Continuous filament mat and method of making

Abstract

The present invention provides an improved method of forming continuous filament mat (CFM) at greater through-put while maintaining or improving product quality by use of a synchronized draw process. The synchronized draw process provides CFM having improved weight variation, structure and tensile strength is capable of operating at increased mat line speed. CFM produced may have controlled mat density, MD density variation, CM density variation, MD tensile strength and CM tensile strength by controlling the period, frequency and interval of the deposited fiber strands. Using the synchronization technology of the present invention it is possible to control the tensile strength ratio (MD / CD) to meet a specific customer need by adjusting the LFR, frequency, period, and line speed. The method of the present invention provides for increasing the throughput of specialized and costly CFM manufacturing equipment without substantial expenditure.

Description

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION [0001] The present invention relates to an improved continuous filament mat (CFM) having improved weight variation along the length of the mat and a method of making such a mat. BACKGROUND OF THE INVENTION [0002] Continuous Filament Mat (CFM) is a continuous reinforcement fiber, non-woven mat containing a resin compatible binder. CFM is used with polyester, vinyl esters urethanes and other compatible resin systems. It includes continuous fibers randomly oriented in multiple layers with a suitable bonding resin and typically contains a silane coupling agent. CFM is particularly suitable for compression molded electrical and non-electrical laminates, as well as for use in pultrusion processes or any process in which a smooth surface is desired. CFM is used in many fiberglass reinforced plastic (FRP) structural applications such as: compression molding, infusion molding, filament winding, pultrusion, reaction injection moldi...

AI Technical Summary

Benefits of technology

[0014] The present invention provides an improved method of forming continuous filament mat at greater through-put while maintaining or improving product quality by use of a synchronized draw process. The synchronized draw process provides CFM having improved weight variation is capable of operating at increased mat line speed (Sml) and provides CFM having improved structure and tensile strength.

[0015] The synchronized draw process may be performed on a standard CFM line with little additional hardware and hence at low cost. The additions to the CFM line include a master PLC 50 that is in communication with forming position 12 via PLC linkage 52. The synchronized draw process may also include a master encoder 54 downstream from the forming position 12 to provide conveyor speed and position data to the master PLC 50 so that the forming position 12 may be individually controlled.

Problems solved by technology

The molding pressure is typically lower in RTM than in the compression molding process, therefore, tooling and equipment capital costs are lower than high volume compression molding, but higher than open molding processes.

In the prior art processes, a period in excess of about 180 mm causes a standard deviation of the weight of the mat in the machine direction to increase above about 2.2, which a variation that is not acceptable for use in a number of composite fabrication processes.

This variation in weight is increased when fiber draw positions are taken off-line due to equipment failures or for maintenance.

The limitations on frequency (f), LFR and mat line speed (Sml) prevent the prior art CFM process from producing mat having a suitable tensile strength at commercially desirable high speeds.

The increased melting capacity has created a bottleneck in the production line at the CFM line.

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