Resin composition with high and low temperature fracture toughness and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to a resin composition with high and low temperature fracture toughness and application thereof.The resin composition is prepared from, by weight, 30-50 parts of bisphenol A epoxy resin, 5-15 parts of carboxyl-terminated liquid nitrile rubber, 10-25 parts of aromatic compounds and 5-20 parts of filler. The resin composition with high and low temperature fracture toughness is applied to the field of sports equipment manufacturing, including bicycle frames, snowboards, badminton rackets and tennis rackets. The resin composition provided by the invention has excellent fracture toughness in both high and low temperature environments, is suitable for the field of sports equipment, and can meet the performance requirements of the sports equipment in different use scenes.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a resin composition having high and low temperature fracture toughness and an application thereof. Background Art

[0002] Resin materials are widely used in many fields due to their excellent comprehensive properties. However, traditional resin materials often show poor fracture toughness in high and low temperature environments. In low temperature environments, resin materials become brittle and hard, and are prone to brittle fracture; in high temperature environments, the mechanical properties of the resin decrease, resulting in a decrease in its load-bearing capacity, and it is also prone to fracture damage.

[0003] Among them, due to its good adhesion and mechanical properties, it is widely used in the field of sports equipment manufacturing. However, traditional epoxy resins have obvious defects and are difficult to meet the use requirements of sports equipment in complex environments. For example, when riding a bicycle outdoors in high temperatures in summer, the bicycle frame made of traditional epoxy resin may be deformed; skis in low-temperature environments in winter are prone to brittle fracture when using traditional epoxy resins. Although there have been studies on improving the performance of epoxy resins, most of them are only for high or low temperature environments, and epoxy resin compositions with excellent high and low temperature fracture toughness are still to be developed. Summary of the invention

[0004] In order to achieve the above purpose, this application is implemented through the following technical solutions: A resin composition with high and low temperature fracture properties is composed of the following raw materials in parts by weight: 30-50 parts of bisphenol A epoxy resin, 5-15 parts of carboxyl-terminated liquid nitrile rubber (CTBN), 10-25 parts of aromatic compounds, and 5-20 parts of fillers. Furthermore, the molecular weight of the carboxyl-terminated liquid nitrile rubber (CTBN) is 3000-5000 Da, and the carboxyl content is 0.5-2.0 mmol / g.

[0005] Furthermore, the aromatic compound is one or more combinations of m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, and bisphenol F epoxy resin.

[0006] Furthermore, the preparation method thereof comprises the following steps: Step 100, placing 30-50 parts of bisphenol A epoxy resin and 5-15 parts of carboxyl-terminated liquid nitrile rubber (CTBN) in a stirring container, stirring at 120-150° C. for 1-3 hours, and mixing well to obtain intermediate I; Step 200, adding 10-25 parts of an aromatic compound to the intermediate I, stirring at 80-120° C. for 2-4 hours, and mixing evenly to obtain the intermediate II; Step 300: Add fillers. Place 5 - 10 parts of intermediate II and 5 - 20 parts of fillers in another stirring container, stir at 60°C with a gradient rotation speed. After a preset time, add the intermediate II that was not used in step 200, and mix evenly to obtain intermediate III. Step 400: Cure and mold. Cast intermediate III into a mold, and cure it at 120 - 150°C for 4 - 8 h to finally obtain a resin composition with high and low temperature fracture toughness.

[0007] Further, in step 300, place 5 - 10 parts of intermediate II and 5 - 20 parts of fillers in another stirring container, and stir at 60°C with a gradient rotation speed. The gradient rotation speed is as follows: First, stir at a speed of 200 - 300 r / min for 15 - 30 min; then increase the speed to 500 - 700 r / min and stir for 20 - 40 min; finally, reduce the speed to 100 - 200 r / min and stir for 10 - 20 min.

[0008] Further, the resin composition with high and low temperature fracture toughness is applied in the field of sports equipment manufacturing, including bicycle frames, snowboards, badminton rackets, tennis rackets, and water sports equipment.

[0009] Compared with the prior art, the beneficial effects of this application are as follows: 1. In this application, the method of "toughening first and then strengthening" is adopted, that is, first, the carboxyl - terminated liquid nitrile rubber (CTBN) reacts with bisphenol A epoxy resin, and then an aromatic compound is added. The flexible chain segments are introduced through the pre - reaction of carboxyl - terminated liquid nitrile rubber (CTBN) and bisphenol A epoxy resin to solve the problem of low - temperature brittleness, and then the aromatic compound is used to cure to form a rigid cross - linked network, taking into account the high - temperature performance. 2. In this application, the fillers are pre - dispersed based on the gradient rotation speed, that is, through low - speed infiltration - high - speed dispersion - low - speed stabilization, the uniform dispersion of the fillers is achieved. This method does not require additional surface modifiers, and only by optimizing the process parameters, the dispersion of the fillers can be significantly improved, reducing costs while avoiding side reactions that may be brought about by chemical modification. It has the characteristics of simple process and strong universality. Description of the Drawings

[0010] Att Figure 1 is the process flow chart of this application. Detailed Embodiments

[0011] Combined with the drawings and specific embodiments, the present application is further described. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught in the present application, those skilled in the art can make various changes or modifications to the present application, and these equivalent forms also fall within the scope defined by the present application.

[0012] A resin composition with high and low temperature fracture toughness, which is composed of the following raw materials by weight, including: 30 - 50 parts of bisphenol A epoxy resin, 5 - 15 parts of carboxyl-terminated liquid nitrile rubber (CTBN), 10 - 25 parts of aromatic compounds, and 5 - 20 parts of fillers.

[0013] The molecular weight of the carboxyl-terminated liquid nitrile rubber (CTBN) is 3000 - 5000 Da, and the carboxyl content is 0.5 - 2.0 mmol / g; The aromatic compounds are one or more combinations of m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, and bisphenol F epoxy resin. Introducing aromatic structures into bisphenol A epoxy resin can improve the rigidity, heat resistance, and high-temperature fracture properties of the material. Compared with other aromatic compounds, m-phenylenediamine has a fast reaction rate and can form a cross-linked structure in a short time; 4,4'-diaminodiphenyl sulfone contains a sulfone group, and the sulfone group has strong electron-withdrawing properties, which can enhance the intermolecular force; bisphenol F epoxy resin contains two benzene rings and has stronger rigidity.

[0014] The fillers are one or more combinations of nano-silica, nano-alumina, carbon fiber, and boron nitride.

[0015] As Figure 1 shown, the preparation method of the above resin composition with high and low temperature fracture toughness includes the following steps: Step 100: Place 30 - 50 parts of bisphenol A epoxy resin and 5 - 15 parts of carboxyl-terminated liquid nitrile rubber (CTBN) in a stirring container, stir at 120 - 150 °C for 1 - 3 h, and after mixing evenly, obtain intermediate I; Step 200: Add 10 - 25 parts of aromatic compounds to intermediate I, stir at 80 - 120 °C for 2 - 4 h, and after mixing evenly, obtain intermediate II; Step 300: Add fillers. Place 5 - 10 parts of intermediate II and 5 - 20 parts of fillers in another stirring container, and stir at 60 °C with a gradient rotation speed. The gradient rotation speed means first stir at a speed of 200 - 300 r / min for 15 - 30 min; then increase the speed to 500 - 700 r / min and stir for 20 - 40 min; finally, reduce the speed to 100 - 200 r / min and stir for 10 - 20 min. Finally, add the intermediate II not used in step 200 and mix evenly to obtain intermediate III. In this application, a gradient rotation speed is adopted. By the method of low-speed infiltration - high-speed dispersion - low-speed stabilization, the aggregates in the fillers are broken up, so that the fillers are evenly distributed in the resin in a monodispersed state.

[0016] Step 400: Curing and molding. Cast intermediate Ⅲ into a mold and cure it at 120 - 150 °C for 4 - 8 h to finally obtain a resin composition with high and low temperature fracture toughness.

[0017] The resin composition with high and low temperature fracture toughness finally prepared by the above preparation method is applied in the field of sports equipment manufacturing, including bicycle frames, snowboards, badminton rackets, tennis rackets, and water sports equipment.

[0018] Sports equipment usually needs to have good toughness to withstand impacts and vibrations, and also requires a certain degree of rigidity and strength to ensure its performance. First, in this application, bisphenol A epoxy resin reacts with carboxyl-terminated liquid nitrile rubber (CTBN) first to form intermediate Ⅰ, and then reacts with aromatic compounds. The flexibility imparted to the resin composition by carboxyl-terminated liquid nitrile rubber (CTBN) can make sports equipment fit the human body better during use, providing a better feel and comfort. During the reaction process, the carboxyl groups at both ends of the carboxyl-terminated liquid nitrile rubber (CTBN) molecules have strong reactivity and can undergo ring-opening addition reactions with the epoxy groups in the epoxy resin. In this process, the hydrogen ion in the carboxyl group attacks the oxygen atom of the epoxy group, opening the epoxy ring and forming a new hydroxyl group. At the same time, the carboxyl-terminated liquid nitrile rubber (CTBN) molecules and bisphenol A epoxy resin molecules are connected together by chemical bonds. At the same time, the hydroxyl groups generated by the above ring-opening reaction can continue to react with the epoxy groups in the bisphenol A epoxy resin. This reaction causes the molecular chain to continuously grow and crosslink, gradually forming a three-dimensional network structure polymer, and the viscosity of the system gradually increases. Then the aromatic structure reacts with bisphenol A epoxy resin to further crosslink and cure to form a three-dimensional network structure. By pre-reacting carboxyl-terminated liquid nitrile rubber (CTBN) with bisphenol A epoxy resin to introduce flexible chain segments, the low-temperature brittleness problem is solved, and then using aromatic compounds to cure and form a rigid crosslinked network to balance the high-temperature performance. This sequence is different from traditional "single-component modification" or "synchronous blending", and is a targeted design for the complex environmental requirements of sports equipment, with clear application scenario specificity.

[0019] Secondly, by adding some functional fillers, such as nano-silica, carbon fiber, etc., they are uniformly distributed in Intermediate Ⅱ through a pre-dispersion process, and form a three-dimensional reinforcement network with carboxyl-terminated liquid nitrile rubber (CTBN) and aromatic compounds. Nano-fillers, such as nano-silica, nano-aluminum oxide, etc., enhance the interfacial adhesion with their high specific surface area; fiber fillers can provide structural support, and heat-conducting fillers such as boron nitride can accelerate heat dissipation. The synergy of carboxyl-terminated liquid nitrile rubber (CTBN), fillers, and aromatic compounds compensates for the slight impact of carboxyl-terminated liquid nitrile rubber (CTBN) on rigidity and heat resistance, achieving simultaneous improvement of mechanical properties and thermal properties. However, due to the large specific surface area and high surface energy of the fillers, they are prone to agglomeration with each other. When directly added to Intermediate Ⅱ, it is difficult to disperse uniformly, and filler agglomerates will be formed. These agglomerates will become stress concentration points of the resin composition. When the resin composition is subjected to external forces, cracks are likely to occur around the agglomerates, resulting in a decrease in the mechanical properties of the material. At the same time, if directly combined, the binding force between Intermediate Ⅱ and the fillers is weak, and the reinforcing effect cannot be fully exerted. In this application, a pre-dispersion process is adopted. First, the fillers are mixed with a part of Intermediate Ⅱ, and then mixed with the remaining unused Intermediate Ⅱ after a gradient rotation speed. Through a gradient rotation speed process of low-speed infiltration - high-speed dispersion - low-speed stabilization, the filler agglomerates are effectively broken, and the fillers are uniformly distributed in Intermediate Ⅱ in a monodispersed state, avoiding the problem of uneven dispersion of the fillers in a large amount of Intermediate Ⅱ, so as to improve the dispersion efficiency and effect of the fillers, and further better exert the reinforcing effect of the fillers on the material properties.

[0020] Example 1 A resin composition with high and low temperature fracture toughness is composed of the following raw materials in parts by weight, including: 30 parts of bisphenol A epoxy resin, 5 parts of carboxyl-terminated liquid nitrile rubber (CTBN), 10 parts of m-phenylenediamine, and 5 parts of nano-silica.

[0021] Among them, the molecular weight of the carboxyl-terminated liquid nitrile rubber (CTBN) is 3000 Da, and the carboxyl content is 0.5 mmol / g.

[0022] Its preparation method includes the following steps: Step 100, place 30 parts of bisphenol A epoxy resin and 5 parts of carboxyl-terminated liquid nitrile rubber (CTBN) in a stirring container, stir at 120 °C for 1 h, and obtain Intermediate Ⅰ after mixing evenly; Step 200, add 10 parts of m-phenylenediamine to Intermediate Ⅰ, stir at 80 °C for 2 h, and obtain Intermediate Ⅱ after mixing evenly; Step 300: Add fillers. Place 5 parts of Intermediate II and 5 parts of nano-silica in another stirring container, and stir at 60°C with a gradient rotation speed, that is, first stir at a speed of 20 r / min for 15 min; then increase the speed to 500 r / min and stir for 20 min; finally, reduce the speed to 100 r / min and stir for 10 min. Finally, add the Intermediate II not used in Step 200 and mix evenly to obtain Intermediate III; Step 400: Curing and molding. Cast Intermediate III into a mold and cure it at 120°C for 4 h to finally obtain a resin composition with high and low temperature fracture toughness.

[0023] In this application, the finally generated resin composition can be applied to the handles of badminton rackets and tennis rackets. The handles require good grip and impact resistance to cope with the vibration and collision during frequent hitting. The low temperature toughness of the resin composition can effectively buffer the impact force, and at the same time, the rigidity enhanced by nano-silica can ensure that the handle is not easily deformed during long-term use.

[0024] Example 2 A resin composition with high and low temperature fracture toughness is composed of the following raw materials in parts by weight, including: 40 parts of bisphenol A epoxy resin, 10 parts of carboxyl-terminated liquid nitrile rubber (CTBN), 15 parts of 4,4'-diaminodiphenyl sulfone, and 10 parts of nano-aluminum oxide.

[0025] Among them, the molecular weight of the carboxyl-terminated liquid nitrile rubber (CTBN) is 4000 Da, and the carboxyl content is 1 mmol / g.

[0026] Its preparation method includes the following steps: Step 100: Place 40 parts of bisphenol A epoxy resin and 10 parts of carboxyl-terminated liquid nitrile rubber (CTBN) in a stirring container and stir at 130°C for 2 h. After mixing evenly, obtain Intermediate I; Step 200: Add 15 parts of 4,4'-diaminodiphenyl sulfone to Intermediate I and stir at 90°C for 3 h. After mixing evenly, obtain Intermediate II; Step 300: Add fillers. Place 8 parts of Intermediate II and 10 parts of nano-aluminum oxide in another stirring container and stir at 60°C with a gradient rotation speed, that is, first stir at a speed of 250 r / min for 20 min; then increase the speed to 600 r / min and stir for 30 min; finally, reduce the speed to 150 r / min and stir for 15 min. Finally, add the Intermediate II not used in Step 200 and mix evenly to obtain Intermediate III. Cure it at 30°C for 6 h to finally obtain a resin composition with high and low temperature fracture toughness.

[0027] The finally produced resin composition in this application can be applied to bicycle frames. When a road bike is traveling at high speed, the frame needs to withstand large stresses and may face high-temperature environments. The high-temperature rigidity and heat resistance imparted by 4,4'-diaminodiphenyl sulfone and nano-aluminum oxide can ensure that the frame remains stable under different road conditions and climatic conditions. At the same time, the carboxyl-terminated liquid nitrile rubber (CTBN) can also provide a certain impact resistance.

[0028] Example 3 A resin composition with high and low temperature fracture toughness is composed of the following raw materials by weight, including: 50 parts of bisphenol A epoxy resin, 15 parts of carboxyl-terminated liquid nitrile rubber (CTBN), 25 parts of bisphenol F epoxy resin, and 20 parts of carbon fiber.

[0029] Among them, the carboxyl-terminated liquid nitrile rubber (CTBN) has a molecular weight of 5000 Da and a carboxyl content of 2.0 mmol / g.

[0030] Its preparation method includes the following steps: Step 100: Place 50 parts of bisphenol A epoxy resin and 15 parts of carboxyl-terminated liquid nitrile rubber (CTBN) in a stirring container, stir at 150 °C for 3 h, and after mixing evenly, obtain intermediate I; Step 200: Add 25 parts of bisphenol F epoxy resin to intermediate I, stir at 120 °C for 4 h, and after mixing evenly, obtain intermediate II; Step 300: Add fillers. Place 10 parts of intermediate II and 20 parts of carbon fiber in another stirring container, stir at 60 °C with a gradient speed, that is, first stir at a speed of 300 r / min for 30 min; then increase the speed to 700 r / min and stir for 40 min; finally, reduce the speed to 200 r / min and stir for 20 min. Finally, add the intermediate II not used in step 200 and mix evenly to obtain intermediate III; Step 400: Cure and mold. Pour intermediate III into a mold and cure at 150 °C for 8 h to finally obtain a resin composition with high and low temperature fracture toughness.

[0031] The finally produced resin composition in this application can be applied to snowboards.

[0032] Example 4 A resin composition with high and low temperature fracture toughness is composed of the following raw materials by weight, including: 35 parts of bisphenol A epoxy resin, 8 parts of carboxyl-terminated liquid nitrile rubber (CTBN), 12 parts of m-phenylenediamine as an aromatic compound, 8 parts of 4,4'-diaminodiphenyl sulfone, 12 parts of nano-silica and 8 parts of boron nitride as fillers.

[0033] Among them, the molecular weight of the carboxyl-terminated liquid nitrile rubber (CTBN) is 3500 Da, and the carboxyl content is 0.8 mmol / g.

[0034] Its preparation method includes the following steps: Step 100: Place 35 parts of bisphenol A epoxy resin and 8 parts of carboxyl-terminated liquid nitrile rubber (CTBN) in a stirring container, stir at 125 °C for 1.2 h, and obtain Intermediate I after mixing evenly. Step 200: Add 12 parts of m-phenylenediamine and 8 parts of 4,4'-diaminodiphenyl sulfone to Intermediate I, stir at 85 °C for 2.5 h, and obtain Intermediate II after mixing evenly. Step 300: Add fillers. Place 6 parts of Intermediate II, 12 parts of nano-silica, and 8 parts of boron nitride in another stirring container, and stir at 60 °C with a gradient speed, that is, first stir at a speed of 220 r / min for 18 min; then increase the speed to 550 r / min and stir for 25 min; finally, reduce the speed to 120 r / min and stir for 12 min. Finally, add the Intermediate II not used in Step 200 and mix evenly to obtain Intermediate III. Step 400: Cure and mold. Cast Intermediate III into a mold and cure at 125 °C for 5 h to finally obtain a resin composition with high and low temperature fracture toughness.

[0035] The finally prepared resin composition in this application can be applied to water sports equipment.

[0036] Example 5 A resin composition with high and low temperature fracture toughness is composed of the following raw materials by weight, including: 45 parts of bisphenol A epoxy resin, 12 parts of carboxyl-terminated liquid nitrile rubber (CTBN), 18 parts of bisphenol F epoxy resin as an aromatic compound, 7 parts of m-phenylenediamine, and 15 parts of nano-aluminum oxide and 5 parts of carbon fiber as fillers.

[0037] Among them, the molecular weight of the carboxyl-terminated liquid nitrile rubber (CTBN) is 4500 Da, and the carboxyl content is 1.5 mmol / g.

[0038] Its preparation method includes the following steps: Step 100: Place 45 parts of bisphenol A epoxy resin and 12 parts of carboxyl-terminated liquid nitrile rubber (CTBN) in a stirring container, stir at 140 °C for 2.5 h, and obtain Intermediate I after mixing evenly. Step 200: Add an aromatic compound to Intermediate I and stir at 110 °C for 3.5 h to obtain Intermediate II after mixing evenly. Step 300: Add fillers. Place 7 parts of intermediate II, 15 parts of nano-aluminum oxide, and 5 parts of carbon fiber in another stirring container, and stir at 60 °C with a gradient rotation speed, that is, first stir at a speed of 280 r / min for 25 min; then increase the speed to 650 r / min and stir for 35 min; finally, reduce the speed to 180 r / min and stir for 18 min. Finally, add the intermediate II that was not used in step 200 and mix evenly to obtain intermediate III. Step 400: Curing and molding. Cast intermediate III into a mold and cure it at 140 °C for 7 h to finally obtain a resin composition with high and low temperature fracture toughness.

[0039] The finally prepared resin composition in this application can be applied to a bicycle frame.

[0040] Performance Test Perform high-temperature and low-temperature performance tests on the resin compositions obtained in Examples 1-5, and the results are shown in Table 1.

[0041] Table 1

[0042] It can be seen from Table 1 that when the resin composition is kept in an environment of 150 °C for 2 hours, the tensile strength retention rates of Examples 1-6 all exceed 90%, indicating that the resin composition in this application has stronger structural stability at high temperatures; the elongation at break retention rate also performs excellently, maintaining above 85%, ensuring that the material still has a certain toughness at high temperatures. At the same time, when the resin composition is in an environment of -40 °C, the impact strength of the resin compositions in Examples 1-5 is all above 30 kJ / m², showing excellent low-temperature impact resistance. The glass transition temperature is between 135-145 °C, proving that the heat resistance of the material has been improved and it can withstand higher temperatures without significant softening. The flexural strength and hardness also reflect the synergistic effect of the fillers, enhancing the rigidity and wear resistance.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A resin composition with high and low temperature fracture toughness, characterized in that: It is composed of the following raw materials in parts by weight: 30-50 parts of bisphenol A epoxy resin, 5-15 parts of liquid carboxyl-terminated nitrile rubber, 10-25 parts of aromatic compound, and 5-20 parts of filler.

2. The resin composition with high and low temperature fracture toughness according to claim 1, characterized in that: The molecular weight of the liquid carboxyl-terminated nitrile rubber is 3000-5000 Da, and the carboxyl content is 0.5-2.0 mmol / g.

3. The resin composition with high and low temperature fracture toughness according to claim 1, characterized in that: The aromatic compound is one or a combination of m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, and bisphenol F type epoxy resin.

4. The resin composition with high and low temperature fracture toughness according to claim 1, characterized in that: The filler is one or a combination of nano-silica, nano-aluminum oxide, carbon fiber, and boron nitride.

5. The resin composition with high and low temperature fracture toughness according to claim 1, characterized in that: Its preparation method includes the following steps: Step 100: Place 30-50 parts of bisphenol A epoxy resin and 5-15 parts of liquid carboxyl-terminated nitrile rubber in a stirring container, stir at 120-150 °C for 1-3 h, and after mixing evenly, obtain intermediate I; Step 200: Add 10-25 parts of aromatic compound to intermediate I, stir at 80-120 °C for 2-4 h, and after mixing evenly, obtain intermediate II; Step 300: Add the filler. Place 5-10 parts of intermediate II and 5-20 parts of filler in another stirring container, stir at 60 °C at a gradient speed. After a preset time, add the intermediate II not used in step 200, and mix evenly to obtain intermediate III; Step 400: Cure and mold. Pour intermediate III into a mold, cure at 120-150 °C for 4-8 h, and finally obtain a resin composition with high and low temperature fracture toughness.

6. The resin composition with high and low temperature fracture toughness according to claim 5, characterized in that: In step 300, place 5-10 parts of intermediate II and 5-20 parts of filler in another stirring container, stir at 60 °C at a gradient speed. The gradient speed is that first stir at a speed of 200-300 r / min for 15-30 min; then increase the speed to 500-700 r / min and stir for 20-40 min; finally, reduce the speed to 100-200 r / min and stir for 10-20 min.

7. An application of the resin composition with high and low temperature fracture toughness according to any one of claims 1-6.

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