JPH03292192A - Photosensitive thermal recording material - Google Patents

Abstract

PURPOSE:To enable multicolor recording of images with high quality, by providing on one side of a support a porous microcapsule layer comprising a binder and porous microcapsules dispersed therein, the microcapsules containing a dye precursor, a polymericable monomer and a photopolymerization initiator as main constituents. CONSTITUTION:A photosensitive thermal recording medium comprises a support, e.g. a PET film, and a porous microcapsule layer provided on one side of the support. The microcapsule layer comprises a binder and a mixture of at least two kinds of porous microcapsules dispersed therein, the microcapsules containing a dye precursor, a photo-polymerization initiator and a polymerizable monomer as main constituents encapsulated by using an in situ polymerization method singly or in combination with a coacervation method. A recording material comprises a support, e.g. a paper, and a color developer layer on one side of the support. The color developer layer comprises a binder in which is dispersed a color developer capable of developing the dye precursor by reacting therewith. Multicolor images are recorded on the recording material through thermal transfer from the photosensitive thermal recording material.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a light and heat sensitive recording material that can be used in a printer as an output of a copying machine, a computer, a computer, etc. The present invention relates to a light and heat sensitive recording material capable of continuous tone recording using a porous microcapsule with a bottom.

[Summary of the invention]

In the present invention, porous microcapsules containing a dye precursor, a polymerizable monomer, and a photopolymerization initiator as main components are formed on one surface of a support using an in-5-in-titu polymerization method or an in-situ polymerization method.
Using a combination of 5 itu polymerization method and coacervation method, a porous microcapsule layer dispersed in a base binder is used as a light and heat sensitive recording medium, and a dye is placed on one side of a separate support such as paper. Continuous gradation recording can be performed by thermal transfer from a light- and heat-sensitive recording medium to a recording medium provided with a color developer layer in which a color developer capable of reacting with a precursor to develop color from a dye precursor is dispersed in a binder. This is a light and heat sensitive recording material that is capable of recording high-quality multicolor images.A photopolymerization initiator with a photosensitive wavelength of λ1 and a dye precursor that develops a cyan color are combined and infused together with a polymerizable monomer.
The product is encapsulated in porous microcapsules using a combination of 5 in situ polymerization method or 1 n situ polymerization method and coacervation method, and is further combined with a photopolymerization initiator having a photosensitive wavelength of λ2 and a dye precursor that develops a magenta color.
In addition, a photopolymerization initiator with a photosensitive wavelength of λ3 and a dye precursor that develops a yellow color are combined (λ1, λ2, λ3
(all have different wavelengths and are separated by 5Q nm or more).
At least two types of microcapsules encapsulated in porous microcapsules using a 5-itu polymerization method or a combination of an in-5-itu polymerization method and a coacervation method are dispersed in the porous microcapsule layer, and each photopolymerization The purpose is to create a latent image of an image by irradiating it with light corresponding to the photosensitive wavelength of the initiator, and then developing it by heating with a heat roller or infrared rays to obtain a high-quality multicolor recorded image with continuous gradation. There is.

[Conventional technology]

Conventional heat-sensitive recording materials are generally those in which thermochromic dyes are coated on a support such as paper, and the color is developed by heat from a thermal head or the like for recording. Furthermore, carbonless paper is a typical recording material to which microcapsules are applied, and the resolution depends on the pressurized area of a pressurized object such as a ballpoint pen.

In addition, as a recording material that applies light energy and microcapsules, Japanese Patent Application Laid-Open No. 58-88739 and Japanese Patent Application Laid-Open No. 58-17432 disclose a light- and heat-sensitive recording material recording sheet that uses light to create a latent image of an image. By destroying the microcapsules with pressure, the contents of the microcapsules are released, and the dye reacts with a color developer to develop color and produce an image.

Further, in Japanese Patent Application Laid-open No. 60-214990, after an image is formed by heat, the image is fixed and recorded by curing the photocurable resin inside the uncolored microcapsules using light energy.

[Problem to be solved by the invention]

With conventional heat-sensitive and pressure-sensitive recording sheets, the microcapsules are destroyed by high pressure, which causes image unevenness due to uneven pressure in the pressurized area, increases the size of the device, and prevents high-speed recording. . Further, in the fixing type using light energy, the resolution of the image depends on the heating element that is the thermal energy source, so there is a problem that an image with high resolution cannot be obtained.

(Means for Solving Illi!I) In order to solve the above problems, in the present invention, compounds of the following combinations are incorporated as main components on one side of a support such as a PET film, and in At least two porous microcapsules synthesized using a 5 itU polymerization method or a combination of an in 5 itU polymerization method and a coacelvage method
A porous microcapsule layer is prepared by mixing two or more types of microcapsules and dispersing them in a binder to form a light- and heat-sensitive recording medium, and a dye precursor is reacted with the dye precursor on one side of a separate support such as paper. A light- and heat-sensitive recording material was prepared in which a multicolor image can be recorded by thermal transfer from a light- and heat-sensitive recording medium onto a recording medium provided with a color developer layer in which a color developer capable of developing color is dispersed in a binder.

・Cyan color dye precursor, photopolymerization initiator with photosensitive wavelength at λl, polymerizable monomer ・Magenta color dye precursor, photopolymerization initiator with photosensitive wavelength at A2, polymerizable monomer ・Yellow color dye precursor, A3 The degree of polymerization of the polymerizable monomer in the porous microcapsules is increased by irradiating the photopolymerization initiator and polymerizable monomer with the photosensitive wavelength of the photopolymerization initiator and the polymerizable monomer in accordance with the image to the photosensitive and thermosensitive recording medium. changes, and during thermal transfer, the amount of permeation of the dye precursor released from the porous microcapsules is controlled according to the degree of polymerization, making it possible to express continuous gradations and record multicolor images.

[For production]

Irradiating the light and heat sensitive recording medium of the light and heat sensitive recording materials of the present invention with light corresponding to an image signal from a CRT or the like to form a latent image on the polymerizable monomer in the porous microcapsules in accordance with the image signal, An amount of dye precursor corresponding to the image signal is transmitted through the porous microcapsule by heat from a heat roller, thermal head, or infrared rays, transferred to the recording medium, and reacts with the color developer in the color developer layer. It is possible to record multicolor images with continuous gradation and high image quality.

〔Example〕

This will be explained below based on the drawings. FIG. 1 shows a schematic cross-sectional view of the porous microcapsule of the present invention.

The porous microcapsules 1 are synthesized using an in-5-itu polymerization method or a combination of an in-5-itu polymerization method and a coacervation method, and the porous microcapsule film 2 is a porous film having many pores 3. The contents contained in the microcapsule 1 can be released by thermal stimulation. The porous microcapsule 1
The photopolymerization initiator 5 in the photopolymerization initiator 5 has its absorption wavelength as a photosensitive wavelength, and the photopolymerization initiator species is generated by light at the photosensitive wavelength to polymerize the polymerizable monomer 6, and the polymerizable monomer 6 is cured. Furthermore, since the degree of polymerization can be controlled by the energy of the photosensitive wavelength, the amount of inclusions released from the porous microcapsules 1 can be controlled by heat depending on the degree of polymerization.

FIG. 2 is a schematic cross-sectional view showing a light and heat sensitive recording medium 11 of the light and heat sensitive recording materials of the present invention.

Photopolymerization initiators 5a, 5b, and 5C, each having a different photosensitive wavelength, a polymerizable monomer 6, and dye precursors 4a, 4b, and 4c are encapsulated on a support 9a such as a PET film. 5it
Porous microcapsule a synthesized using a combination of u-polymerization method and coacervation method, 7. The structure includes a porous microcapsule layer 10 in which particles b and 7c are dispersed in a binder 8a.

FIG. 3 is a schematic diagram showing the exposure state of the photosensitive and thermosensitive recording medium of FIG. 2. FIG. λ1, λ depending on the image signal from CRT etc.
2. When the light 12a, 12b, 12c with the wavelength of λ3 is irradiated, the polymerizable monomers 6 in the porous microcapsules 7a, 7b, 7c react according to the energy of the light with the respective wavelength. It can be cured to form a latent image.

FIG. 4 is a schematic diagram showing the thermal transfer state of the light and heat sensitive recording material. As shown in FIG. 3, heat from a heating element 17 such as a thermal head is applied to the porous microcapsule layer 10 of the photosensitive and thermosensitive recording medium 11 on which a latent image has been formed on the support 9a.
By applying light from the side, the dye precursors 4a, 4b, and 4c pass through the porous microcapsule film 2 of the porous microcapsule, which remains uncured even when irradiated with light, and the color developer 13 in the color developer 114 passes through the porous microcapsule film 2 of the porous microcapsule. It is possible to obtain colored parts 16a, 16b, and 16c of each color corresponding to the image signal by reacting with the image signal.
Multicolor images can be recorded.

In the present invention, melamine-
Examples include formalin resin, urea-formalin resin, and the like. In addition, examples of constituent materials of the porous microcapsule film using the coacervation method include styrene-butadiene resin, styrene-maleic anhydride resin, and the like.

Examples of leuco dyes used as pigments for expressing images include crystal violet lactone, rhodium B lactam, malachite green, and 3-dialkylamino-7-
Examples include dialkyl amyl fluorane and benzoyl leucomethylene blue.

Color developers for coloring the leuco dye include aromatic carboxylic acid metal salts such as salicylic acid and its derivatives, clays such as acid clay, activated clay, and bentonite;
Phenol compounds such as α-naphthol, β-naphthol, bisphenol A, etc. can be used.

As the binder, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, styrene-butadiene latex, etc. can be used.

Polymerizable monomers are the main components in porous microcapsules and are also used as solvents to dissolve dye precursors and photopolymerization initiators. It is necessary to have the ability to smoothly release the dye precursor from the porous microcapsules when the dye precursor is applied. Additionally, since the size of porous microcapsules is determined by emulsifying the capsule liquid in water, one important factor is that the polymerizable monomer used as the solvent for the capsule liquid is insoluble in water. It is. If an effective polymerizable monomer is solid at room temperature, it can be used in combination with other polymerizable monomers that are liquid at room temperature. It is also possible to dissolve polymerizable monomers that are solid at room temperature in water-insoluble oils (such as diisopropylnaphthalene), although they do not exhibit polymerizability, but in this case, they do not completely polymerize. However, there is a problem in that the dye precursor oozes out from the porous microcapsules without being completely cured.Effective polymerizable monomers include monomers with two or more ethylenically unsaturated groups and those with ethylenic terminals or side chains. Polymers with unsaturation can be used.These compounds include polyesters with acrylate or methacrylate ends, epoxy resins with acrylate or methacrylate ends, and acrylic esters or methacrylic acid of polyhydric alcohols. These are esters.Specifically, the compounds included in them include diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, and polyethylene glycol diacrylate. Acrylate, polyethylene glycol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate,
In addition to pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, ethylcarpitol acrylate, ethylcarpitol methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, the following acrylates can be mentioned. .

A A B M-NThM-A, AffX-Y")'
TIX-A Here, A: diacrylic acid, M: dihydric alcohol, N: dibasic acid, X: polyhydric alcohol, Y: polybasic acid.

As the photopolymerization initiator, quinone, acyloin, diazoanthrone, diazonium salt, diazophenanthrone, disulfide, aromatic azide, aromatic ketone, aromatic azosulfonate, aromatic carbazide, etc. can be used.

Examples of the present invention are shown below, but the present invention is not limited thereto.

(Example 1: Preparation of prepolymer) 10 parts by weight of melamine was added to 30 parts by weight of a 37% formaldehyde aqueous solution and reacted at 60°C for 15 minutes. Then, 1 part by weight of glycine was added and reacted for 1 minute to form a prepolymer. An aqueous polymer solution was obtained. Even if this prepolymer aqueous solution is left to stand, polymerization may proceed naturally and it may harden, so it is necessary to encapsulate it immediately after preparation.

(Example 2: Synthesis of magenta-colored capsules) 2 parts by weight of a leuco dye that develops a magenta color was added to the polymerizable monomer trimethylolpropane triacrylate) (TMPTA).
) 25 parts by weight, left to stand and cooled to room temperature, and then added safranin and triphenyl as a photopolymerization initiator.
-Butylporon complex compound (sensitivity wavelength: 500 nm)
O.

1 part by weight of N,N-dimethylformamide (DMF) 1
It was mixed with the dissolved part by weight and thoroughly stirred to obtain a capsule encapsulating liquid. This capsule liquid was mixed with 200 parts by weight of water adjusted to pH 4, and mixed with 500 parts by weight using a homogenizer.
Emulsification and dispersion was carried out for about 5 minutes at 0 rpm. This dispersion was stirred with a mechanical stirrer and heated to 60°C in a hot water bath, and the previously prepared melamine-formalin resin prepolymer was added dropwise, and stirring was continued for about 3 hours while maintaining the temperature at 60°C. At this time, if the prepolymer is not dropped immediately after preparation, the prepolymer may become polymerized and encapsulation may not be possible.

From the porous microcapsule dispersion thus obtained,
Porous microcapsules were separated by a centrifugal separator.

(Example 3 Bottom of a rainbow-colored capsule) In Example 1, the same amount of leuco dye that develops a cyan color was used,
Methylene blue and trifel-n are used as photopolymerization initiators.
-Butyl boron complex compound (sensitivity wavelength: 650 nm)
Cyan capsules were synthesized using 0.1 part by weight and in the same manner.

(Example 4: RFC of yellow capsule) Example 1
In the test, 2 parts by weight of a leuco dye that develops a yellow color was used, and a combination of 1.0 parts by weight of hensifhenone and 0.4 parts by weight of Michler's ketone (sensitivity wavelength: 400 nm) was used as a photopolymerization initiator. Yellow capsules were then synthesized using the same method.

(Example 5: Preparation of photosensitive and thermosensitive recording medium) Equal amounts of the porous microcapsules of each color synthesized in this manner were added to an aqueous solution of 5% (W/W) styrene-maleic anhydride copolymer in an amount equal to the total amount of capsules. The dispersed product is used as a capsule dispersion liquid.

Apply this capsule dispersion liquid onto a support such as a PE-T film using a bar coater (Yoshimitsu Seiki: Bar Coater-5lo).
The film was coated using the following method and thoroughly dried at room temperature to obtain a light- and heat-sensitive recording medium.

(Example 6: Preparation of recording medium) 20 parts by weight each of bisphenol A and silica powder as a color developer were added to an aqueous solution of 5% (W/W) polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) using a ball mold. The color developer liquid dispersed in this process was coated onto a support such as paper using a bar coater (Bar Coater #20 manufactured by Yoshimitsu Seiki Co., Ltd.) and sufficiently dried at room temperature to obtain a recording medium.

(Example 7: Evaluation of light and heat sensitive recording materials) A 300W xenon seat arc lamp (manufactured by Ushio Inc.: UYX) was used as a light source for evaluating the characteristics of the light and heat sensitive recording materials produced.
-300), and in order to limit the wavelength of the light, an interference filter (manufactured by MELLES GRI OT) is used to irradiate each photosensitive wavelength of the photopolymerization initiator onto the light and heat sensitive recording paper to connect the latent bodies of the image. A W body obtained by coloring using a thermal head printing device (manufactured by Taishoku Denki: TH-Ml) was used.

As a result, the light and heat sensitive recording paper formed images according to the light irradiation time and was also capable of continuous gradation recording. In addition, selective color development using light was possible, and a multicolor image could be formed.

In areas where coloring is not required, the polymerizable monomer is cured by light irradiation and the dye does not develop color, so it was possible to obtain a good image with no background fading.

〔Effect of the invention〕

As described above, in the present invention, a color developer layer is provided on a support such as paper as a recording medium, and a dye precursor, a polymerizable monomer, etc. are placed on a separate support such as a PET film. Porous microcapsules containing a photopolymerization initiator in 5
By using a combination of in-tu polymerization method or in-5-itu polymerization method and core cell basis method to create a structure with a porous microcapsule layer dispersed in a binder, there is little background fog and the whiteness of the white part is reduced. It is possible to provide a light- and heat-sensitive recording material capable of recording good, continuous gradation, and high-quality multicolor images.

[Brief explanation of the drawing]

FIG. 1 shows a schematic diagram of a porous microcapsule used in the photosensitive and thermosensitive recording material of the present invention, FIG. 2 is a sectional view of the photosensitive and thermosensitive recording medium of the present invention, and FIG. FIG. 3 is a cross-sectional view showing an exposure state. FIG. 4 is a schematic diagram showing the thermal transfer state of the photosensitive and thermosensitive recording medium. 1 ・ ・ 2 ・ ・ 3 ・ ・ 4 ・ ・ 4a ・ 4 b ・ 4 C ・ 5 ・ ・ 5 a ・ 5b ・ 5 C ・ 6 ・ 7 a ・ 7 b ・ 7 C Porous microcapsule Porous micro Capsule membrane Pore Dye precursor Cyan dye precursor Magenta dye precursor Yellow dye precursor Photopolymerization initiator λ1 photopolymerization initiator λ2 photopolymerization initiator λ3 photopolymerization initiator polymerization Porous microcapsules exposed to light with the monomer λ1 Porous microcapsules exposed to light λ2 Porous microcapsules exposed to light λ3 8 a ・ 8 b ・ 9 a ・ 9 b ・ 10 ・ ・ 11 ・ ・ 12 a ・ 12 b ・ 12 C ・ 13 ・・ 14 ・ ・ 15a ・ 15b ・ 15c ・ 16a ・ 16b ・ 16C ・ 17 Porous microcapsules cured with color developer layer λ1 Porous microcapsules cured with λ2 Porous microcapsules cured with λ3 Cyan coloring area Magenta coloring area Yellow coloring area Heating element Above

Claims (9)

[Claims] (1) On one side of the support, a dye precursor, a polymerizable monomer, and a photopolymerization initiator capable of initiating polymerization of the polymerizable monomer by irradiating the polymerizable monomer with light at a sensitive wavelength are included as main components. porous microcapsules in
A porous microcapsule layer synthesized using an in-situ polymerization method or a combination of an in-situ polymerization method and a coacervation method and dispersed in a binder is provided as a light- and heat-sensitive recording medium, and it can be colored by reacting with the dye precursor. 1. A light and heat sensitive recording material which is capable of recording a multicolor image by heat transfer from a light and heat sensitive recording medium onto a recording medium provided with a color developer layer on a support, in which a color developer is dispersed in a binder. . (2) The capsule membrane that forms the outer shape of porous microcapsules is a porous membrane with many pores, and when heat is applied from the outside, the pores of the porous membrane of the porous microcapsules can be 2. The light and heat sensitive recording material according to claim 1, having a function of allowing the inclusions to pass through the porous microcapsules and be released to the outside of the porous microcapsules. (3) The light and heat sensitive recording material according to claim 1, wherein the capsule membrane material of the porous microcapsules in the in situ polymerization method is selected from among the combinations of compounds shown below. [1] Melamine-formalin [2] Urea-formalin (4) The light and heat sensitive recording material according to claim 1, wherein the porous microcapsule membrane material in the coacervation method is selected from the following compounds. [1] Styrene-butadiene copolymer [2] Styrene-maleic anhydride copolymer [3] Gelatin [4] Gelatin-gum arabic system (5) The photopolymerization initiator itself is a compound that undergoes a chemical change in response to light energy and generates a polymerization initiation species, or a sensitizer that undergoes a chemical change in response to light energy, and the sensitizer that has undergone a chemical change. 2. The light and heat sensitive recording material according to claim 1, further comprising a polymerization initiating species generator which reacts with a polymerization initiating species to generate a polymerization initiating species. (6) The porous microcapsule layer has different photosensitive wavelengths (at least each photopolymerization initiator has a photosensitive wavelength of 50 nm).
2. The photosensitive and thermosensitive recording material according to claim 1, comprising at least two different types of porous microcapsules each separately containing photopolymerization initiators separated by m or more. (7) The light and heat sensitive recording material according to claim 1, wherein the dye precursor is a leuco dye. (8) The light and heat sensitive recording material according to claim 1, wherein the polymerizable monomer is a compound that is crosslinked and cured by light energy. (9) The binder has the function of fixing the porous microcapsules in the porous microcapsule layer and preventing them from separating from the developer layer or support, and when heat is applied, 2. The light and heat sensitive recording material according to claim 1, wherein the viscosity is reduced so that the inclusions released from the porous microcapsules can be transferred to the color developer layer.