FIRE RETARDANT WIRE COATING

BACKGROUND OF THE INVENTION

mid block B is present in the block copolymer. The copolymer may be either linear or branched in structure and mixtures of such configuratipns may be employed. Blocks A comprise predominantly polymer blocks of at least one monoalkenyl arene while blocks B comprise predominantly hydrogenated polymer blocks of at least one conjugated diene. Moreover, blocks A are characterized in that no more than 25% of the original aromatic double bonds are reduced by hydrogenation while blocks B are characterized by having at least 75% of their aliphatic double bonds reduced by hydrogenation. It is possible, in fact, to prepare block copolymers in which the blocks B are poly(alphamonoolefin) blocks which are regarded here as being substantially equiva

Various materials have been utilized in the past for 5 coating and insulating electrical conductors. Among the more commonly used coatings are the conventional enamel or resinous varnish-type coatings, polyvinyl resins, polystyrene resins, etc. All these coating compositions, while providing insulation, have been found to 10 be lacking in one respect or another or to inherently involve certain disadvantages. For example, the enamel or varnish coatings lack adequate flexibility. Rubber coatings such as polybutadiene, ethylene-propylene rubbers, and natural rubber require vulcanization in 1'5 lent to substantially completely hydrogenated polymer order to obtain their maximum desired set of physical blocks of conjugated dienes. The remaining specificaproperties. Furthermore, most rubber coatings deteriorate with age and exposure to the atmosphere, resulting in the cracking and peeling of the rubber coatings. The polyvinyl and polystyrene resin coatings must be plasti- 20 cized in order to have sufficient flexibility. Such coatings often lose plasticizers during aging and then become brittle.

Recent improvements in the art of polymerization have enabled the production of certain block copoly- 25 polymer block. When the diene employed is butadiene, mers which have been found to be eminately suitable it is prefered that polymerizaton conditions be adjusted

to result in a polymer block having from about 35 to about 55% 1,2 structure. Thus, when such a block is hydrogenated, the resulting product is, or resembles, a 30 regular copolymer block of ethylene and butene-1 If the conjugated diene employed is isoprene, the resulting hydrogenated product is or resembles a regular copolymer block of ethylene and propylene (EP). See generally U.S. Pat. No. 3,595,942. A novel fire-resistant polymer composition has been 35 For simplicity, reference will be made to several basic found that is very suitable for the coating of electrical

tion and the claims are meant to include within their scope these alphamonoolefin equivalents of fully hydrogenated polymer blocks of conjugated dienes.

Blocks A are prepared by block polymerization of such monomers as styrene, alphamethyl styrene, tertbutyl styrene and vinyl toluene. Blocks B are prepared by block polymerization of conjugated dienes such as butadiene or isoprene and thereafter hydrogenating the

for electrical conductor coatings in view of their unexpectedly superior set of electrical properties combined with their superior physical properties. However, these coatings, such as the coatings disclosed in U.S. Pat. No. 3,639,163, lack sufficient fire resistance to be useful in many desirable applications.

SUMMARY OF THE INVENTION

conductors for use in high temperature service. This composition comprises a selectively hydrogenated block copolymer, an extending oil, polymeric alpha-olefin, fire retardant, and as the inorganic filler, calcium 40 sulfate. Compositions employing calcium sulfate in place of other fillers such as clay, silicates, and calcium carbonate have much improved fire retardant properties.

DETAILED DESCRIPTION OF THE
INVENTION

The present invention is a fire-resistant polymer composition comprising:

45

50

a. 100 parts by weight of a block copolymer having at least two polymer end blocks A and at least one polymer mid block B, each block A being a non-elastomeric polymer block of a monoalkenyl arene having an average molecular weight of between about 2,000 and 55 about 125,000 and each block B being an elastomeric hydrogenated polymer block of a conjugated diene, having an average molecular weight between about 10,000 and about 250,000;

b. 0-200 parts by weight of an extending oil;

c. 10-300 parts by weight of a polymeric alpha-olefin;

d. 5-100 parts by weight of antimony trioxide;

e. 25-200 parts by weight of a chlorinated hydrocarbon; and

f. 50-300 parts by weight of a calcium sulfate filler. The block copolymers contemplated for use in these

compositions have two essential types of blocks, A and B. At least two end blocks A are present and at least one

types of block copolymers especially contemplated herein. However, it will be understood that block copolymers may be prepared by coupling polymeric lithium carbanions, some of which may leave coupling agent residues. Linear as well as branched multi-block structures also are contemplated. The methods are known in the art of synthesizing both linear and branched block copolymers, using sequential polymerization alone or sequential polymerization followed by coupling procedures.

Typical block copolymers especially contemplated are the following:

1. Polystyrene-hydrogenated polybutadiene-polystyrene.

2. Polystyrene-hydrogenated polyisoprene-polystyrene. 3. Poly(alphamethyl styrene)-hydrogenated polybutadiene-poly(alphamethyl styrene).

4. Poly(alphamethyl styrene)-hydrogenated polyisoprene-poly(alphamethyl styrene).

Each block A has an average molecular weight between about 2,000 and 125,000, preferably between about 5,000 and 50,000. Each block B has an average molecular weight between about 10,000 and 250,000, preferably between about 30,000 and 150,000. These are number average molecular weights determined by such methods as tritium counting or osmotic pressure measurements. The A block content of the block copolymer is preferably between about 20% and about 60% based on the total weight of the copolymer. The purpose of 65 the latter restriction is to promote the self-vulcanizing feature of these particular materials, which is important in maintaining the favorable electrical properties of the composition.

60
[blocks in formation]

The term "extending oils" as used in the description of this invention, broadly encompasses not only the usual extending oils for rubbers prepared from petroleum fractions but also contemplates the use of olefin oligomers and low molecular weight polymers. The petroleum derived extending oils which maybe employed include relatively high boiling materials having number average molecular weights between about 300 and 1,400. The oligomers may be polypropylenes, polybutenes, hydrogenated polyisoprene, hydrogenated polybutadiene, or the like having average molecular weights between about 350 and about 10,000. The amount of extending oil employed varies from about 0 to about 200 phr (parts by weight per hundred parts by weight of rubber), preferably about 50 to about 100 phr.

The polymeric alpha-olefin component is preferably isotactic polypropylene, which is an essentially crystalline polypropylene. The solid isotactic polypropylene has weight average molecular weight of between about 200,000 and about 300,000, preferably between about 225,000 and about 275,000. The mount of polymeric alpha-olefin employed typically varies from about 10 to about 300 phr, preferably about 50 to about 150 phr.

The antimony trioxide component (SbaOs) is essential for flame retardance reasons and may be produced in any suitable process. The amount of antimony trioxide employed varies from about 5 to about 100 phr, preferably about 10 to about 30 phr.

The chlorinated hydrocarbon employed is preferably a fire retardant compound derived from hexachlorocyclopentadiene (HEX). One of the derivatives employed, and adduct of HEX, is perchloropentacyclodecane, which is typically produced by the aluminum chloridecatalyzed dimerization of hexachlorocyclopentadiene in a chlorinated solvent. This dimer is commercially available from Hooker Chemical Company under the tradename DECLORANE 510.

Another adduct employed in the instant composition is the Diels-Adler product made by adding 2 moles of 40 hexachlorocyclopentadiene to one mole of the stable cis-isomer of 1,5-cyclooctadiene. The structure of the adduct is:

10

15

20

25

30

35
[blocks in formation]

One method to prepare the compound is disclosed in U.S. 3,385,819. This adduct is commercially available from Hooker Chemical Company under the tradename 55 DECHLORANE® Plus 25 and 515.

The quantity of the chlorinated hydrocarbon employed varies from about 25 to about 200 phr, preferably from about 25 to about 100 phr.

An essential component of the instant invention is a 60 calcium sulfate filler. The term "calcium sulfate" encompasses not only the anhydrous salt, CaSO4, but also includes its two hydrates-the dihydrate, CaSO4 X 2H2O, and the hemihydrate, CaSO4 X O.SttjO. The principal commercial forms are gypsum, the naturally occuring 65 dihydrate; plaster of Paris, the hemihydrate, formed by calcining gypsum; and anhydrate, CaS04, occuring as a mineral and prepared in both insoluble and soluble

forms by dehydration of gypsum. Preferably, the anhydrate CaSO4 is employed as the inorganic filler.

The calcium sulfate may be obtained from a variety of sources. Among the various sources are gypsum, alabaster, selenite, satin spar, anhydrite, gypsite and gypsum sands. See generally Kirk-Othmer Encyclopedia of Chemical Technology, Volume 4, pages 14-27 (second edition, 1967).

The amount of calcium sulfate filler employed varies from about 50 to about 300 phr, preferably about 150 to about 250 phr.

Other additives such as pigments, extenders, antioxidants, u.v. stabilizers, and other fire retardants may also be added. The additives that can be incorporated should be selected from those whose electrical properties are such as will not materially reduce or impair the electrical properties of the composition. The amount of such additives included in the composition will, of course, depend upon the particular block copolymer being employed and the ultimate use being made of the composition.

The various components may be combined in any suitable manner including solution blending, melt blending, and dry blending. The compositions of the present invention may then suitably be employed as wire coatings. These compositions are especially superior for use as insulators for electrical conductors not only because of their superior electrical properties, but also for their high degree of adherence to metallic surfaces without special treatment of such surface. The electrical conductors usually employed with the instant compositions are metallic wires such as copper, silver, aluminum, and alloys thereof.

The invention is further illustrated by reference to the following Illustrative Embodiments, which are presented for the purpose of illustraton only, and the invention is not to be limited to the particular ingredients and operating conditions disclosed.

ILLUSTRATIVE EMBODIMENT I

In Illustrative Embodiment I, four wire coating compositions were formulated and extrusion coated on an 18 AWG bare copper wire (0.030 inch coating). In each case, the block polymer employed was a selectively hydrogenated styrene-butadiene-styrene block copolymer (SEES). Other common ingredients included a rubber compounding oil, polypropylene resin, antioxidant package [Plastonox 2246 (2,2'methylenebis (4methyl-6-tertiarybutyl phenol) and Plastonox DLTDP (di-lauryl thiodipropionate)], and two fire retardants antimony trioxide and Dechlorane Plus 25 chlorinated hydrocarbon.

In composition number 1, a talc filler was employed, while in composition number 2, a clay filler was employed. The filler in composition number 3 was CamelCARB, a calcium carbonate filler. In composition number 4, the filler was anhydrous CaSO4 obtained from United States Gypsum under the tradename, SNOW WHITE filler.

These various wire coatings were subjected to a standard vertical flame test according to the method of UL-83. Only the CaSO4-filled composition was selfextinguishing, the other three formulations were not self-extinguishing.

The various compositions in parts by weight are presented below in Table 1.
[table]

4,038,237

10

What is claimed is:

1. A fire-resistant polymer composition comprising: a. 100 parts by weight of a block copolymer having at least two polymer end blocks A and at least one polymer mid block B, each block A being a non- 20 elastomeric polyer a monoalkenyl arene having an average, molecular weight of between about 2,000 and about 125,000 and having no more than 25% of the aromatic double bonds being reduced by hydrogenation, and each block B being an elastomeric 25 hydrogenated polymer block of a conjugated diene, having an average molecular weight between about 10,000 and about 250,000;

30

35

40

45

50

55

60

b. 0-200 parts by weight of an extending oil;

c. 10-300 parts by weight of a polymeric alpha-olefin;

d. 5-100 parts by weight of antimony trioxide;

e. 25-200 parts by weight of a chlorinated hydrocarbon; and

f. 50-300 parts by weight of a calcium sulfate filler.

2. A composition according to claim 1 wherein the calcium sulfate filler is selected from the group consisting of the anhydrous salt, CaSO4; the dihydrate, CaSO4 X 2H2O; the hemihydfate, CaSO4 X 0.5H2O; and mixtures thereof.

3. A composition according to claim 1 wherein the calcium sulfate employed is the anhydrous salt CaSO4.

4. A composition according to claim 1 wherein the A block is styrene and the conjugated diene is butadiene.

5. A composition according to claim 1 wherein the polymeric alpha-olefin is isotactic polypropylene.

6. A composition according to claim 1 wherein the chlorinated hydrocarbon is an adduct of hexachlorocyclopentadiene.

7. A composition according to claim 1 where the amount of extending oil varies from about 50 to about 100 parts by weight.

8. A composition according to claim 1 wherein the molecular weight of the A blocks are between about 5,000 and 50,000 and the molecular weight of the B blocks are between 30,000 and 150,000.




Coating to protect against external influences, or to beautify the appearance of the surfaces of objects covering the operation of another substance. Kaplamacılıkta as a means of coating used in many procedures.
Metal coating: metal or non-metallic anti-corruption bodies, surfaces or abrasion-resistant metal covered many times. Cleaned and prepared before the coated surface. Coating process, spraying, dipping, diffusion, gas and vacuum is performed within the means of condensation.
Surrface Preparation: Before the coating process of organic and inorganic contaminants and oxide layers coated surfaces must be cleaned thoroughly. For this, the metal surface, immersed in the appropriate solvent or solvents to clean the surface by spraying the surface of foreign substances. Alkaline detergent is used according to the type of dirt or acid solutions. If necessary, they will contribute to the high pressure injection into the corrosive salts utilized fine. Electrolysis method may be applied. Oxide layer of steel and removal of 65-85 ° C temperature reduction as a matter of 15% 10-sulfate acid (H2SO4) solution or dilute hydrochloric acid at 20 ° C is used.

Mechanical cleaning: Aluminum oxide or silicon carbide abrasive stone and dust, sand paper or cloth surface to smooth and covered by dirt, foreign material removed. The surface is sprayed with steam under pressure, or abrasive powders or etching the surface of a rotating drum is provided in the covered parts.

Chemical cleaning: This method of acid etched metal surfaces, dağlanır, chemical or electrochemical polished way. Copper surfaces are usually persulphates, chromate compounds, or salts of iron oxide by using three dağlanır. Chemical polishing of zinc and aluminum, such as nitric and phosphoric acid is carried out by immersion into a strong oxidizing acid solutions. Electro-polishing of the aluminum, iron, steel, stainless steel, zinc, various alloys, electrolytic copper anode connects to the bathroom.

Metal Coating Operations

Injection: In case the corresponding metal or metal alloy powder or wire coated with a gun to the surface is sprayed is melted. Spray coating through the two most widely used metals, zinc and aluminum. More liquid metal spray tanks, used for coating of steel structures in place.

Hot-dip: coated metal surface, after cleaning the molten metal daldırlarak surface diffusion (diffusion) through the coating is provided. For this purpose, as metal coatings, zinc, tin, lead and aluminum is used. Steel, zinc is dipped galvanized. Zinc can also be used instead of tin. Thin sheets of iron from tin cans are immersed. To avoid surface oxidation during the process, the appropriate fluxes, using the surface air in contact with hydrogen or inert gases are cut off.

Cementation or diffusion coating: coated metal, put into powder coating the metal is heated to be used. Environment oxidation, anti-substances in contact with air, inert gases are kept. For example, with a metal coating of aluminum diffusion of the means by which metal parts kalorizasyon process, in which the aluminum powder is placed in a rotating drum. Sementasyonunda iron temperature is 850 ° -950 ° C. This way of iron with zinc kaplanmasına şerardizasyon (shererdization) is called. Chrome plating is done with it is called kromizasyon.

Pin (Percussion), coating (Peen plating): coated metal parts, metal powders used in coating solution and an activator in conjunction with a rotary drum is placed inside. There is also the effect of metal parts falling within the pulse of the drum. Washer (washer), nails, small pieces of chain with this method, such as zinc, brass and is coated with cadmium.

Gas coating: Coating of metal used for the gaseous compound, usually carbonyl, while the coated object is heated body. Hot on the surface of metal atoms separated from the gaseous compound is collected on the surface. This procedure than chromium and iron-plated nickel coating can be sometimes.

Vacuum condensation: this method of casting metals and plastics can be coated with metal. To be used for coating metal is evaporated in vacuum by heating with tungsten heater. Track surface is coated, cleaned, adjusted and polished the metal vapor within the cell are rotated. Metal vapor condenses on the surface of the cold part. Aluminum, gold, silver and other metals buharlaştırılabilen used for this purpose. This is not sort of wear-resistant coatings, also coated with a lacquer.

Chemical reduction through the coating (Electroless): Water-soluble silver, gold and copper salts in an aqueous medium with a strong reducing effect through the reduction of the glass (as in the construction of the mirror), plastics and metals can be covered.

Chemical coating by means of substitution: Fields, the displacement solution through the copper, gold, silver and coated with tin. Coating thickness is very thin (2.5 x10-6 mm).

Plated by electrolysis (Electroplating): coated metal or plastic track surface was made conductive, the metal salt solution used for coating in the cathode connected to the metal cations, coated on the surface by the accumulation is performed by passing an electric current. (See Electrolysis)

One of about 33 with the metal, in aqueous solutions, electrolysis can be plated. Other metals plated with molten salts or organic electrolytes to do is electrolysis. The coating of metal with about 15 commercial purposes. Some of these are: Copper, silver, zinc, gold, platinum, cadmium, tin, lead, chromium and nickel