A method for the production of epoxy materials under cyclic dynamic force fields and the products thereof

Abstract

The application discloses a method for preparing an epoxy material under a cyclic dynamic force field and a product thereof; the epoxy material is obtained by performing mold curing on an epoxy premix under the action of the cyclic dynamic force field. The cyclic dynamic force field is introduced in mold forming, the cyclic dynamic force field is applied to a curing process of the epoxy resin, and effective regulation and control on structural performance of the epoxy resin is realized. In a gelation-to-curing process of the epoxy premix, under the action of the cyclic dynamic force field, the crosslinking network of the epoxy molecular chain is orderly rearranged and disentangled, the epoxy profile with an orderly crosslinking network is prepared, and the mechanical performance of the sample is improved. Meanwhile, under the cyclic dynamic force field, the curing time of the epoxy profile is effectively shortened. The application is favorable for reducing production cost, improving production efficiency and product quality, and is an effective way for efficient production.

Description

Technical Field

[0001] This invention relates to the field of epoxy material molding technology, and in particular to a method for preparing epoxy materials and their products under a cyclic dynamic force field. Background Technology

[0002] Epoxy resin is a general term for a class of thermosetting materials containing epoxy groups. As a chemically reactive material, the different chemical structures of linear epoxy molecules and curing agents endow cured epoxy resins with a wide variety of applications. They are widely used in the energy, transportation, and aerospace sectors in the form of structural components. With the development of science and technology and the expansion into advanced fields, traditional polymer materials are increasingly unable to meet the application requirements of these new fields.

[0003] Therefore, the preparation of high-performance epoxy resins and their composites using advanced manufacturing technologies has become an inevitable trend to adapt to development. Shortening curing time is a crucial step in the processing of thermosetting materials and is key to cost savings and efficiency improvements. Currently, most methods for preparing high-performance epoxy resins and their composites involve improvements to the chemical formulation. While changing the chemical formulation can effectively improve the performance of epoxy resins and their composites, it suffers from high costs and limited applicability. The patent "A High-Performance Thermosetting Resin Curing Agent / Diluent and Its Preparation Method" synthesizes a curing agent / diluent with low viscosity and high reactivity through reaction synthesis, thereby reducing the resin curing temperature and shortening the curing time, meeting the requirements of dry prepreg and resin transfer molding (RTM) processes. Compression molding is another commonly used method for processing epoxy resin profiles. Compared to RTM, compression molding does not have a gating system. Compression molding involves a venting process, eliminating the need for venting channels. Therefore, compression molding is simpler and has lower mold costs. During compression molding, the internal pressure is uniform, resulting in products with low internal stress, making it suitable for mass production of large, flat products. However, epoxy products prepared by existing compression molding processes have problems such as long curing time and poor mechanical properties. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method and product for preparing epoxy materials under a cyclic dynamic force field, which makes the operation simple, effectively shortens the curing time, and improves the mechanical properties of the profile, thus expanding the application range of the profile.

[0005] This invention differs from traditional constant-pressure molding processes by applying a cyclic dynamic force field to the curing process of epoxy resin, thereby achieving effective control over the curing process and structural properties of the epoxy resin. In this process, the curing time is effectively shortened, and the mechanical properties of epoxy and its composites are improved.

[0006] The technical solution of this invention is as follows:

[0007] A method for preparing epoxy materials under a cyclic dynamic force field includes the following steps:

[0008] Epoxy materials are obtained by molding and curing epoxy premixes under the action of a cyclic dynamic force field.

[0009] Preferably, the epoxy premix is ​​subjected to continuously changing pressure under the action of a cyclic dynamic force field, with a single period T... cycle It includes the pressure rise zone, the highest constant pressure zone, the pressure drop zone, and the lowest constant pressure zone.

[0010] More preferably, in the pressure rise zone, the pressure applied to the epoxy premix increases to the maximum pressure P during time period T1. max In the highest pressure constant pressure zone, the pressure applied to the epoxy premix remains constant P for time period T2. max In the pressure drop zone, the pressure applied to the epoxy premix during time period T3, from the maximum pressure P... max Decrease to P min In the lowest pressure constant pressure zone, the pressure applied to the epoxy premix is ​​maintained at a constant pressure P for time period T4. min ;

[0011] More preferably, the pressure P max Satisfying 5MPa≤P max ≤30MPa, P min Satisfying 0MPa≤P min <P max The time intervals T1 satisfy 0s < T1 ≤ 2s, T2 satisfy 0s ≤ T2 < 4s, T3 satisfy 0s < T3 ≤ 2s, and T4 satisfy 0s ≤ T3 < 4s.

[0012] More preferably, the time T of the single period cycle Satisfying 0s < T cycle <4s; the number of cycles of the cyclic dynamic force field is 1 to 1000 (1, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 times, etc.).

[0013] Preferably, the epoxy premix is ​​molded and cured under a cyclic dynamic force field, and then molded and cured a second time under constant pressure; the constant pressure is the maximum pressure of the cyclic dynamic force field.

[0014] More preferably, the time for the second molding and curing under constant pressure is less than the total duration of the cyclic dynamic force field action; the temperature for the second molding and curing under constant pressure is 180-220℃.

[0015] Preferably, the epoxy premix comprises a pure epoxy system and an epoxy / filler system; the pure epoxy system comprises epoxy linear molecules and a curing agent; the epoxy / filler system comprises epoxy linear molecules, a curing agent, and a filler, wherein the filler comprises glass fiber, carbon fiber, silica, and montmorillonite.

[0016] More preferably, the mass ratio of the epoxy linear molecule to the curing agent is 75-100:25; and the mass ratio of the epoxy linear molecule to the filler is 50-100:50.

[0017] Preferably, the molding and curing temperature is 80-120℃;

[0018] Preferably, the epoxy material after molding and curing is demolded after cooling, and the cooling method is liquid cooling or natural cooling.

[0019] The epoxy material prepared by the above method.

[0020] The present invention has the following advantages:

[0021] This invention applies a cyclic dynamic force field to an epoxy premix, causing the cross-linked network of epoxy molecular chains to rearrange and untangle in an orderly manner, thereby preparing epoxy profiles with an ordered cross-linked network. This is beneficial for shortening curing time and improving the mechanical properties of epoxy products. Attached Figure Description

[0022] Figure 1 The pressure of the cyclic dynamic force field of this invention Time-relationship curve.

[0023] Figure 2 The pressure within a single cycle under cyclic dynamic force fields with different parameters in Examples 1-3 of this invention. Time-relationship curve.

[0024] Figure 3 The compressive stress of epoxy resin sheets prepared under different cyclic dynamic force fields in Examples 1-3 of this invention and the epoxy resin sheets prepared in the control group are shown. Strain curves, where control group 1 and control group 2 are control samples.

[0025] Figure 4 The tensile stress of epoxy resin sheets prepared under different cyclic dynamic force fields in Examples 1-3 of this invention and the epoxy resin sheets prepared in the control group are shown. Strain curves, where control group 2 is the control sample.

[0026] Figure 5 The pressure within a single cycle under the cyclic dynamic force field in embodiments 4 and 5 of the present invention. Time-relationship curve.

[0027] Figure 6 The tensile stress of the epoxy composite materials prepared under cyclic dynamic force fields in Examples 4 and 5 of this invention. Strain curve. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The present invention provides a method for preparing epoxy materials under a cyclic dynamic force field. During the gelation and curing process of the epoxy premix, the polymer molecular chain crosslinking network of the premix undergoes orderly rearrangement and unentanglement under the action of a cyclic dynamic force field, thereby preparing an epoxy profile with an ordered crosslinking network.

[0030] The epoxy premix is ​​molded under a cyclic dynamic force field and subjected to continuous periodic pressure changes. A single cycle includes a pressure rise zone, a maximum constant pressure zone, a pressure fall zone, and a minimum constant pressure zone.

[0031] In the pressure rise zone, the pressure applied to the material increases to the maximum pressure P within time period T1. max In the highest pressure constant pressure zone, the pressure applied to the material remains constant P for time period T2. max In the pressure drop zone, the pressure applied to the material during time period T3 decreases from the maximum pressure P. max Decrease to P min In the lowest pressure constant pressure zone, the pressure applied to the material remains constant P for time period T4. min To ensure complete curing of the epoxy resin, after each continuous cycle, the premix is ​​subjected to a constant pressure P. max Press the lower mold for A minutes.

[0032] The epoxy premix includes a pure epoxy system and an epoxy / filler system; the pure epoxy system includes linear epoxy molecules and a curing agent; the epoxy / filler system includes both the components of the pure epoxy system and other fillers, wherein the fillers include, but are not limited to, glass fiber, carbon fiber, silica, montmorillonite, etc.

[0033] The pressure P max 5MPa≤P max ≤30MPa, the pressure P min Satisfying 0≤P min <P maxThe time interval T1 satisfies 0s < T1 ≤ 2s, the time interval T2 satisfies 0s ≤ T2 < 4s, the time interval T3 satisfies 0s < T3 ≤ 2s, and the time interval T4 satisfies 0s ≤ T3 < 4s. cycle For 0s < T cycle <4s.

[0034] The number of cycles in the continuous cycle is 1 to 1000; the constant pressure A minutes is less than the total duration of the cycle.

[0035] After the epoxy profile completes the molding process, it is demolded after cooling, either by liquid cooling or natural cooling.

[0036] Example 1

[0037] This embodiment describes a method for preparing epoxy materials under a cyclic dynamic force field. Epoxy resin (E51) and curing agent (T31) are mixed at a mass ratio of 75:25 using a Banbury mixer at room temperature and 60 rpm for 4 minutes. The blend is then collected. The blend is then processed in a molding machine, such as... Figure 1 As shown, by adjusting the motion law of the molding die, it can produce the following... Figure 2 The cyclic dynamic force field was determined (T1=1.095s, T2=0s, T3=1.095s, T4=0s). 200 molding cycles were performed at 90℃ and a maximum pressure of 20MPa, followed by molding at 220℃ and a constant pressure of 20MPa for 5 minutes to obtain epoxy resin sheet CPP1.

[0038] Example 2

[0039] This embodiment describes a method for preparing epoxy materials under a cyclic dynamic force field. Epoxy resin (E51) and curing agent (T31) are mixed at a mass ratio of 75:25 using a Banbury mixer at room temperature and 60 rpm for 4 minutes. The blend is then collected. The blend is then processed in a molding machine, such as... Figure 1 As shown, by adjusting the motion law of the molding die, it can produce the following... Figure 2 The cyclic dynamic force field was determined (T1=1.335s, T2=0s, T3=1.335s, T4=0s). 200 molding cycles were performed at 90℃ and a maximum pressure of 20MPa, followed by molding at 220℃ and a constant pressure of 20MPa for 5 minutes to obtain epoxy resin sheet CPP2.

[0040] Example 3

[0041] This embodiment describes a method for preparing epoxy materials under a cyclic dynamic force field. Epoxy resin (E51) and curing agent (T31) are mixed at a mass ratio of 75:25 using a Banbury mixer at room temperature and 60 rpm for 4 minutes. The blend is then collected. The blend is then processed in a molding machine, such as... Figure 1 As shown, by adjusting the motion law of the molding die, it can produce the following... Figure 2 The cyclic dynamic force field (T1=1.62s, T2=0s, T3=1.62s, T4=0s) was used to process epoxy resin sheets CPP3 by performing 200 molding cycles at 90℃ and a maximum pressure of 20MPa, followed by molding at 220℃ and a constant pressure of 20MPa for 5 minutes.

[0042] control group

[0043] Epoxy resin (E51) and curing agent (T31) were mixed at a mass ratio of 75:25 using an internal mixer at 60 rpm for 4 minutes at room temperature. The blend was then collected. The blend was then placed in a molding machine for processing.

[0044] The processing conditions for the control group were as follows: molding at 90℃ and 20MPa constant pressure for 10 min, followed by molding at 220℃ and 20MPa constant pressure for 5 min to obtain control group sample 1; molding at 90℃ and 20MPa constant pressure for 20 min, followed by molding at 220℃ and 20MPa constant pressure for 5 min to obtain control group sample 2.

[0045] Figure 3 The figures show the compressive stress-strain curves of epoxy resin sheets prepared under different cyclic dynamic force fields in Examples 1-3 and the epoxy resin sheets prepared in the control group. Compared with the control group sample 1 prepared by constant molding, the yield strength and modulus of the experimental group CPP1, CPP2, and CPP3 are all improved, while the modulus is close to that of the control group sample 2. The modulus increases from 111 MPa in the control group sample 1 to 118 MPa, 144 MPa, and 142 MPa, respectively, showing a significant self-reinforcing effect. At the same time, the processing time of CPP1 and CPP2 is shorter than that of the control group sample 1, indicating that this processing method is effective in shortening the curing time.

[0046] Figure 4The tensile stress-strain curves of epoxy resin sheets prepared under different cyclic dynamic force fields in Examples 1-3 and the epoxy resin sheets prepared in the control group are shown (the performance of control group sample 1 was too poor to prepare tensile specimens for testing). Compared with control group sample 2 prepared by constant molding, the tensile strength and modulus of experimental group CPP1, CPP2, and CPP3 are close to the performance of control group sample 2. The processing time of experimental group samples is shorter than that of control group sample 2, indicating that this processing method has an effective effect in shortening the curing time.

[0047] Example 4

[0048] This embodiment describes a method for preparing epoxy materials under a cyclic dynamic force field. Epoxy resin (E51) and glass fiber (3mm in length) are mixed at a mass ratio of 60:40 using an internal mixer at room temperature and 60 rpm for 3 minutes. Then, epoxy resin and curing agent (T31) are mixed at a mass ratio of 75:25 using an internal mixer at room temperature and 60 rpm for 4 minutes. The blend is collected. The blend is then placed in a molding press for processing. By controlling the movement of the moving mold platen in the molding press, a process is achieved... Figure 5 The cyclic dynamic force field was determined (T1=1.335s, T2=0s, T3=1.335s, T4=0s). 200 molding cycles were performed at 90℃ and a maximum pressure of 20MPa, followed by molding at 220℃ and a constant pressure of 20MPa for 5 minutes to obtain epoxy resin sheet FG40.

[0049] Example 5

[0050] This embodiment describes a method for preparing epoxy materials under a cyclic dynamic force field. Epoxy resin (E51) and glass fiber (3mm in length) are mixed at a mass ratio of 80:20 using an internal mixer at room temperature and 60 rpm for 3 minutes. Then, epoxy resin and curing agent (T31) are mixed at a mass ratio of 75:25. The curing agent is added and the mixture is further mixed using an internal mixer at room temperature and 60 rpm for 4 minutes. The blend is collected. The blend is then placed in a molding press for processing. By controlling the movement of the moving mold platen, a process is achieved... Figure 5 The cyclic dynamic force field was determined (T1=1.335s, T2=0s, T3=1.335s, T4=0s). 200 molding cycles were performed at 90℃ and a maximum pressure of 20MPa, followed by molding at 220℃ and a constant pressure of 20MPa for 5 minutes to obtain epoxy resin sheet FG20.

[0051] Figure 6The stress-strain curves of the epoxy resin sheets prepared under cyclic dynamic force fields in Examples 4 and 5 are shown. Under the same dynamic cyclic force field, the tensile strength of FG40 increases with the increase of glass fiber content compared to FG20, proving that the epoxy composite material prepared under cyclic dynamic force field conforms to the mechanical laws and that cyclic dynamic force field is suitable for the preparation of epoxy composite materials.

[0052] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing epoxy materials under a cyclic dynamic force field, characterized in that, Includes the following steps: Epoxy materials are obtained by molding and curing epoxy premixes under cyclic dynamic force fields. The epoxy premix undergoes molding and curing under the action of a cyclic dynamic force field, which is the gel-to-curing stage. The epoxy premix is ​​subjected to continuously changing pressure under the action of the cyclic dynamic force field, and a single cycle Tcycle includes a pressure rise zone, a maximum pressure constant zone, a pressure fall zone, and a minimum pressure constant zone. In the pressure rise zone, the pressure applied to the epoxy premix increases to the maximum pressure Pmax in time period T1. In the highest constant pressure zone, the pressure applied to the epoxy premix remains constant at Pmax during time period T2; in the pressure decrease zone, the pressure applied to the epoxy premix decreases from the maximum pressure Pmax to Pmin during time period T3; in the lowest constant pressure zone, the pressure applied to the epoxy premix remains constant at Pmin during time period T4; the pressure Pmax satisfies 5MPa≤Pmax≤30MPa, Pmin satisfies 0MPa≤Pmin<Pmax, the time periods T1 satisfy 0s<T1≤2s, T2 satisfies 0s≤T2<4s, T3 satisfies 0s<T3≤2s, and T4 satisfies 0s≤T4<4s, the single period T... cycle Satisfy: 0s < T cycle <4s; the number of cycles of the cyclic dynamic force field is 200; the molding curing temperature is 80-120℃; the epoxy premix is ​​molded and cured under the cyclic dynamic force field and then molded and cured a second time under constant pressure; the constant pressure is the maximum pressure of the cyclic dynamic force field; the time for the second molding and curing under constant pressure is 5min, and the temperature is 220℃.

2. The method according to claim 1, characterized in that, The epoxy premix includes a pure epoxy system and an epoxy / filler system; the pure epoxy system includes linear epoxy molecules and a curing agent; the epoxy / filler system includes linear epoxy molecules, a curing agent, and a filler.

3. The method according to claim 2, characterized in that, The filler includes glass fiber, carbon fiber, silica, and montmorillonite; the mass ratio of the epoxy linear molecules to the curing agent is 75-100:25; the mass ratio of the epoxy linear molecules to the filler is 50-100:

50.

4. The method according to claim 1, characterized in that, The epoxy material, after being molded and cured, is demolded after cooling, either by liquid cooling or natural cooling.

5. The epoxy material prepared by the method according to any one of claims 1-4.

Images