JPS6231016B2 - - Google Patents
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- Publication number
- JPS6231016B2 JPS6231016B2 JP54145434A JP14543479A JPS6231016B2 JP S6231016 B2 JPS6231016 B2 JP S6231016B2 JP 54145434 A JP54145434 A JP 54145434A JP 14543479 A JP14543479 A JP 14543479A JP S6231016 B2 JPS6231016 B2 JP S6231016B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- styrene
- parts
- component
- composition
- 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
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- Compositions Of Macromolecular Compounds (AREA)
Description
【発明の詳細な説明】
本発明は透明性の優れた耐衝撃性ポリスチレン
樹脂組成物に関し、詳しくは汎用ポリスチレンを
ベースとしてこれに２種類の特定のスチレン―ブ
タジエンブロツク共重合体を一定割合で混合して
なる透明性、耐衝撃性ともに優れたポリスチレン
樹脂組成物に関する。
一般に汎用ポリスチレンは成形しやすく、また
透明性が良好であるため広範囲にわたつて用いら
れているが、耐衝撃性に劣るという欠点がある。
そのため従来から、この汎用ポリスチレンにス
チレン―ブタジエンブロツク共重合体を添加する
ことが広く行われているが、得られる組成物は耐
衝撃性の向上と引換えに透明性が著しく低下し、
これを原料とする成形品の実用強度は充分であつ
ても商品価値が低減するという欠点があつた。
そこで本発明者らは上記従来技術の欠点を克服
し、透明性を維持しつつ耐衝撃性を改善したポリ
スチレン樹脂組成物を開発すべく鋭意研究を重ね
た。その結果、ポリスチレンに特定のスチレン／
ブタジエン比の範囲を有する２種類の線状スチレ
ン―ブタジエンブロツク共重合体を、一定範囲で
添加することにより目的とするすぐれた物性を有
するポリスチレン樹脂組成物が得られることを見
出し、本発明を完成するに至つた。
すなわち本発明は、(A)汎用ポリスチレン90〜50
重量部、(B)スチレン成分を60重量％以上含有する
線状スチレン―ブタジエンブロツク共重合体５〜
30重量部および(C)スチレン成分を60重量％以下含
有する線状スチレン―ブタジエンブロツク共重合
体５〜20重量部よりなる透明性の優れた耐衝撃性
ポリスチレン樹脂組成物を提供するものである。
本発明の組成物においてベースとして用いられ
る成分は(A)成分である汎用ポリスチレンである。
この汎用ポリスチレンは通常、重量平均分子量は
200000〜400000であり、メルトインデツクスは
0.1〜40g／10分（200℃）、好ましくは１〜10g／
10分（200℃）のものである。耐衝撃性は不充分
であるが透明性にすぐれたものである。本発明で
は(B)および(C)成分を加えることによつて、上記汎
用ポリスチレンの透明性を維持しつつ耐衝撃性を
強化するものである。従つて(A)成分として透明性
の小さい耐衝撃性ポリスチレン等を用いると得ら
れる組成物は耐衝撃性は大きなものとなるが、透
明性が不充分であるため、本発明の目的を達成す
ることはできない。
また本発明の(A)成分である汎用ポリスチレンの
配合量は、組成物全体100重量部あたり90〜50重
量部、好ましくは80〜65重量部とすべきである。
続いて本発明の(B)成分としては、スチレン成分
を60重量％以上含有する線状スチレン―ブタジエ
ンブロツク共重合体が用いられる。この(B)成分の
配合量は組成物全体100重量部あたり５〜30重量
部、好ましくは10〜20重量部の範囲とすべきであ
る。５重量部以下では得られる組成物の透明性が
不充分なものとなり、また30重量部以上にすると
組成物の剛性が低下する。
さらに本発明の(C)成分としては、スチレン成分
を60重量％以下含有する線状スチレン―ブタジエ
ンブロツク共重合体が用いられる。この(C)成分の
配合量は組成物全体100重量部あたり５〜20重量
部、好ましくは10〜15重量部とすべきである。５
重量部以下では得られる組成物の衝撃強度、特に
フイルムインパクト強さが不充分なものとなり、
また20重量部以上にすると、組成物の透明性が低
下する。
上記の(B)，(C)成分である線状スチレン―ブタジ
エンブロツク共重合体の分子構造は、スチレン重
合ブロツクをＳ、ブタジエン重合ブロツクをＢで
表わすと（Ｓ―Ｂ―）oＳ，（Ｓ―Ｂ）o，Ｂ―（Ｓ―
Ｂ）oの如く示されるものの１種または２種以上の
組合わせであり、各共重体全体として(B)成分はス
チレン成分を60重量％以上含有したものであり、
(C)成分はスチレン成分を60重量％以下の範囲で含
有したものである。
本発明においては上述の(A)成分である汎用ポリ
スチレンに(B)，(C)成分である２種類の線状スチレ
ン―ブタジエンブロツク共重合体を添加すること
が必要である。いずれか一方のみの添加では、充
分な耐衝撃性や透明性を付与することができな
い。
本発明の組成物は、上述の(A)，(B)，(C)成分を所
定範囲内の割合にて混合することによつて製造す
る。上記各成分の混練にあたつては、乾燥混合と
溶融混合の併用法、一段溶融混合法、多段溶融混
合法等各種の方法を用いることができる。混合お
よび混練の順序は特に制限はなく、たとえば３成
分を同時に混合、混練してもよく、また(A)成分で
ある汎用ポリスチレンに、(B)，(C)成分のどちらか
一方を加えて混合、混練し、得られた中間混合物
に残りの成分を加えて混合、混練し、目的とする
組成物を製造してもよい。
なお、この際に用いる混練機はバンバリーミキ
サー、コニーダー、押出機等各種のものをあげる
ことができる。
かくして得られた本発明のポリスチレン樹脂組
成物は、全光線透過率、かすみ度等で表示される
透明性のすぐれたものであると共に、フイルムイ
ンパクト、衝撃穴あけ強さ等で示される耐衝撃性
の大きなものである。特に衝撃穴あけ強さについ
ては近似成分の配合組成物に比し著しく向上した
ものである。そのため本発明の組成物は、各種成
形材料、特に薄物成形容器の成形材料として有効
に利用することができる。
次に本発明の実施例を比較例と共に示す。
実施例および比較例
所定量の(A)汎用ポリスチレンペレツト（メルト
インデツクス4.1g／10分、重量平均分子量
286000）と(B)線状スチレン―ブタジエンブロツク
共重合体（スチレン成分含量62重量％）および(C)
線状スチレン―ブタジエンブロツク共重合体（ス
チレン成分含量39重量％）の各ペレツトとをＶ型
ブレンダーにて乾燥混合した。次いで得られた混
合物をシリンダー直径50mmのシート製造装置を用
い、200℃にて均一に混練しつつ厚さ0.35mmの目
的組成物のシートを成形した。混合比を段階的に
変化させ、上述の方法で得られる各組成物のシー
トについて各種物性を23℃で測定した。結果を第
１表に示す。
なお以上とは別に、上記(B)線状スチレン―ブタ
ジエンブロツク共重合体（スチレン成分含量62重
量％）に代えて、一般式（Ｓ―Ｂ―）oＹ〔Ｙは放
射状重合体の形成に使用される多官能性処理剤が
誘導される原子（単数または複数）、ｎは該多官
能性処理剤の官能基の数を表わし、少なくとも３
以上の整数である。〕で示される枝分れスチレン
―ブタジエン共重合体（共役ジエン含有率40重量
％以下の枝分れブロツク共重合体としてブタジエ
ン含有率25重量％のスチレン―ブタジエン共重合
体）を用い、他の成分は前記と同じものとした組
成物についても同様に物性を測定した。結果を第
１表に示す。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an impact-resistant polystyrene resin composition with excellent transparency, and more specifically, it is made of general-purpose polystyrene as a base and mixed with two specific styrene-butadiene block copolymers at a constant ratio. The present invention relates to a polystyrene resin composition having excellent transparency and impact resistance. In general, general-purpose polystyrene is widely used because it is easy to mold and has good transparency, but it has the drawback of poor impact resistance. For this reason, it has been widely practiced to add a styrene-butadiene block copolymer to general-purpose polystyrene, but the resulting composition has significantly reduced transparency in exchange for improved impact resistance.
Although molded products made from this material have sufficient practical strength, they have the drawback of reduced commercial value. Therefore, the present inventors have conducted extensive research in order to overcome the drawbacks of the above-mentioned conventional techniques and to develop a polystyrene resin composition that maintains transparency and improves impact resistance. As a result, polystyrene has certain styrene/
It was discovered that a polystyrene resin composition having the desired excellent physical properties could be obtained by adding two types of linear styrene-butadiene block copolymers having a range of butadiene ratios within a certain range, and the present invention was completed. I came to the conclusion. That is, the present invention provides (A) general-purpose polystyrene 90 to 50
Parts by weight, (B) Linear styrene-butadiene block copolymer containing 60% by weight or more of styrene component 5~
The present invention provides an impact-resistant polystyrene resin composition with excellent transparency, comprising 30 parts by weight of a linear styrene-butadiene block copolymer containing 30 parts by weight and (C) a styrene component of 60% by weight or less. . The component used as a base in the composition of the present invention is component (A), a general-purpose polystyrene.
This general-purpose polystyrene usually has a weight average molecular weight of
200000 to 400000, and the melt index is
0.1-40g/10 minutes (200℃), preferably 1-10g/
10 minutes (200℃). Although impact resistance is insufficient, transparency is excellent. In the present invention, by adding components (B) and (C), the impact resistance of the above-mentioned general-purpose polystyrene is enhanced while maintaining its transparency. Therefore, if a low-transparency impact-resistant polystyrene or the like is used as component (A), the resulting composition will have high impact resistance, but the transparency will be insufficient, making it difficult to achieve the object of the present invention. It is not possible. The amount of general-purpose polystyrene, which is component (A) of the present invention, should be 90 to 50 parts by weight, preferably 80 to 65 parts by weight, per 100 parts by weight of the entire composition. Next, as component (B) of the present invention, a linear styrene-butadiene block copolymer containing 60% by weight or more of a styrene component is used. The amount of component (B) to be blended should be in the range of 5 to 30 parts by weight, preferably 10 to 20 parts by weight, per 100 parts by weight of the entire composition. If the amount is less than 5 parts by weight, the resulting composition will have insufficient transparency, and if it is more than 30 parts by weight, the stiffness of the composition will decrease. Further, as component (C) of the present invention, a linear styrene-butadiene block copolymer containing 60% by weight or less of a styrene component is used. The amount of component (C) to be blended should be 5 to 20 parts by weight, preferably 10 to 15 parts by weight, per 100 parts by weight of the entire composition. 5
If it is less than 1 part by weight, the resulting composition will have insufficient impact strength, especially film impact strength.
Moreover, when the amount is 20 parts by weight or more, the transparency of the composition decreases. The molecular structure of the linear styrene-butadiene block copolymer which is the above components (B) and (C) is (S-B-) o S, ( S-B) o ,B-(S-
B) It is one type or a combination of two or more of the following as shown in o , and each copolymer as a whole contains 60% by weight or more of a styrene component,
Component (C) contains a styrene component in an amount of 60% by weight or less. In the present invention, it is necessary to add two types of linear styrene-butadiene block copolymers, which are components (B) and (C), to the general-purpose polystyrene, which is component (A). Addition of only one of them does not provide sufficient impact resistance or transparency. The composition of the present invention is produced by mixing the above-mentioned components (A), (B), and (C) at a ratio within a predetermined range. In kneading the above-mentioned components, various methods can be used, such as a combination of dry mixing and melt mixing, a single-stage melt-mixing method, and a multi-stage melt-mixing method. The order of mixing and kneading is not particularly limited; for example, the three components may be mixed and kneaded at the same time, or one of the components (B) and (C) may be added to the general-purpose polystyrene that is the (A) component. The desired composition may be manufactured by mixing and kneading, adding the remaining components to the obtained intermediate mixture, and mixing and kneading. The kneading machines used in this case include various types such as a Banbury mixer, a co-kneader, and an extruder. The thus obtained polystyrene resin composition of the present invention has excellent transparency as indicated by total light transmittance, haze, etc., and has excellent impact resistance as indicated by film impact, impact puncturing strength, etc. It's a big one. In particular, the impact puncture strength is significantly improved compared to compositions containing similar ingredients. Therefore, the composition of the present invention can be effectively used as a variety of molding materials, particularly as a molding material for thin molded containers. Next, examples of the present invention will be shown together with comparative examples. Examples and Comparative Examples Predetermined amount of (A) general-purpose polystyrene pellets (melt index 4.1 g/10 minutes, weight average molecular weight
286000) and (B) linear styrene-butadiene block copolymer (styrene component content 62% by weight) and (C)
Each pellet of a linear styrene-butadiene block copolymer (styrene component content: 39% by weight) was dry mixed in a V-type blender. Next, the obtained mixture was uniformly kneaded at 200° C. using a sheet manufacturing device having a cylinder diameter of 50 mm, and a sheet of the desired composition having a thickness of 0.35 mm was formed. The various physical properties of the sheets of each composition obtained by the above method were measured at 23° C. while changing the mixing ratio stepwise. The results are shown in Table 1. Separately from the above, in place of the above (B) linear styrene-butadiene block copolymer (styrene component content 62% by weight), general formula (S-B-) o Y [Y is used to form a radial polymer] The atom(s) from which the polyfunctional treatment agent used is derived, n representing the number of functional groups of the polyfunctional treatment agent, at least 3
is an integer greater than or equal to ] using a branched styrene-butadiene copolymer (styrene-butadiene copolymer with a butadiene content of 25% by weight as a branched block copolymer with a conjugated diene content of 40% by weight or less), and other The physical properties of a composition containing the same ingredients as above were also measured in the same manner. The results are shown in Table 1. 【table】
第１図は成形品座屈強度を測定するために組成
物シートから成形した逆角錐台のトレー（蓋な
し）の斜視図である。
FIG. 1 is a perspective view of an inverted pyramidal tray (without lid) formed from a composition sheet for measuring the buckling strength of a molded article.
Claims (1)
ン成分を60重量％以上含有する線状スチレン―ブ
タジエンブロツク共重合体５〜30重量部および(C)
スチレン成分を60重量％以下含有する線状スチレ
ン―ブタジエンブロツク共重合体５〜20重量部よ
りなる透明性の優れた耐衝撃性ポリスチレン樹脂
組成物。1 (A) 90 to 50 parts by weight of general-purpose polystyrene, (B) 5 to 30 parts by weight of a linear styrene-butadiene block copolymer containing 60% by weight or more of a styrene component, and (C)
An impact-resistant polystyrene resin composition having excellent transparency and comprising 5 to 20 parts by weight of a linear styrene-butadiene block copolymer containing 60% by weight or less of a styrene component.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14543479A JPS5670043A (en) | 1979-11-12 | 1979-11-12 | Shock-resistant polystyrene resin composition with high transparency |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14543479A JPS5670043A (en) | 1979-11-12 | 1979-11-12 | Shock-resistant polystyrene resin composition with high transparency |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5670043A JPS5670043A (en) | 1981-06-11 |
| JPS6231016B2 true JPS6231016B2 (en) | 1987-07-06 |
Family
ID=15385148
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14543479A Granted JPS5670043A (en) | 1979-11-12 | 1979-11-12 | Shock-resistant polystyrene resin composition with high transparency |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5670043A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5089558A (en) * | 1989-04-26 | 1992-02-18 | Bridgestone/Firestone, Inc. | Thermoformable blends of multiblock polymer compositions with polystyrene |
| CA2055199C (en) * | 1991-02-12 | 2003-10-07 | William G. Blasius, Jr. | Transparent high impact alloy |
| US5294677A (en) * | 1991-09-12 | 1994-03-15 | Novacor Chemicals (International) S.A. | Housewares |
| JP5218718B2 (en) * | 2004-12-20 | 2013-06-26 | ジェイエスアール クレイトン エラストマー株式会社 | Thermoplastic resin composition |
| JP2019127525A (en) * | 2018-01-24 | 2019-08-01 | マーベリックパートナーズ株式会社 | Antistatic polystyrene-based resin composition and molded article thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5360950A (en) * | 1976-11-12 | 1978-05-31 | Asahi Chem Ind Co Ltd | Polymer compositions |
| CA1152669A (en) * | 1979-09-28 | 1983-08-23 | Russell J. Hanna | Latex polymerization process |
-
1979
- 1979-11-12 JP JP14543479A patent/JPS5670043A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5670043A (en) | 1981-06-11 |
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