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ANTIOX PC-X

Organic Protective Coating for SMOBC/SMT Circuit Boards

Description:

ANTIOX PC-X is an Organic Protective Coating (OPC) which replaces solder re-flow for protection and solderability maintenance of SMOBC and SMT circuit boards, keeping them in solderable condition for as long as two years.

ANTIOX PC-X is applied by dip or spray, and is easily controlled for long bath life and consistent, repeatable results.

ANITOX PC-X coated panels have been subjected to test mediums which include a two year simulation of bagged warehouse storage; humidity tests per MIL-STD-810D, Method 507.2, procedure II, a test designed to simulate unventilated conditions that may occur during storage or transit of sealed items. ANITOX PC-X boards have also been subjected to a variety of other temperature/humidity and S.I.R. studies.

ANTIOX PC-X lends itself readily to automation with residence times as low as one (1) minute.

 

Benefits:
  • Cost savings over solder-dip-and-reflow exceed 90%
  • Eliminates problems of eutectic incompatibility
  • Eliminates component slippage in SMT applications
  • Eliminates uneven solder re-flow problems
  • Significantly reduces air pollution problems

 

Properties:

Form:                              Fluorescent yellow liquid
pH (as supplied):          6.0 to 6.5
Specific gravity:           1.04 @ 60°F
Weight/Gallon              8.678 lbs
Solubility, water:          Infinite
Flash point:                   >200°F
Odor:                              Mild, characteristic

Applications:

ANTIOX PC-X is a concentrated, highly refined product designed specifically for coating of SMOBC, Flex circuits, and SMT boards by dip or spray application methods.

 

Directions For Use:

Bath Make-up:                             20% by volume with D.I. water
Temperature:                                  140°F ± 5° F
Time:                                              1 to 1 1/2 minutes
Concentration:                             100% to not less than 60% bath strength.
Filtration:                                       Required
Operation:                                     Immersion or spray

Equipment:

TANKS: polypropylene, PVC, PVDC, Stainless Steel, Mild Steel

HEATERS: Mild Steel, Stainless Steel, Quartz

PUMPS: Mild Steel, Stainless Steel, Brass, Bronze, Rubber and Plastics of all kinds

FILTER HOUSING: PVC or Steel

FILTER ELEMENT: Hytrex II molded polypropylene 10 to 20 micron cartridge type or equivalent

PLUMBING: PVC, polypropylene, copper or galvanized pipe.

 

Process Flow:

The process consist of: (1.) Cleaning the boards of any handling oils and oxides: (2.) Micro-etch to the surface uniformity: (3.) Oxide/smut removal and base coat with ANITOX SP: (4.) Coat with ANTIOX PC-X: (5.) Rinsing: (6.) Forced air dry, and post bake.

  1. Acid Cleaner: DURACLEAN LPH or DURACLEAN LPH-10. 1 to 3 minutes. Rinse, D.I.
  2. DURATECH 310 to surface uniformity. 1 to 3 minutes. Rinse, D.I.
  3. 10% Sulfuric Acid/Antiox SP @ 5%. 30 seconds to 1 minute. Rinse, D.I.
  4. Antiox PC-X. 1 to 1 1/2 minutes at 140°F. Rinse, D.I.
  5. Hot D.I. tank rinse @ 150°F. 15 seconds.
  6. Hot forced air dry and post bake. 15 minutes @ 160°F

Note: It is important that all water be blown from the boards before the final bake.

 

Bath Maintenance:

BATH STRENGTH: Bath must be maintained between 60% and 100% (see titration procedure and replenishment guide)

BATH pH: It is critical that pH be maintained between 4 and 6.5. Do not allow pH to drop below 4 or exceed 7. Bath MUST NOT be allowed to go to the alkaline side of the pH scale. Adjust acidic pH with a reagent grade sodium carbonate. Adjust alkaline pH with 1.0 Normal sulfuric acid.

BATH CLEANLINESS: A recirculating 10-20 micron cartridge type filter is necessary to keep hard water precipitates and drag-in contaminates out of the bath. Continuous filtration is a must.

PLUMBING: For tank operation with overflow rinse module(s), it is not important that the ANTIOX rinse module not flow back into the module preceding it.

NOTE: Daily pH adjustments will shorten the life of the bath due to a buildup of carbonate salts. The need for such adjustments is the result of acid drag-in due to inadequate rinsing of the ANTIOX SP/sulfuric acid bath preceding ANTIOX PC-X.

 

Antiox PC-X Bath Control:

Titration procedure:

  1. REAGENTS
    1. 0.1 normal silver nitrate
    2. 0.1 normal ammonium thiocyanate
    3. Concentrated ammonium hydroxide (30%)
    4. Concentrated nitric acid (70%)
    5. AR grade ferric ammonium sulfate
    6. Distilled water
  2. APPARATUS
    1. Beaker, 500 ml
    2. One 20 ml pipet
    3. One 50 ml buret
    4. One 10 ml pipet
    5. A 100 ml measuring cylinder
    6. A 500 ml Buchner flask & funnel
    7. No. 5 Whatman filter paper (5.5 cm paper for 6 cm funnel)
    8. Whatman cellulose powder, grade CF1
    9. Wash bottle
    10. Vacuum pump (Nalgene #6130-0020)
  3. INDICATOR SOLUTION
    1. To 80 gms AR ferric ammonium sulfate add 10 ml concentrated nitric acid
    2. Add distilled water to 200 ml
    3. Stir with mild heat until clear
  4. PROCEDURE
    1. Pipet 10 ml sample from bath into 500 ml beaker.
    2. Add 125 mil of distilled water or chloride free D.I. water; 5 ml of concentrated ammonium hydroxide; and 20 ml of 0.1 normal silver nitrate. Stir well and let stand for 5 minutes to allow coagulation of the precipitate.
    3. Add 3 to 4 grams of cellulose powder to aid filtration and filter suspension through Buchner funnel using #5 Whatman paper. Be sure to transfer all of the solution and precipitate.
    4. Wash beaker with 3 X 50 ml portions of distilled water, and pour each increment through funnel to flush the filter cake. Return filtrate and washing to the beaker from the Buchner flask.
    5. Slowly stir 10 to 15 ml concentrated nitric acid into filtrate.
    6. Add one (1) ml of indicator (#3).
    7. Titrate to a pale orange end point with 0.1 normal ammonium thiocyanate.
  5. CALCULATIONS
    1. ml of titrate X 9.8 / 1.8354 = ml/liter
    2. Divide milliliters by 1000 to get % by volume

     

Titration procedure for ANTIOX PC-L:

  1. REAGENTS:
    1. Silver nitrate, 0.1 normal
    2. Amm Hydroxide AR Grd (30%)
    3. Nitric Acid, AR Grd (70%)
    4. Ferric ammonium sulfate, AR Grd. (crystals)
    5. Ammonium thiocyanate, 0.1 normal
    6. Distilled water (chloride free)
  2. APPARATUS:
    1. 500 ml beaker
    2. One 5 ml pipet
    3. Two 10 ml pipets
    4. One 50 ml buret
    5. A 50 ml & 100 ml measuring cylinder
    6. A 500 ml Buchner funnel & vacuum flask
    7. No 5 Whatman filter paper (5.5 cm for 6 cm funnel)
    8. Whatman cellulose powder, type CF-1
    9. Vacuum pump (Nalgene #6130-0200)
  3. INDICATOR SOLUTION
    1. To 80 grams of AR Grade Ferric Ammonium Sulfate, add 10 ml of concentrate (70%) Nitric Acid
    2. Add distilled water to 200 ml
    3. Stir with mild heat
    4. Bottle and label
  4. PROCEDURE:
    1. Pipe 10 ml sample from working bath into 500 ml beaker and add 125 ml distilled water
    2. Add 5 ml conc Ammonium Hydroxide and 10 ml of 0.1 Normal Silver Nitrate. Stir well and let stand for 5 minutes to allow coagulation of precipitate.
    3. Add 3 gms of cellulose powder to aid filtration. Mix well and vacuum filter through the Buchner funnel using #5 Whatman paper. Be sure to transfer all the solution and precipitate.
    4. Wash beaker with 3 X 50 ml portions of distilled water. Pour each increment through the filter allowing the vacuum to dry the filter cake between each flushing return clear, filtered solution to the 500 ml beaker.
    5. Slowly stir 10 ml conc. Nitric acid into clear filtrate.
    6. Add one (1) ml of indicator (#3)
    7. Titrate to a pale orange end point with 0.1 normal Ammonium Thiocyanate.
  5. CALCULATIONS
    1. Percent bath strength = [(A X N1) - (B X N2)] X 1.2693
    2. The above is calculated where:
      • A= ml of silver nitrate added.
      • N1= normality of silver nitrate
      • B=ml ammonium thiocyanate used
      • N2=normality of ammonium thiocyanate.
    3. Calculation X 100 = percent (%)
  6. REPLENISHMENT:
    1. Determine bath strength in percent
    2. Using the % bath strength guide below, for every ten (10) gallons of working bath add ANTIOX PC-X concentrate according to the schedule shown:
      • 100%                              0
      • 90 %                               0.2 gallons/757 ml
      • 80 %                               0.4 gallons/1514 ml
      • 70 %                               0.6 gallons/2271 ml
      • 60 %                               0.8 gallons/3028 ml
      • 50 %                               1.0 gallons
      • 40 %                               1.2 gallons
    3.  Example: a 60 gallon bath at 80% would require 2.4 gallons of ANITOX PC-X to bring it back to 100%. 60 gals / 10 X 0.40 = 2.4 gallons of PC-X

Testing of Treated Board:

Two (2) tests may be employed to determine the presence of ANTIOX PC-X on the copper and the adequacy of treatment. This is best done with periodic dedicated test panels.

  1. SILVER NITRATE TEST (AgNO3):
    1. Dilute tenth normal (0.1N) Silver Nitrate with three (3) parts distilled or chloride free D.I. water. This equals .025N AgNO3 Put in a brown dropper bottle to exclude light.
    2. Place one drop of .225N AgNO3 on a treated copper surface. Drop should not exhibit a color change for 15 seconds. Test should be performed after final post-bake.
  2. NITRIC ACID TEST (HNO3)
    1. Dilute 5 parts D.I. water with one (1) part 90% Nitric Acid for a 15% solution. Place in a convenient dropper bottle. NOTE: Always add the acid to water. Never add water to strong acids.
    2. Place one drop of 15% Nitric Acid solution on treated copper. Look closely for bubble formation indicating the Nitric Acid is penetrated the coating and is reacting with the copper. Time to first bubble formation should exceed one (1) minute. Test should be performed after final post-bake and storage for at least 8 hours.

NOTE: During storage for the first several days after final post-bake the ANTIOX PC-X continues to "setup", becoming denser and more resistant to adverse environmental influences.

 

Fluxing:

ANTIOX PC-X treated copper must be fluxed with a sufficiently active flux to allow good wetting of hot solder; and SMT solder pastes must be sufficiently active for good adhesion to result

Always test before committing boards to production.

 

Safety:

ANITOX PC-X presents little hazard. It contains Dipropylene Glycol Methyl Ether which date has not been found to have any significant health effects. When handling this product avoid contact with eyes. In case of eye contact flush immediately with copious quantities of fresh, cool water. Obtain medical attention. Take precautions to prevent prolonged or repeated skin contact. Wash contaminated skin with soap and water. Remove contaminated clothing and wash before reuse.

Provide adequate ventilation.

 

Disposal:

Check with local EPA office for information on putting Dipropylene Glycol Methyl Ether to the sewer. The working ANTIOX bath will contain 3.6% by volume of this chemical. Other materials present in ANTIOX are either not regulated or are biodegradable and have no effect on waste water treatment systems.

 

Storage:

Keep containers sealed. Keep partial containers closed at all times. Store product away from sources of excessive heat.

 

Shelf Life:

Anitox is guaranteed for (1) year from date of receipt in unopened containers.

 

Containers:

Five gallon pails and 55 gallon nonreturnable plastic drums.

 

Classification:

National Motor Freight Classification NO. 44620, water-based glycol solution
DOT Hazardous Material Description: Not regulated

 

The information contained herein is based on our experience and is believed to be reliable. However, since methods and conditions of use of our products as described are beyond our control, both the product and instructions for its use are offered without warranty, expressed or implied. No information on this data should be construed as a recommendation by DURATECH INDUSTRIES, INC., to use any product in contravention of any patent right.

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