JP2000247016A - Inkjet recording sheet - Google Patents

Abstract

(57) Abstract: Provided is an ink jet recording sheet capable of performing offset printing and having good ink setting properties and image water resistance in a high-speed rotary ink jet system. An alkylamine / epihalohydrin polycondensate and / or an alkylamine / ammonia / epihalohydrin polycondensate having a molecular weight of 20,000 or less, preferably 10,000 or less, is added to a support in an amount of from 1.0 to 1.0 on both sides.
An ink jet recording sheet adhered to 2.0 g / m ² and has a 10-second cobb size according to JIS P8140 of 10 to 30 g / m ² .

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 having good water resistance and the like in an ink jet recording system for recording using a water-soluble ink. More specifically, the present invention relates to a plain paper type ink jet recording sheet which can be used in a high-speed rotary ink jet printing system, which is capable of offset printing, has good ink setting properties in ink jet recording, and has good image water resistance. It is.

[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, and is rapidly spreading in various applications as a recording device for various figures including Chinese characters and color images. Furthermore, the image formed by the multi-color inkjet method is
Compared to multi-color printing by the plate making method or printing by the color photographic method, it is possible to obtain a record comparable to that of the printing by the color photographic method. Further, in applications requiring a small number of copies, since it is cheaper than by photographic technology, it is being widely applied to the field of full-color image recording.

[0003] More recently, a high-speed ink jet printing system of a rotary printing system has also been developed and is being used for on-demand printing such as address printing, customer information printing, numbering printing, and bar code printing. In such applications, it is common to perform offset printing of fixed information in advance and inkjet-print only variable information. A recording sheet that has not only inkjet suitability such as water resistance of an image but also offset printing suitability is required. Have been.

That is, the recording sheet can be subjected to offset printing, and in a rotary type high-speed ink-jet printing system, the recording sheet has sufficient ink setting even at a printing speed of 150 m / min or more, and prints under high humidity conditions or printing conditions. Even when the site is exposed to water for some reason, it is required that the ink dye does not flow out (image water resistance).

[0005] As the form of the ink jet recording sheet, an ink receiving layer is provided on a support such as a paper such as a so-called high quality paper or a bond paper, a paper such as a high quality paper, a synthetic paper, a synthetic resin film or the like. Coated paper type.

[0006] The coated paper type is a low coating amount type in which the coating amount of the ink receiving layer is about 1 to 10 g / m ^{2, and} 10 to 20 g.
/ m ² about intercoat coating amount type, there is a 20 g / m ² or more of each ink jet recording sheet of high coating weight type.

In particular, in recent years, plain paper types have been
It is desirable both in appearance and handling, and has been desired. However, these plain paper type ink jet recording sheets have a lower image density than the coated paper type,
At present, sufficient water resistance of images has not been obtained.

[0008] Several methods have been proposed for improving the water resistance of dyes, for example, JP-A-55-1503.
No. 96 discloses a water-resistant method for forming a dye and a chelate in a water-soluble ink. Further, in order to simultaneously improve the water fastness and light fastness of the dye, JP-A-59-11752 has been proposed.
JP-A-59-1 discloses an example of an ink jet recording sheet containing cationic colloidal silica.
Japanese Patent No. 37652 discloses an example of an ink jet recording sheet containing a basic polyaluminum hydroxide compound, and JP-A-60-11389 discloses an ink jet recording sheet containing a basic oligomer. Is shown.

Japanese Patent Application Laid-Open Nos. Hei 9-202042 and Hei 10-166713 disclose examples of plain paper type ink jet recording sheets in which a cationic resin is adhered to control the size to a low size. I have. When this method is used, the ink setting property and image water resistance in ink jet recording are good, but troubles in offset printing caused by its high ink absorbency (low sizing property) are often seen, and this trouble is avoided. Therefore, it has been found that simply increasing the size of the recording sheet significantly deteriorates the image water resistance.

[0010]

As described above, in the case of a plain paper type ink jet recording sheet, a recording sheet satisfying the suitability of both is not obtained in the offset printing and the rotary printing type high speed ink jet printing system. It is the current situation.

An object of the present invention is to satisfy the following problems in a plain paper type ink jet recording sheet. 1. Offset printing is possible. 2. To have good ink setting properties and image water resistance in a rotary type high-speed inkjet printing system.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above, and as a result, have found that offset printing can be performed by attaching a specific cationic resin to a support and controlling the size to a specific range. An ink jet recording sheet which is possible and has good ink setting property and image water resistance in ink jet recording has been invented.

That is, in the ink jet recording sheet of the present invention, an alkylamine / epihalohydrin polycondensate having a molecular weight of 20,000 or less and / or an alkylamine / ammonia / epihalohydrin polycondensate having a molecular weight of not more than 20,000 is used on both sides of the support. 0 g / m ² and J
10-second cobb size according to IS P8140 is 1
It is characterized by being 0 to 30 g / m ² .

Further preferably, an alkylamine-epihalohydrin polycondensate and / or an alkylamine-epihalohydrin
Ammonia / epihalohydrin polycondensate has a molecular weight of 10
000 or less.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an ink jet recording sheet of the present invention will be described in detail.

In order to improve the image water resistance of a water-soluble ink containing a direct dye or an acidic dye used in an ink jet recording system, fixing of the dye by a reaction between an anionic portion of the dye and a cationic substance and a water-resistant treatment are carried out. Is self-evident. From the viewpoint of improving the image density and image quality (feathering), it is desirable to increase the size of the recording sheet. However, if the size is extremely increased, the ink overflows without being absorbed by the recording sheet. It will never stop being used as an ink jet recording sheet. Further, it has been found that even when the sizing property is applied to such an extent that the ink does not overflow, the water resistance of the image deteriorates with the improvement in the sizing property. It is considered that the reason why the image water resistance deteriorates with the improvement in size is that the dye in the printed ink is more likely to stay on the paper surface, not inside the paper layer.

As a method for imparting image water resistance to an ink jet recording sheet, a method of adhering a cationic resin as described below is usually employed.

The generally used cationic resin is a monomer, oligomer or polymer of a primary to tertiary amine or quaternary ammonium salt which dissociates when dissolved in water to exhibit a cationic property. Or a polymer. In particular, in the present invention, an alkylamine / epihalohydrin polycondensate and / or an alkylamine / ammonia / epihalohydrin polycondensate is used.

The molecular weight of the cationic resin used in the present invention is 20,000 or less, preferably 10,000 or less. When the molecular weight is larger than 20,000, sufficient image water resistance cannot be obtained. The reason for this is not clear, but the inks used in rotary high-speed inkjet printing systems are:
It is an anionic dye having a relatively large molecule, and the fixing mechanism with the cationic resin is presumed to be that a fixing agent adheres around the dye molecule. Therefore, in order to fix the dye efficiently, a lower molecular weight is considered preferable. .

The dry adhesion amount of the cationic resin is from 1.0 to
A range of 2.0 g / m ² is preferable, and if it is less than this range, sufficient image water resistance cannot be obtained, and it may be more than this range, but no further effect of improving image water resistance can be obtained, It is not preferable in terms of cost and apparently far from plain paper.

As a method for attaching the cationic resin, it is also possible to apply the coating with various coating machines such as a size press, a gate roll coater, a film transfer coater, a blade coater, a rod coater, an air knife coater, and a curtain coater. However, from the viewpoint of cost, it is desirable that the adhesive be adhered by a size press, a gate roll coater, a film transfer coater, or the like provided in a paper machine and finished on-machine.

The sizing property of the ink jet recording sheet of the present invention is such that a 10-second cobb size according to JIS P8140 is 10 to 30 g / m ² . The reason for specifying the degree of cobb size is that when the value is large, that is, when the water absorption is good, although the ink setting property and the image water resistance in the ink jet recording are good, it causes trouble in the offset printing. Troubles in offset printing are blank pilling and background dirt.The water absorption is so good that it causes a decrease in the strength of the paper surface. The plate is considered to be dirty because it is robbed. If the supply amount of dampening water is increased in order to avoid contamination, the balance between the printing ink and the water will be lost, resulting in poor ink deposition and the like.

The cob size of 10 seconds is 10 g / m ^2.
In the case where the water absorption is smaller, that is, when the water absorption is poor, 150 m / m
In inkjet recording performed at a printing speed of at least in, the printed ink is not completely dried by the auxiliary drying device, but is transferred to a metal roll provided immediately after the auxiliary drying device, and the transferred ink is re-transferred to paper. And cause dirt.

The control of the 10-second cobb size is as follows:
Internal sizing agents such as rosin sizing agents, alkenyl succinic anhydrides, alkyl ketene dimers, and petroleum resin sizing agents may be used alone, but surface sizing agents can be used in combination with a cationic resin using a size press or gate roll device. Can also be used.

The surface sizing agent used in combination with the cationic resin includes styrene / acrylic acid polymer, styrene /
Surface sizing agents such as methacrylic acid-based polymers, acrylonitrile / vinyl formal / acrylate ester copolymers, styrene / maleic acid-based copolymers, AKD-based, and rosin-based can be used. For this, a cationic surface sizing agent is preferred.

Further, a binder is used if necessary together with the cationic resin and the surface sizing agent.
Use of phosphate esterified starch, self-modified starch, cationized starch or various modified starches, polyethylene oxide, polyacrylamide, sodium polyacrylate, sodium alginate, hydroxymethylcellulose, methylcellulose, polyvinylalcohol or derivatives thereof alone or in combination can do.

Examples of the support of the ink jet recording sheet of the present invention include a paper-like material such as a paper mainly composed of wood fibers or a non-woven fabric mainly composed of wood fibers or synthetic fibers. Is NBKP, L
In addition to BKP, NBSP, LBSP, GP, TMP, etc., used paper pulp is used, and used alone or in combination as needed.

The raw materials for waste paper pulp referred to in the present invention include: top white, ruled white, cream white, card, and the like shown in the waste paper standard quality standard table of the Waste Paper Recycling Promotion Center.
Special white, medium white, imitation, fair white, Kent, white art, special top cut,
Another example is newspaper, magazine, etc. Further specific examples include uncoated computer paper, which is information-related paper,
Printer paper such as thermal paper, pressure-sensitive paper, and OA waste paper such as PPC paper, coated paper such as art paper, coated paper, lightly coated paper, matte paper, or fine paper, color fine, notebook,
Used paper such as stationery, wrapping paper, fancy paper, medium paper, newsprint, paper change, super-hanging paper, imitation paper, pure white roll paper, uncoated paper such as milk carton, etc.
Chemical pulp paper, high-yield pulp-containing paper and the like are used, but are not particularly limited regardless of printing, copying, printing, and non-printing.

As the internal filler used for the support, conventionally known pigments are used as white pigments, and they can be used alone or in combination. Examples thereof include light calcium carbonate, heavy calcium carbonate, kaolin, clay, talc, and the like. Calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, water White inorganic pigments such as magnesium oxide, styrene-based plastic pigments,
Organic pigments such as acrylic plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins.

In the present invention, other additives such as a pigment dispersant, a thickener, a flow improver, an antifoaming agent, a foam inhibitor, a release agent, a foaming agent, a penetrant, 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. to achieve the desired effects of the present invention. It can also be appropriately compounded within a range that does not impair.

In the papermaking method of the present invention, a paper machine known in the papermaking industry, such as a fourdrinier paper machine, a twin wire paper machine, a combination paper machine, a round mesh paper machine, a Yankee paper machine, can be used as appropriate.

The ink jet recording sheet of the present invention can be used not only as an ink jet recording sheet but also as any recording sheet using a liquid ink at the time of recording. For example, a heat-meltable substance, a heat-meltable ink containing a dye or pigment as a main component, coated on a thin support such as a resin film, high-density paper, or synthetic paper, is heated from the back surface, and the ink is heated. Heat transfer recording image-receiving sheet for melting and transferring ink, heat-melting ink for heating and melting into fine droplets, ink jet recording sheet for flight recording, ink jet recording sheet using ink in which oil-soluble dye is dissolved in solvent, light An image-receiving sheet corresponding to a photosensitive pressure-sensitive donor sheet using a microcapsule containing a polymerizable monomer and a colorless or colored dye / pigment is exemplified.

The common feature of these recording sheets is that the ink is in a liquid state at the time of recording. The liquid ink permeates or spreads in the depth direction or the horizontal direction of the ink receiving layer of the recording sheet until it is cured, solidified or fixed. The above-mentioned various recording sheets require absorptivity according to each system, and there is no limitation even if the inkjet recording sheet of the present invention is used as the above-mentioned various recording sheets.

Further, the ink jet recording sheet of the present invention can be used as a recording sheet for heating and fixing an electrophotographic toner widely used in copying machines and printers.

[0035]

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. Further, “parts” and “%” shown in Examples are
Unless indicated otherwise, parts by weight and% by weight are indicated.

<Preparation of Support 1> Freeness 400 mlcs
f), 10 parts of light calcium carbonate (trade name: TP-121, manufactured by Okutama Kogyo Co., Ltd.) and amphoteric starch (trade name: Cato321)
0, Oji National Co., Ltd.) 0.8 parts, sulfate band 0.6
And 0.11 part of an alkyl ketene dimer type sizing agent (trade name: Size Pine K903, manufactured by Arakawa Chemical Co., Ltd.), followed by papermaking with a fourdrinier paper machine to produce a support 1 having a basis weight of 80 g / m ^2. did.

<Preparation of Support 2> A support 2 was prepared in the same manner as the preparation of the support 1, except that the amount of the alkyl ketene dimer type sizing agent of the support 1 was changed to 0.13 part.

<Preparation of Support 3> Support 3 was prepared in the same manner as in preparation of support 1, except that the amount of the alkyl ketene dimer type sizing agent of support 1 was changed to 0.04 part.

Example 1 A dimethylamine / ammonia / epichlorohydrin polycondensate (trade name: Jetfix 31A, molecular weight: 45) was used as a cationic resin on the support 1 prepared above.
00, manufactured by Satoda Kako Co., Ltd.), and 1.5 g / m ^{2 in} terms of dry coating amount, and phosphoric esterified starch (trade name: MS # 4600, manufactured by Nippon Shokuhin Kako Co., Ltd.) in a dry coating amount of 1.5 g / m ^2. Using an on-machine size press device, the ink-jet recording sheet of Example 1 was prepared by performing machine calendering.

Example 2 The cationic resin of Example 1 was replaced with dimethylamine / epichlorohydrin polycondensate (trade name: Jetfix 36)
N, molecular weight 3100, manufactured by Satoda Kako Co., Ltd.), and an inkjet recording sheet of Example 2 was produced in the same manner as in Example 1.

Example 3 The cationic resin of Example 1 was replaced with dimethylamine / epichlorohydrin polycondensate (trade name: AGEFLOC B50).
An ink jet recording sheet of Example 3 was prepared in the same manner as in Example 1 except that LV, molecular weight was 15,000, manufactured by JPN Chemical Company.

Example 4 The procedure of Example 1 was repeated except that the cationic resin used in Example 1 was a dimethylamine / ammonia / epichlorohydrin polycondensate (trade name: Papiogen P-105, molecular weight: 20,000, manufactured by SENKA). Thus, an ink jet recording sheet of Example 4 was produced.

Example 5 The dry adhesion amount of the cationic resin of Example 1 was 1.0 g / m ^2.
An ink jet recording sheet of Example 5 was produced in the same manner as in Example 1 except for the above.

Example 6 An ink jet recording sheet of Example 6 was produced in the same manner as in Example 1 except that the support of Example 1 was changed to Support 2.

Example 7 The ink-jet ink of Example 7 was prepared in the same manner as in Example 1 except that the support of Example 1 was used as the support ² and the dry adhesion amount of the cationic resin was changed to 2.0 g / m ^2. A recording sheet was prepared.

Example 8 An ink jet recording sheet of Example 8 was produced in the same manner as in Example 2 except that the support of Example 2 was changed to Support 2.

Comparative Example 1 The cationic resin of Example 1 was replaced with dimethylamine / epichlorohydrin polycondensate (trade name: AGEFLOC B5).
0, a molecular weight of 30,000, manufactured by JPN Chemical Co., Ltd.), and an inkjet recording sheet of Comparative Example 1 was produced in the same manner as in Example 1.

Comparative Example 2 The procedure of Example 1 was repeated except that the cationic resin used in Example 1 was dimethylamine / ammonia / epichlorohydrin polycondensate (trade name: Papiogen P-104, molecular weight 40000, manufactured by SENKA). Thus, an ink jet recording sheet of Comparative Example 2 was produced.

Comparative Example 3 The ink jet of Comparative Example 3 was carried out in the same manner as in Example 1 except that the support of Example 1 was used as the support ² and the dry adhesion amount of the cationic resin was changed to 0.8 g / m ^2. A recording sheet was prepared.

Comparative Example 4 An ink jet recording sheet of Comparative Example 4 was produced in the same manner as in Example 1 except that the support of Example 1 was changed to Support 3.

Comparative Example 5 The procedure of Example 7 was repeated except that a cationic surface sizing agent (trade name: Bathoplast 265D, manufactured by BASF) was added to the size press solution of Example 7 so that the dry adhesion amount was 0.2 g / m ^2. In the same manner as in Example 7, an inkjet recording sheet of Comparative Example 5 was produced.

The printing speed of the ink jet recording sheets of Examples 1 to 8 and Comparative Examples 1 to 5 was 150 using a Miyakosi offset form rotary press.
m / min, ink used: T & K TOKA UV best cure black and gold red, UV irradiation amount: 8 kW Two images were printed on an evaluation image mainly composed of ruled lines, halftone dots, and characters. At the time of printing, conditions were set using general form paper, and after confirming that printing was possible without any problem, printing was performed at 6000 m on the sheet.

Next, the paper on which offset printing has been performed is converted to a high-speed inkjet printing system sc manufactured by Miyakoshi.
Printing speed: 50, 100, 15 with item 6240
0, each speed of 200 m / min, ink used: Cytex 1007 black ink, auxiliary dryer: high frequency dryer manufactured by Fuji Denki Koki (transmission frequency 27.12 MHz, output 7.
(5 kW) An evaluation image was printed under the conditions of two passes, and evaluated by the following evaluation method. The results are shown in Table 1.

<Appropriateness of Offset Printing> Visual determination was made on the state of blank piling after offset printing and the state of background stain on blank white paper. A shows good characteristics, B shows good results in practically acceptable range, C shows practical problems, and D shows poor characteristics.

<Ink Setability> Ink-jet recording was performed by changing the printing speed, and the ink was recorded at the upper limit speed at which no transfer stain of the ink occurred. Practically, 150 m / min or more is required.

<Image Water Resistance> The sheet after ink jet recording was immersed in tap water for 30 seconds, and excess water was sucked off with a filter paper and air-dried. Thereafter, the degree of bleeding of the recorded image was visually evaluated. As evaluation criteria, A shows good characteristics, B shows good results in practically acceptable range, C shows practical problems, and D shows poor characteristics.

[0057]

[Table 1]

As is evident from the results of Examples 1 to 8 in Table 1 above, the alkylamine / epihalohydrin polycondensate and / or the alkylamine / ammonia / epihalohydrin having a molecular weight of 20,000 or less, preferably 10,000 or less on the support. 1.0 ~
2.0 g / m ² and 10 second cobb size
The ink jet recording sheet having 30 g / m ² has good suitability for offset printing, and also has good ink setting properties and image water resistance.

Further, as is apparent from Comparative Examples 1 to 3, those having a molecular weight of the alkylamine-epihalohydrin polycondensate and / or the alkylamine-ammonia-epihalohydrin polycondensate of more than 20,000 or the amount of the cationic resin adhered Is less than 1.0 g / m ² , the image water resistance is poor. Furthermore, as is apparent from Comparative Examples 4 and 5, those having a 10-second cobb size degree of more than 30 g / m ² have poor suitability for offset printing, and those having a cob size degree of less than 10 g / m ² have poor ink setting properties. Understand.

[0060]

The ink jet recording sheet of the present invention is
The support has a molecular weight of 20,000 or less, preferably 1000
0 or less of an alkylamine / epihalohydrin polycondensate and / or an alkylamine / ammonia / epihalohydrin polycondensate of 1.0 to 2.0 g / m ² on each side.
By adhering and setting the 10-second cobb size according to JIS P8140 to 10 to 30 g / m ² , the suitability for offset printing is good, and the ink setting property and image water resistance of the rotary type high-speed inkjet printing system are improved. It is a good ink jet recording sheet.

Claims (2)

[Claims] 1. A sheet for use in a high-speed rotary ink jet system, wherein a support is provided with an alkylamine / epihalohydrin polycondensate having a molecular weight of 20,000 or less and / or an alkylamine / ammonia / epihalohydrin polycondensate on both sides. An ink jet recording sheet having 0 to 2.0 g / m ² adhered thereto and having a 10-second cob size according to JIS P8140 of 10 to 30 g / m ² . 2. The ink jet recording sheet according to claim 1, wherein the molecular weight of the alkylamine / epihalohydrin polycondensate and / or the alkylamine / ammonia / epihalohydrin polycondensate is 10,000 or less.