JFE No. 4 20045 p 82 Composite Material for Automotive Headliners Expandable Stampable Sheet with Light Weight and High Stiffness A JFE SUZU JFE HA KP 50 mass 30 UL 800 g/m 2 7.2 N/mm Abstract: KP-Sheet is a stampable sheet made of glass fi ber and polypropylene and has distinct characteristics of expansion in thickness. For the development of lightweight and high stiffness KP-Sheet, glass fi ber content and glass fi ber arrangement in thickness direction were studied in order to increase the expansivity. Although the expansivity increased with an increase of glass fi ber content and the elastic slope was enhanced due to an increase in the thickness, the value of the maximum elastic slope was saturated at over 50 mass% of the glass fi ber content. By controlling the glass fi ber arrangement in the thickness direction, the spring back of glass fi bers was enhanced and the expansivity increased more than 30% at the same unit weight. A newly developed UL-grade improved the elastic slope, which was enhanced to 7.2 N/mm at a unit weight of web 800 g/m 2 and is able to reduce further the weight of the parts while holding superior moldability and dimensional stability equal to those of the normal grade. 1. JFE GFPP K Photo 1 1997 KP-sheet Headliner Structure of expanded KP-sheet 100 µm Photo 1 Headliner made of KP-sheet KP GF PP 77
GF GF 3 1,2) 1 2 3 4 KP PP KP Photo 1 GF PP GF PP 3) KP ULultra-light 2.KP 2.1KP KP Fig. 1 PET GF PP 4) 2.2KP KP GF 2 3 KP Olefin film Stampable sheet consisting of GF and PP PET scrim Fig. 1 Schematic illustration of KP-sheet for automotive headliner GF KP KP PP GF KP PP KP 2 4 5) 1 2.3 E 2 I EI 2 GF KP 2 KP PP Fig. 2 PP GF PP PP GF PP GF GF KP P PP GF GF Fig. 3 GF 2 I w A n h 3 /12 w h AGF 2 n GF JFE No. 4 2004 5 78
GF Powdered PP GF Melted PP Surface texture Press Heated to melt PP Molded Web KP-sheet (Consolidated sheet) Freely expanded KP-sheet Solid PP Expansion-molded KP-sheet Manufacturing process Expansion molding process Fig. 2 Change in distribution of PP in manufacturing and expansion molding processes G W/(l w) G: Unit weight of expanded article W: Weight of expanded article PP l 3. h GF 3.1KP A n GF A n (GC/h)/ / / G 2 CGF 3 GF PP GF GF EI 2 I 2 EI 2 EI (wc/ ) G h 2 KP GF W Fig. 3 Schematic model of expanded article of KP-sheet 25 mm GF PP 250 250 mm 180 635 800 g/m 2 GF 45, 50, 55, 60 mass PET 205 0.3 MPa 15 s GF 3.2 2 KP 200 5 mm 3.5 mm 5 mm 5 mm 3.3 l 150 w 50 mm 50 mm/min 100 79 JFE No. 4 2004 5
- 3.4 GFX PP 4. 4.1 Fig. 4 635 g/m 2 GF GF GF 45 massgf 2.8 mm 4 N/mm GF 50 mass 3.4 mm 5.5 N/mm 55 mass GF GF 50 mass GF 50 mass 700 g/m 2 Fig. 5 635 g/m 2 GF 2 GF 2 635 2 700 g/m 2 2 700 g/m 2 6.0 GF content: 45 mass% Freely expanded Expansion molded 50 mass% 55 mass% 1.0 2.5 3.5 Expansion molded thickness(mm) 60 mass% Fig. 4 Effect of GF content and expansion molded thickness on elastic slope (Unit weight of web: 635 g/m 2 ) 9 8 7 6 5 4 3 2 1 0 0 1 000 2 000 3 000 4 000 5 000 6 000 7 000 (Unit wight of GF) (Square of molded thickness) (g/m 2 mm 2 ) 800 g/m 2 GF 2 Fig. 6 Fig. 5 Fig. 6 GF 2 GF GF 2 Fig. 4 50 mass GF 50 mass GF 50 mass GF 635 g/m 2 700 g/m 2 Fig. 5 Effect of the product of square of expansion molded thickness and unit weight of GF on elastic slope (GF content: 50 mass%) 14 12 10 8 6 4 2.9 45 mass% 50 mass% 55mass% 60 mass% 4.6 4.4 4.7 800 g/m 2 3.7 4.1 4.3 750 g/m 2 4.4 3.5 3.8 700 g/m 2 3.5 3.7 3.2 650 g/m 2 3.4 3.6 635 g/m 2 2 0 2 000 4 000 6 000 8 000 10 000 12 000 14000 (Unit weight of GF ) (Spuare of molded thickness)(g/m 2 mm 2 ) 4.2GF 3.9 Fig. 6 Relationship between Elastic slope and the product of unit weight of GF and square molded thickness Fig. 7 GF PP θ GF Fig. 8 JFE No. 4 2004 5 80
Accumulating angle:θ Web Slurry Moving derection of the forming belt Fig. 7 Schematic diagram of the paper-making machine Elastic slope (N/mm) Restricted Free Free expansion thickness (mm) 7.0 6.0 Controlled GF arrangement Normal grade 1.0 1.5 2.5 3.5 Expansion molded thickness (mm) Fig. 9 Comparison in elastic slope between restricted and free expansions (Unit weight of web: 800 g/m 2, GF50 mass% Web: Controlled GF arrangement) 1.0 500 600 700 800 900 1 000 1 100 Unit weight of web(g/m 2 ) Consolidated sheet Fig. 8 Comparison in free expansion thickness between controlled GF arrangement and normal grade PP Controlled GF arrangement Normal grade 30 GF 900 g/m 2 X Photo 2 GF 3 4.3 5 mm Photo 2 GF arrangement in thickness direction of expanded KP-sheet (Unit weight of web: 900 g/m 2 ) 800 g/m 2 G 50 Fig. 9 3.6 mm 2.9 mm 2.9 mm 3.4 N/mm 4 N/mm Restricted expansion 4 N/mm 4.5 N/mm 3 GF 3.5 N/mm PP Photo 3 PP PP PP GF PP GF PP PP PP Free expansion 1 mm Photo 3 Distribution of PP in expansion-molded articles KP GF 81 JFE No. 4 2004 5
10.0 8.0 6.0 500 2.9 GF GF PP UL 4.4UL GF 50 mass GF UL Fig. 10 50 20 UL UL grade 3.3 2.6 3.5 2.8 Number:Molded thickness(mm) 3.2 4.4 3.6 600 700 800 900 1 000 1 100 Unit weight of web (g/m 2 ) Normal grade Fig. 10 Comparison in elastic slope between UL grade and normal grade GF PP KP KP UL 30 2 50 20 1 Haque, E. et al. Development of low density glass mat thermoplastic composites for headliner applications. SAE Technical Paper Series. SAE 2000 World Cong. Detroit (USA). Paper no. 2000-01-1129, 2000. 2 KP KP vol. 29 230. 3 vol. 29no. 41997p. 196 201 4 KP K p. 124 5 Araki, Y. et al. Development of lightweight and high stiffness New KP-Sheet for automotive headliners by controlling of glass fi ber arrangement. Pro. of the 7th Jan. Int. SAMPE Symp. Tokyo Big Sight (Japan), vol. 11, 2001, p. 407. 5. JFE No. 4 2004 5 82