Paperboard, base paper for impregnation processing, and resin-impregnated paper

Abstract

To provide a bulky paperboard, base paper for impregnation processing having the paperboard, and resin-impregnated paper.SOLUTION: Disclosed are: a paperboard which is characterized by including a single paper layer or a plurality of paper layers, in which at least one layer among the paper layers is a bulky layer including a waste paper pulp and a bulking agent and the bulky layer includes 0.1 wt.% or over and 10 wt.% or under of the bulking agent to a fiber for paper making; base paper for impregnation processing having the paperboard; and resin-impregnated paper having the base paper for impregnation processing.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to paperboard and resin impregnated paper. [Background technology]

[0002] Paperboard is generally required to be strong. Bulking agents are not usually added to paperboard because they reduce the strength. Paperboard is used for cardboard liners, paper containers, etc., but high-strength paperboard has a high density and specific gravity, so it is required to be lightweight. Patent Document 1 proposes a bulky paperboard consisting of three or more layers, with the pulp fraction in the middle layer having a length-weighted average fiber length of 1.0 mm or less being 9.0% or less. Patent Document 1 aims to prevent the gaps between fibers from being filled by reducing the amount of fine fibers in the middle layer, and for recycled paper pulp that contains a large amount of fine fibers, the fine fibers are removed before use. Patent Document 2 proposes a bulky paperboard containing Arundodonax pulp. Arundodonax is a type of reed, and Patent Document 2 uses an uncommon non-wood pulp. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-098496 A [Patent Document 2] JP 2004-068219 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a bulky paperboard, and an impregnation processing base paper and a resin-impregnated paper each having the bulky paperboard. [Means for solving the problem]

[0005] The means for solving the problems of the present invention are as follows. 1. It has one or more paper layers; At least one of the paper layers is a bulky layer containing recycled paper pulp and a bulking agent, The paperboard, wherein the bulky layer contains 0.1% by weight or more and 10% by weight or less of a bulking agent relative to the papermaking fibers. 2. The density of the bulky layer is 0.4 g / cm 3 More than 0.6g / cm 3 1. The paperboard according to claim 1, characterized in that: 3. The paperboard according to 1 or 2, wherein the bulky layer is located on the outermost surface. 4. The Klemm water absorption height measured in accordance with JIS P8141 is 20 mm or more. 4. The paperboard according to any one of 1. to 3., characterized in that the castor oil penetration is 250 seconds or less. 5.4. A paperboard for impregnation. Resin-impregnated paper having the impregnation processing base paper described in 6.5. Effect of the Invention

[0006] According to the present invention, a novel paperboard can be provided. The paperboard of the present invention is bulky and lightweight. Since the voids between the fibers are maintained, the paperboard of the present invention has excellent water and oil absorbency. The paperboard of the present invention can be suitably used as impregnating base paper, cleaning sheets, water-absorbing sheets, oil-absorbing sheets, etc., and in particular can be impregnated with resin to form resin-impregnated paper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The paperboard of the present invention comprises a single or multiple paper layers, At least one of the paper layers is a bulky layer containing recycled paper pulp and a bulking agent, The bulky layer contains a bulking agent in an amount of 0.1% by weight to 10% by weight based on the weight of the papermaking fiber.

[0008] The paperboard of the present invention comprises a single layer or multiple layers. The number of layers can be adjusted according to the basis weight of the paperboard, and can be, for example, 6 layers or less. The basis weight of the paperboard of the present invention is not particularly limited, but may be, for example, 130 g / m 2 More than 150g / m 2 More than 170g / m 2 More than 190g / m 2 The upper limit of the basis weight is not particularly limited as long as it can be produced by a papermaking machine, but it is preferably, for example, 600 g / m 2 Below 550g / m 2 Below 500g / m 2 It can be as follows etc. The thickness of the paperboard of the present invention is not particularly limited, but can be, for example, 200 μm or more, 240 μm or more, 280 μm or more, 320 μm or more, etc. The upper limit of the thickness is not particularly limited as long as it can be produced by a papermaking machine, but can be, for example, 1000 μm or less, 900 μm or less, 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, 400 μm or less, etc.

[0009] In the paperboard of the present invention, at least one of the paper layers is a bulky layer containing recycled paper pulp and a bulking agent. When the paper layer is a multi-layered paper board, it may have two or more bulky layers, and all layers may be bulky layers, and the pulp materials of the multiple bulky layers may be the same or different. When the paperboard is a single layered paperboard, the single layer is a bulky layer. Examples of waste paper pulp that can be used include waste paper pulp obtained by disintegrating unprinted waste paper such as cardboard, white, extra white, medium white, and white damage; waste paper printed on fine paper, fine coated paper, medium quality paper, medium quality coated paper, and recycled paper; and written waste paper, papers such as discarded confidential documents, waste magazines, and waste newspapers that have been disintegrated and then deinked (DIP).

[0010] The bulky layer may contain recycled paper pulp, and may also contain other pulps. As raw material pulps other than recycled paper pulp, various pulps derived from wood fibers, such as bleached softwood kraft pulp (NBKP), bleached hardwood kraft pulp (LBKP), unbleached softwood kraft pulp (NUKP), unbleached hardwood kraft pulp (LUKP), groundwood pulp (GP), refiner ground pulp (RGP), chemical pulp (CP), thermomechanical pulp (TMP), and chemi-thermomechanical pulp (CTMP), and non-wood pulps obtained from kenaf, bagasse, bamboo, hemp, straw, etc., can be used without particular limitation. However, since recycled paper pulp is cheaper than other pulps, the bulky layer preferably contains recycled paper pulp at a ratio of 50% by weight or more to the total papermaking fibers, more preferably 70% by weight or more, even more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 98% by weight or more, and even more preferably 99% by weight or more.

[0011] When the paperboard of the present invention has multiple paper layers, the type of papermaking fiber contained in the paper layers other than the bulky layer is not particularly limited, and the above-mentioned various pulps can be used without any particular restrictions. However, since recycled paper pulp is cheaper than other pulps, the paper layers other than the bulky layer preferably contain recycled paper pulp at 50% by weight or more of the total papermaking fiber, more preferably 70% by weight or more, even more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 98% by weight or more, and even more preferably 99% by weight or more.

[0012] The bulky layer contains a bulking agent in an amount of 0.1% by weight to 10% by weight based on the total papermaking fibers contained in the bulky layer. The bulking agent is an agent that reduces the density of paper by inhibiting the formation of bonds between papermaking fibers. As the bulking agent, any agent used in the papermaking field can be used without any particular limitation. As the bulking agent, a commercially available product can be used, for example, acrylic polymer additive PHL (Nippon Paper Industries Co., Ltd.), N327 (manufactured by Chukyo Yushi Co., Ltd., stearic acid monoamide), etc. can be used. Note that a paper layer that is not a bulky layer can also contain a bulking agent.

[0013] The amount of the bulking agent relative to the total papermaking fibers contained in the bulky layer is not particularly limited, but the strength of the paper decreases as the amount of the bulking agent increases. If the wet tensile strength of the resulting paper is less than 1.0 kN / m, the paper is likely to break during the manufacturing process, so it is preferable to adjust the amount of the bulking agent so that the wet tensile strength of the resulting paper is 1.0 kN / m or more. The amount of the bulking agent is preferably 8% by weight or less, more preferably 6% by weight or less. The wet tensile strength of the resulting paperboard is more preferably 1.5 kN / m or more, and even more preferably 2.0 kN / m or more. In this specification, the wet tensile strength means a value measured in accordance with the general method of JIS P8135:1998.

[0014] The paperboard of the present invention may contain additives used in the papermaking field, such as wet strength agents, dry strength agents, pigments, drainage improvers, internal sizing agents, pH adjusters, defoamers, pitch control agents, slime control agents, calcium carbonate, kaolin, talc and other fillers, etc. The amount of each additive used is not particularly limited.

[0015] In the paperboard of the present invention, the density of the bulky layer is 0.4 g / cm 3 More than 0.6g / cm 3 The density of the bulky layer is preferably 0.58 g / cm or less. 3 Less than 0.56 g / cm is preferred. 3 Less than 0.54 g / cm is more preferable. 3 More preferably, 0.52 g / cm3 More preferably, 0.50 g / cm 3 Even more preferred is the following: The paperboard of the present invention has a density of 0.4 g / cm3 as a whole. 3 More than 0.62g / cm 3 The density of the entire paperboard is preferably 0.6 g / cm or less. 3 Less than 0.58 g / cm is preferred. 3 Less than 0.56 g / cm is more preferable. 3 More preferably, 0.54 g / cm 3 More preferably, the following is 0.52 g / cm 3 More preferably, 0.50 g / cm 3 Even more preferred is the following:

[0016] In the paperboard of the present invention, the bulky layer has a low density. The arrangement of the bulky layer is not particularly limited, and if the bulky layer is located on the outermost surface of the paperboard, a paperboard having excellent water absorption, oil absorption, impregnation, etc. can be obtained. If the bulky layer is located inside the paperboard other than the outermost surface, a paperboard having excellent cushioning, sound absorption, etc. can be obtained.

[0017] When the paperboard of the present invention is used for applications requiring absorbency, it is preferable that the Klemm water absorption height measured according to JIS P8141 is 20 mm or more. If the Klemm water absorption height is less than 20 mm, the absorbency is insufficient and the paperboard is not suitable for applications requiring absorbency. When the paperboard of the present invention is used for cleaning sheets, absorbent sheets, etc., the Klemm water absorption height is more preferably 25 mm or more, and even more preferably 30 mm or more. The upper limit of the Klemm water absorption height is not particularly limited, but is, for example, 100 mm or less, 90 mm or less, 80 mm or less, 70 mm or less, etc.

[0018] When the paperboard of the present invention is used for applications requiring oil absorption, the castor oil penetration is preferably 250 seconds or less. If the castor oil penetration exceeds 250 seconds, the oil absorption is insufficient and the paperboard is not suitable for applications requiring oil absorption. When the paperboard of the present invention is used for cleaning sheets, oil absorbing sheets, etc., the castor oil penetration is more preferably 230 seconds or less, even more preferably 210 seconds or less, and even more preferably 190 seconds or less. The lower limit of the castor oil penetration is not particularly limited, but is, for example, 50 seconds or more, 60 seconds or more, 70 seconds or more, 80 seconds or more, etc. The castor oil penetration is known as a method for evaluating the permeability of base paper, and can be measured by the method described in the following examples.

[0019] The paperboard of the present invention can be suitably used as a paperboard for cardboard liners, corrugating medium base paper, paperboard for paper containers, paperboard for box making, paperboard for laminated paper, etc. Furthermore, by taking advantage of its low density bulky layer characteristics, the paperboard of the present invention can be suitably used as a base paper for impregnation, cleaning sheet, water absorbing sheet, oil absorbing sheet, etc. In particular, a paperboard having a Klemm water absorption height of 20 mm or more and a castor oil penetration rate of 250 seconds or less has excellent resin solution impregnation properties and can therefore be suitably used as a base paper for impregnation, and resin-impregnated paper can be obtained by impregnating and curing melamine resin, phenol resin, urea resin, etc. EXAMPLES

[0020] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to such examples. In addition, unless otherwise specified in this specification, concentrations, parts, etc. are based on weight, and numerical ranges are described as including their endpoints.

[0021] Evaluation method <Basic weight> Measurements were performed based on JIS P8124:1998. <Thickness> Measurements were taken based on JIS P8118:2014. <density> It was calculated from the basis weight and thickness.

[0022] <Klemm water absorption height> Measurements were performed based on JIS P8141:2004. <Castor oil penetration> Ten test pieces measuring 20 mm square are cut from the base paper. A container containing castor oil is placed in a thermostatic bath with water at a temperature of 30°C, and the temperature of the castor oil is controlled to a constant 30°C. The test piece was dropped horizontally onto the surface of the castor oil, and the time from the moment the test piece came into contact with the oil until the oil had uniformly permeated the upper surface of the test piece was measured. Five test pieces were measured on both sides of the laminate base paper, and the average value was calculated.

[0023] <Wet strength> A sheet cut to a width of 15 mm and a length of 100 mm in the longitudinal direction was immersed in ion-exchanged water or distilled water at 20°C for 10 minutes, after which excess water on the surface was removed and measurements were made based on the general method of JIS P 8135:1998 "Paper and paperboard - Wet tensile strength test method".

[0024] Experiment 1: Examples 1 to 9, Comparative Example 1 The amount of acrylic polymer additive (Nippon Paper Industries, PHL) was added as a bulking agent to the recycled cardboard pulp in the amounts shown in Table 1, and the target basis weight was 200 g / m in accordance with JIS P8222. 2 The sheet was prepared, sandwiched between thin filter paper and pressed for 2 minutes. It was then dried for 1 minute in a cylinder dryer at 140°C, and then dried for 30 minutes in a blower dryer at 50°C to prepare a paperboard. The blending amounts and evaluation results are shown in Table 1. In Tables 1 to 3, the blending amount of the bulking agent is in parts by weight relative to the papermaking fibers.

[0025] [Table 1]

[0026] result By adding a bulking agent, which is a cement dispersant, it was possible to obtain a low-density paperboard. As the amount of bulking agent added increased, the paperboard became bulkier and its water and oil absorption properties improved.

[0027] Experiment 2: Examples 10 to 14 Paperboard was produced in the same manner as in Experiment 1 above, except that a paper bulking agent (N327, stearic acid monoamide, manufactured by Chukyo Yushi Co., Ltd.) was added to the recycled cardboard pulp in the amounts shown in Table 2. The formulation and evaluation results are shown in Table 2 together with Comparative Example 1.

[0028] [Table 2]

[0029] result By adding a paper bulking agent, it was possible to obtain a paperboard with a low density. As the amount of the bulking agent added increased, the paperboard became bulkier and its water and oil absorption properties improved.

[0030] Experiment 3: Examples 15 to 18, Comparative Examples 2 and 3 Paperboards were prepared in the same manner as in Experiment 1 above, except that a bulking agent was added to the recycled newspaper pulp or imitation recycled tea paper pulp in the amounts shown in Table 3. The formulation and evaluation results are shown in Table 3.

[0031] [Table 3]

[0032] result When newspaper pulp or imitation tea paper pulp was used as recycled paper pulp, the addition of a bulk-increasing agent increased the bulk of the paperboard (low density) and improved its water and oil absorbency.

Claims

1. It comprises one or more paper layers, At least one of the paper layers is a bulky layer containing recycled paper pulp and a bulking agent, The paperboard, wherein the bulky layer contains a bulking agent in an amount of 0.1% by weight to 10% by weight based on the weight of the papermaking fibers.

2. The density of the bulky layer is 0.4 g / cm ３ 0.6g / cm or more ３ 2. The paperboard of claim 1, wherein:

3. 3. The paperboard of claim 1 or 2, wherein the lofty layer is located on the outermost surface.

4. The Klemm water absorption height measured in accordance with JIS P8141 is 20 mm or more, 3. The paperboard of claim 1 or 2, characterized in that the castor oil penetration is 250 seconds or less.

5. A base paper for impregnation comprising the paperboard according to claim 4.

6. A resin-impregnated paper comprising the impregnation processing base paper according to claim 5.

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