanese Unexamined Patent Publication Nos. Hei 7-138325 and Hei 7-149975, etc., polymerization examples of syndiotactic polypropylene (SPP) produced using metallocene compound as a polymerization catalyst are disclosed. This SPP has features such as narrower molecular weight distribution, more potential of arbitrary control of molecular weight and lower melting point and glass transition point than those of IPP, and additionally, it is excellent in the transparency when converted to resin moldings, thus making it as a resin that more development can be expected hereafter.
As one utilizing method of SPP, in Japanese Unexamined Patent Publication No. Hei 7-18016, examples of adhesives that use chlorinated products of syndiotactic polypropylene are disclosed. However, because these adhesives are simply using the chlorinated products of syndiotactic polypropylene, when using as primers at the time of painting onto PP moldings, they have a drawback of no adherence to upper paint.
The purpose of the invention is to provide a binder resin composition with excellent solvent solubility, with excellent adherence to polypropylenic prime materials, and also with excellent adherence to upper paint.
SUMMARY OF THE INVENTION
The inventors have solved the problems aforementioned with a binder resin composition characterized by comprising carboxyl group-containing chlorinated syndiotactic polyolefin resin with chlorine content of 0.1 to 40 wt. %, grafting level of &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride of 0.5 to 10 wt. % and weight average molecular weight of 30000 to 220000 and organic solvent.
DETAILED DESCRIPTION OF THE INVENTION
The polyolefin resin being raw material of the invention is a syndiotactic polyolefin produced by using metallocene catalyst as a polymerization catalyst. It is possible to use syndiotactic polypropylene (SPP), propylene-&agr;-olefin copolymer produced by using metallocene catalyst as a polymerization catalyst, or the like solely or by mixing two or more kinds.
The &agr;-olefin component to be used in the propylene-&agr;-olefin copolymer is preferable to be at least one kind of &agr;-olefin with number of carbon atoms of 2 or 4 to 6 selected from, for example, ethylene, 1-butene, 1-pentene, 4-methyl-1-petene, 3-methyl-1-petene and 1-hexene. The ratio of propylene component to a-olefin component in the copolymer is not particularly restricted, but the propylene component is desirable to be not less than 50 mol %.
The metallocene catalyst to be used here is a catalyst with metallocene compound of Group IV transition metal combined with methylaluminoxane obtainable by hydrolyzing trimethylaluminum, and, upon polymerization of olefin, it has such features that the molecular weight distribution is narrower, random copolymerizability is more excellent resulting in narrower composition distribution and wider range of copolymerizable comonomers, compared with conventional Ziegler-Natta catalyst.
The syndiotactic polyolefin resin to be used in the binder resin composition of the invention can be produced by the publicly known method using metallocene catalyst. As a concrete resin, Tiallo (trade name of syndiotactic polypropylene from,Mitsui Chemicals Inc.) can be used.
The binder resin composition of the invention can be obtained by introducing &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride and chlorine to said syndiotactic polyolefin resin, and the production thereof is possible by two methods mentioned below. Namely, they are a method (first method) of graft polymerizing &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride beforehand onto syndiotactic polyolefin-resin and then conducting chlorination reaction, and a method (second method) of conducting chlorination reaction and then graft polymerizing &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride.
In following, the concrete producing methods will be exemplified. In the first method, graft copolymerizing &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride first onto syndiotactic polyolefin resin can be performed by the publicly known methods; a method (melt method) of melting said resin by heating over melting point in the presence of radical generator and reacting with &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride, a method (solution method) of dissolving said resin into organic solvent and then reacting with &agr;,&bgr;-unsaturated carboxylic acid and/or its acid anhydride by heating under stirring in the presence of radical generator, and the like.
In the case of melt method, there is an advantage of simple procedure, because of reacting for short time at a temperature of over melting point and under 400° C. using Banbury mixer, kneader, extruder, etc.
While, in the case of solution method, it is desirable to use aromatic solvents such as toluene and xylene, but, besides, it may also be safe to use ester type solvent, ketone type solvent, etc. by mixing partially. The radical generator to be used for the reaction can be selected appropriately from publicly known ones, but, particularly, organic peroxide type compounds are desirable.
As said organic peroxide.type compounds, for example, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dilauryl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, cyclohexanone peroxide, t-butylperoxy benzoate, t-butylperoxy isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy isopropylcarbonate, cumylperoxy octoate, etc. are mentioned.
In the case of solution method, however, because it is required to replace said solvent with chlorinating solvent such as chlor
Ueda Takaaki
Urata Keiji
Mullis Jeffrey
Nippon Paper Industries Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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