OZONE APPLICATOR AND METHOD FOR POLYMER OXIDATION
20170072432 ยท 2017-03-16
Inventors
- Suzanne E. Schaefer (Appleton, WI, US)
- Jeremy Lee Winsor (Appleton, WI, US)
- Paul V. Zeyn (Joplin, MO, US)
Cpc classification
C07D417/12
CHEMISTRY; METALLURGY
International classification
B05D3/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Apparatuses and methods are described for distributing gas which may be applicable in the field of polymer oxidation and melt curtain ozonation in particular. Ozone applicators and other features of ozonation apparatuses, which may be used separately or in combination, are also described.
Claims
1. An ozone applicator comprising an elongated inner shell disposed within an elongated outer shell, wherein said inner shell surrounds an interior space, for receiving an inlet stream of ozone-containing gas, and said inner shell has at least one opening for flowing the gas from said interior space into an intermediate space formed between said inner shell and said outer shell, and said outer shell has an outlet in the form of a plurality of openings for discharging the gas from said applicator.
2. The applicator of claim 1, wherein said outer shell has a plurality of openings that are holes distributed along at least a portion of the length of said outer shell.
3. The applicator of claim 1, wherein said at least one opening of said inner shell is in the form of one or more elongated apertures extending along a portion of the length of said inner shell.
4. The applicator of claim 3, wherein said at least one opening of said inner shell is in the form of a single elongated aperture extending over the midpoint of said inner shell.
5. The applicator of claim 1, wherein said at least one opening of said inner shell does not align with said plurality of openings of said outer shell.
6. The applicator of claim 5, wherein said at least one opening of said inner shell is aligned substantially opposite said plurality of openings of said outer shell.
7. The applicator of claim 1, having a length of at least about 24 inches.
8. An ozone applicator comprising an elongated inner shell disposed within an elongated outer shell, wherein said inner shell surrounds an interior space, for receiving an inlet stream of ozone-containing gas, and said inner shell has at least one opening for flowing the gas from said interior space into an intermediate space formed between said inner shell and said outer shell, and said outer shell has at least one outlet for discharging the gas from said applicator.
9. The applicator of claim 8, wherein said inner shell has a plurality of openings.
10. The applicator of claim 9, wherein said plurality of openings are holes distributed along at least a portion of the length of said inner shell.
11. The applicator of claim 8, wherein said outlet of said outer shell is in the form of a slot extending along at least a portion of the length of said outer shell.
12. The applicator of claim 8, wherein said at least one opening of said inner shell does not align with said at least one outlet of said outer shell.
13. The applicator of claim 12, wherein said at least one opening is aligned substantially opposite said at least one outlet.
14. The applicator of claim 8, having a length of at least about 24 inches.
15. An ozone applicator comprising a single elongated shell surrounding an interior space for receiving an inlet stream of ozone-containing gas, wherein said shell has a plurality of openings disposed about part of its surface, within an acute arc of a cross-sectional shape of said shell.
16. The applicator of claim 15, wherein said plurality of openings are holes disposed along at least a portion of the length of said shell.
17. The applicator of claim 15, wherein said holes are disposed along a portion that is centered with respect to the length of said shell.
18. The applicator of claim 15, wherein said holes are disposed in separate, longitudinally extending lines about said surface in a staggered conformation.
19. A method of oxidizing a polymer to improve its adhesion to a substrate, the method comprising exposing a surface of the polymer to an ozone-containing gas discharged from the applicator of claim 1.
20. The method of claim 19, wherein the surface is essentially flat and is formed as a molten extrudate.
21.-31. (canceled)
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
[0032] The features of the apparatuses referred to in
DETAILED DESCRIPTION OF THE INVENTION
[0033] As used herein, for convenience, ozone refers to the triatomic oxygen molecule O.sub.3, while ozone gas refers to gas generated in an ozone generator, having a substantially elevated ozone content relative to the ambient surroundings. Typically this ozone content is in the range from about 10 g/Nm.sup.3 (grams per normal cubic meter) to about 1000 g/Nm.sup.3. Ozone-containing gas refers to a mixture that results when ozone gas is mixed with a diluent gas such as air. The ozone-containing gas therefore has a lower ozone content than the ozone gas prior to mixing, typically in the range from about 2 g/Nm.sup.3 to about 500 g/Nm.sup.3. Diluent gas refers to gas that is essentially free of ozone, for example, containing less than about 5 ppm of ozone. Air is a diluent gas, as are inert gases such as nitrogen and argon. Other types of diluent gases include mixtures of air and inert gases (e.g., nitrogen-enriched air), oxygen, or oxygen-enriched air.
[0034] A representative ozone applicator 10 is depicted in
[0035] Inner and outer shells 14, 12 may be aligned, for example using set screws 25 that are spaced apart around end cap 26.
[0036] A representative cross-section of applicator 10 is shown in
[0037] As shown in the cross-sectional view of
[0038] In a representative embodiment, holes 22 may extend substantially linearly and be spaced apart evenly (e.g., with centers of adjacent holes being spaced apart at an interval that can range from about 3 mm to about 6 mm (about inches to about inches)) along a portion or section of inner shell 14 that is centered with respect to the overall length of inner shell 14. The length of this portion or section may be, for example, from about 30% to about 80%, and often from about 50% to about 70%, of the length of the inner shell. According to an exemplary embodiment where the total length of the applicator (meaning the extended length if the applicator is extendible) is about 140 centimeters (about 55 inches), the length of the section having holes may be about 84 centimeters (about 33 inches). Representative hole diameters are from about 0.8 mm to about 6 mm (about 1/32 inches to about inches), with 1.5 mm to 3 mm ( 1/16 inch to inch) diameter holes being typical.
[0039]
[0040] As with holes 22, described above, slot 24 may extend substantially linearly along a portion or section, in this case of outer shell 12, that is centered with respect to the overall length of outer shell 12. The length of this portion or section may be, for example, from about 30% to about 80%, and often from about 50% to about 70%, of the length of outer shell 12. According to an exemplary embodiment where the total length of the applicator (meaning the extended length if the applicator is extendible) is about 55 inches, the length of the slot is about 33 inches. Representative slot widths are from about 0.8 mm to about 6 mm ( 1/32 inches to about inches), with 1.5 mm ( 1/16 inches) being typical. Alternatively, slot 24 may extend non-linearly, such as in a helical or wave form on the surface of outer shell 12. The slot width may be adjusted, for example, using one or more adjustment screws 16 positioned on outer shell 12 that regulate the amount of force acting to close slot 24 (e.g., by tensioning a clamshell type closure). Other suitable hardware may be used for adjusting the width of slot 24, thereby providing an independent mechanism for controlling the linear velocity of gas exiting slot 24 of applicator 10 (i.e., with a smaller opening directionally increasing gas linear velocity for a given volumetric flow rate). In the case of melt curtain ozonation, fine adjustments to the flow rate of ozone-containing gas, by changing the width of slot 24, may be employed to obtain uniform gas distribution without disruption of the nearby melt curtain (or even to optimize this tradeoff).
[0041] As discussed above, the distribution of gas such as ozone-containing gas from slot 24 of applicator 10 is highly uniform, even in the case of applicator lengths exceeding about 24 inches. Exceptional distribution characteristics have been found to result when any of the applicators described herein having inner and outer shells is configured so that gas pressurized from interior space 20 is forced in different directions through opening 22 and outlet 24 before being discharged. That is, the gas flow direction through opening 22 does not coincide with that through outlet 24, and often these flows are in different directions. It may be desired to configure applicator 10 such that the flows through opening 22 and outlet 24 are in opposite directions. For example, as shown
[0042]
[0043] The central location of elongated aperture(s) provides a good distribution of gas exiting into the intermediate space and then discharging through the outlet of outer shell 12, for example the plurality of holes shown in
[0044]
[0045]
[0046] As is shown in the particular embodiment of
[0047] In the embodiment shown in
[0048] Applicator bars described herein are suitable in polymer oxidation methods to improve the adhesion of a polymer to a substrate. According to such methods, a surface of the polymer (e.g., an essentially flat molten polymer extrudate) may be exposed to an ozone-containing gas discharged from any of the various applicators described above.
[0049] According to the particular polymer oxidation method known as melt curtain ozonation, ozone-containing gas, formed as a mixture of ozone gas and a diluent gas such as air, is routed to an ozone applicator such as those described above. The ozone gas is first formed, at concentrations discussed above, in an ozone generator according to known methods. Aspects of the invention are directed to methods and associated equipment for ensuring that a gas such as a diluent gas flows through the applicator continually during the ozonation process, even when ozone gas flow is stopped or interrupted. For example, ozone gas flow may be diverted from applicator during startup, shutdown, and non-normal operating periods over the course of the ozonation process, such as those associated with operational upsets and/or unsafe conditions. Apparatuses and methods associated with these aspects therefore ensure that gas flows through applicator 10 during ozonation even in the absence of ozone gas flow.
[0050] Accordingly, a representative flow configuration used in equipment such as in an ozonation apparatus for flowing gases to an ozone applicator is depicted in
[0051] In the flow configuration depicted in
[0052] Typical flow rates of ozone gas and diluent gas during normal operating periods range from 2.8 to 280 liters per minute (0.1 to 10 cubic feet per minute (CFM)), but vary significantly according to the particular application. Ratios of ozone gas: diluent gas flow rates often range from 1:10 to 10:1. Ozone applicators described above, which may have an inner shell disposed within an outer shell, or otherwise a single shell with a particular outlet opening configuration, improve gas distribution compared to conventional applicators, allowing for greater flexibility in processes involving gas distribution such as melt curtain ozonation.
[0053] For example, the use of these ozone applicators allows comparatively higher gas flows through the applicator, without resulting in detrimentally high back pressure in the ozone generator, which typically operates at slightly above atmospheric pressure (e.g., from about 0.2 barg to about 0.7 barg (about 3 to about 10 psig)). In one representative embodiment, a flow of 57 liters per minute (2 CFM) of ozone-containing gas through a conventional applicator may result in excessive ozone generator pressures, whereas a flow of 85-113 liters per minute (3-4 CFM) is possible through applicators described above, without exceeding the ozone generator pressure thresholds. According to various embodiments of the invention, a pressure regulator (e.g., a pressure relief valve) may be included in an ozonation apparatus to prevent excessive ozone generator pressures.
[0054] Additionally, ozone applicators described above provide improved gas distribution, for example across the width of a sheet of molten polymer, allowing for comparatively less air or other diluent to be charged to the applicator to achieve a desired degree of distribution (e.g., uniformity of oxidation of a molten polymer surface). Reduced diluent flow rates provide correspondingly increased ozone concentrations in ozone-containing gas discharged from the applicator and consequently improved oxidization of a polymer surface. Overall, therefore, a comparatively greater range of flow rates can be applied to applicators having (i) an inner and outer shell configuration with internal openings (e.g., elongated apertures or otherwise holes) and an outlet (e.g., in the form of a plurality of holes or otherwise an elongated slot), or otherwise (ii) a single shell configuration with a plurality of outlet openings as described above. Gas distribution is improved at low flow rates, while back pressure buildup is managed at high flow rates.
[0055] Ozone applicators as described herein thus provide a number of possible advantages, particularly in melt curtain ozonation processes, such as higher laminate production rates and improved product quality in terms of reduced delamination or greater force needed to separate the polymer from the substrate (e.g., paper) in the finished product. In view of the above, it will be seen that other advantages may be achieved and other advantageous results may be obtained. It will also be appreciated that the apparatuses and methods described above may be used with, or performed in conjunction with, conventional apparatuses and methods, such as those used for corona pre-treatment or flame pretreatment. As various changes could be made in the above apparatuses and methods without departing from the scope of the present disclosure, it is intended that all matter contained in this application shall be interpreted as illustrative only and not limiting in any way the scope of the appended claims.
[0056] The following examples are set forth as representative of the present invention. These examples are not to be construed as limiting the scope of the invention as these and other equivalent embodiments will be apparent in view of the present disclosure and appended claims.
EXAMPLES
[0057] Various melt curtain ozonation studies were undertaken to compare the performance of an ozone applicator as described above and a conventional applicator. Overall testing conditions are summarized in Table 1 and specific operating parameters that were varied in each test are summarized in Tables 2A-2H.
TABLE-US-00001 TABLE 1 1 Roll 1 Roll Ozone Applicator Bars (2) 32,000 ft 60,000 ft 4 -12 P
48
24CT PET 25
wide
Makeready Materials Needed: Mica A131X Primer, NA-204 or NA-214 XL LINE SET-UP Die gap = .030 Nip Impression-
CAAAC Plug or other as only one XL
needed
Temp-
F Die Temp at 500 F. and 610 F. on edges
as specified
indicates data missing or illegible when filed
TABLE-US-00002 TABLE 2A Phase 1-Ozone Value Displayed v/s Voltage and Added Air Use Makeready Film (No Primer) for Phase 1 Part 1: Ozone Monitor in Normal (Current) Position (after added air B4 Applicator Bar) Use current Applicator Bar LDPE at Minimum coating weight and minimum nespeed Record Displayed Value Variable % Voltage Added Air Ozone (g/Nm3) 1 60 0 2 70 0 3 75 0 4 80 0 5 85 0 6 90 0 7 95 0 8 100 0 9 60 1 10 70 1 11 75 1 12 80 1 13 85 1 14 90 1 15 95 1 16 100 1 17 60 2 18 70 2 19 75 2 20 80 2 21 85 2 22 90 2 23 95 2 24 100 Record Ozone Value Variable % Voltage Added Air Displayed 25 60 3 26 70 3 27 75 3 28 80 3 29 85 3 30 90 3 31 95 3 32 100 3
indicates data missing or illegible when filed
TABLE-US-00003 TABLE 2B Part 2: Ozone Monitor Input at OP Side of Applicator Bar LDPE at Minimum coating weight and minimum linespeed Record Displayed Value Variable % Voltage Added Air Ozone (g/Nm3) 40 60 0 41 70 0 42 75 0 43 80 0 44 85 0 45 90 0 46 95 0 47 100 0 48 60 0 49 70 0 50 75 1 51 80 1 52 85 1 53 90 1 54 95 1 55 100 1 56 60 2 57 70 2 58 75 2 59 80 2 60 85 2 61 90 2 62 95 2 63 100 2 Record Ozone Value Variable % Voltage Added Air Displayed 64 60 3 65 70 3 66 75 3 67 80 3 68 85 3 69 90 3 70 95 3 71 100 3
TABLE-US-00004 TABLE 2C Part 3: Ozone Monitor Input at OP Side of Conventional Applicator Bar LDPE at Minimum coating weight and minimum linespeed Record Displayed Value Variable %Voltage Added Air Ozone (g ) 80 60 0 81 70 0 82 75 0 83 80 0 84 85 0 85 90 0 86 95 0 87 100 0 88 60 1 89 70 1 90 75 1 91 80 1 92 85 1 93 90 1 94 95 1 95 100 1 96 60 2 97 70 2 98 75 2 99 80 2 100 85 2 101 90 2 102 95 2 103 100 2 Record Ozone Value Variable % Voltage Added Air Displayed 104 60 3 105 70 3 106 75 3 107 80 3 108 85 3 109 90 3 110 95 3 111 100 3
indicates data missing or illegible when filed
TABLE-US-00005 TABLE 2D Part 4: Ozone Monitor Input at OP Side of Applicator Bar Design Slot Gap at .010 edges, .007 center LDPE at Minimum coating weight and minimum linespeed Record Displayed Value Variable %Voltage Added Air Ozone (g/Nm3) 120 60 0 121 70 0 122 75 0 123 80 0 124 85 0 125 90 0 126 95 0 127 100 0 128 60 1 129 70 1 130 75 1 131 80 1 132 85 1 133 90 1 134 95 1 135 100 1 136 60 2 137 70 2 138 75 2 139 80 2 140 85 2 141 90 2 142 95 2 143 100 2 Record Ozone Value Variable % Voltage Adde dAir Displayed 144 60 3 145 70 3 146 75 3 147 80 3 148 85 3 149 90 3 150 95 3 151 100 3
TABLE-US-00006 TABLE 2E Part 5: Ozone Monitor input at OP Feed with Applicator Bar (Dual Feed) Slot Gap at .010 edge, .007 center LDPE at Minimum coating weight and minimum linespeed Record Displayed Value Variable % Voltage Added Air Ozone (g/Nm3) 160 60 0 161 70 0 162 75 0 163 80 0 164 85 0 165 90 0 166 95 0 167 100 0 169 60 1 169 70 1 170 75 1 171 80 1 172 85 1 173 90 1 174 95 1 175 100 1 176 60 2 177 70 2 178 75 2 179 80 2 180 85 2 181 90 2 182 95 2 183 100 2 Record Ozone Value Variable % Voltage Added Air Displayed 184 60 3 185 70 3 186 75 3 187 80 3 188 85 3 189 90 3 190 95 3 191 100 3
TABLE-US-00007 TABLE 2F Phase 2-Ozone/TIAG Adhesion Phase 2 Structure-48 ga PET/PEI/15# LDPE (NA-214) Insert Slip Sheet labeled with Variable Number. NA214 Melt Temp-590 F. Save Sample labeled with OP Side for Aged Adhesion Testing. Die Temp at 590 F. and 595 F. on edges Ozone at 35 psi, O2 = 80 , Added Air = 2
, Reactor Pressure = 4.5 Part 1: Ozone Monitor Input at OP Side of Conventional Applicator Bar Record Off-line Aged Variable Linespeed Airgap Ozone Monitor (g/Nm3) Voltage (%) TIAG Adhesion Adhesion 200 400 9 0 100 201 400 8.2 0 90 202 400 7.4 0 80 203 435 7.1 0 70 204 510 7.1 0 60 205 605 7.1 0 50 206 760 7.1 0 40 207 400 9 70 100 208 400 8.2 70 90 209 400 7.4 70 80 210 435 7.1 70 70 211 510 7.1 70 60 212 605 7.1 70 50 213 760 7.1 70 40 214 400 9 80 100 215 400 8.2 80 90 216 400 7.4 80 80 217 435 7.1 80 70 218 510 7.1 80 60 219 605 7.1 80 50 220 760 7.1 80 40 221 400 9 90 100 222 400 8.2 90 90 223 400 7.4 90 80 224 435 7.1 90 70 225 510 7.1 90 60 226 605 7.1 90 50 227 760 7.1 90 40 228 1010 7.1 90 30
indicates data missing or illegible when filed
TABLE-US-00008 TABLE 2G Part 2: Ozone Monitor Input at OP Feed with Applicator Bar (Dual Feed) Slot Gap at .010 edge, .007 center Record Ozone Line- Monitor Voltage Off-line Aged Variable speed Airgap (g/Nm3) (%) TIAG Adhesion Adhesion 229 400 9 70 100 230 400 8.2 70 90 231 400 7.4 70 80 232 435 7.1 70 70 233 510 7.1 70 60 234 605 7.1 70 50 235 760 7.1 70 40 236 400 9 80 100 237 400 8.2 80 90 238 400 7.4 80 80 239 435 7.1 80 70 240 510 7.1 80 60 241 605 7.1 80 50 242 760 7.1 80 40 243 400 9 90 100 244 400 8.2 90 90 245 400 7.4 90 80 246 435 7.1 90 70 247 510 7.1 90 60 248 605 7.1 90 50 249 760 7.1 90 40 250 1010 7.1 90 30
TABLE-US-00009 TABLE 2H Part 3: Coating Weight/Minimum Ozone versus Adhesion Ozone Monitor input at OP Feed with Applicator Bar (Dual Feed) Slot Gap at .010 edge, .007 center Record Ozone Monitor Voltage Coating Off-line Aged Variable Linespeed Airgap (g/Nm3) (%) Weight TIAG Adhesion Adhesion 301 510 7.1 0 10 60 302 510 7.1 70 10 60 303 605 7.1 70 10 50 304 760 7.1 70 10 40 305 510 7.1 80 10 60 306 605 7.1 80 10 50 307 760 7.1 80 10 40 308 1010 7.1 80 10 30 309 1010 7.1 80 15 30 310 1010 7.1 80 10 30