KR890000246B1 - Manufacturing process of artificiality leather - Google Patents

Abstract

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Description

Manufacturing method of suede artificial leather with excellent resilience and touch

The present invention relates to a method of manufacturing artificial leather with excellent resilience and feel, and in particular, suede artificial leather with wet leather treated primarily to improve flexibility, and then dry to increase resilience and fusiformity. It relates to a method of manufacturing.

Conventionally, methods for improving the properties of suede artificial leather have been proposed. Among them, according to Japanese Patent Publication No. 59-14593, a nonwoven fabric is impregnated with an aqueous polyurethane emulsion, and then dimethylformamide (hereinafter referred to as DMF). It is described to improve the flexibility of the non-woven fabric by swelling the polyurethane treated primarily by imparting a polyurethane, and this process is described in more detail to prepare a flexible fiber sheet to impart a filler therein The first step to purify the flexible fibers, the second step to fine-tune the viscoelastic material, the third step to impart and solidify the viscoelastic material, the fourth step to swell the viscoelastic material, and the fifth step to remove the fillers. As the viscoelastic material, an aqueous non-reactive polyurethane emulsion is used, which is simply a low molecular weight material. As prone to weak one-component polyurethane embrittlement followed by DMF as has been pointed out a disadvantage that is not durable in a subsequent step such as dyeing.

In addition, Japanese Patent Publication No. 59-40948 discloses a method of manufacturing a suede-like artificial leather having excellent rebound elasticity by dry treating a nonwoven fabric with a heat-reactive polyurethane prepolymer alone. In Esau, by adopting only the dry processing method, the resilience of the nonwoven fabric is increased, but the touch and the drape are deteriorated, so that the soft touch and texture peculiar to the wet processing method are not expressed.

Therefore, the present invention is to give a polymer elastic material such as polyurethane to a non-woven fabric made of a composite fiber capable of microfiber in order to solve the above-mentioned defects of suede artificial leather manufactured according to the conventional method and then special processing The purpose of the present invention is to provide a method of manufacturing suede artificial leather with improved flexibility and excellent resilience and feel.

Hereinafter, the present invention will be described in detail.

The present invention is a method of manufacturing a suede-like artificial leather, the first step of producing a non-woven fabric of a composite fiber capable of microfibers and the second step of minimizing the fiber and imparting an elastic polymer material, buffing the fiber surface ( Buffing) and a fourth step of imparting a thermally reactive polyurethane prepolymer and a fourth step of imparting a heat-reactive polyurethane prepolymer. .

According to the present invention, the elastic polymer material in the second step is selected from synthetic rubbers such as nitrile butadiene rubber and styrene butadiene rubber and DMF-soluble linear polyurethane having an average molecular weight of 100,000 or more. As the type polyurethane prepolymer, an aqueous emulsion formed by blocking the isocyanate group contained at its terminal with bisulfite is used. In addition, the amount of elastic polymer material added in the second step is 40 to 120% by weight of the fiber weight after removing the sea component, the amount of heat-reactive polyurethane prepolymer in the fourth step is fiber The amount is 1 to 20% by weight based on the weight.

Referring to the present invention in more detail as follows.

The present invention is to produce a non-woven fabric or woven fabric using an ultrafine fiber and then to give a polyurethane elastic body to produce artificial leather, but it is prepared by a known technique, but the composite fiber used in the present invention to form a filament It is a composite spinning of two kinds of high molecular materials in a special form, the non-woven fabric is produced, and then only one component of the two kinds of high-molecular materials is dissolved and removed at a suitable time during the processing process and the Among the split type composite fibers in which the two types of components are separated from each other and made fine, the island-in-the-sea composite fiber having a fineness of 0.001 to 0.5 denier when the micron is finely used is used. It is processed so that it can exert an excellent effect not only in process but also in quality. And so.

In this case, as the island component of the island-in-the-sea composite fiber, polyethylene terephthalate, nylon-6, and polyacrylonitrile may be used, and the sea component may be selected from polystyrene, polyethylene, polyester, and polyamide. A mechanical crimp of 10 to 20 pieces / inch is given to the composite continuous filament fibers thus obtained, cut into a certain length, carded with a roller carding machine, and then crosslapping or random carding. The fabric is manufactured using air with air.Because the fabric produced in this way has a two-dimensional shape, it is passed through a needle room with a valve, and then needle punching. By interweaving in three dimensions in the thickness direction to increase the density and to form a stabilized nonwoven fabric.

The nonwoven fabric thus prepared is treated with a filler such as polyvinyl alcohol to stabilize the form in order to facilitate the ultrafine fiber and polyurethane filling process, which is the next process. That is, in this process, the nonwoven fabric is impregnated in an aqueous polyvinyl alcohol solution having a concentration of 5 to 20%, the aqueous solution is 100% saturated in the nonwoven fabric, and the aqueous solution is squeezed and dried again to obtain a resin at the intersection of the fiber surface and the fiber. In this case, the resin binder to be used is selected from polyvinyl alcohol, carboxymethyl cellulose, and derivatives of starch or starch, and among these resin binders, it should be selected that can be easily dissolved and removed during the next de-homolysis process. .

The next step is to make the fibers ultra-fine and to fill the elastic polymer material. The two processes can be performed within the limits of the process, depending on the characteristics of the two types of fibrous polymer materials and the binder selected during the first process. The order of the processes is determined. At this time, the present invention adopts a method of filling the polyurethane and then filling the polyurethane first, and the above sea component among the polystyrene and polyethylene, polyester and polyamide which can be easily extracted by a solvent Each of them is easily eluted by impregnation with perchloroethylene, toluene, caustic soda or formic acid, followed by repeated squeezing. In addition, the elastic polymer material is selected from synthetic rubbers such as nitrile butadiene rubber or styrene butadiene rubber and polyurethane and its derivatives, polyvinyl chloride and polyamino acid resin, in the present invention, DMF soluble polyurethane elastomer The DMF solution of the polyurethane elastomer is used after copolymerizing polyester diol and polyether diol so as to have an average molecular weight of 100,000 or more, and then diluting with a solvent to adjust the viscosity. When the DMF solution of the polyurethane elastomer thus formed is impregnated with a nonwoven fabric, the polyurethane is solidified in the non-solvent system or the non-solvent and solvent mixture system of the polyurethane, and the polyvinyl alcohol, which is a filler, is removed. The characteristic flexible elasticity and drape property which it has is expressed, At this time, it is preferable to adjust the filling amount of polyurethane to 40 to 120% by solid content with respect to fiber weight.

Subsequently, a third step of buffing the surface of the fiber with sandpaper and performing dyeing processing produces a suede-like artificial leather having excellent lighting effect in which numerous microfine denier fibrils are present on the surface. The furnace is impregnated with a heat-reactive water-based polyurethane prepolymer as a fourth process, and thus dried and heat-treated as the final product still lacks resilience and low form stability. At this time, the isocyanate group at the end of the polyurethane prepolymer by the reaction of the ester or ether type polyol with the polyisocyanate group is blocked by sodium bicarbonate or the like to have storage stability, and there may be a slight difference depending on the blocking agent, but it is about 100 to 160 ° C. By heat treatment at the temperature of easily to be released, at the same time the isocyanate group at the end is easily crosslinked with the activated hydrogen in the adjacent polymer chain to form a three-dimensional network structure is excellent solvent resistance and elasticity. This is believed to be due to the densification of the structure of the wet impregnated polyurethane, which is somewhat embrittled during the extraction and dyeing of the sea component. In this case, the fourth step is particularly effective. In addition, when the softening agent and the water repellent agent are treated together during the fourth step, the wet processing-specific touch and high water repellency are simultaneously obtained.

On the other hand, the polyurethane prepolymer used in the present invention is a polyester polyol having a molecular weight of 500 to 5,000 containing an active hydrogen atom at the terminal, polyether polyol or polyester polyol is reacted with a polyisocyanate by a known method to the isocyanate at the terminal The polyisocyanate is selected from hexamethylene diisocyanate, 4, 4'-diphenylmethane diisocyanate or tolylene diisocyanate, and optionally ethylene glycol or 1, with polyisocyanate. Alcohols, such as 4-butane diol, and amines, such as ethylenediamine and hexamethylenediamine, may be applied together. The polyurethane prepolymer prepared in this way is easily blocked by reacting with an aqueous sodium bisulfite solution in a temperature range of 30 ° C. to 60 ° C. As the blocking agent, bisulfite, phenols or alcohols may be used. It is used by considering dissociation temperature and crosslinking reactivity according to heat treatment. Then, when the polyurethane prepolymer emulsion obtained as described above is added with hydrogen peroxide while appropriately diluted with water, an aqueous solution having good market stability is formed, and the filling amount of the polyurethane prepolymer is 1 to 20% based on the weight of the fiber. It is preferable that it is and it is good to process by a normal impregnation method at this time.

In addition, when the suede artificial leather manufactured by the above method is trimmed on the surface of the wool with sandpaper of about 320 #, it is possible to manufacture high-quality artificial leather which has excellent resilience, good dimensional stability, and wet touch. It will be possible.

In addition, according to the present invention, when the synthetic leather is filled with a non-woven fabric made of island-in-the-sea composite fiber, the physical properties of the island-in-the-sea composite fiber and polyurethane, which are the main raw materials, may be weakened during the ultrafine process or dyeing process. In particular, it has been found that the use of polyester or polyamide as sea component causes embrittlement of fibers and polyurethane during the ultrafine process and during the dyeing process when polyethylene terephthalate is used as the island component.

Therefore, in the present invention, after the dyeing process, a thermally reactive polyurethane prepolymer is added in the final step to crosslink the structure of the polyurethane, thereby improving durability of the solvent and improving the resilience of the nonwoven fabric.

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

Example 1

A staple fiber having a length of 51 mm having a fineness of 3 deniers is manufactured by using 60 parts of polyethylene terephthalate as a sea component and 40 parts of polystyrene as sea components. The degree of water content is 16 fibril / filament and the degree of fineness after removal of sea components is 0.1. It was denier. The fiber was carded with a roller carding machine and needle punched with needle 40 to produce a three-dimensional deadlock nonwoven fabric having a weight of 700 g / m 2 (first step).

In the next step, the nonwoven fabric was treated with an aqueous 10% polyvinyl alcohol solution to give 10% solids based on the weight of the fiber, followed by removal of polystyrene as a sea component using perchloroethylene, and the fiber was microfiberized. Impregnated and impregnated with DMF solution of urethane, it was coagulated in water, and polyvinyl alcohol, a filler, was removed from hot water to prepare a leather-like sheet (second step).

The sheet thus obtained was divided into two in the thickness direction, and the surface thereof was buffed with sandpaper to prepare a suede artificial leather having a weight of 300 g / m 2 and a thickness of about 0.8 mm, and dyed with a disperse dye in a liquid dyeing machine. 3 process).

The dyed sheet was impregnated with a water-based reactive polyurethane prepolymer using a polyether polyol, preliminarily dried, and then heat-treated at a temperature of 150 ° C. to give 5% of the solids by weight to the fiber weight (fourth step).

In this case, the method for producing a DMF solution of the polyurethane used in the second step is selected as polyol polycaprolactone diol having a molecular weight of 2,000, 4, 4'- diphenylmethane diisocinate as an organic isocyanate 60 After reacting at a temperature of 2 hours for 2 hours to form a polymer, a polymerization reaction was carried out by applying a chain extender such as ethylene glycol or 1,4-butanediol to obtain a DMF solution having a viscosity of 500% and a concentration of 30%. Polyurethane prepolymer used in the fourth step is an ether type polyol having a molecular weight of 2,000, hexamethyl diisocyanate and 1, 6-hexanediol are reacted at a temperature of 100 ℃ to make a polyurethane prepolymer and then diluted with dioxane The isocyanate group at the end was blocked with aqueous sodium bisulfite solution and emulsified with water to prepare a polyurethane prepolymer emulsion. The pH was adjusted to 6.5 and used.

Comparative Example 1

The same process as in Example 1 was carried out except that the step of treating the water-based thermoreactive polyurethane prepolymer as the fourth step was omitted.

Example 2

Nylon-660 parts as a island component and 40 parts of polyester as a sea component to produce a staple fiber having a length of 4 mm having a fineness of 4 denier, wherein the number of island components was 36Fibril / Fiment and the island-in-the-sea composite fiber was 18 pieces. After crimping at / inch, cut it to a certain length, squeeze it with a roller carding machine, and needle punch to prepare a three-dimensional deadlock nonwoven fabric with a weight of 300g / m2 and a thickness of 0.8mm, and then shrink it in hot water to reduce the apparent density of the nonwoven fabric. (First process).

The nonwoven fabric was wet-processed with a polyurethane elastomer of polytetramethylene ether glycol to give about 40% of the fiber weight, and microfibers having 0.04 denier fineness of fibrils have a fineness by dissolving and eliminating seaweed polyester in alkali. Was formed (second step).

The surface of the sheet thus formed is buffed with 180 mesh sandpaper and dyed with acid dyes or metal complex dyes to form suede artificial leather (3rd step). It is also possible to develop a color, and the 15% emulsion of polyethylene glycol-based polyurethane prepolymer is diluted with water to impregnate the sheet with a catalyst. At this time, the polyurethane-based softener is also treated simultaneously and dried at a temperature of 120 ° C. and then 150 ° C. The mixture was heat treated at a temperature for 1 minute to crosslink the terminal isocyanate group (fourth step). At this time, the amount of the polyurethane prepolymer imparted was 10% as solids based on the weight of the fiber.

Comparative Example 2

The same process as in Example 2 was carried out and water-repellent except that the step of treating with a polyethylene glycol-based polyurethane prepolymer as a fourth step was omitted.

The physical properties of the artificial leather prepared according to Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 below.

TABLE 1

As can be seen from Table 1 above, the artificial leathers prepared in Examples 1 and 2 according to the present invention are excellent in elasticity, give a wet touch, and have high water repellency.

That is, according to the present invention, not only the elasticity of the artificial leather can be improved by wet polyurethane impregnation processing, but also the soft touch is expressed, and the secondary processing of the post-processing with dry polyurethane is excellent in durability and form stability and anti-pilling property. This improved suede-like artificial leather will be able to manufacture, and these products can be used in a wide variety of applications, from clothing to interior materials and sundries.

Claims (5)

In the method of manufacturing suede artificial leather, a first step of producing a non-woven fabric made of a composite fiber capable of microfiber, a second step of miniaturizing the fiber and imparting an elastic polymer material, buffing and dyeing the fiber surface A method of producing suede-like artificial leather with excellent resilience and feel, characterized in that the flexibility, resilience, and feel of artificial leather are excellent through a third step of applying a three-step and heat-reacting polyurethane prepolymer. The method of claim 1, wherein the elastic polymer material to be imparted during the second process is selected from synthetic rubbers such as nitrile butadiene rubber and styrene butadiene rubber and dimethylformamide soluble linear polyurethane having an average molecular weight of 100,000 or more. 3. The method according to claim 2, wherein the amount of the elastic polymer material is 40 to 120% by weight based on the weight of the fiber after removing the sea component. The method according to claim 1, wherein the thermally reactive polyurethane copolymer in the fourth step is an aqueous emulsion formed by blocking isocyanate groups contained at its ends with bisulfite. 5. The method according to claim 4, wherein the amount of the thermally reactive polyurethane prepolymer is 1 to 20% by weight based on the weight of the fiber.