JP2013185294A - Multilayered paper containing recycled pulp and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered paper containing recycled pulp, which is hardly yellowed even when being exposed to light such as sunlight and ultraviolet rays, and is produced by recycling resources.SOLUTION: The multilayered paper containing recycled pulp contains 40 mass% or more of recycled pulp in the whole of a base paper. When layers are defined as a surface layer, a back side layer and an intermediate layer that is arranged between the surface layer and the back side layer respectively, (1) the intermediate layer is formed by one or more layers; (2) a blending ratio of recycled pulp in the intermediate layer is 90 mass% or more; (3) a blending ratio of recycled pulp in either the surface layer or the back side layer, or in both layers is 20 mass% or less; (4) a surface of at least either the surface layer or the back side layer is a coated surface formed by applying a treatment liquid containing either an ultraviolet ray absorber or sodium hypophosphite, or containing both of the ultraviolet ray absorber and sodium hypophosphite; and (5) the multilayered paper does not have an inkjet ink-receiving layer.

Description

  TECHNICAL FIELD The present invention relates to a multi-layered paper pulp blended paper containing recycled pulp (waste paper pulp), and in particular, a multi-layer paper having excellent light resistance with little yellowing and discoloration of a white paper surface even when exposed to ultraviolet rays. Related to recycled pulp and paper.

  In the manufacture of paper, the use of waste paper as raw material pulp has been promoted along with an increase in environmental awareness such as recycling or resource saving. In recent years, there is a very high demand for utilization of used paper even in postcard paper and the like, for example, a transport system for postcards containing recycled pulp obtained from used paper as raw pulp has been described (see, for example, Patent Document 1). .)

  In addition, when a large amount of waste paper pulp is blended, the amount of waste on the surface increases due to residual ink contained in the waste paper pulp or dust that cannot be removed. To improve this, 40% by weight or more of waste paper pulp And a method of making the ratio of waste paper on the surface layer to 20% by mass or less as a multi-layer paper making of 3 or more layers (see, for example, Patent Document 2).

JP-A-2005-35224 JP 2010-47894 A

  The used paper pulp used is roughly divided into medium and high quality. High-quality waste paper pulp includes fine white, ruled white, card, imitation, color, Kent, and white art. Examples of medium-sized waste paper pulp include newspapers, magazines, and cardboard. Medium-sized waste paper pulp contains unbleached pulp fibers such as ground wood pulp (GP), refiner ground wood pulp (RGP), and thermomechanical pulp (TMP). Will turn yellow when exposed to sunlight or other light. For this reason, high-quality waste paper pulp is desirable as the recycled waste paper pulp to be blended. However, fluorescent whitening agents are generally used in high-quality waste paper pulp. When exposed to light, fluorescent whitening agents lose their whitening effect due to deterioration, resulting in yellow paper. There is a problem with taste.

  Therefore, an object of the present invention relates to a multilayer paper waste pulp blended paper, and a multilayer paper waste pulp blend paper that has little yellowing and reuses resources even when exposed to light such as sunlight and ultraviolet rays. Is to provide.

  As a result of intensive studies, the present inventors have determined that when the blending ratio of the waste paper pulp in the entire base paper is 40% by mass or more, the base paper is a multi-layer paper, and the waste paper pulp is blended in the intermediate layer as much as possible to form the surface layer and It has been found that the above-mentioned problems can be solved by suppressing the incorporation into the back surface layer and applying either one or both of the ultraviolet absorber and sodium hypophosphite to at least one surface of the surface layer or the back surface layer. The invention has been completed. That is, the multilayer paper used pulp blended paper according to the present invention is a multilayer paper made of three or more layers of base paper, and the ratio of the used paper pulp to the whole of the base paper is 40% by mass or more. In the pulp-blended paper, among the layers of the base paper, a layer disposed on one surface is a surface layer, a layer disposed on the other surface is a back layer, and a layer disposed between the surface layer and the back layer When expressed as an intermediate layer, (1) the intermediate layer is one or more layers, (2) the proportion of waste paper pulp in the intermediate layer is 90% by mass or more, and (3) the surface layer or the back surface The blending ratio of waste paper pulp in one or both of the layers is 20% by mass or less, and (4) at least one surface of the surface layer or the back surface layer is an ultraviolet absorber or hypophosphorous acid Contains one or both of sodium That the treatment liquid is a coating surface coated with, characterized in that no (5) the ink-jet ink receptive layer.

数１において、照射前の前記表面層又は前記裏面層の測定値をＬ^＊ｘ，ａ^＊ｘ，ｂ^＊ｘとし、照射後の前記表面層又は前記裏面層の測定値をＬ^＊，ａ^＊，ｂ^＊とする。
（条件２）
前記表面層又は前記裏面層の一方の表面が塗布面の場合は、該塗布面のΔＥ^＊が２．５以下であり、前記表面層及び前記裏面層の両方の表面が塗布面の場合は、両面のΔＥ^＊が２．５以下である。 In the case of multilayer paper waste paper blended paper according to the present invention, when the xenon arc lamp is irradiated with a light resistance tester according to JIS B 7754: 1991 “Xenon arc lamp light resistance and weather resistance tester”, It is preferable that ΔE ^* obtained in 1 satisfies the condition 2. It can be set as the paper which suppressed yellowing or discoloration.
(Condition 1)
Using a method of calculating from the lightness index L ^* and the perceptual chromaticity index a ^* and b ^* defined in JIS P 8150: 2004 “Paper and paperboard—Method of measuring color (C / 2 °) —diffuse illumination method” ΔE ^* is determined for both the surface layer and the back layer. ΔE ^* is calculated from Equation 1.

In Equation 1, the measured value of the surface layer or the back surface layer before irradiation is L ^* x, a ^* x, b ^* x, and the measured value of the surface layer or the back surface layer after irradiation is L ^* , a ^*. , B ^* .
(Condition 2)
When one surface of the surface layer or the back surface layer is a coated surface, ΔE ^{* of the} coated surface is 2.5 or less, and when both surfaces of the surface layer and the back surface layer are coated surfaces, ΔE ^{* on} both sides is 2.5 or less.

  In the multilayer paper waste paper blended paper according to the present invention, the layer containing waste paper pulp (hereinafter, sometimes referred to as a waste paper pulp blend layer) preferably contains a fluorescence deactivator. Light resistance can be further improved.

  The method for producing a multi-layered waste paper pulp blended paper according to the present invention is a multi-layer paper having a base paper of three or more layers, and the ratio of the waste paper pulp to the whole of the base paper is 40% by mass or more. In the method for producing waste paper pulp-blended paper, among the layers of the base paper, a layer disposed on one surface is a surface layer, a layer disposed on the other surface is a back layer, and between the surface layer and the back layer When each of the arranged layers is expressed as an intermediate layer, the intermediate layer is formed of one or more layers, and the blending ratio of the used paper pulp in the intermediate layer is 90% by mass or more, and either the surface layer or the back layer A base paper preparation step of making the base paper with a blending ratio of waste paper pulp in one or both layers of 20% by mass or less, and at least one surface of the surface layer or the back layer, an ultraviolet absorber or Sodium hypophosphite One or a coating step of coating a treatment solution containing both, have, the multilayer paper making recycled pulp paper is characterized by having no ink-jet ink receiving layer.

  In the method for producing a multi-layer paper waste paper blended paper according to the present invention, the base paper preparation step is preferably a step of making a paper by blending a layer containing the waste paper pulp with a fluorescence deactivator. Light resistance can be further improved.

  The present invention relates to a multilayer paper waste paper blended paper, and provides a multilayer paper waste paper blend paper that has little yellowing and reuses resources even when exposed to light such as sunlight and ultraviolet rays. it can.

  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. In the present embodiment, the form having the inkjet ink receiving layer is a reference form.

  The multi-layered waste paper pulp blending paper according to this embodiment is a multi-layer paper having three or more base papers, and the ratio of the waste paper pulp to the whole base paper is 40% by mass or more. In the paper, among the layers of the base paper, the layer placed on one surface is written as the surface layer, the layer placed on the other surface is written as the back layer, and the layer placed between the surface layer and the back layer is written as the intermediate layer. When (1) the intermediate layer is one or more layers, (2) the proportion of the recycled paper pulp in the intermediate layer is 90% by mass or more, (3) either one or both of the front surface layer and the back surface layer The ratio of the used paper pulp in the layer is 20% by mass or less, and (4) at least one surface of the surface layer or the back layer contains either one or both of an ultraviolet absorber and sodium hypophosphite. (5) Ink It does not have a Ettoinku receiving layer.

Although an ultraviolet absorber is not specifically limited, For example, what is marketed can be selected arbitrarily and used. Examples of the ultraviolet absorber include salicylic acid, benzophenone, and benzotriazole. Examples of the salicylic acid type include phenyl salicylate and pt-butylphenyl salicylate. Examples of the benzophenone series include 2,4-dihydroxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, and 2,2′-dihydroxy-4-methoxybenzophenone. Examples of the benzotriazole system include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-t-butylphenyl) benzotriazole, 2- (2′- Hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2 '-Hydroxy-3', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2 '-[2'-hydroxy-3'-(3 '', 4 '', 5 '', 6 '' -Tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl ) Fenault ]. These may be used individually by 1 type, or may use 2 or more types together. Among these, a benzotriazole type is more preferable in that it has a high effect of absorbing ultraviolet rays and can more effectively suppress yellowing. Furthermore, a copolymer of an ultraviolet absorber and an acrylic resin, a vinyl acetate resin, an ethylene vinyl acetate resin, or the like may be used. Specific examples include “Sun Life UA-20” (manufactured by Nikka Chemical Co., Ltd.), “ "ULS-1383MG", "ULS-1383MA" (manufactured by Yushi Kogyo Co., Ltd.), "Shinguard T-40", "Shineguard W-51" (Senka), "New Coat UVA-101", "New "Coat UVA-102", "New coat UVA-103", "New coat UVA-104", "New coat UVA-204W" (manufactured by Shin-Nakamura Chemical Co., Ltd.). As a specific example, sodium hypophosphite is “ADEKA ARKLES B-1” (manufactured by ADEKA). The coating amount of either one or both of the ultraviolet absorber and sodium hypophosphite is different in light resistance depending on the quality and blending ratio of the used paper pulp, and may be appropriately adjusted according to the desired quality. As high-quality waste paper pulp, when the ratio of waste paper pulp in the entire base paper is 40 to 70% by mass, the mass after drying is 0.05 to 1.50 g / m ² per side. Preferably there is. More preferably 0.075~1.00g / ^{m 2,} particularly preferably 0.10~0.50g / ^{m 2.} Only one or both of the UV absorber and sodium hypophosphite may be applied. When both an ultraviolet absorber and sodium hypophosphite are applied, the coating amount refers to the sum of the dry mass of both. The surface to be applied may be performed in accordance with the desired quality, and may be applied to one side (the surface of either the surface layer or the back layer) or to both sides (the surfaces of both the surface layer and the back layer). Good. Moreover, when apply | coating to both surfaces, it is good also as the chemical | medical agent apply | coated to a surface layer or a back surface layer being the same or different. If the coating amount is less than 0.05 g / m ² , the effect of improving light resistance may be insufficient. When it exceeds 1.50 g / m ² , the improvement effect is not obtained as compared with the coating amount, which is not economical. Also, problems such as dropout may occur in post-processing. In order to improve light resistance more effectively, an ultraviolet absorber or sodium hypophosphite is applied to the surface of the surface layer and / or the back layer. As a result, ultraviolet rays can be blocked on the paper surface, and yellowing and fading of waste paper pulp can be more effectively suppressed. On the other hand, an ultraviolet absorber or sodium hypophosphite is used to form a paper material for forming an intermediate layer, a paper material for forming a surface layer, or a back surface layer in a papermaking process of a multi-layered paper pulp blended paper. When blended directly with paper stock, UV absorbers or sodium hypophosphite is dispersed in the layer containing waste paper pulp, so light such as ultraviolet rays cannot be blocked efficiently on the paper surface. The effect of improving light resistance cannot be obtained effectively. In addition, some of the chemicals blended in the paper stock will not settle in the paper during paper making and will escape into white water, so the amount of UV absorber or sodium hypophosphite must be increased, which is not economical. .

  The average particle diameter of the ultraviolet absorber by the laser diffraction method is preferably 0.1 to 5.0 μm, and more preferably 0.5 to 1.5 μm. The ultraviolet absorber is preferably used after being pulverized so that the average particle diameter is in a desired range. As a grinding method, for example, a sand grinder is used.

  Examples of combinations of the application surface and the drug to be applied include (1) a mode in which an ultraviolet absorber is applied only to the surface layer, (2) a mode in which sodium hypophosphite is applied only to the surface layer, and (3) a surface layer (4) A mode in which an ultraviolet absorber is applied only to the back layer, (5) A mode in which sodium hypophosphite is applied only to the back layer, (6) A back side A mode in which an ultraviolet absorber and sodium hypophosphite are applied only to the layer, (7) A mode in which an ultraviolet absorber is applied to the surface layer and the back layer, and (8) Sodium hypophosphite is applied to the surface layer and the back layer, respectively. (9) A mode in which an ultraviolet absorber and sodium hypophosphite are applied to the surface layer and the back layer, respectively, (10) A mode in which an ultraviolet absorber is applied to the surface layer and sodium hypophosphite is applied to the back layer (11) A mode in which sodium hypophosphite is applied to the surface layer and an ultraviolet absorber is applied to the back surface layer. (12) An ultraviolet absorber and sodium hypophosphite are applied to the surface layer, and an ultraviolet absorber is applied to the back surface layer. It is the form which applies. However, these are merely examples, and the present invention is not limited to these.

  The ultraviolet absorber or sodium hypophosphite is either applied alone using a treatment liquid in which either or both of the ultraviolet absorber and sodium hypophosphite are dispersed in a medium such as water, or further added to the treatment liquid. Or you may mix | blend and apply | coat various additives, or you may mix | blend and apply | coat to the conventionally known surface size liquid. Examples of the coating method include a conventional size press, a gate roll size press, a film transfer size press, an air knife coater, and a rod coater. Moreover, when apply | coating both a ultraviolet absorber and sodium hypophosphite, you may apply | coat both simultaneously or separately. When applying separately, the order of application is not ask | required.

  Moreover, it is good also as application | coating only on one side using a film transfer system size press, an air knife coater, a rod coater etc. according to the quality to request | require.

  The mixing ratio of waste paper pulp in the entire base paper is 40% by mass or more. More preferably, it is 45 mass% or more. When the ratio of the waste paper pulp in the entire base paper is less than 40% by mass, it becomes difficult to achieve the object of the present invention by reusing waste paper, increasing the recycling rate, and reusing resources. The higher the recycled paper pulp content of the entire base paper, the higher the recycling rate of the used paper can be achieved. However, when considering yellowing or light fading due to light such as sunlight or ultraviolet rays, the upper limit of the ratio of the used paper pulp in the entire base paper is preferably 70% by mass, and more preferably 60% by mass. .

  When waste paper pulp is blended uniformly in the front layer, intermediate layer and back layer, or when single-layer paper making, yellowing of the base paper due to light such as sunlight or ultraviolet rays occurs in correlation with the percentage of the waste paper blended pulp. It becomes easy. Furthermore, yellowing is more likely to occur as the proportion of used paper pulp in the front and back layers increases. Therefore, it is preferable that waste paper pulp is blended preferentially in the intermediate layer over the front surface layer and the back surface layer. Therefore, the ratio of the used paper pulp in the intermediate layer is 90% by mass or more. The blending ratio of the waste paper pulp in the intermediate layer is more preferably 100% by mass.

  When the waste paper pulp blending ratio with respect to the entire desired base paper can be achieved by blending the waste paper pulp only in the intermediate layer, it is more preferable not to blend the waste paper pulp in the surface layer and the back surface layer. In postcards, barcodes are printed with colorless and transparent fluorescent dye ink (invisible ink) when passing through the automatic sorting machine on the address side (reading the zip code and address and converting the address information into a barcode) Printing on postcards.) Since most of the used paper in the market uses fluorescent dyes, the bar code cannot be read when used paper containing a large amount of it is on the surface. (Since mail postcards are sorted in the order of delivery) Since it interferes with wastepaper pulp, other than the intermediate layer, and when the intended use is postcards, wastepaper pulp is blended on the address side. Without using, it is preferable to mix waste paper pulp on the surface which becomes the communication surface side.

The waste paper pulp blending ratio is calculated by Equation 2.
(Equation 2) Waste paper pulp blending ratio (%) = used paper pulp blending amount / (virgin pulp blending amount + used paper pulp blending amount) × 100
Also, the detailed definition of waste paper shall be issued by “Recycled Paper Display Method” (April 2, 2008) issued by the Japan Paper Association.

  The waste paper pulp is preferably blended in the intermediate layer as much as possible from the viewpoint of light resistance and fading, and the blending into the front layer and the back layer is preferably suppressed. In order to increase the blending ratio of the used paper pulp in the entire base paper, for example, the ratio of the basis weight of the intermediate layer is increased, and the used paper pulp is preferentially blended in the intermediate layer. For example, when it is desired to set the ratio of waste paper pulp to 50% by mass with respect to the entire base paper, the basis weight ratio of the front surface layer and the back layer is 25% by mass, and the basis weight ratio of the intermediate layer is 50% by mass. By making the total amount of the pulp in the intermediate layer into used paper pulp, it is possible to obtain a used paper pulp blended paper having good light resistance and fading. Also, if you want to further increase the percentage of used paper pulp in the entire base paper, that is, if you do not reach the desired ratio by adding recycled paper pulp only to the intermediate layer, add recycled paper pulp to the front or back layer. can do. In addition, self-rotating paper is generated during production, but it is preferably used in the intermediate layer. If the intermediate layer cannot be consumed, a self-circulating paper can be added to the front layer or the back layer. However, from the viewpoint of light resistance and fading, the blending ratio is 20% by mass or less as the blending ratio of waste paper pulp. More preferably, it is made into 15 mass% or less, Especially preferably, it does not mix | blend.

  The intermediate layer is formed of one or more layers. When two or more intermediate layers are formed, as long as the proportion of the used paper pulp in the entire intermediate layer is 90% by mass, there is no particular limitation on which intermediate layer the used paper pulp is added to. For example, among the intermediate layers, the waste paper pulp may not be blended in the intermediate layer in contact with the front surface layer or the back layer, and the waste paper pulp may be blended only in the intermediate layer not in contact with the front surface layer or the back layer. Waste paper pulp may be blended in all layers. From the viewpoint of light resistance and fading, it is preferable to increase the blending ratio of the used paper pulp of the intermediate layer which is the inner side. Here, the mixing ratio of the used paper pulp in the intermediate layer refers to the mixing ratio of the used paper pulp with respect to the whole of the three layers when the intermediate layer is formed of three layers.

  Waste paper pulp used for the base paper includes, for example, high-quality waste paper pulp and medium-quality waste paper pulp. In this embodiment, it is preferable to use high-quality waste paper pulp from the viewpoint of light resistance. Examples of the high-quality waste paper pulp include pulps prepared from waste paper such as fine white, ruled white, card, imitation, color, Kent, and white art.

  Examples of medium-quality waste paper pulp include pulps prepared from newspapers, magazines, cutting, medium-quality anti-pause, tea imitation, corrugated cardboard, mounts / base cards, cardboard and the like.

  As pulp used for the base paper, in addition to waste paper pulp, for example, virgin pulp (sometimes referred to as fresh pulp), hardwood bleached sulfite pulp (LBSP), hardwood bleached kraft pulp (LBKP), conifer bleached sulfite pulp (NBSP), softwood bleached kraft pulp (NBKP), mechanical pulp (GP, TMP, BCTMP). In addition to wood pulp, non-wood pulp, synthetic pulp, synthetic fiber, or the like may be used as necessary.

  The used paper pulp used in the present embodiment is preferably not only the disaggregation and dust removal treatment, but also used waste paper pulp after each step such as deinking, bleaching, ink dispersion, and washing. In particular, in the case of multilayer papermaking, fine ink may move to another layer when pressure dehydration is performed by a press part after papermaking. Therefore, it is more preferable to install a cleaning device capable of removing fine ink in the used paper processing step and go through the cleaning step by the device.

  In this embodiment, it is preferable that a used paper pulp compounding layer contains a fluorescence quencher. In particular, since the intermediate layer has a high proportion of waste paper pulp, the light resistance can be further improved by containing a fluorescence quencher. Examples of the fluorescence quencher include polyalkylene polyamine / dicarboxylic acid condensate, polyalkylene polyamine / dicarboxylic acid urea condensate, polyalkyl quaternary ammonium salt of polyalkylene polyamine / dicarboxylic acid urea condensate, polyalkylene polyamine / dicarboxylic acid A polyalkyl quaternary ammonium salt of a condensate, a benzenecarboxylic acid amide derivative, or a mixture of two or more thereof. Specific examples of the fluorescence deactivator include “Cartarex 2L Liquid” (manufactured by Clariant Japan) and “OP-603” (manufactured by Yushi Kogyo Co., Ltd.). The blending amount of the fluorescence deactivator varies depending on the fluorescent dye contained in the used paper pulp to be used, and may be adjusted as appropriate.For example, the dry weight of the used paper pulp contained in each layer of the used paper pulp blending layer The content is preferably 0.03 to 3% by mass, and more preferably 0.10 to 1.5% by mass. If it is less than 0.03 mass%, the improvement effect may be small. When it exceeds 3 mass%, there is a problem of waste liquid treatment. A fluorescence quencher is mix | blended with the stock for forming a used paper pulp compounding layer. The reason for adding a fluorescence deactivator to the stock of the intermediate layer is that the fluorescence deactivator forms a complex with the fluorescent dye contained in the waste paper pulp, thereby preventing the molecular structure of the fluorescent dye from reaching the excited state. Because it suppresses yellowing by suppressing fluorescence, light resistance is maintained even if it is applied to the surface layer and the back layer where the waste paper pulp is not blended or the waste paper pulp content is small. This is because it is difficult to obtain an improvement effect.

  The base paper is made in a multilayer of three or more layers by, for example, a long paper machine, a twin wire paper machine, or a circular paper machine. Or you may make a paper by the combination of these paper machines. In this case, a filler, a dispersion aid, a dry paper strength enhancer, a sizing agent, a fixing agent, a pH adjuster, a dye, a colored pigment, and the like can be appropriately added to the paper as necessary. Here, the pulp beating method is a method of mixing beating after mixing fresh pulp and waste paper pulp, or a method of mixing after performing beating single beating of fresh pulp and waste paper pulp separately. But either is fine. Pulp freeness (Canadian standard freeness) (JIS P 8121: 1995 “Pulp Freeness Test Method”) is not particularly limited, but is preferably 230 to 600 ml. More preferably, it is 300-570 ml.

  The base paper is made in a multilayer of 3 or more layers provided with a surface layer, one or more intermediate layers and a back layer. The basis weight of each layer may be equal or different. The form which makes the basic weight of each layer different can also make the basic weight of an intermediate | middle layer relatively larger than the basic weight of a surface layer, and the basic weight of a back surface layer, for example. Furthermore, it is also possible to provide each one surface layer and back layer and two or more intermediate layers.

The basis weight of base paper is not particularly limited, is preferably from 40~650g / ^{m 2,} more preferably 60~600g / ^{m 2.} Multilayer paper making recycled pulp paper, for example, if a postcard paper, the basis weight of base paper is preferably from 150 to 250 g / ^{m 2,} and more preferably 180-220 g / ^{m 2.}

  In the present embodiment, a sizing liquid may be applied to the surface of the surface layer and / or the back surface layer of the base paper made by multi-layered as described above, if necessary. The sizing solution contains known materials such as surface sizing agents such as oxidized starch, self-modified starch, urea-phosphorylated starch, polyacrylamide, and polyvinyl alcohol, pH adjusters, dyes, colored pigments, and optical brighteners. Can be made. Moreover, you may mix | blend a ultraviolet absorber and / or sodium hypophosphite with a size liquid.

  Examples of the size liquid coating method include a conventional size press, a gate roll size press, a film transfer type size press, an air knife coater, and a rod coater.

  Moreover, it is good also as application | coating only on one side using a size transfer of a film transfer system, an air knife coater, a rod coater etc. as needed. When the sizing liquid is applied to only one surface, it is preferably applied to the surface to which the ultraviolet absorber and / or sodium hypophosphite is applied.

数１において、照射前の前記表面層又は前記裏面層の測定値をＬ^＊ｘ，ａ^＊ｘ，ｂ^＊ｘとし、照射後の前記表面層又は前記裏面層の測定値をＬ^＊，ａ^＊，ｂ^＊とする。
（条件２）
前記表面層又は前記裏面層の一方の表面が塗布面の場合は、該塗布面のΔＥ^＊が２．５以下であり、前記表面層及び前記裏面層の両方の表面が塗布面の場合は、両面のΔＥ^＊が２．５以下である。 In the multilayer papermaking pulp-mixed paper according to the present embodiment, the environment in the test tank is 40 ° C. in a light resistance tester according to JIS B 7754: 1991 “Xenon arc lamp type light resistance and weather resistance tester”. 50% R.D. H. When a xenon arc lamp is irradiated for 10 hours under a condition of a black standard temperature of 63 ° C. and a wavelength of 340 nm and an illuminance of 0.5 w / m ^{2 on} a test piece of multi-layered waste paper pulp blending paper, after irradiation and before irradiation It is preferable that ΔE ^* obtained in condition 1 for the test piece satisfies the condition 2.
(Condition 1)
Using a method of calculating from the lightness index L ^* and the perceptual chromaticity index a ^* and b ^* defined in JIS P 8150: 2004 “Paper and paperboard—Method of measuring color (C / 2 °) —diffuse illumination method” ΔE ^* is determined for both the surface layer and the back layer. ΔE ^* is calculated from Equation 1.

In Equation 1, the measured value of the surface layer or the back surface layer before irradiation is L ^* x, a ^* x, b ^* x, and the measured value of the surface layer or the back surface layer after irradiation is L ^* , a ^*. , B ^* .
(Condition 2)
When one surface of the surface layer or the back surface layer is a coated surface, ΔE ^{* of the} coated surface is 2.5 or less, and when both surfaces of the surface layer and the back surface layer are coated surfaces, ΔE ^{* on} both sides is 2.5 or less.

ΔE ^* indicates that the smaller the value, the less yellowing (the degree of color change is small) when exposed to light such as sunlight and ultraviolet rays. In this embodiment, ΔE ^* is preferably 2.5 or less, and more preferably 2.0 or less.

  When the multilayer papermaking pulp blended paper according to this embodiment is used as a base paper for ink jet printing, it is preferable to provide an ink jet ink receiving layer on at least one surface. By providing the ink-jet ink receiving layer, it is possible to obtain a high-definition printed image with higher image density. When UV absorber or sodium hypophosphite is applied to only one side of the base paper, the inkjet ink receiving layer is formed on the surface where UV absorber or sodium hypophosphite is applied or is not applied It may be formed on top. The ink-jet ink receiving layer is mainly composed of a pigment and an adhesive, and may further contain various auxiliaries. The pigment has a role of absorbing the ink-jet ink, and examples thereof include amorphous synthetic silica, calcium carbonate, clay, talc, titanium oxide, and aluminum hydroxide. These may be used alone or in combination of two or more. In particular, amorphous synthetic silica is preferable in terms of excellent ink absorbability.

  Amorphous synthetic silica is classified into a dry method, a wet method, and a sol method depending on the production method. This embodiment is not limited to the production method, type and shape of amorphous synthetic silica. Two or more kinds of amorphous synthetic silica can be used in combination.

  The adhesive is preferably a water-soluble polymer resin, for example, polyvinyl alcohol derivatives such as polyvinyl alcohol (PVA), carboxy-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, oxidized starch, and grafted starch. Starch derivatives such as, carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, cellulose derivatives such as cellulose sulfate, gelatin, casein, soybean protein, sodium polyacrylate, sodium styrene-maleic anhydride copolymer, sodium polystyrenesulfonate, anhydrous Maleic acid resin. These may be used alone or in combination of two or more. Moreover, you may use together water-soluble polymer and another binder as an adhesive agent. The binder that can be used in combination is preferably a hydrophilic resin. Here, the hydrophilic resin refers to a resin that is easily dispersed in water, and can be used in the form of a dispersion liquid dispersed in water such as an emulsion. Examples of the hydrophilic resin include ethylene-vinyl acetate copolymer (EVA), polyethylene, polyurethane, polyacrylic acid copolymer, polyacrylamide, and styrene-butadiene copolymer. These may be used alone or in combination of two or more. PVA and EVA are preferably used in combination from the standpoints of the absorbability and affinity of the inkjet ink.

  The inkjet ink receiving layer preferably further contains an ink fixing agent in order to improve the fixability and color developability of the inkjet ink. The ink fixing agent contains a cationic polymer as a main component. Examples of the cationic polymer include polyethyleneimine, epichlorohydrin-modified polyalkylamine, polyamine polyamide epichlorohydrin, dimethylamine ammonia epichlorohydrin, polyvinylbenzyltrimethylammonium halide, polydiacryldimethylammonium halide, polydimethylaminoethyl methacrylate hydrochloride, polyvinylpyridium halide. , Cationic polyacrylamide, cationic polystyrene copolymer, diallyldimethylammonium chloride polymer, diallyldimethylammonium chloride sulfur dioxide copolymer, diallyldimethylammonium chloride amide copolymer, dicyandiamide formalin polycondensate, dicyandiamide diethylenetriamine polycondensate , Polyallylamine, poly Allylamine hydrochloride, polyacrylamide resins, polyamide epoxy resins, melamine resins acid colloids, urea-based resins, cation-modified PVA, amino acid type amphoteric surfactants, betaine type compounds, other quaternary ammonium salts, polyamines. These may be used alone or in combination of two or more.

  In addition to pigments and adhesives, inkjet ink receiving layers include dispersants, antifoaming agents, pH adjusters, wetting agents, water retention agents, thickeners, crosslinking agents, mold release agents, preservatives, and softeners as necessary. Various auxiliary agents such as additives, waxes, antistatic agents, antistatic agents, sizing agents, water-proofing agents, plasticizers, fluorescent brighteners, color pigments, coloring dyes, antioxidants, fragrances, deodorants, etc. May be blended.

  When the ultraviolet absorber or sodium hypophosphite is applied in the ink-jet ink receiving layer or on the surface of the ink-jet receiving layer, the absorption of the ink-jet ink is inhibited. Therefore, it is necessary to provide an ink-jet ink receiving layer after applying an ultraviolet absorber or sodium hypophosphite to the surface of the base paper.

  The inkjet ink receiving layer preferably contains 40 to 60 parts by mass of an adhesive with respect to 100 parts by mass of the pigment. More preferably, it is 45-55 mass parts. If it is less than 40 mass parts, the intensity | strength of the coating layer of a receiving layer may become weak. If it exceeds 60 parts by mass, the ink absorbability may be inferior.

The ink-jet ink receiving layer can be formed by coating and drying an ink-jet ink receiving layer-forming coating liquid containing a pigment and an adhesive on multilayer paper and used paper pulp blended paper. The coating amount of the inkjet ink receiving layer is preferably ³ to 15 g / m ² per side in terms of mass after drying. More preferably 5~13g / ^{m 2,} particularly preferably 7~11g / ^{m 2.} If it is less than 3 g / m ² , effective ink jet printer printability may not be obtained. When it exceeds 15 g / m ² , the effect of improving the ink-jet ink absorbency is small as compared with the coating amount, which is not economical and may cause problems such as dropping of the coating layer during post-processing.

  The coating liquid for forming the inkjet ink receiving layer can be applied by a general coater such as an air knife coater, roll coater, blade coater, rod blade coater, bar coater, or die coater. The present embodiment is not limited to this.

  Examples of the drying method after coating include hot air drying, infrared drying, and drum drying, but are not particularly limited in the present embodiment.

  Ink-jet multilayer papermaking pulp blended paper provided with an ink-jet ink receiving layer may be subjected to a calendering treatment as necessary for the purpose of controlling smoothness. Examples of the calendar include a super calendar, a machine calendar, and a soft calendar, but this method is not particularly limited. Further, post-processing treatments according to various product appearances such as embossing, drilling, and back surface tacking may be performed.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%”, respectively, unless otherwise specified. The number of added parts is a value in terms of solid content.

Example 1
<Preparation of base paper A>
100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of unbattered fine quality old paper pulp (freeness 500 ml), and 100 parts of hardwood bleached kraft pulp (freeness) 500 ml), 1.0 part of cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) common to the surface layer, intermediate layer and back surface layer for each pulp raw material, acidic rosin sizing agent (AL1212, Starlight PMC) 0.1 part) and 1.0 part of liquid sulfuric acid band, and talc (NTL, manufactured by Nippon Talc Co., Ltd.) is added and adjusted so that the ash content is 5%. And made paper. These stock, paper making at each length paper machine, 52.5 g / ^{m 2} basis weight of the surface layer, a 75 g / ^{m 2} basis weight of the intermediate layer, the basis weight of the back layer 52.5 g / As m ² , three layers were combined to produce a base paper A having a basis weight of 180 g / m ^{2 for} the entire base paper.

<Preparation of UV absorber dispersion A>
As an ultraviolet absorber, 100 parts of benzotriazole ultraviolet absorber (Adeka Stub DN-41, manufactured by ADEKA) and 17.5 parts of polyvinyl alcohol (PVA205SB, manufactured by Kuraray Co., Ltd.) are blended, and mixed and stirred. % Dispersion was prepared. This dispersion was pulverized with a sand grinder until the average particle size became 0.8 μm to obtain an ultraviolet absorbent dispersion A.

<Application of UV absorber>
A solution obtained by diluting the ultraviolet absorbent dispersion A with water so that the concentration of the benzotriazole ultraviolet absorbent (Adeka Stub DN-41, manufactured by ADEKA) is 5% (hereinafter referred to as 5% diluted liquid A of the ultraviolet absorbent). ) Was applied to both sides of the base paper A and dried so that the mass after drying was 0.4 g / m ² per side to obtain a multi-layered waste paper pulp blended paper A.

(Example 2)
A dispersion containing 20% of a benzotriazole-based ultraviolet absorbent-acrylic resin copolymer (Sunlife UA-20, manufactured by Nikka Chemical Co., Ltd.) as an ultraviolet absorbent was designated as an ultraviolet absorbent dispersion B. A solution obtained by diluting the UV absorbent dispersion B with water so that the concentration of the benzotriazole UV absorber-acrylic resin copolymer (Sunlife UA-20, manufactured by Nikka Chemical Co., Ltd.) is 5% (hereinafter referred to as UV A 5% diluted solution B of the absorbent is applied to both sides of the base paper A and dried so that the weight after drying is 0.4 g / m ² per side. Got.

(Example 3)
100 parts of sodium hypophosphite (Adeka Arcles B-1, manufactured by ADEKA) and 17.5 parts of oxidized starch (MS3800, manufactured by Nippon Shokuhin Kako Co., Ltd.) were blended and mixed and stirred. A dispersion containing 20% sodium phosphate was designated as sodium hypophosphite dispersion A. A solution obtained by diluting sodium hypophosphite dispersion A with water so that the concentration of sodium hypophosphite (Adeka Arcles B-1, manufactured by ADEKA) is 5% (hereinafter, 5% dilute solution of sodium hypophosphite) A)) was applied to both sides of the base paper A and dried so that the mass after drying was 0.4 g / m ² per side to obtain a multilayer paper waste paper blended paper C.

Example 4
<Preparation of base paper B>
Base paper B was prepared in the same manner as base paper A, except that 0.2 part of a fluorescence quencher (Cartarex 2L Rekit, manufactured by Clariant Japan Co.) was further added to the intermediate layer stock. Manufactured.

  In Example 1, except that the base paper A was changed to the base paper B, a multi-layered waste paper pulp blended paper D was obtained in the same manner as in Example 1.

(Example 5)
In Example 2, except that the base paper A was changed to the base paper B, a multi-layered waste paper pulp blended paper E was obtained in the same manner as in Example 2.

(Example 6)
In Example 3, except that the base paper A was changed to the base paper B, a multi-layered waste paper pulp blended paper F was obtained in the same manner as in Example 3.

(Example 7)
In Example 1, the multi-layered waste paper pulp blending paper G was changed in the same manner as in Example 1 except that the coating amount of the 5% diluted solution A of the UV absorber was changed to 0.06 g / m ² in terms of the mass after drying. Got.

(Example 8)
In Example 4, the multi-layered waste paper pulp blended paper H was prepared in the same manner as in Example 4 except that the coating amount of the 5% diluted solution A of the ultraviolet absorber was 0.06 g / m ^{2 in} terms of the mass after drying. Obtained.

Example 9
In Example 3, multi-layered waste paper pulp blended paper I was prepared in the same manner as in Example 3 except that the amount of sodium hypophosphite 5% dilution A applied was 0.06 g / m ^{2 by} weight after drying. Got.

(Example 10)
In Example 6, the multi-layered waste paper pulp blended paper J was used in the same manner as in Example 6 except that the coating amount of the 5% sodium hypophosphite diluent A was 0.06 g / m ² after drying. Got.

(Example 11)
<Preparation of base paper C>
100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of unbattered fine quality old paper pulp (freeness 500 ml), and 100 parts of hardwood bleached kraft pulp (freeness) 500 ml), 1.0 part of cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) common to the surface layer, intermediate layer and back surface layer for each pulp raw material, acidic rosin sizing agent (AL1212, Starlight PMC) 0.1 part) and 1.0 part of a liquid sulfuric acid band were blended, and talc was blended by adjusting the addition amount so that the ash content was 5% to obtain a paper stock. Each of these stocks is made with a long paper machine, the basis weight of the surface layer is 40 g / m ² , the basis weight of the intermediate layer is 100 g / m ² , and the basis weight of the back layer is 40 g / m ² , Three layers were made together to produce a base paper C having a basis weight of 180 g / m ^{2 for} the entire base paper.

  In Example 1, except that the base paper A was changed to the base paper C, a multi-layered waste paper pulp blended paper K was obtained in the same manner as in Example 1.

(Example 12)
<Preparation of base paper D>
The pulp composition of the surface layer is 80 parts of hardwood bleached kraft pulp and 20 parts of unbeaten fine wood pulp (freeness 500 ml), and the pulp composition of the middle layer is 90 parts of unbeaten fine paper pulp and 10 parts of hardwood bleached kraft pulp (freeness 500 ml). ) And 80 parts of hardwood bleached kraft pulp and 20 parts of unbeaten fine pulp (freeness 500 ml), and cationized starch (common to the surface layer, intermediate layer and back layer) for each pulp raw material. Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.), 1.0 part, acidic rosin sizing agent (AL1212, manufactured by Seiko PMC Co., Ltd.), 0.1 part, and liquid sulfuric acid band, 1.0 part, The amount of talc added was adjusted so that the ash content would be 5%, and a paper stock was prepared. Each of these stocks is made with a long paper machine, and the basis weight of the surface layer is 30 g / m ² , the basis weight of the intermediate layer is 120 g / m ^2, and the basis weight of the back layer is 30 g / m ² , Three layers were made together to produce a base paper D having a basis weight of 180 g / m ^{2 for} the entire base paper.

  In Example 1, except that the base paper A was changed to the base paper D, a multi-layered used paper pulp blended paper L was obtained in the same manner as in Example 1.

(Example 13)
In Example 3, except that the base paper A was changed to the base paper C, a multi-layered waste paper pulp blended paper M was obtained in the same manner as in Example 3.

(Example 14)
In Example 3, except that the base paper A was changed to the base paper D, a multi-layered waste paper pulp blended paper N was obtained in the same manner as in Example 3.

(Example 15)
In Example 1, instead of the 5% diluted solution A of the ultraviolet absorber, 50 parts of the 5% diluted solution A of the ultraviolet absorber and 50 parts of the 5% diluted solution A of sodium hypophosphite were mixed and stirred. In the same manner as in Example 1 except that the treatment liquid was applied to both sides of the base paper A and dried so that the weight after drying of the treatment liquid was 0.4 g / m ² per side. Paper O was obtained.

(Example 16)
<Preparation of base paper E>
100 parts of hardwood bleached kraft pulp for the surface layer, 90 parts of unbeaten fine paper pulp and 10 parts of hardwood bleached kraft pulp (freeness 500 ml) for the intermediate layer, and 80 parts of hardwood bleached kraft pulp for the back layer And 20 parts (freeness 500 ml) of unbeaten high-quality waste paper pulp, and 1.0% cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) common to the surface layer, intermediate layer and back layer for each pulp raw material. Part, 0.1 part of acidic rosin sizing agent (AL1212, produced by Seiko PMC) and 1.0 part of liquid sulfuric acid band, and further adjust the addition amount so that the ash content is 5%. And blended into a paper stock. Each of these stocks is made with a long paper machine, and the basis weight of the surface layer is 30 g / m ² , the basis weight of the intermediate layer is 120 g / m ^2, and the basis weight of the back layer is 30 g / m ² , Three layers were made together to produce a base paper E having a basis weight of 180 g / m ^{2 for} the entire base paper.

  In Example 1, except that the base paper A was changed to the base paper E, a multi-layered waste paper pulp blended paper P was obtained in the same manner as in Example 1.

(Example 17)
In Example 3, except that the base paper A was changed to the base paper E, a multi-layered waste paper pulp blended paper Q was obtained in the same manner as in Example 3.

(Example 18)
<Preparation of base paper F>
The pulp composition of the surface layer is 100 parts of broad-leaved bleached kraft pulp, the pulp composition of the intermediate layer is 100 parts of unbeaten fine quality old paper pulp and the pulp material 45 parts of the base paper A dissociated in the back layer and the hardwood bleached kraft pulp 55 parts, For each pulp raw material, 1.0 part of cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) and acidic rosin sizing agent (AL1212, manufactured by Seiko PMC Co., Ltd.) are commonly used for the surface layer, intermediate layer and back layer. 0.1 part and 1.0 part of a liquid sulfuric acid band were blended, and talc was blended by adjusting the addition amount so that the ash content was 5% to obtain a paper stock. These stock, paper making at each length paper machine, 52.5 g / ^{m 2} basis weight of the surface layer, the basis weight of the basis weight of the intermediate layer 75 g / ^{m 2} and the back surface layer 52.5 g / As m ² , three layers were combined to produce a base paper F having a basis weight of 180 g / m ^{2 for} the entire base paper.

  In Example 1, except that the base paper A was changed to the base paper F, a multi-layered waste paper pulp blending paper R was obtained in the same manner as in Example 1.

(Example 19)
In Example 3, except that the base paper A was changed to the base paper F, a multi-layered waste paper pulp blended paper S was obtained in the same manner as in Example 3.

(Example 20)
In Example 1, except that the surface on which the 5% diluted solution A of the ultraviolet absorber was applied was only the surface layer of the base paper A, the multilayer paper-making waste paper pulp blended paper A- 2 was obtained.

(Example 21)
In Example 3, the surface of the surface layer of the base paper A is changed to the surface of the base paper A except that the surface to which the 5% sodium hypophosphite diluent A is applied is the same as in Example 3. -3 was obtained.

(Example 22)
In Example 15, except that the surface on which the treatment liquid obtained by mixing and stirring the 5% diluted solution A of the ultraviolet absorber and the 5% diluted solution A of sodium hypophosphite was applied only to the surface layer of the base paper A was used. In the same manner as in Example 15, multi-layered waste paper pulp blended paper A-4 was obtained.

(Comparative Example 1)
In Example 1, a multi-layered waste paper pulp blending paper T was obtained in the same manner as in Example 1 except that the 5% diluted solution A of the ultraviolet absorber was not applied.

(Comparative Example 2)
<Preparation of base paper G>
The pulp composition is 59 parts of broad-leaved bleached kraft pulp and 41 parts of unpulverized fine waste paper pulp (freeness 500 ml), and 1.0 part of cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) with respect to this pulp raw material. , 0.1 parts of acidic rosin sizing agent (AL1212, manufactured by Seiko PMC Co., Ltd.) and 1.0 part of liquid sulfuric acid band are blended by adjusting the addition amount so that the talc content is 5%. And made paper. This stock was made with a circular paper machine to produce a base paper G having a single layer basis weight of 180 g / m ² .

  In Example 1, except that the base paper A was changed to the base paper G, a single-layered waste paper pulp blended paper U was obtained in the same manner as in Example 1.

(Comparative Example 3)
100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of unbattered fine quality old paper pulp (freeness 500 ml), and 100 parts of hardwood bleached kraft pulp (freeness) 500 ml), 1.0 part of cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) common to the surface layer, intermediate layer and back surface layer for each pulp raw material, acidic rosin sizing agent (AL1212, Starlight PMC) 0.1 part), 1.0 part of liquid sulfuric acid band, 0.4 part of UV absorber dispersion A, and further adjust the addition amount so that talc has an ash content of 5%. And blended into a paper stock. These stock, paper making at each length paper machine, 52.5 g / ^{m 2} basis weight of the surface layer, a 75 g / ^{m 2} basis weight of the intermediate layer, the basis weight of the back layer 52.5 g / As m ² , the three layers were combined to obtain a multilayer paper used recycled pulp V having a basis weight of 180 g / m ^{2 for} the entire base paper.

(Comparative Example 4)
<Preparation of base paper H>
The pulp composition is 59 parts of broad-leaved bleached kraft pulp and 41 parts of unpulverized fine waste paper pulp (freeness 500 ml), and 1.0 part of cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) with respect to this pulp raw material. , 0.1 parts of acidic rosin sizing agent (AL1212, manufactured by Seiko PMC Co., Ltd.) and 1.0 part of liquid sulfuric acid band are blended by adjusting the addition amount so that the talc content is 5%. And made paper. These stocks were made with a circular paper machine to produce a base paper H having a single layer basis weight of 180 g / m ² .

  In Example 3, except that the base paper A was changed to the base paper H, a single-layer wastepaper pulp blended paper W was obtained in the same manner as in Example 3.

(Comparative Example 5)
100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of hardwood bleached kraft pulp (freeness 500 ml), 100 parts of unbattered fine quality old paper pulp (freeness 500 ml), and 100 parts of hardwood bleached kraft pulp (freeness) 500 ml), 1.0 part of cationized starch (Neotac 40T, manufactured by Nippon Food Processing Co., Ltd.) common to the surface layer, intermediate layer and back surface layer for each pulp raw material, acidic rosin sizing agent (AL1212, Starlight PMC) 0.1 part), 1.0 part of liquid sulfuric acid band, 0.4 part of sodium hypophosphite dispersion A, and the addition amount so that talc has an ash content of 5%. It adjusted and mix | blended and it was set as paper stock. These stock and paper at each length paper machine, 52.5 g / ^{m 2} basis weight of the surface layer, the basis weight of the basis weight of the intermediate layer 75 g / ^{m 2} and the back surface layer 52.5 g / m as ^2, combined paper making three layers, the basis weight of the entire base paper was obtained in 180 g / m ² multilayer paper making waste paper pulp paper X.

  The evaluation of Examples and Comparative Examples was performed as follows. The results are shown in Tables 1 and 2.

数１において、照射前の前記表面層又は前記裏面層の測定値をＬ^＊ｘ，ａ^＊ｘ，ｂ^＊ｘとし、照射後の前記表面層又は前記裏面層の測定値をＬ^＊，ａ^＊，ｂ^＊とする。 (Light resistance test)
About the surface layer and the back layer of the obtained multilayer paper waste paper pulp-blended papers A to X, using a light resistance tester (Weatherometer Ci4000, manufactured by Atlas Co.) according to JIS B 7754: Environment 40 ° C., 50% R.D. H. ΔE ^* in condition 1 for samples after irradiation and before irradiation when a xenon arc lamp was irradiated for 10 hours under conditions of a black standard temperature of 63 ° C. and a wavelength of 340 nm and an illuminance of 0.5 w / m ^2. Calculated. The lamp filter for the light source uses a quartz glass filter (trade name: quartz filter, manufactured by Atlas) on the inside, and an infrared absorption coating filter (trade name: type S-CIRA filter, manufactured by Atlas) on the outside, and has a wavelength of 340 nm as described above. and intensity of 300~400nm region when the illuminance 0.5 w / ^{m 2} was 54w / ^{m 2.}
(Condition 1)
Using a method of calculating from the lightness index L ^* and the perceptual chromaticity index a ^* and b ^* defined in JIS P 8150: 2004 “Paper and paperboard—Method of measuring color (C / 2 °) —diffuse illumination method” ΔE ^* is determined for both the surface layer and the back layer. ΔE ^* is calculated from Equation 1.

In Equation 1, the measured value of the surface layer or the back surface layer before irradiation is L ^* x, a ^* x, b ^* x, and the measured value of the surface layer or the back surface layer after irradiation is L ^* , a ^*. , B ^* .

  Next, ink jet printing suitability evaluation was performed.

(Preparation of coating liquid A for inkjet ink receiving layer)
50 parts of amorphous synthetic silica (silo jet P407, manufactured by Grace Devison) with an average particle diameter of 7 μm by laser diffraction method and 50 parts of amorphous synthetic silica (74 × 6500, manufactured by Grace Devison) with an average particle diameter of 6 μm Water and 0.5 part of acetic acid as a pH adjuster were added, and a 25% pigment slurry was prepared with a Cowles disperser. In this pigment slurry, 17.5 parts by dry weight of polyvinyl alcohol (PVA-117, manufactured by Kuraray Co., Ltd.) and ethylene vinyl acetate binder (Sumikaflex 450, manufactured by Sumitomo Chemical Co., Ltd.) as an adhesive with respect to 100 parts of dry weight of the pigment. ) 24 parts were added and stirred, and water was further added to obtain a coating solution A having a solid content concentration of 23%.

(Reference Example 23)
Bar coating was applied to the surface of the back surface layer of the multilayer paper used pulp-mixed paper A obtained in Example 1 so that the weight after drying was 8 g / m ^2, and hot air was blown by a 120 ° C. dryer. This was dried to obtain a multilayer paper for waste ink-jet pulp blending paper a.

(Reference Example 24)
Bar coating was applied to the surface of the back layer of the multi-layered waste paper pulp blended paper C obtained in Example 3 so that the mass after drying was 8 g / m ^2, and hot air was blown by a 120 ° C. dryer. This was dried to obtain multilayer paper for ink jet and pulp blended paper b.

(Reference Example 25)
Bar coating of coating liquid A was performed on the surface of the back layer of the multilayer paper-making waste paper pulp-blended paper O obtained in Example 15 so that the mass after drying was 8 g / m ^2, and hot air was blown by a 120 ° C. dryer. This was dried to obtain multilayer paper for ink jet and pulp blended paper c.

(Comparative Example 6)
Bar coating was applied to the surface of the back layer of the multilayer paper used pulp-containing paper T obtained in Comparative Example 1 so that the mass after drying was 8 g / m ^2, and hot air was blown at 120 ° C. drier. After drying, the UV absorbent dispersion A diluted to 5% is applied to both sides so that the weight after drying is 0.4 g / m ² per side, and dried to obtain a multilayer paper waste paper blended paper d It was.

(Comparative Example 7)
Bar coating was applied to the surface of the back layer of the multilayer paper used pulp-containing paper T obtained in Comparative Example 1 so that the mass after drying was 8 g / m ^2, and hot air was blown at 120 ° C. drier. After drying, 5% dilute solution A of sodium hypophosphite was applied to both sides so that the weight after drying was 0.4 g / m ² per side, and dried to obtain multilayer paper-making waste paper pulp blended paper e. .

(Comparative Example 8)
The multilayer paper used pulp-mixed paper A obtained in Example 1 was used as the multilayer paper recycled paper pulp-mixed paper f of Comparative Example 8.

(Inkjet printing suitability)
Using a commercially available full-color inkjet printer (trade name: PM-A950, manufactured by Seiko Epson Corporation), print a photographic image on the back layer side to which the inkjet ink receiving layer has been applied, and suitability for inkjet printing such as border blur and color density Evaluated.

The evaluation of the suitability for in-jet printing was described according to the following procedure.
<Bleeding at the border>
(Double-circle): There is no bleeding in a boundary part and a boundary is very clear (a level which is satisfactory practically).
○: There is no bleeding at the boundary and the boundary is clear (a level that causes no problem in practical use).
(Triangle | delta): There exists a blur in a boundary part and a boundary is unclear (practical use unsuitable level).
X: There is a blur at the boundary, and the boundary is very unclear (practical inappropriate level).

<Color density>
(Double-circle): The density | concentration is high and it is very clear (a level which is satisfactory practically).
○: Concentration is high and clear (a level causing no problem in practical use).
(Triangle | delta): A density | concentration is low and it is unclear (practical use unsuitable level).
X: The density is low and it is very unclear (practical unsuitable level).

<Water resistance of printing>
The printed image portion was immersed in running water for 5 minutes, and the degree of bleeding of the printed image was evaluated. The evaluation criteria are as follows.
(Double-circle): There is no bleeding in a boundary part and a boundary is very clear (a level which is satisfactory practically).
○: There is no bleeding at the boundary and the boundary is clear (a level that causes no problem in practical use).
(Triangle | delta): There exists a blur in a boundary part and a boundary is unclear (practical use unsuitable level).
X: There is a blur at the boundary, and the boundary is very unclear (practical inappropriate level).

(Light resistance test)
The light resistance test was performed on the surface layer and the back layer of the obtained multilayer paper used pulp composite paper a to c for inkjet and the multilayer paper pulp composite paper df. The evaluation method was the same as the evaluation of the multi-layered paper pulp blended papers A to X.

  As is clear from Table 1, the multilayer paper waste paper blended paper obtained in the examples according to the present invention is a base paper having a multilayer paper of three or more layers, and the waste paper pulp blending ratio of the intermediate layer is increased. By applying at least one of an ultraviolet absorber or sodium hypophosphite to the surface of the paper, it has good light resistance even if the proportion of the waste paper-mixed pulp in the entire base paper is 40% or more. confirmed. In particular, as shown in Examples 4 to 6, Example 8 or Example 10, it was confirmed that better light resistance was obtained by blending the fluorescence quencher into the used paper pulp blending layer. On the other hand, Comparative Example 1 in which neither an ultraviolet absorber nor sodium hypophosphite was applied, Comparative Example 2 and Comparative Example 4 in which the base paper was made into a single layer paper, and an ultraviolet absorber or sodium hypophosphite were used as a paper material. In Comparative Example 3 and Comparative Example 5 incorporated therein, the discoloration after the light resistance test was large.

  Furthermore, as can be seen from Table 2, the multi-layer wastepaper pulp blended paper for inkjet using the multi-layer wastepaper pulp blended paper obtained in the examples according to the present invention has both good ink jet printability and light resistance. I confirmed that I can do it. In Comparative Examples 6 and 7, after the inkjet ink receiving layer was provided, an ultraviolet absorber or sodium hypophosphite was applied, so that light resistance was obtained, but absorption of the inkjet ink was hindered, and inkjet printing was performed. Poor aptitude. In Comparative Example 8, since no ink jet ink receiving layer was provided, ink jet printing suitability could not be obtained.

Claims (5)

The base paper is a multi-layered paper having three or more layers, and the ratio of the used paper pulp to the whole of the base paper is 40% by mass or more.
Of the layers of the base paper, a layer disposed on one surface is represented as a surface layer, a layer disposed on the other surface is represented as a back layer, and a layer disposed between the surface layer and the back layer is represented as an intermediate layer. When
(1) The intermediate layer is one or more layers,
(2) The mixing ratio of the waste paper pulp of the intermediate layer is 90% by mass or more,
(3) The blending ratio of the waste paper pulp of either the front layer or the back layer or both layers is 20% by mass or less,
(4) At least one surface of the surface layer or the back surface layer is a coated surface coated with a treatment liquid containing either or both of an ultraviolet absorber and sodium hypophosphite,
(5) A multi-layered waste paper pulp blending paper characterized by having no ink-jet ink receiving layer. When the xenon arc lamp is irradiated with a light resistance tester according to JIS B 7754: 1991 “Xenon arc lamp light resistance and weather resistance test machine”, ΔE ^* obtained in condition 1 satisfies condition 2 The multilayer papermaking pulp blending paper according to claim 1 characterized by the above-mentioned.
(Condition 1)
Using a method of calculating from the lightness index L ^* and the perceptual chromaticity index a ^* and b ^* defined in JIS P 8150: 2004 “Paper and paperboard—Method of measuring color (C / 2 °) —diffuse illumination method” ΔE ^* is determined for both the surface layer and the back layer. ΔE ^* is calculated from Equation 1.

In Equation 1, the measured value of the surface layer or the back surface layer before irradiation is L ^* x, a ^* x, b ^* x, and the measured value of the surface layer or the back surface layer after irradiation is L ^* , a ^*. , B ^* .
(Condition 2)
When one surface of the surface layer or the back surface layer is a coated surface, ΔE ^{* of the} coated surface is 2.5 or less, and when both surfaces of the surface layer and the back surface layer are coated surfaces, ΔE ^{* on} both sides is 2.5 or less.   The multilayer paper waste paper blended paper according to claim 1 or 2, wherein the layer containing the waste paper pulp contains a fluorescence deactivator. In the method for producing a multi-layer waste paper pulp blended paper, wherein the base paper is a multi-layer paper having three or more layers, and the ratio of the waste paper pulp in the whole base paper is 40% by mass or more,
Of the layers of the base paper, a layer disposed on one surface is represented as a surface layer, a layer disposed on the other surface is represented as a back layer, and a layer disposed between the surface layer and the back layer is represented as an intermediate layer. When
The intermediate layer is formed of one or more layers, the blending ratio of the used paper pulp of the intermediate layer is 90% by mass or more, and either the surface layer or the back layer or both layers of the used paper pulp A base paper preparation step of making the base paper with a blending ratio of 20% by mass or less;
An application step of applying a treatment liquid containing either one or both of an ultraviolet absorber and sodium hypophosphite to at least one surface of the surface layer or the back layer;
The method for producing a multi-layer waste paper pulp blending paper, wherein the multi-layer waste paper pulp blend paper does not have an inkjet ink receiving layer.   5. The method for producing a multi-layered waste paper pulp blending paper according to claim 4, wherein the base paper preparation step is a step of blending a layer containing waste paper pulp with a fluorescent deactivator to make paper.