JPH0630203B2 - Polybutylene gel filled cable - Google Patents

Description

Description: BACKGROUND OF THE INVENTION Cables for power, electronic (telephone) transmission, underwater audio cables for oil exploration in the sea and many other applications include:
Since the 1970s, it has been filled with various substances for protection against ingress of water. Inundation occurs when water penetrates into localized holes in the cable sheath and often flows hundreds of feet or so free, as long as the physical processes for spreading and transporting the water permit. This not only unbalances the capacity of the transmission cable line, but introduces more potential points of corrosion in proportion to the length of the moist wire. The useful life of a wire immersed in water is clearly shorter than that of a dry wire.

A widely used solution is to prevent the ingress of water simply by filling the voids in the cable with a water-insoluble filling material that wraps around the cable components. However, while this physical function of cable filling material is simple, the choice of material is not so straightforward. Among the many important issues to consider for the materials used in this application are the material's hydrophobicity, low temperature properties, high temperature flow properties, maximum usable temperature of the coating material (“upper temperature limit”), processing. Characteristics, handling characteristics,
Dielectric, toxic and costly.

Widely used materials that meet most of these criteria are September 21, 1971 and 1973, respectively.
U.S. Pat. No. 3,607,48 published February 20, 2010
7 and 3,717,716. These materials are essentially petroleum jellies mixed with a polymer, usually polyethylene, to impart consistency and prevent flow at warm temperatures below the upper temperature limit of use.

Similar hydrophobic coating materials have been proposed for filling splice caps. For example, U.S. Pat. No. 3,879,575, published Apr. 22, 1975, gels with styrene-isoprene-styrene copolymers, also with polyethylene added to impart consistency and reduce sagging. A mixture of liquefied low viscosity oil is noted.

U.S. Pat. No. 4,259,540 discloses styrene-ethylene-in order to allow the cable jacket material to meet the functional requirements of the cable and to provide good handling properties that petroleum jelly materials do not have. Butylene-styrene-block copolymer, polyethylene and up to 5
Disclosed is the use of paraffinic or naphthenic oils containing% aromatic oils.

However, all of these above coating materials must be heated during the filling operation to a temperature above the material's maximum service temperature. The upper service temperature limit for a material is the temperature above which the material cannot be used in the cable. Thus, filling of most materials requires a time consuming step to heat the coating material to a consistency that can be pumped for filling. There is a long-felt need for coating materials that can be processed into cables at temperatures well below the "upper temperature limit" of the coating material while meeting the requirements of other filler materials. Conventionally used coating materials have been used to reduce the viscosity of the fluid to a sufficient extent to allow the filling of the cable to a temperature well above the melting point of the material (ie the maximum temperature of use). Needed to be heated. This heating requires a lot of energy and can damage some of the electrical components in the cable. It also precludes the use of cable component materials that have advantageous properties but cannot withstand the high filling temperatures of these coating materials.

Moreover, there has long been a desire for coating materials that are thermally reversible. This means that the coating material can be removed and replaced any number of times below the temperature that would damage the cable during maintenance. The thermally reversible coating material can be heated to a liquid state many times and then cooled to a gel state without degrading the properties of the filling material or cable components. This is particularly true of underwater audio cable, which is generally not permanently equipped, but where the use of such inventions is supreme.

SUMMARY OF THE INVENTION The present invention can be heated to a liquid state and cooled to a gel state any number of times below the temperature that damages the cable, thereby removing and replacing the gel during maintenance. Includes slowly moldable, thermally reversible gels such as The gel is slowly moldable, such that the viscosity of the clear liquid increases over hours to days leading to the formation of a gel. This is the time during which the cable must be filled before the gel material becomes too viscous to flow or must be removed during maintenance.

Gels are based on light hydrocarbon process oils and isotactic butene-1 polymers or butene-1 copolymers. The filler material or gel coating compound comprises from about 2% to about 8% by weight butene-1 polymer or copolymer, wherein the butene-1 polymer or copolymer is from about 0% to about weight%. From about 0% by weight to about 10% by weight styrene containing about 10% C _{2 to} C ₅ comonomer.
It comprises an ethylene-butylene-styrene block copolymer and a naphthenic or paraffinic oil having an aromatic content of from about 82% by weight to about 98% by weight up to 25% by weight. The coating compound is preferably about 6% by weight butene-1 polymer or copolymer, wherein the butene-1 polymer or copolymer preferably contains about 6% by weight comonomer, preferably by weight. About 5
% S-EB-S block copolymer, and preferably a naphthenic or paraffinic oil, preferably having an aromatic content of about 89% by weight, preferably about 15% by weight. It is preferable C ₂ -C ₅ comonomer is ethylene monomers.

The invention also includes a cable or other conduit containing the above-described coating compound that requires protection against water.

DETAILED DESCRIPTION OF THE INVENTION The coating compound or gel of the present invention has the following properties: 1) the material is a clear low viscosity fluid above the gel temperature; 2) after cooling to room temperature the viscosity is hours to days. The material becomes too viscous and does not flow; it becomes translucent as it forms a gel; 4) the gel can remove and replace it during maintenance As such, it is thermally reversible below the temperature at which it damages the gable; 5) the melting temperature of the gel, the molding temperature and the molding time are determined by the copolymerization of the polybutylene polymer component or homopolymer in the base polymer. Can be controlled by the selection and concentration of

6) The gel is hydrophobic and protects the cable from water leaks.

Gels are based on light hydrocarbon process oils and isotactic butene-1 polymers or butene-1 copolymers. Because of their compatibility with oil and crystallinity,
Isotactic polymers or copolymers dissolve in oil above the melting temperature of the polymer. Once dissolved, these polymers show very slow recrystallization and formation of a gel network from solution as the temperature is reduced, at about 24 to 24% at temperatures significantly below the melting temperature of the gel. 48
Allow the material to remain fluid over time.
Eventually, polymeric polybutylene crystallites form and become network-bonded, forming a translucent gel.

The presence of ethylene comonomers has been found to reduce both the melting point of the gel and the rate of crystallization.

Example 1 Isotactic butene-1 homopolymer was treated with H 2 at 120 ° C. to give a solution containing 6% polymer.
Dissolved in V1 100N oil. As the solution temperature was lowered, the viscosity began to rise sharply at about 40 ° C. (this temperature is the minimum fill temperature) and continued to rise until a firm gel was formed within 1 hour of reaching room temperature. The resulting gel had a melting point of about 80 ° C.

Example 2 6% DP8010 isotactic butene-1 containing 5.7% by weight ethylene comonomer was added to HV1.
Dissolved in 100N oil. When the solution was cooled from the temperature required for dissolution, 128 ° C, the viscosity began to rise at about 30 ° C. Within 24-48 hours after the start of the cooling step, the solution material formed a viscous, usable gel. The resulting gel had a melting point of 55-60 ° C.

Example 3 The polybutene-1 gel containing the ethylenic comonomer of Example 2 is loaded into a suitable cable within 24-48 hours after initial cooling from solution. The cable is ready for use within about 12 hours after such filling.

C_Two~ C₅It is a comonomer and the range is from 2 to 8%.
Is possible, but it must be about 6% ethylene comonomer.
The addition of comonomer, which is preferable to
It is clear that it has a dramatic effect. Besides, 1
Many hydrocarbon fluids with molecular weights above 50
Sotactic butene-1 homopolymers and copolymers
It may be gelled. For example, 16% fragrance
HV1 100N oil with a family content is used. Che
Obtained from Ruoil, Houston, Texas
A shelf containing about 24% aromatic content
Rex 131 can also be used as a suitable oil
Available and available from Sun Oil
Thumper that can 120LW is less than 5% aromatic
Have content.

Blends of microcrystalline wax and polybutylene, such as Shell Max 500 available from Shell Oil Company, Houston Texas, produce a somewhat faster, stiffer gel than gels according to the invention.
It is noted that it produces a more opaque gel.

In addition, Shell Oil Company from Houston Texas
Available, Clayton G thermoplastic rubber
About 0% by weight to about 10% by weight is added during gel formation.
Increase the strength and transparency of the gel with a slight decrease in
It

Referring to FIG. 1, it can be seen that the coating compound or gel according to the invention is filled at 55-60 ° C., well below the use temperature of polybutene-1 of 80 ° C. The solid gel formation temperature is 30 ° C, thus the filling range is from 80 ° C to 30 ° C.
It is in the range of ° C. If a filler material consisting of wax or rubber is used, such filler material must be filled at a temperature higher than 80 ° C., which is the working temperature of polybutene-1, as shown in FIG. This, of course, requires additional heating steps that are time consuming and costly prior to filling, as well as reheating each time it is necessary to refill the cable due to leaks or other problems. If necessary, tighten. The use of such materials also precludes the use of cable components that are sensitive to temperatures above 80 ° C.

The present invention not only provides for slow moldability, which allows sufficient time to fill the cable without additional heating steps, but the cable later breaks to remove gel material and / or re-insert into the cable. If it has to be filled, it must be thermally reversible so that it can be heated to form a solution and cooled to the filling temperature many times without any loss of the desired filling properties of the gel material. It also includes a gel material that also has.

Various additional modifications and extensions of the invention, such as to various cables or none at all, will be apparent to those skilled in the art. Basically, all changes and modifications that rely on teachings such as to improve the invention should be properly considered within the spirit and scope of the invention.

[Brief description of drawings]

FIG. 1 shows the maximum temperature of use of the polybutylene gel and the temperature required for filling conventional coating materials such as wax, rubber, etc. and the temperature at which the coating gel formulation of the present invention can be filled. It is a graph which shows a relationship.

Claims (7)

[Claims] 1. About 2 percent by weight to about 8 percent by weight butene-1 polymer or copolymer, wherein the butene-1 polymer or copolymer is about 0 percent by weight to about 10 percent by weight. containing the percentage of C ₂ -C ₅ comonomer; about 10 percent at about 0 percent to weight by weight styrene - ethylene - butylene - about 98 to about 82% to by weight styrene block copolymer and the weight
A naphthenic or paraffinic oil, wherein the oil has an aromatic content of from about 0 percent by weight to about 25 percent by weight of polybutylene at a temperature of use or slower for filling cables. Moldable, thermally reversible coating gel compound. 2. The coating compound comprises from about 4 percent by weight to about 7 percent by weight butene-1 polymer or copolymer, wherein the butene-1 polymer or copolymer comprises from about 3 percent by weight to about 3 percent by weight. About 8 percent by weight of the C ₂
C ₅ comonomer; about 4% to about 6% by weight of the styrene-ethylene-butylene-styrene block copolymer, and about 87% to about 96% by weight of the naphthenic or paraffinic. The coating compound of claim 1 comprising a base oil, wherein the oil has an aromatic content of from about 5 percent by weight to about 25 percent by weight. 3. The coating compound comprises about 6 percent by weight butene-1 polymer or copolymer, wherein the butene-polymer.
One polymer or copolymer comprises about 6 percent by weight of the C ₂
Containing -C ₅ comonomer; weight about 5% of the styrene - ethylene - butylene - styrene block copolymer, and weight about 89% of the naphthenic or paraffinic oils, wherein the oil is about in weight A coating compound according to claim 1 having an aromatic content of 15 percent. 4. A cable body containing a slowly moldable, thermally reversible coating compound, wherein the coating compound comprises from about 2 percent by weight to about 8 percent by weight butene-1 polymer or copolymer. Wherein the butene-1 polymer or copolymer contains from about 0 percent by weight to about 10 percent by weight C _{2 to} C ₅ comonomer, and from about 92 percent by weight to about 98 percent by weight naphthene. A system or octene-based oil, wherein the oil has an aromatic content of from about 0 percent by weight to about 25 percent by weight and can be used for low temperature filling without sacrificing use temperature. And a cable that can be easily repaired. 5. The cable of claim 4 which can contain from about 0 weight percent to about 10 weight percent styrene-ethylene-butylene-styrene block copolymer. 6. The coating compound comprises from about 4 percent by weight to about 7 percent by weight butene-1 polymer or copolymer, wherein the butene-1 polymer or copolymer comprises from about 3 percent by weight to about 3 percent by weight. About 8 percent by weight of the C ₂
C ₅ comonomer; about 4 percent to about 6 percent by weight styrene-ethylene-butylene-styrene block copolymer, and about 87 percent to about 92 percent by weight of the naphthenic or paraffinic system. The cable of claim 4 comprising an oil, wherein the oil has an aromatic content of from about 5 percent by weight to about 25 percent by weight. 7. The coating compound comprises about 6 percent by weight butene-1 polymer or copolymer, wherein the butene-1 polymer or copolymer comprises about 6 percent by weight C _2.
Containing -C ₅ comonomer; weight about 5% of the styrene - ethylene - butylene - styrene block copolymer, and weight about 89% said naphthenic or paraffinic oil, wherein the oil is about in weight Claim 4 having an aromatics content of 15 percent.
Cable described in section.