Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1998-10-19
2001-04-03
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S501000, C524S502000, C524S507000
Reexamination Certificate
active
06211280
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to reinforcements for composites and, more specifically, to sized fiber strands having a secondary coating including polyurethane and an acrylic polymer prepared by vinyl addition polymerization of a monomer of acrylic acid, methacrylic acid or a mixture thereof, which provides an inexpensive reinforcement for polymeric matrices such as nylon.
BACKGROUND OF THE INVENTION
Reinforced composites are rapidly growing in popularity for such applications as automobile components, boat hulls and fishing rods. Reinforced polymeric composites can be formed from a polymeric matrix material, reinforcing material and any other desired components in a variety of ways. For example, for a thermosetting matrix material, a composite can be formed by molding, pultrusion, filament winding, hand lay-up or spray-up. For a thermoplastic matrix material, suitable methods for forming a composite include direct molding or extrusion compounding followed by injection molding.
As molding processes become more sophisticated and raw material costs escalate, the need for an inexpensive reinforcement which provides adequate physical properties in a composite, such as strength, modulus and impact resistance, has become increasingly important.
The coating on the reinforcement provides an interface between the reinforcement material, such as glass fiber strand, and the polymeric matrix material of the composite. The compatibility of the coating with the reinforcement material and the polymeric matrix material and strength of the bonding at the interface are important considerations in the selection of coating components. The amounts and types of components used in the coating composition influence the cost of the reinforcement. It is desirable to include less expensive components in the coating composition to lessen cost while maintaining performance of the reinforcement in the composite.
U.S. Pat. No. 4,762,750 discloses sized fiber bundles coated with an impregnating composition having one or more elastomeric polymers that are essentially free of hydrocarbon diene and chlorine functionalities and one or more crosslinking materials (see Abstract). The elastomeric polymer can be a polyurethane or an ethylene-containing interpolymer formed from ethylene monomer and one or more polar comonomers. See column 6, lines 21-38.
U.S. Pat. No. 5,182,784 discloses an aqueous coating composition for glass strands consisting essentially of 2-50 weight percent of a thermoplastic polyurethane latex, 3-55 weight percent of a first curable acrylic latex and 0.5-10 weight percent of a paraffin wax emulsion or a second curable acrylic latex. See column 1, lines 29-39.
In reinforcement of composites, including thermoplastics such as nylon, it is desirable to simplify and diversify the coating process and reduce the cost of coating composition components while providing coated reinforcements which have acceptable physical performance in the composite.
SUMMARY OF THE INVENTION
The present invention provides an aqueous coating composition adapted to coat a sized fiber strand, the aqueous coating composition comprising: (a) a urethane-containing polymer; and (b) a polymer prepared by addition polymerization of a monomer selected from the group consisting of acrylic acid, methacrylic acid and a mixture thereof, the aqueous coating composition being essentially free of acrylic latex, the aqueous coating composition being different from a sizing composition coating the sized fiber strand.
Another aspect of the present invention is an aqueous coating composition adapted to coat a sized fiber strand, the aqueous coating composition comprising: (a) a urethane-containing polymer; and (b) a polymer prepared by addition polymerization of (1) a monomer selected from the group consisting of acrylic acid, methacrylic acid and a mixture thereof; and (2) an addition polymerizable unsaturated carboxylic acid adapted to form a polymer, the aqueous coating composition being essentially free of acrylic latex, the aqueous coating composition being different from a sizing composition coating the sized fiber strand.
Another aspect of the present invention is a fiber strand adapted to reinforce a polymeric matrix material, at least a portion of a surface of the fiber strand having applied thereto a primary coating of a sizing composition and thereupon an aqueous secondary coating composition, the aqueous secondary coating composition comprising: (a) a urethane-containing polymer; and (b) a polymer prepared by addition polymerization of a monomer selected from the group consisting of acrylic acid, methacrylic acid and a mixture thereof, the aqueous coating composition being essentially free of acrylic latex, the aqueous coating composition being different from the sizing composition.
Yet another aspect of the present invention is a fiber strand adapted to reinforce a polymeric matrix material, at least a portion of a surface of the fiber strand having applied thereto a primary coating of a sizing composition and thereupon an aqueous secondary coating composition, the aqueous secondary coating composition comprising: (a) a urethane-containing polymer; and (b) a polymer prepared by addition polymerization of (1) a monomer selected from the group consisting of acrylic acid, methacrylic acid and a mixture thereof; and (2) an addition polymerizable unsaturated carboxylic acid adapted to form a polymer with the monomer, the aqueous coating composition being essentially free of acrylic latex, the aqueous coating composition being different from the sizing composition.
Another aspect of the present invention is a reinforced polymeric composite comprising: (a) a fiber strand reinforcing material, at least a portion of a surface of the fiber strand reinforcing material having applied thereto a primary coating of a sizing composition and thereupon an aqueous secondary coating composition, the aqueous secondary coating composition comprising: (1) a urethane-containing polymer; and (2) a polymer prepared by addition polymerization of a monomer selected from the group consisting of acrylic acid, methacrylic acid and a mixture thereof, the aqueous coating composition being essentially free of acrylic latex, the aqueous coating composition being different from the sizing composition; and (b) a polymeric matrix material.
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patent: 5393379 (1995-02-01), Parrinello
patent: 5437928 (1995-08-01), Thimons et al.
K. Loewenstein,The Manufacturing Technology of Continuous Glass Fibres, (3d Rev. Ed. 1993), pp. 165-172, 219-222, 237-289.
K. Loewenstein,The Manufacturing Technology of Continous Glass Fibres, (2d Ed. 1983), pp. 29, 33-45, 47-60, 118-120, 122-125.
Handbook of Plastic Materials and Technology, vol. 79, “Reinforced Plastics, Filament Winding” by A. M. Shibley, pp. 955-1062.
Handbook of Plastics Materials and Technology, vol. 89, “Extrusion”, by Christiaan Rauwendaal, pp.1179-1215.
Handbook of Plastic Materials and Technology, vol. 89, “Injection Molding (IM)” by I. I. Rubin, pp. 1225-1271.
Cain Edward J.
PPG Industries Ohio Inc.
Siminerio Andrew C.
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