JPH01167350A - Water-tight blend - Google Patents

Abstract

PURPOSE:To obtain the title blend bonding to both of a conductor such as crosslinked PE coated electric wire and insulator, by blending an ethylene-vinyl acetate copolymer with a modified polyolefin based adhesive and trimethyl- dihydroquinoline polymer at a specific ratio. CONSTITUTION:(A) 100 pts.wt. ethylene-vinylacetate copolymer (preferably having 15-45wt.% vinyl acetate copolymer content) is blended with (B) 1-20 pts.wt., preferably 3-10 pts.wt. modified polyolefin based adhesive (preferably consisting of a modified ethylene-vinylacetate copolymer having at least two kind of polar groups among OH, acetoxyl and carboxyl in a molecular chain) and (C) 0.1-20 pts.wt., preferably 3-10 pts.wt. 2,2,4-trimethyl-1,2- dihydroquinoline polymer (preferably having 1.04-1.12 specific gravity and >=70 softening point) to provide the aimed blend.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a watertight mixture, and more specifically, the present invention relates to a watertight mixture, and more specifically, to a watertight mixture, and more specifically, to a watertight mixture, and more particularly, to a watertight mixture, the gap between the stranded conductors and the gap between the stranded conductor and the jacket insulator in an insulated wire coated with cross-linked diethylene, etc. It relates to a watertight mixture that is filled between conductors and insulators and adheres to both conductors and insulators.

[Conventional technology and its problems]

Conventionally, in outdoor electric wires such as overhead insulated wires, in order to prevent water from entering the stranded conductors and prevent deterioration of the conductors due to stress corrosion, gaps between the stranded conductors and the outer sheath between the stranded conductors have been A watertight mixture is filled between the insulator and the insulator. In recent years, high viscosity plastic mixtures have been widely used as watertight mixtures in consideration of workability and the like. However, if the viscosity of the watertight mixture is too high, it is difficult to press-fit it into the stranded conductor, so complicated manufacturing methods are required, such as filling it when the wires are twisted together, and manufacturing equipment is also required. There is a problem with increasing the size. For this reason, some products mix low-molecular-weight polyethylene or polyethylene wax to reduce the melt viscosity at the time of filling so that they can be press-fitted into stranded wire conductors after twisting. has poor adhesion,
In addition, because it has poor rubber elasticity, even if insulated wires manufactured using this mixture are initially watertight, when the wire is bent during overhead wiring, separation occurs between the conductor and the watertight mixture. There was a problem of loss of watertightness. Therefore, we developed an excellent product that has a melt viscosity that can be press-fitted into stranded conductors, has good adhesion to conductors and insulators, and that insulated wires filled with this do not lose watertightness even when bent. Several watertight admixtures have been developed. However, it has been found that insulated wires manufactured using such watertight mixtures have difficulty in peeling when used at low temperatures after being left at high temperatures for a long period of time. In other words, when an insulated wire that has been left for several months in the summer after manufacturing is used in the winter, the adhesion between the conductor and the watertight compound increases, so when the jacket insulation is stripped off, the watertight compound is removed. The material remains on the conductor, making the stripping process inefficient. The purpose of the present invention is to provide watertight compatibility that can be easily press-fitted into a stranded conductor, has good adhesive strength with the conductor and insulator, and does not change the adhesive strength with the conductor even if the wire is left for a long time after manufacturing. It's a place that provides things. [Means for Solving the Problems] The watertight mixture of the present invention contains 1 part by weight of the modified polyolefin adhesive per 100 parts by weight of the ethylene-vinyl acetate copolymer.
~20 parts by weight and 0.1 to 20 parts by weight of 2,2,4-trimethyl-1,2-dihydroquinoline polymer. Ethylene vinyl acetate copolymer (EVA) used in the present invention
Preferably, the vinyl acetate (VA) content is 15 to 45% by weight. The reason is that if the vinyl acetate content is less than 15% by weight, the flexibility of the conductor will be impaired, and if it is more than 45% by weight, the adhesive strength with the insulator will be reduced. . Furthermore, the ethylene vinyl acetate copolymer used in the present invention includes not only one type of ethylene vinyl acetate copolymer alone, but also a mixture of two or more types of ethylene vinyl acetate copolymers having different vinyl acetate contents. . Further, as the ethylene vinyl acetate copolymer, it is desirable that the copolymer has rubber elasticity that can cope with the strain caused even when the electric wire is bent. Furthermore, the modified polyolefin adhesive used in the present invention is one in which functional groups are introduced into various polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers through graft polymerization, etc., to give them adhesive properties with metals and plastics. Synthetic resin. The reason why a modified polyolefin-based adhesive is blended is to increase the adhesive strength of the watertight mixture, and the reason why a modified polyolefin-based adhesive is selected is because it is compatible with ethylene-vinyl acetate copolymer. It has good solubility. Among these, a modified ethylene vinyl acetate copolymer having at least two types of polar groups among hydroxyl group, acetoxyl group, and carboxyl group in the molecular chain is preferable. There is an adhesive (manufactured by Takeda Pharmaceutical Company, Dumilan, Type C) made of a partially saponified ethylene-vinyl acetate copolymer expressed by the formula: X-C)1 X-CH However, X: Contains a COOH group. The blending amount of such modified polyolefin adhesive is 1 to 1 to 100 parts by weight of ethylene vinyl acetate copolymer.
It is 20 parts by weight. If the amount of adhesive is less than 1 part by weight, the adhesion effect will be poor, and if it exceeds 20 parts by weight, the adhesion to the conductor will be too strong, and the watertight mixture will not adhere to the conductor when the insulation/body is removed. remains adhered to. The preferred amount is 3 to 10 parts by weight. In addition to the above-mentioned Dumilan, examples of modified polyolefin adhesives include Atmer (Mitsui Petrochemical Industries Ltd.)
There is a trade name), but when using this, 3 to 10 ffi is used for 100 parts by weight of ethylene vinyl acetate copolymer.
It is preferable to mix a certain amount. The 2,2,4-trimethyl-1,2-dihydroquinoline polymer used in the present invention has a specific gravity of 1.04 to 1°12, a softening point of 70°C or higher, and antigen RD-F.
' (manufactured by Sumitomo Chemical Co., Ltd.), Tsukrak 224 (manufactured by Iriuchi Shinko Co., Ltd.), Nonflex RD (manufactured by Seiko Kagaku Co., Ltd.), Antige RD (manufactured by Kawaguchi Kagaku Co., Ltd.), etc. This 2.2.4-trimethyl-1,2-dihydroquinoline polymer has the function of stably maintaining the adhesive strength between the watertight mixture and the conductor. 2.2.4-) The blending amount of samethyl-1,2-dihydroquinoline polymer is 100% of ethylene vinyl acetate copolymer!
The amount is 0.1 to 20 parts by weight based on the amount of Il. If the blending amount is less than 0.1 part by weight, if an insulated wire manufactured using this watertight mixture is left at a high temperature for a long period of time and then stripped at a low temperature, the watertight mixture will be deposited on the conductor. remains. If the amount is more than 20 parts by weight, the adhesion to the conductor will be poor and the watertightness will be poor. The preferred amount is 3 to 1
It is 0 parts by weight. The melt index of the watertight mixture is 5 to 200.
It is preferable that A material having a melt index of less than 5 is undesirable because it requires excessive pressure to fill the stranded wire conductor and increases the size of manufacturing equipment. on the other hand,
Insulated wires manufactured using watertight mixtures with a melt index of over 200 not only have the risk of softening or dripping when used at high temperatures, but also have the risk of tensile strength at the conductor connections made by sleeves. This is not preferable because it lowers the temperature. In order to bring the melt index of the watertight mixture to the above-mentioned preferred value, it is mainly necessary to select an ethylene-vinyl acetate copolymer having an appropriate melt index. In addition to the above-mentioned components, the watertight mixture of the present invention may optionally contain ethylene ethyl acrylate copolymer (E
EA), anti-aging agents, processing aids, etc. may be added. [Effects of the Invention] The watertight mixture according to the present invention not only has excellent adhesive strength with insulating resins such as cross-linked polyethylene and conductive metals, but also has excellent adhesive strength with conductive metals against fluctuations in external temperature. However, it is stable for a long time. Therefore, if it is used as a watertight filler for insulated wires, the manufactured wires will have excellent watertightness regardless of whether they are initially or after bending. However, after leaving the insulated wire for a long period of time (especially in the summer), it should be
Even when used in the field, the watertight admixture is peeled off together with the jacket insulation, so the workability of electrical work is always good throughout the year. [Examples] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Examples 1 to 5, Comparative Examples 1 to 6 Watertight mixtures having the compositions of the Examples and Comparative Examples shown in the following table were kneaded in a kneader, and the mixture was mixed in 2. 0mmφ hard copper wire 19
After filling the stranded wire conductor with a cross-sectional area of 6°1 m2, weather-resistant cross-linked polyethylene with a thickness of 2.5 ann was extruded over the stranded wire conductor to produce a water-tight cross-linked polyethylene insulated wire. The following table shows the results of measuring various properties of these watertight mixtures and insulated wires. The various properties in the table were measured and evaluated by the following methods. (1) Melt index (MI) According to the method specified in JIS K 6760 for watertight mixtures, a load of 2,160 g was applied, and 190
The flow rate was measured for 10 minutes at °C. (2) A sheet of watertight mixture (1 mra thick) and a sheet of polyethylene containing a crosslinking agent (2 mm thick) were laminated in sequence on an adhesive copper tape (1 mm thick, 25 mm wide), and 50 k
The sample is heated at 170° C. for 10 minutes under a pressure of g/clT+2 (the polyethylene sheet is partially left unattached to the watertight mixture sheet). Grip the unbonded part of the polyethylene sheet using a tensile tester,
It was pulled at a speed of 100 stops per minute. The results were evaluated according to the following criteria. Weak: Peeling occurs between the copper tape and the sheet of watertight mixture,
Suitable for those whose strength is less than 0.5 kg/25 +n width: Peeling between the copper tape and the sheet of watertight mixture,
If the strength is 0.5 kg/251111 width or more Strong: The sheet of the watertight mixture is torn off and remains on both the copper tape and the polyethylene sheet (3) Filling The watertight mixture is press-fitted into the stranded conductor. It was evaluated based on the workability when doing so. (4) Non-dripping property Strip off the outer insulation of 3cI11 at one end of a 13cm long insulated wire, hang it vertically in a constant temperature bath at 100℃ with that part facing down, and drip the watertight mixture after 24 hours have passed. The presence or absence of was investigated and the results were evaluated according to the following criteria. O: Not dripped ×: Dropped (5) Initial watertightness 0.5kg/Cl112 from one end of a 2m long insulated wire
After applying a water pressure of 24 hours and leaving it for 24 hours, the presence or absence of water leakage from the other end was checked and evaluated according to the following criteria. O: No water leakage As,
It was bent 5 times, and then the same test as the above watertightness test was conducted, and evaluation was made using the same criteria. (7) When the outer insulation layer of the early peelable insulated wire was peeled off with an electrical knife,
The amount of watertight admixture remaining on the stranded wire conductor was evaluated according to the following criteria. O: No watertight admixture remained. X: Even a small amount of watertight admixture remained. The sample was left in the sun, cooled to -10°C, and subjected to the same test as the peelability test described above, and evaluated using the same criteria. As is clear from the table, the watertight mixtures of Examples 1 to 5 and the insulated wires manufactured using them all had excellent properties. In Example 5, the melt index of the watertight mixture was adjusted by blending an ethylene ethyl acrylate copolymer. On the other hand, in the watertight mixture of Comparative Example 1, the melt index was too large, so the non-dripability was poor. vice versa,
In the watertight mixture of Comparative Example 2, the melt index was too small, resulting in poor filling properties. The watertight mixture of Comparative Example 3 was 2.2.4-)samethyl-
Since the blended amount of the 1,2-dihydroquinoline polymer was small, the insulated wire manufactured using the same had poor peelability after heating. On the contrary, the watertight mixture of Comparative Example 4 has 2
．． Since the blended amount of the 2,4-trimethyl-1,2-dihydroquinoline polymer was large, the watertightness of the insulated wire was poor. Since the watertight mixture of Comparative Example 5 contained a large amount of the modified polyolefin adhesive, the insulated wire manufactured using the watertight mixture had poor peelability both initially and after heating. On the other hand, in the watertight mixture of Comparative Example 6, the amount of the modified polyolefin adhesive was small, so the watertightness of the insulated wire was poor. Patent applicant: TAC Electric Cable Co., Ltd., agent: Patent attorney Tsuta 1) Shoko and 1 other person

Claims (1)

[Claims] 1. 1 to 20 parts by weight of a modified polyolefin adhesive based on 100 parts by weight of ethylene vinyl acetate copolymer; 2.
A watertight mixture comprising 0.1 to 20 parts by weight of a 2,4-trimethyl-1,2-dihydroquinoline polymer. 2. The modified polyolefin adhesive has in its molecular chain,
The watertight mixture according to claim 1, characterized in that it is made of a modified ethylene-vinyl acetate copolymer having at least two polar groups selected from hydroxyl, acetoxyl, and carboxyl groups. 3. The watertight mixture according to claim 1 or 2, which has a melt index of 5 to 200.