1
A New Protein Reduction System for Latex Glove Manufacturing – Bioblox™
MARGMA International Rubber Glove Conference, 12...
2
The standard method for lowering protein for the targeted product family of
this study (powdered gloves and polymer coat...
3
The washing of articles, regardless of material composition, is a long standing
method of removing contaminants and rest...
4
2. ASTM D3578, which cites targeted maximum
allowable protein levels in powdered gloves of 200
mg/dm2.
In turn, to ensur...
5
Dip Machine: DipTech Systems Diplomat™ Computerized Pilot Plant
Diplomat Pilot Plant Finished Gloves before stripping
Th...
6
Bioblox™ Concentration in Leach Water: 0.5% Active Ingredient finalized after
testing levels at 0.25%, 0.5%, and 1.0% Ac...
7
Testing for Round 4 was established with pre-oven leach residence time as 30
seconds and post leach residence time of 15...
8
25 seconds Bioblox treatment. Pre Oven leach of 30 seconds of Bioblox
treatment only continued.
Round 5 resulted in the ...
9
Many glove lines have 3 or more separate leach tanks for both pre oven and
post oven leaching. Earlier results showed th...
10
Station Leach H20
only
Bioblox™ Leach H20
only
Total Leach
Pre Oven
Leach
10 seconds 15 seconds 10 seconds 35 seconds
P...
11
To further validate protein reduction potential of Bioblox™, samples consistent
with the leaching process in Round 11 (...
12
demonstrated potential to achieve protein reduction better than existing
methods, while conserving energy costs so vita...
13
Figure 1: EXAMPLE OF METERING PUMP FOR BIOBLOX™ (reference:Figure 1: EXAMPLE OF METERING PUMP FOR BIOBLOX™ (reference:F...
14
• Second Stage Leaching – Bioblox™ treatment in water
• Third Stage Leaching – water only (residual rinse)
Residence ti...
15
1. Potential to remove vulcanization residues for both NR latex and nitrile
gloves.
2. Post process laundering benefits...
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Protein reduction system_margma_06

  1. 1. 1 A New Protein Reduction System for Latex Glove Manufacturing – Bioblox™ MARGMA International Rubber Glove Conference, 12 – 14 September 2006 By Rick Tabor, Research Associate; Stepan Company (USA) and Bill Howe, PolyTech Synergies LLC. (USA) IntroduIntroduIntroduIntroductionctionctionction The topic of protein reduction for latex gloves and other articles comprised of NR latex is no stranger to manufacturers of these products. Research continues in efforts to reduce protein levels by double centrifuging, or through additives to the latex concentrate at the plantation level prior to shipment to the manufacturing plant. In all cases known thus far, the cost of NR latex raw material increases commensurately with the cost of the additional processes and/or materials required to demonstrate benefit by these products for manufacturers seeking lower protein levels. In the 1990’s, a slip coating was first introduced to replace powder as a glove donning agent. Today, the growth of powderfree gloves by polymer coating method continues, along with the steady presence of powdered gloves. For these products, manufacturers continue to welcome methods to further reduce protein levels in latex gloves. Post process chlorinated gloves were not targeted for this study, in that most of this product family benefits from significant protein reduction afforded by the exposure to chlorination and downstream post washing.
  2. 2. 2 The standard method for lowering protein for the targeted product family of this study (powdered gloves and polymer coated gloves) is that of longer leaching times and/or higher leaching temperatures, sometimes as high as 70 degrees Celsius. That technique for continues today in many manufacturing plants, and adds cost primarily through energy consumption and water consumption. The intent of this study was to develop an on-line leach tank protein reduction additive that would seamlessly be implemented within most existing glove manufacturing plants for powdered latex gloves and polymer coated latex gloves. The goal is to achieve the following: 1. Result in no compromise to physical properties of the latex film. 2. Be environmentally safe and be compatible with existing post water treatment plants. 3. Add no cost, or even possibly decrease manufacturing cost of the latex article. To achieve this, the modest cost of the additive would need to be offset by reduced leaching times, lower operating temperatures in the leaching system, or other yet unidentified savings. 4. Add little or no cost to manufacturing lines in the way of additional equipment and/or modification to existing lines. 5. Result in impressive reduction of extractable proteins of latex articles, in tandem with objectives one through four above. The PremiseThe PremiseThe PremiseThe Premise
  3. 3. 3 The washing of articles, regardless of material composition, is a long standing method of removing contaminants and restoring articles as close as possible to their original state of cleanliness. To optimize the washing of clothing, for example, one would employ the use of a detergent that contains certain surfactants to assist in removal of stains caused by many outside factors. The stains are effectively loosened and released from the fabric in tandem with detergent washing followed by water rinsing to remove the stains along with any residual cleaning agents. Residential laundry detergents are environmentally safe, of course, posing no hazard to water treatment plants or the community in general. In turn, the objective of this study was to test introduction of certain surfactants into the leaching process for latex gloves that would in turn result in enhance or accelerate removal of extractable proteins in latex films, especially gloves. Unlike detergents used for washing clothes, the combination of ingredients used for latex glove manufacturing applications would need to keep foaming non-existent or kept at least to minimum levels controllable by industry de-foaming aids. Testing Parameters and ProtocolTesting Parameters and ProtocolTesting Parameters and ProtocolTesting Parameters and Protocol Protocol used for testing was: 1. The Standard Malaysian Glove Program, which cites targeted maximum allowable protein levels in powdered gloves of 200 mg/dm2.
  4. 4. 4 2. ASTM D3578, which cites targeted maximum allowable protein levels in powdered gloves of 200 mg/dm2. In turn, to ensure measurable and accurate detection, the “Control” target for subsequent testing was determined to be 200 mg/g or approximately 300 mg/dm2 (Modified Lowry method). Testing was conducted using the following independent laboratories and associated testing regimen: Testing MethodTesting MethodTesting MethodTesting Method Lab / LocationLab / LocationLab / LocationLab / Location ASTM D5712-95 Modified Lowry Leap Testing Service, USA ASTM D6499-03 Inhibition ELISA Leap Testing Service, USA FITkit® Quattromed Ltd., Estonia Product made for Protein Testing Purposes: Examination Glove Latex Used: Pre-vulcanized Thai latex compounded by Killian Latex; Akron, Ohio USA. Coagulant: Water based with 20% calcium nitrate, wetting agents, and release agent. Leach water: Salem, Ohio City Water and de-ionized water by reverse osmosis.
  5. 5. 5 Dip Machine: DipTech Systems Diplomat™ Computerized Pilot Plant Diplomat Pilot Plant Finished Gloves before stripping The initial repeatable glove manufacturing process employed was as follows: 1. Clean Mold with warm water 2. Coag Dip – 1 ips entry / 5 seconds dwell / 2 ips exit 3. Coag Dry – 1 minute with rotation and heated convection 4. Latex Dip – 1 ips entry / dwell 9 seconds / 2 ips exit 5. Air dry 60 seconds 6. Pre Oven Leach – 3 minutes @ 54 degrees C (time and temperature later reduced) 7. Oven Dry – 1 minute at 80 degrees C 8. Bead roll by hand 9. Cure – 13 minutes at 100 degrees C / 2 minutes - 110 degrees C 10. Post leach – 2 minutes @ 54 degrees C (later reduced) 11. Oven Dry – 2 minutes at 70 degrees C. 12. Cool Down – 2 minutes ambient 13. Powder by hand 14. Strip (hand protection – disposable nitrile gloves)
  6. 6. 6 Bioblox™ Concentration in Leach Water: 0.5% Active Ingredient finalized after testing levels at 0.25%, 0.5%, and 1.0% Active Ingredient. Testing HistoryTesting HistoryTesting HistoryTesting History Round one of testing showed that “control” levels of protein in gloves, using the Modified Lowry method were undetectable (less than 28 mg/g or less than 41 mg/dm2). It was determined that the use of Salem, Ohio city water for leaching was introducing bias into the study model. This water had chlorine present through addition at the city water treatment plant. Therefore, subsequent iterations were switched to de-ionized water through reverse osmosis process to remove ingredients influencing the study results. Round two’s testing resulted in similar results of below detectable limits for “control”; this after water temperature was reduced to 38 degrees Celsius for this round of testing. Round three focused on centering in on proper “control” standards against which Bioblox™ treatment would be measured. Leach temperatures were set to 38 degrees C. Results from the laboratory were as follows: Lab Iteration Pre Leach Post Leach Protein mg/g Protein mg/dm2 M 30 seconds 15 seconds 105 169 N 0 seconds 30 seconds 729 1052 O 30 seconds 30 seconds 237 366 P 180 seconds 30 seconds 33 52
  7. 7. 7 Testing for Round 4 was established with pre-oven leach residence time as 30 seconds and post leach residence time of 15 seconds, in accordance with Group M in the previous round (that closest to the SMG standard of 200 mg/dm2). Five different grades of Bioblox™ surfactant treatment were tested against control. For Bioblox™ treatment, both pre-oven leaching and post- oven leaching residence times of 30 seconds and 15 seconds respectively, were subjected to 100% exposure to Bioblox™ additive at 0.5% active ingredient to water. No residual rinse for either step was employed. Results demonstrated that the process established for this round actually increased protein content against “control”. Round 4 ResultsRound 4 ResultsRound 4 ResultsRound 4 Results Group ID Additive Lowry mg/g Lowry mg/dm2 ELISA mg/dm2 Q Control 351 538 9.3 R Bioblox L 546 906 18.9 S Bioblox A 561 879 47.9 T Bioblox S 402 634 13.7 U Bioblox M 534 854 13.7 V Bioblox 460 360 568 10.9 Corrections instituted for Round 5: • Increased post oven leaching residence time from 15 seconds to 45 seconds, and split post leaching to 20 seconds water only, followed by
  8. 8. 8 25 seconds Bioblox treatment. Pre Oven leach of 30 seconds of Bioblox treatment only continued. Round 5 resulted in the first improvement in protein levels against the “control” iteration. The best Bioblox bath resulted in a total overall protein reduction of about 20% - effective, but not considered impressive enough to warrant pursuit of production plant testing at that time. Rounds 6 and 7 focused on establishing the proper level of Bioblox concentration, testing various routines at both 0.5% and 1.0% active ingredient to water. This test overwhelmingly determined that the higher concentration of Bioblox™ did not benefit protein reduction according to the laboratory data, and that the level of 0.5% active ingredient appeared effective against protein removal. This proved to be a key statistic in the interest of keeping any material cost addition to the process, low. Testing continued on various grades of Bioblox™ through testing rounds 8, 9 and 10, including adjusting the leach water pH to determine if this had an impact on enhancing protein removal in tandem with Bioblox™. For all iterations, it was determined that normal water pH levels of 6.5 to 7.0 was the optimal level for Bioblox™ performance. When pH was raised (to approximately 12) or lowered (to approximately 3.2), the protein levels increased anywhere from 10% to 30%, from that of regular water pH levels. Round 11 yielded the most compelling results for protein removal, with the following major process change implemented for testing, which resulted in compelling protein reduction for several Bioblox™ versions:
  9. 9. 9 Many glove lines have 3 or more separate leach tanks for both pre oven and post oven leaching. Earlier results showed that Bioblox performed at a higher level by first exposing the glove to water only, before entering the Bioblox™ treatment stage. However, in no earlier testing was a residual water rinse subjected to the glove after the Bioblox™ exposure. For Round 11, the following leaching schedule was implemented, with all water temperatures remaining at 38 degrees C.
  10. 10. 10 Station Leach H20 only Bioblox™ Leach H20 only Total Leach Pre Oven Leach 10 seconds 15 seconds 10 seconds 35 seconds Post Oven Leach 15 seconds 20 seconds 10 seconds 45 seconds Testing for Round 11 yielded favorable protein reduction results as follows: Group IDGroup IDGroup IDGroup ID AdditiveAdditiveAdditiveAdditive LowryLowryLowryLowry mg/gmg/gmg/gmg/g LowryLowryLowryLowry mg/dm2mg/dm2mg/dm2mg/dm2 ELISAELISAELISAELISA mg/gmg/gmg/gmg/g ELISAELISAELISAELISA mg/dm2mg/dm2mg/dm2mg/dm2 QQQ Control 215 332 2.9 4.4 RRR Bioblox 3198 135 212 1.4 2.2 SSS Bioblox FA 65656565 106106106106 0.50.50.50.5 0.70.70.70.7 TTT Bioblox F 95 150 1.6 2.4 All Bioblox treatments benefited and improved in lab results by employment of a short residual water rinse after 0.5% concentration Bioblox™ treatment in the prior leach tank, preceded by another “water only” tank. It was perceived that the potential for Bioblox™ as a protein treatment was commercially viable, meeting all of the project objectives established during early testing in 2005.
  11. 11. 11 To further validate protein reduction potential of Bioblox™, samples consistent with the leaching process in Round 11 (water – Bioblox™ - water) were made at the pilot plant, and sent for FITkit® analysisFITkit® analysisFITkit® analysisFITkit® analysis. These highly sensitive tests use specific monoclonal antibodies developed against the four major latex allergens (Hev b 1, Hev b 3, Hev b 5 & Hev b 6.02) known to be present in NRL products. Group IDGroup IDGroup IDGroup ID AdditiveAdditiveAdditiveAdditive Hev b 1Hev b 1Hev b 1Hev b 1 Hev b 3Hev b 3Hev b 3Hev b 3 Hev b 5Hev b 5Hev b 5Hev b 5 Hev b 6.02Hev b 6.02Hev b 6.02Hev b 6.02 NNNN Bioblox NF Undect. Undect. 0.09 0.15 OOOO Bioblox FA Undect. Undect. 0.1 0.18 PPPP Control Undect. Undect. 0.24 0.48 QQQQ Bioblox L Undect. Undect. 0.04 0.08 RRRR Bioblox 3198 Undect. Undect. 0.24 0.28 Further testing was conducted in 2006 at a few manufacturing locations in Malaysia, yielding promising results. In one test, a “control” was implemented using normal Malaysian leach water and process temperatures of 60 degrees C. A total of 60 seconds of both Pre-oven leach and post oven leach was employed for the test. The Bioblox treatment, employed at 38 degrees C, demonstrated a reduction of approximately 10% to 15% in protein levels compared against “water only leaching” at typical elevated temperatures of 60 degrees C. This test
  12. 12. 12 demonstrated potential to achieve protein reduction better than existing methods, while conserving energy costs so vital to profitability. EquipmentEquipmentEquipmentEquipment ImplementationImplementationImplementationImplementation Bioblox™ in concentrate form is a liquid. Any dipping lines containing approximately 30 to 45 seconds pre-oven and post-oven leaching are candidates for simple installation of equipment necessary to implement the system on existing lines. The following is one suggested procedure: For example, in the case of BiobloxBiobloxBiobloxBiobloxTMTMTMTM LLLL, which is a 30% actives concentrate, the dosage rate would be 0.005X1000/0.3 = 16.67 mls of Bioblox™ LBioblox™ LBioblox™ LBioblox™ L per liter of leach water. This dosage level can be routinely controlled in leaching systems that drain continuously, by addition of a metering pump connected to a Bioblox™Bioblox™Bioblox™Bioblox™ holding tank or shipping drum (See Figures 1 and 2 below), or by gravity feed using a flexible feeding tube pinch system, metered via measured feed. Some Bioblox™Bioblox™Bioblox™Bioblox™ grades are more viscous by nature, which may require a metering pump system for best performance.
  13. 13. 13 Figure 1: EXAMPLE OF METERING PUMP FOR BIOBLOX™ (reference:Figure 1: EXAMPLE OF METERING PUMP FOR BIOBLOX™ (reference:Figure 1: EXAMPLE OF METERING PUMP FOR BIOBLOX™ (reference:Figure 1: EXAMPLE OF METERING PUMP FOR BIOBLOX™ (reference: www.dosatron.com)www.dosatron.com)www.dosatron.com)www.dosatron.com) Figure 2: INSTALLATION OF METERING PUMP WITH BYFigure 2: INSTALLATION OF METERING PUMP WITH BYFigure 2: INSTALLATION OF METERING PUMP WITH BYFigure 2: INSTALLATION OF METERING PUMP WITH BY----PASSPASSPASSPASS Bioblox™Bioblox™Bioblox™Bioblox™ is best used when employed in both pre-cure oven leaching and post-cure oven leaching systems. Best results are obtained by subjecting the in-process latex article to the following leaching schedule for pre-oven and post-oven leaching systems: • First Stage Leaching – water only
  14. 14. 14 • Second Stage Leaching – Bioblox™ treatment in water • Third Stage Leaching – water only (residual rinse) Residence times for each leaching stage may vary according to the manufacturer’s process and formulation, but the following minimal guideline may be used for initial trials and validation: • First stage leaching in water only – 15 seconds or more • Second stage leaching in water with Bioblox™ - 15 to 20 seconds or more • Third stage leaching in water only – 15 seconds or more It is possible that overall leach tank residence time may reduce from current manufacturer settings. Each manufacturer must make this determination based upon his/her evaluation and merit. If one pumps water from the last leach tank upstream to the first leach tank, it is important to by pass the Bioblox™ treatment tank with this procedure. The Bioblox™ tank is best planned as an isolated leach tank with its own incoming water line, and any overflow going to drain, not another leach tank. This is a necessary approach, as protein reduction will likely suffer if Bioblox overflow migrates to any upstream leach tank. Future TestingFuture TestingFuture TestingFuture Testing The following studies are planned for Bioblox™ treatment in the upcoming months:
  15. 15. 15 1. Potential to remove vulcanization residues for both NR latex and nitrile gloves. 2. Post process laundering benefits of Bioblox™ and impact on residual removal and proteins. 3. More detailed study on protein removal of polymer coated latex gloves. 4. Extended wear testing. 5. Physical parameters testing. 6. Optimization of Bioblox™ using cost-benefit analysis through concentration comparisons, saturated leach tank protein testing.

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