JPS62115047A - Tree delaying high voltage composition and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a novel trily consisting of a polymer component and an oligomer copolymer used as an insulating material for electrical conductors.
(trvg) Relating to a retarding composition.

The reduction in electrical insulation properties of polymeric dielectric materials is due to a number of factors, one of which is known as the Tory phenomenon. It is generally said that there are three causes of trifle, one of which is
One is water ingress into the dielectric material, the other is electrical overload, and the other is contamination by external substances such as metal particles and voids. These are called water trees, electrical trees, and electrochemical trees, respectively. The tree phenomenon is caused by the fracture of the polymeric dielectric material, and as the fracture progresses, so does the damage to the dielectric material through the dielectric material in a tree-like path. The tri-phenomenon usually progresses slowly and takes many years before the polymer composition reaches catastrophic failure and is no longer useful as an electrical insulator.

Various additives have been proposed in the past to form tri-retardant compositions in addition to polymeric dielectric materials. Ashcraft et al., U.S. Pat. No. 4,144,202, discloses certain silane compounds that suppress water tree phenomena in ethylene polymers, and McMahon, U.S. Pat. No. 4,206,6
No. 20 discloses the use of alcohols having from 6 to 24 carbon atoms to impart electrical growth resistance to compositions used as insulation for high voltage chamber capsules. Above 2
The subject U.S. patent describes in some detail water trees and electrical trees in polymeric compositions, and also describes tree-retarding compositions in polymers and polymeric dielectric materials suitable for use as dielectric materials. The book describes many known examples disclosing proposals for solving this problem, including methods of adding a conductive material and forming a film on a conductive material.

U.S. Pat. No. 4,499.013 to Barlow discloses certain fatty acid, ester, and alcohol cast conductors useful as electrically tri- and water-resistant compounds in polymeric compositions; and Mullinger, U.S. Pat. No. 4,536,530, disclose organophosphorus compounds useful as water-resistant additives for polymeric compositions.

Pages 68 to 77 of Development of Materials for the Heli High Performance XLPE Cables, presented at the Wire Association Meeting held in Baltimore, Maryland, in November 1984, were published by Otani et al. U.S. Pat. No. 3,929,72 discloses certain ethylene copolymers added to cross-linked polyethylene as additives to reduce the amount of ethylene.
No. 4 discloses the preparation of crosslinkable polyethylene compositions with improved aging properties obtained by first dispersing an antioxidant in an ethylene vinyl acetate copolymer and then mixing this with polyethylene.

The present invention provides an oligomer copolymer (cooligomer) of at least one α-olefin having up to about 8 carbon atoms and at least one α-unsaturated ester having up to about 10 carbon atoms, which has a Brookfield viscosity of about 100 cp (100 cp°C). The present invention relates to a tri-retardant composition having a viscosity range up to about 500 with a melt index according to the AsTM D1238 Condition A method.

The Brutzfield viscosity is as shown in table ■! 1c4-1
Measurements are made on a standard RTV Brookfield viscometer with a thermocell attachment using an 8 spindle and viscosity dependent speed.

The oligomer is integrated with a polymeric material used as an insulating material for electrically conductive materials.

The present invention also relates to a method of making tri-retarding compositions by combining the oligomeric copolymers and polymeric materials described above.

As mentioned above, tri-retarding compositions are known to those skilled in the art and are used in combination with polymeric dielectric materials to prevent or minimize tri-phenomena such as water-tri and or electrical tri-. It is something.

The present invention relates to tri-retarding compositions comprising a polymeric material and an oligomeric copolymer of at least one alpha-olefin having up to about 8 carbon atoms and at least one alpha-unsaturated ester having up to about 10 carbon atoms. .

Although the term copolymer is often used to refer only to polymers obtained by polymerizing two monomers together, in the present invention it refers to polymers obtained by copolymerizing two or more monomers together, e.g. 2.3.4 or more. A composition based on the monomers of the following is polymerized into a single polymeric composition. The copolymer in the present invention includes a random copolymer,
The copolymer may be of any known form such as graft copolymer, block copolymer, star copolymer, etc.

The α-olefin component of copolymer A can have up to about 8 carbon atoms, as described above. Any α-olefin, either aliphatic or side-chain olefin, having from 2 to about 8 carbon atoms may be used. Examples include ethylene, propylene, isobutylene, 1-pentene, 1-hexene, 1
-H-1-tene, 1-octene, etc., their depleted isomers, and mixtures thereof. Preferred α-olefin components are ethylene, propylene or mixtures thereof;
The preferred alpha-olefin component may optionally contain alpha-olefins having from 4 to about 8 carbon atoms.

As mentioned above, the α-unsaturated ester that can be used is about 1
Those having up to 0 carbon atoms include various vinyl and acrylic esters and their known equivalents. Examples of vinyl esters include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, and the like. Examples of acrylic esters include various esters such as acrylic acid, methacrylic acid, ethacrylic acid, such as ethyl acrylate, ethyl methacrylate, methyl acrylate, methyl methacrylate, n-butyl acrylate,
n-butyl ethacrylate, n-butyl methacrylate, 5-pentyl acrylate, n-pentyl acrylate, de-hexyl acrylate, 5-hexyl methacrylate, 5-hexyl methacrylate and various isomers thereof, known There are equivalents and mixtures thereof.

The α-unsaturated ester used in the oligomer is about 10
It is present in an amount of from about 90% by weight, preferably from about 30 to about 80%.

Examples of oligomers that may be used include ethylene vinyl acetate copolymers having a vinyl acetate content t' of from about 10 to about 90 weight percent, preferably from about 30 to about 80. Particularly preferred oligomers have a vinyl acetate content of about 4 ON. ．． 5
(It has a viscosity of about 800 cpa at 140°C as measured on an RVT Brookfield viscometer with a thermocell attachment at 3 rpm using a 11'4-18 spindle.

% in oligomers of ethylene and butyl acrylate
-butyl acrylate contents of from about 10 to about 90% by weight, particularly from about 25 to about 75% by weight, may also be advantageously used.

A terpolymer of isobutylene, ethylene and an α-unsaturated ester such as vinyl acetate or exo-butyl acrylate, the isobutylene content in the polymer being from about 0.5 to
About 10% by weight, especially about 1 to about 5% by weight, may also be preferably used.

The alpha-unsaturated ester used in the terpolymer ranges from about 1% to about 50% by weight, particularly from about 10% to about 40% by weight.
(preferable)

Approximately 5% by weight of the total composition of ethylene propylene rubber (CEPR) i.e. oligomers, polymer components and EPH.
Hereinafter, especially by adding about 2 to about 4% by weight,
and/or a synergistic effect in eliminating or minimizing electrical tree phenomena.

Preferably, the EPR is composed of about 40 to about 80% by weight of ethylene and the balance is propylene, and particularly, one in which the EPR is composed of about 50 to about 75% by weight of ethylene and the balance is propylene. EP
R rubber has a Mooney viscosity (127°C) of about 10 to about 70,
Particularly preferred are those having a molecular weight of about 15 to about 45. A particularly preferred EPR rubber has an ethylene content of about 65% by weight, the balance being propylene, and a Mooney viscosity (at 127°C) of about 20%.
belongs to.

EPR is used when the polymeric material in the composition is other than EPR.

The oligomer is combined with the polymeric component to form a composition in which the total amount of alpha-unsaturated ester in the composition ranges from about 0.2 to about 5% by weight, particularly from about 0.5 to about 1.7N. It is preferred that the amount of α-unsaturated ester in the composition does not exceed an amount to maintain sufficient electrical properties of the composition.

Generally, polymeric materials suitable for the practice of this invention are normally solid synthetic organic thermoplastics. Examples include polyolefins, their copolymers, vinyl polymers, olefin-
These include vinyl copolymers, olefin-allyl copolymers, polyamides, acrylic polymers, polystyrenes, cellulosic polymers, polyesters, and polyfluorocarbons.

Polyolefins include normally solid olefins, particularly polymers of mono-alpha-olefins having from about 2 to about 6 carbon atoms, such as polyethylene, polypropylene, polybutene, polyisobutylene, poly(4-menalupentene).
etc. Preferred polyolefins are polyethylene and polypropylene. Polyethylene is particularly preferred. These polyethylenes include linear low density polyethylene, high density polyethylene and low density polyethylene. A particularly preferred polyethylene is #731 sold by National Daytailers and Chemical Corporation.
0 grade low density polyethylene.

Ethylene and fiber 1. Copolymers of ethylene and other intercopolymerizable compounds such as pentene-11 styrene may also be used. Typically, the copolymer contains about 50 tS or more of ethylene. Ethylene-propylene rubber (EP
R) and ethylene-propylene-diene monomer (HD
Other copolymers such as PM) may also be used.

Examples of preferred vinyl polymers include polyvinyl chloride, polyvinyl acetate, vinyl chloride/vinyl acetate copolymers, polyvinyl alcohol, and polyvinyl acetal.

Examples of preferred olefin-vinyl copolymers include ethylene-vinyl acetate, ethylene-vinyl propionate, ethylene-vinyl isobutyrate, ethylene-vinyl alcohol,
Examples include ethylene-methyl acrylate, ethylene-ethyl acrylate, and ethylene-ethyl methacrylate.

Generally, ethylene is a copolymer of at least about 2531E
ttst'' configuration.

Examples of olefin-allyl copolymers include ethylene-allylbenzene, ethylene-allyl ether, ethylene-acrolein, and the like.

If it is desired to use a crosslinkable polymer composition, known crosslinking means may be used, such as chemical means such as peroxide crosslinking, electron accelerators, high energy radiation such as gamma rays, X-rays, microwaves, etc. can be used. The basic means of crosslinking polymers are well known to those skilled in the art and will not be described in detail.

Commonly used crosslinking agents such as organic peroxides are preferably used. Examples of typical organic peroxide free radical generators include dicumyl peroxide, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, and sheet t.
-Fylveroxide, benzoyl peroxide, α
, α'-bis(t-butylperoxy)diisopropylbenzene, etc., which are disclosed in U.S. Pat. No. 3,287,3.
This is also exemplified in No. 12. The amount of organic peroxide, if used, is about 0.5 to 5.0 phr, or about 0.5 to 10 phr, preferably 3 to 6 phr, based on the total composition.

Other tri-retarders such as silanes, stannate, titanate, phosphorus compounds, etc. may also be used in combination with the oligomers of the present invention.

The situation is from about 1 to about 95% by weight of the oligomer.

Examples of tri-retarders that may be used in combination with the oligomers of the present invention are U.S. Pat.
No. 57, No. 4,400°429, No. 4,483.954, No. 4,514.535, No. 4.536.530 V
It is described in detail.

Other additives of small leaves may also be used in appropriate amounts. Common antioxidants such as hindered phenol and polyquinoline are also used.

What other ingredients can be added? IJ includes plasticizers, dyes, pigments, heat and light stabilizers, antistatic agents, and the like.

The compositions of the present invention are typically unfilled polymeric compositions. By "unfilled" we mean compositions having a typical polymer filler content of 10 parts or less. In some applications, the unfilled composition does not contain any filler. The compositions of the invention therefore contain 0-10% filler. However, when using polymers such as ethylene-propylene rubber (CEPR) and ethylene-propylene-diene monomer (EPDM), the
About 30% filler is typically used. This invention #1 composition is also included in the present invention. Therefore, in the production of the composition of the present invention, fillers such as mineral fillers may be used within the above range. However, it is particularly preferred for certain applications that these compositions also contain no fillers.

The polymer composition of the present invention can be made by mixing the various components described above. When the composition of the present invention is prepared by mixing an organic compound (oligomer) and a polymer component, the organic compound and the polymer component are uniformly dispersed in each other. The order and method of mixing is not critical, but if peroxide mixture is used, the temperature from the time of its addition should be below about 130°C to prevent pre-crosslinking of the composition. However, this precaution itself is well known.

Mixing of the components can be carried out using a variety of equipment such as multi-roll mills, screw mills, continuous mixers, mixing extruders, Banbury mixers, and the like.

After extrusion onto a wire, cable, or other substrate, the crosslinkable composition is vulcanized at temperatures above about 180° C. according to conventional vulcanization methods.

Does the composition of the present invention have an inhibitory effect on water retention? It can be evaluated using

Electrical tree test is DNCVC Double Nee
Performed using the dleCharastarie Volta (H) method ASTM D 3756-79.

The water tree test is carried out using a method similar to that described in U.S. Pat. No. 4,144,202. Compression molded disks of approximately 150 diameters with 10 conical indentations were made for each composition. The disk geometry and indentation dimensions are substantially the same as shown in US Pat. No. 4,144,202. Spray silver paint on the bottom of the disk to use as a ground electrode. Attach a 6 inch length of acrylic tubing to the top surface forming the test cell. 0. Pour approximately 150 di of OIJ/sodium chloride solution into the cell to remove any air bubbles that may form on the surface of the sample. Next, the platinum wire ring was immersed in the t-\Il solution and heated at 5KHz, 5
KV O) 1! Connect to the source. The sample is energized for 24 hours and then removed from the test cell and washed with distilled water. Cut 10 indentations from the disc and color it so that the water tree shows rainbows. After obtaining a small piece with a microtome, examine it with a microscope bag (200x magnification) to measure the thickness of the tree. Typically four disks are made for each sample and the average tree size is calculated from the 400 individual measurements. In the evaluation of different tri-retardants, tri-
The relative tree size is determined by comparison to the average tree size obtained for standard high voltage insulation without retardant.

Next, examples will be shown.

Example 1-A mixture of 30° low density polyethylene (#A310) and 0 oligomers was prepared. The molecular weight of the oligomer is indicated by Brookfield viscosity, melt index (Cur) or melt flow rate (CMFR). The oligomers are based on ethylene, alpha-unsaturated esters and optional isobutylene.

The oligomers, which are liquid at room temperature, were kneaded with polyethylene in a Banbury mixer and then fed into a twin screw extruder to pelletize and evaluate the electrical trie and/or water trie according to the method described above. The oligomer, which is solid at room temperature, is kneaded directly with polyethylene in a twin-screw extruder,
They were evaluated in the same way.

The results are shown in Table 1.

Table l (continued) 1(f%BA)" 141/, 4-14%BA'
18 2 18VA 19 2 40VA 20 2 49.1 %BA22
2 Vistalon 707 (TM
)23 4 Vistalon 7
t) 7 (7'M) 1 Olipmer of Example 20 24 2 74VA25 2
69.1%BA26 2
40VA27 2 28VA
28 2 28VAVE 636 29 N,A.

#A31U 3Q N, A.

Crosslinked HA 31 (J 7.5MFR203187,8 750cpa 82.5 1033
15 cps 13 U3O Mooney 209.5 (127℃) 20 Mooney 232 (127℃) Micron 315cps 86 15.
7 (80,5) 1000MZ 87 43MI 95 230 11.2 130 15.3 Cloudy Mixture of ethylene vinyl acetate oligomer of Example 14 and ethylene n-butyl acrylate oligomer of Example 15 ■ Spindle number 5C4-18 Sample weight,
9 7.2 Spindle Speed Maximum Range゛ Conversion Rate Centivoise Factor

Claims (1)

Claims: 1. An oligomer copolymer (cooligomer) of at least one α-olefin having about 8 carbon atoms or less and at least one α-unsaturated ester having about 10 carbon atoms or less, which has about 100 cps (140 cps) 1. A tri-retarding composition comprising a polymeric material having a viscosity ranging from a Bruckfield viscosity of 50°C to a melt index of about 500 according to ASTM D 1238 Condition A method. 2. α-olefin whose oligomer is ethylene;
The composition of claim 1, which is a copolymer of at least one α-unsaturated ester selected from vinyl esters and acrylic esters. 3. The composition according to claim 1 or 2, wherein the oligomer contains isobutylene. 4. The α-unsaturated ester is present in the oligomer at a weight level of from about 10 to about 90%.
The composition according to any one of paragraphs. 5. If the polymeric material is not an ethylene-propylene rubber, the tri-retardant composition contains up to about 5% by weight ethylene-propylene rubber.
The composition according to any one of claims 1 to 4, which contains propylene rubber. 6. The composition according to any one of claims 2 to 5, wherein the oligomer is obtained from an α-olefin consisting of ethylene and an α-unsaturated ester consisting of vinyl acetate. 7. α-olefin whose oligomer is ethylene and n
The composition according to any one of claims 2 to 5, which is obtained from an α-unsaturated ester consisting of -butyl acrylate. 8. α-olefin whose oligomer is ethylene;
α-unsaturated ester consisting of vinyl acetate and/or n-butyl acrylate in an amount of about 1 to about 50% by weight of the oligomer
and isobutylene in an amount of about 0.5 to about 10% by weight of the oligomer. 9. The composition according to any one of claims 1 to 8, wherein the polymeric substance is an α-olefin. 10. The composition according to any one of claims 1 to 8, wherein the polymeric material is a thermoplastic resin. 11. The ester of the oligomer is present in the composition at a concentration of about 0.5
Claims 1 to 10 present at ~3% by weight
Compositions as described in Section. 12. The polymeric material has at least one α having about 8 or less carbon atoms.
- an olefin and at least one α- having about 10 or less carbon atoms;
characterized by the addition of an oligomeric copolymer (cooligomer) with an unsaturated ester having a viscosity ranging from a Bruckfield viscosity of about 100 cps (at 140° C.) to a melt index of about 500 according to ASTM D 1238 Condition A method. Method for improving tri-retardation of polymeric materials.