JPH05272056A - Internally hydrophilized cellulosic fiber - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having improved water-absorption without deteriorating the unique feeling of a cellulosic fiber used as a raw material by hydrophilizing the inner part of a cellulosic fiber with a specific hydrophilic group. CONSTITUTION:The objective hydrophilic cellulosic fiber having hydrophilized inner part can be produced e.g. by immersing a cotton sliver in a glycidol (e.g. 3-epoxy-1-propanol) or monochloroacetic acid (for carboxymethylation) to effect the addition reaction in such a manner as to increase the substitution degree of the hydrophilic group from the outside of the fiber toward the core part. The obtained hydrophilic cellulosic fiber has a hydrophilic group substitution degree of 0.01-0.5 and a water-absorptivity of 40-100%. Since the surface part of the fiber has the properties of original cellulosic fiber, it is suitable as a material for sports wear, diaper, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellulosic fiber having a higher water-absorbing performance than conventional cotton and other cellulosic fibers, and yet maintaining the original softness of cotton or cellulosic fiber. So, not only as a material for ordinary clothes and underwear, but also as a material for sports clothes, work clothes, or diapers that require high water absorption, diaper covers, bed sheets for bedridden elderly, etc. it can.

[0002]

2. Description of the Related Art Cotton is a natural fiber made of cellulose, but unlike hemp fibers such as potatoes (ramie) and flax (linen), which are also composed of cellulose, absorb water,
It is highly hygroscopic. This is due to the unique fiber structure of cotton.

[0003] In particular, there is a hollow portion called a lumen inside the fiber, and it is known that water molecules are absorbed through the lumen and small pores in the tissue and show high hydrophilicity.

Under these circumstances, there have been relatively few studies on the hydrophilization of cotton fibers, and studies on the production of superabsorbent fibers / resins, superabsorbent nonwoven fabrics, ionic dye dyeable fibers and the like have been conducted. Nothing more than.

As the chemical treatment for hydrophilization, carboxymethylation with monochloroacetic acid, which is also used in the present invention, is known.

However, the hydrophilization of the fiber surface by chemical treatment was a method having a high reactivity and sacrificing the original soft feeling of the cellulosic fiber.

In the present invention, no attempts have been made to convert the cellulosic fibers described below in the present invention, typically cotton fibers, into clothing fibers having higher water absorption without impairing the natural texture and fiber performance peculiar to cotton fibers.

[0008]

With the high degree of hydrophilicity obtained by the chemical treatment of cellulosic fibers such as cotton up to now, the soft feel of the cellulosic fibers is impaired and the touch becomes poor. Therefore, in the present invention, While maintaining the original texture and soft feel of the cellulosic fiber on the outside, by improving only the water absorption and moisture absorption performance and adjusting the degree of hydrophilicity to a slight degree, especially sports clothing materials and highly absorbent sheets, etc. The purpose is to give practicality to.

The super absorbent cotton, for example, intended by the present invention is a fiber exhibiting a water absorbency of about 10 to 90% higher than that of untreated cotton.

This is because it is considered that if the hydrophilization treatment is further performed, the mechanical strength is largely reduced and the feeling peculiar to the cotton fiber is impaired, so that it is not suitable as a clothing fiber.

In fact, the sample having a water absorption higher than that of the untreated cotton by 100% or more has a remarkable change in appearance and the texture of the cotton fiber.

[0012]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have earnestly studied and, as a result, arrived at the present invention.

That is, according to the present invention, (1) a cellulosic fiber is hydrophilized inside the fiber,
Outside, without damaging the original texture of cellulosic fiber,
Cellulosic fiber with improved water absorption performance,

(2) The hydrophilic group for making hydrophilic is a glycidol group, the substitution degree of the hydrophilic group of the cellulosic fiber is 0.05 to 0.5, and the water absorption is 40% to 100% ( 1) The cellulosic fiber described.

(3) The hydrophilic group for hydrophilization is a carboxymethyl group, the substitution degree of the hydrophilic group of the cellulosic fiber is 0.01 to 0.045, and the water absorption is 40% to 100%.
(1) The cellulosic fiber according to item (1).

(4) The cellulosic fiber according to (1), wherein the distribution of the degree of substitution of hydrophilic groups increases from the surface of the fiber toward the center.

(5) The cellulosic fiber according to (1), wherein there is a difference between the degree of hydrophilicity of the surface layer of the fiber and the degree of hydrophilicity of the inside thereof.

(6) The cellulosic fiber according to (1), wherein the hydrophilicity of the surface layer of the fiber is substantially the same as the hydrophilicity of the surface layer of the untreated fiber.

More specifically, in the present invention, the cotton or other cellulosic fiber is sufficiently dipped (30 minutes or more) in a 2,3-epoxy-1-propanol (glycidol) solution or a monochloroacetic acid solution, and then the fiber 2,3-epoxy-1-propanol (glycidol) or monochloroacetic acid adhering to the outer part of is washed and removed by immersing it in a solvent of the same type as the solvent used for a short time of 10 seconds to 1 minute, 0.1% to 50% in the same solvent as it is
By immersing the sample in a solution of sodium hydroxide at a concentration and adding the hydrophilic groups so that the degree of substitution of the hydrophilic groups increases from the outside to the center of the fiber at 30 ° C to 100 ° C. It is a fiber-treated product in which the inside of the obtained cellulosic fiber is positionally and selectively hydrophilized, and the outside is characterized in that only the water absorption performance is improved without impairing the original texture and feel of the cellulosic fiber.

When glycidol is used as the hydrophilizing agent, the hydrophilic group is a nonionic glycidol group, and when monochloroacetic acid is used, the hydrophilic group is an ionic carboxymethyl group.

Specific examples will be given below. The method for measuring the water absorption rate referred to here is to calculate the water absorption rate by immersing the sample in distilled water for about 2 hours, placing it in a centrifuge, dehydrating it at 4000 rpm for 4 minutes, and weighing it.

[0022]

[Equation 1] W ₁ : Weight of sample after centrifugal dehydration W ₀ : Weight of sample with constant weight under the environment of 20 ° C. and 65% RH

[0023]

Example 1 5 g of cotton sliver (length 25-35 mm, average fineness 1.9d) was immersed in 0.5% sodium hydroxide aqueous solution to wash and remove impurities, and then glycidol 2
It is immersed in 200 g of an aqueous solution having a concentration of 8.6% to 54.5% for 24 hours.

Then, the glycidol attached to the fiber surface was
Immerse in 00 cc of water for 30 seconds to wash and remove, then in 300 cc of 2% aqueous sodium hydroxide solution (temperature: 50 ° C)
The mixture is reacted at (± 2 ° C) for 1 hour to remove unreacted substances by washing.

Acetone solution may be used instead of the aqueous solution by the same procedure.

The water absorption of the internally hydrophilized cotton obtained in each case was as follows.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

Example 2 5 g of cotton sliver (length 25-35 mm, average fineness 1.9d) was immersed in a 0.5% aqueous sodium hydroxide solution to remove impurities, and then 200 g of 50% glycidol-acetone solution. Soak in for 2 hours.

Then, the glycidol attached to the fiber surface was
It is soaked in 00 cc of acetone for 30 seconds to be removed by washing, and is allowed to react for 1 hour in 300 cc of acetone containing 20 cc of 2% aqueous sodium hydroxide solution (temperature 50 ° C. ± 2 ° C.), and then unreacted substances are removed by washing.

By repeating the same operation once to three times, three kinds of internally hydrophilized samples having different hydrophilization rates can be obtained.

At this time, the water absorption rate of the totally hydrophilized sample obtained without washing and removing the glycidol attached to the fiber surface is shown in the table below. Although the water absorption rate of the whole sample is large, the reaction proceeds to the surface. The texture was hard due to the fact that he was out.

[0033]

[Table 3]

[0034]

Example 3 5 g of a cotton sliver (length 25 to 35 mm, average fineness 1.9d) is immersed in 300 cc of 33% monochloroacetic acid / acetone solution for 2 hours.

Thereafter, the monochloroacetic acid on the fiber surface was immersed in 300 cc of acetone for 30 seconds to be washed and removed,
As it is, in 2.0 liter of acetone solution (Temperature 50 ° C ± 2
The sample is dipped in (.degree. C.), then added so that the concentration of sodium hydroxide is 0.1% to 0.8% and reacted for 1 hour to carboxymethylate the cotton cellulose.

Then, by washing away the unreacted material, five kinds of internally hydrophilized samples having different hydrophilization rates could be obtained.

At this time, the water absorption rate of the totally hydrophilized sample obtained without washing and removing the monochloroacetic acid on the fiber surface is shown in the following table. There was a difference in performance, and the texture was hard.

[0038]

[Table 4]

[0039]

Example 4 5 g of cotton sliver (length 25 to 35 mm, average fineness 1.9d) is immersed in 500 cc of 45% monochloroacetic acid / water solution for 2 hours.

Thereafter, the monochloroacetic acid on the fiber surface was immersed in 1000 cc of water for 30 seconds for washing and removal, and the sample was immersed in a squeeze (pickup rate 80%) so that the weight of the cotton sliver was 9 g, and then 7 to 40. % Sodium hydroxide solution (20 cc) at 50 ° C. for 1 hour,
Carboxymethylate cotton cellulose.

Then, by removing the unreacted material by washing, four types of internally hydrophilized samples having different hydrophilization rates could be obtained.

At this time, the water absorption rate of the totally hydrophilized sample obtained without washing and removing the monochloroacetic acid on the fiber surface is shown in the following table. There was a difference in performance, and the texture was hard.

[0043]

[Table 5]

[0044]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a fiber having a higher water absorption without deteriorating the natural feeling peculiar to the cellulosic fiber.

Claims (6)

[Claims] 1. A cellulosic fiber in which the inside of the cellulosic fiber is made hydrophilic and the outside has improved water absorption performance without impairing the original texture of the cellulosic fiber. 2. The hydrophilic group for making hydrophilic is a glycidol group, and the substitution degree of the hydrophilic group of the cellulosic fiber is 0.0.
The cellulosic fiber according to claim 1, which has a water absorption of 5% to 0.5% and 40% to 100%. 3. The hydrophilic group for hydrophilization is a carboxymethyl group, the substitution degree of the hydrophilic group of the cellulosic fiber is 0.01 to 0.045, and the water absorption is 40% to 100%. Item 1. The cellulosic fiber according to item 1. 4. The cellulosic fiber according to claim 1, wherein the substitution degree distribution of hydrophilic groups increases from the surface of the fiber toward the center. 5. The cellulosic fiber according to claim 1, wherein there is a difference between the degree of hydrophilicity of the surface layer of the fiber and the degree of hydrophilicity of the inside thereof. 6. The cellulosic fiber according to claim 1, wherein the degree of hydrophilicity of the surface layer of the fiber is substantially the same as the degree of hydrophilicity of the surface layer of the untreated fiber.