JPH0443089B2 - - Google Patents
Info
- Publication number
- JPH0443089B2 JPH0443089B2 JP59221863A JP22186384A JPH0443089B2 JP H0443089 B2 JPH0443089 B2 JP H0443089B2 JP 59221863 A JP59221863 A JP 59221863A JP 22186384 A JP22186384 A JP 22186384A JP H0443089 B2 JPH0443089 B2 JP H0443089B2
- Authority
- JP
- Japan
- Prior art keywords
- crosslinked
- polymer
- water
- oxygen
- present
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 claims description 17
- 150000001451 organic peroxides Chemical class 0.000 claims description 11
- 229920006037 cross link polymer Polymers 0.000 claims description 10
- 238000000354 decomposition reaction Methods 0.000 claims description 9
- 238000010292 electrical insulation Methods 0.000 claims description 9
- XMNIXWIUMCBBBL-UHFFFAOYSA-N 2-(2-phenylpropan-2-ylperoxy)propan-2-ylbenzene Chemical group C=1C=CC=CC=1C(C)(C)OOC(C)(C)C1=CC=CC=C1 XMNIXWIUMCBBBL-UHFFFAOYSA-N 0.000 claims description 7
- 238000000576 coating method Methods 0.000 claims description 5
- 239000012212 insulator Substances 0.000 claims description 5
- 229920000642 polymer Polymers 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000009413 insulation Methods 0.000 claims description 4
- 229920000620 organic polymer Polymers 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 3
- -1 polyethylene Polymers 0.000 claims description 2
- 229920000573 polyethylene Polymers 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 20
- 238000010438 heat treatment Methods 0.000 description 15
- 238000006297 dehydration reaction Methods 0.000 description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 9
- 239000001301 oxygen Substances 0.000 description 9
- 229910052760 oxygen Inorganic materials 0.000 description 9
- OIGWAXDAPKFNCQ-UHFFFAOYSA-N 4-isopropylbenzyl alcohol Chemical compound CC(C)C1=CC=C(CO)C=C1 OIGWAXDAPKFNCQ-UHFFFAOYSA-N 0.000 description 7
- 229920003020 cross-linked polyethylene Polymers 0.000 description 6
- 239000004703 cross-linked polyethylene Substances 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 4
- 238000006116 polymerization reaction Methods 0.000 description 4
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical compound CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- KWOLFJPFCHCOCG-UHFFFAOYSA-N Acetophenone Chemical compound CC(=O)C1=CC=CC=C1 KWOLFJPFCHCOCG-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 240000005572 Syzygium cordatum Species 0.000 description 1
- 235000006650 Syzygium cordatum Nutrition 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 238000010526 radical polymerization reaction Methods 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 150000003509 tertiary alcohols Chemical class 0.000 description 1
Landscapes
- Processes Of Treating Macromolecular Substances (AREA)
- Organic Insulating Materials (AREA)
Description
［産業上の利用分野］
本発明は架橋高分子中の水分含有量を低減せし
める方法に関する。
［従来の技術］
電気絶縁性が要求される架橋高分子材料、たと
えば絶縁ケーブルの絶縁被覆においては、できる
だけ水分含有量を低減せしめることが必要であ
る。なぜなら、水分含有量が多いとボイドなどが
発生し、送電時などの電圧印加時に水ツリーと称
される現象が生じて電気絶縁性が大幅に低下して
しまうからである。
この電気絶縁性の低下は、絶縁ケーブルの接続
部に顕著に現われる。絶縁ケーブルの接続は、通
常接続すべきケーブルの端部の絶縁被覆を剥ぎ取
り、絶縁被覆端部をペンシリングする。ついで導
体同士を接続したのち、ペンシリングした部分に
有機過酸化物を含む補強用の高分子絶縁物を施
し、加熱された金型により加圧して絶縁被覆部お
よび補強部両者を一体に接合し、架橋を行なうこ
とにより行なわれている。
［発明が解決しようとする問題点］
しかしながら、接続の結果、接続部近辺の熱が
加えられた部分の電気絶縁性が他の部分に比して
大きく低下してしまうことがしばしばみられる。
本発明者らは、そうした接続部近辺の電気絶縁
性の低下の原因を検討したところ、熱が加えられ
た部分の架橋高分子中の水分量が増大しており、
その増大は、有機過酸化物から生成した酸素存在
下でのアルコールの分子内脱水反応に起因するこ
とを見出した。
この脱水反応を有機過酸化物がたとえばジクミ
ルパーオキサイドであるばあいにつき具体的に説
明する。
まず加熱によりつぎの反応式(1)にしたがつて分
解し、ラジカルを発生し、ついでアセトフエノン
やクミルアルコールなどの分解残渣を架橋物中に
残す。
かかる分解残渣のうちクミルアルコールは、酸
素存在下での加熱により脱水反応して架橋高分子
物質マトリツクス中に水を放出する（反応式(2)）。
この脱水反応は150℃以上でO2存在下にて容易
に進行し、特に180℃あたりから急激に大きくな
る。その結果架橋高分子中に水が生成することに
なり、水と高分子との相溶性の点から水は凝集
し、ボイドの発生につながり、絶縁物の電気絶縁
性を低下させてしまうのである。
本発明の目的は、加熱時に生ずる前記反応式(2)
で示される脱水反応を抑制することにより、架橋
高分子中の水分含有量の増加を抑える方法を提供
することにある。
［問題点を解決するための手段］
本発明は、有機過酸化物分解残渣を含有する架
橋された有機高分子を加熱する際に、酸素フリー
の状態で加熱することを特徴とする架橋高分子中
の水分含有量を低減せしめる方法に関する。
［作用および実施例］
本発明の方法はモノマーの重合時の水分の発生
を抑制するものではなく、重合反応（ラジカル重
合反応に限定されない）により生成した有機過酸
化物により架橋された高分子化合物を再加熱した
際の水分の発生を抑制する方法に関する。
本発明の方法は、前記脱水反応における触媒の
作用を果たす酸素をできるだけ存在させずに加熱
し、脱水反応を生起させない点に特徴がある。酸
素の存在はできるだけ少ない方が好ましく、酸素
の入らない完全密閉系で加熱するか、またはN2、
He、CO2、Ar、SF6などの不活性ガス中で加熱
するのが好ましい。後者のばあい、酸素含有量が
５％（容量％、以下同様）以下であればかなりの
割合で水の発生を抑制できる。好ましくは２％以
下、とくに0.5％以下にするとよい。
不活性ガス雰囲気下で加熱処理するためには、
たとえば不活性ガスなどを常時送風する、加熱処
理部分をケースなどで囲み、その内部を不活性ガ
スなどで置換するなどの仕方が採用されうる。
また、酸素が入らないような密閉系で加熱処理
をおこなうばあい、加熱される部分を酸素透過率
の低い物質、たとえば船などの金属テープやナイ
ロン、ポリフツ化ビニリデンなどの樹脂テープで
密閉して酸素との接触を断つ仕方や、加熱される
部分にぴつたり合う金型を用いて加熱する仕方な
どが採用されうる。
本発明の方法は加熱を180℃以上で行なう。こ
れは、有機過酸化物分解残渣の脱水反応による水
分の発生が180℃から特に急激に増大するからで
ある。
本発明の方法が対象とする有機高分子化合物
は、有機過酸化物分解残渣を含有する架橋高分子
化合物である。
高分子化合物としては有機過酸化物を用いて重
合または架橋されたもので、とくに電気絶縁性を
有するものがあげられ、たとえばポリオレフイン
などにおいてとくに有用である。ポリオレフイン
としてはポリエチレン、エチレン−酢酸ビニル共
重合体などがあげられ、それらのうちポリエチレ
ンにとくに顕著な効果を奏する。
有機過酸化物としては、分解により脱水反応を
生起する分解生成物を生ぜしめるものがあげら
れ、たとえば分解して第３級アルコールを生ずる
クミルパーオキサイドやジクミルパーオキサイド
などがある。
本発明の方法は種々の加熱処理に適用できる
が、とくに架橋ポリエチレンで絶縁被覆された
CVケーブルの接続時の加熱処理に適する。
つぎに本発明の方法を実施例に基づいて説明す
るが、本発明はかかる実施例のみに限定されるも
のではない。
実施例 １
５ml容の耐圧容器にジクミルパーオキサイドを
用いて架橋された架橋ポリエチレン片（10mm×20
mm×１mm）を入れ、容器内雰囲気を第１表に示す
雰囲気にしたのち容器を第１表に示す温度に加熱
維持し、同表に示す経過時間ごとに容器内のガス
を抜き取り、クミルアルコールの量および前記反
応式(2)にしだがつて生成するα−メチルスチレン
の量をガスクロマトグラフイーにより測定し、雰
囲気ガス中の［α−メチルスチレン］／［クミル
アルコール］のモル比の経時変化を調べた。結果
を第１表に示す。
なお、モル比が大きくなることはクミルアルコ
ールが脱水反応を起し、α−メチルスチレンと水
の生成が大きくなることを意味している。
なお、用いた架橋ポリエチレンは、低密度ポリ
エチレン（融点110〜115℃、密度0.92ｇ／cm3）
100部にジクミルパーオキサイド2.0部および酸化
防止剤0.3部を加えて溶融混練し、架橋成形した
ものである。
[Industrial Field of Application] The present invention relates to a method for reducing the water content in crosslinked polymers. [Prior Art] In crosslinked polymer materials that require electrical insulation, such as insulation coatings for insulated cables, it is necessary to reduce the water content as much as possible. This is because if the water content is high, voids will occur, and a phenomenon called water tree will occur when voltage is applied during power transmission, resulting in a significant drop in electrical insulation. This reduction in electrical insulation is noticeable at the connection portion of the insulated cable. To connect insulated cables, the insulation coating is usually stripped off from the ends of the cables to be connected, and the ends of the insulation coating are penciled. After connecting the conductors, a reinforcing polymer insulator containing organic peroxide is applied to the penciled part, and pressure is applied using a heated mold to join both the insulating coating and the reinforcing part together. , by crosslinking. [Problems to be Solved by the Invention] However, as a result of the connection, it is often seen that the electrical insulation properties of the portion to which heat is applied near the connection portion are greatly reduced compared to other portions. The present inventors investigated the cause of the decrease in electrical insulation near such connection parts, and found that the amount of water in the crosslinked polymer increased in the areas where heat was applied.
It has been found that the increase is due to the intramolecular dehydration reaction of alcohol in the presence of oxygen generated from organic peroxides. This dehydration reaction will be specifically explained in the case where the organic peroxide is, for example, dicumyl peroxide. First, it is decomposed by heating according to the following reaction formula (1) to generate radicals, and then decomposition residues such as acetophenone and cumyl alcohol are left in the crosslinked product. Among such decomposition residues, cumyl alcohol undergoes a dehydration reaction by heating in the presence of oxygen and releases water into the crosslinked polymer material matrix (reaction formula (2)). This dehydration reaction easily progresses in the presence of O 2 at temperatures above 150°C, and increases rapidly especially around 180°C. As a result, water is generated in the crosslinked polymer, and due to the compatibility between water and the polymer, the water aggregates, leading to the generation of voids and reducing the electrical insulation properties of the insulator. . The object of the present invention is to solve the reaction formula (2) that occurs during heating.
An object of the present invention is to provide a method for suppressing an increase in water content in a crosslinked polymer by suppressing the dehydration reaction shown in the following. [Means for Solving the Problems] The present invention provides a crosslinked polymer characterized in that when heating a crosslinked organic polymer containing an organic peroxide decomposition residue, the crosslinked polymer is heated in an oxygen-free state. The present invention relates to a method for reducing the moisture content in a liquid. [Operations and Examples] The method of the present invention does not suppress the generation of water during the polymerization of monomers, but rather suppresses the generation of water during the polymerization of monomers, but does not suppress the generation of water during polymerization of monomers, but rather suppresses the production of polymer compounds crosslinked by organic peroxides produced by polymerization reactions (not limited to radical polymerization reactions). The present invention relates to a method for suppressing the generation of moisture when reheating. The method of the present invention is characterized in that heating is performed in the absence of oxygen, which acts as a catalyst in the dehydration reaction, as much as possible, so that the dehydration reaction does not occur. It is preferable that the presence of oxygen be as low as possible, so heating should be done in a completely closed system that does not contain oxygen, or N 2 ,
Preferably, heating is performed in an inert gas such as He, CO2 , Ar, SF6 . In the latter case, if the oxygen content is 5% (volume %, the same applies hereinafter) or less, the generation of water can be suppressed to a considerable extent. It is preferably 2% or less, particularly 0.5% or less. For heat treatment under an inert gas atmosphere,
For example, methods such as constantly blowing an inert gas or the like, or surrounding the heat-treated portion with a case or the like, and replacing the inside with an inert gas or the like may be adopted. In addition, when heat treatment is performed in a closed system that prevents oxygen from entering, the area to be heated should be sealed with a material with low oxygen permeability, such as metal tape from ships, or resin tape such as nylon or polyvinylidene fluoride. A method of cutting off contact with oxygen or a method of heating using a mold that tightly fits the part to be heated may be adopted. In the method of the present invention, heating is performed at 180°C or higher. This is because the generation of water due to the dehydration reaction of the organic peroxide decomposition residue increases particularly rapidly from 180°C. The organic polymer compound targeted by the method of the present invention is a crosslinked polymer compound containing an organic peroxide decomposition residue. Examples of the polymer compound include those polymerized or crosslinked using organic peroxides, which have particularly electrical insulation properties, and are particularly useful in, for example, polyolefins. Examples of the polyolefin include polyethylene and ethylene-vinyl acetate copolymer, among which polyethylene exhibits particularly remarkable effects. Examples of organic peroxides include those that produce decomposition products that cause dehydration reactions upon decomposition, such as cumyl peroxide and dicumyl peroxide, which decompose to produce tertiary alcohols. Although the method of the present invention can be applied to various heat treatments, it is particularly applicable to
Suitable for heat treatment when connecting CV cables. Next, the method of the present invention will be explained based on examples, but the present invention is not limited only to these examples. Example 1 A piece of cross-linked polyethylene cross-linked using dicumyl peroxide (10 mm x 20
mm x 1 mm) to bring the atmosphere inside the container to the atmosphere shown in Table 1.The container was then heated and maintained at the temperature shown in Table 1, and the gas in the container was removed at each elapsed time shown in the table. The amount of alcohol and the amount of α-methylstyrene produced according to reaction formula (2) above were measured by gas chromatography, and the molar ratio of [α-methylstyrene]/[cumyl alcohol] in the atmospheric gas was determined over time. We investigated the changes. The results are shown in Table 1. Note that an increase in the molar ratio means that cumyl alcohol undergoes a dehydration reaction, resulting in an increase in the production of α-methylstyrene and water. The cross-linked polyethylene used was low-density polyethylene (melting point 110-115°C, density 0.92 g/cm 3 ).
2.0 parts of dicumyl peroxide and 0.3 parts of an antioxidant were added to 100 parts, melt-kneaded, and cross-linked.
【表】
実施例 ２
18容の密封容器に架橋ポリエチレン絶縁被覆
ケーブル（ZF−30RおよびＸ−470）を入れ、室
温下で真空（0.1mmＨｇ）としたのちN2ガスで置
換して180℃で２時間加熱し、架橋ポリエチレン
中の水分含有量をカールフイツシヤー水分計で測
定した。
比較のため、N2ガスに代えて空気で置換した
ほかは同様にして加熱し、架橋ポリエチレン中の
水分含有量を測定した。それらの結果を第２表に
示す。[Table] Example 2 A cross-linked polyethylene insulated cable (ZF-30R and X-470) was placed in an 18-capacity sealed container, and after creating a vacuum (0.1 mmHg) at room temperature, the air was replaced with N2 gas and heated at 180°C. After heating for 2 hours, the water content in the crosslinked polyethylene was measured using a Karl Fischer moisture meter. For comparison, the water content in the crosslinked polyethylene was measured by heating in the same manner except that air was used instead of N 2 gas. The results are shown in Table 2.
【表】
第１表および第２表の結果から明らかなよう
に、空気やO2ガス雰囲気中でジクミルパーオキ
サイドの分解生成物であるクミルアルコールを含
む架橋ポリエチレンを加熱すると、クミルアルコ
ールの量が減少する一方、水分含有量が増大して
ボイドが多数発生していた。
しかしながら、N2ガス雰囲気中で加熱したば
あいは、クミルアルコールも水分含有量も殆ど変
化せず、電気絶縁性が低下しないことがわかる。[Table] As is clear from the results in Tables 1 and 2, when crosslinked polyethylene containing cumyl alcohol, which is a decomposition product of dicumyl peroxide, is heated in an air or O2 gas atmosphere, cumyl alcohol While the amount of water decreased, the water content increased and many voids were generated. However, when heated in an N 2 gas atmosphere, the cumyl alcohol and water content hardly change, indicating that the electrical insulation property does not deteriorate.
Claims (1)
有機高分子を180℃以上に加熱する際に、酸素フ
リーの状態で加熱することを特徴とする架橋高分
子中の水分含有量を低減する方法。 ２ 有機高分子が電気絶縁用の高分子絶縁物であ
る特許請求の範囲第１項記載の方法。 ３ 高分子絶縁物が絶縁ケーブルの絶縁被覆であ
る特許請求の範囲第２項記載の方法。 ４ 高分子絶縁物がポリエチレンである特許請求
の範囲第２項または第３項記載の方法。 ５ 有機過酸化物がジクミルパーオキサイドであ
る特許請求の範囲第１項記載の方法。[Scope of Claims] 1. Moisture in a crosslinked polymer, which is characterized in that the crosslinked organic polymer containing organic peroxide decomposition residue is heated to 180°C or higher in an oxygen-free state. How to reduce content. 2. The method according to claim 1, wherein the organic polymer is a polymer insulator for electrical insulation. 3. The method according to claim 2, wherein the polymeric insulator is an insulation coating of an insulated cable. 4. The method according to claim 2 or 3, wherein the polymeric insulator is polyethylene. 5. The method according to claim 1, wherein the organic peroxide is dicumyl peroxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22186384A JPS61101535A (en) | 1984-10-22 | 1984-10-22 | Reduction of moisture content in crosslinked polymer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22186384A JPS61101535A (en) | 1984-10-22 | 1984-10-22 | Reduction of moisture content in crosslinked polymer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61101535A JPS61101535A (en) | 1986-05-20 |
| JPH0443089B2 true JPH0443089B2 (en) | 1992-07-15 |
Family
ID=16773367
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22186384A Granted JPS61101535A (en) | 1984-10-22 | 1984-10-22 | Reduction of moisture content in crosslinked polymer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61101535A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5658713A (en) * | 1979-10-15 | 1981-05-21 | Hitachi Cable | Method of treating connection* termination and repair of rubber and plastic insulated cable |
| JPS5810385A (en) * | 1981-07-09 | 1983-01-20 | 日立電線株式会社 | Method of forming connector of insulated cable |
| JPS5847831A (en) * | 1981-09-18 | 1983-03-19 | Hitachi Constr Mach Co Ltd | Oil-pressure circuit for oil-pressure shovel |
| JPS60172182A (en) * | 1984-02-15 | 1985-09-05 | 住友電気工業株式会社 | Connector of crosslinked polyethylene cable |
-
1984
- 1984-10-22 JP JP22186384A patent/JPS61101535A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5658713A (en) * | 1979-10-15 | 1981-05-21 | Hitachi Cable | Method of treating connection* termination and repair of rubber and plastic insulated cable |
| JPS5810385A (en) * | 1981-07-09 | 1983-01-20 | 日立電線株式会社 | Method of forming connector of insulated cable |
| JPS5847831A (en) * | 1981-09-18 | 1983-03-19 | Hitachi Constr Mach Co Ltd | Oil-pressure circuit for oil-pressure shovel |
| JPS60172182A (en) * | 1984-02-15 | 1985-09-05 | 住友電気工業株式会社 | Connector of crosslinked polyethylene cable |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61101535A (en) | 1986-05-20 |
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