JPS6221594A - Transfer medium for thermal recording - Google Patents

Abstract

PURPOSE:To obtain the titled medium excellent in uniformity of transferred characters or images in long-time continuous use thereof and in clearness of print or the like, by incorporating a resin having a number average molecular weight of not more than 30,000 and a pigment into an ink layer, in a transfer medium for thermal recording which has an ink layer on a base. CONSTITUTION:The transfer medium for thermal recording comprises an ink layer on a base, the ink layer comprising a resin having a number average molecular weight of not more than 30,000 and a pigment. The resin may be a polyolefin, a copolymer thereof, a vinyl chloride copolymer or the like. Pigments separated on the basis of color such as red, yellow and blue are used mainly for obtaining color characters and images. The thickness of the ink layer is 0.5-20mum, preferably, about 0.8-10mum. If the thickness is more than 20mum, problems such as low transferring sensitivity and unclear print are generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Background of the Invention Technical Field The present invention relates to a transfer medium for thermal recording.
For more information, please refer to fax, computer printer,
This invention relates to the improvement of the ink layer of thermal recording transfer media for output printers of office automation equipment, various recorders, etc.

Prior Art and its Problems In recent years, with the diversification of information, the development of thermal recording transfer media for use in facsimiles, computer printers, output printers for OA equipment, various recorders, etc. has been actively promoted.

Such thermal recording has the advantages that colored characters and images can be easily obtained by heating means, that a complicated developing process is not required, and that the hardware used is a relatively compact and simple device.

BACKGROUND ART Conventionally, so-called thermal paper of dye coloring type or metal compound type is known as a commonly used thermal recording medium. However, recently, there has been a strong demand for image reliability, and a recording method using a thermal recording transfer medium to obtain a transferred character image on so-called plain paper is becoming mainstream.

Various reports have been made regarding transfer media for thermal recording used in such recording methods, which are usually formed by depositing an ink layer containing a colorant and a resin on a substrate.
Improvements in printing clarity and storage stability (Unexamined Japanese Patent Publication No. 53
-81246, 55-39381, 58-
(No. 199195), improvement regarding wear resistance (Unexamined Japanese Patent Publication No. 199195)
8-201693), print clarity, adhesion to the material,
There are improvements regarding transferability (Japanese Patent Application Laid-Open No. 59-29196).

However, in practical use, the uniformity of transferred characters and images during continuous use over a long period of time is not yet satisfactory.

II. OBJECTS OF THE INVENTION The object of the present invention is to provide a heat-sensitive recording transfer that has excellent uniformity of transferred character Φ images during long-term continuous use, and also has excellent print clarity, storage stability, abrasion resistance, and transferability. The goal is to provide a medium.

■Disclosure of invention Such object is achieved by the present invention in Section F.

That is, the present invention provides a thermal recording transfer medium having an ink layer on a substrate 1-, in which the ink layer has a number average molecular weight of M300.
The present invention is a transfer medium for heat-sensitive recording, characterized in that it contains a resin of 0.00 or less and a pigment.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The transfer medium C for thermal recording of the present invention will hereinafter be simply referred to as a transfer medium. ) has an ink layer on the substrate. The ink layer contains a resin with a number average molecular weight of 30,000 or less and a pigment.

There are no particular restrictions on the resin used in the present invention, but
Among them, the resins shown below are preferred.

i) Polyolefin polyethylene, polypropylene, poly4-methylpentene-1, etc.

ii) Polyolefin copolymers such as ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, ethylene-acrylic acid copolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, Ethylene-maleic anhydride copolymer, ethylene propylene terpolymer (EPT), etc.

In this case, the polymerization ratio of the comonomers can be set arbitrarily.

111) Vinyl chloride copolymer, for example, vinyl acetate-vinyl chloride copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-maleic anhydride copolymer, acrylic ester or methacrylic ester and vinyl chloride Copolymers, acrylonitrile-vinyl chloride copolymers, vinyl chloride, ether copolymers, ethylene or propylene-vinyl chloride copolymers, ethylene-vinyl acetate copolymers grafted with vinyl chloride, etc.

In this case, the copolymerization ratio can be arbitrary.

iv) Vinylidene chloride copolymer Vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-vinyl chloride-acrylonitrile copolymer, vinylidene chloride-butadiene-vinyl halide copolymer, etc.

In this case, the copolymerization ratio can be arbitrary.

V) Polystyrene vi) Styrene copolymer, for example, styrene-acrylonitrile copolymer (AS
resin), styrene-acrylonitrile-butadiene copolymer (ABS resin), styrene-maleic anhydride copolymer (SM'A resin), styrene-acrylic acid copolymer, styrene-butadiene copolymer, styrene-butadiene copolymer (SDR), styrene-111 vinylidene ζ
polymers, styrene-methyl methacrylate copolymers, etc.

In this case, the copolymerization ratio can be arbitrary.

vll) Styrene type polymers such as α-methylstyrene, p-methylstyrene, 2
, 5-dichlorostyrene, α.

β-vinylnaphthalene, α-vinylpyridine, acenaphthene, vinylanthracene, or copolymers thereof, such as copolymers of α-methylstyrene and methacrylic ester.

viii) Coumarone-indene resin Coumarone-indene-styrene copolymer.

ix) Terpene resin or picolite For example, terpene resin which is a polymer of limonene obtained from α-pinene, or picolite obtained from β-pinene.

X) Acrylic resin Particularly preferred are those containing an atomic group represented by the following formula.

Formula R10 CH-C- -OR2g In the L notation, R10 represents a hydrogen atom or an alkyl group, and R211 represents a substituted or unsubstituted alkyl group.

In this case, in the L notation, R10 is preferably a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, particularly a hydrogen atom or a methyl group. In addition, R20 is
Although it may be a substituted or unsubstituted argyl group, it is preferable that the alkyl group has 1 to 8 carbon atoms,
Furthermore, when R211 is a substituted alkyl group, the substituent substituting the alkyl group is preferably a hydroxyl group, a halogen atom, or an amino group (particularly a dialkylamino group).

Such an atomic group represented by the -1- notation may form a copolymer with other repeating atomic groups to constitute various acrylic resins, but usually, the atomic group represented by the -1- notation is An acrylic resin is formed by forming a homopolymer or copolymer having one or more of the groups as repeating units.

xi) Polyacrylonitrile xii) Acrylonitrile copolymer, for example, acrylonitrile-vinyl acetate copolymer, acrylonitrile-vinyl chloride copolymer, acrylonitrile-styrene octapolymer, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-vinylpyridine copolymer, acrylonitrile-methyl methacrylate copolymer,
Acrylonitrile-butadiene copolymer, acrylonitrile-butyl acrylate copolymer, etc.

In this case, the copolymerization ratio can be arbitrary.

xiii) Diacetone acrylamide polymer A diacetone acrylamide polymer obtained by reacting acrylonitrile with acetone.

xiv) Polyvinyl acetate X ma) Vinyl acetate copolymers, such as copolymers with acrylic esters, vinyl ethers, ethylene, vinyl chloride, etc.

The copolymerization ratio may be arbitrary.

xvi) Polyvinyl ethers such as polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl butyl ether, etc.

xvii) Polyamide In this case, polyamides include ordinary homonylons such as nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 9, nylon 11, nylon 12, and nylon 13, as well as nylon 6. /6-6/6-1
0, nylon 6/6-6/12. Nylon 6/6-6/
Polymers such as No. 11 or modified nylon may be used as the case may be.

xviii) Polyesters For example, various dibasic acids such as aliphatic dibasic acids such as oxalic acid, succinic acid, maleic acid, adipic acid, sebastenic acid, or aromatic dibasic acids such as isophthalic acid and terephthalic acid, and ethylene glycol. Condensates and co-condensates with glycols such as , tetramethylene glycol and hexamethylene glycol are suitable.

Among these, condensates of aliphatic dibasic acids and glycols and cocondensates of glycols and aliphatic dibasic acids are particularly suitable.

Furthermore, for example, a modified gliptal resin, which is a condensation product of phthalic anhydride and glycerin, is esterified and modified with a fatty acid, a natural resin, etc., and the like can also be suitably used.

m1x) Polyvinyl acetal resin Both polyvinyl formal and polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol are preferably used.

In this case, the degree of 7-cetalization of the polyvinyl acetal resin can be arbitrary.

xx) Polyurethane resin Thermoplastic polyurethane resin with urethane bonds.

Particularly suitable are polyurethane resins obtained by condensation of glycols and diincyanates, particularly polyurethane resins obtained by condensation of alkylene glycol and alkylene diisocyanate.

xxi) Polyether styrene formalin resin, ring-opening polymer of cyclic acetal, polyethylene oxide and glycol, polypropylene oxide and glycol, propylene oxide-ethylene oxide copolymer, polyphenylene oxide, etc.

Xtm ii) Cellulose derivatives For example, various esters and ethers of cellulose, such as nitrocellulose, acetylcellulose, ethylcellulose, acetylbutylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylhydroxyethylcellulose, and mixtures thereof.

1.1 ii) Polycarbonates such as polydioxydiphenylmethane carbonate,
Various polycarbonates such as dioxydiphenylpropane carbonate.

Ftima) Ionomer Na such as methacrylic acid and acrylic acid.

Li, Zn, Mg salts, etc.

! Tomima) Ketone resin: For example, a condensate of a cyclic ketone such as cyclohexanone or acetophenone and formaldehyde.

! ! i) Xylene resin, such as 1m-xylene or a condensate of mesitylene and formalin, or various modified products thereof, such as rosin modification.

(ii) Petroleum resins C5 type, C9 type, C5-c9 copolymer type, dicyclopentadiene type, or copolymers or modified products thereof.

In the present invention, the resins i) to (iii) above may be used alone or in combination of two or more.

The number average molecular weight of these resins is 3000 as mentioned above.
It is preferably 0 or less, particularly 300 to 1oooo.

When this number average molecular weight exceeds 30,000, transfer sensitivity
Print uniformity becomes extremely poor.

In addition to such a resin, the ink layer of the present invention further contains a pigment.

Such pigments include azo dyes, anthraquinones, indigoids, soluble dyes, sulfide, carbonium, phthalocyanine, quinoneimine, cyanine, nitroso, nitro, stilbene, quinoline, and pyrazolone pigments. , 1:2 type metal complex salts, benzoquinones, naphthoquinones, etc., but in the present invention, they are mainly contained to obtain color characters and images.

Therefore, it is preferable to use pigments that have been separated into the colored threads shown below.

(1) Red (magenta) Azo type, dyed with lake, fused polycyclic (anthraquinone, thioindigo, perinone, perylene, quinacridone, isoindolinone) alizarin lake, daylight fluorescence, specifically pigment red 57.57: 1.57:2
(Color index) For example, Br1lliant C
armin 8B, BB Tourner (Daime Seika) Sy+5uler Br1lliant Carmi
ne 8B (Dainippon Ink) Sanyo Br1lliant Carmine E
IB, 88N (deuterochrome) Sanyo Fast R
ed FOR (deuterochrome) Sanyo Lithol
Rubin BKN (deuterochrome) Graph
tol Rubin BP (Sand)
Rubin Taner 4B, 4BA
(I CI ) Vulcafor C1aret Y
There are pigments such as (I CI ).

(2) Yellow Azo type, dyed with lake, condensed polycyclic (anthraquinone, isoindolinone, quinophthalone, isoindoline, nitroso, metal complex salt, azomethine, daylight fluorescence, specifically pigment yellow 13 (color Index) For example, Benzidine Yellow 2GR (Daimeki Seika) Symuier Fast Yellow GRF
(Dainippon Ink) Sanyo Light Fa
st Benzidine Yellow R (deuterochrome) Graphol Yellow GRBL
(Sand) Nonolite Yellow GL
(ICI) Vynamon Yellow
There are pigments such as ow GRE (I CI ).

(3) Blue (cyan) Azo type, phthalocyanine, lake dyeing, fused polycyclic (anthraquinone), alkali blue, daylight fluorescence, specifically pigment blue 15 (color index) For example, Lionol Blue FG 7351
(Toyo Ink) Lionol Blue FG 739
3G (Toyo Ink) Graphol Bl
ue 2GLS (Sand) Monastr
al Fast Blue BG (I CI
) and other pigments.

(4) Black Aniline black, carbon black The pigment may be inorganic as well as organic.

The average particle diameter of the pigment used is about 0.005 to 10 μm, more preferably 0.01 to 4 μm.

Such a pigment is contained in an amount of 1 to 200 parts by weight, more preferably 3 to 70 parts by weight, based on 100 parts by weight of the resin described above.

Furthermore, in the ink layer, in addition to these pigments and resins having a number average molecular weight of 30,000 or less, various waxes, various pigments, various oils, various ceramic particles,
Various polymer dispersants, plasticizers, stabilizers, etc. may be added in an amount of about 0.1-Zoo parts by weight per 100 parts by weight of the resin.

The thickness of the ink layer formed from the composition as described above is between 0.5 and 20 g, more preferably between 0.8 and 10 g.
It is said to be about the same level as a dozen meal. If the thickness exceeds 20p or m, there will be problems such as decreased transfer sensitivity and loss of print clarity, and if it is less than 0.5IL, there will be problems such as insufficient print density. arise.

The ink layer having such a thickness can be formed by various known layer forming methods, such as a melting method using hot melt, gravure coating, roll coating, air knife coating, dip coating, etc. A solution method such as spinner coating may be used.

Substrates on which such an ink layer is formed include polyethylene terephthalate (PET), polyethylene, polycarbonate, nylon, polyamide, polyimide, polyphenylene sulfide, polysulfone, fully aromatic polyester, polyether ether ketone, and polyether sulfide. It is preferable to use resin films such as polyetherimide and polyetherimide.

The thickness of such a substrate is not particularly limited, but is usually about 0.8 to 20 μm.

Further, the shape of the base body is not particularly limited, and various shapes are possible.

Further, the medium of the present invention may be used for a single color or for multiple colors, and its structure may be one of various known media.

A top coat layer containing various waxes or the like may be provided on the ink layer of the present invention.

Furthermore, on the back side of the base (without an ink layer), a back coat layer containing various metal layers such as A, silicone or fluorine resin, each sleeve tip or electron beam curing resin, various thermosetting resins, etc. It may be provided.

■Specific effects of the invention In the thermal recording transfer medium of the present invention, plain paper is placed on the ink layer -F of the medium, and the ink layer is heated by the thermal head that contacts the back surface of the substrate of the medium and moves relatively. Plain paper
- is to be transferred to. That is, the head is heated by applying a current to the thermal head according to the signal for an arbitrary period of time. The heat transmitted through the substrate melts or sublimates the ink layer, and the melted or sublimated ink layer adheres to plain paper. When the medium and plain paper are gradually peeled off, the ink layer leaves the substrate and becomes completely normal. transferred onto paper. In this way, characters and images are printed on plain paper-L.

The transfer medium for thermal recording in the present invention has an ink layer on the substrate 1-, and this ink layer contains a resin having a number average molecular weight of 30,000 or less and a pigment.

Therefore, it has excellent uniformity of transferred characters and images during continuous use, and also has excellent effects on print clarity, storage stability, abrasion resistance, and transferability.

(2) Specific Examples of the Invention Below, specific examples of the present invention will be shown and the present invention will be explained in more detail.

(Example 1) 2. Polyethylene terephthalate (PET) with opLm thickness
) Using a resin film as a base, various ink layers having the compositions shown below were formed on the -H using a gravure coating method using a predetermined solvent to prepare samples. Note that the numerical value in parentheses is the number average molecular weight of the resin.

Ketone Resin Oligomer (1200) 6 Brilliant Carmine 6B Toner 1 Koutsu L1 Kougei”
Part by weight Polyamide copolymer oligomer
5Lionol Blue FG? 393G
IL Niro 11ji Part by Weight Polyurethane Oligomer 7 (16'0O) Sanyo Lithol Rubin BKN
1 Hikari fl. Weight part petroleum resin (1300) 6Symui
er Fast Yellow GRF 1
(Comparison) The oligomer resin having a number average molecular weight of 1,200 used in the ink layer composition 1 was replaced with an acrylic polymer having a number average molecular weight of 110,000.

Other than that, the composition was the same as the ink layer composition 1.

The characteristics shown below were measured for the various samples thus produced.

(1) Uniformity of transfer density The sample described in 2 was used as a transfer medium for thermal recording, the thermal head recording power was 0.8 W/dot, and the pulse II was 0.
, 5 rnsec, 1 m of continuous transfer was performed on plain paper. The minimum value with respect to the maximum value of these transfer densities was expressed in % and was taken as the value of the uniformity of the transfer densities.

The transfer density was measured using Sakura Microdensitometer PDN.
-5 (manufactured by Konishiroku Photo Industry Co., Ltd.).

The results are shown in Table 1.

Table 1 No. Composition
Uniformity (%) 1 Ink layer composition 1 7
02 Ink layer composition 2 603
Ink layer composition 3 594 Ink layer composition 4
585 (Comparison) Ink layer composition 54 From the results in Table 1, the effects of the present invention are clear.

It was also confirmed that the print clarity, storage stability, abrasion resistance, and transferability were the same or better than conventional products.

Claims (1)

[Claims] (1) A transfer medium for thermal recording having an ink layer on a substrate, wherein the ink layer contains a resin and a pigment having a number average molecular weight of 30,000 or less.