Crayon

Details Crayon Crayon

1997-12-29

2001-03-20

Dixon, Merrick (Department: 1774)

Stock material or miscellaneous articles

Composite

Of epoxy ether

C428S515000, C428S519000, C428S521000, C428S500000

Reexamination Certificate

active

06203910

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a novel crayon.
BACKGROUND OF THE INVENTION
Crayons are known which comprise a pigment component, an organic solvent, a resin component, a gelling agent and the like. Specific examples of such crayons are those prepared by gelling raw materials, i.e. at least one of dibenzylidene sorbitol, derivatives thereof, tribenzylidene sorbitol and derivatives thereof and a resin component (Japanese Examined Patent Publication No. 23619/1979). These crayons have the features that they remain unchanged in properties at elevated temperatures, and stick well to the surface of various materials to which a crayon is applied (such as metals, plastics and so on), and that the crayon layer on the material becomes so hardened as to inhibit the transfer of color to other materials.
Also known are crayons further improved in hardness, adhesion to the surface of a material, writability and other properties (Japanese Examined Patent Publication No. 41716/1980). These crayons comprise (a) at least one species selected from cellulose resins and vinyl resins, (b) at least one species selected from ketone resins, xylene resins, amide resins and terpene resins, (c) at least one species selected from dibenzylidene sorbitol, tribenzylidene sorbitol and derivatives thereof, (d) at least one species selected from glycols, ethers of glycols, esters of glycols and esters of benzoic acid, and (e) a pigment component.
However, even these crayons need to be further improved in writability (or ease of writing) for application to a wide variety of materials.
Moreover, in recent years, various countries have raised safety criteria for crayons. Thus it is now desired to develop crayons which assure meeting such high safety criteria. Especially there is room for further improvement of organic solvents to be used in crayons. For example, an alcohol (especially ethanol) may be used as the solvent only if the increase of safety is intended. However, the use of alcohol as the solvent fails to impart satisfactory writability and adhesion.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide a crayon which can fulfill higher safety criteria and which is superior in both writability and adhesion.
The present inventors conducted extensive research to resolve the prior art problems and successfully prepared a novel crayon which can achieve the object. The present invention was completed in this way.
According to this invention, there is provided a crayon comprising a pigment component, a gelling agent, an organic solvent and a resin component, the organic solvent consisting of propylene glycol monomethyl ether and dipropylene glycol monomethyl ether.
DETAILED DESCRIPTION OF THE INVENTION
To produce a crayon according to the invention, both propylene glycol monomethyl ether (solvent A) and dipropylene glycol monomethyl ether (solvent B) are used as the organic solvent. The amount of the organic solvent (total amount of solvents A and B) in the crayon of the invention is suitably variable depending on the factors associated with the pigment component and other components, but is usually about 20 to about 80% by weight, preferably about 35 to about 60% by weight. If a more amount of the organic solvent is used, it is difficult to form a gel, whereas a less amount thereof makes it difficult to dissolve the other components, failing to form a homogeneous gel.
While the proportions of the solvents A and B to be used can be suitably determined depending on the factors associated with other components, usually a solvent A : solvent B weight ratio is 1:0.1-10, preferably 1:0.2-5.
Useful gelling agents are not limited and include those conventionally used for crayons (those prepared by a process involving gelation). It is preferred in the practice of the invention to use at least one of dibenzylidene sorbitols and tribenzylidene sorbitols. Namely at least one of dibenzylidene sorbitol, tribenzylidene sorbitol and derivatives thereof can be used in the practice of the invention.
Useful dibenzylidene sorbitol derivatives include, for example, dibenzylidene sorbitols having a benzylidene group substituted at an optional position of benzene nucleus with an alkyl group having 1 to 3 carbon atoms, such as [di-(p-methylbenzylidene)]-sorbitol, [di-(m-ethylbenzylidene)]-sorbitol, [di-(p-chlorobenzylidene)]-sorbitol, etc. Useful tribenzylidene sorbitol derivatives include, for example, tribenzylidene sorbitols having a benzylidene group at an optional position of benzene nucleus with an alkyl group having 1 to 3 carbon atoms, such as [tri-(p-methylbenzylidene)]-sorbitol, [tri-(m-ethylbenzylidene)]-sorbitol, [tri-(p-chlorobenzylidene)]-sorbitol, etc.
The amount of the gelling agent in the crayon of the invention can be suitably determined according to the type of gelling agent to be used and other factors, but is usually about 2 to about 12% by weight, preferably about 3 to about 10% by weight. If a more amount of the gelling agent is used, the gel hardness is too high, leading to decreased coloring ability, whereas a less amount thereof is responsible for difficulty of gelation.
Examples of the resin component include those conventionally used for the above-mentioned crayons prepared by gelation and are not limited. In the practice of the invention, it is favorable to use two types of resins, i.e. a film-forming resins and an adhesion-improving resin.
There is no limitation on the kind of film-forming resins to be used insofar as they can enhance the hardness of crayons and can form a tough film on the surface of a material to which a crayon is applied. Examples of useful film-forming resins are cellulose acetate butyrate, ethyl cellulose, acetyl cellulose and like cellulose resins, polyvinyl butyral, polyvinyl acetate, vinyl acetate-vinyl chloride copolymer resins, vinyl acetate-ethylene copolymer resins and like vinyl resins. These resins can be used either alone or in combination. Among them, it is preferred to use polyvinyl butyral containing up to 5% of acetyl group, 18 to 27% of hydroxyl group and at least 69% of butyral group and having a polymerization degree of 300 to 2,000.
There is no limitation on the kind of adhesion-improving resins to be used insofar as they can improve the adhesion to the surface of a material. Examples of such resins are ketone resins, xylene resins, amide resins, etc. Useful ketone resins include, for example, a condensate of cyclohexanone and formaldehyde. Useful xylene resins include, for example, a condensate of metaxylene and formalin. Useful amide resins include. for example, thermoplastic resins prepared by condensation polymerization of dimer acid and diamine or polyamine and having a molecular weight of about 4000 to about 9000. These adhesion-improving resins can be used either alone or in combination.
The amount of the resin component in the crayon of the invention may be varied depending on the type of resin component to be used, but is usually about 3 to about 45% by weight, preferably about 6 to about 40% by weight. A more amount of the resin component used excessively increases the gel hardness, resulting in lowered coloring ability, whereas a less amount thereof causes difficulty in gelation.
The proportions of the film-forming resin and the adhesion-improving resin to be used can be suitably determined depending on the factors associated with other components. Yet, usually a film-forming resin : adhesion-improving resin weight ratio is 1:0.1-5, preferably 1:0.2-3.
There is no restriction on the kind of pigment component to be used. The pigment component to be used can be any of conventional pigments and dyes. Pigments which can be used are, for example, titanium oxide, red iron oxide, Ultramarine Blue, Cobalt Blue, iron yellow, iron black, Titanium Yellow and like inorganic pigments, and condensed azo, Phthalocyanine Blue, Phthalocyanine Green, Indanthrone Blue, quinacridone, diketo-pyrrolo-pyrrole, dioxazine and like organic pigments. Conventional ext

Affiliated with

Also associated with

Rating

Crayon does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Crayon, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Crayon will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2523469