JP2002144694A - Method for printing heat shrinkage label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for printing capable of forming a heat shrinkage label having an image including a high quality, toughness and excellent label mounting suitability by printing on a heat shrinkage film. SOLUTION: The method for printing the heat shrinkage label comprises the steps of forming an image by using an electrophotographic toner for flash fixing on the heat shrinkage film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method for printing a heat-shrinkable film to form a heat-shrinkable label.

[0002]

2. Description of the Related Art A printing method for producing a heat-shrinkable label by forming an image on a heat-shrinkable film has hitherto been known as gravure printing (Japanese Patent Application Laid-Open Nos. 5-104686 and 2000-2).
35843), screen printing (Japanese Unexamined Patent Publication No.
No. 48170). However, these printings require high skills, require time and cost to prepare a printing plate, and use a solvent-based ink that is environmentally unfavorable. In recent years, the demand for on-demand printing, which enables variable printing when desired, in a desired amount, has been increasing, and a printing method using a plate such as gravure or screen printing has been able to meet this demand.

On the other hand, the flash fixing of electrophotographic toner described in Japanese Patent Application Laid-Open No. 11-38667 has the advantage of not restricting the medium to be printed as a non-contact fixing method, and its application to label printing and the like has been suggested. However, no specific example applied to heat shrink label printing has been described.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing method capable of printing on a heat-shrinkable film to produce a heat-shrinkable label having an image having high quality, toughness, and excellent label mounting suitability.

[0005]

The above object of the present invention is achieved by the following means.

[0006] 1. A method for printing a heat-shrinkable label, comprising forming an image on a heat-shrinkable film using an electrophotographic toner for flash fixing.

[0007] 2. 2. The method for printing a heat shrinkable label according to the above item 1, wherein the electrophotographic toner for flash fixing contains a polymerized toner.

[0008] 3. 2. The method for printing a heat-shrinkable label according to the above 1, wherein the electrophotographic toner for flash fixing contains a slipping agent.

4. 2. The method for printing a heat-shrinkable label according to the above 1, wherein the electrophotographic toner for flash fixing contains an infrared absorbing material.

[0010] 5. 800-1100nm infrared absorption material
5. The method for printing a heat-shrinkable label according to the item 4, wherein the dye is an infrared-absorbing dye having an absorption peak in the visible region and having substantially no absorption in the visible region.

Hereinafter, the present invention will be described in detail. In the method of forming a heat-shrinkable label by forming a printed image on a heat-shrinkable film, the image is formed using an electrophotographic toner for flash fixing, so that the heat-shrinkable film is high-quality, tough and label-attached without denaturation. An image with excellent suitability can be formed. In addition, it is possible to perform variable printing when desired, in a desired amount, that is, to perform on-demand printing.

As the heat-shrinkable film used in the present invention, any conventionally known heat-shrinkable films can be used. Specifically, polyvinyl chloride, polypropylene, polystyrene,
A heat-shrinkable film obtained by uniaxially or biaxially stretching a material such as polyester can be exemplified.

The heat-shrinkable label refers to a label on which a desired image is formed on the heat-shrinkable film by printing on the heat-shrinkable film, which is shrunk and attached to a container such as a PET bottle.

[0014] Compared with the methods requiring high skills, which are conventionally performed by gravure printing and screen printing, the method using the electrophotographic toner for flash fixing is simple in image formation by using an electrophotographic method without using a printing plate or the like. In addition to being able to fix an image on a heat-shrinkable film by using a flash fixing method, that is, by heating the toner itself, for example, by absorbing infrared rays, the image can be fixed without contacting a heating member. No heat history is given, and film deformation is small. Therefore, when used as a heat-shrinkable label, wrinkles are less likely to occur even after finishing by shrinking by printing and heating, and the fixed image has high robustness (strongly fixed) and has a beautiful finish.

[0015] Also, there is a feature that variable printing can be performed in a desired amount at a desired time without using a solvent-based ink that is environmentally unfavorable (on-demand printing). <Electrophotographic Toner for Flash Fixing> The binder resin used in the flash fixing toner in the present invention is not particularly limited, and examples thereof include polystyrene, styrene and (meth) acrylate, acrylonitrile or maleate. With styrene-containing copolymers, poly (meth) acrylates,
Examples include polyester-based, polyamide-based, epoxy-based, phenol-based, hydrocarbon-based, and petroleum-based resins. These resins can be used alone or in combination of two or more, and further other resins and additives can be used in combination. In the present invention, a polymerized toner (described later) is suitably used.

As the coloring agent, any conventionally known coloring agents can be used. For example, black coloring agents such as carbon black, furnace black and acetylene black, graphite, cadmium yellow, yellow iron oxide, titanium yellow, chrome yellow, Yellow colorants such as naphthol yellow, hansa yellow, pigment yellow, benzidine yellow, permanent yellow, quinoline yellow lake, anthrapyrimidine yellow, permanent orange, molybdenum orange,
Orange colorants such as Vulcan fast orange, benzidine orange, indanthrene brilliant orange, brown colorants such as iron oxide, amber, permanent brown, bengala, rose bengala, antimony powder, permanent red, fire red, brilliant carmine, light fast Red toner, permanent carmine, pyrazolone red, Bordeaux, Helio Bordeaux,
Red coloring agents such as rhodamine lake, Dupont oil red, thioindigo red, thioindigo maroon, watching red strontium, purple coloring agents such as cobalt purple, fast violet, dioxane violet, methyl violet lake, methylene blue, aniline blue, cobalt blue, Blue colorants such as Cerulean Blue, Calco Oil Blue, Metal-Free Phthalocyanine Blue, Phthalocyanine Blue, Ultramarine Blue, Indanthrene Blue, Indigo, Chrome Green,
Pigments or dyes such as green colorants such as cobalt green, pigment green B, green gold, phthalocyanine green, malachite green oxalate, and polychrome bromide copper phthalocyanine can be exemplified, and these pigments or dyes can be used alone or in combination. Can be used.

Although not particularly limited, these colorants are preferably used in an amount of 3 to 15 parts by mass per 100 parts by mass of the binder resin in the toner composition.

The flash fixing toner of the present invention may further contain, if necessary, additives such as a charge control agent, a fluidizing agent and a slipping agent.

Examples of the charge controlling agent include nigrosine, monoazo dye, zinc, hexadecyl succinate,
Alkyl esters or alkylamides of naphthoic acid,
Examples thereof include nitrohumic acid, N, N-tetramethyldiaminebenzophenone, N, N-tetramethylbenzidine, triazine, and salicylic acid metal complex. In the form of a color toner in which the colorant used in the flash fixing toner of the present invention is other than black, the charge control agent is preferably colorless or pale.

Examples of the fluidizing agent include inorganic fine particles such as colloidal silica, hydrophobic silica, hydrophobic titania, hydrophobic zirconia, and talc, and organic fine particles such as polystyrene beads and (meth) acrylic resin beads. Can be used.

The method for producing the flash fixing toner of the present invention is not particularly limited, and a binder resin, a colorant, an infrared absorber (described later) and other additives to be added as required are added in predetermined amounts. After melt-kneading, cooling and pulverizing, classifying to obtain toner particles by melt-kneading method,
Alternatively, in the monomer that forms the binder resin by polymerization,
A suspension polymerization method for obtaining toner particles by suspending a polymerizable composition containing a colorant, an infrared absorber and the like in an aqueous medium and polymerizing the monomer, and various other known production methods Can be adopted.

The flash fixing toner according to the present invention obtained as described above has an average particle size, for example, depending on the resolution and the like aimed at in the electrophotography.
The thickness is about 5 to 15 μm, more preferably about 5 to 10 μm. These are volume average particle diameters, for example, a laser diffraction particle size distribution analyzer SA manufactured by Shimadzu Corporation.
It can be measured using LD-1100 or the like.

The toner of the present invention is used as a developer mixed with a carrier. As the carrier used in the present invention, a carrier obtained by coating a conventional resin such as iron or ferrite with a core material is used. The material of the resin is preferably any of methyl silicon, amine-added methyl silicon, phenyl silicon, modified silicone, melamine cross-linked acryl, and fluorinated acryl. The chargeability of the toner can be controlled by adjusting the material and the thickness of the resin coated on the carrier.

In the present invention, the volume average particle size of the carrier particles is preferably 20 to 120 μm, more preferably 40 to 100 μm.

In the electrophotographic developer of the present invention comprising such toner particles and carrier particles, the content of the toner is preferably 2 to 12% by mass, more preferably 3 to 8% by mass. .

As the slipping agent, conventionally known waxes and polyolefins are used. As the wax component, a polyolefin wax, a natural wax, or the like is used. Examples of the polyolefin wax include polyethylene, polypropylene, polybutylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-
Pentene copolymer, ethylene-3-methyl-1-butene copolymer, or olefin and other monomers such as vinyl esters, haloolefins, (meth) acrylates, (meth) acrylic acid or Examples thereof include a copolymer with a derivative thereof and the like, and it is preferable that the weight average molecular weight is about 1,000 to 45,000. Also, as a natural wax, carnauba wax,
Examples include montan wax and natural paraffin. <Polymerized Toner> The polymerized toner of the present invention can be obtained by performing suspension polymerization in an aqueous solution containing a polymerizable monomer and a polymerization initiator. As the polymerizable monomer used in the production of the toner of the present invention, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,3 4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n- Styrene such as nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and derivatives thereof; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride, vinylidene chloride, vinyl bromide, fluorine Vinyl halides such as vinyl chloride; vinyl acetate, vinyl propionate, benzoic acid vinyl Vinyl esters such as methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, Α-methylene aliphatic monocarboxylic esters such as phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acryl Acrylates such as n-octyl acid, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether Vinyl ethers such as ter, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-
N-vinyl compounds such as vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; and vinyl monomers such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

Examples of the polymerization initiator used for the polymerization of the above monomers include benzoyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, potassium persulfate, ammonium persulfate, Acetyl peroxide,
Tetramethylthiuram disulfide, azobisisobutyronitrile, azobiscyclohexanenitrile, phenylazotriphenylmethane, triethylaluminum,
Trimethylaluminum, ethylaluminum dichloride, diethylaluminum chloride, tetraethyllead, diethylzinc, diethylcadmium, tetraethyltin, titanium tetrachloride, aluminum chloride, aluminum bromide, stannic chloride, boron trifluoride diethyl etherate, trifluoride Examples thereof include boron chloride, zinc chloride, and phosphorus pentafluoride, which can be used to polymerize a monomer. Generally about 0.5 to 5 parts by weight of monomer
% Initiator is sufficient.

In the present invention, a surfactant can be used for accelerating the dispersion of the monomer composition during dispersion and polymerization. Examples of such a surfactant include sodium dodecylbenzenesulfonate and tetradecyl. Sodium sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium allyl-alkyl-polyethersulfonate, sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium stearate, 3 , 3-Disulfonediphenylurea-
4,4-diazo-bis-amino-8-naphthol-6
Sodium sulfonate, ortho-carboxybenzene-
Azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-
And naphthol-sodium disulfonate.

The flash fixing toner of the present invention further comprises an infrared absorbing material. The infrared absorbing material used in the present invention preferably has a maximum absorption wavelength of 750 to 1100 nm, more preferably 800 to 1100 nm. 800-110
An infrared absorbing dye having an absorption peak at 0 nm and having substantially no absorption in the visible region is preferable.

The fact that there is substantially no absorption in the visible region means that 6
The value of the absorbance of the infrared-absorbing dye at 50 nm is 15% or less of the one having the maximum absorbance among the absorption peaks of the infrared-absorbing dye in the range of 750 to 1100 nm. When in this range, it can be visually considered that the color has substantially no color.

In the flash fixing toner of the present invention, the infrared absorbing dye is used by dissolving or dispersing it in a binder resin or adsorbing it on the surface of the toner resin.

Specific examples of the infrared absorbing agent used in the present invention include, for example, cyanine compound, diimonium compound, aminium compound, metal complex compound, phthalocyanine compound, anthraquinone compound, pyrylium and naphthalocyanine. Compounds and the like can be used.

The flash fixing differs from the heat roll fixing in that the xenon flash lamp irradiates light (mainly near-infrared light having a wavelength of 800 nm to 1100 nm) and generates heat. The temperature reaches about 600 ° C. Therefore, when the thermal decomposition start temperature of the infrared absorbent, that is, the heat-resistant temperature is low, the decomposition gas may cause voids (white spots) in the fixed image. Therefore, the heat-resistant temperature of the infrared absorbent is preferably 230 ° C. or higher, more preferably 250 ° C. or higher, and most preferably 300 ° C. or higher.

In the flash fixing toner of the present invention,
The amount of such an infrared absorber added is in the range of 0.01% by mass to 1% by mass of the whole toner composition. That is, if the amount added is less than 0.01% by mass, even if the infrared absorbent is dissolved in the binder resin and dispersed at the molecular level, there is a high possibility that it will be difficult to obtain sufficient fixability, while If the amount exceeds 1% by mass, there is no problem in terms of fixability, but it is not only economically disadvantageous but also has a possibility of adversely affecting the color tone, chargeability and the like of the toner. That's why.

[0035]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

<< Preparation of Toner >> The toner of the present invention was prepared as follows.

<Pulverized Toner> 100 parts of polyester resin 8 parts of pigment (yellow) 8 parts of pigment (magenta) 3 parts of pigment (cyan) 4 parts of pigment (black) 10 parts Infrared absorbing dye (pyridium, λmax = 820 nm, the _{abs 650 / abs 8 20 = 0.01} ) 0.5 part of polypropylene 3 parts (polyester resin) neopentyl glycol 132g ethylene glycol 60g terephthalic acid 279g dibutyltin laurate 1.5g above ingredients, a thermometer, stainless steel Stir bar,
The mixture was charged into a 2-liter glass four-necked flask equipped with a glass nitrogen inlet tube and a falling condenser, and was heated in a nitrogen atmosphere at room temperature under a nitrogen atmosphere in a mantle heater.
After 5 hours of reaction with stirring at 0 ° C., the reaction was further continued at 210 ° C., and when no change was observed in the value of the softening point measured according to ASTME28-51T, 1,2,4
-Add 108 g of benzenetricarboxylic anhydride, continue the reaction at 210 ° C., follow the progress of the reaction by the above softening point, when the softening point reaches 140 ° C., stop the reaction and cool to room temperature Then, a polyester was obtained. (A polyester resin having a softening point of 140 ° C. was obtained.) (Pigment) Yellow color: Lionol Yellow No. 1 1206 (manufactured by Toyo Ink Co., Ltd.) Magenta color: Lionel Red CP-A (manufactured by Toyo Ink Co., Ltd.) Cyan color: phthalocyanine blue (Lionol Blue E)
S) (manufactured by Toyo Ink Co., Ltd.) Black color: Black Pearls L (Cabot Corporation)
Made)

[0038]

Embedded image

Abs ₆₅₀ / abs ₈₂₀ represents the ratio of the absorbance at 650 nm to the absorbance at 820 nm.

The above toner composition was sufficiently mixed with a powder mixer (High Speed Mixer, manufactured by Fukae Kogyo Co., Ltd.), and then melt-kneaded with Labo Plast Mill (manufactured by Toyo Seiki Co., Ltd.). After cooling, the kneaded material was coarsely pulverized and further finely pulverized by a jet mill. The obtained finely pulverized product was classified by an air classifier to obtain a colored powder having an average particle diameter of 8 to 9 μm. The particle size is measured by a laser diffraction particle size distribution analyzer SALD-1100.
The volume average particle diameter was measured using (manufactured by Shimadzu Corporation).

To 100 parts by mass of this colored powder, 0.4% of hydrophobic silica R972 (manufactured by Nippon Aerosil Co., Ltd.) was added and uniformly mixed with a Henschel mixer to obtain a toner.

<Polymerized Toner> (Monomer Composition) Styrene 90 parts Butyl methacrylate 10 parts Pigment (yellow) 8 parts Pigment (magenta) 3 parts Pigment (cyan) 4 parts Pigment (black) 10 parts Infrared absorbing dye (SIR130, metal complex type, λmax = 920 nm, abs _{65 0} / abs ₉₂₀ = 0.1, manufactured by Mitsui Chemicals, Inc.) 0.5 part of the same pigment as the pigment used in the pulverized toner 0.5 part Slip agent (polypropylene) 5 parts) The above monomer composition was sufficiently mixed and homogenized by a sand grinder, and 1.8 parts of 2,2'-azobis (2,4-dimethylvaleronitrile) was further added as a polymerization initiator. By the way, abs ₆₅₀ / abs ₉₂₀ is, 920
The ratio of the absorbance at 650 nm to the absorbance at nm is shown.

(Aqueous Medium) (A) Trisodium phosphate dodecahydrate 25.6 parts (Na ₃ PO ₄ .12H ₂ O) Sodium dodecylbenzenesulfonate 0.04 parts (C ₁₂ H ₂₅ C ₆ H ₄₎ SO ₃ Na) Water (H ₂ O) 53.4 parts (B) Calcium chloride (CaCl ₂ ) 11.2 parts Water (H ₂ O) 102.0 parts The above (A) and (B) were mixed, and Water-soluble inorganic compound [C
a ₃ (PO ₄ ) ₂ ] was prepared. The poorly water-soluble inorganic compound [Ca ₃ (PO ₄ ) ₂ ] is produced by a reaction represented by the following formula.

Formula 2Na ₃ PO ₄ + 3CaCl ₂ → Ca ₃ (PO ₄ ) ₂
+ 6NaCl [Preparation of suspension] The above monomer composition was charged into the above aqueous medium and suspended using a homomixer (manufactured by Tokushu Kika Co., Ltd.) to prepare a fine particle suspension.

[Preparation of Associated Particles] The polymerization was started at 70 ° C. in a nitrogen atmosphere while stirring the suspension at a low speed. When the degree of polymerization of the polymerized particles reaches 40, hydrochloric acid (H
Cl) was added to adjust the pH in the system to 2, and the polymerization was continued. The system during the polymerization was analyzed by ESCA (surface analysis) using a device (model PHI560) manufactured by Perkin Elmer Co., Ltd., and the poorly water-soluble inorganic compound [C
a ₃ (PO ₄ ) ₂ ] was decomposed by addition of hydrochloric acid (HCl) as shown by the following formula, and it was confirmed that almost all were removed (dissolved). In addition, since the reaction of the following formula occurs under the condition that the pH of the suspension is less than 5, the pH of the suspension is 5
Hydrochloric acid (HCl) may be added so as to be less than.

The formula Ca (PO ₄ ) ₂ + 6H ⁺ → 3Ca ²⁺ + 2H ₃ P
Five hours after the start of O ₄ polymerization, the molecular weight of the polymer particles was saturated, so the polymerization was terminated, and polymer particles were obtained. The degree of polymerization is determined by the following equation: degree of polymerization = molecular weight of polymer particles at a certain point of time / saturated molecular weight of polymer particles × 100. At the end of the polymerization), polymer particles were sampled at each point in the reaction, and the molecular weight was measured and calculated. The molecular weight was measured by GPC (gel permeation chromatography).

[Post-treatment] The polymer particles were put into an aqueous hydrochloric acid solution (pH = 1) to completely dissolve and remove the slightly remaining poorly water-soluble inorganic compound [Ca ₃ (PO ₄ ) ₂ ]. After washing with water, filtration and drying, a suspension polymerization toner was obtained. The average particle size was 5.8 μm. The volume average particle diameter of the toner was measured using a laser diffraction particle size distribution analyzer SALD-1100 (manufactured by Shimadzu Corporation).

<< Heat Shrink Label >> A developer comprising 4 parts of the toner thus obtained and 96 parts of a carrier prepared as described below was set in a Konica KL-2010 color printer (manufactured by Konica Corporation), and After forming an unfixed image on the heat-shrinkable film, flash fixing was performed using a xenon flash lamp. No deformation was observed in any of the heat-shrinkable films, and the fixed image was firmly fixed on the heat-shrinkable film.

<Carrier> 1000 parts of core material particles (spherical ferrite particles, average particle size 80 μm) and coating resin (methyl methacrylate-styrene copolymer particles, copolymer molar ratio 6: 4, Mw = 130,000) , Mw / Mn = 1.
9, 10.5 parts of a weight average particle diameter of primary particles of 0.1 μm, glass transition point Tg = 65 ° C.) and 4.5 parts of fluorinated carbon (fluorine content x = 1.0) were horizontally rotated. The mixture was charged into an airfoil mixer and mixed and stirred at 30 ° C. for 15 minutes under the condition that the peripheral speed of the horizontal rotary blade was 12.4 m / sec. Then, the mixture was heated to 78 ° C. and stirred for 30 minutes. A resin-coated carrier having a fluorinated carbon content of 30% by mass was obtained. The volume resistivity of this carrier is 1 × 10 ¹² Ω · cm
Met.

<Heat-shrinkable film> PS shrinkable film (GMAS, manufactured by Gunze Co., Ltd., 50 μm)
m) PET shrink film (Gunze Co., Ltd., TAS, 50μ)
m) The heat-shrinkable label thus prepared was put on the shoulder of the PET bottle, passed through a shrink tunnel having a first zone (hot air temperature 100 ° C.) and a second zone (hot air temperature 200 ° C.), and shrunk. Thereafter, evaluation was made on whether or not there was distortion or wrinkles in the printing of the label. As a result, there was no distortion or wrinkles, and labeling of a beautiful finish was performed.

[0051]

According to the present invention, a method for printing a heat-shrinkable label which can be formed on-demand with high quality, toughness and excellent label mounting suitability without denaturing the heat-shrinkable film is obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // G09F 3/04 G03G 9/08 384

Claims (5)

[Claims] 1. A method for printing a heat-shrinkable label, comprising forming an image on a heat-shrinkable film using an electrophotographic toner for flash fixing. 2. The method for printing a heat-shrinkable label according to claim 1, wherein the electrophotographic toner for flash fixing contains a polymerized toner. 3. The method for printing a heat shrinkable label according to claim 1, wherein the electrophotographic toner for flash fixing contains a slipping agent. 4. The method for printing a heat-shrinkable label according to claim 1, wherein the flash fixing electrophotographic toner contains an infrared absorbing material. 5. The heat shrinkage according to claim 4, wherein the infrared absorbing material is an infrared absorbing dye having an absorption peak at 800 to 1100 nm and having substantially no absorption in a visible part. Label printing method.