Crystallization Behavior and Film Properties of Nylon 66-rich Nylon 66/6 Copolymers

Jacob Ray, Tariq S. Oweimreen, Scott E. Powers and Douglas C. HoffmanAscend Performance Materials, Cantonment, FL 32533

Outline Introduction to nylon 66 and nylon 66 copolymers

Background on nylon 66 copolymers

Crystallization behavior of nylon 66 copolymers

Film properties of nylon 66 copolymers

Monolayer blown films

Biaxially oriented films

Laminate films containing nylon 66 copolymers

Summary

2

Nylon end uses are highly concentrated in food packages primarily as a protective layer

Where are Nylons Used in Films

Food80%

Non-food20%

Film Market by Nylon Type

PA6~85%

PA6-66 ~8%

PA66~3%

Specialty PA ~4%

• Nylon 6 – dominate material in polyamide films with the usage primarily in two processing technologies:

• Biaxially oriented polyamide (BOPA)• Blown multi-layer films

• Nylon 66 – largely limited application space due to marginal processability

Source: PCI, “The Opportunity for Polyamide in Film Production”

Why nylon?- Useful at food preparation temperatures.- Gas barrier properties help preserve food and block

odors during storage.- High strength and toughness

Food applications: 1B lbs./yr

Non-food applications: 0.3 B lbs./yr

Film properties has led the search for paths to attain Nylon 66 type performance in films

Advantages and Disadvantages of Nylon 66 in Film

• High melting point• High strength• High stiffness• High toughness• High puncture resistance• Creep resistance• Flex-crack resistance

4

Advantages Disadvantages

• High crystallization temperature• Fast crystallization• Poor aesthetics – limited clarity/gloss

Blending with other nylons has been the historical approach to increasing the processing window of Nylon 66

Applications of Nylon66 in FilmBlends of Nylon 66 and Nylon 6 are used to enhance processing limitations in blown film

5

Copolymers provide wider processing window

DSC thermograms of Nylon 66, Nylon 6 and blends

Ref: Nylon Plastics Handbook (M. Kohan 1995)

Nylon 66/6 Copolymer Melting BehaviorEffect of caprolactam level on copolymer melting point

6

Melting Points of Nylon 6,6 / 6 Copolymers

150

160

170

180

190

200

210

220

230

240

250

260

270

0 10 20 30 40 50 60 70 80 90 100Nylon 6 (%)

Tm (C

)

100% PA66 100% PA6Percent Nylon

Tm (°C)

Nylon 66 rich backbone enables a wider melting point range than Nylon 6 based copolymers

Nylon 66/6 copolymers

Nylon 6/66 copolymers

Nylon 66 Nylon 6Modification Level (wt.%)

Thermal Behavior of Nylon 66 Rich CopolymersMelting point depression follows Flory equation indicating random copolymers

7

°

1𝑇𝑇𝑚𝑚

−1𝑇𝑇𝑚𝑚

= −RΔHu

ln X°

Sample Caprolactamwt.%

Caprolactammole %

RV Tm(°C)

Tc(°C)

PA66 0 0 180 260 220

PA6694/66 6.0 11.3 180 255 205

PA6690/610 10.5 19.0 180/90 245 190

PA6684/616 16.3 27.6 130/85 235 175

PA6677/623 23.1 37.5 140/90 220 150

PA6 100 100 140/80 220 1701.8

1.9

2.0

2.1

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

1000

x 1

/T (1

/K)

-ln X

8Half-time analysis yields useful data to support development of processing recommendation on existing equipment

Isothermal Crystallization Half-time DSC Thermogram

Test procedure:1. Heat the sample from 25°C to 305°C.2. Holding for five minutes and then

cooling at 200°C/min. to the target isothermal temperature.

3. Hold at the desired temperature until the recrystallization exotherm is complete.

Data Analysis:1. The crystallization half-time (t½) is the

time when 50% of the recrystallization exotherm is complete.

For this sample t½ = 25.24 min (1514 s).

25.24min239.99°C50.00%

18.72min

240.01°C20

40

60

80

100

Area

per

cent

(%)

240

245

250

255

260

265

Tem

pera

ture

(°C)

-20.90

-20.85

-20.80

-20.75

-20.70

Heat

Flo

w (W

/g)

19 24 29 34Time (min)

y

Exo Up Universal V4.5A TA Instrumentst½ t½

Crystallization Behavior of Nylon 66 copolymers

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100 120 140 160 180 200 220 2401

10

100

1000

10000

PA66PA6690/610

PA6PA6677/623

Sem

i-Cry

stal

lizat

ion

Tim

e (s

ec)

Temp. (oC)

Fast - limitedflexibility andcompromised clarity

PA6 – like behavior but with higher Tm

~ 5x slower than PA6

Reducing crystallization rate enables use of PA66 copolymers in classical film processing technologies such as blown film and biaxial oriented film

Nylon 66 copolymers produce resins with crystallization behavior suitable for processing on existing equipment

For both Dart Drop and Elmendorf Tear the PA66 Copolymer containing 23 wt.% caprolactam yields the highest values

Film Properties of Nylon 66 rich copolymers1 mil monolayer blown films – Dart Drop and Elmendorf Tear

10

°

PA6694/66 PA6690/610 PA6684/616 PA6677/623 PA 6

Dart Drop (g) Elmendorf Tear (g)

PA6694/66 PA6690/610 PA6684/616 PA6677/623 PA 6

PA Type PA Type

Film samples conditioned at 23°C ± 3°C and 50% RH ± 5% for at least 40 hrs prior to testing.

PA66 rich copolymers can be manufactured using existing Nylon 6 BOPA assets and conditions

BOPA Film manufacture of Nylon 66 rich copolymers

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Stress/Strain Profile Maximum Stretch Ratios to Break

40% lower initial stretch force

Up to 25% higher in MD Up to 50% higher in TD

PA6690/610 PA6684/616 PA6677/623 PA 6

PA6

PA6677/623

Higher elongation at break

Majority of Film properties do not varying significantly with Nylon type except for Puncture Resistance

Effect of Nylon type on BOPA Film PropertiesResults from Sequential Stretching biaxial film line

Property Units PA6 PA6690/610 PA6684/616 PA6677/623Stretch Ratio 3 x 3 3 x 4.7 3.5 x 4.1 4 x 4Thickness µm 14.3 17.9 16.1 13.5Tensile StrengthMD MPa 265 270 300 287TD MPa 258 324 320 258ElongationMD % 100 100 80 70TD % 90 70 110 80Barrier Properties @ 23°C and 50% RHO2 Transmission Rate cc/day-atm 55 61 63 63Puncture, 1.6mm pinPuncture Resistance(Normalized) N/mm 1910 2670 2320 2280

Optical PropertiesTransmission % 92.0 92.2 92.3 92Clarity % 96.3 99.7 99.4 97.9Haze % 3.0 1.1 2.2 3.6Shrinkage @ 160C, 5 minMD % < 2.0 < 1.5 < 1.0 < 5.0TD % < 1.5 < 1.5 < 1.0 < 2.0

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9 10 11 12 13 14 15 16 17 18 19 20

25

30

35

40

45

50 PA6 Vydyne 833F (Tm = 220 oC) Vydyne 833C (Tm = 235 oC)

Punc

ture

For

ce (N

)

Thickness (microns)

40% Higher puncture

40% less film

BOPA Film made from Nylon 66 copolymers provide unique performance compared to Nylon 6 based BOPA 13

End user choice:

• Delivering unmet toughness requirements in new and existing applications compared to PA6 based BOPA film

• Same performance as PA6 based BOPA film but using thinner film

Benefits of Puncture ImprovementToughness vs. Thickness

PA6684/616■ PA6

Ascend 25kg pellet bags are made from a 4 ply structure containing 15 micron PA6 based BOPA Film

Application Development StrategyExploring translation of monolayer film properties to BOPA Film laminates

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4 Ply Plastic Film Construction

Partner Development Model: (Pull through activation)

Ascend BOPA Film Producer

Bag Manufacturer Ascend

BOPET film

Aluminium Foil

BOPA film

LLDPE film

Adhesive

Reverse printing

Adhesive

Adhesive

Film Suppliers

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Comparison of BOPA Film Type on Laminate Puncture15 micron BOPA film in an 180 micron Al foil laminate

Laminates with Nylon 66 copolymers BOPA film show 5-30% improvement in Slow Rate Puncture Tests vs the Control

0.00

0.05

0.10

0.15

0.20

0.25

833F 833C Control Bag

Energy to Break (J)

0

10

20

30

40

50

60

70

80

833F 833C Control Bag

Force to Break (N)

PA6677/623 PA6684/616 Control Bag PA6677/623 PA6684/616 Control Bag

Testing Speed = 25 mm/inTesting Pin = 1.6 mm radius

Enhancing Puncture Resistance15 micron BOPA film in an 180 micron Al foil laminate

~ 10% of structure is Nylon• 35% improvement in puncture force• 45% improvement in puncture

Monolayer Film Foil-based Laminate Film

16Higher film puncture resistance translates to increased puncture in laminate structures

0

500

1,000

1,500

2,000

2,500

PA66/6-16 Bag

Puncture Force (N/mm)

PA6684/616 PA 6

100% of structure is Nylon• 20% improvement in

puncture force

0

100

200

300

400

PA66/6-16 Bag

Puncture Force (N/mm)

PA6684/616 Control Bag0.0

0.2

0.4

0.6

0.8

1.0

1.2

PA66/6-16 Bag

Puncture Energy (N/mm)

PA6684/616 Control Bag

Summary• Nylon 66 rich copolymers are a preferred option for addressing processing

limitations of Nylon 66 compared to Nylon 66/Nylon 6 blends

• Nylon 66 copolymers containing caprolactam can be engineered to provide tailored processing characteristics

• Monolayer blown films of Nylon 66 copolymers yield tear and dart drop property advantages over Nylon 6 films

• Nylon 66 copolymer based BOPA Films exhibited superior puncture performance than Nylon 6 BOPA films while maintaining most other film properties

• Al foil laminate containing Nylon 66 copolymer BOPA Film gave 35-45% increase over the Control Bag laminate containing Nylon 6 BOPA Film

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Acknowledgements

Tricia BowenZach CarbenJohn TriaMike GoodinLisa Goldstein Ed NerlichSteve Manning

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Questions?