AN ADDITIVE COMPOSITION FOR INCREASING THE CONDUCTIVITY OF AN ORGANIC POLYMER, AN ACTIVE HYDROGEN-CONTAINING COMPOSITION CONTAINING THE ADDITIVE COMPOSITION, AND AN ORGANIC POLYMER COMPOSITION CONTAINING THE ADDITIVE COMPOSITION

Abstract: This additive composition is characterized by comprising (a) a nonvolatile ionizable metal salt and (b) an enhancer which is a salt or ester of a carboxylic acid in which said metal salt is soluble, which enhancer increases the conductivity of an organic polymer containing said ionizable salt, but which does not itself substantially increase the conductivity of said organic polymer in the substantial absence of said ionizable salt.

Description: AN ADDITIVE COMPOSITION FOR INCREASING THE CONDUCTIVITY OF AN ORGANIC POLYMER, AN ACTIVE HYDROGEN-CONTAINING COMPOSITION CONTAINING THE ADDITIVE COMPOSITION, AND AN ORGANIC POLYMER COMPOSITION CONTAINING THE ADDITIVE COMPOSITION This invention relates to an additive composi¬ tion for increasing the conductivity of an organic polymer. Most organic polymers are poor conductors of electricity÷ As such, they cannot be satisfactorily used without modification in applications which require a conductive or semiconductive material, such as static dissipative materials. Due to their beneficial properties such as low cost, easy processability, good strength and light weight, it is often desirable to substitute polymeric materials into applications which in the past required metals or other materials. Accordingly, it has been attempted to prepare semiconductive or conductive polymers. It is known, for example, to incorporate con¬ ductive fibers, particulates or powders into a polymer in order to increase its conductivity. Although good conductivity can be achieved in this manner, the high loadings of filler material (generally 20 percent or more) needed to obtain such conductivity greatly alter the properties of the polymer, often making it unsuit¬ able for its desired purpose. In addition, such highly filled polymers are often much more expensive than the unfilled polymer. Yet another problem encountered with certain such fillers, especially fibers, is they often break, oxidize or otherwise lose their effectiveness over time. It is also known to treat the surfaces of polymers with amines or quaternary ammonium compounds to render them antistatic. However, such treatments are often removed from the polymer during its -normal use, causing the polymer to lose its antistatic proper¬ ties. Another approach has been to incorporate ionic salts into a polymer to increase its conductivity. For example, in Dupon et al. J^ Elec. Chem. Soc. 128:715 (1981) ' it is taught to incorporate salts such as sodium thiocyanate into a high molecular weight poly(ethylene oxide) to increase its conductivity. French Patents 2,442,513-4 demonstrate the dissolution of mixed alkaki metal thiocyanate salts into poly(alkylene oxide) polymers for the same reason. In these references, the concen¬ tration of salt is generally at least 5 weight percent, and is preferably as high as 25 weight 'percent. Such a high level of salt often imparts undesirable properties -2- to the polymer, such as sensitivity to water. When such levels of salts are employed in a flexible polyurethane foam, the foam often fails, prunes or collapses due to the formation of undesired closed cells. Although inclusion of these salts has improved the conductivity of the polymers,_ it would be desirable from the standpoint of utility and cost to further increase the conductivity of the polymer while minimizing the salt content. This invention is an additive composition for increasing the conducitivity of an organic polymer characterized by comprising (a) a nonvolatile ionizable metal salt and (b) an enhancer which is a salt or ester of a carboxylic acid in which said metal salt'is soluble, which enhancer increases the conductivity of an organic polymer containing said ionizable salt, but-which does not itself substantially increase the conductivity of said organic polymer in the substantial absence of said ionizable salt. This invention is also an active hydrogen- containing composition comprising a polyahl or mixture of polyahls characterized by having dispersed therein the additive composition of this invention. This invention is additionally an organic polymer composition characterized by comprising an organic polymer having dispersed therein the additive composition of this invention. -3- It has been found that by employing an ioniz¬ able metal salt and an enhancer as described herein, a substantial increase in the conductivity of an organic polymer is obtained. The additive of this invention comprises, as one component, an ionizable salt. Said salt is one con¬ taining at least one metal cation which is in ionic association with at least one anion. By ionizable, it is meant that the salt is one which provides mobile ions in the presence of an electric field. The cation can be any metal which forms an ionizable salt with one or more anions, including those in Row 2, groups IA and IIA; Row 3, groups IA, IIA and IIIA; Row 4, groups IA-IVA and IB-VIII B; Rows 5 and 6, groups IA-VA and.IB-VIII B; and the lanthanide series in the Periodic Table of the Elements. Preferably, the metal is an alkali metal, an alkaline earth metal, Co, Ni, Fe, Cu, Cd, Zn, Sn, Al or Ag. The anion is any which forms an ionizable salt with the metal cation. The anion is advantageously the conjugate base of an inorganic acid or a C 2 -C 4 carboxylic acid. Suitable ions include, for example, the halides, ' i.e. F~, Cl~, Br " , and I~; NO 3 , SCN " , S0 4 ~ , HS0 4 , S0 3 ~, HSO 3 , Clθ , C0 3 " , P0 4 " , H 2 P0 4 , HP0 4 " , Pθ 3 -, HPO 3 " , H 2 Pθ 3 , acetate, tetraorganoboride, particularly tetraalkyl and tetraphenylboride. Of these, the halides, especially Cl , Br and I~; SCN~; the tetraorganoborides and acetates are preferred on the basis of generally better performance. Most preferred are SCN~ and tetraphenylboride ion, which are less reactive with metals, water or other materials which are often present in the polymer or come in contact with the polymer than are most other anions. Exemplary ionizable salts include, for example, zinc chloride, copper chloride, cobalt chloride, tin chloride, lithium chloride, iron chloride, magnesium chloride, potassium iodide, sodium iodide, lithium nitrate, cobalt nitrate, sodium acetate, cadmium acetate, zinc acetate, antimony trifluoride, sodium thiocyanate, lithium thiocyanate, potassium thiocyanate, sodium tetraphenyl¬ boride, and potassium tetraphenylboride. Most preferred are the alkali metal thiocyanate salts and tetraphenyl- boride salts. Another critical component of the additive is an enhancer. The enhancer comprises a salt or ester of a carboxylic acid in which the metal salt is soluble or dispersible and which does not substantially increase the conductivity of the polymer in the absence of the ionizable salt, but substantially increases the conduct¬ ivity of the polymer containing the ionizable salt. The enhancer is considered not to substantially increase the conductivity of a polymer in the absence of an ionizable salt if the conductivity of the polymer containing the enhancer is not more than 100 times that of the polymer alone, if the polymer containing the enhancer (but no ionizable salt) is too nonconductive to be measured for static dissipation according to the test described herein, or if the polymer containing the enhancer (but no ionizable salt) dissipates 99 percent of an applied static charge in 60 seconds or greater. Suitable enhancers include salts or esters of an organic acid. Advantageously, said salt or ester contains from 6 to 30 carbon atoms. Preferably, the -5- salt is one of a C 6 -C 30 carboxylic acid represented by the structure. O wherein M is a metal ion, n is a number representing the valence of the metal ion and R is an organic radical containing from 5 to 29 carbon atoms. The group R advantageously is a C 8 -C 22 , prefer- ably C 12 -C 22 aliphatic hydrocarbyl group. More preferably, the salt is a fatty acid salt, and is most preferably an alkali metal salt of a fatty acid. Suitable as the salt of a C 6 - 30 carboxylic acid are, for example, sodium oleate, potassium oleate, sodium stearate, potassium stearate, sodium laurate, potassium laurate, and sodium linoleate. Suitable esters include those represented by the structure O R (-C-OR 1 ) m (ID wherein each R 1 is independently an inertly substituted organic group, m is a number from 1 to 3, preferably 2, and R 2 is an inertly substituted organic radical containing from 4 to 29, preferably from 4 to 10, carbon atoms. Preferred are esters of dicarboxylic acids having from 6 to 20 carbon atoms. The group R 2 can be aliphatic, cycloaliphatic, aromatic, aliphatic-substituted aromatic, or aromatic- substituted aliphatic. Preferably, however, the group R 2 is an inertly substituted aliphatic hydrocarbyl group or an inertly substituted aromatic group. By "inertly substituted", it is meant that the group or molecule referred to contains no substitu- ent groups which interfere with the enhancing function of the group or molecule, undesirably reacts with the polymer in which it is employed, with other components therein, or significantly interferes with the preparation of such polymer its subsequent processing, or its proper- ties. Suitable inert substitutent groups which may be present in the enhancer include, for example, ester, ketone, ether or carboxylic acid groups, aromatic groups, tertiary amine groups, carbon-carbon double bonds, or halogen. The enhancer may, if desired, contain a func- tional group such as an isocyanate group or hydroxyl group which can react with the polymer to bond the enhancer to the polymer network. When R 2 is an aliphatic hydrocarbyl group, it preferably contains from 5 to 21 carbon atoms, and more preferably from 5 to 11, carbon atoms, when the acid is monofunctional (i.e. m is 1) and from 4 to 20, preferably from 4 to 10, carbon atoms when the acid is difunctional (i.e. m is 2). In such case, the carboxylic acid is preferably a fatty acid. When the group R 2 is an inertly substituted aromatic group it advantageously contains one or more aromatic rings which may contain aliphatic side chains. Preferably, when R 2 is an aromatic group, it contains from 6 to 22 carbon atoms, more preferably from 6 to 12 carbon atoms (including those in side chains, if any). Most preferably, the group R 2 , when aromatic, is a phenyl group and the ester is one of benzoic, phthalic or tere- phthalic acid. When a diester such as represented in - - Structure III is used, the R 2 groups are most preferably inertly substituted aromatic groups as described in this paragraph. The group R 1 is advantageously an inertly sub- stituted organic group. Preferably the group R 1 is an inertly substituted hydrocarbyl or poly(oxyalkylene) group having from 2 to 20, preferably from 2 to 10, carbon atoms. More preferably, R 1 is a C 2 - 4 alkyl group or a polymer of ethylene oxide, propylene oxide, butylene oxide or mixture thereof having from 2 to 10 carbon atoms. Such polymer may be hydroxyl-terminated but is more prefer¬ ably terminated with an alkyl group. Also suitable are diesters represented by the structure 0 0 2 ιι 3 it 2 R -C-O-R -O-C-R wherein each R 2 is independently an organic radical as defined hereinbefore and R 3 is an inertly substituted organic diradical. The group R 3 is an inertly substituted organic diradical. Advantageously, the group R 3 is an alkylene diradical, -a alkylene ether diradical or polyether diradi¬ cal. The group R 3 advantageously contains from 2 to 20, preferably from 2 to 10, carbon atoms. Exemplary esters include, ' for example, methyl stearate, ethyl stearate, methyl oleate, ethyl oleate, n-butyl oleate, t-butyl oleate, methyl laurate, ethyl laurate, methyl linoleate, ethyl linoleate, methyl pal itate and other fatty acid esters, methyl phthalate, ethyl phthalate, methoxy ethyl phthalate, ethoxyethyl- phthalate, di(ethoxyalkyl) hthalate, di(butoxyethyl) phthalate, di(butoxyethoxyethy1)phthalate, di(butoxyethyl)- aliphate, dioctyl phthalate, di(butoxyethoxyethyl)adipate, di(butoxyethyl) glutinate, di(butoxyethyl)sebacate, and dibutylterephthalate. Also suitable are diesters prepared from a hydroxyl terminated polyether and two moles of phthalic or terephthalic acid. The additive of this invention can contain the aforementioned ionizable salt and enhancer in any ratio such that when an effective amount of the additive is incorporated into a polymer, the conductivity of the polymer is greater than that of a like polymer containing only the ionizable salt. Generally, the additive contains from 0.5 to 100, preferably from 1 to 25, moles of said enhancer per mole of ionizable salt. The additive of this invention may be added to an organic polymer as a mixture of the foregoing com¬ ponents, or each of said component may be added separately to the polymer. The organic polymer may be any into which the antistatic additive can be dispersed. The ability to disperse the antistatic additive is to a large extent dependent on the compatibility of the enhancer and the organic polymer. Accordingly, it is generally desirable to select the organic polymer and the enhancer together so that the two components are compatible. Alternatively, the antistatic agent and the organic polymer can be compatibilized by use of a cosolvent or other material which compatibilize the polymer and the antistatic agent. -9- Addition polymers and condensation polymers are useful herein as are either thermoplastic or thermo- setting polymers. Exemplary of the polymers that are useful herein are polyolefins such as polyethylene and polypropylene, polymers of conjugated dienes such as butadiene; poly(vinyl aromatics) such as polystyrene and poly(vinyl toluene); polycarbonates, acrylic resins such as polymers of acrylic and methacrylic acid and alkyl or hydroxylethyl esters thereof; polymers of vinyl chloride, vinylidene chloride or mixtures thereof; poly¬ esters; copolymers of ethylene with carbon monoxide or vinyl alcohol; and polyurethanes or other polymers based on an organic polyisocyanate. Blends, alloys and copolymers of the foregoing polymer are also useful. For the purpose of this invention the term polymer's based on organic polyisocyanates and "organic polyisocyanate polymers" are understood to mean those polymers which can be obtained by reaction of an organic polyisocyanate with an organic compound which contains at least two Zerewitinoff active hydrogen atoms, e.g. polycarbodiimides, polyisocyanurates, polyureas, poly- biurets, polyamides, polyallophanates or polyurethanes or polymers containing a mixture of urethane, urea, allophanate, biuret, amide, carbodiimide and/or isocyanurate groups, and any other polymer based on a polyisocyanate " . The process described here is particu¬ larly suitable for the production of polymers which contain urethane and urea groups prepared from a reaction mixture containing an organic polyisocyanate. All such polymers based on organic polyisocyanates are also referred to herein by the shorthand term "polyurethanes" . In the preparation of polyurethane foams con¬ taining the additive of this invention, said additive is advantageously present in a reaction mixture of a polyahl (defined hereinafter) and a polyisocyanate. Since in preparing such reaction mixture it is prefer¬ able to add all the components in as few streams as possible, it is generally preferred to premix the additive of this invention with the polyahl to form an active hydrogen-containing composition which is then reacted with the polyisocyanate. The term "polyahl" as used herein, includes any polyfunctional compound having at least two active hydrogen atoms. For the purposes of this invention, an active hydrogen moiety refers to a moiety containing a hydrogen atom which, because of its position in the molecule, displays significant activity according to the Zerewitnoff test described by Woller in the Journal of American Chemical Society, Vol. 49, page 3181 (1927). Illustrative of such active hydrogen moieties are -COOH, -OH, -NH 2 , -NH-, -CONH 2 , -SH and -CONH-. Typical polyahls include, for example, polyols, polyamines, polyamides, polymercaptans and polyacids. The additive of this invention may be added to the polyahl as a mixture of the ionizable salt and the enhancer in the desired proportions or preferably as a "concentrate" comprising the additive dissolved or dispersed in a polyahl or mixture thereof. In such "concentrate", the concentration of additive is somewhat higher than that normally present in the active hydrogen- containing composition which is reacted with the poly¬ isocyanate. Such concentrate normally contains from 0.5 to 50, preferably from 1 to 25, more preferably from 1 to 10, percent by weight of the ionizable salt, and a - - corresponding amount of enhancer. A "B-side" for preparing polyurethanes typically contains from 0.015 to 20, preferabl from 0.075 to 10, percent by weight of the ionizable salt. If desired, each component of the additive of this invention may be added individually to the polyahl. Sufficient of the additive of this invention is used to increase the conductivity of the product polymer. In general, the conductivity of the polymer is increased when the polymer contains from 0.01 to 10, preferably from 0.05 to 5, percent by weight of the ionizable salt. As stated hereinbefore, the polymer advantageously contains from 0.5 to 100, preferably from 1 to 25, moles of the enhancer per mole of the ionizable salt. In making a polyurethane polymer containing the additive of this invention, the polyahls, polyiso¬ cyanates, and other components, if any, are those con¬ ventionally employed in the preparation of polyurethane polymers. Suitable polyahls include polyether polyols, polyester polyols, polyhydroxyl-containing phosphorous compounds, hydroxyl-terminated acetal resins, hydroxyl terminated amines and polyamines, the corresponding amine- terminated polyether and/or polyester polyols, the so- called polymer or copolymer polyols which comprise a dispersion of an addition polymer as copolymer in a continu¬ ous polyahl phase, as well as other active hydrogen- containing compounds which are known to be useful in the preparation of polyurethane polymers. Examples of these and other suitable polyahls are described ' more fully in U.S. Patent -4,394,491, particularly in columns 3-5 thereof. Suitable copolymer polyols include those described in U.S. Patent RE 29,118, RE 28,715 and 4,394,491. The molecular weight and functionality of the polyahl will depend on the properties desired in the polyurethanes. For example, the formation of flexible polyurethanes is favored by using relatively high equiva¬ lent weight (ie. 250-10,000) polyahl and/or one having relatively low (2-4) functionality. More rigid poly- urethanes are generally prepared from low equivalent weight (i.e. 50-250) polyahls and/or those having a high functionality (i.e. 3-16). Organic polyisocyanates which may be employed include aromatic,' aliphatic and cycloaliphatic polyiso- cyanates and combinations thereof. Representative of these types are diisocyanates such as, . for .example, -phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, hexamethylene-1,6-diisocyanate, tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyana hexahydrotolylene diisocyanate (and isomers), naphthylene-1, 5-diisocyanate, l-methoxyphenyl-2,4-diisocyanate, diphenyl- methane-4,4'-diisocyanate, 4,4'-biphenylene diisocyanate,3, 3 '-dimethoxy-4,4'-biphenyl diisocyanate, 3,3 '-dimethyl-4,4' diphenyl diisocyanate, and 3,3'-dimethyldiphenylpropane-4,- 4' ,4'-diisocyanate; the triisocyanate polymethylene poly- phenylisocyanate and tolylene-2,4,6-triisocyanate; and the tetraisocyanates such as 4,4'-dimethyldiphenyl ethane- 2,2' ,5,5'-tetraisocyanate. A crude polyisocyanate may also be used in the practice of the present invention, such as the crude toluene diisocyanate obtained by the phosgenation of a mixture of toluene diamines or the crude diphenylmethylene - - diisocyanate obtained by the phosgenation of crude diphenyl- methylenediamine. The preferred undistilled or crude isocyanates are disclosed in U.S. Patent 3,215,652. Especially preferred are methylene-bridged poly-phenyl polyisocyanates, due to their ability to crosslink the polyurethane. The isocyanate index (ratio of equivalents of isocyanates to equivalents of active hydrogens) is advantageously from 0.8 to 10, preferably from 1.0 to 4.0, more preferably from 1.0 to 1.25. Prepolymers or quasi-prepolymers of the fore¬ going polyisocyanates are also useful herein. In addition to the aforementioned polyahl, polyisocyanate and additive, various additional com¬ ponents may be employed in preparing the polyurethane polymer. The urethane reaction of polyisocyanate with a polyahl is advantageously carried out in the presence of an amount of urethane-type catalyst which is effective to catalyze the reaction of the polyahl with the polyiso- cyanate. Any suitable urethane catalyst may be used including tertiary amines, such as, for example, tri- ethylenediamine, N-methyl orpholine, N-ethyl morpholine, diethyl ethanolamine, N-coco morpholine, l-methyl-4- dimethylaminoethyl piperazine, 3-methoxy-N-dimethylpropyl amine, N,N-dimethyl-N' ,N'-methyl isopropyl propylenediamine, N,N-diethyl-3-diethylaminopropyl amine, and dimethyl benzyl amine. Other suitable catalysts are, for example, tin compounds such as stannous chloride, tin salts of carboxylic acids such as dibutyltin di-2-ethyl hexoate, as well as other organometallic compounds such as are disclosed in U.S. Patent 2,846,408. Catalyst for the trimerization of polyisocyanates, such as alkali metal alkoxides, may also optionally be employed herein. If a polyurethane foam is to be prepared, a blowing agent is employed. Such blowing agent comprises an inert gas, a low boiling organic liquid such as methyl- ene chloride or trichlorofluromethane, and/or a chemical blowing agent such as water, peroxides or azo compounds which react during the urethane polymerization reaction to generate a gas. In preparing a polyurethane foam, a wetting agent(s) or surface-active agent(s) is generally neces¬ sary since in the absence of same, the foams collapse or contain very large uneven cells. Numerous wetting agents have been found satisfactory. Nonionic surfactants and wetting agents are preferred. Of these, the nonionic surface-active agents prepared by the sequential addition of propylene oxide and then ethylene oxide to propylene glycol and the solid or liquid organosilicones have been found particularly desirable. Other surface-active agents which are operative, although not preferred, include polyethylene glycol ethers of long chain alcohols, tertiary amine or alkylolamine salts of long chain alkyl acid sulfate esters, alkyl sulfonic esters and alkyl arylsul- fonic acids. Other optional components include conventional additives such as, for example, pigments, fillers, flame retardant, stabilizers, and additional cell openers. Such catalysts, blowing agents, surfactants and other optional components are preferably blended with the polyahl before the reaction thereof with the polyisocyanate. The resulting polyurethane polymer is substanti¬ ally more conductive than a like polymer which does not contain the additive of this invention, or which- contains only one of the two critical components of said additive. In terms of conductivity, the additive of this invention, when incorporated into the polymer so that the polymer contains from 0.01 to 10 percent by weight of the ionizable salt, generally increases the conductivity of the polymer by about a factor of from 100 to 100 million (10 2 -10 9 ). The increased conductivity of the polymer con¬ taining the additive is also seen in its ability to dis¬ sipate a static charge. Although the polymer itself often is incapable of dissipating a static charge, the polymer containing the additive is able to rapidly dis- sipate static electricity. Often such polymer containing the additive can dissipate 99 percent of an applied static charge in a relatively short time, i.e. less than 50, more preferably less than 15, most preferably less than 2 seconds. Other methods are also useful to evaluate antistatic properties. In general, the advantages of this invention are obtained without significant adverse affects on the physical ' properties of the polymer. The polymer containing the additive is useful, for example, as a "solid electrolyte" for batteries, and for preparing antistatic packaging or shelving for materials such as electronic devices which are sensitive to or damaged by a rapid discharge of static electricity, or exposure to static electrical fields. This invention is also useful in making adhesives, elastomers, rigid, semirigid and flexible foams, films, and coatings. Such materials are useful to prepare engineering handling equipment for explosive materials, antistatic carpet and other flooring. The following examples are provided to illustrate the invention and not to limit the scope thereof. All parts and percentages are by weight unless otherwise indicated. Example 1 and Comparative Run A A flexible polyurethane foam Example 1 and 'Comparative Run A are prepared from the following base polyol formulation: Table I Parts by Weight Polyol 1 100 Water 3.6 Surfactant 2 0.8 Amine Catalyst 3 0.1 Tin Catalyst 4 0.2 1 A glycerine-initiated polyether polyol having an equivalent weight of about 1030. 2 BF-2370, a polysiloxane surfactant sold by Goldschmidt Chemical Corp. 3 Niax A-l, a tertiary amine catalyst sold by Union Carbide. 4 T-9, an organotin catalyst sold by M-T Chemicals. - - Example 1 is prepared by adding 1.5 parts ZnCl 2 and 10 parts of a terephthalic diester (an enhancer) having the structure to the base polyol. The additive contains 1.67 moles of terephthalic diester enhancer per mole of zinc chloride inionizable salt. Comparative Run A is prepared by adding 10 parts of the terephthalip diester to the base polyol. Example l.and Comparative Run A are each reacted with 47.9 parts (108 index) toluene diisocyanate to form a flexible polyurethane foam. The ability of each of these foams to dissipate a static charge is measured on an Electrotech Systems 406C static decay meter. The sample is conditioned at < 15 percent relative humidity for > 24 hours. A 5V x 3" < 2" (140 mm x 76 mm x 51 mm) sample is placed into the meter at 72°F (22.2°C) and charged to +5000 VDC at 14 percent relative humidity. The time required for this charge to dissipate 99 percent of the charge is measured. The shorter the time required, the better the ability of the foam to dissipate the charge, and " the more conductive the polymer. The charge on Example 1 is reduced to less than fifty volts in 1.36 seconds. When the test is repeated with an induced charge of (-)5000 VDC, 99 percent of the charge is dissipated in 1.68 seconds. By contrast, Comparative Run A is so unconductive it cannot be evaluated using the foregoing technique. Thus, it is seen that the enhancer itself does not signifi¬ cantly increase the conductivity of the polymer. However, the additive of this invention substantially increases the conductivity thereof. Example 2 and Comparative Run B Polyurethane foam Example 2 and Comparative Run B are prepared from the following components: Table II Parts By Weight Component Example 2 Comparative Run B Polyol 1 100 100 H 2 0 3.6 3.6 Surfactant 2 0.8 0.8 Amine Catalyst 3 0.2 . 0.1 Tin Catalyst 4 0.15 0.15 NaSCN 1.0 1.0 Di(butoxyethyl)phthal,ate 5 10.0 — Toluene diisocyanate 46.6 46.6 (108 index) 1 (108 index) 1 A glycerine-initiated polyether polyol having an equivalent weight of about 1030. 2 BF-2370, a polysiloxane surfactant sold by Goldschmidt Chemical Corp. 3 Niax A-l, a tertiary- amine catalyst sold by Union Carbide 4 T-9, an organotin catalyst sold by M-T Chemicals. 5 Plasthall DBEP, available from C. P. Hall. The additive contains 2.21 moles of DBEP enhancer per mole of NaSCN. Foam Example 2 is tested for static decay. It dissipates 99 percent of a +5000 volt charge in 0.51 seconds and 99 percent of -5000 volt charge in 0.32 seconds. Comparative Run B is similarly tested. It requires 2.18 seconds to dissipate 99 percent of a +5000 volt charge and 3.59 seconds to dissipate 99 percent of a -5000 volt charge. Thus, the addition of the di(butoxy- ethyl)phthalate decreases the time required to dissipate the charge by 77 percent for the +5000 volt charge and by 91 percent for the -5000 volt charge. Example 3 Polyurethane foam Example 2 is duplicated, except 10 parts of dioctylphthalate are used in place of the di(butoxyethyl)phthalate. This foam dissipates 99 percent of a +5000 volt charge in 0.97 seconds and 99 percent of a -5000 volt charge in 0.76 seconds. Example 4 and Comparative Run C Polyurethane foam Example 4 and Comparative Run C are prepared from the following components: Table III Parts by Weight Components Example 4 Comparative Run C Polyol 1 100 ' 100 H 2 0 3.6 3.6 Surfactant 2 0.8 0.8 Amine Catalyst 3 0.1 0.1 Tin Catalyst 4 0.2 0.2 NaSCN 1.0 — Di(butoxyethyl 5 phthalate) 10.0 — Toluene diisocyanate ,46.6 46.6 (108 index) (108 index) 1 A glycerine-initiated polyether polyol having an equivalent weight of about 1030. 2 BF-2370, a polysiloxane surfactant sold by Goldschmidt Chemical Corp. Niax A-l, a tertiary amine catalyst sold by Union Carbide. T-9, an organotin catalyst sold by M-T Chemicals. Plasthall DBEP, available from C. P. Hall. The air flow, density, tensile strength, tear strength, elongation, resiliency, compression set (90 percent) indention force deflection (IFD), percent hysteresis return, modulus, volume resistivity and static decay time are measured for each of Example 4 and Compara¬ tive Run C with results as indicated in the following Table. Table IV Parts by Weight Components Example 4 Comparative Run C Air Flow ftVmin 1 4.0 4.1 (m 2 /s) (0.0018. υ (0.00193) Density, pcf 1 (kg/m 3 ) 1.69 1.74 (27.1) (27.9) Tensile strength, psi 1 18.3 21.5 (kPa) (126) (148) tear strength lb/in 1 3.1 2.9 (N/m) (543) (508) elongation percent 1 260 240 resiliency percent 1 46 50 compression set, 90 percent 1 4.5 2.1 IFD 1 25 percent 28 43 • 65 percent ' 50 77 Return 25 percent 19 30 Percent Hysteresis return 1 67 68 Modulus 1 1.80 1.78 Volume resistivity2, ohms 1.5 x 1010 J 1012 Static decay 3 , sec 0.32 NM NM - not meaningful since the sample is too nonconductive to test. 1 ASTM D-3574 2 ASTM D-257 3 FTMS H 101, MIL-B-B1705B Method 4046 The foregoing data demonstrates that the inclu¬ sion of the additive of this invention does not signifi¬ cantly change most physical properties of the polymer in which it is contained, yet very substantially improves the conductivity thereof. Example 5 Polyurethane foam Example 5 is prepared from the following components Table V Parts by Weight Polyoll 107.8 H 2 0 3.6 Surfactant 2 1.0 Amine Catalyst3- 0.2 Tin Catalyst4 0.1 Sodium tetraphenylboride 0.2 Toluene diisocyanate 108 index di(butoxyethyl)phthalate5 5.0 1 A glycerine-initiated polyether polyol having an equivalent weight of about 1030. 2 BF-2370, a polysiloxane surfactant sold by Goldschmidt Chemical Corp. 3 Niax A-l, a tertiary amine catalyst sold by Union Carbide, 4 T-9, an organotin catalyst sold by M-T Chemicals. 5 Plasthall DBEP, available from C. P. Hall. The physical and static properties of this form are measured with results as indicated in Table VI. The additive contains 23.3 moles of DBEP enhancer per mole of sodium tetraphenylboride (sodium tetraphenyl- borate) ionizable alt. Table VI Properties of Foam Example 5 Air flow f 3 /min. (m3/s) 5.7 (0.00269) Density pcf (kg/m2) 1.78 (28.5) Tensile Strength psil (kPa) 17.5 (121) Tear Strength lb/inl (N/m) 3.1 (543) Elongation percentl 266 Resiliency percentl 53 Compression set, 90 percentl 3.3 IFD1 25 percent 32 65 percent 55 Return 25 percent 23 Percent Hysteresis 70 Modulusl 1.81 Static Decay, sec F 1 percent R.H. 70°F 0.4 13 percent R.H. 70°F 0.30 1ASTM D-3574 Example 6 and Comparative Run D Comparative Run D is prepared by melt-blending 50 grams of an ethylene carbon monoxide copolymer (15 weight percent CO) and 0.15 g sodium thiocyanate in a Haake-Buchler Rheocord System 40 blender for about 5 minutes at 200°C. Plaques are made from the mixture or a platen press heated to approximately 150°C. In like manner, 50 g of the ECO copolymer, and 10 g of a mixture containing 15.1 percent dipropylene glycol, 70.7 percent di(butoxyethoxyethyl)adipate 14.2 percent sodium thiocyanate are blended and formed into a plaque. This plaque is ' identified as Example 6. The additive contains 0.93 moles of di(butoxyethoxyethyl)- adipate enhancer per mole of sodium thiocyanate ionizable salt. Both Example 6 and Comparative Run D are evaluate for static dissipation according to the test described in Example 1, and for surface resistivity per ASTM D-257. The results are as indicated in Table VII. Table VII Example 6 Comparative Run D Static decay, sec 0.21 0.79 Surface Resistivity, ohms 2.84 x 1011 4.37 x 1012 Substantial improvement in both static decay and surface resistivity are seen with the invention.

Claims: - - CLAIMS 1. An additive composition for increasing the conductivity of an organic polymer characterized by comprising (a) a nonvolatile ionizable metal salt and (b) an enhancer which is a salt or ester of a carboxylic acid in which said metal salt is soluble, which enhancer increases the conductivity of an organic polymer containing said ionizable ' salt, but which does not itself substantially increase the conductivity of said organic polymer in the substantial absence of said ionizable salt. 2. The composition of ' Claim 1 characterized in that the enhancer is a salt or ester of a carboxylic acid containing from 6 to 30 carbon atoms. The composition of Claim 1 characterized in thhaatt tthhee eennlhancer is an ester of a C,-C_ n dicarboxylic acid 4. The composition of Claim 1 characterized by containing from 0.05 to 100 moles of the enhancer per mole of ionizable salt. 5. The composition of Claim 1 characterized in that the ionizable metal salt is an alkali metal tetra- phenyl boride. 6. An active hydrogen-containing composition ■comprising a polyahl or mixutre of polyahls characterized by having dispersed therein the additive composition of Claim 1. 7. The composition of Claim 6 characterized by containing from 0.5 to 50 percent by weight of the ionizable salt and from 0.5 to 100 moles of enhancer per mole of ionizable salt. 8. The composition of Claim 6 characterized by containing from 0.015 to 20 percent by weight of the ionizable salt. 9. An organic polymer composition characterized by comprising an organic polymer having dispersed therein the additive composition of Claim 1. 10. The composition of Claim 9 characterized by containing from 0.01 to 10 percent by weight of the ionizable salt and from 0.5 to 100 moles of the enhancer per mole of ionizable salt.

Inventors: KENNEDY EARL E, KNOBEL THOMAS M, WALKER MARY A, KENNEDY, EARL, E., KNOBEL, THOMAS, M., WALKER, MARY, A.
Applicants: DOW CHEMICAL CO, THE DOW CHEMICAL COMPANY
Application year: 1985
Main classification: C08G18
IPC codes: C08K3, C08K5, C08K13, H01B1, H01M6