JP2002249165A - Plastic packing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economically provide a plastic packing material excellent in adhesive properties to a plastic film, drying characteristics of water-color ink and water resistance of printing without forming the previous primary layer and even for comparatively thin water-color in receptor layer. SOLUTION: This packing material is characterized in that a substrate ink layer formed with ink containing titanium oxide pigment of 15 to 50 wt.%, resin binder of 5 to 50 wt.% and a solvent as a residual to whole 100 wt.% on an at least a part of the plastic film, and after that, a water-color ink receptor of hydrofilic polymer is provided on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic packaging material, and more particularly to a water-based ink, particularly a plastic packaging material which can be printed by an ink jet method.

[0002]

2. Description of the Related Art Conventionally, various plastic packaging materials have been used for various article packaging materials for many reasons such as transparency of contents, excellent strength, excellent water resistance, and low cost because of their transparency. Widely used as. These plastic packaging materials are printed on at least a part of their surfaces for decoration and information transmission. Since the plastic film is hydrophobic, the above printing on the plastic film is usually performed on the underlayer by forming a base layer (concealing layer) using oil-based white gravure ink.

[0003] When the number of printed sheets is very large, normal gravure printing is suitable for printing on the underlayer.
If the number of prints is small, gravure printing increases costs. Especially for the printing of various small-quantity products, such as personal address names such as direct mail, names of medicine bags, usage methods, product lot numbers and bar codes of printed materials, etc. There is no other way but by sticking a sticker or the like on which predetermined items are separately printed. As a method for solving such a problem, printing of the above-mentioned address name, bar code, and other small lots by an ink jet method, which is a simple printing method, has been considered. However, since the plastic film is hydrophobic and the ink in the ink jet system is usually an aqueous ink, printing is possible, but the fixing of the ink is poor and the printing is easily disturbed by water droplets or the like. In addition, since the plastic film is non-water-absorbing, the printing of the aqueous ink is slow and continuous printing results in show-through, which is not practical.

In order to solve the above problems, a water-based ink receiving layer made of a hydrophilic resin is provided for the purpose of absorbing and retaining the water-based ink on the surface of the plastic film and imparting water resistance, abrasion resistance, drying property and the like to the print. Various proposals have been made. However, since the material forming the water-based ink receiving layer is mainly composed of a hydrophilic resin, the water-based ink receiving layer itself has poor adhesion to a plastic film and adheres to water droplets even when printed with the water-based ink. There is a problem of peeling. In addition, the medium of the water-based ink contains water as a main component and contains a relatively high-boiling water-soluble organic solvent, so that unlike the case of printing on paper, the plastic film does not absorb the medium. Therefore, the drying property of the ink is inferior. For example, in the case of address printing of envelopes, there is a problem that printed envelopes cannot be continuously overlapped, and the printing speed is significantly reduced.

[0005]

Although the problem of the adhesion of the aqueous ink receiving layer can be improved to some extent by forming a primer layer on a plastic film in advance, it is not sufficient at present. Also, general plastic packaging materials are very inexpensive, so there is a cost problem. On the other hand, the problem of water resistance of printed images is
The problem is solved by using the water-based pigment ink as the water-based ink. However, since the pigment particles in the water-based pigment ink have no affinity for the plastic packaging material or the water-based ink receiving layer by itself, the formed printed image may have friction or the like. It easily peels off, causing problems such as background soiling and contamination of other articles. In particular, when a bar code or a zip code used together with the address of an envelope is formed, there is a problem that errors occur frequently in optical reading of the bar code or the like due to dirt or the like.

Accordingly, an object of the present invention is to provide an ink-receiving layer which does not have a conventional primer layer and which is relatively thin, and which has a good adhesion to a plastic film, a good drying property of a water-based pigment ink and a good print quality. An object of the present invention is to economically provide a plastic packaging material having excellent friction resistance and the like.

[0007]

The above object is achieved by the present invention described below. That is, in the first invention, a titanium oxide pigment 15
A base ink layer formed of an ink comprising a solvent in an amount of 50 to 50% by weight, a resin binder of 5 to 50% by weight and a total of 100% by weight, and a water-based ink receiving layer of a hydrophilic polymer provided on the surface thereof. The present invention provides a plastic packaging material characterized by the following.

[0008] The second invention provides a base ink layer comprising at least a part of a plastic film and an ink comprising 15 to 50% by weight of a titanium oxide pigment, 5 to 50% by weight of a resin binder and 100% by weight of a solvent in total. And an aqueous ink receiving layer made of a hydrophilic polymer is provided on the surface thereof, and further colored between the plastic film and the underlying ink layer and / or between the underlying ink layer and the aqueous ink receiving layer. Or, a plastic packaging material provided with a colorless ink layer is provided.

According to a third aspect of the present invention, at least a part of the plastic film contains 0 to less than 15% by weight of a titanium oxide pigment, 1 to 40% by weight of a colored pigment, and 5 to 50% by weight of a resin binder.
And an opaque or translucent colored base ink layer formed of an ink comprising a solvent in an amount of 100% by weight in total, and a water-based ink receiving layer made of a hydrophilic polymer provided on the surface of the plastic. Provide packaging materials.

According to the first invention, a base ink layer is formed on a required portion of a plastic film by using a white ink for surface printing or a white ink for an envelope, which has been used for the conventional base printing of a plastic film. By providing an aqueous ink receiving layer made of a hydrophilic polymer,
A plastic package that does not form a primer layer as in the past and is excellent in adhesion of the aqueous ink receiving layer, drying properties of the aqueous pigment ink, and abrasion resistance of printing, even if the aqueous ink receiving layer is relatively thin. The material can be provided economically.

[0011] According to the second invention, in addition to the first invention, between the plastic film and the underlying ink layer,
And / or by providing a colored or colorless ink layer between the base ink layer and the aqueous ink receiving layer, even if the printed surface is colored to a desired hue, the adhesion of the aqueous ink receiving layer and the aqueous pigment ink It is possible to economically provide a plastic packaging material which is excellent in drying properties and friction resistance of printing, and is also excellent in design and aesthetic appearance.

According to the third invention, a base ink layer is formed on a required portion of the plastic film with a colored gravure printing ink used for printing a conventional plastic film, and an aqueous ink comprising a hydrophilic polymer is formed on the surface thereof. By providing the receiving layer, the primer layer is not formed as in the related art, and even if the aqueous ink receiving layer is relatively thin, the adhesion of the aqueous ink receiving layer, the drying property of the aqueous pigment ink, and the rub resistance of the print are obtained. It is possible to economically provide a plastic packaging material having excellent properties.

[0013]

Next, the present invention will be described in more detail with reference to preferred embodiments. First invention As the plastic film used in the present invention, for example, a biodegradation of a polyethylene film, a polypropylene film, a polyvinylidene chloride film, a polyester film, a polyamide film having a thickness of 9 to 120 μm; a polylactic acid film, a polybutylene succinate and the like Resin film; other plastic films, laminates of these films, or laminates of these films with aluminum foil, paper, non-woven fabric, laminates of aluminum, alumina, silica, and other vapor-deposited films;
Any material conventionally used as a plastic film can be used in the present invention.

In the present invention, a necessary portion of the plastic film, for example, in the case of a plastic envelope,
The base ink layer is formed only on the part where information is printed, such as the display of the contents, its description, decoration, address name, zip code, bar code, etc., and the other parts are transparent so that the contents can be seen It is preferred that The printing ink used to form the base ink layer is the white ink for surface printing or the white ink for envelopes used for printing conventional plastic films, and these base ink layers provide clear information to be printed thereon. Is a base ink layer having a high concealing property, and is usually white, but is not limited to white and may be colored in another color as long as a printed image can be read.

In the present invention, the preferred ink composition is titanium oxide pigment 15 to 50% when the whole is 100% by weight.
% By weight and a resin binder in an amount of from 5 to 50% by weight, with the balance being a solvent, and as necessary, other components such as wax, a crosslinking agent such as a titanium chelating agent, water-absorbing resin particles, soy protein powder, It may include chromatic pigments and the like. As a solvent for dissolving and dispersing the above components, for example, toluene, xylene, methyl ethyl ketone (ME
Conventional gravure ink solvents such as K), methyl isobutyl ketone, methanol, ethanol, isopropyl alcohol (IPA), ethyl acetate (ethyl acetate), butyl acetate, and methoxypropanol are used.

When the amount of titanium oxide is less than 15% by weight, the concealing property of the underlying ink layer is poor unless the underlying ink layer is made thick. On the other hand, when the amount of titanium oxide exceeds 50% by weight, it becomes difficult to apply a thin and uniform ink. Preferably it is 25 to 35% by weight. Further, the extender pigment may not be used as a component of the ink, but when used, it is used in an amount of up to 30% by weight, preferably 5 to 25% by weight in the ink.
By using the pigment, the dryness of the aqueous pigment ink after the formation of the aqueous ink receiving layer is improved, and the apparent dryness can be achieved in a short time. Preferred extender pigments include, for example, the above-mentioned porous extender pigments such as silica, calcium carbonate, magnesium carbonate, and basic magnesium carbonate. If it exceeds 30% by weight, the total amount of the white pigment and the extender pigment in the ink will increase, making it difficult to form a uniform and thin base ink layer.

As the resin binder, for example, a usual resin binder for gravure ink such as polyamide, chlorinated polypropylene, polyurethane, polyester, acrylic resin, vinyl chloride resin, cellulose resin such as nitrocellulose, and maleic acid resin is used. You. These resin binders are mixed and used so as to maximize the adhesion according to the type of the plastic film to be applied. The amount of the resin binder used is 5 to 50% by weight, preferably 15 to 30% by weight. Such white ink for front printing and white ink for envelopes are, for example, Ultima 791 white, Bright Top Mail I709 White M (Dai Nippon Ink and Chemicals), OPP Mail 63 White, PAN
N color S631 white (manufactured by Toyo Ink), P-21
DM White (OS), HR Color 701 White (LX), Hyramic SCR White (Daiichi Seika Kogyo), NEW REX
582 white, LAP DM3 white (combined inks) and the like, and are available from the market as they are or by adding or adding porous extender pigment, wax such as polyethylene wax, water-absorbent resin particles, soy protein powder, etc. It can be used in the present invention.

Particularly, as the water-absorbing resin particles, a conventionally known water-absorbing resin may have a particle size of 0.5 to 15 μm, preferably 1 to 1 μm.
Those adjusted to 0 μm are useful. If the particle size exceeds 15 μm, problems arise in printability when printing white ink, which is not preferable. On the other hand, it is difficult to produce water-absorbent resin particles having a particle size of less than 0.5 μm. The used amount of the water-absorbing resin particles is an amount occupying 0 to 30% by weight, preferably 1 to 15% by weight in the ink composition. By including these water-absorbing resin particles in the base ink layer, the drying speed of the aqueous pigment ink for ink jet applied to the ink receiving layer is improved. When soy protein powder is used, a powder having a particle size of 0.5 to 30 μm is available. Even if it is contained in the white ink, it does not cause a problem in printability at the time of printing. The water absorption performance of the layer can be more uniformly improved. The particle size of the soy protein is more preferably 1.0 to 10 μm, and the amount of the soy protein powder used is from 0 to 0 in the ink composition.
The amount occupies 30% by weight, preferably 1 to 15% by weight.

The printing of the plastic film with the above-mentioned ink may be performed on the entire surface. However, in general, only the necessary area of the plastic film is coated, for example, in the case of an envelope, only in the content display area or the address entry column. . Printing is performed by normal gravure printing, the thickness is about 0.5 ~
12 g / m ² is preferred. If the coating thickness is too thin, the concealing properties will be insufficient, the image of the finally applied aqueous pigment ink will be disturbed, and the apparent drying time will be long. On the other hand, if the coating thickness is too large, the concealing property and the drying property of the aqueous pigment ink are improved, but disadvantageously in cost. Preferably it is 1.5-6 g / m < ² >. In order to make the base ink layer thicker, printing may be performed a plurality of times.

In the present invention, an aqueous ink receiving layer is formed on the surface of the base ink layer formed as described above. The aqueous ink receiving layer is formed from a coating solution containing a hydrophilic polymer. As the hydrophilic resin, for example, polyvinyl alcohol, partially saponified polyvinyl alcohol, polyethylene glycol, polyethylene glycol-polypropylene glycol block copolymer, polyurethane resin having a polyethylene glycol segment, polyester having a polyethylene glycol segment, polyvinyl pyrrolidone, acrylic polyol resin, Examples thereof include poly (meth) acrylamide and the like, and a mixture thereof, and a hydrophilic ultraviolet curable resin. In addition, any known hydrophilic resin useful for forming the aqueous ink receiving layer can be used. In order to improve the adhesion of the aqueous ink-receiving layer to the base, for example, a titanium coupling agent, an isocyanate-based curing agent, a chlorinated polypropylene (for example, Supercron 813A, Nippon Paper) ) May be added.

When the pigment in the aqueous pigment ink used for printing the plastic packaging material of the present invention has been anion-treated, a basic substance may be used in combination with the hydrophilic polymer. Examples of these basic substances include polyallylamine, polyamine sulfone, copolymers thereof, polyvinylamine, and the like, and mixtures thereof. Many other fixing agents for such anion-treated pigments are known, and any of these known fixing agents can be used in the present invention. Particularly preferably, a spherical cationic polymer is used in combination with the fixing agent. The spherical cationic polymer is obtained by treating the above polyallylamine, polyamine sulfone, a copolymer thereof, polyvinylamine and the like with a treatment such as cross-linking, while being hydrophilic, but hardly water-soluble, and powder, As an aqueous dispersion or an organic solvent dispersion, for example, it is available from Arakawa Chemical Co., Ltd. under a trade name such as “Lunaper QA series” and can be used in the present invention. These organic basic substances are used in an amount of 0 to 50 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the coating solution. If the amount of the basic substance is too small, the fixability of the anion-treated pigment in the ink will be insufficient, and the rub resistance will decrease. These fixing agents are preferably soluble or finely dispersible in an organic solvent. Note that an organic acid such as maleic acid, fumaric acid, ferulic acid, succinic acid, oxalic acid, tartaric acid, or the like can be added to the aqueous ink receiving layer. In particular, when ferulic acid, succinic acid, and tartaric acid are added to the ink receiving layer, the apparent drying speed of the anion-treated pigment ink applied to the ink receiving layer is improved. This is thought to be due to the fact that the pigment cationically treated with these acids is neutralized at the moment of contact with the ink receiving layer.

Examples of the hydrophilic polymer having a basic group (cation group) include cation-modified polyvinylpyrrolidone, cation-modified polyvinyl alcohol, cation-modified polyurethane resin, cation-modified acrylic resin, cation-modified poly (meth) acrylamide, and the like. And mixtures thereof. These cationic polymers can be used alone or in combination with the above-mentioned organic basic substances. These polymers are preferably soluble or finely dispersible in organic solvents. In the present invention, "basic" or "cationic" means having a primary, secondary or tertiary amino group.

The water-based ink-receiving layer is made of a hydrophilic polymer which may contain the above-mentioned basic organic substance and / or a polymer having a basic group by a suitable organic solvent such as methanol, ethanol, IPA, MEK, methyl isobutyl ketone, or the like. Solids in ethyl acetate, butyl acetate, methoxypropanol, toluene, xylene or mixtures thereof
It is dissolved or finely dispersed to about 30% by weight to obtain a coating liquid.
At this time, dimethylformamide, formamide, dimethylsulfoxide and the like may be used in combination as a part of the solvent. In this coating liquid, a crosslinking agent, a porous extender, the water-absorbent resin powder, soy protein powder, waxes such as spherical polyethylene wax, an anti-settling agent, the organic acid, a silicon-based surfactant, Other optional additives can be included. In particular, the same water-absorbent resin particles as above are used in an amount of 0 to 50% by weight of solids, preferably 1 to 15% by weight.
The spherical polyethylene wax having a particle size of 0.5 to 10 μm is added in an amount of 0 to 10% by weight, preferably 1 to 5% by weight. In order to increase the coating thickness of the ink receiving layer, the coating may be performed a plurality of times. Further, the ink receiving layer may be colored in an arbitrary hue as long as the reading of characters printed on the surface is not hindered.

The above coating liquid is applied to the surface of the base ink layer by a gravure method or another method in a solid content of about 0.1%.
The aqueous ink receiving layer is formed by coating and drying at a coating amount of 5 to 12 g / m ² , preferably 2 to 6 g / m ² , and the plastic packaging material of the present invention is obtained. When the coating amount is less than the above range, the retention of the applied aqueous pigment ink is insufficient, the dots are spread, and the image is disturbed. Further, when the coating amount exceeds the above range, the drying property of the applied ink is improved, but a higher drying property is not practically required.

The water-based ink receiving layer formed as described above unexpectedly has extremely excellent adhesion to the hydrophobic plastic film via the base ink layer, and the test piece is kept at room temperature for 6 hours. After immersion in water, it did not peel off even when rubbed multiple times with a cotton swab. On the other hand, in the case of the test piece in which the water-based ink receiving layer was formed directly on the plastic film instead of the base ink layer, the water-based ink receiving layer was easily formed by rubbing several times with a cotton swab after about 2 hours during the test. Has peeled off. The excellent adhesion of the aqueous ink receiving layer is such that the surface of the base ink layer has fine irregularities due to a large amount of white pigment or extender pigment, and as a result, the adhesion area with the aqueous ink receiving layer is reduced. One reason is considered to be very large, but the adhesion was so excellent that it could not be understood only by this reason.

Second invention In the second invention, in addition to the first invention, a colored or colorless ink layer is provided between the plastic film and the base ink layer in order to further improve the design and appearance of the packaging material. Provide. This is useful when providing a colored ink layer or a colorless ink layer (for example, a matte ink layer, a glossy ink layer, etc.) in addition to the printed portion of the plastic film.
When printing with silver ink, yellow ink, matte ink, glossy ink, and other hue inks, the same excellent properties as described above can be obtained by providing the base ink layer and the aqueous ink receiving layer on the surface of these ink layers. The effect is obtained.
In particular, gold ink and silver ink have very high concealing properties. Therefore, when the packaging material of the present invention is used for an envelope or the like, the inside of these ink layers can be concealed sufficiently. In addition, the above-mentioned colored ink layer or colorless ink layer may be provided only in the printing portion (that is, in the same region as the base ink layer), or provided in an area slightly larger than the base ink layer as shown in FIG. In addition, a colored or colorless bordering ink layer can be provided around the base ink layer.

Further, a similar colored or colorless ink layer can be formed between the base ink layer and the aqueous ink receiving layer. This case is also useful when providing a colored ink layer or a colorless ink layer (for example, a matte ink layer, a glossy ink layer, etc.) in addition to the printed portion of the plastic film. The same excellent effect as described above can be obtained by printing the entire surface of the film with gold ink, silver ink, yellow ink, matte ink, glossy ink, or other hue ink, and providing the aqueous ink receiving layer thereon. Is obtained. The colored ink layer or the colorless ink layer may be provided only in the printing portion (that is, in the same region as the base ink layer), or provided in an area slightly larger than the base ink layer as shown in FIG. In addition, a colored or colorless bordering ink layer can be provided around the base ink layer. Further, as shown in FIG. 3, a colored or colorless ink layer may be provided in a smaller area than the underlying ink layer. Further, the colored ink layer or the colorless ink layer may be provided between the plastic film and the base ink layer and between the base ink layer and the aqueous ink receiving layer.

As the colored or colorless printing ink used in the above embodiments, gravure printing ink or a medium thereof, which has been widely used for printing plastics, can be used. In particular, gold ink, silver ink, yellow ink, and matte / luster inks are preferable from the viewpoint of not lowering the contrast of printing and giving a high-quality feeling to printed matter. Examples of gold ink, silver ink, yellow ink, other colored inks, media, and the like include, for example, trade names PP-REX (gold, silver, 536 yellow) and their media, LAP (gold, Silver, 536
Yellow) and their media, the CLIOS series (inks of each color) manufactured by The Inktech, and their media can be obtained from the market and used in the present invention.

Third invention In the third invention, the same plastic film as in the first invention is required, for example, in the case of a plastic envelope,
The base ink layer is formed only on the part where information is printed, such as the display of the contents, its description, decoration, address, name, zip code, bar code, etc.The other parts are transparent so that the contents can be seen Preferably, it is in a state. The printing ink used for forming the base ink layer is a colored gravure printing ink used for printing a conventional plastic film, and these base ink layers are light-colored or colored so that the information printed thereon becomes clear. It is a bright base ink layer, and its hue is not particularly limited, but is colored in a light color other than gold, silver, yellow, or black in consideration of design and aesthetic appearance.

The composition of the base ink suitable in the present invention is such that the titanium oxide pigment is
-15% by weight, a coloring pigment of 1-40% by weight and a resin binder of 5-50% by weight, the remainder being a solvent, and a wax as other components, if necessary.
It may contain a crosslinking agent such as a titanium chelating agent, water-absorbing resin particles, and the like. As a solvent for dissolving and dispersing the above components,
For example, toluene, xylene, MEK, methyl isobutyl ketone, methanol, ethanol, IPA, ethyl acetate,
Conventional gravure ink solvents such as butyl acetate and methoxypropanol are used.

In the present invention, when a gold ink or a silver ink is used as the base ink, since these inks are very excellent in hiding properties, it is not necessary to use titanium oxide. When using a coloring ink other than the gold ink or the silver ink as the base ink, the titanium oxide may not be used, but when used, it is preferably used at 3 to less than 15% by weight. In this case, if the amount of titanium oxide is small, even if a large amount of colored pigments other than gold and silver are used, the concealability of the underlying ink layer will be poor unless the underlying ink layer is made thick. On the other hand, when titanium oxide is not used, it is preferable to use another white pigment or extender instead of titanium oxide. When the amount of the color pigment is small, the concealing property of the ink layer is poor. On the other hand, when the amount of the color pigment is too large, it becomes difficult to apply a thin and uniform ink. Preferably it is 15 to 35% by weight. The extender may not be used as a component of the ink, but when used, it is used in an amount of 3 to 30% by weight in the ink. By doing so, although the reason is not clear, the dryness of the aqueous pigment ink after forming the aqueous ink receiving layer to the touch is improved, and it is apparently dried in a short time.

The resin binder is the same as in the first invention. As the above-mentioned colored printing ink, a gravure printing ink that has been widely used for printing plastics can be used. In particular, gold ink, silver ink, yellow ink, and colored matte / luster ink are preferable from the viewpoint of not lowering the contrast of printing and giving the printed matter a sense of quality. In particular, gold ink and silver ink are particularly preferable because of high concealing property. The gold ink, silver ink, yellow ink, and other colored inks are the same as in the second invention.

Further, a printing ink having a titanium oxide content of less than 15% by weight by adding the above-mentioned coloring ink to the conventionally known white printing ink and envelope white ink and mixing the resulting ink with each other is used. You may. Such white ink for front printing and white ink for envelopes are the same as those in the first invention. The same applies to the water absorbing resin particles as in the first invention. The printing of the plastic film with the above ink, the aqueous ink receiving layer, the basic substance, and the like are the same as in the first invention.

When printing was carried out with the aqueous pigment ink on the plastic packaging material obtained in the first to third inventions as described above, the rub resistance of the printed matter was unexpectedly excellent. That is, when printing is performed on an ordinary plastic film with an aqueous pigment ink, it is natural that the drying property is slow, but the rub resistance of the printed matter after drying is very poor. That is, since the printed matter is formed simply by the pigment adhering to the surface of the plastic film, for example, if the finger is rubbed, the pigment forming the printed matter is easily wiped off, which is not practical. On the other hand, when the plastic packaging material of the present invention is printed with an aqueous pigment ink, the rub resistance of the print is extremely excellent. The reason for this is unknown, but when the aqueous pigment ink is applied to the ink receiving layer, the aqueous medium of the ink swells the ink receiving layer in the form of dots, and the aqueous medium is absorbed by the ink receiving layer. Some or all of the pigment particles may be embedded in the swollen ink receiving layer by penetrating into micropores formed by silica or spherical particles, or the swollen hydrophilic resin of the ink receiving layer may be a pigment. It is assumed that it acts as a binder for the particles.

The plastic packaging material of the present invention obtained as described above is suitable as a packaging material for various articles such as various foods and medicines. , Individual various information is easily recorded. In particular, the plastic packaging material of the present invention is useful as a material for an envelope made of a plastic film. That is, the base ink layer and the water-based ink receiving layer are continuously formed at predetermined positions of a plastic film, and after cutting and sealing, an address and other individual information are continuously printed by an ink jet method. be able to. The aqueous pigment ink used for printing is
It contains water as at least a part of the liquid medium, contains a pigment as at least a part of the coloring material, and may further contain ordinary additives such as a water-soluble organic solvent and a dye. For example, an ink used in a general writing instrument may be used, but an aqueous pigment ink used by an ink jet method is useful. The ink jet device used and the water-based pigment ink used for the ink jet device may be commercially available products, and are not limited at all. In the present invention, the term "pigment" includes, in addition to pigments usually referred to as carbon black, a fluorescent dye having no sulfone group or carboxyl group, a fluorescent brightener, a disperse dye, an oil-soluble dye, and the like. It is.

[0036]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, “parts” or “%” is based on weight unless otherwise specified. [First invention] <Example 1> White linear gravure ink having the following composition was applied to a linear low-density polyethylene film having a thickness of 40 µm by a gravure printing machine at a coating amount of 2.5 g / m ² when dried and dried. To form a white base ink layer. A coating liquid for an aqueous ink receiving layer having the following composition is printed twice on a gravure printing machine on the surface of this layer, and a coating amount of 5.5 g / m ² when dried is applied. Apply and dry to form an aqueous ink receiving layer,
This was cut into a size of 15 × 15 cm to obtain a test piece a.

White ink composition: (LAP D manufactured by KYODO INK)
(Ink partially modified based on M-3 white)

Composition of coating solution:

Comparative Example 1 An aqueous ink receiving layer was applied directly to a film in the same manner as in Example 1 in the same manner as in Example 1 without providing a white base ink layer, and dried. Specimen b was cut to the size shown in FIG.

Example 2 A white gravure ink having the following composition was applied to a 16 μm-thick polyethylene terephthalate film with a gravure printing machine at a rate of 2.8 g / m ² when dried, and dried to form a white base ink layer. To form
A coating solution of an aqueous ink receiving layer having the following composition was applied to the surface of this layer by the same method as in Example 1 and dried, and this was cut into a size of 15 × 15 cm to obtain a test piece c.

White ink composition: (Dainichi Seika Kogyo P-21)
Ink partially modified based on DM white (OS)) ・ Titanium oxide 30 parts ・ Water absorbent resin powder (acrylic) 5 parts ・ Polyurethane resin 7 parts ・ Vinyl chloride resin 3 parts ・ Nitrocellulose resin 2 parts ・ Chlorine Polypropylene resin 1 part ・ Polyethylene wax 3 parts ・ Solvent (toluene / ethyl acetate / MEK) 49 parts

Composition of coating solution:

<Comparative Example 2> In Example 2, without providing a white base ink layer, an aqueous ink receiving layer was directly applied to a film by the same method as in Example 2 to the same thickness and dried. And cut into a test piece d.

Example 3 A white gravure ink having the following composition was applied to a 15 μm-thick nylon film with a gravure printing machine at a coating amount of 3.0 g / m ² when dried, and dried to form a white base ink layer. A coating solution of an aqueous ink receiving layer having the following composition was applied to the surface of this layer in the same manner as in Example 1 and dried, and this was cut into a size of 15 × 15 cm to obtain a test piece e.

White ink composition: (Ink partially modified based on Toyo Ink OPP Mail 63 White) ・ Titanium oxide 25 parts ・ Silica 15 parts ・ Polyurethane resin 20 parts ・ Polyethylene wax 3 parts ・ Solvent (toluene / vinegar ethyl acetate) / MEK) 37 copies

Composition of coating liquid: 35 parts of hydrophilic polyurethane resin (manufactured by Joint Ink) 6 parts of silica (Mizukasil P-78A) 6 parts of solvent (MEK / toluene / IPA) 59 parts

Comparative Example 3 An aqueous ink receiving layer was directly applied to a film in the same manner as in Example 3 with the same thickness as in Example 3 without providing the white base ink layer in Example 3, and dried. And cut into a test piece f. <Comparative Example 4> In Example 1, only the white base ink layer was provided and the aqueous ink receiving layer was not provided.
The test piece g was cut to a size of m.

<Evaluation Example> An ultra-high-speed general-purpose ink jet printer (DA-7000) manufactured by Tanac Co., Ltd. and its dedicated ink (Huered Packard Co., Ltd.) were applied to the test pieces a to g obtained in Examples and Comparative Examples. VERSATIL
A black image was formed using E BLACK C8842A, a water-based pigment ink: the pigment was carbon black), and the following tests were performed for each. Table 1 shows the results. 1. Drying property: After completion of printing, a white polyethylene film was wound around a finger, the film was pressed against a printing portion, and the time until ink did not adhere to the white film was measured. 2. Water-Resistant Adhesion of the Ink-Receiving Layer: The printed surface was rubbed with a cotton swab moistened with water, and the peeling state of the aqueous ink-receiving layer was observed. 3. Print abrasion resistance: The printed surface was rubbed with a finger after ink drying, and the tailing state of the printed image was observed.

[0049] In Table 1 above, the drying property is apparent drying, which is the time when the ink hardly adheres to the white film even when touched by a finger wound with the white film. No ink set-off occurs.

[Second Invention] <Example 1> A golden gravure ink having the following composition was applied to a linear low-density polyethylene film having a thickness of 40 µm by a gravure printing machine at a coating amount of 3.0 g / m ² when dried. 15cm
Applying and drying an area of × 15 cm to form a gold ink layer, and gravure printing of a white gravure ink having the following composition on an area of 14 cm × 14 cm on the surface of the gold ink layer, leaving an area of 1 cm width around the surface. A white base ink layer is formed by applying and drying at a coating amount of 2.5 g / m ² at the time of drying to form a white base ink layer, and a coating liquid for an aqueous ink receiving layer having the following composition is applied to a gravure printing machine on the surface of this layer. The printing was performed twice, coated and dried at a coating amount of 5.6 g / m ^{2 at} the rate of drying to form a water-based ink receiving layer, which was cut into the same size of 15 cm × 15 cm as the printing area. And

Gold Ink Composition: (LAP manufactured by Kyodo Ink)
Money)

White ink composition: (LAP D manufactured by KYODO INK CO., LTD.)
(Ink partially modified based on M-3 white)

Composition of coating solution:

<Comparative Example 1> In Example 1, only the water-based ink receiving layer was applied to the same thickness and dried in the same manner as in Example 1, and this was cut into a size of 15 × 15 cm to obtain a test piece b.

Example 2 A white gravure ink having the following composition was applied to a 16 μm-thick polyethylene terephthalate film by a gravure printing machine at an area of 14 cm × 14 cm at a rate of 2.8 g / m ² when dried and dried. A white gravure ink having the following composition was applied to the surface of this ink layer by a gravure printing machine at a rate of 3.1 g / m ^{2 at} a rate of 3.1 g / m ² , and then dried on a 15 cm × 15 cm area. Then, a silver ink layer was formed, and a water-based ink receiving layer coating solution having the following composition was applied to the surface of this layer in the same manner as in Example 1 so as to match the white ink layer, and dried. It was cut into a size of 15 × 15 cm to obtain a test piece c.

Silver ink composition: (LAP manufactured by Kyodo Ink)
Silver)

White ink composition: (Dainichi Seika Kogyo P-21)
Ink partially modified based on DM white (OS)) ・ Titanium oxide 30 parts ・ Water absorbent resin powder (acrylic) 5 parts ・ Polyurethane resin 7 parts ・ Vinyl chloride resin 3 parts ・ Nitrocellulose resin 2 parts ・ Chlorine Polypropylene resin 1 part ・ Polyethylene wax 3 parts ・ Solvent (toluene / ethyl acetate / MEK) 49 parts

Composition of coating solution:

<Comparative Example 2> Only the aqueous ink receiving layer in Example 2 was applied to the same thickness and dried in the same manner as in Example 2, and this was cut into a size of 15 × 15 cm to obtain a test piece d.

Example 3 A 15 cm thick nylon film was coated with a white gravure ink having the following composition by a gravure printing machine at a coating weight of 3.0 g / m ^{2 at} a rate of 15 cm × 1.
A 5 cm area was applied and dried to form a white base ink layer, and a yellow gravure ink having the following composition was dried on the surface of this ink layer with a gravure printing machine at a coating weight of 2.9 g / dry.
A 15 cm × 15 cm area was applied and dried at a ratio of m ² to form a yellow ink layer, and an aqueous ink receiving layer coating solution having the following composition was applied to the surface of this layer in the same manner as in Example 1 to the same thickness. After drying, this was cut into a size of 15 × 15 cm to obtain a test piece e.

Yellow ink composition: (LAP-
536 partially modified)

White ink composition: (Ink partially modified based on Toyo Ink OPP Mail 63 White) ・ Titanium oxide 25 parts ・ Silica 15 parts ・ Polyurethane resin 20 parts ・ Polyethylene wax 3 parts ・ Solvent (toluene / acetic acid ethyl acetate) / MEK) 37 copies

Composition of coating solution:

Comparative Example 3 In Example 3, only the aqueous ink receiving layer was applied to the same thickness and dried in the same manner as in Example 3, and this was cut into a size of 15 × 15 cm to obtain a test piece f. <Comparative Example 4> A test piece g was prepared by cutting only the gold ink layer and the white base ink layer in Example 1 but not providing the aqueous ink receiving layer to a size of 15 x 15 cm.

<Evaluation Examples> A black image was formed on the test pieces a to g obtained in Examples and Comparative Examples using the same printing system and water-based pigment ink as those of the first invention. The same test was performed.
Table 2 shows the results.

[0066] The drying properties are the same as in Table 1.

[Third Invention] <Example 1> A golden gravure ink having the following composition was applied to a linear low-density polyethylene film having a thickness of 40 μm by a gravure printing machine at a rate of 3.3 g / m ² when dried. A gold ink layer was formed by coating and drying, and a coating solution for an aqueous ink receiving layer having the following composition was printed twice on a surface of this layer with a gravure printing machine to give a coating amount of 5.6 g / m ² when dried. The aqueous ink receiving layer was formed by coating and drying at a predetermined ratio, and this was cut into the same size of 15 cm × 15 cm as the printing area to obtain a test piece a.

Golden ink composition: (PP-R manufactured by Kyodo Ink)
EX gold) ・ Disazo yellow 3 parts ・ Aluminum paste 10 parts ・ Nitrogenated cotton 8 parts ・ Polyamide resin 18 parts ・ Polyethylene wax 3 parts ・ Titanium chelate 3 parts ・ Solvent (toluene / ethyl acetate / IPA) 55 parts

Composition of coating solution:

Comparative Example 1 A water-based ink-receiving layer was applied directly on the surface of the film in Example 1 to the same thickness and in the same manner as in Example 1 without providing the gold ink layer, and dried.
This was cut into a size of 15 × 15 cm to obtain a test piece b.

Example 2 A silver gravure ink having the following composition was applied to a 16 μm-thick polyethylene terephthalate film by a gravure printing machine at a rate of 2.8 g / m ² when dried to form a silver ink layer. A water-based ink-receiving layer coating solution having the following composition was applied to the surface of this layer in the same manner as in Example 1 to the same thickness and dried.
It was cut into a size of 5 × 15 cm to obtain a test piece c.

Silver ink composition: (PP-R manufactured by Kyodo Ink)
EX silver) ・ 13 parts of aluminum paste ・ 8 parts of nitrified cotton ・ 18 parts of polyamide resin ・ 3 parts of polyethylene wax ・ 3 parts of titanium chelate ・ 55 parts of solvent (toluene / ethyl acetate / IPA)

Composition of coating solution:

Comparative Example 2 A water-based ink-receiving layer was applied directly to the film surface in the same manner as in Example 2 with the same thickness as in Example 2 without providing the silver ink layer in Example 2, and dried. And cut into a test piece d.

<Example 3> A yellow gravure ink having the following composition was applied to a 15 μm-thick nylon film by a gravure printing machine at a rate of 3.2 g / m ² when dried to form a yellow ink layer. Then, a coating solution of an aqueous ink receiving layer having the following composition was applied to the surface of this layer in the same manner as in Example 1 and dried, and this was cut into a size of 15 × 15 cm to obtain a test piece e.

Yellow ink composition: (PP-R manufactured by Kyodo Ink)
EX536)-Disazo Yellow 10 parts-Nitrified cotton 9 parts-Polyamide resin 22 parts-Polyethylene wax 4 parts-Solvent (toluene / ethyl acetate / IPA) 55 parts

Composition of coating liquid: 35 parts of hydrophilic polyurethane resin (manufactured by Joint ink) 6 parts of silica (Mizukasil P-78A) 59 parts of solvent (MEK / toluene / IPA)

<Comparative Example 3> In Example 3, an aqueous ink-receiving layer was applied to the same thickness as in Example 3 without providing a yellow ink layer, dried and cut into a size of 15 × 15 cm. Test piece f was used.

<Example 4> A test piece g was obtained in the same manner as in Example 3 except that the following green ink was used instead of the yellow ink in Example 3. Green ink composition: (PP-REX548 manufactured by Joint Ink) ・ 10 parts of phthalocyanine green ・ 5 parts of nitrified cotton ・ 16 parts of polyamide resin ・ 1 part of polyethylene wax ・ 68 parts of solvent (toluene / ethyl acetate / IPA) 68 parts <Comparative Example 4> In Example 1, only the gold ink layer was provided and the aqueous ink receiving layer was not provided.
Specimen h was cut to the size shown in FIG.

<Evaluation Example> A black image was formed on each of the test pieces a to h obtained in the examples and comparative examples using the same printing system and aqueous pigment ink as in the first invention. The same test was performed.
Table 3 shows the results.

[0081] The drying properties are the same as in Table 1.

Incidentally, an aqueous pigment ink (VERSATILE BLACK C8842) was used as an ink in a Baskuro HPQ inkjet system (manufactured by BUSKRO).
A, manufactured by HP Co., Ltd.), the address, name, and zip code were continuously printed at 600 × 200 dpi at a speed of 14,000 rPH. Even when the prints were overlaid, no ink set-off occurred.

[0083]

According to the first aspect of the present invention, a base ink layer is formed on a required portion of a plastic film by using a titanium oxide-containing white (which may be colored) ink used in the conventional printing of a plastic film base. However, by providing an aqueous ink receiving layer made of a hydrophilic polymer on the surface, no special primer layer is formed, and even if the aqueous ink receiving layer is relatively thin, the adhesion of the aqueous ink receiving layer and the aqueous It is possible to economically provide a plastic packaging material excellent in the drying property of the pigment ink, the rub resistance of printing, and the like.

According to the second invention, in addition to the first invention, a colored or colorless ink layer is provided between the plastic film and the base ink layer and / or between the base ink layer and the aqueous ink receiving layer. By doing so, no special primer layer is formed, and even with a relatively thin aqueous ink receiving layer, the aqueous ink receiving layer is excellent in adhesion, drying of the aqueous pigment ink, and abrasion resistance of printing, and the like. It is possible to economically provide a plastic packaging material excellent in design and aesthetic appearance.

According to the third invention, a base ink layer is formed on a required portion of a plastic film by using a colored gravure printing ink used for printing a conventional plastic film, and an aqueous ink comprising a hydrophilic polymer is formed on the surface thereof. By providing a receiving layer, a primer layer is not formed, and even if the aqueous ink receiving layer is relatively thin, the adhesion of the aqueous ink receiving layer, the drying property of the aqueous pigment ink, the rub resistance of printing, etc. It is possible to economically provide a plastic packaging material which is excellent in design and aesthetic appearance.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating one embodiment of the present invention.

FIG. 2 is a diagram illustrating another embodiment of the present invention.

FIG. 3 is a diagram illustrating another embodiment of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Miyamoto 45, Higashikujo Minamikawabe-cho, Minami-ku, Kyoto-shi, Kyoto (72) Inventor Ryohei Tsuboi 1-6-6, Tsuruhashi, Ikuno-ku, Osaka-shi, Osaka Joint-stock ink stock In-company (72) Inventor Kahiro Suzuki 1-7-8 Nishigahara, Kita-ku, Tokyo Bertex Komagome 4F Mansei Suzuki Co., Ltd. F-term (reference) 2C056 EA13 FB01 FC06 2H086 BA12 BA15 BA19 BA33 3E086 AB01 BA04 BA15 BA24 BB54 BB61 BB62 DA01 4F100 AA21B AJ02B AJ02C AJ11C AK01A AK01B AK01C AK04A AK07A AK16A AK41A AK46A BA03 BA04 BA05 BA07 BA10A BA10C CC00B CC00D CC00E DE01B DE01C DE04C GB15 JB05C JD14C JD15 JD15C JL10B JL10D JL10E JN01B JN01D JN01E JN02B YY00A YY00B YY00C

Claims (13)

[Claims] 1. A base ink layer is formed on at least a part of a plastic film with an ink comprising 15 to 50% by weight of a titanium oxide pigment, 5 to 50% by weight of a resin binder and 100% by weight of a solvent as a whole. And a water-based ink-receiving layer comprising a hydrophilic polymer on the surface thereof. 2. A base ink layer is formed on at least a part of a plastic film with an ink composed of 15 to 50% by weight of a titanium oxide pigment, 5 to 50% by weight of a resin binder and 100% by weight of a solvent in total. A water-based ink receiving layer made of a hydrophilic polymer is provided on the surface thereof, and a colored or colorless ink is further provided between the plastic film and the base ink layer and / or between the base ink layer and the water-based ink receiving layer. A plastic packaging material comprising a layer. 3. A method according to claim 1, wherein at least a part of the plastic film contains 0 to less than 15% by weight of a titanium oxide pigment,
An opaque or translucent colored base ink layer is formed with an ink comprising a solvent in an amount of 40% by weight, a resin binder of 5 to 50% by weight, and a total of 100% by weight, and a water-based ink containing a hydrophilic polymer on the surface thereof. A plastic packaging material comprising a layer. 4. A plastic film having a thickness of 9 to 12
The plastic packaging material according to any one of claims 1 to 3, wherein the plastic packaging material is at least one selected from a 0 μm polyethylene film, a polypropylene film, a polyvinylidene chloride film, a polyester film, a polyamide film, and a laminate thereof. 5. The plastic packaging material according to claim 1, wherein the thickness of the base ink layer (based on solid content, the same applies hereinafter) is 0.5 to 12 g / m ² . 6. The plastic packaging material according to claim 1, wherein the base ink layer contains water-absorbent resin particles and / or soybean protein powder. 7. The aqueous ink receiving layer has a thickness of 0.5 to 1
Plastic packaging material according to claim 1 which is 2 g / m ^2. 8. The plastic packaging material according to claim 1, wherein the aqueous ink-receiving layer contains water-absorbent resin particles and / or soybean protein powder. 9. The plastic packaging material according to claim 1, wherein the aqueous ink receiving layer contains spherical polyethylene wax and / or spherical cationic resin particles. 10. The plastic film envelope according to claim 1, wherein the base ink layer and the aqueous ink receiving layer are formed on a part of the surface of the plastic film.
Plastic packaging material according to the item. 11. The plastic packaging material according to claim 2, wherein the colored ink layer comprises a gold ink, a silver ink or a yellow ink. 12. The plastic packaging material according to any one of claims 1 to 11, wherein the plastic packaging material is formed in the shape of an envelope, and the individual information is to be entered in a place where it is to be entered. 13. An envelope made of a plastic film, wherein the laminated ink layer according to the above item is formed. 13. A printing method, wherein desired printing is performed by ink jet method using a water-based pigment ink at a place where individual information of the plastic film envelope according to claim 12 is to be written.