JPS62214987A - Recorded material - Google Patents

Abstract

PURPOSE:To improve an ink absorption as a recorded material for an ink jet recording and prevent bleeding and feathering to obtain a recording image being enhanced in dot-shape, color properties, density, and resolving power, by a method wherein a substrate of a recorded material is made from a pulp having a specific physical properties and a coated layer of a porous pigment is formed on the substrate. CONSTITUTION:A recorded material consisting of a substrate made of a pulp of 37-60 deg. SR in Schopper freeness and a porous pigment layer formed thereon can eliminate various problems in the prior art. On the other hand, a recorded material having a substrate made of a pulp of 37 deg. SR or below in Schopper freeness fails to form a high-quality image as a recorded material for water- color ink, particularly for an ink jet system, even if having the porous pigment layer. A recorded material having a substrate made of a pulp of 60 deg. SR above in Schopper freeness lowers in its opaqueness and stiffness and the like even if forming the porous pigment layer, thus becoming unsuitable for the use as a recorded material of paper series and inferior in appearance as a recorded material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recording material, and more particularly to a recording material for inkjet recording for recording with aqueous ink.

(Prior art) Inkjet recording methods use various inks (recording liquids).
Discharge methods, for example, electrostatic suction methods, methods that apply mechanical vibration or displacement to ink using piezoelectric elements, methods that heat ink to foam and use the resulting pressure, etc., are used to generate small droplets of ink. Recording is performed by emitting, flying, and attaching some or all of them to a recording material such as paper, but it is attracting attention as a recording method that generates little noise and allows high-speed printing and multicolor printing. There is.

As the recording material used in this inkjet recording method, commercially available heavy to medium-quality paper generally called plain paper and recording material called inkjet recording paper have been used.

Although commercially available medium-quality papers have excellent writing properties and printability, they have the following drawbacks when subjected to inkjet recording.

(1) During or after inkjet recording, if a part of the recording device or your finger touches the recording section, the ink will not be received quickly and the ink that has not been accepted will rub off.
Staining occurs and image quality is significantly degraded. Furthermore, the records may become illegible.

(2) After the ink adheres to the recording material, feathering occurs from the dots, resulting in dots with extremely low roundness. For this reason, the dot shape is poor and a clear image cannot be obtained.

On the other hand, various recording materials have been devised as recording materials for inkjet recording in order to obtain high-resolution, high-quality recorded images as the performance of inkjet recording JlvtW1 has improved and expanded. 59-35977, JP 58-132586, JP 52-74
(See Publication No. 340).

However, ``Unexamined Japanese Patent Publication No. 59-35977,
The recording materials described in Japanese Patent No. 8-132586 and the like are coated papers for inkjet recording that have high ink absorbency and excellent color development, but these recording materials have the following drawbacks.

(3) When writing on a recording material with a writing instrument such as a pencil or a fountain pen, the ink receiving layer is scratched and the writing cannot be done properly.

(4) When inkjet recording is performed on the recording material.

Mechanical friction between the recording material and the paper feeding part of the recording device causes the coating layer to peel off, which is called powder falling off.
Contaminate recording equipment. In particular, if the fallen ink receiving layer adheres to the head of an inkjet recording device, it may cause clogging of the nozzles of the head.

Further, the inkjet thick paper described in Japanese Patent Application Laid-open No. 52-74340 and the like has the following drawbacks when inkjet recording is performed.

(5) Low dot density.

(6) The dot periphery tends to be blurred, making it impossible to obtain a clear image.

(7) A phenomenon in which ink oozes out to the back side of the recording surface, so-called strike-through, occurs.

Conventional recording materials have the above-mentioned drawbacks.

At present, a recording material that solves all of these drawbacks has not been obtained.

Therefore, it is an object of the present invention to provide a high-performance inkjet that solves the above-mentioned drawbacks, has rapid ink absorption, has excellent dot shape, and forms clear images with especially good color properties and high image density. The object of the present invention is to provide a recording material for recording.

(Disclosure of the Invention) That is, the present invention has a Schopper freeness of 37 to 60@
This is a recording material characterized by coating a porous pigment on a base material containing SR pulp.

In addition, the Schopper freeness referred to in Kihasu 1 is J
This is a value measured according to IS-P8121, which is a guideline for the beating degree of pulp, and can be adjusted by controlling the beating degree of pulp.

Next, the present invention will be explained in more detail. 1. As a result of intensive research to obtain a recording material for inkjet recording using water-based ink, which solves the drawbacks of the prior art, the present inventor has developed a specific When forming the base material of a recording material from pulp with physical properties and forming a coating layer made of porous pigment on the base material, it is necessary to use a recording material for inkjet recording that has excellent ink absorbency and is free from ink bleeding. It was found that the recorded image was free from feathering, gave an excellent dot shape, had particularly good color properties, and had a high density and high resolution.

That is, the Schopper freeness of the pulp constituting the base material of the recording material of the present invention is 37 to 60°SR, and when forming the porous pigment layer thereon, the pulp constituting the base material of the recording material of the present invention is A recording material in which the problem has been solved can be obtained, and on the other hand, when the Schopper freeness is less than 37°SR, even if a porous pigment layer is formed, a recording material using aqueous ink can be obtained. In particular, as a recording material for an inkjet system, a high quality image cannot be formed. On the other hand, in the case of a recording material made of pulp with a Schopper freeness exceeding 60°SR, even if a porous pigment layer is formed, the opacity, rigidity, etc. of the resulting recording material will decrease. The recording material of the present invention is unsuitable as a paper-based recording material and has a poor appearance as a recording material. The best results were obtained when forming.

In the prior art, the pulp used for the paper yarn recording material has a freeness of 400 to 300 according to the Canadian method.
There are also known examples of using milliliter pulp.
According to Hita and Oe, p. 14), in the case of freeness measured using the Canadian method, the measured value of moss is inaccurate and has low accuracy due to high freeness. While it was not possible to determine the correlation between ink absorption, feathering, dot shape, and other physical properties, Schopper freeness values were accurate and, moreover, unexpectedly It has also been found that there is a good correlation with the characteristics of the recording material.

A base material containing a pulp having a specific Schopper freeness as described above has various suitability as a base material for a recording material, especially a recording material for an inkjet system.
When forming a base material from such pulp, when the amount of filler added is 6% by weight or more, preferably 8% by weight or more as ash, the ink absorbency to water-based ink during recording and the shape of the dots formed It was found that the results were further improved.

Preferred fillers to be added to the base material include silica, clay, tar, kaolin, diatomaceous earth, calcium carbonate, calcium sulfate, satin white, aluminum silicate, alumina, zeolite, etc. Particularly preferred is a particle size of 0.051L.
m to 50 m, more preferably 0. If the zero particle size, which is from lμm to 20m, is too large, the degree of bleeding of the aqueous ink in the horizontal direction of the substrate will become uneven.
Undesirable.

Furthermore, the ink absorbency, dot shape, etc. of the base material of the recording material of the present invention are further improved by setting the Steckigt sizing degree to 5 seconds or less, preferably 2 seconds or less, and most preferably 1 second or less.

The recording material of the present invention can be obtained by forming a coating layer from a porous pigment on a paper coat made from a pulp having a specific Schopper freeness as described above.

Examples of porous pigments used to form such a coating layer include fine powder silica, clay, talc, kaolin,
Examples include diatomaceous earth, TX-I'S calcium, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, satin white, aluminum silicate, lithopone, etc. Among these, particularly preferred pigments have an average particle size of I. #Lm~2
If the 0 particle size of 0 μm silica is too large, it is not preferable because the degree of bleeding of the aqueous ink in the horizontal direction of the recording material becomes uneven.

The coating layer made of the porous pigment is formed by dispersing the porous pigment in a medium such as water to a concentration of, for example, 5 to 50% by weight, adding an appropriate binder, and forming a coating liquid. By preparing the coating solution and applying the coating solution to the above substrate by a known method, for example, a roll coater method, a bar coater method, a blade coater method, an air knife coater method, a size press method, a gate roll method, etc. It will be done. The thickness of the coating layer is usually 1 to 15 pm (dry coating amount), preferably 2 to 1 pm.
It is about 2 μm.

Examples of the binder used in the above include water-soluble polymers such as starch, gelatin, casein, gum arabic, sodium alginate, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, and sodium polyacrylate, or synthetic rubber latex. Any conventionally known binder such as synthetic resin latex, water-insoluble polymers such as polyvinyl butyral and polyvinyl chloride can be used. These polymers are preferably used in a proportion of about 10 to 200 parts by weight per 100 parts by weight of porous pigment.

The recording material of the present invention obtained as described above is mainly recorded using water-based ink, and since such water-based ink is generally an aqueous solution of water-soluble dye, ink can be injected by the method described above. If the absorbency is increased, the dye in the aqueous ink will sufficiently permeate into the recording material together with the liquid medium, resulting in insufficient image density formed on the surface. Furthermore, since the dye is a water-soluble dye, the water resistance of the image formed is not necessarily sufficient, and problems such as blurring of the image occur when water droplets adhere to it.

In order to solve these problems, the present inventor conducted research to obtain a recording material that provides excellent ink absorption, excellent dot shape, and high color density as well as images with high density. Or, by adding a specific compound to the coating layer, that is, a compound that causes the water-soluble dye in the applied water-based ink to immediately precipitate on or near the surface of the recording material, the liquid medium in the applied water-based ink can be added to the coating layer. It has been found that, while the ink is rapidly absorbed into the interior of the recording material, the water-soluble dye in the water-based ink immediately precipitates on or near the surface of the recording material, giving high image density.

Since acid dyes and direct dyes are often used as water-soluble dyes in water-based inks, preferred compounds that have the above effects are alkali metals, alkaline earth metals, and other metals, such as , water-soluble metal salts such as lithium, potassium, sodium, magnesium, calcium, aluminum, strontium, manganese, etc., such as halides, carbonates, sulfur salts, sulfites,
Examples include nitrates, and halides of polyvalent metals such as alkaline earth metals are particularly preferred because they allow the water-soluble dye to be immediately precipitated without changing the hue of the water-soluble dye in the aqueous ink.

Among water-soluble metal salts, some are acidic, and these salts can unevenly dissolve the sizing agent in the recording material, making the water-based ink permeate unevenly, damaging the dot shape, and even damaging the dot shape. This is not very preferable because it changes the hue of the water-soluble dye and causes the water-soluble dye to precipitate. Therefore, among the above-mentioned water-soluble metal salts, compounds exhibiting a pH of 6 or more as an aqueous solution are preferable.

Other preferred compounds include organic amines, organic ammonium salts, low molecular weight organic compounds such as non-volatile organic amines and organic ammonium salts; polyallylamine salts;
Examples include cationic oligomers or polymers such as polyamine sulfonic acid quaternary ammonium salt, polyaminopolyamine/ebiglolhydrin reaction product, and dicyandiamide/formalin condensate.

Suitable organic compounds include oligomers or polymers having primary to tertiary 7-mino groups as described above, or quaternized products thereof, and particularly preferred organic compounds having the following general formula (
Examples include basic oligomers or polymers represented by I) to (m).

(I) CI(GHz- to H-0→mH(
CHt)- (R+, l?, R3 in the above formula is a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group, an alkanol group, an allyl alkyl group, an allyl alkenyl group, X is an acid group, ■ is an integer from 1 to 7, n is an integer from 2 to lO, ) (II) (C)lz-OH*CHt! (21, Rz, and R3 in the above formula are a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group, an alkanol group, an allylalkyl group, an allylalkenyl group, X is an acid group, and n is 5 to 100 ,000 integer) (Ill and I?2 in the above formula are a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group, an alkanol group, an allyl alkyl group, an allyl alkenyl group.

X represents an acid group, and n represents an integer of 5 to too, ooo. ) Compounds represented by general formulas (1) to (III) are.

For example, Nalpoly-607 (manufactured by Nalco Chemical), Polyfix 601 (Iifl Wakobunka Seiken Manufacturer - Cole 1697 (manufactured by Allied Colloid), CatFlohe (manufactured by Calgon Corp), PAS (manufactured by Nittobo), Neofix RPD (manufactured by Calgon Corp), It is commercially available under trade names such as NICCA Chemical Type) and can be suitably used in the present invention.

The base material of the recording material of the present invention having the above-mentioned characteristics can be obtained according to a conventionally known paper manufacturing method. Mainly made from wood pulp, synthetic pulp, synthetic fibers, glass fibers, etc. are used in combination depending on the purpose, and these are used as fillers, sizing agents, various binders, dispersants, water resistance agents, retention improvers, and fluorescent dyes. It can be obtained by blending necessary additives such as and paper-making. Furthermore, when forming a coating layer on the obtained base material, various additives such as those described above may be added to the coating liquid.

In addition, as a method for imparting compounds that precipitate water-soluble dyes to the base material or coating layer, the above-mentioned compounds may be added at the time of paper making, or these compounds may be added to the base material or the coating layer. The coating solution may be adjusted and applied to the surface of the paper after papermaking using any method such as size press method or spray coating method. It only needs to exist 0. For example, if it is added internally during paper making, about 0.1
It is preferable to add it internally at a ratio of ~Log/F11',
Approximately 0.1 to 10 g/ln' when applied to the surface later.
It is preferable to apply the coating at a ratio of 100 to 100%, and the best image density can be achieved with such addition and coating amount.

The recording material of the present invention as described above can be used for fountain pens, felt-tip pens,
It is suitable not only for general writing instruments such as ballpoint pens that use water-based ink, but also as a recording material for inkjet recording that uses water-based ink, and has the following effects.

(1) Because the water-based ink is highly absorbent, the ink will be in the same state as if it were dried immediately after being applied, and even if parts of the recording device or fingers are attached, they may be contaminated or the recorded image may be smeared. There is no.

(2) When used for inkjet recording, the above (
In addition to the effect of 1), the ink dots are nearly perfect circles and have high density, and the dots do not bleed excessively or feather from the dots, making it possible to form clear and high-resolution images.

(3) The base material itself has good ink absorbency and bead shape, so even if the coating layer is relatively thin, the effects of (1) and (2) above are large. There are no problems such as pigment powder falling off due to the thickness, and the texture is similar to that of plain paper, giving it a soft feel.

(4) From the above points, the recording material of the present invention has very good color properties and is suitable for forming color images.

Therefore, the recording material of the present invention is excellent not only as a general recording paper but also particularly as a recording material for inkjet recording. The recording material of the present invention is also useful for thermal transfer paper, wire dot printer paper, electrostatic recording paper, etc., and has excellent versatility.

Next, the present invention will be explained in more detail with reference to Examples, Comparative Examples, and Usage Examples. In addition, parts and percentages in the text are based on weight unless otherwise specified.

Example 1 A raw material pulp was prepared by mixing 85 parts of bleached hardwood kraft pulp (LBKP, Schopper freeness 48°5R) and 15 parts bleached softwood kraft pulp (NBKP, Schopper freeness 54@5R). For this raw material pulp,
20 parts of clay and water resistant agent (PPA-HC1-3L,
0.05 part of Nitto Yukami) was blended and paper was made to obtain a base material having a Steckigt sizing degree of 0 seconds and a filler ash content of 9%.

On the surface of this base material, 10 parts of silica (Syroid, manufactured by Fuji Davison, average particle size 10 μm), 4 parts of polyvinyl alcohol (PVA-117, manufactured by Kuraray), and a water resistance agent (
A coating solution containing 0.5 parts of FAA-HCI-3L (Nitto Yukami) in 100 parts of water was applied by an air knife method to a dry film thickness of 8 pm, and dried to form the recording material of the present invention. Obtained.

Comparative Example 1 Schopper freeness of LBKP and NBKP is 30@S respectively
A recording material of a comparative example was obtained in the same manner as in Example 1 except that R was used. The base material of this recording material had the same Steckigt sizing degree, filler ash content, and the same as those of the recording material of Example 1.

Example 2 After adding 18 parts of calcium carbonate to 100 parts of LBKP (Schopper Freeness 48@5R), a neutral sizing agent (AKD) was added.
(manufactured by Dick Vercules) was added to form a paper to obtain a base material having a Steckigt size degree of 1 second and a filler ash content of 9%.

On the surface of this base material, 1 part of oxidized starch, 0.2 part of common salt, silica (Syroid, manufactured by Fuji Davison, average particle size 151
Lm) 20 parts, polyvinyl alcohol (PVA-11
A coating solution containing 8 parts (manufactured by Ri5Lt) and 0.1 part of a water resistant agent (Polyfix 601, Showa Kobunshi type) in 100 parts of water was coated with a gate roll coating method to achieve a dry film thickness of 3. A recording material of the present invention was obtained by coating the mixture in such a manner that it had a uniform thickness of m and drying.

Comparative Example 2 A recording material of a comparative example was obtained in the same manner as in Example 2 except that the Schopper freeness of LBKF was 30°SR. The base Stekicht sizing degree and filler ash content of this recording material were the same as those of the recording material of Example 2.

Example 3 10 parts of LBKP (Schopper freeness 40°5R) and N
A raw material pulp was prepared by mixing with 90 parts of BKP (Schopper freeness 45@5R). To this raw material pulp, 15 parts of talc, 5 parts of silica, 0.1 part of cationic starch,
Rosin sizing agent o, ooai! lI and sulfate band 0
．． After adding 0.02 parts, paper was made to obtain a base material with a Steckigt size degree of 2 seconds and a filler ash content of 16%.

On the surface of this base material, 2 parts of calcium carbonate, 10 parts of silica (Syroid, manufactured by Fuji Davison, average particle size 8 gm), 1 part of water-catalyzed magnesium, polyvinyl alcohol (PvA
-117, manufactured by Kuraray) 5 parts water resistant agent (PAS-
880, [Made in 3 bundles] A coating solution containing 0.05 parts in 100 parts of water was coated with a coating solution with a dry film thickness of 8 g using the barcode method.
The recording material of the present invention was obtained by coating and drying.

Comparative Example 3 Schopper freeness of LBKP and NBKP is 30°S
A recording material of a comparative example was obtained in the same manner as in Example 3 except that R was used. The Steckigt sizing degree and filler ash content of this recording material were the same as those of the recording material of Example 3.

Example 4 A recording material of the present invention was obtained in the same manner as in Example 2 except that the filler ash content was 3%.

Comparative Example 4 In Example 2, except that the filler ash content was 3%,
Otherwise, a recording material of a comparative example was obtained in the same manner as in Example 2.

Example 5 A recording material of the present invention was obtained in the same manner as in Example 3 except that the rosin size was 0.1 part and the Steckigt sizing was 8 seconds. .

Comparative Example 5 A recording material of a comparative example was obtained in the same manner as in Example 3, except that the rosin sizing agent was changed to 0.1 part and the Steckigt sizing degree was changed to 8 seconds. .

Example of Use For each of the recording materials of Examples 1 to 5 and Comparative Examples 1 to 5, an on-demand inkjet recording head (discharge Inkjet recording was performed using a recording device having an orifice diameter of 80 μm, a piezo vibrator drive voltage of 7°V, and a frequency of 2.6 KHz.

1 part 2 parts (composition) C, 1, Direct Yellow 86 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
68 parts, L2no (composition) G, 1. Acid Red 35 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
68 parts Li21 (composition) C6 [, Direct Blue 86 2v & diethylene glycol 20 parts Polyethylene glycol #200 10 parts water
68 parts Equal U (Composition) C, X, Acid Black 26 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
Evaluation results of the recording materials of the 68-part Example and Comparative Example are shown in Table 1.

Each evaluation item in Table 1 was measured according to the following method.

(1) Ink fixation time was measured by measuring the time required for the ink to dry and stop adhering to the finger when touching the recorded image after recording.

(2) The dot density was calculated using Sakura Microdensidometer PD by applying JISK7505 to the printed microdots.
The black dots were measured using M-5 (manufactured by Konishiroku Photo Industry Co., Ltd.).

(3) To calculate the dot shape coefficient, measure the dot area using an image analysis device, assume a circle with the same area as the dot, calculate its circumference, and calculate the dot's circumference length i. It was measured and calculated using the following formula.

Dot shape factor=L+XIOO/LJ (%)(
4) For the panel test, we created a 1010x20 sample and asked 40 people (24 men, 16 women), "Which one has the best sharpness and contrast test?" and gave 5 points to the best one. One point was given to the worst one, and the total score was shown to give an overall Xt rating.

Li l -.

Ink'7 1 18+ 1 second 1 second 5-A top-1-wata 1.1 1.2 1.3 521 Arashi' mouth [195% 34% 95% A Baseman 22 Ku i5' L Rule 1 second 2 seconds -u 1.0 G, 9 do
/'84% 83% -stop comparison 舊一１上'' constant 10 rainbow 1 second 1 second 2 seconds to'
-t ° 0.7
0.7 0.9 do-, /',
83% 82% 84% Ink d3 seconds 5 seconds -10,70,3 dot 7 72%
75% Paltest 120 125 Patent applicant Canon Corporation'i? 'i-;:

Claims (7)

[Claims] (1) A recording material characterized by being formed by coating a porous pigment on a base material containing pulp having a shopper freeness of 37 to 60°SR. (2) The recording material according to claim (1), which has a shopper freeness of 45 to 60°SR. (3) The recording material according to claim (1), wherein the porous pigment is silica with an average particle diameter of 1 to 20 μm. (4) The recording material according to claim (1), wherein the coating layer has a thickness of 1 to 15 μm. (5) The recording material according to claim (1), wherein the base material contains 6% by weight or more of the filler as ash. (6) The recording material according to claim (1), wherein the base material has a Steckigt sizing degree of 5 seconds or less. (7) The base material and/or the coating layer contains a cationic resin and/or a metal salt (
The recording material described in item 1).