Hyposensitization radix asparagi resin and preparation method thereof

Abstract

The invention provides low-sensitization radix asparagi resin and a preparation method thereof, and relates to the technical field of radix asparagi resin. The low-sensitization asparagus resin comprises secondary amino resin with the structure shown in the specification and diethyl fumarate and / or diethyl maleate which account for not more than 0.5% of the weight of the asparagus resin # imgabs0 #, X is selected from a divalent organic structure which is left after two primary amino groups are removed from a diamine compound and is inert with an isocyanate group at the temperature of 100 DEG C and has the average molecular weight of 50-5000, and X is selected from a divalent organic structure with the average molecular weight of 50-5000 and a divalent organic structure with the average molecular weight of 50-5000 and a divalent organic structure with the average molecular weight of 50-5000 after two primary amino groups are removed from the diamine compound. Et represents ethyl, R1 is selected from C2-C8 alkyl groups, and the molar percentage of the C4-C8 alkyl groups in R1 is not less than 10%. The radix asparagi resin disclosed by the invention has no great change in curing performance, but basically has no sensitization.

Description

Technical Field

[0001] The invention belongs to the technical field of asparagus resins and relates to a low-allergenic asparagus resin and a preparation method thereof. Background Art

[0002] Asparagine resin is usually prepared by Michael addition reaction of dialkyl maleate and organic polyamine, and the most commonly used dialkyl maleate is diethyl maleate. In order to promote the more complete reaction of organic polyamine and avoid the influence of residual primary amine groups on the curing operation time of asparagine resin, excessive diethyl maleate is usually added, but diethyl maleate will gradually be converted into diethyl fumarate with lower reaction activity under the reaction conditions of synthesizing asparagine resin, resulting in a slow reaction rate, an increase in residual diethyl maleate and diethyl fumarate, and diethyl maleate and diethyl fumarate have greater irritation to human skin, bronchus, throat mucosa, etc. According to the above-mentioned method for preparing asparagine resin, the content of free diethyl maleate and / or diethyl fumarate in asparagine resin can reach 2wt% or even higher, which can produce stronger sensitization to human skin, bronchus, throat mucosa, etc. The boiling point of diethyl maleate at 1 atmosphere is about 220°C, and conventional vacuum distillation methods are difficult to reduce the content of diethyl maleate in asparagine resin to 2wt% or less. In order to reduce the free diethyl maleate and / or diethyl fumarate in asparagine resin, the industry generally adopts a short-range molecular distillation method, which can reduce the content of free diethyl maleate and / or diethyl fumarate to 0.5wt%. When the content of diethyl maleate and / or diethyl fumarate in asparagine resin does not exceed 0.5wt%, the irritation and sensitization to human body are very low. However, the short-range molecular distillation method has the problems of expensive equipment, increased production cycle, increased cost, etc., which greatly restricts the application of asparagine resin and the development of the industry.

[0003] Therefore, the industry urgently needs to improve the current process method to reduce equipment investment, improve production efficiency, and thereby reduce the cost of asparagus resin, while controlling the content of diethyl maleate and / or diethyl fumarate in asparagus resin to no more than 0.5wt% to avoid sensitization to the human body. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a low-allergenic asparagine resin and a preparation method thereof.

[0005] The technical solution of the present invention is as follows:

[0006] A low-allergenic asparagine resin comprises a secondary amino resin having a structure as shown in the following formula (1) and diethyl fumarate and / or diethyl maleate in an amount not exceeding 0.5% by weight of the asparagine resin.

[0007]

[0008] Wherein, X is selected from a divalent organic structure with an average molecular weight of 50-5000 which is inert to react with isocyanate groups at 100° C. and which remains after two primary amino groups are removed from a diamine compound; Et represents an ethyl group; R1 is selected from a C2-C8 alkyl group; and the molar percentage of the C4-C8 alkyl group in R1 is not less than 10%.

[0009] Preferably, the molar percentage of C4-C8 alkyl in R1 is not less than 20%.

[0010] Preferably, the sum of the weight percentages of the diethyl fumarate and the diethyl maleate in the asparagine resin does not exceed 0.5%.

[0011] Preferably, the diamine compound is selected from one or a combination of two or more of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 1-methyl-2,4-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, o-diaminomethylcyclopentane and polyetheramine.

[0012] A method for preparing a low-allergenic asparagine resin according to any one of the above embodiments, comprising: slowly dropping the diethyl maleate into the diamine compound in a molar ratio of 1:0.5-0.95 under stirring, heating the mixture to 40-70°C for reaction until the sum of the weight percentages of diethyl maleate and diethyl fumarate does not exceed 0.5%, adding a maleate ester as shown in the structure of the following formula (2), adjusting the temperature to 60-100°C for reaction for 24-96h, and then maintaining the temperature at 80-100°C for vacuum removal of low-boiling substances, thereby obtaining the low-allergenic asparagine resin;

[0013] R2OCOCH=CHCOOR2 (2)

[0014] Wherein, R2 is selected from C4-C8 alkyl.

[0015] Preferably, R2 is selected from C4 alkyl.

[0016] Preferably, the diamine compound is selected from one or a combination of two or more of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 1-methyl-2,4-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, o-diaminomethylcyclopentane and polyetheramine.

[0017] Preferably, the molar ratio of the primary amino group in the diamine compound to the diethyl maleate is 1:0.5-0.9.

[0018] Preferably, the molar ratio of the primary amino group in the diamine compound to the maleate is 1:0.1-0.6.

[0019] Preferably, the ratio of the molar number of the primary amino group in the diamine compound to the sum of the molar numbers of the diethyl maleate and the maleate is 1:1-1.1.

[0020] The beneficial effects of the present invention are:

[0021] (1) In the asparagine resin of the present invention, the ester structure of the secondary amino resin contains an alkyl group of C4 or above. By controlling the content of the alkyl group of C4 or above, the weight percentage of diethyl fumarate and / or diethyl maleate can be controlled to not more than 0.5% without affecting the performance of the asparagine resin, thereby avoiding sensitization to the human body.

[0022] (2) In the preparation of the secondary amino resin of the present invention, the reaction of the diamine compound with diethyl maleate can be carried out at a relatively low temperature by using an excess diamine compound, thereby minimizing the conversion of diethyl maleate into diethyl fumarate, effectively increasing the reaction rate and promoting the complete reaction of diethyl maleate / diethyl fumarate. Moreover, the excess diamine compound can be reacted by adding a maleate having a structure shown in the above formula (2), and a small amount of maleate that has not reacted completely will not cause allergic reactions to the human body even if it remains in the asparagus resin. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0024] In view of the problem that the asparagus resin prepared by using diethyl maleate in the prior art has excessively high content of diethyl maleate and / or diethyl fumarate, which causes allergic reaction to the human body, and the problem that the content of diethyl maleate and / or diethyl fumarate in the asparagus resin is reduced by using a short-range molecular distillation method, which causes high equipment investment, long production cycle, low production efficiency, etc., the inventor unexpectedly discovered that maleic acid diol esters and fumaric acid diol esters prepared by using C4 or higher alkyl alcohols as reaction raw materials have almost no irritation to human skin. Based on this, the present invention proposes a low-allergenic asparagus resin, comprising a secondary amino resin having a structure shown in the following formula (1) and diethyl fumarate and / or diethyl maleate accounting for no more than 0.5% of the weight of the asparagus resin,

[0025]

[0026] Wherein, X is selected from a divalent organic structure with an average molecular weight of 50-5000 which is inert to react with isocyanate groups at 100° C. after removing two primary amino groups from a diamine compound, Et represents an ethyl group, R1 is selected from a C2-C8 alkyl group, and the molar percentage of the C4-C8 alkyl group in R1 is not less than 10%.

[0027] In the present invention, the ester structure of the secondary amino resin represented by formula (1) contains a C4-C8 alkyl group in a certain proportion, and the content of diethyl fumarate and / or diethyl maleate in the asparagine resin does not exceed 0.5% without affecting the curing performance of the asparagine resin, thereby avoiding allergenicity to the human body.

[0028] In a preferred embodiment of the present invention, the molar percentage of C4-C8 alkyl in R1 is not less than 20%. For example, the molar percentage of C4-C8 alkyl in R1 can be any value of 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc., without special restrictions. For example, R1 can be a combination of ethyl and C4 alkyl in a molar ratio of 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, etc. More preferably, the molar percentage of C4-C8 alkyl in R1 is not higher than 80%. Since C4-C8 alkyl has a longer chain length than ethyl and a stronger internal plasticizing effect, if the molar percentage of C4-C8 alkyl in R1 is too high, the tensile strength of asparagus resin will be greatly reduced, but the elongation at break will be significantly improved.

[0029] In a preferred embodiment of the present invention, the sum of the weight percentages of diethyl fumarate and diethyl maleate in asparagus resin does not exceed 0.5%. Both diethyl fumarate and diethyl maleate can cause allergic reactions, and the lower the sum of the weight percentages of these two substances, the better. It is generally believed that the sum of the weight percentages does not exceed 0.5%, which has very low allergenicity to the human body or is basically considered to be non-allergenic to the human body.

[0030] In a preferred embodiment of the present invention, the diamine compound is selected from 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 1-methyl-2,4-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, o-diaminomethylcyclopentane and polyetheramine, or a combination of two or more thereof. The diamine compounds used in the present invention are all commonly used diamine compounds in the art, generally including cycloalkylamines and polyetheramines. For example, the polyetheramine may be polyetheramine D-230, polyetheramine D-400, polyetheramine D-2000, polyetheramine ED-600, polyetheramine ED-900, polyetheramine T-403, polyetheramine T-5000, etc., which can be directly purchased from the market.

[0031] Another aspect of the present invention provides a method for preparing a low-allergenic asparagine resin as described in any of the above embodiments, wherein diethyl maleate is slowly added dropwise to the diamine compound in a molar ratio of diamine compound to diethyl maleate of 1:0.5-0.95 under stirring, and after the addition is completed, the temperature is raised to 40-70° C. for reaction until the sum of the weight percentages of diethyl maleate and diethyl fumarate does not exceed 0.5%, and a maleate ester as shown in the structure of the following formula (2) is added, the temperature is adjusted to 60-100° C. for reaction for 24-96 hours, and then the temperature is maintained at 80-100° C. and vacuumed to remove low-boiling substances, thereby obtaining a low-allergenic asparagine resin;

[0032] R2OCOCH=CHCOOR2 (2)

[0033] Wherein, R2 is selected from C4-C8 alkyl.

[0034] In the above preparation of the present invention, the diamine compound is first used in excess relative to diethyl maleate, which has the following effects: (A) promoting the complete reaction of diethyl maleate as much as possible; (B) reducing the reaction temperature to minimize the conversion of diethyl maleate into diethyl fumarate with low reaction activity; (C) increasing the reaction rate; and then adding the maleate shown in formula (2) to completely react the excess diamine compound to avoid the residual diamine compound from affecting the operation time of the asparagine resin. In the present invention, the maleate shown in formula (2) is used, and the ester group is connected to a C4-C8 alkyl group. The maleate shown in formula (2) has a higher molecular weight and boiling point than diethyl maleate / diethyl fumarate, and is very low in allergenicity to the human body.

[0035] In the above-mentioned preparation method of the present invention, the reaction process monitoring can be detected and monitored by high performance liquid chromatography or gas chromatography. The specific operation method of high performance liquid chromatography can refer to the prior art "High Performance Liquid Chromatography for Determination of Diethyl Maleate" (Zhejiang Chemical Industry, Vol. 37, No. 7, 2006, 21-22).

[0036] In a preferred embodiment of the present invention, R2 is selected from C4 alkyl. The inventor unexpectedly found that when synthesizing maleic acid diol esters and fumaric acid diol esters, the higher the carbon number of the alkyl alcohol, the lower the sensitization produced. For example, the sensitization of dibutyl maleate is much lower than that of diethyl maleate, but the reactivity is also reduced at the same time. The reactivity of dibutyl maleate is lower than that of diethyl maleate. Considering the reactivity and sensitization to the human body, it is more appropriate for R2 to be selected from C4 alkyl. Specifically, the C4 alkyl can be n-butyl or isobutyl, and the maleate shown in the structure of formula (2) can be dibutyl maleate or diisobutyl maleate.

[0037] In a preferred embodiment of the present invention, the diamine compound is selected from 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 1-methyl-2,4-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, o-diaminomethylcyclopentane and polyetheramine, or a combination of two or more thereof.

[0038] In a preferred embodiment of the present invention, the molar ratio of the primary amino group to diethyl maleate in the diamine compound is 1:0.5-0.9. For example, the molar ratio of the primary amino group to diethyl maleate in the diamine compound can be any value of 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, 1:0.85, 1:0.9, etc., without any particular limitation.

[0039] In a preferred embodiment of the present invention, the molar ratio of the primary amino group to the maleate in the diamine compound is 1:0.1-0.6. For example, the molar ratio of the primary amino group to the maleate in the diamine compound can be any value of 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, etc., without any particular limitation.

[0040] In a preferred embodiment of the present invention, the ratio of the number of moles of primary amino groups in the diamine compound to the sum of the number of moles of diethyl maleate and maleate is 1:1-1.1. The sum of the number of moles of diethyl maleate and maleate is sufficient or excessive compared to the number of moles of primary amino groups in the diamine compound, which can promote the complete reaction of the diamine compound and minimize the residual primary amino groups. For example, the ratio of the number of moles of primary amino groups in the diamine compound to the sum of the number of moles of diethyl maleate and maleate can be any value of 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.05, 1:1.07, 1:1.08, 1:1, etc., without special restrictions.

[0041] The technical solution of the present invention is further described and illustrated according to various embodiments below.

[0042] Example 1

[0043] Add 210.4g (1mol) of 4,4'-diaminodicyclohexylmethane to a four-necked flask, slowly drop 275.5g (1.6mol) of diethyl maleate, and react at 45°C for 72h after the addition is completed. Sampling is performed by high performance liquid chromatography to determine that the sum of the weight percentages of diethyl maleate and diethyl fumarate in the reaction mass is 0.03%. Add 136.8g (0.6mol) of diisobutyl maleate, and keep the temperature at 75°C for 96h. Vacuum for 1h at 80°C-85°C and -0.099MPa to obtain a low-sensitivity asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product is 0.14% by high performance liquid chromatography.

[0044] According to the reaction results, in the secondary amino resin of the structure shown in the above formula (1), the molar percentage of the isobutyl group in R1 is about 40%.

[0045] Example 2

[0046] The difference between this embodiment and embodiment 1 is that in embodiment 1, the weight of diisobutyl maleate is adjusted from 136.8 g to 114.2 g (0.5 mol). The remaining steps remain unchanged, and the sum of the weight percentages of diethyl maleate and diethyl fumarate in the obtained hypoallergenic asparagine resin measured by high performance liquid chromatography is 0.15%.

[0047] According to the reaction results, in the secondary amino resin of the structure shown in the above formula (1), the molar percentage of the isobutyl group in R1 is about 40%.

[0048] Example 3

[0049] Add 210.4g (1mol) of 4,4'-diaminodicyclohexylmethane to a four-necked flask, slowly drop 172.2g (1mol) of diethyl maleate, and react at 60°C for 50h after the addition is completed. Sampling is performed by high performance liquid chromatography to determine that the sum of the weight percentages of diethyl maleate and diethyl fumarate in the reaction material is 0.15%. Add 251.3g (1.1mol) of diisobutyl maleate, and keep the temperature at 80°C for 84h. Vacuum for 1h at 85°C-90°C and -0.099MPa to obtain a low-sensitivity asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product is 0.24% by high performance liquid chromatography.

[0050] According to the calculation results of the reaction, in the secondary amino resin of the structure shown in the above formula (1), the molar percentage of the isobutyl group in R1 is about 100%.

[0051] Example 4

[0052] Add 210.4g (1mol) of 4,4'-diaminodicyclohexylmethane to a four-necked flask, slowly drop 206.6g (1.2mol) of diethyl maleate, and react at 60°C for 58h after the addition is completed. Sampling is performed by high performance liquid chromatography to determine that the sum of the weight percentages of diethyl maleate and diethyl fumarate in the reaction material is 0.07%. Add 228.3g (1mol) of diisobutyl maleate, and keep the temperature at 90°C for 60h. Keep the vacuum at 85°C-90°C and -0.099MPa for 1h to obtain a low-sensitivity asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product is 0.13% by high performance liquid chromatography.

[0053] According to the calculation results of the reaction, in the secondary amino resin of the structure shown in the above formula (1), the molar percentage of the isobutyl group in R1 is about 80%.

[0054] Example 5

[0055] Add 210.4g (1mol) of 4,4'-diaminodicyclohexylmethane to a four-necked flask, slowly drop 310g (1.8mol) of diethyl maleate, and after the dropwise addition, control the reaction at 70°C for 60h. Sampling and high performance liquid chromatography are used to measure the sum of the weight percentages of diethyl maleate and diethyl fumarate in the reaction material to be 0.35%. Add 57.1g (0.25mol) of diisobutyl maleate, and keep the temperature at 90°C for 50h. Keep the vacuum at 85°C-90°C and -0.099MPa for 1h to obtain a low-sensitivity asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product is 0.44% by high performance liquid chromatography.

[0056] According to the reaction results, in the secondary amino resin of the structure shown in the above formula (1), the molar percentage of the isobutyl group in R1 is about 20%.

[0057] Comparative Example 1

[0058] 210.4 g (1 mol) of 4,4'-diaminodicyclohexylmethane was added into a four-necked flask, and 361.6 g (2.1 mol) of diethyl maleate was slowly added dropwise. After the addition was completed, the reaction was controlled at 60°C for 96 hours, and the vacuum was maintained at 130°C-135°C and -0.099 MPa for 1 hour to obtain asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product asparagus resin was measured by high performance liquid chromatography, and the weight percentage of diethyl fumarate in the product asparagus resin was 2.4%. The weight percentage of diethyl fumarate in the product asparagus resin was measured by high performance liquid chromatography and was 2.2%.

[0059] Example 6

[0060] Add 238.2g (1mol) 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane to a four-necked flask, slowly drop 275.5g (1.6mol) diethyl maleate, and react at 70°C for 72h after the dropwise addition is completed. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the reaction material is 0.04% by high performance liquid chromatography. Add 114.2g (0.5mol) di-n-butyl maleate, and keep the temperature at 90°C for 55h. Keep the vacuum at 85°C-90°C and -0.099MPa for 1h to obtain a low-sensitivity asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product is 0.15% by high performance liquid chromatography.

[0061] According to the reaction results, in the secondary amino resin of the structure shown in the above formula (1), the molar percentage of the isobutyl group in R1 is about 40%.

[0062] Comparative Example 2

[0063] 238.2 g (1 mol) of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane was added to a four-necked flask, and 361.6 g (2.1 mol) of diethyl maleate was slowly added dropwise. After the addition was completed, the reaction was controlled at 70°C for 96 hours, and vacuum was applied for 1 hour at 130°C-135°C and -0.099 MPa to obtain asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product asparagus resin was measured by high performance liquid chromatography and was 2.5%. The weight percentage of diethyl fumarate in the product asparagus resin was measured by high performance liquid chromatography and was 2.4%.

[0064] Example 7

[0065] Add 230g (1mol) of polyetheramine D-230 to a four-necked flask, slowly drop 240.1g (1.4mol) of diethyl maleate, and react at 65°C for 72h after the addition is completed. Sampling is performed by high performance liquid chromatography to determine that the sum of the weight percentages of diethyl maleate and diethyl fumarate in the reaction mass is 0.05%. Add 136.8g (0.6mol) of diisobutyl maleate, and keep the temperature at 80°C for 72h. Keep the temperature at 90°C-95°C and -0.098MPa for 1h to obtain a low-sensitivity asparagus resin. The sum of the weight percentages of diethyl maleate and diethyl fumarate in the product is 0.17% by high performance liquid chromatography.

[0066] According to the calculation results of the reaction, in the secondary amino resin of the structure shown in the above formula (1), the molar percentage of the isobutyl group in R1 is about 60%.

[0067] Performance test comparison

[0068] The polyaspartic acid coating was prepared according to the following formulation.

[0069] Component A: It is composed of 64% asparagus resin, 5% hydroxy acrylic resin, 5% titanium dioxide, 25% barium sulfate, 0.2% dispersant, 0.4% defoamer, 0.2% leveling agent and 0.2% anti-settling agent.

[0070] Component B: It is composed of an adduct curing agent prepared from 3% HDI trimer, 10% HMDI and 87% IPDI and polyether polyol.

[0071] Component A and component B are mixed evenly in a ratio of the total molar content of secondary amine and hydroxyl groups in component A: the molar content of isocyanate groups NCO in component B = 1:1.05 to obtain a polyaspartic acid ester coating. The obtained polyaspartic acid ester coating is made into a coating film with a thickness of 0.5 mm, cured at 35±2°C for 15 days, and referred to the test methods and indicators of T / CWA204-2021 "Asparagine Polyurea Waterproof Coating Standard". The test performance data results are shown in Table 1.

[0072] Table 1 Performance data

[0073]

[0074] It can be seen from the data results in Table 1 that the low-allergenic asparagine resin of the present invention is relatively close to the asparagine resin obtained by the conventional preparation method in terms of performance.

[0075] The sum of the contents of diethyl maleate and diethyl fumarate in the low-allergenic asparagine resin of the present invention is very low, so it can also be physically blended with existing asparagine resins (such as Feiyang Junyan's F420 resin, F520 resin, etc.) to reduce the contents of diethyl maleate and diethyl fumarate in the existing asparagine resins. Under the condition that the curing performance remains basically unchanged, the allergenicity of the asparagine resin is significantly reduced.

[0076] The blending ratio of the low-allergenic asparagine resin of the present invention and the existing asparagine resin can be 1:1, 2:1, etc. by weight. For example, the low-allergenic asparagine resin of Example 1 of the present invention and the F420 resin are blended in a weight ratio of 1:1, and in the obtained asparagine resin composition, the sum of the weight percentages of diethyl maleate and diethyl fumarate can be reduced to 1.5% or less, such as 1.3%, 1.2%, and lower weight percentages of diethyl maleate and diethyl fumarate mean lower allergenicity. The curing performance of the asparagine resin composition is basically close to that of the F420 resin, and the various performance indicators of the asparagine resin composition are basically within the range of 95-105% of the performance indicators of the F420 resin.

[0077] 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 hypoallergenic asparagine resin, characterized in that: The invention comprises a secondary amino resin having a structure as shown in the following formula (1) and diethyl fumarate and / or diethyl maleate in an amount not exceeding 0.5% by weight of the asparagine resin. Wherein, X is selected from a divalent organic structure with an average molecular weight of 50-5000 which is inert to react with isocyanate groups at 100° C. and which remains after two primary amino groups are removed from a diamine compound; Et represents an ethyl group; R1 is selected from a C2-C8 alkyl group; and the molar percentage of the C4-C8 alkyl group in R1 is not less than 10%.

2. The hypoallergenic asparagine resin according to claim 1, characterized in that The molar percentage of C4-C8 alkyl in R1 is not less than 20%.

3. The hypoallergenic asparagine resin according to claim 1, characterized in that The sum of the weight percentages of the diethyl fumarate and the diethyl maleate in the asparagine resin does not exceed 0.5%.

4. The hypoallergenic asparagine resin according to claim 1, characterized in that The diamine compound is selected from one or a combination of two or more of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 1-methyl-2,4-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, o-diaminomethylcyclopentane and polyetheramine.

5. A method for preparing the hypoallergenic asparagine resin according to any one of claims 1 to 4, characterized in that: According to the molar ratio of the diamine compound to diethyl maleate of 1:0.5-0.95, the diethyl maleate is slowly added dropwise to the diamine compound under stirring, and after the addition is completed, the temperature is raised to 40-70° C. for reaction until the sum of the weight percentages of diethyl maleate and diethyl fumarate does not exceed 0.5%, and the maleate ester shown in the structure of the following formula (2) is added, the temperature is adjusted to 60-100° C. for reaction for 24-96 hours, and then the temperature is maintained at 80-100° C. to remove low-boiling substances by vacuum, thereby obtaining the low-allergenic asparagine resin; R2OCOCH=CHCOOR2 (2) Wherein, R2 is selected from C4-C8 alkyl.

6. The method for preparing the hypoallergenic asparagine resin according to claim 5, characterized in that: The R2 is selected from C4 alkyl.

7. The method for preparing the hypoallergenic asparagine resin according to claim 5, characterized in that: The diamine compound is selected from one or a combination of two or more of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, 1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 1-methyl-2,4-cyclohexanediamine, 1,3-cyclohexanedimethylamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, o-diaminomethylcyclopentane and polyetheramine.

8. The method for preparing the hypoallergenic asparagine resin according to claim 5, characterized in that: The molar ratio of the primary amino group in the diamine compound to the diethyl maleate is 1:0.5-0.

9.

9. The method for preparing the hypoallergenic asparagine resin according to claim 5, characterized in that: The molar ratio of the primary amino group in the diamine compound to the maleate is 1:0.1-0.

6.

10. The method for preparing the hypoallergenic asparagine resin according to claim 5, characterized in that: The ratio of the molar number of the primary amino group in the diamine compound to the sum of the molar numbers of the diethyl maleate and the maleic acid ester is 1:1-1.1.

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