【発明の詳細な説明】
本発明は射出成形用ポリブテン―１組成物に関
する。
ポリブテン―１（以下PB―１と呼ぶことがあ
る）は、耐クリープ性、耐環境応力亀裂性に優
れ、且つ柔軟性、耐衝撃性、耐熱性を備えてお
り、パイプやフイルムに成形加工して一部給水
用、給湯用パイプや包装用フイルムとして使用さ
れている。ところが意外なことにかかるPB―１
を射出成形すると、PB―１本来の特徴である耐
衝撃性や耐クリープ性を有せず、少変形によつて
簡単に破断し、全く実用に適さないことが分かつ
た。
かかる状況に鑑み、本発明者らは、剛性、引張
強度、衝撃強度、耐クリープ性等の機械的強度に
優れたポリブテン―１の射出成形品を得ることを
目的として種々検討した結果、特定の極限粘度
〔η〕を有するPB―１にポリプロピレンを少量ブ
レンドした組成物を用いることにより、上記目的
を達成できることが分かり、本発明に到達した。
すなわち本発明は、極限粘度〔η〕が1.5ない
し3.5dl／ｇであるポリブテン―１（Ａ）：100重量
部と、極限粘度〔η〕が0.05ないし5.0dl／ｇで
あるポリプロピレン(B)：ないし30重量部とからな
ることを特徴とする引張強度、衝撃強度、耐クリ
ープ性等の機械的強度に優れた射出成形用ポリブ
テン―１組成物を提供するものである。
本発明に用いるPB―１(A)は、極限粘度〔η〕
（デカリン溶媒、135℃での値）が1.5ないし3.5
dl／ｇ、好ましくは2.0ないし3.2dl／ｇの範囲の
ものである。〔η〕が1.5dl／ｇ未満のものは、機
械的強度が低く、また〔η〕が3.5dl／ｇを越え
るものは、ポリプロピレンを混合しても、射出成
形すると、射出成形品の表層に脆弱層が生じ、射
出成形品が変形を受けた場合に、該脆弱層がノツ
チ効果として働き、機械的強度に劣つた射出成形
品しか得られない。該PB―１(A)は、ブテン―１
をチーグラー触媒系で重合することにより得られ
る結晶性の樹脂であり、結晶性を有し且つPB―
１の性質を損わない限り、他のα―オレフイン、
例えばエチレン、プロピレン等を少量含んでいて
もよい。又、本発明に用いるPB―１(A)は、極限
粘度〔η〕が上記範囲内であればよく、例えば極
限粘度〔η〕が大きいものと、小さいものとのブ
レンド（分子量分布が広い）であつてもよい。
本発明の方法に用いるポリプロピレン(B)は、プ
ロピレンをチーグラー触媒系で重合することによ
り得られる結晶性の樹脂であり、結晶性を有し且
つポリプロピレンの性質を損わない限り、他のα
―オレフイン、例えばエチレン、１―ブテン、１
―ヘキセン等を少量含んでてもよい。該ポリプロ
ピレン(B)としては極限粘度〔η〕（デカリン溶媒、
135℃での値）が0.05ないし5.0dl／ｇ、好適には
0.1ないし4.0dl／ｇの範囲のものが前記PB―１(A)
の射出成形性及び機械的強度の低下を招かない。
本発明の射出成形用ポリブテン―１組成物は、
前記ポリブテン―１(A)：100重量部とポリプロピ
レン(B)１ないし30重量部、好ましくは３ないし20
重量部とから構成される。
ポリプロピレン(B)の量が１重量部未満では、ポ
リブテン―１の射出成形性が改良されず、また30
重量部を越えると、ポリブテン―１の本来の特徴
である衝撃強度、耐クリープ性等の機械的強度が
損われる。
本発明の射出成形用ポリブテン―１組成物を得
るには、前記ポリブテン―１(A)とポリプロピレン
(B)とを前記範囲でヘンシエルミキサー、Ｖ―ブレ
ンダー、リボンブレンダー、タンブラーブレンダ
ーで混合する方法、あるいは混合後、更に単軸押
出機、多軸押出機、バンバリーミキサー、ニーダ
ー等で溶融混練後、造粒あるいは粉砕する方法を
採用することができるが、重合時にプロピレンを
前重合して所定量のポリプロピレンを重合した
後、引き続きブテン―１を所定量重合してポリプ
ロピレンとポリブテン―１とからなる組成物を製
造する方法も採り得る。
本発明の射出成形用ポリブテン―１組成物に
は、前記必須の二成分に加えて、通常ポリオレフ
インに添加して使用される各種配合剤、例えば耐
候安定剤、耐熱安定剤、滑剤、核剤、顔料、染
料、ガラス繊維、炭素繊維、タルク、炭酸カルシ
ウム等の無機補強材、無機充填剤、発泡剤等を本
発明の目的を損わない範囲で添加しておいてもよ
い。
本発明の射出成形用ポリブテン―１組成物は、
引張強度、衝撃強度、耐クリープ性等の機械的強
度に優れ、且つポリブテン―１本来の特徴である
耐環境応力亀裂性、柔軟性をも有するので、工業
用部品、パイプ等の継手部、電気器具部品をはじ
め日用品等のあらゆる分野に用いることができ
る。
次に実施例を挙げて本発明を更に詳しく説明す
るが、本発明はその要旨を越えない限りこれらの
実施例に何ら制約されるものではない。
実施例 １
三塩化チタンを用いてチーグラー重合により製
造した極限粘度〔η〕＝3.1dl／ｇのポリブテン―
1100重量部に同じくチーグラー重合により製造さ
れた極限粘度〔η〕＝2.2dl／ｇのポリプロピレン
25重量部に酸化防止剤を加え、30mmφの一軸押出
機を用いて、樹脂温度200℃の条件で混練造粒し
た。上記組成物を16オンスの射出ユニツトを備え
た型締圧140トンで、120mm×130mm、厚さ４mmの
角板成形用金型を取付けた射出成形機を用い、樹
脂温度250℃、射出圧を1000Kg／cm2に設定し成形
した。得られた成形角板を以下の方法により評価
した。
引張特性：ASTM Ｄ 638に準拠し、ASTM4
号ダンベルを用い、降伏点応力、破断点抗
張力（Kg／cm2）と破断点伸び（％）を測定
した。
Izod衝撃強度（Kg・cm／cm）：ASTM Ｄ 256に
準拠し、角板の中心部から射出方向が長辺
になるように短冊片を打ち抜き、ノツチを
入れ０℃で測定した。
耐クリープ性（時間）：ASTM Ｄ 2990に準拠
し、引張クリープ性を評価した。試験片は
ASTM4号ダンベルを用い、角板の中心か
ら射出方向が引張り方向となるように打ち
抜いた。試験温度100℃、荷重20Kgとし、
破断するか25％延伸されるまでの時間を測
定した。
結果を第１表に示す。
実施例 ２
三塩化チタンを用いてチーグラー重合により製
造した極限粘度〔η〕＝2.3dl／ｇのポリブテン―
1100重量部に同じくチーグラー重合により製造さ
れた極限粘度〔η〕＝0.8dl／ｇのポリプロピレン
10重量部に酸化防止剤を加え、30mmφの一軸押出
機を用いて、樹脂温度200℃の条件で混練造粒し
た。上記組成物を実施例１と同様の方法で成形、
評価した。結果を第１表に示す。
実施例 ３
三塩化チタンを用いてチーグラー重合により製
造した極限粘度〔η〕＝1.8dl／ｇのポリブテン―
1100重量部に同じくチーグラー重合により製造さ
れた極限粘度〔η〕＝0.5dl／ｇのポリプロピレン
５重量部を実施例１と同様の手順で混練造粒、射
出成形後、物性評価した。結果を第１表に示す。
比較例 １
三塩化チタンを用いてチーグラー重合により製
造した極限粘度〔η〕＝3.9dl／ｇのポリブテン―
１に酸化防止剤を加え、30mmφの一軸押出機を用
いて、樹脂温度200℃の条件で混練造粒した。上
記ポリブテン―１を実施例１と同様の方法で成
形、評価した。結果を第１表に示す。
比較例 ２
比較例１と同じポリブテン―1100重量部に実施
例１と同じポリプロピレン25重量部を実施例１と
同様の手順で混練造粒、射出成形後、物性評価し
た。結果を第１表に示す。
比較例 ３
実施例２と同じポリブテン―１を比較例１と同
様の手順で混練造粒、射出成形後、物性評価し
た。結果を第１表に示す。
比較例 ４
実施例２と同じポリブテン―1100重量部に実施
例２と同じポリプロピレン65重量部を実施例１と
同等の手順で混練造粒、射出成形後、物性評価し
た。結果を第１表に示す。
比較例 ５
三塩化チタンを用いてチーグラー重合により製
造した極限粘度〔η〕＝1.0dl／ｇのポリブテン―
1100重量部に同じくチーグラー重合により製造さ
れた極限粘度〔η〕＝0.4dl／ｇのポリプロピレン
10重量部を実施例１と同様の手順で混練造粒、射
出成形後、物性評価した。結果を第１表に示す。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polybutene-1 compositions for injection molding. Polybutene-1 (hereinafter sometimes referred to as PB-1) has excellent creep resistance and environmental stress cracking resistance, as well as flexibility, impact resistance, and heat resistance, and can be formed into pipes and films. Some of these are used for water supply, hot water supply pipes, and packaging films. However, surprisingly, PB-1
When injection molded, it was found that it did not have the impact resistance and creep resistance that are the original characteristics of PB-1, and easily broke due to slight deformation, making it completely unsuitable for practical use. In view of this situation, the present inventors conducted various studies with the aim of obtaining polybutene-1 injection molded products with excellent mechanical strength such as rigidity, tensile strength, impact strength, and creep resistance. It has been found that the above object can be achieved by using a composition in which a small amount of polypropylene is blended with PB-1 having an intrinsic viscosity [η], and the present invention has been achieved. That is, the present invention uses 100 parts by weight of polybutene-1 (A) having an intrinsic viscosity [η] of 1.5 to 3.5 dl/g, and polypropylene (B) having an intrinsic viscosity [η] of 0.05 to 5.0 dl/g: The object of the present invention is to provide a polybutene-1 composition for injection molding, which has excellent mechanical strength such as tensile strength, impact strength, and creep resistance, and is characterized by comprising from 30 parts by weight to 30 parts by weight. PB-1(A) used in the present invention has an intrinsic viscosity [η]
(Decalin solvent, value at 135℃) is 1.5 to 3.5
dl/g, preferably in the range of 2.0 to 3.2 dl/g. If [η] is less than 1.5 dl/g, the mechanical strength is low, and if [η] is more than 3.5 dl/g, even if polypropylene is mixed, it will not form on the surface layer of the injection molded product when injection molded. When a brittle layer is formed and the injection molded product is deformed, the brittle layer acts as a notch effect, resulting in an injection molded product with poor mechanical strength. The PB-1(A) is butene-1
It is a crystalline resin obtained by polymerizing with a Ziegler catalyst system, and has crystallinity and PB-
Other α-olefins, as long as they do not impair the properties of 1.
For example, it may contain a small amount of ethylene, propylene, etc. Further, PB-1(A) used in the present invention may have an intrinsic viscosity [η] within the above range, for example, a blend of one with a high intrinsic viscosity and one with a small intrinsic viscosity (with a wide molecular weight distribution). It may be. The polypropylene (B) used in the method of the present invention is a crystalline resin obtained by polymerizing propylene with a Ziegler catalyst system, and other α
-Olefins, such as ethylene, 1-butene, 1
- May contain small amounts of hexene, etc. The polypropylene (B) has an intrinsic viscosity [η] (decalin solvent,
value at 135°C) from 0.05 to 5.0 dl/g, preferably
The above PB-1(A) is in the range of 0.1 to 4.0 dl/g.
No deterioration in injection moldability or mechanical strength. The polybutene-1 composition for injection molding of the present invention is
Said polybutene-1 (A): 100 parts by weight and polypropylene (B) 1 to 30 parts by weight, preferably 3 to 20 parts by weight
It consists of parts by weight. If the amount of polypropylene (B) is less than 1 part by weight, the injection moldability of polybutene-1 will not be improved;
If the amount exceeds the weight part, mechanical strengths such as impact strength and creep resistance, which are the original characteristics of polybutene-1, will be impaired. In order to obtain the polybutene-1 composition for injection molding of the present invention, the polybutene-1 (A) and polypropylene
(B) in the above range using a Henschel mixer, V-blender, ribbon blender, tumbler blender, or after mixing, and then melt-kneading using a single-screw extruder, multi-screw extruder, Banbury mixer, kneader, etc. However, during polymerization, propylene is prepolymerized to polymerize a predetermined amount of polypropylene, and then a predetermined amount of butene-1 is polymerized to form polypropylene and polybutene-1. A method of manufacturing a composition may also be adopted. In addition to the above-mentioned two essential components, the polybutene-1 composition for injection molding of the present invention includes various compounding agents that are usually added to polyolefins, such as weathering stabilizers, heat stabilizers, lubricants, nucleating agents, Pigments, dyes, glass fibers, carbon fibers, talc, inorganic reinforcing materials such as calcium carbonate, inorganic fillers, blowing agents, etc. may be added to the extent that they do not impair the purpose of the present invention. The polybutene-1 composition for injection molding of the present invention is
It has excellent mechanical strength such as tensile strength, impact strength, and creep resistance, and also has environmental stress cracking resistance and flexibility, which are the original characteristics of polybutene-1, so it is suitable for industrial parts, joints of pipes, etc. It can be used in all fields including appliance parts and daily necessities. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded. Example 1 Polybutene with intrinsic viscosity [η] = 3.1 dl/g produced by Ziegler polymerization using titanium trichloride.
1100 parts by weight of polypropylene with an intrinsic viscosity [η] = 2.2 dl/g also produced by Ziegler polymerization
An antioxidant was added to 25 parts by weight, and the mixture was kneaded and granulated using a 30 mmφ single screw extruder at a resin temperature of 200°C. The above composition was heated at a resin temperature of 250°C and an injection pressure using an injection molding machine equipped with a 16 ounce injection unit, a mold clamping pressure of 140 tons, a square plate mold of 120 mm x 130 mm, and a thickness of 4 mm. It was molded at a pressure of 1000Kg/cm 2 . The obtained molded square plate was evaluated by the following method. Tensile properties: According to ASTM D 638, ASTM4
Using dumbbells, the yield stress, tensile strength at break (Kg/cm 2 ), and elongation at break (%) were measured. Izod impact strength (Kg·cm/cm): In accordance with ASTM D 256, a strip was punched out from the center of a square plate so that the long side was in the injection direction, a notch was inserted, and the measurement was performed at 0°C. Creep resistance (hours): Tensile creep resistance was evaluated in accordance with ASTM D 2990. The test piece is
Using an ASTM No. 4 dumbbell, a square plate was punched out from the center so that the injection direction was the tensile direction. The test temperature was 100℃ and the load was 20Kg.
The time until breakage or 25% stretching was measured. The results are shown in Table 1. Example 2 Polybutene with intrinsic viscosity [η] = 2.3 dl/g produced by Ziegler polymerization using titanium trichloride.
1100 parts by weight of polypropylene with an intrinsic viscosity [η] = 0.8 dl/g also produced by Ziegler polymerization
An antioxidant was added to 10 parts by weight, and the mixture was kneaded and granulated using a 30 mmφ single screw extruder at a resin temperature of 200°C. Molding the above composition in the same manner as in Example 1,
evaluated. The results are shown in Table 1. Example 3 Polybutene with intrinsic viscosity [η] = 1.8 dl/g produced by Ziegler polymerization using titanium trichloride.
1,100 parts by weight of polypropylene having an intrinsic viscosity [η] of 0.5 dl/g, which was also produced by Ziegler polymerization, was kneaded, granulated, and injection molded in the same manner as in Example 1, and then the physical properties were evaluated. The results are shown in Table 1. Comparative Example 1 Polybutene with intrinsic viscosity [η] = 3.9 dl/g produced by Ziegler polymerization using titanium trichloride.
An antioxidant was added to 1, and the mixture was kneaded and granulated using a 30 mmφ single screw extruder at a resin temperature of 200°C. The above polybutene-1 was molded and evaluated in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 2 1100 parts by weight of the same polybutene as in Comparative Example 1 and 25 parts by weight of the same polypropylene as in Example 1 were kneaded, granulated and injection molded in the same manner as in Example 1, and then the physical properties were evaluated. The results are shown in Table 1. Comparative Example 3 The same polybutene-1 as in Example 2 was kneaded, granulated, and injection molded in the same manner as in Comparative Example 1, and its physical properties were evaluated. The results are shown in Table 1. Comparative Example 4 1100 parts by weight of the same polybutene as in Example 2 and 65 parts by weight of the same polypropylene as in Example 2 were kneaded, granulated and injection molded in the same manner as in Example 1, and the physical properties were evaluated. The results are shown in Table 1. Comparative Example 5 Polybutene with intrinsic viscosity [η] = 1.0 dl/g produced by Ziegler polymerization using titanium trichloride.
1100 parts by weight of polypropylene with intrinsic viscosity [η] = 0.4 dl/g also produced by Ziegler polymerization
10 parts by weight was kneaded, granulated and injection molded in the same manner as in Example 1, and the physical properties were evaluated. The results are shown in Table 1. 【table】