JP2006161192A - Bulking paper and method for producing bulking paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing bulking paper by which yield of a bulking agent is raised and staining or formation of foam in a papermaking system can be reduced with good operation efficiency and to provide the bulking paper having smaller deterioration of paper strength as compared with that of paper produced by a conventional method for internal addition of the bulking agent. <P>SOLUTION: The method for producing the bulking paper is carried out as follows. A slurry of pulp fibers is mixed with an aqueous dispersion of the bulking agent for papermaking to thereby carry out a treatment of filling internal voids of the pulp fibers with bulking agent particles. The resultant paper stock containing the mixture liquid is then formed into a sheet of paper and dried to produce the bulking paper. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bulky paper containing a bulking agent for papermaking and a method for producing the bulky paper. More specifically, the present invention relates to a method for producing a bulky paper having a high bulking agent yield and capable of reducing the occurrence of papermaking stains and bubbles, and having good operability. The present invention relates to a bulky paper in which the paper strength is less reduced than that of paper.

  Comic books and paperbacks have rapidly spread, reflecting the recent separation of print. Along with this, paper is also required to be lighter. Here, the weight reduction of paper refers to weight reduction while maintaining the thickness of the paper, that is, increase in bulk (reduction in density). Now that environmental problems are being sought, paper weight reduction is an unavoidable problem in making effective use of paper pulp made from forest resources.

  As a conventional technique for making paper bulky, there is a technique for producing a bulky paper by internally adding a surfactant-based or non-surfactant-based bulking agent, which has been widely used in recent years.

  In the method using a surfactant, for example, a paper bulking agent containing a specific alcohol and / or a polyoxyalkylene adduct thereof is disclosed (see Patent Document 1). There is also a method using a nonionic surfactant (see Patent Document 2). Further, a paper bulking agent composed of a polyhydric alcohol and a fatty acid ester compound (see Patent Document 3) is disclosed, and there is a technique in which this paper bulking agent is applied to paperboard (see Patent Document 4). In the case of a bulking agent containing these surfactants, the generation of bubbles in the papermaking system due to the surfactant is a problem.

  Further, as a technique for a non-surfactant bulking agent, for example, a bulking agent for paper containing at least one compound selected from a cationic compound having a specific structure, an amine, an acid salt of an amine and an amphoteric compound. Is disclosed (see Patent Document 5). There are also fatty acid polyamide polyamine type bulking agents.

  When these bulking agents are added internally, since the one-pass yield on the wire of the bulking agent is low, the bulking agent that has passed through the wire gradually accumulates in the papermaking system, and the concentration of the bulking agent in the paper machine inlet or white water is low. Due to the increase, the generation of dirt and bubbles in the papermaking system has been a problem. In addition, the stain has been transferred to the product, the surface smoothness of the paper is impaired, and in severe cases, the paper may be cut, resulting in a problem that the productivity is significantly reduced.

  In general, the internally added paper chemical is easily fixed on fine fibers having a large specific surface area, and the yield of the internally added paper chemical can be improved by increasing the yield of the fine fibers. From this point of view, measures have been taken to improve the yield of papermaking chemicals by increasing the amount of inorganic coagulants such as sulfuric acid bands and yield improvers of various components. However, in the case of a bulking agent, the fixing strength of the bulking agent to the fine fibers is very weak and reversible adsorption. Therefore, it is difficult to improve the yield of the bulking agent even if these measures are taken. The development of a technique for improving the yield of the agent has been eagerly desired.

  Further, in the conventional internal addition method in which the aqueous dispersion of the bulking agent is simply added to the pulp fiber slurry, it is considered that most of the added bulking agent is attached to the outer surface of the pulp fiber. The presence of the adhering bulking agent inhibits hydrogen bonding between pulp fibers and achieves paper bulking (low density), but on the other hand, as a result of hindering hydrogen bonding, the strength of the paper decreases. There was a problem that. Thus, establishment of a technique for using a bulking agent that hardly reduces paper strength has been desired.

International Publication No. 98/03730 Pamphlet JP 11-200283 A Japanese Patent No. 2971447 Japanese Patent No. 3041294 JP 11-269799 A

  The problem to be solved by the present invention is to firstly provide a method for producing a bulky paper that can increase the yield of the bulking agent and reduce the occurrence of papermaking stains and bubbles, and has good operability. Secondly, the present invention is to provide a bulky paper with less reduction in paper strength as compared with a paper produced by a conventional internal addition method of a bulking agent.

  After the pulp fiber slurry and the aqueous dispersion of the bulking agent for papermaking are mixed, the bulking agent particles are filled into the internal voids of the pulp fiber, and then the paper stock containing the mixed liquid is made into paper and dried. , Producing bulky paper.

  According to the method for producing bulky paper of the present invention, the one-pass yield on the wire of the bulking agent is improved, the generation of dirt and bubbles in the papermaking system is reduced, and the operability is improved. In addition, the bulky paper produced by the method for producing bulky paper of the present invention is less deteriorated in paper strength than the bulky paper produced by the conventional internal addition method of the bulking agent.

  The bulky paper manufacturing method according to the first invention will be described. The bulking agent for papermaking used in the present invention is one in which the pulp fiber slurry and the aqueous dispersion of the bulking agent for papermaking are mixed under specific conditions so that the bulking agent particles are filled in the internal voids of the pulp fiber. It needs to be in the form of particles, and is selected from known bulking agents for papermaking. The average particle diameter of the bulking agent by the laser diffraction scattering method is preferably from 0.01 to 50 μm, more preferably from 0.01 to 20 μm. It can be used regardless of the chemical component or surface charge of the bulking agent. As the result of the particles of the bulking agent for paper making entering the internal voids of the pulp fiber, the pulp fiber is less dropped during dehydration on the wire. The generation of dirt and bubbles can be reduced. Since the surfactant-based bulking agent is in the form of a solution, the effect of the present invention cannot be obtained.

  Examples of such bulking agents include esterified products of saturated fatty acids with polyhydric alcohols (for example, Kao Corporation, KB110, KB115, etc.), saturated fatty acid amides, unsaturated fatty acid amides (for example, Nippon Oil & Fats Co., Ltd., DZ2200 Etc.), alcohol polyethylene oxide adducts (for example, KB08W manufactured by Kao Corporation) and the like.

  Details of the esterified product of a saturated fatty acid with a polyhydric alcohol are as follows. The polyhydric alcohol of the fatty acid ester (a) of the polyhydric alcohol constituting the bulking agent for paper is preferably a 2-14 polyhydric alcohol having a total carbon number of 2-24, which may contain an ether group. As the dihydric alcohol, those having a total carbon number of 2 to 10 which may contain an ether group, for example, propylene glycol, dipropylene glycol, butylene glycol, dibutylene glycol, ethylene glycol, diethylene glycol, polyethylene glycol are trivalent or more. As the alcohol, an alcohol having a total carbon number of 3 to 24 which may have an ether, a total number of hydroxyl groups / total number of carbons in one molecule = 0.4 to 1, for example, glycerin, poly (n = 2 -5) Glycerin, pentaerythritol, dipentaerythritol, arabitol, sorbitol, stachyose, erythritol, arabit, mannitol, glucose, sucrose and the like. Preferably, ethylene glycol, diethylene glycol, propylene glycol, an alcohol having 3 to 12 total carbon atoms which may have an ether group, and a trivalent or higher alcohol in which the number of hydroxyl groups in one molecule / total number of carbons = 0.5 to 1 It is. More preferred are glycerin, poly (n = 2-4) glycerin, and pentaerythritol.

  The fatty acid constituting the fatty acid ester (a) of the polyhydric alcohol includes fatty acids having 1 to 24 carbon atoms, preferably 10 to 22 carbon atoms, and may be any of saturated, unsaturated, straight chain, and branched chain. Particularly preferred are linear saturated fatty acids. More preferred are lauric acid, stearic acid, palmitic acid, oleic acid, myristic acid and behenic acid.

  The fatty acid ester (a) of a polyhydric alcohol can be obtained by performing a conventionally known esterification reaction and alkylene oxide addition reaction. For example, an esterification catalyst is added to a mixture of fatty acid and polyhydric alcohol, and an ester compound is obtained by reacting at 150 to 250 ° C. Further, alkylene oxide is added in the presence of an alkali catalyst or the like. , An alkylene oxide adduct is obtained. Moreover, you may esterify after adding an alkylene oxide to a fatty acid or a polyhydric alcohol. Further, it may be obtained by adding only an alkylene oxide to a fatty acid.

  The average ester substitution degree of the fatty acid ester (a) of the polyhydric alcohol is greater than 0, preferably 10 to 95 equivalent% of OH in the alcohol per 1 mol of polyhydric alcohol, particularly 1 Those having 1 to 2 moles of fatty acid groups per mole of polyhydric alcohol.

  The fatty acid ester (a) of the polyhydric alcohol has an HLB in the range of 1 to 14, preferably 1.5 to 10, and more preferably 2.5 to 6. The melting point is 100 ° C. or lower, preferably −15 ° C. or higher and 80 ° C. or lower, more preferably 20 ° C. or higher and 70 ° C. or lower.

  As the surfactant (b), known ones can be used and are nonionic, anionic, cationic, polymer, preferably nonionic surfactants.

  The ratio between the fatty acid ester (a) of the polyhydric alcohol and the surfactant (b) is (a) / (b) = 99.5 / 0.5 to 70/30 (weight ratio), preferably 98/2 to 80/20 It is.

  The solid content concentration of the aqueous dispersion of the bulking agent for papermaking is 0.1 to 30% by weight. The solid content addition amount of the bulking agent for papermaking relative to the stock is determined by the target value of the density (bulk height) of the bulky paper to be produced, but usually 0.1 to 25 solids weight relative to the absolute dry weight of the pulp %, And more preferably 0.1 to 10% by weight solids.

  The apparatus used for filling the bulking agent particles in the internal voids of the pulp fibers can sufficiently mix both liquids with a strong stirring force, and can fill the bulking agent particles in the internal voids of the pulp fibers by mixing for a predetermined time. There is no particular limitation as long as it is a thing. As such an apparatus, it is possible to use various pulpers and disintegrators that are used to disperse and disperse waste paper, waste paper, dry pulp, wet pulp, and the like in water to produce pulp fiber slurry. There are two types of disintegrators, a horizontal type with an impeller that performs disaggregation, and a vertical type with a bottom, but this is not distinguished and can be used in the present invention. Moreover, although there exist a batch type and a continuous type in a disaggregator, the thing of any system can be used if the mixing processing time mentioned later can be ensured. In addition, pulp and disintegrators are for low concentrations (about 1-6% in pulp solids concentration), for medium concentrations (about 7-10% in pulp solids concentration), for high concentrations (about 12 in pulp solids concentration) ˜22%), any of which can be used in the present invention. Therefore, the solid content concentration of the pulp fiber slurry is in the range of 1 to 22%. However, it is desirable that the pulp concentration be as high as possible because the higher the pulp concentration, the more efficiently the bulking agent particles can be filled into the pulp fiber voids, and the higher the pulp concentration, the smaller the scale of the processing apparatus.

  The appropriate mixing time of the pulp fiber slurry and the bulking agent aqueous dispersion is influenced by the solid content concentration of the pulp fiber and the mixing ability of the disintegrator, and is generally unclear, but is usually in the range of 5 to 60 minutes. . It is preferably 10 to 45 minutes, more preferably 10 to 30 minutes. When the mixing treatment time is less than 5 minutes, the bulking agent particles are not sufficiently filled in the internal voids of the pulp fiber, and the yielding effect of the bulking agent, which is the effect of the present invention, the low density effect of the paper, and the paper Less effective in reducing strength. If it exceeds 60 minutes, the scale of the apparatus used for the mixing process becomes too large, which is not practical.

  The raw material pulp of the bulky paper produced in the present invention may be any pulp that is usually used for paper, and is not particularly limited. Chemical pulp (CP), groundwood pulp (GP), chemiground pulp (CGP), Refiner ground pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), pulp of various production methods such as semi-chemical pulp (SCP), and these softwood, hardwood pulp, bleached, unbleached Pulp and pulp obtained by appropriately blending deinked pulp (DIP) or the like according to the type of paper. As one of the effects of the present invention, by filling many bulking agent particles in the internal voids of the pulp fibers, hydrogen bonding in the pulp fiber internal voids is inhibited, and the degree of flattening of the pulp fibers is reduced, It is thought that the density of the paper is reduced accordingly. From this point of view, it is considered that the pulp fiber mixed with the bulking agent aqueous dispersion is more effective in reducing the density of the paper when the fiber is relatively soft. The more lignin that remains in the pulp, the stiffer the pulp fibers. Therefore, chemical pulp is preferable to ground pulp (GP) and mechanical pulp (MP). Also, bleached pulp is preferred over unbleached pulp.

  The pulp to be mixed with the bulking agent aqueous dispersion may be used for all pulp raw materials supplied to the paper machine, or a part thereof may be mixed.

  In order to process the whole pulp raw material, it is necessary to process continuously, and the following three types are considered. The first method is a case in which the raw material residence time in a mixer conventionally used for mixing various pulps satisfies the mixing treatment time of 5 to 60 minutes, and the mixer is placed in the internal voids of the pulp fiber. It can be set as the mixing processing apparatus for filling a bulking agent particle. The second method is a case where the raw material residence time in the mixer conventionally used for mixing various pulps is less than 5 minutes, which is the shortest time of the mixing process, and in this case, immediately after the mixer. A mixing treatment apparatus is installed, and the residence time of the raw material pulp in both apparatuses is set to 5 to 60 minutes. Moreover, the raw material residence time in the mixing processing apparatus installed immediately after the mixer can be set to 5 to 60 minutes.

  There are two methods for mixing a part of the pulp raw material supplied to the paper machine. One is a method in which only chemical pulp and / or bleached pulp having relatively soft fibers are mixed with a bulking agent aqueous dispersion. In this method, the mixing treatment apparatus is preferably installed in front of a mixer conventionally used for mixing various pulps, and the pulp fiber slurry that has been treated in the mixing apparatus is added to the mixer. Another method is a method in which a part of the mixed pulp after the mixer is extracted and mixed with the bulking agent aqueous dispersion. In this method, the mixing treatment apparatus is installed immediately after the mixer, and the raw material residence time in the mixing treatment apparatus needs to be 5 to 60 minutes. The pulp fiber slurry that has been processed by the mixing device is returned to the raw material supply line to the paper machine head box downstream from the mixer. When a part of the pulp raw material is mixed and processed, it can be used after temporarily storing the slurry of pulp fibers that has been processed by the mixing device, or can be added and used continuously.

  The paper to which the bulky paper production method of the present invention is applied is a paper produced by an acid papermaking, neutral papermaking or alkaline papermaking method. There are no limitations on the type of paper, newsprint, printing / information paper (advanced, intermediate, lower grade, non-coated printing paper such as thin leaf printing paper, special quality printing paper such as high quality, postcard paper, copying paper, and photosensitive paper. Paper, foam paper, PPC paper, information recording paper, etc.), packaging paper, paperboard, various base papers (coating base paper, fine coating base paper, lightweight coating base paper, inkjet recording base paper, etc.) It can also be applied to other papers. Among these, it can be suitably applied to book paper, magazine paper, and the like that are particularly required to be bulky.

  If necessary depending on the type of paper, known internally added neutral sizing agents can be used, from alkyl ketene dimer (AKD) sizing agents, alkenyl succinic anhydride (ASA) sizing agents, and neutral rosin sizing agents. At least one sizing agent selected is used. Further, as a filler, in addition to light calcium carbonate, heavy calcium carbonate, magnesium carbonate, barium carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, as long as the bulkiness of the bulky paper of the present invention is not impaired. 1 selected from inorganic fillers such as zinc hydroxide, clay, calcined kaolin, deramikaolin, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, urea-holimarin resin, polystyrene resin, phenol resin, fine hollow particles, etc. More than one type can be used in combination.

  In the bulky paper manufacturing method of the present invention, various conventionally used nonionic and cationic retention agents, freeness improvers, paper strength improvers, and the like are used as necessary for papermaking. It is appropriately selected and used. Further, for example, sulfuric acid bands, aluminum chloride, sodium aluminate, basic aluminum compounds such as basic aluminum chloride and basic polyaluminum hydroxide, water-soluble aluminum compounds such as water-degradable alumina sol, sulfuric acid A polyvalent metal compound such as ferrous sulfate or ferric sulfate, silica sol, or the like may be internally added. Other starches for papermaking, various starches, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic cross-linked polymer Various compounds such as particle dispersions and derivatives or modified products thereof can be used. Furthermore, internal additives for papermaking such as dyes, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added depending on the intended use.

  The type of the paper machine is not particularly limited, and can be appropriately made with a long paper machine, a twin wire machine, a Yankee paper machine, or the like. The press line pressure is used within the normal operating range. The surface treatment agent may or may not be applied. When applying the surface treatment agent, the size press type is not limited, and a liquid roll transfer type size press such as a 2-roll size press, a gate roll size press, or a shim sizer can be appropriately used. The calender is used at a linear pressure within the normal operating range, but from the viewpoint of producing bulky paper, a low linear pressure or bypass is preferred as long as the smoothness of the paper can be maintained, and moreover than a normal calender. A soft calendar is preferred.

  The type of surface treatment agent used when applying the surface treatment agent is not particularly limited. For example, raw starch, oxidized starch, esterified starch, cationized starch, enzyme-modified starch, aldehyde-modified starch, hydroxyethylated Modified starches such as starch, cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, modified alcohols such as polyvinyl alcohol and carboxyl-modified polyvinyl alcohol, styrene butadiene copolymers, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, poly Vinyl chloride, polyvinylidene chloride, polyacrylic acid ester, polyacrylamide and the like can be used alone or in combination. Among them, the application of hydroxyethylated starch, which is excellent in the effect of improving the surface strength, is most preferable. In addition to the above-mentioned agents, surface sizing agents such as styrene acrylic acid, styrene maleic acid, olefinic compounds, and cationic sizing agents can be applied to the surface treatment agent. Further, the coating amount of the surface treatment agent is not particularly limited, and the coating amount is appropriately determined according to the surface strength and size properties required for the bulky paper to be produced.

  In the method for producing bulky paper of the present invention, the bulking agent is filled in the internal voids of the pulp fiber, so that the bulking agent is difficult to be detached during dehydration on the paper machine wire, and the one-pass yield of the bulking agent is increased. As an effect, it is possible to reduce the contamination and foaming of the paper machine white water system by improving the bulking agent one-pass yield.

  The bulky paper as the second invention will be described. In the conventional internal addition method in which the aqueous dispersion of the bulking agent is simply added to the pulp fiber slurry, it is considered that most of the added bulking agent is attached to the surface of the fibrils outside the pulp fiber. Due to the presence of the adhering bulking agent, hydrogen bonding of fibrils of pulp fibers is inhibited, binding of pulp fibers is inhibited, and paper bulking (low density) is achieved. On the other hand, hydrogen bonding is inhibited. As a result, there is a problem that the strength of the paper is lowered. Compared to the bulky paper produced by the conventional internal addition method of such a bulking agent, the bulky paper produced by the method for producing bulky paper according to the first aspect of the invention is that most of the bulking agent particles are made of pulp fibers. As a result of being present in the internal voids, flattening of pulp fibers is inhibited and paper density reduction is achieved, but inhibition of hydrogen bonding of pulp fiber fibrils or inhibition of binding between pulp fibers is alleviated, It has the effect that a decrease in paper strength is suppressed.

Hereinafter, the present invention will be specifically described, but the present invention is not limited to these examples. The parts in the following examples are based on weight unless otherwise specified.
1. Paper bulking agent tested
(1) Mixture of fatty acid ester of polyhydric alcohol and surfactant: KB115 (manufactured by Kao Corporation), average particle diameter of 5.5 μm by laser diffraction scattering method.
2. Other test materials
(1) Base paper pulp: LBKP (CSF400ml)
(2) Cationized starch: CATO315 (made by NSC Japan)
(3) Internal sizing agent: AD1604 (manufactured by Seiko PMC Corporation)
(4) PAM paper strength agent: DS403 (manufactured by Seiko PMC Corporation)
(5) Filler: Light calcium carbonate A (Agglomerated spindle-shaped primary particles, average particle size 3.2 μm, manufactured by Nippon Paper Industries Co., Ltd.)
(6) Yield improver: NR-11LS (made by Hymo Co., Ltd.), FA230 (made by Hymo Co., Ltd.)
5. How to create handmade paper
After adding predetermined amounts of various chemicals to LBKP, the solid content concentration was adjusted to 0.5%. A handmade paper was prepared in accordance with JIS P 8209 except that wet paper was prepared without pressing and then dried with a cylinder dryer.
6). Measuring paper quality
(1) Basis weight: Measured according to JIS P 8124.
(2) Paper thickness: Measured according to JIS P 8118.
(3) Density: Measured according to JIS P 81118.
(4) Ash content: Measured according to JIS P 8251.
(5) Opacity: Measured according to JIS P 8138.
(6) Whiteness: Measured according to JIS P 8148.
(7) Breaking length: Measured according to JIS P8113.
(8) Bulkiness ratio: 100 × (Blank density−Bulk paper density) / Blank density Blank density: The density of 0.485 in Comparative Example 1 was used as a blank.
7). Measurement of bulking agent in handmade paper Quantification was performed by online methylation pyrolysis gas chromatography (manufactured by HEWLETT PACKARD, model HP6890 GC System). The conditions of pyrolysis gas chromatography are as follows.
conditions:
Initial 50 ° C hold 3.0 min
1st stage Heating rate 8.0 ℃ / min 280 ℃ Hold 0.0 min
2nd stage Heating rate 20.0 ℃ / min 320 ℃ Hold 6.0 min
Completed sample weight: about 0.5 μg.

[Example 1]
Bulking agent KB115 is added to 2000 ml of LBKP pulp slurry for papermaking with a solid content concentration of 2%, and 1 wt% of LBKP absolute dry weight is added. And mixed for 10 minutes at 2000 rpm. After the mixing treatment, LBKP was completely dry weighted under low speed stirring with a stirrer, 0.5% sulfuric acid band, 0.8% cationized starch CATO315, 0.2% AKD sizing agent AD1604, and PAM paper strength agent DS403. A light calcium carbonate slurry was sequentially added with a target of 0.2% and a paper filler rate (ash content) of 20%, and then a yield improver (brand: NR-11LS and FA230) was added in an amount of 0.01% to prepare a paper stock. Handmade paper was made from this stock. The paper quality of this handmade paper and the amount of bulking agent in the paper were measured. The results are shown in Table 1.

[Example 2]
Bulking agent KB115 is added to 2000 ml of LBKP pulp slurry for papermaking with a solid content concentration of 2%, and 2 wt% of LBKP absolute dry weight is added. And mixed for 10 minutes at 2000 rpm. After the mixing treatment, LBKP was completely dry weighted under low speed stirring with a stirrer, 0.5% sulfuric acid band, 0.8% cationized starch CATO315, 0.2% AKD sizing agent AD1604, and PAM paper strength agent DS403. A light calcium carbonate slurry was sequentially added with a target of 0.2% and a paper filler rate (ash content) of 20%, and then a yield improver (brand: NR-11LS and FA230) was added in an amount of 0.01% to prepare a paper stock. Handmade paper was made from this stock. The paper quality of this handmade paper and the amount of bulking agent in the paper were measured. The results are shown in Table 1.

[Example 3]
Bulking agent KB115 is added to 2000 ml of LBKP pulp slurry for papermaking with a solid content concentration of 2%, and 1 wt% of LBKP absolute dry weight is added. And mixed for 30 minutes at 2000 rpm. After the mixing treatment, LBKP was completely dry weighted under low speed stirring with a stirrer, 0.5% sulfuric acid band, 0.8% cationized starch CATO315, 0.2% AKD sizing agent AD1604, and PAM paper strength agent DS403. A light calcium carbonate slurry was sequentially added with a target of 0.2% and a paper filler rate (ash content) of 20%, and then a yield improver (brand: NR-11LS and FA230) was added in an amount of 0.01% to prepare a paper stock. Handmade paper was made from this stock. The paper quality of this handmade paper and the amount of bulking agent in the paper were measured. The results are shown in Table 1.

[Example 4]
Bulking agent KB115 is added to 2000 ml of LBKP pulp slurry for paper making with a solid content concentration of 2%, 2 wt% of LBKP absolute dry weight, and TAPPI disintegrator (KUMAGAI RIKI KOGYO Co., LTD. Was mixed for 30 minutes at 2000 rpm. After the mixing treatment, LBKP was completely dry weighted under low speed stirring with a stirrer, 0.5% sulfuric acid band, 0.8% cationized starch CATO315, 0.2% AKD sizing agent AD1604, and PAM paper strength agent DS403. A light calcium carbonate slurry was sequentially added with a target of 0.2% and a paper filler rate (ash content) of 20%, and then a yield improver (brand: NR-11LS and FA230) was added in an amount of 0.01% to prepare a paper stock. Handmade paper was made from this stock. The paper quality of this handmade paper and the amount of bulking agent in the paper were measured. The results are shown in Table 1.

[Comparative Example 1]
LBKP absolute dry weight, 0.5% sulfuric acid band, 0.8% cationized starch CATO315, 0.2% AKD sizing agent AD1604, 0.2% PAM-based paper strength agent DS403, with a low agitation with a stirrer (Ash content) Light calcium carbonate slurry was sequentially added with a target of 20%, and then a yield improver (brand: NR-11LS and FA230) was added in an amount of 0.01% to prepare a paper stock. Handmade paper was made from this stock. The paper quality of this handmade paper and the amount of bulking agent in the paper were measured. The results are shown in Table 1.

[Comparative Example 2]
Under the LBKP absolute dry weight, 0.5% sulfuric acid band, 0.8% cationized starch CATO315, 0.2% AKD sizing agent AD1604, 0.2% PAM paper strength agent DS403, and bulking agent KB115 A light calcium carbonate slurry was sequentially added with a target of 1% and a filler content in paper (ash content) of 20%, and then a yield improver (brand: NR-11LS and FA230) was added in an amount of 0.01% to prepare a paper stock. Handmade paper was made from this stock. The paper quality of this handmade paper and the amount of bulking agent in the paper were measured. The results are shown in Table 1.

[Comparative Example 3]
Under the LBKP absolute dry weight, 0.5% sulfuric acid band, 0.8% cationized starch CATO315, 0.2% AKD sizing agent AD1604, 0.2% PAM paper strength agent DS403, and bulking agent KB115 A light calcium carbonate slurry was sequentially added with a target of 2% and a filler content (ash content) of 20%, and then a yield improver (brand: NR-11LS and FA230) was added in an amount of 0.01% to prepare a paper stock. Handmade paper was made from this stock. The paper quality of this handmade paper and the amount of bulking agent in the paper were measured. The results are shown in Table 1.

  From the results shown in Table 1, the relationship between the bulk ratio of the handmade paper and the breaking length is shown in FIG. 2, and the relationship between the density of the handmade paper and the breaking length is shown in FIG.

  The following can be understood from the results in Table 1. From the comparison between Examples 1 and 3 and Comparative Example 1 and from the comparison between Examples 2 and 4 and Comparative Example 3, the pulp dispersion for paper and the aqueous dispersion of the bulking agent for papermaking were mixed with a disintegrator. In the example, it can be seen that the amount of bulking agent in the paper is greatly increased, and the one-pass yield of the bulking agent is increased, and as a result, the density of the paper is decreased despite the same bulking agent addition rate. In addition, by increasing the mixing treatment time in the disaggregator, the amount of bulking agent in the paper is increased and the one-pass yield of the bulking agent is increased. It can be seen that the density decreases. Since the one-pass yield of the bulking agent is dramatically increased by the method for producing bulky paper of the present invention, the bulking agent can be used efficiently. Therefore, in the bulky paper production method of the present invention, compared with the conventional production method in which the bulking agent is simply added to the stock, the bulky paper produced is lower when the bulking agent addition rate is constant. Become density. Alternatively, when the target density is constant, the amount of bulking agent added can be reduced. Furthermore, accumulation of the bulking agent in the papermaking system is reduced, dirt and foaming in the papermaking system can be reduced, and operability is improved.

  FIG. 1 shows the bulk ratio of the paper obtained in Examples 1 to 4 and Comparative Examples 2 and 3 on the basis of the density of the paper obtained in Comparative Example 1, and the relationship between the bulk ratio and the breaking length Plotted by untreated (Comparative Examples 2 and 3), 10 minutes (Examples 1 and 2), and 30 minutes (Examples 3 and 4) according to the mixing treatment time by the disaggregator. From the result of FIG. 1, it can be seen that the longer the mixing treatment time by the disaggregator, the higher the breaking length compared with the same bulkiness factor. FIG. 2 shows the relationship between the density of the paper and the breaking length, untreated (Comparative Examples 2 and 3), 10 minutes (Examples 1 and 2), 30 minutes (Example 3, This is plotted in 4). From the results of FIG. 2, it can be seen that the longer the mixing treatment time by the disaggregator, the higher the breaking length compared with the same density. From the results shown in FIGS. 1 and 2, the bulky paper produced by the method for producing bulky paper of the present invention is a paper that is compared with the bulky paper produced by a conventional production method in which a bulking agent is simply added to the stock. It can be seen that the paper strength is high because the decrease in force is suppressed.

FIG. 4 is a relationship diagram between the bulk ratio of handmade paper and the breaking length. FIG. 4 is a relationship diagram between the density of the handmade paper and the breaking length.

Claims (2)

  A method for producing a bulky paper containing at least pulp fiber and a paper bulking agent, wherein the bulking agent particles are mixed in the internal voids of the pulp fiber by mixing a slurry of pulp fiber and an aqueous dispersion of the paper bulking agent. A method for producing a bulky paper, characterized in that after the treatment of filling the paper, the paper stock containing the mixed solution is made and dried. A bulk paper containing at least pulp fibers and a bulking agent for paper, and by mixing a slurry of pulp fibers and an aqueous dispersion of the bulking agent for papermaking, the bulking agent particles are filled in the internal voids of the pulp fiber. Bulky paper produced by papermaking and drying the paper stock containing the mixed solution after the treatment.

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