JPH03227295A - Heat sensitive recording material - Google Patents

Abstract

PURPOSE:To provide excellent crude preservation properties and early heat response and to improve image stability after thermal recording by incorporating alpha-(4-ethoxyphenoxy)acetamide. CONSTITUTION:In a heat sensitive recording material having a recording layer containing diazo compound and coupling component on a support and a protective layer on the recording layer, alpha-(4-ethoxyphenoxy)acetamide is contained in the recording layer. The diazo compound is diazonium salt and can color in coupling reaction with the coupling component and can be decomposed by a light. The diazo compound of main ingredient, the coupling component and, as required, basic substance are used in such a manner that any one, any two or three types are used as core substance or substances of a microcapsule.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat-sensitive recording material, and particularly to a fixable diazo-based heat-sensitive recording material.

(Prior Art) A method of using microcapsules in a diazo thermosensitive recording material is known. Even in the heat-sensitive recording material produced by this microencapsulation method, the storage stability before heat recording and the heat responsiveness during high-speed recording were not sufficient. The present inventors have previously solved the above problems by adding amides to the recording layer of the recording material, and are currently applying for a patent.

However, the image stability after thermal recording was not fully satisfactory, and further improvement was desired.

(Objective of the Invention) Therefore, an object of the present invention is to provide a heat-sensitive recording material which has excellent raw storage stability, quick thermal response (and good image stability after thermal recording).

(Means for Solving the Problems) As a result of intensive research, the present inventors have discovered a heat-sensitive recording material comprising a recording layer containing a diazo compound and a coupling component on a support, and a protective layer on the recording layer. In the recording layer, α
The above object was achieved by using a heat-sensitive recording material characterized by containing -(4-ethoxyphenoxy)acetamide.

In the present invention, providing a protective layer on the recording layer means:
It is particularly preferred for improving runnability, durability, storage stability, and image stability over time after thermal recording. Examples of the protective layer used here include silicon-modified polyvinyl alcohol and colloidal silica, and details regarding these can be found in Japanese Patent Application No. 63169371. In the present invention, it is also possible to provide two or more protective layers of different components.

The present inventors have found that among various amides as additives, α
It has been found that -(4-ethoxyphenoxy)acetamide specifically satisfies the above object.

In the present invention, when a plastic film is used instead of paper as a support, the stability of the image area over time is improved more markedly than in the conventional technology by incorporating the above-mentioned components. It is.

The diazo compound used in the present invention has the formula -i ArN,
X- (wherein, Ar represents an aromatic moiety, N2'' represents a diazonium group, and X- represents an acid anion.)
It is a diazonium salt represented by the following formula, and is a compound that can develop a color by causing a camping reaction with a coupling component, and can be decomposed by light.

The coupling component used in the present invention is one that forms a dye by coupling with a diazo compound (diazonium salt) in a basic atmosphere. 63-
169371, JP-A No. 63-154393, etc., for details.

It is preferable to add a basic substance to the heat-sensitive recording material of the present invention in order to promote color development. Examples of the basic substance include basic substances that are poorly water-soluble or water-insoluble, and substances that generate alkali when heated. used.

Regarding the diazo compound, the camping component, and the basic substance used as necessary, which are the main components used in the present invention, any one of them may be used as the core material of the microcapsule, or two or three of them may be used. Seeds can be used. When two types are contained in the core material of microcapsules, they may be in the same microcapsule or in separate microcapsules. In addition, when containing three types of microcapsules in the core material, it is not possible to simultaneously contain the three types in the same microcapsule, but there are various combinations. Other ingredients not contained in the core material of the microcapsules are used in the heat-sensitive layer outside the microcapsules.

The heat-sensitive recording material of the present invention has high heat sensitivity and can perform low-temperature, high-speed heat recording, and can be fixed by exposing to light to decompose unreacted diazo compounds after heating printing, so it is suitable for various heat-sensitive recordings. It can be used for.

(Example) Examples are shown below, but the present invention is not limited thereto. Note that "parts" indicating the amount added represent "parts by weight."

(Example of the invention) Example 3.45 parts of the following diazo compound and (3:1) adduct of xylylene diisocyanate and trimethylolpropane 1
8 parts were added to a mixed solvent of 24 parts of tricresyl phosphate and 5 parts of ethyl acetate and dissolved.

This diazo compound solution was mixed with polyvinyl alcohol 5.
2 parts dissolved in 58 parts water, 20 parts
The mixture was emulsified and dispersed at ℃ to obtain an emulsion with an average particle size of 2.5 μm. Add 100 parts of water to the obtained emulsion, and add 60 parts of water while stirring.
After 2 hours, a capsule liquid containing a core substance in a diazo compound was obtained.

(Diazo compound) Next, 10 parts of 2-hydroxy-3-naphthoic acid anilide and 10 parts of triphenylguanidine were added to 100 parts of a 5% polyvinyl alcohol aqueous solution, and dispersed in a sand mill for about 24 hours to form a compound with an average particle size of 3μ. A dispersion of the components and triphenylguanidine was obtained.

Furthermore, α-(4-ethoxyphenoxy)acetamide 20
100 parts of 4% polyvinyl alcohol aqueous solution, 10 parts of water
Dispersion was carried out for 2 hours using a paint shaker to which 0 parts were added to obtain a dispersion having an average particle size of 3 μm.

Capsule liquid of diazo compound obtained as above 5
A coupling component, 24 parts of a dispersion of triphenylguanidine, and 28 parts of a dispersion of α-(4-ethoxyphenoxy)acetamide were added to 0 parts to prepare a coating liquid A.

The protective layer coating solution shown below was applied and dried on an 80 μm polyethylene terephthalate film to give a dry weight of 2 g/
rd protective layer was formed, and then coating liquid A was applied thereon to a dry weight of 10 g/rrr and dried at 25° C. for 30 minutes to obtain a heat-sensitive material.

Silica-modified polyvinyl alcohol (PVA R2105 manufactured by Kura LzO1) 1 part (solid content) Colloidal silica (Snowtex 30 manufactured by Nissan Chemical ■) 1.5 parts (solid content) Zinc stearate (Hydrin manufactured by Middle East Oil Co., Ltd.) Z-7) 0.02 part (solid content) Paraffin wax (Hydrin P-7 manufactured by Middle East Oil Co., Ltd.) 0.02 part (solid content) (test method) Thermal recording was performed using a Hifax 700 (manufactured by Hitachi, Ltd.), and then the entire surface was exposed and fixed using Ricopy Super Dry 100 (manufactured by Ricoh ■). The yellow density of the background was also measured.

Next, in order to investigate the decrease in optical density of the colored part due to long-term storage after thermal recording, the recorded image of the thermal recording material was
The sample was stored in a dark place at ℃ for 16 hours, and the surface shape of the recorded image was observed after performing a forced deterioration test.

As a result, a clear blue image was obtained in the printed area, the image density was >1.2, the background yellowing density was <0.10, and no change was observed in the surface shape of the image area after the forced deterioration test. , showed excellent properties.

Comparative Example 1 A heat-sensitive material was obtained in the same manner as in the example except that α-(4-methoxyphenoxy)acetamide was used instead of α-(4-ethoxyphenoxy)acetamide in the example. When the recording material was tested in the same manner as in the examples, it was found that although the image density and background yellowing density were the same as in the examples, the surface shape of the image area deteriorated over time.

Comparative Example 2 A heat-sensitive material was obtained and tested in the same manner as in the example except that the protective layer in the example was used. The image density and background yellowing density were the same as in the example, but It was found that the surface shape of the image area had significantly deteriorated.

Claims (1)

[Claims] In a heat-sensitive recording material in which a recording layer containing a diazo compound and a coupling component is provided on a support and a protective layer is provided on the recording layer, α-(4-ethoxyphenoxy) is added to the recording layer.
A heat-sensitive recording material characterized by containing acetamide.