Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-08-30
2003-09-16
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S133000, C525S063000, C525S390000, C525S391000, C525S397000
Reexamination Certificate
active
06620885
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to polyphenylene ether resins and more specifically, relates to the manufacture of copolymers of functionalized polyphenylene ether resins having properties controlled by crosslinking and blends thereof. In one embodiment, the invention relates to reaction products between a polyphenylene ether resin containing functional groups and a polymer such as styrene acrylonitrile and blends thereof.
2. Brief Description of the Related Art
Polyphenylene ether (PPE) resins (also known within the art as “Polyphenylene Oxide”) are an extremely useful class of high performance engineering thermoplastics by reason of their hydrolytic stability, high dimensional stability, toughness, heat resistance and dielectric properties. PPE resins are commercially attractive materials because of their unique combination of physical, chemical, and electrical properties. This unique combination of properties renders PPE resin based formulations suitable for a broad range of applications that are well known in the art. One example is injection molded products which are used for high heat applications. The more common PPE resins known in the art are typically comprised of PPE polymers of a fairly high molecular weight. These PPE polymers generally have in excess of 50 repeat monomer units, most often in excess of 80 or more repeat monomer units.
There is much interest in the art in providing blends of PPE resins with other resins such as styrenic resins. One material of interest has been Styrene-Acrylonitrile copolymer (“SAN”) resins. Styrene-Acrylonitrile copolymer resins are transparent resins used in a variety of products including housewares, packaging, appliances, industrial batteries, and automotive and medical applications. In these markets, SAN resins are used because of their low unit cost, clarity, heat resistance, good processability and resistance to chemicals.
One technical obstacle to the development of some PPE resin/styrenic resin blends has been the lack of compatibility between PPE resin and certain styrenic resins. This lack of compatibility is often due to poor miscibility and manifests itself often through very poor physical properties as well as de-lamination in molded parts.
Efforts to create an integrated material of PPE resin and SAN resin have been met with difficulties. Methods for improving the miscibility of PPE polymers with certain styrenic polymer resins, such as SAN resins, are desired.
BRIEF SUMMARY OF THE INVENTION
In one aspect of the invention, a copolymer miscible with styrenic resins is disclosed which comprises PPE segments and segments of one or more styrene units, acrylonitrile units and combinations of styrene and acrylonitrile units, optionally containing other chemical species, e.g., rubbery species. The PPE segments are derived from a PPE resin comprising PPE polymer chains having at least one end cap containing a pair of unsaturated aliphatic carbon atoms, i.e. a carbon—carbon double bond.
The term “miscible” as used herein, refers to the ability of two polymers to form a single phase when melt blended together. This single phase can be identified by a single glass transition temperature.
In another aspect, this invention provides a composition comprising: a copolymer of this invention, and a styrenic resin, such as polystyrene (PS), styrene copolymers (such as SAN) and combinations thereof.
In a further aspect, a method for making a copolymer composition is disclosed. The method comprises introducing a PPE resin into a reaction medium comprising at least styrenic monomers and acrylonitrile monomers, wherein the amount of PPE resin is 5 to 20 wt % of the total combined weight of the PPE resin, the styrenic monomers and the acrylonitrile monomers and any additional optional co-polymerizable monomers. The PPE resin comprises at least one PPE polymer chain having at least one end cap that has a pair of unsaturated aliphatic carbon atoms, i.e. at least one carbon—carbon double bond. The PPE resin, styrenic monomers and acrylonitrile monomers loaded in the reaction medium are subsequently polymerized into a PPE copolymer. The reaction medium can be a bulk reaction medium or a reaction medium that contains another liquid which suspends or emulsifies the reactive components.
The PPE resin employed to provide PPE segments comprises PPE polymer chains. These PPE polymer chains are known polymers comprising a plurality of phenylene ether units of the formula (I):
Each structural unit may be the same or different, and in each structural unit, each Q
1
is independently a halogen, primary or secondary lower alkyl (i.e., alkyl containing up to 7 carbon atoms), phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy, at least two carbon atoms separate the halogen and oxygen atoms; and each Q
2
is independently a hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy as defined for Q
1
. Most often, each Q
1
is alkyl, especially C
1-4
alkyl, and each Q
2
is hydrogen or alkyl, especially C
1-4
alkyl.
Specific polyphenylene ether polymers useful in the present invention include but are not limited to
poly(2,6-dimethyl-1,4-phenylene ether);
poly (2,6-dimethyl-co-2,3,6-trimethyl-1,4-phenylene ether);
poly(2,3,6-trimethyl-1,4-phenylene ether);
poly(2,6-diethyl-1,4-phenylene ether);
poly(2-methyl-6-propyl-1,4-phenylene ether);
poly(2,6-dipropyl-1,4-phenylene ether);
poly(2-ethyl-6-propyl-1,4-phenylene ether);
poly(2,6-dilauryl-1,4-phenylene ether);
poly(2,6-diphenyl-1,4-phenylene ether);
poly(2,6-dimethoxy-1,4 phenylene ether);
poly(2,6-diethoxy-1,4-phenylene ether);
poly(2-methoxy-6-ethoxy-1,4-phenylene ether);
poly(2-ethyl-6-stearyloxy-1,4-phenylene ether);
poly(2,6-dichloro-1,4-phenylene ether);
poly(2-methyl-6-phenyl-1,4-phenylene ether);
poly(2-ethoxy-1,4-phenylene ether);
poly(2-chloro-1,4-phenylene ether);
poly(2,6-dibromo-1,4-phenylene ether);
poly(3-bromo-2,6-dimethyl-1,4-phenylene ether); or mixtures thereof.
Suitable PPE resins include homopolymers and copolymers of the structural units of formula I. The preferred homopolymers are those containing 2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers include random and blocked copolymers containing such units in combination with, for example, 2,3,6-trimethyl-1,4-phenylene ether units to produce poly (2,6-dimethyl-co-2,3,6-trimethyl-1,4-phenylene ether) resins. Also included are PPE resins containing moieties prepared by grafting vinyl monomers or polymers such as polystyrenes and elastomers, as well as coupled PPE resins in which coupling agents such as low molecular weight polycarbonates, quinones, heterocycles and formals undergo reaction in a known manner with the hydroxy groups of two poly(phenylene ether) polymer chains to produce a higher molecular weight polymer, provided a substantial proportion of free hydroxyl groups remains.
The term “polyphenylene ether resin,” (and “PPE resins”) as used in the specification and claims herein, includes unsubstituted polyphenylene ether polymers, substituted polyphenylene ether polymers wherein the aromatic ring is substituted, polyphenylene ether copolymers and blends thereof.
The PPE resins contemplated for use in the present invention include all those presently known, irrespective of variations in structural units or ancillary chemical features. The molecular weight of the polymers that form the PPE resin and the intrinsic viscosity of the PPE resin can vary widely, depending at least in part on the intended end-use for the PPE resin. The intrinsic viscosity (hereinafter “I.V.”) of the PPE resin is typically in the range of about 0.08-0.60 dl./g., as measured in chloroform at 25° C. by the methods described in the procedure below.
Verify bath temperature is at 25° C.±0.1° C.
All I.V. measurement should be done on PPE resin that has been dried in a vacuum oven for a period of at least 1 hour at a temperature of 125° C. Let powder cool about 5 minutes prior to weighing.
Using an analytical balance, place
Devanathan Narsi
Guo Hua
Lewis Charles
General Electric Company
Truong Duc
LandOfFree
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