CA1049769A - Electrical insulation composition and covering conductors therewith - Google Patents
Electrical insulation composition and covering conductors therewithInfo
- Publication number
- CA1049769A CA1049769A CA228,101A CA228101A CA1049769A CA 1049769 A CA1049769 A CA 1049769A CA 228101 A CA228101 A CA 228101A CA 1049769 A CA1049769 A CA 1049769A
- Authority
- CA
- Canada
- Prior art keywords
- parts
- weight
- polyvinyl chloride
- weight per
- per
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
- H01B13/06—Insulating conductors or cables
- H01B13/14—Insulating conductors or cables by extrusion
- H01B13/148—Selection of the insulating material therefor
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K13/00—Use of mixtures of ingredients not covered by one single of the preceding main groups, each of these compounds being essential
- C08K13/02—Organic and inorganic ingredients
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
- C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L27/04—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
- C08L27/06—Homopolymers or copolymers of vinyl chloride
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
- H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
- H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
- H01B3/443—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins from vinylhalogenides or other halogenoethylenic compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
Abstract
Abstract of the Disclosure A priorly used three layer insulation covering for conductors forming a drop wire for connecting aerial distribution cables to subscriber's premises is replaced with a single layer of insulation which includes a reaction product of a mixture comprising polyvinyl chloride, a non-brominated unmodified epoxy resin, a plasticizer, a metallic stabilizer, a filler system, a flame retardant constituent and a carbon black constituent. The reaction mixture is extruded about a pair of conductors which have been preheated within a suitable temperature range. The tempera-ture of the conductors causes a reaction with the reaction mixture that has a reproducible permanent adhesion to the condutors.
Description
Background of the Invention 1. Field of the Invention This invention relates to an electrical insulation composition and methods of covering a conductor therewith and, more specifically, to an abrasion-resistan-t, insulating coating for electrical conductors and methods of producing electrical insulated conductors having a reproduceable adhesion of the insulation to the conductor.
2. Technical Considerations and Description of Prior Art Insulated electrical conductors, such as those employed in telephony applications, are often subjected to outdoor use or conditions under which the insulator is exposed to the deteriorating influences of sunlight, weather and abrasion. In the case of telephone drop wire, the familiar black overhead wire which brings telephone service to the home, it has been customary to employ extruded rubber insulation covered by a cotton serving jacketed with a neoprene compound of tire tread-like quality for protective purposes. Although such protective coatings have been in widespread use for many years and have proven satisfactory from most standpoints, there has long been a desire to develop an alternative, less expensive insulation.
Of course, any alternative covering must have specific properties to satisfy the requirements of this type of wire. For example, it is important that the plastic covered drop wire be covered with an insulation material which has adequate properties to withstand exposure to the elements, as well as adequate low temperature flexibility, impact resistance, and abrasion resistance.
., ~, .
, In the environment in which it is used, each end portion of the wire is inserted into a metallic clamp. One of the clamps is attached to a subscriber~s premises and the other one to a telephone pole prior to the electrical connection of the drop wire to wiring run inside the subscriber's premises and aerial distribution cables, respectively. At both the subscriber and the pole end of the drop wire, the retention of the wire in engagement with the clamp is effected by forces exerted by the clamp on the la insulation. If this is not transferred from the insulation to the conductors by the adhesion therebetween, the insulation may pull from the conductors and the entire weight of the drop wire would be held by -the terminal connection. This may very well lead to a disconnection of the circuit.
On the other hand, if the adhesion between the composition and the conductors is too great, there may be problems in attempting to strip the covering from the conductors. Too great an adhesion could require an excessive scraping activity tha-t would remove some of the metallic conduc-tive material from the surface portion of the conductors thereby increasing the electrical resistance and changing the conductivity thereof. Excessive scraping also unduly reduces the cross-sectional area of the wire or knicks it thereby reducing the strength properties of the wire to the detriment of its weight-supporting capability.
Drop wires have been manufactured in which coverings other than the three layer covering hereinbefore described have been used and which posses the requisite properties which includes optimum adhesion. These have generally involved the precoating of conductors with an ~'.
- .. ~ .. ... .... .. . , . .. . . -, ... ~ . , ~049769 adhesive followed by the extrusion of the final plastic insulation. This disadvantageously involves an extra manufacturing step and limits the line speed over that which can be obtained by applying a one layer covering over the conductors.
A composition of matter for producing a plastic covered drop wire without the necessity of precoating the conductors was disclosed and claimed in U. S. patent
Of course, any alternative covering must have specific properties to satisfy the requirements of this type of wire. For example, it is important that the plastic covered drop wire be covered with an insulation material which has adequate properties to withstand exposure to the elements, as well as adequate low temperature flexibility, impact resistance, and abrasion resistance.
., ~, .
, In the environment in which it is used, each end portion of the wire is inserted into a metallic clamp. One of the clamps is attached to a subscriber~s premises and the other one to a telephone pole prior to the electrical connection of the drop wire to wiring run inside the subscriber's premises and aerial distribution cables, respectively. At both the subscriber and the pole end of the drop wire, the retention of the wire in engagement with the clamp is effected by forces exerted by the clamp on the la insulation. If this is not transferred from the insulation to the conductors by the adhesion therebetween, the insulation may pull from the conductors and the entire weight of the drop wire would be held by -the terminal connection. This may very well lead to a disconnection of the circuit.
On the other hand, if the adhesion between the composition and the conductors is too great, there may be problems in attempting to strip the covering from the conductors. Too great an adhesion could require an excessive scraping activity tha-t would remove some of the metallic conduc-tive material from the surface portion of the conductors thereby increasing the electrical resistance and changing the conductivity thereof. Excessive scraping also unduly reduces the cross-sectional area of the wire or knicks it thereby reducing the strength properties of the wire to the detriment of its weight-supporting capability.
Drop wires have been manufactured in which coverings other than the three layer covering hereinbefore described have been used and which posses the requisite properties which includes optimum adhesion. These have generally involved the precoating of conductors with an ~'.
- .. ~ .. ... .... .. . , . .. . . -, ... ~ . , ~049769 adhesive followed by the extrusion of the final plastic insulation. This disadvantageously involves an extra manufacturing step and limits the line speed over that which can be obtained by applying a one layer covering over the conductors.
A composition of matter for producing a plastic covered drop wire without the necessity of precoating the conductors was disclosed and claimed in U. S. patent
3,579,608 issued on May 18, 1971 to John Be. DeCoste. In that application, there was shown an abrasion-resistant insulating coating which included a plasticized polyvinyl chloride in combination with a brominated epoxy resin that adhered directly to the surface of a heated conductor.
The conductors over which the plastic material is deposited are preheated within the range of 200 to 250C (392F to 482F) prior to entering the cross head die of an extruder.
In the aforementioned DeCoste patent, a PVC ~ ;
composition incorporating a brominated epoxy resin, a relatively expensive constituent, containing 18-48 percent bromine was used as the adhesive promoter. It was believed that the bromine was the functional portion of the epoxy resin that was essential to the attainment of the required adhesion. During the extrusion of the composition onto the preheated conductor, it was believed that hydrogen bromide was liberated which etched the conductor to facilitate adhesion between the conductor and the plastic composition.
Although the DeCoste teachings have produced samples of drop wire having adequate conductor-to-insulation adhesion values, it has been found that a conductor preheat range substantially above that disclosed in the above-mentioned ~04~
patent yields stil.l higllerl more conslstently obtalnable adhcsion valucs~ See commonly assigned copending Canadian Application Serial ~o, 207~153 filed on August 16, 1974 in tlle names ~' E. J~ George, J. L Salter, E~ S. Sauer and C. E Tidd, Jr.
Summary of thë Invention According to one aspect of the invention there is proYided a col~position of matter capable of being extruded and which includes a mixture comprising 100 parts by weight of a polyvinyl chloride homopolymer; 3 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichloro-hydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of 170 to 800; 55 to 66 parts by weight per 100 parts by weight of oolyvinyl chloride of a -. .. : -' phthalate plasticizer; 3 to 7 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 1 to 3 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent, and 5 to 35 parts by weight per 100 parts of the polyvinyl chloride of a filler constituent.
According to another aspect of the invention there is provided an elongated member having at least one conductor i covered with an extruded insulative composition of matter ' . which includes a reacted mixture comprising 100 parts by weight of polyvinyl chloride homopolymer; 3 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichloro- : -hydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of 170 to 800; 55 to 66 parts by ,., ~h~ 4 _ ~,' '. .'' ' ' . ,: "
~0'~ 7~;9 weight per .lOO parts hy weight of po].yvinyl chloride of a phthalate plasticizer; 3 to 7 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxi.de; 1 to 3 parts by weight per 100 parts by weight of the polyv;nyl chloride of a carbon black constituent; and 5 to 35 parts by weight per 100 parts of the polyvinyl chloride of a filler constituent.
According to yet another aspect of the invention 10 there is provided a method of covering a conductive member which includes the steps of advancing the conductive member v along a path and contacting the member while the member is maintained at a suitable temperature with a reaction mixture '. comprising 100 parts by we;.ght of a polyvinyl chloride homo-polymer; 3 to 10 parts by weight per 100 parts by ~eight of .I the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichlorohydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of ~ 170 to 800; 55 to 66 parts by weight per 100 parts by weight ¦ 20 of polyvinyl chloride of a phth~late plasticizer; 3 to 7 parts by weight per lOO parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 1 to 3 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; and 5 to 35 parts by , weight per 100 parts of the polyvinyl chloride of a filler constituent, to form an adherent coating on the conductive .' member comprising a reaction product of the reaction mixture.
'~ 30 1~
~ 4a _ .. ,.. ,,. _.. . .
.:
10,~3769 '`.~ "
1 ~rief Desc-i~tio~ o, .he Dr~ ings - 2 Other fe~tur_s of the present inven ion ~iill be 3 more readily understood from the follov~ing detailed
The conductors over which the plastic material is deposited are preheated within the range of 200 to 250C (392F to 482F) prior to entering the cross head die of an extruder.
In the aforementioned DeCoste patent, a PVC ~ ;
composition incorporating a brominated epoxy resin, a relatively expensive constituent, containing 18-48 percent bromine was used as the adhesive promoter. It was believed that the bromine was the functional portion of the epoxy resin that was essential to the attainment of the required adhesion. During the extrusion of the composition onto the preheated conductor, it was believed that hydrogen bromide was liberated which etched the conductor to facilitate adhesion between the conductor and the plastic composition.
Although the DeCoste teachings have produced samples of drop wire having adequate conductor-to-insulation adhesion values, it has been found that a conductor preheat range substantially above that disclosed in the above-mentioned ~04~
patent yields stil.l higllerl more conslstently obtalnable adhcsion valucs~ See commonly assigned copending Canadian Application Serial ~o, 207~153 filed on August 16, 1974 in tlle names ~' E. J~ George, J. L Salter, E~ S. Sauer and C. E Tidd, Jr.
Summary of thë Invention According to one aspect of the invention there is proYided a col~position of matter capable of being extruded and which includes a mixture comprising 100 parts by weight of a polyvinyl chloride homopolymer; 3 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichloro-hydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of 170 to 800; 55 to 66 parts by weight per 100 parts by weight of oolyvinyl chloride of a -. .. : -' phthalate plasticizer; 3 to 7 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 1 to 3 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent, and 5 to 35 parts by weight per 100 parts of the polyvinyl chloride of a filler constituent.
According to another aspect of the invention there is provided an elongated member having at least one conductor i covered with an extruded insulative composition of matter ' . which includes a reacted mixture comprising 100 parts by weight of polyvinyl chloride homopolymer; 3 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichloro- : -hydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of 170 to 800; 55 to 66 parts by ,., ~h~ 4 _ ~,' '. .'' ' ' . ,: "
~0'~ 7~;9 weight per .lOO parts hy weight of po].yvinyl chloride of a phthalate plasticizer; 3 to 7 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxi.de; 1 to 3 parts by weight per 100 parts by weight of the polyv;nyl chloride of a carbon black constituent; and 5 to 35 parts by weight per 100 parts of the polyvinyl chloride of a filler constituent.
According to yet another aspect of the invention 10 there is provided a method of covering a conductive member which includes the steps of advancing the conductive member v along a path and contacting the member while the member is maintained at a suitable temperature with a reaction mixture '. comprising 100 parts by we;.ght of a polyvinyl chloride homo-polymer; 3 to 10 parts by weight per 100 parts by ~eight of .I the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichlorohydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of ~ 170 to 800; 55 to 66 parts by weight per 100 parts by weight ¦ 20 of polyvinyl chloride of a phth~late plasticizer; 3 to 7 parts by weight per lOO parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 1 to 3 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; and 5 to 35 parts by , weight per 100 parts of the polyvinyl chloride of a filler constituent, to form an adherent coating on the conductive .' member comprising a reaction product of the reaction mixture.
'~ 30 1~
~ 4a _ .. ,.. ,,. _.. . .
.:
10,~3769 '`.~ "
1 ~rief Desc-i~tio~ o, .he Dr~ ings - 2 Other fe~tur_s of the present inven ion ~iill be 3 more readily understood from the follov~ing detailed
4 descrip.ion Oc specified em~odi~en.s thereof t-:hen read in S conjunction with the acco~panying drawings, in ~hich:
6 FIG. 1 is a cross-sectional view of a drop wire 7 l, covered with an ins~la.ing co~position in accordance with 81' the pr-nciples o~ this inven-tion;
9¦ FIG. 2 is a cross-section view of conductors 101¦ having a three layer coverir.g and representing a prior art drop wire;
12l FIG. 3 is a persepctive view sho-h~ing a typical 13! installation of the drop ~7ire from a support pole to a 1411 subscriber's premises;
lSI FIG. 4 is an enlarged view of the circled portio~
16,j of the subscri~er's premises shown in FIG. 3 and for 171i purposes of clarity illustrating the details of the provisions for supporting one e~d of the drop ~ire adjacent 1911 the subscriber's premises; and 20j~ FIG. S is a vie~ of an apparatus for applying the 21¦1 composition to the wire in accordance ~7ith the principles 221~ of this invention.
23, Detailed Description 24l A strand material in the form of a conductor 10 251 to be insulated with a composition disclosed and claimed in 2~¦ this application is an electroror~Qd copper-clad steel 271! conductive ele~ent, e.g., typically having a diameter of 2~ ! apprcximately 0.038 inch.
.' b ; 5 ~04~769 Two of the conductors 10-10 having the hereinbefore described cons-truction are covered with a composition of matter which forms an insulative covering 11. (see FIG. 1).
The insulation covering 11 is extruded simultaneously over a spaced pair of spaced conductors 10-10 to form the configu-ration shown in FIG. 1 which is commonly referred to as a drop wire, designated generally by the numeral 12.
The drop wire 12 which includes electroformed conductors 10-10 covered with the insulation 11 replaces the priorly used three layer drop wire, designated generally by the numeral 16 (see FIG. 2). As shown in FIG. 2, the conductors 10-10 were enclosed first with a rubber covering 17 followed by a textile serving layer 18 and an outer covering 19 made of neoprene.
As disclosed in the hereinbefore identified :~
Canadian application Serial No. 207,153,the plastic covered drop wire 12 may be manufactured advantageously in a single extrusion operation as compared with the prior art drop wire 16 shown in FIG. 2 manufactured in multiple steps.' Moreover, line : 20 speeds may be increased since the slower process involving the vulcanization of the neoprene and -the serving of textiles has been eliminated.
The drop wire 12 is used to bring telephone service from overhead aerial distribution cables 21-21 strung in a catenary between telephone poles 22-22 to subscriber's premises. (see FIG. 3). One end of the drop wire 12 is supported from a wedge-shaped clamp 23 attached to a pole 22 while the o-ther end is supported from a similar clamp attached to the subscriber's homes (see FIG. 4).
If there is insufficient adhesion between the inwardly facing surface of the insulation 11 and the . .
,, - ~
~049769 conductors 10-10 to transfer the weight of the drop wire 12 to the clamps 23-23, the integrity of the insulation layer may be destroyed which may result undesirably in the drop wire being supported solely by the terminal connections. It follows that the composition as applied to the conductors 10-10 must form a drop wire 12 having at least a sufficien-t minimum average adhesion of the conductors to the insulation.
There is a practical upper limit of adhesion values as well as a critical lower limit thereof because of the use to which the drop wire 12 is subjected. For example, excessive adhesion would render the drop wire extremely difficult to strip during an interconnection opera-tion. In overcoming the adhesion to remove the insulation, an installer could knick the conductors 10-10. This may affect adversely the electrical properties of -the conductors 10-10 as well as penetrate the copper cladding thereby exposing the steel core to possible corrosion.
Lastly, the composition as applied to the conductors 10-10 must have requisite physical, electrical and service life properties and must not degrade during the processing thereof, The basic polymer which is utili~ed in the inven-tive composition is a polyvinyl chloride (PVC) resin, a homopolymer. The PVC resin has all of the characteris-tics associated with a homopolymer including abrasion resistance, but which, however, includes thermal instability which creates processing problems. However, when the PVC resin is caused to soften during process;ng made possible by the ; addition of additives to the compound, the .~ '.
resistance to abrasion is reduced. Fur-ther, the PVC must be a suitable electrical grade PVC homopolymer.
The PVC resin may be any of a number of PVC resins well known in the art for use as electrical insulation. In accordance with the A.S.T.M. standard for 1966, suitable homopolymers may be classified as within the range of from GP5~0003 to GP6~0003, inclusive. Definition of these characteristics are set forth in the A.S.T.M. standard under designation D1755-66.
Briefly, the designation, GP, designates a general purpose resin primarily intended for calendaring, extrusion or molding processes. The first numerals (entries 5 through 6) represent a polymer molecular weight in terms of dilute soluton viscosity and the last digit, 3, indicates the usual preference for an electrical conductivity less than 6 micro-mhos per centimeter per gram. This electrical characteristic is, of course, not a basic requirement form the standpoint of the inventive teaching. The bar under or the bar over a numeral indicates a value less than or more than, respectively, the cell classification for that numeral. The four ciphers in the designations indicate that the properties of particle size, apparent bulk density, plasticizer absorption and dry flow are at the descretion of the customer in that any A.S.T.M. cell classification may be used.
It is convenient to discuss concentrations in terms of parts by weight based on 100 parts of the polymeric material. The term polymeric material is defind as consist-ing essentially of the PVC homopolymer. Concentrations so designated, therefore, result in compositions having greater -than 100 parts.
.
-: .
~049769 Combined with the PVC to facilitate processing, including the extrusion, of the composition is a monomeric plasticizer. The selected monomeric plasticizer must be an acceptable low temperature plasticizer. An acceptable low temperature plasticizer is one which combines with the PVC
resin during compounding to become inserted between the molecules of the resin. In this way, at low temperatures of say 0F and below, the low temperature plasticizer acts as bearings or rollers between the PVC resin molecules to maintain the material in a flexible condition.
Ano-ther problem arises in attempting to optimize the range of the monomeric plasticizer which is used. The plasticizers employed typically are members of the ester family which includes esters having a straight chain or a branch chain. The straight chain ester materials are generally more effective in maintaining flexibility at low temperatures than branch chain materials, i.e~, esters having at least 35 percent branch chains.
There are many commercially available monomeric plasticizers, but the low temperature flexibility, electri-cal properties and volatility of the plasticizers vary.
The monomeric plas-ticizer must cooperate with the other constituents of the composition to provide the overall requirements and service life of the drop wire. A suitable plasticizer is one having suitable low temperature flexi-bility and electrical properties. A preferred plasticizer includes a phthalate plasticizer.
; A preferred concentration of the monomeric plasti-cizer added to the PVC is 55-66 parts by weight of the phtha-late plasticizer to 100 parts by weight of the PVC. Less than 55 parts compromises low temperature flexing properties;
more than 66 parts reduces the flame retardancy and _g _ -~049769 also results in a composition having poor elec-trical properties and less than desireable compression resistance.
This could cause a possible movement of the end of the drop wire 12 wi-thin the clamp 23.
Typical suitable phthalate plasticizers employed in the inventive composition include, for example, mixed normal alkyl phthalate such as N-octyl-n-decyl phthalate (designated 810P), N-hexyl-n-octyl-n-decyl phthalate (designated 610P), or a branch chain phthalate trademark product of the Monsanto Company designated "Santi-cizer" 711 or a blend of these monomeric plasticizers.
It has been found that NODP, as marketed by the U. S. Steel Chemical Company under the designation PX-318 LTrade Mark~
is a suitable phthalate plasticizer.
Added to the polyvinyl chloride base and -the phthalate plasticizer is a non-brominated unmodified liquid epoxy resin based on the condensation of epichlorohydrin and Bisphenol A. The epoxy resin is an important constituent in the composition in that it is the primary vehicle for ob-taining the adhesion of the insula-tion to the conductors 10-10. The epoxy resins are of the type as prepared and characterized in accordance with ASTM D-1763, Type I, Grade I regarding pure unmodified epoxies formulated from epichlorohydrin and Bisphenol.
One of the characteristics of epoxy resin which may be used as an indication of structure and usefulness is ; that of weight per epoxy equivalen-t (commonly referred to as WPE) or weight per epoxide. The weight per epoxy equivalent is the total molecular weight divided by the total number of epoxide groups. ASTM D1652 describes methods of .
- :
measuring the weight per epoxy equivalent. The higher the weight per epoxy equivalent, the larger the epoxy resin molecules. Also, as the weight per epoxy equivalent in-creases, the softening point increases. Of course, as the softening point increases, the more difficult is the process of incorporating the epoxy resin into the composition and -after approximately 90C becomes undesirable.
The above-mentioned ASTM, Type I, Grade I epoxy resin is further broken down into four classes. Class I
includes liquid epoxy resins having a weight per epoxy equiva-lent of 170-200. Class II is a more viscous liquid while Class III includes semi-solids. Class IV include solids having a weight per epoxy equivalent of 280-800 with a Durrans' Softening Point of 40 to 90C.
It has been found that non-brominated epoxy resin desirably is present in an amount of 3 to 10 parts by weight per 100 parts by weight of the PVC. If less than three parts ~ of the epoxy resin is used, the adhesion between the plastic ; composition and the conductors is reduced. On the other hand, no improvement in adhesion is achieved if more han ten parts by weight of the epoxy resin would be used.
A suitable non-brominated unmodified epoxy resin is ~ -a trademark product marketed by the Shell Chemical Company under the designation "EPON" 828*. This constituent is an uncured epoxy (liquid) having an epoxide equivalent of 175-; 210 and an average molecular weight of 350-400.
It will be recalled that the drop wire insulated with this composition is strung up to the subscriber's premises. An antimony trioxide constituent must be used in ; *Trademark -11-:`' , ~049769 order to render the inventive composition flame retardant.
It is desirable for drop wire manufactured in accordance with certain requirements deemed necessary for subscriber installation that a minimum limiting oxygen index of twenty-six percent, as determined in accordance with A.S.T.M. D-2863, be achieved. The antimony trioxide is an essential part of the inventive composition in achieving the minimum limiting oxygen index of twenty-six percent.
A preferred concentration of the antimony trioxide added to the PVC is 3 to 5 parts by weight of the antimony trioxide to 100 parts by weight of the PVC.
A delicate balancing of the number of parts by weight of the antimony trioxide in relation to the other ; constituents of the composition ;s necessary. If less than three parts are employed, the limiting oxygen index require- -ment is not met. On the other hand, the greater the number of parts by weight of the antimony trioxide, the higher the limiting oxygen index. However, the use of more than five parts of antimony trioxide does not provide any subs-tantial improvement in achieving additional flame retardancy. This material also acts as a filler.
The antimony trioxide may be of several marketed commercially. One antimony trioxide suitable for purposes of this composition is marketed by N.L Industries under the designation Regular Grade antimony trioxide.
Added to the PVC, the phthalate plasticizer, the epoxy resin and the antimony trioxide is metallic stabilizer.
The metallic stabilizer is added to the PVC to protect the , -12-.
~' ' ' resultant composition against thermal degrada-tion during the extrusion process and to improve the electrical resistivity of the composition.
A preferred concentration of the metallic stabilizer is three to seven parts by weight per 100 parts by weight of the PVC. If less than three parts are used, thermal heat stability is sacrificed which could result in processing difficulties. Moreover, the electrical properties of the insulation would be poor. While more than seven parts could be used, no improvement in electrical properties nor heat stability is realized.
The metallic stabilizer may be present in solid form or dispersed in a carrier such as the phthalate plasticizer. It has been found that a liquid metallic stabilizer may be added to the compounding mixture together with the other liquid constituents to benefit the composition -at an early stage of preparation.
A suitable me-tallic stabilizer marketed by N L
Industries, Inc. as "Tribase" E-XL has been found satisfac-tory for purposes of the composition. Tribase E-XL is a trademark product including a ~asic lead silicate sulfate and having a specific gravity of 4.0 and a lead oxide content of 64.3%.
~ Added to the PVC, the phthalate plasticizer, the ; metallic stabilizer, the epoxy resin and the antimony trioxide is a filler material. This material is generally in powder form and is of assistance in promoting the adhesion of the composition to the conductors 10-10.
A preferred concentration of the filler material is 5 to 35 parts by weight per 100 parts by weight of the ~ ~49~69 PVC. If less than five parts are used, the electrical properties are compromised since the composition would result in a higher percent of plasticizers. If more than thirty-five parts are used, impact resistance and low temperature flexibility are sacrificed.
A trademark product, "Cab-O-Sil", is marketed by the Cabot Corporation has been found to be acceptable for purposes of the composition. Calcined clay and calcium carbonate are also suitable filler constituents and several combinations and/or subcombinations of these constituents ; suffice as a filler subsystem to the claimed composition.
In order to provide adequate light stability for the inventive composition, ~n ultraviolet absorber is combined with the PVC, the plasticizers and the metallic stabilizer. The addition of the ultraviolet absorber is of assistance in avoïding ultraviolet degradation of the drop wire having the inventive composition covering the conductors. This may occur, for example, when an unprote~ted PVC is exposed to sunlight.
A preferred concentration added to the PVC is 1.0 to 3.0 parts by weight of the ultraviolet absorber per 100 parts by weight of the PVC homopolymer. If less than 1.0 part is used, the protection against ultraviolet exposure and the environment is reduced thereby shortening the service life of the wire. However, more than 3.0 parts are un- `
neoessary since adequate protection is achieved by an amount falling within the stated range. The ultraviolet absorber must be uniformly dispersed throughout the composition to provide the desired weather resistance.
One family of ultraviolet absorbers which is a~ailable and has been found to be acceptable are the ' ~ ~
_.. . ..
carbon black family as marke-ted as a trademark product by the Cities Service Company and designa-ted "Superba" 999. The "Superba" 999 is a medium color channel type black with an ash content of 0.05% by weight with a volatile matter maximum content of 10% ~d a primary particle size of 20 millimicrons.
This material also acts as a filler and functions to promote the adhesion of the insulation to the conductors lO-lO.
The hereinbefore described composition has been -found to satisfy the requirements of a drop wire insulation.
Heat stability studies supported by actual extrusion trials demonstrate that the inventive composition provides excellent adhesion to the conductors as well as long term heat stability. Specifically, the composition (1) is flame retardant (2) is weather resistant (3) is extrudable and (4) has excellent low temperature impact resistance properties.
Although the covering of conductors lO-lO with the composition disclosed in the J. B. DeCoste patent 3,579,608 by using the process disclosed in the above identified E.J.Georgeet~l.
Application Serial No. 207,153 produces acceptable product, the use of the reaction mixture herein disclosed including a non-brominated epoxy resin results in substantial cost savings as well as yielding reproducible average conductor-to-insulation adhesion values in the desired range.
It is to be noted that a preferred composition which gives optimum adhesion values comprises lO0 parts by weight oE a polyvinyl chloride (PVC), 7 parts by weight per 100 parts by weight of the PVC of a non-brominated epoxy resin having a weight per ap~,xy equivalen-t of approximately l90, 66 parts by weight per lO0 parts by weight of the PVC of a phthalate plasticizer, 5 parts by weight over 100 parts by ' 10'~9'7~g weight of the PVC of a metallic stabilizer, 3 parts by weight per 100 parts by weight of the PVC of antimony trioxide, 2.5 parts by weight per 100 parts by weight of the PVC of a carbon black constituent, 5 parts by weight per 100 parts by weight of the PVC o~ fumed silica and 5 parts by weight per 100 parts by weight of the PVC of calcined elay.
Methods of Preparing and Applying the Composition .
The principles of the methods of this invention are used to apply an insulation to strand material such as the copper-steel conductors 10-10 such that there is an optimum adhesion between the conductors and the composition.
It has been found that an adhesion of the composition to eaeh conductor in the neighborhood of approximately 15-25 pounds is preferred with limits of 8-32 pounds being permitted providing the average adhesion of the two conductors is a minimum of 12 pounds.
The use of eonduetor preheat temperatures as taught in the above-identified George et al. Application Serial No. 207,153 results in an insulated conductor having the desired permanent adhesion characteristics of insulation to metal. This oeeurred as a result of preheat-; ing the conductor in the range of 525 to 675F and then extruding thereover a eomposition such as that diselosed and elaimed in DeCoste patent 3,579,603. It has also been ; found that the composition of this invention may also be extruded thereover to provide a drop wire 12 having equally exeellent properties including adhesion.
~, '- ' ' - ' .: . .- .:, : ~
In practicing -the method embodying the principles of this invention, a pair of copper covered steel conductors 10-10 destined to be enclosed with the reactive mixture are advanced along a manufacturing line, designated generally by the number 31 (see FIG. 5) in spaced generally parallel relationship. The composition is applied to the conductors 10-10 as they are advanced through a dual channel core tube (not shown) of an extruder 32.
Prior to the entry of the wires 10-10 into the lQ extruder 32, the wires are preheated to a temperature in the range of 450F to 650F and preferably in a range of 575F
to 625F. The preheating of the wires 10-10 may be accomplished by any number of conventional preheating facilities, des;gnated generally by the numeral 33, includ-ing inductive-resistance heating. In order to prevent excessive heating of the conductors 10-10 and to minimize convective and radiation heat losses, the conductors are advanced through an insulated chamber 34 interposed between the preheating facilities 33 and the extruder 32.
In the process of preparing -the composition for application to the wires 10-10 in accordance with the principles of this invention, the PVC admixed with a non-brominated unmodified epoxy resin and other compounding ingredients heretofore disclosed are fed into and through the extruder 32. The details of the extruder 32 are well known in the ar-t and are described in the aforementioned ; George et al. Application Serial No. 207,153.
The material flows toward a die 36 and ultimately toward engagement with the conductors 10-10 pàssing through the die. It will be recalled that a definite preheat has been imparted to the conductors 10-10 which are moved ~049769 continuously through the crosshead die 36. In this way, the composition is extruded over the preheated conductors which are moved continuously through the die 36 and which act as internal forming mandrels.
Previously, the epoxy resin was identified as the constituent primarily relied on to ob-tain the requisite average adhesion of the insulation to the conductors 10-10.
However, when using epoxies, it is customary to use a two part system, a resin and a hardener, which are mixed together at the point of use, with the hardener curing the resin.
Reproducible acceptable average adhesion values are obtained by practicing the principles of this inven-tion suprisingly without the use of a hardener.
The engagement of the composition with conductors 10-10 preheated to within the specified range causes a reaction to occur within the mixture which unexpectedly cures the epoxy resin and promotes adhesion between the reaction product ;
and the wire. The preheated conductors 10-10 cause the poly-vinyl chloride to degrade at the interface of the copper-clad steel conductors and the covering composi-tion. Hydrochloric acid is liberated as one of the byproducts of the degradation of the PVC. The hydrochloric acid is believed to etch the surfaces of the conductor 10-10 and acts as a catalytic curing agent for the epoxy resin giving an instantbond at the interface of the conductors and the composition to yield consistently acceptable adhesion values.
The presence of a lubricant may interfere with the adhesion of the composition to the conductors 10-10.
Although a lubricant constituent in and of itself is not an element of the composition, the metallic stabilizer which is used may be surface coated wi-th a lubricant.
`:
However, at the temperatures specified in practicing this invention 9 the degradation of the PVC is such that sufficient hydrochloric acid is produced to react and cure the epoxy resin thereby minimizing the effect of any lubricant which may be present.
It has been found that notwithstanding the use of a stabilizer which does not include a lubricant that temperature ranges below those specified will not result in consistently reproducible adhesion values of the composition to the conductors 10-10. While the use of the upper limit of the temperature range ~392 to 482F) stated in the above-identified DeCoste patent has resulted in adhesion values of the composition which border in the range of 8-12 pounds, the results may be improved and rendered reproducible for in-line production control.
In order to achieve a reproducible average conductor-to-composition-adhesion of at least 12 pounds, temperatures in the preferred range of 575 to 625F are used.
It has been found that generally acceptable 20 average composition to conductor adhesion values have been obtained when using conduc-tor preheat temperatures in the range of 450 to 650F. The lower end of this range is somewhat less than that disclosed in the hereinbefore identified Application Serial No. 207,153 in which the composition included 3 to 10 and preferably 7 parts by weight, per 100 parts by weight of PVC, of a brominated epoxy resin.
Since that constituent included 48% bromine, less epoxide radials were present. With the non-brominated epoxy resin more epoxy groups are present for the same number of parts.
Hence, lower preheat temperatures could be used when compounding the same number of parts of the epoxy resin or less parts could be used with a higher preheat range.
Tests have shown that the adhesion varies with respect to the conductor preheat temperature. There is a critical lower limit below which the adhesion begins a generally rapid decline with non-reproducible results. As an example, insulation extruded over conductors 10-10 preheated to generally below 450F was found to be capable of being pulled manually from the conductors.
There is also an upper limit~of temperature beyond which` the adhesion values are affected adversely by the thermal degradation of the insulation. It has also been found that after a conductor preheat temperature of approximately 650 F, the adhesion of the insulation to the conductor decreases. Apparently, conductor preheat tempera-tures in excess of 650F causes the bonding process herein-before described to become less effective. If the epoxy resin constituent is subjected to this excessive heat upon engaging the conductor 10, the bond between the conductor and the insulation can become~degraded.
In order to test the adhesion of the composition to the conductors 10-10, the plastic covered drop wire 12 is subjected to what is referred to as a slip-bff test.
This test is described in detail in the hereinbefore-referred-to Application Serial No. 207,153. This test measures in pounds the force applied parallel to the axis of the conductors 10-10 and which is required to pull a 3/8 inch length of insulation from one end of the conductor. The applied force at which the insulation is pulled off the ~ -conductor is recorded and is determined to be the magnitude of adhesion of the composition to the conductor.
'.
;
1049'769 The drop wire 12 is also subjected to a compression test, an elongation test, low temperature flexibility, clamp holding and impact tests, all of which are described in the aforementioned Application Serial No. 207,153.
The following examples illustrate various flexible PVC insulation compositions prepared in accordance with the invention. The examples are summarized in Table I and are set forth in tabular form. For comparison purposes, all examples set forth were carried out using the homopolymer described hereinbefore. ~oreover, all amounts are in parts by weight.
TABLE I
Exam~les Ranges Constituent A B C D
100 PVC Resin 100 100 100 100 3-10 Epoxy Resin 7 7 10 4 55-66 Phthalate Plasticizers66 60 55 66 3-7 Metallic Stabilizer 5 3 7 5 3-5 Antimony Trioxide 3 5 4 3 1-3 Carbon Elack 2.5 3 1 2.5
6 FIG. 1 is a cross-sectional view of a drop wire 7 l, covered with an ins~la.ing co~position in accordance with 81' the pr-nciples o~ this inven-tion;
9¦ FIG. 2 is a cross-section view of conductors 101¦ having a three layer coverir.g and representing a prior art drop wire;
12l FIG. 3 is a persepctive view sho-h~ing a typical 13! installation of the drop ~7ire from a support pole to a 1411 subscriber's premises;
lSI FIG. 4 is an enlarged view of the circled portio~
16,j of the subscri~er's premises shown in FIG. 3 and for 171i purposes of clarity illustrating the details of the provisions for supporting one e~d of the drop ~ire adjacent 1911 the subscriber's premises; and 20j~ FIG. S is a vie~ of an apparatus for applying the 21¦1 composition to the wire in accordance ~7ith the principles 221~ of this invention.
23, Detailed Description 24l A strand material in the form of a conductor 10 251 to be insulated with a composition disclosed and claimed in 2~¦ this application is an electroror~Qd copper-clad steel 271! conductive ele~ent, e.g., typically having a diameter of 2~ ! apprcximately 0.038 inch.
.' b ; 5 ~04~769 Two of the conductors 10-10 having the hereinbefore described cons-truction are covered with a composition of matter which forms an insulative covering 11. (see FIG. 1).
The insulation covering 11 is extruded simultaneously over a spaced pair of spaced conductors 10-10 to form the configu-ration shown in FIG. 1 which is commonly referred to as a drop wire, designated generally by the numeral 12.
The drop wire 12 which includes electroformed conductors 10-10 covered with the insulation 11 replaces the priorly used three layer drop wire, designated generally by the numeral 16 (see FIG. 2). As shown in FIG. 2, the conductors 10-10 were enclosed first with a rubber covering 17 followed by a textile serving layer 18 and an outer covering 19 made of neoprene.
As disclosed in the hereinbefore identified :~
Canadian application Serial No. 207,153,the plastic covered drop wire 12 may be manufactured advantageously in a single extrusion operation as compared with the prior art drop wire 16 shown in FIG. 2 manufactured in multiple steps.' Moreover, line : 20 speeds may be increased since the slower process involving the vulcanization of the neoprene and -the serving of textiles has been eliminated.
The drop wire 12 is used to bring telephone service from overhead aerial distribution cables 21-21 strung in a catenary between telephone poles 22-22 to subscriber's premises. (see FIG. 3). One end of the drop wire 12 is supported from a wedge-shaped clamp 23 attached to a pole 22 while the o-ther end is supported from a similar clamp attached to the subscriber's homes (see FIG. 4).
If there is insufficient adhesion between the inwardly facing surface of the insulation 11 and the . .
,, - ~
~049769 conductors 10-10 to transfer the weight of the drop wire 12 to the clamps 23-23, the integrity of the insulation layer may be destroyed which may result undesirably in the drop wire being supported solely by the terminal connections. It follows that the composition as applied to the conductors 10-10 must form a drop wire 12 having at least a sufficien-t minimum average adhesion of the conductors to the insulation.
There is a practical upper limit of adhesion values as well as a critical lower limit thereof because of the use to which the drop wire 12 is subjected. For example, excessive adhesion would render the drop wire extremely difficult to strip during an interconnection opera-tion. In overcoming the adhesion to remove the insulation, an installer could knick the conductors 10-10. This may affect adversely the electrical properties of -the conductors 10-10 as well as penetrate the copper cladding thereby exposing the steel core to possible corrosion.
Lastly, the composition as applied to the conductors 10-10 must have requisite physical, electrical and service life properties and must not degrade during the processing thereof, The basic polymer which is utili~ed in the inven-tive composition is a polyvinyl chloride (PVC) resin, a homopolymer. The PVC resin has all of the characteris-tics associated with a homopolymer including abrasion resistance, but which, however, includes thermal instability which creates processing problems. However, when the PVC resin is caused to soften during process;ng made possible by the ; addition of additives to the compound, the .~ '.
resistance to abrasion is reduced. Fur-ther, the PVC must be a suitable electrical grade PVC homopolymer.
The PVC resin may be any of a number of PVC resins well known in the art for use as electrical insulation. In accordance with the A.S.T.M. standard for 1966, suitable homopolymers may be classified as within the range of from GP5~0003 to GP6~0003, inclusive. Definition of these characteristics are set forth in the A.S.T.M. standard under designation D1755-66.
Briefly, the designation, GP, designates a general purpose resin primarily intended for calendaring, extrusion or molding processes. The first numerals (entries 5 through 6) represent a polymer molecular weight in terms of dilute soluton viscosity and the last digit, 3, indicates the usual preference for an electrical conductivity less than 6 micro-mhos per centimeter per gram. This electrical characteristic is, of course, not a basic requirement form the standpoint of the inventive teaching. The bar under or the bar over a numeral indicates a value less than or more than, respectively, the cell classification for that numeral. The four ciphers in the designations indicate that the properties of particle size, apparent bulk density, plasticizer absorption and dry flow are at the descretion of the customer in that any A.S.T.M. cell classification may be used.
It is convenient to discuss concentrations in terms of parts by weight based on 100 parts of the polymeric material. The term polymeric material is defind as consist-ing essentially of the PVC homopolymer. Concentrations so designated, therefore, result in compositions having greater -than 100 parts.
.
-: .
~049769 Combined with the PVC to facilitate processing, including the extrusion, of the composition is a monomeric plasticizer. The selected monomeric plasticizer must be an acceptable low temperature plasticizer. An acceptable low temperature plasticizer is one which combines with the PVC
resin during compounding to become inserted between the molecules of the resin. In this way, at low temperatures of say 0F and below, the low temperature plasticizer acts as bearings or rollers between the PVC resin molecules to maintain the material in a flexible condition.
Ano-ther problem arises in attempting to optimize the range of the monomeric plasticizer which is used. The plasticizers employed typically are members of the ester family which includes esters having a straight chain or a branch chain. The straight chain ester materials are generally more effective in maintaining flexibility at low temperatures than branch chain materials, i.e~, esters having at least 35 percent branch chains.
There are many commercially available monomeric plasticizers, but the low temperature flexibility, electri-cal properties and volatility of the plasticizers vary.
The monomeric plas-ticizer must cooperate with the other constituents of the composition to provide the overall requirements and service life of the drop wire. A suitable plasticizer is one having suitable low temperature flexi-bility and electrical properties. A preferred plasticizer includes a phthalate plasticizer.
; A preferred concentration of the monomeric plasti-cizer added to the PVC is 55-66 parts by weight of the phtha-late plasticizer to 100 parts by weight of the PVC. Less than 55 parts compromises low temperature flexing properties;
more than 66 parts reduces the flame retardancy and _g _ -~049769 also results in a composition having poor elec-trical properties and less than desireable compression resistance.
This could cause a possible movement of the end of the drop wire 12 wi-thin the clamp 23.
Typical suitable phthalate plasticizers employed in the inventive composition include, for example, mixed normal alkyl phthalate such as N-octyl-n-decyl phthalate (designated 810P), N-hexyl-n-octyl-n-decyl phthalate (designated 610P), or a branch chain phthalate trademark product of the Monsanto Company designated "Santi-cizer" 711 or a blend of these monomeric plasticizers.
It has been found that NODP, as marketed by the U. S. Steel Chemical Company under the designation PX-318 LTrade Mark~
is a suitable phthalate plasticizer.
Added to the polyvinyl chloride base and -the phthalate plasticizer is a non-brominated unmodified liquid epoxy resin based on the condensation of epichlorohydrin and Bisphenol A. The epoxy resin is an important constituent in the composition in that it is the primary vehicle for ob-taining the adhesion of the insula-tion to the conductors 10-10. The epoxy resins are of the type as prepared and characterized in accordance with ASTM D-1763, Type I, Grade I regarding pure unmodified epoxies formulated from epichlorohydrin and Bisphenol.
One of the characteristics of epoxy resin which may be used as an indication of structure and usefulness is ; that of weight per epoxy equivalen-t (commonly referred to as WPE) or weight per epoxide. The weight per epoxy equivalent is the total molecular weight divided by the total number of epoxide groups. ASTM D1652 describes methods of .
- :
measuring the weight per epoxy equivalent. The higher the weight per epoxy equivalent, the larger the epoxy resin molecules. Also, as the weight per epoxy equivalent in-creases, the softening point increases. Of course, as the softening point increases, the more difficult is the process of incorporating the epoxy resin into the composition and -after approximately 90C becomes undesirable.
The above-mentioned ASTM, Type I, Grade I epoxy resin is further broken down into four classes. Class I
includes liquid epoxy resins having a weight per epoxy equiva-lent of 170-200. Class II is a more viscous liquid while Class III includes semi-solids. Class IV include solids having a weight per epoxy equivalent of 280-800 with a Durrans' Softening Point of 40 to 90C.
It has been found that non-brominated epoxy resin desirably is present in an amount of 3 to 10 parts by weight per 100 parts by weight of the PVC. If less than three parts ~ of the epoxy resin is used, the adhesion between the plastic ; composition and the conductors is reduced. On the other hand, no improvement in adhesion is achieved if more han ten parts by weight of the epoxy resin would be used.
A suitable non-brominated unmodified epoxy resin is ~ -a trademark product marketed by the Shell Chemical Company under the designation "EPON" 828*. This constituent is an uncured epoxy (liquid) having an epoxide equivalent of 175-; 210 and an average molecular weight of 350-400.
It will be recalled that the drop wire insulated with this composition is strung up to the subscriber's premises. An antimony trioxide constituent must be used in ; *Trademark -11-:`' , ~049769 order to render the inventive composition flame retardant.
It is desirable for drop wire manufactured in accordance with certain requirements deemed necessary for subscriber installation that a minimum limiting oxygen index of twenty-six percent, as determined in accordance with A.S.T.M. D-2863, be achieved. The antimony trioxide is an essential part of the inventive composition in achieving the minimum limiting oxygen index of twenty-six percent.
A preferred concentration of the antimony trioxide added to the PVC is 3 to 5 parts by weight of the antimony trioxide to 100 parts by weight of the PVC.
A delicate balancing of the number of parts by weight of the antimony trioxide in relation to the other ; constituents of the composition ;s necessary. If less than three parts are employed, the limiting oxygen index require- -ment is not met. On the other hand, the greater the number of parts by weight of the antimony trioxide, the higher the limiting oxygen index. However, the use of more than five parts of antimony trioxide does not provide any subs-tantial improvement in achieving additional flame retardancy. This material also acts as a filler.
The antimony trioxide may be of several marketed commercially. One antimony trioxide suitable for purposes of this composition is marketed by N.L Industries under the designation Regular Grade antimony trioxide.
Added to the PVC, the phthalate plasticizer, the epoxy resin and the antimony trioxide is metallic stabilizer.
The metallic stabilizer is added to the PVC to protect the , -12-.
~' ' ' resultant composition against thermal degrada-tion during the extrusion process and to improve the electrical resistivity of the composition.
A preferred concentration of the metallic stabilizer is three to seven parts by weight per 100 parts by weight of the PVC. If less than three parts are used, thermal heat stability is sacrificed which could result in processing difficulties. Moreover, the electrical properties of the insulation would be poor. While more than seven parts could be used, no improvement in electrical properties nor heat stability is realized.
The metallic stabilizer may be present in solid form or dispersed in a carrier such as the phthalate plasticizer. It has been found that a liquid metallic stabilizer may be added to the compounding mixture together with the other liquid constituents to benefit the composition -at an early stage of preparation.
A suitable me-tallic stabilizer marketed by N L
Industries, Inc. as "Tribase" E-XL has been found satisfac-tory for purposes of the composition. Tribase E-XL is a trademark product including a ~asic lead silicate sulfate and having a specific gravity of 4.0 and a lead oxide content of 64.3%.
~ Added to the PVC, the phthalate plasticizer, the ; metallic stabilizer, the epoxy resin and the antimony trioxide is a filler material. This material is generally in powder form and is of assistance in promoting the adhesion of the composition to the conductors 10-10.
A preferred concentration of the filler material is 5 to 35 parts by weight per 100 parts by weight of the ~ ~49~69 PVC. If less than five parts are used, the electrical properties are compromised since the composition would result in a higher percent of plasticizers. If more than thirty-five parts are used, impact resistance and low temperature flexibility are sacrificed.
A trademark product, "Cab-O-Sil", is marketed by the Cabot Corporation has been found to be acceptable for purposes of the composition. Calcined clay and calcium carbonate are also suitable filler constituents and several combinations and/or subcombinations of these constituents ; suffice as a filler subsystem to the claimed composition.
In order to provide adequate light stability for the inventive composition, ~n ultraviolet absorber is combined with the PVC, the plasticizers and the metallic stabilizer. The addition of the ultraviolet absorber is of assistance in avoïding ultraviolet degradation of the drop wire having the inventive composition covering the conductors. This may occur, for example, when an unprote~ted PVC is exposed to sunlight.
A preferred concentration added to the PVC is 1.0 to 3.0 parts by weight of the ultraviolet absorber per 100 parts by weight of the PVC homopolymer. If less than 1.0 part is used, the protection against ultraviolet exposure and the environment is reduced thereby shortening the service life of the wire. However, more than 3.0 parts are un- `
neoessary since adequate protection is achieved by an amount falling within the stated range. The ultraviolet absorber must be uniformly dispersed throughout the composition to provide the desired weather resistance.
One family of ultraviolet absorbers which is a~ailable and has been found to be acceptable are the ' ~ ~
_.. . ..
carbon black family as marke-ted as a trademark product by the Cities Service Company and designa-ted "Superba" 999. The "Superba" 999 is a medium color channel type black with an ash content of 0.05% by weight with a volatile matter maximum content of 10% ~d a primary particle size of 20 millimicrons.
This material also acts as a filler and functions to promote the adhesion of the insulation to the conductors lO-lO.
The hereinbefore described composition has been -found to satisfy the requirements of a drop wire insulation.
Heat stability studies supported by actual extrusion trials demonstrate that the inventive composition provides excellent adhesion to the conductors as well as long term heat stability. Specifically, the composition (1) is flame retardant (2) is weather resistant (3) is extrudable and (4) has excellent low temperature impact resistance properties.
Although the covering of conductors lO-lO with the composition disclosed in the J. B. DeCoste patent 3,579,608 by using the process disclosed in the above identified E.J.Georgeet~l.
Application Serial No. 207,153 produces acceptable product, the use of the reaction mixture herein disclosed including a non-brominated epoxy resin results in substantial cost savings as well as yielding reproducible average conductor-to-insulation adhesion values in the desired range.
It is to be noted that a preferred composition which gives optimum adhesion values comprises lO0 parts by weight oE a polyvinyl chloride (PVC), 7 parts by weight per 100 parts by weight of the PVC of a non-brominated epoxy resin having a weight per ap~,xy equivalen-t of approximately l90, 66 parts by weight per lO0 parts by weight of the PVC of a phthalate plasticizer, 5 parts by weight over 100 parts by ' 10'~9'7~g weight of the PVC of a metallic stabilizer, 3 parts by weight per 100 parts by weight of the PVC of antimony trioxide, 2.5 parts by weight per 100 parts by weight of the PVC of a carbon black constituent, 5 parts by weight per 100 parts by weight of the PVC o~ fumed silica and 5 parts by weight per 100 parts by weight of the PVC of calcined elay.
Methods of Preparing and Applying the Composition .
The principles of the methods of this invention are used to apply an insulation to strand material such as the copper-steel conductors 10-10 such that there is an optimum adhesion between the conductors and the composition.
It has been found that an adhesion of the composition to eaeh conductor in the neighborhood of approximately 15-25 pounds is preferred with limits of 8-32 pounds being permitted providing the average adhesion of the two conductors is a minimum of 12 pounds.
The use of eonduetor preheat temperatures as taught in the above-identified George et al. Application Serial No. 207,153 results in an insulated conductor having the desired permanent adhesion characteristics of insulation to metal. This oeeurred as a result of preheat-; ing the conductor in the range of 525 to 675F and then extruding thereover a eomposition such as that diselosed and elaimed in DeCoste patent 3,579,603. It has also been ; found that the composition of this invention may also be extruded thereover to provide a drop wire 12 having equally exeellent properties including adhesion.
~, '- ' ' - ' .: . .- .:, : ~
In practicing -the method embodying the principles of this invention, a pair of copper covered steel conductors 10-10 destined to be enclosed with the reactive mixture are advanced along a manufacturing line, designated generally by the number 31 (see FIG. 5) in spaced generally parallel relationship. The composition is applied to the conductors 10-10 as they are advanced through a dual channel core tube (not shown) of an extruder 32.
Prior to the entry of the wires 10-10 into the lQ extruder 32, the wires are preheated to a temperature in the range of 450F to 650F and preferably in a range of 575F
to 625F. The preheating of the wires 10-10 may be accomplished by any number of conventional preheating facilities, des;gnated generally by the numeral 33, includ-ing inductive-resistance heating. In order to prevent excessive heating of the conductors 10-10 and to minimize convective and radiation heat losses, the conductors are advanced through an insulated chamber 34 interposed between the preheating facilities 33 and the extruder 32.
In the process of preparing -the composition for application to the wires 10-10 in accordance with the principles of this invention, the PVC admixed with a non-brominated unmodified epoxy resin and other compounding ingredients heretofore disclosed are fed into and through the extruder 32. The details of the extruder 32 are well known in the ar-t and are described in the aforementioned ; George et al. Application Serial No. 207,153.
The material flows toward a die 36 and ultimately toward engagement with the conductors 10-10 pàssing through the die. It will be recalled that a definite preheat has been imparted to the conductors 10-10 which are moved ~049769 continuously through the crosshead die 36. In this way, the composition is extruded over the preheated conductors which are moved continuously through the die 36 and which act as internal forming mandrels.
Previously, the epoxy resin was identified as the constituent primarily relied on to ob-tain the requisite average adhesion of the insulation to the conductors 10-10.
However, when using epoxies, it is customary to use a two part system, a resin and a hardener, which are mixed together at the point of use, with the hardener curing the resin.
Reproducible acceptable average adhesion values are obtained by practicing the principles of this inven-tion suprisingly without the use of a hardener.
The engagement of the composition with conductors 10-10 preheated to within the specified range causes a reaction to occur within the mixture which unexpectedly cures the epoxy resin and promotes adhesion between the reaction product ;
and the wire. The preheated conductors 10-10 cause the poly-vinyl chloride to degrade at the interface of the copper-clad steel conductors and the covering composi-tion. Hydrochloric acid is liberated as one of the byproducts of the degradation of the PVC. The hydrochloric acid is believed to etch the surfaces of the conductor 10-10 and acts as a catalytic curing agent for the epoxy resin giving an instantbond at the interface of the conductors and the composition to yield consistently acceptable adhesion values.
The presence of a lubricant may interfere with the adhesion of the composition to the conductors 10-10.
Although a lubricant constituent in and of itself is not an element of the composition, the metallic stabilizer which is used may be surface coated wi-th a lubricant.
`:
However, at the temperatures specified in practicing this invention 9 the degradation of the PVC is such that sufficient hydrochloric acid is produced to react and cure the epoxy resin thereby minimizing the effect of any lubricant which may be present.
It has been found that notwithstanding the use of a stabilizer which does not include a lubricant that temperature ranges below those specified will not result in consistently reproducible adhesion values of the composition to the conductors 10-10. While the use of the upper limit of the temperature range ~392 to 482F) stated in the above-identified DeCoste patent has resulted in adhesion values of the composition which border in the range of 8-12 pounds, the results may be improved and rendered reproducible for in-line production control.
In order to achieve a reproducible average conductor-to-composition-adhesion of at least 12 pounds, temperatures in the preferred range of 575 to 625F are used.
It has been found that generally acceptable 20 average composition to conductor adhesion values have been obtained when using conduc-tor preheat temperatures in the range of 450 to 650F. The lower end of this range is somewhat less than that disclosed in the hereinbefore identified Application Serial No. 207,153 in which the composition included 3 to 10 and preferably 7 parts by weight, per 100 parts by weight of PVC, of a brominated epoxy resin.
Since that constituent included 48% bromine, less epoxide radials were present. With the non-brominated epoxy resin more epoxy groups are present for the same number of parts.
Hence, lower preheat temperatures could be used when compounding the same number of parts of the epoxy resin or less parts could be used with a higher preheat range.
Tests have shown that the adhesion varies with respect to the conductor preheat temperature. There is a critical lower limit below which the adhesion begins a generally rapid decline with non-reproducible results. As an example, insulation extruded over conductors 10-10 preheated to generally below 450F was found to be capable of being pulled manually from the conductors.
There is also an upper limit~of temperature beyond which` the adhesion values are affected adversely by the thermal degradation of the insulation. It has also been found that after a conductor preheat temperature of approximately 650 F, the adhesion of the insulation to the conductor decreases. Apparently, conductor preheat tempera-tures in excess of 650F causes the bonding process herein-before described to become less effective. If the epoxy resin constituent is subjected to this excessive heat upon engaging the conductor 10, the bond between the conductor and the insulation can become~degraded.
In order to test the adhesion of the composition to the conductors 10-10, the plastic covered drop wire 12 is subjected to what is referred to as a slip-bff test.
This test is described in detail in the hereinbefore-referred-to Application Serial No. 207,153. This test measures in pounds the force applied parallel to the axis of the conductors 10-10 and which is required to pull a 3/8 inch length of insulation from one end of the conductor. The applied force at which the insulation is pulled off the ~ -conductor is recorded and is determined to be the magnitude of adhesion of the composition to the conductor.
'.
;
1049'769 The drop wire 12 is also subjected to a compression test, an elongation test, low temperature flexibility, clamp holding and impact tests, all of which are described in the aforementioned Application Serial No. 207,153.
The following examples illustrate various flexible PVC insulation compositions prepared in accordance with the invention. The examples are summarized in Table I and are set forth in tabular form. For comparison purposes, all examples set forth were carried out using the homopolymer described hereinbefore. ~oreover, all amounts are in parts by weight.
TABLE I
Exam~les Ranges Constituent A B C D
100 PVC Resin 100 100 100 100 3-10 Epoxy Resin 7 7 10 4 55-66 Phthalate Plasticizers66 60 55 66 3-7 Metallic Stabilizer 5 3 7 5 3-5 Antimony Trioxide 3 5 4 3 1-3 Carbon Elack 2.5 3 1 2.5
5-35 Fillers CaCO3 15 10 Fumed Silica 5 5 0 5 Calcined Clay 5 10 10 5 It has been found that the composition set forth in Example A provides a drop wire 12 having the most preferred characteristics.
E~ample A
In the preferred composition, 7.0 parts of a non-bromin~ted unmodified epoxy resin ~epoxide equivalent . ~
- `
1049'769 typically 190), obtained from commercial sources, and produced as the condensation product of epichlorohydrin and Bisphenol, 100 parts, by weight, of a polyvinyl chloride resin, GP5-00003-ASTM-D1755, 66.0 parts, by weight, of mixed N-octyl, n-decyl phthalate, 5.0 parts by weight, of lead silicate sulfate stabilizer, 5 parts, by weight, of fumed silica and 5 parts by weight of calcined clay, 3.0 parts, by weight, of antimony trioxide and 2.5 parts, by weight, of carbon black, were mixed together and extruded over conductors preheated to a temperature of 600F.
Example B
The procedure of Example A was repeated with the exception that 7 parts by weight of the non-brominated unmodified epoxy resin, 60 parts bf the plasticizers, 3 parts of the metallic stabilizer, 5 parts of the antimony trioxide, 3 parts of carbon black, 15 parts of calcium carbonate, 5 parts of fumed silica and ten parts of calcined clay were employed. The reaction mixture was extruded ; about conductors 10-10 preheated to a temperature of approximately 600 F. The adhesion values of the reaction product to the conductors were similar to those obtained for Example A.
Example C
The procedure o~ Example A was repeated but with the use of 10 parts of epoxy resin, 55 parts of a phthalate plasticizer, 7 parts of a metallic stabilizer, ~ parts of an antimony trioxide, 1 part of carbon black, 10 parts each of calcium carbonate and calcined clay as fillers.
Example D
The procedure of Example A was repeated but instead using ~ parts by weight per 100 parts by weight of the PVC of the epoxy resin. While the preferred example -22~
~0497S9 employs an epoxy resin having an epoxide equivalent typical-ly of l90, it has been found -that epoxy resins in the solid class IV produce acceptable results. For example, an epoxy resin which is the trademark product of Celanese Company and designated "Epi-Rez" 522C has been used in the reaction mixture.
Testing The plastic drop wire insulation composition must possess specified properties, some of which have been described hereinbefore. The following tables indicate the properties of a composition having the composi-tion designated Example A in Table I:
TABLE II - Example A Tests Property Results Method of Test . .
Adhesion in lbs. > 12 Strip 3/8" length of insula-tion from a single conductor Compression in lbs. > 850 Load required to cursh insulation Elongation New % ~ 250 ASTM D470 Aged % ~ 200 ASTM D470 - 48 hrs.
at 212 t 2F
Clamp Holding Pass 290 lbs. static load for 24 hrs. without rupture Low Temp. Impact Pass 40 inchOpounds and -20 + 2 F
Wrap Test Pass 3/8" Mandrel and -30 + 2F
Water Immersion Tests Insulation Resistance (Megohms-lO00 fO.)~ 200 Megohm Bridge Corrected to 60 F
- Mutual Capacitance (Micro-Farads/1000 ft.) ~ 0.040 Measured at l.0 KHz frequency using auto-matic bridge unit and associated components , 1(~49'76~
TABLE III
Test Results for Example A
Preheat Temp. of 400450 500575 600625 650::
Wire (F) Average Adhesion of Reaction Product 8.5 1616.5 2122.5 21 23 to Conductors (Lbs.) :: Wire preheat temperatures in excess of 650F tend to have a degarding effect on the insulation composition. Moreover, wire preheat temperatures beyond 650F undesirably require extended cooling before being advanced in engagement with sheaves.
It is to be understood that the above described ;~
arrangements are simply illustrative of the invention.
Other arrangemen-ts may be devised by those skilled in the ar-t which will embody the principles of the invention to fall within the spirit and scope thereof.
.
E~ample A
In the preferred composition, 7.0 parts of a non-bromin~ted unmodified epoxy resin ~epoxide equivalent . ~
- `
1049'769 typically 190), obtained from commercial sources, and produced as the condensation product of epichlorohydrin and Bisphenol, 100 parts, by weight, of a polyvinyl chloride resin, GP5-00003-ASTM-D1755, 66.0 parts, by weight, of mixed N-octyl, n-decyl phthalate, 5.0 parts by weight, of lead silicate sulfate stabilizer, 5 parts, by weight, of fumed silica and 5 parts by weight of calcined clay, 3.0 parts, by weight, of antimony trioxide and 2.5 parts, by weight, of carbon black, were mixed together and extruded over conductors preheated to a temperature of 600F.
Example B
The procedure of Example A was repeated with the exception that 7 parts by weight of the non-brominated unmodified epoxy resin, 60 parts bf the plasticizers, 3 parts of the metallic stabilizer, 5 parts of the antimony trioxide, 3 parts of carbon black, 15 parts of calcium carbonate, 5 parts of fumed silica and ten parts of calcined clay were employed. The reaction mixture was extruded ; about conductors 10-10 preheated to a temperature of approximately 600 F. The adhesion values of the reaction product to the conductors were similar to those obtained for Example A.
Example C
The procedure o~ Example A was repeated but with the use of 10 parts of epoxy resin, 55 parts of a phthalate plasticizer, 7 parts of a metallic stabilizer, ~ parts of an antimony trioxide, 1 part of carbon black, 10 parts each of calcium carbonate and calcined clay as fillers.
Example D
The procedure of Example A was repeated but instead using ~ parts by weight per 100 parts by weight of the PVC of the epoxy resin. While the preferred example -22~
~0497S9 employs an epoxy resin having an epoxide equivalent typical-ly of l90, it has been found -that epoxy resins in the solid class IV produce acceptable results. For example, an epoxy resin which is the trademark product of Celanese Company and designated "Epi-Rez" 522C has been used in the reaction mixture.
Testing The plastic drop wire insulation composition must possess specified properties, some of which have been described hereinbefore. The following tables indicate the properties of a composition having the composi-tion designated Example A in Table I:
TABLE II - Example A Tests Property Results Method of Test . .
Adhesion in lbs. > 12 Strip 3/8" length of insula-tion from a single conductor Compression in lbs. > 850 Load required to cursh insulation Elongation New % ~ 250 ASTM D470 Aged % ~ 200 ASTM D470 - 48 hrs.
at 212 t 2F
Clamp Holding Pass 290 lbs. static load for 24 hrs. without rupture Low Temp. Impact Pass 40 inchOpounds and -20 + 2 F
Wrap Test Pass 3/8" Mandrel and -30 + 2F
Water Immersion Tests Insulation Resistance (Megohms-lO00 fO.)~ 200 Megohm Bridge Corrected to 60 F
- Mutual Capacitance (Micro-Farads/1000 ft.) ~ 0.040 Measured at l.0 KHz frequency using auto-matic bridge unit and associated components , 1(~49'76~
TABLE III
Test Results for Example A
Preheat Temp. of 400450 500575 600625 650::
Wire (F) Average Adhesion of Reaction Product 8.5 1616.5 2122.5 21 23 to Conductors (Lbs.) :: Wire preheat temperatures in excess of 650F tend to have a degarding effect on the insulation composition. Moreover, wire preheat temperatures beyond 650F undesirably require extended cooling before being advanced in engagement with sheaves.
It is to be understood that the above described ;~
arrangements are simply illustrative of the invention.
Other arrangemen-ts may be devised by those skilled in the ar-t which will embody the principles of the invention to fall within the spirit and scope thereof.
.
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A composition of matter capable of being extruded and which includes a mixture comprising 100 parts by weight of a polyvinyl chloride homopolymer; 3 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichloro-hydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of 170 to 800; 55 to 66 parts by weight per 100 parts by weight of polyvinyl chloride of a phthalate plasticizer; 3 to 7 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 1 to 3 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; and 5 to 35 parts by weight per 100 parts of the polyvinyl chloride of a filler constituent.
2. The composition of claim 1, wherein the epoxy resin is a liquid and has a weight per epoxy equivalent in the range of 170 to 200.
3. The composition of claim 1, wherein the epoxy resin is a solid and has a weight per epoxy equivalent in the range of 280 to 800.
4. The composition of claim 1, wherein the filler con-stituent includes 5 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
5. The composition of claim 1, wherein the filler con-stituent includes 15 parts by weight per 100 parts by weight of the polyvinyl chloride of calcium carbonate, 5 parts by weight per 100 parts by weight of the polyvinyl chloride of fumed silica and 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
6. The composition of claim 1, wherein the filler con-stituent includes 5 parts by weight per 100 parts by weight of the polyvinyl chloride of fumed silica and 5 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
7. The composition of claim 1, wherein the filler constit-uent includes 10 parts by weight per 100 parts by weight of the polyvinyl chloride of calcium carbonate and 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
8. A composition of matter capable of being extruded and which includes a mixture which comprises 100 parts by weight of a polyvinyl chloride homopolymer, 7 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichloro-hydrin and Bisphenol A, having a weight per epoxy equivalent of approximately 190; 66 parts by weight per 100 parts by weight of polyvinyl chloride of a phthalate plasticizer; 5 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 2.5 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; 5 parts by weight per 100 parts of the polyvinyl chloride of fumed silica and 5 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
9. An elongated member having at least one conductor covered with an extruded insulative composition of matter which includes a reacted mixture comprising 100 parts by weight of polyvinyl chloride homopolymer; 3 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichloro-hydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of 170 to 800; 55 to 66 parts by weight per 100 parts by weight of polyvinyl chloride of a phthalate plasticizer; 3 to 7 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 1 to 3 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; and 5 to 35 parts by weight per 100 parts of the polyvinyl chloride of a filler constituent.
10. The elongated member of claim 9, wherein the epoxy resin is a liquid form and has an epoxide equivalent in the range of 170 to 200.
11. The elongated member of claim 9, wherein the epoxy resin is a solid form and has an epoxide equivalent in the range of 280 to 800.
12. The elongated member of claim 9, wherein the filler constituent includes 5 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
13. The elongaged member of claim 9, wherein the filler material includes 15 parts by weight per 100 parts by weight of the polyvinyl chloride of calcium carbonate, 5 parts by weight per 100 parts by weight of the polyvinyl chloride of fumed silica and 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
14. The elongaged member of claim 9, wherein the filler material includes 5 parts by weight per 100 parts by weight of polyvinyl chloride of fumed silica and 5 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
15. The elongated member of claim 9, wherein the filler material includes 10 parts by weight per 100 parts by weight of the polyvinyl chloride of calcium carbonate and 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
16. An elongated transmission member having at least one conductor covered with an extruded insulative composition of matter and which includes a reacted mixture which comprises 100 parts by weight of polyvinyl chloride homopolymer; 7 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensation of epichlorohydrin and Bisphenol A, having a weight per epoxy equivalent of approximately 190; 66 parts by weight per 100 parts by weight of polyvinyl chloride of a phthalate plasticizer;
5 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 2.5 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; 5 parts by weight per 100 parts of the polyvinyl chloride of fumed silica and 5 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
5 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 2.5 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; 5 parts by weight per 100 parts of the polyvinyl chloride of fumed silica and 5 parts by weight per 100 parts by weight of the polyvinyl chloride of a calcined clay.
17. A method of covering a conductive member which includes the steps of advancing the conductive member along a path and contacting the member while the member is maintained at a suitable temperature with a reaction mixture comprising 100 parts by weight of a polyvinyl chloride homopolymer; 3 to 10 parts by weight per 100 parts by weight of the polyvinyl chloride of a non-brominated epoxy resin based on the condensa-tion of epichlorohydrin and Bisphenol A, having a weight per epoxy equivalent approximately in the range of 170 to 800; 55 to 66 parts by weight per 100 parts by weight of polyvinyl chloride of a phthalate plasticizer; 3 to 7 parts by weight per 100 parts by weight of polyvinyl chloride of a metallic stabilizer; 3 to 5 parts by weight per 100 parts by weight of the polyvinyl chloride of antimony trioxide; 1 to 3 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent; and 5 to 35 parts by weight per 100 parts of the polyvinyl chloride of a filler constituent, to form an adherent coating on the conductive member comprising a reaction product of the reaction mixture.
18. The method of claim 17 wherein the suitable tempera-ture range is approximately 575°F to 625°F and the reaction mixture includes 100 parts by weight of a polyvinyl chloride homopolymer; 7 parts by weight per 100 parts by weight of the polymeric material of a non-brominated epoxy resin based on the condensation of epichlorohydrin and Bisphenol A, having a weight per epoxy equivalent of approximately 190; 66 parts by weight per 100 parts by weight of the polyvinyl chloride of a phthalate plasticizer; 5 parts by weight per 100 parts by weight of the polyvinyl chloride of a metallic stabilizer, 5 parts by weight per 100 parts by weight of the polyvinyl chloride of fumed silica; 5 parts by weight per 100 parts by weight of polyvinyl chloride of a calcined clay; 3 parts by weight per 100 parts by weight of the polyvinyl chloride of the antimony trioxide;and 2.5 parts by weight per 100 parts by weight of the polyvinyl chloride of a carbon black constituent.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US51526674A | 1974-10-16 | 1974-10-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1049769A true CA1049769A (en) | 1979-03-06 |
Family
ID=24050648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA228,101A Expired CA1049769A (en) | 1974-10-16 | 1975-05-30 | Electrical insulation composition and covering conductors therewith |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS583327B2 (en) |
| BE (1) | BE834485A (en) |
| CA (1) | CA1049769A (en) |
| DE (1) | DE2546102C2 (en) |
| ES (1) | ES441852A1 (en) |
| FR (1) | FR2331129A1 (en) |
| GB (1) | GB1527764A (en) |
| IT (1) | IT1043385B (en) |
| MX (1) | MX3725E (en) |
| NL (1) | NL7512099A (en) |
| SE (1) | SE427317B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8101201A (en) * | 1981-03-12 | 1982-10-01 | Philips Nv | MOISTURE-RESISTANT TEMPERATURE SENSOR ON PVC CABLE. |
| GB2163895A (en) * | 1984-09-01 | 1986-03-05 | Fothergill Cables Limited | A cable and a method of producing same |
| JP2698978B2 (en) * | 1988-02-17 | 1998-01-19 | 三菱化学エムケーブイ株式会社 | Vinyl chloride resin composition |
| GB2275565A (en) * | 1993-02-18 | 1994-08-31 | Continental Conair Limited | An electric cable |
| BR9802508A (en) * | 1997-11-11 | 1999-09-08 | Servicios Condumex Sa | Formulation of heavy metal-free polyvinyl chloride compounds for thin-walled automotive primary cable insulation |
| JP2016084449A (en) * | 2014-10-29 | 2016-05-19 | 住友電気工業株式会社 | Abrasion resistant chlorine-based polymer composition and chlorine-based polymer coated cable |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3579608A (en) * | 1968-08-26 | 1971-05-18 | Bell Telephone Labor Inc | Wire coating of brominated diglycidyl ether of bisphenol a and polyvinyl chloride |
-
1975
- 1975-05-30 CA CA228,101A patent/CA1049769A/en not_active Expired
- 1975-10-09 GB GB41357/75A patent/GB1527764A/en not_active Expired
- 1975-10-09 SE SE7511345A patent/SE427317B/en unknown
- 1975-10-14 BE BE160914A patent/BE834485A/en not_active IP Right Cessation
- 1975-10-15 NL NL7512099A patent/NL7512099A/en not_active Application Discontinuation
- 1975-10-15 IT IT28305/75A patent/IT1043385B/en active
- 1975-10-15 FR FR7531598A patent/FR2331129A1/en active Granted
- 1975-10-15 DE DE2546102A patent/DE2546102C2/en not_active Expired
- 1975-10-16 ES ES441852A patent/ES441852A1/en not_active Expired
- 1975-10-16 JP JP50123892A patent/JPS583327B2/en not_active Expired
- 1975-10-16 MX MX752049U patent/MX3725E/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| MX3725E (en) | 1981-05-27 |
| FR2331129B1 (en) | 1980-04-18 |
| BE834485A (en) | 1976-02-02 |
| SE427317B (en) | 1983-03-21 |
| JPS583327B2 (en) | 1983-01-20 |
| AU8564075A (en) | 1977-04-21 |
| GB1527764A (en) | 1978-10-11 |
| DE2546102C2 (en) | 1982-05-19 |
| SE7511345L (en) | 1976-04-20 |
| NL7512099A (en) | 1976-04-21 |
| JPS51125444A (en) | 1976-11-01 |
| DE2546102A1 (en) | 1976-04-29 |
| FR2331129A1 (en) | 1977-06-03 |
| ES441852A1 (en) | 1977-03-16 |
| IT1043385B (en) | 1980-02-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1052513A (en) | Method of manufacturing an insulated conductor and product produced thereby | |
| US8017710B2 (en) | Crosslinkable high pressure polyethylene composition, a process for the preparation thereof, a pipe and a cable prepared thereof | |
| US4451536A (en) | Heat distortion-resistant thermoplastic semi-conductive composition | |
| US3579608A (en) | Wire coating of brominated diglycidyl ether of bisphenol a and polyvinyl chloride | |
| CA1049769A (en) | Electrical insulation composition and covering conductors therewith | |
| EP1528574B1 (en) | Low voltage power cable with insulation layer comprising polyolefin having polar groups | |
| US4666642A (en) | Method of forming shaped article from a fluorocarbon polymer composition | |
| US4541980A (en) | Methods of producing plastic-coated metallic members | |
| US5527612A (en) | Fluorocarbon copolymer-insulated wire | |
| US4598127A (en) | Compositions based on mixtures of ethylene-ethyl acrylate copolymers and ethylene-vinyl acetate-vinyl chloride terpolymers | |
| CA1063762A (en) | Manufacturing an insulated conductor and the article produced thereby | |
| EP0210425A2 (en) | Compositions based on mixtures of ethylene-ethyl, acrylate copolymers and ethylene-vinyl acetate-vinyl chloride terpolymers | |
| US3334063A (en) | Insulating material | |
| US4610909A (en) | Plastic-coated metallic member | |
| KR800000094B1 (en) | Electrical insulation composition and covering conductors therewith | |
| KR20220130368A (en) | Composition for optical cable jacket, optical cable jacket and optical cable manufactured using the same | |
| US4612233A (en) | Plastic-coated metallic members | |
| CA1151255A (en) | Electrical insulated wire with flexibility and abrasion-resistant layer | |
| CN101540216A (en) | 150 DEG C irradiation cross-linked computer cable and method for manufacturing same | |
| KR100947141B1 (en) | Semiconducting polyvinyl chloride composition and electric cable using the same | |
| JPH06103824A (en) | Wear resistant and heat resistant insulated electric cable | |
| CN101540219B (en) | 125 DEG C irradiation cross-linked power cable and method for manufacturing same | |
| JPH05303909A (en) | Insulated electric wire | |
| CN114672108A (en) | Rubber sleeve cable three-layer co-extrusion external shielding strippable material and preparation method thereof | |
| KR20050043163A (en) | Halogenfree and flame retardant xlpo composition and method for preparing thereof |