WO2001045957A1

WO2001045957A1 - Ink receiving element and method for printing

Info

Publication number: WO2001045957A1
Application number: PCT/JP1999/007164
Authority: WO
Inventors: Mizue Fukushima; Maki Takizawa
Original assignee: Citizen Watch Co., Ltd.
Priority date: 1999-12-21
Filing date: 1999-12-21
Publication date: 2001-06-28

Abstract

An ink receiving element having a substrate which exhibits no acceptability for ink, characterized as comprising, formed on the printing plane thereof, an ink-accepting layer containing, as a main component, a transparent and film-formable polymer prepared by polymerization of a monomer which is water-soluble and has a hydrophilic moiety in the molecule thereof. The ink receiving element can be suitably used, for example, for a dial plate of a clock, a scale plate of a measuring instrument, a plate for operation, and a scale plate of a speed meter or the like of an automobile or a motorcycle.

Description

Description Ink acceptance element and printing method

The present invention relates to an ink receiving element, and more particularly, to an ink receiving element printable with an aqueous ink using an ink jet method, in particular, plastic, glass, ceramic, and the like. The present invention relates to an ink receiving element provided with a base material having no ink receiving property, such as a mix or a metal. The ink receiving element of the present invention is used, for example, as a clock face, a scale plate of a measuring device, an operation panel, and the like, and a scale plate of a speedometer, such as an automobile and a motorcycle. can do. The invention also relates to a method for performing printing in such an ink receiving element. In the specification of the present application, the word “print” is used in the same meaning as “print”. Background art

At present, it is well known that the ink jet method is widely used as a printing technique or a recording technique. For example, in various measurement devices such as office automation devices such as word processors, personal computers, and facsimile devices, and medical measurement devices, etc. In order to print output information on recording paper, a printer using an ink jet method and an ink jet printer are widely used. Ink jet printers can use plain paper as recording paper, for example, so running costs are low, no additional steps such as transfer and fixing are required, and color printing is easy and clear. Is possible, and many other advantages.

Ink jet printer, usually the characteristics of the ink used for it Printing is performed on paper such as plain paper in consideration of the printing mechanism and printing mechanism. In recent years, recording media other than paper (such media are referred to as For example, printing is being performed on sheets, boards, and the like of hard materials such as metal, glass, and plastic.

However, the above-mentioned hard materials are hardly wetted by the ink jet ink, and are therefore difficult to fix the ink. Therefore, various improvements have been attempted. For example, the official gazette of Japanese Patent Publication No. 55-34771-2 is based on the ink jet recording method using a water-soluble ink. Discloses an ink jet recording method characterized in that an ink jet recording is performed before a finger dries. In other words, this method uses a bleeding phenomenon of the ink by spraying a water-soluble ink while the water content of the paint is sufficient to improve the thickness of the recording and the wettability of the ink particles. Is being improved.

Further, Japanese Patent Publication No. 55-34713 discloses that an emulsion-based paint having a pigment volume concentration of 20% or more is applied to a non-absorbing base material, dried, and then dried to form non-drying ink particles. It discloses a jet printing method characterized by high-speed, continuous and stable ejection from a thin nozzle of about 10 to 400 / m, and ink jet recording. That is, in this method, a porous coating film having a high pigment concentration is formed, thereby facilitating diffusion of the ink to the surface and the inside of the coating film.

In addition, Japanese Patent Publication No. 60-27589 discloses a method for forming an image on a plastic sheet surface by an ink jet method, which is one of the components of an ink colorant. A sublimable dye is used as part or all, and a resin that cures with ultraviolet rays is used as a dispersion medium. After the image is formed, the sheet is irradiated with ultraviolet rays, and the sheet is heated to increase the temperature. And at the same time Alternatively, it discloses a method of forming an image on a plastic sheet, which is characterized in that fixing is performed by performing the operation continuously. In other words, this method is intended to improve the permeability of a plastic sheet by using a sublimable dye, and to use an ultraviolet-curable resin as a dispersion medium of the dye, thereby obtaining an ultraviolet ray. As a result of the combined use of irradiation and heat fixing, wear resistance is given to the plastic sheet.

Further, Japanese Patent Application Laid-Open No. 9-314996 discloses that an aluminum oxide substrate has an anodic oxide film on the surface thereof, and that the film has excellent ink absorbability on the film. An ink jet recording aluminum plate having an ink receiving layer formed thereon is disclosed. The ink receiving layer is formed from a water-soluble polymer such as polyvinyl alcohol, acrylate polymer, carboxymethyl cellulose, starch, and casein to a thickness of 7 to 15 m. . The aluminum plate of the present invention forms an anodic oxide film between the base aluminum sheet and the ink receiving layer, thereby improving the adhesion strength of the ink receiving layer to the substrate and preventing deterioration of the substrate such as rust. We are trying to prevent it.

By the way, when manufacturing various clock faces, etc., usually, octopus printing and screen printing are performed using an oil-based ink on the surface of a metal plate or plastic plate coated with undercolor. Prescribed characters and symbols are printed. However, since this method is complicated and the manufacturing cost is high, it is desirable to employ the above-described ink jet method for printing a pattern, a character, a symbol, and the like. The ink jet method has advantages such as easy colorization and clear color printing as described above.

In the manufacture of dials and the like, when printing designs and the like by the ink jet method, several requirements must be satisfied. The first requirement is a substrate that does not have ink acceptability, such as a metal plate or a plastic plate. Water must be completely received and fixed on the surface, i.e., the ink jetted onto the substrate. This means that the ink must not adhere to the surface, run on the surface, or the ink after drying must be easily wiped off.

In order to satisfy this first requirement, it is conceivable to provide an ink-receiving layer on the substrate, but the ink-receiving layer must also satisfy the following important requirements.

1. Transparency

Since the texture of the groundwork is an important factor for improving design, etc., it is necessary to have sufficient transparency to reflect the dial painted surface and metallic luster. Therefore, it is usually preferable to form an ink receiving layer by dispersing porous filler particles in a transparent binder resin in order to improve the ink absorption speed and absorption amount. However, this method cannot be adopted because it hinders transparency.

2. Good ink absorption and fixability, no bleeding or color mixing

If these requirements are not met, not only can high print quality not be obtained, but the yield must be reduced.

3. Excellent environmental resistance

Clock faces and the like are often exposed to harsh environments, so it is essential that they have a high level of environmental resistance. For example, it is necessary to pass at least the following environmental tests. Each environmental test is described in detail below.

(1) Moisture resistance test: 400 V / 90% RH (relative humidity), 100 hours

② Light fastness test (dry and wet)…

Sunshine Ethermeter, 100 hours ③ Adhesion test (cross cut test)…

According to J I S D 0 2 0 2 8 .1 2

However, as far as the inventor knows, an ink jet printing method that can satisfy the above requirements when printing a pattern such as a dial by the ink jet method is still proposed. No ink receiving element suitable for such a printing method has been proposed. Also, the ink jet printing method described with reference to the above cannot satisfy these requirements.

For example, in the method disclosed in Japanese Patent Publication No. 55-34771, a water-soluble paint is applied to a recording medium in advance to form a coating film corresponding to the ink receiving layer according to the present invention. However, since this coating is colored, it does not satisfy the requirements of the ink-receiving layer such as transparency, and also denies the existence of an undercolor coating that can contribute to the improvement of design and the like. In addition, this method requires a special step of performing ink jet recording before the surface of the coating film does not dry to the touch, which complicates the recording process and equipment. I can't avoid it.

The method disclosed in Japanese Patent Publication No. 55-344713 also has a similar problem. That is, in this method, a paint having a high pigment volume concentration is applied and dried prior to printing of a dial or the like, and the resulting colored coating film corresponds to the ink receiving layer referred to in the present invention. is there.

In addition, the image forming method disclosed in Japanese Patent Publication No. 60-27589 does not have a transparent coating film corresponding to the ink receiving layer referred to in the present invention. Can not do. In addition, this method lacks versatility since the substrate is limited to plastic sheets.

Similarly, the aluminum plate for ink jet recording disclosed in Japanese Patent Application Laid-Open No. 9-314986 is said to have its base material limited to the aluminum plate. Lack of versatility in point. In addition to this drawback, the ink-receiving layer used is made of a very common water-soluble polymer, so the only effect obtained is an improvement in ink absorption, high printing quality, Can not meet requirements such as transparency and environmental resistance. Further, since it is necessary to interpose an anodized film, the effect of the undercolor coating is limited to the effect of the color derived from the anodized film, and the reflection of the texture expected by the present inventors cannot be obtained. Disclosure of the invention

An object of the present invention is to provide an ink receiving element having a substrate that does not itself have an ink receiving property, and particularly to provide an ink receiving element suitable for an ink jet method. .

It is another object of the present invention to provide an ink receiving layer having the same or greater size without dispersing porous filler particles in a transparent binder resin to form an ink receiving layer. An object of the present invention is to provide an ink receiving element capable of improving an absorption rate and an absorption amount.

Another object of the present invention is that when an undercoat is used as an undercoat, the coated surface and metallic luster can be reflected, high print quality can be realized, and environmental resistance is improved. The aim is to provide a good ink-accepting element.

Still another object of the present invention is to provide an ink receiving element having a high adhesion strength of the ink receiving layer to the substrate when the ink receiving layer is provided on the substrate.

Another object of the present invention is to provide a method for performing high-quality printing by an ink jet method on an ink receiving element having a substrate having no ink receiving property. .

These and other objects of the invention are set forth in the following detailed description. It will be easy to understand.

In one aspect, the present invention relates to an ink receiving element including a substrate having no ink receiving property per se, wherein the printing surface of the ink receiving element is transparent, water-soluble, and is contained in the molecule. Provided is an ink receiving element characterized by comprising an ink receiving layer containing, as a main component, a film-forming polymer formed by polymerization of a monomer having a hydrophilic portion.

In another aspect, the invention provides a method of printing on an ink-receiving element that includes a substrate that does not itself have ink-receiving properties.

An ink receiving element containing, as a main component, a film-forming polymer formed by polymerization of a transparent, water-soluble, monomer having a hydrophilic portion in its molecule, on the printing surface of the ink receiving element. The present invention provides a printing method characterized by performing printing by an ink jet method using a water-based ink after providing a layer. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view showing a preferred embodiment of an ink receiving element according to the present invention,

FIG. 2 is a cross-sectional view showing another preferred embodiment of the ink receiving element according to the present invention,

FIG. 3 is a cross-sectional view showing another preferred embodiment of an ink receiving element according to the present invention;

FIG. 4 is a cross-sectional view showing yet another preferred embodiment of an ink receiving element according to the present invention;

FIG. 5 is a schematic view showing one structural example of a film-forming polymer contained in the ink receiving layer of the ink receiving element of the present invention,

FIG. 6 is a chemical formula showing a specific example of the film-forming polymer of FIG. And

FIG. 7 is a schematic view showing another structural example of a film-forming polymer contained in the ink receiving layer of the ink receiving element of the present invention, and FIG. It is a chemical formula showing a specific example of a crosslinking monomer used for forming a film-forming polymer,

FIG. 9 is a schematic diagram showing the behavior of a photocurable polymer used before and after polymerization of a film-forming polymer,

FIG. 10 is a sectional view sequentially showing a preferred embodiment of the ink jet printing method according to the present invention,

FIG. 11 is a schematic diagram showing a method of measuring a dynamic contact angle used for evaluating hydrophilicity.

FIG. 12 is a plot of the relationship between UV-ozone treatment time and dynamic contact angle, and

FIG. 13 is a plot of the relationship between the ultraviolet-ozone treatment time and the color difference ΔE * ab. BEST MODE FOR CARRYING OUT THE INVENTION

The ink receiving element according to the present invention comprises at least a substrate and an ink receiving layer provided on a printing surface of the substrate (where desired printing is performed). You. The ink receiving layer is usually provided on only one side of the substrate, but may be provided on both sides of the substrate, if necessary.

FIG. 1 shows a typical example of the ink receiving element of the present invention. In the ink receiving element 10, the ink receiving layer 2 is directly provided on one surface of the substrate 1. The ink receiving layer 2 is sprayed with ink drops 9 flying from an ink jet printer (not shown). Here, the substrate 1 is formed from any material and in any form. However, as will be understood from the above description, those that have sufficient ink acceptability by themselves, such as paper or similar recording paper, are excluded from the target. Is done. In the illustrated example, a base material made of a plastic material is used.

In the practice of the present invention, a suitable material for the substrate 1 is a plastic material, for example, a polyester resin, a polyolefin resin, a polyvinyl chloride, an acrylic resin, a phenol resin, etc. Ceramics, metals, such as solid glass, silicate glass, etc., such as aluminum, steel, copper, titanium, and wood. The substrate used in the practice of the present invention does not itself have an ink accepting property, and can be made of a material other than those described above as long as the effects of the present invention are not adversely affected. May be.

The shape of the base material 1 can be a plate (plate), a block, a sphere, a cylinder, or the like, in addition to the sheet as shown in FIG. An uneven pattern or the like may be provided. Therefore, the size of the base material 1 can be arbitrarily changed according to the target printed matter.

First, the ink receiving layer 2 must be transparent. This is because if it is translucent, opaque, or colored, it is not possible to improve the design, etc., by reflecting the texture of the base. For example, in the case of a clock face, there is a metal plate and an undercolor coating (coating film) provided on it, on which patterns, characters, and symbols are printed. However, if the ink receiving layer is not transparent, the texture cannot be improved by reflecting the metallic luster and the undercolor painted surface. Therefore, the ink receiving layer 2 used in the present invention is filled with porous inorganic material particles and the like generally mixed in the prior art to increase the ink absorption rate and absorption amount. Wood Not included. Of course, the ink receiving layer 2 may optionally contain an appropriate amount of an additive, for example, a coating aid, as long as the transparency is not adversely affected. Usually, the transparency of the ink receiving layer 2 is preferably 90% or more when viewed with respect to the transmittance of light having a wavelength of 500 nm (measured by a spectrophotometer). Preferably, it is 95% or more.

The ink receiving layer 2 is formed by polymerization of a water-soluble monomer having a hydrophilic part in its molecule (hereinafter also referred to as “water-soluble monomer”) as a main component. It is essential to contain a film-forming polymer. In the present invention, the ink-receiving layer is formed from the film-forming polymer having such a specific structure, so that a filler or other additives may be mixed or mixed as in the conventional ink-receiving layer. A transparent film can be formed without any treatment, the affinity with ink is large, a large amount of ink can be absorbed quickly, and there is no color bleeding or color mixing. Various effects such as excellent environmental resistance can be obtained. The film-forming polymer is usually prepared by preparing a film-forming composition containing a water-soluble monomer and other essential components, and polymerizing the water-soluble monomer in the film-forming composition. The ink-receiving layer can be formed by applying a resin solution containing such a film-forming polymer on a substrate and drying the resin solution.

FIG. 5 is a schematic view showing one structural example of a film-forming polymer derived from the above-mentioned water-soluble monomer contained in the ink receiving layer. As shown in the figure, a hydrophilic part A is contained in a part of the main chain L of the film-forming polymer. In the illustrated example, the hydrophilic portion A is bonded to a part of the main chain L of the film-forming polymer. However, as long as the desired effect can be obtained, the bonding form of the hydrophilic portion A The amount can be changed arbitrarily Noh. FIG. 6 shows a typical example of the film-forming polymer shown in FIG. 5, which is a polymer formed from N, N-dimethylaminophenol as a water-soluble monomer. It is a chemical formula. In the formula, n represents the number of repeating units of the N, N-dimethylacrylamide monomer, and Me represents a methyl group. In the case of this polymer, each NC = 0 can function as the hydrophilic part A.

The water-soluble monomer used for forming the film-forming polymer is not particularly limited as long as it satisfies predetermined requirements, but the hydrophilic portion to be contained in the molecule is preferably as described above. An amide group. Accordingly, water-soluble monomers suitable for the practice of the present invention are not limited to those listed below, but are substituted or unsubstituted acrylamide compounds, such as acrylamide, Substituted or unsubstituted metaacrylamides, such as N—methylacrylamide, N—ethylacrylamide, N, N—dimethylacrylamide, N, N—getylacrylamide N, N-methylmethacrylylamide, N, N-ethylmethacrylylamide, N, N—Dimethylmethacrylylamide, N, N— Compounds that can be made water-soluble by copolymerizing with acetyl morpholine or other water-soluble monomers such as getyl methacrynoleamide, for example, diacetone Acrylamide, N-Isopropylpyrroleamide, and the like. Among such water-soluble monomers, N, N-dimethylatarylamide is particularly suitable in terms of its ability to form a transparent film and print quality.

The thickness of the ink-receiving layer 2 composed of a film-forming polymer derived from a water-soluble monomer is not particularly limited, and the desired effect and the amount of ink to be received by the ink-receiving layer 2 are not particularly limited. It can be changed in a wide range depending on the situation. The thickness of the ink receiving layer 2 is usually several / zm to It is preferably in the range of 50 m, more preferably in the range of 5 to 30 m. In a case where a relatively large amount of ink needs to be received, the thickness of the ink receiving layer 2 may be more than 50 μm.

The step of polymerizing a water-soluble monomer to form a corresponding film-forming polymer can be basically carried out using a conventional polymerization method suitable for each monomer. For example, the polymerization can be carried out by reacting a predetermined amount of the selected water-soluble monomer in the presence of a polymerization initiator in a nitrogen atmosphere at an elevated temperature of 50 to 70 ° C. The polymerization initiator used here is preferably a water-soluble polymerization initiator. Suitable polymerization initiators include, for example, 2,2'-azobis (2-amidinopropane) dihydrochloride, 4,4'-azobis (4,4-cyanovaleric acid), 2,2'-azobis [2— (2—imidazolin—2—yl) propane] dihydrochloride, 2,2′-azobis [2— (2—imidazolin-1-2-yl) prono. ] Disulfate dihydrate, 2,2'-azobisisobutylamidonihydrate, persulfate and the like. Further, if necessary, a polymerization accelerator and other additives may be added to the film forming composition. In addition, since the polymerization conditions of such a water-soluble monomer are described in many technical documents in the field of polymer chemistry, please refer to those technical documents for details.

The ink receiving element according to the present invention may have various layer configurations within the scope of the present invention, in addition to the eyebrow configuration described above with reference to FIG. 2 to 4 each show another preferred embodiment of the ink receiving element of the present invention. Although not shown, the ink receiving element of the present invention may include other layers commonly used in the ink receiving element, such as a light reflecting layer and an overcoat, if necessary. It may additionally have a tool or the like.

In the ink receiving element 10 shown in FIG. 2, the undercolor coating 3 is disposed between the plastic substrate 1 and the ink receiving layer 2. By arranging the colored undercoat 3 under the transparent ink receiving layer 2, it is possible to improve the texture derived from the undercoat 3. For example, if a metallic coating is applied as the undercolor coating 3 or a pearl my coating is applied, the metallic luster can be visually recognized through the transparent ink receiving layer 2. Thus, a composition can be achieved in which characters, symbols, and the like to be printed later emerge.

The formation of the undercolor coating 3 can be optionally carried out using conventional techniques. For example, a solution or powder composed of a dye, a pigment, a solvent, or the like is coated on a substrate with a desired thickness and pattern by coating, painting, or the like, and then cured. Can be formed. Coating can be performed by, for example, roll coating or brush coating, and coating can be performed by electrodeposition coating, electrostatic coating, or the like. If necessary, a metal deposition film or an anodic oxide film may be formed instead of the undercolor coating.

The thickness of the undercolor coating 3 can be changed in a wide range according to the type of the ink receiving element, etc., but usually the range of 10 to 200 / zm is preferable, and furthermore, Preferably, it is in the range of 20 to 100 zm. The thickness of the undercolor coating 3 may be outside the above range depending on the type of film forming method to be adopted.

In the ink receiving element 10 shown in FIG. 3, the undercolor coating 3 is arranged between the plastic base material 1 and the ink receiving layer 2 similarly to the ink receiving element 10 shown in FIG. In addition, clear paint 4 is applied to the surface of undercolor paint 3. The clear coating 4 has, for example, an effect of further improving the color effect of the undercoat 3 of the base. Clear coating is an example For example, it can be performed by applying a urethane-based, acrylic-based, or epoxy-based clear paint and curing. If necessary, a white paint or the like may be used instead of the clear paint.

In the ink receiving element of the present invention, the undercoat 3 is formed as described above, or otherwise, after the undercoat 3 is formed and the clear coat 4 is further formed, It is preferable to further apply a hydrophilic treatment to suppress the hydrophobicity of these coatings. The hydrophilic treatment can be performed by a usual hydrophilic treatment, for example, an ultraviolet ozone treatment, a treatment with a coupling agent, an etching treatment, and the like. In particular, an ultraviolet ozone treatment is useful. This treatment imparts high hydrophilicity to the surface of the ink receiving element in the course of manufacture, so that the ink receiving layer can be attached to the surface with higher adhesion.

The ink receiving element 10 shown in FIG. 4 is an example in which a metal base material 11 is used as the base material instead of the plastic base material. In the example shown in the figure, a brass base material 11 with a detent 12 on its periphery is used. The undercoat 3 and the ink-receiving layer 2 are sequentially coated on the substrate 11 similarly to the ink-receiving element 10 in FIG. Although not shown, the ink receiving element 10 preferably has, as a base of the ink receiving layer 2, a clear coating that has been subjected to a hydrophilic treatment.

The ink-receiving layer, which plays the most important role in the ink-receiving element of the present invention, is a film formed by polymerization of a water-soluble monomer having a hydrophilic portion in its molecule (a water-soluble monomer). Contains a forming polymer as a main component. The film-forming polymer is typically a homopolymer formed by polymerization of a water-soluble monomer as described above, and if desired, the water-soluble monomer and another polymer. It may be a copolymer of a water-soluble monomer. By making this film-forming polymer in the form of a copolymer, for example, it is possible to improve the moisture resistance. In addition, additional effects such as improvement of water resistance and prevention of deterioration of print quality can be obtained. Further, the film-forming polymer of the present invention can be in the form of a mixture with another polymer.

According to a preferred embodiment of the present invention, the film-forming polymer, which may be in the form of a copolymer or a mixture, is not limited to those shown below,

1. a copolymer formed by polymerization of a water-soluble monomer and a water-soluble cross-linkable monomer having a hydrophilic group in its molecule,

2. A mixture of a homopolymer derived from a water-soluble monomer, a water-soluble photocurable polymer having a hydrophilic group and a photopolymerizable functional group in its molecule, and

3. A copolymer formed by polymerization of a water-soluble monomer and a water-soluble monomer having a hydrophilic group in its molecule, and a water-soluble copolymer having a hydrophilic group and a light A mixture of a photocurable polymer having a polymerizable functional group,

is there

The copolymer according to the above item 1 (hereinafter referred to as “first copolymer”)

) Is a copolymer formed by polymerization of a water-soluble monomer and a crosslinkable monomer. The crosslinkable monomer used here must have a plurality of crosslinking points in the molecule in addition to being water-soluble. The number of cross-linking points is preferably at least two in the molecule.

Crosslinkable monomers suitable for forming the first copolymer and having two or more crosslink points in the molecule are not limited to those listed below, but include methylene bisacrylamide, methyl Len bismethacrylorea amide, bisacrylyl amide acetic acid, N—methylol acryloamide, N—methylol methacrylamide, N, N '— (1,2—dihydroxy ) Acrylamide-based or methacrylamide-based crosslinkable monomers such as ethylene bisacrylamide and triacryloformamide. In place of such a crosslinkable monomer, the molecule has two or more crosslink points in the molecule, and at the same time, at least a plurality of ethylene glycol chains and / or propylene. Use water-soluble acrylate or methacrylate monomers having a glycol chain, such as diacrylate, dimethacrylate, triacrylate, trimethacrylate, etc. May be.

The polymerization for forming the first copolymer can be carried out under general polymerization conditions using a conventional polymerization method, similarly to the case of forming the homopolymer described above. .

FIG. 7 is a schematic diagram showing one structural example of a first copolymer (film-forming copolymer) derived from copolymerization of the water-soluble monomer and the above-mentioned crosslinkable monomer. As can be understood from the figure, this copolymer has a three-dimensional structure unlike the homopolymer having a linear structure shown in FIG. That is, in addition to the hydrophilic portion A being bonded to the main chain L of the copolymer, a crosslinkable monomer having a hydrophilic group B is formed by copolymerizing a water-soluble monomer and a crosslinkable monomer. The mer is bridging to provide a crosslinked structure. FIG. 8 is a chemical formula of polyethylene glycol diacrylate useful as a crosslinkable monomer in forming the first copolymer. The introduction of such a crosslinkable monomer is effective for imparting water resistance and for preventing deterioration of printing quality. In particular, those having an ethylene glycol chain in the molecule, that is, a hydrophilic group B in the formula of FIG. 8, have good compatibility with the water-based pigment-based ink, and thus have improved printing quality. Useful for

The polymer mixture according to the above item 2 (hereinafter referred to as “second mixture”) is obtained by polymerizing a water-soluble monomer to form a film-forming polymer. A mixture prepared by further adding a water-soluble, photo-polymerizable (photo-curable) polymer having a hydrophilic group and a photo-polymerizable functional group in its molecule. A mixture of the polymers described in paragraph 3

(Hereinafter, referred to as a “third mixture”) is a water-soluble and hydrophilic compound in the molecule after the water-soluble monomer and the above-mentioned crosslinkable monomer are polymerized to form the first copolymer. It is a mixture prepared by further adding a photocurable polymer having a group and a photopolymerizable functional group. In the case of a mixture of these polymers, the use of a photocurable polymer having a specific structure, which is water-soluble before photopolymerization and water-insoluble (ie, hydrophobic) after photopolymerization, makes it possible to obtain moisture resistance, Thus, the water resistance can be further improved.

The photocurable polymer that can be commonly used to form the second and third mixtures is preferably an ultraviolet curable polymer, and curing of such a polymer includes the same. Rather than immediately applying the resin solution on the substrate and drying it to form the ink-receiving layer, perform the necessary printing on the formed ink-receiving layer and then irradiate with ultraviolet light. It is preferable to carry out this. This is because curing before printing can adversely affect print quality. Conversely, if curing is performed after the printing process is completed, curing proceeds with the ink taken in, so that print quality can be improved.

The photocurable polymer needs to have a water-soluble group and a photoreactive group (preferably, a UV-reactive group) in the molecule in addition to being water-soluble. The hydrophilic group to be included in the molecule is, for example, a hydroxyl group, an ethylene glycol chain, a propylene glycol chain, or the like, and it is preferable that a plurality is included in one molecule. Similarly, the photoreactive group to be included in the molecule is, for example, a photopolymerizable functional group, for example, an acryl group, and a plurality is included in one molecule. This is preferred. The molecular weight of such a photocurable polymer can vary widely as long as the desired action is achieved. Therefore, the molecular weight can be as low as 300 000 from a low molecular weight such as an oligomer. Can be arbitrarily used up to those having a higher molecular weight.

For reference, such a photocurable polymer is commercially available under the following trade names.

Acrylic light-curing polymer

Product name “ALONIX TO—13 2 1”, “ALONIX TO—1 3 4 3” (both manufactured by Toagosei)

Acrylic photocurable polymer ...

Product name “NK Polymer B—15 16 S—11” (Shin Nakamura Chemical

)

FIG. 9 is a schematic diagram for easily explaining the change in water solubility before and after polymerization in the photocurable polymer. The photocurable polymer (I) before polymerization has a hydrophilic group C in its main chain and a photoreactive group D as a branched chain, and is therefore water-soluble. However, after the printing process is completed, the ink receiving layer holding the ink image is irradiated with light, such as ultraviolet light (UV), which can cause photopolymerization and curing of the photocurable polymer. Since a large number of photoreactive groups D are present in one molecule, they are cross-linked three-dimensionally and the hydrophilic part is reduced, so that they become water-insoluble (that is, hydrophobic). .

According to the present invention, in addition to the above-described ink receiving element, a printing method using the ink jet method in such an ink receiving element is also provided. The ink receiving element used in the method of the present invention is an ink receiving element including a substrate having no self-ink acceptability of the present invention. Is omitted.

The printing method of the present invention enumerates the preferred embodiments, It is on the street.

(1) A film-forming polymer, which is formed by polymerization of a transparent, water-soluble, monomer having a hydrophilic portion in its molecule, as a main component on the printing surface of the ink receiving element. After the ink receiving layer including the ink-receiving layer is provided, the ink-receiving layer is provided with the water-soluble monomer and other water-based ink in a printing method using an ink jet method. In the film-forming composition containing essential components, the film-forming polymer is formed by homopolymerization of the water-soluble monomer, and subsequently, the obtained resin solution is applied on a substrate and dried. , Printing method o

(2) A film-forming polymer, which is formed by polymerization of a transparent, water-soluble, monomer having a hydrophilic portion in its molecule, as a main component on the printing surface of the ink receiving element. After the ink-receiving layer is provided, the ink-receiving layer is homopolymerized from the water-soluble monomer in a printing method of performing printing by an ink jet method using an aqueous ink. After further adding a water-soluble photocurable polymer having a hydrophilic group and a photopolymerizable functional group in its molecule to the resin solution containing the polymer, the resin solution is applied on a substrate, Providing by drying, and curing the photocurable polymer by irradiation of light after completion of the printing step, a printing method o

(3) A film-forming polymer which is formed by polymerization of a transparent, water-soluble, monomer having a hydrophilic portion in its molecule on the printing surface of the ink receiving element, as a main component. After the ink receiving layer including the ink receiving layer is provided, the printing is performed by an ink jet method using a water-based ink. In a film-forming composition comprising a crosslinkable monomer having a hydrophilic group in its molecule and other essential components, the water-soluble monomer and the crosslinkable monomer A printing method, wherein the film-forming polymer is formed by one copolymerization, and subsequently, the obtained resin solution is applied on the substrate and dried.

(4) A film-forming polymer, which is formed by polymerization of a transparent, water-soluble, monomer having a hydrophilic portion in its molecule, as a main component on the printing surface of the ink receiving element. After the ink receiving layer is provided, the printing is performed by an ink jet method using an aqueous ink. In the printing method, the ink receiving layer is combined with the water-soluble monomer and the water-soluble monomer. In the resin solution containing a film-forming polymer derived from the copolymerization of a crosslinkable monomer having a hydrophilic group in its molecule, a water-soluble and hydrophilic group and a photopolymerizable functional group are added in the molecule. After further adding the photocurable polymer having the resin solution, the resin solution is applied to a substrate and provided by drying, and the photocurable polymer is cured by irradiation of light after completion of a printing process. Let the printing method.

(5) The printing method according to the above (2) or (4), wherein a UV-curable polymer is used as the photocurable polymer, and polymerization and curing are performed by irradiation with UV light after completion of the printing step.

(6) The printing method according to any one of (1) to (5) above, wherein the ink receiving layer is provided after applying an undercolor coating to a printing surface of the base material.

(7) The printing method according to the above (6), wherein after applying the undercolor coating, the surface is further subjected to a hydrophilic treatment.

(8) The printing method according to the above (7), wherein the hydrophilic treatment is an ultraviolet ozone treatment.

(9) The printing method according to any one of (1) to (8) above, wherein the water-soluble monomer is N, N-dimethylacrylamide. The ink jet printing method of the present invention will be described first with reference to FIG. The following describes an example of printing on a clock face having the same configuration as that of the ink receiving element 10 described above. In the following description, the alphabetic symbols enclosed in parentheses in each step correspond to the alphabetic symbols in FIG.

(A) Formation of undercolor paint on dial

One side of a plastic base material (polymer ester sheet) 1 is painted with the color of the dial, and a base color paint 3 is formed. In the illustrated example, a white urethane paint was applied by electrostatic coating.

(B) Hydrophilic treatment of undercolor paint

Apply a clear coat 4 on the surface of the white undercoat 3. The clear coating 4 can be formed, for example, by applying a urethane clear coating and drying. Next, the clear coating 4 is subjected to ultraviolet-ozone treatment to impart a predetermined level of hydrophilicity. Here, the obtained hydrophilicity is evaluated by dynamic contact angle measurement of pure water (advance contact angle and receding contact angle) as shown in FIG. For example, the advancing contact angle is

As shown in (I), drop pure water 22 onto the surface of test plate 21 with nozzle 24 (see arrow). Pure water 22 grows as it is supplied, as indicated by the arrows in the figure. Further, the receding contact angle is, as shown in FIG. 11 (II), the large amount of pure water once formed as described above.

It is performed by sucking pure water through nozzle 24 with two force plates. In the figure, water is drawn as indicated by the arrow.

In the case of the method of the present invention, the advancing contact angle is usually preferably 80 ° or less, more preferably 60 ° or less. Further, the receding contact angle is usually preferably 40 ° or less, more preferably 30 ° or less. Such a dynamic contact angle increases the time required for the ultraviolet-ozone treatment. It decreases with increasing pressure. Fig. 12 attached shows the case of UV-ozone treatment. 7 is a graph in which the relationship between the distance (minutes) and the dynamic contact angle (°) is plotted. In the figure, curve I represents the advancing contact angle (°), and curve II represents the receding contact angle.

In addition, when performing the UV-ozone treatment according to the method of the present invention, it is preferable to suppress the fading of the undercolor coating to a low level, and the fading is generally a general phenomenon in the field of color science. As described above, when expressed by the color difference ΔE * ab, it is desirable that the maximum value be 0.5. Figure 13 attached is a plot of the relationship between the time (minutes) of the UV-ozone treatment and the color difference ΔΕ * ab. For details of the color difference ΔE * ab, refer to CIE1976 L * a * b * color difference formula.

As can be understood from the graphs of FIGS. 12 and 13 described above, in the method of the present invention, although the time of the ultraviolet ray-ozone treatment varies depending on factors such as the intensity of the treatment, the time is usually different. In about 2 minutes, the effect appears, and from the viewpoint of suppressing fading, it is preferable to complete the processing in about 7.5 minutes, and a more preferable processing time is about 3 to 7 minutes. Range.

Note that, in the above-described process, the ultraviolet-ozone treatment is performed, but instead, the hydrophilicity may be imparted by a normal surface treatment such as cutting or etching.

(C) Formation of ink receiving layer

A film-forming polymer formed by copolymerization of a water-soluble monomer and a water-soluble, cross-linkable monomer having a hydrophilic group in its molecule; a water-soluble, hydrophilic group and a photopolymerizable functional group in its molecule; A transparent resin solution containing a photocurable polymer (a UV-curable polymer is used in this example) and other essential components is applied on the top clear coating film 4 of the substrate 1 Then, it is dried to evaporate the contained water. Here, the spray coating method was used to apply the resin solution. Other conventional coating methods, such as bar coating and printing, such as screen printing, can also be used. The ink receiving layer 2 and the ink receiving element 10 are completed.

(D) Printing by the ink jet method

On the transparent ink receiving layer 2 formed in the above step, full color printing of the clock pattern and the scale is performed by an ink jet printer. The ink used here is an aqueous pigment ink. After the ink has penetrated into the ink receiving layer 2, drying is performed to remove water and humectant components of the ink. This drying can be carried out using a conventional circulation thermostat, and the drying temperature is usually 60 ° C. or more and the drying time is 3 hours or more. The printing ink layer 5 is formed.

(E) UV curing

After drying the printing ink layer 5, ultraviolet rays (see arrows) are irradiated from an ultraviolet curing device to cure the ultraviolet curable polymer contained in the resin solution. Curing conditions depend on the absorption wavelength of the photopolymerization initiator to be used, but a general ultraviolet curing light source (wavelength: 300 to 450 nm) can be used. The ink is taken into the polymer by the curing of the ultraviolet curable polymer, and the printing ink layer 5 stably fixed is completed.

More specifically, in the ink receiving element and the printing method of the present invention, various inks can be used as a recording liquid, but preferably, an aqueous ink, particularly an ink jet. Water-based inks designed for recording, especially water-based pigment inks, can be used.

Water-based pigment inks, at least as commonly used for ink jet recording,

Dispersant,

Water-soluble liquid medium,

Moisturizer, Pigment, and

water,

Consists of Each ink component may be a commonly used ink component, and an outline thereof will be described below.

The dispersant is generally added to stably disperse the pigment in a particle size range of 50 to 200 nm.For example, a water-soluble resin having such properties, a surfactant, And those having a nonionic substituent such as an anionic group such as a carboxylate group, a sulfonate group, or a phosphate group as a hydrophilic part thereof, and a polyoxyalkylene group. Such a dispersant varies depending on the type of the pigment to be dispersed, but it is usually preferable that the dispersant has a molecular weight of several hundreds to several tens of thousands. And a variety of alkanolamines such as, for example, diethanolamine and triethanolamine. Examples of the counter ion species of the dispersant other than alkanolamine include alkali metals such as sodium and potassium, and ammonia. Other useful water-soluble liquid media include, for example, penetrants, pH modifiers, surface tension modifiers, viscosity modifiers, etc.

The humectant is used to adjust the stability of the dispersion system, the viscosity of the dried ink after water evaporation, and the like. For example, ethylene glycols such as ethylene glycol and polyethylene glycol; Propylene glycol such as pyrene glycol and polypropylene glycol

—, 1, 3-butanediol, and 3 — prono. And diols such as diols and pyrrolidones. Such humectants may be used alone, but taking into account the stability of the dispersion system, etc. In this case, it is preferable to use a mixed humectant system in which a plurality of humectants are mixed.

The pigment can be selected from a wide variety of known pigments that can satisfy the requirements such as the required color tone and compatibility with the dispersant, and can be used in an appropriate amount. For example, a typical example of a black pigment is carbon black, a typical example of a blue pigment is a phthalocyanine pigment, a typical example of a red pigment is a quinacridone pigment, and a typical example of a yellow pigment is an azo pigment. It is. The above-mentioned ink components are mixed and kneaded at an arbitrary ratio according to factors such as an ink jet printer to be used and a type of printed matter, to obtain a solution having a proper viscosity for coating. be able to.

Further, the ink receiving element and the printing method of the present invention can be respectively advantageously used for producing various printed matter. Suitable prints include, but are not limited to, the dials of watches, the dials of meters attached to various vehicles and measuring instruments, and the like.

Example

Subsequently, the present invention will be described with reference to examples thereof. It should be understood that the present invention is not limited by the following examples.

Example 1

80 parts by weight of water was charged into the reaction vessel and purged with nitrogen. Next, 10 parts by weight of acrylamide (as a monomer having an amide group) and 0.01 parts by weight of ammonium persulfate (as a polymerization initiator) were added. Polymerization was carried out at 0 ° C. for 45 minutes. After the completion of the polymerization reaction, a solution obtained by dissolving 0 to 7 parts by weight of methylene bisacrylamide (as a crosslinkable monomer) in dimethylformamide was added. After 2 hours, add another 0.01 parts by weight of ammonium persulfate and add 1 part by weight. The polymerization reaction was continued over 2 hours. After the completion of the continuous polymerization reaction, 2.5 parts by weight of an acrylic light-curable polymer (trade name: NK Polymer-1 B-15 16 S-11) and 0.6 parts by weight Was added (trade name: Irgacure 1 1 7 3). A transparent resin solution for forming the ink receiving layer was obtained.

Example 2

The procedure described in Example 1 above was repeated, but in this example, the same amount of N, N-dimethylacrylamide was used instead of acrylamide, and the same amount was used instead of methylenebisacrylamide. Amount of polyethylene glycol # 600 diacrylate is used, and as an acrylic photocurable polymer, “NK polymer B—15 16 S—11” (product Was replaced with the same amount of “Aronix TO-1 3 4 3” (brand name). A transparent resin solution for forming the ink receiving layer was obtained.

Example 3

The procedure described in Example 1 above was repeated, but in this example, the same amount of N, N-dimethylacrylamide was used instead of acrylamide, and then methylenebisacrylamide was used instead. The same amount of polyethylene glycol # 600 dichlorate was used. A transparent resin solution for forming the ink receiving layer was obtained.

Example 4

The procedure described in Example 1 above was repeated, but in this example, the same amount of acryloyl morpholine was used instead of acrylylamide, and the same amount of 2,2 was used instead of methylenebisacrylylamide. — Using bis [41 (methacryloxy.polyethoxy) phenyl] propane and acryl-based photocurable polymer, “NK Polymer B—1516S—11” (Trade name) was replaced with the same amount of “Aronix TO—1343” (trade name). A transparent resin solution for forming the ink receiving layer was obtained. Was done.

Comparative Example 1

80 parts by weight of water was charged into the reaction vessel and purged with nitrogen. Then, 7 parts by weight of vinylpyrrolidone, 3 parts by weight of N, N-dimethylacrylamide and 0.3 part by weight of 2,2′-azobis (2-amidinoprono) dihydrochloride ( (As a polymerization initiator), and polymerization was carried out at 70 ° C. for 45 minutes. A clear resin solution was obtained.

Comparative Example 2

A transparent resin solution was obtained by dissolving 10 parts by weight of polyvinyl alcohol (degree of saponification: 100%, degree of polymerization: 170,000) in 90 parts by weight of water.

Comparative Example 3

80 parts by weight of water was charged into the reaction vessel and purged with nitrogen. Next, 10 parts by weight of acrylamide and 0.01 part by weight of ammonium persulfate (as a polymerization initiator) were added, and polymerization was carried out at 60 ° C. for 45 minutes. A clear resin solution was obtained.

Comparative Example 4

80 parts by weight of water was charged into the reaction vessel and purged with nitrogen. Next, 10 parts by weight of N, N-dimethylacrylamide and 0.01 part by weight of ammonium persulfate (as a polymerization initiator) were added, and the mixture was polymerized at 60 ° C for 45 minutes. Was done. After the completion of the polymerization reaction, a solution obtained by dissolving 0.7 parts by weight of methylenebisacrylamide (as a crosslinkable monomer) in dimethylformamide was added. Two hours later, 0.01 parts by weight of ammonium persulfate was further added, and the polymerization reaction was continued for 12 hours. A clear resin solution was obtained.

Example 5

Trees prepared in each of Examples 1 to 4 and Comparative Examples 1 to 4 The fat solution was applied to a white dial using Barco overnight and dried at 60 ° C for 3 hours. The resulting ink receiving layer was tested according to the following procedure.

(1) Film characteristics test

The white dial was stored at room temperature (23-25 ° C), low humidity (less than 20%) for one week, and dried. The ink-receiving layer after drying was visually observed. A sample without any defect was evaluated as “〇 (pass)”, and a film with peeling or cracking was evaluated as “X (fail)”.

(2) Printing test

With an ink jet printer equipped with an aqueous pigment ink, full-color prints were made on a white dial. The state of printing was visually observed, and a sample without any defect was evaluated as “〇 (pass)”, and a sample with blurred or mixed color was evaluated as “X (fail)”.

(3) Adhesion test

The adhesion of the ink-receiving layer to the white dial was evaluated by a cross-cut test (according to JIS D 0 202.12). A grid was cut into the ink receiving layer with a cotter, and an adhesive tape was applied. After a predetermined time, the adhesive tape was peeled off, and the presence or absence of peeling of the ink receiving layer was examined. Those with no peeling were marked with “〇 (pass)” and those with peeling were marked with “X (fail)”.

(4) Light fastness test

The white dial was mounted vertically on a Sunshine II meter (light source: power clamp) and left for 100 hours under dry conditions (normal humidity) or wet conditions (under saturated steam). . The symbol on the white dial after standing without any fading was marked with "〇 (pass)", and the one on which fading was recognized was marked with "X (fail)".

(5) Moisture resistance test The white dial was placed horizontally and vertically on an environmental testing machine (constant temperature and humidity chamber) and left at 40 ° C / 90% RH (relative humidity) for 100 hours. The symbol on the white dial after leaving the pattern unchanged was marked with “〇 (pass)”, and the one with a change in picture flow etc. was marked as “X (fail)”. Table 1 below summarizes the results of each of the tests (1) to (5) described above.

Table 1

Example finolem Printing Adhesion Light resistance test Moisture resistance test No.Characteristics test sS

Example 1 〇〇〇〇〇〇〇 Example 2 〇〇〇〇〇〇〇 3 Example 3 〇〇〇〇〇〇〇 Example 4 〇〇〇〇〇〇〇〇 Example 4

Comparative Example 2 〇 X 〇

Comparative Example 3 〇〇〇〇 X X X Comparative Example 4 〇〇〇〇 X 〇 X Note) “One J means that measurement was not possible.

As described above, according to the present invention, for example, it can be used as a clock face, a scale plate such as a measuring device, an operation panel, and the like, and a scale plate such as a speedometer of an automobile, a motorcycle, and the like. An ink receiving element capable of performing printing and a method of performing printing by an ink jet method using the ink receiving element are provided.

Claims

The scope of the claims

1. In an ink-receiving element including a substrate having no ink-receiving property per se, a monomer that is transparent, water-soluble, and has a hydrophilic portion in its molecule on the printing surface of the ink-receiving element. An ink-receiving element comprising an ink-receiving layer containing, as a main component, a film-forming polymer formed by polymerization of an ink.

2. In addition to the film-forming polymer, it further comprises a water-soluble, photocurable polymer having a hydrophilic group and a photopolymerizable functional group in its molecule. The ink receiving element according to claim 1.

3. The ink according to claim 1 or 2, wherein the film-forming polymer is a homopolymer formed by polymerization of the water-soluble monomer. Acceptance element.

4. The film-forming polymer is a copolymer formed by polymerization of the water-soluble monomer and a water-soluble cross-linkable monomer having a hydrophilic group in its molecule. The ink receiving element according to claim 1 or 2.

5. The photocurable polymer according to claim 2, wherein the photocurable polymer is an ultraviolet curable polymer, and is cured by irradiating ultraviolet rays after the completion of a printing process. Link accept element.

6. An undercolor coating is applied to a printing surface of the base material, and this is used as a base of the ink receiving layer. Ink acceptance element described in section.

7. The ink receiving element according to claim 6, wherein the undercolor coating is subjected to a hydrophilic treatment.

8. The hydrophilic treatment is an ultraviolet ozone treatment. The ink receiving element according to claim 7.

9. The ink-receiving element according to any one of claims 1 to 8, wherein the water-soluble monomer is N, N-dimethylacrylamide. .

10. The ink printing method according to claim 1, wherein the ink printed on the ink receiving layer is a water-based pigment ink, and the pigment ink is printed by an ink jet method. An ink-receiving element according to any one of paragraphs 9 to 9.

1 1. In a method of printing on an ink receiving element including a substrate having no ink receiving property by itself,

An ink receiving element containing, as a main component, a film-forming polymer which is formed by polymerization of a transparent, water-soluble, monomer having a hydrophilic portion in its molecule, on the printing surface of the ink receiving element. A printing method characterized in that after forming a layer, printing is performed by an ink jet method using a water-based ink.

12. The ink-receiving layer is formed by forming the film-forming polymer by homopolymerization of the water-soluble monomer in a film-forming composition containing the water-soluble monomer and other essential components, The printing method according to claim 11, wherein the obtained resin solution is applied on the substrate and dried to provide the resin solution.

13. The ink-receiving layer is prepared by adding a water-soluble photocurable polymer having a hydrophilic group and a photopolymerizable functional group in its molecule to a resin solution containing the film-forming polymer. After further addition, the resin solution is applied on a substrate and dried to provide the resin solution, and

The photocurable polymer is polymerized and cured by light irradiation after the completion of the printing step,

The printing method according to claim 12, wherein the printing method is characterized in that:

14. The ink-receiving layer may be formed of the water-soluble monomer, the water-soluble monomer, a cross-linkable monomer having a hydrophilic group in its molecule, and other essential components. The film-forming polymer is formed by copolymerization of the cross-linkable monomer, and subsequently, the obtained resin solution is applied on the substrate and dried. The printing method according to claim 11.

15. The ink-receiving layer is formed by adding a water-soluble resin containing the film-forming polymer to a water-soluble resin and having a hydrophilic group and a photopolymerizable functional group in its molecule. After the addition, the resin solution is applied on a base material and dried to provide the resin solution; and

The printing method according to claim 14, wherein the printing method is characterized in that:

16. The method according to claim 13, wherein an ultraviolet-curable polymer is used as the photocurable polymer, and polymerization and curing are performed by irradiation of ultraviolet light after completion of a printing process. Printing method described in section 15

17. The ink receiving layer according to any one of claims 11 to 16, wherein the ink receiving layer is provided after a base color is applied to a printing surface of the base material. Printing method.

18. The printing method according to claim 17, wherein after the undercolor coating is applied, the surface is further subjected to a hydrophilic treatment.

19. The printing method according to claim 18, wherein the hydrophilic treatment is an ultraviolet ozone treatment.

20. The printing method according to any one of claims 11 to 19, wherein the water-soluble monomer is N, N-dimethylacrylamide.