JP2018087280A - Polypropylene resin-made hollow molding and corrugated tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow molding having excellent flexibility and impact resistance while having the molding cycle shortened by an improved crystallization rate, and a corrugated tube.SOLUTION: A polypropylene resin-made hollow molding is composed of a resin composition containing a polypropylene resin, a phosphoester metal salt-based crystal nucleating agent represented by chemical formula (1), and a metallic soap represented by chemical formula (2).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polypropylene resin hollow molded body and a corrugated tube. In detail, this invention relates to the corrugate tube which consists of a polypropylene resin hollow molded object which is excellent in a softness | flexibility, impact resistance, and productivity, and the said polypropylene resin hollow molded object.

  Since polypropylene resin is relatively inexpensive and has excellent properties, it is used in a wide variety of products such as various molded products such as injection molded products such as protectors and hollow molded products such as corrugated tubes and air ducts. .

  However, polypropylene has a slow crystallization rate, and the product is difficult to solidify, so there is a limit to improving productivity. Specifically, a corrugated tube of a hollow molded product is usually manufactured by continuously molding a molten resin using a mold. At this time, the portion of the molten resin that contacts the mold is cooled by the mold and solidifies at an early stage. However, since the portion of the molten resin that is not in contact with the mold is not cooled by the mold, the molded product is difficult to solidify, and molding takes time.

Therefore, it has been studied to increase the crystallization speed of the polypropylene resin to shorten the molding cycle and improve the productivity. For example, a method of increasing the crystallization speed and improving the productivity by adding an inorganic nucleating agent such as talc, aromatic phosphoric acid ester sodium salt, or aromatic carboxylic acid calcium salt to polypropylene is known. Yes. Patent Document 1 includes a propylene polymer (A), an ethylene polymer (B) having a density of 0.85 to 0.93 g / cm ³ , and an inorganic filler (C), and further cis-1,2- A polypropylene resin composition containing a metal salt (D) such as calcium cyclohexanedicarboxylate is disclosed.

JP 2011-225663 A

  By adding a crystal nucleating agent or talc which is also a filler, it is possible to promote crystallization and improve productivity. However, when crystallization is promoted as in the prior art, mechanical properties such as hardness of the obtained molded product are also improved. Therefore, when a conventional polypropylene resin is used for a hollow molded product such as a corrugated tube that requires flexibility and impact resistance, there is a problem that flexibility and impact resistance are insufficient.

  The present invention has been made in view of the problems of such conventional techniques. An object of the present invention is to provide a polypropylene resin hollow molded article excellent in flexibility and impact resistance while increasing the crystallization speed and shortening the molding cycle, and a corrugate comprising the polypropylene resin hollow molded article. To provide a tube.

（式１中、Ｍはリチウム原子を表し、Ｒ^１は炭素原子数１〜４のアルキレン基を表し、Ｒ^２及びＲ^３はそれぞれ同一又は異なっていてもよく、水素原子又は炭素原子数１〜１２のアルキル基を表し、ｎは１を表す。）

（式２中、Ｒ^４は水素原子又は炭素原子数１０〜３０の脂肪族基を表し、Ｍはリチウム原子又は亜鉛原子を表し、ｎは１又は２を表す。） The polypropylene resin hollow molded body according to the first aspect of the present invention includes a polypropylene resin, a phosphoric acid ester metal salt-based crystal nucleating agent represented by the chemical formula (1), and a metal soap represented by the chemical formula (2). And a resin composition containing The content of the crystal nucleating agent with respect to 100 parts by mass of the polypropylene resin is 0.06 to 5 parts by mass, and the mass ratio of the crystal nucleating agent to the metal soap is 1: 0.5 to 1: 4 (crystal nucleating agent: metal soap. ).

(In formula 1, M represents a lithium atom, R ¹ represents an alkylene group having 1 to 4 carbon atoms, R ² and R ³ may be the same or different, and each represents a hydrogen atom or 1 to carbon atoms. 12 represents an alkyl group, and n represents 1.)

(In formula 2, R ⁴ represents a hydrogen atom or an aliphatic group having 10 to 30 carbon atoms, M represents a lithium atom or a zinc atom, and n represents 1 or 2)

  The corrugated tube according to the second aspect of the present invention comprises the polypropylene resin hollow molded body according to the first aspect.

  The polypropylene resin hollow molded body of the present invention comprises a resin composition in which a specific phosphate metal salt crystal nucleating agent and a specific metal soap are blended in a specific amount with a polypropylene resin. Therefore, it becomes possible to provide a polypropylene resin hollow molded body and corrugated tube excellent in flexibility, impact resistance and productivity.

(A) is the schematic which shows an example of the extrusion molding machine and metal mold | die for manufacturing the corrugated tube which concerns on embodiment of this invention. (B) is sectional drawing which shows the state by which the resin composition was sent in the inside of the said metal mold | die. It is a perspective view which shows an example of the corrugated tube which concerns on embodiment of this invention. In the resin composition of Example 2, it is a graph which shows the relationship between the compounding quantity of a metal soap, and the crystallization start temperature of the said resin composition. It is a graph which shows the relationship between the screw torque of an extrusion molding machine, and the processing time in the case where the mass ratio of a crystal nucleating agent and a metal soap is 1: 4 and 1: 5 regarding the resin composition of Example 2. . It is a graph which shows the relationship between the carbon atom number of the organic acid in a metal soap, and the crystallization start temperature of a resin composition when the kind of metal in a metal soap is changed regarding the resin composition of Example 3.

  Hereinafter, a polypropylene resin hollow molded body and a corrugated tube made of the polypropylene resin hollow molded body according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

  The polypropylene resin hollow molded body according to the present embodiment is composed of a resin composition containing a polypropylene resin, a phosphate metal salt crystal nucleating agent, and a metal soap.

  Polypropylene resin is excellent in tensile strength and impact strength, and has high heat resistance, bending fatigue strength, and electrical insulation. Examples of the polypropylene resin include a propylene homopolymer or a copolymer of propylene and another olefin. Examples of other olefins copolymerizable with propylene include ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1- Examples are α-olefins such as heptene and 3-methyl-1-hexene. The copolymer of propylene and other olefins may be a block copolymer or a random copolymer.

  As described above, the polypropylene resin has a slow crystallization rate, and the product is difficult to solidify. Therefore, the resin composition according to the present embodiment contains a crystal nucleating agent. A crystal nucleating agent is an additive that directly participates in the crystallization process of a crystalline polymer. By adding the crystal nucleating agent, the crystallization of the polymer chain from the molten state is promoted, and the crystallization speed of the resin composition as a whole is increased, improving the productivity during molding and increasing the crystallization speed. This makes it possible to improve the mechanical characteristics.

  Here, regarding the selection of the crystal nucleating agent, the aromatic phosphoric acid ester sodium salt has a high lattice matching with the polypropylene, so that the polypropylene is easily epitaxially grown. Therefore, the crystallinity of polypropylene is increased, and mechanical properties such as hardness can be improved. However, the aromatic phosphate sodium salt tends to agglomerate and is inferior in dispersibility of the crystal nucleating agent, resulting in a slow solidification rate of the entire molded product.

  On the other hand, the lithium phosphate lithium salt is inferior in lattice matching with polypropylene as compared with the sodium salt. However, since the aromatic phosphate lithium salt hardly aggregates inside the polypropylene resin, the dispersibility of the crystal nucleating agent is high, and the solidification rate of the entire molded product can be increased. In addition, when the aromatic phosphate lithium salt is used, it is difficult to improve mechanical properties such as hardness, so that the flexibility of the molded product can be maintained.

化学式（３）中、Ｍはリチウム原子を表し、Ｒ^１は炭素原子数１〜４のアルキレン基を表し、Ｒ^２及びＲ^３はそれぞれ同一又は異なっていてもよく、水素原子又は炭素原子数１〜１２のアルキル基を表し、ｎは１を表す。 From such a viewpoint, it is preferable to use a phosphate ester metal salt-based crystal nucleating agent represented by the following chemical formula (3) as the crystal nucleating agent according to the present embodiment.

In chemical formula (3), M represents a lithium atom, R ¹ represents an alkylene group having 1 to 4 carbon atoms, R ² and R ³ may be the same or different, and each represents a hydrogen atom or 1 carbon atom. Represents an alkyl group of ˜12, and n represents 1.

Examples of the alkylene group having 1 to 4 carbon atoms represented by R ¹ in the chemical formula (3) include a methylene group, an ethylene group, an n-propylene group, and an n-butylene group. Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² and R ³ in the chemical formula (3) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a second butyl group, a third group. A butyl group, isobutyl group, amyl group, isoamyl group, tertiary amyl group, hexyl group, cyclohexyl group, heptyl group, isoheptyl group or tertiary heptyl group is preferred. Among these, the alkyl group represented by R ² and R ³ is preferably a methyl group, a tertiary butyl group, or a tertiary heptyl group.

  The resin composition according to the present embodiment includes a metal soap in order to increase the crystallization speed of the resin composition by highly dispersing a phosphate ester metal salt-based crystal nucleating agent represented by the chemical formula (3) in a polypropylene resin. Contains. Here, when calcium metal soap or magnesium metal soap is added to aromatic phosphate lithium salt, a complex is formed between these metal soap and aromatic phosphate lithium salt, The effect will be hindered. Therefore, in this embodiment, at least one of zinc-based metal soap and lithium-based metal soap is used so as not to inhibit the effect of the crystal nucleating agent.

  Thus, by adding at least one of a zinc-based metal soap and a lithium-based metal soap in addition to the aromatic phosphate lithium salt, the dispersibility of the aromatic phosphate lithium salt in the polypropylene resin is further enhanced. Therefore, by combining the aromatic phosphate lithium salt with at least one of zinc-based metal soap and lithium-based metal soap, it is possible to further increase the solidification rate of the entire molded product.

化学式（４）中、Ｒ^４は水素原子又は炭素原子数１０〜３０の脂肪族基を表し、Ｍはリチウム原子又は亜鉛原子を表し、ｎは１又は２を表す。 The metal soap contained in the resin composition according to this embodiment is preferably a metal soap represented by the chemical formula (4).

In chemical formula (4), R ⁴ represents a hydrogen atom or an aliphatic group having 10 to 30 carbon atoms, M represents a lithium atom or a zinc atom, and n represents 1 or 2.

In the chemical formula (4), the R ⁴ group is an aliphatic group having 1 to 30 carbon atoms, may have a hydroxyl group, or may have a branch. Specific examples of the aliphatic carboxylic acid represented by the chemical formula (4) include capric acid, neodecanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, and nonadecanoic acid. , Arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, melicic acid, tocic acid, Linderic acid, tuzuic acid, palmitoleic acid, petroceric acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid , Γ-linolenic acid, linolenic acid, ricinoleic acid, 12-hydroxystearic acid, naphthenic acid, abietic acid and the like. Of these, stearic acid, 12-hydroxystearic acid, behenic acid, and montanic acid are preferable because of their remarkable effects.

  In the resin composition according to this embodiment, the content of the crystal nucleating agent with respect to 100 parts by mass of the polypropylene resin is preferably 0.06 to 5 parts by mass. When the content of the crystal nucleating agent is less than 0.06 parts by mass, the effect of the crystal nucleating agent on the polypropylene resin becomes insufficient, and the molding speed of the hollow molded body is only slightly improved. On the other hand, when the content of the crystal nucleating agent exceeds 5 parts by mass, the crystal nucleating agent acts as a filler or a foreign substance, so that the flexibility and impact resistance of the obtained hollow molded body are lowered.

  Furthermore, in the resin composition according to this embodiment, the mass ratio of the crystal nucleating agent to the metal soap is preferably 1: 0.5 to 1: 4 (crystal nucleating agent: metal soap). When the mass ratio of the metal soap is less than 0.5, the content of the metal soap is too small, so that the dispersion of the crystal nucleating agent becomes insufficient, and the crystallization speed of the resin composition becomes slow. On the contrary, when the mass ratio of the metal soap exceeds 4, since the content of the metal soap is excessive, the effect of the crystal nucleating agent is hindered and the crystallization speed of the resin composition is slowed down.

  The resin composition according to this embodiment can contain various additives in addition to the above materials. Examples of additives include stabilizers, pigments, extenders, metal deactivators, anti-aging agents, lubricants, reinforcing agents, ultraviolet absorbers, dyes, colorants, antistatic agents, and foaming agents.

  The polypropylene resin hollow molded body according to this embodiment is preferably a hollow body having a hollow inside, and more preferably a substantially cylindrical hollow body. As described above, the hollow molded body according to the present embodiment has a highly dispersed crystal nucleating agent and has a high solidification rate, so that it can be efficiently produced by, for example, a continuous hollow molding method.

  The polypropylene resin hollow molded body according to this embodiment is preferably a corrugated tube. The corrugated tube is a tube that bundles a plurality of electric wires to protect the electric wires, and requires high flexibility in addition to impact resistance. And as above-mentioned, since the hollow molded object which concerns on this embodiment is excellent in heat resistance, electrical insulation, and a softness | flexibility in addition to mechanical strength, it can be used suitably as a corrugated tube.

  Next, the manufacturing method of the polypropylene resin hollow molded body according to this embodiment will be described. The resin composition of the hollow molded body according to the present embodiment can be prepared by melt-kneading the above-mentioned polypropylene resin, a phosphate ester metal salt-based crystal nucleating agent, and metal soap. By melt-kneading these, the crystal nucleating agent is highly dispersed in the melted polypropylene resin due to the effect of the metal soap. Then, by cooling the molten polypropylene resin, crystal nuclei are generated at a supercooling temperature slightly lower than the melting point of the polypropylene resin, and crystals grow around the crystal nuclei. As a result, the polypropylene resin is solidified and a resin composition can be obtained.

  The molding method of the hollow molded body according to the present embodiment is not particularly limited, but can be molded by, for example, a known continuous hollow molding method. Moreover, as an extruder used by the continuous hollow molding method, for example, a single screw extruder or a twin screw extruder can be used.

  In FIG. 1, the manufacturing method of the corrugated tube which concerns on this embodiment is shown, (a) shows an example of the extrusion molding machine and metal mold | die for manufacturing a corrugated tube, (b) is the said metal mold | die. The state in which the molten resin composition was sent into the inside of is shown. The extrusion molding machine in FIG. 1 (a) has a hopper 2, a driving device and a speed reducer 3, a screw 4, a cylinder (barrel) 5, and a heating / cooling device (heater / blower) and a temperature control device (not shown) as main structures. It has. Then, a desired mold (die) 6 is attached to the tip of the cylinder 5 via an adapter to perform molding.

  As shown in FIG. 1, the corrugated tube is preferably manufactured by a continuous hollow molding method. In the continuous hollow molding method, first, an annular tube having an uneven portion in a softened state is extruded from a straight die of the extruder 1. Next, the softened tube is fed into the two-part mold 6. As shown in FIG. 1B, irregularities are alternately formed on the inner surface of the mold 6. Then, the softened tube 7 is fed into the mold 6 and at the same time pressurized with air from the inside of the tube 7 or sucked with vacuum from the outside of the mold 6, thereby bringing the softened tube 7 into the mold. 6. Adhere closely to the inner surface of 6.

  At this time, the outer surface 7 a in contact with the mold 6 in the softened tube 7 is cooled by the mold 6 and solidifies early. On the other hand, the inner surface 7 b that is not in contact with the mold 6 in the tube 7 is not cooled by the mold 6. However, as described above, since the resin composition of the present embodiment has a high crystallization rate, the inner surface 7b of the tube 7 can be solidified at an early stage.

  Then, by taking out the solidified tube 7 from the mold 6, a corrugated tube 10 having an undulating outer surface as shown in FIG. 2 can be obtained.

  Thus, the polypropylene resin hollow molded body according to the present embodiment includes a polypropylene resin, a phosphate metal salt-based crystal nucleating agent represented by the chemical formula (3), and a metal soap represented by the chemical formula (4). It consists of a resin composition containing. And content of the crystal nucleating agent with respect to 100 mass parts of polypropylene resins is 0.06-5 mass parts, and mass ratio of a crystal nucleating agent and a metal soap is 1: 0.5-1: 4 (crystal nucleating agent: Metal soap). Since the hollow molded body of this embodiment uses polypropylene resin as a base resin, it has excellent heat resistance, bending fatigue strength, and electrical insulation in addition to mechanical strength. Further, an aromatic phosphate lithium salt is used as a crystal nucleating agent, and at least one of a zinc-based metal soap and a lithium-based metal soap is added in order to highly disperse the crystal nucleating agent. Therefore, the hollow molded body according to the present embodiment has a high solidification rate and is excellent in flexibility and impact resistance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

  The resin compositions of Examples 1-1 to 1-16 and Comparative Examples 1-1 to 1-25 were prepared by the following method, and the characteristics were evaluated. In the examples and comparative examples, the following compounds were used as raw materials.

（Ｂ２）リン酸エステル金属塩：株式会社ＡＤＥＫＡ 製商品名「アデカスタブ（登録商標）ＮＡ−１１」 リン酸−２，２’−メチレンビス（４，６−ジ−tert−ブチルフェニル）ナトリウム塩（化学式６参照）

（Ｂ３）カルボン酸金属塩：ミリケン・ジャパン社製 商品名「Ｈｙｐｅｒｆｏｒｍ（登録商標）ＨＰＮ−２０Ｅ」 シクロヘキサン−１，２−ジカルボキシル酸カルシウム
（Ｂ４）ソルビトール系誘導体：新日本理化株式会社製 商品名「ゲルオール（登録商標）ＭＤ」 １，３：２，４−ビス−Ｏ−（４−メチルベンジリテン）−Ｄ−ソルビトール
（Ｂ５）タルク：林化成株式会社製 商品名「ミクロンホワイト（登録商標） ＭＷ５０００Ｓ」 含水ケイ酸マグネシウム(4Si0₂・3Mg0・H₂0)
［金属石鹸］
（Ｃ１）ステアリン酸亜鉛：堺化学工業株式会社製 商品名「ＳＺ−Ｐ」
（Ｃ２）ステアリン酸リチウム：堺化学工業株式会社製 商品名「Ｓ−７０００」
（Ｃ３）ステアリン酸マグネシウム：堺化学工業株式会社製 商品名「ＳＭ−Ｐ」
（Ｃ４）ステアリン酸カルシウム：堺化学工業株式会社製 商品名「ＳＣ−Ｐ」 [Polypropylene resin]
(A) Block polypropylene: Product name “Prime Polypro (registered trademark) J356HP” manufactured by Prime Polymer Co., Ltd.
[Crystal nucleating agent]
(B1) Phosphate ester metal salt: ADEKA Corporation, trade name “Adekastab (registered trademark) NA-70” Phosphate-2,2′-methylenebis (4,6-di-tert-butylphenyl) lithium salt (chemical formula 5)

(B2) Phosphate metal salt: trade name “ADEKA STAB (registered trademark) NA-11” manufactured by ADEKA Corporation Phosphate-2,2′-methylenebis (4,6-di-tert-butylphenyl) sodium salt (chemical formula 6)

(B3) Carboxylic acid metal salt: Product name “Hyperform (registered trademark) HPN-20E” manufactured by Milliken Japan Co., Ltd. Cyclohexane-1,2-dicarboxylate (B4) Sorbitol derivative: Product name, manufactured by Shin Nippon Rika Co., Ltd. "Gelol (registered trademark) MD" 1,3: 2,4-bis-O- (4-methylbenzylitene) -D-sorbitol (B5) Talc: Hayashi Kasei Co., Ltd. trade name "Micron White (registered trademark)" MW5000S ”Hydrous magnesium silicate (4Si0 ₂ / 3Mg0 / H ₂ 0)
[Metal soap]
(C1) Zinc stearate: trade name “SZ-P” manufactured by Sakai Chemical Industry Co., Ltd.
(C2) lithium stearate: Sakai Chemical Industry Co., Ltd. trade name “S-7000”
(C3) Magnesium stearate: trade name “SM-P” manufactured by Sakai Chemical Industry Co., Ltd.
(C4) Calcium stearate: trade name “SC-P” manufactured by Sakai Chemical Industry Co., Ltd.

[Preparation of resin composition]
First, Examples 1-1 to 1-16 and Comparative Example 1-1 were carried out by melt-kneading polypropylene resin, crystal nucleating agent, and metal soap with the contents shown in Tables 1 to 4 using a kneader. A resin composition of ˜1-25 was prepared. The contents of the polypropylene resin, the crystal nucleating agent, and the metal soap shown in Tables 1 to 4 are all expressed in “parts by mass”.

  Next, the corrugated tube which consists of each resin composition of the above-mentioned Example 1-1 to 1-16 and Comparative Examples 1-1 to 1-25 was produced using the injection molding machine shown in FIG. The nominal diameter of the corrugated tube was φ25, the inner diameter was 25.0 mm, the outer diameter was 30.0 mm, and the thickness was 0.35 mm.

[Evaluation]
(Crystallization start temperature)
Using DSC (differential scanning calorimeter), the crystallization start temperatures of the resin compositions of Examples 1-1 to 1-16 and Comparative Examples 1-1 to 1-25 were measured. Specifically, a pellet-shaped measurement sample was produced by cutting the resin composition of each example. Next, about 5 mg of the prepared sample was set in the DSC, and once heated to 240 ° C. and allowed to stand at 240 ° C. for 5 minutes, the sample was completely dissolved. Then, it cooled to 25 degreeC on conditions with a speed | rate of 20 degree-C / min, and measured the caloric curve. The crystallization start temperature was the temperature at which the calorimetric curve begins. The measurement result of the crystallization start temperature of each example is shown according to Tables 1-4. The crystallization start temperature is used as a measure of the solidification rate. In particular, a material having a smaller difference between the melting point and the crystallization start temperature (supercooling temperature difference) indicates that the solidification is faster.

(Corrugated tube forming speed)
Using the resin compositions of Examples 1-1 to 1-16 and Comparative Examples 1-1 to 1-25, the production rate when the corrugated tube having the nominal diameter of φ25 is produced is 24 m / min or more. It evaluated as "(circle)" and the case of less than 24 m / min was evaluated as "x". The evaluation result of each example is shown according to Tables 1-4.

(Flexibility)
First, corrugated tubes having a nominal diameter of φ25 according to Examples 1-1 to 1-16 and Comparative Examples 1-1 to 1-25 were cut into a length of 300 mm. Next, one end was fixed while the cut corrugated tube was leveled, and a load of 0.1 N was applied to the end surface of the other end. The deformation amount of the corrugated tube at this time was measured and evaluated as follows.
○: The deformation amount of the corrugated tube when a load is applied is 4.5 mm or more. ×: The deformation amount of the corrugated tube when a load is applied is less than 4.5 mm.

(Impact resistance)
A steel ball having a mass of 500 g was allowed to freely fall from a height of 1 m and collide with a corrugated tube having a nominal diameter of φ25 according to Examples 1-1 to 1-16 and Comparative Examples 1-1 to 1-25. And the change of the external appearance of the corrugated tube was observed visually, and it evaluated as follows.
○: No change in appearance such as deformation or crack in corrugated tube after dropping steel ball ×: There is change in appearance such as deformation or cracking in corrugated tube after dropping steel ball

  As shown in Table 1, in the resin compositions of Examples 1-1 to 1-16 according to the present embodiment, the crystallization start temperature exceeds 131 ° C., and the corrugated tube forming speed is also good. I understand. Furthermore, it turns out that the corrugated tube which consists of a resin composition of Examples 1-1 to 1-16 is excellent also in a softness | flexibility and impact resistance.

  On the other hand, it can be seen that the resin composition of Comparative Example 1-1 consisting only of polypropylene resin has a crystallization start temperature of less than 115 ° C., and the corrugated tube molding speed is deteriorated. Moreover, even if it uses the same crystal nucleating agent as an Example from Comparative Examples 1-2 to 1-4, when a metal soap is not contained, it turns out that a corrugated tube shaping | molding speed | rate is inadequate. From Comparative Example 1-5, it can be seen that the flexibility and impact resistance of the corrugated tube are deteriorated when the same crystal nucleating agent as in Example is added excessively without containing metal soap.

  From Comparative Examples 1-6 to 1-9, when metal phosphate is not contained and phosphoric acid ester sodium salt is used as the crystal nucleating agent, the corrugated tube forming speed or flexibility is adjusted even if the addition amount is adjusted. It can also be seen that the impact resistance deteriorates.

  From Comparative Examples 1-10 to 1-13, when a carboxylic acid metal salt was used as a crystal nucleating agent without containing metal soap, the corrugated tube forming speed or flexibility and It can be seen that the impact resistance deteriorates.

  From Comparative Examples 1-14 to 1-17, when a sorbitol-based derivative was used as a crystal nucleating agent without containing metal soap, the corrugated tube forming speed, flexibility, and resistance It turns out that impact property deteriorates.

  From Comparative Examples 1-18 to 1-19, when talc was used as the crystal nucleating agent without containing metal soap, the corrugated tube forming speed, flexibility, and impact resistance were adjusted even when the addition amount was adjusted. It turns out that gets worse.

  From Examples 1-1 and 1-2 and Comparative Example 1-20, when the mass ratio of the crystal nucleating agent and the metal soap does not satisfy 1: 0.5 to 1: 4, and the metal soap is too small It can be seen that the dispersibility of the crystal nucleating agent becomes insufficient and the corrugated tube forming speed is deteriorated.

  From Examples 1-7 and 1-8 and Comparative Example 1-21, the mass ratio of the crystal nucleating agent to the metal soap does not satisfy 1: 0.5 to 1: 4, and the metal soap is excessive. It can be seen that the crystallization start temperature decreases and the corrugated tube forming speed deteriorates.

  From Examples 1-13 and 1-14 and Comparative Example 1-22, when the mass ratio of the crystal nucleating agent to the metal soap does not satisfy 1: 0.5 to 1: 4, and the metal soap is too small It can be seen that the dispersibility of the crystal nucleating agent becomes insufficient and the corrugated tube forming speed is deteriorated.

  From Examples 1-15 and 1-16 and Comparative Example 1-23, even when the mass ratio of the crystal nucleating agent and the metal soap does not satisfy 1: 0.5 to 1: 4, and the metal soap is excessive. It can be seen that the crystallization start temperature decreases and the corrugated tube forming speed deteriorates.

  From Comparative Examples 1-24 and 1-25, when magnesium stearate and calcium stearate are used as the metal soap, the dispersibility of the crystal nucleating agent is not improved. Therefore, it turns out that crystallization start temperature falls and a corrugated tube shaping | molding speed | rate deteriorates.

  In Example 2, the difference in the crystallization start temperature was examined by changing the compounding ratio of the crystal nucleating agent and the metal soap.

  Specifically, first, a resin composition of Example 2 was prepared by melt-kneading a polypropylene resin, a crystal nucleating agent, and a metal soap using a kneader. In addition, the polypropylene resin used the same thing as Example 1, the crystal nucleating agent used the (B2) phosphate ester metal salt of Example 1, and the metal soap used the behenate zinc. The amount added was 0.2 parts by mass of the crystal nucleating agent with respect to 100 parts by mass of the polypropylene resin. The amount of metal soap added was adjusted as shown in FIG. 3 to prepare a plurality of resin compositions.

  Then, the crystallization start temperature of each resin composition was measured in the same manner as in Example 1. FIG. 3 shows the relationship between the amount of metal soap blended in each resin composition and the crystallization start temperature.

  As shown in FIG. 3, when the mass ratio of the crystal nucleating agent and the metal soap is in the range of 1: 0.5 to 1: 4, the crystallization start temperature exceeds 131 ° C. It turns out that a shaping | molding speed is favorable similarly to -1 to 1-16. On the other hand, when the mass ratio of the crystal nucleating agent and the metal soap is outside the range of 1: 0.5 to 1: 4, it can be seen that the crystallization start temperature is lowered and the molding speed is deteriorated.

  Here, in FIG. 4, regarding the resin composition of Example 2, the screw torque and processing time of the extruder in the case where the mass ratio of the crystal nucleating agent and the metal soap is 1: 4 and 1: 5, Shows the relationship. As shown in FIG. 4, when the mass ratio of the crystal nucleating agent and the metal soap is 1: 4, the screw torque is stably reduced after 100 seconds, and the corrugated tube molding process is efficiently performed. Can do.

  On the other hand, when the mass ratio of the crystal nucleating agent and the metal soap is 1: 5, it can be seen that the screw torque becomes unstable after 100 seconds. That is, when the metal soap is excessively added, the metal soap melts and liquefies in the vicinity of the processing temperature, so that the ratio of the liquid component in the resin composition increases. As a result, since the screw torque of the extruder becomes unstable, it becomes difficult to form the corrugated tube.

  Thus, from the viewpoint of the moldability of the corrugated tube, the mass ratio between the crystal nucleating agent and the metal soap is preferably in the range of 1: 0.5 to 1: 4.

In Example 3, the difference in crystallization start temperature was examined by changing the type of metal soap. In this example, the same polypropylene resin as in Example 1 was used, and (B2) phosphate ester metal salt of Example 1 was used as the crystal nucleating agent. And the following were used as metal soap. The amount added was 0.2 parts by mass of the crystal nucleating agent and 0.5 parts by mass of the metal soap with respect to 100 parts by mass of the polypropylene resin.
-Metal soap with 18 carbon atoms: lithium stearate, calcium stearate, zinc stearate-Metal soap with 22 carbon atoms: lithium behenate, calcium behenate, zinc behenate-Metal soap with 28 carbon atoms : Lithium montanate, calcium montanate, zinc montanate

  And the resin composition of this example was prepared by melt-kneading the above-mentioned polypropylene resin, crystal nucleating agent, and metal soap using a kneader. Furthermore, the crystallization start temperature of each resin composition was measured in the same manner as in Example 1. FIG. 5 shows the relationship between the number of carbon atoms of the organic acid in the metal soap and the crystallization start temperature in each resin composition.

  As shown in FIG. 5, by using a lithium salt and a zinc salt of an aliphatic organic acid as a metal soap, it becomes possible to increase the dispersibility of the crystal nucleating agent and increase the crystallization start temperature. On the other hand, it can be seen that a calcium salt of an aliphatic organic acid as a metal soap has an insufficient increase in the crystallization start temperature and does not improve the molding speed.

  As mentioned above, although this invention was demonstrated by the Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention. In addition, the corrugated tube which concerns on embodiment of this invention is not limited to a bellows-shaped thing as shown in FIG. 2, For example, the bellows-shaped part and the cylindrical straight part are integrally molded, Also good.

  10 Corrugated tube

Claims (2)

Polypropylene resin,
A phosphate ester metal salt-based crystal nucleating agent represented by the chemical formula (1);
A metal soap represented by the chemical formula (2),
A resin composition containing
The content of the crystal nucleating agent with respect to 100 parts by mass of the polypropylene resin is 0.06 to 5 parts by mass, and the mass ratio of the crystal nucleating agent and the metal soap is 1: 0.5 to 1: 4 (crystal nuclei). A hollow molded product made of polypropylene resin that is an agent: metal soap).

(In formula 1, M represents a lithium atom, R ¹ represents an alkylene group having 1 to 4 carbon atoms, R ² and R ³ may be the same or different, and each represents a hydrogen atom or 1 to carbon atoms. 12 represents an alkyl group, and n represents 1.)

(In formula 2, R ⁴ represents a hydrogen atom or an aliphatic group having 10 to 30 carbon atoms, M represents a lithium atom or a zinc atom, and n represents 1 or 2)   A corrugated tube comprising the polypropylene resin hollow molded body according to claim 1.

Images