KR19990030818A - Manufacturing method of nonwoven artificial leather - Google Patents

Abstract

In the present invention, microfibers are opened, carded and needle punched to produce a nonwoven felt, impregnated in an aqueous polyvinyl alcohol solution, and smoothed on a surface with a thermal calender, followed by layering by a slicing process to make a nonwoven bubble paper, and impregnated with polyurethane. The present invention relates to a method for manufacturing a non-woven artificial leather, characterized in that it performs a post-processing such as buffing, dyeing, softening after solidification and drying. According to the present invention, a non-woven fabric felt is smooth and uniform before impregnation of a polyurethane elastomer. By slicing it is possible to uniformly divide the bubble paper, it is possible to produce a non-woven artificial leather with a uniform surface, low defect rate and uniform dyeing.

Description

Manufacturing method of nonwoven artificial leather

The present invention relates to a method for manufacturing nonwoven artificial leather, and more specifically, after dissolving and removing the sea component of the island-in-the-sea composite fiber, the nonwoven fabric felt is manufactured using microfiber short fibers having a fineness of 0.01 denier or less fiber component and water-soluble. After pre-treatment with aqueous polymer solution, the surface is smoothed by thermocompression, and then the layers are separated by the slicing process and impregnated with a polyurethane elastic body. It is about.

Artificial leather is a material that is mainly impregnated with polyurethane resin and coated with non-woven fabrics, and is similar to natural leather in terms of its structure, functionality, and flexibility, but rather has the advantages of complementing the shortcomings of natural leather. It is in the spotlight as an alternative material for.

In general, artificial leather is carded and cross-wrapped a special composite fiber that can be micronized, and then needle punched to make a three-dimensional entangled nonwoven fabric, and then filled with a microporous polyurethane elastic material therein. It is made by making water.

Such artificial leather is roughly divided into suede artificial leather and silver artificial leather. Suede artificial leather is manufactured by buffing the leather-like sheet, raising the surface layer, dyeing and post-processing to form a wool layer on the surface. Mainly used for clothing, gloves, miscellaneous goods. Silver-type artificial leather is manufactured by forming a two-layer structure by wet or dry coating a polyurethane solution on a leather sheet and then embossing or laminating a polyurethane film made on a release paper having a pattern. It is mainly used for outer shell, ball outer shell, seat cover, etc.

Processes generally known as the manufacturing method of ultrafine nonwoven artificial leather are disclosed in Korean Patent Publication Nos. 90-010138, 90-011937, and 93-006245. The island-in-the-sea microfiber staple fiber is manufactured, and the nonwoven fabric felt is made by needle punching, and the aqueous polymer is removed with an aqueous alkali solution to make the constituent fibers ultra-fine and impregnated with an ester or ether type polyurethane resin to impart elasticity and dyeing of the nonwoven fabric. After the fixing treatment and the buffing, the slicing process is finally performed. However, this method has a problem that, firstly, when the slicing process is carried out in the final stage, the back deviation of the product becomes very large and it is difficult to manufacture a uniform product. In other words, the width of the shrinkage occurs as the product is subjected to the tension in the course of the various processes, and also the surface smooth state is deteriorated by the process such as elution buffing. Second, when the polyurethane is not sufficiently penetrated to the inside in the process of impregnating the polyurethane elastic body, there is a disadvantage in that the adhesion state is poor and the microfibrils of the slicing surface are easily separated and the friction strength is significantly reduced. Third, the ultrafine non-woven artificial leather has a high density, so even if the dye does not evenly penetrate into the inside of the product, the slicing product is deteriorated because it is significantly different from the dyeing state of the surface. In addition, as the slicing is performed in the final stage, it is very difficult to secure the thickness uniformity of the product. In other words, the thickness of the product continuously changes in the impregnation, elution, buffing and dyeing process steps of the nonwoven felt, and in view of this, it is virtually impossible to accurately adjust the final standard.

The present invention is to solve the problem of the after-even non-uniformity as described above, unlike the conventional manufacturing process of the non-woven artificial leather of uniform thickness by slicing the surface before the impregnation of the polyurethane elastic body smooth and uniform non-woven felt It is to provide a manufacturing method.

That is, the present invention is impregnated nonwoven fabric felt made of composite fibers in an aqueous polyvinyl alcohol solution and smoothed the surface with a thermal calender and then layered by a slicing process to make a non-woven fabric paper, polyurethane impregnated, solidified and dried, buffing, It relates to a method for producing a nonwoven artificial leather, characterized in that the dyeing and flexible processing.

Hereinafter, the present invention will be described in more detail.

The composite fiber usable in the present invention is a composite spinning of two kinds of polymer materials capable of forming filament in the form of sea / doe (海 / 島). Polyamide and polyester are used as the island component, and polyethylene or polystyrene having a melting point of 120 ° C. or less, which is different from the island component and solvent solubility, is used as the sea component, and the fineness is maintained at 3 to 5 denier. At this time, since the fineness of the composite fiber is 0.01 denier, the flexibility, strength, and fidelity of bubbles can be obtained.

The composite fiber is manufactured by high-density nonwoven fabric felt having a density of 0.20 g / cm 3 or more through opening, carding, cross lapping, and needle punching by a conventional nonwoven fabric manufacturing method.

The prepared nonwoven fabric is then stabilized by padding the nonwoven fabric with a polyvinyl alcohol water-soluble polymer solution at a concentration of 3 to 20%, drying and imparting 5 to 10% by weight of the fiber. This process is effective not only to stabilize the bubble morphology, but also to prevent the subsequent wet processing polyurethane from being in excessive contact with the fiber bundle to harden the touch.

After impregnation of the aqueous aqueous polymer solution, the surface is smoothed by calendering at a rate of 1 to 5 m / min at a temperature in the range of 80 to 130 ° C. At this time, the thickness reduction rate of the nonwoven felt due to the pressing of calender should be within 30%.

Subsequently, a slicing process is applied to produce a bubble paper of high density foil type.

Next, polyurethane wet impregnation is performed on the nonwoven fabric. Polyurethane elastomers used in this process are linear polymers composed of macroglycols, diisocyanates and low molecular weight diols having a molecular weight of 500 to 3000 and are readily soluble in dimethyl formamide (DMF). As the polyurethane elastomer used in the present invention, polyether glycol, polyester glycol, polyether polyester glycol, polyether polyester copolymer glycol, polycarbonate glycol, and the like are applicable as macroglycols. 4'-diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate or 4,4'- dicyclohexyl methane diisocyanate. In the present invention, as the low molecular weight diol, 4,4'-butanediol, ethylene glycol, and the like are used, and a diamine-based chain extension agent is also applicable. A surfactant, a coloring pigment, an antioxidant, and the like are added to the DMF solution of the polyurethane elastomer to be used as an impregnation solution of 12 to 20%. After impregnation, the polyurethane is solidified in the non-solvent system or the non-solvent and solvent mixture system of the polyurethane, washed with hot water at 50-70 ° C., and then completely removed and dried. Flexible elasticity, tightness, etc. are expressed, and the filling feeling like natural leather is given.

Next, sea component is removed by an alkali weight reduction method to perform an ultrafine fiber step. At this time, when the sea component is polyethylene or polystyrene, it is removed with toluene or perchloroethylene. For example, polyethylene or polystyrene is completely decomposed and removed by treatment in toluene at 80 to 100 ° C. for 20 to 50 minutes. At this time, the nonwoven fabric has some thickness reduction due to the removal of the sea component, but the shape is maintained and the elongation in the longitudinal direction by the mechanical tension is not large.

Next, the surface of the leather-like sheet material thus obtained is buffed using sandpaper of No. 240 or No. 400 to trim the surface wool.

Subsequently, if the fiber used is polyamide, it is dyed with a conventional metal dye or acid dye, and if it is polyester, it is dyed with a high-speed rapid dyeing machine with a disperse dye.

After the above process is completed, finally, the functional preparation treatment such as softener, water repellent, antistatic agent, etc., produces a non-woven artificial leather with dense bubbles and beautiful appearance.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

The polyamide having a relative viscosity of 2.8 as a constituent component, the melting point of 103 ° C. and polyethylene having a melt index (MI) of 70 as a sea component were mixed and spun at a 50:50 weight ratio between the island component and the sea component. Maintain fineness of 5 denier, length is 45 to 60mm, number of crimps is 15 to 20 per unit length (inch), strength is 2 to 4g / d, elongation is 60 to 100%, and then opening, carding, A non-woven fabric with a density of 0.20 g / cm3 or more is produced through cross lapping and needle punching, impregnated and dried in a 10% polyvinyl alcohol solution, and then dried at a temperature of 80 to 130 ° C. at a speed of 1 to 5 m / min, and a nonwoven fabric. Calendering the surface to 80% of the bubble paper to smooth the surface, and then applying a slicing process to prepare a high density paper type bubble paper, and to prepare a polyurethane solution (DIC Co., Ltd. MP-105) having a solid content of 30% Dimethylformamide Soluble in, impregnated, solidified and dried in a 12-20% solution. Then, the polyethylene was eluted and removed using toluene at about 80 ° C, surface buffed using No.200 and No.400 abrasive paper, dyed with a metal dye, followed by fixing, antistatic agent treatment, and flexible processing. After producing the product through to evaluate the properties are shown in Table 1.

Comparative Example 1

The mixture was spun with a polyamide having a relative viscosity of 2.5 and a polyethylene having a melt index (MI) of 40 to 70 so that the fineness was 3 to 5 denier, the strength was 2 to 4 g / d, and the elongation was 60 to 100%. To 60 mm, the number of crimps to prepare the non-woven felt by preparing a staple fiber to be in the range of 15 to 20 per unit length (inch) and then physically bonded three-dimensionally through opening, carding, cross-lapping and needle punching. The nonwoven fabric is sized at a weight of 500 to 800 g / m 2 and a thickness of 2.0 to 3.0 mm, and punched at 3000 times of needle density (PPSC) during needle punching to produce a high density nonwoven felt. In order to minimize the friction between the static electricity generated in the needle punching process and the machine, the antistatic agent and the smoothing agent are treated with staple fibers for improvement. The prepared non-woven felt is separated by ultra-microfiber seaweed polyethylene into perchloroethylene or toluene using a special solvent dissolution apparatus, and the separated polyethylene and the solvent are recovered through a recovery treatment apparatus. After elution, the polyvinyl alcohol, a water-soluble polymer, is treated to fix the shape, and impregnated with an ester type or ether type polyurethane resin to impart elasticity to the nonwoven artificial leather. The impregnation ratio of the polyurethane resin is 30% based on solid content. To maintain the weight ratio. After that, it is dyed and fixed to ensure high fastness, followed by buffing and softening to finish the final surface. According to the use, the final product was divided into two parts through slicing, and then the product was evaluated and the properties thereof were shown in Table 1 below.

Comparative Example 2

Polyamide having a sulfuric acid relative viscosity of 2.8 and a water-soluble polymer were produced by composite spinning to form island-in-the-sea microfibers, with fineness ranging from 3 to 5 denier, strength from 2 to 4 g / d, elongation from 60 to 100%, and length from 45 to 60 mm, the number of crimps to prepare a non-woven felt by preparing a staple fiber to be in the range of 15 to 20 per unit length (inch) by three-dimensional physical bonding through opening, carding, cross-lapping and needle punching. The nonwoven fabric has a weight of 500 to 800 g / m 2, a thickness of 2.0 to 3.0 mm, and punches at least 3000 times of PPSC during needle punching to produce a high density nonwoven felt. In order to minimize the friction between the static electricity generated in the needle punching process and the machine, the antistatic agent and the smoothing agent are treated with staple fibers for improvement. The prepared nonwoven fabric was eluted with a 2% aqueous alkali solution in a winch or a circular processing machine to convert short fibers into 0.05 denier microfiber, and then fixed in polyvinyl alcohol treatment to fix the form and use an ultra-soft ester resin. The ratio between polyurethane and dimethylformamide solvent is adjusted to about 100: 300 and wet coated. Then, through the buffing process, evenness of the front and back of the nonwoven fabric is uniformed, and the backside deviation of the surface is improved. Next, the top and bottom of the nonwoven fabric is separated up and down within the range of 5% of the rear deviation by slicing, and the microfiber nonwoven fabric is dyed using a metal dye and a fixing agent in a high pressure winch dyeing machine. Finally, the surface of the dyed nonwoven fabric was buffed to finalize the surface preparation state, and the characteristics thereof are shown in Table 1.

Thickness deviation Durability (slicing side) Dyeing Tea (Surface) Weight reduction rate at surface friction Dust generation Example 2% 1.5% radish Similarity Comparative Example 1 8% 6.0% U Distinct Comparative Example 2 5% 4.5% U Distinct

Surface friction test condition: It is a value measured 50 times by a wear tester.

According to the present invention, it is possible to uniformly divide the bubble paper by slicing in a non-woven felt state with a smooth and uniform surface. Therefore, through various post-processing steps such as polyurethane impregnation, elution, buffing, and dyeing, the failure rate due to slicing can be significantly reduced after the thickness deviation is increased, and after slicing, the polyurethane becomes internal as the polyurethane is impregnated, solidified and dried. It is possible to solve the problem that the adhesion state of the sliced surface is not sufficiently penetrated or the fine fibrils are easily released and the friction strength is significantly decreased. In addition, the application of the slicing before the post-processing process enables accurate product thickness estimation in production.

Claims (2)

Nonwoven fabric felt is manufactured by needle punching composite fiber, impregnated in polyvinyl alcohol water-soluble polymer solution, and smoothed surface with thermal calender, and then divided into layers by slicing process to make non-woven fabric paper, polyurethane impregnation, coagulation and drying, buffing, Method for producing nonwoven artificial leather, characterized in that the dyeing, flexible processing. The method of claim 1, wherein the heat treatment conditions of the calendar is a non-woven artificial leather, characterized in that the reduction rate of the thickness of less than 30% by compression at 80 to 130 ℃.