JP2021084960A - Cellulose derivative and cellulose derivative solution - Google Patents

Abstract

To provide a cellulose derivative which has excellent solubility in toluene and can impart sufficient thixotropic nature to the toluene, without the need to add alcohols.SOLUTION: The cellulose derivative has a degree of methyl group substitution from 0.01 to less than 2.0, and a degree of octyl group substitution from 1.0 to less than 3.0.SELECTED DRAWING: None

Description

The present invention relates to a cellulose derivative and a cellulose derivative solution.

Paint compositions such as oil-based paints and oil-based paints are mainly composed of coating components (for example, coating film-forming components such as fats and oils, synthetic resins, and natural resins; additives such as plasticizers, emulsifiers, and thickeners; And pigment); and a solvent and the like. As the solvent, hydrocarbons such as toluene are used.

Among them, the thickener can be added to the coating composition in order to adjust the workability when applied to the substrate. Examples of thickeners (thixotropic agents) include carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), methyl cellulose (MC), methyl hydroxylethyl cellulose (MHEC), and hydroxypropyl methyl cellulose (HPMC). ) And other cellulose derivatives are used. However, these cellulose derivatives have insufficient dispersibility and solubility in the coating composition. It is known that alcohols such as ethyl alcohol and isopropyl alcohol (IPA) are added to the coating composition together with the cellulose derivative in order to improve the dispersibility and solubility.

Special Table 2010-521554

However, when alcohols are added to the coating composition, the volatility of the solvent is increased, so that the formed coating film becomes uneven and the appearance of the coating film is deteriorated. In order to suppress poor appearance of the coating film, a cellulose derivative having excellent solubility in hydrocarbons such as toluene, which is a solvent of the coating composition, is used as a thickener (thixotropic agent) without adding alcohols. desirable.

An object of the present disclosure is to provide a cellulose derivative which is excellent in solubility in toluene and can impart sufficient thixotropy to toluene without adding alcohols.

The first aspect of the present disclosure relates to a cellulose derivative having a methyl group substitution degree of 0.01 or more and less than 2.0 and an octyl group substitution degree of 1.0 or more and less than 3.0.

In the cellulose derivative, the sum of the degree of methyl group substitution and the degree of octyl group substitution may be 2.0 or more.

The second aspect of the present disclosure is that the cellulose derivative and the solvent are contained, and the content of the cellulose derivative is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent. The present invention relates to a cellulose derivative solution containing one or more selected from the group consisting of hexane, toluene and xylene.

According to the cellulose derivative of the present disclosure, it is possible to provide a cellulose derivative which is excellent in solubility in toluene and can impart sufficient thixotropy to toluene without adding alcohols.

<Cellulose derivative>
The cellulose derivative of the present disclosure has a methyl group substitution degree of 0.01 or more and less than 2.0, and an octyl group substitution degree of 1.0 or more and less than 3.0.

Further, the cellulose derivative of the present disclosure is, in other words, a cellulose in which a part or all of hydrogen of a hydroxyl group is substituted with a methyl group and an octyl group.

The degree of methyl group substitution of the cellulose derivative is preferably 0.01 or more, preferably 0.2 or more, more preferably 0.5 or more, still more preferably 1.0 or more. Further, the degree of methyl group substitution of the cellulose derivative may be 1.8 or less, and may be 1.5 or less, where it is less than 2.0. If the degree of methyl group substitution of the cellulose derivative is too small, the solubility in hydrocarbons such as toluene is poor. If the degree of methyl group substitution is too large, it becomes difficult to introduce an octyl group during the production of a cellulose derivative.

The degree of octyl group substitution of the cellulose derivative may be 1.1 or more, and may be 1.2 or more, where it is 1.0 or more. Further, the degree of octyl group substitution may be less than 2.8, less than 2.5, and less than 2.0, where it is less than 3.0. If the degree of octyl group substitution of the cellulose derivative is too small, the solubility in a non-polar solvent containing hydrocarbons such as toluene, hexane, and xylene is poor. If the degree of octyl group substitution of the cellulose derivative is too large, the thixotropic property imparted to a non-polar solvent containing hydrocarbons becomes too low.

The sum of the degree of methyl group substitution and the degree of octyl group substitution of the cellulose derivative is preferably 1.5 or more, more preferably 2.0 or more, still more preferably 2.5 or more. The sum may be less than 3.0, less than 2.9, and less than 2.7.

The sum of the degree of substitution of each substituent of the cellulose derivative is referred to as the total degree of substitution, and the total degree of substitution of the cellulose derivative is preferably 1.5 or more, more preferably 2.0 or more, still more preferably 2.5 or more. Further, where the maximum value of the total substitution degree is 3.0, it may be less than 3.0, less than 2.9, or less than 2.7.

The degree of alkyl group substitution including the degree of methyl group substitution and the degree of octyl group substitution can be measured by the following method. It can be measured by a method according to ASTM: D-817-91, ¹³ C-NMR, and ^{1 H-NMR.}

Examples of conditions for quantifying the degree of methyl group substitution and the degree of octyl group substitution of the cellulose derivative by ¹ H-NMR are described below.

Equipment: JEOL JNM ECA-500
Temperature: 80 ° C
Solvent: DMSO
Sample concentration: 0.8 wt%
Calculation:
Methyl group substitution degree = 35β / (15α-15β-2γ)
Octyl group substitution degree = 7γ / (15α-15β-2γ)
α: Integral value of 5.40 to 2.70 ppm β: 3.51-3.41 Integral value of 3.32 to 3.25 ppm γ: Integral value of 1.65 to 0.70 ppm

The weight average molecular weight of the cellulose derivative (Mw) of, but are not limited to, preferably 1.0 × 10 ⁴ or more, 2.0 × more preferably 10 ⁴ or more, 3.0 × 10 ⁴ or more preferable. Further, the weight average molecular weight is preferably from 1.0 × 10 ⁶ or less, more preferably 5.0 × 10 ⁵ or less, more preferably 2.0 × 10 ⁵ or less. Within this range, the cellulose derivative is more excellent in solubility in hydrocarbons such as toluene.

The weight average molecular weight is a so-called weighted average value of molecular weight, which is obtained by multiplying the weight of each molecule by the molecular weight to obtain an average value, and can be measured by GPC.

By dissolving the cellulose derivative in a non-polar solvent containing hydrocarbons such as toluene, hexane, and xylene, excellent thixotropy can be imparted to those solvents.

The cellulose derivative can be produced, for example, as follows. Examples thereof include a production method including a step of converting a cellulose raw material into alkaline cellulose under basic conditions (activation step); and a step of reacting the alkali cellulose with an alkyl halide (etherification treatment).

More specifically, for example, a step of marcelifying a cellulose raw material with sodium hydroxide to obtain alkali cellulose; a step of reacting the alkali cellulose with a methylating agent to etherify it to obtain methyl cellulose; and then a base. Examples thereof include a production method (referred to as a two-step reaction) having a step of obtaining methyl octyl cellulose (cellulose derivative) by reacting the methyl cellulose with an octylizing agent to etherify it under sexual conditions. Further, methyloctyl cellulose (cellulose derivative) can also be obtained by reacting the alkaline cellulose with both a methylating agent and an octylizing agent to etherify it (referred to as a one-step reaction). The blending amount and blending ratio of the methylating agent and the octylling agent can be arbitrarily selected.

In order to accurately adjust the degree of substitution of the methyl group and the octyl group of methyl octyl cellulose (cellulose derivative), after obtaining methyl cellulose, the methyl cellulose is reacted with an octylizing agent to etherify the methyl octyl cellulose (cellulose). A method (two-step reaction) having a step of obtaining the derivative) is preferable.

Examples of the methylating agent include methyl halides such as methyl chloride, and examples of the octylizing agent include octyl halides such as octyl chloride.

<Cellulose derivative solution>
The cellulose derivative solution of the present disclosure contains the cellulose derivative and the solvent, and the content of the cellulose derivative is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent.

The cellulose derivative solution is a solution in which the cellulose derivative is dissolved in a solvent, and it is visually observed whether or not the solution is a solution in which the cellulose derivative is dissolved. When the shape of a solid substance, a swollen body, a gel-like body, or the like of a cellulose derivative is observed, it cannot be said to be a solution. If these shapes cannot be confirmed and are transparent, it is a solution.

Examples of the solvent for the cellulose derivative solution include non-polar solvents containing hydrocarbons such as toluene, hexane, and xylene; and polar solvents such as methyl ethyl ketone and ketone-based organic solvents such as methyl isobutyl ketone. Of these, a solvent containing one or more selected from the group consisting of hexane, toluene and xylene is preferable. This is because the coating film property and volatility are improved and the workability is improved.

The content of the cellulose derivative in the cellulose derivative solution is 0.1 parts by mass or more and 20 parts by mass or less, preferably 0.1 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the solvent. More preferably, it is 5 parts by mass or more.

The thixotropy index value of the cellulose derivative solution of the present disclosure is preferably 5 or more, and more preferably 10 or more. Moreover, it may be 50 or less.

The thixotropy index value is an index of thixotropy in which the viscosity decreases as the applied force increases. The larger the value, the higher the thixotropy.

The thixotropy index value can be measured by the following method. First, 5 parts by mass of a sample is dissolved in 95 parts by mass of NMP to prepare an NMP solution, and the viscosity at a rotation speed of 0.5 rpm under the following devices and conditions (1) to (4). , And the viscosity at a rotation speed of 50 rpm.
(1) Equipment: TV-22 (manufactured by Toki Sangyo Co., Ltd.)
(2) Measuring jig: Cone plate (1 ° 34'x R24),
(3) Temperature: 25 ° C
(4) Rotation speed: 0.5 rpm, 50 rpm

Next, the viscosity at a rotation speed of 0.5 rpm / the viscosity at a rotation speed of 50 rpm is calculated as a thixotropy index value (TI value).

[Use]
The cellulose derivatives of the present disclosure have solubility in non-polar solvents containing hydrocarbons such as toluene, hexane, and xylene without the addition of alcohols. Therefore, by adding it to the coating composition, it is possible to form a coating film that functions as a thickener (thixotropic agent) of the coating composition and suppresses the appearance deterioration of the coating film.

The cellulose derivative solution of the present disclosure is used as a coating film-forming component such as fats and oils, synthetic resins, and natural resins; additives such as plasticizers, emulsifiers, and other thickeners; and conventionally known coatings such as pigments. A coating composition can be prepared by mixing with the membrane components.

Hereinafter, the present disclosure will be described in detail based on examples, but the technical scope is not limited by these examples.

Various measurements in Examples and Comparative Examples were carried out by the following methods.
<Degree of substitution>
The degree of alkyl group substitution (degree of methyl group substitution and degree of octyl group substitution) was ^{quantified by 1} H-NMR under the following conditions.
Equipment: JEOL JNM ECA-500
Temperature: 80 ° C
Solvent: DMSO
Sample concentration: 0.8 wt%
Calculation:
Methyl group substitution degree = 35β / (15α-15β-2γ)
Octyl group substitution degree = 7γ / (15α-15β-2γ)
α: Integral value of 5.40 to 2.70 ppm β: 3.51-3.41 Integral value of 3.32 to 3.25 ppm γ: Integral value of 1.65 to 0.70 ppm

<Evaluation of solvent solubility>
200 g of the predetermined solvent was collected in a 300 ml beaker, and 2 g of the sample was added to the place where the mixture was stirred at room temperature (25 ° C.) or 80 ° C. with a magnetic stirrer. The subsequent state was visually observed and the solubility in each solvent was evaluated according to the following criteria. As the solvent, hexane, toluene and xylene were used as non-polar solvents.
⊚: Easy complete dissolution at room temperature 〇: Completely dissolved by heating to 80 ° C Δ: Swelling or gelation even when heated to 80 ° C ×: Insoluble even when heated to 80 ° C

<Evaluation of thixotropy>
First, at 60 ° C., 5 parts by mass of a sample was dissolved in 95 parts by mass of NMP to prepare an NMP solution, and the rotation speed was 0.5 rpm under the following devices and conditions (1) to (4). And the viscosity at a rotation speed of 50 rpm were determined.
(1) Equipment: TV-22 (manufactured by Toki Sangyo Co., Ltd.)
(2) Measuring jig: Cone plate (1 ° 34'x R24),
(3) Temperature: 25 ° C
(4) Rotation speed: 0.5 rpm, 50 rpm

Next, the viscosity at a rotation speed of 0.5 rpm / the viscosity at a rotation speed of 50 rpm was calculated as a thixotropy index value (TI value), and the thixotropy property was evaluated according to the following criteria.
⊚: TI value is 10 or more ○: TI value is 5 or more and less than 10 ×: TI value is less than 5

<Synthesis of methyl cellulose>
(MC-1)
100 g of crushed pulp and an aqueous sodium hydroxide solution (75 g of sodium hydroxide (NaOH), 150 ml of water) were added to a 2 L autoclave with a stirrer, and the mixture was stirred at 45 ° C. for 1 hour under a nitrogen atmosphere (first step). After allowing to cool, the mixture is cooled to −40 ° C. in a dry ice / methanol bath, and further, 150 ml of toluene, 120 g of chloromethane, 60 ° C. (reaction temperature (1)) for 1 hour (reaction time (1)), and then 100 ° C. (reaction). Stirring at temperature (2)) for 3 hours (reaction time (2)) (second step). After returning to room temperature, the residual gas in the system was exhausted and poured into 12 L of methanol with vigorous stirring to obtain a white solid (third step). The white solid was filtered off by suction filtration and washed 3 times with a large amount of isopropyl alcohol. The obtained white solid was vacuum dried at 100 ° C. for 6 hours to obtain methyl cellulose (MC-1) as a white powder (yield 98 g). The degree of methyl group substitution of methyl cellulose (MC-1) is shown in Table 1.

(MC-2 to 5)
Each methyl cellulose (MC-2, MC-3, MC-4 and MC-5) was prepared in the same manner as in the synthesis of MC-1 except that the conditions in the first step and the second step were changed as shown in Table 1. Obtained. The degree of methyl group substitution of each methyl cellulose is shown in Table 1.

(MC-6)
Methyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as MC-6.

<Synthesis of methyloctyl cellulose>
(Example 1)
To a 2 L autoclave with a stirrer, 100 g of methyl cellulose (MC-2) and 520 g of a 48% sodium hydroxide aqueous solution were added as raw materials. After stirring at room temperature for 1 hour, 500 mL of toluene and 1920 g of octyl chloride were added, and the mixture was stirred at room temperature for 30 minutes. Further, the mixture was stirred at 130 ° C. (reaction temperature) for 11 hours (reaction time), and after the reaction was completed, the temperature was returned to room temperature. The white solid was filtered by suction filtration and then washed 3 times with a large amount of isopropyl alcohol. The obtained white solid was vacuum dried at 100 ° C. for 6 hours to obtain methyloctyl cellulose as a white powder (yield 105 g).

Table 3 shows the results of evaluating each physical property of the obtained methyloctyl cellulose.

(Examples 2 to 7, Comparative Examples 7 to 13)
Each methyloctyl cellulose was obtained in the same manner as in Example 1 except that the raw material, the amount of octyl chloride, the amount of 48% aqueous sodium hydroxide solution, and the reaction temperature and reaction time were changed as shown in Table 2. Table 3 shows the results of evaluating each physical property of the obtained methyloctyl cellulose.

(Comparative Examples 1 to 6)
The results of evaluating the physical characteristics of each of the methyl celluloses (MC-1, MC-2, MC-3, MC-4, MC-5 and MC-6) shown in Table 2 are shown in Table 3.

As shown in Table 3, the cellulose derivatives of Examples have excellent solubility in non-polar solvents containing hydrocarbons such as toluene, hexane, and xylene without the addition of alcohols, and toluene. It can be seen that sufficient thixotropy can be imparted to the substance. Therefore, the cellulose derivative of the example is suitable as a thickener (thixotropic agent) that can be contained in the coating composition. Further, according to the cellulose derivative of the example, it is possible to suppress the appearance deterioration of the coating film.

Claims (3)

The degree of methyl group substitution is 0.01 or more and less than 2.0,
A cellulose derivative having an octyl group substitution degree of 1.0 or more and less than 3.0. The cellulose derivative according to claim 1, wherein the sum of the degree of methyl group substitution and the degree of octyl group substitution is 2.0 or more. Contains the cellulose derivative and solvent according to claim 1 or 2.
The content of the cellulose derivative is 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent.
A cellulose derivative solution containing one or more selected from the group consisting of hexane, toluene and xylene as the solvent.