JPS6087092A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance water resistance and plasticizer resistance of a recording paper, by a method wherein a layer of a reaction product of an epihalohydrin with a copolymer of a specified (meth)acrylic acid derivative and an ethylenically unsaturated monomer is used as a protective layer for a thermal color forming layer. CONSTITUTION:An epihalohydrin is brought into reaction with a copolymer comprising a (meth)acrylic acid derivative containing an aminoalkyl group of the formula, wherein R1 is hydrogen or a methyl group, R2 is hydrogen or an alkyl group, R3 is an alkyl group, A is oxygen or amide-nitrogen, and B is an alkylene group, and an ethylenically unsaturated monomer containing an 8-C alkyl group in a molar ratio of 60-15:40-85, in an amount of 70-200mol% to the aminoalkyl groups in the copolymer. A resin thus obtained is applied to the thermal color forming layer comprising a color forming substance, a color developer and a binder in a coating amount of about 0.5-5g/m<2> to provide a coated layer.

Description

[Detailed Description of the Invention] In recent years, the 13 thermal recording method that uses heat has been developed to easily obtain records without requiring any steps such as development and fixing or replenishment materials that are required for conventional print recording methods. Because of its great advantage of being able to be used as a color, its use is expanding more and more.Among these methods, there is a method in which a color-forming substance such as crystal violet lactone and a color developer such as a phenol compound are heated and reacted to form a color. It has been comprehensively evaluated in terms of print clarity, print clarity, etc., and has been put into practical use.

However, for example, cellulose, starch, polyvinyl Afrecol, etc. are often used as binders for the color-forming substance and the color developer, but when the printed recording paper comes into contact with water or plasticizer, the printed characters may disappear or the recording paper may disappear. There remains the problem of water resistance, where the paper becomes sticky. As a countermeasure against this problem, proposals have been made such as providing a protective layer of carboxylic acid-modified polyvinyl alcohol on the recording paper, but if heating and recording are continued for a long period of time using a recording paper with such a layer,
There are disadvantages in that dirt adheres to the thermal head due to friction with the thermal head, and a so-called sticking problem occurs in which the thermal head itself and the thermal recording paper adhere to each other at high temperatures.

The problem of sticking and scum appears to be related to complex factors such as the strength of the resin film used as the protective layer and the glass transition temperature, and no effective solution has yet been proposed.

In addition, regarding the problem of water resistance, methods have been proposed in which the protective layer is made using a crosslinking agent such as formalin or glyoxal as a water resistance agent, or a method using a metal chelate. Since the drying treatment temperature or heat treatment temperature is limited to a relatively low temperature range, water resistance is still not necessarily sufficient.

However, as a result of extensive research in order to resolve these gaps, the present inventors have developed a heat-sensitive recording material having a heat-sensitive color-forming layer consisting of a color-forming substance and a color developer, pine goo, that causes the color-forming substance to develop color when heated. , on the heat-sensitive coloring ring, a kill group, A: oxygen or amide nitrogen, B: an alkylene group containing an aminoalkyl group (meth)
Discovered that the purpose could be achieved by a heat-sensitive recording material provided with a layer of a shrimp halohydrin reaction product, which is a copolymer of an acrylic acid derivative and an ethylenically unsaturated monomer containing an alkyl group having 8 or more carbon atoms, and completed the present J. I came to the conclusion.

By using the above-mentioned resin as a protective layer in "Zero-emitting", it has an excellent effect of preventing sticking and adhesion of residue, and it does not require any treatment with a cross-linking agent or waterproofing agent, and can be easily dried at a low temperature of just drying. Since a sufficient crosslinking reaction occurs during the treatment, a recording paper with good water resistance and plasticizer resistance can be obtained.

The protective layer used in the present invention is a halohydrin reaction of a copolymer of an aminoalkyl group-containing (meth)acrylic acid derivative represented by the above general formula and an alkyl group-containing ethylenically unsaturated monomer having 8 or more carbon atoms. It is a thing.

Examples of aminoalkyl group-containing (meth)acrylic acid derivatives include dimethylaminomethyl (meth)acrylate, dimethylamine ethyl (meth)acrylate, and dimethylaminopropyl! meth)acrylate, dimethylaminomethyl meth)acrylate, dimethylaminopropyl
Shiku meth) acrylate, dimethylaminomethyl meth) acrylate, dipropylaminoprobyl (meth)
Acrylate, monomethylaminomethyl (meth)acrylate, monomethylaminomethyl (meth)acrylate, monoethylaminopropyl (meth)acrylate, monoethylaminopropyl (meth)acrylate, monoethylaminopropyl (meth)acrylate, mono Propynoleaaminoethyl (meth)acrylate, monopropylaminopropyl (meth)acrylate, dimethylaminomethylmeth)acrylamide, dimethylreatrimethacrylreamide, dimethylaminopropylmeth)acryl Reamide, diethylaminoethyl (meth)acrylamide, diethylaminopropyl (meth)acryl reamide, dibrobylreatrimeth)acrylamide, dipropylaminopropyl (meth)acrylamide, etc. It is not necessarily limited. Dimethylaminoethyl methacrylate is preferably used.

The component to be copolymerized with this must be an ethylenically unsaturated monomer having an alkyl group having 8 or more carbon atoms.

Even if it is a monomer that does not contain an allele group such as styrene or a monomer that contains an allele group such as methyl acrylate, if the number of carbon atoms in an allele group is 8 or less, the present invention will not apply. It is difficult to obtain the effects of &I, and only a recording paper with good plasticity resistance, water resistance, etc. can be obtained.

Copolymerization can be carried out by any method such as solution polymerization, emulsion polymerization, suspension polymerization, etc. The copolymerization ratio of the above two components varies somewhat depending on their types and the performance of the intended recording paper, but
Usually, a suitable molar ratio of (meth)acrylic acid derivative: ethylenically unsaturated monoht form is 60-15:40-85.

Those used as the ethylenic inf+1-411 monomer containing an alkyl group having 8 or more carbon atoms are listed below.

Ethylene misuichi ↓ Kazuyuki l Lebon eiffl Alkyl ester octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate I, (°meth)acrylic acid noni t
, decyl (meth)acrylate, dodecyl (meth)acrylate, hexadenyl (meth)acrylate, octadecyl (meth)acrylate, stearyl (meth)acrylate, octyl crotonate, croton Decyl acid, octyl itaconate, decyl itaconate, octyl sorbate, decyl sorbate, dodecyl sorbate, dioctyl maleate, monooctyl maleate, didecyl maleate, didodecyl maleate, monodecyl maleate, monododecyl maleate, etc. .

Chain power! Vinyl levonate ester Vinyl caprate, Vinyl caprate, Hinyl lacrylate, Vinyl persatate, Vinyl balmitate, Vinyl stearate tv'4゜Kouki Z*V Etsuto 2- α-octene, α-decene, α -dodecene, α-hexadecene, α-octadecene, etc.

long chain alkyl vinyl needle octyl vinyl ether, tethyl vinyl ether I;
Dodecyl vinyl ether, tetradecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether! Shi et al.

Long chain alkyl allyl ether octyl allyl ether, decyl allyl ether,
Dodecyl allyl ether, tetradecyl allyl ether, hexadecyl allyl ether, octadecyl allyl ether, etc.

Allyl esters of saturated carboxylic acids, allyl stearate, decyl lafricate, allyl coconut oil fatty acid, allyl octylate, and in the present invention, other monomers that can be copolymerized with these two components are further copolymerized. Polymerization is also possible.

Examples of these monomers are shown below.

Ethylenically unsaturated carboxylic acid alkyl esters methyl crotonate, ethyl crotonate, methyl itaconate, ethyl itaconate, methyl sorbate, ethyl sorbate
And monoalkyl maleate! and dialkyl maleate, alkyl oleate, methyl (meth)acrylate, ethyl (meth)acrylate, (
Examples include propyl meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and butyl (meth)acrylate.

α-olefin Ethylene, propylene, α-hexene, etc.

- earthenware, θfuwaj, luponic acid, 2-(meth)acrylic acid, crotonic acid, (anhydrous) maleic acid, fumaric acid,
Itaconic acid and its alkali metal salts, ammonium salts, etc.

=Full Kill [Yo! and Tamani Otsumi - - propyl vinyl ether, cutyl vinyl ether, hexyl vinyl ether, etc.

Alkyl allyl ether propyl allyl ether, butyl allyl ether, hexyl vinyl ether, etc.

Its contents include vinyl acetate, vinyl propionate, vinyl acetate, (meth)acrylamide, (meth)acrylonitrile, (meth)allyl sulfonate, ethylenically unsaturated sulfonate, styrene, vinyl chloride, allyl acid, etc. It is also possible to use

The copolymer of the present invention needs to be further reacted with shrimp halohydrin, particularly shrimp clohydrin, to quaternize the aminoalkyl group moiety. The reaction is optionally carried out according to known methods. Ebihalohydrin is used in a proportion of 70 to 200 mol % based on the aminoalkyl groups in the copolymer. Of course, this method is not limited to this method, and a monomer which is quaternized by reacting an amino alky group-containing (meth)acrylic acid derivative with shrimp halohydrin, and an ethylenically unsaturated alkyl group-containing monomer having 8 or more carbon atoms. It is also possible to manufacture by copolymerizing monomers.

The resin thus obtained is coated with a thermosensitive coloring layer composed of a coloring substance, a color developer, and a binder. Coating can be done by any means. The concentration of the coating liquid is suitably 1 to 10% by weight in consideration of coatability and the like. Coverage amount is 0.5~
Approximately 5 f /go is preferable.

After coating, the desired coating layer is formed by air drying or mild heat treatment.

Examples of color-forming substances in the present invention include 6,3-bis(p-dimethylaminophenyl)-phtaliFX5,3-
Bis(P-dimethylaminophenyl)-6-dimethylaminophthalide [Crysta! lepaiolet lactone],
6-bis(p-dimethylaminophenyl)-6-diethylreaminophthalide, 6.6-bis(p-dimethylaminophenyl)-6-chlorophthalide, 6-dimethylamino-6-methoxyfluoran, 7-acetamino −
Ro-diethyl rareminofluoran, 6-diethyl raremino-5,7-dimethylfluoran, 6-diethylamino-5,fusimethylfluoran, 6,6-bis-β-methoxyethoxyfluoran, 6. Examples include leuco-deoxygenation of triphenylmethane dyes such as 6-bis-β-cyanoethoxyfluoran.

The color developer may be one that reacts with the color-forming substance when heated and liquefies or vaporizes at room temperature or higher, preferably 70°C or higher, such as pheno-7, P-methylphenol, P-tert-butylene Lephenol, P-
Feni! Lephenol, α-su7tol, β-su7tol, 4,4'-impropylidene diphenol [bisphenol A], 4,4'-secondary butylidene diphenol, 4,4'-cyclohexylidene diphenol Phenol, 4.4'-isopropylidene bis(2-tert-glylidene-11-hexylidene), 4.4'-(+-methyl-11-hexylidene) diphenol, 4.4'-isopropylidene dicatechol, 414 '-benzylidene diphenol, 4,4-impropylidene bis(2-chlorophenol), phenyl-4-hydroxybenzoate, salicylic acid, 6-buenylic acid, 5-methylsalicylic acid, 6,5 -Di-tert-glylsalicylic acid, 1-oxy-2-nabutoe? , m-oxybenzoic acid, 4-oxyphthalic acid, gallic acid, etc., but the color-forming substance and color developer are not limited to these.

In preparing the coating liquid for forming the heat-sensitive coloring layer of ``Kidori'', an aqueous dispersion of the coloring substance and an aqueous dispersion of the color developer are prepared separately, and they are sufficiently stirred to form a fine powder. After pulverization, a uniformly dispersed coating liquid can be obtained simply by mixing and stirring the two liquids. The binder component V is added to at least one of the aqueous dispersion of the color-forming substance and the aqueous dispersion of the color developer. The binder component is suitably 10 to 200% by weight based on the total amount of the color forming substance and color developer. The solid content concentration of the coating liquid is 10 to 10, considering workability etc.
40% by weight]. As a binder, for example, PVA, 1% modified PV containing carboxyl group.
A.Methi? Rese I rerose, carboxymethyl recellulose, starches, latexes, or the same resin as the protective agent of the present invention can be used.

Furthermore, known additives such as thermoplastic substances such as higher fatty acid amides, fillers such as carbonic acid resicum, clay, and titanium dioxide, dispersants, waterproofing agents, and crosslinking agents may also be optionally added.

There is no particular restriction on the paper on which the coating liquid is applied, and any paper can be used.

For coating, any known method such as a roll coater method, an air doctor method, a grade coater method, etc. may be employed. However, the coating amount of the coating liquid is 1 to 1.
It is appropriate to set it to about 20y/a, especially S to 10y/-.

Below, we will further explain the ``1'' that is generated by zero using an example. In the following, "parts" or "%" are based on weight unless otherwise specified.

Example 1 Liquid A and B Liquids A and B were separately ground to an average particle size of 5 using a sand grinder.
Grind until it becomes about μ, then liquid A, liquid B, c, co
A coating liquid was obtained by mixing 350 parts of a 15% aqueous solution of polyvinyl alcohol, which was the same as that used for the can liquid, and 270 parts. The coating solution was applied onto acupuncture paper having a basis weight of 5 oy/rrf in such a manner that the coated area after drying was s, oy/-, and dried.

Furthermore, a 6% aqueous solution of a dimethylaminoethyl nucleate/2-ethylhexyl methacrylate copolymer and shrimp chlorhydrin reactant (copolymerization ratio 35/'65, shrimp hydrin reacts with aminoethyl groups) was added. It was barcoded using a Dixon coater at a ratio of 1.069/G (net) and air-dried to obtain thermal recording paper.

The recording paper was evaluated for sticking, dust adhesion, water resistance, and plasticizer resistance using the following methods.

Regarding sticking and residue adhesion, commercially available 77 Kushimi (Mitsubishi 4fiMr: LFAS-550) f continuous 2
A 0m1 grid pattern was printed and the occurrence of sticking and the degree of adhesion of debris to the thermal head were observed. For water resistance, use the tapered abrasion test on the printed paper as described above! It was measured with an ilI machine. The plasticizer resistance was determined by sandwiching the printed recording paper between soft vinyl chloride sheets, applying a weight of 20 y/- and leaving it for 72 hours, and calculating the color density as a percentage of residual color relative to the original reaction density.

The results are shown in the table.

Control Example 1 An experiment was conducted in the same manner as on the same side using itaconic acid-modified polyvinyl alcohol (denaturation amount 5 mol%, degree of saponification 88 mol%, degree of polymerization +500) instead of the protective layer used in Example 1. went.

The results are also shown in Table 1.

Examples 2 to 4 Experiments were conducted according to Example 1 using protective layers as shown in Table 1. The results are shown in the table.

Claims (1)

[Claims] In a heat-sensitive recording material H having a μ thermochromic layer consisting of a color-forming substance, a color developer and a binder that develop the color-forming physical property when heated, the thermosensitive color-forming layer H contains a methyl group, R2; hydrogen or an alkyl group, R3: An aminoalkyl group-containing (meth)acrylic acid derivative represented by an alkyl group, A: oxygen or amide nitrogen, B: an alkylene group) and an ethylenically unsaturated monocrusate containing an alkyl group having 8 or more carbon atoms and E. 1. A heat-sensitive recording material comprising a layer of a copolymer of shrimp and halohydrin.