JPH0311267B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composite of an ethylene polymer composition and a metal that has excellent resistance to deterioration due to contact with metal, and specifically relates to a composite of a primary insulating layer in which the metal conductor is an ethylene polymer composition. It is a coated cable, and a semiconductive ethylene polymer composition layer containing a conductive material such as carbon black is interposed between the metal conductor and the insulating layer, and each of these layers is made of metal and an insulating layer. Cables made of ethylene polymer compositions that prevent deterioration accelerated by contact with metals.Other uses include ethylene polymer compositions that have excellent resistance to metal deterioration and include foaming agents and/or crosslinking agents. Foam insulated cables, thermally insulated metal pipes or plates coated with a composition and also having powder or fibrous metal embedded therein or surface coated with metal;
It is a composite of an ethylene polymer composition and metal that has excellent resistance to metal deterioration. The ethylene polymer composition that prevents the acceleration of deterioration caused by metals is composed of an ethylene polymer, 0.01 to 2.0 parts by weight, preferably 0.02 to 1.0 parts by weight, of a phenolic antioxidant and a chemical structural formula of (R-S- _C2H4 - _COO - _CH2- ) _4C (wherein R is saturated or unsaturated alkyl or cycloalkyl) 0.01 to 2.0 parts by weight, preferably
It is characterized by a combination of 0.02 to 1.0 parts by weight,
This is a composition in which other necessary additives are added depending on the purpose. In the present invention, the ethylene-based polymer composition is a polymer containing ethylene as a main component, and includes high-pressure methods and medium-low pressure methods, and if there are copolymerization components, they are α-olefin, vinyl ester, etc. , acrylic ester, acrylic acid, etc. Furthermore, these ethylene polymers may be those obtained by graft polymerization with an organic acid or its anhydride, if necessary. One of the antioxidants of the present invention is generally referred to as a phenol type antioxidant, and it is desirable that a plurality of phenol groups exist and that the phenol groups are hindered phenols. The specific antioxidant that can be combined with this is a thioether having a pentaerythritol type skeleton, and the alkyl group or unsaturated alkyl group is preferably _C10 to _C22 , and stearyl, lauryl, oleyl, etc. are practical. . As additives for stabilizing polyolefins in the presence of metals, that is, in a contact state or an encapsulated state, dihydrazone derivatives (Japanese Patent Publication No.
1940), Hydroxy-substituted benzoyl hydrazide (Special Publication No. 1965-3965, Special Publication No. 18607, No. 43-1960, Special Publication No. 43-18607, Special Publication No. 43-1860)
23768), a technique in which a heterocyclic compound having two or more nitrogen atoms and a compound containing at least an amino group is used in combination with other antioxidants (Japanese Patent Publication No. 46-22574), etc. are known. However, the polyolefin referred to in these prior art was an effort to make polypropylene molded products practical, which deteriorate significantly even at temperatures around room temperature due to contact with copper, and even now, 10 years later, Polypropylene, which has excellent electrical properties, is rarely used as an insulating material that requires durability, such as for electric wires. On the other hand, electric wires and cables using ethylene polymer as an insulating material have been extremely common, and in response to the recent industrial trends that demand improved heat resistance, they have been made with copper, etc. There was a need to solve the problem that contact between metal and ethylene polymer accelerates oxidation and fall of molded products. As a countermeasure to this problem, a technique was disclosed (Japanese Patent Publication No. 49-18461) in which a phenolic stabilizer, sulfur, and di(orthobenzamide phenyl) disulfide were added together.
It is said that the ability to prevent copper damage and deterioration at high temperatures is insufficient. Additionally, U.S. Patent No. 3,440,210, and
No. 3,660,438, German Patent No. 2,164,234, US Pat. No. 3,826,781, etc., all of which involve the selection of hydrazide compounds as metal deactivators. These substances have disadvantages such as having a higher melting point than ethylene polymers, having no affinity with ethylene polymers, and not being uniformly dispersed, and also decomposing and releasing gas when kneaded at high temperatures. This generates air bubbles in the molded product, causing deterioration of the quality of the molded product, especially the deterioration of electrical insulation, and an additional 5%
The additive itself causes increased energy loss under the electric field. Therefore, it is desired to develop additives that are effective even when added in small amounts. Polyolefins are widely used as molding materials due to their excellent electrical, mechanical, and chemical properties, but propylene-based polymers are difficult to catalyze in applications that require contact with metals, especially copper. Despite the development of many copper-damaging and deterioration inhibitors, it is difficult to use them for electric wires, cables, and other applications that come into contact with copper. On the other hand, compared to propylene polymers, ethylene polymers are more stable with respect to copper near room temperature, and deterioration is less likely to be accelerated by other metals. For this reason, it is widely used as an insulating material for electric wires and cables. However, as conditions for using electric wires and cables, polyethylene insulated wires that can withstand use in high-temperature environments have come to be required.
Moreover, even in ethylene polymers, which were conventionally thought to have little acceleration of deterioration due to metals such as copper, it has become impossible to ignore the acceleration of deterioration caused by ions of metals such as copper acting as catalysts. The present invention not only prevents oxidative deterioration in a high-temperature atmosphere, but also makes it possible to obtain an ethylene polymer composition that does not easily deteriorate even when used at high temperatures in the presence of metal ions such as copper. This made it possible to create composites of objects and metals. The ethylene polymer composition is an ethylene polymer
Add phenolic antioxidant to 100 parts by weight.
0.01 to 2.0 parts by weight, preferably 0.02 to 1.0 parts by weight, and the chemical structure is (RS-C ₂ H ₄ -COO-CH ₂ -) ₄ C, and R is saturated or unsaturated alkyl or cycloalkyl. Selected from A, the amount added is 0.01
~2.0 parts by weight, preferably 0.02 to 1.0 parts by weight of an antioxidant. Even if an appropriate amount of crosslinking agent or crosslinking aid is added to this composition depending on the use,
The effect is not inhibited, and semiconductive ethylene polymers are used in which a conductive agent such as conductive carbon black is mixed between the metal used as an electric conductor, the insulator, and the ethylene polymer molded product used. In the case where a composition is included, the semiconductive ethylene polymer composition also has heat resistance by containing the combination of oxidation stabilizers that have excellent ability to prevent deterioration caused by metal ions as disclosed in the present invention. improves. The stabilizer combinations of the present invention are also effective in other applications that are used in contact with metal surfaces, such as adhesives and electromagnetic shielding materials. The next thing to note is that ethylene polymers and phenolic antioxidants, or ethylene polymers and oxidants whose chemical structural formula is (R-S-C ₂ H ₄ -COO-CH ₂ -) ₄ C Compositions consisting of combinations of inhibitors are known and are also known for their antioxidant effects.
However, it is completely inadequate in its ability to prevent accelerated deterioration caused by contact with metals or the inclusion of metal ions. (See Comparative Examples) Furthermore, combinations of each of these antioxidants and other antioxidants are also ineffective in accelerating deterioration caused by metals. However, in the case of a combination of a phenolic antioxidant and an antioxidant with the chemical structural formula (R-S-C ₂ H ₄ -COO-CH ₂ -) ₄ C, as in the composition constituting the present invention, As is clear from the results of the examples, we have discovered the existence of a synergistic effect that effectively suppresses deterioration even in contact with metals and in the presence of metal ions, and significantly extends the time for signs of deterioration to appear. The invention has been achieved. In the present invention, the amount of these antioxidants combined is 0.01 to 2.0 parts by weight, preferably 0.02 to 1.0 parts by weight. The synergistic effect is not clear when below 0.01 parts by weight, and when above 2.0 parts by weight, the rate of improvement in resistance to metal damage deterioration is small, but other adverse effects, such as leaching of antioxidants onto the surface. , suppression of crosslinking agent reaction,
This is due to the appearance of increased dielectric loss, etc. The typical effects of the present invention will be explained below using Examples and Comparative Examples. To prepare the samples in Table 1, first 120
Melt and knead a predetermined amount of polyethylene using two kneading rolls kept at ℃, add the predetermined amounts of various antioxidants shown in Table 1, knead for 15 minutes to uniformly disperse, and then form into a sheet. . In the case of Examples 3 and 4 in which dicumyl peroxide is blended as a crosslinking agent, dicumyl peroxide is mixed after the above-mentioned 15 minutes of kneading, and after kneading for an additional 3 minutes, a sheet is formed. Next, this sheet was heated to 180℃ using a mold.
Pressure molding was performed for 15 minutes to obtain a sheet with a thickness of 1 mm. The sheet obtained by these operations is punched out using a punch cutter to obtain a disk-shaped specimen with a diameter of 40 mm. Using this specimen, a deterioration test using copper ions, which has a remarkable deterioration reaction even among metals, will be conducted. The method is to place the specimen on fresh copper foil and place it in a constant temperature oven with air circulation at 150℃.
Accelerated deterioration is carried out, the time for the appearance of brown spots is measured, and the resistance to metal damage deterioration is determined based on this.
This determination method is an extremely sensitive measuring method that can detect signs of deterioration at a time when no signs of deterioration are observed using various mechanical measuring methods. The time for onset of signs of deterioration in Table 1 refers to the time until the brown spots are clearly observed. Wire/cable insulators that come into direct contact with copper conductors are judged to have passed the accelerated deterioration test described above if they do not show any discoloration or spots for over 72 hours. Copper was used as the metal because not only does it noticeably accelerate deterioration, but also because it is often used in contact with ethylene polymers as an electrical conductor or as a building material. From the results in Table 1, phenolic antioxidants, amine antioxidants, quinoline antioxidants, and antioxidants represented by the chemical formula (R-S-C ₂ H ₄ -COO-CH ₂ ) ₄ C are , the prior art formulation of only a single substance has insufficient resistance to deterioration caused by metals such as copper (see Comparative Examples 1.2.3 and 4).
However, in the case of the present invention, which is a combination of a phenolic antioxidant and an antioxidant having the structure (R-S-C ₂ H ₄ -COO-CH ₂ -) ₄ C (see Examples 1.2.3 and 4) has remarkable resistance to deterioration caused by metals such as copper. In this case, it is understood that even if dicumyl peroxide is blended as a crosslinking agent, a different type of phenolic antioxidant may be used. However, combinations of phenolic antioxidants and amine-based or quinoline-based antioxidants, and combinations of antioxidants with the chemical structural formula (R-S-C ₂ H ₄ -COO-CH ₂ -) ₄ C and amine-based or quinoline antioxidants, Similarly, combinations of antioxidants are not effective in suppressing the acceleration of deterioration caused by metals such as copper.

【table】

[Table] As described above, the ethylene polymer composition disclosed in the present invention has extremely excellent resistance to metal damage and deterioration, so it does not deteriorate even when used as a composite in direct contact with metals at relatively high temperatures. It has a great effect in suppressing this and has great utility value. Although the specific uses of the present invention will be easily understood from the above description, a summary thereof will be listed below. (1) Electric wires and cables that have a structure in which an ethylene polymer composition is in direct contact with a metal conductor. (Low voltage cables, communication cables, etc.) (2) High voltage cables that are electric wires and cables and have a structure in which a semiconductive ethylene polymer composition is in contact with a metal conductor, and semiconductive crosslinked ethylene polymer compositions. A high-voltage cable with a structure in which the metal conductor is in contact with the metal conductor. (3) Cross-linked and/or polymerized ethylene polymer compositions and related parts that primarily function as thermal insulation materials for copper pipes, copper plates, etc. in thermal energy-related equipment. (4) A construction material that is a laminated composite material of copper plates, etc. and ethylene polymer. (5) Housings for electronic and electrical products, etc., containing semiconductive ethylene polymer compositions, metallized ethylene polymer sheets, composites of metal foil and ethylene polymer adhesive, magnetic materials and ethylene The housing has a composite of polymers on the front or back surface of the housing. What is important about the above-mentioned composites of ethylene polymers and metals is that they are often exposed to high temperatures and are required to withstand acceleration of oxidative deterioration caused by metals.

Claims (1)

[Scope of Claims] 1. A composite of an ethylene polymer composition and a metal, which has excellent resistance to deterioration due to contact with metal, in which the ethylene polymer composition contains 100 parts by weight of the ethylene polymer. On the other hand, 0.01 to 2.0 parts by weight of a phenolic antioxidant and the general formula (R-S-C ₂ H ₄ -COO-CH ₂ -) ₄ C (However, in the formula, R is saturated or unsaturated alkyl or cycloalkyl. It is characterized by containing 0.01 to 2.0 parts by weight of an antioxidant having the structure (selected from ), and can also contain other additives.
Composite of ethylene polymer composition and metal. 2. The ethylene polymer composition according to claim 1, wherein the metal is an electrical conductor such as copper, and the ethylene polymer composition is an electrical insulator mainly composed of polyethylene or an ethylene-α olefin copolymer. A composite of objects and metals. 3. Ethylene according to claim 1, wherein the metal is an electrical conductor such as copper, and the ethylene polymer composition is an electrical insulator mainly composed of crosslinkable polyethylene or ethylene-α-olefin copolymer. Composite of polymer composition and metal. 4 Polyethylene, ethylene-α olefin copolymer, ethylene vinyl ester copolymer, ethylene-acrylic acid ester, where the metal is an electrical conductor such as copper, and the ethylene polymer composition contains conductive carbon black as an additive. A semiconductive layer containing a copolymer or/and an ethylene-acrylic acid copolymer as a main component;
A composite of the ethylene polymer composition according to claim 1 and a metal, comprising at least the electrical insulating layer according to claim 3. 5. A composite of an ethylene polymer composition and a metal according to claim 1, wherein the metal is a plate or a tube, and the additive of the ethylene polymer composition is a blowing agent and/or a crosslinking agent. 6. A composite of the ethylene polymer composition and metal according to claim 1, wherein the metal is in the form of powder, fine particles, or fibers and is dispersed in the ethylene polymer. 7. The ethylene according to claim 1, wherein the metal is in the form of fiber fabric, mat, or felt, and is embedded in or laminated with the molded article made of the ethylene polymer composition. Composite of polymer and metal. 8. The ethylene polymer and metal composite according to claim 1, wherein the metal is vacuum-deposited, plated, or adhered in the form of a foil to the surface of a molded article of the ethylene polymer composition.