JP4776932B2 - Non-absorbing surface erasable crayon - Google Patents

Description

  The present invention relates to a crayon that can be erased on a solid non-absorbing surface that can be written on a non-absorbing surface such as a white board and can be erased when the handwriting is rubbed with an eraser such as a nonwoven fabric.

Conventionally, a crayon that can be written on a non-absorbing surface such as a white board and can be erased by a solid non-absorbing surface comprising a resin, a release agent and a gelling agent, which can be erased when the handwriting is rubbed with an eraser such as a nonwoven fabric, No. 54-23618 (refer to Patent Document 1). Further, crayon erasable with a solid non-absorbing surface using soap or Wax is also known (see Patent Documents 2 to 4).
Japanese Patent Publication No.54-23618 Japanese Patent Laid-Open No. 8-12917 JP-A-8-113753 Japanese Patent Laid-Open No. 51-9930

  However, the crayon using the above gelling agent has a problem that the release agent hardly moves in the writing line, so that sticking to the plate surface easily occurs and erasing cannot be performed with a light touch. In addition, a crayon using soap or Wax has a problem that it cannot be erased like a liquid white board ink because a uniform coating film is not formed.

  An object of the present invention is a crayon that can be written on a non-absorbing surface such as a white board and can be erased when the handwriting is rubbed with an eraser such as a non-woven fabric, and can be erased on a solid non-absorbing surface, forming a uniform coating It is to improve the leveling of the coating film, achieve erasability like white board ink, and also provide a crayon that can be erased with a non-absorbing surface that can be erased with a light touch without sticking to the white board etc. .

  The present invention comprises at least an organic solvent, a resin soluble in the organic solvent, dibenzylidene sorbitol or tribenzylidene sorbitol and derivatives thereof, oil, and a colorant, and the colorant / resin soluble in the organic solvent = 1. It was found that the above-mentioned problem can be achieved by using a non-absorbing surface erasable crayon characterized by /0.5 to 1/2, and the present invention has been completed based on this finding. . Further, the organic solvent is propylene glycol alkyl ether, dipropylene glycol alkyl ether, ethylene glycol alkyl ether and one or more of esterified products thereof or 3-methoxy-butanol, and the resin is a cellulose resin. This problem is further improved by setting the oil to a boiling point of 200 ° C. or higher, which is difficult to be compatible with the resin.

  The present invention comprises at least an organic solvent, a resin soluble in the organic solvent, dibenzylidene sorbitol or tribenzylidene sorbitol and derivatives thereof, an oil and a colorant, and is soluble in the colorant / the organic solvent. It is possible to write on a non-absorbing surface such as a white board by using a non-absorbing surface erasable crayon characterized in that the resin is 1 / 0.5 to 1/2, and the handwriting is an eraser such as a non-woven fabric. It is a crayon that can be erased with a solid non-absorbing surface that can be erased by rubbing with, and by forming a uniform coating film, the leveling property of the coating film is improved and erasability like white board ink is realized, and further, the white board Eliminates sticking to etc. and can be erased with a light touch.

(Organic solvent)
The organic solvent is not particularly limited, but aromatic hydrocarbons such as xylene and tetralin, cyclohexane hydrocarbons having 9 and 10 carbon atoms such as n-propylcyclohexane and n-butylcyclohexane, and ketones such as methyl isobutyl ketone. , Butyl acetate, propionic acid esters, monohydric alcohols, glycols, glycol ethers, and known organic solvents such as these esters can be used, but glycols, glycol ethers, glycol ether esters, alcohols It is preferable to use at least one kind from the class. For example, alcohols such as methanol, ethanol, isopropyl alcohol, 3-methyl-3-methoxybutanol and 3-methoxy-1-butanol, glycols such as ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol, and methyl ethers of the above glycols Glycol ethers such as ethyl ether, propyl ether, butyl ether and phenyl ether, or esters thereof.

  Especially in the present invention, among them, propylene glycol alkyl ethers such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol alkyl ether, It is preferable to use ethylene glycol alkyl ethers and esterified products thereof (alkyl n is preferably 1 to 4) or one or more of 3-methoxy-butanol.

  The content of the organic solvent in the crayon can be appropriately set in relation to the components such as the colorant, but is usually about 20 to 80% by weight, preferably 30 to 60% by weight. When the organic solvent exceeds 60% by weight, gelation is difficult and solidification is difficult, the crayon becomes soft, and uniform handwriting cannot be obtained. On the other hand, if it is less than 20% by weight, the resin is difficult to dissolve, and the pigment is difficult to disperse.

(Gelling agent)
As the gelling agent, dibenzylidene sorbitol and its derivatives, tribenzylidene sorbitol and its derivatives can be used. Examples of dibenzylidene sorbitol and its derivatives include dibenzylidene sorbitol and compounds substituted with an alkyl group having 1 to 3 carbon atoms in the benzylidene group at an arbitrary position of the benzene nucleus in dibenzylidene sorbitol (dibenzylidene sorbitol derivatives). Specifically, [G (p-methylbenzylidene)]-sorbitol, [G (m-ethylbenzylidene)]-sorbitol, [G (p-chlorobenzylidene)]-sorbitol and the like can be mentioned.

  Examples of tribenzylidene sorbitol and derivatives thereof include tribenzylidene sorbitol and compounds substituted with an alkyl group having 1 to 3 carbon atoms in the benzylidene group at any position of the benzene nucleus in tribenzylidene sorbitol (tribenzylidene sorbitol derivatives). Specific examples include [Tory (p-methylbenzylidene)]-sorbitol, [Tory (m-ethylbenzylidene)]-sorbitol, [Tory (p-chlorobenzylidene)]-sorbitol, and the like.

  The content of the gelling agent in the crayon can be appropriately set according to the type of the gelling agent to be used, but is usually about 5 to 25% by weight, preferably 6 to 20% by weight. If the gelling agent exceeds 25% by weight, the crayon becomes too hard to write. If it is less than 5% by weight, it is difficult to solidify, the crayon becomes soft and uniform handwriting cannot be obtained.

(resin)
As the resin used in the crayon of the present invention, a resin soluble in the above organic solvent can be used, and it functions to stably disperse a colorant such as a pigment, becomes a coating film after writing, and can be scraped off from a white board at the time of erasure. it can. Specifically, cellulose resins such as cellulose acetate butyrate, ethyl cellulose, and acetyl cellulose; polyvinyl resins such as polyvinyl butyral, polyvinyl acetate, vinyl acetate-vinyl chloride copolymer resin, vinyl acetate-ethylene copolymer resin, etc. it can. Cellulosic resins such as cellulose acetate butyrate, ethyl cellulose, and acetyl cellulose are preferred.

  The content of the resin in the crayon is usually about 1 to 30% by weight, preferably 2.5 to 20% by weight. If the amount of the resin exceeds 30% by weight, the crayon becomes too hard to write and causes sticking during erasure. If it is less than 1% by weight, the dispersibility of the pigment cannot be obtained, and color residue at the time of erasure is caused.

  In the present invention, a colorant can be used. By using the colorant, the color of the crayon can be adjusted to various colors. As the colorant, those having good solubility and dispersibility are preferable. Specifically, inorganic and organic pigments and oil-soluble dyes can be used as the colorant, and inorganic and organic pigments can be preferably used. Preferred examples of the inorganic and organic pigments include titanium oxide, dial, carbon black, carmine 6B, selenium blue, phthalocyanine blue, phthalocyanine green, DPP red, dioxazine, and azo pigments.

  In the present invention, the content of the colorant is 2 to 30% by weight, preferably 5 to 20% by weight. If it is less than 2% by weight, sufficient color development as a crayon cannot be obtained. On the other hand, if it exceeds 30% by weight, the dissolution of the dye or the dispersion stability of the pigment cannot be obtained.

  In the present invention, it is important that the colorant / resin soluble in the organic solvent = 1 / 0.5 to 1/2. When the resin soluble in the colorant / organic solvent exceeds 1 / 0.5, there is a problem that the handwriting extends at the time of erasing, and when it is less than 1/2, it causes sticking at the time of erasing and the time passes. Eraseability deteriorates.

(paint remover)
The release agent of the present invention is used for imparting erasability of the coating film written on the non-absorbing surface, and is usually butyl laurate, isopropyl myristate, butyl myristate, ethyl palmitate, isopropyl palmitate, stearin. Fatty acid such as methyl acid and butyl stearate and fatty alcohol ester or liquid paraffin can be used, and liquid oil is preferred among them. Furthermore, it is preferable to use a resin having a boiling point of 200 ° C. or higher that is hardly compatible with the resin. This is because the oil exists in a phase-separated state between the white plate and the coating film made of resin or the like, and improves the erasability of the handwriting. Specifically, fatty acid esters such as normal butyl stearate are preferred.

  The content of the release agent is 5 to 30% by weight, preferably 10 to 25% by weight. If it exceeds 30% by weight, the color residue of the handwriting at the time of erasure occurs, and the crayon is soft and uniform handwriting cannot be obtained. On the other hand, if it is less than 5% by weight, sticking may occur during erasure.

(Other additives)
In the crayon of the present invention, known additives such as a filler, a leveling agent, a viscosity modifier, a structural viscosity imparting agent, and a drying property imparting agent can be appropriately blended as other components as necessary. In addition, plasticizers such as diethyl phthalate, dibutyl phthalate, dioctyl phthalate, 2-ethylhexyl epoxyhexahydrophthalate, 2-ethylhexyl sebacate, tricresyl phosphate, and the like can be appropriately blended.

  In the method for producing a crayon of the present invention, basically, the above-described components may be mixed uniformly. That is, a release agent is added to the organic solvent, then a colorant is added, and the mixture is stirred and mixed. Thereafter, the resulting mixture is heated to near the boiling point of the organic solvent to dissolve the gelling agent, and thus obtained. The homogeneous mixture may be poured into a container having a desired shape and cooled and solidified.

  Examples and Comparative Examples are shown below, and the features of the crayon capable of being erased by the non-absorbing surface of the present invention will be described more specifically.

  Table 1 shows the compositions and results of Examples 1 to 5 and Comparative Examples 1 to 3 manufactured based on the manufacturing method described above.

≪Evaluation test≫
(Preparation of test sample)
The crayons of the compositions of Examples 1 to 5 and Comparative Examples 1 to 3 produced by the above-described manufacturing method were filled in a predetermined container, cooled and solidified to form a rod-shaped crayon, and the writing property and erasability were evaluated.

(Evaluation)
・ Writing ability Written letters are written on a white board with a 200g load immediately after the crayon is manufactured, and written uniformly on the white board without bleeding or blurring. In this example, “○” indicates that the writing can be performed without any problem, and “×” indicates that the writing line has considerable bleeding and blurring and cannot be written.
Erasability Erasability is determined by writing a predetermined symbol on the white board while applying a load of 200 g immediately after crayon preparation, and rubbing the above writing line while applying a load of 200 g to the eraser after 5 minutes. Then, the number of scratches was counted until the writing line could be erased. When the number of scratches was 10 or less, “「 ”was given, and when it exceeded 10 and 20 or less,“ ◯ ”was given, and when it exceeded 20 times,“ X ”was given.

From the results of Table 1, Examples 1 to 5 were excellent in both writing property and erasability, but Comparative Examples 1 and 2 were poor in writing property, and Comparative Examples 1 and 3 were inferior in erasing property.

Claims (2)

As an organic solvent, at least propylene glycol alkyl ether, dipropylene glycol alkyl ether and esterified product thereof, one or more of esterified ethylene glycol alkyl ether , cellulose acetate butyrate, dibenzylidene sorbitol or tribenzylidene sorbitol and their A non-absorbing surface erasable crayon comprising a derivative, a release agent and a colorant, wherein the colorant / cellulose acetate butyrate = 1 / 0.4 to 1 / 2.4.   The crayon capable of being erased on the non-absorbing surface according to claim 1, wherein the release agent has a boiling point of 200 ° C. or higher which is hardly compatible with the resin.