JP2001039017A - Recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cockling (waviness) in the case of ink jet recording by laminating a split fiber nonwoven fabric on one surface of raw paper of an ink jet recording sheet. SOLUTION: Since a recorded sheet is elongated in the case of absorbing an ink when cockling occurs in an ink jet recording sheet, the cockling when ink jet recorded is prevented by laminating a split fiber nonwoven fabric. As the split fiber nonwoven fabric, it means a nonwoven fabric of a continuously mesh-like state, and a split fiber nonwoven fabric made of a polyethylene is preferably used. As a means for laminating the split fiber nonwoven fabric on raw paper, a method of dry laminating, wet laminating, sand laminating, heat fusion bonding or the like can be used. Further, it is preferred to coat an opposite surface of the raw paper to the split fiber nonwoven fabric with an ink receiving layer. As the ink receiving layer, one or more types of white pigments can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet in which cockling does not occur when ink jet recording is performed.

[0002]

2. Description of the Related Art Ink-jet recording is a method in which minute droplets of ink are made to fly and adhere to a recording sheet such as paper by various operating principles to record images and characters. It has features such as easy multi-coloring, great flexibility in recording patterns, and no need for development-fixing.
It is rapidly spreading in various uses as a recording device for various figures and color images including kanji. Furthermore, the image formed by the multi-color ink jet method is compared with the multi-color printing by the plate making method and the printing by the color photographic method,
It is possible to obtain comparable records. In applications where the number of copies required is small, it is being widely applied to the field of full-color image recording because it is cheaper than the photographic technique.

As recording sheets used in the ink jet recording system, efforts have been made in terms of apparatuses and ink compositions in order to use high-quality paper and coated paper used for ordinary printing and writing. However, with the improvement of the performance of ink jet recording apparatuses such as high-speed, high-definition and full-color apparatuses, and expansion of applications, more advanced characteristics are also required for recording sheets.

[0004] That is, the recording sheet has a high density of print dots, a bright and vivid color tone, quick absorption of ink, no ink bleeding or bleeding even when the print dots overlap, High image reproducibility is required such that the diffusion in the horizontal direction is not unnecessarily large and the periphery is smooth and not blurred.

[0005] Further, with the spread of the ink jet recording system, large-sized posters or signboards, which have been produced in large quantities by conventional printing or the like, have been reduced to a large variety of small lots due to the diversification of user preferences. Printing by a large-sized inkjet printer is increasing. Therefore, when the size of the paper increases, cockling (wavy) occurs after printing, which is inconspicuous in A4 size or the like which has been printed by a conventional small printer, and a problem arises that printing quality is deteriorated. I was As a countermeasure against cockling, the base material of the ink jet recording sheet may have a laminated structure. However, the base material having a laminated structure tends to increase the thickness of the base material and hinder printer conveyance. was there.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording sheet which does not cause cockling during ink jet recording.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the following invention.

That is, an invention of an ink jet recording sheet characterized in that a split fiber non-woven fabric is bonded to one surface of a base paper.

The ink jet recording sheet according to the invention is further characterized in that an ink receiving layer is provided on the surface of the base paper opposite to the split fiber nonwoven fabric.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet recording sheet of the present invention is characterized in that it is bonded to a split fiber nonwoven fabric. The reason why cockling occurs in the inkjet recording sheet is that the recording sheet expands when ink is absorbed. The split-fiber nonwoven fabric used in the present invention is generally bonded together in order to improve the strength of the sheet.However, the present inventors apply cockling during inkjet recording by bonding the split-fiber nonwoven fabric. Found to prevent. Since the split fiber non-woven fabric is a mesh-like non-woven fabric, there are many portions of the base paper that are not in contact with the split fiber non-woven fabric. However, with such an area, strangely, cockling does not occur. That is, it is presumed that cockling does not occur unless elongation of the base material occurs unless the contact area of the laminated base material is at least a certain level.

The base paper used in the present invention is composed mainly of wood pulp and pigment. As wood pulp,
Chemical pulp such as LBKP, NBKP, GP, PGW, R
MP, TMP, CTMP, CMP, including mechanical pulp such as CGP, pulp such as waste paper pulp such as DIP, if necessary conventionally known pigments and binders and sizing agents and fixing agents, retention agents, cationizing agents, A mixture of one or more additives such as a paper-strength enhancer is used, and the support can be manufactured using various devices such as a fourdrinier paper machine, a circular web paper machine, and a twin-wire paper machine. Can be made alkaline.
When an ink receiving layer is provided, the ink receiving layer may be provided on the base paper as it is, or a size press using starch, polyvinyl alcohol, or the like, or a multi-layer ink in which an ink receiving layer is provided after providing an anchor coat layer. It may be a receiving layer.

Further, the base paper may be subjected to on-machine processing of a calender device comprising a metal roll and a synthetic resin roll. At that time, off-machine processing may be performed, and after processing, flatness may be controlled by further performing calendar processing using a machine calendar, a super calendar, or the like.

In the present invention, the split-fiber nonwoven fabric includes
It refers to a continuous mesh-like nonwoven fabric, preferably a polyethylene split fiber nonwoven fabric. In addition, as a means for laminating and bonding the base paper and the split fiber non-woven fabric, known techniques such as dry lamination, wet lamination, sand lamination, and heat fusion can be used.

In the present invention, when the ink receiving layer is provided on the surface of the base paper opposite to the split fiber non-woven fabric, the coating amount is not particularly limited. Although the absorbency is good, the image density, color, and sharpness are low, the ink diffuses in the surface direction of the base paper, and the deterioration of the dot shape called feathering jagged like bird feathers occurs,
There is no point in providing an ink receiving layer. Further, when the coating amount is too large, the drying load in the drying step after coating increases, and not only does the productivity decrease due to a decrease in the coating speed, but also the drying under high load constitutes the ink receiving layer. The binder in the coating composition moves to the surface of the ink receiving layer together with the solvent that evaporates, and reduces the amount of voids on the surface. The problem which occurs in the ink receiving layer having a large coating amount is affected by the concentration of the coating composition and the ability of the drying step, but is preferably 1 to 10 g / m ^2.
It is.

In the base paper and ink receiving layer used in the present invention, one or more known white pigments can be used.
For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic non-crystalline White inorganic pigments such as crystalline silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloysite, magnesium carbonate, magnesium hydroxide, styrene-based plastic pigments,
Organic pigments such as acrylic plastic pigments, polyethylene, microcapsules, urea resins, melamine resins, and the like. Among the above, as the white pigment contained as the main component in the ink receiving layer, a porous inorganic pigment is preferable, and a porous synthetic amorphous silica, a porous magnesium carbonate, a porous alumina, and the like, and particularly, a pore volume Large porous synthetic amorphous silica is preferred.

Examples of the adhesive include polyvinyl alcohol, vinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, casein, gelatin, and the like.
Soy protein, silyl-modified polyvinyl alcohol, etc .; conjugated diene copolymer latex such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer;
Acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester, polymer or copolymer of acrylic acid and methacrylic acid; vinyl polymer latex such as ethylene vinyl acetate copolymer; or Functional group-modified polymer latex by a monomer containing a functional group such as a carboxyl group of these various polymers; aqueous adhesives such as thermosetting synthetic resin systems such as melamine resin and urea resin;
Synthetic resin-based adhesives such as polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and alkyd resin are used, and one or more of them are used.

Further, other additives include a pigment dispersant, a thickener, a flow improver, an antifoaming agent, a foam inhibitor, a release agent,
Blowing agents, penetrants, coloring dyes, coloring pigments, fluorescent whitening agents, ultraviolet absorbers, antioxidants, preservatives, anti-binders, water-proofing agents, wet paper strength enhancers, dry paper strength enhancers, etc. It can also be blended.

The method for coating the ink receiving layer on the base paper of the present invention is performed by using various apparatuses such as a blade coater, a roll coater, an air knife coater, a bar coater, a rod blade coater, a short dwell coater, and a size press. Alternatively, it can be used off-machine. Further, after coating, finishing may be performed using a calendar such as a machine calendar, a TG calendar, a super calendar, and a soft calendar.

In the ink jet recording sheet of the present invention, since the split fiber non-woven fabric is bonded to the base paper, when the ink is absorbed, the split fiber non-woven fabric suppresses the elongation due to the water absorption of the base paper and generates cockling. Therefore, it is effective without rubbing with the print head.

[0020]

EXAMPLES The present invention will be described below with reference to examples of the present invention, but the present invention is not limited to these examples. In Examples and Comparative Examples, “parts” and “%”
Unless indicated otherwise, parts by weight and% by weight are indicated.

Example 1 The base paper was made of a ratio of light calcium carbonate / heavy calcium carbonate / talc to 100 parts of wood pulp composed of 70 parts of LBKP (freeness of 400 mlcsf) and 30 parts of NBKP (freeness of 450 mlcsf). Is 25/30/35/35 pigment, 0.10 part of commercially available alkyl ketene dimer, 0.03 part of commercially available cationic acrylamide, 1.0 part of commercially available cationized starch, and 0.5 part of sulfate band. The paper was made at a basis weight of 40 g / m ² using a net paper machine.

Next, a split-fiber nonwoven fabric (Nisseki Warif SS, manufactured by Nisseki Plast Co., Ltd.) is overlaid on one side of the base paper, and is heated and fused by applying a hot roll and bonded to each other. A recording sheet was obtained.

Example 2 An ink receiving layer was provided on the surface of the base paper made in Example 1.
As an ink receiving layer composition, 100 parts of synthetic amorphous silica (Fanseal X37B: manufactured by Tokuyama Soda Co., Ltd.) and polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) 30
Parts, cationic dye fixing agent (SUMIREZ Resin 100
1: Sumitomo Chemical Co., Ltd.), and the solution was prepared to have a solid content of 13%. Using the prepared ink receiving layer coating solution, the surface of the support was coated with an air knife coater so as to have a dry coating amount of 5 g / m ² to obtain an ink jet recording sheet.

Next, a split-fiber nonwoven fabric (Nisseki Warif SS, manufactured by Nisseki Plast Co., Ltd.) is overlaid on the base paper surface of the ink jet recording sheet, and a hot roll is applied thereto and heat-sealed to be bonded. An ink jet recording sheet was obtained.

Comparative Example 1 The base paper produced in Example 1 was used as an ink jet recording sheet of Comparative Example.

Comparative Example 2 The ink jet recording sheet prepared in Example 2 was used as a comparative ink jet recording sheet.

Comparative Example 3 An ink jet recording sheet was obtained by laminating polypropylene on one side of the base paper prepared in Example 1 using a melt extrusion die so as to have a thickness of 10 μm.

Comparative Example 4 Polypropylene was laminated on the base paper surface of the ink jet recording sheet prepared in Example 2 to a thickness of 10 μm using a melt extrusion die to obtain an ink jet recording sheet.

<Test Method> 1) Ink Drying Properties The recording sheets prepared in Examples and Comparative Examples were cut to A4 size, and then each color of black, cyan, magenta and yellow was printed by an ink jet printer (JV2-130 manufactured by Mimaki Engineering). Multicolor black printing consisting of 100% is performed. Immediately after printing is completed, PPC paper is superimposed on the printing section,
After rubbing from above and transferring the undried ink to PPC paper, the density of the printed portion was measured by Macbeth RD919. A smaller value indicates better ink drying property.

2) Cockling The recording sheets prepared in Examples and Comparative Examples were cut into A4 size papers, and a 100% overlapped black, cyan, magenta, and yellow color was printed using an inkjet printer (JV2-130 manufactured by Mimaki Engineering). Print almost the entire surface in black and white. After the printing is completed, the degree of cockling is visually observed. If no cockling has occurred, the cockling is excellent, and if there is slight cockling but not yet rubbed against the head, the cockling is lined up. The cockling was judged to be inferior in those that had been lost.

3) Printer transportability After the recording sheets prepared in Examples and Comparative Examples were cut to A4 size, an ink jet printer (Epson PM
At −750 C), five sets of continuous printing are performed with 20 sheets as one set. The transport trouble occurrence rate such as heavy running is calculated from the number of troubles and the number of times of printing. The lower the trouble rate, the better the printer transportability.

[0032]

[Table 1]

Evaluation: As is clear from the table, cockling does not occur at all in Examples 1 and 2, which are the ink jet recording sheets of the present invention. Even if a laminate layer is provided on the surface opposite to the print surface as in Comparative Examples 3 and 4, the base paper and the laminate layer are stuck together on the entire surface. Although better than the ink jet recording sheet, it does not reach the ink jet recording sheet of the present invention. Further, it can be seen that the ink jet recording sheet of the present invention has good ink drying properties.

Further, it can be understood that cockling does not occur, and that the printer has good transportability because the rigidity is appropriate even when the nonwoven fabric is laminated.

[0035]

The ink jet recording sheet of the present invention is
There is no cockling due to stretching of the base paper during printing,
It is effective to show good printability and printer transportability.

Claims (2)

[Claims] 1. An ink jet recording sheet wherein a split fiber nonwoven fabric is bonded to one surface of a base paper. 2. An ink receiving layer is provided on the surface of the base paper opposite to the split-fiber nonwoven fabric.
The ink jet recording sheet according to the above.