Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-10-29
2002-12-10
Jagannathan, Vasu (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S497000
Reexamination Certificate
active
06492435
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a water based white color tone pigment ink for a ballpoint pen which can provide drawn lines to be excellent in developing colors such as a white color and a poster color regardless of a color tone of writing paper and which can cover or correct drawn lines printed by means of a writing instrument, a type writer and a copying machine, more specifically to a water based white pigment ink for a ballpoint pen which inhibits titanium oxide from settling even in storing over a long period of time and which has a good follow-up property and makes it possible to write continuously.
BACKGROUND ART
An ink using a compound of silicic acid and aluminum as a dispersant has so far been known as a water based ink using as a colorant titanium oxide, which is a white pigment. Further, described in Japanese Patent Laid-Open No. Hei 7-62281 is a water based white pigment composition containing at least titanium oxide having an oil absorption of 30 or more and an isoelectric point of pH 7 or less, a water soluble (meth)acryl base resin and water, which is used for a correction fluid and an ink for a writing instrument.
However, since these inks do not inhibit titanium oxide from settling, they have to be stirred again before use and have had the inconvenience that a ball for stirring has to be put in a tank for storing ink.
In contrast with the inks described above, as a water based white color pigment ink for a ballpoint pen in which titanium oxide does not settle, an ink containing a white pigment, tabular silicate, a water soluble resin, a water soluble organic solvent and water and having a viscosity of 6000 to 100,000 mPa·s is described in, for example, Japanese Patent Laid-Open No. Hei 6-287499. However, this ink has the problem that it has a high viscosity and is inferior in a follow-up property in writing.
Further, described in Japanese Patent Laid-Open No. Hei 7-216283 is an ink containing a white pigment, a nonionic surfactant having an HLB of 17.0 or more, a water soluble resin and water and having a viscosity of 6,000 to 50,000 mPa·s. However, this ink also does not solve the problem that the follow-up property in writing is not good because of the high viscosity.
Further, described in Japanese Patent Laid-Open No. Hei 8-12916 is an ink containing titanium oxide, a thickening water-soluble resin, a binder, sugar alcohol and water and having a viscosity of 6,000 to 50,000 mPa·s and a viscosity index of 2 or more which is obtained from a revolution difference of a viscometer. However, even if this viscosity index is met, the inferior follow-up property of the ink in writing quickly and splitting of the drawn lines are not solved. In addition thereto, since only a white pigment is added as a coloring material, the ink has the problem that the marking performance is inferior on writing paper having a white ground.
On the other hand, described in Japanese Patent Laid-Open No. Hei 4-258677 is a water based ink for a marking pen or for correction which contains hollow particles having two or more pores in the inside thereof in place of titanium oxide in order to avoid coagulating and settling of titanium oxide and can display a covering effect.
However, the hollow particles used in this water based ink have a covering effect but have the problem that the covering effect is still lower than that of titanium oxide and that when the adding amount of the hollow particles is increased, inferior dispersion thereof is caused.
In light of the conventional technical problems described above, an object of the present invention is to solve them and to provide a water based white color tone pigment ink for a ballpoint pen which is improved in water resistance and weatherability of drawn lines by enhancing dispersibility of titanium oxide that is an excellent white covering agent and can provide vivid drawn lines having a good poster color tone even on writing paper having a dark color, which is inhibited from deterioration such as coagulation and settling/separation of titanium oxide particles even in storing over a long period of time and which has a good follow-up property and makes it possible to write continuously.
DISCLOSURE OF THE INVENTION
Intensive investigations repeated by the present inventors regarding the conventional technical problems described above have resulted in successfully obtaining a water based white color tone pigment ink for a ballpoint pen which meets the object described above by adding titanium oxide having specific physical properties and specific ink components, and thus coming to complete the present invention.
That is, the water based white color tone pigment ink for a ballpoint pen according to the present invention comprises the following items (1) to (4):
(1) A water based white color tone pigment ink for a ballpoint pen comprising titanium oxide having an oil absorption of 25 (g/100 g) or less and an average particle diameter of 400 nm or less, a water soluble resin, a thickener, water and a polar solvent.
(2) The water based white color tone pigment ink for a ballpoint pen as described in the above item (1), containing at least one complementary colorant selected from a pigment, a resin emulsion, a hollow resin emulsion and a pseudo pigment obtained by dyeing these resin emulsions.
(3) The water based white color tone pigment ink for a ballpoint pen as described in the above item (1) or (2), wherein the ink has a viscosity of 500 to 5000 mPa·s.
(4) The water based white color tone pigment ink for a ballpoint pen as described in any of the above items (1) to (3), wherein the water soluble resin comprises a polymer and/or a copolymer of at least one monomer selected from acrylic acid, methacrylic acid, maleic acid, styrene, acrylic ester and methacrylic ester.
BEST MODE FOR CARRYING OUT THE INVENTION
The embodiment of the present invention shall be explained below in detail.
The water based white color tone pigment ink for a ballpoint pen according to the present invention is characterized by comprising titanium oxide having an oil absorption of 25 (g/100 g) or less and an average particle diameter of 400 nm or less, a water soluble resin, a thickener, water and a polar solvent.
Titanium oxide used in the present invention is used as a white pigment for providing the drawn lines with a covering property.
Uniformly and finely dispersed particles of titanium oxide make it possible to improve a covering property, a white color property, water resistance and light fastness of the drawn lines and an aging stability of the ink itself. The dispersibility of titanium oxide particles is affected largely by a treating condition of the surface of the particles, and inorganic adsorbing treatment with silica or alumina and organic coating treatment are usually carried out for easier treatment for enhancing the dispersibility.
The condition of the particle surface made by this treatment exerts a large influence on the oil absorption. For example, when a silica or alumina-adsorbed coating layer grows large to form a porous layer, the large oil absorption value is exhibited. When the oil absorption value is large, the particles coagulate each other due to adsorption and degradation of the dispersibility caused by releasing the coating layer are brought about. Accordingly, such treatment is not suitable for maintaining the dispersibility over a long period of time.
If titanium oxide particles are finely crushed to primary particles and the primary particles have a small particle diameter, they are less liable to settle down. However, if the particles themselves are smaller than the wavelength of visible rays, the covering power is reduced, and the capacity as a white pigment is lowered.
In the present invention, in relation to the preceding dispersibility and covering power of titanium oxide, the surface condition of the particles and the particle diameter have been investigated in further details, and as a result, it has been confirmed that use of titanium oxide having such physical properties as an oil absorption of 25 (g/100 g) or
Kamagata Tadashi
Miyamoto Masaru
Shinozuka Miki
Darby & Darby
Jagannathan Vasu
Mitsubishi Pencil Kabushiki Kaisha
Shosho Callie E
LandOfFree
Water based white color tone pigment ink for ball point pen does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Water based white color tone pigment ink for ball point pen, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water based white color tone pigment ink for ball point pen will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2992282