Stock material or miscellaneous articles – Composite – Of polyamidoester
Reexamination Certificate
2001-08-31
2003-09-09
Seidleck, James J. (Department: 1711)
Stock material or miscellaneous articles
Composite
Of polyamidoester
C428S213000, C428S297400
Reexamination Certificate
active
06617032
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a polyurea—polyurethane composite structure that is substantially free from emission of volatile organic compounds (VOCs). The present invention more specifically relates to a composite structure having a flexural modulus of at least 200,000 lb/in
2
that is utilized in the boating, automobile, swimming pool, and bathtub industries and that includes an aliphatic first, or top, layer which is a show surface of the composite structure and is derived from polyisocyanate and a polyamine, and a second, or polyurethane-backing, layer derived from polyisocyanate and at least one polyol having a theoretical functionality of at least three. The first and second layers of the composite structure are both substantially free of VOCs.
BACKGROUND OF THE INVENTION
Use of composite structures throughout the boating, automobile, swimming pool, and bathtub industries is known in the art. Prior art composite structures typically include a first-layer of styrenated polyester. It is known in the art that, during application of the first-layer of styrenated polyester to a mold substrate, large quantities of styrene monomers, which are considered volatile organic compounds (VOCs), are emitted which is undesirable for environmental, health, and safety reasons. Furthermore, large quantities of other VOCs, such as methyl ethyl ketone, are also typically emitted during application and cross-linking of the styrenated polyester first-layers of the prior art. Emission of these other VOCs is also undesirable for environmental, health, and safety reason.
Furthermore, because the first-layer of the composite structure is a top layer or show surface of the composite structure, the composite structures of the prior art which include styrenated polyester as the first-layer, are excessively brittle and suffer from cracking and chipping defects due to this excessive brittleness characteristic of styrenated polyesters. Such defects become particularly apparent during shipping and handling, during transportation, and even during use of the composite structures. Finally, these and other composite structures of the prior art are deficient as their top layer or show surface is unstable over exposure to ultraviolet light.
Due to the inefficiencies identified in the composite structures of the prior art, it is desirable to provide a novel and durable composite structure having a top layer that does not emit VOCs during application to the mold substrate and that utilizes aliphatic components such that the top layer, or show surface, of the composite structure is stable under exposure to ultraviolet light.
SUMMARY OF THE INVENTION
According to the present invention, a composite structure is provided. The composite structure has a flexural modulus of at least 200,000 lb/in
2
such that the composite structure is tailored for use in the particular industries in which the subject invention is utilized. The composite structure includes a first-layer (A) and a second-layer (B). As understood by those skilled in the art, the first-layer is a top layer or show surface of the completed composite structure, and the second-layer is a backing layer that functions to provide support and durability to the completed composite structure.
The first-layer (A) of the composite structure is substantially free of volatile organic compounds (VOCs). As such, during application of the first-layer (A) to a mold substrate, the first-layer does not emit VOCs into the surrounding environment. Furthermore, the first-layer (A) includes aliphatic components which are ultraviolet light stable. More specifically, the first-layer (A) of the subject invention is the reaction product of a first-layer polyisocyanate component (A)(I) that includes an aliphatic polyisocyanate, and a first-layer resin component (A)(II) including a polyamine. The polyamine of the first-layer resin component (A)(II) reacts with the first-layer polyisocyanate component (A)(I) to form a polyurea first-layer. Generally, the hardness of the first-layer (A) is an important attribute throughout particular industries. The first-layer (A) is designed to have a Shore D hardness of at least 65 which is suitable for balancing durability properties of the composite structure and prevention of chipping and cracking defects like those observed in the prior art.
Like the first-layer (A), the second, or backing layer (B) of the composite structure of the subject invention is substantially free of VOCs and therefore does not emit VOCs into the surrounding environment. The second-layer (B) is the reaction product of a second-layer polyisocyanate component (B)(I) and a second-layer resin component (B)(II). The second-layer resin component (B)(II) more specifically includes at least one polyol having a theoretical functionality of at least three. In particular, there is a plurality of polyols including a first polyether polyol that is made from an initiator compound having at least three functional groups. This first polyether polyol further includes a hydroxyl number of 200 meq polyol/g KOH or more and a viscosity of 5,000 centipoise or less at 25° C. These physical properties of the first polyether polyol contribute to a second-layer (B) that provides substantial support and durability to the completed composite structure.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
A composite structure is disclosed. The composite structure of the subject invention includes a first-layer (A) and a second-layer (B). The first (A) and second (B) layers are applied to a mold substrate in an open-mold process to form the composite structure. In the open-mold process, the first-layer (A) is first applied to a surface of the mold substrate, and then the second-layer (B) is applied after the first-layer (A) without the mold substrate having to close on itself to form the composite structure. The first (A) and second (B) layers are then de-molded from the open-mold substrate.
After application of the first (A) and second (B) layers and after the de-molding of the completed composite structure, the first-layer (A) is a top layer or show surface of the composite structure whereas the second-layer (B) is a backing layer to the first-layer (A). Both the first (A) and second (B) layers of the subject invention are substantially free of volatile organic compounds (VOCs).
According to the subject invention, it is to be generally understood that substantially free of VOCs is intended to indicate that, during the production of the first (A) and second (B) layers, no significant amount, and preferably no amount, of volatile chemical compounds are emitted by the components producing such layers or the reaction mixtures thereof, where volatile chemical compounds are defined by those that contains the element carbon, excluding certain exempted compounds such as methane, carbon monoxide, carbon dioxide, carbonic acid, metallic carbides and carbonates, ammonium carbonate, and other exempt compounds. This is particularly relevant when the subject invention is compared to VOCs emitted by processes which utilize styrenated polyester compounds as reactants for the layers. This definitional standard is found under South Coast Air Quality Management District's (SCAQMD) Regulation I, Rule 102, entitled “Definition Of Terms” adopted Feb. 4, 1977 and last amended Apr. 9, 1999, and under SCAQMD's Regulation XI, Rule 1162, entitled “Polyester Resin Operations” adopted Mar. 6, 1987 and last amended Nov. 17, 2000. Under the Rule 1162 definitional standard, other exempt compounds include, but are not limited to, Group I Exempt Compounds, specifically chlorodifluoromethane (HCFC-22), dichlorotrifluoroethane (HCFC-123), tetrafluoroethane (HFC-134a), dichlorofluoroethane (HCFC-141b), chlorodifluoroethane (HCFC-142b), trifluoromethane (HFC-23), 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), cyclic branched, or linear, completely fluorinated alkan
Camba Jose
Jibrail Joseph
May Michael
Peeler Calvin
Rickner Stephen
BASF Corporation
Bissett Melanie
Borrego Fernando A.
Seidleck James J.
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