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
2000-03-02
2001-12-11
Moore, Margaret G. (Department: 1712)
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...
C524S718000, C525S431000
Reexamination Certificate
active
06329462
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to processes for making nylon 6 polymer compositions that are modified with a silicone polymer emulsion comprising a silicone polymer to provide a nylon 6/silicone polymer blend. The silicone polymer emulsion may comprise water, diol, caprolactam, or a mixture thereof. The silicone polymer emulsion may also optionally comprise cosolvents. The invention further relates to nylon 6/silicone polymer blends.
BACKGROUND OF THE INVENTION
Silicone rubber has been utilized as a low Tg polymer for modifying polymers, such as polyamides. U.S. Pat. No. 5,610,223 discusses the mixing of silicone rubber powder into polyamide. This composition is a physical blend of silicone rubber and polyamide. Such melt mixing techniques are expensive and time consuming; thus, it would be beneficial to be able to combine silicone polymers with materials such as polyamide without the need for such mixing.
There exists a need for a process for producing a polymer blend by more economical methods. Such a need has been solved by the present invention, which can achieve such a blend in a polymerization reactor, wherein the physical properties of the condensation polymer are maintained or improved.
SUMMARY OF THE INVENTION
In one aspect, the invention provides a method of making a nylon 6/silicone polymer blend comprising the steps of:
a. preparing a silicone polymer emulsion comprising a silicone polymer dispersed in a liquid continuous phase;
b. introducing the silicone polymer emulsion into a nylon 6 ring opening reaction either prior to or during the nylon 6 ring opening reaction medium, wherein the reaction medium comprises caprolactam; and
c. opening the ring and reacting the caprolactam, thereby providing a nylon 6/silicone polymer blend.
In another aspect, the invention provides a nylon 6/silicone polymer blend comprising nylon 6 and a silicone polymer emulsion, wherein the silicone polymer of the nylon 6/silicone polymer blend is derived from a silicone polymer emulsion, wherein the blend is formed by introducing the silicone polymer emulsion into a nylon 6 ring opening reaction either prior to or during the nylon 6 ring opening reaction medium and wherein the reaction medium comprises caprolactum.
Still further, the invention provides introducing a silicone polymer emulsion into a nylon 6 polymer, followed by extrusion, thereby providing a nylon 6/silicone polymer blend.
Additional advantages of the invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
DETAILED DESCRIPTION OF THE INVENTION
The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the Examples included therein.
Before the present compositions of matter and methods are disclosed and described, it is to be understood that this invention is not limited to specific synthetic methods or to particular formulations, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings:
The singular forms “a” “an” and “the” include plural referents unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstances may or may not occur, and that the description included instances where said event or circumstance occurs and instances where it does not.
“Silicone polymer emulsion” is herein defined as a dispersion of polymeric particles in a continuous phase, the polymeric particles preferably having a size range of from about 0.10 to about 1000 microns. Further preferably, the polymeric polymers have a particle size of from about 0.1 to about 10 microns. The silicone polymers of the present invention preferably have a molecular weight of about 5,000 to about 1,000,000 Daltons. The polymeric particles are preferably produced through emulsion polymerization processes. Alternatively, such emulsions may be prepared through direct emulsification e.g., mechanical emulsification processes.
As used herein, nylon 6 is a polymer of caprolactam.
The abbreviation “nm” means nanometers. “Tg” means glass transition temperature.
Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains.
Ranges are often expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value is another embodiment.
In a major aspect, the invention is concerned with the introduction of a silicone polymer into a nylon 6 ring opening reaction wherein the silicone polymer is preferably introduced via a silicone polymer emulsion. The silicone polymer emulsion may comprise water, caprolactam., or a mixture thereof. Polymer blends made by these methods are also provided. The silicone polymer emulsion may also be added to a fully formed nylon 6 polymer, followed by extrusion to provide a nylon 6/silicone polymer blend.
I. Silicone Polymer Emulsion
In one embodiment, the aqueous silicone polymer emulsions of the present invention comprise a plurality of particles of a silicone polymer dispersed in a continuous phase. The silicone polymers of the present invention may preferably have functional groups. Such functional groups may comprise amino, epoxy, vinyl, mercapto, carbonate, isocyanate or silicone hydride. In a particularly preferred embodiment, the silicone polymer is a silanol terminated polydiorganosiloxane (“PDOS”). Other preferred silicone polymers include alkylmethylsiloxanes or aminopropylsiloxanes.
The silicone polymer emulsion preferably contains at least one surfactant that stabilizes the dispersed silicone polymer particles in the continuous phase of the emulsion. The silicone polymer in the emulsion should preferably have an average particle size from about 0.1 to about 1000 microns, more preferably from about 0.1 to about 10 microns. Such emulsions may be prepared, for example, by methods wherein a cyclic or linear oligomeric silicone polymer, such as PDOS, are dispersed in an aqueous continuous phase with the aid of the above mentioned surfactant and are thereafter emulsion polymerized by the introduction of an acid or base catalyst. Such emulsions can be illustrated by the disclosures of, among others, U.S. Pat. Nos. 4,954,565, 4,618,642, 3,294,725, and 2,891,920, the disclosures of which are each hereby incorporated herein in their entireties by this reference.
In a preferred embodiment, the silicone polymer emulsions are prepared by a direct emulsification process. In this process, a mixture of the continuous phase liquid i.e., water and/or, caprolactam and one or more surfactants are processed with a silicone polymer dispersed phase under high shear conditions using either conventional mixing equipment or high shear devices such as a Microfluidizer™. Methods for preparing these polymer emulsions are given in U.S. Pat. Nos. 4,177,177 and 4,788,001, the disclosures of which are each herein incorporated in their entireties by this reference
Hale Wesley R.
Jones Allan Scott
Murray David Logan
Eastman Chemical Company
Graves, Jr. Esq. Bernard J.
Moore Margaret G.
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