A continuous process for the preparation of a polytrifluorochloroethylene-metal composite

Abstract

The application provides a kind of continuous preparation method of polytrifluorochloroethylene-metal composite, it is related to polymer-metal matrix composite field, the method comprises the following steps: S1, first, the metal surface combined with polytrifluorochloroethylene is treated using sand blasting process;S2, then, using the flat plate hot press with melting and cooling function, polytrifluorochloroethylene is heated and melted, and is filled in the cavity of the metal matrix after processing, then, after cooling and setting, polytrifluorochloroethylene-metal composite (valve) is prepared.Compared with the traditional fluoroplastic processing method, in the application, one equipment is used for heating and cooling to form polytrifluorochloroethylene, a new method of automatic hot-pressing forming polytrifluorochloroethylene-metal composite is developed, the method has the advantages of stable process and reliable quality, and has important application in polytrifluorochloroethylene valve sealing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polymer-metal matrix composites, and in particular to a continuous preparation method of a polytrifluorochloroethylene-metal composite. BACKGROUND

[0002] Polytrifluorochloroethylene (PCTFE) has very excellent low-temperature performance and can be used for a long time at -200 ℃, does not crack and does not creep in liquid nitrogen and liquid oxygen environments, and has important applications in the fields of electronics, electrical appliances, aerospace, etc. The movement flexibility of a new generation of carrier rocket filling valve / reducing valve is one of the keys to reliable operation of the valve, and therefore, a polytrifluorochloroethylene (F3) and metal composite structure is selected when designing valve products to achieve the sealing effect by using the low-temperature elasticity of fluoroplastic.

[0003] In the traditional process, one is to use cold pressing forming, that is, to use a physical method of metal flanging to effectively connect the non-metal; the other process is to first melt after heating, and then cool and shape in a cold press. However, the connection method of the former cannot meet the harsh working conditions of low temperature, ultra-high pressure and large flow of the new generation of products; the latter is the main method for preparing low-temperature valve clappers at present, and is also a common method for processing fluoroplastics. However, in this process, the mold needs to be transferred from a high-temperature state to a cold press, and the operation is manual, and the transfer process is difficult to control (such as time, pressure, etc.), which affects the product quality. In addition, the manual operation of the operator also has production safety hazards, and the process method of first melting and then cold pressing has the disadvantages of low qualification rate and poor reliability. Although various methods for improving the interface performance of PCTFE and metal have been proposed in subsequent research and development, such as spraying a dispersion liquid on the surface of the metal matrix or anodic oxidation treatment, the interface bonding force is improved to some extent. However, these complex processes will significantly increase the equipment investment, process cost and production time. For some occasions with lower performance requirements (such as low-temperature storage and transportation systems, etc.), the clapper valve prepared by the traditional process cannot meet the requirements, and the clapper valve prepared by the complex process has a low performance-price ratio. SUMMARY

[0004] In view of this, the purpose of the present application is to provide a continuous preparation method of a polytrifluorochloroethylene-metal composite.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] <First aspect>

[0007] The present application provides a continuous preparation method of a polytrifluorochloroethylene-metal composite, comprising the following steps:

[0008] S11, sandblasting treatment is performed on the cavity surface of the metal matrix;

[0009] S12, the polytrifluorochloroethylene particles are filled into the cavity of the metal matrix, and are placed in a temperature-controlled pressure device for continuous processing, and the specific processing process is as follows:

[0010] Melting stage: first, the pressure is increased to 1.0-2.0 MPa, then the temperature is increased to above the melting point and below the thermal decomposition temperature, until melting;

[0011] Cooling stage: continue to maintain the pressure, and cool to 150-180 ℃, then pressurize to 3.0-4.0 MPa, cool to room temperature, depressurize, and obtain a polytrifluorochloroethylene-metal composite.

[0012] As an embodiment, the melting stage is heated to 230-250 ℃.

[0013] As an embodiment, in the continuous processing, the heating rate and / or the cooling rate is 10-20 ℃ / min.

[0014] As an embodiment, the holding time in the melting stage is 15-90 min.

[0015] In some embodiments, the holding time in the melting stage is 45-90 min.

[0016] In some embodiments, the holding time in the melting stage is 45-60 min.

[0017] As an embodiment, in the cooling stage, the cooling rate is 10-15 ℃ / min, and after cooling to 150-180 ℃, the pressurization amplitude is 1-2 MPa.

[0018] As an embodiment, the temperature-controlled pressure device is a device capable of continuous temperature control and pressure control.

[0019] In some embodiments, the temperature-controlled pressure device is a flat curing press.

[0020] As an embodiment, the abrasive used in the sandblasting treatment is one or more of brown corundum, white corundum, and single-crystal corundum.

[0021] In some embodiments, the abrasive particle is brown corundum.

[0022] As an embodiment, the abrasive particle size is 20-100 mesh, the sandblasting pressure is 0.5-1.5 MPa, the sandblasting distance is 20-50 cm, and the sandblasting time is 5-15 s.

[0023] In some embodiments, the abrasive particle size is 20-50 mesh, the sandblasting pressure is 0.5-1 MPa, the sandblasting distance is 20-30 cm, and the sandblasting time is 5-10 s.

[0024] As an embodiment, the size of the polytrifluorochloroethylene particles is 20-100 mesh.

[0025] In some embodiments, the polychlorotrifluoroethylene particles have a size of 50 mesh.

[0026] As an embodiment, the metal substrate is one of aluminum alloy, stainless steel and titanium alloy.

[0027] <Second Aspect>

[0028] The present invention provides a polychlorotrifluoroethylene-metal composite body, which is prepared by the above method.

[0029] As an embodiment, in the composite, polychlorotrifluoroethylene and the metal substrate are directly bonded.

[0030] As an embodiment, the pull-out strength of the composite is 10 to 20 MPa, and the cryogenic sealing qualification rate is 70 to 90%.

[0031] As an embodiment, the pull-out strength of the composite is 12 to 18 MPa, and the cryogenic sealing qualification rate is 73 to 85%.

[0032] As an embodiment, the pull-out strength of the composite is 12 to 17.8 MPa, and the cryogenic sealing qualification rate is 73 to 85%.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1) The present invention improves the continuous temperature-controlled pressure treatment process, completing the melting and cooling processes in one device, accurately controlling parameters such as temperature and pressure in stages, and promoting the interfacial bonding between polytrifluorochloroethylene and the metal substrate through mechanical meshing, effectively reducing interfacial defects and improving bonding strength;

[0035] 2) During the melting stage, a pressure-melting mode is used. Applying a low initial pressure (1-2 MPa) during the material melting process ensures that the polytrifluorochloroethylene is fully melted and the melt and the metal matrix are fully infiltrated. The pressure suppresses the formation of bubbles inside the melt and prevents the material from overflowing the cavity due to the viscous flow volume expansion when the pressure is high during melting.

[0036] 3) In the cooling stage, the temperature is first lowered at a lower pressure to allow polytrifluorochloroethylene to crystallize, and then the pressure is increased and the temperature is further lowered to room temperature. The pressure is used to supplement the cooling shrinkage, reduce the interfacial gap and stress, and improve the bonding tightness;

[0037] 4) A seamless continuous control process is adopted in the melting and cooling stages, without sudden changes in pressure and temperature, eliminating the internal stress of the material caused by sudden changes, improving the uniformity of product performance and enhancing bonding strength;

[0038] 5) Compared with the complex treatment methods such as dispersion or anodizing used in the prior art, the present invention only treats the metal surface through sandblasting, eliminating the consumption of raw materials for chemical pretreatment and environmental treatment costs. At the same time, the continuous treatment reduces process switching time, improves unit time production capacity, and reduces overall production costs;

[0039] 6) The polychlorotrifluoroethylene-metal composite prepared by this invention is slightly inferior to composites prepared by complex processing methods in a few test indicators. However, it can meet the needs of many scenarios that do not require extreme performance but are sensitive to cost and production efficiency, such as low-cost commercial rockets. This provides a more economical technical path for the large-scale application of polychlorotrifluoroethylene-metal composites. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0041] Figure 1 A longitudinal cross-sectional view of a metal substrate used in the present invention;

[0042] Figure 2 A longitudinal cross-sectional view of a mold assembly for preparing a polytrifluorochloroethylene-metal composite according to the present invention;

[0043] Figure 3 For the present invention Figure 2 Corresponding explosion diagram;

[0044] Figure 4 The present invention adopts Figure 2 Schematic diagram of the structure of the polytrifluorochloroethylene-metal composite prepared by the mold shown;

[0045] Figure 5 The present invention adopts Figure 2 A longitudinal cross-sectional view of a polytrifluorochloroethylene-metal composite prepared by the mold shown;

[0046] Figure 6 A longitudinal cross-sectional view of a mold assembly for preparing a polytrifluorochloroethylene-metal composite according to the present invention;

[0047] Figure 7 The present invention adopts Figure 6 Schematic diagram of the structure of the polytrifluorochloroethylene-metal composite prepared by the mold shown;

[0048] Figure 8 A polytrifluorochloroethylene-metal composite prepared by the mold shown in the present application Figure 6 A longitudinal sectional view of a polytrifluorochloroethylene-metal composite prepared by the mold shown in the present application

[0049] Figure 9 A schematic diagram of a tensile strength test for a polytrifluorochloroethylene-metal composite prepared in the present application

[0050] Figure 10 A photo of a mold after the mold is removed from the sample preparation in the fungus-shaped tooling for the tensile strength test in the present application

[0051] In the figure, 1, metal matrix; 2, outer mold; 3, upper mold; 4, circular cavity; 41, upper cavity; 42, lower cavity; 5, polytrifluorochloroethylene sealing ring; 6, inner mold. DETAILED DESCRIPTION

[0052] The present application will be described in detail below with reference to examples. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present application. These are within the scope of protection of the present application.

[0053] The present embodiment provides a continuous preparation method of a polytrifluorochloroethylene-metal composite, the steps are as follows:

[0054] S11, sandblasting treatment is performed on the cavity surface of the metal matrix;

[0055] S12, polytrifluorochloroethylene particles are filled into the cavity of the metal matrix, and the mold is assembled and placed in a temperature-controlled pressure device for continuous processing, and the specific processing process is as follows:

[0056] Melting stage: first, increase the pressure to the first pressure (1.0-2.0 MPa), increase the temperature to the first temperature (above the melting point and below the thermal decomposition temperature) at the first rate (10-20 ℃ / min), and then maintain the first time (45-90 min);

[0057] Cooling stage: continue to maintain the pressure, decrease the temperature to the second temperature (150-180℃) at the second rate (10-20 ℃ / min), then increase the pressure to the second pressure (3.0-4.0 MPa), decrease the temperature to room temperature at the third rate (10-20 ℃ / min), and then release the pressure to obtain a polytrifluorochloroethylene-metal composite.

[0058] Further, the abrasive used for sandblasting treatment is brown corundum, the abrasive particle size is 20-100 mesh, the sandblasting pressure is 0.5-1 MPa, the sandblasting distance is 15-25 cm, and the sandblasting time is 3-10 s.

[0059] Further, the particle size of the polytrifluorochloroethylene is 20-100 mesh. If the particle size is too large, the volume is large, the shrinkage ratio is large after melting and pressing, which is not conducive to forming; if the particle size is too small, the heating is unstable and is easy to oxidize to form black spots.

[0060] Further, in the melting stage, the temperature is raised to 230-250 DEG C.

[0061] It should be noted that in the present application, the temperature control pressure equipment is selected to be a flat curing machine, which has the functions of heating and programmed cooling.

[0062] As shown in Figure 1 , the structure of the metal base 1 used is as follows:

[0063] The metal base 1 is a one-piece structure, which is divided into upper and lower parts from the structure. The lower part is a cylinder with a circular ring cavity 4 opened on the upper surface. The circular ring cavity 4 is divided into upper and lower parts. The upper cavity 41 is a non-variable diameter annular cavity, and the lower cavity 42 is a tapered cavity with a small upper part and a large lower part. The angle of the conical surface (the angle between the generatrix and the bottom surface) is 75-85 DEG (75 DEG in the present application). The upper part is a protruding cylinder extending radially upward from the inner diameter of the upper cavity 41.

[0064] As shown in Figure 2 and Figure 3 In the preparation of the polytrifluorochloroethylene-metal composite, the matched mold includes an outer mold 2 and an upper mold 3.

[0065] The outer mold 2 is a circular ring structure, and its inner diameter is consistent with the outer diameter of the upper cavity 41.

[0066] The upper mold 3 is a circular ring structure, which can also be a lower open cylindrical structure. The inner diameter of the upper mold 3 is consistent with the diameter of the protruding cylinder, and the outer diameter matches the inner diameter of the outer mold 2.

[0067] When assembling, the polytrifluorochloroethylene is placed in the circular ring cavity 4 (i.e. the cavity), and the upper mold 3 and the outer mold 2 are sleeved from top to bottom, and then placed in the temperature control pressure equipment. Pressure is applied above the upper mold 3 to press the polytrifluorochloroethylene downward.

[0068] It should be noted that the outer mold 2 does not bear the external applied pressure, and its height after assembly is not higher than the height of the outer mold 2; the height of the protruding cylinder also does not bear the external applied pressure, and its height is not higher than the height of the outer mold 2 after assembly.

[0069] The prepared polytrifluorochloroethylene-metal composite is as shown in Figure 4 and Figure 5 In the figure, the polytrifluorochloroethylene sealing ring 5 is embedded in the circular ring cavity 4 of the metal base 1.

[0070] It should be noted that the binding force between the polytrifluorochloroethylene and the metal is not strong, and after the preparation is completed, the outer mold 2 and the upper mold 3 can be disassembled to obtain a polytrifluorochloroethylene-metal composite.

[0071] In actual implementation, the surfaces of the outer mold 2 and the upper mold 3 that contact the polytrifluorochloroethylene can be selected from metals with small surface roughness (such as Ra=0.4 μm or less), or can be selected from surfaces plated with a hard chromium layer as the contact surface, and the mold can be separated relatively easily.

[0072] The metal matrix can be changed according to actual conditions, and the corresponding mold is also changed, such as:

[0073] When the diameter of the protruding cylinder on the upper part of the metal matrix 1 is smaller than the inner diameter of the upper cavity 41, as shown in FIG. 1B, the mold further includes an inner mold 6, the inner diameter of which is consistent with the outer diameter of the protruding cylinder, and the outer diameter of which is matched with the inner diameter of the upper mold 3. Figure 6

[0074] In use, an additional step of sleeving the inner mold 6 outside the protruding cylinder is added.

[0075] The polytrifluorochloroethylene-metal composite prepared using the mold is as shown in FIGS. 1C and 1D. Figure 7 Figure 8

[0076] The above method is specifically introduced through several examples (see Table 1) and comparative examples.

[0077] In the examples and comparative examples, the raw material polytrifluorochloroethylene particles are 50 mesh.

[0078] Table 1

[0079]

[0080] Comparative Example 1

[0081] A non-continuous preparation method of a polytrifluorochloroethylene-metal composite, the steps are as follows:

[0082] S21, same as step S11 in the above continuous preparation method, the parameters are the same as Example 1;

[0083] S22, fill the polytrifluorochloroethylene into the cavity of the metal matrix, and complete the melting and cooling processes through two devices of a hot press and a cold press, specifically:

[0084] ​​​First melt in the hot press, the parameters are: first increase to 1.0 MPa, increase to 230 DEG C at the rate of 20 DEG C / min, keep 60 min; then quickly transfer to the cold press, apply 1.0 MPa pressure, utilize ambient temperature to reduce temperature, through infrared thermometer monitor temperature reduce to 150 DEG C, increase to 3.0 MPa, continue to reduce temperature to room temperature, obtain the non-continuous preparation of polytrifluorochloroethylene-metal composite.

[0085] Comparative example 2

[0086] A non-continuous preparation method of polytrifluorochloroethylene-metal composite, the steps are as follows:

[0087] S21, same as step S11 in the above continuous preparation method, parameters are same as example 1;

[0088] S22, fill polytrifluorochloroethylene into the cavity of metal matrix, complete melting and cooling process through two equipments of hot press and cold press, specifically:

[0089] First melt in the hot press, the parameters are: first increase to 1.0 MPa, increase to 230 DEG C at the rate of 20 DEG C / min, keep 60 min; then quickly transfer to the cold press, apply 1.0 MPa pressure, utilize ambient temperature to reduce temperature to room temperature, obtain the non-continuous preparation of polytrifluorochloroethylene-metal composite.

[0090] Comparative example 3

[0091] A non-continuous preparation method of polytrifluorochloroethylene-metal composite, the steps are as follows:

[0092] S21, same as step S11 in the above continuous preparation method, parameters are same as example 3;

[0093] S22, fill polytrifluorochloroethylene into the cavity of metal matrix, complete melting and cooling process through two equipments of hot press and cold press, specifically:

[0094] First melt in the hot press, the parameters are: first increase to 2.0 MPa, increase to 230 DEG C at the rate of 20 DEG C / min, keep 60 min; then quickly transfer to the cold press, apply 2.0 MPa pressure, utilize ambient temperature to reduce temperature, through infrared thermometer monitor temperature reduce to 150 DEG C, increase to 3.0 MPa, continue to reduce temperature to room temperature, obtain the non-continuous preparation of polytrifluorochloroethylene-metal composite.

[0095] Comparative example 4

[0096] A non-continuous preparation method of polytrifluorochloroethylene-metal composite, the steps are as follows:

[0097] S21, same as step S11 in the above continuous preparation method, parameters are same as example 3;

[0098] S22, fill the polytrifluorochloroethylene into the cavity of the metal matrix, complete the melting and cooling process through two devices of hot press and cold press, specifically:

[0099] First melt in the hot press, parameters are as follows: first increase the pressure to 2.0 MPa, increase the temperature to 230℃ at a rate of 20℃ / min, keep for 60 min; then quickly transfer to the cold press, apply a pressure of 2.0 MPa, reduce the temperature to room temperature by using the ambient temperature, to obtain the non-continuous preparation of polytrifluorochloroethylene-metal composite.

[0100] Comparative example 5

[0101] A non-continuous preparation method of polytrifluorochloroethylene-metal composite, the steps are as follows:

[0102] S21, same as step S11 in the above continuous preparation method, parameters are same as example 4;

[0103] S22, fill the polytrifluorochloroethylene into the cavity of the metal matrix, complete the melting and cooling process through two devices of hot press and cold press, specifically:

[0104] First melt in the hot press, parameters are as follows: first increase the pressure to 1.0 MPa, increase the temperature to 230℃ at a rate of 20℃ / min, keep for 60 min; then quickly transfer to the cold press, apply a pressure of 1.0 MPa, reduce the temperature by using the ambient temperature, monitor the temperature by using the infrared temperature detector, when the temperature reduces to 150℃, increase the pressure to 4.0 MPa, continue to reduce the temperature to room temperature, to obtain the non-continuous preparation of polytrifluorochloroethylene-metal composite.

[0105] Comparative example 6

[0106] A non-continuous preparation method of polytrifluorochloroethylene-metal composite, the steps are as follows:

[0107] S21, same as step S11 in the above continuous preparation method, parameters are same as example 4;

[0108] S22, fill the polytrifluorochloroethylene into the cavity of the metal matrix, complete the melting and cooling process through two devices of hot press and cold press, specifically:

[0109] The melt was first carried out in a hot press with the following parameters: first, the pressure was increased to 1.0 MPa, the temperature was increased to 230 °C at a rate of 20 °C / min, and maintained for 60 min; then, the melt was quickly transferred to a cold press, a pressure of 1.0 MPa was applied, and the temperature was cooled to room temperature using ambient temperature to obtain a discontinuously prepared polytrifluorochloroethylene-metal composite.

[0110] Comparative Example 7

[0111] A discontinuous preparation method of a polytrifluorochloroethylene-metal composite comprises the following steps:

[0112] S21, following step S11 in the above continuous preparation method, with the same parameters as in Example 7;

[0113] S22. Fill polytrifluorochloroethylene into the mold cavity of the metal matrix, and complete the melting and cooling processes through two devices, a hot press and a cold press. Specifically, first melt it in the hot press with the following parameters: first increase the pressure to 1.0 MPa, increase the temperature to 230°C at a rate of 20°C / min, and maintain for 90 minutes; then quickly transfer it to the cold press, apply a pressure of 1.0 MPa, cool it down using the ambient temperature, monitor the temperature with an infrared thermometer until it drops to 150°C, then increase the pressure to 4.0 MPa, and continue to cool it to room temperature to obtain a discontinuously prepared polytrifluorochloroethylene-metal composite.

[0114] Comparative Example 8

[0115] A discontinuous preparation method of a polytrifluorochloroethylene-metal composite comprises the following steps:

[0116] S21, following step S11 in the above continuous preparation method, with the same parameters as in Example 7;

[0117] S22, filling polytrifluorochloroethylene into the cavity of the metal matrix, and completing the melting and cooling process by two devices, a hot press and a cold press, specifically:

[0118] The melt was first carried out in a hot press with the following parameters: first increasing the pressure to 1.0 MPa, heating to 230 °C at a rate of 20 °C / min, and maintaining for 90 min; then the melt was quickly transferred to a cold press, where a pressure of 1.0 MPa was applied and the melt was cooled to room temperature using ambient temperature to obtain a discontinuously prepared polytrifluorochloroethylene-metal composite.

[0119] Comparative Example 9

[0120] A continuous preparation method of a polytrifluorochloroethylene-metal composite comprises the following steps:

[0121] S21, same as step S11 in the above continuous preparation method, with the same parameters as in Example 1;

[0122] S22, as in step S12 of the above-mentioned continuous preparation method, the parameters of the melting stage are the same as those of Example 1, but the step-by-step pressure reduction treatment is not used in the cooling stage, specifically:

[0123] Cooling stage: Maintain a pressure of 1.0 MPa, cool to room temperature at a rate of 10 ℃ / min, and then release the pressure.

[0124] Comparative Example 10

[0125] A continuous preparation method of a polytrifluorochloroethylene-metal composite comprises the following steps:

[0126] S21, same as step S11 in the above continuous preparation method, with the same parameters as in Example 1;

[0127] S22, as in step S12 of the above continuous preparation method, the parameters of the melting stage are the same as those of Example 1, but the cooling stage is adjusted to:

[0128] Cooling stage: maintain the pressure of 1.0 MPa, cool to 200 °C at a rate of 10 °C / min, then increase the pressure to 3.0 MPa, continue to cool to room temperature at a rate of 10 °C / min, and release the pressure.

[0129] During the cooling phase, slight flashing occurred.

[0130] Comparative Example 11

[0131] A continuous preparation method of a polytrifluorochloroethylene-metal composite comprises the following steps:

[0132] S21, same as step S11 in the above continuous preparation method, with the same parameters as in Example 1;

[0133] S22, as in step S12 of the above-mentioned continuous preparation method, the parameters of the melting stage are the same as those of Example 1, but the step-by-step pressure reduction treatment is not used in the cooling stage, specifically:

[0134] Cooling stage: Increase the pressure to 3.0 MPa, cool to room temperature at a rate of 10 ℃ / min, and then release the pressure.

[0135] During the cooling stage, the overflow is more serious.

[0136] Comparative Example 12

[0137] A continuous preparation method of a polytrifluorochloroethylene-metal composite comprises the following steps:

[0138] S21, same as step S11 in the above continuous preparation method, with the same parameters as in Example 1;

[0139] S22, same as step S12 in the above continuous preparation method, the parameters of the cooling stage are the same as in Example 1, but the parameters of the melting stage are changed, specifically:

[0140] Melting stage: first increase to 1.0, increase to 220°C at a rate of 20°C / min, and maintain for 60 min.

[0141] Comparative Example 13

[0142] A continuous preparation method of a polytrifluorochloroethylene-metal composite, the steps are as follows:

[0143] S21, same as step S11 in the above continuous preparation method, the parameters are the same as in Example 1;

[0144] S22, same as step S12 in the above continuous preparation method, the parameters of the cooling stage are the same as in Example 1, but the parameters of the melting stage are changed, specifically:

[0145] Melting stage: first increase to 1.0, increase to 230°C at a rate of 20°C / min, and maintain for 15 min.

[0146] Comparative Example 14

[0147] A continuous preparation method of a polytrifluorochloroethylene-metal composite, the steps are as follows:

[0148] S21, same as step S11 in the above continuous preparation method, the parameters are the same as in Example 1;

[0149] S22, same as step S12 in the above continuous preparation method, the parameters of the cooling stage are the same as in Example 1, but the parameters of the melting stage are changed, specifically:

[0150] Melting stage: first increase to 1.0, increase to 260°C at a rate of 20°C / min, and maintain for 60 min.

[0151] Performance testing

[0152] (1) Tensile strength test

[0153] The tensile strength test was performed using a self-made bacterial-shaped tooling as shown in Figure 10 , wherein the tooling was placed in a universal testing machine for testing at a stretching rate of 5 mm / min, and the maximum tensile force value when the metal substrate and fluoroplastic were debonded was recorded. Figure 9

[0154] It should be noted that the bacterial-shaped tooling is used for tensile strength testing in the present application, and the bacterial-shaped tooling includes two metal parts symmetrically arranged and a middle mold, wherein,

[0155] ​The metal parts are cylindrical structures with a pull-out protrusion on one side. The diameters of the two cylindrical structures are the same and they are symmetrically arranged when in use.

[0156] The middle die is a circular ring sleeve, and the inner diameter is consistent with the cylindrical structure of the metal part.

[0157] When in use, the middle mold is first placed on the cylindrical structure of a metal component, and polytrifluorochloroethylene is filled into the cavity formed by the two. Then another metal component is assembled to form a symmetrical arrangement of two metal components. The middle mold is placed on the outside of the cylindrical structure of the two metal components, and the cavity formed between the three is filled with polytrifluorochloroethylene.

[0158] It should be noted that the material of the two metal components is consistent with the material of the metal substrate in the above-mentioned embodiments or comparative examples. Corresponding sandblasting treatment is performed, and a pressing test corresponding to the embodiments or comparative examples is performed to prepare a bonding surface consistent with the corresponding sample, so as to analyze the pull-out strength of the prepared polytrifluorochloroethylene-metal composite valve disc.

[0159] After pressing, the fungus-shaped tooling sample photo is taken after the middle mold is removed. Figure 10 shown.

[0160] In the test of the present invention, the diameter of the contact surface of the metal and non-metal in the fungus-shaped tooling used is 20 mm; the pull-out strength = maximum tensile force / cross-sectional area, the cross-sectional area is π × 100 mm 2 .

[0161] It should be noted that, in order to facilitate the disassembly of the middle mold, the inner surface thereof can refer to the roughness setting or coating setting of the outer mold 2 and the upper mold 3 in the above embodiments.

[0162] (2) Sealing test in cryogenic environment

[0163] Install the cryogenic valve disc on the gas-penetrating fixture, fill it with 1MPa of gas, immerse the valve disc in a liquid nitrogen cryogenic environment for at least 4 hours to cool it down, and then transfer it to anhydrous ethanol (or pour anhydrous ethanol into the groove of the gas-penetrating fixture). Observe whether there are continuous bubbles on the sealing surface. If there are no bubbles, it is qualified.

[0164] The qualified rate of cryogenic sealing performance = the number of qualified samples / the number of tested samples × 100%, where the number of tested samples for each embodiment or comparative example is 100.

[0165] The test results are listed in Table 2.

[0166] Table 2

[0167]

[0168] As can be seen from Table 2, the performance of the direct bonding of polytrifluorochloroethylene and a metal substrate is significantly improved by the improvement of the production process.

[0169] The above describes specific embodiments of the present application. It should be understood that the present application is not limited to the specific embodiments described above, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which do not affect the essence of the present application.

Claims

1. A method for continuously preparing a polytrifluorochloroethylene-metal composite, characterized in that: The following steps are involved: S11, performing sandblasting on the cavity surface of the metal substrate; S12, filling the polytrifluorochloroethylene particles into the cavity of the metal matrix and placing it in a temperature-controlled pressure device for continuous treatment. The specific treatment process is as follows: Melting stage: first increase the pressure to 1.0~2.0 MPa, then increase the temperature to above the melting point and below the thermal decomposition temperature until it is completely melted; Cooling stage: continue to maintain the pressure, cool to 150-180 °C, then pressurize to 3.0-4.0 MPa, cool to room temperature, release the pressure, and obtain the polytrifluoroethylene-metal composite; In the continuous treatment, the heating rate and / or cooling rate is 10-20°C / min.

2. The method according to claim 1, characterized in that The abrasive used in the sandblasting process is one or more of brown corundum, white corundum and single crystal corundum.

3. The method according to claim 2, characterized in that The abrasive particle size is 20-100 mesh, the sandblasting pressure is 0.3-1 MPa, the sandblasting distance is 20-50 cm, and the sandblasting time is 3-10 s.

4. The method according to claim 1, wherein The size of the polytrifluorochloroethylene particles is 20-100 meshes.

5. The method according to claim 1, wherein The metal matrix is ​​one of aluminum alloy, stainless steel, and titanium alloy.

6. The method according to claim 1, characterized in that The temperature in the melting stage is raised to 230-250°C.

7. The method according to claim 1, characterized in that During the melting stage, the holding time is 15 to 90 minutes.

8. The method according to claim 1, characterized in that The temperature-control and pressure-control device is a device capable of continuously performing temperature control and pressure control.

9. A polychlorotrifluoroethylene-metal composite prepared by the method according to any one of claims 1 to 8, characterized in that: In the composite, polytrifluorochloroethylene and the metal matrix are directly bonded, the tensile strength of the composite is 10-20 MPa, and the cryogenic sealing qualification rate is 70-90%.

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