JPS6140256B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention comprises an alkylene-alkyl acrylate copolymer, a halogenated flame retardant, and 20 to about 30% by weight.
of magnesium or calcium oxides, carbonates, hydroxides or sulfates and having improved flame retardancy and reduced gas evolution upon combustion. The compositions of the present invention are particularly useful as jacket materials around industrial control cables and telephone wires and cables, and as insulation around electrical conductors. Compositions based on olefin polymers, such as alkylene-alkyl acrylate copolymers, are known for their beneficial physical and electrical properties.
It has been proposed for use in a variety of industrial applications. For example, alkylene-alkyl acrylate copolymers are corrosion resistant, tenacious, and wear resistant. Accordingly, alkylene-alkyl acrylate copolymers may be used in compositions intended for use as jacket materials around industrial control cables and telephone wires and cables, and as insulation around electrical conductors. was suggested. Alkylene-alkyl acrylate copolymer is
Alkylene-alkyl acrylate copolymers have the disadvantage of being flammable, although they have properties that make them desirable for use in compositions intended for use as jacket materials and as insulators as previously described. I am troubled by this. In order to make these copolymers flame retardant and to reduce the rate of gas evolution during combustion, they are halogenated as described in my U.S. Patent Application Nos. 127509 and 944336. Flame retardants and alkaline earth metal salts or bases were added. The compositions disclosed in these U.S. patent applications are industrially attractive systems that are flame retardant, do not produce thick smoke upon combustion, and do not produce high levels of acidic and corrosive gases. . In view of today's increasingly stringent industrial standards and increasingly stringent government regulations, materials that are characterized by high levels of flame retardancy and by the absence of unacceptable deterioration of the other desirable properties listed above. There is an urgent need for such compositions. The present invention provides compositions that meet the need for improved flame retardancy while maintaining acceptable standards for other desirable properties. Compositions of the present invention useful for the above-described applications include a normally solid alkylene-alkyl acrylate copolymer and from about 1 to about 30% by weight of a halogenated flame retardant, preferably from about 5 to about 20% by weight. and 20 to about 30% by weight of an oxide, carbonate, hydroxide or sulfate of magnesium or calcium. The weight% is
Based on the total weight of the composition unless otherwise specified. The alkylene-alkyl acrylate copolymer of the present invention is a known compound produced by reacting alkylene with an alkyl acrylate, and usually contains about 2 to about 50% by weight of bound alkyl acrylate. do. Preferred alkylenes are ethylene, propylene,
Butene-1, isobutylene, pentene-1, 2-
Methylbutene-1, 3-methylbutene-1, hexene-1, heptene-1, octene-1 and the like. The alkylene portion of the alkylene-alkyl acrylate copolymer contains 2 to 18 carbon atoms, preferably 2 to 3 carbon atoms. Suitable alkyl acrylate monomers copolymerized with alkylene have the following formula: Within the above formula, R ¹ is hydrogen or methyl and R ² is alkyl having 1 to 8 carbon atoms. Specific compounds encompassed by this formula include methyl acrylate, ethyl acrylate, methyl methacrylate, n-butyl acrylate, t-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, and It is similar. Alkylene-alkyl acrylate copolymer is
They generally have a density (ASTMD 1505, conditioning in ASTM D 147-72) of about 0.92 to about 0.94 and a melt index (ASTM D-1237, 44 psi test pressure) of about 0.5 to about 500 dg/min. For purposes of this invention, preferred copolymers are ethylene-ethyl acrylate, generally having from about 3 to about 40% by weight bound ethyl acrylate, preferably from about 5 to about 20% by weight bound ethyl acrylate. It is a copolymer. Bound alkyl acrylates are conveniently measured by infrared analysis. Halogenated flame retardants useful for the purposes of this invention are well known to those skilled in the art. These flame retardants are
It is a halogenated (brominated or chlorinated) organic compound. Preferred halogenated organic compounds include chlorinated polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride copolymers, halogenated paraffins and paraffin waxes, chlorinated alicyclic hydrocarbons and brominated aromatic compounds. . Most preferred are decabromodiphenyl oxide and the formula Compounds such as ethylene (bis-tetrabromophthalimide) in which R is each chlorine or bromine and n is an integer from 1 to 6 are included. The calcium or magnesium oxides, carbonates, hydroxides or sulfates of the invention are commercially available in different forms and grades. Calcium or magnesium oxides, carbonates, hydroxides or sulfates can optionally be coated with a compatible hydrophobic material. Preferred coating materials are metal salts of fatty acids, organosilanes and organotitanates. Examples of metal components in salts of fatty acids fall in groups a, a or b of the periodic table (Handbook of Chemistry and Physics, 50th edition). The acid used to form the metal salt is 8
Saturated or unsaturated-basic or dibasic branched or straight chain fatty acids having ~20 carbon atoms. Such acids that may be included within the practice of this invention include, but are not limited to, palmitic, stearic, lauric, oleic, sebacic, ricinolene, parcitolein, and the like. The preferred acid is stearic acid, whereas the preferred metal salts are calcium stearate and zinc stearate. The organic silane is preferably an alkoxysilane such as alkylalkoxysilane, alkenylalkoxysilane, alkynylalkoxysilane, alkylarylalkoxysilane, alkenylarylalkoxysilane, and alkynylarylalkoxysilane. Suitable alkoxysilanes include, for example, methyltriethoxysilane,
Includes methyltris-(2-methoxyethoxy)silane, dimethyldiethoxysilane, allyltrimethoxysilane and the like. Also suitable are vinylsilanes such as vinyltris-(2-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane and the like.
If desired, the organosilane itself can be included as an additive in the composition. Exemplary suitable organotitanates fall within the following formula Ti( ^OR3 ) ₄ , where ^R3 is a hydrocarbon group. Examples of organic titanates are tetrabutyl titanate, tetraisopropyl titanate and the like. The alkaline earth metal compound may be prepared in a two-roll mill, Henschel mixer, Waring blender, and similar equipment at a concentration of from about 0.05 to about 5 parts by weight per 100 parts by weight of alkaline earth metal salt or base.
Coating can be done by mixing parts by weight of hydrophobic substances. The compositions of the present invention may contain other additives as are well known in the art, depending on the end use of the composition. For example, the composition may contain a peroxide (generally from about 0.05 to
approximately 4.0% by weight), antioxidants (generally approximately 0.01
~3.0 parts by weight, carbon black, and other additives commonly used in moldable compositions, curable compositions, compositions to be extruded into film materials, compositions to be coated, and the like. can contain. When the compositions of the invention are intended for use in wire and cable or molding applications, it is advantageous for the compositions to contain fillers. A preferred filler is talc, especially talc coated with the metal salts of the fatty acids mentioned above. Other preferred fillers are:
Clay, especially calcined clay. The compositions of the present invention are conveniently prepared by mixing or blending their components in a suitable device. The alkylene-alkyl acrylate copolymer and the other components described above can be mixed together by any of the techniques used in the art for mixing and compounding thermoplastics into a homogeneous mass. The calcium or magnesium oxide, carbonate, hydroxide or sulfate can be coated by known techniques prior to or during the mixing of the components together. Regarding mixing, each component is melted (fluxed) in a variety of equipment including multi-roll mills, screw mills, continuous mixers, extruders, and Banbury mixers.
can be done. When all of the solid components of the composition are available in powder form or as small particles, the composition can be prepared by first forming a mixture of the components, for example in a Banbury mixer or in a continuous extruder, and then passing this mixture through a heating mill, for example It is most conveniently prepared by kneading on a roll mill and continuing kneading until an intimate mixture of the components is obtained. In those cases where the copolymer is not available in powder form, the composition may be prepared by introducing the copolymer into a two-roll mill, kneading it around the rolls until it forms a band, and then The mixture can be prepared by adding the mixture of remaining ingredients to the mixture and continuing kneading until an intimate mixture is obtained. The roll is preferably maintained at a temperature within the range of 80 DEG to 135 DEG C. and below the decomposition temperature of the peroxide compound, if used. The composition in sheet form is removed from the mill and then reduced to a form suitable for further processing (typically dice-like pieces). The composition can then be extruded onto a wire or cable or other substrate. If the compositions of the invention are chemically curable, they can be extruded onto wire or cable or other substrates and used conventional vulcanization operations to
Vulcanization is carried out at an elevated temperature of 180°C, preferably between 200 and 230°C. The following examples are illustrative of the invention and are not intended to limit the scope of the invention in any way. Examples 1-2 Compositions of the following formulations were prepared by mixing the ingredients in a Brabender plasticord mixer preheated to a temperature of 120°C. The composition was mixed at a temperature below 135°C until homogeneous. Ethylene-ethyl acrylate copolymer with a melting index of 1.2 and a bound ethyl acrylate content of 15-17% by weight 57.0 Calcium carbonate 25.7 Flame retardant 1.5 1,2-dihydro-2,3,4-trimethylquinoline ( Antioxidant) 0.7 Di-alpha-cumyl peroxide 1.6 Ultimate Oxygen Index (ASTM D2863-70) 26.8 The flame retardant used contains 67% by weight bromine and has the formula: Ethylene (bis-tetrabromophthalimide) Ultimate Oxygen Index is a standard test used to quantitatively measure the degree of flammability. A value of 26.8 indicates that the composition of Example 1 is suitable for use as a jacket around industrial control cables and telephone wires and cables, and as insulation around electrical conductors such as copper wire. To further illustrate the beneficial properties of the compositions of the present invention, compositions were prepared as in Example 1 and tested for % ash, % halogen retained in ash, and % smoke generated. The % ash value, which is a measure of the ash content retained, is important for several reasons. The retained ash acts as thermal and electrical insulation, thus helping to maintain the integrity of the product during combustion in a fire. Retained ash also helps reduce drippings from burning products. A higher % halogen content in the ash means less halogen is released into the atmosphere. Compositions that release less halogen (measured as halogen acid) are less toxic to humans and less corrosive to equipment. Halogen content (wt%) in ash is Ouantita
-tive Organic Microanalysis (A. Steyermark), Academic Press, New York and London, 1961, pp. 316-339). The smoke generated (wt%) is reported in the Journal of Fire
and Flammability (Vol. 9, October 1978, No. 459)
466). Ash content (wt%) is determined by Plastics Technology
(March 1976, pp. 46-49). The tests described herein were conducted using plates prepared from samples of the composition. In the press under the following conditions: 5000psi pressure, 180℃ temperature and
A plate with dimensions of 3in x 8in x 0.125in was prepared with a time cycle of 15 minutes.

Table: Comparable results are obtained by varying the amounts of specific salts of calcium and magnesium and bases within the range of 20 to about 30% by weight. Example 3 A composition of the following formulation was prepared by mixing the ingredients in a Brabender Plasticord mixer as in Example 1. The compositions were mixed until homogeneous at a temperature below 135°C, molded into sample plates, and tested for ultimate oxygen index and weight percent smoke generated.

[Table] Ethylene-ethyl acrylate
polymer

【table】

TABLE It is clear that the ethylene-ethyl acrylate copolymer used according to the invention results in a composition with significantly better properties than the ethylene-vinyl acetate copolymer in Control 3.

Claims (1)

[Scope of Claims] 1. An alkylene-alkyl acrylate copolymer, 1 to 30% by weight of a halogenated flame retardant, and at least one of calcium or magnesium oxides, carbonates, hydroxides, or sulfates. 20-30% by weight of a flame retardant alkylene-alkyl acrylate copolymer composition (weight% is based on the total weight of the composition). 2. The composition according to claim 1, wherein the alkylene-alkyl acrylate copolymer is an ethylene-ethyl acrylate copolymer. 3. The composition according to claim 1, which contains magnesium or calcium carbonate. 4. The composition according to claim 1, which contains an oxide of magnesium or calcium. 5. The composition according to claim 1, which contains magnesium or calcium hydroxide. 6. The composition according to claim 1, which contains a sulfate of magnesium or calcium. 7. The composition according to claim 1, which contains an antioxidant. 8. The composition of claim 1, wherein the composition contains additional fillers. 9. A composition according to claim 8, wherein the additional filler is talc. 10. The composition of claim 8, wherein the additional filler is clay. 11. The composition of claim 8, wherein the additional filler is carbon black. 12. The composition of claim 1 containing an antioxidant, an additional filler and an organosilane. 13. A composition according to claim 1 containing an antioxidant, an additional filler and an organic titanate. 14. The composition according to claim 1, wherein the flame retardant is ethylene (bis-tetrabromophthalimide). 15. The composition of claim 1, wherein the halogenated flame retardant is present in an amount of 5 to 20% by weight. 16 Alkylene-alkyl acrylate copolymer, 1 to 30% by weight of a halogenated flame retardant, and 20 to 30% by weight of at least one of calcium or magnesium oxides, carbonates, hydroxides, or sulfates. , a crosslinkable flame-retardant alkylene-alkyl acrylate copolymer composition (wt%
is based on the total weight of the composition). 17. The composition according to claim 16, which contains a peroxide as a crosslinking agent. 18. The composition according to claim 17, wherein the peroxide is di-α-cumyl peroxide.