KR101366907B1 - Method for Manufacturing Superabsorbent-Coated Yarn - Google Patents

Abstract

Disclosed is a method of manufacturing a yarn coated with a super absorbent material, which can minimize the decrease in strength and elongation of the seal due to the coating of the super absorbent material and can improve productivity and reduce energy. The preparation method of the present invention comprises the steps of preparing a semi-crosslinked superabsorbent precursor dispersed solution-wherein the semi-crosslinked superabsorbent precursor precursor is a polymer having a crosslinking degree of 20 to 80% A polymer that is only converted into a superabsorbent material through additional crosslinking, coating the yarn with the dispersion, and allowing the superabsorbent material precursor to be fully crosslinked to form a superabsorbent material. Heating the coated yarn.

Description

Method for manufacturing yarn coated with super absorbent material {Method for Manufacturing Superabsorbent-Coated Yarn}

The present invention relates to a method of manufacturing a yarn coated with a super absorbent material, and more particularly, to minimize the decrease in strength and elongation of the seal due to the coating of the super absorbent material, and to improve productivity and reduce energy. The present invention relates to a method for producing a yarn coated with an absorbent material.

Yarns coated with superabsorbent materials can be used to make cables for optical communications, in which case they function as reinforcing members and water blocking members.

As a method of manufacturing a yarn coated with a super absorbent material, there is a method of impregnating a water-insoluble superabsorbent material dispersed in water into a yarn and then performing a drying process. However, according to this method, a yarn having satisfactory absorbency cannot be produced due to the impregnation decrease due to the high viscosity.

A method for improving impregnation is disclosed in US Pat. No. 5,635,569. According to this, a yarn coated with a superabsorbent material is prepared by impregnating the water-in-oil emulsion containing a superabsorbent material in an aqueous phase and then performing a drying process. However, this method also has a significant drawback. That is, additional equipment and costs for the treatment of these harmful substances are further required because environmentally problematic substances such as isohexadecane are released during the drying process.

To solve the above problem, U.S. Pat.No. 5,100,397, U.S. Pat.No.6,319,558, and U.S. Pat.No.6,284,367 provide a coating or coating of an aqueous solution comprising a water-soluble crosslinkable polymer. After impregnation, a method of converting the water-soluble polymer into a water-insoluble superabsorbent material by crosslinking the water-soluble polymer is proposed.

This method requires that the yarn undergo a high temperature heat treatment for a long time in order to crosslink the water-soluble polymer, which is not crosslinked at all, to a degree sufficient to form a high level of water-insoluble material. However, if a high temperature heat treatment is performed for a long time, damage to the yarn is caused, which causes a decrease in strength and elongation of the yarn. The decrease in strength and elongation of the yarn to be used as reinforcement for the optical cable is fatal. Moreover, the longer the heat treatment time of the high temperature is economically disadvantageous, such as productivity is lowered and energy use is increased.

Accordingly, the present invention relates to a method of manufacturing a yarn coated with a super absorbent material which can prevent the problems caused by the above limitations and disadvantages of the related art.

One aspect of the present invention is to provide a method of manufacturing a yarn coated with a super absorbent material which can minimize the decrease in strength and elongation of the seal due to the coating of the super absorbent material and can improve productivity and reduce energy.

Other features and advantages of the invention will be set forth in the description which follows, or may be learned by those skilled in the art from the description.

In accordance with an aspect of the present invention as described above, preparing a semi-crosslinked superabsorbent precursor dispersed solution (semi-crosslinked superabsorbent precursor dispersed solution)-wherein the semi-crosslinked superabsorbent material precursor is 20 to 80% crosslinking degree A polymer having a polymer which is finally converted to a super absorbent material through further crosslinking; Coating a seal with the dispersion; And heating the yarn coated with the dispersion such that the superabsorbent material precursor is completely crosslinked to form a superabsorbent material.

The foregoing general description of the present invention is intended to be illustrative of or explaining the present invention, but does not limit the scope of the present invention.

Providing the superabsorbent material to the yarn according to the method of the present invention will not only have satisfactory absorbency because the superabsorbent material can be provided sufficiently and uniformly to the yarn, but also cause environmental problems during its manufacture. No hazardous substances are generated. In addition, the time required for the high temperature heat treatment process is minimized, thereby minimizing the decrease in strength and elongation of the seal, and at the same time improving productivity and saving energy.

Hereinafter will be described in detail a method for producing a yarn coated with a super absorbent material according to the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

The method includes preparing a dispersion of semi-crosslinked superabsorbent material precursor, coating the yarn with the dispersion, and heating the yarn coated with the dispersion.

As used herein, the term 'crosslinked superabsorbent material precursor' refers to a polymer having a degree of crosslinking of 20 to 80%, which is converted into a superabsorbent material only through further crosslinking. That is, the semi-crosslinked superabsorbent material precursor itself does not have the high absorbency required for the waterproofing material but has a water-insoluble property because it has a crosslinking degree of 20 to 80%.

If the degree of crosslinking is less than 20%, there is a limit to alleviating the heating conditions of the subsequent heat treatment process, and due to heat treatment under severe conditions, it is not possible to significantly reduce the strength and elongation of the yarn. On the other hand, when the degree of crosslinking exceeds 80%, the viscosity of the dispersion becomes too high, making it impossible to uniformly impregnate the precursor in the yarn.

According to one embodiment of the invention, a monomer having a carboxylic acid group and / or a sulfonic acid group, for example acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, or a mixture thereof is dissolved in water. An aqueous solution comprising 0.1 to 50% by weight of monomer is prepared. Subsequently, the monomer is partially neutralized such that at least some of the acid groups, for example 20 to 80 mole%, are present as alkali metal salts such as sodium, potassium and the like. Alkali metal hydroxides such as sodium hydroxide can be used as suitable neutralizing agents. The aqueous solution may include alkylol methacrylamide, iron salt, aluminum salt, zirconium salt, or a mixture thereof as a crosslinking agent.

Other useful monomers that can be used to obtain semi-crosslinked precursors include acrylamide, methacrylamide, maleic acid, maleic anhydride, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxy Propyl methacrylate, glycidyl methacrylate, dimethylaminoalkylmethacrylate, and dimethylaminopropyl acrylamide.

By slowly stirring the aqueous solution at a temperature of 150 ℃ for 1 to 24 hours, it is possible to prepare a dispersion of semi-crosslinked superabsorbent material precursor. Since the semi-crosslinked superabsorbent material precursor is insoluble in water, the semi-crosslinked superabsorbent material precursor is not dissolved in water, which is a dispersion medium, and is uniformly dispersed therein.

According to one embodiment of the invention, the precursor content in the dispersion is 0.1 to 50% by weight. If the content of the precursor is less than 0.1% by weight, it is difficult to control the degree of crosslinking of the precursor, and it is difficult to impart high absorbency to the yarn. On the other hand, if the content of the precursor exceeds 50% by weight, there is a problem in that the coating is not uniform and workability is difficult because the viscosity is too high.

The semi-crosslinked superabsorbent material precursor of the present invention has a mean particle diameter of 1 to 1,000 nm. The average particle diameter may be obtained by measuring the particle diameter ten times using a laser particle size analyzer (LS230, Culter, USA) and then averaging the measured values.

According to one embodiment of the invention, the semi-crosslinked superabsorbent material precursor is i) polyacrylic acid, ii) polymethacrylic acid, iii) copolymer of acrylic acid and acrylamide, or iv) derivatives thereof.

If a crosslinking agent is added to the aqueous solution of the monomer, through the above semi-crosslinking process, only a part of the crosslinking agent may participate in the crosslinking reaction, and the rest may remain in the resulting dispersion without participating in the crosslinking reaction.

Once a dispersion of semi-crosslinked superabsorbent material precursor is prepared, the yarn is coated with the dispersion to impregnate the dispersion into the yarn. Various coating methods can be used, such as a painting method, a rolling method, a printing method (ie, dot printing method), a spray method, a brush method, a swabbing method, or a dip coating method.

The yarn may comprise a continuous multifilament. In particular, when considering the function as a reinforcing material, it is preferable that the multifilament is a high strength multifilament. Thus, the yarns of the present invention may be formed of aramid, ultra high molecular weight polyethylene, or polybenzoxazole.

Optionally, the yarn may comprise a continuous aramid multifilament consisting of 1 to 20,000 monofilaments and having a linear density of 50 to 1,500 denier. One multifilament may constitute a yarn alone, but a plurality of multifilaments may be spliced together to form one yarn.

Once the coating is complete, the yarn coated with the dispersion is heated so that the semi-crosslinked precursor impregnated in the yarn can be fully crosslinked to form a superabsorbent material having satisfactory absorbency.

The heating step may be performed by passing a continuous multifilament through a heating unit. The temperature of the heat supply portion, that is, the heating temperature is 100 to 150 ° C., and the time taken for the predetermined portion of the continuous multifilament to pass through the heat supply portion, that is, the heating time is 10 to 30 seconds.

The heating temperature and / or heating time may be adjusted according to the degree of crosslinking of the superabsorbent material precursor impregnated in the multifilament. That is, the higher the degree of crosslinking may lower the heating temperature or reduce the heating time.

According to the present invention, since the superabsorbent material precursor impregnated in the multifilament is in a semi-crosslinked state, the heating conditions required for crosslinking to a degree sufficient to convert a polymer that is not crosslinked into a water-insoluble material having a high level of absorbency. The heating process can be carried out under even more relaxed conditions, i.e. under low heating temperatures and / or short heating times. As a result, the time required for the high temperature heat treatment process can be minimized to minimize the decrease in strength and elongation of the seal, and the manufacturing speed can be increased to achieve productivity improvement and energy saving. In addition, since the present invention can lower the heat treatment temperature, it has the advantage that it is possible to provide a super absorbent material even to many kinds of other substrates that can be destroyed by high temperature heat treatment.

Hereinafter, the effects of the present invention will be described in more detail through Examples and Comparative Examples. The embodiments exemplified below are merely to aid the understanding of the present invention and do not limit the scope of the present invention.

Example 1

Distilled water was added to 30% by weight aqueous solution of sodium polyacrylate (SUBLOC-1000, hydroxyl polymer) to prepare a 10% aqueous solution of sodium polyacrylate, which was stirred at 150 ° C. for 30 minutes to obtain a high crosslinking degree of 50%. A dispersion of absorbent material precursor was prepared.

The dispersion was impregnated with the dispersion by dipping continuous aramid multifilament into the dispersion. Subsequently, the multifilament was passed through an oven maintained at 150 ° C., but a predetermined portion of the multifilament was allowed to pass through the oven in 20 seconds to complete a yarn coated with a super absorbent material.

Example 2

A dispersion of the superabsorbent material precursor was prepared in the same manner as in Example 1 except that the sodium polyacrylate aqueous solution was stirred at 150 ° C. for 20 minutes so that the superabsorbent material precursor had a crosslinking degree of 20%. This dispersion was then used to complete a yarn coated with a superabsorbent material in the same manner as in Example 1.

Example 3

A dispersion of the superabsorbent material precursor was prepared in the same manner as in Example 2. Subsequently, the dispersion was impregnated with the dispersion by dipping continuous aramid multifilament into the dispersion. Subsequently, the multifilament was passed through an oven maintained at 150 ° C., but a predetermined portion of the multifilament was allowed to pass through the oven in 30 seconds to complete a yarn coated with a super absorbent material.

Example 4

A dispersion of the superabsorbent material precursor was prepared in the same manner as in Example 1 except that the sodium polyacrylate aqueous solution was stirred at 150 ° C. for 40 minutes so that the superabsorbent material precursor had a degree of crosslinking of 80%. This dispersion was then used to complete a yarn coated with a superabsorbent material in the same manner as in Example 1.

Example 5

A dispersion of the superabsorbent material precursor was prepared in the same manner as in Example 4. Subsequently, the dispersion was impregnated with the dispersion by dipping continuous aramid multifilament into the dispersion. Subsequently, the multifilament was passed through an oven maintained at 150 ° C., but a predetermined portion of the multifilament was allowed to pass through the oven in 10 seconds to complete a yarn coated with a super absorbent material.

Comparative Example 1

A dispersion of the superabsorbent material precursor was prepared in the same manner as in Example 1 except that the sodium polyacrylate aqueous solution was stirred at 200 ° C. for 60 minutes to make the superabsorbent material precursor have a degree of crosslinking of 90%. This dispersion was then used to complete a yarn coated with a superabsorbent material in the same manner as in Example 5.

Comparative Example 2

Distilled water was added to 30% by weight aqueous solution of sodium polyacrylate (SUBLOC-1000, hydroxyl polymer) to prepare a final solution of sodium polyacrylate at a concentration of 10%. Subsequently, the aqueous solution was impregnated into the multifilament by dipping the continuous aramid multifilament into the aqueous solution. Subsequently, the multifilament was passed through an oven maintained at 150 ° C., but a predetermined portion of the multifilament was allowed to pass through the oven in 30 seconds to complete a yarn coated with a super absorbent material.

Comparative Example 3

Except that the temperature of the oven was maintained at 200 ℃ to complete the yarn coated with a super absorbent material in the same manner as in the above comparison 2.

Absorbency, strength, elongation, and coating layer uniformity of the yarns of Examples 1-5 and Comparative Examples 1-3 prepared as described above were measured by the following methods, and the results are shown in Table 1 below.

Absorbency Measurement of Thread

2 g of the actual sample was taken, cut into uniform lengths of about 2 cm, and then immersed in 500 mL of 20 ° C distilled water for 2 minutes each. Excess water was removed from the completely wet samples by centrifugation (2000 rpm, 1 min). After weighing the samples each having excess water removed, the samples were hot air dried in an oven at 110 ° C. for 24 hours. After measuring the weight of each dried sample, the absorbency of the yarn was calculated using Equation 1 below.

Equation 1: Absorbency of yarn (%) = [(A-B) / B] × 100

Here, A is the weight of the sample measured in the state of excess water removed after dipping in distilled water, B is the weight of the sample measured after hot air drying.

Measurement of strength and elongation of yarn

In accordance with the ASTM D885 specification, the Instron Engineering Corp. (Canton, Mass) was stretched until a 25 cm long sample was broken, and then the strength and elongation at the fracture point were determined. At this time, the tensile velocity was 300 mm / min, and the initial load was fineness x 1/30 g. After repeating this process five times, the average value was obtained.

Coating layer uniformity measurement

Coating layer uniformity on the yarn was indirectly confirmed from the error of the coating layer content ratio.

First, unwinding the yarn wound on the branch pipe and taking 10 samples at 10g intervals at 1m intervals, each sample was dried at 105 ℃ for 2 hours and then weighed. The dried sample was treated with CCl ₄ to obtain a sample in which the coating layer was removed and only the aramid multifilament remained. The sample was dried at 105 ° C. for 2 hours and then weighed. Subsequently, the coating layer content ratio of each sample was calculated using Equation 2 below.

Equation 2: Content Ratio of Coating Layer (%) = [(W1-W2) / W1] × 100

Here, W1 is the weight of the sample before the coating layer is removed, and W2 is the weight of the sample from which the coating layer is removed.

After calculating the average and the error from the coating layer content ratios of the samples thus calculated, the error of the coating layer content ratio was calculated using Equation 3 below.

Equation 3: Coating Layer Content Error (%) = (X / Y) × 100

Where X is the standard deviation of the coating layer content ratio and Y is the average of the coating layer content ratio.

Absorbency (%) Strength (gf / d) Elongation (%) Coating layer content error (%) Example 1 261 21 2.72 10.21 Example 2 254 21 2.73 8.90 Example 3 259 20 2.58 7.68 Example 4 225 21 2.69 11.36 Example 5 220 22 2.85 12.01 Comparative Example 1 191 22 2.76 29.96 Comparative Example 2 113 20 2.50 5.61 Comparative Example 3 133 19 2.43 6.06

Claims (8)

Preparing a semi-crosslinked superabsorbent precursor dispersed solution, wherein the semi-crosslinked superabsorbent precursor is a polymer having a degree of crosslinking of 20 to 80%. Polymers which are only converted to superabsorbent materials through further crosslinking;
Coating a seal with the dispersion; And
And heating the yarn coated with the dispersion such that the superabsorbent material precursor is completely crosslinked to form a superabsorbent material. The method of claim 1,
Said semi-crosslinked superabsorbent material precursor has a mean particle diameter of 1 to 1,000 nm. The method of claim 1,
The yarn comprises a continuous multifilament,
The heating step is carried out by passing the continuous multifilament through a heating unit,
The heat supply unit is maintained at 100 to 150 ℃,
And a time required for the predetermined portion of the continuous multifilament to pass through the heat supply part is 10 to 30 seconds. The method of claim 3,
The continuous multi-filament is aramid multi-filament, characterized in that the superabsorbent material coating method of the yarn. The method of claim 1,
The semi-crosslinked superabsorbent material precursor is i) polyacrylic acid, ii) polymethacrylic acid, iii) a copolymer of acrylic acid and acrylamide, or iv) derivatives thereof. Manufacturing method. The method of claim 1,
The dispersion is a method of manufacturing a yarn coated with a super absorbent material, characterized in that it comprises water as a dispersion medium. The method according to claim 6,
The dispersion is a method of manufacturing a yarn coated with a super absorbent material, characterized in that it further comprises a crosslinking agent. The method of claim 7, wherein
Said crosslinking agent is alkylol methacrylamide, iron salt, aluminum salt, zirconium salt, or a mixture thereof.