JP2006144178A - Method for producing coated paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing coated paper having a stable quality and operating property jointly by preventing the tip end part of a coating blade from softening and deforming caused by the frictional heat between the coating blade and web in a coating method by using the coating blade having a low hardness. <P>SOLUTION: This blade coater supplying coating liquid on the traveling web and coating with a prescribed amount of the coating liquid by the coating blade is characterized by using the coating blade consisting of a tip end part for scraping the coating liquid by making it contact with the web and having 50-100 Shore A hardness, and a blade parent material for energizing the tip end part to the web and having a different raw material from the tip end part, and supplying liquid for cooling or lubricating on the web just before coming in contact with the tip end part or on a contacting part of the web with the tip end part at a stopped time before starting the coating and in joining an old stock paper roll under coating with the beginning end part of a new stock paper roll in traveling state, while making the tip end part contact with the web in a state that the coating liquid is not supplied on the web. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing coated paper. More specifically, the present invention relates to a method for producing coated paper having a long coating blade life, excellent operational stability, excellent base paper coverage, and good and stable. The present invention relates to a method for producing a coated paper suitable for an image material that enables the image reproducibility.

  The blade coater is one of the methods for producing coated paper, and has recently become mainstream due to its wide coating amount control range and good production efficiency. In this blade coater, when the old paper roll being coated and the starting edge of the new paper roll are spliced in the running state, the coating liquid is not supplied to the web (hereinafter referred to as dry touch). When the blade comes into contact with the web, the frictional heat generated softens the blade, deforms into a wavy shape, and the coating amount profile in the paper width direction after coating restarts becomes non-uniform, resulting in poor coating quality. There was a problem. With respect to this, a thermal deformation preventing device (for example, refer to Patent Document 1) or a minute angle that blocks the heat transfer from the tip of the blade to the abdominal surface by acting a coolant on the abdominal surface of the blade or the blade holder. A coater head thermal deformation prevention and correction device (for example, see Patent Document 2) that detects the amount of thermal deformation during operation by a detection device and automatically adjusts the flow rate of the coolant or the heat medium to correct the thermal deformation. Has been.

In blade coating, in addition to the above-mentioned paper splicing, dry touch always occurs at the start and stop of coating, but when using metal blades and ceramic blades that have been mainstream in the past, coating start and stop Since the running speed of the web at this time was low, the thermal deformation did not occur, and this did not cause a problem. However, the coating blade having a low hardness tip in the present invention has the advantages of good base paper coverage and ease of application of the coating amount, even at low speeds at the start and stop of coating. There was a problem of thermal deformation. In addition, since the thermal conductivity of the tip portion is poorer than that of metal, even if a coolant is applied to the blade belly surface or the blade holder, the tip portion cannot be sufficiently cooled. For this reason, not only paper splicing during running but also streaky surface due to deterioration of the coating amount profile in the paper width direction resulting from softening deformation due to frictional heat and partial peeling of the tip even at the start and stop of coating performed at low speed Due to the quality, it was not put into practical use.
JP-A-57-147477 Japanese Utility Model Publication No. 59-102176

  An object of the present invention is to solve the above-mentioned problems, and in a coating method using a coating blade with low hardness, softening deformation of the blade tip due to frictional heat between the coating blade and the web is prevented. By doing so, a method for producing a coated paper having both stable quality and operability is provided.

  As a result of diligent research in view of the above, the present inventor made contact with the tip when using a coating blade composed of different materials of the tip and the blade base material and having a relatively low hardness at the tip. The present inventors have invented a method for producing coated paper, characterized in that a liquid is supplied to the web immediately before or the contact portion between the tip and the web and cooled or lubricated.

  That is, the present invention provides a coating paper manufacturing method in which a coating liquid is supplied onto a traveling web and then applied to a desired coating amount by a coating blade, and the coating liquid is scraped in contact with the web. Using a coating blade comprising a tip having a hardness of 50 to 100 at Shore A to be taken and a blade base material made of a material different from the tip that biases the tip to the web, And the front end of the new base paper roll and the base end of the new base paper roll that are being coated in the running state, while the tip is in contact with the web without supplying the coating liquid, the tip The liquid is supplied to the web immediately before the portion contacts or the contact portion between the tip and the web, and cooled or lubricated.

  Further, the second invention is characterized in that the liquid is sprayed by mist shower as the method for adhering the liquid of the first invention.

  The third invention is characterized in that a liquid showing 5 to 100 mPa · s is sprayed in the Brookfield viscometer described in JIS Z8803 as the liquid in the first or second invention.

  The fourth invention is characterized in that the temperature of the liquid in any one of the first to third inventions is 20 ° C. or less.

  The fifth invention is characterized in that the liquid according to any one of the first to fourth inventions contains a lubricant.

  According to the present invention, in the coating method using the coating blade with low hardness, which is excellent in image reproducibility because of excellent base paper coverage, the start and stop of coating, and the old base paper roll and the new base paper roll during coating The target coated paper could not be obtained due to non-uniform coating amount profile and streaky surface quality due to thermal deformation due to frictional heat in dry touch when splicing the starting edge of the base paper while running Further, it is possible to provide a method for producing a coated paper having both stable quality and operability by preventing generation of frictional heat between the coating blade and the web by cooling and lubrication.

  Hereinafter, the manufacturing method of the coated paper using the coating blade according to the present invention will be described in detail.

  An object of the present invention is to stably provide a coated paper using a coating blade that gives a quality advantage with respect to a coating layer. Hereinafter, the description will be made with reference to the drawings in relation to applying the coating liquid onto the moving web.

  As shown in FIG. 1, the coating blade according to the present invention includes a tip 2 that contacts the web 3 and scrapes the coating solution 6, and a tip 2 that biases the tip 2 toward the web 3. Is composed of a blade base material 1 made of different materials, and the blade base material 1 is made of steel or other shape-stabilizing material. The blade base material 1 is brought into contact with the web 3 and scrapes off an excessive coating liquid. A tip portion 2 made of a material different from the blade base material 1 intended to be taken is provided. A portion of the blade base material 1 having the tip portion 2 opposite to the tip portion 2 is installed in a clamp 7 which is a blade holding member, and the blade base material is moved by moving the clamp 7 toward the backing roll 4. 1 is deflected, and as a reaction force, a pressing pressure is generated on the tip 2 in contact with the web 3, and the coating liquid 6 is scraped off to measure the coating amount. Reference numeral 5 denotes a fountain applicator, which adheres the coating liquid 6 to the web 3.

  When the tip 2 of the coating blade is made of a material with a relatively low hardness, that is, a material having a Shore A hardness of 50 to 100, a considerable advantage can be obtained. Okay, but in the dry touch when the start and stop of coating and the old paper roll being coated and the starting edge of the new paper roll are spliced in the running state, thermal deformation due to frictional heat and partial peeling of the tip The target coated paper could not be obtained due to the uneven coating amount profile and streaky surface quality.

  Therefore, in the dry touch, while the tip is in contact with the web in a state where no coating liquid is supplied to the web, the web immediately before the tip 2 of the coating blade contacts or the tip 2 and the web A liquid is supplied to the contact portion and cooled or lubricated. As a method of supplying liquid to the web or the contact portion between the tip 2 and the web, liquid supply equipment such as a roll application and a fountain application, a shower pipe having a plurality of holes along the width direction of the web, and a web Directly spraying liquid while scanning the liquid supply means along the width direction, spraying vapor or vaporized liquid, etc., and combinations of these methods can be applied, but they do not cause problems such as running out of paper, From the viewpoint of uniformity of the adhered liquid, economy due to the simplicity of the apparatus, and the like, a liquid spraying method using a mist shower is more preferable.

  Specifically, the liquid spraying method using the mist shower is to uniformly eject the liquid supplied from the liquid tank 12 and the air supplied from the air compressor 13 from the mist shower device 8 as the mist shower 9 in the width direction, This is a method of attaching to the web 3. Thereby, generation | occurrence | production of the frictional heat which generate | occur | produces between the front-end | tip part 2 and the web 3 can be suppressed, and the thermal deformation and peeling of the front-end | tip part 2 can be prevented by cooling.

  As a position to which the liquid according to the present invention is attached, the web immediately before the tip portion 2 and the web contact each other is most desirable. This is because frictional heat is generated because the liquid penetrates the web and does not show a predetermined lubrication effect as the adhesion position is upstream of the web, particularly in a paper base having liquid permeability. This is because there is a high possibility that heat suppression will be induced. Also, the method of attaching the liquid to the contact point between the tip and the web is the best in terms of cooling effect because the contact point is a source of frictional heat, but the lubrication effect is small as the liquid adheres to the tip. As a result, the method in which the liquid is attached to the web immediately before the tip portion and the web come into contact with each other is more effective.

  In addition, when the viscosity of the liquid to be adhered shows 5 to 100 mPa · s in the Brookfield viscometer, the frictional heat generated between the tip portion 2 and the web 3 is remarkably suppressed by improving the lubricity, Further, when the web 3 is a material that penetrates a liquid such as paper, the lubrication effect and the cooling effect are improved by preventing the web 3 from penetrating, so that the effect of preventing thermal deformation is large and more preferable. When the viscosity is lower than 5 mPa · s, the above effect is lowered. When the viscosity exceeds 100 mPa · s, it becomes difficult to spray the liquid due to the viscosity, and the adhesion method is limited.

  Examples of the viscosity-imparting agent that imparts viscosity to the liquid include starches such as sweet potato starch, potato starch, wheat starch, tapioca starch, and corn starch, carrageenan, laminaran, seaweed mannan, funari, Irish moss, agar, and alginates. Plant agglomerates such as mango, quince seed, pectin, tragacanth gum, karaya gum, xanthine gum, guar gum, locust bean gum, tamarind seed gum, arabic gum, carob gum, and benzoin gum Homopolysaccharides such as dextran, glucan, xanthan gum, and levan, and microbial mucilages such as heterosaccharides such as succinoglucan, pullulan, curdlan, and xanthan gum, tongues such as glue, gelatin, casein, and collagen Natural polymer compounds of click quality or the like,

  In addition to propylene glycol alginate, fiber elements such as viscose, methylcellulose, ethylcellulose, methylethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylcellulose, carboxymethylhydroxyethylcellulose, and hydroxypropylmethylcellulose phthalate Derivatives, modified gums such as carboxymethyl guar gum, hydroxypropyl guar gum, and hydroxyethyl guar gum, baked starch such as white dextrin, yellow dextrin, and bridish gum, enzyme modified dextrins such as enzyme dextrin and shardinger dextrin, solubilized starch Acid-degraded starch such as Oxidized starch such as hydr starch, pregelatinized starch such as modified and non-modified pregelatinized starch, phosphate starch, fatty acid starch, sulfate starch, nitrate starch, xanthate starch, and esterified starch such as carbamic acid starch, Hydroxyalkyl starch, carboxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamylethyl starch, and etherified starch such as dialkylamino starch, methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphate crosslinked starch, And crosslinked starch such as dicarboxylic acid crosslinked starch, starch polyacrylamide copolymer, starch polyacrylonitrile copolymer, cationic starch polyacrylate copolymer, cationic starch vinyl polymer copolymer, starch polystyrene / maleic acid copolymer Coalescence And starch semi natural products such processed starch of the starch graft copolymer such as polyethylene oxide copolymer (semisynthetic),

In addition to polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, modified polyvinyl alcohol such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, polyacrylate, polyacrylate ester partial saponified product, polymethacrylate And polyacrylic acid derivatives such as polyacrylamide and polymethacrylic acid derivatives, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer, styrene / maleic acid copolymer, styrene / Examples include organic compounds conventionally known as binders and thickeners, such as synthetic polymer compounds such as crotonic acid copolymers, and inorganic compounds such as silicates and clay minerals. In addition, a paper strength agent used for internal addition of papermaking may be used. The adhering amount when adhering these is preferably a lower limit value of 10 ml / m ² or more, and an adhering amount that does not cause paper breaks as the upper limit. However, with paperboard or the like, it is difficult for paper breakage to occur, so the upper limit is that the surroundings are not soiled with liquid splashes from the web.

  Further, when the temperature of the liquid to be deposited is 20 ° C. or less, the effect is enhanced. This is because by making the temperature 20 ° C. or less, the cooling effect is improved and the effect of preventing thermal deformation is enhanced.

  Further, when the liquid to be adhered contains a lubricant, the effect is clearly enhanced. This is because the lubricant contained in the liquid suppresses the generation of frictional heat generated between the tip of the coating blade according to the present invention and the web and increases the effect of preventing thermal deformation.

  Conventional lubricants such as molybdenum disulfide, tungsten disulfide, graphite, graphite fluoride, calcium fluoride, fluororesin, polytetrafluoroethylene, melamine cyanurate, boron nitride, polyamide, etc. As well as silicone oils, higher fatty acid amides such as oleic acid amide and erucic acid amide, metal salts of higher fatty acids such as bis fatty acid amide, calcium stearate and zinc stearate, liquid paraffin, polyethylene wax and polypropylene wax and Examples include hydrocarbon lubricants such as fluorocarbon oils, higher alcohol esters, fatty acid esters of polyhydric alcohol esters, silicone oils, higher fatty acid amides, bis fatty acid amides, hydrocarbon lubricants, and fatty acid metal salts.

  Representative examples of fatty acid metal salts (also called metal soaps) include lauric acid, stearic acid, succinic acid, stearyl lactic acid, lactic acid, phthalic acid, benzoic acid, hydroxystearic acid, ricinoleic acid, naphthenic acid, oleic acid, palmitic acid , Compounds of higher fatty acids such as erucic acid and metals such as Li, Na, Mg, Ca, Sr, Ba, Zn, Cd, Al, Sn, and Pb, and preferred ones include magnesium stearate, calcium stearate, Sodium stearate, zinc stearate, calcium oleate, zinc oleate, magnesium oleate and the like. The present invention is not limited to these.

The lubricant may be used as it is without being diluted or diluted with a suitable solvent, but it is preferable to use it by dissolving or dispersing in water in consideration of workability and the like. In the case of dispersing in water, a surfactant exhibiting an action such as a dispersant or an emulsifier may be used in combination. The concentration of the lubricant in the solvent or dispersion medium containing water is preferably 5% by mass or more. The adhering amount when adhering these is desirably a lower limit value of 5 ml / m ² or more, and an adhering amount that does not cause a paper break as an upper limit. However, with paperboard or the like, it is difficult for paper breakage to occur, so the upper limit is that the surroundings are not soiled with liquid splashes from the web.

  The coated paper produced in this way is deformed by its elasticity at the tip that is in contact with the moving web, adapts to the unevenness of the web surface to some extent, and the pressure distribution at the contact portion becomes uniform, As long as the softening deformation of the blade tip due to frictional heat between the coating blade and the web is prevented, the coating layer has the desirable effect of covering the unevenness of the web evenly compared to a metal or ceramic blade with high hardness. A uniform product can be obtained with stable operability.

  It is preferable that the tip part 2 installed in the coating blade according to the present invention has a Shore A hardness of 50 to 100. As for the hardness, if the hardness is too high, the base paper covering property derived from the elasticity of the tip portion is deteriorated. If the hardness is too low, the durability of the tip portion is adversely affected and the life is shortened. Therefore, it is more preferable that the Shore A hardness is in the range of 70-80.

  The tip angle of the tip of the coating blade according to the present invention is preferably 3 to 40 °. The coated paper produced with a blade having a tip angle of 3 to 40 ° at the tip is made uniform because the entire pressure distribution is uniform while the maximum pressure applied between the tip and the web is reduced. It has the effect of further improving the base paper coverage.

  The tip portion in the present invention can be composed of an organic polymer. Examples of useful polymers include polyurethanes, styrene / butadiene polymers (ie rubber type polymers) and polyolefins, with a particularly preferred type of polymer being polyurethanes. The polyurethane tip material is composed of polyols and diisocyanates in the usual manner. Common diisocyanates for polyurethane systems are toluene diisocyanate, diphenylmethane diisocyanate and naphthalene diisocyanate. In addition, diisocyanates with low popularity can be used, for example, hexamethylene diisocyanate and isophorone diisocyanate. As polyurethanes, for example, urethanes based on ester urethanes, ether urethanes and hydroxyl-terminated polybutadienes can be used.

  The blade matrix 1 used in the coating blade according to the invention suitably has a thickness in the range of 0.2 to 2 mm. The installed tip 2 suitably has a thickness in the range of 0.1-5 mm. Further, the width of the tip portion 2 viewed from the plane of the blade at a right angle to the longitudinal direction is appropriately 5 to 25 mm, but this dimension is not particularly essential.

  In the present invention, the “coating liquid” refers to a pigment coated paper coating liquid in which an inorganic or organic pigment is dispersed, an ink jet recording paper coating liquid, a thermal recording paper coating liquid, and a color former and a developer. And a microcapsule containing a color former or a developer in which a developer is dispersed as a coating solution for pressure-sensitive recording paper.

  In the present invention, the pigment used in the coating liquid is not particularly limited. For example, purified natural mineral pigments such as various kaolins, calcined kaolins, silica, alumina, talc, pulverized calcium carbonate, satin white, and lithopone. And synthetic resin pigments such as titanium oxide, semi-synthetic pigments such as precipitated calcium carbonate and aluminum hydroxide, organic dense pigments, and organic hollow pigments.

  The binder is not particularly limited. Examples of starch include ordinary starch, oxidized starch, etherified starch, esterified starch, enzyme-modified starch, and cold water soluble starch obtained by flash drying them. Is mentioned.

  Further, as a thickener used in the coating solution, water-soluble polymers such as carboxymethylcellulose, sodium alginate, methylcellulose, hydroxyethylcellulose, casein, sodium polyacrylate, polyacrylate, styrene maleic anhydride copolymer And synthetic polymers such as silicate and inorganic polymers such as silicate.

  As binders other than starch, various latexes such as styrene / butadiene, acrylic and vinyl acetate, polyvinyl alcohol, sodium polyacrylate, polyethylene oxide, polyacrylamide, urea or melamine / formalin resin, polyethyleneimine, polyamide polyamine / Examples thereof include water-soluble synthetic compounds such as epichlorohydrin, natural products such as wax, casein and soybean protein, and those obtained by cationizing these.

  Further, if necessary, various commonly used auxiliaries such as a dispersant, an antifoaming agent, a water-resistant agent, a colorant, a cationizing agent, a lubricant, and those obtained by cationizing these various auxiliaries are suitable. Used for.

  In the present invention, the base material for coating which is a web to which the coating liquid is applied includes chemical pulps such as LBKP and NBKP, mechanical pulps such as GP, PGWRMP, TMP, CTMP, and CGP, and various pulps such as waste paper pulp. Contains various fillers such as light calcium carbonate, heavy calcium carbonate, talc, clay, kaolin, sizing agent, fixing agent, retention agent, paper strength enhancer, etc., acidic, neutral, A paper made of any one of alkalis can be used. In addition, although synthetic paper, a film, and a nonwoven fabric are also used as a base material, Preferably the smoothness by Parker print surf is 8 micrometers or more and 20 micrometers or less.

  In the base paper according to the present invention, no-size press base paper, base paper size-pressed with starch, polyvinyl alcohol, or the like can be used. Further, various calendar processes may be performed to obtain the required density and smoothness of the base paper. Further, the coated paper for offset rotary printing that has been coated and dried in a series of operations is subjected to various calendar processes as necessary.

In this invention, as a coating amount, it is 1-40 g / m < ² > as dry mass, Preferably it is 2-30 g / m < ² >.

  In the present invention, the layer structure of the coating layer is not particularly limited to a single layer, and may be two or more coating layers as necessary.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, unless otherwise indicated, all the parts and% in an Example show a mass part and mass%.

Example 1
<Base paper formulation>
LBKP (freeness 440 mlcsf) 70 parts NBKP (freeness 490 mlcsf) 30 parts

<Internal medicine>
Calcium carbonate (* expressed as ash content in base paper) * 8 parts cationized starch 1.0 parts cationic polyacrylamide yield improver 0.03 parts Pulp and internal additives are adjusted according to the above formulation, basis weight 70 g / m ² Paper was made.

<Composition of coating liquid>
Fine kaolin clay 20 parts Primary kaolin clay 50 parts Heavy calcium carbonate 30 parts Polyacrylic acid dispersant 0.1 part Latex binder (styrene / butadiene) 10 parts Phosphate ester starch 5 parts Sodium hydroxide Adjusted to pH 9.6

<Specifications of elastic blade>
Blade base material width 81mm
Blade thickness 0.4mm
Tip thickness 0.2mm
Width of tip 15mm
Tip angle of tip 10 °
Tip hardness (Shore A hardness) 75

<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Immediately before contacting the tip of the coating blade Web (9 positions in Fig. 1)
Liquid content Water-liquid viscosity 0.6 mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

For the base paper obtained as described above, the coating liquid is prepared by the above-mentioned formulation, and the coating liquid is applied at a coating speed of 500 m / min using a fountain application / bent blade type coating machine having a coating width of 2 m. A solid content of 10 g / m ² on one side was applied and dried to obtain a coated paper.

  For the obtained coated paper, using a super calender device (number of steps: 10 steps, rigid roll: chilled roll having an outer diameter of 400 mm, elastic roll: cotton roll having an outer diameter of 400 mm, linear pressure: 220 kN / m) offline. The calendering process was performed and the coated paper of Example 1 was manufactured.

Example 2
In Example 1, the coated paper of Example 2 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Immediately before contacting the tip of the coating blade Web (9 positions in Fig. 1)
Liquid content 1% aqueous solution of polyvinyl alcohol Liquid viscosity 10mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Example 3
In Example 1, the coated paper of Example 3 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Immediately before contacting the tip of the coating blade Web (9 positions in Fig. 1)
Liquid content 5% polyvinyl alcohol aqueous solution Liquid viscosity 80mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Example 4
In Example 1, the coated paper of Example 4 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Immediately before contacting the tip of the coating blade Web (9 positions in Fig. 1)
Liquid content 8% polyvinyl alcohol aqueous solution Liquid viscosity 130mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Example 5
In Example 1, the coated paper of Example 5 was produced in the same manner as in Example 1, except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Immediately before contacting the tip of the coating blade Web (9 positions in Fig. 1)
Liquid content 5% aqueous solution of polyvinyl alcohol Liquid viscosity 85mPa · s
Liquid temperature 15 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Example 6
In Example 1, the coated paper of Example 6 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above-mentioned dry touch time) 7 seconds Liquid adhesion method Direct spraying liquid adhesion position Web just before contacting the tip of coating blade (9 positions in Fig. 1)
Liquid content Water-liquid viscosity 0.6 mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec

Example 7
In Example 1, a coated paper of Example 7 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Immediately before contacting the tip of the coating blade Web (9 positions in Fig. 1)
Liquid content 30% fluororesin water dispersion liquid viscosity 80mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Example 8
In Example 1, the coated paper of Example 8 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Web upstream of fountain applicator (Fig. 1) 10 positions)
Liquid content Water-liquid viscosity 0.6 mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Example 9
In Example 1, the coated paper of Example 9 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Contact between tip of coating blade and web Point liquid content Water liquid viscosity 0.6mPa · s
Liquid temperature 35 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Example 10
In Example 1, a coated paper of Example 10 was produced in the same manner as in Example 1 except that the liquid adhesion conditions for dry touch were as follows.
<Liquid adhesion conditions for dry touch>
Web speed at start and stop of coating 100m / min Dry touch time 5 seconds Liquid adhesion time (including the above dry touch time) 7 seconds Liquid adhesion method Mist shower spraying liquid adhesion position Immediately before contacting the tip of the coating blade Web (9 positions in Fig. 1)
Liquid content 30% fluororesin water dispersion liquid viscosity 85mPa · s
Liquid temperature 15 ℃
Liquid supply rate 300ml / sec Air supply rate 300ml / sec

Comparative Example 1
In Example 1, a coated paper of Comparative Example 1 was produced in the same manner as Example 1 except that the liquid at the time of dry touch was not adhered.

Comparative Example 2
In Example 1, the coating of Comparative Example 2 was performed in the same manner as in Example 1 except that the liquid at the time of dry touch was attached to the coating blade from the back surface (11 position in FIG. 1). Paper was manufactured.

Comparative Example 3
A coated paper of Comparative Example 3 was produced in the same manner as in Example 1 except that a metal blade having the following specifications was used instead of the coating blade in Example 1.
<Specifications of metal blade>
Blade width 81mm
Blade thickness 0.4mm
Tip angle 10 °

  About the coated paper for printing obtained by the said Examples 1-9 and Comparative Examples 1-3, after sampling the 2000m part after the newly installed braid | blade coating, it evaluated by the following evaluation method, The result is shown. It was shown in 1.

<Evaluation method>
(1) Combustion test In the combustion test, when the coated paper is moistened with an approximately 10% ammonium chloride solution and the coated paper is heated to 300 to 400 ° C in a furnace, the cellulose fibers are blackened by this chemical. Therefore, a white coating layer appeared in contrast to the black substrate, and this uniformity was sensory evaluated. The evaluation criteria are shown below. However, in the present invention, the object of the invention is ○ or more.
◎ (very good): The white coating layer is almost completely uniform. ○ (good): Some black fiber parts are observed, but the whole is uniform. △ (normal): Black fiber parts are about 1/3 of the total area. Occupancy, partially non-uniform × (defect): Black fiber part occupies more than half of the total area, and the entire surface is non-uniform

(2) Printing unevenness The printing unevenness in the coated paper for printing produced by performing monochromatic printing using an RI printing aptitude tester was visually observed. The evaluation criteria are shown below. However, in the present invention, the object of the invention is ○ or more.
A (very good): No printing unevenness is observed.
○ (Good): Print unevenness is observed only slightly, but the product is good.
Δ (Normal): Printing unevenness is observed, but it is acceptable as a product.
X (defect): Printing unevenness was observed and the product could not be used.

(3) Coating surface quality The coating surface after passing through the blade during coating was irradiated with fluorescent light at an angle of 75 degrees to visually evaluate the coating surface quality. The evaluation criteria are shown below. However, in the present invention, the object of the invention is ○ or more.
A (very good): The reflected light on the coated surface is uniform.
○ (Good): Very slight variation is observed in the reflected light of the coated surface.
Δ (Normal): Reflected light on the coated surface slightly fluctuates, and very fine streaks are observed.
X (defect): Reflected light on the coated surface fluctuates significantly and clear streaks are observed.

(4) Thermal deformation of the blade tip After replacing the blade with a new blade, the contact surface with the web at the blade tip is magnified 20 times with a microscope, and the state of thermal deformation is visually observed. evaluated. The evaluation criteria are shown below. However, in the present invention, ◯ Δ to Δ or more are the objects of the invention.
A (very good): No thermal deformation is observed at all.
○ (Good): Slight deformation is observed.
○ △ (good): Slight deformation is observed in a small part.
○ Δ to Δ (slightly good): Slight deformation is observed throughout.
Δ (Normal): Slight deformation is observed on the entire surface, and clear deformation is observed in part.
X (defect): Clear deformation is recognized on the entire surface.

(5) Out-of-paper occurrence status The frequency of occurrence of out-of-paper due to blade factors when the start of printing is stopped and the old base paper roll being applied and the starting end of the new base paper roll are spliced in the running state. The evaluation criteria are shown below. However, in the present invention, the object of the invention is ○ or more.
A (very good): No paper breakage occurs.
○ (Good): Paper breakage occurs about once in 20 to 50 times of the above operation.
Δ (Normal): Paper breakage occurs about once out of the above operations 10 to 20.
X (Bad): Paper breakage occurs about once out of the above operations 1 to 10.

  The present invention has good and stable image reproducibility because the coated paper has a uniform base paper coverage, so that it is a coated paper for printing, white paperboard, electrophotographic recording paper, inkjet paper, thermal paper, It can be used for coated paper such as pressure paper.

The conceptual diagram which supplies a liquid to the contact part of the web just before a blade front-end | tip part contacts in a blade coater, or a front-end | tip part and a web.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blade base material 2 Tip part 3 Web 4 Backing roll 5 Fountain applicator 6 Coating liquid 7 Clamp 8 Mist shower device 9, 10, 11 Mist shower 12 Liquid tank 13 Air compressor

Claims (5)

  In a method for producing a coated paper in which a coating liquid is supplied onto a traveling web and then applied to a desired coating amount by a coating blade, 50 to 50 Shore A is used to scrape the coating liquid in contact with the web. Using a coating blade composed of a tip portion having a hardness of 100 and a blade base material made of a material different from the tip portion, which urges the tip portion to the web, When splicing the base paper roll and the base paper start end of the new base paper roll in the running state, while the tip is in contact with the web in a state where no coating liquid is being supplied to the web, immediately before the tip comes into contact A method for producing a coated paper, characterized in that a liquid is supplied to a web or a contact portion between the tip and the web, and cooled or lubricated.   2. The method for producing coated paper according to claim 1, wherein the method for adhering the liquid comprises spraying the liquid with a mist shower.   The method for producing a coated paper according to claim 1 or 2, wherein the liquid is 5 to 100 mPa · s in a Brookfield viscometer described in JIS Z8803.   The temperature of the said liquid is 20 degrees C or less, The manufacturing method of the coated paper in any one of Claims 1-3 characterized by the above-mentioned.   The said liquid contains a lubricant, The manufacturing method of the coated paper in any one of Claims 1-4 characterized by the above-mentioned.

Images