JP2011104785A - Inkjet card form - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel card form which is made from raw paper having opacity, interlaminar strength, rigidity and repulsive force, is little wrinkled when bent, is given an inkjet printing aptitude and can be adapted to on-demand production. <P>SOLUTION: In the inkjet card form, starch is contained in each space between layers of multilayer making base paper consisting essentially of wood pulp fiber, each of both surfaces is a size press-processed surface and has an ink receiving layer thereon, each of front and rear layers is a white layer containing a filler and a middle layer is a shielding layer containing a colorant. The front and rear layers contain a paper strengthening agent and the middle layer contains a Hofmann paper strengthening agent. Application amount of a size press liquid is 3 g/m<SP>2</SP>or more per one side when calculated in terms of solid. The ink receiving layer contains porous synthetic silica pigment, poly(vinyl alcohol) and ethylene vinyl acetate and dry application amount is 15 g/m<SP>2</SP>or more per one side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a card paper including a collection card or a trading card for a game use which is a product comparable to a paper playing card, bromide, or card-type photo book, and relates to a card paper having ink jet printing suitability.

  Card paper is roughly classified into plastic and paper, but paper is superior in terms of manufacturing cost and ease of disposal after use.

  Conventionally, as a paper card paper manufacturing method, base paper making, single-side coating, single-side coated non-coated surfaces are bonded with a laminator, and then cut, offset printing, embossing Post-processing such as varnishing is performed.

  There are a wide variety of card applications, but for entertainment applications, for example, for cards. Cards for playing cards, whether for toys or competitions, have high opacity without print or print show-through required for games such as banning, poker, nervous breakdown, etc. Appropriate rigidity and repulsive force required for games such as speed are required. If it doesn't seem to be bent and restored, it becomes a landmark and can even interfere with the game. Similar to the card game, there are various card games such as Carta, Paper Mahjong, Hanafuda.

  In recent years, collection-type cards with characters and characters printed, and battle-type games using trading cards have become popular, and there are card fortune-telling with tarot cards. There is a growing demand for cards with original demand images printed on them.

The quality required for card paper includes the following characteristics.
1. Appropriate stiffness and repulsive force (sensory, high restitution coefficient and vibration damping ratio).
2. Bending aptitude (both vertical and horizontal).
3. High opacity.
4). Various printability.
5). There should be no paper edges or curls.
6). Good surface skin.
7). There should be no impurities.

  Techniques for solving the problem of creases in card paper having a thickness of 0.3 mm or less are disclosed (for example, see Patent Documents 1, 2, or 3). In Patent Document 1, the middle layer of the base paper has hot water-soluble resin and / or thermoplastic resin fibers and pulp, and at least the surface of the resin fibers melts and the pulp fibers are bonded to each other. It has been proposed to reduce the occurrence of creases by making it present in

In Patent Document 2, the surface layer and the back layer of a multi-layer base paper are composed of a white layer blended with cotton linter pulp, the middle layer is composed of an anko layer colored with a colorant, and the beating degree of the middle layer pulp raw material is Canadian standard drainage. It is less than 300 ml at a degree, and 10 to 30 g / m ^{2 of} both sides are coated with a pigment-containing coating solution based on styrene butadiene latex on both sides of the base paper, and the occurrence of creases is caused by applying a calender treatment. An integrated production system to reduce the number has been proposed.

  Patent Document 3 proposes an ink jet recording sheet that exhibits a sufficient print density and ink jet suitability without losing the unique appearance of the woven fabric.

Japanese Patent Laid-Open No. 09-158097 JP 2004-238748 A JP 2001-39018 A

  The conventional paper card paper manufacturing methods have problems such as a large number of processes and high production costs. In addition, since the manufacturing method is intended to apply offset printing, it is suitable for mass production and mass consumption. On the other hand, in the market, there is an increasing demand for cards that include current designs that reflect the times, but most of the conventional cards have a uniform design. At present, a card manufacturing method suitable for an on-demand type for personal use has not been established based on the concept of creating as much as necessary when a design that suits the personal taste is required.

  Ink jet printing is suitable for small lot printing because it does not use a printing plate. Recently, as the resolution of inkjet printers has increased, high-quality printing has become possible and has attracted attention as a printing method that can meet market demands.

The required quality of the paper for inkjet printing includes the following characteristics.
1. Excellent absorbability of inkjet ink.
2. Excellent light resistance and water resistance of inkjet ink.
3. High density of ink jet printing and excellent ink color reproducibility.
4). The coating layer strength on the inkjet printing surface is relatively strong.

  The technique described in Patent Document 1 is an invention relating to card base paper, and is not a card paper compatible with inkjet printing. And there exists a problem that there are many process steps and production cost starts. Further, there is no description of a manufacturing method with personal use or small-lot production in mind, and this is a concept different from on-demand type manufacturing.

  The technique described in Patent Document 2 includes cotton linter pulp (non-wood pulp), and is expensive compared to wood pulp alone as in the present invention. Furthermore, since the invention of Patent Document 2 is a product to which offset printing is applied, it requires a large amount of printing and mass production, so a certain amount of paper raw materials and raw paper are required. It is a different concept.

  The technique described in Patent Document 3 is characterized in that the base paper is a laminate of an ink receiving layer, a woven fabric, an adhesive resin layer, and paper, and the base paper is black. Although it is a woven medium to the last, it has been reported that the ink-jet printing density is improved by coloring the paper on the non-ink-jet surface side to black. This is very interesting, but the only target property is printability, and the physical strength and characteristics of the recording sheet are not essential items. This is different from a card paper that requires appropriate rigidity and interlayer strength in addition to inkjet suitability (including show-through), which will be described later. In other words, it is similar to the difference between a paper board where printing aptitude is important and a paperboard that requires post-processing aptitude. Therefore, it is only a reference technique as a medium having ink jet printing suitability.

  The object of the present invention is to provide a base paper with opacity, interlaminar strength, rigidity, repulsive force, and it is difficult to bend when the card is folded, and it is new conscious of on-demand production given ink jet printing suitability Is to provide card paper.

The present inventors have found that the card paper is a multi-layer paper made of wood pulp as a main fiber, and that the above problem can be solved by providing a shielding layer in the middle layer and adding a sizing agent to each layer. Was completed. That is, in the ink jet card paper (first form) according to the present invention, the base paper has wood pulp as a main fiber, a surface layer, a back layer, and two or more intermediate layers between the surface layer and the back layer. A multi-layer base paper having a surface, each interlayer of the base paper contains interlayer starch, the surface of the surface layer and the back layer is a surface-size press-treated surface, and one or more layers of ink receiving on both sides of the base paper An inkjet card paper having a thickness of 0.3 mm or less, wherein the surface layer and the back layer are white layers containing a filler, and at least one of the intermediate layers The above is a shielding layer containing a colorant, the surface layer and the back layer contain a paper strength agent by internal addition, and the middle layer contains a Hoffman paper strength agent by internal addition, The amount of interlayer starch applied between the middle layers is And a 1 g / m ² or more in each layer per solid equivalent, the coating amount of size press liquid in the surface size press treatment is in a solid per side content conversion 3 g / m ² or more, the ink-receiving layer, porous A synthetic silica pigment, polyvinyl alcohol and ethylene vinyl acetate, and the dry coating amount of the ink receiving layer is 15 g / m ² or more per side.

The inkjet card paper (second form) according to the present invention is a three-layer papermaking in which the base paper has wood pulp as a main fiber, and has a surface layer, a back layer, and an intermediate layer between the surface layer and the back layer. It is a base paper, each interlayer of the base paper contains interlayer starch, the surface of the surface layer and the back layer is a surface size press-treated surface, and has one or more ink receiving layers on both sides of the base paper, And the ink jet card paper having a thickness of 0.3 mm or less, wherein the surface layer and the back layer are a white layer containing a filler, and the middle layer is a shielding layer containing a colorant The surface layer and the back layer contain a paper strength agent by internal addition, and the middle layer contains a Hoffman paper strength agent by internal addition, and the amount of the size press liquid applied in the surface size press treatment is , 3 g / m ^{2 in} terms of solid content per side The ink receiving layer contains a porous synthetic silica pigment, polyvinyl alcohol and ethylene vinyl acetate, and the dry coating amount of the ink receiving layer is 15 g / m ² or more per side. And

  In the ink-jet card paper according to the present invention, it is preferable that a paper strength agent is further added to the middle layer by internal addition. Interlaminar strength / rigidity (hereinafter sometimes referred to as peeling / rigidity) can be imparted, and the paper can be made more suitable for cards.

  In the ink-jet card paper according to the present invention, the base paper is six-layer papermaking, and the paper strength agent added internally to the front layer and the back layer is 0.1% by mass or more based on the pulp solid content of each layer. And the paper strength agent internally added to the middle layer is 0.5% by mass or more based on the pulp solid content of each layer of the middle layer, and the Hoffman paper strength agent is based on the pulp solid content of each layer of the middle layer. It is preferable that it is 0.1 mass% or more. Stiffness and repulsive force can be imparted, and the paper can be made more suitable for cards.

  In the ink-jet card sheet according to the present invention, it is preferable that the shielding layer is a middle layer of the middle layer among the middle layers. The color of the shielding layer can be prevented from being seen through the white layer (surface layer and back layer), and printing can be made clearer.

  In the ink-jet card paper according to the present invention, the interlayer starch is preferably adhered between the surface layer, the middle layer, and the back layer by spraying the starch. By attaching the starch in a non-contact manner, the starch is difficult to be impregnated in the paper layer and can be attached in a bulky manner. As a result, the rigidity of the card paper can be increased.

  In the ink jet card paper according to the present invention, the ink receiving layer preferably contains an ink fixing agent. Colorability and water resistance can be imparted to the ink adhered to the ink jet card paper.

In the ink jet card paper according to the present invention, JAPAN TAPPI No. is used as an index of interlayer strength. 18-1: 2000 Paper and paperboard-Internal bond strength test method-Part 1: Internal bond strength measured according to Z-axis direction tensile test method is 627 kN / m ² or more, and an index of stiffness and repulsive force JIS P 8125: 2000 Paper and paperboard-Stiffness test method-Stiffness (Taber) measured according to the Taber stiffness tester method is 7.5 mN · m to 8.5 mN · m in the longitudinal direction and 4.7 N · in the lateral direction. m and 5.7 mN · m or less, and a form in which a show-through of a writing line cannot be confirmed in room light is included.

  The present invention provides a new card that is conscious of on-demand production, in which the base paper is provided with opacity, interlayer strength, rigidity, and repulsive force, is not easily creased when the card is folded, and is further provided with ink jet printing suitability. Paper can be provided.

  Next, the present invention will be described in detail with reference to embodiments, but the present invention is not construed as being limited to these descriptions. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

The inkjet card paper (first form) according to the present embodiment is a case where the base paper is a multilayer base paper having at least four layers having two or more middle layers. That is, the base paper is a multilayer base paper having wood pulp as a main fiber, a surface layer, a back layer, and two or more middle layers between the surface layer and the back layer, and each layer of the base paper is Interlayer starch is contained, the surface of the surface layer and the back layer is a surface size press-treated surface, has one or more ink receiving layers on both sides of the base paper, and has a thickness of 0.3 mm or less An ink jet card paper, wherein the surface layer and the back layer are white layers containing a filler, and at least one of the intermediate layers is a shielding layer containing a colorant, and the surface layer and The back layer contains a paper strength agent by internal addition, and the middle layer contains a Hoffman paper strength agent by internal addition, and the coating amount of the interlayer starch between the middle layer and the middle layer is solid for each layer. 1 g / m ² or more in terms of minutes, and the surface The coating amount of the size press liquid in the size press process is 3 g / m ² or more in terms of solid content per side, the ink receiving layer contains a porous synthetic silica pigment, polyvinyl alcohol and ethylene vinyl acetate, and The dry coating amount of the ink receiving layer is 15 g / m ² or more per side. The first form can be, for example, a six-layer base paper having four middle layers.

  The second form is a case where the base paper is a three-layer base paper with one middle layer. The second form has substantially the same configuration as the first form, but since the middle layer is one layer, the middle layer is a shielding layer having a colorant, and the Hoffman paper strength agent is added internally. Contains. Moreover, there is no prescription | regulation about the application quantity of an intermediate | middle layer-intermediate layer interlayer starch.

In the inkjet card paper according to the present embodiment, JAPAN TAPPI No. The internal bond strength measured according to 18-1: 2000 is 627 kN / m ² or more, and the stiffness (Taber) measured according to JIS P 8125: 2000 is 7.5 mN · m to 8.5 mN · This includes a mode in which the horizontal dimension is 4.7 N · m or more and 5.7 mN · m or less and the show-through of the writing line cannot be confirmed in room light. For example, the internal bond strength is preferably 753 kN / m ² or less.

  Next, the materials used and the manufacturing method of the card paper according to the present embodiment will be described.

  It is preferable to use wood pulp, for example, BKP (bleached kraft pulp) as pulp used for the base paper of card paper. A strength that can withstand ink jet printing on both sides can be realized, and a base paper excellent in printability can be obtained. NBKP (conifer bleached kraft pulp), LBKP (hardwood bleached kraft pulp) and mixtures thereof are preferably used in each layer. Considering the balance with the stiffness of the paper in particular, it is preferable that the use ratio (mass ratio) of NBKP and LBKP is 9: 1 to 1: 9. More preferably, it is 8: 2 to 2: 8, and particularly preferably 6: 4 to 4: 6. Further, the pulp used in the middle layer may be composed of only wood pulp, but may also include recovered pulp (waste paper).

  In this embodiment, the beating degree of the entire pulp of each layer is not limited. However, in consideration of various characteristics such as paper strength, white paper skin, air permeability, rigidity, etc., Canadian standard freeness (JIS) P 8121: 1995 Pulp freeness test method) is preferably adjusted to 500 ml or less of CFS. Preferably, it is 450 ml or more and 500 ml or less of CFS.

  The base paper can be made using a known paper machine such as a long paper machine, a circular paper machine, a twin wire paper machine, a super ultraformer paper machine, etc., and a paper web was formed on the paper machine. Later, it can be obtained by drying. In addition, in this embodiment, it is not limited to the papermaking method of a base paper.

  The surface layer and the back layer are made by adding a filler and a paper strength agent to the wood pulp. The base paper becomes a white layer by containing a filler, and can express a clear printed image. Examples of the filler include clay, talc, kaolin, calcium carbonate, amorphous silica, and titanium dioxide. This embodiment is not limited to the type of filler. Moreover, although the addition amount of a filler is not specifically limited, It is preferable that it is 1.0-4.0 mass parts with respect to 100 mass parts of pulp of each layer. More preferably, it is 2.0-3.0 mass parts. If it is less than 1.0 part by mass, the opacity and whiteness may decrease. On the other hand, when the amount exceeds 4.0 parts by mass, the strength of the base paper may be lowered, and the papermaking wire may be worn quickly. Moreover, you may add various chemical | medical agents, such as a conventionally well-known binder, a sizing agent, a fixing agent, and a yield improving agent, as needed.

  A paper strength agent is added to the surface layer and the back layer as a measure against peeling and rigidity. The paper strength agent is, for example, starch, modified starch, or polyacrylamide. Although the addition rate of a paper strength agent changes with kinds of chemical | medical agent, 0.01-1.00 mass% addition with solid content with respect to a pulp is preferable. More preferably, it is 0.10 to 1.00% by mass, and particularly preferably 0.20 to 0.60% by mass. If it is less than 0.01% by mass, paper strength may not be exhibited. Moreover, when it exceeds 1.00 mass%, a process may become dirty easily and it will become uneconomical when the addition amount effect | action of a paper strength agent is considered.

  The middle layer is made by adding Hoffmann paper strength agent to the wood pulp. The Hoffman paper strength agent is added for the purpose of imparting breakability. The Hoffman paper strength agent is, for example, a polyacrylamide cation-modified product. The addition ratio of the Hoffman paper strength agent is preferably 0.1 to 1.0% by mass with respect to the pulp solid content of each of the middle layers. More preferably, it is 0.2-0.8 mass%, Most preferably, it is 0.2-0.6 mass%. If it is less than 0.1% by mass, it may not be possible to impart the suitability for bending. Moreover, when it exceeds 1.0 mass%, the guide roll etc. which contact a base paper may be soiled in a papermaking process.

  In the middle layer, it is preferable to add a paper strength agent in addition to the Hoffman strength material. Paper strength agent is added as a measure against peeling and stiffness. The paper strength agent is, for example, starch, modified starch, or polyacrylamide. Although the addition rate of a paper strength agent changes with kinds of chemical | medical agent, 0.01-1.00 mass% addition with solid content with respect to the pulp of each layer of a middle layer is preferable. More preferably, it is 0.10 to 1.00% by mass, and particularly preferably 0.20 to 0.60% by mass. If it is less than 0.01% by mass, paper strength may not be exhibited. Moreover, when it exceeds 1.00 mass%, a process may become dirty easily and it will become uneconomical when the addition amount effect | action of a paper strength agent is considered.

  In addition to the Hoffman paper strength agent, the intermediate layer in at least one layer in the first form and the intermediate layer in the second form are made by adding a colorant. When the middle layer is a shielding layer containing a colorant, it is possible to obtain a card paper that does not cause a show-through in which the printed pattern on the back side can be seen through when the card is viewed through. When there are two or more middle layers, the shielding layer is preferably a middle layer of the middle layer. For example, when the middle layer is the second layer, the third layer, the fourth layer, or the fifth layer, the third layer or the fourth layer or both the third layer and the fourth layer are used as the shielding layers. . By doing so, it is possible to prevent the color of the shielding layer from being seen through the white layer (surface layer and back layer), to increase the whiteness of the card surface, and to make a card paper suitable for printing.

  The color of the colorant is preferably blue or black, but is not particularly limited to these colors. As the colorant, a direct dye having a strong affinity for cellulose fibers and a colored pigment having a weak affinity for cellulose fibers but easily fixed with a sulfuric acid band are generally used, but are not particularly limited.

  Examples of the direct dye include polyazo dyes, thiazole monoazo dyes, phthalocyanine-based and dioxazine-based organic pigment sulfonated dyes, and basic group-containing dyes (basic direct dyes). Examples of the colored pigment include organic pigments such as phthalocyanine pigments and azo pigments, and inorganic pigments such as oxide pigments and hydroxide pigments. The addition amount of the colorant is not particularly limited as long as no show-through occurs in room light. Particularly preferably, it is 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the middle-layer pulp. More preferably, it is 1.0-2.0 mass parts. Moreover, you may add various chemical | medical agents, such as a conventionally well-known filler, a binder, a sizing agent, a fixing agent, a yield improving agent, to a middle layer as needed.

  In order to add direct dyes and colored pigments to the pulp, they must be dispersed in water in advance and added with pulper, beater, chest, seed box feed pump suction, etc., and mixed well with the stock. A fixing agent such as aluminum sulfate is preferably used for fixing a direct dye or a colored pigment.

Also, interlayer starch is applied between each layer as a measure for peeling and rigidity. As the starch, tapioca starch, acetylated starch, urea phosphorylated starch and the like having a low gelatinization temperature are preferable. The starch concentration applied between the respective layers is preferably 2% by mass or more. Moreover, when there are ^two or more intermediate layers, the starch coating amount between the intermediate layer and the intermediate layer is 1.00 g / m ² or more in terms of solid content. More preferably, it is 1.15 g / m ² or more and 3.00 g / m ² or less. If it is less than 1.00 g / m ² , the strength between layers does not come out, and delamination easily occurs. In particular, in ink jet printing, it may cause end face turning in double-sided printing. Moreover, the suitability for breakage also decreases (becomes easy to break).

  In the ink jet card paper according to the present embodiment, the interlayer starch is preferably adhered between the surface layer, the middle layer, and the back layer by spraying the starch. By attaching the starch in a non-contact manner, the starch is difficult to be impregnated in the paper layer and can be attached in a bulky manner. As a result, the rigidity of the card paper can be increased.

As the paper strength agent for the surface size press treatment, oxidized starch, cationized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide resin and the like are used. Surface sizing agents such as polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, and other resin polymers can also be used. 3.0~5.0g / ^{m 2} on one surface per terms of solid content of paper strength agent in the surface sizing for treatment on both sides a size press, preferably coated in the range of 4.0~4.4g / ^{m 2} . If it is less than 3.0 g / m ² , the rigidity becomes low and the drawback of being easily broken is brought about. Furthermore, generally, if there is no certain size on the base paper side, the print quality in ink jet printing may be impaired. On the other hand, if it exceeds 5.0 g / m ² , not only is it uneconomical, but the paper strength becomes too high, so that the breakability is deteriorated. Furthermore, the water vapor barrier property becomes high, and as a result, the ink jet printing suitability may be inferior.

  The ink receiving layer coating liquid contains a pigment and a binder as main components. The pigment is porous synthetic silica in order to obtain excellent ink jet suitability. However, other pigments can be used as appropriate as long as the ink jet ink has excellent absorbability. In addition, they can be used as appropriate as a simple substance, a composite, or a combination of a plurality of them. Examples of other pigments include synthetic amorphous alumina, light calcium carbonate, calcium silicate, beryl sulfate, diatomaceous earth, urea resin powder, and polystyrene powder.

  As the binder, polyvinyl alcohol and ethylene vinyl acetate are used in combination in consideration of ink jet printing suitability and adhesive performance. However, other binders can be used as appropriate as long as they have excellent ink-jet ink absorbency and adhesive performance. In addition, they can be used as appropriate as a simple substance, a composite, or a combination of a plurality of them. Examples of other binders include modified starch. Although the usage-amount of a binder is based on the pigment to be applied and binder kind, 30-60 mass% is preferable with respect to pigment solid content, More preferably, it is 40-50 mass%. If it is less than 30% by mass, the strength of the coated surface may be weakened. Moreover, when it exceeds 60 mass%, inkjet ink absorptivity may be inferior.

  The ink-receptive layer coating solution includes a dispersant and, if necessary, various aids such as an antifoaming agent, a dye, a water resistance agent, a fluidity modifier, a lubricant, a printability improver, a water retention agent and an antistatic agent. An agent can be added as appropriate. In particular, since the porous synthetic silica does not have a cation site, it is preferable to use an ink fixing agent for the purpose of imparting good ink fixing and color development. Even when alumina having a cation site is applied, the fixability of the ink-jet ink is relatively excellent. However, by using an ink fixing agent, the ink fixing and the color developability can be ensured.

In the ink receiving layer, the ink receiving layer coating liquid may be provided by one-step coating, may be provided by two-step coating, or may be three or more steps. In particular, when the coating amount is increased, two-stage coating is desirable, but in that case, the formulations of the first-stage and second-stage coating liquids are different for the purpose of reducing costs and imparting various functions. Good thing. Moreover, the outermost layer of the coating layer can be appropriately adjusted such as matte tone, dull tone, semi-gloss tone, and gloss tone, but it is essential to have ink jet printing suitability. In particular, for a glossy tone, a fine inorganic pigment or a water-absorbing resin may be applied, and the gloss-imparting layer may be formed on the ink-receiving layer, or the ink-receiving layer and the gloss-imparting layer are combined. Such a coating solution may be applied to the base paper. The dry coating amount of the ink receiving layer coating solution is 15 g / m ² or more per side in consideration of ink jet printing suitability. More preferably, it is 15 g / m ² or more and 20 g / m ² or less, and particularly preferably 15 g / m ² or more and 18 g / m ² or less. If it is less than 15 g / m ² , not only the printability is inferior, but also the concealability may be lowered.

  The method for applying the ink receiving layer coating liquid is not limited in this embodiment. It is coated on both sides of the multilayer paper base by a conventional method using various blade coaters, roll coaters, air knife coaters, bar coaters, and the like, and is dried by any commercially known equipment.

  The outermost layer of the ink receiving layer may be a gloss layer by a cast coating method. As the cast coating method, a known method such as a wet method, a coagulation method, or a rewet method can be selected.

  Thus, the coated paper coated with the ink receiving layer coating solution may be subjected to a calendering treatment on the surface. The calendar process can be processed by known processes such as a super calender, raster press, high temperature soft nip calender, and other general processing means (cutter cutting, guillotine cutting, punching, various cutting processes, etc.) Are applicable. In addition, embossing can be applied as appropriate as fine processing of the surface. The coated paper can be processed into an arbitrary size and shape after inkjet printing.

As the card paper, it is suitable that the basis weight is 270 to 350 g / m ² and the thickness is 0.27 to 0.30 mm. The basis weight is preferably 280 to 340 g / m ² , and more preferably 290 to 330 g / m ² . The thickness is preferably 0.28 to 0.30 mm, and more preferably 0.29 to 0.30 mm.

  Hereinafter, a specific configuration of the card paper of the present invention will be described based on examples. The present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% display in an Example and a comparative example show a mass part (solid content conversion) or mass% (solid content conversion). In addition, all examples and comparative examples were subjected to a paper quality test after being pretreated according to JIS P 8111: 1998 paper, paperboard and pulp-standard conditions for humidity conditioning and testing.

Example 1
(1) Base paper making The base paper has six layers in which a first layer (surface layer), a sixth layer (back layer), and a second layer to a fifth layer (middle layer) are provided between the first layer and the sixth layer. The paper was made. The blending mass ratio of the raw material pulp used for each layer is as follows. The first layer (surface layer) and the sixth layer (back layer) were set to LBKP / NBKP = 90/10, and the second to fifth layers (middle layers) were set to LBKP / NBKP = 100/0. The first and second layers of the raw material have a beating degree of CSF 440 ml, the third and fourth layers have a beating degree of CSF 490 ml, the fifth and sixth layers have a beating degree of CSF 450 ml, and are contained in the first and sixth layers. As a supplement, talc (made by Nippon Talc Co., Ltd .: trade name talc PU) is 5% of pulp, and paper strength enhancer (made by Seiko PMC Co., Ltd .: trade name DS4701, modified polyacrylamide resin) is the first and sixth layers (front and back layers). ) For pulp 0.25%, second, third, fourth and fifth layers (middle layer) 0.6% for pulp, Hoffman paper strength agent (trade name DH4162, manufactured by Seiko PMC, polyacrylamide cation modified) Product) in the middle layer with 0.2% pulp, and sulfuric acid bands with the first and sixth layers (front and back layers) 0.5% pulp, second, third, fourth and fifth layers (middle layer) Pulp 0.3% was added.

  In addition, a black dye (manufactured by Nippon Chemical Industry Co., Ltd .: trade name Direct Paper Black DXL, azo direct dye) dispersed in water at a dispersion concentration of 50% is used as a raw material for the third and fourth layers (middle layers). Part was added.

Then, starch (manufactured by Nippon Shokuhin Kako Co., Ltd .: trade name MS5300, acetate starch starch) was sprayed between the respective layers. The spray concentration of the first, second and fifth to sixth layers (surface layer-intermediate layer, intermediate layer-back layer) is 2%, the solid content spray amount is 0.42 g / m ² , and the second to third The spray concentration of the third to fourth and fourth to fifth layers (intermediate layer to middle layer) was 5%, and the solid content spray amount was 1.15 g / m ² .

(2) Preparation of size press solution The size press solution is composed of 5.5 parts of oxidized starch (Nippon Cornstarch Co., Ltd .: trade name SK-20, 19% concentration) and paper strength agent (Seiko PMC Co., Ltd .: trade name ST-). (5000, modified polyacrylamide resin 30% concentration) was mixed with 5.5 parts and adjusted with industrial water to a solid content concentration of 20%.

(3) Size press treatment In a size press, a size press solution having a concentration of 11% is applied to both sides so as to be 4.4 g / m ² (solid content) on one side, and the first and sixth layers (front and back layers) have a basis weight. 6-layer base paper was made so that each had a grammage of 58 g / m ² and a basis weight of the second to fifth layers (all middle layers) of 126 g / m ² .

(4) Preparation of ink-receiving layer coating solution First, a pigment dispersion was prepared, and then a binder was added to the pigment dispersion to prepare an ink-receiving layer coating solution. The pigment dispersion is composed of 100 parts of synthetic silica (produced by Grace Devison: trade name Psyroid 74X5500), 0.12 part of a dispersant (made by Toa Gosei Co., Ltd .: trade name Aron T-50, 40% concentration product), and defoaming 0.24 part of an agent (manufactured by Toho Chemical Industry Co., Ltd .: trade name Pronal C-205, undiluted solution) was mixed and adjusted with industrial water to a dispersion concentration of 20%. For 100 parts of the pigment dispersion (20% concentration), 20 parts of polyvinyl alcohol (manufactured by Kuraray Co., Ltd .: trade name POVAL PVA-117) and ethylene vinyl acetate (manufactured by Showa Polymer Co., Ltd .: trade name POLYSOL EVA AD-) are used as binders. 6) 40 parts and a cationic polymer (trade name: Papiogen P-105, dimethylamine ammonia epochlorohydrin polycondensate) manufactured by Senka Co., Ltd. as an ink fixing agent are mixed, and the solid content concentration is adjusted with industrial water. The ink-receiving layer coating solution was obtained at 20%.

(5) Formation of Ink Receiving Layer Both sides of the ink receiving layer coating solution were applied with an air knife coater at a dry coating amount of 15 g / m ² per side. The coated paper was calendered and smoothed by a calendar device comprising a metal roll and an elastic roll to obtain a card paper having a paper thickness of 0.273 mm and a basis weight of 272 g / m ² .

(Example 2)
(1) Base paper making The base paper is a first layer (surface layer), a third layer (back layer), and a third layer paper making a second layer (middle layer) between the first layer and the third layer. did. The blending ratio of the raw material pulp used for each layer is as follows. The first layer (surface layer) and the third layer (back layer) were LBKP / NBKP = 90/10, and the second layer (middle layer) was LBKP / NBKP100 / 0. The beating degree of the first layer of the raw material is CSF 440 ml, the beating degree of the second layer is CSF 490 ml, the beating degree of the third layer is CSF 450 ml, and talc (manufactured by Nippon Talc Co., Ltd.) is used as an internal filler in the first and third layers. : Trade name talc PU) 5% pulp, paper strength enhancer (product name: DS4701, modified polyacrylamide resin) 0.25% pulp to the first and third layers (front and back layers), 0.6% pulp to the second layer (middle layer), Hoffman paper strength agent (trade name DH4162, manufactured by Seiko PMC, polyacrylamide cation modified product) 0.2% pulp to the second layer (middle layer), sulfuric acid Bands were added to the first and third layers (front and back layers) at 0.5% to pulp and to the second layer (middle layer) at 0.3% to pulp.

  In addition, 2 parts of black dye (manufactured by Nippon Chemical Industry Co., Ltd .: trade name Direct Paper Black DXL, azo direct dye) dispersed in water at a dispersion concentration of 50% was added to the raw material of the second layer (middle layer). .

Then, starch (manufactured by Nippon Shokuhin Kako Co., Ltd .: trade name MS5300, acetate starch starch) was sprayed between the respective layers. The spray concentration between each layer was 2%, and the solid content spray amount was 0.42 g / m ² .

(2) Adjustment of size press solution The size press solution consists of 5.5 parts of oxidized starch (Nippon Cornstarch Co., Ltd .: trade name SK-20, 19% concentration) and a paper strength agent (Seiko PMC Co., Ltd .: trade name ST-). (5000, modified polyacrylamide resin 30% concentration) was mixed with 5.5 parts and adjusted with industrial water to a solid content concentration of 20%.

(3) Size press treatment In a size press, a size press solution having a concentration of 11% is applied to both sides so as to be 4.4 g / m ² (solid content) on each side, and the first and third layers (front and back layers) have a basis weight. Was made into a three-layer base paper so that the weight of each layer was 58 g / m ² and the basis weight of the second layer (middle layer) was 126 g / m ² .

The step of preparing the ink receiving layer coating solution and the step of forming the ink receiving layer were the same as in Example 1. A card paper having a paper thickness of 0.272 mm and a basis weight of 270 g / m ² was used.

(Example 3)
Except for paper making of 6-layer base paper with the basis weight of the first and sixth layers (front and back layers) being 51 g / m ² and the basis weight of the second to fifth layers (all middle layers) being 140 g / m ² Performed as in Example 1.

Example 4
The same procedure as in Example 1 was performed except that the blending ratio of the pulp of the first layer (surface layer), the second layer to the fifth layer (middle layer), and the sixth layer (back layer) was LBKP / NBKP = 95/5. .

(Example 5)
The blending ratio of the pulp of the first layer (surface layer) and the sixth layer (back layer) is LBKP / NBKP = 95/5, the second layer (middle layer), the fifth layer (middle layer) is LBKP = 100, The same operation as in Example 1 was conducted except that the third layer (middle layer) and the fourth layer (middle layer) were LBKP / recovered pulp = 20/80.

(Example 6)
No paper strength enhancer was added to the second, third, fourth, and fifth layers (middle layers), and Hoffman paper strength agent (manufactured by Seiko PMC: trade name DH4162, polyacrylamide cation-modified product) The same operation as in Example 1 was carried out except that 8% was added.

(Comparative Example 1)
The same procedure as in Example 1 was performed except that no paper strength agent was added to each layer.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that no Hoffman paper strength agent was added to the middle layer.

(Comparative Example 3)
The same procedure as in Example 1 was performed except that the amount of starch applied between each layer was 0.5 g / m ² .

(Comparative Example 4)
The same procedure as in Example 1 was performed except that the amount of the size press solution applied was 2.5 g / m ² by a size press.

(Comparative Example 5)
The same procedure as in Example 1 was conducted except that the ink-receiving layer coating solution was a dry coating amount of 14 g / m ² per side.

(Comparative Example 6)
The same procedure as in Example 1 was carried out except that the ink-receiving layer coating solution to be coated on both sides of the base paper was changed to a pigment-containing coating solution based on styrene-butadiene latex, and coating was performed with a blade coater. It was. Next, the formulation content of the ink receiving layer coating solution is shown. The pigment dispersion is composed of 100 parts of kaolin (Mitsubishi Corporation: trade name Amazon SB), 0.12 part of a dispersant (trade name Aron T-50, 40% concentration product manufactured by Toa Gosei Co., Ltd.), and an antifoaming agent (Toho). Chemical Industry Co., Ltd .: trade name Pronal C-205, stock solution) 0.24 part was mixed and adjusted with industrial water to a dispersion concentration of 73%. 25.59 parts of the obtained pigment dispersion (73% concentration), 4.5 parts of titanium oxide (manufactured by Furukawa Chemical Co., Ltd .: trade name FA-PD) and heavy calcium carbonate (manufactured by Imerizu Minerals Japan Co., Ltd .: merchandise) 70 parts of name Cb-95), 14.7 parts of SBR latex (product name: Asahi Kasei Co., Ltd .: trade name L-1432, 48% concentration product) and starch (product name: MS-4600, made by Nippon Shokuhin Kako Co., Ltd.) 1 part concentration product) 0.3 parts were mixed, and the dispersion concentration was adjusted to 60% with industrial water to obtain a coating liquid for ink receiving layer. The ink receiving layer coating solution was coated on both sides with a blade coater at a coating rate of 15 g / m ² per side. The coated paper was calendered and smoothed by a calendar device comprising a metal roll and an elastic roll to obtain a card paper having a paper thickness of 0.270 mm and a basis weight of 272 g / m ² .

(Comparative Example 7)
The same procedure as in Example 1 was performed except that the ink receiving layer coating solution was not applied to both sides of the base paper.

(Comparative Example 8)
The same operation as in Example 1 was performed except that the black dye was not added to the raw materials of the third and fourth layers (middle layers).

  The card paper thus obtained was evaluated for the physical properties of the card paper by the following methods, and the results are shown in Table 1.

[Blank paper property evaluation]
The physical properties of the blank paper were subjected to a paper quality test in accordance with JIS and the following method after pretreatment according to JIS P8111.
(1) Basis weight: JIS P 8124: 1998 Paper and paperboard-Basis weight measuring method.
(2) Thickness: JIS P 8118: 1998 Paper and paperboard-Test methods for thickness and density.
(3) Opacity: After writing an image line on the samples of various examples and comparative examples with a commercially available oil-based magic, it was judged whether it was visible from the direction opposite to the writing surface by holding it over a fluorescent lamp.
○ ... not visible (high opacity, practical level).
X: Visible (low opacity, not suitable for practical use).
(4) Internal bond strength: JAPAN TAPPI No. 18-1: 2000 Paper and paperboard-Internal bond strength test method-Part 1: Z-axis direction tensile test method.
(5) Stiffness (Taber): JIS P 8125: 2000 Paper and paperboard-Stiffness test method-Taber stiffness tester method.
(6) Possibility of breakage: When the card was continuously bent until the short sides (T eyes) and the long sides (Y eyes) were in contact with each other, the presence or absence of creases was visually evaluated.
○ ... No wrinkle generation (practical level).
X: generation of wrinkles (not suitable for practical use)

  Although it is about various sensory evaluations, it is an evaluation that assumes actual use cases, and it is a more practical one that can instantaneously and comprehensively judge various elements that cannot be captured by a measuring instrument. For these reasons, sensory evaluation was adopted.

Inkjet printing suitability evaluation was performed as follows.
Using PM900C manufactured by EPSON, solid uniformity and boundary bleeding of a recorded image portion subjected to full color printing were visually evaluated. The judgment criteria are as follows.
○: Good (practical level).
Δ: Slightly poor (not suitable for practical use)
X: Defect (not suitable for practical use)

In all of Examples 1 to 6, the surface layer and the back layer are white layers containing a filler, and at least one of the middle layers is a shielding layer containing a colorant, and the surface layer and the back layer Contains a paper strength agent by internal addition, and the intermediate layer contains a paper strength agent and Hoffman paper strength agent by internal addition, and when there are two or more intermediate layers, the interlayer between the intermediate layer and the intermediate layer The coating amount of starch is 1 g / m ² or more in terms of solid content for each layer, and the application amount of size press liquid in the surface size press treatment is 3 g / m ² or more in terms of solid content per side, The layer contained porous synthetic silica pigment, polyvinyl alcohol and ethylene vinyl acetate, and the dry coating amount of the ink receiving layer was 15 g / m ² or more per side. As a result, we provide card paper with new inkjet printability that can be used for on-demand type small-lot production that does not delaminate, has stiffness and opacity, and is not susceptible to creases that occur when cards are folded. It became possible to do.

  In Comparative Example 1, since no paper strength agent was added to each layer, the internal bond strength and stiffness (Taber) were weak, and as a result, the suitability for bending was not suitable for practical use.

  In Comparative Example 2, since the Hoffman paper strength agent was not added to the middle layer, the internal bond strength and stiffness (Taber) were weak, and as a result, the suitability for folding was not suitable for practical use.

In Comparative Example 3, since the coating amount of the interlayer starch between the middle layer and the middle layer was less than 1 g / m ^{2 in} terms of solid content per each layer, the internal bond strength and stiffness (Taber) were weak, and as a result, it was broken. The aptitude became unsuitable for practical use.

In Comparative Example 4, since the amount of the size press solution applied was less than 3 g / m ^{2 in} terms of solid content per side, the stiffness (Taber) was weak, and as a result, the suitability for folding was not suitable for practical use.

In Comparative Example 5, since the dry coating amount of the ink receiving layer was less than 15 g / m ² per side, the ink jet printing suitability was poor.

  In Comparative Example 6, since the pigment of the ink receiving layer coating liquid was not porous synthetic silica and the binder was not polyvinyl alcohol or ethylene vinyl acetate, ink jet printing suitability was not suitable for practical use.

  In Comparative Example 7, since no ink receiving layer was provided, the ink jet printing suitability was not suitable for practical use.

In Comparative Example 8, since no shielding layer was provided, the show-through of the handwriting line could be confirmed in room light, and the function as card paper was not achieved.

Claims (8)

The base paper is a multi-layer base paper having wood pulp as a main fiber, a surface layer, a back layer, and two or more middle layers between the surface layer and the back layer, and each layer of the base paper has an interlayer starch The surface layer and the back layer are surface-size press-treated surfaces, have one or more ink-receiving layers on both sides of the base paper, and have a thickness of 0.3 mm or less Card paper, wherein the surface layer and the back layer are white layers containing a filler, and at least one of the intermediate layers is a shielding layer containing a colorant, and the surface layer and the back layer The layer contains a paper strength agent by internal addition, and the middle layer contains a Hoffman paper strength agent by internal addition, and the coating amount of the interlayer starch between the middle layer and the middle layer is converted into a solid content for each layer. 1 g / m ² or more, and the surface size pre The application amount of the size press liquid in the surface treatment is 3 g / m ² or more in terms of solid content per side, the ink receiving layer contains a porous synthetic silica pigment, polyvinyl alcohol and ethylene vinyl acetate, and ink An ink jet card paper, wherein the receiving layer has a dry coating amount of 15 g / m ² or more per side. The base paper is a three-layer base paper having wood pulp as a main fiber, a surface layer, a back layer, and an intermediate layer between the surface layer and the back layer, and each layer of the base paper contains interlayer starch. The surface of the surface layer and the back layer is a surface-size press-treated surface, the base paper has one or more ink receiving layers on both sides, and the thickness is 0.3 mm or less. The surface layer and the back layer are white layers containing a filler, the intermediate layer is a shielding layer containing a colorant, and the surface layer and the back layer are internally added with a paper strength agent. And the intermediate layer contains a Hoffman paper strength agent by internal addition, and the amount of the size press liquid applied in the surface size press treatment is 3 g / m ² or more in terms of solid content per side, The ink receiving layer is made of porous synthetic silica pigment, An ink-jet card paper comprising: revinyl alcohol and ethylene vinyl acetate, and an ink receiving layer having a dry coating amount of 15 g / m ² or more per side.   The inkjet card paper according to claim 1 or 2, wherein a paper strength agent is further added to the middle layer by internal addition. The base paper is a six-layer papermaking,
The paper strength agent internally added to the surface layer and the back layer is 0.1% by mass or more based on the pulp solid content of each layer, and the paper strength agent internally added to the middle layer is the pulp solid content of each layer of the middle layer. The Hoffman paper strength agent is 0.1% by mass or more based on the pulp solid content of each of the middle layers. Card paper.   5. The inkjet card paper according to claim 1, wherein the shielding layer is a middle layer of the middle layer.   The ink-jet card paper according to any one of claims 1 to 5, wherein the interlayer starch is adhered to each surface layer, middle layer and back layer by spraying starch.   The inkjet card paper according to claim 1, wherein the ink receiving layer contains an ink fixing agent. JAPAN TAPPI No. The internal bond strength measured according to 18-1: 2000 is 627 kN / m ² or more, and the stiffness (Taber) measured according to JIS P 8125: 2000 is 7.5 mN · m to 8.5 mN · 8 or less and 5.7 mN · m or less, and the show-through of the writing line cannot be confirmed in room light. The card paper for inkjet as described in 2.