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
2000-03-22
2003-04-15
Asinovsky, Olga (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...
C525S193000, C525S240000, C525S263000
Reexamination Certificate
active
06548603
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a modified polyolefin resin composition, and more particularly, to a modified polyolefin resin composition containing an unsaturated carboxylic acid-modified polyolefin resin and exhibiting a good adhesion property.
Olefin homopolymers such as polyethylene, polypropylene and poly-1-butene, or copolymers obtained by coplymerizing monomers constituting these homopolymers as main components with other copolymerizable monomers (hereinafter referred to totally as “polyolefin resin”) have been molded into various products and widely used in many applications, because these polymers are relatively inexpensive and excellent in moldability, heat resistance, solvent resistance, mechanical properties, appearance or the like. However, these polyolefin resins are substantially constituted by saturated hydrocarbons and, therefore, exhibit a poor chemical reactivity and a low polarity, thereby causing such a problem that the products made therefrom are poor in adhesion property, coating property, printability or the like. To solve these problems, there have been proposed a method of treating the polyolefin resins with radioactive rays such as electron beam, ozone or the like; and a method of modifying the polyolefin resins by grafting the resins with an ethylenically unsaturated compound such as a vinyl compound, or an unsaturated carboxylic acid or an anhydride thereof (hereinafter referred to totally as “unsaturated carboxylic acid”) in the presence of a radical-generating agent such as an organic peroxide.
The grafting methods have been generally classified into so-called solution methods in which the polyolefin resin is subjected to the graft reaction in a solution state by dissolving the polyolefin resin in a solvent, and so-called melt methods in which the polyolefin resin is subjected to the graft reaction in a molten state using a kneading extruder.
In the solution methods, it is necessary to use a large amount of solvent, resulting in high cost. Further, the solution methods are required to conduct additional treatments such as recovery of the used solvent or the like for environmental protection. Whereas, in the melt methods, the use of such a solvent is not required, so that the melt methods are noticeable as simple and convenient methods.
However, modified polyolefin resins produced by the melt methods contain a considerable amount of residual components such as unreacted compounds (ungrafted ethylenically unsaturated compounds), oligomers (oligomers of ethylenically unsaturated compounds) and other by-products. When these residual components are present in the obtained modified polyolefin resin, there arises such a problem that the adhesion property, coating property and printability thereof are severely damaged.
In order to remove these residual components from the modified polyolefin resin, there have been proposed a method of treating the grafted modified polyolefin resin with a solvent substantially incapable of dissolving the modified polyolefin resin therein and capable of dissolving the polyolefin resin as a raw material and unsaturated carboxylic acid, or under such conditions (“dissolution reprecipitation method”, Japanese Patent Application Laid-Open (KOKAI) No. 54-99193(1979)); a method of producing a modified polypropylene resin by heat-drying the grafted polypropylene resin at a temperature of not less than 60° C. (“heat-drying method”, Japanese Patent Application Laid-Open (KOKAI) No. 56-95914(1981)); a method of producing a modified polyolefin resin by treating the modified polyolefin resin with warm or hot air, or warm or hot water in a temperature range between a Vicat softening temperature of the polyolefin resin as a raw material and a temperature lower by 25° C. than the Vicat softening temperature. (“warm or hot treatment method”, Japanese Patent Application Laid-Open (KOKAI) No. 56-118411(1981)); or the like.
However, in any of these conventional methods, many unimproved problems still remain. That is, in the “dissolution reprecipitation method”, there are caused problems that a considerably large amount of a solvent such as acetone is used, and not only the complicated operations but also the disadvantages are suffered due to the use of the organic solvent as in the above “solution method”. In the “heat-drying method”, the residual components, especially the oligomers of ethylenically unsaturated compounds, cannot be sufficiently removed, and there arises a further problem that the modified polyolefin resin tends to be colored upon the heat-drying. The “warm or hot treatment method” is also insufficient in removal of the residual components, and cannot sufficiently prevent the obtained products from being discolored.
As a result of the present inventors' earnest studies concerning an unsaturated carboxylic acid-modified polyolefin resin obtained by the melt method, which is suitable for imparting a good adhesion property, it has been found that the adhesion property is largely influenced by the graft polymer structure composed of the unsaturated carboxylic acid and polyolefin resin, which is produced upon grafting the polyolefin resin with the unsaturated carboxylic acid. The present invention has been attained on the basis of this finding.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a modified polyolefin resin composition containing an unsaturated carboxylic acid-modified polyolefin resin, which is free from the above-described problems and exhibits a good adhesion property.
In a first aspect of the present invention, there is provided a modified polyolefin resin composition comprising a polyolefin resin modified with an unsaturated carboxylic acid, and satisfying the following formulae (I) and (II) with respect to a small-angle X-ray scattering which is incident perpendicularly on said composition melted at 170° C.:
when a wave number vector (s) is in the range of 0.003 Å
−1
to 0.006 Å
−1
,
−5.0≦
A≦−
3.0 (I)
wherein A represents a gradient of a characteristic curve obtained by plotting logarithms of a corrected scattering intensity (I
1
(s)) on Y (ordinate) axis and the wave number vector (s) on X (abscissa) axis; and said corrected scattering intensity (I
1
(s)) is a value obtained by subtracting a product of an air scattering intensity and an X-ray transmittance and a background intensity based on thermal diffuse scattering, from the small-angle X-ray scattering intensity;
0.001≧
Qn/P≧
0.0001 (II)
wherein Qn and P are values calculated from the following formulae (1) and (2), respectively:
Qn
=
∫
0.003
0.007
s
2
I
1
(
s
)
ⅆ
s
/
∫
0.02
0.04
s
2
I
2
(
s
)
ⅆ
s
(
1
)
wherein s is a wave number vector; I
1
(s) is a corrected scattering intensity; and I
2
(s) is a scattering intensity at 170° C. of polyolefin before modification,
P
=
∫
0.003
0.007
s
2
I
1
(
s
)
ⅆ
s
/
M
(
2
)
wherein M is an average value of s
4
I
1
(s) when s is in the range of 0.003 Å
−1
to 0.004 Å
−1
.
In sub-aspects of the present invention, there are provided an unsaturated carboxylic acid-modified polyolefin resin composition wherein the said unsaturated carboxylic acid is maleic acid or maleic anhydride, and wherein the said polyolefin resin is polypropylene.
In another sub-aspects of the present invention, there are provided an unsaturated carboxylic acid-modified polyolefin resin composition wherein the said polyolefin resin before modification has a melt flow rate of 0.01 to 200 g/10 minute, and wherein the modification of the said polyolefin resin with the said unsaturated carboxylic acid is carried out by melt-kneading said polyolefin and the said unsaturated carboxylic acid in the presence of an organic peroxide.
In an other sub-aspect of the present invention, there is provided an unsaturated carboxylic acid-modified polyolefin resin composition wherein the said polyolefin modified with the
Satou Tsukasa
Shimizu Yuuichi
Yamamoto Satoru
Yano Kazunori
Asinovsky Olga
Conlin David G.
Edwards & Angell LLP
Mitsubishi Chemical Corporation
Roos Richard J.
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