JPS63196675A - Opaque ink for writing board - Google Patents

Abstract

PURPOSE:To provide the title ink which gives opaque handwriting which is clearly visible even on transparent surfaces and has excellent erasability immediately after writing and after a certain period of time, containing a resin, a specified glycol ether ester, a coloring component composed of a pigment and TiO2 and an org. solvent. CONSTITUTION:0.5-12wt.% resin (A) such as polyvinyl butyral, cellulose derivative, etc., 0.5-20wt.% glycol ether ester (B) of formula I or II [wherein X is a 0-24C alkylene, an alkenylene, a hydroxyalkylene or phenylene; R1 and R2 are each H or CH3; R3 is a 1-30C alkyl or phenyl; R4 is a 5-29C (hydroxy) alkyl, a (hydroxy)alkenyl; n is 1-10] as an additive for imparting strippability, 1-35wt.% pigment (C) selected from the group consisting of org. pigments and fluorescent pigments and TiO2 (D) are added to 40-95wt.% org. solvent (E) having a b.p. of 70-180 deg.C such as an aliph. lower alcohol, an aliph. ketone, etc. The mixture is mixed with one another.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a marking ink for a writing board, and more particularly, the present invention relates to a marking ink for a writing board, and in particular, the handwriting marked on a writing board made of a surface material impermeable to ink is opaque. The present invention relates to an opaque ink for writing boards that has the ability to be easily erased by being lightly rubbed with an erasing material such as dry cloth or soft paper.

[Conventional technology]

In the past, there have been many proposals regarding this type of marking ink for writing boards (for example, Japanese Patent Publication No. 45-39892, Japanese Patent Application Laid-open No. 49-29, Japanese Patent Application Laid-open No. 51764-1989, Japanese Patent Application Laid-open No. 60-51,
Inventions described in publications such as No. 1-246272 and Japanese Patent Publication No. 61-46509 have been made, but these include water-discharging surface materials such as enamel, metal, and glass, and hydrophobic surface materials such as plastics. No ink has been found that exhibits excellent erasability on any surface material and provides opaque handwriting.

Particularly with writing boards made of transparent plastics such as acrylic resin, styrene resin, and vinyl chloride resin, the handwriting must be opaque, but with the ink of the prior art, this type of writing board requires erasability. Good handwriting has transparent handwriting and the outline is not clear, while opaque handwriting has difficulty erasing.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a marking ink for a writing board that provides handwriting that is clearly visible even on a transparent or dark-colored writing board surface and that exhibits good erasability regardless of the type of surface material.

[Means for solving problems]

The composition of the opaque ink for writing boards of the present invention includes a pigment selected from fluorescent pigments and organic pigments, titanium dioxide, a resin, and a glycol ether selected from the group of compounds represented by the following general formulas (1) and (2) as essential components. General formula (1) containing an ester and an organic solvent General formula (2) where X is an alkylene group having 0 to 34 carbon atoms, an alkenylene group, a hydroxyalkylene group or a phenylene group, R, , R□ is hydrogen or a methyl group, R1 is an alkyl group having 1 to 30 carbon atoms or a phenyl group, R1 is a carbon number 5
-29 alkyl group, alkenyl group, hydroxyalkyl group or hydroxyalkenyl group, n is 1-10
Each represents the number of . Therefore, -ooc-x-coo- in the general formula (1) is a residue of a dicarboxylic acid having 2 to 36 carbon atoms (preferably 4 to 18 carbon atoms),
Specifically, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosadiic acid, and tocosadiic acid. , fumaric acid, maleic acid, malic acid, tartaric acid, and phthalic acid. group, specifically hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid,
Palmitic acid, stearic acid, 11.7-tert-diacid, behenic acid, montanic acid, palmitoleic acid, oleic acid, erucic acid, ricinoleic acid, 12-hydroxystearic acid, isooctylic acid, isodecanoic acid, isolauric acid, isomyristin acid, fatty acid residues such as isopalmitic acid, isostearic acid, and isoaracic acid.As mentioned above, in the writing board ink of the present invention, a pigment selected from organic pigments and fluorescent pigments is combined with titanium dioxide as a coloring component. It is stably dispersed in the ink by the action of the resin.

Examples of the resin include cellulose derivatives such as ethyl cellulose, nitrocellulose, carboxymethyl cellulose, hydroxypropyl cellulose, cellulose acetate, and cellulose butyrate, polyvinylpyrrolidone, polyvinyl butyral, and vinylpyrrolidone-vinyl acetate.
) Vinyl polymers such as co-tlC1 vinyl chloride-vinyl acetate copolymers, arylsulfamide-formaldehyde condensation resins, and styrene-maleic acid copolymers. These resins are present in the ink composition from 0.5 to 12
It is used in a range of 1 to 6% by weight, preferably 1 to 6% by weight.

Examples of the organic pigments include insoluble azo, polyazo, anthraquinone, thioindigo, perinone and perylene, dioxazine, quinacridin, and phthalocyanine pigments, and easily dispersible processed pigments whose surface is treated with the resin. is preferably used.

The fluorescent pigment used is a daylight fluorescent pigment made of powder of a fluorescent dye-resin solid solution, and the fluorescent dye is brilliant sulfoflavin (C, 1°56205).
, Thio 7-7 Bi7 (C01,49005), He'y Ivy Yellow G (C,!, 4604), Fluorescei 7 (C, 1,45350), x O'in (C, 1,45380) , l:2-gummy 76G (C
, 1,45160), l:)-Gummy 7 B (C.

1.45170), etc., and the resins that serve as carriers for these dyes include polymethacrylic acid ester and vinyl chloride.
Examples include vinyl acetate copolymers, alkyd resins, aromatic sulfamide resins, urea resins, triazine resins, benzoguanamine resins, and cocondensation resins thereof. Suitable examples include fluorescent pigments made of a solid solution of a melamine-toluenesulfamide condensation resin or a triazine resin and the above-mentioned fluorescent dye.

The pigment selected from the organic pigments (as pure pigments) and fluorescent pigments is used in the ink composition in an amount of 1 to 35% by weight, preferably 2 to 25% by weight.

The glycol ether ester compound is a releasability-imparting additive that facilitates the erasure of ink handwriting, and the conditions of Although this is a restriction in terms of availability, it is not preferable if the number of carbon atoms in R is less than 5 or if n exceeds 10, since the ink will swell the plastic material and impair the erasability of handwriting. The glycol ether ester compound is used in the ink composition in an amount of 0.5 to 20% by weight, preferably 4 to 15% by weight. If the ink contains less than 0.5% by weight, the erasability of handwriting will be sufficient, but if the content exceeds 20% by weight, the supersaturated content will tend to precipitate, resulting in a lack of ink stability and contamination of the writing board surface.

Incidentally, the glycol ether ester is synthesized by a conventional esterification reaction between a corresponding glycol monoether and a carboxylic acid.

If necessary, in addition to the glycol ether ester, an ester-based release-imparting additive such as dibasic acid ester, polyoxyethylene phosphate ester, polyoxyethylene sulfate ester, glyceride, and liquid polyester may be used in combination.

The solvent should be 70 to 18% so that the resin can be dissolved or dispersed, and the ink on the writing board can dry quickly.
An organic solvent with an i point in the range of 0°C is used. Specifically, aliphatic lower alcohols such as ethyl alcohol, propyl alcohol, butyl alcohol, aliphatic ketones such as methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbons such as toluene and xylene, lower fatty acid esters such as butyl acetate, etc. These solvents are used in an amount of 40 to 95% by weight in the ink composition.

[For production]

The ink for writing boards of the present invention uses a pigment selected from organic pigments and fluorescent pigments in combination with titanium dioxide as coloring components, so that it can be clearly seen even on writing boards made of transparent materials or darkly colored surfaces. Due to the action of the glycol ether ester additive, which provides handwriting that can be easily drawn and gives releasability to the handwriting, the decrease in erasability of handwriting caused by the addition of titanium dioxide can be resolved, and the surface material can be made of various surface materials with different chemical properties. The glycol ether ester, which has the ability to show good handwriting erasability on any writing board, is dissolved in the organic solvent and stably exists in the ink, and when handwriting is formed, it disappears from the writing board. It prevents the resin in the ink from firmly adhering to the board surface, contributing to the erasability of handwriting. Since the compound has a well-balanced structure of parent xylem and hydrophobic parts in its molecule, it exhibits affinity for the writing board surface regardless of the chemical properties of the hydrophilic or hydrophobic surface material, and exhibits the above-mentioned effects. It is thought that this will fulfill the following requirements. Furthermore, the compound itself is nonvolatile, and its action continues even after handwriting is formed and time passes.

〔Example〕

(1) Preparation of ink 90 parts by weight of ethanol and 10 parts by weight of polyvinyl butyral resin
A predetermined amount of glycol ether ester is added to a solution prepared by dissolving a part of glycol ether ester or methyl isobutyl ketone, and the mixture is heated at about 30°C.
A predetermined amount of a processed pigment dispersion or fluorescent pigment prepared in advance as described below and a titanium dioxide dispersion prepared as described below are added to the vehicle obtained by heating and dissolving the mixture at high speed. The mixture was stirred for about 1 hour using a separate mixer to obtain 6 types of example inks.

The processed pigment dispersion was obtained by adding 20 parts by weight of the processed pigment to 80 parts by weight of isopropanol and dispersing the mixture in a paint conditioner for 2 hours.

The titanium dioxide dispersion was obtained by adding 50 parts by weight of titanium dioxide to a solution prepared by dissolving 1 part by weight of polyvinyl butyral in 49 parts by weight of isopropanol, and dispersing the solution with a paint conditioner for 2 hours.

Four types of comparative inks were also prepared in which other additives were added in place of the glycol ether ester in the above ink formulation, or no glycol ether ester was added.

The raw materials used for each ink are as follows.

・Organic pigment (processed pigment with a pigment/resin ratio of approximately 1/1) Green processing pigment: Green pigment surface-treated with polyvinyl butyral (C, 1, Pigment Green 7) Red processing material: Vinyl chloride-vinyl acetate copolymer Red pigment surface-treated with (C, 1, Pigment Red 15) Fluorescent pigment Yellow fluorescent pigment; Yellow fluorescent dye (thioflavin.

C, 1,49005) and a triazine resin: Pink fluorescent dye (Rhodamine 6
・Titanium dioxide rutile type titanium dioxide ・Resin polyvinyl butyral L: average degree of polymerization approximately 280, degree of butyralization 63 ± 3 mol%, acetylation polyvinyl butyral M: average degree of polymerization of approximately 650, butyralization degree of 65±3 mol%, degree of acetylation of 3 mol% or less ・Glycol ether ester Glycol ether ester A-C is expressed by the following general formula (1)
General formula (1) % Formula % (described on the next page) Glycol ether esters D to F are as shown below 8 Formula (2)
R, , R1, R, and n are shown in Table 2 below, respectively.
Compound general formula (2), which is a group or number as shown in ・Other additives (used in comparative example ink) Fatty acid ester P: 2-ethylhexanoic acid stearic acid fatty acid ester Q
Butyl nistearate liquid paraffin/organic solvent ethanol, isopropanol, methyl isobutyl ketone Composition of example ink and comparative example ink (expressed in parts by weight)
are shown in Table 3.

(2) Handwriting erasability test Examples and A sample pen is prepared by filling a predetermined amount of each ink of the comparative example.

A line of a predetermined shape was drawn on the surface of a transparent acrylic resin board using each sample pen, and the erasability was tested initially and after aging (two methods: 1 month at room temperature and 2 weeks at 40°C).

The erasing test used an erasing tool whose erasing surface was made of felt.
This was done by rubbing once under a load of 300±10 g/am''.

In determining the quality of erasability, both the removability of handwriting and the presence or absence of stain on the board surface after peeling were observed and judged.

Regarding the visibility of the handwriting on the surface of the transparent plate, all the sample inks had clear handwriting with clear outlines.

The test results are shown in Table 4.

Claims (1)

[Scope of Claims] A pigment selected from fluorescent pigments and organic pigments, titanium dioxide, a resin, a glycol ether ester selected from the group of compounds represented by the following general formulas (1) and (2), and an organic solvent as essential components. An opaque ink for writing boards comprising: General formula (1) R_3-(OCHR_2CHR_1)_n-OOC-X
-COO-(CHR_1CHR_2O)_n-R_3 General formula (2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Here, X is an alkylene group having 0 to 34 carbon atoms, an alkenylene group, a hydroxyalkylene group, or a phenylene group, R_1, R_2 is hydrogen or a methyl group, R_3 is an alkyl group having 1 to 30 carbon atoms or a phenyl group, R_4 is an alkyl group, alkenyl group, hydroxyalkyl group, or hydroxyalkenyl group having 5 to 29 carbon atoms, n is 1
Each represents a number from 1 to 10.