Thermoplastic towpreg offers advantages over thermoset prepregs including improved performance, processability and lower cost. However, the composites industry has long used thermoset composites due to extensive experience. FibrFlex3D is a new multidirectional thermoplastic towpreg that combines continuous fiber reinforcement with chopped fiber in the matrix. This provides tougher composites that can be more easily processed while eliminating the need for machining or bonding parts. Initial test results show properties comparable to baseline while improving impact resistance and features like molded-in inserts. Further optimization is underway to utilize different resins and fibers like carbon fiber.

2. Advances in Multidirectional
Thermoplastic Towpreg
Michael R. Favaloro, CompositeTechs
Robert Davies, Fibrtec
Mingfu Zhang, Johns Manville Fiberglass

3. Content
• Introduction
– Why thermoplastic v's thermoset prepregs
– Manufacturing processes for continuous fiber TP
prepreg
– FibrFlex3D product and process description
• Product Development Results
• Discussion
• Summary and Conclusions

4. Introduction
Why Thermoplastic Prepreg?
• Thermoplastic Composites Provide Significant
Advantages v's Thermosets
– Improved Performance, Processability and Cost
• However, the Composites Industry is committed
to Thermoset Composites
– >50 years experience
– Tech depth, capital equipment, and database is
extensive, as well as resistance to change
• The Use of Thermoplastics Have Begun to
Accelerate Industry Uptake
– Lower cost materials and processes lead to adoption

5. Introduction
Continuous Fiber TP Prepreg Processes
• Most TP Prepreg Processes Require Conversion of Resin
to Solution, Powder, Film or Fiber, which adds cost
Source: Wakeman, M.D., Månson, J-AE, Design and Manufacture of Textile Composites, Chapter 6, 2005.
• The FibrFlex Process Utilizes
Thermoplastic Resin Pellets as Supplied
– No Resin Conversion = low cost
– No Tape Slitting, further reducing cost
– Straight Line, Simple Process
The FibrFlex TP Prepreg results in a 20%+
savings in product cost

6. Introduction
FibrFlex3D Process Description
• Simple Process + Low CAPEX = Low Cost Product
• Tailorable for many resin/fiber/chopped fiber combinations
• Allows for rapid product development
• Other fillers can also be incorporated

7. Introduction
FibrFlex3D* Product Description
• FibrFlex3D Combines Continuous Fiber & Chopped
Fiber Reinforcement with a Thermoplastic Matrix
• The net result is a
– Tougher composite
– More conformable, ease of processing
– Chopped Fiber reinforces bosses and smaller features that
are formed in the final molding process
• Combines Continuous Reinforcement and Injection Molded
features
• Eliminates machining/bonding of bosses and other features while
still incorporating reinforcement in those areas
* Patent pending

8. Introduction
FibrFlex3D Product Description (cont’d)
• Continuous reinforcement is carbon, glass, basalt, etc.
• Most thermoplastic matrices can be used
• The matrix can Incorporate chopped fiber, particulates,
nanofibers, etc.
• Unsaturated core provides flexibility, ease of handling
– The end product is easily consolidated to a void free laminate
Continuous Reinforcement
Resin/Chopped Fiber
Unsaturated Tow

9. Introduction
FibrFlex3D Product Description (cont’d)
• Short reinforcement improves interlaminar, toughness, and
interface with continuous fiber
• Short reinforcement also flow into bosses, molded features
• Other particulates can replace short reinforcement as appropriate
– Electrical Enhancement
– Density Management
– Etc
Continuous Fiber
Chopped Fiber

10. Introduction
FibrFlex3D Product Description (cont’d)
Tow surface

11. Introduction
FibrFlex3D Product Description (cont’d)
Burn off oven results

12. Product Development Results
Material vol % wt %
Density
(g/cc)
PPS 49.6 34.6 1.35
E Glass,
1200 tex 47 61 2.51
E Glass
chopped 3.43 4.4 2.51
FibrFlex3D measured 1.935
calculated 1.935
• PPS E-Glass FibrFlex3D Components
Have Been Fabricated
Final Part Porosity is Negligible
Wet Out is Excellent, Debulk is Complete

13. Results (continued)
• Chopped
Fiber/Matrix
Successfully
Formed the
Threads in this
G/PPS
FibrFlex3D
Commercial
Application

14. Molded-In Inserts

15. Preliminary Mechanical Property Data
Several versions of Toray PPS resin were evaluated
Test data courtesy of Johns Manville Fiberglass
0-90 Data
Baseline
Panel# 1B-1 2B-1 3B-1 4B-1 5B-1 150813-01
Continuous Fiber Wt % 64.7 64.4 62.4 62.7 63.5 67.7
Chopped Glass % by wt 1.2 2.2 3.5 3.1 3.4 3.6
Base resin melt flow rate 410 410 410 1090 1850 very low
Flex Strength mPa 536 333 426 363 339 647
Modulus gPa 20.4 11.8 15.1 12.2 11.5 28.4
Strain % 2.74 3.15 3.06 3.20 3.24 2.4
Tensile Strength mPa 395 256 352 266 261 328
Modulus mPa 30400 17800 23700 27300 23100 5330
Strain % 1.54 1.78 1.69 1.43 1.44 7.4
Interlamianr Shear mPa 33.5 156.9 75.0 33.5 83.5 183
Unnotched Charpy
kJ/m
2 59.4 67.1 67.3 51.4 48.9 43.1
Continuous Fiber Vol % 49.1 49.1 47.3 47.5 48.15 53

16. Mechanical Results Discussion
• Incorporation of Chopped Fiber Reduces Continuous FV,
which Reduces Some Properties, BUT
– Molded In Features Are Stronger with as-molded, un-cut reinforcement v’s
bonded or machined features.
• Correlations
– Chopped Glass seems to improve interlaminar shear and Charpy impact
– Tensile and Flex appear higher with higher viscosity resin, and with lower
chopped glass content
– Test panel fabrication with FibrFlex3D resulted in quality laminates with
good flow.
• Follow on work is in process to address comparisons of
– Same Resin Source and MW
– Same Continuous FV
– Carbon Fiber Reinforced Property Data

17. Summary and Conclusions
• FibrFlex3D is a Patent Pending enabling
material that allows for low cost co-
molding of Continuous Fiber and Discrete
Thermoplastic Composites
– No substantial drop-off of continuous
properties
– Improved performance in reinforced features
• Future work will Investigate carbon fiber
chopped filler as well as all carbon
composites

18. Special Thanks to
• Toray – PPS Resin Support
• Johns Manville – Reinforcement and
Testing Support
• CompositeTechs LLC – Technical Support

19. Thank You
• For More Information Contact
Bob Davies, Fibrtec
903-280-7199
bob@fibrtec.com
Mike Favaloro, CompositeTechs
978-270-6011
mikef@compositetechs.com