JP7014585B2 - Water-based paint composition, film and film manufacturing method - Google Patents

Description

The present invention relates to a water-based paint composition containing cellulose nanofibers, a film made by using the water-based paint composition, and a method for producing the film.

It is expected that various convenient new materials and devices will be produced from nanotechnology, which is a technology for freely controlling substances in the nanometer region, that is, in the nanoscale range of 1 to 100 nm. In particular, nanofibers (nanofibers) are attracting a great deal of attention because when the fibers are made as thin as possible, completely new physical properties that were not found in conventional fibers are created. This nanofiber is expected to have effects such as manufacturing a high-performance filter that does not allow extremely fine foreign substances to pass through, and increasing the strength of a resin or a coating film.

Among these nanofibers, various developments and studies have been carried out on cellulose nanofibers derived from cellulose. For example, in Patent Document 1 and Patent Document 2, a part of the hydroxyl group of cellulose is carboxylated on average. Fine cellulose fibers (cellulose nanofibers) having a fiber diameter of 200 nm or less are disclosed. This cellulose nanofiber has a property of high viscosity at a low shear rate and low viscosity at a high shear rate. Therefore, for example, a paint containing cellulose nanofibers is expected to have an effect of being easy to apply at the time of coating and not dripping after coating.

Japanese Unexamined Patent Publication No. 2009-57552 Japanese Unexamined Patent Publication No. 2015-183096

However, since the gas barrier material containing cellulose nanofibers described in Patent Document 1 uses Na ions as the counterion of the carboxyl group contained in the cellulose nanofibers, the gas barrier molded body using this gas barrier material is under high humidity conditions. When exposed to, there is a risk of moisture absorption and swelling, resulting in reduced water resistance. The coating agent containing cellulose nanofibers described in Patent Document 2 aims to improve water resistance by converting 70% or more of the counterions of the carboxyl groups contained in the cellulose nanofibers into protons or ammonium ions. , The water resistance under high humidity was not sufficient.

Therefore, an object of the present invention is to provide a water-based coating composition containing cellulose nanofibers, which can obtain a film having high water resistance even under high humidity. Another object of the present invention is to provide a water-based coating composition containing cellulose nanofibers, which can obtain a film having excellent solvent resistance and gas barrier properties under high humidity. It is also an object of the present invention to provide a film obtained from this water-based coating composition and a method for producing the film.

The present invention provides:
(1) A water-based coating composition containing modified cellulose nanofibers, a polyvalent amine, and an aqueous solvent, wherein some of the hydroxyl groups in the modified cellulose nanofibers are modified by an oxidation or substitution reaction. The substituent introduced by the modification is the formula (1) :.
-COO ^- N ⁺ R ¹ R ² R ³ H (1)
(In the formula (1), R ¹ , R ² and R ³ are substituents constituting H or a monoamine having a boiling point of 110 ° C. or lower, respectively.), And the water-based coating composition comprises a structure represented by the above. Further, the polyvalent amine contains 0 to 100% by mass of a binder component with respect to the modified cellulose nanofibers, and the polyvalent amine is a water-based coating composition having a molecular chain length of 4 or more consisting of C, O, and N between both terminal amino groups. thing.
(2) In the water-based coating composition, the blending amount of the modified cellulose nanofibers is 0.5 to 30% by mass with respect to the amount of substituents introduced by the modification of the modified cellulose nanofibers. The water-based coating composition according to (1), wherein the compounding ratio of the polyvalent amine is 10 to 70% mol equivalent .
(3) The water-based coating material according to (1) or (2), wherein the modified cellulose nanofiber contains the oxidized cellulose nanofiber, and the amount of the carboxyl group of the oxidized cellulose nanofiber is 0.6 to 2.2 mmol / g. Composition.
(4) The modified cellulose nanofiber contains carboxymethylated cellulose nanofiber, and the degree of carboxymethyl substitution per glucose unit of the carboxymethylated cellulose nanofiber is 0.01 to 0.50, (1) or. The water-based coating composition according to (2).
( 5 ) The water-based paint composition according to any one of (1) to ( 4 ), further containing a preservative.
( 6 ) The water-based paint composition according to any one of (1) to ( 5 ), further comprising a rheology control agent.
( 7 ) A one-component water-based paint composition using the water-based paint composition according to any one of (1) to ( 6 ).
( 8 ) Among the components contained in the water-based paint composition according to any one of (1) to ( 6 ), a two-component water-based paint composition in which the modified cellulose nanofibers and the polyvalent amine are separated. ..
( 9 ) A film containing the water-based paint composition according to any one of (1) to ( 8 ).
( 10 ) A mixing step of obtaining the water-based coating composition according to any one of (1) to ( 8 ), a coating step of applying the water-based coating composition obtained in the mixing step to a support, and the coating. A coating film forming step of forming a coating film derived from the aqueous coating composition on the support by drying the support to which the aqueous coating composition obtained in the step is applied by heating. In the method for producing a film containing, a part of the hydroxyl group in the modified cellulose nanofiber is modified by an oxidation or substitution reaction, and the substituent introduced by the modification is the formula (1) :.
-COO ^- N ⁺ R ¹ R ² R ³ H (1)
(In the formula (1), R ¹ , R ² and R ³ are substituents constituting H or a monoamine having a boiling point of 110 ° C. or lower, respectively.) A method for producing a film.
( 11 ) The method for producing a film according to ( 10 ), wherein the support is a film-like base material, and the coating film is formed on the support in the coating film forming step to produce a coated film.
( 12 ) The film according to ( 10 ), further comprising a step of peeling the coating film formed on the support from the support, and producing a self-supporting film composed of the coating film peeled from the support. Manufacturing method.

According to the present invention, it is possible to obtain a water-based coating composition containing cellulose nanofibers, which can obtain a film having high water resistance even under high humidity. Further, the film obtained from the water-based coating composition of the present invention is excellent in solvent resistance and gas barrier property under high humidity. Further, according to the present invention, it is possible to provide a film and a method for producing a film using this water-based coating composition.

Hereinafter, the present invention will be described in detail. In the present invention, "-" includes a fractional value. That is, "X to Y" includes the values X and Y at both ends thereof.

The water-based coating composition of the present invention contains modified cellulose nanofibers, a polyvalent amine, and a water-based solvent. Further, in the modified cellulose nanofiber, a part of the hydroxyl group is modified by an oxidation or substitution reaction, and the substituent introduced by the modification is the formula (1) :.
-COO ^- N ⁺ R ¹ R ² R ³ H (1)
(In the formula (1), R ¹ , R ² and R ³ are substituents constituting H or a monoamine, respectively).

<Modified cellulose nanofiber>
In the modified cellulose nanofiber used in the present invention, a part of the hydroxyl group is modified by an oxidation or substitution reaction, and the carboxyl group contained in the substituent introduced by the modification causes an acid-base reaction with a monoamine such as ammonia to cause a monoamine. Forming salt.

The modified cellulose nanofiber used in the present invention is a fine fiber (carboxyl group-containing modified cellulose nanofiber) obtained by treating a carboxyl group-containing modified cellulose obtained by modifying a cellulose raw material with monoamine and defibrating it. Is. In the water-based coating composition of the present invention, the modified cellulose nanofiber also has a function as a binder.

<Average fiber diameter, average fiber length>
The average fiber diameter of the modified cellulose nanofibers used in the present invention is preferably 2 to 200 nm, more preferably about 4 to 100 nm. The average fiber length of the modified cellulose nanofibers used in the present invention is preferably 40 to 2,000 nm or less, and more preferably 100 to 1,000 nm. The average fiber diameter and average fiber length of cellulose nanofibers shall be the average of 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). Can be obtained by.

<Average aspect ratio>
The average aspect ratio of the modified cellulose nanofibers used in the present invention is usually 10 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

Here, the carboxyl group-containing modified cellulose means a modified cellulose having at least one carboxyl group. A carboxyl group may be bonded to the cellulose skeleton, or a group containing a carboxyl group (eg, a carboxyalkyl group such as a carboxymethyl group) may be bonded.

<Introduction of substituents including carboxyl groups>
The method for producing the modified cellulose containing a carboxyl group is not particularly limited, and examples thereof include a modification method capable of modifying a cellulose raw material and introducing a carboxyl group or a substituent containing a carboxyl group. Such a modification method is not particularly limited, and examples thereof include oxidation, etherification, and esterification. Of these, oxidation and carboxymethylation are preferable.

<Cellulose raw material>
The origin of the cellulose raw material is not particularly limited, but for example, plants (for example, wood, bamboo, hemp, jute, kenaf, farm waste, cloth, pulp (conifer unbleached kraft pulp (NUKP), conifer bleached kraft pulp (NBKP)). ), Hardwood unbleached kraft pulp (LUKP), broadleaf bleached kraft pulp (LBKP), conifer unbleached sulphite pulp (NUSP), conifer bleached sulphite pulp (NBSP) broadleaf unbleached sulphite pulp (LUSP), broadleaf bleached monkey Examples thereof include fight pulp (LBSP), thermomechanical pulp (TMP), recycled pulp, used paper, etc.), animals (for example, squirrels), algae, microorganisms (for example, acetic acid bacteria (acetobacter)), and microbial products. The cellulose raw material used in the invention may be any one of these or a combination of two or more, but is preferably a pulp raw material derived from a plant or a microorganism (for example, cellulose fiber), and more preferably a plant. It is a derived cellulose raw material (for example, cellulose fiber).

<Oxidation>
The method of oxidation is not particularly limited, but one example is oxidation 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 or a mixture thereof. There is a way to do it. According to this method, the primary hydroxyl group at the C6 position of the glucopyranose ring on the surface of cellulose is selectively oxidized to generate a group selected from the group consisting of an aldehyde group and a carboxyl group and a carboxylate group. The concentration of the cellulose raw material at the time of 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. Examples of the N-oxyl compound include 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). As the N-oxyl compound, any compound can be used as long as it is a compound that promotes the desired oxidation reaction.

The amount of the N-oxyl compound used is not particularly limited as long as it is a catalytic amount capable of oxidizing cellulose as a raw material. For example, 0.01 mmol or more is preferable, and 0.02 mmol or more is more preferable with respect to 1 g of cellulose that is completely dried. The upper limit is preferably 10 mmol or less, more preferably 1 mmol or less, still 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, still more preferably 0.02 to 0.5 mmol with respect to 1 g of the dry cellulose.

The bromide is a compound containing bromine, and examples thereof include alkali metals bromide that can be dissociated and ionized in water, such as sodium bromide. Further, the iodide is a compound containing iodine, and examples thereof include an alkali metal iodide. The amount of bromide or iodide to be used may be selected within a range that can promote the oxidation reaction. 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 dry cellulose. The upper limit is preferably 100 mmol or less, more preferably 10 mmol or less, still more preferably 5 mmol or less. Therefore, the total amount of bromide and iodide is preferably 0.1 to 100 mmol, more preferably 0.1 to 10 mmol, still more preferably 0.5 to 5 mmol with respect to 1 g of absolute dry cellulose.

The oxidizing agent is not particularly limited, and examples thereof include halogens, hypohalogenic acids, subhalogenic acids, perhalonic acids, salts thereof, halogen oxides, and peroxides. Among them, hypochlorous acid or a salt thereof is preferable, hypochlorous acid or a salt thereof is more preferable, and sodium hypochlorite is further preferable, because it is inexpensive and has a small environmental load. The amount of the oxidizing agent used is preferably 0.5 mmol or more, more preferably 1 mmol or more, still more preferably 3 mmol or more, based on 1 g of the dry cellulose. The upper limit is preferably 500 mmol or less, more preferably 50 mmol or less, still more preferably 25 mmol or less. Therefore, 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 25 mmol with respect to 1 g of the dry cellulose. When the N-oxyl compound is used, the amount of the oxidizing agent used is preferably 1 mol or more with respect to 1 mol of the N-oxyl compound. The upper limit is preferably 40 mol. Therefore, the amount of the oxidizing agent used is preferably 1 to 40 mol with respect to 1 mol of the N-oxyl compound.

Conditions such as pH and temperature during the oxidation reaction are not particularly limited, and in general, the 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 is preferably 40 ° C. or lower, more preferably 30 ° C. or lower. Therefore, 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, more preferably 10 or more. The upper limit is preferably 12 or less, more preferably 11 or less. Therefore, the pH of the reaction solution is preferably about 8 to 12, more preferably about 10 to 11. Usually, as the oxidation reaction progresses, a carboxyl group is generated in the cellulose, so that the pH of the reaction solution tends to decrease. Therefore, in order to efficiently proceed the oxidation reaction, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to maintain the pH of the reaction solution in the above range. Water is preferable as the reaction medium for oxidation 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 0.5 hours or more. The upper limit is usually 6 hours or less, preferably 4 hours or less. Therefore, the reaction time in oxidation is usually about 0.5 to 6 hours, for example, about 0.5 to 4 hours.

Oxidation may be carried out in two or more steps. 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 produced as a by-product in the first-stage reaction. Can be oxidized well.

Another example of the carboxylation (oxidation) method is a method of oxidizing by ozone treatment. By this oxidation reaction, the hydroxyl groups at at least the 2-position and the 6-position of the glucopyranose ring are oxidized, and the cellulose chain is decomposed. Ozone treatment is usually carried out by bringing a gas containing ozone into contact with a cellulose raw material.

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. Therefore, the ozone concentration in the gas is preferably 50 to 250 g / m ³ , more preferably 50 to 220 g / m ³ . The amount of ozone added is preferably 0.1 part by mass or more, and more preferably 5 parts by mass or more, based on 100 parts by mass of the solid content of the cellulose raw material. The upper limit is usually 30 parts by mass or less. Therefore, the amount of ozone added is preferably 0.1 to 30 parts by mass, and more preferably 5 to 30 parts by mass with respect to 100 parts by mass of the solid content of the cellulose raw material.

The ozone treatment temperature is usually 0 ° C. or higher, preferably 20 ° C. or higher. The upper limit is usually 50 ° C. or lower. Therefore, the ozone treatment temperature is usually 0 to 50 ° C, preferably 20 to 50 ° C. The ozone treatment time is usually 1 minute or longer, preferably 30 minutes or longer. The upper limit is usually 360 minutes or less. Therefore, the ozone treatment time 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 becomes good.

The result obtained after the ozone treatment may be further subjected to a postoxidation treatment 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 of the additional oxidation treatment include a method of 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.

The amount of carboxyl groups contained in the carboxyl group-containing modified cellulose nanofibers (cellulose oxide nanofibers) obtained by modifying the cellulose raw material by oxidation with respect to the absolute dry mass of the cellulose nanofibers is preferably 0.6 mmol / g or more. It is more preferably 0.8 mmol / g or more, still more preferably 1.0 mmol / g or more. The upper limit is preferably 2.2 mmol / g or less, more preferably 2.0 mmol / g or less, still more preferably 1.8 mmol / g or less. Therefore, 0.6 mmol / g to 2.2 mmol / g is preferable, 0.8 mmol / g to 2.0 mmol / g is more preferable, and 1.0 mmol / g to 1.8 mmol / g is further preferable.

The amount of the carboxyl group contained in the cellulose oxide nanofibers can be adjusted by controlling the amount of the oxidizing agent added and the reaction time described above.

An example of a method for measuring the amount of carboxyl groups will be described below. Prepare 60 mL of a 0.5 mass% slurry (aqueous dispersion) of cellulose oxide, add a 0.1 M hydrochloric acid aqueous solution to adjust the pH to 2.5, and then add a 0.05 N sodium hydroxide aqueous solution to bring the pH to 11. Measure the electrical conductivity until it becomes. It can be calculated from the amount of sodium hydroxide (a) consumed in the neutralization step of a weak acid with a gradual change in electrical conductivity using the following equation:
Amount of carboxyl group [mmol / g cellulose oxide or cellulose oxide nanofiber] = a [mL] × 0.05 / mass of cellulose oxide or cellulose oxide nanofiber [g]

<Carboxymethylation>
The method of carboxymethylation is not particularly limited, and examples thereof include a method of marcelifying a cellulose raw material as a bottoming raw material and then etherifying it. Examples of the solvent include water, alcohol (for example, lower alcohol) and a mixed solvent thereof. Examples of 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 is usually 60% by mass or more or 95% by mass or less, preferably 60 to 95% by mass. The amount of the solvent is usually 3 times by mass with respect to the cellulose raw material. The upper limit is not particularly limited, but is preferably 20 times by mass. Therefore, the amount of the solvent is preferably 3 to 20 times by mass.

Mercerization is usually carried out by mixing a bottoming material and a mercerizing agent. Examples of the mercerizing agent include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. The amount of the mercerizing agent used is preferably 0.5 times mol or more, more preferably 0.7 times mol or more, and further preferably 0.8 times mol or more per anhydrous glucose residue of the bottoming material. The upper limit is usually 20 times or less, preferably 10 times or less, more preferably 5 times or less, and therefore preferably 0.5 to 20 times, more preferably 0.7 to 10 times, 0. .8 to 5 times the mole is more preferable.

The reaction temperature for mercerization is usually 0 ° C. or higher, preferably 10 ° C. or higher. The upper limit is 70 ° C. or lower, preferably 60 ° C. or lower. Therefore, 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 is usually 8 hours or less, preferably 7 hours or less. Therefore, the reaction time is usually 15 minutes to 8 hours, preferably 30 minutes to 7 hours.

The etherification reaction is usually carried out by adding a carboxymethylating agent to the reaction system after mercerization. Examples of the carboxymethylating agent include sodium monochloroacetate. The amount of the carboxymethylating agent added is usually preferably 0.05 times or more, more preferably 0.5 times or more, still more preferably 0.7 times or more per glucose residue of the cellulose raw material. The upper limit is usually 10.0 times mol or less, preferably 5 times mol or less, more preferably 3 times mol or less, and therefore preferably 0.05 to 10.0 times mol, more preferably 0.5 to 5 times. It is double mol, more preferably 0.7 to 3 times mol. The reaction temperature is usually 30 ° C. or higher, preferably 40 ° C. or higher, and the upper limit is usually 90 ° C. or lower, preferably 80 ° C. or lower. Therefore, the reaction temperature is usually 30 to 90 ° C, preferably 40 to 80 ° C. The reaction time is usually 30 minutes or more, preferably 1 hour or more. The upper limit is usually 10 hours or less, preferably 4 hours or less. Therefore, the reaction time is usually 30 minutes to 10 hours, preferably 1 hour to 4 hours. If necessary, the reaction solution may be stirred during the carboxylation reaction.

The degree of carboxymethyl substitution per anhydrous glucose unit in the carboxyl group-containing modified cellulose nanofiber (carboxymethylated cellulose nanofiber) obtained by carboxymethylation is preferably 0.01 or more, more preferably 0.05 or more, and 0. It is more preferably .10 or more. The upper limit is preferably 0.50 or less, more preferably 0.40 or less, and even more preferably 0.35 or less. Therefore, 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 0.35.

Examples of the method for measuring the degree of carboxymethyl substitution per glucose unit of the carboxymethylated cellulose nanofiber include the following methods: 1) Weighing approximately 2.0 g of the carboxymethylated cellulose fiber (absolutely dry), Place in a triangular flask with a 300 mL stopper. 2) Add 100 mL of a solution prepared by adding 100 mL of special grade concentrated nitrate to 1000 mL of methanol nitrate, and shake for 3 hours to convert the carboxymethyl cellulose salt (CM-modified cellulose) into hydrogen-type CM-modified cellulose. 3) Weigh 1.5 to 2.0 g of hydrogen-type CM-formed cellulose (absolutely dry) and put it in a 300 mL Erlenmeyer flask with a stopper. 4) Wet hydrogen-type CM-formed cellulose with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours. 5) Using phenolphthalein as an indicator, back titrate excess NaOH with 0.1 N H ₂ SO ₄ . 6) The degree of carboxymethyl substitution (DS) is calculated by the following equation.

A = [(100 x F x 0.1- (0.1 N H ₂ SO ₄ ) (mL) x F') x 0.1] / (absolute dry mass (g) of hydrogen-type CM-formed cellulose)
DS = 0.162 x A / (1-0.058 x A)
A: 1N NaOH amount (mL) required to neutralize 1 g of hydrogen-type CM-formed cellulose
F': 0.1N H ₂ SO ₄ factor F: 0.1N NaOH factor

As a method for cleaning carboxyl group-containing modified cellulose such as oxidized cellulose and carboxymethylated cellulose obtained by the above method, a method for cleaning with an alkali and a salt formed, and a method for adding an acid to make a carboxylic acid for cleaning. , There is a method of adding an organic solvent to insolubilize and wash. From the viewpoint of handleability and yield, a method of adding an acid to make a carboxylic acid and washing is preferable. Water is preferable as the cleaning solvent. When recovery is performed by pickling with a washing solution having a pH value adjusted to 3, the counterion of the carboxyl group is replaced with a proton, and the metal ion can be removed.

The metal ion content contained in the carboxyl group-containing modified cellulose can be investigated by various analysis methods, but by elemental analysis of the EPMA method and the fluorescent X-ray analysis method using an electron probe microanalyzer (EPMA). You can easily check it.
In order to suppress swelling due to the ingress of water molecules, it is necessary to suppress the hydrophilicity of the counterion of the carboxyl group on the surface of the carboxyl group-containing modified cellulose. When the counterion is Na, it tends to swell due to the entry of water molecules. Therefore, it is preferable that the amount of Na is as small as possible.

<Defibration>
Next, a step of refining the carboxyl group-containing modified cellulose will be described.
As a method for refining the pickled carboxyl group-containing modified cellulose, it is first necessary to immerse the carboxyl group-containing modified cellulose in water as a dispersion medium and then adjust the pH value to 7 or more and 12 or less with an alkali. .. At this time, by using a monoamine such as ammonia as the alkali, at least a part of the carboxyl groups contained in the carboxyl group-containing modified cellulose fiber is ionically bonded to the monoamine. When the pH value is lower than 7, electrical repulsion is unlikely to occur and the solution is opaque. When the pH value is adjusted to 7 or more and 12 or less to make it finer, the carboxyl group-containing cellulose is defibrated to the nano-order from the electrostatic repulsion of the carboxyl group, and the transparency of the solution is increased.

<Monoamine>
The type of monoamine when treating the carboxyl group-containing modified cellulose with monoamine is not particularly limited, but considering the step of heating the water-based paint composition to volatilize water and monoamine outside the system, the boiling point is 110. Monoamines below ° C are preferred. Examples of monoamines include ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, n-propylamine, dipropylamine, isopropylamine, N, N-dimethylethylamine, N-ethylmethylamine, N, N-. Examples thereof include diethylmethylamine, n-butylamine, isobutylamine, tert-butylamine, n-amylamine, N-methylpentrilamine, isoamylamine, neopentylamine, etc., monoalkylamine having 5 or less carbon atoms, and 3 or less carbon atoms. It is more preferable to use the dialkylamine of the above, or a trialkylamine having 2 or less carbon atoms.

The carboxyl group-containing modified cellulose is used in the state of an aqueous dispersion dispersed in water as a dispersion medium. The solid content concentration of the carboxyl group-containing modified cellulose in the dispersion is usually 0.1% by mass or more, preferably 0.2% by mass or more, and more preferably 0.3% by mass or more. As a result, the amount of the liquid becomes appropriate with respect to the amount of the cellulose fiber raw material, which is efficient. The upper limit is usually 10% by mass or less, preferably 6% by mass or less. This makes it possible to maintain liquidity.

The apparatus used for defibration is not particularly limited, and examples thereof include high-speed rotary type, colloidal mill type, high pressure type, roll mill type, ultrasonic type and the like, and a high pressure or ultrahigh pressure homogenizer is preferable, and a wet high pressure or wet type is used. An ultrahigh pressure homogenizer is more preferred. The apparatus preferably can apply a strong shearing force to the cellulose raw material or modified cellulose (usually a dispersion). The pressure that can be applied by the device is preferably 50 MPa or more, more preferably 100 MPa or more, still more preferably 140 MPa or more. The apparatus is preferably a wet high-pressure or ultra-high pressure homogenizer capable of applying the above pressure to the cellulose raw material or modified cellulose (usually a dispersion) and applying a strong shearing force. As a result, defibration can be performed efficiently. The number of treatments (passes) in the defibrator may be once, twice or more, and preferably twice or more.

The order of the defibration treatment and the dispersion treatment is not particularly limited, and either of them may be performed first or at the same time, but it is preferable to perform the defibration treatment after the dispersion treatment. The combination of each process may be performed at least once, and may be repeated twice or more.

Prior to the defibration treatment or the dispersion treatment, a preliminary treatment may be performed as necessary. Pretreatment may be performed using a mixing, stirring, emulsifying, and dispersing device such as a high-speed shear mixer.

<Multivalent amine>
The type of polyvalent amine used in the present invention is not particularly limited, but divalent to hexavalent amines are preferable. Examples of the divalent amine include 1,2-ethylenediamine (hereinafter, may be referred to as "1,2-ethanediamine"), 1,3-propanediamine, and 1,4-butanediamine (hereinafter, "tetramethylenediamine"). (Sometimes), 1,5-pentanediamine (hereinafter sometimes referred to as "pentamethylenediamine"), 1,6-hexanediamine (hereinafter sometimes referred to as "hexamethylenediamine"), 1,7-heptane Diamine (hereinafter sometimes referred to as "heptamethylenediamine"), 1,8-octanediamine (hereinafter sometimes referred to as "octamethylenediamine"), 1,9-nonanediamine (hereinafter referred to as "nonamethylenediamine") , 1,8-Diamino-3,6-dioxaoctane, α, ω-polyetherdiamine and the like, and examples of trivalent amines include tris (2-aminoethyl) amine and diethylenetriamine (“2,” (Sometimes referred to as "2'-diaminodiamine")) The tetravalent amine is triethylenetetramine (sometimes referred to as "N, N'-di (2-aminoethyl) ethylenediamine"), and the pentavalent amine is Tetraethylenepentamine (sometimes referred to as "1,4,7,10-pentaazatridecane"), and as a hexavalent amine, pentaethylenehexamine ("1,4,7,10,13,16-hexaaza") Hexamethylene ") and the like. From the viewpoint of the length of the molecular chain, an amine having a molecular chain length of 4 or more consisting of C, O, and N between both terminal amino groups such as 1,4-butanediamine is preferable, and an amine having a molecular chain length of 4 or more is preferable, such as 1,6-hexanediamine. More than 6 amines are more preferably used.

The compounding ratio of the polyvalent amine used in the water-based coating composition of the present invention is 10 to 70% mol equivalent with respect to the amount of substituents of the modified cellulose nanofibers from the viewpoint of maintaining the strength of the coating film. It is preferably 25 to 50% mol equivalent , more preferably.

<Aqueous solvent>
The type of the aqueous solvent is not particularly limited, but water, a water-soluble organic solvent, or a mixed solvent thereof is preferable. Considering the dispersibility of the modified cellulose, water or a mixed solvent of water and a water-soluble organic solvent is preferable as the aqueous solvent. When the aqueous solvent is water, the aqueous dispersion of the modified cellulose nanofibers prepared as described above can be used as it is. Alternatively, the water dispersion may be concentrated by filtering the water dispersion.

When the aqueous solvent is used as the mixed solvent, the water-soluble organic solvent may be added to the aqueous dispersion of the modified cellulose prepared as described above, or a part of the aqueous dispersion may be replaced with the water-soluble organic solvent. For substitution, water is removed from the aqueous dispersion of the modified cellulose by drying or filtration to obtain a concentrated aqueous dispersion or a wet cake of chemically modified cellulose, and a water-soluble organic solvent is added thereto. It can be carried out.

The water-soluble organic solvent is an organic solvent that dissolves in water. Examples are methanol, ethanol, 2-propanol, butanol, glycerin, acetone, methyl ethyl ketone, 1,4-dioxane, N-methyl-2-pyrrolidone, tetrahydrofuran (THF), N, N-dimethylformamide (DMF), N. , N-dimethylacetamide, dimethyl sulfoxide (DMSO), acetonitrile, methyltriglycoldiester succinate, acetic acid and combinations thereof. Among them, lower alcohols having 1 to 4 carbon atoms such as methanol, ethanol and 2-propanol are preferable, methanol, ethanol and 2-propanol are more preferable from the viewpoint of safety and availability, and boiling point is obtained from the viewpoint of paint stability. Higher ethanol and 2-propanol are more preferable.

The amount of the water-soluble organic solvent in the mixed solvent is preferably 10% by mass or more, more preferably 50% by mass or more, still more preferably 70% by mass or more. The upper limit of the amount is not limited, but is preferably 95% by mass or less, and more preferably 90% by mass or less. Further, the aqueous solvent may contain a water-insoluble organic solvent to the extent that the effect of the invention is not impaired.

<Binder component>
The modified cellulose nanofibers contained in the water-based coating composition of the present invention have a function as a binder, but the water-based coating composition of the present invention may contain a binder component other than the modified cellulose nanofibers. In the present invention, the type of binder component used as needed is not particularly limited, but for example, a resin having a form such as a water-soluble resin, a dispersion, an emulsion, or a microgel can be used. More specifically, the water-soluble resin is exemplified as acrylic resin, alkyd resin, polyester resin, polyurethane resin, acrylic urethane resin, fluororesin, epoxy resin, epoxy acrylate resin, phenol resin, melamine resin, vinyl resin. Examples thereof include resins, polyamide resins, and cellulose-based resins. As the water-soluble resin, it is preferable to use a polyurethane resin or an acrylic urethane resin.

When a binder component other than the modified cellulose nanofibers is used, the blending ratio of the binder component in the water-based coating composition is preferably 0 to 100% by mass, more preferably 0 to 55% by mass, based on the modified cellulose nanofibers. ..

<Preservative>
In the water-based coating composition of the present invention, a preservative may be used together with the above-mentioned modified cellulose nanofibers, polyvalent amine, water-based solvent, and a binder component used as necessary.

The preservative is not particularly limited, but is not particularly limited, for example, methylparaben, ethylparaben, organic nitrogen sulfur-based compound, haloallyl sulfone compound, iodopropargyl compound, isothiazoline-based compound, phenol-based compound, triazine-based compound, propane-1. , 2-diol, etc., and may be used alone or in combination of two or more.

When a preservative is used, the blending ratio of the preservative in the water-based coating composition is preferably 0.001 to 5% by mass with respect to the total mass of the modified cellulose nanofibers and the binder component.

<Rheology control agent>
The water-based coating composition of the present invention may contain a rheology control agent. The rheology control agent is used to increase or decrease the viscosity, or has a role of lowering the surface energy to impart wettability to the substrate, imparting adhesiveness, and imparting smoothness to the surface.

Examples of the leology control agent include an alkali-soluble poly (meth) acrylic acid- (meth) acrylic acid ester copolymer and other alkali-soluble leology control agents; Leology control agent; Cellulosyl derivative-based leology control agent such as carboxylmethylcellulose, methylcellulose, hydroxyethylcellulose; Inorganic reology control agent such as silicate such as water-soluble aluminum silicate, montmorillonite, colloidal alumina; casein, sodium caseite, Protein-based rehology control agents such as ammonium caseeate; Alginic acid-based rehology control agents such as sodium alginate; Polyvinyl-based reology control agents such as polyvinyl alcohol, polyvinylpyrrolidone, and polyvinyl-benzyl ether copolymers; Sodium polyacrylate, alkali-soluble Polyacrylic acid-based rheology control agents such as type poly (meth) acrylic acid- (meth) acrylic acid ester copolymer; pluronic polyether, polyether dialkyl ester, polyether dialkyl ether, polyether urethane association group modified product, poly Polyether-based rheology control agents such as ether epoxy modified products; partial esters of vinyl methyl ether-maleic anhydride copolymers, semi-esters of allyl alcohol esters of dry oil fatty acids and maleic anhydrides, etc. Polymerization system Leology control agent; Polysiloxane type leology control agent; Fluorine type leology control agent, acetylene glycol, xanthan gum, zantane gum, starch and the like, but the present invention is not limited to such examples.

When the rheology control agent is used, the blending ratio of the rheology control agent in the water-based coating composition is preferably 0.01 to 10% by mass with respect to the total mass of the modified cellulose nanofibers and the binder component, and is 0. It is more preferably 0.01 to 5% by mass.

<Water-based paint composition>
The blending ratio of each component in the water-based coating composition of the present invention is not particularly limited, but when the blending amount of the modified cellulose nanofibers is 100% by mass, the blending ratio of the binder component is preferably from the viewpoint of barrier properties. When the content is 0 to 100% by mass, more preferably 0 to 55% by mass, and the total amount of the water-based coating composition is 100% by mass, the blending amount of the modified cellulose nanofibers is stable in dispersion of the modified cellulose nanofibers. From the viewpoint of sex, 0.5 to 30% by mass is preferable.

In the water-based coating composition of the present invention, the carboxyl group of the modified cellulose nanofiber does not react with the polyvalent amine in the system when the carboxyl group of the modified cellulose nanofiber is ionically bonded to the monoamine. Therefore, the pot life and shell life of the obtained water-based paint composition can be extended. If the modified cellulose nanofibers are not bound to monoamine, the modified cellulose nanofibers react with the polyvalent amine and crosslink by adding the polyvalent amine, so that the modified cellulose nanofibers are applied to the base material as a coating composition. It becomes difficult to do.

In the water-based coating composition of the present invention, when water and monoamines such as ammonia volatilize outside the system by heating, the carboxyl group of the modified cellulose nanofibers reacts with the polyvalent amine to form a salt and crosslink. Further heating results in the formation of amide bonds and strong cross-linking. By this reaction, the dried film obtained by using the water-based coating composition of the present invention has improved solvent resistance and gas barrier property under high humidity, and dramatically improved water resistance under high humidity. do.

The water-based paint composition of the present invention may be a one-component water-based paint composition in which a component containing the above-mentioned binder component, modified cellulose nanofibers, polyvalent amine, and water-based solvent is mixed into one, or the above-mentioned component. Of these, the modified cellulose nanofiber component and the polyvalent amine component may be separately separated and mixed at the time of use as a two-component water-based paint composition.

In the water-based coating composition of the present invention, the modified cellulose nanofibers used do not react with the polyvalent amine in the system because they are ionically bonded to the monoamine. Therefore, even when a one-component water-based paint composition is used, the shell life can be extended.

The water-based paint composition of the present invention includes known fillers, colorants such as pigments, ultraviolet absorbers, antistatic agents, and water resistant agents (within the range of types and amounts that can solve the problems of the present invention. Silane coupling agents, etc.), clay minerals (montmorillonite, etc.), cross-linking agents (additives having reactive functional groups such as epoxy groups and isocyanate groups), metal salts, colloidal silica, alumina sol, titanium oxide, etc. may be blended. can.

<Use of water-based paint composition>
The water-based coating composition of the present invention is a binder composition (water-based binder composition).

The water-based binder composition is used as a coating agent, a surface reinforcing agent, a scratch inhibitor, a rust preventive pigment / stain inhibitor / surface protectant, an antifouling treatment agent, an antifogging agent, and an antistatic agent used on the surface of a base material. It can be used as an additive thereof, and as a binder or additive for various paints. As the molded body as the base material, thin materials such as films, sheets, woven fabrics and non-woven fabrics having a desired shape and size, and three-dimensional containers such as boxes and bottles of various shapes and sizes can be used. As these molded bodies, paper, paperboard, plastic, metal (those with many holes or wire mesh-like ones mainly used as reinforcing materials), or composites thereof may be used. Among them, it is preferable to use a plant-derived material such as paper or paperboard, a biodegradable material such as biodegradable plastic, or a biomass-derived material. The molded product as the base material may have a multi-layer structure composed of the same or a combination of different materials (for example, an adhesiveness or wettability improving agent).

When plastic is used as the base material, the type thereof can be appropriately selected depending on the intended use, such as polyethylene, polypropylene and other polyolefins and cyclic polyolefins, nylon 6, nylon 66, nylon 6/10, nylon 6/12 and the like. Polyester, polyethylene terephthalate (PET), polybutylene terephthalate, aliphatic polyester, polylactic acid (PLA), polycaprolactone, polyester such as polybutylene succinate, cellophane such as cellulose, cellulose triacetate (TAC), etc. 1 or Two or more can be used.

The thickness of the molded product as the base material is not particularly limited, and may be appropriately selected so as to obtain strength according to the intended use, and can be, for example, in the range of 1 to 1000 μm. As the base material, a material containing known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, and a colorant can be used. Further, a surface modified by corona treatment, excimer light treatment, anchor coating treatment or the like to improve the adhesion to the composite coating formed on the surface can also be used.

The method for producing a coating film using the water-based coating composition of the present invention is not limited to the following, and is, for example, a comma coater, a roll coater, a reverse roll coater, a gravure coater, a micro gravure coater, and a knife coater. , Bar coater, wire bar coater, die coater, dip coater, slot die coater, spray coating, etc. The film coated with the coating material can be dried by heating to produce a coating film in which a coating film derived from the water-based coating composition is formed on the film of the base material. As means for drying the coating film, for example, an electric drying oven (natural convection type or forced convection type), a hot air circulation type drying oven, a drying oven using both far infrared heating and hot air circulation, and vacuum drying that can reduce the pressure while heating. A method using a furnace or the like can be adopted. Here, in the present invention, the thickness of the coating film after drying is not particularly limited and may be appropriately selected depending on the intended use, and can be, for example, in the range of 0.02 to 100 μm.

The heating temperature in the case of heating is preferably 110 to 200 ° C., more preferably 120 to 180 ° C. from the viewpoint that the water-based solvent and the monoamine can be sufficiently volatilized from the water-based coating composition applied to the film. The heating time is preferably 1 to 60 minutes, more preferably 2 to 30 minutes from the viewpoint of protecting the base material.

The water-based coating composition of the present invention is also suitably used in the production of self-supporting films. The method for producing a self-supporting film is not limited to the following, but for example, a comma coater, a roll coater, a reverse roll coater, a gravure coater, a micro gravure coater, a knife coater, a bar coater, a wire bar coater, a die coater, and the like. It is applied to a film as a support, a drying drum, a drying belt, etc. using a known coating method such as a dip coater, a slot die coater, or a spray coating, and when applied to the film, it is heated in a drying zone. After drying, the coating film can be peeled off to obtain a self-supporting film as a continuous film. Further, when applied to a drying drum or a drying belt, the coating film can be peeled off after being heated and dried to obtain a self-supporting film as a continuous film.

The heating temperature and heating time in the production of the self-supporting film may be the same as the temperature and time in the production of the coated film.

Here, in the present invention, the thickness of the self-supporting film is not particularly limited and may be appropriately selected depending on the intended use, and may be, for example, in the range of 2 to 200 μm.

The water-based coating composition of the present invention may be used for producing a plate-like material having a thickness larger than that of a film. The plate-shaped material may be integrated with a molded body as a base material, or may be a material in which the base material is peeled off after being heated and dried. The thickness of the plate after drying when forming a plate-like material is not particularly limited, and can be, for example, in the range of 500 to 3,000 μm.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. When the method for measuring / calculating each numerical value in each embodiment is not particularly described, the method is measured / calculated by the method described in the specification.

[Manufacturing Example 1]
500 g (absolutely dry) of bleached unbeaten kraft pulp (whiteness 85%) derived from coniferous trees, 1.95 g (0.025 mmol for 1 g of absolute dry cellulose) and 51.4 g (sodium bromide) of TEMPO (Sigma Aldrich). It was added to 500 mL of an aqueous solution in which 1 mmol) was dissolved in 1 g of absolute dry cellulose, and the mixture was stirred until the pulp was uniformly dispersed. An aqueous sodium hypochlorite solution was added to the reaction system so that the sodium hypochlorite content was 6.0 mmol / g, and the oxidation reaction was started. Although the pH in the system decreased during the reaction, 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. Hydrochloric acid is added to the mixture after the reaction to adjust the pH to 2.4, then filtered through a glass filter to separate the pulp, and the pulp is thoroughly washed with water to obtain oxidized pulp (oxidized (carboxylated) cellulose). Obtained. The pulp yield at this time was 90%, the time required for the oxidation reaction was 90 minutes, and the amount of carboxyl groups was 1.6 mmol / g.

The modified pulp obtained in the above step was adjusted to 1.0% (w / v) with water, the pH was adjusted to 8 with ammonia, and treated with an ultrahigh pressure homogenizer (20 ° C., 150 MPa) three times. An aqueous dispersion of cellulose nanofiber 1 (CNF1) containing a substituent in which carboxyl ion was ionically bonded to ammonium ion was obtained.

[Manufacturing Example 2]
In a stirrer capable of mixing pulp, 253 g of pulp (NBKP (coniferous bleached kraft pulp), manufactured by Nippon Paper Industries) by dry mass and 56.3 g of sodium hydroxide by dry mass (0.9 per glucose residue of pulp). (Double mol) was added, and water was added so that the pulp solid content was 20% (w / v). Then, after stirring at 30 ° C. for 30 minutes, 127 g (0.7 times mol per glucose residue of pulp) of sodium monochloroacetate was added. After stirring for 30 minutes, the temperature was raised to 70 ° C. and the mixture was stirred for 1 hour. Then, the reaction product was taken out, neutralized and washed to obtain a carboxylmethylated pulp having a carboxymethyl substitution degree of 0.25 per glucose unit.

The modified pulp obtained in the above step was adjusted to 1.0% (w / v) with water, the pH was adjusted to 8 with ammonia, and treated with an ultrahigh pressure homogenizer (20 ° C., 150 MPa) three times. An aqueous dispersion of cellulose nanofiber 2 (CNF2) containing a substituent in which carboxyl ion was ionically bonded to ammonium ion was obtained.

[Manufacturing Examples 3 to 22]
An aqueous dispersion of cellulose nanofibers 3 to 22 (CNF3 to 22) was obtained in the same manner as in Production Example 1 except that the chemical used for pH adjustment was changed from ammonia to the monoamine shown in Table 1.

[Manufacturing Example 23]
An aqueous dispersion of cellulose nanofibers 23 (CNF23) was obtained in the same manner as in Production Example 1 except that the chemical used for pH adjustment was changed from ammonia to sodium hydroxide.

<Preparation of water-based paint composition>
[Example 1]
1 part by mass of the cellulose nanofiber 1 produced in Production Example 1 and 0.1 part by mass of hexamethylenediamine in terms of solid content were added, and the component ratio of the solvent in the final composition was 2-propanol / water. 2-Propanol and water were added so that = 30/70, and the whole was made 100 parts by mass. Next, using a homomixer, mixing was performed at 12000 rpm for 15 minutes to obtain a water-based paint composition.

[Examples 2 to 18]
A water-based coating composition was obtained in the same manner as in Example 1 except that the cellulose nanofiber 1 was changed to the cellulose nanofibers 2 to 18.

[Examples 19 to 31]
A water-based coating composition was obtained in the same manner as in Example 1 except that hexamethylenediamine was changed to the polyvalent amine shown in Table 2 and the respective addition amounts.

[Comparative Example 1]
A water-based paint composition was obtained in the same manner as in Example 1 except that hexamethylenediamine was not added.

[Comparative Example 2]
A water-based coating composition was obtained in the same manner as in Example 1 except that the cellulose nanofiber 1 was changed to the cellulose nanofiber 23.

[Comparative Examples 3 to 6]
A water-based coating composition was obtained in the same manner as in Example 1 except that the cellulose nanofiber 1 was changed to the cellulose nanofibers 19 to 22.

[Comparative Example 7]
A water-based coating composition was obtained in the same manner as in Example 1 except that 0.1 part of hexamethylenediamine was changed to 0.05 part of 1,2-ethanediamine.

[Comparative Example 8]
A water-based coating composition was obtained in the same manner as in Example 1 except that 0.1 part of hexamethylenediamine was changed to 0.07 part of piperidine.

[Example 32]
1 part by mass of cellulose nanofiber 1 in terms of solid content, 0.1 part by mass of hexamethylenediamine in terms of solid content, preservative: 0.005 part by mass of methylparaben, urethane-associated rheology control agent Adecanol UH-420 (Made by ADEKA Co., Ltd., active ingredient amount: 30%) is weighed 0.1 parts by mass in terms of active ingredient, and water-based urethane resin emulsion (active ingredient amount 40%) is weighed by 0.43 parts by mass in terms of solid content. Then, 2-propanol and water were added so that the component ratio of the solvent in the final composition was 2-propanol / water = 30/70, and the whole was made 100 parts by mass. Next, using a homomixer, mixing was performed at 12000 rpm for 15 minutes to obtain a water-based paint composition.

[Example 33]
A water-based paint composition was obtained in the same manner as in Example 32 except that the water-based urethane resin emulsion was made up to 1.0 part.

[Example 34]
Weigh 15 parts by mass of titanium oxide, 7 parts by mass of calcium carbonate, and 20 parts by mass of water (for pigment dispersion), which are colorants, and disperse them with a bead mill to prepare a pigment dispersion with a 52.4% mass concentration. did. In 0.15 parts by mass of the obtained pigment dispersion, 1 part by mass of cellulose nanofiber 1 in terms of solid content, 0.1 part by mass of hexamethylenediamine in terms of solid content, and 0.005 parts of preservative: methylparaben. Mass, urethane-associated rheology control agent Adecanol UH-420 (manufactured by ADEKA Co., Ltd., amount of active ingredient: 30%) is 0.1 part in terms of active ingredient, and the component ratio of the solvent in the final composition is 2-propanol. 2-Propanol and water were added so that / water = 30/70, and the whole was made 100 parts by mass. Next, using a homomixer, mixing was performed at 12000 rpm for 15 minutes to obtain a water-based paint composition.

[Example 35]
A water-based paint composition was obtained in the same manner as in Example 32 except that 0.18 parts of the pigment dispersion obtained in Example 34 was added.

[Comparative Example 9]
1.5 parts by mass of water-based urethane resin emulsion, 0.0005 parts of preservative methylparaben, urethane-associated rheology control agent ADEKA NOL UH-420 (manufactured by ADEKA Corporation, active ingredient amount: 30%) A water-based coating composition was obtained in the same manner as in Example 32 except that the active ingredient conversion value was 0.1 part.

[Comparative Example 10]
The water-based urethane resin emulsion was added to 10 parts by mass in terms of solid content, and the urethane-associated rheology control agent Adecanol UH-420 (manufactured by ADEKA Corporation, active ingredient amount: 30%) was added to 0.37 parts in terms of active ingredient. A water-based paint composition was obtained in the same manner as in Comparative Example 9 except.

Using each of the water-based paint compositions thus obtained, a coating film and a self-supporting film were prepared as described below, and the water resistance, solvent resistance and gas barrier property were evaluated according to the following criteria.

[Making a coating film]
The water-based paint compositions prepared in Examples 1 to 35 and Comparative Examples 1 to 10 were applied to a 25 μm thick PET film treated with a corona discharge using a bar coater so that the film thickness after drying was 1.0 μm. Then, it was dried at 120 ° C. for 30 minutes to obtain a test piece of a coating film. Tables 2 and 3 show the evaluation results of the coated film.

[Making a self-supporting film]
The water-based paint compositions prepared in Examples 1 and 2 and Comparative Example 2 were applied to a PET film using a bar coater, dried at 120 ° C. for 30 minutes, and peeled off from the base PET film to obtain a self-supporting film. rice field. Table 4 shows the evaluation results of the self-supporting film.

[water resistant]
After immersing the coating film and the self-supporting film obtained in each Example and each Comparative Example in water at 25 ° C. for 10 days, the state of the coating film was visually judged according to the following criteria.
◯: The peeling or swelling of the coating film cannot be noticed.
Δ: Peeling or swelling of the coating film is observed in a part.
X: Peeling or swelling of the coating film is observed on the whole.

[Solude resistance]
Two filter papers are placed side by side on the coating films of the coating film and the self-supporting film obtained in each example and each comparative example, and 78% ethanol and toluene are dropped on each filter paper with a dropper to moisten the filter paper. rice field. The dropper was dropped 5 times at 1-hour intervals, and after 2 hours, the surface excluding the filter paper was visually evaluated according to the following criteria.
○: Abnormalities such as swelling and peeling are almost nonexistent and do not cause any problems △: Abnormalities such as slight swelling and peeling are found visually ×: The coating film melts

[Gas barrier property]
The oxygen permeability of the coated film and the self-supporting film obtained in each Example and each Comparative Example was measured under high humidity conditions. The oxygen permeability was measured using OX-TRAN2 / 21 manufactured by MOCON under the condition of 23 ° C.-85% RH.

As shown in Tables 2 and 3, the coating films obtained by using the water-based coating compositions of Examples 1 to 35 are excellent in each evaluation item. On the other hand, the coating films obtained by using the water-based coating compositions of Comparative Examples 1 to 10 are inferior to Examples 1 to 35 in each evaluation item. Further, as shown in Table 4, the self-supporting film obtained by using the water-based coating compositions of Examples 1 and 2 is superior to the self-supporting film of Comparative Example 2 in each evaluation item.

From the above, the coating film and the self-supporting film obtained by using the water-based coating composition containing a specific modified cellulose nanofiber, a polyvalent amine, and a water-based solvent are water-resistant and solvent-resistant under high humidity. , And excellent gas barrier properties under high humidity.

Claims (12)

An aqueous coating composition containing a modified cellulose nanofiber, a polyvalent amine, and an aqueous solvent, in which a part of the hydroxyl groups in the modified cellulose nanofiber is modified by an oxidation or substitution reaction and introduced by modification. The substituted substituent is the formula (1) :.
-COO ^- N ⁺ R ¹ R ² R ³ H (1)
(In the formula (1), R ¹ , R ² and R ³ are substituents constituting H or a monoamine having a boiling point of 110 ° C. or lower, respectively.)
The water-based coating composition further contains 0 to 100% by mass of a binder component with respect to the modified cellulose nanofibers.
The polyvalent amine has a molecular chain length of 4 or more consisting of C, O, and N between both terminal amino groups.
Water-based paint composition. In the water-based coating composition, the blending amount of the modified cellulose nanofibers is 0.5 to 30% by mass, and the amount of the substituents introduced by the modification of the modified cellulose nanofibers is larger than the amount of the substituents. The water-based coating composition according to claim 1, wherein the compounding ratio of the valent amine is 10 to 70% mol equivalent . The water-based coating composition according to claim 1 or 2, wherein the modified cellulose nanofibers contain oxidized cellulose nanofibers, and the amount of carboxyl groups of the oxidized cellulose nanofibers is 0.6 to 2.2 mmol / g. The modified cellulose nanofibers include carboxymethylated cellulose nanofibers, wherein the degree of carboxymethyl substitution per glucose unit of the carboxymethylated cellulose nanofibers is 0.01 to 0.50, according to claim 1 or 2. Water-based paint composition. The water-based paint composition according to any one of claims 1 to 4 , further comprising a preservative. The water-based paint composition according to any one of claims 1 to 5 , further comprising a rheology control agent. A one-component water-based paint composition using the water-based paint composition according to any one of claims 1 to 6 . A two-component water-based paint composition in which the modified cellulose nanofibers and the polyvalent amine are separated from the components contained in the water-based paint composition according to any one of claims 1 to 6 . A film containing the water-based coating composition according to any one of claims 1 to 8 . The mixing step of obtaining the water-based coating composition according to any one of claims 1 to 8 , and the mixing step.
A coating step of applying the water-based paint composition obtained in the mixing step to the support, and a coating step of applying the water-based paint composition to the support.
The support to which the water-based coating composition obtained in the coating step is applied is dried by heating to form a coating film derived from the water-based coating composition on the support. A process and a film manufacturing method that includes
A part of the hydroxyl group in the modified cellulose nanofiber is modified by an oxidation or substitution reaction, and the substituent introduced by the modification is the formula (1) :.
-COO ^- N ⁺ R ¹ R ² R ³ H (1)
(In the formula (1), R ¹ , R ² and R ³ are substituents constituting H or a monoamine having a boiling point of 110 ° C. or lower, respectively.) A method for producing a film. The method for producing a film according to claim 10 , wherein the support is a film-like base material, and the coating film is formed on the support in the coating film forming step to produce a coated film. The film manufacturing method according to claim 10 , further comprising a step of peeling the coating film formed on the support from the support, and manufacturing a self-supporting film composed of the coating film peeled from the support. ..