JP7012516B2 - Saponification accelerator for diacetate fiber or triacetate fiber - Google Patents

Description

The present invention relates to a diacetate fiber or a saponification accelerator for a triacetate fiber, a method for producing an acetate fiber using the saponification accelerator, and a method for saponifying a diacetate fiber or a triacetate fiber.

Conventionally, acetate fibers have been saponified by hydrolyzing the acetylated portion of the fibers to form them into cellulose (deacetylation). In such a saponification process, the acetate fiber is saponified to modify the fiber itself and perform various special processes.

Examples of the modification of the acetate fiber include improvement of water absorption and impartation of crimping. In addition, as a special process, an alkaline compound is attached by printing or pad method and heat-treated to make parts with different degrees of vinegarization on the fibers, and the parts with low degree of vinegarization are decomposed with sulfuric acid or the like for transparency. Examples include processing to obtain a pattern and dyeing with a different color using the property that the part with a high degree of vinegar is easily dyed with a dye for acetate and the part with a low degree of vinegar is easily dyed with a dye for cellulose.

Among acetate fibers, diacetate fibers have relatively high hydrophilicity and can be easily saponified by alkaline treatment, but it is difficult to control the degree of saponification (degree of vinegarization). Further, the triacetate fiber has higher hydrophobicity than the diacetate fiber and can be saponified by alkaline treatment, but it is more difficult to control the degree of saponification (degree of vinegarization).

For example, Patent Documents 1 to 3 disclose methods for dipping a cloth such as diacetate fiber, triacetate fiber, and cellulose fatty acid ester fiber with a treatment agent containing an alkaline compound and a quaternary ammonium salt. However, cationic surfactants such as quaternary ammonium salts tend to remain in the dough. If the quaternary ammonium salt remains on the dough, it causes harmful effects such as irritation to the skin and sensitization. Therefore, it is necessary to anionize the fabric after the saponification treatment using an anionic surfactant. Further, since the quaternary ammonium salt is highly environmentally toxic, it is necessary to perform an anionization treatment on the treatment liquid as in the case of the cloth.

Further, for example, in Patent Document 4, guanidine hydrochloride and an alkali metal salt of a weak acid are used without using a strong alkaline compound (sodium hydroxide, potassium hydroxide, etc.) as a saponifying agent, or a weak acid salt of guanidine is used. The method for performing saponification is disclosed. However, in the method of Patent Document 4, when saponification is performed by the printing or pad method, the degree of saponification is affected by the amount of the saponifying agent applied, the amount adhered by the pickup, and the heat treatment method. There is a problem that saponification cannot be performed so that the degree of vinegarization is arbitrary. Further, in the method of Patent Document 4, it is necessary to perform heat treatment after printing or pad processing, and saponification cannot be performed at one time, so that a large amount of process energy is required.

Japanese Unexamined Patent Publication No. 54-151698 Japanese Unexamined Patent Publication No. 7-82668 Japanese Unexamined Patent Publication No. 2004-115933 Japanese Unexamined Patent Publication No. 2008-308771

An object of the present invention is to provide a saponification accelerator capable of suitably promoting a saponification reaction with a saponifying agent and saponifying a diacetate fiber or a triacetate fiber to a desired degree of vinegarization. It is also an object of the present invention to provide a method for producing an acetate fiber using the saponification accelerator, and a method for saponifying a diacetate fiber or a triacetate fiber.

The present inventors have made diligent studies to solve the above problems. As a result, it was found that by using a guanidine compound as a saponification accelerator, the saponification reaction of the saponifying agent can be suitably promoted and the diacetate fiber or the triacetate fiber can be saponified to a desired degree of vinegarization. The present invention has been completed by further studies based on these findings.

That is, the present invention provides the inventions of the following aspects.
Item 1. A saponification accelerator for diacetate fibers or triacetate fibers, including guanidine compounds.
Item 2. Item 2. The saponification accelerator according to Item 1, wherein the guanidine compound is a guanidine salt.
Item 3. Item 2. The saponification accelerator according to Item 1 or 2, which is used together with a saponification agent containing an alkaline compound.
Item 4. Item 2. The saponification accelerator according to any one of Items 1 to 3, wherein the diacetate fiber and the triacetate fiber are in the form of a composite fiber with another fiber.
Item 5. A method for producing an acetate fiber, comprising a saponification step of saponifying at least a part of a diacetate fiber or a triacetate fiber by using a saponifying agent and the saponification accelerator according to any one of Items 1 to 4.
Item 6. Item 5. The method for producing an acetate fiber according to Item 5, wherein in the saponification step, the diacetate fiber or the triacetate fiber is immersed in a solution containing the saponification agent and the saponification accelerator.
Item 7. Item 5. The method for producing an acetate fiber according to Item 5 or 6, wherein in the saponification step, the degree of vinegarization of the diacetate fiber or the triacetate fiber is adjusted by adjusting the amounts of the saponification agent and the saponification accelerator used.
Item 8. Item 6. The method for producing an acetate fiber according to any one of Items 5 to 7, wherein the diacetate fiber and the triacetate fiber are cloths.
Item 9. Item 5. The item 5 to 8, wherein the diacetate fiber and the triacetate fiber are in the form of a composite fiber with another fiber, and the produced acetate fiber is a composite fiber with another fiber. The method for producing an acetate fiber according to the above method.
Item 10. Saponification of diacetate fiber or triacetate fiber comprising a saponification step of saponifying at least a part of diacetate fiber or triacetate fiber using a saponification agent and the saponification accelerator according to any one of Items 1 to 4. Method.

According to the present invention, it is possible to provide a saponification accelerator capable of preferably promoting a saponification reaction with a saponifying agent and saponifying a diacetate fiber or a triacetate fiber to a desired degree of vinegarization. Further, according to the present invention, it is also possible to provide a method for producing an acetate fiber using the saponification accelerator, and a method for saponifying a diacetate fiber or a triacetate fiber.

1. 1. Saponification Accelerator The saponification accelerator of the present invention is characterized by containing a guanidine-based compound. The saponification accelerator of the present invention can suitably promote the saponification reaction of diacetate or triacetate by the saponifying agent, and saponify the diacetate fiber or triacetate fiber to a desired degree of vinegarization (substitution degree).

As will be described later, acetate (cellulose acetate) is a semi-synthetic polymer obtained by esterifying cellulose, which is a natural polymer, with acetic acid esterification. Cellulose is a polymer having anhydrous glucose as a repeating unit, has three hydroxyl groups per repeating unit, and acetate fibers having different properties can be obtained depending on the degree of esterification of the hydroxyl groups (degree of substitution).

The degree of substitution of acetate fibers is generally expressed as an index called the degree of vinegarization. Acetate fibers widely used industrially are roughly classified into two types, diacetate (cellulose diacetate) fiber and triacetate (cellulose triacetate) fiber, and the degree of vinegarization of each is about 55% (average degree of substitution 2). .4), about 61% (average degree of substitution 2.9). By saponifying the diacetate fiber or triacetate fiber and adjusting the degree of vinegarization to a desired degree, the fiber itself is modified and various special treatments are performed as described above.

Due to the difference in molecular weight between the acetate group and the hydroxyl group of the acetate fiber, even if the acetate fiber is saponified according to theory, the degree of substitution and the degree of vinegarization do not have a linear relationship. You can check it. In the present invention, the degree of vinegarization of the acetate fiber is a value measured by the following method.

<Measurement of vinegarization degree of acetate fiber>
1 g of the sample (acetate fiber) is precisely weighed in an Erlenmeyer flask, and the sample is dissolved in 70 mL of acetone and 15 mL of dimethyl sulfoxide. Add 15 mL of 1 mol / L sodium hydroxide and stir for 2 hours. Add warm water at about 50 ° C., stir for 15 minutes, add a few drops of phenolphthalein solution, and titrate with 0.5 mol / L sulfuric acid until colorless. The degree of vinegarization (%) is calculated by the following formula.
Degree of vinegarization (%) = (blank test sulfate titration (mL) -sulfuric acid titration (mL) x sulfuric acid titer x 6.005 / sample weight (g)

In the guanidine-based compound of the present invention, the guanidine compound is not particularly limited as long as it has an action of promoting the saponification reaction by the saponifying agent, but diacetate fibers or triacetate fibers are sacinated to a desired degree of vinegarization. From the viewpoint, guanidine salts such as guanidine phosphate, guanidine carbonate, guanidine sulfamate, guanidine hydrochloride, guanidine sulfate, guanidine nitrate, guanidine thiocyanate, aminoguanidine bicarbonate, and guanidine methylol phosphate are preferred. As the guanidine compound, only one kind may be used, or two or more kinds may be mixed and used.

The saponification accelerator of the present invention may contain a component different from the guanidine-based compound as the saponification accelerator. Examples of such different components include components blended in conventionally known saponification accelerators. However, from the viewpoint of environmental toxicity, as described later, when a mixed fiber of acetate fiber and other fiber (including polyester fiber, for example) is used, the amount of other fiber is also reduced. Therefore, the saponification accelerator of the present invention is used. Is preferably free of quaternary ammonium salts.

The saponification agent used together with the saponification accelerator of the present invention is not particularly limited as long as it is used for saponification of diacetate fiber or triacetate fiber, but an alkaline compound is preferable, and sodium hydroxide is more preferable. , Strong alkaline compounds such as potassium hydroxide, and more preferably sodium hydroxide. As the saponifying agent, only one kind may be used, or two or more kinds may be mixed and used.

Acetate fiber is a semi-synthetic polymer fiber obtained by esterifying cellulose with acetic acid. Acetate fibers are roughly classified into diacetate fibers and triacetate fibers according to the degree of substitution that is esterified, and the degree of vinegarization of the diacetate fibers is about 55% (the degree of substitution is 2.22 or more and less than 2.76 (average substitution). The degree is 2.4)), and the degree of vinegarization of the triacetate fiber is about 61% (the degree of substitution is 2.76 or more and less than 3.00 (the average degree of substitution is 2.9)).

The repeating unit of the molecule constituting the acetate fiber can be expressed by the following formula. In the following formula, the substituent R is an acetic acid group or a hydroxyl group.

The saponification accelerator of the present invention can be a target for saponification of both diacetate fibers and triacetate fibers. As described above, in the acetate fiber, the diacetate fiber has a relatively high hydrophilicity and can be easily saponified by alkaline treatment, but it is difficult to control the degree of saponification (degree of vinegarization). Further, the triacetate fiber has higher hydrophobicity than the diacetate fiber and can be saponified by alkaline treatment, but it is more difficult to control the degree of saponification (degree of vinegarization). On the other hand, by using the saponification accelerator of the present invention, not only the diacetate fiber but also the triacetate fiber can be saponified by alkaline treatment while controlling the saponification degree (saponification degree). Therefore, it can be said that the saponification accelerator of the present invention has a very high utility value as a saponification accelerator for triacetate fibers.

When the acetate fiber is saponified, the acetic acid group is replaced with a hydroxyl group. When the acetic acid group is replaced with a hydroxyl group, the molecular weight of the acetate fiber is reduced and the weight is reduced. Therefore, the degree of substitution of the acetic acid group can be confirmed by the weight loss rate of the acetate fiber. For example, the average degree of substitution of triacetate is 2.9, and if all acetic acid groups are saponified, the weight loss will be about 42.92%. The method for measuring the weight loss rate of the acetate fiber is as follows.

<Weight loss rate of acetate fiber>
The weight of the acetate fiber before and after the saponification step is measured, and the weight loss rate of the acetate fiber is calculated by the following formula based on the weight change.
Weight loss rate of acetate fiber = (weight of acetate fiber before saponification step-weight of acetate fiber after saponification step) / (weight of acetate fiber before saponification step) x 100

Taking triacetate (average degree of substitution 2.9) as an example, when an acetic acid group is saponified to a hydroxyl group according to theory by sodium hydroxide as a saponifying agent, the degree of substitution of acetate, the saponification rate, and 1 of acetate. Table 1 below shows the theoretical relationship between the molecular weight of the unit, the degree of saponification, and the weight loss rate.

Further, since sodium hydroxide as a saponifying agent has a molecular weight of 40, for example, in the case of saponifying triacetate with sodium hydroxide, the theoretical amount of sodium hydroxide used (% (o.w.f)). Is calculated by the following formula. Table 2 below shows the theoretical relationship between the amount of sodium hydroxide used, the degree of substitution of acetate, the desired saponification rate X (%), the molecular weight of one unit of acetate, the degree of vinegarization, and the weight loss rate. ..

Amount of sodium hydroxide used (% (o.w.f.)) = weight of triacetate fiber / 567.60 (molecular weight of 1 unit of triacetate) x 5.8 (average number of acetic acid groups in 1 unit of triacetate) x 40 (Molecular weight of sodium hydroxide) x X (desired saponification rate%) / 100 / weight of triacetate fiber x 100

That is, in the present invention, the amount of the saponifying agent used is adjusted by the degree of substitution of the acetate fiber (that is, diacetate or triacetate) to be saponified and the desired degree of saponification after saponification, for example, Table 2. As shown in the above, when saponifying triacetate (average value sensitivity 2.9) with sodium hydroxide, the adjustment is made in the range of 10.22 to 40.87% (owf).

Further, in the present invention, the amount of the saponification accelerator used can be adjusted together with the amount of the saponification agent used, and is not particularly limited, but is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the acetate fiber. , More preferably 1 to 30 parts by mass, still more preferably 5 to 15 parts by mass.

When an alkaline compound is used as the saponification agent, there is a method of measuring the pH of the bath solution after the saponification step as a method of confirming that the saponification agent is consumed after saponification. For example, the amount of sodium hydroxide required to saponify an acetic acid group in half by saponification of triacetate is theoretically 20% (o.w.f.) = 10 g based on the weight of triacetate. Since / L (when the bath ratio is 1:20) = 0.25 mol / L, the pH is 13.4. Since the saponification of triacetate consumes the saponifying agent and lowers the pH of the bath solution, the amount of the saponifying agent in the bath solution can be measured by measuring the pH of the bath solution. As shown in Table 3 below, for example, when the saponifying agent is sodium hydroxide, when the pH of the bath solution is 11 or less, the amount of sodium hydroxide in the bath solution is 0.001 mol / L or less, which is 98%. The above sodium hydroxide is consumed.

In the present invention, the morphology of the diacetate fiber and the triacetate fiber is not particularly limited, but is generally a cloth.

The diacetate fiber and the triacetate fiber to be sacrificed by the saponification accelerator of the present invention may be in the form of a composite fiber with another fiber (that is, a fiber different from the acetate fiber), or the composite fiber may be used. May be a cloth. As described above, the saponification accelerator of the present invention can suitably promote the saponification reaction by the saponifying agent and saponify the diacetate fiber or the triacetate fiber to a desired degree of vinegarization, while, for example, the polyester fiber by the saponifying agent. There is no weight loss promotion effect. Therefore, the saponification accelerator of the present invention can also be suitably used as a saponification accelerator for a composite fiber of at least one of a diacetate fiber and a triacetate fiber and another fiber such as a polyester fiber.

The other fibers are not particularly limited as long as they are different from acetate fibers, and are not particularly limited, and are polyester fibers, polyamide fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polyacrylonitrile fibers, polyolefin fibers, and polyethers. Examples thereof include various synthetic resin fibers such as ester fibers and polyurethane fibers. Further, the other fiber may be an inorganic fiber such as a metal fiber, a carbon fiber or a glass fiber, or may be a natural polymer fiber such as a cellulose fiber. As the other fiber, only one kind may be used, or two or more kinds may be mixed and used.

Among other fibers, the composite fiber preferably contains a polyester fiber. That is, it is preferable that the composite fiber of at least one of the diacetate fiber and the triacetate fiber and the other fiber contains at least one of the diacetate fiber and the triacetate fiber and the polyester fiber.

The polyester fiber is a fiber composed of a polyester resin, and examples of the polyester resin include polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, and polybutylene terephthalate.

In the composite fiber of at least one of the diacetate fiber and the triacetate fiber and the other fiber, these ratios (total mass of the diacetate fiber and the triacetate fiber: the mass of the other fiber) are not particularly limited, and are not particularly limited, for example. About 100: 1 to 100: 10000 can be mentioned.

2. 2. Method for Producing Acetate Fiber The method for producing acetate fiber of the present invention comprises a saponification step of saponifying at least a part of diacetate fiber or triacetate fiber using a saponifying agent and a saponification accelerator of the present invention. For details on the types, amounts, forms and the like of the saponification accelerator, saponification agent, diacetate fiber and triacetate fiber of the present invention, refer to [1. As explained in the item of [Saponification accelerator]. In addition, the degree of substitution, saponification rate (%), saponification degree (%), weight loss rate (%), acetate 1 unit molecular weight, and sodium hydroxide when the acetate fiber is theoretically saponified by the saponifying agent are added. Regarding the theoretical relationship with the amount used (% (o.w.f)) when used as a saponifying agent, [1. As explained in the item of [Saponification accelerator].

According to the method for producing an acetate fiber of the present invention, the saponification reaction by a saponifying agent can be suitably promoted, and the diacetate fiber or the triacetate fiber can be saponified to a desired degree of vinegarization (substitution degree). Furthermore, since it is not necessary to use an excessive amount of the saponifying agent, it is possible to reduce the amount of the saponifying agent that was not used in the saponification step.

In the saponification step of the method for producing an acetate fiber of the present invention, the method of the saponification step using a saponification agent and a saponification accelerator is not particularly limited as long as the saponification agent and the saponification accelerator can be brought into contact with the diacetate fiber or the triacetate fiber. , A treatment (immersion treatment) in which the diacetate fiber or the triacetate fiber is immersed in a solution containing a saponification agent and a saponification accelerator is preferable.

In the dipping treatment, the solution containing the saponification agent and the saponification accelerator is preferably an aqueous solution. Further, in the dipping treatment, the bath ratio (mass of fiber to be treated: mass of solution) is not particularly limited, but is preferably about 1: 1 to 1: 100.

As described above, the amounts of the saponification agent and the saponification accelerator used in the saponification step are adjusted according to the degree of vinegarization of the target diacetate fiber or triacetate fiber, respectively. It is sufficient that the diacetate fiber or the triacetate fiber is saponified according to the theory by the saponifying agent, but when only the saponifying agent is used, it is not possible to control the saponification degree (the degree of vinegarization) so that the saponification degree becomes the theoretical degree. difficult. In particular, triacetate fibers are more hydrophobic than diacetate fibers and can be saponified by alkaline treatment, but it is particularly difficult to control the degree of saponification (degree of vinegarization). On the other hand, in the method for producing acetate fiber of the present invention, since the saponification agent and the saponification accelerator of the present invention are used in the saponification step, diacetate is adjusted by adjusting the amount of the saponification agent and the saponification accelerator. The fiber or triacetate fiber can be suitably saponified to the desired degree of vinegarization.

As described above, in the method for producing an acetate fiber of the present invention, the diacetate fiber and the triacetate fiber to be saponified may each be in the form of a composite fiber with another fiber, and the composite fiber is a cloth. There may be.

In the method for producing an acetate fiber of the present invention, the temperature in the saponification step is not particularly limited, but is preferably about 40 to 130 ° C, more preferably about 60 to 110 ° C. The saponification step may be carried out by raising the temperature from a low temperature (about 20 to 50 ° C.) to a high temperature (temperature in the saponification step), or after reaching a high temperature (temperature in the saponification step) from a low temperature. It may be held for a predetermined time. The rate of temperature rise is not particularly limited, and examples thereof include about 1 to 15 ° C./min. The time of the saponification step is not particularly limited, but is preferably about 1 to 120 minutes, and more preferably about 10 to 60 minutes.

In the method for producing acetate fiber of the present invention, the pH of the bath solution after the saponification step is preferably 11 or less. As described above, for example, when the saponifying agent is sodium hydroxide, when the pH of the bath solution is 11 or less, the amount of sodium hydroxide in the bath solution is 0.001 mol / L or less, and the hydroxide is 98% or more. Sodium is being consumed.

In the method for producing an acetate fiber of the present invention, after the saponification step, if desired, steps such as washing with water, dehydration, and drying may be performed.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

In the following Examples and Comparative Examples, the weight loss rate of the acetate fiber, the degree of vinegarization of the acetate fiber, and the pH of the bath solution after the saponification step were measured by the following methods, respectively.

<Weight loss rate of acetate fiber>
The weight of the acetate fiber before and after the saponification step was measured, and the weight loss rate of the acetate fiber was calculated by the following formula based on the change in weight. As described above, when the acetate fiber is saponified, the acetic acid group is replaced with a hydroxyl group and the weight is reduced, so that the change in the degree of substitution can be confirmed by the weight loss rate. For example, the average degree of substitution of triacetate is 2.9, and if all acetic acid groups are saponified, the weight loss will be about 42.92%.
Weight loss rate of acetate fiber = (weight of acetate fiber before saponification step-weight of acetate fiber after saponification step) / (weight of acetate fiber before saponification step) x 100

<Degree of vinegarization of acetate fiber>
1 g of the sample (acetate fiber) is precisely weighed in an Erlenmeyer flask, and the sample is dissolved in 70 mL of acetone and 15 mL of dimethyl sulfoxide. Add 15 mL of 1 mol / L sodium hydroxide and stir for 2 hours. Add warm water at about 50 ° C., stir for 15 minutes, add a few drops of phenolphthalein solution, and titrate with 0.5 mol / L sulfuric acid until colorless. The degree of vinegarization (%) is calculated by the following formula. The theoretical relationship between the degree of substitution of the acetate fiber, the saponification rate, the molecular weight of one unit of acetate, the degree of vinegarization, and the weight loss rate is as shown in Table 1 above.
Degree of vinegarization (%) = (blank test sulfate titration (mL) -sulfuric acid titration (mL) x sulfuric acid titer x 6.005 / sample weight (g)

<Measurement of pH of bath liquid after saponification process>
The pH of the bath solution after the saponification step was measured using a pH meter (D-51 manufactured by HORIBA, Ltd.). As described above, for example, the amount of sodium hydroxide required to saponify an acetic acid group by half by saponification of triacetate is theoretically 20% (o.w.f.) based on the weight of triacetate. Since) = 10 g / L (when the bath ratio is 1:20) = 0.25 mol / L, the pH is 13.4. Since the saponification of triacetate consumes the saponifying agent and lowers the pH of the bath solution, the amount of the saponifying agent in the bath solution can be measured by measuring the pH of the bath solution. As shown in Table 3 above, when the pH is 11 or less, the sodium hydroxide becomes 0.001 mol / L or less, and it can be seen that 98% or more of the sodium hydroxide is consumed.

<Example 1>
For triacetate long fiber tricot knitted fabric (manufactured by Mitsubishi Chemical), 10% sodium hydroxide as a saponifying agent for the purpose of performing a saponification step with a weight loss rate of about 10% and a saponification degree of about 50% after the saponification step. (Owf.), Using 5 g / L of a 60% aqueous solution of guanidine phosphate as a saponification accelerator, a bath so as to have a bath ratio of 1:20 (mass of triacetate long fiber tricot knitted fabric: mass of bath liquid). The liquid was prepared. Next, the bath temperature was raised from 40 ° C. to 3 ° C./min with a mini-color dyeing tester, and a saponification step (saponification treatment) was performed for 30 minutes after reaching 100 ° C. After the saponification step, the mixture was cooled to 80 ° C., the acetate fiber cloth was taken out, washed with water, dehydrated and dried to obtain an acetate fiber cloth.

<Example 2>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Example 1 except that 10 g / L of a 30% aqueous solution of guanidine carbonate was used as the saponification accelerator instead of the saponification accelerator of Example 1.

<Example 3>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Example 1 except that 5 g / L of a 60% aqueous solution of guanidine sulfamate was used as the saponification accelerator instead of the saponification accelerator of Example 1.

<Example 4>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Example 1 except that 5 g / L of a 60% aqueous solution of guanidine hydrochloride was used as the saponification accelerator instead of the saponification accelerator of Example 1.

<Comparative Example 1>
The saponification step was carried out in the same manner as in Example 1 except that the saponification accelerator was not used, to obtain an acetate fiber cloth.

Table 4 shows the weight loss rate of acetate fibers, the degree of vinegarization of acetate fibers, and the pH of the bath solution after the saponification step for Examples 1 to 4 and Comparative Example 1.

As is clear from the results shown in Table 4, in Examples 1 to 4 in which the guanidine-based compound was used as the saponification accelerator, the triacetate fiber cloth was saponified at a low temperature of 100 ° C., and the acetate after the saponification step was performed as intended. The saponification step could be performed with a weight loss rate of about 10% and a vinegarization degree of about 50%. That is, in Examples 1 to 4, sodium hydroxide as a saponifying agent was consumed almost according to the theoretical value by the saponification step, and an acetate fiber cloth having a desired weight loss rate and vinegarization degree was obtained. Further, from the pH of the bath solution after the saponification step, it can be seen that in Examples 1 to 4, 99% or more of sodium hydroxide is consumed. On the other hand, in Comparative Example 1 in which the saponification accelerator was not used, the degree of vinegarization was about 55%, and the weight loss rate of the acetate fiber fabric after the saponification step was 5.3%. Further, in Comparative Example 1, the pH of the bath solution after the saponification step was 12.4, and it can be seen that the desired saponification did not sufficiently proceed.

<Example 5>
For triacetate long fiber tricot knitted fabric (manufactured by Mitsubishi Chemical), use sodium hydroxide as a saponifying agent for the purpose of performing a saponification step with a weight loss rate of about 20% and a saponification degree of about 40% after the saponification step. An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Example 1 except that the amount was changed to 20% (owf.).

<Example 6>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Example 5 except that 10 g / L of a 30% aqueous solution of guanidine carbonate was used as the saponification accelerator instead of the saponification accelerator of Example 1.

<Example 7>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Example 5 except that 5 g / L of a 60% aqueous solution of guanidine sulfamate was used as the saponification accelerator instead of the saponification accelerator of Example 1.

<Example 8>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Example 5 except that 5 g / L of a 60% aqueous solution of guanidine hydrochloride was used as the saponification accelerator instead of the saponification accelerator of Example 1.

<Comparative Example 2>
The saponification step was carried out in the same manner as in Example 5 except that the saponification accelerator was not used, to obtain an acetate fiber cloth.

Table 5 shows the weight loss rate of acetate fibers, the degree of vinegarization of acetate fibers, and the pH of the bath solution after the saponification step for Examples 5 to 8 and Comparative Example 2.

As is clear from the results shown in Table 5, in Examples 5 to 8 in which the guanidine-based compound was used as the saponification accelerator, the triacetate fiber cloth was saponified at a low temperature of 100 ° C., and after the saponification step as intended. The saponification step could be performed with a weight loss rate of about 20% and a vinegarization degree of about 40% for the acetate fiber cloth. That is, in Examples 5 to 8, sodium hydroxide as a saponifying agent was consumed almost according to the theoretical value by the saponification step, and an acetate fiber cloth having a desired weight loss rate and vinegarization degree was obtained. Further, from the pH of the bath solution after the saponification step, it can be seen that in Examples 5 to 8, 99% or more of sodium hydroxide is consumed. On the other hand, in Comparative Example 2 in which the saponification accelerator was not used, the degree of vinegarization was about 50%, and the weight loss rate of the acetate fiber fabric after the saponification step was 13.3%. Further, in Comparative Example 2, the pH of the bath solution after the saponification step is 13.0, and it can be seen that the predetermined saponification has not sufficiently proceeded.

<Example 9>
Regarding the bath liquid used in the saponification step of Example 5, in order to confirm the weight loss effect on polyester fibers, polyester double picket (manufactured by Color Dyeing Co., Ltd.) was treated, and sodium hydroxide was used as a saponifying agent as in Example 5. Using 20% (o.w.f.) and 5 g / L of a 60% aqueous solution of guanidine phosphate as a saponification accelerator, the bath solution has a bath ratio of 1:20 (mass of polyester fiber: mass of bath solution). Was prepared. Next, the bath temperature was raised from 40 ° C. to 3 ° C./min in a mini-color dyeing tester, and the treatment was performed for 30 minutes after reaching 100 ° C. After the treatment, the mixture was cooled to 80 ° C., the polyester fibers were taken out, washed with water, dehydrated and dried to obtain polyester fibers. For the obtained polyester fiber, the weight loss rate was measured in the same manner as in the case of the acetate fiber. The results are shown in Table 6 below.

<Example 10>
Regarding the bath solution used in the saponification step of Example 6, in order to confirm the weight loss effect on the polyester fiber, 10 g / L of a 30% aqueous solution of guanidine carbonate was used as the saponification accelerator instead of the saponification accelerator of Example 9. Except for this, the same treatment as in Example 9 was carried out to obtain polyester fibers. For the obtained polyester fiber, the weight loss rate was measured in the same manner as in Example 9. The results are shown in Table 6 below.

<Example 11>
Regarding the bath solution used in the saponification step of Example 7, in order to confirm the weight loss effect on the polyester fiber, 5 g / L of a 60% aqueous solution of guanidine sulfamate was used as a saponification accelerator instead of the saponification accelerator of Example 9. The same treatment as in Example 9 was carried out except that the polyester fiber was obtained. For the obtained polyester fiber, the weight loss rate was measured in the same manner as in Example 9. The results are shown in Table 6 below.

<Example 12>
Regarding the bath solution used in the saponification step of Example 8, in order to confirm the weight loss effect on the polyester fiber, 5 g / L of a 60% aqueous solution of guanidine hydrochloride was used as the saponification accelerator instead of the saponification accelerator of Example 9. Except for this, the same treatment as in Example 9 was carried out to obtain polyester fibers. For the obtained polyester fiber, the weight loss rate was measured in the same manner as in Example 9. The results are shown in Table 6 below.

<Comparative Example 3>
The bath liquid used in the saponification step of Comparative Example 2 was treated in the same manner as in Example 9 except that a saponification accelerator was not used in order to confirm the weight loss effect on the polyester fiber, and the acetate fiber cloth was obtained. Obtained.

<Comparative Example 4>
In order to confirm the weight loss effect on the polyester fiber of the bath solution using the quaternary ammonium salt as the saponification accelerator, a quaternary ammonium salt type surfactant was used as a saponification accelerator instead of the saponification accelerator of Example 9. (Marcelin PEL manufactured by Meisei Chemical Works, Ltd.) Polyester fibers were obtained by performing the same treatment as in Example 9 except that 5 g / L was used. For the obtained polyester fiber, the weight loss rate was measured in the same manner as in Example 9. The results are shown in Table 6 below.

As is clear from the results shown in Table 6, Examples 9 to 12 (that is, the bath liquids of Examples 5 to 8) using the guanidine-based compound as the saponification accelerator have almost the effect of promoting weight loss on the polyester fiber. You can see that it is not done. From this, it can be seen that even in the mixed fiber containing the acetate fiber and the polyester fiber, the saponification reaction of the saponifying agent can be selectively promoted with respect to the acetate fiber, and the saponification can be performed to a desired degree of saponification. On the other hand, in Comparative Example 3 (that is, the bath solution of Comparative Example 2), although it has almost no weight loss effect on the polyester fiber, as described above, the acetate fiber cannot be saponified to a desired degree of vinegarization. On the other hand, in Comparative Example 4 in which the quaternary ammonium salt type surfactant was used as the saponification accelerator, the weight loss promoting effect on the polyester fiber was high, and the mixed fiber containing the acetate fiber and the polyester fiber was selectively selected from the acetate fiber. It turns out that the saponification process cannot be performed.

<Comparative Example 5>
In order to confirm whether the guanidine compound can be used as a saponifying agent for acetate fibers, a bath ratio of triacetate long fiber tricot knitted fabric (manufactured by Mitsubishi Chemical Co., Ltd.) was used as a saponifying agent using 5 g / L of a 60% aqueous solution of guanidine phosphate. The bath solution was prepared so as to have a ratio of 1:20 (mass of triacetate long fiber tricot knitted fabric: mass of bath solution). Next, the bath temperature was raised from 40 ° C. to 3 ° C./min in a mini-color dyeing tester, and a saponification step was carried out for 30 minutes after reaching 100 ° C. After the saponification step, the mixture was cooled to 80 ° C., the acetate fiber cloth was taken out, washed with water, dehydrated and dried to obtain an acetate fiber cloth. For the obtained acetate fiber cloth, the weight loss rate was measured in the same manner as in Example 1. The results are shown in Table 7 below.

<Comparative Example 6>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Comparative Example 5, except that 10 g / L of a 30% aqueous solution of guanidine carbonate was used as the saponifying agent instead of the saponifying agent of Comparative Example 5. For the obtained acetate fiber cloth, the weight loss rate was measured in the same manner as in Example 1. The results are shown in Table 7 below.

<Comparative Example 7>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Comparative Example 5, except that 5 g / L of a 60% aqueous solution of guanidine sulfamate was used as the saponifying agent instead of the saponifying agent of Comparative Example 5. For the obtained acetate fiber cloth, the weight loss rate was measured in the same manner as in Example 1. The results are shown in Table 7 below.

<Comparative Example 8>
An acetate fiber cloth was obtained by performing a saponification step in the same manner as in Comparative Example 5, except that 5 g / L of a 60% aqueous solution of guanidine hydrochloride was used as the saponifying agent instead of the saponifying agent of Comparative Example 5. For the obtained acetate fiber cloth, the weight loss rate was measured in the same manner as in Example 1. The results are shown in Table 7 below.

As is clear from the results shown in Table 7, in Comparative Examples 5 to 8 in which the guanidine compound was used without using the anionic compound as the saponifying agent, the weight loss rate of the acetate fiber fabric was very low, and the guanidine compound alone was used. It can be seen that it hardly functions as a saponifying agent.

Claims (10)

A saponification accelerator for diacetate fiber or triacetate fiber containing a guanidine compound .
A saponification accelerator used with a saponification agent containing at least one of sodium hydroxide and potassium hydroxide . The saponification accelerator according to claim 1, wherein the guanidine compound is a guanidine salt. The saponification accelerator according to claim 1 or 2 , wherein the diacetate fiber and the triacetate fiber are in the form of a composite fiber with another fiber. A method for producing an acetate fiber, comprising a saponification step of saponifying at least a part of a diacetate fiber or a triacetate fiber by using a saponifying agent and the saponification accelerator according to any one of claims 1 to 3 . The method for producing an acetate fiber according to claim 4 , wherein in the saponification step, the diacetate fiber or the triacetate fiber is immersed in a solution containing the saponification agent and the saponification accelerator. The method for producing an acetate fiber according to claim 4 or 5 , wherein in the saponification step, the degree of vinegarization of the diacetate fiber or the triacetate fiber is adjusted by adjusting the amounts of the saponification agent and the saponification accelerator used. The method for producing an acetate fiber according to any one of claims 4 to 6 , wherein the diacetate fiber and the triacetate fiber are cloths. The diacetate fiber and the triacetate fiber are in the form of a composite fiber with another fiber, and the produced acetate fiber is a composite fiber with another fiber, any one of claims 4 to 7 . The method for producing an acetate fiber according to. A diacetate fiber or a triacetate fiber comprising a saponification step of saponifying at least a part of the diacetate fiber or the triacetate fiber using the saponifying agent and the saponification accelerator according to any one of claims 1 to 3 . Saponification method. A solution used to saponify diacetate fibers or triacetate fibers to produce acetate fibers.
The solution is a solution containing the saponification accelerator according to any one of claims 1 to 3 and a saponification agent containing at least one of sodium hydroxide and potassium hydroxide.