Glyoxal-urea resin and its preparation method and application

Abstract

The application relates to the technical field of new materials, and discloses a glyoxal-urea resin as well as a preparation method and application thereof. The preparation method of the glyoxal-urea resin comprises the following steps: taking a phthalic anhydride derivative, glyoxal and urea as monomers, and co-condensing to obtain the glyoxal-urea resin. The glyoxal-urea resin provided by the application has a heat conductivity coefficient of 0.017 W / (m*K), and has high heat preservation and insulation performance. The glyoxal-urea resin provided by the application has a tensile strength of 34 MPa and a bending strength of 75 MPa, and has high mechanical performance.

Description

A glyoxal-urea resin, its preparation method and application Technical Field

[0001] This invention relates to the field of new materials technology, and more specifically, to a glyoxal-urea resin, its preparation method, and its application. Background Technology

[0002] Against the backdrop of global advocacy for energy conservation, emission reduction, and green development, the application of thermal insulation materials in buildings, industrial pipelines, cold chain transportation, and other fields is becoming increasingly crucial. Resin-based thermal insulation materials, with their high plasticity and ease of processing, have become a key research and development area in the industry. However, traditional glyoxal-urea resin has a high thermal conductivity, which cannot meet the requirements for high-efficiency thermal insulation. To improve the thermal insulation performance of glyoxal-urea resin, those skilled in the art have attempted to modify it by adding fillers and altering the crosslinking structure. However, these methods suffer from problems such as short-lasting modification effects, decreased material mechanical properties, and increased production costs, limiting its widespread application in the field of thermal insulation. Therefore, developing a novel glyoxal-urea resin with excellent thermal insulation performance has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0003] The purpose of this invention is to provide a glyoxal-urea resin, its preparation method, and its application.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] One of the technical solutions of this invention:

[0006] A method for preparing glyoxal-urea resin includes the following steps:

[0007] The glyoxal-urea resin was obtained by copolymerization of phthalic anhydride derivatives, glyoxal, and urea as monomers.

[0008] Furthermore, the structural formula of the phthalic anhydride derivative is as follows:

[0009]

[0010] Furthermore, the method for preparing the phthalic anhydride derivative includes the following steps:

[0011] Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in an organic solvent and reacted with ethylenediamine as a catalyst to obtain the phthalic anhydride derivative.

[0012] Furthermore, the molar ratio of the phenyldichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione is 1:0.8.

[0013] Furthermore, the organic solvent is anhydrous acetone or anhydrous tetrahydrofuran.

[0014] Furthermore, the reaction is specifically carried out in a nitrogen atmosphere at room temperature for 12 hours.

[0015] In this invention, the preparation equation for the phthalic anhydride derivative is as follows:

[0016]

[0017] Further, the molar ratio of the phthalic anhydride derivative, glyoxal, and urea is (0.05–0.15):1:(0.1–0.5).

[0018] Furthermore, the co-condensation specifically refers to:

[0019] Phthalic anhydride derivatives, glyoxal, and urea were placed in an organic solvent and copolymerized at 40–70 °C for 30–90 min using aluminum trichloride as a catalyst.

[0020] Furthermore, the organic solvent is N,N-dimethylacetamide or dimethyl sulfoxide.

[0021] The second technical solution of this invention:

[0022] The glyoxal-urea resin prepared by the above-mentioned method is an example of a glyoxal-urea resin preparation method.

[0023] The third technical solution of this invention:

[0024] The above-mentioned glyoxal-urea resin is used in coatings, packaging materials, and building materials.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The glyoxal-urea resin provided by this invention has a thermal conductivity of up to 0.017 W / (m·K), exhibiting high thermal insulation performance;

[0027] The present invention provides a glyoxal-urea resin with a tensile strength of up to 34 MPa and a flexural strength of up to 75 MPa, exhibiting high mechanical properties. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0029] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0033] The following embodiments illustrate a method for preparing glyoxal-urea resin, comprising the following steps:

[0034] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in an organic solvent with ethylenediamine as a catalyst and reacted at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0035] The organic solvent is anhydrous acetone or anhydrous tetrahydrofuran;

[0036] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) are placed in an organic solvent and copolymerized at 40–70 °C for 30–90 min with aluminum trichloride as a catalyst, according to a molar ratio of (0.05–0.15):1:(0.1–0.5), to obtain the glyoxal-urea resin.

[0037] The organic solvent is N,N-dimethylacetamide or dimethyl sulfoxide.

[0038] Example 1

[0039] A glyoxal-urea resin

[0040] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0041] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.05:1:0.1, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.05 G1U 0.1 .

[0042] Example 2

[0043] A glyoxal-urea resin

[0044] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0045] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.07:1:0.1, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.07 G1U 0.1 .

[0046] Example 3

[0047] A glyoxal-urea resin

[0048] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0049] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.09:1:0.1, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.09 G1U 0.1 .

[0050] Example 4

[0051] A glyoxal-urea resin

[0052] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0053] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.11:1:0.1, using aluminum trichloride as a catalyst, and copolymerized at 40°C for 60 min to obtain the glyoxal-urea resin, denoted as P. 0.11 G1U 0.1 .

[0054] Example 5

[0055] A glyoxal-urea resin

[0056] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0057] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.1, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.1 .

[0058] Example 6

[0059] A glyoxal-urea resin

[0060] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0061] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.15:1:0.1, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.15 G1U 0.1 .

[0062] Comparative Example 1

[0063] A glyoxal-urea resin

[0064] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0065] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.03:1:0.1, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.03 G1U 0.1 .

[0066] Comparative Example 2

[0067] A glyoxal-urea resin

[0068] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0069] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.17:1:0.1, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.17G1U 0.1 .

[0070] The thermal insulation performance of the glyoxal-urea resins prepared in Examples 1-6 and Comparative Examples 1-2 was tested, and the results are shown in Table 1.

[0071] Table 1. Test results of thermal insulation performance

[0072]

[0073]

[0074] As shown in Table 1, the thermal conductivity of the prepared glyoxal-urea resin gradually decreases with the increase of phthalic anhydride derivative addition, indicating that the thermal insulation performance of glyoxal-urea resin gradually improves. However, with the excessive addition of phthalic anhydride derivative, the thermal conductivity of the prepared glyoxal-urea resin gradually increases, indicating that the thermal insulation performance of glyoxal-urea resin gradually decreases.

[0075] Example 7

[0076] A glyoxal-urea resin

[0077] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0078] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.2, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.2 .

[0079] Example 8

[0080] A glyoxal-urea resin

[0081] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0082] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.3, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.3 .

[0083] Example 9

[0084] A glyoxal-urea resin

[0085] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0086] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.4, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.4 .

[0087] Example 10

[0088] A glyoxal-urea resin

[0089] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0090] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.5, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.5 .

[0091] Comparative Example 3

[0092] A glyoxal-urea resin

[0093] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0094] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.05, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.05 .

[0095] Comparative Example 4

[0096] A glyoxal-urea resin

[0097] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0098] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.6, and co-condensed at 40°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.6 .

[0099] The thermal insulation performance of the glyoxal-urea resins prepared in Examples 7-10 and Comparative Examples 3-4 was tested, and the results are shown in Table 2.

[0100] Table 2 Results of Thermal Insulation Performance Tests

[0101]

[0102] As shown in Table 2, the thermal conductivity of the prepared glyoxal-urea resin gradually decreases with increasing urea content, indicating that the thermal insulation performance of the glyoxal-urea resin gradually improves. However, with excessive urea addition, the thermal conductivity of the prepared glyoxal-urea resin gradually increases, indicating that the thermal insulation performance of the glyoxal-urea resin gradually decreases.

[0103] Example 11

[0104] A glyoxal-urea resin

[0105] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0106] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.3, and co-condensed at 50°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.3 50.

[0107] Example 12

[0108] A glyoxal-urea resin

[0109] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0110] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.3, and co-condensed at 60°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.3 60.

[0111] Example 13

[0112] A glyoxal-urea resin

[0113] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0114] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.3, and co-condensed at 70°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.3 70.

[0115] Comparative Example 5

[0116] A glyoxal-urea resin

[0117] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0118] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide with a molar ratio of 0.13:1:0.3 and aluminum trichloride was used as a catalyst. The mixture was then co-condensed at 30°C for 60 min.

[0119] Due to the low co-condensation temperature, it is impossible to prepare glyoxal-urea resin.

[0120] Comparative Example 6

[0121] A glyoxal-urea resin

[0122] 1) Phenyl dichlorosilane and 5,6-dihydroxyisobenzofuran-1,3-dione were placed in anhydrous tetrahydrofuran at a molar ratio of 1:0.8, and ethylenediamine was used as a catalyst. The reaction was carried out at room temperature for 12 h under a nitrogen atmosphere to obtain phthalic anhydride derivatives.

[0123] 2) The phthalic anhydride derivative (P), glyoxal (G), and urea (U) were placed in N,N-dimethylacetamide at a molar ratio of 0.13:1:0.3, and co-condensed at 80°C for 60 min using aluminum trichloride as a catalyst to obtain the glyoxal-urea resin, denoted as P. 0.13 G1U 0.3 80.

[0124] The thermal insulation performance of the glyoxal-urea resins prepared in Examples 11-13 and Comparative Example 6 was tested, and the results are shown in Table 3.

[0125] Table 3. Test results of thermal insulation performance

[0126]

[0127] As shown in Table 3, a higher cocondensation temperature is beneficial to the thermal insulation performance of glyoxal-urea resin. However, an excessively high cocondensation temperature will reduce the thermal insulation performance of glyoxal-urea resin.

[0128] The P prepared in Example 11 0.13 G1U 0.3 The mechanical properties of 50 were tested;

[0129] Upon testing, P 0.13 G1U 0.3 The tensile strength of 50 is 34 MPa and the flexural strength is 75 MPa, which indicates that the glyoxal-urea resin provided by the present invention maintains high mechanical properties while improving thermal insulation performance.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A type of glyoxal A method for preparing urea resin, characterized in that, Includes the following steps: The glyoxal was obtained by copolymerization of phthalic anhydride derivative, glyoxal, and urea as monomers. Urea resin; the structural formula of the phthalic anhydride derivative is: The method for preparing the phthalic anhydride derivative includes the following steps: mixing phenyl dichlorosilane and 5,6... Dihydroxyisobenzofuran 1,3 The diketone is placed in an organic solvent and reacted with ethylenediamine as a catalyst to obtain the phthalic anhydride derivative.

2. The glyoxal according to claim 1 A method for preparing urea resin, characterized in that, The phenyl dichlorosilane and 5,6 Dihydroxyisobenzofuran 1,3 The molar ratio of the diketones is 1:0.

8.

3. The glyoxal according to claim 1 A method for preparing urea resin, characterized in that, The organic solvent is anhydrous acetone or anhydrous tetrahydrofuran.

4. The glyoxal according to claim 1 A method for preparing urea resin, characterized in that, The reaction is specifically carried out in a nitrogen atmosphere at room temperature for 12 hours.

5. The glyoxal according to claim 1 A method for preparing urea resin, characterized in that, The molar ratio of the phthalic anhydride derivative, glyoxal, and urea is (0.05–0.15):1:(0.1–0.5).

6. The glyoxal according to claim 1 A method for preparing urea resin, characterized in that, The cocondensation specifically involves placing phthalic anhydride derivatives, glyoxal, and urea in an organic solvent, using aluminum trichloride as a catalyst, and cocondensing at 40–70°C for 30–90 min.

7. The glyoxal according to claim 6 A method for preparing urea resin, characterized in that, The organic solvent is N,N Dimethylacetamide or dimethyl sulfoxide.

8. A glyoxal according to any one of claims 1 to 7 Glyoxal prepared by the preparation method of urea resin Urea resin.

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