A single-component low-expansion coefficient paste adhesive for bonding carbon fiber composite materials and a preparation method thereof

Abstract

The application relates to a single-component low-expansion coefficient paste adhesive for bonding carbon fiber composite materials and a preparation method thereof. The application aims to solve the problem that the strength of the adhesive for bonding the composite materials is greatly reduced after the thermal expansion coefficient of the adhesive is reduced. The single-component low-expansion coefficient paste adhesive for bonding carbon fiber composite materials is prepared from 30-50 parts of phenolic hydroxyl polyphenyl ether resin modified glass fiber powder, 70-90 parts of bisphenol A type epoxy resin, 10-30 parts of multifunctional epoxy resin, 5-20 parts of carboxyl-terminated liquid butyronitrile rubber, 5-20 parts of polyether oligomer, 11-15 parts of modified dicyandiamide and 2-4 parts of fumed white carbon black. The thermal expansion coefficient (<Tg) of the single-component low-expansion coefficient paste adhesive for bonding carbon fiber composite materials prepared by the application is (30.2-42.7) mu m / (m*deg C).

Description

Technical Field

[0001] This invention relates to an adhesive and its preparation method. Background Technology

[0002] Carbon fiber composites are high-strength materials composed of carbon fibers and resin. Because carbon fibers have high modulus and tensile strength, they can withstand large loads, resulting in higher strength and rigidity in carbon fiber composites. Carbon fiber composites have a specific gravity only one-quarter that of steel, yet their strength is more than ten times that of steel. Furthermore, carbon fiber composites possess excellent corrosion resistance and a low coefficient of thermal expansion. Due to their good formability and plasticity, carbon fiber composites offer high design freedom and are often used in fields with special requirements, such as aerospace, the automotive industry, and sporting goods.

[0003] Adhesive bonding is a commonly used joining technology for carbon fiber composite materials. Epoxy resin adhesives are generally the most widely used adhesives because they have high bonding strength, simple processing, do not affect the strength of the substrate laminate, and have advantages such as fatigue resistance, sealing and vibration reduction, no electrochemical corrosion, and no stress concentration.

[0004] The coefficient of thermal expansion (CTE) of a pure epoxy resin system is generally (50–60) μm / (m·℃). After adding toughening agents such as liquid rubber to prepare an adhesive, the CTE increases to (80–100) μm / (m·℃) with increasing toughening agent content. When using epoxy adhesives to bond carbon fiber composites with low CTEs in environments with large temperature variations, internal stress can easily develop, which can severely affect bond strength and the dimensional accuracy of the bonded materials. Therefore, when bonding some precision carbon fiber composite structures, adhesives with low CTEs are required to achieve good dimensional accuracy and bonding reliability.

[0005] Adding inorganic fillers such as zirconium tungstate, alumina, and quartz powder can effectively reduce the coefficient of thermal expansion of adhesives. However, the adhesive strength decreases significantly after adding such fillers, with the shear strength reduced to (14-17) MPa. Summary of the Invention

[0006] The purpose of this invention is to solve the problem that the strength of bonded composite materials decreases significantly after reducing the coefficient of thermal expansion of existing adhesives, and to provide a single-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials and its preparation method.

[0007] A one-component paste adhesive with low coefficient of thermal expansion for bonding carbon fiber composites is prepared from 30 to 50 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 to 90 parts by weight of bisphenol A epoxy resin, 10 to 30 parts by weight of polyfunctional epoxy resin, 5 to 20 parts by weight of carboxyl-terminated liquid nitrile rubber, 5 to 20 parts by weight of polyether oligomer, 11 to 15 parts by weight of modified dicyandiamide, and 2 to 4 parts by weight of fumed silica.

[0008] A preparation method of a one-component paste adhesive with low coefficient of thermal expansion for bonding carbon fiber composites is specifically completed according to the following steps:

[0009] I. Weighing:

[0010] Weigh 30 to 50 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 to 90 parts by weight of bisphenol A epoxy resin, 10 to 30 parts by weight of polyfunctional epoxy resin, 5 to 20 parts by weight of carboxyl-terminated liquid nitrile rubber, 5 to 20 parts by weight of polyether oligomer, 11 to 15 parts by weight of modified dicyandiamide, and 2 to 4 parts by weight of fumed silica according to the parts by weight;

[0011] II. Mixing:

[0012] Add the 30 to 50 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 to 90 parts by weight of bisphenol A epoxy resin, 10 to 30 parts by weight of polyfunctional epoxy resin, 5 to 20 parts by weight of carboxyl-terminated liquid nitrile rubber, 5 to 20 parts by weight of polyether oligomer, 11 to 15 parts by weight of modified dicyandiamide, and 2 to 4 parts by weight of fumed silica weighed in step I into a reactor, stir and mix to obtain a mixture;

[0013] III. Grinding:

[0014] Use a three-roll mill to grind the mixture to obtain a one-component paste adhesive, which is the one-component paste adhesive with low coefficient of thermal expansion for bonding carbon fiber composites.

[0015] Advantages of the present invention:

[0016] The curing conditions of the one-component paste adhesive with low coefficient of thermal expansion for bonding carbon fiber composites prepared by the present invention are 120 °C / 90 min, the glass transition temperature Tg is 139 °C to 145 °C, the coefficient of thermal expansion (<Tg) is (30.2 - 42.7) μm / (m·°C), and the room temperature shear strength of bonding carbon fiber / epoxy composites is (25.6 - 27.3) MPa. Description of the drawings

[0017] Figure 1 It is the TMA curve of the adhesive system without adding phenolic hydroxyl polyphenylene ether resin modified glass fiber powder in Comparative Example 2;

[0018] Figure 2 The TMA curve is shown for the glass fiber powder adhesive system modified with phenolic hydroxyl polyphenylene ether resin in Example 2. Detailed Implementation

[0019] Specific Implementation Method 1: This implementation method provides a single-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials, prepared by weight of 30-50 parts phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70-90 parts bisphenol A type epoxy resin, 10-30 parts multifunctional epoxy resin, 5-20 parts carboxyl-terminated liquid nitrile rubber, 5-20 parts polyether oligomer, 11-15 parts modified dicyandiamide, and 2-4 parts fumed silica.

[0020] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the preparation method of the phenolic hydroxyl polyphenylene ether resin modified glass fiber powder is specifically prepared according to the following steps:

[0021] 1. Weigh out 100 parts solvent, 10 parts glass fiber powder, and 0.1 to 0.5 parts phenolic hydroxyl polyphenylene ether resin by weight.

[0022] 2. Add 100 parts of solvent, 10 parts of glass fiber powder and 0.1 to 0.5 parts of phenolic hydroxyl polyphenylene ether resin to the reactor, and then sonicate the mixture for 1 to 2 hours at room temperature using an ultrasonic disperser with an ultrasonic power of 500W to 1000W to obtain the product.

[0023] 3. Filter the product, dry the solid product at 50℃~60℃ for 3h~5h, and grind it to obtain phenolic hydroxyl polyphenylene ether resin modified glass fiber powder. Other steps are the same as in specific embodiment one.

[0024] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the glass fiber powder mentioned in step one is alkali-free glass fiber; the monofilament diameter of the glass fiber is 13μm to 17μm, and the average length is 200μm. Other steps are the same as in Specific Implementation Method One or Two.

[0025] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the molecular weight of the phenolic hydroxyl polyphenylene ether resin mentioned in step one is 1600-2000; the hydroxyl equivalent of the phenolic hydroxyl polyphenylene ether resin is 750 g / mol-850 g / mol; the type of the phenolic hydroxyl polyphenylene ether resin is SA90, purchased from Saudi Basic Industries Corporation (SABIC); and the solvent mentioned in step one is toluene or methyl ethyl ketone. Other steps are the same as in Specific Implementation Methods One to Three.

[0026] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the bisphenol A type epoxy resin used is E44, E51, or E54. The other steps are the same as in Specific Implementation Methods One to Four.

[0027] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the multifunctional epoxy resin used is AG-80, AG-70, or AFG-90. The other steps are the same as in Specific Implementation Methods One to Five.

[0028] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: the acrylonitrile content of the carboxyl-terminated liquid nitrile rubber is 10% to 28%; the molecular weight of the carboxyl-terminated liquid nitrile rubber is 3000 to 4000; and the type of the carboxyl-terminated liquid nitrile rubber is CTBN 1300X13 or CTBN 1300X31, purchased from Huntsman Corporation. The other steps are the same as in Specific Implementation Methods One to Six.

[0029] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the preparation method of the polyether oligomer is specifically completed according to the following steps:

[0030] Add 2000g of polyetheramine D-2000 and 200g-500g of alkyl glycidyl ether to a reactor. Under the condition of stirring speed of 500r / min-600r / min, the temperature is increased from room temperature to 60℃-80℃ at a heating rate of 2℃ / min-5℃ / min. Stir continuously at 60℃-80℃ for 3h-4h to obtain polyether oligomer.

[0031] The alkyl glycidyl ether is one of C8 to C10 alkyl glycidyl ether or C12 to C14 alkyl glycidyl ether. Other steps are the same as in specific embodiments one to seven.

[0032] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the modified dicyandiamide is EH-3842; and the fumed silica is one of LM-150, M-5, and H-300. The other steps are the same as in Specific Implementation Methods One to Eight.

[0033] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that it involves the following steps: A method for preparing a single-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials.

[0034] I. Weighing materials:

[0035] Weigh out 30-50 parts of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70-90 parts of bisphenol A type epoxy resin, 10-30 parts of multifunctional epoxy resin, 5-20 parts of carboxyl-terminated liquid nitrile rubber, 5-20 parts of polyether oligomer, 11-15 parts of modified dicyandiamide and 2-4 parts of fumed silica by weight.

[0036] II. Mixing:

[0037] Add 30-50 parts of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70-90 parts of bisphenol A type epoxy resin, 10-30 parts of multifunctional epoxy resin, 5-20 parts of carboxyl-terminated liquid nitrile rubber, 5-20 parts of polyether oligomer, 11-15 parts of modified dicyandiamide and 2-4 parts of fumed silica weighed in step one to the reactor, stir and mix to obtain a mixture;

[0038] III. Grinding:

[0039] The mixture is ground using a three-roll mill to obtain a one-component paste adhesive, which is a one-component low expansion coefficient paste adhesive for bonding carbon fiber composite materials. Other steps are the same as in embodiments one through nine.

[0040] The beneficial effects of the present invention are verified using the following embodiments:

[0041] Example 1: A method for preparing a one-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composites, specifically comprising the following steps:

[0042] I. Weighing materials:

[0043] Weigh out 50 parts of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 parts of bisphenol A type epoxy resin, 30 parts of multifunctional epoxy resin, 10 parts of carboxyl-terminated liquid nitrile rubber, 10 parts of polyether oligomer, 15 parts of modified dicyandiamide and 3 parts of fumed silica by weight.

[0044] The bisphenol A type epoxy resin mentioned in step one is E51;

[0045] The multifunctional epoxy resin mentioned in step one is AG-80;

[0046] The acrylonitrile content of the carboxyl-terminated liquid nitrile rubber mentioned in step one is 10%;

[0047] The molecular weight of the carboxyl-terminated liquid nitrile rubber mentioned in step one is 3800;

[0048] The carboxyl-terminated liquid nitrile rubber mentioned in step one is CTBN 1300X31, purchased from Huntsman.

[0049] The method for preparing the polyether oligomer described in step one is specifically carried out according to the following steps:

[0050] 2000g of polyetheramine D-2000 and 400g of alkyl glycidyl ether were added to a reactor. The temperature was increased from room temperature to 70°C at a rate of 2°C / min under a stirring speed of 500r / min. The mixture was stirred continuously at 70°C for 3h to obtain a polyether oligomer. The alkyl glycidyl ether was a C8 to C10 alkyl glycidyl ether.

[0051] The modified dicyandiamide mentioned in step one is EH-3842; the fumed silica mentioned is M-5;

[0052] II. Mixing:

[0053] Add 50 parts of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 parts of bisphenol A type epoxy resin, 30 parts of multifunctional epoxy resin, 10 parts of carboxyl-terminated liquid nitrile rubber, 10 parts of polyether oligomer, 15 parts of modified dicyandiamide and 3 parts of fumed silica weighed in step one to the reactor, stir and mix to obtain a mixture.

[0054] III. Grinding:

[0055] The mixture was ground using a three-roll mill to obtain a one-component paste adhesive, which is a one-component low expansion coefficient paste adhesive for bonding carbon fiber composite materials.

[0056] The preparation method of the phenolic hydroxyl polyphenylene ether resin modified glass fiber powder described in step one is specifically as follows:

[0057] ① Weigh out 100 parts solvent, 10 parts glass fiber powder and 0.3 parts phenolic hydroxyl polyphenylene ether resin by weight.

[0058] The glass fiber powder mentioned in step ① is alkali-free glass fiber; the diameter of the single filament of the glass fiber is 13μm to 17μm, and the average length is 200μm;

[0059] The phenolic hydroxyl polyphenylene ether resin mentioned in step ① has a molecular weight of 1800; the hydroxyl equivalent of the phenolic hydroxyl polyphenylene ether resin is 840 g / mol; the phenolic hydroxyl polyphenylene ether resin is of type SA90 and was purchased from Saudi Basic Industries Corporation (SABIC).

[0060] The solvent mentioned in step ① is toluene;

[0061] ② Add 100 parts solvent, 10 parts glass fiber powder and 0.3 parts phenolic hydroxyl polyphenylene ether resin to the reactor, and then sonicate the mixture for 1 hour at room temperature using an ultrasonic disperser with an ultrasonic power of 1000W to obtain the product.

[0062] ③ The product is filtered, the solid product is dried at 60℃ for 4 hours, and then ground to obtain phenolic hydroxyl polyphenylene ether resin modified glass fiber powder.

[0063] Comparative Example 1: The difference between this example and Example 1 is that in step one, 0 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 parts of bisphenol A type epoxy resin, 30 parts of multifunctional epoxy resin, 10 parts of carboxyl-terminated liquid nitrile rubber, 10 parts of polyether oligomer, 15 parts of modified dicyandiamide, and 3 parts of fumed silica are weighed. All other steps and parameters are the same as in Example 1.

[0064] Example 2: The difference between this example and Example 1 is that in step one, 50 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 parts of bisphenol A type epoxy resin, 30 parts of multifunctional epoxy resin, 20 parts of carboxyl-terminated liquid nitrile rubber, 20 parts of polyether oligomer, 15 parts of modified dicyandiamide, and 3 parts of fumed silica are weighed. All other steps and parameters are the same as in Example 1.

[0065] Comparative Example 2: The difference between this example and Example 2 is that in step one, 0 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 parts of bisphenol A type epoxy resin, 30 parts of multifunctional epoxy resin, 20 parts of carboxyl-terminated liquid nitrile rubber, 20 parts of polyether oligomer, 15 parts of modified dicyandiamide, and 3 parts of fumed silica are weighed. All other steps and parameters are the same as in Example 2.

[0066] Example 3: The difference between this example and Example 1 is that in step one, 30 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 parts of bisphenol A type epoxy resin, 30 parts of multifunctional epoxy resin, 10 parts of carboxyl-terminated liquid nitrile rubber, 10 parts of polyether oligomer, 15 parts of modified dicyandiamide, and 3 parts of fumed silica are weighed. All other steps and parameters are the same as in Example 1.

[0067] Comparative Example 3: The difference between this example and Example 3 is that in step one, 0 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70 parts of bisphenol A type epoxy resin, 30 parts of multifunctional epoxy resin, 10 parts of carboxyl-terminated liquid nitrile rubber, 10 parts of polyether oligomer, 15 parts of modified dicyandiamide, and 3 parts of fumed silica are weighed. All other steps and parameters are the same as in Example 3.

[0068] The room temperature shear strength and coefficient of thermal expansion of the carbon fiber / epoxy composite materials bonded using the adhesives prepared in Example 1 and Comparative Example 1 are shown in Table 1.

[0069] Table 1. Room temperature shear strength and coefficient of thermal expansion of the adhesives prepared in Example 1 and Control Example 1.

[0070]

[0071] The room-temperature shear strength and coefficient of thermal expansion of the carbon fiber / epoxy composite bonded with the adhesives prepared in Example 2 and Comparative Example 2 are shown in Table 2.

[0072] Table 2 Data of the room-temperature shear strength and coefficient of thermal expansion of the adhesives prepared in Example 2 and Comparative Example 2

[0073]

[0074]

[0075] The room-temperature shear strength and coefficient of thermal expansion of the carbon fiber / epoxy composite bonded with the adhesives prepared in Example 3 and Comparative Example 3 are shown in Table 3.

[0076] Table 3 Data of the room-temperature shear strength and coefficient of thermal expansion of the adhesives prepared in Example 3 and Comparative Example 3

[0077]

[0078] The phenolic hydroxyl group-containing polyphenylene ether resin-modified glass fiber powder in the present invention has good dispersion performance in the epoxy resin adhesive, with a moderate particle size, stable storage, and no sedimentation; after addition, it can effectively reduce the coefficient of thermal expansion of the adhesive and has excellent bonding strength for carbon fiber composites, solving the problem that the bonding strength of the adhesive for composite materials decreases significantly after adding inorganic fillers.

[0079] Figure 1 It is the TMA curve of the adhesive system without adding phenolic hydroxyl group-containing polyphenylene ether resin-modified glass fiber powder in Comparative Example 2;

[0080] Figure 2 It is the TMA curve of the adhesive system with adding phenolic hydroxyl group-containing polyphenylene ether resin-modified glass fiber powder in Example 2.

[0081] From Figure 1 it can be obtained that: the glass transition temperature Tg of the adhesive is 140 °C; the coefficient of thermal expansion (<Tg) is 134.7 μm / (m·°C).

[0082] From Figure 2 it can be obtained that the glass transition temperature Tg of the adhesive is 140 °C; the coefficient of thermal expansion (

Claims

1. A one-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials, characterized in that... The adhesive is prepared by weight of 30-50 parts phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70-90 parts bisphenol A type epoxy resin, 10-30 parts multifunctional epoxy resin, 5-20 parts carboxyl-terminated liquid nitrile rubber, 5-20 parts polyether oligomer, 11-15 parts modified dicyandiamide and 2-4 parts fumed silica; The modified dicyandiamide is EH-3842; The preparation method of the phenolic hydroxyl polyphenylene ether resin modified glass fiber powder is specifically carried out according to the following steps:

1. Weigh out 100 parts solvent, 10 parts glass fiber powder, and 0.1 to 0.5 parts phenolic hydroxyl polyphenylene ether resin by weight.

2. Add 100 parts of solvent, 10 parts of glass fiber powder and 0.1 to 0.5 parts of phenolic hydroxyl polyphenylene ether resin to the reactor, and then sonicate the mixture for 1 to 2 hours at room temperature using an ultrasonic disperser with an ultrasonic power of 500W to 1000W to obtain the product.

3. Filter the product, dry the solid product at 50℃~60℃ for 3h~5h, and grind it to obtain phenolic hydroxyl polyphenylene ether resin modified glass fiber powder. The preparation method of the polyether oligomer is specifically carried out according to the following steps: Add 2000g of polyetheramine D-2000 and 200g~500g of alkyl glycidyl ether to the reactor. Under the condition of stirring speed of 500r / min~600r / min, the temperature is increased from room temperature to 60℃~80℃ at a heating rate of 2℃ / min~5℃ / min. Stir continuously at 60℃~80℃ for 3h~4h to obtain polyether oligomer. The alkyl glycidyl ether is one of C8 to C10 alkyl glycidyl ether or C12 to C14 alkyl glycidyl ether.

2. The single-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials according to claim 1, characterized in that... The glass fiber powder mentioned in step one is alkali-free glass fiber; the diameter of the single filament of the glass fiber is 13μm~17μm, and the average length is 200μm.

3. The single-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials according to claim 1, characterized in that... The molecular weight of the phenolic hydroxyl polyphenylene ether resin mentioned in step one is 1600~2000; the hydroxyl equivalent of the phenolic hydroxyl polyphenylene ether resin is 750g / mol~850g / mol; and the solvent mentioned in step one is toluene or methyl ethyl ketone.

4. The single-component low expansion coefficient paste adhesive for bonding carbon fiber composite materials according to claim 1, characterized in that... The fumed silica is one of LM-150, M-5, and H-300.

5. The single-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials according to claim 1, characterized in that... The bisphenol A type epoxy resin is E44, E51 or E54.

6. The single-component, low-expansion-coefficient paste adhesive for bonding carbon fiber composite materials according to claim 1, characterized in that... The multifunctional epoxy resin is AG-80, AG-70 or AFG-90.

7. The single-component low expansion coefficient paste adhesive for bonding carbon fiber composite materials according to claim 1, characterized in that... The acrylonitrile content of the terminal carboxyl liquid nitrile rubber is 10%~28%; the molecular weight of the terminal carboxyl liquid nitrile rubber is 3000~4000.

8. The method for preparing a single-component low-expansion coefficient paste adhesive for bonding carbon fiber composites as described in claim 1, characterized in that... The preparation method is specifically carried out according to the following steps: I. Weighing materials: Weigh out 30-50 parts by weight of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70-90 parts by weight of bisphenol A type epoxy resin, 10-30 parts by weight of multifunctional epoxy resin, 5-20 parts by weight of carboxyl-terminated liquid nitrile rubber, 5-20 parts by weight of polyether oligomer, 11-15 parts by weight of modified dicyandiamide and 2-4 parts by weight of fumed silica; II. Mixing: Add 30-50 parts of phenolic hydroxyl polyphenylene ether resin modified glass fiber powder, 70-90 parts of bisphenol A type epoxy resin, 10-30 parts of multifunctional epoxy resin, 5-20 parts of carboxyl-terminated liquid nitrile rubber, 5-20 parts of polyether oligomer, 11-15 parts of modified dicyandiamide and 2-4 parts of fumed silica weighed in step one to the reactor, stir and mix to obtain a mixture; III. Grinding: The mixture is ground using a three-roll mill to obtain a one-component paste adhesive, which is a one-component low expansion coefficient paste adhesive for bonding carbon fiber composite materials.

Images