JP4309318B2 - Ink-receiving layer forming composition and substrate for printing - Google Patents

Description

  The present invention relates to a composition for forming an ink receiving layer capable of printing character information and image information by an ink jet method. The present invention also relates to a substrate to be printed having an ink receiving layer formed using the composition for forming an ink receiving layer.

  In recent years, CD-type and DVD-type optical recording media capable of writing and reading information with a laser have begun to spread widely. Companies dealing with a small amount of various types of optical recording media are required to be able to print images and characters representing the recording contents of the optical recording media by the inkjet method. Furthermore, as the use of optical recording media has spread to general users, printers capable of printing on such recording media have been released, and the label side of the disc (the side opposite to the optical writing / reading side) has been released. For the purpose of designing the surface), there is an increasing demand for printing not only characters representing recorded contents but also high-quality images such as photographs.

  Against this background, many optical recording media having a label surface that can be printed by an ink jet printer have been sold. As the ink used in the inkjet method, a water-based ink is usually used. Therefore, an ink receiving layer having water absorption is formed on the surface of the label surface. As the composition for forming the ink receiving layer, a radiation curable composition such as ultraviolet ray is often used from the viewpoint of productivity.

  The ink receiving layer is required to have image preservability such as quick drying of ink, sharpness of image, and water resistance. As such a coating composition, Patent Document 1 includes a coating composition that promotes ink absorption and improves resolution by providing a concavo-convex structure on the surface of a hydrophilic ink-receiving layer.

  In addition, a coating composition has been proposed that improves quick drying and sharpness of images by adding an inorganic filler or an organic filler to a hydrophilic resin. Patent Document 2 includes a coating composition containing a porous smectite as an inorganic filler.

  Further, Patent Document 3 includes a coating composition containing porous alumina as an inorganic filler.

  As the organic filler, Patent Document 4 includes a coating composition containing water-absorbing resin particles.

  Patent Document 5 includes a coating composition using a natural material as the organic filler.

Many coating compositions containing organic cations have also been proposed in order to improve the water resistance of the ink receiving layer. An acid dye is generally used as a dye used for ink in the ink jet system. For this reason, it is an attempt to fix dye molecules having opposite charges by adding an organic cation to the ink receiving layer. As a specific example, Patent Document 6 is cited.
JP-A-6-60432 Japanese Patent Laid-Open No. 7-272441 JP 11-213445 A JP 7-169100 A JP-A-10-259340 Japanese Patent Laid-Open No. 2001-311022

  However, in the ink receiving layer to which the above-described conventional inorganic filler or organic filler is added, it may be difficult to achieve both image drying characteristics, image sharpness, and water storability characteristics such as water resistance. In addition, when a porous inorganic filler is mixed in the resin, the resin penetrates into the pores of the filler, so that sufficient water absorption is not obtained and drying properties are deteriorated. In some cases, bleeding is likely to occur. Further, when an organic filler having high water absorption is used, the ink absorbability is improved, but on the other hand, the drying property and the water resistance tend to be inferior. Therefore, there is a demand for an ink-receiving layer that is further improved in quick drying properties, image sharpness, and water resistance.

  An object of the present invention is to provide a composition for forming an ink receiving layer capable of forming an ink receiving layer excellent in image storability such as quick drying, image sharpness, and water resistance.

  Another object of the present invention is to provide a substrate to be printed having an ink receiving layer formed using the above-described composition for forming an ink receiving layer.

  The composition for forming an ink receiving layer of the present invention includes (A) a monomer component containing a monofunctional monomer, and (B) a filler containing an egg white component.

  The ink-receiving layer-forming composition of the present invention can further take the following aspects.

  In the composition for forming an ink receiving layer of the present invention, the component (A) can further contain a bifunctional or higher functional monomer.

  In the composition for forming an ink receiving layer of the present invention, the component (B) can be dried egg white particles.

  In the composition for forming an ink receiving layer of the present invention, the component (B) may be one in which the surface of inorganic particles or organic particles is covered with an egg white component.

  In the composition for forming an ink receiving layer of the present invention, the average particle size of the component (B) may be 0.01 to 30 μm.

  In the composition for forming an ink receiving layer of the present invention, the content of the component (B) can be 5 to 200 parts by weight with respect to 100 parts by weight of the component (A).

  The composition for forming an ink receiving layer of the present invention further contains a polymerization initiator, and the content of the polymerization initiator is 0.01 to 10 parts by weight with respect to 100 parts by weight of the component (A). be able to.

The substrate to be printed of the present invention comprises a supporting substrate,
An ink receiving layer provided on the support substrate and formed using the ink receiving layer forming composition of the present invention.

  In the substrate to be printed according to the present invention, the support substrate may be an optical recording medium that performs optical writing / reading.

  The composition for forming an ink receiving layer of the present invention can be suitably used for forming an ink receiving layer that is printed by an inkjet method. The ink receiving layer forming composition of the present invention contains a filler containing an egg white component as the component (B). Since the egg white component is a water-soluble protein, it has a water absorption property, and since it has an amino group in its molecule, it can enhance the fixing property of the ink. Therefore, according to the ink receiving layer forming composition of the present invention, it is possible to form an ink receiving layer excellent in image storability such as quick-drying property, image sharpness, and water resistance.

  An example of the embodiment of the present invention will be described below.

  The composition for forming an ink receiving layer of the present invention includes (A) a monomer component containing a monofunctional monomer, and (B) a filler containing an egg white component.

  First, the component (A) will be described.

  Examples of the monofunctional monomer contained in the component (A) include N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylformamide, N, N-dimethylacrylamide, 2-hydroxyethyl (meth) acrylate, and 2-hydroxypropyl. (Meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, butanediol monoacrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, N, N -Diethylaminoethyl acrylate, N, N-dimethylaminoethyl (meth) acrylate, 2-hydroxyethyl vinyl ether, methoxy-polyethylene glycol mono (meth) acrylate Mention may be made of the monomer. Mixtures of these monomers can also be used.

  Further, N-vinylacetamide, N-hydroxymethylacrylamide as monomers that are solid at room temperature, and trimethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- () as monomers having a quaternary ammonium salt in the side chain. Mention may be made of acryloyloxy) propylammonium chloride, trimethyl-2-hydroxy-3- (acryloyloxy) propylammonium chloride, trimethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-2- (acryloylamino) propylammonium chloride. it can. These solid monomers can also be used by dissolving in the liquid monomer.

  The component (A) of the present invention may further contain a bifunctional or higher polyfunctional monomer.

  Although it does not specifically limit as a polyfunctional monomer, For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethyleneglycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol Tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate , Neopentyl glycol di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, bisphenol A di (meth) acrylate, Cyanuric acid trihydroxyethyl di (meth) acrylate, isocyanuric acid trihydroxyethyl tri (meth) acrylate, ethylene oxide modified product or propylene oxide modified product of these compounds, (poly) ethylene glycol di (meth) acrylate, (poly ) Propylene glycol di (meth) acrylate, various urethane acrylates, epoxy acrylates, polyester acrylates and the like. Mixtures of these monomers can also be used.

  The polyfunctional monomer serves as a cross-linking agent and is used for controlling coating film hardness, coating water absorption and water resistance. In the component (A), when both a monofunctional monomer and a polyfunctional monomer are used, the monofunctional monomer is 70 to 99% by weight, and the bifunctional or higher polyfunctional monomer is 1 to 30% by weight. preferable. More preferably, the monofunctional monomer is 80 to 98% by weight and the polyfunctional monomer is 2 to 20% by weight.

  When the polyfunctional monomer is less than 1% by weight, problems may occur in the curability of the composition and the strength of the coating film, and sufficient water resistance may not be obtained. On the other hand, if it exceeds 30% by weight, the printability may be deteriorated due to a decrease in water absorption of the obtained ink receiving layer. Further, the substrate may be warped or the adhesiveness may be reduced due to curing shrinkage.

  In consideration of applying the component (A) to the support substrate, the component (A) is preferably liquid. In this case, a monomer that is liquid per se or a solution obtained by dissolving a solid monomer in a liquid monomer can be used. Further, when thermosetting is used as a curing method, a monomer component obtained by dissolving a solid monomer in a known organic solvent may be used.

  Next, the filler containing (B) egg white component will be described.

  In the present invention, the egg white component means a dried egg white liquid until the water content becomes 20% or less. The raw egg white liquor is the one in which the shelled egg is broken and the yolk is removed, the frozen egg white is thawed, hydrolyzed by enzyme treatment, desalted, and lysozyme. Those obtained by removing the components, those obtained by chemically modifying egg white protein with fatty acids or saccharides, those obtained by desugaring with enzymes, yeasts, bacteria, or the like can be used. In addition, the egg white component referred to here includes a case where a contaminant other than the egg white component, for example, an egg yolk component is slightly included.

  As the component (B), dry egg white particles that are egg white components themselves and particles in which the surfaces of other fillers are covered with egg white components can be used.

  As the dried egg white particles, commercially available dried egg white particles are used. The dried egg white particles are obtained by drying the egg white liquid, and a known method is used as a method for drying the egg white liquid, and examples thereof include conventional methods such as spray drying, freeze drying, and shallow plate drying. Moreover, after drying, the dried product may be pulverized as necessary. Dry egg white particles that have been dried and then stored for the purpose of sterilization may be used. In addition, egg white components obtained by re-precipitation of a shelled egg obtained by breaking the egg yolk and thawing frozen egg white into a water-soluble organic solvent such as alcohol or acetone can also be used.

  As particles having the surface of another filler covered with an egg white component, particles obtained by coating the surface of another organic filler or an inorganic filler with an egg white component can be used. Thus, the following can be mentioned as an advantage in coating the surface of another organic filler or an inorganic filler with an egg white component. In the case of using the above-mentioned dried egg white particles, the average particle size is preferably in a desired range (see the description below). However, in a general production method of dried egg white particles, it may be necessary to spend cost and time when controlling the average particle size with high accuracy. In such a case, if the surface of another organic filler or inorganic filler is covered with an egg white component, a filler in which the average particle diameter is controlled more efficiently can be obtained. Further, since the surface is covered with the egg white component, the fixing property of the dye can also be ensured.

  The coating on the surface of other fillers is a mixture of other fillers and eggs with shell eggs broken to remove egg yolk, those obtained by thawing frozen egg whites, or those obtained by re-dissolving the dried egg white particles in water. And it can carry out simply by drying.

  As described above, the surface of the egg white component is coated with organic fillers such as cellulose and silk protein, and inorganic fillers such as titanium oxide, zinc oxide, silica, alumina, calcium carbonate, calcium sulfate, and synthetic mica. Can be mentioned.

  In the composition for forming an ink receiving layer of the present invention, the average particle size of the component (B) is preferably 0.01 to 30 μm. More preferably, the average particle diameter of (B) component is 0.05-20 micrometers. When the average particle size is 0.01 μm, the water absorption tends to decrease, and the drying property and image sharpness may decrease. On the other hand, if it exceeds 30 μm, the smoothness of the coating film is deteriorated, the appearance is deteriorated, and the image sharpness may be lowered.

  Here, the average particle diameter is a particle diameter calculated by irradiating a particle group with laser light and obtaining a particle size distribution by calculation from an intensity distribution pattern of diffracted / scattered light emitted therefrom. As an apparatus for measuring the average particle diameter by this method, for example, a laser diffraction type particle size distribution measuring apparatus SALD2000A (manufactured by Shimadzu Corporation) can be mentioned.

  In the composition for forming an ink receiving layer of the present invention, the component (B) is preferably added in an amount of 5 to 200 parts by weight per 100 parts by weight of the component (A). The addition amount of the component (B) is more preferably 10 to 150 parts by weight. More preferably, it is 20-100 weight part. When the addition amount of the component (B) is less than 5 parts by weight, the image sharpness and water resistance tend to be insufficient. On the other hand, when it exceeds 200 parts by weight, the drying property tends to decrease. Furthermore, coatability may be reduced.

  The composition for forming an ink receiving layer of the present invention can be obtained by mixing the monofunctional and polyfunctional monomer mixture described above and a filler containing an egg white component.

  Furthermore, the composition for forming an ink receiving layer of the present invention may contain a polymerization inhibitor, a leveling agent, an antifoaming agent, a dispersing agent, a resin other than a monomer, and the like as necessary. Moreover, you may contain fine particles, such as a titanium oxide, a zinc oxide, a silica, an alumina, a calcium carbonate, a calcium sulfate, a synthetic mica, as a white pigment to such an extent that the objective of this invention is not impaired.

  The composition for forming an ink receiving layer of the present invention may further contain a photopolymerization initiator that generates radicals upon irradiation with radiation such as ultraviolet rays or visible rays. As these photopolymerization initiators, for example, acetophenone-based, benzoin-based, benzophenone-based, thioxanthone-based photopolymerization initiators can be used. Examples of the photoinitiating polymerization agent include 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzophenone, methyl o-henzoylbenzoate, 2,4. -Diethylthioxanthone, 4,4-bisdiethylaminobenzophenone, 2,2-diethoxyacetophene, 2-chlorothioxanthone, diisopropylthioxanthone, 9,10-anthraquinone, 2,2-dimethoxy-2-phenylacetophenone, 2- Examples thereof include hydroxy-2-methyl-propiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, α, α-dimethoxy-α-phenylacetone and the like. In addition, you may use a some compound together as a photoinitiator. The content of the photopolymerization initiator may be about 0.01 to 10 parts by weight, preferably about 0.5 to 8 parts by weight with respect to 100 parts by weight of the component (A). When the content of the photopolymerization initiator is less than 0.01 parts by weight with respect to 100 parts by weight of the component (A), curing is insufficient, stickiness of the coating film, and ink bleeding occurs during printing. Image quality may deteriorate. Moreover, when it exceeds 10 weight part, yellowing and coloring of a coating film may be seen.

  As an ultraviolet ray source for irradiating the coating film, an ordinary source such as a metal halide lamp or a mercury lamp may be used.

  ADVANTAGE OF THE INVENTION According to this invention, the composition for ink receiving layer formation which can form the ink receiving layer excellent in image preservability, such as quick-drying property, image sharpness, and water resistance can be provided. The component (B) contained in the ink receiving layer forming composition of the present invention contains an egg white component. Since the egg white component is a water-soluble protein, it can be used as a filler excellent in water-based ink absorbability. Furthermore, proteins have many functional groups such as amino groups in their molecules. Since these have binding property or affinity for acidic dyes, they have dye fixing properties. Thus, since the component (B) has an appropriate water absorption and dye fixing property, it can form an ink receiving layer that can form an ink receiving layer excellent in image storability such as quick drying, image sharpness, and water resistance. A composition can be provided.

  The substrate to be printed of the present invention comprises a supporting substrate and an ink receiving layer provided on the supporting substrate. The ink receiving layer is a layer formed using the above-described composition for forming an ink receiving layer.

  Examples of the supporting base material include paper and plastic base materials such as polyester resin, polycarbonate resin, acrylic resin, and cellulose resin.

  The ink receiving layer is formed by applying the ink receiving layer forming composition to a supporting substrate by any printing method such as screen printing, gravure printing, flexographic printing or any other coating method such as spin coating, dip coating, bar coating or roll coating. After coating, it is performed by curing by irradiation with radiation. As the radiation for curing, an electron beam, ultraviolet light, visible light, or the like can be used. The thickness of the ink receiving layer thus formed is desirably 5 to 100 μm, more preferably about 10 to 30 μm.

  The substrate to be printed of the present invention has an ink receiving layer suitable for the ink jet system. As described above, since this ink receiving layer is excellent in image characteristics such as quick drying and image sharpness, according to the present invention, it is possible to provide a substrate to be printed that enables printing with excellent image characteristics. it can. In particular, when the supporting base material is an optical recording medium, optical recording in response to a request that a general user wants to print a high-quality image such as characters or photographs representing the recorded contents for the purpose of designing the label surface of the disc. A medium can be provided. When the substrate to be printed is an optical recording medium, the optical recording medium is a coating-type recording layer mainly composed of a dye on a disk-shaped substrate formed of various transparent thermoplastic resins such as polycarbonate resin. The reflective layer and the protective film are provided in this order, and an ink receiving layer made of a radiation cured product of the coating composition of the present invention is provided on the protective film.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.
(Reference Example 1 )

In Reference Example 1, dry egg white particles were used as the component (B). As the dried egg white particles, those obtained by pulverizing dried egg white K type manufactured by QP Corporation with a jet mill were used. The average particle diameter of the obtained dried egg white particles was 7 μm. The average particle size was measured with a laser diffraction particle size distribution analyzer SALD2000A (manufactured by Shimadzu Corporation) (the same applies to Reference Examples 2 , 3 and Example 1 ).

The composition for forming an ink receiving layer according to Reference Example 1 was obtained by mixing this component (B) and each compound in the proportions shown in Table 1 below and stirring with a stirrer.

Then, an application layer was formed on the 125 μm-thick biaxially stretched polyester film by the bar coating method using the ink receiving layer forming composition. Immediately thereafter, ultraviolet rays were irradiated using a metal halide lamp and cured to form an ink receiving layer having a film thickness of 21 μm.
(Reference Example 2 )

In Reference Example 2, the same dried egg white particles and Luminous (calcium carbonate: manufactured by Maruo Calcium Co., Ltd.) as used in Reference Example 1 were used as the component (B).

The ink receiving layer forming composition according to Reference Example 2 was obtained by mixing the compounds shown in Table 1 below and stirring with a stirrer.

Subsequently, an ink receiving layer was formed in the same manner as in Reference Example 1 using this ink receiving layer forming composition. The obtained ink receiving layer had a thickness of 20 μm.
(Reference Example 3 )

In Reference Example 3, a filler composed of an egg white component that has been subjected to a hydrophobic treatment was used as the component (B). First, 25 g of dried egg white used in Reference Example 1 was dissolved in 225 ml of water. Next, this was dripped at 1000 ml of acetone. Thereby, the generated precipitate was collected by filtration. Then, it was dried at 40 ° C. The average particle diameter of the obtained particles (hereinafter referred to as “re-precipitated egg white particles”) was 0.6 μm. The composition for forming an ink-receiving layer according to Reference Example 3 was obtained by mixing the obtained component (B) and each compound shown in Table 1 below and stirring with a stirrer.

Next, an ink receiving layer was formed in the same manner as in Reference Example 1 using this ink receiving layer forming composition. The obtained ink receiving layer had a thickness of 18 μm.
(Example 1)

In Example 1 , silica gel, which is an inorganic filler, was coated with an egg white component as component (B). The component (B) was adjusted as follows. First, 25 g of dried egg white was dissolved in 225 ml of water. Next, 25 g of Silicia 350 (silica: manufactured by Fuji Silysia Chemical Co., Ltd.) was added and stirred. Thereafter, water was distilled off by filtration, and the recovered filtrate was heated and dried at 40 ° C. to obtain Silicia 350 whose surface was coated with an egg white component (hereinafter referred to as “egg white coating particles”). . The average particle diameter of the obtained particles was 2.4 μm. The composition for forming an ink receiving layer according to Example 1 was obtained by mixing the obtained component (B) and each compound shown in Table 1 below and stirring the mixture with a stirrer.

Next, an ink receiving layer was formed in the same manner as in Reference Example 1 using the ink receiving layer forming composition. The obtained ink receiving layer had a thickness of 20 μm.

[Comparative Examples 1-3]
In Comparative Examples 1-3, each compound was mix | blended in the weight ratio shown in following Table 1, this was stirred with the stirrer, and the composition for ink receiving layer formation concerning Comparative Examples 1-3 was obtained.

Next, an ink receiving layer was formed in the same manner as in Reference Example 1 using the ink receiving layer forming compositions according to Comparative Examples 1 to 3. The thicknesses of the obtained ink receiving layers were 20 μm in Comparative Example 1, 22 μm in Comparative Example 2, and 20 μm in Comparative Example 3.

(Evaluation)
Printing is performed on the ink receiving layers obtained in Example 1, Reference Examples 1 to 3 and Comparative Examples 1 to 3 using an inkjet printer PM-G700 (manufactured by Seiko Epson Corporation), and the following evaluation method is performed. The ink drying property, image sharpness, and water resistance were evaluated according to the above. The results are shown in Table 1.

Ink drying property: Paper was pressed against the printing surface of an ink jet printer, and the time until the ink was not transferred to the paper was measured and judged according to the following criteria.
○: Drying time is within 30 seconds.
Δ: Drying time from 30 seconds to 2 minutes.
X: Drying time is 2 minutes or more.

Image clarity: The image printed surface was observed visually and using an optical microscope (magnification: 100 times), and judged according to the following criteria.
○: The image is clear and clear.
Δ: Some blur is observed in the image.
X: The image is smudged severely or repels ink.

Water resistance (resistance to deterioration of image quality over time); after storage for 24 hours at 60 ° C. and 90%, image changes are observed visually and using an optical microscope (magnification: 100 times), and judged according to the following criteria did.
○: The change before and after storage at high temperature and high humidity is small, and the image definition is maintained.
Δ: Color tone change and bleeding are observed in the image.
X: The ink flows and the image is noticeably blurred.

As is apparent from the results shown in Table 1, the ink of Example 1 can form an ink receiving layer excellent in drying property, water resistance, and print quality.

  As described above, according to the composition for forming an ink receiving layer of the present invention, an ink receiving layer excellent in ink drying property, image sharpness, and water resistance can be formed on the surface of a substrate to be printed. .

Claims (10)

(A) a monomer component containing a monofunctional monomer;
(B) a filler containing an egg white component;
Only including,
The component (B) is a composition for forming an ink receiving layer , wherein the surface of inorganic particles or organic particles is covered with an egg white component . In claim 1,
The component (A) is a composition for forming an ink receiving layer, further comprising a bifunctional or higher monomer. In claim 1 or 2 ,
The composition for forming an ink receiving layer, wherein the component (B) has an average particle size of 0.01 to 30 μm. In any of claims 1 to 3 ,
The composition for forming an ink receiving layer, wherein the content of the component (B) is 5 to 200 parts by weight with respect to 100 parts by weight of the component (A). In any of claims 1 to 4 ,
Furthermore, the composition for ink receiving layer formation containing a polymerization initiator and content of this polymerization initiator is 0.01-10 weight part with respect to 100 weight part of said (A) component. In any of claims 1 to 5 ,
A composition for ink receiving formation which is cured by radiation. A support substrate;
An ink receiving layer provided on the support substrate and formed using the ink receiving layer forming composition according to any one of claims 1 to 6 . In claim 7 ,
The ink-receiving layer, said coating is formed on the supporting substrate, in which the coating film was cured by radiation, the printing substrate. In claim 7 or 8 ,
A substrate to be printed on which printing is performed by an inkjet method. In any of claims 7 to 9 ,
The substrate to be printed is a substrate to be printed, which is an optical recording medium on which at least one of writing and reading is optically performed.