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
2001-09-18
2003-02-04
Niland, Patrick D. (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...
C524S590000, C524S591000, C524S839000, C524S840000, C528S044000, C528S060000, C528S061000, C528S065000, C528S085000
Reexamination Certificate
active
06515070
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a polymer component having controlled branching and which is suitable to be used as an adhesive. In the case of polyurethane or polyurethaneurea polymers, controlled branching can be achieved through the incorporation of polyfunctional components into the polymer forming or prepolymer forming reaction.
BACKGROUND OF THE INVENTION
There has been significant interest in the development of solvent-free aqueous polyurethane dispersions for a number of industrial applications, including adhesives, coatings, and inks. The high viscosity of the intermediate prepolymers usually requires that a viscosity-reducing agent, for example, such as a solvent, be added prior to the dispersion step. See, e.g., Dieterich, D.,
Progress in Organic Coatings,
9, 281 (1981).
The use of certain isocyanate components, such as TMXDI®, (m-tetramethylxylylene diisocyanate, a trademark of Cytec Industries), that do not undergo self-condensations typical of other conventional isocyanate components can be incorporated into preparations, allowing lower viscosity prepolymers to be made without necessarily adding any viscosity-reducing agents. Several publications listed below have utilized TMXDI in adhesive formulations, some with viscosity-reducing agents, such as organic solvents.
U.S. Pat. No. 5,432,228 to Hilken et al., discloses adhesive compositions and processes for bonding substrates together using the adhesive compositions. The compositions are made by a process combining a prepolymer reaction product of an organic isocyanate, a polyhydroxyl compound, and a low molecular weight polyhydric alcohol or aminoalcohol, with a mixture of monoamino and diamino compounds to chain extend and chain terminate the prepolymer. This patent also addresses the change of heat resistance over time, with respect to heat activation.
U.S. Pat. No. 5,608,000 to Duan et al., discloses aqueous dispersion adhesives that have high heat resistance and low activation temperature. To attain these properties, chain extension of a prepolymer made from a diisocyanate and a mixture including a sulfonate-pendant polyester polyol, a hydroxy carboxylic acid, and a low molecular weight diol is required. Also, the only examples showing excellent heat resistance, defined as no failure at all, are samples prepared using a process in which acetone, a common organic solvent, is added.
U.S. Pat. No. 5,703,158 to Duan et al., as well as related PCT Publication No. WO 95/08583 to H. B. Fuller Licensing & Financing, Inc., disclose aqueous dispersions, and processes for making such dispersions, that contain polymers having either sulfonate or a mixture of sulfonate and carboxylate groups. These patents also discuss the reduction in crystallization of adhesive formulations containing TMXDI.
Other publications, such as
TMXDI
® (
Meta
)
Aliphatic Isocyanate, The Choice for Aqueous Polyurethane Dispersions, December
1999, have disclosed that TMXDI may be used in prepolymers for dispersions in coating applications. However, those prepolymers can not typically be used as adhesives because the temperature needed to activate them, greater than about 100° C., is too high for practical use.
Many other publications describe polyurethane polymers or prepolymers used in dispersions, or the dispersions themselves, as well as the process of making such polymers, prepolymers, or dispersions. Examples of such publications include U.S. Pat. Nos. 4,147,679; 4,528,323; 4,558,090; 4,914,148; 5,155,163; 5,494,960; and 5,907,012.
It is desirable to find a polymer composition useful for adhesive applications, which does not require the addition of organic solvent and which has excellent heat activation and resistance properties. In addition, it is beneficial to have the ability to control the heat resistance of such dispersions further by manipulating the molecular architecture of the polymer in the dispersion.
SUMMARY OF THE INVENTION
The present invention relates to polymer having controlled branching formed from the reaction product of a prepolymer and a chain extender, which prepolymer is itself formed from the reaction product of a mixture of a non-self-associating isocyanate component, a diol component having a molecular weight from about 1500 to 6000 grams/mole, and present in an amount greater than about 50% by weight based on the total weight of the prepolymer and an ion-forming compound. The chain extender comprises an amine-containing compound and is present in an amount sufficient to react with at least about 99% of the isocyanate groups present after the prepolymer has been formed. The controlled branching of the polymer comprises at least one of:
a hydroxy-functional component having hydroxyl functionality greater than 2.0 and having a molecular weight from about 700 to 2000; or
a low molecular weight component having more than two hydroxyl groups.
Advantageously, the polymer can also have a substantial lack of uncontrolled branching.
In one embodiment, the non-self-associating isocyanate component includes TMXDI. In another embodiment, the ion-forming compound contains at least one carboxylic acid group. In a preferred embodiment, the carboxylate content is from about 1% to 10%, preferably from about 3.5% to 8%, more preferably from about 4% to 6%, by weight of the ion-forming compound, based on the total weight of the polymer after being chain extended.
The present invention is also directed to a process for preparing an adhesive, which comprises:
reacting a mixture of a non-self-associating isocyanate component, a diol component having a molecular weight from about 1500 to 6000 grams/mole, and present in an amount greater than about 50% by weight based on the total weight of the prepolymer and an ion-forming compound, to form a polyurethane prepolymer;
neutralizing an ion-forming moiety on the prepolymer; and
chain extending the prepolymer with an amine-containing compound so that the polymer component, which amine-containing component is present in an amount sufficient to react with at least about 99% of the isocyanate groups present after the prepolymer has been formed,
wherein the controlled branching of the polymer comprises at least one of:
a hydroxy-functional component having hydroxyl functionality greater than 2.0 and having a molecular weight from about 700 to 2000; or
a low molecular weight component having more than two hydroxyl groups.
The present invention also relates to an adhesive for bonding together two substrates comprising any of the polymers of the present invention or polymers that can be made by a process of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Definitions
The term “solvent,” as used herein, should be understood to mean any chemical compound, preferably a liquid, that has the capability of dissolving components that are added to it. “Solvent” herein does not refer to or include water.
The term “molecular weight”, as used herein means number average molecular weight.
The term “low molecular weight,” as used herein, refers to molecular weights not more than about 400 grams/mole.
The term “polyol,” as used herein, refers to a compound comprising three or more hydroxyl groups available for reaction.
The term “polyfunctional,” as used herein in reference to a compound, refers to the presence of more than two functional groups capable of participating in a reaction with other components. Based on the present disclosure and the context of the usage of this term, it should be obvious to those of ordinary skill in the art with which other components the functional groups are capable of reacting.
The term “solvent-free,” as used herein in reference to a composition of matter, indicates that no external solvent component has been added to the composition at any time. It should be understood by one of ordinary skill in the art that residual solvents may be present inherently in commercially available or synthesized products, which inherent presence is not precluded by use of the term “solvent-free.”
The phrase “controlled branching,” as used herein in r
Iey David A.
Kobylanska Irina
Konkus David M.
Cytec Technology Corp.
Didamo Valerie T.
Jubinsky James A.
Niland Patrick D.
Schultz Claire M.
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