Rubber pad, composite rubber pad and preparation method and application thereof, and autoclave resin prepreg forming method

Abstract

The invention belongs to the technical field of resin prepreg forming, and particularly relates to a rubber pad, a composite rubber pad, a preparation method and application of the composite rubber pad, and an autoclave resin prepreg forming method. The rubber pad comprises the following raw materials in parts by weight: 70-100 parts of synthetic rubber, 10-50 parts of silicon dioxide, 30-80 parts of carbon black, 10-50 parts of filler, 5-15 parts of operating oil, 0.5-5 parts of stearic acid, 1-10 parts of zinc oxide, 0.1-2 parts of an anti-aging agent and 2-10 parts of sulfur-containing phenolic resin. The rubber pad provided by the invention is used for molding an autoclave composite material, the vulcanized rubber pressure pad provides pressure by utilizing the self weight of the material, and the rubber pressure pad is good in fitness, can be well attached to a product, can conduct the pressure to the surface of a workpiece, and can provide enough pressure when a resin prepreg is cured, so that the service life of the product is prolonged, and the service life of the product is prolonged. Therefore, the interlayer of the resin prepreg is tighter, and the product defect caused by bridging of the auxiliary material in the curing process is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of resin prepreg molding, and in particular relates to a rubber pad, a composite rubber pad, a preparation method and application thereof, and a method for molding resin prepreg in an autoclave. Background Art

[0002] An autoclave is a device used for high temperature and high pressure processes and is commonly used in the production of composite materials. It can hot-press resin prepregs under high temperature and high pressure to obtain the desired shape and properties.

[0003] In the autoclave molding process of resin prepreg, the shape of the mold varies greatly, especially for more complex molds or larger molds, which have a large number of protrusions and grooves. This makes it possible for auxiliary materials such as release cloth, isolation film, breathable felt and vacuum bag film to be laid out in a manner that does not necessarily fit the shape of the mold tightly, but may form bridges, resulting in the pressure applied by the autoclave being unable to be transmitted to the surface of the resin prepreg, resulting in poor interlayer bonding of the resin prepreg and the presence of a large number of gaps, which affects the performance of the resin prepreg parts. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a rubber pad, a composite rubber pad, a preparation method and application thereof, and a method for autoclave resin prepreg molding. The rubber pad of the present invention is used for autoclave resin prepreg molding, and the pressure is easily transmitted to the surface of the workpiece, which can provide sufficient pressure when the resin prepreg is cured, so that the layers of the resin prepreg are more compact, avoiding product defects caused by bridging of auxiliary materials during the curing process.

[0005] The invention provides a rubber pad, comprising the following raw materials in parts by weight: 70-100 parts of synthetic rubber, 10-50 parts of silicon dioxide, 30-80 parts of carbon black, 10-50 parts of filler, 5-15 parts of operating oil, 0.5-5 parts of stearic acid, 1-10 parts of zinc oxide, 0.1-2 parts of antioxidant and 2-10 parts of sulfur-containing phenolic resin.

[0006] Preferably, the thickness of the rubber pad is 0.3-2.5 mm.

[0007] Preferably, the synthetic rubber includes one or more of butyl rubber, chlorinated butyl rubber, brominated butyl rubber, butadiene rubber, nitrile rubber, chloroprene rubber, ethylene propylene rubber and ethylene propylene diene monomer rubber.

[0008] The present invention also provides a method for preparing the rubber pad described in the above technical solution, comprising the following steps:

[0009] After the synthetic rubber is plasticized, it is mixed with silicon dioxide, carbon black, filler, process oil and stearic acid for a first banburying to obtain a mixture;

[0010] The mixed material, zinc oxide, antioxidant and sulfur-containing phenolic resin are mixed and kneaded for a second time to obtain a raw rubber compound;

[0011] The raw rubber material is extruded and calendered to obtain a rubber pad.

[0012] Preferably, the temperature of the first banburying is 100-120° C., and the time is 15-25 minutes.

[0013] Preferably, the temperature of the second kneading is 50-60° C., and the time is 3-5 minutes.

[0014] The present invention also provides a composite rubber pad, which comprises stacked rubber pads, and a temperature sensor and / or an electric heating device arranged between the rubber pad layers;

[0015] The rubber pad is the rubber pad described in the above technical solution or the rubber pad obtained by the above preparation method.

[0016] The present invention also provides the use of the rubber pad or the composite rubber pad described in the above technical solution in the autoclave resin prepreg molding.

[0017] The present invention also provides a method for forming an autoclave resin prepreg, comprising the following steps:

[0018] vulcanizing the rubber pad or composite rubber pad described in the above technical solution in a mold to obtain a rubber pressure pad or a composite rubber pressure pad;

[0019] The resin prepreg is placed in the mold, and a release cloth, the rubber pressure pad or the composite rubber pressure pad, an isolation film, and a breathable felt are placed on the prepreg in sequence, and the prepreg is cured in an autoclave to obtain a molding material.

[0020] Preferably, the vulcanization temperature is 160-200° C. and the vulcanization time is 120-180 minutes.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The invention provides a rubber pad, comprising the following raw materials in parts by weight: 70-100 parts of synthetic rubber, 10-50 parts of silicon dioxide, 30-80 parts of carbon black, 10-50 parts of filler, 5-15 parts of operating oil, 0.5-5 parts of stearic acid, 1-10 parts of zinc oxide, 0.1-2 parts of antioxidant and 2-10 parts of sulfur-containing phenolic resin.

[0023] The rubber pad of the present invention is used for hot-press composite material molding. After the rubber pad is vulcanized, it is laid on the demoulding cloth of the hot-press, and the weight of the material itself is used to provide pressure. The rubber pad has good conformability and can fit the product well. It can transmit the pressure to the surface of the workpiece, and can provide sufficient pressure when the resin prepreg is cured, so that the layers of the resin prepreg are more compact, avoiding product defects caused by bridging of auxiliary materials during the curing process.

[0024] The present invention also provides a composite rubber pad, comprising a rubber pad arranged in a stacked manner, and a temperature sensor and / or an electric heating device arranged between the rubber pad layers. The autoclave is usually composed of a tank body, a temperature control system, a pressure control system, etc., and is equipped with a temperature sensor for monitoring and maintaining the temperature of the working area. The temperature control system will automatically switch the heater on and off to maintain a certain working temperature according to the set temperature value and the monitored temperature, but the temperature monitoring is mainly achieved by the air thermocouple on the equipment and the thermocouple arranged on the mold surface, and the temperature during the molding of the resin prepreg cannot be monitored. Due to the different shapes of the molds and the different placement positions in the autoclave, there is a certain temperature difference between different areas, which may cause the curing degree of the resin prepreg to be different, and ultimately cause inconsistent material performance. The composite rubber pad of the present invention can be matched with temperature control components such as a thermocouple thermometer and a polyimide heating film, and the thermocouple and the heating film are arranged between the two layers of rubber pads, and connected to the thermocouple thermometer, thereby playing a role in real-time monitoring of the surface temperature of the resin prepreg, which is more accurate than the temperature of the air thermocouple of the autoclave and the thermocouple on the mold surface. When there is uneven temperature, local heating compensation can be performed through the temperature meter controller, thereby improving the consistency of the curing degree of the resin prepreg product.

[0025] The data of the embodiment show that the pressure pad of the present invention is used for hot-press composite material molding after vulcanization. The rubber pressure pad has excellent aging resistance and can still play the effect of pressure transmission after repeated use, and has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is the thermal weight loss curve of the rubber pressure pad of Example 2;

[0028] Figure 2 The following are photos of the flat plate and special-shaped mold sample preparation of the composite rubber pressure pad in Example 4;

[0029] Figure 3 This is an exploded view of the implementation steps of arranging the thermocouple and the heating film in Example 4;

[0030] Figure 4 A comparison chart of samples made with and without the rubber pressure pad of Example 3. DETAILED DESCRIPTION

[0031] The invention provides a rubber pad, comprising the following raw materials in parts by weight: 70-100 parts of synthetic rubber, 10-50 parts of silicon dioxide, 30-80 parts of carbon black, 10-50 parts of filler, 5-15 parts of operating oil, 0.5-5 parts of stearic acid, 1-10 parts of zinc oxide, 0.1-2 parts of antioxidant and 2-10 parts of sulfur-containing phenolic resin.

[0032] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0033] In the present invention, the thickness of the rubber pad is preferably 0.3-2.5 mm, specifically 1.6 mm; the width of the rubber pad is preferably 0.9-1.5 m, specifically 1.1 m.

[0034] In the present invention, the synthetic rubber preferably includes one or more of butyl rubber, chlorinated butyl rubber, brominated butyl rubber, butadiene rubber, nitrile rubber, chloroprene rubber, ethylene propylene rubber and ethylene propylene diene rubber, specifically, butyl rubber and ethylene propylene diene rubber, or butadiene rubber and ethylene propylene diene rubber.

[0035] In the present invention, the weight of the synthetic rubber is preferably 85 to 90 parts, specifically 75 parts of butyl rubber and 10 parts of EPDM rubber, or 60 parts of butadiene rubber and 30 parts of EPDM rubber. The synthetic rubber is the main material for preparing the rubber pad. The present invention uses the synthetic rubber in a compounded manner to improve the mechanical properties of the rubber pad.

[0036] Based on 1 part by weight of the synthetic rubber, the weight of the silicon dioxide is preferably 15 to 30 parts. The silicon dioxide can improve the elongation at break of the material.

[0037] In the present invention, the carbon black preferably includes one or more of carbon black N110, N330, N550 and N990.

[0038] Based on 1 part by weight of the synthetic rubber, the weight of the carbon black is preferably 45 to 60 parts, specifically 45 parts, 50 parts or 60 parts. The carbon black can increase the hardness of the material.

[0039] In the present invention, the filler preferably includes one or more of calcium carbonate, talc, kaolin and clay.

[0040] Based on 1 part by weight of the synthetic rubber, the weight of the filler is preferably 25 to 35 parts. The filler can reduce the cost of materials.

[0041] In the present invention, the process oil preferably includes one or more of paraffin oil, naphthenic oil and aromatic oil.

[0042] Based on 1 part by weight of the synthetic rubber, the weight of the process oil is preferably 5 to 10 parts, specifically 5 parts, 8 parts or 10 parts. The process oil can improve the processing performance of the material and adjust the hardness of the material.

[0043] Based on 1 part by weight of the synthetic rubber, the weight of the stearic acid is preferably 1 to 3 parts. The stearic acid can improve the processing properties of the material.

[0044] Based on 1 part by weight of the synthetic rubber, the weight of the zinc oxide is preferably 4 to 8 parts. The zinc oxide is a vulcanizing agent.

[0045] In the present invention, the antioxidant preferably includes one or more of antioxidants RD, MB, AW, TPPD and 4010NA.

[0046] Based on 1 part by weight of the synthetic rubber, the weight of the antioxidant is preferably 1 to 1.5 parts. The antioxidant can prevent material aging.

[0047] In the present invention, the sulfur-containing phenolic resin preferably includes tert-octylphenolic vulcanized resin HY2045.

[0048] Based on 1 part by weight of the synthetic rubber, the weight of the sulfur-containing phenolic resin is preferably 5 to 10 parts. The sulfur-containing phenolic resin is a vulcanizing agent.

[0049] In one embodiment of the present invention, the rubber pad preferably includes the following raw materials in parts by weight: 75 parts of butyl rubber, 10 parts of EPDM rubber, 15 parts of silica, 25 parts of calcium carbonate, 60 parts of carbon black N330, 10 parts of paraffin oil, 1 part of stearic acid, 1 part of RD antioxidant, 4 parts of zinc oxide, and 5 parts of HY2045 phenolic resin; or 60 parts of butadiene rubber, 30 parts of EPDM rubber, 10 parts of silica, 35 parts of calcium carbonate, 50 parts of carbon black N330, 8 parts of paraffin oil, 1 part of stearic acid, 1 part of RD antioxidant, 4 parts of zinc oxide, and 5 parts of HY2045 phenolic resin; or 75 parts of nitrile rubber, 10 parts of EPDM rubber, 30 parts of silica, 25 parts of calcium carbonate, 45 parts of carbon black N330, 5 parts of paraffin oil, 1 part of stearic acid, 1 part of RD antioxidant, 4 parts of zinc oxide, and 10 parts of HY2045 phenolic resin.

[0050] The present invention also provides a method for preparing the rubber pad described in the above technical solution, comprising the following steps:

[0051] After the synthetic rubber is plasticized, it is mixed with silicon dioxide, carbon black, filler, process oil and stearic acid for a first banburying to obtain a mixture;

[0052] The mixed material, zinc oxide, antioxidant and sulfur-containing phenolic resin are mixed and kneaded for a second time to obtain a raw rubber compound;

[0053] The raw rubber material is extruded and calendered to obtain a rubber pad.

[0054] The invention plasticizes the synthetic rubber, and then mixes it with silicon dioxide, carbon black, filler, process oil and stearic acid for the first banburying to obtain a mixture.

[0055] In the present invention, the mastication is preferably performed at room temperature, and the number of thin passes of the mastication at room temperature is preferably 10 times.

[0056] In the present invention, the temperature of the first internal kneading is preferably 100 to 120° C., and the time is preferably 15 to 25 minutes. The first internal kneading is to preliminarily mix the raw materials without reaction activity.

[0057] In the present invention, the first internal kneading preferably further includes cooling to room temperature.

[0058] After obtaining the mixture, the present invention mixes the mixture, zinc oxide, an antioxidant and a sulfur-containing phenolic resin for a second mixing to obtain a raw rubber compound.

[0059] In the present invention, the temperature of the second banburying is preferably 50-60°C, and the time is preferably 3-5 minutes. The present invention adopts two banburyings, the first banburying is to preliminarily mix the non-reactive raw materials, and the second banburying is to mix the reactive raw materials, which can prevent premature vulcanization.

[0060] After obtaining the raw rubber compound, the present invention extrude and calender the raw rubber compound to obtain a rubber pad.

[0061] In the present invention, the raw rubber material is preferably left to stand before extrusion and calendering, and the standing time is preferably 8 to 12 hours. The function of the standing is to release the internal stress.

[0062] The present invention also provides a composite rubber pad, which comprises stacked rubber pads, and a temperature sensor and / or an electric heating device arranged between the rubber pad layers;

[0063] The rubber pad is the rubber pad described in the above technical solution or the rubber pad obtained by the above preparation method.

[0064] In the present invention, the temperature sensor is preferably a thermocouple, and the thermocouple preferably includes a K-type thermocouple, an E-type thermocouple, an S-type thermocouple or an N-type thermocouple. The present invention has no special requirements on the length of the thermocouple.

[0065] In the present invention, the electric heating device preferably includes a heating film, and the heating film preferably includes a polyimide heating film. The present invention has no special requirements on the shape and size of the heating film.

[0066] In the present invention, the thermocouple and the electric heating plate are preferably fixed on the surface of the rubber pad using epoxy resin prepreg.

[0067] In the present invention, the number of layers of the rubber pad is preferably 2. The weight of the composite rubber pad prepared by stacking the rubber pads is sufficient to provide the pressure required for curing the resin prepreg (1500g / m 2 ~4000g / m 2 ).

[0068] In the present invention, the composite rubber pad preferably further comprises an epoxy resin prepreg layer, the number of the epoxy resin prepreg layers is preferably 3, and the thickness of each epoxy resin prepreg layer is preferably 0.1 mm. The epoxy resin prepreg layer is preferably disposed between the rubber pad layers, which can enhance the shape retention capability of the prepared composite rubber pressure pad, so that the composite rubber pressure pad maintains the shape of the corresponding mold without collapse.

[0069] The present invention also provides a method for preparing the composite rubber pad described in the above technical solution, comprising the following steps:

[0070] After arranging the temperature sensor and / or the electric heating sheet on the surface of the rubber pad, the rubber pads are stacked to obtain a composite rubber pad.

[0071] In the present invention, after arranging the temperature sensor and / or the electric heating sheet, the method preferably further comprises: placing an epoxy resin prepreg layer.

[0072] The present invention also provides the use of the rubber pad or the composite rubber pad described in the above technical solution in the autoclave resin prepreg molding.

[0073] The present invention also provides a method for forming an autoclave resin prepreg, comprising the following steps:

[0074] vulcanizing the rubber pad or composite rubber pad described in the above technical solution in a mold to obtain a rubber pressure pad or a composite rubber pressure pad;

[0075] The resin prepreg is placed in the mold, and a release cloth, the rubber pressure pad or the composite rubber pressure pad, an isolation film, and a breathable felt are placed on the prepreg in sequence, and the prepreg is cured in an autoclave to obtain a molding material.

[0076] The present invention vulcanizes the rubber pad or the composite rubber pad described in the above technical solution in a mold to obtain a rubber pressure pad or a composite rubber pressure pad.

[0077] In the present invention, the vulcanization temperature is preferably 160-200°C, specifically 180°C, and the time is preferably 120-180 minutes, specifically 160 minutes. The vulcanization is preferably carried out in an autoclave, and the autoclave is equipped with an isolation film, a breathable felt, a vacuum bag film, and a sealing strip; the external pressure gauge pressure of the autoclave is preferably above 0.3MPa.

[0078] In the present invention, the Shore hardness of the rubber pressure pad is preferably 50-85, specifically 52, 63 or 80. The rubber pressure pad of the present invention is a soft material, which can form a perfect fit with the mold and has good conformability to the mold. When the R angle of the mold is small, the rubber pressure pad with a smaller hardness can extend to the inside of the R angle and play a role in pressure conduction.

[0079] In the present invention, the mold preferably includes a metal mold or a non-metal mold, and the present invention has no special requirements on the shape of the mold.

[0080] After obtaining the rubber pressure pad or the composite rubber pressure pad, the present invention places the resin prepreg in the mold, places the release cloth, the rubber pressure pad or the composite rubber pressure pad, the isolation film, and the breathable felt in sequence above the prepreg, and cures it in an autoclave to obtain a molding material.

[0081] In the present invention, a release cloth is preferably placed between the release cloth and the rubber pressure pad or the composite rubber pressure pad.

[0082] The present invention has no special requirements for the curing conditions, and the conditions commonly used by those skilled in the art may be adopted.

[0083] The present invention lays the rubber pressure pad on the release cloth of the autoclave, which can provide sufficient pressure for the resin prepreg during curing and molding; laying the composite rubber pressure pad can also perform real-time temperature monitoring and temperature compensation during the autoclave molding process. The rubber pressure pad and the composite rubber pressure pad are fitted to the mold, so that the obtained molding material has a high degree of curing and uniform quality.

[0084] In order to further illustrate the present invention, the rubber pad, composite rubber pad and its preparation method and application, and autoclave resin prepreg molding method provided by the present invention are described in detail below in combination with the drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0085] Example 1

[0086] A rubber pressure pad for autoclave composite material molding comprises the following raw materials in parts by weight: 75 parts of butyl rubber, 10 parts of EPDM rubber, 15 parts of silicon dioxide, 25 parts of calcium carbonate, 60 parts of carbon black N330, 10 parts of paraffin oil, 1 part of stearic acid, 1 part of RD antioxidant, 4 parts of zinc oxide and 5 parts of HY2045 phenolic resin.

[0087] Preparation method: First, the synthetic rubber is plasticized and thinned 10 times before unloading; the plasticized synthetic rubber, silica, carbon black, filler, operating oil, and stearic acid are added to the internal mixer for primary internal mixing at a temperature of 120°C for 15 minutes. After unloading, the temperature is lowered to room temperature, and the material, zinc oxide, antioxidant, and phenolic resin are added to the internal mixer for secondary internal mixing at a temperature of 60°C for 3 minutes. After the internal mixing of the raw rubber material is allowed to stand for 8 hours, it is put into the material port of the calendering extruder, extruded and rolled after cutting on both sides of the calendering, and the thickness of the unvulcanized rubber pad is 1.6mm and the width is 1.1m.

[0088] The unvulcanized rubber pad is vulcanized in an autoclave with corresponding molds, isolation membranes, breathable felt, vacuum bag films, sealing strips and other materials (the rubber pad is placed in a mold, an isolation membrane is added on top for isolation, and breathable felt is placed on top for air conduction, and then a vacuum system is constructed using vacuum bag films and sealing strips, the external pressure gauge pressure is 0.3 MPa, and it is placed in an autoclave for vulcanization), the vulcanization temperature is 160°C, and the vulcanization time is 120 minutes to obtain a rubber pressure pad.

[0089] Example 2

[0090] A rubber pressure pad for autoclave composite material molding comprises the following raw materials in parts by weight: 60 parts of butadiene rubber, 30 parts of EPDM rubber, 10 parts of silicon dioxide, 35 parts of calcium carbonate, 50 parts of carbon black N330, 8 parts of paraffin oil, 1 part of stearic acid, 1 part of RD antioxidant, 4 parts of zinc oxide and 5 parts of HY2045 phenolic resin.

[0091] Preparation method: First, the synthetic rubber is plasticized and thinned 10 times before unloading; the plasticized synthetic rubber, silica, carbon black, filler, operating oil, and stearic acid are added to the internal mixer for primary internal mixing, the internal mixing temperature is 120°C, and the internal mixing time is 15 minutes. After unloading, the temperature is cooled to room temperature, and the material, zinc oxide, antioxidant and phenolic resin are added to the internal mixer for secondary internal mixing, the internal mixing temperature is 50°C, and the internal mixing time is 5 minutes. After the internal mixing of the raw rubber material is left to stand for 8 hours, it is put into the material port of the calendering extruder, and the two sides of the extrusion calender are cut and then rolled up. The thickness of the unvulcanized rubber pad is 1.6mm and the width is 1.1m.

[0092] The unvulcanized rubber pad is vulcanized in an autoclave with corresponding molds, isolation membranes, breathable felt, vacuum bag films, sealing strips and other materials (the rubber pad is placed in a mold, an isolation membrane is added on top for isolation, a breathable felt is placed on top for air conduction, and then a vacuum system is constructed using vacuum bag films and sealing strips, and the pad is placed in an autoclave for vulcanization). The vulcanization temperature is 180°C and the vulcanization time is 120 minutes to obtain a rubber pressure pad.

[0093] Example 3

[0094] A rubber pressure pad for autoclave composite material molding comprises the following raw materials in parts by weight: 75 parts of nitrile rubber, 10 parts of EPDM rubber, 30 parts of silicon dioxide, 25 parts of calcium carbonate, 45 parts of carbon black N330, 5 parts of paraffin oil, 1 part of stearic acid, 1 part of RD antioxidant, 4 parts of zinc oxide, and 10 parts of HY2045 phenolic resin.

[0095] Preparation method: First, the synthetic rubber is plasticized and thinned 10 times before unloading; the plasticized synthetic rubber, silica, carbon black, filler, operating oil, and stearic acid are added to the internal mixer for primary internal mixing at a temperature of 100°C for 25 minutes. After unloading, the temperature is lowered to room temperature, and the material, zinc oxide, antioxidant, and phenolic resin are added to the internal mixer for secondary internal mixing at a temperature of 60°C for 3 minutes. After the internal mixing of the raw rubber material is allowed to stand for 8 hours, it is put into the material port of the calendering extruder, and the two sides of the extrusion calender are cut and then rolled up. The thickness of the unvulcanized rubber pad is 1.6 mm and the width is 1.1 m.

[0096] The unvulcanized rubber pad is vulcanized in an autoclave with corresponding molds, isolation films, breathable felt, vacuum bag films, sealing strips and other materials (the rubber pad is placed in a mold, an isolation film is added on top for isolation, breathable felt is placed on top for air conduction, and then a vacuum system is constructed using vacuum bag films and sealing strips, and the pad is placed in an autoclave for vulcanization). The vulcanization temperature is 160°C and the vulcanization time is 120 minutes to obtain a rubber pressure pad.

[0097] Example 4

[0098] A composite rubber pressure pad for real-time monitoring and compensation of the molding temperature of composite materials in an autoclave comprises the following raw materials in parts by weight: 60 parts of butadiene rubber, 30 parts of EPDM rubber, 10 parts of silicon dioxide, 35 parts of calcium carbonate, 50 parts of carbon black N330, 8 parts of paraffin oil, 1 part of stearic acid, 1 part of RD antioxidant, 4 parts of zinc oxide, and 5 parts of HY2045 phenolic resin.

[0099] Preparation method: First, the synthetic rubber is plasticized and thinned 10 times before unloading; the plasticized synthetic rubber, silica, carbon black, filler, operating oil, and stearic acid are added to the internal mixer for primary internal mixing, the internal mixing temperature is 120°C, and the internal mixing time is 15 minutes. After unloading, the temperature is cooled to room temperature, and the material, zinc oxide, antioxidant and phenolic resin are added to the internal mixer for secondary internal mixing, the internal mixing temperature is 50°C, and the internal mixing time is 5 minutes. After the internal mixing of the raw rubber material is left to stand for 8 hours, it is put into the material port of the calendering extruder, and the two sides of the extrusion calender are cut and then rolled up. The thickness of the unvulcanized rubber pad is 1.6mm and the width is 1.1m.

[0100] Spread the unvulcanized rubber pad flat on the operating table, arrange 2 K-type thermocouples and 2 polyamide heating films on the unvulcanized rubber pad, place 3 layers of epoxy resin prepreg (0.1 mm per layer), and then place a layer of unvulcanized rubber pad on the flat mold, and use the corresponding isolation film, breathable felt, vacuum bag film, sealing strip and other materials to vulcanize in the autoclave. The vulcanization temperature is 160°C and the vulcanization time is 120 minutes.

[0101] After cooling out of the tank, the circuit of the thermocouple and the polyamide heating film is inserted into the thermocouple temperature measuring instrument to obtain a composite rubber pressure pad used for real-time monitoring and compensation of the molding temperature of the composite material in the autoclave.

[0102] Table 1 shows the vulcanization and aging data of Example 1, Example 2 and Example 3, wherein the aging temperature is 180° C., the holding time is 3 hours, and the autoclave with an external pressure gauge pressure of 0.6 MPa is recorded as primary aging.

[0103] Table 1 Vulcanization and aging data of Example 1, Example 2 and Example 3

[0104]

[0105]

[0106] It can be seen from the data in Table 1 that the rubber pressure pad material prepared in the embodiment has little performance degradation after repeated use and can be reused.

[0107] Figure 1 The thermal weight loss curve of the rubber pressure pad of Example 2 shows that at 200°C, the rubber pressure pad of Example 2 has very good thermal stability and can maintain about 97% of its mass. The decomposition starting temperature is about 300°C, and the final residual mass is 32.7%.

[0108] The prepreg resin is placed on a mold brushed with a release agent, a release cloth is placed on top of the prepreg, and then an isolation film is added. Then, the rubber pressure pad vulcanized in Example 4 is placed on it, and then another layer of isolation film is added for isolation. A breathable felt is placed on it for air conduction, and then a vacuum system is constructed using a vacuum bag film and a sealing strip, and the prepreg is placed in an autoclave to cure. Figure 2 These are photos of the flat plate and special-shaped mold conformal sample preparation of the composite rubber pressure pad in Example 4. The composite rubber pressure pad can completely change with the shape of the mold, has good conformity to the mold during use, good pressure transmission, and high-quality composite material products.

[0109] Figure 3 This is a decomposition diagram of the implementation steps for arranging the thermocouple and the heating film in Example 4, step one: prepare an unvulcanized rubber pad, step two and step three: arrange the thermocouple and the heating film on the rubber pad and fix them with prepreg for temperature monitoring, step four: add three layers of prepreg, step five: cover with a layer of rubber pad to make a composite rubber pad that can be used for temperature monitoring and regulation.

[0110] Figure 4 The following is a comparison of samples made with and without the rubber pressure pad of Example 3. The left and middle are long strips of composite materials made with the rubber pressure pad of Example 3, while the right is a long strip of composite materials made without the rubber pressure pad of Example 3. From the red frame in the figure, it can be seen that due to insufficient pressure, there is obvious deformation on the surface of the workpiece. The workpiece is long, and bridges are easily formed in the middle, making pressure transmission difficult. The use of rubber pressure pads can avoid such problems.

[0111] Table 2 shows the curing degree test results (ASTM D7028-2007), which shows the glass transition temperatures at different points.

[0112] Table 2 Curing degree test results

[0113]

[0114]

[0115] From the curing degree data in Table 2, it can be seen that the glass transition temperature of the epoxy resin without the rubber pressure pad is lower, and the curing degree is lower than that of the product with the rubber pressure pad. The CV value of the curing degree without the rubber pressure pad is 3.78. However, the epoxy resin after the temperature compensation has a higher glass transition temperature and a higher curing degree, and the fluctuation of the value is also small, and the relative tolerance is only 1.88.

[0116] The rubber pad of the present invention can transmit pressure to the surface of the workpiece after vulcanization, and can provide sufficient pressure when the resin prepreg is cured, so that the layers of the resin prepreg are more compact, avoiding product defects caused by bridging of auxiliary materials during the curing process. The present invention improves the temperature consistency of the resin prepreg, and the molding quality of the obtained composite material is more uniform and stable. The rubber pressure pad of the present invention can be reused many times after molding, and has very good practicality.

[0117] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A rubber pad, characterized in that: The invention comprises the following raw materials in parts by weight: 70-100 parts of synthetic rubber, 10-50 parts of silicon dioxide, 30-80 parts of carbon black, 10-50 parts of filler, 5-15 parts of process oil, 0.5-5 parts of stearic acid, 1-10 parts of zinc oxide, 0.1-2 parts of antioxidant and 2-10 parts of sulfur-containing phenolic resin.

2. The rubber pad according to claim 1, characterized in that: The thickness of the rubber pad is 0.3-2.5 mm.

3. The rubber pad according to claim 1, characterized in that: The synthetic rubber includes one or more of butyl rubber, chlorinated butyl rubber, brominated butyl rubber, butadiene rubber, nitrile rubber, chloroprene rubber, ethylene propylene rubber and ethylene propylene diene monomer rubber.

4. The method for preparing a rubber pad according to any one of claims 1 to 3, characterized in that: The following steps are involved: After the synthetic rubber is plasticized, it is mixed with silicon dioxide, carbon black, filler, process oil and stearic acid for a first banburying to obtain a mixture; The mixed material, zinc oxide, antioxidant and sulfur-containing phenolic resin are mixed and kneaded for a second time to obtain a raw rubber compound; The raw rubber material is extruded and calendered to obtain a rubber pad.

5. The preparation method according to claim 4, characterized in that: The temperature of the first banburying is 100-120° C., and the time is 15-25 minutes.

6. The preparation method according to claim 4, characterized in that: The temperature of the second kneading is 50-60° C., and the time is 3-5 minutes.

7. A composite rubber pad, characterized in that: The composite rubber pad comprises stacked rubber pads, and a temperature sensor and / or an electric heating device arranged between the rubber pad layers; The rubber pad is the rubber pad according to any one of claims 1 to 3 or the rubber pad obtained by the preparation method according to any one of claims 4 to 6.

8. Use of the rubber pad according to any one of claims 1 to 3 or the composite rubber pad according to claim 7 in autoclave resin prepreg molding.

9. A method for forming an autoclave resin prepreg, characterized in that: The following steps are involved: vulcanizing the rubber pad according to any one of claims 1 to 3 or the composite rubber pad according to claim 7 in a mold to obtain a rubber pressure pad or a composite rubber pressure pad; The resin prepreg is placed in the mold, and a release cloth, the rubber pressure pad or the composite rubber pressure pad, an isolation film, and a breathable felt are placed on the prepreg in sequence, and the prepreg is cured in an autoclave to obtain a molding material.

10. The method according to claim 9, characterized in that The vulcanization temperature is 160-200° C. and the vulcanization time is 120-180 minutes.

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