JPS60257285A - Recording paper - Google Patents

Abstract

PURPOSE:To contrive enhancement of ink absorptivity, by a method wherein at least one ink-receiving layer is provided on a base while specifying the pigment/ binder ratio in the layer. CONSTITUTION:The ink-receiving layer is provided by applying to the base a coating liquid comprising a pigment, which is a pore-constituting material, and a binder. In this case, the binder is used in an amount of 60-200pts.wt. per 100pts. wt. of the pigment. A recording paper thus obtained shows a high color density and an enhanced ink jet recording adaptability.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Application of M Shelf The present invention relates to a recording medium recorded using ink, and in particular, images and characters recorded on the medium have a high density and a clear color tone. This paper relates to an inkjet recording paper that has excellent ink absorption ability and is particularly suitable for multicolor recording.0 The inkjet recording method uses various operating principles to fly minute droplets of ink onto paper or other paper. It is attached to a recording medium to record images, characters, etc., and it is used at high speeds and
It has features such as low noise, easy multicolor printing, great flexibility in recording patterns, and no need for development or fixing. It is rapidly becoming popular. Furthermore, images formed using the multicolor inkjet method can produce records that are comparable to multicolor printing using the plate-making method or printing using the 4-color method, and are suitable for applications that require fewer copies to be produced. Since it is cheaper than photographic technology, it is being widely applied to the field of full-color image recording.

Efforts have been made in terms of equipment and ink composition to use high-quality paper or coated paper, which are used for ordinary printing and writing, as the recording medium used in this inkjet recording method. However, as the performance of inkjet recording apparatuses increases, such as higher speeds, higher definitions, and full-color inkjet recording apparatuses, and their applications expand, recording media are now required to have better daylight characteristics. In other words, the recording medium must have a high ink dot density, a bright and cedar tone, a fast absorption of ink and no ink bleeding or bleeding even when ink dots overlap, and a high density ink dot. The lateral diffusion should not be larger than necessary, and the periphery should be smooth and not faded. Furthermore, it is required that the resistance of the dye when the recorded image is exposed to ultraviolet rays, oxygen in the air, or water is not reduced, and preferably is enhanced.

In order to solve these problems, several proposals have been made in the past. But also, Leopard Kaisho 53-49
No. 113 discloses an inkjet recording paper in which a sheet internally added with urea-formalin resin powder is impregnated with a water-soluble polymer. Although these patterned paper type inkjet recording papers absorb ink quickly, they have the disadvantage that the periphery of the dots tends to become blurred and the dot density is low. , an inkjet recording paper with an ink-absorbing coating layer provided on the surface of the support is disclosed, and JP-A-55-51583 discloses an example in which non-glue silica powder is used as a pigment in the coating layer. No. 55-11829 discloses an example of coated paper using a two-layer structure with different ink absorption speeds. These coated paper-type inkjet recording papers are improved over general paper-type inkjet papers in terms of dot diameter, dot shape, dot density, and color tone reproducibility, but they are inferior in terms of ink absorption capacity. However, many of them are still inferior to general paper-type inkjet paper.

(B) Purpose of the Invention The present inventor hereby proposes an inkjet recording method in which a recorded image is obtained by jetting inkjet ink onto a recording medium, and a method in which a recorded image is obtained by transferring or pressing recording ink and absorbing it into a recording medium. The present invention was developed as a result of extensive research into recording paper, in which the recording medium is a coated paper type, which satisfies the above-mentioned characteristics and has excellent absorbency.

(0) Structure of the Invention That is, the present invention provides a recording paper in which the recording medium has at least one ink-receiving layer on a support, and the pigment/binder ratio constituting the ink-receiving layer is 100/60 to 100/200. It is. Furthermore, since the support is made of paper that does not contain an internally added sizing agent, the recording paper has particularly excellent absorbency.

In the present invention, the ink-receiving layer refers to a layered layer having an ink-absorbing ability that can be accessed by coating a coating liquid consisting of a pigment and a binder, which are pore-forming materials, on a suitable support.

Examples of pore forming materials include calcium carbonate, kaolin (white clay), talc, calcium sulfate, barium sulfate,
Inorganic and organic materials such as titanium oxide, zinc oxide, lead carbonate, aluminum oxide, aluminum hydroxide, aluminum oxide, calcium silica, magnesium silicate, amorphous silica, synthetic zeolite and plastic pigments, and urea resin pigments. These pigments can also be used together.

Coating these pigments onto a support to form an ink receptacle requires a binder to adhere the pigments to the support, e.g. Oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, soy protein, polyvinyl alcohol and its derivatives, maleic anhydride resin, ordinary styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer Conjugated diene polymer latex such as polymer, acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester, vinyl polymer latex such as ethylene vinyl acetate co-paged polymer, or these. functional group-modified polymer latex with monomers containing functional groups such as carboxyl groups of various polymers, water-based adhesives such as thermosetting synthetic resins such as melamine resins and urea resins, and polymethyl methacrylate, polyurethane resins, and Synthetic resin adhesives such as saturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and alkyd resin can be used alone or in combination. These binders are pigment 1
00 parts, 60 parts to 200 parts, preferably 100 parts to 170 parts are used. In the present invention, this pigment/binder ratio is extremely important;
If the amount of binder is less than 60 parts per part, the adhesion of the pigment will be poor and this may cause clogging of the inkjet nozzle Q. Also, if a binder of 200 or more is used, the ink absorbency will be extremely reduced, impairing the performance as a recording paper.In addition, if necessary, pigment dispersants, thickeners, fluidity modifiers, and antifoaming agents will be added. , foam suppressants, mold release agents, foaming agents, penetrating agents, colored dyes, colored pigments, fluorescent whitening agents, ultraviolet absorbers, antioxidants, preservatives, anti-spiking agents, etc. can also be blended as appropriate. .

As the support, paper is used which has the ability to absorb an appropriate amount of the coating solution and adhere to it. These papers are papers in which the addition of internal sizing agents is limited in order to have appropriate absorbency, and it is most preferable that no internal sizing agents be added. In addition, the filler may or may not be included, but it is preferable to include an appropriate amount of filler in order to adjust the absorption amount and absorption rate. In this case, many of the fillers that are commonly used as fillers can be used, such as titanium oxide, calcium sulfate, carbonated calcium, light calcium carbonate, clay, talc, and amorphous silica.

The content of these is usually about 0 to 25%, preferably 5% to 20%.

Paper of a predetermined basis weight is made from a slurry to which pulp and, if necessary, a filler, a retention improver, a toning agent, etc. are appropriately added, using a fourdrinier paper machine or the like, and used as a support.

In this case, it is possible to improve the surface strength etc. by applying a water-soluble polymer liquid such as starch or polyvinylalconope acrylamide using a commonly used size press device, gut roll device, spray device, etc. Yes, there is no problem. In this way, a highly absorbent support for use in the present invention can be obtained.

To provide an ink-receiving layer on these supports, the coating solution is applied using a commonly used coating machine and dried. As a coating machine, a commonly used blade coater, air knife coater, roll coater, coater, curtain coater, bar coater, gravure coater, spray device, etc. can be used. The coating amount is 111/rn" to 301/rrl, preferably 3 g/m as dry solids.
"~18g/m". Coated paper can be used as it is as a recording paper according to the present invention, but 91, t 1
4. It may also be possible to impart surface smoothness by passing between roll nips under pressure and/or heat using a super calender, cross calender, or the like.

(DJ Examples The present invention will be explained below with reference to Examples, but it is not limited to these examples. In addition, parts and % shown in Examples mean parts by weight and % by weight.

Measurements of various physical properties in Examples were carried out in the following manner. First, an inkjet printer manufactured by Sharp Corporation (IO-
700), cyan (0), magenta (ro),
Image densities of images obtained by solid printing using yellow (Y) and black (Bi) inks were measured using a Macbeth densitometer RD514. The dot diameter was calculated by measuring the area of a single dot in the black ink area of the same inkjet printer using a dot area meter, converting it into a perfect circle and determining the diameter.

In addition, the ink absorption speed was determined by using the same color image printer and letting the red printed area (magenta + yellow) touch the paper presser roll immediately after solid printing (about 1 second), and checking whether stains appeared or not. 0 Furthermore, the ink absorption ability was determined by the degree of bleeding at the boundary of the solid printed area using the same inkjet printer.

Adhesion was determined by touching the surface of the support with the ink-receiving layer provided thereon before supercalendering.

Examples 1 to 5 Supports were prepared as follows: 80 parts of LBKP with an OF water level of 380 dc, s, f and a muddy level of 4.
Light calcium carbonate (Shiraishi Kogyo Co., Ltd.) was added to a pulp slurry consisting of 20 parts of NBKP of 10yul C, S, F.
14 parts of cationic lees # (Qato 1 manufactured by Tamako National Co., Ltd.) were added as a retention improver and a paper direction improving agent.
A base paper with a basis weight of 7011/m" was produced from a slurry containing ti15 of 02) using a Fourdrinier paper machine. At that time, using a size press installed in the middle of the Fourdrinier paper machine, polyvinyl alcohol was 2% ha was applied, dried, rolled up through a machine calender, and used as a support.The coating liquid contained 100 parts of synthetic silica (Syroid 404, manufactured by Fuji Deguyson) as a pigment, and polyvinyl alcohol (Kuraray HPV Al 17) as a binder. /PV
A 105 1/4 Nolent) 60.100 each
．． 140,170,200 parts were added, and five types were created with a concentration of 15%. These coating solutions were applied to the above support using an air knife coater to a dry solid content of 6117 m'', dried, and passed through a super calender to smooth the surface. The results of evaluating the inkjet suitability of these recording papers are shown in Table 1.

Comparative Examples 1 to 2 The pigment/binder ratio of the coating liquid was 100/40 and 100
Comparative Examples 1 and 2 were recording sheets prepared in exactly the same manner as in Examples 1 to 5, except that the paper was changed to /250. Table 1 shows the results of evaluating the inkjet suitability of these recording papers.
Shown below.

Examples 6-12 The support was manufactured as follows.

To a pulp slurry consisting of 91,380 ml of muddy water, 70 parts of BKP, and N'BKP30@ with a reactor water temperature of 410 at csf, 18 parts of Melk for drafting was added.
Using a fourdrinier paper machine, a paper sheet with a basis weight of 7,817 m was prepared from a slurry containing 1 part of cationic starch (0ato 102 manufactured by Tamago Nashina Narukari Co., Ltd.) as a paper orientation agent and 0.01 s of high molecular weight polyacrylamide as a yield improving material. A base paper is made, and a size press liquid prepared by adding 0.1% of a fluorescent agent to a 4% solution of phosphorized starch (Ms3800 manufactured by Nihon Shokuhin Co., Ltd.) is applied using a size press device installed in the middle of the paper machine.7 This was used as a support, and on top of it, a planting solution with a dry solid content of 17% consisting of 100 m of synthetic silica (Syroid 74, manufactured by Shishi Devin) and 120 parts of polyvinyl alcohol (pvAllO, manufactured by Kuraray) was applied using an air knife coater. The song Macasagi is 2.5.10゜15.20.25.3011
Examples 6, 7, and 7 were prepared by drying, passing through a super calender, and smoothing the surface.
Recording paper of 8°9.10 and 11.12 was used. Table 2 shows the results of evaluating the inkjet permeability of these recording papers.

Table 1 Table 2 Example 13 The support was manufactured as follows: T, B K P 80 with an OF water content of 380ffi/csf
20 parts of NBKP with tear water content of 410 and 1 c8 tons of waste, 18 parts of talc for drawing, 1 part of cationic starch, and alkyl ketene dimer (tick, ) -- Kineles type Nore-Con w
) From the slurry consisting of 0.06i, a base paper of 6417 m' in area was made using a Fourdrinier paper machine in a conventional manner, and a 5% solution of oxidized starch was applied using a size press installed in the middle to form a support. did. The Steckt size degree of this support was 11 seconds.

On top of this, 70 parts of synthetic silica (Syroid 72 manufactured by Fuji Davison) as a pigment, 30b' (5) of synthetic zeolite (zeolite manufactured by Nippon Birgoo) and 120 parts of polyvinyl alcohol (PVX105 manufactured by Kuraray) as a binder are dried and solidified. The paper was coated with an air knife coater to give a coating density of 18 g/m'' per minute, dried and smoked, and passed through a super calender to smooth the surface to obtain the recording paper of Example 13.

Comparative Example 3.4 On the support used in Example 13, the same
Comparative Example 3.4 and Comparative Example 3.4 and 220 parts of polyvinyl alcohol (Cran mpuAt05) were added to the pigments used in Example 13 and 30 parts and 220 parts of polyvinyl alcohol (Cran mpuAt05) as a binder, respectively, were coated and finished in the same manner as in Example 13. did. Table 2 shows the results of evaluating the inkjet permeability of these recording papers.

(E) Effects of the Invention As is clear from Table 1.2, the recording papers for Yoke 1 (Actual JM Examples 1 to 13) with pigment/binder ratios of 100/60 to 100/200 have a dark color and are not forged. Furthermore, it also has excellent inkjet compatibility, making it suitable for use in inkjet recording.

Claims (2)

[Claims] (1) Recording paper comprising at least one ink-receiving layer provided on a support, characterized in that the pigment/binder ratio constituting the ink-receiving layer is 100/60 to 100/200. Paper. (2) The recording paper according to claim 1, wherein the support is paper to which no internal sizing agent has been added.