JPH0254214B2 - - Google Patents
Info
- Publication number
- JPH0254214B2 JPH0254214B2 JP9938582A JP9938582A JPH0254214B2 JP H0254214 B2 JPH0254214 B2 JP H0254214B2 JP 9938582 A JP9938582 A JP 9938582A JP 9938582 A JP9938582 A JP 9938582A JP H0254214 B2 JPH0254214 B2 JP H0254214B2
- Authority
- JP
- Japan
- Prior art keywords
- vinyl aromatic
- polymer block
- block
- aromatic hydrocarbon
- molecular weight
- 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
- 229920000642 polymer Polymers 0.000 claims description 47
- -1 vinyl aromatic hydrocarbons Chemical class 0.000 claims description 42
- 229920002554 vinyl polymer Polymers 0.000 claims description 42
- 229920001400 block copolymer Polymers 0.000 claims description 36
- 150000001993 dienes Chemical class 0.000 claims description 17
- 229920006257 Heat-shrinkable film Polymers 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 7
- 229920005989 resin Polymers 0.000 claims description 7
- 239000011347 resin Substances 0.000 claims description 7
- 229920001225 polyester resin Polymers 0.000 claims description 4
- 239000004645 polyester resin Substances 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 229910052573 porcelain Inorganic materials 0.000 claims description 3
- 239000000470 constituent Substances 0.000 claims description 2
- 238000002372 labelling Methods 0.000 claims description 2
- 150000002739 metals Chemical class 0.000 claims description 2
- 229920006122 polyamide resin Polymers 0.000 claims description 2
- 229920000193 polymethacrylate Polymers 0.000 claims description 2
- 229920005672 polyolefin resin Polymers 0.000 claims description 2
- 229920005668 polycarbonate resin Polymers 0.000 claims 1
- 239000004431 polycarbonate resin Substances 0.000 claims 1
- 238000000034 method Methods 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Natural products C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 7
- 230000002087 whitening effect Effects 0.000 description 6
- 230000007613 environmental effect Effects 0.000 description 5
- 238000004806 packaging method and process Methods 0.000 description 5
- 238000005227 gel permeation chromatography Methods 0.000 description 4
- 229920001519 homopolymer Polymers 0.000 description 4
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 235000013305 food Nutrition 0.000 description 3
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 2
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 229920005684 linear copolymer Polymers 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910000489 osmium tetroxide Inorganic materials 0.000 description 1
- 239000012285 osmium tetroxide Substances 0.000 description 1
- 238000006864 oxidative decomposition reaction Methods 0.000 description 1
- 239000012785 packaging film Substances 0.000 description 1
- 229920006280 packaging film Polymers 0.000 description 1
- 238000012536 packaging technology Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920003217 poly(methylsilsesquioxane) Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- CIHOLLKRGTVIJN-UHFFFAOYSA-N tert‐butyl hydroperoxide Chemical compound CC(C)(C)OO CIHOLLKRGTVIJN-UHFFFAOYSA-N 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
- B29C61/003—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2025/00—Use of polymers of vinyl-aromatic compounds or derivatives thereof as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2096/00—Use of specified macromolecular materials not provided for in a single one of main groups B29K2001/00 - B29K2095/00, as moulding material
- B29K2096/04—Block polymers
Description
本発明は、低温収縮性、耐水白化性及び耐環境
破壊性に優れたブロツク共重合体の熱収縮性フイ
ルムに関する。
収縮包装はこれまでの包装技術では避けられな
かつたダブツキやシワがきれいに解決でき、又商
品に密着した包装や異形物の包装が迅速にできる
ことから最近特に食品包装用にその利用が増加し
ている。従来、収縮包装用フイルム、シート等の
素材としては、低温収縮性、透明性、機械的強度
等の要求特性を満足することから塩化ビニル樹脂
が主に使用されている。しかし塩化ビニル樹脂は
塩化ビニルモノマーや可塑剤類の衛生上の問題、
焼却時の塩化水素の発生問題等からその代替品が
強く要望されている。
一方、ビニル芳香族炭化水素と共役ジエンから
成るブロツク共重合体樹脂は上記の様な諸問題を
有せず、しかも良好な透明性と耐衝撃性を有する
ことから食品包装容器の素材として広く利用され
つつある。しかしながら、従来知られているブロ
ツク共重合体は延伸温度が高く、又収縮を起す温
度も高いため熱収縮包装用素材としては不適当で
あつた。
例えば特開昭49−102494号公報及び特開昭49−
108177号公報にはそれぞれスチレン系炭化水素含
有量50〜95重量％のブロツク共重合体及び該ブロ
ツク共重合体にスチレン系樹脂を配合した組成物
を２軸延伸した包装用フイルムが記載されている
が、かかるフイルムは熱収縮温度が約100℃以上
でなければ十分な収縮率は得られない。
かかるブロツク共重合体の低温収縮性を改良す
る方法も特開昭50−6673号公報や特公昭55−5544
号公報で試みられている。前者の方法は線状共重
合体にチユーブラ法を適用することによつて有効
な高度の配向が起こる様な温度域で膨張延伸して
同時２軸配向を行い、良好な低温熱収縮性を持つ
フイルムを製造する方法である。しかしながら、
この方法においては原料樹脂のブタジエン含有量
の多寡に応じて極めて限選された温度範囲で膨張
延伸を開始し、しかも膨張開始点から膨張終了点
に至る延伸帯域のフイルムに厳密にコントロール
された温度勾配をつけなければ所望の低温熱収縮
性を持つフイルムが得られず、従つて容易に実施
し難いという欠点を有する。又、後者の方法はス
チレン含有量が65〜90％のスチレン・ブタジエン
ブロツク共重合体にスチレン含有量が20〜50％の
スチレン・ブタジエンブロツク共重合体を10〜30
重量％配合することにより低温収縮性の２軸延伸
フイルムを製造する方法であるが、この方法は両
者の混練状態が不良の場合、充分な低温収縮性が
発現できず、混練方法に高度のテクニツクを要し
て容易に実施し難いという欠点を有する。
本発明者らはかかる現状に鑑み、低温収縮性の
優れたブロツク共重合体フイルム、シート等を容
易に得る方法について鋭意検討を進めた結果、ブ
ロツク共重合体を構成するビニル芳香族炭化水素
重合体ブロツクがある特定の範囲の分子量を有す
るブロツク共重合体或いはこの様なブロツク共重
合体に低分子量ビニル芳香族炭化水素重合体や通
常の高分子量ビニル芳香族炭化水素重合体を配合
した組成物が比較的低温で延伸でき、その目的が
達成されることを見い出し、特願昭56−22989号、
特願昭56−63325号及び特願昭56−95314号を出願
した。その後、本発明者らはその改良について更
に検討を進めた結果、ブロツク共重合体中に結合
されているビニル芳香族炭化水素重合体ブロツク
として比較的分子量が小さい成分と、比較的分子
量が大きい成分とを持たせ、しかも両成分の含有
量を適切な範囲に選定することにより低温収縮性
のみならず耐水白化性及び耐環境破壊性に優れた
熱収縮性フイルムが得られることを新たに見い出
し、本発明を完成するに至つた。
即ち、本発明は、少なくとも３個のビニル芳香
族炭化水素を主体とする重合体ブロツクと少なく
とも２個の共役ジエンを主体とする重合体ブロツ
クからなり、ビニル芳香族炭化水素と共役ジエン
との重量比が60：40〜90：10であるブロツク共重
合体で、しかも、ビニル芳香族炭化水素を主体と
する重合体ブロツク中には、ビニル芳香族炭化水
素重合体ブロツクとしては平均分子量が5000以上
の重合体ブロツクはただ一つ存在し、しかもその
重合体ブロツクが平均分子量が5000〜35000のビ
ニル芳香族炭化水素重合体ブロツクA1か平均分
子量が50000以上のビニル芳香族炭化水素重合体
ブロツクA2かのいずれかであつて、A1とA2の重
量比が１：１〜１：６であるブロツク共重合体を
１軸延伸または２軸延伸してなり、延伸方向にお
ける90℃の熱収縮率が10％以上であるブロツク共
重合体の熱収縮性フイルム、及び前記フイルムに
おける１軸延伸成形品を素材とする、金属、磁
器、ガラス、ポリオレフイン系樹脂、ポリメタク
リル酸エステル系樹脂、ポリカーボネート系樹
脂、ポリエステル系樹脂、ポリアミド系樹脂から
選ばれる少なくとも１種を構成素材またはその一
部とする容器の、ラベリングに適したラベル用熱
収縮性フイルムである。
本発明の熱収縮性フイルムは低温において優れ
た収縮性を有するため、収縮包装工程において高
温で長時間加熱すると変質や変形を生じる様な物
品の包装、例えば生鮮食料品やプラスチツク成形
品等の包装に適する。又、本発明の熱収縮性ブロ
ツク共重合体フイルムは耐水白化性に優れるため
該フイルムで被覆した物品を常温で水と長時間接
触させたり、70〜80℃以上の熱水で処理しても白
濁して透明性が失われる（いわゆる水白化）とい
う問題点がない。そのためこの様な条件下に暴ら
すことが必要な用途分野、例えば熱水での殺菌処
理などを要する用途に利用できる。更に、本発明
の熱収縮性フイルムは耐環境破壊性に優れ、本発
明の熱収縮性フイルムで被覆した物品を気温や湿
度変化の激しい屋外環境下に放置しても破壊しに
くいという特長を有する。特に、被覆される物品
が金属、磁器、ガラス、ポリエステル系樹脂など
のように特性、例えば熱膨張率や吸水性などが極
めて異なる材質で構成されている場合には、従来
の熱収縮性フイルムでは被覆後の耐環境破壊性が
劣り、容易にフイルムにクラツクが入るという欠
点を有していたが、本発明の熱収縮性フイルムを
用いた場合にはこの様な問題がなく、長期の自然
環境下における放置に耐える。従つて本発明の熱
収縮性フイルムはかかる利点を生かして、上記の
様な材質で構成される容器類のラベルなどの用途
にとりわけ好適に利用できる。
以下、本発明を詳細に説明する。
本発明で使用するブロツク共重合体は、少なく
とも３個、好ましくは４個以上のビニル芳香族炭
化水素を主体とする重合体ブロツクと、少なくと
も２個、好ましくは３個以上の共役ジエンを主体
とする重合体ブロツクを有するブロツク共重合体
である。ここでビニル芳香族炭化水素を主体とす
る重合体ブロツクとは、ビニル芳香族炭化水素の
含有量が50重量％を超える、好ましくは70重量％
以上の重合体ブロツクである。又、共役ジエンを
主体とする重合体ブロツクとは、共役ジエンの含
有量が50重量％以上、好ましくは70重量％以上の
重合体ブロツクである。更に、ビニル芳香族炭化
水素を主体とする重合体ブロツク中には平均分子
量が5000以上のビニル芳香族炭化水素重合体ブロ
ツクがただ一つ存在し、共役ジエンを主体とする
重合体ブロツク中には、平均分子量が5000以上の
ビニル芳香族炭化水素共重合体ブロツクは存在し
ない。また、ビニル芳香族炭化水素を主体とする
重合体ブロツク及び共役ジエンを主体とする重合
体ブロツクにおいて共役ジエンとランダム共重合
しているビニル芳香族炭化水素が存在する場合、
このビニル芳香族炭化水素は重合体鎖中に均一に
分布していても、またテーパー（漸減）状に分布
していてもよい。本発明で使用するブロツク共重
合体のビニル芳香族炭化水素含有量は60〜90重量
％、好ましくは65〜85重量％、更に好ましくは68
〜78重量％である。ビニル芳香族炭化水素の含有
量が60重量％未満の場合は引張強度や剛性が劣
り、熱収縮性フイルムとして不適当である。又、
90重量％を超える場合は耐衝撃性が劣るため好ま
しくない。
本発明で使用するブロツク共重合体の特徴の１
つは、ブロツク共重合体が分子量の異なる２種類
のビニル芳香族炭化水素重合体ブロツク群を有す
ることである。即ち、本発明で使用するブロツク
共重合体は平均分子量が5000〜35000、好ましく
は7000〜30000、更に好ましくは10000〜25000で
あるビニル芳香族炭化水素重合体ブロツクA1と、
平均分子量が50000以上、好ましくは60000〜
200000、更に好ましくは65000〜150000であるビ
ニル芳香族炭化水素重合体ブロツクA2とを有し、
しかもA1とA2の重量比は１：１〜１：６、好ま
しくは１：２〜１：５、更に好ましくは１：３〜
１：４である。尚、本発明において平均分子量と
は、GPC（ゲルパーミエーシヨンクロマトグラフ
イー）測定においてゲルパーミエーシヨンクロマ
トグラムのピークの位置から求めた分子量をい
う。GPCにおける検量線は、GPC用として市販
されている標準ポリスチレンを用いて作成したも
のを使用する。又、A1とA2の重量比はゲルパー
ミエーシヨンクロマトグラムにおいて、分子量が
5000〜35000の領域のピーク面積と分子量が50000
以上の領域のピーク面積の相対比をいう。A1の
平均分子量が上記範囲より小さくなると耐衝撃性
が低下し、上記範囲より大きくなると低温収縮性
が悪くなるため好ましくない。又、A2の平均分
子量が上記範囲より小さくなると耐水白化性及び
耐環境破壊性が悪化するため好ましくない。更に
A1とA2の重量比に関しては、A1の量が上記範囲
より多くなると耐水白化性及び耐環境破壊性が悪
くなり、又逆にA1の量が少なくなると低温収縮
性が低下するため好ましくない。ビニル芳香族炭
化水素重合体ブロツクA1及びA2の平均分子量及
びそれらの量的関係は、ブロツク共重合体を四酸
化オスミウムを触媒としてジーターシヤリーブチ
ルハイドロパーオキサイドにより酸化分解する方
法（L.M.KOLTHOFF、etal.、J.polym.Sci.1、
429（1946）に記載の方法）により分解して得られ
るビニル芳香族炭化水素重合体ブロツクのGPC
測定により求めることができる。即ち、上記の分
解法で得られたビニル芳香族炭化水素重合体ブロ
ツクのゲルパーミエーシヨンクロマトグラムにお
いて、平均分子量が5000〜35000の領域に存在す
るピークの位置からA1の平均分子量が求まり、
平均分子量が50000以上の領域に存在するピーク
の位置からA2の平均分子量が求まる。そしてA1
とA2の量的関係は平均分子量が5000〜35000の領
域に存在するビニル芳香族炭化水素重合体ブロツ
クの面積と平均分子量が50000以上の領域に存在
するビニル芳香族炭化水素重合体ブロツク群の面
積を比較することにより求まる。又、ブロツク共
重合体を製造するために使用する触媒量、モノマ
ー量及び重合条件が明らかになつている場合に
は、計算によりA1及びA2の平均分子量、A1とA2
の量的関係を求めることができる。
本発明で使用するブロツク共重合体において、
共役ジエンを主体とする重合体ブロツクの分子量
は特に制限はないが、一般には数平均分子量が
500〜200000、好ましくは1000〜100000である。
又、ブロツク共重合体の全体としての数平均分子
量は、20000〜500000、好ましくは50000〜300000
である。
本発明において特に好ましいブロツク共重合体
は、該ブロツク共重合体を構成するＡブロツクが
実質上ビニル芳香族炭化水素単独重合体で構成さ
れ、しかもＢブロツクが実質上共役ジエン単独重
合体で構成されているブロツク共重合体である。
ここでＡブロツクが実質上ビニル芳香族炭化水素
単独重合体で構成され、しかもＢブロツクが実質
上共役ジエン単独重合体で構成されているブロツ
ク共重合体とは、Ａブロツク及びＢブロツク中に
共役ジエンとランダム共重合しているビニル芳香
族炭化水素の量が少ないブロツク共重合体を意味
し、具体的には下式で表示されるブロツク共重合
体の全体としての非ブロツク率が15重量％以下、
好ましくは10重量％以下、更に好ましくは５重量
％以下のブロツク共重合体である。
The present invention relates to a heat-shrinkable block copolymer film that has excellent low-temperature shrinkability, water whitening resistance, and environmental damage resistance. Shrink packaging has been increasingly used in recent years, especially for food packaging, as it can effectively eliminate the bagging and wrinkles that were unavoidable with conventional packaging technology, and it can also quickly wrap products tightly or irregularly shaped items. . Conventionally, vinyl chloride resin has been mainly used as a material for shrink wrapping films, sheets, etc. because it satisfies required properties such as low-temperature shrinkability, transparency, and mechanical strength. However, vinyl chloride resin has hygienic problems due to vinyl chloride monomer and plasticizers.
There is a strong demand for alternatives due to the problem of hydrogen chloride generation during incineration. On the other hand, block copolymer resins made of vinyl aromatic hydrocarbons and conjugated dienes do not have the above problems and have good transparency and impact resistance, so they are widely used as materials for food packaging containers. It is being done. However, conventionally known block copolymers are unsuitable as materials for heat-shrinkable packaging because of their high stretching temperatures and high shrinkage temperatures. For example, JP-A-49-102494 and JP-A-49-
Publication No. 108177 describes a packaging film obtained by biaxially stretching a block copolymer having a styrene hydrocarbon content of 50 to 95% by weight, and a composition in which the block copolymer is blended with a styrene resin. However, such a film cannot achieve sufficient shrinkage unless the heat shrinkage temperature is about 100°C or higher. Methods for improving the low-temperature shrinkability of such block copolymers are also disclosed in JP-A-50-6673 and JP-B-Sho 55-5544.
This is attempted in the Publication No. In the former method, by applying the tubular method to a linear copolymer, simultaneous biaxial orientation is achieved through expansion stretching in a temperature range where effective high degree of orientation occurs, resulting in good low-temperature heat shrinkability. This is a method of manufacturing film. however,
In this method, expansion and stretching is started in a very limited temperature range depending on the butadiene content of the raw resin, and the temperature in the stretching zone from the expansion start point to the expansion end point is strictly controlled. Unless a gradient is provided, a film having the desired low-temperature heat shrinkability cannot be obtained, and therefore it has the disadvantage that it is difficult to implement easily. In the latter method, a styrene-butadiene block copolymer with a styrene content of 20-50% is added to a styrene-butadiene block copolymer with a styrene content of 65-90%.
This method produces a biaxially stretched film with low-temperature shrinkability by blending the two by weight; however, if the kneading conditions of both components are poor, sufficient low-temperature shrinkability cannot be achieved, and the kneading method requires advanced techniques. This method has the disadvantage that it requires a lot of time and is difficult to implement. In view of the current situation, the present inventors have carried out extensive studies on a method for easily obtaining block copolymer films, sheets, etc. with excellent low-temperature shrinkability. A block copolymer whose coalesced block has a molecular weight within a certain range, or a composition in which such a block copolymer is blended with a low molecular weight vinyl aromatic hydrocarbon polymer or a normal high molecular weight vinyl aromatic hydrocarbon polymer. It was discovered that the object could be stretched at a relatively low temperature and the purpose was achieved, and patent application No. 56-22989,
Patent application No. 56-63325 and Patent application No. 95314 were filed. After that, the present inventors further investigated the improvement and found that the vinyl aromatic hydrocarbon polymer block bonded in the block copolymer has a component with a relatively small molecular weight and a component with a relatively large molecular weight. We have newly discovered that by selecting the contents of both components within an appropriate range, it is possible to obtain a heat-shrinkable film that has not only low-temperature shrinkability but also water whitening resistance and environmental damage resistance. The present invention has now been completed. That is, the present invention consists of a polymer block mainly composed of at least three vinyl aromatic hydrocarbons and at least two polymer blocks mainly composed of conjugated dienes, and the weight of the vinyl aromatic hydrocarbons and the conjugated dienes is A block copolymer with a ratio of 60:40 to 90:10, and in the polymer block mainly composed of vinyl aromatic hydrocarbon, the average molecular weight of the vinyl aromatic hydrocarbon polymer block is 5000 or more. There is only one polymer block, and that polymer block is vinyl aromatic hydrocarbon polymer block A 1 with an average molecular weight of 5,000 to 35,000 or vinyl aromatic hydrocarbon polymer block A with an average molecular weight of 50,000 or more. 2 , the block copolymer having a weight ratio of A1 and A2 of 1:1 to 1:6 is uniaxially or biaxially stretched, and is heated at 90°C in the stretching direction. Heat-shrinkable films of block copolymers with a shrinkage rate of 10% or more, and metals, porcelain, glass, polyolefin resins, polymethacrylate ester resins, and polycarbonates made from uniaxially stretched molded products of the films. This heat-shrinkable film for labels is suitable for labeling containers whose constituent material or part thereof is at least one selected from polyester resins, polyester resins, and polyamide resins. Since the heat-shrinkable film of the present invention has excellent shrinkability at low temperatures, it can be used to package items that would deteriorate or deform if heated at high temperatures for a long period of time during the shrink-wrapping process, such as packaging of perishable foods and plastic molded products. suitable for Furthermore, since the heat-shrinkable block copolymer film of the present invention has excellent water whitening resistance, it does not cause damage even if articles coated with the film are left in contact with water at room temperature for a long period of time or treated with hot water of 70 to 80°C or higher. There is no problem of clouding and loss of transparency (so-called water whitening). Therefore, it can be used in fields of application that require exposure to such conditions, such as applications that require sterilization treatment with hot water. Furthermore, the heat-shrinkable film of the present invention has excellent environmental damage resistance, and has the feature that it is difficult to break even if an article coated with the heat-shrinkable film of the present invention is left in an outdoor environment with severe changes in temperature and humidity. . In particular, when the article to be coated is made of materials such as metal, porcelain, glass, and polyester resin, which have extremely different properties such as coefficient of thermal expansion and water absorption, conventional heat-shrinkable films cannot be used. The heat shrinkable film of the present invention does not have such problems and can be used in the natural environment for a long time. Withstands being left unattended. Therefore, the heat-shrinkable film of the present invention can be particularly suitably used for applications such as labels for containers made of the above-mentioned materials by taking advantage of these advantages. The present invention will be explained in detail below. The block copolymer used in the present invention has at least 3, preferably 4 or more vinyl aromatic hydrocarbon-based polymer blocks and at least 2, preferably 3 or more conjugated dienes. It is a block copolymer having a polymer block. Here, the polymer block mainly composed of vinyl aromatic hydrocarbons means that the content of vinyl aromatic hydrocarbons exceeds 50% by weight, preferably 70% by weight.
This is the above polymer block. Further, a polymer block mainly composed of a conjugated diene is a polymer block having a conjugated diene content of 50% by weight or more, preferably 70% by weight or more. Furthermore, in the polymer block mainly composed of vinyl aromatic hydrocarbons, there is only one vinyl aromatic hydrocarbon polymer block with an average molecular weight of 5000 or more, and in the polymer block mainly composed of conjugated dienes, there is only one vinyl aromatic hydrocarbon polymer block with an average molecular weight of 5000 or more. , there is no vinyl aromatic hydrocarbon copolymer block with an average molecular weight of 5000 or more. In addition, when there is a vinyl aromatic hydrocarbon randomly copolymerized with a conjugated diene in a polymer block mainly composed of a vinyl aromatic hydrocarbon and a polymer block mainly composed of a conjugated diene,
The vinyl aromatic hydrocarbon may be uniformly distributed in the polymer chain or may be tapered. The vinyl aromatic hydrocarbon content of the block copolymer used in the present invention is 60 to 90% by weight, preferably 65 to 85% by weight, more preferably 68% by weight.
~78% by weight. If the vinyl aromatic hydrocarbon content is less than 60% by weight, the film will have poor tensile strength and rigidity, making it unsuitable for use as a heat-shrinkable film. or,
If it exceeds 90% by weight, it is not preferable because impact resistance is poor. 1. Characteristics of the block copolymer used in the present invention
One is that the block copolymer has two types of vinyl aromatic hydrocarbon polymer blocks having different molecular weights. That is, the block copolymer used in the present invention is a vinyl aromatic hydrocarbon polymer block A1 having an average molecular weight of 5,000 to 35,000, preferably 7,000 to 30,000, and more preferably 10,000 to 25,000;
Average molecular weight is 50,000 or more, preferably 60,000 or more
200,000, more preferably 65,000 to 150,000, and a vinyl aromatic hydrocarbon polymer block A2 of
Moreover, the weight ratio of A 1 and A 2 is 1:1 to 1:6, preferably 1:2 to 1:5, more preferably 1:3 to
The ratio is 1:4. In the present invention, the average molecular weight refers to the molecular weight determined from the peak position of a gel permeation chromatogram in GPC (gel permeation chromatography) measurement. The calibration curve for GPC is created using standard polystyrene commercially available for GPC. Also, the weight ratio of A 1 and A 2 is determined by the molecular weight in the gel permeation chromatogram.
Peak area in the region of 5000-35000 and molecular weight of 50000
It refers to the relative ratio of peak areas in the above regions. If the average molecular weight of A 1 is smaller than the above range, the impact resistance will decrease, and if it is larger than the above range, the low temperature shrinkability will deteriorate, which is not preferable. Furthermore, if the average molecular weight of A 2 is smaller than the above range, water whitening resistance and environmental damage resistance will deteriorate, which is not preferable. Furthermore
Regarding the weight ratio of A 1 and A 2 , if the amount of A 1 exceeds the above range, water whitening resistance and environmental damage resistance will deteriorate, and conversely, if the amount of A 1 decreases, low temperature shrinkability will decrease. Undesirable. The average molecular weights of vinyl aromatic hydrocarbon polymer blocks A 1 and A 2 and their quantitative relationship were determined by the method of oxidative decomposition of block copolymers with tertiary butyl hydroperoxide using osmium tetroxide as a catalyst (LMKOLTHOFF, etal., J.polym.Sci.1,
429 (1946))
It can be determined by measurement. That is, in the gel permeation chromatogram of the vinyl aromatic hydrocarbon polymer block obtained by the above decomposition method, the average molecular weight of A1 is determined from the position of the peak that exists in the average molecular weight region of 5,000 to 35,000.
The average molecular weight of A 2 is determined from the position of the peak that exists in the region where the average molecular weight is 50,000 or more. and A 1
The quantitative relationship between Determined by comparing the areas. In addition, if the amount of catalyst, amount of monomer, and polymerization conditions used to produce the block copolymer are known, the average molecular weight of A 1 and A 2 and the average molecular weight of A 1 and A 2 can be determined by calculation.
The quantitative relationship can be found. In the block copolymer used in the present invention,
There is no particular restriction on the molecular weight of a polymer block mainly composed of conjugated dienes, but generally the number average molecular weight is
500-200000, preferably 1000-100000.
Further, the number average molecular weight of the block copolymer as a whole is 20,000 to 500,000, preferably 50,000 to 300,000.
It is. A particularly preferred block copolymer in the present invention is one in which the A block constituting the block copolymer is substantially composed of a vinyl aromatic hydrocarbon homopolymer, and the B block is substantially composed of a conjugated diene homopolymer. It is a block copolymer.
Here, a block copolymer in which the A block is substantially composed of a vinyl aromatic hydrocarbon homopolymer and the B block is substantially composed of a conjugated diene homopolymer is defined as It means a block copolymer with a small amount of vinyl aromatic hydrocarbon randomly copolymerized with a diene, and specifically, the overall non-block rate of the block copolymer expressed by the following formula is 15% by weight. below,
Preferably, the amount of the block copolymer is 10% by weight or less, more preferably 5% by weight or less.
【表】
〓化水素の重量〓 〓ロツクの重量 〓
[Table] Weight of hydrogen chloride Weight of lock
Claims (1)
体とする重合体ブロツクと少なくとも２個の共役
ジエンを主体とする重合体ブロツクからなり、ビ
ニル芳香族炭化水素と共役ジエンとの重量比が
60：40〜90：10であるブロツク共重合体で、しか
も、ビニル芳香族炭化水素を主体とする重合体ブ
ロツク中には、ビニル芳香族炭化水素重合体ブロ
ツクとしては平均分子量が5000以上の重合体ブロ
ツクはただ一つ存在し、しかもその重合体ブロツ
クが平均分子量が5000〜35000のビニル芳香族炭
化水素重合体ブロツクA1か平均分子量が50000以
上のビニル芳香族炭化水素重合体ブロツクA2か
のいずれかであつて、A1とA2の重量比が１：１
〜１：６であるブロツク共重合体を、１軸延伸ま
たは２軸延伸してなり、延伸方向における90℃の
熱収縮率が10％以上であるブロツク共重合体の熱
収縮性フイルム。 ２ 少なくとも３個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも２個の共役
ジエンを主体とする重合体ブロツクからなり、ビ
ニル芳香族炭化水素と共役ジエンとの重量比が
60：40〜90：10であるブロツク共重合体で、しか
も、ビニル芳香族炭化水素を主体とする重合体ブ
ロツク中には、ビニル芳香族炭化水素重合体ブロ
ツクとしては平均分子量が5000以上の重合体ブロ
ツクはただ一つ存在し、しかもその重合体ブロツ
クが平均分子量が5000〜35000のビニル芳香族炭
化水素重合体ブロツクA1か平均分子量が50000以
上のビニル芳香族炭化水素重合体ブロツクA2か
のいずれかであつて、A1とA2の重量比が１：１
〜１：６であるブロツク共重合体を、１軸延伸し
てなり、延伸方向における90℃の熱収縮率が10％
以上である、金属、磁器、ガラス、ポリオレフイ
ン系樹脂、ポリメタクリル酸エステル系樹脂、ポ
リカーボネート系樹脂、ポリエステル系樹脂、ポ
リアミド系樹脂から選ばれる少なくとも１種を構
成素材又はその一部とする、容器のラベリングに
適したラベル用熱収縮性フイルム。[Scope of Claims] 1 Consists of a polymer block mainly composed of at least three vinyl aromatic hydrocarbons and at least two polymer blocks mainly composed of conjugated dienes, comprising a polymer block composed mainly of vinyl aromatic hydrocarbons and conjugated dienes. The weight ratio
It is a block copolymer with a ratio of 60:40 to 90:10, and in the polymer block mainly composed of vinyl aromatic hydrocarbon, there is a polymer block with an average molecular weight of 5000 or more, which is unusual for a vinyl aromatic hydrocarbon polymer block. There is only one combined block, and the polymer block is either vinyl aromatic hydrocarbon polymer block A 1 with an average molecular weight of 5,000 to 35,000 or vinyl aromatic hydrocarbon polymer block A 2 with an average molecular weight of 50,000 or more. either, and the weight ratio of A 1 and A 2 is 1:1
A heat-shrinkable film of a block copolymer obtained by uniaxially or biaxially stretching a block copolymer having a ratio of 1:6 to 1:6, and having a heat shrinkage rate of 10% or more at 90°C in the stretching direction. 2 Consisting of a polymer block mainly composed of at least three vinyl aromatic hydrocarbons and at least two polymer blocks mainly composed of conjugated dienes, the weight ratio of the vinyl aromatic hydrocarbons to the conjugated dienes is
It is a block copolymer with a ratio of 60:40 to 90:10, and in the polymer block mainly composed of vinyl aromatic hydrocarbon, there is a polymer block with an average molecular weight of 5000 or more, which is unusual for a vinyl aromatic hydrocarbon polymer block. There is only one combined block, and the polymer block is either vinyl aromatic hydrocarbon polymer block A 1 with an average molecular weight of 5,000 to 35,000 or vinyl aromatic hydrocarbon polymer block A 2 with an average molecular weight of 50,000 or more. either, and the weight ratio of A 1 and A 2 is 1:1
A block copolymer with a ratio of ~1:6 is uniaxially stretched, and the heat shrinkage rate at 90°C in the stretching direction is 10%.
Containers whose constituent material or part thereof is at least one selected from the above metals, porcelain, glass, polyolefin resins, polymethacrylate resins, polycarbonate resins, polyester resins, and polyamide resins. Heat-shrinkable film for labels suitable for labeling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9938582A JPS58217324A (en) | 1982-06-11 | 1982-06-11 | Heat-shrinkable film of block copolymer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9938582A JPS58217324A (en) | 1982-06-11 | 1982-06-11 | Heat-shrinkable film of block copolymer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58217324A JPS58217324A (en) | 1983-12-17 |
| JPH0254214B2 true JPH0254214B2 (en) | 1990-11-21 |
Family
ID=14246036
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9938582A Granted JPS58217324A (en) | 1982-06-11 | 1982-06-11 | Heat-shrinkable film of block copolymer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58217324A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1426165B1 (en) * | 2001-08-17 | 2009-12-23 | Toyobo Co., Ltd. | Heat-shrinkable polystyrene based resin film roll and method for production thereof, and heat-shrinkable label |
| JP4138578B2 (en) * | 2003-05-26 | 2008-08-27 | 奇美實業股▲分▼有限公司 | Block copolymer |
-
1982
- 1982-06-11 JP JP9938582A patent/JPS58217324A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58217324A (en) | 1983-12-17 |
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