JP2002019264A - Transparent coating material for pigment ink jet ink and recording material for pigment ink jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink receiving layer on a base material without using a primer because of excellent adhesiveness to a base material such as a metal, and excellent adhesiveness to a pigment ink. It has good printability even if it does not have a porous structure, and has a transparent coating material for pigment ink-jet ink having excellent water resistance and rub resistance by heating and drying after printing, and an ink receiving layer comprising the same. Provided is a recording material for pigment ink jet. A transparent coating material for a pigment ink-jet ink containing an acrylic polymer containing at least one hydrolyzable silyl group and / or silanol group in a molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention has excellent adhesiveness to a substrate such as a metal, so that an ink receiving layer can be formed on a substrate without using a primer, and the adhesiveness to a pigment ink can be improved. Because it is excellent, it has good printability even if it does not have a porous structure, and after printing a pigment ink on the ink receiving layer, it is heated and dried to have water resistance and abrasion resistance. The present invention relates to a transparent ink-jet coating material and a pigment ink-jet recording material using the same.

[0002]

2. Description of the Related Art Ink jet recording is a method in which ink is ejected from nozzles and adheres to a recording medium to perform recording. In recent years, with the spread of electronic still cameras and computers, the technology for recording those images on paper or the like has rapidly developed.However, in particular, the inkjet method is easy to use in full color and the printing noise is low. It is rapidly developing in recent years.

[0003] As the ink of the ink jet system, a water-based ink is generally used because a solvent-type ink dries quickly and clogs the nozzles, and a solvent-type ink has a problem in safety to a human body.

A water-based ink used in an ink-jet system is an ink in which a pigment and / or a dye are used as a colorant and a dispersant is water-based. Pigment inks have been used for signboards and the like as materials most suitable for outdoor use because they have better weather resistance than dye inks.

However, pigment ink differs from dye ink in that a pigment component remains on the surface of the ink receiving layer. Therefore, when a pigment ink is used, a porous structure for trapping the pigment is required on the surface of the receiving layer. And

When the receiving layer is white, pigments can be trapped by mixing a porous material such as silica or calcium carbonate in the receiving layer. However, when the receiving layer is transparent, Porous materials that can be used are
It was only alumina hydrate. However, the receiving layer obtained when this alumina material is used has a problem that the friction resistance in water is weak and the ink is peeled off.

[0007]

SUMMARY OF THE INVENTION In view of the above situation, the present invention has excellent adhesiveness to a substrate such as a metal, so that an ink receiving layer can be formed on a substrate without using a primer. Transparent coating material for pigment ink-jet inks that has excellent adhesion to pigment inks and therefore has good printability even if it does not have a porous structure, and has excellent water resistance and friction resistance when heated and dried after printing. And a pigment ink-jet recording material having an ink-receiving layer composed of the same.

[0008]

The present invention is a transparent coating material for a pigment ink jet ink containing an acrylic polymer containing at least one hydrolyzable silyl group and / or silanol group in a molecule. Hereinafter, the present invention will be described in detail.

The transparent coating material for a pigment ink-jet ink of the present invention (hereinafter also referred to as a transparent coating material) comprises an acrylic polymer containing at least one hydrolyzable silyl group and / or silanol group in a molecule. It contains.

[0010] The transparent coating material of the present invention contains an acrylic polymer having a hydrolyzable silyl group and / or a silanol group having excellent adhesiveness, so that it can be used for a pigment ink without having a porous structure. Express good adhesiveness,
In addition, even if a primer is not used, good adhesiveness to a base material such as a metal is exhibited.

The acrylic polymer is obtained by polymerizing a non-functional acrylic monomer and a hydroxyl group-containing acrylic monomer. Examples of the non-functional acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth)
Examples include non-functional acrylates such as acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and benzyl (meth) acrylate.

Examples of the above-mentioned hydroxyl group-containing acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
Hydroxyalkyl (meth) acrylates such as -hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate; 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, 6-
Hydroxyl-containing vinyl ethers such as hydroxyhexyl vinyl ether; 2-hydroxyethoxyallyl ether,
Allyl ethers containing a hydroxyl group such as 4-hydroxybutoxy allyl ether; adducts of these hydroxyl-containing monomers with ε-caprolactone;

When polymerizing the above acrylic polymer,
A crosslinking component may be added. Examples of the crosslinking component include a hydrophobic compound such as divinylbenzene; and a hydrophilic compound such as ethylene glycol dimethacrylate and methylenebisacrylamide.

By reacting the acrylic polymer with a vinyl monomer having a hydrolyzable silyl group,
A hydrolyzable silyl group and / or silanol group can be added to the acrylic polymer. Examples of the vinyl monomer having a hydrolyzable silyl group include, for example, γ
-(Meth) acryloxypropyltrimethoxysilane,
γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryloyloxypropyltriisopropenyloxy Silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl (tris-β-methoxyethoxy) silane, vinyltriacetoxysilane, vinyltrichlorosilane, N-β- (N-
Vinylbenzylaminoethyl) -γ-aminos.

The content of the acrylic polymer is preferably 50% by weight or more in the transparent coating material of the present invention. If the amount is less than 50% by weight, the resulting transparent coating material may have reduced adhesion to the substrate and the pigment ink. More preferably, it is 80% by weight or more.

The transparent coating material of the present invention preferably contains inorganic fine particles and has a light transmittance of 70% or more. Since the inorganic fine particles assist or promote water absorption, they act to improve the drying property and fixing property of the pigment ink in the obtained transparent coating material. Examples of the inorganic fine particles include silica such as wet silica and dry silica, calcium carbonate, and alumina. These may be used alone or in combination of two or more.
The amount of the inorganic fine particles is not particularly limited as long as the light transmittance of the obtained transparent coating material is 70% or more. In the transparent coating material of the present invention, if the light transmittance is less than 70%, it becomes difficult to determine the pattern of a base (substrate) and the like, so that it is difficult to use the transparent coating material.

The transparent coating material of the present invention preferably contains a cationic component. In addition, in this specification, the said cationic component means the compound which has a cationic group. In general, since the ink shows anionic property, the fixability of the ink to the ink receiving layer is improved by including the cationic component in the transparent coating material. The cationic component is not particularly limited, and includes, for example, an amine-based material,
Polyallylamine and the like can be mentioned. These may be used alone or in combination of two or more. The amount of the cationic component is not particularly limited as long as the light transmittance is in the range of 70% or more.

The method for producing the transparent coating material of the present invention is not particularly restricted but includes, for example, acrylic polymers, inorganic fine particles containing at least one hydrolyzable silyl group and / or silanol group in the molecule. The transparent coating material of the present invention can be obtained by blending a cation component with a known device used for dispersion and blending, for example, a sand mill or a homogenizer.

Since the transparent coating material of the present invention has the above-mentioned constitution, it can be well adhered to a substrate without using a primer, and an ink receiving layer in close contact with the substrate can be obtained. The transparent coating material of the present invention also has excellent adhesiveness with the pigment ink, and thus has good printability with the pigment ink.

By coating the transparent coating material of the present invention on a substrate to form an ink receiving layer, a recording material for pigment ink jet can be manufactured. A pigment ink-jet recording material (hereinafter, also referred to as a recording material) having an ink receiving layer formed by applying the transparent coating material of the present invention on a substrate is also one of the present invention.

The substrate used for the recording material of the present invention is not particularly limited, and examples thereof include those made of metal and resin. The resin is not particularly limited, and examples thereof include a thermoplastic resin and a thermosetting resin. The metal is not particularly limited, and examples thereof include iron and aluminum. When an easily oxidizable metal such as iron is used as the base material, plating is preferably performed for rust prevention. These may be used alone or in combination of two or more. Further, a composite composed of the above resin and metal can also be used as the above substrate.

The ink receiving layer is formed by applying the transparent coating material of the present invention to the surface of the substrate.
The method for applying the transparent coating material of the present invention is not particularly limited, and a known method can be used. For example, a gravure coating method, a gravure reverse coating method, a roll coating method, a wire bar coating method, a blade coating method , Knife coating method, air knife coating method, comma coating method,
Slot die coating, dip coating, spray coating and the like can be mentioned. When providing an ink receiving layer using such a method, an ink receiving layer having the same composition may be formed by overlapping a plurality of times, or an ink receiving layer having a different composition may be formed by overlapping a plurality of times. Is also good.

When applying the transparent coating material of the present invention to the surface of a substrate, it is preferable to apply the transparent coating material of the present invention directly to the substrate without using a primer. Since the transparent coating material of the present invention has excellent adhesion to a substrate as described above, an ink-receiving layer in close contact with the substrate can be formed without using a primer.

The thickness of the ink receiving layer is preferably 20 to 100 μm as a thickness when dried. 20μ dry thickness
If it is less than m, it may be difficult to reliably absorb the ink in the ink receiving layer, so that a good image may not be formed by the inkjet method. 10
If it exceeds 0 μm, the drying speed differs between the surface of the coated ink receiving layer and the inside thereof, and cracks may be generated on the surface. More preferably, the thickness when dried is 30 to
80 μm.

When printing on the recording material of the present invention with a pigment ink, the ink receiving layer is dried at room temperature to form a film, and then the unreacted hydrolyzable silyl group having adhesive properties and / or
Alternatively, the pigment ink is attached in a state where the silanol group exists. By attaching the pigment ink in a state in which unreacted hydrolyzable silyl groups and / or silanol groups are present, it is possible to use one liquid even without a porous structure as in a conventional ink receiving layer. Since the adhesiveness with the pigment ink is good, it is possible to print satisfactorily.

The ink receiving layer obtained by curing the transparent coating material of the present invention by heating and condensing the hydrolyzable silyl group and / or silanol group completely to eliminate the water-resistant and water-resistant ink. Although it has excellent frictional properties, after it is completely cured, the adhesion between the ink receiving layer and the pigment ink and the permeability of the pigment ink into the ink receiving layer deteriorate. Therefore, when printing on the recording material of the present invention, after applying the transparent coating material of the present invention on a substrate, printing is performed with a pigment ink until the ink receiving layer is completely cured. .

After printing on the recording material of the present invention with a pigment ink, for example, by heating to 100 to 150 ° C. and drying / curing, the hydrolyzable silyl groups and / or silanol groups in the ink receiving layer are reduced. By condensing, the recording material of the present invention can be imparted with water resistance and friction resistance.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 A reaction vessel equipped with a stirrer, a thermometer, a condenser, a dropping funnel and a nitrogen gas inlet was placed in a reaction vessel.
1500 parts by weight of deionized water was added, 40 parts by weight of Emulgen 950 (manufactured by Kao Corporation) was added as an emulsifier, and the temperature was raised to 80 ° C. while blowing nitrogen with stirring to dissolve the emulsifier. Azobisamidinopropane 2
3 parts by weight of hydrochloride are added, followed by 400 parts by weight of tert-butyl (meth) acrylate, 350 parts by weight of n-propyl (meth) acrylate, 100 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of methacrylic acid, γ
1 part by weight of methacryloxypropyltrimethoxysilane, 45 parts by weight of 2-hydroxyethyl methacrylate,
The monomer mixture composed of 1 part by weight of n-dodecyl mercaptan was added dropwise over 3 hours to carry out polymerization. After the completion of the dropwise addition, the mixture was stirred at the same temperature for 2 hours. Then, after cooling the contents of the reaction vessel, the pH is adjusted with ammonia water so as to exceed 8, and the solid content concentration is adjusted with deionized water to 40.0%. Then, an acrylic polymer having a hydrolyzable silyl group was obtained. Next, a transparent coating material comprising 100% by weight of the obtained acrylic polymer having a hydrolyzable silyl group was obtained.

A sample obtained so as to have a thickness of 40 μm after drying was coated on an aluminum plate to form an ink receiving layer, and then dried at room temperature for 8 hours to obtain a recording material. Characters of each color (yellow, magenta, cyan, carbon black) were printed thereon by a pigment ink jet printer, and then dried and cured at 120 ° C. for 20 minutes to obtain an evaluation sample. The light transmittance of the transparent coating material produced as described above was measured by the method shown in (1) below, and was 95%. The obtained ink-jet recording material was evaluated by the following method (2), and the results are shown in Table 1.

[Evaluation Method] (1) Light Transmittance The transparent coating material was applied to a glass plate and measured with a luminance meter. (2) Evaluation of Inkjet Image Using a commercially available pigment ink jet printer (for advertising, manufactured by Mimaki), visual printing evaluation, water resistance test, and rub resistance test were performed. Print evaluation: Characters were printed in each color (yellow, magenta, cyan, carbon black) with pigment ink, and visually determined for ink bleed.

Water resistance test: The evaluation sample was left in water for 3 hours, visually checked for ink flow, and evaluated as follows. ×: Ink flows ○: Ink does not flow

Abrasion resistance test: The evaluation sample was left in water for 3 hours, rubbed with a finger in water, visually checked for ink flow, and evaluated as follows. ×: ink peels off ○: ink does not peel off

Example 2 A transparent coating material was produced in the same manner as in Example 1 except that fumed silica was added in the composition shown below. (Composition of transparent coating material) 97% by weight of acrylic polymer having hydrolyzable silyl group of Example 1 Dry silica: 300CF (manufactured by Nippon Aerosil Co., Ltd.) 3% by weight

The light transmittance of the obtained transparent coating material was measured in the same manner as in Example 1, and it was 70%. An evaluation sample was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 A transparent coating material was prepared in the same manner as in Example 1 except that the cationic component was added in the following composition. (Composition of transparent coating material) Acrylic polymer having a hydrolyzable silyl group of Example 1 90% by weight Cationic component: PAA-D11-HCL (manufactured by Nitto Boseki) 10% by weight

The light transmittance of the obtained transparent coating material was measured in the same manner as in Example 1, and it was 90%. An evaluation sample was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 Preparation of an acrylic polymer was carried out without adding γ-methacryloxypropyltrimethoxysilane, and an acrylic polymer containing no hydrolyzable silyl group was polymerized. A transparent coating material was produced in the same manner as in Example 1 except that the transparent coating material was used. An evaluation sample was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2) Evaluation was performed in the same manner as in Example 1 using genuine OHP paper for a Seiko Epson printer (trade name: pictorico, blended alumina fine particles, porous structure) as a recording material for ink jet. The results are shown in Table 1.

(Comparative Example 3) After forming the ink receiving layer, 120
An evaluation sample was prepared and evaluated in the same manner as in Example 1 except that the ink receiving layer was dried and cured by heating at 20 ° C. for 20 minutes. The results are shown in Table 1.

[0041]

[Table 1]

From Table 1, it can be seen that the recording materials for ink jets manufactured in Examples 1 to 3 have good printability.
By heating and drying the ink receiving layer after printing, the ink receiving layer was excellent in water resistance and abrasion resistance in water. Since the transparent coating material produced in Comparative Example 1 did not contain a hydrolyzable silyl group, the obtained inkjet recording material was:
Poor water resistance and abrasion resistance in water. Comparative Example 2
The ink-jet recording material having a porous structure of the above was inferior in abrasion resistance in water. The ink-jet recording material of Comparative Example 3 was printed after heating and curing the ink receiving layer, and thus had poor printability.

[0043]

As described above, the transparent coating material for pigment ink jet ink of the present invention has the above-mentioned constitution, and therefore, it is possible to form an ink-receiving layer in close contact with a substrate without using a primer. In addition, the pigment ink-jet recording material of the present invention has excellent adhesiveness and good printability with the pigment ink because the ink receiving layer is formed by applying the transparent coating material for the pigment ink-jet ink of the present invention. It is. Further, the pigment ink-jet recording material of the present invention,
After printing, by heating and drying and curing, the film has excellent water resistance and friction resistance.

Claims (4)

[Claims] 1. A transparent coating material for pigment ink-jet ink, comprising an acrylic polymer containing at least one hydrolyzable silyl group and / or silanol group in the molecule. 2. The composition contains inorganic fine particles and has a light transmittance of 70%.
The transparent coating material for a pigment ink-jet ink according to claim 1, wherein: 3. The transparent coating material for a pigment ink-jet ink according to claim 1, which contains a cationic component. 4. A pigment ink jet recording material comprising an ink receiving layer formed by applying the transparent coating material for a pigment ink jet ink according to claim 1, on a base material.