A storage-stable polyisocyanate composition based on cyclohexyl dimethylene diisocyanate and a method of making the same

Abstract

The present application relates to a kind of based on cyclohexyl dimethylene diisocyanate storage stable polyisocyanate composition and its preparation method.The composition is prepared from cyclohexyl dimethylene diisocyanate monomer, meets (1) its monomer raw material has the following composition relationship: (a) 1, 3-cyclohexyl dimethylene diisocyanate content is 95.0%-99.9%;(b) 1, 4-cyclohexyl dimethylene diisocyanate content is 0.1%-5.0%;(2) with polyisocyanate composition as total mass, composition meets the content of dimer and biuret formed by cyclohexyl dimethylene diisocyanate is between 0.2%-4.0%.The polyisocyanate composition prepared by the present application has good storage stability, the viscosity growth value is less than 10% when stored at room temperature for 12 months, the turbidity increase is not higher than 0.2NTU, and the product appearance has no any deterioration phenomenon;Meanwhile, also have good drying speed, greatly improve the construction speed of coating.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polymer materials, and particularly relates to a storage-stable polyisocyanate composition based on cyclohexyl dimethylene diisocyanate and a preparation method thereof. BACKGROUND

[0002] Polyurethane materials are widely used in light industry, electronics, textiles, medical treatment, construction, automobile, aviation and other fields due to their good weather resistance, wear resistance and wide adjustable range of mechanical properties. However, the isocyanate group used to form the polyurethane material is active, and generally has a short shelf life and is unstable in storage. In particular, the isocyanate composition containing solvent or emulsion has strict requirements on storage conditions and storage time, otherwise, phenomena such as increase in turbidity, significant reduction in system transparency and increase in viscosity may occur.

[0003] Patent CN105860025 provides a storage-stable isocyanate composition by preparing microcapsules containing isocyanate groups. This method needs to introduce an aqueous phase as a dispersed phase, and needs to go through multiple steps such as emulsification, suction filtration, water washing and air drying to obtain solid capsules, which is complicated.

[0004] Patent CN106084182 adds N-heterocyclic carbene metal complexes during the reaction process to ensure that the product can be stably stored for at least 6 months when the isocyanate composition is diluted to 75wt% solid content, and the increase in isocyanate monomer content is less than 0.15wt%. This method is relatively simple, but the additional stabilizer may migrate out during terminal use, which may harm the environment or human health.

[0005] Patent CN110078889 purifies the p-tolylene diisocyanate monomer to make the dichloroimine content less than 3ppm. This method avoids the drawbacks of additional stabilizers, and produces a p-tolylene diisocyanate-based polyisocyanate composition solution with stable storage color number. However, further purification of industrial raw materials means consuming more energy and increasing economic costs, and only the color number stability is improved.

[0006] The isocyanate composition based on cyclohexyl dimethylene diisocyanate, such as the commonly used isocyanurate type or the trimethylolpropane modified urethane type product, is mostly in solid form at room temperature, so it is usually supplied and used in a solvent-containing form. During transportation or use, the product is easily affected by external factors and the turbidity and viscosity indexes increase.

[0007] Therefore, it is necessary to seek an isocyanate composition based on cyclohexyl dimethylene diisocyanate and a preparation method thereof to ensure good storage stability. SUMMARY

[0008] The present application aims to provide a cyclohexyl dimethylene diisocyanate storage-stable polyisocyanate composition and a preparation method thereof.

[0009] The present application is achieved by the following technical scheme: In the first aspect, the present application provides a cyclohexyl dimethylene diisocyanate storage-stable polyisocyanate composition.

[0010] The polyisocyanate composition is prepared from cyclohexyl dimethylene diisocyanate monomers, and the cyclohexyl dimethylene diisocyanate is composed of raw materials in the following composition relationship, accounting for the total mass:

[0011] (a) 1,3-cyclohexyl dimethylene diisocyanate content is 95.0%-99.9%.

[0012] (b) 1,4-cyclohexyl dimethylene diisocyanate content is 0.1%-5.0%.

[0013] In the present application, the specific composition of cyclohexyl dimethylene diisocyanate raw materials can be adjusted by commercial products 1,3-cyclohexyl dimethylene diisocyanate and 1,4-cyclohexyl dimethylene diisocyanate according to the mass ratio, or the precursors of the diisocyanate, 1,3-cyclohexyl dimethylene diamine and 1,4-cyclohexyl dimethylene diamine, can be directly used according to the mass adjustment to the following proportion:

[0014] (a) 1,3-cyclohexyl dimethylene diamine content is 95.0%-99.9%.

[0015] (b) 1,4-cyclohexyl dimethylene diamine content is 0.1%-5.0%.

[0016] Then, the mixed diamine precursor is subjected to phosgenation reaction and separated to obtain the raw material with the above composition. From the perspective of industrialization, it is more preferred to adjust the commercial products 1,3-cyclohexyl dimethylene diisocyanate and 1,4-cyclohexyl dimethylene diisocyanate according to the mass ratio.

[0017] The main reasons for the instability of the polyisocyanate composition product are that the product system is affected by the surrounding environment, such as moisture and oxygen in the air, and that the internal microstructure of the product tends to crystallize or polymerize. The present inventors have surprisingly found that when the raw material composition of cyclohexyl dimethylene diisocyanate is controlled within a specific range, 1,4-cyclohexyl dimethylene diisocyanate and 1,3-cyclohexyl dimethylene diisocyanate synergistically increase the polymer structure disorder degree of the system, thereby improving the anti-crystallization and compatibility performance of the product.

[0018] Furthermore, based on the total mass of the polyisocyanate composition, the composition satisfies that the sum of the content of the dimer formed by cyclohexyldimethylene diisocyanate and the biuret content is between 0.2% and 4.0%, preferably between 0.5% and 4.0%.

[0019] Furthermore, considering the ease of industrial application, the concentration limit for the sum of the dimer formed by cyclohexyl dimethylene diisocyanate and the biuret content is mainly applicable to the form containing solvent diluted to 75%, but is not limited to other scenarios. For example, after solvent removal, the limit range can be changed accordingly according to the specific situation, and such changes are well known to those skilled in the art.

[0020] To address the impact of moisture in the air, the microstructure of the product is adjusted by pre-treating cyclohexyldimethylene diisocyanate through partial dimerization and biuretization. This results in greater tolerance to flocculent matter and, due to increased resistance to the rightward reaction at room temperature, a polyisocyanate composition product with good storage stability can be obtained. Moreover, the process is simple and easy to control.

[0021] Furthermore, the glass transition temperature of the polyisocyanate composition is 20-60°C.

[0022] The glass transition temperature (Tg) is the temperature at which the glass state changes between a liquid and a glassy state. It is well known that Tg is a crucial factor in the properties of polymer coatings, but the concept of glass transition in isocyanate compositions remains relatively uncommon. Compositions with lower glass transition temperatures are advantageous for application because they do not rapidly harden and become brittle as the temperature decreases. However, polyisocyanate compositions with low glass transition temperatures experience reduced drying properties. Therefore, a specific range of Tg is defined to ensure good curing or drying properties for the polyisocyanate composition.

[0023] Further, the polyisocyanate composition refers to a modified composition obtained by polymerization or modification of cyclohexyldimethylene diisocyanate, preferably, the composition contains one or more of (a) isocyanurate group, (b) urea diketone group, (c) biuret group, (d) carbamate group, and (e) ureocarbamate group.

[0024] In a second aspect, the present invention further provides a method for preparing the above-mentioned polyisocyanate composition. It is characterized by comprising the following steps: adding cyclohexyldimethylene diisocyanate to a reaction vessel, adding distilled water first under an inert gas atmosphere, then raising the temperature for biuretization pretreatment, then cooling, and then partially cyclizing cyclohexyldimethylene diisocyanate in the presence of a trimerizing catalyst, terminating the trimerizing catalyst with a terminator at the end of the cyclization, and finally removing unreacted isocyanate monomers. Its characteristic condition is that (1) the monomer raw materials satisfy the following compositional relationship:

[0025] (a) The content of 1,3-cyclohexyldimethylene diisocyanate is 95.0%-99.9%.

[0026] (b) The content of 1,4-cyclohexyldimethylene diisocyanate is 0.1%-5.0%.

[0027] (2) Based on the total mass of the polyisocyanate composition, the composition satisfies that the sum of the content of the dimer formed by cyclohexyldimethylene diisocyanate and the biuret content is between 0.2% and 4.0%, preferably between 0.5% and 4.0%.

[0028] More preferably, the inert gas is nitrogen.

[0029] Furthermore, the catalyst is not particularly limited, but from the perspective of process stability, one or more of the following can be selected: trimethylhydroxyethylammonium, triethylhydroxypropylammonium, tetramethylammonium acetate, tetrabutylammonium acetate, tetramethylammonium propionate, tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriphenylphosphine chloride, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0030] In this invention, the catalyst is dissolved in a monool and / or diol to form a solution for use. The monool and / or diol includes, but is not limited to, methanol, ethanol, 1-propanol, 2-propanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-octanol, isooctanol, heptanol, 2-ethyl-1,3-hexanediol, 1,3-butanediol, and 1,4-butanediol, preferably one or more of 2-ethyl-1,3-hexanediol, n-butanol, hexanol, heptanol, and isooctanol.

[0031] Furthermore, the amount of distilled water used is 0.005%-0.5% based on the total amount of cyclohexyldimethylene diisocyanate, preferably 0.005%-0.1%.

[0032] More preferably, the biuretization treatment temperature is 120-160℃, and the biuretization time is 1-4h.

[0033] Furthermore, the trimerization reaction temperature of the present invention, also known as the cooling temperature after biuretization pretreatment, is selected from 40-100°C, preferably 60-90°C.

[0034] Furthermore, the terminating agent is one or more of the conventional benzoyl chloride, dibutyl phosphate, phosphoric acid, and diisooctyl phosphate, preferably dibutyl phosphate and / or diisooctyl phosphate.

[0035] Furthermore, the method for removing unreacted cyclohexyldimethylene diisocyanate by distillation can be any one of thin-film evaporation, falling film evaporation, short-path evaporation, or vacuum distillation, with thin-film evaporation being preferred.

[0036] Thin-film evaporation conditions are well known to those skilled in the art and can be routinely adjusted according to specific process differences. In this invention, the preferred conditions are a thin-film evaporator temperature of 110–180°C and a vacuum degree of 10–250 Pa.

[0037] Furthermore, the polyisocyanate composition of the present invention, except for very few special requirements, may not exist in solvent-diluted form. In other cases, it is diluted into a polyisocyanate composition solution using an inert solvent, preferably ethyl acetate, butyl acetate, acetone, butanone, chlorobenzene, xylene, dimethylformamide, etc., more preferably ethyl acetate and / or butyl acetate.

[0038] Another object of the present invention is to provide a polyurethane resin, said polyurethane resin being formed by reacting the polyisocyanate composition of the cyclohexyl dimethylene diisocyanate with a substance containing active hydrogen groups.

[0039] Furthermore, substances containing active hydrogen groups are well known to those skilled in the art, and any one or more of polyether polyols, polyester polyols, polycarbonate polyols, and acrylate polyols can be selected according to the actual application.

[0040] The beneficial effects of this invention are as follows:

[0041] (1) The storage stability of the polyisocyanate composition is greatly improved. After 12 months of storage at room temperature, the viscosity increase is less than 10%, the turbidity increase is not higher than 0.2 NTU, and there is no deterioration in the appearance of the product.

[0042] (2) Compared with the prior art, this composition ensures good storage stability and has a better drying speed, which greatly improves the construction speed of the coating. Detailed Implementation

[0043] To better understand the technical solution of the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0044] The key raw materials used in the following embodiments and comparative examples of this invention and their sources are as follows:

[0045] 1,3-Cyclohexyldimethylene diisocyanate (1,3-HXDI) was purchased from Wanhua Chemical Group Co., Ltd.

[0046] 1,4-Cyclohexyldimethylene diisocyanate (1,4-HXDI) was purchased from Mitsui Chemicals, Ltd., Japan.

[0047] Tetrabutylammonium hydroxide, cyclization catalyst, purchased from Evonik Chemical Industries Ltd.;

[0048] Benzyltrimethylammonium hydroxide, a cyclization catalyst, was purchased from Evonik Chemical Industries, Ltd.

[0049] Dioctyl phosphate, a terminator, was purchased from Tianjin Yongda Chemical Reagent Co., Ltd.

[0050] Dibutyl phosphate, a terminator, was purchased from Tianjin Yongda Chemical Reagent Co., Ltd.

[0051] Unless otherwise specified, all contents in this invention refer to mass content.

[0052] The relevant test methods in the following embodiments and comparative examples of this invention are as follows:

[0053] (1) Viscosity test: The dynamic viscosity at 25℃ was measured using a lamina viscometer (Brookfield DT-2).

[0054] (2) Turbidity test: The turbidity at 25℃ was tested using a HACH 2100N series turbidity meter.

[0055] (3) Glass transition temperature Tg: The Tg of the polyisocyanate composition was determined using a differential thermal analyzer (Seiko Instruments Inc., trade name DSC6220) at a heating rate of 20°C / min when the isocyanate composition was in solvent-free condition.

[0056] (4) Dimer and biuret content test: Using an AVANCE400 manufactured by Bruker Biospin, with deuterated chloroform (CDCl3) as solvent, the content of the sample (the prepared isocyanurate product) was determined at 60% mass concentration, 100 MHz, overnight scanning. 13 C nuclear magnetic resonance spectrum.

[0057] It should be noted that in the above determination, the following signals are integrated, and their content is determined from their values.

[0058] (a) Dimer structure: around δ157.8ppm

[0059] (b) Biuret structure: around δ 151.0 ppm

[0060] (c) Dimer to biuret content ratio: (Formula I + Formula II) / (Formula I + Formula II + other isocyanurate structures) = (Signal area of ​​Formula I structure + Signal area of ​​Formula II structure) / (Signal area of ​​Formula I structure + Signal area of ​​Formula II structure + Signal area of ​​other isocyanurate structures)

[0061] Wherein, Formula I represents the dimer structure, and its structural formula is as follows:

[0062]

[0063] In structure I, R1 represents the residual structure of any 1,3-cyclohexyldimethylene diisocyanate or 1,4-cyclohexyldimethylene diisocyanate after removing the NCOs at both ends.

[0064] Formula II represents a biuret structure, and its structural formula is as follows:

[0065]

[0066] In structure II, R2 represents the residual structure of any 1,3-cyclohexyldimethylene diisocyanate or 1,4-cyclohexyldimethylene diisocyanate after removing the NCOs at both ends.

[0067] Other isocyanurate structures mainly refer to those containing the following structural units:

[0068]

[0069] In other isocyanurate structures, R3 represents the residual structure of any 1,3-cyclohexyldimethylene diisocyanate or 1,4-cyclohexyldimethylene diisocyanate after removing the NCOs at both ends.

[0070] (5) Drying test: The polyisocyanate composition and the active hydrogen-containing resin AC-1370 were mixed at the ratio of isocyanate groups to hydroxyl groups NCO / OH = 1.05-1.1, and equal masses of xylene and ethyl acetate were added as diluents. The mass ratio of the diluent was 35% based on the total mass of the isocyanate composition, active hydrogen-containing resin and diluent. 0.01% of dibutyltin dilaurate was added as a drying agent based on the total mass. The test was conducted using a Guangzhou BGD261 linear drying recorder, referring to GB / T 1728 and GB / T1730.

[0071] (6) Storage stability: The prepared polyisocyanate composition was sealed in a glass bottle and stored at room temperature (25°C) for 12 months. The viscosity and turbidity were recorded.

[0072] The following are specific embodiments and comparative examples:

[0073]

Example 1

[0074] Under an inert gas atmosphere, 950g of 1,3-cyclohexyldimethylene diisocyanate (1,3-HXDI) and 50g of 1,4-cyclohexyldimethylene diisocyanate (1,4-HXDI) were first added to a reaction vessel and thoroughly mixed. 0.63g of distilled water was added, and the mixture was then heated to 120℃ for biuretization pretreatment for 2 hours. The temperature was then lowered to 80℃, and approximately 0.62g of tetrabutylammonium hydroxide catalyst was added to initiate a trimerization reaction. Upon completion of trimerization, 0.56g of dioctyl phosphate was added to terminate the reaction, yielding an isocyanate mixture solution. Unreacted monomers were further removed by thin-film evaporation distillation. The temperature of the thin-film evaporator was controlled at 150℃ and the vacuum degree at 25 Pa. The distilled composition was diluted with ethyl acetate to a mass concentration of 75%, yielding polyisocyanate composition #1.

[0075]

Examples 2-6

[0076] The polyisocyanate compositions of Examples 2-6 were prepared using essentially the same method as in Example 1, with the only difference being the process conditions listed in Table 1. The compositions prepared in each example are designated as polyisocyanate compositions 2#-6#.

[0077] Table 1 shows the different process conditions in each embodiment.

[0078]

[0079] Comparative Example 1

[0080] Polyisocyanates prepared from pure 1,3-HXDI are compared with those in Example 5.

[0081] Under an inert gas atmosphere, 1000 g of 1,3-cyclohexyldimethylene diisocyanate (1,3-HXDI) was added to a reaction vessel, along with 0.28 g of distilled water. The mixture was then heated to 130 °C for biuretization pretreatment for 1 h, followed by cooling to 100 °C. Approximately 0.62 g of tetrabutylammonium hydroxide catalyst was added to initiate a trimerization reaction. Upon completion of trimerization, 0.56 g of dioctyl phosphate was added to terminate the reaction, yielding an isocyanate mixture solution. Unreacted monomers were further removed by thin-film distillation. The temperature of the thin-film evaporator was controlled at 150 °C and the vacuum degree at 25 Pa. The distilled composition was diluted with ethyl acetate to a mass concentration of 75%, yielding polyisocyanate composition 7#.

[0082] Comparative Example 2

[0083] Polyisocyanates prepared from pure 1,4-HXDI are compared with those in Example 4.

[0084] Under an inert gas atmosphere, 1000 g of 1,4-cyclohexyldimethylene diisocyanate (1,4-HXDI) was added to a reaction vessel, along with 0.44 g of distilled water. The mixture was then heated to 160 °C for biuretization pretreatment for 2 h, followed by cooling to 80 °C. Approximately 0.62 g of tetrabutylammonium hydroxide catalyst was added to initiate a trimerization reaction. Upon completion of trimerization, 0.32 g of dibutyl phosphate was added to terminate the reaction, yielding an isocyanate mixture solution. Unreacted monomers were further removed by thin-film evaporation distillation. The temperature of the thin-film evaporator was controlled at 140 °C and the vacuum degree at 30 Pa. The distilled composition was diluted with ethyl acetate to a mass concentration of 75%, yielding polyisocyanate composition 8#.

[0085] Comparative Example 3

[0086] Compared with Example 4, the composition of the raw materials is not within the scope of this invention.

[0087] Under an inert gas atmosphere, 900g of 1,3-cyclohexyldimethylene diisocyanate (1,3-HXDI) and 100g of 1,4-cyclohexyldimethylene diisocyanate (1,4-HXDI) were first added to a reaction vessel and thoroughly mixed. 0.44g of distilled water was added, and the mixture was then heated to 160℃ for biuretization pretreatment for 2 hours. The temperature was then lowered to 80℃, and approximately 0.62g of tetrabutylammonium hydroxide catalyst was added to initiate a trimerization reaction. Upon completion of trimerization, 0.32g of dibutyl phosphate was added to terminate the reaction, yielding an isocyanate mixture solution. Unreacted monomers were further removed by thin-film evaporation distillation. The temperature of the thin-film evaporator was controlled at 160℃ and the vacuum degree at 10 Pa. The distilled composition was diluted with ethyl acetate to a mass concentration of 75%, yielding polyisocyanate composition 9#.

[0088] Comparative Example 4

[0089] Compared with Example 4, the difference lies in the change of the amount of distilled water.

[0090] Under an inert gas atmosphere, 940 g of 1,3-cyclohexyldimethylene diisocyanate (1,3-HXDI) and 30 g of 1,4-cyclohexyldimethylene diisocyanate (1,4-HXDI) were first added to a reaction vessel and thoroughly mixed. 0.98 g of distilled water was added, and the mixture was then heated to 160 °C for biuretization pretreatment for 2 h. The temperature was then lowered to 80 °C, and approximately 0.62 g of tetrabutylammonium hydroxide solution was added to initiate a trimerization reaction. Upon completion of the trimerization cyclization, 0.32 g of dibutyl phosphate was added to terminate the reaction, yielding an isocyanate mixture solution. Unreacted monomers were further removed by thin-film evaporation distillation. The temperature of the thin-film evaporator was controlled at 170 °C and the vacuum degree at 50 Pa. The distilled composition was diluted with ethyl acetate to a mass concentration of 75%, yielding polyisocyanate composition 10#.

[0091] The initial viscosity, turbidity, Tg, and drying performance of the polyisocyanate compositions prepared in each example and comparative example were analyzed. The results are shown in Table 2.

[0092] Table 2 Initial state analysis results of polyisocyanate compositions

[0093]

[0094] Storage stability tests were conducted on the polyisocyanate compositions prepared in the above examples and comparative examples. Changes in viscosity, turbidity, and appearance were recorded after 12 months of storage at room temperature (25°C). The analytical results are shown in Table 3.

[0095] Table 3. Analysis results of polyisocyanate compositions after 12 months of storage at room temperature.

[0096]

[0097] As shown in Tables 2 and 3, the polyisocyanate compositions prepared in Examples 1-6 exhibit superior storage stability and good drying properties; while the polyisocyanate compositions prepared in Comparative Examples 1-4 show obvious deficiencies in storage stability or drying properties, making it difficult to meet practical needs.

[0098] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A storage-stable polyisocyanate composition based on cyclohexyldimethylene diisocyanate, characterized in that, The composition is prepared from cyclohexyldimethylene diisocyanate monomer, satisfying (1) the following compositional relationship of its monomer raw materials: (a) The content of 1,3-cyclohexyldimethylene diisocyanate is 95.0%-99.9%. (b) The content of 1,4-cyclohexyldimethylene diisocyanate is 0.1%-5.0%; (2) Based on the total mass of the polyisocyanate composition, the composition satisfies that the sum of the content of the dimer formed by cyclohexyldimethylene diisocyanate and the biuret content is between 0.2% and 4.0%; The preparation method of the composition includes the following steps: adding cyclohexyldimethylene diisocyanate to a reaction vessel, adding distilled water first under an inert gas atmosphere, then raising the temperature for biuretization pretreatment, then cooling down, and then partially cyclizing cyclohexyldimethylene diisocyanate in the presence of a trimerizing catalyst, terminating the trimerizing catalyst with a terminator at the end of the cyclization, and finally removing unreacted isocyanate monomers. Of which, the amount of distilled water used is 0.005%-0.1% based on the total amount of cyclohexyl dimethylene diisocyanate.

2. The polyisocyanate composition according to claim 1, characterized in that, The glass transition temperature of the composition is 20-60℃.

3. The polyisocyanate composition according to claim 1 or 2, characterized in that, The composition is a modified composition obtained by polymerization or modification of cyclohexyldimethylene diisocyanate.

4. The polyisocyanate composition according to claim 3, characterized in that, The composition contains one or more of (a) isocyanurate group, (b) diuret group, (c) biuret group, (d) carbamate group, and (e) urethane group.

5. A method for preparing a polyisocyanate composition, wherein the composition is the polyisocyanate composition according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: adding cyclohexyldimethylene diisocyanate to a reaction vessel, adding distilled water first under an inert gas atmosphere, then raising the temperature for biuretization pretreatment, then cooling down, and then partially cyclizing cyclohexyldimethylene diisocyanate in the presence of a trimerizing catalyst. At the end of the cyclization, a terminator is used to terminate the trimerizing catalyst, and finally unreacted isocyanate monomers are removed.

6. The preparation method according to claim 5, characterized in that, The temperature is raised to 120-160℃, the biuretization pretreatment time is 1-4 hours, and then the temperature is lowered to 40-100℃.

7. A polyurethane resin, comprising the polyisocyanate composition according to any one of claims 1-4, or the polyisocyanate composition prepared by the preparation method described in claim 5 or 6, characterized in that, The polyurethane resin is formed by reacting the polyisocyanate composition of the cyclohexyldimethylene diisocyanate with a substance containing active hydrogen groups.

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