JP4533945B2 - Impregnated base paper for flooring and impregnated paper for flooring - Google Patents

Description

  The present invention relates to an impregnated base paper for flooring used as a reinforcing material for plywood constituting the flooring and an impregnated paper for flooring.

  Conventionally, for example, as shown in Patent Document 1, a decorative board for flooring or the like is generally configured to include a decorative sheet, an adhesive layer, and a plywood. In particular, veneer plywood is often used as the plywood in composite flooring flooring, but MDF (medium density laminated board) is used as the reinforcing material. However, when MDF is used as a reinforcing material, the cost is not only higher than a floor material composed of a single plywood, but it absorbs moisture and swells, and the floor surface is likely to be wavy. There is a problem of getting worse. Thus, it has been proposed to provide a resin impregnated paper cured layer (kraft paper) as a reinforcing material in addition to MDF, as shown in Patent Document 1, for example. This resin-impregnated paper cured layer impregnates the base paper with a cured resin such as a phenolic resin, thereby maintaining the impact resistance of the flooring and covering the irregularities formed on the surface of the flooring. Is not formed.

  Moreover, with the recent increase in demand for wood, the price of veneer has soared, making it difficult to obtain veneer plywood. Therefore, in order to reduce the manufacturing cost, relatively inexpensive Chinese-made veneer plywood has been used. However, Chinese-made veneer plywood is soft, has low impact resistance, and has poor surface properties. For this reason, conventional kraft paper with a thickness of about 0.3 mm cannot secure impact resistance as a flooring material, and also cannot cover unevenness formed on the surface of the flooring material. A base paper suitable for paper has been demanded.

  In addition, when V-cut processing is applied to a flooring material using kraft paper with a thickness of about 0.3 mm as a reinforcing material, the veneer plywood itself can be seen, resulting in a poor appearance of the flooring material. It was. Thus, a method of laminating two kraft papers having a thickness of about 0.3 mm is used, but there is a problem that the peel strength is lowered on the kraft paper laminating surface and the number of processing steps is increased.

  Furthermore, conventional kraft paper has a problem that it is difficult to obtain the impact resistance necessary for use as a flooring material because of its poor impregnation with resin or the like. Therefore, there are means such as increasing the freeness of the raw material pulp to improve the impregnation property, lowering the press linear pressure in the paper making process, the calendar linear pressure, etc., but any means weakens the entanglement between the pulp fibers, As a result, the inter-fiber strength is lowered, the interlaminar strength as impregnated base paper for flooring or impregnated paper for flooring cannot be ensured, and it is difficult to ensure impact resistance. Arise.

  In addition, as a reinforcing material for flooring, it has been proposed to use a prepreg shown in Patent Document 2 or a fibrous sheet coated with a synthetic resin solution shown in Patent Document 3, but these Even the technology could not solve the above problems.

JP 2007-77726 A JP 2003-314043 A JP 2002-172604 A

  The present invention has been made in view of the above-described circumstances, and the object of the present invention is that the interlaminar strength is high even when a soft veneer plywood is used as the plywood, which has poor surface properties. Another object of the present invention is to provide an impregnated base paper for flooring and an impregnated paper for flooring that are impact resistant and can cover the unevenness formed on the surface of the flooring.

The above object of the present invention is to provide a multi-layered floor material impregnated base paper having at least two layers, a surface layer and a back layer. 20 wt% blended, NBKP blended 80-90 wt%, and the raw material pulp described in JIS-P8121 (1995) “Paper and board-pulp freeness test method—Canadian standard freeness The freeness measured according to “Test method” is adjusted to 550 to 750 cc, the paper thickness is 400 to 500 μm, and “Paper and paperboard—Test method of thickness and density” described in JIS-P8118 (1998). The density measured according to the standard is 0.3 to 0.6 g / cm ³ , and the water absorption by Klem is measured according to “Paper and paperboard—Water absorption test method—Klem method” described in JIS-P8141 (2004). Every time Is 80 to 97 mm, and J. TAPPI No. 41 (2000), the oil absorbency measured in accordance with “Paper and paperboard—oil repellency test method—kit method” is 1.3 to 1.8 seconds, and at least —CH ₂ OH group (methylol) This can be achieved by providing an impregnated base paper for flooring characterized by impregnating and applying an aqueous thermosetting resin having a base.

The above-mentioned object of the present invention can be effectively achieved by providing an impregnating base paper for flooring, wherein an impregnating liquid penetration accelerator is added to the impregnating base paper for flooring.

Further, the above object of the present invention is to form a floor material impregnated paper by impregnating and applying a water-based thermosetting resin to the floor material impregnated base paper , as described in JIS-Z0237 (2000). It is achieved by providing an impregnated paper for flooring characterized in that the interlayer strength measured in accordance with “Sheet Test Method—Tensile Strength” is longitudinal: 350 N / 15 mm or more and lateral: 200 N / 15 mm or more. The

  Furthermore, the above object of the present invention can be achieved more effectively by providing an impregnated paper for flooring characterized in that the paper thickness is 550 to 750 μm.

  According to the impregnated base paper for flooring according to the present invention, it is a multi-layer paper having at least two layers of a surface layer and a back layer, the water absorption of Klem is 80 to 113 mm, and the oil absorption is 0.5 to 2.2 seconds. Therefore, the impregnation property of the water-based thermosetting resin can be within a desired range, and the work efficiency, production cost, and operability can be excellently balanced.

  In addition, according to the floor material impregnated paper according to the present invention, the interlayer strength is set to 350 N / 15 mm or more in the vertical direction and 200 N / 15 mm or more in the horizontal direction. Even if is used, it has impact resistance and can cover the unevenness of the surface of the flooring. In particular, when a water-based thermosetting resin having a specific methylol group is used, the effect becomes remarkable.

  Hereinafter, in the case of the base paper impregnated paper for flooring and the floor material impregnated paper according to the present invention, the base paper for flooring is composed of three paper layers of a surface layer, one intermediate layer, and a back layer. An example will be described in detail. In addition, the base paper impregnated base material for flooring and the base material for floor material impregnation according to the present invention are not limited to the following embodiments, and the configuration is appropriately set within the scope of the claims. Needless to say, it can be changed.

  The impregnated base paper for flooring according to the present invention (hereinafter referred to as “the main impregnated base paper”) has three paper layers: a surface layer, one intermediate layer, and a back layer.

  The impregnated base paper is referred to as a vertical clem water absorption (hereinafter simply referred to as “Clem water absorption”) measured according to “paper and paperboard—water absorption test method—Klem method” described in JIS-P8141 (2004). ) Is preferably 80 to 113 mm, more preferably 80 to 97 mm. In addition, J.H. TAPPI No. 41 (2000), the oil absorption measured in accordance with “Paper and paperboard—oil repellency test method—kit method” (hereinafter simply referred to as “oil absorption”) is 0.5 to 2.2. It is preferable that it is second, More preferably, it is 1.3 to 1.8 second.

  If the Krem water absorption of the impregnated base paper is less than 80 mm, the impregnation property of a water-based thermosetting resin, which will be described later, becomes low, and the amount of water-based thermosetting resin impregnated decreases. For this reason, the impregnated paper formed by impregnating and applying the water-based thermosetting resin to the impregnated base paper cannot obtain a desired interlayer strength and is difficult to use as a flooring. On the other hand, if the water absorption of Klem exceeds 113 mm, the impregnation of the water-based thermosetting resin of the impregnated base paper becomes too high, and more than the required amount of water-based thermosetting resin is impregnated in the impregnated base paper. As a result, the work efficiency becomes worse and the manufacturing cost increases.

  Further, if the impregnated base paper has an oil absorption of less than 0.5 seconds, the impregnation property of the water-based thermosetting resin becomes too high, and the impregnated base paper is impregnated with more water-based thermosetting resin than necessary. It takes a long time, resulting in poor working efficiency and increased manufacturing costs. On the other hand, if the oil absorption of the impregnated base paper exceeds 2.2 seconds, the impregnation property of the water-based thermosetting resin is lowered, and the time until the required amount of the water-based thermosetting resin is impregnated becomes longer, and the operability is improved. It will decline.

  Moreover, it is preferable to mix | blend 0-30 mass% mechanical pulps, such as thermomechanical pulp (TMP) which mechanically pulped the chip | tip with heating and pressurization, in the raw material pulp of each layer which forms this impregnating raw paper More preferably, it is 10-20 mass%. When the blending ratio of the mechanical pulp in each layer exceeds 30% by mass, there arises a problem that the impregnation property of the water-based thermosetting resin of the impregnated base paper is deteriorated.

  If the raw material pulp of each layer forming the impregnated base paper contains 0 to 30% by mass of mechanical pulp, other raw material pulps include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), and hardwood. Untreated bleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP), hardwood sulfite pulp, softwood sulfite pulp and other wood fibers as main raw materials, chemically treated pulp, chemically treated pulp and chips Ground pulp that has been mechanically pulped, chemi-ground pulp that has been mechanically pulped while adding chemicals to wood or chips, and semi-chemical pulp that has been digested to a softer chip and then pulped with a refiner, etc. Virgin pulp or the like can be used. In addition, non-wood fibers such as kenaf, hemp, and straw, which are fiber materials other than wood, can also be used. In addition, pulp made from waste paper may be blended, but since there are many fine fibers, drainage becomes worse, production speed decreases, and impregnated base paper impregnated with water-based thermosetting resin is impregnated. The appearance of the paper surface deteriorates and the interlayer strength also decreases. Therefore, it is preferable not to mix the waste paper pulp with the raw material pulp that forms the surface layer and the back layer, and it is more preferable not to mix it with the raw material pulp that forms the intermediate layer.

  In addition, the impregnated base paper is preferably made of each layer using raw pulp having the same composition. For example, raw paper having a composition different from that of the surface layer, intermediate layer, and back layer, such as mixing waste paper in the raw material pulp of the intermediate layer. You may make paper using pulp.

  In addition, the raw material pulp of each layer was measured according to JIS-P8121 (1995) "Paper and paperboard-Pulp freeness test method-Canadian standard freeness test method". "Freeness") is preferably adjusted to 550 to 750 cc, more preferably 600 to 750 cc. If the freeness of the raw pulp in each layer exceeds 750 cc, the amount of water-based thermosetting resin impregnated in the impregnated base paper will increase, increasing the amount of water-based thermosetting resin used, increasing costs, and water-based thermosetting. Since the amount of the impregnated resin increases, drying takes time and the operability also decreases. In addition, since the fiber-to-fiber bonding force is reduced and the interlayer strength is lowered, when such an impregnated base paper is used as a flooring, problems such as delamination and a reduction in impact resistance occur. On the other hand, if the freeness of the raw material pulp of each layer is less than 550 cc, the fiber-to-fiber bond strength increases and the interlayer strength increases, but the impregnation property of the water-based thermosetting resin of the impregnated base paper is significantly reduced. It is difficult to obtain the desired interlayer strength, and the impact resistance is lowered.

  In addition, it is preferable to add a wet paper strength enhancer and / or a dry paper strength enhancer to at least one layer of raw pulp constituting the impregnated base paper. As a result, the processability of the impregnated base paper during the impregnation coating of the water-based thermosetting resin can be improved, and the floor material impregnation formed by impregnating the water-based thermosetting resin with the water-based thermosetting resin. The interlayer strength of the paper can be further increased. In the case where the wet paper strength enhancer is not blended, the suitability for processing may be lowered, for example, paper breakage may occur when the water-based thermosetting resin is impregnated and applied to the impregnated base paper. Further, when a dry paper strength enhancer is not blended, the interlayer strength of the floor material impregnated paper formed by impregnating and applying the water-based thermosetting resin to the impregnated base paper is lowered. It becomes difficult to use for flooring. Therefore, it is preferable to add a wet paper strength enhancer and a dry paper strength enhancer to the raw pulp of all layers constituting the impregnation raw material.

  As such a wet paper strength enhancer, for example, polyamide polyamine / epichlorohydrin type, melamine / formalin type, urea / formalin type resin and the like can be used. As the dry paper strength enhancer, anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, or the like can be used. However, the wet paper strength enhancer and the dry paper strength enhancer used for the impregnated paper are not limited to these.

  In addition, the addition of the paper strength enhancer decreases the impregnation of the water-based thermosetting resin of the impregnated base paper, so that the penetration of the impregnating liquid into the raw pulp that forms the layer to which the strength enhancer is added is promoted. It is preferable to add an agent. As the impregnating liquid permeation accelerator, an anionic surfactant, a cationic surfactant, or a nonionic surfactant can be used, or one or more of these may be used in combination.

  Anionic surfactants include alkylbenzene sulfonic acid metal salts, alkyl sulfate esters, polyoxyalkylene aryl sulfate esters, alkyl naphthalene sulfonates, naphthalene sulfonate formalin condensates, mono-substituted or di-substituted sulfosuccinates. Examples include salts.

  Cationic surfactants include quaternary ammonium salt types (stearyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride, distearyl dimethyl ammonium chloride, ethyl lanolin sulfate fatty acid aminopropylethyl dimethyl ammonium, etc.), amine salt types (diethylamino stearate). Ethyl amide lactate, dilaurylamine hydrochloride, oleylamine lactate, etc.).

  Nonionic surfactants include polyoxyalkylene sorbitol fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkyl ether, polyoxyalkylene fatty acid ester, polyoxyethylene polyoxypropylene block copolymer, ethylenediamine polyoxy Examples include ethylene polyoxypropylene block copolymers, polyoxyalkylene alkylamines, polyoxyalkylene fatty acid amides, and the like.

  Among these impregnating liquid permeation accelerators, nonionic surfactants are preferred, and it is particularly preferred to contain a polyhydric alcohol not containing polyethylene glycol and a propylene oxide adduct of a polyhydric phenol compound. Further, it is more preferable to use a liquid self-emulsifying surfactant of DF6300 (manufactured by Seiko PMC Co., Ltd.) which is a fatty acid type and does not contain silicone.

  Moreover, 0.01-0.5 mass% is preferable, and, as for the addition amount of this impregnation liquid penetration accelerator, 0.05-0.25 mass% is more preferable.

  If the addition amount of the impregnating liquid penetration accelerator is less than 0.01% by mass, the size cannot be sufficiently erased, so that the resin permeability is poor and the productivity of the impregnated paper is lowered. On the other hand, if the added amount exceeds 0.5% by mass, the sizing property can be sufficiently erased, but it tends to inhibit fixing of chemicals such as paper strength enhancers and dyes and also inhibit hydrogen bonding between pulp fibers. There arises a problem that the interlayer strength of the impregnated base paper is lowered. In addition, the peel strength of the impregnated paper after impregnation with the resin may be reduced.

  In addition, in order to give the impregnating base paper the impregnation property of the water-based thermosetting resin, it is also possible to add chemicals such as a liquid absorbing agent and a bulking agent in addition to the impregnating liquid penetration accelerator agent. However, it is not necessary to add chemicals such as an impregnating liquid penetration accelerator depending on the degree of beating of the raw pulp and the blending ratio of the pulp.

  Further, in order to increase the bulk of the impregnated base paper, that is, in order to increase the paper thickness of the impregnated base paper, the thermally foamable particles can be mixed into the raw pulp. The thermally foamable particles that can be used in the impregnated base paper are those in which a low-boiling solvent is enclosed in a fine particle outer shell composed of a thermoplastic synthetic resin mainly composed of an acrylic copolymer. The thermally foamable particles preferably have an average particle diameter of 5 to 15 μm and start to expand upon heating at 75 to 130 ° C. Examples of the thermoplastic synthetic resin constituting the outer shell include copolymers such as vinylidene chloride, acrylonitrile, acrylic acid ester, and methacrylic acid ester. Examples of the low boiling point solvent enclosed in the outer shell include isobutane, pentane, petroleum ether, hexane, low boiling point halogenated hydrocarbon, and methylsilane.

  Examples of such thermally expandable particles include “Matsumoto Microsphere F-20 Series”, “F-30 Series”, “F-36 Series”, and “F-46” manufactured by Matsumoto Yushi Seiyaku Co., Ltd. "Expancel WU" and "Same DU" sold by Nippon Philite Co., Ltd. can be used, but the thermally foamable resin used for the impregnated base paper is not limited to these.

  In addition, since the thermally foamable particles do not self-fix, it is preferable to use a mixture of a fixing agent in advance. As this fixing agent, polyacrylamide type paper strength agent, polyamide epichlorohydrin type paper strength agent, polyethyleneimine type paper strength agent, starches such as starch, oxidized starch, carboxymethylated starch, plant gum, polyvinyl alcohol, Various known materials such as carboxymethyl cellulose can be used.

  In addition, the addition amount, type, and the like of the chemical added to the raw material pulp of each layer constituting the impregnated base paper can be appropriately adjusted according to the type of raw material.

  The raw pulp described above is subjected to a known papermaking process, for example, a wire part, a press part, a dryer part, a size press, a calender part, etc., and then the impregnated base paper having three paper layers of a surface layer, an intermediate layer, and a back layer. Form. The paper making method of the impregnated base paper is not particularly limited, and any of an acidic paper making method, a neutral paper making method, and an alkaline paper making method may be used. Also, since the paper machine is not particularly limited, for example, various known paper machines such as a long net paper machine, a twin wire paper machine, a circular net paper machine, and a short net combination machine can be used. it can.

The thus-impregnated base paper formed in this manner has a density (hereinafter simply referred to as “density”) measured in accordance with “Paper and paperboard—Test method for thickness and density” described in JIS-P8118 (1998). It is adjusted to 0.3 to 0.6 g / cm ³ , preferably 0.35 to 0.55 g / cm ³ , more preferably 0.35 to 0.5 g / cm ³ . By adjusting the density of the impregnated base paper as described above, the impregnation property (impregnation amount) of the water-based thermosetting resin of the impregnated base paper can be adjusted. When the density of the impregnated base paper is less than 0.3 g / cm ³ , the impregnating property of the water-based thermosetting resin of the impregnating base paper is improved, but the impregnated base paper is impregnated with more than the required amount of the water-based thermosetting resin. Therefore, drying takes time, work efficiency is deteriorated, and manufacturing cost is increased. On the other hand, if the density of the impregnated base paper exceeds 0.6 g / cm ³ , the impregnation property of the water-based thermosetting resin is reduced, and the amount of the water-based thermosetting resin impregnated and applied to the impregnated base paper is reduced. Since it becomes difficult to obtain the desired interlayer strength of the present invention and the impact resistance is lowered, the impregnated base paper cannot be used as a flooring.

The basis weight of the impregnated base paper is 170 to 200 g / m ² , preferably 180 to 195 g / m ² , and more preferably 180 to 190 g / m ² . By setting the basis weight of the impregnated base paper in such a range, the impregnation amount of the water-based thermosetting resin can be set in a range described later. That is, when the basis weight of the impregnated base paper is less than 170 g / m ² , a desired thickness cannot be ensured, and impact resistance tends to decrease. On the other hand, when the basis weight of the impregnated base paper exceeds 200 g / m ² , the ratio of the impregnated amount of the water-based thermosetting resin with respect to the impregnated base paper is reduced, so that it is difficult to obtain the desired interlayer strength of the present invention. Since the impact resistance is lowered, it becomes difficult to use the impregnated base paper as a flooring.

  As described above, the present impregnated base paper has been described with respect to the case where the front layer, the intermediate layer, and the back layer are composed of three paper layers. In addition to this, for example, it may be an impregnated base paper composed of two paper layers, a front layer and a back layer, and further, an intermediate layer of the impregnated base paper is composed of two or more layers, and 4 You may comprise the paper layer more than a layer. That is, the floor material impregnated base paper having a plurality of intermediate layers only needs to have a structure in which all layers including the intermediate layer can be impregnated with the water-based thermosetting resin.

  The above-described impregnated base paper is impregnated and coated with a water-based thermosetting resin to form an impregnated paper for flooring according to the present invention (hereinafter referred to as “the impregnated paper”). That is, the impregnated paper is formed by impregnating and applying an impregnating liquid, which is a water-based thermosetting resin, to all layers constituting the impregnated base paper.

  The impregnated paper formed in this manner has an interlaminar strength (hereinafter simply referred to as “interlaminar strength”) measured according to “Adhesive tape / adhesive sheet test method—tensile strength” described in JIS-Z0237 (2000). Is adjusted so that the length is 350 N / 15 mm or more and the width is 200 N / 15 mm or more. If the longitudinal interlayer strength of the impregnated paper is less than 350 N / 15 mm and the lateral interlayer strength is less than 200 N / 15 mm, delamination tends to occur and impact resistance decreases, so this impregnated paper is used as a flooring. become unable.

The water-based thermosetting resin impregnated and coated on the impregnated base paper has at least a —CH ₂ OH group (methylol group). Thus, the impregnated paper can be used as the core paper for flooring by impregnating and applying the water-based thermosetting resin having at least —CH ₂ OH group to the impregnated base paper. That is, even if soft plywood is used as plywood, even if soft plywood is used, if this impregnated paper is used as the core paper for flooring, the unevenness formed on the surface of the flooring will be covered. Will be able to.

Examples of the water-based thermosetting resin having at least a —CH ₂ OH group include melamine, phenol, urea, DAP, and epoxy resin. Among these, water-based thermosetting resins are preferable. , Melamine, phenol and urea. Among these, it is more preferable to use a melamine resin, because it can provide an impregnated paper having high hardness and high impact resistance.

  Moreover, the impregnation amount of the water-based thermosetting resin in the impregnated paper is 37 to 71%, preferably 40 to 60% with respect to the basis weight of the entire impregnated base paper. If the impregnation amount of the water-based thermosetting resin is less than 37%, the desired interlaminar strength of the present invention cannot be obtained, and delamination tends to occur. Therefore, impregnated paper should be used as a flooring material. It becomes difficult. On the other hand, when the impregnation amount of the water-based thermosetting resin exceeds 71%, since the water-based thermosetting resin is impregnated more than the necessary amount, drying takes time, work efficiency is deteriorated, and the manufacturing cost is high. Problem arises.

Thus, the impregnated base paper formed by impregnating and applying the water-based thermosetting resin having a specific —CH ₂ OH group to the impregnated base paper preferably has a resin permeability of 5 to 13 seconds. Preferably, it is 6 to 11 seconds. If the resin permeability of the impregnated base paper is less than 5 seconds, the impregnation property of the water-based thermosetting resin becomes too high and the water-based thermosetting resin more than the necessary amount is impregnated. As the work efficiency deteriorates, the manufacturing cost increases. On the other hand, when the resin permeability exceeds 13 seconds, the impregnation property of the water-based thermosetting resin becomes low, the time until the required amount of the water-based thermosetting resin is impregnated becomes long, and the operability is lowered. .

  The paper thickness of the impregnated paper is preferably in the range of 550 to 750 μm. As a result, even if this impregnated paper is used as a plywood, the surface property is poor and a soft veneer plywood is used, the interlayer strength is high, it has impact resistance, and is formed on the surface of the flooring. It can be set as the impregnated paper for flooring which can coat | cover an unevenness | corrugation. In order to set the paper thickness of the impregnated paper in the range of 550 to 750 μm, the paper thickness of the impregnated base paper is 400 to 500 μm because swelling occurs after the water-based thermosetting resin is impregnated. Is preferred.

  When the paper thickness of the impregnated paper is less than 550 μm, for example, when a veneer plywood that is soft and has poor surface properties is used as the plywood, impact resistance is lowered and unevenness formed on the surface of the flooring can be covered. Therefore, it becomes difficult to use the impregnated paper as a flooring. In addition, the veneer plywood can be seen by applying the V-cut process, which causes a problem that the appearance as a flooring material is deteriorated and the quality is deteriorated.

  On the other hand, when the paper thickness of the impregnated paper exceeds 750 μm, processability as a flooring material is lowered. Further, in order to make the paper thickness of the impregnated paper larger than 750 μm, it is necessary to increase the paper thickness of the impregnated base paper. However, if the paper thickness of the impregnated base paper is too large, the water-based thermosetting resin is impregnated during the impregnation coating. The time until the thermosetting resin penetrates into the impregnated base paper becomes longer, the operability is lowered, and the amount of the water-based thermosetting resin to be used is increased, so that the production cost is increased. Furthermore, delamination is likely to occur, resulting in a problem that impact resistance is reduced.

  By using this impregnated base paper as described in detail above and forming this impregnated paper, even when a soft veneer plywood with poor surface properties is used as a plywood, the interlayer strength is high and the It is possible to solve the problem of the present invention of providing an impregnated base paper for flooring and an impregnated paper for flooring that have impact properties and can cover unevenness formed on the surface of the flooring.

  In order to confirm the effect of the impregnated paper for flooring according to the present invention, the following various samples were prepared, and a test for evaluating the quality of each sample was performed. In addition, in a present Example, the numerical value which shows a mixing | blending, a density | concentration, etc. is a numerical value of the solid content or the mass reference | standard of an active ingredient. Moreover, since the pulp, chemical | medical agent, etc. which are shown in a present Example are only examples, it cannot be overemphasized that this invention is not restrict | limited by these Examples, and can be selected suitably.

  In order to compare and compare with 22 types of impregnated paper for flooring according to the present invention (referred to as “Example 1” to “Example 22”) and Examples 1 to 22, Impregnated paper for flooring (referred to as “Comparative Example 1” to “Comparative Example 4”) was prepared in the configuration shown in Table 1.

[Example 1]
Using the following raw materials, a four-layer impregnated base material for flooring comprising a surface layer, a back layer, and two intermediate layers located between both layers was obtained according to the following production method.
<Raw material>
・ Surface and back layers After blending 90% by weight of softwood bleached kraft pulp (NBKP) and 10% by weight of mechanical pulp (TMP), the raw material with Canadian Standard Freeness (CSF) adjusted to 550cc is used as a chemical fixing agent. , 0.4% by weight of aluminum sulfate in solid content, wet paper strength enhancer (WS4024 manufactured by Seiko PMC Co., Ltd.) 0.175 mass% in solid content, dry paper strength enhancer (DS4356 manufactured by Seiko PMC Co., Ltd.) 0.2% by mass in solid content and 0.02% by mass of impregnating liquid permeation accelerator (DF6300 manufactured by Seiko PMC Co., Ltd.) in solid content were blended to obtain a raw material pulp slurry for the front and back layers.
・ Intermediate layer After blending 90% by weight of softwood bleached kraft pulp (NBKP) and 10% by weight of mechanical pulp (TMP), the raw material prepared by adjusting the CSF to 550 cc is used as a chemical fixing agent. 0.4% by mass, 0.175% by mass of wet paper strength enhancer (WS4024 manufactured by Seiko PMC Co., Ltd.) and 0.2% by mass of dry paper strength enhancer (DS4356 manufactured by Seiko PMC Co., Ltd.) %, Impregnating liquid permeation accelerator (DF6300 manufactured by Seiko PMC Co., Ltd.) was mixed in an amount of 0.02% by mass to obtain a pulp slurry for an intermediate layer.

Using these raw material pulp slurries, the surface layer, the two intermediate layers, and the back layer paper layer are combined with a circular paper machine, the surface layer weight is 50 g / m ² , and the intermediate layer weight is total the ^{80g / m 2, 53g / m} 2 Paste amount of backing layer, the basis weight of the whole impregnation base paper to obtain a 183 g / ^{m 2} and is 4-ply flooring impregnated base paper (example 1).

  The impregnated base paper thus prepared is impregnated with a resin as shown in Table 1 in the amount of impregnation shown in Table 1 with respect to the basis weight of the entire impregnated base paper to form an impregnated paper.

  Further, impregnated base papers were produced in the same manner as in Example 1 except that Examples 2 to 22 and Comparative Examples 1 to 4 were the conditions shown in Table 1. In addition, as the thermally foamable particles in this example, thermally foamable particles (“Matsumoto Microsphere F-46” manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) and a fixing agent (“Haktron KC100” manufactured by Hakuto Co., Ltd.) (aggregated cation) Functional polymer resin).

  In addition, "CSF (cc)" in Table 1 is measured in accordance with "Paper and paperboard-Pulp freeness test method-Canadian standard freeness test method" described in JIS-P8121 (1995). It is the value.

In addition, “attachment amount (g / m ² )” refers to the delamination of each sample, and the basis weight of each layer was measured according to “paper and paperboard—basis weight measurement method” described in JIS-P8124. Value.

  The delamination was performed according to the following procedure. First, each sample obtained from each sample is immersed in water at room temperature for about 1 hour. Each sample immersed in water is wound around a round bar of about 10 mmΦ starting from a corner, and then the round bar is rolled to squeeze each sample. This operation is repeated starting from all four corners of each sample, and the ironing force is applied to the sample from each direction. As a result, a part of the layers of each sample is peeled off, and this is used to separate the layers into a surface layer, an intermediate layer, and a back layer. After delamination, each layer of each sample was sufficiently dried with a hot air dryer or the like and used for the test.

  Table 2 shows the results of quality evaluation for all of these Examples and Comparative Examples. This quality evaluation test was performed under environmental conditions of temperature 23 ± 2 ° C. and humidity 50 ± 2% in accordance with JIS-P8111.

In addition, “basis weight (g / m ² )” in Table 2 is the basis weight of all the layers of each sample, that is, the entire impregnated base paper for flooring, and is described in “Paper and paperboard” described in JIS-P8124 (1998). It is the value measured based on "basis weight measuring method".

  “Paper thickness (μm)” is a value obtained by measuring impregnated base paper and impregnated paper in accordance with “Paper and paperboard—Test method of thickness and density” described in JIS-P8118 (1998).

“Density (g / cm ³ )” means the basis weight of the impregnated base paper measured according to “Paper and paperboard—basis weight measurement method” described in JIS-P8124 (1998), and JIS-P8118 (1998). It is a value calculated from the paper thickness of the impregnated base paper measured according to “Paper and paperboard—Test method of thickness and density” described in 1.

  “Crem water absorbency (mm)” is the value of the water absorbency in the longitudinal direction of the impregnated base paper measured according to “paper and paperboard—water absorbency test method—Klem method” described in JIS-P8141 (2004). is there.

  "Oil absorption (seconds)" TAPPI No. It is a numerical value measured using light oil as a solvent to be dropped in accordance with “Paper—Water Absorption Test Method—Part 2: Dropping Method” described in 32-2 (2000).

  “Resin permeability (seconds)” is the same as “Oil absorption (seconds)” described above. TAPPI No. In accordance with “Paper—Water Absorption Test Method—Part 2: Dropping Method” described in 32-2 (2000), water melamine resin made by Nippon Carbide Co., Ltd. It is a numerical value measured using a melamine resin solution adjusted to a concentration of 50%.

  The “peel strength (MPa)” is a value obtained by measuring the impregnated base paper according to the burst strength test method using “Paper and paperboard-Mullen high pressure tester” described in JIS-P8131 (1995). It is what.

  “Resin permeability (seconds)” is an evaluation of the permeability (impregnation) of a water-based thermosetting resin. TAPPI No. 41 (2000) is a value obtained by measuring impregnated paper in accordance with “Paper and paperboard—oil repellency test method—kit method”.

  “Interlaminar strength (longitudinal) (N / 15 mm)” is a longitudinal interlaminar measurement of impregnated paper according to “Adhesive tape / adhesive sheet test method—tensile strength” described in JIS-Z0237 (2000). In terms of strength, “interlaminar strength (horizontal) (N / 15 mm)” refers to the width of an impregnated paper measured according to “Adhesive tape / adhesive sheet test method—tensile strength” described in JIS-Z0237 (2000). It is a value measured by changing the unit to N / 15 mm because the test piece is 15 mm wide in terms of interlayer strength in the direction.

“Bending” is an evaluation of the interlaminar strength of the impregnated paper. Each sample, which is the impregnated paper, was bent at 90 ° and 180 °, and the occurrence of cracks was visually confirmed and evaluated. The evaluation criteria were as follows.
○: No crack occurred.
○ △: Cracks are starting to occur.
Δ: Slightly cracked.
X: Cracking has occurred.

“Cellophane tape” evaluates the surface strength of the impregnated paper. A cellophane tape having a width of 15 mm and a length of 150 mm is applied to the impregnated paper in the vertical direction, and a 5 kg load is applied for 5 minutes. The peeled surface of the cellophane tape when the cellophane tape was peeled off was observed and evaluated. The evaluation criteria were as follows.
○: The cellophane tape is peeled cleanly.
Δ: The impregnated paper surface is slightly peeled off.
X: The impregnated paper surface and the fibers are peeled off together.

  “Cross-cut” is an evaluation of the interlaminar strength of the impregnated paper. The evaluation method is to use a grid with a width of 2 mm and a depth of 0.3 mm vertically and horizontally in the flow direction of the surface of the impregnated paper impregnated with the impregnated base paper as each sample, and cut with a 100 mm cutter. Then, a cellophane tape was applied to the surface of the impregnated paper, and then the cellophane tape was forcibly removed. In this case, the evaluation was performed by counting the cells where the layers were not separated. In the table, it is expressed as “the number of remaining wrinkles / 100 wrinkles”.

“Comprehensive evaluation” is a comprehensive evaluation of resin permeability, interlaminar strength (vertical / horizontal), bending, cellophane tape, and grid, and the evaluation criteria are as follows. .
A: Satisfactory.
○: Satisfied.
Δ: Slightly satisfactory
X: Not satisfied.

From Table 2, it can be seen that the floor material impregnated paper according to the present invention has high interlayer strength, impact resistance, and can cover the unevenness formed on the surface of the floor material.

Claims (4)

In an impregnated base material for flooring of a multilayer paper having at least two layers of a surface layer and a back layer,
In the raw material pulp constituting each layer of the impregnated base paper for flooring, 10 to 20% by mass of mechanical pulp is blended, and 80 to 90% by mass of NBKP is blended,
The raw pulp is adjusted to a freeness of 550 to 750 cc according to “Paper and paperboard—Pulp freeness test method—Canadian standard freeness test method” described in JIS-P8121 (1995). And
The paper thickness is 400-500 μm ,
The density measured according to “Paper and paperboard—Test method for thickness and density” described in JIS-P8118 (1998) is 0.3 to 0.6 g / cm ³ ,
The Klem water absorption measured in accordance with “Paper and paperboard—Water absorption test method—Klem method” described in JIS-P8141 (2004) is 80 to 97 mm,
In addition, J.H. TAPPI No. 41 (2000), the oil absorption measured in accordance with “Paper and paperboard—oil repellency test method—kit method” is 1.3 to 1.8 seconds,
An impregnated base paper for flooring, which is impregnated with a water-based thermosetting resin having at least —CH ₂ OH groups (methylol groups).   The impregnating base paper for flooring according to claim 1, wherein an impregnating liquid penetration accelerator is added to the impregnating base paper for flooring.   An impregnated paper for flooring formed by impregnating and applying the aqueous thermosetting resin to the impregnated base paper for flooring according to claim 1 or 2 is disclosed in “Adhesive tape” according to JIS-Z0237 (2000). -Interlaminar strength measured in accordance with "Adhesive sheet test method-Tensile strength" is vertical: 350 N / 15 mm or more and horizontal: 200 N / 15 mm or more.   The impregnated paper for flooring according to claim 3, wherein the paper thickness is 550 to 750 μm.