Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-10-04
2004-07-13
Shosho, Callie (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S541000, C524S594000, C524S798000
Reexamination Certificate
active
06762216
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an environmental harmonizing-type printing ink composition containing a vegetable oil as a main component for dissolving a resin for ink, and having a reduced content of a volatile organic solvent.
BACKGROUND OF THE INVENTION
Setting and drying of printing inks are carried out by the permeation of a volatile organic solvent into a base material and the oxidative polymerization of a drying oil or resin having an unsaturated bond contained in the printing ink. The permeation drying and oxidative polymerization drying-type printing inks are required to be set in a short time so that when printed matters are superposed, the ink of the printed surface of the lower printed matter does not attaches to the upper printed matter, and further are required to have a good workability so that after drying by the oxidative polymerization, the formed printed ink layer is not injured even when the printed matter is processed. Accordingly, with regard to the setting property and the drying property on a printed matter, quickness to some extent is necessary.
Hitherto, as the vegetable oil, a linseed oil, a tung oil, a soybean oil, etc., have been used. Conventionally, sufficient setting property and drying speed have been attained by the balance of the oxidative polymerization of these vegetable oils and the permeation of a volatile organic solvent. However, there have become problems that the volatile organic solvents deteriorate the environment of the printing site and further they gives bad influences on the environment of the earth. Accordingly, a printing ink in which the content of a volatile organic solvent is reduced as much as possible has been demanded.
Among conventionally known inks, there has been proposed a printing ink, for printing on a material having a permeability such as paper, which ink uses a soybean oil as a vegetable oil and in which a volatile organic solvent component is also replaced by a vegetable oil. However, a sufficient setting property has not yet been attained. Under such a circumstance, the use of a printing ink has been limited to uses with reduced productivity and workability caused by securing a setting time of the ink as much as possible with a reduced printing speed and by frequently taking out printed matters from a printing machine to prevent a large quantity of the printing matters from being superposed. Thus, inks, which are to be practically used for printing on paper, have been forced to use a volatile organic solvent together with a vegetable oil for attaining a sufficient setting speed.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an environmental-meeting type printing ink composition containing a vegetable oil as a main component for dissolving a resin for ink, and having a reduced content of a volatile organic solvent as much as possible.
Another object of the present invention is to provide a printing ink composition suitable for a paper printing requiring a high-speed setting property.
Other objects and effects of the present invention will become apparent from the following description.
As the result of extensive investigations for solving the above-described problems, the present inventors found that a printing ink composition obtained by dissolving a rosin-modified phenol resin in a vegetable oil solves the problems. The present invention has been completed based on this finding.
That is, the above-described objects of the present invention have been achieved by providing a printing ink composition comprising:
a vegetable oil; and
a rosin-modified phenol resin having a weight average molecular weight of at least 30,000, said rosin-modified phenol resin being dissolved in said vegetable oil,
wherein the printing ink composition has a content of a volatile organic solvent of not more than 3% by weight.
Having the constitution as described above, the present invention makes it possible to provide a printing ink composition suitable for paper printing, which is an environmental-meeting type as having a reduced content of a volatile organic solvent and which has excellent setting property.
DETAILED DESCRIPTION OF THE INVENTION
The printing ink composition contains a rosin-modified phenol resin having a weight average molecular weight of at least 30,000 and a vegetable oil, the rosin-modified phenol resin being dissolved in the vegetable oil, and the content of a volatile organic solvent being not more than 3% by weight. The printing ink composition is suitable for paper printing, which is dried by a permeation drying and oxidative polymerization mechanism, and has excellent setting property.
The term of “setting of ink” means the state that by the permeation of the solvent components in the ink into a permeable base material such as paper, etc., the viscosity of vehicle components is increased to increase the fixing force of the ink onto the paper, and even at the stages before drying with the oxidative polymerization of the vegetable oil having an unsaturated bond, ink is not transferred to the back surface of paper in contact therewith by superposing printed matters.
The high-speed setting property relates to the time required for setting a printing ink printed on a specific paper, and is defined to be the value determined by the following method.
Step 1
On a two-split rubber roller of a test printing apparatus (RI tester) described in the annex 3 of JIS K 5701-1 (5.3.2) is uniformly printed 0.125 cc of a test ink, and the printed ink is transferred onto one of the following blank paper, (1) “OK Kanefuji N Duodecimo/110 kg” manufactured by Oji Paper Co., Ltd., (2) “Tokubishi Art Double Faced Duodecimo/110 kg” manufactured by Mitsubishi Paper Mills Ltd., (3) “OK Kanefuji single faced Duodecimo/110 kg” manufactured by Oji Paper Co., Ltd., and (4) “OK Top Coat N Duodecimo/110 kg” manufactured by Oji Paper Co., Ltd., including the standard blank paper “Japan Paper” of Japan Color of the ISO standard.
Step 2
The ink printed on each paper is measured in terms of the setting property defined by JIS K 5701-1 (6.2.1). The high-speed setting property is defined that the measured setting time should be not longer than 15 minutes.
The printing ink composition of the invention is produced by adding a pigment, an additional vegetable oil, and, if necessary, additives to a varnish for ink prepared by dissolving a rosin-modified phenol resin in a vegetable oil.
As the rosin-modified phenol resin, which is used for the printing ink composition of the invention, various rosin-modified phenol resins each having a weight average molecule weight of at least 30,000 can be used. The preferred weight average molecular weight range is from about 30,000 to 150,000.
The content of the rosin-modified phenol resin in the printing ink composition of the invention is from 20 to 40% by weight. The content thereof is more preferably from 25 to 30% by weight.
As the rosin-modified phenol resin, a petroleum resin-modified rosin-modified phenol resin modified by a petroleum resin can be also used. In the case of modifying with a petroleum resin, the weight ratio of the rosin-modified phenol resin and the petroleum resin is preferably from 95/5 to 85/15. The use of the petroleum resin-modified rosin-modified phenol resin in combination with the rosin-modified phenol resin contributes to an improvement of the gloss of the printed matters, and the proportion of the petroleum resin-modified rosin-modified phenol resin in the whole rosin-modified phenol resins is preferably not higher than 50%.
For the measurement of the weight average molecular weight, the following instruments and conditions apply.
GPC Apparatus: Manufactured by TOSOH CORPORATION (NO.: SC-8020)
Column: SUPER H4000
Solvent: THF
Standard material: Polystyrene
Sample concentration: 0.1 to 0.5%
In the printing ink composition of the invention, a petroleum resin can be used in combination with the rosin-modified phenol resin. The blending amount thereof in the printing ink composition is preferably from 5 to 10% by weight. The petroleum
Fukuda Kouichi
Hori Toshihiko
Ishii Hideo
Matsuki Tomohiro
Shiraishi Takeshi
Armstrong Kratz Quintos Hanson & Brooks, LLP
Dainippon Ink and Chemicals Inc.
Shosho Callie
LandOfFree
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