Stock material or miscellaneous articles – Composite – Of quartz or glass
Reexamination Certificate
1997-04-11
2002-10-22
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of quartz or glass
C428S441000, C428S480000, C428S482000, C428S500000, C525S048000, C525S049000, C525S165000, C525S531000
Reexamination Certificate
active
06468662
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to laminating resins. More particularly, the present invention relates to laminating resins having a low volatile monomer content.
BACKGROUND OF THE INVENTION
Laminating resins have long been used in conjunction with solid materials, typically those which are thermoset or thermoplastic materials which are reinforced by fibers. Typically, the resins are coated, sprayed, or brushed onto components which are used as panels forming the exterior bodies of vehicles, marine vessels, and other molded articles. Subsequently, the component is subjected to specified conditions such as temperature so as to cure the resin. The laminated resin is useful in that it imparts desirable physical properties to the panel. In particular, the cured resin typically displays adequate strength, toughness, elongation, heat distortion temperature, and chemical resistance properties. Moreover, the resin is desirable in that it provides a finished appearance to the exterior body.
A traditional laminating resin is typically formed from several components including unsaturated polyesters and bisphenol compounds such as difunctional bisphenol-A acrylic esters. The resin also typically includes a volatile monomer diluent such as styrene or vinyl toluene to facilitate employing the resin as a liquid.
The use of volatile monomers, however, have become disfavored due to alleged increased environmental risks. For example, U.S. Pat. No. 5,393,830 to Smeal et al. proposes a laminating resin which employs a reduced amount of styrene so as to meet a specified volatile emission test standard. The resin comprises a polyester resin, ethylene glycol dimethacrylate, vinyl toluene, cyclohexyl methacrylate, and bisphenol-A dimethacrylate.
The use of bisphenol-A dimethacrylate in a laminating resin, however, suffers from various drawbacks. For example, utilizing the bisphenol compound in forming a laminating resin is unduly complex from a processing standpoint in that multiple lengthy steps are needed before achieving the final resin end product. Moreover, the bisphenol-A dimethacrylate material is often one of the more expensive components used in formulating the laminating resin.
In view of the above, it is an object of the present invention to provide a laminating resin composition which utilizes a reduced level of volatile monomer diluent such as styrene.
It is a further object of the present invention to provide a laminating resin exhibiting good end properties which employs relatively less expensive starting material and is produced from a simpler process relative to conventional processes.
SUMMARY OF THE INVENTION
To these ends and others, the present invention provides a laminating resin which has low volatile monomer content and exhibits advantageous physical properties, especially with respect to toughness. Specifically, the laminating resin comprises an unsaturated polyester resin, a vinyl ester resin, a polyfunctional acrylate, and less than about 15 percent by weight of vinyl monomer.
The unsaturated polyester resin preferably has a weight average molecular weight ranging from about 300 to 2000. In such an embodiment, the laminating resin further comprises a component selected from the group consisting of acrylic acid, methacrylic acid, cinnamyl alcohol, crotonic acid, cinnamic acid, sorbic acid, maleic acid, fumaric acid, itaconic acid, benzoic acid, benzyl alcohol, cyclohexanol, 2-ethyl hexanol, trimethylol propane diallyl ether, and mixtures thereof.
The vinyl ester resin preferably has a weight average molecular weight ranging from about 450 to 1500 and is the reaction product of an unsaturated polycarboxylic acid or anhydride with an epoxy resin.
The laminating resin may optionally contain other components. In one embodiment, the laminating resin further comprises a dicyclopentadiene resin.
In a preferred embodiment, the laminating resin comprises from about 25 to 50 percent by weight of an unsaturated polyester resin, from about 1 to 75 percent by weight of a vinyl ester resin, from about 1 to 15 percent by weight of a polyfunctional acrylate, less than about 15 percent by weight of a vinyl monomer, and from about 5 to 25 percent by weight of a dicyclopentadiene resin.
The invention also relates to an article of manufacture. The article of manufacture comprises a substrate comprising reinforcing fibrous material and a laminating resin coated onto the substrate. The laminating resin comprises an unsaturated polyester resin, a vinyl ester resin, a polyfunctional acrylate, and less than about 15 percent by weight of a vinyl monomer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As summarized above, the present invention relates to a laminating resin which includes an unsaturated polyester resin, a vinyl ester resin, a polyfunctional acrylate, and less than about 15 percent by weight of a vinyl monomer. For the purposes of the invention, the term “laminating resin” is to be broadly interpreted to include any resin which may be applied to or coated on a suitable substrate. Laminating resins, for example, may include gel coat resins.
The unsaturated polyester resin is typically formed from the reaction between a polybasic acid or anhydride and an alcohol. Known and suitable processes for preparing such polyesters may be employed for the purpose of the present invention.
Suitable polybasic acids or anhydrides thereof include dicarboxylic acids such as, but not limited to, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexane dicarboxylic acid, succinic acid, adipic acid, sebacic acid, azealic acid, malonic acid, alkenyl succinic acids such as n-dodecenylsuccinic acid, docecylcucinic acid and octadecenylsuccinic acid, and mixtures thereof. Lower alkyl esters of any of the above may also be employed.
The polybasic acid or anhydride may be employed in any suitable amount, preferably of from about 20 to 55 percent based on the weight of the unsaturated polyester resin.
Any alcohols which are appropriate in polyester-forming reactions are utilized. Such compounds include, but are not limited to, ethylene glycol, diethylene propylene glycol, diethylene glycol, neopentyl glycol, dipropylene glycol, poly-tetramethylene glycol, bispolyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(3.3)-2,2-bis(4-bis(4-hydroxyphenyl)propane, polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(2.0)-polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, and polyoxypropylene(6)-2,2-bis(4-hydroxyphenyl)propane. Diols may be employed and include, for example, 1,5-pentanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. Polyhydric alcohols are also suitable and include, for example, sorbitol, 1,2,3,6-hexatetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methyl propanetriol, 2-methyl 1,2,4-butanetriol, trimethylol ethane, trimethylol propane, and 1,3,5-trihydroxyethyl benzene. Mixtures of any of the above may be used.
The alcohols may be employed in any suitable amount, preferably of from about 10 to 60 percent based on the weight of the unsaturated polyester resin.
Although not wishing to be bound by any theory, the molecular weight of the unsaturated polyester resin is believed to be controlled by end capping the polyester resin with a monovalent radical under known and suitable processing conditions. In this instance, the unsaturated polyester resin preferably has a weight average molecular weight ranging from about 300 to 2000, and more preferably from about 500 to 1000. The monovalent radical used to end cap the polyester resin may be selected from the group consisting of acrylic acid, methacrylic acid, cinnamyl alcohol, crotonic acid, cinnamic acid, sorbic acid, maleic acid, fumaric acid, itaconic acid, benzoic acid, benzyl alcohol, cyclohexanol, 2 ethylhexanol, and trimethylol propane diallyl ether. Mixtures of the above may be used. T
Aylward D.
Dawson Robert
Myers Bigel Sibley & Sajovec, PA.
Reichhold Inc.
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