KR101614079B1 - Coating composition with highly hardness polyurea - Google Patents

Abstract

The present invention relates to a high hardness polyurea coating composition, wherein a high hardness polyurea coating composition is prepared by adding a polyetheramine and a super-hard polyol to an isocyanate to improve the elongation percentage and prolong the hardening time It is possible to make a high hardness polyurea coating material free from coating cracks even at a low temperature.

Description

TECHNICAL FIELD [0001] The present invention relates to a high hardness polyurea coating composition,

The present invention relates to a high hardness polyurea coating composition.

Typically, a coating material which forms a urea bond by the reaction of an -NCO- group of an isocyanate and an -NH- group of an amine is called a polyurea coating, which is very rapid and forms a film in a few seconds due to a no catalyst reaction .

 Such a polyurea coating material has been mainly used for increasing the NCO% of isocyanate to increase the urea reactivity with amines in order to increase the hardness of the coating film. Korean Patent Registration No. 10-0993243 discloses a polyurethane-polyurea coating .

 The conventional method of raising the NCO% of isocyanate to increase the urea reactivity with the amine is a method of increasing the hardness due to the abrupt reaction, but it is the standard of the high hardness polyurea of the water pipe type (AWWA C-222 standard) There was a limit to raising the hardness above the Shore 65 D.

That is, when the NCO% of the isocyanate is too high, cracks often occur in the coating film due to the rapid reactivity.

Therefore, there is a need to develop a technique for preventing cracks from occurring in the coating film during the manufacture of the coating material and having physical properties of high hardness.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a coating material composition which is improved in appearance and durability by forming a coating film without cracking even at high hardness.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus and method for controlling the same.

To achieve this object, in one aspect of the present invention, a high hardness polyurea coating composition comprises 100 parts by weight of an isocyanate having an NCO group content of 16 to 20%; 50 to 60 parts by weight of a polyetheramine having a number average molecular weight of 2000, 5 to 10 parts by weight of a polyetheramine having a number average molecular weight of 5,000, 10 to 15 parts by weight of polydiethyltoluenediamine, A curing agent having 10 to 20 parts by weight of a polyether polyol; . ≪ / RTI >

The curing agent may further have 1 to 2 parts by weight of an adhesion promoter, 0.5 to 1 part by weight of a defoaming agent, and 3 to 5 parts by weight of a colored pigment.

Then, the base and curing agent may be mixed in a volume ratio of 1: 1.

In addition, the polyether polyol may have a number average molecular weight of 500.

On the other hand, the adhesion promoter may be at least one selected from the group consisting of gamma-methacryloxypropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and beta- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. (3,4- epoxycyclohexyl) ethyltrimethoysilane).

As described above, the present invention has the following effects.

First, the present invention has the effect of increasing the adhesion of the polyetheramine and the super-hard polyol to isocyanate by supplementing the elongation percentage and increasing the curing time by adding a super-hard polyol.

Second, a high hardness polyurea coating material having no coating crack at low temperature can be produced.

Third, the existing high-hardness type was so hard that the appearance of dust was blown, and when the spray was applied, the smoothness was as bad as the width of the operator when the spray was applied. However, the present invention was based on the finding that a high hardness polyol The reaction time was prolonged, so that the reactivity was slower than that of the polyether amines having amine (-NH-) groups, thereby preventing the possibility of apparent failure.

Fourth, since the existing high hardness type is hard to cure, the polyurea coating is applied on the gun (GUN), and the remaining liquids accumulate continuously. After a certain time, there are problems in the field where the coating gun (GUN) However, in the present invention, the reactivity is extended by adding a high-hardness polyol to the coating material.

That is, since the application is completed within a few seconds before the polyurea liquids accumulate in front of the coating gun, the polyurea liquids do not accumulate at all, and continuous operation is possible.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

The preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings, in which the technical parts already known will be omitted or compressed for simplicity of explanation.

The high hardness polyurea coating material using the high hardness polyol according to one embodiment of the present invention will be described in detail as follows.

First, the present invention relates to a solution prepared by prepolymerizing an isocyanate having a -NCO group, which is a main agent that affects the reactivity and tensile strength of a fast curing type high hardness polyurea coating material using a high hardness polyol, And a curing agent mixture containing a polyether polyol having a small molecular weight and a large number of functional groups capable of forming a polyurea coating film without causing cracks while causing a reaction in the resin.

The content of the NCO group in the prepolymer solution is determined by measuring the tensile strength, hardness, elongation, and reaction rate of the coating film. The prepolymer solution is prepared by mixing 100 parts by weight of an isocyanate having an NCO group content of 16 to 20% The higher the NCO% (i.e., the content of -NCO- group), the higher the hardness, the tensile strength and the reactivity (speed) of the coating film. The lower the content of -NCO- group, the higher the elongation percentage of the coating film and the lower the hardness.

If the content of NCO groups is less than 16%, the hardness of the coating becomes too low to be used as a coating material. When the content of NCO groups exceeds 20%, cracks may occur in the coating film. It is preferable to use a prepolymer solution composed of 16 to 20%.

The curing agent mixture was prepared by mixing 50 to 60 parts by weight of a polyetheramine having a number average molecular weight (hereinafter abbreviated as " molecular weight ") 2,000 which determines the tensile strength and the reaction rate of the polyurea coating, 5 to 10 parts by weight of etheramine and 10 to 15 parts by weight of polydiethyl toluene diamine (10 to 15 parts by weight) which forms a network structure of main chains to determine tensile strength, reactivity and hardness, and -OH group 10 to 20 parts by weight of a polyether polyol having a molecular weight of 500 and 1 to 2 parts by weight of an adhesion promoting agent for increasing the adhesion between the substrate and the surface of the substrate and a defoamer for imparting aesthetic appearance without smudging the surface, And 3 to 5 parts by weight of a colored pigment are added to the reaction vessel to give a color of the coating film, and the mixture is thoroughly stirred at 1,000 to 2,000 rpm for 1 to 2 hours.

When the addition amount of the polyetheramine having a molecular weight of 2,000 to determine the tensile strength and the reaction rate of the polyurea coating in the curing agent mixture is less than 50 parts by weight, the tensile strength of the coating film decreases. When the amount exceeds 60 parts by weight, Since the coating film may be formed before leveling and the adhesion may be abruptly lowered, it is preferably added within the range of 50 to 60 parts by weight.

When the addition amount of the polyetheramine having a molecular weight of 5,000 to determine the tear strength of the polyurea coating film in the curing agent mixture is less than 5 parts by weight, the coating tears easily. When the addition amount exceeds 10 parts by weight, It may be cracked. Therefore, it is preferable to add it within the range of 5 to 10 parts by weight.

When the addition amount of polydiethyltoluenediamine, which determines the tensile strength, reactivity and hardness of the polyurea coating film in the curing agent mixture, is less than 10 parts by weight, the reactivity is slow and the tensile strength and hardness are decreased, and more than 15 parts by weight The adhesion with the surface is remarkably deteriorated due to the rapid reactivity. Therefore, it is preferable to add it within the range of 10 to 15 parts by weight.

When the addition amount of the polyether polyol having a molecular weight of 500 for imparting the elasticity of the polyurea coating film in the curing agent mixture is less than 10 parts by weight, cracks occur due to the rapid reactivity in which the coating film is formed in a few seconds. When the amount is more than 20 parts by weight, However, since the coating is too soft to obtain hardness of Shore 65 D or higher which is AWWA (American Waterworks Association) C-222 standard, it is preferably added within 10 to 20 parts by weight.

Adhesion promoting agents for enhancing the adhesion between the polyurea coating film and the substrate surface in the curing agent mixture include Gamma-methacryloxypropyltrimethoxysilane, gamma-glycidoxypropylmethoxysilane (Gamma- glycidoxypropyltrimethoxysilane and beta - (3,4-epoxycyclohexyl) ethyltrimethoxysilane. If the addition amount of the adhesion promoter is less than 1 part by weight, When the adhesive strength is lowered and more than 2 parts by weight, there is a possibility that coating film stickiness remains, so it is preferably added within 1 to 2 parts by weight.

The antifoaming agent in the curing agent mixture improves the appearance and abrasion resistance of the coating film by removing bubbles on the surface of the polyurea coating film, and it is preferable to select one of silicone and non-silicone systems.

If the weight of the defoamer is less than 0.5 parts by weight, it is difficult to remove the bubbles in the solution, so that a large number of bubble marks appear on the outer surface, resulting in poor appearance. When the amount exceeds 1 part by weight, The interlayer adhesive force may appear to be defective. Therefore, it is preferable to add it within the range of 0.5 to 1 part by weight.

The colored pigments representing the color of the polyurea coating in the curing agent mixture may be selected from one or more of colored pigments as organic or inorganic pigments. If the amount of the colored pigment is less than 3 parts by weight, the polyurea coating film may have poor hiding power with respect to the base paper surface, and the surface of the polyurea coating may be poor. If the amount of the pigment exceeds 5 parts by weight, the viscosity of the curing agent mixture may increase due to the oil absorption of the pigment. To 5 parts by weight.

A process for forming a coating layer on a substrate (steel, concrete) surface using the high hardness polyurea coating material using the high hardness polyol according to the present invention will be described as follows.

First, in order to remove the contaminants and existing rust on the steel surface when the high-hardness polyurea is coated on the steel surface, the blasting pretreatment is carried out. After coating the primer to enhance the interlayer adhesion between the substrate and the polyurea coating surface, Urea is coated. In the case of concrete, the concrete is hardened by the hydration reaction, and the water is raised on the surface, resulting in the formation of a laitance layer. This is a very thin layer and shows poor adhesion. Therefore, after removing the laitance layer completely in the pretreatment process and removing the pinhole layer by putty after the pinhole layer is removed, it is necessary to increase the interlaminar adhesion with the polyurea Coat concrete primer only.

When the above process is completed, the polyurea coating is applied at a pressure of 1,800 to 2,300 psi and a temperature of 65 to 70 ° C using a special two-pack type high-temperature, high-pressure mixed collision type polyurea exclusive equipment. Also, in winter, the viscosity of the base and curing agents increases due to the decrease in temperature. In this state, the ideal mixture ratio (volume ratio 1: 1) is not suitable and it is difficult to realize the physical properties of the coating film.

Therefore, during the winter, the heating band is wrapped around the product to increase the temperature indirectly, thereby lowering the viscosity of the product, so that the best coating property can be obtained by the ideal mixing collision.

An embodiment of the present invention will be described in detail with reference to the above description.

As shown in Table 1 below, in Examples 1 to 5, 55 parts by weight of polyetheramine having a molecular weight of 2,000, composition of a curing agent solution, 7 parts by weight of polyetheramine having a molecular weight of 5,000, 13 parts by weight of polydiethyltoluene diamine, 16% by weight of a hard polyether polyol, 1.5 parts by weight of an adhesion promoter, 0.7 parts by weight of a defoaming agent and 4 parts by weight of a colored pigment were immobilized, and the content of NCO groups in the isocyanate, which is a main prepolymerized resin solution, 19% and 20%, respectively.

Example 1 Example 2 Example 3 Example 4 Example 5
subject
Isocyanate weight 100 100 100 100 100
NCO% (16-20%) 16% 17% 18% 19% 20% Hardener Polyether amine (molecular weight: 2,000) 55 55 55 55 55 Polyetheramine (molecular weight: 5,000) 7 7 7 7 7 Polydiethyltoluenediamine 13 13 13 13 13 Polyether polyol 16 16 16 16 16 Adhesion promoter 1.5 1.5 1.5 1.5 1.5 Defoamer 0.7 0.7 0.7 0.7 0.7 Colored pigment 4 4 4 4 4

As shown in Table 2 below, in Examples 6 to 10, the NCO group content of the prepolymer solution as the base solution was fixed at 19%, 55 parts by weight of polyetheramine having a molecular weight of 2,000 as a curing agent composition, 7 parts by weight of polyetheramine having a molecular weight of 5,000 13 parts by weight of polydiethyltoluene diamine, 1.5 parts by weight of an adhesion promoter, 0.7 part by weight of a defoaming agent and 4 parts by weight of a colored pigment, and the polyether polyol was changed to 12, 14, 16, 18 and 20 parts by weight, respectively.

Example 6 Example 7 Example 8 Example 9 Example 10
subject
Isocyanate weight 100 100 100 100 100
NCO% 19% 19% 19% 19% 19%
Hardener Polyether amine (molecular weight: 2,000) 55 55 55 55 55
Polyetheramine (molecular weight: 5,000) 7 7 7 7 7
Polydiethyltoluenediamine 13 13 13 13 13
Polyether polyol 12 14 16 18 20
Adhesion promoter 1.5 1.5 1.5 1.5 1.5
Defoamer 0.7 0.7 0.7 0.7 0.7
Colored pigment 4 4 4 4 4

The high hardness polyurea coating material prepared using the high hardness polyol prepared according to Examples 1 to 10 was prepared and coated on an iron plate to have a thickness of 400 to 500 탆 in order to examine the rustproofing property of the steel surface to obtain rust- Was confirmed by brine spray test for 1,000 hours.

The properties (tensile, elongation, and hardness) of the coating film were determined by a universal material testing machine and a Shore D hardness meter using the high hardness polyol coating prepared using the high hardness polyol prepared in Examples 1 to 10, Lt; / RTI >

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Salt spray
Test (rust prevention) Bad Bad Good Good Good Bad Bad Bad Good Bad The tensile strength
(Mpa) 15 16 18 19 20 14 16 18 20 21 Elongation rate 412 381 359 324 302 387 355 367 325 307 Hardness (Shore D) 47 53 59 66 69 49 54 61 66 crack
Occur

As shown in the above Examples 1 to 5, when a salt water spray test was conducted for 1,000 hours in order to examine the rust resistance of the high-hardness polyurea, it was found that when the NCO content of the subject solution, isocyanate, was 18% It looked.

This shows that when the NCO group content is 19% or more, the crosslinking density (rigidity) in the predetermined coating film is excellent, which prevents the penetration of the salt water to prevent the start of the rusting to the steel substrate. In Examples 6 to 10 Hardness, tensile strength and elongation were excellent when the polyether polyol was 18 parts by weight or more in order to obtain hardness of polyurea coating film of hardness Shore 65 D or higher which is the AWWA C-222 standard.

In the case of Example 10 in which a high hardness polyurethane coating film was obtained, hardness was the best, but fine cracks occurred after a lapse of time (a change with the passage of time), which was problematic in terms of rustproofing property. In the case of the NCO group of the prepolymerized isocyanate The result of Example 9 in which the content was 19% and the polyether polyol as one of the compositions of the curing agent was 18 parts by weight showed the best results in terms of rust resistance, tensile strength, elongation and hardness.

In order to obtain the hardness of the coating (based on AWWA C-222) of the polyurea coating material in order to obtain a physical property of Shore 65 D or more, in the case of the conventional polyurea coating material, the NCO content of the isocyanate was increased, A coating film is formed within a few seconds, and due to the shrinkage due to the heat of reaction, many problems are caused in adhesion to the surface.

However, the addition of polyetheramine and a polyether polyol having a high hardness to isocyanate increases adhesion strength and hardness property compared with conventional polyurea coating agents, and also has properties of complementing elongation and elongation of curing time It is possible to make a high hardness polyurea coating material free from coating cracks even at a low temperature.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And the scope of the present invention should be understood as the following claims and their equivalents.

Claims (5)

100 parts by weight of isocyanate having an NCO group content of 18 to 20%; And
50 to 60 parts by weight of a polyetheramine having a number average molecular weight of 2000, 5 to 10 parts by weight of a polyetheramine having a number average molecular weight of 5,000, 10 to 15 parts by weight of polydiethyltoluenediamine, 18 parts by weight of a polyether polyol having a weight-average molecular weight of 500, 1 to 2 parts by weight of an adhesion promoter, 0.5 to 1 part by weight of a defoaming agent, and 3 to 5 parts by weight of a colored pigment; / RTI >
Characterized in that the topical and curing agents are mixed in a volume ratio of 1: 1
High hardness polyurea coating composition.
delete delete delete The method according to claim 1,
The adhesion promoter may be selected from the group consisting of gamma-methacryloxypropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and beta- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane (? - (3,4-epoxycyclohexyl) ethyltrimethoysilane).
High hardness polyurea coating composition.