KR20130015523A - Superabsorbent yarn and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A method for fabricating a superabsorbent thread is provided to ensure satisfying absorption, to prevent harmful material generation, and to minimize elongation reduction. CONSTITUTION: A superabsorbent thread contains a yarn and a superabsorbent agent coated on the yarn. The superabsorbent thread contains crosslinked polyurethane. The superabsorbent agent contains polyurethane of a network structure. The polyurethane is crosslinked with polyacrylic acid, polyacrylamide, or polymethacrylamide. A method for fabricating the superabsorbent thread comprises: a step of preparing a polyurethane dispersion solution; a step of adding a first crosslinking agent to the polyurethane dispersion solution and preparing a coating solution; a step of adding the coating solution into a yarn; a step of performing thermal treatment of the yarn at 50-90 deg. C.; and a step of removing remaining moisture from the yarn.

Description

Superabsorbent Yarn and Method for Manufacturing The Same

The present invention relates to a super absorbent yarn and a method of manufacturing the same, and more particularly, to minimize the decrease in strength and elongation of the seal due to the coating of the superabsorbent material, and to minimize the occurrence of powder that causes difficulties in the manufacturing process of the optical cable. It relates to a super absorbent yarn that can be made and a method of manufacturing the same.

Superabsorbent yarns can be used in the manufacture of optical cables as reinforcing members and water blocking members.

As a method of manufacturing a superabsorbent yarn, there is a method of impregnating a yarn with a water-insoluble superabsorbent material dispersed in water and then performing a drying process. According to this method, however, due to the macromolecular structure of the superabsorbent material, impregnation of the superabsorbent material is lowered, and a yarn having satisfactory absorbency cannot be produced.

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.

Moreover, the conventionally known superabsorbent materials have brittleness, so that the resin layer coated on the seal breaks down when the superabsorbent yarn passes through the guide for the manufacture of the optical cable, resulting in white powder. The occurrence of such powder in the optical cable manufacturing process can lead to product defects.

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

One aspect of the present invention is to provide a superabsorbent yarn which can minimize the generation of powder causing minimization of the process during optical fiber manufacture while minimizing the decrease in strength and elongation of the seal due to the coating of the superabsorbent material.

Another aspect of the present invention is to provide a method for manufacturing a super absorbent yarn which can minimize the generation of powder causing minimization of process during optical fiber manufacture while minimizing the decrease in strength and elongation of the seal due to the coating of the superabsorbent material. will be.

In addition to the above-mentioned aspects of the present invention, other features and advantages of the present invention will be described below, or from such description will be clearly understood by those skilled in the art.

According to an aspect of the present invention as described above, the yarn (yarn) and a superabsorbent material coated on the yarn (superabsorbent material), the superabsorbent yarn is characterized in that it comprises a cross-linked polyurethane Is provided.

According to another aspect of the invention, preparing a polyurethane dispersion; Preparing a coating solution by adding a first crosslinking agent to the polyurethane dispersion; Adding the coating solution to the yarn; Then heat treating the yarn at 50 ° C to 90 ° C; And removing residual moisture from the heat-treated yarn.

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.

According to the present invention, since the superabsorbent material can be provided to the yarn sufficiently and uniformly, the yarn not only has satisfactory absorbency, but also no harmful substances are generated in the manufacturing process which may cause environmental problems. Moreover, the heat treatment of the yarn at a relatively low temperature can minimize the decrease in strength and elongation of the yarn.

In addition, since the superabsorbent material of the present invention provided in the yarn has a relatively flexible property, when the superabsorbent yarn of the present invention is used for manufacturing an optical cable, the possibility of the powder layer breaking down and the generation of powder may be significantly reduced. As a result, by manufacturing the optical cable using the superabsorbent yarn of the present invention, it is possible to reduce the ease of processing and the defective rate.

Hereinafter, a superabsorbent yarn and a method of manufacturing the same according to the present invention will be described in detail.

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 superabsorbent yarn of the present invention includes a yarn and a superabsorbent coated on the yarn.

The yarn may be a continuous multifilament. In particular, considering the function as a reinforcing material, it is preferable that the seal 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.

The superabsorbent of the present invention coated on the yarn comprises a crosslinked polyurethane. Accordingly, the superabsorbents of the present invention have a relatively high flexibility compared to conventional superabsorbents composed solely of ionic polymers having carboxylic acid groups and / or sulfonic acid groups. Thanks to this improved flexibility, the manufacture of an optical cable using the superabsorbent yarn of the present invention can significantly reduce the breakage of the resin layer and the resulting powder generation during its manufacture.

According to the first embodiment of the present invention, the superabsorbent may include a polyurethane having a network structure through crosslinking and may not include an ionic polymer.

According to a second embodiment of the present invention, the superabsorbent may include a polyurethane crosslinked with an ionic polymer such as polyacrylic acid, polyacrylamide, polymethacrylamide, a copolymer of acrylic acid and acrylamide, and the like. In this case, the ionic polymer and the polyurethane are crosslinked together to form a network structure.

Hereinafter, the manufacturing method of the superabsorbent yarn of the present invention will be described in detail.

The method of the present invention comprises the steps of preparing a polyurethane dispersion, adding a first crosslinking agent to the polyurethane dispersion, preparing a coating liquid, adding the coating liquid to a yarn, and heat treating the yarn at 50 ° C to 90 ° C. And removing residual moisture from the heat treated yarn.

The polyurethane dispersion contains water as a dispersion medium, and may further include a second crosslinking agent. The polyurethane dispersion can be purchased or made,

Hereinafter will be described a method for producing a polyurethane dispersion according to an embodiment of the present invention.

First, a polyurethane precursor is prepared by reacting diol with diisocyanate. According to an embodiment of the present invention, the diol is polyethylene glycol (PEG), and the diisocyanate is 1,8-octanediisocianate or hexylmethanediisocianate (HDI). . Specifically, a polyurethane precursor is obtained by mixing the diol and diisocytate in a molar ratio of 1: 1 to 1: 2 and then heating them at 70 to 90 ° C.

The polyurethane precursor dispersion is prepared by adding water to the thus obtained polyurethane precursor and stirring at 500 to 1,500 rpm.

Optionally, before preparing the polyurethane precursor dispersion, the method may further include lowering the viscosity of the polyurethane precursor. For example, the viscosity of the polyurethane precursor can be lowered by adding dibutyltin dilaurate and acetone to the polyurethane precursor so that the ratio of solid content is 20 to 40%. Optionally, the lowered polyurethane precursor can be cooled to about 10 ° C.

Subsequently, the mixture is prepared by adding an aqueous solution in which the second crosslinking agent is dissolved in the polyurethane precursor dispersion, while stirring at 100 to 300 rpm. According to one embodiment of the present invention, diethylenetriamine is used as the second crosslinking agent.

The polyurethane dispersion is then completed by heating the mixture to 40 ° C. to 80 ° C. for 1 to 3 hours. The polyurethane in the dispersion 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.

Subsequently, a coating solution is prepared by adding a first crosslinking agent to the polyurethane dispersion thus prepared.

According to a first embodiment of the present invention, a coating solution is prepared by adding a first crosslinking agent for crosslinking of polyurethanes to the polyurethane dispersion. The first crosslinking agent may be methylenebisacrylamide.

According to a second embodiment of the present invention, a monomer for an ionic polymer in the polyurethane dispersion, an initiator for polymerization of the monomer, and a first for crosslinking the ionic polymer with polyurethane A coating solution is prepared by adding a crosslinking agent.

As the monomer for the ionic polymer, acrylic acid, acrylamide, methacrylamide, and the like may be used. As the initiator, a photopolymerization initiator such as potassium persulfate may be used, and methylenebisacrylamide may be used as the first crosslinking agent. Can be used.

For example, 70-90% acrylamide of the polyurethane solids mass in the polyurethane dispersion, 0.5-2% methylenebisacrylamide of the mass of acrylamide, and a predetermined amount of potassium persulfate are added to the polyurethane dispersion. A coating liquid can be manufactured by adding.

Subsequently, the coating solution prepared as above is added to the yarn. That is, in order to impregnate the coating liquid into the yarn, the yarn is coated with the coating liquid. 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.

Then, the yarn impregnated with the coating liquid is heat-treated so that the polyurethane in the coating liquid can be crosslinked. Through such heat treatment, polyurethanes are crosslinked in the first embodiment of the present invention, and in the second embodiment of the present invention, the polyurethane and the ionic polymer are crosslinked, whereby a superabsorbent material is finally formed on the multifilament. do.

The heat treatment step may be performed by passing a continuous multifilament through a heating unit. According to one embodiment of the invention, the temperature of the heat supply, that is, the heating temperature is 50 to 90 ℃, the time it takes for a predetermined portion of the continuous multi-filament to pass through the heat supply, that is, the heating time is 2 to 5 hours .

Subsequently, residual moisture is removed from the heat treated yarn. The residual moisture may be removed by heating the heat-treated yarn to 100 ° C. or higher under normal pressure or by heating to 80 ° C. or higher under a reduced pressure atmosphere.

According to the present invention, the heat treatment process can be carried out at a temperature lower than the heat treatment temperature (150 ° C. or higher) required to crosslink the water soluble polymer to a degree sufficient to convert the water soluble polymer into a water insoluble material having a high level of water absorption. As a result, not only the decrease in strength and elongation of the seal due to the high temperature heat treatment can be minimized, but the superabsorbent material can be provided even to many kinds of other substrates that can be destroyed by the 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

A polyurethane precursor was prepared by mixing polyethylene glycol and 1,8-octane diisocyanate in a molar ratio of 3: 4 and heating to a temperature of about 80 ° C. The viscosity of the polyurethane precursor was lowered by adding dibutyltin dilaurate and acetone to the polyurethane precursor so that the solid content ratio was 30%. Next, a polyurethane precursor dispersion was prepared by adding distilled water with stirring at 1,000 rpm. A mixture of diethylenetriamine was then added to form a mixture, and the mixture was stirred at about 60 ° C. for 2 hours to prepare a polyurethane dispersion. Subsequently, a coating solution was prepared by adding methylenebisacrylamide to the polyurethane dispersion.

The coating solution was impregnated into the multifilament by dipping a yarn in which continuous aramid multifilaments were spun onto the coating solution thus prepared.

Subsequently, the yarn impregnated with the coating solution was heat-treated at about 70 ° C. for 3 hours so that a superabsorbent material having a network structure formed by crosslinking of polyurethanes was formed in the yarn. The yarn was heated to about 120 ° C. to remove residual moisture to complete the yarn coated with the superabsorbent material.

Example 2

The coating solution was prepared by adding acrylamide, methylenebisacrylamide, and potassium persulfate to the polyurethane dispersion prepared in the same manner as in Example 1.

The coating solution thus prepared was impregnated with the coating liquid by dipping the yarn in which the continuous aramid multifilaments were spliced into the coating liquid, and then the polyfilament impregnated with the coating liquid was heat treated at about 70 ° C. for 3 hours to obtain polyurethane and polyacrylamide. A superabsorbent material having a network structure formed by crosslinking of was formed in the yarn. The yarn was heated to about 120 ° C. to remove residual moisture to complete the yarn coated with the superabsorbent material.

Comparative Example 1

Distilled water was added to 30 wt% aqueous sodium polyacrylate solution (SUBLOC-1000, polymer of hydroxyl) to prepare a final 10% aqueous sodium polyacrylate solution. Subsequently, the aqueous solution was impregnated into the multifilament by dipping the continuous aramid multifilament into the aqueous solution. Subsequently, the multifilament impregnated with the aqueous solution was heat-treated at about 70 ° C. for 3 hours to complete a yarn coated with a super absorbent material.

Comparative Example 2

Sodium polyacrylate aqueous solution was prepared in the same manner as in Comparative Example 1, and then it was impregnated into aramid multifilament. Subsequently, the multifilament impregnated with the aqueous solution was heat-treated at about 200 ° C. for 30 seconds to complete a yarn coated with a super absorbent material.

Absorbency, strength, elongation, and brittleness of the yarns of Examples 1 and 2 and Comparative Examples 1 and 2 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 the following equation.

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

Here, A is the weight of the sample measured with excess water removed, 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.

Brittleness measurement

Since the breakage of the thread causing the powder generation in optical fiber increases as the stiffness of the yarn increases, the breakage of the yarn was indirectly determined by measuring the stiffness of the yarn. The stiffness of the yarn was measured ten times by the method specified in ASTM D885 38, and then the average of the measured values was calculated.

Absorbency (%) Strength (gf / d) Elongation (%) Stiffness (gf) Example 1 200 22 2.91 20 Example 2 256 22 2.80 22 Comparative Example 1 72 22 2.85 29 Comparative Example 2 285 21 2.56 31

Claims (13)

Yarn; And
Including a superabsorbent material coated on the seal,
The super absorbent yarn, characterized in that it comprises a cross-linked polyurethane. The method of claim 1,
The superabsorbent yarn, characterized in that it comprises a polyurethane having a network structure through crosslinking. The method of claim 1,
Wherein said polyurethane is crosslinked with polyacrylic acid, polyacrylamide, or polymethacrylamide. The method of claim 1,
The yarn is a superabsorbent yarn, characterized in that the continuous aramid multifilament. Preparing a polyurethane dispersion;
Preparing a coating solution by adding a first crosslinking agent to the polyurethane dispersion;
Adding the coating solution to the yarn;
Then heat treating the yarn at 50 ° C to 90 ° C; And
And removing residual moisture from the heat-treated yarn. The method of claim 5,
Preparing the polyurethane dispersion,
Reacting diol with diisocyanate to prepare a polyurethane precursor;
Preparing a polyurethane precursor dispersion by adding water to the polyurethane precursor;
Preparing a mixture by adding an aqueous solution in which a second crosslinking agent is dissolved in the polyurethane precursor dispersion;
And heating the mixture to 40 ° C to 80 ° C. The method according to claim 6,
Preparing the polyurethane dispersion,
Before preparing the polyurethane precursor dispersion, the method of producing a super absorbent yarn, characterized in that further comprising the step of lowering the viscosity of the polyurethane precursor. The method of claim 7, wherein
The step of lowering the viscosity of the polyurethane precursor is a method for producing a super absorbent yarn, characterized in that the addition of dibutyltin dilaurate (dibutyltin dilaurate) and acetone to the polyurethane precursor. The method according to claim 6,
The diol is polyethylene glycol,
And said diisocyanate is hexyl methane diisocyanate or 1,8-octane diisocyanate. The method according to claim 6,
And said second crosslinking agent is diethylenetriamine. The method of claim 5,
And said first crosslinking agent is methylenebisacrylamide. 12. The method of claim 11, wherein acrylamide is further added to the polyurethane dispersion for the preparation of the coating solution. The method of claim 12,
Potassium persulfate is further added to the polyurethane dispersion for the preparation of the coating solution, characterized in that the manufacturing method of the superabsorbent yarn.