KR102352078B1 - Polyurea coating composition - Google Patents

Abstract

The present invention provides a room temperature curable polyurea coating composition which enables handwork using universal tools and has the same level or more of mechanical properties when being compared to spray type coating. The composition comprises urethane prepolymer as a main material part and polyol and polyaspartic amine as a hardening part.

Description

Polyurea paint composition {POLYUREA COATING COMPOSITION}

The present invention relates to a room temperature curable polyurea coating composition.

Various paints such as epoxy, urethane, polyurea, and inorganic materials are used as flooring materials for buildings. Among them, urethane paint has the advantage of being able to prevent leakage and cracking during contraction and expansion of the building due to its excellent elasticity and elongation, but there is a problem in that tearing or rupture of the coating film is easy to occur due to low tensile strength. On the other hand, epoxy paint has excellent appearance characteristics, chemical resistance, mechanical strength, etc., but has a disadvantage in that the crack resistance of concrete is weak due to low elongation.

In order to solve this problem, a polyurea paint having excellent elongation of urethane and excellent mechanical strength of epoxy has been used. However, since the conventional polyurea paint is of a super-fast curing type, it is difficult to form a smooth appearance, dust is generated during coating, and a problem occurs in the recoating interval. In addition, since the paint is spray-type, it is necessary to use dedicated equipment for high temperature and high pressure or low temperature and low pressure, so it is impossible to construct in a small section, and there are restrictions in application such as deterioration of workability. Various technologies have been developed to improve the disadvantages of the conventional polyurea paints.

For example, Patent No. 10-1372812 discloses a polyurea paint composed of a base comprising isophorone diisocyanate (IPDI) or hexamethylene diisocyanate (HDI) and a curing agent comprising aspartic amine. The polyurea paint can be done manually, and has excellent non-yellowing properties and pot life compared to spray-type polyurea paints, but has short pot life compared to urethane paints, low tensile strength compared to spray-type urea paints, and is expensive. . As another example, Patent No. 10-1484986 discloses a polyurea paint composed of a main agent including HDI-TRIMER having a high NCO% content and a curing agent including aspartic amine. The paint has excellent mechanical properties such as strength, but has disadvantages such as low elongation and high price.

The present invention provides a room temperature curable polyurea paint composition that can be manually operated using a general-purpose tool and has mechanical properties equal to or greater than that of a spray-type paint.

The present invention provides a polyurea coating composition comprising a main part comprising a urethane prepolymer produced by reaction of two or more isocyanates with a polyol, and a curing agent part comprising a polyol and polyaspartic amine.

Since the polyurea coating composition of the present invention has a long pot life and can be manually operated using a general-purpose tool (eg, a rake, a roller, etc.), a coating film exhibiting excellent adhesion without generating dust can be formed. In addition, the polyurea coating composition according to the present invention has excellent coating workability and has mechanical properties equal to or greater than that of a spray-type coating material.

Hereinafter, the present invention will be described in detail. However, it is not limited only by the following content, and each component may be variously modified or selectively mixed as needed. Accordingly, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

The polyurea paint composition according to the present invention includes a main part including a urethane prepolymer produced by reaction of two or more isocyanates with a polyol, and a curing agent part including a polyol and polyaspartic amine.

As used herein, “number average molecular weight” and “weight average molecular weight” are measured by a conventional method known in the art, and may be measured by, for example, a gel permeation chromatograph (GPC) method. Furthermore, the functional group such as "hydroxyl value" is measured by a conventional method known in the art, for example, it can be measured by a method of titration (titration).

<Topic Part>

Urethane prepolymer

The main part of the polyurea paint composition according to the present invention includes a urethane prepolymer produced by reaction of two or more isocyanates with a polyol.

The isocyanate forms a urethane prepolymer through the reaction of an isocyanate group (-NCO) in a molecule and a hydroxyl group (-OH) of a polyol. The isocyanate includes an aromatic diisocyanate and an aliphatic diisocyanate.

Examples of the aromatic diisocyanate include toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, or these Mixtures may be used. As the aliphatic diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, ridine diisocyanate, methylcyclohexane diisocyanate, or a mixture thereof may be used. For example, the isocyanate includes toluene diisocyanate as an aromatic diisocyanate, and includes at least one of isophorone diisocyanate and hexamethylene diisocyanate as an aliphatic diisocyanate.

The isocyanate may include an aromatic diisocyanate and an aliphatic diisocyanate in a weight ratio of 1:1 to 7: 1, for example, 1:1 to 6:1. Since isocyanate reacts with a compound containing active hydrogen in the preparation of polyurea paint, it is important to maintain an appropriate reaction rate in order to secure the workable time of the paint and realize the physical properties of the coating film. It is necessary to mix and use the aliphatic diisocyanate in an appropriate ratio. When the mixing amount of the aromatic diisocyanate is less than the above range, the reaction rate of the isocyanate is slowed due to isocyanate residues generated from the aliphatic diisocyanate, and the reaction and crosslinking are slow when the main agent and the curing agent are mixed, curing and physical properties may be reduced. On the other hand, when the above-mentioned range is exceeded, the cyclic electrons generated from the aromatic diisocyanate increase, thereby increasing the reaction rate of the isocyanate, increasing the reactivity in the paint, and shortening the workable time, thereby reducing workability.

In the present invention, the content of the isocyanate is not particularly limited, and may be, for example, 15 to 45% by weight, for example, 25 to 45% by weight, based on the total weight of the main part. If the content of the isocyanate is less than 15% by weight, hydroxyl groups remain in the urethane prepolymer and the hardness and strength of the coating film may be reduced. This can happen.

As the polyol, a conventional polyol used for polyurethane synthesis in the art may be used without particular limitation. The polyol has a functional group of two or more functional groups, and non-limiting examples include polyether polyol, polyester polyol, polycaprolactone polyol, polybutadiene diol, polytetramethylene ether diol, polypropylene oxide diol, polybutylene oxide diol, triol, etc. The above-mentioned components may be used alone or two or more may be used in combination. In one example, the polyol includes a polyether polyol, such as a polyol of diethylene glycol, 1,3-butylene glycol, or a mixture thereof.

For example, the polyol has a weight average molecular weight (Mw) of 200 to 5,000 g/mol. When the weight average molecular weight falls within the aforementioned range, physical properties such as elongation at break of the waterproof coating film can be adjusted.

In the present invention, the content of the polyol is not particularly limited, and may be, for example, 40 to 70% by weight based on the total weight of the main part. If the content of the polyol is less than 40% by weight, the reaction may not proceed sufficiently and the hardness of the urethane prepolymer may be weakened. can

The urethane prepolymer is produced by the reaction of the above-described polyol with an isocyanate. The method for preparing the urethane prepolymer is not particularly limited, but in consideration of the reactivity of the aromatic isocyanate and the aliphatic isocyanate, the aliphatic isocyanate having the slow reactivity is first reacted with a polyol, and then the aromatic isocyanate can be prepared by reacting the polyol with the polyol. . When a highly reactive aromatic isocyanate is first reacted or an aromatic isocyanate and an aliphatic isocyanate are added and reacted at the same time, the reactivity is not uniform and an addition reaction occurs, or the aliphatic isocyanate remains after the reaction is completed. may appear

For example, the urethane prepolymer may have 6 to 15% isocyanate at the terminal, and a number average molecular weight of 3,000 to 10,000 g/mol. When the isocyanate content of the urethane prepolymer is less than 6%, the reactivity is slowed and the workability is excellent, but the physical properties may be deteriorated and the curing rate may be slow. On the other hand, when the isocyanate content exceeds 15%, the physical properties are excellent, but the reactivity is fast and the workability may be poor. If the number average molecular weight of the urethane prepolymer is less than 3,000 g/mol, solvent resistance and scratch resistance may be reduced because the density of the coating film is lowered. can be

In the present invention, the content of the urethane prepolymer is not particularly limited, and may be, for example, 70 to 100% by weight based on the total weight of the main part.

plasticizer

The main part of the polyurea paint composition according to the present invention may include a plasticizer. The plasticizer serves to adjust the viscosity of the main part and to stably conduct the reaction between the main part and the curing agent part. The plasticizer may be, for example, 1,4-benzenedicarboxylic acid, bis(2-ethylhexyl)ester, hydrogenated hydrocarbon polymers having 6 to 20 carbon atoms, or a mixture thereof.

In the present invention, the content of the plasticizer is not particularly limited, and for example, may be a residual amount satisfying 100% by weight of the main part, and in another example, may be 15% by weight or less based on the total weight of the main part. When the content of the plasticizer exceeds 15% by weight, mechanical properties such as tensile strength may be deteriorated.

solvent

The main part of the polyurea paint composition according to the present invention may contain a solvent. As the solvent, a conventional solvent known in the art may be used.

As the solvent, aromatic hydrocarbon-based compounds such as toluene, xylene, and benzene, n-butyl acetate, mineral spirits, dodecyl phenol, styrene phenol, benzyl alcohol, or mixtures thereof may be used. can In particular, in order to minimize the generation of volatile organic compounds (VOC), one or more VOC exempt solvents may be included. Examples of the VOC exempt solvent include acetone, dimethyl carbonate, and the like. For example, the solvent may include acetone, xylene, dimethyl carbonate, kerosene, or a mixture thereof.

In the present invention, the content of the solvent is not particularly limited, and for example, may be a remaining amount satisfying 100% by weight of the main part, and as another example, may be 15% by weight or less based on the total weight of the main part. When the content of the solvent exceeds 15% by weight, the viscosity is lowered, which is advantageous for workability, but the dry coating film may be softened.

<hardener part>

polyol

The curing agent part of the polyurea paint composition according to the present invention includes a polyol. The polyol has two or more functional groups, and non-limiting examples include polyether polyol, polyester polyol, polycaprolactone polyol, polybutadiene diol, polytetramethylene ether diol, polypropylene oxide diol, polybutylene oxide diol, triol, etc. The above-mentioned components may be used alone or two or more may be used in combination. For example, the polyol may include polyoxypropylene glycol.

The polyol may have a weight average molecular weight (Mw) of 200 to 5,000 g/mol, and a hydroxyl value of 33 to 700 mgKOH/g. When the weight average molecular weight of the polyol is less than 200 g/mol, the reactivity is high, curing is accelerated, and workability may be deteriorated. have.

For example, the polyol has 2 to 3 functional groups, a weight average molecular weight of 200 to 4,000 g/mol, a hydroxyl value of 40 to 560 mgKOH/g, polyoxypropylene glycol and 3 functional groups, and a weight average molecular weight of 250 to 5,000 g/mol, and may include at least one of polyoxypropylene glycol having a hydroxyl value of 33 to 700.

In the present invention, the content of the polyol is not particularly limited, and may be, for example, 5 to 15% by weight based on the total weight of the curing agent part. When the polyol is used in the above-mentioned content range, it may decrease the speed of surface drying of the coating film.

chain extender

The curing agent part of the polyurea coating composition according to the present invention includes a chain extender. The chain extender plays a role in improving the physical properties of the coating film, such as tensile strength and elongation, by increasing the degree of bonding between each component in the coating composition.

The chain extender includes a polyaspartic amine. The polyaspartic amine may include at least one of a quick-drying polyaspartic amine and a slow-drying polyaspartic amine.

As the fast-drying polyaspartic amine, polyaspartic amine having an amine equivalent weight of 190 to 280 g/eq and having a cycloaliphatic or linear aliphatic type may be used. When the amine equivalent of the fast-drying polyaspartic amine is less than 190 g/eq, the reactivity is fast and workability is reduced, and the elongation rate may be reduced due to the low molecular weight. The physical properties may be deteriorated.

As the free polyaspartic amine, polyaspartic amine having an amine equivalent weight of 285 to 400 g/eq and having a cycloaliphatic or linear aliphatic type may be used. If the amine equivalent of the free polyaspartic amine is less than 285 g/eq, the curing rate may be increased and workability may be deteriorated.

The polyaspartic amine may include quick-drying polyaspartic amine and slow-drying polyaspartic amine in a weight ratio of 3:7 to 7:3, for example, 4:6 to 6:4. When the mixing amount of the quick-drying polyaspartic amine is less than the above range, hardening is slow and workability is excellent, but physical properties such as tensile strength may be deteriorated. .

In the present invention, the content of the polyaspartic amine is not particularly limited, and may be, for example, 40 to 70% by weight, and in another example 40 to 55% by weight, based on the total weight of the curing agent part. When the content of polyaspartic amine is less than 40% by weight, the curing rate is slowed and workability is excellent, but physical properties may be softened.

The chain extender is a benzamine such as 4,4-methylenebis[N-(1-methylpropyl)benzeneamine, ar,ar-diethyl-ar-methylbenzenediamine, etc. may further include. In the present invention, the content of the benzamine is not particularly limited, and may be, for example, 1 to 20% by weight based on the total weight of the curing agent part. When the content of the benzamine falls within the above-described content range, excellent physical properties of the coating film may be exhibited.

additive

The curing agent part of the polyurea coating composition according to the present invention may include additives commonly included in the art, such as a catalyst, a filler, an antifoaming agent, an anti-settling agent, an adhesion promoter, a plasticizer, a dispersing agent, and a color tone agent.

The catalyst hardens unreacted urethane groups to improve drying speed and physical properties. Non-limiting examples of the catalyst include dibutyltin dilaurate, lead±neodecanoate, stenus octoate, potassium acetate, bismuth tris-2-ethyl hexoate, 1,4-diazabicyclo[2.2.2 ]octane, bismuth trioxide, and mixtures thereof.

The filler serves to increase the hardness and tensile strength of the coating film. Non-limiting examples of the filler include calcium carbonate, silica, barium sulfate, and mixtures thereof.

The antifoaming agent serves to enhance the appearance of the coating film by suppressing air bubbles generated during painting, and conventional antifoaming agents known in the art may be used without limitation. As an example, a polysiloxane type antifoaming agent may be used.

The anti-settling agent serves to prevent sedimentation of materials to form a coating film in a uniform property, and conventional ones known in the art may be used without limitation. For example, there are a clay type, a wax type, a urethane polymer type anti-settling agent, and the like.

The adhesion promoter is added to reinforce adhesion to the base surface and the strength of the composition through chemical action between the materials constituting the composition, and is a silane compound such as a conventional silane coupling agent known in the art, water-dispersed polyolefin etc. can be used.

The additive may be included in a content range commonly used in the art, for example, may be included in an amount of 0.1 to 50% by weight based on the total weight of the curing agent part.

The polyurea paint composition of the present invention may be prepared according to a conventional method known in the art, and for example, it may be prepared by configuring the main part and the curing agent part of the above-described composition, respectively, and then mixing them in a specific ratio. For example, in the polyurea coating composition, the main part and the curing agent part are mixed in a weight ratio of 1 to 1.6:1. If the content of the main part to the curing agent is less than the above range, foaming phenomenon and cracks in the coating film may occur.

Since the polyurea paint composition according to the present invention has a long pot life and can be manually operated using a general-purpose tool (eg, a rake, roller, etc.), it is possible to form a coating film exhibiting excellent adhesion without generating dust. In addition, the polyurea coating composition of the present invention has excellent coating workability and has mechanical properties equal to or greater than that of a spray-type coating material. Since the polyurea paint composition of the present invention has excellent tensile strength and elongation, it is possible to supplement the weak crack resistance of the epoxy-based flooring material and secure better durability than the urethane-based resin. Therefore, the polyurea paint composition of the present invention can be applied as an interior/exterior parking lot flooring material requiring long-term durability, including the roof or water tank of a building requiring waterproof performance, but is not particularly limited thereto, and various process steps and applicable to the intended use.

For example, the polyurea paint composition according to the present invention may be applied in a medium degree in a coating method for waterproof construction. For example, in a coating method including a urethane-based undercoat coating, a urethane intermediate coating, a polyurea intermediate coating, and a urethane-based top coating coating, it can be used as a polyurea intermediate coating. The urethane-based topcoat may include polyethylene powder. According to the above coating method, it is possible to obtain a coating film having excellent work efficiency and anti-slip performance.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are provided to help the understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

[Production Example 1]

According to Table 1, isophorone diisocyanate (EVONIK), propylene glycol (molecular weight 2,000 to 3,000, KPX) and 1,3-butylene glycol were added, and stirred at 90 ° C. at 200 to 300 rpm and reacted for 4 hours. (1 step reaction). After lowering the temperature to 60 ° C., toluene diisocyanate (OCI), propylene glycol (molecular weight 2,000 to 3,000, KPX) and 1,3-butylene glycol are added to the mixing vessel, and stirred at 80 ° C. at 200 to 300 rpm and reacted for 4 hours (two-step reaction). Hexamethylene diisocyanate (CORONATE HX, NIPPON POLYUREATHANE) was added to the mixing vessel and stirred at 1,000 rpm for 30 minutes or more, thereby preparing a urethane prepolymer of Preparation Example 1. Each component and content used in the preparation is shown in Table 1 below. However, the content of the polyol shown in Table 1 is the total weight of the polyol used in the first-step reaction and the second-step reaction, and 50% of each was used in the first-step reaction and the second-step reaction.

[Preparation Example 2-9]

Except according to the composition of Table 1, the urethane prepolymer of Preparation Example 2-9 was prepared in the same manner as in Preparation Example 1.

[Comparative Preparation Example 1-4]

Except according to the composition of Table 2, a urethane prepolymer of Comparative Preparation Example 1-4 was prepared in the same manner as in Preparation Example 1.

[Example 1-9]

Using each of the prepolymers prepared in Preparation Examples 1-9, the main part and the curing agent part were constituted according to the compositions shown in Table 3 below, and the polyurea coating compositions of Examples 1-9 were prepared by mixing them.

[Comparative Example 1-4]

The polyurea coating composition of Comparative Example 1-4 was prepared by using each of the prepolymers prepared in Comparative Preparation Example 1-4, composing a main part and a curing agent part according to the composition shown in Table 4, and mixing them.

Plasticizer: Hydrogenated Hydrocarbon Polymer N-50

Solvent: Xylene

Polyol: polyester polyol (molecular weight 3,000, KPX)

Polyaspartic amine 1: Quick-drying polyaspartic amine (FEISPARATIC F420, FEIYANG, amine equivalent 275 g/eq)

Polyaspartic amine 2: Quick-drying polyaspartic amine (JY-MF 201 Jinyangyang, amine equivalent 250 g/eq)

Polyaspartic amine 3: fat polyaspartic amine (FEISPARATIC F2850, FEIYANG, amine equivalent 290 g/eq)

DETDA: Diethyltoluenediamine (ALBERMAL)

Benzeneamine: 4,4-methylenebis[N-(1-methylpropyl)benzeneamine (polylik4200, ALBERMAL)

Extender pigment: calcium carbonate (average particle size 5 ㎛, OMYA)

Defoamer: BYK-066N

Dispersant: NUSPER-657

Tint: TiO ₂

Catalyst: A-9 (Zinyangseong)

[Experimental example]

The polyurea coating composition of each of the Examples and Comparative Examples was applied to a release paper to form a coating film having a thickness of 2 mm, and demolded after at least 7 days to prepare a specimen. The physical properties of the coating films of each specimen were measured by the following method, and the results are shown in Tables 5 and 6, respectively.

swelling

Each specimen was cured at 60 °C x 60% to check whether the film swells.

housekeeping time

About 80% by volume of the coating composition of each Example and Comparative Example was put in a tin can, and then measured with a Brookfield viscometer at 25 °C, #6, 10 rpm, Max. Pot life was measured under the condition of 10,0000 cps.

curing dry

After a certain amount of the coating composition of each Example and Comparative Example was applied on an MDF panel (150 x 300 mm), the degree of curing according to time was observed.

The tensile strength

After each specimen was left in the standard state for 1 hour or more, the specimen was attached to a tensile tester so that the interdigitation interval was 60 mm, and the specimen was pulled at a tensile rate of 500 mm/min until the specimen was broken. Tensile strength was checked by reading the maximum load on an automatically recorded chart paper and using the average of three values.

elongation

After each specimen was left in the standard state for 1 hour or more, the specimen was attached to a tensile tester so that the interdigitation interval was 60 mm, and the specimen was pulled at a tensile rate of 500 mm/min until the specimen was broken. The distance until the upper and lower parts of the coating film were broken was measured.

tear strength

After each specimen was left in the standard state for 1 hour or more, the specimen was attached to a tensile tester so that the interdigitation interval was 60 mm, and the specimen was pulled at a tensile rate of 500 mm/min until the specimen was broken. The tear strength was checked by reading the maximum load on the automatically recorded chart paper and using the average of three values.

Rake workability

The workability of the coating compositions of each Example and Comparative Example was confirmed by using a rubber wrench.

leveling

Leveling of the coating composition of each Example and Comparative Example was observed using SAG METER and RAKE.

defoaming

After the coating composition of each Example and Comparative Example was spread on a glass plate (300 cm x 600 cm) with a RAKE, the number of bubbles was measured.

◎: Very good, ○: Excellent, △: Good, X: Poor

◎: Very good, ○: Excellent, △: Good, X: Poor

As shown in Tables 5 and 6, the polyurea paint composition of Examples 1-9 using the urethane prepolymer of Preparation Examples 1-9 according to the present invention exhibited excellent physical properties in all measurement items. On the other hand, the polyurea paint composition of Comparative Example 1 using the urethane prepolymer of Comparative Preparation Example 1 using only aromatic isocyanate had a very short pot life and poor workability. On the other hand, the polyurea paint composition of Comparative Example 2 using the urethane prepolymer of Comparative Preparation Example 2 using only aliphatic isocyanate had a very long drying time, and showed poor tensile strength and workability. In addition, the polyurea paint compositions of Comparative Examples 3 and 4 using the urethane prepolymers of Comparative Preparation Examples 3 and 4 that were mixed with aromatic isocyanate and aliphatic isocyanate, but used outside the compounding ratio according to the present invention, had a lot of swelling and drying time This length was found to be poor, and the coating film strength and workability were poor.

Claims (8)

A main part comprising a urethane prepolymer produced by reaction of two or more isocyanates with a polyol and a curing agent part comprising a polyol and polyaspartic amine,
The polyurea paint composition wherein the isocyanate comprises an aromatic diisocyanate and an aliphatic diisocyanate in a weight ratio of 1:1 to 7: 1. The polyurea paint composition according to claim 1, wherein the aromatic diisocyanate comprises toluene diisocyanate, and the aliphatic diisocyanate comprises at least one of isophorone diisocyanate and hexamethylene diisocyanate. The polyurea coating composition according to claim 1, wherein the urethane prepolymer has 6 to 15% isocyanate at the terminal and a number average molecular weight of 3,000 to 10,000 g/mol. The polyurea paint composition according to claim 1, wherein the polyaspartic amine comprises at least one of a quick-drying polyaspartic amine and a quick-drying polyaspartic amine. The polyurea paint composition according to claim 4, wherein the quick-drying polyaspartic amine has an amine equivalent of 190 to 280 g/eq, and the quick-drying polyaspartic amine has an amine equivalent of 285 to 400 g/eq. The polyurea paint composition according to claim 1, wherein the polyaspartic amine contains quick-drying polyaspartic amine and slow-drying polyaspartic amine in a weight ratio of 4:6 to 6:4. The polyurea paint composition according to claim 1, further comprising benzamine. A method of coating a structure comprising the steps of coating a urethane undercoat composition, coating a urethane intermediate coating composition, coating a polyurea intermediate coating composition, and coating a urethane topcoat composition,
The method of coating a structure wherein the polyurea intermediate coating composition is the polyurea coating composition of any one of claims 1 to 7.