KR100586037B1 - Eco-friendly urethane sheet and its manufacturing method - Google Patents

Abstract

The present invention relates to a urethane sheet and a manufacturing method thereof, and more particularly, toluene diisocyanate, phthalate plasticizer, metal catalyst, 4,4 'methylene bis [2-chloroaniline], coloring pigments, etc. In order to achieve the above object, the present invention provides a free isocyanate content of diphenylmethane diisocyanate and polyol or polyether polyol having a low vapor pressure. And a polyol mixture used as a curing agent for forming a urethane elastic coating film by reacting the urethane prepolymer with% and the free isocyanate at the end of the urethane prepolymer. In the polyol mixture used as a curing agent, dimethylthiotoluenediamine as a chain extender is contained in a weight ratio of 2 to 5% of the total weight of the curing agent, and as a filler, natural mineral powders such as ocher and gemstone are 10 to 10 to the total weight of the curing agent. It relates to a urethane sheet characterized in that it is further included in the 70% range.

Urethane Sheet, Chain Extender

Description

 Eco-friendly urethane sheet and its manufacturing method {Pro-environmental Urethane Sheet and The Process}

The present invention relates to a urethane sheet and a method for manufacturing the same, and more particularly, to a urethane sheet and a method for manufacturing the same, which can be widely used in various flooring or decorative materials, including track and sports facilities.

Polyurethane refers to a polymer produced by the polymer addition reaction of a compound having at least two hydroxyl groups (-OH) and a polyfunctional isocyanate (-NCO). Generally, polyurethane is divided into three groups of isocyanates, polyols and other additives, and various kinds of polyurethanes are made according to the types and blending ratios of these components. The first group of polyurethanes consists of diisocyanates and polyisocyanates in isocyanates. The second group contains polyols and chain extenders such as diols and triols. extenders and crosslinkers and water, and the third group of catalysts, surfactants, fillers, blowing agents, and other additives (Miscellaneous) that do not react with the above. There are non-reactive components such as additives. The method for producing a urethane sheet using the polyurethane components as described above is generally a polyol mixture used as a curing agent consisting of a polyol and a chain extender, a plasticizer, a reaction catalyst, an antifoaming agent, a stabilizer, etc. in a urethane prepolymer composed of an isocyanate group and a polyol. It is manufactured by mixing according to the compounding ratio.

In general, when manufacturing a flooring material for sports facilities using urethane, as shown in the Republic of Korea Patent Registration (Registration No. 10-0425027), the urethane prepolymer is based on the isocyanate prepolymer obtained by polymerizing toluene diisocyanate and polyetherpolyol. In addition, the polyol mixture used as a curing agent is composed of polyether polyol and 4,4 'methylene bis [2-chloroaniline] (commonly referred to as MOCA) as a chain extender, and calcium carbonate as a filler and dioctyl as a plasticizer. Phthalate, a reaction catalyst, is made by mixing lead oxalate with lead content of 24 to 30% and coloring pigment and stabilizer. Then, the urethane prepolymer and the polyol mixture used as a curing agent are mixed at an appropriate weight ratio to uniformly coat the underlying layer to form a urethane sheet for sports facilities.

As described above, the method of manufacturing flooring material for athletic facilities using urethane is not only a land track but also a tennis court, a basketball court, a volleyball court, and the like, and the coating film thickness and hardness of the sheet are constructed by the urethane resin manufactured through the same process.

However, it is also true that the urethane flooring of the method used to date has poses a danger to the environment and the human body by several raw materials used in the production of urethane. In other words, the urethane prepolymer used as the main material uses toluene diisocyanate and polyether polyol as main components, and the toluene diisocyanate is a highly volatile substance, which is harmful to workers by the free isocyanate contained in the urethane prepolymer, which may be a safety problem. In addition, even after the urethane sheet is formed, the safety of this has not yet been identified, and the use of sports facilities has been raised.

In addition, 4,4'methylene bis [2-chloroaniline] is a dioxin-inducing substance defined as an endocrine disruptor by the chlorine group (cl group) present in the molecule. It is a known and carcinogen that is restricted to use in developed countries such as Europe.

Plasticizer dioctylphthalate (diechyl phthalate DOP or DEHP), which is used to lower the viscosity, belongs to the same group as toxic to cadmium and is known to be a substance that can impair human fertility after prolonged exposure to the human body.

In addition, the lead-based catalyst widely used as the reaction catalyst of the main agent and the curing agent is a heavy metal-based material, which can seriously affect the human body, and chromium is used in some pigmented pigments.

As such, the flooring material for sports facilities formed with urethane has been continuously raised despite its advantages such as excellent elasticity, abrasion resistance, ease of maintenance, and all-weather use. Considering the fact that the respiratory rate is much higher than other flooring materials, the solution to this problem is an urgent task.

Therefore, the present inventors use the diphenylmethane diisocyanate having a low vapor pressure instead of toluene diisocyanate as isocyanate, which is less harmful to the human body. ② The chain extender 4,4 'methylene bis [2-chloro Aniline] was used, and a number of experiments were carried out to produce a curing agent system without a reaction catalyst and a coloring agent without coloring pigments, using a plasticizer other than phthalate as a plasticizer. . Of course, as well as the production of environmentally friendly urethane sheet with less harmful to the human body as well as the advantages of the excellent elasticity, abrasion resistance, ease of maintenance and the like of the existing urethane flooring aimed to be above the equivalent level of the existing urethane flooring. .

In order to achieve the above object, the present invention is toluene diisocyanate, phthalate plasticizer, 4,4 'methylene bis [2-chloroaniline] chain in the components of the mixture of the urethane prepolymer used as the subject and the polyol mixture used as the curing agent. An environmentally friendly urethane sheet containing no extender, a metal catalyst, and a coloring pigment and a process for manufacturing the same are proposed.

The urethane sheet proposed by the present invention reacts with a urethane prepolymer having a free isocyanate content of 2 to 10% including diphenylmethane diisocyanate and polyol having a low vapor pressure and the free isocyanate at the end of the urethane prepolymer to form a urethane elastic coating film. It consists of a polyol mixture used as a curing agent.

Since the diphenylmethane diisocyanate is not harmful to the human body and is faster in reactivity than toluene diisocyanate, it is a main technical feature of the present invention to secure pot life that can be used on-site without a separate metal catalyst.

More specifically, in the urethane sheet proposed by the present invention, the polyol included to form the urethane prepolymer includes polypropylene glycol, polypropylene ethylene glycol or polyoxytetramethylene glycol having 2 to 3 activated hydrogen groups and a molecular weight of 1000 to 5000. It comprises a polyether polyol such as.

The polyol may be in the form of a triol or diol by combining with an isocyanate of a urethane prepolymer, preferably polypropylene glycol, polypropylene ethylene glycol or polyoxytetramethyl having 2 to 3 activated hydrogen groups and a molecular weight of 1000 to 5000. It is a main technical feature of this invention that it is a polyether polyol like len glycol.

Another urethane sheet proposed by the present invention reacts with a urethane prepolymer having a free isocyanate content of 2 to 10% comprising diphenylmethane diisocyanate and polyol or polyether polyol having a low vapor pressure, and a free isocyanate at the end of the urethane prepolymer. In the urethane sheet comprising a polyol mixture used as a curing agent for forming the urethane elastic coating film, the polyol mixture used as the curing agent is included in the amine chain extender.

By adding the above-mentioned amine chain extender to the polyol mixture used as a curing agent to prepare a urethane resin, it is possible to control the reactivity of diphenylmethane diisocyanate (MDI) and to reduce the probability of defect generation during construction.

Another urethane sheet proposed by the present invention reacts with a urethane prepolymer having a free isocyanate content of 2 to 10% comprising diphenylmethane diisocyanate with low vapor pressure and a polyol or polyether polyol and a glass isocyanate at the end of the urethane prepolymer. In the urethane sheet comprising a polyol mixture used as a curing agent to form a urethane elastic coating film, dimethylthio toluenediamine is contained in the polyol mixture used as the curing agent in 2 to 5% of the total weight of the curing agent.

As the amine chain extender, dimethyltoluenediamine does not contain a chlorine group, which is a carcinogen, and does not have a relatively fast reactivity with the free isocyanate of the subject, so that an appropriate pot life may be optimally secured at the work site. According to the main technical features of the present invention that the amine can be adjusted to suit the purpose of use.

In addition, another urethane sheet proposed by the present invention reacts with a urethane prepolymer having a free isocyanate content of 2 to 10% comprising diphenylmethane diisocyanate with low vapor pressure and a polyol or polyether polyol and a glass isocyanate at the end of the urethane prepolymer. In the urethane sheet comprising a polyol mixture used as a curing agent to form a urethane elastic coating film, the polyol mixture used as the curing agent comprises a natural mineral powder having its own color in 10 to 70% of the total weight of the curing agent.

By using a natural mineral powder having its own color as a filler in the urethane sheet, each color is expressed in its own color, and thus, color raw materials may not be used. Therefore, the manufacturing process and the unit cost of the urethane sheet may be reduced, as well as contained in the colored raw material. The same mechanical properties were achieved without the hazards of heavy metals.

In more detail, the urethane sheet proposed by the present invention includes the above-mentioned urethane sheet, wherein the filler having its own color is made of ocher powder, ceramic powder, ganban stone powder, jadeite powder, chlorite powder or porcelain powder.

In the case of using ocher powder as a filler as described above, the urethane sheet expresses the yellowish brown color as the general soil, and in addition, the elvan powder and the ceramic powder, which have their own colors, are also the same as the general filler if the weight ratio of the curing agent is properly controlled. It will be possible to manufacture a urethane sheet while having mechanical properties.

In addition, another urethane sheet proposed by the present invention is a urethane prepolymer having a free isocyanate content of 2 to 10%, including diphenylmethane diisocyanate with low vapor pressure and a polyol or polyether polyol, and a glass isocyanate at the end of the urethane prepolymer. A urethane sheet comprising a polyol mixture used as a curing agent to react to form a urethane elastic coating film, wherein the polyol mixture used as the curing agent contains dipropylene dibenzoate as an ester plasticizer at 5 to 20% of the total weight of the curing agent. It is done.

As the plasticizer, dipropylene dibenzoate is an ester plasticizer which is not harmful to the human body, unlike phthalate plasticizers generally used in the related art.

In order to more easily manufacture the urethane sheet as described above, the present invention dissolves diphenylmethane diisocyanate while passing nitrogen through a synthetic container from which moisture is removed, and then polypropylene glycol and an ester plasticizer are added and mixed under nitrogen stream. The urethane sheet production method is characterized by producing a urethane prepolymer at a reaction temperature of 80 ± 2 ℃.

The urethane prepolymer production method is characterized in that the polyphenyl glycol and dipropylene dibenzoate which is an ester plasticizer after addition of the diphenyl methine diisocyanate is dissolved by heating.

Next, the detailed structure and components of the eco-friendly urethane sheet according to the present invention and a manufacturing method thereof will be described in detail based on the preferred embodiment.

Isocyanate is a low vapor pressure diphenylmethane diisocyanate as the subject of the urethane prepolymer to complete the present invention, and in this case, monodiphenylmethane diisocyanate, polymer diphenylmethane diisocyanate, modified diphenylmethane diisocyanate can be used. At least one of them can be selected and used. As the polyol bonded to the main isocyanate to complete the urethane prepolymer, a polyether polyol having 2 to 3 activated hydrogen groups and a molecular weight of 1000 to 5000 is preferable. The selected raw material is synthesized in a synthesis vessel under a nitrogen stream at a temperature ranging from 60 to 90 ° C. for 4 to 8 hours to prepare a urethane prepolymer. The free isocyanate content of the synthesized urethane prepolymer is preferably in the range of 2 to 10%, of which 3 to 7 % Is more preferred. If the free isocyanate content is less than 2%, the viscosity is high, making it difficult to use in the field. If the free isocyanate content is more than 10%, the free isocyanate may react with moisture contained in the air or in the curing agent, which may cause swelling of the coating film and deteriorate storage stability. .

Conventionally, in preparing an urethane flooring composition having elasticity, it is common to use toluene diisocyanate (TDI) as the isocyanate of the urethane prepolymer, but toluene diisocyanate is a highly volatile substance, and the worker is freed by the free isocyanate contained in the urethane prepolymer. It could be harmful to your safety. However, the use of diphenylmethane diisocyanate according to the present invention is not harmful to the human body and increases reactivity compared to toluene diisocyanate, thereby ensuring pot life that can be used on-site without a separate metal catalyst.

In general, urethane prepolymers are generally prepared by reacting isocyanates with polyols (diols or triols), but it is also possible to selectively use plasticizers or chain extenders depending on the purpose of use. As the chain extender to be added, 1.3 butanediol, 1.4 butanediol, monoethylene glycol, diethylene glycol, trimethylpropanol, neopentyl glycol, and the like can be used. Among them, appropriately selected according to the purpose of the final urethane coating film is used. desirable.

The use of toluene diisocyanate (TDI) as the isocyanate of the urethane prepolymer was harmful to the workers and caused a safety problem. Since phenylmethane diisocyanate (MDI) has a faster reaction than toluene diisocyanate (TDI), it has a technical problem that only 4,4 'methylene bis [2-chloroaniline] (MOCA) can be used as a chain extender. In addition, it is difficult to reactive control as compared to the toluene diisocyanate (TDI), etc., so fast compared to the reaction of toluene diisocyanate (TDI) with the moisture in the air that CO ₂ gas by reaction with water generated in the construction process by the air moisture It was true that the probability of defect occurrence was high. For this reason, urethane flooring is conventionally manufactured using toluene diisocyanate (TDI) rather than diphenylmethane diisocyanate (MDI). Therefore, the inventors have been able to manufacture urethane sheets using diphenylmethane diisocyanate (MDI) in manufacturing flooring materials for athletic facilities after years of research, thereby inventing environmentally friendly urethane flooring materials. It was possible to control the reactivity of diphenylmethane diisocyanate (MDI) in the manufacturing process and to reduce the probability of defects during the construction process to prepare a urethane prepolymer using diphenylmethane diisocyanate (MDI) and carcinogens as chain extenders An amine chain extender containing no phosphorus chlorine group was added to the polyol mixture used as a curing agent to produce a urethane resin. The amine chain extender described above in the present invention controls the reactivity of the isocyanate group by combining with diphenylmethane diisocyanate to form a urea group separately from the polyol of the urethane prepolymer. In addition, after the amine-based chain extender is combined with diphenylmethane diisocyanate, the excess isocyanate is combined with a polyol mixture used as a curing agent to form a urethane resin layer, thereby regulating the reaction with moisture in the air to suppress gas generation. The probability of occurrence can be reduced.

The polyol mixture as a curing agent reacts with the free isocyanate at the end of the urethane prepolymer to form a urethane elastic coating film, and is prepared by mixing a polyol with a chain extender, a filler, a plasticizer, a stabilizer and the like. For the purpose of the invention, since no harmful substances should be included, it is preferable to prepare 4,4'methylenebis [2-chloroaniline], phthalate plasticizer, metal catalyst, coloring pigment, etc. which are commonly used. .

For this purpose, as a polyol, the molecular weight is 1000-5000 and polyether polyol, such as 2 or 3 polypropylene glycol, polypropylene ethylene glycol, polyoxy tetramethylene glycol, is preferable.

As the chain extender, a glycol-based chain extender and an amine-based chain extender may be used. The glycol-based chain extender may be used by adjusting an appropriate amount of glycol suitable for the purpose of use among the glycols used in preparing the urethane prepolymer. As the amines, it is preferable that the reactor uses two to three primary or secondary amines among the amines which do not contain a chlorine group (cl group) which is a carcinogen in the molecule. Among these amines, diethyl toluene diamine, polypropylene diamine, isophorone diamine, diphenylmethanediamine, metaxylenediamine, dimethylthiotoluenediamine, monoethanolamine, diethanolamine, benzene secondary diamine, etc. are used. It is preferable.

Since the amine chain extender has a great effect on the mechanical properties of the final urethane coating film, and has a great influence on the reaction with the free isocyanate of the main material, the type and amount of the amine used are mixed with the physical properties of the final coating film and the main and hardeners. The pot life and curing time of the test should be carefully considered. Therefore, the present inventors closely examine the amine chain extender, and as a result, the reactivity is not relatively fast, so that the pot life of about 1 hour after mixing, which is a pot life at which work can be performed at the work site, can be secured. It was concluded that dimethylthiotoluenediamine is suitable as a tunable amine. In addition, it was concluded that the amount of use thereof is 1 to 10% of the total amount of the curing agent by weight ratio, of which 2 to 5% is more preferable. If the amount is less than 1%, the pot life could be secured sufficiently, but the mechanical properties would be lowered, and if more than 10% was used, the physical properties of the coating film could be sufficiently secured, but the pot life would be less than 10 minutes, making field work difficult. This will be described in detail in Examples and Comparative Examples.

As a filler, calcium carbonate, calcium carbonate containing fatty acid, clay, talc, mica or barium sulfate can be used. However, when the urethane coating film is formed using the same, the color becomes white due to the characteristics of the filler. Pigments must be added. As such pigments may include pigments containing heavy metals such as chromium as described above, in the present invention, fillers having their own colors are selected in order not to use pigments. To express, finely divided and dehydrated ocher powder, ceramic powder, elvan powder, jadeite powder, chlorite powder or pottery powder were used. The amount of the filler used is preferably about 10 to 70% of the total weight of the curing agent, more preferably about 20 to 50%.

The plasticizer added to lower the viscosity and plasticize the coating film can be classified into phthalate-based, ester-based, phosphite-based, epoxy-based, etc., and phthalate-based esters are not harmful to humans because they are harmful to humans as described above. It is preferable to use, and it is preferable to use a dipropylene glycol dibenzoate or diethylene glycol dibenzoate or the like. The amount of the plasticizer to be used should be used by comprehensively examining the viscosity of the curing agent system, the mechanical properties of the final coating, etc., and it is generally preferable to use it within 5 to 20% of the total weight of the curing agent.

When the reaction is performed with the urethane curing agent and the prepolymer thus prepared, the urethane coating film is formed by reacting with the isocyanate of the urethane prepolymer, the polyol of the curing agent, and the chain extender, but the isocyanate at the end of the prepolymer reacts with moisture contained in the air or in the curing agent. Since it may cause defects such as swelling of the water absorbent is added to the curing agent. At this time, as a water absorbing agent, molecular sieves such as zeolite, paratoluenesulfonyl isocyanate (PTSI), triethylol formate, formidine acetate and the like can be selected and used, and the amount is 0.5 to 10% by weight of the total weight of the curing agent. Is preferred.

In addition, an ultraviolet stabilizer such as hindered amine may be added to prevent deterioration of the coating due to ultraviolet rays, and an antifoaming agent may be added to remove bubbles existing in the coating after construction. These can be suitably used in the type and amount used in the production of a urethane curing agent in general, it is generally preferred to use within the range of 0.1 to 0.5% by weight of the total weight of the curing agent.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

First, in order to prepare a urethane sheet according to the present invention, a urethane resin was prepared by mixing a polyol mixture used as a urethane prepolymer and a curing agent.

Example 1

Urethane prepolymers were prepared as follows. 225 g of solid monodiphenylmethine diisocyanate was added while passing nitrogen through a synthetic container from which moisture was removed, and the mixture was heated to 45 ° C. for 30 minutes to dissolve diphenylmethane diisocyanate. After confirming the dissolution, 304 g of polypropylene glycol triol having an average molecular weight of 3000 and 304 g of polypropylene glycol diol having an average molecular weight of 2000 were added and mixed with 167 g of an ester plasticizer as a plasticizer. Urethane prepolymers having 5% free isocyanate content were prepared.

And a polyol mixture used as a curing agent was prepared as follows. 30 parts by weight of polypropylene glycol diol and triol (PPG) having an average equivalent weight of 1000 parts, 1 part by weight of dimethylthiotoluenediamine, 1 part by weight of a glycol chain extender, an average particle diameter of 10 µm, and a water content of 0.3% 50 parts by weight of ocher powder, 5 parts by weight of an ester plasticizer, 5 parts by weight of zeolite as a moisture absorbent, 0.5 parts by weight of an antifoaming agent, and 0.5 parts by weight of other UV stabilizers were added, followed by dispersion mixing for 1 hour to prepare a curing agent.

The urethane prepolymer and the polyol mixture thus prepared are mixed well at a predetermined mixing ratio (NCO equivalent / OH equivalent = 1.2 / 1) to prevent bubbles from entering and then in a room of standard condition (25 ± 2 ° C., 60 ± 20% RH). After curing for 1 week, the mechanical properties of KSM-6518 vulcanized rubber were measured according to the physical test method and the results are shown in Table 1.

[Examples 2 to 7]

In preparing the polyol mixture used as the curing agent of Example 1, 2 to 7 parts by weight of dimethylthiotoluenediamine was added, and the polyol and other raw materials were added in the same kind and amount as in Example 1, and the curing agent was added in the same manner. Prepared. The main urethane prepolymer was a prepolymer prepared in Example 1 and tested in Example 1 test method and the results are shown in Table 1.

Table 1. Results according to Examples 1-7

  ※ ① Dimethylthiotoluenediamine

    ② dipropylene dibenzoate

    ③ BYK-054

    ④ Time to reach 100,000cps after mixing at 25 ℃

    ⑤ William's Wear Tester

In general, pot life, hardness, tensile strength, tear strength, and elongation, which are recognized as important physical properties in athletic flooring, including ground flooring for athletic facilities, meet the following criteria as shown in Table 2 below. It is considered to be suitable for flooring.

Table 2. Physical Characteristics of Physical Floors

Looking at the physical properties of Examples 1 to 7 of the present invention shown in Table 1 on the basis of Table 2, Example 1 according to the present invention does not meet the standard value of hardness, tensile strength, tear strength and Example 6 And 7 slightly exceed the reference value only in hardness. In general, it can be seen that Examples 1 to 7 of the present invention correspond to the object of the present invention, and Examples 2 to 5 further correspond to the object of the present invention.

Therefore, when manufacturing the urethane sheet for physical education facilities according to the present invention, it is preferable that dimethylthiotoluenediamine is included as 1-10% of the total weight of the curing agent as a chain extender added to the polyol mixture used as a curing agent constituting the resin layer. It can be seen that the most preferable is contained in 2 to 5% of the total weight of the curing agent.

As an important feature of the present invention, the excellent effect of adding dimethylthiotoluenediamine to the polyol mixture used as a curing agent in a urethane sheet containing an amine chain extender is as described in Comparative Examples 1 to 3 below. The urethane sheet was prepared by adding zero diethylluenediamine, isophoronediamine or polypropylene diamine, and tested by the test method of Example 1, and comparing the results clearly shows the excellent effect of the present invention. Comparative Example was prepared in Example 3 compared with the addition of 3 parts by weight of dimethylthio toluenediamine as the amine chain extender.

Comparative Example 1

In Example 3, 3 parts by weight of dimethyltoluenediamine was added to the polyol mixture as a curing agent instead of dimethylthiotoluenediamine as an amine chain extender, and the polyol and other raw materials were added in the same kind and amount as in Example 3, and in the same manner. A curing agent was prepared. The main urethane prepolymer was prepared using the prepolymer prepared in Example 1, and was tested by the test method of Example 1, and the results are shown in Table 2.

Comparative Example 2

3 parts by weight of isophoronediamine was added to the polyol mixture as the curing agent in Example 3 as an amine chain extender instead of dimethylthiotoluenediamine, and the polyol and other raw materials were added in the same kind and amount as in Example 3, and the curing agent was added in the same manner. Was prepared. The main urethane prepolymer was prepared using the prepolymer prepared in Example 1, and was tested by the test method of Example 1, and the results are shown in Table 2.

Comparative Example 3

In Example 3, 3 parts by weight of polypropylenediamine (Jeffamine D-230 manufactured by HUNTSMAN) was added to the polyol mixture as a curing agent instead of dimethylthiotoluenediamine as the amine chain extender. Amounts were added and hardeners were prepared in the same manner. The main urethane prepolymer was a prepolymer prepared in Example 1 and tested in Example 1 test method and the results are shown in Table 2.

Table 3. Results according to Comparative Examples 1 to 3

As shown in Table 3 above, when the urethane sheet was prepared by using dimethylthiotoluenediamine as the amine chain extender but by adding dimethyltoluenediamine, isophoronediamine or polypropylenediamine, the amine chain extender As it is rapidly reacted with the isocyanate of the prepolymer, it was difficult to measure the pot life as shown in Table 3 above. In addition, in the case of the polyol that did not react due to the large difference in reactivity between the amine and the polyol, the reaction time was not significant because the reaction did not occur until the next day.

As can be seen from the above, the present inventors have thoroughly examined various amine chain extenders, and as a result, they do not include carcinogens, and thus the reactivity is relatively fast. It was concluded that dimethylthiotoluenediamine is suitable as an amine that can be adjusted to suit the purpose of use and the physical properties of the final coating film. In addition, it was concluded that the amount of use thereof is 1 to 10% of the total amount of the curing agent by weight ratio, of which 2 to 5% is more preferable.

Furthermore, in order to control the reactivity of diphenylmethane diisocyanate (MDI) in the process of manufacturing urethane sheet using diphenylmethane diisocyanate (MDI) and to reduce the probability of defects in the construction process, dimethylthiotoluene is used as a chain extender. It has been found that by adding diamine to a polyol mixture used as a curing agent to produce a urethane resin, an eco-friendly urethane sheet can be produced without a metal catalyst.

The present invention also relates to a urethane sheet comprising a natural mineral powder filler having its own color in the polyol mixture used as a curing agent in an amount of 10 to 70% of the total weight of the curing agent. More specifically, the natural mineral powder filler is a urethane sheet, characterized in that it is ocher powder, ceramic powder, ganban stone powder, gemstone powder, chlorite powder or pottery powder. In Examples 1 to 7 of the present invention described an example of using ocher powder as a filler, even when using agglomerate powder or ceramic powder, it was found that a separate coloring pigment is not necessary because each expresses a unique color. Mechanical properties are shown.

In the following, by using a natural mineral powder filler having its own color as a filler according to the present invention, a filler generally used in the past to demonstrate the effect of producing a urethane sheet that can have a color without a separate pigment pigment To produce a comparative example with the present invention.

The filler refers to a substance applied to the base material to improve the overall properties such as strength and durability, or an inert substance such as calcium carbonate or clay added for the purpose of increasing, increasing, or reducing the cost of the product. I also speak. That is, the material applied to the base material in order to improve the overall properties, such as physical properties of the polymer compound is generally referred to as a filler, and includes acting by adjusting the hardness, strength, elongation or viscosity. Comparative Examples 4 to 7 show that the present invention has an excellent effect compared to the prior art by comparing the results of using heavy calcium carbonate as a filler and the results of the examples according to the present invention. Comparative Example was prepared in Example 3 compared with when adding 50 parts by weight of ocher powder as a filler.

[Comparative Example 4]

In Example 3, 50 parts by weight of heavy calcium carbonate (average particle diameter: 10 µm) was added to the polyol mixture as a curing agent as a filler, and the amine chain extender dimethylthiotoluenediamine and other raw materials were the same kind and amount as in Example 3. Was added and a curing agent was prepared in the same manner. The main urethane prepolymer was prepared using the prepolymer prepared in Example 1, and was tested by the test method of Example 1, and the results are shown in Table 4.

[Comparative Example 5]

In Example 3, 50 parts by weight of Talc (average particle diameter: 10 µm) was added as a filler to the polyol mixture which is a curing agent, and amine chain extender dimethylthiotoluenediamine and other raw materials were added in the same kind and amount as in Example 3. And a curing agent was prepared in the same manner. The main urethane prepolymer was prepared using the prepolymer prepared in Example 1, and was tested by the test method of Example 1, and the results are shown in Table 4.

Comparative Example 6

In Example 3, 50 parts by weight of the total weight of the curing agent was added to the polyol mixture, which is a curing agent, in a 50:50 weight ratio of ocher and heavy calcium carbonate (average particle diameter: 10 mu m), and the amine chain extender dimethylthiotoluenediamine and others. Raw materials were added in the same kind and amount as in Example 3, and a curing agent was prepared in the same manner. The main urethane prepolymer was prepared using the prepolymer prepared in Example 1, and was tested by the test method of Example 1, and the results are shown in Table 4.

Table 4. Comparison of results according to Comparative Examples 4 to 6 with Example 3

※ The wear loss was tested or verified by William's wear tester.

As shown in Table 4, when general fillers (heavy calcium carbonate, Talc, etc.) were used as in Examples 4 and 5, the color became white. Therefore, it can be seen that the coloring pigments are required for the purpose of manufacturing the urethane flooring material, and in Example 3 and Comparative Example 6, since the same yellowish brown color as the general soil was confirmed, no additional coloring pigments were required.

When the urethane prepolymer prepared as described above and the polyol mixture used as a curing agent are mixed within the equivalence ratio of the main agent / curing agent within the range of 1.1 to 1.3, the urethane prepolymer is highly reactive diphenylmethane diisocyanate, so it is used on site without a separate metal catalyst. As long as 40 ~ 70 minutes of pot life is possible, the urethane cured coating film does not contain phthalate plasticizer, metal catalyst, coloring pigment, 4,4 'methylene bis [2-chloroaniline], etc. It can form urethane flooring with human safety and can provide urethane flooring that can express moderate elasticity, abrasion resistance, mechanical strength, etc. to athletic facilities such as tracks.

Claims (8)

(delete) A polyol mixture used as a curing agent for forming a urethane elastic coating film by reacting a urethane prepolymer having a free isocyanate content of 2 to 10% and a free isocyanate at the end of the urethane prepolymer with a low vapor pressure diphenylmethane diisocyanate and a polyol. In the urethane sheet containing, The polyol is a urethane sheet, characterized in that a polyether polyol such as polypropylene glycol, polypropylene ethylene glycol or polyoxytetramethylene glycol having a molecular weight of 1000 to 5000 having 2 to 3 activated hydrogen groups. The urethane sheet according to claim 2, wherein the polyol mixture used as the curing agent contains an amine chain extender. The urethane sheet according to claim 3, wherein the amine-based chain extender is dimethylthiotoluenediamine and is contained in an amount of 1 to 10% of the total weight of the curing agent. The urethane sheet according to claim 2, wherein the polyol mixture used as the curing agent contains 10 to 70% of the total weight of the curing agent. The urethane sheet according to claim 5, wherein the natural mineral powder having its own color is ocher powder, ceramic powder, elvan powder, jadeite powder, chlorite powder or porcelain powder. The urethane sheet according to claim 2, wherein the polyol mixture used as the curing agent contains dipropylene dibenzoate as an ester plasticizer at 5 to 20% of the total weight of the curing agent. Diphenylmethane diisocyanate is heated and dissolved while passing nitrogen through a synthetic container from which water is removed, and then polypropylene glycol and an ester plasticizer are added and mixed to prepare a urethane prepolymer at a reaction temperature of 80 ± 2 ° C. under a nitrogen stream. Urethane sheet manufacturing method.