JPH01255580A - Coated sheet for ink jet recording - Google Patents

Abstract

PURPOSE:To enable high-speed color printing of characters and graphic images with high resolution, by providing a coated layer comprising silica and an adhesive at a specified mixing ratio as essential constituents on a sheet-shaped base. CONSTITUTION:A coating material obtained by mixing of 15-65wt.% of silica, which is one of highly oil-absorptive inorganic pigments, with 10-50wt.% adhesive is applied to a surface of a sheet. In this case, an oil-absorptive inorganic pigment, which is a color developing white pigment having a high oil absorptiveness and a high specific surface area, and an organic pigment may be used also. If the silica content is less than 15wt.%, an oil-based ink can not be adsorbed satisfactorily, so that fixability of the ink is poor. If the silica content exceeds 65wt.%, the adhesive strength of the coated layer becomes insufficient, causing cracking or delamination of the coated layer or dusting. The adhesive to be used in the coated layer may be any of various adhesives soluble or dispersible in an organic solvent or water. If the amount of the adhesive is more than 50wt.% based on the solid components of the coating material, it is difficult to realize high resolution of images. If the amount of the adhesive is less than 10wt.%, the effect of the adhesive is generally lost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coated sheet for recording used in inkjet image printers etc. using oil-based ink, that is, hydrophobic liquid ink. The image is water resistant and can be processed and written on in the same way as general high-quality paper or coated paper, but the absorption speed and absorption capacity of the ink attached to the sheet surface is high, and the ink color is vivid and sharp. It is a novel product with excellent recording characteristics such as giving beautiful images and printing.
Related to Recording Sheets 6 O [Prior Art] The technology of inkjet color printers that create color hard copies at high speed using an inkjet recording method is progressing. In order to obtain a high-quality recording surface [T-], the water-based ink attached to the recording sheet does not spread over the surface and is quickly absorbed in the thickness direction. A sheet with a layer has been proposed.

For example, Japanese Patent Application Laid-Open No. 55-51583 discloses a laminated layer consisting of non-silica silica (particle size α1 to 10 μm) and a polymer binder for inkjet printers using water-based ink. The publications each disclose that a receiving layer consisting of particulate silicic acid and a non-aqueous bath agent soluble resin, or comprising particulate silicic acid, other inorganic pigment particles, and a non-aqueous solvent soluble resin is provided on a substrate.

However, the biggest drawback of water-based inkjet printing is the lack of ink nozzles. This is thought to occur when the hydrophilic solvent evaporates and the inorganic salt dissolved in the ink precipitates.

An oil-based inkjet printer has recently been reported in order to improve image clarity, water resistance, and printer reliability by using oil-based ink in an inkjet method (Japanese Patent Laid-Open No. 61-91276).

The principle of this inkjet printer is to form an image by ejecting oil-based ink using methods such as electrostatic acceleration type, pressure jetting, pressurized vibration type, and pressure pulse type.

[Problem that the invention seeks to solve]

The present invention has a good oil-based inkjet recording suitability of 9:t, that is, the absorption speed and absorption capacity of the oil-based ink attached to the surface of the recording sheet are high, the color of the ink is bright, and the ink dots do not bleed. The small, circular ink dot shape provides sharp images, and therefore allows for high-resolution printing and printing.
I! A coated sheet for oil-based inkjet printer recording that enables high-speed color printing.More specifically, the coated layer has a high surface strength and the 2-dot diameter is larger than conventional ones, so there is no powder falling off. The purpose is to provide a coated sheet for oil-based inkjet printers that has good processing suitability and has excellent water and moisture resistance for images. Paper and polymer film-based synthetic paper made mainly from natural pulp To provide a recording sheet that can be used in an environment exposed to high humidity or water droplets, while taking full advantage of the full color performance of an inkjet printer due to its high speed and high resolution. It was difficult.

[Means for solving problems]

In order to solve the above-mentioned drawbacks of the prior art, the present inventors have made extensive studies and found that silica, which is one of the highly oil-absorbing inorganic pigments, contains 15 to 65% by weight of t? 10~. VC! on the sheet surface by mixing with 50% by weight adhesive! l! To construct and use v
R-processing, high absorption speed and absorption capacity of oil-based ink,
Ink color development: J (bright, small ink dot bleed, large dot diameter, and circular ink dot shape, giving a sharp image, making it possible to print high-resolution characters and images at high speed. It has been found that a thin inkjet recording sheet with excellent surface strength can be obtained. If the silica content is 15 wt% less, the oil-based ink cannot be completely absorbed, resulting in poor fixing properties. If it is more than that, the adhesive strength of the coating layer will be insufficient, causing cracking, peeling, and powder falling of the coating layer.

In the present invention, it is known that clear images can be obtained when used as a pigment in thermal transfer receiving paper.

An oil-absorbing inorganic pigment, which is a color-developing white pigment having a high oil absorption amount and a high specific surface area, and an organic pigment can also be used together.

This is because the ink used for thermal transfer is a hydrophobic liquid (at least for printing lines) similar to oil-based inkjet.

As the oil-absorbing inorganic pigment used in combination, Merck, charcoal-modified calcium, calcined clay, etc. are preferable. As organic pigments, polymeric microspheres having glass transition points above room temperature, such as urea-formalin resin, polystyrene, and polymethyl methacrylate, give excellent results. Since the ink droplets are less than 100μm, the average particle size of the pigment is 50μm.
m or less, and preferably 25 μm or less.

As the adhesive for the coating layer, various organic solvent-soluble or dispersible adhesives or water-soluble or water-dispersible adhesives can be used. Styrene-acrylic acid ester copolymer latex, polyester, styrene-butadiene copolymer latex, and polyvinyl alcohol are particularly preferred, and these adhesives may be used in combination. These adhesives are applied after being dissolved or dispersed in an aqueous medium or an oily medium. If the amount of adhesive is 50% by weight or more based on the solid content of the paint, it will be difficult to achieve a high image coverage, so the amount of adhesive #i should be 50% by weight or less, preferably 30% by weight or less based on the solid content of the paint. do.

Below 10%, the effect is generally lost.

- When going boat fishing, the amount of coating on the support is 1 to 40 f.
/ m", preferably 5 to 20 f/m".If the coating layer is too small, the ink absorbency will be insufficient, and if it is too large, it will be uneconomical, unsatisfactory, and the strength will decrease.

In addition, the dot diameter can be controlled to be small or large depending on the surface activity of the ink by containing a surface-active polymer substance such as polyethylene oxide or polypropylene oxide, which is a lipophilic nonionic surface active agent, in the coating layer as a dot control agent. can do.

As the support used in the present invention, in addition to paper, various films such as synthetic paper can be used depending on the purpose. The thickness of the sheet-like support is 10 to 200 μm1 and the basis weight is 10 to 200 μm.
200 t/m'' is preferable, and one with good surface smoothness is preferable.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the examples, parts indicate parts by weight as solid content.

Example 1 Paint-1 Silica (P78A: Mizusawa Chemical) 100
Surfactant (Tenro: San Nopco) 1
Water-based paint with a concentration of 35% by weight from 2 parts or more of ingredients-1
The solid content was 10 t/m” on a multilayered synthetic paper Yubo 5GG80 (80 μm thick Oji Yuka synthetic paper) containing an inorganic pigment as a support, dried, and smoothed with a super calender. An oil-based inkjet sheet was obtained by chemical treatment. Bekk smoothness of the coated surface (Oken method)
was 2000 seconds, and the smoothness of the opposite side was 550 seconds.

Example 2 Paint-2 Silica (P78A: Mizusawa Chemical) 80
Prepare paint-2 with a concentration of 30% from more than 100% of the ingredients,
An oil-based inkjet sheet was obtained by coating a 6597 m" high-quality paper with an X solid content of 1017 m", drying, and smoothing with a super calender. The Bekk smoothness of the coated surface (Ouken style) is 600 seconds, and the smoothness of the opposite side is 105.
It happened in seconds.

Implementation fI13 Paint-3 Dispersant (Tenroa 0: San Nopco Co., Ltd.)
Paint-3 with a concentration of 30% is prepared from components of 1.5 m or more, and multilayered synthetic paper YUPO 5 contains inorganic pigments as a support.
A solid content of 1017 m'' was coated on GG80 (Oji oil-based synthetic paper with a thickness of 80 μm), dried, and smoothed using a super calendar to obtain an oil-based inkjet sheet. The smoothness of the opposite surface was achieved in 550 seconds.

Comparison 9111 Paint-4 Pigment calcium carbonate (pc: Shiraishi Kogyo) 100
A 6,597 m'' high-quality paper was bound as a support, and the paint of Comparative Example 1 was coated in a solid amount of 1,017 m'', dried, and smoothed using a supercalender to obtain an oil-based inkjet sheet. The Bekk smoothness of the coated surface (Oken method) is 3
The smoothness of the opposite side was achieved in 105 seconds.

Ratio 4! ! 2 Example 2 Paint-5 Pigment 60j1m polyester film as support Comparative example 2
A coating material of 1097 m'' was applied as a solid content, dried, and smoothed using a super calendar to obtain an oil-based inkjet sheet.

The Bekk smoothness (Ouken method) of the coated surface was achieved in 10,000 seconds, and the smoothness of the opposite surface was achieved in 550 seconds.

Table 1 shows the evaluation results of these oil-based inkjet recording sheets. Custom-made oil-based inkjet recording uses a microsyringe to drip oil-based ink to improve ink absorption and
Regarding the clarity of color development, the strength of the coating layer was evaluated by cellophane tape test and pencil writability.

For ink absorption evaluation, the time taken for the ink to dry was measured.

The clarity of color development was visually evaluated by the color development of yellow, magenta, and cyan color inks and the color development of green, blue, and red heavy colors.

Pencil writability was sensually judged based on the difficulty of writing with an H pencil.

The surface strength was determined by peeling off the cellophane tape and sensory evaluation of the degree of disintegration of the coating layer.

Image water resistance was determined by immersing the image in running water for 5 minutes, drying it, and checking whether the image remained.

The sheet water resistance was determined by pasting the entire sheet on which the image was recorded on a P2stick board with a water-resistant adhesive, immersing it in running water for 2 hours, and then visually observing for wrinkles, crevices, breaks, etc.

◎ indicates a product with particularly excellent performance, 0 indicates a product with excellent performance, Δ indicates general quality, and × indicates a product with defects that may cause problems in use.0Table-1 [Effects of the invention] The coating layer of the oil-based inkjet recording sheet of the present invention has a strong surface, can be written on easily with a pencil, has excellent ink absorbency, and has excellent brightness of one color.It has a high viewing angle that eliminates the drawbacks of conventional methods. , high-speed, general-purpose oil-based inkjet
Power 2--It is what makes printers possible.

Claims (1)

[Claims] 1. For oil-based inkjet recording containing a colorant, characterized in that a coating layer containing 15 to 65% by weight of silica and 10 to 50% by weight of an adhesive is provided on a sheet-like support. Coating sheet.