Chopped glass strand mat and method of producing same

#1. Field of the Invention

#The present invention relates to a chopped glass strand mat and a method of producing the mat.

#2. Background Art

#FIG. 1 is a schematic representation of a process used to produce a glass strand mat in accordance with the present invention.

#The schematic representation shown in FIG. 1 illustrates one method of producing a glass strand mat 10 in accordance with the present invention. The production system 12 includes a first chopper 14 into which glass rovings are fed. The glass rovings comprise individual glass strands, or filaments, arranged generally parallel to one another in a large group. The glass rovings are chopped into filaments 16 by the first chopper 14. It should be noted that a typical chopping process does not completely reduce a roving into individual filaments. Rather, chopping a roving usually results in a combination of filaments (individual glass strands) and bundles (filaments arranged generally parallel to one another in small groups). Therefore, except as specifically noted, the term “filaments” includes individual filaments, bundles, or a combination thereof.

#After the rovings are chopped in the first chopper 14, the glass filaments 16 are then distributed in a first layer 18 onto a first surface 20 of a first moving belt 22. The first moving belt 22 is made from, or at least the first surface 20 is coated with, a non-stick material such as Teflon®. The reason for using a nonstick surface becomes clear as the process proceeds. The glass filaments 16 are distributed approximately uniformly in a first distribution density onto the first surface 20 of the first moving belt 22. This helps to ensure that the glass mat 10 will have uniform properties, which also helps to ensure a similar uniformity in any composite material that utilizes the glass mat 10.

#The distribution of the glass filaments 16 in the first layer 18 is controlled by a number of parameters which help determine not only the distribution density, but also the degree of uniformity of the distribution. For example, the rate at which the glass filaments 16 leave the first chopper 14, and the speed of the first moving belt 22, both affect the distribution density of the glass filaments 16. In addition, holding constant the rate at which the glass filaments 16 leave the first chopper 14 helps to ensure that the glass filaments 16 are distributed uniformly. Similarly, keeping the speed of the first moving belt 22 constant, also helps to ensure a uniform distribution of the glass filaments 16.