JP2021075674A - Adhesive composition, method for producing the same and application of the same - Google Patents

Abstract

To provide an adhesive composition capable of decreasing reduction in viscosity with time as can as possible.SOLUTION: There are provided: an adhesive composition comprising a component (A): a carboxymethyl cellulose or a salt thereof and a component (B): an anion-modified cellulose nanofiber, a method for producing the same; and a tail seal paste and a roll paper. The adhesive composition preferably further comprises a component (C): an acrylic polymer. The component (B) preferably includes an oxidized cellulose nanofiber in which the carboxyl group amount of the oxidized cellulose nanofiber is 0.60 to 2.0 mmol/g or a carboxymethylated cellulose nanofiber in which the carboxymethyl substitution degree of the carboxymethylated cellulose nanofiber is 0.010 to 0.50.SELECTED DRAWING: None

Description

The present invention relates to an adhesive composition, a method for producing the same, and an application thereof, and more particularly to an adhesive composition, a method for producing an adhesive composition, a tail seal glue using the adhesive composition, and a roll paper.

In roll products (roll paper) such as toilet paper, the end part of the roll and the start part of the roll are fixed with an adhesive called tail seal glue. As a material for such an adhesive, an adhesive composition containing an acrylic water-soluble polymer and an inorganic acid salt has been proposed (see Patent Document 1).

JP-A-2002-3807

Tail seal glue has the property of fixing the end of roll winding and the beginning of roll winding so that it does not come off during adhesion, the property of easily peeling off the paper so that it does not tear during use, and the property of paper being easily removed from the paper tube when discarded after use. Peeling characteristics are required. That is, it is desirable that the adhesive force is strong at the time of adhesion and weak at the time of use.
The adhesive composition described in Patent Document 1 has an adhesive strength that does not change with time. Therefore, if the adhesive force is designed to be strong so that the winding end portion of the roll does not come off during adhesion, the paper will be torn during use. On the other hand, if the adhesive strength is designed to be weak so that the paper does not tear during use, the end of the roll will come off during adhesion.

By the way, if a composition having a strong adhesive force at the time of adhesion and a weak adhesive force at the time of use is prepared, the viscosity of the composition decreases with time. The decrease in viscosity of the composition over time is likely to occur, especially at high temperatures in summer. If the viscosity of the composition decreases with time, there is a concern that the coating amount may become uneven and the quality of the product may fluctuate. Therefore, an adhesive composition capable of reducing the decrease in viscosity with time as much as possible is desired.

An object of the present invention is to provide an adhesive composition capable of reducing the decrease in viscosity with time as much as possible.

As a result of diligent studies on the above problems, the present inventors have determined that the adhesive composition contains component (A): carboxymethyl cellulose or a salt thereof, and component (B): anion-modified cellulose nanofibers. We have found that the above problems can be solved, and have completed the present invention.
That is, the present inventors provide the following [1] to [9].
[1] An adhesive composition containing component (A): carboxymethyl cellulose or a salt thereof, and component (B): anion-modified cellulose nanofibers.
[2] The adhesive composition according to the above [1], which further contains the component (C): an acrylic polymer.
[3] The component (C) is polyacrylic acid, polymethacrylic acid, sodium polyacrylic acid, polyacrylic acid copolymer, polymethacrylic acid copolymer, sodium polyacrylate copolymer, polyacrylic acid ester, and the like. The adhesive composition according to the above [2], which is at least one selected from the group consisting of the polyacrylic acid ester copolymer and the polyacrylic acid ester copolymer.
[4] Any of the above [1] to [3], wherein the component (B) contains cellulose oxide nanofibers, and the amount of carboxy groups of the cellulose oxide nanofibers is 0.60 to 2.0 mmol / g. The adhesive composition described in Crab.
[5] The above [1] to [3], wherein the component (B) contains carboxymethylated cellulose nanofibers, and the degree of carboxymethyl substitution of the carboxymethylated cellulose nanofibers is 0.010 to 0.50. ]. The adhesive composition according to any one of.
[6] The adhesive composition according to any one of the above [1] to [5], wherein the thinning ratio represented by the following formula (1) is 55% or less.
(1): ((B-type viscosity of the adhesive composition immediately after preparation)-(B-type viscosity of the adhesive composition after storage at 40 ° C. for 14 days)) / (B-type viscosity of the adhesive composition immediately after preparation) Viscosity) x 100
(In the above formula (1), the B-type viscosity is a value measured under the conditions of 25 ° C. and 60 rpm.)
[7] A step of dissolving at least component (A): carboxymethyl cellulose or a salt thereof in water, then adding component (B): anion-modified cellulose nanofibers and stirring, or component (B): anion-modified cellulose nano. The step of adding and dissolving at least the component (A): carboxymethyl cellulose or a salt thereof after adding the fiber to water and stirring is included, and the stirring is carried out at a stirring rate of 30 to 5000 rpm for 5 to 180 minutes. A method for producing an adhesive composition, which is agitated.
[8] A tail seal paste using the adhesive composition according to any one of the above [1] to [6].
[9] A roll paper having a sealing portion with the tail seal glue according to the above [8].

According to the present invention, it is possible to provide an adhesive composition capable of reducing the decrease in viscosity with time as much as possible.

Hereinafter, the present invention will be described in detail according to the preferred embodiment thereof. In this specification, the notation of "AA to BB" (A and B mean numbers) means AA or more and BB or less.

[1. Adhesive composition]
The adhesive composition of the present invention comprises a component (A): carboxymethyl cellulose or a salt thereof (hereinafter, also referred to as “component (A)”) and a component (B): anion-modified cellulose nanofiber (hereinafter, “component (B)”). ) ”) And. Further, the adhesive composition of the present invention preferably further contains a component (C): an acrylic polymer (hereinafter, also referred to as “component (C)”).
Since the adhesive composition of the present invention contains the component (A), it can impart the property of having a strong adhesive force at the time of adhesion and a weak adhesive force at the time of use. Since the adhesive composition of the present invention contains the component (B), the decrease in viscosity with time can be made as small as possible. Further, when the adhesive composition of the present invention contains the component (C), it is possible to impart adhesiveness at the time of adhesion while particularly exerting the effect of the present invention.

[1-1. Ingredient (A)]
The component (A) is carboxymethyl cellulose or a salt thereof. Carboxymethyl cellulose or a salt thereof has a structure in which a hydroxyl group in a glucose residue constituting cellulose is substituted with a carboxymethyl ether group. Examples of the salt of carboxymethyl cellulose include metal salts such as sodium carboxymethyl cellulose. Carboxymethyl cellulose of component (A) is a kind of water-soluble polymer.
In the present specification, "cellulose" means a polysaccharide having a structure in which D-glucopyranose (hereinafter, also referred to as "glucose residue") is linked by β-1,4-bonds. Cellulose is generally classified into natural cellulose, regenerated cellulose, fine cellulose, microcrystalline cellulose excluding amorphous regions, etc., based on the origin, manufacturing method, and the like.

Carboxymethyl cellulose or a salt thereof can be prepared by a conventionally known method. For example, carboxymethyl cellulose or a salt thereof can be prepared by using a cellulose raw material as a starting material, mixing it with a mercerizing agent in a solvent to perform a mercerization treatment, and then performing an etherification reaction with a carboxymethylating agent. ..

Examples of the cellulose raw material include natural cellulose, regenerated cellulose, and fine cellulose.
Examples of natural cellulose include cellulose produced by microorganisms such as bleached or unbleached pulp, purified linters, and acetic acid bacteria. The raw material of the bleached or unbleached pulp is not particularly limited, and examples thereof include wood, cotton, straw, and bamboo. The method for producing bleached or unbleached pulp is also not particularly limited, and a mechanical method, a chemical method, or a method in which a mechanical method and a chemical method are combined is exemplified. Examples of bleached or unbleached pulp include mechanical pulp, chemical pulp, crushed wood pulp, sulfite pulp, kraft pulp, and papermaking pulp. Further, as the bleached or unbleached pulp, dissolved pulp which is a main raw material such as artificial fiber and cellophane, which is chemically refined and mainly dissolved in a chemical and used, is also exemplified.
Examples of the regenerated cellulose include regenerated cellulose obtained by dissolving cellulose in a solvent such as a copper ammonia solution, a cellulose zantate solution, or a morpholine derivative and spinning it again.
As the fine cellulose, a fine cellulose or cellulose-based material obtained by depolymerizing a cellulosic material such as natural cellulose or regenerated cellulose by acid hydrolysis, alkali hydrolysis, enzymatic decomposition, blasting treatment, vibration ball mill treatment, etc. Examples thereof include fine cellulose obtained by mechanical treatment.

As the solvent, for example, a mixed solvent of one kind alone or two or more kinds of lower alcohols (methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tertiary butyl alcohol, etc.) and water is used. Can be used.
The mixing ratio of the lower alcohol is usually 60 to 95% by mass. The amount of the solvent used is usually 3 to 20 times that of the cellulose raw material in terms of mass.

As the mercerizing agent, for example, alkali metal hydroxides (sodium hydroxide, potassium hydroxide) can be used. The amount of the mercerizing agent used is 0.5 to 20 times the molar amount per glucose residue of the starting material.

The reaction temperature of the mercerization treatment is usually 0 to 70 ° C, preferably 10 to 60 ° C. The reaction time is usually 15 minutes to 8 hours, preferably 30 minutes to 7 hours.

As the carboxymethylating agent, for example, monochloroacetic acid or sodium monochloroacetate can be used. The amount of the carboxymethylating agent used is 0.05 to 2.0 times in terms of molar amount per glucose residue of the starting material.

The reaction temperature of the etherification reaction is usually 30 to 90 ° C, preferably 40 to 80 ° C. The reaction time is usually 30 minutes to 10 hours, preferably 1 to 4 hours.

A known method may be used to increase the purity of carboxymethyl cellulose or a salt thereof. For example, carboxy is obtained by purifying to a pure content of 99% using a solvent (one type alone or a mixed solvent of two or more types of lower alcohol and water) 3 to 20 times in terms of mass, and then drying. The purity of methyl cellulose or a salt thereof can be increased.
Examples of the lower alcohol include those exemplified for the above solvent.

Purified carboxymethyl cellulose or a salt thereof may be finely pulverized and / or classified by mechanical treatment for the purpose of uniform mixing with other components. As a specific example of mechanical processing, the cutting type mill can be used alone, or the cutting type mill can be used in combination with the impact type mill and / or the airflow type mill, and the same model can be used for several stages of processing. ..

Cutting mills include, for example, mesh mills (Horai), Atoms (Yamamoto Hyakuba), knife mills (Palman), granulators (Herbolt), and rotary cutter mills (Nara Machinery). Can be mentioned.
Impact mills include, for example, Palperizer (manufactured by Hosokawa Micron), Fine Impact Mill (manufactured by Hosokawa Micron), Super Micron Mill (manufactured by Hosokawa Micron), Sample Mill (manufactured by Seishin), Tornado Mill (manufactured by Nikkiso Co., Ltd.), Turbo Mill. (Turbo Industry Co., Ltd.), Bevel Impactor (Aikawa Iron Works Co., Ltd.).
Examples of the airflow type mill include CGS type jet mill (manufactured by Mitsui Mining Co., Ltd.), jet mill (manufactured by Sansho Industry Co., Ltd.), Ebara Jet Micronizer (manufactured by Ebara Corporation), and selenium mirror (manufactured by Masuyuki Sangyo Co., Ltd.). Be done.
Examples of the medium mill include a vibrating ball mill.

Further, the purified carboxymethyl cellulose or a salt thereof may be treated with a wet pulverizer. Examples of the wet crusher include a mass colloider (manufactured by Masuyuki Sangyo Co., Ltd.), a homogenizer, and a high-pressure homogenizer.

In the dry pulverization step, by providing a classification step after pulverization, it is possible to separate the fine portion and the coarsely crushed portion. The classification step can also be set for the dried product after wet pulverization or drying of the ground product.

Carboxymethyl cellulose or a salt thereof may be a commercially available product. Examples of commercially available products include the trade name "Sunrose" (sodium salt of carboxymethyl cellulose) manufactured by Nippon Paper Industries, Ltd.

The degree of carboxymethyl substitution per glucose residue of carboxymethyl cellulose or a salt thereof is preferably in the range of 0.40 to 2.0, more preferably in the range of 0.40 to 1.6, and is 0. It is more preferably in the range of .60 to 1.6, and even more preferably in the range of more than 1.0 and 1.6 or less. Having the degree of carboxymethyl substitution per glucose residue in such a range can ensure solubility in water and prevent the adhesive composition from becoming excessively thickened.

The degree of carboxymethyl substitution can be calculated as follows. Weigh approximately 2.0 g of the sample and place it in an Erlenmeyer flask with a 300 mL stopper. 100 mL of a solution prepared by adding 100 mL of special grade concentrated nitric acid to 1000 mL of methanol is added and shaken for 3 hours to desalinate the carboxymethyl cellulose salt (CMC) into acid-type carboxymethyl cellulose (hereinafter, also referred to as “acid-type CMC”). To do. Weigh 1.5 to 2.0 g of dry acid-type CMC and put it in an Erlenmeyer flask with a 300 mL stopper. Wet the acid-type CMC with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours. Using phenolphthalein as an indicator _{, excess NaOH can be back titrated with 0.1 N H 2} SO ₄ and the degree of carboxymethyl substitution can be calculated by the following formula.
A = [(100 x F-0.1N H ₂ SO ₄ (mL) x F') x 0.1] / (absolute dry mass (g) of acid-type CMC)
Carboxymethyl substitution degree = 0.162 × A / (1 to 0.058 × A)
A: 1N NaOH amount (mL) required to neutralize 1 g of acid-type CMC
F': 0.1N H ₂ SO ₄ factor F: 0.1N NaOH factor

The content of the component (A) is preferably 0.001 to 5.0% by mass, more preferably 0.01 to 3.0% by mass, and further preferably 0.1 to 2.0% by mass with respect to the composition. preferable. Ingredient (A)
When the content of is 0.001% by mass or more, it is possible to impart the property that the adhesive force is strong at the time of adhesion and the adhesive force is weak at the time of use. Further, when the content of the component (A) is 5.0% by mass or less, the decrease in viscosity with time due to the combined use of the component (B) can be minimized.

The component (A) may be used alone or in combination of two or more different in carboxymethyl substitution degree, molecular weight and the like.

[1-2. Ingredient (B)]
The component (B) is an anion-modified cellulose nanofiber. The "anion-modified cellulose nanofiber" is a fine fiber obtained by defibrating an anion-modified cellulose fiber in which an anionic group is introduced into a cellulose molecular chain until the fiber diameter reaches a nanoscale. Hereinafter, "cellulose nanofiber" may be abbreviated as "CNF".
Examples of the anion-modified cellulose fiber include carboxylated (oxidized) cellulose fiber, carboxymethylated cellulose fiber, phosphoric acid esterified cellulose fiber, and phosphite esterified cellulose fiber. By defibrating these, oxidized cellulose nanofibers, carboxymethylated cellulose nanofibers, phosphoric acid esterified cellulose nanofibers, and phosphite esterified cellulose nanofibers can be obtained, respectively. Of these, carboxylated (oxidized) cellulose nanofibers and carboxymethylated cellulose nanofibers are preferable.

In the present specification, "CNF" refers to fine fibers in which pulp or the like, which is a raw material for cellulose, is refined to the nanometer level and has a fiber diameter of about 3 to 500 nm. For the average fiber diameter and average fiber length of cellulose nanofibers, the fiber diameter and fiber length obtained from the results of observing each fiber using an atomic force microscope (AFM) or a transmission electron microscope (TEM) shall be averaged. Can be obtained by. Cellulose nanofibers can be obtained by applying mechanical force to the pulp to make it finer, or carboxylated cellulose fibers (hereinafter, also referred to as "oxidized cellulose fibers"), carboxymethylated cellulose fibers, and phosphoric acid esterification. It can be obtained by defibrating anion-modified cellulose fibers such as cellulose fibers and phosphite esterified cellulose fibers. The average fiber length and average fiber diameter of the fine fibers can be adjusted by oxidation treatment and defibration treatment.

The average aspect ratio of cellulose nanofibers is usually 50 or more. The upper limit is not particularly limited, but is usually 1000 or less. The average aspect ratio can be calculated by the following formula:
Aspect ratio = average fiber length / average fiber diameter

The type of cellulose used as a raw material for cellulose nanofibers (hereinafter, also referred to as “cellulose raw material”) is not particularly limited, and for example, plants (for example, wood, bamboo, hemp, jute, kenaf, agricultural waste products, cloth, pulp (for example) Unbleached coniferous kraft pulp (NUKP), bleached coniferous kraft pulp (NBKP), unbleached broadleaf kraft pulp (LUKP), bleached broadleaf kraft pulp (LBKP), unbleached coniferous sulphite pulp (NUSP), bleached coniferous sulphite pulp (NUSP) Use cellulose derived from NBSP), thermomechanical pulp (TMP), recycled pulp, used paper, etc.), animals (eg squirrels), algae, microorganisms (eg acetic acid bacteria (acetobacter)), microbial products, etc. It is preferably a cellulose fiber derived from a plant or a microorganism, and more preferably a cellulose fiber derived from a plant.

The number average fiber diameter of the cellulose raw material is not particularly limited. In the case of softwood kraft pulp, which is a general pulp, it is about 30 to 60 μm, and in the case of hardwood kraft pulp, it is about 10 to 30 μm. In the case of other pulp, the one that has undergone general purification is about 50 μm. For example, when a chip or the like having a size of several cm is purified, it is preferable to perform mechanical treatment with a dissociator such as a refiner or a beater to adjust the size to about 50 μm.

[Chemical denaturation]
By introducing an anionic group into the above-mentioned cellulose raw material, an anion-modified cellulose fiber is obtained. The method for introducing an anionic group is not particularly limited, and examples thereof include a method for introducing an anionic group into the pyranose ring of cellulose by an oxidation or substitution reaction. Specifically, a reaction that oxidizes the hydroxyl group of the pyranose ring to convert it into a carboxy group, or a reaction that introduces a carboxymethyl group, a phosphoric acid ester group, or a carboxylic acid ester group by a substitution reaction with respect to the pyranose ring. Can be mentioned.

[Carboxymethylation]
As described above, carboxymethylation can be mentioned as an example of anion denaturation. The carboxymethylated cellulose fiber, which is an example of the anion-modified cellulose fiber, may be obtained by carboxymethylating the above-mentioned cellulose raw material by a known method, or may be a commercially available product. In either case, the degree of carboxymethyl substitution of cellulose per anhydrous glucose unit is 0.010 to 0.50, preferably 0.01 to 0.44, and more preferably 0.02 to 0.40. , 0.10 to 0.30 is more preferable.
If the degree of carboxymethyl substitution exceeds 0.50, it becomes soluble in a medium such as water, and the fibrous shape may not be maintained.
The degree of carboxymethyl substitution of the carboxymethylated cellulose fiber is the same as the degree of carboxymethyl substitution of the carboxymethylated cellulose nanofiber.

The degree of carboxymethyl substitution of carboxymethylated cellulose fibers can be measured by the following methods:
Weigh approximately 2.0 g of carboxymethylated cellulose fiber (absolutely dry) and place in a 300 mL Erlenmeyer flask with a stopper. Add 100 mL of methanol nitrate (a solution of 1000 mL of methanol plus 100 mL of special grade concentrated nitric acid) and shake for 3 hours to acidify carboxymethylated cellulose fibers (hereinafter, also referred to as "CM-modified cellulose fibers") in the form of salts. Convert to CM-ized cellulose fiber. Weigh 1.5 to 2.0 g of acid-type CM-formed cellulose fiber (absolutely dry) and place it in an Erlenmeyer flask with a 300 mL stopper. Wet the acid-type CM-formed cellulose fibers with 15 mL of 80 mass% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours. Excess NaOH is back titrated with _{0.1 N H 2} SO ₄ using phenolphthalein as an indicator. The carboxymethyl degree of substitution (DS) is calculated by the following equation:
A = [(100 x F'-(0.1 N H ₂ SO ₄ ) (mL) x F) x 0.1] / (absolute dry mass (g) of acid-type CM-formed cellulose fiber)
DS = 0.162 × A / (1-0.058 × A)
A: 1N NaOH amount (mL) required to neutralize 1 g of acid-type CM-formed cellulose fiber
F: 0.1N H ₂ SO ₄ factor F': 0.1N NaOH factor.

The following methods can be mentioned as an example of the method for producing the carboxymethylated cellulose fiber:
3 to 20 times as much water and / or lower alcohol (eg, water, methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butyl alcohol, isobutyl alcohol, tertiary butyl) as a solvent in the cellulose raw material. Alcohol) is added alone or as a mixed medium of two or more. When a lower alcohol is mixed with the solvent, the mixing ratio of the lower alcohol is preferably 60 to 95% by mass.
Here, as a mercerizing agent, an alkali metal hydroxide (for example, sodium hydroxide, potassium hydroxide) of 0.5 to 20 times in terms of molar amount is added per anhydrous glucose residue of the cellulose raw material. The cellulose raw material, the solvent, and the mercerizing agent are mixed, and the reaction temperature is 0 to 70 ° C. (preferably 10 to 60 ° C.), and the reaction time is 15 minutes to 8 hours (preferably 30 minutes to 7 hours). I do. Then, a carboxymethylating agent (for example, monochloroacetic acid or a salt thereof) is added 0.05 to 10.0 times in terms of molar amount per glucose residue, and the reaction temperature is 30 to 90 ° C. (preferably 40 to 80 ° C.). ), And the reaction time is 30 minutes to 10 hours (preferably 1 to 4 hours), and the etherification reaction is carried out.

"Carboxymethylated cellulose fiber", which is a kind of anion-modified cellulose used for preparing anion-modified CNF, refers to a fiber in which at least a part of the fibrous shape is maintained even when dispersed in water. Therefore, it is distinguished from carboxymethyl cellulose, which is one of the above-mentioned water-soluble polymers. When the aqueous dispersion of "carboxymethylated cellulose fiber" is observed with an electron microscope, a fibrous substance can be observed. On the other hand, when observing the aqueous dispersion of carboxymethyl cellulose, which is a kind of water-soluble polymer, no fibrous substance is observed. Further, in the "carboxymethylated cellulose fiber", the peak of the cellulose type I crystal can be observed when measured by X-ray diffraction, but the cellulose type I crystal is not observed in the water-soluble polymer carboxymethyl cellulose.

[Carboxing (oxidation)]
As an example of anion denaturation, carboxylation (also called oxidation) can be mentioned. Carboxylation refers to a reaction in which the hydroxyl group of the pyranose ring of cellulose is oxidized to a carboxy group (-COOH (acid type) or -COOM (metal salt type) (M is a metal ion)). .. In the present specification, the anion-modified cellulose fiber obtained by carboxylation is also referred to as a carboxylated cellulose fiber or an oxidized cellulose fiber.
The carboxylated cellulose fiber can be obtained by carboxylating (oxidizing) the above-mentioned cellulose raw material by a known method.

The amount of carboxy groups in the carboxylated cellulose fiber is not particularly limited, but is preferably adjusted to 0.6 to 3.0 mmol / g with respect to the absolute dry mass of the carboxylated cellulose fiber. It is more preferable to adjust the concentration to 1.0 to 2.0 mmol / g. The amount of carboxy group can be adjusted by controlling the type and amount of the oxidizing agent, the temperature and time during the oxidation reaction, and the like.
The carboxy group amount of the carboxylated cellulose fiber is the same as the carboxy group amount of the carboxylated cellulose nanofiber.

The amount of carboxy group in the carboxylated cellulose fiber can be measured by the following method:
Prepare 60 ml of a 0.5 mass% slurry (medium: water) of carboxylated cellulose fibers, and add a 0.1 M hydrochloric acid aqueous solution to adjust the pH to 2.5. From the amount of sodium hydroxide (a) consumed in the neutralization step of a weak acid in which a change in electrical conductivity is gradual, the electrical conductivity is measured by dropping a 0.05 N sodium hydroxide aqueous solution until the pH reaches 11. , Calculated using the following formula:
Amount of carboxy group [mmol / g carboxylated cellulose fiber] = a [ml] × 0.05 / mass of carboxylated cellulose fiber [g].

As an example of the carboxylation (oxidation) method, a cellulose raw material is oxidized in water using an oxidizing agent in the presence of an N-oxyl compound and a compound selected from the group consisting of bromide, iodide and a mixture thereof. There are ways to do this. This oxidation reaction, C6-position primary hydroxyl groups of the glucopyranose ring of the cellulose surface is selectively oxidized, and an aldehyde group on the surface, a carboxy group (-COOH) or carboxylate groups (-COO ^-) and cellulosic fibers having a Can be obtained. The concentration of the cellulose raw material in water during the reaction is not particularly limited, but is preferably 5% by mass or less.

The N-oxyl compound is a compound capable of generating a nitroxy radical. As the N-oxyl compound, any compound can be used as long as it is a compound that promotes the desired oxidation reaction. For example, 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) and its derivative (for example, 4-hydroxy TEMPO) can be mentioned. The amount of the N-oxyl compound used is not particularly limited as long as it is a catalytic amount capable of oxidizing the cellulose raw material. For example, 0.01 to 10 mmol is preferable, 0.01 to 1 mmol is more preferable, and 0.05 to 0.5 mmol is further preferable, with respect to 1 g of an absolute dry cellulose raw material. Further, it is preferably about 0.1 to 4 mmol / L with respect to the entire reaction solution.

The bromide is a compound containing bromine, and examples thereof include an alkali metal bromide that can be dissociated and ionized in water. Further, the iodide is a compound containing iodine, and an example thereof includes an alkali metal iodide. The amount of bromide or iodide used can be selected within a range in which the oxidation reaction can be promoted. The total amount of bromide and iodide is, for example, preferably 0.1 to 100 mmol, more preferably 0.1 to 10 mmol, still more preferably 0.5 to 5 mmol, based on 1 g of an absolute dry cellulose raw material.

As the oxidizing agent, known ones can be used, and for example, halogens, hypochlorous acids, hypochlorous acids, perhalogenic acids or salts thereof, halogen oxides, and peroxides can be used. Of these, sodium hypochlorite, which is inexpensive and has a low environmental impact, is preferable. The appropriate amount of the oxidizing agent to be used is, for example, preferably 0.5 to 500 mmol, more preferably 0.5 to 50 mmol, still more preferably 1 to 25 mmol, still more preferably 3 to 10 mmol, based on 1 g of an absolute dry cellulose raw material. More preferred. Further, for example, 1 to 40 mol is preferable with respect to 1 mol of the N-oxyl compound.

Oxidation of the cellulose raw material tends to proceed efficiently even under relatively mild conditions. Therefore, the reaction temperature may be 4 to 40 ° C., or may be room temperature of about 15 to 30 ° C. As the reaction progresses, a carboxy group is generated in the cellulose chain, so that the pH of the reaction solution is lowered. In order to allow the oxidation reaction to proceed efficiently, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to maintain the pH of the reaction solution at 8 to 12, preferably about 10 to 11. Water is preferable as the medium in the reaction solution because it is easy to handle and side reactions are unlikely to occur.
The reaction time in the oxidation reaction can be appropriately set according to the degree of progress of oxidation, and is usually about 0.5 to 6 hours, for example, about 0.5 to 4 hours.

The oxidation reaction may be carried out in two steps. For example, by oxidizing the oxidized cellulose fibers obtained by filtration after the completion of the first-stage reaction again under the same or different reaction conditions, the reaction is not inhibited by the salt produced as a by-product in the first-stage reaction. Oxidation can proceed efficiently.

Another example of the carboxylation (oxidation) method is a method of oxidizing by contacting a gas containing ozone with a cellulose raw material. By this oxidation reaction, the hydroxyl groups at at least the 2nd and 6th positions of the glucopyranose ring are oxidized to the carboxy group, and the cellulose chain is decomposed.
Ozone concentration in the ozone containing gas is preferably ^{50~250g / m 3, 50~220g / m} 3 and more preferably. The amount of ozone added to the cellulose raw material is preferably 0.1 to 30 parts by mass, more preferably 5 to 30 parts by mass, when the solid content of the cellulose raw material is 100 parts by mass. The ozone treatment temperature is preferably 0 to 50 ° C, more preferably 20 to 50 ° C. The ozone treatment time is not particularly limited, but is about 1 to 360 minutes, preferably about 30 to 360 minutes. When the ozone treatment conditions are within these ranges, it is possible to prevent the cellulose from being excessively oxidized and decomposed, and the yield of the oxidized cellulose fiber becomes good.

After the ozone treatment, the additional oxidation treatment may be performed 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, persulfate, and peracetic acid. For example, the additional oxidation treatment can be performed by dissolving these oxidizing agents in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and immersing the cellulose raw material in the solution.

[Esterification]
Esterification can be mentioned as an example of anion denaturation. As an example of esterification, introduction of a phosphoric acid group or a phosphorous acid group into a cellulose raw material can be mentioned. In the present specification, the anion-modified cellulose fiber obtained by introducing a phosphorous acid group is referred to as a phosphorous acid esterified cellulose fiber, and the anion-modified cellulose fiber obtained by introducing a phosphorous acid group is referred to as a phosphite esterified cellulose fiber. Are collectively referred to as esterified cellulose fibers.

Examples of the method for producing a phosphoric acid esterified cellulose fiber include a method of mixing a powder or an aqueous solution of a compound having a phosphoric acid group with a cellulose raw material or a slurry thereof. Compounds having a phosphoric acid group include phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium metaphosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and phosphorus. Trisodium acid acid, potassium pyrophosphate, potassium metaphosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, ammonium metaphosphate, etc. can be mentioned, and these can be used alone or 2 You may mix more than seeds and use.

The addition ratio of the compound having a phosphoric acid group to the cellulose raw material is preferably 0.1 to 500 parts by mass, preferably 1 to 400 parts by mass, in terms of the addition amount in terms of phosphorus element with respect to 100 parts by mass of the solid content of the cellulose raw material. Is more preferable, and 2 to 200 parts by mass is further preferable. The reaction temperature is preferably 0 to 95 ° C, more preferably 30 to 90 ° C. The reaction time is not particularly limited, but is about 1 to 600 minutes, more preferably 30 to 480 minutes. The obtained suspension of phosphoric acid esterified cellulose fibers is preferably dehydrated and then heat-treated at 100 to 170 ° C. from the viewpoint of suppressing hydrolysis of cellulose. The degree of phosphoric acid group substitution per glucose unit of the phosphoric acid esterified cellulose fiber is preferably 0.001 or more and less than 0.40.

As a method for producing a phosphorous acid esterified cellulose fiber, an alkali metal ion-containing substance and an additive (A) consisting of at least one of a phosphorous acid and a phosphorous acid metal salt are added to a cellulose raw material or a slurry thereof. Examples thereof include a method of adding (preferably sodium hydrogen phosphite) and heating to introduce an ester group of phosphorous acid containing a cation consisting of an inorganic substance into a cellulose fiber. It is possible to add an additive (B) consisting of at least one of urea and a urea derivative and heat it to introduce an ester group and a carbamate group of phosphorous acid containing a cation consisting of an inorganic substance into the cellulose fiber. preferable.
As the alkali metal ion-containing substance, for example, hydroxides, metal sulfates, metal nitrates, metal chloride salts, metal phosphates, metal phosphites, and metal carbonates can be used. However, metal phosphite salts that also serve as the additive (A) are preferable, and sodium hydrogen phosphate is more preferable.

The additive (A) consists of at least one of phosphites and phosphite metal salts. Examples of the additive (A) include phosphite, sodium hydrogen phosphite, ammonium hydrogen phosphite, potassium hydrogen phosphite, sodium dihydrogen phosphite, sodium phosphite, lithium phosphite, and sub-phosphate. Phosphoric acid compounds such as potassium phosphate, magnesium phosphite, calcium phosphite, triethyl phosphite, triphenyl phosphite, and pyrophosphite can be used. Each of these phosphorous acids or phosphorous acid metal salts can be used alone or in combination of two or more. However, sodium hydrogen phosphate, which also serves as an alkali metal ion-containing substance, is preferable.
The amount of the additive (A) added is preferably 1 to 10,000 g, more preferably 100 to 5,000 g, and further preferably 300 to 1,500 g with respect to 1 kg of the cellulose raw material.

The additive (B) consists of at least one of urea and a urea derivative. As the additive (B), for example, urea, thiourea, biuret, phenylurea, benzylurea, dimethylurea, diethylurea, and tetramethylurea can be used. These ureas or urea derivatives can be used alone or in combination of two or more. However, it is preferable to use urea.
The amount of the additive (B) added is preferably 0.01 to 100 mol, more preferably 0.2 to 20 mol, and further preferably 0.5 to 10 mol with respect to 1 mol of the additive (A). is there.

The reaction temperature is preferably 100 to 200 ° C, more preferably 100 to 180 ° C. The reaction time is not particularly limited, but is about 10 to 180 minutes, more preferably 30 to 120 minutes.
Cellulose fibers into which an ester group of phosphorous acid or the like has been introduced are preferably washed prior to defibration. The degree of substitution of the phosphite group per glucose unit of the phosphite esterified cellulose fiber is preferably 0.01 or more and less than 0.23.

[Defibration]
The apparatus for defibrating the anion-modified cellulose fiber is not particularly limited, but a strong shearing force is applied to the dispersion of the anion-modified cellulose fiber by using an apparatus such as a high-speed rotary type, a colloid mill type, a high-pressure type, a roll mill type, and an ultrasonic type. It is preferable to apply force. In order to efficiently defibrate, it is preferable to use a wet high-pressure or ultra-high pressure homogenizer capable of applying a pressure of 50 MPa or more and a strong shearing force to the dispersion of the anion-modified cellulose fibers. The pressure is more preferably 100 MPa or more, and even more preferably 140 MPa or more.
The number of treatments (passes) in the defibrator may be once, twice or more, and preferably twice or more.

In the dispersion treatment, anion-modified cellulose fibers are usually dispersed in a solvent. The solvent is not particularly limited as long as it can disperse the anion-modified cellulose fiber, and examples thereof include water, an organic solvent (for example, a hydrophilic organic solvent such as methanol), and a mixed solvent thereof. Since the anion-modified cellulose fibers are hydrophilic, the solvent is preferably water.

The solid content concentration of the anion-modified cellulose fiber in the dispersion is usually 0.1% by weight or more, preferably 0.2% by weight or more, and more preferably 0.3% by weight or more. As a result, the amount of liquid becomes appropriate with respect to the amount of anion-modified cellulose fibers, which is efficient. The upper limit is usually 10% by weight or less, preferably 6% by weight or less. As a result, liquidity can be maintained.

It is also possible to pre-treat the anion-modified cellulose fibers, if necessary, prior to the defibration / dispersion treatment with a high-pressure homogenizer. The pretreatment may be performed using a mixing, stirring, emulsifying, or dispersing device such as a high-speed shear mixer.

The anion-modified cellulose fiber may be in the state of an aqueous dispersion obtained after production, or may undergo post-treatment if necessary. The post-treatment includes, for example, drying (eg, freeze-drying method, spray-drying method, shelf-stage drying method, drum drying method, belt drying method, thinly stretched drying method on a glass plate, etc., fluidized bed drying method, micro. Wave drying method, heating fan type vacuum drying method), redispersion in water (dispersing device is not limited), crushing (for example, crushing using equipment such as cutter mill, hammer mill, pin mill, jet mill). However, it is not particularly limited.

The content of the component (B) is preferably 0.0001 to 0.3% by mass, more preferably 0.0005 to 0.15% by mass, and further preferably 0.001 to 0.12% by mass with respect to 1 kg of water. preferable. When the content of the component (B) is 0.0001% by mass or more, the decrease in viscosity with time due to the use of the component (A) can be minimized. Further, when the content of the component (B) is 0.3% by mass or less, it is possible to prevent the adhesive composition from being excessively thickened.

The component (B) may be used alone or in combination of two or more.

[1-3. Ingredient (C)]
The component (C) is an acrylic polymer, and a water-soluble acrylic polymer is preferable. Examples of the acrylic polymer include polyacrylic acid, polymethacrylic acid, sodium polyacrylic acid, polyacrylic acid copolymer, polymethacrylic acid copolymer, sodium polyacrylic acid copolymer, polyacrylic acid ester, and poly. Acrylic acid ester copolymers can be mentioned.
The component (C) may be used alone or in combination of two or more.

The main monomer constituting the acrylic polymer is preferably an acrylic acid alkyl ester or a methacrylic acid alkyl ester. Examples of the alkyl group of the acrylic acid alkyl ester or the methacrylic acid alkyl ester include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and a lauryl group.
The copolymerization monomer constituting the acrylic polymer is, for example, monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; polyvalent carboxylic acids such as maleic acid, fumaric acid and itaconic acid; and acid anhydrides of polyvalent carboxylic acids. Alternatively, esters of polyvalent carboxylic acids; hydroxy group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and diethylene glycol mono (meth) acrylate; vinyl acetate, acrylic acid amide, and styrene. Be done.

The content of the component (C) is preferably 0.001 to 5% by mass, more preferably 0.01 to 3% by mass, and even more preferably 0.01 to 1% by mass with respect to the composition. When the content of the component (C) is 0.001% by mass or more, the adhesiveness at the time of adhesion can be imparted while particularly exerting the effect of the present invention. Further, when the content of the component (C) is 5% by mass or less, it is possible to prevent the adhesive composition immediately after preparation from becoming excessively high in viscosity.
When the component (C) is in the form of an aqueous solution, the content of the component (C) is the content of the solid content.

[1-4. ratio]
In the adhesive composition of the present invention, the ratio of each component (component (C) / component (A) / component (B)) is 0.001 to 5% by mass / 0.001 to the composition. 5% by mass / 0.0001 to 0.3% by mass is preferable, 0.01 to 3% by mass / 0.01 to 3% by mass / 0.0005 to 0.15% by mass is more preferable, and 0.01 to 1% is preferable. More preferably, it is mass% / 0.1 to 2 mass% / 0.001 to 0.12 mass%.
When each component is in the form of an aqueous solution, the ratio of each component is calculated by the value in terms of solid content.

[1-5. Optional ingredient]
The adhesive composition of the present invention may contain any known component as long as it does not interfere with the effects of the present invention. Optional components include, for example, preservatives, coupling agents, surfactants, antibacterial agents, fungicides, insect repellents, anti-termite agents, antioxidants, UV absorbers, antistatic agents, flame retardants, and rust preventives. , Dyes, pigments, dispersants, defoamers, antifreezes, weak acid metal salts, metal halides, bulking agents, fillers.

[1-6. Physical characteristics]
The viscosity of the adhesive composition of the present invention immediately after preparation is preferably 500 mPa · s or more, and more preferably 800 mPa · s or more. When the viscosity immediately after preparation is 500 mPa · s or more, the adhesiveness at the time of adhesion can be ensured. Further, the upper limit thereof can be appropriately set according to the usage mode of the adhesive composition of the present invention, and is preferably 1600 mPa · s or less, for example.
In the present specification, the viscosity of the adhesive composition is 25 ° C., 60 rpm, No. 3 using a TV-10 type viscometer (Toki Sangyo Co., Ltd.) as it is without adjusting the concentration of the adhesive composition. It is a value measured under the condition of using a rotor.

The thickness reduction rate of the adhesive composition of the present invention is preferably 55% or less, more preferably 45% or less. When the viscosity reduction rate is 55% or less, the decrease in viscosity with time is small, the unevenness of the coating amount is reduced, and the quality of the product can be kept constant. The lower limit of the thickness reduction rate is usually 30% or more.
In this specification, the thickness reduction rate is a value calculated by the following formula (1).
(1): ((B-type viscosity of the adhesive composition immediately after preparation)-(B-type viscosity of the adhesive composition after storage at 40 ° C. for 14 days)) / (B-type viscosity of the adhesive composition immediately after preparation) Viscosity) x 100

[2. Method for manufacturing adhesive composition]
The method for producing an adhesive composition of the present invention is a step of dissolving at least the component (A): carboxymethyl cellulose or a salt thereof in water, and then adding the component (B): anion-modified cellulose nanofibers and stirring the mixture. Component (B): Anion-modified cellulose nanofibers are added to water and stirred, and then at least component (A): carboxymethyl cellulose or a salt thereof is added and dissolved. Then, at least the component (B) is stirred at a stirring speed of 30 to 5000 rpm (preferably 1000 to 5000 rpm) for 5 to 180 minutes (preferably 10 to 100 minutes). By stirring under these conditions, the viscosity immediately after the preparation of the adhesive composition can be improved, and the decrease in viscosity with time can be reduced. When the component (C) is used, it is preferable to add it at the same time as the component (A). Further, when only the component (C) and the component (A) are dissolved, it is preferably carried out at a stirring speed of 30 to 600 rpm for 30 to 150 minutes.
The solid content concentration of the component (B) during stirring is 0.0001 to 0.3% by mass.

In the method for producing an adhesive composition of the present invention, a previously stirred component (B) may be added to the component (C) and the component (A), and the component (C) and the component (A) may be added to the component (B). May be added and then stirred.
Although the timing of addition of the optional component is not particularly limited, it is usually added at the same time as the component (C) and the component (A).

[3. Tail seal glue]
The tail seal glue of the present invention is a preferred use of the above adhesive composition. Since the adhesive composition is such that the decrease in viscosity with time is made as small as possible, the change in viscosity at the time of adhesion is small, and unevenness in the coating amount is unlikely to occur. Therefore, the quality of the product can be kept constant.
The tail seal glue is used for a sealing portion such as a winding end tip portion of a roll product such as toilet paper or kitchen paper, and a winding starting tip portion (for example, a bonding portion between a paper tube and paper at the beginning of winding). The coating type and coating amount to the roll product can be appropriately set, but usually, the coating is linearly applied in the lateral direction of the product, and the coating can be applied by a known tail sealer mechanism. When the above-mentioned adhesive composition is used as the tail seal glue of the present invention, the adhesive composition may appropriately contain various additives that can be used as components of the tail seal glue, such as preservatives and antifoaming agents.

[4. Roll paper]
The roll paper of the present invention has a sealing portion made of the above-mentioned tail seal glue. Examples of the roll paper include toilet paper, kitchen paper, paper towels, wipers and the like. The dimensions of the roll paper are not particularly limited, and the dimensions for normal use can be appropriately selected.

The roll paper can be manufactured by a method including a step of forming a sealing portion with tail seal glue on the roll paper, and other than the above steps, the roll paper can be manufactured by a known technique using, for example, a paper machine from raw material pulp in the same manner as a normal manufacturing method. An example is a method of obtaining a roll paper by obtaining a paper-made original roll. The raw material of the roll paper is not particularly limited, and examples thereof include virgin pulp (eg, NBKP, LBKP) and used paper pulp, and one or two types can be appropriately selected from these depending on the purpose. The sealing portion is usually provided at the end end portion of the winding, the adhesive portion between the paper tube and the paper at the beginning of winding, or both. The method for forming the seal portion may be a method of adhering the tail seal glue to the above-mentioned part of the roll paper, for example, a method of ejecting the tail seal glue from the spray nozzle to the roll paper, a method of adhering the tail seal glue to the plate, and then the roll paper. A method of transferring to a roll paper and a method of attaching a tail seal glue to a thread and transferring the paper to a roll paper can be mentioned.

Hereinafter, the present invention will be described in detail with reference to Examples. The following examples are for the purpose of preferably explaining the present invention, and do not limit the present invention. Unless otherwise specified, the method for measuring the physical property value or the like is the measurement method described above. Further, the “part” means a mass part unless otherwise specified.

[B-type viscosity (mPa · s)]: The B-type viscosity (60 rpm, 25 ° C.) was measured using a TV-10 type viscometer (Toki Sangyo Co., Ltd.).

[Thickness reduction rate (%)]: Calculated by the following formula (1).
(1): ((B-type viscosity of the adhesive composition immediately after preparation)-(B-type viscosity of the adhesive composition after storage at 40 ° C. for 15 days)) / (B-type viscosity of the adhesive composition immediately after preparation) Viscosity) x 100

[Carboxylic acid group amount]: The carboxy group amount was measured as follows. 60 ml of a 0.5 mass% slurry (aqueous dispersion) of cellulose oxide fibers was prepared, and a 0.1 M hydrochloric acid aqueous solution was added to adjust the pH to 2.5. A 0.05 N aqueous sodium hydroxide solution was added dropwise, and the electrical conductivity until the pH reached 11 was measured. From the amount of sodium hydroxide (a) consumed in the neutralization step of a weak acid whose electrical conductivity changes slowly, the amount of carboxy group was calculated using the following formula.
Amount of carboxy group [mmol / g cellulose oxide fiber] = a [ml] × 0.05 / mass of cellulose oxide [g]
As described in the specification, the carboxy group amount of the cellulose oxide fiber and the carboxy group amount of the cellulose oxide nanofiber are the same value.

[Average Fiber Diameter (nm)]: An aqueous dispersion of cellulose oxide nanofibers diluted so that the concentration of cellulose oxide nanofibers was 0.001% by mass was prepared. This diluted dispersion was thinly spread on a mica sample table and dried by heating at 50 ° C. to prepare a sample for observation. The cross-sectional height of the shape image observed with an atomic force microscope (AFM) was measured, and the weighted average fiber diameter was calculated.

[Average Fiber Length (nm)]: Cellular oxide nanofibers are fixed on a mica section, the fiber lengths of 200 fibers are measured using an atomic force microscope (AFM), and the length (weighted) average fiber length is measured. Was calculated. The fiber length was measured using image analysis software WinROOF (manufactured by Mitani Corporation).

[Aspect ratio]: Calculated by dividing the average fiber length by the average fiber diameter.

[Carboxymethyl Substitution Degree]: Approximately 2.0 g of the sample was precisely weighed and placed in a 300 mL Erlenmeyer flask with a stopper. 100 mL of a solution prepared by adding 100 mL of special grade concentrated nitric acid to 1000 mL of methanol was added, and the mixture was shaken for 3 hours to convert a salt (CMC) of carboxymethyl cellulose fiber into an acid type CMC. 1.5 to 2.0 g of the absolute dry acid type CMC was precisely weighed and placed in a 300 mL Erlenmeyer flask with a stopper. The acid-type CMC was moistened with 15 mL of 80% methanol, 100 mL of 0.1 N NaOH was added, and the mixture was shaken at room temperature for 3 hours. Excess NaOH was back titrated with _{0.1 N H 2} SO ₄ using phenolphthalein as an indicator. The degree of carboxymethyl substitution was calculated by the following formula.
A = [(100 x F-0.1N H ₂ SO ₄ (mL) x F') x 0.1] / (absolute dry weight of acid-type CMC (g))
Carboxymethyl substitution degree = 0.162 × A / (1 to 0.058 × A)
A: 1N NaOH amount (mL) required to neutralize 1 g of acid-type CMC
F': 0.1N H ₂ SO ₄ factor F: 0.1N NaOH factor

[Crystallinity (%)]: The crystallinity of cellulose type I was determined by measuring the X-ray diffraction of the sample. The X-ray diffraction was measured by placing the sample on a glass cell and using an X-ray diffraction measuring device (LabX XRD-6000, manufactured by Shimadzu Corporation). The crystallinity is calculated using a method such as Segal, and the diffraction intensity of the 002 surface of 2θ = 22.6 ° and 2θ = 18 with the diffraction intensity of 2θ = 10 to 30 ° in the X-ray diffraction diagram as the baseline. It was calculated by the following formula from the diffraction intensity of the amorphous part at 5.5 °.
Xc = (I _002c-Ia ) / I _002c x 100
Xc = Cellulose type I crystallinity (%)
I _002c : 2θ = 22.6 °, diffraction intensity of 002 surface Ia: 2θ = 18.5 °, diffraction intensity of amorphous part

(Production Example 1: Production of Oxidized Cellulose Nanofiber)
Add 500 g (absolutely dry) of bleached unbeaten kraft pulp (whiteness 85%) derived from softwood to 500 ml of an aqueous solution of 780 mg of TEMPO (Sigma Aldrich) and 75.5 g of sodium bromide until the pulp is uniformly dispersed. Stirred. An aqueous sodium hypochlorite solution was added to the reaction system so as to have a concentration of 6.0 mmol / g, and the oxidation reaction was started. Although the pH in the system decreased during the reaction, a 3M aqueous sodium hydroxide solution was sequentially added to adjust the pH to 10. The reaction was terminated when sodium hypochlorite was consumed and the pH in the system did not change. The mixture after the reaction was filtered through a glass filter to separate the pulp, and the pulp was thoroughly washed with water to obtain oxidized pulp (cellulose oxide fiber). The pulp yield at this time was 90%, the time required for the oxidation reaction was 90 minutes, and the amount of carboxy groups was 1.6 mmol / g.

The cellulose oxide fiber obtained in the above step is adjusted to 3.0 or 1.0% (w / v) with water and treated three times with an ultra-high pressure homogenizer (20 ° C., 150 MPa) to obtain cellulose oxide nanofibers. A dispersion was obtained. The obtained cellulose oxide nanofibers had an average fiber diameter of 3.5 nm.

(Production Example 2: Production of an aqueous dispersion of carboxymethylated cellulose nanofiber solidified product) 600 parts of isopropyl alcohol (IPA) and 10 parts of sodium hydroxide were added to 40 parts of water in a biaxial kneader whose rotation speed was adjusted to 100 rpm. An aqueous solution of sodium hydroxide dissolved in the parts was added, and 100 parts of broad-leaved pulp (LBKP manufactured by Nippon Paper Co., Ltd.) was charged by the dry mass when dried at 100 ° C. for 60 minutes. The mixture was stirred and mixed at 30 ° C. for 90 minutes to perform a mercerization treatment. Further, a solution in which 12 parts of monochloroacetic acid was dissolved in 40 parts of 90% IPA was added with stirring. After stirring for 30 minutes, the temperature was raised to 70 ° C. and a carboxymethylation reaction was carried out for 90 minutes. The concentration of IPA in the reaction medium during the carboxymethylation reaction is 94%. After completion of the reaction, neutralize with acetic acid until pH 7 and wash with hydrous methanol, drain, dry and pulverize. Carboxymethylated cellulose fiber with carboxymethyl substitution degree 0.15 and cellulose type I crystallinity 70%. Sodium salt was obtained. The effective utilization rate of the carboxymethylating agent was 73%. The method for measuring the degree of carboxymethyl substitution and the degree of crystallization of cellulose type I is as described above.

The sodium salt of the obtained carboxymethylated cellulose fiber was dispersed in water to obtain a 1.0% (w / v) aqueous dispersion. This was treated three times with a high-pressure homogenizer of 150 MPa to obtain an aqueous dispersion of carboxymethylated cellulose nanofibers.

As an anion-modified CNF, carboxymethyl cellulose (trade name: F350HC-4, viscosity (1%, 25 ° C.) of about 3000 mPa · s, carboxymethyl substitution degree of about 0. 9) was added in an amount of 40% by mass based on the anion-modified CNF (that is, the solid content of the carboxymethyl cellulose was 40 parts by mass when the solid content of the anion-modified CNF was 100 parts by mass), and the TK homomixer was added. An aqueous dispersion of anion-modified CNF was prepared by stirring at (12,000 rpm) for 60 minutes. The pH of this dispersion was about 7-8. A 0.5% aqueous sodium hydroxide solution is added to this aqueous dispersion to adjust the pH to 9, and then applied to the drum surface of a drum dryer D0405 (manufactured by Katsuragi Kogyo Co., Ltd.) to a thickness of about 100 to 200 μm. A thin film is formed, and the vapor pressure is 0.5 MPa. G, the drum was dried at a drum rotation speed of 2 rpm to obtain a dry solid of anion-modified CNF having a water content of 5% by mass.

Next, water was added to the dry solid obtained above so as to have a concentration of 1.0% (w / v), and the mixture was stirred at 3000 rpm for 1 hour using a homodisper.

(Example 1: Production of adhesive composition (1))
Acrylic polymer (trade name "Aron A-20PG-X" (manufactured by Toagosei Co., Ltd.)) 1.5 g, carboxymethyl cellulose (trade name "Sunrose F-") in 1 kg of water stirred at 600 rpm using a three-one motor. 7 g of "30HC" (manufactured by Nippon Paper Industries, Ltd.) was sequentially added and dissolved over 150 minutes. To this aqueous solution, 1 g of the cellulose oxide nanofiber solid content 1.0% product obtained in Production Example 1 was added to the aqueous solution in terms of solid content, and then stirred at 3000 rpm for 30 minutes using a homodisper to form an adhesive composition. The thing (1) was manufactured.

(Example 2: Production of adhesive composition (2))
An adhesive composition (2) was obtained in the same manner as in Example 1 except that the cellulose oxide nanofibers of Production Example 1 were changed to the carboxymethylated cellulose nanofibers of Production Example 2.

(Example 3: Production of adhesive composition (3))
The product having a solid content of 3% of cellulose oxide nanofibers obtained in Production Example 1 was used. The cellulose oxide nanofibers were added to 1 kg of water so as to have a solid content of 1 g, and the mixture was diluted and stirred at 3000 rpm for 30 minutes using a homodisper. Subsequently, 1.5 g of acrylic polymer (trade name "Aron A-20PG-X" (manufactured by Toagosei Co., Ltd.)) and carboxymethyl cellulose (trade name "Sunrose") were added to the diluted stirring solution while stirring at 100 rpm using a three-one motor. 7 g of "F-30HC" (manufactured by Nippon Paper Industries, Ltd.) was sequentially added and dissolved over 120 minutes to obtain an adhesive composition (3).

(Example 4: Production of adhesive composition (4))
The carboxymethylated cellulose nanofiber powdered product before redispersion obtained in Production Example 2 was added to 1 kg of water so as to be 1 g of solid, and diluted and stirred at 3000 rpm for 30 minutes using a homodisper. Subsequently, 1.5 g of acrylic polymer (trade name "Aron A-20PG-X" (manufactured by Toagosei Co., Ltd.)) and carboxymethyl cellulose (trade name "Sunrose") were added to the diluted stirring solution while stirring at 100 rpm using a three-one motor. 7 g of "F-30HC" (manufactured by Nippon Paper Industries, Ltd.) was sequentially added and dissolved over 120 minutes to obtain an adhesive composition (4).

(Comparative Example 1: Production of Adhesive Composition (5))
Acrylic polymer (trade name "Aron A-20PG-X" (manufactured by Toagosei Co., Ltd.)) 1.5 g, carboxymethyl cellulose (trade name "Sunrose F-30HC") in water stirred at 600 rpm using a three-one motor. (Manufactured by Nippon Paper Industries, Ltd.)) 7 g was sequentially added and dissolved over 150 minutes to obtain an adhesive composition (5).

The B-type viscosities immediately after the preparation of the adhesive compositions (1) to (5) produced in Examples 1 to 4 and Comparative Example 1, the B-type viscosities after storage at 40 ° C. for 14 days, and the viscosity reduction rate are as follows. It is shown in Table 1. The storage method is a 600 ml pack clean with a lid.

It was produced by applying each of the adhesive compositions by a method of attaching the adhesive compositions (1) to (5) produced in Examples 1 to 4 and Comparative Example 1 to a plate and then transferring them to roll paper. The adhesive strength of toilet paper (toilet roll) was measured. As for the wet adhesiveness, 5 seconds after applying the adhesive composition to the end of the roll of the toilet paper, the material was rolled for 1 m, and it was visually confirmed whether or not the tail part was peeled off. All of the prepared samples (3) were not peeled off, and those with even one peeling were marked with x. The dry adhesiveness is peeled off by its own weight when the adhesive composition is applied to the end of the roll of the toilet paper, left to stand at room temperature for 24 hours to dry, and then the adhesive composition-applied portion is grasped and hung. I confirmed whether it was. Those that did not peel off were marked with 〇, and those that did peel off were marked with x.

As can be seen from Table 1, the adhesive composition of the present invention has a viscosity reduction rate of 54% or less after being stored at 40 ° C. for 2 weeks, even though the B-type viscosity immediately after preparation is 788 mPa · s or more. Met. On the other hand, the adhesive composition to which the component (B) is not added has a viscosity reduction rate of 73% after being stored at 40 ° C. for 2 weeks, although the B-type viscosity immediately after preparation is as low as 562 mPa · s. A significant decrease was observed. Further, as can be seen from Table 1, the toilet roll coated with the adhesive composition of the present invention was excellent in wet adhesiveness at the time of applying the adhesive and dry adhesiveness after drying. The adhesive composition of the comparative example had insufficient dry adhesiveness.

Claims (9)

Ingredient (A): Carboxymethyl cellulose or a salt thereof,
Ingredient (B): An adhesive composition containing anion-modified cellulose nanofibers. The adhesive composition according to claim 1, further comprising a component (C): an acrylic polymer. The component (C) is polyacrylic acid, polymethacrylic acid, sodium polyacrylic acid, polyacrylic acid copolymer, polymethacrylic acid copolymer, sodium polyacrylic acid copolymer, polyacrylic acid ester, and polyacrylic acid. The adhesive composition according to claim 2, which is at least one selected from the group consisting of acid ester copolymers. The component (B) contains cellulose oxide nanofibers and contains.
The adhesive composition according to any one of claims 1 to 3, wherein the amount of carboxy groups of the cellulose oxide nanofibers is 0.60 to 2.0 mmol / g. The component (B) contains carboxymethylated cellulose nanofibers.
The adhesive composition according to any one of claims 1 to 3, wherein the degree of carboxymethyl substitution of the carboxymethylated cellulose nanofiber is 0.010 to 0.50. The adhesive composition according to any one of claims 1 to 5, wherein the thinning ratio represented by the following formula (1) is 55% or less.
(1): ((B-type viscosity of the adhesive composition immediately after preparation)-(B-type viscosity of the adhesive composition after storage at 40 ° C. for 14 days)) / (B-type viscosity of the adhesive composition immediately after preparation) Viscosity) x 100
(In the above formula (1), the B-type viscosity is a value measured under the conditions of 25 ° C. and 60 rpm.) A step of dissolving at least component (A): carboxymethyl cellulose or a salt thereof in water, then adding component (B): anion-modified cellulose nanofibers and stirring, or component (B): anion-modified cellulose nanofibers in water. The step of adding and dissolving at least the component (A): carboxymethyl cellulose or a salt thereof, after adding to and stirring the mixture, is included.
A method for producing an adhesive composition, wherein the stirring is performed at a stirring speed of 30 to 5000 rpm for 5 to 180 minutes. A tail seal paste using the adhesive composition according to any one of claims 1 to 6. A roll paper having a sealing portion with the tail seal glue according to claim 8.