KR20220118687A - Thermally adhesive composite fiber with uniform fineness, Method preparing same and non-woven fiber comprising the same - Google Patents

Abstract

The present invention relates to a thermally adhesive composite fiber with a uniform fineness, a manufacturing method therefor, and non-woven fabric comprising the same. According to the present invention, a thermally adhesive composite fiber with a uniform fineness can be manufactured through composite spinning of, using a titanium-based polymerization catalyst, an inner portion including a polyester-based resin having a crystallization temperature of 130 ℃ or higher, and an outer portion including an olefin-based resin, wherein thermally adhesive composite fiber with a uniform fineness uses an appropriate amount of a titanium-based polymerization catalyst and a resin having an appropriate weight average molecular weight. Accordingly, the non-woven fabric is manufactured by using the same, not only the hydrophilicity and bulkiness of the non-woven fabric are improved, but also the non-woven fabric has a uniform thickness, is suitable for sanitary products.

Description

Thermally adhesive composite fiber with uniform fineness, manufacturing method thereof, and nonwoven fabric comprising the same

The present invention relates to a heat-adhesive composite fiber having a uniform fineness, a method for manufacturing the same, and a nonwoven fabric comprising the same.

Composite fibers that can be manufactured through molding by thermal fusion using thermal energy such as hot air or heating rolls can easily obtain bulkiness, so that sanitary materials such as diapers, napkins, pads, or household products or It is widely used in industrial materials such as filters. In particular, since the sanitary material is in direct contact with the skin, it must be excellent in touch and feel, and it must quickly absorb liquids such as urine and menstrual blood. Many methods have been proposed.

In order to improve bulkiness, heat-bonding composite fibers are used to control the physical properties of crimp shape and size, fiber denier, and heat shrinkage, as well as type and viscosity characteristics of raw materials and cross-section, hollow cross-section and eccentric cross-section in cross-sectional structure. Research on the optimization of

As an example of the above research, in Korean Patent Registration No. 10-1350508, a composite fiber was prepared by composite spinning a polyester-based resin and a polyolefin-based resin, and a nonwoven fabric including the same was manufactured. However, a conventionally known polyester-based resin is used and there is no mention of a catalyst used during polymerization, but an antimony-based catalyst is usually used when polymerizing a polyester-based resin, but polyester polymerized using an antimony-based catalyst The resin has a low crystallization temperature, so there was a problem in that the fineness was not uniform when the composite fiber was prepared.

On the other hand, in order to secure the economic feasibility of the heat bonding type composite fiber, an increase in production per unit time is inevitable. Therefore, in the spinning process of the composite fiber, tens to thousands of strands are simultaneously produced in a single spinneret, and several to tens are simultaneously produced in the single spinneret, and in the post-treatment process, tens to millions of strands are simultaneously drawn and Since the heat treatment was performed, there was a potential difficulty in securing uniformity and reproducibility.

Republic of Korea Patent No. 10-1350508 (Registration Date: 2014.01.06)

The present invention has been devised to solve the above problems, and by composite spinning an olefin-based resin and a polyester-based resin having an appropriate weight average molecular weight, a heat-adhesive composite fiber having a uniform fineness is manufactured, and a uniform It is intended to manufacture a nonwoven fabric having a thickness and improved hydrophilicity.

an outer part comprising an olefin-based resin; and an inner portion comprising a polyester resin having a melting temperature of 20 to 40° C. higher than the olefin-based resin, wherein the olefin-based resin has a weight average molecular weight (Mw) of 40,000 to 100,000 g/mol, and the polyester The system resin may have a weight average molecular weight (Mw) of 35,000 to 46,000 g/mol, and the composite fiber may have a standard deviation of 0.01 to 2.0 in fineness calculated by the following Relational Equation 1.

[Relational Expression 1]

,

,

In Relation 1, σ means the standard deviation of the composite fiber fineness, x _i means the single yarn fineness of the composite fiber, N is the number of single yarn strands of the fiber sampled from the composite fiber, N = 50, μ is It is the average fineness of the sampled fibers.

As a preferred embodiment of the present invention, the olefin-based resin has a melt index (MI) measured by the ASTM D1238 method of 8 to 25 g/10 min, and the olefin-based resin is a linear polyethylene resin, It may include a polyethylene-based resin or polypropylene-based resin comprising at least one selected from a linear low density polyethylene resin, a high density polyethylene resin, and a low density polyethylene resin.

As a preferred embodiment of the present invention, the polyester-based resin is a titanium-based polymerization catalyst; and an ester reaction product; a polycondensation product obtained by polycondensation of a polycondensation product, wherein the titanium-based polymerization catalyst is 5.0 based on the amount of titanium element (Ti) in the total weight of the polycondensation product It may contain 40.0 ppm.

As a preferred embodiment of the present invention, the polyester-based resin may have a crystallization temperature of 130 to 145° C. and an intrinsic viscosity (IV; intrinsic viscosity) measured by ASTM D2857 of 0.59 to 0.70 dl/g.

As a preferred embodiment of the present invention, the cross-sectional area ratio of the outer part and the inner part of the composite fiber may be 1: 0.53 to 1: 1.85.

In a preferred embodiment of the present invention, the cross-section of the composite fiber may be circular or oval.

As a preferred embodiment of the present invention, the composite fiber may have an average fineness of 0.5 to 10 denier (de), and a fiber length of 20 to 70 mm.

For another object of the present invention, the nonwoven fabric may be manufactured by an air through bonding method or a thermal bonding method including the composite fiber.

As a preferred embodiment of the present invention, the nonwoven fabric may have a basis weight of 10 to 100 g/m ² .

According to another object of the present invention, the method for producing the composite fiber comprises the steps of: obtaining a spun by composite spinning an olefin-based resin and a polyester-based resin; and performing a post-treatment process of the spinning process, a heat treatment process, an oil coating process, and a cutting process to prepare a heat-adhesive composite fiber.

As a preferred embodiment of the present invention, the olefin-based resin has a melt index (MI) measured by ASTM D1238 method of 8 to 25 g/10 min, and a weight average molecular weight of 40,000 to 100,000 g/mol. have.

As a preferred embodiment of the present invention, the polyester-based resin has a crystallization temperature of 130 to 145° C., a weight average molecular weight of 35,000 to 46,000 g/mol, and an intrinsic viscosity (IV; intrinsic viscosity) measured by ASTM D2857 method. ) may be 0.59 to 0.70 dl/g.

As a preferred embodiment of the present invention, the stretching process may be performed at a stretching ratio of 2.0 to 4.0 under 40 to 95 ℃.

As a preferred embodiment of the present invention, the heat treatment process may be performed at 50 ~ 130 ℃ for 5 ~ 30 minutes.

The heat-adhesive composite fiber manufactured through the present invention has a uniform fineness, and hydrophilicity is improved when a nonwoven fabric is manufactured including it, so that it is suitable for a sanitary material as well as a nonwoven fabric having a uniform thickness and weight.

1 is a graph showing the results of Differential Scanning Calorimeter (DSC) performed on a polyester-based resin (Preparation Example 1) polymerized using a titanium (Ti)-based catalyst.
2 is a graph showing the results of Differential Scanning Calorimeter (DSC) performed on a polyester-based resin polymerized using an antimony-based catalyst (Comparative Preparation Example 1).

Hereinafter, it will be described in more detail through the manufacturing method of the heat-bonding type composite fiber of the present invention.

Before describing the method of manufacturing the heat-sealing composite fiber, the olefin-based resin and the polyester-based resin included in the composite fiber will be described, respectively.

First, the olefin-based resin may have a melting point of 200 to 280°C, preferably 210 to 270°C.

In addition, the olefin-based resin includes at least one selected from a linear polyethylene resin, a linear low density polyethylene resin, a high density polyethylene resin, and a low density polyethylene resin. polyethylene-based resin; Or a polypropylene-based resin; may include.

In addition, the olefin-based resin may have a melt index (MI) of 8 to 25 g/10 min, preferably 10 to 23 g/10 min, measured by the ASTM D1238 method. In addition, the olefin-based resin may have a weight average molecular weight of 40,000 to 100,000 g/mol, preferably 50,000 to 90,000 g/mol.

If the weight average molecular weight of the olefin-based resin is less than 40,000 g/mol, heat resistance and strength reduction during fiber spinning may cause non-uniform production quality such as fineness, and if it exceeds 100,000 g/mol, the flow of the molten state There may be a problem in that the machinability is reduced due to the decrease in strength and the increase in strength.

Separately, the polyester-based resin is prepared by reacting an acid component and a diol component in the first step of preparing an ester reaction product; A polycondensation reaction of a polycondensation reaction product including a titanium-based polymerization catalyst and an ester reaction product to prepare a polyester-based resin as a polycondensation reaction product; can be prepared including.

Specifically, the acid component may be used without limitation as long as it is a known acid component used to prepare a polyester-based resin, and a preferred example of the acid component may include terephthalic acid (TPA).

In addition, the diol component may be used without limitation as long as it is a known diol component used to prepare a polyester-based resin, and a preferred example of the diol component may include ethylene glycol (EG).

First, in the ester reaction of step 1, a mixture is prepared by stirring the acid component and the diol component, and the mixture is heated at 200 to 260° C., preferably at 210 to 255° C. for 150 to 240 minutes, preferably 160 It can be carried out by reacting for ~ 220 minutes.

Next, the polycondensation reaction of the second step may be performed by transferring the ester reaction product to a polycondensation reactor, and the polycondensation reaction may be performed at a pressure of 0.01 to 5 torr under 250 to 300 ° C. and preferably at a pressure of 0.1 to 4 torr under 265 to 285 °C.

Meanwhile, the titanium-based polymerization catalyst of the second step may include 5.0 to 40.0 ppm, preferably 8.0 to 37.0 ppm, based on the amount of titanium element (Ti) in the total weight of the polycondensation reaction product.

If the titanium-based polymerization catalyst is included at less than 5.0 ppm, the degree of polymerization is significantly lowered, and when it exceeds 40 ppm, the degree of polymerization is excessive and the weight average molecular weight is excessively increased, and there may be a problem in that the commercial property is lowered by coloring. .

In addition, the titanium-based polymerization catalyst may include one or more selected from a titanium alkoxide-based, titanium chelate-based and purified titanium chelate-based, preferably titanium chelate-based and It may include at least one selected from the group consisting of purified titanium chelates.

The polyester-based resin prepared by the above method may include at least one selected from a polyethylene terephthalate (PET) resin and a polybutylene terephthalate (PBT) resin.

In addition, the polyester-based resin may have an intrinsic viscosity (IV) measured by the ASTM D2857 method of 0.59 to 0.70 dl/g, preferably 0.60 to 0.68 dl/g. In addition, the polyester-based resin may have a crystallization temperature of 130 to 145 °C, preferably 133 to 142 °C. If the temperature is less than 130 ℃, a large number of crystals are formed in the heat treatment process, and as a result, there may be a problem that the fineness of the composite fiber is not uniform.

In addition, the polyester-based resin may have a weight average molecular weight of 35,000 to 46,000 g/mol, preferably 37,000 to 45,000 g/mol. If the weight average molecular weight of the polyester-based resin is less than 35,000 g/mol, a problem may occur that a continuous fibrous phase is not formed during melt spinning due to a decrease in strength, and if it exceeds 46,000 g/mol, detention during melt spinning There may be a problem in that the composite structure is formed unevenly due to the rise in the back pressure of the

In this case, the weight average molecular weight of the polyester-based resin may be adjusted by controlling the polymerization degree of the resin by polymerization time, polymerization temperature, etc., or may be adjusted according to the content of the titanium-based polymerization catalyst.

In addition, the polyester-based resin may have a melting point of 240 to 300°C, preferably 245 to 290°C.

On the other hand, the difference in weight average molecular weight between the olipine-based resin and the polyester-based resin may be 65,000 g/mol or less, preferably 10 to 22,000 g/mol, and more preferably 1,000 to 21,000 g/mol. . If the weight average molecular weight difference exceeds 65,000 g/mol, a problem in that the inner part of the composite fiber is not formed may occur due to the difference in viscosity between the polymers supplied to the inner and outer sides.

In this case, the difference in weight average molecular weight between the olefin-based resin and the polyester resin is the weight average molecular weight of the olefin-based resin minus the weight average molecular weight of the polyester resin, or the olefin-based resin from the weight average molecular weight of the polyester resin may be obtained by subtracting the weight average molecular weight of

On the other hand, as can be seen from the melting temperature of the olefin-based resin and the polyester-based resin, the polyester-based resin may have a melting temperature higher than that of the olefin-based resin by at least 20°C. Due to this, when manufacturing a nonwoven fabric including the composite fiber, when exposed to high temperature in hot air or a heating process, the fiber is melted and solidified again at room temperature to have a form of adhesion between the fibers, thereby improving the strength of the nonwoven fabric, as well as improving the strength of the fiber By maintaining the crimped shape of

Hereinafter, a method for producing a heat-bonding type composite fiber having a uniform fineness will be described in more detail.

The manufacturing method of the composite fiber comprises the steps of: obtaining a spinning product by composite spinning an olefin-based resin and a polyester-based resin; and performing a post-treatment process of the spinning process, a heat treatment process, an oil coating process, and a cutting process to prepare a heat-adhesive composite fiber.

First, the composite spinning may be performed using the olefin-based resin as an outer portion and the polyester-based resin as an inner portion.

Next, the post-treatment process may be to perform a stretching process, a heat treatment process, an emulsion coating process, and a cutting process on the radiated material.

Specifically, first, the stretching process may be carried out under 40 ~ 95 ℃, preferably at a draw ratio of 2.0 ~ 4.0 under 50 ~ 90 ℃, preferably at a draw ratio of 2.2 ~ 3.8.

In addition, before performing the heat treatment process, a crimping process may be optionally further included, and in more detail, the crimping process may be omitted so that physical crimping may not be given, and the crimping process is performed in the longitudinal direction of the fiber It can be zig-zag or omega-shaped.

Next, the heat treatment process may be carried out at 50 ~ 130 ℃, preferably under 55 ~ 120 ℃, may be carried out for 5 ~ 30 minutes, preferably for 6 ~ 25 minutes. can

Next, in the oil agent coating process, a lipophilic oil agent may be coated on the fiber surface, and the lipophilic oil agent is selected from among ionic surfactants, nonionic surfactants, anionic surfactants and zwitterionic surfactants. It may include more than one species. Through the above coating, the absorption of water, menstrual blood or urine is improved, and thus it can be used in hygiene materials, life-related materials, general medical materials, and filter materials.

Next, the cutting process may be performed depending on the intended use.

The heat-adhesive composite fiber having a uniform fineness prepared through the manufacturing method includes: an outer part comprising the olefin-based resin; and an inner portion including the polyester-based resin.

In this case, the cross-sectional area ratio of the outer part and the inner part of the composite fiber may be 1:0.53 to 1:1.85, preferably 1:0.60 to 1:1.78. If the cross-sectional area of the inner portion is less than 0.53 times the cross-sectional area of the outer portion, the breaking strength of the nonwoven fabric may be reduced during manufacturing of the nonwoven fabric, and if it exceeds 1.85 times, the adhesive strength may decrease during manufacturing of the nonwoven fabric.

In addition, the composite fiber may have a circular or elliptical fiber cross-section, and preferably may have a core-sheath shape.

In addition, the composite fiber may have a fineness of 0.5 to 10de (denier, denier), preferably 1 to 8de. In addition, the composite fiber may have a fiber length of 20 to 70 mm, preferably 30 to 65 mm.

On the other hand, for the composite fiber, the standard deviation of the fineness can be calculated by the following relation 1, and the standard deviation of the calculated fineness may be 0.01 to 2.0, preferably 0.05 to 1.8, more preferably It may be 0.10 to 1.5. If the standard deviation exceeds 2.0, the uniformity of fineness is remarkably deteriorated, and when a nonwoven fabric is manufactured including the same, the uniformity of the thickness and weight of the nonwoven fabric is lowered, thereby reducing the absorption performance may occur.

[Relational Expression 1]

,

,

In Relation 1, σ means the standard deviation of the composite fiber fineness, x _i means the single yarn fineness of the composite fiber, N is the number of single yarn strands of the fiber sampled from the composite fiber, N = 50, μ is It is the average fineness of the sampled fibers.

For another object of the present invention, it is possible to manufacture a nonwoven fabric including the composite fiber. In this case, the nonwoven fabric may be manufactured by an air through bonding method or a thermal bonding method, and preferably may be a nonwoven fabric manufactured by an air through bonding method.

In addition, the process of calendering and air-raid may be further included in manufacturing the nonwoven fabric, and detailed description of the process will be omitted in the present specification.

Meanwhile, the nonwoven fabric may have a basis weight of about 10 to 100 g/m ² , and preferably, a basis weight of about 15 to 90 g/m ² . If it is out of the above range, there may be a problem of unsuitability as a non-woven fabric for sanitary materials.

In addition, when 10 sheets of the nonwoven fabric were sampled at 1 m in the machine direction and 50 cm in the width direction, and an area of 125 mm × 125 mm was sampled at equal intervals of 5 sections in the machine direction and 3 sections in the width direction, the weight and thickness of the nonwoven fabric may be 0.01 to 1.00, preferably 0.02 to 0.30, and more preferably 0.03 to 0.25, respectively. If the standard deviation exceeds 1.00, the non-woven fabric density uniformity and moisture absorption rate may be poor due to non-uniform basis weight.

On the other hand, the nonwoven fabric can be used as an absorbent article for sanitary materials, medical hygiene materials, life-related materials, general medical materials and filter materials because the hydrophilicity is improved by being manufactured using the heat-adhesive composite fiber having the uniform fineness, More specifically, it can be used for diapers, napkins, pads, and the like.

In the above, the present invention has been mainly described with respect to the embodiment, but this is only an example and does not limit the embodiment of the present invention. It can be seen that various modifications and applications not exemplified above are possible without departing from the scope. For example, each component specifically shown in the embodiment of the present invention can be implemented by modification. And the differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

[Example]

Preparation Example 1: Preparation of polyester-based chips

Terephthalic acid was prepared as an acid component, and ethylene glycol (EG) was prepared as a diol component.

Next, an ester reactant (mixture) was prepared by mixing the acid component and the diol component.

Next, the ester reaction product was prepared by reacting the ester reactant at 250° C. for 180 minutes.

Next, a polycondensation reaction of a titanium chelate-based catalyst at a pressure of 0.5 torr under 280° C. for 180 minutes at 20 ppm based on a titanium (Ti) element and a polycondensation reaction product including the remaining amount of the ester reaction product, a polyester-based resin As a result, a polyethylene terephthalate (PET) resin was prepared.

At this time, the polyester-based resin was adjusted to polymerization time, polymerization temperature, etc. so that the weight average molecular weight was 41,800 g/mol, and the intrinsic viscosity measured by ASTM D2857 method was 0.64 dl/g. Then, the polyester-based resin was melt-extruded to manufacture PET chips.

Preparation Example 2 ~ Preparation Example 3: Preparation of polyester-based chips

A polyester-based chip was prepared in the same manner as in Preparation Example 1, but Preparation Examples 2 to 3 were carried out using the same titanium-based polymerization catalyst as in Preparation Example 1 based on titanium (Ti) element at 5 ppm and 40 ppm, respectively.

Preparation Example 4 ~ Preparation Example 5: Preparation of polyester-based chips

A polyester-based chip was prepared in the same manner as in Preparation Example 1, but by controlling polymerization time, polymerization temperature, etc., a polyester-based resin having a weight average molecular weight (Mw) of 40,050 g/mol and 45,700 g/mol, respectively, was prepared. , Preparation Examples 4 to 5 were carried out to prepare a polyester-based chip containing the polyester-based resin.

Comparative Preparation Example 1: Preparation of Polyester Chips

A polyester-based chip was prepared in the same manner as in Preparation Example 1, but Comparative Preparation Example 1 was performed using 250 ppm of an antimony trioxide catalyst as an antimony-based catalyst instead of a titanium-based catalyst.

At this time, the antimony-based catalyst was included to be 20 ppm based on the antimony (Sb) element.

Comparative Preparation Example 2 ~ Comparative Preparation Example 3: Preparation of Polyester Chips

A polyester-based chip was prepared in the same manner as in Preparation Example 1, but Comparative Preparation Examples 2 to 3 were performed using the same titanium-based catalyst as in Preparation Example 1 at 2ppm and 45ppm, respectively.

Comparative Preparation Example 4 ~ Comparative Preparation Example 5: Preparation of Polyester Chips

A polyester-based chip was prepared in the same manner as in Preparation Example 1, but by controlling polymerization time, polymerization temperature, etc., a polyester-based resin having a weight average molecular weight (Mw) of 34,300 g/mol and 46,100 g/mol, respectively, was prepared. , Comparative Preparation Examples 4 to 5 were carried out by preparing a polyester-based chip containing the polyester-based resin.

Experimental Example 1: Polyester-based resin physical properties evaluation

The polyester-based resins of Preparation Examples 1 to 5 and Comparative Preparation Examples 1 to 5 were evaluated in the following manner and shown in Table 1 below.

(1) Measurement of crystallization temperature and melting temperature

The crystallization temperature and melting temperature were analyzed through Differential Scanning Calorimeter (DSC), and the heating/decreasing rate of the analysis conditions was 10°C. In addition, the results obtained by analyzing Preparation Example 1 and Comparative Preparation Example 1 through DSC are shown in FIGS. 1 and 2 .

(2) Measurement of weight average molecular weight (Mw)

It was measured using gel permeation chromatography (GPC) and using polymethyl methacrylate as a standard.

Preparation example 1 Preparation Example 2 Preparation example 3 Preparation example 4 Preparation example 5 catalyst
(ppm) titanium 20 5 40 20 20 Crystallization temperature (℃) 139.2 132.4 140.6 139.2 139.2 Melting temperature (℃) 255.4 253.1 256.5 255.4 255.4 Weight average molecular weight (g/mol) 41,800 37,120 43,250 40,050 45,700 compare
Preparation example 1 compare
Preparation Example 2 compare
Preparation example 3 compare
Preparation example 4 compare
Preparation example 5 catalyst
(ppm) titanium - 2 45 20 20 antimony 20 - - - - Crystallization temperature (℃) 128.0 - 127.0 139.2 139.2 Melting temperature (℃) 254.8 - 257.3 255.4 255.4 Weight average molecular weight (g/mol) 42,300 No polymerization 46,500 34,300 46,100

Looking at Table 1, in Preparation Examples 1 to 3 in which the titanium-based polymerization catalyst was used in the range of 5 to 40 ppm based on the titanium element, the crystallization temperature and the melting temperature are all within the present invention, and the weight average molecular weight was appropriately formed could confirm that

On the other hand, in Comparative Preparation Example 1 using an antimony-based catalyst, the crystallization temperature was found to be less than 130 °C.

In Comparative Preparation Example 2, in which the titanium-based polymerization catalyst was used at less than 5 ppm based on the titanium element, polymerization was found to be impossible, which is expected due to the lack of a catalyst content required for activating the polymerization reaction of the monomer.

In addition, in the case of Comparative Preparation Example 2 in which the titanium-based polymerization catalyst was used in excess of 40 ppm based on the titanium element, the weight average molecular weight was found to exceed 46,000 g/mol.

On the other hand, FIG. 1 is a differential scanning calorimeter (DSC) performed on the polyester-based resin prepared in Preparation Example 1, and is a graph when the temperature increase/decrease rate is 10° C./min. As the heat history was removed as the temperature was raised repeatedly, the second temperature rise curve and the third temperature rise curve tended to be relatively flat. Therefore, looking at the first increase in temperature, the glass transition temperature of Preparation Example 1 was about 78.17 ℃, started to crystallize at about 122.46 ℃, it was found to have a crystallization temperature of about 139.25 ℃. And, it started to melt at about 241.19 ℃, it was found to have a melting temperature (melting point) of about 255.44 ℃.

On the other hand, FIG. 2 is a graph obtained by performing Differential Scanning Calorimeter (DSC) on the polyester-based resin prepared in Comparative Preparation Example 1, measured under the same conditions as in Preparation Example 1. Looking at the first temperature increase as in Preparation Example 1 (FIG. 1), the glass transition temperature of Comparative Preparation Example 1 was about 74.19° C., it started to crystallize at about 122.50° C., and it was shown to have a crystallization temperature of about 128.09° C. And, it started to melt at about 240.87 ℃, it was found to have a melting temperature (melting point) of about 254.87 ℃.

Example 1: Preparation of heat-adhesive composite fiber with uniform fineness

A polyethylene (olefin-based resin, polyethylene; PE) resin having a weight average molecular weight (Mw) of 58,000 g/mol and a melt index (MI) measured by the ASTM D1238 method of 20 g/10 min is melt-extruded to polyethylene ( PE) chips were prepared.

Then, the polyethylene chip was melted under 245° C. and spun to the outside, and separately, the polyester-based chip prepared in Preparation Example 1 was melted under 290° C. and spun to the inside, and as a result, a spun was obtained. At this time, the spinning was performed through a circular spinneret.

Then, through the post-treatment process of stretching, crimping, heat treatment and cutting of the spun yarn, a heat-bonding type composite fiber having a cross-sectional area ratio of 1:0.82 was prepared for the outer part and the inner part.

At this time, the stretching was performed at a draw ratio of 3.0 under 88°C, the crimping was formed by mechanical crimping, and the heat treatment was performed at 120°C for 15 minutes.

In addition, the oil agent coating was performed by applying a hydrophilic oil agent, and the cutting was cut so that the average fiber length was 38 mm.

Examples 2 to 5 and Comparative Examples 1 to Comparative Example 4: Preparation of heat-adhesive composite fibers

A heat-adhesive composite fiber was prepared in the same manner as in Example 1, but as shown in Tables 2-3 below, prepared in Preparation Examples 2 to 5, Comparative Preparation Example 1 and Comparative Preparation Example 3 to Comparative Preparation Example 5 Examples 2 to 5 and Comparative Examples 1 to 4 were carried out by using the polyester-based resin or by varying the cross-sectional area ratio of the outer and inner sides of the composite fiber.

Experimental Example 2: Measurement of the standard deviation of fineness of heat-adhesive composite fibers

Examples 1 to 5 and Comparative Examples 1 to 4 The standard deviation of the fineness of the spun yarn (immediately after spinning) and (after-treatment process) of the heat-adhesive composite fiber prepared in Comparative Example 4 was calculated through the following Relation 1 , shown in Tables 2 to 3 below.

[Relational Expression 1]

,

,

In Equation 1, in Equation 1, σ means the standard deviation of the composite fiber fineness, x _i means the single yarn fineness of the composite fiber, N is the number of single yarn strands of the fiber sampled from the composite fiber, N = 50, where μ is the average fineness of the sampled fibers.

Example 1 Example 2 Example 3 Example 4 Example 5 outside division polyethylene polyethylene polyethylene polyethylene polyethylene Mw 58,000 58,000 58,000 58,000 58,000 inside division Preparation example 1 Preparation Example 2 Preparation example 3 Preparation example 4 Preparation example 5 Mw 41,800 37,120 43,250 40,050 45,700 Intrinsic viscosity (dl/g) 0.64 0.61 0.66 0.64 0.67 cross-sectional area ratio
(outer part: inner part) 1: 0.82 1: 0.82 1: 0.82 1: 0.82 1: 0.82 radiation fineness (de) 5.74 5.62 5.72 5.68 5.72 Standard Deviation 0.7 2.0 1.1 0.7 1.4 complex
fiber fineness (de) 2.05 1.98 2.03 2.10 2.09 Standard Deviation 1.0 1.9 2.0 1.6 1.3

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 outside Suzy polyethylene polyethylene polyethylene polyethylene Mw 58,000 58,000 58,000 58,000
inside division Comparative Preparation Example 1 Comparative preparation example 3 Comparative Preparation Example 4 Comparative preparation example 5 Mw 42,300 46,500 34,300 46,100 intrinsic viscosity
(dl/g) 0.65 0.71 0.58 0.69 cross-sectional area ratio
(outside: inside) 1: 0.82 1: 0.82 1: 0.82 1: 0.82 radiation fineness (de) 5.73 5.80 5.69 5.71 Standard Deviation 5.4 2.4 2.7 2.5 complex
fiber fineness (de) 2.07 2.13 2.12 2.06 Standard Deviation 6.8 2.2 2.5 2.4

Referring to Tables 2 to 3, it was found that Examples 1 to 5 had less variation in fineness of the spun yarn and the composite fiber and were uniform.

On the other hand, it was confirmed that the fineness of Comparative Example 1 prepared using an antimony-based catalyst was not uniform,

In Comparative Example 2 using an excessive amount of the titanium-based catalyst, it was confirmed that the external color of the fiber was changed to yellowish, and there was a problem of poor commercialization,

In Comparative Examples 3 to 4, in which the weight average molecular weight was out of 35,000 to 46,000 g/mol, the intrinsic viscosity was not appropriate, and it was confirmed that the standard deviation of each of the spun yarn and the composite fiber fineness exceeded 2.0 and was not uniform.

Preparation Example 1: Preparation of non-woven fabric

A nonwoven fabric having an average thickness of 1.10 mm and an average weight of 19.17 g/m ² was prepared by performing an air through bonding process on the heat-bonding type composite fiber having a uniform fineness prepared in Example 1.

Preparation Example 2 ~ Preparation 5 and Comparative Preparation Example 1 ~ Comparative Preparation Example 4: Preparation of nonwoven fabric

A nonwoven fabric was prepared in the same manner as in Preparation Example 1, but using the composite fibers prepared in Examples 2 to 5 and Comparative Examples 1 to 4, Preparation Examples 2 to 5 and Comparative Preparation Examples 1 to Comparative Preparation Each of Example 4 was carried out.

Experimental Example 3: Evaluation of nonwoven fabric

The nonwoven fabrics prepared in Preparation Examples 1 to 5 and Comparative Preparation Examples 1 to 4 were evaluated in the following manner and shown in Tables 4 to 5 below.

(1) Measurement of standard deviation of weight and thickness

10 sheets of the nonwoven fabric were sampled at 1 m in the machine direction and 50 cm in the width direction, and sampled in an area of 125 mm × 125 mm at equal intervals of 5 sections in the machine direction and 3 sections in the width direction. and thickness were measured, and the standard deviation thereof was calculated.

(2) Measurement of absorption rate

In order to evaluate the absorption rate of the nonwoven fabric, the strike-through time was measured three times through the NWSP 070.7.R0(15) method. Specifically, it measures the absorbance for the first, second, and third repeated absorption. First, when 6 designated absorbent paper sheets are laid and 5 ml of artificial urine solution containing NaCl 0.9% is given, the second measurement is performed after 1 minute re-analysis. Measurements and analysis were performed after 3rd measurement after 1 minute.

In this case, the repeated measurement (first, second, and third measurements) of the absorption rate is a factor due to the density and uniformity of the nonwoven fabric and the characteristics and uniformity of the oil agent. A decrease in the uniformity of the nonwoven fabric indicates a density deviation, and the absorption time rapidly increases when the absorption rate is measured repeatedly for the first to third times. If the tertiary absorption rate exceeds 1.1s, artificial urine passes through the nonwoven fabric and is not completely absorbed in the absorbent paper, but remains in the nonwoven fabric. did.

Preparation Example 1 Production Example 2 Production Example 3 Preparation 4 Production Example 5 division Example 1 Example 2 Example 3 Example 4 Example 5 Non-woven
weight Average (g/m ² ) 19.17 18.4 20.8 20.5 20.4 standard deviation (g/m ² ) 0.9 1.5 1.2 1.1 0.9 Non-woven
thickness Average (mm) 1.10
(±0.05) 0.72
(±0.14) 1.17
(±0.11) 1.04
(±0.15) 0.87
(±0.16) absorption rate
(s) Primary 0.000 0.342 0.00 0.000 0.124 Secondary 0.634 0.745 0.641 0.543 0.843 tertiary 0.827 1.124 0.904 0.932 1.084

Comparative Preparation Example 1 Comparative Preparation Example 2 Comparative Preparation Example 3 Comparative Preparation Example 4 division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Non-woven
weight Average (g/m ² ) 21.2 20.7 20.8 21.6 Standard Deviation 2.1 1.9 2.1 2.3 Non-woven
thickness Average (mm) 0.92
(±0.27) 1.23
(±0.30) 0.96
(±0.28) 0.79
(±0.26) absorption
speed
(s) Primary 0.024 0.000 0.048 0.063 Secondary 0.741 0.841 0.938 1.235 tertiary 1.230 1.152 1.471 1.734

Referring to Tables 4 to 5, it was confirmed that Examples 1 to 5 having uniform fineness did not have large variations in the weight and thickness of the nonwoven fabric, and the absorption rate was also excellent.

On the other hand, in the case of Comparative Preparation Example 1 prepared using an antimony-based catalyst, it was confirmed that the weight and thickness of the nonwoven fabric had a large variation, which is expected because the fineness of the composite fiber was non-uniform.

In addition, it was confirmed that Comparative Preparation Examples 2 to 4 of Comparative Preparation Example 4 with too large or small weight average molecular weight not only had large variations in weight and thickness of the nonwoven fabric, but also had poor absorption capacity of the nonwoven fabric.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (10)

an outer part comprising an olefin-based resin; and an inner portion comprising a polyester resin having a melting temperature of 20 to 40° C. higher than that of the olefin-based resin.
The olefin-based resin has a weight average molecular weight (Mw) of 40,000 to 100,000 g/mol,
The polyester-based resin has a weight average molecular weight (Mw) of 35,000 to 46,000 g/mol,
The composite fiber is a heat-adhesive composite fiber having a uniform fineness, characterized in that the standard deviation of the fineness calculated by the following relation 1 is 0.01 to 2.0:
[Relational Expression 1]

,

In Relation 1, σ means the standard deviation of the composite fiber fineness, x _i means the single yarn fineness of the composite fiber, N is the number of single yarn strands of the fiber sampled from the composite fiber, N = 50, μ is It is the average fineness of the sampled fibers.
According to claim 1,
The olefin-based resin has a melt index (MI) measured by ASTM D1238 method of 8 to 25 g/10 min,
The olefin-based resin is a polyethylene-based resin comprising at least one selected from a linear polyethylene resin, a linear low density polyethylene resin, a high density polyethylene resin, and a low density polyethylene resin. A heat-adhesive composite fiber with uniform fineness, characterized in that it contains a resin or a polypropylene-based resin.
According to claim 1,
The polyester-based resin is a titanium-based polymerization catalyst; and an ester reaction product; a polycondensation product obtained by polycondensation of a polycondensation product, wherein the titanium-based polymerization catalyst is 5.0 to 40.0 based on the amount of titanium element (Ti) in the total weight of the polycondensation product. Included in ppm,
The polyester-based resin is a heat-adhesive composite fiber having a uniform fineness, characterized in that it comprises a polyethylene terephthalate (PET) resin or a polybutylene terephthalate (PBT) resin.
The method of claim 1,
The polyester-based resin has a crystallization temperature of 130 ~ 145 ℃,
A heat-adhesive composite fiber with uniform fineness, characterized in that the intrinsic viscosity (IV) measured by ASTM D2857 is 0.59 to 0.70 dl/g.
The method according to claim 1, wherein the composite fiber has a cross-sectional area ratio of an outer portion and an inner portion of 1: 0.53 to 1: 1.85;
A heat-adhesive composite fiber having a uniform fineness, characterized in that the cross-section of the composite fiber is circular or oval.
According to claim 1, wherein the composite fiber has an average fineness of 0.5 ~ 10 denier (de), and the fiber length is 20 ~ 70mm, characterized in that the heat-adhesive composite fiber with uniform fineness.
It is a nonwoven fabric manufactured including the heat-adhesive composite fiber of any one of claims 1 to 6,
The nonwoven fabric is a nonwoven fabric, characterized in that produced by an air through bonding (air through bonding) method or thermal bonding (thermal bonding) method.
8. The method of claim 7,
The nonwoven fabric is a nonwoven fabric, characterized in that the basis weight of 10 ~ 100g / m ² .
Compound spinning of an olefin-based resin and a polyester-based resin to obtain a spinning product; and
Including; and performing a post-treatment process of the spinning process, a heat treatment process, an oil coating process, and a cutting process on the spun material to produce a heat-adhesive composite fiber;
The olefin-based resin has a melt index (MI) measured by the ASTM D1238 method of 8 to 25 g/10 min, and a weight average molecular weight of 40,000 to 100,000 g/mol,
The polyester-based resin has a crystallization temperature of 130 to 145° C., a weight average molecular weight of 35,000 to 46,000 g/mol, and an intrinsic viscosity (IV; intrinsic viscosity) of 0.59 to 0.70 dl/g measured by ASTM D2857 method. A method for manufacturing a heat-bonding type composite fiber with uniform fineness, characterized in that

10. The method of claim 9,
The stretching process is carried out at a draw ratio of 2.0 to 4.0 under 40 to 95 ℃,
The heat treatment process is a method of manufacturing a heat-adhesive composite fiber, characterized in that performed for 5 to 30 minutes under 50 ~ 130 ℃.

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