KR20220140953A - Method of manufacturing artificial leather using water-borne polyurethane resin for car interiors - Google Patents

Abstract

The present invention uses a resin impregnating liquid containing water-borne liquids of non-ionic-based water-borne polyurethane resins, non-ionic surfactant and heat-sensitive coagulant as a fiber base layer (F) by impregnating the resin impregnating liquid into fiber fabric such as non-woven fabric and drying the same by hot air. The artificial leather for eco-friendly car interior materials is manufactured as follows: coating and drying negative ion-based polyurethane water-borne liquid on release paper separately to form a surface film layer (S); coating and drying two-liquid type solventless polyurethane adhesive solution on the surface film layer (S) to form a solventless adhesive layer (A); laminating, drying, and aging the fiber base layer (F) on the solventless adhesive layer (A) by a laminating method; and peeling the release paper from the surface film layer (S) and surface-treating the same. The fiber base layer (F) is not like paper by evenly distributing non-ionic-based water-borne polyurethane resins without migrating into a fabric surface and has excellent forming processibility because minute wrinkles are formed when folded. The present invention uses non-ionic-based water-borne polyurethane resins as a skin layer and employs solventless polyurethane resins as an adhesive layer, such that organic solvent harmful to a human body does not remain, thereby being eco-friendly, and surface durability, water resistance and weather-proof are excellent, thereby being particularly useful as a car interior material.

Description

Method of manufacturing artificial leather using water-borne polyurethane resin for car interiors

The present invention is characterized in that in the process of manufacturing polyurethane artificial leather for automobile interior materials, a non-ionic water-dispersed polyurethane resin is impregnated into a non-woven fabric as a fiber base layer, and anionic polyurethane water is used as a surface film layer. The dispersion is coated and dried, and a two-component solvent-free polyurethane adhesive is used as the adhesive layer, so the content of volatile organic substances (VOC) remaining in the product is dramatically reduced compared to the conventional solvent-type artificial leather, while physical properties and molding processability It relates to a manufacturing method of this excellent artificial leather for interior materials of automobiles.

In particular, the present invention improves the method of impregnating and coating a nonwoven fabric with a conventional solvent-type polyurethane resin by a wet processing method, and by impregnating the nonwoven fabric with an aqueous polyurethane resin by a dry method, dimethylformamide, an organic solvent harmful to the human body, is not used. It relates to a new method for manufacturing artificial leather that does not need to be and the work process is simplified, thereby reducing the cost.

More specifically, when the non-ionic water-dispersed polyurethane resin is impregnated into the non-woven fabric and dried, the water-dispersed polyurethane resin is not evenly distributed inside the non-woven fabric and is a novel heat-sensitive method that prevents migration to the surface. An object of the present invention is to provide a manufacturing method for improving wrinkles and bending of the impregnated nonwoven fabric by applying a coagulation method.

The silver-faced polyurethane (PU) artificial leather usually has a three-layer structure including a surface skin layer (also called a surface film layer), an adhesive layer, and a fiber base layer. In the industry, solvent-based polyurethane resins have been used for a long time in the impregnation and coating process of the fiber base layer, the surface skin layer coating process, and the adhesive layer coating process. Solvent-type polyurethane resins use dimethylformamide (DMF) or methyl ethyl ketone (MEK) As a resin dissolved in an organic solvent such as an organic solvent, it has good film forming processability and exhibits excellent physical properties such as water resistance, light resistance, heat resistance, and abrasion strength when applied to artificial leather. A large amount of volatile organic substances remain in the product, and process improvement has been a long-standing task in the industry.

As a method to replace solvent-type polyurethane resin, attempts to apply water-dispersible polyurethane (hereinafter abbreviated as "PUD") or non-solvent PU resin have continued, and in recent years, There are cases where the acidic polyurethane is applied for a surface skin layer by improving the water resistance , and a number of methods of applying solvent-free polyurethane as a skin layer or an adhesive layer have been reported.

However, in the process of impregnating a polyurethane resin into a nonwoven fabric, knitted fabric, or warp knitted fabric used as a fiber base layer, a method of impregnating a solvent-type polyurethane resin with a wet method and solidifying and washing with water is still used. For example, resin impregnation processing of needle punching nonwoven fabric, which is often used for car seats, is still applying solvent-type polyurethane as a wet method.

Recently, studies to replace the solvent-type resin wet impregnation method of the fiber base layer with an eco-friendly, water-dispersible polyurethane (PUD) dry method have been actively conducted. That is, when the water-dispersible polyurethane resin is impregnated into the non-woven fabric and dried, the polyurethane resin is not evenly distributed inside the non-woven fabric and prevents migration to the surface, thereby improving the large wrinkles and bending of the impregnated non-woven fabric. A number of manufacturing methods have been reported.

As an example of application of water-dispersible polyurethane, Republic of Korea Patent No. 10-0621300 discloses that the nonwoven fabric is pretreated with a silicone-based flexible water repellent before impregnating the water-dispersible polyurethane resin to prevent adhesion of fibers and resins, followed by inorganic to water-dispersible PUD having a specific modulus of elasticity. A method for producing a leather-like sheet having excellent flexibility by thermal coagulation by adding salts and nonionic surfactants is presented. However, this method requires a separate pretreatment process and has disadvantages of wet heat solidification under hot water or steam of 70° C. or higher, so that commercial use is very limited.

As an improved patent with a simpler process, Korean Patent Laid-Open Patent Publication No. 10-2016-0027079 discloses that non-ionic emulsifier having an oxyethylene group and inorganic salts are added to anionic water-dispersed PUD, impregnated with nonwoven fabric, and dried with hot air to provide excellent flexibility and rebound elasticity. A method for manufacturing an upper sheet is presented. However, the lack of compatibility with anionic water-dispersed PUD remains a problem to be solved when a flame retardant is added for application to vehicle interior materials requiring flame retardancy.

On the other hand, in International Publication No. WO2015-115290, an anionic PUD resin having a hydrophilic group is synthesized, a crosslinking agent and inorganic salts are added thereto, impregnated with a nonwoven fabric, and a sheet with good wrinkle properties through successive wet heat drying, dry heat drying and high temperature heat treatment processes. A method for manufacturing a product is presented. However, the above method still requires a process of pre-treating the polyvinyl alcohol aqueous dispersion before impregnating the nonwoven fabric with the aqueous dispersion PUD blending solution and removing it in hot water later, so the process is still complicated.

The researchers synthesized a novel nonionic water-dispersible polyurethane resin capable of thermal coagulation, impregnated it with a nonwoven fabric, and dried it with hot air to evenly distribute the resin inside the nonwoven fabric without migration of the resin. It was possible to devise a method for making a fiber base layer with good wrinkle properties. In addition, in the present invention, by utilizing the prior patent of the present inventors, Republic of Korea Patent No. 10-1804219, it was possible to complete the artificial leather for the interior material of an eco-friendly vehicle. That is, as a dry skin layer, an anionic polyurethane aqueous dispersion is applied on a release paper and dried to form a surface film layer, and a two-component solvent-free polyurethane adhesive solution is applied and dried on the surface film layer to form a solvent-free adhesive layer, , a method of laminating a fiber base layer on the adhesive layer was applied.

An object of the present invention is to provide a method of manufacturing an eco-friendly artificial leather in which volatile organic substances such as dimethylformamide are hardly left in the final product by purifying the work process by fundamentally excluding the use of organic solvents.

Another object of the present invention is to provide a method of manufacturing artificial leather useful as a material for interior materials for automobiles with excellent moldability by reducing wrinkling and wrinkling by evenly distributing resin in the fiber base layer while being eco-friendly because no harmful substances remain will be.

For this purpose, in the present invention, a nonionic water-dispersed polyurethane resin is used for impregnating the fiber base layer of artificial leather, and a polyurethane resin excluding solvent is used for the skin layer and the adhesive layer. It is intended to present a method for manufacturing leather. In particular, specific implementation of the method for synthesizing and impregnating water-dispersed polyurethane resins with excellent compatibility with flame retardants and improving the migration phenomenon of the resin, which has been pointed out as a problem when using water-dispersed polyurethane resins for impregnation of fiber base layers Let me explain by way of example.

In order to achieve the above object, in the present invention, a resin impregnating solution containing a nonionic water-dispersed polyurethane resin, a nonionic surfactant and a thermal coagulant is impregnated into a fiber fabric such as a nonwoven fabric and dried with hot air to form a fiber base layer ( F) is used. Separately, anionic water-dispersed polyurethane resin is applied and dried on a release paper to form a surface film layer (S), and a two-component solvent-free polyurethane adhesive solution is applied and dried on the surface film layer (S) to form a solvent-free adhesive layer ( A) was formed, and the fiber base layer (F) prepared above on the solvent-free adhesive layer (A) was laminated, dried and aged by a laminating method, and then the release paper was peeled from the surface film layer (S) and then surface treated. The artificial leather for the interior material of the eco-friendly vehicle is manufactured.

Here, the nonionic water-dispersed polyurethane resin is a diol component consisting of polytetramethylene glycol (PTMEG), polypropylene glycol (PPG) and polyoxyethylene propylene glycol and alicyclic diisocyanate or aliphatic diisocyanate, preferably It is synthesized by reacting isophorone diisocyanate. After mixing a nonionic surfactant and an inorganic salt thermal coagulant with the synthesized aqueous dispersion of about 35% solid content, add a flame retardant and water-based pigment to the textile fabric, and dry it under hot air for a sense of fulfillment and fine wrinkles when folded. A fiber base layer is prepared.

On the other hand, as for the aqueous dispersion of anionic polyurethane used for skin, polycarbonate-based or polycarbonate and polyether copolymer-based resins are suitable for securing excellent physical properties for automobile interior materials. After mixing the additives to prepare a compounding solution, the prepared compounding solution is applied on a release paper and dried to form a surface film layer (S).

In addition, the two-component solvent-free adhesive of the present invention is based on a hydroxyl-terminated urethane prepolymer and a crosslinking agent such as modified diphenylmethane diisocyanate (MDI), which is liquid at room temperature, is separated from each other. Dispenser installed at the tip of the coater After being supplied to the mixture, it is coated on the surface film layer (S) at the same time as it is mixed and cured by heating to be laminated with the fiber base layer. At this time, the main tank contains additives such as a bromine-based or phosphorus-based flame retardant and a leveling agent.

The three types of polyurethane resin formulation prepared above were applied as a fiber base layer, a skin layer, and an adhesive layer, respectively, to prepare artificial leather for automobile interior materials as follows. That is, the fiber base layer is prepared by impregnating and drying the aqueous dispersion of the nonionic water-dispersed polyurethane resin in the textile fabric. Next, the anionic polyurethane aqueous dispersion is coated on the release paper and dried to form a surface film layer, coated with a two-component solvent-free adhesive, and semi-dried at 130 to 140° C., and then laminated with the fiber base layer After aging for more than 48 hours in an aging room at 60-70°C, peeling the release paper and performing the necessary post-processing ensures excellent wrinkle properties, adhesive strength, heat resistance, and hydrolysis resistance at a level that can be used for vehicle interior materials. .

In the present invention, a water-dispersed polyurethane resin containing no organic solvent is applied as a surface film layer, and a two-component solvent-free adhesive is used to laminate it with a fiber base layer impregnated with water-dispersible polyurethane resin, thereby creating an eco-friendly, three-layer structure. The production of leather was possible. In addition, the present invention has an effect of contributing to the cleaning of the work process by using a water-dispersible polyurethane resin and a solvent-free polyurethane adhesive.

The present invention mixes a water-dispersed polyurethane resin with a nonionic surfactant and a thermal coagulant of inorganic salts and impregnates the textile fabric, so that the resin is evenly distributed on the textile fabric after hot air drying, giving a paper-like feeling. Because it is flexible and has excellent physical properties, it is possible to improve workability and production efficiency while simplifying the conventional complicated processing method.

Therefore, the artificial leather of the present invention has excellent wrinkle properties, is flexible, has good moldability, and has very little volatile organic substances (VOCs) such as dimethylformamide (DMF) remaining in the product. useful.

1 is an optical micrograph of a cross-section of a nonwoven fabric impregnated with an aqueous dispersion polyurethane resin blending solution of Example 1 of the present invention.
Figure 2 is an electron micrograph of the cross-section of the nonwoven fabric impregnated with the aqueous dispersion polyurethane resin blending solution of Example 1 of the present invention.
Figure 3 is an optical micrograph of a cross-section of the nonwoven fabric impregnated with the aqueous dispersion polyurethane resin blending solution of Comparative Example 3 of the present invention.
4 is an electron microscope photograph of a cross-section of a nonwoven fabric impregnated with an aqueous dispersion polyurethane resin blending solution of Comparative Example 3 of the present invention.
5 is an electron micrograph of the three-layer structure artificial leather prepared in Example 1 of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The manufacturing method of the artificial leather for an eco-friendly vehicle interior material according to the present invention comprises the steps of (i) impregnating a textile fabric with an aqueous dispersion of a nonionic water-dispersed polyurethane resin and drying it to form a textile base layer (F); (ii) forming a surface film layer (S) by applying and drying an anionic polyurethane aqueous dispersion on a release paper; (iii) forming a solvent-free adhesive layer (A) by applying and drying a two-component solvent-free polyurethane adhesive solution on the surface film layer (S); and (iv) laminating, drying and aging the fiber base layer (F) on the solvent-free adhesive layer (A) by a laminating method, and then peeling the release paper from the surface film layer (S) and then surface-treating; do.

In addition, the manufacturing method of the artificial leather for an eco-friendly vehicle interior material according to the present invention further comprises a process of mixing a nonionic surfactant, an aqueous thermal coagulant of inorganic salts, a flame retardant and an aqueous pigment with an aqueous dispersion of a nonionic water-dispersed polyurethane resin. include In addition, the method further includes a step of mixing additives such as a thickener, an anti-aggregation agent, a crosslinking agent and an aqueous pigment to the aqueous anionic polyurethane dispersion before applying the aqueous dispersion of anionic polyurethane on the release paper. In addition, the two-component solvent-free adhesive solution further includes a flame retardant in addition to the main agent, a crosslinking agent, and a catalyst.

The present invention is a nonionic surfactant compared to 100 parts by weight of the aqueous dispersion of the nonionic water-dispersed polyurethane resin before impregnating the textile fabric with the aqueous dispersion of the non-ionic water-dispersed polyurethane resin. ether) 1 to 5 parts by weight, 5 to 15 parts by weight of inorganic salts as a heat-sensitive coagulant, 10 to 30 parts by weight of a bromine-based or phosphorus-based flame retardant, and 100 to 300 parts by weight of water as a viscosity modifier are mixed and stirred to prepare a blending solution, It includes a manufacturing method of forming the fiber base layer (F) by controlling the amount of impregnation through a mangle after impregnating the blending solution into the fiber fabric and drying with hot air at 100 to 120° C. in a tenter.

In addition, the present invention is a nonionic water-dispersible polyurethane resin impregnated into the textile fabric is a diol component consisting of polytetramethylene glycol (PTMG), polypropylene glycol (PPG) and polyoxyethylene propylene glycol, alicyclic diisocyanate and aliphatic It is characterized in that it is prepared by reacting one kind of diisocyanate component selected from diisocyanate.

At this time, it is preferable to adjust the molar ratio of polytetramethylene glycol (PTMEG) and polypropylene glycol (PPG) to 60-80:40-20 when synthesizing the nonionic water-dispersed polyurethane resin.

First, the process of synthesizing the nonionic water-dispersed polyurethane resin to be impregnated into the textile fabric will be described.

Conventionally, anionic water-dispersed polyurethane resins are often applied as polyurethane resins impregnated into textile fabrics when manufacturing artificial leather, but it was confirmed that it is not suitable for flame-retardant type artificial leather that requires additional addition of a flame retardant. For example, according to a conventional method, 0.7 mol of polytetramethylene glycol (PTMG), 0.3 mol of polypropylene glycol (PPG), and 0.58 mol of dimethylolpropionic acid (DMPA) as an ionic diol are used as a polyol component, and isophorone diisocyanate ( IPDI) after reacting with 2.2 moles, neutralizing with triethyleneamine (TEA) to synthesize an aqueous dispersion of anionic polyurethane having a solid content of 35% and a 100% modulus of 17 kg/cm 2 As a result of checking, shocking occurred with phosphorus (P)-based and bromine (Br)-based flame retardants, and it was denatured like a gel, making it impossible to apply. This was presumed to be because the ion substitution reaction occurred between the carboxyl anion group (COO-NR3+) of the water-dispersed polyurethane main chain and the metal ion (Br+, P+) of the flame retardant, thereby degrading the stability of the resin.

In order to solve this problem, the present inventors synthesized a nonionic water-dispersed polyurethane resin as follows. Specifically, by reacting a diol component consisting of polytetramethylene glycol (PTMEG), polypropylene glycol (PPG) and polyoxyethylene propylene glycol with one diisocyanate component selected from alicyclic diisocyanate and aliphatic diisocyanate, nonionic water A dispersed polyurethane resin was prepared. Polyoxyethylene-based polyol is used as a nonionic hydrophilic polyol and polytetramethylene glycol (PTMEG) and polypropylene glycol (PPG) are applied in a ratio of 70:30 to synthesize a soft nonionic water-dispersed polyurethane resin to improve mechanical properties. It was measured and confirmed whether it was suitable as a resin for impregnation. As a result of impregnating the non-ionic water-dispersible polyurethane resin into the nonwoven fabric, as expected, aggregation with the flame retardant did not occur, a soft film could be formed, and the non-woven fabric had a soft handle and was suitable for impregnation.

That is, an addition reaction is performed with a diol component consisting of polytetramethylene glycol, polypropylene glycol, and polyoxyethylene propylene glycol and a diisocyanate such as isophorone diisocyanate at 80 to 100 ° C. for 3 to 5 hours, and distilled water and It is prepared by carrying out stirring and stabilization together. At this time, when the molar ratio of polytetramethylene glycol (PTMG): polypropylene glycol (PPG) is adjusted to 60-80: 40-20, the touch of the synthesized resin is suitable for impregnation, and the molar ratio of polypropylene glycol (PPG) is If it exceeds 40%, some stickiness may occur, and if it is less than 20%, the touch of the impregnated cloth may become slightly hard. It is preferable to adjust the molar ratio of NCO (diisocyanate): OH (polyol) to a ratio of 1.2 to 1.6: 1 in order to secure a suitable molecular weight.

As an embodiment of the present invention for preparing a nonionic water-dispersed polyurethane resin aqueous dispersion, as one synthesis example of the present invention, 0.7 moles of polytetramethylene glycol (PTMG) having a molecular weight of 2,000, and polypropylene glycol (PPG) having a molecular weight of 2,000 0.3 moles, polyoxyethylene propylene glycol 0.43 moles, and 1.98 moles of isophorone diisocyanate (IPDI) were added to the reaction tank and reacted at 90° C. for 4 hours to confirm that the remaining isocyanate is at a level of 1.5 wt %, and a small amount of acetone and antioxidants are added. After stirring for 30 minutes, the mixture was added dropwise to a dispersion tank filled with distilled water while stirring to prepare an aqueous dispersion having a solid content of 35% and a viscosity of 80 cps.

Next, the process of forming the fiber base layer (F) by impregnating the aqueous dispersion of the nonionic water-dispersed polyurethane resin prepared as described above in the fiber cloth and drying will be described.

In the case of water-dispersible resin, when it dries after impregnation, it dries from the surface side, and migration of the resin occurs. It is difficult to use and in order to prevent such migration, a method of using the cloud point of a nonionic surfactant and thermal coagulation together was devised. Nonionic surfactants have their own cloud point, and the cloud point is dissolved in a compounded state in the hydrophilic group of the surfactant. When the temperature rises, the solubility decreases, and when the temperature rises above a certain temperature, the transparent solution is suspended. When about 10 g of water-dispersible polyurethane (PUD) is immersed in a constant-temperature hot water bath and the temperature is raised while stirring slowly, the temperature at which fluidity is lost and gelled is called thermal gelation temperature, and the water-dispersible polyurethane (PUD) of the present invention ), a fatty alcohol polyglycol ether-based nonionic surfactant with a cloud point between 60 and 70°C and an HLB value of 15 or more, which is highly hydrophilic, was applied. In order to increase the migration prevention effect, a thermal coagulation method was applied at the same time to reduce the dispersion stability of the resin at a specific temperature by adding an appropriate amount of a thermal coagulant of inorganic salts such as sodium chloride and calcium chloride to the water-dispersible polyurethane (PUD) resin to coagulate it.

The anti-migration effect of the nonionic surfactant and the thermal coagulant can be confirmed in FIGS. 1 and 2 . That is, referring to FIGS. 1 and 2 , a nonionic surfactant and a heat-sensitive coagulant are added together in a mixture of a nonionic water-dispersible polyurethane (PUD) resin with a flame retardant (P, Br) and an aqueous pigment (black color). The cross-sectional photograph taken after impregnation of the nonwoven fabric shows that the resin and pigment are evenly distributed in the thickness direction of the nonwoven fabric. Meanwhile, in FIGS. 3 and 4 , it can be seen that the migration occurred very severely in the case where the nonionic surfactant and the thermal coagulant were not added, so that the resin and pigment were moved to the outer part of the nonwoven fabric.

As an example of manufacturing the fiber base layer (F), as a nonionic surfactant relative to 100 parts by weight of the nonionic polyurethane aqueous dispersion, for example, 3 parts by weight of Clariants' Emulsogen, 10 parts by weight of sodium chloride as a thermal coagulant, After preparing a blending solution with 20 parts by weight of a bromine-based flame retardant and 300 parts by weight of water for appropriate viscosity control, it is impregnated with fiber cloth after stirring, and after adjusting the amount of impregnation through a mangle, hot air drying in a tenter at 110° C. (F) is formed.

On the other hand, an anionic polyurethane aqueous dispersion suitable for skin is prepared by mixing one type of polyol selected from a mixture of polycarbonate diol and polycarbonate diol and polyether glycol and an ionic lower diol having a carboxyl group with an alicyclic diisocyanate or an aliphatic diisocyanate. The reaction is performed to prepare an isocyanate-terminated urethane prepolymer, and then the prepared urethane prepolymer is neutralized with an amine-based neutralizer, and then dispersed forcibly in water, followed by chain extension reaction with diamine.

At this time, the molar ratio of polycarbonate diol: polyether glycol is adjusted to 50 to 100: 0 to 50, and one type of diisocyanate selected from a mixture of alicyclic diisocyanate and aliphatic diisocyanate and 80 to 100° C. for 2 to 4 hours During the addition reaction, neutralization is carried out at a temperature of around 80 ° C. For forced dispersion in water, ion-exchanged water is added in an aqueous dispersion tank at around 60 ° C. It is preferable for the skin of artificial leather for automobile interior materials.

As an embodiment of the present invention for preparing an anionic polyurethane aqueous dispersion, as one synthesis example of the present invention, 0.7 moles of polycarbonate diol having a molecular weight of 2,000, 0.3 moles of polytetramethylene glycol (PTMG) having a molecular weight of 2,000, dimethylol butanoic 0.5 moles of acid (DMBA), 1.25 moles of isophorone diisocyanate (IPDI), and 1.0 moles of hexamethylene diisocyanate (HDI) were added to a reactor and reacted at 90° C. for 3 hours to prepare an isocyanate-terminated urethane prepolymer. A polyurethane aqueous dispersion having a solid content of 35% and a viscosity of 150 cps (25° C.) was prepared using 0.52 moles of triethylamine (TEA) as a neutralizer and 0.75 moles of ethylenediamine (ED) as a chain extender.

Next, a process for forming the surface film layer (S) by applying and drying the aqueous dispersion of anionic polyurethane prepared as described above on a release paper will be described.

At this time, more preferably, before applying the prepared anionic polyurethane aqueous dispersion on a release paper, the anionic polyurethane aqueous dispersion is mixed with one or more additives selected from a thickener, an aggregation inhibitor, a crosslinking agent, and an aqueous pigment. After preparing, the prepared compounding solution is applied on a release paper and dried to form a surface film layer (S).

Specifically, as the thickener added to the anionic polyurethane dispersion, cellulose-based thickeners such as carboxymethyl cellulose, hydroxyethyl cellulose, and methyl cellulose are possible, and polyacrylates and urethane-based thickeners are also possible. The amount used is preferably 0.5 to 2 parts by weight based on 100 parts by weight of the aqueous dispersion depending on the viscosity of the aqueous dispersion.

In order to prevent agglomeration of the aqueous dispersion particles and improve flowability (leveling property), silicone-based surfactants, particularly polyether-modified polydimethylsiloxane, are useful. The amount used is suitable for 0.5 to 4 parts by weight based on 100 parts by weight of the aqueous dispersion.

When a small amount of polyisocyanate, aziridine, carbodiimide, melamine, etc. is added as a crosslinking agent, the water resistance and chemical resistance of the urethane film can be improved. Among them, when 1 to 5 parts by weight of aliphatic polyisocyanate or aziridine is added based on 100 parts by weight of the aqueous dispersion, intermolecular cross-linking of molecular chains is formed, which is effective.

When coating the compounding solution on the release paper and drying it, it is advantageous to make the film state smooth by pre-drying for 2 minutes at a tenter temperature of about 70°C and secondary drying at about 110°C. If the thickness of the film is 20-50㎛, it shows sufficient physical properties for automobile interior materials. In general, when a film thickness of 30 µm or more is required, it is recommended to repeat coating and drying twice.

As an embodiment of manufacturing the surface film layer (S), 10 parts by weight of an aqueous pigment (Toner), 0.5 parts by weight of a cellulose-based thickener, 1.5 parts by weight of a silicone-based anti-aggregation agent, and an aziridine-based agent in 100 parts by weight of the anionic polyurethane aqueous dispersion A mixture was prepared by mixing 2 parts by weight of a crosslinking agent, applied on a release paper, and dried at 70° C. for 2 minutes and 110° C. for 2 minutes. Coating and drying were performed once more on the formed film layer in the same manner to prepare a film sheet having a film thickness of 40 μm. The film had a tensile strength of 300 kg/cm 2 , an elongation of 600%, and a 100% modulus of 30 kg/cm 2 , which was soft and had excellent physical properties.

On the other hand, the method of applying the two-component solvent-free adhesive is as follows. When manufacturing artificial leather by bonding the fiber base layer (F) and the surface film layer (S) using a two-component solvent-free adhesive, which is a mixture of hydroxy-terminated urethane propolymer, diisocyanate-based crosslinking agent, catalyst and additives, After supplying the hydroxyl-terminated urethane prepolymer and diisocyanate-based crosslinking agent, which are components of the two-component solvent-free adhesive, to the dispenser installed at the tip of the coater in a state of being separated from each other, coating on the surface film layer (S) at the same time as mixing to form a solvent-free adhesive layer (A). The hydroxyl-terminated urethane prepolymer suitable for the present invention has a molecular weight of 3,000 to 5,000 having a hydroxyl group (-OH) at both ends by adjusting the molar ratio of NCO:OH to 1:1.5 to 3.0 when the polyol and diisocyanate are additionally reacted. is a compound. That is, (i) polyether glycols such as polytetramethylene glycol (PTMG) and polypropylene glycol (PPG) having a molecular weight of 500 to 2,000, polybutylene adipate glycol (PBAG), and polyneopentyl adipate glycol (PNPAG) , at least one polyol component selected from polyols such as polyester glycol such as polycaprolactone glycol (PCL), polyester / ether copolymer glycol, polycarbonate diol, polycarbonate / caprolactone copolymer glycol, and (ii) diphenylmethanedi Isocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (H ₁₂ MDI) at least one diisocyanate component selected from 60 ~ A hydroxy-terminated prepolymer is synthesized by reaction at 100°C. It is a solid or semi-solid state at room temperature, and when it is melted at 50 to 60°C, a viscosity of 2,000 to 10,000 cps at the melting temperature is suitable.

Next, cross-linking agents and catalysts suitable for use in the present invention will be described. As a crosslinking agent for the hydroxyl-terminated prepolymer, diisocyanates that easily react with a hydroxyl group are suitable. Among them, modified diphenylmethane diisocyanate (MDI) having low viscosity because it is liquid at room temperature is suitable. Commercially supplied carbodiimide-modified diphenylmethane diisocyanate (MDI) (Kumho Mitsui Chemical cosmonate LL, etc.), diphenylmethane diisocyanate (MDI) prepolymer (BASF Korea Lupranate MP102, etc.), polymeric di with functional groups 2.5 to 2.7 Phenylmethane diisocyanate (MDI) is also possible.

This diisocyanate crosslinking agent is used in an equivalent ratio of OH:NCO to the urethane prepolymer in a ratio of 1:1.1 to 2.0. If it is 1.1 or less, crosslinking and curability are inferior, and if it is 2.0 or more, the degree of crosslinking is too large, so that the touch becomes hard and unreacted isocyanate remains, which may cause discoloration or deterioration of physical properties.

As a catalyst, "DABCO 33LV, Air Products" or "Toyocat-TF, Toso Corporation" etc. are suitable as a triethylenediamine (TEDA) type|system|group. As the dimethylcyclohexylamine (DMCHA) type, an amine compound such as "Polycat-8, Air Products" is also useful. 0.5 to 3.0 parts by weight is suitable for 100 parts by weight of the prepolymer.

The main agent, crosslinking agent, tertiary amine catalyst, silicone-based leveling agent, phosphorus-based or bromine-based flame retardant, etc. are mixed at the melting temperature of the main agent, coated with an adhesive layer, and pre-dried at 130-140° C. for 3-4 minutes, partial cross-linking As the reaction proceeds, a tackiness suitable for adhesion to the fiber base layer is expressed. It is appropriate to use 15 to 25 parts by weight of the crosslinking agent, 0.5 to 3 parts by weight of the catalyst and anti-agglomeration agent, and 5 to 15 parts by weight of the flame retardant based on 100 parts by weight of the main agent.

The present invention may further include a step of surface treatment through a gravure roll or a spray coater in order to control the surface color or gloss of the artificial leather having a three-layer structure from which the release paper is peeled off.

The following describes a specific manufacturing method of the present invention through examples.

Example 1

<Manufacture of polyurethane aqueous dispersion for impregnation>

Polytetramethylene glycol (PTMG) 0.75 moles of molecular weight (Mn) 2,000, polypropylene glycol (PPG) 0.25 moles of molecular weight 2,000, polyoxyethylene propylene glycol 0.43 moles, and isophorone diisocyanate (IPDI) 1.98 moles were put into the reactor and After reacting at 90° C. for 4 hours to confirm that the remaining isocyanate is at the level of 1.5% by weight, adding a small amount of acetone and antioxidant, stirring for 30 minutes, and stirring while dropping it into a dispersion tank filled with distilled water to obtain an aqueous dispersion with a solid content of 35% and a viscosity of 80 cps prepared.

<Manufacture of polyurethane aqueous dispersion for skin>

0.7 moles of polycarbonate diol having a molecular weight (Mn) of 2,000, 0.3 moles of polytetramethylene glycol (PTMG) having a molecular weight (Mn) of 2,000, and 0.5 moles of dimethylol butanoic acid (DMBA) were stirred at a temperature of 90 ° C. 1.25 moles of porone diisocyanate (IPDI) and 1.0 moles of hexamethylene diisocyanate (HDI) were put into a reactor and reacted for 3 hours to prepare an isocyanate-terminated urethane prepolymer. At this time, the content of the unreacted NCO group at the terminal was 2.5%. After cooling to 80°C, 0.52 moles of triethylamine (TEA) was added, neutralized for 30 minutes, moved to an aqueous dispersion tank at 60°C, dispersed forcibly with ion-exchanged water, and chained with 0.75 moles of ethylenediamine (ED) for 1 hour An extension reaction was carried out.

The polyurethane aqueous dispersion thus prepared was a white emulsion having a solid concentration of 35%, pH 7-8, and viscosity of 150 cps. Even after storage for more than 6 months, there was no change in viscosity in appearance.

<Production of two-component solvent-free adhesive>

The subject matter of the two-component solvent-free adhesive was synthesized as follows. 0.6 mol of polycarbonate/caprolactone copolymerized glycol (PCD/PCL) having a molecular weight of 2,000 and 0.4 mol of polytetramethylene glycol (PTMG) having a molecular weight of 2,000 were melt-mixed at 70-90° C., and melted diphenylmethane diisocyanate (MDI) After adding 0.45 mol, it was reacted at 70° C. for 3 hours to obtain a urethane prepolymer terminated with a hydroxyl group, and it was stored in a main tank kept at 60° C.

Carbodiimide-modified diphenylmethane diisocyanate (MDI) having an NCO content of 29.5% was used as a crosslinking agent. The viscosity of the crosslinking agent at room temperature was 50 cps. Dimethylcyclohexylamine (DMCA) was used as a catalyst.

In the main tank kept at 60° C., 2 parts by weight of the catalyst and 20 parts by weight of the bromine-based flame retardant were stored in 100 parts by weight of the main agent. The cross-linking agent and anti-aggregation agent were stored in a tank for cross-linking agent/additive in a ratio of 100 parts by weight: 5 parts by weight.

<Manufacture of three-layer structure artificial leather>

Compared to 100 parts by weight of the nonionic polyurethane aqueous dispersion, 3 parts by weight of fatty alcohol polyglycol ether as a nonionic surfactant, 10 parts by weight of sodium chloride as a thermal coagulant, 20 parts by weight of a bromine-based flame retardant, 200 parts by weight of distilled water After preparing a blending solution with 2 parts by weight of black aqueous pigment and stirring, it is impregnated with a needle punched nonwoven fabric with a unit weight of 300g/m² and a thickness of 1.3mm, and the mangle gap is padded with 50% of the thickness of the nonwoven fabric, followed by 110 Drying with hot air at ℃ to form a fiber base layer (F). An optical micrograph of a cross-section of the prepared fiber base layer (F) was shown in FIG. 1 , and an electron micrograph was shown in FIG. 2 . On the other hand, 0.5 parts by weight of a cellulose-based thickener, 1.5 parts by weight of a silicone-based anti-aggregation agent, 1.5 parts by weight of an aziridine-based crosslinking agent, and 10 parts by weight of a black aqueous pigment are added to 100 parts by weight of the aqueous dispersion of anionic polyurethane for the skin layer, and after sufficient stirring, the release paper phase and dried at 70° C. for 2 minutes and 110° C. for 2 minutes to form a skin layer (surface film layer) with a film thickness of 30 μm. On this skin layer, using a gear pump, the raw materials of the main tank and the crosslinking agent/additive tank are transferred to the mixer feeder at a ratio of 6:1 through a separate supply pipe, mixed and discharged at the same time, and the thickness is applied with a knife coater. After coating with 0.20mm, it was pre-dried at 135~140℃ for 3 minutes. Next, it was laminated with the fiber base layer prepared above and aged in an aging room at 60 to 70° C. for 48 hours, and then the release paper was peeled off.

Thereafter, using a conventional polyurethane resin for surface treatment, necessary post-processing such as gloss control and color control was performed with a surface treatment machine equipped with a gravure roll to complete artificial leather having a three-layer structure. The results of evaluating the properties of the manufactured artificial leather are shown in Table 1, and a cross-sectional photograph of the manufactured artificial leather is shown in FIG. 5 . The manufactured artificial leather has good bending characteristics and excellent adhesive strength and durability, making it suitable for interior materials such as car seats.

Example 2

<Manufacture of polyurethane aqueous dispersion for impregnation>

Polytetramethylene glycol (PTMG) 0.65 moles of molecular weight (Mn) 2,000, polypropylene glycol (PPG) 0.35 moles of molecular weight 2,000, polyoxyethylene propylene glycol 0.45 moles, isophorone diisocyanate (IPDI) 2.0 moles were put into the reactor, After reacting at 90° C. for 4 hours, it was confirmed that the remaining isocyanate is at the level of 1.4% by weight, and a small amount of acetone and antioxidants were added and stirred for 30 minutes. prepared.

<Production of polyurethane aqueous dispersion for skin>

When preparing an anionic polyurethane aqueous dispersion, 0.5 moles of polycarbonate diol (PCD) having a molecular weight of 2,000, 0.5 moles of polytetramethylene glycol (PTMG) having a molecular weight of 2,000 were used as polyols, and 0.75 moles of isophorone diisocyanate (IPDI) was used. A polyurethane aqueous dispersion was prepared under the same conditions and methods as in Example 1, except that 1.5 moles of hexamethylene diisocyanate (HDI) were used.

The prepared polyurethane aqueous dispersion was a white emulsion having a solid concentration of 35% and a viscosity of 50 cps, and there was no change in the viscosity even after storage for more than 6 months.

<Production of two-component solvent-free adhesive>

Melt and mix 0.75 mol of polytetramethylene glycol (PTMG) with a molecular weight of 2,000 and 0.3 mol of polycarbonate diol at 60 to 80 ° C. Add 0.4 mol of melted diphenylmethane diisocyanate (MDI) and 0.1 mol of toluene diisocyanate (TDI) and reacted at 60°C for 2 hours to synthesize a urethane prepolymer (main) terminated with a hydroxyl group and stored in a main tank kept at 60°C. A diphenylmethane diisocyanate (MDI)-based prepolymer having an isocyanate (NCO) content of 22.8% was used as a crosslinking agent. The viscosity at room temperature was 550 cps. The cross-linking agent and silicone-based anti-aggregation agent were stored together in a tank for cross-linking agent/additive in a ratio of 5 parts by weight of anti-aggregation agent to 100 parts by weight of cross-linking agent. In the main tank kept at 60° C., 2 parts by weight of the triethylenediamine catalyst and 20 parts by weight of the phosphorus-based flame retardant were stored in 100 parts by weight of the main agent.

<Manufacture of three-layer structure artificial leather>

Compared to 100 parts by weight of the nonionic polyurethane aqueous dispersion, 3 parts by weight of fatty alcohol polyglycol ether as a nonionic surfactant, 10 parts by weight of sodium chloride as a thermal coagulant, 20 parts by weight of a bromine-based flame retardant, 250 parts by weight of distilled water After preparing a blending solution with 2 parts by weight of black aqueous pigment and stirring, it is impregnated with 150 denier polyester interlock fabric (unit weight 250 g/m², thickness 0.85 mm), and the mangle gap is padded with 50% of the fabric thickness. and then dried with hot air at 110° C. in a tenter to form a fiber base layer (F).

0.5 parts by weight of a cellulose-based thickener, 1.5 parts by weight of a silicone-based anti-aggregation agent, 3 parts by weight of a polyisocyanate-based crosslinking agent, and 10 parts by weight of a black aqueous pigment were added to 100 parts by weight of the aqueous dispersion of anionic polyurethane for the skin layer, and after stirring sufficiently, on a release paper After coating, the skin layer (surface film layer) with a film thickness of 30 μm was formed by drying at 70° C. for 2 minutes and at 110° C. for 2 minutes.

On this skin layer, using a gear pump, the raw materials of the main tank and the crosslinking agent/additive tank are transferred to the mixing feeder at a ratio of 5:1 through a separate supply pipe, mixed and discharged at the same time, and the thickness is applied with a knife coater. It was coated with 0.15 mm. It was pre-dried at 130-135° C. for 3 minutes and 30 seconds, and then laminated with the fiber base layer prepared above. After that, it was aged for 48 hours in an aging room at 60-70° C. and the release paper was peeled off. Thereafter, an artificial leather having a three-layer structure was prepared by applying a general polyurethane resin for surface treatment with a gravure roll to control gloss and color.

As shown in Table 1, the result of evaluating the physical properties of the manufactured artificial leather was excellent and the touch was soft, so it was suitable as a material for a door trim of a car.

Comparative Example 1

It was synthesized in the same manner as in the synthesis of the aqueous dispersion of nonionic polyurethane for impregnation of Example 1, but a resin having a molar ratio of polytetramethylene glycol (PTMG) and polypropylene glycol (PPG) of 90:10 was used. The resin for the skin layer and the solvent-free adhesive resin used the same resin as in Example 1, and artificial leather was prepared in the same manner as in Example 1, and the manufactured artificial leather had a rather hard touch, so it was not suitable for vehicle interior materials.

As shown in Table 1, the result of evaluating the physical properties of the manufactured artificial leather was excellent and the touch was soft, so it was suitable as a material for a door trim of a car.

Comparative Example 2

It was synthesized in the same manner as in the synthesis of the aqueous dispersion of nonionic polyurethane for impregnation in Example 1, but a resin having a molar ratio of polytetramethylene glycol (PTMG) and polypropylene glycol (PPG) of 50:50 was used. For the skin layer resin and the solvent-free adhesive resin, the same resin as in Example 1 was used, and artificial leather was prepared in the same manner as in Example 1, and tacky remained in the fiber base layer of the artificial leather prepared under the influence of the impregnated resin. there was.

As shown in Table 1, the result of evaluating the physical properties of the manufactured artificial leather was excellent and the touch was soft, so it was suitable as a material for a door trim of a car.

Comparative Example 3

An artificial leather was prepared in the same manner as in Example 1 except that the aqueous dispersion of nonionic polyurethane for impregnation of Example 1 was used, except that the nonionic surfactant and thermal coagulant were excluded from the blending solution. As can be seen from FIGS. 3 and 4 , migration of the aqueous dispersion occurred in the nonwoven fabric, and thus the manufactured artificial leather also had poor bending characteristics.

At this time, the optical micrograph of the cross-section of the fabricated fiber base layer (F) was as shown in FIG. 3, and the electron micrograph was as shown in FIG.

As shown in Table 1, the result of evaluating the physical properties of the manufactured artificial leather was excellent and the touch was soft, so it was suitable as a material for a door trim of a car.

Performance evaluation result of artificial leather according to an embodiment of the present invention evaluation item unit Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 bend characteristics
(wrinkle characteristics) sensory evaluation fine wrinkles
(○) no wrinkles
(◎) small wrinkles
(△) fine wrinkles
(○) big wrinkles
(×) hydrolysis resistance class 4 4 3 3 4 wear resistance cycle 2,000↑ 1,500↑ 1,500↑ 1,500↑ 2,000↑ Adhesive strength kg/cm 2.5 1.5 2.0 2.2 1.7 light fastness class 4 4 4 3-4 4 heat resistance class 4-5 4-5 4-5 4 4-5 combustibility
(as presented/after high temperature) mm/min S.E./S.E. S.E./S.E. S.E./S.E. S.E./S.E. S.E./S.E. DMF Residue ppm N.D. N.D. N.D. N.D. N.D. Heavy metals and hazardous substances ppm not detected not detected not detected not detected not detected

Various physical properties in Table 1 were evaluated in the following manner.

● Bending characteristics (wrinkle characteristics): The size of wrinkles that occur when artificial leather is folded in the longitudinal and width directions was evaluated in 4 grades.

● Hydrolysis resistance test: Measured according to MS 256-26, Autoclave test (120℃*100%RH*48HR) standard

: Grade 1 (poor) to Grade 5 (good), evaluation of the degree of crumbling, stickiness, rusting, residuals and cracks impairing practicality.

● Abrasion resistance test: Measured according to MS 300-31, CS-10, and 1000g standards.

● Adhesive strength: Measured according to ASTM D2724 standard.

● Light resistance: Measured according to MS 210-05, Section 4.5.

: Grade 1 (poor) to Grade 5 (good), visually visible torsion, deformation, discoloration, cracks, residuals, peeling, change in hardness or stickiness

● Heat resistance: Measured according to MS 210-05, Section 4.4.

: Same as light fastness evaluation

● Flammability : Measured according to MS 300-08 standard. S.E stands for self-extinguishing

● DMF residual amount: measured according to USA EPA 8270D (ISO TS 16189) standard.

● Heavy metals and hazardous substances: Measured according to MS 201-02 standard.

In the above, the MS evaluation standard is the automobile interior material evaluation standard for polyurethane artificial leather of Hyundai/Kia Motors.

According to the evaluation results in Table 1, the artificial leather of the present invention has a uniform state in which the water-based polyurethane resin is impregnated into the fiber fabric, particularly the non-woven fabric, and thus secures the fine wrinkle characteristics particularly required for molding processing for automobile interior materials, and at the same time The amount of DMF remaining in the product has been dramatically reduced compared to the existing solvent-type products, and important properties also satisfy the required property standards.

S: surface film layer
A: Solvent-free adhesive layer
F: fiber base layer

Claims (4)

(i) a process of impregnating the textile fabric with an aqueous dispersion of a nonionic water-dispersible polyurethane resin and drying it to form a textile base layer (F); (ii) forming a surface film layer (S) by applying and drying an anionic polyurethane aqueous dispersion on a release paper; (iii) forming a solvent-free adhesive layer (A) by applying and drying a two-component solvent-free polyurethane adhesive solution on the surface film layer (S); and (iv) laminating, drying and aging the fiber base layer (F) on the solvent-free adhesive layer (A) by a laminating method, and then peeling the release paper from the surface film layer (S) and then surface-treating; A method of manufacturing an eco-friendly artificial leather for automobile interior material to which a water-dispersible polyurethane resin is applied, characterized in that The method of claim 1, wherein the nonionic water-dispersible polyurethane resin impregnated into the textile fabric is a diol component consisting of polytetramethylene glycol (PTMG), polypropylene glycol (PPG) and polyoxyethylene propylene glycol, an alicyclic diisocyanate, and A method of manufacturing an eco-friendly artificial leather for automobile interior material using a water-dispersible polyurethane resin, characterized in that it is prepared by reacting one type of diisocyanate component selected from among aliphatic diisocyanates. The water dispersion according to claim 2, wherein the molar ratio of polytetramethylene glycol (PTMG) and polypropylene glycol (PPG) is adjusted to 60-80:40-20 when synthesizing the nonionic water-dispersed polyurethane resin. A method of manufacturing eco-friendly artificial leather for automobile interior materials using polyurethane resin. According to claim 1, before impregnating the textile fabric with the aqueous dispersion of the nonionic water-dispersed polyurethane resin, fatty alcohol polyglycol ether ( 1 to 5 parts by weight of fatty alcohol polyglycol ether), 5 to 15 parts by weight of inorganic salts as a heat-sensitive coagulant, 10 to 30 parts by weight of a bromine-based or phosphorus-based flame retardant, and 100 to 300 parts by weight of water as a viscosity modifier are mixed and stirred to prepare a mixture. Then, after impregnating the blending solution into the fiber fabric, the amount of impregnation is adjusted through a mangle and hot air dried at 100 to 120° C. in a tenter to form a fiber base layer (F). A manufacturing method of eco-friendly artificial leather for automobile interior materials applied.

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