JP2566994B2 - Thermosensitive recording material showing color development having absorption in the near infrared region - Google Patents

Description

The present invention relates to a heat-sensitive recording material known as an information recording material. More specifically, it relates to a heat-sensitive recording material that exhibits color development having absorption in the near infrared region.

[Conventional technology and its problems]

In recent years, a method of forming a color on a bar code label known as a so-called POS label by using a thermosensitive recording material and using it for a required purpose has been widely used. This bar code label can be read by a so-called near-infrared reader that uses absorption at 760-800 mμ for reading in addition to devices that use absorption at around 630 mμ. It has become popular recently. However, in the color-developing system conventionally used for the heat-sensitive recording material, almost no compounds exhibit absorption in this region. For example, JP-A-60
No. 226781 (Yamamoto Chemical Synthesis), No. 58-157779 (Kanzaki Paper Co., Ltd.), and the like describe color-forming compounds that absorb in this region, but their actual use is not well understood. As a result, the use of thermal recording paper for POS labels has the drawback that the conventional color development system has a lack of oil resistance.
There is a view that gives a step to the thermal transfer method.

[Means for solving problems]

The inventors have developed a new coloring method that does not depend on the conventional coloring method. (JP-A-57-107882) During the development of the present study, the inventors found that the color image formed by the compound described in the present application had absorption in the near infrared region, and as a result of studies, completed the present invention.

The present invention includes general formula (I) 1) general formula (I) (In the formula, R ₁ , R ₂ and R ₃ are hydrogen atoms or lower alkyl groups, and R ₁ and R ₂ are not hydrogen atoms at the same time.) And a general formula (II). (In the formula, R ₄ is an alkyl group or a cycloalkyl group, X ₁ ,
X ₂ represents a hydrogen atom, an alkylsulfonyl group, an arylsulfonyl group or a benzylsulfonyl group, and the arylsulfonyl group or the benzylsulfonyl group may contain a lower alkyl group, and neither X ₁ nor X ₂ is a hydrogen atom. The present invention relates to a heat-sensitive recording material exhibiting color development having absorption in the near-infrared region, characterized in that the color development component contains a xone derivative represented by (4).

Here, the heat-sensitive recording material is a recording material which transfers a heat energy onto the recording material by an appropriate means to obtain a colored image, and for example, an appropriate melting point depressant, pigment, binder, lubricant, image stabilizer and color former. Each of them is a fine aqueous dispersion, which is mixed and coated and dried on a support to form a color image on the coated surface by an appropriate heating means, or a color-forming component and a color-developing component in the color-forming agent. And k separately, respectively, one is kneaded with a wax-like substance and another auxiliary agent and coated on a support to form an ink sheet, and the other is blended with a pigment, a binder and the like to be coated on a support to form a receiving sheet. A recording material in which the sheets are opposed to each other, and the ink is heated from the back side of the ink sheet to cause melt transfer and color development is exemplified.

The recording material of the present invention relates to a color former in a heat-sensitive recording material, and the paraxylene compound of the general formula (I) which is a color forming component is α, α, α ′, α′-tetrakis (4
-Dimethylaminophenyl) -p-xylene, α, α,
α ′, α′-tetrakis (3- (3-methyl-4-methylaminophenyl) -p-xylene, α, α, α ′,
α'-Tetrakis (4-methylaminophenyl) -p-
Xylene, α, α, α ′, α′-tetrakis (3-methyl-4-ethylaminophenyl) -p-xylene, α,
Examples include α, α ′, α′-tetrakis (4-diethylaminophenyl) -p-xylene and α, α, α ′, α′-tetrakis (4-ethylaminophenyl) -p-xylene.

The quinone compound of the general formula (II), which is a developer component, includes 3-ethylsulfonyl-1,4-quinone-2,5-dicarboxylic acid ethyl, 3-phenylsulfonyl-1,4-quinone-2, Butyl 5-dicarboxylate, isobutyl 3-p-tolylsulfonyl-1,4-quinone-2,5-dicarboxylate,
3- (3 ', 4'-methylphenylsulfonyl-1,4-quinone-2,5-dicarboxylic acid cyclohexyl, 3-benzylsulfonyl-1,4-quinone-2,5-dicarboxylic acid cyclohexyl, 3-α- Naphthylsulfonyl-1,4-quinone-2,5-dicarboxylate butyl, 3- (4'-biphenylylsulfonyl) -1,4-quinone-2,5-dicarboxylate cyclohexyl, 3,6-di-p- Tolylsulfonyl-1,4-quinone-2,5-dicarboxylate isobutyl, 3,6-dibenzylsulfonyl-1,4-quinone-2,5-dicarboxylate cyclohexyl, 3,6-di-p-butylphenylsulfonyl -1,4
-Quinone-2,5-dicarboxylate ethyl or 3-
Examples thereof include (5′-indansulfonyl) -1,4-quinone-2,5-dicarboxylate isobutyl, but the present invention is not limited thereto.

When the compound of the present invention is used in a heat-sensitive recording material, when the absorption in the near infrared region is used, the limit of the amount used is determined by the problem of the sensitivity of the measuring instrument. For example, a TBR6000 machine (manufactured by Token Co., Ltd.) is used as a bar code reader (reading wavelength 780 m
μ), when reading a JAN bar code printed with a bar code printer Logitec-KP123 machine (manufactured by Kanto Electronics Co., Ltd.), paraxylene compound 3.3% or more, quinone in a coating layer with a coating amount of 6 g / m ² The compound is preferably 3.3% or more.

Since the recording material of the present invention produces a color image having strong absorption at 630 mμ in addition to the infrared region, it can be used in the same manner as conventional products both visually and in measurement using an ordinary colorimeter. Further, it is a great feature of the present invention that the color image formed by the compound of the present invention has durability against contamination by oils and fats.

The type of auxiliary component used in the heat-sensitive recording material of the present invention is
As for the amount used, conventionally known ones can be used in exactly the same manner. The melting point depressant is an acid amide type (eg stearic acid amide, N-
Octadecylphthalimide or p-toluenesulfonic acid anilide, etc., ester type (for example, benzoic acid-β-
Naphthyl ester), ether type (for example, benzyl-
All known compounds conventionally used in this field, such as β-naphthyl ether) or hydrocarbons (for example, p-benzyldiphenyl) can be used.

As the pigment, lubricant, etc., kaolin, lime carbonate, magnesium carbonate, carbonate resin type filler, talc and the like which have been conventionally used in this field can be used.

The binder is polyvinyl alcohol (unmodified or modified,
The fully saponified or partially saponified type, acrylamide type water-soluble binder and the like conventionally used in this field can be used. Further, an image stabilizer such as a phenol-based or xanthogenate-based image stabilizer or many ultraviolet absorbers conventionally used in this field can be similarly used. Also when used in a thermal transfer system, the wax, pigment and other auxiliaries used heretofore can be the same as those conventionally used in this field. In addition,
When 2,5-dibenzoylquinone is used as a color developer, the near-infrared portion of the color image is not sufficiently read, which is not suitable for the purpose of the present invention.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to Examples.

Preparation of heat-sensitive recording paper 50 dyes (para-xylene derivative) and 50 quinones, respectively
% Polyvinyl alcohol aqueous solution to make a dispersion with a content of 10%. Make a similar 20% aqueous dispersion of β-naphthylbenzoate and bisphenol S. In addition, prepare a 20% aqueous dispersion of zinc stearate and a 60% aqueous dispersion of lime carbonate. Using this sample, mix the dispersion so that it has the following composition, and use a bar coater on high-quality paper to prepare a dry coating of 6 g.
Coat so that it becomes / m ^2, and dry to make a thermal recording paper.

Composition of blended solution Pigment 19.7 (6.5) Quinone 34.3 (11.6) Bisphenol S 13.9 (4.7) Zinc stearate 13.9 (4.7) β-naphthyl benzoate 55.6 (18.8) Lime carbonate 100.0 (33.8) Polyvinyl alcohol 58.2 (19.7) (Number) Represents the weight ratio of each solid, and the weight in parentheses represents the percentage by weight in the whole solid.) Example 1 A pigment body containing α, α, α ′, α′-tetrakis (4-diethylaminophenyl) -p-xylene, Quinone body 3-
Cyclohexyl benzylsulfonyl-1,4-quinone-2,5-dicarboxylate is used for printing with a barcode printer Lo
JAN code is printed using gitec-KP-123 machine, and TBR-60
When I read it with 00, it was possible to read it sufficiently. The absorption spectrum of the colored product at 400 to 900 mμ was as shown in FIG.

Comparative Example 1 The bar code label paper (commercially available thermal recording paper) attached to the Logitec machine was used to print the JAN code, which was TBR-60.
The 00 machine was completely unreadable.

Examples 2 to 4 The plastids were mixed with α, α, α ', α'-tetrakis (4-dimethylaminophenyl) -p-xylene, α, α, α',
Example 1 except that α'-tetrakis (3-methyl-4-methylaminophenyl) -p-xylene or α, α, α ', α'-tetrakis (4-methylaminophenyl) -p-xylene is used. In the same manner as above, thermal paper was formed and printing was performed. Sufficient reading was possible when reading with the TBR-6000 machine.

Example 5 In Example 1, when α, α, α ′, α′-tetrakis (4-methylaminophenyl) -p-xylene was used for the pigment body, the dye amount was 9.7 and the quinone amount was 17.1. I found that if I read it with a TBR-6000 machine after it was made into paper and printed, it became difficult to read due to the way it was operated, and the limit value was reached.

Examples 6 to 8 3-p-toluenesulfonyl-1,4-as quinone form
Quinone-2,5-dicarboxylate cyclohexyl, 3,6-di-
p-Tolylsulfonyl-1,4-quinone-2,5-dicarboxylate isobutyl or 3,6-dibenzylsulfonyl-1,4-
TBR was printed and printed in the same manner as in Example 1 except that cyclohexyl-2,5-dicarboxylate was used.
-Reading with 6000 machine.

In these examples as well, similar to Example 1, sufficient reading in the near infrared region was possible.

Comparative Example 2 The procedure of Example 1 was repeated except that 2,5-dibenzoylquinone was used as the quinone compound.

Similarly, when reading in the near infrared region, it was difficult to read.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows log (I ₀ / I) in the reflected light of a color-developing substance, where the reflection intensity of the white plate is I ₀ and the reflection intensity of the sample is I with reference to a magnesium oxide white plate. ) Is shown with respect to wavelength.

Claims (1)

(57) [Claims] 1. A general formula (I) (In the formula, R ₁ , R ₂ and R ₃ are hydrogen atoms or lower alkyl groups, and R ₁ and R ₂ are not hydrogen atoms at the same time.) And a general formula (II). (In the formula, R ₄ is an alkyl group or a cycloalkyl group, X ₁ ,
X ₂ represents a hydrogen atom, an alkylsulfonyl group, an arylsulfonyl group or a benzylsulfonyl group, and the arylsulfonyl group or the benzylsulfonyl group may contain a lower alkyl group, and neither X ₁ nor X ₂ is a hydrogen atom. ) A heat-sensitive recording material exhibiting color development having absorption in the near infrared region, characterized in that the color development component comprises a quinone derivative represented by the formula (1).