Long Fiber-Reinforced Propylene Composition for Use in a Thin Part

Abstract

A fiber-reinforced polymer composition that comprises a polymer matrix that contains a propylene polymer is provided. The polymer matrix constitutes from about 30 wt. % to about 80 wt. % of the composition, and a plurality of long reinforcing fibers that are distributed within the polymer matrix. The fibers constitute from about 20 wt. % to about 70 wt. % of the composition. The polymer composition exhibits a spiral flow length of about 450 millimeters or more as determined in accordance with ASTM D3121-09, and after aging at a temperature of 150° C. for 1,000 hours, a Charpy unnotched impact strength greater than about 15 kJ/m 2 as determined at a temperature of 23° C. in accordance with ISO Test No. 179-1:2010.

What is claimed is: 
     
         1 . A fiber-reinforced polymer composition comprising:
 a polymer matrix that contains a propylene polymer, wherein the polymer matrix constitutes from about 30 wt. % to about 80 wt. % of the composition; and   a plurality of long reinforcing fibers that are distributed within the polymer matrix, wherein the fibers constitute from about 20 wt. % to about 70 wt. % of the composition, wherein the polymer composition exhibits a spiral flow length of about 450 millimeters or more as determined in accordance with ASTM D3121-09, and further wherein after being aged at 150° C. for 1,000 hours, the composition exhibits a Charpy unnotched impact strength greater than about 15 kJ/m 2  as determined at a temperature of 23° C. in accordance with ISO Test No. 179-1:201.   
     
     
         2 . The fiber-reinforced polymer composition of  claim 1 , wherein the propylene polymer has a melt flow index of about 150 grams per 10 minutes or more as determined in accordance with ISO 1133-1:2011 at a load of 2.16 kg. 
     
     
         3 . The fiber-reinforced polymer composition of  claim 1 , wherein the propylene polymer has a melt flow index of about 180 grams per 10 minutes or more as determined in accordance with ISO 1133-1:2011 at a load of 2.16 kg and temperature of 230° C. 
     
     
         4 . The fiber-reinforced polymer composition of  claim 1 , wherein the fibers have a median length of about 1 millimeter or more and constitute from about 20 wt. % to about 70 wt. % of the composition. 
     
     
         5 . The fiber-reinforced polymer composition of  claim 1 , wherein the polymer matrix contains a propylene homopolymer, propylene/α-olefin copolymer, or a combination thereof. 
     
     
         6 . The fiber-reinforced polymer composition of  claim 1 , wherein the composition is formed by a process that includes melt blending a propylene polymer with a chain-scission agent to form a high flow propylene polymer having a melt flow index of about 150 grams per 10 minutes or more as determined in accordance with ISO 1133-1:2011 at a load of 2.16 kg and temperature of 230° C., extruding the high flow propylene polymer through an impregnation die, and pulling a plurality of fibers through the impregnation die for contact with the polymer to form the fiber-reinforced composition. 
     
     
         7 . The fiber-reinforced polymer composition of  claim 6 , wherein the chain-scission agent includes an organic peroxide. 
     
     
         8 . The fiber-reinforced polymer composition of  claim 6 , wherein the chain-scission agent is present in an amount of from about 0.001 wt. % to about 0.5 wt. %, based on weight of the propylene polymer. 
     
     
         9 . The fiber-reinforced polymer composition of  claim 6 , wherein the composition comprises an additional propylene polymer that is blended with the fiber-reinforced composition. 
     
     
         10 . The fiber-reinforced polymer composition of  claim 1 , wherein the fibers are glass fibers. 
     
     
         11 . The fiber-reinforced polymer composition of  claim 1 , wherein the fibers are oriented in a longitudinal direction of the composition. 
     
     
         12 . The fiber-reinforced polymer composition of  claim 1 , wherein the composition exhibits a Charpy unnotched impact strength greater than about 15 kJ/m 2  as determined at a temperature of −30° C. in accordance with ISO Test No. 179-1:2010. 
     
     
         13 . The fiber-reinforced polymer composition of  claim 1 , wherein the ratio of the Charpy unnotched impact strength after aging to the Charpy unnotched impact strength prior to aging is about 0.6 or more. 
     
     
         14 . The fiber-reinforced polymer composition of  claim 1 , wherein the composition exhibits a tensile strength of from about 20 to about 300 MPa, a tensile break strain of about 0.5% or more, and/or a tensile modulus of from about 3,500 MPa to about 20,000 MPa, as determined in accordance with ISO Test No. 527-1:2012 at 23° C. 
     
     
         15 . The fiber-reinforced polymer composition of  claim 1 , wherein after aging at a temperature of 150° C. for 1,000 hours, the composition exhibits a tensile strength of from about 20 to about 300 MPa as determined at a temperature of 23° C. in accordance with ISO Test No. 527-1:2012. 
     
     
         16 . The fiber-reinforced polymer composition of  claim 1 , wherein the composition exhibits a flexural strength of from about 50 to about 500 MPa and/or a flexural modulus of from about 2000 MPa to about 20,000 MPa, as determined in accordance with ISO Test No. 178:2010 at 23° C. 
     
     
         17 . The fiber-reinforced polymer composition of  claim 1 , wherein after aging at a temperature of 150° C. for 1,000 hours, the composition exhibits a flexural strength of from about 50 to about 500 MPa as determined at a temperature of 23° C. in accordance with ISO Test No. 178:2010. 
     
     
         18 . The fiber-reinforced polymer composition of  claim 17 , wherein the ratio of the flexural strength of the part after aging to the flexural strength prior to aging is about 0.6 or more. 
     
     
         19 . A shaped part having a wall thickness of about 2 millimeters or less that comprises the fiber-reinforced composition of  claim 1 . 
     
     
         20 . The shaped part of  claim 19 , wherein the part is injection molded. 
     
     
         21 . The shaped part of  claim 20 , wherein the part is formed with an injection pressure of about 750 bar or less. 
     
     
         22 . An automotive part comprising the fiber-reinforced polymer composition of  claim 1 . 
     
     
         23 . The automotive part of  claim 22 , wherein the automotive part is an exterior automotive part. 
     
     
         24 . The automotive part of  claim 23 , wherein the exterior automotive part is a fan shroud, sunroof system, door panel, front end module, side body panel, underbody shield, bumper panel, cladding, cowl, spray nozzle body, capturing hose assembly, pillar cover, rocker panel, or a combination thereof. 
     
     
         25 . The automotive part of  claim 22 , wherein the part is an interior automotive part. 
     
     
         26 . The automotive part of  claim 25 , wherein the part is a pedal module, instrument panel, arm rest, console, seat structure, interior module, lift gate, interior organizer, step assist, ash tray, glove box, gear shift lever, or a combination thereof.