Coating processes – With post-treatment of coating or coating material – Heating or drying
Reexamination Certificate
1999-08-24
2001-01-09
Wilson, Donald R. (Department: 1713)
Coating processes
With post-treatment of coating or coating material
Heating or drying
C428S375000, C521S048500, C525S172000, C525S174000, C525S439000, C525S444000
Reexamination Certificate
active
06171654
ABSTRACT:
This invention relates to water-soluble or water-dispersible and curable polyester resins. The resins can be made from waste plastic materials which would otherwise be discarded in landfills or other solid waste deposit facilities.
The curable polyester resins can be used as curable binders for a number of applications, especially for binding glass fibers in the production of fiberglass insulation products.
BACKGROUND OF THE INVENTION
Glass fibers have long been noted for their insulating value. However, depending upon the end use of the insulation, there are certain disadvantages to be found in glass fiber insulation now in general use. It is well known that in fibrous insulation the respective fibers are bonded to one another by a suitable binder system which normally consists of a phenolic liquid resole resin or a conventional phenolic-formaldehyde resin in combination with various additives. The additives are used to improve either the process characteristics of the binder system or to improve the finished fiberglass product characteristics.
Processes for making mineral fiber thermal insulation are typically carried out according to one of a number of methods wherein the molten mineral material flowing from a melting furnace is divided into streams and attenuated into fibers. The attenuation is done by centrifuging and/or fluid jets to form discontinuous fibers of relatively small dimensions which are collected by randomly depositing on a moving foraminous conveyor belt. The fibers are collected in a felted haphazard manner to form a mat. The volume of fiber in the mat will be determined by the speed of fiber formation and the speed of the belt. In order to produce most thermal insulating products, the fibers must be bonded together in an integral structure. To achieve this binding, a curable binder material is added to the mineral wool. The curable binder composition is generally formulated as a liquid to be sprayed onto the fibers as they are dropping onto the collecting conveyor belt. The layer of fiber with binder is then compressed and shaped into the form and dimensions of the desired thermal insulating product and passed through a curing oven where the binder is cured fixing the size and shape of the finished insulating product. Various materials have been used as binder ingredients including both organic and inorganic materials generally blended for different properties. The organic binder material most commonly employed are heat curable thermosetting resin systems of the phenol-formaldehyde type.
Such binders are generally provided as water soluble or water dispersable compositions which can be easily blended with other ingredients and diluted to low concentrations which are readily sprayed onto the fiber as it falls onto the collecting conveyor. The binder composition is generally applied in an amount such that the cured binder constitutes about 5% to about 10% by wt. of the finished product though it can be as little as 1% or less or as high as 20% or more, depending upon the type of fiber product. Optimally, the amount of binder for most thermal insulating products will be the amount necessary to lock each fiber into the mass by bonding the fibers where they cross or overlap. For this reason, it is desired to have binder compositions with good flow characteristics so that the binder solution can be applied to the fiber at a low volume that will flow to the fiber intersections.
Generally, the binder system requirements are for a low cost water soluble or water dispersable composition which can be easily applied and readily cured during normal production cycles. The product should be relatively stable for periods of time long enough to permit mixing and application at temperatures ordinarily encountered in fiberizing plants and the composition should be dilutable in order to permit variations in concentrations for different end products. The cured binder product must provide a strong bond with sufficient elasticity and thickness recovery to permit reasonable shipping and in-service deformation of the thermal insulating product. It must be moisture resistant so that it will not swell under humid conditions. It must be odor free and non-corrosive to metals with which it comes in contact. The binder should be capable of withstanding temperatures as high as the temperature that the mineral fiber can withstand, particularly for pipe insulation where the pipeline is used for hot fluids. The mineral fibers can be any of the materials which are capable of being fiberized. Typical binder compositions for glass are prepared as aqueous solutions or dispersions of partially condensed phenolic formaldehyde resins to which are added a variety of modifiers or agents to improve the spraying, flowing or similar application characteristics as well as the bonding strength, temperature resistance and other in-service features of the cured resin.
DESCRIPTION OF THE PRIOR ART
Altenberg, in U.S. Pat. No. 4,604,410, has proposed making etherified aromatic polyols by digesting scrap polyalkylene terephthalate with a low molecular weight polyhydroxy compound, containing 3-8 hydroxyl groups. A resulting intermediate is alkoxylated with 1-4 moles of ethylene oxide and/or propylene oxide. The final product is useful in making polyurethane and polyisocyanurate foams.
Sperenza et al. (U.S. Pat. No. 4,485,196) have recited reacting recycled polyethylene terephthalate scrap with an alkylene oxide, such as propylene oxide. The product can be used in making rigid foams.
Other methods of reacting scrap polyalkylene terephthalate with glycols or polyols are proposed by Svoboda et al. (U.S. Pat. No. 4,048,104) and Altenberg et al. (U.S. Pat. No. 4,701,477). In our previous invention (U.S. Pat. No. 4,977,191 (Salsman)) we disclosed a water-soluble or water-dispersible polyester resin suitable for textile sizing applications. The polyester resin comprises a reaction product of 20-50% by weight of waste terephthalate polymer, 10-40% by weight of at least one glycol and 5-25% by weight of at least one oxyalkylated polyol. Preferred compositions also comprise 20-50% by weight of isophthalic acid. A further water-soluble or water-dispersible resin comprises a reaction product of 20-50% by weight of waste terephthalate polymer, 10-50% by weight of at least one glycol and 20-50% by weight of isophthalic acid.
U.S. Pat. No. 5,252,615 (Rao et al.) discloses coating compositions derived from alcoholysis of polyethylene terephthalate (PET). Most preferably, the PET is recycled or reclaimed from plastic articles.
Dale et al., in U.S. Pat. No. 4,104,222, have proposed making a dispersion of linear polyester resins by mixing linear polyester resin with a higher alcohol/ethylene oxide addition-type surface-active agent, melting the mixture and dispersing the resulting melt in an aqueous alkali solution. The products are used as coating and impregnating agents.
U.S. Pat. No. 4,542,068 (Whichard) is directed to a method of making glass fiber mat of improved tensile strength. The method comprises forming a wet mat of a plurality of enmeshed sized glass fibers in a wet-laid process and coating the fiber of the wet mat with a binder and drying the mat. The binder consists essentially of a urea-formaldehyde resin and alkoxylated alkyl amine surfactant.
The prior art is silent regarding the binders of the present invention as well as fiberglass insulation products containing such binders.
OBJECTS OF THE INVENTION
It is an object of the invention to produce a curable polyester resin.
It is another object of the invention to utilize waste material in the production of polyester resins.
It is still another object of the invention to use the cured polyester resin as a binder in various applications.
It is a further object of the invention to make rolls or sheets of fiberglass insulating material using the cured polyester.
Another object of the present invention is to provide fibrous insulation formed by glass fibers bonded together with a low cost, stable and zero emission binder system which is convenient to use, and satisfi
Salsman Robert Keith
Wang Timothy Shouting
Angres Isaac
Flint Cort
Seydel Research, Inc.
Wilson Donald R.
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