KR20020068572A - Method Of Preparing Urethane Acrylate Oligomer And UV-curable Coating Composition Including The Same - Google Patents

Abstract

PURPOSE: A method for preparing a urethane acrylate oligomer and a UV curing coating composition containing the oligomer are provided, to improve the hardness and the flexibility compared with that of a hard coating agent. CONSTITUTION: The method comprises the steps of reacting 0.9-1 equivalent of aliphatic diisocyanate, 1 equivalent of pentaerythritol and ester reaction compound of acrylic acid in the presence of a metal catalyst and a vinyl-based polymerization inhibitor; and diluting the product with 10-70 wt% of OH-containing single functional group vinyl-based monomer. Preferably the aliphatic diisocyanate is selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and norbornane diisocyanate. The coating composition comprises 10-70 wt% of the urethane acrylate oligomer; 10-70 wt% of a polyfunctional vinyl-based monomer; 1-10 wt% of a photoinitiator; and 0.1-10 wt% of a surface controlling agent.

Description

Method of preparing urethane acrylate oligomer and UV curable coating composition comprising same TECHNICAL FIELD

The present invention relates to a method for preparing a urethane acrylate oligomer and an ultraviolet curable coating film composition containing the same. More specifically, the wear resistance of a molded article is coated on a molding made of a thermoplastic resin such as polycarbonate, acrylonitrile butadiene styrene and acrylic. The present invention relates to an ultraviolet curable coating film composition capable of improving adhesion, heat resistance, and flexibility.

The coating composition for protective coating of the conventional thermoplastic resin molded article is a coating film using a thermosetting coating film composition using an acrylic lacquer, a two-component acrylic urethane, an organosilane, a thermosetting coating composition using a melamine resin-based composition, or an ultraviolet curing polyfunctional acrylate mixture. The composition was used, but gradually the productivity and high wear resistance quality is required, and recently, a coating film composition using an ultraviolet curable urethane acrylate system, an ultraviolet curable silicone hard coating agent and a thermosetting silicone hard coating agent have been used.

The UV curable multifunctional acrylate coating composition disclosed in Korean Patent No. 10-0199496 has improved abrasion resistance and hardness by using acrylates having a large number of functional groups in order to improve wear resistance and hardness, but in terms of impact resistance, adhesion, flexibility, heat resistance, etc. Problems of poor quality have occurred.

In Japanese Patent Application Laid-Open No. 5-214044, polyethylene glycol-based acrylates, polypropylene-based diacrylates, and tri- or more-functional vinyl monomers are mixed to improve adhesion, flexibility, and heat resistance. Abrasion resistance and hardness showed a problem that does not meet the required physical properties, causing a problem in durability.

U.S. Patent Nos. 4,299,746 and 3,986,997 have used UV-curable silicone hardcoats using condensates of colloidal silica and alkoxy silanes, but problems such as flexibility, impact resistance, and poor workability have arisen.

An object of the present invention is to provide a method for producing a multifunctional urethane acrylate oligomer in order to solve the problems of the prior art.

Another object of the present invention is to provide an ultraviolet curable coating composition having excellent abrasion resistance, adhesion, hardness, heat resistance and long-term durability by including a urethane acrylate oligomer prepared according to the above method.

In order to achieve the above object, in the present invention

Reacting a mixture of 0.9 to 1 equivalent of aliphatic diisocyanate and 1 equivalent of pentaerythritol with an ester reaction compound of acrylic acid in the presence of a polymerization inhibitor of a metal catalyst and a vinyl compound; And

It provides a method for producing a urethane acrylate oligomer comprising the step of diluting by adding a 10-70% by weight hydroxyl group-containing monofunctional vinyl monomer to the reactant obtained.

Another object of the present invention described above is 10 to 70% by weight of urethane acrylate oligomer prepared according to the above method, 70 to 10% by weight of polyfunctional vinyl monomer, 1 to 10% by weight of photoinitiator and 0.1 to 10% of surface control additive It is achieved by the ultraviolet curable coating film composition containing%.

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

First, the type of each component applied for the preparation of the urethane acrylate oligomer and the amount of use thereof will be described.

Aliphatic diisocyanates which may preferably be used include, for example, at least one compound selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and norbornane diisocyanate.

In the present invention, a mixture of pentaerythritol diacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate can be preferably used as the ester reaction compound of pentaerythritol and acrylic acid used in the reaction with diisocyanate. By the way, it is more preferable that there are few pentaerythritol diacrylates and relatively many pentaerythritol triacrylates and tetraacrylates.

This is to increase the number of functional groups of these reactants as much as possible to increase the hardness of the coating film by making the average functional groups 5 or more, but to ensure the production stability of the urethane acrylate. If the diacrylate is too much, the molecular weight becomes too large during the reaction, there is a risk of gelation and the viscosity is too high, which adversely affects the workability during painting. From this point of view, the proportion of each monomer is preferably 5% by weight or less of diacrylate, 50% by weight or more of triacrylate, and the remaining amount is tetraacrylate.

The mixing ratio of the diisocyanate compound and the ester compound may be 1: 1 in an equivalent ratio, but 0.9 to 1: 1 in an equivalent ratio so that no diisocyanate remains.

Tin-based compounds may be used as the metal catalyst to be applied, and in particular, dibutyl tin dilaurate is most preferred. It may be used as long as the amount is small enough to play a role as a catalyst, but it is preferable to use about 200ppm with respect to the amount of starting material except reactive diluent.

In addition, as the polymerization inhibitor, hydroquinone, p-benzoquinone, t-butylhydroquinone, and mixtures thereof may be used. Its amount is preferably about 200-600ppm of the total amount including the reactive diluent.

When the ester reaction compound of the aliphatic diisocyanate and pentaerythritol with acrylic acid is reacted in the presence of a metal catalyst and a polymerization inhibitor, the end point of the reaction is when the isocyanate (NCO) peak disappears, and as a result of repeated experiments of the present inventors, It is thought that the reaction is usually completed when it is carried out for 4 to 8 hours in the temperature range of ℃.

In the present invention, as the hydroxyl group-containing monofunctional vinyl monomer which is a reactive diluent, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, and the like may be applied, and two or more kinds thereof may be mixed and used.

These hydroxyl group-containing monofunctional vinyl monomers are an important factor that prevents brittleness due to excessive crosslinking density of the cured coating film when the polyfunctional urethane acrylate is used alone during UV curing, and is a hydroxyl group-containing monofunctional vinyl system monomer. The monomer is sandwiched between the polyfunctional urethane acrylates to ensure the flexibility of the coating film.

The amount of the hydroxyl group-containing monofunctional vinyl monomer may be 10 to 70% by weight based on the total amount of reactants of the diisocyanate, pentaerythritol and acrylic acid ester compound. If the amount thereof is less than 10% by weight, the adhesion of the coating film may be poor, and when the amount thereof is more than 70% by weight, the coating film may be inferior in curability. Therefore, the amount thereof is to be in the above range, more preferably in the range of 10 to 50% by weight.

In consideration of the conditions given above, a polyfunctional urethane acrylate oligomer applicable to an ultraviolet curable coating film composition is prepared, and the coating film composition is prepared by using the same. For this purpose, the type of each component and the amount of use thereof will be described.

UV-curable coating composition according to the present invention is 10 to 70% by weight of the urethane acrylate oligomer prepared according to the above-described method, 70 to 10% by weight of polyfunctional vinyl monomer, 1 to 10% by weight of photoinitiator and 0.1 to 10 additive for surface control It comprises by weight percent.

The polyfunctional vinyl monomer used in the present invention reacts with the urethane acrylate oligomer upon ultraviolet curing, affecting the hardness, abrasion resistance, and other performance of the coating film, and mainly acrylic acid or methacrylic acid esters are used.

Specifically, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, dipentaerythritol pentaacrylate, dipenta At least one compound selected from the group consisting of erythritol hexaacrylate and pentaerythritol tetraacrylate can be preferably used. More preferably, in such a compound, the trifunctional or more than trifunctional acrylate is used 1 type or in mixture of 2 or more types.

10-70% by weight of urethane acrylate oligomer and 70-10% by weight of polyfunctional vinyl monomer are used as main components for the production of the coating composition. These are used in the ratio of 1: 7-7: 1 by weight ratio, and it is a limited range in consideration of the hardness, abrasion resistance, adhesiveness, the viscosity of a composition, etc. of the coating film obtained.

If the amount of the urethane acrylate oligomer is less than 10% by weight, the hardness, abrasion resistance, and adhesion of the coating film are inferior. If the amount exceeds 70% by weight, the viscosity of the composition is high and the paintability is poor. Therefore, it is preferable to use 10-70 wt% in consideration of the performance and viscosity of the coating film. Since the amount of the polyfunctional vinyl monomer is inversely proportional to the amount of the urethane acrylate oligomer, when the amount of the polyfunctional vinyl monomer is out of the above range, the amount of the urethane acrylate oligomer may also be relatively out of the given range, resulting in the aforementioned side effects.

The photoinitiator used in the present invention may be a benzophenone compound, benzyl dimetal ketal compound, acetophenone compound, anthraquinone compound, benzyl ketal compound, mixtures thereof, and the like. Methoxy-2-phenyl acetophenone, 1-hydroxycyclohexyl phenyl ketone, 1-hydroxy dimethyl phenyl ketone and the like can be preferably used. It is preferable to use 1-10% by weight of the total amount of the coating film composition.

The surface control additive is a material used for improving slip and leveling of the coating film, and a silicone compound, a silicone-modified polyacrylate compound, and the like may be used. Specifically, BYK-306, 310 TEGO RAD-2500, wire diameter-UCB EB-350, etc. are mentioned. The amount of the additive for controlling the surface may be used in the range of 0.1 -10% by weight of the total amount of the coating film composition and may be used within the range that does not adversely affect the coating performance.

The coating composition of the present invention may further include a quencher for the matting effect of the cured coating film. As the matting agent, silica powder and synthetic polymer powder such as polyethylene, polypropylene, and polyolefin can be used. Specifically, SYLOID 244, OK-412, MZUKASIL P-802Y and LANCO WAX PP-1362D, TF-1778, TF- 1780, etc. are mentioned. Its use amount is in the range that does not affect the coating film performance, but it is preferably used at 10% by weight or less.

After the ultraviolet curable coating composition is prepared to satisfy the above conditions, it is coated and applied to a thermoplastic resin molded article made of polycarbonate, acrylonitrile butadiene styrene, acrylic, and the like. The method of operation can be applied to spray, dipping, roll coating, etc., which can be selected according to the shape, material and thickness of the molding. In addition, an appropriate amount of an organic solvent may be added and mixed according to a working method. Examples of the organic solvent may include an acetate compound, a ketone compound, an aromatic compound, or a mixture thereof. Its use amount can be used in the weight ratio of 3: 1-1: 3 with respect to an ultraviolet curable coating film composition.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples.

<Example 1>

In a four-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirrer, 1030 g of a mixture of 3 wt% pentaerythritol diacrylate, 52 wt% pentaerythritol triacrylate and 45 wt% pentaerythritol tetraacrylate was added thereto. To this, 200 ppm of dibutyldine dilaurate and 400 ppm of t-butyl hydroquinone as a vinyl group polymerization inhibitor were added. It heated up at 70 degreeC, and dripping 2 equivalents of isophorone diisocyanate for 1 hour, and then it hold | maintained for 6 hours. After confirming that there was no NCO peak by infrared spectrophotometry (IR), it cooled to 60 degreeC and diluted with 537.3 g of 2-hydroxyethyl methacrylate, and prepared the urethane acrylate oligomer.

<Example 2>

The urethane acrylate oligomer was prepared in the same manner as in Example 1 except that hexamethylene diisocyanate was used in the same equivalent amount instead of isophorone diisocyanate.

<Example 3>

The urethane acrylate oligomer was prepared in the same manner as in Example 1, except that 417.7 g of 2-hydroxypropyl acrylate was used instead of 2-hydroxyethyl methacrylate.

Comparative Example 1

The urethane acrylate oligomer was prepared in the same manner as in Example 1 except for 2-hydroxyethyl methacrylate.

Comparative Example 2

The urethane acrylate oligomer was prepared in the same manner as in Example 1 except that toluene diisocyanate was used in the same amount instead of isophorone diisocyanate and except for 2-hydroxyethyl methacrylate.

<Example 4>

55% by weight of the urethane acrylate oligomer synthesized in Example 1, 36% by weight of dipentaerythritol hexaacrylate, 8% by weight of 1-hydroxycyclohexyl phenyl ketone, an acetophenone-based photoinitiator, and 1% by weight of an additive To prepare an ultraviolet curable coating film composition.

Example 5

50% by weight of the urethane acrylate oligomer synthesized in Example 2, 31% by weight of pentaerythritol triacrylate, 10% by weight of dipentaerythritol hexaacrylate, 8% by weight of 1-hydroxydimethyl phenyl ketone as an acetophenone-based photoinitiator and additives 1 weight% was mixed uniformly, and the ultraviolet curable coating film composition was produced.

<Example 6>

60% by weight of the urethane acrylate oligomer synthesized in Example 3, 31% by weight of dipentaerythritol hexaacrylate, 8% by weight of 1-hydroxydimethyl phenyl ketone, an acetophenone-based photoinitiator, and 1% by weight of an additive for surface control To prepare an ultraviolet curable coating film composition.

<Comparative Example 4>

50% by weight of the urethane acrylate oligomer synthesized in Comparative Example 1, 30% by weight of pentaerythritol triacrylate, 11% by weight of trimethanol propane triacrylate, 8% by weight of 1-hydroxycyclohexyl phenyl ketone as an acetophenone-based photoinitiator And 1 weight% of the additives were uniformly mixed to prepare an ultraviolet curable coating film composition.

Comparative Example 5

50% by weight of the urethane acrylate oligomer synthesized in Comparative Example 2, 25% by weight of pentaerythritol triacrylate, 14% by weight of trimethylolpropane triacrylate, 10% by weight of 1-hydroxycyclohexyl phenyl ketone as an acetophenone-based photoinitiator And 1 weight% of the additives were uniformly mixed to prepare an ultraviolet curable coating film composition.

In order to perform the physical property test, the UV curable coating composition prepared in Examples and Comparative Examples was diluted to 50% by weight with a 1: 1 mixed solvent of ethyl acetate / butyl acetate, and then directly to a polymethyl methacrylate (PMMA) material, which is an acryl material. And after coating the coating with a metallic intermediate material to a thickness of 10㎛ by spraying work and compared the physical properties after UV curing through an ultraviolet curing machine. The curing conditions were completely cured by irradiating two high-pressure mercury lamps of 80 W / cm at an irradiation distance of 10 cm (800 to 1200mj / cm ² ).

Physical property test results are shown in Table 1. The results are shown by averaging the results obtained when directly coated on the material and when coated on the specimen coated with the metallic intermediate material.

Example 4 Example 5 Example 6 Comparative Example 4 Comparative Example 5 Hardness 5H 4H 4H 2H 3H Adhesion 100/100 100/100 100/100 55/100 80/100 Wear resistance ○ ○ ○ △ △ Alcohol resistance ○ ○ ○ ○ ○ Heat-resistant ○ ○ ○ △ × Hot water resistance ○ ○ ○ △ △ Solvent resistance ○ ○ ○ ○ ○ Scratch resistance ○ ○ ○ △ ○ flexibility ○ ○ ○ △ ×

In Table 1, ○ is excellent, △ is usually, × means poor.

The physical property test for each item was performed by the following method.

1) Hardness: measuring the film hardness by the ASTM D 3363-74 pencil test

2) Adhesion: Test Method for Adhesion to ASTM D 3359-93

3) Wear resistance: Appearance inspection after Taber's M 503 Abrasion Tester CS-10, 500g, 100 turns

4) Alcohol resistance: gloss measurement after 24 hours immersion in a mixture of methanol, isopropyl alcohol and n-butanol

5) Heat resistance: -20 ℃ (1hr) ~ room temperature (1hr) ~ 60 ℃ (1hr) / 3 repetition

6) Hot water resistance: Determination of adhesion after 24 hours immersion in 40 ℃ hot water

7) Solvent resistance: gloss measurement after 1 hour deposition of methyl ethyl ketone

8) Scratch resistance: Rubbing 3 times with steel wool to confirm scratch

9) Flexibility: Fold the cured film to check the degree of chipping

As can be seen from the above results, the UV curable coating composition of the present invention containing the urethane acrylate oligomer according to the present invention has various properties such as abrasion resistance, adhesion, heat resistance, flexibility, etc., when used for the protection of thermoplastic acrylic resins and metallic intermediates. It can be seen that the item shows excellent performance.

The coating composition of the present invention as described above is to perform the role of protecting the object from the external environment by giving a wear resistance, adhesion, weather resistance, etc. to the injection and extrudates, PC, acrylic parts which are the subject. Specifically, it can be applied for the one-coat of the window of a mobile phone, PMMA, PC, ABS injection molded products, and extrusion molded products.

According to the present invention as described above can be prepared UV-curable urethane acrylate oligomer excellent in physical properties such as abrasion resistance, adhesion, heat resistance, etc., the coating composition containing it has a high hardness and flexibility compared to the conventional hard coating agent At the same time, it satisfies and exhibits excellent performance as a surface hardness reinforcing material of plastics, particularly acrylic resin molded articles.

Although the present invention has been described above according to an embodiment of the present invention, it will be apparent to those skilled in the art that various modifications may be made without departing from the spirit of the present invention.

Claims (14)

Reacting a mixture of 0.9 to 1 equivalent of aliphatic diisocyanate and 1 equivalent of pentaerythritol with an ester reaction compound of acrylic acid in the presence of a polymerization inhibitor of a metal catalyst and a vinyl compound; And A method for producing a urethane acrylate oligomer comprising the step of adding and diluting 10 to 70% by weight of a hydroxyl group-containing monofunctional vinyl monomer to the mixture obtained. The process according to claim 1, wherein the aliphatic diisocyanate is at least one compound selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and norbornane diisocyanate. The method according to claim 1, wherein the ester reaction compound of pentaerythritol and acrylic acid is a mixture of pentaerythritol diacrylate, pentaerythritol triacrylate and pentaerythritol tetraacrylate. The method of claim 1, wherein the ester reaction compound of pentaerythritol and acrylic acid is a mixture of 5 wt% or less pentaerythritol diacrylate, 50 wt% or more pentaerythritol triacrylate, and a balance of pentaerythritol tetraacrylate. Manufacturing method The production method according to claim 1, wherein the metal catalyst is a tin compound. The method of claim 1, wherein the polymerization inhibitor is at least one compound selected from the group consisting of hydroquinone, p-benzoquinone and t-butylhydroquinone. The method according to claim 1, wherein the reaction of the aliphatic diisocyanate and the ester reaction compound of pentaerythritol with acrylic acid is carried out for 4 to 8 hours in a temperature range of 60 to 80 ° C. The method of claim 1, wherein the hydroxyl group-containing monofunctional vinyl monomer is 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4 -At least one compound selected from the group consisting of hydroxybutyl acrylate and 4-hydroxybutyl methacrylate. Ultraviolet curing type comprising 10 to 70% by weight of urethane acrylate oligomer prepared according to the method of claim 1, 70 to 10% by weight of polyfunctional vinyl monomer, 1 to 10% by weight of photoinitiator and 0.1 to 10% by weight of surface control additive Coating composition. The method of claim 9, wherein the polyfunctional vinyl monomer is 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, A coating film composition, characterized in that at least one compound selected from the group consisting of dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate and pentaerythritol tetraacrylate. The coating composition according to claim 9, wherein the photoinitiator is at least one selected from the group consisting of benzophenone compounds, benzyl dimetal ketal compounds, acetophenone compounds, anthraquinone compounds, and benzyl ketal compounds. The coating composition of claim 9, wherein the surface control additive is a silicone compound, a silicone-modified polyacrylate compound, or a mixture thereof. 10. The coating composition of claim 9 further comprising up to 10% by weight of a matting agent. 10. The coating composition according to claim 9, further comprising acetate, ketone, and aromatic organic solvents in a total ratio of the coating composition and the weight ratio of 3: 1 to 1: 3.