CA1167991A - Polymeric compositions - Google Patents
Polymeric compositionsInfo
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- CA1167991A CA1167991A CA000363754A CA363754A CA1167991A CA 1167991 A CA1167991 A CA 1167991A CA 000363754 A CA000363754 A CA 000363754A CA 363754 A CA363754 A CA 363754A CA 1167991 A CA1167991 A CA 1167991A
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- Prior art keywords
- hydrated alumina
- antimony
- water
- compound
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Abstract
ABSTRACT
A water stabilised polymeric composition incorporating a hydrated alumina filler as one component, an effective amount of an antimony V compound as another component, and in which one or each of the components is/are coated with a reagent which can chemically react with, or physically bond to, the surface of the other component. The compositions have a reduced tendency to absorb water and specific compositions find application as electrical insulation and in the production of dimensionally recoverable articles. Coating reagents include acids, reactive functional acid derivatives and complexing or chelating agents.
A water stabilised polymeric composition incorporating a hydrated alumina filler as one component, an effective amount of an antimony V compound as another component, and in which one or each of the components is/are coated with a reagent which can chemically react with, or physically bond to, the surface of the other component. The compositions have a reduced tendency to absorb water and specific compositions find application as electrical insulation and in the production of dimensionally recoverable articles. Coating reagents include acids, reactive functional acid derivatives and complexing or chelating agents.
Description
~ 1~79'~
The present invention concerns polymeric compositions and more specifically such compos~tions which contain a particulate filler or fillers and is related to co-pending Canadian Patent Application Serial No. 363,7~2 inventor Richard Stuart Skipper.
Polymeric compositions incorporating hydrated alumina fillers, especially of the formula A12O3. x H20 wherei~ x is 0.5 to 3, e.g. to impart flame retardant properties or to enhance the anti-tracking properties in electrical applications, frequently exhibit a tendency to absorb water particularly when the composition comprises a polar polymer.
This tendency to absorb ~ater is often directly or indirectly attributable to the particulate filler, i.e. to the hygroscopic nature of the filler per se or of the filler after incorporation into the polymeric composition. In the latter respect, it has been found that hydrated aluminas when incorpoated into certain polymeric composit~ons can undergo, at least to a limited extent, a chemical or physical transformation yielding a chemical species substantially more hygroscopic than the incorporated filler per se.
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The present invention concerns polymeric compositions and more specifically such compos~tions which contain a particulate filler or fillers and is related to co-pending Canadian Patent Application Serial No. 363,7~2 inventor Richard Stuart Skipper.
Polymeric compositions incorporating hydrated alumina fillers, especially of the formula A12O3. x H20 wherei~ x is 0.5 to 3, e.g. to impart flame retardant properties or to enhance the anti-tracking properties in electrical applications, frequently exhibit a tendency to absorb water particularly when the composition comprises a polar polymer.
This tendency to absorb ~ater is often directly or indirectly attributable to the particulate filler, i.e. to the hygroscopic nature of the filler per se or of the filler after incorporation into the polymeric composition. In the latter respect, it has been found that hydrated aluminas when incorpoated into certain polymeric composit~ons can undergo, at least to a limited extent, a chemical or physical transformation yielding a chemical species substantially more hygroscopic than the incorporated filler per se.
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- 2 RK109/128 The presence of such chemical species in a filled polymeric system may result in a very high water pick-up when exposed to wet environments 9 especially hot wet environments.
The tendency of polymerio compositions to absorb water may render the use thereof in certain applications unsuitable~
particularly in electrical insulation applications and especially flame retarded systems wherein reliance is placed on hydrated alumina fillers to provide flame retardancy.
The present invention is concerned with reducing or elimin-ating the tendency of hydrated alumina filled polymeric compositions to absorb water, hereinafter referred to as "water stabili~ation" and the expression "water stabiliser"
is to be construed accordingly.
A first aspect of the present invention provides a water stabilised polymeric compositionj inoorporating a hydrated alumina filler as cne component, an effective amount of an antimony V compound as another component, in which one or each of the components is/aré coated with a reagent which can chemlcally react with, or physically bond to, the surface of the other component.
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A aecond aspect of the present invention provides water stabilised hydrated alumina whioh includes an effective . ~ .
~ - - amount ~of an antimony V compound and in which one or each . . . ~ .... .. .
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--' 1167991 of the hydrated alumina and the antimony V compound components is/are coated with a reagent which can chemically react wlth, or physically bond to, the surface of the other component.
A third aspect of the present invention provides a process for producing a water stabilized hydrated alumina in which the hydrated alumina is treated with an effective amount of an antimony V compound and wherein one or each of the hydrated alumina and the antimony V compound components is/are coated with a reagent which can chemically react wi-th or physically bond to the surface of the other component.
A fourth aspect of the present invention provides a water stabilized dimensionally recoverahle, and especially heat-recoverable, article comprising a water stabilized polymeric composition incorporating a hydrated alumina filler as one component and an effective amount of an antimony V compound as another component, in which one or each of the components is/are coated with an acid, a reactive acid derivative, or a complexing or chelating a~ent.
A fifth aspect of the present invention provides electrical equipment, for example a wire or cable, or a high voltage in ulator, incorporating as electrical insulation a water stabilized polymeric composition incorporating a hydrated alumina filler as one component and an effective amoun-t of an antimony V compound as another component, in which one or each of the components is/are coated wi-th an acid, a reactive acid derivative, or a complexing or chelating agent.
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- . : . : , . ' 67g~1 The particulate fillers that may be employed in the composi-tions of the present invention are those which have a tendency to absorb water at least after incorporation into the composition. Particularly important classes of fillers include hydrated aluminas used as inorganic flame retardants and electrical anti-tracking agents, especially hal~gen-~free such fillers. Preferred fillers are hydrated aluminas of the formula Al203. x H20 wherein x is 0.5 to 3, for example alumina mono-hydrates e.g. Al203.H20, but especially alumina trihydrate Al203.3~20. In this specification the term hydrated alumina is also intended to include materials which are known as aluminium hydroxides e.g. Al(OH)3 and aluminium oxyhydroxides e.g. AlO.OH. Other suitable hydra-ted alumina fillers include ammonium and sodium dawsonite.
Mixtures of hydrated alumina fillers may be used if desired.
The hydrated alumina filler used iG preferably selected from those having a surface area of at least 0.1m2/g7 up to 300mm2/g and most preferably having a surface area of from 0.1m2/g to 100m2/g, particularly 2 to 40m2/g, and especially 4 to 16m2/g, as measured by the B.E.T. methGd~ Outstanding improvements in the electrical properties of filled polymer compositions containing high surface area alumina trihydrate f illers may be achieved~using the present invention.
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The amount of filler incorporated in the compositions of the invent:ion will naturally depend inter alia on the nature ~: .
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thereof although in general, amounts in the range 5 to 80%, more preferably 20 to 70~, especially 30 to 70%, eOg. 40 to 70% based on the weight of the composition, are preferred.
Whilst we believe that insolubilisation of residual sodium in the filler plays a role in water stabilisation by anti-mony V compounds, the complete mechanism of water stabili-sation is not fully understood and will vary depending on the nature of the insolubilising agent. It is conjectured that in addition to forming a water insoluble compound with any available sodium present, the antimony V compound may also function as a water stabiliser by forming a water barrier around the filler particles thereby inhibiting water access to any hygroscopic moieties in the hydrated alumina even when the antimony V compound is not pre-coated onto the filler. Furthermore, and depending on the nature of the filler and antimony V compound, we believe, that such water :
barrier may be the result of interaction between the antimony V compound and the surface of the filler particles.
Although not essential, it is preferred that the level of sodium impurity in the hydrated alumina should be reduced to :~:
a minimum. This may be~ achieved by pre-treatment, for ` example, washing with~water~or an aqueous medium particu-`~ larly ~aqueous inorganic or organic acids, e.g. to a total sodium~level less than 1000 ppm, more pre~erably less than , ; 600 ppm of sodium mea ured as Na2O, based on the weight of ` ~ the hydrated alumina.
.. ,, ..~ .., 799 i - `6 - RK109/128 , Reduction of the sodium impurity level may also be achieved by pre-treatment of the filler with a sodium complexing or chelating agent such as particularly zinc or magnesium uranyl acetate, but also uranic acid, molybdic acid, orthophosphoric acid, hypophosphorous acid, dodecamolybdo-phosphoric acid and polydentate ligands such as polyketo-nates. Such treatment is normally followed by washing of the filler to remove any water soluble compounds thus formed.
Many conventional polymer processing methods involve milling, internal mixing e.g. in a Banbury mixer, or other treatment stages likely to cause some break-up of the filler particles thereby exposing sodium ions prev1ously trapped within the crystal latticP. It will be appreciated therefore that for many purposes merely reducing the soluble sodium content of the filler prior; to bl~ending with the polymer is not suffi-cient to water stabilise the filled polymer system.
~he antimony V compound may be incorporated by distribution thereof throughout the composition or alternatively the particulate filler may be treated by coating therewith as appropriate.
~owever,~it~has been found that greatly improved results are , obtained if the hydrated alumina, an efféct~ve amount of the antimony V compound, anù the polymer, are processed to~ether, fo~ example on a mill or in an internal mixer, for . : . ~ .
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- 7 - RK109~128 an extended period of time. Such processing i~ preferably carried out f~r at least 5 minutes, and preferably from 10 to 60 minutes. Alternatively, the hy~rated alumina may be treated with the antimony V compound prior to blending with the polymer9 Suitable antimony V compounds include, for example the hydrated forms of antimony V oxide, especlally the monohydrate Sb2O5 H2O, antimony alkogides, for example antimony V pentamethoxide, and antimony pentahalides, for example antimony pentachloride. The treatment step may require to be followed by a waghing treatment with an aqueous or organic solvent depending upon the antimony V
compound used but at least in the case of the hydrated antimony V oxides this is not essential.
Whatever the mechanism of the water stabilisation ~by the antimony~V compound, it has been found in accordance with this invention that further improved results may be obtai-ned when the hydrated alumina or the antimony V compound, or both, is/are coated with a reagent which can chemically react with or physically bond to the surface of the other.
Thus`where the hydrated alumina is coated, the reagent is one that can chemically react with or physically bond to the surface of the antimony V compound, and vice versa. It is postulated~that the functio~ of the coating reagent is in~some ~way ~to~lmprove the interaction of the an~imony V
compound with~the surface of the hydrated alumina, thereby :
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assisting in the insolubilisation of residual sodium or water barrier ~ormation as previously discussed. Thus the coating reagent should be one that i3 capable of forming a covalent bond, a complex, or at least providing attractive ~orces, for example Van der Waals forces, between the antimony V compound and the surface of the hydrated alumina.
As examples of reagents which may be employed to coat the surface o~ the hydrated alumina and/or the antimony V
compound there may be mentioned acids,both organic and inorganic, and reactive functional acid derivatives, e.g.
esters, acid halides and anhydrides, and complexing or chelating~ agents including polydentate ligands such as ~-polyketonates and Schif~ base (imine3 derivatives thereof.
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Examples of organic acids incIude mono ~ or polybasic , substituted or unsubstituted carboxylic, thiocarboxylic or sulphonic acids such as monobasic C2-C20 pre~erably C3-C20 acids, e.g. acrylic, acetic, n-propionic, n-butanoic, , n-hexanoic,~ n-octanoic,~lauric and stearic acids, aromatic acids, e.g. benaoic acid and polybasic C2-C20 acids, e.g.
oxalic,~maleic,~fumaric, malonic, succinic and itaconic - .
acids and derivatives such as the anhydrides and monoesters, especlally mono-alkyl or a-alkenyl esters, thereof.
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Examples of inorganic acids include dilute mineral acids such as hydrochloric acid as well as phosphoric acid, molybdic acid, hypophosphorous acid and telluric acid.
Suitable polyketonates and Schiff base derivatives include those derived from polyketones of formulae R-CO-CH2 ( CO-CH2 ~m-CO-R
Where R and R1 are the same or different and can ~ be alkylp alkenyI, aryl or alkaryl group~
and m = O or an integer.
Examples of such compounds include acetyl acetonep allyl a~eto-acetonate, di-acetyl acetone, benzoyl acetyl acetone, :
dibenzoyl acetone,~ and benzoyl allyl aceto-acetonate. A
suitabIe Schiff base~derivative is:
--~ H3coc~2cocH:c(cH3)N8cH2]
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Furthermore, by appropriate choice of coating reagent, the treatment may addi~ionally serve to reinforce the composition, for example by employing u~nsaturated reagents, particularly unsaturated carboxylic or thiocarboxylic acids or functional derivatives thereof, such as acrylic, meth-acrylic, vinylacetic, allylacetic, fumaric, maleic or itaconic acids, or unsaturated esters, e.g. allyl es~ers of polybasic, particularly dibasic, acids, e.g. the rnono-allyl ester of malonic, maleic or succinic acids, whereby the unsaturated function enables grafting of the reagents to the polymeric matrix of the composition.
Under certain circumstances, various desirable properties may be opt~imised by the use- of a plurality of pre-coating reagents. Thus a combination of acryIic and stearic acids : ~ :
permi~s a satisfactory balance of physical and water stabilisation propèrties~
The amount of coating reagent(s) employed preferably lies in the range 0~1 to 15 weight per cent, more prefer-ably-1 to 10 weight~ per cent based on the weight of the fiIler~ ~
, Of the posslble antimony V compounds, including antimony V
comple~xes~, which may be employed in the compositions of the present ~invention~particularly preferred are the hydrated .
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~ RK109/128 forms of antimony V oxide, especially the monohydrate, i~e.
Sb2O5.H2O, and precursors thereof. Such precursors include compounds which during processing or by other chemical or physical treatment may be converted into a hydrated antimony V oxide. However good results may also be obtained using antimony V alkoxides, for example antimony V pentamé~hoxide.
The antimony V compound is present in an amount effective to improve the water stabi1ity of the composition, said amount being preferably in the range 0:1 to 60 weight per cent based on the composition, more preferably 0.1 to 25 weight per cent, although for water stabilisation purposes only, it has been found that amounts in the range 0.1 to 10 weight per cent e.g. 0.5 to lO weight per cent are quite satis-factory. However, it has also surprisingly been found that whilst lower amounts have~ no substantia1 positive effe~t~on flame retardancy of the composition and indeed, in some instances a depression of flame retardance is observed, in higher amounts, e.g. above 5 weight per cent, preferably from 10 to 25 weight per cent, especially 10 to 15 weigh~
per cent based on the composition, a substantial increase in .
flamè retardance is observed a~ elevated temperatures, i.e.
as measured by the British Ministry of Defence specification NE5 7l5~ base~d~ on ASTM-D-2863) whilst still providing satlsfactory water ~tabilisation.
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Polymeric compositions wherein the water stabilisers have ~een found to exhibit notable efficacy in reducing water absorption include non-cross-linked and cross--linked thermoplastic or elastc~eric substituted or unsubstituted pol~aIkenes or alkene oopolymers, such as alkene/aIkene copolymers, vinyl ester hcmo - or co-polymers and (meth)acrylate homo - or copolymers.
The term "copolymer" as used herein is employed in a broad sense to mean any polymer containing at least 2 different monomeric species and includes ter-polymers and the like.
Unsubstituted polyalkenes and aIkene copolymers of interest include polyethylenes and aIkene/alkene ~opoly~iers such as ethylene/alkene copolym~rs, especially those disclosed in UK Patent Application No. 2019412A and Canadian Patent No. 873,828 and elastomers such as EPDM (ethylene/propylene/diene manomer) and SBR (styrene/
butadiene rubker).
The vinyl ester homo - or copolymers of int rest are those derived from vinyl ester moncmers ot forTLla I, .~.
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R2 O - C - R ~
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o wherein R1, R2 and R3 are each, independently hydrogen or a substituted or unsubstituted hydrocarbon group having up to 20 carbon atoms, e~g.~ C1 -- C6 alkyl, and R4 is a subatituted or unsubstituted hydro-carbon group having up to 2:0 carbo~ atoms, : :
which may optlonally include one or more ~ hetero atoms,~ :especlally where R~ R2 and R3 are each~1ndepen-dently h~drogen or C:1 - C6 alkyl,: and~
one~ of~R1, R2 and R3 may~a}so s1gnify ~ -~
phenyl: or benzyl, and R4 is an alkyl, : ~ :
alkenyl, alkoxya1kyl~or alkoxy-alkenyl, :aryl or aralkyl group having up to 20 carbon atoms e.g. phenyl, naphthyl or benzyl, or C1~- C4, alkyl - or alkoxy- ~ ;
.phenyl::~or~ben~zyl, and particularly when :
R4~ s~C1~-;Cj5 alk~l, phenyl or - : , - i '' ~ ' , .
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- 14 - RK109/~28 .
Examples of specific vinyl ester monomers useful in the polymers of in~erest are vinyl acetate, vinyl propionate, vinyl hexanoate, vinyl octanoate, vin~l versatate, vinyl stearate, vinyl laurate, vinyl methoxy-acetate, vinyl trimethylacetate, vinyl isobutyrate, vinyl tert. pentoate, vinyl lactate, vinyl caprylate, vinyl pelargonaté, vinyl myristate, vinyl oleater vinyl linoleate, vinyl benzoate, vinyl (C1 - C~) alkoxy benzoate, vinyl octylphthalate, vinyl ~-phenyl butyrate, vinyl ~-naphthoate, vinyl ethyl phthalate and vinyl phenyl aeetate.
Vinyl ester copolymers of interest include mixed vinyl ester copolymers e.g. copolymers of vinyl acetate wi~h higher vinyl esters, e.g. vinyl laurate as well as copolymers wlth comonomers other than vinyl esters. Other such comonomers include unsaturated hyd~rocarbons such as ole~ins e.g.
ethylene, propylene, particularly C4~ - C12 ~-unsaturated olefins, e.g. but-l-ene, hex-l-ene and oct-l-ene, styrene and unsubstltuted or substituted esters, e.g. Cl - C12 (meth) acrylates and other vinyl monomers, e.g. vinyl chloride.
When copolymers wlth comonomers other than vinyl esters are employed, then preferably the vinyl ester monomer~s) is present in at~least 5;mole %, preferably at least 10 mole %, e.y. 20 - 95 mole %, more pre~erably at least 30 mole ~, .
~e.g. 40~- 95 mole %.
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e79~1 - 15 -' RKlO9/128 The (meth) acrylate homo - or copolymers of interest are those derived from (meth) acrylate monomers of formula I I , - CH2 = C I I
\C - O - R6 n O
wherein R5 is H or CH3 and R6 is a substituted or unsubstituted - hydrocarbon group having up~to 20 carbon atoms~, which may optionaIl~ include one or.more-hetero atoms, preferably an ..
alkyl, alkenyl~, alkoxyalkyl or alkoxy~
alkenyl.~aryl o~:aralkyl group having up to 20 carbon atoms, e.g. phenyl, naphthyl or benzyl, and particularly ~ C1 - C15~ alk~yl, phe:nyl or benzyl.
Preferred homo~ polymers~lnclude polyethyl acrylate, poly- ~ ~ ;
butyl:~:acrylate. :~Partlcularly prefe;rred (meth)acrylate copolymers~are:ethylene/ethyl acrylate (18 weight per cent), ~ethylene/ethyl~methacrylàte (20 weight per cent) and ter-polymers:~of~ethylène, methyl acrylate and a cure-site .
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carboxyl-containing mono~er such as the terpolymer c~om~rcially available from D~Pont under the trade name "Vamacl'* and analogous polymers described in UK
Patent No. 1,548,232. Other copolymers suitable for use in the present inve~tion include those derived from any of the above ~entioned monomers and a cure site mono~er such as 2-chloroeth~l vinyl ether or 2-chloroethyl acrylate.
Okher polymers of interest which }nay be employed in the ccmpositions of the invention include epoxy resins especially cycloaliphatic epoxy resins such as those employed for high voltage insulation applications, e.g. Araldite* CY175 and Bakelite* FRC 4221 especially when cured with cycloaliphatic acid anhydrides e.g. hexa-hydr~ phthallic anhydride, unsaturated polye~ters especially glass filled polyesters, and polyamides especially aliphatic polyamides such as nylons.
Furthermore, such polymers may be e~lployed as a blend system containing other polymers. Preferred polymer blends are those compris~ng vmyl ester homo - or ccpolymers, (meth)acrylate homo - or copolymers, and/or substituted or unsub-stituted polyalkenes or alkene copolymers. Blend polymers of interest are those which are preferably ccmpatible, either alone or in assod ation with compatabiliS-ing agents, with the aforedescribed polymers and which do not render the composi-tions unsuitable for the purpose for which they are intended. Such blends may include blends of two or more of the aforedescribed polymers or blends with other polymers including thermoplastic and elastomeric polymers, examples of which are polyesters and polyethers including segmented polyether ester copolymers of the type available from DuPont under the trade name Hytrel and described in Polymer Engineering and Scienoe 14 volume 12, 848-852 1974 'ISegmented Polyether Ester copolymers - a new generation of high performanoe elastomers", silicone resins and elastomers and acrylic elastDmers. Some preferred polymer blends are des-cribed and claLmed in UK Patent No. 1,284,082 and in Genman Offenlegenschrift No.
2815520.
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In the case of vmyl ester or (meth)acrylate polymers, when blends are employed s~lch poly~ers are preferably present in the blend in at least 20 weight per cent, e.g. 30 - 99 weight per oent, more pre~erably at least 40 wei~ht Fer cent, e.g.
50 - 99 weight per cent.
me polymer composition may also contain other additiv~s such as organic halogen containing or morganic flame retardants, or organo-phosphorous ccmpound5, anti~
-tracking agents, high voltage erosion suppressants, stahilisers, e.g.
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antioxidants and ultra-violet stabilisers, illers, pig-ments, colourants and the like. In general it is pre~erred that the composition contain little or ~o halogen, e.g. less than 15 weight per cent based on the composition, more preferably less than 10 weight per cent, especially less than 5 weight per cent of halogen atoms.
~or most purposes, it is preferred that the compositions o~
the invention are substantially cross-linked.
The degree of cross-linking of the compositions may be èxpressed in terms of the gel content (ANSI/ASTM D2765-68) of the cross-linked polymeric composi~ion, i.e. excluding non-polymeric additives that may be present. Preferably the ge~l content of the cross-linked composition is at least 10%~
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more preferably at least 2~0%~ e.g. at least 30~ more preferably at least 40~
The compositions of the invention are produced in conven-tional manner,~for example by blending together the compo-nents of the composition in a Banbury mixer.
They may then be processed~into shaped articles, for example by~extrusion or moulding~ and wh0n desired simultaneously or ~subsequently cross-linked. Shaped articles so produced also form part of the present inventlon.
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When desired the polymeric components of the ccmposition may be cross-linked either by the incorporation of a cross-linking agent or by exposure to high energy radiation. Examples of suitable cross-linking agents are free radical initiators such as peroxides for exa~,ple, dicumyl peroxide, 2,5-bis-(t-butyl-peroxy)-2,5-dimethylhexane, 2,5-bis-(_-butyl~peroxy)-2, 5~dimethylhexhyne-3, and ~,~-bis(_-butyl-peroxy)-di-iso propylbenæene. O*her examples of appropriate cross-linking agents are disclosed in C.S. Sheppard & V.R. Kamath Polymer Engineering & Science 19 No. 9 597-606, 1979 "The Selection and Uæ of Free Radical Initiators". In a typical chemically cross-linked ccmposition there will be about 0.5 to 5 wcight per oent of peroxide based on the weight of the poly-meric composition. me cross-linking agent may be employed alone or in associa-tion with a co-curing agent such as a poly-functional ~inyl or allyl cGmpound, e.g. triallyl cyanurate, triallyl isocyanurate or pentaerythritol tetra meth-acrylate.
Radiation cross-linking may be effected by exposure to high energy irradiation such as an electron beam or y-rays. Radiation dosa~es in the range 2 to 80 ~rads, preferably 2 to 50 Mrads, e.g. 2 to 20 Mrads and particularly 4 to 15 Mrads are in general apprcpriate.
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For the purposes of promoting cross-linXing during irradia-tion pre~erably from 0.2 to 5 weight per cent of a prorad such as a poly-functional vinyl or ~llyl compound, for example, triallyl cyanurate, triallyl isocyanurate or pentaery~hritol tetramethacrylate are incorporated into the composition prior to irradiation.
The compositions of the invention are particularly suitable for electrical insulation use, e.g. where flammability requirements are stringent or high voltage anti-tracking properties are desired and water absorption highly undesir-able, for example wire and cable applications in confined areas such as aircraft, ships, mines or railways including metro systems, or termination and splicing of high voltage cables or as insulation in non-track1ng high voltage appli-cations, e.g~ insulators, bushings and bus bar systems.
The production of electrical insulation material may be achieved by conventional techniques, for example by extru-sion of the non-cross-linked composition, as an insulator, : :
onto the electrical equipment such as a copper conductor as a~primary insulation,- or a~ bundle of primary insulated copper wires as~ a; cable j~acket and preferably, simultan-eously or~subsequently cross-linking the applied insulation.
As aforedescribed, the~ compositions of the present inven~ion are also particularly suitable in cros~-linked form for the .. .: ~
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production of dimensionally recoverable articles, that is to say, articles, the dimensional configuration of which may be made substantially to change when sub~ected to an appro-priate treatment. of particular interest are heat-recover-able articlesl the dimensional configuration of whlch may be made substanti~lly to change when subjected to heat treatment.
Heat-recoverable articles may be produced by deforming a dimensionally heat-stable coniguration of the article to a dimensionally heat-unstable configuration, the article assuming or tending to assume the heat-stable configuration thereof on the application of heat alone. As is made clear in US Patent No. 2,027,962, however, the original dimen-sionally heat-stable configuration may be a transient form in a continuous process in which, for example, an extruded tube is expanded, whilst hot,- to a dimensionall~ heat-unstab?e form~
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Alternatively a preformed dimensionally heat-stable article may be deformed to a dimensionally heat-unstable orm in a separate stage. In the production of dimensionally recover-able articles, the-~composition may be cross-linked at any stage in the-production process that will acomplish the desired dimensional recoverability. One mannér of producing a heat~recoverable article comprises shaping the pre~cross-.
: ~llnked~ compositlon lnto the desired heat-stable form, `~ subsequently cross-linking the composition, heating the . , : ~ ~ -- . ' ' " ': . ~ : , , ' '' a~7s~
article to a temperature above the crystalline melting point or~ for amorphous materials ~he softening point, as the case may be, of the polymer, deforming the~article and cooling the article whilst in the deformed state so that the de-formed state of the article is retained. In use, since the deformed state of the article is heat-unstable, application of heat will cause the article to assume its original heat-stable shape. Such dimensionally recoverable articles may be employed as Elame retarded and/or ~nti-tracking sleeves for covering and/or sealin~ splices and terminations in electrlcal conductors, for environmentally sealing damaged regions or joints in utility supply systems, e.g.
gas or water- pipes, district heating systems, ventilation and heatinq ducts and conduits or pipes carrying domestic or industrial effluen~.
Adhesives and seal'ants in accordance with the fourth aspect of the invention are particularly those which find use in electrical applications for example iD harnesslng systems, and especially ln high voltage applications wherein anti-tracking'fillers such as 'h~ydrated alumina are employedO
Preferred sealants include elastomer/tackifier formulations . ~ , , .
such as butyl rubber/polyisobutylene or epichlorohydrin ~: , ^ :
rubber/polyketone~resin compositions. Preferred adhesives include epoxy, especially cyclo aliphatic epoxy and silicone based adhesives.~
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'~ ' . ' ' .
1 ~79g l Panelling and cladding materials in accordance with the fifth aspect of the inven-tion include materials such as those disclosed and claimed in UK Patent Applica-tions Nos. 2035333A and 2044777A, as well as epoxy m~ulding cc~positions and unsaturated polyesters particularly when glass-fibre rein~orced. Such materials may be processed into final shape by thermoforming, e.g. by vacuum forming, mould-ing or laying-up techniques.
me invention is illustrated by the accompanying examples wherein parts c~nd per-centages are by weight and te~peratures are expressed in &.
I ~ g ~ ~
- 24 - RK10g/128 The compositions set out in Table 1 bel~w were compounded on a 2 roll laboratory mill heated to a temperature of 120 -140, and moulded at 170 into test plaques of 2mm thickness Each composition incorporated 40% ~compositions H and I) or 60% (compositions A to G) commercial fire retardant grade Al2O3. 3H2O which had been pre-coated with the reagents disclosed in Table 1 and the indicated amount of commercial grade Sb2O5. H2O. The test plaques were then irradiated with a 5.8 MeV electron beam to a total dosage of 12 Mrads.
The composition of each formulation employed is set out in Table 1 below which shows the number of parts of: each cons~ituent.
- : ~ : : :.
- : ~
, `: . ~
. . , ' '' ' ~
, ~ :
~' . "~ ' . ' ' "''' " ' ' ' ', ,' ":
~, .~ 111679~
- RK109/l28 TABLE l COMPOSITION POLYMER FILLER COATING sb20s. HzO
(Wt %~of filler) (Wt % of filler~
A 60% vinyl acetate/40% 5% acrylic ac;d 5%
ethylene copolymer B Il . 5% acrylic acid lO%
C '' 1.3% oleic acld 5%
D " 2% stearic acid 5%
E " 66% of filler coated lO%
~ith 2% of stearic.
acid and balance coated with 3% of acrylic acid F " lO% stearic anhydride 2%
G " 5~ citric acid 2%:
H ~ SCLAIR 8105 (Trade Name~- 5%:acryl~ic: acid 5%
L.inear low:density poly~
ethylene commercially available-from DuPont~ N~
; 5~ acr~11c acid ~ 10%
': ~
- ~
-' ' ' ' ' ~ :
'.
'~
'~ ' '., ' ~, The samples so produced were subjected to the foliowing test methods -TEST MET ODS
(i) Water U~take ~
The tendency of polymerio compositions to absorb water may render the use thereof in certain applications unsuitable~
particularly in electrical insulation applications and especially flame retarded systems wherein reliance is placed on hydrated alumina fillers to provide flame retardancy.
The present invention is concerned with reducing or elimin-ating the tendency of hydrated alumina filled polymeric compositions to absorb water, hereinafter referred to as "water stabili~ation" and the expression "water stabiliser"
is to be construed accordingly.
A first aspect of the present invention provides a water stabilised polymeric compositionj inoorporating a hydrated alumina filler as cne component, an effective amount of an antimony V compound as another component, in which one or each of the components is/aré coated with a reagent which can chemlcally react with, or physically bond to, the surface of the other component.
:
A aecond aspect of the present invention provides water stabilised hydrated alumina whioh includes an effective . ~ .
~ - - amount ~of an antimony V compound and in which one or each . . . ~ .... .. .
" .' "
, , ' :
--' 1167991 of the hydrated alumina and the antimony V compound components is/are coated with a reagent which can chemically react wlth, or physically bond to, the surface of the other component.
A third aspect of the present invention provides a process for producing a water stabilized hydrated alumina in which the hydrated alumina is treated with an effective amount of an antimony V compound and wherein one or each of the hydrated alumina and the antimony V compound components is/are coated with a reagent which can chemically react wi-th or physically bond to the surface of the other component.
A fourth aspect of the present invention provides a water stabilized dimensionally recoverahle, and especially heat-recoverable, article comprising a water stabilized polymeric composition incorporating a hydrated alumina filler as one component and an effective amount of an antimony V compound as another component, in which one or each of the components is/are coated with an acid, a reactive acid derivative, or a complexing or chelating a~ent.
A fifth aspect of the present invention provides electrical equipment, for example a wire or cable, or a high voltage in ulator, incorporating as electrical insulation a water stabilized polymeric composition incorporating a hydrated alumina filler as one component and an effective amoun-t of an antimony V compound as another component, in which one or each of the components is/are coated wi-th an acid, a reactive acid derivative, or a complexing or chelating agent.
:
, .
.
- . : . : , . ' 67g~1 The particulate fillers that may be employed in the composi-tions of the present invention are those which have a tendency to absorb water at least after incorporation into the composition. Particularly important classes of fillers include hydrated aluminas used as inorganic flame retardants and electrical anti-tracking agents, especially hal~gen-~free such fillers. Preferred fillers are hydrated aluminas of the formula Al203. x H20 wherein x is 0.5 to 3, for example alumina mono-hydrates e.g. Al203.H20, but especially alumina trihydrate Al203.3~20. In this specification the term hydrated alumina is also intended to include materials which are known as aluminium hydroxides e.g. Al(OH)3 and aluminium oxyhydroxides e.g. AlO.OH. Other suitable hydra-ted alumina fillers include ammonium and sodium dawsonite.
Mixtures of hydrated alumina fillers may be used if desired.
The hydrated alumina filler used iG preferably selected from those having a surface area of at least 0.1m2/g7 up to 300mm2/g and most preferably having a surface area of from 0.1m2/g to 100m2/g, particularly 2 to 40m2/g, and especially 4 to 16m2/g, as measured by the B.E.T. methGd~ Outstanding improvements in the electrical properties of filled polymer compositions containing high surface area alumina trihydrate f illers may be achieved~using the present invention.
.
The amount of filler incorporated in the compositions of the invent:ion will naturally depend inter alia on the nature ~: .
.. .. . . . .
- . .
.
g ~
thereof although in general, amounts in the range 5 to 80%, more preferably 20 to 70~, especially 30 to 70%, eOg. 40 to 70% based on the weight of the composition, are preferred.
Whilst we believe that insolubilisation of residual sodium in the filler plays a role in water stabilisation by anti-mony V compounds, the complete mechanism of water stabili-sation is not fully understood and will vary depending on the nature of the insolubilising agent. It is conjectured that in addition to forming a water insoluble compound with any available sodium present, the antimony V compound may also function as a water stabiliser by forming a water barrier around the filler particles thereby inhibiting water access to any hygroscopic moieties in the hydrated alumina even when the antimony V compound is not pre-coated onto the filler. Furthermore, and depending on the nature of the filler and antimony V compound, we believe, that such water :
barrier may be the result of interaction between the antimony V compound and the surface of the filler particles.
Although not essential, it is preferred that the level of sodium impurity in the hydrated alumina should be reduced to :~:
a minimum. This may be~ achieved by pre-treatment, for ` example, washing with~water~or an aqueous medium particu-`~ larly ~aqueous inorganic or organic acids, e.g. to a total sodium~level less than 1000 ppm, more pre~erably less than , ; 600 ppm of sodium mea ured as Na2O, based on the weight of ` ~ the hydrated alumina.
.. ,, ..~ .., 799 i - `6 - RK109/128 , Reduction of the sodium impurity level may also be achieved by pre-treatment of the filler with a sodium complexing or chelating agent such as particularly zinc or magnesium uranyl acetate, but also uranic acid, molybdic acid, orthophosphoric acid, hypophosphorous acid, dodecamolybdo-phosphoric acid and polydentate ligands such as polyketo-nates. Such treatment is normally followed by washing of the filler to remove any water soluble compounds thus formed.
Many conventional polymer processing methods involve milling, internal mixing e.g. in a Banbury mixer, or other treatment stages likely to cause some break-up of the filler particles thereby exposing sodium ions prev1ously trapped within the crystal latticP. It will be appreciated therefore that for many purposes merely reducing the soluble sodium content of the filler prior; to bl~ending with the polymer is not suffi-cient to water stabilise the filled polymer system.
~he antimony V compound may be incorporated by distribution thereof throughout the composition or alternatively the particulate filler may be treated by coating therewith as appropriate.
~owever,~it~has been found that greatly improved results are , obtained if the hydrated alumina, an efféct~ve amount of the antimony V compound, anù the polymer, are processed to~ether, fo~ example on a mill or in an internal mixer, for . : . ~ .
' ' :
fi7~g ~
- 7 - RK109~128 an extended period of time. Such processing i~ preferably carried out f~r at least 5 minutes, and preferably from 10 to 60 minutes. Alternatively, the hy~rated alumina may be treated with the antimony V compound prior to blending with the polymer9 Suitable antimony V compounds include, for example the hydrated forms of antimony V oxide, especlally the monohydrate Sb2O5 H2O, antimony alkogides, for example antimony V pentamethoxide, and antimony pentahalides, for example antimony pentachloride. The treatment step may require to be followed by a waghing treatment with an aqueous or organic solvent depending upon the antimony V
compound used but at least in the case of the hydrated antimony V oxides this is not essential.
Whatever the mechanism of the water stabilisation ~by the antimony~V compound, it has been found in accordance with this invention that further improved results may be obtai-ned when the hydrated alumina or the antimony V compound, or both, is/are coated with a reagent which can chemically react with or physically bond to the surface of the other.
Thus`where the hydrated alumina is coated, the reagent is one that can chemically react with or physically bond to the surface of the antimony V compound, and vice versa. It is postulated~that the functio~ of the coating reagent is in~some ~way ~to~lmprove the interaction of the an~imony V
compound with~the surface of the hydrated alumina, thereby :
9 9 ~
assisting in the insolubilisation of residual sodium or water barrier ~ormation as previously discussed. Thus the coating reagent should be one that i3 capable of forming a covalent bond, a complex, or at least providing attractive ~orces, for example Van der Waals forces, between the antimony V compound and the surface of the hydrated alumina.
As examples of reagents which may be employed to coat the surface o~ the hydrated alumina and/or the antimony V
compound there may be mentioned acids,both organic and inorganic, and reactive functional acid derivatives, e.g.
esters, acid halides and anhydrides, and complexing or chelating~ agents including polydentate ligands such as ~-polyketonates and Schif~ base (imine3 derivatives thereof.
:
.~
Examples of organic acids incIude mono ~ or polybasic , substituted or unsubstituted carboxylic, thiocarboxylic or sulphonic acids such as monobasic C2-C20 pre~erably C3-C20 acids, e.g. acrylic, acetic, n-propionic, n-butanoic, , n-hexanoic,~ n-octanoic,~lauric and stearic acids, aromatic acids, e.g. benaoic acid and polybasic C2-C20 acids, e.g.
oxalic,~maleic,~fumaric, malonic, succinic and itaconic - .
acids and derivatives such as the anhydrides and monoesters, especlally mono-alkyl or a-alkenyl esters, thereof.
- . , ~ . :: ~, , :
~ !
.
~ ~B7991 Examples of substituted mono - or polybasic carboxylic or thiocarboxylic acids are amino acids, e.g. glycine, alanine and phenylalanine and hydroxy, parti~ularly a-hydroxy, acids, such as lactic acid, salicylic acid, tannic acid and citric acid, especially citric acid.
Examples of inorganic acids include dilute mineral acids such as hydrochloric acid as well as phosphoric acid, molybdic acid, hypophosphorous acid and telluric acid.
Suitable polyketonates and Schiff base derivatives include those derived from polyketones of formulae R-CO-CH2 ( CO-CH2 ~m-CO-R
Where R and R1 are the same or different and can ~ be alkylp alkenyI, aryl or alkaryl group~
and m = O or an integer.
Examples of such compounds include acetyl acetonep allyl a~eto-acetonate, di-acetyl acetone, benzoyl acetyl acetone, :
dibenzoyl acetone,~ and benzoyl allyl aceto-acetonate. A
suitabIe Schiff base~derivative is:
--~ H3coc~2cocH:c(cH3)N8cH2]
: ~ , i ,.
. . ~
-.
~1 l67~
Furthermore, by appropriate choice of coating reagent, the treatment may addi~ionally serve to reinforce the composition, for example by employing u~nsaturated reagents, particularly unsaturated carboxylic or thiocarboxylic acids or functional derivatives thereof, such as acrylic, meth-acrylic, vinylacetic, allylacetic, fumaric, maleic or itaconic acids, or unsaturated esters, e.g. allyl es~ers of polybasic, particularly dibasic, acids, e.g. the rnono-allyl ester of malonic, maleic or succinic acids, whereby the unsaturated function enables grafting of the reagents to the polymeric matrix of the composition.
Under certain circumstances, various desirable properties may be opt~imised by the use- of a plurality of pre-coating reagents. Thus a combination of acryIic and stearic acids : ~ :
permi~s a satisfactory balance of physical and water stabilisation propèrties~
The amount of coating reagent(s) employed preferably lies in the range 0~1 to 15 weight per cent, more prefer-ably-1 to 10 weight~ per cent based on the weight of the fiIler~ ~
, Of the posslble antimony V compounds, including antimony V
comple~xes~, which may be employed in the compositions of the present ~invention~particularly preferred are the hydrated .
.
, , . . .
~B799~
~ RK109/128 forms of antimony V oxide, especially the monohydrate, i~e.
Sb2O5.H2O, and precursors thereof. Such precursors include compounds which during processing or by other chemical or physical treatment may be converted into a hydrated antimony V oxide. However good results may also be obtained using antimony V alkoxides, for example antimony V pentamé~hoxide.
The antimony V compound is present in an amount effective to improve the water stabi1ity of the composition, said amount being preferably in the range 0:1 to 60 weight per cent based on the composition, more preferably 0.1 to 25 weight per cent, although for water stabilisation purposes only, it has been found that amounts in the range 0.1 to 10 weight per cent e.g. 0.5 to lO weight per cent are quite satis-factory. However, it has also surprisingly been found that whilst lower amounts have~ no substantia1 positive effe~t~on flame retardancy of the composition and indeed, in some instances a depression of flame retardance is observed, in higher amounts, e.g. above 5 weight per cent, preferably from 10 to 25 weight per cent, especially 10 to 15 weigh~
per cent based on the composition, a substantial increase in .
flamè retardance is observed a~ elevated temperatures, i.e.
as measured by the British Ministry of Defence specification NE5 7l5~ base~d~ on ASTM-D-2863) whilst still providing satlsfactory water ~tabilisation.
., ~ , , ': , ~ ' " `' `
~ ~ B79~ ~
Polymeric compositions wherein the water stabilisers have ~een found to exhibit notable efficacy in reducing water absorption include non-cross-linked and cross--linked thermoplastic or elastc~eric substituted or unsubstituted pol~aIkenes or alkene oopolymers, such as alkene/aIkene copolymers, vinyl ester hcmo - or co-polymers and (meth)acrylate homo - or copolymers.
The term "copolymer" as used herein is employed in a broad sense to mean any polymer containing at least 2 different monomeric species and includes ter-polymers and the like.
Unsubstituted polyalkenes and aIkene copolymers of interest include polyethylenes and aIkene/alkene ~opoly~iers such as ethylene/alkene copolym~rs, especially those disclosed in UK Patent Application No. 2019412A and Canadian Patent No. 873,828 and elastomers such as EPDM (ethylene/propylene/diene manomer) and SBR (styrene/
butadiene rubker).
The vinyl ester homo - or copolymers of int rest are those derived from vinyl ester moncmers ot forTLla I, .~.
~ ' " ,: , 79~1 ~ 13 - RK109/12 / C = C \
R2 O - C - R ~
..
o wherein R1, R2 and R3 are each, independently hydrogen or a substituted or unsubstituted hydrocarbon group having up to 20 carbon atoms, e~g.~ C1 -- C6 alkyl, and R4 is a subatituted or unsubstituted hydro-carbon group having up to 2:0 carbo~ atoms, : :
which may optlonally include one or more ~ hetero atoms,~ :especlally where R~ R2 and R3 are each~1ndepen-dently h~drogen or C:1 - C6 alkyl,: and~
one~ of~R1, R2 and R3 may~a}so s1gnify ~ -~
phenyl: or benzyl, and R4 is an alkyl, : ~ :
alkenyl, alkoxya1kyl~or alkoxy-alkenyl, :aryl or aralkyl group having up to 20 carbon atoms e.g. phenyl, naphthyl or benzyl, or C1~- C4, alkyl - or alkoxy- ~ ;
.phenyl::~or~ben~zyl, and particularly when :
R4~ s~C1~-;Cj5 alk~l, phenyl or - : , - i '' ~ ' , .
' ``` 1~79~
- 14 - RK109/~28 .
Examples of specific vinyl ester monomers useful in the polymers of in~erest are vinyl acetate, vinyl propionate, vinyl hexanoate, vinyl octanoate, vin~l versatate, vinyl stearate, vinyl laurate, vinyl methoxy-acetate, vinyl trimethylacetate, vinyl isobutyrate, vinyl tert. pentoate, vinyl lactate, vinyl caprylate, vinyl pelargonaté, vinyl myristate, vinyl oleater vinyl linoleate, vinyl benzoate, vinyl (C1 - C~) alkoxy benzoate, vinyl octylphthalate, vinyl ~-phenyl butyrate, vinyl ~-naphthoate, vinyl ethyl phthalate and vinyl phenyl aeetate.
Vinyl ester copolymers of interest include mixed vinyl ester copolymers e.g. copolymers of vinyl acetate wi~h higher vinyl esters, e.g. vinyl laurate as well as copolymers wlth comonomers other than vinyl esters. Other such comonomers include unsaturated hyd~rocarbons such as ole~ins e.g.
ethylene, propylene, particularly C4~ - C12 ~-unsaturated olefins, e.g. but-l-ene, hex-l-ene and oct-l-ene, styrene and unsubstltuted or substituted esters, e.g. Cl - C12 (meth) acrylates and other vinyl monomers, e.g. vinyl chloride.
When copolymers wlth comonomers other than vinyl esters are employed, then preferably the vinyl ester monomer~s) is present in at~least 5;mole %, preferably at least 10 mole %, e.y. 20 - 95 mole %, more pre~erably at least 30 mole ~, .
~e.g. 40~- 95 mole %.
.--: : ~: . "
e79~1 - 15 -' RKlO9/128 The (meth) acrylate homo - or copolymers of interest are those derived from (meth) acrylate monomers of formula I I , - CH2 = C I I
\C - O - R6 n O
wherein R5 is H or CH3 and R6 is a substituted or unsubstituted - hydrocarbon group having up~to 20 carbon atoms~, which may optionaIl~ include one or.more-hetero atoms, preferably an ..
alkyl, alkenyl~, alkoxyalkyl or alkoxy~
alkenyl.~aryl o~:aralkyl group having up to 20 carbon atoms, e.g. phenyl, naphthyl or benzyl, and particularly ~ C1 - C15~ alk~yl, phe:nyl or benzyl.
Preferred homo~ polymers~lnclude polyethyl acrylate, poly- ~ ~ ;
butyl:~:acrylate. :~Partlcularly prefe;rred (meth)acrylate copolymers~are:ethylene/ethyl acrylate (18 weight per cent), ~ethylene/ethyl~methacrylàte (20 weight per cent) and ter-polymers:~of~ethylène, methyl acrylate and a cure-site .
7113~
carboxyl-containing mono~er such as the terpolymer c~om~rcially available from D~Pont under the trade name "Vamacl'* and analogous polymers described in UK
Patent No. 1,548,232. Other copolymers suitable for use in the present inve~tion include those derived from any of the above ~entioned monomers and a cure site mono~er such as 2-chloroeth~l vinyl ether or 2-chloroethyl acrylate.
Okher polymers of interest which }nay be employed in the ccmpositions of the invention include epoxy resins especially cycloaliphatic epoxy resins such as those employed for high voltage insulation applications, e.g. Araldite* CY175 and Bakelite* FRC 4221 especially when cured with cycloaliphatic acid anhydrides e.g. hexa-hydr~ phthallic anhydride, unsaturated polye~ters especially glass filled polyesters, and polyamides especially aliphatic polyamides such as nylons.
Furthermore, such polymers may be e~lployed as a blend system containing other polymers. Preferred polymer blends are those compris~ng vmyl ester homo - or ccpolymers, (meth)acrylate homo - or copolymers, and/or substituted or unsub-stituted polyalkenes or alkene copolymers. Blend polymers of interest are those which are preferably ccmpatible, either alone or in assod ation with compatabiliS-ing agents, with the aforedescribed polymers and which do not render the composi-tions unsuitable for the purpose for which they are intended. Such blends may include blends of two or more of the aforedescribed polymers or blends with other polymers including thermoplastic and elastomeric polymers, examples of which are polyesters and polyethers including segmented polyether ester copolymers of the type available from DuPont under the trade name Hytrel and described in Polymer Engineering and Scienoe 14 volume 12, 848-852 1974 'ISegmented Polyether Ester copolymers - a new generation of high performanoe elastomers", silicone resins and elastomers and acrylic elastDmers. Some preferred polymer blends are des-cribed and claLmed in UK Patent No. 1,284,082 and in Genman Offenlegenschrift No.
2815520.
*trademark - 16 -, , -- . . . . .
- ~ ~ :. . ' , , .
B799iL
In the case of vmyl ester or (meth)acrylate polymers, when blends are employed s~lch poly~ers are preferably present in the blend in at least 20 weight per cent, e.g. 30 - 99 weight per oent, more pre~erably at least 40 wei~ht Fer cent, e.g.
50 - 99 weight per cent.
me polymer composition may also contain other additiv~s such as organic halogen containing or morganic flame retardants, or organo-phosphorous ccmpound5, anti~
-tracking agents, high voltage erosion suppressants, stahilisers, e.g.
.
: .:
.
679g 1 - 18 - RK1~9/12~
antioxidants and ultra-violet stabilisers, illers, pig-ments, colourants and the like. In general it is pre~erred that the composition contain little or ~o halogen, e.g. less than 15 weight per cent based on the composition, more preferably less than 10 weight per cent, especially less than 5 weight per cent of halogen atoms.
~or most purposes, it is preferred that the compositions o~
the invention are substantially cross-linked.
The degree of cross-linking of the compositions may be èxpressed in terms of the gel content (ANSI/ASTM D2765-68) of the cross-linked polymeric composi~ion, i.e. excluding non-polymeric additives that may be present. Preferably the ge~l content of the cross-linked composition is at least 10%~
~ : ,.:
more preferably at least 2~0%~ e.g. at least 30~ more preferably at least 40~
The compositions of the invention are produced in conven-tional manner,~for example by blending together the compo-nents of the composition in a Banbury mixer.
They may then be processed~into shaped articles, for example by~extrusion or moulding~ and wh0n desired simultaneously or ~subsequently cross-linked. Shaped articles so produced also form part of the present inventlon.
"
~: :
: ::
.
.
: , , ~79g~
When desired the polymeric components of the ccmposition may be cross-linked either by the incorporation of a cross-linking agent or by exposure to high energy radiation. Examples of suitable cross-linking agents are free radical initiators such as peroxides for exa~,ple, dicumyl peroxide, 2,5-bis-(t-butyl-peroxy)-2,5-dimethylhexane, 2,5-bis-(_-butyl~peroxy)-2, 5~dimethylhexhyne-3, and ~,~-bis(_-butyl-peroxy)-di-iso propylbenæene. O*her examples of appropriate cross-linking agents are disclosed in C.S. Sheppard & V.R. Kamath Polymer Engineering & Science 19 No. 9 597-606, 1979 "The Selection and Uæ of Free Radical Initiators". In a typical chemically cross-linked ccmposition there will be about 0.5 to 5 wcight per oent of peroxide based on the weight of the poly-meric composition. me cross-linking agent may be employed alone or in associa-tion with a co-curing agent such as a poly-functional ~inyl or allyl cGmpound, e.g. triallyl cyanurate, triallyl isocyanurate or pentaerythritol tetra meth-acrylate.
Radiation cross-linking may be effected by exposure to high energy irradiation such as an electron beam or y-rays. Radiation dosa~es in the range 2 to 80 ~rads, preferably 2 to 50 Mrads, e.g. 2 to 20 Mrads and particularly 4 to 15 Mrads are in general apprcpriate.
.
.
: ' . ' '. ' ~1 1fi7~
For the purposes of promoting cross-linXing during irradia-tion pre~erably from 0.2 to 5 weight per cent of a prorad such as a poly-functional vinyl or ~llyl compound, for example, triallyl cyanurate, triallyl isocyanurate or pentaery~hritol tetramethacrylate are incorporated into the composition prior to irradiation.
The compositions of the invention are particularly suitable for electrical insulation use, e.g. where flammability requirements are stringent or high voltage anti-tracking properties are desired and water absorption highly undesir-able, for example wire and cable applications in confined areas such as aircraft, ships, mines or railways including metro systems, or termination and splicing of high voltage cables or as insulation in non-track1ng high voltage appli-cations, e.g~ insulators, bushings and bus bar systems.
The production of electrical insulation material may be achieved by conventional techniques, for example by extru-sion of the non-cross-linked composition, as an insulator, : :
onto the electrical equipment such as a copper conductor as a~primary insulation,- or a~ bundle of primary insulated copper wires as~ a; cable j~acket and preferably, simultan-eously or~subsequently cross-linking the applied insulation.
As aforedescribed, the~ compositions of the present inven~ion are also particularly suitable in cros~-linked form for the .. .: ~
-.
-.
.
:
~ 1~79g'~
production of dimensionally recoverable articles, that is to say, articles, the dimensional configuration of which may be made substantially to change when sub~ected to an appro-priate treatment. of particular interest are heat-recover-able articlesl the dimensional configuration of whlch may be made substanti~lly to change when subjected to heat treatment.
Heat-recoverable articles may be produced by deforming a dimensionally heat-stable coniguration of the article to a dimensionally heat-unstable configuration, the article assuming or tending to assume the heat-stable configuration thereof on the application of heat alone. As is made clear in US Patent No. 2,027,962, however, the original dimen-sionally heat-stable configuration may be a transient form in a continuous process in which, for example, an extruded tube is expanded, whilst hot,- to a dimensionall~ heat-unstab?e form~
'~
Alternatively a preformed dimensionally heat-stable article may be deformed to a dimensionally heat-unstable orm in a separate stage. In the production of dimensionally recover-able articles, the-~composition may be cross-linked at any stage in the-production process that will acomplish the desired dimensional recoverability. One mannér of producing a heat~recoverable article comprises shaping the pre~cross-.
: ~llnked~ compositlon lnto the desired heat-stable form, `~ subsequently cross-linking the composition, heating the . , : ~ ~ -- . ' ' " ': . ~ : , , ' '' a~7s~
article to a temperature above the crystalline melting point or~ for amorphous materials ~he softening point, as the case may be, of the polymer, deforming the~article and cooling the article whilst in the deformed state so that the de-formed state of the article is retained. In use, since the deformed state of the article is heat-unstable, application of heat will cause the article to assume its original heat-stable shape. Such dimensionally recoverable articles may be employed as Elame retarded and/or ~nti-tracking sleeves for covering and/or sealin~ splices and terminations in electrlcal conductors, for environmentally sealing damaged regions or joints in utility supply systems, e.g.
gas or water- pipes, district heating systems, ventilation and heatinq ducts and conduits or pipes carrying domestic or industrial effluen~.
Adhesives and seal'ants in accordance with the fourth aspect of the invention are particularly those which find use in electrical applications for example iD harnesslng systems, and especially ln high voltage applications wherein anti-tracking'fillers such as 'h~ydrated alumina are employedO
Preferred sealants include elastomer/tackifier formulations . ~ , , .
such as butyl rubber/polyisobutylene or epichlorohydrin ~: , ^ :
rubber/polyketone~resin compositions. Preferred adhesives include epoxy, especially cyclo aliphatic epoxy and silicone based adhesives.~
,: ' . ' , : ' ' ' .
, ~,`, . ' .
'~ ' . ' ' .
1 ~79g l Panelling and cladding materials in accordance with the fifth aspect of the inven-tion include materials such as those disclosed and claimed in UK Patent Applica-tions Nos. 2035333A and 2044777A, as well as epoxy m~ulding cc~positions and unsaturated polyesters particularly when glass-fibre rein~orced. Such materials may be processed into final shape by thermoforming, e.g. by vacuum forming, mould-ing or laying-up techniques.
me invention is illustrated by the accompanying examples wherein parts c~nd per-centages are by weight and te~peratures are expressed in &.
I ~ g ~ ~
- 24 - RK10g/128 The compositions set out in Table 1 bel~w were compounded on a 2 roll laboratory mill heated to a temperature of 120 -140, and moulded at 170 into test plaques of 2mm thickness Each composition incorporated 40% ~compositions H and I) or 60% (compositions A to G) commercial fire retardant grade Al2O3. 3H2O which had been pre-coated with the reagents disclosed in Table 1 and the indicated amount of commercial grade Sb2O5. H2O. The test plaques were then irradiated with a 5.8 MeV electron beam to a total dosage of 12 Mrads.
The composition of each formulation employed is set out in Table 1 below which shows the number of parts of: each cons~ituent.
- : ~ : : :.
- : ~
, `: . ~
. . , ' '' ' ~
, ~ :
~' . "~ ' . ' ' "''' " ' ' ' ', ,' ":
~, .~ 111679~
- RK109/l28 TABLE l COMPOSITION POLYMER FILLER COATING sb20s. HzO
(Wt %~of filler) (Wt % of filler~
A 60% vinyl acetate/40% 5% acrylic ac;d 5%
ethylene copolymer B Il . 5% acrylic acid lO%
C '' 1.3% oleic acld 5%
D " 2% stearic acid 5%
E " 66% of filler coated lO%
~ith 2% of stearic.
acid and balance coated with 3% of acrylic acid F " lO% stearic anhydride 2%
G " 5~ citric acid 2%:
H ~ SCLAIR 8105 (Trade Name~- 5%:acryl~ic: acid 5%
L.inear low:density poly~
ethylene commercially available-from DuPont~ N~
; 5~ acr~11c acid ~ 10%
': ~
- ~
-' ' ' ' ' ~ :
'.
'~
'~ ' '., ' ~, The samples so produced were subjected to the foliowing test methods -TEST MET ODS
(i) Water U~take ~
3 test discs 2.5 cm in diameter were employed to determine water uptake by immersion in water at 90 (compositions C to G) or 50 (remaining compositions).for various periods. At the end of each period, the discs were removed, excess water . ~ . .
wiped off~ the discs weight and the percentage weight in-crease computed.
(ii) PermittivitY after immersion in water at 50 ... . .~
In accordance~ with BS2782, Method 206B.
(iii)~Tensile st~ longation rn accordance~with~IS037 employing a~ strain rate of ~10 cm/mlnute~ and ~type ;2 dumbells.
(iv~ lammability In~accordance with the limiting Oxygen Index ~LOI) method o~
ASTM-D-Z863.
, .: .~
: :: ;
, . . .
: -.
Ifi7g91 The results are set out in Table II below. For comparison purposes, the results for control samples incorporating no Sb2O5. H20 and 60% uncoated Al2O3. 3H2O~are given.
!
.
, ~ :
:
' . . ~ .
1 ~ 7 9 9 ~
TABLE II
% WATER UPTAKE PERMITTIVITY _TENSILE ELONGATION LOI ~ 23C
COMPOSITION STRNGTH @ 23 (%) @ 23 (%) (MPa) hours hours hours hours hours hours A 3.05 4.635.31 3.31 4.30 7.15 14.59 144 29.0 B 2.24 3.424.93 4.46 5.71 7.71 16.22 146 28.6 C 4.1 3.4 - ~ 5.4- 468 D 1.0 0.9 - - - 4.4 448 E 0.5 0.6 - 4.54 4.45 4.51 - - 42.0 F 1.0 1.8 - 4.15 4.79 5.47 - - 32.3 G 3.4 0.87 - - ~ - 48.0 CONTROL 7.44 7.44 6.13 ~ 4.04 55.67 20.85~ 4.96 288 44.7 H 0.22 0.68 ~ 0.80 ~2.44 ~ ~.17 ~ 3.05i 15.86 ~ 221 19.5 I 0.25 0.64 0.~69~2.632.38 2.75` 15.13 184 ~ 19.5 CONTROL 0.65~ 1.60 1.352.44 14.44 28.57~ 14.65 42 22.5 , ' ~ :' ` ' . " ' ~ ' :' , :~ :, ` :
- `~
- 1~679~
-Test plaques were made up in analogous manner to that described in Example 1 and subjected to water immersion at 90 for 7 days. Permittivity (per BS2782, method 206B) and electric strength (per BS27B2, method 201C) before and after immersion were measured. The composition o the formula-tions tested are as set out in Table III and the results are set out in Table IV.
' Compositions N and P were also extruded as 1 inch tubing, irradiated and expanded to produce heat-shrinkable articles useful respectively for the termination of high voltage power cables and for bus bar coverings.
~ ' , :: :
.
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~ 30 TABLE III
_~
FORMULATION - PARTS
CONSTITUENT ~ . _ .
N O(CONTROL) P Q(CONTROL) _~
DYNH-3 (TM-low density poly- 22.90 22,90 34.42 34.42 ethylene available from Union Carbide) .
, Ethylene/ethyl acrylate (18%) 22.89 22.89 _ copolymer . -.
~olydimethylsiloxane elastomer Z .8~ 22.89 _ _ .. .
Royalene-611 (TM-EPDM rubber _ _ 34.42 34.42 available from Uniroyal) .
, . :
Fe203 3.81 3.81 0.86 0.86 ,.
Agerite-D (TM-antioxidant 1.52 1.52 0.69 0.69 available~from Vanderbllt) ~ ; :
Triallyl cyanurate - ~ 0.77 0.77 _ _ ~ ' . .
Trimethylolpropane tr;methacrylate _. 0.69 0.69 .
. Aerosil 200 (TM-silica availa~le . _ 1.38 1.38 from Degussa) . :
. . . : : : ., Al203-3H20 ~ ~ . ~ ~:Z5.18 _ 27~54 :
' ~ ' -. .
Al203.3H20 precoated with 1% : 24.42 _ 26.71 _ :~ thereof acrylic acid ~ - : :
: ~ ~.~6 _ 0.83 _ , .
. ~ . . .
' -.
1 ~ ~7~ ~
_ 31 -TABLE IY
. -~ . ~
PERMITTIVITY ELECTRIC STRENGTH ~KV/cm) FORMULATION ____________ ~ ~
. BEFORE AFTER BEFORE AFTER
_~ ~ ~ _~_ ~_ N . 2.6 5.5 198.1 93.2 O 2.7 9.6 187.1 66.g ~ . .
p 2.4 3.1 177.9 144.9 . ' ~ .
. Q (CONTROL) 2.5 : 3.8 201.4 99.6 ~ _ .~.. . __ ~
- . - . . ~ . `
.. . . .. ...
. ' . . , :
l ~B799 1 -- 32 - RK10~/128 The compositions set out in Table V be~ow (~hich shows the number of parts of each constituent) were compounded on a 2 roll laboratory mill heated to a temperature of 120 -140, and moulded at 1 sao into ~est plaques of 2mm thick-ness. The test plaques were then irradiated on a 5.8 MeV
electron beam to a total dosage of 12 Mrads. 3 test discs 2.5cm in diameter were cut out of each plaque and the discs were employed to determine water pick-up by immersion in water at 90 for various periodO At the end of each period, the discs were removed, excess water wiped of~ and the discs weighed. The results are listed in Table VI ~elow each result reported being the average result for three identical discs~.~ YES in Table: _ indicates that the alumlna~ trlhydrate has been treated, before compounding, in the manner descr bed below.
.
,:
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- 33 ~ RK10g/128 In examples B, E, H and K, the alumina trihydrate ~iller was treated by violently agitating 200g thereof whilst adding 5ml of glacial acetic acid as a fine s~ray over a period of S minutes, before compo~lnding.
In examples C, F, I and L, the alumina trihydrate filler was treated by violently agitating 200g thereof whilst adding 5ml of glacial acetic acid as a fine spray over a period of 5 minutes and then dry-blending with 10.5g of Sb205.H2O for 5 minutes. The mixture was then ~laced in a vacuum oven at 140 overnight. It is postulated that this treatment results in the partial esterification of the hydroxyl groups of surface alumina trihydrate molecules of the particulate filler and that these molecules function, possibly as bidentate ligands, to co-ordinate to the Sb2O5.H~O effec-tively to form a surface~ complex-containing coating on the filler particles. ~he alumina trlhydrate so treated is compounded as described above.
In example M a similar treatment of the alumina trihydrate was adopted aa~ for~examples C, F, I and L except 5ml of acetylacetone~was employed lnstead of glacial acetic acid.
. ~
In examples~ D, E, F, J, R and L the alumina trihydrate employed before acid treatment is a commercially avallable form ~containing a partial surfa~e coating (1.5~) o~ the ;., :
.
67g~
silane coupling agent vinyl trimethoxyethoxysilane. Exam-ples 1 to 6 are based on 40 parts of ethylene/ethyl acrylate copolymer (containing 18~ ethyl acrylate) and 60 parts of inorganic filler.
Examples G to L are based on 40 parts of a vinyl acetate/
ethylene cop~lymer containing 60 weight per cent vinyl acetate, and 60 parts of inorganic filler.
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~ : ' 67~9 ~
TABLE V
-EXAMPLE No. .
CONSTITUENTS A B C D E F G H I J. K L M
Ethylene/18% ethyl acrylate copolymer 40 40 40 40 40 40 60% vinyl acetate/
ethylene copolymer 40 40 40 40 40 40 40 Al203.3H20 60 60 60 ~ 60 60 60 60 , : : :
Al203.3H20:coated with 1.5% vinyl trime~
thoxyethoxy~silane ~ 60 60 ~ 60 ~ 60i 60 6Q ~ ~ :
Glacial acetic acid treatment of flller ~ YE5 YES~ ~ YE5~ :YES~ YE5: YE5 ;~ YES YE5 Sb205.H20 trea~ment of coated f;ller ~ YES~ ;YE5 ~ YES YES YES
Acetylacetone :treatment of filler ~ YES
- : : :: ~ . . . .
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- 3~ -TABLE VI
.
% WEIGHT UPTAKE AFTER IMMERSION IN WATER AT 90C FOR
EXAMPLE _ _ ~ __ A 7~.1 19.5 B . 7.7 la.3 C 4.5 ~.8 D 2.0 - 4.3 .
E . 4.8 6.5 F . 1.. 3. 2.5 .
~ - 20.~ 14.2 H ~ 21.9 ~ 21.3 ~ 5 8 ~ ~ a 4 K: : . ~ 5.2 ': : ~ g.4 L ~ - , ~ 1 . 2 ~ ~ 0 . 9 M - ~ 1.9 : 2.2 : - .
._. ~
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.
.:
11 B79g ~
The results shown in Table Vl d~monstrate a dramatic de-crease in water uptake in Examples C, F, I, L and M prod~
u~ed by the antimony (V) complex coati~g, when compared to analogous systems in tùe sbsence oi I complex coating.
.
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. . ' ' ' ' .
1 11~7~9~
38 - RK109!128 700 gms. of high surface area (13m2/g) alumina trihydrate were dispersed in 7 litres of:-(i) Triply distilled water.
(ii) Triply di3till~d water to which 35 grams ofzinc uranyl acetate had been added.
.
and vigorously agitated for 3 hours at 80 ~ 85'C. The washed ALTH was recovered by ~iltration and washed dried under vacuum and ball milled. This yleIded material with physical properties (e.g~. T.G.A. curve, surface area etc) similar~ to~tho~e~of the stsrting mstsrlal. The~ recovered ~ "~
ALT~ was (aj compounded with 40~ by weight of a 60% vinyl acetate /40% ethylene copolymer as described in Example 1, (c)~coated; with 5% acrylic acid and 10% antimony pentoxide .
monohydrate before compounding with 40% by weight 60% vinyl acetate/40S sthylens copolymer or (b) ;coated only with 10%
antimony pentoxide~ before compounding with 40% by weight of a 60% vinyl acetate~40% ethylene copolymer. Table VII shows that~ the~beneflts of ths inventlon are observed even~when using-; ALTH which~ha~ been tr~ated to`remove soluble sodium impurity.
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Cl ~ . ' }-- S ¦ ' r~ C~ ~) a:) r - O
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.
wiped off~ the discs weight and the percentage weight in-crease computed.
(ii) PermittivitY after immersion in water at 50 ... . .~
In accordance~ with BS2782, Method 206B.
(iii)~Tensile st~ longation rn accordance~with~IS037 employing a~ strain rate of ~10 cm/mlnute~ and ~type ;2 dumbells.
(iv~ lammability In~accordance with the limiting Oxygen Index ~LOI) method o~
ASTM-D-Z863.
, .: .~
: :: ;
, . . .
: -.
Ifi7g91 The results are set out in Table II below. For comparison purposes, the results for control samples incorporating no Sb2O5. H20 and 60% uncoated Al2O3. 3H2O~are given.
!
.
, ~ :
:
' . . ~ .
1 ~ 7 9 9 ~
TABLE II
% WATER UPTAKE PERMITTIVITY _TENSILE ELONGATION LOI ~ 23C
COMPOSITION STRNGTH @ 23 (%) @ 23 (%) (MPa) hours hours hours hours hours hours A 3.05 4.635.31 3.31 4.30 7.15 14.59 144 29.0 B 2.24 3.424.93 4.46 5.71 7.71 16.22 146 28.6 C 4.1 3.4 - ~ 5.4- 468 D 1.0 0.9 - - - 4.4 448 E 0.5 0.6 - 4.54 4.45 4.51 - - 42.0 F 1.0 1.8 - 4.15 4.79 5.47 - - 32.3 G 3.4 0.87 - - ~ - 48.0 CONTROL 7.44 7.44 6.13 ~ 4.04 55.67 20.85~ 4.96 288 44.7 H 0.22 0.68 ~ 0.80 ~2.44 ~ ~.17 ~ 3.05i 15.86 ~ 221 19.5 I 0.25 0.64 0.~69~2.632.38 2.75` 15.13 184 ~ 19.5 CONTROL 0.65~ 1.60 1.352.44 14.44 28.57~ 14.65 42 22.5 , ' ~ :' ` ' . " ' ~ ' :' , :~ :, ` :
- `~
- 1~679~
-Test plaques were made up in analogous manner to that described in Example 1 and subjected to water immersion at 90 for 7 days. Permittivity (per BS2782, method 206B) and electric strength (per BS27B2, method 201C) before and after immersion were measured. The composition o the formula-tions tested are as set out in Table III and the results are set out in Table IV.
' Compositions N and P were also extruded as 1 inch tubing, irradiated and expanded to produce heat-shrinkable articles useful respectively for the termination of high voltage power cables and for bus bar coverings.
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~ 30 TABLE III
_~
FORMULATION - PARTS
CONSTITUENT ~ . _ .
N O(CONTROL) P Q(CONTROL) _~
DYNH-3 (TM-low density poly- 22.90 22,90 34.42 34.42 ethylene available from Union Carbide) .
, Ethylene/ethyl acrylate (18%) 22.89 22.89 _ copolymer . -.
~olydimethylsiloxane elastomer Z .8~ 22.89 _ _ .. .
Royalene-611 (TM-EPDM rubber _ _ 34.42 34.42 available from Uniroyal) .
, . :
Fe203 3.81 3.81 0.86 0.86 ,.
Agerite-D (TM-antioxidant 1.52 1.52 0.69 0.69 available~from Vanderbllt) ~ ; :
Triallyl cyanurate - ~ 0.77 0.77 _ _ ~ ' . .
Trimethylolpropane tr;methacrylate _. 0.69 0.69 .
. Aerosil 200 (TM-silica availa~le . _ 1.38 1.38 from Degussa) . :
. . . : : : ., Al203-3H20 ~ ~ . ~ ~:Z5.18 _ 27~54 :
' ~ ' -. .
Al203.3H20 precoated with 1% : 24.42 _ 26.71 _ :~ thereof acrylic acid ~ - : :
: ~ ~.~6 _ 0.83 _ , .
. ~ . . .
' -.
1 ~ ~7~ ~
_ 31 -TABLE IY
. -~ . ~
PERMITTIVITY ELECTRIC STRENGTH ~KV/cm) FORMULATION ____________ ~ ~
. BEFORE AFTER BEFORE AFTER
_~ ~ ~ _~_ ~_ N . 2.6 5.5 198.1 93.2 O 2.7 9.6 187.1 66.g ~ . .
p 2.4 3.1 177.9 144.9 . ' ~ .
. Q (CONTROL) 2.5 : 3.8 201.4 99.6 ~ _ .~.. . __ ~
- . - . . ~ . `
.. . . .. ...
. ' . . , :
l ~B799 1 -- 32 - RK10~/128 The compositions set out in Table V be~ow (~hich shows the number of parts of each constituent) were compounded on a 2 roll laboratory mill heated to a temperature of 120 -140, and moulded at 1 sao into ~est plaques of 2mm thick-ness. The test plaques were then irradiated on a 5.8 MeV
electron beam to a total dosage of 12 Mrads. 3 test discs 2.5cm in diameter were cut out of each plaque and the discs were employed to determine water pick-up by immersion in water at 90 for various periodO At the end of each period, the discs were removed, excess water wiped of~ and the discs weighed. The results are listed in Table VI ~elow each result reported being the average result for three identical discs~.~ YES in Table: _ indicates that the alumlna~ trlhydrate has been treated, before compounding, in the manner descr bed below.
.
,:
:
:. : ~ , :~
: ~ ~
- ~
~:
;
~1~7~9~
- 33 ~ RK10g/128 In examples B, E, H and K, the alumina trihydrate ~iller was treated by violently agitating 200g thereof whilst adding 5ml of glacial acetic acid as a fine s~ray over a period of S minutes, before compo~lnding.
In examples C, F, I and L, the alumina trihydrate filler was treated by violently agitating 200g thereof whilst adding 5ml of glacial acetic acid as a fine spray over a period of 5 minutes and then dry-blending with 10.5g of Sb205.H2O for 5 minutes. The mixture was then ~laced in a vacuum oven at 140 overnight. It is postulated that this treatment results in the partial esterification of the hydroxyl groups of surface alumina trihydrate molecules of the particulate filler and that these molecules function, possibly as bidentate ligands, to co-ordinate to the Sb2O5.H~O effec-tively to form a surface~ complex-containing coating on the filler particles. ~he alumina trlhydrate so treated is compounded as described above.
In example M a similar treatment of the alumina trihydrate was adopted aa~ for~examples C, F, I and L except 5ml of acetylacetone~was employed lnstead of glacial acetic acid.
. ~
In examples~ D, E, F, J, R and L the alumina trihydrate employed before acid treatment is a commercially avallable form ~containing a partial surfa~e coating (1.5~) o~ the ;., :
.
67g~
silane coupling agent vinyl trimethoxyethoxysilane. Exam-ples 1 to 6 are based on 40 parts of ethylene/ethyl acrylate copolymer (containing 18~ ethyl acrylate) and 60 parts of inorganic filler.
Examples G to L are based on 40 parts of a vinyl acetate/
ethylene cop~lymer containing 60 weight per cent vinyl acetate, and 60 parts of inorganic filler.
,, ' , :
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~ : ' 67~9 ~
TABLE V
-EXAMPLE No. .
CONSTITUENTS A B C D E F G H I J. K L M
Ethylene/18% ethyl acrylate copolymer 40 40 40 40 40 40 60% vinyl acetate/
ethylene copolymer 40 40 40 40 40 40 40 Al203.3H20 60 60 60 ~ 60 60 60 60 , : : :
Al203.3H20:coated with 1.5% vinyl trime~
thoxyethoxy~silane ~ 60 60 ~ 60 ~ 60i 60 6Q ~ ~ :
Glacial acetic acid treatment of flller ~ YE5 YES~ ~ YE5~ :YES~ YE5: YE5 ;~ YES YE5 Sb205.H20 trea~ment of coated f;ller ~ YES~ ;YE5 ~ YES YES YES
Acetylacetone :treatment of filler ~ YES
- : : :: ~ . . . .
.. - .. ... :.
. -: . .
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- 3~ -TABLE VI
.
% WEIGHT UPTAKE AFTER IMMERSION IN WATER AT 90C FOR
EXAMPLE _ _ ~ __ A 7~.1 19.5 B . 7.7 la.3 C 4.5 ~.8 D 2.0 - 4.3 .
E . 4.8 6.5 F . 1.. 3. 2.5 .
~ - 20.~ 14.2 H ~ 21.9 ~ 21.3 ~ 5 8 ~ ~ a 4 K: : . ~ 5.2 ': : ~ g.4 L ~ - , ~ 1 . 2 ~ ~ 0 . 9 M - ~ 1.9 : 2.2 : - .
._. ~
. ~ .: ~ . :
::
`
.
.:
11 B79g ~
The results shown in Table Vl d~monstrate a dramatic de-crease in water uptake in Examples C, F, I, L and M prod~
u~ed by the antimony (V) complex coati~g, when compared to analogous systems in tùe sbsence oi I complex coating.
.
' ': ~
` ' ' ,~ ` ` `
~, . .. .
.
. . ' ' ' ' .
1 11~7~9~
38 - RK109!128 700 gms. of high surface area (13m2/g) alumina trihydrate were dispersed in 7 litres of:-(i) Triply distilled water.
(ii) Triply di3till~d water to which 35 grams ofzinc uranyl acetate had been added.
.
and vigorously agitated for 3 hours at 80 ~ 85'C. The washed ALTH was recovered by ~iltration and washed dried under vacuum and ball milled. This yleIded material with physical properties (e.g~. T.G.A. curve, surface area etc) similar~ to~tho~e~of the stsrting mstsrlal. The~ recovered ~ "~
ALT~ was (aj compounded with 40~ by weight of a 60% vinyl acetate /40% ethylene copolymer as described in Example 1, (c)~coated; with 5% acrylic acid and 10% antimony pentoxide .
monohydrate before compounding with 40% by weight 60% vinyl acetate/40S sthylens copolymer or (b) ;coated only with 10%
antimony pentoxide~ before compounding with 40% by weight of a 60% vinyl acetate~40% ethylene copolymer. Table VII shows that~ the~beneflts of ths inventlon are observed even~when using-; ALTH which~ha~ been tr~ated to`remove soluble sodium impurity.
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.
Claims (32)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A water stabilized polymeric composition incorporating a hydrated alumina filler as one component, an effective amount of an antimony V compound as another component, in which one or each of the components is/are coated with a reagent which can chemically react with or physically bond to the surface of the other component.
2. A water stabilized polymeric composition incorporating a hydrated alumina filler as one component and an effective amount of an antimony V compound as another component, in which one or each of the components is/are coated with an acid, a reactive acid derivative, or a complexing or chelating agent.
3. A composition according to claim 2, which comprises 5 to 80% by weight based on the composition of the filler, 0.1 to 60% by weight based on the composition of the antimony V compound and 0,1 to 15% by weight based on the filler of the coating.
4. A composition according to claim 2 or 3, in which the hydrated alumina is alumina trihydrate Al2O3,3H2O.
5. A composition according to claim 2 or 3, in which the antimony V
compound is a hydrated antimony V oxide or a precursor thereof.
compound is a hydrated antimony V oxide or a precursor thereof.
6. A composition according to claim 2 or 3, in which the antimony V
compound is present in an amount of from 0.1 to 10 weight per cent, based on the weight of the composition.
compound is present in an amount of from 0.1 to 10 weight per cent, based on the weight of the composition.
7. A composition according to claim 2 or 3, in which the antimony V
compound is present in an amount of from 10 to 25 weight per cent, based on the weight of the composition.
compound is present in an amount of from 10 to 25 weight per cent, based on the weight of the composition.
8. A composition according to claim 2 or 3, in which the acid is acrylic acid or citric acid.
9. A composition according to claim 2, in which the complexing or chelating agent is a polydentate ligand.
10. A composition according to claim 9, in which the polydentate ligand is a .beta.-polyketonate or an imine derivative thereof.
11. A composition according to claim 2 or 3, in which the amount of reagent(s) employed is from 1 to 10 weight per cent based on the weight of the hydrated alumina.
12. A composition according to claim 2 or 3, in which the hydrated alumina has been pre-treated by washing with water or by treatment with a sodium complex-ing or chelating agent to reduce the total sodium level therein to less than 1000 ppm measured as Na20, based on the weight of the hydrated alumina.
13. A composltion according to claim 2, in which the hydrated alumina has been pre-treated with a sodium complexing or chelating agent and washed to remove water soluble compounds thus formed.
14. A composition according to claim 13, in which the sodium complexing or chelating agent is zinc uranyl acetate.
15. A composition according to claim 2 or 3, which comprises a vinyl ester homo - or copolymer or a (meth)acrylate homo - or copolymer.
16. A composition according to claim 2 or 3, which comprises a polymer blend selected from the group consisting of a vinyl ester homo or copolymer, a (meth)-acrylate homo- or copolymer, a polyalkene an alkene copolymer, a segmented polyether ester copolymer, a silicone elastomer, and an acrylic elastomer.
17. A composition according to claim 2 or 3, which comprises less than 15 weight per cent based on the composition, of halogen atoms.
18. Water stabilised hydrated alumina which includes an effective amount of an antimony V compound and in which one or each of the hydrated alumina and the antimony v compound components is/are coated with a reagent which can chemically react with or physically bond to the surface of the other component.
19. water stabilised hydrated alumina according to claim 18, in which the or each reagent is an acid, a reactive acid derivative, or a complexing or chelating agent.
20. Water stabilised hydrated alumina according to claim 18, in which the hydrated alumina has been pre-treated by washing with water or by treatment with a sodium complexing or-chelating agent to reduce the total sodium level therein to less than 1000 ppm, measured as Na20, based on the weight of the hydrated alumina.
21. A process for producing a water stabilised hydrated alumina in which the hydrated alumina is treated with an effective amount of an antimony V
compound and wherein one or each of the hydrated alumina and the antimony v compound components is/are coated with a reagent which can chemically react with or physically bond to the surface of the other component.
compound and wherein one or each of the hydrated alumina and the antimony v compound components is/are coated with a reagent which can chemically react with or physically bond to the surface of the other component.
22. A process according to claim 21, in which the hydrated alumina and/or the antimony V compound is/are coated with an acid, a reactive acid derivative, or a complexing or chelating agent.
23. A process according to claim 22, in which the acid is acrylic acid or citric acid.
24. A process according to claim 22, in which the complexing or chelating agent is a polydentate ligand.
25. A process according to claim 24, in which the polydentate ligand is a .beta.-polyketonate or an imine derivative thereof,
26. A process according to claim 21, in which the amount of reagent(s) employed is from l to 10 weight per cent based on the weight of the hydrated alumina.
27. A process according to claim 21, in which the hydrated alumina has been pre-treated by washing with water or by treatement with a sodium complexing or chelating agent to reduce the total sodium level therein to less than 1000 ppm measured as Na20, based on the weight of the hydrated alumina.
28. A process according to claim 21, in which the hydrated alumina has been pre-treated with a sodium complexing or chelating agent and washed to remove water soluble compounds thus formed.
29. A process according to claim 28, in which the sodium complexing or chelating agent is zinc uranyl acetate.
30. A polymeric composition incorporating a water stabilised hydrated alumina produced by a process according to claim 21.
31. A water stabilised dimensionally recoverable article comprising a polymeric composition according to claim 2.
32. Electrical equipment incorporating as electrical insulation a polymeric composition according to claim 2.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7938148 | 1979-11-03 | ||
| GB7938148 | 1979-11-03 | ||
| GB8022866 | 1980-07-12 | ||
| GB8022866 | 1980-07-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1167991A true CA1167991A (en) | 1984-05-22 |
Family
ID=26273438
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363754A Expired CA1167991A (en) | 1979-11-03 | 1980-10-31 | Polymeric compositions |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1167991A (en) |
-
1980
- 1980-10-31 CA CA000363754A patent/CA1167991A/en not_active Expired
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