JP2020133023A - Base paper for release paper and release paper - Google Patents

Abstract

To provide base paper for release paper capable of directly coating a solvent-based silicone resin or the like as a release agent without laminating a resin such as polyethylene or the like on the base paper, and to provide the release paper having excellent adhesiveness, releasability, and disaggregation property, obtained by coating the base paper for release paper with said release agent.SOLUTION: In a base paper for release paper comprising a base paper, at least one surface of which is provided with a sealing layer containing at least a pigment component and an adhesive component, the pigment component contains an inorganic pigment A having an aspect ratio of 10 or more and an inorganic pigment B having an aspect ratio of less than 10, the blending ratio of the inorganic pigment A to the inorganic pigment B is 95/5 to 50/50 by mass, the adhesive component contains at least a synthetic resin latex, and the blending amount of the synthetic resin latex with respect to 100 pts.mass of the pigment components is 20 to 50 pts.mass by absolute dry.SELECTED DRAWING: None

Description

The present invention relates to a release paper base paper used for a release paper used for an adhesive label, an adhesive sticker, an adhesive tape, etc., and in particular, a solvent-based silicone resin which is a release agent without laminating a resin such as polyethylene on the base paper. , A base paper for release paper that can be directly coated with a water-based emulsion-based silicone resin or a solvent-free silicone resin, and excellent adhesion and peelability obtained by applying a release agent to the base paper. , Releasable release paper.

The release paper is used as a mount for protecting the adhesive surface of adhesive labels, adhesive stickers, adhesive tapes, etc. from dust and the like, and a release agent such as silicone resin is used on the surface in contact with the adhesive surface. Is painted.
Conventional release paper is manufactured by applying a release agent to the surface of base paper such as resin laminated paper such as polyethylene, glassin paper, clay coated paper, and clear coated paper. These release agents are made of toluene or the like. Since it is diluted with an organic solvent and used, there is a problem of causing environmental damage.
Therefore, in recent years, there has been an increasing demand for water-based emulsion-type silicone resins and solvent-free silicone resins.

In addition, since the silicone resin used as a release agent is very expensive, the silicone resin coating liquid permeates the inside of the base paper in order to enable uniform coating of a small amount of the silicone resin coating liquid. It is necessary as a characteristic of the base paper for release paper to suppress this as much as possible. In recent years, recyclability has also been required from the viewpoint of resource saving.

In order to suppress the penetration of a release agent such as a silicone resin, a release paper base paper obtained by laminating a resin such as polyethylene on a base paper is preferable, but since it is difficult to separate the release paper after use, it is recyclable. There was a problem of inferiority.

In order to solve the above problem, an invention relating to a recyclable release paper base paper provided with a pigment coating layer composed of a pigment and a synthetic latex in order to prevent the silicone resin coating liquid from penetrating into the base paper has been invented. It is disclosed (Patent Document 1 etc.). However, the permeation of the silicone resin coating liquid was not sufficiently prevented, and it was not possible to obtain a release paper having sufficient adhesion, peelability, and disintegration property.

Japanese Unexamined Patent Publication No. 2000-282397

Therefore, according to the present invention, it is possible to directly apply a solvent-based silicone resin, an aqueous emulsion-based silicone resin, or a solvent-free silicone resin as a release agent without laminating a resin such as polyethylene on the base paper. It is an object of the present invention to provide a base paper for paper and a release paper having excellent adhesion, peelability, and releasability obtained by applying a release agent to the base paper for release paper.

The present invention provides the following [1] to [12].
[1] An inorganic pigment having an aspect ratio of 10 or more as the pigment component, which is a base paper for release paper provided with a sealing layer containing at least a pigment component and an adhesive component on at least one surface of the base paper. It contains A and an inorganic pigment B having an aspect ratio of less than 10, the blending ratio of the inorganic pigment A and the inorganic pigment B is 95/5 to 50/50 by mass, and the adhesive component is at least a synthetic resin. A base paper for release paper, which contains a latex and contains 20 to 50 parts by mass of the synthetic resin latex in an absolute dry state with respect to 100 parts by mass of the pigment component.
[2] The base paper for release paper according to [1], wherein the 50% volume average particle diameter (D50) measured by the laser diffraction / scattering method of the inorganic pigment B is 0.5 to 2.0 μm. ..
[3] The base paper for release paper according to [1] or [2], wherein the inorganic pigment B is calcium carbonate.
[4] The base paper for release paper according to [3], wherein the calcium carbonate is light calcium carbonate.
[5] The base paper for release paper according to any one of [1] to [4], wherein the inorganic pigment A is kaolin.
[6] The base paper for release paper according to any one of [1] to [5], wherein the synthetic resin latex has a glass transition temperature of -20 to 30 ° C.
[7] The base paper for release paper according to any one of [1] to [6], wherein the synthetic resin latex is a styrene-budaziene copolymer latex.
[8] The coating amount of the sealing layer determined from the basis weight difference between the base paper and the base paper for release paper measured based on JIS P 8124: 2011 under the environment of JIS P 8111: 1998 is 8 to 20 g. The base paper for release paper according to any one of [1] to [7], which is characterized by being / m ² . [9] Described in any one of [1] to [8], wherein the surface roughness of the sealing layer surface measured based on JIS B 0601: 1994 is 0.5 to 1.0 μm. Base paper for release paper.
[10] The description according to any one of [1] to [9], wherein the air permeability resistance (Oken type testing machine method) defined in JIS P 8117: 2009 is 100,000 seconds or more. Base paper for release paper.
[11] A release paper having a release agent layer on the sealing layer of the release paper base paper according to any one of [1] to [10], and under the environment of JIS P 8111: 1998, JIS P 8124. : The release amount of the release agent layer determined from the difference in basis weight between the release paper base paper and the release paper measured based on 2011 is 0.5 to 2.0 g / m ^2. paper.
[12] The release paper according to [11], wherein the release agent layer is a silicone resin layer.
In the present invention, "absolute drying" means drying at 105 ° C. for 1 to 2 hours, and hereinafter, the mass parts of the pigment and the synthetic resin latex used in the present invention are referred to as "mass parts after absolute drying". ..

According to the present invention, it is possible to directly apply a solvent-based silicone resin, a water-based emulsion-based silicone resin, or a solvent-free silicone resin as a release agent without laminating a resin such as polyethylene on the base paper. It is possible to provide a base paper for paper and a release paper having excellent adhesion, peelability, and releasability obtained by applying a release agent to the base paper for release paper.

The base paper for release paper of the present invention is provided with a sealing layer containing at least a pigment component and an adhesive component on at least one surface of the base paper, and the inorganic pigment A having an aspect ratio of 10 or more as the pigment component. And an inorganic pigment B having an aspect ratio of less than 10, the blending ratio of the inorganic pigment A and the inorganic pigment B is 95/5 to 50/50 by mass, and the adhesive component is at least a synthetic resin latex. The amount of the synthetic resin latex blended with respect to 100 parts by mass of the pigment component in absolute dryness is 20 to 50 parts by mass in absolute dryness.

(Base paper)
In the present invention, the base paper is a sheet mainly made of pulp, and may contain a filler and various auxiliaries.
Examples of pulp include broadleaf bleached kraft pulp (LBKP), coniferous bleached kraft pulp (NBKP), broadleaf unbleached kraft pulp (LUKP), coniferous unbleached kraft pulp (NUKP), chemical pulp such as sulfite pulp, stone grind pulp, and thermo. Mechanical pulp such as mechanical pulp and refiner grind pulp, wood fiber such as deinked pulp, used paper pulp and recycled pulp, and non-wood fiber obtained from kenaf, bamboo, hemp, etc. can be used, and are appropriately mixed and used. It is possible.

As the filler, known fillers such as white carbon, talc, kaolin, clay, heavy calcium carbonate, light calcium carbonate, titanium oxide, zeolite, and synthetic resin filler can be used. In addition, if necessary, a sulfate band and various anionic, cationic, nonionic, or amphoteric yield improvers, drainage improvers, paper strength enhancers, internal sizing agents, and other papermaking aids are used. Can be used. Further, dyes, fluorescent whitening agents, pH adjusting agents, defoaming agents, pitch control agents, slime control agents and the like can be added as needed.

The method for producing the base paper (papermaking) is not particularly limited, and acidic papermaking and neutral papermaking are used using a known long net former machine, on-top hybrid former machine, gap former machine, yanky machine, or the like. , The base paper can be manufactured by papermaking by the alkaline papermaking method. Further, the base paper may have one layer or may be composed of two or more layers.
Furthermore, the surface of the base paper can be treated with various chemicals. Examples of the chemicals used include oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide, polyvinyl alcohol, surface sizing agents, water resistant agents, water retention agents, thickeners, lubricants, and the like. These can be used alone or in combination of two or more.

The method of surface treatment of the base paper is not particularly limited, but a known coating device such as a rod metering size press, a pound type size press, a gate roll coater, a spray coater, a blade coater, or a curtain coater can be used. it can.
Various base papers obtained in this way include high-quality paper, medium-quality paper, coated paper, single-gloss paper, kraft paper, single-gloss kraft paper, bleached kraft paper, glassin paper, paperboard, white paperboard, and liner. Known ones can be exemplified.

The basis weight of the base paper of the present invention may be any as long as the basis weight which can be used as a base paper or release paper for release paper is generally from 80g / m ² ~300g / m ² approximately, 100g Those of / m ^{2 to} 220 g / m ² are often used.

(Filling layer)
The pigment component contained in the sealing layer of the present invention contains an inorganic pigment A having an aspect ratio of 10 or more and an inorganic pigment B having an aspect ratio of less than 10. By containing the inorganic pigment A having an aspect ratio of 10 or more in the sealing layer, good sealing property due to the flat shape can be obtained. Further, by containing the inorganic pigment B having an aspect ratio of less than 10 in the sealing layer, the adhesion between the sealing layer and the release agent layer provided on the sealing layer is improved.
The aspect ratio is a value obtained by photographing powder particles of an inorganic pigment with an electron microscope and dividing the diameter of 100 randomly extracted particles by the thickness to obtain an average, and the value of the aspect ratio is large. The more flat the inorganic pigment is, the greater the degree of flatness.

As the inorganic pigment A, a pigment having an aspect ratio of 10 or more and generally used for papermaking can be used. Specifically, kaolin, talc, clay, bentonite, saponite, stepnite, montmorillonite and the like can be exemplified, and one or a combination of two or more of these pigments can be used.
Among these, from the viewpoint of obtaining a release paper having excellent flatness and excellent peelability, it is possible to apply the release agent coating liquid uniformly and thinly, and the release agent is cured. In the present invention, it is preferable to use kaolin, which is a flat pigment, from the viewpoint that it needs to be a substance that does not inhibit the above.

As the inorganic pigment B, a pigment having an aspect ratio of less than 10 and generally used for papermaking can be used. Specifically, heavy calcium carbonate, light calcium carbonate, titanium dioxide, aluminum hydroxide, silica and the like can be exemplified, and one or a combination of two or more of these pigments can be used. ..
Among these, heavy calcium carbonate and light calcium carbonate are preferable because the adhesion between the sealing layer and the release agent layer provided on the sealing layer is particularly good.

The volume 50% average particle diameter (D50) measured by the laser diffraction / scattering method of the inorganic pigment B is preferably 0.5 to 2.0 μm.
Here, examples of the laser diffraction / scattering method measuring device include, for example, the particle size distribution measuring device “Partica” manufactured by Horiba, Ltd., and the particle size distribution measuring device “MASTER SIZERS” manufactured by Malvern.

In the pigment component contained in the sealing layer of the present invention, the blending ratio of the inorganic pigment A having an aspect ratio of 10 or more and the inorganic pigment B having an aspect ratio of less than 10 is 95/5 to 50/50 in terms of mass ratio. ..
If the blending ratio of the inorganic pigment A and the inorganic pigment B is less than 95/5 by mass, the adhesion between the sealing layer and the release agent layer provided on the sealing layer becomes insufficient. Further, if the blending ratio of the inorganic pigment A and the inorganic pigment B exceeds 50/50 by mass, the sealing property becomes insufficient.

The blending amount of the synthetic resin latex contained in the adhesive component used for the sealing layer of the present invention is 20 to 50 parts by mass with respect to 100 parts by mass of the pigment component. The blending amount of the synthetic resin latex is preferably 30 parts by mass or more. Further, it is preferably 40 parts by mass or less.
If the blending amount of the synthetic resin latex with respect to 100 parts by mass of the pigment component is less than 20 parts by mass, the sealing property is inferior. On the other hand, if the blending amount of the synthetic resin latex exceeds 50 parts by mass, the release property of the release paper deteriorates, which makes it difficult to use it as recycled paper.

The glass transition temperature (Tg) of the synthetic resin latex is preferably -20 to 30 ° C. If the Tg of the synthetic resin latex is lower than -20 ° C, the coating layer becomes too soft, causing problems such as being easily scratched. Further, when Tg exceeds 30 ° C., the sealing layer tends to be non-uniform, and pinhole defects are likely to occur.
The Tg of the synthetic resin latex is obtained by pretreating the synthetic resin latex at 130 ° C. for 30 minutes, and then using a scanning differential calorimeter (JIS K-7122) for a 10 mg sample under a nitrogen atmosphere at 20 ° C./. The change in specific heat due to the secondary transition in (warm temperature in minutes) is calculated as Tg from the following formula.
(Tg) = Tg1 x α1 + Tg2 x α2 + ... + Tgn x αn
Tg1, Tg2 ... Tgn: Tg (K) of each actually measured composition
α1, α2 ... αn: Mass fraction (%) of each composition alone with respect to the total resin mass

Further, as long as the Tg range of the synthetic resin latex is -20 to 30 ° C., only one type may be used, or two or more types may be used in combination.
The synthetic resin latex used in the present invention includes a styrene / butadiene copolymer, a styrene / acrylic copolymer, an ethylene / vinyl acetate copolymer, a butadiene / methyl methacrylate copolymer, and a vinyl acetate / butyl acetate. Although latexes of various copolymers such as acrylate-based copolymers can be mentioned, in the present invention, it is preferable to use a styrene-budaziene-based copolymer latex having good compatibility with kaolin.

In addition to the synthetic resin latex, a binder such as starch, polyvinyl alcohol, or acrylic resin may be used as an adhesive component as appropriate.

In the present invention, in addition to the pigment component and the adhesive component described above, a dispersant, a water resistant agent, a lubricant, a defoaming agent, a preservative, a dye and the like are appropriately added to the sealing layer. May be good.

In the present invention, the coating method of the sealing layer is not particularly limited, and coating can be performed by a known coating apparatus and coating system. For example, as a coating device, a blade coater, a bar coater, a roll coater, an air knife coater, a reverse roll coater, a curtain coater, a gravure coater, a spray coater, a size press coater, a gate roll coater and the like can be mentioned. Further, as the coating system, water-based coating mainly using water as a medium is preferable.
As a method for drying the sealing layer, for example, a usual method such as a steam heater, a gas heater, an infrared heater, an electric heater, a hot air heater, a microwave, or a cylinder dryer is used.

The coating amount of the sealing layer in the base paper for release paper of the present invention is preferably 8 to 20 g / m ² and more preferably 10 to 15 g / m ² in terms of dry weight.
If the amount of coating of the sealing layer is less than 8 g / m ² by dry weight, it becomes difficult to obtain a uniform sealing layer. Further, when the coating amount of the sealing layer exceeds 20 g / m ² , the improvement in quality with the increase in the coating amount is saturated.

The surface roughness (center line average roughness) of the sealing layer measured based on JIS B 0601: 1994 is preferably 0.5 to 1.0 μm, preferably 0.6 to 0.8 μm. More preferably.
If the surface roughness is less than 0.5 μm, the adhesion between the sealing layer and the release agent layer tends to decrease. Further, when the surface roughness exceeds 1.0 μm, the uniformity of the sealing layer and the coating property of the release agent layer tend to decrease.

The air permeability resistance (Oken type testing machine method) specified in JIS P 8117: 2009 of the base paper for release paper of the present invention is preferably 100,000 seconds or more. When the air permeation resistance is less than 100,000 seconds, the sealing property tends to decrease.

Examples of the release agent that can be used for the base paper for release paper of the present invention include silicone resins, fluorine compounds, aminoalkyd compounds, polyester compounds and the like.
In the present invention, it is particularly preferable to use a silicone resin. Examples of the silicone resin used as the release agent include solvent-free silicone resin, solvent-based silicone resin, aqueous emulsion-based silicone resin, solvent-free UV curable silicone resin, and the like.

In the release paper of the present invention, a release agent is applied on the sealing layer of the base paper for release paper of the present invention so that the coating amount is preferably 0.5 to 2.0 g / m ² by dry weight. Obtained by working.
The method of applying the release agent to the release base paper is not particularly limited, and coating can be performed using a known coating device and coating system. For example, as a coating device, a blade coater, a bar coater, a roll coater, an air knife coater, a reverse roll coater, a curtain coater, a gravure coater, a spray coater, a size press coater, a gate roll coater and the like can be mentioned.
As a method for drying the release agent layer, for example, a usual method such as a steam heater, a gas heater, an infrared heater, an electric heater, a hot air heater, a microwave, or a cylinder dryer is used.

Hereinafter, the present invention will be specifically shown with reference to examples, but the present invention is not limited thereto. Further, unless otherwise specified, parts and% in the examples indicate parts by mass and% by mass, respectively.

(Evaluation method)
<Inorganic pigment>
(1) Volume 50% average particle diameter (D50)
The measurement was performed using a laser diffraction / scattering type particle size distribution measuring device (MASTER SIZER S manufactured by Malvern).
(2) Aspect ratio Measured by the above method.

<Quality evaluation of base paper for release paper>
(1) Air permeation resistance Measured by a method according to JIS P 8117: 2009 (Oken type testing machine method).
(2) Surface Roughness Using a small surface roughness shape measuring machine (SURFCOM 130A manufactured by Tokyo Seimitsu Co., Ltd.), the average roughness of the center line of the sealing layer coated surface (μm) based on JIS B 0601: 1994. Was measured.
(3) Uniformity of Sealing Layer A 10% oil blue toluene solution was prepared as a dyeing solution. This dyeing solution was uniformly applied to the coated surface of the sealing layer, wiped off with gauze after 5 seconds, and then defects (missing pinholes, etc.) of the sealing layer were visually observed and evaluated. If the evaluation is ○ or △, there is no problem in practical use.
[Evaluation criteria]
◯: No defects and uniform sealing Δ: Some defects ×: Many defects

<Quality evaluation of release paper>
(1) Adhesion of Silicone Resin The surface of the release agent layer was rubbed with a finger (load of 5 kg) to evaluate the surface condition. If the evaluation is ○ or △, there is no problem in practical use.
[Evaluation criteria]
◯: No peeling of the release agent layer △: Slight peeling of the release agent layer occurs ×: Peeling of the release agent layer occurs (2) Silicone resin coating property A red marker pen on the surface of the release agent layer A line was drawn with (Teranishi Chemical Industry Co., Ltd., product name: Magic Ink), and after 5 seconds, it was wiped off with gauze, and then the adhesion of the ink was visually observed and evaluated. If the evaluation is ○ or △, there is no problem in practical use.
[Evaluation criteria]
◯: No ink adhered Δ: Slight ink adhered ×: Ink adhered (3) Dissociability Prepare a release paper with an absolute dry weight of 40 g, and the concentration of the release paper is 0.5. The degree of dissociation into water was evaluated when the pulp was immersed in water so as to be% and dissociated with a pulp dissociation tester (manufactured by Kumagai Riki Kogyo Co., Ltd., conforming to JIS P 8220) for 60 minutes. If the evaluation is ○ or △, there is no problem in practical use.
[Evaluation criteria]
◯: Pulp fibers are dispersed and good disintegration property △: Slight pulp fiber binding remains ×: Pulp fiber lumps and pulp fiber binding remaining and poor disintegration property

<Making base paper for release paper>
(Preparation of base paper)
100 parts by weight of hardwood kraft pulp (LBKP) having a Canadian standard filtrate (CSF) of 370 ml was used as the raw material pulp. As a paper strength agent, 0.3 parts by mass of cationized starch was added to 100 parts by mass of the raw material pulp, then 1.5 parts by mass of a sulfuric acid band was added, and then papermaking was performed using a long net multi-cylinder paper machine. A base paper having a basis weight of 120 g / m ² was obtained.

[Example 1]
95 parts by mass of kaolin (manufactured by Imeris, trade name: KCS, aspect ratio: 13, D50: 4.6 μm) as the inorganic pigment A, and light calcium carbonate (aspect ratio: 1, D50: 1.0 μm) as the inorganic pigment B. 5 parts by mass, and 30 parts by mass of styrene / butadiene copolymer latex (manufactured by Japan A & L Co., Ltd., trade name: PA0330, Tg-10 ° C) as an adhesive is blended in an absolute dry state to form a coating liquid for a sealing layer. Was prepared.

Next, using a blade coater, the coating liquid for the sealing layer is applied to one side of the base paper so that the amount of coating is 10 g / m2 in terms of dry weight, and dried to obtain a base paper for release paper. Obtained.

[Example 2]
Same as Example 1 except that 5 parts by mass of heavy calcium carbonate (manufactured by Takehara Chemical Industry Co., Ltd., trade name: Sunlight SL-100, aspect ratio: 1, D50: 6.5 μm) was used as the inorganic pigment B. By the method, a base paper for release paper was obtained.

[Example 3]
80 parts by mass of kaolin (manufactured by Imeris, trade name: KCS, aspect ratio: 13, D50: 4.6 μm) as the inorganic pigment A, and light calcium carbonate (aspect ratio: 1, D50: 1.0 μm) as the inorganic pigment B. A base paper for release paper was obtained by the same method as in Example 1 except that 20 parts by mass was used.

[Example 4]
50 parts by mass of kaolin (manufactured by Imeris, trade name: KCS, aspect ratio: 13, D50: 4.6 μm) as the inorganic pigment A, and light calcium carbonate (aspect ratio: 1, D50: 1.0 μm) as the inorganic pigment B. Was used in an amount of 50 parts by mass, and a base paper for release paper was obtained by the same method as in Example 1.

[Example 5]
For release paper by the same method as in Example 1 except that 20 parts by mass of styrene-butadiene copolymer latex (manufactured by Japan A & L, trade name: PA0330, Tg-10 ° C.) was blended as an adhesive by absolute drying. I got the base paper.

[Example 6]
For release paper by the same method as in Example 1 except that 50 parts by mass of styrene-butadiene copolymer latex (manufactured by Japan A & L, trade name: PA0330, Tg-10 ° C.) was blended as an adhesive by absolute drying. I got the base paper.

[Comparative Example 1]
100 parts by mass of kaolin (manufactured by Imeris, trade name: KCS, aspect ratio: 13, D50: 4.6 μm) was used as the inorganic pigment A, and the same method as in Example 1 was used except that the inorganic pigment B was not used. A base paper for release paper was obtained.

[Comparative Example 2]
40 parts by mass of kaolin (manufactured by Imeris, trade name: KCS, aspect ratio: 13, D50: 4.6 μm) as the inorganic pigment A, and light calcium carbonate (aspect ratio: 1, D50: 1.0 μm) as the inorganic pigment B. Was used in an amount of 60 parts by mass, and a base paper for release paper was obtained by the same method as in Example 1.

[Comparative Example 3]
For release paper by the same method as in Example 1 except that 15 parts by mass of styrene-butadiene copolymer latex (manufactured by Japan A & L, trade name: PA0330, Tg-10 ° C.) was blended as an adhesive by absolute drying. I got the base paper.

[Comparative Example 4]
For release paper by the same method as in Example 1 except that 55 parts by mass of styrene-butadiene copolymer latex (manufactured by Japan A & L, trade name: PA0330, Tg-10 ° C.) was blended as an adhesive by absolute drying. I got the base paper.

The quality evaluation described above was performed on the release paper base papers obtained in Examples 1 to 6 and Comparative Examples 1 to 4. The results are shown in Table 1.

[Example 7]
<Making release paper>
Two parts of a catalyst were added to a solvent-free silicone resin (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: LTC-1053L) to prepare a coating liquid for a release agent.
Next, using an RI printing machine, the above-mentioned release agent coating liquid was applied onto the sealing layer of the release paper base paper of Example 1 so that the amount of application was 1.0 g / m2 in terms of dry weight. After coating, a curing treatment (130 ° C., 10 sec) was performed in a dryer to obtain a release paper.

[Example 8]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Example 2 was used instead of the release paper base paper of Example 1.
[Example 9]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Example 3 was used instead of the release paper base paper of Example 1.
[Example 10]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Example 4 was used instead of the release paper base paper of Example 1.
[Example 11]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Example 5 was used instead of the release paper base paper of Example 1.
[Example 12]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Example 6 was used instead of the release paper base paper of Example 1.

[Comparative Example 5]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Comparative Example 1 was used instead of the release paper base paper of Example 1.
[Comparative Example 6]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Comparative Example 2 was used instead of the release paper base paper of Example 1.
[Comparative Example 7]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Comparative Example 3 was used instead of the release paper base paper of Example 1.
[Comparative Example 8]
A release paper was obtained by the same method as in Example 7 except that the release paper base paper of Comparative Example 4 was used instead of the release paper base paper of Example 1.

The above-mentioned quality evaluation was performed on the release papers obtained in Examples 7 to 12 and Comparative Examples 5 to 8. The results are shown in Table 2.

From the results of Examples 1 to 6 and Comparative Examples 1 to 4, it was confirmed that the base paper for release paper of the present invention had good quality of the sealing layer.
Further, from the results of Examples 7 to 12 and Comparative Examples 5 to 8, it was confirmed that the release paper of the present invention had good adhesion, peelability, and disintegration property.

Claims (12)

A base paper for release paper in which a sealing layer containing at least a pigment component and an adhesive component is provided on at least one surface of the base paper, and the inorganic pigment A and aspect having an aspect ratio of 10 or more as the pigment component. It contains an inorganic pigment B having a ratio of less than 10, the blending ratio of the inorganic pigment A and the inorganic pigment B is 95/5 to 50/50 by mass, and the adhesive component contains at least a synthetic resin latex. A base paper for release paper, wherein the blending amount of the synthetic resin latex with respect to 100 parts by mass of the pigment component is absolutely dry is 20 to 50 parts by mass. The base paper for release paper according to claim 1, wherein the 50% volume average particle diameter (D50) measured by the laser diffraction / scattering method of the inorganic pigment B is 0.5 to 2.0 μm. The base paper for release paper according to claim 1 or 2, wherein the inorganic pigment B is calcium carbonate. The base paper for release paper according to claim 3, wherein the calcium carbonate is light calcium carbonate. The base paper for release paper according to any one of claims 1 to 4, wherein the inorganic pigment A is kaolin. The base paper for release paper according to any one of claims 1 to 5, wherein the glass transition temperature of the synthetic resin latex is -20 to 30 ° C. The base paper for a release paper according to any one of claims 1 to 6, wherein the synthetic resin latex is a styrene-budaziene copolymer latex. The coating amount of the sealing layer obtained from the basis weight difference between the base paper and the base paper for release paper measured based on JIS P 8124: 2011 under the environment of JIS P 8111: 1998 is 8 to 20 g in terms of dry weight. The base paper for release paper according to any one of claims 1 to 7, wherein the content is / m ² . The release according to any one of claims 1 to 8, wherein the surface roughness of the sealing layer surface measured based on JIS B 0601: 1994 is 0.5 to 1.0 μm. Base paper for paper. The release paper according to any one of claims 1 to 9, wherein the air permeation resistance (Oken type testing machine method) specified in JIS P 8117: 2009 is 100,000 seconds or more. Base paper. A release paper having a release agent layer on the sealing layer of the release paper base paper according to any one of claims 1 to 10, and in the environment of JIS P 8111: 1998, according to JIS P 8124: 2011. The release amount of the release agent layer determined from the difference in basis weight between the release paper base paper and the release paper measured based on the above is 0.5 to 2.0 g / m ² in dry weight. paper. The release paper according to claim 11, wherein the release agent layer is a silicone resin layer.