JP2024024488A - Release paper base paper, release paper and adhesive tape - Google Patents

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

The present invention relates to a release paper base paper, a release paper, and an adhesive tape.

The release paper is a member that protects the adhesive layer of the adhesive tape and prevents the adhesive from decreasing. In recent years, from the perspective of reducing environmental impact, there has been a demand for reduced plastic waste and recyclability. In particular, there is an increasing 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 base material as much as possible and maximize its releasability (for example, (See Patent Document 1). Furthermore, from the viewpoint of reducing waste and improving transportation costs, it is desired to reduce the basis weight of release paper.

Japanese Patent Application Publication No. 2012-201990

However, even if the basis weight of the release paper is simply lowered, the tensile strength of the release paper decreases, and processing suitability such as tearing of the release paper during the step of peeling the release paper when used as an adhesive tape decreases. Therefore, there was a tendency to avoid excessively low basis weight of the release paper.

Therefore, the main object of the present disclosure is to provide a release paper base paper, a release paper, and an adhesive tape that have a low basis weight, are easy to handle, and have good processability when made into an adhesive tape.

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

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, are easy to handle, and have good processability when made into an adhesive tape.

FIG. 1 is a schematic cross-sectional view of a release paper base paper according to this embodiment. FIG. 2 is a schematic cross-sectional view of the release paper according to this embodiment. FIG. 3 is a schematic cross-sectional view of the adhesive tape according to this embodiment.

Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail. The present embodiment below is an illustration for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be implemented with appropriate modifications within the scope of its gist.

In the drawings, the same elements are denoted by the same reference numerals, and redundant explanations will be omitted. In addition, the positional relationships such as top, bottom, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

<Release paper base paper>
FIG. 1 is a schematic cross-sectional view of a release paper base paper according to this embodiment.

The release paper base paper 10 according to this embodiment includes a paper base material 11 and a sealing layer 12 laminated on at least a portion of the surface of the paper base material 11. Further, the paper base material 11 has a basis weight of less than 20 g/m ² and a paper thickness of less than 35 μm, and has a longitudinal tensile strength of 2.0 kN/m measured in accordance with JIS P 8113:2006. That's all. With this configuration, it is possible to obtain a release paper base paper 10 that has a low basis weight, has good handling properties, and has good processability when made into an adhesive tape.

(Basic weight of paper base material)
The basis weight of the paper base material 11 is less than 20 g/m ² . Further, the lower limit of the basis weight of the paper base material 11 is preferably 5 g/m ² or more, more preferably 10 g/m ² or more from the viewpoint of processability.

(Thickness of paper base material)
The paper thickness of the paper base material 11 is measured in accordance with "Paper and paperboard - Test method for thickness and density" described in JIS P8118 (2014). The lower limit of the thickness of the paper base material 11 is preferably 10 μm, more preferably 15 μm. The upper limit of the thickness of the paper base material 11 is 35 μm or less, more preferably 25 μm, and more preferably 20 μm. When the paper thickness of the paper base material 11 is within the above range, the density of the paper base material 11 becomes high, effectively suppressing the penetration of the release agent into the release paper base paper 10, and reducing the basis weight and weight of the release agent. It is possible to maintain strength while making it possible to As a result, workability and processing suitability when producing a release paper using the release paper base paper 10 and processing suitability when peeling the release paper from an adhesive tape can be improved. When producing paper with a thickness within the above range, it is desirable to perform calendering.

Calendaring is a process that equalizes smoothness and thickness by passing paper between rolls. By undergoing calendering, the density of the paper base material 11 increases. Examples of calender processing devices include machine calenders, soft nip calenders, super calenders, multi-stage calenders, and multi-nip calenders.

(Tensile strength in longitudinal direction of paper base material)
The tensile strength in the machine direction (MD) direction of the paper base material 11 is measured in accordance with JIS P 8113:2006 (Paper and paperboard - Test method for tensile properties). The test piece used is one cut to approximately 25 mm (±0.5 mm) in the horizontal direction and 150 mm in the vertical direction. The distance between the grips of the tensile tester is 100 mm, and the measurement is performed by pulling in the longitudinal direction at a tensile speed of 300 mm/min. The tensile speed is 300 mm/min. Five sets of samples are prepared and each sample is measured five times, and the average of the measured values is taken as the longitudinal tensile strength. The longitudinal tensile strength of the paper base material 11 is 2.0 kN/m or more. Further, the tensile strength is preferably 5 kN/m or less, more preferably 4 kN/m or less.

Examples of the pulp constituting the paper base material 11 include wood pulps such as softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), and hardwood bleached 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, such as softwood bleached kraft pulp (NBKP), softwood unbleached kraft pulp (NUKP), softwood semi-bleached kraft pulp (NSBKP), softwood sulfite pulp, and hardwood bleached kraft pulp ( LBKP), hardwood unbleached kraft pulp (LUKP), hardwood semi-bleached kraft pulp (LSBKP), hardwood sulfite pulp, and other chemical pulps, stone ground pulp (SGP), pressed stone ground pulp (TGP), chemical ground pulp ( Examples include mechanical pulps such as CGP), groundwood pulp (GP), and thermomechanical pulp (TMP). In addition, as the non-wood pulp, cotton pulp, hemp, bagasse, kenaf, esparto, mulberry, mitsumata, gampi, etc. can be used as appropriate.

In order to obtain the paper base material 11 having a basis weight of less than 20 g/ ^m2 and a longitudinal tensile strength of 2.0 kN/m or more, the paper base material 11 contains softwood pulp and hardwood pulp, and contains softwood pulp and hardwood pulp. The weight ratio (solid content weight) is preferably 50:50 to 100:0, more preferably 80:20 to 99:1, and more preferably 90:10 to 99:1. A weight ratio (solid content weight) of 1 is more preferred.

Moreover, in the paper base material 11, it is preferable that wood pulp is the main component. Specifically, the content of 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 the paper base material 11 is a mixed paper containing plastic fibers. In this case, in order to obtain the paper base material 11 having a basis weight of less than 20 g/m ² and a longitudinal tensile strength of 2.0 kN/m or more, the wood pulp content should be 50% by mass or more and 100% by mass or less. At the same time, the weight blending ratio of plastic fibers and wood pulp is preferably 10:90 to 49:51 (solid weight), more preferably 35:65 to 45:55.

Examples of plastic fibers include esters, polyethylene terephthalate (PET), polyamide (PA), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polycarbonate (PC), and polyether ether. Preferably it is selected from the group comprising ketones (PEEK), polyisobutylene (PIB), polybutylene (PB), mixtures thereof and copolymers thereof.

In addition, in order to obtain the paper base material 11 having a basis weight of less than 20 g/m ² and a longitudinal tensile strength of 2.0 kN/m or more, 0.5 of the wet paper strength agent is added to the total mass of the raw material pulp. The content is preferably 5% by mass or more and 15% by mass or less, more preferably 5% by mass or more and 15% by mass or less. As the wet paper strength agent, for example, polyamide-polyamine epichlorohydrin resin, urea-formaldehyde resin, epoxidized polyamide resin, melamine-formaldehyde resin, urea-formaldehyde resin, etc. can be used.

Further, in order to obtain a paper base material 11 having a basis weight of less than 20 g/m ² and a longitudinal tensile strength of 2.0 kN/m or more, a resin-containing treatment liquid of 1.0 kN/m per side was applied using a size press. It is preferably coated or impregnated with 0 g/m ² or more and 5.0 g/m ² or less (in terms of dry solid content), and coated or impregnated with 1.5 g/m ² or more and 2.5 g/m ² or less per side. is more preferable. Examples of resin materials include various polyvinyl alcohols, cellulose derivatives such as hydroxyethyl cellulose and carboxymethyl cellulose, polyacrylamide, polyethylene oxide, polypropylene oxide, starch, modified starch, polyacrylic acid, sodium polyacrylate, and water-soluble materials such as casein. Binder, polyethylene, polypropylene, polyisobutylene, polystyrene, polyacrylamide, polyethyl acrylate, polymethyl methacrylate, polyacrylonitrile, polybutadiene, polyisoprene, polyethylene terephthalate, melamine resin, epoxy resin, alkyd resin, unsaturated polyester resin, styrene - Emulsion type binder or emulsion type such as butadiene copolymer, modified styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic ester-methacrylic ester copolymer, etc. A certain urethane resin binder or the like can be used.

The paper base material 11 may include cellulose nanofibers. By including cellulose nanofibers in the paper base material 11, it is possible to improve the glossiness of the paper base material 11 and improve the yield in the paper manufacturing process.

Cellulose nanofibers are single microfibrils of cellulose obtained by fibrillating cellulose raw materials, and have an average fiber diameter of less than 500 nm. A specific method for constructing the material to contain cellulose nanofibers may be a method of manufacturing by adding cellulose nanofibers internally or externally.

In addition to the pulp and the above-mentioned wet paper strength enhancer, the paper base material 11 also contains fillers, sizing agents, bulking agents, retention improvers, freeness improvers, sulfuric acid, colored dyes, colored pigments, and optical brighteners. Various auxiliary agents such as a fluorescent agent, a fluorescent decolorizer, a pH adjuster, an antifoaming agent, a pitch control agent, and a slime control agent can be contained as necessary. These may be used alone or in combination of two or more.

The density of the paper base material 11 is preferably 0.5 g/cm ³ or more and 2.0 g/cm ³ or less, more preferably 0.6 g/cm ³ or more and 1.5 g/cm ³ or less, and 0.7 g/cm ³ or more. More preferably, it is 1.3 g/cm ³ or less. If the density is less than 0.5 g/cm ³ , the release agent will penetrate to a large extent and the releasability will deteriorate. Additionally, there is a risk that the release agent may escape to the opposite side. On the other hand, if the density exceeds 2.0 g/cm ³ , the smoothness will be too high and the paper will become slippery when coated with a release agent.

The method of manufacturing the paper base material 11, the method of making the paper, the type of paper machine, etc. are not particularly limited. For example, known manufacturing (paper making) methods such as fourdrinier paper machines, cylinder paper machines, short wire paper machines, gap former type, hybrid former type (on-top former type) twin wire paper machines, etc. Machines can be selected. Furthermore, the pH during papermaking is not particularly limited, and may be in any of the acidic region (acidic papermaking), pseudo-neutral region (pseudo-neutral papermaking), neutral region (neutral papermaking), and alkaline region (alkaline papermaking). After papermaking in an acidic region, an alkaline chemical may be applied to the surface of the paper layer. Moreover, the paper base material 11 may be one layer, or may be composed of two or more layers.

(filling layer)
The sealing layer 12 is for effectively suppressing the penetration of the release agent into the paper base material 11 and providing smoothness of the surface of the release agent layer. In addition, from the viewpoint of reducing environmental load, it is preferable that the sealing layer 12 does not contain polyolefin. If the sealing layer 12 is a polyolefin-free sealing layer, it can fully meet the above-mentioned demands for "free plastic" and recyclability.

It is preferable that the sealing layer 12 contains a binder resin. The binder resin is not particularly limited, and any binder resin that can be used in the coated paper field can be used as appropriate. Examples of the binder resin include 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, and butyral-modified polyvinyl alcohol. Polyvinyl alcohol resins such as alcohol, olefin-modified polyvinyl alcohol, nitrile-modified polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol, silicone-modified polyvinyl alcohol, and other modified polyvinyl alcohol; methyl methacrylate-butadiene copolymer, (meth)acrylic acid, and ( Acrylic resins consisting of monomer components (excluding olefins) copolymerizable with meth)acrylic acid; Cellulose derivatives such as hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and acetyl cellulose; oxidized starch, etherified starch, and esterified starch Starches such as starch; styrenic resins such as styrene-maleic anhydride copolymer, styrene-butadiene copolymer, styrene-acrylic copolymer; casein, gum arabic, polyvinyl chloride, polyvinyl acetate, polyacrylamide, Polyacrylic acid ester, polyvinyl butyral, polystylose and their copolymers, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, coumaron resin, dextrin, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate Copolymers and the like can be mentioned. Among these, at least one selected from the group consisting of polyvinyl alcohol resins, starches, and styrene resins is preferred. Then, polyvinyl alcohol (fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol), oxidized starch, and styrenic copolymers (styrene-maleic anhydride copolymer, styrene-butadiene copolymer, styrene-acrylic copolymer) It is more preferable that it is at least one selected from the group consisting of (etc.). These may be used alone or in combination of two or more.

The sealing layer 12 preferably contains an inorganic pigment, and more preferably contains the above-described binder resin and an inorganic pigment. 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, and 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, and the like. Among these, one type selected from the group consisting of kaolin, calcined kaolin, and engineered kaolin is preferable, and kaolin is more preferable. These may be used alone or in combination of two or more.

The content of the inorganic pigment is not particularly limited, but from the viewpoint of smoothness and binding property, it is preferably 1 part by mass or more and 1400 parts by mass or less based on 125 parts by mass of the binder resin in terms of dry weight, and preferably 200 parts by mass. It is more preferably 600 parts by mass or less, still more preferably 250 parts by mass or more and 500 parts by mass or less, even more preferably 300 parts by mass or more and 400 parts by mass or less.

The sealing layer 12 may contain a sizing agent, a water resistance agent, a water repellent, a dye, a surfactant, a dispersant, a thickener, a water retention agent, an antifoaming agent, a water resistance agent, a dye, a fluorescent dye, or Various commonly used auxiliary agents such as crosslinking agents can be included.

The coating amount of the sealing layer 12 is preferably 0.2 g/m ² or more and 20 g/m ² or less in terms of dry weight. The coating amount is more preferably 0.5 g/m ² or more, and even more preferably 0.7 g/m ² or more. Moreover, the upper limit of this coating amount is more preferably 10 g/m ² or less, and even more preferably 8 g/m ² or less. By setting the coating amount of the sealing layer 12 to the above lower limit value or more, the penetration of the release agent into the paper base material 11 can be more effectively suppressed, and the smoothness of the surface of the release agent layer can be further improved. I can do it. On the other hand, by controlling the coating amount of the sealing layer 12 to be less than or equal to the above upper limit value, the drying load during coating can be further reduced, and the operational and cost aspects are also more favorable. In addition, when the sealing layer 12 is a plurality of layers of two or more layers, it is preferable that the coating amount of at least one layer of each sealing layer 12 is within the above range, and the coating amount of all the layers of the sealing layer 12 is preferably within the above range. It is more preferable that the amount is within the above range.

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. Moreover, it is more preferable that this thickness is 10 μm or less. By controlling the lower limit of this thickness within such a range, it is possible to effectively suppress penetration of a release agent, which will be described later, into the paper base material 11. Furthermore, by controlling the upper limit of the thickness within this range, it is possible to prevent the thickness from becoming unnecessarily thick and to keep it at a practical thickness.

The sealing layer 12 may have only one layer (single layer), or may have two or more layers. When the sealing layer 12 has multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited. Among these, it is preferable that the sealing layer 12 is composed of two or more layers. Since the sealing layer 12 has multiple layers, it becomes easier to achieve both the effect of effectively suppressing the penetration of the release agent into the paper base material 11 and the effect of obtaining smoothness of the surface of the release agent layer.

The coating method for the sealing layer 12 is not particularly limited, and coating can be performed using a known coating device and coating system. For example, examples of the coating device include a blade coater, a bar coater, an air knife coater, a curtain coater, a spray coater, a roll coater, a reverse roll coater, a size press coater, a gate roll coater, a size press coater, and a shim sizer. Further, examples of the coating system include water-based coating using a solvent such as water, solvent-based coating using a solvent such as an organic solvent, and the like. Further, the method for drying the sealing layer 12 is not particularly limited, and for example, ordinary methods such as a steam heater, a gas heater, an infrared heater, an electric heater, a hot air heater, a microwave, a cylinder dryer, etc. can be used. .

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

The release paper 20 according to the present embodiment includes a paper base material 11 and a sealing layer 12 laminated on at least a part of the surface of the paper base material 11. agent layer 21. By providing a release agent layer 21 on the surface of the sealing layer 12, it can be suitably used as a release paper 20. Note that, from an environmental standpoint, the release paper 20 preferably does not have a layer containing polyolefin (polyolefin layer). This polyolefin layer is a layer containing 50% by mass or more of polyolefin in total. This makes it possible to meet the above-mentioned demands for "free plastic" and recyclability.

Note that 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 base material 11. Furthermore, the release paper 20 may be provided with a curl suppressing layer (not shown) or the like on the surface of the paper base material 11 opposite to the surface on which the sealing layer 12 and the release agent layer 21 are provided. The curl suppressing layer is not particularly limited, and any known layer can be used.

(Release agent layer)
The release agent contained in the release agent layer 21 is not particularly limited, and examples thereof include release agents such as silicone resins, fluororesins, alkyd resins, long-chain alkyl resins, and various waxes. Among these, from the viewpoint of excellent releasability, the release agent is preferably a silicone resin.

The release agent layer 21 can be formed by applying a coating liquid containing the above-mentioned release agent to a part of the surface of the sealing layer 12 and heating and curing the coating liquid. The coating method is not particularly limited, and for example, a coating method may be employed by appropriately selecting various coating devices such as a blade coater, air knife coater, rod blade coater, bar blade coater, gravure coater, bar coater, multi-stage roll coater, etc. can do.

The coating amount of the release agent is preferably 0.4 g/m ² or more and 3.0 g/m ² or less in terms of dry weight. The lower limit of this coating amount is more preferably 0.6 g/m ² or more, and even more preferably 0.8 g/m ² or more. Further, the coating amount is more preferably 2.0 g/m ² or less, and even more preferably 1.8 g/m ² or less. By controlling the coating amount within such a range, it is possible to obtain a release force more suitable for the release paper 20.

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

The adhesive tape 30 according to the present embodiment includes the above-mentioned release paper 20, an adhesive layer 32 provided on the surface of the release paper 20, and a surface of the adhesive layer 32 on the opposite side to the release paper 20. It includes a laminated tape base material 31. Note that the adhesive layer 32 only needs to be formed on at least a portion of the surface of the tape base material 31. By laminating the tape base material 31 to the surface of the release agent layer 21 of the above-mentioned release paper 20 via the adhesive layer 32, it can be suitably used as the adhesive tape 30. That is, the adhesive tape 30 has a paper base material 11, a sealing layer 12, a release agent layer 21, an adhesive layer 32, and a tape base material 31 laminated in this order.

(tape base material)
As the tape base material 31, a base material made of paper-based, resin-based, or other raw materials can be appropriately selected depending on the application and environment. Further, the thickness of the tape base material 31 is not particularly limited, and is generally 100 μm or less. Since the adhesive tape 30 is desired to be thinner from the viewpoint of reducing waste and improving transportation costs, the thickness of the tape base material 31 is preferably 1 μm or more and 30 μm or less, more preferably 2 μm or more and 15 μm or less. When the thickness of the tape base material 31 is less than 1 μm, the handleability and processability of the adhesive tape 30 may deteriorate.

(Adhesive layer)
The adhesive included in the adhesive layer 32 is not particularly limited, and includes, for example, a rubber adhesive, an acrylic adhesive, a silicone adhesive, an epoxy adhesive, a polyester adhesive, a urethane adhesive, and a polyolefin. Examples include vinyl ether type adhesives and vinyl ether type adhesives. It may also be a solvent-free adhesive such as a solvent-based adhesive, an emulsion-type adhesive, a hot-melt adhesive, or an energy-ray-curable adhesive that is cured by irradiation with energy rays and becomes removable. Furthermore, the adhesive may contain a crosslinking agent, a tackifier, a softener, an anti-aging agent, a filler, a coloring agent such as a dye or a pigment, etc., if necessary.

The thickness of the adhesive layer 32 is not particularly limited, and is preferably 1 μm or more and 100 μm or less. From the viewpoint of reducing waste and improving transportation costs, the adhesive tape 30 is also desired to be thin, 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. Note that a print-receiving layer, a print layer (both not shown), etc. may be further provided on the surface of the tape base material 31 opposite to the adhesive layer 32 (the surface of the outermost layer). Further, a conventionally known laminate film (not shown) may be further provided on the surface of the adhesive tape 30 in order to protect the adhesive tape 30 and prevent discoloration.

The adhesive tape 30 is made by applying a coating liquid containing an adhesive to the surface of the release agent layer 21 of the release paper 20 described above by a known method, drying it to form an adhesive layer 32, and then applying the adhesive layer 32. It can be manufactured by laminating the tape base material 31 thereon. Furthermore, a winding process of winding the adhesive tape 30 or the like may be performed as necessary.

The adhesive tape 30 can be formed into an appropriate form such as a sheet, tape, or label and used for various purposes similar to conventional adhesive tapes, such as adhesion of adherends. The adhesive tape 30 can be used, for example, for various overlaminate labels, for management purposes (for example, goods management labels, process management labels, logistics management labels, etc.), stationery and office supplies (blind labels, fancy labels, etc.), It can be suitably used as various labels for sales promotion, advertising, and various other uses for play equipment.

The present invention will be explained in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to the following Examples.

It should be noted that the treatments and measurements in this example were performed in an environment of 23° C. and 50% relative humidity unless otherwise specified.

<Example 1>
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) is used as a raw material to make paper, and in a size press, 2.0% of acrylic emulsion is applied to both outer layers. It was impregnated to a concentration of 0 g/m ² (in terms of solid content), and then calendered to obtain a paper base having a basis weight of 19 g/m ² , a paper thickness of 25 μm, and a density of 0.76 g/cm ³ .

The tensile strength in the longitudinal direction of the obtained paper base material was measured based on the method specified in JIS P8113, and was found to be 2.0 kN/m or more.

Next, a sealing layer coating liquid consisting of 100 parts by mass of polyvinyl alcohol and 550 parts by mass of water was applied so that the coating amount was 2.0 g/m ² by dry weight, and the sealing layer was formed by drying. did. Thereafter, a silicone release agent is applied onto the sealing layer at a dry weight coating amount of 2.0 g/m ² and cured at 150° C. for 30 seconds to form a release agent layer. A release paper was obtained.

Next, an acrylic adhesive composition is applied onto the release paper and dried to form an adhesive layer (thickness: 10 μm), and the surface of the adhesive layer is bonded to a PET base material (thickness: 12 μm) to form an adhesive tape. was created.

<Example 2>
A paper base was prepared in the same manner as in Example 1, except that 40% by weight of polyester fibers, 25% by weight of beaten hardwood bleached kraft pulp (LBKP), and 35% by weight of softwood bleached kraft pulp (NBKP) were blended to form a pulp slurry. A material (basis weight: 19 g/m ² , paper thickness: 18 μm, density: 1.05 g/cm ³ ) was obtained, and an adhesive tape was produced. In addition, when the longitudinal tensile strength of the obtained paper base material was measured based on the method specified in JIS P8113, it was 2.0 kN/m or more.

<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), and a polyamine resin (Seiko PMC) activated with sodium hydroxide in advance. WS-4011) (manufactured by WS-4011) was blended with 100 parts by mass of pulp in terms of solid content, and the paper was made with a paper machine to have a basis weight of 15 g/ ^m2.In the size press, both outer layers were made of acrylic A paper base material having a basis weight of 19 g/m ² , a paper thickness of 18 μm, and a density of 1.05 g/cm ³ was obtained by impregnating the base emulsion to a concentration of 2.0 g/m ² (in terms of solid content). In addition, an adhesive tape was produced in the same manner as in Example 1. The longitudinal tensile strength of the obtained base paper was measured in accordance with the method specified in JIS P8113, and was found to be 2.0 kN/m or more.

<Comparative example 1>
A paper base material with a basis weight of 19 g/m ² and a paper thickness of 18 μm, made from 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). I got it. In addition, an adhesive tape was produced in the same manner as in Example 1. The longitudinal tensile strength of the obtained base paper was measured in accordance with the method specified in JIS P8113, and was found to be less than 2.0 kN/m.

Although the release papers obtained in Examples 1 to 3 had low basis weight, they had excellent handling properties as adhesive tapes. On the other hand, the release paper obtained in Comparative Example 1 had low tensile strength and was inferior in handleability.

From the above, it was at least confirmed that according to this example, a release paper base paper having a low basis weight, good handling properties, and good processing suitability when made into an adhesive tape was obtained.

10: Release paper 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 (7)

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