Method of making a reinforcing mat for a pultruded part

A reinforcing structure adapted for use in the manufacture of a pultruded part where the reinforcing structure is pulled through a pultrusion die in a continuous longitudinal pull direction during pultrusion, the reinforcing structure comprising:

• a plurality of first reinforcing fibers at an angle relative to the longitudinal pull direction during pultrusion, the first reinforcing fibers being in a generally planar, non-overlapping configuration, wherein each of the plurality of first reinforcing fibers has a cross-sectional profile;
• a plurality of second reinforcing fibers at an angle relative to the longitudinal pull direction during pultrusion that is different than the angle of the first reinforcing fibers, the second reinforcing fibers being in a generally planar, non-overlapping configuration, wherein each of the plurality of second reinforcing fibers has a cross-sectional profile that is smaller than the cross-sectional profile of each of the plurality of first reinforcing fibers;
• and
• a permeable transport web of staple fibers having a weight of about 10 grams per square meter to about 1200 grams per square meter attached to the first reinforcing fibers and the second reinforcing fibers to provide longitudinal strength, shear strength, and anti-skew properties sufficient to substantially maintain the relative orientation of the first and second reinforcing fibers when subjected to pulling forces encountered during pultrusion,
• the reinforcing structure having a transverse tensile strength in a direction transverse to the longitudinal pull direction and a parallel tensile strength in a direction parallel to the longitudinal pull direction, the transverse tensile strength being substantially greater than the parallel tensile strength.

A reinforcing structure adapted for use in the manufacture of a pultruded part where the reinforcing structure is pulled through a pultrusion die in a continuous longitudinal pull direction during pultrusion, the reinforcing structure comprising:

• a first reinforcing layer comprising a plurality of first reinforcing fibers each having a cross-sectional profile and each arranged in a generally planar, non-overlapping configuration, the first reinforcing fibers attached to a permeable transport web of staple fibers to provide shear strength and anti-skew properties sufficient to substantially maintain the relative orientations of the first reinforcing fibers when subjected to pulling forces encountered during pultrusion;
• a second reinforcing layer comprising a plurality of second reinforcing fibers each having a cross-sectional profile that is larger than the cross-sectional profile of the first reinforcing fibers, the second reinforcing fibers arranged in a generally planar, non-overlapping configuration, the second reinforcing fibers attached to a permeable transport web of staple fibers to provide shear strength and anti-skew properties sufficient to substantially maintain the relative orientations of the second reinforcing fibers when subjected to pulling forces encountered during pultrusion;
• and
• a plurality of longitudinal rovings positioned between the first and second reinforcing layers,
• wherein the reinforcing structure has a transverse tensile strength in a direction transverse to the longitudinal pull direction and a parallel tensile strength in a direction parallel to the longitudinal pull direction, and wherein the transverse tensile strength is substantially greater than the parallel tensile strength.

A method of preparing a reinforcing structure for use in the manufacture of a pultruded part, where the reinforcing structure is pulled through a pultrusion die in a continuous longitudinal direction during pultrusion, the method comprising:

• arranging a plurality of first reinforcing fibers generally transverse to the longitudinal pull direction, wherein each of the plurality of first reinforcing fibers has a cross-sectional profile;
• arranging a plurality of second reinforcing fibers generally parallel to the longitudinal pull direction wherein each of the plurality of second reinforcing fibers has a cross-sectional profile that is smaller than the cross-sectional profile of each of the plurality of first reinforcing fibers;
• contacting the first reinforcing fibers with a permeable transport web of staple fibers that comprise a plurality of first polymeric fibers having a first glass transition temperature and a plurality of second polymeric fibers having a second glass transition temperature;
• and
• attaching the first reinforcing fibers to the transport web by randomly entangling at least a portion of the staple fibers with the first reinforcing fibers, wherein the reinforcing structure has a transverse tensile strength in a direction transverse to the longitudinal direction and a parallel tensile strength in a direction parallel to the longitudinal direction, and wherein the transverse tensile strength is substantially greater than the parallel tensile strength.

A method of preparing a reinforcing structure for use in the manufacture of a pultruded part, where the reinforcing structure is pulled through a pultrusion die in a continuous longitudinal direction during pultrusion, the method comprising:

• arranging a plurality of first reinforcing fibers at an angle relative to the longitudinal pull direction during pultrusion, the first reinforcing fibers being in a generally planar, non-overlapping configuration and each of the plurality of first reinforcing fibers having a cross-sectional profile;
• arranging a plurality of second reinforcing fibers at an angle different than the angle of the first reinforcing fibers, the second reinforcing fibers being in a generally planar, non-overlapping configuration, and each of the plurality of second reinforcing fibers having a cross-sectional profile that is smaller than the cross-sectional profile of each of the plurality of first reinforcing fibers;
• and
• contacting the first reinforcing fibers with a permeable transport web of staple fibers having a weight of about 10 grams per square meter to about 1200 grams per square meter;
• and
• attaching the first reinforcing fibers to the transport web by randomly entangling at least a portion of the staple fibers with the first reinforcing fibers, wherein the reinforcing structure has a transverse tensile strength in a direction transverse to the longitudinal direction and a parallel tensile strength in a direction parallel to the longitudinal direction, and wherein the transverse tensile strength is substantially greater than the parallel tensile strength.