JP2000345497A - Base paper for release paper, release paper, adhesive sheet and production of base paper for release paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a base paper for a release paper for an adhesive sheet excellent in appearance without unevennesses, crinkles, or the like, caused by an adhesive mass layer of an adhesive label applied to an object in the adhesive sheet and further a base paper for the release paper eliminated from the residual paste and improved in operating efficiency in a printing processing step or a labeling step without problems in positional detection at a labeler having a transmitting type positional detector. SOLUTION: At least one surface of a base paper is coated with a coating liquid containing polyvinyl alcohol and dried. The resultant paper is then subjected to threading treatment through a nip part between a metal roll and a metal roll in which the temperature of at least the one metal roll is the glass transition point of the polyvinyl alcohol or above under conditions of 200-3,500 kg/cm linear pressure to produce a base paper for a release paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release paper for a pressure-sensitive adhesive sheet, and more particularly to a release paper for a pressure-sensitive adhesive sheet using a transparent film as a surface substrate. The present invention relates to a pressure-sensitive adhesive sheet release paper having excellent transparency when attached to an adherend. Further, the present invention relates to a release paper having no problem in position detection by a labeler having a transmission type position detector when an adhesive sheet is passed through the labeler, and having no adhesive residue.

[0002]

2. Description of the Related Art A general structure of a pressure-sensitive adhesive sheet comprises a surface substrate, a pressure-sensitive adhesive layer, a release agent layer, and a release sheet.
Paper, film, metal foil, etc. are used as the surface substrate,
The release sheet used is one obtained by applying a release agent such as a silicone compound or a fluorine compound to a release base paper such as high-density paper such as glassine paper, clay-coated paper, or polyethylene laminated paper, or a film obtained by applying a release agent to a film. I have. In addition, solvent-based adhesive, emulsion-type adhesive,
A hot-melt adhesive is used.

[0003] Polyethylene laminated paper or clay coated paper as a release sheet minimizes the penetration of a release agent solution such as a silicone resin into the surface of high quality paper, matte paper, kraft paper or the like made mainly of wood pulp. In order to maximize the performance of the release agent, those having a polyethylene resin film or a clay coat layer formed thereon are generally used. In addition, glassine paper is obtained by making a paper from highly chemically beaten chemical pulp as a raw material and further densifying it with finishing equipment such as a super calender. Further, in order to prevent the penetration of the release agent, a coating composition containing a water-soluble polymer as a main component is applied to base paper. As a method of coating on glassine paper, it is manufactured by a scraping method such as blade coating and a roll coater method such as size press or gate roll.

[0004] Japanese Patent No. 2,886,336 discloses a highly smoothed glassine paper comprising two or more metal rolls, wherein at least one metal roll has a surface temperature of 80 to 2 mm.
100 kg / cm in the nip heated to 00 ° C
A method for producing glassine paper in which a sheet is drawn under the above-mentioned pressurized conditions and subjected to a high smoothing treatment is described. Examples include:
Surface smoothness of 3500s under 200kg / cm pressure
ec, there is an example in which the smoothness of the back surface is 1500 seconds. This glassine paper is based on the premise that the pulp is beaten to a CSF of 200 ml. However, beating the CSF20
By proceeding to 0 ml, not only the dimensional stability is degraded and the paper stiffness tends to deteriorate, but also extra power is required to advance the beating, which is economically disadvantageous.

Japanese Patent Application Laid-Open No. Hei 5-247896 describes that a base paper is coated with a mixed solution mainly composed of polyvinyl alcohol, starch and filler, and a super calender is applied as a pressure treatment. I have. However, it is difficult to obtain transparency as high as that of glassine paper because the beating is not advanced by super calendaring.

Furthermore, the suppression of penetration of the release agent and the covering (coverability) of the paper surface with the release agent were insufficient. When the pressure-sensitive adhesive is applied to the release paper composed of the paper surface and the release agent layer in such a state, the pressure-sensitive adhesive enters pinholes and recesses of the release agent layer. When the pressure-sensitive adhesive sheet is finished in that state, and then the surface substrate to which the pressure-sensitive adhesive is adhered is peeled from the release agent layer, a phenomenon that the pressure-sensitive adhesive remains on the release paper (hereinafter referred to as adhesive residue) is observed.

[0007] This adhesive residue phenomenon occurs when the adhesive sheet adheres to a guide roll or the like that comes into contact with the surface of the release agent layer during printing, die cutting (punching), desalting, etc. in the process of subjecting the adhesive sheet to form printing or seal printing. This causes troubles such as poor paper feed and printing misalignment, which is an extremely serious obstacle to workability and quality. Also, in the step of printing or labeling with an auto-labeler, a handler labeler, or the like, similarly, adhesive residue on the surface of the release agent layer such as a paper feeding failure or a print deviation becomes a problem. To remedy this problem, it is important to further improve the barrier properties of the paper.

In the present invention, when a film is used as the surface base material of the pressure-sensitive adhesive sheet and a paper base material is used as the release sheet, when the pressure-sensitive adhesive is transparent, a pattern such as unevenness or undulation of the release sheet is formed on the pressure-sensitive adhesive layer. The transferred and pasted film surface looks wavy or undulate. As described above, when a paper base is used for the release sheet, the appearance is impaired, and thus, a bad image may be given to the attached one. In order to solve this, a release agent is applied on a film substrate and used as a release sheet. However, unlike the surface base material, the release sheet is peeled off at the time of sticking and is discarded. At that time, disposal is done by incineration or landfill as waste. Waste containing film has a high temperature at the incineration temperature due to incineration, and includes many problems such as durability problems of incinerators, pollution problems such as incineration gas, lack of landfill sites, and effects on the natural environment. .

[0009]

SUMMARY OF THE INVENTION The present invention provides a release paper base paper for an adhesive sheet having an excellent appearance without irregularities or undulations caused by an adhesive layer of an adhesive label attached to an object in an adhesive sheet. Is what you do. Further, the present invention relates to a base paper for release paper, which has no problem in position detection by a labeler having a transmission type position detector, eliminates adhesive residue, and improves workability in printing and labeling processes.

[0010]

According to the present invention, the temperature of at least one metal roll is equal to or higher than the glass transition point of the polyvinyl alcohol after applying and drying a coating solution containing polyvinyl alcohol on at least one surface of the base paper. A linear pressure of 200 to 350 is applied to the nip between the metal roll and the metal roll.
A base paper for release paper, which has been subjected to a paper passing process under a condition of 0 kg / cm.

The present invention relates to a release paper in which the smoothness of the coated surface after the paper passing process is 2000 seconds or more according to the Oken method. The present invention relates to a base paper for release paper in which the coating amount of polyvinyl alcohol is 0.4 to 1.6 g / m ² per side as a solid content. The present invention relates to a base paper for release paper in which polyvinyl alcohol and kaolin are contained in a coating liquid. The present invention relates to a base paper for release paper that has been subjected to a paper passing process at a linear pressure of 200 to 350 kg / cm. In the present invention, kaolin pigment 100
25 to 400 parts by weight of polyvinyl alcohol
It relates to a base paper for release paper containing parts by weight. The present invention relates to a base paper for release paper having an air permeability of 5000 seconds or more. The present invention relates to a release paper in which a release agent is applied to a polyvinyl alcohol-coated surface of a release paper base paper. The present invention relates to a release paper in which the release agent is a solventless silicone. The present invention relates to a release paper in which the smoothness of the release agent-coated surface is 1000 seconds or more according to the Oken method. The present invention relates to a pressure-sensitive adhesive sheet in which a surface substrate, a pressure-sensitive adhesive layer, and a release paper are sequentially laminated, and the above-described release paper is used as the release paper. The present invention
The present invention relates to an adhesive sheet whose surface substrate is a film.

According to the present invention, a coating liquid containing polyvinyl alcohol is coated on at least one side of a base paper with a coating machine of a blade coater system and dried, and then the temperature of at least one metal roll is equal to or higher than the glass transition point of the polyvinyl alcohol. The linear pressure is 2 at the nip between the metal roll
A method for producing a base paper for release paper, wherein a paper passing process is performed under a condition of 00 to 3500 kg / cm.

According to the present invention, at least one side of a base paper is coated with a coating solution containing polyvinyl alcohol and kaolin pigment with a roll coater type coating machine, dried, and then dried at least.
Release paper characterized in that a paper roll is passed through a nip portion between one metal roll and a metal roll whose temperature is equal to or higher than the glass transition point of the polyvinyl alcohol at a linear pressure of 200 to 350 kg / cm. This is a method for producing base paper.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have studied a pressure-sensitive adhesive sheet having a surface substrate and a release sheet, particularly when a film is used as the surface substrate and a paper substrate is used as the release sheet. We have been studying the surface irregularities of the base film. In addition, studies have been made on a method of improving the barrier property for improving the adhesive residue.
As a result, as a factor of the surface unevenness phenomenon of the surface base film, the smoothness of the surface of the used release paper and the partial thickness and thickness of the release paper greatly contribute, and also suppress the penetration of the release agent. It has been found that this can be improved by adding a kaolin pigment to the surface coating layer, and the present invention has been completed.

The base paper for release paper of the present invention is obtained by providing a layer containing polyvinyl alcohol on a base paper by using a coating machine of a blade coater system, and then forming at least one nip portion between a metal roll and a metal roll. The metal roll temperature is set to be equal to or higher than the glass transition point (hereinafter referred to as Tg) of polyvinyl alcohol in the coating liquid, and the nip linear pressure is set to 200 to 3500 k.
It is characterized in that the paper passing process is performed at g / cm. Furthermore, after providing a layer containing polyvinyl alcohol and kaolin pigment by a roll coater type coating machine, at least one metal roll is heated to a nip portion composed of a metal roll and a metal roll at a temperature of at least Tg of polyvinyl alcohol in the coating liquid. And the paper passing process is performed at a nip linear pressure of 200 to 350 kg / cm.

Polyvinyl alcohol is preferable because it exhibits excellent barrier properties when it is formed into a film and prevents the release agent from penetrating into the substrate when forming a release agent layer in a later step. Further, the film has an appropriate hardness, and particularly, the surface of the metal roll has a T
g or more, and when the metal roll is subjected to high pressure treatment with a metal roll, the surface of the metal roll is transferred to the polyvinyl alcohol surface, and a highly smooth surface which cannot be normally obtained only by coating is obtained. This is because the base paper itself is flattened and thinned by the high-pressure treatment, the surface is smoothed, and a smoother surface is obtained in addition to the smoothing of the polyvinyl alcohol layer. Therefore, the desired effect of the present invention cannot be obtained in the step of applying polyvinyl alcohol after the high-pressure treatment.

The base paper of the present invention has an Oken-type smoothness of 200
The time is adjusted to 0 seconds or more, more preferably 4000 seconds or more, and still more preferably 8000 seconds or more. In the case of less than 2,000 seconds, the smoothness is slightly inferior, so that the pattern of the unevenness or undulation of the release paper is easily transferred to the adhesive layer, and the surface of the film attached to the object to be attached appears wavy. Or a swelling tendency appears. Similarly, the Oken type smoothness after coating the release base paper with the release agent is 1000 seconds or more, more preferably 3000 seconds or more. The reason for this is that the smoothness changes up and down by the steps of applying a release agent, drying and curing, and is generally about 1000 seconds or more. This is because the surface tends to be rough and the smoothness tends to be low.

The base paper of the release paper of the present invention has an Oken type air permeability of 50.
It is preferably at least 00 seconds. More preferably, it is adjusted to 10,000 seconds or more. If the time is less than 5000 seconds, the barrier property tends to be slightly inferior, and the adhesive residue tends to be slightly inferior.

As a method of obtaining a highly smooth polyvinyl alcohol film, there is a method of performing a melt lamination with a melt-processed type polyvinyl alcohol. This is a method in which a molten resin is extruded onto a paper base material, and then a high-smooth surface is obtained by a cooling roll. However, the thickness of the molten resin is limited to about 10 μm due to a problem such as a pinhole. This is about 10 g / m ² . Thinner coatings are technically difficult.

Further, there is a release paper obtained by melt-extruding a thermoplastic resin, for example, a polyethylene resin on the glassine paper as described above, and the release paper has a smoothness of several thousand seconds. However, such release paper still has a strong surface undulation caused by the release paper when a pressure-sensitive adhesive sheet is formed using a transparent film as a surface base material. The undulation caused by the paper affects the transparent film as the surface substrate.

Normally, when only one surface of a paper substrate is coated with polyvinyl alcohol, a large curl occurs on the polyvinyl alcohol side. However, after the polyvinyl alcohol is coated, a high pressure treatment is performed in a nip portion composed of a metal roll and a metal roll. Curling is reduced.

The blade coater method used in the present invention is a method in which a large amount of a coating liquid is once brought into direct contact with a blade or a rod to scrape the coating liquid and to measure and smooth the coating liquid. This has a remarkable effect on the pinhole barrier property.

A base paper coated by a transfer or printing type coating machine such as a roll size press method or a roll coater method can be used for forming a pinhole or the like even if the coating amount of a coating mainly containing polyvinyl alcohol is increased. Defects remain, and when the pressure-sensitive adhesive layer is formed after the release agent layer is provided, a slight thickness of the pressure-sensitive adhesive layer remains, so that a pattern such as undulation can be seen on the surface of the attached film. In these types of coating, defects such as pinholes are considered to remain due to the penetration of the layer coating liquid containing polyvinyl alcohol as a main component into the base paper due to the nip pressure of the roll and the coating pattern at the time of transfer.
However, although the reason is not clear, if the polyvinyl alcohol coating layer contains a kaolin pigment, it is coated with a roll coater type coating machine, and in a later step the metal roll temperature is equal to or higher than the polyvinyl alcohol Tg. When pressure treatment is performed by passing the paper through the nip part consisting of, the surface is smoothed and the coating layer is pushed into the gap between the paper fibers, resulting in increased barrier properties and transparency of the release paper base paper, and suitability for a transmission type position detector Is considered to be secured.

The polyvinyl alcohol used in the present invention can be used by appropriately selecting the degree of saponification and the degree of polymerization. For example, various modified polyvinyl alcohols such as carboxy-modified, acetoacetyl-modified, and silicon-modified can also be used effectively. In addition, various auxiliaries can be used as needed as long as the object of the present invention is not impaired. For example, lubricants such as liquid paraffin, natural paraffin, microwax, hydrocarbons such as polyethylene wax, fatty acids such as stearic acid, lauric acid, stearamide, palmitic amide, methylenebisstearamide, Fatty acid amides such as ethylene bissteroamide, butyl stearate, hydrogenated castor oil, and esters such as ethylene glycol monostearate;
Examples thereof include alcohol-based products such as cetyl alcohol and stearyl alcohol, and metal soap-based products such as lead stearate, zinc stearate, and calcium stearate.

Examples of inorganic pigments include kaolin, talc, clay, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine anhydrous silica, activated clay, zinc oxide, aluminum oxide, aluminum hydroxide, zinc sulfate, barium sulfate, Examples include silicon dioxide and colloidal silica. Among them, kaolin is particularly preferred.

The particle size of kaolin used in the present invention is as follows:
For example, it is measured by a Sedigraph 5100 manufactured by Shimadzu Corporation. The average particle size of kaolin is preferably 5 μm or less.

Further, curing agents such as glyoxal, methylol melamine, potassium persulfate, ammonium persulfate, sodium persulfate, ferric chloride, chloride, boric acid and ammonium chloride, sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, lauryl alcohol Surfactants such as sulfates / sodium salts, alginates, fatty acid metal salts, etc., as well as various types of adhesives, cross-linking agents, water-proofing agents, oil-proofing agents, clarifying agents, coloring agents, defoamers, release agents, etc. Auxiliaries can be added as appropriate. Also, two or more auxiliary agents can be used in combination.

In the present invention, coating is performed on base paper using a blade coater type or roll type coating machine. Coating amount is 0.4 per side as solid content of polyvinyl alcohol.
To 1.6 g / m ² , more preferably 0.5 to 1.0 g / m ²
and m ^2. If it is less than 0.4 g / m ² , the pinhole barrier property is not sufficient, and the application of the release agent is undesirably increased. On the other hand, a large amount of coating exceeding 1.6 g / m ² is not preferable because it imposes a burden on economy and coating suitability.

As the blade coater type coating machine of the present invention, for example, a trailing blade, a flooded nip blade, a fountain blade, a short dowel blade, a differential building blade, a bellvapa blade and the like are used. Particularly, a short dowel blade is preferable. It is also possible to use rods for the blade holders of these coaters. As the roll type coating machine of the present invention, a forward rotation roll coater, a reverse roll coater, a gate roll coater, or the like is used. Further, whether the coater is installed on-machine or off-machine is optimally selected depending on the manufacturing process and the type of manufacturing in the factory. On-machine is preferable because efficiency of the process and comprehensive management of quality can be achieved.

The base paper used in the present invention is wood pulp,
Alternatively, the material is not particularly limited as long as it is a substrate using non-wood pulp, and generally known high quality paper, medium quality paper, paperboard and the like can be used. As wood pulp, for example, chemical pulp such as commonly used softwood bleached kraft pulp (hereinafter NBKP) and hardwood bleached kraft pulp (hereinafter LBKP), GP,
Examples include mechanical pulp such as BCTMP and MP. Non-wood pulp includes kenaf, cotton and the like. Also, D
Pulp such as IP can also be used.

The binder, the internal sizing agent and the external sizing agent can be used without particular limitation as long as the effects of the present invention are not impaired. Examples of the binder include starches such as oxidized starch, enzyme-modified starch, cation-modified starch, ester starch, ether starch, methylcellulose, ethylcellulose, carboxymethylcellulose, methoxycellulose, hydroxycellulose, completely (or partially) saponified polyvinyl alcohol, and carboxy-modified. Polyvinyl alcohol such as polyvinyl alcohol and silicon-modified polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / methacrylate copolymer, styrene / maleic anhydride copolymer Combined alkali salt, alkali salt of isobutylene / maleic anhydride copolymer, water-soluble polymer such as casein, polyvinyl acetate, polyurethane, polyacrylic acid, polya Acrylic acid ester, polymethyl methacrylate, styrene-butadiene copolymer, latexes such as vinyl chloride-vinyl acetate copolymer a styrene-butadiene-acrylic copolymers. As the sizing agent, a rosin-based sizing agent, alkenyl succinic anhydride, or the like can be appropriately used.

Organic and inorganic fillers can be used at the time of internal addition as long as the effects of the present invention are not impaired. For example, kaolin, talc, clay, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine anhydrous silica,
Activated clay, zinc oxide, aluminum oxide, aluminum hydroxide, zinc sulfate, barium sulfate, silicon dioxide, inorganic pigments such as colloidal silica, and organic pigments such as urea formalin resin filler, nylon powder and polyethylene powder.

The papermaking method used in the present invention is not particularly limited, but includes a fourdrinier multi-cylinder paper machine, a fourdrinier Yankee paper machine,
A round mesh paper machine or the like can be used.

The nip linear pressure of the pressurizing condition when high-pressure treatment is performed in the nip portion composed of a metal roll and a metal roll is 200 to 3500 k when the coating liquid is applied by a blade coater method.
g / cm is preferred. By the way, if it is less than 200 kg / cm, the desired effect is unlikely to appear and 3500 kg / cm
If it exceeds, a phenomenon occurs in which only a part is stretched, and a uniform base material cannot be obtained, and the commercial value is lost. Further, the nip linear pressure when the coating liquid containing the kaolin pigment is applied by a roll coater method is more preferably 200 to 350 kg / cm. There may be a plurality of nip portions composed of a metal roll and a metal roll.

The temperature of the metal roll treated in the present invention is preferably not lower than Tg of polyvinyl alcohol in the coating liquid. The Tg of polyvinyl alcohol is about 60 to 80C, and the temperature at which the smoothness of the metal roll surface is transferred to the polyvinyl alcohol surface is preferably 60C or more. Specifically, 60 ° C to 300 ° C is preferable. Roll temperature is 60
When the temperature is lower than ℃, the polyvinyl alcohol layer is not transferred onto the surface of the metal roll, and it is difficult to obtain a highly smooth surface. The optimum temperature range of the roll temperature depends on the paper passing speed.
Since the amount of heat transferred to the paper changes, blisters may occur even at a temperature of 300 ° C. or less if the paper passing speed is slow. However, generally above 300 ° C,
Moisture in the paper becomes a gas at a stretch, and the volume of the paper rapidly expands, causing a part of the paper to partially peel off, causing a blister phenomenon in which the surface expands, and a uniform paper substrate cannot be obtained.

In the present invention, the surface in which at least one metal roll having a temperature equal to or higher than the Tg of polyvinyl alcohol is in contact with the release base paper is most preferably a surface coated with polyvinyl alcohol. If the coated surface is equal to or higher than Tg, a desired effect can be obtained even if the surface is opposite to the coated surface.

A release agent may be applied in advance to the surface of a metal roll which is to be coated with polyvinyl alcohol at a level that does not affect the release agent coating in the next step or the quality of release paper after coating. . This is an effective method for preventing the polyvinyl alcohol on the coating surface from being softened by heat and transferring to the metal roll surface.

The paper passing speed in the present invention has a large relation with the temperature as described above, and cannot be determined strictly.
500 m / min is desirable. By the way, if it exceeds 500 m / min, the temperature and pressure transmitted to the paper are not enough, and it is difficult to obtain the desired effect.

The water content of the paper at the time of pressurization is preferably 2 to 15%, more preferably in the range of 5 to 10%. By the way, if it is less than 2%, the entanglement of the fiber and the fiber is poor, and the effect cannot be obtained. Absent. With the water content in the above range, the higher the water content, the higher the effect of compressing the paper substrate.

When the roll temperature during the high-pressure treatment is high,
Since the temperature of the paper base has also risen, it is preferable to cool the paper base that has been subjected to high-pressure treatment with a cooling roll or the like after pressurization in order to lower the temperature of the paper base.

Examples of the release agent include a thermosetting silicone compound, a UV curing silicone compound, and an EB curing silicone compound. The form can be appropriately selected from a solvent type, an emulsion type, and a non-solvent type. The release paper of the present invention is particularly suitable for a solventless type because of its high smoothness. As a method of performing solventless coating, a multi-stage roll coater, a gravure coater, or the like is used. The amount of coating in this case is 0.
About 5 to 1.5 g / m ² , more preferably 0.5 to 1.
It is appropriately adjusted within a range of about 0 g / m ² . When the coating amount is less than 0.5 g / m ² , the effect as a release agent layer is inferior. On the other hand, when the coating amount exceeds 1.5 g / m ² , it is not economically practical.

When the release paper of the present invention is used for a pressure-sensitive adhesive sheet using a transparent film as a surface substrate, curl is likely to occur due to the humidity of the outside air after the final product pressure-sensitive adhesive sheet is prepared. This is because although the surface substrate is a film, there is no ingress or egress of moisture and the dimensions do not change, but since the release paper is a paper substrate, its dimensions change due to the ingress and egress of moisture. Therefore, it is common to provide a layer such as a moisture-proof layer on the back surface of the release paper. The treatment for providing a layer such as a moisture-proof layer is preferably performed after high-pressure treatment by a nip composed of a metal roll and a metal roll. The reason is that if a polyvinyl alcohol layer is provided on the surface and a moisture-proof layer is provided on the back, moisture in the paper base material cannot escape during the high-pressure treatment, and blisters are easily generated.

In the present invention, paper is used as the base material of the release sheet without using a film. Therefore, when the release paper after use is discarded, there are problems such as incineration and influence on the natural environment. Can be reduced.

Examples of the adhesive include natural rubber, styrene-butadiene copolymer latex, styrene-isoprene block copolymer, recycled rubber, synthetic rubber and other rubber-based, acrylic and silicone-based adhesives. . These pressure-sensitive adhesives are applied in the form of a solvent system, an aqueous emulsion system, a hot melt system, a liquid curing type or the like, for example, by a knife coater, a roll coater, a die coater, a gravure coater, screen printing, or the like. The coating amount in this case is about 7 to 40 g / m ² by dry weight, preferably 10
It is adjusted in the range of about 30 g / m ² . In addition, 7 g /
If it is less than m ² , the effect as an adhesive layer is poor, and
A coating amount exceeding g / m ² saturates the effect and is not preferable from an economical viewpoint.

[0045]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. Unless otherwise specified, parts and% in the examples indicate “parts by weight” and “% by weight”, respectively, and the coating amount, the number of parts, the mixing ratio, and the like are all indicated by solid content.

Example 1 To a pulp slurry of 100 parts of LBKP having a freeness of 450 ml, a rosin size (trade name “Size Pine E”, manufactured by Arakawa Chemical Industry Co., Ltd.) as a sizing agent was added in an amount of 0.4% based on the dry pulp. After adding a sulfuric acid band to the pulp slurry and fixing it, papermaking was carried out with a fourdrinier paper machine, and an aqueous solution of oxidized starch (trade name "Ace A", manufactured by Oji Cons) was 2.0 g / m2 in solid content on both sides. ² so as to be size-press coating in a two-roll size press basis weight 80 g / m
² base paper was obtained.

An aqueous solution of polyvinyl alcohol (trade name “PVA117” manufactured by Kuraray Co., Ltd.) was applied to the release agent coating surface of the base paper by an off-machine short dowel coater to a dry coating amount of 1.0 g / m ^2. After processing, remove paper moisture by 6
%, And a metal roll temperature of 120 ° C. and a linear pressure of 1000 kg / c
m and a paper passing speed of 20 m / min to obtain a base paper for release paper.

Example 2 In Example 1, polyvinyl alcohol (trade name “P
VA117 "(manufactured by Kuraray Co., Ltd.) in an amount of 0.
A base paper for release paper was obtained in the same manner as in Example 1 except that the amount was 6 g / m ² .

Example 3 An aqueous solution of polyvinyl alcohol (trade name: PVA-117, manufactured by Kuraray Co., Ltd.) was applied to the surface of the base paper made in Example 1 in a dry coating amount by an off-machine short dwell coater on a surface for applying a release agent. 0.0 g / m ^{2 was} applied to adjust the paper moisture to 6%. This base paper is subjected to a metal roll temperature of 150 ° C. and a linear pressure of 250.
The paper was passed under the conditions of kg / cm and a paper passing speed of 100 m / min to obtain a release paper. Thereafter, a base paper for release paper was obtained in the same steps as in Example 1.

Example 4 In Example 1, the metal roll temperature was 100 ° C. and the linear pressure was 250.
A base paper for release paper was obtained in the same steps as in Example 1, except that the paper passing speed was set to 0 kg / cm and the paper passing speed was set to 50 m / min.

Example 5 Alkenyl succinic acid (trade name "Size Pine SPS-300", Arakawa Chemical Industries, Ltd.) and amphoteric acrylamide (trade name "Polystron") were added to a pulp slurry having 25 parts of NBKP and 75 parts of LBKP each having a freeness of 400 ml. KW-831HC, manufactured by Arakawa Chemical Industry Co., Ltd.) were added at 0.06% and 0.7%, respectively. After adding and fixing 1.2% of a sulfuric acid band to this pulp slurry, papermaking is carried out with a fourdrinier paper machine, and polyvinyl alcohol (trade name "Gohsenol GH-20", manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) with an on-machine gate roll coater. 1 part of 67 parts of kaolin pigment (trade name "HT clay", manufactured by Engelhardt) for 100 parts
A 3.6% mixed solution was applied on one side at 2.0 g / m ² (1.2 g / m ^{2 in} terms of polyvinyl alcohol) to obtain a base paper.
The obtained base paper had a rice area of 71 g / m ² , a paper thickness of 85 μm, and a water content of 6.5%. The obtained base paper was passed through a nip portion composed of a metal roll and a metal roll under the conditions of a metal roll temperature of 120 ° C., a linear pressure of 250 kg / cm, and a paper passing speed of 200 m / min to obtain a base paper for release paper.

Example 6 A solvent-free silicone release agent (product name "KNS3004A" was added to 50 parts of the product name "KNS3004" for the base paper for release paper of Example 5).
The mixture (Shin-Etsu Chemical Co., Ltd.) added with 50 parts of "B" was coated with an offset gravure coater at 1.0 g / m ² and dried with hot air to obtain a release paper.

Comparative Example 1 Commercially available glassine paper of 80 g / m ² per square meter was used as base paper for release paper, and a solvent type silicone release agent trade name “SD73” was used.
33 "a to 100 parts, trade name" SRX-212 "and manufactured by 0.6 parts of added mixture Toray Dow Corning Co., Ltd.) with a bar coater, 0.9 g / m ² was applied, and dried with hot air cured peeling I got the paper.

Comparative Example 2 A commercially available paper prepared by melt-laminating a 16 μm polyethylene resin on a glassine paper of 80 g / m ² was used as a comparative example.
0.45 g / m ^{2 of} the release agent used in 1 was applied to obtain a release paper.

Comparative Example 3 Commercially available kraft paper of 85 g / m ² of rice tsubo was melt-laminated with 16 μm polyethylene resin, and the release agent used in Comparative Example 1 was applied at 0.50 g / m ^2. Release paper was obtained.

Comparative Example 4 The paper made in Example 1 was subjected to a metal temperature of 55 ° C. and a linear pressure of 10 at a nip portion composed of a metal roll and a metal roll.
The paper was passed under the conditions of 00 kg / cm and a paper passing speed of 20 m / min. Thereafter, 1.0 g of an aqueous solution of polyvinyl alcohol (trade name: PVA-117, manufactured by Kuraray Co., Ltd.) was applied to the release agent coating surface of the base paper using an off-machine short dwell coater.
/ M ² to obtain a base paper for release paper.

Comparative Example 5 In Example 1, the metal roll temperature was 120 ° C. and the linear pressure was 100.
A base paper for release paper was obtained in the same steps as in Example 1 except that the weight was changed to kg / cm.

Comparative Example 6 The paper made and coated in Example 1 was heated to a metal roll temperature of 120.
The paper was passed under the conditions of ° C and a linear pressure of 4000 kg / cm. A phenomenon in which only a part of the paper was stretched after paper passing occurred, and a uniform base material could not be obtained.

Comparative Example 7 The base paper made in Example 5 was super-calendered using a multi-stage calender comprising a metal roll and an elastic roll to obtain a base paper for release paper. At this time, the temperature of the metal roll gradually increased from 80 ° C. at the uppermost stage to the lower stage, and was 130 ° C. at the lowermost stage.
kg / cm.

The solvent-based silicone release agent (trade name “SD73”) was used for the base paper for release paper of Examples 1 to 5 and Comparative Examples 4, 5 and 7.
33 "a to 100 parts, trade name" SRX-212 "and manufactured by 0.6 parts of added mixture Toray Dow Corning Co., Ltd.) with a bar coater, 0.85 g / m ² was applied, and dried with hot air cured peeling I got the paper.

When the surface substrate is a film and the appearance (irregularities and undulations) of the pressure-sensitive adhesive sheet is evaluated, a solvent-type pressure-sensitive adhesive (trade name “BPS-5569”) is applied to each of the obtained release papers.
(Toyo Ink Co., Ltd.) was applied at 22 g / m ² with a comma coater, dried, and then 38 μm of PET was attached and evaluated with an adhesive sheet.

In order to evaluate whether or not the obtained release paper base paper can be detected by the transmission position detector, an emulsion-type adhesive (trade name “Cybinol SVP”) is applied to each release paper obtained.
101 "(manufactured by Seiden Chemical Co., Ltd.) using a reverse roll coater so as to have a dry weight of 20 g / m ^2, and after drying, high-quality paper having a basis weight of 64 g / m ² was attached and evaluated with an adhesive sheet. .

[Evaluation] (Smoothness) Measured with an Oken type smoothness meter.

(Air permeability) Measured by an Oken type air permeability meter.

(Appearance) The state of the pressure-sensitive adhesive sheet was visually judged from the surface substrate. Evaluation criteria ：: Degrees in which surface irregularities are faint. '': A level at which there is no problem in practical use, although surface irregularities can be confirmed. X: The level at which the unevenness of the surface is considerably deep, which is a problem in practical use.

(Evaluation of Glass Adhesion) The release paper was peeled off from the pressure-sensitive adhesive paper sheet and adhered to the glass surface, and was visually judged from the surface substrate. Evaluation criteria ：: The degree to which the unevenness of the pressure-sensitive adhesive is slightly recognized. '': Irregularities of the pressure-sensitive adhesive can be confirmed, but there is no practical problem. Δ: The level at which the unevenness of the pressure-sensitive adhesive remains can be confirmed, which is a problem in practical use. X: The level at which the unevenness of the adhesive is considerably deep, which is a problem in practical use.

(Glue residue) The obtained pressure-sensitive adhesive sheet was printed by a seal printing machine, die-cut (punched), and desalted, and the degree of adhesion of the pressure-sensitive adhesive to a guide roll hitting the release layer surface was visually determined. Evaluation criteria ：: Adhesion of glue to the guide roll was not observed at all. B: Adhesion to the guide roll is slightly observed. X: Adhesion to the guide roll is often observed.

(Appropriateness of Phototube) The adhesive label finished as a label was checked with an autolabeler whether the phototube of the paper feed detector could detect light and whether the label could be detected. Evaluation criteria ：: Detection with a phototube is possible. X: Detection with a phototube is impossible.

[0069]

[Table 1]

[0070]

As can be seen from Examples 1 and 3 in Table 1, when a high pressure treatment is performed when a film pressure-sensitive adhesive sheet is prepared, if the smoothness is high, irregularities appearing on the surface substrate are reduced. Further, from Comparative Example 4 and Example 1, it was found that when the metal temperature roll was lower than the Tg of polyvinyl alcohol, the appearance was not improved even if the linear pressure was high. Further, it was found that the effect could not be obtained unless the metal roll temperature was higher than Tg and the linear pressure was not within a certain range. From these results, it was possible to obtain a film pressure-sensitive adhesive sheet excellent in appearance such as unevenness and undulation caused by the release paper of the label. Also,
Since a film is not used for the release sheet, problems such as incineration of the used release paper when discarded and the effect on the natural environment can be reduced.

Claims (14)

[Claims] (1) After applying a coating liquid containing polyvinyl alcohol on at least one side of a base paper and drying the coating liquid,
A paper roll having a metal roll having a temperature equal to or higher than the glass transition point of the polyvinyl alcohol and a nip portion between the metal rolls and having a linear pressure of 200 to 3500 kg / cm. Base paper. 2. The smoothness of the coated surface after the paper passing process is 2
2. The base paper for release paper according to claim 1, wherein the base paper has a duration of at least 2,000 seconds. 3. The coating amount of polyvinyl alcohol is 0.4 to 1.6 g / m ² per one side as a solid content.
Or base paper for release paper according to 2. 4. The base paper for release paper according to claim 1, wherein a kaolin pigment is further contained in the coating liquid. 5. The base paper for release paper according to claim 4, wherein the linear pressure is 200 to 350 kg / cm. 6. The base paper for release paper according to claim 4, wherein 25 to 400 parts by weight of polyvinyl alcohol is contained based on 100 parts by weight of the kaolin pigment. 7. The method according to claim 1, wherein the air permeability is 5000 seconds or more.
6. A base paper for release paper according to 6. 8. A release paper, characterized in that a release agent is applied to the surface of the base paper for release paper according to claim 1 coated with polyvinyl alcohol. 9. The release paper according to claim 8, wherein the release agent is a solventless silicone. 10. The smoothness of the surface coated with a release agent is 100 according to Oken's formula.
The release paper according to claim 8 or 9, wherein the time is 0 second or more. 11. A pressure-sensitive adhesive sheet in which a surface substrate, a pressure-sensitive adhesive layer and a release paper are sequentially laminated, wherein the release paper according to claim 8 is used as said release paper. 12. The pressure-sensitive adhesive sheet according to claim 11, wherein the surface substrate is a film. 13. A coating solution containing polyvinyl alcohol is applied to at least one side of a base paper by a coating machine of a blade coater system and dried, and then the temperature of at least one metal roll is equal to or higher than the glass transition point of the polyvinyl alcohol. A linear pressure of 200 to 3 is applied to the nip between metal rolls and metal rolls.
A method for producing base paper for release paper, wherein the paper is passed under a condition of 500 kg / cm. 14. A coating solution containing polyvinyl alcohol and kaolin pigment is applied to at least one side of a base paper by a coater of a roll coater system and dried, and the temperature of at least one metal roll is set to the glass transition point of the polyvinyl alcohol. A method for producing a base paper for release paper, wherein the metal roll and the nip between the metal rolls are subjected to a paper passing process under a linear pressure of 200 to 350 kg / cm.