DE1669732A1 - Electrically insulating materials and structures made from them - Google Patents

Description

British Insulated Callender's Gables Limited 21 Bloomsbury Street, London «'/.C / EIGLAND

and

Oo M.Υ / "Laboratories Limited

Preston Hew Road, Blackpool, Lancashire / SlIG-LAiTD

Electrically insulating materials and structures made from them.

Priority : British patent application Fo. 47979/66 of October 26, 1966

The invention relates to cold-curing binary synthetic "tables Harzraischun ^ en, that is, Harz with so hung from of a kind which comprises two ingredients mixed together and then converted into a liquid or semi-liquid state and after mixing to a hard infusible mass without Use of t / ärnie harden. The invention relates to also facilities and apparatus as well as ropes made therefrom which are enveloped, filled and / or filled with these mixtures are impregnated.

The synthetic fiarzinischungeri which are previously in common use for such purposes, epoxy resins and i ^J ol yuretha.nharze. Both have disadvantages. The epoxy resin mixtures

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generally have too high a viscosity to to fully ensure a satisfactory impregnation and require up to 48 hours of time to complete o In addition, the persons handling them must take special precautionary measures taken to protect against skin damage caused by these products * The polyurethane resins have a sufficiently low viscosity to achieve satisfactory impregnation to enable, but do not have sufficient resistance to water *, one can therefore do not rely on them when forming enclosures for electrical devices or other objects wants to know where the exclusion of moisture is essential, or when it comes to impregnation of is porous objects, which are required to be completely impermeable to moisture, as well as such porous objects are wraps of textiles around electrical cables and cable connections ο

The invention provides an improved binary, curable, synthetic resin mixture, a process for the manufacture thereof, and improved encased m & L filled and / or impregnated articles, the

ο improved resin mixture is non-toxic and in to.

^ Low viscosity when freshly mixed - ^. in comparison with epoxy resin mixtures and in oo the hardened state essentially impermeable

* ~ against water and essentially invulnerable by Bacterial action and soil acids is.

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The resin mixture according to the invention comprises two syrups "A" and "B".

Syrup "A" is a stabilized syrup consisting essentially of a solution of a methyl methacrylate polymer in methyl methacrylate monomer containing sufficient amine promoter to promote a catalytic polymerization reaction when a suitable catalyst is added to the syrup. The solution is prepared by adding a polymer or liquid polymer of methyl methacrylate in spherical form to diethyl methacrylate monomer in such proportions that the proportions of monomeric ethyl methacrylate for polymerizing methyl methacrylate are within the range of 2.5-3.5 parts by weight to one part by weight. The polymeric methyl methacrylate component is preferably present entirely as a methyl ethacrylate homopolymer, but it is also possible to use an ethyl methacrylate copolymer or a mixture of the homopolymer and the mixed polymer which has essentially the same properties as the homopolymer. The "liso" olymer or homopolymer / mixed polymer mixture is preferably not contained or comes from constituents which contain more than 10% by weight of monomers other than methyl methacrylate. The amount of amine promoter added to the syrup will normally be within the range of 0.25-0.5% by weight based on the weight of the solution, with the preferred promoter being diethyl-p-toluidine

109324/1894 - 4 -

1689732

Syrup "B" consists essentially of one or more plasticizers and a catalyst, preferably a dispersion of an organic peroxide, such as, for example, benzoyl peroxide in a plasticizer, and preferably a phthalate, such as, for example, dimethyl phthalate.

Syrup "A" is preferably stabilized up to 100 parts per million, based on the I ¹ IUssigkeitsgeiia2t on a stabilizer for the solution, for example 2,4-methyl-6-te.rtiärbutylphenol, hydroquinone or the methyl ether of hydroquinone.

To the card of the finished polymerize system through To increase crosslinking, a difunctional monomer can be incorporated into Syrup "A". The preferred one The monomer is ethylene glycol dimethacrylate, but longer ethylene-chain dimethacrylates, e.g. triethylene glycol dimethacrylate or tetraethylene glycol dimethaerylate can be used. Instead or in addition divinylbenzene and / or allyl diglycol carbonate can be used for this purpose.

Other plasticizers preferred for Syrup "B" are cyclohexyl phthalate and diisobutyl phthalate. Syrup "B" can also contain one or more extenders and the preferred extender is a chlorinated paraffin wax, a typical example of such a wax being that sold under the trade name "Cereclor".

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The invention also includes an electrical cable and connections or terminations for electrical cables, which comprise at least one insulating mass of synthetic resin, which is made by mixing τοπ syrup "A" and ¹¹ B. "A cavity is made on such a connection or termination or sheathing, which directly or indirectly surrounds a connection point or termination of a cable core or cable cores, is filled with a mixture of the syrup "A" and the syrup "3", or is first at least partially filled with pieces of an essentially non-porous material, which does not react with the resin but to which the resin adheres when it hardens, and then all or substantially all of the remaining space in the cavity or envelope is filled with the mixture of syrups "A" and "B" Resin compounds for use in cables, cable connections or cable terminations can also be made from the iiarz will. The resin mixtures formed by mixing the two syrups are particularly suitable as impregnating agents for fibrous structures which form parts of electrical cables or connections or interlocks therefor, and the invention includes a method of building such structures by applying fibrous material and either simultaneous or subsequent impregnation with the syrup mixture.

Yes ^{1 For} some applications of the improved erfindungsgesiäsaen iiarzmischuny can ea for the mixture of the

109824/1894

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Syrups "A" and "B" need to be higher
To have initial viscosity. In such cases
the syrup "B" can be thickened by a polyvinyl chloride / maleic anhydride or a polyvinyl acetate / maleic anhydride polymer »The incorporation of such a polymer also increases the adhesion of the polymerized system to polyvinyl chloride compositions»

For some purposes it is advantageous to reduce the flammability of the polymerized resin system, and this becomes advantageous by adding not
volatile and non-toxic chlorinated phosphate compounds to syrup "B" reached. An example of such a chlorinated phosphate compound is Riis-2> E-dichloropropyl phosphate.

The invention will be further illustrated by a description of examples of the binary resin mixture and by a description of electrical cables, cable connections and cable terminations into which the binary resin mixture is incorporated,

example 1

This is an example of a syrup "A" and a syrup ¹¹ B "compatible therewith, suitable for preparing a mixture for use in cable connection purposes. The composition of the syrups is as follows

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109824/1894

isyrup "A"

40 kg 20th kg 2 kg

Methyl methacrylate polymer 30 kg

Methyl methacrylate monomer 70 leg

2,4-methyl-6-tert-butylphenol 35 parts per

• η r ρ φ '-j million

Ethylene glycol dimethacrylate 1.5 kg

Syrup "B"

Chlorinated paraffin wax

Cyclohexyl phthalate benzoyl peroxide paste

The syrups "A" and "B" are mixed together in proportions of 2.3 parts by weight of the syrup ¹¹ A "to one part by weight of the syrup" B "to give a solution whose viscosity is sufficiently low (2 minutes from No. 4 Ford Cup one minute after mixing) is to completely impregnate a wrapping of textiles and which cures by itself within an hour.

Example 2

This is an example of a syrup "B" in which a flame retardant is incorporated. The composition of the syrup is the following j

Chlorinated paraffin wax 40 parts by weight tritolyl phosphate 30 "

Tris-2,3-dichloropropyl phosphate 10 " Benzoyl peroxide paste, 2 "

In this example, an additional flame-retardant substance, namely iritolyl phosphate, is also used. Tri-GiEsylphoaphat could also serve as an additive or instead of the tritolyl phosphate

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Examples of electrical cables and cable joints and cable terminations ¹ ^ in which the resin prepared ^ by mixing syrup ¹¹ A "and syrup" B "can be used are as follows

Example 3 »

The mixture of syrup "A" and syrup "B" is made used as a waterproofing agent for wraps of textiles for use in joining, closing and repair of electrical cables »Such windings are preferably built up in situ by application successive layers of the textile material, which consists of organic or inorganic Fibers, and impregnating each layer or any number of groups of layers with the Syrup mixture while the winding is being built up * Instead, the textile material can be impregnated with the syrup mixture immediately before the application of the extile material, or the whole winding can built up dry and then impregnated with the syrup mixture · Such a winding can for example can be used as a seal between a metal or plastic, or natural or synthetic Rubber (as a cable jacket) and a fitting piece, for example a stuffing box, through which the cable passes through the sheathing in situ after the cable has been inserted by means of a suitable * te openings built in the fitting piece · The fitting piece can, for example, be part of a connecting sleeve or Rope of a cable termination

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Example 4 «

A structure similar to that described in Example 3 is built up over the entire length of a connecting sleeve or sheathing for an end closure by applying an overlap made of textile material on a tubular support surrounding the joint and on the adjacent part or parts of the Cable length or cable lengths and impregnation of the textile during its application or afterwards with a Mixture of "A" and "B" syrups »If necessary is then an outer casing made of plastics, which is resistant to the The effect of the syrup mixture and the textiles impregnated with resin are applied over the ζ / anze «

Example 5 »

A structure similar to that of Example 4 is produced by applying the entire textile to the Wrapping and subsequent impregnation with dar Syrup mixture by applying a loose, flexible casing to the textile to be impregnated, introducing the Syrup mixture in the space between the textile mass and The shell and processing of the mixture on a coherent basis Mass by kneading, applied to the outside of the flexible shell. By this impregnation method an outer cover is preferably applied over the loosely flexible cover after completion the kneading treatment, but before the resin is hardened. This procedure can be applied to. Connections or terminations, or on cables, in s: mer position *

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where a repair is effected or a blocking block is created against the passage of gas or water along the cable shall be,

Example 6

The syrup mixture is used to make the barely between a cable connection or a cable termination and the connection sleeve or the terminal box or the Picium between the sinor connecting sleeve or the terminal box and an outer container to be filled.

Example 7

A modification of example 6, in which the space is filled with a mass which comprises an aggregate of solid material embedded in a solidified matrix of the resin composition. The solid foaterial is non-porous and does not react with the synthetic resin mixture, but the mixture sticks to it when it hardens. An example of such a material aggregate is granite chippings. The space is first at least partially filled with the granite chippings or other aggregates, and all or substantially all of the remainder of the space is then filled with the Birup mix O
Example 8

Solid bodies are made from the syrup mixture with or without a fibrous or other puller for use at junctions and fasteners for electric power cables. An example of such a body is a shaped probe end for placement on the end of a Cable core during high voltage test ^ ο /

Specific examples of those in Examples 3 "to mentioned structures are the subject of the following British Patent applications: example

British patent
Sign up Appropriate
German registration 833 787 ' 870 165 - 966 125 1,065,431 - 2 9704/66
and related
Registration 51499/66 48855/65 at the 893 376 B 59863 VIIId / 21c 930 017 B 65832 VIIId / 21c,

109824/1894

Claims (1)

Claims 1. Cold-curing binary resin mixture, comprising swei syrups "A" and ¹¹ B ", which can be mixed with one another and used in liquid or semi-liquid state and harden after mixing to a hard, insoluble mass without the application of heat, characterized in that syrup" A "is a stabilized syrup consisting essentially of a solution of a methyl methacrylate polymer in methyl methacrylate monomer which contains a sufficient amount of an amine promoter to promote the catalytic polymerization reaction when a suitable catalyst is added to the syrup, and the syrup" B "consists of one or more plasticizers and this catalyst. 2. Resin mixture according to claim 1, characterized in that the stabilized syrup consists essentially of a polymer of methyl methacrylate in spherical form in Hethylmethacrylatmonomer within the range of 2.5-3 »5 parts by weight of the monomer to one part by weight of polymer spheres and from 0.25 to 0.5 $> of the amine promoter. 3 Resin mixture according to the preceding claims, characterized in that the amine promoter is dimethyl-p-toluidine _ _13ta 1098 24/189 ώ- · resin mixture make the preceding claims ^ characterized in that syrup "A" is stabilized by up to 100 ropes per million £ hurry, based on the entire fluid volume «- r.alt, aii a stabilizer © 5 · resin mixture according to claim 4 »characterized § Eke η η ~ 7, i β η et that the stabilizer containing 2,4-methyl-6-tertiary utylphenol ^ ^ or hydroquinone · S. Resin mixture according to the preceding claims, characterized in that a difunctional monomer, which can increase the hardness of the final polymerizing system, is added to syrup "A ^u . 7β resin mixture according to claim 6, characterized in that the difunctional monomer ethylene glycol dimethacrylate is· 8. resin mixture according to claim 6, characterized in that the difunctional monomer is a Longer-chain G-glycol methacrylate ala ethylene glycol methacrylate is* 9 »Resin mixture according to claim 7, characterized in that the difunctional monomer divinyl · benzene or allyl diglycol carbonate is «10. Resin mixture according to the preceding claims, daduroh marked that an expander is added to syrup "B" * 11 »Resin smell according to claim 10 _f thereby geke η η ^ siohnet» daae the expander hloriertee Pa · »ÄÄ tit» 10 9 8 2 4 / ^T ; 9 4 ~ 14 ~ 12. Resin mixture according to the preceding claims, characterized in that syrup ¹¹ B "is thickened by the addition of a polyvinyl chloride / maleic anhydride or a polyvinyl acetate / maleic anhydride polymer 13. Resin mixture according to the preceding claims, characterized in that syrup "B ^{fl" contains} a sufficient amount of a non-toxic chlorinated phosphate compound to reduce the flammability of the polymerized resin system. 14 · Resin mixture according to the preceding claims, characterized in that the catalyst is an organic peroxide. 15. Resin mixture according to claim 14, characterized in that that the catalyst is benzoyl peroxide. 16o resin mixture according to the preceding claims, characterized in that the calibrator is a phthalate. 17o resin composition according to claim 16, characterized characterized geke nn that the plasticizer dimethyl- cyclohexyl or diisobutyl phthalate is. 1.8 «, synthetic resin body, characterized in that it is produced by mixing a syrup" A "and a syrup" B ¹¹ according to one of the preceding claims and allowing the mixture to harden . - 15 - 109824/1894 166973? 19 «Electrical cable structure or a connection or ■ termination for an electrical cable, comprising at least one insulating synthetic resin body _t characterized in that the resin of the body is obtained by mixing the two syrups ¹¹ A" and "B", as in any one of the preceding claims 1 -17 is claimed. 20. Connection or binding for an electrical Cable, comprising a cavity or an enclosure, -.Each directly or indirectly a connection point or an end of a cable core or a plurality of cable cores filled with a synthetic resin thereby characterized that this resin is characterized by Mix the two syrups "A" and "B" as in one of the Claims 1-17 claimed is made. 21. Connection or binding according to claim 20, characterized in that the enclosure or cavity is at least partially filled with pieces of solid, essentially non-porous material that does not react with the resin, but does to which the resin adheres as it hardens and all or substantially all of the remainder of the space is filled in the cavity or enclosure with the resin originating from the mixture of the syrups. 22. An electrical cable structure or a junction or termination for an electrical cable, comprising at least one insulating body, formed duroh Impregnation of a fibrous agent with a cold-setting resin, characterized in that 109824/1894 - 16 - that the resin is prepared by mixing two syrups "A" and ¹¹ B "as claimed in any one of the preceding claims 1-17, 10982A / 1894