JP5741476B2 - Inkjet paper - Google Patents

Description

  The present invention relates to an inkjet paper, and more particularly to an inkjet paper having excellent solid print portion uniformity and barcode printability even in full-color printing in a high-speed inkjet system.

In recent years, as a means for displaying image information and the like produced on a personal computer on paper, heat and pressure are used as a drive source, and liquid dye ink or pigment ink is ejected from the nozzle onto the paper to form an image with the ink. An ink jet recording system for printing and an electrophotographic recording system for printing by forming an image by transferring toner onto a sheet are used. Also, in the field of commercial printing, the inkjet recording method and electrophotographic recording method that are optimal for printing a small number of copies and variable information printing (variable printing) because digital information can be directly printed on media such as paper without making a plate. Has been introduced in the field of on-demand printing.
In particular, the ink jet system has been developed rapidly in recent years because of its low noise during recording, easy colorization, and high speed recording.

However, high-quality paper used for general printing is inferior in ink absorbability, so the printed ink does not dry on the paper surface and remains for a long time, which can contaminate the device and stain the image. poor.
In order to solve these problems, a low-size paper is used (see, for example, Patent Document 1), or an electrophotographic and ink-jet recording paper having an appropriate size and containing a filler such as calcium carbonate ( For example, see Patent Document 2). However, since the recording medium in the above proposal is recorded with water-based ink, if water or the like adheres to the recording image formed on the medium, the recording image is deteriorated due to poor water resistance. Has drawbacks.

  Therefore, a water-proofing agent that forms a lake with a dye such as a cationic polymer or a water-soluble metal salt is added after printing (see, for example, Patent Document 3), or a resin-type dye fixing agent or a quaternary ammonium salt is used as a basic compound. The thing (for example, refer patent document 4) etc. which apply | coated the dye sticking agent which is made is proposed. However, the dicyandiamide formaldehyde condensates shown in these proposals, and dye mordants composed of various cationic ink fixing agents such as polyamines and polyethyleneimines, when used in an amount capable of obtaining sufficient water resistance, In addition, there is a disadvantage that it causes a fading of the dye.

In order to solve these drawbacks, a quaternary ammonium salt having a specific structure (for example, see Patent Documents 5 to 7) or a polyalkylene polyamine dicyandiamide ammonium salt condensate is used (for example, see Patent Document 8). Etc. have been proposed. In addition, with the widespread use of high-speed inkjet systems, proposals have been made to provide ink drying properties and water resistance in high-speed inkjet systems (see, for example, Patent Documents 9 to 12). However, the recording sheet proposed above is inferior in water resistance depending on the color of the ink in full-color printing in a high-speed ink jet system, and the printed part is not clear enough when the printed material is splashed with water or immersed in water. Therefore, it was not satisfactory as a full-color printing paper.
Further, as in the present invention, it has been proposed to use aluminum sulfate (see, for example, Patent Documents 13 to 14), but the barcode printability was not sufficient.
Furthermore, it has been proposed to use an emulsion-type styrene-acrylic copolymer containing aluminum sulfate (see, for example, Patent Document 15), but the uniformity of the solid print area was not sufficient.

JP 52-53012 A JP-A-6-8617 JP-A-55-150396 JP-A-60-161188 Japanese Patent Laid-Open No. 61-293886 JP-A-62-238783 JP-A-1-9776 Japanese Patent Publication No. 2-35675 Japanese Patent Laid-Open No. 9-202042 JP 2000-265394 A Japanese Patent Laid-Open No. 2003-326831 JP 2000-247016 A Japanese Patent No. 3832203 Japanese Patent Laid-Open No. 11-334199 JP 2010-196237 A

  An object of the present invention is to provide an inkjet paper that has sufficient solid print portion uniformity even in full-color printing in a high-speed inkjet system, and has excellent barcode printability and scratch resistance.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that this can be achieved by adopting the following configuration, and have reached the present invention.

(1) In an ink jet paper coated with a surface sizing agent containing aluminum sulfate, starch and a surface sizing agent on both sides of the base paper, the surface sizing agent is a solution-type styrene polymer. Or an inkjet paper characterized by being a solution-type styrene-acrylic copolymer.
(2) 10-100 parts by mass of aluminum sulfate, 40-90 parts by weight of starch, and 0.1-2 parts by mass of the surface sizing agent with respect to 100 parts by mass of the surface size press treating agent. The inkjet paper according to claim 1, wherein

  The ink jet paper according to the present invention is an ink jet paper that has sufficient uniformity of a solid print portion image and bar code printability even in full-color printing in a high-speed ink jet system, and an excellent print image can be obtained.

<Surface treatment agent>
The surface size press treating agent used in the present invention contains aluminum sulfate and starch and a solution-type styrene polymer or a solution-type styrene-acrylic copolymer as a surface sizing agent.

  10-60 mass parts is preferable with respect to 100 parts of surface size press total mass parts, and, as for the compounding quantity of the aluminum sulfate used by this invention, More preferably, it adjusts in the range of 20-40 mass parts. When the amount of aluminum sulfate is less than 10 parts by mass, the barcode printing suitability in inkjet printing and the water resistance of the printing unit are likely to decrease. When the amount exceeds 60 parts by mass, the amount of the water-soluble polymer is relatively decreased, and the surface strength is lowered.

In addition to aluminum sulfate, the surface treatment agent may contain a cationic resin or a metal salt other than aluminum sulfate as a water-resistant agent. Examples of the cationic resin include (1) alkylamine-epichlorohydrin copolymer, (2) acrylic polymer having secondary amino group, tertiary amino group and quaternary ammonium group, (3) polyvinylamine. , Polyvinylamidines, 5-membered ring amidines, (4) dicyandiamide cationic resin typified by dicyandiamide-formalin copolymer, (5) polyamine cation resin typified by dicyandiamide-polyethyleneamine copolymer, (6) polyalkylene polyamines or derivatives thereof, such as polyethylene polyamine or polypropylene polyamine, (7) diallyldimethylammonium -SO ₂ copolymer, (8) diallylamine salt -SO ₂ copolymer, (9) diallyl dimethyl ammonium chloride polymer, (10) Polymer of allylamine salt (11) Homopolymer or copolymer of vinylbenzyltriallylammonium salt, (12) Dialkylaminoethyl (meth) acrylate quaternary salt copolymer, (13) Acrylamide-diallylamine salt copolymer, (14) Poly Examples include commercially available aluminum salts such as aluminum chloride and polyaluminum acetate, and examples of metal salts other than aluminum sulfate include magnesium sulfate, zinc sulfate, calcium formate, calcium acetate, and calcium nitrate.

  Examples of the starch used in the present invention include cationized starch, raw starch, oxidized starch, etherified starch, and esterified starch. These starches have good compatibility with solution-type styrene polymers and solution-type styrene-acrylic copolymers, and after applying a size press treatment agent, solution-type styrene polymers and solution-type styrene- The acrylic copolymer is preferably distributed uniformly and the uniformity of the printed surface is improved.

  As for the compounding quantity of starch, 40-90 mass parts is preferable with respect to 100 parts of surface size press processing agent total mass parts, More preferably, it adjusts in the range of 60-80 mass parts. When the starch content is less than 40 parts by mass, the surface strength is lowered, and the smudge of the printed part is likely to occur. When the starch content exceeds 90 parts by mass, the ink drying property is deteriorated and the printed part is likely to be uneven.

In addition to starch, water-soluble celluloses such as carboxymethylcellulose, methylcellulose and hydroxyalkylcellulose, natural water-soluble polymer derivatives such as alginic acid, guar gum, xanthan gum and pullulan, cationized polyvinyl alcohol Polyvinyl alcohol, polyacrylamide, etc. may be used.

  The surface size press treating agent of the present invention contains a solution type styrene polymer or a solution type styrene-acrylic copolymer as a surface sizing agent. The blending amount of the surface sizing agent is preferably 0.1 to 2 parts by mass, more preferably 0.5 to 1 part by mass with respect to 100 parts by mass of the surface size press treating agent. When the surface sizing agent is less than 0.1 parts by mass, the barcode printability is lowered. When the surface sizing agent is more than 2 parts by mass, the ink drying property is liable to be lowered.

  The solution-type styrene polymer or solution-type styrene-acrylic copolymer is a water-dispersed so-called emulsion type, whereas the solution-type styrene polymer is dissolved in water via a solvent. It is contained in a state dissolved in the agent, and is uniformly applied when applied to the base paper, thereby improving the uniformity of the solid print portion. Commercially available products can use SS2702 and SS2700 manufactured by Seiko PMC.

  Further, various auxiliary agents as necessary, for example, surfactants, pH regulators, viscosity modifiers, softeners, gloss imparting agents, waxes, dispersants, flow modifiers, stabilizers, antistatic agents, crosslinking agents A sizing agent, a fluorescent brightening agent, a colorant, an ultraviolet absorber, an antifoaming agent, a water-proofing agent, a plasticizer, a lubricant, a preservative, and a fragrance are appropriately blended as necessary.

In the present invention, aluminum sulfate contained in the surface size press treating agent is 10 to 60 parts by weight, starch is 40 to 90 parts by weight, and the surface sizing agent is 0.1 to 100 parts by weight of the total size press treating agent. It is preferable to contain 2 parts by weight, and the coating amount is not particularly limited, but the amount of the base paper is adjusted so that the dry coating amount on both sides is in the range of 0.5 to 5.0 g / m ² . It is preferable to apply and dry on both surfaces, and more preferably in the range of 1.0 to 3.0 g / m ² . If the coating amount of the surface size press treating agent is less than 0.5 g / m ² , sufficient barcode printing suitability and water resistance cannot be obtained. On the other hand, if it exceeds 5.0 g / m ² , the ink drying property tends to decrease. Become.

<Base paper>
The base paper of the inkjet paper used in the present invention includes wood pulp such as chemical pulp (NBKP, LBKP, etc.), mechanical pulp (GP, CGP, RGP, PGW, TMP, etc.), deinked waste paper pulp (DIP, etc.) as raw material pulp. Are used alone or mixed in any ratio. Further, a paper filler such as white carbon, clay, amorphous silica, talc, titanium oxide, calcium carbonate is added during papermaking. Also, if necessary, publicly known papermaking chemicals such as internal sizing agents, fixing agents, paper strength enhancers, yield improvers, water resistance agents, ultraviolet absorbers, and the like are appropriately added to the publicly known paper machines. Paper. There are no particular limitations on the papermaking conditions of the base paper. As the paper machine, for example, a commercial paper machine such as a long paper machine, a gap former paper machine, a circular paper machine, or a short paper machine can be selected and used as appropriate according to the purpose. .
The base paper used for the inkjet paper of the present invention is not particularly limited, but generally, a base paper having a basis weight in the range of about 50 to 200 g / m ² is appropriately selected according to the purpose. used.

<Application of surface-size press treatment agent to base paper>
The apparatus for applying the surface size press treating agent to the paper base paper is not particularly limited. For example, a roll such as a two roll size press, a blade metalling size press, a rod metalling size press, or a gate roll coater. Coated, trailing, flexible, roll application, fountain application, short dwell type bevel type and bent type blade coater, rod blade coater, bar coater, air knife coater, curtain coater, spray coater, gravure coater, etc. A device is used as appropriate. In addition, as a method of drying the wet coating layer after apply | coating a surface treating agent composition, various systems, such as vapor | steam drying, gas heater drying, electric heater drying, infrared heater drying, are employable, for example.

  In the production of the inkjet paper of the present invention, after forming the coating layer of the surface size press treating agent composition, it may be subjected to a smoothing treatment in various calendar devices. As such a calendar device, a super calender is used. Commonly used calendar devices such as a soft calendar, a gloss calendar, a compact calendar, a mat super calendar, and a mat calendar can be used as appropriate. As the calender finishing conditions, the temperature of the rigid roll, the calender pressure, the number of nips, the roll speed, the paper moisture before the calender, and the like are appropriately selected according to the required quality. Furthermore, the calendar device includes an off type that is different from the coater and an on type that is integrated with the coater, but can be used in either case. The material of the calendar apparatus to be used is a roll which is mirror-finished with a metal or a hard chrome plating on the surface of a rigid roll. As the elastic roll, a roll obtained by molding a resin roll such as urethane resin, epoxy resin, polyamide resin, phenol resin, or polyacrylate resin, cotton, nylon, asbestos, aramid fiber, or the like is appropriately used. In addition, it is also possible to use a suitable combination of a water coating device, an electrostatic humidifier, a steam humidifier, and the like for humidity control and humidification of the coated paper after finishing with a calendar.

  The whiteness of the inkjet paper according to the present invention is not particularly limited. However, if it is 70% or more, preferably 75% or more, the printed surface is clear.

  The opacity of the inkjet paper according to the present invention is not particularly limited, but if it is 75% or more, preferably 80% or more, the opacity after printing can be maintained without the printing surface being transparent to the back surface of the printing surface.

  Hereinafter, the present invention will be described in more detail based on examples. In the examples, “part” means mass part, and “%” means mass%. The present invention is not limited to these examples.

<Adjustment of base material>
Eucalyptus, 100% EBK bleached LBKP using oak as raw material, beaten to 380 ml CSF, 10.0% light calcium carbonate as filler, alkenyl succinic anhydride (National Starch, Fibrin 81) as internal sizing agent A base paper having a basis weight of 81.4 g / m ² was prepared by 0.07% and a yield improver (Kyowa Sangyo Co., Ltd., Percoll 182) at a rate of 0.02% and using a long mesh multi-cylinder paper machine.

Example 1
On the base paper, a mixed coating solution of 30 parts of aluminum sulfate, 69.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 0.7 part of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) was added. The ink was coated and dried with a two-roll size press so that the both sides were 2.5 g / m ² to obtain an inkjet paper.

Example 2
On the above base paper, a mixed coating solution of 30 parts of aluminum sulfate, 69.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A), 0.7 part of a solution-type styrene polymer (Seiko PMC, SS2702) is mixed on both sides. The ink was applied and dried by a two-roll size press so as to obtain 0.5 g / m ² to obtain an ink jet paper.

Example 3
A mixed coating solution of 30 parts of aluminum sulfate, 69.3 parts of cationized starch (manufactured by Oji Cornstarch, Ace K) and 0.7 part of a solution-type styrene polymer (Seiko PMC, SS2702) is coated on both sides of the base paper. It was coated and dried with a two-roll size press so as to be 2.5 g / m ² to obtain an inkjet paper.

Example 4
A mixed coating solution of 15 parts of aluminum sulfate, 84.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 0.7 part of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) is placed on the above base paper. The ink was coated and dried with a two-roll size press so that the both sides were 2.5 g / m ² to obtain an inkjet paper.

Example 5
On the base paper, a mixed coating solution of 55 parts of aluminum sulfate, 44.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 0.7 part of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) was added. The ink was coated and dried with a two-roll size press so that the both sides were 2.5 g / m ² to obtain an inkjet paper.

Example 6
On the base paper, a mixed coating solution of 30 parts of aluminum sulfate, 69.8 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 0.2 part of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) was added. The ink was coated and dried with a two-roll size press so that the both sides were 2.5 g / m ² to obtain an inkjet paper.

Example 7
On the above base paper, a mixed coating solution of 30 parts of aluminum sulfate, 68.2 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 1.8 parts of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) The ink was coated and dried with a two-roll size press so that the both sides were 2.5 g / m ² to obtain an inkjet paper.

Example 8
On the base paper, a mixed coating solution of 30 parts of aluminum sulfate, 69.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 0.7 part of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) was added. The ink was coated and dried with a two-roll size press so that the both sides were 0.8 g / m ² to obtain an inkjet paper.

Example 9
On the base paper, a mixed coating solution of 30 parts of aluminum sulfate, 69.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 0.7 part of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) was added. The ink was coated and dried with a two-roll size press so as to obtain 4.0 g / m ^{2 on} both sides to obtain an inkjet paper.

Comparative Example 1
On the base paper, a mixed coating solution of 30 parts of aluminum sulfate, 69.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A), and 0.7 part of an emulsion type styrene-acrylic copolymer (Seiko PMC, SE2220) was added. The ink was coated and dried with a two-roll size press so that the both sides were 2.5 g / m ² to obtain an inkjet paper.

Comparative Example 2
A mixed coating solution of 30 parts of aluminum sulfate, 69.3 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A), and 0.7 part of an emulsion type styrene polymer (Seiko PMC, SE2202) is mixed on both sides of the base paper. The ink was applied and dried by a two-roll size press so as to obtain 0.5 g / m ² to obtain an ink jet paper.

Comparative Example 3
On the above base paper, a mixed coating solution of 30 parts of aluminum sulfate and 70 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) is coated and dried by a two-roll size press so that both sides have 2.5 g / m ^2. Inkjet paper was obtained.

Comparative Example 4
A mixed coating solution of 30 parts of aluminum sulfate, 69 parts of cationized polyvinyl alcohol (Electrochemical, PC5500) and 0.7 parts of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) is coated on both sides of the base paper. Was applied and dried with a two-roll size press so as to obtain 2.5 g / m ² to obtain an ink jet paper.

Comparative Example 5
On the above base paper, a mixed coating solution of 30 parts of sodium sulfate, 69 parts of oxidized starch (manufactured by Oji Cornstarch, Ace A) and 0.7 part of a solution-type styrene-acrylic copolymer (Seiko PMC, SS2700) is coated on both sides. The ink was coated with a two-roll size press so as to be 2.5 g / m ² and dried to obtain an ink jet paper.

The obtained inkjet paper was evaluated by the method shown below, and the obtained results are shown in Table 1.

<Inkjet printing suitability / Barcode printing suitability>
After printing the “UCC / EAN128 code” on the high-speed inkjet printing system MJP600 manufactured by Miyakoshi for the inkjet paper obtained in each example and comparative example,
The EAN128 bar code printed by inkjet was evaluated by scanning the bar code 10 times using a bar code verifier “Inspector D4000” (manufactured by RJS).
<Evaluation criteria>
5: Reads 10 times out of 10 scans of the barcode reader.
4: Reads 9 times out of 10 scans of the barcode reader.
3: 6 or more and less than 9 out of 10 scans of the barcode reader.
2: Level that can be read by passing a plurality of scanning lines through the barcode.
1: Level that cannot be read.
Those having an evaluation of 2 or less have a problem in practical use.

<Inkjet printing suitability / ink drying property>
After the “UCC / EAN128 code” was printed on Miyakoshi's high-speed inkjet printing system MJP600, the inkjet paper obtained in each example and comparative example was visually checked for ink transfer stains on the site where inkjet printing was performed. It was.
<Evaluation criteria>
5 (excellent) -1 (inferior)
Those having an evaluation of 2 or less have a problem in practical use.

<Inkjet printing suitability / water resistance>
After printing “color digital standard image data / N3” issued by the Japanese Standards Association with Miyakoshi high-speed ink jet printing system MJP600, the ink jet paper obtained in each example and comparative example was placed in tap water. After soaking for 2 seconds, it was naturally dried. Thereafter, the degree of bleeding of the printed image was visually evaluated.
<Evaluation criteria>
5 (excellent) -1 (inferior)
Those having an evaluation of 2 or less have a problem in practical use.

<Inkjet printing suitability / abrasion resistance>
The inkjet paper obtained in each of the examples and comparative examples was printed with Miyakoshi's high-speed inkjet printing system MJP600, and “color digital standard image data / N3” issued by the Japanese Standards Association was rubbed 10 times with a waste cloth. The degree of smearing on the printed part was visually evaluated.
<Evaluation criteria>
5 (excellent) -1 (inferior)
Those having an evaluation of 2 or less have a problem in practical use.

<Inkjet printing suitability / Solid print part uniformity>
After printing “color digital standard image data / N3” issued by the Japanese Standards Association with Miyakoshi high-speed inkjet printing system MJP600, the inkjet paper obtained in each example and comparative example is then printed in black, cyan, magenta, yellow solid The degree of all printing unevenness was visually evaluated.
<Evaluation criteria>
5 (excellent) -1 (inferior)
Those having an evaluation of 2 or less have a problem in practical use.

Table 1 shows the evaluation results of ink jet printing suitability in Examples 1 to 9 and Comparative Examples 1 to 5.

  As can be seen from Table 1, the inkjet paper of the present invention has sufficient solid print portion uniformity, barcode printability, ink drying properties, scratch resistance, and water resistance.

  The inkjet paper of the present invention has excellent water resistance, barcode printing suitability, ink drying property, scratch resistance, water resistance, and solid print uniformity even in inkjet printing, and is practically excellent. is there.

Claims (2)

In the ink jet paper that does not contain a pigment on both sides of the base paper and is coated with a surface size press treating agent containing aluminum sulfate, starch and a surface sizing agent, the surface sizing agent is a solution-type styrenic polymer, or An ink jet recording paper, which is a solution-type styrene-acrylic copolymer. 10 to 60 parts by mass of aluminum sulfate, 40 to 90 parts by weight of starch, and 0.1 to 2 parts by mass of the surface sizing agent with respect to 100 parts by mass of the surface size press treating agent. The inkjet recording paper according to claim 1.