Snow-resistant paper

Abstract

To provide a snow-resistant paper that is prevented from degradation of a paper due to moisture such as snow and rain, has improved durability, and can be easily discarded and recycled as a used paper and a toy using this snow-resistant paper.SOLUTION: By using a snow-resistant paper having at least on one side of a paper substrate coated with a 1-20 g / m2 of a snow-resistant resin layer, degradation of a paper due to moisture such as snow and rain can be prevented and maintaining strengths even in a time of use in a snow mountain has become possible regardless of being paper-made, thus paper products and toys having excellent durability to snow can be provided. Also, even after using, it can be recycled as a used paper like a normal paper.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to snow-resistant paper in which a snow-resistant resin layer is coated on a paper base material. [Background technology]

[0002] Traditionally, playground equipment such as sleds, skis, and snowboards have been widely known as playground equipment for sliding down slopes such as snowy mountains. Most of these playground equipment are required to be made from materials that are highly resistant to snow, and are therefore made from durable materials such as resin, wood, and metal. However, since these materials make it difficult to change their shape, they pose a problem of requiring a considerable amount of storage space, even though they are only used in the winter season. In addition, disposal of these equipment due to deterioration and other factors places a heavy burden on the environment, and recycling is difficult.

[0003] On the other hand, from spring to autumn, cardboard sheets are sometimes used as play equipment for sliding on slopes without snow, such as grass or meadows. Although cardboard sheets are made of paper and can be recycled as waste paper, they pose a safety problem when sliding on wet slopes due to weather conditions such as rain or fog, as the cardboard sheets can absorb water from the surface of the grass and be damaged during sliding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-240765 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-172696 [Patent Document 3] Japanese Patent Publication No. 2022-058232 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of this situation, the present invention aims to provide snow-resistant paper that prevents deterioration of paper due to moisture such as snow and rain by providing a snow-resistant resin layer on a paper base material, improves durability, and can be easily disposed of and recycled as waste paper after use, as well as play equipment that uses this snow-resistant paper. [Means for solving the problem]

[0006] The present invention includes, but is not limited to, the following aspects. [1] Snow-resistant paper characterized in that a snow-resistant resin layer is coated on at least one side of a paper base material. [2] The coating weight of the snow-resistant resin layer is 1 to 20 g / m 2 The snow-resistant paper according to [1]. [3] The snow-resistant resin layer is made of at least one of styrene resin, acrylic resin, and polyolefin resin. Snow-resistant paper according to [1] or [2], containing one of the above and wax. [4] A method for producing snow-resistant paper according to any one of [1] to [3], comprising a step of coating a snow-resistant resin layer on at least one side of a paper substrate. [5] A box comprising the snow-resistant paper described in any one of [1] to [3]. [6] A cardboard sheet comprising the snow-resistant paper according to any one of [1] to [3]. [7] A paper product made using the snow-resistant paper described in any one of [1] to [3]. [8] A paper product made using the cardboard sheet described in [6]. [9] The paper product according to [7] or [8], which is a paper playground equipment.

[10] A paper processed product according to [7] or [8], which is a paper building.

[11] The paper product according to [7] or [8], which is paper furniture. [Effects of the Invention]

[0007] The present invention provides snow-resistant paper that can prevent deterioration of paper due to moisture such as snow and rain by coating at least one side of a paper base material with a snow-resistant resin layer. Furthermore, the present invention can provide paper products and play equipment that are highly resistant to snow because they can maintain their strength even when used on snowy mountains, etc., despite being made of paper. [Brief explanation of the drawings]

[0008] [Figure 1] This is a photograph showing the use of a paper playground equipment (sled) according to one embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a paper building (tent) according to one embodiment of the present invention. [Figure 3] FIG. 1 is a perspective view of a paper furniture (table) according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The snow-resistant paper according to this embodiment will be described below.

[0010] The present invention relates to snow-resistant paper characterized by having a snow-resistant resin layer coated on at least one side of a paper base material. The snow-resistant paper of the present invention can be used for a wide range of purposes, including winter snow mountain leisure activities, agriculture, disaster evacuation facilities, furniture, and transportation, without any particular limitations, such as for sliding equipment such as sleds, skis, and snowboards, buildings to protect against snowfall such as tents and greenhouses, furniture that can be easily placed on snow such as tables and chairs, and the transportation of snow products such as snowmen.

[0011] The type of paper used for the snow-resistant paper of the present invention is not particularly limited, and may be appropriately selected from wrapping paper, processed base paper, corrugated cardboard base paper, paperboard for paper containers, miscellaneous paperboard, thick paper, etc. The basis weight of the snow-resistant paper of the present invention is not particularly limited, but may be, for example, 30 to 800 g / m 2 When the paper base material is a multi-layer paper having two or more paper layers, the basis weight of the snow-resistant paper is 75 to 750 g / m 2 or 100-700g / m 2 , and even 200-600g / m2 It can be said that:

[0012] In a preferred embodiment, the snow-resistant paper of the present invention has a surface Cobb water absorbency of 3 g / m2 at 120 seconds. 2 less than 2 g / m 2 Less than 1g / m is more preferable. 2 It may be 1 g / m or less when measuring the 120-second Cobb water absorbency. 2 In a preferred embodiment, in the case of paper having a 30-minute Cobb water absorbency of 25 g / m2 or less (including cases where the paper does not absorb water and is below the measurement limit), 2 less than 20 g / m 2 Less than 10 g / m is more preferable. 2 In the present invention, the Cobb water absorbency is measured in accordance with the Cobb method specified in JIS P8140, by contacting 100 ml of distilled water with the coating layer and measuring the weight of water absorbed per unit area after a specified time. The smaller the Cobb water absorbency value, the higher the snow resistance of the snow-resistant paper.

[0013] In a preferred embodiment, the snow-resistant paper of the present invention is also excellent in moisture resistance, with a moisture permeability of 100 g / m 2 24 hours or less is preferable, 75 g / m 2 24 hours or less or 50g / m 2 The moisture permeability of snow-resistant paper can be measured from the coating layer side in accordance with JIS Z 0208, and the smaller the value, the higher the moisture resistance.

[0014] In a preferred embodiment, the snow-resistant paper of the present invention also has excellent oil resistance, and the oil repellency of the coating layer side is preferably kit number 7 or higher, and may be kit number 8 or higher or kit number 9 or higher. Here, the oil repellency of snow-resistant paper can be measured from the coating layer side in accordance with "Paper and Paperboard - Oil Repellency Testing Method - Kit Method" (JAPAN TAPPI Paper and Pulp Testing Method No. 41), and the higher the kit number, the higher the oil resistance.

[0015] The snow-resistant paper of the present invention preferably has an Oken smoothness of 15 seconds or more on the coated surface, more preferably 20 seconds or more, and even more preferably 25 seconds or more. When the smoothness of the surface of the coating layer of the snow-resistant paper is in the above range, the surface of the coating layer has a high gloss, which not only provides excellent aesthetic appeal but also allows the paper to be used as a slide for smooth sliding on snowy slopes. In a preferred embodiment, the snow-resistant paper of the present invention is processed into a corrugated cardboard sheet. The thickness of the corrugated cardboard sheet is not particularly limited and can be appropriately set depending on the application, processing suitability, and function, but in a preferred embodiment, the thickness of the corrugated cardboard sheet is 0.2 to 15 mm, more preferably 0.4 to 5 mm.

[0016] Corrugated cardboard sheets are made by gluing together flat paper (liner) and corrugated paper (core) with adhesive, and are suitable for a variety of uses, such as packaging and cushioning for products, transporting luggage, storing goods, etc. As mentioned above, corrugated cardboard sheets can also be appropriately cut, assembled, glued, and otherwise processed for use in sliding equipment, buildings, furniture, etc.

[0017] The corrugated cardboard sheet according to the present invention can generally be produced by bonding a liner and a corrugated medium together using a corrugator. Any known corrugator can be used without limitation, but a typical corrugator is composed of a single facer, a double backer, and a cutter. A glue-making device for bonding the liner and medium base paper, as well as a device for generating heat to melt the glue, are also used.

[0018] Furthermore, when manufacturing the corrugated cardboard sheet according to the present invention, an adhesive is used to bond the liner and the corrugating medium. While known adhesives can be used, it is preferable to use a water-resistant adhesive, as this prevents the strength of the corrugated cardboard box from being reduced by water wetting, condensation, and humidity on the cross section of the corrugated cardboard sheet. A water-resistant adhesive is a standard corrugated cardboard adhesive to which a water-resistant agent has been added. The water-resistant agent is not particularly limited, and examples include those containing synthetic resin emulsions, ketone aldehyde resins, etc.

[0019] The liner used for the cardboard sheet will be described later, but depending on the application and the part to be used, kraft liner, jute liner, etc. can be used. The basis weight of the liner is not particularly limited, and for example, the basis weight of the entire liner can be 70 to 550 g / m 2 and can be set to 100 to 500 g / m 2 Or 150~450g / m 2 It may also be possible to use the following.

[0020] The corrugating material that makes up the cardboard can be A-flute, B-flute, C-flute, E-flute, F-flute, G-flute, AAA-flute, AA-flute, W-flute, etc., depending on the application and the part to be used, but as mentioned above, by selecting the configuration of the corrugating material so that the overall thickness of the cardboard sheet can be reduced, the temperature adaptability to the surrounding environment in which the paper container is placed will be good and loading efficiency will also be improved. There are also no particular restrictions on the basis weight of the corrugating material, and it is recommended to use a material with a weight of 120 g / m. 2 , 160g / m 2 , 180g / m 2 , reinforced 180g / m 2 , reinforced 200g / m 2 It is preferable to reduce the basis weight of the liner and / or the medium within a range that ensures the effects of the present invention and that ensures the strength of the paper container at a certain level or above.

[0021] Various processed products using the snow-resistant paper of the present invention can be produced from a single blank sheet of corrugated cardboard by folding it and, if necessary, bonding it with an adhesive. The type of adhesive is not particularly limited, and examples include water-based, water-dispersed, solution-based, solventless, and solid-based adhesives, and can be selected appropriately depending on the surface condition of the paper material to be bonded.

[0022] The amount of adhesive used is not particularly limited as long as sufficient adhesive strength is obtained, but in the case of surface application, it is 0.5 to 2000 g / m 2 It can be 5 to 1500 g / m2 It may be 10 to 1000 g / m 2 In the case of line application, the application width can be changed appropriately depending on the nozzle diameter of the applicator, the movement speed of the nozzle or paper material, the viscosity of the adhesive during application, the width of the paper to be adhered, etc., and the application amount per unit length is not particularly limited, but may be, for example, 0.1 to 30 g / m, 0.5 to 20 g / m, or 1 to 15 g / m.

[0023] paper base material The snow-resistant paper of the present invention has at least a paper base material and a snow-resistant resin layer coated on at least one side of the paper base material. In the present invention, the basis weight of the paper base material is not particularly limited, and is, for example, 50 to 800 g / m 2 The paper substrate used in the present invention is preferably a multi-layer paperboard having two or more paper layers, and has a basis weight of 70 to 800 g / m², from the viewpoint of having sufficient strength when processed into paper boxes, various play equipment, building materials, and furniture. 2 For example, in the case of a cardboard liner, the basis weight is set to 80 to 600 g / m 2 It can be set in the range.

[0024] In a preferred embodiment, the paper substrate used in the present invention has a 120-second Cobb water absorbency of 40 g / m on the side on which the snow-resistant resin layer is to be formed. 2 More preferably, it is 30 g / m or less. 2 or less, more preferably 25 g / m 2 Below 20 g / m, most preferably 2 In a preferred embodiment, the paper substrate used in the present invention has a 120-second Cobb water absorbency of 5 g / m 2 More preferably, it is 7 g / m or more. 2 More preferably, 10 g / m 2In the present invention, the Cobb water absorbency of the paper base material can be adjusted by coating a snow-resistant resin layer, etc., and by ensuring that the 120-second Cobb water absorbency of the paper base material is in the above-mentioned range, a decrease in paper strength due to excessive penetration of water contained in the solvent of the snow-resistant paint is prevented, and the solid content of the snow-resistant paint remains on the surface of the paper layer, providing reliable coverage and improving snow resistance.

[0025] In a preferred embodiment, the paper substrate used in the present invention has a water repellency of R4 or higher, more preferably R6 or higher, and even more preferably R8 or higher, as measured in accordance with JAPAN TAPPI Paper and Pulp Testing Method No. 68, "Paper and Paperboard - Water Repellency Testing Method." If the paper substrate has a water repellency of R4 or higher, when a water-resistant agent is applied, the water contained in the coating solution does not penetrate excessively into the paper substrate, making it easier to prevent a decrease in paper strength.

[0026] In a preferred embodiment, the paper substrate used in the present invention has an oil drop absorbency of 5 seconds or more on the surface on which the snow-resistant resin layer is to be formed, more preferably 7 seconds or more, and even more preferably 10 seconds or more. There is no particular upper limit, but it is preferably 80 seconds or less, more preferably 75 seconds or less, and even more preferably 70 seconds or less. Having an oil absorbency within the above range allows the snow-resistant resin layer to remain on the paper surface and not easily penetrate into the paper layer, making it easier to improve snow resistance. The oil absorbency of a paper substrate can be evaluated by using a microsyringe equipped with an H5 needle to drop a drop of diesel No. 1, whose dynamic viscosity has been adjusted to 3 cSt, onto the sample surface, and measuring the time it takes for the surface gloss to disappear.

[0027] The physical properties of the paper substrate are not particularly limited and can be set appropriately depending on the application of the snow-resistant paper. In the present invention, for example, the longitudinal elongation is 1.0 to 15.0%, the transverse elongation is 2.0 to 12.0%, and the specific compressive strength is 100 to 350 N·m 2 / g, specific burst strength 2.80~5.00kPa·m 2 / g.

[0028] In a preferred embodiment, the paper substrate used in the present invention has an Oken smoothness of 10 seconds or more on the surface on which the coating layer is to be formed, more preferably 13 seconds or more, and even more preferably 16 seconds or more. There is no particular upper limit, but it is preferably 100 seconds or less, more preferably 90 seconds or less, even more preferably 80 seconds or less, and most preferably 70 seconds or less. By having the smoothness of the surface on which the snow-resistant resin layer is to be formed within the above range, it becomes easier to uniformly coat the paper substrate with the snow-resistant resin layer, and excellent snow-resistant paper can be obtained.

[0029] In a preferred embodiment, the paper substrate used in the present invention has a moisture permeability of 1500 g / m 2 measured from the side where the snow-resistant resin layer is provided. 2 24 hours or more, preferably 1750 g / m 2 24 hours or more, preferably 2000g / m 2 The upper limit of the moisture permeability is not particularly limited, but in a preferred embodiment, it is 5000 g / m 2 24 hours or less, preferably 4500g / m 2 24 hours or less, more preferably 4000g / m 2 When the moisture permeability of the surface on which the snow-resistant resin layer is to be formed is within the above range, the moisture in the coating agent is efficiently evaporated to the paper layer side during the drying process after coating, making it easier to uniformly coat the paper base material with the snow-resistant resin layer.

[0030] In a preferred embodiment, the paper substrate used in the present invention has a water contact angle of 70° or more, more preferably 75° or more, on the surface on which the snow-resistant resin layer is to be formed. Having a water contact angle in the above range prevents excessive penetration of water contained in the coating liquid into the paper substrate, and prevents a decrease in the strength of the paper substrate.

[0031] The raw material pulp for the paper base material can be any known pulp without any particular limitation. Specific examples include various wood-derived pulps 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 chemithermomechanical pulp (CTMP), as well as non-wood pulps obtained from kenaf, bagasse, bamboo, hemp, straw, etc.

[0032] The paper base material may contain recycled paper pulp, or it may not contain recycled paper pulp. When recycled paper pulp is contained, for example, when the paper base material is a single-ply paper, the recycled paper pulp content of the total pulp is preferably 10% by mass or more, more preferably 25% by mass or more, even more preferably 50% by mass or more, and most preferably 70% by mass or more, or it may be 100% by mass (consisting only of recycled paper-derived pulp). Kraft pulp may also be blended as a pulp other than recycled paper pulp, or the entire amount may be kraft pulp. When the paper base material is a multi-layer paperboard having two or more paper layers, the recycled paper pulp content per layer may be as described above, and the recycled paper pulp content in each layer may be different.

[0033] Examples of waste paper pulp that can be used include waste paper pulp obtained by disintegrating unprinted waste paper such as cardboard, white paper, extra white paper, medium white paper, and white damage; printed waste paper such as fine paper, fine coated paper, medium paper, medium coated paper, and recycled paper; written waste paper; paper such as discarded confidential documents; and deinked pulp (DIP) obtained by disintegrating waste magazines and newspapers.

[0034] In addition, in the papermaking process for paper substrates, sizing agents and water repellents can be added internally or externally, and a paper strength agent can be added internally to improve strength. Examples of sizing agents include rosin-based sizing agents, rosin emulsion-based sizing agents, α-carboxymethyl saturated fatty acids, neutral rosin-based sizing agents, alkyl ketene dimers (AKD), alkenyl succinic anhydrides (ASA), and cationic polymer-based sizing agents. Examples of water repellents include fluorine-based resins, polyamide-based resins, and waxes. Examples of paper strength agents include conventionally used paper strength agents such as polyacrylamide (PAM) and modified starch. In the present invention, it is preferable to incorporate wax into the snow-resistant resin layer, and paraffin-based wax is more preferable.

[0035] Furthermore, known fillers can be added to the paper substrate as needed, and inorganic and organic fillers can be used without restriction. Examples of inorganic fillers include kaolin, calcined kaolin, delaminated kaolin, clay, calcined clay, delaminated clay, illite, heavy calcium carbonate, light calcium carbonate, light calcium carbonate-silica composite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, and zinc hydroxide. Examples of organic fillers include urea-formalin resin, polystyrene resin, and phenolic resin.

[0036] Furthermore, aluminum sulfate, aluminum chloride, sodium aluminate, basic aluminum compounds, water-soluble aluminum compounds, polyvalent metal compounds, silica sol, etc. may be added internally to the extent that the quality of the paper base is not affected.

[0037] The paper substrate can be produced by a known papermaking method, for example, using a Fourdrinier paper machine, a gap former paper machine, a hybrid former paper machine, an on-top former paper machine, a cylinder paper machine, or the like, but is not limited to these.

[0038] Furthermore, to adjust the smoothness of the paper base material of the present invention, a smoothing treatment may be carried out as necessary. For the smoothing treatment, a smoothing treatment device such as a normal calender, super calender, gloss calender, soft calender, thermal calender, or shoe calender can be used. The smoothing treatment device may be adjusted as appropriate by adjusting the shape of the pressure device, the number of pressure nips, heating, line pressure, etc.

[0039] Snow-resistant resin layer The snow-resistant paper of the present invention has a snow-resistant resin layer on at least one side of a paper substrate. The snow-resistant resin layer of the present invention contains a synthetic resin and a wax. The synthetic resin preferably contains at least one of a styrene-based resin, an acrylic-based resin, and a polyolefin-based resin. In particular, the synthetic resin is preferably a styrene-based resin and / or an acrylic-based resin.

[0040] The styrene-based resin that can be contained in the snow-resistant resin layer preferably has a copolymerization ratio of 50 mass% or more of a styrene-based monomer having a styrene skeleton in its structure, and may be composed only of a polymer of a styrene-based monomer.

[0041] Examples of styrene-based monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, and α-methyl-p-methylstyrene.

[0042] Examples of monomers copolymerizable with styrene monomers include alkyl methacrylates such as methyl methacrylate, cyclohexyl methacrylate, and methylphenyl methacrylate, alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and cyclohexyl acrylate, unsaturated carboxylic acids such as methacrylic acid and acrylic acid, unsaturated dicarboxylic anhydrides such as maleic acid and itaconic acid, unsaturated nitriles such as acrylonitrile and methacrylonitrile, and conjugated dienes such as 1,3-butadiene and 2-methyl-1,3-butadiene. These can be used alone or in combination of two or more.

[0043] The acrylic resin that can be contained in the snow-resistant resin according to the present invention is a resin in which the copolymerization ratio of acrylic acid, methacrylic acid, and acrylic monomers that are derivatives thereof is 50% by mass or more, and may be composed only of polymers of acrylic monomers.

[0044] Examples of acrylic monomers include methacrylic acid esters such as cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, and methyl methacrylate, and acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and isopropyl acrylate, and the acrylic resin may be a polymer of one or more monomers selected from these acrylic monomers.

[0045] Examples of monomers copolymerizable with acrylic monomers include aromatic vinyl compounds such as styrene, o-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, and α-methyl-p-methylstyrene, unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, unsaturated dicarboxylic anhydrides such as maleic anhydride, and unsaturated carboxylic acids such as methacrylic acid and acrylic acid. These may be used alone or in combination of two or more.

[0046] The snow-resistant resin layer according to the present invention preferably has a melting point of 65° C. or higher, more preferably 70° C. or higher, and even more preferably 75° C. or higher. There are no particular limitations on the upper limit of the melting point of the snow-resistant resin layer, but it is preferably 200° C. or lower, more preferably 190° C. or lower, and even more preferably 180° C. or lower. When the melting point of the snow-resistant resin layer is within these ranges, the snow-resistant resin melts during hot-melt bonding, improving the adhesive effect of the hot-melt adhesive and allowing for strong bonding.

[0047] The snow-resistant resin layer according to the present invention preferably has a glass transition point of not more than 55° C., more preferably not more than 50° C., and even more preferably not more than 45° C. When the snow-resistant resin layer has a glass transition point within the above range, the waterproof resin layer does not crack and can maintain its waterproof properties not only in a refrigerated (0 to 10° C.) environment but also in a household refrigerator or in a frozen (-20 to 0° C.) environment during transportation.

[0048] The snow-resistant resin layer according to the present invention contains a wax. Examples of waxes that may be contained in the snow-resistant resin layer include synthetic waxes such as polyethylene wax, Fischer-Tropsch wax, oil-based synthetic waxes (fatty acid esters, fatty acid amides, ketones, and amines), and hydrogenated oils, as well as natural waxes such as beeswax, Japan wax, paraffin wax, and microcrystalline wax. These waxes may be used alone or in combination of two or more, with paraffin-containing hydrocarbon waxes being particularly preferred.

[0049] In the present invention, a pigment may be incorporated into the snow-resistant resin layer for purposes such as improving whiteness. In this case, the incorporation of the pigment preferably increases the surface whiteness by 1% or more compared to the whiteness of the paper substrate. Examples of such pigments include inorganic pigments such as calcium carbonate, titanium oxide, kaolin, clay, engineered kaolin, delaminated clay, talc, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicates, colloidal silica, satin white, mica, and montmorillonite. These pigments can be used alone or in combination of two or more. Among these pigments, kaolin, calcium carbonate, or mica, which have flat particles, are particularly suitable because they do not impair waterproofing. Such flat-shaped inorganic pigments preferably have an aspect ratio of 10 or greater. The pigment content in the snow-resistant resin layer is preferably 5 to 40% by mass, more preferably 10 to 35% by mass. If the pigment content is 5 to 40% by mass, it is easy to effectively improve the whiteness without significantly impairing the waterproof property.

[0050] The snow-resistant resin layer according to the present invention is characterized by containing an antifoaming agent. The inclusion of an antifoaming agent suppresses the formation of minute swellings and bubbles (hereinafter also referred to as "blisters") that tend to form on the surface of the coating layer when the coating agent is applied and dried, thereby ensuring reliable coverage of the paper substrate with the waterproof resin layer and further improving waterproofing. The type of antifoaming agent can be selected appropriately depending on the components of the snow-resistant resin. However, when applying a snow-resistant resin primarily composed of a styrene-acrylic resin, it is preferable to use an antifoaming agent containing at least one of mineral oil, polyether, and silica. The amount of antifoaming agent added is preferably 0.05 to 6.0 parts by weight, more preferably 0.1 to 5.0 parts by weight, and even more preferably 0.15 to 4.0 parts by weight, per 100 parts by weight of the snow-resistant resin.

[0051] The snow-resistant resin layer according to the present invention may contain, for example, a binder, a stabilizer, a viscosity modifier, a water-retaining agent, a preservative, a colorant, etc. The snow-resistant resin layer according to the present invention can be formed by applying a paint to a paper substrate and drying it. The coating amount of the snow-resistant resin layer is 1 to 20 g / m 2 It is preferable to set the thickness to 4 to 15 g / m 2 It is more preferable to set the thickness to 20 g / m 2 If the temperature exceeds this range, further improvement in waterproofness cannot be expected, and the manufacturing cost may increase.

[0052] In a preferred embodiment, the snow-resistant resin layer provided on the snow-resistant paper of the present invention has an average thickness of 5.5 to 20 μm, more preferably 5.6 to 15 μm, and even more preferably 5.7 to 12.5 μm. Here, the average thickness of the coating layer is the average value of the thicknesses of the snow-resistant resin layer measured by cutting a sample into strips and observing the cross sections at any 10 points using an electron microscope.

[0053] The snow-resistant paper of the present invention has a moisture permeability of 15 (g / m) per unit thickness of the snow-resistant resin layer. 2 24h) / μm or less is preferable, and 10 (g / m 2 24h) / μm or less is more preferable, and 7 (g / m 2 ·24h) / μm or less is even more desirable. Here, the moisture permeability per unit thickness of the snow-resistant resin layer is calculated by dividing the moisture permeability measured from the coating layer side of the waterproof paper in accordance with JIS Z 0208 by the average coating layer thickness.

[0054] The snow-resistant paper of the present invention can be produced by coating at least one surface of a paper substrate with a snow-resistant resin and drying the coating. The snow-resistant resin layer can be formed by applying a coating agent using a known coating method, such as air knife coating, curtain coating, blade coating, gate roll coating, or die coating. The coating layer may be a single layer or multiple layers, and multiple coating layers may be applied sequentially, or two or more layers may be applied simultaneously using curtain coating or the like. When drying the coating layer, the temperature of the coating layer at the exit of the drying process is preferably adjusted to be less than 120°C. The coating speed when applying the coating agent can be appropriately set taking into account the viscosity of the coating agent and the target coating weight.

[0055] In a preferred embodiment, the snow-resistant resin layer is applied to the paper substrate by a contour coating method such as air knife coating or curtain coating, which ensures a uniform amount of coating agent applied to the paper substrate surface, resulting in a uniform coating film thickness and preventing blistering in the coating layer during the subsequent drying process. Furthermore, the amount of coating agent used can be reduced compared to contact coating methods, thereby reducing production costs.

[0056] The snow-resistant resin layer coated on the paper substrate is dried. In this drying process, the coating temperature at the exit is preferably less than 120°C, and may be adjusted to 100°C or less. If the coating temperature at the exit is 120°C or higher, the incidence of blisters in the coating may increase, and blocking may occur on the paper wound after the coating layer has been formed. On the other hand, the coating temperature at the exit is preferably 60°C or higher, more preferably 70°C, and can also be 80°C or higher. If the coating temperature at the exit is less than 60°C, not only may blocking occur on the paper wound after the coating layer has been formed, but the coating may not dry sufficiently, resulting in insufficient waterproof performance.

[0057] The coating temperature at the drying process exit can be set taking into account the basis weight and thickness of the paper substrate. For example, when the paper substrate is a multi-layer paperboard and serves as a corrugated cardboard liner with a high basis weight and thickness, blisters tend to form on the surface of the coating layer compared to kraft paper, which is a single-ply paper with a relatively low basis weight and thickness. The reason for this is not limited, but corrugated cardboard liners often have a higher basis weight and thickness and lower air permeability than kraft paper. Even if the moisture content of the paper is the same as that of kraft paper, it is thought that blisters are more likely to form on the surface of the coating layer because much of the moisture evaporated inside the paper substrate during the drying process cannot escape sufficiently. For this reason, the higher the basis weight and thickness of the paper substrate, the lower the coating temperature at the drying process should be within the above range. Here, the "exit of the drying process" refers to the exit of the drying zone if there is one drying zone in the drying process. If there are multiple drying zones in the drying process, it refers to the exit of the most downstream drying zone.

[0058] The temperature of the coating layer at the exit of the drying process can be adjusted by adjusting the drying time and the temperature of the drying zone. The drying time is determined by the paper substrate feed speed, the number and length of drying zones, and the equipment capacity of the drying zones (air volume, infrared output), etc. Furthermore, any known drying method can be used, such as a steam cylinder heating drying method, a hot air drying method, a gas-type infrared drying method, or an electric infrared drying method. Any one of these methods can be used alone or in combination of two or more. [Example]

[0059] The present invention will be described in more detail below using specific examples, but the present invention is not limited to the following specific examples. In this specification, unless otherwise specified, concentrations and the like are based on weight, and numerical ranges include their endpoints.

[0060] Liner and corrug base paper manufacturing (1) Liner sample A A back layer made of 100% recycled corrugated paper pulp, a middle layer made of 100% recycled paper pulp, and a top layer made of 70% unbleached kraft pulp and 30% recycled corrugated paper pulp were combined in a weight ratio of back layer: middle layer: top layer = 25:60:15. After drying with a dryer, a water repellent agent containing paraffin wax and rosin was applied to one side of the top layer. After drying with a dryer again, the surface was smoothed using a calender to produce liner sample A (basis weight: 282.6 g / m). 2 , 120-second Cobb water absorption of the surface: 12.9 g / m 2 , Water repellent coating amount: approx. 1g / m 2 ). (2) Liner sample B A waterproofing agent consisting of 100 parts styrene-acrylic resin (Michaelman MC1548A) and 5 parts wax emulsion (Seiko PMC WR3932) was applied to the surface of liner sample A using an air knife at a rate of 10.0 g / m. 2 The coating was applied and then dried with hot air so that the temperature of the coating layer at the exit of the drying process was 80°C, to obtain liner sample B (basis weight: 291.4 g / m 2 , 120-second Cobb water absorption of the surface: 0.1 g / m 2 ). (3) Liner sample C A back layer made of 100% recycled corrugated paper pulp, a middle layer made of 100% recycled paper pulp, and a surface layer made of 70% unbleached kraft pulp and 30% recycled corrugated paper pulp were combined in a weight ratio of back layer:middle layer:surface layer = 25:60:15. After drying in a dryer, the surface was smoothed using a calender to produce liner sample C (basis weight: 281.3 g / m 2 , 120-second Cobb water absorption of the surface: 27.7 g / m 2 ). (4) Liner sample D A 10 μm thick polyethylene film was laminated on the surface of liner sample C, and then the film was adhered and laminated using a roller heated to 80°C to obtain liner sample D (basis weight: 289.7 g / m 2 ). (5) Cord base paper A pulp slurry containing 100% recycled corrugated pulp by weight was mixed with 0.4% waterproofing material to prepare a paper stock. Next, a single layer of paper was made from this paper stock, dried in a dryer, and smoothed using a calender to produce corrugating base paper (basis weight: approximately 200 g / m 2 ).

[0061] Evaluation of liner and corrugating materials. The paper quality of the liner samples and medium base paper is shown in Table 1. (Basis Weight) Measured in accordance with JIS P 8124. (Average coating layer thickness, moisture permeability per unit coating layer thickness) The sample was cut into strips, and the thickness of the coating layer (waterproof layer) was measured at 10 random points on the cross section using an electron microscope. The average value was calculated as the average coating layer thickness. The moisture permeability per unit coating layer was also calculated by dividing the moisture permeability by the average coating layer thickness. (Oken Smoothness) Oken Smoothness was measured in accordance with JIS P 8155 using a digital Oken air permeability smoothness tester (Asahi Seiko). (Longitudinal elongation, transverse elongation) Measured in accordance with JIS P 8113. (Specific Compressive Strength) The compressive strength was measured in accordance with JIS P 8126, and the compressive strength was divided by the basis weight to calculate the specific compressive strength. (Burst Ratio) Burst strength was measured in accordance with JIS P 8131, and the burst ratio was calculated by dividing the burst strength by the basis weight. (Wet burst strength residual rate) Each sample was placed in water and left for 60 minutes (1 hour), and then the water was wiped off. The burst strength of the sample was measured in accordance with JIS P 8131, and the burst strength index was calculated by dividing this value by the basis weight. The value obtained by dividing this value by the burst strength index (the burst strength index of the sample before contact with water) was taken as the wet burst strength residual rate. (Cobb Water Absorbency) Measurement was carried out by the Cobb method in accordance with JIS P 8140. That is, 100 ml of distilled water was brought into contact with the surface (coated surface), and the weight of water absorbed per unit area after a specified time was measured. Note that the measurement time was the usual specified time of 120 seconds (2 minutes), and also 30 minutes. (Moisture permeability) Measured from the surface side (coated side) in accordance with JIS Z 0208. (Water repellency) The surface side (coated side) was measured in accordance with JAPAN TAPPI Paper and Pulp Test Method No. 68 "Paper and Paperboard - Water Repellency Test Method." (Contact Angle) One drop (50 μl) of distilled water was dropped onto the sample surface, and the contact angle was measured one second later using a contact angle measuring device (DAT1100 manufactured by FIBRO System AB). (Oil repellency) The surface side (coated side) was measured in accordance with JAPAN TAPPI Paper and Pulp Test Method No. 41 "Paper and paperboard - Oil repellency test method - Kit method." (Drop oil absorbency) Using a microsyringe equipped with an H5 needle, one drop of diesel No. 1, whose dynamic viscosity coefficient was adjusted to 3 cSt, was dropped onto the surface of the sample, and the time until the surface no longer became glossy was measured.

[0062] [Table 1]

[0063] Corrugated cardboard sheet manufacturing Corrugated cardboard sheets for box making were produced from each liner sample. Specifically, liner samples A to D were used for both the front and back liners, and the front and back liners were bonded together via medium base paper so that the surface layer side (the water-repellent layer or waterproof layer side) was on the outside of the cardboard sheet to produce the cardboard sheet. The cardboard sheet thickness was 5 mm (A flute).

[0064] Manufacturing and evaluation of snow leisure equipment (1) Snow sledding Each cardboard sheet was folded to create a cardboard snow sled with a base length of 75 cm, width of 45 cm, and height of 15 cm. The snow sleds were loaned to 10 first-grade elementary school children (average weight 21 kg), who were asked to freely slide down a snowy mountain (50 cm of snow) with an average temperature of 0°C and an average slope of 10 degrees (see Figure 1), and the damage to the cardboard sheets was evaluated after two hours. ○: The original shape is still intact after 2 hours and it can still be used ×: Broken within 2 hours and not suitable for continued use

[0065] (2) Cardboard tent A snow tent model (length 38.6 cm, depth 16.4 cm, height 18.2 cm) shown in Figure 2 was created and placed on a snow surface approximately 20 cm deep with the doors closed. After leaving it for 12 hours (overnight) in an environment with an average temperature of 0°C and an average snowfall of 2 cm per hour, it was confirmed whether it maintained its original shape. ○: The original shape is still intact after 12 hours and it can still be used ×: The strength of the model has decreased after 12 hours, making it difficult to use it any further.

[0066] (3) Cardboard table A cardboard table (width 29.7 cm, overall depth 23.6 cm, tabletop depth 21.0 cm, height 10.5 cm) shown in Figure 3 was made and left on a snow surface approximately 20 cm deep for 12 hours (overnight) in an environment with an average temperature of 0°C and an average snowfall of 2 cm per hour, after which it was confirmed whether it maintained its original shape. ○: The original shape is still intact after 12 hours and it can still be used ×: After 12 hours, the strength of the table has decreased and it is difficult to use it any further.

[0067] (2) Mixed recyclability Each cardboard sheet sample was cut into 25 mm square pieces, weighed out at a ratio of 40 g, diluted to 2% with 1.5 L of 45°C water, and then disintegrated for 30 minutes using a Tappi disintegrator. Next, wet sheets were formed and pressed according to JIS P 8222, and then dried on a plate heated to 50°C for 2 hours to produce hand-made sheets (basis weight: approximately 50 g / m). 2 ). Next, the surface appearance of the hand-made sheet was visually evaluated based on the following criteria. ○: There is no noticeable foreign matter on the paper surface, and there are no particular issues with regard to recycling. ×: Foreign matter is noticeable on the paper surface, which poses a problem in terms of recycling. The results are shown in Table 2.

[0068] [Table 2]

[0069] From the above results, it can be seen that the snow-resistant paper of the present invention can be recycled as waste paper after use and can be suitably used for winter leisure activities and the like.

Claims

1. Snow-resistant paper characterized in that a snow-resistant resin layer is coated on at least one side of a paper base material.

2. Coating amount of snow-resistant resin layer: 1 to 20 g / m ２ The snow-resistant paper according to claim 1,

3. The snow-resistant resin layer is made of at least one of styrene resin, acrylic resin, and polyolefin resin.

3. The snow-resistant paper according to claim 1, which contains one of the above and a wax.

4. 3. A method for producing the snow-resistant paper according to claim 1, comprising the step of coating a snow-resistant resin layer on at least one surface of a paper substrate.

5. A box comprising the snow-resistant paper according to claim 1 or 2.

6. A cardboard sheet comprising the snow-resistant paper according to claim 1 or 2.

7. A paper product made using the snow-resistant paper according to claim 1 or 2.

8. A paper product made using the cardboard sheet according to claim 6.

9. 9. The paper product according to claim 8, which is a paper playground equipment for making a snowy mountain.

10. The paper product according to claim 8, which is a paper building.

11. The paper product according to claim 8, which is paper furniture.

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