KR101044115B1 - Method for preparing water dispersion polyurethane resin composition for coating of automotive plastic interior materials, and paint composition prepared using the same - Google Patents

Abstract

The present invention relates to a method for producing a water-dispersible polyurethane resin composition for coating automotive plastic interior materials and a coating composition comprising a polyurethane resin composition prepared by the above method, for coating plastic interior materials such as handles, instrument panels, etc. The present invention relates to a method for producing a water dispersible polyurethane resin composition which can be used as a main resin for a coating and to a coating composition comprising the polyurethane resin composition produced by the above method. The resin composition prepared according to the present invention has a soft texture such as leather texture while minimizing the use of solvents that cause environmental problems, and is less damaging to chemicals or external physical stimuli and thus has properties such as water resistance and scratch resistance. great.

Automotive interior materials, polyurethane resins, acetone, polyester polyols, isocyanates, polyurethane paints

Description

Method for preparing water dispersion polyurethane resin composition for coating automotive automotive interior materials, and paint composition prepared using the same}

The present invention relates to a method for producing a water-dispersible polyurethane resin composition for coating automotive plastic interior materials and a coating composition comprising a polyurethane resin composition prepared by the above method, for coating plastic interior materials such as handles, instrument panels, etc. The present invention relates to a method for producing a water-dispersible polyurethane resin composition used as a main resin for a coating and a coating composition comprising the polyurethane resin composition produced by the above method.

In general, the polyurethane resin is two-component, excellent in low-temperature curability, flexibility and durability of the coating film, and good balance. For this reason, polyurethane resin is used as a main raw material for plastic paints.

The characteristics of the polyurethane coating and coating film are summarized into the following four items.

1) Low temperature curability (can be cured at room temperature to 80 ℃)

2) Degree of freedom in design of coating film                         

3) Excellent appearance (high gloss, sharpness)

4) Excellent chemical and weather resistance

Among these, the low temperature hardenability and the high degree of freedom in design of a coating film are the suitable reasons for the coating of plastics. In this case, the low temperature curing property is required because the heat resistance of the plastic substrate is relatively low, and the reason for the flexibility is that even if the plastic substrate is in a flexible state, even if the coating film is cured, even the plastic substrate may be easily damaged by the impact.

Polyurethane paints can be divided into two types, solvent type and water soluble. In relation to environmental problems, development of raw materials for water-soluble polyurethane paints is being carried out as environmental protection paints.

In general, water-based polyurethanes are the mainstream of water-dispersible polyurethane (hereinafter referred to as PUD) obtained by aqueous polyurethane dispersion.

However, even if such a PUD is for an automobile exterior or interior paint, it is difficult to apply to a site requiring chemical resistance or high durability. In order to satisfy these demands, an aqueous two-component polyurethane coating has been developed aiming at low temperature curability and coating properties equivalent to those of a solvent-type two-component polyurethane coating. Such water-based paints are suitable for plastic paints in two ways.

1) Solvent cracks in plastic substrates are unlikely to occur due to the small amount of solvent used.                         

2) The method of the aqueous primer can make the flexibility higher than the solvent type.

Conventional US Pat. No. 6,414,079 includes aqueous solutions of hydroxyl-containing polyester-urethanes and triazine resins of aqueous dispersions, wherein the polyester-urethanes are linear, branched or cyclic aliphatic or aromatic multifunctional carboxylic acids and aliphatic linear or A waterborne binder for coatings of soft texture prepared by reacting a branched multifunctional alcohol with a multifunctional isocyanate is described.

U.S. Pat.No. 6,211,286 also includes aliphatic water-soluble or water-dispersible polymers having cyclic carbonates at the side chains or ends and amines having at least two primary amino groups, wherein the ratio of amine groups to cyclic carbonates is 7: 3 to 3: A binder for a coating material having a soft texture of 7 is described.

In these prior arts, polyester polyol, dimethylolpropionic acid (hereinafter referred to as DMPA) and isocyanate are reacted under N-methylpyrrolidone (NMP) solvent and neutralized with neutralizing agent. It is synthesized through the process of water dispersion. As such, there is a problem causing environmental problems because a large amount of a solvent such as NMP is used. In addition, improvement of physical properties such as smooth texture, water resistance, scratch resistance, and the like is continuously required.

The present inventors have completed the present invention as a result of research and review to supplement the problems of the prior art.

Accordingly, an object of the present invention is to contain a solvent such as NMP hardly caused by environmental problems, water-dispersible polyurethane resin composition for coating the automotive plastic interior material that can improve the physical properties such as smooth texture, water resistance, scratch resistance, etc. It is to provide a coating composition comprising a manufacturing method and a resin composition prepared according to the above method.

Method for producing a water-dispersible polyurethane resin composition for automotive plastic interior coatings according to the present invention for achieving the above object,

20 to 50 parts by weight of polyester polyol and 5 to 10 parts by weight of DMPA were dissolved in 10 to 25 parts by weight of NMP, and then reacted with 5 to 20 parts by weight of isocyanate to terminate the reaction when NCO became 0% and neutralized with amine. After water dispersion to provide a hydroxyl group-containing polyurethane resin;

10 to 30 parts by weight of polyester polyol and 2 to 10 parts by weight of DMPA are dissolved in 10 to 45 parts by weight of acetone, and reacted with 5 to 15 parts by weight of isocyanate to terminate the reaction at the point where NCO is 2 to 3%. Neutralizing and then dispersing and reacting by adding 3 to 10 parts by weight of a chain extender, and distilling acetone off completely to provide a flexible polyurethane resin; And

Mixing and stirring the hydroxyl group-containing polyurethane resin and the flexible polyurethane resin in a ratio of 1 to 1.5: 1.

In addition, the paint composition according to the present invention for achieving the above object includes a resin composition prepared according to the above method.

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

As mentioned above, the aqueous resin which can express the soft texture for automobile interior materials which comprise the resin composition which concerns on this invention can be divided roughly into hydroxyl-containing polyurethane resin and flexible polyurethane resin. In other words, the remaining OH group of the hydroxyl group-containing polyurethane resin and the remaining NCO group of the flexible polyurethane resin is composed of a system for curing reaction in the production of paint.

In other words, a large feature of the present invention is that the production of a flexible polyurethane resin using acetone instead of NMP, which is conventionally used in the synthesis, since the acetone can be completely removed after the reaction is completed, the content of the solvent is minimized. In addition, when using acetone as a solvent, the reaction may take a long time by using a isocyanate having a fast reaction to compensate for the long reaction time.

The water-dispersible polyurethane resin composition for automotive plastic interior coating according to the present invention is prepared as follows.

1) Manufacture of hydroxyl-containing polyurethane resin

First, a polyester polyol is prepared by polymerizing glycol and acid in the presence of a catalyst. The glycols used in the preparation of the polyester polyols are selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol and polyethylene glycol. The acid used may be selected from adipic acid or isophthalic acid. The reaction conditions for producing the polyester polyol can be carried out according to the conventional synthesis conditions, it can be carried out at 100 ~ 200 ℃. Moreover, when reaction temperature is 180 degreeC or more, inert gas, such as nitrogen gas, is supplied and yellowing of polyester polyol resin is suppressed. In addition, the polyester polyol used in the present invention has a hydroxyl group at both terminals, and preferably has a molecular weight of 1200 to 2000.

Further, 20 to 50 parts by weight of the polyester polyol and 5 to 10 parts by weight of DMPA were dissolved in 10 to 25 parts by weight of NMP, and then reacted with 5 to 20 parts by weight of isocyanate to terminate the reaction at the point where NCO became 0%. It is neutralized with an amine and then dispersed in water to prepare a hydroxyl group-containing polyurethane resin.

The isocyanate is at least one selected from the group consisting of isophorone diisocyanate, 1,6-hexamethylene diisocyanate and tetramethyl xyylene diisocyanate. When the content of isocyanate exceeds 20 parts by weight, the hard segment is increased. The soft texture is dropped during paint production, and less than 5 parts by weight, the curability is poor during paint production.

If the content of the polyester polyol exceeds 50 parts by weight, the content of the soft segment (soft segment) is increased so that the soft texture is excellent but the scratch resistance is lowered, if less than 20 parts by weight of the soft segment lacks the soft texture . In addition, when the content of the DMPA exceeds 10 parts by weight, the acid value of the resin is increased and the particle size is reduced, the water resistance is lowered, if less than 5 parts by weight adhesion is poor. In addition, when the content of the NMP exceeds 25 parts by weight, the content of the total solvent is increased during the manufacture of the paint to increase the content of VOC, if less than 10 parts by weight, the viscosity is increased in the synthesis of the resin is lowered in the stability during synthesis.

In addition, when the NCO of the reaction mixture reaches 0%, the reaction is terminated, neutralized with amine, and water is added thereto to disperse water. The amine used is not particularly limited, but ethylenediamine, triethylamine and dimethylethyl are used. One or more selected from the group consisting of amines may be used. In the case of water dispersion, in consideration of reactivity with isocyanate, water dispersion is preferably carried out at 30 to 40 ° C.

2) Manufacture flexible polyurethane resin

Apart from the step of preparing the hydroxyl group-containing polyurethane resin described above, a flexible polyurethane resin is prepared. Polyester polyol, DMPA, isocyanate, amine and the like may be the same as those used in the hydroxyl group-containing polyurethane resin among the components necessary in the manufacturing step of the flexible polyurethane resin.

The flexible polyurethane resin is dissolved in 10 to 30 parts by weight of polyester polyol and 2 to 10 parts by weight of DMPA in 10 to 45 parts by weight of acetone and reacted with 5 to 15 parts by weight of isocyanate to react when the NCO reaches 2 to 3%. After completion | finish, it neutralizes with an amine, it is made to disperse | distribute, and it is made to react by adding 3-10 weight part of chain extenders, and acetone is distilled off and it removes completely.

In the manufacturing step of the flexible polyurethane resin, when the content of the polyester polyol exceeds 30 parts by weight, the amount of soft segment is increased and the scratch resistance is lowered, if less than 10 parts by weight, soft texture is not enough due to the lack of soft segment Will fall. In addition, when the content of the DMPA exceeds 10 parts by weight, the acid value of the resin is increased, the particle size is reduced and the water resistance is lowered, if less than 2 parts by weight, the adhesion is poor. In addition, if the content of the acetone is less than 10 parts by weight, the viscosity is high during the synthesis of the resin is low in the stability of synthesis, if more than 45 parts by weight has a disadvantage that takes a long process to remove acetone after synthesis. If the content of the isocyanate exceeds 15 parts by weight, the hard segment increases and the scratchability is improved, but the soft feel is insufficient, and if less than 5 parts by weight, the curability is insufficient.

In addition, when the NCO of the reaction mixture reaches 2 to 3%, the reaction is terminated, neutralized with an amine, and water is added to disperse the water. If the amount of the remaining NCO is large, the reaction between water and NCO during dispersion As the viscosity may increase or urethane foam may be formed, the reaction is terminated when the NCO is 2 to 3%. In addition, the water to be added for water dispersion is then added at 40 ° C or less to prevent the remaining NCO% from reacting with the water added during water dispersion.

In addition, the chain extender is not particularly limited, but may be selected from the group consisting of ethylenediamine, hydrazine diethylene diamine and isophoronediamine, and if the content of the chain extender exceeds 10 parts by weight, the viscosity of the chain extender is added. There is a risk that the gel may increase to less than 3 parts by weight, resulting in a lower molecular weight.

3) Preparation of paint composition

The hydroxyl group-containing polyurethane resin and the flexible polyurethane resin prepared by the above-described method may be mixed with the additive at an ratio of 1 to 1.5: 1 and stirred to obtain a water dispersible polyurethane resin composition according to the present invention.                     

When the addition ratio of the two resins is out of the above range, the curing is not properly performed, the scratch resistance is poor or the soft texture is insufficient.

Moreover, the coating composition which concerns on this invention contains an additive with the said resin composition. The additive is not particularly limited, and additives constituting a general polyurethane resin composition known to those skilled in the art may be selectively added. In particular, antifoaming agents, wetting agents, pigments and curing agents may be included.

Antifoaming agent can be used by selecting one or more from the group consisting of BYK 032, BYK 036, BYK 037, mineral oil-based antifoaming agent, HS ANTIFOAMER OSI, SN DEFOAMERVL of Sanofko Corp., and wetting agent BYK Corp. Disperbyk, Disperbyk 184, Disperbyk 191 group consisting of one or more can be selected to use. As a pigment, the pigment (black paste) which disperse | distributed for 1 hour or more after mixing the pigment or pigment normally used with water and a dispersing agent in the ratio of 3: 3 can also be used. The curing agent is an isocyanate-based curing agent may be used by selecting one or more of the group consisting of BYK 333, BYK 306, BYK 337, BYK 2102.

The content in the coating composition is preferably 20 to 30 parts by weight of hydroxyl group-containing polyurethane resin, 20 to 30 parts by weight of flexible polyurethane resin, preferably 0.1 to 1 part by weight of antifoaming agent, 0.1 to 2 parts by weight of wetting agent, and curing agent. 5 to 15 parts by weight, black paste may be included in 5 to 15 parts by weight. In addition, the remainder of the entire paint composition is water.

When the coating composition according to the present invention is used to coat plastic interior materials, such as handles and instrument panels, in a vehicle in a conventional manner, such as spraying, it is possible to minimize the use of solvents that cause environmental problems, and to soften leather textures. It has a texture and has little damage to chemicals or external physical stimuli, so it is possible to obtain a product having excellent physical properties such as water resistance and scratch resistance.

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

Example 1

1) Preparation of Polyester Polyols

20 parts by weight of EG (ethylene glycol, manufactured by Polyol Korea), 15 parts by weight of DEG (diethylene glycol, manufactured by Polyol Korea), 35 parts by weight of adipic acid (manufactured by BASF Korea) in a 5000 ml three-necked flask equipped with a thermometer, 20 parts by weight of isophthalic acid (manufactured by KP Chemical Co., Ltd.) and 0.1 part by weight of Fastcat4102 catalyst (manufactured by Atopina Co., Ltd.) were added thereto, and the reaction was carried out while the temperature was raised in steps of 100 ° C, 150 ° C, 180 ° C and 200 ° C. When the temperature was 180 ° C. or higher, nitrogen gas was supplied to suppress yellowing of the polyester polyol resin. The acid value is measured, and when the acid value is about 2 to 3, the reaction is terminated and cooled.

2) Preparation of hydroxyl-containing polyurethane resin

Polyester polyol and diisocyanate (by Bayer) prepared in the steps of DMPA (manufactured by BASF Korea), NMP (manufactured by BASF Korea), 1) in a 2000 ml three-necked flask equipped with a thermometer ) Was added and the temperature was raised to 90 ° C. After 1 hour, NCO% is measured and when the temperature reaches 0%, the temperature is reduced to 60 ° C. After neutralizing with triethanolamine and maintaining for 30 minutes, water (DIW) is added for 10 minutes and dispersed. When water is added, it goes through a high viscosity state from a low viscosity state, maintains a low viscosity state again, and lowers the temperature to room temperature and filters it with 200mesh.

3) Preparation of Flexible Polyurethane Resin

In a 2000 ml three-necked flask equipped with a thermometer, the polyester polyol prepared in the steps of DMPA (manufactured by BASF Korea), acetone, and isocyanate (manufactured by Bayer), 1) was added at a temperature of 50 ° C. It heated up. NCO% was measured after 2 hours and the temperature was lowered to 40 ° C. if it was within 3%. Thereafter, TEA was added and neutralized. After about 30 minutes, the water was supplied by water (DIW) with high speed agitation at 30 DEG C and dispersed. The stirring speed at this time is 300-400 rpm. After all the water was added, immediately after adding ED, a chain extender, and maintained for about an hour. The acetone was completely removed by fractional distillation while gradually raising the temperature from 50 ° C to 90 ° C.

4) Preparation of paint

According to Table 2, after the water (DIW) was added to the polyurethane resin prepared in step 2) and sufficiently dispersed, a defoaming agent (BYK, BYK037), a humectant (BYK, Disperbyk184), black paste (pigment with water Mixed with a dispersant in a ratio of 1: 3: 1, followed by dispersion treatment for at least one hour). Each time you add each substance, let it stir for more than a certain time. In the state of stirring the mixture of step 2), after adding the mixture of step 3), a curing agent (BYK, WT2102) was added thereto, followed by sufficiently stirring.

The coating composition thus prepared was sprayed onto the specimen and cured at 80 ° C. for 20 minutes, and the paint physical properties are shown in Table 3 below.                     

Comparative Example 1

Except for using a commercially available A662 resin of Ivesia and VTW6430 resin of Solusia, the paint was prepared in the same manner as in the paint preparation method of the embodiment, sprayed on the specimen, cured at 80 ° C. for 20 minutes, and then the paint properties. It is shown in Table 3 below.

Comparative Example 2

Except for using the commercially available Solusia VTW6420 resin and VTW6430 resin, the paint was prepared in the same manner as in the paint preparation method of Example, sprayed on the specimen, cured at 80 ° C. for 20 minutes, and then the paint properties were 3 is shown.

ingredient Hydroxyl-containing polyurethane resin (parts by weight) Flexible polyurethane resin (parts by weight) Polyester polyol 30 15 DMPA 8 3 NMP 15 0 Acetone 0 25 Isocyanate 15 8 Triethylamine 3 3 Ethylenediamine 0 3 DIW 29 43 Total 100 100 Solid content (%) 50 35

ingredient Parts by weight Hydroxyl-containing polyurethane resin 33.2 Flexible polyurethane resin 22.9 DIW 18 Antifoam 0.3 Wetting agent 0.5 Black paste 9.6 Hardener 10

Example Comparative Example 1 Comparative Example 2 Initial scratch One 2 3 Solvent resistance 2 One 3 Water resistance One 2 3 Soft texture One 2 3

(1 = excellent, 2 = normal, 3 = bad)

※ Property measurement method

1) Initial Scratch:

Observe the state of the coating immediately after curing at 80 ° C for 20 minutes

Scratches with nails or pins to observe the degree of damage to the coating

2) solvent resistance:

After the film was completely cured, the degree of damage to the film was observed by an alcohol rubbing test. Rubbing the paint in the same number of samples with an alcohol-filled cotton swab, observe the extent of the paint peeling off.

3) Water Resistance:

After complete curing of the coating film, add 1 ml of water (DIW) to observe absorption and appearance.

Compare the extent of the marks and stains on the water.

4) Soft Texture:

Observe the surface of the coating film after complete coating hardening

Rub each hand to evaluate each texture in relative comparison.

As can be seen from the above-described examples and comparative examples, by using the resin composition and the paint composition according to the present invention has a soft texture, such as leather texture, while minimizing the use of solvents that cause environmental problems, The product is excellent in physical properties such as water resistance and scratch resistance since damage to external physical stimuli is small.

Claims (4)

In the manufacturing method of water-dispersible polyurethane resin composition for coating automotive plastic interior materials, 20 to 50 parts by weight of polyester polyol and 5 to 10 parts by weight of dimethylolpropionic acid (hereinafter referred to as DMPA) to 10 to 25 parts by weight of N-methylpyrrolidone (hereinafter referred to as NMP) Dissolving and reacting with 5 to 20 parts by weight of isocyanate to terminate the reaction at the point where NCO becomes 0%, neutralizing with amine, and then dispersing it to provide a hydroxyl group-containing polyurethane resin; 10 to 30 parts by weight of polyester polyol and 2 to 10 parts by weight of DMPA are dissolved in 10 to 45 parts by weight of acetone, and reacted with 5 to 15 parts by weight of isocyanate to terminate the reaction at the point where NCO is 2 to 3%. Neutralizing and then dispersing and reacting by adding 3 to 10 parts by weight of a chain extender, and distilling acetone off completely to provide a flexible polyurethane resin; And Mixing and stirring the hydroxyl group-containing polyurethane resin and the flexible polyurethane resin in a ratio of 1 to 1.5: 1; Method for producing a water-dispersible polyurethane resin composition comprising a. The method of claim 1, wherein the polyester polyol is prepared from a glycol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol and polyethylene glycol has a hydroxyl group at both ends, characterized in that the molecular weight is 1200 to 2000 Method for producing a water-dispersible polyurethane resin composition. The method of claim 1, wherein the isocyanate is at least one selected from the group consisting of isophorone diisocyanate, 1,6-hexamethylene diisocyanate and tetramethyl xyylene diisocyanate. . A water dispersible polyurethane coating composition comprising the water dispersible polyurethane resin composition prepared according to claim 1, an antifoaming agent, a wetting agent, a pigment and a curing agent.