JPS5811191A - Thermo-sensitive recording material - Google Patents

Abstract

PURPOSE:To obtain the thermo-sensitive recording material, foundation thereof hardly forms a color and head matching property thereof is improved remarkably, by shaping a thermo-sensitive color-forming layer, which is acquired by making fillers coated with silicon resin or a silane coupling agent contain in leuco dyestuffs and an acidic substance for forming the color when heating, onto a substrate. CONSTITUTION:Normally, the fillers coated with the silicon resin or the silane coupling agent are made contain in the thermo-sensitive color-forming layer containing the colorless or light-colored leuco dyestuffs and the acidic substance, which can color-form the dyestuffs when heating, as principal ingredients. The thermo-sensitive color-forming layer obtained is shaped onto the substrate, and the aimed thermo-sensitive recording material is acquired. The fillers used are the fillers of the thermo-sensitive color-forming layer, and fines (grain size is 0.1-30mu, preferably, 0.5-10mu) such as calcium carbonate available for improving various performance, such as the matching property of a thermal head and a thermal pen, writing property, the whiteness of the foundation of the recording material, etc. are employed. The fillers are coated with the silicon resin or the silane coupling agent and used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive recording material, more specifically, a heat-sensitive coloring layer containing as a main component a usually colorless or light-colored leuco dye and an acidic substance capable of coloring the leuco dye when heated. The present invention relates to an improvement in a heat-sensitive recording material having the structure formed above.

Recently, various recording materials have been researched and developed and put into practical use in the information recording field, in response to social demands such as diversification and increase in information, resource conservation, and pollution-free technology.Among them, thermal recording materials are (1) A colored image is recorded simply by heating, eliminating the need for a complicated development process. (2) It can be produced using a relatively simple and compact device, and the resulting recording material is easy to handle. (3) paper is often used as the support;
In this case, there are several advantages such as not only the cost of the support is low, but also the feel of the obtained recording material is similar to that of plain paper.
It is widely used in the fields of computer output, printers such as calculators, recorders for medical measurement, low and high speed facsimiles, automatic ticket vending machines, thermal copying, etc.

The above-mentioned heat-sensitive recording material is produced by coating a support such as ordinary paper, synthetic paper, or synthetic resin film with a heat-sensitive coloring layer forming liquid containing a coloring component that can cause a coloring reaction when heated, and drying it. Furthermore, a colored image is recorded on the heat-sensitive recording material thus obtained by heating it with a thermal pen or a thermal head. Conventional examples of such heat-sensitive recording materials include, for example, the heat-sensitive recording materials disclosed in Japanese Patent Publication No. 43-4160 or Japanese Patent Publication No. 45-14039; Responsiveness was low, and sufficient color density could not be obtained during high-speed recording, and non-printed areas developed color (called background coloration), greatly impairing the clarity of colored images.

However, when recording by heating a heat-sensitive recording material, components in the heat-sensitive color forming layer may melt and stick to the thermal head or pen (resistance adhering), causing a sticking phenomenon that causes problems in paper feeding. Objects may be transferred to the recording material and cause trailing. These properties are called head matching properties, and are extremely important when considering the quality of heat-sensitive recording materials.

As a method for improving the above-mentioned drawbacks of conventional heat-sensitive recording materials, for example, Japanese Patent Application Laid-Open No. 48-19231 discloses a method of incorporating waxes with a melting point of 40 to 100° C. into a heat-sensitive coloring layer to improve thermal responsiveness. In addition, in Japanese Patent Publication No. 51-27599, a method is described in which a fatty acid amide and a petroleum wax are used together in a heat-sensitive coloring layer to improve heat responsiveness and residue adhesion. This is not a sufficient improvement method, and further improvements are desired, especially in terms of thermal response during high-speed recording, bleeding (color development due to residual heat in non-printed areas), and head matching properties such as dregs adhesion, sticking noise, and sticking.

The inventors of the present invention have conducted extensive research to overcome the above-mentioned drawbacks, and have found that the coloring of the background is improved by including a filler coated with a silicone resin or a silane coupling agent as a component in the heat-sensitive coloring layer. It has been discovered that a heat-sensitive recording material that is smooth and has significantly improved head matching properties can be obtained, and the present invention has been completed. That is, according to the present invention, in a heat-sensitive recording material having a structure in which a heat-sensitive color-forming layer containing a leuco dye and an acidic substance that causes the leuco dye to develop color when heated as a main component is formed on a support, in the heat-sensitive color-forming layer, Provided is a heat-sensitive recording material characterized in that it contains a filler coated with a silicone resin or a silane coupling agent.

The filler applied in the present invention is a filler for a thermosensitive coloring layer, and is a fine powder used to improve various performances such as matching properties of thermal heads and pens, writing properties, and whiteness of the background of recording materials. , the particle size is 0.1-30μ, preferably 0.5
~10μ is used.

Specific examples of fillers include inorganic fillers such as calcium carbonate, silica, magnesium hydroxide, aluminum hydroxide, clay, talc, alumina, titanium oxide, and barium sulfate, urea-formalin resin, styrene-methacrylic acid copolymer, and phenol. Examples include organic fillers such as resins.

Among these, remarkable effects can be obtained when calcium carbonate is used as a filler.

In the present invention, the filler described above is used after being coated with a silicone resin or a silane coupling agent. Silicone resin has a three-dimensional network structure with siloxane bonds as the core, while silane coupling agents
These are reactive silane compounds such as vinyltrimethoxysilane, aminosilane, epoxysilane, methacryloxysilane, mercagto-7-lane, and the like. The thickness of the coverage of silicone resin or silane coupling agent is usually 0.01-5
= ~1μ, preferably 0.02-0.5μ.

In the heat-sensitive coloring layer, the amount of silicone resin or silane coupling agent used is preferably 1 to 50% by weight relative to the filler. A typical method for providing a surface coating layer of silicone resin or silane coupling agent on a filler is to put the pigment in a spray dryer, spray a silane coupling agent solution dissolved in a solvent, dry it, and coat the surface. This is a typical method.

Calcium carbonate having a surface coating layer of carbon dioxide, silicone resin, or silane coupling agent is commercially available, and any of them can be used in the present invention. The filler whose surface is coated with a silicone resin or a silane coupling agent is usually 1 to 20 parts by weight, preferably 2 to 1 part by weight, per 1 part by weight of the leuco dye used.
0 parts by weight are used.

The heat-sensitive recording material of the present invention contains the silicone-processed filler, a leuco dye, an acidic substance, a binder, and, if necessary, a heat sensitivity increaser (for example, higher fatty acid amide), and an antifoaming agent. A thermosensitive coloring layer forming solution containing conventional components such as agents, penetrants, etc., is applied to paper, for example.
It is manufactured by applying it to the surface of a support such as synthetic paper and drying it.

Specific examples of the leuco dye, acidic substance, and binder are shown below.

(5) Leuco dye As the leuco dye, leuco forms of the various colorless or light-colored dyes shown below are usually used.

(a) Leuco compound sea urchin of triphenylmethane dye represented by the following general formula (where Rx, Ry and Rz are hydrogen, hydroxyl group, halogen, alkyl group, nitro group, amine group, dialkylamide 7 group, monoalkyl and allyl group.) Specific examples of the above leuco compounds are as follows.

3.3-bis(p-dimethylaminophenyl)-phthalide 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone) 3.3-bis(p-dimethylamino phenyl)-6-dibutylaminophenyl 3.3-bis(p-dimethylaminophenyl)-6~chlorophthalide 3.3-bis(p-dibutylaminophenyl)phthalide←) Leuco fluoran dye represented by the following general formula Compound: In the formula, R, x, Ry and RZ are the same as in the above (a).

Specific examples of the above compounds are as follows.

3-Cyclohexylamino-6-chlorofluorane 3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluoran 3-dimethylamino-5,7-dimethylfluoran 3-diethylamino-7-methylfluoran 3-diethylamine-7,8-benzfluoran Ce Leuco compound of fluoran dye: 3-Diethylamino-6-methyl-7-chlorofluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 2-(N-(3'-toIJfluoromethylphenyl)amine)-6-dinityl Aminofluorane 9-2-(3,6-bis(diethylamino)-9-(0-chloroanilino)xanthylbenzoic acid lactam) ←) Lactone compound represented by the following general formula: (Xrin, where R1 and R2 represents hydrogen, a lower alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted phenyl group, a cyanoethyl group, or a β-halogenated ethyl group, or R1 and R2 combine to form +CH2+-
4, + CH2 beauty or +CH2 false 0+CH2-), , R8 and R2 represent hydrogen, a lower alkyl group, an alkyl group, an amino group or a phenyl group, 'fL3
Any one of and R4 is hydrogen; X represents hydrogen, halogen, a lower alkyl group or a lower alkoxyl group, and n represents 0 or an integer of 1 to 4.

Specific examples of the above compounds are as follows.

3-(2'-hydroxy-41-dimethylaminophenyl)-3-(2'-methoxy-51-chlorophenyl)
Phthalide 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-51-nitrophenyl)
Phthalide 3-(,2'-hydroxy-4'-diethylaminophenyl)-3-(2'nimethoxy-5'-methylphenyl)phthalide 3-(2'-methoxy-4'-dimethylaminophenyl)-3-( 2'-Hydroxy-4'-chloro-51-methylphenyl)phthalide.

However, acidic substances The following various acidic substances can be used as acidic substances that react with the above-mentioned leuco dye when heated to cause it to develop color.

(a) Organic and inorganic acids boric acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, benzoic acid, stearic acid, gallic acid, salicylic acid, 1-hydroxy-2-naphthoic acid, 0-hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxy-
p-Toluic acid.

(b) Phenolic substances 3.5-xylenol, thymol, p-1crt-butylphenol, 4-hydroxyphenoxide, methyl-
4-Hydroxybenzoate, 4-hydroxyacetophenone, α-su7tol, β-naphthol, catechol, resorcinol, hydroquinone, 4-tert-octyl/
-/l/, 2,2'-dihydroxydiphenyl, 2゜21-methylenebis(4-methyl-6-ter
t-butylphenol), 2.2-bis(4-hydroxyphenyl)furopane, 4.4-(:/7' robylidene bis(2-te-hundred-butylphenol), 4+'
5eC-butylidene diphenol, pyrogallol, phloroglucin, phloroglucin carboxylic acid.

0 Binder The following various binders can be used to bond and support the thermosensitive coloring layer on the support.

Water-soluble polymers such as polyhinyl alcohol, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch, gelatin, etc.
Alternatively, an aqueous dispersion of polystyrene, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, etc. can be used as the binder.

Next, the present invention will be explained in detail using examples.

13 Example 1 Aqueous dispersions A, B, C, and D having the following compositions were prepared.

[Dispersion A]

2-(N-(3'-)IJfluoromethylphenyl)
amine)-6-dinithylaminofluorane 150 parts by weight 5% polyvinyl alcohol aqueous solution 15
0 (Using Poval 117 manufactured by Kuraray Co., Ltd.) Water
200
# [Dispersion B] 2, 2-his(p-hydroxyphenyl)furopane 1
20 parts by weight 5% polyvinyl alcohol aqueous solution 120 rr ((
(Using Poval 117 manufactured by Kuraray Co., Ltd.) Water
160 [Dispersion C] Stearic acid amide 150 parts by weight 5% methylcellulose aqueous solution 150 Water
200 〃 1
4- [Dispersion 1] Calcium carbonate surface-treated with silicone resin (ST powder manufactured by Shiraishi Kogyo Co., Ltd.) 150 parts by weight 5%
Methylcellulose aqueous solution 150 Water
200〃10 parts by weight to the aqueous dispersion prepared as above, B
20 parts by weight of, 10 parts by weight of C, 20 parts by weight of D, and 20 parts by weight of 20% polyvinyl alcohol aqueous solution, 0
Five types were mixed uniformly to obtain a thermosensitive coloring layer forming liquid. The thermosensitive coloring layer forming liquid was coated on the surface of commercially available high-quality paper (53 g/m') and dried to obtain a recording paper with an adhesion amount of 6.5 g/m' (solid content), and the Bekk smoothness was The desired heat-sensitive recording paper was produced by calendering for 500 to 600 seconds.

Example 2 In place of the thermosensitive coloring layer forming liquid of Example 1, 40 parts by weight of the aqueous dispersion prepared in Example 1, 10 parts by weight of A, 20 parts by weight of B, 10 parts by weight of C, and A thermosensitive recording paper was produced in exactly the same manner as in Example 1, except that a thermosensitive coloring layer forming liquid obtained by mixing 5 types of 20% polyvinyl alcohol aqueous solution (20 parts by weight) was used.

Example 3 An aqueous dispersion F having the following composition was prepared.

[Dispersion liquid F]

Calcium carbonate surface treated with silane coupling agent (
150 parts by weight 5% methyl cellulose aqueous solution 150 Water
200
〃20 parts by weight of the above aqueous dispersion F, 10 parts by weight, 20 parts by weight, 10 parts by weight of the aqueous dispersions A, B, and C prepared in Example 1, and 20 parts by weight of a 20% polyvinyl alcohol aqueous solution, A thermosensitive recording paper was obtained in exactly the same manner as in Example 1, except that the thermosensitive coloring layer forming liquid obtained by mixing 05 types was used instead of the thermosensitive coloring layer forming liquid of Example 1.

Example 4 A thermosensitive recording paper was obtained in exactly the same manner as in Example 3 except that 40 parts by weight of aqueous dispersion F was used instead of 20 parts by weight of aqueous dispersion F in Example 3.

Comparative example 1 Aqueous dispersion E having the following composition was prepared.

[Dispersion E]

Calcium carbonate 150 parts by weight 5% methylcellulose water fa'Fl 15o tt
water 2
00 A thermosensitive coloring layer forming liquid was obtained in exactly the same manner as in Example 1, except that 20 parts by weight of the above aqueous dispersion E was used instead of 20 parts by weight of the aqueous dispersion in Example 1,
Then, a thermosensitive recording paper was produced using this in the same manner as in Example 1.

Comparative Example 2 Carbonic acid obtained by mixing 10 parts by weight, 20 parts by weight, and 10 parts by weight of the aqueous dispersions A, B, and C prepared in Example 1 and 20 parts by weight of 20% polyvinyl alcohol aqueous solution and Type 04. A thermosensitive recording paper was produced in exactly the same manner as in Example 1, except that a calcium-free thermosensitive coloring layer forming liquid was used in place of the thermosensitive coloring layer forming liquid in Example 1.

The thermal recording papers of Examples 1 to 4 and 17-Comparative Examples 1 to 2 produced as described above were subjected to a thermal facsimile machine having a thin film thermal head (Oki Electric Industry Co., Ltd. (a):
0KIFAX-7100). Table 1 shows the measurement results of head matching properties (sticking, sticking sound, and debris adhesion), color image density, and background density during recording. From the table, it can be seen that the heat-sensitive recording material of the present invention using a silicone-treated filler has excellent head matching properties, high color image density, and low background density.
It is determined that a clear colored image can be provided. The color image density and background density were measured using a Macbeth Densitometer Model RD-514 manufactured by Macbeth Company.

,,, /”'/' 18- Table-1 Banding property; Sticking, stick sound and debris adhesion are 5
Evaluation was performed using a graded evaluation method.

◎ Not at all ○ There is no way ○Δ There is some (no problem in practice) Δ Too many (slightly problematic in practice) × Very many (practical problems) Patent applicant Ricoh Co., Ltd. Agent: Patent Attorney Toshiaki Ikeura 19 -

Claims (1)

[Claims] (1) In a heat-sensitive recording material having a structure in which a heat-sensitive coloring layer containing a leuco dye and an acidic substance that causes the leuco dye to develop color when heated is formed on a support, silicone resin or silane is contained in the heat-sensitive coloring layer. A heat-sensitive recording material characterized by containing a filler coated with a coupling agent.