Release paper base, release paper, and adhesive tape

Abstract

To provide a release paper base paper, and a release paper, which have a low basis weight, are easy to handle and have good processability when made into an adhesive tape, and an adhesive tape.SOLUTION: There are provided: a release paper base paper that comprises a paper base material 11 and a sealing layer 12 laminated on at least a portion of a surface of the paper base material 11, wherein the paper base material 11 has a basis weight of less than 20 g / m2, a paper thickness of less than 35 μm, and a tensile strength measured in accordance with JIS P8113:2006 in a longitudinal direction is 2.0 kN / m or more; a release paper that comprises the release paper base paper and a release agent layer laminated on at least a portion of a surface of the release paper base paper; and an adhesive tape that comprises a tape base material, an adhesive layer laminated on at least a portion of a surface of the tape base material, and the release paper according to claim 6, which is laminated on a surface of the adhesive layer opposite to the tape base material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to release paper base paper, release paper, and adhesive tape. [Background technology]

[0002] Release paper is a component that protects the adhesive layer of adhesive tape and prevents a decrease in adhesiveness. In recent years, from the perspective of reducing environmental impact, there has been a demand for reducing plastic waste and for recyclability. In particular, there is a growing demand for release paper that does not use a polyolefin layer, which is formed as a sealing layer to suppress the penetration of the release agent into the paper substrate and maximize its release properties (see, for example, Patent Document 1). Furthermore, from the perspective of reducing waste and improving transportation costs, there is a desire for lower basis weight of release paper. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-201990 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, simply lowering the basis weight of the release liner reduces its tensile strength, leading to a decrease in processing suitability, such as the release liner tearing during the peeling process when used in adhesive tape. For this reason, excessive reduction of the basis weight of the release liner has tended to be avoided.

[0005] Therefore, the main objective of this disclosure is to provide a release paper base, release paper, and adhesive tape that have a low basis weight, good handling properties, and good processability when used as an adhesive tape. [Means for solving the problem]

[0006] (1) A paper substrate and a sealing layer laminated on at least a portion of the surface of the paper substrate, wherein the paper substrate is 20 g / m²2 It is a release paper base paper having a basis weight of less than a certain amount and a paper thickness of less than 35 μm, and having a longitudinal tensile strength of 2.0 kN / m or more measured in accordance with JIS P 8113:2006. (2) The paper base material includes softwood pulp and hardwood pulp, and is the release paper base paper according to (1), wherein the weight mixing ratio of the softwood pulp and the hardwood pulp is 50:50 to 100:0. (3) The paper base material includes wood pulp and plastic fibers, and is the release paper base paper according to (1), wherein the content of the wood pulp is 50% by mass or more and 100% by mass or less based on the total mass of the paper base material, and the weight mixing ratio of the plastic fibers and the wood pulp is 10:90 to 49:51. (4) The paper base material is the release paper base paper according to (1), which contains a wet paper strength enhancer at 0.5% by mass or more and 20% by mass or less based on the total mass of the raw material pulp. (5) The paper base material is a treatment liquid containing a resin, which is applied or impregnated using a size press at 1.0 g / m or more and 5.0 g / m or less (in terms of dry solid content) per side, and is the release paper base paper according to any one of (1) to (4). 2 or more 2 and the following (in terms of dry solid content) and is the release paper base paper according to any one of (1) to (4). (6) A release paper including the release paper base paper according to (1) and a release agent layer laminated on at least a part of the surface of the release paper base paper. (7) A tape base material, an adhesive layer laminated on at least a part of the surface of the tape base material, and the release paper according to (6) laminated on the surface of the adhesive layer on the side opposite to the tape base material, and is an adhesive tape.

Advantages of the Invention

[0007] According to the present disclosure, it is possible to provide a release paper base paper, a release paper, and an adhesive tape that have a low basis weight, good handling properties, and good processing suitability when used as an adhesive tape.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of the release paper base paper according to the present embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view of the release paper according to this embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view of the adhesive tape according to this embodiment. [Modes for carrying out the invention]

[0009] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). This embodiment is illustrative for explaining the present invention and is not intended to limit the present invention to the following content. The present invention can be implemented by modifying it as appropriate within the scope of its gist.

[0010] Furthermore, identical elements in the drawings will be given the same reference numeral, and redundant explanations will be omitted. Unless otherwise specified, positional relationships such as top, bottom, left, and right will be based on those shown in the drawings. Moreover, the dimensional ratios in the drawings are not limited to those shown.

[0011] <Release paper base> Figure 1 is a schematic cross-sectional view of the release paper base according to this embodiment.

[0012] The release paper base 10 according to this embodiment includes a paper substrate 11 and a sealing layer 12 laminated on at least a portion of the surface of the paper substrate 11. The paper substrate 11 has a density of 20 g / m². 2 It has a basis weight of less than 35 μm and a paper thickness of less than 35 μm, and a longitudinal tensile strength of 2.0 kN / m or more as measured in accordance with JIS P 8113:2006. With this configuration, it is possible to produce a release paper base 10 that has a low basis weight, good handling properties, and good processability when used as an adhesive tape.

[0013] (Basis weight of paper substrate) The basis weight of the paper substrate 11 is 20 g / m². 2 It is less than 5 g / m². Furthermore, the lower limit of the basis weight of the paper substrate 11 is 5 g / m², from the standpoint of processability. 2 The above is preferable, 10 g / m 2 The above is preferable.

[0014] (Paper thickness of paper base material) The paper thickness of the paper substrate 11 is measured in accordance with the "Paper and paperboard - Test methods for thickness and density" described in JIS P8118 (2014). The lower limit of the paper substrate 11 thickness is preferably 10 μm, and more preferably 15 μm. The upper limit of the paper substrate 11 thickness is 35 μm or less, but more preferably 25 μm, and more preferably 20 μm. When the paper thickness of the paper substrate 11 is within the above range, the density of the paper substrate 11 is increased, which effectively suppresses the penetration of the release agent into the release paper base paper 10, enabling a lower basis weight and lighter weight of the release agent while maintaining strength. As a result, the workability and processability when manufacturing release paper using the release paper base paper 10, and the processability when peeling release paper from adhesive tape can be improved. When manufacturing paper thickness within the above range, it is desirable to perform calendering.

[0015] Calendering is a process that equalizes the smoothness and thickness of paper by passing it between rolls. Calendering increases the density of the paper substrate 11. Examples of calendering equipment include machine calenders, soft nip calenders, supercalenders, multi-stage calenders, and multi-nip calenders.

[0016] (Tensile strength in the longitudinal direction of paper substrate) The tensile strength of the paper substrate 11 in the longitudinal (MD) direction shall be measured in accordance with JIS P 8113:2006 (Paper and cardboard - Test methods for tensile properties). The test specimen shall be cut to approximately 25 mm (±0.5 mm) in the transverse direction and 150 mm in the longitudinal direction. The distance between the grips of the tensile testing machine shall be 100 mm, and the specimen shall be pulled in the longitudinal direction at a tensile speed of 300 mm / min. The tensile speed shall be 300 mm / min. Five sets of samples shall be prepared, and each shall be measured five times. The average of these measured values ​​shall be taken as the tensile strength in the longitudinal direction. The tensile strength of the paper substrate 11 in the longitudinal direction shall be 2.0 kN / m or more. Preferably, it shall be 5 kN / m or less, and more preferably 4 kN / m or less.

[0017] As the pulp constituting the paper base material 11, for example, wood pulps such as softwood kraft pulp (NBKP), hardwood kraft pulp (LBKP), softwood sulfite pulp (NBSP), and hardwood sulfite pulp (LBSP) can be used. The softwood pulp and hardwood pulp are not particularly limited, and for example, virgin pulp, waste paper pulp, etc. can be used. As the virgin pulp, it is preferable to use wood pulp. For example, chemical pulps such as softwood kraft pulp (NBKP), unbleached softwood kraft pulp (NUKP), semi-bleached softwood kraft pulp (NSBKP), softwood sulfite pulp, hardwood kraft pulp (LBKP), unbleached hardwood kraft pulp (LUKP), semi-bleached hardwood kraft pulp (LSBKP), hardwood sulfite pulp, etc., and mechanical pulps such as stone ground pulp (SGP), pressure stone ground pulp (TGP), chemiground pulp (CGP), groundwood pulp (GP), thermomechanical pulp (TMP), etc. can be mentioned. In addition, other non-wood pulps such as cotton pulp, hemp, bagasse, kenaf, esparto, paper mulberry, trifoliate orange, and kozo can be appropriately used.

[0018] Basis weight 20 g / m 2 In order to obtain the paper base material 11 with a basis weight of less than 20 g / m² and a longitudinal tensile strength of 2.0 kN / m or more, it is preferable that the paper base material 11 contains softwood pulp and hardwood pulp, and the weight mixing ratio of the softwood pulp and the hardwood pulp is a weight ratio (solid content weight) of 50:50 to 100:0, more preferably a weight ratio (solid content weight) of 80:20 to 99:1, and even more preferably a weight ratio (solid content weight) of 90:1 to 99:1.

[0019] Also, in the paper base material 11, it is preferable that the wood pulp is the main component. Specifically, the content ratio of the wood pulp in the paper base material 11 is preferably 50% by mass or more and 100% by mass or less. From the viewpoint of increasing the tensile strength of the paper base material 11, it is also preferable that it is a mixed paper containing plastic fibers in the paper base material 11. In this case, basis weight 20 g / m 2To obtain a paper substrate 11 with a strength of less than 2.0 kN / m and a longitudinal tensile strength of 2.0 kN / m or more, the wood pulp content is preferably 50% by mass or more and 100% by mass or less, and the weight ratio of plastic fibers to wood pulp is preferably 10:90 to 49:51, and more preferably 35:65 to 45:55.

[0020] The plastic fibers are preferably selected from the group including, for example, esters, polyethylene terephthalate (PET), polyamide (PA), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyether ether ketone (PEEK), polyisobutylene (PIB), polybutylene (PB), mixtures thereof, and copolymers thereof.

[0021] Also, basis weight 20g / m² 2 To obtain a paper substrate 11 with a tensile strength of less than 2.0 kN / m and a longitudinal tensile strength of 2.0 kN / m or more, it is preferable to include a wet paper strength enhancer in an amount of 0.5% to 20% by mass, and more preferably 5% to 15% by mass, relative to the total mass of the raw pulp. Examples of wet paper strength enhancers include polyamide-polyamine epichlorohydrin resin, urea-formaldehyde resin, epoxidized polyamide resin, melamine-formaldehyde resin, urea-formaldehyde resin, etc.

[0022] Furthermore, the basis weight is 20g / m². 2 To obtain a paper substrate 11 with a density of less than 2.0 kN / m and a longitudinal tensile strength of 2.0 kN / m or more, a resin-containing treatment solution is applied to one side at a rate of 1.0 g / m² using a size press. 2 More than 5.0g / m 2 It is preferable that the coating or impregnation is performed at the following rate (based on dry solids content): 1.5 g / m² per side. 2 More than 2.5g / m 2The following coating or impregnation methods are more preferable. As resin materials, for example, various polyvinyl alcohols, cellulose derivatives such as hydroxyethylcellulose and carboxymethylcellulose, water-soluble binders such as polyacrylamide, polyethylene oxide, polypropylene oxide, starch, modified starch, polyacrylic acid, sodium polyacrylate, and casein, polyethylene, polypropylene, polyisobutylene, polystyrene, polyacrylamide, ethyl polyacrylate, polymethyl methacrylate, polyacrylonitrile, polybutadiene, polyisoprene, polyethylene terephthalate, melamine resin, epoxy resin, alkyd resin, unsaturated polyester resin, emulsion-type binders such as styrene-butadiene copolymer, modified styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, methyl methacrylate-butadiene copolymer, and acrylic acid ester-methacrylic acid ester copolymer, or emulsion-type urethane resin binders can be used.

[0023] The paper substrate 11 may contain cellulose nanofibers. By including cellulose nanofibers in the paper substrate 11, it is possible to improve the glossiness of the paper substrate 11 and improve the yield in the papermaking process.

[0024] Cellulose nanofibers are single microfibrils of cellulose obtained by defibrating cellulosic raw materials, and have an average fiber diameter of less than 500 nm. The specific method for incorporating cellulose nanofibers can be either internal or external addition.

[0025] In addition to pulp and the aforementioned wet strength enhancers, the paper substrate 11 may contain various auxiliary agents as needed, such as fillers, sizing agents, bulking agents, yield enhancers, water drainage enhancers, aluminum sulfate, coloring dyes, coloring pigments, fluorescent whitening agents, fluorescent decolorizing agents, pH adjusters, defoamers, pitch control agents, and slime control agents. These may be used individually or in combination of two or more.

[0026] The density of the paper substrate 11 is 0.5 g / cm³. 3 More than 2.0g / cm 3 The following is preferable: 0.6 g / cm³ 3 More than 1.5g / cm 3 The following is more preferable: 0.7 g / cm³ 3 More than 1.3g / cm 3 The following is even more preferable: Density of 0.5 g / cm³ 3 If the density is less than 2.0 g / cm³, the release agent will penetrate too deeply, resulting in poor release properties. Furthermore, there is a risk of the release agent seeping through to the opposite side. On the other hand, a density of 2.0 g / cm³ is also important. 3 If it exceeds this point, the smoothness becomes too high, and applying a release agent will make the paper slippery.

[0027] The manufacturing method of the paper substrate 11, the papermaking method, and the type of paper machine are not particularly limited. For example, known manufacturing (papermaking) methods and paper machines such as long-wire paper machines, cylinder paper machines, short-wire paper machines, gap formers, hybrid formers (on-top formers), and twin-wire paper machines can be selected. Furthermore, the pH during papermaking is not particularly limited and may be in the acidic range (acidic papermaking), pseudo-neutral range (pseudo-neutral papermaking), neutral range (neutral papermaking), or alkaline range (alkaline papermaking). After papermaking in the acidic range, an alkaline agent may be applied to the surface of the paper layer. In addition, the paper substrate 11 may consist of one layer or be composed of two or more layers.

[0028] (Sealing layer) The sealing layer 12 effectively suppresses the penetration of the release agent into the paper substrate 11 and ensures a smooth surface for the release agent layer. Furthermore, from the viewpoint of reducing environmental impact, it is preferable that the sealing layer 12 does not contain polyolefins. If the sealing layer 12 is a polyolefin-free sealing layer, it can fully meet the aforementioned requirements for "plastic-free" and recyclability.

[0029] The sealing layer 12 preferably contains a binder resin. The binder resin is not particularly limited and can be any resin suitable for use in the coated paper field, etc. Examples of binder resins include polyvinyl alcohol-based resins such as fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, ethylene copolymerized polyvinyl alcohol, acetoacetylated polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol, nitrile-modified polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol, silicone-modified polyvinyl alcohol, and other modified polyvinyl alcohols; methyl methacrylate-butadiene copolymer, (meth)acrylic acid, and monomer components copolymerizable with (meth)acrylic acid (excluding olefins). Examples include acrylic resins; cellulose derivatives such as hydroxyethylcellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, and acetylcellulose; starches such as oxidized starch, etherified starch, and esterified starch; styrene resins such as styrene-maleic anhydride copolymer, styrene-butadiene copolymer, and styrene-acrylic copolymer; casein, gum arabic, polyvinyl chloride, polyvinyl acetate, polyacrylamide, polyacrylic acid ester, polyvinyl butyral, polystyrene and their copolymers, polyamide resins, silicone resins, petroleum resins, terpene resins, ketone resins, coumarone resins, dextrin, ethylene-vinyl chloride copolymer, and ethylene-vinyl acetate copolymer. Among these, it is preferable that there be at least one selected from the group consisting of polyvinyl alcohol resins, starches, and styrene resins. More preferably, there is at least one selected from the group consisting of polyvinyl alcohol (fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol), oxidized starch, and styrene copolymers (styrene-maleic anhydride copolymer, styrene-butadiene copolymer, styrene-acrylic copolymer, etc.). These may be used individually or in combination of two or more types.

[0030] The sealing layer 12 preferably contains an inorganic pigment, and more preferably contains the binder resin and the inorganic pigment described above. Examples of inorganic pigments include light calcium carbonate, heavy calcium carbonate, kaolin, calcined kaolin, engineered kaolin, clay, delaminated clay, talc, silica, colloidal silica, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, calcium silicate, magnesium silicate, aluminum hydroxide, alumina, magnesium carbonate, magnesium hydroxide, kaolinite, antigorite, smectite, vermiculite, mica, etc. Among these, it is preferable that one is selected from the group consisting of kaolin, calcined kaolin, and engineered kaolin, and kaolin is more preferable. These may be used individually or in combination of two or more.

[0031] The inorganic pigment content is not particularly limited, but from the viewpoint of smoothness and binding properties, it is preferably 1 to 1400 parts by mass, more preferably 200 to 600 parts by mass, even more preferably 250 to 500 parts by mass, and even more preferably 300 to 400 parts by mass per 125 parts by mass of binder resin by dry weight.

[0032] The sealing layer 12 may contain various commonly used auxiliary agents as needed, such as sizing agents, water-resistant agents, water-repellent agents, dyes, surfactants, dispersants, thickeners, water-retaining agents, defoaming agents, water-resistant agents, dyes, fluorescent dyes, and crosslinking agents.

[0033] The amount of sealing layer 12 applied is 0.2 g / m² by dry weight. 2 More than 20g / m 2 The following is preferable. The application amount is 0.5 g / m². 2 It is more preferable that the value be greater than or equal to 0.7 g / m 2 It is even more preferable that the amount is greater than or equal to 10 g / m². Furthermore, the upper limit of this application amount is 10 g / m². 2 More preferably, the following is true: 8 g / m 2It is even more preferable that the following conditions are met: By setting the amount of sealing layer 12 applied to be above the lower limit, the penetration of the release agent into the paper substrate 11 can be suppressed more effectively, and the smoothness of the surface of the release agent layer can be further improved. On the other hand, by setting the amount of sealing layer 12 applied to be below the upper limit, the drying load during coating can be further reduced, which is more preferable in terms of operation and cost. When the sealing layer 12 consists of two or more layers, it is preferable that the application amount of at least one layer of each sealing layer 12 is within the above range, and it is more preferable that the application amount of all layers of the sealing layer 12 is within the above range.

[0034] The thickness of the sealing layer 12 is preferably 0.5 μm or more and 50 μm or less. The lower limit of this thickness is more preferably 1 μm or more. Furthermore, the lower limit of this thickness is more preferably 10 μm or less. By controlling the lower limit of this thickness within this range, the penetration of the release agent described later into the paper substrate 11 can be effectively suppressed. Also, by controlling the upper limit of this thickness within this range, it is possible to keep it at a practical thickness, preventing it from becoming unnecessarily thick.

[0035] The sealing layer 12 may be a single layer or a multi-layered layer of two or more. If the sealing layer 12 consists of multiple layers, these layers may be identical or different, and there are no particular limitations on the combination of these layers. Among these, it is preferable that the sealing layer 12 consists of two or more layers. Having multiple layers in the sealing layer 12 makes it easier to achieve both the effect of effectively suppressing the penetration of the release agent into the paper substrate 11 and the effect of obtaining a smooth surface for the release agent layer.

[0036] The coating method for the sealing layer 12 is not particularly limited and can be applied using known coating equipment and coating systems. For example, coating equipment includes blade coaters, bar coaters, air knife coaters, curtain coaters, spray coaters, roll coaters, reverse roll coaters, size press coaters, gate roll coaters, size press coaters, shimsizers, etc. Coating systems include water-based coating using solvents such as water, and solvent-based coating using solvents such as organic solvents. Furthermore, the drying method for the sealing layer 12 is not particularly limited and can be conventionally used, such as steam heaters, gas heaters, infrared heaters, electric heaters, hot air heaters, microwaves, and cylinder dryers.

[0037] <Release paper> Figure 2 is a schematic cross-sectional view of the release paper according to this embodiment.

[0038] The release paper 20 according to this embodiment includes a paper substrate 11 and a release agent layer 21 laminated on at least a portion of the surface of a release paper base paper 10 which has a sealing layer 12 laminated on at least a portion of the surface of the paper substrate 11. By providing the release agent layer 21 on the surface of the sealing layer 12, it can be suitably used as release paper 20. From an environmental viewpoint, it is preferable that the release paper 20 does not have a layer containing polyolefin (polyolefin layer). This polyolefin layer is a layer that contains a total of 50% by mass or more of polyolefin in the layer. This makes it possible to meet the above-mentioned requirements for "plastic reduction" and recyclability.

[0039] Furthermore, the release paper 20 may be a double-sided release paper by providing the sealing layer 12 and the release agent layer 21 on both sides of the paper substrate 11. In addition, the release paper 20 may have a curl suppression layer (not shown) or the like on the side of the paper substrate 11 opposite to the side where the sealing layer 12 and the release agent layer 21 are provided. The curl suppression layer is not particularly limited and any known layer can be used.

[0040] (Release agent layer) The release agent contained in the release agent layer 21 is not particularly limited, and examples include silicone resins, fluororesins, alkyd resins, long-chain alkyl resins, and various waxes. Among these, a silicone resin is preferred as the release agent from the viewpoint of excellent release properties.

[0041] The release agent layer 21 can be formed by curing a coating solution containing the above-mentioned release agent on a portion of the surface of the sealing layer 12 by applying and heating it. The coating method is not particularly limited, and various coating devices such as blade coaters, air knife coaters, rod blade coaters, bar blade coaters, gravure coaters, bar coaters, and multi-stage roll coaters can be appropriately selected and used for coating.

[0042] The amount of release agent to be applied is 0.4 g / m² by dry weight. 2 More than 3.0g / m 2 The following is preferable. The lower limit of this coating amount is 0.6 g / m². 2 It is more preferable that the value be greater than or equal to 0.8 g / m 2 It is even more preferable that the amount applied is 2.0 g / m². 2 It is more preferable that the following conditions apply: 1.8 g / m 2 The following is even more preferable. By controlling the amount of coating within this range, a more suitable peeling force can be achieved for the release paper 20.

[0043] <Adhesive tape> Figure 3 is a schematic cross-sectional view of the adhesive tape according to this embodiment.

[0044] The adhesive tape 30 according to this embodiment includes the release paper 20 described above, an adhesive layer 32 provided on the surface of the release paper 20, and a tape base material 31 laminated on the surface of the adhesive layer 32 opposite to the release paper 20. Note that the adhesive layer 32 only needs to be formed on at least a part of the surface of the tape base material 31. The adhesive tape 30 can be suitably used by laminating the tape base material 31 to the surface of the release layer 21 of the release paper 20 via the adhesive layer 32. That is, the adhesive tape 30 is made by laminating a paper base material 11, a sealing layer 12, a release layer 21, an adhesive layer 32, and a tape base material 31 in this order.

[0045] (Tape base material) The tape base material 31 can be appropriately selected from paper-based, resin-based, or other raw materials depending on the application and environment. The thickness of the tape base material 31 is not particularly limited, but is generally 100 μm or less. From the perspective of reducing waste and improving transportation costs, thinner adhesive tapes 30 are desirable; therefore, the thickness of the tape base material 31 is preferably 1 μm to 30 μm, and more preferably 2 μm to 15 μm. If the thickness of the tape base material 31 is less than 1 μm, the handling properties and processability of the adhesive tape 30 may decrease.

[0046] (Adhesive layer) The adhesive contained in the adhesive layer 32 is not particularly limited and includes, for example, rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, epoxy-based adhesives, polyester-based adhesives, urethane-based adhesives, polyolefin-based adhesives, vinyl ether-based adhesives, etc. It may also be a solvent-free adhesive such as a solvent-type adhesive, emulsion-type adhesive, or hot-melt-type adhesive, or an energy-ray-curing adhesive that hardens and becomes re-peelable upon irradiation with energy rays. Furthermore, the adhesive may contain crosslinking agents, tackifiers, softeners, anti-aging agents, fillers, colorants such as dyes or pigments, etc., as needed.

[0047] The thickness of the adhesive layer 32 is not particularly limited, but is preferably 1 μm or more and 100 μm or less. From the viewpoint of reducing waste and improving transportation costs, it is desirable for the adhesive tape 30 to be thinner, so the thickness of the adhesive layer 32 is more preferably 50 μm or more, preferably 20 μm or less, and more preferably 15 μm or less. In addition, a print-receiving layer and a print layer (neither shown) may be provided on the surface of the tape substrate 31 opposite to the adhesive layer 32 (the outermost surface). Furthermore, a conventionally known laminate film (not shown) may be provided on the surface of the adhesive tape 30 to protect the adhesive tape 30 and prevent discoloration.

[0048] The adhesive tape 30 can be manufactured by applying a coating liquid containing an adhesive to the surface of the release agent layer 21 of the release paper 20 described above using a known method, drying it to form an adhesive layer 32, and then laminating the tape base material 31 onto the adhesive layer 32. Furthermore, if necessary, a winding process for winding the adhesive tape 30 may be performed.

[0049] The adhesive tape 30 can be molded into various forms such as sheets, tapes, or labels and used for various purposes similar to conventional adhesive tapes, such as bonding objects to a substrate. The adhesive tape 30 can be suitably used as various labels for overlaminating, as well as for management purposes (e.g., labels for inventory management, process management, logistics management, etc.), stationery and office supplies (concealment labels, fancy labels, etc.), sales promotion and advertising, and various other applications such as toys. [Examples]

[0050] The present invention will be described in more detail by the following examples and comparative examples, but the present invention is not limited in any way by the following examples.

[0051] In this embodiment, the processing and measurements were carried out under conditions of 23°C and 50% relative humidity, unless otherwise specified.

[0052] <Example 1> Using a pulp slurry made by mixing 20% ​​by mass of beaten hardwood bleached kraft pulp (LBKP) and 80% by mass of softwood bleached kraft pulp (NBKP) as raw materials, papermaking is carried out, and an acrylic emulsion of 2.0 g / m² is applied to both outer layers during sizing press. 2 The material is impregnated to achieve a (solids content) ratio, and then calendered to a basis weight of 19 g / m². 2 The paper has a thickness of 25 μm and a density of 0.76 g / cm³. 3 A paper substrate was obtained.

[0053] The longitudinal tensile strength of the obtained paper substrate was measured according to the method specified in JIS P8113 and was found to be 2.0 kN / m or higher.

[0054] Next, a coating liquid for sealing the pores, consisting of 100 parts by mass of polyvinyl alcohol and 550 parts by mass of water, is applied at a dry weight of 2.0 g / m². 2 The mixture was applied in this manner and dried to form a sealing layer. Subsequently, a silicone-based release agent was applied to the sealing layer at a rate of 2.0 g / m² by dry weight. 2 The material was applied in this manner and cured at 150°C for 30 seconds to form a release agent layer and obtain release paper.

[0055] Next, an acrylic adhesive composition was applied to the release paper and dried to form an adhesive layer (10 μm thick). The surface of the adhesive layer was then bonded to a PET substrate (12 μm thick) to produce an adhesive tape.

[0056] <Example 2> Except for the fact that the mixture consisted of 40% polyester fiber by weight, 25% by mass of beaten hardwood bleached kraft pulp (LBKP), and 35% by mass of softwood bleached kraft pulp (NBKP), a paper substrate (basis weight 19 g / m²) was prepared in the same manner as in Example 1, in addition to being a pulp slurry. 2 The paper has a thickness of 18 μm and a density of 1.05 g / cm³. 3 A material was obtained, and an adhesive tape was prepared. The longitudinal tensile strength of the obtained paper substrate was measured according to the method specified in JIS P8113 and was found to be 2.0 kN / m or more.

[0057] <Example 3> The raw material is a pulp slurry made by mixing 50% by mass of beaten hardwood bleached kraft pulp (LBKP) and 50% by mass of softwood bleached kraft pulp (NBKP). Furthermore, 10 parts by mass (in terms of solid content) of polyamine resin (Seiko PMC, WS-4011), which has been pre-activated with sodium hydroxide, is added per 100 parts by mass of pulp, and the paper is manufactured on a paper machine with a basis weight of 15 g / m². 2 The paper is prepared in this manner, and during the size press, an acrylic emulsion is applied to both outer layers at a rate of 2.0 g / m². 2 Impregnation is performed to achieve a basis weight of 19 g / m² (based on solid content). 2 The paper has a thickness of 18 μm and a density of 1.05 g / cm³. 3 A paper substrate was obtained. Furthermore, an adhesive tape was prepared in the same manner as in Example 1. The longitudinal tensile strength of the obtained base paper was measured according to the method specified in JIS P8113 and was found to be 2.0 kN / m or higher.

[0058] <Comparative Example 1> The raw material is a pulp slurry made by mixing 90% by mass of beaten hardwood bleached kraft pulp (LBKP) and 10% by mass of softwood bleached kraft pulp (NBKP), with a basis weight of 19 g / m². 2 A paper substrate with a thickness of 18 μm was obtained. Adhesive tape was then prepared in the same manner as in Example 1. The longitudinal tensile strength of the obtained base paper was measured according to the method specified in JIS P8113 and was found to be less than 2.0 kN / m.

[0059] The release papers obtained in Examples 1-3 had low basis weight but excellent handling properties as adhesive tapes. On the other hand, the release paper obtained in Comparative Example 1 had low tensile strength and therefore poor handling properties.

[0060] Based on the above, it has been confirmed that, according to this embodiment, a release paper base material can be obtained that has a low basis weight, good handling properties, and good processability when used as an adhesive tape. [Explanation of symbols]

[0061] 10: Release liner base paper 11:Paper base material 12: Sealing layer 20: Release paper 21: Release agent layer 30: Adhesive tape 31: Tape base material 32: Adhesive layer

Claims

1. The invention comprises a paper substrate and a sealing layer laminated on at least a portion of the surface of the paper substrate, The aforementioned paper substrate is 20 g / m ２ Grammage less than, Having a paper thickness of less than 35 μm, The longitudinal tensile strength measured in accordance with JIS P 8113:2006 is 2.0 kN / m or more. The aforementioned paper substrate contains wood pulp and plastic fibers. The wood pulp content is 50% by mass or more and 100% by mass or less of the total mass of the paper substrate, and the weight ratio of the plastic fibers to the wood pulp is 10:90 to 49:

51. A release paper base characterized by the following features.

2. The aforementioned paper substrate includes softwood pulp and hardwood pulp. The release paper base according to claim 1, characterized in that the weight mixing ratio of the softwood pulp to the hardwood pulp is 50:50 to 100:

0.

3. A paper substrate and a sealing layer laminated on at least a portion of the surface of the paper substrate, The aforementioned paper substrate is Basis weight of less than 20 g / m², Having a paper thickness of less than 35 μm, The longitudinal tensile strength measured in accordance with JIS P 8113:2006 is 2.0 kN / m or more. The aforementioned paper substrate is characterized by containing a wet paper strength enhancer in an amount of 0.5% by mass or more and 20% by mass or less relative to the total mass of the raw pulp.

4. A paper substrate and a sealing layer laminated on at least a portion of the surface of the paper substrate, The aforementioned paper substrate is Basis weight of less than 20 g / m², Having a paper thickness of less than 35 μm, The longitudinal tensile strength measured in accordance with JIS P 8113:2006 is 2.0 kN / m or more. The aforementioned paper substrate is treated with a resin-containing processing solution using a size press, at a rate of 1.0 g / m² per side. ２ 5.0g / m or more ２ Release paper base characterized by being coated or impregnated with the following (calculated on dry solids content).

5. A release paper base according to any one of claims 1 to 4, A release agent layer laminated on at least a portion of the surface of the release paper base, Release paper characterized by containing [the following].

6. Tape base material and An adhesive layer laminated on at least a portion of the surface of the tape substrate, The release paper according to claim 5 is laminated on the surface of the adhesive layer opposite to the tape substrate, An adhesive tape characterized by containing [the following].

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