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APPENDIX E
Proposed Draft Standard Specification
for PCR MCR High-Density PE Bottles
for Use in AASHTO-Approved Corrugated
Drainage Pipe
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DRAFT
____________________________________________________________
Draft Standard Specification for
Post-Consumer Recycled Mixed-Color Reprocessed High
Density Polyethylene Bottles for Use in AASHTO Approved
Corrugated Drainage Pipe
AASHTO Draft Standard XXX-XX
____________________________________________________________
1. SCOPE
1.1 This specification covers the quality of post-consumer recycled, mixed-color,
reprocessed, high density polyethylene bottles for use in AASHTO approved
corrugated drainage pipe.
1.2 This specification presents a set of properties to be met for the resin.
1.3 This specification can be used by recycled resin suppliers as part of
manufacturing quality control (MQC), or by pipe manufacturers or independent
bodies as manufacturing quality assurance (MQA).
______________________________________________________________________
2. REFERENCED DOCUMENTS
2.1 ASTM Standards:
D638, Test Method for Tensile Properties of Plastics
D792, Test Methods for Density and Specific Gravity (Relative Density) of
Plastics by Displacement
D1238, Test Method for Melt Flow Rates of Thermoplastics by Extrusion
Plastometer
D1505, Test Method for Density of Plastics by the Density-Gradient
Technique
D4218, Test Method for Determination of Carbon Black Content in
Polyethylene Compounds By the Muffle-Furnace Technique
D4703, Practice for Compression Molding Thermoplastic Materials into Test
Specimens, Plaques, or Sheets
D5630, Test Method for Ash Content in Plastics
______________________________________________________________________
3. TERMINOLOGY
3.1 Post-Consumer Recycled HDPE (PCR-HDPE) Polyethylene that has been
discarded by consumers after use, then collected, cleaned, and washed. The
density is greater than 0.940 g/cm3 and typical sources include primarily bottles
and some bags.
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3.2 PCR-HDPE Regrind Post-Consumer Recycled HDPE that has been cleaned,
washed and ground into plastic chips.
3.3 Reprocessed PCR-HDPE Post-Consumer Recycled HDPE that has been
cleaned, washed, melt-filtered, and pelletized. Commonly known as "Repro."
3.4 Mixed-Color PCR-HDPE Post-Consumer Recycled HDPE that is composed of
mostly colored detergent bottles.
3.5 Natural PCR-HDPE Post-Consumer Recycled HDPE that is composed of milk
bottles.
______________________________________________________________________
4. PROPERTIES
4.1 The required properties for PCR mixed-color reprocessed resin are given in
Table 1.
4.2 Specific details of the tests are found in Section 7.
Table 1. Required properties for PCR mixed-color reprocessed resin.
Property Test Method Sample Specified Frequency
Value
Density ASTM D1505 Pellets/Plaque 0.945-0.960 1 per shift
ASTM D792 g/cm
Melt Index ASTM D1238 Pellets/Plaque <0.60 g/10 min 1 per shift
190°C/2.16 Kg
% Volatiles 175°C/1 Hour Pelletsa <0.2 % Certifyb
% Ash ASTM D5603 Pellets/Plaque <1.5 % 1 per shift
% PP DSC Plaque <10.0 % 1 per lotc
Yield Stress ASTM D638d Plaque >3500 psi 1 per lot
(psi)
Break Strain ASTM D638e Plaque >100 % 1 per lot
(%)
a
Tested on pellet samples before melt blending.
b
Manufacturer will provide a certificate stating their material will lose less than 0.2% of its weight when a
2.000 ± 0.100 g sample is heated at 350°F for 1 hour.
c
A production lot is defined as either a truckload, or one compartment of a railcar. Its weight is generally
between 40,000 and 50,000 lb.
d
Strain rate shall be 2.0 in. per minute.
e
Assume 2.0-in. gage length.
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______________________________________________________________________
5. SAMPLING
5.1 A production lot shall be considered as a truckload or shipping container full of
1,500 lb boxes of resin, or one compartment of a railcar. The weights normally
fall between 40,000 and 50,000 lb.
5.2 A truckload shall be sampled by obtaining 0.5 lb of material from each of eight
boxes, for a total of 4 lb of resin. Combine the eight samples to form a lot
sample.
5.3 A compartment of a railcar shall be sampled by obtaining 2 lb from the top and 2
lb from the bottom of the compartment. Combine the two samples to form a lot
sample.
5.4 The entire lot sample shall be dry blended before sample preparation. A
convenient way to do this is by hand in a 5-gallon plastic pail.
5.5 Divide the lot sample into two; one for immediate testing and the other for
validation testing, should the need arise. The back-up sample shall be kept for 90
days after the resin is sold.
5.6 Clearly label the sample and include a traceable production number and a date.
______________________________________________________________________
6. SAMPLE PREPARATION
6.1 Homogenize about 2 lb (900 g) of material by melt blending without filtration,
preferably with a twin screw laboratory extruder. A two roll mill is also
acceptable.
6.2 The blended material shall be compression molded according to ASTM D4703,
with the use of a 15°C/min cooling rate.
6.3 The plaque shall be 1.9- 0.08-mm (0.075- 0.003-in.) thick.
6.4 The plaque shall be allowed to equilibrate at standard laboratory conditions
(72°F, 50% RH) for at least 12 hours before tensile testing.
______________________________________________________________________
7. TEST METHODS
7.1 Test Conditions Unless otherwise specified in the test methods or in this
specification, conduct tests at the standard laboratory temperature of 23 2°C
(73.4 3.6°F).
7.2 Density Test methods ASTM D1505 or D792 are acceptable. Make three
separate determinations using separate homogenized pellets or separate
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portions of a plaque. The plaque thickness shall be 1.9 0.08 mm (0.075 .003
in.). Calculate and report the average and standard deviation from the mean.
7.3 Melt Index Test method ASTM D1238, using Condition 190/2.16. Make
duplicate determinations on either pellets or a plaque and calculate the average.
7.4 % Volatiles This test will be performed in aluminum pans that have been
heated at 350°F (177 °C) until they obtain a constant weight.
7.4.1 Test duplicate samples.
7.4.2 Weigh 2.000 ± 0.100 g of pellets or a plaque to an accuracy of three places past
the decimal point into an aluminum pan.
7.4.3 Place the pan in a forced-air recirculating oven preheated and stabilized to 350 ±
5°F (177 2°C) for a period of 1 hour.
7.4.4 Remove the pan and let it completely cool to room temperature in a desiccator.
7.4.5 Reweigh the pan and calculate the percentage weight loss of the sample. Report
the average to the nearest 0.01%.
7.5 % Ash - Test method ASTM D5630, Procedure B.
7.5.1 Sample size shall be 1g.
7.5.2 Heat at least 10 minutes at 800°C.
7.5.3 Test in triplicate samples.
7.6 % Polypropylene
7.6.1 Generate a melting curve by differential scanning calorimetry (DSC) at a heating
rate of 10°C/min. See Figure 1.
7.6.2 The curve shall be expanded to a range that includes the end of the HDPE peak
and the complete PP peak. See Figure 2.
7.6.3 Integrate the curve from a flat point before the PP melting to a point where the
PP curve returns to baseline.
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0
-1
Heat Flow (W/g)
-2
-3
-4
20 40 60 80 100 120 140 160 180 200
Exo Up Temperature (°C) Universal V4.5A TA Instruments
Figure 1. DSC curve of HDPE containing PP generated.
7.6.4 Mark the point where the HDPE melt returns to baseline. The end of the HDPE
melt and the beginning of the PP melt will not necessarily be the same point.
-0.56
150.59°C
-0.58 2.568J/g
142.71°C
-0.60
Heat Flow (W/g)
-0.62
162.84°C
-0.64
-0.66
130 140 150 160 170 180
Exo Up Temperature (°C) Universal V4.5A TA Instruments
Figure 2. DSC curve of HDPE containing PP expanded.
7.6.5 Record the HDPE end-of-melt temperature and the PP heat of fusion in J/g.
7.6.6 Calculate the theoretical heat of fusion for 100% polypropylene for the portion of
the PP melting curve that does not overlap with HDPE by:
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Y = -0.035X2 + 8.851X 475.6 (1)
Where: X = HDPE end-of-melt temperature (°C)
And Y = Hf of 100% PP not overlapped with HDPE.
For X = 142.7, Y = 74.7 J/g.
7.6.7 Calculate the percentage PP by:
%PP = Hf sample/ Hf 100% PP x 100 (2)
For Hf sample = 2.57 J/g, %PP = 3.4 %
7.6.8 Test two specimens from different parts of the molded plaque and report the
average.
7.7 Yield Stress/Break Strain Test ASTM Method D638, with Type IV dumbbell, 2-
in./min crosshead speed.
7.7.1 Test five specimens, individually measured for thickness.
7.7.2 Assume 1.3-in. gage for yield stress and 2.0-in. gage length for break strain. Use
crosshead to follow displacement.
7.7.3 Report 5 results, average, and standard deviation.
______________________________________________________________________
8. RETEST AND REJECTION
8.1 If any failure occurs, the material shall be retested to establish conformity in
accordance to the specified property. A second failed result will result in
rejection of the lot for the purposes of this specification.
______________________________________________________________________
9. CERTIFICATION
9.1 Upon request of the purchaser in the contract or order, a manufacturer's
certification that the material was manufactured and tested in accordance with
this specification, together with a report of the test results, shall be furnished at
the time of shipment.
