JP2006028388A - Oil-based ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil-based ink which has good color developability, can have a freely selected hue, is stable even after the lapse of time, can be quickly absorbed by gloss papers such as coated paper and art paper without bleeding and strike-through, can give a stamp pad, a vermilion inkpad, or a self-inking rubber stamp which, even when left without being closed with its cover, does not suffer from pad face drying or inkpad face drying and shows good ink delivery, and can be readily poured into an ink sorbent. <P>SOLUTION: The oil-based ink is one prepared by formulating a polyoxyethylene polyoxypropylene monoalkyl ether as the principal solvent, propylene glycol as a bleed inhibitor, and a dye as a colorant and used in a stamp pad, a vermillion inkpad, or a self-inking rubber stamp and characterized by having adjusted viscosity of 500 to below 1,000 mPas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dye-based stamp base or vermilion or oil-based ink for penetrating printing, which is intended for imprinting paper that absorbs ink (hereinafter collectively referred to as “absorbing paper”), and in particular, is glossy. The present invention relates to a dye-based stamp base or vermilion or oil-based ink for penetrating printing, which is a target to be stamped on paper (hereinafter collectively referred to as “glossy paper”) such as coated paper and art paper that are difficult to absorb ink.

Conventionally used oils for stamp stands, vermilion oils and penetrating oils can be broadly classified into those using pigments and those using dyes as colorants. The former is excellent in light resistance due to the properties of the pigment, but generally has poor color developability and has the disadvantage that the pigment settles or aggregates. On the other hand, the latter is generally good in color developability and has the advantage of not causing problems such as sedimentation because it is completely dissolved in a solvent.
In addition, as other ink classification methods, the solvent can be roughly classified into an aqueous solvent and an oil solvent. In the case of water-based ones, mainly high-quality paper is used as the object to be imprinted, and the ink is colored by being absorbed and dried. In addition, due to the characteristics of the solvent, it has excellent properties that the stamp stand and vermilion board surface do not dry, and the penetrating stamp surface does not dry. However, for glossy paper such as coated paper whose surface is coated with titanium oxide or the like, the ink absorption is extremely slow, not only dirtying fingers but also other documents, making it virtually impossible to use. On the other hand, oily substances can be further classified into those of volatile organic solvents and those of nonvolatile organic solvents. The oil-based ink composed of a volatile organic solvent volatilizes immediately after imprinting, and the colorant is fixed by the resin. However, for absorbent papers such as coated paper and fine paper, the penetrating power is excessive, bleeding and show-through are remarkable, and the paper cannot be used very much. Furthermore, if the stamp stand, vermilion, and the penetrating seal lid are left open, or if the sealing is not complete, the board surface and the stamped surface dries in a short time, often making imprinting impossible. In such a case, the user had to drop the solvent and redissolve and use the dye or resin, which was inconvenient. On the other hand, oil-based inks composed of non-volatile organic solvents have excellent properties that there is almost no bleeding or show-through and the board surface does not dry, but in glossy paper such as coated paper, art paper, etc. whose surface is coated with titanium oxide, Absorption of ink was extremely slow, not only dirtying fingers but also other documents, making it virtually impossible to use.

  Further, as a stamping ink that is less likely to be biased even after long-term storage, suppresses the occurrence of blurring or blurring on the print marks, and at the same time suppresses the blurring of the print marks, thereby obtaining a clear print image. -219159, JP-A-11-071542 and JP-A-11-106691 are disclosed. However, these oil-based inks have been set with a high viscosity by blending a resin, or have been set with a high viscosity by imparting plasticity or thixotropic so-called gel properties. However, the ink absorption was extremely slow, not only dirtying fingers but also other documents, making it virtually impossible to use. Further, since the fluidity is designed to be a non-Newtonian fluid, there is a drawback that the ink is difficult to move, ink ejection is poor, and the ink is difficult to inject into the ink occlusion body.

JP-A-10-219159 JP 11-071542 A Japanese Patent Laid-Open No. 11-106691

  Therefore, it has good color development, can be freely selected in color, is stable over time, and is quickly absorbed without causing bleeding or show-through in coated paper or art paper. There is a need for the development of oil-based inks that allow the ink and ink to be easily injected into the ink occlusion body, even if the cover of the ink and vermillion or penetrating mark is left open.

  In order to solve the above-mentioned problems, a stamp base or vermilion or oil-based ink for penetrating stamps comprising polyoxyethylene polyoxypropylene monoalkyl ether as a main solvent, propylene glycol as a bleeding inhibitor, and a dye as a colorant A stamp base or vermilion or penetrating oil-based ink having a viscosity adjusted to 500 mPa · s or more and less than 1000 mPa · s. Furthermore, the stamp stand or vermilion or penetrating oil-based ink containing polypropylene glycol having a molecular weight of 200 to 800 as a secondary solvent is provided.

As a result of earnest research, the inventor of the present application finds a dye-based stamp stand or vermilion or penetrating oil-based ink that solves the above problems by adjusting the ink to a specific viscosity using a specific solvent and colorant. succeeded in.
In other words, the oil-based ink of the present invention has good color developability, can freely select the hue, is stable over time, and does not cause bleeding or show-through on glossy paper such as coated paper or art paper. In addition, even if the stamp stand, vermilion, and the penetrating mark lid are left open, the board surface and printed surface do not dry, the ink discharge is good, and the ink can be easily injected into the ink occlusion body. is there. In addition, the oil-based ink of the present invention exhibits excellent characteristics that do not cause bleeding or show-through even on PPC recycled paper and high-quality paper.
Further, since the oil-based ink of the present invention is a Newtonian fluid having almost no gel property, there is an advantage that the ink flow is smooth, the ink discharge is good, and the ink can be easily injected into the ink occlusion body. .

Hereinafter, the present invention will be described in detail.
The oil-based ink of the present invention is an oil-based ink used for stamp stands, vermilion and penetrating marks, and is composed of polyoxyethylene polyoxypropylene monoalkyl ether as a main solvent, propylene glycol as a bleeding inhibitor, and a dye as a colorant. It is an essential constituent requirement to adjust the viscosity to 500 mPa · s or more and less than 1000 mPa · s. Further, since the oil-based ink of the present invention is a Newtonian fluid having almost no gel property, the viscosity may be adjusted to 500 mPa · s or more and less than 1000 mPa · s at room temperature, and in particular, the viscosity is between 20 ° C. and 30 ° C. Is preferably adjusted to 500 mPa · s or more and less than 1000 mPa · s.

The solvent used as the main solvent in the oil-based ink of the present invention is polyoxyethylene polyoxypropylene monoalkyl ether, which is a catalyst of ethylene oxide and propylene oxide in a ratio of ethylene oxide: propylene oxide = 1 to 10: 1-10. One of the terminal hydrogens of polyoxyethylene polyoxypropylene, which is one of a random copolymer, an alternating copolymer, and a block copolymer obtained by ring-opening polymerization below, is methyl group, ethyl group, n-propyl group, an isopropyl group, n- butyl group, an isobutyl group, refers to a polymeric compound substituted with an alkyl group such as sec- _{propyl, R-O- (C 2 H} 4 O) m - (C 3 H 6 O) _It has a chemical formula of _n- H (R: alkyl group). Specifically, polyoxyethylene polyoxypropylene monoethyl ether, polyoxyethylene polyoxypropylene mono n-butyl ether, polyoxyethylene polyoxypropylene monoisobutyl ether and the like can be mentioned, and the degree of polymerization is 30 to 100 (m And n = 30 to 100) are preferably used. In the present invention, the above-mentioned solvents can be used alone or in combination of two or more so that the oil-based ink of the present invention has a specific viscosity, and the blending ratio is 40 to 90% by weight, preferably 45 to 45% in the ink composition. 80% by weight.

  The solvent used as a bleeding inhibitor in the oil-based ink of the present invention is propylene glycol. When oil-based inks containing the polyoxyethylene polyoxypropylene monoalkyl ether as a main solvent are used and stamped on glossy paper such as coated paper and art paper, PPC recycled paper and fine paper, the ink spreads in the paper and characters However, it was found that the ink blended with the propylene glycol stays in the stamped portion, and as a result, bleeding can be prevented. In the present invention, propylene glycol is 20 to 50% by weight, preferably 25 to 40% by weight in the ink composition. If it is less than 20% by weight, bleeding cannot be effectively prevented, and if it exceeds 50% by weight, the viscosity becomes too low, and it is not suitable as a stamp base or vermilion or penetrating oil ink.

  As the colorant used in the oil-based ink of the present invention, known direct dyes, acid dyes, basic dyes, disperse dyes and oil-soluble dyes that are soluble in the above-mentioned solvents can be used. Oil-soluble dyes such as disazo, metal complex monoazo, anthraquinone, phthalocyanine, triallylmethane and the like can be used. A salt-forming oil-soluble dye can also be used. Salt-forming oil-soluble dyes are dyes in which hydrophilic groups such as acid dyes, direct dyes, basic dyes, etc. are substituted with hydrophobic groups. The hydrophilic groups of acid dyes are cationic activators, resin bases, amines, basic dyes. Substituted with a hydrophobic group such as a direct dye hydrophilic group with a hydrophobic group such as a cationic activator, resin base, amine, basic dye, etc., a basic dye hydrophilic group with an anionic activator resin acid, Those substituted with hydrophobic groups such as acid dyes and direct dyes can be used. Specifically, C.I. I. Solvent Yellow 16, 19, 19, 21, 34, 56, 82, C.I. I. Solvent Orange 2, 5 and 14, C.I. I. Solvent Red 1, 3, 8, 18, 24, 49, 82, 100, 124, 132, C.I. I. Solvent Violet 8, 21 and 27, C.I. I. Solvent Blue 2, 5, 25, 44, C.I. I. Solvent Brown 3, 5, 37, C.I. I. Solvent Green 3, C.I. I. Solvent Black 3, 5, 7, 22, 23, 27, 29, 50, C.I. I. Direct Bulle 87, tartrazine and rhodamine 6G salt forming dye, Victoria pure blue and acid phthalocyanine blue salt forming dye, acid black 52 and organic amine salt forming dye, plus other chromium complex dye, cobalt complex A dye etc. can be illustrated. These dyes may be used alone or in combination of two or more. The blending amount may be appropriately determined depending on the solubility or the desired hue, density, etc., but it is preferably 1 to 20% by weight, preferably 2 to 15% by weight in the ink composition. When a metal complex dye is used, light resistance is improved. By adopting a dye, an oil-based ink that has good color developability, can freely select a hue, and is stable over time can be obtained.

  Furthermore, the oil-based ink of the present invention can be blended with polypropylene glycol having a molecular weight of 200 to 800 as a secondary solvent. When specific polypropylene glycol is blended, the dryness of the board surface and the printing surface when the stamp stand, vermilion and the penetrating mark lid are left open is further improved, and the ink ejection property and ink replenishment property to the ink occlusion body are further improved. It becomes good. In the present invention, the polypropylene glycol is 5 to 30% by weight, preferably 10 to 25% by weight, in the ink composition.

The oil-based ink of the present invention is prepared by blending appropriate amounts of each of the above substances so that the viscosity at normal temperature is 500 mPa · s or more and less than 1000 mPa · s.
Since the present invention is intended for absorbent paper, and excludes metal, glass, vinyl, and vinyl-coated paper that does not absorb ink, no resin is required. On the contrary, it is not preferable to blend a resin because it is difficult to adjust the viscosity, the viscosity increases with time, and it is easy to form a gel ink. In addition, higher fatty acids, higher fatty acid esters, dye dissolution aids such as alkyl ether phosphates, surfactants such as polyoxypropylene glycol and glycerin polyoxypropylene triol, pH adjusters, antiseptic / antifungal agents, rust preventives, An antioxidant or the like can be appropriately blended.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
Example 1
Polyoxyethylene polyoxypropylene monobutyl ether 65.0% by weight
Propylene glycol 30.0% by weight
C. I. Basic Blue 7 4.8% by weight
Antioxidant 0.2% by weight
The above components were mixed with a stirrer to obtain a blue oil-based ink having a viscosity at 20 ° C. of 600 mPa · s.

(Comparative Example 1)
All the propylene glycols of Example 1 were changed to polyoxyethylene polyoxypropylene monobutyl ether, and a blue oil-based ink was obtained in the same manner.

(Example 2)
Polyoxyethylene polyoxypropylene monobutyl ether 35.0% by weight
Polypropylene glycol (molecular weight 400) 35.0% by weight
Propylene glycol 20.0% by weight
C. I. Solvent Black 27 9.8% by weight
Antioxidant 0.2% by weight
The said component was mixed with the stirrer and black oil-based ink whose viscosity in 20 degreeC is 650 mPa * s was obtained.

(Comparative Example 2)
All the propylene glycol of Example 2 was changed to polyoxyethylene polyoxypropylene monobutyl ether, and a black oil-based ink was obtained in the same manner.

Example 3
Polyoxyethylene polyoxypropylene monobutyl ether 45.0% by weight
Polypropylene glycol (molecular weight 400) 35.0% by weight
Propylene glycol 10.0% by weight
C. I. Solvent Red 132 9.8% by weight
Antioxidant 0.2% by weight
The above components were mixed with a stirrer to obtain a red oil-based ink having a viscosity at 20 ° C. of 660 mPa · s.

(Comparative Example 3)
All the propylene glycols of Example 3 were polyoxyethylene polyoxypropylene monobutyl ether, and a red oil-based ink was obtained in the same manner.

Hereinafter, the oil-based inks of Examples 1 to 3 and Comparative Examples 1 to 3 were each impregnated into a polyurethane stamp stand having open cells, and each test was performed. The test results are shown in Table 1.
Moreover, each test was done by impregnating each of the oil-based inks of Examples 1 to 3 and Comparative Examples 1 to 3 with a polyethylene penetrating mark having open cells. The test results are shown in Table 2.
(Test method and evaluation criteria)
* The objects to be stamped were coated paper, art paper, and PPC recycled paper.
1. Bleeding test: The imprint was visually observed.
○… No bleeding △… There is little bleeding ×… With bleeding See-through test: Imprints were visually observed.
○… No through-through △… There is a slight through-through ×… With through-through 3. Setting time: After imprinting, the paper was piled up and a force of 1 kg / cm ² was applied, and the time until transfer was stopped was measured.
4). Dryability test: The time until the surface of the board could not be stamped was measured in a state in which the lid of the stamp stand was left open. In a state where the penetrating mark cap was left open, the time until it became impossible to seal was measured.

(Table 1)

(Table 2)

Claims (2)

  A stamp stand or vermilion or penetrating oil-based ink comprising a polyoxyethylene polyoxypropylene monoalkyl ether as a main solvent, propylene glycol as a bleeding inhibitor, and a dye as a colorant, and having a viscosity of 500 mPa · Stamp base or vermilion or oil-based ink for penetrating stamp, characterized by being adjusted to s or more and less than 1000 mPa · s.   A stamp base or vermilion or penetrating oil-based ink obtained by mixing polypropylene glycol having a molecular weight of 200 to 800 as a co-solvent with the oil base ink for stamp base of claim 1.