Methods and equipment for manufacturing plastic hoses, and plastic hoses

Abstract

The present invention relates to a method for manufacturing an extruded hose, wherein the hose is formed of a plastic material that is extruded from a mold in a liquid or paste form, wherein the raw material is fed into an extruder and liquefied and compressed and degassed if necessary, wherein the raw material and / or the hose are flushed with a fluid before and / or after extrusion.

Description

Technical Field

[0001] This invention relates to a method and apparatus for manufacturing plastic hoses, and specifically to a plastic hose. Prior Technology

[0002] Such hoses are used, for example, to transport fluids in semiconductor technology.

[0003] Hose made of plastic materials is typically manufactured using an extrusion process. Here, raw materials, usually solid, are guided through an extruder, liquefied, and compressed, then pressed through a die and cooled in a cooling tank.

[0004] This method is known from U.S. Patent Nos. 3,826,122 and 6,526,859 B1.

[0005] A method for manufacturing hose blanks is known from DE 695 30 876 T2, wherein a semi-finished hose blank is manufactured, which can then be further processed, such as lengthening or stretching. Manufacturing is carried out using an extrusion apparatus comprising an extruder and a nozzle body. PTFA paste is fed into the extrusion apparatus, preformed into a strip, and introduced into the extruder. The tubular PTFA strip guided through the extruder is then guided to the nozzle body. The resulting tubular extrudate exits the extrusion apparatus and is then cut to arbitrary lengths. During the manufacturing process, the extrusion apparatus and the hose blanks thereby produced are maintained at a constant temperature.

[0006] It is known that temperature conditions can be variably controlled in this extrusion process according to the melt temperature of the polymer feedstock used. An extrusion process is known from US 2013 / 0000767 A1, in which the hose to be manufactured is molded in an extruder, vulcanized at an elevated temperature, and then cooled with a cold fluid.

[0007] A drawback of the known manufacturing methods is that various contaminants, particularly those of organic origin, are introduced into the hose material during the manufacturing process. If hoses contaminated in this way are installed in a facility, these contaminants, or their volatile and non-volatile components, may be released into the facility. This process is called venting.

[0008] The presence of the above-mentioned pollutants is called "TOC" (Total Organic Pollutants), and is characterized by the so-called TOC value.

[0009] The released TOC pollutants can hinder the operation of facilities, thereby greatly reducing the efficiency of the facilities.

[0010] It is known that the manufactured hose is exposed to a cold or hot airflow to minimize subsequent exhaust. However, this method is not suitable for adequately removing TOC contaminants. Furthermore, this process is time-consuming and expensive.

[0011] It has been found that conventional hoses can arbitrarily exceed or fall below the TOC (Total Organic Charge) threshold without being able to make predictions. This results in a certain level of cost because the actual values ​​must be determined, and the hose may only be classified as unsuitable in the hands of the user. Summary of the Invention

[0012] The purpose of this invention is to provide a method for manufacturing plastic hoses, by which the TOC limit value can be predictably and reliably ensured.

[0013] This objective is achieved by a method that has the characteristics of request item 1.

[0014] Further favorable developments are indicated in the appendices attached to claim 1.

[0015] Another object of the present invention is to provide an apparatus for manufacturing plastic hoses, which can be used to manufacture hoses that meet TOC limit values.

[0016] Further favorable developments are indicated in the relevant appendices.

[0017] This objective is achieved by means of a device having the features of request item 12.

[0018] Another object of the present invention is to provide a corresponding hose that conforms to the TOC limit value.

[0019] This objective is achieved by a hose having the features of claim 16.

[0020] It has been recognized that hoses manufactured in conventional ways often have excessively high TOC contamination. TOC fluctuations are unpredictable, and high contamination is usually only identified during application, leading to the disposal of highly contaminated hoses. Furthermore, high TOC contamination causes contamination of related facilities. To prevent this, the inventors have recognized the necessity of thorough pre-cleaning of hoses, particularly through a multi-stage cleaning process.

[0021] This invention provides a further development that controls TOC contaminants at each manufacturing step to eliminate potential TOC contaminants in each step. For this purpose, the purest and most contaminant-free raw materials are used. These raw materials undergo an extrusion process and a cleaning process at each manufacturing step.

[0022] Compounds that can be used as precursors for thermoplastic plastics are suitable as raw materials.

[0023] Thermoplastics are plastics that can deform or liquefy within a certain temperature range. This process is reversible and can be repeated with any frequency of cooling and reheating. When the so-called decomposition temperature associated with the material is reached, the material irreversibly degrades.

[0024] The most commonly used thermoplastics are polyolefins, such as polyethylene and polypropylene. Other thermoplastics also used industrially include acrylonitrile-butadiene-styrene (ABS), polyamide (PA), polylactic acid (PLA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polystyrene (PS), polyetheretherketone (PEEK), and polyvinyl chloride (PVC).

[0025] According to the present invention, raw materials (usually in granular form) preferably packaged under cleanroom conditions are supplied to the extrusion equipment.

[0026] A cleanroom is a space where the concentration of airborne particles is kept very low. Packaging under cleanroom conditions helps to eliminate potential contamination in advance. Raw materials to be used can be packaged under cleanroom conditions in special packaging materials that are preferably suitable for cleanroom applications. To maintain the lowest possible level of contamination, raw materials can be packaged multiple times, such as two or three times.

[0027] In the extrusion equipment, the material undergoes at least one cleaning step. A fluid can be used as the cleaning medium. Preferably, several cleaning stages can be incorporated.

[0028] The suitable fluid can be either gaseous or liquid.

[0029] Particularly suitable fluids include XCDA (extremely clean dry air), XCHA (extremely clean humid air), or UPW (ultrapure water). The fluid can be cold or warm.

[0030] Therefore, the present invention relates in particular to a method for manufacturing an extruded hose, wherein the hose is formed of a plastic material that is extruded from a mold in liquid or paste form, wherein the raw material is fed into an extruder and liquefied and compressed and degassed if necessary, characterized in that the raw material and / or the hose are flushed with a fluid before and / or after extrusion.

[0031] Another advantageous embodiment is configured such that the raw material is rinsed with the fluid before being fed into the extruder.

[0032] In yet another advantageous embodiment, the hose is flushed from the inside and / or outside with the fluid as it exits the mold.

[0033] The following is advantageous: the area of ​​the molten pool is surrounded by an outer casing to shield it from external contamination.

[0034] Preferably, the hose is also flushed from the inside and / or outside with the fluid in a cooling bath.

[0035] In another embodiment, the raw material and / or the hose are flushed with a gaseous fluid.

[0036] The following are also advantageous: the flow system contains either extremely dry or humid gases.

[0037] Another advantageous embodiment is configured such that the fluid is air, nitrogen, carbon dioxide, water vapor, a reactive gas such as ozone, an inert gas, or a mixture of the above gases.

[0038] The fluid is preferably a liquid, especially pure water and / or distilled water or another liquid solvent.

[0039] The following is also advantageous: using a mold that includes a fluid supply device, so that the fluid can be flushed into the extruded hose from within.

[0040] Preferably, the fluid is guided to flow through the material in the opposite direction to the direction of material supply.

[0041] Another advantageous embodiment is configured such that the fluid is drawn out after passing through the raw material or the hose.

[0042] The present invention also relates to an apparatus for performing the above-described method, wherein the apparatus is an extrusion apparatus, the extrusion apparatus including a raw material supply device having a supply port, wherein the supply device is connected to a first cleaning device, wherein the lower end of the first cleaning device is connected to an extruder inlet, wherein the extruder inlet is disposed on an extruder, the extruder including a screw and an extruder outlet, wherein a die is disposed on the extruder outlet, the die including a fluid supply device.

[0043] One advantageous embodiment is configured such that the molten pool with a second cleaning device is positioned after the mold.

[0044] In yet another advantageous embodiment, a cooling pool with a third cleaning device is disposed after the molten pool. Simple Explanation of the Diagram

[0045] The invention will be illustrated by way of example with reference to the accompanying drawings. In the drawings:

[0046] Figure 1 illustrates an extrusion apparatus according to the present invention;

[0047] Figure 2 illustrates a conventional extrusion apparatus. Implementation

[0048] As is well known, the conventional extrusion apparatus 101 (Figure 2) includes a feeding device 102 having a feeding port 103. The lower end of the feeding device 101 is connected to an extruder. The extruder includes a screw 104 and an extruder outlet 105. A die 106 is arranged on the extruder outlet 105. A cooling pool 107 and an outlet 108 are arranged after the die 106.

[0049] The raw material is introduced through the feed port 103 and enters the extruder via the feed device 102. The raw material is liquefied and compressed in the extruder and then pressed by the die 106. This produces a hose 109, which is led to a cooling tank 107. Cooling of the hose 109 takes place in the cooling tank 107. The final product is removed from the outlet 108. Cleaning is typically performed at the end of the manufacturing process by rinsing the finished product with air.

[0050] The extrusion apparatus 1 (Figure 1) according to the present invention includes a raw material supply device 2 having a supply port 3. A first cleaning device 4 is disposed at the lower end of the supply device 2. The first cleaning device 4 may be formed in a tubular shape. The first cleaning device 4 includes a first fluid inlet 5 and a first fluid outlet 6. The first fluid inlet 5 is disposed at the lower end of the first cleaning device 4, and the first fluid outlet 6 is disposed at the upper end of the first cleaning device 4. The lower end of the first cleaning device 4 is connected to an extruder inlet 7. The extruder inlet 7 is part of an extruder 8, which also includes a screw 9 and an extruder outlet 10. The screw 9 is axially disposed inside the extruder 8. A die 11 is attached to the extruder outlet 10. The die 11 includes a second fluid inlet 12. A melt pool 13 is located after the die 11. A second cleaning device 14 is disposed in the region of the melt pool 13. The region of the melt pool 13 is surrounded by an outer casing 13a. A cooling pool 15 is disposed after the melt pool 13. The cooling pool 15 includes a third cleaning device 16.

[0051] The extrusion equipment 1 can also be located in a cleanroom, thereby protecting the blank or the outside of the hose 17 from possible external contamination after manufacturing. Furthermore, the manufactured hose 17 can then be packaged under cleanroom conditions.

[0052] Preferredly, under cleanroom conditions, the raw material, which has been packaged several times, is introduced into the extrusion apparatus 1 through the supply port 3 of the supply device 2. The raw material then enters the first cleaning device 4 via the supply device 2, where it is cleaned with a cleaning medium. This cleaning medium can be, for example, a cold or hot XCDA fluid or XCHA fluid. Cleaning is performed as follows: the corresponding fluid is introduced through the first fluid inlet 5 at the lower end of the first cleaning device 4 and flows against the direction of raw material feed. Contaminants contained in the raw material are absorbed by the cleaning medium and flushed away through the first fluid outlet 6 located at the upper end of the cleaning device 4.

[0053] The pre-cleaned material is further introduced into the extruder inlet 7 and reaches the extruder 8. In the extruder 8, the material is liquefied and compressed in a conventional manner, and degassed if necessary. The liquefied material exits the extruder 8 through the extruder outlet 10 and is pressed by the die 11 to form a hose 17. Here, a cleaning medium (particularly XCDA or XCHA) is introduced into the hose through the die 11 via the second fluid inlet 12. Contaminants (particularly TOC contaminants) are absorbed by the cleaning medium and discharged at the end of the hose. This cleans the interior of the hose 17.

[0054] Next, the hose emerges from the extruder nozzle in a molten fluid state. This area is referred to as the molten pool 13. Thereafter, the outside of the hose 17 is cleaned in a third cleaning step. This third cleaning step takes place in the molten pool 13, where a cleaning medium (a fluid, particularly XCDA) is introduced through a second cleaning device 14. Here, the hot, still relatively low-viscosity hose 17 is flushed from the outside by the cleaning medium. In this way, contaminants, particularly TOC contaminants, are removed from the outside of the hose 17.

[0055] In the region of the molten pool 13, the outer cover 13a or outer shell 13a is advantageously arranged such that when the hose exits the extruder nozzle, it does not come into contact with the outside atmosphere, but is preferably shielded until it is guided to the cooling pool. Thus, the outer cover 13a surrounding the molten pool region shields the hose 17, which remains in a liquid state, so that no contaminants can enter the melt from the outside.

[0056] The outer cover 13a can be formed in the shape of a tube or a cylinder. The outer cover 13a is made of solid and can have transparent areas.

[0057] Therefore, the cleaning process is also carried out in an effective manner within the enclosure, i.e., within an enclosed space; for this purpose, the supply and discharge of the cleaning fluid are advantageously provided.

[0058] This allows for simultaneous cleaning of both the interior and exterior, especially in high-temperature areas where TOC pollutants are particularly volatile.

[0059] The fourth cleaning step is carried out in the cooling tank 15. A cleaning medium (particularly UPW) is introduced through the third cleaning device 16, and further contaminants are removed. This ensures particularly reliable and effective cleaning.

[0060] The advantage of this invention is that, if necessary, contaminants, especially TOC contaminants, can be reliably removed in several cleaning steps.

[0061] In the first cleaning step, the raw materials are pre-cleaned to reduce TOC contamination in advance.

[0062] It is also advantageous to use raw materials with particularly high purity.

[0063] In the second cleaning step, the hose 17 is cleaned from the inside with fluid, and in the third cleaning step, the hose 17 is cleaned from the outside with fluid. These steps are performed almost simultaneously. In addition, the hose 17, which is still of low viscosity, is protected from possible external contamination in the area of ​​the molten pool 13 by an outer cover 13a.

[0064] Advantageously, in the fourth cleaning step performed in the cooling bath 15, the remaining contaminants are removed to the greatest extent possible with fluid.

[0065] Another advantage is that it can reduce or even prevent the effects of exhaust gases.

[0066] According to the invention, it is advantageous that the hoses can be manufactured with very high purity, so that no additional cleaning is required before use (e.g., in the facility).

[0067] The above description of the cleaning method according to the invention is based on an extrusion method. It will be apparent to those skilled in the art that the invention can be used successfully without relying on a molding process, since the invention's understanding of maintaining cleanliness and the cleaned parts and intermediate products is naturally independent of the molding process. In this regard, extrusion represents all suitable molding processes, such as blow molding, compression molding, injection molding, and combinations thereof. However, this enumeration should not be construed as exhaustive.

[0068] 1: Extrusion equipment 2: Raw material supply device 3: Supply Port 4: First cleaning device 5: First fluid inlet 6: First fluid outlet 7: Extruder Inlet 8: Extruder 9: Screw 10: Extruder outlet 11: Mold 12: Second fluid inlet 13: Molten Pool 13a: Outer casing / shell 14: Second cleaning device 15: Cooling pool 16: Third Cleaning Device 17: Hose 101: Extrusion Equipment 102: Supply device 103: Supply Port 104: Screw 105: Extruder outlet 106: Mold 107: Cooling pool 108: Exports 109: Hose

[0069] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A method for manufacturing a plastic hose (17), wherein the hose (17) is formed of a plastic material that is extruded from a mold (11) in liquid or paste form, wherein a raw material is supplied to an extruder (8) and liquefied and compressed therein, characterized in that: the raw material is rinsed with a fluid as a cleaning medium before extrusion and / or the hose (17) is rinsed with a fluid as a cleaning medium after extrusion to remove total organic contaminants, wherein the hot and low-viscosity hose (17) is immediately rinsed from the outside with the fluid in a molten pool (13) after extrusion.

2. The method as described in claim 1, wherein the raw material is degassed in the extruder (8).

3. The method as described in claim 1, wherein the raw material is flushed with the fluid before being fed into the extruder (8).

4. The method as described in claim 1, wherein the hose (17) is flushed from the inside and / or outside with the fluid as it exits the mold (11).

5. The method as described in claim 1, wherein the hose (17) is further flushed from the inside and / or outside with the fluid in a cooling pool (15).

6. The method as described in claim 1, wherein the raw material and / or the hose (17) are flushed with a gaseous fluid.

7. The method as described in claim 1, wherein the fluid system is an extremely dry or humid gas.

8. The method as described in claim 1, wherein the fluid is air, nitrogen, carbon dioxide, water vapor, a reactive gas, an inert gas, or a mixture of the above gases.

9. The method as described in claim 8, wherein the reacting gas is ozone.

10. The method as described in claim 1, wherein the fluid is a liquid.

11. The method as described in claim 10, wherein the fluid is pure water and / or distilled water.

12. The method as described in claim 1, wherein a mold (11) is used, the mold (11) including a fluid supply device (12) such that the fluid can be flushed into the extruded hose (17) from the inside.

13. The method as described in claim 1, wherein the fluid is directed to flow through the material in the opposite direction to the supply direction of the material.

14. The method as described in claim 1, wherein the fluid is drawn out after passing through the raw material or the hose (17).

15. An apparatus for performing the method as described in claim 1, characterized in that: the apparatus is an extrusion apparatus (1) comprising a raw material supply device (2) having a supply port (3), wherein the supply device (2) is connected to a first cleaning device (4) for removing total organic contaminants, wherein the lower end of the first cleaning device (4) is connected to an extruder inlet (7), wherein the extruder inlet (7) is disposed on an extruder (8), the extruder (8) comprising a screw (9) and an extruder outlet (10), wherein a die (11) is disposed on the extruder outlet (10), the die (11) comprising a fluid supply device (12).

16. The apparatus as claimed in claim 15, wherein a molten pool (13) having a second cleaning device (14) is disposed after the mold (11).

17. The apparatus as described in claim 15 or 16, wherein the area of ​​the molten pool (13) is surrounded by an outer casing (13a) to shield against external contamination.

18. The apparatus as claimed in claim 15, wherein a cooling pool (15) having a third cleaning device (16) is disposed after the molten pool (13).

19. A plastic hose (17) manufactured by the method described in any one of claims 1 to 14.

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