ARTICLE AND METHOD FOR MAKING SAME

Abstract

An article includes a layer including a melt proces sable fluoropolymer, wherein the fluoropolymer includes a copolymer of a tetrafluoroethylene and a perfluoroether, wherein the article has an ultraviolet transmittance of at least about 50% at a thickness of about 0.040 inches to about 0.062 inches when exposed to ultraviolet radiation of about 200 nm to about 280 nm. Further provided is a method of making the article and an apparatus for purifying water including an article, such as a flexible tube.

Claims

1. A method of making an article comprises: providing a layer comprising a melt processable fluoropolymer, wherein the fluoropolymer comprises a copolymer of a tetrafluoroethylene and a perfluoroether, wherein the article has an ultraviolet transmittance of at least about 50% when measured at a thickness of about 0.040 inches to about 0.062 inches when exposed to ultraviolet radiation of about 200 nm to about 280 nm.

2. The method of making the article of claim 1, wherein providing the layer comprises extruding the melt proces sable fluoropolymer.

3. The method of making the article of claim 2, further comprising cooling the article at a temperature less than a melting temperature of the fluoropolymer.

4. The method of making the article of claim 3, wherein cooling is at a temperature of about 1° C. to about 99° C.

5. The method of making the article of claim 4, wherein the temperature is about 1° C. to about 25° C.

6. The method of making the article of claim 3, wherein cooling is in water.

7. The method of making the article of claim 1, wherein the melt processable fluoropolymer consists essentially of the copolymer of the tetrafluoroethylene and the perfluoroether.

8. The method of making the article of claim 1, wherein the perfluoroether comprises perfluoropropyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, or combination thereof.

9. The method of making the article of claim 8, wherein the perfluoroether consists essentially of perfluoropropyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, or combination thereof.

10. The method of making the article of claim 1, wherein the copolymer of tetrafluoroethylene and the perfluoroether are present at a weight percent ratio of about 2% to about 12%.

11. The method of making the article of claim 1, wherein the fluoropolymer has optical clarity.

12. The method of making the article of claim 1, wherein the article has an ultraviolet transmittance of at least about 60%.

13. The method of making the article of claim 1, wherein the melt processable fluoropolymer has a crystallinity of at least about 1%.

14. The method of making the article of claim 13, wherein the melt processable fluoropolymer has a crystallinity of about 1% to about 75%.

15. The method of making the article of claim 1, wherein the article has a flexural modulus of at least about 400 MPa.

16. The method of making the article of claim 1, wherein the melt processable fluoropolymer has a tensile yield of about 0.5% to about 15%.

17. The method of making the article of claim 1, wherein the article has a shore D durometer of less than about 90 at a temperature of about 23° C.+/−5° C.

18. The method of making the article of claim 1, wherein the article has a total thickness of about 0.0005 inches to about 0.250 inches.

19. The method of making the article of claim 1, wherein the article has an inner surface providing a conduit for a fluid.

20. The method of making the article of claim 19, wherein the fluid is water.

Description

EXAMPLES

[0061] Several tubes are formed using varying resins and two different processing conditions. The three different resin options 1, 2, and 3 are each a copolymer of a tetrafluoroethylene and a perfluoroalkyl vinyl ether. These tubes are compared to a baseline (Tube 5) of FEP (fluorinated ethylene propylene resin). The FEP is a copolymer of tetrafluoroethylene and hexafluoropropylene or a terpolymer of tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether.

[0062] Two different process conditions were used. The melt processable fluoropolymer is melted and then tubes are extruded and cooled either at a temperature above 70° F. (process A) or below 70° F. (process B).

[0063] The tubing had a wall thickness of 0.045 inches and UV transmission is measured at wavelengths from 200 nm to 295 nm. Results can be seen in Table 1:

TABLE-US-00001 TABLE 1 Baseline TUBE 5 TUBE 6 TUBE 7 TUBE 8 TUBE 9 TUBE 11 TUBE 10 Wavelength Transmission Baseline Option Option Option Option Option Option (nanometer) (%) A 3B 3A 2B 2A 1B 1A 200.00 101.43 21.45 56.89 51.08 56.44 51.87 46.66 47.72 205.00 102.50 20.28 53.78 48.29 53.36 49.03 44.11 45.11 210.00 101.50 21.11 58.84 53.12 58.29 51.04 45.92 46.96 215.00 101.14 25.88 62.99 57.22 61.27 54.75 50.52 51.98 220.00 100.57 30.30 65.32 59.67 64.44 57.92 54.64 56.04 225.00  99.55 34.96 67.33 62.08 66.50 60.34 58.34 59.29 230.00  99.56 39.51 69.35 64.25 68.15 62.44 61.31 61.89 235.00  99.23 43.70 70.41 65.33 69.04 63.91 63.24 64.03 240.00  99.76 47.80 71.31 66.41 69.89 65.17 65.06 65.75 245.00  99.71 51.16 71.84 67.12 70.32 65.71 66.09 66.93 250.00  99.79 53.55 71.58 67.00 70.00 65.80 66.54 67.10 255.00 100.02 55.49 71.31 67.09 70.04 65.62 66.97 67.46 260.00 100.01 57.34 71.55 67.40 70.37 65.85 67.72 68.22 265.00  99.75 59.23 72.27 68.08 70.92 66.60 68.70 69.09 270.00  99.85 60.89 72.89 68.81 71.64 67.26 69.82 70.23 275.00  99.78 62.28 73.56 69.75 72.39 68.00 70.72 71.26 280.00  99.79 63.73 74.37 70.43 73.30 68.86 71.71 72.29 285.00  99.86 64.84 74.85 71.17 73.87 69.45 72.55 72.96 290.00  99.78 65.65 75.27 71.81 74.36 69.95 73.16 73.67 295.00  99.77 66.41 75.76 72.15 74.84 70.41 73.87 74.10

[0064] Clearly, Options 1, 2, and 3 all have improved UV transmission across all wavelength values compared to the baseline tube (FEP). Further, the process using the lower cooling temperature shows an improvement in UV transmission for both Options 1 and 2.

[0065] Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed are not necessarily the order in which they are performed.

[0066] In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

[0067] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

[0068] After reading the specification, skilled artisans will appreciate that certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, references to values stated in ranges include each and every value within that range.