Wood lacquer coating composition

Abstract

The invention provides a wood lacquer coating composition, and relates to the technical field of wood lacquer. The wood lacquer coating composition consists of a component A and a component B according to a molar equivalence ratio of 1: (1-1.1), the component A comprises the following raw material components: composite aspartic ester resin consisting of first aspartic ester resin and second aspartic ester resin; the weight of the second aspartic ester resin accounts for 10-40% of the weight of the composite aspartic ester resin; the first aspartic acid ester resin is bifunctional aspartic acid ester, the second aspartic acid ester resin is monofunctional aspartic acid ester, and the first aspartic acid ester resin and the second aspartic acid ester resin are both low in viscosity; and the component B is an isocyanate curing agent. A coating formed by curing the wood lacquer coating composition has good water resistance, heat resistance, aging resistance, smudginess resistance, hand feeling and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of wood paint and relates to a wood paint coating composition. Background Art

[0002] Solid wood has natural texture and is deeply loved by consumers. In order to prevent the surface of solid wood furniture from being worn and dirty, a layer of transparent protective paint is usually applied on the surface of solid wood. Wood wax oil is one of them. It can penetrate into the interior of the wood, give deep moisturizing and maintenance to the wood, and the surface has an open texture effect, and is closely combined with wood fibers, enhancing the surface hardness, waterproof and anti-fouling, wear and rub resistance, providing excellent maintenance and decorative effects for the wood. However, wood wax oil also has the problems of insufficient water resistance (24h water resistance does not reach level 1, generally around level 3), poor aging resistance (obvious yellowing after aging for 1000h), and poor pollution resistance (fouling resistance is generally level 5).

[0003] Chinese patent CN111635498A discloses a modified polyurea and its application as wood coating, wherein the modified polyurea is obtained by reacting monofunctional isocyanate with polyaspartic acid resin. However, in this technology, aspartic acid resin with high viscosity is still used, such as F420, F520, F530 and other resins of Feiyang Junyan Company, and the obtained coating composition has high viscosity. In addition, the use of monofunctional isocyanate as a curing agent will result in insufficient crosslinking degree of the polyurea coating.

[0004] Therefore, it is necessary to develop a wood paint that can replace wood wax oil to play a decorative and protective role on the surface of solid wood, and has better water resistance, aging resistance, pollution resistance and other properties. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a wood paint coating composition.

[0006] The technical solution of the present invention is as follows:

[0007] A wood coating composition, comprising component A and component B in a molar equivalent ratio of 1:1-1.1;

[0008] The raw material components of the A component include a composite aspartic acid ester resin composed of a first aspartic acid ester resin and a second aspartic acid ester resin;

[0009] The weight proportion of the second aspartic acid ester resin in the composite aspartic acid ester resin is 10-40%;

[0010] The first aspartic acid ester resin is a difunctional aspartic acid ester having a viscosity of no more than 500 mPa.s at 25°C;

[0011] The second aspartic acid ester resin is a monofunctional aspartic acid ester with a viscosity of no more than 50 mPa.s at 25°C;

[0012] The B component is an isocyanate curing agent.

[0013] Preferably, the first aspartic acid ester resin and the second aspartic acid ester resin each contain only one cycloalkyl subunit in their molecular structure.

[0014] More preferably, the structure of the first aspartic acid ester resin is as shown in the following formula (I):

[0015]

[0016] Wherein, R1 is selected from C5-C7 cycloalkylene or substituted C6-C10 cycloalkylene, and R2 and R3 are independently selected from C1-C4 alkyl.

[0017] More preferably, the structure of the second aspartic acid ester resin is as shown in the following formula (II):

[0018]

[0019] Wherein, R4 is selected from C5-C7 cycloalkyl, substituted C6-C10 cycloalkyl or trialkoxysilylpropyl, and R5 and R6 are independently selected from C1-C4 alkyl.

[0020] Preferably, the weight proportion of the second aspartic acid ester resin in the composite aspartic acid ester resin is higher than 10% and not more than 35%.

[0021] Preferably, the viscosity of the isocyanate curing agent at 25° C. does not exceed 500 mPa.s.

[0022] More preferably, the isocyanate curing agent is selected from one or a combination of two or more of Asahi Kasei TUL-100, Wanhua HT-300 and Covestro N3400.

[0023] Preferably, the raw material components of component A further include one or a combination of two of an organic solvent and carnauba wax.

[0024] More preferably, the weight proportion of the organic solvent and the carnauba wax alone in the component A does not exceed 10%.

[0025] More preferably, the weight proportion of the composite aspartic acid ester resin in the component A is not less than 70%.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention uses a low-viscosity first aspartic acid ester resin (difunctional aspartic acid ester resin) and a second aspartic acid ester resin (monofunctional aspartic acid ester resin) for wood paint coatings. The wood paint coating composition has low viscosity and does not need to be diluted with an organic solvent, thereby achieving solvent-free or ultra-high solid content. A hand-rubbing process can be used, and the permeability is good, so that the wood paint coating can penetrate into the interior of the wood. The cured wood paint coating has good properties such as water resistance, heat resistance, aging resistance, and stain resistance.

[0028] (2) In the present invention, the weight ratio of the first aspartic acid resin and the second aspartic acid resin is within a suitable range, and the obtained wood paint coating has a good surface feel without adding a feel aid. The aspartic acid resin has a long operating time and cures quickly. After the coating is cured, the wood surface presents a semi-open texture effect, the wood texture is clear, the texture is natural, the wood is oily, the color is natural, and the feel is silky. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0030] In order to obtain a wood coating composition having good permeability to solid wood, suitable for hand-rubbing coating process, and having good water resistance, stain resistance, aging resistance and other properties after curing, the present invention provides a wood coating composition, which is composed of component A and component B in a molar equivalent ratio of 1:1-1.1;

[0031] The raw material components of component A include a composite aspartic acid ester resin composed of a first aspartic acid ester resin and a second aspartic acid ester resin;

[0032] The second aspartic acid ester resin accounts for 10-40% by weight in the composite aspartic acid ester resin;

[0033] The first aspartic acid ester resin is a difunctional aspartic acid ester with a viscosity of no more than 500 mPa.s at 25°C;

[0034] The second aspartic acid ester resin is a monofunctional aspartic acid ester with a viscosity of no more than 50 mPa.s at 25°C;

[0035] Component B is an isocyanate curing agent.

[0036] In the present invention, functionality refers to the secondary amine group in aspartic acid ester. Component A in the present invention contains two aspartic acid ester resins, the first aspartic acid ester resin is bifunctional and contains two secondary amine groups, and the second aspartic acid ester resin is monofunctional and contains one secondary amine group, both of which have a lower viscosity, so the wood paint coating composition can achieve a lower viscosity, and can have a higher permeability to solid wood without the need for additional additives. In addition, since the monofunctional aspartic acid ester can play a good dilution role, the operable time of the wood paint coating composition can be extended, which is more conducive to the permeability of the coating composition to solid wood, and does not affect the curability of the wood paint coating composition, and the coating has good water resistance, stain resistance, aging resistance and other properties.

[0037] If the content of the second aspartic acid ester resin is too high, the curing performance of the wood coating composition may be affected, and the obtained coating may have insufficient stain resistance and water resistance due to insufficient crosslinking. In the present invention, the weight proportion of the second aspartic acid ester resin in the composite aspartic acid ester resin can be any value of 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc., without special restrictions.

[0038] In a preferred embodiment of the present invention, the first aspartic acid resin and the second aspartic acid resin each contain only one cycloalkylene subunit in their molecular structure. Conventional aspartic acid resins, such as F420 and F520 resins of Feiyang Junyan Company, are obtained by Michael addition reaction of 4,4-diaminodicyclohexylmethane or 3,3'-dimethyl-4,4-diaminodicyclohexylmethane with diethyl maleate, and contain 2 cycloalkylene subunits in their molecular structure, and therefore have a higher viscosity. In the present invention, the first aspartic acid resin and the second aspartic acid resin each have only one cycloalkylene subunit in their molecular structure, and have a lower viscosity, especially the viscosity (25°C) of the second aspartic acid resin does not exceed 50mPa.s, and the obtained composite aspartic acid resin has a lower viscosity and a higher permeability, and is suitable for surface coating of solid wood, and is easier to penetrate into the texture of wood, and the cyclohexylene subunit has a certain steric hindrance effect on the adjacent secondary amine group, and can also further extend the operable time of the wood coating composition.

[0039] In a more preferred embodiment of the present invention, the structure of the first aspartic acid ester resin is shown in the following formula (I):

[0040]

[0041] Wherein, R1 is selected from C5-C7 cycloalkylene or substituted C6-C10 cycloalkylene, and R2 and R3 are independently selected from C1-C4 alkyl.

[0042] In the present invention, the first aspartic acid ester resin can still be obtained by Michael addition reaction, and is obtained by Michael addition reaction of cycloalkylenediamine NH2R1NH2 and maleic acid ester. The reaction operation is well known to those skilled in the art. Taking 1,4-cyclohexanediamine as an example, the reaction operation can be as follows: add 1 molar portion of 1,4-cyclohexanediamine to a reaction container, gradually add 2-2.5 molar portions of diethyl maleate under stirring, heat to 70-100°C and react for 24-120h, then heat and reduce pressure to remove unreacted raw materials, and obtain the first aspartic acid ester resin, and the viscosity (25°C) is measured to be 290-350mPa.s.

[0043] For R1 in the above formula (I), the corresponding cycloalkylenediamine is more preferably 1,4-cyclohexanediamine, 2-methyl-1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1-methyl-2,4-cyclohexanediamine, etc., in view of the availability of raw materials.

[0044] In a more preferred embodiment of the present invention, the structure of the second aspartic acid ester resin is shown in the following formula (II):

[0045]

[0046] Wherein, R4 is selected from C5-C7 cycloalkyl, substituted C6-C10 cycloalkyl or trialkoxysilylpropyl, and R5 and R6 are independently selected from C1-C4 alkyl.

[0047] In the present invention, the second aspartic acid ester resin can still be obtained by Michael addition reaction, and is obtained by Michael addition reaction of cycloalkyl monoamine R4NH2 or amino-containing silane coupling agent with maleic acid ester. The reaction operation is well known to those skilled in the art. Taking cyclohexylamine as an example, the reaction operation can be as follows: add 1 mole of cyclohexylamine to a reaction container, gradually add 0.8-1.2 mole of diethyl maleate under stirring, heat to 60-80°C and react for 24-120h, then heat and reduce pressure to remove unreacted raw materials to obtain the second aspartic acid ester resin, and the viscosity (25°C) is measured to be 10-12mPa.s.

[0048] For R4 in the above formula (II), the corresponding cycloalkylamine is more preferably cyclohexylamine, 2-methylcyclohexylamine, 3-methylcyclohexylamine, 4-methylcyclohexylamine, etc., in view of the ease of obtaining the raw materials.

[0049] In a preferred embodiment of the present invention, the weight proportion of the second aspartic acid ester resin in the composite aspartic acid ester resin is higher than 10% and does not exceed 35%. By adopting the above technical scheme, the content of the second aspartic acid ester resin is within a certain range, and the coating composition has good water resistance, dirt resistance, aging resistance and other properties after curing, and also has a fuller feel, which occurs without adding a feel aid. For example, the weight proportion of the second aspartic acid ester resin in the composite aspartic acid ester resin can be any value of 10.5%, 12%, 15%, 17%, 18%, 20%, 22%, 25%, 27%, 29%, 30%, 32%, 35%, etc., without special restrictions.

[0050] If the viscosity of the isocyanate curing agent is too high, the viscosity of the coating composition will be significantly increased, which is not conducive to the hand-rubbing process and the penetration of the coating composition into solid wood. In a preferred embodiment of the present invention, the viscosity of the isocyanate curing agent at 25°C does not exceed 500mPa.s. In a more preferred embodiment, the isocyanate curing agent is selected from one or a combination of two or more of Asahi Kasei TUL-100, Wanhua HT-300 and Covestro N3400. The viscosity of Asahi Kasei TUL-100 at 25°C is about 300mPa.s, the viscosity of Wanhua HT-300 at 25°C is about 400mPa.s, and the viscosity of Covestro N3400 at 25°C is about 200mPa.s. These curing agents have lower viscosity and better curing performance, and can be directly obtained from the market, which is convenient to obtain.

[0051] In a preferred embodiment of the present invention, the raw material components of component A also include a combination of one or two of an organic solvent and carnauba wax. The organic solvent can be added as needed, for example, to further reduce the viscosity of the coating composition and / or to further improve the penetration into solid wood, but the added weight is preferably not more than 10% of the weight of component A. The organic solvent is not particularly limited, and can be butyl acetate, ethyl acetate, acetone, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, etc. Carnauba wax is solid at room temperature and can be dissolved in component A of the present invention, thereby improving the permeability into solid wood. The added weight of carnauba wax is preferably not more than 10% of the weight of component A, and for example, can be any value of 2%, 5%, 8%, 10%, etc., without particular limitation.

[0052] In a more preferred embodiment of the present invention, the weight proportion of the composite aspartic acid ester resin in component A is not less than 70%. If the weight proportion of the composite aspartic acid ester resin in component A is insufficient, the performance of the coating may be affected. For example, the weight proportion of the composite aspartic acid ester resin in component A can be 70%, 75%, 80%, 85%, 90%, 95%, 100%, etc. More preferably, the weight proportion of the composite aspartic acid ester resin in component A is not less than 85%.

[0053] The preparation method of the wood coating composition of the present invention is not particularly limited, and can be as follows: uniformly mix the raw material components of component A and then uniformly mix with component B. The wood coating composition can be applied on solid wood by hand rubbing.

[0054] The technical solution of the present invention is further described and illustrated according to various embodiments below. Unless otherwise specified, the parts described in the following embodiments are parts by weight.

[0055] Preparation Example 1-3 Preparation of the first aspartic acid ester resin

[0056] Preparation Example 1

[0057] 1 mol of 1,4-cyclohexanediamine and 2.4 mol of diethyl maleate were added to a reaction container, the temperature was raised to 100°C and the reaction was carried out for 48 hours, the temperature was raised to 150°C and the pressure was reduced to below -0.099 MPa to remove the unreacted raw materials, and the first aspartic acid ester resin was obtained, and the viscosity (25°C) was 310 mPa.s.

[0058] Preparation Example 2

[0059] 1 mol of 1,3-cyclohexanediamine and 2.1 mol of diisobutyl maleate were added to a reaction container, the temperature was raised to 100°C for reaction for 60 hours, the temperature was raised to 160°C, the pressure was reduced to below -0.099 MPa to remove unreacted raw materials, and the first aspartic acid ester resin was obtained with a viscosity (25°C) of 450 mPa.s.

[0060] Preparation Example 3

[0061] 1 mol of 1,3-cyclopentanediamine and 2.2 mol of diethyl maleate were added to a reaction container, the temperature was raised to 100°C for reaction for 48 hours, the temperature was raised to 150°C, the pressure was reduced to below -0.099 MPa to remove unreacted raw materials, and the first aspartic acid ester resin was obtained with a viscosity (25°C) of 270 mPa.s.

[0062] Preparation Example 4-5 Preparation of Second Aspartic Acid Ester Resin

[0063] Preparation Example 4

[0064] 1 mol of cyclohexylamine was added to the reaction container, 1.2 mol of diethyl maleate was added dropwise, the temperature was raised to 100°C for reaction for 24 hours, and the pressure was reduced to below -0.099 MPa to remove the unreacted raw materials to obtain the second day aspartic acid ester resin with a viscosity (25°C) of 11 mPa.s.

[0065] Preparation Example 5

[0066] 1 mol of 2-methylcyclohexylamine was added to the reaction container, 1.1 mol of diethyl maleate was added dropwise, the temperature was raised to 100°C for reaction for 36 hours, and the pressure was reduced to below -0.099 MPa to remove the unreacted raw materials to obtain the second day aspartic acid ester resin with a viscosity (25°C) of 18 mPa.s.

[0067] Example 1

[0068] Component A is composed of the first aspartic acid ester resin of Preparation Example 1 and the second aspartic acid ester resin of Preparation Example 4 in a weight ratio of 9:1.

[0069] Component B is Asahi Kasei TUL-100 curing agent.

[0070] The wood coating composition consists of component A and component B in a molar equivalent ratio of 1:1.05, and weighs 1 kg.

[0071] Example 2

[0072] The difference between this embodiment and embodiment 1 is that in embodiment 1, the weight ratio of the first aspartic acid ester resin and the second aspartic acid ester resin is adjusted from 9:1 to 8:2. The other steps remain unchanged.

[0073] Example 3

[0074] The difference between this embodiment and embodiment 1 is that in embodiment 1, the weight ratio of the first aspartic acid ester resin and the second aspartic acid ester resin is adjusted from 9:1 to 7:3. The other steps remain unchanged.

[0075] Example 4

[0076] The difference between this embodiment and embodiment 1 is that in embodiment 1, the weight ratio of the first aspartic acid ester resin and the second aspartic acid ester resin is adjusted from 9:1 to 6.5:3.5. The other steps remain unchanged.

[0077] Example 5

[0078] The difference between this embodiment and embodiment 1 is that in embodiment 1, the weight ratio of the first aspartic acid ester resin and the second aspartic acid ester resin is adjusted from 9:1 to 6:4. The other steps remain unchanged.

[0079] Comparative Example 1

[0080] The difference between this comparative example and Example 1 is that in Example 1, the second aspartic acid ester resin is replaced by an equal weight of the first aspartic acid ester resin, and the other steps remain unchanged.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 1 is that in Example 1, the weight ratio of the first aspartic acid ester resin and the second aspartic acid ester resin is adjusted from 9:1 to 5.5:4.5. The other steps remain unchanged.

[0083] Comparative Example 3

[0084] The difference between this comparative example and Example 1 is that in Example 1, the weight ratio of the first aspartic acid ester resin and the second aspartic acid ester resin is adjusted from 9:1 to 9.5:0.5. The other steps remain unchanged.

[0085] Comparative Example 4

[0086] The difference between this comparative example and comparative example 1 is that in comparative example 1, a hand feeling agent is added to component A. 82W, the weight of the feel agent is 0.5% of the weight of component A. The rest of the steps remain unchanged.

[0087] Comparative Example 5

[0088] The difference between this comparative example and Example 2 is that in Example 2, the first aspartic acid ester resin is replaced by an equal weight of F420 resin from Feiyang Junyan Co., Ltd. The remaining steps remain unchanged.

[0089] Example 6

[0090] Component A is composed of the first aspartic acid ester resin of Preparation Example 2 and the second aspartic acid ester resin of Preparation Example 5 in a weight ratio of 7:3.

[0091] Component B is Covestro N3400 curing agent.

[0092] The wood coating composition consists of component A and component B in a molar equivalent ratio of 1:1.05, and weighs 1 kg.

[0093] Example 7

[0094] Component A is composed of the first aspartic acid ester resin of Preparation Example 3 and the second aspartic acid ester resin of Preparation Example 4 in a weight ratio of 8:2.

[0095] Component B is Covestro N3400 curing agent.

[0096] The wood coating composition consists of component A and component B in a molar equivalent ratio of 1:1.05, and weighs 1 kg.

[0097] Example 8

[0098] The difference between this embodiment and embodiment 7 is that in embodiment 7, 5% carnauba wax is added to component A. The other steps remain unchanged.

[0099] Example 9

[0100] The difference between this embodiment and embodiment 7 is that in embodiment 7, carnauba wax accounting for 10% by weight of component A is added to component A. The other steps remain unchanged.

[0101] Performance Testing

[0102] The properties of the wood coating compositions of Examples 1-9 and Comparative Examples 1-5 are shown in Table 1 below.

[0103] Color: Tested according to the method of GB / T 1721-2008.

[0104] Viscosity: Tested by Tu-4S cup method according to GB / T 1723-1193.

[0105] Applicable period: Tested according to the method of GB / T 31416-2015.

[0106] Surface drying time and thorough drying time: tested according to the method of GB / T 1728-2020.

[0107] Table 1

[0108]

[0109]

[0110] It can be seen from the data in Table 1 above that the wood paint coating composition of the present invention adopts a combination of the first aspartic acid ester resin and the second aspartic acid ester resin as the main component of component A, has a lower viscosity and a suitable application period, surface drying time, etc., is suitable as a wood paint for solid wood and adopts a hand-rubbing process.

[0111] The wood coating compositions of Examples 1-9 and Comparative Examples 1-5 were applied to the surface of solid wood by hand rubbing and cured to form a shape. It can be observed that the coating compositions penetrated into the texture of the wood.

[0112] Water resistance: Tested according to the method of GB / T 17657-2022. After 24 tests, it is considered passed if the water resistance does not exceed level 2.

[0113] Dry heat resistance: Tested according to the method of GB / T4893.3-2020, 70℃×15min, no change is required.

[0114] Aging resistance: tested according to GB / T 1865-2009 method, 340nm wavelength, average irradiance 0.51W / m 2 After 1000 hours of irradiation, the degree of gloss loss is tested according to the standard of GB / T1766-2008, and it is required not to exceed level 3.

[0115] Stain resistance: tested according to the method of GB / T 17657-2022, and the test result is considered passed if it does not exceed level 2.

[0116] Feel: Five trained volunteers gently rubbed the surface of the coating to be tested with the back of their hands to evaluate the fullness and smoothness and give scores. The lowest score was 1 for the coating of Comparative Example 1, and the highest score was 5 for the coating of Comparative Example 4. The highest and lowest scores of each coating to be tested were removed, and the remaining 3 scores were averaged.

[0117] The results are shown in Table 2 below.

[0118] Table 2

[0119]

[0120] It can be seen from the data in Table 2 that the wood coating composition of the present invention has good water resistance, heat resistance and stain resistance after curing, and has a good hand feel.

[0121] As described above, the basic principles, main features and advantages of the present invention are shown and described. Those skilled in the art should understand that the present invention is not limited by the above embodiments, which are only preferred embodiments of the present invention and cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the scope of the present invention and the content of the specification should still be within the scope of the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents.

Claims

1. A wood coating composition, characterized in that: It is composed of component A and component B in a molar equivalent ratio of 1:1-1.1; The raw material components of the A component include a composite aspartic acid ester resin composed of a first aspartic acid ester resin and a second aspartic acid ester resin; The weight proportion of the second aspartic acid ester resin in the composite aspartic acid ester resin is 10-40%; The first aspartic acid ester resin is a difunctional aspartic acid ester having a viscosity of no more than 500 mPa.s at 25°C; The second aspartic acid ester resin is a monofunctional aspartic acid ester with a viscosity of no more than 50 mPa.s at 25°C; The B component is an isocyanate curing agent.

2. The wood coating composition according to claim 1, characterized in that The first aspartic acid ester resin and the second aspartic acid ester resin each contain only one cycloalkyl subunit in their molecular structure.

3. The wood coating composition according to claim 2, characterized in that: The structure of the first aspartic acid ester resin is shown in the following formula (I): Wherein, R1 is selected from C5-C7 cycloalkylene or substituted C6-C10 cycloalkylene, and R2 and R3 are independently selected from C1-C4 alkyl.

4. The wood coating composition according to claim 2, characterized in that: The structure of the second aspartic acid ester resin is shown in the following formula (II): Wherein, R4 is selected from C5-C7 cycloalkyl, substituted C6-C10 cycloalkyl or trialkoxysilylpropyl, and R5 and R6 are independently selected from C1-C4 alkyl.

5. The wood coating composition according to claim 1, characterized in that: The weight proportion of the second aspartic acid ester resin in the composite aspartic acid ester resin is higher than 10% and not more than 35%.

6. The wood coating composition according to claim 1, characterized in that: The viscosity of the isocyanate curing agent at 25° C. does not exceed 500 mPa.s.

7. The wood coating composition according to claim 6, characterized in that: The isocyanate curing agent is selected from one or a combination of two or more of Asahi Kasei TUL-100, Wanhua HT-300 and Covestro N3400.

8. The wood coating composition according to claim 1, characterized in that: The raw material components of the A component further include one or a combination of two of an organic solvent and carnauba wax.

9. The wood coating composition according to claim 8, characterized in that: The weight proportion of the organic solvent and the carnauba wax alone in the component A does not exceed 10%.

10. The wood coating composition according to claim 8, characterized in that: The weight proportion of the composite aspartic acid ester resin in the component A is not less than 70%.

Images