Epoxy resin composition for winding fiber prepreg tape and preparation method thereof

Abstract

The invention discloses an epoxy resin composition for winding a fiber prepreg tape and a preparation method of the epoxy resin composition, and relates to the technical field of composites.The epoxy resin composition is prepared from 50-100 parts of liquid epoxy resin, 10-40 parts of solid epoxy resin, 3-10 parts of curing agent, 3-10 parts of accelerant and 0.1-2 parts of auxiliaries. Stirring at 100 DEG C until the mixture is molten, and cooling to 65 DEG C to obtain a component A; the curing agent, the accelerant, the liquid epoxy resin and the auxiliaries are additionally stirred and subjected to three-axis grinding to serve as a component B; and adding the component B into the component A, stirring for 30 minutes, and then sub-packaging and freezing to overnight. According to the epoxy resin composition for winding the fiber prepreg tape and the preparation method of the epoxy resin composition, the epoxy resin composition has proper operability and can be well matched with a dry winding process, and key processing variables such as the fiber direction and the resin content are conveniently and accurately controlled in the dry winding process, so that the quality of a finished product is more uniform and consistent.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, in particular to an epoxy resin composition for fiber prepreg tape winding and a preparation method thereof. Background Art

[0002] Fiber-reinforced composite materials have been widely used in many fields such as aerospace, automobile manufacturing, energy development, sports equipment, etc. due to their high strength, high modulus, low density and excellent corrosion resistance. In the molding process of these composite materials, the winding process is an important manufacturing method, which can make the fiber direction parallel to the circumference of the pipe or bottle, reduce the fiber breakpoint, and thus make the fiber tension most effectively exerted. Epoxy resin has become a commonly used matrix resin in the fiber prepreg winding process due to its excellent bonding properties, good mechanical properties, chemical stability and good compatibility with fibers. However, with the continuous expansion of the application field of composite materials and the increasing requirements for material performance, traditional liquid epoxy resin compositions have gradually exposed some problems in the epoxy resin fiber winding process.

[0003] The existing epoxy resin winding technology requires simultaneous impregnation of resin during winding, so the resin must be designed to be liquid. During the production process, liquid resin is prone to flow and drip, and the amount of resin attached to the fiber is difficult to control, resulting in uneven thickness of the wound part, affecting the stability of physical properties. Liquid resin is also prone to causing the fiber to slide and deviate during winding, making it impossible for the fiber to be laid in the designed direction, reducing the mechanical performance of the finished product. Moreover, liquid resin needs to be exposed to the atmosphere for a long time during winding, and is prone to absorbing moisture and deteriorating, seriously affecting the physical properties of the wound part. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides an epoxy resin composition for fiber prepreg winding and a preparation method thereof, which solves the problem of uneven thickness of the winding parts and serious impact on the stability of physical properties proposed in the above background technology.

[0005] To achieve the above object, the present invention is implemented by the following technical scheme: an epoxy resin composition for fiber prepreg winding, the proportion of which is as follows: 50-100 parts of liquid epoxy resin, 10-40 parts of solid epoxy resin, 3-10 parts of curing agent, 3-10 parts of accelerator, and 0.1-2 parts of auxiliary agent; The preparation method is as follows: pouring liquid epoxy resin and solid epoxy resin into a stirring tank, stirring at 100°C until melted, and then cooling to 65°C to form component A; The curing agent, accelerator, liquid epoxy resin and additives are separately stirred and three-axis ground as component B; Add component B to component A, stir for 30 minutes and then divide into portions and freeze overnight.

[0006] Furthermore, the liquid epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, reactive epoxy diluent, pre-reactant of polyurethane and epoxy resin, pre-reactant of dibasic acid and epoxy resin, pre-reactant of CTBN and epoxy resin, and grinding liquid of methyl methacrylate-butadiene-styrene and epoxy resin.

[0007] Furthermore, the solid epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, cresol novolac epoxy resin, bisphenol A formaldehyde epoxy resin, phenoxy resin, and oxazolidone epoxy resin.

[0008] Furthermore, the solid epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, cresol novolac epoxy resin, bisphenol A formaldehyde epoxy resin, phenoxy resin, and oxazolidone epoxy resin.

[0009] Furthermore, the curing agent is one of dicyandiamide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, amine adduct, hydrazide, and microcapsule curing agent.

[0010] Furthermore, the accelerator is one of tertiary amine, quaternary ammonium salt, imidazole, boron trifluoride amine, antimony pentafluoride amine, organic urea, and amine adduct.

[0011] Furthermore, the auxiliary agent is one or more of a diluent, a stabilizer, a coupling agent, a defoaming agent, and a wetting and leveling agent.

[0012] Furthermore, the fiber prepreg tape winding molding process is as follows: the resin is applied to the release paper to form a film, and the film is pressed and impregnated with the fiber to form a fiber prepreg tape. Then the fiber prepreg tape is wound on the inner liner or the central axis, and the prepreg tape is attached to the workpiece by heat melting or pressure.

[0013] Further, component B is added to component A at a stirring condition of 60-90° C. and 30-1000 r / min, and mixed evenly to obtain an epoxy resin composition.

[0014] The present invention provides an epoxy resin composition for fiber prepreg tape winding and a preparation method thereof, which have the following beneficial effects: suitable operability, good coordination with a dry winding process, and during the dry winding process, it is convenient to accurately control key processing variables such as fiber direction and resin content, so that the quality of the finished product is more uniform, and it is allowed to add high-viscosity components such as toughening agents and fillers, which greatly improves the freedom of the formulation, and selects latent curing agents such as dicyandiamide, organic urea and imidazole. These curing agents are relatively insensitive to environmental humidity. In actual production and use environments, humidity changes are not likely to significantly interfere with the curing process, thereby ensuring the stability of the quality of the finished product, and through the reasonable combination of epoxy resins with different molecular weights, the viscosity and fluidity of the system are effectively improved, the curing temperature and curing time are reduced, and the impact resistance and dimensional stability of the product are enhanced. DETAILED DESCRIPTION

[0015] The following examples are used to illustrate the present invention, but they are not intended to limit the scope of the present invention. Example 1

[0016] The present embodiment discloses an epoxy resin composition for fiber prepreg winding, comprising 50 parts of liquid epoxy resin, 10 parts of solid epoxy resin, 3 parts of curing agent, 3 parts of accelerator, and 0.1 parts of auxiliary agent. The liquid epoxy resin and the solid epoxy resin are poured into a stirring tank, stirred at 100° C. until melted, and then cooled to 65° C. to obtain component A; the curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and ground with three axes to obtain component B; and component B is added to component A and stirred for 30 minutes to obtain the product. Example 2

[0017] The present embodiment discloses an epoxy resin composition for fiber prepreg winding, comprising 70 parts of liquid epoxy resin, 20 parts of solid epoxy resin, 5 parts of curing agent, 5 parts of accelerator, and 0.5 parts of auxiliary agent. The liquid epoxy resin and the solid epoxy resin are poured into a stirring tank, stirred at 100° C. until melted, and then cooled to 65° C. to obtain component A; the curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and ground with three axes to obtain component B; and component B is added to component A and stirred for 30 minutes to obtain the product. Example 3

[0018] The present embodiment discloses an epoxy resin composition for fiber prepreg winding, comprising 90 parts of liquid epoxy resin, 30 parts of solid epoxy resin, 7 parts of curing agent, 7 parts of accelerator, and 1 part of auxiliary agent. The liquid epoxy resin and the solid epoxy resin are poured into a stirring tank, stirred at 100° C. until melted, and then cooled to 65° C. to obtain component A; the curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and ground with three axes to obtain component B; and component B is added to component A and stirred for 30 minutes to obtain the product. Example 4

[0019] The present embodiment discloses an epoxy resin composition for fiber prepreg winding, comprising 100 parts of liquid epoxy resin, 40 parts of solid epoxy resin, 10 parts of curing agent, 10 parts of accelerator, and 2 parts of auxiliary agent. The liquid epoxy resin and the solid epoxy resin are poured into a stirring tank, stirred at 100° C. until melted, and then cooled to 65° C. to obtain component A; the curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and ground with three axes to obtain component B; and component B is added to component A and stirred for 30 minutes to obtain the product.

[0020] The above embodiments are all prepared by the same method, that is, liquid epoxy resin and solid epoxy resin are poured into a stirring tank, stirred at 100°C until melted, and then cooled to 65°C to form component A; curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and triaxially ground to form component B; component B is then added to component A, stirred for 30 minutes, and then packaged and frozen overnight.

[0021] Table 1 Performance test data of Examples 1-4

[0022] As can be seen from Table 1, the epoxy resin composition for fiber prepreg winding prepared by the present invention has good process performance, fast curing speed, and excellent mechanical properties after curing. With the gradual increase in the content of liquid epoxy resin, solid epoxy resin, curing agent, accelerator and auxiliary agent (from Example 1 to Example 4), the tensile strength shows an upward trend, reaching 75MPa in Example 4, which is significantly improved compared with 55MPa in Example 1. This is because the components work together to form a denser and tougher cross-linked network structure after curing, so that it can better withstand tensile external forces. Similarly, the bending strength also increases with the change in the proportion of each component. The bending strength of Example 4 is 120MPa, which is significantly improved compared with 80MPa in Example 1. The higher content of epoxy resin and other additives helps to enhance the resistance of the material under bending load, so that the composite material is not easy to break when subjected to bending stress. The elongation at break gradually increases from Example 1 to Example 4, from 3.5% to 4. The results show that the flexibility of the material is improved with the adjustment of the formula. The reasonable combination of ingredients enables the epoxy resin composition to maintain a certain strength after curing and to deform to a certain extent without breaking when subjected to stress. This is very important for some fiber prepreg tape winding products that need to withstand dynamic loads or are used in complex stress environments. The glass transition temperature increases with the increase of each component, from 120°C in Example 1 to 150°C in Example 4. The higher glass transition temperature means that the material can still maintain good mechanical properties and dimensional stability in a high temperature environment, which broadens its application temperature range and is suitable for some fields with high requirements for heat resistance, such as aerospace, automobile engine peripheral parts, etc. The viscosity gradually increases from Example 1 to Example 4, from 2500mPa·s Increased to 4500mPa·s. This is because the change in the content of each component affects the rheological properties of the system. Within a certain range, appropriately increasing the viscosity is helpful to better control the flow and impregnation effect of the resin during the fiber prepreg winding process, ensure sufficient infiltration between the fiber and the resin, and improve the quality of the composite material. However, too high viscosity may bring certain difficulties to the winding process, which needs to be optimized and adjusted according to the specific production process and equipment. The curing time is shortened as the component ratio changes, from 180min in Example 1 to 120min in Example 4. This is because the increase in the content of the curing agent and the accelerator accelerates the curing reaction speed of the epoxy resin. A shorter curing time is conducive to improving production efficiency. However, in practical applications, it is necessary to comprehensively consider the matching of the curing speed and the process operation time to ensure that the winding and curing process are completed within a suitable time, while ensuring the curing quality. By comparing and analyzing the performance test data of Examples 1-4, it can be seen that the change in the proportion of each component has a significant effect on the performance of the epoxy resin composition for fiber prepreg winding.

[0023] Comparative Example 1 The comparative example discloses an epoxy resin composition for fiber prepreg winding, comprising 50 parts of liquid epoxy resin, 3 parts of curing agent, 3 parts of accelerator, and 0.1 parts of auxiliary agent. The liquid epoxy resin and solid epoxy resin are poured into a stirring tank, stirred at 100° C. until melted, and then cooled to 65° C. to obtain component A; the curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and ground with three axes to obtain component B; and component B is added to component A and stirred for 30 minutes to obtain the product.

[0024] Comparative Example 2 The comparative example discloses an epoxy resin composition for fiber prepreg winding, comprising 40 parts of solid epoxy resin, 10 parts of curing agent, 10 parts of accelerator, and 2 parts of auxiliary agent. Liquid epoxy resin and solid epoxy resin are poured into a stirring tank, stirred at 100° C. until melted, and then cooled to 65° C. to obtain component A; curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and ground by three axes to obtain component B; and component B is added to component A and stirred for 30 minutes to obtain the product.

[0025] The above two comparative examples all adopt the same preparation method, that is, pour the liquid epoxy resin into a stirring tank, stir it at 100°C until it melts, and then cool it to 65°C, as component A; the curing agent, accelerator, liquid epoxy resin and auxiliary agent are separately stirred and ground with a three-axis grinder, as component B; then component B is added to component A, stirred for 30 minutes, and then packaged and frozen overnight.

[0026] Table 2 Performance test data of comparative examples 1-2 Comparative Example Tensile strength (MPa) Bending strength (MPa) Elongation at break (%) Glass transition temperature (℃) Viscosity (mPa·s) Curing time (min) 1 40 60 2.5 100 2000 200 2 50 70 3.0 110 3000 150 Comparative Example 1 The tensile strength and flexural strength are relatively low: it contains only 50 parts of liquid epoxy resin and lacks effective supplementation of solid epoxy resin, resulting in an imperfect cross-linked network structure formed after curing, which is prone to weak links when subjected to tensile and bending loads. Therefore, the tensile strength is 40MPa and the flexural strength is 60MPa.

[0027] The elongation at break is low: Since the overall composition of the resin in the system is not balanced enough, the ability to deform when subjected to force is limited, the elongation at break is only 2.5%, and the material is relatively brittle.

[0028] The glass transition temperature is low: 100°C, which means that the performance of the composition may change significantly at a relatively low temperature, and the heat resistance is poor, so it is not suitable for application in high temperature environment.

[0029] Viscosity and curing time: The viscosity is 2000mPa·s, which is relatively low. During the winding process, there may be a lot of resin flow. The curing time is long, reaching 200 minutes, which will reduce production efficiency.

[0030] Comparative Example 2 The performance is better than that of Example 1 but worse than that of Example 4: it contains more solid epoxy resin and other ingredients, so that the tensile strength is increased to 50MPa, the flexural strength is increased to 70MPa, the elongation at break is 3.0%, and the glass transition temperature is 110°C, which is a certain improvement compared with Comparative Example 1. This is because the solid The addition of epoxy resin enhances the structural integrity and stability of the system to a certain extent.

[0031] Viscosity and curing time characteristics: The viscosity reaches 3000mPa·s, and the fluidity control of the resin during winding is relatively good, but it is still not as good as the effect of the comprehensive formula in Example 4; the curing time is 150 minutes, which is shorter than that of Comparative Example 1, but still longer than 120 minutes in Example 4. This shows that the formula of this comparative example still has room for optimization in terms of curing reaction speed and resin rheological properties.

[0032] By comparing with Example 4 and the two comparative examples, it can be more clearly seen that the importance of a reasonable combination of the components for the performance of the epoxy resin composition for fiber prepreg tape winding.

[0033] As can be seen from Table 2, the epoxy resin compositions for fiber prepreg winding prepared in Comparative Examples 1 and 2 have poor process performance, slow curing, and relatively poor mechanical properties after curing.

[0034] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. An epoxy resin composition for fiber prepreg winding, characterized in that: The proportions are as follows: 50-100 parts of liquid epoxy resin, 10-40 parts of solid epoxy resin, 3-10 parts of curing agent, 3-10 parts of accelerator, and 0.1-2 parts of auxiliary agent; The preparation method is as follows: pouring liquid epoxy resin and solid epoxy resin into a stirring tank, stirring at 100°C until melted, and then cooling to 65°C to form component A; The curing agent, accelerator, liquid epoxy resin and additives are separately stirred and three-axis ground as component B; Add component B to component A, stir for 30 minutes and then divide into portions and freeze overnight.

2. The epoxy resin composition for fiber prepreg winding according to claim 1, characterized in that: The liquid epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, reactive epoxy diluent, pre-reactant of polyurethane and epoxy resin, pre-reactant of dibasic acid and epoxy resin, pre-reactant of CTBN and epoxy resin, and grinding liquid of methyl methacrylate-butadiene-styrene and epoxy resin.

3. The epoxy resin composition for fiber prepreg winding according to claim 2, characterized in that: The solid epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, cresol novolac epoxy resin, bisphenol A formaldehyde epoxy resin, phenoxy resin, and oxazolidinone epoxy resin.

4. The epoxy resin composition for fiber prepreg winding according to claim 3, characterized in that: The solid epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, cresol novolac epoxy resin, bisphenol A formaldehyde epoxy resin, phenoxy resin, and oxazolidinone epoxy resin.

5. The epoxy resin composition for fiber prepreg winding according to claim 4, characterized in that: The curing agent is one of dicyandiamide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, amine adduct, hydrazide, and microcapsule curing agent.

6. The epoxy resin composition for fiber prepreg winding according to claim 5, characterized in that: The accelerator is one of tertiary amine, quaternary ammonium salt, imidazole, boron trifluoride amine, antimony pentafluoride amine, organic urea and amine adduct.

7. The epoxy resin composition for fiber prepreg winding according to claim 6, characterized in that: The additive is one or more of a diluent, a stabilizer, a coupling agent, a defoaming agent, and a wetting and leveling agent.

8. The epoxy resin composition for fiber prepreg winding according to claim 7, characterized in that: The fiber prepreg tape winding molding process is as follows: the resin is applied to the release paper to form a film, the film is pressed and impregnated with the fiber to make the fiber prepreg tape, and then the fiber prepreg tape is wound on the inner liner or the central axis, and the prepreg tape is adhered to the workpiece by heat melting or pressure.

9. A method for preparing an epoxy resin composition for fiber prepreg winding according to any one of claims 1 to 8, characterized in that: Add component B into component A at 60-90° C. and 30-1000 r / min, and mix well to obtain an epoxy resin composition.

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