Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-10-11
2002-09-10
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S090000, C524S413000
Reexamination Certificate
active
06448312
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a colored resin composition for water pipes and a colored water pipe (including joints for water pipes, similarly hereinafter). More particularly, the present invention relates to a colored resin composition for water pipes which is colored in a bluish color, exhibits an excellent fastness of color tone of the coloring component to water containing chlorine and an excellent property for preventing formation of blisters in water containing chlorine, has a color tone within a specific color solid expressed by the values of a Munsell standard color table and shows an excellent hiding property, and a colored water pipe having the above properties of the color tone.
BACKGROUND ART
As major pigments for coloring water pipes to bluish colors, organic pigments such as phthalocyanine blue pigments or indanthrene blue pigments, or inorganic pigments such as ultramarine blue pigments or cobalt blue pigments are used.
When a commercially available copper phthalocyanine blue pigment having no chlorine atoms or one chlorine atom is used singly for this application, the copper phthalocyanine blue pigment is decomposed by the oxidizing action of chlorine water and rapid discoloration takes place in the test of resistance to chlorine water. Blisters are occasionally formed on the surface of a test plate when some types of the copper phthalocyanine pigments are used.
It is reported in Japanese Patent Application Laid-Open No. Heisei 7(1995)-76639 that a phthalocyanine blue pigment having copper, zinc, nickel, iron or hydrogen as the central atom and 2 to 10 chlorine atoms introduced therein provides a colored resin composition having an excellent resistance to discoloration with water containing chlorine. However, in the test of resistance to chlorine water using a colored resin composition containing the above phthalocyanine blue pigment, a problem arises in that the above test plate shows formation of blisters on the surface in a shorter time than test plates containing conventional copper phthalocyanine blue pigments do. Moreover, the color tone is not within the color solid composed of the hue in the range of 10 B to 10 PB, the lightness in the range of 2 to 6 and the chroma in the range of 4 to 14 each expressed by the values of the Munsell standard color table.
When it is considered that the discoloration and the formation of blisters take place in the test of resistance to chlorine water in the use of any types of phthalocyanine blue pigments, it should be avoided that the phthalocyanine blue pigment alone is used in the present application although the phthalocyanine blue pigments have a great coloring ability and provide a great economic advantage.
Indanthrene blue pigments have a coloring ability as excellent as that of the phthalocyanine blue pigments. However, in the test of resistance to chlorine water of a resin composition containing an indanthrene blue pigment in an amount of 0.05% by weight or more of the resin component, unfavorable phenomena arise in that blisters are formed and the color tone changes into dark green. Therefore, the use of indanthrene blue pigments should be avoided.
When a colored resin composition containing an ultramarine blue pigment is used, it is inevitable that marked discoloration takes place in the test of resistance to chlorine water since the ultramarine blue pigment is vulnerable to acids. Therefore, it is preferable that an ultramarine blue pigment is not used for water pipes for water sterilized with chlorine. Moreover, since the ultramarine blue pigments have smaller coloring ability than those of phthalocyanine blue pigments and indanthrene blue pigments, a combined use of the ultramarine blue pigments with other pigments is not advantageous.
Cobalt blue pigments exhibit less discoloration in the test of resistance to chlorine water and form no blisters when the used amount is 2.0% by weight or less. However, since the cobalt blue pigment has an inferior coloring ability, the cobalt blue pigment must be used in a greater amount for obtaining suitable color tone and color concentration when the cobalt blue pigment is used alone and blisters tend to be formed in the test of resistance to chlorine water. Moreover, economic disadvantage arises. Therefore, it is difficult that the cobalt blue pigment is used alone.
When the cobalt blue pigment is used as the main pigment and the color tone is brought within the color solid composed of the hue in the range of 10 B to 10 PB, the lightness in the range of 2 to 6 and the chroma in the range of 4 to 14 each expressed by the values of the Munsell standard color table, the addition of a reddish pigment is essential. However, reddish pigments other than dioxazine pigments have drawbacks. When a quinacridone pigments is added, dark dim color tone is obtained. When an azo pigment or a perylene pigment is added, the color becomes red after the test of resistance to chlorine water due to excessively excellent resistance to chlorine water and unpleasant impression is obtained.
Under the above circumstances, the present invention has an object of providing a colored resin composition for water pipes which is colored in a bluish color, has a color tone within the color solid composed of the hue in the range of 10 B to 10 PB, the lightness in the range of 2 to 6 and the chroma in the range of 4 to 14 each expressed by the values of the Munsell standard color table, exhibits an excellent hiding property, excellent fastness of the color tone of the coloring component to chlorine water and an excellent property for preventing formation of blisters in chlorine water, has a color tone within the above specific color solid expressed by the values of the Munsell standard color table even after the test of resistance to chlorine water and is economically advantageous, and a colored water pipe having the above properties of the color tone.
DISCLOSURE OF THE INVENTION
As the result of extensive studies by the present inventors to develop the colored resin composition for water pipes which is colored in a bluish color, has an excellent hiding property and exhibits the above properties of color tone, it was found that the object can be achieved with a colored resin composition which is a combination of a polyethylene resin and specific pigments in specific relative amounts. The present invention has been completed based on the knowledge.
The present invention provides:
(1) A colored resin composition for water pipes which comprises (A) a polyethylene resin and, per 100 parts by weight of the polyethylene resin, (B) 0.01 to 2.0 parts by weight of (i) a cobalt blue pigment, 0.0001 to 0.2 parts by weight of (ii) at least one pigment selected from phthalocyanine pigments having no metals and metal phthalocyanine pigments having no chlorine atoms or one chlorine atom in a molecule, 0.0001 to 0.2 parts by weight of (iii) a dioxazine pigment and 0.002 to 0.5 parts by weight of (iv) a titanium dioxide pigment;
(2) A colored resin composition for water pipes described in (1), wherein a color tone is within a color solid composed of a hue in a range of 10 B to 10 PB, a lightness in a range of 2 to 6 and a chroma in a range of 4 to 14 each expressed by values of a Munsell standard color table;
(3) A colored resin composition for water pipes described in any one of (1) and (2), wherein a color tone is within a color solid composed of a hue in a range of 10 B to 10 PB, a lightness in a range of 2 to 6 and a chroma in a range of 4 to 14 each expressed by values of a Munsell standard color table after a test of resistance to chlorine water in accordance with a method of Japanese Industrial Standard K 6762 for 500 hours;
(4) A colored resin composition for water pipes described in any one of (1), (2) and (3), wherein the dioxazine pigment of component (iii) of component (B) is at least one compound selected from compounds expressed by formula [1] and formula [2]:
and
(5) A colored water pipe which comprises a colored polyethylene resin composition and has a color tone wit
Matsuoka Tohru
Nagai Yozo
Nakamura Mitsuo
Oshima Kotaro
Frishauf Holtz Goodman & Chick P.C.
High Tech Chem Co., Ltd.
Sanders Kriellion A.
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