WO2008105616A1

WO2008105616A1 - Nylon yarn, two-way knitted farbric comprising the nylon yarn and method of manufacturing thereof

Info

Publication number: WO2008105616A1
Application number: PCT/KR2008/001099
Authority: WO
Inventors: Sang-Hyun Moon; Hyun-Jung Park
Original assignee: Kolon Fashion Material, Inc.
Priority date: 2007-02-26
Filing date: 2008-02-26
Publication date: 2008-09-04

Abstract

Disclosed are nylon yarn, two-way knitted fabric comprising the nylon yarn and processes for production of the same. The nylon yarn and the two-way knitted fabric according to the present invention are characterized in that a heat resistance enhancer having at least one selected from amide group, amino group and phosphorous (P) atom in molecular chains thereof is applied to surfaces of the nylon yarn and the knitted fabric, respectively. The nylon yarn of the present invention which is combined with knitting yarns such as spandex yarn, is useful for yarns for two-way knitted fabrics with excellent shrinkage in two directions. In addition, the two-way knitted fabric of the present invention can overcome problems of poor dyeing effect such as un- dyeing or generation of longitudinal lines on the fabric, which often occurs due to insufficient heat resistance.

Description

NYLON YARN, TWO-WAY KNITTED FABRIC COMPRISING THE NYLON YARN AND METHOD OF MANUFACTURING THEREOF

TECHNICAL FIELD r> The present invention relates to nylon yarn with excellent heat resistance, two-way knitted fabric comprising the nylon yarn, and a method for manufacturing the same, and more particularly, to nylon yarn with improved heat resistance and dyeing properties by coating surface of the yarn with heat resistance enhancer, two-way knitted

10 fabric comprising the yarn, and a method for manufacturing the same.

Nylon yarn has been used in manufacturing woven fabrics and/ or knitted fabrics and, in recent days, the nylon yarn is commonly used in manufacturing specific knitted fabrics with excellent flexibility (or shrinkage) in both directions (hereinafter, referred to as "two-way

Ib knitted fabric"). Such two-way knitted fabric is formed by knitting a spandex yarn with a nylon yarn to endow superior shrinkage in two directions, and is mostly applied to production of yarns for swimming suits, underwear for women, etc.

Hereinafter, a two-way knitted fabric of the present invention

20 means a knitted fabric with excellent shrinkage in two directions by knitting together a spandex yarn and a nylon yarn, and the knitted fabric is effectively used in manufacturing swimming suits, underwear for women and the like. BACKGROUND ART

AvS shown in Fig. 1, a two-way knitted fabric must undergo presetting and final setting processes at 190 to 200 °C for heat fixing the fabric before or after a dyeing process, so as to fix shrinkage of a spandex yarn for preparing the two-way knitted fabric.

Such heat fixing processes have problems in that the nylon yarn vulnerable or susceptible to the heat sustains modification and /or alteration of physical properties and/ or original characteristics at the heat fixing temperature, thereby causing un-dyeing or generation of longitudinal lines during the dyeing process.

The un-dyeing and longitudinal line generating problems closely correlate to heat resistance and dyeing properties of the nylon yarn. In order to increase production rate of yarns during a dyeing process in manufacturing two-way knitted fabrics, a heat fixing temperature tends to be set up higher, which is, in turn, expected to more seriously cause the above problems in the future.

In order to overcome such problems, there have been many attempts to improve heat resistance of a nylon yarn by adding a variety of heat resistance enhancers during polymerization in production of nylon polymer, which is further used in manufacturing two -way knitted fabrics. However, conventional methods have a disadvantage of requiring the heat resistance enhancer in great quantities in order to accomplish desired improvement of heat resistance since the heat resistance enhancer is homogeneously dispersed over entire cross- sectional area of the yarn. As a result, the above known methods demand considerable production costs of the nylon yarn, leading to limited uses for commercially available applications.

An alternative method known in prior art is to improve heat resistance of nylon yarn for two-way knitted fabric by treating surface of the yarn with a spinning emulsion containing a heat resistance enhancer while spinning the nylon yarn. However, since the spinning emulsion which was coated on the yarn surface is not homogeneously released during a relaxing process as one of working processes for treatment of fabric bases, the method expresses insufficient heat resistance during a following pre-setting process so as to cause a problem of irregular dyeing effects such as generation of longitudinal lines.

DISCLOSURE OF THE INVENTION

(TECHNICAL PROBLEM)

Accordingly, the present invention is directed to solve the problems described above in regard to conventional methods and an object of the present invention is to improve heat resistance and dyeing properties of a nylon yarn with low production cost.

Another object of the present invention is to provide a two-way knitted fabric which continuously exhibits superior heat resistance and dyeing properties during working processes for knitted fabric without defects such as irregular dyeing effect including longitudinal lines.

In order to accomplish the above objects, the present invention provides a method for coating surface of a nylon yarn with a coating solution containing a specific heat resistance enhancer dissolved in water or a nylon spinning emulsion, so as to improve heat resistance and dyeing properties of the nylon yarn with low production cost.

The present invention also provides a nylon yarn with excellent strength retention rate and elongation retention rate after heat treatment by preparing the nylon yarn coated with the heat resistance enhancer according to the above method.

The present invention also provides a padding method of a basic textile (hereinafter, referred to as "fabric base") for two-way knitted fabric by treating the fabric base with a padding solution containing a specific heat resistance enhancer in water immediately before pre-heat fixing (or pre-setting) the fabric base, which already underwent a relaxing process, so as to continuously express excellent heat resistance during working processes and inhibit un-dyeing and/or generation of longitudinal lines.

The present invention also provides a two-way knitted fabric having excellent heat resistance and dyeing properties without irregular dyeing effect such as generation of longitudinal lines and/ or un-dyeing obtained by the above method, which has yellow index ranging from 1 to 20 to indicate heat resistance, and K/ S value ranging from 5.2 to 6.1 to indicate dyeing properties.

(TECHNICAL MEANS TO SOLVE THE PROBLEM)

The present invention will be particularly described below. A nylon yarn according to the present invention is characterized in that surface of the yarn is coated with a heat resistance enhancer having at least one selected from amide group, amino group and phosphorous atom in molecular chains.

Examples of such heat resistance enhancer include a compound having amide group and benzene ring in molecular chains, anion surfactant having phosphorus (P) atom in molecular chains, amphoteric surfactant having amino group in molecular chains, etc. The compound having amide group and benzene ring in molecular chains includes, for example, 1,3-benzenedicarboxamide- N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) represented by the following formula I:

(I)

A method for manufacturing a nylon yarn with excellent heat resistance according to the present, invention comprises: preparing a coating solution by dissolving a heat resistance enhancer, which has at least one selected from amide group, amino group and phosphorus (P) atom in molecular chains, in water or a spinning emulsion for nylon yarn; and applying the coating solution to surface of the nylon yarn.

The heat resistance enhancer is preferably exemplified by a compound having amide group and benzene ring in molecular chains, anion surfactant having phosphorus (P) atom in molecular chains, amphoteric surfactant having amino group in molecular chains and the like.

The compound having amide group and benzene ring in molecular chains includes, for example, 1,3-benzenedicarboxamide- N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) represented by the following formula I:

A content of the heat resistance enhancer contained in the coating solution preferably ranges from 0.05 to 5% by weight.

If the content is below 0.05% by weight, improvements of heat resistance and dyeing properties are substantially so little to cause generation of longitudinal lines and /or un-dyeing effect during production of the two-way knitted fabric. Conversely, with the content of more than 5% by weight, the coating solution has increased viscosity 5 to cause a difficulty in coating surface of the nylon yarn with the coating solution.

The method for coating surface of a nylon yarn with a coating solution includes, for example: (i) applying a coating solution to surface of a nylon yarn while spinning the nylon yarn by feeding the coating

K) solution to a spinning emulsion supply roller during a spinning process of the nylon yarn; (ii) dipping a nylon yarn in a coating solution during a spinning process or after a reeling process of the nylon yarn; and (iii) spraying a coating solution over surface of a nylon yarn during a spinning process or after a reeling process of the nylon yarn, etc. i n The spinning emulsion for nylon yarn used in the present invention is not particularly limited and generally includes any one of spinning emulsions commonly available for reeling the nylon yarn.

Preferred examples of the heat resistance enhancer include: KMN-2011™ available from Matsumoto Yushi-Seiyaku Co., Ltd., Japan, 0 which is an anion surfactant having phosphorus (P) atom in molecular chains; KIN 436™ available from Takemoto Oil & Fat Co., Ltd., Japan, which is an amphoteric surfactant having amino group in molecular chains; and l,3-benzenedicarboxamide-N,N'-bis (2,2,6,6-tetramethyl~4- piperidyl) represented by the above formula I, etc.

The heat resistance enhancer represented by the above formula I includes a compound having amide group and benzene ring in molecular chains. The amide group increases hydrogen bonds between it and a nylon chain to improve tensile strength and elongation of the yarn, while an amino terminal group increases dyeing ability of the enhancer to improve dyeing properties of acidic dyes.

Furthermore, the benzene ring can improve thermal stability of the nylon yarn. The anion surfactant and the amphoteric surfactant have phosphorus (P) atom and amino group in molecular chains, l'espectively, to increase hydrogen bonds between phosphorus (P) atom or amino group and nylon chain thereby improving tensile strength and/ or heat resistance of the nylon yarn. The coating solution used in the present invention is prepared by dissolving l,3-benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4- piperidyl) represented by the above formula I in a spinning emulsion for nylon yarn, or each of the anion surfactant and the amphoteric surfactant in water. Since the heat resistance enhancer is applied only to surface of the nylon yarn, the present invention can accomplish improvement of heat resistance and/ or dyeing properties substantially equal to that achieved by a known process comprising addition of the above compound (represented by the formula I) to nylon polymer during polymerization thereof, even when a small amount of the compound is added to the enhancer. As a result, the present invention can considerably reduce the production cost. The inventive method has additional advantages in that this is easily applicable and selectively applicable to nylon yarns requiring improved heat resistance among those produced from the same spinning dope.

The nylon yarn produced by the present inventive method, surface of which was coated with the heat resistance enhancer described above, represents strength reteniion rate ranging from 70 to 85% and elongation retention rate ranging from 70 to 100% after heat treatment at 190°C for 10 minutes.

If the strength retention rate after heat treatment is less than the lower limit, it is liable to generate longitudinal lines or un -dyeing effect on a fabric during hot setting (at 190^°C or more) in a post- working process of the fabric. When the strength retention rate after heat treatment exceeds the upper limit, the coating solution has poor stability by increasing an amount of the heat resistance enhancer to cause irregular application of the coating solution to surface of the nylon yarn, so that the nylon yarn has irregularities in original characteristics.

If the elongation retention rate after heat treatment is less than the lower limit, it is also liable to generate longitudinal lines or un- dyeing effect on a fabric at high temperature and under high tension force in a post-working process of the fabric. On the other hand, the coating solution is irregularly applied to surface of the nylon yarn when the elongation retention rate after heat treatment exceeds the upper limit, so lhat the nylon yarn has increased irregularities in original characteristics.

The two-way knitted fabric according to the present invention comprises nylon yarns and spandex yarns, is coated with a specific heat resistance enhancer having at least one selected from amide group, amino group and phosphorus (P) atom in molecular chains on surface of the fabric, and has yellow index ranging from 1 to 20 when the fabric is heat treated at 190 °C for 10 minutes.

The above heat resistance enhancer includes, for example, a compound having amide group and benzene ring in molecular chains, anion surfactant having phosphorus (P) atom in molecular chains, amphoteric surfactant having amino group in molecular chains and the like.

The compound having amide group and benzene ring in molecular chains as the heat resistance enhancer includes 1 ,3- benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) represented by the following formula I:

A method for manufacturing a two-way knitted fabric according to the present invention comprises a padding treatment of a fabric, after relax processing to remove spinning emulsion moiety adhered to a

!) fabric base and immediately before pre- setting the fabric, otherwise, a padding treatment of a dyed fabric immediately before final- setting the fabric, by using a padding solution containing a heat resistance enhancer that has at least one selected from amide group, amino group and phosphorus (P) atom in molecular chains thereof, in water or a0 spinning emulsion for nylon yarn.

The heat resistance enhancer is preferably exemplified by a compound having amide group and benzene ring in molecular chains, anion surfactant having phosphorus (P) atom in molecular chains, amphoteric surfactant having amino group in molecular chains and the r> like.

The compound having amide group and benzene ring in molecular chains as the heat resistance enhancer includes 1,3- benzenedicarboxamide-N,N'-bis(2,2,6,6 -tetramethyl-4-piperidyl) represented by the following formula I:

Conventionally, a method for processing a two-way knitted fabric base is shown in Fig. 1, which includes the steps of: (i) relax processing the fabric base by dipping the fabric base in warm water to remove spinning emulsion moiety adhered on surface of the base; (ii) pre-setting the treated base at 190 to 200 °C ; (iii) dyeing the pre-set base; and (iv) final- setting the dyed base at 190 to 200 °C in order.

Fig. 1 is a flow chart illustrating an example of the present inventive method for manufacturing a two-way knitted fabric. The fabric base contains about 1.8% by weight of spinning emulsion moiety to total weight of the base and about half of the moiety is irregularly eliminated by the relax processing.

Accordingly, in case that the spinning emulsion containing the heat resistance enhancer is applied to surface of the nylon yarn while spinning the nylon yarn as described in the above conventional method in order to improve heat resistance and dyeing properties of a nylon yarn for the two-way knitted fabric, the spinning emulsion moiety adhered on the yarn surface is irregularly removed during the relax processing as one of several working processes for the fabric, leading to poor expression of heat resistance in following processes such as presetting, dyeing and final-setting processes, so that this causes problems of irregular dyeing effect such as un -dyeing and/ or generation of longitudinal lines. In order overcome the above problems, the present invention provides a method for manufacturing a two-way knitted fabric which comprises a padding treatment of a fabric base by treating the fabric base with a padding solution containing a heat resistance enhancer in water or a spinning emulsion for nylon yarn, after relax processing and immediately before pre-setting the fabric base, so as to continuously express desired heat resistance during following processes including pre-setting, dyeing and final-setting processes. As a result, the present inventive method can eliminate irregular dyeing problems such as un- dyeing and/or generation of longitudinal lines in the fabric. The relax processing is a process for removing emulsion moiety and impurities included in the fabric base and simply fixing shrinkage of the fabric base with water by dipping the fabric base in water.

More particularly, the above processing is performed by passing the fabric base through five or six baths in stages at a speed of 25 to 30m/ min for 60 to 90 seconds.

First bath contains water at about 85 ^°C and the water temperature of the bath is gradually decreased toward sixth bath, thus, the water in the final (sixth) bath is preferably maintained at room temperature.

The pre-setting process uses a tenter to thermally fix the fabric base, and is preferably performed at 180 to 195⁰C and at a bath passing speed of about 30m/ min.

S The dyeing process uses a rapid dyeing machine according to typical dyeing procedures and under general conditions.

The final-setting process is performed by the substantially same manner for the pre-setting process and, may further use additional softeners or absorbents for the fabric depending on uses thereof.

IU In order to overcome the above problems, the present invention also provides a method for manufacturing a two-way knitted fabric which comprises a padding treatment of a fabric base by treating the fabric base with a padding solution containing a heat resistance enhancer in water or a spinning emulsion for nylon yarn, after relax

15 processing and dyeing and immediately before final-setting the fabric base, so as to continuously express desired heat resistance during the following final-setting process. As a result, the present inventive method can eliminate irregular dyeing problems such as un- dyeing and/ or generation of longitudinal lines in the fabric. 0 Treatment conditions such as bath passing speed, temperature, etc. together with treatment procedures for the above working processes are not particularly limited in the present invention.

Content of the heat resistance enhancer dissolved in the padding solution preferably ranges from 0.05 to 5% by weight.

If the content is below 0.05% by weight, improvements of heat resistance and dyeing properties are substantially so little to cause generation of longitudinal lines and/ or un-dyeing effect duringi production of the two-way knitted fabric. Conversely, with the content of more than 5% by weight, the padding solution has increased viscosity to cause a difficulty in padding the solution on surface of the fabric base.

The padding process includes two steps of dipping the fabric) base in the padding solution and squeezing, that is, pressing out the wetted fabric base by a squeezing roller.

Preferred examples of the heat resistance enhancer include: KMN-2011™ available from Matsumoto Yushi-Seiyaku Co., Ltd., Japan, which is an anion surfactant having phosphorus (P) atom in molecular > chains; KIN 436™ available from Takemoto Oil 85 Fat Co., Ltd., Japan, which is an amphoteric surfactant having amino group in molecular chains; and l ,3-benzenedicarboxamide-N,N'-bis (2,2,6,6-tetramethyl-4- piperidyl) represented by the above formula I, etc.

The coating solution used in the present invention is prepared by dissolving 1 ,3-benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4- piperidyl) represented by the above formula I in a spinning emulsion for nylon yarn, or each of the anion surfactant and the amphoteric surfactant in water.

Ll The two-way knitted fabric produced by the above method according to the present invention comprises nylon yarns and spandex yarns, is coated with a padding solution containing a specific heat resistance enhancer on surface of the fabric, and has yellow index r> ranging from 1 to 20 and K/ S value (color value) ranging from 5.2 to 6.1 when the fabric is heat treated at 190 ^°C for 10 minutes.

If yellow index is not within the above defined range, the fabric has low heat resistance to easily cause irregular dyeing effect. On the other hand, with K/ S value out of the above defined range, the fabric K) has poor or deteriorated appearance.

In the present invention, the yellow index and K/ S value were determined by means of Computer Color Matching process. (ADVANTAGEOUS EFFECTS)

The present invention can improve heat resistance and dyeing

15 properties of nylon yarns with relatively low production cost, and especially can be easily applied to various species of yarns requiring favorable heat resistance and dyeing properties. Therefore, the nylon yarn prepared according to the present invention is particularly useful for knitting yarns including yarns for two-way knitted fabrics. 0 A method for manufacturing a two-way knitted fabric according to the present invention comprises a padding treatment of a fabric after relax processing and immediately before pre-setting the fabric, otherwise, a padding treatment of a dyed fabric immediately before

I H final- setting the fabric by using a padding solution containing a heat resistant material, so as to produce the fabric with considerably improved heat resistance and dyeing properties. Accordingly, the present inventive method can eliminate problems of poor dyeing effect such as un-dyeing or generation of longitudinal lines on the fabric, which often occurs due to insufficient heat resistance during the fabric production.

Because of excellent heat resistance, the present invention can setup temperature for heat treatment to high level to shorten time for the heat treatment, thereby advantageously improving productivity of the fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects, features and advantages of the present. invention will become more apparent to those skilled in the related art in conjunction with the accompanying drawing. In the drawing:

Fig. 1 is a flow chart illustrating an example of a process for production of a two-way knitted fabric according to the present invention .

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail from the following examples and comparative examples with reference to the accompanying drawing. However, these are intended to illustrate the invention as preferred embodiments of the present invention and do not limit the scope of the present invention.

EXAMPLE 1 .1 Firstly, a coating solution was prepared by dissolving 0.2% by weight ("wt.%") of KMN- 201 1™ available from Matsumoto Yushi-

Seiyaku Co., Ltd., Japan, which is an anion surfactant having phosphorus (P) atom in molecular chains as a heat resistance enhancer, in water. 10 Next, a nylon yarn comprising 1 3 filaments with 45 denier was prepared by coating surface of the yarn driving on a spinning emulsion supply roller with the prepared coating solution instead of the spinning emulsion during a spinning process for nylon yarn.

Lastly, using the prepared nylon yarn as well as a spandex yarn Ib comprising 3 filaments with 40 denier in a ratio by weight of 85wt.% to

15wt.%, a two-way knitted fabric was produced as the final product.

Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric 0 product, are shown in Table 1.

EXAMPLE 2

Firstly, a coating solution was prepared by dissolving 1.2wt.% of

KMN-201 1™ available from Matsumoto Yushi-Seiyaku Co., Ltd., Japan, which is an anion surfactant having phosphorus (P) atom in molecular chains as a heat resistance enhancer, in water.

Next, a nylon yarn comprising 13 filaments with 45 denier was prepared by coating surface of the yarn driving on a spinning emulsion supply roller with the prepared coating solution instead of the spinning emulsion during a spinning process for nylon yarn.

Lastly, using the prepared nylon yarn as well as a spandex yarn comprising 3 filaments with 40 denier in a ratio by weight of 85wt.% to 15wt.%, a two-way knitted fabric was produced as the final product. Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric product, are shown in Table 1. EXAMPLE 3 Firstly, a coating solution was prepared by dissolving 3.3wt.% of

KMN-2011™ available from Matsumoto Yushi-Seiyaku Co., Ltd., Japan, which is an anion surfactant having phosphorus (P) atom in molecular chains as a heat resistance enhancer, in water.

Lastly, using the prepared nylon yarn as well as a spandex yarn comprising 3 filaments with 40 denier in a ratio by weight of 85wt.% to 15wt.%, a two-way knitted fabric was produced as the final product.

Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in F) addition, evaluation of dyeing properties of the two-way knitted fabric product, are shown in Table 1. EXAMPLE 4

Firstly, a coating solution was prepared by dissolving 0.2wt.% of KIN 436™ available from Takemoto Oil & P"at Co., Ltd., Japan, which is KJ an amphoteric surfactant having amino group in molecular chains as a heal resistance enhancer, in water.

Next, a nylon yarn comprising 13 filaments with 45 denier was prepared by coating surface of the yarn driving on a spinning emulsion supply roller with the prepared coating solution instead of the spinning ] b emulsion during a spinning process for nylon yarn.

Results of determination of strength retention rate and 20 elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric product, are shown in Table 1. EXAMPLE 5 Firstly, a coating solution was prepared by dissolving 1.0wt.% of KIN 436™ available from Takemoto Oil 8B Fat Co., Ltd., Japan, which is an amphoteric surfactant having amino group in molecular chains as a heat resistance enhancer, in water.

,) Next, a nylon yarn comprising 13 filaments with 45 denier was prepared by coating surface of the yarn driving on a spinning emulsion supply roller with the prepared coating solution instead of the spinning emulsion during a spinning process for nylon yarn.

Lastly, using the prepared nylon yarn as well as a spandex yarn 10 comprising 3 filaments with 40 denier in a ratio by weight of 85wt.% to 15wt.%, a two-way knitted fabric was produced as the final product.

Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric lf> product, are shown in Table 1. EXAMPLE 6

Firstly, a coating solution was prepared by dissolving 3.0wt.% of KIN 436™ available from Takemoto Oil & Fat Co., Ltd., Japan, which is an amphoteric surfactant having amino group in molecular chains as a 0 heat resistance enhancer, in water.

Next, a nylon yarn comprising 13 filaments with 45 denier was prepared by coating surface of the yarn driving on a spinning emulsion supply roller with the prepared coating solution instead of the spinning

2 \ emulsion during a spinning process for nylon yarn.

Lastly, using the prepared nylon yarn as well as a spandex yarn comprising 3 filaments with 40 denier in a ratio by weight of 85wt.% to 15wt.%, a two-way knitted fabric was produced as the final product. I; Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric product, are shown in Table 1. EXAMPLE 7

H) Firstly, a coating solution was prepared by dissolving 0.2wt.% of l,3-benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) represented by the above formula I in a spinning emulsion for nylon yarn with 2% concentration.

Next, a nylon yarn comprising 13 filaments with 45 denier was 15 prepared by coating surface of the yarn driving on a spinning emulsion supply roller with the prepared coating solution instead of the spinning emulsion during a spinning process for nylon yarn.

Lastly, using the prepared nylon yarn as well as a spandex yarn comprising 3 filaments with 40 denier in a ratio by weight of 85wt.% to 20 15wt.%, a two-way knitted fabric was produced as the final product.

Results of determination of strength retention rate arid elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric product, are shown in Table 1. EXAMPLE 8

Firstly, a coating solution was prepared by dissolving 0.2wt.% of l,3-benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) represented by the above formula I in a spinning emulsion for nylon yarn with 10% concentration.

Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric product, are shown in Table 1. EXAMPLE 9

Firstly, a coating solution was prepared by dissolving 0.5wt.% of l,3-benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) represented by the above formula I in a spinning emulsion for nylon yarn with 10% concentration.

Next, a nylon yarn comprising 13 filaments with 45 denier was

2Λ^' prepared by coating surface of the yarn driving on a spinning emulsion supply roller with the prepared coating solution instead of the spinning emulsion during a spinning process for nylon yarn.

Lastly, using the prepared nylon yarn as well as a spandex yarn b comprising 3 filaments with 40 denier in a ratio by weight of 85wt.% to 15wt.%, a two-way knitted fabric was produced as the final product.

Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric K) product, are shown in Table 1. COMPARATIVE EXAMPLE 1

A nylon yarn and a two-way knitted fabric were produced by the same procedure as described in Example 1 except that a commonly available spinning emulsion for nylon yarn without a heat resistance in enhancer was used during the spinning process.

Results of determination of strength retention rate and elongation retention rate of the nylon yarn after heat treatment, and, in addition, evaluation of dyeing properties of the two-way knitted fabric product, are shown in Table 1. 0 TABLE 1

From the above Table 1, the strength retention rate and the

elongation retention rate after heat treatment are values calculated by applying strength and elongation values measured after heat treating

the nylon yarn at 190°C for 10 minutes as well as strength and

elongation values before the heat treatment to the following equation:

strength before heat treatment-strength after heat treatment

^" xlOO strength before heat treatment

p_l . . _r , _/nM elongation before heat treatment-elongation after heat treatment ...

Elongation retention rate after heat treatment(% )= - - - - — — -— - - — ^? - xlOO elongation betore heat treatment

U) Alternatively, dyeing properties of the two-way knitted fabric were evaluated by visibly observing whether there were longitudinal lines and/or un-dyed parts of a two-way knitted fabric base in an area with dimension of Im² width by Im² height after dyeing the fabric base with an acidic dye under typical dyeing conditions. •> EXAMPLE 10

Firstly, a padding solution was prepared by dissolving 2.0wt.% of KMN-2011™ available from Matsumoto Yushi-Seiyaku Co., Ltd., Japan, which is an anion surfactant having phosphorus (P) atom in molecular chains as a heat resistance enhancer, in pure water.

J O Alternatively, a fabric base comprising 80wt.% of nylon yarn and

20wt.% of spandex yarn and containing 1.5wt.% of spinning emulsion was relaxing processed by passing the fabric base through five-staged water baths containing water at 80 T , 70 ^°C , 60 ^°C , 5Of and 25 f , respectively, in steps at a speed of 25m/min for 70 seconds.

I f) Following the above, the relaxing processed fabric base was treated using the above prepared padding solution.

The padding treated fabric base was subjected to a pre-setting process while passing the base into a tenter at 280 ^°C and a speed of 30m/ min, a dyeing process using a Rapid dyeing machine by general

20 dyeing method and under general dyeing conditions, and a final-setting process under the same conditions as the pre-setting process, so as to produce a finally knitted fabric.

Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 2. EXAMPLE 11

Firstly, a padding solution was prepared by dissolving 0.2wt.% of l ,3-benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) f) represented by the above formula I in a spinning emulsion for nylon yarn with 2% concentration.

Alternatively, a fabric base comprising 80wt.% of nylon yarn and

20wt.% of spandex yarn and containing 1.5wt.% of spinning emulsion was relaxing processed by passing the fabric base through five-staged

K) water baths containing water at 80 ^"C , 70 ^°C , 60 ^°C , 50 ^°C and 25 ^°C , respectively, in steps at a speed of 25m/min for 70 seconds.

Following the above, the relaxing processed fabric base was treated using the above prepared padding solution.

The padding treated fabric base was subjected to a pre-setting 15 process while passing the base into a tenter at 280 ^°C and a speed of 30m/ min, a dyeing process using a Rapid dyeing machine by general dyeing method and under general dyeing conditions, and a final-setting process under the same conditions as the pre-setting process, so as to produce a finally knitted fabric. 0 Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 2. EXAMPLE 12

Firstly, a padding solution was prepared by dissolving 2.0wt.% of KIN 436™ available from Takemoto Oil 85 Fat Co., Ltd., Japan, which is an amphoteric surfactant having amino group in molecular chains as a heat resistance enhancer, in pure water.

Alternatively, a fabric base comprising 80wt.% of nylon yarn and

[) 20wt.% of spandex yarn and containing 1.5wt.% of spinning emulsion was relaxing processed by passing the fabric base through five-staged water baths containing water at 8Ot , 70 t , 60 ^°C , 50 ^"C and 25 ^°C , respectively, in steps at a speed of 25m /min for 70 seconds.

Following the above, the relaxing processed fabric base was U) treated using the above prepared padding solution.

The padding treated fabric base was subjected to a pre-setting process while passing the base into a tenter at 195 C and a speed of 30m/ min, a dyeing process using a Rapid dyeing machine by general dyeing method and under general dyeing conditions, and a final-setting I Jj process under the same conditions as the pre-setting process, so as to produce a finally knitted fabric.

Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 2. COMPARATIVE EXAMPLE 2

20 The fabric base which was relaxing processed as in Example 1, was directly subjected to the pre-setting process, instead of padding the fabric base with a padding solution containing a heat resistance enhancer. Then, the pre-setting processed fabric base underwent the dyeing process and the final-setting process substantially the same as in Example 1, thereby producing a finally knitted fabric.

Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 2.

TABLE 2

Firstly, a padding solution was prepared by dissolving 2.0wt.% of KMN -2011™ available from Matsumoto Yushi-Seiyaku Co., Ltd., Japan, 10 which is an anion surfactant having phosphorus (P) atom in molecular chains as a heat resistance enhancer, in pure water.

Alternatively, a fabric base comprising 80wt.% of nylon yarn and

IT) water baths containing water at 80 "C , 70 °C , 60 ^°C , 50 ^°C and 25 T , respectively, in steps at a speed of 25m/ min for 70 seconds.

The relaxing processed fabric base was subjected to a pre-settirig process while passing the base into a tenter at 195 °C and a speed of 30m/ min, and a dyeing process using a Rapid dyeing machine by general dyeing method and under general dyeing conditions.

Subsequently, the dyed fabric base was treated using the above prepared padding solution then underwent a final-setting process under the same conditions as the pre-setting process, so as to produce a finally knitted fabric.

Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 3. EXAMPLE 14

Firstly, a padding solution was prepared by dissolving 0.2wt.% of l ,3-benzenedicarboxamide-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) represented by the above formula I in a spinning emulsion for nylon yarn with 2% concentration.

Alternatively, a fabric base comprising 80wt.% of nylon yarn and

20wt.% of spandex yarn and containing 1.5wt.% of spinning emulsion was relaxing processed by passing the fabric base through five-staged water baths containing water at 80 V , 70 ^"C , 60 ^°C , 50 ^°C and 25 ^°C , respectively, in steps at a speed of 25m/min for 70 seconds.

The relaxing processed fabric base was subjected to a pre-setting process while passing the base into a tenter at 195^°C and a speed of 30m /min, and a dyeing process using a Rapid dyeing machine by general dyeing method and under general dyeing conditions.

Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 3. EXAMPLE 15

Firstly, a padding solution was prepared by dissolving 2.0wt.% of KIN 436™ available from Takemoto Oil 85 Fat Co., Ltd., Japan, which is an amphoteric surfactant having amino group in molecular chains as a heat resistance enhancer, in pure water. Alternatively, a fabric base comprising 80wt.% of nylon yarn and

20wt.% of spandex yarn and containing 1.5wt.% of spinning emulsion was relaxing processed by passing the fabric base through five- staged water baths containing water at 80 V , 7Of , 6Of , 5Of and 25 f , respectively, in steps at a speed of 25m/ min for 70 seconds. The relaxing processed fabric base was subjected to a pre-setting process while passing the base into a tenter at 280 °C and a speed of 30m/min, and a dyeing process using a Rapid dyeing machine by general dyeing method and under general dyeing conditions.

Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 3. COMPARATIVE EXAMPLE 3

The fabric base which was dyed as in Example 1 , was directly subjected to the final-setting process, instead of padding the fabric base with the padding solution as in Example 1 , thereby producing a finally knitted fabric.

Results of determination of K/ S value and yellow index of the final fabric product are shown in Table 3.

TABLE 3

K)

INDUSTRIAL APPLICABILITY

As described in detail above, the nylon yarn and the two-way knitted fabric according to the present invention are effectively useable as yarns and fabrics applied to manufacturing swimming suits, J [> underwear for women, etc.

While the present invention has been described with reference to the above preferred embodiments, it will be understood by those skilled in the art that various modifications and variations may be made therein without departing from the scope of the present invention as

S ^' 2 defined by the appended claims.

Claims

WHAT IS CLAIMED IS;

1. A nylon yarn coated with a heat resistance enhancer having at r> least one selected from amide group, amino group and phosphorus (P) atom in molecular chains thereof on surface of the nylon yarn.

2. The nylon yarn according to Claim 1 , wherein the heat resistance enhancer includes a compound having amide group and benzene ring in molecular chains. 0

3. The nylon yarn according to Claim 1, wherein the heat resistance enhancer includes anion surfactant having phosphorus (P) atom in molecular chains.

4. The nylon yarn according to Claim 1, wherein the heat resistance enhancer includes amphoteric surfactant having amino group in 5 molecular chains.

5. The nylon yarn according to Claim 2, wherein the compound having amide group and benzene ring in molecular chains as the heat resistance enhancer is l,3-benzenedicarboxamide-N,N'-bis(2,2,6,6- tetramethyl-4-piperidyl) represented by the following formula 1:

6. The nylon yarn according to Claim 1, wherein the nylon has strength retention rate ranging from 70 to 85% and elongation retention rate ranging from 70 to 100% after heat treatment at 190 "C for 10

5 minutes.

7. A method for manufacturing a nylon yarn comprising the steps of: preparing a coating solution by dissolving a heat resistance enhancer, which has at least one selected from amide group, amino K) group and phosphorus (P) atom in molecular chains thereof, in water or a spinning emulsion for nylon yarn; and coating surface of the nylon yarn with the coating solution.

8. The method according to Claim 7, wherein the heat resistance enhancer includes a compound having amide group and benzene ring in

1 r> molecular chains.

9. The method according to Claim 7, wherein the heat resistance enhancer includes anion surfactant having phosphorus (P) atom in molecular chains.

10. The method according to Claim 7, wherein the heat resistance enhancer includes amphoteric surfactant having amino group in molecular chains.

11. The method according to Claim 8, wherein the compound having amide group and benzene ring in molecular chains as the heat resistance enhancer is l ,3-benzenedicarboxamide-N,N'-bis(2,2,6,6- tetramethyl-4-piperidyl) represented by the following formula I:

12. The method according to Claim 7, wherein a content of the heat resistance enhancer ranges from 0.05 to 5% by weight.

10 13. The method according to Claim 7, wherein the coating process is performed by applying the coating solution to surface of the nylon yarn using an emulsion supply roller during a spinning process for nylon yarn, while spinning the nylon yarn.

14. The method according to Claim 7, wherein the coating process is ir> performed by dipping the nylon yarn in the coating solution in any one step selected from the spinning process and further processes following the spinning process, so as to coat surface of the nylon yarn.

15. The method according to Claim 7, wherein the coating process is performed by spraying the coating solution over the nylon yarn in εmy one step selected from the spinning process and further processes following the spinning process, so as to coat surface of the nylon yarn.

16. A two-way knitted fabric comprising nylon yarns and spandex yarns, which is coated with a heat resistance enhancer having at least

5 one selected from amide group, amino group and phosphorus (P) atom in molecular chains, on surface of the fabric and has yellow index (YI) ranging from 1 to 20 when the fabric is heat treated at 190 ^"C for 10 minutes.

17. The knitted fabric according to Claim 16, wherein the heat 10 resistance enhancer includes a compound having amide group and benzene ring in molecular chains.

18. The knitted fabric according to Claim 16, wherein the heat resistance enhancer includes anion surfactant having phosphorus (P) atom in molecular chains. in

19. The knitted fabric according to Claim 16, wherein the heat resistance enhancer includes amphoteric surfactant having amino group in molecular chains.

20. The knitted fabric according to Claim 17, wherein the compound having amide group and benzene ring in molecular chains as the heat

20 resistance enhancer is l,3-benzenedicarboxamide-N,N'-bis(2,2,6,6- tetramethyl-4-piperidyl) represented by the following formula I:

21. The knitted fabric according to Claim 16, wherein the knitted fabric has K/ S value as color value ranging from 5.2 to 6.1 when the fabric is heat treated at 190°C for 10 minutes.

F> 22. A method for manufacturing a two-way knitted fabric comprising a padding treatment of a fabric, after relax processing to remove spinning emulsion adhered to a fabric base and immediately before presetting the fabric, otherwise, a padding treatment of a dyed fabric immediately before final-setting the fabric, by using a padding solution K) containing a heat resistance enhancer that has at least one selected from amide group, amino group and phosphorus (P) atom in molecular chains thereof, in water or a spinning emulsion for nylon yarn.

23. The method according to Claim 22, wherein the heat resistance enhancer includes a compound having amide group and benzene ring in

15 molecular chains.

24. The method according to Claim 22, wherein the heat resistance enhancer includes anion surfactant having phosphorus (P) atom in molecular chains.

25. The method according to Claim 22, wherein the heat resistance enhancer includes amphoteric surfactant having amino group in molecular chains.

26. The method according to Claim 23, wherein the compound having amide group and benzene ring in molecular chains as the heat 5 resistance enhancer is l ,3-benzenedicarboxamide-N,N'-bis(2,2,6,6- tetramethyl-4-piperidyl) represented by the following formula I:

27. The method according to Claim 23, wherein a content of the heat resistance enhancer in the padding solution ranges from 0.05 to 5% by

K) weight.

28. The method according to Claim 23, wherein the knitted fabric passed the pre-setting process is subjected to a dyeing process and a final-setting process.