JPH041206A - Photopolymerizable resin composition and transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain a photopolymerizable resin composition which can give a transfer recording medium excellent in long-term storage stability by mixing an ethylenically unsaturated compound with a specified photopolymerization initiator. CONSTITUTION:A photopolymerizable composition essentially consisting of an ethylenically unsaturated compound and a photopolymerization initiator, wherein the photopolymerization initiator comprises a polymeric compound having a group able to initiate photopolymerization as a side chain (e.g. a polymeric compound having an aromatic ketone structure of formula I or II or a diketone structure of formula III or the like as a side chain and having a main chain comprising PE, PS or the like). This composition has excellent storage stability, and a recording medium prepared from this composition is an excellent one that scarcely degrades in performance even after long storage.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a photopolymerizable composition suitable for UV inks, UV adhesives, photosensitive planographic printing plates, etc. that utilize photopolymerization reactions, and also relates to photopolymerizable compositions that utilize photopolymerization reactions. The present invention relates to a transfer recording medium used in recording devices such as copying machines and facsimile machines.

[Prior Art 1] The present applicant has previously used a recording medium in which a reaction rapidly progresses when thermal energy and light energy are applied, and the transfer characteristics irreversibly change, and the applicant has developed a recording medium in which the transfer characteristics change irreversibly when thermal energy and light energy are applied thereto. JP-A-62-174195 proposed an image forming method in which an image is formed on a recording medium and this image is transferred to a recording medium. According to this method, a multicolor, high-quality image can be obtained without making complicated movements of the recording medium.

[Problem to be Solved by the Invention 1] An object of the present invention is to provide a recording medium with excellent long-term storage stability for use in the above recording method, and to provide a photopolymerizable composition for constituting the same. It is in.

[Means for Solving the Problems] The above object is to provide a photopolymerizable composition containing a compound having an ethylenically unsaturated double bond and a photopolymerization initiator as essential components, in which the photopolymerization initiator is attached to its side chain. A photopolymerizable composition characterized by being a polymeric compound having a group having a photopolymerization initiating effect, and a photopolymerizable composition that is solid at room temperature and whose transfer characteristics change by applying light energy and thermal energy. This is achieved by a transfer recording medium having a distributed layer of an image forming element on a binder stone formed on a base material.

The photopolymerizable composition of the present invention contains at least a polymer photoinitiator having a group having a photopolymerization initiating function in its side chain, a compound having an ethylenically unsaturated double bond, and a colorant, and as necessary. Depending on the situation, additives such as a binder, a thermal polymerization inhibitor, a plasticizer, and a surface smoothing agent may be included.

Although the reason why the photopolymerizable composition used in the recording medium of the present invention has excellent storage stability is not clear, it is presumed as follows.

When the photopolymerization initiator is a low-molecular-weight one, during long-term storage (especially when stored at high temperatures), the photopolymerization initiator may separate from other components, or the photopolymerization initiator may crystallize, resulting in decreased sensitivity. It is expected that this will decrease. On the other hand, we believe that by using a polymer as a photoinitiator, the compatibility with compounds having ethylenically unsaturated double bonds and binders will be improved, separation will be suppressed, and the decrease in sensitivity will be reduced. It will be done.

Examples of the polymer photopolymerization initiator having a group having a photopolymerization initiating function in the side chain used in the present invention include those containing the structures illustrated below in the side chain.

Aromatic ketone structure diketone structure Examples include.

As the main chain of the polymeric photopolymerization initiator, polyethylene, polypropylene, polystyrene, polyether, polyester, polyurethane, etc. are used.

Furthermore, the compound having an ethylenically unsaturated double bond, which is an essential component of the present invention, refers to a compound having at least one ethylenically unsaturated double bond in its chemical structure, such as chemical compounds such as polymers, oligomers, polymers, etc. It is something that has a form.

Examples include monomers such as methyl acrylate, methyl methacrylate, acrylonitrile, and acrylamide; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid; and ethylene glycol and triethylene glycol. , esters with aliphatic polyol compounds such as tetraethylene glycol, trimethylolpropane, 1,3-butanediol, pentaerythritol, dipentaerythritol, and polyisocyanates (reacted with polyols as necessary). urethane acrylates, urethane methacrylates, and epoxy resins synthesized by the polyaddition reaction of alcohols and amines containing unsaturated double bonds, and urethane acrylates and urethane methacrylates, which are synthesized by the addition reaction of epoxy resins and acrylic acid or methacrylic acid. Examples include epoxy acrylates, polyester acrylates, spin acrylates, polyether acrylates, etc., but the present invention is not limited thereto.

In addition, as a polymer, the main chain has a skeleton of polyalkyl, polyether, polyester, polyurethane, etc.
Examples include those in which a polymerizable reactive group such as an acrylic group, a methacrylic group, a cinnamoyl group, a cinnamylidene acetyl group, and a furyl acryloyl group are introduced into the side chain, but the present invention is not limited thereto. .

Further, as the binder, any organic polymer may be used.

Examples of such organic polymers include polyacrylic acid alkyl esters such as polymethyl acrylate and polyethyl acrylate, polymethacrylic acid alkyl esters such as polymethyl methacrylate and polyethyl methacrylate, methacrylic acid copolymers, and acrylic. Acid copolymers, maleic acid copolymers, chlorinated polyolefins such as chlorinated polyethylene and chlorinated polypropylene, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, or copolymers thereof, as well as polyvinyl alkyl ether, polyethylene, and polypropylene. , polystyrene polyamide, polyurethane, chlorinated rubber, cellulose derivatives, polyvinyl alcohol, polyvinylpyrrolidone, etc., but the present invention is not limited thereto.

These polymers may be used singly or in combination of two or more in an appropriate ratio. Also compatible as a binder,
Waxes are not limited to incompatible waxes and may be used. Any amount of these polymers can be mixed into the total composition.

The colorant is a component contained in order to form an optically recognizable image, and various pigments and dyes are used as appropriate. Examples of such pigments and dyes include inorganic pigments such as carbon black, yellow lead, molybdenum red, and red iron.
Banza Yellow, Benzidine Yellow, Brilliant Carmine 6B.

Examples include organic pigments such as Lake Red C1 Permanent Red F5R and Phthalocyanine Blue, leuco dyes, phthalocyanine dyes, and colorants such as Victoria Blue Lake and Fast Sky Blue.

The amount of the colorant is preferably 0.1 to 30 parts by weight based on the total amount of the binder, photopolymerization initiator, compound having an ethylenically unsaturated double bond, and the like.

Further, in order to prevent a decrease in sensitivity and further improve image resolution, the image forming element may be microencapsulated. In this case, the above-mentioned material is contained in the core portion.

Materials used for the wall materials of microcapsules include gelatin, gum arabic, celluloses such as ethyl cellulose and nitrocellulose, urea-formalin, nylon, tetron, polyurethane, polycarbonate, maleic anhydride copolymers, vinylidene chloride, and polychloride. Examples include polymer systems such as vinyl, polyethylene, polystyrene, and polyethylene terephthalate (PET).

In the transfer recording medium of the present invention, the transfer recording layer changes the physical properties that govern its transfer characteristics by simultaneously applying light energy and thermal energy, at least one of which corresponds to image recording information. A recording medium having on a support, the transfer recording layer comprising at least a colorant and a sensitive component that is sensitive to light energy and the application of heat or heat-converting energy, which is a solid image at room temperature. It is formed from formation elements,
The recording medium is characterized in that it contains at least the photopolymerizable composition of the present invention as the sensitive component.

The transfer recording medium of the present invention has a distribution layer of an image forming element, which is solid at room temperature and whose transfer characteristics change by applying light and thermal energy, as described above, on a binder layer formed on a base material. It can be obtained by forming

Here, microcapsules are generally used as image forming elements.

As the microencapsulation method, any conventionally known method can be applied, such as simple coacervation method, compression method, complex coacervation method, interfacial polymerization method, 1n-situ polymerization method, interfacial precipitation method, and phase separation method. method, spray drying method, air suspension coating method,
Mechanochemical methods are used.

The particle size of the image forming element constituting the recording medium of the present invention is 1
~20μs is preferred, and 3~15u is preferred. In addition, when the image forming element is composed of microcapsules, the average particle size of the microcapsules is 1 to 20 JL11.
is preferable, and particularly preferably 3 to 15 μs. The particle size distribution of the microcapsules is preferably ±50% or less, particularly preferably ±20% or less with respect to the number average diameter. The thickness of the wall material of the microcapsule is preferably 0.1 to 2.0 JJJfi, particularly preferably 0.1 to 0.5.

As the binder, a thermoplastic material may be selected as appropriate, such as ethylene-vinyl acetate copolymer, polyamide, polyester, polyolefin, polyurethane, polychloroprene, nitrile rubber, styrene, etc.
Selected from butadiene rubber, etc. In addition, to improve the heat resistance and solvent resistance of thermoplastic binders,
Other methods include blending with a thermosetting resin or copolymerizing reactive monomers and crosslinking after adhesion.

As the base material, films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetylcellulose, nylon, and polyimide, papers such as condenser paper and glassine paper, and metals such as aluminum are used. The above-mentioned binder can be dissolved in a solvent or made into an emulsion and applied onto these base materials with an applicator, and then the solvent and water can be volatilized, or the material can be melted by heat on a hot plate and then applied with a wire bar. It is formed by coating and cooling to room temperature, or by using a method such as spraying or gravure printing. Then, when bonding the image forming element, adhesiveness may be generated by heating again.

Methods for adhering the image forming element in a single layer on the binder include not only the simple sprinkling method, but also the method of overlaying the image forming element on a separately prepared support.
A method may also be used in which a base material coated with a binder is conveyed in contact with a container containing an image forming element in advance. This can be done by taking measures to remove the excess amount, if necessary.

The transfer recording medium of the present invention can be suitably used in the method disclosed in JP-A-62-174195 and the like. This method involves applying at least one type of energy among the plurality of types of energy to a transfer recording medium having a transfer recording layer in which physical properties governing transfer characteristics change by applying a plurality of types of energy to correspond to recorded information. This is an image forming method in which a transferred image is formed by applying the plurality of types of energy under application conditions, and then transferred onto a recording medium.

In the image forming method, a method of forming a transferred image on the transfer recording medium of the present invention using light energy and thermal energy and making the thermal energy correspond to recorded information will be described.

The transfer recording layer of the transfer recording medium has a softening temperature Ts, and T
At temperatures higher than s, its viscosity decreases rapidly. Here, the transfer recording layer is uniformly irradiated with light corresponding to the absorption wavelength of the photopolymerization initiator contained in the transfer recording layer, and at the same time, a heating means such as a thermal head is used to raise the transfer recording layer to a temperature of Ts or higher according to the recorded information. When partially heated, the viscosity of the portion heated above Ts rapidly decreases, the diffusion rate of the photopolymerization initiator and polymerizable monomer in the transfer recording layer increases, and the polymerization reaction rapidly proceeds. On the other hand, in the non-heated area, the viscosity of the transfer recording layer does not decrease, so the photopolymerization initiator and polymerizable monomer do not diffuse sufficiently and the polymerization reaction occurs only partially.

If the transfer recording medium on which the transferred image has been formed is brought into pressure contact with the transfer target and heated to a predetermined temperature necessary for transfer, for example, a temperature higher than Ts, the polymerization reaction will partially occur in the non-heated part of the thermal head. The portion where only a portion of the image is generated is transferred to the transfer recording medium, and the heated portion of the thermal head has sufficient polymerization, so the adhesiveness with the transfer target recording medium is low, and the transfer is not performed. In this way, an image is formed using light energy and thermal energy.

In addition, in the above example, the softening temperature T of the transfer recording layer is used as the physical property value governing the transfer characteristics and polymerization reaction amount of the transfer recording layer.
Although explained in section s, in addition to this, the glass transition point, melting temperature, etc. of the transfer recording layer may be used.

Further, the transfer recording layer is composed of several types of particulate bodies or microcapsules containing colorants exhibiting several different color tones coated on a support, and the photopolymerization initiator contained therein is By changing the sensitive wavelength range, it is possible to form multicolor images.

[Example] The present invention will be specifically explained below using Examples.

(Preparation of recording medium) Mix 100 g of water and 26 g of isobutylene-maleic anhydride copolymer (20.6%, manufactured by Kureha Chemical Co., Ltd.) of microcapsules,
3.1g of pectin was added to this and stirred for 20 minutes.
The pH was then adjusted to 4.0 with a 20% sulfuric acid solution to 0.
2 g of Quadrol (manufactured by BASF) was added. While stirring this with a homomixer at 3000 rpm,
A solution prepared by dissolving 20 g of the ingredients shown in the table in 30 g of chloroform (the pigment was dispersed) was added over 10 to 15 seconds, and emulsification was continued for 10 minutes.

The emulsion was transferred to a beaker of 500 ml and stirred for 1 to 2 hours using a stirring blade, and then the solvent was distilled off.

Next, 8.3 g of urea solution (50 wt%), 0.4 g of resorcinol dissolved in 5 g of water, 10.7 g of formalin (37%) and 0.6 g of ammonium sulfate dissolved in 10 mβ of water were added at 2 min intervals. I added it.

After raising the temperature to 60° C. and continuing stirring for 3 hours, the temperature was lowered and the pH was adjusted to 12.0 with a 20% caustic soda solution. After filtering this capsule liquid, it was heated twice at 1000 m℃.
This was washed with water and dried to obtain a microcapsule-shaped image forming element.

As shown in FIG. 1, this image forming element is a microcapsule in which a core 1c is covered with a shell 1d, and the particle size is 7 to 15.
μs, and the average particle size was 10 μm.

Next, a polyester adhesive (LP-022, manufactured by Nippon Gosei Kagaku Kogyo ■) was applied as an adhesive layer 1e to a thickness of about 1 μm onto the PET film lb as a support. An excess amount of the microcapsules was sprinkled onto the adhesive layer, and the excess microcapsules not attached to the adhesive were brushed off.

Next, these transfer recording media were pressed against each other at 1 kgf/cm2, and each roller was coated with silicone rubber having a hardness of 70 degrees on an aluminum roller with a diameter of 40 mm.
It was passed through at a speed of 00 mm and 74 min. Further, at this time, the surface temperature of each roller was maintained at 80°C. After passing between the rollers, the image forming element on the adhesive layer is firmly fixed to the PET film.

Through the above steps, a transfer recording medium 1 as shown in the schematic cross-sectional view of FIG. 1 was obtained.

(Evaluation of Sensitivity) Next, the transfer recording medium 1 produced by the above method was wound around a supply roll 2 in the form of a roll, and installed in the apparatus shown in FIG.

The thermal head 2 was an A4 size line type with 8 dots/mm and heat generating element rows arranged at the edge portion, and was pressed against the heat generating elements by the tension of the transfer recording medium 1. Then, chemical lamps 4 were placed at opposing locations. As the lamp 4, a lamp (manufactured by Toshiba, FL10A70B/33T15) with a peak wavelength of 450 nm was used, matching the sensitive wavelength range of the photopolymerization initiator.

Next, the heat generation of the thermal head 2 is controlled according to the image signal. This embodiment deals with a transfer recording layer whose softening temperature and transfer start temperature rise when exposed to light and heat, resulting in negative recording. That is, the thermal head 2 is controlled such that it does not energize when a mark signal (yellow) is present, but energizes and generates heat when it is not a mark signal (white).

The energizing energy during this heat generation is 0.8W/datX
m5ec, the thermal head 2 is controlled and driven by the control circuit 5 in accordance with the image signal in the manner described above while the lamp 4 uniformly irradiates X m5ec light in synchronization with the signal of the thermal head 2. / l ine
The recording medium was conveyed by a stepping motor and a drive rubber roll in synchronization with a repetition period of
O was superimposed on the transfer recording layer and conveyed while being sandwiched between a heat roll 8 and a pinch roll 9. Heat roll 8 is 300W
The heater 7 was controlled so as to maintain the surface at an arbitrary temperature in the range of 50 to 150° C. using an aluminum roll having a heater 7 inside and the surface of which was coated with silicone rubber of a double thickness. The pinch roll 9 was a silicone rubber roll with a hardness of 50 degrees as measured by the JIS rubber hardness meter, and the pressing force was 1 to 1.5 kg/cm2.

Controlling the heat roll 8 in the range of 110°C to 130°C,
After the plain paper was conveyed over the transfer recording layer, the support 1b was peeled off and the minimum time X m5ec during which an image was obtained was determined and defined as the sensitivity (X is 5, increased in increments of 5 below 1O1). That is, the smaller the value of X, the higher the sensitivity. Moreover, the obtained image was a high-quality image with good fixability.

This sensitivity evaluation was carried out immediately after the recording medium was prepared and after it had been stored at 60° C. for a certain period of time, and the results shown in Table 2 were obtained.

Mixing the second surface image forming element and the image forming element in equal amounts,
In the same manner as in Example 1, it was fixed on a PET substrate coated with an adhesive to produce a transfer recording medium (see FIG. 4).

Next, the transfer recording medium 1 produced by the above method was installed in the apparatus shown in FIG. However, Lamp 4 is Lamp A with a peak wavelength of 335 nm in accordance with the light absorption characteristics of the photopolymerization initiator.
(manufactured by Toshiba, F10A70B/33T15) and lamp B with a peak wavelength of 390 nm (manufactured by Toshiba, F10A70E39)
/33T15) were placed.

As shown in Table 2, it can be seen that the transfer recording medium of the present invention has excellent storage stability.

Next, an example will be shown in which a two-color image is formed using light energy and thermal energy using the image forming method described in JP-A-62-174195.

The compositions shown in Table 3 were prepared in the same manner as in Example 1 to form image forming elements in the form of microcapsules. Next, the image transfer recording layer 1a having a yellow hue obtained in Example 1 has the property that when light of a predetermined wavelength and heat are applied, the softening point temperature increases and it is no longer transferred to the recording paper. Because of having
As shown in the timing chart in Fig. 5, when recording yellow, the heating element of the heating element array of the thermal head corresponding to the yellow color of the image signal is not energized, and the heating element corresponding to the yellow color of the image signal is turned on to the white color of the image signal (the recording medium is white). A current of 15 m5 ec is applied to the corresponding portion, and at the same time, lamp A is uniformly irradiated for 17 m5 ec.

Next, for yellow recording, 23 seconds after the end of the lamp A irradiation.
After m5ec has elapsed, that is, 40m5 from the above-mentioned energization time.
After ec, a portion of the heating element of the thermal head corresponding to the yellow color of the image signal is energized for 30 m5 ec, and at the same time, lamp B is uniformly irradiated for 32 m5 ec.

As described above, the thermal head is controlled according to the image signals of magenta, yellow, and white, a negative image is formed on the transfer recording layer, and the image is transferred onto plain paper in the same manner as in Example 1, thereby achieving two-color recording. I was able to do it with a shot.

[Effects of the Invention] As explained above, the photopolymerizable composition of the present invention has excellent storage stability, and the recording medium of the present invention using this composition exhibits no deterioration in performance even during long-term storage. It is excellent with less.

[Brief explanation of drawings]

1 and 4 are configuration diagrams of the transfer recording medium of the present invention,
2 and 3 are schematic diagrams of an apparatus for performing transfer recording using the recording medium of the present invention, and FIG. 5 is a timing chart for two-color printing. 1...Recording medium la...Transfer recording layer 1b...Support lc, I
g, lh...core ld...shell 1e...
Adhesive layer 2... Thermal head 3... Image forming element 4...
・Lamp 5... Control circuit 6... Supply roll 7... Heater 8... Heat roll 9
... Pinch roll lO... Plain paper 11.
... Winding roll 12 ... Recorded image Fig. 1 Fig. 4 Fig. 9 Vinci roll

Claims (1)

[Scope of Claims] 1. A photopolymerizable composition containing a compound having an ethylenically unsaturated double bond and a photopolymerization initiator as essential components,
A photopolymerizable composition characterized in that the photopolymerization initiator is a polymer compound having a group having a photopolymerization initiating function in its side chain. 2. A recording medium having a transfer recording layer on a support whose physical properties governing the transfer characteristics change by simultaneously applying at least one kind of energy among light and thermal energy in correspondence with image recording information. The transfer recording layer is formed from an image forming element that is solid at room temperature and includes at least a coloring material and a sensitive component that is sensitive to application of light energy and thermal energy, and the sensitive component is 1. A transfer recording medium comprising the photopolymerizable composition according to 1.