JPH0445993A - Sublimation type thermal transfer sheet - Google Patents

Abstract

PURPOSE:To improve storage stability by preventing fusion at the time of thermal transfer and the transfer of ink to the lubricating heat-resistant layer of a base material sheet by forming an ink layer by providing the lubricating heat-resistant layer to the single surface of the base material sheet and forming an ink layer to the other single surface thereof by applying sublimation transfer type ink containing a specific polyvinyl acetal resin thereto. CONSTITUTION:Sublimation transfer type ink for forming an ink layer is prepared by dissolving a sublimable disperse dye in a solvent along with a binder and applied to the single surface of a base material sheet. The binder is selected from polyvinyl formal wherein the alkyl group R of formula (I) is H, polyvinyl propylal wherein the alkyl group R is C2H5, polyvinyl pental (R=C4H9) wherein the number of carbon atoms in the alkyl group R is 4 or more, polyvinyl hexal (R=C5H11) and polyvinyl heptal (R=C6H13) and, when an isocyanate compound is mixed with this binder, dye holding power increases still more.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sublimation thermal transfer sheet used in thermal transfer recording devices such as thermal printers, thermal typewriters, and lasers.

[Prior Art] This type of thermal transfer sheet is provided with a slippery heat-resistant layer on the back side of a base sheet, and an ink layer is formed on the surface of the layer by coating an ink containing a disperse dye or the like that sublimes when heated. Ru. Thermal transfer according to the image information is performed from the back side of the sheet provided with this slippery heat-resistant layer using a thermal head, laser, etc., and the image is transferred to the object to be thermally transferred.

Traditionally, ink contains a binder in addition to sublimable dye.
In addition to saturated polyester resins, polycarbonate resins, and cellulose resins, examples of this binder include polyvinyl acetoacetal resin (among polyvinyl acecool resins).
JP-A-63151484) and polyvinyl butyral resin (JP-A-6 (I-101087)) are used.

That is, polyvinyl acetoacetal resin has the following formula (T
) The alkyl group R of the polyvinyl acecool resin is CH3, and the alkyl group R of the polyvinyl butyral resin is C3H7.

[Problems to be Solved by the Invention] However, among conventional binders, saturated polyester resins or polycarbonate resins have a relatively large gripping force for disperse dyes, but have a problem in that they tend to fuse to receiving paper during thermal transfer. On the other hand, polyvinyl acetoacetal resin, polyvinyl butyral resin, or cellulose resin is difficult to fuse to receiving paper during thermal transfer, but does not have sufficient gripping power for disperse dyes. Specifically, the above-mentioned conventional binder is contained in each of yellow, magenta, and cyan inks, and each ink (based on yellow, magenta, and cyan) is coated on the surface of three sheets for dye sublimation type thermal transfer. When wrapped around a vinyl chloride tube with a diameter of 1 inch many times and kept continuously in a constant temperature room at 60°C for 96 hours, the dispersion dye 11 that makes up the yellow, magenta, and cyan ink layers becomes a base sheet. There was a problem that caused the dye transfer phenomenon to transfer to the slippery heat-resistant layer on the back side.

The purpose of the present invention is to prevent the ink from fusing to the receiving paper during thermal transfer, and to ensure that the ink does not transfer to the slippery heat-resistant layer on the back surface of the base sheet even if the ink is wrapped many times under conditions higher than room temperature, overlapped, and left for a long time. Another object of the present invention is to provide a j' flower type thermal transfer sheet having good storage stability.

[Means for Solving the Problems] In order to achieve the above-mentioned [I], the sublimation type thermal transfer sheet of the present invention is provided with a slippery heat-resistant layer on one side of the base sheet,
An ink layer is formed by applying a sublimation transferable ink containing polyvinyl acetal resin represented by the following formula (I) consisting of an acetal group, an acetate group, and an alcohol group as a binder and 17 to another side of this base sheet. A sublimation type thermal transfer sheet, wherein the alkyl group R of the polyvinyl acetal resin is )T,
, C2H, or the number of carbon atoms C in this alkyl group R is 4 or more.

The sublimation transfer ink used to form the ink layer of the present invention is prepared by dissolving a sublimable disperse dye in a solvent together with the binder described in 1. The ink is then coated on one side of a base sheet.

The binder is a polyvinyl formal in which the alkyl group R of the above formula (I) is IT, and the alkyl group R is C or H.

polyvinyl butyral, or polyvinylbental (R=C4H,), polyvinyl hexal (R=C5,) in which the number of carbon atoms in the alkyl group R is 4 or more
H, , ), polyvinyl hebutal (RCeH+s), etc. It is preferable to mix an isocyanate compound with this binder because the isocyanate group of the isocyanate compound forms a urethane bond with the alcohol group of the binder, further increasing the dye holding power.

The composition of the ink is that 3 to 15 parts by weight of dye, 1 to 50 parts by weight of binder, 0 to 5 parts by weight of isocyanate compound, and 96 to 50 parts by weight of solvent are present based on 100 parts by weight of the total amount of ink. preferable.

Further, a slippery heat-resistant layer is formed on the surface of the base sheet opposite to the surface on which the ink layer is formed to prevent sticking (fusion). The slippery heat-resistant agent forming the slippery heat-resistant layer is preferably prepared by dissolving the binder described in 1 above in a solvent, and more preferably contains an isocyanate compound together with the binder.

Furthermore, it is preferable to form an anchor coat layer in advance on the ink-coated surface, and this anchor coat 1 agent is preferably prepared by dissolving the above-mentioned binder in a solvent. and even more preferable.

As the solvent used in the ink, lubricating heat resistant agent, or anchor coating agent, known solvents such as toluene and methyl ethyl ketone can be used.

As the base sheet of the present invention, a plastic film of about 2 to 25 μm made of polyester, polyimide, polysulfone, polystyrene, vinyl chloride, polycarbonate, etc. can be used.

[Effects of the Invention] As described above, according to the present invention, a binder and a polyvinyl acecool resin having a higher degree of polymerization, a higher molecular weight, and a higher glass transition point than conventional ones are selected; Because we selected a binder that has a higher glass transition point and is highly capable of holding sublimable dyes, the binder components do not fuse to the receiving paper during thermal transfer, and the thermal transfer sheet of the present invention can be used in large numbers at temperatures higher than room temperature. Even if the sheets are wrapped around each other and left for a long time, the ink will not transfer to the smooth heat-resistant layer on the back of the base sheet.

In particular, when an isocyanate compound is mixed with a binder, the isocyanate group of the incyanate compound forms a one-notane bond with the alcohol group of the binder, further increasing the dye holding power and preventing the dye transfer phenomenon.

[Example] Next, the present invention will be explained in detail. “Department” used below is “
Parts by weight.

<Example 1> An ink having the following composition was coated on one side of a 6 μm thick polyester film using a 200-mesh gravure coater, and then left at 400 C for one week to form a slippery heat-resistant layer with a thickness of 0.4 μm.

・Binder binder Bolivinyl phthalate 6000C (electrochemistry) 10 parts Ten;
1 part Surfactant and lubricant homokenol L-18 (Kao)
Part 05: Phosphate ester metal salt power 7-tsuku RD-720 (Toho Chemical)
05 parts/solvent methyl ethyl ketone 940
Next, as an anchor coat 1 layer of the ink layer, an anchor coat 1 agent having the following composition was coated on the opposite side of the polyester film using the same gravure coater, and dried to a thickness of 0.5 mm.
A 2 μm anchor coat layer was formed.

・Binder binder] Nilbroviral BY-111
(Electrochemistry) 20 parts / Isocyanate compound Takenate 1)-11ON (Take E[l Pharmaceuticals)
Part 05: Phosphate ester metal salt force fuck RD-720 (Toho Chemical)
05 parts/solvent ethyl acetate
After applying 970 parts of the anchor coating agent, it was incubated at room temperature for 3F (3 F), and after sufficient aging, four types of inks prepared according to the following formulations were applied onto the anchor coating layer: yellow, magenta, cyan, 1 of each color in order of black
The entire width of the film was coated in 7.3 cm increments to obtain a heat transfer sheet I.

(a) Yellow ink/dye MS Yellow VP (Mitsui Toatsu Dye) 2
Part 0 fist dye Macrolex Yellow 3G (C
, 1,5olvent Yellow 93) (Ha'inyl) 20 parts/Binder binder Polyethylene chloride 6000C (
Electrochemistry) 10 parts Polyvinylbrobyral BY-111 (same) 30 parts Isocyanate compound bamboo) D-11ON (Bu 11 Yakuhin)
10 parts: Surface improver for coating acceleration = MCF-323 (Inuguchi Hon Ink)
02 parts/solvent chlorohensen
908 parts (b) Magenta ink/dye Re5irene Red TB (C, 1, Di
sparse Red 60) (Ha'inil)
20 parts Dye Macrolex Red V
iolet R (C, 1, Disperse Vio
let 31) (/1' inyl) 10 parts・
Dye MS Magenta VP (Mitsui Toatsu Dye)
20 parts/Binder binder AY-21 (
Electrochemistry)・Isocyanate compound Takenate D-11ON (substitute chemical)・Surface improver for coating promotion Tefenser-MCF-323 (Dai EI main ink)
・Solvent Toluene (c) Cyan ink ・Dye MS Cyan VP (Mitsui Toatsu Dye) ・Dye MS Cyan VPG (Mitsui Toatsu Dye) ・Dye Ce
res Blue GN (C, 1,5olvent Blue 63) (vinyl) dye Foron Brlliant B
lue S-RPIPK (C, 1, Disperse
Blue 354) (Sand)/Binder binder Polyh'nylhexanol AY-22 (electrochemistry)/Isocyanate compound Taken) D-11ON (Take 11 Yakuhin)/Solvent Methyl ethyl ketone/Solvent Toluene 02 parts 923 parts 30 parts 10 parts 20 parts 400 parts 465 parts (d) Black ink/dye Foron Br1lliant Blue S
-RPIPK(C, 1, Disperse Blue
354) (Santo') 5.0 parts Dye Foron Rubine 5E-GFL PIPK
(C, 1, Disperse Recl 73) (
Sand) 2.5 parts Dye Foron
Br1lliant Yellow S-6GL PI
PK (C, 1, Disperse Yellow
231) (Sand) 25 parts/Binder binder Polyvinylph'Tyral 3000K
(Electrochemistry) 20 parts Carbonyl vinylbrobyral BY-111, (1) 20 parts Isocyanate compound Takenate D-1,1ON (Substitute chemical)
lO parts ° solvent 1,2 dichloroethane
850 parts (Example 2) After coating one side of a 6 μm thick polyester film with an ink having the composition below using a 200 mesh gravure coater, it was left at 40°C for one week to form a 04 μm thick slippery heat-resistant layer. Formed.

・Binder binder Borihi'Akebono Schiff'Zral 6000C (electrochemical) 200 parts Silicone oil L-722 (Shin-Etsu Chemical) 005 parts ・Isocyanate compound Takenate D-11ON (substitute chemical)
1.00 parts/Phosphate ester metal salt RD-720 (Takuman≦Chemistry)
100 parts/solvent methyl ethyl ketone
95 and 95 parts Next, on the opposite side of the above polyester film, as an anchor coat layer of the ink layer, an anchor coat agent having the following composition was applied using the same gravure coater, and dried to form an anchor coat 1 layer with a thickness of 02 μm. did.

・Binder binder polymer BY-111
(Electrochemistry) 20 parts/Isocyanate compound/Takenate D-11ON (substitute drug)
05 parts/Phosphate ester metal salt h'fugammafuku RD-720 (Toho Chemical)
05 parts/Solvent methyl ethyl ketone 97.
After applying 0 parts of the anchor coating agent, it was allowed to stand at room temperature for 3 E1, and after sufficient aging, three types of ink (yellow, magenta, and cyan) prepared according to the following formulation were applied to the anchor coating layer. A coating sheet and a thermal transfer sheet were sequentially obtained over the entire width of the film for each color by 32.6 cm.

(a) Yellow ink/dye MS Yellow VP (Mitsui Higashi pressure dyed paddy)
Part 3: Binder binder polyvinylbrobyral BY-111 (
Electrochemistry) 4 parts/Isocyanate compound Takene ID-11ON (substitute drug)
1 part/solvent 1,4 dioxane
92 parts (b) Magenta ink/dye MS Magenta VP (Mitsui Toatsu Dye)
Part 3/Binder binder Ten Livinyl Brochure BY-111
(Electrochemistry) 4 parts: Incyanate compound bamboo 1. D-1,1ON (substitute drug)
1 part/solvent 1,4 dioxane
92 parts (c) Cyan ink/dye MS Cyan VPG (Mitsui Toatsu Dye)
Part 4/Binder + 4 - Binder Borivinylbroviral BYIII (
Electrochemistry) 5 parts / Isocyanate compound Takenate D-1,1ON (substitute drug)
1 part/solvent 1,4 dioxane
90 parts Next, the dye sublimation thermal transfer sheets obtained in Examples 1 and 2 were wrapped around a vinyl chloride tube with a diameter of 1 inch many times and kept in a constant temperature room at 60'C for 96 hours. Storage stability was investigated. As a result, the sublimable dyes constituting each hue of the ink layer did not transfer to the slippery heat-resistant layer on the back side of the sample sheet, and the dye 1 retention property was extremely excellent. Furthermore, the binder component was not fused to the receiving paper during thermal transfer.

Claims (1)

[Scope of Claims] 1) A slippery heat-resistant layer is provided on one side of the base sheet, and a polyvinyl layer composed of an acetal group, an acetate group, and an alcohol group represented by the following formula (I) is provided on the other side of the base sheet. It is a sublimation thermal transfer sheet in which an ink layer is formed by coating a sublimation transferable ink containing acetal resin as a binder, and (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ The alkyl group of the above polyvinyl acetal resin R is H, C
A sublimation thermal transfer sheet characterized in that the number of carbon atoms in _2H_5 or the alkyl group R is 4 or more. 2) A sublimation type thermal transfer sheet containing the polyvinyl acetal resin according to claim 1 in the slippery heat-resistant layer of the base sheet. 3) An anchor coat layer is formed on another side of the base sheet,
A sublimation type thermal transfer sheet having an ink layer according to claim 1 formed on the surface of the anchor coat layer, wherein the anchor coat layer contains the polyvinyl acetal resin according to claim 1. 4) The sublimation thermal transfer sheet according to any one of claims 1 to 3, which contains an isocyanate compound together with a binder.