JP2001073298A - Method and apparatus for producing release paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain a release paper favorably comparable with a conventional release paper by installing a releasing agent coater through a cooler in an online process of a calender apparatus. SOLUTION: A base paper for a release paper is sent from a feed roller 1 through plural guide rollers 5 to a nip part which is composed of at least a pair of metal rolls 2 and in which the temperature of at least one metal roll 2 is 100-300 deg.C, calendered under 100-3,500 kg/cm, preferably 200-1,200 kg/cm pressure, guided through a cooling process composed of cooling rollers 3 to a releasing agent coater 4 directly connected to the cooling process, coated with a coating solution containing a releasing agent in an online process and sent out to a drying part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing an adhesive release paper, and more particularly to a method and an apparatus for efficiently producing a release paper.

2. Description of the Related Art Release paper is obtained by applying release treatment agents having various release performances to base paper for release paper. Adhesive release paper has become an indispensable component of adhesive products using pressure-sensitive adhesives such as seals, labels, and adhesive tapes. Process release paper is used as a carrier paper in the production process of films, sheets, synthetic leather, decorative boards and the like.

[0002] As base paper for release paper, paper such as glassine paper, clay-coated paper, super calender paper, and poly-laminate paper is used, and in addition to paper, plastic films, metal foils and the like may be used. Usually, a polyolefin resin is melt-laminated or coated or impregnated with an aqueous coating composition such as polyvinyl alcohol so that the release agent does not soak into the paper when the release agent is applied to the base paper for release paper. ing. Examples of the release agent include a silicone resin, a fluorine resin, an amino alkyd resin, a polyester resin and the like, and an emulsion, a solvent type or a non-solvent type is used. Generally, silicone resin is most often used, for example, solvent-based silicone and solvent-free silicone are used. In recent years, there has been a strong demand for consideration of safety and pollution, and it has been strongly desired to stop using solvents, particularly from the viewpoint of maintaining the health of workers, and solventless silicones are increasing.

[0003] An adhesive sheet using such a release paper includes an adhesive sheet. The adhesive sheet is usually composed of a surface substrate, an adhesive layer and a release paper. Paper, film, metal foil, etc. are used for the surface substrate, and the adhesive is a rubber-based,
Emulsion type, solvent type or non-solvent type pressure sensitive adhesives such as acrylic type and vinyl ether type are used.

[0004] Among release papers, glassine release paper is effectively used for performing position detection by a photoelectric tube device by utilizing its transparency in a printing process or a printer labeling process. Further, since a relatively thin release paper can be obtained, it is occupying an important position as an adhesive release paper by making use of the feature that it can have a large area with respect to the winding diameter and the size of the case.

[0005] Glassine release paper is made by using a highly beaten chemical pulp as a raw material, and in order to prevent penetration of the release agent, a base paper is coated with an aqueous coating composition containing a water-soluble polymer or the like as a main component. I have. The coating process is performed during or after the papermaking process. As a coating method, it is manufactured by a scraping method such as blade coating and a roll coater method such as a size press or a gate roll. After that, a glassine release paper is coated with a release agent through a super calendering process. Since glassine release paper is being beaten, drainage is poor and the papermaking speed does not increase. Further, in order to effectively perform the super calendering process, it is necessary to wind the paper after the paper making at a high water content of 8 to 13%. If the moisture in the paper is wound up in a high state, a phenomenon called blocking, in which the papers come into close contact with each other and do not separate, is likely to occur due to a barrier agent or the like.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for efficiently producing release paper.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a base paper for release paper is passed through a calender having at least one nip portion, pressure-treated, and then a coating solution containing a release agent is applied online. A method for producing a release paper. The present invention relates to a method for producing a release paper, further comprising a cooling step of cooling the pressure-treated release paper base paper online between the pressure treatment step and the release agent coating step. The present invention relates to a method for manufacturing a release paper, wherein the calender includes a calender having at least one pair of a metal roll and a nip portion including the metal roll. The present invention relates to a method for producing a release paper in which the pressure condition of the nip is 100 to 3500 kg / cm. The present invention relates to a method for producing a release paper, wherein the pressure condition of the nip portion is 200 to 1200 kg / cm. The present invention provides the calendar device,
The present invention relates to a method for producing a release paper, wherein at least one of the at least one pair of metal rolls has a temperature of 100 to 300C. The present invention is a release paper manufacturing apparatus in which a calender device having at least one nip portion and a device for applying a coating liquid containing a release agent are directly connected.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for producing a base paper for release paper immediately after passing the base paper for release paper through a calender having at least one nip portion and pressing the base paper. By applying a coating solution containing a release agent online, it has become possible to produce release paper with unprecedented high efficiency. In the online described in the present invention, immediately after the base paper for release paper is passed through a calender and subjected to pressure treatment, the coating liquid containing the release agent is continuously applied as it is without winding the processed base paper for release paper. This means that the coating is performed by a coating device directly connected to the calendering device, that is, after the calendering process is completed, the process proceeds to the next process continuously without winding the paper. Further, the direct connection referred to in the present invention refers to a state in which substantially nothing intervenes between the calendering device and the coating device, for example, a tension roll, a guide generally used in a coating machine. A roll or the like may be interposed. Further, the cooling step of the present invention comprises:
This is performed between the calender device and the coating device. The nip portion of the calender having at least one nip portion provided before the step of applying the release agent of the present invention is a combination of an elastic roll and an elastic roll, a metal roll and an elastic roll, and a combination of a metal roll and a metal roll. It is possible.
Among them, a nip portion composed of a metal roll and a metal roll is more effective and preferable. The base paper for release paper used in the present invention is not particularly limited as long as it contains pulp as a main component. Medium paper containing pulp such as DIP or the like or base paper for release paper which has been made into neutral paper can also be used. As the pulp to be used, generally used chemical pulp such as softwood bleached kraft pulp (hereinafter NBKP) and hardwood bleached kraft pulp (hereinafter LBKP), GP, BCTMP, MP
And pulp obtained from non-wood raw materials such as kenaf. Further, coated paper having a coating layer containing a pigment can also be used as a base paper for release paper. In addition, in order to suppress the penetration of the release agent, those obtained by applying the coating composition to the surface of paper after papermaking can also be used as base paper for release paper. Pulp beating degree is 100-60 standard Canadian freeness.
A range of 0 ml is possible. According to the calender device having a nip portion composed of a metal roll and a metal roll of the present invention, it is possible to obtain a transparency equivalent to that of glassine paper without increasing the degree of beating to the level of conventional glassine paper. Papermaking method of base paper for release paper used in the present invention,
Although not particularly limited, a fourdrinier multi-cylinder paper machine, a fourdrinier Yankee paper machine, a round mesh paper machine, or the like can be used. Examples of the water-based coating composition used to suppress the penetration of the release agent used in the present invention include a water-soluble resin and / or a water-dispersible resin, and if necessary, a material containing a pigment as a main component. Here, examples of the water-soluble resin and the water-dispersible resin include the following substances.

The water-soluble resin includes, for example, completely or partially saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol having an acetoacetyl group introduced by reacting polyvinyl alcohol with diketene, polyvinyl alcohol and fumaric acid, phthalic anhydride, and the like. acid,
Trimellitic anhydride, reactants with polycarboxylic acids such as itaconic anhydride or esterified products of these reactants,
Furthermore, carboxy-modified polyvinyl alcohol obtained as a saponified product of a copolymer of vinyl acetate and maleic acid, fumaric acid, itaconic acid, crotonic acid, acrylic acid, and an ethylenically unsaturated carboxylic acid such as methacrylic acid, vinyl acetate and Ethylenesulfonic acid, sulfonic acid-modified polyvinyl alcohol obtained as a saponified copolymer of olefinsulfonic acid such as allylsulfonic acid or a salt thereof, vinyl acetate and ethylene, propylene, isobutylene, α-octene, α-dotecene, α An olefin-modified polyvinyl alcohol obtained by saponifying a copolymer with an olefin such as octadodecene, a nitrile-modified polyvinyl alcohol obtained as a saponified product of a copolymer of vinyl acetate and acrylonitrile, and a nitrile such as methacrylonitrile; Bi acetate Le acrylamide, copolymer saponified amide-modified polyvinyl alcohol obtained by the amides such as methacrylamide, vinyl acetate and N
-Pyrrolidone-modified polyvinyl alcohol obtained by saponifying a copolymer with vinylpyrrolidone, methylcellulose, ethylcellulose, hydroxyethylcellulose,
Cellulose derivatives such as carboxymethylcellulose, and starches such as casein, gum arabic, oxidized starch, etherified starch, dialdehyde starch, and esterified starch.

As the water-dispersible resin, for example, styrene-
Examples thereof include a butadiene copolymer emulsion, a vinyl acetate-vinyl chloride-ethylene copolymer emulsion, and an acrylate copolymer emulsion.

Organic and inorganic fillers can be used as long as the effects of the present invention are not impaired. For example, kaolin, talc, clay, calcium carbonate, calcined clay, titanium oxide, titanium dioxide, diatomaceous earth, fine anhydrous silica, activated clay, zinc oxide, aluminum oxide, aluminum hydroxide, zinc sulfate, barium sulfate, silicon dioxide, colloidal Examples include inorganic pigments such as silica, styrene microballs, urea / formalin resin filler, organic pigments such as nylon powder, polyethylene powder, and raw starch granules.

In the coating liquid for forming a layer for preventing the release agent from penetrating, glyoxal, methylol melamine, potassium persulfate, ammonium persulfate, sodium persulfate, ferric chloride, magnesium chloride, boric acid may be contained, if necessary. , A hardening agent such as ammonium chloride may be added, and if necessary, a lubricant such as zinc stearate, calcium stearate, stearic acid amide, polyethylene wax, carnauba wax, paraffin wax, ester wax, or the like,
Surfactants such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, alginate, metal salts of fatty acids, etc .; ultraviolet absorbers such as benzophenone-based and triazole-based; Various auxiliaries such as coloring dyes can be added as appropriate.

The nip linear pressure under the pressurizing condition of the present invention is 100 k.
If it is less than g / cm, it is difficult to obtain the desired effect of the present invention. If it exceeds 3500 kg / cm, the effect is saturated and the efficiency is not high. By the way, if it is 200 kg / cm or more, it is easy to obtain a desired effect, and if it exceeds 1200 kg / cm, there is some variation depending on the roll diameter and the roll's own weight to be installed, but a structure capable of relatively withstanding the linear pressure is taken. Equipment costs. In this regard, the nip linear pressure is more preferably 200 to 1200 kg / cm. Further, for the same reason, 200 to 500 kg /
cm is most preferred. In particular, it is possible to produce from a high-quality release paper to a release paper having transparency comparable to glassine paper, depending on the release paper base paper used and the calendering conditions.

When the calender of the present invention is formed of a nip portion composed of a metal roll and a metal roll, the surface of the metal roll which is used to suppress the penetration of the release agent is subjected to the calendering process. The base paper for release paper having the transferred shape and high smoothness can be obtained. In particular, since solventless silicone is applied by a method of transferring a thin film, a base paper for release paper made using a calender having a nip portion composed of a metal roll and a metal roll capable of obtaining a highly smooth base paper of the present invention, Suitable for solventless silicone coating.

The temperature of the metal roll treated in the present invention is 1
00 ° C to 300 ° C is preferred. If the roll temperature is less than 100 ° C., it is difficult to obtain barrier properties as release paper and transparency as high as glassine paper. Further, since the amount of heat transmitted to the base paper changes in the optimum temperature range of the roll temperature depending on the paper passing speed, blisters may occur even at a temperature of 300 ° C. or less if the pressing speed is slow. However, generally, when the temperature exceeds 300 ° C., the moisture of the base paper becomes a gas at a stretch, and a volume of the base paper rapidly expands, so that a part of the base paper is partially peeled off, and a blister phenomenon in which the surface expands may occur. is there. In addition, if the same portion of the base paper for release paper is continuously contacted with the roll surface at a temperature exceeding 300 ° C. in a paper passing operation, even if the contact is made for an extremely short time, the paper in the contacted portion may be scorched. Not preferred for safety.

The paper passing speed in the present invention is 1 to 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 base paper under pressure is preferably 2 to 15%, more preferably 3 to 10%, and still more preferably 4 to 10%.
It is effective in the range of 7%. 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,
If it exceeds 15%, the fiber swells too much, causing a phenomenon that a part of the fiber is stretched, and a uniform base paper for release paper cannot be obtained. When at least one of the nip portions of the calender is an elastic roll, it is difficult to obtain transparency comparable to glassine paper unless the paper moisture is in the range of 7 to 15%. However, especially in the case of a calender having a nip portion composed of a metal roll and a metal roll, transparency can be obtained effectively even when the moisture content of the base paper is in the range of 4 to 7%.

After the calendering treatment, the base paper for release paper is at a high temperature, and when applying a thermosetting silicone, the silicone may be cured by heat before a uniform film is formed. After the calendering device, it is more preferable to cool the paper with a cooling device such as a cooling roll or a cool air blowing device.

According to the present invention, a release paper is obtained by applying a coating liquid containing a release agent on-line after passing a base paper for release paper through a calender having at least one nip portion and subjecting the paper to pressure treatment. However, it is of course possible to subsequently finish the obtained release paper to an adhesive sheet online.

FIG. 1 shows an example of the manufacturing method of the present invention. The unwinding roll 1 passes through the nip portion composed of the two rolls 2 and passes through the cooling roll 3 to lower the surface temperature of the release paper base paper, and then proceeds to the release agent coating device 4 where the release agent is removed. Coated. Thereafter, the film is wound up through a drying process to produce a release paper. 5 is a guide roll for guiding the paper to a predetermined position.

[0021]

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 75 parts of LBKP with 420 ml of freeness and NB
Rosin size as a sizing agent in pulp slurry of 25 parts of KP (trade name "Size Pine E", manufactured by Arakawa Chemical Industries)
Was added to the absolutely dry pulp at 0.4%. After adding a sulfuric acid band to the pulp slurry and fixing it, papermaking is carried out with a fourdrinier paper machine, and polyvinyl alcohol (trade name "Px-CVG", manufactured by Unitika Ltd.) at a concentration of 8% is applied on one side with a gate roll. By applying 0 g / m ² , a base paper for release paper having a basis weight of 64 g / m ² was obtained. The water content of the obtained base paper for release paper is 5.5.
%Met.

Examples 1 and 2 A calender having one nip portion composed of a metal roll and a metal roll was placed on a calender having a metal roll temperature of 200 ° C., a linear pressure of 250 kg / cm, and a paper passing before a release agent coating apparatus. Speed 200m / min, (Example 2) metal roll temperature 250 ° C,
After passing the paper under the condition of a linear pressure of 250 kg / cm and a paper passing speed of 300 m / min, the paper surface temperature is 30 ° C. with a cooling roll.
In the state of being lowered to the extent, the film proceeds to a release agent coating device without being wound, and a 5% toluene solution of a release agent (trade name “SD7333”, manufactured by Dow Corning Toray Silicone Co., Ltd.) is applied to the polyvinyl alcohol coated surface. Coating was performed with a bar coater so as to obtain a release paper of 1.0 g / m ² to obtain a release paper.

Example 3 75 parts of LBKP each having a freeness of 450 ml and NB
Rosin size as a sizing agent in pulp slurry of 25 parts of KP (trade name "Size Pine E", manufactured by Arakawa Chemical Industries)
Was added to the absolutely dry pulp at 0.4%. After adding a sulfuric acid band to the pulp slurry and fixing it, papermaking was performed with a fourdrinier paper machine, and polyvinyl alcohol (trade name "PVA117", manufactured by Unitika Ltd.) was applied at a concentration of 6% to 1.0 g / side on a bar coater. m ^{2 was} applied to obtain a base paper for release paper having a basis weight of 80 g / m ² . The water content of the obtained base paper for release paper was 6.1.
%Met.

Before the release agent coating apparatus, paper is passed through a calender having one nip portion composed of a metal roll and a metal roll under the conditions of a metal roll temperature of 55 ° C., a linear pressure of 1000 kg / cm, and a paper passing speed of 200 m / min. Then, with the paper surface temperature lowered to about 20 to 25 ° C by the cooling roll,
Without being wound up, the process proceeds to a release agent coating device, and the release agent (trade name “SD73”) is applied to the polyvinyl alcohol coated surface.
33 ", manufactured by Dow Corning Toray Silicone Co., Ltd.) 5%
The toluene solution was coated with a bar coater so as to be 1.0 g / m ² to obtain a release paper.

Example 4 75 parts of LBKP with 240 ml of freeness and 14 parts
Rosin size (trade name “Size Pine E”, manufactured by Arakawa Chemical Industries, Ltd.) as a sizing agent was added to 0 ml of 25 parts of NBKP pulp slurry in an amount of 0.4% based on the dry pulp.
After adding a sulfuric acid band to this pulp slurry and fixing it, papermaking is carried out with a fourdrinier paper machine, and polyvinyl alcohol (trade name "Px-CVG", manufactured by Unitika Ltd.) at a concentration of 5.4% on one side with a gate roll. 0.5 g / m ² coating, basis weight 6
A base paper for release paper of 0 g / m ² was obtained. The water content of the obtained base paper for release paper was 8.2%.

Before the release agent coating apparatus, a calender having two nip portions composed of a metal roll and an elastic roll is provided with a first nip.
The temperature of the second metal roll is 180 ° C., the temperature of the second metal roll is 200 ° C., the linear pressure is 250 kg / cm, and the paper passing speed is 300.
m / min, the paper surface temperature was lowered to about 30 ° C. by a cooling roll, and then proceeded to a release agent coating device without being wound up. (Trade name “SD7333”, manufactured by Dow Corning Toray Silicone Co., Ltd.) A 5% toluene solution was applied with a bar coater to a concentration of 1.0 g / m ² to obtain a release paper.

Comparative Example 1 A rosin size (trade name "Size Pine E", manufactured by Arakawa Chemical Industry Co., Ltd.) was added as a sizing agent to a pulp slurry of 200% freeness and 100% NBKP to 0.4% of absolutely dry pulp. . After adding a sulfuric acid band to the pulp slurry and fixing it, papermaking is performed with a fourdrinier paper machine, and polyvinyl alcohol (trade name “PC200
0 ", manufactured by Denki Kagaku Kogyo Co., Ltd.) A coating of 1.5 g / m ^{2 was} applied on both sides at a concentration of 5%, and the water content in the paper was reduced to 12% and 64 g.
/ m ² of base paper for release paper was obtained. The winding is performed by a super calender device composed of a metal roll and an elastic roll, at a linear pressure of 200 kg / cm, a metal roll temperature of 130 ° C., and a speed of 35 kg.
It was calendered under the condition of 0 m / min and wound up. Then, a 5% toluene solution of a base paper release agent (trade name "SD7333", manufactured by Dow Corning Toray Silicone Co., Ltd.) was applied to the rolled base paper for release paper using a bar coater.
Coating was performed so as to be 0 g / m ² to obtain a release paper.

An acrylic emulsion-type pressure-sensitive adhesive (trade name “Cybinol SVP-101” manufactured by Siden Chemical Co., Ltd.) was applied to each release paper with a reverse roll coater at 22 g / g.
m ² after coating and drying, the basis weight was 84.9.
g / m ² of cast paper was adhered to obtain an adhesive paper. Table 1 shows the results of evaluating the following items for the obtained pressure-sensitive adhesive paper.

(Peeling Force) A sample of 5 cm × 10 cm having the long side in the flow direction of the adhesive paper was prepared, and INTESCO was prepared.
The peel force when peeling at a tensile angle of 180 degrees in the flow direction under a test condition of 0.3 m / min in the peeling speed was measured with the MODEL 201. (Appropriateness of phototube) The adhesive label finished as a label was checked by an autolabeler whether the phototube of the paper feed detector was able to detect light and whether the label was detectable. ：: Detection with a photoelectric tube is possible. X: Detection with a phototube is impossible. (Production efficiency) The yield when releasing paper was manufactured was examined. ：: High yield. X: The yield is low.

[0031]

[Table 1]

[0032]

According to Examples 1 to 4 and Comparative Example 1, the calendering step is continuously performed before the release agent is applied as compared with the conventional method for producing glassine paper, so that the peeling is comparable to the conventional release paper. Paper could be produced efficiently.

[Brief description of the drawings]

FIG. 1 shows a part of a manufacturing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Unwinding roll 2 ... Nip forming roll 3 ... Cooling roll 4 ... Release agent coating device 5 ... Guide roll

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D21H 23/70 D21H 23/70

Claims (7)

[Claims] A release paper characterized in that a base paper for release paper is passed through a calender device having at least one nip portion and subjected to a pressure treatment, and then a coating liquid containing a release agent is applied online. Manufacturing method. 2. The release paper according to claim 1, further comprising a cooling step of cooling the pressure-treated release paper base paper online between the pressure treatment step and the release agent coating step. Production method. 3. The method for producing a release paper according to claim 1, wherein a calender having at least one pair of metal rolls and a nip portion composed of the metal rolls is used as the calender. 4. The pressurizing condition of the nip portion is 100 to 3500k.
The method for producing a release paper according to claim 3, which is g / cm. 5. The pressurizing condition of the nip portion is 200 to 1200 k.
The method for producing a release paper according to claim 3, which is g / cm. 6. The temperature of at least one of the metal rolls is 10
The method for producing a release paper according to claim 4, wherein the temperature is 0 to 300 ° C. 7. 7. An apparatus for producing a release paper, wherein a calender device having at least one nip portion and a device for applying a coating liquid containing a release agent are directly connected.