JPH09104177A - Coloring matter donor element for thermosensitive coloring matter transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a sensitometry change at a time of preservation and to keep coloring matter efficiency at a time of printing. SOLUTION: In a coloring matter donating element for thermal coloring matter transfer formed by forming a coloring matter layer wherein image coloring matter is contained in a polymeric binder on the surface of a support, the coloring matter layer further contains a stabilizer containing polycarbonate polyol of an origomer with a mol.wt. of 1000-10000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates to the use of certain polycarbonate polyol-based stabilizers in dye-donor elements for thermal dye transfer devices.

[0002]

2. Description of the Related Art Recently, a thermal transfer apparatus for obtaining a print from an image generated electronically from a color video camera has been developed. According to one method of obtaining such prints, an electronic image is first subjected to color separation by a color filter. Next, each color separation image is converted into an electric signal. Then manipulate these signals to get cyan,
It generates magenta and yellow electrical signals and transmits these signals to a thermal printer. To obtain a print, a cyan, magenta or yellow dye-donor element is placed face-to-face with a dye-receiving element. The two elements are then inserted between the thermal print head and the platen roller. Heat is applied from the back side of the dye-donor sheet using a line-type thermal printhead. The thermal printhead has a number of heating elements and is heated up sequentially in response to cyan, magenta and yellow signals. Thereafter, this process is repeated for the other two colors. Thus,
A color hard copy corresponding to the original image viewed on the screen is obtained. Details of this method and the apparatus for performing it are described in U.S. Pat. No. 4,621,271.

An important requirement for any thermal dye-donor element is to maintain performance for its useful life without degrading image quality. The dye layer of the dye-donor element for thermal dye transfer of resistive heads generally comprises a polymeric binder and a diffusible dye. The percentage of dye contained in this layer is very high and is typically in the range of 20-80%. Usually the dye is either dissolved in the binder or phase separated to form small domains. During storage of the donor element, the temperature and humidity can be high, and when the donor element is wound into a spool, a dye layer is applied to the slip layer coated on the back side of the donor element. Will come into contact. The slip layer may contain a migratory lubricating oil or substance that can act as a plasticizer or solvent for the dye layer.
For this reason, the dye becomes migrating, and there is a possibility that the dye layer changes, such as further phase separation, migration of the dye to the surface, and in some cases, crystallization of the dye. It is also possible that the dye is transferred to the slip layer. Such changes generally result in sensitometric variations, uneven printing due to light or dark spots, and migration of dye from high to low density areas of the print.

US Pat. No. 5,288,691 describes a monomer containing a phenylindane moiety as a stabilizer for a dye-donor element to minimize sensitometric changes on storage of the donor element. It is described to use a mixture of oligomeric glass substances or compounds. However, there is no mention of using the compounds according to the invention for such purposes. US Pat. No. 5,266,551 describes the use of polycarbonate polyols capable of reacting with multifunctional isocyanates to form crosslinked polymer networks in dye-receiver elements for thermal dye transfer printing. ing. However, there is no mention in this U.S. patent of the utility of such materials as stabilizers in dye-donor elements.

[0005]

Prior art dye-donor elements suffer from a change in their sensitometry upon storage. It is an object of the present invention to provide a stabilizer for a dye-donor element that has minimal sensitometric changes during storage and storage and that maintains dye efficiency during printing.

[0006]

These and other objects include a dye-donor element for thermal dye transfer comprising a support having on its surface a dye layer containing an image dye in a polymeric binder, The dye layer has a molecular weight of 1000 to 10
000, preferably 1000 to 5000, is achieved according to the invention for a dye-donor element for thermal dye transfer, which further comprises a stabilizer comprising an oligomeric polycarbonate polyol.

In a preferred embodiment of the invention, the stabilizer comprises an oligomeric polycarbonate polyol containing a mixture of aromatic and / or aliphatic diols linked by carbonate groups and having two terminal hydroxy groups. included. In another preferred embodiment of the invention, the stabilizer can be represented by the formula:

[0008]

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In the above formula, R and R'each independently represent a divalent aliphatic group having about 2 to about 16 carbon atoms or an aromatic group having about 6 to about 30 carbon atoms, And n is 2-10. The polycarbonate polyol used in the present invention can be obtained by reacting bis (chloroformate) with a diol. If one of the monomers is used in excess, it becomes the end group. Alternatively, bis (chloroformate) may be used in excess to obtain a chloroformate-terminated oligomer, which may then be hydrolyzed to form hydroxyl groups. The polyol can be synthesized from these monomers as an excess of either R or R'according to the following chemical reaction formula.

[0010]

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Examples of bis (chloroformate) that can be used in the above reaction include the following compounds.

[0012]

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M1: bisphenol A bis (chloroformate)

[0014]

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M2: diethylene glycol bis (chloroformate) or

[0016]

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M3: butanediol bis (chloroformate) Examples of diols that can be used in addition to diethylene glycol, butanediol, pentanediol and nonanediol include the following compounds.

[0018]

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M4: Bisphenol A

[0020]

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M5: 2,2 ', 6,6'-tetrachlorobisphenol A

[0022]

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M6: 4,4 '-(octahydro-4,7
-Methano-5H-indene-5-ylidene) bisphenol

[0024]

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M7: 4,4'-bicyclo [2.2.2]
Hept-2-ylidenebisphenol The above monomers and other aliphatic and aromatic diols can be combined to obtain various compositions and compounds with various chain lengths and end groups. The polyol can have an aliphatic hydroxyl end group (eg, diethylene glycol end group) or a phenolic end group (eg, bisphenol A end group) at the end. In addition, phenolic or aliphatic polyfunctionality (>
The alcoholic group (eg, glycerol) of 2) may be added in an appropriate amount to form a branched oligomeric polyol. Examples of stabilizers that can be used in the present invention are given below.

[0026]

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* Represents the aliphatic / aromatic monomer ratio and produces aromatic end groups. ** Represents polystyrene equivalent molecular weight.

[0028]

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* Represents the aliphatic / aromatic monomer ratio and produces aliphatic end groups. ** Represents polystyrene equivalent molecular weight.

In a preferred embodiment of the invention, the stabilizer is present in a concentration of about 5 to about 25% by weight of the dye layer. As the dye donor used in the present invention, any dye may be used as long as it can be transferred to the dye receiving layer by the action of heat. Particularly good results are obtained with sublimable dyes. As an example of a sublimable dye, the following structural formula:

[0031]

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[0032]

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[0033]

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The dyes represented by: and US Pat. No. 4,54
No. 1,830, No. 4,698,651, No. 4,6
Nos. 95,287, 4,701,439 and 4,
Examples include any of the dyes described in Nos. 757,046, 4,743,582, 4,769,360 and 4,753,922. The above dyes may be used alone or in combination.
These dyes can be used at a coverage of from about 0.05 to about 1 g / m ² and are preferably hydrophobic. The use of dye barrier layers in the dye-donor elements of the invention can improve the density of the transferred dye. Such dye barrier layer materials include hydrophilic materials such as those described and claimed in US Pat. No. 4,716,144.

The dye layer of the dye-donor element of the invention can be coated on the support or printed on the support by printing techniques such as gravure. Any material can be used as the support for the dye-donor element of the invention provided it is dimensionally stable and can withstand the heat of the thermal printheads. Such materials include polyesters such as poly (ethylene terephthalate), polyamides, polycarbonates, cellulose esters, fluoropolymers, polyethers, polyacetals, polyolefins and polyimides. The thickness of the support is generally from about 5 to about 200 μm. If desired, U.S. Patents 4,695,288 and 4,
A subbing layer, such as the materials described in 737,486, may be applied to the support.

The dye contained in the dye-donor element of the invention may be a polymeric binder such as a cellulose derivative (eg, cellulose hydrogen phthalate acetate, cellulose acetate,
Cellulose acetate propionate, cellulose acetate butyrate, cellulose triacetate and materials described in US Pat. No. 4,700,207), polycarbonate, polyvinyl acetate, poly (styrene-co-acrylonitrile),
Dispersed in poly (sulfone) or poly (phenylene oxide). Binder is about 0.1 to about 5g
/ M ² .

The opposite side of the dye-donor element of the invention can be coated with a slip layer to prevent the printhead from sticking to the dye-donor element. Such slip layers include solid or liquid lubricants or mixtures thereof, with or without polymeric binders or surfactants. Preferred lubricants are oils or 100
Semi-crystalline organic solids that melt below ℃, for example, poly (vinyl stearate), beeswax, perfluorinated alkyl ester polyether, poly (caprolactone), silicone oil, poly (tetrafluoroethylene), carbowax, poly ( Ethylene glycol) or US Pat. No. 4,7
No. 17,711, No. 4,717,712, No. 4,
The substances described in the specifications of 737,485 and 4,738,950 are mentioned. Suitable polymer binders for the slip layer include poly (vinyl alcohol-co-butyral), poly (vinyl alcohol-co-acetal), polystyrene, poly (vinyl acetate), cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate. Alternatively, ethyl cellulose is included.

The amount of lubricant used in the slip layer varies greatly depending on the type of lubricant, but is generally about 0.00
It is in the range of 1 to about 2 g / m ² . When a polymer binder is used, the lubricant is 0.05 to 50% by weight, preferably 0.5 to 40% by weight of the polymer binder used.
Exists in the range.

The dye-receiving element that is used with the dye-donor element of the invention usually comprises a support having thereon a dye image-receiving layer. The support is poly (ether sulfone), polyimide, cellulose ester such as cellulose acetate, poly (vinyl alcohol-co-acetal).
Alternatively, it can be a transparent film such as poly (ethylene terephthalate). The support for the dye-receiving element may also be a baryter-coated paper, polyethylene-coated paper, ivory paper, condenser paper or synthetic paper [eg DuPont.
It may be reflective as in Tyvek (trademark). Also, a colored support such as white polyester (a transparent polyester in which a white pigment is incorporated) may be used. The dye image-receiving layer is, for example, polycarbonate, polyurethane, polyester, poly (vinyl chloride), poly (styrene-co-acrylonitrile), polycaprolactone, poly (vinyl acetal), for example poly (vinyl alcohol-co-butyral). , Poly (vinyl alcohol-co-benzal), poly (vinyl alcohol-co-acetal), or mixtures thereof. The dye image-receiving layer can be present in any amount that is effective for the intended purpose. In general, good results have been obtained at a concentration of about 1 to about 5 g / m ² .

As noted above, dye-donor elements of the invention are used to form a dye transfer image. This process includes the step of imagewise heating the dye-donor element described above and the step of transferring the dye image to the dye-receiving element to form a dye transfer image. The dye-donor element of the invention may be used in sheet form or as a continuous roll or ribbon. When used in a continuous roll or ribbon, sublimable cyan and / or magenta and / or yellow and / or
Alternatively, it may have alternating regions with more than one dye, such as black or other dyes. Thus, the scope of the present invention includes one-, two-, three- or four-color (and in some cases five or more) elements.

In a preferred embodiment of the invention, the dye-donor element comprises a poly (ethylene terephthalate) -based support in which the cyan, yellow, and magenta regions are coated in a repetitive and sequential manner, and the process described above is repeated for each color. Sequentially carried out to obtain a three-color dye transfer image. Of course, when the above process is performed for only one color, a monochrome dye transfer image is obtained.

The thermal dye transfer assembly of this invention comprises (a) a dye-donor element as described above, and (b) a dye-receiving element as described above, which dye-receiving element comprises a dye image-receiving layer and Overlaid with the dye-donor element so that the dye layer of the dye-donor element is in contact. If a monochrome image is to be obtained, the above assembly containing these two elements can be preassembled as an integral unit. This assembly can be done by temporarily adhering the two elements together at their edges. After transfer, the dye-receiving element is peeled away to reveal the dye transfer image.

When a three color image is obtained, the above assemblage is formed three times using separate dye-donor elements. The element is peeled off after the first dye is transferred. The second dye-donor element (or another area of the donor element with a different dye area) is then brought in register with the dye-receiving element and the process repeated. Similarly, a third color is obtained.

[0044]

The present invention will be further described with reference to the following examples. Example 1 Synthesis of Polycarbonate Polyol from Excess Diethylene Glycol Bis (chloroformate) and Bisphenol A / Aliphatic Hydroxyl End Group (G-
4) In a 1 liter three neck round bottom flask equipped with an argon inlet, mechanical stirrer and addition funnel, diethylene glycol bis (chloroformate) (55.4 g,
0.24 mol) and bisphenol A (45.7 g,
0.2 mol) and ethyl acetate (325 mL) were charged, and the mixture was cooled to 5 to 10 ° C with an ice bath. A solution of triethylamine (40.48 g, 0.4 mol) in ethyl acetate (75 mL) was added slowly over 45 minutes with stirring under a stream of argon. The mixture was filtered from the white precipitate, rinsed with ethyl acetate and the combined ethyl acetate solution was treated with 20 mL of water and 50 mL of acetone and then with 12 g of pyridine to give chloroformate end groups. Was hydrolyzed. The solution was washed with 600 mL water containing 6 mL concentrated hydrochloric acid, three times with 600 mL sodium chloride solution and dried over anhydrous potassium carbonate. The solution was filtered, concentrated on a rotary evaporator to 50-60% solids and precipitated into 3 liters of a 50/50 methanol / ice water mixture. The soft precipitate was triturated with water in a blender to a solidified solid, filtered and air dried.

EXAMPLE 2 Poly (ethylene terephthalate) support having a thickness of 6 μm was coated on both sides with a solvent mixture of propyl acetate / butanol and titanium tetrabutoxide [Tyzor manufactured by DuPont].
A control cyan dye-donor 1 was prepared by coating 0.12 g / m ^{2 of} TBT ™]. On one side of the support, 0.48 g / m ² of poly (vinyl acetal) (Sekisui Chemical) binder and 0.007 g / m ²
Of BYKS732 ™ copolymer of polypropylene oxide and polymethyloctyl siloxane, 98%
Stoddard solvent (BYK Chemie), 0.0
10 g / m ² of PS513 ™ aminopropyl terminated polydimethylsiloxane (Huels), 0.0
A slip layer containing 003 g / m ² of p-toluenesulfonic acid was coated from a diethyl ketone / methanol-based solvent mixture.

On the opposite side of the support, the cyan dye C
-1 (0.37 g / m ² ) and the above cyan dye C-2
(0.11 g / m ² ), cellulose acetate propionate (CAP) binder (acetyl 2.5%, propionyl 45%) (0.35 g / m ² ) and polyethylene particles, polypropylene particles and polyethylene oxide particles Finely ground compound S363NI ™ (Shamrock
(Technologies) (0.02 g / m ² )
And Fluorad ™ FC430 surfactant (3
Co., Ltd. (0.002 g / m ² ) dissolved in a toluene / methanol / cyclopentanone mixture was coated.

Comparative Dye Donor 2 was made in the same manner as Control Dye Donor 1, except that the dye layer contained 0.1
1 g / m ² of comparative stabilizer (below) was added and the CAP binder was adjusted to 0.24 g / m ² to obtain an equivalent sensitometric response. The dye-donor according to the invention was prepared in the same manner as Comparative Dye Donor 2, except that the stabilizers listed in Table 1 were included instead of the comparative stabilizers.

[0048]

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Comparative stabilizer: 2,4,6-trimethylaniline substituted phenylindane

US Pat. No. 5,244,861
38 μm thick microvoided as described
Composite film (OPPalyte ™ 350TW,
Extrusion lamination of Mobil Chemical Co., Ltd. on paper core material
To produce a dye-receiver element. Then get
The following layers were applied to the composite film side of the laminated body in the order listed.
Suffered. (1) Dow Z-6020 coated from ethanol
(Trademark) (Aminoalkyle from Dow Corning)
(Aminotrimethoxysilane) undercoat layer (2) Makrolon coated from dichloromethane
(Trademark) KL3-1013 bisphenol A polycarbonate
Nates (Myles Laboratories)
(1.776 g / m^Two), Lexan ™ 141-
112 Polycarbonate (General Elect
ric) (1.453 g / m^Two), Dibutylphthale
To (0.323 g / m^Two), Diphenyl phthalate
(0.323 g / m ^Two) And FC431 (trademark) Fluo
B Surfactant (3M Company) (0.011 g / m ^Two)
(3) Bisphenol A coated with dichloromethane
(50 mol%), diethylene glycol (49 mol%)
And MW 2,500 polydimethylsiloxane block
Unit (1 mol%) linear condensed copolycarbonate (11
g / m^Two), Fluorad FC431 ™
(0.02 g / m^Two) And Dow-Corning5
10 Silicone fluid (0.01g / m^Two) Consisting of
Bar coat layer

The accelerated storage test was carried out by manually winding a donor sample onto a plastic core under constant tension against the poly (vinyl acetal) slip layer described above, which was (40% RH in a foil lined bag). Enclose with) 60 ℃
It was carried out by placing it in an accelerated storage oven of / 70% RH for 3 days. The results are shown in Table 1.

Eleven-step sensitometric images were printed with the donor samples after incubation and after storage at room temperature. The dye side of the dye-donor element in the form of a strip having an area of about 10 × 13 cm was placed in contact with the dye-receiving element of the same area. The assembly is 60 mm in diameter
Fastened to the step motor that drives the rubber roller of
Then, a thermal head (L-231) manufactured by TDK (temperature control at 30 ° C.) was applied to the dye-donor element side of the assembly at 24.4 N.
It was pressed with a force of (2.5 kg) and then pressed against a rubber roller. 10. Activate the imaging electronics and place the donor / receiver assembly between the printhead and roller.
It was pulled out at a speed of 1 mm / sec. At the same time, the resistive elements in the thermal printhead were pulsed at 64 μsec / pulse at 129 μsec intervals during the 16.9 μsec / dot printing time. An image with graded density was generated by increasing the number of pulses / dot from 0 to 127. The supply voltage to the printhead was 14.5 Volts, with an instantaneous peak power of 0.429 Watts / dot and a maximum total energy of 3.49 millijoules / dot. The value of D _max (step 11) and O.D. D. The changes in the Status A red concentration at = 0.50 due to incubation are shown in Table 1 below.

[0053]

[Table 1]

The above data show that the stabilizer of the invention (G-1
~ G-4) show that the sensitometric change of the dye-donor after incubation was reduced compared to the control sample without stabilizer. In addition, the stabilizer G-1
~ G-3 shows that the sensitometric change after incubation was reduced compared to the comparative stabilizer. In addition, the use of stabilizers G-3 and G-4 resulted in more D than that of the control sample without stabilizer or the comparative stabilizer.
_max increased by 7-9%. Example 3 Example 2 was repeated, except that the materials listed in Table 2 below were used.

[0055]

[Table 2]

The above data show that the stabilizers (G-5 to G-
All of 7) show that the sensitometric change of the dye donor after incubation was reduced compared to the control sample without stabilizer. This result demonstrates that the reduction in sensitometric change achievable with the stabilizers of the present invention is independent of the molecular weight of the stabilizer used.

[0057]

By using the stabilizers of this invention, sensitometric changes during storage of the dye-donor element can be minimized. The stabilizers used in the present invention also exhibit improved dissolution properties in suitable coating solvents.

Claims (1)

[Claims] 1. A dye-donor element for thermal dye transfer comprising a support having on its surface a dye layer containing an image dye in a polymeric binder, said dye layer having a molecular weight of 100.
A dye-donor element for thermal dye transfer further comprising a stabilizer comprising an oligomeric polycarbonate polyol exhibiting 0 to 10000.