JPH09323476A - Cast coated paper for inkjet recording - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] Ink jet recording (printing) while maintaining high surface smoothness and high gloss originally possessed by cast coated paper.
Provide a cast coated paper having excellent suitability. SOLUTION: An undercoat coating layer containing a pigment and an adhesive is provided on a base paper, and a cast coating solution containing a polymer resin and a polyether cation-based surfactant is further coated to form a coating layer for casting. A cast coated paper for ink jet recording, which is formed by pressing and coating the cast coating layer on a heated mirror surface drum and drying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cast coated paper for ink jet recording, and more particularly to a cast coated paper having an excellent white paper surface gloss and excellent ink jet recording (printing) suitability.

[0002]

2. Description of the Related Art In recent years, recording by an ink jet printer has been used in various fields because of its low noise, high speed recording, and easy multicoloring. As the ink jet recording paper, high-quality paper designed so as to have high ink absorbability, coated paper having a surface coated with a porous pigment, or the like is applied. By the way, all of these papers are mainly so-called matte ink jet recording papers having low surface gloss.

However, recently, with the expansion of applications such as speeding up of ink jet recording, high definition of recorded images, and full-colorization, an ink jet recording sheet having a high surface gloss and an excellent appearance has been demanded. Generally, for paper with high surface gloss, apply a plate-like pigment on the surface,
Further, it is obtained by copying the mirror surface of the coated paper having a high gloss, which has been subjected to a calendering treatment, or a wet coating layer, by pressing and drying it on a heating drum surface having a mirror surface, if necessary. Cast coated paper and the like are known.

This cast coated paper has high surface gloss and more excellent surface smoothness as compared with a normal coated paper which has been subjected to a super calender finish, and an excellent printing effect can be obtained. However, when used as an ink jet recording sheet, it has various difficulties.

That is, in general, cast coated paper obtains high gloss by film-forming substances such as adhesives in the pigment composition constituting the coating layer, which is transferred from the mirror surface of the cast coater. When used as an inkjet recording paper, there is a problem that these film-forming substances prevent ink absorption. Furthermore, the pigments and binders used in general cast paints have nonionic or anionic properties and cannot fix the dyes of ink jet inks, resulting in poor water resistance of printed images and insufficient print density. I have a problem.

Generally, in ink jet recording paper, it has been attempted to improve the water resistance and print density of a printed image by using a cationic resin in the coating layer. However, it is difficult to use as a cast paint because of its poor releasability and poor compatibility with other anionic auxiliaries such as a releasing agent and a thickener. As described above, it is extremely difficult to satisfy both the surface gloss of the cast coated paper and the suitability for inkjet recording (printing) at the same time.

[0007]

DISCLOSURE OF THE INVENTION It is an object of the present inventor to provide a cast coated paper which maintains the high surface smoothness and high gloss originally possessed by the cast coated paper and is excellent in ink jet recording (printing) suitability. Especially. The present invention shows excellent ink jet recording and recording suitability, maintains the original high gloss of cast coated paper, and has excellent inkjet (printing) recording suitability that cannot be obtained by conventional cast coated paper. Provide coated paper.

[0008]

The present invention includes the following aspects. [1] An undercoat coating layer containing a pigment and an adhesive is provided on the base paper, and a cast coating solution containing a polymer resin and a polyether cation-based surfactant represented by the following formula (1) is applied. To form a coating layer for casting, and the coating layer for casting is brought into pressure contact with a heated mirror surface drum and dried to finish. (N in the formula represents a natural number, and R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a lower alkyl group.)

[2] The coating layer for casting contains 0.1 to 15 parts by weight of the polyether cation-based surfactant represented by the formula (1) with respect to 100 parts by weight of the polymer resin.
The cast coated paper for ink-jet recording according to [1], which comprises 1 part by weight.

[0010]

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(N in the formula is a natural number, and R ₁ , R ₂ ,
R ₃ and R ₄ each represent a hydrogen atom or a lower alkyl group. [3] The cast coated paper for inkjet recording according to [1] or [2], wherein the polymer resin is a polymer resin having a glass transition point of 40 ° C. or higher obtained by polymerizing a monomer having an ethylenically unsaturated bond. .

[4] A base paper provided with an undercoating layer containing a pigment and an adhesive contains a polymer resin having a glass transition point of 40 ° C. or higher obtained by polymerizing a monomer having an ethylenically unsaturated bond. The coating liquid for coating is applied to form a coating layer for casting, and while the coating layer for casting is in a wet state, it is pressed against a heated mirror surface drum and dried to finish. In the paper, a cast coated paper for inkjet recording, characterized in that the coating layer for casting contains a polyether cationic surfactant represented by the above formula (1). (N in the formula represents a natural number, and R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a lower alkyl group.)

[5] The cast coated paper for inkjet recording according to any one of [1] to [5], wherein the lower alkyl group is a methyl group. [6] An undercoat coating layer containing a pigment and an adhesive is provided on the base paper, and a cast coating solution containing a polymer resin and the polyether cation-based surfactant represented by the above formula (1) is applied. To form a coating layer for casting, which is pressed by a heated mirror-finished drum while the coating layer for casting is in a wet state, and dried to obtain a wet cast method [1] to [5] The cast coated paper for inkjet recording described in any of the above. (In the formula, n represents a natural number, and R ₁ , R ₂ , R ₃ , and R ₄ each represent a hydrogen atom or a lower alkyl group.) Incidentally, the wet cast method provides particularly excellent gloss and recording suitability. .

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present inventors have
As a result of extensive studies on the coating composition for coating (coating layer), a specific resin having a specific glass transition point was applied on the base paper on which the undercoating coating layer containing a pigment and an adhesive as a main component was provided. The desired composition of the present invention is obtained by applying a coating solution containing a compound corresponding to the above formula (1) as a polyether cation surfactant in a casting coating liquid containing the main component, and subjecting it to cast finishing. The inventors have found that a cast coated paper for inkjet recording having an excellent surface glossiness and an excellent inkjet recording (printing) suitability can be obtained, and completed the present invention.

The polymer resin as the main component of the coating composition for casting may be a coating composition containing a polymer resin obtained by polymerizing a monomer having an ethylenically unsaturated bond. That is, in the present invention, a polymer resin obtained by polymerizing a monomer having an ethylenically unsaturated bond (hereinafter referred to as an ethylenic monomer) used as a main component of a coating composition for casting includes, for example, methyl acrylate and ethyl. Acrylate butyl acrylate, 2 ethylhexyl acrylate, lauryl acrylate, 2
-Alkyl groups such as hydroxyethyl acrylate and glycidyl acrylate having 1 to 18 carbon atoms, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and glycidyl methacrylate 1 to 18 methacrylic acid esters, styrene, α-methylstyrene, vinyltoluene, acrylonitrile, vinyl chloride, vinylidene chloride,
Vinyl acetate, vinyl propionate, acrylamide, N
A polymer obtained by polymerizing ethylenic monomers such as methylol acrylamide, ethylene and butadiene.

The polymer may be a copolymer in which two or more kinds of ethylenic monomers are used in combination, if necessary, and further, these polymers or a substituted derivative of the copolymer may be used. Incidentally, examples of the substituted derivative include a carboxyl group derivative and an alkali derivative thereof. Further, the above-mentioned ethylenic monomer is polymerized in the presence of colloidal silica to obtain Si-
It is also possible to use it in the form of a complex by OR (R: polymer component) bond.

As described above, the polymer resin obtained by polymerizing the above ethylenic monomer has a glass transition point of 40.
It is preferably at least ℃, more preferably 50-100
It is preferably in the range of ° C.

That is, in the conventional cast coated paper,
In order to obtain an excellent surface gloss, the resin content in the coating liquid was sufficiently formed into a film during the cast finish to obtain the cast gloss. However, such a method is not preferable because the porosity of the surface of the cast coated paper is reduced and, as a result, the absorption of ink during inkjet recording is reduced.
In the present invention, in order not to reduce the absorption of this ink,
Using a polymer resin having a high glass transition point, and in a mode where the polymer resin is cast-finished in a state where a film is not completely formed, the decrease in porosity of the cast coated paper surface is particularly small, Ink absorption does not decrease, and a cast coated surface having an excellent glossy surface can be obtained. On the other hand, when the glass transition point of the polymer resin is lower than 40 ° C., heat of the surface of the cast drum may cause film formation of the resin component, which may reduce the porosity of the surface of the cast coated paper and reduce the surface area. The gloss value is high, but the ink absorbency may decrease.

Next, the polyether cation type surfactant which is the most important element of the present invention will be described. As described above, the surfactant of the present invention is represented by the above chemical formula (1). In the formula (1), n represents a natural number, preferably 1 to 500, more preferably 5 to
60. Since this surfactant has a cationic property, the fixability of the inkjet ink can be enhanced, and the density and water resistance of the printed image can be improved. Further, unlike the cationic polymers conventionally used for ink jet, it has good compatibility with an anionic substance, and therefore can be used in combination with the above-mentioned casting resin. The polyether cation-based surfactant of the present invention is used in an amount of 0.1 to 100 parts by weight of the solid content of the polymer resin.
It is preferably added in the range of ˜15 parts by weight. By the way, when the amount is small, the water resistance of the image and the printing density tend to be lowered, while when the amount is large, the gloss tends to be lowered.

In the coating composition for casting, in order to adjust the whiteness, viscosity, fluidity and the like, pigments, dispersants and thickeners used in general coated paper for printing and ink jet paper are used. Various auxiliaries such as agents, defoaming agents, colorants, antistatic agents and preservatives are appropriately added.

Next, the pigment and the adhesive which are the main components of the undercoat layer will be described. That is, as the pigment, for example, kaolin, clay, calcined clay, amorphous silica, zinc oxide, aluminum oxide, aluminum hydroxide, calcium carbonate, satin white, aluminum silicate, smectite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, Zeolite, hydrotalcite,
Various publicly known pigments used in the general coated paper manufacturing field such as styrene-based plastic pigments, urea resin-based plastic pigments, and benzoguanamine-based plastic pigments can be used.

Among the above pigments, in terms of making the structure of the coating layer porous and excellent in ink absorption,
Pigments such as amorphous silica, aluminum oxide and smectite are particularly preferably used.

Next, as the adhesive, proteins such as casein, soybean protein, and synthetic protein, various starches such as starch and oxidized starch, polyvinyl alcohol, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, and styrene-butadiene copolymerization Conventionally commonly used for coated papers such as coalesce, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl polymer latex such as ethylene-vinyl acetate copolymer, etc. Known adhesives may be used alone or in combination. The amount of the adhesive compounded is 5 to 50% by weight, more preferably 10 to 30% by weight, based on the pigment.
Adjusted in the range of.

The undercoat layer contains polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine conventionally used for ink jet recording paper, or derivatives thereof, tertiary amino groups and quaternary ammonium groups. 1 to 30 parts by weight of a cationic resin such as acrylic resin or diacrylamine is added to 100 parts by weight of the pigment for the purpose of further improving the water resistance of the printed image.
More preferably, it can be used in the range of 5 to 20 parts by weight.

In addition, various auxiliaries such as a dispersant, a thickener, an antifoaming agent, a colorant, an antistatic agent and a preservative used in the production of general coated paper are appropriately added. Thus, the composition for the undercoat layer, which is composed of the above-mentioned materials, generally has a solid content of about 1 to 65% by weight, and a weight of about 20 square meters.
Dry weight of 2 to 50 g on base paper of about 400 g / m ²
/ M ² , more preferably about 5 to ²⁰ g / m ² by various publicly known coating devices such as a blade coater, an air knife coater, a roll coater, a brush coater, a chanplex coater, a bar coater and a gravure coater. Coated and dried. Further, if necessary, smoothing treatment such as super calendering and brushing can be performed after the undercoat coating layer is dried.

The base paper used as the base is not particularly limited, and acidic paper used for general coated paper, neutral paper, synthetic paper, porous film and the like are appropriately used. On the coated surface of the undercoat coated paper thus obtained, a cast coating liquid consisting of the specific polymer composition described above, a blade coater, an air knife coater, a roll coater, a brush coater, a Chanplex coater, a bar coater, Coating is performed by various known coating devices such as a gravure coater, and while the coating layer is in a wet state as described above, the heated mirror-finished drum is pressed and dried to be cast-finished. The coating amount of the cast coating liquid in this case is 0.2 to 30 g / m ² in terms of dry solid content,
It is preferably 1 to 10 g / m ² .

[0026]

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.
Unless otherwise specified, parts and% in the examples represent parts by weight and% by weight, respectively.

Example 1 90 parts of amorphous silica as pigment, 1 part of light calcium carbonate
0 parts, as an adhesive, 20 parts of polyvinyl alcohol,
Dicyandiamide resin as thione resin (trade name:
Neofix FY / manufactured by Nichika Chemical Co., Ltd.) 10 parts,
Add 0.5 parts of sodium polyphosphate as a dispersant
An undercoating coating liquid having a concentration of 18% was prepared. This undercoat
Coating liquid for rice, 100 g / m2^Two1 dry weight on base paper
2 g / m ^TwoPaint with an air knife coater
The coated and dried base paper was obtained.

On the other hand, as a cast coating liquid, glass transition
Styrene-2 methylhexyl acrylate with a point of 80 ° C
Composite of polymer and colloidal silica (Movinyl 805
0: manufactured by Hoechst Synthesis) 100 parts, polyether of the present invention
Cationic surfactant (Adeka Call CC- manufactured by Asahi Denka Co., Ltd.)
9, in the above formula (1), n = 9, R₁, R_Two, R_Three, R _Four
Each is a hydrogen atom or a methyl group) 10 parts, and a release agent
And the solid content concentration of 2 parts calcium stearate
A 30% casting coating liquid was prepared. This coating liquid on top
Coated on the undercoat base paper described above using a roll coater
Immediately afterwards, press contact with the mirror surface drum whose surface temperature is 80 ° C,
After drying, release and cast coating for inkjet recording
Got the paper. The coating amount at this time is 5 g / m in terms of solid content weight.
^TwoMet.

Example 2 In Example 1, the surfactant was a polyether cation type (Adeka Call CC-36 manufactured by Asahi Denka Co., Ltd., the above formula (1)).
Then, a cast coated paper for ink jet recording was obtained by the same method as in Example 1 except that n = 36, R ₁ , R ₂ , R ₃ and R ₄ were each 5 parts hydrogen atom or methyl group).

Example 3 In Example 1, the surfactant was a polyether cation type (Adeka Call CC-42 manufactured by Asahi Denka Co., Ltd., the above formula (1)).
Then, a cast coated paper for inkjet recording was obtained in the same manner as in Example 1 except that n = 42, R ₁ , R ₂ , R ₃ , and R ₄ were each 0.5 part). .

Example 4 In Example 1, a polyether cation-based surfactant (Adekacol CC-9 manufactured by Asahi Denka Co., Ltd., the above formula (1),
n = 9, R ₁ , R ₂ , R ₃ and R ₄ are each hydrogen atom or methyl group) and the cast coated paper for inkjet recording was prepared in the same manner as in Example 1 except that the addition amount was 0.05 parts. Obtained.

Example 5 A cast coated paper for ink jet recording was obtained in the same manner as in Example 1 except that 20 parts of the polyether cation-based surfactant (Adeka Call CC-9 manufactured by Asahi Denka Co., Ltd.) was used. .

Example 6 As a cast coating liquid, 100 parts of a composite of a styrene-methyl acrylate copolymer having a glass transition point of 70 ° C. and colloidal silica, a polyether cation type surfactant (Adeka Call CC-9 manufactured by Asahi Denka Co., Ltd.) 8 parts, 3 parts ammonium oleate as a release agent, 40% solids concentration
A coating liquid for casting was prepared. This coating liquid was used in Example 1.
The undercoat base paper obtained in 1. was coated with a roll coater, then immediately pressed against a heated mirror surface drum having a surface temperature of 65 ° C., dried, and released to obtain a cast coated paper for inkjet recording. The coating amount at this time is the solid content weight,
It was 6 g / m ² .

Example 7 70 parts of Al ₂ O ₃ as a pigment of an undercoating liquid, 30 parts of amorphous silica, 5 parts of oxidized starch as an adhesive, 15 parts of polyvinyl alcohol, and a polyethylene polyamine-based resin as a cationic resin ( Product name: Neofix RP-7
0 / Nippa Kagaku Kogyo Co., Ltd. 8 parts and 0.4 parts of sodium polyphosphate as a dispersant were added to prepare an undercoating coating liquid having a solid content concentration of 30%. This undercoat coating liquid
g / m ² of the base paper so that the dry weight becomes 9 g / m ² .
It was coated with a blade coater and dried to obtain an undercoat base paper.
The undercoat base paper was coated with the casting coating liquid used in Example 1 to obtain an inkjet recording cast coated paper in the same manner as in Example 1.

Comparative Example 1 An ink jet recording cast coated paper was obtained in the same manner as in Example 1 except that the polyether cation type surfactant was not added.

Comparative Example 2 Eight parts of polyethylene polyamine resin (trade name: Neofix RP-70 / Nikaka Chemical Co., Ltd.) was used as the cationic resin in place of the polyether cationic surfactant in Example 1. A cast coated paper for inkjet recording was obtained in the same manner as in Example 1 except that the addition was performed.

Comparative Example 3 In Example 1, a dicyandiamide resin (trade name: Neofix FY / Nikaka Chemical Industry Co., Ltd.) was used as a cationic resin instead of the polyether cationic surfactant.
A cast coated paper for ink jet recording was obtained by the same method as in Example 1 except that 10 parts of (produced) was added.

Comparative Example 4 A diallylamine- (meth) acrylamide copolymer (trade name: Sumirez Resin # 1001, manufactured by Sumitomo Chemical Co., Ltd.) as a cationic resin in place of the polyether cationic surfactant in Example 1 A cast coated paper for inkjet recording was obtained in the same manner as in Example 1 except that 10 parts of was added.

The results of white gloss, ink jet recording suitability and operability of the cast coated paper thus obtained are summarized in Table 1. The above evaluation was carried out by the following method. [White paper gloss] Measured according to JIS-P8142.

[Ink jet recording suitability] (Absorbability of ink for ink jet recording) Printing was performed with a color image jet IO-735X (ink jet recording apparatus) manufactured by Sharp Corporation, and the drying property of the ink was visually evaluated. . ⊚: No stain at all when touched with a finger immediately after printing. ◯: Slightly soiled when touched with a finger immediately after printing, but almost dry. Δ: The ink portion is slightly shiny immediately after printing, but there is no problem in practical use. X: Due to poor drying of the ink, the ink flows during printing and cannot be used practically.

(Printing Density of Inkjet Recording Ink After Recording) Printing was performed with Color Image Jet IO-735X manufactured by Sharp Corporation, and the density of the ink was visually evaluated. ◯: Print density is good. Δ: The print density is relatively light. X: The print density is too low to be practical.

[Stability of Cast Coating Liquid] ◯: Stable coating can be performed. X: Gelation occurs and coating is impossible.

[Printed image water resistance] Printing was performed with Color Image Jet IO-735X manufactured by Sharp Corporation, water droplets were applied to the printed portion, and ink bleeding and flow were visually evaluated. ◯: Good water resistance with no ink bleeding or flow in the printed area. Δ: Some bleeding is recognized on the printed part. Poor: Ink flow was found in the printed area, and the water resistance was relatively poor.

[0044]

[Table 1]

In Comparative Example 2, Comparative Example 3 and Comparative Example 4, the paint agglomerated and the fluidity was lost. Therefore, it could not be applied.

[0046]

As is clear from the results of Table 1, the cast coated paper of the present invention is excellent in surface gloss and ink jet recording suitability. Also, the stability of the paint is excellent, and stable quality can be obtained.

Claims (3)

[Claims] 1. An undercoat coating layer containing a pigment and an adhesive is provided on a base paper, and a cast coating liquid containing a polymer resin and a polyether cation-based surfactant represented by the following formula (1) is further provided. A cast coated paper for inkjet recording, which is formed by coating to form a coating layer for casting, pressing the coating layer on a heated mirror surface drum, and drying. (N in the formula represents a natural number, and R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a lower alkyl group.) 2. The coating layer for casting contains 0.1 to 15 parts by weight of the polyether cation-based surfactant represented by the formula (1) per 100 parts by weight of the polymer resin. Item 1. The cast coated paper for inkjet recording according to Item 1. 3. The cast coating for ink jet recording according to claim 1 or 2, wherein the polymer resin is a polymer resin having a glass transition point of 40 ° C. or higher obtained by polymerizing a monomer having an ethylenically unsaturated bond. paper.