High-bonding-strength bio-based epoxy resin and synthesis method thereof

Abstract

According to the high-bonding-strength bio-based epoxy resin, furan rings, phosphate groups, silane groups and isocyanurate rings are grafted to epoxy resin molecules, the furan rings are beneficial to improving the flexibility of the epoxy resin and the adhesive force of the epoxy resin to a base material, and the phosphate groups are beneficial to greatly improving the adhesive force of the epoxy resin to the base material, especially metal; the silane group is beneficial to greatly improving the high-temperature and high-humidity resistance of the epoxy resin, and the tripolymer isocyanurate cyclic structure can greatly improve the heat resistance of the epoxy resin. The resin is excellent in comprehensive performance and storage stability.

Description

Technical Field

[0001] The invention relates to a bio-based epoxy resin with high bonding strength and a synthesis method thereof, and belongs to the field of polymer adhesives. Background Art

[0002] As an important type of thermosetting polymer adhesive material, epoxy adhesives have the characteristics of low curing shrinkage, high bonding strength, low residual stress, high bulk strength and modulus, and are widely used in composite materials, electronic packaging, automotive and architectural coatings and other fields. Due to the disadvantages of conventional epoxy adhesives such as high hardness, poor toughness, poor mechanical and temperature shock resistance after curing, they are limited in practical applications. For example, in the application test of body structure bonding, not only is the adhesive required to have high bonding strength to the substrate, but the failure mode after aging must be the destruction of the adhesive layer itself, so as to ensure its safety during service. Conventional epoxy adhesives often meet the bonding strength requirements, but the failure mode after aging is often the destruction of the interface between the adhesive layer and the substrate, which reduces safety. Epoxy resin, as the main component of epoxy structural adhesives, plays a vital role and influences its performance. Summary of the invention

[0003] In order to address the deficiencies of the prior art, the present invention provides a bio-based epoxy resin with high bonding strength and a synthesis method thereof. The product prepared therefrom has high initial bonding strength, excellent resistance to temperature shock, high temperature and high humidity, and dry heat, and can meet the requirements of structural bonding operability, reliability, and strength.

[0004] The technical solution of the present invention to solve the above problems is as follows: A method for synthesizing a bio-based epoxy resin with high bonding strength comprises the following steps: Step 1: react epoxy resin and bio-based furandicarboxylic acid (FDCA) at a molar ratio of 2-2.2:1 under the action of catalyst a at 80-120°C until the acid value is ≤0.2mgKOH / g to obtain prepolymer A; Step 2: reacting aminosilane and diisocyanate trimer in equal molar ratio at room temperature to 60°C until the NCO group reaches the designed value, then adding aminophosphoric acid ester and reacting at room temperature to 60°C until the NCO group reaches the designed value to obtain prepolymer B; The third step is to add prepolymer A into prepolymer B, and react at room temperature to 90°C under the action of catalyst b until the NCO group disappears.

[0005] Furthermore, the epoxy resin refers to a substance containing at least two epoxy functional groups in its molecular structure, preferably a structure containing a glycidyl ether group.

[0006] Furthermore, the catalyst a refers to a catalyst that can effectively catalyze the reaction of epoxy groups and carboxyl groups, including triphenylphosphine, tetrabutylammonium bromide, dimethylaniline, N, N-dimethylbenzylamine, triethylbenzyl ammonium chloride or triethylamine, and its added amount is one thousandth to one hundredth of the total mass of the prepolymer A, preferably triphenylphosphine.

[0007] Furthermore, the aminosilane refers to a structure containing a primary or secondary amine group on the molecule and a silicon methoxy group or a silicon ethoxy group, including N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and di(γ-trimethoxysilylpropyl)amine.

[0008] Furthermore, the diisocyanate trimer includes HDI trimer and IPDI trimer, preferably HDI trimer.

[0009] Furthermore, the amino phosphoroester refers to a structure containing a primary or secondary amino group and a phosphate group in the molecule, including aminomethylphosphonic acid, (1-aminobutyl)phosphonic acid, (1-aminooctyl)phosphonic acid, and 4-aminobutane-1-phosphonic acid.

[0010] Furthermore, the catalyst b comprises an organic tin, bismuth, zinc or zirconium catalyst, preferably an organic bismuth catalyst.

[0011] The beneficial effects of adopting this technical solution are as follows: this technical solution grafts furan ring, phosphoric acid group, silane group and isocyanurate ring onto epoxy resin molecules, furan ring is conducive to improving the flexibility of epoxy resin and adhesion to substrate, phosphoric acid group is conducive to greatly improving the adhesion between epoxy resin and substrate, especially metal, silane group is conducive to greatly improving the high temperature and high humidity resistance of epoxy resin, and trimer isocyanurate ring structure can greatly improve the heat resistance of epoxy resin. Compared with simple physical mixing of components and commercially available resins, this resin has excellent comprehensive performance and excellent storage stability. DETAILED DESCRIPTION

[0012] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0013] Example 1 514 g of 1,4-cyclohexanedimethanol diglycidyl ether, 156.1 g of bio-based FDCA, and 2 g of triphenylphosphine were added to the reactor in sequence, and the mixture was stirred and reacted at 100-110° C. until the acid value was ≤0.2 mgKOH / g, and prepolymer A was obtained by discharging the material; 504.58 g of HDI trimer and 221.4 g of 3-aminopropyltriethoxysilane were added to the reactor in sequence, and the mixture was stirred and reacted at 40° C. for 0.5-1 h until the NCO group content was ≤11.57%, 209.22 g of (1-aminooctyl)phosphoric acid was continuously added to the reactor, and the mixture was stirred and reacted at 40° C. until the NCO group content was ≤4.5%, and prepolymer B was obtained; 670.1 g of prepolymer A and 0.8 g of BiCAT Z catalyst from Leading Chemicals of the United States were continuously added to the reactor, and the mixture was reacted at 40-60° C. until the NCO group disappeared, and a high bonding strength bio-based epoxy resin A was obtained.

[0014] At room temperature, 100 parts of high bonding strength bio-based epoxy resin A, 20 parts of neopentyl glycol diglycidyl ether, 30 parts of trimethylolpropane triglycidyl ether, and 10 parts of AEROSIL R202 hydrophobic fumed silica from Evonik Degussa are added to a stirring tank by weight, stirred evenly, and vacuumed for degassing; 15 parts of OMICURE DDA from Huntsman and 4 parts of OMICURE U-410M are sequentially added to the stirring tank, stirred evenly, vacuumed for degassing, and the materials are discharged for standby use.

[0015] Example 2 Add 605g of trimethylolpropane triglycidyl ether, 156.1g of bio-based FDCA, and 2.3g of triphenylphosphine to the reactor in sequence, stir and react at 100-110°C until the acid value is ≤0.2mgKOH / g, and discharge to obtain prepolymer A; add 504.58g of HDI trimer and 179.3g of 3-aminopropyltrimethoxysilane to the reactor in sequence, stir and react at 40°C until the NCO group content is ≤12.28%, continue to add 153.11g of (1-aminobutyl)phosphonic acid to the reactor, stir and react at 40°C for 0.5-1h until the NCO group content is ≤5%, obtain prepolymer B, continue to add 763g of prepolymer A and 0.8g of BiCAT Z catalyst from Leading Chemicals of the United States to the reactor, react at 40-60°C until the NCO group disappears, and obtain high bonding strength bio-based epoxy resin B.

[0016] At room temperature, 100 parts of high bonding strength bio-based epoxy resin B, 30 parts of neopentyl glycol diglycidyl ether, 20 parts of trimethylolpropane triglycidyl ether, and 10 parts of AEROSIL R202 hydrophobic fumed silica from Evonik Degussa are added to a stirring tank by weight, stirred evenly, and vacuumed for degassing; 15 parts of OMICURE DDA from Huntsman and 4 parts of OMICURE U-410M are sequentially added to the stirring tank, stirred evenly, vacuumed for degassing, and the materials are discharged for standby use.

[0017] Example 3 3000g of castor oil triglycidyl ether XY966 of Anhui Xinyuan Technology Co., Ltd., 156.1g of bio-based FDCA, and 9.5g of triphenylphosphine were added to the reactor in sequence, and the mixture was stirred and reacted at 100-110°C until the acid value was ≤0.2mgKOH / g, and prepolymer A was obtained by discharging the material; 504.58g of HDI trimer and 255.4g of N-phenyl-3-aminopropyltrimethoxysilane were added to the reactor in sequence, and the mixture was stirred and reacted at 40°C until the NCO group content was ≤11.52%, and 153.12g of 4-aminobutane-1-phosphoric acid was continuously added to the reactor, and the mixture was stirred and reacted at 40°C for 0.5-1h until the NCO group content was ≤5%, to obtain prepolymer B, and 3165.6g of prepolymer A and 2g of BiCAT Z catalyst of Leading Chemicals of the United States were continuously added to the reactor, and the mixture was reacted at 40-60°C until the NCO group disappeared, to obtain high bonding strength bio-based epoxy resin C.

[0018] At room temperature, 100 parts of high bonding strength bio-based epoxy resin C, 25 parts of neopentyl glycol diglycidyl ether, 25 parts of trimethylolpropane triglycidyl ether, and 10 parts of AEROSIL R202 hydrophobic fumed silica from Evonik Degussa are added to a stirring tank by weight, stirred evenly, and vacuumed for degassing; 13 parts of OMICURE DDA from Huntsman and 4 parts of OMICURE U-410M are sequentially added to the stirring tank, stirred evenly, vacuumed for degassing, and the materials are discharged for standby use.

[0019] Comparative Example 1 At room temperature, 100 parts of bisphenol A flexible epoxy resin EXA-4850-150, 20 parts of neopentyl glycol diglycidyl ether, 30 parts of trimethylolpropane triglycidyl ether, 5 parts of 3-aminopropyl triethoxysilane, and 10 parts of AEROSIL R202 hydrophobic fumed silica from Evonik Degussa are taken by weight, added into a stirring kettle, stirred evenly, and vacuumed for degassing; 15 parts of OMICURE DDA from Huntsman and 4 parts of OMICURE U-410M are sequentially added into the stirring kettle, stirred evenly, vacuumed for degassing, and the materials are discharged for standby use.

[0020] Comparative Example 2 At room temperature, 100 parts of HP-4032SS epoxy with high hardness containing naphthalene ring, 40 parts of neopentyl glycol diglycidyl ether, 10 parts of trimethylolpropane triglycidyl ether, 5 parts of 3-aminopropyl triethoxysilane, and 10 parts of AEROSIL R202 hydrophobic fumed silica from Evonik Degussa are added to a stirring tank by weight, stirred evenly, and vacuumed for degassing; 15 parts of OMICURE DDA from Huntsman and 4 parts of OMICURE U-410M are sequentially added to the stirring tank, stirred evenly, vacuumed for degassing, and the material is discharged for standby use.

[0021] The properties of the epoxy resins of the present invention were tested by the following tests.

[0022] The bonding substrate is 3003Al, the bonding area is 12.5mm×25mm, the adhesive layer thickness is 0.5mm, the curing process is 150℃20min, and the test speed is 50mm / min.

[0023] 1. Initial shear strength test.

[0024] 2. High and low temperature impact test: The sample is placed in (-40℃ / 30min-85℃ / 30min) for 200 cycles, and then placed at room temperature for 24h.

[0025] 3. High temperature and high humidity test: Place the sample at 85°C, 85%RH for 1000 hours, and then place it at room temperature for 24 hours.

[0026] 4. Dry heat test: ① Place the sample at 120℃ for 300h and test immediately.

[0027] ② Place the sample at 120℃ for 300h, then test it at room temperature for 24h.

[0028] The test results are shown in Table 1

[0029] Table 1 Comparative test results of the embodiment and the comparative example

[0030] From the above results, it can be seen that compared with the commercially available resins, the high bonding strength bio-based epoxy resin of the present invention has high bonding strength, good resistance to high temperature and humidity, high and low temperature impact and dry heat performance, and the failure mode is the destruction of the adhesive layer itself, and has higher reliability.

[0031] 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, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for synthesizing a bio-based epoxy resin with high bonding strength, comprising the following steps: Step 1: react epoxy resin and bio-based furandicarboxylic acid in a molar ratio of 2-2.1:1 under the action of catalyst a at 80-120°C until the acid value is ≤0.2mgKOH / g to obtain prepolymer A; Step 2: reacting aminosilane and diisocyanate trimer in equal molar ratio at room temperature to 60°C until the NCO group reaches the designed value, then adding aminophosphoric acid ester and reacting at room temperature to 60°C until the NCO group reaches the designed value to obtain prepolymer B; The third step is to add prepolymer A into prepolymer B, and react at room temperature to 90°C under the action of catalyst b until the NCO group disappears.

2. The method for synthesizing a bio-based epoxy resin with high bonding strength according to claim 1, characterized in that: The epoxy resin refers to a substance containing at least two epoxy functional groups in its molecular structure.

3. The method for synthesizing a bio-based epoxy resin with high bonding strength according to claim 1, characterized in that: The catalyst a comprises one of triphenylphosphine, tetrabutylammonium bromide, dimethylaniline, N,N-dimethylbenzylamine, triethylbenzyl ammonium chloride or triethylamine, and its added amount is 1 / 1000 to 1 / 100 of the total mass of the prepolymer A.

4. The method for synthesizing a bio-based epoxy resin with high bonding strength according to claim 1, characterized in that: The aminosilane includes one of N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and di(γ-trimethoxysilylpropyl)amine.

5. The method for synthesizing a bio-based epoxy resin with high bonding strength according to claim 1, characterized in that: The diisocyanate trimer includes HDI trimer and IPDI trimer.

6. The method for synthesizing a bio-based epoxy resin with high bonding strength according to claim 1, characterized in that: The amino phosphoric acid ester includes one of aminomethylphosphonic acid, (1-aminobutyl)phosphonic acid, (1-aminooctyl)phosphonic acid, and 4-aminobutane-1-phosphonic acid.

7. The method for synthesizing a bio-based epoxy resin with high bonding strength according to claim 1, characterized in that: The catalyst b includes an organic tin, bismuth, zinc or zirconium catalyst.

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