JP3184274B2 - Thermal recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to an improvement in a heat-sensitive recording material provided with a heat-sensitive coloring layer which is colored by heat on a support.

[0002]

2. Description of the Related Art A thermosensitive recording material generally comprises a support such as paper, synthetic paper, plastic film and the like, on which a thermosensitive coloring layer mainly comprising a thermochromic composition is provided. By heating with a strobe lamp or the like, a colored image can be obtained. This type of recording material does not require complicated processing such as development and fixing compared to other recording materials,
It is used for copying books, documents, etc. due to its advantages such as being able to record in a short time with a relatively simple device, generating less noise and environmental pollution, and being inexpensive, as well as electronic computers, facsimile machines, It is widely used as a recording material in various fields such as ticket vending machines, labels, and recorders. The thermochromic composition used in such a thermosensitive recording material comprises a general color former and a developer which causes the color former to develop color when heated.Examples of the color former include lactone, lactam or colorless having a spiropyran ring. Alternatively, a light-colored leuco dye has been used, and as a developer, an organic acid or a phenolic substance has been conventionally used. The recording material in which the color former and the developer are combined has the advantages that the obtained image has a particularly clear color tone, a high whiteness of the background, and excellent weather resistance of the image. , Widely used.

However, this kind of thermal recording material is DOA or D
When it comes into contact with a plasticizer such as OP or oils and fats, there is a disadvantage that an image is erased or a background portion is colored.
In order to overcome these drawbacks, a protective layer has conventionally been provided on the heat-sensitive coloring layer. Components of the protective layer include a water-soluble resin such as polyvinyl alcohol and starch, and a glyoxal or epoxy compound. Fillers such as calcium carbonate and silica and waxes have been used as a matching improving aid for such crosslinking agents.

Further, since a water-soluble resin is used for the protective layer,
There is a problem that the water-proof strength is low and the protective layer is peeled off when it comes into contact with water. Therefore, it is customary to add a crosslinking agent. For example, a mixture of polyvinyl alcohol and an epoxy compound having two or more epoxy groups or an ethylene imine compound having two or more ethylene imine groups (Japanese Patent Application Laid-Open No. 60-68990), a casein and a compound having a methylol group are used. What was used (Japanese Unexamined Patent Publication No.
No. 0-193693), those using an acrylamide-acrylonitrile-carboxyl group-containing vinyl compound copolymer and an epoxy resin (JP-A-61-37467),
Polyvinyl alcohol and 2,4-dihydroxy-1,4
Using a dioxane derivative (JP-A-62-444)
No. 94) and those using bis (4-glycidyloxyphenyl) sulfone as a cross-linking agent (JP-A-62-27).
No. 0382) has been proposed. However, the pot life of the coating liquid is short, for example, the viscosity of the coating liquid increases with time, and the crosslinking effect decreases with time, like an ethyleneimine compound. There are drawbacks such as insufficient.

[0005]

SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned problems, and is excellent in image reliability such as water resistance, oil resistance and plasticity resistance , and has a long pot life of a coating solution , and a heat-sensitive recording material .
Thermosensitive label sheet using it, thermosensitive recording magnet
The purpose is to provide vouchers .

[0006]

According to the present invention, there is provided on a support, a thermosensitive coloring layer mainly composed of a leuco dye and a developer capable of causing the leuco dye to be colored by heat, and further thereon. In a thermosensitive recording material provided with a protective layer containing a resin and a crosslinking agent as main components, the crosslinking agent has the following structural formula
A heat-sensitive recording material using a methyl ethyl ketoxime derivative having a group represented by (1).

Embedded image Is provided.

On a support, a thermosensitive coloring layer mainly composed of a leuco dye and a color developer capable of coloring the leuco dye by heat is provided, and further a resin and a crosslinking agent are further composed thereon. In a thermosensitive recording material provided with a protective layer, a bis (β ) represented by the following structural formula (2) is used as the crosslinking agent.
-Hydroxyethyl) sulfone using a thermosensitive recording material

Embedded image Is provided.

[0008] Further, a heat-sensitive recording label sheet characterized in that a release liner is provided via an adhesive on a surface of the support of the heat-sensitive recording material described above, which is opposite to the surface on which the heat-sensitive coloring layer is provided. And a heat-sensitive recording type magnetic sheet characterized in that a magnetic recording layer mainly comprising a ferromagnetic material and a binder is provided on the opposite surface.

That is, the present inventors have conducted intensive studies on a protective layer comprising a resin and a cross-linking agent provided on a heat-sensitive color-forming layer in a heat-sensitive recording material. In such a case, it was found that the intended purpose could be achieved, and the present invention was completed.

Specific examples of the methyl ethyl ketoxime derivative having a group represented by the structural formula (1) used as a crosslinking agent in the present invention include the following structural formula
Those represented by (3), (4) or (5) are mentioned.

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Further, in the present invention, together with the crosslinking agent of the present invention, a crosslinking agent conventionally used, for example, formalin, chromium alum, glyoxal, boric acid, an amine compound, an epoxy compound, a polyamide epichlorohydrin compound, It can be used in combination with glycidyl compounds, methylol compounds, ethyleneimine compounds and the like.

The resin used in the protective layer of the present invention includes, for example, polyvinyl alcohol, cellulose derivatives, starch and derivatives thereof, carboxyl group-modified polyvinyl alcohol, polyacrylic acid and derivatives thereof, styrene / acrylic acid copolymer and derivatives thereof , Poly (meth) acrylamide and derivatives thereof, styrene / acrylic acid / acrylamide copolymer, amino group-modified polyvinyl alcohol, epoxy-modified polyvinyl alcohol, polyethyleneimine, aqueous polyester, aqueous polyurethane, maleic anhydride copolymer and derivatives thereof Such as water-soluble resin, polyester, polyurethane, acrylate (co) polymer, styrene / acrylic copolymer, epoxy resin, polyvinyl acetate, polyvinylidene chloride, polyvinyl chloride and the like. The aqueous emulsion resin conductors and the like. Among these, a water-soluble resin is preferable, and (modified) polyvinyl alcohol is particularly preferable, and among them, a completely saponified type and a polymerization degree of 1,000 or more is preferable.

When the above-mentioned alkylene imide compound is used as a cross-linking agent, a copolymer obtained from a (maleic anhydride) maleic acid monomer is particularly preferred as the resin for forming the protective layer.
Examples of such (anhydride) maleic acid copolymer include isobutylene-maleic anhydride copolymer, diisobutylene-
A maleic anhydride copolymer, an acryl-styrene-maleic acid copolymer and the like can be mentioned.

In the protective layer of the present invention, the resin
In addition to the crosslinking agent, if necessary, auxiliary additives commonly used in this type of heat-sensitive recording material, such as a filler, a surfactant, a heat-fusible substance (or a lubricant), and a pressure color-developing agent are used in combination. be able to. In this case, as the filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate,
In addition to inorganic fine powders such as clay, talc, surface-treated calcium and silica, urea-formalin resin, styrene
/ Organic fine powder such as methacrylic acid copolymer and polystyrene resin. Examples of the heat-fusible substance include higher fatty acids or esters, amides or metal salts thereof, various waxes, condensates of aromatic carboxylic acids and amines, phenyl benzoate, higher linear glycols, and the like. Those having a melting point of about 50 to 200 ° C, such as dialkyl 1,4-epoxy-hexahydrophthalate, higher ketones, p-benzylbiphenyl and other heat-fusible organic compounds.

In the present invention, the method of color development by heat is one that utilizes a color development reaction between a leuco dye and a developer, one that utilizes a reaction between a diazo compound and a coupler, and one that utilizes a reaction between an isocyanate and an amine. There are things to do. Since the feature of the present invention resides in the protective layer of the heat-sensitive recording material, the color forming method is not particularly limited. Hereinafter, the thermal recording method using a general leuco dye will be described.

In the present invention, the leuco dye used in the thermosensitive coloring layer is applied alone or in combination of two or more.
As such leuco dyes, those applied to this type of heat-sensitive material are arbitrarily applied, and examples thereof include triphenylmethane, fluoran, phenothiazine, auramine, spiropyran, and indolinophthalide. A leuco compound of a dye is preferably used. Specific examples of such leuco dyes include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis ( p-dimethylaminophenyl) -6-diethylaminophthalide,
3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7 -Dimethylfluoran, 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluoran, 3-N-ethyl-N-
Isoamyl-6-methyl-7-anilinofluoran, 3
-Diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7,8-benzfluoran, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3- (Np-tolyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluoran, 2
-{3,6-bis (diethylamino) -9- (o-chloroanilino) xanthyl lactam lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluoran, 3-diethylamino-7- (O
-Chloroanilino) fluoran, 3-dibutylamino-
7- (o-chloroanilino) fluoran, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N-cyclohexylamino-
6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (2 ′, 4′-dimethylanilino) fluoran, 3 -(N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino)
Fluoran, benzoyl leucomethylene blue, 6'-
Chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-3'-methoxy-benzoindolino-spiropyran, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2 ' -Methoxy-5 '
-Chlorophenyl) phthalide, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-nitrophenyl) phthalide, 3- (2'-
(Hydroxy-4'-diethylaminophenyl) -3-
(2′-methoxy-5′-methylphenyl) phthalide,
3- (2'-methoxy-4'-dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-
Methylphenyl) phthalide, 3-morpholino-7- (N
-Propyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7-
(N-benzyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluoran, 3-diethylamino-5
-Chloro-7- (α-phenylethylamino) fluoran, 3- (N-ethyl-p-toluidino) -7- (α-
Phenylethylamino) fluoran, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluoran, 3-diethylamino-5-methyl-7- (α
-Phenylethylamino) fluoran, 3-diethylamino-7-piperidinofluoran, 2-chloro-3-
(N-methyltoluidino) -7- (pn-butylanilino) fluoran, 3- (N-methyl-N-isopropylamino) -6-methyl-7-anilinofluoran, 3
-Dibutylamino-6-methyl-7-anilinofluoran, 3,6-bis (dimethylamino) fluorenespiro (9,3 ')-6'-dimethylaminophthalide, 3-
(N-benzyl-N-cyclohexylamino) -5,6
-Benzo-7- [alpha] -naphthylamino-4'-bromofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-N-ethyl-N- (2-ethoxypropyl) amino-6 Methyl-7-anilinofluoran, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-mesitidino-4 ′, 5 ′ −
Benzofluoran, 3-N-ethyl-N-isobutyl-
6-methyl-7-anilinofluoran and the like.

Examples of the color developing agent used in the thermosensitive coloring layer of the present invention include various electron-accepting compounds capable of coloring the leuco dye upon contact, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, and organic compounds. Acids and metal salts thereof are preferably applied, and specific examples thereof include the following.

4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis (o-methylphenol), 4,4'-secondarybutylidenebisphenol 4,4'-isopropylidenebis (2-tert-butylphenol) ), 4,4'-cyclohexylidenediphenol, 4,4'-isopropylidenebis (2
-Chlorophenol), 2,2'-methylenebis (4-
Methyl-6-tert-butylphenol), 2,
2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (6-tert-butyl-2-methylphenol), 1,1,1
3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2
-Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis (6-tert-butyl-2-methylphenol), 4,4'-diphenolsulfone, 4-isopropoxy-4'- Hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, isopropyl P-hydroxybenzoate, P-
Benzyl hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-
(Hydroxyphenylthio) -3-oxapentane, 1,
3-bis (4-hydroxyphenylthio) -propane,
1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N′-diphenylthiourea,
N, N′-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid Metal salts of hydroxy, naphthoic acid such as zinc, aluminum and calcium, bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4-hydroxyphenyl) acetic acid benzyl ester, 1,3-bis (4-hydroxycumyl) ) Benzene, 1,4-bis (4-hydroxycumyl) benzene, 2,4′-diphenolsulfone, 3,3′-diallyl-4,4′-diphenolsulfone, α, α-bis (4- (Hydroxyphenyl) -α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobi Sphenol S and the like.

In order to produce the heat-sensitive recording material of the present invention,
When the leuco dye and the developer are bound and supported on the support, various conventional binders can be appropriately used, and specific examples thereof include the following.

Polyvinyl alcohol, starch and derivatives thereof, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, cellulose derivatives such as methyl cellulose, ethyl cellulose, etc .; -Da, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkaline salt, isobutylene / maleic anhydride copolymer alkaline salt , Polyacrylamide, sodium alginate, gelatin, casein, as well as water-soluble polymers, polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylate, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate G, ethylene / vinyl acetate Emulsion and styrene / butadiene copolymers such as the body, styrene / butadiene / latex such as acrylic copolymer.

In the heat-sensitive coloring layer of the present invention, if necessary, auxiliary additives commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, heat-sensitive materials, together with the leuco dye and the developer. A fusible substance (or lubricant), a pressure coloring inhibitor, and the like can be used in combination. In this case, specific examples of the filler and the heat-fusible substance include those similar to those exemplified in relation to the protective layer.

In the present invention, an undercoat layer can be provided between the support and the heat-sensitive coloring layer, if necessary. In this case, as the components constituting the undercoat layer, the above-mentioned filler, binder, heat-fusible substance, surfactant and the like can be used. Further, in the present invention, two or more protective layers can be formed, and a back coat layer can be provided.

The heat-sensitive recording material of the present invention is used in various fields. In particular, the heat-sensitive recording material utilizes the above-described excellent color-developed image and the stability of the background portion, and can be used as a heat-sensitive recording label sheet,
It can be advantageously used as a thermosensitive recording type magnetic ticket. In the case of a heat-sensitive recording type label sheet, a heat-sensitive coloring layer containing the leuco dye and a developer described above and the protective layer are provided on one surface of the support, and the other surface of the support is provided with an adhesive layer interposed therebetween. What is necessary is just to provide a peeling mount, and in the case of magnetic ticket paper,
A magnetic recording layer mainly composed of a ferromagnetic material and a binder may be provided instead of the release liner.

[0025]

The present invention will be described in more detail with reference to the following examples. The following parts and percentages are all based on weight.

Examples 1 to 8 and Comparative Examples 1 to 4 [Formation of thermosensitive coloring layer] A mixture having the following composition was pulverized and dispersed by a sand grinder for 2 to 4 hours, respectively, to obtain [Solution A] and [Solution B]. Prepared. [Solution A] 3- (N-methyl-N-cyclohexyl) amino-6-10 parts methyl-7-anilinofluoran 10% aqueous solution of polyvinyl alcohol 10 parts Water 80 parts [Solution B] 4-hydroxyphenyl-4 '-Isopropoxyphenyl sulfone 10 parts Calcium carbonate 10 parts 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane 5 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water 55 parts [Liquid A] and [Liquid B] were dispersed in a sand mill for 24 hours to obtain respective dispersions, and the weight ratio was [Liquid A]: [Liquid B].
= 1: 3 to prepare a coating solution for the thermosensitive coloring layer, which was dried on a commercially available high-quality paper to have a coating weight of 50 g / m ² ,
The coated paper was dried so as to have a dry weight of 5 g / m ² to obtain a paper coated with a thermosensitive coloring layer.

[Formation of Protective Layer] [Solution C] Silica 10 parts Polyvinyl alcohol 10% aqueous solution 10 parts Water 80 parts [Solution C] was dispersed in a sand mill for 15 hours to obtain a silica dispersion. [D₁Liquid] to [D_FourLiquid), [E₁Liquid) to [E_FourLiquid], [F₁liquid〕~ [F _Four liquid〕  Silica dispersion 20 parts Resin (shown in Table 1) 10% aqueous solution 40 parts Crosslinking agent (shown in Table 1) 10% aqueous solution (dispersion) 1 part Water 49 parts [D₁liquid〕~[F _Four liquid〕Each on the heat-sensitive coloring layer-formed paper
Has a dry weight of 3 g / m^TwoApply and dry so that it becomes a protective layer
Was formed. Furthermore, surface treatment is performed with a super calendar.
Example 18To obtain the heat-sensitive recording materials of Comparative Examples 1 to 4.
Was.

[0028]

[Table 1]

The heat-sensitive recording materials obtained in Examples 1 to 8 and Comparative Examples 1 to 4 were measured for plasticizer resistance, water resistance and liquid resistance by the methods described below. Table 2 shows the results.・ Plasticizer resistance Using a heat block, the density in a Macbeth densitometer is 1.3.
DOA was applied to the area where the color was developed to 0, and 30 ° C., 16
After an hour, the concentration was measured with a Macbeth densitometer. Water resistance: After leaving at 40 ° C. for 16 hours, it was immersed in water for 16 hours, and rubbed with a finger to evaluate the peeling state. ○: good without peeling, △: slight peeling ×: poor peeling ・ Liquidity The viscosity of the liquid after leaving the coating liquid at 30 ° C. for 24 hours, and The composition was applied again on the thermosensitive coloring layer, subjected to the same liquid property test, and compared with a sample obtained using the liquid immediately after the preparation.・ ・ ・: Same level as immediately after mixing △: Slightly inferior than immediately after mixing ×: Inferior than immediately after mixing

[0030]

[Table 2]

[0031] Example 1-8, as apparent from Comparative Examples 1 to 4, as a crosslinking agent for forming a protective layer in the heat-sensitive recording material of the present invention, the specific methyl ethyl ketoxime derivative or bis, (beta- By using (hydroxyethyl) sulfone, the pot life is long with the protective layer forming liquid, and the obtained heat-sensitive recording material is excellent in plastic resistance and water resistance.

[0032]

Heat-sensitive recording material of the present invention exhibits, in the heat-sensitive coloring layer, a resin and, as a main component a specific methyl ethyl ketoxime derivative or bis (beta-hydroxyethyl) crosslinking agent selected from sulfone, By providing the protective layer, the image reliability such as plasticizer resistance and the like are excellent, and the water resistance is also good. By using the crosslinking agent, the pot life of the coating liquid for forming the protective layer is long.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-301456 (JP, A) JP-A-63-264394 (JP, A) JP-A-3-197171 (JP, A) JP-A 64-64 69385 (JP, A) JP-A-1-263078 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/28-5/34

Claims (4)

(57) [Claims] 1. A heat-sensitive coloring layer mainly comprising a leuco dye and a color developing agent which causes the leuco dye to be colored by heat is provided on a support, and a protective layer mainly comprising a resin and a crosslinking agent is further provided thereon. A thermosensitive recording material comprising a layer, wherein a methylethylketoxime derivative having a group represented by the following structural formula (1) is used as the crosslinking agent. Embedded image 2. A heat-sensitive coloring layer mainly comprising a leuco dye and a developer capable of causing the leuco dye to be colored by heat is provided on a support, and further a resin and a crosslinking agent are mainly comprised thereon. A heat-sensitive recording material comprising a protective layer, wherein bis (β-hydroxyethyl) sulfone represented by the following structural formula (2) is used as the crosslinking agent. Embedded image 3. A heat-sensitive recording, characterized in that a claim 1 or peeling mount via an adhesive layer on a surface opposite to the surface on which is provided a heat-sensitive coloring layer of the support of the heat-sensitive recording material according to 2 Type label sheet. Wherein providing the magnetic recording layer mainly composed of a binder and ferromagnetic on a surface opposite to the surface on which is provided a heat-sensitive coloring layer of the support of the heat-sensitive recording material according to claim 1 or 2 Thermal recording type magnetic ticket paper characterized by the above.