KR101054372B1 - Water Soluble Polyurethane Paint Composition - Google Patents

Abstract

The present invention relates to a water-soluble polyurethane coating composition, more specifically, 25 to 40% by weight of water-soluble hydroxyl polyester-polyurethane dispersion, 20 to 35% by weight of polyurethane dispersion, 4 to 8 water-dispersible polyisocyanate 1% to 5% by weight of fumed silica treated with a polydimethylsiloxane surface treatment agent having a particle size of 3 to 6 microns, 1 to 5% by weight of wax-modified silica having a particle size of 5 to 12 microns, and 0.1 to 1 epoxysilane Soft and elastic texture of the hard and cold properties of plastics and steel materials, including weight percent, 0.1-1 weight percent surface lubricant, 0.1-1 weight percent nonionic hydrophobic surfactant, and 20-30 weight percent ion-exchanged water The present invention relates to a water-soluble polyurethane coating composition that can be modified with excellent coating properties such as scratch resistance, chemical resistance, abrasion resistance, and durability.

Polyester-Polyurethane Dispersion, Water Soluble Polyurethane Paint Composition, Plastic, Soft Peel

Description

Water-soluble polyurethane coating composition {Composition for aqueous polyurethane coating}

The present invention relates to a water-soluble polyurethane coating composition, more specifically, 25 to 40% by weight of water-soluble hydroxyl polyester-polyurethane dispersion, 20 to 35% by weight of polyurethane dispersion, 4 to 8 water-dispersible polyisocyanate 1% to 5% by weight of fumed silica treated with a polydimethylsiloxane surface treatment agent having a particle size of 3 to 6 microns, 1 to 5% by weight of wax-modified silica having a particle size of 5 to 12 microns, and 0.1 to 1 epoxysilane Soft and elastic texture of the hard and cold properties of plastics and steel materials, including weight percent, 0.1-1 weight percent surface lubricant, 0.1-1 weight percent nonionic hydrophobic surfactant, and 20-30 weight percent ion-exchanged water The present invention relates to a water-soluble polyurethane coating composition that can be modified with excellent coating properties such as scratch resistance, chemical resistance, abrasion resistance, and durability.

In general, steel has excellent rigidity depending on its inherent characteristics, but there is a problem that rust occurs when exposed to moisture, and plastics are vulnerable to chemicals, erosion, ultraviolet rays, and discoloration. Has surface defects. In order to solve these problems, conventionally, a solvent type or a water-soluble paint is applied to compensate for the shortcomings of steel or plastic materials, and at the same time, color has been improved to improve appearance. However, as society develops, the demand level of consumers' products is also increasing. Recently, the materials that are frequently encountered in real life are given not only physical properties and appearance, but also soft and luxurious textures to the surface characteristics of the materials to satisfy consumer needs. To meet more.

For example, among the components that make up automobile interior materials, handles, buttons, airbag covers, etc., have already been applied to soft peel paints long ago, and they have been commercialized in electronic products such as vacuum cleaners, laptops, and mobile phones. The trend is expanding. The characteristics of texture paints are various textures such as leather, velvet, rubber, etc. according to the requirements of users and applied parts. Recently, there is a tendency to convert from solvent type to water-soluble paints according to the environmental regulation of organic compounds.

In order to differentiate and diversify automobile designs, the growth rate of the automotive parts paint market is expected to slow down by introducing film laminates, wood grains, and graphics. However, the market for special effect paints such as soft fill is expected to expand.

Polyurethane dispersions are widely used for automotive plastic paints because they exhibit excellent physical properties in wear, impact, scratch resistance, etc., which are easy to adjoin packing effect due to small particle size and narrow molecular weight distribution. Fusion and so on.                         

Polyurethane dispersions can be manufactured from hard and hard to soft and flexible polymers. Various plastic materials used in the automotive industry expand the area of polyurethane dispersion resins in terms of improving physical properties and appearance quality. have.

As European car manufacturers use more thermoplastics with relatively lower heat resistance, coating systems that need to be applied above 120 ° C cannot be used. Thus, two-component polyurethane systems are preferred which can be cured even at room temperature.

Soft peel coating should not only have a soft and warm effect but also have coating properties such as light resistance, chemical resistance and scratch resistance. This property can be obtained by crosslinking a high molecular weight flexible polyurethane dispersion with a water dispersible polyisocyanate. In addition to the polyurethane forming reaction from isocyanates and polyols, polyureas are also formed through addition reactions of NCO groups with water. The high molecular weight polyurethane dispersion is networked in the form of polyurethane and polyurea sandwiched.

The film texture of the existing water-soluble two-component polyurethane soft peel paints is similar to that of conventional solvent-based coatings, but because the water is inferior in solvent solubility, the main solvent is used. Accordingly, there is a demand for the development of a paint which can prevent cracks and erosion of the plastic surface due to the solvent attack in the solvent-type coating while having a similar level of physical properties as the solvent-type coating.                         

Recently, there is a demand for the development of a water-soluble soft peel paint having excellent paint film properties such as chemical resistance, abrasion resistance, alcohol resistance, scratch resistance, etc., due to enhanced quality of automotive plastic interior coating materials.

In the present invention, in order to solve the problems described above, the resin and the matting effect of the polyurethane dispersion, the water-soluble hydroxyl polyester-polyurethane dispersion, and the water-dispersible polyisocyanate to form a coating film of the soft-fill characteristics, the texture Water-soluble polyurethane that improves the weak physical properties of conventional water-soluble paints by using silica that complements properties, epoxy silanes for modifying coating properties, and additives for coating film formation and appearance enhancement, and at the same time gives a coating with excellent texture and appearance properties. The composition was derived and the present invention was completed based on this.

An object of the present invention is to provide a water-soluble polyurethane composition having excellent coating properties such as scratch resistance, chemical resistance, abrasion resistance and durability, less smell after drying the coating film, and excellent texture properties.

The water-soluble polyurethane composition for achieving the above object is 25 to 40% by weight of water-soluble hydroxyl polyester-polyurethane dispersion, 20 to 35% by weight of polyurethane dispersion, 4 to 8% by weight of water dispersible polyisocyanate, 3 to 6 1-5% by weight of modified fumed silica treated with polydimethylsiloxane surface treatment agent having a particle size of micron, 1-5% by weight of wax-modified silica having a particle size of 5-12 microns, 0.1-1% by weight of epoxy silane, surface lubricant 0.1-1 weight%, 0.1-1 weight% of nonionic hydrophobic surfactant, and 20-30 weight% of ion-exchange water.

The present invention is a polydimethylsiloxane having a particle diameter of 25 to 40% by weight of water-soluble hydroxyl polyester-polyurethane dispersion, 20 to 35% by weight of polyurethane dispersion, 4 to 8% by weight of water dispersible polyisocyanate, and 3 to 6 microns. 1-5% by weight of modified fumed silica treated with an acid-based surface treatment agent, 1-5% by weight of wax-modified silica having a particle size of 5-12 microns, 0.1-1% by weight of epoxysilane, 0.1-1% by weight of surface lubricant, nonionic It is related with the water-soluble polyurethane coating composition containing 0.1-1 weight% of system type hydrophobic surfactant, and 20-30 weight% of ion-exchange water.

Hereinafter, the present invention will be described in detail.

The polyester-polyurethane dispersion having a water-soluble hydroxy group used in the present invention preferably has a number average molecular weight of 5,000 to 30,000 and an elongation of 400 to 800%. When the elongation of the resin is lower than the above range, the characteristics of the texture paint are lost, and when the elongation of the resin is high, viscous properties remain on the coating film, whereby physical properties such as stain resistance, scratch resistance, and wear resistance may decrease.

The hydroxyl polyester-polyurethane dispersion resin is used 25 to 40% by weight based on the total coating composition, when the amount is less than 25% by weight, physical properties such as adhesion, hardness of the coating film is reduced, 40% by weight If is exceeded, the soft texture is reduced.

Polyurethane dispersion used in the present invention is a polyether, polyester or polycarbonate-based number average molecular weight of 10,000 to 100,000, elongation of 500 to 1,000%, hydroxyl content of 1 to 3%, tensile strength of 3,000 ~ It is more preferable that the particle size is 6,000 psi and 50-300 nm. If the elongation of the resin is less than 500%, the soft touch, which is a characteristic of the texture paint, is lost. If the elongation exceeds 1,000%, the viscosity remains on the coating film, and thus physical properties such as stain resistance, scratch resistance, and wear resistance may be reduced. The amount of the polyurethane dispersion is 20 to 35% by weight, and less than 20% by weight of the coating film is less effective in texture, and when it exceeds 35% by weight, the physical properties of the coating film are lowered.

The composition of the present invention requires mechanical properties and chemical resistance such as wear resistance, scratch resistance, light resistance, chemical resistance, etc. while maintaining a soft coating film for use, and thus maintains a flexible and elastic coating film to maintain a crosslinked density of a certain level or more. The skill to give is necessary. Therefore, while a coating composition using a polyurethane resin is weak in physical properties such as hardness of the coating film, the coating composition using a mixed resin of the hydroxyl polyester-polyurethane dispersion and the polyurethane dispersion of the present invention is crosslinked with a curing agent. The hardness of the coating film is excellent due to the flexibility of the after coating film and the film density.

At this time, the ratio of resin use ratio of the water-soluble hydroxyl polyester-polyurethane dispersion and the polyurethane dispersant is in the ratio of 1: 1 to 2: 1 based on solids, and the amount of hydroxyl polyester-polyurethane dispersant is used. If there are many, the coating properties are excellent, but the texture is lowered, if less, there is a problem that the chemical resistance is lowered.

On the other hand, in order to form a coating film of the water-soluble hydroxyl resin, a curing agent capable of bonding with a hydroxyl group is required. As the curing agent of the modified polyether type which is easy to disperse water as described above, in the present invention, 4 to 8% by weight of a urethane type water dispersible polyisocyanate having an equivalent weight of 200 to 300, for example, hexamethylene diisocyanate, is used.

The combination of isocyanate and hydroxyl polyester-polyurethane dispersion forms a rigid polyurethane coating, and in addition, the isocyanate group and water react to form a polyurea. As a result, the structure of the polyurethane film through the reaction has a form in which the polyurethane and polyurea are entangled in a mesh with each other.

In addition to the polyisocyanate-based curing agent, crosslinking can be formed by using a curing agent such as aziridine or carbodiimide, but its structure is inferior to the isocyanate-hydroxyl crosslinking density, so that the physical properties such as sensitivity, light resistance, and chemical resistance are insufficient. Indicates.

Since the crosslinking of the water-soluble polyurethane resin is accompanied by an addition reaction, the reaction ratio (NCO / OH) of isocyanate and hydroxyl groups should be used in the range of 1.3 to 1.8, and if it is small, the coating film properties such as wear resistance and chemical resistance will be reduced. At high temperatures, the coating becomes hard and loses its texture.

On the other hand, since the water-soluble polyurethane coating composition of the present invention is a textured coating for indoor use, a low gloss of 2 ^o or less is required on the basis of a glossometer 60 ^o gloss in appearance.

The degree of gloss is influenced by factors such as the roughness of the coating surface, the form of solvent evaporation and film shrinkage, the coating process, the temperature and humidity conditions, the composition of the solvent and the additive, and are primarily determined by the roughness of the coating film surface.

In order to show the effect of surface roughness, materials generally used in paints include silica, talc, calcium carbonate, etc. After the paint is coated on the substrate, the matting agent is uniformly distributed in the wet coating film. As the solvent or water evaporates, the thickness of the coating film decreases, and as the film shrinks, a rough surface of the matting agent appears. At this time, irradiated light diffuses and scatters on the rough surface, so that the high and low gloss can be recognized. do.

In general, the gloss decreases as the amount of the matting agent is increased, and as the particles of silica become rough, a low gloss coating film is formed.

Silica, a component for reducing the glossiness of a coating film, can be generally classified into heat treatment, sinking type, organic coating, fumed, wax coated silica, etc. according to the manufacturing method, and physical properties such as transparency, matting efficiency and scratch resistance of the dry coating film. In order to secure it is advantageous to use a silica prepared by a heat treatment method excellent in hardness characteristics. Surface texture can be improved when using waxed silica.

The porous properties of silica show a high quenching effect, but when used in a large amount, it can absorb the resin powder and cause a decrease in the softness of the coating or the coating film. Since the amorphous film is formed irregularly on the surface, it is weak to scratches.

In the present invention, 1 to 5% by weight of modified fumed silica treated with a polydimethylsiloxane-based surface treating agent having a particle size of 3 to 6 microns having excellent scratch resistance and not affecting stiffness is used. If the amount is less than 1% by weight, the scratch resistance is lowered. If the amount is more than 5% by weight, the selectivity is lowered. In addition, in order to improve the surface texture, 1 to 5% by weight of wax-modified silica having a particle diameter of 5 to 12 microns is used, and when the amount thereof is less than 1% by weight, it is difficult to expect the effect. This results in deterioration of the physical properties.

When the amount of the modified fumed silica treated with the polydimethylsiloxane-based surface treatment agent is high, the surface texture characteristics are insufficient, and when the amount of the wax-modified silica is relatively high, scratch resistance and screening resistance may be reduced.

In general, epoxy silane has a function of inducing bonding with silica to improve chemical resistance and solution stability. Epoxy silane used in the paint may be largely used vinyl ethoxysilane, vinyl methoxy silane, methyl diethoxy silane, gamma methacryloxypropyl triethoxy silane and gamma methacryloxy propyl trimethoxy silane, and preferably It is preferable to use methyl diethoxy silane that exhibits physical properties such as adhesion and storage stability effectively.

 In the present invention, 0.1 to 1% by weight of epoxy silane is used to improve the wear resistance of the coating due to the texture characteristics.

If the amount of the epoxy silane is less than 0.1% by weight, the effect of improving physical properties is less. If the amount of the epoxy silane exceeds 1% by weight, poor paint storage property may be caused.

In addition, in the present invention, nonionic hydrophobic surfactants such as siloxane-based, sulfone-based, and ethoxy-modified polyether-based surfactants may be used for surface wetting of plastic materials, and preferably, antifoaming and dynamic surface tension 0.1-1 weight% of the acetylenic diol type surfactant which is excellent in the fall effect is used.

As the surface lubricant used in the present invention, acrylic, polyester, or polyether modified polysiloxane may be used to ensure coating smoothness, and the amount of the polyether modified siloxane based lubricant may be 0.1 to 1% by weight based on the total coating composition. It is preferable to use as.

In the coating composition of the present invention, ion exchange water is used in an amount of 20 to 30% by weight, and when the amount thereof is less than 20% by weight, the viscosity of the paint is high and workability is lowered. .

In addition, in the coating composition of the present invention, water and the like may be used as necessary for adjusting the pigments, additives and paint viscosity known in the art. Pigments include inorganic or organic coloring pigments, and additives include dispersants, neutralizers, antifoaming agents, and the like.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. However, the scope of the present invention is not limited to the following examples.

Example

To the coating composition was prepared with the composition components and contents as shown in Table 1 below.                     

A) A hydroxyl polyester-polyurethane dispersion having a number average molecular weight of 5,000 to 30,000 and an elongation of 400 to 800% as an aliphatic polyester system.

B) Polyether-based water-soluble polyurethane resin with a number average molecular weight of 10,000 to 100,000, particles of 50 to 300 nm, elongation of 500 to 1000%, and tensile strength of 3000 to 6000 PSI.

C) Water Dispersible Polyisocyanate (HDI TRIMER)

D) Modified Fumed Silica Treated with Polydimethylsiloxane Surface Treatment

E) Wax Modified Silica

F) methyldiethoxysilane

G) acetylenic diol nonionic surfactant

H) Polysiloxane Surface Lubricant

I) antifoam                     

J) Ion Exchange Water

K) colorant (black)

The hydroxyl polyester-polyurethane dispersion A) and the water-soluble polyurethane resin B) are placed in a container and mixed at low speed using a stirrer. During stirring, fumed silica D) treated with a polydimethylsiloxane-based surface treatment agent is added thereto, and dispersed at 1000 rpm for 10 minutes. Methyl ethoxysilane F), an acetylenic diol nonionic surfactant G), a polysiloxane surface lubricant H) and a colorant K) were added and stirred at 1000 rpm for 10 minutes. After 10 minutes of stirring at 800 rpm with wax-modified silica E), the viscosity of the main part and the water-dispersible polyisocyanate (C) of HDI TRIMER (C) were adjusted by using ion-exchanged water to the pod cup NO # 4 35-40 seconds. Mix the curing agent part.

After spray coating the dry coating thickness of 30 microns to ABS specimens using the respective compositions, the physical properties of the specimens were dried for 30 minutes at a temperature of 80 ℃ and left for 24 hours to evaluate the physical properties.

The physical properties of the coating film prepared as described above were measured as follows, and the results are shown in Table 2) below.

1) texture

-After coating paint on plastic material, dry it at 80 ℃ for 30 minutes and compare the degree of bubble, foreign matter, spot, groove, and smoothness of surface with 1.5 ~ 2 standard on 60 'gloss standard. It was.                     

2) texture

-The elasticity and the touch of the dried coating film were compared.

3) adhesion

-According to ASTM D3359 tape adhesion test method, the degree of peeled part after tape adhesion test in 100 1 mm x 1 mm scales was observed.

4) Chemical resistance

-75% aqueous solution was prepared using isobutyl alcohol, ethanol and methanol, and the result of 20 round trip rub test was observed after soaking in a soft cloth.

5) Weather resistance

After 500 hours of testing at a panel panel temperature of 83 ± 3 ° C with an accelerated weather resistance tester using a xenon light source, the presence of defects that became a practical problem was observed.

6) wear resistance

-The degree of wear was compared when the test was performed 1000 times perpendicular to the coating surface with a load of 1000 g using a 100 mm stroke, 100 mm per second moving tester.

7) smell                     

The completely dried coating film was left at room temperature for 7 days, cut into squares of 10 cm × 10 cm, placed in a fully sealed steel container, and then heated in a heating furnace adjusted to 110 ° C. for 5 hours. When the test was completed, the container was left at room temperature for 2 hours, and then the lid was opened to compare the degree of smell.

Evaluation: Excellent 5 ←---→ 1 Poor

As shown in Table 2), the coating film prepared using the coating composition according to the present invention has excellent soft texture, less smell after drying, and excellent durability such as adhesion, chemical resistance, and weather resistance.

As described above, the present invention makes it possible to modify the hard and cold characteristics of the material into a soft and elastic texture by applying a water-soluble polyurethane paint to steel or plastic materials, and at the same time, coating properties such as scratch resistance, chemical resistance, abrasion resistance, and durability. It provides a water-soluble polyurethane coating composition that can improve.

Claims (5)

Water-soluble hydroxyl polyester-polyurethane dispersion 25-40% by weight, polyurethane dispersion 20-35% by weight, water dispersible polyisocyanate 4-8% by weight, polydimethylsiloxane surface treatment having a particle size of 3-6 microns 1 to 5% by weight of zero treated fumed silica, 1 to 5% by weight of wax-modified silica having a particle size of 5 to 12 microns, 0.1 to 1% by weight of epoxysilane, 0.1 to 1% by weight of surface lubricant, nonionic hydrophobic surfactant A water-soluble polyurethane coating composition comprising 0.1 to 1% by weight and ion exchanged water 20 to 30% by weight. The water-soluble hydroxyl polyester-polyurethane dispersion has a number average molecular weight of 5,000 to 30,000 and an elongation of 400 to 800%. According to claim 1, Polyurethane dispersion is a water-soluble poly, characterized in that the number average molecular weight of 10,000 to 100,000, elongation of 500 to 1,000%, tensile strength, 3,000 to 6,000 psi, particle size of 50 to 300nm polyether-based Urethane coating composition. The water-soluble polyurethane coating composition according to claim 1, wherein the water dispersible polyisocyanate is a polyether-modified type and is equivalent to 200 to 300 hexamethylene diisocyanate. The water-soluble polyurethane coating composition according to claim 1, wherein the weight ratio of the water-soluble hydroxyl polyester-polyurethane dispersion and the polyurethane dispersion is 1: 1 to 2: 1 based on solids.