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
1999-04-14
2002-02-26
Cain, Edward J. (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...
C524S122000, C524S127000, C525S391000
Reexamination Certificate
active
06350804
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
FEDERALLY SPONSORED RESEARCH
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to compositions comprising an organically modified layered silicate clay generally referred to as organoclay and polyphenylene ether resin and blends containing polyphenylene ether resin.
In a preferred embodiment, the compositions exhibit physical properties that are enhanced over compositions containing clay of the prior art. The invention also relates to methods to enhance the ductility of thermoplastic compositions as compared to compositions containing clay of the prior art. The invention also relates to articles made from the compositions.
2. Brief Description of the Related Art
Many commercial articles, such as connectors and automotive under hood components, require levels of stiffness and heat resistance that are greater than most thermoplastic resins. Inorganic fillers have been used to increase the stiffness and heat resistance of thermoplastic resins, however, concomitant with an unacceptable loss in ductility for many applications.
Organoclay materials have been used in crystalline resins, e.g., polyesters and polyamide resins, to enhance the flame and/or temperature resistance characteristics. The utility of organoclay material to enhance the ductility of thermoplastic resins is believed to be novel and non-obvious.
SUMMARY OF THE INVENTION
The present invention relates to compositions comprising:
(i) polyphenylene ether resin and blends containing polyphenylene ether resin, and
(ii) an organoclay.
The invention also relates to methods to enhance the ductility of thermoplastic compositions as compared to compositions containing clay of the prior art. The invention also relates to articles made from the compositions and methods.
The description which follows provides further details regarding this invention.
DESCRIPTION OF THE DRAWINGS
Not applicable.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, organoclay is a layered silicate clay, derived from layered minerals, in which organic structures have been chemically incorporated. Illustrative examples of organic structures are trimethyldodecylammonium ion and N,N′-didodecylimidazolium ion. Since the surfaces of clay layers, which have a lattice-like arrangement, are electrically charged, they are capable of binding organic ions. There is no limitation with respect to the layered minerals employed in this invention other than that they are capable of undergoing an ion exchange with the organic ions. The preferred organoclays are layered minerals that have undergone cation exchange with organo cations and/or onium compounds. Illustrative of such layered minerals are the kaolinite group and the montmorillonite group. It is also within the scope of this invention to employ minerals of the illite group which can include hydromicas, phengite, brammallite, glaucomite, celadonite and the like. Often, however, the preferred layered minerals include those often referred to as 2:1 layered silicate minerals like muscovite, vermiculite, saponite, hectorite and montmorillonite, wherein montmorillonite is often preferred. The layered minerals described above may be synthetically produced. However, most often they are naturally occurring and commercially available. A detailed description of the layered minerals can be found in U.S. Pat. No. 5,530,052 which is incorporated herein by reference.
The amount of organoclay present in the compositions of the invention can vary depending on the final properties desired. Generally, the level is adjusted to allow for the desired level of increased stiffness, heat resistance, and/or dimensional stability balanced against the level of achievable ductility. Typical levels include from about 1% to about 25% by weight, preferably between about 1% to about 15% by weight, based upon the entire weight of the composition.
Descriptions of useful resins for the practice of the present invention are provided as follows.
Polyphenylene Ether Resin and Blends Containing Polyphenylene Ether Resin.
Polyphenylene ether resin, hereinafter “PPE”, per se, are known polymers comprising a plurality of structural units of the formula (I):
wherein for each structural unit, each Q
1
is independently halogen, primary or secondary lower alkyl (e.g., alkyl containing up to 7 carbon atoms), phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and each Q
2
is independently hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy as defined for Q
1
. Preferably, each Q
1
is alkyl or phenyl, especially C
1-4
alkyl, and each Q
2
is hydrogen.
Both homopolymer and copolymer PPE are included. The preferred homopolymers are those containing 2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers include random copolymers containing, for example, such units in combination with 2,3,6-trimethyl-1,4-phenylene ether units. Also included are PPE containing moieties prepared by grafting vinyl monomers or polymers such as polystyrenes, as well as coupled PPE in which coupling agents such as low molecular weight polycarbonates, quinones, heterocycles and formals undergo reaction in known manner with the hydroxy groups of two PPE chains to produce a higher molecular weight polymer.
It will be apparent to those skilled in the art from the foregoing that the PPE contemplated for use in the present invention include all those presently known, irrespective of variations in structural units or ancillary chemical features.
The PPE generally have an intrinsic viscosity often between about 0.05-0.60 dl./g., preferably in the range of about 0.10-0.48 dl./g., all as measured in chloroform at 25° C. It is also possible to utilize a high intrinsic viscosity PPE and a low intrinsic viscosity PPE in combination. By high viscosity is meant a PPE having an I.V. of at least about 0.30 dl/g, and conversely, by low is meant a PPE with an I.V. of less than about 0.30 dl/g, preferably less than about 0.20 dl/g. Determining an exact ratio, when two intrinsic viscosities are used, will depend somewhat on the exact intrinsic viscosities of the PPE used and the ultimate physical properties that are desired.
The PPE resin compositions of the present invention preferably contain at least one nonelastomeric polymer of an alkenylaromatic compound. Suitable polymers of this type may be prepared by methods known in the art including bulk, suspension and emulsion polymerization. They generally contain at least about 25% by weight of structural units derived from an alkenylaromatic monomer of the formula (II)
wherein G is hydrogen, lower alkyl or halogen; Z is vinyl, halogen or lower alkyl; and p is from 0 to 5. These resins include homopolymers of styrene, chlorostyrene and vinyltoluene, random copolymers of styrene with one or more monomers illustrated by acrylonitrile, butadiene, &agr;-methylstyrene, ethylvinylbenzene, divinylbenzene and maleic anhydride, and rubber-modified polystyrenes comprising blends and grafts, wherein the rubber is a polybutadiene or a rubbery copolymer of about 98-68% styrene and about 2-32% diene monomer. These rubber modified polystyrenes include high impact polystyrene (commonly referred to as HIPS). Non-elastomeric block copolymer compositions of styrene and butadiene can also be used that have linear block, radial block or tapered block copolymer architectures. They are commercially available from such companies as Fina Oil as under the trademark FINACLEAR and Phillips under the trademark K-RESINS.
The amount of the polymer of a nonelastomeric alkenylaromatic compound, when one is used, is an amount effective to improve the flow and processability of the composition. Improved flow can be indicated by reduced viscosity or reduced injection pressures needed to fill a part during an injection molding process. Generally, the nonelastomeric alkenylaromatic compound is utilized in the range of about 20% to a
Adedeji Adeyinka
Campbell John R.
Khouri Farid Fouad
Rodgers Patrick A.
Cain Edward J.
General Electric Co.
Wyrozebski-Lee Katarzyna
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