JP2015175072A - Base paper for release paper, and release paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a base paper for a release paper for use in a pressure sensitive adhesive sheet, which suppresses occurrence of curling when forming the pressure sensitive adhesive sheet, and has satisfactory paper feed performance and paper alignment performance during a paper discharge in an electrophotographic printer; and the release paper.SOLUTION: A base paper for a release paper is capable of forming a pressure sensitive adhesive sheet for electrophotography by laminating a surface substrate, pressure sensitive adhesive, a release agent, a base coating agent, and the base paper for the release paper. A fiber orientation ratio of the base paper for the release paper to be measured by a supersonic propagation speed measuring device is 1.45-1.70, and a moisture content of paper is 4.5-7.5 mass%. A degree of elasticity of the base paper for the release paper in a width direction of paper to be measured by the supersonic propagation speed measuring device is not more than 4.50 GPa.

Description

  The present invention relates to a base paper for release paper and a release paper suitable for an adhesive sheet that is excellent in paper feedability in an electrophotographic printer and paper alignment at paper discharge.

  The pressure-sensitive adhesive sheet is a sheet in which a pressure-sensitive adhesive layer is formed between the surface base material and the release paper. In recent years, with the progress of the information society, a wide range of commercial, office, household, etc. , Labels, stickers, stickers, emblems, delivery slips, etc. As the surface substrate, paper is mostly used, and as release paper, a release agent such as a silicone compound or a fluorine compound is used on high-density base paper such as glassine paper, clay coated paper, polyethylene laminated paper, etc. The coated one is widely used. As the release agent, a solventless silicone resin is usually used from the viewpoints of release performance, price, and environment and safety. As the pressure-sensitive adhesive, a solvent type, an emulsion type, a hot melt type and the like are used, and among them, an acrylic emulsion type is usually used in view of safety and quality.

  Such pressure-sensitive adhesive sheets are prone to curling, especially when printing with an electrophotographic printer, due to the influence of the heat roll used to fix the toner, curling is likely to occur immediately after printing, causing poor paper feeding and paper ejection. This is a cause of trouble that causes poor paper alignment.

  For example, Patent Document 1 discloses a pressure-sensitive adhesive sheet formed by laminating a surface base material, an adhesive, a release agent, an undercoat agent, and a release substrate, and the surface base material and / or the release substrate is measured by a microwave method. The ratio of the maximum value and the minimum value of the transmitted microwave intensity measured in step 1.0 to 1.3, and the main component of the primer is at least one kind of (meth) acrylic acid ester having a hydroxyl group in the molecule; In addition, a pressure-sensitive adhesive sheet comprising a copolymer and a pigment obtained by emulsion copolymerization with at least one other vinyl monomer copolymerizable therewith has been proposed. Although consideration is given to the aptitude of paper passing through the printer due to the slanting of the paper at the printer and the sticking out of the adhesive, the paper feedability and discharge of the small-sized adhesive sheet at the printer are considered. Is not taken into consideration for the paper alignment of the time, it was inadequate.

  In Patent Document 2, in a pressure-sensitive adhesive sheet obtained by sequentially laminating a release substrate, a release agent, a pressure-sensitive adhesive, and a surface base material, (a) a glass transition temperature of an ethylenically unsaturated carboxylic acid-containing monomer and (b) a homopolymer An ethylenically unsaturated bond-containing monomer having a temperature of 50 ° C. or higher, and (c) another monomer copolymerizable with these monomers (provided that at least one of the monomers (b) and (c)) A glass transition temperature of an acrylate copolymer emulsion obtained by emulsion copolymerization (including an acrylate monomer on one side) is 0 to 100 ° C., and a treatment liquid mainly comprising the copolymer emulsion An adhesive sheet formed by applying or impregnating a surface of the surface base material on which the adhesive is not laminated and applying or impregnating a treatment liquid mainly composed of a water-soluble plasticizer on the surface of the release substrate on which the release agent is not laminated. Has been proposed Fast In an electrophotographic printer is insufficient to suppress the occurrence of curling, remained a problem in the paper alignment of paper discharge.

  In Patent Document 3, in an electrophotographic pressure-sensitive adhesive sheet obtained by laminating at least a release agent layer, a pressure-sensitive adhesive layer, and a surface substrate on a release substrate, water having a glass transition temperature of −10 to 70 ° C. is formed on the surface of the surface substrate. An electrophotographic pressure-sensitive adhesive sheet proposed by applying or impregnating a treatment liquid containing a dispersible polymer as a main component and having a Beck smoothness (JIS P 8119) of the surface base material of 80 seconds / 10 cc or more is proposed. However, high-speed electrophotographic printers are insufficient to suppress the occurrence of curling, and there remains a problem in paper alignment at the time of paper discharge.

JP-A-7-102500 Japanese Patent Laid-Open No. 3-179071 Japanese Patent Laid-Open No. 2-245082

  A base paper for release paper that can solve the above-mentioned problems, can suppress the occurrence of curling, and can constitute a pressure-sensitive adhesive sheet having good paper feedability and paper alignment at the time of paper discharge in an electrophotographic printer, and Release paper was sought.

  The present invention has been made in view of such a situation, and when an adhesive sheet is configured, the occurrence of curling is suppressed, and the paper feedability in an electrophotographic printer and the paper alignability at the time of paper discharge are good. It is an object to provide a base paper for release paper and a release paper for pressure-sensitive adhesive sheets.

  As a result of intensive studies on the feeding property of the adhesive sheet in the electrophotographic printer and the paper alignment property at the time of paper ejection, the inventors measured with an ultrasonic propagation velocity measuring instrument of the release paper base paper constituting the adhesive sheet. By controlling the fiber orientation ratio and paper moisture within a predetermined range, curling is suppressed, and an adhesive sheet with good paper feedability and paper alignment at the time of paper discharge can be obtained. The present invention has been reached.

That is, the present invention has the following configuration.
(1) A base paper for release paper that can be laminated with a base material, an adhesive, a release agent, an undercoat agent, and a base paper for release paper to constitute an adhesive sheet for electrophotography, and the ultrasonic wave propagation of the base paper for release paper A base paper for release paper having a fiber orientation ratio measured by a speed measuring instrument of 1.45 to 1.70 and a water content of 4.5 to 7.5% by mass.
(2) The release paper base paper according to (1), wherein the elastic modulus in the horizontal direction of the paper measured by an ultrasonic propagation velocity measuring instrument of the release paper base paper is 4.50 GPa or less.
(3) The release paper base has a Canadian standard freeness of 100 to 300 ml according to JIS P 8121 and a Runkel ratio (a value obtained by dividing twice the wall thickness of the pulp by the lumen width) from 1.5 to (1) or characterized in that it is composed of 3.5 hardwood bleached kraft pulp fibers, contains a sizing agent, and the undercoat layer contains α-olefin-modified polyvinyl alcohol and a plate-like pigment. The base paper for release paper as described in (2).
(4) The release paper base paper according to any one of (1) to (3), wherein the release paper base paper has a Steecht sizing degree according to JIS P 8122 of 5 to 20 seconds.
(5) JAPAN TAPPI Paper Pulp Test Method No. The base paper for release paper according to any one of (1) to (4), wherein the Oken air permeability according to 5-2: 2000 is 3,000 to 500,000 seconds.
(6) The base paper for release paper according to any one of (1) to (5), wherein the basis weight is 40 to 100 g / m ² .
(7) The peeling according to any one of (1) to (6), wherein the undercoat layer contains 50 to 300 parts by mass of the α-olefin-modified polyvinyl alcohol with respect to 100 parts by mass of the plate pigment. Paper base paper.
(8) Of the above (1) to (7), the α-olefin-modified polyvinyl alcohol contains 1 to 20 mol% of α-olefin, has a polymerization degree of 200 to 8000, and a saponification degree of 80 to 100 mol%. The base paper for release papers of any one of Claims 1.
(9) The base paper for release paper according to any one of (1) to (8), wherein the α-olefin is ethylene.
(10) The base paper for release paper according to any one of (1) to (9), wherein the plate pigment has an aspect ratio of 7 or more.
(11) The release paper base paper according to any one of (1) to (10), wherein a content of the sizing agent is 0.3% by mass or more with respect to the release paper base paper.
(12) The base paper for release paper according to any one of (1) to (11), wherein the sizing agent is a rosin sizing agent.
(13) A release paper in which a release agent layer is provided on the undercoat layer of the release paper base paper described in any one of (1) to (12).

  According to the present invention, when an adhesive sheet is configured, the occurrence of curling is suppressed, and the base paper and the release paper for the adhesive sheet for the adhesive sheet have good paper feedability and good paper alignment at the time of paper discharge in the electrophotographic printer. Paper can be provided.

Hereinafter, embodiments of the present invention will be described in detail.
The base paper for release paper of the present invention comprises a base paper and an undercoat layer provided on at least one surface of the base paper.

(Base paper)
The pulp used to make the base paper of the base paper for release paper of the present invention preferably contains 50% by weight or more of hardwood bleached kraft pulp (hereinafter abbreviated as LBKP). Abbreviated as NBKP), and used paper pulp can be mixed as appropriate. Waste paper pulp includes DIP and waste products generated in the papermaking process. When the uniformity of formation is taken into consideration, the ratio of LBKP is more preferably 70% by mass or more. Moreover, it is possible to mix | blend arbitrary synthetic fibers, a non-wood fiber, etc. as needed.

  It is preferable to adjust the Canadian standard freeness (beatability) of the above pulp to JIS P 8121 to 100 to 300 ml. By setting the Canadian standard freeness (beatability) in the range of 100 to 300 ml, a uniform undercoat layer can be formed in combination with the effect of the sizing agent described later. Moreover, it has moderate paper interlayer strength, and can impart moderate air permeability to the base paper for release paper. A known method can be used as a method for beating the pulp in order to adjust the Canadian freeness (beating degree) to 100 to 300 ml.

  The Runkel ratio (value obtained by dividing twice the wall thickness of the pulp by the lumen width) is preferably 1.5 to 3.5. When a fiber having a Runkel ratio of less than 1.5 is used, the fiber wall thickness is small, so that the undercoat layer coating solution penetrates into the fiber lumen and the peel force may increase. Moreover, since it is inferior in rigidity, the problem that the dimensional stability of release paper deteriorates arises. On the other hand, if the Runkel ratio exceeds 3.5, the shrinkage when heat is applied is large, the curl immediately after printing by the electrophotographic printer becomes large, and there arises a problem that the paper alignability at the time of paper discharge deteriorates.

  Examples of fillers that can be internally added to the base paper for release paper include titanium dioxide, kaolin, talc, heavy calcium carbonate, light calcium carbonate, calcium sulfite, gypsum, calcined kaolin, white carbon, amorphous Silica, Delaminated Kaolin, Diatomaceous Earth, Magnesium Carbonate, Aluminum Hydroxide, Calcium Hydroxide, Magnesium Hydroxide, Zinc Hydroxide and other inorganic pigments, composite pigments carrying different inorganic pigments, urea / formalin resin particles, fine Examples include organic pigments such as hollow particles. Fillers contained in waste paper and waste paper can be reused. The release paper base paper is preferably at least one selected from titanium dioxide, kaolin, talc, and calcium carbonate. Of these, kaolin is particularly preferred for papermaking in the acidic pH region. Calcium carbonate is not preferred for acidic papermaking because it dissolves under acidic conditions. The interlaminar strength of the release paper base paper greatly affects the suitability of the pressure-sensitive adhesive sheet for punching, and the blending amount of the filler is preferably 0 to 25% by mass, more preferably 1 to 20% by mass.

(Size agent)
The base paper of the release paper base paper preferably contains a sizing agent. When the base paper contains a sizing agent, a uniform undercoat layer can be provided in the vicinity of the surface without excessive penetration of the undercoat agent when the undercoat layer described later is applied to the base paper. The sizing agent is originally added for the purpose of preventing the ink from bleeding, but the present invention has found that it has the above-mentioned new effects.

Specific examples of the sizing agent include rosin, alkyl ketene dimer, alkenyl succinic anhydride, styrene-acrylic, higher fatty acid, and petroleum resin. In order to ensure printability and maintain surface properties, papermaking in an acidic pH region is preferable. A rosin-based sizing agent is preferred for imparting sufficient sizing properties in the acidic pH region.
The content of the sizing agent is preferably 0.3% by mass or more with respect to the base paper. When the content of the sizing agent is less than 0.3% by mass, the sizing degree of the release paper base paper is lowered, and there is a possibility that an appropriate air permeability cannot be obtained. The preferable sizing agent content is in the range of 0.4 to 1.5% by mass, and the more preferable sizing agent content is in the range of 0.5 to 1.0% by mass.

  In addition to pulp, filler, and sizing agent, base paper for release paper is used for paper making such as paper strength enhancer, yield improver, pH adjuster, drainage improver, wet paper strength agent, dye / pigment An internally added auxiliary agent can be added as necessary.

  Specific examples of the paper strength enhancer include anionic polyacrylamide, cationic polyacrylamide, amphoteric polyacrylamide, cationic starch, graft copolymer of polyacrylamide and starch, various modified starches, urea resin, polyamide-polyamine resin. , Polyvinyl alcohol, polyethylene oxide and the like. In order to achieve high paper interlayer strength, at least one selected from anionic polyacrylamide, cationic polyacrylamide, amphoteric polyacrylamide, cationic starch, and a graft copolymer of polyacrylamide and starch is preferable.

  Specific examples of the yield improver include polyacrylamide compounds, polyethylene glycol compounds, and polyvinylamine compounds. When titanium dioxide is used as the filler, the overall yield is lowered and the productivity is easily lowered. Therefore, an appropriate yield improver is appropriately selected in order to maintain the productivity.

  Specific examples of pH adjusting agents include sulfuric acid band, aluminum chloride, sulfuric acid, hydrochloric acid, sodium aluminate, basic aluminum compound, sodium hydroxide, potassium hydroxide, ammonia, various primary, secondary, and tertiary. Examples include alkaline compounds such as secondary amines. From the viewpoint of versatility and economy, a sulfuric acid band, sulfuric acid and sodium hydroxide are preferred.

  In order to make the thickness of the release agent layer of the release paper uniform, it is desirable that the base paper of the release paper base paper is well formed. Compared with NBKP, LBKP is relatively thin and short, has few pinholes, and easily forms a uniform texture. In order to form a uniform formation with few pinholes, the blending amount of LBKP is preferably 70% by mass or more of the total raw material pulp. If it is less than 70% by mass, the uniformity of formation becomes insufficient, pinholes are easily formed, and even if a release agent resin is applied, pinholes may remain and cause adhesive residue. In addition, if the formation is not uniform, the punching blade does not have a uniform edge perforation when the adhesive sheet is punched, and the label is not cut well, leading to a rise.

  In the present invention, the fiber orientation ratio measured by the ultrasonic wave velocity measuring instrument of the base paper needs to be 1.45 to 1.70. Incidentally, when the fiber orientation ratio exceeds 1.70, the tendency of the fibers constituting the base paper to be arranged in the vertical direction becomes too strong, the moisture absorption elongation in the horizontal direction becomes large, the curl deteriorates, and the paper feeding property Gets worse. Conversely, if the fiber orientation ratio is less than 1.45, the shrinkage when heat is applied is large, the curl immediately after printing with the electrophotographic printer becomes large, and the paper alignment property at the time of paper discharge may be deteriorated. . A more preferable range of the fiber orientation ratio is 1.50 to 1.65, and 1.50 to 1.60 is particularly preferable.

  Here, the fiber orientation of the base paper refers to the tendency that the pulp fibers flow out onto the wire of the paper machine and are aligned in the outflow (longitudinal) direction in the process of dewatering and forming a paper layer. In other words, since the paper stock flows and dehydrates on the wire at high speed during paper making, there are many fibers oriented in the machine direction (the flow direction of the raw material on the paper machine), and the tensile strength and stiffness in the machine direction are transverse. It is considerably stronger or higher than (width direction). Presumably, such vertical and horizontal differences (non-uniformity) of the base paper increase the elongation in the horizontal direction and deteriorate the dimensional stability due to heat or humidity.

  In general, examples of methods for measuring fiber orientation of paper and the like include ultrasonic methods, thermal expansion methods, mechanical breaking strength methods, X-ray diffraction methods, microwave methods, NMR methods, polarized fluorescence methods, dielectric measurement methods, and the like. It is done. In the present invention, an ultrasonic method is employed, and for example, the ultrasonic propagation velocity (Vmd) in the vertical direction and the ultrasonic propagation velocity (Vcd) in the horizontal direction are measured using “SONICSHEET TESTER” manufactured by Nomura Corporation, and the ratio ( Vmd / Vcd) was used as an index for evaluating the randomness of the fiber orientation with the fiber orientation ratio. When the fiber orientation ratio is 1.0, the fibers are completely random, but in the case of actual machine paper, it has some fiber orientation and cannot be made 1.0 or less.

  On the other hand, since the fiber orientation ratio is determined by the papermaking conditions in the machine, it is necessary to make the operation on the machine appropriate. Possible means include optimization of machine speed, ratio of fiber suspension jet inflow speed to wire speed (J / W ratio), wire shake, homing board and weir board arrangement, dandy roll, and the like. Further, in the operation of the paper machine, the speed of the rear part is generally faster, and paper is made while pulling the paper toward the reel. When this speed difference is increased, the pulp fibers can be oriented in the flow direction. A preferred ratio Vr / Vw of the reel rotation speed (Vr) to the wire rotation speed (Vw) is about 1.010 to 1.050. It is necessary to achieve harmony with other properties such as paper texture while controlling the fiber orientation ratio to be 1.45 to 1.70 by combining one or more of these means. Needless to say.

The base paper for release paper of the present invention preferably has an elastic modulus of 4.50 GPa or less in the transverse direction of the paper measured and calculated using an ultrasonic propagation velocity measuring device (SST-210A, manufactured by Nomura Corporation). If it exceeds 4.50 GPa, the shrinkage due to heat for fixing the toner in the electrophotographic printer is reduced, resulting in an increase in curl immediately after printing, which may deteriorate the paper alignment at the time of paper discharge. A more preferable range of the elastic modulus in the transverse direction of the paper is 4.20 GPa or less, and 4.0 GPa or less is particularly preferable.

(Undercoat layer)
An undercoat layer is provided on at least one surface of the base paper in order to control the release agent resin so as to remain uniformly on the surface of the base paper on the base paper of the base paper for release paper.
In the present invention, the undercoat layer contains α-olefin-modified polyvinyl alcohol and a plate pigment.

(Α-olefin modified polyvinyl alcohol)
As a constituent component of the main chain of the α-olefin-modified polyvinyl alcohol, a polymer obtained by saponifying a polymer containing 80 mol% or more of a vinyl ester typified by a vinyl acetate monomer is preferably used. Since α-olefin-modified polyvinyl alcohol has good film-forming properties, it becomes a film with few pinholes, and it is possible to increase the Oken type air permeability of the base paper for release paper. Moreover, since it is excellent also in barrier property and transparency, it is preferably used.

  When producing α-olefin modified polyvinyl alcohol, vinyl esters other than vinyl acetate, such as vinyl formate, vinyl acrylate, vinyl butyrate, vinyl crotonic acid, vinyl chloroacetate, vinyl oleate, vinyl propionate, vinyl caproate Of course, saturated fatty acid vinyl esters such as vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl pivalate, vinyl versatate can be used instead of vinyl acetate. It is.

  The saponification degree of the α-olefin-modified polyvinyl alcohol in the present invention is present before saponification from the viewpoint that the effect of improving the permeability and adhesive residue of the release agent resin of the obtained resin composition is exhibited to a higher degree. The saponification degree is preferably 80 to 100% in terms of the molar ratio of the saponified ester group to the ester group. From the viewpoint of moisture resistance, the saponification degree is more preferably 90% or more, and most preferably 95% or more.

  As a comonomer component used in an amount of 1 to 20 mol% in addition to the vinyl ester, for example, an α-olefin having 2 to 20 carbon atoms such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene and the like. Can be mentioned. Among these, ethylene is particularly preferably used because it improves the solvent resistance, release agent resin penetration-preventing property and the like of the resulting resin composition and provides a resin composition with excellent characteristics.

  In the present invention, an ethylene-modified polyvinyl alcohol obtained by copolymerizing an α-olefin, particularly ethylene, is preferable because it exhibits good solvent resistance against various solvents such as toluene, methyl ethyl ketone, and hexane. In particular, modified polyvinyl alcohol copolymerized in the ethylene copolymerization ratio range of 1 to 20 mol% is preferable because of excellent balance of solvent resistance, punching workability and the like. When the copolymerization ratio of ethylene is in the range of 1 to 15 mol%, the re-disintegration property of the release paper base paper is remarkably improved, and is several times that of the conventionally used modified polyvinyl alcohol resins other than the α-olefin modified resins. Since it exhibits a degree of re-disaggregation, it is excellent in suitability for recycling as paper after use as release paper. In particular, a base paper for release paper provided with an undercoat layer containing a modified polyvinyl alcohol copolymerized with ethylene in the range of 1 to 9 mol% is most excellent in solvent resistance and punching workability and is optimal. As a method for copolymerization of α-olefin, the comonomer may be copolymerized in the main chain of polyvinyl alcohol, or may be graft-polymerized on the main chain of polyvinyl alcohol.

  The degree of polymerization of ethylene-modified polyvinyl alcohol in the present invention is preferably in the range of 200 to 8000 from the viewpoints of solvent resistance and punching suitability. The degree of polymerization is more preferably in the range of 300 to 2500, further preferably in the range of 400 to 2000, and most preferably in the range of 500 to 1800.

(Plate pigment)
In the undercoat layer used in the present invention, it is necessary to add a plate pigment to α-olefin-modified polyvinyl alcohol. The type of plate pigment is not particularly limited, and inorganic pigments such as kaolin, talc, illite, mica, artificial mica, calcium carbonate, titanium dioxide, aluminum hydroxide, and silica can be appropriately selected and used. In the case of close-packing the pigment, the use of a plate-like pigment as compared with a spherical pigment generally reduces the porosity and can form a dense coating layer, which is preferable in terms of quality.

  As the plate pigment, those having an aspect ratio of 7 or more are preferable. Since the plate-like pigment having an aspect ratio of 7 or more is oriented in the plane direction during coating, a coating layer having excellent barrier properties and smoothness can be easily obtained. Here, the aspect ratio can be obtained by measuring the thickness of the tabular pigment by observation with an electron microscope and dividing the volume average particle diameter of the tabular pigment by the thickness. At this time, the volume average particle size can be determined using, for example, a laser diffraction particle size distribution meter (manufactured by Nikkiso Co., Ltd., “Microtrack MT-3000”).

The average particle size of the plate pigment is preferably 0.2 to 10 μm because of excellent barrier properties and smoothness. The plate pigment preferably has an aspect ratio of 7 or more as shown in the previous section. Further, the plate pigment is preferably excellent in light transmittance.
Examples of the plate pigment having an aspect ratio of 7 or more preferably used in the present invention include kaolin, talc, illite, mica, artificial mica, and aluminum hydroxide.

  The blending amount of the plate pigment and the α-olefin-modified polyvinyl alcohol is preferably 50 to 300 parts by mass of the α-olefin-modified polyvinyl alcohol with respect to 100 parts by mass of the plate pigment. When the blending amount of the α-olefin-modified polyvinyl alcohol exceeds 300 parts by mass, the stain on the cylinder dryer immediately after coating becomes noticeable, the pinhole is not sufficiently covered with the plate pigment, and the effect of improving the adhesive residue is not exhibited. . On the other hand, when the blending amount of the α-olefin-modified polyvinyl alcohol is less than 50 parts by mass, the voids between the pigment and the pigment cannot be sufficiently filled with the α-olefin-modified polyvinyl alcohol, so that many fine voids are generated, and the silicone coating liquid There is a possibility that the penetration into the coating layer and the substrate cannot be suppressed.

The adhesion amount of the undercoat layer is preferably 0.5 to 4.0 g / m ² with respect to the base paper for release paper after drying. If it is less than 0.5 g / m ² , the effect of preventing penetration of the release agent resin becomes insufficient, and the peeling force increases. When the adhesion amount of the undercoat layer is more than 4.0 g / m ² , the peeling force becomes too small and the body tends to be raised.

(Base paper for release paper)
As described above, a base paper for release paper can be obtained by providing an undercoat layer on at least one surface of the base paper of the base paper for release paper.
The sticky sizing degree (measured according to JIS P 8122: 2004) of the base paper for release paper is required to be 3 to 20 seconds. It is preferably about 7 to 15 seconds. The penetration of the release agent and the pressure-sensitive adhesive can be moderately suppressed when the Steecht sizing degree is 5 to 20 seconds. The degree of sizing of the release paper base paper can be controlled by the type and content of the sizing agent, the composition of the undercoat layer, the smoothing treatment described later, and the like.

The basis weight of the base paper for release paper is preferably 30 to 100 g / m ² after humidity control. When it is less than 30 g / m ² , the paper strength is weak and the processability is poor, and when it is higher than 100 g / m ^2, it becomes difficult to impart toner fixing properties.

  As a technique for controlling the surface of the base paper for release paper so as to be uniformly coated with a release agent such as silicone resin, JAPAN TAPPI paper pulp test method No. 1 is used. The Oken type air permeability of the base paper for release paper measured according to 5-2: 2000 can be used. That is, if the Oken type air permeability of the base paper for release paper is less than 3,000 seconds, the release agent resin is soaked too much, and the release performance is hardly exhibited. On the other hand, if it exceeds 500,000 seconds, penetration of the release agent resin is eliminated, the peeling force becomes too light, and the body is likely to rise. The Oken type air permeability of the base paper for release paper is preferably 6,000 to 300,000 seconds, more preferably 10,000 to 250,000 seconds, and particularly preferably 15,000 to 150,000 seconds. is there.

  Moreover, as a technique for controlling the surface of the base paper for release paper so as to be uniformly coated with a release agent such as silicone resin, JAPAN TAPPI paper pulp test method No. 1 is used. The Oken type smoothness of the base paper for release paper measured according to 5-2: 2000 can be used. That is, when the Oken type smoothness is less than 10 seconds, it is difficult to uniformly coat the surface of the base paper with the release agent resin, and when the Oken type smoothness exceeds 500 seconds, the peeling force becomes too light. , It will be easy to rise. The Oken type smoothness of the base paper for release paper is preferably 30 to 300 seconds, more preferably 50 to 250 seconds, and particularly preferably 70 to 200 seconds.

(Manufacturing method of base paper for release paper)
The manufacturing method of the base paper for release paper of this invention is demonstrated.
In the present invention, a hardwood bleached craft having a Canadian standard freeness of 100 to 300 ml according to JIS P 8121 and a Runkel ratio (a value obtained by dividing twice the wall thickness of the pulp by the lumen width) is 1.5 to 3.5. An undercoat layer containing α-olefin-modified polyvinyl alcohol and a plate pigment is applied to at least one surface of a base paper composed of pulp fibers and containing a sizing agent. By doing so, a base paper for release paper having a Steecht sizing degree of 3 to 20 seconds according to JIS P8122 is produced.
Here, paper making using the above papermaking raw materials can be carried out under acidic or neutral conditions using a long web paper machine, twin wire paper machine, on-top paper machine, short paper machine, circular paper machine, Yankee paper machine, etc. Paper is made.

The undercoat layer of the present invention can be applied on-machine or off-machine using various coating apparatuses such as transfer roll coaters, blade coaters, rod blade coaters, air knife coaters, roll coaters, gravure coaters, slot die coaters, curtain coaters, etc. In this manner, at least one side of the base paper is coated in a single layer or multiple layers.
For reasons of operational efficiency, it is preferable to use an on-machine rod metering size press coater.

Furthermore, in this invention, after apply | coating undercoat layer to a base paper, as long as it is dried and the effect is not impaired, a smoothing process can be performed. The smoothing process is performed on-machine or off-machine using a smoothing processing apparatus such as a normal super calender, gloss calender, multi-nip calender, soft calender, or belt nip calender.
By performing the smoothing treatment, the transfer rate of the release agent is improved and the peelability is improved.

The moisture content of the base paper for release paper after the smoothing treatment needs to be 4.5 to 7.5% by mass. By the way, if the moisture content of the base paper for release paper is less than 4.5% by mass, the expansion and contraction when heated is reduced, so the curl immediately after printing with an electrophotographic printer becomes large, and the paper when discharged Alignment deteriorates. On the other hand, when the water content exceeds 7.5% by mass, the curing of the release agent is inhibited, and the peelability is deteriorated.
A more preferable range of moisture in the base paper for release paper is 5.0 to 7.0% by mass, and 5.5 to 6.5% by mass is particularly preferable.

  As described above, the base paper for release paper of the present invention has a fiber orientation ratio and paper moisture measured by an ultrasonic wave velocity measuring instrument of the base paper within a predetermined range, contains a sizing agent, and serves as an undercoat layer. By using an α-olefin-modified polyvinyl alcohol and a plate-like pigment, an undercoat layer that suppresses penetration of the release agent into the vicinity of the surface of the base paper is formed. Is adjusted to a predetermined range, whereby the release agent layer can be uniformly formed in the vicinity of the surface of the release paper base paper. Further, the amount of the release agent such as silicone resin used for forming the release agent layer can be reduced without reducing the release effect.

(Release paper)
In the present invention, a release resin is applied to the release paper base paper in the paper quality range as described above and dried to form a release agent layer, thereby forming the release paper. Examples of the release resin in the present invention generally include silicone resins, fluororesins, amino alkyd resins, polyester resins, etc., but are usually aqueous emulsion type, solvent type or solventless type from the viewpoint of release quality and price. Silicone resin is used. In particular, switching from an aqueous emulsion type to a solventless type is proceeding from the viewpoint of environmental considerations and worker safety, and in the present invention, it is more preferable to use a solventless silicone resin. Among these, a solventless silicone resin having a viscosity at 25 ° C. of 50 to 1,000 mPa · s is more preferable. Examples of the method for applying the release resin include a bar coater, an air knife coater, a direct gravure coater, an offset gravure coater, and a multi-stage roll coater.

The coating amount of the release agent resin is about 0.3 to 1.5 g / ^{m 2} is preferred. When the coating amount is less than 0.3 g / m ² , the amount of the release agent is small and the peeling performance becomes insufficient, and there is a possibility that breakage frequently occurs during label processing. Moreover, when it exceeds 1.5 g / m < ² >, peeling force will become light too much and there exists a possibility that rising may occur frequently. Further, as described above, when the formation uniformity after the release paper is quantified as formation unevenness by transmitted light, the standardized standard deviation is preferably 0.4 or less. If it exceeds 0.4, the formation unevenness gradually increases, resulting in non-uniform per-blade at the time of punching, and the label processing suitability deteriorates. In addition, the higher the compressive modulus in the thickness direction of the release paper, the better the punching suitability. From this point of view, the higher the density of the release paper is preferable.

(Adhesive sheet)
When manufacturing the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive is applied to the surface of the release agent layer of the release paper, dried, and then bonded to the surface substrate. As the pressure-sensitive adhesive, for example, natural rubber, styrene-butadiene copolymer, styrene-isopropylene block copolymer, recycled rubber, synthetic rubber, and other rubber-based, acrylic-based, and silicone-based pressure-sensitive adhesives are appropriately used. . These pressure-sensitive adhesives have forms such as a solvent type, an aqueous emulsion type, a hot melt type, and a liquid curable type. The application amount of the pressure-sensitive adhesive is appropriately adjusted in the range of 10 to 40 g / m ² in terms of dry mass. When the application amount of the pressure-sensitive adhesive is less than 10 g / m ² , the pressure-sensitive adhesive strength is too low, and there is a possibility that the label floats when the label is applied to various adherends. When the application amount of the pressure-sensitive adhesive exceeds 40 g / m ² , the pressure-sensitive adhesive protrudes from the cross-section of the pressure-sensitive adhesive sheet at the time of label punching, and the pressure-sensitive adhesive accumulates to stain or damage the printed surface of the label. In addition, as a method of apply | coating an adhesive, a reverse roll coater, a reverse gravure coater, a barrio gravure coater, a knife coater, a bar coater, a die coater, a curtain coater etc. are mentioned.

  Examples of the surface substrate include high-quality paper, cast-coated paper, art paper, coated paper, thermal paper, inkjet paper, synthetic paper, vapor-deposited paper, various polymer films, etc. Art paper, coated paper, synthetic paper, etc. can be appropriately selected and used according to the purpose.

  The present invention will be described more specifically with reference to the following examples. In Examples and Comparative Examples, “part” and “%” respectively represent “parts by mass” and “% by mass” unless otherwise specified. Moreover, the elasticity modulus showed the elasticity modulus of the horizontal direction of paper unless otherwise indicated.

<Ethylene-modified polyvinyl alcohol 1>
A pressure-resistant reaction vessel equipped with a stirrer, a thermometer, an ethylene introduction tube, a nitrogen introduction tube, and a cooler was charged with 100 parts of vinyl acetate and 30 parts of methanol, and then purged with nitrogen, and then the pressure was adjusted to 3.0 kg / cm 2. Ethylene was injected so that A solution in which 2,2′-azobisisobutyronitrile was dissolved in methanol as a polymerization initiator was prepared, and nitrogen substitution was performed by bubbling with nitrogen gas. The temperature of the reaction vessel charged with the monomer was raised, and when the internal temperature reached 60 ° C., an initiator solution was injected to initiate polymerization. Cooled after 3 hours. Then, it was deethyleneated, and then the unreacted vinyl acetate monomer was removed under reduced pressure to obtain an ethylene-modified methanol solution of polyvinyl acetate. A methanol solution of NaOH (NaOH content of 10% by mass) was added thereto to initiate a saponification reaction. After 1 minute from the addition of the alkaline solution, the resulting gelled product is pulverized with a pulverizer and further allowed to stand for 1 hour to allow the saponification reaction to proceed. Then, methyl acetate is added to the reaction system to remove the remaining alkali. Partially neutralized. White solid-modified polyvinyl alcohol was filtered off, methanol was added thereto, and the mixture was allowed to stand at room temperature for 3 hours, washed, and drained by centrifugation. The denatured polyvinyl alcohol after washing is centrifuged and then dried for 1 day under a nitrogen stream (oxygen concentration 8%) using a drier whose internal temperature is kept at 90 ° C. Got alcohol. This is designated modified polyvinyl alcohol 1.
The modified polyvinyl alcohol 1 had a polymerization degree of 1200, a saponification degree of 98.2 mol%, and an ethylene modification degree of 2.0 mol%.
In the present invention, the degree of polymerization and the degree of saponification were determined according to “3.7 Average degree of polymerization” and “3.5 degree of saponification” of JIS K 6726-1994 “Testing methods for polyvinyl alcohol”. Further, the degree of ethylene modification was determined by analysis by ¹ H-NMR and ¹³ C-NMR. Regarding the degree of ethylene modification, commercially available ethylene-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd .: trade name “EVAL L101” or the like) was used as a standard substance.

<Ethylene-modified polyvinyl alcohol 2>
Modified polyvinyl alcohol was produced in the same manner as modified polyvinyl alcohol 1 except that ethylene was injected so that the pressure was 4.0 kg / cm ² . This is designated modified polyvinyl alcohol 2.
The modified polyvinyl alcohol 2 had a polymerization degree of 1200, a saponification degree of 97.0 mol%, and an ethylene modification degree of 5.2 mol%.

<Ethylene-modified polyvinyl alcohol 3>
Modified polyvinyl alcohol was produced in the same manner as modified polyvinyl alcohol 1 except that ethylene was injected so that the pressure was 7.0 kg / cm ² . This is designated as modified polyvinyl alcohol 3.
The modified polyvinyl alcohol 3 had a polymerization degree of 1200, a saponification degree of 97.4 mol%, and an ethylene modification degree of 16.4 mol%.
<Ethylene-modified polyvinyl alcohol 4>
Modified polyvinyl alcohol was produced in the same manner as modified polyvinyl alcohol 1 except that ethylene was injected so that the pressure was 1.5 kg / cm ² . This is designated modified polyvinyl alcohol 4.
The modified polyvinyl alcohol 4 had a polymerization degree of 1200, a saponification degree of 97.5 mol%, and an ethylene modification degree of 0.5 mol%.

Example 1
(1) Surface base material As a surface base material, a high-quality paper having a basis weight of 52.3 g / m ² (trade name: “GFHW52.3”, manufactured by Oji F-Tex Inc.) was used.

(2) Release paper base paper In Canadian standard freeness 200 ml pulp slurry consisting of 70 parts LBKP (Runkel ratio 1.94) and 30 parts NBKP (Runkel ratio 3.15) Cationized starch (trade name: “Pillar Starch P-3T”, manufactured by Pillar Starch Co., Ltd.) 0.3% as a paper strength agent for absolutely dry pulp, rosin sizing agent (trade name: “Size Pine N” as sizing agent) -776 "(manufactured by Arakawa Chemical Industries, Ltd.) 0.5% and 1.0% sulfuric acid band were added and fixed, and then papermaking was performed with a long paper machine at a papermaking concentration of 0.3%. In a press coater, 100 parts by mass of α-olefin-modified polyvinyl alcohol (ethylene-modified polyvinyl alcohol 1) and kaolin (trade name: “HT”, aspect ratio of 7, Coating the Ruhado Co.) 12% mixture of 100 parts by weight on one side, coating amount to give a release paper base paper having an undercoat layer to be 2.0 g / m ² by dry weight.

The base paper was then subjected to multi-nip calendering, and the JAPAN TAPPI paper pulp test method no. A base paper for release paper according to the present invention in which the smoothness of the undercoat surface by the Oken type smoothness according to 5-2: 2000 was 90 seconds was prepared. The moisture basis weight of the obtained base paper for release paper is 55 g / m ² , the fiber orientation ratio measured by an ultrasonic propagation velocity measuring device is 1.55, the elastic modulus is 3.6 GPa, the paper moisture is 6.0%, JIS P8122 has a strict human size of 7 seconds, JAPAN TAPPI paper pulp test method no. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(3) Adhesive sheet Crosslinking reaction of solvent-free silicone resin (“LTC-1056L” manufactured by Toray Dow Corning Silicone) (viscosity at 25 ° C .: 250 mPa · s) with three offset gravure coaters on the base paper for release paper. 1 g / m ^{2 was} applied and cured to obtain a release paper.

Then, gravure adhesive to the silicone coated surface of the release paper (TOYOCHEM Co. "Oribain BPW6111") was applied and dried so that 20 g / m ² as a solid content, on the opposite side for the curl straightening adhesive coating Watering treatment was performed with a roll, and the surface substrate was bonded to obtain an adhesive sheet.

(Example 2)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the fiber orientation ratio measured by an ultrasonic propagation velocity measuring device was 1.50 in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 8 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 90,000 seconds.

(Example 3)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the fiber orientation ratio measured by an ultrasonic propagation velocity measuring device was 1.41 in the production of the base paper for release paper. The moisture basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 6 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 110,000 seconds.

Example 4
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the fiber orientation ratio measured by an ultrasonic propagation velocity measuring device was 1.63 in the production of the base paper for release paper. The moisture basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 6 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 80,000 seconds.

(Example 5)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the fiber orientation ratio measured by an ultrasonic propagation velocity measuring device was 1.69 in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 90,000 seconds.

(Example 6)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the moisture of the paper was changed to 5.2% in the production of the base paper for the release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 8 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(Example 7)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the moisture of the paper was changed to 4.6% in the production of the base paper for the release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 8 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 120,000 seconds.

(Example 8)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the moisture of the paper was changed to 6.8% in the production of the base paper for the release paper. The moisture basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 6 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 130,000 seconds.

Example 9
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the moisture of the paper was set to 7.3% in the production of the base paper for the release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 110,000 seconds.

(Example 10)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the modulus of elasticity measured by an ultrasonic propagation velocity measuring device was 4.40 in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(Example 11)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that LBKP (Runkel ratio 1.29) and NBKP (Runkel ratio 1.41) were used in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 11 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 90,000 seconds.

(Example 12)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the base paper for the release paper was changed to LBKP (Runkel ratio 3.64) and NBKP (Runkel ratio 3.72). The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 5 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(Example 13)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the α-olefin-modified polyvinyl alcohol was changed to ethylene-modified polyvinyl alcohol 2 in the production of the release paper base paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 9 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 160,000 seconds.

(Example 14)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the α-olefin-modified polyvinyl alcohol was changed to ethylene-modified polyvinyl alcohol 3 in the production of the release paper base paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 12 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 250,000 seconds.

(Example 15)
Example 1 except that the sizing agent was alkenyl succinic anhydride (ASA) (trade name: “Fibran F81K”, manufactured by National Starch Co., Ltd.) in the preparation of the base paper for release paper. Similarly, an adhesive sheet was obtained. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 5 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(Example 16)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 50 parts by mass of α-olefin-modified polyvinyl alcohol (ethylene-modified polyvinyl alcohol 1) was used in the production of release paper base paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the steecht size according to JIS P8122 was 4 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 11,000 seconds.

(Example 17)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 300 parts by mass of α-olefin-modified polyvinyl alcohol (ethylene-modified polyvinyl alcohol 1) was used in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 10 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 360,000 seconds.

(Example 18)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that in the production of the release paper base paper, the coating amount of the undercoat layer was 0.5 g / m ² in terms of dry mass. The moisture basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 6 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 10,000 seconds.

(Example 19)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that in the production of the release paper base paper, the coating amount of the undercoat layer was 4.5 g / m ² in terms of dry mass. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 9 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 600,000 seconds.

(Example 20)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the sizing agent was changed to 0.2% in the production of the release paper base paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the steecht size according to JIS P8122 was 3 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(Example 21)
The same procedure as in Example 1 was performed except that the base layer pigment was kaolin having a high aspect ratio (trade name: “Varisurf HX”, aspect ratio 100, manufactured by Imeris Minerals Japan Co., Ltd.). Thus, an adhesive sheet was obtained. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 8 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 130,000 seconds.

(Example 22)
In the production of the release paper base paper, the same as Example 1 except that the pigment of the undercoat layer was sodium tetrasilicon mica (artificial mica) (trade name: “NTO-5”, aspect ratio 1000, manufactured by Topy Industries, Ltd.). Thus, an adhesive sheet was obtained. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 10 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 400,000 seconds.

(Example 23)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the base layer pigment was talc (trade name: “Shuyen”, aspect ratio of about 7, manufactured by Chuo Kaolin Co., Ltd.) in the production of the release paper base paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 80,000 seconds.

(Example 24)
In the production of the base paper for release paper, LBKP (Runkel ratio 1.29) and NBKP (Runkel ratio 1.41), sizing agent 0.2%, α-olefin modified polyvinyl alcohol 4 ethylene modified polyvinyl alcohol 4, The same as in Example 1 except that the pigment of the undercoat layer was heavy calcium carbonate (trade name: “FMT-90”, indeterminate, manufactured by PMMA Tech), and the coating amount of the undercoat layer was 0.3 g / m 2. Thus, an adhesive sheet was obtained. The moisture basis weight of the obtained base paper for release paper was 55 g / m ² , the Steecht sizing degree according to JIS P8122 was 6 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 3,200 seconds.

(Example 25)
An adhesive sheet was prepared in the same manner as in Example 1 except that the base coat layer was made of heavy calcium carbonate (trade name: “FMT-90”, indeterminate, manufactured by PMMA Tech). Obtained. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the steecht size according to JIS P8122 was 3 seconds, and the JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 6,000 seconds.

(Example 26)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the modulus of elasticity measured by an ultrasonic propagation velocity measuring device was set to 4.47 in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(Comparative Example 1)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the fiber orientation ratio measured by an ultrasonic propagation velocity measuring device was set to 1.42 in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 90,000 seconds.

(Comparative Example 2)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the fiber orientation ratio measured by the ultrasonic wave velocity measuring device was set to 1.25 in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 90,000 seconds.

(Comparative Example 3)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the fiber orientation ratio measured by an ultrasonic propagation velocity measuring device was 1.73 in the production of the base paper for release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

(Comparative Example 4)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the paper moisture was changed to 7.7% in the production of the base paper for the release paper. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 110,000 seconds.

(Comparative Example 5)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the water content of the base paper for release paper was changed to 4.2%. The moisture-control basis weight of the obtained base paper for release paper was 55 g / m ² , the degree of steecht size according to JIS P8122 was 7 seconds, and JAPAN TAPPI paper pulp test method No. The Oken air permeability according to 5-2: 2000 was 100,000 seconds.

<Fiber orientation ratio and elastic modulus>
In accordance with ANSI / ASTM F89-68 “Standard test Method for MODULUS OF FLEXIBLE BARRIER MATERIAL BY SONIC METHOD”, using an ultrasonic propagation velocity meter (SST-210A, manufactured by Nomura Corporation) and a paper orientation ratio The dynamic elastic modulus in the transverse direction was measured and calculated.

<Evaluation of adhesive sheet>
-Curling evaluation A4 size sample was prepared from the obtained adhesive sheet, humidity was adjusted for 4 hours in an atmosphere of 23 ° C / 80% RH, and the curled side was placed on a flat sample table. The average value was obtained by measuring how much the corners were lifted from the sample table, and evaluated according to the following criteria.
: 0 to less than 0.8 cm ○: 0.8 to less than 1.5 cm Δ: 1.5 cm to less than 3.0 cm x: 3.0 cm or more

・ Evaluation of paper feedability A4 size samples are prepared from the obtained adhesive sheet, printed in an atmosphere of 23 ° C and 80% RH, electrophotographic printer “Multifunction device Apeos Port-IV3370” (Fuji Xerox Co., Ltd.) Paper properties were evaluated.
○: Adhesive sheets that could not be fed were within 5 out of 100 sheets, and there was no problem.
(Triangle | delta): The level which may become a problem when the adhesive sheet which could not be fed is 6 to 20 sheets out of 100 sheets.
X: The level of the adhesive sheet that could not be fed was 21 or more out of 100 sheets, causing a problem.

・ Evaluation of paper alignment A4 size sample is prepared from the obtained adhesive sheet and printed with an electrophotographic printer “MFP Apeos Port-IV3370” (Fuji Xerox Co., Ltd.) (paper type: base paper 2 (170-256 g / m) ² )) and evaluated curl and paper alignment at the time of paper discharge.
A: Curling hardly occurs immediately after printing, and the paper alignment property at the time of paper discharge is good.
○: Slight curling occurs immediately after printing, but there is no problem with paper alignment at the time of paper discharge.
Δ: Immediately after printing, the curl is slightly large, and the paper alignment at the time of paper discharge is not stable, causing a problem.
×: Immediately after printing, the curl is large, and the paper alignment at the time of paper discharge is very poor.

-Appropriateness of rising The roll of the adhesive sheet 220 mm width was scraped off at a speed of 20 m / min with a letterpress rotary printing press SKP-250A (manufactured by Sankisha), and the presence or absence of rising was evaluated.
○… No lifting occurred △… Slightly rising ×… Booming occurred

-Adhesive residue evaluation It evaluated by the amount of glue adhering to a roll in the above-mentioned applicability evaluation process.
○: Adhesive residue hardly occurs Δ: Adhesive residue is somewhat ×: Adhesive residue is very conspicuous

-Peeling evaluation The force (g / 50mm) required to peel an adhesive label at an angle of 180 ° using a tensile tester was measured. The pulling speed was 10 m / min. It was determined that 200 g / 50 mm or more was inferior in peelability.

Table 1 shows the results obtained in the examples and comparative examples.

As is apparent from Table 1, Examples 1 to 26 in which the fiber orientation ratio and the paper moisture measured by the ultrasonic wave propagation velocity measuring device of the release paper base paper were controlled within a specific range were 23 ° C./80% RH. The paper was excellent in curling under the environment and paper alignment at the time of paper feeding with an electrophotographic printer. In addition, if the Canadian standard freeness of pulp, Runkel ratio, undercoat layer type (resin type, pigment type), coating amount, and steecht size are controlled within specified ranges, adhesive residue, rise and peeling There was no problem in both strength and phototube suitability (opacity). Further, the air permeability was also in a preferable range. On the other hand, Comparative Examples 1 to 5 deviating from the range defined in claim 1 were curls in an environment of 23 ° C./80% RH, or an electrophotographic printer. It was inferior in the paper alignment at the time of worship.

  When paper is ejected from curls or electrophotographic printers, the adhesive sheet is made up of a base paper for release paper that controls the fiber orientation ratio and paper moisture measured by an ultrasonic wave velocity meter within a specific range. A product with good paper alignment can be obtained.

Claims (13)

  A base paper for release paper, which can constitute an electrophotographic pressure-sensitive adhesive sheet by laminating a surface base material, an adhesive, a release agent, a primer, and a base paper for release paper, and an ultrasonic propagation velocity measuring instrument for the base paper for release paper A base paper for release paper, characterized in that the fiber orientation ratio measured by 1 is 1.45 to 1.70, and the paper moisture is 4.5 to 7.5% by mass.   The base paper for release paper according to claim 1, wherein the elastic modulus of the cross direction of the paper measured by an ultrasonic propagation velocity measuring device of the base paper for release paper is 4.50 GPa or less.   The release paper base has a Canadian standard freeness of 100 to 300 ml according to JIS P 8121 and a Runkel ratio (a value obtained by dividing twice the wall thickness of the pulp by the lumen width) of 1.5 to 3.5. The hardwood bleached kraft pulp fiber is used to contain a sizing agent, and the undercoat layer contains α-olefin-modified polyvinyl alcohol and a plate-like pigment. Base paper for release paper.   The release paper base paper according to any one of claims 1 to 3, wherein the release paper base paper has a Steecht sizing degree according to JIS P 8122 of 5 to 20 seconds.   JAPAN TAPPI Paper Pulp Test Method No. The base paper for release paper according to any one of claims 1 to 4, wherein the Oken air permeability according to 5-2: 2000 is 3,000 to 500,000 seconds. Basis weight is 40-100 g / m < ² >, The base paper for release papers of any one of Claims 1-5.   The base paper for release paper according to any one of claims 1 to 6, wherein the undercoat layer contains 50 to 300 parts by mass of the α-olefin-modified polyvinyl alcohol with respect to 100 parts by mass of the plate pigment.   8. The α-olefin-modified polyvinyl alcohol contains 1 to 20 mol% of α-olefin, has a polymerization degree of 200 to 8000, and a saponification degree of 80 to 100 mol%. Base paper for release paper.   The base paper for release paper according to any one of claims 1 to 8, wherein the α-olefin is ethylene.   The base paper for release paper according to any one of claims 1 to 9, wherein the plate pigment has an aspect ratio of 7 or more.   The base paper for release paper according to any one of claims 1 to 10, wherein a content of the sizing agent is 0.3% by mass or more based on the base paper for release paper.   The base paper for release paper according to any one of claims 1 to 11, wherein the sizing agent is a rosin sizing agent.   Release paper which provided the release agent layer on the undercoat layer of the base paper for release paper of any one of Claims 1-12.