A high-transparency and high-hardness PTFE pipe and its preparation method

Abstract

The present invention relates to a highly transparent and high-hardness PTFE tube and a preparation method thereof, belonging to the technical field of medical devices. The highly transparent and high-hardness PTFE tube of the present invention, by mass, comprises 70-90 parts of modified polytetrafluoroethylene, 5-20 parts of small-molecule polytetrafluoroethylene, 0.1-10 parts of modified filler, and 15-30 parts of auxiliary agent; the modified polytetrafluoroethylene introduces a perfluoropropyl vinyl ether group during the polymerization process of polytetrafluoroethylene; the preparation method of the modified filler comprises the following steps: adding a lubricant into an alcohol solution and stirring evenly, adding a filler and impregnating for 9 min-11 min, and then drying and curing to obtain the modified filler; the mass ratio of the lubricant to the filler is 0.1-0.5:0.1-10; the molecular weight of the small-molecule polytetrafluoroethylene is 10,000-50,000. The light transmittance of the highly transparent and high-hardness PTFE tube of the present invention can reach more than 80% (wall thickness 0.2 mm), and the Shore hardness can reach more than 65D.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and particularly relates to a highly transparent and high-hardness PTFE tube and a preparation method thereof. Background Art

[0002] Due to the excellent chemical resistance, high temperature resistance, extremely low friction coefficient and excellent biocompatibility of PTFE, it is currently widely used in the medical catheter industry. At present, the mainly used PTFE tubes on the market are still conventional ones, which are mainly prepared by mixing raw materials with additives, drying, extruding and then heating and forming. However, the transparency of conventional PTFE tubes is limited, and most of them are milky white and translucent; it is not convenient for internal tube threading operations, etc. Then, the conventional hardness of PTFE tubes is about 55D (Shore hardness D). In order to avoid bending, the design wall thickness is often increased, which will increase the product size, be unfavorable for product use, and also reduce the light transmittance and increase the finished product. In addition, at present, for conventional highly transparent PTFE, many achieve the standard of transparency by low crystallinity, but the strength and hardness of the products are very low and cannot meet the use requirements. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the problems that the transparency and hardness of PTFE tubes in the prior art cannot meet the use requirements, etc.

[0004] To solve the above technical problems, the present invention provides a highly transparent and high-hardness PTFE tube and a preparation method thereof.

[0005] The first object of the present invention is to provide a highly transparent and high-hardness PTFE tube, which, by mass, comprises 70-90 parts of modified polytetrafluoroethylene, 5-20 parts of small molecule polytetrafluoroethylene, 0.1-10 parts of modified filler, and 15-30 parts of additive;

[0006] The modified polytetrafluoroethylene introduces a perfluoropropyl vinyl ether group during the polymerization process of polytetrafluoroethylene; by introducing short chains, the molecular chain becomes shorter and the molecular weight decreases.

[0007] The preparation method of the modified filler comprises the following steps: adding a lubricant to an alcohol solution and stirring evenly, adding a filler and impregnating for 9 min - 11 min, and then drying and curing to obtain the modified filler; the mass ratio of the lubricant to the filler is 0.1-0.5:0.1-10;

[0008] The molecular weight of the small molecule polytetrafluoroethylene is 10,000 - 50,000.

[0009] In an embodiment of the present invention, the molecular weight of the modified polytetrafluoroethylene is 2 million - 5 million.

[0010] Further, the modified polytetrafluoroethylene is selected from one or more of F302 (Daikin Fluorochemicals), N-PTFE (Daikin Fluorochemicals), Teflon (Chemours), 62XT (Chemours), Fluon (Asahi Kasei AGC Chemicals), and PTFE-CD097E (Asahi Kasei AGC Chemicals).

[0011] In one embodiment of the present invention, the filler is selected from potassium titanate nanoscale whiskers (K2O·6TiO2) and / or alumina A12O3 nanoscale whiskers.

[0012] In one embodiment of the present invention, the auxiliary agent is selected from isoparaffins; the boiling point of the isoparaffin is 110°C - 250°C.

[0013] In one embodiment of the present invention, the isoparaffin is selected from Isopar E (Exxon Chemical) and / or Isopar G (Exxon Chemical).

[0014] Further, the specific gravity (15 / 4°C) of the Isopar E (Exxon Chemical) is 0.723, and the boiling point is 115°C - 139°C.

[0015] Further, the specific gravity (15 / 4°C) of the Isopar G (Exxon Chemical) is 0.750, and the boiling point is 158°C - 173°C.

[0016] In one embodiment of the present invention, the lubricant is selected from 3-aminopropyltriethoxysilane and / or monoalkoxy titanate.

[0017] In one embodiment of the present invention, the stirring speed is 100 r / min - 200 r / min, the stirring temperature is 35°C - 45°C, and the stirring time is 5 h - 8 h.

[0018] In one embodiment of the present invention, the drying and curing temperature is 150°C - 180°C, and the drying and curing time is 5 min - 10 min.

[0019] In one embodiment of the present invention, the alcohol solution is selected from isopropyl alcohol solution.

[0020] The second object of the present invention is to provide a method for preparing the high-transparency and high-hardness PTFE pipe, comprising the following steps:

[0021] S1. Stir the modified polytetrafluoroethylene, small molecule polytetrafluoroethylene, modified filler, and auxiliary agent evenly to obtain a mixture.

[0022] S2. Age the mixture obtained in S1 at 40°C - 50°C for 10 h - 24 h, sieve it, and load it into a mold for pushing and pressing to obtain a tubular blank.

[0023] S3. Perform oil pressure extrusion, curing at 350°C - 450°C, and cooling on the tubular blank described in S2 to obtain the high-transparency and high-hardness PTFE tube.

[0024] In one embodiment of the present invention, in S1, the stirring speed is 500 r / min - 1000 r / min, the stirring temperature is 30°C - 50°C, and the stirring time is 10 min - 30 min.

[0025] In one embodiment of the present invention, in S3, the speed of mold loading and pressing is 45 mm / min - 55 mm / min, the pressing pressure is 1 Mpa - 3 Mpa, and the pressure holding time is 10 min - 30 min.

[0026] In one embodiment of the present invention, in S3, the cooling is rapid cooling with cold water at 5°C - 20°C, and the cooling time is 10 s - 30 s.

[0027] The technical solution of the present invention has the following advantages compared with the prior art:

[0028] (1) For the high-transparency and high-hardness PTFE tube described in the present invention, by adding small-molecular-weight polytetrafluoroethylene (PTFE) to reduce the molecular weight, the regularity of the molecular chain can be decreased. At the same time, due to the presence of network cross-linked branches and the addition of PTFE modified by perfluoropropyl vinyl ether groups, the binding performance between cross-linked network copolymers is strengthened, making it more difficult for it to crystallize. Meanwhile, rapid cooling can further reduce its crystallinity and improve the transparency of the product.

[0029] (2) For the high-transparency and high-hardness PTFE tube described in the present invention, the lubricant is used to modify the filler, significantly improving the lubricity inside and outside the filler, enhancing the interfacial binding property between the filler and polytetrafluoroethylene molecules, and significantly improving the filling and dispersion performance of the filler. At the same time, since the filler has a nanoscale whisker structure, it can penetrate between cross-linked network copolymers, further filling the network cross-linked gaps to form a semi-interpenetrating network polymer, significantly improving the hardness of the PTFE tube.

[0030] (3) The light transmittance of the high-transparency and high-hardness PTFE tube described in the present invention can reach more than 80% (wall thickness 0.2 mm), and the Shore hardness can reach more than 65D. Specific Embodiments

[0031] The following further illustrates the present invention with specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the examples given are not intended to limit the present invention.

[0032] Example 1

[0033] The high-transparency and high-hardness PTFE pipes of the present invention have the following raw material components and their parts by mass:

[0034] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemical Industry, with the brand number F302;

[0035] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours in the United States, with the brand number MP1200;

[0036] 1 part of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0037] 20 parts of auxiliary agent, purchased from Exxon Chemical, with the brand number Isopar E;

[0038] The lubricant is silane coupling agent KH-550;

[0039] Specifically, it includes the following steps:

[0040] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 part of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40 °C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150 °C for 5 min to obtain the modified filler.

[0041] S2. Raw material mixing: After the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through a 20-mesh sieve, they are added to a V-type mixer together with the modified filler, and then the auxiliary agent is added, and they are mixed at a high speed at 500 r / min at 40 °C for 20 min to obtain a mixed material.

[0042] S3. Preparation of tubular blank: Place the mixed material in an environment of 40 °C and cure for 20 h to make the auxiliary agent evenly disperse in the raw materials. After the cured mixed material is sieved through a 100-μm sieve, it is added to a specific mold, and it is pushed and pressed at a speed of 50 mm / min under a pressure of 2 Mpa and kept under pressure for 20 min to obtain a tubular blank.

[0043] S4. Preparation of PTFE pipes: Add the formed tubular blank to an extruder, and through oil pressure extrusion, entangle the raw material molecules to form fibrosis, and then form pipes of the required size. Then, it enters an oven through a device for forming processing at 400 °C, and the cooked pipes are rapidly cooled in 5 °C cold water for 20 s to obtain PTFE pipes (wall thickness is about 0.2 mm).

[0044] Example 2 is basically the same as Example 1, the difference lies in the lubricant

[0045] The high-transparency and high-hardness PTFE pipe of the present invention has the following raw material components and their parts by mass:

[0046] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemical Industry, with the brand number F302;

[0047] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours in the United States, with the brand number MP1200;

[0048] 1 part of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0049] 20 parts of auxiliary agent, purchased from Exxon Chemical, with the brand number Isopar E;

[0050] The lubricant is titanate CS-101;

[0051] Specifically, it includes the following steps:

[0052] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 part of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40 °C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150 °C for 5 min to obtain the modified filler.

[0053] S2. Raw material mixing: After the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through a 20-mesh sieve, they are added to a V-type mixer together with the modified filler, and then the auxiliary agent is added, and they are mixed at a high speed at 500 r / min at 40 °C for 20 min to obtain a mixed material.

[0054] S3. Preparation of tubular blank: Place the mixed material in an environment of 40 °C and cure for 20 h to make the auxiliary agent evenly disperse in the raw materials. After the cured mixed material is sieved through a 100-μm sieve, it is added to a specific mold, and it is pushed and pressed at a speed of 50 mm / min under a pressure of 2 Mpa and kept under pressure for 20 min to obtain a tubular blank.

[0055] S4. Preparation of PTFE pipe: Add the formed tubular blank to an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form a pipe of the required size. Then, it enters an oven through a device and is formed at 400 °C. The cooked pipe is rapidly cooled in 5 °C cold water for 20 s to obtain a PTFE pipe (wall thickness about 0.2 mm).

[0056] Example 3 is basically the same as Example 1, except for the dosages of modified polytetrafluoroethylene, small molecule polytetrafluoroethylene and modified filler

[0057] The high-transparency and high-hardness PTFE pipe of the present invention has the following raw material components and their parts by mass:

[0058] 80 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemicals, with the grade of F302;

[0059] 15 parts of small molecule polytetrafluoroethylene, purchased from Chemours in the United States, with the grade of MP1200;

[0060] 5 parts of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0061] 20 parts of additives, purchased from Exxon Chemical, with the grade of Isopar E;

[0062] The lubricant is silane coupling agent KH-550;

[0063] Specifically, it includes the following steps:

[0064] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 parts of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40 °C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150 °C for 5 min to obtain the modified filler.

[0065] S2. Raw material mixing: After the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through a 20-mesh sieve, they are added to a V-type mixer together with the modified filler, and then the additives are added, and they are mixed at a high speed at 500 r / min at 40 °C for 20 min to obtain a mixed material.

[0066] S3. Preparation of tubular blank: Place the mixed material in an environment at 40 °C and cure for 20 h to make the additives evenly dispersed in the raw materials. After the cured mixed material is sieved through a 100-μm sieve, it is added to a specific mold, and it is pushed and pressed at a speed of 50 mm / min under a pressure of 2 Mpa and kept under pressure for 20 min to obtain a tubular blank.

[0067] S4. Preparation of PTFE pipe: Add the formed tubular blank to an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form a pipe with the required size. Then, it enters an oven through a device and is formed at 400 °C. The cooked pipe is rapidly cooled in 5 °C cold water for 20 s to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0068] Example 4 is basically the same as Example 1, the difference lies in the dosages of modified polytetrafluoroethylene, small molecule polytetrafluoroethylene and modified filler

[0069] For the high-transparency and high-hardness PTFE pipe of the present invention, the raw material components and their parts by mass are as follows:

[0070] 70 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemicals, with the grade of F302;

[0071] 20 parts of small molecule polytetrafluoroethylene, purchased from Chemours in the United States, with the grade of MP1200;

[0072] 10 parts of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0073] 20 parts of additives, purchased from Exxon Chemical, with the grade of Isopar E;

[0074] The lubricant is silane coupling agent KH-550;

[0075] Specifically, it includes the following steps:

[0076] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 parts of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40 °C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150 °C for 5 min to obtain the modified filler.

[0077] S2. Raw material mixing: After the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through 20 meshes, they are added to a V-type mixer together with the modified filler, and then the additives are added, and they are mixed at a high speed at 500 r / min at 40 °C for 20 min to obtain a mixed material.

[0078] S3. Preparation of tubular blank: Place the mixed material in an environment of 40 °C and cure for 20 h to make the additives evenly disperse in the raw materials. After the cured mixed material is sieved through 100 μm, it is added to a specific mold and pushed and pressed at a speed of 50 mm / min under a pressure of 2 Mpa, and the pressure is maintained for 20 min to obtain a tubular blank.

[0079] S4. Preparation of PTFE pipe: Add the formed tubular blank to an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form a pipe with the required size. Then, it enters an oven through a device and is formed at 400 °C. The cooked pipe is rapidly cooled in 5 °C cold water for 20 s to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0080] Example 5 is basically the same as Example 1, the difference lies in the preparation process of the tubular blank

[0081] For the high-transparency and high-hardness PTFE pipe of the present invention, the raw material components and their mass parts are as follows:

[0082] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemicals, with the grade of F302;

[0083] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours in the United States, with the grade of MP1200;

[0084] 1 part of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0085] 20 parts of auxiliary agent, purchased from Exxon Chemical, with the grade of Isopar E;

[0086] The lubricant is silane coupling agent KH-550;

[0087] Specifically, it includes the following steps:

[0088] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 part of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40 °C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150 °C for 5 min to obtain the modified filler.

[0089] S2. Raw material mixing: After the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through a 20-mesh sieve, they are added to a V-type mixer together with the modified filler, and then the auxiliary agent is added, and they are mixed at a high speed at 500 r / min at 40 °C for 20 min to obtain a mixed material.

[0090] S3. Preparation of tubular blank: Place the mixed material in an environment of 40 °C and cure for 24 h to make the auxiliary agent evenly disperse in the raw materials. After the cured mixed material is sieved through a 100-μm sieve, it is added to a specific mold, and it is pushed and pressed at a speed of 50 mm / min under a pressure of 3 Mpa and kept under pressure for 30 min to obtain a tubular blank.

[0091] S4. Preparation of PTFE pipe: Add the formed tubular blank to an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form a pipe with the required size. Then, it enters an oven through a device and is formed at 400 °C. The cooked pipe is rapidly cooled in 5 °C cold water for 20 s to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0092] Example 6 is basically the same as Example 1, the difference lies in the preparation process of the PTFE pipe

[0093] For the high-transparency and high-hardness PTFE pipe of the present invention, the raw material components and their mass parts are as follows:

[0094] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemicals, with the grade of F302;

[0095] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours in the United States, with the grade of MP1200;

[0096] 1 part of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0097] 20 parts of auxiliary agent, purchased from Exxon Chemical, with the brand name Isopar E;

[0098] The lubricant is silane coupling agent KH-550;

[0099] Specifically, it includes the following steps:

[0100] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 part of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40 °C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150 °C for 5 min to obtain the modified filler.

[0101] S2. Raw material mixing: After the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through a 20-mesh sieve, they are added to a V-type mixer together with the modified filler, and then the auxiliary agent is added, and they are mixed at a high speed at 500 r / min at 40 °C for 20 min to obtain a mixed material.

[0102] S3. Preparation of tubular blank: Place the mixed material in an environment at 40 °C and cure for 20 h to make the auxiliary agent evenly disperse in the raw materials. After the cured mixed material is sieved through a 100-μm sieve, it is added to a specific mold, and it is pushed and pressed at a speed of 50 mm / min under a pressure of 2 Mpa and kept under pressure for 20 min to obtain a tubular blank.

[0103] S4. Preparation of PTFE pipe: Add the formed tubular blank to an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form a pipe with the required size. Then, it enters an oven through a device and is formed at 400 °C. The cooked pipe is rapidly cooled in 15 °C cold water for 30 s to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0104] Example 7 is basically the same as Example 1, the difference lies in the filler

[0105] For the high-transparency and high-hardness PTFE pipe of the present invention, the raw material components and their mass parts are as follows:

[0106] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemicals, with the brand name F302;

[0107] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours, USA, with the brand name MP1200;

[0108] 1 part of modified filler, and the filler is alumina A12O3 nanoscale whiskers;

[0109] 20 parts of auxiliary agent, purchased from Exxon Chemical, with the brand name of Isopar E;

[0110] The lubricant is silane coupling agent KH-550;

[0111] Specifically, it includes the following steps:

[0112] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 part of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40 °C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150 °C for 5 min to obtain the modified filler.

[0113] S2. Raw material mixing: After the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through a 20-mesh sieve, they are added to a V-type mixer together with the modified filler, and then the auxiliary agent is added, and they are mixed at a high speed at 500 r / min at 40 °C for 20 min to obtain a mixed material.

[0114] S3. Preparation of tubular blank: Place the mixed material in an environment of 40 °C and cure for 20 h to make the auxiliary agent evenly disperse in the raw materials. After the cured mixed material is sieved through a 100-μm sieve, it is added to a specific mold, and it is pushed and pressed at a speed of 50 mm / min under a pressure of 2 Mpa and kept under pressure for 20 min to obtain a tubular blank.

[0115] S4. Preparation of PTFE pipe: Add the formed tubular blank to an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form a pipe with the required size. Then, it enters an oven through a device and is formed at 400 °C. The cooked pipe is rapidly cooled in 5 °C cold water for 20 s to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0116] The difference between Comparative Example 1 and Example 1 is that the filler is not subjected to modification treatment

[0117] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemical Co., Ltd., with the brand name of F302;

[0118] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours Company FC, LLC, with the brand name of MP1200;

[0119] 1 part of filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0120] 20 parts of auxiliary agent, purchased from Exxon Chemical, with the brand name of Isopar E;

[0121] The lubricant is silane coupling agent KH-550;

[0122] Specifically, it includes the following steps:

[0123] S1. Raw material mixing: After passing through a 20-mesh sieve, the modified polytetrafluoroethylene and small molecule polytetrafluoroethylene are added to a V-type mixer together with the filler, and then the auxiliary agent is added. They are mixed at a high speed at 40°C for 20 minutes at a speed of 500 r / min to obtain a mixed material.

[0124] S2. Preparation of tubular blank: The mixed material is placed in an environment at 40°C for 20 hours to cure, so that the auxiliary agent is evenly dispersed in the raw materials. After the cured mixed material passes through a 100-μm sieve, it is added to a specific mold and pushed and pressed at a pressure of 2 Mpa at a speed of 50 mm / min, and the pressure is maintained for 20 minutes to obtain a tubular blank.

[0125] S3. Preparation of PTFE pipe: The formed tubular blank is added to an extruder, and the raw material molecules are entangled through oil pressure extrusion to form fibrosis, and then formed into a pipe with the required size. Then, it enters an oven through a device for forming processing at 400°C, and the cooked pipe is rapidly cooled in 5°C cold water for 20 s to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0126] The difference between Comparative Example 2 and Example 1 is that small molecule polytetrafluoroethylene is not added.

[0127] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemicals, with the brand number F302;

[0128] 1 part of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0129] 20 parts of auxiliary agent, purchased from Exxon Chemical, with the brand number Isopar E;

[0130] The lubricant is silane coupling agent KH-550;

[0131] Specifically, it includes the following steps:

[0132] S1. Preparation of modified filler: Isopropanol and deionized water are added to 0.2 part of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), and they are stirred at 40°C at a speed of 100 r / min for 5 hours until the solution is clear and transparent. Then 1 part of filler is added and impregnated for 10 minutes, and then taken out and dried and cured at 150°C for 5 minutes to obtain the modified filler.

[0133] S2. Raw material mixing: After passing through a 20-mesh sieve, the modified polytetrafluoroethylene is added to a V-type mixer together with the modified filler, and then the auxiliary agent is added. They are mixed at a high speed at 40°C for 20 minutes at a speed of 500 r / min to obtain a mixed material.

[0134] S3. Preparation of tubular blank: The mixture is placed in an environment at 40°C for 20 hours to allow the additives to be evenly dispersed in the raw materials. After the matured mixture is sieved through a 100-μm sieve, it is added into a specific mold and pushed under a pressure of 2 MPa at a speed of 50 mm / min, and the pressure is maintained for 20 minutes to obtain a tubular blank.

[0135] S4. Preparation of PTFE pipe: The formed tubular blank is added to an extruder, and the raw material molecules are entangled through oil pressure extrusion to form fibrosis, and then formed into a pipe of the required size. Then, it enters an oven through a device for forming processing at 400°C, and the cooked pipe is rapidly cooled in 5°C cold water for 20 seconds to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0136] The difference between Comparative Example 3 and Example 1 is that polytetrafluoroethylene is not modified.

[0137] 90 parts of polytetrafluoroethylene, purchased from DuPont, USA, with the brand number 6CX;

[0138] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours, USA, with the brand number MP1200;

[0139] 1 part of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0140] 20 parts of additives, purchased from Exxon Chemical, with the brand number Isopar E;

[0141] The lubricant is silane coupling agent KH-550;

[0142] Specifically, it includes the following steps:

[0143] S1. Preparation of modified filler: Isopropanol and deionized water are added to 0.2 part of the lubricant (the mass ratio of the lubricant, isopropanol and deionized water is 3:1:6), and stirred at 40°C at a speed of 100 r / min for 5 hours until the solution is clear and transparent. Then, 1 part of the filler is added and impregnated for 10 minutes, and then taken out and dried and cured at 150°C for 5 minutes to obtain the modified filler.

[0144] S2. Raw material mixing: After polytetrafluoroethylene and small molecule polytetrafluoroethylene are sieved through a 20-mesh sieve, they are added to a V-type mixer together with the modified filler, and then the additives are added, and mixed at a high speed at 40°C at a speed of 500 r / min for 20 minutes to obtain a mixture.

[0145] S3. Preparation of tubular blank: Place the mixture in an environment at 40°C for 20 h to cure it, so that the additives are evenly dispersed in the raw materials. After screening the cured mixture through a 100-μm sieve, add it into a specific mold, and push and press it at a speed of 50 mm / min under a pressure of 2 MPa, and keep the pressure for 20 min to obtain a tubular blank.

[0146] S4. Preparation of PTFE pipe: Add the formed tubular blank into an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form a pipe with the required size. Then, enter the oven through the device for forming at 400°C, and rapidly cool the cooked pipe with cold water at 5°C for 20 s to obtain a PTFE pipe (wall thickness is about 0.2 mm).

[0147] The difference between Comparative Example 4 and Example 1 lies in the preparation of PTFE pipes.

[0148] 90 parts of modified polytetrafluoroethylene, purchased from Daikin Fluorochemical Co., Ltd., with the brand number F302;

[0149] 9 parts of small molecule polytetrafluoroethylene, purchased from Chemours Company, USA, with the brand number MP1200;

[0150] 1 part of modified filler, and the filler is potassium titanate nanoscale whiskers (K2O·6TiO2);

[0151] 20 parts of additives, purchased from Exxon Chemical Co., Ltd., with the brand number Isopar E;

[0152] The lubricant is silane coupling agent KH-550;

[0153] Specifically, it includes the following steps:

[0154] S1. Preparation of modified filler: Add isopropanol and deionized water to 0.2 part of lubricant (the mass ratio of lubricant, isopropanol and deionized water is 3:1:6), stir at a speed of 100 r / min at 40°C for 5 h until the solution is clear and transparent, then add 1 part of filler and impregnate for 10 min, and then take it out and dry and cure at 150°C for 5 min to obtain the modified filler.

[0155] S2. Raw material mixing: After screening modified polytetrafluoroethylene and small molecule polytetrafluoroethylene through a 20-mesh sieve, add them to a V-type mixer, then add additives, and mix at a high speed of 500 r / min at 40°C for 20 min to obtain a mixture.

[0156] S3. Preparation of tubular blank: Place the mixture in an environment at 40°C for 20 h to allow the additives to be evenly dispersed in the raw materials. After screening the matured mixture through a 100-μm sieve, add it into a specific mold and push it under a pressure of 2 MPa at a speed of 50 mm / min, and keep the pressure for 20 min to obtain a tubular blank.

[0157] S4. Preparation of PTFE pipes: Add the formed tubular blank into an extruder, and make the raw material molecules entangle with each other through oil pressure extrusion to form fibrosis, and then form pipes with required dimensions. Then, enter the oven through the device for forming at 400°C, and naturally cool the cooked pipes to room temperature through the air to obtain PTFE pipes (wall thickness is about 0.2 mm).

[0158] Test example

[0159] Test the hardness and transparency of the materials prepared in Examples 1-7 and Comparative Examples 1-4:

[0160] (1) Hardness test: Refer to the test method of Shore hardness of plastics in GB 2411-80; the instrument is a Shore D hardness measuring instrument; the instrument model is HTS-800; the manufacturer is Shanghai Yizong Precision.

[0161] (2) Transparency test: Refer to the test method of light transmittance and haze of transparent plastics in GB / T 2410-2008; the instrument model is TH-110 haze meter; the type is haze meter / light transmittance meter; the manufacturer is Hangzhou Caipu.

[0162] Table 1 shows the relevant data finally measured:

[0163] Table 1

[0164]

[0165]

[0166] It can be seen from Table 1 that the transparency of modified PTFE is significantly improved compared with that of conventional PTFE. Both potassium titanate nanoscale whiskers and alumina A12O3 nanoscale whiskers as modified fillers can improve the hardness of the pipes. Among them, the improvement effect of alumina is the most obvious, but the influence on transparency is also relatively large. Therefore, the addition amount of alumina should not be too much. It can be seen that both lubricants 3-aminopropyltriethoxysilane and / or monoalkoxy titanate can play a good internal and external lubricating role for the fillers, improve the dispersion of the fillers, and improve the hardness performance. In addition, during the preparation process, the faster the cooling speed and the lower the cooling temperature, the better the transparency of the pipes.

[0167] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A high-transparency and high-hardness PTFE pipe, characterized in that, By mass parts, it includes 70 - 90 parts of modified polytetrafluoroethylene, 5 - 20 parts of small molecule polytetrafluoroethylene, 0.1 - 10 parts of modified filler, and 15 - 30 parts of additives; The modified polytetrafluoroethylene introduces perfluoropropyl vinyl ether groups during the polymerization process of polytetrafluoroethylene; The preparation method of the modified filler includes the following steps: adding a lubricant to an alcohol solution and stirring evenly, adding the filler and impregnating for 9 min - 11 min, then drying and curing to obtain the modified filler; the mass ratio of the lubricant to the filler is 0.1 - 0.5:0.1 - 10; the filler is selected from potassium titanate nanoscale whiskers and / or alumina nanoscale whiskers; The molecular weight of the small molecule polytetrafluoroethylene is 10,000 - 50,000; The preparation method of the high - transparency and high - hardness PTFE pipe includes the following steps, S1. Stir the modified polytetrafluoroethylene, small molecule polytetrafluoroethylene, modified filler and additives evenly to obtain a mixture; S2. Cure the mixture obtained in S1 at 40°C - 50°C for 10 h - 24 h, sieve it, load it into a mold and push - press it to obtain a tubular blank; S3. Perform oil - pressure extrusion, cure at 350°C - 450°C, and cool the tubular blank obtained in S2 to obtain the high - transparency and high - hardness PTFE pipe; the cooling is carried out by rapid cooling with cold water at 5°C - 20°C, and the cooling time is 10 s - 30 s.

2. The highly transparent and high-hardness PTFE pipe according to claim 1, wherein The molecular weight of the modified polytetrafluoroethylene is 2 million - 5 million.

3. The high-transparency and high-hardness PTFE pipe according to claim 1, wherein The additives are selected from isoparaffins; the boiling point of the isoparaffins is 110°C - 250°C.

4. The high-transparency and high-hardness PTFE pipe according to claim 1, wherein, The lubricant is selected from 3 - aminopropyltriethoxysilane and / or mono - alkoxy titanate.

5. The high-transparency and high-hardness PTFE pipe according to claim 1, characterized in that, The stirring speed is 100 r / min - 200 r / min, the stirring temperature is 35°C - 45°C, and the stirring time is 5 h - 8 h.

6. The high-transparency and high-hardness PTFE pipe according to claim 1, wherein The drying and curing temperature is 150°C - 180°C, and the drying and curing time is 5 min - 10 min.

7. The preparation method of the highly transparent and highly hard PTFE pipe according to any one of claims 1-6, characterized in that, It includes the following steps, S1. Stir the modified polytetrafluoroethylene, small molecule polytetrafluoroethylene, modified filler and additives evenly to obtain a mixture; S2. Cure the mixture obtained in S1 at 40°C - 50°C for 10 h - 24 h, sieve it, load it into a mold and push - press it to obtain a tubular blank; S3. Perform oil - pressure extrusion, cure at 350°C - 450°C, and cool the tubular blank obtained in S2 to obtain the high - transparency and high - hardness PTFE pipe; the cooling is carried out by rapid cooling with cold water at 5°C - 20°C, and the cooling time is 10 s - 30 s.

8. The preparation method of the highly transparent and high-hardness PTFE pipe according to claim 7, characterized in that, In S1, the stirring speed is 500 r / min - 1000 r / min, the stirring temperature is 30°C - 50°C, and the stirring time is 10 min - 30 min.

9. The preparation method of the high-transparency and high-hardness PTFE pipe according to claim 7, characterized in that, In S3, the speed of loading into the mold and pushing - press is 45 mm / min - 55 mm / min, the pushing - press pressure is 1 Mpa - 3 Mpa, and the pressure - holding time is 10 min - 30 min.

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