Method for continuously etching PTFE (Polytetrafluoroethylene) tube

Abstract

The invention discloses a method for continuously etching a PTFE (Polytetrafluoroethylene) tube, and relates to the technical field of PTFE tubes. The method comprises four main steps of pre-cleaning, etching, multi-stage rinsing and drying. Firstly, oil stains and impurities on the surface of the PTFE pipe are removed through a cleaning device; then, the pipe is continuously conveyed into an etching tank containing a sodium naphthalene etching agent (containing an etching synergist) for etching, and the etching depth is adjusted by controlling the passing speed and the concentration of the etching solution; after etching, the pipe enters a multi-stage rinsing tank, and residual etching liquid is efficiently removed by utilizing reverse water flow. And finally, moisture is thoroughly removed through a hot air drying device, so that the surface of the PTFE pipe achieves uniform roughness, and preparation is made for subsequent treatment procedures.

Description

Technical Field

[0001] The invention relates to the technical field of PTFE tubes, in particular to a method for continuously etching a PTFE tube. Background Art

[0002] Polytetrafluoroethylene (PTFE) is a high-performance engineering plastic that is widely used in chemical, electronic, aerospace, medical and other industrial fields due to its excellent chemical stability, high temperature resistance, low friction coefficient and extremely low surface energy. PTFE material exhibits strong corrosion resistance in most chemical environments and is not corroded by strong acids, strong alkalis, solvents and other chemicals. In addition, PTFE has a very wide operating temperature range, from -200°C to 260°C, and can maintain excellent performance under extreme temperature conditions. It is precisely because of these characteristics that PTFE is widely used in the manufacture of products such as seals, pipes, insulation materials and anti-corrosion coatings.

[0003] However, although PTFE material has many excellent properties, its surface energy is extremely low, resulting in poor bonding with other materials. For example, in processes such as coating, bonding or painting, it is difficult for the PTFE surface to effectively adhere to other materials. This characteristic poses a challenge in some applications because in order to ensure the functionality and reliability of the product, the PTFE surface must be treated to improve its surface adhesion. For this reason, surface etching is usually used to change the surface chemical structure and morphology of the PTFE material, increase the surface roughness, and thus enhance its adhesion to other materials.

[0004] The traditional PTFE etching process is usually an intermittent process, that is, the PTFE product is immersed in the etching solution for a certain period of time, then taken out, rinsed and dried. This process has several problems:

[0005] Low efficiency: Intermittent etching processes usually require a lot of manpower and time, with low production efficiency, and cannot meet the needs of large-scale industrial production. The processing volume of each batch is limited, resulting in insufficient production capacity.

[0006] Complex operation: During the intermittent etching process, operators need to frequently perform manual operations, including soaking, removing, rinsing and drying steps. The operation is complex and prone to errors, increasing the risk of unstable quality.

[0007] Uneven etching effect: Due to the uncontrollability of manual operation and the difficulty in accurately controlling the processing time, the effect of intermittent etching is often uneven, which can easily lead to inconsistent etching depth on the PTFE surface and affect the quality of subsequent processes.

[0008] Environmental and safety issues: Traditional etching solutions usually contain highly corrosive and toxic chemicals, such as a mixture of sodium hydroxide and metallic sodium. These chemicals not only pose a threat to the health of operators, but also pose a potential risk of pollution to the environment. Therefore, strict safety measures and environmental protection treatment are required during the operation.

[0009] Based on the above problems, it is urgent to develop a process method that can achieve continuous etching of PTFE tubes to improve production efficiency, simplify the operation process, ensure the consistency of etching effects, and reduce harm to the environment and operators. By achieving continuous etching of PTFE tubes, the production line can maintain uninterrupted operation, greatly improving production capacity, and it is also beneficial to control the etching quality in industrial production and ensure the consistency and stability of each batch of products.

[0010] Therefore, the present invention proposes a method for continuously etching a PTFE tube, which enables the surface etching of the PTFE tube to be carried out in an efficient, stable and environmentally friendly manner by adopting automated control and a continuous process flow, thereby meeting the needs of modern industry for large-scale, high-quality production. Summary of the invention

[0011] The present invention provides a method for continuously etching a PTFE tube to solve at least one technical problem in the above-mentioned background technology.

[0012] In order to solve the above technical problems, the embodiments of the present invention disclose the following technical solutions:

[0013] A method for continuously etching a PTFE tube, the operating steps of which are:

[0014] Step 1: Cleaning: Pre-clean the PTFE tube using a cleaning device to remove oil and impurities on the surface to prepare for the subsequent etching process.

[0015] Step 2: Etching: The PTFE tube is continuously conveyed to an etching tank through a conveying device. The etching tank contains a sodium naphthalene etchant. An etching enhancer is added to the sodium naphthalene etchant to dissolve evenly. The PTFE tube passes through the etching solution at a certain speed to control the residence time of the PTFE tube in the etching solution. The etching time and etching solution concentration are adjustable to meet different etching depth requirements.

[0016] Step 3: Rinsing: The etched PTFE tube enters multiple rinsing tanks for multi-stage rinsing to remove the etching solution remaining on the surface. The water flow direction in the rinsing tank is opposite to the movement direction of the PTFE tube to improve the rinsing effect.

[0017] Step 4 Drying: The rinsed PTFE tube is dried by a hot air drying device to ensure that there is no residual moisture on the surface of the PTFE tube. The surface of the dried PTFE tube has a uniform roughness and is suitable for subsequent processing procedures.

[0018] According to an embodiment of the present invention, the cleaning uses deionized water, the cleaning temperature is controlled between 40° C. and 60° C., and the cleaning time is 5 to 10 minutes.

[0019] According to an embodiment of the present invention, the etching enhancer is added in an amount of 1-5% by mass of the sodium naphthalene etchant.

[0020] According to an embodiment of the present invention, the preparation method of the etching enhancer is:

[0021] Under a nitrogen atmosphere, 32.5-65 parts of 2,6-naphthalene disulfonyl chloride, 21-42 parts of 3-hydroxy-1-adamantane methyl vinyl ether and 0.02-0.4 parts of 1-ferrocenylethanol are placed in a round-bottom flask by weight, 200-300 parts of tetrahydrofuran are added as a solvent, and then 0.2-0.6 parts of triethylamine are added as a catalyst. The reaction mixture is cooled to 0-10°C in an ice bath and stirred for 1-3 hours, then slowly heated to room temperature and stirred for 20-30 hours. After the reaction is completed, the product is extracted with water, the organic layer is dried with anhydrous sodium sulfate, and the tetrahydrofuran is evaporated to obtain an etching enhancer.

[0022] According to an embodiment of the present invention, the temperature of the etching solution is controlled between 60°C and 70°C.

[0023] According to an embodiment of the present invention, the residence time of the PTFE tube in the etching solution is 1 to 3 minutes, and the speed range of the PTFE tube conveyor belt is 10 to 50 cm / min.

[0024] According to an embodiment of the present invention, the rinsing water flow rate is controlled at 2 to 4 L / min, the rinsing water temperature is controlled between 25° C. and 35° C., and the rinsing time is 2 to 5 minutes.

[0025] According to an embodiment of the present invention, the drying temperature is controlled between 90° C. and 110° C., the wind speed of the hot air nozzle is controlled between 5 and 15 m / s, and the distance between the nozzle and the PTFE tube is 10 to 20 cm.

[0026] Reaction mechanism:

[0027] The reaction involves 2,6-naphthalene disulfonyl chloride, which has an active sulfonyl chloride group and is easy to undergo esterification with hydroxyl-containing compounds. In the reaction, 3-hydroxy-1-adamantane methyl vinyl ether and 1-ferrocenyl ethanol each provide a hydroxyl group to react with the sulfonyl chloride group through nucleophilic attack. The hydroxyl groups in 3-hydroxy-1-adamantane methyl vinyl ether and 1-ferrocenyl ethanol initiate nucleophilic attacks on one and the other sulfonyl chloride groups in 2,6-naphthalene disulfonyl chloride, respectively. The sulfonyl chloride group is replaced by the nucleophilic hydroxyl group, followed by the release of chloride ions to form the corresponding sulfonate ester bond link. The final result is a naphthalene sulfonate compound containing both adamantane and ferrocenyl groups. The product has amphiphilic properties (both hydrophilic and hydrophobic properties), which makes it effective in improving interfacial activity when used as an etchant enhancer.

[0028] Technical effect:

[0029] Compared with traditional methods, this method has the following advantages:

[0030] 1. Improved etching performance:

[0031] The newly synthesized naphthalene sulfonate compound containing adamantane and ferrocene acts as an etchant enhancer, which can react more effectively with the material to be etched, thereby improving the etching accuracy and rate. The sulfonate group in the enhancer may help to better dissolve the oxide layer on the metal surface, exposing a fresh metal surface for further chemical reactions.

[0032] 2. Improve material compatibility:

[0033] The introduced adamantane and ferrocene groups increase the complexity and stability of the molecule, which may provide better material compatibility during chemical etching. These groups may also provide additional electronic effects or steric effects, affecting the chemical reaction dynamics during etching. DETAILED DESCRIPTION

[0034] The present invention will be described in further detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0035] Example 1

[0036] A method for continuously etching a PTFE tube, the operating steps of which are:

[0037] Step 1: Cleaning: Pre-clean the PTFE tube using a cleaning device to remove oil and impurities on the surface to prepare for the subsequent etching process.

[0038] Step 2: Etching: The PTFE tube is continuously conveyed to an etching tank through a conveying device. The etching tank contains a sodium naphthalene etchant. An etching enhancer is added to the sodium naphthalene etchant to dissolve evenly. The PTFE tube passes through the etching solution at a certain speed to control the residence time of the PTFE tube in the etching solution. The etching time and etching solution concentration are adjustable to meet different etching depth requirements.

[0039] Step 3: Rinsing: The etched PTFE tube enters multiple rinsing tanks for multi-stage rinsing to remove the etching solution remaining on the surface. The water flow direction in the rinsing tank is opposite to the movement direction of the PTFE tube to improve the rinsing effect.

[0040] Step 4 Drying: The rinsed PTFE tube is dried by a hot air drying device to ensure that there is no residual moisture on the surface of the PTFE tube. The surface of the dried PTFE tube has a uniform roughness and is suitable for subsequent processing procedures.

[0041] Deionized water was used for cleaning, the cleaning temperature was controlled at 40° C., and the cleaning time was 5 minutes.

[0042] The amount of the etching enhancer added is 1% by mass of the sodium naphthalene etching agent.

[0043] The preparation method of the etching synergist is:

[0044] Under a nitrogen atmosphere, 32.5 g of 2,6-naphthalene disulfonyl chloride, 21 g of 3-hydroxy-1-adamantane methyl vinyl ether, and 0.02 g of 1-ferrocenylethanol were placed in a round-bottom flask, 200 g of tetrahydrofuran was added as a solvent, and then 0.2 g of triethylamine was added as a catalyst. The reaction mixture was cooled to 0°C in an ice bath and stirred for 1 hour, then slowly heated to room temperature and continued to stir for 20 hours. After the reaction was completed, the product was extracted with water, the organic layer was dried over anhydrous sodium sulfate, and the tetrahydrofuran was evaporated to obtain an etching enhancer.

[0045] The temperature of the etching solution is controlled at 60°C.

[0046] The PTFE tube stays in the etching solution for 1 minute, and the PTFE tube conveyor belt speed range is 10 cm / min.

[0047] The rinsing water flow rate is controlled at 2 L / min, the rinsing water temperature is controlled at 25° C., and the rinsing time is 2 minutes.

[0048] The drying temperature was controlled at 90° C., the wind speed of the hot air nozzle was controlled at 5 m / s, and the distance between the nozzle and the PTFE tube was 10 cm.

[0049] Example 2

[0050] A method for continuously etching a PTFE tube, the operating steps of which are:

[0051] Step 1: Cleaning: Pre-clean the PTFE tube using a cleaning device to remove oil and impurities on the surface to prepare for the subsequent etching process.

[0052] Step 2: Etching: The PTFE tube is continuously conveyed to an etching tank through a conveying device. The etching tank contains a sodium naphthalene etchant. An etching enhancer is added to the sodium naphthalene etchant to dissolve evenly. The PTFE tube passes through the etching solution at a certain speed to control the residence time of the PTFE tube in the etching solution. The etching time and etching solution concentration are adjustable to meet different etching depth requirements.

[0053] Step 3: Rinsing: The etched PTFE tube enters multiple rinsing tanks for multi-stage rinsing to remove the etching solution remaining on the surface. The water flow direction in the rinsing tank is opposite to the movement direction of the PTFE tube to improve the rinsing effect.

[0054] Step 4 Drying: The rinsed PTFE tube is dried by a hot air drying device to ensure that there is no residual moisture on the surface of the PTFE tube. The surface of the dried PTFE tube has a uniform roughness and is suitable for subsequent processing procedures.

[0055] Deionized water was used for the cleaning, the cleaning temperature was controlled at 50° C., and the cleaning time was 7 minutes.

[0056] The amount of the etching enhancer added is 2.5% by mass of the sodium naphthalene etching agent.

[0057] The preparation method of the etching synergist is:

[0058] Under a nitrogen atmosphere, 42.5 g of 2,6-naphthalene disulfonyl chloride, 29 g of 3-hydroxy-1-adamantane methyl vinyl ether, and 0.15 g of 1-ferrocenylethanol were placed in a round-bottom flask, 225 g of tetrahydrofuran was added as a solvent, and then 0.3 g of triethylamine was added as a catalyst. The reaction mixture was cooled to 5 ° C in an ice bath and stirred for 2 hours, then slowly heated to room temperature and continued to stir for 25 hours. After the reaction was completed, the product was extracted with water, the organic layer was dried with anhydrous sodium sulfate, and the tetrahydrofuran was evaporated to obtain an etching enhancer.

[0059] The temperature of the etching solution is controlled at 65°C.

[0060] The PTFE tube stays in the etching solution for 2 minutes, and the PTFE tube conveyor belt speed range is 25 cm / min.

[0061] The rinsing water flow rate is controlled at 3 L / min, the rinsing water temperature is controlled at 30° C., and the rinsing time is 3 minutes.

[0062] The drying temperature was controlled at 100° C., the wind speed of the hot air nozzle was controlled at 10 m / s, and the distance between the nozzle and the PTFE tube was 15 cm.

[0063] Example 3

[0064] A method for continuously etching a PTFE tube, the operating steps of which are:

[0065] Step 1: Cleaning: Pre-clean the PTFE tube using a cleaning device to remove oil and impurities on the surface to prepare for the subsequent etching process.

[0066] Step 2: Etching: The PTFE tube is continuously conveyed to an etching tank through a conveying device. The etching tank contains a sodium naphthalene etchant. An etching enhancer is added to the sodium naphthalene etchant to dissolve evenly. The PTFE tube passes through the etching solution at a certain speed to control the residence time of the PTFE tube in the etching solution. The etching time and etching solution concentration are adjustable to meet different etching depth requirements.

[0067] Step 3: Rinsing: The etched PTFE tube enters multiple rinsing tanks for multi-stage rinsing to remove the etching solution remaining on the surface. The water flow direction in the rinsing tank is opposite to the movement direction of the PTFE tube to improve the rinsing effect.

[0068] Step 4 Drying: The rinsed PTFE tube is dried by a hot air drying device to ensure that there is no residual moisture on the surface of the PTFE tube. The surface of the dried PTFE tube has a uniform roughness and is suitable for subsequent processing procedures.

[0069] Deionized water was used for the cleaning, the cleaning temperature was controlled at 50° C., and the cleaning time was 8 minutes.

[0070] The amount of the etching enhancer added is 4% by mass of the sodium naphthalene etching agent.

[0071] The preparation method of the etching synergist is:

[0072] Under a nitrogen atmosphere, 52 g of 2,6-naphthalene disulfonyl chloride, 36 g of 3-hydroxy-1-adamantane methyl vinyl ether, and 0.3 g of 1-ferrocenylethanol were placed in a round-bottom flask, 250 g of tetrahydrofuran was added as a solvent, and then 0.5 g of triethylamine was added as a catalyst. The reaction mixture was cooled to 5 ° C in an ice bath and stirred for 2 hours, then slowly heated to room temperature and continued to stir for 25 hours. After the reaction was completed, the product was extracted with water, the organic layer was dried with anhydrous sodium sulfate, and the tetrahydrofuran was evaporated to obtain an etching enhancer.

[0073] The temperature of the etching solution is controlled at 65°C.

[0074] The PTFE tube stays in the etching solution for 2 minutes, and the PTFE tube conveyor belt speed range is 40 cm / min.

[0075] The rinsing water flow rate is controlled at 3 L / min, the rinsing water temperature is controlled at 30° C., and the rinsing time is 4 minutes.

[0076] The drying temperature was controlled at 100° C., the wind speed of the hot air nozzle was controlled at 10 m / s, and the distance between the nozzle and the PTFE tube was 15 cm.

[0077] Example 4

[0078] A method for continuously etching a PTFE tube, the operating steps of which are:

[0079] Step 1: Cleaning: Pre-clean the PTFE tube using a cleaning device to remove oil and impurities on the surface to prepare for the subsequent etching process.

[0080] Step 2: Etching: The PTFE tube is continuously conveyed to an etching tank through a conveying device. The etching tank contains a sodium naphthalene etchant. An etching enhancer is added to the sodium naphthalene etchant to dissolve evenly. The PTFE tube passes through the etching solution at a certain speed to control the residence time of the PTFE tube in the etching solution. The etching time and etching solution concentration are adjustable to meet different etching depth requirements.

[0081] Step 3: Rinsing: The etched PTFE tube enters multiple rinsing tanks for multi-stage rinsing to remove the etching solution remaining on the surface. The water flow direction in the rinsing tank is opposite to the movement direction of the PTFE tube to improve the rinsing effect.

[0082] Step 4 Drying: The rinsed PTFE tube is dried by a hot air drying device to ensure that there is no residual moisture on the surface of the PTFE tube. The surface of the dried PTFE tube has a uniform roughness and is suitable for subsequent processing procedures.

[0083] The cleaning was performed using deionized water, the cleaning temperature was controlled at 60° C., and the cleaning time was 10 minutes.

[0084] The amount of the etching enhancer added is 5% by mass of the sodium naphthalene etching agent.

[0085] The preparation method of the etching synergist is:

[0086] Under a nitrogen atmosphere, 65 g of 2,6-naphthalene disulfonyl chloride, 42 g of 3-hydroxy-1-adamantane methyl vinyl ether, and 0.4 g of 1-ferrocenylethanol were placed in a round-bottom flask, 300 g of tetrahydrofuran was added as a solvent, and then 0.6 g of triethylamine was added as a catalyst. The reaction mixture was cooled to 10 ° C in an ice bath and stirred for 3 hours, then slowly heated to room temperature and continued to stir for 30 hours. After the reaction was completed, the product was extracted with water, the organic layer was dried with anhydrous sodium sulfate, and the tetrahydrofuran was evaporated to obtain an etching enhancer.

[0087] The temperature of the etching solution is controlled at 70°C.

[0088] The PTFE tube stays in the etching solution for 3 minutes, and the PTFE tube conveyor belt speed range is 50 cm / min.

[0089] The rinsing water flow rate is controlled at 4 L / min, the rinsing water temperature is controlled at 35° C., and the rinsing time is 5 minutes.

[0090] The drying temperature was controlled at 110° C., the wind speed of the hot air nozzle was controlled at 15 m / s, and the distance between the nozzle and the PTFE tube was 20 cm.

[0091] Comparative Example 1

[0092] The only difference between this example and Example 1 is that no etching enhancer is added to the etching solution.

[0093] Comparative Example 2

[0094] The only difference between this example and Example 1 is that 1-ferrocenylethanol is not added during the preparation of the etching enhancer.

[0095] Test method:

[0096] 1. Surface roughness: Surface roughness tester, using a diamond probe with a probe radius of 2 μm;

[0097] 2. 90° peel tester: Set the peel angle to 90° and the peel speed to 10mm / min.

[0098] Test results:

[0099]

[0100] Through the test results of the above embodiments and comparative examples, it can be seen that the continuous etching method of the present invention has significant advantages in terms of surface roughness, adhesion and cleanliness.

[0101] The applicant declares that the present invention is further illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for continuously etching a PTFE tube, the operating steps of which are: Step 1: Cleaning: Pre-clean the PTFE tube using a cleaning device to remove oil and impurities on the surface to prepare for the subsequent etching process. Step 2: Etching: The PTFE tube is continuously conveyed to an etching tank through a conveying device. The etching tank contains a sodium naphthalene etchant. An etching enhancer is added to the sodium naphthalene etchant to dissolve evenly. The PTFE tube passes through the etching solution at a certain speed to control the residence time of the PTFE tube in the etching solution. The etching time and etching solution concentration are adjustable to meet different etching depth requirements. Step 3: Rinsing: The etched PTFE tube enters multiple rinsing tanks for multi-stage rinsing to remove the etching solution remaining on the surface. The water flow direction in the rinsing tank is opposite to the movement direction of the PTFE tube to improve the rinsing effect. Step 4 Drying: The rinsed PTFE tube is dried by a hot air drying device to ensure that there is no residual moisture on the surface of the PTFE tube. The surface of the dried PTFE tube has a uniform roughness and is suitable for subsequent processing procedures.

2. A method for continuously etching a PTFE tube according to claim 1, characterized in that: The cleaning is carried out using deionized water, the cleaning temperature is controlled between 40° C. and 60° C., and the cleaning time is 5 to 10 minutes.

3. A method for continuously etching a PTFE tube according to claim 1, characterized in that: The amount of the etching enhancer added is 1-5% by mass of the sodium naphthalene etching agent.

4. A method for continuously etching a PTFE tube according to claim 1, characterized in that: The preparation method of the etching synergist is: Under a nitrogen atmosphere, 32.5-65 parts of 2,6-naphthalene disulfonyl chloride, 21-42 parts of 3-hydroxy-1-adamantane methyl vinyl ether and 0.02-0.4 parts of 1-ferrocenylethanol are placed in a round-bottom flask by weight, 200-300 parts of tetrahydrofuran are added as a solvent, and then 0.2-0.6 parts of triethylamine are added as a catalyst. The reaction mixture is cooled to 0-10°C in an ice bath and stirred for 1-3 hours, then slowly heated to room temperature and stirred for 20-30 hours. After the reaction is completed, the product is extracted with water, the organic layer is dried with anhydrous sodium sulfate, and the tetrahydrofuran is evaporated to obtain an etching enhancer.

5. The method for continuously etching a PTFE tube according to claim 1, characterized in that: The temperature of the etching solution is controlled between 60°C and 70°C.

6. A method for continuously etching a PTFE tube according to claim 1, characterized in that: The PTFE tube stays in the etching solution for 1 to 3 minutes, and the PTFE tube conveyor belt speed ranges from 10 to 50 cm / min.

7. The method for continuously etching a PTFE tube according to claim 1, characterized in that: The rinsing water flow rate is controlled at 2 to 4 L / min, the rinsing water temperature is controlled between 25° C. and 35° C., and the rinsing time is 2 to 5 minutes.

8. The method for continuously etching a PTFE tube according to claim 1, characterized in that: The drying temperature is controlled between 90° C. and 110° C., the wind speed of the hot air nozzle is controlled between 5 and 15 m / s, and the distance between the nozzle and the PTFE tube is 10 to 20 cm.

Images