Coated and packaging paper

Abstract

To provide coated paper that prevents contents from sticking and has excellent suitability for bag making. The present invention provides a paper substrate and an anti-adhesion layer on at least one of the outermost surfaces thereof. The Shopper-Riegler freeness of the pulp constituting the paper base material is 50° SR or more and 90° SR or less, The ratio of softwood kraft pulp to the total pulp is 40% by weight or more, The coating amount (dry weight) of the anti-adhesion layer per side is 3 g / m 2 That's all, The anti-adhesion layer of the coated paper has a static friction coefficient of 0.3 or less and a water contact angle (10 seconds) of 85° or more.

Description

[Technical Field]

[0001] The present invention relates to coated paper that prevents contents from sticking and has excellent suitability for bag making, and to packaging paper that includes this coated paper. [Background technology]

[0002] In recent years, due to environmental considerations, the replacement of film with paper has been considered for packaging paper. While film has multiple barrier properties such as water resistance, oil resistance, water repellency, water vapor barrier, moisture permeability, and oxygen barrier properties, as well as excellent suitability for bag making, paper has not yet reached the same level of performance as film. Patent documents 1 and 2 describe a film having a heat seal layer on one side and a moisture permeability of 1,000 g / m 2 ·2,000g / m over 24hr 2 24hr or less or moisture permeability 300g / m 2 ·1,200g / m over 24hr 2 -Heat seal paper with a life of 24 hours or less is listed. Paper-based packaging materials used as a substitute for plastic film have been developed with the primary focus on improving barrier properties, and their suitability for packaging has not been fully explored. In addition, their moisture permeability has not been sufficient to be considered as a substitute for film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-024905 [Patent Document 2] Japanese Patent Application Publication No. 2023-107689 Summary of the Invention [Problem to be solved by the invention]

[0004] Convenience stores, supermarkets, etc. sell rice balls, nori rolls, and other cooked rice wrapped in film. When we considered replacing this film with paper, we found that the rice and nori would stick to the paper. The present invention is intended to solve this problem, and aims to provide coated paper that is less likely to have contents stick to it and has excellent suitability for bag making. [Means for solving the problem]

[0005] The means for solving the problems of the present invention are as follows. 1. A paper substrate and an anti-adhesion layer on at least one of the outermost surfaces, The Shopper-Riegler freeness of the pulp constituting the paper base material is 50° SR or more and 90° SR or less, The ratio of softwood kraft pulp to the total pulp is 40% by weight or more, The coating amount (dry weight) of the anti-adhesion layer per side is 3 g / m 2 That's all, Coated paper characterized in that the anti-adhesion layer has a static friction coefficient of 0.3 or less and a water contact angle (10 seconds) of 85° or more. 2. The basis weight of the paper base is 60 g / m 2 1. Coated paper according to 1., characterized in that: 3. Moisture permeability as coated paper is 150g / m 2 · 3. The coated paper according to 1. or 2., characterized in that the drying time is 1 day or less. 4. Coated paper according to any one of 1. to 3., characterized in that the tensile strength in the machine direction is 1.4 kN / m or more. 5. Coated paper according to any one of 1. to 4., characterized in that the bending resistance in the machine direction (Handle-O-Meter method) is 1500 mN / 100 mm or less. 6. A coated paper according to any one of 1. to 5., This wrapping paper is used for wrapping any of cooked rice, bread, Japanese sweets, Western sweets, and fried foods. [Effects of the Invention]

[0006] The coated paper of the present invention prevents contents from sticking to it. The coated paper of the present invention tears easily during bag-making processing, and is less likely to wrinkle or tear during pillow bag-making processing, making it highly suitable for bag making. The coated paper of the present invention has low moisture permeability, making it less susceptible to moisture penetration from the outside and drying out (e.g., loss of moisture from the inside), and therefore has excellent quality retention for contents. The coated paper of the present invention can be suitably used as packaging paper for foods such as rice balls, seaweed rolls, and sandwiches. DETAILED DESCRIPTION OF THE INVENTION

[0007] The coated paper of the present invention has a paper substrate and an anti-adhesion layer on at least one outermost surface, The Shopper-Riegler freeness of the pulp constituting the paper base material is 50°SR or more and 90°SR or less, The ratio of softwood kraft pulp to the total pulp is 40% by weight or more, The coating amount (dry weight) of the anti-adhesion layer per side is 3 g / m 2 That's all, The anti-adhesion layer has a static friction coefficient of 0.3 or less and a water contact angle (10 seconds) of 85° or more.

[0008] "Paper base material" (pulp) Pulp may be any of a variety of known pulps, including bleached softwood kraft pulp (NBKP), unbleached softwood kraft pulp (NUKP), bleached hardwood kraft pulp (LBKP), unbleached hardwood kraft pulp (LUKP), and sulfite pulp (SP) and other wood-based chemical pulps; ground pulp (GP), refiner ground pulp (RGP), stone ground pulp (SGP), chemi-ground pulp (CGP), semi-chemical pulp (SCP), thermomechanical pulp (TMP), and chemi-thermomechanical pulp (CTMP); non-wood pulp obtained from kenaf, bagasse, bamboo, hemp, straw, and the like; and recycled paper pulp obtained by removing ink from recycled paper in a deinking process. Among these, chemical pulps such as LBKP and NBKP, which are less likely to be contaminated with foreign matter, are preferred, and it is also preferred that the blending amount of recycled paper pulp is small. Specifically, the amount of chemical pulp relative to the total pulp is preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, and particularly preferably 100% by weight. The amount of recycled paper pulp relative to the total pulp is preferably 10% by weight or less, more preferably 5% by weight or less, even more preferably 1% by weight or less, and most preferably zero.

[0009] The paper base material of the present invention has a softwood kraft pulp (NBKP, NUKP) content of 40% by weight or more relative to the total pulp. Having a softwood kraft pulp content of 40% by weight or more relative to the pulp makes it easy to obtain sufficient tear strength and tensile strength during bag manufacturing. The softwood kraft pulp content relative to the total pulp can be 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, 100% by weight, etc.

[0010] (Other additives) Other additives may be added to the paper base material as needed, such as fillers, pigments, sizing agents, coagulants, fluorescent whitening agents, aluminum sulfate, retention aids, drainage aids, dry strength agents, wet strength agents, coloring dyes, coloring pigments, and waterproofing agents, which may be used alone or in combination.

[0011] (Freeness) The paper base material of the present invention has a Shopper-Riegler freeness of the pulp constituting the paper base material of 50°SR or more and 90°SR or less. The Shopper-Riegler freeness is a value indicating the degree of beating of the pulp, with a higher value indicating a more advanced beating. The pulp constituting the paper base material refers to all pulp contained in the paper base material. A paper base material with a Shopper-Riegler freeness of less than 50°SR has low strength, and therefore breakage of the paper base material and deterioration of the paper base material's formation are significant when a resin coating solution is applied, which can result in unevenness in various performances. Furthermore, a Shopper-Riegler freeness of more than 90°SR can cause uneven absorption of the resin coating solution into the paper base material when it is applied, resulting in unevenness in various performances. The Shopper-Riegler freeness is preferably 50°SR or more and 80°SR or less, and more preferably 50°SR or more and 75°SR or less. Furthermore, a freeness within the above range also provides excellent dimensional stability of the paper base material.

[0012] (Manufacturing method) The paper substrate can be produced using a method known in the art for papermaking, such as a Fourdrinier paper machine, a cylinder paper machine, a short wire paper machine, a twin-wire paper machine, an on-top hybrid paper machine, or a gap former machine.

[0013] (Calendar processing) Calendering is preferably performed to increase the density and smoothness of the paper substrate and prevent penetration of the coating liquid. The type of calender is not particularly limited, and ordinary smoothing treatment devices such as super calenders, gloss calenders, soft calenders, heat calenders, and shoe calenders can be used. The paper substrate of the present invention can be surface-treated using a calender such as a super calender or a high-temperature soft nip calender.

[0014] (basis weight of paper base material) The basis weight of the paper substrate is not particularly limited, but from the viewpoint of bag-making processability, it is preferably 60 g / m 2 The basis weight is preferably 60 g / m or less. 2 If the paper is thicker than this, the paper will be thicker and stiffer, which may cause wrinkles or tears during bag making and may make it harder to cut. There is no particular lower limit for the basis weight, but it is recommended that the paper be 20 g / m². 2 The lower the basis weight of the base material, the more likely it is that uneven adhesion of the coating liquid occurs, which is thought to be due to the influence of the pulp fiber formation, and this causes unevenness in various performances. The basis weight of the paper base material is 55 g / m 2 Less than 50 g / m is more preferable. 2 More preferably, 45 g / m 2 Even more preferably, it is 40 g / m or less, and even more preferably, it is 40 g / m or less 2 The following is the result.

[0015] (Paper base thickness) The thickness of the paper substrate is preferably 30 μm or more. If the thickness is thinner than 30 μm, the cutting properties tend to be poor. The upper limit of the thickness of the paper substrate can be about 50 μm.

[0016] (Air resistance of paper substrate) The paper substrate preferably has an Oken air resistance of 500 seconds or more so that the resin coating liquid remains on the surface of the paper substrate. The Oken air resistance of the paper substrate is more preferably 800 seconds or more, and even more preferably 1100 seconds or more. The upper limit of the Oken air resistance of the paper substrate is not particularly limited, but is, for example, about 10,000 seconds.

[0017] "Anti-adhesion layer" The anti-adhesion layer is a resin coating layer provided on at least one outermost surface of the paper substrate, and has a static friction coefficient of 0.3 or less and a water contact angle (10 seconds) of 85° or more. In this case, the anti-adhesion layer can be provided on the outermost surface of both paper substrates, but it is preferable to provide it on only one of them to prevent blocking. The coated paper of the present invention can also have other layers between the paper substrate and the anti-adhesion layer, such as a filling layer, adhesive layer, gas barrier layer, water vapor barrier layer, pigment coating layer, oil-resistant layer, or water-resistant layer.

[0018] In the present invention, the anti-adhesion layer has a static friction coefficient of 0.3 or less and a water contact angle (10 seconds) of 85° or more. The coated paper of the present invention has an anti-adhesion layer on its outermost surface that satisfies the static friction coefficient and water contact angle (10 seconds), thereby providing excellent adhesion prevention for contents. Therefore, the coated paper of the present invention can be used as packaging paper for sticky items. It is particularly suitable for packaging sticky foods such as cooked rice (e.g., rice balls, nori rolls, etc.); bread (e.g., sandwiches, sweet rolls, etc.); Japanese sweets (e.g., dango, daifuku, dorayaki, manju, kusamochi, mochi, yokan, monaka, castella, karinto, gyuhi, etc.); Western sweets (e.g., madeleines, financiers, donuts, canelés, caramel, chocolate, etc.); and fried foods (e.g., fried chicken, cutlets, croquettes, etc.). This is because the packaging can be peeled off without the food sticking to the packaging paper, making it easy to remove the food without losing its shape.

[0019] (coefficient of friction) The static friction coefficient of the anti-adhesion layer is preferably 0.25 or less, more preferably 0.2 or less, and even more preferably 0.15 or less. The coefficient of dynamic friction of the anti-adhesion layer is preferably 0.20 or less, more preferably 0.2 or less, and even more preferably 0.15 or less. If the coefficient of friction becomes too large, the sliding properties between the coated paper and the contents decrease, making the contents more likely to stick to each other.

[0020] (water contact angle) The water contact angle (10 seconds) of the antiadhesion layer is preferably 86° or more, more preferably 87° or more, even more preferably 88° or more, and even more preferably 89° or more. When the water contact angle is small, water easily penetrates into the coated paper, and the contents are more likely to adhere to the paper via the water.

[0021] (Tape peel strength) The anti-adhesion layer preferably has a peel strength (T-type) of 0.3 N / 18 mm or less, more preferably 0.2 N / 18 mm or less, and even more preferably 0.1 N / 18 mm or less, of the single-sided adhesive Scotch tape (manufactured by 3M, Scotch (registered trademark) Removable Tape 811).

[0022] (Resin contained in the anti-adhesion layer) The anti-adhesion layer is formed by coating a resin coating liquid. The resin contained in the anti-adhesion layer is not particularly limited as long as it can form an anti-adhesion layer that satisfies the static friction coefficient and water contact angle described above, but a resin with a water repellency of R5 or more measured by the following method is preferred. The water repellency of the resin is more preferably R6 or more, even more preferably R7 or more, even more preferably R8 or more, even more preferably R9 or more, and most preferably R10. ·Measurement method The undiluted coating solution was dropped onto an OHP film, and a YBA-type Baker applicator (Yoshimitsu Seiki Co., Ltd.) was used to create a coating layer of approximately 100 μm at the scale position 4, which was then dried in a dryer at 105°C for 2 hours to create a sheet. The water repellency of the resulting sheet was measured in accordance with the water repellency test method (JAPAN TAPPI No. 68:2000).

[0023] Resins with a water repellency of R5 or higher are not particularly limited, but acrylic resins are preferred from the viewpoint of preventing sticking. An acrylic resin refers to a resin with the highest molar ratio of acrylic monomers. For example, a ternary copolymer includes a copolymer of 40 mol % acrylic monomer, 30 mol % second monomer, and 30 mol % third monomer. Examples of acrylic monomers include acrylic acid, methacrylic acid, and (meth)acrylic acid esters. The acrylic resin may be a polymer consisting only of acrylic monomers, or a copolymer containing other monomers. Examples of copolymers include styrene-acrylic copolymers and ethylene-acrylic copolymers, with styrene-acrylic copolymers being preferred.

[0024] The resin coating solution for forming the anti-adhesion layer may contain, in addition to a resin having a water repellency of R5 or more, additives such as a resin having a water repellency of less than R5, a surfactant, an antifoaming agent, a surface sizing agent, a paper strength agent, a water retention agent, a thickener, a release agent, and an anti-slip agent, provided that the resin coating solution does not impair its performance. However, when a resin having a water repellency of less than R5 is contained, the proportion of the resin having a water repellency of R5 or more relative to the total resin is preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, and even more preferably 95% by weight or more.

[0025] (Coating method) The coating method for the anti-adhesion layer is not particularly limited, and any known coating method can be used. Specifically, a surface coating method using a blade coater, bar coater, champlex coater, gravure coater, die coater, curtain coater, air knife coater, spray coater, etc. can be appropriately selected and used. Among these, the blade coater, bar coater, and air knife coater are preferred because they are likely to form a uniform coating layer. The resin coating liquid may be either a water-based liquid using a solvent such as water or a solvent-based liquid using a solvent such as an organic solvent, but is preferably a water-based liquid from the viewpoint of safety and hygiene.

[0026] (coating amount) The coating amount (dry weight) of the anti-adhesion layer per side is 3.0 g / m 2 This coating amount is 5.0 g / m 2 More preferably, 8.0 g / m or more 2 The upper limit of the coating amount is not particularly limited, but for example, 15 g / m 2 The coating weight is preferably 15 g / m or less. 2 Beyond this, there is little improvement in performance and it is expensive. The anti-adhesion layer may be a multi-layer. When the anti-adhesion layer is a multi-layer, the total coating amount (dry weight) per side may be within the above range, but in consideration of productivity, processability, etc., a single coating layer is preferred.

[0027] "Performance of coated paper" (moisture permeability) The coated paper of the present invention has a moisture permeability of 150 g / m 2 It is preferable that the moisture permeability is 150 g / m 2 By keeping the storage life at 10 days or less, it is possible to prevent moisture from entering from the outside and moisture from escaping from the inside, thereby suppressing changes in the moisture content of the contents. The moisture permeability of coated paper is 120 g / m 2 ·Day or less is preferable, 90g / m 2 ·day or less is more preferable, 60g / m 2 30g / m 2 The lower limit of the moisture permeability of the coated paper is not particularly limited, but for example, 10 g / m 2 ·day, 20g / m 2 ·day etc.

[0028] (tensile strength) The coated paper of the present invention preferably has a tensile strength in the machine direction (MD) of 1.4 kN / m or more. Coated paper with a tensile strength in the machine direction of 1.4 kN / m or more is less likely to break during bag-making processing in a packaging machine, and has excellent bag-making suitability. The tensile strength in the machine direction (MD) is more preferably 1.8 kN / m or more, even more preferably 2.2 kN / m or more, and even more preferably 2.5 kN / m or more. The tensile strength is a value measured in accordance with JIS P8113:2006.

[0029] (Tear strength) The coated paper of the present invention desirably has a tear strength in the cross direction (CD) of 100 mN or more. When bags are made in a packaging machine, a load is applied in the cross direction when the contents are wrapped in the former, making it prone to tearing in the cross direction. If the tear strength in the cross direction is 100 mN or more, the paper is less likely to break or tear during bag making in the packaging machine, and is therefore excellent in suitability for bag making.

[0030] (Bending resistance of paper base material) The coated paper of the present invention preferably has a bending resistance (Handle-O-Meter method) in the machine direction (MD) of 1500 mN / 100 mm or less. Coated paper with a bending resistance of 1500 mN / 100 mm or less is flexible and therefore easily deforms to conform to the shape of the contents, making it less likely to damage the contents during bag-making processes. The bending resistance (Handle-O-Meter method) in the machine direction (MD) is more preferably 1200 mN / 100 mm or less, even more preferably 1000 mN / 100 mm or less, and even more preferably 900 mN / 100 mm or less. The bending resistance is a value measured in accordance with the Handle-O-Meter method of JIS L1913:2010.

[0031] (Heat seal strength) In the coated paper of the present invention, the outermost anti-adhesion layer preferably has heat-sealing properties. When the anti-adhesion layer has heat-sealing properties, it is preferable that the substrate is destroyed when the anti-adhesion layers are thermally bonded together and peeled off. The coated paper of the present invention preferably has a 120°C MD heat seal strength of 0.5 N / 15 mm or more, more preferably 1.0 N / 15 mm or more, even more preferably 1.5 N / 15 mm or more, even more preferably 2.0 N / 15 mm or more, even more preferably 2.5 N / 15 mm or more, and even more preferably 3.0 N / 15 mm or more; and a 120°C CD heat seal strength of 0.5 N / 15 mm or more, more preferably 1.0 N / 15 mm or more, even more preferably 1.5 N / 15 mm or more, even more preferably 2.0 N / 15 mm or more, and even more preferably 2.5 N / 15 mm or more.

[0032] The coated paper of the present invention preferably has a 160°C MD heat seal strength of 1.0 N / 15 mm or more, more preferably 1.5 N / 15 mm or more, even more preferably 2.0 N / 15 mm or more, even more preferably 2.5 N / 15 mm or more, and even more preferably 3.0 N / 15 mm or more; and a 160°C CD heat seal strength of 0.5 N / 15 mm or more, more preferably 1.0 N / 15 mm or more, even more preferably 1.5 N / 15 mm or more, even more preferably 2.0 N / 15 mm or more, and even more preferably 2.5 N / 15 mm or more. [Example]

[0033] (Evaluation method) Freeness (Schopper Riegler) Pulp was measured in accordance with JIS P8121-1:2012. ·Basic weight The paper substrate and coated paper were measured in accordance with JIS P8124:2011. ·Paper thickness The paper substrate and coated paper were measured in accordance with JIS P8118:1998. ·density For paper substrates and coated papers, the values ​​were calculated from the measured values ​​of basis weight and thickness.

[0034] ·Smoothness (Oken style) The coated and uncoated surfaces of the paper substrate and coated paper were measured using a water column type Oken type air permeability and smoothness tester (manufactured by Asahi Seiko Co., Ltd.) in accordance with JIS P8155:2010. ·Air permeability resistance (Ouken style) For the paper substrate and coated paper, the average of four measurements was calculated according to the Oken tester method described in JIS P8117 (2009) for air permeability and air resistance, and this was taken as the air resistance (Oken method) (seconds). The measurement range for air resistance using the water column type Oken air permeability / smoothness tester (KY5 model, manufactured by Asahi Seiko Co., Ltd.) is 0 to 5,000 seconds.

[0035] Tensile strength The paper substrate and coated paper were measured in accordance with JIS P8113:2006. Tear strength The coated paper was measured in accordance with JIS P8116:2022. ·Moisture permeability For coated paper, measurements were made under condition B (temperature 40±0.5°C, relative humidity 90%±2%) in accordance with JIS Z0208:1976 "Test method for moisture permeability of moisture-proof packaging materials (cup method)". The weight after leaving it in the environmental tester for 16 hours was taken as the initial value, and the weight was measured again after leaving it for 2 hours. The change in weight was converted into the moisture permeability over 24 hours.

[0036] Water repellency The coated surface (surface of the anti-adhesion layer) was measured in accordance with JAPAN TAPPI Paper and Pulp Test Method No. 68 "Paper and Paperboard - Water Repellency Test Method." ·Water contact angle 4.0 μl of pure water was dropped onto the coated surface (surface of the anti-adhesion layer), and the dynamic contact angle 10 seconds after the dropping was measured using a contact angle measuring device (DAT1100, manufactured by FIBRO System). -Static friction coefficient, kinetic friction coefficient The static and dynamic friction coefficients in the MD direction of the coated surfaces (anti-adhesion layer surfaces) were measured by the horizontal method in accordance with JIS P8147.

[0037] Heat seal strength The test was carried out in accordance with JIS Z1707:2019 7.4 "Heat seal strength test". Two square test pieces, each 100 mm on a side, were cut out from the obtained coated paper, and the anti-adhesion layers were brought into contact with each other and heat-sealed using a heat seal tester (TP-7018, manufactured by Tester Sangyo Co., Ltd., seal width 10 mm) at pressure temperatures of 120°C and 160°C, respectively, with a pressure of 98 kPa and a pressure time of 1.0 second.Furthermore, a measurement sample with a long side of 100 mm and a short side of 15 mm was cut out from the heat-sealed 100 mm square test piece. The measurement sample was left at 23°C and 50% RH for 10 minutes, and in this atmosphere, the long edge was clamped between the upper and lower jigs of a Tensilon universal testing machine (A&D Co., Ltd., RTG-1210). The measurement sample was peeled (T-type) from the long edge at a speed of 300 mm / min to measure the peel strength, i.e., HS strength (N / 15 mm). The heat seal strength was measured under two conditions: when the long side was in the MD (machine direction of the paper) and when the long side was in the CD (cross direction of the paper).

[0038] Cutting performance evaluation A test piece 50 mm wide (CD direction) was prepared. This test piece was held at the top end and hung with a 300 g weight attached to the bottom end, and a cutting test was performed with n=10 by pressing the cutter blade (mountain-shaped blade, cutter type) of a packaging machine horizontally against it, and the cutting test was evaluated according to the following criteria. (Evaluation criteria) 〇: I was able to cut everything. △: 1-2 pieces cannot be cut. ×: Cannot be cut. 3 or more pieces.

[0039] Evaluation of rice adhesion Two pieces of coated paper cut to 50 x 50 mm were prepared, and 10 g of freshly cooked rice was placed in the center of the uncoated side of one piece, then the rice was spread so that it covered the entire surface of the paper, and sandwiched between the other piece of coated paper (the surface with the anti-adhesion layer). Two glass slides (approximately 12.5 g) were placed on top without overlapping. After one hour, the coated paper on top was peeled off, and the adhesion of the rice to the anti-adhesion layer was checked and evaluated according to the following criteria. (Evaluation criteria) O: Not a single grain of rice is stuck together. ×: One or more grains of rice are stuck together.

[0040] Evaluation using a horizontal pillow bag making machine A test was conducted using a horizontal pillow packaging machine (SP-803N manufactured by Suzuki Seisakusho Co., Ltd.) to package plastic plates (65mm x 55mm). Using a roll of coated paper 150mm wide, the vertical sealing temperature was 160°C, the horizontal sealing temperature was 135°C, and 30 plates were packaged consecutively so that the finished pillows were 60mm wide and 105mm long. The results were evaluated according to the following criteria. (Evaluation criteria) Good: No tears, no peeling stickers. △: No tears, sticker peeled off. ×: There is a tear.

[0041] Tape peel strength A single-sided adhesive tape (3M, Scotch (registered trademark) Removable Tape 811) was applied to the coated surface of the coated paper parallel to the MD direction, and a 250 g weight (70 × 19 × 24 mm, SUS) was slid across it at a speed of approximately 30 seconds / 8 cm to press it in place. A sample was cut to the width of the tape, and the edge was peeled off to form the clamping portion. The peel strength, i.e., tape peel strength (N / 18 mm), was measured by clamping the peeled portion between the upper and lower jigs of a Tensilon universal testing machine (A&D Co., Ltd., RTG-1210) and peeling the measurement sample (T-type) at a speed of 300 mm / min.

[0042] As paper substrates for coating, the paper substrates shown in Examples 1 to 4 and the paper substrate shown in Comparative Example 1 were prepared, and the paper quality and cuttability in a bag making machine were evaluated. <Preparation of paper base materials 1 to 5> Example 1 Softwood kraft pulp (NBKP) and hardwood kraft pulp (LBKP) were mixed at a ratio of 65% by weight / 35% by weight and beaten to a freeness of 74°SR according to the Schopper-Riegler method to prepare paper stock. Paper was made on a long rope paper machine, dried in a dryer, and calendered to a density of 30.1 g / m2 A paper substrate 1 of the above was obtained.

[0043] Example 2 100% softwood kraft pulp (NBKP) was beaten to a freeness of 89°SR by the Schopper-Riegler method to prepare paper. The paper was made on a long rope paper machine and dried in a dryer to a density of 19.4 g / m. 2 A paper substrate 2 was obtained. Example 3 Softwood kraft pulp (NBKP) and hardwood kraft pulp (LBKP) were mixed at a ratio of 50% by weight / 50% by weight, and beaten to a freeness of 85°SR according to the Schopper-Riegler method to prepare paper. Paper was made on a long rope paper machine, dried in a dryer, and then dried to a weight of 21 g / m. 2 A paper substrate 3 was obtained. Example 4 100% softwood kraft pulp (NBKP) was beaten to a freeness of 60°SR by the Schopper-Riegler method to prepare paper. 7.0% by weight (based on the as-is pulp) of a wet strength agent was added, and the paper was made on a long-wire paper machine. After drying in a dryer, the paper was calendered to a density of 33.7 g / m. 2 A paper substrate 4 of the above was obtained.

[0044] (Comparative Example 1) 100% softwood kraft pulp (NBKP) was beaten to a freeness of 17°SR by the Schopper-Riegler method to prepare paper. The paper was made on a long-wire paper machine, dried in a dryer, and then calendered to a density of 37.4 g / m. 2 A paper base material 5 was obtained.

[0045] Table 1 shows the paper qualities of the paper base materials 1 to 5 and their cuttability during bag making. [Table 1]

[0046] ·result Paper substrates with pulp having a Shopper-Riegler freeness of 50°SR or more and 90°SR or less had excellent cuttability.

[0047] Next, the paper substrates 1 to 4 obtained in Examples 1 to 4, which had been evaluated as having good cuttability, were manually coated with a coating liquid containing a styrene-acrylic resin (Brightone FC641V, manufactured by Sakata Inx Corporation) with a water repellency of R10 using a Mayer bar, as in Examples 5 to 8 described below, to obtain coated paper samples 1 to 4, respectively. Similarly, the paper substrates 1 to 4 obtained in Examples 1 to 4 were manually coated with a coating liquid containing a polyolefin resin (Zaixen AC, manufactured by Sumitomo Seika Chemicals) with a water repellency of R6 using a Mayer bar, as described in Comparative Examples 2 to 5 below, to obtain coated paper samples 5 to 8, respectively. Tables 2 and 3 show the paper qualities and evaluations of coated paper samples 1 to 4 and 5 to 8, respectively.

[0048] [Table 2]

[0049] [Table 3]

[0050] ·result The coated papers obtained in Examples 5 to 8 had anti-adhesion layers with static friction coefficients of 0.3 or less and water contact angles (10 seconds) of 85° or more, and were able to prevent rice from adhering. In contrast, the coated papers obtained in Comparative Examples 2 to 5 had anti-adhesion layers with static friction coefficients of 0.41 to 0.64 and water contact angles (10 seconds) of 69.3 to 72.4°, and rice adhered to them.

[0051] Examples 9 to 10 The paper substrate and resin of Example 8 were bar coated on one side using an actual machine to obtain different coating amounts (dry weight), thereby obtaining coated paper samples 9-10. The paper quality is shown in Table 4. The obtained coated paper samples were subjected to a horizontal pillow packaging test (SP-803N, manufactured by Suzuki Seisakusho Co., Ltd.). The evaluation is shown in Table 4.

[0052] [Table 4]

[0053] ·result It was confirmed that the coated papers obtained in Examples 9 and 10 of the present invention have excellent bag-making processability and can be used for industrial packaging of foods and the like.

Claims

1. A paper substrate and an anti-adhesion layer on at least one outermost surface thereof, The Shopper-Riegler freeness of the pulp constituting the paper base material is 50°SR or more and 90°SR or less, The ratio of softwood kraft pulp to the total pulp is 40% by weight or more, The paper substrate has a basis weight of 60 g / m 2 or less, The thickness of the paper base material is 30 μm or more, The density of the paper base material is 0.54 g / cm 3 or more and 0.95 g / cm 3 or less, The coating amount (dry weight) of the anti-adhesion layer per side is 3 g / m ２ That's all, the anti-adhesion layer has a peel strength (T-type) of 0.3 N / 18 mm or less with a single-sided adhesive tape, Scotch tape (manufactured by 3M, Scotch (registered trademark) Removable Tape 811); the anti-adhesion layer has a static friction coefficient of 0.3 or less and a water contact angle (10 seconds) of 85° or more; The tensile strength in the longitudinal direction is 1.4 kN / m or more, A coated paper characterized by a tear strength in the transverse direction of 100 mN or more.

2. Moisture permeability as coated paper is 150 g / m ２ 2. The coated paper according to claim 1, characterized in that the aging time is 100 minutes or less.

3. 2. Coated paper according to claim 1, characterized in that the bending resistance in the machine direction (Handle-O-Meter method) is 1500 mN / 100 mm or less.

4. A coated paper according to any one of claims 1 to 3, This wrapping paper is used for wrapping any of cooked rice, bread, Japanese sweets, Western sweets, and fried foods.

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