JPH0138806B2 - - Google Patents
Info
- Publication number
- JPH0138806B2 JPH0138806B2 JP8868980A JP8868980A JPH0138806B2 JP H0138806 B2 JPH0138806 B2 JP H0138806B2 JP 8868980 A JP8868980 A JP 8868980A JP 8868980 A JP8868980 A JP 8868980A JP H0138806 B2 JPH0138806 B2 JP H0138806B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- polyethylene
- parts
- density
- coating
- 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
Links
- -1 Polyethylene Polymers 0.000 claims description 19
- 239000004698 Polyethylene Substances 0.000 claims description 19
- 229920000573 polyethylene Polymers 0.000 claims description 19
- 239000000155 melt Substances 0.000 claims description 7
- RXPKHKBYUIHIGL-UHFFFAOYSA-L calcium;12-hydroxyoctadecanoate Chemical compound [Ca+2].CCCCCCC(O)CCCCCCCCCCC([O-])=O.CCCCCCC(O)CCCCCCCCCCC([O-])=O RXPKHKBYUIHIGL-UHFFFAOYSA-L 0.000 claims description 5
- 238000005187 foaming Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 239000011347 resin Substances 0.000 claims description 5
- 229920005989 resin Polymers 0.000 claims description 5
- 239000004604 Blowing Agent Substances 0.000 claims description 4
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 claims description 4
- 239000008116 calcium stearate Substances 0.000 claims description 4
- 235000013539 calcium stearate Nutrition 0.000 claims description 4
- 238000000975 co-precipitation Methods 0.000 claims description 3
- 239000002667 nucleating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 description 13
- 239000011248 coating agent Substances 0.000 description 12
- 229920001903 high density polyethylene Polymers 0.000 description 3
- 239000004700 high-density polyethylene Substances 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 239000011342 resin composition Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010292 electrical insulation Methods 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000004088 foaming agent Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- XOZUGNYVDXMRKW-AATRIKPKSA-N azodicarbonamide Chemical compound NC(=O)\N=N\C(N)=O XOZUGNYVDXMRKW-AATRIKPKSA-N 0.000 description 1
- 235000019399 azodicarbonamide Nutrition 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000006353 environmental stress Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
Landscapes
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Organic Insulating Materials (AREA)
Description
本発明は、通信ケーブル用電線の発泡絶縁被覆
に特に好適な高密度ポリエチレン系樹脂組成物に
関する。
従来、通信ケーブル用電線の発泡絶縁被覆に、
低密度ポリエチレンが使われているが、表面肌の
滑らかさのため摩擦が少ないにもかゝわらず撚り
をかける際にクラツクが発生することがあり、電
気絶縁性も稍不足して漏電するという問題があ
り、一方、高密度ポリエチレンは耐クラツク性は
高いが2000〜3000m/minという高速被覆では、
表面肌が粗になり撚りをかける際に摩擦が強くな
つてクラツクが発生し勝ちであり、発泡気泡が相
対的に大きくしかもその大きさが不均一になりや
すくそのためまたクラツクが発生するという欠点
を有している。
本発明は、これ等の問題に鑑み耐クラツク性の
高い高密度ポリエチレンで高速被覆しても表面肌
を滑らかにしてしかも絶縁気泡が微細にしてその
大きさを均一にすべく種々検討して到達したもの
であり、その要旨は、密度0.95〜0.965ｇ/cm3、メ
ルトインデツクス20〜35ｇ/10minのポリエチレ
ン（以下ポリエチレン(A)と称する）45〜75重量％
及び密度0.930〜0.940ｇ/cm3、ハイロード・メル
トインデツクス３〜６ｇ/10minのポリエチレン
（以下ポリエチレン(B)と称する）25〜55重量％か
らなる樹脂合計量100重量部当り、ヒドロキシス
テアリン酸カルシウム65〜85重量％及びステアリ
ン酸カルシウム15〜35重量％からなる共沈混合物
0.05〜0.5重量部、発泡剤0.1〜2.0重量部及び発泡
核剤0.1〜1.0重量部を含んでなることを特徴とす
る樹脂組成物、である。
本発泡で用いるポリエチレン(A)は流動性が高
く、ポリエチレン(B)は耐環境応力亀裂性に優れる
ポリエチレンであるが、ポリエチレン(A)の密度は
0.95〜0.965ｇ/cm3、ポリエチレン(B)の密度は0.930
〜．940ｇ/cm3の範囲であつてこの範囲未満では被
覆にクラツクが入り易く、この範囲を越えると被
覆の表面肌が粗になり撚りをかける際に摩擦が強
くなつてクラツクが発生し勝ちである。
また、ポリエチレン(A)のメルトインデツクス
（但しここでいうメルトインデツクスとは、
ASTM−Ｄ−1238に準拠し、メルトインデクサ
ーを用いて測定され、温度190℃、荷重2.16Kgの
条件において10分間に押出される樹脂のｇ数であ
る。）は20〜35ｇ/10min、ポリエチレン(B)のハイ
ロード・メルトインデツクス（但しここでいうハ
イロードメルトインデツクスとは、ASTM−Ｄ
−467に準拠し、メルトインデクサーを用いて測
定され、温度190℃、荷重21.6Kgの条件において
10分間に押出される樹脂のｇ数である。）は３〜
６ｇ/10minの範囲であつて、この範囲未満では、
流動性の不足と粘性の増大とにより被覆が切れ勝
ちで被覆が困難であり、さらに発泡気泡の分散が
不均一となり、逆にこの範囲を越えるとダイノズ
ル近傍にいわゆるメヤニと呼ばれる劣化物が堆積
して被覆に付着したり均一な被覆の障害ともなる
上に発泡気泡が大きくなり過ぎしかもその大きさ
が一層不均一になるという現象が発生する。
ポリエチレン(A)45〜75重量％とポリエチレン(B)
25〜55重量％が共存するが、ポリエチレン(A)が45
重量％未満では、流動性が不足して被覆が切れる
懸念があり、ポリエチレン(A)が55重量％を越える
と流動性が大きすぎて偏肉のない均一な被覆が困
難となる。
また、本発明では、ポリエチレン(A)とポリエチ
レン(B)の樹脂合計量100重量部当り、ヒドロキシ
ステアリン酸カルシウム65〜85重量％及びステア
リン酸カルシウム15〜35重量％からなる共沈混合
物0.05〜0.5重量部を含むことが必要である。ヒ
ドロキシステアリン酸カルシウムが65重量％未満
では、被覆の表面肌の滑らかさが不足し85重量％
を越えるとメヤニの発生する懸念がある。共沈混
合物として0.05重量部未満では、被覆の表面肌の
滑らかさが得られず0.5重量部を越えると芯線と
の加熱収縮が大きくなり密着性が不十分となる。
なおヒドロキシステアリン酸カルシウム及びステ
アリン酸カルシウムのうちいずれを欠いてもまた
両者の単なる混合でも被覆の表面肌は改良され
ず、共沈混合物を用いる必要がある。
発泡剤は、固体発泡剤ならアゾジカルボン酸ア
ミド、気体発泡剤なら窒素が好ましいが、0.1重
量部未満であると、充分な発泡倍率が得られず、
2.0重量部を越えると適当な発泡倍率20〜40％の
限度をこえてしまう。なお発泡倍率20％未満では
電気絶縁性が不充分であり軽量化に応えられず、
40％を越えると耐摩耗性が不足する。但しこゝで
いう発泡倍率とは体積増加分の百分率である。
発泡核剤としてはクレイが好ましく他に炭酸カ
ルシウム、タルクなどが挙げられるが0.1重量部
未満ならばセルが粗大となつて表面が粗となり、
逆に1.0重量部を越えるとセルは細いが発泡倍率
が過大となり、極少量の発泡剤を使用しても前記
発泡倍率20〜40％の限度をはるかに越えた過発泡
状態となつてしまう。
さらに、本発明の樹脂組成物としては、密度
0.940ｇ/cm3以上なら被覆のクラツク発生がさらに
防止でき、メルトインデツクス0.2〜1.0ｇ/10min
なら被覆の表面肌の清らかさと被覆の偏肉防止に
さらに優れているので好ましい。
以下に、実施例、比較例を挙げて本発明をさら
に詳細に説明する。
実施例１〜４、比較例１〜５
第１表に示す樹脂組成物を用いて65m/mφ押
出機で溶融押出しながら銅芯線に被覆した。その
条件は、下記のとおりである。また各例の成形
性、得られた被覆の物性を第２表に示す。
押出温度（℃）：C1180、C2200、C3210、H200
スクリユー（rpm）：45〜90
芯線径（ｍ／ｍ）：0.408
コア径（ｍ／ｍ）：0.720
ダイス：３段テーパー、径（ｍ／ｍ）0.76、２、
３、13
テーパー（゜）：６、20、45
ランド（ｍ／ｍ）：10、５、10
The present invention relates to a high-density polyethylene resin composition particularly suitable for foam insulation coating of electric wires for communication cables. Conventionally, foam insulation coatings for communication cable wires were used.
Low-density polyethylene is used, but even though the surface is smooth and there is little friction, cracks can occur when twisting, and the electrical insulation is also slightly lacking, causing electrical leakage. On the other hand, although high-density polyethylene has high crack resistance, it cannot be coated at high speeds of 2000 to 3000 m/min.
The surface texture becomes rough and the friction becomes strong when twisting, which tends to cause cracks, and the foamed bubbles tend to be relatively large and uneven in size, which also causes cracks. have. In view of these problems, the present invention was developed after various studies in order to make the surface smooth even when coated at high speed with high-density polyethylene, which has high crack resistance, and to make the insulation bubbles fine and uniform in size. The gist is that polyethylene (hereinafter referred to as polyethylene (A)) with a density of 0.95 to 0.965 g/cm 3 and a melt index of 20 to 35 g/10 min (hereinafter referred to as polyethylene (A)) 45 to 75% by weight
Calcium hydroxystearate per 100 parts by weight of a total resin consisting of 25 to 55% by weight of polyethylene (hereinafter referred to as polyethylene (B)) with a density of 0.930 to 0.940 g/cm 3 and a high road melt index of 3 to 6 g/10 min. Co-precipitation mixture consisting of 65-85% by weight and 15-35% by weight of calcium stearate
0.05 to 0.5 parts by weight, 0.1 to 2.0 parts by weight of a foaming agent, and 0.1 to 1.0 parts by weight of a foaming nucleating agent. The polyethylene (A) used in this foaming has high fluidity, and the polyethylene (B) has excellent environmental stress cracking resistance, but the density of polyethylene (A) is
0.95-0.965g/cm 3 , the density of polyethylene (B) is 0.930
~． It is in the range of 940g/cm 3 , and if it is less than this range, cracks are likely to occur in the coating, and if it exceeds this range, the surface texture of the coating becomes rough and the friction becomes strong when twisting, which tends to cause cracks. . In addition, the melt index of polyethylene (A) (however, the melt index referred to here is
It is measured using a melt indexer in accordance with ASTM-D-1238, and is the number of grams of resin extruded in 10 minutes at a temperature of 190°C and a load of 2.16 kg. ) is 20~35g/10min, high load melt index of polyethylene (B) (however, the high load melt index referred to here is ASTM-D
-467, measured using a melt indexer at a temperature of 190℃ and a load of 21.6Kg.
This is the number of grams of resin extruded in 10 minutes. ) is 3~
Within the range of 6g/10min, below this range,
Due to the lack of fluidity and increased viscosity, the coating tends to break, making it difficult to coat.Furthermore, the dispersion of foamed cells becomes uneven, and conversely, if this range is exceeded, deteriorated substances called so-called "meyani" will accumulate near the die nozzle. In addition, the bubbles become too large and their sizes become even more uneven. Polyethylene (A) 45-75% by weight and polyethylene (B)
25 to 55% by weight coexists, but polyethylene (A) accounts for 45% by weight.
If the amount is less than 55% by weight, there is a risk that the coating will be cut due to insufficient fluidity, and if the amount of polyethylene (A) exceeds 55% by weight, the fluidity will be too high and it will be difficult to coat uniformly without uneven thickness. Further, in the present invention, 0.05 to 0.5 parts by weight of a coprecipitated mixture consisting of 65 to 85 weight % of calcium hydroxystearate and 15 to 35 weight % of calcium stearate per 100 parts by weight of the total resin amount of polyethylene (A) and polyethylene (B). It is necessary to include If calcium hydroxystearate is less than 65% by weight, the surface smoothness of the coating will be insufficient and 85% by weight
There is a concern that stains may occur if the temperature is exceeded. If the amount of the coprecipitation mixture is less than 0.05 part by weight, the surface of the coating will not be smooth, and if it exceeds 0.5 part by weight, heating shrinkage with the core wire will be large and adhesion will be insufficient.
Note that the surface texture of the coating will not be improved even if either calcium hydroxystearate or calcium stearate is absent, or even if they are simply mixed, it is necessary to use a coprecipitated mixture. As the blowing agent, azodicarboxamide is preferable if it is a solid blowing agent, and nitrogen is preferable if it is a gas blowing agent, but if it is less than 0.1 part by weight, a sufficient expansion ratio cannot be obtained.
If it exceeds 2.0 parts by weight, the appropriate expansion ratio of 20 to 40% will be exceeded. Note that if the foaming ratio is less than 20%, the electrical insulation will be insufficient and it will not be possible to reduce the weight.
If it exceeds 40%, wear resistance will be insufficient. However, the expansion ratio referred to here is the percentage of volume increase. Clay is preferred as the foaming nucleating agent, and other examples include calcium carbonate and talc, but if it is less than 0.1 part by weight, the cells will become coarse and the surface will become rough.
On the other hand, if it exceeds 1.0 parts by weight, the cells will be thin but the expansion ratio will be excessive, and even if a very small amount of the foaming agent is used, the expansion ratio will be in an over-foamed state that far exceeds the limit of 20 to 40%. Furthermore, the resin composition of the present invention has a density of
If it is 0.940g/cm3 or more , cracks in the coating can be further prevented, and the melt index is 0.2 to 1.0g/10min.
This is preferable since the surface of the coating is kept clean and the thickness of the coating is prevented from becoming uneven. The present invention will be explained in more detail below by giving Examples and Comparative Examples. Examples 1 to 4, Comparative Examples 1 to 5 Using the resin compositions shown in Table 1, a copper core wire was coated while being melt-extruded using a 65 m/mφ extruder. The conditions are as follows. Furthermore, the moldability of each example and the physical properties of the obtained coating are shown in Table 2. Extrusion temperature (℃): C 1 180, C 2 200, C 3 210, H200 Screw (rpm): 45-90 Core wire diameter (m/m): 0.408 Core diameter (m/m): 0.720 Die: 3-stage taper , diameter (m/m) 0.76, 2,
3, 13 Taper (°): 6, 20, 45 Land (m/m): 10, 5, 10
【表】【table】
【表】【table】
Claims (1)
ス20〜35ｇ/10minのポリエチレン(A)45〜75重量
％及び密度0.930〜0.940ｇ/cm3、ハイロード・メ
ルトインデツクス３〜６ｇ/10minのポリエチレ
ン(B)25〜55重量％からなる樹脂合計量100重量部
当り、ヒドロキシステアリン酸カルシウム65〜85
重量％及びステアリン酸カルシウム15〜35重量％
からなる共沈混合物0.05〜0.5重量部、発泡剤0.1
〜2.0重量部及び発泡核剤0.1〜1.0重量部を含んで
なることを特徴とする樹脂組成物。1 Polyethylene (A) 45 to 75% by weight with a density of 0.950 to 0.965 g/cm 3 and a melt index of 20 to 35 g/10 min and a density of 0.930 to 0.940 g/cm 3 and a high load melt index of 3 to 6 g/10 min. 65-85 parts by weight of calcium hydroxystearate per 100 parts by weight of a total resin consisting of 25-55% by weight of polyethylene (B)
wt% and calcium stearate 15-35 wt%
Co-precipitation mixture consisting of 0.05-0.5 parts by weight, blowing agent 0.1
2.0 parts by weight and 0.1 to 1.0 parts by weight of a foaming nucleating agent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8868980A JPS5714628A (en) | 1980-06-30 | 1980-06-30 | Resin composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8868980A JPS5714628A (en) | 1980-06-30 | 1980-06-30 | Resin composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5714628A JPS5714628A (en) | 1982-01-25 |
| JPH0138806B2 true JPH0138806B2 (en) | 1989-08-16 |
Family
ID=13949799
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8868980A Granted JPS5714628A (en) | 1980-06-30 | 1980-06-30 | Resin composition |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5714628A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6569299B2 (en) * | 2015-05-25 | 2019-09-04 | 凸版印刷株式会社 | Resin composition, resin sheet, laminated sheet and foamed wallpaper |
-
1980
- 1980-06-30 JP JP8868980A patent/JPS5714628A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5714628A (en) | 1982-01-25 |
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