Glass fiber strand mats, thermosetting composites reinforced with the same and methods for making the same

A reinforced polymeric composite comprising:

• (a) a thermosetting matrix material;
• and
• (b) a reinforcing mat comprising:
• (1) a primary, supporting layer comprising a plurality of randomly oriented essentially continuous glass fiber strands coated with a sizing composition on at least a portion of surfaces thereof, the sizing composition comprising a thermosetting film-forming material which is compatible with the thermosetting matrix material, the primary layer comprising about 1 to about 20 weight percent of the mat on a total solids basis;
• and
• (2) a secondary layer positioned upon and supported by a surface of the primary layer, the secondary layer comprising a plurality of glass fiber strands coated with a second sizing composition on at least a portion of surfaces thereof, the second sizing composition comprising a thermosetting film-forming material which is compatible with the thermosetting matrix material, the mean average length of the glass fiber strands of the secondary layer ranging from about 20 to about 125 millimeters, wherein the strands of the primary layer are entangled with the strands of the secondary layer by needling the primary layer and the secondary layer together and the mat has a surface weight ranging from about 300 to about 3060 grams per square meter.

A method for making a mat adapted to reinforce a thermosetting matrix material to form a reinforced composite, the method comprising the steps of:

• (a) dispersing a plurality of essentially continuous glass fiber strands to form a primary, support layer, the glass fiber strands being coated with a sizing composition on at least a portion of surfaces thereof, the sizing composition comprising a thermosetting film-forming material which is compatible with the thermosetting matrix material, the primary layer comprising about 1 to about 20 weight percent of the mat on a total solids basis, such that the glass fiber strands of the primary layer are randomly oriented;
• and
• (b) dispersing a plurality of chopped glass fiber strands upon a surface of the primary layer, the mean average length of the chopped glass fiber strands ranging from about 20 to about 125 millimeters, the chopped glass fiber strands being coated with a second sizing composition on at least a portion of surfaces thereof, the second sizing composition comprising a thermosetting film-forming material which is compatible with the thermosetting matrix material;
• and
• (c) entangling the essentially continuous glass fiber strands of the primary layer with the chopped glass fiber strands of the secondary layer by needling the layers together to form a mat, the mat having a surface weight ranging from about 300 to about 3060 grams per square meter.

A method for reinforcing a thermosetting matrix material to form a reinforced composite, the method comprising the steps of:

• (a) dispersing a plurality of essentially continuous glass fiber strands to form a primary, support layer, such that the glass fiber strands of the primary layer are randomly oriented the glass fiber strands being coated with a sizing composition on at least a portion of surfaces thereof, the sizing composition comprising a thermosetting film-forming material which is compatible with the thermosetting matrix material, the primary layer comprising about 1 to about 20 weight percent of the mat on a total solids basis;
• and
• (b) dispersing a plurality of chopped glass fiber strands upon a surface of the primary layer, the mean average length of the chopped glass fiber strands ranging from about 20 to about 125 millimeters, the chopped glass fiber strands being coated with a second sizing composition on at least a portion of surfaces thereof, the second sizing composition comprising a thermosetting film-forming material which is compatible with the thermosetting matrix material;
• (c) entangling the essentially continuous glass fiber strands of the primary layer with the chopped glass fiber strands of the secondary layer by needling the layers together to form a mat, the mat having a surface weight ranging from about 300 to about 3060 grams per square meter;
• (d) coating and impregnating at least a portion of the mat with a thermosetting matrix material;
• and
• (e) at least partially curing the thermosetting matrix material to form a reinforced composite.