Polytetrafluoroethylene resin material as well as preparation method and application thereof
By adding perfluoroalkoxy resin and fluorinated ethylene propylene copolymer to polytetrafluoroethylene resin material and optimizing the preparation process, the problems of high hardness and poor flexibility of PTFE gaskets were solved, achieving better sealing and transparency, and ensuring the reliability of plate heat exchangers.
Patent Information
- Application Number
- CN202511264900.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-05
- Publication Date
- 2025-11-18
AI Technical Summary
Existing polytetrafluoroethylene (PTFE) gaskets have high hardness and poor flexibility, making it difficult to detect internal air bubbles, which leads to leaks in plate heat exchangers.
By adding perfluoroalkoxy resin and fluorinated ethylene propylene copolymer as organic additives and optimizing the preparation process of polytetrafluoroethylene resin materials, its flexibility and transparency are improved, ensuring that bubbles can be detected in a timely manner.
The prepared E+PTFE coated gasket is softer, has improved sealing and pressure resistance, and enhanced transparency, enabling timely detection of internal air bubbles, ensuring product quality, and preventing leakage.
Smart Images
Figure CN120966168A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of PTFE coating materials, and particularly relates to a polytetrafluoroethylene resin material and a preparation method and application thereof. BACKGROUND
[0002] The plate heat exchanger is a high-efficiency energy-saving heat exchange device, and is widely used in production and life. It is usually formed by a plurality of thin plates punched with corrugations arranged at a certain interval, sealed by gaskets around, and overlapped and compressed by frames and compression screws. The four corner holes of the plate and the gasket can form distribution pipes and collection pipes of fluid, and reasonably separate the cold and hot fluids to flow in the flow channels on both sides of each plate respectively, and perform heat exchange through the plates.
[0003] The sealing gasket is an important component of the plate heat exchanger, and has an important influence on the service life of the plate heat exchanger. The sealing gasket not only seals the medium to prevent it from leaking to the external environment, but also prevents the mutual mixing of heat exchange media. If the sealing gasket has a problem, the plate heat exchanger may not operate normally.
[0004] At present, the sealing gasket used in the plate heat exchanger is a polytetrafluoroethylene (PTFE) and ethylene-propylene-diene rubber (EPDM) composite gasket (PTFE / EPDM composite gasket, E+PTFE coated gasket). The E+PTFE coated gasket has very good chemical resistance.
[0005] However, the E+PTFE coated gasket currently uses PTFE which is white, opaque and has high hardness. The produced E+PTFE coated gasket has high hardness on the outside, which is not conducive to overall pressure bearing and use. If the internal gas cannot be discharged during the vulcanization production process, the gas will accumulate between the EPDM base material and the PTFE film to form a bubble waste product. At the same time, since the PTFE is white, the bubble is generally difficult to find inside the PTFE film. During use of the E+PTFE coated gasket, the bubble is a weak link of the E+PTFE coated gasket, and the plate heat exchanger is prone to leakage. SUMMARY
[0006] The purpose of the present application is to provide a polytetrafluoroethylene resin material and a preparation method and application thereof. The polytetrafluoroethylene resin material provided by the present application has better flexibility and transparent properties. The produced E+PTFE coated gasket is softer, has improved sealing performance and pressure bearing capacity, and the PTFE film material is transparent. Even if bubbles are generated inside, they can be found in time, ensuring the quality of the E+PTFE coated gasket product and effectively avoiding leakage.
[0007] In order to achieve the above purpose, the present application provides the following technical scheme:
[0008] The application provides a polytetrafluoroethylene resin material, which comprises the following raw materials in mass fractions: 90-100 parts of polytetrafluoroethylene, 1-10 parts of an organic additive and 15-25 parts of a lubricant; the organic additive comprises perfluoroalkoxy resin and / or fluorinated ethylene propylene copolymer.
[0009] Preferably, when the additive comprises perfluoroalkoxy resin and fluorinated ethylene propylene copolymer, the mass fraction of the perfluoroalkoxy resin is 0.5-3 parts, and the mass fraction of the fluorinated ethylene propylene copolymer is 0.5-9 parts.
[0010] Preferably, the perfluoroalkoxy resin is polymerized from tetrafluoroethylene and perfluoroalkoxy vinyl ether; and the fluorinated ethylene propylene copolymer is copolymerized from tetrafluoroethylene and hexafluoropropylene.
[0011] Preferably, the lubricant is petroleum ether.
[0012] The application provides a preparation method of the polytetrafluoroethylene resin material.
[0013] The raw materials of the polytetrafluoroethylene resin material are mixed to obtain a mixture;
[0014] The mixture is placed in a mold for molding to obtain a green body;
[0015] The green body is sintered to obtain the polytetrafluoroethylene resin material.
[0016] Preferably, the mixing is carried out under stirring, and the stirring speed is 15-30 r / min, and the stirring time is 10-20 min.
[0017] Preferably, the molding comprises sequentially performing first molding, second molding and third molding, the pressure of the first molding is 10-20 MPa, the second molding is performed after the first molding is exhausted, and the pressure of the second molding is 25-35 MPa; the pressure of the third molding is 30-40 MPa, and the pressure maintaining time is 5-10 min.
[0018] Preferably, the sintering comprises: first temperature maintaining by heating from room temperature to a first temperature at a first heating rate, then second temperature maintaining by heating from the first temperature to a second temperature at a second heating rate, and then cooling from the second temperature to room temperature; the first heating rate is 10-20 ℃ / h, the first temperature is 200-250 ℃, the first temperature maintaining time is 1-2 h, the second heating rate is 10-15 ℃ / h, the second temperature is 350-380 ℃, the second temperature maintaining time is 30-240 min, and the cooling rate is 10-30 ℃ / h.
[0019] The application provides application of the polytetrafluoroethylene resin material in a polytetrafluoroethylene coated sealing gasket.
[0020] The application provides a sealing gasket coated gasket, which comprises a EPDM base material and a polytetrafluoroethylene film coated on the surface of the EPDM base material, wherein the polytetrafluoroethylene film is the polytetrafluoroethylene resin material in the technical solution or the polytetrafluoroethylene resin material prepared by the preparation method.
[0021] The application provides a polytetrafluoroethylene resin material, which comprises the following preparation raw materials in mass fraction: 90-100 parts of polytetrafluoroethylene, 1-10 parts of organic additive and 15-25 parts of lubricant; the organic additive comprises perfluoroalkoxy resin and / or fluorinated ethylene propylene copolymer.
[0022] The application provides a preparation method of the polytetrafluoroethylene resin material, which comprises the following steps: mixing preparation raw materials of the polytetrafluoroethylene resin material to obtain a mixture; placing the mixture in a mold for die pressing to obtain a blank; and sintering the blank to obtain the polytetrafluoroethylene resin material. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 The large circle in the figure is the PTFE film prepared in Example 1, Figure 1 The small circle in the figure is the PTFE film prepared in Comparative Example 1. Figure 1 The small circle in the figure is the PTFE film prepared in Comparative Example 1. DETAILED DESCRIPTION
[0024] The application provides a polytetrafluoroethylene resin material, which comprises the following preparation raw materials in mass fraction: 90-100 parts of polytetrafluoroethylene, 1-10 parts of organic additive and 15-25 parts of lubricant; the organic additive comprises perfluoroalkoxy resin (PFA) and / or fluorinated ethylene propylene copolymer (FEP).
[0025] In the present application, all the preparation raw materials / components are commercially available products well known to those skilled in the art, unless otherwise specified.
[0026] The preparation raw materials of the polytetrafluoroethylene resin material provided by the present application include 90-100 parts of polytetrafluoroethylene, preferably 95-100 parts, and in the examples, 95 parts, 96 parts, 97 parts, 98 parts, 99 parts or 100 parts, in terms of mass fraction.
[0027] The preparation raw materials of the polytetrafluoroethylene resin material provided by the present application include 1-10 parts of organic additives, in terms of mass fraction of the polytetrafluoroethylene, and in the examples, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts. In the present application, the perfluoroalkoxy resin is preferably polymerized from tetrafluoroethylene and perfluoroalkoxy vinyl ether. The fluorinated ethylene propylene copolymer is preferably copolymerized from tetrafluoroethylene (TFE) and hexafluoropropylene (HFP). In specific embodiments of the present application, the perfluoroalkoxy resin is preferably Shandong Dongyue DF-16 series fluororesin. The fluorinated ethylene propylene copolymer is preferably Shandong Dongyue DF-10 series fluororesin and / or Shandong Dongyue DF-20 series fluororesin.
[0028] In the present application, when the additive includes perfluoroalkoxy resin and fluorinated ethylene propylene copolymer, the mass fraction of the perfluoroalkoxy resin is preferably 0.5-3 parts, and in the examples, 0.5 parts, 1 part, 2 parts or 3 parts; the fluorinated ethylene propylene copolymer is preferably 0.5-9 parts, and in the examples, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts or 9 parts.
[0029] The preparation raw materials of the polytetrafluoroethylene resin material provided by the present application include 15-25 parts of lubricant, in terms of mass fraction of the polytetrafluoroethylene, and in the examples, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts or 25 parts. In the present application, the lubricant is preferably petroleum ether.
[0030] The present application provides a preparation method of the polytetrafluoroethylene resin material as described in the above technical solutions, including the following steps:
[0031] Mixing the preparation raw materials of the polytetrafluoroethylene resin material to obtain a mixture;
[0032] Placing the mixture in a mold for molding to obtain a green material;
[0033] Sintering the green material to obtain the polytetrafluoroethylene resin material.
[0034] The polytetrafluoroethylene resin material is prepared by mixing raw materials to obtain a mixture. In the present application, the mixing is preferably performed in a container-type mixer. The mixing is preferably performed under stirring. The stirring speed is preferably 15-30 r / min, and the time is preferably 10-20 min.
[0035] After obtaining the mixture, the mixture is placed in a mold to perform molding to obtain a green compact. In the present application, the molding preferably comprises sequentially performing first molding, second molding, and third molding. The pressure of the first molding is preferably 10-20 MPa. The second molding is preferably performed after the first molding is exhausted, and the pressure of the second molding is preferably 25-35 MPa. The pressure of the third molding is preferably 30-40 MPa, and the pressure holding time of the third molding is preferably 5-10 min.
[0036] After obtaining the green compact, the green compact is sintered to obtain the polytetrafluoroethylene resin material. In the present application, the sintering is preferably performed in an oven. The sintering preferably comprises: first temperature holding by heating from room temperature to a first temperature at a first heating rate; then second temperature holding by heating from the first temperature to a second temperature at a second heating rate; and then cooling from the second temperature to room temperature. The first heating rate is preferably 10-20 ℃ / h, the first temperature is preferably 200-250 ℃, the first temperature holding time is preferably 1-2 h, the second heating rate is preferably 10-15 ℃ / h, the second temperature is preferably 350-380 ℃, the second temperature holding time is preferably 30-240 min, and the cooling rate is preferably 10-30 ℃ / h.
[0037] The present application provides the use of the polytetrafluoroethylene resin material in the above technical solution or the polytetrafluoroethylene resin material prepared by the preparation method in the above technical solution in a polytetrafluoroethylene coated sealing gasket.
[0038] The present application provides a sealing gasket coated pad, comprising a EPDM base material, and a polytetrafluoroethylene film coated on the surface of the EPDM base material, wherein the polytetrafluoroethylene film is the polytetrafluoroethylene resin material in the above technical solution or the polytetrafluoroethylene resin material prepared by the preparation method in the above technical solution.
[0039] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.
[0040] Example 1
[0041] The embodiment provides a polytetrafluoroethylene resin material, and preparation raw materials are as follows: 100 parts by mass of polytetrafluoroethylene, 2 parts by mass of PFA, 8 parts by mass of FEP and 25 parts by mass of petroleum ether. The PFA is a fluororesin in a DF-16 series of Shandong Dongyue. The FEP is a fluororesin in a DF-10 series of Shandong Dongyue.
[0042] The embodiment provides a preparation method of a polytetrafluoroethylene resin material, and the method comprises the following steps.
[0043] 1. Mixing: the polytetrafluoroethylene, the PFA, the FEP and the petroleum ether are proportioned as 100 parts by mass, 2 parts by mass, 8 parts by mass and 25 parts by mass respectively; the preparation raw materials are weighed according to the proportion, and are added into a container-type mixing machine, a rotating speed is 30 r / min, and stirring and mixing are performed for 20 min.
[0044] 2. Molding: the preparation raw materials that are uniformly mixed are loaded into a corresponding mold for molding, an initial molding pressure is 20 MPa, and one-time exhaust is performed; then the pressure is increased to 35 MPa for re-molding; finally, the pressure is increased to 40 MPa, and the pressure is maintained for 10 min.
[0045] 3. Sintering: the molding blank is placed into an oven, an oven temperature is slowly increased from room temperature to 250 DEG C, a temperature increasing speed is 20 DEG C / h, after the temperature is increased, 2 h of heat preservation is performed, so that small molecule substances are completely volatilized; then the temperature is increased to 380 DEG C, a temperature increasing speed is 15 DEG C / h, after the temperature is increased, heat preservation is performed for 240 min according to different pipe wall thicknesses; finally, the temperature is slowly decreased to room temperature, and a temperature decreasing speed is 30 DEG C / h.
[0046] 4. The blank is cut according to a required size.
[0047] 5. The blank is turned into a U-shaped diaphragm.
[0048] Embodiment 2
[0049] The embodiment provides a polytetrafluoroethylene resin material, and preparation raw materials are as follows: 100 parts by mass of polytetrafluoroethylene, 2 parts by mass of PFA, 8 parts by mass of FEP and 25 parts by mass of petroleum ether. The PFA is a fluororesin in a DF-16 series of Shandong Dongyue. The FEP is a fluororesin in a DF-10 series of Shandong Dongyue.
[0050] The embodiment provides a preparation method of a polytetrafluoroethylene resin material, and the method comprises the following steps.
[0051] 1. Mixing: the polytetrafluoroethylene, the PFA, the FEP and the petroleum ether are proportioned as 100 parts by mass, 2 parts by mass, 8 parts by mass and 25 parts by mass respectively; the preparation raw materials are weighed according to the proportion, and are added into a container-type mixing machine, a rotating speed is 30 r / min, and stirring and mixing are performed for 20 min.
[0052] 2. Molding: the mixed preparation material is loaded into the corresponding mold for molding, the initial molding pressure is 10 MPa, and the first exhaust is performed. Then the pressure is increased to 25 MPa for the second molding. Finally, the pressure is increased to 30 MPa, and the pressure is maintained for 5 min.
[0053] 3. Sintering: the above molded blank is placed in an oven, the oven temperature is slowly increased from room temperature to 200 °C at a rate of 10 °C / h, and the temperature is maintained for 1 h after the temperature is increased to allow the small molecules to volatilize completely. Then the temperature is increased to 350 °C at a rate of 10 °C / h, and the temperature is maintained for 30 min after the temperature is increased according to different pipe wall thicknesses. Finally, the temperature is slowly decreased to room temperature at a rate of 10 °C / h.
[0054] 4. The blank is cut to the required size.
[0055] 5. Turning into a U-shaped diaphragm.
[0056] Comparative Example 1
[0057] The preparation method is basically the same as that of Example 1, except that:
[0058] This comparative example provides a polytetrafluoroethylene resin material, and the preparation material is: polytetrafluoroethylene 100 parts by mass, petroleum ether 25 parts by mass.
[0059] Figure 1 The actual comparison chart of the PTFE diaphragm prepared in Example 1 and Comparative Example 1 is shown in FIG. 1, Figure 1 The large circle in FIG. 1 is the PTFE diaphragm prepared in Example 1, Figure 1 The small circle in FIG. 1 is the PTFE diaphragm prepared in Comparative Example 1. It can be seen from Figure 1 that the PTFE diaphragm prepared in Comparative Example 1 is white, and the PTFE diaphragm prepared in Example 1 is transparent.
[0060] Comparative Example 2
[0061] The preparation method is basically the same as that of Example 1, except that the composition of the polytetrafluoroethylene resin material is as follows:
[0062] Polytetrafluoroethylene 100 parts by mass, PFA 10 parts by mass, and petroleum ether 25 parts by mass.
[0063] Comparative Example 3
[0064] The preparation method is basically the same as that of Example 1, except that the composition of the polytetrafluoroethylene resin material is as follows:
[0065] Polytetrafluoroethylene 100 parts by mass, FEP 10 parts by mass, and petroleum ether 25 parts by mass.
[0066] Example 3
[0067] The PTFE film prepared by the examples and the comparative examples is used to prepare an E+PTFE coated gasket, and the preparation method comprises: ① sandblasting the surface of the PTFE film to increase its roughness. ② washing with deionized water and blowing dry with hot air. ③ evenly applying the adhesive KEMLOK (205GB) and placing at room temperature for 3 hours. ④ filling the extruded rubber base material into the PTFE film. ⑤ vulcanization on a flat plate vulcanization machine (vulcanization temperature: 175℃, vulcanization pressure: 10MPa; vulcanization time 5min). ⑥ after removing the burrs, the E+PTFE coated gasket product is obtained.
[0068] The rubber base material used in Example 3 is a common EPDM rubber, and the preparation method of the common EPDM rubber base material comprises:
[0069] The common EPDM rubber formula: EPDM rubber Nordel IP 4570 100 parts by mass; carbon black N660 80 parts by mass; ZnO 5 parts by mass; dicumyl peroxide (DCP) 3 parts by mass; paraffin oil 3 parts by mass; processing aid WB422 parts by mass; crosslinking aid TAIC 2 parts by mass; PEG4000 2 parts by mass; antioxidant MB 2 parts by mass; antioxidant RD 2 parts by mass;
[0070] (1) Equipment preparation: start the internal mixer and preheat to 50-60℃.
[0071] (2) Add raw rubber and plasticize: add Nordel IP 4570 (100 parts by mass). Plasticize for 30-60 seconds to cover the rotor with rubber.
[0072] (3) Add small materials: add ZnO, PEG4000, WB42, paraffin oil, and antioxidants (antioxidant MB and antioxidant RD) and mix for 3min.
[0073] (4) Add carbon black: add carbon black N660: when the temperature rises to 110-120℃; add sulfur: add vulcanizing agent DCP and crosslinking aid TAIC, mix for 1min, then adjust the roll gap and pass the mill 3 times, and then cool the sheet.
[0074] Test Example
[0075] The mechanical properties of the PTFE film prepared by the examples and the comparative examples are tested. The test results are shown in Table 1.
[0076] The "tensile strength" and "Shore hardness" in Table 1 are the test results of the "tensile strength" and "Shore hardness" of the PTFE film prepared by the examples and the comparative examples.
[0077] The "plate heat exchanger post water pressure test" in Table 1 is the test result of the PTFE film prepared in the examples and comparative examples after the E+PTFE coated gasket prepared according to Example 3 above is loaded into the plate heat exchanger, and the test pressure is tested in stages of 1.0 MPa, 1.3 MPa, 1.6 MPa, 2.1 MPa, 2.6 MPa, 2.8 MPa, 3.0 MPa, 3.25 MPa, and each stage is pressure maintained for 30 min.
[0078] Table 1 Test results of PTFE film prepared in the examples and comparative examples
[0079]
[0080]
[0081] From the above examples, the present application provides a formula and preparation method of polytetrafluoroethylene resin material. The polytetrafluoroethylene resin material provided by the present application is softer as a PTFE coating material, and the sealing property and pressure bearing capacity of the E+PTFE coated gasket are improved. At the same time, the PTFE coated film is transparent, and after being coated on the EPDM base material and vulcanized, the defects of bubbles between the internal base material and the PTFE coated film can be found, thereby ensuring the quality of the product.
[0082] Although the above examples have made a detailed description of the present application, it is only a part of the examples of the present application, not all the examples, and other examples can be obtained according to the present examples without creativity, and these examples all belong to the protection scope of the present application.
Claims
1. A polytetrafluoroethylene resin material, characterized in that, The preparation materials include the following parts by weight: 90-100 parts of polytetrafluoroethylene, 1-10 parts of organic additives, and 15-25 parts of lubricant; the organic additives include perfluoroalkoxy resins and / or fluorinated ethylene propylene copolymers.
2. The polytetrafluoroethylene resin material according to claim 1, characterized in that, When the additive includes a perfluoroalkoxy resin and a fluorinated ethylene propylene copolymer, the perfluoroalkoxy resin is in the amount of 0.5 to 3 parts by mass, and the fluorinated ethylene propylene copolymer is in the amount of 0.5 to 9 parts by mass.
3. The polytetrafluoroethylene resin material according to claim 1 or 2, characterized in that, The perfluoroalkoxy resin is polymerized from tetrafluoroethylene and perfluoroalkoxy vinyl ether; the fluorinated ethylene propylene copolymer is copolymerized from tetrafluoroethylene and hexafluoropropylene.
4. The polytetrafluoroethylene resin material according to claim 1, characterized in that, The lubricant is petroleum ether.
5. The method for preparing the polytetrafluoroethylene resin material according to any one of claims 1 to 4, characterized in that, Includes the following steps: The raw materials for preparing the polytetrafluoroethylene resin material are mixed to obtain a mixture; The mixture is placed in a mold and pressed to obtain a blank; The preform is sintered to obtain the polytetrafluoroethylene resin material.
6. The preparation method according to claim 5, characterized in that, The mixing is carried out under stirring, with a stirring speed of 15-30 r / min and a time of 10-20 min.
7. The preparation method according to claim 5, characterized in that, The molding process includes a first molding, a second molding, and a third molding in sequence. The pressure of the first molding is 10-20 MPa. After the first molding is degassed, the second molding is performed. The pressure of the second molding is 25-35 MPa. The pressure of the third molding is 30-40 MPa, and the holding time is 5-10 minutes.
8. The preparation method according to claim 5, characterized in that, The sintering process includes: heating from room temperature to a first temperature at a first heating rate and holding for a first time; then heating from the first temperature to a second temperature at a second heating rate and holding for a second time; and then cooling from the second temperature to room temperature; wherein the first heating rate is 10–20°C / h, the first temperature is 200–250°C, the first holding time is 1–2h, the second heating rate is 10–15°C / h, the second temperature is 350–380°C, the second holding time is 30–240min, and the cooling rate is 10–30°C / h.
9. The application of the polytetrafluoroethylene resin material according to any one of claims 1 to 4 or the polytetrafluoroethylene resin material prepared by the preparation method according to any one of claims 5 to 8 in polytetrafluoroethylene coated sealing gaskets.
10. A sealing gasket covering gasket, characterized in that, It includes an EPDM rubber substrate and a polytetrafluoroethylene (PTFE) film covering the surface of the EPDM rubber substrate, wherein the PTFE film is the PTFE resin material according to any one of claims 1 to 4 or the PTFE resin material prepared by the preparation method according to any one of claims 5 to 8.