MXPA00010083A

MXPA00010083A - Flame-retardant polyolefin-type resin composition method for the preparation thereof, and flame-retardant cables

Info

Publication number: MXPA00010083A
Application number: MXPA/A/2000/010083A
Authority: MX
Inventors: Furukawa Haruhiko; Hatanaka Hidekatsu; Shiromoto Koji; Ueki Hiroshi; Nakanishi Koji; Morita Yoshitsugu
Original assignee: Dow Corning Toray Silicone Co Ltd
Priority date: 1999-10-13
Filing date: 2000-10-13
Publication date: 2002-07-25

Abstract

A flame-retardant polyolefin-type resin composition comprising (A) 100 weight parts polyolefin-type resin, (B) 30 to 200 weight parts powder of a hydrated metal compound, and (C) 0.01 to 50 weight parts branched organopolysiloxane with average unit formula RaSiO(4-a)/2 where each R is a selected from the group consisting of monovalent organic groups selected from the group consisting of C1 to C12 alkyl and C6 to C12 aryl and hydroxyl, wherein aryl constitutes from 50 to 100 mole%of the total monovalent organic groups and the hydroxyl content in each molecule is from 1 to 10 weight%, a is a number from 0.75 to 2.5, and the organopolysiloxane contains at least one RSiO3/2 siloxane unit in each molecule, where R is as previously described. The composition is useful as a flame-retardant coating on electrical cables.

Description

COMPOSITION OF POLYOLEFIN TYPE RESIN PIRORE REPEAT, METHOD FOR THE PREPARATION OF THE SAME AND PIROREREARNING CABLES.

BACKGROUND OF THE INVENTION This invention relates to a resin composition of the polyolefin pirorret ardante type, to a method for the preparation of the same, and to burning pirorret cables coated with the composition. More particularly, this invention relates to a resin composition of the highly conformable flame retardant polyolefin type, highly pyrethrum-containing, having excellent mechanical strength, to a method for the preparation thereof, and to fire-resistant pirorret cables having a coating of the aforementioned flame retardant polyolefin resin composition. A method used to impart fire retardance to polyolefin-type resins, for example, polyethylene resins and ethylene-vinyl acetate copolymer resins, comprises mixing polyolefin-type resin with a halogen-containing compound (chlorine is an example typical of halogen). However, polyolefin-type resin compositions loaded with such halogenated compounds, in addition to releasing large quantities of black smoke during burning, produce gases harmful to humans and corrosive to metals. The addition of the powder of a hydrated metal compound, such as aluminum hydroxide powder or magnesium hydroxide powder, to the polyolefin type resin has already been proposed in order to reference the problems described above for halogenated compounds. Unfortunately, this approach has required the addition of large quantities of the hydrated metal compound in order to impart fire retardancy to the polyolefin type resin, and this high load requirement has prevented the production of anything outside of polyolefin-type resins. ardantes with bad moldeabi 1 idades and decreased mechanical resistance. Japanese Laid-Open Patent Application Number Hei 5-339510 (339,510 / 1993) teaches the production of resin-based resin compositions of the polyolefin pi rorret type by the addition of functional branched organo loxane resin by alkoxy, phosphate ester, and resins from 'metallic hydroxide to thermoplastics such as styrenic resins and fine polyol type resins. One problem with this method is that it offers a flame retardant polyolefin-type resin composition whose fire retardancy is not completely satisfactory. In addition, because it requires the use of phosphate ester, this method, for example, may be unacceptable depending on the particular application and, within the context of elimination, for the concern of soil contamination by phosphorous compounds. The inventors achieved this invention as a result of further research aimed at solving the problems described above. In specific terms, an object of this invention is to provide a resin composition of the polyolefin pirorret type. ardante and highly adaptable. The additional objects of this invention provide a method for producing this flame retardant polyolefin-type resin composition and provide flame-retardant cables.

BRIEF DESCRIPTION OF THE INVENTION The present invention is a flame retardant polyolefin-type resin composition comprising (A) 100 parts by weight of polyolefin-type resin, (B) up to 200 parts by weight of powder of a metal compound. hydrated, and (C) 0.01 up to 50 parts by weight of branched organopolysiloxane with the average unit formula RaSlO (4-a) / 2 wherein each R is selected from the group consisting of monovalent organic groups selected from the group consists of alkyl CJ up to C? 2 and aplo and hydroxy Lo C up to C i 2, where the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups and the hydroxyl content in each molecule is from 1 to 10% in weigh, a is a number from 0.75 to 2.5, and the organopolysiloxane contains at least one siloxane unit RSi03 / 2 in each molecule, wherein R is as previously described. The invention further relates to a method for producing the resin composition of the polyolefin pirorret type. ardante and flame retardant cables that you. There is a coating of the flame retardant polyolefin-type resin composition.

DESCRIPTION OF THE INVENTION The present invention is a flame retardant polyolefin-type resin composition comprising (A) 100 parts by weight of polyolefin-type resin, (B) 30 to 200 parts by weight of powder of a hydrated metal compound, and (C) 0.01 to 50 parts by weight of branched organopolysiloxane with the average unit formula RaS IO (4-a) / 2 wherein each R is selected from the group consisting of monovalent organic groups selected from the group consisting of CJ alkyl to Ci2 and aryl and C6 to C12 hydroxyl, wherein the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups and the hydroxyl content in each molecule is from 1 to 10% by weight, a is a number from 0.75 to 2.5, and the organopolysiloxane contains at least one siloxane unit RSi03 / 2 in each molecule, wherein R is as previously described. The invention further relates to a method for producing the resin composition of the polyolefin-type pirorret: ardent and flaming pirorret cables having a coating of the flame-retardant polyolefin-type resin composition. The polyolefin-type resin (A) used in this invention as a general matter encompasses those high molecular weight compounds known as polyolefin type resins, ie the high molecular weight polymers whose main structure is derived from the hydrocarbon of the series of ethylene. Such characteristics as the specific type and things like that are not critical. The olefin type resin under consideration can be exemplified by polyethylene such as high density polyethylene, medium density polyethylene, and low density polyethylene; copolymers of ethylene with C3-α-olefin to C ?2 such as propylene, 1-butene, 1-pentene, 1-hexene, 4-metyl-1-pentene, 1-octene, and 1-decene; polypropylenes; copolymers of propylene with α-olefins from C2 to CA such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-met i 1-1 -pent ene, 1-octene, and 1-decene; ethylene-copolymer copolymer rubbers; ethylene glycol copolymer rubbers; copolymers of ethylene with vinyl monomer such as vinyl acetate, ethyl acrylate, methacrylic acid, ethyl methacrylate, maleic acid, and maleic anhydride; the copolymers produced by the modification of polyethylene or an ethylene-α-olefin copolymer with an unsaturated carboxylic acid, such as acrylic acid and maleic acid, or unsaturated carboxylic acid derivative; and mixtures of the above polyolefin-type resins. Preferred examples among these are polyethylenes, ethylene vinyl copolymers, ethylene acrylate copolymers, and maleic acid or maleic anhydride copolymers with ethylene or α-olefin. The powder of the hydrated metal compound (B) used in this invention is the essential component for imparting fire retardancy to the composition. Component (B) with a decomposition start temperature in the range of from 150 to 450 ° C is preferred because such component (B) has highly flame retardant activity. Component (B) preferably also has an average particle size in the range from 0.01 to 30 μm for good dispersibility in the polyolefin-type resins it produces. An average particle size in the range from 0.05 to 10 μm is even more preferred. Component (B) can be exemplified by the magnesium hydroxide powder, aluminum hydroxide powder, and these powders after surface treatment with a surface treatment agent such as a silane coupling agent, titanium coupling agent. or higher aliphatic acid. Magnesium hydroxide is the preferred choice among the above. Component (B) should be introduced into the present composition from 30 to 200 parts by weight per 100 parts by weight of component (A) and preferably from 50 to 150 parts by weight per 100 parts by weight of component (A) are introduced. An inability to impart a fire retardant desirable to the flame retardant polyolefin-type resin composition may occur when the addition of the component (B) falls below 30 parts by weight, although additions in excess of 200 parts by weight will cause the flame retardant polyolefin-type resin composition to have a reduced mechanical strength. The branched organopolysiloxane (C) used in the present composition is the component that characterizes this invention. The component (C) serves, in its co-use with the component (B), to improve the fire retardancy of the composition of this invention. Component (C) also serves to improve the moldability of the present composition. Component (C) is branched organopolysiloxane with the average unit formula RaSiO (4-a) / 2 containing at least one siloxane unit RSi03 / 2 in each molecule. R in RaSiO (4-a) / 2 and RSIO3 / 2 is selected from the group consisting of the monovalent organic groups selected from the group consisting of Cx alkyl to C ?2 and the aryl and hydroxyl group Ce up to Ci2 - The alkyl A to C12 encompassed by R can be exemplified by methyl, ethyl, n-propyl, isopropyl, butyl and hexyl; although the C6 aryl to Ci2 can be exemplified by phenyl, naphthyl and tolyl. The aryl should constitute from 50 to 100 mol% of the total of monovalent organic groups in component (C) and the hydroxyl content in each molecule should be from 1 to 10% by weight. The subscript a in the formula RaSiO (4-a) / 2 is a number from 0.75 to 2.5. Propyl and phenyl are preferred for the group R in the aforementioned formulas. It is essential that the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups in component (C). This value is preferably from 50 to 99 mol% and more preferably from 60 to 90 mol%. An aryl content below 50 mol% results in reduced flame retardancy for the present composition. Each molecule of component (C) must contain from 1 to 10% by weight of hydroxyl and preferably contains from 2 to 8% by weight of hydroxyl. The present composition will suffer from reduced fire retardancy at a hydroxyl content below 1% by weight or in excess of 10% by weight. Component (C) must contain at least one siloxane unit with the formula RSIO3 / 2 (unit T) in each molecule, where R is as defined above. In addition to the unit T, the component (C) may also contain siloxane units with the formula RSIO1 / 2 (unit M, R is as defined above), siloxane units with the formula R SiO2 / 2 (unit D, R is as previously defined), and silo ano units with the formula Si04 / 2 (unit Q). When these other units are present, the content of unit T is preferably at least 90 mol% and more preferably is at least 95 mol%. With respect to the presence of. unit D in component (C), unit D: the molar ratio of unit T is preferably in the range from 0: 100 to 10:90 and more preferably is from 0: 99 to 5:95. The branched organopolysiloxane is preferred with the following average molecular formula for component (C) (R13Si01 / 2) a (RX2SY? 2/2) b (1S03 / 2) c (YES4 / 2) d (H01 / 2) e in where R1 is a monovalent hydrocarbon group selected from the group consisting of C1 to C2 alkyl and C aryl? up to C12, a is zero or a positive number, b is zero or a positive number, c is a positive number, d is 0 or a positive number, and e is a positive number. The Ci to C ?2 alkyl encompassed by Ri can be exemplified by methyl, ethyl, n-propyl, isopropyl, butyl, and hexyl; although the C6 aryl to Ci2 can be exemplified by phenyl, naphthyl and tolyl. The softening point of the component (C) is preferably lower than the softening point of the polyolefin-type resin (A) and more preferably is not greater than 300 ° C. When the component (A) is a polyolefin-type resin with a relatively lower softening point, the component (C) preferably has a softening point no greater than 200 ° C and more preferably is a solid at room temperature. The average molecular weight of component (C) should be as a general matter of 300 to 500,000 and preferably 300 to 100,000 and more preferably 300 to 10,000. As used herein, the average molecular weight is the value measured by gel permeation chromatography (GPC). The content of component (C) of the present composition should be from 0.01 to 50 parts by weight and preferably from 0.1 to 30 parts by weight, in each case to 100 parts by weight of component (A). The small capacity for imparting retardation to fire is manifested in a content of component (C) below 0.01 parts by weight, although the mechanical strength is decreased in a content with excess of 50 parts by weight. The present composition comprises the components (A), (B) and (C), but can also contain to the extent that the objects of this invention do not deteriorate the various additives known to improve the properties of polyolefin-type resins. These additives can be used by inorganic fillers such as calcium carbonate, calcium silicate, potassium titanate, talc, clay, mica and silica.; oxidation inhibitors; lubricants; pigments; ultraviolet absorbers; thermal stabilizers; light resistance enhancers; dispersants; and static inhibitors. The present composition can be made simply by mixing the components (A), (B) and (C) together to provide homogeneity. In order to improve the dispersion of component (C) in component (A), in a preferred method, components (A) and (B) are mixed first with one another while heating to a temperature greater than or equal to the of softening the component (A) and then mixing the component (C) with heating. As stated above, the present resin composition can be made simply by mixing the components (A), (B) and (C) to provide homogeneity. The means for making this mixture of components can be exemplified by mixing apparatuses and composite apparatuses such as 2-roll burs, Banbury mixers and kneading mixers. Due to its excellent moldability, the present composition can be easily processed into film, sheet, splint, and pipe molds by conventional plastic molding techniques such as extrusion molding, satin molding, and injection molding. Accordingly, the obtained slurries are characterized by an excellent retardation to the flame and also by an excellent mechanical strength and therefore can be used in those applications where such applications are critical. Among such applications, the present composition is highly suitable for application to cables such as electric power cables, fiber optic cables and communication cables. The invention is explained in more detail below through the examples basic The viscosity values reported in the examples were measured at 25 ° C, although the parts in the examples denote parts by weight. The flame retardancy of the flame retardant polyolefin-type resins was evaluated by measuring the oxygen index based on JIS K 7201, "Plastics- Det erminat ion of Burning Behavior by the Oxigen Index". The mechanical strength was evaluated by measuring the tensile strength based on JIS K 7113, "Testing Method for the Tensile Properties of Plastics". The branched organopolysiloxanes used in the examples had the average molecular formulas reported below in Table 1 and the properties reported below in Table 2. The following abbreviations are used in the examples: Me for methyl, Pr for n-propyl, Ph for phenyl, D for the unit Me2Si02 / 2, T for the unit MeSi03 / 2, TPr for the unit PrSi03 / 2, and TPh for the unit PhSi03 / 2. The molecular structure of the branched organopolysiloxanes was analyzed using nuclear magnetic resonance (NMR) spectroscopy. The average molecular weight was measured by GPC. The average molecular weight is the value calculated based on the known polystyrene standards. - 1! Table 1 Table 2 Examples 1 to 4 and Comparative Examples 1 to 4 Flame-retardant polyolefin-type resin compositions were prepared to mix the components described in the proportions reported in Tables 3 and 5. The polyolefin-type resins used were high density polyethylene (Hizek 5303 from Mitsui Kagaku Kabushiki Kaisha), acrylate copolymer of etheno-et ilo (Jaylex EEA A1150 from Japan Polyolefin, abbreviated as EEA resin), and polyethylene modified with maleic anhydride. The hydrated metal compound powder used was magnesium hydroxide powder (Kisuma 5A from Kyowa Kagaku Kabushiki Kaisha). SR1 to SR4 reported in Table 1 were used as the branched organopolysiloxane. The mixing procedure is described below. The polyolefin-type resin was introduced into the mixer (a Fresa Labo-Plast from Toyo Seiki Seisakusho) and softened by heating at 180 to 220 ° C. The magnesium hydroxide powder was then introduced with the mixture. The branched organopolysiloxane was subsequently introduced with the mixture to deliver the flame retardant polyolefin type resin composition. The resulting flame retardant polyolefin resin composition was injection molded at 180 to 220 ° C. The properties (oxygen index and tensile strength) of the resulting molding were measured; these results are reported below in Tables 3 and 5.

EXAMPLE 5 A flame retardant polyolefin type resin composition was prepared by intermixing the high density polyethylene and the magnesium hydroxide powder described in Example 1 and the branched organopolysiloxane SRl to provide homogeneity in the proportions reported in Table 4. The procedure of mixing was as follows: the high density polyethylene was introduced into the mixer (a Fresa Labo-Plast from Toyo Seiki Seisakusho) and softened by heating at 180 to 220 ° C; the magnesium hydroxide powder was then introduced with the mixture; the organopolysilane branched loxane SR1 was subsequently introduced with the mixture to deliver the flame retardant polyolefin type resin composition. The resulting flame retardant polyolefin resin composition was injection molded at 180 to 220 ° C. The oxygen index of the resulting molding was measured and the results are reported below in Table 4.

Example 6 An energy cable was manufactured by coating an electric wire with the flame retardant polyolefin-type resin composition in Example 1. The wire (conductor cross-section = 8 mm2) comprised a central wire covered with degraded polyethylene insulation (thickness coating = 1 mm) . The power cable was manufactured by coating this wire with a thickness of 1.8 mm of the flame retardant polyolefin type resin composition of Example 1. An excellent appearance was presented by the power cable coated with the flame retardant polyolefin-type resin composition. The fire retardancy of this power cable met the requirements of the test when evaluated by flame testing VW-1 of UL Standard 758. Comparative Example 5 The energy cable coated with a flame retardant polyolefin type resin composition was manufactured according to the procedures of Example 6, but in this case using the flame retardant polyolefin-type resin composition prepared in Comparative Example 1 more than the polyolefin-type resin composition that was used in Example 6. The resulting power cable had a good appearance, but did not meet the test requirements when subsequently evaluated by flame test VW-1 of UL Standard 758.

Table 3 Table 4 Table 5 polyolefin-type resin composition, a method for producing the same, and burning pirorret cables.

Claims

CLAIMS Having described the invention as an antecedent, the content of the following claims is claimed as property: 1. A flame retardant polyolefin-type resin composition characterized in that it comprises (A) 100 parts by weight of polyolefin-type resin, (B) 30 up to 200 parts by weight of powder of a hydrated metal compound, and (C) 0.01 to 50 parts by weight of branched organopolysiloxane with the average unit formula RaSiO, 4-a) / 2 wherein each R is selected from the group that consists of monovalent organic groups selected from the group consisting of Cx to C12 alkyl and C6 to C12 aryl and hydroxyl, wherein the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups and the hydroxyl content in each molecule is from 1 to 10% by weight, a is a number from 0.75 to 2.5, and the organopolysiloxane contains at least one siloxane unit RSi03 2 in each molecule, where e R is as previously described. 2. The flame-retardant polyolefin-type resin composition according to claim 1, characterized in that the component (C) is organopolysiloxane branched with the average unit formula (R3SiO? / 2) a (R2SÍ? 2/2) ARSÍ? 3/2) ASi04 / 2) d (H01 / 2) e wherein R is a monovalent organic group selected from the group consisting of C 1 to C 2 alkyl and C 6 to C 2 aryl, the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups, the hydroxyl content in each molecule is from 1 to 10% by weight, a is zero or a positive number, b is zero or a positive number, c is a positive number, d is 0 or a positive number, and e is a positive number. 3. The flame-retardant polyolefin-type resin composition according to claim 1, characterized in that the monovalent organic groups of the component (C) are selected from the group consisting of propyl and aryl. 4. The flame retardant polyolefin type resin composition according to claim 1, characterized in that the component (C) has an average molecular weight of from 300 to 10,000. The flame retardant polyolefin type resin composition according to claim 1, characterized in that the component (C) is solid at room temperature. The flame retardant polyolefin type resin composition according to claim 1, characterized in that the component (B) is selected from the group consisting of magnesium hydroxide powder and aluminum hydroxide powder. The flame-retardant polyolefin-type resin composition according to claim 1, characterized in that the component (A) is selected from the group consisting of polyethylenes, copolymers of ethyl acetate and vinyol, acrylate copolymers of et i leno -et i lo, and copolymers of maleic acid or maleic anhydride with ethylene or α-olefin. The flame retardant polyolefin type resin composition according to claim 1, characterized in that the component (B) has an average particle size in the range from 0.05 to 10 μm. 9. The flame retardant polyolefin type resin composition according to claim 1, characterized in that the aryl constitutes 60 to 90 mol% of the total of monovalent organic groups in the component (C). 10. The flame-retardant polyolefin-type resin composition according to claim 1, characterized in that each molecule of the component (C) contains from 2 to 8% by weight of hydroxyl. 11. The flame retardant polyolefin-type resin composition according to claim 1, characterized in that it comprises from 0.1 to 30 parts by weight of component (C) per 100 parts by weight of component (A). 12. A manufacturing article having therein a pyro-retardant polyolefin-type resin composition characterized in that it comprises (A) 100 parts by weight of polyolefin-type resin, (B) up to 200 parts by weight of powder of a compound of hydrated metal, and (C) 0.01 to 50 parts by weight of branched organopolysiloxane with the average unit formula RaSÍO (4-a) / 2 wherein each R is selected from the group consisting of monovalent organic groups selected from the group consisting of in Ci alkyl to CX2 and aryl and C6 to C12 hydroxyl, wherein the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups and the hydroxyl content in each molecule is from 1 to 10% by weight since it is a number from 0.75 to 2.5, and the organopolysiloxane contains at least one RSIO3 / 2 siloxane unit in each molecule, wherein R is as previously described. 13. The article of manufacture according to claim 12, characterized in that the component (C) is organopolysiloxane branched with the average molecular formula (R3Si01 2) a (R2Si02 / 2) b (RSi? 3/2) c (Si04 / 2) ci (HO? 2) e wherein R is a monovalent organic group selected from the group consisting of Cx alkyl to Ci and C6 aryl to C? 2, the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups , the hydroxyl content in each molecule is from 1 to 10% by weight, a is zero or a positive number, b is zero or a positive number, c is a positive number, d is 0 or a positive number, and e is a positive number 14. A flame-retardant cable having applied thereon a flame-retardant polyolefin-type resin composition characterized in that it comprises (A) 100 parts by weight of polyolefin-type resin, (B) up to 200 parts by weight of a powder of a compound of hydrated metal, and (C) 0.01 to 50 parts by weight of branched organopolysiloxane with the average unit formula RaSÍO (4-a) / 2 wherein each R is selected from the group consisting of monovalent organic groups selected from the group which consists of alkyl A to C 2 and aryl and hydroxy to C 12, wherein the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups and the hydroxyl content in each molecule is from 1 to 10% in weight is already a number from 0.75 to 2.5, and the organopolysiloxane contains at least one RSIO3 / 2 siloxane unit in each molecule, wherein R is as previously described. 15. The flame retardant cable according to claim 14, characterized in that the component (C) is organopolysiloxane branched with the average molecular formula (R3SÍO? / 2) a (R2SÍ? 2/2) b (RSÍ03 / 2) c (YES? 4/2 A (HOl / 2) e wherein R is a monovalent organic group selected from the group consisting of C 1 to C 12 alkyl and C to C 12 aryl, the aryl constitutes from 50 to 100 mol% of the total of monovalent organic groups, the hydroxyl content in each molecule is from 1 to 10% by weight, a is zero or a positive number, b is zero or a positive number, c is a positive number, d is 0 or a positive number , and is a positive number. SUMMARY

A flame retardant polyolefin-type resin composition comprising (A) 100 parts by weight of polyolefin-type resin, (B) 30 to 200 parts by weight of powder of a hydrated metal compound, and (C) 0.01 to 50 parts by weight. weight of branched organopolysiloxane with the average unit formula RaSlO (4 _a) / 2 wherein each R is selected from the group consisting of monovalent organic groups selected from the group consisting of Ci to CX2 alkyl and aryl and C6 hydroxy to C? 2, wherein the aplo constitutes from 50 to 100 mol% of the total of monovalent organic groups and the hydroxyl content in each molecule is from 1 to 10% by weight, a is a number from 0.75 to
2.5, and the organopolysiloxane contains at least one RSi03 / 2 siloxane unit in each molecule, where R is as previously described. The composition is useful as a flame retardant coating on electric cables