KR20080078966A - Artificial leather with excellent elasticity and method of manufacturing the same - Google Patents

Abstract

An artificial leather with the excellent elasticity and a manufacturing method thereof are provided to manufacture the artificial leather with high extension recovery rate, dyeability and fastness by using polyester based materials and by optimizing the process condition, and to be used in various application. An artificial leather is formed of ultra fine yarn having thickness of less than 0.3 denier and polyurethane. A part or a whole part of the ultra fine yarn is formed of a polyester based fiber containing 10-60 weight% poly-tetramethylene-glycol constituent. A part of the ultra fine yarn is formed of a polyester based fiber not containing the poly-tetramethylene-glycol constituent. The main body of the polyester based fiber is formed of one selected from a group consisting of a polyethylene-terephthalate, a polypropylene-terephthalate and a polybutylene terephthalate. The extension recovery rate of the length and the width direction of the artificial leather is better than 85%. A non-woven fabric is formed of a two composite complex yarn. A polyurethane elastomer is put on the non-woven fabric. The artificial leather is manufactured by thinning the two composite complex yarn to be fine and thin, and by buffing, grinding and coating the ultra fine yarn.

Description

Artificial leather with excellent elasticity and method of manufacturing the same

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing various length codes applied to artificial leather in calculating the recovery rate in the width direction and the length direction.

The present invention relates to an artificial leather excellent in elasticity and a manufacturing method thereof, and more particularly, to an artificial leather and a method of manufacturing the same, which are excellent in elasticity and useful for materials such as clothes, gloves, furniture and boots.

Artificial leather composed of a nonwoven fabric in which microfibers are intertwined in three dimensions and a polyurethane resin (polyurethane elastomer) impregnated in the nonwoven fabric has a soft texture and unique appearance similar to that of natural leather, and thus is widely used as a material for clothing or gloves. have.

Recently, the development of artificial leather with high functionality has been actively progressed beyond the steps of imitating the soft texture and unique appearance peculiar to the existing natural leather.

In particular, there is a demand for artificial leather having excellent elasticity (stretch recovery) during use so as to improve the fit and to be suitable for use in areas with many bends.

The stretch recovery force of artificial leather is due to the polyurethane elastomer, and thus, when the polyurethane is in a completely continuous phase, it is easily stretched up to several hundred percent and almost completely recoverable. However, in the case of artificial leather, polyurethane serves as a filler between the ultrafine fibers and exists in the form of a sponge with many fine and uneven holes. Due to this structure, strength is concentrated in the thin and weak areas of the polyurethane during elongation deformation and there is a limit to full recovery because the recovery of the stretched nonwoven fabric is insufficient to recover the stretched nonwoven fabric even if some breakage or breakage does not occur. . In addition, the smaller the filling amount of polyurethane, the thinner and weaker the area of the sheet, so the resilience of recovery becomes smaller. Therefore, in order to improve the stretch recovery power, it is preferable to fill the polyurethane content in as many and continuous structures as possible.

As a conventional technique for imparting elasticity to artificial leather, U.S. Patent No. 4,833,012, European Patent No. 1,445,371, Korean Patent Publication No. 1999-76034, and Korean Patent Publication No. 2004-71654, etc. A method of using a spandex yarn) is proposed.

However, according to the above method, there is a limitation of material selection in order to mix elastic fibers, and the cost burden is large because expensive elastic fibers are applied, and the surface is very rough and coarse because the elastic fibers are exposed to the surface when manufactured with suede nails. There was a problem of getting lost. In particular, it is impossible to manufacture a uniform product due to the serious problems of dyeability and color fastness and difficulty in controlling tension during the manufacturing process.

On the other hand, Japanese Patent Laid-Open Nos. 2004-92005 and 2004-91999 propose a method of manufacturing artificial leather by inserting a stretchable knitted fabric including polyurethane elastic yarn in the middle of a short fiber web layer by a water jet method. Doing.

However, according to the above method, since the knitted fabric is made only of polyurethane elastic yarn, insertion by needle punching becomes quite difficult.

Therefore, it is produced by bonding by the water jet method. Bonding by the water jet method creates a water track (a valley in the machine direction).

In the case of suede-like fabrication by this method, the surface state is not uniform and many unevenness is felt, so it is not satisfactory as artificial leather of high-quality materials such as clothing. Similarly, Japanese Patent Application Laid-Open No. 2000-336581 and Japanese Patent Application Laid-Open No. 2003-239178 also include a potential crimping yarn containing polytrimethylene terephthalate as a main component in the middle of a single fiber web layer by a water jet method. It is proposed a method, but the method has an aspect that the surface state is not satisfactory.

On the other hand, Korean Patent No. 379,072 proposes a method for joining a fabric in which spandex yarn or stretch yarn as warp and weft yarns by a short fiber web and a needle punching method.

However, according to the method, the fineness of the warp and weft yarn constituting the fabric is very thick, at a level of 200 to 300 denier. Since the uniformity of the surface of the leather is influenced by the thickness of the fabric or knitted fabric inserted into the leather, when manufactured with the fineness, artificial leather, such as a garment for low thickness, is exposed to the surface of the leather. There is a lack of luxury and an unsatisfactory aspect

An object of the present invention is to produce a non-woven fabric in a conventional needle punching method by producing a two-component composite fiber made of a stretchable and dyeable polyester resin with a fiber-forming component to solve such conventional problems and cost It is for producing artificial leather having a small amount of elasticity in both directions in length and width.

The present invention can be produced by the conventional needle punching method by applying the short fibers of the two-component composite fibers made of a stretchable resin material as a fiber-forming component, the dyeing and fastness is good and the elasticity satisfies both the longitudinal and the width direction By manufacturing the artificial leather having a conventional synthetic polyurethane-based microfiber yarn to overcome the limitations of the manufacturing process of the artificial leather and to provide a suede artificial leather with a uniform surface state.

Since the bicomponent conjugate fiber used in the present invention contains the polytetramethylene glycol component in the fiber-forming component, the amorphous region is large and long, so that the stretch recovery is excellent. The artificial leather product to which the ultrafine yarn containing 10 to 60% by weight of the polytetramethylene glycol component has an elongation recovery rate of 85% or more.

In addition, since the elasticity is not too large, such as polyurethane, the elongation due to tension is not large during the manufacturing process, and thus artificial leather can be manufactured independently without mixing with the non-stretchable material.

In addition, since it is basically a polyester-based material, the dyeability and color fastness are also much better than that of the polyurethane-based. In the present invention, by controlling the content of polytetramethylene glycol, it is possible to produce an excellent artificial leather having satisfactory dyeing and fastness by expressing elasticity suitable for a desired use and optimizing the reducing washing conditions during the dyeing process.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The artificial leather excellent in elasticity according to the present invention is an artificial leather made of ultra-fine fibers having a thickness of 0.3 denier or less and polyurethane, wherein all or part of the ultra-fine yarn contains 10 to 60% by weight of polytetramethylene glycol component It is characterized in that the fiber.

In addition, the manufacturing method of artificial leather with excellent elasticity according to the present invention is a process for producing a nonwoven fabric of two-component composite fibers in the form of short fibers composed of an extract component and a fiber-forming component and a process for imparting a polyurethane elastomer to the nonwoven fabric In the preparation of artificial leather through the process of eluting and extracting the extract component in the two-component composite fiber, buffing grinding and dyeing process, the fiber-forming component is 10 to 60% by weight of polytetramethylene glycol component Two-component composite fiber (A), which is a polyester resin to be used alone, or two-component composite fiber (A) and a two-component fiber, wherein the fiber-forming component is a polyester resin that does not contain a polytetramethylene glycol component. It is characterized by using a composite fiber (B) together.

Conventional artificial leather is composed of ultrafine fibers of 0.3 denier or less and polyurethane elastomer. In the present invention, all or part of the ultrafine yarn is manufactured from a flexible material as a means for exerting elasticity. Polyurethane-based, polytrimethylene terephthalate and the like are known as stretchable materials. In the present invention, a polyester-based resin containing a polytetramethylene glycol component is used.

However, more importantly, the elasticity and dyeability of the product vary greatly depending on the content of the polytetramethylene glycol component in the ultrafine yarn. In particular, dyeing fastness is very important when manufactured in suede bath, it is very important to properly control the content of polytetramethylene glycol.

In the present invention, all or part of the ultrafine yarn is a polyester fiber containing 10 to 60% by weight of the polytetramethylene glycol component.

As the manufacturing method of the ultra-fine yarn, all the usual methods of manufacturing the ultra-fine fibers such as island-in-the-sea, split type, and direct spinning type may be applied. Microfiber yarns are completed through a micronization process if necessary, and the fineness after micronization is usually 0.3 denier or less. In particular, in the case of manufacturing a microfiber with a bicomponent composite fiber composed of an extract component and a fiber forming component, when the extract component is extracted through an extraction process, the fiber forming component remaining after the extraction process becomes a microfiber.

The polymer constituting the fiber-forming component is produced through a condensation polymerization process which is a conventional polyester polymerization method, and a component having an acid and a glycol terminal is used as a polymerization raw material. In the case of polyethylene terephthalate, terephthalic acid (acid) and ethylene glycol are used in an equivalent ratio of about one to one. In the case of polybutylene terephthalate, terephthalic acid (acid) and butylene glycol are used. The polyester fiber containing polytetramethylene glycol is characterized in that a part of the glycol which is one of the polymerization raw materials is replaced with polytetramethylene glycol. The polytetramethylene glycol preferably has a molecular weight of 1,500 to 2,000. The content of polytetramethylene glycol can be controlled while adjusting the total equivalent ratio of glycol to terephthalic acid to about one to one.

In the present invention, the polyester fiber containing polytetramethylene glycol has a content of polytetramethylene glycol of 10 to 60% by weight. When the content of polytetramethylene glycol is large, the elasticity of the ultrafine yarn tends to be improved, and when the content is less, the elasticity is lowered. Since polytetramethylene glycol forms a long chain of amorphous regions, it serves as a soft segment and thus has the property of being easily stretched as in polyurethane. However, when the content of polytetramethylene glycol exceeds 60% by weight, there is a disadvantage in that the strength of the fiber is excessively extended and the recovery force is reduced. In addition, when the content of polytetramethylene glycol is less than 10% by weight, there is a problem in that the elasticity is hardly exhibited. Therefore, it is very important to adjust the content properly. In another aspect, the content of polytetramethylene glycol significantly affects the dyeability. Conventional polyester fiber is easily dyed with a disperse dye, it is also excellent in color fastness. Disperse dyes penetrate into the amorphous region under high temperature and high pressure, and dyeing and color fastness are expressed by a mechanism that does not come out at room temperature and normal pressure. The polyester fiber containing polytetramethylene glycol has more amorphous regions and thus dyes easily even at normal temperature and pressure. Is more likely to come out. This means that the dye fastness can be reduced. Therefore, excessively high content of polytetramethylene glycol may cause undesirable results in terms of color fastness, so it is very important to limit appropriately.

As the main body of the polyester fiber, one or more selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate may be used. In the present invention, the main means a main polymer of a polymer other than polytetramethylene glycol.

In addition, a part of the ultrafine yarn of the present invention may be a polyester fiber containing polytetramethylene glycol, and the other part may be an ultrafine fiber not containing polytetramethylene glycol. By mixing ultra-fine fibers that do not contain polytetramethylene glycol, better results can be obtained in terms of color and color fastness, so that the mixing ratio can be appropriately adjusted according to the purpose and use.

It is preferable that the recovery rate in the longitudinal direction and the width direction of the artificial leather product manufactured by imparting the above characteristics is 85% or more. If the stretch recovery rate is less than 85%, it may feel that the elasticity is insufficient. In the present invention, by using a stretchable material for the ultrafine fibers used in the nonwoven fabric, it is possible to give an 85% or more stretch recovery rate regardless of the longitudinal direction.

Artificial leather having excellent elasticity of the present invention is manufactured through a series of processes as follows.

First, the fiber-forming component is used alone of the two-component composite fiber (A), which is a polyester resin containing 10 to 60% by weight of polytetramethylene glycol component, or the two-component composite fiber (A) and fiber formability The bicomponent composite fiber (B), which is a polyester-based resin containing no polytetramethylene glycol component, is used together to prepare a single fiber raw material through a crimping and cutting process. In this case, polyethylene, polystyrene, or a copolyester-based polymer may be used as an extract component constituting the two-component composite fiber.

The said raw material is a super microfiber fiber whose thickness becomes 0.3 denier or less after making it ultra-fine through processes, such as elution or a dividing | dividing process.

The fiber is prepared into a short fiber web through a carding process or the like to produce a high density nonwoven fabric by a needle punching method. Occasionally, in order to reinforce the shape of a nonwoven fabric, a fabric or knitted fabric is inserted into a scrim and joined. The apparent density of the high density nonwoven fabric is about 0.200 to 0.250 g / cm 3.

Next, the nonwoven fabric sheet prepared as described above is padded with a water-soluble polymer solution such as polyvinyl alcohol or carboxymethyl cellulose at a concentration of 3% to 15% and dried to give 5 to 20% by weight based on the weight of the fiber. This process is effective in preventing subsequent wet processing polyurethanes from excessively adhering to the micronized fibers to harden the feel.

Next, a polyurethane wet impregnation process is performed on the nonwoven fabric padded with a water-soluble polymer. Polyurethane elastomers used in this process are readily dissolved in dimethyl formamide (hereinafter referred to as "DMF") as a linear polymeric material consisting of macroglycols, diisocyanates and low molecular weight diols or diamines, or as some crosslinkable polymeric materials. As the macroglycol used in the present invention, polyether glycol, polyester glycol, polyether polyester copolymerized glycol, polycarbonate glycol and the like are applicable.

In the present invention, as the low molecular weight diol, 4,4'-butanediol, ethyl glycol, and the like may be used, and diamine-based chain extension agents such as methylene-bis- (4,4'-phenylamine) may be applied. Surfactant, pigment, functional particles, etc. are added to the DMF solution of the polyurethane elastomer to dilute the concentration, and use it as an impregnation solution.

After the sheet is dipped into the impregnation solution, the polyurethane is solidified in an aqueous solution, washed with hot water at 50 to 80 ° C., and completely dried after removing the filled water-soluble polymer. The content of the polyurethane after drying is preferably 20 to 50%.

Subsequently, the elution component is removed with a solvent or caustic soda aqueous solution which can extract or divide the extract component, and the fiber is subjected to an ultrafine step.

If the extraction component is a copolyester, it is treated with 5-15% caustic soda solution in a continuous or discontinuous batch manner to decompose the extract component. If the extract component is polyethylene or polystyrene, toluene or perchloroethylene or trichloroethylene To remove it.

For example, the copolyester as an extract component is completely decomposed and removed by treating with 10% aqueous caustic soda for 5 to 10 minutes at 100 ° C. At this time, the nonwoven fabric has a small thickness, shrinkage, and compression, thereby improving the apparent density of the sheet surface.

Next, the surface of the leather-like sheet thus obtained is ground with a buffer equipped with sandpaper of appropriate roughness to form hair on the surface and trim the wool. The roughness of the sandpaper is selected differently according to the use, but it is preferable to use 150-400 mesh.

The leather-like composite sheet fabric formed with the wool is dyed in a high pressure rapid dyeing machine using a dispersion dye which is a conventional polyester dyeing method. However, in order to prevent the lowering of the fastness due to the inclusion of polytetramethylene glycol, it is preferable to perform a severely reduced washing process. It is good to remove the disperse dye penetrating into a large amorphous region such as polytetramethylene glycol as clean as possible. Lastly, if the dyeing product is subjected to flexible and functional drug processing and the like, a high-quality artificial leather suede having a uniform surface wool, excellent dyeing fastness and excellent elasticity is produced.

By the above process procedure and detailed method, it is possible to produce artificial leather having excellent elongation recovery rate and good dyeing fastness in the longitudinal width direction.

In addition, the leather-like composite sheet fabric having the above described wool may be coated on the surface with a polyurethane or the like.

By forming a coated surface with an appropriate thickness and subjecting it to surface finishing, such as embossing, it is possible to produce a silver artificial elastic leather having no wool on the surface.

In the present invention, various physical properties were evaluated by the following method.

The thickness of the fiber

The cross-sectional samples of the manufactured artificial leather were taken and subjected to a preparation process such as gold coating, and the artificial leather cross-section pictures were taken at an appropriate magnification so that the size could be easily seen through a scanning electron microscope [SEM] analyzer. After evaluating the cross-sectional diameter of a single strand of fiber shown in the picture and converting it to the actual value, the fineness was obtained through the following formula.

Fineness (Denia) = 9πD ² ρ / 4000

π: circumference

D: fiber cross section diameter (μm)

ρ: fiber density value (g / cm 3)

Ex) Nylon 1.14, Polyethylene terephthalate 1.38

Elongation recovery rate (%)

Manufactured artificial leather or longitudinal or widthwise elongation recovery was obtained as follows.

-Measuring equipment; INSTRON's tensile tester

- Measuring conditions ; Tensile Method: Repeated Constant Velocity Stretch Method (KS K 0352 Method Application)

Gripping length of the test piece: 8 cm

Tensile Speed: 300mm / min

Repeated elongation to recovery elongation range: 0 to 20% (0 to 1.6 cm)

Number of repeated loads: 5 consecutive recovery

- How to measure

          (1) Specimen of test piece:

              -When measuring the elongation recovery in the longitudinal direction: longitudinal direction x width direction; 20 cm x 2.5 cm

              -When measuring the elongation recovery in the width direction: width direction x length direction; 20 cm x 2.5 cm

(2) As described above, the sample was held at a distance of 8 cm, stretched to 20% (L = 1.6 cm), and then recovered five times in succession.

(3) After leaving for 2 hours after the test, measure the length (L ') longer than the initial length.

(4) The elongation recovery rate in the longitudinal width direction at 20% elongation was evaluated by the following equation.

[Wherein L ₀ is the original length of the sample (8.0cm), L is the length (1.6cm) drawn up to 20% of the test piece, and L 'is the length of the test piece after 2 hours of repeated loads ]

Dyeing Fastness

10 Experts The expert evaluates in gray scale which is a common standard method. If it is judged that more than 8 people are more than 3 grades aiming at 3rd grade or more about washing fastness and friction fastness, ◎ Separated by

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

However, the scope of the present invention is not limited by the following examples.

Example 1

A polybutylene terephthalate polymer containing 33% by weight of polytetramethylene glycol is polymerized to produce a polymer, and 70% by weight of this polymer is used as a fiber-forming component, and 30% by weight of copolyester is used as an extract component. And stretching to prepare the bicomponent conjugate fibers, followed by and through the crimp cutting process, the bicomponent conjugate fibers having a length of 51 mm and a single yarn fineness of 2.5 denia and having a number of microfiber fibers (fibrous forming component) in the monofilament with 36 Short fibers were prepared. The short fibers were subjected to a carding-cross lapping process to form a web and needle punched to prepare a nonwoven fabric to form a sheet having a density of 0.220 g / cm 3. The nonwoven sheet was then padded and dried with an aqueous 10% polyvinyl alcohol solution to give 10% by weight to the fiber weight. Immediately thereafter, the polyurethane elastomer of the polyether polyester copolymer glycol type was diluted in dimethylformamide (DMF), and the composite sheet was dipped in an impregnation solution having a concentration of 13%, and then solidified in an aqueous polyurethane solution. It was washed with hot water solution to completely remove the polyvinyl alcohol polymer and dried. The content of polyurethane after drying was 30 weight%. The composite sheet composed of the fiber and the polyurethane was continuously treated at 100 ° C. in a 10% aqueous solution of caustic soda to completely remove the copolyester as an extract component and to make the fiber fine by leaving only the fiber-forming component. At this time, the micronized fiber had a thickness of 0.05 denia. Subsequently, roughening # 240 sandpaper was applied to produce a stretchable composite sheet for artificial leather by cutting a part of the microfiber fibers and raising them by buffing. Next, after dyeing in a high-speed rapid dyeing machine with a good color fastness dye, reduced washing twice with an alkali reducing agent and dried. Subsequently, suede-type artificial leather was manufactured through a water repellent and antistatic agent treatment process and a Momi soft process. The physical properties of the stretchable artificial leather prepared as described above are shown in Table 2 below.

Examples 2-3 and Comparative Examples 1-2

The composite sheet-like artificial leather was manufactured in the same manner as in Example 1 except for changing the composition and the composition of the fiber-forming component in the bicomponent composite fiber as shown in Table 1 below, and the physical properties thereof were shown in Table 2 below.

     Manufacture conditions division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Content of Polytetramethylene-Glycol in Fiber Forming Components (wt%) 33 21 50 5 70 Main agent of fibrous component Polybutylene-terephthalate Polypropylene-terephthalate Polyethylene-terephthalate Polybutylene-terephthalate Polyethylene-terephthalate

Artificial leather property evaluation result division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Color fastness ◎ ◎ ○ ◎ × Longitudinal elongation recovery 91% 88% 93% 80% 95% Width Elongation Recovery 93% 87% 94% 88% 95%

The artificial leather of the present invention has an excellent recovery rate in the longitudinal direction and the width direction of 85% or more, and has good dyeing and fastness. In addition, the present invention is not rough and uniform surface compared to the conventional stretch artificial leather. Therefore, the artificial leather of the present invention is suitable as a material for clothing, a material for gloves, a material for furniture, a material for boots, etc. requiring a supply amount.

Claims (6)

In artificial leather composed of ultra-fine fibers and polyurethane having a thickness of 0.3 denier or less, all or part of the ultra-fine yarn is polyester fiber containing 10 to 60% by weight of polytetramethylene glycol component. Leather. The artificial leather having excellent elasticity according to claim 1, wherein a part of the ultrafine yarn is a polyester fiber containing no polytetramethylene glycol component. The artificial leather having excellent elasticity according to claim 1 or 2, wherein the main body of the polyester fiber is at least one member selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate. The artificial leather with excellent elasticity according to claim 1, wherein the recovery rate in the longitudinal and width directions of the artificial leather is 85% or more. A process for producing a nonwoven fabric with bicomponent composite fibers in the form of short fibers composed of an extract component and a fiber forming component, a process for imparting a polyurethane elastic body to the nonwoven fabric, and eluting the extract component in the two component composite fibers to fine In manufacturing artificial leather through the process of buffing, buffing and dyeing or coating, the two-component composite fiber (A) is a polyester resin containing 10 to 60% by weight of a polytetramethylene glycol component. ) Is used alone, or the bicomponent conjugate fiber (A) and the bicomponent conjugate fiber (B), which is a polyester resin in which the fiber forming component does not contain a polytetramethylene glycol component, is used together. Manufacturing method of artificial leather with excellent elasticity. The method for producing artificial leather having excellent elasticity according to claim 5, wherein the main agent of the polyester resin is at least one member selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate.

Images