JP3472945B2 - Thermochromic dry offset ink and printed decorative container using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermochromic dry offset ink and a printed decorative container using the same. More specifically, the present invention relates to a dry offset ink in which a reversible thermochromic pigment is dispersed in a vehicle, which has an excellent ink transfer property and gives a uniform printing effect, and a decorative container formed by printing using the dry offset ink.

[0002]

2. Description of the Related Art Conventionally, an electron-donating color-forming organic compound, an electron-accepting compound that develops the electron-donating color-forming organic compound, and a polar group that controls the temperature at which the color reaction of both of them develops. A thermochromic pigment obtained by microencapsulating a reversible thermochromic material comprising three components of a medium compound having
It has been used as a screen printing ink, a gravure printing ink, etc. after being dispersed in an appropriate vehicle to form an ink. There have also been some attempts to apply thermochromic pigments to offset printing inks, but the roll-to-roll ink transfer characteristic of offset printing machines is extremely poor, and as the printing speed increases, the transfer of thermochromic pigments As a result, the vehicle component preferentially transfers between rolls,
It was difficult to obtain a stable and uniform printing effect, and the sheet-fed offset printing that was printed at a low speed was slightly possible.

However, in recent years, due to various improvements in dry offset plates, dry offset printing has become popular, and in particular, the outer surface of containers having a curved surface is dried at a very high speed by a curved surface printing method. Offset printing has started. For example, metal cans for beverages or food, decoration on containers that are printed in large quantities such as plastic cans, in consideration of production efficiency and cost, the dry offset curved surface printing method is adopted,
It is produced at a high speed of 200 to 600 pieces / minute in the case of a resin container and 500 to 1500 pieces / minute in the case of a metal can for beverage.

As an application example of direct printing of a conventional thermochromic pigment, there is a method by curved surface screen printing.
Due to the printing method, the printing speed is low, and the printing speed is limited to 100 times per minute at the most, and it is possible for the conventional technology to cope with containers produced at several times to several tens of times the speed. could not. Further, when a conventional thermochromic offset ink was applied to such a field, it was practically impossible to transfer the thermochromic pigment together with the medium to the printing medium smoothly with a uniform density. Moreover, regarding the suitability for long-term continuous printing with the conventional thermochromic offset ink, there was a phenomenon in which some of the microcapsules were broken at the roll kneading site of the offset printing machine. This phenomenon is related to the strength of the microcapsule itself, but the main cause is that the microcapsule wall membrane is destroyed by repeatedly receiving roll pressure on the roll for a long time because of poor transferability. It is considered that When such a phenomenon occurs, the thermochromic function is of course deteriorated,
The organic compound in the microcapsule particles diffuses into the vehicle, and the vehicle has a tack value, DM
The vehicle characteristics such as (diameter) value are deteriorated, which causes deterioration of continuous printability for a long time.

[0005]

DISCLOSURE OF THE INVENTION The present inventor has improved the transferability between rolls of conventional offset inks containing a thermochromic pigment, and can stably obtain a uniform printing effect. In addition, it is intended to provide a dry offset ink that does not deteriorate the microcapsules even during long-term continuous printing and that satisfies the printability of a curved surface container having excellent transferability, and a printing decoration container using the same. is there.

[0006]

The present invention provides an electron donating property.
Chromatic organic compound, electron-accepting property for coloring the compound
The temperature at which the compound and the color reaction of both of them occur are controlled.
It can consist of three essential components of a medium compound having a polar group
Reverse thermochromic composition, epoxy resin or isocyanate
In the thermochromic pigment encapsulated in the resin microcapsules and the ink composed of the medium for dry offset ink, the thermochromic pigment having a particle distribution in the range of 0.5 μm to 5.0 μm is a total thermochromic pigment. The thermochromic dry offset ink is characterized in that it is dispersed in the medium in an amount of 90% by volume or more. Furthermore, the thermochromic pigment has an average particle diameter of 1.0 μm to 4.0.
A thermochromic dry offset ink in the range of μm, and further a spacer selected from thermosetting resin fine powder, thermoplastic resin fine powder and inorganic fine powder having a particle size larger than the average particle size of the thermochromic pigment. One or two or more fine powders that perform the function, and 5 to 2 relative to the solid content of the thermochromic pigment.
0 is the weight percent of the thermochromic dry offset ink formed by mixing in a range, in a further, the curved dry offset printing machine container surface, electron-donating coloring organic compound,
An electron-accepting compound that causes the compound to color, and both
The polar group that controls the temperature of the color reaction
Reversible thermochromic composition consisting of three essential components
Is made of epoxy resin or isocyanate resin
Encapsulated particles with particle distribution of 0.5 μm to 5.0
The thermochromic pigment in the range of μm is 90% of the total thermochromic pigment.
Accounted for more than% by volume thermochromic print layer formed is fixed in a dispersed state in Mejiumu is to print pressurized Kazariyo device requirements provided.

As the thermochromic pigment, an electron-donating color-developing organic compound, an electron-accepting compound that causes the compound to color, and a medium compound having a polar group that controls the temperature at which the color reaction of both of them occurs. reversible thermal discoloration composition use Irare consisting three components of, for these compositions, JP-B 51-44706, JP-Sho 51-44709
Japanese Patent Publication, Japanese Patent Publication No. 1-29398, Japanese Patent Publication No. 4-17
Examples thereof include the compositions described in Japanese Patent No. 154, etc.

[0008] These thermochromic compositions exhibit reversible thermochromism having a desired color change temperature in the temperature range of about -50 ° C to + 100 ° C, depending on the selection of the above-mentioned medium compound, and among them, color change due to temperature change. Also included is a quasi-reversible thermochromic composition having a hysteresis characteristic in which the color changes when a temperature rises from a temperature lower than the temperature range and when a temperature decreases from a temperature higher than the color change temperature region.

[0009] The thermochromic composition by known microencapsulation method in an aqueous medium, is used as the thermochromic pigment micro capsule Le form.

The inventor of the present invention has developed a thermochromic offset ink prepared by mixing the thermochromic pigment with an offset printing ink vehicle. However, the conventional thermochromic pigment, that is, a wide particle distribution (2 μm to 2 μm) has been developed. (30 μm), the thermochromic pigment having a particle size of more than 5 μm in the particle distribution of the thermochromic pigment has a roll-to-roll ink transfer property peculiar to the offset machine. We obtained the knowledge that it was difficult to follow. Further, as a result of further study, such coarse particles have poor transferability between rolls and have a large tendency to accumulate on the rolls. It was found that there is also an effect of remarkably impairing the transfer to the roll.

Originally, the coloring pigment contained in the general offset printing ink is one of the ink manufacturing processes.
It is preferably finely dispersed to a submicron order or less by a fine dispersion process such as a main roll treatment process and a roll mill treatment process. In the case of a thermochromic pigment, the thermochromic pigment is easily destroyed when such a roll treatment is performed, and therefore the capsule wall material is encapsulated with a thermosetting resin, or is solid-solubilized, or is formed into a composite film. In view of the hardness of the inclusion itself, the roll treatment should usually be avoided.
Therefore, the particle size or particle size distribution of the thermochromic pigment for offset printing is preferably set in the microencapsulation stage.

Another limitation of the thermochromic pigment is that if the particle size of the microcapsules is set to submicron or less, isolation of the capsules after the microencapsulation step will be greatly hindered. That is, the thermochromic pigment finely encapsulated in a state of being suspended in an aqueous medium can be obtained, but efficient isolation by means such as filtration or centrifugation is difficult.

The present inventor considers such factors and
Furthermore, regarding the ink transfer from roll to roll on an offset printing machine, the condition that the ink film thickness on the blanket roll varies depending on the amount of ink supplied to the ink reservoir, but is approximately between 2 μm and 10 μm is also taken into consideration. Then, the particle size of the thermochromic pigment was examined in consideration of the printing effect of the ink using the pigment.

As a result of further study, when the ratio of coarse particles exceeding 5.0 μm exceeds 10% by volume of the total thermochromic pigment particles, the initial density of the printed matter tends to decrease according to the ratio. As the continuous printing is performed, the density gradually decreases, and finally, it becomes impossible to obtain a sufficient density. For ink that has such a phenomenon, after printing,
As a result of cleaning the roll with a cleaning solvent, a large amount of coarse particles exceeding 5 μm accumulated in the roll contact portion. As is clear from the above results, in the roll-to-roll ink transfer, when the pigment particle size is larger than a certain value, the roll-to-roll transfer of the ink does not proceed smoothly and the accumulability exceeds the transferability.

Based on such knowledge, the present inventor has found that the particle size distribution of the offset ink containing the thermochromic pigment is 0.5 μm to
When 90% by volume or more of the total thermochromic pigment particles is included in the range of 5.0 μm, the ink can be smoothly transferred to the printed matter with the transferability exceeding the accumulative property between the rolls of the thermochromic pigment. As a result, it has been possible to make a great improvement in the continuous printability and high-speed printability of conventional offset inks containing thermochromic pigments.

Further, in high-speed dry offset printing, a more rapid roll-to-roll transition is required. Therefore, it is more preferable that the offset ink containing a thermochromic pigment has a total heat distribution in the range of 0.5 μm to 4.0 μm. A configuration containing 90% by volume or more of the color-changing particles is suitable.

As the method for producing the thermochromic pigment, the various encapsulation methods described above are applied. In order to satisfy the particle conditions of the present invention, the encapsulating liquid containing the thermochromic composition is placed in an aqueous medium. Emulsify or disperse into, and set to the desired particle size. Usually, in order to further narrow the particle distribution, and to prevent the generation of coarse particles, water-soluble acrylic resin, polyvinyl alcohol, ethylene-water-soluble polymer such as maleic anhydride copolymer resin, gum arabic, hydroxypropyl cellulose, By using a water-soluble cellulose derivative such as sodium alginate or methyl cellulose, a water-soluble protein such as gelatin or albumin, a surfactant or an emulsifier, it is possible to set the particle distribution in a narrow range.

Regarding the encapsulation method, in order to obtain the thermochromic pigment having a narrow particle size distribution of the present invention, aggregation,
An interfacial polymerization method or an interfacial polycondensation method, which hardly causes coalescence, is preferably used. Further, after the completion of the encapsulation, the capsule liquid is diluted with water as desired, and the coarse particles in the present invention are roughly removed by filtering the contaminants and the coarse particles using filters. As filters, stainless steel mesh, synthetic resin monofilament mesh, synthetic resin multifilament mesh, ultrafine fiber filter, cotton cloth,
Industrial filter materials such as non-woven fabric, needle felt, and paper are used alone or in appropriate combination.

The thermochromic pigment dispersion liquid from which the coarse particles have been filtered out is used for the purpose of further isolating the thermochromic pigment by a centrifugal separation method or a filtration method to obtain a water content of 30% by weight to 50% by weight.
Of water-containing thermochromic pigment. The water-containing thermochromic pigment is further mixed with the vehicle for offset ink and uniformly dispersed in the vehicle. In this process, the water retained by the thermochromic pigment is removed by a flushing method, a decompression method or the like.

Examples of the resin used in the vehicle for offset ink in which the thermochromic pigment is dispersed include the following. Non-drying oil alkyd resin, semi-drying oil alkyd resin, drying oil alkyd resin, urethane modified alkyd resin, styrene modified alkyd resin, acrylic modified alkyd resin, epoxy modified alkyd resin, phenol modified alkyd resin, oil-free alkyd resin, acid-cured amino Examples thereof include alkyd resins, rosin-modified alkyd resins, rosin-modified phenolic resins, rosin-modified maleic acid resins, acrylic resins, acrylic polyols, epoxy resins and epoxy-modified alkyd resins.

The above resins can be used alone or in combination of two or more, and are usually available as a medium dissolved in a solvent and oils. Examples of the solvent include industrial solvent, kerosene, kerosene, Solvesso 100, from the viewpoint of the on-press stability of the ink in offset printing.
Solvesso 150, xylene, mineral spirits, n
-A relatively slow-drying solvent such as butanol, anone, isophorone, cellosolves, cellosolve acetates is used.

Further, the resin or medium may be crosslinked as desired. Usually, in the case of a baking type, an amino resin such as butylated urea resin, butylated urea melamine resin, butylated melamine resin, butylated benzoguanamine resin is blended as a cross-linking agent, a metal drier is added, or an isocyanate type is used. Crosslinking agents can be added to crosslink at elevated or moderate temperatures.

Further, an ultraviolet curable medium and an electron beam curable medium can also be applied to the present invention, and the following prepolymers, oligomers and monomers can be used in combination as desired. To do.

Photopolymerizable prepolymers such as epoxy acrylate, urethane acrylate, oligoester acrylate, and polyester acrylate as the acrylate radical polymerization type. A relatively low viscosity acrylate compound having a molecular weight of 100 to 800 classified as a photopolymerizable monomer or a diluting monomer, for example, 2-ethylhexyl acrylate, butanediol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, 1,6-hexane. Diol diacrylate, neopentyl glycol diacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, neopentyl glycol acrylic acid benzoate, 2-acryloyloxyethyl acid phosphate Fate, 2-hydroxyethyl acrylate, isooctyl acrylate, benzyl acrylate, etc. It is below.

Acrylate media are used by combining the above materials as desired, and further adding a photoinitiator and a sensitizer. As the cationic polymerization type,
Cationic polymerization type media that combine a liquid epoxy resin and an initiator that generates a proton or an acid upon irradiation with light can be used. Other applicable photocurable media include ene-thiol addition reaction media.

The dry offset medium may further contain, if desired, a thixotropic agent, an extender pigment, a general solvent for dilution, an antioxidant, an ultraviolet absorber, a polymerization inhibitor for stabilizing in the dark, and A polymerizable polymer, a leveling agent, a defoaming agent, an adhesion imparting agent and the like can be appropriately added.

The mixing ratio of the thermochromic pigment and the above-mentioned mediums is such that, in the state of the ink after dehydration, the thermochromic pigment has a solid content based on 100 parts by weight of the medium including all the crosslinking agent, solvent and additives. 10 to 40 parts by weight, preferably 15 to 35 parts by weight of the thermochromic pigment. If the thermochromic pigment exceeds 40 parts by weight, the physical properties of the ink required for the offset ink, particularly the tack value and DM value, decrease,
Ink transferability is reduced. Also, the thermochromic pigment is 10
When the amount is less than the amount by weight, the ink transfer property is good, but a good printing effect cannot be obtained because the pigment density is low.

Further, the present inventor has added to the ink fine particles having a particle size larger than the average particle size of the thermochromic pigment and being hard and not destroyed even when kneading between printing rolls. It has been found that the thermochromic pigment is stably printed without being destroyed or deteriorated even in continuous printing for a long time. The fine particles are preferably made of a material having a size slightly larger than the average particle size of the thermochromic pigment, and those having a more uniform distribution with a maximum size not exceeding 10 μm are applied. The fine particles act as a constant spacer in the ink kneading on the roll of the offset printing material, and alleviate the pressure between the rolls being directly applied to the thermochromic pigment. The stability can be significantly improved.

As the fine particles satisfying such a function, a material selected from a thermosetting resin fine powder and an inorganic fine powder can be used, and it is 5 to 20 relative to the solid content of the thermochromic pigment.
By adding in the range of wt%, the intended purpose can be achieved.

As the thermosetting resin fine powder, there are melamine resin, benzoguanamine resin, urea melamine resin, epoxy resin, crosslinked acrylic resin, crosslinked styrene resin, unsaturated polyester resin, silicone resin, urethane resin and the like. Examples of the fine powder include nylon resin, polyester resin, polypropylene resin, polyethylene resin, styrene resin, acrylic ester resin, methacrylic ester resin, vinyl chloride resin and the like.

Examples of the inorganic fine powder include silica, alumina, calcium carbonate, barium carbonate, magnesium carbonate, inorganic hollow fired bodies, glass beads, boron nitride, zinc oxide, tungsten oxide and the like.

As the fine powder, those having an average particle diameter not exceeding the maximum diameter of 10 μm and slightly exceeding the average particle diameter of the thermochromic pigment are used, but those having a particle diameter smaller than the average particle diameter of the thermochromic pigment are partially used. There is no problem even if it is included. The fine powder can meet the requirements of the present invention by being refined as necessary by means such as classification and filtration so that coarse particles of 10 μm or more are not mixed in advance. Even in the case of spacer particles, it is also not preferable that coarse particles are often mixed in the ink in terms of ink transfer property. Therefore, more preferably, the average particle size of the thermochromic pigment is slightly larger than that of the thermochromic pigment, and the volume percentage of the particles having a particle size of more than 5 μm is 10% or less.

Next, a printed decorative container using the thermochromic dry offset ink of the present invention will be described. The dry offset ink having thermochromic property obtained by the present invention can be applied to sheet-like materials such as paper, synthetic paper, and film, but in particular, for dry offset printing of curved surface printing method that is printed at high speed, The effect can be exhibited. Examples of containers printed by such a method include aluminum cans formed by drawing, plastic containers formed by injection molding, foam containers formed by compression molding, glass containers, and the like. Usually, such containers have a cylindrical shape or a truncated cone shape, and printing is performed on the side surface thereof.
The dry offset ink having thermochromic property is printed by a printing machine having a plurality of units alone or in combination with a general ink, but the dry offset ink having a thermochromic property is arranged in a plurality of units,
It is also possible to increase the print density by performing overprinting. The containers printed by such a method are usually further coated with a top coat, which plays a role of physically protecting the printed surface, imparting appearance gloss, and imparting light resistance.

[0034]

[Function] The thermochromic pigment has a particle distribution of 0.5 μm to 5.0
Since all thermochromic pigment particles in the range of μm occupy 90% by volume or more and are dispersed in the medium, the intercolor ink transfer of the thermochromic pigment between the printing rolls is properly performed, and the pigments are dispersed between the rolls. The high-speed dry offset printing aptitude is satisfied without causing inadvertent accumulation of.

Further, the thermochromic pigment accounts for 10 to 40% by weight based on the solid content of the medium with respect to 100 parts by weight of the medium, thereby satisfying a suitable ink concentration and ink properties suitable for printing.

Further, by adding a spacer fine powder having an appropriate particle size, it is possible to alleviate that the pressure between the rolls during the ink kneading on the rolls of the offset printing machine is directly added to the thermochromic pigment, and It contributes to the formation of print-decorated containers which improve the stability and prevent the thermochromic pigment from being destroyed or deteriorated during continuous printing for a long time and effectively exhibiting the thermochromic effect.

[0037]

EXAMPLES Next, specific examples will be shown. The parts in the examples are parts by weight. Example 1 6- (Ethylisobutylamino) benzofluorane 5
Part, bisphenol A 10 parts, myristyl alcohol 3
A thermochromic composition consisting of 0 part and 20 parts of decyl myristate and 10 parts of an epoxy resin were heat-dissolved, and an inclusion solution was emulsified with an aqueous protective colloid medium. The emulsified particle diameter was determined by adjusting the stirring power of the homomixer so that 90% by volume or more of all particles were distributed in the range of 2.0 μm to 3.0 μm. Then, a water-soluble aliphatic modified amine curing agent was added, and microcapsules were formed by an interfacial polymerization method. The reaction temperature for microencapsulation was 80 ° C. for 10 hours. After the reaction, the obtained microcapsule suspension was filtered by stacking two sheets of 635 Mesh stainless steel, and then the thermochromic pigment was isolated by centrifugation to obtain a thermochromic pigment having a water content of 35%. .

The thermochromic pigment thus obtained was subjected to centrifugal sedimentation type automatic particle size distribution measuring apparatus (CAPA-300 manufactured by Hikiba Seisakusho Co., Ltd.) to measure the particle size distribution. The relationship of volume% [shown in ()] is D <0.
5 μm (2%), 0.5 ≦ D <2.0 (8%), 2.0
≦ D <3.0 (73%), 3.0 ≦ D <4.0 (10
%), 4.0 ≦ D <5.0 (3%), D> 5.0 (4.%).
0%), and a particle size distribution having an average particle size of 2.5 μm was obtained. or,
It was confirmed that 94% of the thermochromic pigment was in the range of 0.5 μm to 5.0 μm.

Next, 40 parts of a water-containing thermochromic pigment,
A thermochromic UV-curable dry offset ink was obtained by kneading 100 parts of a UV-curable dry offset medium (manufactured by Toyo Ink, UV carton medium) under reduced pressure for 8 hours. The ink is applied to a curved surface printing type dry offset printing machine, at a speed of 450 pieces per minute, a blank character "drinking" is printed on the outer peripheral surface of a polystyrene container, and then by a high pressure mercury lamp of 80 W / cm, The ink was cured by irradiating it with light at an irradiation distance of 8 cm for about 1 second.
The transferability of the ink was good from the start of printing, and the density of the printed matter after 1 hour was not changed as compared with the initial printed matter.
The temperature of the printed plastic container is approximately 12 ° C.
It was pink below and colorless at about 18 ° C or higher.

Example 2 4- (2-chloroaniline) -6-dibutylaminofluorane, 4 parts, 1,1-hexylidenebisphenol 12
Parts, n-butyl stearate 30 parts, palmitic acid n-
A thermochromic composition comprising 20 parts of butyl and 2 parts of TINUVIN 328 (made by Ciba-Geigy, an ultraviolet absorber), 15 parts of an aromatic isocyanate resin, and 20 parts of ethyl acetate as a cosolvent, and uniformly dissolved at 70 ° C. The solution was emulsified in a 15% aqueous solution of gum arabic (70 ° C). 90% by volume or more of all particles have an emulsified particle size of 1.0 μm to 2.0 μm.
The stirring power of the homomixer was adjusted so as to be distributed in the. After emulsification, stirring was continued for 1 hour, then 5 g of water-soluble aliphatic modified amine was added, and stirring was continued for further 5 hours. After the reaction, the resulting microcapsule suspension was diluted with 5 times the amount of water, filtered with a 400 Mesh stainless steel filter, and then with a cotton cloth. Then, the thermochromic pigment was isolated by a centrifugation method to obtain a water content of 33%.
% Thermochromic pigment was obtained.

The particle size distribution of the obtained thermochromic pigment was measured by the same method as in Example 1, and as a result, D <0.5 μm (7
%), 0.5 ≦ D <2.0 (62%), 2.0 ≦ D <
3.0 (17%), 3.0 ≦ D <4.0 (8%), 4.
A particle size distribution of 0 ≦ D <5.0 (2%), D> 5.0 (1%) and an average particle size of 1.4 μm was obtained. It was also confirmed that 96% of the thermochromic pigment was in the range of 0.5 μm to 5.0 μm.

Then, 45 parts of a water-containing thermochromic pigment,
Soybean oil modified alkyd resin (nonvolatile content 50%, solvent No. 5 solvent) 65 parts, butylated melamine resin (nonvolatile content 6
35 parts of 0% solvent Solvesso 150) was uniformly dispersed and kneaded in a kneader, and kneaded for 8 hours while removing water under reduced pressure to obtain a thermochromic baking-type dry offset ink.

The above ink was applied to a curved surface printing type dry offset printing machine, and printing was performed at a speed of 1000 pieces per minute on the entire side surface of a white coated can of a deep-drawn aluminum can. Then, baking was performed at 165 ° C. for 5 minutes. The transferability of the ink to the can was good from the start of printing, and the density of the printed matter after 2 hours was not changed at all as compared with the initial printed matter.
After another hour, the roll of the printing machine was washed with a solvent, and no accumulation of thermochromic pigment was found in the roll gap. When the aluminum can obtained as described above was filled with drinking water and cooled in a refrigerator (refrigerator temperature 7 ° C.), the color changed to black. It remained black even after it was taken out to room temperature (25 ° C) and left for a while, but when the drinking water in the contents was gradually reduced, the part that turned white from the upper end turned downward correspondingly. When the contents were completely lost, the entire surface became white, indicating that it has the function of a level gauge. The thermochromic pigment itself had a discoloration temperature of black at 10 ° C or lower and colorless at 13 ° C or higher.

[0044]

[0045]

[0046]

[0047]

Next, a comparative example will be shown. The parts in the comparative examples are parts by weight. Comparative Example 1 The stirring power of the homomixer in Example 1 was adjusted to emulsify so that the average particle size was about 4 μm, and by the same operation as in Example 1, a thermochromic pigment having a water content of 35% was obtained. Obtained.

As a result of measuring the particle distribution of the obtained thermochromic pigment, D <0.5 μm (0%), 0.5 ≦ D <2.0
(4%), 2.0 ≦ D <3.0 (11%), 3.0 ≦ D
<4.0 (26%), 4.0 ≦ D <5.0 (39%),
D> 5.0 (20%) and a particle size distribution with an average particle size of 4.7 μm were obtained. Further, 80% of the thermochromic pigment is 0.5 μm to 5.0 μm.
It was confirmed that it was in the range of m.

When an ink was formed in the same manner as in Example 1 and printed, some good ink transfer was observed for about 5 minutes from the start of printing, but thereafter, the ink transfer property decreased with the passage of time. After 30 minutes, the printing density decreased to about 50% of the initial printed matter, and at the same time, the smoothness and uniformity of the printed surface deteriorated. When the printing press roll was washed with a solvent, thermochromic pigment particles of 3.5 μm to 10 μm were accumulated on the roll.

Comparative Example 2 By adjusting the stirring power of the homomixer in Example 1, emulsification was performed so that the average particle size was about 7 μm, and by the same operation as in Example 1, thermal discoloration with a water content of 35% was performed. A sex pigment was obtained.

As a result of measuring the particle distribution of the obtained thermochromic pigment, D <0.5 μm (0%), 0.5 ≦ D <2.0
(0%), 2.0 ≦ D <3.0 (4%), 3.0 ≦ D <
4.0 (7%), 4.0 ≦ D <5.0 (10%), D>
A particle size distribution of 5.0 (79%) and an average particle size of 8.0 μm was obtained. Further, 21% of the thermochromic pigment is 0.5 μm-
It was confirmed to be in the range of 5.0 μm.

When an ink was formed and printed by the same method as in Example 1, almost no ink transfer was observed from the start of printing, and only the vehicle component was printed on the container. When the printing press roll was washed with a solvent, a large amount of the thermochromic pigment was accumulated on the roll, especially in the roll near the ink reservoir.

The print density and continuous stable printability of the thermochromic pigments of the above-mentioned Examples and Comparative Examples are shown.

[Table 1] The symbols in the table are as follows. Printed matter density (visual judgment of initial printed matter, but if the color change temperature is below room temperature, it is judged when the thermochromic pigment is in a color development state) ◎: Dark ○: Generally dark △: Light x: Continuous without density Stable printability (visually comparing the difference in density between the initial printed matter and the printed matter after 1 hour) ◎: The density of the printed matter after 1 hour is completely different from the density of the initial printed matter. ○: The density of the printed matter after 1 hour is initial. There is almost no difference from the density of the printed matter. ×: The density of the printed matter after one hour is significantly different from the density of the initial printed matter (1/2 or less).

[0055]

INDUSTRIAL APPLICABILITY The thermochromic dry offset ink of the present invention is an electron-donating color-developing organic compound, which produces a coloration of the compound
The electron-accepting compound to be used, and the color reaction of both of them.
It is necessary to use a medium compound having a polar group to control the temperature
Reversible thermochromic composition consisting of three components
Or encapsulated in microcapsules made of isocyanate resin
It is an ink consisting of a thermochromic pigment and a dry offset ink medium, and by specifying the particle size distribution of the thermochromic pigment as described above, curved surface printing printed at high speed, which was previously impossible Method dry offset printing has become possible. Furthermore, by coexisting an appropriate amount of fine powder slightly exceeding the particle diameter of the thermochromic pigment with respect to the thermochromic pigment, destruction and deterioration of the thermochromic pigment in continuous printing can be prevented, so that stable printing can be performed for a long time. It has become possible. Container printed decoration according to the present invention thermochromic dry offset ink, a beverage filled in the container, food, pharmaceutical, is effectively applied to an appropriate temperature to critical temperature display of packing cosmetics.

Claims (5)

(57) [Claims] 1. An electron-donating color-forming organic compound, said compound
Electron-accepting compound for coloring things, and coloring of both
Use of a polar group as a medium to control the temperature at which the reaction occurs
A reversible thermochromic composition consisting of three essential components
Microcapsules made of xy resin or isocyanate resin
And thermochromic pigments being incorporated into a, Ri Do from the dry offset ink for Mejiumu, the particle distribution 0.5μm~5.0μ
A thermochromic dry offset ink, wherein the thermochromic pigment in the range of m occupies 90% by volume or more of the total thermochromic pigment and is dispersed in the medium. 2. The thermochromic pigment has an average particle size of 1.0 μm.
The thermochromic dry offset ink according to claim 1, which is in the range of m to 4.0 μm. 3. One or more fine powders having a spacer function selected from thermosetting resin fine powders, thermoplastic resin fine powders and inorganic fine powders having a particle size larger than the average particle size of the thermochromic pigment. 5 to the solid content of the thermochromic pigment
The thermochromic dry offset ink according to claim 1 or 2, which is blended in a range of 20% by weight. 4. The thermochromic dry offset ink according to claim 1, 2 or 3, wherein the thermochromic pigment accounts for 10 to 40% by weight based on the solid content of the medium with respect to 100 parts by weight of the medium. 5. Curved surface dry offset printing on the container surface
Machine, electron donating color-forming organic compound, said compound
Electron-accepting compound that causes the coloration of
Media compounds with polar groups that control the temperature of reaction
A reversible thermochromic composition consisting of the essential three components of
For microcapsules made of resin or isocyanate resin
Encapsulated particle distribution range of 0.5 μm to 5.0 μm
Is 90% by volume or more of the total thermochromic pigment
Discolored by occupying the core and being fixed in a dispersed state in the medium
Decorative container provided with a transparent printing layer.