KR101643520B1

KR101643520B1 - Waterproof Coating Method of Structure

Info

Publication number: KR101643520B1
Application number: KR1020160000822A
Authority: KR
Inventors: 김대중
Original assignee: 주식회사 제이투이앤씨
Priority date: 2015-03-31
Filing date: 2016-01-05
Publication date: 2016-07-27

Abstract

According to the present invention, when a roof layer is formed on a roof of a building made of a material such as concrete or brick or waterproof coating of a water tank, etc., and the super micro fiber is mixed with either a urethane resin or a polyurea resin, Since the waterproof layer is formed, pinholes on the surface of the undercoat layer are prevented from being formed, and further processing for forming or attaching a reinforcing member or a vertical member for performing waterproof function is unnecessary, which can greatly reduce the manual work required for waterproofing, There is an advantage of shortening the time.

Description

Waterproof Coating Method of Structure Using Super Micro Fiber Scaffold

The present invention relates to a polyurea waterproof coating method using a super micro fiber based regulating material, and more particularly, to a method for producing a polyurea waterproof coating method using a super micro fiber as a base material for a waterproof coating of a structure, To a polyurea waterproof coating method using a super micro fiber based regulating material.

Generally, in case of concrete building structure, when water such as rainwater penetrates due to fine pinholes or cracks, a part of the water does not evaporate and penetrates into the building and adversely affects the durability of the structure. Therefore, And waterproofing works on structures such as floors. In particular, the underground water tank requires a great deal of processing time because it requires a complete shutoff of water leakage in the water tank.

Materials such as asphalt and coal tar pitch are mainly used as waterproofing materials for conventional buildings. They are formed by applying or spraying asphalt or coal tar pitch directly on the surface of a building to form a waterproof layer, or paper impregnated with asphalt or coal tar, It is also covered with mortar, concrete, etc. to protect the construction surface. Of course, such a method of directly applying or spraying such asphalt or coal tar pitch on the surface of a building is advantageous in construction and inexpensiveness. However, when cracks occur in the structure, the waterproof layer is destroyed and waterproof effect can not be attained. Asphalt or coal tar It is difficult to find and repair the defective part when the water is leaked.

In order to solve these problems, many waterproofing methods have recently been proposed for the construction of roofs, walls, and floors of buildings using highly rigid urethane, urethane waterproofing agent, and polyurea resin as a base adjusting material. However, as described in Japanese Patent Application Laid-Open No. 10-2007-0087418, when a high hardness urethane or urethane waterproofing agent is used after primer application, there is still a pinhole due to the suction property of concrete. Therefore, the hardened urethane or urethane waterproofing agent coating And it is still difficult to remove the pin hole.

In order to overcome the problem of pinholes in order to solve this problem, there is a problem that the waterproofness of the concrete is not good due to the poor watertightness of the polyurea resin applied to the concrete structure, It is inevitable to apply the nonwoven fabric, the asphalt sheet and the urethane resin before the construction. For example, EP 10-0408010 discloses a waterproofing method using polyurea. The nonwoven fabric used as a reinforcing member is fixed on a waterproof base using a nail or a washer before spray coating the polyurea, and then the polyurea is applied. As another example, Korean Patent No. 10-0956489 relates to a polyurea waterproof coating method for a concrete structure, which comprises a first to a fourth step of forming a primer layer, a coating layer, Lt; / RTI > Therefore, in order to solve the problem that the waterproof function can not be faithfully performed, it is necessary to further attach the reinforcing member or the vertical member before the polyurea resin is applied or sprayed. Therefore, There is also a problem of lengthening.

Reference 1: Published Patent No. 10-2007-0087418 Reference 2: Registration No. 10-0408010 Reference 3: Registration No. 10-0956489

Therefore, the present invention is based on a urethane waterproofing agent, a high hardness urethane or an epoxy resin, and a pinhole is not formed when applying or spraying, so that a step of applying or forming a separate reinforcing member or a vertical member is required The object of the present invention is to provide a polyurea waterproof coating method using a super micro fiber based regulating material which can easily perform waterproofing or finishing of a building.

The present invention also provides a polyurea waterproof coating method using a super micro fiber-based regulating material capable of quickly performing a waterproofing treatment using a urethane waterproofing agent, a high-hardness urethane or an epoxy resin, The purpose is to provide.

In order to solve such a technical problem,

A first step of forming a primer layer by applying a primer to the surface of the structure; A second step of forming a primary intermediate layer by applying a base adjusting material obtained by mixing any one of urethane waterproofing agent, high hardness urethane and epoxy resin with super micro fibers at a certain ratio; A third step of forming a secondary intermediate layer by applying any one of the high hardness urethane, urethane waterproofing agent and polyurea resin to the surface of the primary intermediate layer; And a third step of applying a urethane waterproofing agent or a polyurea resin to the surface of the secondary intermediate layer to form a top layer.

At this time, before the first step, the surface of the structure is subjected to any one of BLASTING, CHIPPING, DIAMOND WHEEL GRINDING, and 10% HCL acid cleaning to remove contaminants. Further comprising the steps of:

The background adjusting material in the second step is characterized in that any one of a urethane waterproofing agent, a high hardness urethane and an epoxy resin and super micro fibers are mixed at a weight ratio of 1000: 1 to 1000: 2.

According to the present invention, it is possible to provide a waterproof coating for roofs, water tanks, etc. of a building made of concrete or brick, Since the waterproof layer is formed with the desk adjuster, pinholes on the surface of the undercoat layer are prevented from being formed, and further processing for forming or adhering a reinforcing member or a vertical member for performing a waterproof function is unnecessary, There is an advantage of saving and reducing construction time.

Particularly, since the existing desk adjustment material applied on the vertical wall surface of the structure has a high viscosity, when the trowel is troweled, a trowel is formed on the surface and pin holes are pushed by an artificial force. Therefore, after the operation, internal air pockets are formed, It is necessary to apply it again several times. Especially in case of a low-viscosity base adjusting material, since it is often permeable to water such as osmotic pressure after application, a constant coating film and pinholes are generated on the surface and it must be applied several times. In addition, In the present invention, the adjustment material mixed with the super micro fibers is used to allow the fiber to permeate the concrete (after the surface treatment) itself, and to improve the tensile strength of the tread according to the characteristics of the background adjusting material Improved waterproof quality by catching constant film and pinholes on the surface It may be, there is an effect that can reduce labor costs and waste, improved working processes.

1 is a process diagram of a waterproof coating of a building structure according to the present invention.
2 is a waterproof construction sectional view of an architectural structure according to the present invention.
3 is a graph comparing the tensile strengths (N / mm 2) of the base adjusting material and the urethane waterproofing material using the super micro fibers according to the present invention.
4 is a graph comparing elongation percentages (%) of a conventional urethane waterproofing material using a super micro fiber according to the present invention.

The features of the waterproof coating method of the building according to the present invention will be understood by referring to the accompanying drawings. 1 is a view illustrating a waterproof coating process of a structure according to the present invention, and FIG. 2 is a waterproof construction sectional view of a structure according to the present invention.

1 and 2, the waterproof coating method of a structure according to the present invention comprises a base treatment step (S100) for removing contaminants on the surface of a building structure made of concrete bricks and the like, a step of applying a primer (S110) for forming a primary intermediate layer, a primary intermediate layer forming step (S110) for forming a primary intermediate layer by applying a base adjusting agent obtained by mixing any one of urethane resin and epoxy resin with a super micro fiber (S130) forming a secondary intermediate layer by applying any one of a urethane resin and a polyurea resin to the surface of the primary intermediate layer (S130); applying a urethane waterproofing agent or poly And an upper layer forming step (S140) for forming a top layer by applying a urea resin.

At this time, the super micro fiber is used as a curing crack controlling reinforcement used for concrete mortar and reinforcing steel construction reinforcing steel. This is because it has a large quantity per unit, maximizes the effect, controls curing crack, drying shrinkage and temperature crack, Specific gravity is heavier than water and does not float on the surface. Supermicro fiber has excellent chemical resistance and durability, high abrasion resistance, impact resistance and anti-seismic resistance.

Especially, super micro fiber has excellent ability to control curing cracks and shrinkage cracks, increase wear resistance, and has high chemical resistance and durability. It is excellent in crack prevention and floor stopper such as slope and vertical surface due to increase in adhesiveness, When used as a floor finishing material, it has excellent cracking, phenol, tensile strength and expansion / contraction ratio due to increased bonding strength.

The polyurea resin is a reaction product of an isocyanate and a polyetheramine having a primary amine at a terminal, and can be made into an elastic coating (spray elastic body) by a commercial high pressure, high temperature impact mixing spray machine. It uses polyetheramine as a raw material and is 100% solids with no volatile matter.

This polyurea resin is a non-catalyzed fast cure type, and when used for waterproof treatment, it has a gel time within 3 ~ 5 seconds after spraying, so it can be sprayed without slipping on slope and vertical surface. Seconds. It is hardly affected by water and temperature during construction, and is less affected by climate change, moisture, heat, and cold.

And the polyurea resin has excellent adhesion to various adherends. By using the quick reactivity of these resins, it is possible to produce an elastic body having excellent adhesion. Factors influencing the adhesion of polyurea resins include the surface conditions of the substrate (treatment), the prescription technology of the resin and its reactivity, and these factors should be consulted when constructing.

Such a polyurea resin can be applied after finishing in the case of an iron parking lot, but when it is used for waterproofing in parking lots, warehouses, warehouses and rooftops, it is necessary to use a high- It can be used to finish with polyurea after work.

On the other hand, the background adjusting material is formed by mixing any one of urethane resin and epoxy resin with super micro fibers at a certain ratio, and when coating the surface, it is applied to a substrate using a roller or a spray gun to coat the substrate to an arbitrary thickness.

At this time, when either one of the urethane resin and the epoxy resin and the super micro fiber are selectively mixed, the mixing ratio of any one of the urethane resin and the epoxy resin and the super micro fiber is mixed in a weight ratio of 1000: 1 to 1000: 2 When waterproofing treatment is carried out using the above-mentioned base adjusting agent, the hardening agent and / or the accelerator may be mixed and used in an optional ratio as required.

More specifically, the background adjusting material may be 0.02KG of super micro fiber mixed with urethane resin and epoxy resin 20KG at the time of mixing, for example, in the case of the floor adjusting material for floor, For example, supermicro fibers may be mixed with 0.04 Kg of the urethane resin and the epoxy resin 20 KG at the time of mixing. Of course, such a ratio can be adjusted at various ratios depending on the application or the surrounding environment.

The urethane resin can be classified into high hardness urethane and urethane waterproofing agent depending on hardness difference. For example, high hardness urethane can be used for the wall, and urethane waterproofing agent is mainly used for waterproofing. There is a slight difference.

Such a urethane resin can be prepared by varying the composition ratio of the composition. In one embodiment of the urethane resin, the urethane resin includes a urethane prepolymer having a free NCO content of 3 to 7 wt% and a polyol curing agent, From 40 to 60% by weight of a filler, from 0.1 to 10% by weight of a pigment, from 20 to 40% by weight of a polyol and from 0.01 to 5% by weight of a catalyst.

Wherein the urethane prepolymer and the polyol curing agent are composed of a urethane prepolymer to a polyol curing agent in a weight ratio of 1: 1 to 3, and the polyol curing agent is a bismuth compound to a zinc compound in a weight ratio of 1: 1 to 50.

The urethane prepolymer has a free NCO content of 3 to 7% by weight. The polyol having a number average molecular weight of 2000 to 3000 and a triol having a number average molecular weight of 3000 to 4000 is mixed with a polyol Isocyanate is added at an equivalent ratio of 1: 1.0 to 2, and the reaction is carried out at 80 ° C until free NCO (%) = 5.0 ± 2%. If necessary, 1,3-butylene glycol 3-Butylene Glycol), trimethylolpropane (Tri methylol Propane), and the like.

The inorganic filler contained in the polyol curing agent functions as a filler and is preferably contained in an amount of 40 to 60 wt% in the polyol curing agent. When the content of the inorganic filler is within the above range, the mechanical strength is improved and the cost is reduced. Examples of the inorganic filler include, but are not limited to, calcium carbonate (CaCO3), barium sulfate (BaSO4), silicon dioxide (SiO2), calcium oxide (CaO), and talc.

The pigment preferably serves as a coloring agent and is contained in an amount of 0.1 to 10% by weight in the polyol curing agent. The pigments include Ti, Cyanine, Carbon, Fe, and ceramics. When the content of the pigment is within the above range, the pigment is effective to realize a specific color.

The polyol is a polyol mixed with triol having a number average molecular weight of 3,000 to 4,000 and diol having a number average molecular weight of 2,000 to 3,000, . The polyol is preferably contained in an amount of 20 to 40% by weight in the polyol curing agent. When the content of the polyol is within the above range, there is an effect of improving the cost, improving the mechanical strength and expansion ratio.

The bismuth compound is preferably contained in an amount of 0.01 to 5% by weight in the polyol curing agent. When the content of the polyol is within the above range, securing of workability, increase of expansion and contraction ratio and increase of mechanical strength are effected by controlling the reaction rate.

It is preferable that the zinc compound is contained in the polyol curing agent in an amount of 0.01 to 5 wt%. When the content of the zinc compound is within the above range, there is an effect of increasing the mechanical strength and accelerating the tacky property by accelerating the crosslinking reaction.

In another embodiment of the urethane resin, 10 to 30% by weight of PPG (PolyPropylene Glycol), 5 to 20% by weight of TDI (Toluene Diisocyanate) or MDI (Methane Diisocyanate), 30 to 50% by weight of calcium carbonate, 5% by weight of a polyurethane composition. At this time, 10 to 30% by weight of PPG (PolyPropylene Glycol) and 5 to 20% by weight of TDI or MDI are mainly used. 30 to 50% by weight of the calcium carbonate and 0.01 to 5% by weight of the catalyst are curing agents.

At this time, PPG (Polypropylene Glycol) accounts for 10-30 wt% of the total weight of the urethane resin. When PPG (PolyPropylene Glycol) is mixed at less than 10 wt%, cracking of the cured product may occur, The strength can be lowered. If PPG (PolyPropylene Glycol) is more than 30% by weight of the total urethane resin, the production cost of the urethane resin may be greatly increased and the hardness of the coating film may be lowered.

When TDI (Toluene Diisocyanate) or MDI (Methane Diisocyanate) is mixed in an amount of less than 5% by weight, the TDI (Toluene Diisocyanate) or MDI (Methane Diisocyanate) accounts for 5 to 20% by weight of the total weight of the urethane resin. The base and the curing agent are not dried, and if it exceeds 20% by weight, the manufacturing cost of the urethane resin is greatly increased.

In addition, calcium carbonate accounts for 30 to 50% by weight of the total weight of the urethane resin. If less than 30% by weight of calcium carbonate is added, a large amount of PPG is added, thus increasing the manufacturing cost of the urethane resin. , The mechanical properties and strength are deteriorated and a cracking phenomenon occurs.

On the other hand, the epoxy resin is excellent in heat resistance, electrical insulation and adhesiveness, and can be used in combination with a curing agent, a filler, and a reinforcing agent. In order to be suitable for waterproofing, bisphenol- From 10 to 25% by weight of a rubber-modified epoxy resin and from 30 to 80% by weight of a modified epoxy resin by at least one of rubber, dimer acid and monomeric urethane, and carboxyl-terminated liquid butadiene-acrylonitrile rubber (CTBN) Topic; A curing agent comprising 67 to 100% by weight of a modified aliphatic amine, 0 to 3% by weight of a curing accelerator, and 0 to 30% by weight of a filler.

At this time, 100 parts by weight of the subject is composed of 10 to 40 parts by weight of a curing agent. The subject matter further includes at least one selected from the group consisting of 1 to 2% by weight of a pigment, 1 to 2% by weight of a thixotropic agent, 0.1 to 1% by weight of an ultraviolet stabilizer, and 1 to 2% by weight of an antibacterial agent.

If the bisphenol-type epoxy resin is contained in an amount of less than 10% by weight, the physical properties and mechanical strength of the bisphenol-type epoxy resin are lowered. If the amount of the epoxy resin is more than 30% by weight, There is a problem that is raised.

If the filler is contained in an amount of less than 30% by weight, the amount of the bisphenol-type epoxy resin is increased to increase the cost. On the other hand, if the filler content exceeds 70% by weight, A phenomenon occurs and the mechanical strength is lowered.

Hereinafter, the polyurea waterproof coating method using the super micro fiber based regulating material according to the present invention will be described in detail.

(S100) Background processing step

First, the concrete is laid and bred to completely remove contaminants such as LAITANCE, dust, oil, etc. of the surface of the underground water tank structure 10 in the completed building.

The priming treatment removes contaminants through BLASTING, CHIPPING, DIAMOND WHEEL GRINDING, or 10% HCL pickling.

At this time, when the undercoating process of the structure 10 is performed, the undercoat layer 20 is formed on the dense ground surface which is difficult to penetrate the undercoat, causing poor adhesion of the waterproof layer 30 to be described later, It is preferable to sufficiently perform surface pretreatment. In this case, a suitable PH value is 7 to 9, and a water content is preferably 6% or less.

Particularly, it is preferable to perform primer coating and sealing after V-cutting, and to apply coating after surface adjustment, especially in areas where crevices, grooves and cracks are severe or expansion joints. In general, urethane is caulked at the edges of the wall and floor.

(S110) Substrate layer forming step

After the surface treatment of the surface of the structure 10 is performed through the above step S100, the primer layer 20 is formed by applying a primer for priming to the surface of the substrate 10 such as the wall and the floor. This is for the pretreatment of the surface of the structure 10, using a urethane primer and being sprayed so as to be sufficiently absorbed on the surface.

In this case, the thickness of the undercoating layer 20 is preferably 50 탆, for example, and it may be formed to have various thicknesses as required. Particularly, it is preferable to uniformly form the undercoating layer 20 so that a coating film is not partially formed.

Further, it is possible to perform additional coating with no dilution on the surface of the substrate where the moisture absorption of the primer is severe, but care should be taken not to form a thick coating layer on the surface, and further coating of primer can be omitted in the case of a good substrate without a poor surface.

If the primer is removed during grinding after forming the undercoat layer 20, it is preferable to remove the moisture so that the water content in the substrate is less than 6%, and then perform painting.

After the undercoat layer 20 is formed on the surface of the structure 10, it is cured at room temperature (15 to 25 ° C) for a predetermined period of time. In this case, it is preferable that the curing temperature of the undercoat layer 20 is natural cured for at least 2 hours at 20 캜.

(S120) Primary intermediate layer forming process

After forming the undercoat layer 20 on the surface of the structure 10 through the above step S110 and removing the contaminants on the surface of the undercoat layer 20, one of the urethane resin and the epoxy resin, To 1000: 2, to form the primary intermediate layer 30.

In this case, the thickness of the primary intermediate layer 30 is preferably 0.5 to 2 mm, for example. Particularly, it is preferable to form the waterproof layer 30 uniformly so that the primary intermediate layer 30 is not partially formed.

In this case, the primary intermediate layer 30 is formed by a roller or a spraying operation by mixing the base adjusting material and the curing agent in a predetermined ratio. At this time, it is preferable that the above-mentioned desk adjuster and the curing agent are mixed in a weight ratio of 1: 1.

Since such a background adjusting material contains super micro fibers, it is possible to suppress the occurrence of pinholes when applied to the surface of the undercoat layer 20, so that no additional process is required to form or adhere the reinforcing member or the vertical member. Thus, the manual work is greatly reduced, Simple. At this time, curing is performed 24 to 48 hours after the primary intermediate layer 30 is formed.

The primary intermediate layer 30 may be a mixture of a urethane waterproofing agent and a super micro fiber in the case of water leakage prevention and a mixture of a high hard urethane and a super micro fiber at the time of wall surface preparation in a water tank or the like .

When the primary intermediate layer 30 is formed, pinholes are not generated by the super micro fibers even when the surface suction force of the structure 10 is applied.

(S130) Secondary intermediate layer forming process

After the contaminants on the surface of the primary intermediate layer 30 formed through the above step (S120) are removed, a secondary intermediate layer 40 is formed by applying urethane resin or polyurea resin.

In this case, the secondary intermediate layer 40 is preferably formed to have a thickness of 0.5 to 2 mm, for example, as in the case of the primary intermediate layer 30, and may be formed to have various thicknesses as required.

At this time, when the urethane resin and the super micro fiber are mixed with each other, the primary intermediate layer 30 is coated with a urethane resin or a polyurea resin to form the secondary intermediate layer 40.

(S140) The upper layer forming step

The secondary intermediate layer 40 is formed on the surface of the primary intermediate layer 30 through the above step S130 and the contaminants on the surface of the secondary intermediate layer 40 are removed and then the urethane resin or the polyurea resin is applied Thereby forming a top coat layer 50.

In this case, the urethane waterproofing agent or the polyurea resin and the curing agent may be mixed at various ratios. For example, it is preferable to mix the curing agent at a ratio of 7: 1 and spray the mixture to form a thickness of 0.5 mm (500 탆).

At this time, when the secondary intermediate layer 40 is formed by applying urethane resin, the upper layer 50 is formed by applying the urethane resin. When the secondary intermediate layer 40 is formed by applying the polyurea resin It is preferable to form the top coat layer 50 by applying a polyurea resin.

As described above, the conventional waterproof coating method requires a waterproof layer to be applied on the basis of an average of 3 mm. However, in the polyurea waterproof coating method of the present invention, the performance of the long intrinsic strength is improved by adding the super micro- The same effect as the existing waterproof coating method can be exhibited. As described above, the polyurea waterproof coating method of the present invention is superior in workability due to the thickness of the waterproof layer being thinner than the existing waterproof coating method, and it is possible to reduce the cost and minimize the occurrence of environmental wastes.

On the other hand, FIG. 2 is a photograph of a state in which a coating composition is coated on the surface of a structure in which a conventional base adjusting agent is applied. When a base adjusting agent containing no super micro fibers is applied, A uniform coating film and pinholes are generated.

On the other hand, FIG. 3 is a photograph of a state in which the surface of the structure is coated with the ground adjusting material using the super micro fibers according to the present invention. The fiber catches the moisture of the concrete (after the surface treatment) itself, .

(Test Example)

The mechanical strength of the ground adjusting material obtained by mixing supermicro fibers at a weight ratio of 1000: 1 to 100: 2 with one of the main materials of the present invention, urethane (high hard urethane), was compared with a normal exposed urethane waterproof material and hard urethane Are shown in Table 1 below.

Properties KS F 3211 (2008) urethane rubber system
Class 1 Standard Specification Hard polyurethane flooring Super Micro Fiber + Rigid Polyurethane Flooring (Invention) Tensile strength (N / mm 2) 2.5 ↑ 5.61 7.14 Elongation (%) 450 ↑ 440 645

The tensile strength (N / mm < 2 >) and the elongation percentage (%) of these individual properties are the same as in the comparative graphs of Figs. 4 and 5 and the results of comparative tests of the hardnesses of the individual properties are shown in Table 2 below.

Properties KS F 3211 (2008) urethane rubber system
Class 1 Standard Specification Hard polyurethane flooring Super Micro Fiber + Rigid Polyurethane Flooring (Invention) Hardness (Shore A) 50 to 70 70 ~ 80 75 ~ 85

The results of the analysis of the individual property items are as follows.

First, the tensile strength and elongation ratio of the KS standard of the urethane waterproofing material at the time of the Vadic construction of the building structure with the superficial microorganism fiber (rigid polyurethane flooring) according to the present invention are greatly improved And it is superior to the conventional exposed urethane waterproofing material.

Next, when looking at the hardness, it is highly likely that the waterproof coating will be damaged due to work or human walking. However, since the hardness of the desktop adjuster (super micro fiber + rigid polyurethane flooring) according to the present invention is high, Can be lowered.

In addition, as for the adhesion force with the concrete base surface, the base adjusting material according to the present invention reinforced with the super hard coke fiber as the main base material of the hard urethane is higher than the existing KS exposure waterproofing material It has the advantage of reducing the cause of defects such as bulging, lifting and so on.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Various modifications may be made by those skilled in the art.

10: Structure 20: Lower layer
30: primary layer 40: primary layer
50: finish layer S100: background treatment process
S110: Undercoat layer forming step S120: Primary intermediate layer forming step
S130: Secondary intermediate layer forming step S140: Upper layer forming step

Claims

A first step of forming a primer layer by applying a primer to the surface of the structure;
Wherein the urethane resin comprises 10 to 30% by weight of PPG (Polypropylene Glycol) and 5 to 20% by weight of TDI (Toluene Diisocyanate) or MDI (Methane Diisocyanate), wherein the urethane resin is mixed with urethane resin at a ratio of 1000: A second step of forming a primary intermediate layer by applying a base adjusting agent containing 30 to 50 wt% of calcium carbonate and 0.01 to 5 wt% of a catalyst;
A third step of applying a urethane resin or a polyurea resin to the surface of the primary intermediate layer to form a secondary intermediate layer;
And a fourth step of applying a urethane resin or a polyurea resin to the surface of the secondary intermediate layer to form a top layer.

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