Preparation and application of amino resin based on furyl amine monomer

Abstract

The invention discloses preparation and application of amino resin based on furyl amine monomers. The novel furyl amine monomer is firstly provided and used for preparing the amino resin, and the furyl amino resin prepared based on the furyl amine monomer has the advantages of being high in curing efficiency, stable in product, high in adhesive strength and shear strength, environmentally friendly and the like, and is suitable for the field of adhesives for new-generation electronic and electrical appliances. In addition, the method is convenient to operate, simple and easy to implement, the raw materials are low in price, and the method has great significance in improving the comprehensive performance of the novel furan amino resin and reducing the production cost.

Description

Technical Field

[0001] The invention belongs to the field of chemical synthesis and high molecular polymer synthesis, and specifically relates to the preparation and application of an amino resin based on furanylamine monomers. Background Art

[0002] Amino resin refers to a thermosetting resin obtained by polycondensation of amino compounds with formaldehyde. Its varnish has light color, high gloss, high hardness, and good electrical insulation; the color paint has a full appearance, bright colors, excellent adhesion, good aging resistance, and good resistance; at the same time, its drying time is short, the construction is convenient, and it is conducive to the continuous operation of painting. Due to the above advantages of amino resin, it has been widely used in vehicles, household appliances, light industrial products, machine tools, etc. However, the currently synthesized amino resin contains a large amount of aldehyde and has certain carcinogenicity. Technicians try to replace the amino materials required in the production process with bio-based materials to reduce the use of petroleum fossil resources. Therefore, using renewable biomass resources to replace or transform traditional adhesives for electronic appliances has become an important way to respond to the construction of ecological civilization and the sustainable development strategy.

[0003] Existing amino resins usually have synthetic components including formaldehyde solution, melamine, and alkali solution, which are then synthesized through modification treatments such as etherification. They have problems such as weak adhesion and short storage period. For example, melamine formaldehyde resin is clear when it is produced, but its shear strength is between 0.5 and 2 MPa, and it will generally become turbid and solidify in about half a day during storage, and cannot be used the next day. This shows that traditional amino resins have shortcomings such as poor stability, weak adhesion, and high cost of use. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a preparation and application of an amino resin based on furanylamine monomers. The furanylamino resin prepared based on the furanylamine monomers of the present invention has the advantages of high curing efficiency, stable product, high adhesion and shear strength, green environmental protection, etc., and is suitable for the field of adhesives for new generation electronic appliances.

[0005] The present invention firstly provides a novel furanylamine monomer, which comprises one or a mixture of monofuranylamine monomer, bisfuranylamine monomer and polyfuranylamine monomer.

[0006] The monofuranylamine monomer is selected from the compounds of the following structures:

[0007]

[0008] The bisfuranylamine monomer is selected from the compounds of the following structures:

[0009]

[0010] Wherein X is selected from *-(CH 2 ) n -*(n=1-5), *Indicates the connection location.

[0011] The polyfuranylamine monomer is selected from the compounds of the following structures:

[0012]

[0013] in

[0014] The furanylamine monomer of the present invention is prepared by the following method:

[0015] First, furanyl aldehydes (10 mmol) were added to a high-pressure reactor, and then catalyst Raney Ni (5 wt%) and THF (150 mL) were added, ammonia (0.5 MPa) and hydrogen (1.0 MPa) were introduced, and the mixture was reacted at 100-150° C. for 0.5-24 h. After filtering and drying, furanyl amine monomers were obtained.

[0016] The furanyl aldehydes are selected from compounds of the following structures:

[0017]

[0018] The group scopes of X and Y are consistent with the above definitions.

[0019] The reaction temperature is 100-150°C and the reaction time is 0.5-24h.

[0020] Further preferably, the reaction temperature is 140° C. and the reaction time is 12 h.

[0021] The method for preparing an amino resin based on the furanylamine monomer of the present invention comprises the following steps:

[0022] Step 1: adding an alkaline solution to the aldehyde monomer solution to adjust the pH value of the system, and keeping the temperature at the first reaction temperature for reaction;

[0023] Step 2: After the heat preservation reaction in the first temperature range is completed, furanylamine monomers and catalysts are added to the system in batches and reacted under stirring;

[0024] Step 3: adding the aldehyde monomer solution to the system again, and controlling the system to react at a second reaction temperature;

[0025] Step 4: Raise the system temperature to the third reaction temperature while stirring. When the preset viscosity value is reached, the reaction is completed to obtain a clear and transparent amino resin.

[0026] In step 1, the aldehyde monomer is selected from one or a mixture of two of formaldehyde, acetaldehyde, succinaldehyde, 2,5-furandicarboxaldehyde, valeraldehyde, adipaldehyde, benzaldehyde, phenylpropionaldehyde, citral, etc., and more preferably formaldehyde and / or 2,5-furandicarboxaldehyde. The concentration of the aldehyde monomer solution is 0.5-20 mol / L, and more preferably 5-10 mol / L. The water-to-liquid mass ratio in the system is 50:50 (water accounts for 50wt% in the liquid reaction system).

[0027] In step 1, the alkaline solution is selected from sodium hydroxide solution, potassium hydroxide solution, potassium bicarbonate solution, sodium carbonate solution, potassium tert-butoxide solution or ammonia solution, and is more preferably sodium hydroxide solution or sodium carbonate solution. The concentration of the alkaline solution is 0.5-2 mol / L, and is more preferably 1 mol / L.

[0028] In step 1, the pH value of the system is adjusted to 8-11, preferably 9, using the alkaline solution.

[0029] In step 1, the first reaction temperature is 20-30°C, more preferably 25°C.

[0030] In step 2, the catalyst is selected from polyvinyl chloride (PVC), dibutyltin dilaurate (DBTDL), magnesium oxide, Pd-Fe or azoisobutyronitrile, and is more preferably azoisobutyronitrile (AIBN); the concentration of the catalyst in the reaction system is 0.01-5wt%, and is more preferably 1wt%.

[0031] In step 3, the second reaction temperature is 30-50°C, more preferably 45°C.

[0032] In step 4, the third reaction temperature is 50-90° C., more preferably 70° C. The system temperature is raised to the third reaction temperature under stirring, and the heating rate is 0.5-5° C. / min, more preferably 2° C. / min.

[0033] In step 4, the preset viscosity value is 5000-500000 cP, and more preferably 20000 cP.

[0034] In the above preparation process, the aldehyde monomer is added twice, and the mass of the aldehyde monomer added in step 1 is twice the mass of the aldehyde monomer added in step 3. In addition, the ratio of the total mass of the aldehyde monomer added to the reaction system to the mass of the furanylamine monomer is 1:1 to 3:1.

[0035] The concentration of the furanylamine monomer in the reaction system is 1-25 mol / L, more preferably 15 mol / L.

[0036] Application of the amino resin prepared by the invention in preparing adhesives.

[0037] Furthermore, the adhesive is a metal adhesive.

[0038] The bonding strength of the amino resin prepared by the present invention is 30-50 MPa, more preferably 50 MPa.

[0039] The amino resin prepared by the present invention has greatly enhanced adhesion, a peel strength with a metal substrate of 10-50 MPa, and a greatly extended storage time, which can be extended to 15 days, greatly improving the convenience of transportation and use of the amino resin and avoiding waste; the introduction of furan bio-based amino monomers exhibits high adhesion, high stability and eco-friendly properties.

[0040] In addition, the method of the present invention is easy to operate, simple and feasible, and the raw material price is relatively low, which is of great significance for improving the comprehensive performance of the novel furan amino resin and reducing the production cost.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The curing efficiency is high and the product is stable, which prolongs the storage time of amino resin.

[0043] 2. The introduction of furan ring improves the adhesion and shear strength of amino resin.

[0044] 3. The introduction of furan amine monomers and the amino resins developed as raw materials as bio-based materials can meet green environmental protection requirements and conform to the development of new bio-based materials in the dual carbon strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in describing the embodiments or the prior art are briefly introduced below.

[0046] Figure 1 The present invention is a flow chart for preparing the novel furanamine monomer and amino resin thereof. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] The method for preparing the novel furanylamine monomer in the embodiment of the present invention comprises the following steps:

[0049] First, furanyl aldehydes (10 mmol) were added to a high-pressure reactor, followed by RaneyNi (5 wt%) and THF (150 mL), and ammonia (0.5 MPa) and hydrogen (1.0 MPa) were introduced. The reaction temperature range was 100-150° C., and the reaction time range was 0.5-24 h. After filtration and spin drying, furanyl amines were obtained.

[0050] The preparation method of the amino resin in the embodiment of the present invention comprises the following steps:

[0051] The method comprises the following steps: adding a sodium hydroxide solution to an aldehyde monomer solution and stirring the solution; when the desired pH value range is reached, keeping the solution warm at a first reaction temperature; adding a novel furanylamine monomer after the keeping warm is completed; adding a catalyst and stirring the solution; adding the aldehyde monomer solution again and stirring the solution, and controlling the system temperature at a second reaction temperature; stirring the solution and heating the solution to a third reaction temperature to obtain a clear amino resin; and when the viscosity of the clear amino resin reaches a preset viscosity value, the reaction is completed.

[0052] Example 1: Preparation of novel furanylamine monomers - Optimization of reaction temperature

[0053] First, furan dicarboxaldehyde (10 mmol) was added to a high pressure reactor, followed by Raney Ni (5 wt%) and THF (150 mL), and ammonia (0.5 MPa) and hydrogen (1.0 MPa) were introduced. The reaction temperature range was 100-150°C, and the reaction time was 12 h. After filtration and spin drying, furanyl amines were obtained.

[0054] Example 2: Preparation of novel furanylamine monomers - Optimization of reaction time

[0055] First, furan dicarboxaldehyde (10 mmol) was added to a high pressure reactor, followed by Raney Ni (5 wt%) and THF (150 mL), and ammonia (0.5 MPa) and hydrogen 1.0 MPa were introduced. The reaction temperature range was 140° C., and the reaction time range was 0.5-24 h. After filtration and spin drying, furanyl amines were obtained.

[0056] Example 3: Preparation of novel furanylamine monomers with different structures

[0057] First, different furanyl aldehyde monomers A1-A15 (10 mmol) were added to a high-pressure reactor, and then RaneyNi (5 wt%) and THF (150 mL) were added, and ammonia (0.5 MPa) and hydrogen 1.0 MPa were introduced. The reaction temperature range was 140° C., and the reaction time range was 12 h. After filtering and spin drying, furanyl amine monomers B1-B15 were obtained.

[0058] The numbers and corresponding structures of furanyl aldehyde monomers are shown in Table 1 below.

[0059] Table 1

[0060]

[0061]

[0062] Table 2 Reaction conditions of Examples 1-3

[0063]

[0064]

[0065] Example 4: Preparation of amino resin based on furanylamine monomers - different furanylamine monomers

[0066] A 5 mol / L formaldehyde solution was added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) was added dropwise. When the sodium hydroxide solution was added, the temperature in the reactor was controlled at the first reaction temperature (25°C). When the pH value reached 9.0, the sodium hydroxide solution was stopped, and the temperature was kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time was continued for 30 minutes. Different furanylamine monomers B1-B15 (15 mol / L) were added to the reactor in batches, and the reaction was continued at this temperature for 60 minutes. Azoisobutyronitrile, a catalyst with a mass fraction of 0.5 wt%, was added to the reactor and stirred for 30 minutes. Then, an aldehyde solution was added to the reactor and stirred for 30 minutes. The reactor was heated to 45°C and reacted for 30 minutes. The reaction was continued to heat up at a rate of 2°C / min, so that the temperature in the reactor was stabilized at about 70°C and continued to react for 30 minutes to obtain a clear and transparent amino resin. After the reaction, the viscosity and peel strength tests were performed.

[0067] Example 5: Preparation of amino resin based on furanylamine monomers - different concentrations of furanylamine monomers

[0068] A 5 mol / L formaldehyde solution was added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) was added dropwise. When the sodium hydroxide solution was added, the temperature in the reactor was controlled at the first reaction temperature (25°C). When the pH value reached 9.0, the sodium hydroxide solution was stopped, and the temperature was kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time was continued for 30 minutes. Different concentrations of furanylamine monomers (1-25 mol / L) were added to the reactor in batches, and the reaction was continued at this temperature for 60 minutes. A catalyst azoisobutyronitrile with a mass fraction of 0.5 wt% was added to the reactor and stirred for 30 minutes. Then an aldehyde solution was added to the reactor and stirred for 30 minutes. The reactor was heated to 45°C and reacted for 30 minutes. The reaction was continued to heat up at a rate of 2°C / min, so that the temperature in the reactor was stabilized at about 70°C and continued to react for 30 minutes to obtain a clear and transparent amino resin. After the reaction, the viscosity and peel strength tests were performed.

[0069] Example 6: Preparation of amino resin based on furanylamine monomers - different aldehyde monomers

[0070] 5 mol / L of different aldehyde solutions (formaldehyde, acetaldehyde, succinaldehyde, 2,5-furandicarboxaldehyde, valeraldehyde, adipaldehyde, benzaldehyde, phenylpropionaldehyde, citral) were added to the reactor for stirring, and sodium hydroxide solution (1 mol / L) was added dropwise. When the sodium hydroxide solution was added, the temperature in the reactor was controlled at the first reaction temperature (25°C). When the pH value reached 9.0, the sodium hydroxide solution was stopped, and the temperature was kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time was continued for 30 minutes. Furanyl diamine with a molar mass of 1.5 mol was added to the reactor in batches, and the reaction was continued at this temperature for 60 minutes. Azoisobutyronitrile, a catalyst with a mass fraction of 0.5 wt%, was added to the reactor and stirred for 30 minutes. Aldehyde solution was added to the reactor and stirred for 30 minutes. The reactor was heated to 45°C for 30 minutes. The temperature of the reaction vessel was continued to be raised at a rate of 2°C / min, and the temperature in the reactor was stabilized at about 70°C and the reaction was continued for 30 minutes to obtain a clear and transparent amino resin. After the reaction was completed, the viscosity and peel strength tests were performed.

[0071] Example 7: Preparation of amino resin based on furanylamine monomers - different concentrations of aldehyde monomers

[0072] Add formaldehyde solution (0.5-20mol / L) to the reactor and stir, add sodium hydroxide solution (1mol / L) dropwise, and control the temperature in the reactor at the first reaction temperature (25°C) when adding sodium hydroxide solution. When the pH value reaches 9.0, stop adding sodium hydroxide solution, and keep the temperature constant at the first reaction temperature to continue the reaction, for example, continue the reaction time for 30min. Add furanyl diamine with a molar mass of 1.5mol to the reactor in batches, and continue the reaction at this temperature for 60min. Add 0.5wt% catalyst azoisobutyronitrile to the reactor and stir for 30min. Add aldehyde solution to the reactor and stir for 30min. Heat the reactor to 45°C and react for 30min. Continue to heat the reaction at a rate of 2°C / min, stabilize the temperature in the reactor at about 70°C, and continue the reaction for 30min to obtain a clear and transparent amino resin. After the reaction, viscosity and peel strength tests are performed.

[0073] Example 8: Preparation of amino resin based on furanylamine monomers - different alkaline solutions

[0074] A 5 mol / L formaldehyde solution was added to the reactor and stirred, and 1 mol / L different alkaline solutions (sodium hydroxide, potassium hydroxide, potassium bicarbonate, sodium carbonate, potassium tert-butoxide, ammonia water) were dripped in. When the sodium hydroxide solution was dripped, the temperature in the reactor was controlled at the first reaction temperature (25°C). When the pH value reached 9.0, the sodium hydroxide solution was stopped, and the temperature was kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time was continued for 30 minutes. Furanyl diamine with a molar mass of 1.5 mol was added to the reactor in batches, and the reaction was continued at this temperature for 60 minutes. Azoisobutyronitrile with a mass fraction of 0.5 wt% catalyst was added to the reactor and stirred for 30 minutes. Then, an aldehyde solution was added to the reactor and stirred for 30 minutes. The reactor was heated to 45°C and reacted for 30 minutes. The reaction was continued to heat up at a rate of 2°C / min, so that the temperature in the reactor was stabilized at about 70°C and continued to react for 30 minutes to obtain a clear and transparent amino resin. After the reaction, the viscosity and peel strength tests were performed.

[0075] Example 9: Preparation of amino resin based on furanylamine monomers - different concentrations of alkali solution

[0076] A 5 mol / L formaldehyde solution was added to the reactor and stirred, and different concentrations of sodium hydroxide solution (0.5-2 mol / L) were dripped in. When the sodium hydroxide solution was dripped, the temperature in the reactor was controlled at the first reaction temperature (25°C). When the pH value reached 9.0, the sodium hydroxide solution was stopped, and the temperature was kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time was continued for 30 minutes. Furanyl diamine with a molar mass of 1.5 mol was added to the reactor in batches, and the reaction was continued at this temperature for 60 minutes. Azoisobutyronitrile with a mass fraction of 0.5 wt% catalyst was added to the reactor and stirred for 30 minutes. Then, an aldehyde solution was added to the reactor and stirred for 30 minutes. The reactor was heated to 45°C and reacted for 30 minutes. The reaction was continued to heat up at a rate of 2°C / min, so that the temperature in the reactor was stabilized at about 70°C and continued to react for 30 minutes to obtain a clear and transparent amino resin. After the reaction, the viscosity and peel strength tests were performed.

[0077] Example 10: Preparation of amino resin based on furanylamine monomers - different pH values

[0078] A 5 mol / L formaldehyde solution was added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) was added dropwise. When the sodium hydroxide solution was added, the temperature in the reactor was controlled at the first reaction temperature (25°C). At different pH values ​​(8-11), the sodium hydroxide solution was stopped, and the temperature was kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time was continued for 30 minutes. A furanyl diamine with a molar mass of 1.5 mol was added to the reactor in batches, and the reaction was continued at this temperature for 60 minutes. A catalyst azoisobutyronitrile with a mass fraction of 0.5 wt% was added to the reactor and stirred for 30 minutes. An aldehyde solution was added to the reactor and stirred for 30 minutes. The reactor was heated to 45°C and reacted for 30 minutes. The reaction was continued to heat up at a rate of 2°C / min, so that the temperature in the reactor was stabilized at about 70°C and continued to react for 30 minutes to obtain a clear and transparent amino resin. After the reaction, the viscosity and peel strength tests were performed.

[0079] Example 11: Preparation of amino resin based on furanylamine monomers - different catalysts

[0080] A 5 mol / L formaldehyde solution is added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) is added dropwise. When the sodium hydroxide solution is added dropwise, the temperature in the reactor is controlled at the first reaction temperature (25°C). When the pH value reaches 9.0, the sodium hydroxide solution is stopped, and the temperature is kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time is continued for 30 minutes. A furanyl diamine with a molar mass of 1.5 mol is added to the reactor in batches, and the reaction is continued at this temperature for 60 minutes. 0.5 wt% of different catalysts (polyvinyl chloride, dibutyltin dilaurate, magnesium oxide, Pd-Fe, azoisobutyronitrile) are added to the reactor and stirred for 30 minutes. Then, an aldehyde solution is added to the reactor and stirred for 30 minutes. The reactor is heated to 45°C and reacted for 30 minutes. The reaction is continued to be heated at a rate of 2°C / min, so that the temperature in the reactor is stabilized at about 70°C and the reaction is continued for 30 minutes to obtain a clear and transparent amino resin. After the reaction is completed, the viscosity and peel strength tests are performed.

[0081] Example 12: Preparation of amino resin based on furanylamine monomers - different catalyst concentrations

[0082] A 5 mol / L formaldehyde solution is added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) is added dropwise. When the sodium hydroxide solution is added dropwise, the temperature in the reactor is controlled at the first reaction temperature (25°C). When the pH value reaches 9.0, the sodium hydroxide solution is stopped, and the temperature is kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time is continued for 30 minutes. Furanyl diamine with a molar mass of 1.5 mol is added to the reactor in batches, and the reaction is continued at this temperature for 60 minutes. Different concentrations of azoisobutyronitrile (0.01-5wt%) are added to the reactor and stirred for 30 minutes. Then, an aldehyde solution is added to the reactor and stirred for 30 minutes. The reactor is heated to 45°C and reacted for 30 minutes. The reaction is continued to be heated at a rate of 2°C / min, so that the temperature in the reactor is stabilized at about 70°C and the reaction is continued for 30 minutes to obtain a clear and transparent amino resin. After the reaction is completed, the viscosity and peel strength tests are performed.

[0083] Example 13: Preparation of amino resin based on furanylamine monomers - different heating rates

[0084] A 5 mol / L formaldehyde solution is added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) is added dropwise. When the sodium hydroxide solution is added dropwise, the temperature in the reactor is controlled at the first reaction temperature (25°C). When the pH value reaches 9.0, the sodium hydroxide solution is stopped, and the temperature is kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time is continued for 30 minutes. A furanyl diamine with a molar mass of 1.5 mol is added to the reactor in batches, and the reaction is continued at this temperature for 60 minutes. A catalyst azoisobutyronitrile with a mass fraction of 0.5wt% is added to the reactor and stirred for 30 minutes. Then an aldehyde solution is added to the reactor and stirred for 30 minutes. The reactor is heated to 30°C and reacted for 30 minutes. The reaction is continued to be heated at a rate of 0.5-5°C / min, so that the temperature in the reactor is stabilized at about 70°C and the reaction is continued for 30 minutes to obtain a clear and transparent amino resin. After the reaction is completed, the viscosity and peel strength tests are performed.

[0085] Example 14: Preparation of amino resin based on furanylamine monomers - different reaction temperatures

[0086] A 5 mol / L formaldehyde solution was added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) was added dropwise. When the sodium hydroxide solution was added, the temperature in the reactor was controlled at the first reaction temperature (20-30°C). When the pH value reached 9.0, the sodium hydroxide solution was stopped, and the temperature was kept constant at the first reaction temperature to allow the reaction to continue for 30 minutes. Furanyl diamine with a molar mass of 1.5 mol was added to the reactor in batches, and the reaction was continued at this temperature for 60 minutes. A catalyst azoisobutyronitrile with a mass fraction of 0.5wt% was added to the reactor and stirred for 30 minutes. An aldehyde solution was added to the reactor and stirred for 30 minutes. The reactor was heated to the second reaction temperature (30-50°C) and reacted for 30 minutes. The reaction was continued to heat up (third reaction temperature 50-90°C), the heating rate was 0.5-5°C / min, and the reaction was continued for 30 minutes to obtain a clear and transparent amino resin. After the reaction, the viscosity and peel strength tests were performed.

[0087] Comparative Example 1: Preparation of amino resin

[0088] A 5 mol / L formaldehyde solution is added to the reactor and stirred, and a sodium hydroxide solution (1 mol / L) is added dropwise. When the sodium hydroxide solution is added dropwise, the temperature in the reactor is controlled at the first reaction temperature (25°C). When the pH value reaches 9.0, the sodium hydroxide solution is stopped, and the temperature is kept constant at the first reaction temperature to allow the reaction to continue, for example, the reaction time is continued for 30 minutes. 1.5 mol of melamine and benzoguanamine are added to the reactor in batches, and the reaction is continued at this temperature for 60 minutes. 2 wt% azoisobutyronitrile is added to the reactor and stirred for 30 minutes. Formaldehyde solution is then added to the reactor and stirred for 30 minutes. The reactor is heated to 30°C and reacted for 30 minutes. The reaction is continued to be heated at a rate of 2°C / min, so that the temperature in the reactor is stabilized at about 70°C and the reaction is continued for 30 minutes to obtain a clear and transparent amino resin. After the reaction is completed, the viscosity and peel strength tests are performed.

[0089] Table 3 Data of Examples 4-14 and Comparative Example 1

[0090]

[0091]

[0092] The peel strengths of Comparative Examples 51 (melamine) and 52 (benzoguanamine) are only 22.85 MPa and 34.75 MPa, which are significantly lower than those of furanylamines (such as 49.23 MPa of B2). This is mainly because the rigid conjugated structure of the furan ring can enhance the spatial stability of the resin cross-linked network, while the rigidity of the six-membered ring of traditional melamine is relatively low and the flexibility of the molecular chain is too high; in addition, the active amino sites of furanylamine are more likely to undergo polycondensation reactions with aldehydes to form a dense three-dimensional network structure. B2 (49.23 MPa) has the best performance among similar amines, and it is speculated that its substituents (such as functional groups on the furan ring) are mainly because it introduces hydrophobic groups (such as alkyl chains) to reduce water molecule penetration and improve interfacial adhesion.

[0093] The peel strength of the material shows a trend of increasing first and then stabilizing as the concentration of amine increases. The optimal concentration is 15mmol / L. Too high a concentration may lead to excessive entanglement of the molecular chains and reduce the mobility of the chain segments; too low a concentration may result in insufficient crosslinking points. In addition, the peel strength of AIBN (azoisobutyronitrile) reaches 49.23MPa at 0.5wt%, which is better than PVC (48.43MPa) and MgO (44.77MPa). This is mainly because AIBN, as a free radical initiator, decomposes at low temperature (25-45℃) to produce free radicals, promoting the growth of the prepolymer chain; while metal catalysts (such as Pd-Fe) will trigger side reactions and destroy the uniformity of crosslinking.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an amino resin based on furanylamine monomers, characterized in that The following steps are involved: Step 1: adding an alkaline solution to the aldehyde monomer solution to adjust the pH value of the system, and keeping the temperature at the first reaction temperature for reaction; Step 2: After the heat preservation reaction in the first temperature range is completed, furanylamine monomers and catalysts are added to the system in batches and reacted under stirring; Step 3: adding the aldehyde monomer solution to the system again, and controlling the system to react at a second reaction temperature; Step 4: Raise the system temperature to the third reaction temperature while stirring. When the preset viscosity value is reached, the reaction is completed to obtain a clear and transparent amino resin; The aldehyde monomer is selected from one or a mixture of two of formaldehyde, acetaldehyde, succinaldehyde, 2,5-furandicarboxaldehyde, valeraldehyde, adipaldehyde, benzaldehyde, phenylpropionaldehyde, and citral; The furanylamine monomer is selected from one or a mixture of monofuranylamine monomers, bisfuranylamine monomers, and polyfuranylamine monomers; The monofuranylamine monomer is selected from the compounds of the following structures: The bisfuranylamine monomer is selected from the compounds of the following structures: Wherein X is selected from *-(CH2) n -*、 The polyfuranylamine monomer is selected from the compounds of the following structures: in 2. The preparation method according to claim 1, characterized in that: The aldehyde monomer is formaldehyde and / or 2,5-furandicarboxaldehyde.

3. The preparation method according to claim 1, characterized in that: In step 1, the pH value of the system is adjusted to 8-11 using the alkaline solution.

4. The preparation method according to claim 1, characterized in that: In step 1, the first reaction temperature is 20-30°C.

5. The preparation method according to claim 1, characterized in that: In step 3, the second reaction temperature is 30-50°C.

6. The preparation method according to claim 1, characterized in that: In step 4, the third reaction temperature is 50-90°C.

7. The preparation method according to claim 1, characterized in that: In step 4, the preset viscosity value is 5000-500000 cP.

8. The preparation method according to claim 1, characterized in that: The mass of the aldehyde monomer added in step 1 is twice the mass of the aldehyde monomer added in step 3; the ratio of the total mass of the aldehyde monomer added to the reaction system to the mass of the furanylamine monomer is 1:1 to 3:

1.

9. Use of the amino resin prepared by the preparation method according to any one of claims 1 to 8 in the preparation of an adhesive.

10. The use according to claim 9, characterized in that: The adhesive is a metal adhesive.

Images