KR19990075812A - Manufacturing method of synthetic leather using water dispersible polyurethane resin - Google Patents

Abstract

The present invention relates to a synthetic leather manufacturing method using a water-dispersible polyurethane (Waterborne Polyurethane), in a method for producing a synthetic leather by forming an adhesive layer and a silver layer on the fabric, a polyurethane resin mixture for a silver layer and a polyurethane resin for an adhesive layer The water-dispersible polyurethane resin is included in the formulation, and the water-dispersible polyurethane resin is used to reduce the harmfulness and environmental problems of oil-based polyurethane resins used in manufacturing conventional synthetic leather. It relates to a method for producing synthetic leather.

Description

Manufacturing Method of Synthetic Leather Using Waterborne Polyurethane Resin

The present invention relates to a synthetic leather manufacturing method using water-dispersible polyurethane (Waterborne Polyurethane), more specifically, to reduce the harmfulness of the human body and environmental problems of the oil-based polyurethane resin used when manufacturing synthetic leather It relates to a synthetic leather production method using a water-dispersible polyurethane resin.

In general, the polyurethane resin used in the manufacture of synthetic leather is polymerized by reacting polyol (POLYOL) with diisocyanate (DIISOCYANATE) and chain extender (CHAIN EXTENDER) using dimethylformamide as a solvent.

Polyurethane resin polymerization is carried out by solution polymerization of polyols, diisocyanates and chain extenders with dimethylformamide as a solvent. Ester polyols and ether polyols are mainly used for polyols, and MDI is used for diisocyanates. Diphenylmethan diisocyanate and TDI (toluene didisocyanate) are mainly used, and diols such as 1,4-butane diol and ethylene glycol are mainly used as chain extenders. Dimethylformamide used as the solvent is used for viscosity control and reaction control in the polymerization process.

In addition, the polymerized polyurethane resin is used as the impregnation resin and coating resin of the synthetic leather, the manufacturing process of the synthetic leather using the same is as follows.

The base material is produced by impregnating or coating various fabrics in a compounding solution containing a polyurethane resin, a surfactant, a pigment, and dimethylformamide in an appropriate ratio, and processing a pattern, polishing, or printing. Synthetic leather is manufactured through the process.

Dry synthetic leather manufacturing method is the most widely used method of manufacturing synthetic leather, and the manufacturing process is slightly different depending on the use of the finished product. To explain this in more detail, first, a release paper having strong heat resistance, high tensile strength, and good peelability is coated with a silver layer, which is a surface of synthetic leather, using a compensator, dried, and then coated with an adhesive resin on the silver layer. Combined with the fabric and wound up, it is matured to complete drying and curing, and then the release paper is peeled off in a peeler to produce a finished product.

As described above, when polymerizing polyurethane resin or preparing synthetic leather with polyurethane resin, dimethylformamide is used in a considerable amount. About 50 to 75 parts by weight of dimethylformamide is used during polyurethane polymerization, and synthetic leather is manufactured. When used, about 25 to 80 parts by weight is used. As a result, dimethylformamide is directly or indirectly harmful to workers working for polyurethane resin companies or synthetic leather manufacturing companies, causing environmental problems.

For example, in the case of a synthetic leather manufacturer, a considerable amount of dimethylformamide is included when handling a blended solution of a polyurethane resin, and a local exhaust system is provided to discharge dimethylformamide to the outside, and the worker is put into dimethylformamide. Work should be done after wearing a gas mask and rubber gloves to prevent exposure.

Accordingly, the worker feels inconvenient during the work and the work efficiency is lowered. In addition, even if a local exhaust device is installed, since dimethylformamide remains in the working space in small amounts, there is a problem that dimethylformamide accumulates in the worker's body through long periods of work, affecting the liver or skin.

In order to solve this problem, a method of applying a water-dispersible polyurethane resin to artificial leather instead of an oil-based polyurethane resin has been devised, but since the oil-based polyurethane resin is polymerized in an organic solvent, chain extension is easy and molecular weight can be controlled. While excellent physical properties appear, the water-dispersible polyurethane resin forms micelles in water and expands the chain therein, thus limiting the molecular weight increase and the raw materials used are limited due to hydrolysis. It could not be used because it did not satisfy the mechanical properties.

The present invention is to solve the above problems, an object of the present invention is to provide an artificial leather manufacturing method using a water-dispersible polyurethane that can satisfy the mechanical properties required by artificial leather.

Artificial leather manufacturing method using the water-dispersible polyurethane resin of the present invention for achieving the above object is characterized in that the water-dispersible polyurethane resin is included in the polyurethane resin formulation for the silver layer and the polyurethane resin mixture for the adhesive layer. It is.

The addition of a curing agent to the polyurethane resin mixture for the silver layer and the adhesive layer is preferred in view of the physical properties of the synthetic leather which can be produced, and more preferably a fluorine-based compound having a structure of -CF2-CF2-. It is most preferable to use the water-dispersible polyurethane resin which mixed 2 or more types from which the initial elastic modulus differs.

Hereinafter, the configuration and operation of the present invention will be described in detail.

As described above, the present invention relates to a method of manufacturing synthetic leather using a water-dispersible polyurethane that does not cause human harm and environmental problems in the manufacturing process, and to a method of manufacturing synthetic leather by forming an adhesive layer and a silver layer on a fabric. The water dispersible polyurethane resin was contained in the polyurethane resin mixture for silver layers and the polyurethane resin mixture for adhesive layers.

The addition of a curing agent to the polyurethane resin mixture for the silver layer and the adhesive layer is preferred in view of the physical properties of the synthetic leather which can be produced, and more preferably a fluorine-based compound having a structure of -CF2-CF2-. It is most preferable to use the water-dispersible polyurethane resin which mixed 2 or more types from which the initial elastic modulus differs.

In the synthetic leather manufacturing method, the water-dispersible polyurethane resin has a very low drying rate and poor intermolecular force and flowability, compared to the conventional oil-based polyurethane resin, so as to compensate for this, the drying temperature is increased (120-150 ° C.). Is preferably used).

In addition, the bonding method between the silver layer and the fabric, that is, the fabric, is made through the adhesive layer. When the adhesive resin is applied and then directly bonded, the adhesion is hindered by water, which is the main solvent of the water-dispersible polyurethane resin, and thus the adhesive layer is semi-dried. Semi-drying bonding methods that adhere and then dry completely are preferred.

In addition, since the water-dispersible polyurethane resin has its own viscosity varying from 10 to 8,000, it is preferable to use a thickener, and bubbles generated during stirring are removed using a defoamer.

The curing agent added to the polyurethane resin mixture for the silver layer and the adhesive layer increases the wear strength and hydrolysis resistance when added to the silver layer, and when added to the adhesive layer, serves to compensate the adhesion of the water-dispersible polyurethane resin. . Preferred for use as a curing agent include a water dispersible crosslinking agent containing an excess of diisocyanate. It should be noted that when using this crosslinking agent, if the drying temperature exceeds 120 ° C, it is hardened by side reactions, so it is preferable to make the operation between 70-120 ° C.

In addition, by using the fluorine-based compound in the polyurethane resin mixture for the silver layer, it plays a role of improving wear strength without affecting other physical properties, and has weak flow between molecules, which is a disadvantage of the water-dispersible polyurethane resin, and has good flowability. To prevent surface cracking. When using it, it should be sufficiently stirred to prevent adverse effects on the surface smoothness.

In addition, when the water-dispersible polyurethane resin is a mixture of two or more kinds having different initial modulus, the softness and surface feel of the resin having a low initial modulus can be utilized, and the wear strength of the resin having a high initial modulus is high. It can be saved.

Hereinafter will be described in more detail through embodiments of the present invention.

Example 1. Manufacture of 1.3mm Dry Synthetic Leather

The release paper is supplied from a compensator, and the silver layer is coated with a silver PU mixture in an amount of 100-140 g / LM, and the silver layer is dried at 120-150 ° C., and then the silver PU mixture is further dried. The silver layer was coated in an amount of 140 g / LM and the silver layer was dried at 120-150 ° C. Subsequently, the adhesive PU mixture was coated with an adhesive resin in an amount of 140-190 g / LM on the two silver layer surfaces, and the adhesive resin was semi-dried at 80-120 ° C. The fabric was bonded to the semi-dry adhesive layer and then dried at 110-130 ° C. It was wound up, aged at 60-100 ° C. for 24 hours, and then the release paper was removed to make a finished product.

The main raw and subsidiary materials used at this time are as follows.

Fabric: Weight 460g / m2, Thickness 1.25mm (nylon = 100)

Silver PU formulation:

Water Dispersible PU Resin (NV = 30-60) 100

Surfactant 1.12-6.2

Thickener 2-10

Water Dispersible Pigment 15-20

Adhesive PU Blending Solution:

Water Dispersible PU Resin (NV = 30-60) 100

Surfactant 1.07-6.0

Thickener 2-10

Herein, the silver layer and the adhesive PU compounding solution show a weight ratio when the weight of the water dispersible PU resin is 100.

Example 2. Preparation of 1.0mm Dry Synthetic Leather

Fabric was prepared in the same manner as in Example 1 using a weight of 327 g / m 2, a thickness of 0.95 mm (nylon = 100) microfiber.

Example 3. Preparation of 1.5mm Dry Synthetic Leather

Fabric was prepared in the same manner as in Example 1 using a weight of 518g / m2, a thickness of 1.45mm (nylon = 100) microfiber.

Example 4-6

Example 4 uses the fabric of Example 1, Example 5 uses the fabric of Example 2, Example 6 uses the fabric of Example 3, and the PU layer solution for the silver layer and the PU mixture solution for adhesion are The synthetic leather of 1.3mm, 1.0mm, 1.5mm was produced in the manufacturing process of Example 1 as follows, except that the drying temperature was different, but the silver layer drying temperature was 70-130 ° C and the adhesive layer semi-drying temperature was 70 -120 degreeC and the adhesion layer drying temperature were 70-120 degreeC.

Silver PU formulation:

Water Dispersible PU Resin (NV = 30-60) 100

Surfactant 2.0-3.2

Hardener 5-10

Dispersant 5-10

Thickener 2-10

Water Dispersible Pigment 15-20

Adhesive PU Blending Solution:

Water Dispersible PU Resin (NV = 30-60) 100

Surfactant 2-3

Hardener 5-10

Dispersant 5-10

Thickener 2-10

Example 7-9

Example 7 uses the fabric of Example 1, Example 8 uses the fabric of Example 2, and Example 9 uses the fabric of Example 3, and the PU mixture solution for the silver layer and the PU mixture solution for adhesion are As described below, a dry synthetic leather of 1.3 mm, 1.0 mm, and 1.5 mm was prepared in the manufacturing process of Example 4, respectively.

Silver PU formulation:

Water Dispersible PU Resin (NV = 30-60) 100

Surfactant 2.0-3.2

Hardener 5-10

Dispersant 5-10

Fluorine Compound 1-5

Thickener 2-10

Water Dispersible Pigment 15-20

Adhesive PU Blending Solution:

Water Dispersible PU Resin (NV = 30-60) 100

Surfactant 2-3

Hardener 5-10

Dispersant 5-10

Thickener 2-10

Example 10-12

Example 10 uses the fabric of Example 1, Example 11 uses the fabric of Example 2, Example 12 uses the fabric of Example 3, and the PU layer solution for bonding and the PU mixture solution for bonding are As described below, a dry synthetic leather of 1.3 mm, 1.0 mm, and 1.5 mm was prepared in the manufacturing process of Example 4, respectively.

Silver PU formulation:

Water Dispersible PU Resin (NV = 30-60, Initial Modulus 30-40) 100

Water Dispersible PU Resin (NV = 30-60, Initial Modulus 70-90) 100

Surfactant 2.0-3.2

Hardener 5-10

Dispersant 5-10

Fluorine Compound 1-5

Thickener 2-10

Water Dispersible Pigment 15-20

Adhesive PU Blending Solution:

Water Dispersible PU Resin (NV = 30-60) 100

Surfactant 2-3

Hardener 5-10

Dispersant 5-10

Thickener 2-10

Example 1-3 is an example of a method for producing a synthetic leather by applying only a minimal additive to the blend, Example 4-6 is a case of adding a curing agent, Example 7-9 is a fluorine-based compound In the case of addition, Example 10-12 is an example of the case where a polyurethane resin having a different initial modulus of elasticity is blended and used.

The synthetic leather thus prepared was subjected to abrasion strength, adhesive strength and hydrolysis test. The results are shown in Table 1 below. At this time, the wear strength test was performed under the conditions of STOLL 1POUND, 320J SANDPAPER / 25 ℃ based on ASTM D-3886 and TABER 1000g, H-22 / 25 ℃ based on ASTM D-3884 conditions were shown, The hydrolysis test showed visual inspection results after 24 hours at 10% NaOH / 30 ° C.

Item Example 1-3 Example 4-6 Example 7-9 Example 10-12 Wear strength STOLL Less than 300 times 350 times 400 times 500 TABER 500 or more times 700 times 700 times 800 Adhesive Strength (kg / cm) 2-3 4-5 4-5 4-5 Hydrolysis Experiment Pass Pass Pass Pass

As shown in Table 1, the use of a water dispersible polyurethane resin and a curing agent rather than only a surfactant and a thickener as an additive, the addition of a fluorine-based compound component further, a polyurethane resin having a different initial modulus It can be seen that using the blended to have excellent mechanical properties.

Synthetic leather manufacturing method using the water-dispersible polyurethane resin of the present invention, it is possible to apply a water-dispersible polyurethane resin that could not be used in the conventional mechanical properties problems in the synthetic leather manufacturing process, thereby causing a harmful or environmental The contamination can be reduced, and furthermore, by appropriately adjusting the composition of the silver PU mixture, it is possible to manufacture synthetic leather having satisfactory mechanical properties.

Claims (4)

A method of producing a synthetic leather by forming an adhesive layer and a silver layer on a fabric, wherein the water-dispersible polyurethane comprising a water-dispersible polyurethane resin in a polyurethane resin mixture for a silver layer and a polyurethane resin mixture for an adhesive layer Synthetic leather manufacturing method using. The synthetic leather production method using a water dispersible polyurethane according to claim 1, wherein a curing agent is added to the polyurethane resin mixture for the silver layer and the adhesive layer. The method of claim 1, wherein a fluorine-based compound having a structure of -CF2-CF2- is added to the polyurethane resin mixture for the silver layer and the adhesive layer. The method of claim 1, wherein the water-dispersible polyurethane resin is a synthetic leather manufacturing method using a water-dispersible polyurethane, characterized in that the mixture of two or more different initial modulus.