WATER BASED BOND SEWING THREAD AND METHOD OF MANUFACTURING THE SAME

Abstract

A method of manufacturing a bonded sewing thread comprises the steps of forming coating liquid by adding catalyst of 1 to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt % (MW is 222.2 and viscosity is 500 to 1000 CPS/25° C.), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (MW is 400 to 500 and viscosity is 500 to 1000 CPS/25° C.), and water of 49 to 53 wt % are uniformly mixed; coating the sewing thread by dipping the sewing thread in the mixed coating liquid; a dry step of drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds; curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and winding the elongated sewing thread.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a water based bond sewing thread and a method of manufacturing the same. More particularly, the present invention relates to a water based bond sewing thread and a method of manufacturing the same, in which a risk of fading and a change of color is remarkably decreased and color reproducibility and a feeling of use are excellent even for a long time use, working environments can be improved and a risk of a fire is low because a water based coating method not generating any toxic gases is used, additional process is not used in case where waterproof thread is manufactured by using water based bond sewing thread, and water treatment can be easily performed because some waterproof liquid can be mixed in a process of coating the sewing thread.

2. Background of the Invention

In general, sewing thread refers to a thread used in a sewing machine. The sewing thread is subjected to a dyeing process and produced after a winding process.

However, the common sewing thread is problematic in that the strength of the thread is weak, the thread gets loose or entangled at a high-speed sewing task, and textiles are damaged because of friction.

In order to solve the problems, a bonded sewing thread is provided by performing a bonding process on sewing thread. There is also provided waterproof sewing thread produced by performing additional waterproof processing on a bonded sewing thread in order to prevent water from infiltrating into the sewing thread, according to circumstances.

A solvent based method is used in the existing bonding processing method. Raw materials for the bonding processing include albamide, ethylene glycol, and methyl alcohol which are agitated and used. The raw materials need to continuously heated and agitated.

Furthermore, in a process of coating the sewing thread, the materials need to be continuously heated in order to prevent the materials from being hardened. After the padding processing is performed as described above, dry, elongation, winding, and packaging processes are performed.

In case where waterproof sewing thread is fabricated as described above, after the dry and elongation processes are completed, a process of applying additional water repellents and another dry process need to be performed.

Furthermore, the existing sewing thread is problematic in that feeling is hard because of a lack of flexibility, some toxic gases are generated and a risk of a fire resulting from the volatilization of methyl alcohol exists when the bonding process is performed on the sewing thread, methanol needs to be frequently added and a dual heating device is needed because a solvent is volatile, and an additional agitator needs to be installed.

In addition, a feeling of use and a feeling of coloring are decreased because there is a great change in the color between before the thread is dyed and after the thread is processed. Accordingly, an additional device is required because second water repellent processing has to be performed after dry and elongation processes. In particular, there is a problem in that the cost rises because the dependency of imported raw materials is high.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in view of the above problems occurring in the prior art, and the present invention provides a bonded sewing thread in which flexibility is excellent, durability and strength are high and freely controlled, a risk of fading and a change of color is remarkably decreased and color reproducibility and a feeling of use are excellent even for a long time use, the manufacturing cost is low, and a supplied price is economical.

Furthermore, the present invention provides a bonded sewing thread in which working environments can be improved and a risk of a fire is low because a water based coating method not generating any toxic gases is used, additional process is not used in case where waterproof thread is manufactured by using water based bond sewing thread, and water treatment can be easily performed because some waterproof liquid can be mixed in a process of coating the sewing thread.

According to an aspect of the present invention, there is provided a method of manufacturing a bonded sewing thread, comprising a coating liquid formation step of forming coating liquid by adding catalyst of 1 to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed; a padding step of coating the sewing thread by dipping the sewing thread in the mixed coating liquid; a dry step of drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds; a curing step of curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; an elongation step of elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and a winding step of winding the elongated sewing thread.

According to another aspect of the present invention, there is provided a bonded sewing thread manufactured by coating the sewing thread by dipping the sewing thread in coating liquid, produced by mixing catalyst of 1 to 5 wt % and a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed; drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds; curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and winding the elongated sewing thread.

In accordance with water based bond sewing thread and the method of manufacturing the same according to the present invention, there are advantages in that flexibility is excellent, durability and strength are high and freely controlled, a risk of fading and a change of color is remarkably decreased and color reproducibility and a feeling of use are excellent even for a long time use, the manufacturing cost is low, and a supplied price is economical.

Furthermore, there are advantages in that working environments can be improved and a risk of a fire is low because a water based coating method not generating any toxic gases is used, additional process is not used in case where waterproof thread is manufactured by using water based bond sewing thread, and water treatment can be easily performed because some waterproof liquid can be mixed in a process of coating the sewing thread.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a bonded sewing thread and a method of manufacturing the same according to the present invention are described in detail.

In the method of manufacturing the bond sewing thread, a coating liquid formation process is performed to form coating liquid by adding catalyst of 1 to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, from among polyester materials, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed.

A padding process is performed to coat the sewing thread by dipping the sewing thread in the mixed coating liquid.

A dry process is performed to dry the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds.

A curing process is performed to cure the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; an elongation process of elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60 W.

A winding process is performed to wind the elongated sewing thread.

The above method is described below in more detail.

First, in the coating liquid formation process, the coating liquid is formed by adding catalyst of 1 to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed.

A main material for the coating liquid is polyester. In order to increase an adhesive property, aliphatic isophthalic diisocyanate (that is, a non-yellow characteristic cross-linking agent) of 7 to 11 wt % (where, a molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)) is added.

In case where aliphatic isocyanate of less than 7 wt % is mixed, the adhesive strength of the coating liquid is low. In case where aliphatic isocyanate of more than 11 wt % is mixed, the viscosity of the coating liquid is high and so workability is low. Accordingly, aliphatic isocyanate of 7 to 11 wt % preferably is mixed.

In order to make the coating liquid water-based, polyester sulfur oxide diol (that is, a water based monomer material) of 1 to 5 wt % having an MW of 400 to 500 and viscosity of 500 to 1000 CPS/25° C. (Brookfield viscometer) (where, wt % is not a known art) is adeed. Further, water of 49 to 53 wt % is added as a diluent for controlling viscosity.

The reason why water is added is that water serves as a diluent and the padding process may not be properly performed because the main material has a high viscosity.

In case where water of less than 49 wt % is mixed, viscosity is high and so workability is difficult. In case where water of more than 53 wt % is mixed, there is a possiblity that the adhesive strength of the coating liquid may be low. Accordingly, water of 49 to 53 wt % preferably is added.

The catalyst of 1 to 5 wt % is added, preferably 2 wt %. The catalyst functions to rapidly dry the coating liquid padded to the bond sewing thread and to control the strength of the bond sewing thread. The amount of the catalyst mixed can be various according to circumstances. In case where the catalyst of less than 1 wt % is mixed, the strength of the bond sewing thread is weak and the dry time is long. In case where the catalyst of more than 5 wt % is mixed, the padding process for the coating liquid is difficult because of the evaporation of moisture and the efficiency of the sewing thread may be low because of high strength. Accordingly, the catalyst of 1 to 5 wt % preferably is mixed.

In accordance with a preferred embodiment of the present invention, the catalyst is formed by mixing aliphatic isophthalic diisocyanate and ethyl acetate in order to control strength. Catalyst components, composed of aliphatic isophthalic diisocyanate of 75%, ethyl acetate of 15%, and other additives of 10%, can preferably be used.

In general, in the coating liquid formation process, a mixture is agitated because albamide (that is, a chip state) has to be heated while the albamide is dissolved using using a solvent. However, the coating liquid according to the present invention is a water based material, which does not require an additional heating process. Accordingly, the process is convenient and the time taken to perform the process is reduced.

In the padding process, the sewing thread is coated by dipping the sewing thread in the mixed coating liquid. This process is performed to make uniform the bonding of the sewing thread. A bonding pickup ratio may be in the range of 80 to 100% depending on the thickness of a raw thread.

In the padding process, the coating is performed by dipping the coating liquid in a padding vessel and soaking the sewing thread. Here, the coating liquid does not become hard at normal temperature because it is a water based material. Accordingly, the process can be rapidly performed because an additional heating process is not required.

In the dry process, the coated sewing thread is dried in a temperature range of 120 to 180° C. for 20 to 60 seconds. In a process of the coated sewing thread passing through a heat chamber, the coated sewing thread is fully dried.

In case where the dry temperature is less than 120° C. or the dry time is less than 20 seconds, the dry of the coated sewing thread is not properly performed. In this case, there is a possibility that the coating liquid may be peeled off. In case where the dry temperature is more than 180° C. or the dry time is less than 60 seconds, the coating liquid and the sewing thread may be thermally transformed and energy can be lost. Accordingly, it is preferred that the coated sewing thread be dried in a temperature range of 120 to 180° C. for 20 to 60 seconds.

In the curing process, the dried sewing thread is thermally processed in a temperature range of 150 to 200° C. for 20 to 40 seconds in order to increase elongation and harden the sewing thread. In particular, the curing process must be performed when the sewing thread is processed by using water repellents. In this case, the sewing thread is thermally processed in a sealed heat chamber in a temperature range of 150 to 200° C. for 20 to 40 seconds so that the dried coating liquid and the sewing thread can be integrally sticked.

In case where the processing temperature is less than 150° C. or the processing time is less than 20 seconds, the thermal processing purpose for increasing elongation and hardening the sewing thread cannot be achieved. In case where the processing temperature is more than 200° C. or the processing time is more than 40 seconds, the coating liquid and the sewing thread may be thermally transformed, and energy can be lost. Accordingly, it is preferred that the thermal processing be performed in a temperature range of 150 to 200° C. for 20 to 40 seconds.

In the elongation process, the cured sewing thread is elongated in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%. The elongated sewing thread is subjected to the winding process, packed, and finally completed as a product.

The elongation process can be performed by using a common method. In this method, in order to achieve elongation of 30 to 60%, the sewing thread is elongated and processed in a temperature range of 150 to 200° C. for 15 to 20 seconds which are similar to those of the curing process performed in order to increase elongation.

For reference, the elongation process is a process of reducing the linear density by lengthily extending a bundle of threads in a spinning process. Through the process, the orientation of polymer within a fiber is improved, and tensile strength and elasticity of the fiber are increased.

In accordance with a preferred embodiment of the present invention, the coating liquid can further comprise water repellent liquid in which water repellents of 3 to 8 wt % are mixed with water based bond of 46 to 51 wt % and water of 46 to 51 wt %.

If the water repellent liquid is added to the coating liquid, the water repellent liquid penetrates the sewing thread, thus preventing moisture or a change of the dimensions.

Accordingly, an anti-working ability (that is, an ability to resist the penetration of water or moisture) can be increased.

The water based bond of 46 to 51 wt % is mixed. Adhesive strength must be given to the water based bond so that the water repellents firmly stick to the sewing thread. Water is used to control viscosity and thus solve the difficulty of a task. It is preferred that a ratio of the water based bond versus water be 1:1. Fluorinated water repellents are used as the water repellents. It is preferred that the water repellents of 3 to 8 wt % be mixed so that the water repellents are uniformly mixed with the coating liquid and a desired water repellent function can be properly performed.

Furthermore, the bond sewing thread of the present invention is manufactured by coating the sewing thread by dipping the sewing thread in coating liquid, produced by mixing catalyst of 1 to 5 wt % and a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt % (where, wt % is not a known art), from among known polyester materials, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed; drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds; curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and winding the elongated sewing thread.

For reference, the sewing thread is strong, and it has a uniform thickness and a smooth and flat surface. The sewing thread is differently used according to the characteristics and thickness of fabric. In general, two-ply thread is used for hand sewing thread, and three-ply thread or six-ply thread are used for machine sewing thread.

Regarding the thickness of thread, {circle around (1)} the thickness of thread is indicated by the thread count and denier, and there are two-ply thread and three-ply thread according to the number of twisted strands. {circle around (2)} Cotton, wool, and spinning threads are indicated by the thread count ('s), and silk and synthetic fibers are indicated by denier (d). {circle around (3)} The thread count is a fixed weight system indicating thread fineness. When cotton thread of 1 pound in weight is 840 yd in length, it is called as the thread count 1 (1's), and a higher thread count is a finer thread. Denier is a fixed length system indicating thread fineness. When thread of 9,000 m in length is 1 g in weight, it is called as 1 denier (1 d), and a higher denier is a thicker thread. {circle around (4)} The number of twisted strands is indicated by writing the thickness of 1 strand, drawing ′/′, and then writing the number of twisted strands. In this case, for example, ‘75 d/3’ indicates that 3 plies each being 75 d thread are put together and actually has the thickness of 225 d. Three-ply thread is chiefly used for sewing thread. If the number of strands is not indicated, it is considered as three plies.

Furthermore, regarding the types of threads, {circle around (1)} in the case of cotton thread, twisted thread (that is, mercerized cotton) is commonly strong and lustrous and used as sewing thread. Accordingly, the twisted threads are classified into the yard counts 30(30′s/3 and 60′s/2/3), 40(40′s/3 and 80′s/2/3), 50(50′s/3 and 30′s/2), 60(60′s/3 and 40′s/2), 80(80′s/3 and 50′s/2), 100s(100′s/3), and so on. The yard counts 30 to 50 are used for thick threads and cotton and hemp cloths, and the yard counts 60 to 80 are used for thin fabrics. {circle around (2)} Silk threads are suitable for needlework of wool, silk, and mixed spinning fabrics, 21 d/4×3 threads are chiefly used, which is 252 d in thickness with the dimension of 21×4×3. {circle around (3)} Polyester is suitable for needlework of synthetic fiber fabrics or synthetic fibers blended fabrics. 75 d/3 threads are chiefly used. {circle around (4)} Thick and lustrous threads of 100 d/3 or higher are used for button holes or top stitches. There are rayon thread, polyester thread, and silk thread. {circle around (5)} T/C threads are mixed threads with 65% of polyester and 35% of cotton and suitable for needlework of synthetic fiber fabrics, cotton fabrics, and T/C blended fabrics. {circle around (6)} Hemp threads are chiefly used for sealing threads of shoemaking.

The coating liquid is produced by mixing catalyst of 1 to 5 wt % and a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt % (where, wt % is not a known art), from among known polyester materials, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)) (where, wt % is not a known art), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed; drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds; curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and winding the elongated sewing thread.

A main material for the coating liquid is polyester. In order to increase an adhesive property, aliphatic isophthalic diisocyanate (that is, a non-yellow characteristic cross-linking agent) of 7 to 11 wt % is added.

In case where aliphatic isocyanate of less than 7 wt % is mixed, the adhesive strength of the coating liquid is low. In case where aliphatic isocyanate of more than 11 wt % is mixed, the viscosity of the coating liquid is high and so workability is low. Accordingly, aliphatic isocyanate of 7 to 11 wt % preferably is mixed.

In order to make the coating liquid water-based, polyester sulfur oxide diol (that is, a water based monomer material) of 1 to 5 wt % having an MW of 400 to 500 and viscosity of 500 to 1000 CPS/25° C. (Brookfield viscometer) (where, wt % is not a known art) is adeed. Further, water of 49 to 53 wt % is added as a diluent for controlling viscosity.

The reason why water is added is that water serves as a diluent and the padding process may not be properly performed because the main material has a high viscosity.

In case where water of less than 49 wt % is mixed, viscosity is high and so workability is difficult. In case where water of more than 53 wt % is mixed, there is a possiblity that the adhesive strength of the coating liquid may be low. Accordingly, water of 49 to 53 wt % preferably is added.

The catalyst of 1 to 5 wt % is added, preferably 2 wt %. The catalyst functions to rapidly dry the coating liquid padded to the bond sewing thread and to control the strength of the bond sewing thread. The amount of the catalyst mixed can be various according to circumstances. In case where the catalyst of less than 1 wt % is mixed, the strength of the bond sewing thread is weak and the dry time is long. In case where the catalyst of more than 5 wt % is mixed, the padding process for the coating liquid is difficult because of the evaporation of moisture and the efficiency of the sewing thread may be low because of high strength. Accordingly, the catalyst of 1 to 5 wt % preferably is mixed.

In accordance with a preferred embodiment of the present invention, the catalyst is formed by mixing aliphatic isophthalic diisocyanate and ethyl acetate in order to control strength. Catalyst components, composed of aliphatic isophthalic diisocyanate of 75%, ethyl acetate of 15%, and other additives of 10%, can preferably be used.

The sewing thread is coated by dipping it in the coating liquid. This process is performed to make uniform the bonding of the sewing thread. A bonding pickup ratio may be in the range of 80 to 100% depending on the thickness of a raw thread.

In the padding process, the coating is performed by dipping the coating liquid in a padding vessel and soaking the sewing thread. Here, the coating liquid does not become hard at normal temperature because it is a water based material. Accordingly, the process can be rapidly performed because an additional heating process is not required.

The coated sewing thread is dried in a temperature range of 120 to 180° C. for 20 to 60 seconds. In a process of the coated sewing thread passing through a heat chamber, the coated sewing thread is fully dried.

In case where the dry temperature is less than 120° C. or the dry time is less than 20 seconds, the dry of the coated sewing thread is not properly performed. In this case, there is a possibility that the coating liquid may be peeled off. In case where the dry temperature is more than 180° C. or the dry time is less than 60 seconds, the coating liquid and the sewing thread may be thermally transformed and energy can be lost. Accordingly, it is preferred that the coated sewing thread be dried in a temperature range of 120 to 180° C. for 20 to 60 seconds.

The dried sewing thread is thermally processed in a temperature range of 150 to 200° C. for 20 to 40 seconds in order to increase elongation and harden the sewing thread. In particular, the curing process must be performed when the sewing thread is processed by using water repellents. In this case, the sewing thread is thermally processed in a sealed heat chamber in a temperature range of 150 to 200° C. for 20 to 40 seconds so that the dried coating liquid and the sewing thread can be integrally sticked.

In case where the processing temperature is less than 150° C. or the processing time is less than 20 seconds, the thermal processing purpose for increasing elongation and hardening the sewing thread cannot be achieved. In case where the processing temperature is more than 200° C. or the processing time is more than 40 seconds, the coating liquid and the sewing thread may be thermally transformed, and energy can be lost. Accordingly, it is preferred that the thermal processing be performed in a temperature range of 150 to 200° C. for 20 to 40 seconds.

The cured sewing thread is elongated in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%. The elongated sewing thread is subjected to the winding process, packed, and finally completed as a product.

The elongation process can be performed by using a common method. In this method, in order to achieve elongation of 30 to 60%, the sewing thread is elongated and processed in a temperature range of 150 to 200° C. for 15 to 20 seconds which are similar to those of the curing process performed in order to increase elongation.

For reference, the elongation process is a process of reducing the linear density by lengthily extending a bundle of threads in a spinning process. Through the process, the orientation of polymer within a fiber is improved, and tensile strength and elasticity of the fiber are increased.

In accordance with a preferred embodiment of the present invention, the coating liquid can further comprise water repellent liquid in which water repellents of 3 to 8 wt % are mixed with water based bond of 46 to 51 wt % and water of 46 to 51 wt %.

If the water repellent liquid is added to the coating liquid, the water repellent liquid penetrates the sewing thread, thus preventing moisture or a change of the dimensions.

Accordingly, an anti-working ability (that is, an ability to resist the penetration of water or moisture) can be increased.

The water based bond of 46 to 51 wt % is mixed. Adhesive strength must be given to the water based bond so that the water repellents firmly stick to the sewing thread. Water is used to control viscosity and thus solve the difficulty of a task. It is preferred that a ratio of the water based bond versus water be 1:1. Fluorinated water repellents are used as the water repellents. It is preferred that the water repellents of 3 to 8 wt % be mixed so that the water repellents are uniformly mixed with the coating liquid and a desired water repellent function can be properly performed.

In accordance with water based bond sewing thread and the method of manufacturing the same according to the present invention, there are advantages in that flexibility is excellent, durability and strength are high and freely controlled, a risk of fading and a change of color is remarkably decreased and color reproducibility and a feeling of use are excellent even for a long time use, the manufacturing cost is low, and a supplied price is economical.

Furthermore, there are advantages in that working environments can be improved and a risk of a fire is low because a water based coating method not generating any toxic gases is used, additional process is not used in case where waterproof thread is manufactured by using water based bond sewing thread, and water treatment can be easily performed because some waterproof liquid can be mixed in a process of coating the sewing thread.

Further, in the above description, the above three products; polyester polyol, aliphatic isophthalic diisocyanate having a molecular weight (MW) of 222.2 and viscosity of 500 to 1000 CPS/25° C. (Brookfield viscometer), and polyester sulfur oxide diol (that is, a water based monomer material) having an MW of 400 to 500 and viscosity of 500 to 1000 CPS/25° C. (Brookfield viscometer) (produced by Hanyoung Industry Co., Ltd., Korea) are known in the art and widely used.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.

Claims

1. A method of manufacturing a bonded sewing thread, comprising the steps of:

forming a mixed coating liquid by adding catalyst of 1 to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed;

coating the sewing thread by dipping the sewing thread in the mixed coating liquid;

drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds;

curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds;

elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and

winding the elongated sewing thread.

2. The method according to claim 1, wherein the catalyst is formed by mixing aliphatic isophthalic diisocyanate and ethyl acetate and used to control strength.

3. The method according to claim 1, wherein the coating liquid further comprises water repellent liquid in which water based bond of 46 to 51 wt %, water of 46 to 51 wt %, and water repellents of 3 to 8 wt % are mixed.

4. A bonded sewing thread manufactured by coating the sewing thread by dipping the sewing thread in coating liquid, produced by mixing catalyst of 1 to 5 wt % and a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % are uniformly mixed; drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds; curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and winding the elongated sewing thread.

5. The bond sewing thread according to claim 4, wherein the catalyst is formed by mixing aliphatic isophthalic diisocyanate and ethyl acetate and used to control strength.

6. The bond sewing thread according to claim 4, wherein the coating liquid further comprises water repellent liquid in which water based bond of 46 to 51 wt %, water of 46 to 51 wt %, and water repellents of 3 to 8 wt % are mixed.

7. The method according to claim 2, wherein the coating liquid further comprises water repellent liquid in which water based bond of 46 to 51 wt %, water of 46 to 51 wt %, and water repellents of 3 to 8 wt % are mixed.

8. The bond sewing thread according to claim 5, wherein the coating liquid further comprises water repellent liquid in which water based bond of 46 to 51 wt %, water of 46 to 51 wt %, and water repellents of 3 to 8 wt % are mixed.