KR101280533B1 - Polyurea coating method - Google Patents

Abstract

PURPOSE: A method for coating polyurea without removing moisture from a wet surface is provided to obtain strong durability and to increase surface smoothness by extending a gel time and a tack free time. CONSTITUTION: A method for coating a mixture mixing an A-agent and a B-agent to a wet surface is provided. The A-agent is hexamethylene di-isocyanate (HDI) having 18-20 vol.% of isocyanate (NCO). The B-agent is composed of 36-50 vol.% of polyetheramin, 31-45 vol.% of chain extender and curing agent, 1-15 vol.% of crosslink, and 0.1-4 vol.% of additive. The A-agent and the B-agent are mixed and sprayed at 1,500-2,000 psi after being preheated at 65±5°C. At this time, the A-agent and the B-agent can be sprayed to the wet surface without removing moisture from the wet surface.

Description

Polyurea coating method that can be coated without removing moisture on wet surface {POLYUREA COATING METHOD}

The present invention relates to a polyurea coating method, and more particularly, to a polyurea coating method capable of having a high durability and high wear resistance as a main component of a reactive component insensitive to moisture.

As the pipes of water supply and sewage are buried, scales are created in the inner diameter of the pipes as the years of burying are in place. Many problems arise.

In order to solve these problems, the rehabilitation method of the old water and sewage pipes is performed at regular intervals. The water and sewage pipe rehabilitation method may be, for example, a customs method and a lining method.

The customs method refers to the method of removing the scale generated in the inner diameter of the upper and sewage pipes using high pressure water or scraper, and the lining method is about 80 ~ 150 ℃ for the descaled water and sewage pipes through the customs method. After drying by using high temperature air to completely remove the water in the pipe, it is a method of forming a coating layer of a predetermined thickness by spraying the coating liquid on the inner diameter of the upper and the sewer pipe.

On the other hand, as a material of the coating layer used in the lining method, in the past, ceramic mortar was mainly used, but recently, polyurea made of isocyanate has been used a lot.

Polyurea has very high mechanical strength, elasticity, acid resistance, alkali resistance, chemical resistance, etc., and it can be installed within a short period of time due to its fast curing speed. It is widely used as waterproofing / reinforcing materials for structures exposed to water.

However, even when the polyurea having such good physical properties is wet, there is a problem that swelling (pocket) occurs during construction and the durability is inferior, and various methods for solving this problem are being sought.

Related technologies include Republic of Korea Patent No. 0858131 (August 14, 2007, Announcement, Name: Polyurea lining device for water and sewage aging pipe) Polyurethane-polyurea paint, a method for preparing the same, and a method for forming an inner coating film of a water pipe.

The present invention has been made to solve the above problems, it is possible to exhibit a strong durability without the swelling, dropping, etc. due to moisture, polyurea coating to increase the surface smoothness by extending the gel time and Tekpritime To provide a way.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above.

The present invention to solve the above problems,

In the method of isocyanate prepolymer A agent and the curing agent B agent in a polyurea coating equipment in a volume ratio of 1: 1, each spray coating on the wet surface,

A agent is prepared by preparing the isocyanate group (NCO) content of 18 to 20% by volume of HDI (Hexamethylene Di-isocyanate) in aliphatic isocyanate, and preheating agent A and agent B at 65 ± 5 ° C. The present invention provides a polyurea coating method characterized by spraying by mixing at pressure, but spraying without removing moisture on the wet side.

Specifically, agent B is 36-50% by volume of polyetheramine, 31-45% by chain extender & curing agent, 1-15% by crosslinker and It may be added at 0.1-45% by volume of an additive.

And the coating composition sprayed from the equipment has a gel time of 30 to 60 seconds, it is preferable that the free time is 2-3 minutes.

In addition, the polyurea coating may be applied to the wet side of water, sewage rehabilitation pipe, concrete, steel, wood.

1 is a picture taken the appearance of swelling after the construction of a general polyurea,
Figure 2 is a comparison picture taken a state in which the general polyurea construction and the present invention polyurea construction on a moisture specimen,
3 is a photograph of the results of the adhesion test after the construction of the polyurea according to the present invention, and
Figure 4 is a photograph taken a state of construction on the concrete and steel surface with a polyurea according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like elements in the figures are denoted by the same reference numerals wherever possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In general, polyurethane, polyurea, and epoxy using a reactive isocyanate prepolymer have a characteristic of reacting depending on the air content or the water content of the material or the function of the coating matrix. As shown in FIG. 1, the process of removing moisture is generated as the biggest problem in the coating process as the bumps (pockets) are generated when the polyurea coating is applied on the moisture surface.

In addition, in the case of underground structures that are difficult to remove moisture, it is difficult to virtually perfect waterproof and protective coating due to the continuous generation of moisture.

Currently, in Korea and abroad, various coating methods for rehabilitation of water and sewage pipes have been proposed, and the most difficult problem in rehabilitation pipe coating is the process of water removal. Due to this moisture, there is a problem of swelling of the construction part, a problem of 1: 1 quantitative mixing of agent A and agent B, and a problem in that the coating composition does not derive the value of the designed physical property by reacting with moisture. Appearing.

In addition, the dew condensation and water is generated due to the drop in adhesion between the primer surface and the coating surface occurs.

In order to solve this problem, the moisture surface should be dried in a state that can be coated, but it may not be possible in the case of a structure in which the construction section is underground or continuously generating moisture.

Therefore, the present invention is to find a method using a mechanism that does not react with water or a small reaction to develop a polyurea coating that exhibits a form that does not react with water even when a certain amount of water is present, and adhesion performance even when a certain amount of water is present.

Accordingly, through various experiments on isocyanate prepolymers that have a direct influence on the reaction with water among the polyurea components, the focus is on the preparation of the isocyanate prepolymer having the lowest sensitivity to water, and also due to the characteristics of the polyurea, The focus was on minimizing the incidence of defects on the construction of the air shortening and the wet surface by applying the coating technology intact. Focusing on polyurea manufacturing technology that satisfies the dissolution test so that it can be coated on drinking water facilities by eliminating the additional use of materials to increase the adhesion to the surface by increasing the initial gel time and the tape pre-time, thereby increasing the adhesion to the surface. Placed.

Example 1

1) Agent A: The reactor isocyanate group (NCO) content was adjusted to 20% by volume using a general polyurea prepolymer (MDI) widely used in Korea.

2) Agent B: As a curing agent, polyetheramine, a crosslinking agent, a chain extender, a curing agent, and an additive were used.

3) The submerged specimen was taken out and sprayed to mix A and B in a volume ratio of 1: 1 without removing water (wet surface state).

The blending ratio for the above agent B is 30-50% by volume of polyetheramine, 1-15% by volume of CrossLink, 20-% of Chain Extender & Curing Agent. 45 vol% and addictive is 0.1-4 vol%.

The main agent, A, determines the soft, semi-hard, medium-hard, and hard type due to the isocyanate group (NCO) control and adjusts to the application.

Hardening agent B agent is adjusted by mixing according to the characteristics of each raw material by simple mixing. As a property of the curing agent, it plays a role of controlling physical properties such as tensile strength and elongation and curing time.

Polyetheramine (Polyetheramine) affects physical properties such as elongation and tensile strength, and gives a characteristic that the physical properties decrease or become high depending on the amount of addition. If physical properties are higher than the reference value, problems may arise in terms of use.

Cross link material acts as a crosslinking material. Such cross-linking agent (Cross Link) generally refers to a multifunctional group of three or more functional groups, and serves as a network structure to tightly bind tissues when a main chemical and a curing agent meet and cause a chemical reaction. At this point, Cross Link does not put too much, because if you add too much, you may lose its functionality.

Chain Extender & Curing Agent plays a pivotal role in pot life and curing time, and can be controlled according to the purpose and are generally used as a chain extender. To give the physical properties of the chain.

Additive is used as an additive to add additional functions such as increased adhesion, sun protection, antifoaming, hygroscopic, flame retardant, and does not add a large amount.

In one embodiment of the present invention, the formulation of the above agent B is 1% by volume crosslinker (CrossLink), 50% by volume polyetheramine, 45% by chain extender (Cain Extender) & curing agent (Curing Agent) %, And additives (addictive) was added in 4% by volume was used in 1: 1 with the agent A.

After the spray as described above, by measuring the state and adhesion of the coating surface it was possible to obtain the following results.

코팅) Coated surface condition: There were many small pockets of protrusion shape due to moisture.

Ii) Adhesion measurement: Adhesion of concrete surface was 1Mpa, less than 3.5Mpa of dried specimen.

겔) The gel time was 25 seconds, and the tex-free time was 1 minute and 40 seconds, which was close to the target value, but the reaction to moisture did not yield satisfactory results.

[Example 2]

1) Agent A: A prepolymer was prepared by using an isocyanate having the same isocyanate group (NCO)% as in Example 1 and having a high content of 2,4′-, 2,2′-Di PIenyl methane diisocyanate.

2) Agent B: The same curing agent as in Example 1 was used.

3) The agent A: agent B to the volume ratio of 1: 1 to the experiments in the same conditions as in the first embodiment was obtained the following results.

코팅) Coated surface condition: There were many small pockets of protrusion shape due to moisture.

Ii) Adhesion measurement: Adhesion of concrete surface was 1Mpa, less than 3.5Mpa of dried specimen. In the case of the iron surface, a value smaller than 12 Mpa of the iron plate dried at 4 Mpa was derived, and the result showed that the adhesion decrease due to moisture occurred.

겔) The gel time was 35 seconds and the tex-free time was 1 minute and 40 seconds, which resulted in close to the target value, but it did not produce satisfactory results due to the reaction to moisture.

[Example 3]

Due to the long development experience that aliphatic isocyanate is used more frequently as brush type or roller coating because the reaction rate is slower than aromatic isocyanate,

1) Agent A: IPDI (Isophorn Di-isocyanate), a typical aliphatic isocyanate, was reacted at 20% by volume of isocyanate group (NCO) for prepolymerization.

2) Agent B: The same curing agent as in Example 1 was used.

3) The agent A: agent B to the volume ratio of 1: 1, the experiment was carried out under the same conditions as in the first embodiment, the following results were obtained.

코팅) Coated surface condition: The number of small pockets of protrusions caused by moisture decreased but still occurred.

Ii) Adhesion measurement: The adhesion of concrete surface was 1.5Mpa, which was smaller than the dried specimen 3.5Mpa. In the case of the iron surface, a value of less than 12 Mpa of the iron plate dried at 6.3 Mpa was derived to show that the adhesion decrease due to moisture occurred.

겔) Gel time was 55 seconds and Tekpreh time was 2 minutes and 40 seconds, and the result was close to the target value, but the reaction to moisture did not yield satisfactory results.

Example 4

1) Agent A: HDI (Hexamethylene Di-isocyanate) in aliphatic isocyanate was used as the same amount of isocyanate group (NCO) as in Example 1.

2) Agent B: The same curing agent as in Example 1 was used.

3) The agent A: agent B to the volume ratio of 1: 1 to the experiments in the same conditions as in the first embodiment was obtained the following results.

Iii) Coating surface condition: It was possible to obtain a good coating surface without any small pockets of protrusions caused by moisture.

It can be seen that a stable polyurea coating film was formed to prevent the phenomenon of reacting with moisture such as a pocket even when coated on the water surface.

Ii) Adhesion measurement: The adhesion of the concrete surface was 3.5Mpa, which could be the same or higher than that of the dried specimen 3.5Mpa. The convex surface also shows almost the same value as the iron plate 12Mpa dried to 11Mpa, showing a much higher adhesion than the polyurea of the previous embodiment.

It is believed that this is an isocyanate amine reaction which is hardly reacted with moisture on the surface and is unique to polyurea.

Viii) The gel time was 45 seconds and the Tekpre time was 2 minutes and 05 seconds.

In the above examples, the reactor of the polyurea prepolymer was adjusted to 20% by volume of isocyanate group (NCO), but it can be seen from the experimental results that it may be expanded to 18 to 21% by volume. In other words, when the isocyanate group (NCO) content is less than 18% by volume, hardness and durability are lowered, whereas when the isocyanate group (NCO) content is less than 21% by volume, the hardness is so high that it is vulnerable to impact and can be used within this range.

The targets of gel time and techfree time are 30 to 60 seconds and 2 to 3 minutes, and the optimum coating surface can be obtained only within this target value. That is, when the foreign matter or the 1: 1 discharging cannot be splashed due to the influence of gel time or tex free time, the main body or hardener will splatter in the gel time. Therefore, there is an advantage of reducing the occurrence of trouble. In addition, the longer the gel time, the longer the time to penetrate to the surface has a great effect on improving the adhesion.

As described above, the polyurea coating composition according to the present invention is used by mixing agent A and agent B, which is used in a polyurea coating equipment. That is, the polyurea coating equipment has a separate container containing the agent A and the agent B to preheat each material to 65 ± 5 ° C., and then spray the gun at a pressure of 1,500 to 2,000 psi.

In the polyurea coating composition according to the fourth embodiment of the present invention, as shown in FIG. 2, it can be seen that a smooth surface appears when the general polyurea coating composition is applied to the wet side specimen.

In addition, the polyurea coating composition according to the fourth embodiment of the present invention, as shown in Figure 3, it can be seen that up to 1,750psi in the adhesion test test after the polyurea coating construction.

And the polyurea coating composition according to the fourth embodiment of the present invention as shown in Figure 4 as a result of the construction on the concrete surface and steel surface it was found that neither the projection nor the pocket phenomenon.

In addition, the polyurea coating composition according to the fourth embodiment of the present invention is applicable to the water, sewage rehabilitation pipe, as well as concrete, steel, wood as the application range.

The present invention is not limited to the configuration and operation of the embodiments described above. The embodiments may be configured so that all or some of the embodiments may be selectively combined so that various modifications may be made.

Claims (4)

In the method of isocyanate prepolymer A agent and the curing agent B agent in a polyurea coating equipment in a volume ratio of 1: 1, each spray coating on the wet surface,
The agent A is prepared by preparing an isocyanate group (NCO) of 18-20% by volume of HDI (Hexamethylene Di-isocyanate) in aliphatic isocyanate,
The B agent is 36-50% by volume of polyetheramin, 31-45% by volume of chain extender & curing agent, 1-15% by crosslinking agent, additives (addictive) 0.1-4% by volume,
After preheating the agent A and agent B to 65 ± 5 ℃, and sprayed by mixing at a pressure of 1,500 ~ 2,000psi, spraying without removing the moisture of the wet surface polyurea coating method.
delete The method of claim 1,
The coating composition sprayed from the equipment has a gel time 30 ~ 60 seconds, the polyprea coating method, characterized in that 2 to 3 minutes.
The method of claim 3, wherein
The polyurea coating is a polyurea coating method characterized in that applied to the wet surface of the water, sewer rehabilitation pipe, concrete, steel, wood.

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