SALT-MODIFIED ELECTROSTATIC DISSIPATIVE POLYMERS

Abstract: A low molecular weight polyether oligomer is modified with a salt during chain extending reaction of the polyether oligomer to form electrostatic dissipative polymer products such as polyurethanes, polyether amide block copolymers and polyether-ester block copolymers. The reaction product polymers exhibit relatively low surface and volume resistivities, and static decay times which are not too fast or too slow, yet are free of excessive amounts of extractable anions, particularly chlorine, nitrate, phosphate and sulfate. The electrostatic dissipative polymers can be blended with a variety of base polymers to form plastic alloys, which in turn can be utilized to form articles useful in the manufacture of electrostatic sensitive electronic devices.

Description: SALT-MODIFIED ELECTROSTATIC DISSIPATIVE POLYMERS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to electrostatic dissipative polymers, and in particular to salt-modified electrostatic dissipative polymers reacted from polyether oligomers. More particularly, the present invention is directed to salt-modified electrostatic dissipative polymers re- acted from polyether oligomers, which exhibit relatively low surface and volume resistivities, but which are generally free of excessive amounts of extractable anions. BACKGROUND ART The formation and retention of charges of static electricity on the surface of most plastics is well known. Plastic materials have a significant tendency to accumulate static electrical charges due to low electrical conductivity. This type of formation and retention of charges of static electricity can be problematic. The presence of static electrical charges on sheets of thermoplastic film, for example, can cause the sneets to adhere to one another thus making their separation for further processing more difficult. Moreover, the presence of static electrical charges causes dust to adhere to items packaged in a plastic bag for example, which may negate any sales appeal. The increasing complexity and sensitivity of microelectronic αevices makes the control of static discharge of particular concern to tnε electronics industry. Even a low voltage discharge can cause severe damage to sensitive devices The need to control static charge buildup and dissipation often requires the entire assembly environment for these devices to be constructed of partially conductive materials. It also may require that electrostatic protective packages, tote boxes, casings, and covers be made from conductive polymeric materials to store, ship, protect, or support electrical devices and equipment. The prevention of the buildup of static electrical charges which accumulate on plastics during manufacture or use has been accomplished by the use of various electrostatic dissipative (ESD) materials. These materials can be applied as a coating which may be sprayed or dip coated on the article after manufacture, although this method usually results in a temporary solution. Alternatively, these materials can be incorporated into a polymer used to make the article during processing, thereby providing a greater measure of permanence. However, the incorporation of these lower molecular weight electrostatic dissipative materials (antistatic agents) into the various matrix or base polymers has its own limitations. For example, the high temperatures required for conventional processing of most polymers may damage or destroy the antistatic agents, thereby rendering them useless with respect to their ESD properties. Moreover, many of the higher molecular weight ESD agents are not miscible with the matrix or base polymers employed. A large number of antistatic agents are also either catioπic or anionic in nature. These agents tend to cause the degradation of plastics, particularly PVC, and result in discoloration or loss of physical properties. Other antistatic agents have significantly lower molecular weights than the base polymers themselves. Often these lower molecular weight antistatic agents possess undesirable lubricating properties and are difficult to incorporate into the base polymer. Incorporation of the lower molecular weight antistatic agents into the base polymers often will reduce the moidabiiity of the base polymer because the antistatic agents can move to the surface of the plastic during processing and frequently deposit a coating on the surface of the molds, possibly destroying the surface finish on the articles of manufacture. In severe cases, the surface of the article of manufacture becomes quite oily and marbleized. Additional problems which can occur with lower molecular weight ESD agents are loss of their electrostatic dissipative capability due to evaporation, the development of undesirable odors, or promotion of stress cracking or crazing on the surface of an article in contact with the article of manufacture. One of the known lower molecular weight antistatic agents is a homopolymer or copolymer oligomer of ethylene oxide. Generally, use of the lower molecular weight polymers of ethylene oxide or poly- ethers as antistatic agents are limited by the above-mentioned problems relative to lubricity, surface problems, or less effective ESD properties. Further, these low molecular weight polymers can be easily extracted or abraded from the base polymer thereby relinquishing any electrostatic dissipative properties, and in some instances can also produce undesirably large amounts of unwanted extractable anions, and in particular chlorine, nitrate, phosphate, and sulfate anions. There are several examples of high molecular weight electrostatic dissipative agents in the prior art. In general, these additives have been high molecular weight polymers of ethylene oxide or a derivative thereof like propylene oxide, epichlorohydrin, glycidyl ethers, and the like. It has been a requirement that these additives be high molecular weight materials to overcome the problems mentioned above. However, these prior art ESD additives do not have a desired balance between electrical conductivity and acceptable low levels of extractable anions, in particular chlorine, nitrate, phosphate, and sulfate, which in turn can cause any manufactured articles containing such ESD additives to have unacceptable properties for some end uses. The present invention solves the problem of obtaining electro- static dissipative polymers or additives which exhibit relatively low surface and volume resistivities without unacceptably high levels of extractable anions, in particular chlorine, nitrate, phosphate, and sulfate anions. These electrostatic dissipative polymers in turn can be incorporated in base polymer compositions useful in the electronics industry without producing other undesirable properties in a finished article of manufacture. SUMMARY OF INVENTION The present invention relates to a polymer useful in forming a plastic alloy for use with an electronic device, the polymer includ- ing an effective amount of a salt, the salt being compatible with the polymer, the salt-modified polymer having a surface resistivity of from about 1 .0 X 1 0 6 ohm/square to about 1 .0 X 1 0 10 ohm/square as meas ¬ ured by ASTM D-257, and further the salt-modified polymer having less than about 8,000 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 1 ,000 parts per billion of said chlorine anions, less than about 1 00 parts per billion of said nitrate anions, less than about 6,000 parts per billion of said phosphate anions, and less than about 1 ,000 parts per billion of said sulfate anions. DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention relates to salt-modified electrostatic dissipative polymers reacted from low molecular weight polyether oli- gomers, wherein the polymers display relatively low surface and volume resistivities, yet generally are free of excessive levels of extractable anions. The low molecular weight polyether oligomer useful in the present invention is described and prepared as follows. The low molecular weight polyether oligomer useful in the present invention can comprise a homopolymer of ethylene oxide having a number average molecular weight of from about 200 to about 5000. The low molecular weight polyether oligomer can also comprise a co ¬ polymer of two or more copolymerizable monomers wherein one of the monomers is ethylene oxide and has a number average molecular weight from about 200 to about 20,000. Exemplary of the comonomers which can be copolymerized with ethylene oxide are: 1 ,2-epoxypropane(propylene oxide); 1 ,2- epoxybutane; 2,3-epoxybutane(cis & trans); 1 ,2-epoxypentane; 2,3- epoxypentane(cis & trans); 1 ,2-epoxyhextane; 2,3-epoxyhextane(cis & trans); 3,4-epoxyhextane(cis & trans); 1 ,2-epoxy heptane; 1 ,2- epoxydecane; 1 ,2-epoxydodecane; 1 ,2-epoxyoctadecane; 7-ethyl-2- methyl-1 ,2-epoxyundecane; 2,6,8-trimethyl-1 ,2-epoxynonane; styrene oxide. Other comonomers which can be used as comonomers with the ethylene oxide are: cyclohexene oxide; 6-oxabicyclo[3, 1 ,0]-hexane; 7-oxabicyclo[4, 1 ,0]heptane; 3-chloro-1 ,2-epoxybutane; 3-chloro-2,3- epxybutane; 3,3-dichloro-1 ,2-epoxypropane; 3,3,3-trichloro-1 ,2- epoxypropane; 3-bromo-1 -2-epoxybutane, 3-fluoro-1 ,2-epoxybutane; 3-iodo-1 ,2-epoxybutane; 1 , 1 -dichloro-1 -fluoro-2,3-epoxypropane; 1 - chloro-1 , 1 -dichloro-2,3-epoxypropane; and 1 , 1 , 1 ,2-pentachloro-3,4- epoxybutane. Typical comonomers with at least one ether linkage useful as comomoners are exemplified by: ethyl glycidyl ether; n-butyl glycidyl ether; isobutyl giycidyl ether; t-butyl glycidyl ether; n-hexyl glycidyl ether; 2-ethylhexyl glycidyl ehter; heptafluoroisopropyl glycidyl ether, phenyl glycidyl ether; 4-methyl phenyl glycidyl ether; benzyl glycidyl ether; 2-phenylethyl glycidyl ether; 1 ,2-dihydropentafluoroisopropyl glycidyl ether; 1 ,2-trihydrotetrafluoroisopropyl glycidyl ether; 1 , 1 - dihydrotetrafluoropropyl glycidyl ether; 1 , 1 -dihydranonafluoropentyl glycidyl ether; 1 , 1 -dihydropeπtadecafluorooctyl glycidyl ether; 1 , 1 - dihydropentadecafluorooctyl-α -methyl glycidyl ether; 1 , 1 - dihydropentadecafluorooctyl-β -methyl glycidyl ether; 1 , 1 - dihydropentadecafluorooctyl-α -ethyl glycidyl ether; 2,2,2-trifluoro ethyl glycidyl ether. Other comonomers with at least one ester linkage which are useful as comonomers to copolymerize with ethylene oxide are: gly- cidyl acetate; glycidyl chloroacetate; glycidyl butyrate; and glycidyl ste ¬ arate; to name a few. Typical unsaturated comonomers which can be polymerized with ethylene oxide are: allyl glycidyl ether; 4-vinylcyclohexyl glycidyl ether; α-terpinyl glycidyl ether; cyclohexenylmethyl glycidyl ether; p- vinylbenzyl glycidyl ether; allyphenyl glycidyl ether; vinyl glycidyl ether; 3,4- epoxy-1 -pentene; 4,5-epoxy-2-pentene; 1 ,2-epoxy-5,9- cyclododeca diene; 3,4-epoxy-1 -vinylchlohexene; 1 ,2-epoxy-5- cyclooctene; glycidyl acrylate; glycidyl methacrylate; glycidyl crotonate; glycidyl 4-hexenoate. Other cyclic monomers suitable to copolymerize with ethylene oxide are cyclic ethers with four or more member-ring containing up to 25 carbon atoms except tetrahydropyran and its derivatives. Exemplary cyclic ethers with four or more member-ring are oxetane (1 ,3-epoxide), tetrahydrofuran ( 1 ,5-epoxide), and oxepane ( 1 ,6-epoxide) and their derivatives. Other suitable cyclic monomers are cyclic acetals containing up to 25 carbon atoms. Exemplary cyclic acetals are trioxane, dioxo- lane, 1 ,3,6,9-tetraoxacycloundecane, trioxepane, troxocane, dioxepane and their derivatives. Other suitable cyclic monomers are cyclic esters containing up to 25 carbon atoms. Exemplary cyclic esters are beta-valerolactone, epsilon-caprolactone, zeta-enantholactone, eta-caprylactone, butyrolac- tone and their derivatives. The low molecular weight polyether oligomer prepared by the method detailed immediately above then can be reacted with a variety of chain extenders and modified with a selected salt to form the electrostatic dissipative polymer additive or antistatic agent of the present invention. For example, the polyether oligomer described immediately above can be reacted to form an electrostatic dissipative agent comprising a copolyether-ester polymer comprising one or more polyester blocks as well as one or more low molecular weight polyether oligomer blocks. The polyester block is generally made from an aromatic containing dicarboxylic acid or diester such as terephthalic acid, dimethyl terephthalate, and the like, with a diol generally containing from about 2 to about 1 0 carbon atoms. The low molecular weight polyether oligomer is generally made as described above. The polyether-ester block copolymers can be represented by the following formula: -(polyester-b-low molecular weight polyether oligomer) n . A preferred embodiment of the polyester-ether block copolymer comprises the reaction product of ethylene glycol, terephthalic acid or dimethyl terephthalate and polyethylene glycol. These and other examples of other polyester-ether copolymers which can be utilized are set forth in the Encyclopedia of Polymer Science and Engineering , Vol. 1 2, John Wiley & Sons, Inc., NY, NY, 1 988, pages 49-52, which is hereby fully incorporated by reference as well as U.S. Patent Nos. 2,623,031 ; 3,651 ,01 4; 3,763, 1 09; and 3,896,078. Alternatively, the low molecular weight polyether oligomer can be reacted to form an electrostatic dissipative agent comprising one or more polyamide blocks as well as one or more low molecular weight polyether oligomer blocks. Alternatively, the low molecular weight polyether oligomer may be reacted with the polyamide in the presence of a diacid to form a polyether ester amide having the recur- ring formula: -(C( = O-A-C( = 0)-O-B-O) n - where A is the polyamide and B is the low molecular weight polyether oligomer. Further information on this polymer can be found in U.S. Patent No. 4,332,920, incorporated herein by reference. Examples of commercially available compositions containing the low molecular weight polyether oligomers which can be modified with salt as contemplated by the present invention, include Stat-Rite ® C-2300 ESD agents, available from the B.F. Goodrich Company; Pe- bax MX 1 074, and Pebax 401 1 MA, available from Eif Atochem Company, Engineered Polymers Division; and Hytrel 8099, Hytrel 8206, Hytrel 81 71 and Hytrel 3548, available from DuPont Company and Hydrin 200, available from Nippon Zeon. In a preferred embodiment of the present invention, the low molecular weight polyether oligomer can be reacted to form a polyurethane electrostatic dissipative agent, such as the Stat-Rite ® C-2300 ESD agent available from the B.F. Goodrich Company. More specifi- cally, the polyurethane electrostatic dissipative additive comprises the reaction of a hydroxyl terminated ethylene ether oligomer intermediate with a non-hindered diisocyanate and an extender glycol, where the oligomer can be a diethylene glycol-aliphatic polyester, or a polyethylene glycol. Referring first to the polyester intermediate, a hydroxyl terminated, saturated polyester polymer is synthesized by reacting excess equivalents of diethylene glycol with considerably lesser equivalents of an aliphatic, preferably an alkyl, dicarboxylic acid having four to ten carbon atoms where the most preferred is adipic acid. Other useful dicarboxylic acids include succinic, glutaric, pimelic, suberic, azelaic and sebacic acids. The most preferred polyester intermediate is polydiethylene glycol adipate. In accordance with this aspect of the present invention, excess moles of diethylene glycol are reacted with lesser moles of dicarboxylic acid at levels from about 5 mole percent to about 50 mole percent excess of glycol to provide a hydroxyl terminated polyester oligomer chain having an average molecular weight between about 500 to 5000 and preferably between about 700 and 2500. The short chain polyester oligomer contains repeating diethylene ether structures and comprises on an equivalent basis from about 1 .05 to 1 .5 equivalents of diethylene glycol co-reacted with one equivalent of dicarboxylic acid to produce the low molecular weight polyester oligomer intermediate. The high excess equivalents of diethylene glycol controls the molecular weight of the polyester oligomer preferably below 2500 and further assures a hydroxyl termi- nated linear polyester oligomer. The polyester oligomers synthesized by reacting the diethylene glycol with lesser equivalents of dicarbox ¬ ylic acid at temperatures of from about 300°F to 450°F in the absence or in the presence of an esterification catalyst such as stannous chloride for time sufficient to reduce the Acid No. to about zero. The hydroxyl terminated polyester oligomer intermediate is further reacted with considerably excess equivalents of non-hindered diisocyanate along with extender glycol in a so-called one-shot or simultaneous coreaction of oligomer, diisocyanate, and extender glycol to produce the very high molecular weight linear polyurethane having an average molecular weight broadly from about 60,000 to about 500,000, preferably from about 80,000 to about 1 80,000, and most preferably from about 100,000 to about 1 80,000. Alternatively, an ethylene ether oligomer glycol intermediate comprising a polyethylene glycol can be co-reacted with non-hindered diisocyanate and extender glycol to produce the high molecular weight, polyurethane polymer. Useful polyethylene glycols are linear polymers of the general formula H-(OCH 2 CH 2 )- n OH where n is the number of repeating ethylene ether units and n is at least 1 1 and between 1 1 and about 1 1 5. On a molecular weight basis, the useful range of polyethylene glycols have an average molecular weight from about 500 to about 5000 and preferably from about 700 to about 2500. Commercially available polyethylene glycols useful in this invention are typically designated as polyethylene glycol 600, polyethylene glycol 1 500, and polyethylene glycol 4000. In accordance with this invention, high molecular weight thermoplastic polyurethanes are produced by reacting together pref- erably in a one-shot process the ethylene ether oligomer glycol intermediate, an aromatic or aliphatic non-hindered diisocyanate, and an extender glycol. On a mole basis, the amount of extender glycol for each mole of oligomer glycol intermediate is from about 0.1 to about 3.0 moles, desirably from about 0.2 to about 2.1 moles, and prefera- bly from about 0.5 to about 1 .5 moles. On a mole basis, the high molecular weight polyurethane polymer comprises from about 0.97 to about 1 .02 moles, and preferably about 1 .0 moles of non-hindered di- isocyanate for every 1 .0 total moles of both the extender glycol and the oligomer glycol (i.e. extender glycol + oligomer glycol - 1 .0) . Useful non-hindered diisocyanates comprise aromatic non- hindered diisocyanates and include, for example, 1 ,4- diisocyanatobeπzene (PPDI) , 4,4'-methylene-bis (phenyl isocyanate) MDI), 1 , 5-πaphthalene diisocyanate (NDI), m-xylene diisocyanate (XDI), as well as non-hindered, cyclic aliphatic diisocyanates such as 1 ,4-cyclohexyl diisocyanate (CHDI), and H 12 MDI . The most preferred diisocyanate is MDI . Suitable extender glycols (i.e. chain extenders) are aliphatic short chain glycols having two to six carbon atoms and containing only primary alcohol groups. Preferred glycols include diethylene glycol, 1 ,3-propane diol, 1 ,4-butane diol, 1 ,5-pentane diol, 1 ,4-cyclohexane-dimethanol, hydroquinone di (hydroxyethyl) ether, and 1 , 6-hexane diol with the most preferred glycol being 1 ,4-butane diol . In accordance with the present invention, the hydroxyl terminated ethylene ether oligomer intermediate, the non-hindered diisocyanate, and the aliphatic extender glycol are co-reacted simultaneously in a one-shot polymerization process at a temperature above about 1 00°C and usually about 1 20°C, whereupon the reaction is exothermic and the reaction temperature is increased to about 200°C to above 250°C. In accordance with a key feature of the present invention, an effective amount of a salt, salt complex or salt compound formed by the union of a metal ion with a non-metallic ion or molecule is added during the one-shot polymerization process. While the exact mechanism of attachment and/or attraction of the salt to the ESD polymer reaction product is not completely understood, the salt unexpectedly improves the surface and volume resistivities of the resulting polymer without the presence of unacceptably high levels of extractable ani ¬ ons. Moreover, the static decay times remain in an acceptable range, that is, the times are not too fast or too slow. Examples of salts use- ful in the subject invention include: LiCI0 4 , LiN(CF 3 S0 2 ) 2 , LiPF 6 , LiAsF 6 , Lil, LiBr, LiSCN, LiS0 3 CF 3 , LiN0 3 , LiC(S0 2 CF 3 ) 3 , Li 2 S, and LiMR 4 where M is Al or B, and R is a halogen, alkyl or aryl group. The preferred salt is Li N(CF 3 S0 2 ) 2 , which is commonly referred to as lith- ium trifluoromethane sulfonimide. The effective amount of the selected salt added to the one-shot polymerization is at least about 0.1 0 parts based on 1 00 parts of the polymer, desirably at least about 0.25 parts and preferably at least about 0.75 parts. In accordance with another important feature of the present invention, it has been discovered that the amount of salt utilized can be unexpectedly lowered when the salt is added in conjunction with an effective amount of a co-solvent. Examples of co-solvents suitable for this purpose include ethylene carbonate, propylene carbonate, dimethyl sulfoxide, tetramethylene sulfone, tri- and tetra ethylene glycol dimethyl ether, gamma butyrolactone, and N-methyl-2-pyrrolidone. Ethylene carbonate is preferred. Although the addition of one of the co-solvents is optional, in some applications lower amounts of the salt may be desirable. The effective amount of co-solvent required to achieve the desired result of lower salt usage while still attaining the desired properties in the ESD polymer, is at least about 0.1 0 parts based on 1 00 parts of the polymer, preferably at least about 0.50 parts, and most preferably at least about 1 .0 parts. Thus, it is unexpectedly found that addition of the co-solvent together with a lowered amount of the salt synergistically lowers the surface and volume resis- tivities of the ESD polymer, without adversely affecting the presence of only relatively low amounts of extractable anions, in a manner similar to that which is observed when slightly higher amounts of the salt alone are added to the polymerization. The salt-modified electrostatic dissipative polymer of the present invention can be blended with a matrix or base polymer com ¬ prising a homopolymer or a copolymer of a polyvinyl chloride, chlorin ¬ ated polyvinyl chloride, copolymers of styrene and acrylonitrile, ter- polymers of styrene, acrylonitrile and diene rubber, copolymers of styrene and acrylonitrile modified with an acrylate elastomer, copolymers of styrene and acrylonitrile modified with ethylene propylene diene monomer rubber, polystyrene and rubber modified impact polystyrene, nylon, polycarbonate, thermoplastic polyesters including polybutylene terephthalate, polyethylene terephthalate and polyether-ester block copolymers, polyurethane, polyphenylene oxide, polyacetatal, polymethyl methacrylate, polypropylene, polyethylene, and polyether amide block copolymer. The preferred ratio of the ESD polymer agent or additive to the base polymer is about 25 parts of ESD additive based on 1 00 parts of the ESD additive/base polymer blend. The preferred base polymer is polyethylene terephthalate and is available from Eastman Chemical Products, Inc., of Kingsport, Tennessee. The above-described process for forming the salt-modified electrostatic dissipative polymer of the present invention, which can in turn be blended with base polymers for use in forming finished articles having properties which make the articles useful in the electronics industry, can be better understood by the following examples. EXAMPLES Example 1 The preferred salt-modified polyurethane ESD polymer additive of the present invention was prepared by chain extending a poly- ethylene glycol oligomer, in the manner described hereinabove. The salt was added during the one-shot polymerization of the polyethylene glycol, diisocyanate and the aliphatic extender glycol to form the polyurethane polymer, as also detailed hereinabove. For the sake of relative completeness, it should be noted that the only difference be- tween the polymers of Control X and Control Y, and of the modified samples 1 02-1 04 and 1 05-1 1 6, respectively, made therefrom, is that Control X was made from a single polyethylene glycol oligomer having an average molecular weight of 1 ,450, and Control Y was made from a pair of polyethylene glycol oligomers, one having an average molecular weight of 1 ,450 and the other having an average molecular weight of 3,350. The prepared polymers and salt and/or co-solvent- modified samples made therefrom then were analyzed according to ASTM D-257 for surface and volume resistivities, the results of which are set forth in Table I. The same samples also were measured for levels of certain undesirable extractable anions as set forth in Table II as well as for static decay times as set forth in Table III . The results show that surface resistivities in the range of from about 1 X1 0 7 to about 1 X 1 0 9 ohm/square and volume resistivities in the range of from about 1 X1 0 6 to about 1 X 1 0 9 ohm. cm were obtained by adding a salt during polymerization. These resistivities unexpectedly are significantly lower than the surface and volume resistivities of unmodified Controls X and Y. The results in Table I also show that when ethylene carbonate co-solvent alone is added to a control polymer (see sample ID 1 05) the resistivities actually increase. However, when the same co-solvent is added in combination with the same or lower levels of the salt than the salt level used when the salt is added by itself, the significantly improved resistivities are unexpectedly again observed. Also unexpectedly, and as shown in Table II, the amount of extract- able anions remained low in the salt-modified samples 1 02-1 04 of Control Polymer X, which itself exhibits low levels of the listed extractable anions. Surprisingly, the addition of Li-TFMSA salt alone and the salt together with ethylene carbonate co-solvent to samples 1 08- 1 1 6 of Control Polymer Y, which itself exhibits relatively high levels of the listed anions, significantly lowers the levels of the individually listed extractable anions as well as the grand total amount of all four anions in samples 1 08-1 1 6, over those levels found in Control Poly- mer Y. Finally, static decay times shown in Table III fell within a range which was not too fast or too slow, of from about 1 X 10 "1 seconds to about 2.5 x 1 0 ' 1 seconds. TABLE I SURFACE AND VOLUME RESISTIVITY OF STATIC DISSIPATIVE POLYURETHANE POLYMERS *Parts of salt based on 100 parts of polymer. Li-TFMSA = Lithium - trifluorometliane sulfinimide Eth. Carb. = Ethylene Carbonate TABLE II EXTRACTABLE ANIONS* (nanograms/centimeter 2 (parts per billion) OF EXTRACTED COMPOUND) FROM STATIC DISSIPATIVE URETHANE POLYMER * Measured by placing an 8 centimeter square, 40 mil thickness sample of the polyurethane polymer, in 10 ml of deionized water, then heating for I hour at 85°C ** Parts of salt based on 100 parts of polymer *** Of all four anions Li-TFMSA = Lithium - tπfluoro ethane sulfinimide Eth Carb = Ethylene Carbonate TABLE III STATIC DECAY TIMES* (in seconds) at 1000 V (51 % relative humidity) AND 5000 V (1 1.5% relative humidity) OF STATIC DISSIPATIVE URETHANE POLYMER Measured according to FTMS 1001 C for 5000 V values, an measurements at 1000 V were with charged plate monitor. ** Parts of salt based on 100 parts of polymer. Li-TFMSA = Lithium - trifluoromethane sulfinimide Eth. Carb. = Ethylene Carbonate While in accordance with the Patent Statutes, the best mode and preferred embodiments have been set forth, the scope of the invention is not limited thereto, but rather by the scope of the attached claims.

Claims: WHAT IS CLAIMED IS: 1 . A polymer useful in forming a plastic alloy for use with an electronic device, said polymer including: an effective amount of a salt, said salt being compatible with the polymer, said salt-modified polymer having a surface resistivity of from about 1 .0 X 1 0 5 ohm/square to about 1 .0 X 1 0 10 ohm/square as measured by ASTM D-257, and further said polymer having a volume resistivity of from about 1 .0 x 1 0 6 ohm-centimeter to about 1 .0 x 1 0 10 ohm-centimeter as measured by ASTM D-257. 2. The polymer of Claim 1 , in which said polymer has less than about 8,000 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 1 ,000 parts per billion of said chlorine anions, less than about 1 00 parts per billion of said nitrate anions, less than about 6,000 parts per billion of said phosphate anions, and less than about 1 ,000 parts per billion of said sulfate anions. 3. The polymer of Claim 2, in which said polymer has less than about 7,200 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 700 parts per billion of said chlorine anions, less than about 90 parts per billion of said nitrate anions, less than about 5,700 parts per billion of said phosphate anions, and less than about 750 parts per billion of said sulfate anions. 4. The polymer of Claim 3, in which said polymer has less than about 6,200 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 350 parts per billion of said chlorine anions, less than about 75 parts per billion of said nitrate anions, less than about 5,350 parts per billion of said phosphate anions, and less than about 450 parts per billion of said sulfate anions. 5. The polymer of Claim 1 , in which said polymer has a surface resistivity of from about 1 .0 X 1 0 6 to about 1 .0 X 1 0 9 . 6. The polymer of Claim 5, in which said polymer has a surface resistivity of from about 1 .0 X 1 0 7 to about 1 .0 X 10 8 . 7. The polymer of Claim 1 , in which said polymer has a volume resistivity of from about 1 .0 x 1 0 6 to about 1 .0 x 1 0 9 . 8. The polymer of Claim 7, in which said polymer has a volume resistivity of from about 1 .0 x 1 0 7 to about 1 .0 x 1 0 8 . 9. The polymer of Claim 1 , in which said effective amount of said salt is at least about 0.1 parts based on 1 00 parts of said polymer. 1 0. The polymer of Claim 9, in which said effective amount of said salt is at least about 0.25 parts. 1 1 . The polymer of Claim 1 0, in which said effective amount of said salt is at least about 0.75 parts. 1 2. The polymer of Claim 1 , in which said polymer includes an effective amount of a co-solvent. 1 3. The polymer of Claim 1 2, in which said effective amount of said co-solvent is at least about 0.1 parts based on 1 00 parts of said polymer. 1 4. The polymer of Claim 1 3, in which said effective amount of said co-solvent is at least about 0.5 parts based on 1 00 parts of said polymer. 1 5. The polymer of Claim 14, in which said effective amount of said co-solvent is at least about 1 part based on 1 00 parts of said polymer. 1 6. The polymer of Claim 1 2, in which said co-solvent is selected from the group comprising ethylene carbonate, propylene carbonate, dimethyl sulfoxide, tetramethylene sulfone, tri- and tetra-ethylene glycol dimethyl ether, gamma butyrolactone, and N-methyl-2-pyrrolidone. 1 7. The polymer of Claim 1 6, in which said co-solvent is ethylene carbonate. 1 8. The polymer of Claim 1 , in which said salt is selected from the group comprising lithium trifluoromethane sulfoπimide, LiCI0 4 , LiPF 6 , LiAsF 6 , Lil, LiBr, LiSCN, LiS0 3 CF 3 , LiN0 3 , LiC(S0 2 CF 3 ) 3 , Li 2 S, and LiMR d where M is Al or B, and R is a halogen, alkyl or aryl group. 1 9. The polymer of Claim 1 8, in which said salt is lithium trifluoromethane sulfonimide. 20. The polymer of Claim 1 , in which said polymer is the reaction product of a chain extended polyether oligomer. 21 . The polymer of Claim 20, in which said polymer is selected from the group comprising thermoplastic polyurethane, polyether amide block copolymer, and polyether-ester block copolymers. 22. The polymer of Claim 21 , in which said polymer is thermoplastic polyurethane. 23. The polymer of Claim 1 , in which said polymer has a static decay time at 1 000 V and 51 percent relative humidity of from about 1 .0 x 1 0 "1 to about 2.5 x 10 "1 as measured using a charged plate monitor; and in which said polymer has a static decay time at 5000 V and 1 1 .5 percent relative humidity of from about 1 .0 x 10 "1 to about 2.5 x 10 "1 as measured by FTMS 1 001 C. 24. A polymer useful in forming a plastic alloy for use with an electronic device, said polymer including: an effective amount of a salt, said salt being compatible with the polymer, said salt-modified polymer having a surface resistivity of from about 1 .0 X 1 0 6 ohm/square to about 1 .0 X 1 0 10 ohm/square as measured by ASTM D-257, and further said salt-modified polymer having less than about 8,000 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 1 ,000 parts per billion of said chlorine anions, less than about 1 00 parts per billion of said nitrate anions, less than about 6,000 parts per billion of said phosphate anions, and less than about 1 ,000 parts per billion of said sulfate anions. 25. The polymer of Claim 24, in which said polymer has less than about 7,200 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 700 parts per billion of said chlorine anions, less than about 90 parts per billion of said nitrate anions, less than about 5,700 parts per billion of said phosphate anions, and less than about 750 parts per billion of said sulfate anions. 26. The polymer of Claim 25, in which said polymer has less than about 6,200 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 350 parts per billion of said chlorine anions, less than about 75 parts per billion of said nitrate anions, less than about 5,350 parts per billion of said phosphate anions, and less than about 450 parts per billion of said sulfate a ions. 27. The polymer of Claim 24, in which said polymer has a volume resistivity of from about 1 .0 X 1 0 6 ohm-centimeter to about 1 .0 X 1 0'° ohm-centimeter as measured by ASTM D-257. 28. The polymer of Claim 27, in which said polymer has a volume resistivity of from about 1 .0 x 1 0 6 to about 1 .0 x 1 0 9 . 29. The polymer of Claim 28, in which said polymer has a volume resistivity of from about 1 .0 x 1 0 7 to about 1 .0 x 1 0 8 . 30. The polymer of Claim 24, in which said polymer has a surface resistivity of from about 1 .0 X 1 0 δ to about 1 .0 X 1 0 9 . 31 . The polymer of Claim 30, in which said polymer has a surface resistivity of from about 1 .0 X 1 0 7 to about 1 .0 X 1 0 8 . 32. The polymer of Claim 24, in which said effective amount of said salt is at least about 0.1 parts based on 1 00 parts of said polymer. 33. The polymer of Claim 32, in which said effective amount of said salt is at least about 0.25 parts. 34. The polymer of Claim 33, in which said effective amount of said salt is at least about 0.75 parts. 35. The polymer of Claim 24, in which said polymer includes an effective amount of a co-solvent. 36. The polymer of Claim 35, in which said effective amount of said co-solvent is at least about 0.1 parts based on 1 00 parts of said polymer. 37. The polymer of Claim 36, in which said effective amount of said co-solvent is at least about 0.5 parts based on 1 00 parts of said polymer. 38. The polymer of Claim 37, in which said effective amount of said co-solvent is at least about 1 part based on 1 00 parts of said poly- mer. 39. The polymer of Claim 35, in which said co-solvent is selected from the group comprising ethylene carbonate, propylene carbonate, dimethyl sulfoxide, tetramethylene sulfone, tri- and tetra-ethylene glycol dimethyl ether, gamma butyrolactone, and N-methyl-2-pyrrolidone. 40. The polymer of Claim 39, in which said co-solvent is ethylene carbonate. 41 . The polymer of Claim 24, in which said salt is selected from the group comprising lithium trifiuoromethane sulfonimide, LiCI0 4 , LiPF 6 , LiAsF 6 , Lil, LiBr, USCN, LiS0 3 CF 3 , LiN0 3 , LiC(S0 2 CF 3 ) 3 , Li 2 S, and LiMR 4 where M is Al or B, and R is a halogen, alkyl or aryl group. 42. The polymer of Claim 41 , in which said salt is lithium trifiuo ¬ romethane sulfonimide. 43. The polymer of Claim 24, in which said polymer is the reaction product of a chain extended polyether oligomer. 44. The polymer of Claim 43, in which said polymer is selected from the group comprising thermoplastic polyurethane, polyether amide block copolymer, and polyether-ester block copolymers. 45. The polymer of Claim 44, in which said polymer is thermo- plastic polyurethane. 46. The polymer of Claim 24, in which said polymer has a static decay time at 1 000 V and 51 percent relative humidity of from about 1 .0 x 1 0 "1 to about 2.5 x 10 "1 as measured using a charged plate moni- tor; and in which said polymer has a static decay time at 5000 V and 1 1 .5 percent relative humidity of from about 1 .0 x 1 0 "1 to about 2.5 x 1 0 "1 as measured by FTMS 1001 C. 47. A polymer useful in forming a plastic alloy for use with an electronic device, said polymer including: an effective amount of a salt, said salt being compatible with the polymer, so that said salt-modified polymer has a surface resistivity of from about 1 .0 X 1 0 6 ohm/square to about 1 .0 X 1 0 10 ohm/square as measured by ASTM D-257. 48. The polymer of Claim 47, in which said polymer has less than about 8,000 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 1 ,000 parts per billion of said chlo- rine anions, less than about 1 00 parts per billion of said nitrate anions, less than about 6,000 parts per billion of said phosphate anions, and less than about 1 ,000 parts per billion of said sulfate anions. 49. The polymer of Claim 48, in which said polymer has less than about 7,200 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 700 parts per billion of said chlorine anions, less than about 90 parts per billion of said nitrate anions, less than about 5,700 parts per billion of said phosphate anions, and less than about 750 parts per billion of said sulfate anions. 50. The polymer of Claim 49, in which said polymer has less than about 6,200 parts per billion total extractable anions measured from the group of all four of chlorine anions, nitrate anions, phosphate anions, and sulfate anions, and less than about 350 parts per billion of said chlorine anions, less than about 75 parts per billion of said nitrate anions, less than about 5,350 parts per billion of said phosphate anions, and less than about 450 parts per billion of said sulfate anions. 51 . The polymer of Claim 47, in which said polymer has a surface resistivity of from about 1 .0 X 1 0 6 to about 1 .0 X 1 0 9 . 52. The polymer of Claim 51 , in which said polymer has a surface resistivity of from about 1 .0 X 1 0 7 to about 1 .0 X 1 0 8 . 53. The polymer of Claim 47, in which said polymer has a volume resistivity of from about 1 .0 X1 0 6 ohm-centimeter to about 1 .0 X1 0 10 ohm-centimeter as measured by ASTM D-257. 54. The polymer of Claim 53, in which said polymer has a volume resistivity of from about 1 .0 x 10 6 to about 1 .0 x 1 0 9 . 55. The polymer of Claim 54, in which said polymer has a vol ¬ ume resistivity of from about 1 .0 x 1 0 7 to about 1 .0 x 1 0 8 . 56. The polymer of Claim 47, in which said effective amount of said salt is at least about 0.1 parts based on 1 00 parts of said polymer. 57. The polymer of Claim 56, in which said effective amount of said salt is at least about 0.25 parts. 58. The polymer of Claim 57, in which said effective amount of said salt is at least about 0.75 parts. 59. The polymer of Claim 47, in which said polymer includes an effective amount of a co-solvent. 60. The polymer of Claim 59, in which said effective amount of said co-solvent is at least about 0.1 parts based on 1 00 parts of said polymer. 61 . The polymer of Claim 60, in which said effective amount of said co-solvent is at least about 0.5 parts based on 1 00 parts of said polymer. 62. The polymer of Claim 61 , in which said effective amount of said co-solvent is at least about 1 part based on 1 00 parts of said polymer. 63. The polymer of Claim 59, in which said co-solvent is selected from the group comprising ethylene carbonate, propylene carbonate, dimethyl sulfoxide, tetramethylene sulfone, tri- and tetra-ethylene glycol dimethyl ether, gamma butyrolactone, and N-methyl-2-pyrrolidone. 64. The polymer of Claim 63, in which said co-solvent is ethylene carbonate. 65. The polymer of Claim 47, in which said salt is selected from the group comprising lithium trifiuoromethane sulfonimide, LiCI0 4 , LiPF 6 , LiAsF 6 , Lil, LiBr, LiSCN, LiS0 3 CF 3 , LiN0 3 , LiC(S0 2 CF 3 ) 3 , Li 2 S, and LiMR 4 where M is Al or B, and R is a halogen, alkyl or aryl group. 66. The polymer of Claim 65, in which said salt is lithium trifiuoromethane sulfonimide. 67. The polymer of Claim 47, in which said polymer is the reaction product of a chain extended polyether oligomer. 68. The polymer of Claim 67, in which said polymer is selected from the group comprising thermoplastic polyurethane, polyether amide block copolymer, and polyether-ester block copolymers. 69. The polymer of Claim 68, in which said polymer is thermoplastic polyurethane. 70. The polymer of Claim 47, in which said polymer has a static decay time at 1 000 V and 51 percent relative humidity of from about 1 .0 x 1 0 "1 to about 2.5 x 10 '1 as measured using a charged plate monitor; and in which said polymer has a static decay time at 5000 V and 1 1 .5 percent relative humidity of from about 1 .0 x 1 0 '1 to about 2.5 x 1 0 " 1 as measured by FTMS 1 001 C.

Inventors: ECKSTEIN YONA, RAVIKIRAN RAMAKRISHNA, ECKSTEIN, YONA, RAVIKIRAN, RAMAKRISHNA
Applicants: GOODRICH CO B F, THE B.F. GOODRICH COMPANY
Application year: 1999
Main classification: C08K3
IPC codes: C08K3, C08K5, C08L67, C08L75, C08L77, C08L101, H01L23