Epoxy resin cured product and preparation method thereof

Abstract

The invention discloses a cured epoxy resin and a preparation method thereof. The cured epoxy resin is obtained by curing an epoxy resin matrix, an epoxy resin toughening modifier and a curing agent. Wherein the epoxy resin toughening modifier is a polyether ester amide multi-block copolymer, comprises three block components, namely aliphatic polyether, polyester and polyamide, and can be dissolved in an epoxy resin matrix at normal temperature or under heating to prepare corresponding modified epoxy resin, and the modified epoxy resin is separated out and subjected to microphase separation when the epoxy resin is cured. The microphase separation scale is very small, so that the transparency of the cured epoxy resin is relatively good. After the epoxy resin toughening modifier is added, the toughness, the impact strength and the tensile strength of an epoxy resin cured product are obviously improved, the problems of insufficient toughness, high brittleness and the like of the epoxy resin cured product and a composite material thereof are effectively improved, and high-transparency epoxy resin can be prepared.

Description

Technical Field

[0001] The invention relates to the field of epoxy resins, in particular to an epoxy resin cured product and a preparation method thereof. Background Art

[0002] Epoxy resin is the most widely used thermosetting material due to its excellent mechanical and chemical stability, heat resistance, corrosion resistance, electrical insulation and bonding properties. It is widely used in anti-corrosion coatings, adhesives, electronic packaging materials, electrical insulation materials and high-performance composite materials. However, the epoxy resin structure after curing is highly cross-linked, and has disadvantages such as poor impact resistance, poor fracture toughness and poor fatigue resistance, which seriously limits the application of epoxy resin in some important fields such as advanced composite materials, structural adhesives, and ultra-low temperature tough materials. Therefore, toughening modification of epoxy resin has become a hot research topic.

[0003] At present, according to the toughening mechanism, the toughening system of epoxy resin can be divided into homogeneous toughening system and heterogeneous toughening system. The homogeneous toughening system is mainly achieved by introducing flexible segments into the epoxy resin. This method not only has certain difficulties in the design and synthesis of raw materials, but also significantly reduces the strength of the epoxy resin. The heterogeneous toughening system involves phase separation between the modifier and the epoxy resin matrix, which is usually a multiphase structure with a phase structure size of submicron or micron order.

[0004] Block copolymers can contain both epoxy resin miscible blocks and immiscible blocks, providing a new method for toughening epoxy resins. By adjusting the composition and structure of the block copolymers, significant toughening effects can be achieved.

[0005] At present, there are many studies on diblock and triblock copolymers as epoxy resin toughening agents. For example, CN115160515A discloses the use of an amphiphilic liquid crystal block copolymer in an epoxy resin toughening agent, wherein the amphiphilic liquid crystal block copolymer is obtained by atom transfer radical polymerization or reversible addition-fragmentation chain transfer solution polymerization of polyethylene glycol methyl ether methyl methacrylate or 2-(dimethylamino)ethyl methacrylate with biphenyl liquid crystal monomers or diphenylethylene liquid crystal monomers. Although this toughening system has a good toughening effect on epoxy resin, a large amount of organic solvents are consumed in its synthesis process, the preparation cost is high, and it is not environmentally friendly, so it is difficult to be used for toughening epoxy resin in actual production.

[0006] CN102348757A discloses a heat-curable composition containing a combination of an amphiphilic block copolymer and a polyol and a thermosetting product thereof. The epoxy resin toughening agent used is concentrated on an amphiphilic polyether block copolymer having an epoxy resin miscible block and an immiscible block, which has a good toughening effect on epoxy resin. However, the invention does not explain the toughening effect of the multi-block copolymer in epoxy resin. Moreover, the phase separation scale of the two-block copolymer is large, and the toughening modification effect on epoxy resin is limited.

[0007] Compared with diblock copolymers, multiblock copolymers have better toughening and modification effects because their blocks can shuttle between multiple micro-regions. At the same time, since the microphase separation scale formed is smaller and the light scattering is weaker, the epoxy resin cured product formed by it has high transparency.

[0008] Based on the above analysis, there is an urgent need to develop a multi-block copolymer as an epoxy resin toughening modifier to be used in the toughening of epoxy resin to achieve a significant improvement in its tensile strength and impact strength, and to achieve high transparency. Summary of the invention

[0009] To solve the above technical problems, the present invention provides an epoxy resin cured product and a preparation method thereof, wherein epoxy resin is toughened and modified by a multi-block copolymer, and the epoxy resin toughening modifier is a polyether ester amide multi-block copolymer composed of aliphatic polyether, polyester and polyamide. Wherein the polyether and polyester blocks have good solubility in the epoxy resin matrix. The multi-block copolymer has a certain compatibility in the epoxy resin matrix and can be dissolved in the epoxy resin matrix at room temperature or under heating to obtain a corresponding modified epoxy resin matrix. When the epoxy resin is cured, the multi-block copolymer precipitates and microphase separation occurs. Since the scale of microphase separation in the system is very small, a high-strength and tough epoxy resin cured product with good transparency can be prepared. After adding the epoxy resin toughening modifier of the present invention, under the condition that its transparency is not greatly affected, the toughness, impact strength and tensile strength of the epoxy resin cured product are significantly improved.

[0010] The present invention is achieved through the following technical solutions: The first object of the present invention is to provide an epoxy resin cured product, wherein the epoxy resin cured product is obtained by curing a modified epoxy resin, wherein the modified epoxy resin comprises the following components: an epoxy resin matrix, an epoxy resin toughening modifier and a curing agent.

[0011] In one embodiment of the present invention, the epoxy resin toughening modifier is a polyetheresteramide multi-block copolymer; the polyetheresteramide multi-block copolymer consists of three blocks of aliphatic polyether, aliphatic polyester and aliphatic polyamide.

[0012] The content of the aliphatic polyether is 60 wt %~90 wt %; the content of the aliphatic polyester is 10 wt %~30 wt %; the content of the aliphatic polyamide is 1 wt %~12 wt %, and the sum of the contents of each component is 100 wt %.

[0013] In one embodiment of the present invention, the epoxy resin matrix is ​​selected from bisphenol A type epoxy resin with an epoxy value of 0.1 to 0.6, including but not limited to one or more of E-12, E-44, E-51 and BE-188EL.

[0014] In one embodiment of the present invention, the curing agent is an amine curing agent; the amine curing agent is selected from one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and isophoronediamine.

[0015] In one embodiment of the present invention, the chemical structural formula of the polyetheresteramide multi-block copolymer is as follows: ; Wherein, a is any integer from 2 to 6; b is any integer from 2 to 11; c is any integer from 2 to 4; d is any integer from 5 to 12; e is any integer from 4 to 68; f, g, and h are determined by the contents of aliphatic polyester, aliphatic polyether, and aliphatic polyamide, respectively; the block content of the aliphatic polyether is 60 wt% to 90 wt%; the content of the aliphatic polyester block is 10 wt% to 30 wt%; the content of the aliphatic polyamide block is 1 wt% to 12 wt%, and the sum of the contents of each component is 100 wt%; the number average molecular weight of the multi-block copolymer is 6000 g / mol to 50000 g / mol.

[0016] In one example of the present invention, the aliphatic polyether is preferably one or more selected from polyethylene oxide and polytetrahydrofuran; the number average molecular weight of the polyether block is 200 g / mol to 3000 g / mol.

[0017] In one embodiment of the present invention, the aliphatic polyester is a polyaliphatic diacid diol ester, preferably one or more selected from polyethylene adipate, polybutylene succinate, polyethylene tridecanoate and polyethylene dodecanoate.

[0018] In one embodiment of the present invention, the aliphatic polyamide is preferably one or more selected from nylon 1013, nylon 613, nylon 1213, nylon 104 and nylon 1012.

[0019] In one embodiment of the present invention, the mass ratio of the epoxy resin matrix to the epoxy resin toughening modifier is 200:1~10:1; the molar ratio of the amount of the curing agent to the epoxy value of the epoxy resin matrix is ​​2:1~1:2, preferably 1:1.

[0020] The second object of the present invention is to provide a method for preparing a modified epoxy resin cured product, comprising the following steps: mixing an epoxy resin matrix with an epoxy resin toughening modifier, heating to 60°C to 150°C, stirring for 20 min to 1 h, mixing uniformly, and cooling to room temperature; adding a curing agent and mixing, and heating and curing in a mold after mixing uniformly to obtain the epoxy resin cured product.

[0021] The above technical solution of the present invention has the following advantages compared with the prior art: 1. The present invention provides an epoxy resin cured product and a preparation method thereof. The epoxy resin toughening modifier proposed in the present invention is a polyetheresteramide multi-block copolymer. The polyether and polyester blocks serve as flexible blocks and have good compatibility with the epoxy resin matrix, and can provide good flexibility and impact strength; while the polyamide block has poor compatibility with the epoxy resin matrix. Therefore, the toughening modifier of the present invention can not only maintain good compatibility in the epoxy resin matrix, effectively improve its dispersion effect in the epoxy resin matrix, but also precipitate and undergo microphase separation when the epoxy resin is cured, thereby achieving a significant improvement in the toughness, impact strength and tensile strength of the epoxy resin cured product.

[0022] 2. After the epoxy resin toughening modifier of the present invention acts on the epoxy resin, the transparency of the epoxy resin cured product is better due to the small scale of microphase separation in the system, and the transparency of the epoxy resin will not be affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 is a stress-strain curve diagram of the epoxy resin cured product in Example 1 of the present invention; Figure 2 is a stress-strain curve diagram of the epoxy resin cured product in Example 3 of the present invention; Figure 3 is a stress-strain curve diagram of the epoxy resin cured product in Example 4 of the present invention; Figure 4 It is a stress-strain curve diagram of the epoxy resin cured product in Comparative Example 1 of the present invention; Figure 5 This is a transparency comparison diagram of epoxy resin cured casting specimens in an embodiment of the present invention; Figure 6 This is a comparison chart of the impact resistance and tensile properties of the epoxy resin cured material in the embodiment of the present invention and the epoxy resin cured material in Comparative Example 1. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0025] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0026] The CAS number information table of the organic reagents used in the present invention is as follows: Table 1

[0027] In the following embodiments of the present invention, the polyetheresteramide multi-block copolymer is prepared by ring-opening-condensation cascade polymerization. The specific preparation method is referred to patent CN116425983B - A high-impact polyetheresteramide thermoplastic elastomer and its preparation method.

[0028] Among them, the polyetheresteramide multi-block copolymer mBCP-1 was prepared by mixing musk T (10.0 g), polyethylene glycol (20.0 g, molecular weight 2000 g / mol), 1,10-decanediamine (0.6 g) and 15.0 μL tetrabutyl titanate, nitrogen gas, mechanical stirring, and reaction at 220 °C for 60 min. The quantitative nuclear magnetic hydrogen spectrum test of mBCP-1 showed that the polyester block was polyethylene tridecane dioate (PEB) with a content of 21%; the polyether block was polyethylene oxide (PEO) with a content of 73%; the polyamide block was nylon 1013 with a content of 6%, and the molecular weight of mBCP-1 was 6.5 kg / mol.

[0029] The polyetheresteramide multi-block copolymer mBCP-2 was prepared by mixing musk T (10.0 g), polyethylene glycol (20.0 g, molecular weight 2000 g / mol), 1,10-decanediamine (0.6 g) and 15.0 μL tetrabutyl titanate, passing nitrogen, mechanical stirring, heating to 240 °C, and vacuum reaction for 60 min. The quantitative H-NMR test of mBCP-2 showed that the polyester block was polyethylene tridecane dioate (PEB) with a content of 25%; the polyether block was polyethylene oxide (PEO) with a content of 72%; the polyamide block was nylon 1013 with a content of 3%, and the molecular weight of mBCP-2 was 21.1 kg / mol.

[0030] The preparation method of polyetheresteramide multi-block copolymer mBCP-3 is similar to that of mBCP-2, with the only difference being that 1,6-hexanediamine is used instead of 1,10-decanediamine. Quantitative H-NMR spectrum test of mBCP-3 shows that the polyester block is polyethylene tridecanediol (PEB) with a content of 16%; the polyether block is polyethylene oxide (PEO) with a content of 80%; the polyamide block is nylon 613 with a content of 4%. The molecular weight of mBCP-3 is 28.8 kg / mol.

[0031] The preparation method of polyetheresteramide multi-block copolymer mBCP-4 is similar to that of mBCP-1, except that it is prepared by mixing musk T (10.0 g), polyethylene glycol (30.0 g, molecular weight 3000 g / mol), 1,10-decanediamine (0.8 g) and 20.0 μL tetrabutyl titanate. Quantitative H-NMR spectrum test of mBCP-4 shows that the polyester block is polyethylene tridecane dioate (PEB) with a content of 13%; the polyether block is polyethylene oxide (PEO) with a content of 83%; the polyamide block is nylon 1013 with a content of 4%, and the molecular weight of mBCP-4 is 11.7 kg / mol.

[0032] The preparation method of polyetheresteramide multi-block copolymer mBCP-5 is similar to that of mBCP-1, except that it is prepared by mixing musk T (10.0 g), polyethylene glycol (20.0 g, molecular weight 600 g / mol), 1,12-dodecanediamine (0.6 g) and 15.0 μL tetrabutyl titanate. Quantitative H-NMR spectrum test of mBCP-5 shows that the polyester block is polyethylene tridecane dioate (PEB) with a content of 22%; the polyether block is polyethylene oxide (PEO) with a content of 75%; the polyamide block is nylon 1213 with a content of 3%, and the molecular weight of mBCP-5 is 15.9 kg / mol.

[0033] The preparation method of polyetheresteramide multi-block copolymer mBCP-6 is similar to that of mBCP-1, except that the musk T is replaced by an equal amount of cyclic oligomeric butylene succinate. The quantitative H-NMR spectrum test of mBCP-6 shows that the polyester block is polybutylene succinate (PBS) with a content of 27%, the polyether block is polyethylene oxide (PEO) with a content of 70%, and the polyamide block is nylon 104 with a content of 3%. The intrinsic viscosity of mBCP-6 is 0.32 dL / g.

[0034] The preparation method of polyetheresteramide multi-block copolymer mBCP-7 is similar to that of mBCP-1, except that it is prepared by mixing musk T (10.0 g), polyethylene glycol (20.0 g, molecular weight 2000 g / mol), 1,10-decanediamine (1.5 g) and 15.0 μL tetrabutyl titanate. Quantitative H-NMR spectrum test of mBCP-7 shows that the polyester block is polyethylene tridecane dioate (PEB) with a content of 18%; the polyether block is polyethylene oxide (PEO) with a content of 71%; the polyamide block is nylon 1013 with a content of 11%, and the molecular weight of mBCP-7 is 6.1 kg / mol.

[0035] The preparation method of polyetheresteramide multi-block copolymer mBCP-8 is similar to that of mBCP-1, except that it is prepared by mixing zen musk (10.0 g), polytetramethylene glycol (20.0 g, molecular weight 1000 g / mol), 1,10-decanediamine (0.6 g) and 15.0 μL tetrabutyl titanate. Quantitative H-NMR spectrum test of mBCP-8 shows that the polyester block is polyethylene glycol dodecanedioate (PED) with a content of 18%; the polyether block is polytetramethylene glycol (PTMO) with a content of 78%; the polyamide block is nylon 1012 with a content of 4%, and the molecular weight of mBCP-8 is 12.1 kg / mol.

[0036] The preparation method of polyetheresteramide multi-block copolymer mBCP-9 is similar to that of mBCP-2, except that it is prepared by mixing musk T (16.5 g), polytetramethylene glycol (20.0 g, molecular weight 1000 g / mol), 1,10-decanediamine (3.5 g) and 8.0 μL tetrabutyl titanate. Quantitative nuclear magnetic hydrogen spectrum test of mBCP-9 shows that the polyester block is poly(ethylene glycol tridecanedioate) (PEB) with a content of 21%, the polyether block is polytetramethylene glycol (PTMO) with a content of 60%, and the polyamide block is nylon 1013 with a content of 19%.

[0037] The preparation method of polyetheresteramide multi-block copolymer mBCP-10 is similar to that of mBCP-1, except that it is prepared by mixing musk T (25.8 g), polytetramethylene glycol (3.0 g, molecular weight 1000 g / mol), 1,10-decanediamine (4.2 g) and 6.0 μL tetrabutyl titanate. Quantitative H-NMR spectrum test of mBCP-10 showed that the polyester block was poly(ethylene glycol tridecanedioate) (PEB) with a content of 61%, the polyether block was polytetramethylene glycol (PTMO) with a content of 11%, and the polyamide block was nylon 1013 with a content of 28%.

[0038] The preparation method of polyetheresteramide multi-block copolymer mBCP-11 is similar to that of mBCP-1, except that it is prepared by mixing musk T (16.5 g), polyethylene glycol (10.0 g, molecular weight 2000 g / mol), 1,10-decanediamine (3.5 g) and 6.0 μL tetrabutyl titanate. Quantitative nuclear magnetic hydrogen spectrum test of mBCP-11 shows that the polyester block is polyethylene tridecane dioate (PEB) with a content of 41%, the polyether block is polyethylene oxide (PEO) with a content of 32%, and the polyamide block is nylon 1013 with a content of 27%.

[0039] In the following examples of the present invention, the intrinsic viscosity of the product was measured using an Ubbelohde viscometer, using m-cresol as the solvent and the temperature was 25°C.

[0040] In the following embodiments of the present invention, the tensile properties of the epoxy resin cured product were tested using an Instron-3365 universal material testing machine (tensile rate: 10 mm / min, temperature: 20.0 °C, humidity: 70.0%).

[0041] In the following embodiments of the present invention, according to GB / T 2567-2021 standard, an FPP-01A impact testing machine is used to test the simply supported beam notched impact performance of the epoxy resin cured product.

[0042] In the following embodiments of the present invention, the transmittance of the epoxy resin cured product was tested using a Shimadzu UV-3150 UV-vis spectrophotometer (temperature: 25 °C, wavelength: 600 nm). Example 1

[0043] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is a polyetheresteramide multi-block copolymer mBCP-1.

[0044] 12.0 g BE-188EL epoxy resin was mixed with 0.60 g mBCP-1, heated to 70 °C, stirred for 30 min, mixed evenly, and cooled to room temperature; 2.64 g isophorone diamine was added and mixed evenly, and then cured at 40 °C for 1 h, 80 °C, 120 °C, and 160 °C for 2 h in sequence to obtain epoxy resin cured product EP-1, whose stress-strain curve is shown in the figure. Figure 1 shown.

[0045] The obtained epoxy resin cured product was tested for impact resistance and tensile properties, and the results are shown in Table 2. The light transmittance of the epoxy resin cured product EP-1 relative to the pure epoxy resin (Comparative Example EP) was measured to be 94%. Example 2

[0046] The present embodiment provides a method for preparing a cured epoxy resin, which is the same as the epoxy resin toughening modifier used in Example 1, except that: 12.0 g BE-188EL epoxy resin is mixed with 0.24 g mBCP-1, the temperature is raised to 70°C, stirred for 1 h, mixed evenly, and cooled to room temperature; 2.64 g isophorone diamine is added and mixed, and after mixing evenly, the mixture is cured at 40°C for 1 h, and then cured at 80°C, 120°C, and 160°C for 2 h in sequence to obtain a cured epoxy resin EP-2.

[0047] The impact resistance and tensile properties of the obtained epoxy resin cured product were tested, and the results are shown in Table 2. Example 3

[0048] This embodiment provides a method for preparing a cured epoxy resin, which is the same as the epoxy resin toughening modifier used in Example 1, except that: 12.0 g BE-188EL epoxy resin and 0.12 g mBCP-1 are mixed, heated to 70°C, stirred for 20 min, mixed evenly, and cooled to room temperature; 2.64 g isophorone diamine is added, mixed evenly, and cured at 40°C for 1 h, 80°C, 120°C, and 160°C for 2 h in sequence to obtain a cured epoxy resin EP-3, whose stress-strain curve is shown in FIG. Figure 2 shown.

[0049] The impact resistance and tensile properties of the obtained epoxy resin cured product were tested, and the results are shown in Table 2. Example 4

[0050] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is a polyetheresteramide multi-block copolymer mBCP-2.

[0051] 12.0 g BE-188EL epoxy resin was mixed with 0.60 g mBCP-2, heated to 130 °C, stirred for 1 h, mixed evenly, and cooled to room temperature; 2.64 g isophorone diamine was added and mixed evenly, and then cured at 40 °C for 1 h, and then cured at 80 °C, 120 °C, and 160 °C for 2 h in sequence to obtain epoxy resin cured product EP-4, whose stress-strain curve is shown in the figure. Figure 3 shown.

[0052] The obtained epoxy resin cured product was tested for impact resistance and tensile properties, and the results are shown in Table 2. The light transmittance of the epoxy resin cured product EP-4 relative to the pure epoxy resin (Comparative Example EP) was measured to be 83%. Example 5

[0053] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is polyetheresteramide multi-block copolymer mBCP-3.

[0054] The preparation process of epoxy resin cured material is similar to that of Example 4, except that the toughening agent mBCP-2 is replaced by the toughening agent mBCP-3 of the same mass to obtain epoxy resin cured material EP-5.

[0055] The obtained epoxy resin cured product was tested for impact resistance and tensile properties, and the results are shown in Table 2. The light transmittance of the epoxy resin cured product EP-5 relative to the pure epoxy resin (Comparative Example EP) was measured to be 88%. Example 6

[0056] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is a polyetheresteramide multi-block copolymer mBCP-4.

[0057] The preparation process of epoxy resin cured material is similar to that of Example 1, except that the toughening agent mBCP-4 is used in place of the toughening agent mBCP-1 with the same mass to obtain epoxy resin cured material EP-6.

[0058] The obtained epoxy resin cured product was tested for impact resistance and tensile properties, and the results are shown in Table 2. The light transmittance of the epoxy resin cured product EP-6 relative to the pure epoxy resin (Comparative Example EP) was measured to be 94%. Example 7

[0059] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is polyetheresteramide multi-block copolymer mBCP-5.

[0060] The preparation process of epoxy resin cured material is similar to that of Example 4, except that the toughening agent mBCP-5 is used in place of the toughening agent mBCP-2 with the same mass to obtain epoxy resin cured material EP-7.

[0061] The impact resistance and tensile properties of the obtained epoxy resin cured product were tested, and the results are shown in Table 2. Example 8

[0062] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is polyetheresteramide multi-block copolymer mBCP-6.

[0063] The preparation process of epoxy resin cured material is similar to that of Example 1, except that the toughening agent mBCP-6 is used in place of the toughening agent mBCP-1 with the same mass to obtain epoxy resin cured material EP-8.

[0064] The obtained epoxy resin cured product was tested for impact resistance and tensile properties, and the results are shown in Table 2. The light transmittance of the epoxy resin cured product EP-8 relative to the pure epoxy resin (Comparative Example EP) was measured to be 89%. Example 9

[0065] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is polyetheresteramide multi-block copolymer mBCP-7.

[0066] The preparation process of epoxy resin cured material is similar to that of Example 1, except that the toughening agent mBCP-7 of the same mass is used to replace the toughening agent mBCP-1 to obtain epoxy resin cured material EP-9.

[0067] The impact resistance and tensile properties of the obtained epoxy resin cured product were tested, and the results are shown in Table 2. Example 10

[0068] This embodiment provides a method for preparing a cured epoxy resin, and the specific steps are as follows: The epoxy resin toughening modifier of this embodiment is polyetheresteramide multi-block copolymer mBCP-8.

[0069] The preparation process of epoxy resin cured material is similar to that of Example 4, except that the toughening agent mBCP-8 is used in place of the toughening agent mBCP-2 with the same mass to obtain epoxy resin cured material EP-10.

[0070] The impact resistance and tensile properties of the obtained epoxy resin cured product were tested, and the results are shown in Table 2. Comparative Example 1

[0071] This comparative example provides a method for preparing a cured epoxy resin, and the specific steps are as follows: 12.0 g BE-188EL epoxy resin was mixed with 2.64 g isophorone diamine. After mixing evenly, the mixture was cured at 40 °C for 1 h, and then cured at 80 °C, 120 °C, and 160 °C for 2 h to obtain epoxy resin cured product EP. Its stress-strain curve is shown in the figure below. Figure 4 shown.

[0072] The obtained epoxy resin cured product was tested for impact resistance and tensile properties, and the results are shown in Table 2. Figure 5As shown, the light transmittance of the cured products of modified epoxy resins such as EP-1, EP-6 and EP-8 is close to that of the comparative example, indicating that the epoxy resin still maintains good light transmittance after adding toughening agent. Comparative Example 2

[0073] The polyetheresteramide multi-block copolymer provided in this comparative example is a polyetheresteramide multi-block copolymer mBCP-9. 12.0 g BE-188EL epoxy resin was mixed with 0.60 g mBCP-9, heated to 150 °C, and stirred for 2 h. mBCP-9 is incompatible with the epoxy resin matrix and cannot toughen and modify the epoxy resin. Comparative Example 3

[0074] The polyetheresteramide multi-block copolymer provided in this comparative example is polyetheresteramide multi-block copolymer mBCP-10.

[0075] 12.0 g BE-188EL epoxy resin was mixed with 0.60 g mBCP-10, heated to 150 °C, and stirred for 2 h. mBCP-10 is incompatible with the epoxy resin matrix and cannot toughen the epoxy resin. Comparative Example 4

[0076] The polyetheresteramide multi-block copolymer provided in this comparative example is the polyetheresteramide multi-block copolymer mBCP-11.

[0077] 12.0 g BE-188EL epoxy resin was mixed with 0.60 g mBCP-11, heated to 150 °C, and stirred for 2 h. mBCP-11 is incompatible with the epoxy resin matrix and cannot toughen the epoxy resin.

[0078] Table 2 Impact toughness and tensile strength of epoxy resin materials

[0079] Impact strength is used to characterize the toughness of epoxy resin cured products. As shown in Table 2, after adding the toughening agent of the present invention, as shown in Examples 1-10, the toughness and strength of epoxy resin cured products are significantly improved, the impact strength can be increased by more than 100%, and the strength can be increased by more than 40%. Figure 6 shown.

[0080] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A cured epoxy resin, characterized in that: The modified epoxy resin is obtained by curing; the modified epoxy resin comprises the following components: an epoxy resin matrix, an epoxy resin toughening modifier and a curing agent; The epoxy resin toughening modifier is a polyetheresteramide multi-block copolymer; the polyetheresteramide multi-block copolymer is composed of three blocks of aliphatic polyether, aliphatic polyester and aliphatic polyamide; The content of the aliphatic polyether is 60 wt %~90 wt %; the content of the aliphatic polyester is 10 wt %~30 wt %; the content of the aliphatic polyamide is 1 wt %~12 wt %, and the sum of the contents of each component is 100 wt %.

2. The epoxy resin cured product according to claim 1, characterized in that The epoxy resin matrix is ​​selected from bisphenol A epoxy resin with an epoxy value of 0.1 to 0.6; the bisphenol A epoxy resin is selected from one or more of E-12, E-44, E-51 and BE-188EL.

3. The epoxy resin cured product according to claim 1, characterized in that The curing agent is an amine curing agent; the amine curing agent is selected from one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and isophoronediamine.

4. The epoxy resin cured product according to claim 1, characterized in that: The chemical structural formula of the polyetheresteramide multi-block copolymer is as follows: ； Wherein, a is any integer from 2 to 6; b is any integer from 2 to 11; c is any integer from 2 to 4; d is any integer from 5 to 12; e is any integer from 4 to 68; f, g, and h are determined by the contents of the aliphatic polyester, the aliphatic polyether, and the aliphatic polyamide, respectively; and the number average molecular weight of the multi-block copolymer is 6000 g / mol to 50000 g / mol.

5. The epoxy resin cured product according to claim 1, characterized in that: The aliphatic polyether is polyethylene oxide and / or polytetrahydrofuran; the number average molecular weight of the aliphatic polyether is 200 g / mol to 3000 g / mol.

6. The epoxy resin cured product according to claim 1, characterized in that: The aliphatic polyester is a polyaliphatic diacid diol ester; the polyaliphatic diacid diol ester is selected from one or more of polyethylene adipate, polybutylene succinate, polyethylene tridecanoate and polyethylene dodecanoate.

7. The epoxy resin cured product according to claim 1, characterized in that: The aliphatic polyamide is selected from one or more of nylon 1013, nylon 613, nylon 1213, nylon 104 and nylon 1012.

8. The epoxy resin cured product according to claim 1, characterized in that: The mass ratio of the epoxy resin matrix to the epoxy resin toughening modifier is 200:1 to 10:1; And / or, the molar ratio of the amount of the curing agent to the epoxy value of the epoxy resin matrix is ​​2:1~1:

2.

9. The epoxy resin cured product according to claim 1, characterized in that: The light transmittance of the epoxy resin cured product is greater than 80% of that of pure epoxy resin.

10. A method for preparing a cured epoxy resin, characterized in that: The method comprises the following steps: mixing an epoxy resin matrix with an epoxy resin toughening modifier, heating to 60°C to 150°C, stirring for 20 min to 1 h, mixing uniformly, and cooling to room temperature; adding a curing agent, mixing uniformly, and heating and curing in a mold to obtain the epoxy resin cured product.

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