JP2006152509A - Method for producing bulky pulp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing papermaking pulp that does not impair printability and has not only excellent bulkiness but also fading characteristics when made into paper. <P>SOLUTION: The method for producing bulky pulp comprises mixing a bleached chemical pulp slurry with an interfiber bonding inhibitor, heating the slurry to the melting point of the interfiber bonding inhibitor and drying the heated slurry. Preferably the Canadian Standard Freeness (CSF) of the bleached chemical pulp slurry is adjusted to ≥300 mL and ≤600 mL, the slurry is mixed with an interfiber bonding inhibitor, heated to the melting point of the interfiber bonding inhibitor and dried. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a paper pulp having excellent bulkiness and improved fading.

  Paper is required to be lighter from the viewpoint of saving resources and logistics costs, and from social demands such as an increase in environmental protection movement. However, when the paper is lightened, the paper thickness decreases, and as a printed matter, the opacity decreases and the printing on the back side becomes transparent, which not only makes it difficult to read, but also impairs the high-quality paper. There is a demand for weight reduction, that is, bulkiness while maintaining the above.

  As a method for increasing the bulk of paper, firstly, the study of wood pulp, which is the main raw material of paper, is raised. Mechanical pulp such as thermo-pulverized pulp obtained by pulverizing wood with a grinder or thermo-mechanical pulp obtained by defibrating wood with a refiner is effective in increasing the bulk of paper because the fibers are rigid. The contribution to conversion is great. However, since mechanical pulp contains a large amount of lignin, the discoloration over time is large, and the blending amount is limited. In particular, in the case of high-quality paper, blending of mechanical pulp is difficult due to problems in specifications.

  Chemically bleached pulp is used for fine paper. The density of the paper is greatly influenced by the raw material tree species used for the chemically bleached pulp, and the coarser the wood fibers themselves, the more bulky paper is obtained. Japanese Patent Laid-Open No. 10-204790 (Patent Document 1) discloses a method for producing a low-density book paper having excellent flexibility by containing 50 to 100% by weight of dipterocarp pulp in LBKP. Yes. However, it is virtually difficult to select and pulp specific tree species as current environmental protection movements grow.

  Usually, paper pulp is subjected to a beating process to make paper. By refining and shortening the pulp fibers by beating, the strength when made into paper is increased, and smoothness and uniformity (texture) are imparted. However, since the volume tends to decrease due to the beating process, it is preferable to suppress the beating process in order to increase the bulk. However, if the beating process is insufficient, the strength and smoothness of the paper are reduced.

  As a technique for increasing the bulk using pulp other than wood pulp, Japanese Patent Laid-Open No. 2003-278091 (Patent Document 2) discloses a method of blending lyocell, which is a regenerated cellulose fiber, into paper. Patent Document 3) discloses a method of using synthetic pulp crimped three-dimensionally. However, since these pulps are significantly more expensive than wood pulp, it is difficult to apply them to versatile printing paper.

  Studies are also being conducted to improve the bulkiness when paper is made by applying an additional treatment to paper pulp. Japanese Patent Application Laid-Open No. 4-185792 (Patent Document 4) discloses a technique of increasing the bulk by using a defibrated pulp after crosslinking with a crosslinking agent. However, printing paper is used to reduce pulp recyclability. It is difficult to use it for highly versatile paper. Japanese Patent Application Laid-Open No. 7-54293 (Patent Document 5) discloses a technique for improving bulkiness by treating pulp with polysaccharide-degrading enzymes such as cellulase and hemicellulase or microorganisms that produce them. However, in this method, the enzyme is expensive and the cost is increased. Japanese Patent Application Laid-Open No. 2002-294582 (Patent Document 6) discloses a technique for improving bulkiness by applying shear stress to pulp under acidic pH of 2 to 4. In this method, it is necessary to adjust the pH after the treatment, and particularly when used for neutral paper, the cost increases due to the use of neutralizing chemicals and washing water.

  Examples of the method for increasing the bulk during papermaking include lowering the pressing pressure in the pressing step and suppressing calendar treatment for imparting smoothness to the paper. However, at present, satisfactory bulkiness cannot be obtained by these methods alone.

  In addition to dealing with such pulp and papermaking, bulking from fillers and chemicals added to papermaking raw materials is also being studied. Examples of the method for increasing the bulk from the filler include a method of blending the bulk filler. Bulky fillers are those that have microporous in filler particles such as amorphous silica, amorphous silicate, zeolite, etc., fillers with a high aspect ratio such as needle-like, columnar, and tiger-like calcium carbonate, and hollow forms. Examples thereof include synthetic organic capsules, which are characterized by small bulk specific gravity of particles. Although bulkiness can be obtained by increasing the blending amount of the bulking filler, there is a problem that increasing the blending amount tends to reduce paper strength and generate paper dust.

In recent years, a technique for increasing the bulk by adding a bulking agent to a papermaking raw material has been performed. As the bulking agent, a surfactant which is a compound having a hydrophilic group and a hydrophobic group is generally used. The bulking agent is fixed to the pulp fiber at the time of papermaking, and the distance between the fibers is increased, thereby increasing the volume of the paper. It is believed that flexibility is imparted. However, when a bulking agent is used during papermaking, the bulking agent not fixed to the pulp fiber causes a problem such as foaming of the papermaking system, so the amount of bulking agent added is limited. Further, in a high speed paper machine with a low yield of papermaking raw materials, the amount of addition must be increased to obtain a sufficient bulkiness effect, and a sufficient bulkiness effect cannot be obtained with a bulking agent alone.
JP-A-10-204790 JP 2003-278091 A JP-A-6-272189 Japanese Patent Laid-Open No. 4-185792 JP 7-54293 A JP 2002-294582 A

  The present invention provides a method for producing paper pulp with excellent bulkiness and improved fading.

As a result of intensive studies in view of the above, the present inventors have invented the method for producing a bulky pulp of the present invention. That is, the present invention is as follows.
(1) A method for producing a bulky pulp, wherein an interfiber bond inhibitor is added and mixed in a bleached chemical pulp slurry, and then heated to a melting point or higher of the interfiber bond inhibitor to dry.

(2) Bring the Canadian standard freeness (CSF) of the bleached chemical pulp slurry to a range of 300 mL to 600 mL and add an interfiber binding inhibitor, and then heat to dry above the melting point of the interfiber binding inhibitor. A method for producing a bulky pulp, characterized in that:

(3) Paper blended with bulky pulp produced by the methods of (1) and (2).

  The present invention provides a method for producing paper pulp with excellent bulkiness and improved fading.

  In the present invention, as a result of diligent investigation, a bleached chemical pulp containing an interfiber bond inhibitor is made up and heated to a temperature equal to or higher than the melting point of the interfiber bond inhibitor to produce a dry pulp sheet. It has been found that a pulp with improved properties can be obtained. In addition, heating to the melting point or higher promotes the coating of the interfiber bond inhibitor onto the pulp fiber, and a part of the bleached chemical pulp has excellent fading properties by partially penetrating into the fiber. It was found that a pulp having a high bulk effect was obtained.

  The interfiber bonding inhibitor used in the present invention is preferably a surfactant having a hydrophobic group and a hydrophilic group in the molecule. Examples include polyhydric alcohol and fatty acid ester compounds, nonionic surfactants, oil-based nonionic surfactants, sugar alcohol-based nonionic surfactants, sugar-based nonionic surfactants, polyhydric alcohol-type non-ionic surfactants. Ionic surfactant, higher alcohol, fatty acid bisamide, condensate of fatty acid and polyvalent amine, polyoxyalkylene adduct of higher alcohol or higher fatty acid, polyoxyalkylene adduct of higher fatty acid ester, ester of polyhydric alcohol and fatty acid Examples include polyoxyalkylene adducts of compounds, fatty acid polyamides, fatty acid polyamide amines, and alkylene oxide oligomers. It is appropriately selected within a range that does not impair the effect of the paper-making chemicals used for making bulky pulp and does not deteriorate the fading property of the paper.

  As bleached chemical pulp used for the bulky pulp of the present invention, unbleached pulp obtained by cooking methods such as kraft cooking method, polysulfide cooking method, sulfite cooking method, etc. using oxygenated lignin After the treatment, it is produced by a multistage bleaching method in which chlorine dioxide, chlorine, caustic soda, hypochlorite, hydrogen peroxide, ozone, sodium dithionite, hydrosulfite and the like are appropriately added. Considering the load of organic chlorine compounds on wastewater, a chlorine-free multi-stage bleaching method in which chlorine dioxide and ozone are first applied as a substitute for chlorine is preferable.

In the present invention, as a result of intensive studies, after adding an interfiber bond inhibitor to a bleached chemical pulp slurry having a Canadian standard freeness (CSF) of 300 mL or more and 600 mL or less, the mixture is heated to the melting point of the interfiber bond inhibitor or higher. It has been found that a larger bulky effect can be obtained by drying. When the CSF exceeds 600 mL, excellent bulkiness cannot be obtained. When the CSF is less than 300 mL, when making a paper by adding a bulky pulp containing an interfiber binding inhibitor and subjected to heat drying treatment In addition, the decrease in drainage is undesirably large.
The freeness of wood pulp is mainly adjusted by the beating process, but as described above, the volume usually decreases as the beating process proceeds. However, the external and internal fibrillation of the fiber is performed by the beating process, so that the fixing of the interfiber binding inhibitor is enhanced, and the coating and penetration of the fiber by the subsequent heat treatment is promoted, so that the bulky effect is excellent. It seems that pulp is obtained.

  When making paper using the bulky pulp of the present invention, depending on the required properties of the paper, bleached chemical pulp made from hardwood or coniferous wood, non-wood made from cocoon, sanju, hemp, kenaf, etc. Wood pulp, deinked pulp made from waste paper, mercerized pulp, curled fiber, synthetic pulp, etc. can be used in combination, but the bulky pulp of the present invention is bulky by blending 50% by mass or more. As well as increasing printability and fading

  In this invention, a filler can be mix | blended as needed. The filler in this case is not particularly limited, but various pigments generally used for fine paper, such as kaolin, calcined kaolin, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, talc, zinc oxide, alumina, Mineral pigments such as magnesium carbonate, magnesium oxide, amorphous silicate, bentonite, zeolite, sericite, smectite, polystyrene resin, urea resin, melamine resin, acrylic resin, vinylidene chloride resin and their micro hollow Examples thereof include organic pigments such as particles.

  In addition to pulp fibers and fillers, the paper stock contains a variety of anionic, nonionic, cationic or amphoteric yield improvers and filters that have been used so far as long as the desired effects of the present invention are not impaired. Various paper-making internal additives such as an aqueous improver, a paper strength enhancer, and an internal sizing agent can be appropriately selected and used as necessary. 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 use of the paper.

  Paper making using the bulky pulp of the present invention is produced by a known paper machine, for example, a long-mesh type, a circular net-type, a short-net type, or a twin-wire type paper machine.

  In the present invention, various surface binders such as starch, polyvinyl alcohol and polyacrylamide, rosin sizing agents, synthetic sizing agents, petroleum resin sizing agents, neutral sizing agents and other surface sizing agents, sodium chloride, sodium sulfate, etc. The conductive agent can be applied or impregnated as long as the desired effects of the present invention are not impaired.

  Since a bulky pulp having improved fading properties can be obtained by the present invention, high-quality printing paper, writing paper, and office paper excellent in bulkiness can be obtained by using this bulky pulp. In particular, when using the pulp of the present invention as a book paper, the Clark stiffness in the cross direction is lowered, the page is easily turned, and the touch feeling is good and the printability is excellent. Further, by using it as a base paper for coating, it can be used for bulky high-quality coated paper.

The present invention will be specifically described below with reference to examples. Of course, the present invention is not limited to these examples. Moreover, unless otherwise indicated, the part and% in an example show a weight part and weight%.
The evaluation methods of various physical properties in Examples and Comparative Examples are as follows.
Melting point: Measured using a differential scanning calorimeter DSC22C (manufactured by Seiko Instruments Inc.).
-Paper density: Measured according to JIS P 8118.
-Whiteness: The whiteness of the pulp was measured according to JIS P 8123.
-Thermo-fading: The resultant paper was faded at 105 ° C for 24 hours, and the PC value was calculated from the whiteness before and after the fading according to the following formula and evaluated.
PC value = {(1−whiteness after fading) ² / (2 × whiteness after fading) − (1−whiteness before fading) ² / (2 × whiteness before fading)} × 100
-Light fading: irradiated with a xenon lamp for 24 hours under conditions of 32 ° C. and 50% relative humidity, and calculated and evaluated the PC value from the whiteness before and after the fading.
Printing strength: Measured using an offset ink T13 with an RI printing machine (manufactured by Meisei Seisakusho), and the result was evaluated and displayed.
A: High in strength, practically satisfactory, and excellent in quality.
: High strength, no problem in practical use.
: Slightly inferior in strength and problematic in practical use.
X: The strength is remarkably inferior, it is a problem in practical use, and the quality is remarkably inferior.

Example 1
A hardwood bleached chemical pulp (LBKP) slurry having a Canadian freeness (CSF) of 600 mL and a whiteness of 82.0% is coated with an interfiber binding inhibitor (trademark: KB115, melting point: 54 ° C., manufactured by Kao). 2 parts were added per 100 parts, and the pulp sheet made using a paper making machine was dried at 90 ° C. to produce a bulky pulp.
Light calcium carbonate (trademark) was added to a pulp slurry containing 50 parts of the above bulky pulp, 50 parts of LBKP with a Canadian standard freeness (CSF) of 400 mL and whiteness of 81.5% (100 parts of dry pulp). : TP121, manufactured by Okutama Kogyo Co., Ltd.) to 15 parts per paper weight, and 1.0 part of starch, 0.05 part of alkyl ketene dimer, and 0.5 part of sulfuric acid band per 100 parts of dry pulp The paper stock added so as to become a paper is made using an on-top type paper machine, and the oxidized starch is 4.0 g / m ² and the surface sizing agent is 0.08 g / m ² by an on-machine size press coater. Thus, a printing paper having a basis weight of 67.8 g / m ² , a density of 0.57 g / cm ³ , and a Oken type smoothness of 15 seconds was obtained.

Example 2
Per-powder 100 parts dry weight of fiber-bonded inhibitor (trademark: KB115, manufactured by Kao) to hardwood bleached chemical pulp (LBKP) slurry with Canadian standard freeness (CSF) of 400 mL and whiteness of 81.5% After adding 2 parts, the pulp sheet made using a paper making machine was dried at 90 ° C. to contain a fiber-fiber binding inhibitor, and a bulky pulp subjected to heat drying treatment was produced.
50 parts of bulky pulp that has been heat-dried by containing the interfiber binding inhibitor, and 400 parts of Canadian standard freeness (CSF) of 400 mL, LBKP with a whiteness of 81.5% (the amount of dry pulp is 100 Part) was made by the same chemical formulation and paper making method as in Example 1, the basis weight was 69.0 g / m ² , the density was 0.58 g / cm ³ , and the Oken smoothness was 15 Got a second printing paper.

Example 3
A hardwood bleached chemical pulp (LBKP) slurry having a Canadian standard freeness (CSF) of 600 mL and a whiteness of 82.0% is paired with an interfiber binding inhibitor (trademark: High Softer PX2, melting point 52 ° C., manufactured by Meisei Chemical Industries). 2 parts were added per 100 parts of the pulp dryness, and the pulp sheet made using a paper making machine was dried at 90 ° C. to produce a bulky pulp.
50 parts of bulky pulp that has been heat-dried by containing the interfiber binding inhibitor, and 400 parts of Canadian standard freeness (CSF) of 400 mL, LBKP with a whiteness of 81.5% (the amount of dry pulp is 100 Part) was made by the same chemical formulation and paper making method as in Example 1, basis weight 70.8 g / m ² , density 0.59 g / cm ³ , Oken smoothness 15 Got a second printing paper.

Example 4
Canada Standard Freeness (CSF) 700mL, Whiteness 80.7% Conifer Bleached Chemical Pulp (NBKP) slurry (Trademark: KB115, manufactured by Kao) was added 2 parts per 100 parts dry weight of pulp. A pulp sheet made using a lifting machine was dried at 90 ° C., and a bulky pulp subjected to a heat drying treatment containing an interfiber bond inhibitor was produced.
50 parts of bulky pulp that has been heat-dried by containing the interfiber binding inhibitor, and 400 parts of Canadian standard freeness (CSF) of 400 mL, LBKP with a whiteness of 81.5% (the amount of dry pulp is 100 Part) was produced by the same chemical formulation and paper making method as in Example 1, basis weight 73.2 g / m ² , density 0.61 g / cm ³ , Oken smoothness 15 Got a second printing paper.

Comparative Example 1
Using LBKP having a Canadian freeness (CSF) of 600 mL and a whiteness of 82.0% without using bulky pulp, the paper was made by the same chemical formulation and papermaking method as in Example 1, and the basis weight was 72. A printing paper having 6 g / m ² , density of 0.61 g / cm ³ and Oken type smoothness of 15 seconds was obtained.

Comparative Example 2
A pulp slurry containing 400 parts of CSF, 50 parts of broad-leaved BCTMP with a whiteness of 75.6%, 400 parts of Canadian standard freeness (CSF), 50 parts of LBKP with a whiteness of 81.5% (100 parts of dry pulp) Using the same chemical formulation and paper making method as in Example 1, printing paper having a basis weight of 67.2 g / m ² , a density of 0.56 g / cm ³ , and an Oken type smoothness of 15 seconds was obtained.

Comparative Example 3
A pulp slurry containing 400 parts of CSF, 20 parts of broad-leaved tree BCTMP having a whiteness of 75.6%, 400 parts of Canadian standard freeness (CSF), and 80 parts of LBKP having a whiteness of 81.5% (amount of dry pulp of 100 parts). Using the same chemical formulation and paper making method as in Example 1, printing paper having a basis weight of 71.9 g / m ² , density of 0.60 g / cm ³ , and Oken type smoothness of 15 seconds was obtained.

Comparative Example 4
Without using bulky pulp, Canada standard freeness (CSF) 400mL, whiteness 81.5% LBKP slurry 100 parts 1 part interfiber binder (trademark: KB115, manufactured by Kao) 100 parts), and the same chemical formula and paper making method as in Example 1 were used to make a paper. The printing paper had a basis weight of 71.4 g / m ² , density of 0.60 g / cm ³ , and Oken type smoothness of 15 seconds. Got.

Comparative Example 5
Using LBKP having a Canadian standard freeness (CSF) of 400 mL and a whiteness of 81.5% without using bulky pulp, papermaking is performed by the same chemical formulation and papermaking method as in Example 1, and the basis weight is 75 g / A printing paper having m ² , density of 0.63 g / cm ³ and Oken type smoothness of 15 seconds was obtained.

Claims (3)

A method for producing a bulky pulp, wherein an interfiber bond inhibitor is added and mixed in a bleached chemical pulp slurry, and then heated to a melting point or higher of the interfiber bond inhibitor and dried. After the Canadian standard freeness (CSF) of the bleached chemical pulp slurry is in the range of 300 mL to 600 mL and the interfiber binding inhibitor is added, the mixture is heated to the melting point of the interfiber binding inhibitor or higher and dried. A feature of producing bulky pulp. A paper blended with bulky pulp produced by the method of claims 1 and 2.