WO2019189611A1 - ミクロフィブリルセルロース繊維を含有する紙 - Google Patents
ミクロフィブリルセルロース繊維を含有する紙 Download PDFInfo
- Publication number
- WO2019189611A1 WO2019189611A1 PCT/JP2019/013682 JP2019013682W WO2019189611A1 WO 2019189611 A1 WO2019189611 A1 WO 2019189611A1 JP 2019013682 W JP2019013682 W JP 2019013682W WO 2019189611 A1 WO2019189611 A1 WO 2019189611A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- paper
- cellulose
- mfc
- chemically modified
- pulp
- Prior art date
Links
Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
- D21H11/18—Highly hydrated, swollen or fibrillatable fibres
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
- D21H11/20—Chemically or biochemically modified fibres
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/25—Cellulose
Definitions
- the present invention relates to a paper containing microfibril cellulose fibers.
- Patent Document 1 includes a paper substrate to which oxidized pulp is added
- Patent Document 2 includes a co-processed microfibril cellulose and an inorganic particle composition. Is disclosed.
- Patent Document 1 oxidized pulp is used, but the oxidized pulp is not sufficiently dispersible in the paper stock, and the reinforcing effect of the paper and the air resistance are not at a sufficient level.
- Patent Document 2 microfibril cellulose obtained by mechanically treating unmodified pulp together with inorganic particles is used. However, the microfibril cellulose is not sufficiently dispersible in the paper, and the reinforcing effect of the paper and the air resistance are not at a sufficient level. In view of such circumstances, an object of the present invention is to provide a paper having excellent strength and air resistance.
- the chemically modified cellulose can loosen the cellulose fibers more efficiently than the untreated cellulose by electrostatic repulsion of the introduced functional group. For this reason, when chemically modified cellulose is beaten, microfibril cellulose having advanced fibrillation and shortening of fibers compared to the case of beating cellulose not chemically modified can be obtained.
- the inventors of the present invention have good dispersibility when the microfibril cellulose is added to the stock, and the paper obtained from the stock has excellent mechanical strength and has a higher air resistance. I found out. That is, the said subject is solved by the following this invention. (1) Paper containing mechanically treated chemically modified microfibril cellulose fibers having an average fiber diameter of 500 nm or more.
- (8) a step of wet-grinding a cellulose raw material to prepare the microfibril cellulose fiber, and a step of preparing a stock containing the microfibril cellulose fiber,
- the present invention can provide paper having excellent strength and air resistance.
- X to Y includes X and Y which are their end values.
- the paper of the present invention has a base paper layer and may have one or more coating layers.
- the coating layer may be a pigment coating layer containing an inorganic pigment and an adhesive, or may be a clear coating layer mainly containing an adhesive without containing an inorganic pigment.
- the paper of this invention should just contain the microfibril cellulose fiber in any layer which comprises the said paper.
- microfibril cellulose fibers are contained in a base paper layer, a pigment coating layer, or a clear coating layer. These layers will be described later.
- Microfibril cellulose fiber is a fiber having an average fiber diameter of 500 nm or more obtained by fibrillating a cellulose-based raw material such as pulp. Unlike the cellulose nanofiber in which the fiber is refined until the fiber diameter becomes less than 500 nm, the microfibril cellulose of the present invention efficiently promotes fibrillation on the fiber surface while maintaining the shape of the pulp fiber to some extent.
- the average fiber diameter is 500 nm or more.
- the average fiber diameter is preferably larger than 1 ⁇ m, more preferably 2 ⁇ m or more, and further preferably 10 ⁇ m or more.
- the upper limit is preferably 60 ⁇ m or less.
- the average fiber diameter is a length-weighted average fiber diameter, and the fiber diameter can be measured with a fiber tester manufactured by ABB Corporation.
- MFC is obtained by subjecting a chemically modified cellulosic material to mechanical processing such as defibrating or beating relatively weakly with a beater, a disperser, a refiner, or the like. Therefore, MFC has a larger fiber diameter than cellulose nanofibers with an average fiber diameter of about 1 nanon to less than 500 nm obtained by strongly defibrating cellulose-based raw materials, and the fibers themselves are made finer (internal fibrillation). ) And the fiber surface is fluffed efficiently (external fibrillation).
- the mechanically treated chemically modified cellulose fiber (hereinafter also referred to as “mechanically treated chemically modified MFC”) used in the present invention is subjected to mechanical treatment after chemically modifying the pulp, or chemically modified pulp subjected to mechanical treatment.
- the former is preferable.
- the mechanically treated chemically modified MFC is obtained by subjecting a chemically modified cellulose-based raw material to mechanical treatment such as relatively weak defibration or beating, so that strong hydrogen bonds existing between fibers are caused by chemical modification.
- MFC which was weakened and simply mechanically defibrated or beaten without chemical modification
- the fibers were more easily loosened, less damaged by the fibers, and moderately internal and external fibrillated. It has a shape (see FIG. 2).
- an aqueous dispersion obtained by dispersing mechanically treated chemically modified MFC in water has high hydrophilicity, water retention, and viscosity.
- MFC has a different degree of fibrillation from cellulosic materials. Although it is generally not easy to quantify the degree of fibrillation, in the present invention, it is possible to quantify the degree of fibrillation based on the amount of freeness and water retention before and after mechanical treatment of MFC. I found out.
- the degree of fibrillation can be specified regardless of the degree of chemical modification by defining in this way because the freeness of pulp as a raw material is used as a reference.
- F 0 varies depending on the degree of pulp modification, it is difficult to unambiguously determine the upper limit of ⁇ F, but the freeness F after treatment is preferably greater than 0 ml.
- F In order for F to be 0 ml of MFC, strong mechanical defibration is required, and thus the MFC thus obtained may have an average fiber diameter of less than 500 nm (cellulose nanofiber).
- the average fine fiber rate of the mechanically treated chemically modified MFC of the present invention is preferably 4.0 or more, more preferably 4.5 or more, still more preferably 5.0 or more, and most preferably 8.0 or more.
- the average fine fiber rate is a value calculated as an item such as “(average) fibrillation rate (Mean fibril area)”, “average fine fiber rate”, or “fibril area” when fibers are measured with a fiber analyzer. This is one of the indicators of the degree of fibrillation of the main fibers. For example, it can be measured with a fiber tester or fiber tester plus manufactured by ABB, and in this application, the average fine fiber rate is preferably defined as “Mean fibril area” measured with a fiber tester plus.
- the lower limit of the Canadian standard freeness of the mechanically treated chemically modified MFC of the present invention is not limited, but is preferably higher than 0 ml.
- the upper limit of the freeness is preferably 500 ml or less, more preferably 350 ml or less, more preferably 150 ml or less, and particularly preferably 100 ml or less.
- the Canadian standard freeness of cellulose nanofibers that have been defibrated to the single nano level is 0 ml.
- the degree of fibrillation of the mechanically treated chemically modified MFC of the present invention can be quantified by increasing the water retention (H) of the pulp as described above.
- the ratio of H-type and Na-type changes depending on the pH, and the degree of water retention changes.
- the water retention of the mechanically treated chemically modified MFC of the present invention is preferably 210% or more, more preferably 250% or more, and further preferably 500% or more.
- the mechanically treated chemically modified MFC is sufficiently fibrillated, and the effects of the present invention can be obtained at a high level.
- the mechanically treated chemically modified MFC of the present invention when the degree of fibrillation is weak, the degree of fibrillation can be evaluated by the freeness, but when fibrillation is strongly carried out, short fibers are simultaneously formed with fibrillation of the fibers. As the process proceeds, the fibers may come off the mesh and the freeness may increase apparently. In such a case, since the degree of fibrillation cannot be correctly evaluated by the freeness, it is preferable to evaluate by the rate of change of the water retention. That is, the mechanically treated chemically modified MFC of the present invention is preferably chemically modified cellulose that has been mechanically treated so that ⁇ F is 10 ml or more or ⁇ H is 10% or more.
- the mechanically treated chemically modified MFC of the present invention has a high cellulose I type crystallinity, the strength of the MFC increases, and the strength of the paper containing it increases.
- the cellulose I-type crystallinity is preferably 40% or more, more preferably 50 or more.
- the upper limit of the cellulose I-type crystallinity is not limited, but is preferably 90 or less.
- Cellulose type I crystallinity can be measured by X-ray diffraction.
- mechanically treated chemically modified MFCs are lyophilized using liquid nitrogen and compressed to produce tablet shaped pellets.
- Cellulose-based material The cellulose-based material is not particularly limited, and examples thereof include those derived from plants, animals (for example, ascidians), algae, microorganisms (for example, acetic acid bacteria (Acetobacter)), and microorganism products.
- plant-derived materials include wood, bamboo, hemp, jute, kenaf, farmland waste, cloth, pulp (conifer unbleached kraft pulp (NUKP), conifer bleach kraft pulp (NBKP), hardwood unbleached kraft pulp ( LUKP), hardwood bleached kraft pulp (LBKP), softwood unbleached sulfite pulp (NUSP), softwood bleached sulfite pulp (NBSP), thermomechanical pulp (TMP), recycled pulp, waste paper, etc.).
- the cellulose raw material used in the present invention may be any one or a combination thereof, but is preferably a plant or microorganism-derived cellulose fiber, more preferably a plant-derived cellulose fiber.
- the average fiber diameter of the cellulose fibers is not particularly limited, but is about 30 to 60 ⁇ m in the case of softwood kraft pulp, which is a general pulp, and about 10 to 30 ⁇ m in the case of hardwood kraft pulp. In the case of other pulps, the average fiber diameter of those having undergone general refining is about 50 ⁇ m.
- a disintegrator such as a refiner or beater to adjust the average fiber diameter to about 50 ⁇ m or less, and to about 30 ⁇ m or less. It is more preferable.
- a method for producing mechanically treated chemically modified MFC will be described.
- Chemical modification means introducing a functional group into a cellulosic raw material.
- an anionic group include acid groups such as a carboxyl group, a carboxyl group-containing group, a phosphate group, and a phosphate group-containing group.
- the carboxyl group-containing group include —COOH group, —R—COOH (R is an alkylene group having 1 to 3 carbon atoms), and —O—R—COOH (R is an alkylene group having 1 to 3 carbon atoms). It is done.
- the phosphoric acid group-containing group examples include a polyphosphoric acid group, a phosphorous acid group, a phosphonic acid group, and a polyphosphonic acid group.
- these acid groups may be introduced in the form of a salt (for example, a carboxylate group (—COOM, M is a metal atom)).
- the chemical modification is preferably oxidation or etherification.
- Oxidized cellulose is obtained by oxidizing the cellulose raw material.
- the oxidation method is not particularly limited, for example, the cellulose raw material is oxidized in water using an oxidizing agent in the presence of an N-oxyl compound and a substance selected from the group consisting of bromide, iodide, and a mixture thereof. The method of doing is mentioned.
- the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized to produce a group selected from the group consisting of an aldehyde group, a carboxyl group, and a carboxylate group.
- concentration of the cellulose raw material at the time of reaction is not specifically limited, 5 weight% or less is preferable.
- the N-oxyl compound is a compound capable of generating a nitroxy radical.
- the nitroxyl radical include 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO).
- TEMPO 2,2,6,6-tetramethylpiperidine 1-oxyl
- the amount of the N-oxyl compound used is not particularly limited as long as it is a catalyst amount that can oxidize cellulose as a raw material.
- 0.01 mmol or more is preferable and 0.02 mmol or more is more preferable with respect to 1 g of absolutely dry cellulose.
- the upper limit is preferably 10 mmol or less, more preferably 1 mmol or less, and even more preferably 0.5 mmol or less. Therefore, the amount of the N-oxyl compound used is preferably 0.01 to 10 mmol, more preferably 0.01 to 1 mmol, and still more preferably 0.02 to 0.5 mmol with respect to 1 g of absolutely dry cellulose.
- Bromide is a compound containing bromine, and examples thereof include alkali metal bromide that can be dissociated and ionized in water, such as sodium bromide.
- the iodide is a compound containing iodine, and examples thereof include alkali metal iodide.
- the amount of bromide or iodide used can be selected as long as the oxidation reaction can be promoted.
- the total amount of bromide and iodide is preferably 0.1 mmol or more, more preferably 0.5 mmol or more, based on 1 g of absolutely dry cellulose.
- the upper limit of the amount is preferably 100 mmol or less, more preferably 10 mmol or less, and even more preferably 5 mmol or less.
- the total amount of bromide and iodide is preferably from 0.1 to 100 mmol, more preferably from 0.1 to 10 mmol, and even more preferably from 0.5 to 5 mmol, based on 1 g of absolutely dry cellulose.
- the oxidizing agent is not particularly limited, and examples thereof include halogen, hypohalous acid, halous acid, perhalogen acid, salts thereof, halogen oxide, and peroxide.
- hypohalous acid or a salt thereof is preferable because it is inexpensive and has a low environmental burden
- hypochlorous acid or a salt thereof is more preferable
- sodium hypochlorite is more preferable.
- the amount of the oxidizing agent used is preferably 0.5 mmol or more, more preferably 1 mmol or more, and further preferably 3 mmol or more with respect to 1 g of absolutely dry cellulose.
- the upper limit of the amount is preferably 500 mmol or less, more preferably 50 mmol or less, and even more preferably 25 mmol or less.
- the amount of the oxidizing agent used is preferably 0.5 to 500 mmol, more preferably 0.5 to 50 mmol, still more preferably 1 to 25 mmol, and particularly preferably 3 to 10 mmol with respect to 1 g of absolutely dry cellulose.
- the amount of the oxidizing agent used is preferably 1 mol or more with respect to 1 mol of the N-oxyl compound, and the upper limit is preferably 40 mol. Accordingly, the amount of the oxidizing agent used is preferably 1 to 40 mol with respect to 1 mol of the N-oxyl compound.
- the conditions such as pH and temperature during the oxidation reaction are not particularly limited, and generally the oxidation reaction proceeds efficiently even under relatively mild conditions.
- the reaction temperature is preferably 4 ° C or higher, more preferably 15 ° C or higher.
- the upper limit of the temperature is preferably 40 ° C. or lower, and more preferably 30 ° C. or lower. Accordingly, the reaction temperature is preferably 4 to 40 ° C., and may be about 15 to 30 ° C., that is, room temperature.
- the pH of the reaction solution is preferably 8 or more, and more preferably 10 or more.
- the upper limit of pH is preferably 12 or less, and more preferably 11 or less. Accordingly, the pH of the reaction solution is preferably about 8 to 12, more preferably about 10 to 11.
- the reaction medium for the oxidation is preferably water for reasons such as ease of handling and the difficulty of side reactions.
- the reaction time in the oxidation can be appropriately set according to the progress of the oxidation, and is usually 0.5 hours or more, and the upper limit is usually 6 hours or less, preferably 4 hours or less. Therefore, the reaction time in the oxidation is usually 0.5 to 6 hours, for example, about 0.5 to 4 hours.
- Oxidation may be carried out in two or more stages. For example, by oxidizing the oxidized cellulose obtained by filtration after the completion of the first-stage reaction again under the same or different reaction conditions, the efficiency is not affected by the reaction inhibition by the salt generated as a by-product in the first-stage reaction. Can be oxidized well.
- ozone oxidation Another example of the carboxylation (oxidation) method is ozone oxidation.
- the ozone treatment is usually performed by bringing a gas containing ozone and a cellulose raw material into contact with each other.
- the ozone concentration in the gas is preferably 50 g / m 3 or more.
- the upper limit is preferably 250 g / m 3 or less, and more preferably 220 g / m 3 or less.
- the ozone concentration in the gas is preferably 50 to 250 g / m 3 , and more preferably 50 to 220 g / m 3 .
- the amount of ozone added is preferably 0.1% by weight or more, and more preferably 5% by weight or more, based on 100% by weight of the solid content of the cellulose raw material.
- the upper limit of the amount of ozone added is usually 30% by weight or less. Therefore, the amount of ozone added is preferably 0.1 to 30% by weight and more preferably 5 to 30% by weight with respect to 100% by weight of the solid content of the cellulose raw material.
- the ozone treatment temperature is usually 0 ° C. or higher, preferably 20 ° C. or higher, and the upper limit is usually 50 ° C. or lower.
- the ozone treatment temperature is preferably 0 to 50 ° C., and more preferably 20 to 50 ° C.
- the ozone treatment time is usually 1 minute or longer, preferably 30 minutes or longer, and the upper limit is usually 360 minutes or shorter. Accordingly, the ozone treatment time is usually about 1 to 360 minutes, and preferably about 30 to 360 minutes.
- the ozone-treated cellulose may be further oxidized using an oxidizing agent.
- the oxidizing agent used for the additional oxidation treatment is not particularly limited, and examples thereof include chlorine compounds such as chlorine dioxide and sodium chlorite, oxygen, hydrogen peroxide, persulfuric acid, and peracetic acid.
- Examples of the method for the additional oxidation treatment include a method in which these oxidizing agents are dissolved in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and the cellulose raw material is immersed in the oxidizing agent solution.
- the amount of carboxyl group, carboxylate group, and aldehyde group contained in the oxidized MFC can be adjusted by controlling the oxidizing conditions such as the amount of the oxidizing agent added and the reaction time.
- the amount of carboxyl groups in the oxidized cellulose thus measured is preferably 0.1 mmol / g or more, more preferably 0.5 mmol / g or more, and further 0.8 mmol / g or more based on the absolute dry weight.
- the upper limit of the amount is preferably 3.0 mmol / g or less, more preferably 2.5 mmol / g or less, and further preferably 2.0 mmol / g or less. Therefore, the amount is preferably 0.1 to 3.0 mmol / g, more preferably 0.5 to 2.5 mmol / g, and still more preferably 0.8 to 2.0 mmol / g.
- the degree of carboxymethyl substitution per anhydroglucose unit in carboxymethylated cellulose or MFC obtained by carboxymethylation is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.10 or more.
- the upper limit of the degree of substitution is preferably 0.50 or less, more preferably 0.40 or less, and still more preferably 0.35 or less. Accordingly, the degree of carboxymethyl group substitution is preferably 0.01 to 0.50, more preferably 0.05 to 0.40, and even more preferably 0.10 to 0.30.
- the carboxymethylation method is not particularly limited, and examples thereof include a method in which a cellulose raw material as a bottoming raw material is mercerized and then etherified.
- a solvent is usually used.
- the solvent include water, alcohol (for example, lower alcohol), and a mixed solvent thereof.
- the lower alcohol include methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, and tertiary butanol.
- the mixing ratio of the lower alcohol in the mixed solvent the lower limit is usually 60% by weight or more, and the upper limit is 95% by weight or less, preferably 60 to 95% by weight.
- the amount of the solvent is usually 3 times the weight of the cellulose raw material. Although the upper limit of the amount is not particularly limited, it is 20 times by weight. Therefore, the amount of the solvent is preferably 3 to 20 times by weight.
- Mercerization is usually performed by mixing the bottoming material and mercerizing agent.
- mercerizing agents include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide.
- the amount of mercerizing agent used is preferably 0.5 moles or more, more preferably 1.0 moles or more, and even more preferably 1.5 moles or more per anhydroglucose residue of the starting material.
- the upper limit of the amount is usually 20 times mol or less, preferably 10 times mol or less, more preferably 5 times mol or less, and hence the amount of mercerizing agent used is preferably 0.5 to 20 times mol, and 1.0 More preferably, it is ⁇ 10 times mole, and more preferably 1.5 to 5 times mole.
- the reaction temperature for mercerization is usually 0 ° C. or higher, preferably 10 ° C. or higher, and the upper limit is usually 70 ° C. or lower, preferably 60 ° C. or lower. Accordingly, the reaction temperature is usually 0 to 70 ° C., preferably 10 to 60 ° C.
- the reaction time is usually 15 minutes or longer, preferably 30 minutes or longer.
- the upper limit of the time is usually 8 hours or less, preferably 7 hours or less. Accordingly, the reaction time is usually 15 minutes to 8 hours, preferably 30 minutes to 7 hours.
- the etherification reaction is usually performed by adding a carboxymethylating agent to the reaction system after mercerization.
- the carboxymethylating agent include sodium monochloroacetate.
- the addition amount of the carboxymethylating agent is usually preferably 0.05 times mol or more, more preferably 0.5 times mol or more, further preferably 0.8 times mol or more per glucose residue of the cellulose raw material.
- the upper limit of the amount is usually 10.0 times mole or less, preferably 5 moles or less, more preferably 3 times mole or less, and therefore the amount is preferably 0.05 to 10.0 times mole, more
- the amount is preferably 0.5 to 5, more preferably 0.8 to 3 moles.
- the reaction temperature is usually 30 ° C. or higher, preferably 40 ° C.
- the upper limit is usually 90 ° C. or lower, preferably 80 ° C. or lower.
- the reaction temperature is usually 30 to 90 ° C., preferably 40 to 80 ° C.
- the reaction time is usually 30 minutes or longer, preferably 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 4 hours or shorter. Therefore, the reaction time is usually 30 minutes to 10 hours, preferably 1 hour to 4 hours.
- the reaction solution may be stirred as necessary during the carboxymethylation reaction.
- Measurement of the degree of carboxymethyl substitution per glucose unit of carboxymethylated cellulose is, for example, by the following method. That is, 1) About 2.0 g of carboxymethylated cellulose (absolutely dry) is precisely weighed and put into a 300 mL conical stoppered Erlenmeyer flask. 2) Add 100 mL of a solution obtained by adding 100 mL of special grade concentrated nitric acid to 1000 mL of nitric acid methanol and shake for 3 hours to convert the carboxymethylcellulose salt (carboxymethylated cellulose) to hydrogen-type carboxymethylated cellulose.
- the chemically modified cellulose is mechanically defibrated or beaten so that the average fiber diameter is 500 nm or more.
- mechanical defibration or beating is referred to as “mechanical treatment”
- mechanical treatment for an aqueous dispersion of cellulose as a raw material is referred to as “wet grinding”.
- the defibrating or beating process may be performed once, or may be performed a plurality of times alone or in combination. In the case of multiple times, the timing of each defibration or beating may be anytime, and the apparatus used may be the same or different.
- the apparatus used for the defibration or beating process is not particularly limited, and examples thereof include high-speed rotation type, colloid mill type, high-pressure type, roll mill type, ultrasonic type, etc., and high-pressure or ultra-high pressure homogenizer, refiner,
- a material such as a beater, a PFI mill, a kneader, or a disperser that causes a metal or blade and pulp fibers to act around the rotation axis, or a material that is caused by friction between pulp fibers can be used.
- the concentration (solid content concentration) of the chemically modified pulp in the aqueous dispersion is usually 0.1% by weight.
- the above is preferable, 0.2% by weight or more is more preferable, and 0.3% by weight or more is more preferable.
- the liquid quantity with respect to the quantity of chemically modified cellulose becomes an appropriate quantity and becomes efficient.
- the upper limit of the concentration is not particularly limited as long as fibrillation or beating can be performed, but it is usually preferably 90% by weight or less, more preferably 50% by weight or less, and further preferably 40% by weight or less.
- the mechanically treated chemically modified MFC is obtained by this process.
- the average fiber diameter of the mechanically treated chemically modified MFC is 500 nm or more in terms of length-weighted average fiber diameter, preferably 1 ⁇ m or more, and more preferably 10 ⁇ m or more.
- the upper limit of the average fiber diameter is preferably 60 ⁇ m or less, and more preferably 40 ⁇ m or less.
- the average fiber length is preferably 300 ⁇ m or more, more preferably 500 ⁇ m or more, and further preferably 800 ⁇ m or more in terms of length-weighted average fiber length.
- the upper limit of the average fiber length is preferably 3000 ⁇ m or less, preferably 1500 ⁇ m or less, and more preferably 1100 ⁇ m or less.
- the mechanically treated chemically modified MFC of the present invention since raw pulp is chemically modified in advance, fibrillation and fiber shortening are likely to proceed when mechanical fibrillation or beating. Also, the mechanically treated chemically modified MFC of the present invention is different from CNF. In general, CNF is subjected to a strong defibrating process, and thus fine fiber progresses and is accompanied by a decrease in fiber width. However, the mechanically treated chemically modified MFC of the present invention does not perform a defibrating process as strong as CNF. Since treatment for promoting fibrillation such as weak defibration or beating is performed, fibrillation or shortening of the fiber occurs while maintaining the fiber width.
- the length-weighted average fiber diameter and the length-weighted average fiber length are determined using a fiber tester manufactured by ABB Corporation or a fractionator manufactured by Valmet Corporation.
- the average aspect ratio of the mechanically treated chemically modified MFC is preferably 10 or more, and more preferably 30 or more. Although an upper limit is not specifically limited, 1000 or less are preferable, 100 or less are more preferable and 80 or less are further more preferable.
- the amount of carboxyl groups in the mechanically treated oxidized MFC obtained in this step is preferably the same as the amount of carboxyl groups in the oxidized cellulose described above.
- the degree of substitution per glucose unit of the mechanically treated carboxymethylated MFC obtained in this step is preferably the same as the degree of substitution of carboxymethyl cellulose.
- the mechanically treated chemically modified MFC of the present invention may contain metal ions, and the total amount is preferably 0 or more and less than 10 mg / g.
- the metal ion include Ag, Au, Pt, Ni, Mn, Fe, Ti, Al, Zn, Cu, and the like, and preferably a metal ion having a valence of 2 or more.
- the content of the metal ion can be confirmed by a scanning electron microscope image and ICP emission analysis of the extract with a strong acid. That is, the presence of metal ions cannot be confirmed in the scanning electron microscope image, while it can be confirmed that the metal ions are contained in the ICP emission analysis.
- the mechanically treated chemically modified MFC of the present invention is used by mixing with other papermaking chemicals in the process of paper production (paper making, coating, etc.). Many chemicals with electric charges such as cations and anions are used for papermaking chemicals. If the balance of electric charges in the system is lost, problems such as agglomeration may occur, and mechanical properties with a high metal ion content may occur. When processing chemically modified MFC is used, the charge balance in the system may be lost. Therefore, the metal ion content is preferably less than 10 mg / g in order to reduce troubles in the papermaking process.
- the paper of the present invention may contain mechanically treated chemically modified MFC in the base paper layer, or may contain mechanically treated chemically modified MFC in the coating layer.
- the former is also called “internal addition” and the latter is also called “external addition”.
- the content of mechanically treated chemically modified MFC in the paper of the present invention is preferably less than 20% by weight, more preferably 10% by weight or less, in the total pulp (total of mechanically treated chemically modified MFC and other pulps). is there.
- the amount of mechanically treated chemically modified MFC is 20% by weight or more, in the case of internal addition, drainage of the pulp may be deteriorated and the operability may be deteriorated.
- the coating liquid is dried. There is a risk that efficiency will deteriorate.
- the paper of the present invention can be used for applications such as paper, paperboard, information paper, industrial paper, and cardboard.
- the base paper layer is a layer that becomes a base of paper and contains pulp as a main component.
- the base paper may be a single layer or a multilayer.
- the base paper layer preferably contains mechanically treated chemically modified MFC.
- MFC mechanically treated chemically modified MFC
- the content of the MFC is preferably 1 ⁇ 10 ⁇ 4 to 10 parts by weight, more preferably 3 ⁇ 10 ⁇ 4 to 1 part by weight with respect to 100 parts by weight of the pulp in each layer.
- the pulp raw material of the base paper used in the present invention is not particularly limited.
- Mechanical pulp such as ground pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), deinked pulp (DIP), conifer kraft pulp ( Chemical pulps such as NKP) and softwood kraft pulp (LKP) can be used.
- deinking (waste paper) pulp it is possible to use selected waste paper such as high quality paper, medium quality paper, lower grade paper, newspaper, flyers, magazines, etc. or unselected waste paper in which these are mixed.
- the fillers include heavy calcium carbonate, light calcium carbonate, clay, silica, light calcium carbonate-silica composite, kaolin, calcined kaolin, deramikaolin, magnesium carbonate, barium carbonate, barium sulfate, hydroxide Inorganic fillers such as amorphous silica produced by neutralization of aluminum, calcium hydroxide, magnesium hydroxide, zinc hydroxide, zinc oxide, titanium oxide, sodium silicate with mineral acid, urea-formalin resin, melamine series Organic fillers such as resin, polystyrene resin and phenol resin are listed.
- the content of the filler in the base paper is preferably 5 to 20% by weight based on the weight of the base paper. In the present invention, even if the ash content in the paper is high, a decrease in paper strength is suppressed. Therefore, the filler content in the base paper is more preferably 10% by weight or more.
- a bulking agent a dry paper strength improver, a wet paper strength improver, a freeness improver, a dye, a neutral sizing agent, and the like may be used as necessary.
- the base paper is manufactured by a known paper making method. For example, it can be carried out using a long net paper machine, a gap former type paper machine, a hybrid former type paper machine, an on-top former type paper machine, a round net paper machine, etc., but is not limited thereto.
- the mechanically treated chemically modified MFC of the present invention When added to the base paper, it may be added at any step in the step of preparing the pulp slurry, but in order to improve the mixing efficiency of the MFC, the pulp refiner step or mixing It is preferable to add in the process.
- the MFC When the MFC is added in the mixing step, a mixture obtained by previously mixing the MFC with other auxiliary agents such as a filler and a retention agent may be added to the pulp slurry.
- the density of the base paper is preferably 0.2 g / cm 3 or more, more preferably 0.4 g / cm 3 or more.
- the paper of the present invention has a large number of fibrils on the mechanically treated chemically modified MFC surface.
- the presence of the fibrillated mechanically treated chemically modified MFC between the pulp fibers constituting the paper increases the bonding points between the pulp fibers, resulting in a paper strength enhancing effect. Since it is thought that it is expressed, a higher paper strength enhancing effect can be expressed in a relatively high density paper with a close fiber-to-fiber distance.
- the basis weight of the base paper is not particularly limited, but is preferably 20 g / m 2 or more, more preferably 30 g / m 2 or more, and further preferably more than 40 g / m 2 .
- the pigment coating layer is a layer containing a white pigment as a main component.
- a white pigment such as calcium carbonate, kaolin, clay, calcined kaolin, amorphous silica, zinc oxide, aluminum oxide, satin white, aluminum silicate, magnesium silicate, magnesium carbonate, titanium oxide, plastic pigment, etc. Is mentioned.
- the pigment coating layer contains an adhesive.
- the adhesive include oxidized starch, positive starch, urea phosphated starch, etherified starch such as hydroxyethyl etherified starch, various starches such as dextrin, proteins such as casein, soy protein, synthetic protein, polyvinyl Alcohol, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl-based polymers such as ethylene-vinyl acetate copolymer Polymer latex etc. are mentioned. These can be used alone or in combination of two or more, and it is preferable to use a starch adhesive and a styrene-butadiene copolymer in combination.
- the pigment coating layer may contain various auxiliary agents such as a dispersant, a thickener, an antifoaming agent, a colorant, an antistatic agent, and an antiseptic used in the general paper manufacturing field.
- a mechanically treated chemically modified MFC may be contained in the pigment coating layer.
- the amount is preferably 1 ⁇ 10 ⁇ 3 to 1 part by weight with respect to 100 parts by weight of the pigment. In the case of the said range, the pigment coating liquid with moderate water retention can be obtained, without increasing the viscosity of a coating liquid significantly.
- the pigment coating layer can be provided by coating the coating liquid on one side or both sides of the base paper by a known method.
- the solid content concentration in the coating solution is preferably about 30 to 70% by weight from the viewpoint of coating suitability.
- the pigment coating layer may be one layer, two layers, or three or more layers. When there are a plurality of pigment coating layers, the MFC may be present in any pigment coating layer.
- the coating amount of the pigment coating layer may be appropriately adjusted depending on the application, but in the case of a coated paper for printing, the total amount per side is 5 g / m 2 or more, preferably 10 g / m 2 or more. .
- the upper limit is preferably 30 g / m 2 or less, and preferably 25 g / m 2 or less.
- the paper of the present invention may have a clear (transparent) coating layer on one or both sides of the base paper.
- the amount of clear coating is preferably from 0.1 to 1.0 g / m 2 , more preferably from 0.2 to 0.8 g / m 2 in terms of solid content per side.
- the clear coating means, for example, various starches such as starch and oxidized starch using a coater (coating machine) such as a size press, a gate roll coater, a pre-metering size press, a curtain coater, and a spray coater.
- a coating liquid (surface treatment liquid) mainly composed of a water-soluble polymer such as polyacrylamide or polyvinyl alcohol is applied (size press) on a base paper.
- the mechanically treated chemically modified MFC of the present invention may be contained in the clear coating layer.
- the paper of the present invention preferably has a moisture content of 10% by weight or less after being conditioned under conditions of 23 ° C. and 50 ⁇ 2% according to JIS P8111. Since mechanically treated chemically modified MFC has a relatively high water retention rate, dehydration and drying may be difficult in the papermaking process. However, it is preferable to adjust the amount of the MFC and the amount of the modifying group so that the moisture content of the paper is within the above range because the dehydrating property and drying property can be improved in the paper making process. Moreover, the paper whose water content is 10% by weight or less has sufficient strength.
- the moisture content is higher than 10% by weight, hydrogen bonds existing between cellulose fibers of the pulp are hindered by water, and the strength of the paper, particularly the stiffness, may be reduced.
- the lower limit value of the moisture content is not limited, but is preferably 4% by weight or more.
- the paper of the present invention contains mechanically treated chemically modified MFC having a relatively high fiber diameter and a high fibrillation rate, it has excellent air resistance in addition to excellent strength.
- the paper of the present invention may contain mechanically treated chemically modified MFC in any one of the base paper, clear coating layer, and pigment coating layer constituting the paper.
- it is preferably manufactured through a process of preparing a stock containing mechanically treated chemically modified MFC.
- mechanically treated chemically modified It is preferably manufactured through a step of preparing a coating liquid containing MFC.
- the mechanically treated chemically modified MFC can be prepared by mechanically defibrating or beating a chemically modified cellulose raw material.
- the paper stock can be prepared according to a known method.
- the coating liquid can be prepared according to a known method.
- the MFC and additives as necessary may be added to a binder such as starch, and a white pigment may be added to the pigment coating. It may be a liquid.
- the paper can be produced by making a paper by a known method using the paper material thus obtained, or by coating the base paper with the coating liquid thus obtained. As described above, a clear coating or pigment coating layer can be provided on the surface of the paper.
- Evaluation Basis weight JIS P 8223: 2006 was used as a reference. Paper thickness and density: JIS P 8118: 2014 was followed. Ash content: According to JIS P 8251: 2003. Canadian Standard Freeness (csf: ml): JIS P 811-2: 2012 was followed. Air permeability resistance: Measured by Oken type smoothness / air permeability tester according to JIS P8117: 2009. Breaking length: According to JIS P 8113: 1998. Tensile stiffness: Measured by the method prescribed in ISO / DIS 1924-3. ISO bending stiffness: according to ISO 2493. MFC characteristics: The characteristics of MFC were measured with Fiber Tester Plus manufactured by ABB in Examples 1 and 2. The measurement conditions are as follows.
- Fiber tester plus measurement condition MFC dispersed in water so as to be 0.05% was measured according to a conventional method.
- the measurement items were average fiber length (Mean length), average fiber diameter (Mean width), average fine fiber ratio (Mean fibril area), and average fine rate (Mean ⁇ fines).
- Example 1-1 96 wt% LBKP (Nippon Paper Industries Co., Ltd., csf 400 ml), 4 wt% mechanically treated chemically modified MFC-A (csf 67 ml, COOH group amount 0.30 mmol / g) )
- a mixed pulp To the total amount of the mixed pulp, 1.5% by weight sulfuric acid band, 0.025% by weight polyethyleneimine, 0.6% by weight polyacrylamide and 0.2% by weight sizing agent were added to obtain a solid content.
- a pulp slurry having a concentration of 0.35% by weight was prepared.
- a handmade sheet having a basis weight of 50 g / m 2 was produced and evaluated using the obtained pulp slurry. Hand-drawing was performed according to JIS P 8222.
- Example 1-2 Similar to Example 1-1, except that mechanically treated chemically modified MFC-B (csf, 54 ml, COOH group content 0.58 mmol / g) was used instead of mechanically treated chemically modified MFC-A. Then, a handsheet was manufactured and evaluated.
- mechanically treated chemically modified MFC-B csf, 54 ml, COOH group content 0.58 mmol / g
- Examples 2-1 to 2-3 instead of LBKP, magazine waste paper-based undeinked pulp (manufactured by Nippon Paper Industries Co., Ltd., csf 350 ml) was used, and the addition amount of mechanically treated chemically modified MFC-A was 0.01 wt%, 1.0 A handsheet was produced and evaluated in the same manner as in Example 1-1 except that the weight percent was changed to 10% by weight.
- Examples 3-1 and 3-2, Comparative Example 7 96% by weight of LBKP (manufactured by Nippon Paper Industries Co., Ltd., csf 400 ml), 4% by weight of mechanically treated chemically modified MFC-D (COOH group amount 1.37 mmol / g) with different number of refiner passes Each was mixed into a mixed pulp. To the total amount of the mixed pulp, 1.5% by weight sulfuric acid band, 0.025% by weight polyethyleneimine, 0.6% by weight polyacrylamide and 0.2% by weight sizing agent were added to obtain a solid content. A pulp slurry having a concentration of 0.35% by weight was prepared.
- a handmade sheet having a target basis weight of 50 g / m 2 was produced and evaluated using the obtained pulp slurry. Hand-drawing was performed according to JIS P 8222.
- the MFC used in Comparative Example 7 is not a mechanically treated chemically modified MFC.
- the paper containing mechanically treated chemically modified MFC had higher tear length and air resistance, and the higher the fibrillation rate of MFC, the higher the tear length and air resistance. .
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Biochemistry (AREA)
- Paper (AREA)
Abstract
Description
(1)平均繊維径が500nm以上の機械的処理化学変性ミクロフィブリルセルロース繊維を含む紙。
(2)前記ミクロフィブリルセルロース繊維の繊維分析装置で測定した平均微細繊維率が4.0以上である、(1)に記載の紙。
(3)前記ミクロフィブリルセルロース繊維のセルロースI型結晶化度が50%以上である(1)または(2)に記載の紙。
(4)前記化学変性がアニオン変性である(1)~(3)のいずれかに記載の紙。
(5)顔料塗工層を備える(1)~(4)のいずれかに記載の紙。
(6)クリア塗工層を備える(1)~(5)のいずれかに記載の紙。
(7)JIS P 8111に従って23℃50±2%条件下で調湿した紙の含水率が10重量%以下である、(1)~(6)のいずれかに記載の紙。
(8)セルロース原料を湿式粉砕して前記ミクロフィブリルセルロース繊維を調製する工程、および
前記ミクロフィブリルセルロース繊維を含む紙料を調製する工程、
を備える、(1)~(7)のいずれかに記載の紙の製造方法。
(9)前記湿式粉砕の前にセルロース原料を化学変性する工程を備える、(8)に記載の製造方法。
本発明の紙は原紙層を有し、1層以上の塗工層を有してもよい。塗工層は無機顔料および接着剤を含有する顔料塗工層でもよく、無機顔料を含有せずに接着剤を主体とするクリア塗工層でもよい。本発明の紙は、当該紙を構成するいずれかの層にミクロフィブリルセルロース繊維を含んでいればよい。例えば、ミクロフィブリルセルロース繊維は原紙層または顔料塗工層またはクリア塗工層に含有される。これらの層に関しては後述する。
ミクロフィブリルセルロース繊維(以下「MFC」ともいう)とは、パルプ等のセルロース系原料をフィブリル化して得られる500nm以上の平均繊維径を有する繊維である。本発明のミクロフィブリルセルロースは繊維径が500nm未満となるまで繊維が微細化されたセルロースナノファイバーとは異なり、パルプ繊維の形状をある程度維持したまま効率的に繊維表面のフィブリル化が促進されるため、平均繊維径は500nm以上である。平均繊維径は1μmより大きいことが好ましく、2μm以上がより好ましく、10μm以上であることがさらに好ましい。その上限は60μm以下が好ましい。本発明において平均繊維径とは長さ加重平均繊維径であり、当該繊維径はABB株式会社製ファイバーテスターで測定できる。MFCは、化学変性したセルロース系原料をビーターやディスパーザー、リファイナーなどで比較的弱く解繊または叩解などの機械的処理をすることで得られる。したがってMFCは、セルロース系原料を強く解繊処理して得られるシングルナノ~500nm未満程度の平均繊維径を有するセルロースナノファイバーと比較して繊維径が大きく、また繊維自体の微細化(内部フィブリル化)を抑制しながら効率的に繊維表面を毛羽立たせた(外部フィブリル化した)形状を有する。
結晶I型 :2θ=14.8°、16.8°、22.6°
結晶II型:2θ=12.1°、19.8°、22.0°
セルロース系原料は、特に限定されないが、例えば、植物、動物(例えばホヤ類)、藻類、微生物(例えば酢酸菌(アセトバクター))、微生物産生物に由来するものが挙げられる。植物由来のものとしては、例えば、木材、竹、麻、ジュート、ケナフ、農地残廃物、布、パルプ(針葉樹未漂白クラフトパルプ(NUKP)、針葉樹漂白クラフトパルプ(NBKP)、広葉樹未漂白クラフトパルプ(LUKP)、広葉樹漂白クラフトパルプ(LBKP)、針葉樹未漂白サルファイトパルプ(NUSP)、針葉樹漂白サルファイトパルプ(NBSP)、サーモメカニカルパルプ(TMP)、再生パルプ、古紙等)が挙げられる。本発明で用いるセルロース原料は、これらのいずれかまたは組合せであってもよいが、好ましくは植物または微生物由来のセルロース繊維であり、より好ましくは植物由来のセルロース繊維である。
化学変性とはセルロース系原料に官能基を導入することをいい、本発明においてはアニオン性基を導入することが好ましい。アニオン性基としてはカルボキシル基、カルボキシル基含有基、リン酸基、リン酸基含有基等の酸基が挙げられる。カルボキシル基含有基としては、-COOH基、-R-COOH(Rは炭素数が1~3のアルキレン基)、-O-R-COOH(Rは炭素数が1~3のアルキレン基)が挙げられる。リン酸基含有基としては、ポリリン酸基、亜リン酸基、ホスホン酸基、ポリホスホン酸基等が挙げられる。これらの酸基は反応条件によっては、塩の形態(例えばカルボキシレート基(-COOM、Mは金属原子))で導入されることもある。本発明において化学変性は、酸化またはエーテル化が好ましい。以下、これらについて詳細に説明する。
セルロース原料を酸化することによって酸化セルロースが得られる。酸化方法は特に限定されないが、一例として、N-オキシル化合物と、臭化物、ヨウ化物およびこれらの混合物からなる群より選択される物質との存在下で、酸化剤を用いて水中でセルロース原料を酸化する方法が挙げられる。この方法によれば、セルロース表面のグルコピラノース環のC6位の一級水酸基が選択的に酸化され、アルデヒド基、カルボキシル基、およびカルボキシレート基からなる群より選ばれる基が生じる。反応時のセルロース原料の濃度は特に限定されないが、5重量%以下が好ましい。
カルボキシル基量〔mmol/g酸化セルロース〕=a〔mL〕×0.05/酸化セルロース重量〔g〕
エーテル化としては、カルボキシメチル(エーテル)化、メチル(エーテル)化、エチル(エーテル)化、シアノエチル(エーテル)化、ヒドロキシエチル(エーテル)化、ヒドロキシプロピル(エーテル)化、エチルヒドロキシエチル(エーテル)化、ヒドロキシプロピルメチル(エーテル)化などが挙げられる。この中から一例としてカルボキシメチル化の方法を以下に説明する。
A=[(100×F’-(0.1NのH2SO4)(mL)×F)×0.1]/(水素型カルボキシメチル化セルロースの絶乾質量(g))
DS=0.162×A/(1-0.058×A)
A:水素型カルボキシメチル化セルロースの1gの中和に要する1NのNaOH量(mL)
F:0.1NのH2SO4のファクター
F’:0.1NのNaOHのファクター
本工程では、化学変性セルロースを機械的に解繊または叩解し、平均繊維径を500nm以上とする。本発明において、機械的な解繊または叩解を「機械的処理」といい、原料であるセルロースの水分散体に対する機械的処理を「湿式粉砕」という。解繊または叩解処理は1回行ってもよいし、これらを単独でまたは組合せて複数回行ってもよい。複数回の場合それぞれの解繊または叩解の時期はいつでもよく、使用する装置は同一でも異なってもよい。
平均アスペクト比=平均繊維長/平均繊維径
本発明の紙は、後述するとおり、原紙層に機械的処理化学変性MFCを含有してもよいし、塗工層に機械的処理化学変性MFCを含有してもよい。前者を「内添」、後者を「外添」ともいう。本発明の紙における機械的処理化学変性MFCの含有量は、全パルプ(機械的処理化学変性MFCとこれ以外のパルプの合計)中、好ましくは20重量%未満、より好ましくは10重量%以下である。機械的処理化学変性MFCの量が20重量%以上であると、内添の場合はパルプの水切れが悪化し操業性が悪化する恐れがあり、外添の場合も同様に、塗工液の乾燥効率が悪化する恐れがある。本発明の紙は洋紙、板紙、情報用紙、産業用紙、および段ボールなどの用途に使用することができる。
原紙層とは紙のベースとなる層でありパルプを主成分として含む。本発明においては、原紙は単層でも多層でもよい。原紙層は機械的処理化学変性MFCを含むことが好ましい。多層の場合は原紙層のうち少なくともいずれか一層が前記MFCを含んでいればよく、全層が前記MFCを含有してもよい。前記MFCの含有量は各層のパルプ100重量部に対して1×10-4~10重量部であることが好ましく、3×10-4~1重量部であることがより好ましい。
顔料塗工層とは白色顔料を主成分として含む層である。白色顔料としては、炭酸カルシウム、カオリン、クレー、焼成カオリン、無定形シリカ、酸化亜鉛、酸化アルミニウム、サチンホワイト、珪酸アルミニウム、珪酸マグネシウム、炭酸マグネシウム、酸化チタン、プラスチックピグメント等の通常使用されている顔料が挙げられる。
本発明の紙は、原紙の片面または両面にクリア(透明)塗工層を有していてもよい。原紙上にクリア塗工を施すことにより、原紙の表面強度や平滑性を向上させることができ、また、顔料塗工をする際の塗工性を向上させることができる。クリア塗工の量は、片面あたり固形分で0.1~1.0g/m2が好ましく、0.2~0.8g/m2がより好ましい。本発明においてクリア塗工とは、例えば、サイズプレス、ゲートロールコータ、プレメタリングサイズプレス、カーテンコータ、スプレーコータなどのコータ(塗工機)を使用して、澱粉、酸化澱粉などの各種澱粉、ポリアクリルアミド、ポリビニルアルコールなどの水溶性高分子を主成分とする塗布液(表面処理液)を原紙上に塗布(サイズプレス)することをいう。本発明の機械的処理化学変性MFCをクリア塗工層中に含有してもよい。
本発明の紙は、JIS P8111に従って23℃50±2%条件下で調湿した後の紙の含水率が10重量%以下であることが好ましい。機械的処理化学変性MFCは保水率が比較的高いので製紙工程において脱水や乾燥が困難になることがある。しかし前記MFCの量および変性基の量を調整して紙の含水率を前記範囲とすることで、製紙工程において脱水性や乾燥性を良好にすることができるので好ましい。また、当該含水率が10重量%以下である紙は十分な強度を有する。当該含水率が10重量%より高いと、パルプのセルロース繊維間に存在する水素結合が水によって妨げられ、紙の強度、特にこわさが低下する恐れがある。この観点から、当該含水率の下限値は限定されないが4重量%以上であることが好ましい。
本発明の紙は、紙を構成する原紙、クリア塗工層、顔料塗工層のうちいずれか一層に機械的処理化学変性MFCを含有すればよい。高い強度向上効果を得るためには機械的処理化学変性MFCを含む紙料を調製する工程を経て製造されることが好ましく、高い透気抵抗度向上効果を得るためには、機械的処理化学変性MFCを含む塗工液を調製する工程を経て製造されることが好ましい。機械的処理化学変性MFCは前述のとおり、化学変性したセルロース原料を機械的に解繊または叩解して調製できる。紙料は公知の方法に準じて調製できる。例えばパルプを離解して得たスラリーに、前記MFC、填料、必要に応じて添加剤を添加して調製できる。また、塗工液は公知の方法に準じて調製でき、例えば澱粉などのバインダーに、前記MFCおよび必要に応じて添加剤を添加してしてもよく、さらに白色顔料を添加して顔料塗工液としてもよい。
(1)評価
坪量:JIS P 8223:2006を参考とした。
紙厚および密度:JIS P 8118:2014に従った。
灰分:JIS P 8251:2003に従った。
カナダ標準濾水度(csf:ml):JIS P 8121-2:2012に従った。
透気抵抗度:JIS P8117:2009に従い、王研式平滑度・透気度試験機により測定した。
裂断長:JIS P 8113:1998に従った。
引張こわさ:ISO/DIS 1924-3に規定された方法で測定した。
ISO曲げこわさ:ISO 2493に従った。
MFC特性:MFCの特性は、実施例1、2はABB社製ファイバーテスタープラスで測定した。測定条件は以下のとおりである。
[製造例1]NBKPからの機械的処理化学変性MFC調製1
定法に従いNBKP(日本製紙株式会社製)をTEMPO酸化処理し、表1に示すTEMPO酸化パルプA~Cを製造した。得られたTEMPO酸化パルプを水に分散し3重量%の分散液とし、リファイナーで処理した。目標c.s.f.、平均微細繊維率に合わせて、リファイナーのクリアランス、処理回数などの処理条件を変更し、機械的処理化学変性MFCを得た。これらの物性を表1に示す。また、得られたMFCの特性を表2および3に示す。
定法に従いNBKP(日本製紙株式会社製)をTEMPO酸化処理し、COOH基量がそれぞれ1.37であるTEMPO酸化パルプD(pH7.2のCSF 554ml)を得た。得られたTEMPO酸化パルプを水に分散し、4重量%の分散液とし、リファイナーで処理した。リファイナーの処理回数を変更し、機械的処理化学変性MFC-Dを得た。これらのMFC特性を表4に示す。機械的処理化学変性MFC-Dは微細繊維化が進みすぎたため、適正なc.s.f.の測定はできなかった。
96重量%のLBKP(日本製紙株式会社製、c.s.f.400ml)、4重量%の機械的処理化学変性MFC-A(c.s.f.67ml、COOH基量0.30mmol/g)を混合して混合パルプとした。当該混合パルプの合計量に対し、1.5重量%の硫酸バンド、0.025重量%のポリエチレンイミン、0.6重量%のポリアクリルアミド、0.2重量%のサイズ剤を添加して固形分濃度0.35重量%のパルプスラリーを調製した。得られたパルプスラリーを用いて坪量50g/m2の手抄きシートを製造して評価した。手抄きは、JIS P 8222に従って実施した。
機械的処理化学変性MFC-Aの代わりに機械的処理化学変性MFC-B(c.s.f.54ml、COOH基量0.58mmol/g)を用いた以外は、実施例1-1と同様にして手抄きシートを製造して評価した。
機械的処理化学変性MFCの代わりに、機械的処理をしていないTEMPO酸化パルプA(COOH基量0.30mmol/g、c.s.f.573ml)およびTEMPO酸化パルプB(COOH基量0.58mmol/g、c.s.f.364ml)を用いた以外は、実施例1-1と同様に手抄きシートを製造して評価した。
TEMPO酸化パルプAの代わりに未変性MFC(NBKP、COOH基量0mmol/g、c.s.f.450ml)を用いた以外は、比較例1と同様に手抄きシートを製造して評価した。
100重量%のLBKP(c.s.f.400ml)に対し、1.5重量%の硫酸バンド、0.025重量%のポリエチレンイミン、0.6重量%ポリアクリルアミド、0.2重量%サイズ剤を添加して固形分濃度0.35重量%のパルプスラリーを調製した。得られたパルプスラリーを用いて坪量50g/m2の手抄きシートを製造して評価した。これらの結果を表2に示す。
LBKPの代わりに雑誌古紙系未脱墨パルプ(日本製紙株式会社製、c.s.f.350ml)を用い、機械的処理化学変性MFC-Aの添加量を0.01重量%、1.0重量%、10重量%とそれぞれ変更した以外は、実施例1-1と同様にして手抄きシートを製造して評価した。
坪量を43.6g/m2に変更した以外は比較例4と同様にして手抄きシートを製造して評価した。これらの結果を表3に示す。
96重量%のLBKP(日本製紙株式会社製、c.s.f.400ml)、4重量%の、リファイナーパス回数の異なる機械的処理化学変性MFC-D(COOH基量1.37mmol/g)をそれぞれ混合して混合パルプとした。当該混合パルプの合計量に対し、1.5重量%の硫酸バンド、0.025重量%のポリエチレンイミン、0.6重量%のポリアクリルアミド、0.2重量%のサイズ剤を添加して固形分濃度0.35重量%のパルプスラリーを調製した。得られたパルプスラリーを用いて目標坪量50g/m2の手抄きシートを製造して評価した。手抄きは、JIS P 8222に従って実施した。比較例7で用いたMFCは機械的処理化学変性MFCではない。これらの結果を表4に示す。
機械的処理化学変性MFCを用いなかった以外は、実施例3-1と同様にして手抄きシートを製造して評価した。
Claims (9)
- 平均繊維径が500nm以上の機械的処理化学変性ミクロフィブリルセルロース繊維を含む紙。
- 前記ミクロフィブリルセルロース繊維の繊維分析装置で測定した平均微細繊維率が4.0以上である、請求項1に記載の紙。
- 前記ミクロフィブリルセルロース繊維のセルロースI型結晶化度が50%以上である1または2に記載の紙。
- 前記化学変性がアニオン変性である請求項1~3のいずれかに記載の紙。
- 顔料塗工層を備える請求項1~4のいずれかに記載の紙。
- クリア塗工層を備える請求項1~5のいずれかに記載の紙。
- JIS P 8111に従って23℃50±2%条件下で調湿した紙の含水率が10重量%以下である、請求項1~6のいずれかに記載の紙。
- セルロース原料を湿式粉砕して前記ミクロフィブリルセルロース繊維を調製する工程、および
前記ミクロフィブリルセルロース繊維を含む紙料を調製する工程、
を備える、請求項1~7のいずれかに記載の紙の製造方法。 - 前記湿式粉砕の前にセルロース原料を化学変性する工程を備える、請求項8に記載の製造方法。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2019244030A AU2019244030B2 (en) | 2018-03-30 | 2019-03-28 | Paper comprising microfibrillated cellulose fibers |
JP2020511002A JP7239561B2 (ja) | 2018-03-30 | 2019-03-28 | ミクロフィブリルセルロース繊維を含有する紙 |
CN201980023650.9A CN112105776A (zh) | 2018-03-30 | 2019-03-28 | 一种含有微原纤化纤维素纤维的纸 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2018-070236 | 2018-03-30 | ||
JP2018070236 | 2018-03-30 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2019189611A1 true WO2019189611A1 (ja) | 2019-10-03 |
Family
ID=68058232
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2019/013682 WO2019189611A1 (ja) | 2018-03-30 | 2019-03-28 | ミクロフィブリルセルロース繊維を含有する紙 |
Country Status (4)
Country | Link |
---|---|
JP (1) | JP7239561B2 (ja) |
CN (1) | CN112105776A (ja) |
AU (1) | AU2019244030B2 (ja) |
WO (1) | WO2019189611A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020195671A1 (ja) * | 2019-03-28 | 2020-10-01 | 日本製紙株式会社 | フィブリル化された化学変性セルロース繊維 |
JP2021080615A (ja) * | 2019-11-22 | 2021-05-27 | 三菱製紙株式会社 | 炭素短繊維不織布 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06136681A (ja) * | 1992-10-29 | 1994-05-17 | New Oji Paper Co Ltd | 新聞用紙 |
JPH10251301A (ja) * | 1997-03-07 | 1998-09-22 | Nippon Paper Ind Co Ltd | セルロース誘導体とその製法 |
JPH11140793A (ja) * | 1997-11-12 | 1999-05-25 | Nippon Paper Industries Co Ltd | 塗被紙用塗液添加物 |
JP2016223042A (ja) * | 2015-06-03 | 2016-12-28 | 王子ホールディングス株式会社 | パルプスラリー及びパルプシート |
WO2017014255A1 (ja) * | 2015-07-22 | 2017-01-26 | 日本製紙株式会社 | 金属含有セルロース繊維、それを用いた衛生薄葉紙及び吸収性物品 |
WO2017179717A1 (ja) * | 2016-04-14 | 2017-10-19 | 凸版印刷株式会社 | 積層体の製造方法、積層体、紙製包装材料 |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5462572B2 (ja) | 2008-09-30 | 2014-04-02 | 日本製紙株式会社 | 印刷用塗工紙およびその製造方法 |
FI124748B (fi) * | 2011-11-15 | 2015-01-15 | Upm Kymmene Corp | Paperituote sekä menetelmä ja järjestelmä seossuhteen valmistamiseksi |
WO2014097929A1 (ja) | 2012-12-19 | 2014-06-26 | 日本製紙株式会社 | 紙基材 |
JP6434782B2 (ja) | 2014-11-13 | 2018-12-05 | 日本製紙株式会社 | カチオン変性セルロース由来のセルロースナノファイバーを添加して抄紙した紙およびその製造方法 |
US10533060B2 (en) * | 2015-05-15 | 2020-01-14 | Nippon Paper Industries Co., Ltd. | Anion-modified cellulose nanofiber dispersion liquid and composition |
-
2019
- 2019-03-28 CN CN201980023650.9A patent/CN112105776A/zh active Pending
- 2019-03-28 AU AU2019244030A patent/AU2019244030B2/en active Active
- 2019-03-28 JP JP2020511002A patent/JP7239561B2/ja active Active
- 2019-03-28 WO PCT/JP2019/013682 patent/WO2019189611A1/ja active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06136681A (ja) * | 1992-10-29 | 1994-05-17 | New Oji Paper Co Ltd | 新聞用紙 |
JPH10251301A (ja) * | 1997-03-07 | 1998-09-22 | Nippon Paper Ind Co Ltd | セルロース誘導体とその製法 |
JPH11140793A (ja) * | 1997-11-12 | 1999-05-25 | Nippon Paper Industries Co Ltd | 塗被紙用塗液添加物 |
JP2016223042A (ja) * | 2015-06-03 | 2016-12-28 | 王子ホールディングス株式会社 | パルプスラリー及びパルプシート |
WO2017014255A1 (ja) * | 2015-07-22 | 2017-01-26 | 日本製紙株式会社 | 金属含有セルロース繊維、それを用いた衛生薄葉紙及び吸収性物品 |
WO2017179717A1 (ja) * | 2016-04-14 | 2017-10-19 | 凸版印刷株式会社 | 積層体の製造方法、積層体、紙製包装材料 |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020195671A1 (ja) * | 2019-03-28 | 2020-10-01 | 日本製紙株式会社 | フィブリル化された化学変性セルロース繊維 |
JPWO2020195671A1 (ja) * | 2019-03-28 | 2020-10-01 | ||
JP2021080615A (ja) * | 2019-11-22 | 2021-05-27 | 三菱製紙株式会社 | 炭素短繊維不織布 |
JP7077292B2 (ja) | 2019-11-22 | 2022-05-30 | 三菱製紙株式会社 | 炭素短繊維不織布 |
Also Published As
Publication number | Publication date |
---|---|
JP7239561B2 (ja) | 2023-03-14 |
AU2019244030A1 (en) | 2020-11-05 |
AU2019244030B2 (en) | 2023-04-06 |
CN112105776A (zh) | 2020-12-18 |
JPWO2019189611A1 (ja) | 2021-04-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5416531B2 (ja) | 填料の前処理方法および前処理された填料を含有する紙 | |
US11525015B2 (en) | Oxidized microfibrillated cellulose fibers and composition thereof | |
US11512432B2 (en) | Oxidized microfibrillated cellulose fibers and composition thereof | |
JP7425743B2 (ja) | セルロースナノファイバー含有塗工層を備える紙 | |
JP2024028775A (ja) | 微細セルロース繊維の製造方法およびそれを含有する紙 | |
WO2019189611A1 (ja) | ミクロフィブリルセルロース繊維を含有する紙 | |
JP7290976B2 (ja) | 紙または板紙の製造方法 | |
JP6948941B2 (ja) | セルロースナノファイバーを含有する紙または板紙 | |
JP2019173255A (ja) | セルロースナノファイバーを含有する紙または板紙 | |
JP2019173254A (ja) | セルロースナノファイバーを含有する紙または板紙 | |
WO2019189770A1 (ja) | セルロースナノファイバーを含有する紙 | |
JP7412899B2 (ja) | ミクロフィブリルセルロース繊維およびこれを含有する紙 | |
JP2020165036A (ja) | セルロースナノファイバーを含有する紙または板紙 | |
WO2019131994A1 (ja) | セルロースナノファイバーを含有する紙または板紙 | |
JP7312094B2 (ja) | カルボキシメチル化セルロースを含有する紙 | |
WO2019189615A1 (ja) | 紙または板紙の製造方法 | |
JP2020165037A (ja) | ミクロフィブリレイテッドセルロースを含有する紙または板紙 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 19774900 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2020511002 Country of ref document: JP Kind code of ref document: A |
|
ENP | Entry into the national phase |
Ref document number: 2019244030 Country of ref document: AU Date of ref document: 20190328 Kind code of ref document: A |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 19774900 Country of ref document: EP Kind code of ref document: A1 |