# Product Handling

The Dow Chemical Company Packaging and Converting July 2011

### Product Handling


### o Storage o Mixing o Filtering 

### o Pumping o Pot life o Disposal 

### o Shelf life/Storage life

o Viscosity control o Coat weight control 

### o Recirculation o Blend off o Clean - up

### Storage



### • Protect against exposure to moisture

– for isocyanate cure systems

• Drying tubes

• Replace contents with dry gas



### • Avoid temperature extremes

• Refer to technical data sheet for specific products

### Desiccant tubes

• For use with moisture

sensitive coreactants (such as Co

- F or Co

- CT)

• Used to dry the make

- up air when coreactant is drawn from a drum

• The pictured drier can be unloaded and the desiccant regenerated

• Single

- use cartridges are available

Image drawn from: www.drierite.com/catalog3/page6.cfm

### Dispensing drum rack

• Set

- up for dispensing adhesive and coreactant from drums

• High usage rate

• Drums on drum rack

• Top drums feed the lower set of drums

• When top is empty, take off and replace

• Note desiccant drying tubes on both adhesive and coreactant

• Can be fed into a meter/mix/dispense unit Image from: http://www.sealantequipment.com/materialpumps.htm

### Shelf life/Storage life

• Shelf life - The length of time that a sealed container of product stored under specified conditions will remain suitable for use.

• Use adhesive within recommended shelf life.

• Six months from date of receipt is default.

• See Data sheet for variances.

### Mixing

• Weighing
– Best practice is to mix on a weight basis

• Diluents

– Urethane grade solvents for all urethane 

### curing systems

– less than 0.05 % water, and less than 0.5 % alcohol

### Center Mixing Off
- Center Mixing

### Mixing?

### Mixing Equipment

• Portable mixer

http://www.premiermill.com/literature/premier/PDF/pm

- usf_unimixstand_pm.pdf

### Mixing Equipment

• Floor

- Standing Mixer

High speed mixer from Charles Ross and Sons

### Weighing/Tolerances

• Mix Ratio should be 

###  10%of TDS.

– 100/13 = 100/11.7 to 100/14.3

• A floor balance that is 

###  2 lb is fine for weighing 100 lb of A component ( 

###  2%).

• Not good for weighing 10 lb of coreactant ( 

###  20% mix error).

• Weigh coreactant in small pail on a more accurate balance and rinse into A component using part of dilution solvent.

### Batch Size Considerations



### • Size of mixing equipment -

– match mixer to size of vessel.



### • How much you intend to use -

– Generally not recommended to make up 

### more than 8 hours worth to be safest.



### • Pot life consideration

• Depends on ambient conditions, type of 

### chemistry and cleanliness of solvents.

### Mix Ratio

• Technical data sheet information

• Adhesive/coreactant ratio ± 10% of target

• Weight/weight basis

– Preferred for process control

• Volume basis

– Not recommended , likely to produce mixing errors

### Mix Ratio



### • Example:  Adcote 555 adhesive  Adcote 536B coreactant  An accounting exercise

### Mix Ratio



### • Definitions  NV, NVM = “non

- volatile” and “non

- volatile material” (also known as % solids)  Ethyl acetate = EtOAc  TDS info:  Adcote 555 = 70% solids (NVM)  Adcote 536B = 75% solids (NVM)  100:13 TDS mix ratio, wet/wet on a weight basis  “Wet/wet on a weight basis” means “as received” (out of the drum, pail or bucket)TDS Information for Adcote 555/536B  Adcote 555 Solids 70% (%NV), Weight/Gallon 8.5 lb

 Adcote 536B Solids 75% (%NV), Weight/Gallon 9.4 lb

 EtOAc = 7.4 pound per gallon (from any reference source)

 Mix ratio = 100:13

 Goal is to create a recipe at (as an example) 40% solids

 Build an “accounting” table

### Mix Recipe Table

1) From TDS, enter %NV and pounds per gallon of each component (ethyl acetate data can be found in a number of sources) 2) Mix ratio is 100:13. Enter “100” and “13” respectively. 3) Multiply 100 by 70% solids to determine the nonvolatile weight of Adcote 555. (100) x (0.70) = 70.0 4) Multiply 13 by 75% solids to determine the nonvolatile weight of Adcote 555. (13) x (0.75) = 9.75  9.8

### Mix Recipe (con’t)

4) Total the NVM weight column

70 + 9.8 = 79.8 5) Divide total of “NVM weight” column by 40% solids to determine the total batch weight. Enter in Weight column as the batch total weight 79.8  0.40 (40%) = 199.5 6) Subtract Adcote 555 and Adcote 536B weight from Total Weight amount. This difference is the amount of EtOAc to add. Enter in the table. 199.5

– (100.0 + 13.0) = 86.5

### Mix Recipe Table

7) Divide each component weight by (total weight  100) to get parts per hundred (Per cent)

199.5  100 = 1.995 100  1.995 = 50.1 (Adcote 555) 13  1.995 = 6.5 (Adcote 536B) 86.5  1.995 = 43.4 (EtOAc) 8) Total should be 100.0 (if not, check for errors) 9) This is the % recipe

– use this for volume and cylinder calculations later

### Mix Ratio

• Calculate volume from % recipe

– Now in a per cent basis  50.1  8.5 = 5.9 gal Adcote 555  6.5  9.4 = 0.7 gal Adcote 536B  43.4  7.4 = 5.9 gal EtOAc  Total 100.0 pounds adhesive  Total = 12.5 gal mixed adhesive  100/12.5 = 8.0 pounds per gallon mixed adhesive density (save for later)

### Mix Ratio

• Systematic approach for mix calculation

• Accounts for raw material inputs

• Mass balance

• Proper mixing and handling

• Optimum adhesive performance

### Area Calculation

• How much adhesive is needed to laminate a given job?

### Area Calculation

• Area calculations

• Need web width and length

• Need application weight

• Example:  2.5 million foot job  52 inches wide  1.5 pounds per ream

### Area Calculation

• 2,500,000 ft length x (52 in/12 in per foot) 

### = 10.8 million ft2 area = 10.8 x 10 6 ft 2



### • Ream = 3000 ft 2



### • 10.8 x 10 6 

### ft 2 

###  3000 ft 2 

### per ream = 3600 reams

### Area Calculation

• 3600 reams x 1.5 pounds per ream = 5400 pounds of DRY mixed adhesive



### • 5400 pounds  0.40 (40% solids) = 13,500 pounds of LIQUID mixed adhesive

### Area Calculation

• From the recipe (pph) we can calculate:

– 50.1% of the mixed adhesive is Adcote 555

• (13500) x (0.501) = 6764 pounds Adcote 555

– 6.5% is Adcote 536B

• (13500) x (0.065) = 878 pounds Adcote 536B

– 43.3% of the mixed adhesive is ethyl acetate

• (13500) x (0.434) = 5846 pounds ethyl acetate

### Area Calculation

• How much to make?

• How much to use?

• Enough inventory for the job

• Can be used for cost calculations

### Mixing

• Pre - mix minimum of 15 minutes

• Size blade to size of container

• Mild Vortex, avoid entrapping air

• Move material off bottom of drum

• Continuous gentle mixing

### Top - down Mixing

Animations courtesy of Dr. Thomas A. Post, Post Mixing Optimization and Solutions

### Bottom - up Mixing

Animations courtesy of Dr. Thomas A. Post, Post Mixing Optimization and Solutions

### Floor Balance

• Used to weigh out coreactant

• Tare container, fill and drain, tare again

• Provides a better “drain” tare than empty container alone

• Weigh and add using weight difference

Image from: http://us.mt.com/us/en/home/products/Industrial_Weighing_Solutions.html

### Viscosity Control

• Viscosity - A measure of a fluid’s resistance to flow.

• Flow behavior is an indication of process ability.

• Establish the appropriate viscosity to maximize the quality and consistency of the adhesive application.

• Take measures to prevent/limit solvent loss.

### Brookfield Viscosity

• In the lab a Brookfield Viscometer can measure viscosity more consistently and accurately than Zahn Cups.

Brookfield Viscometer

### Efflux Cup Viscosity

• Inspect cup for damage.

• Stir solution thoroughly, 

### but avoid entrapping air.

• Limit solvent loss.

• Immerse Cup completely to below surface of liquid. Shell cup

Zahn cup

### Zahn Cup Viscosity

• Lift the cup crisply, keeping the handle vertical.

• Start timer when top of cup breaks surface of liquid.

• Hold cup about 6 inches above surface.

• Stop timer when stream first breaks.

### Coating Weight Control

• Appropriate weight to achieve desired performance and appearance.

• Inadequate and/or inconsistent coating weights are often source of problems.

• Monitor Coat Weight and Viscosity.

### Recommended Coating Weights
Solventless: 0.8 - 1.3 lb/ream (1.3 - 2.1 g/m 2 ) Water - based: 1.5 lb/ream (2.5 g/m 2 ) Solvent - based: 1.75 - 3.0 lb/ream (2.9 - 5.0 g/m 2 ) Heat seal coatings:

3.5 - 4.5 lb/ream (5.7 - 7.3 g/m 2 ) Primers: 0.5 - 1 lb/ream (0.8 - 1.6 g/m 2 )Monitor Coat Weight and Viscosity 

## Increasing Viscosity Means

• If coat weight is gradually increasing solvent is being lost.

• Adjust viscosity with appropriate solvent, Recheck coat weight.

• If coat weight is not increasing pot life is reaching its end.

• Consider making up new adhesive batch.

### Factors Reducing Pot Life



## • High Humidity

• High Temperature



## • Moisture in Solvents

• Moisture in Adhesive

### Pumping



### • Application

– Feed from drum to sump

– Feed from sump to applicator



### • Types

– Diaphragm

– Peristaltic



### – Centrifugal

– Positive displacement (Bran & Luebe)

### Diaphragm Pump

• Diaphragm pumps are very common and come in many sizes.

• The pumps operate continuously but have a safety valve which returns fluid to the input side of the pump if pressure rises above a set level.

### Double Diaphragm Pump

• Simple valve system to move the DIAPHRAGM ROD.

• The PILOT SPOOL is pushed back and forth allowing air to move the Air Distribution Valve back and forth. The AIR DISTRIBUTION ROD controls air flow to the left or right air chamber, reversing on each stroke. The four BALL VALVES are free floating and operated by pressure differences in the pumped liquid.. Liquid flow is from the bottom to the top.

### Peristaltic Pump

### Peristaltic Pump

• In this example three rollers on rotating arms pinch the tube against an arc and move the fluid along.

• One of the main advantages - Cleanliness.

## Disc Pump

### Centrifugal Sump

Pump

### Sump or Reservoir

Images drawn from www.indco.com

### Recirculation



### • Minimize foam generation

– Keep return distance short

– Return to bottom of sump, below fluid level

– Keep return as far from intake as possible

– Keep sump as full as possible



### • Cover to minimize solvent loss.

### Filtering

• A filter in the return line is recommended to remove debris, trapped foam etc.

• Simple as cheese cloth.

• Elaborate cartridge systems.

• Magnetic particle filter.

### Clean - up



### • Short breaks

– Solventless: Dump adhesive and wipe rolls with solvent.

– Solvent - based: Keep cylinder wetted 

### with adhesive. Prevent solvent loss.

– Water - based: Keep cylinder wetted with adhesive. Prevent skinning.



### • Clean the smoothing bar each & every time the line stops.

### Blend - off

• Generally discouraged. Never blend - off solventless mixes.

• Blend older mixes, such as those held overnight, at 10 - 20% level with fresh mixes. Adjust the viscosity as needed.

### Disposal

• Contact your local EPA for specific regulations.

• Refer to the MSDS regarding precautions or protective equipment in the event of a spill.

### Good Product Handling



## • Important For Consistent Results



## – Weighing



## – Mixing Practices

– Coat Weight Control