JP2000254959A - Multilayered hollow molded container and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered hollow molded container made of a resin improved in transparency, impact resistance and flexibility and a method for producing the same. SOLUTION: A multilayered hollow molded container comprising two or more layers has at least one layer comprising a propylene type block copolymer containing 5 wt.% or more of a 20 deg.C xylene soluble portion (CXS portion) and characterized by that a portion (CXIS portion) excepting the CXS portion has a max. fusion peak temp.(Tm) of 130-155 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer hollow molded container and a method for producing the same. More particularly, it relates to a multilayer hollow molded container excellent in transparency, low-temperature impact resistance and flexibility, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a plastics container, a hollow molding method has been widely used. Above all,
Polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE) and polypropylene (PP) make use of
It is widely used as a container for beverages, detergents and shampoos, chemicals, and industrial use.

[0003] In recent years, the use of PET bottles by the biaxial stretch blow molding method, which is excellent in transparency, strength and uniform thickness for food and beverages, has been remarkably widespread. In view of the fact that they are high, and are inferior in flexibility and recyclability, more preferable materials are required. In addition, hollow containers made by direct blow molding of PET have higher material costs,
There are many problems such as narrow molding temperature range and poor moldability. On the other hand, polyvinyl chloride has an advantage that the material cost is lower than PET, but has been shunned by recent environmental awareness and its use has been refrained.

[0004] Polypropylene has attracted attention as a resin that can meet such needs. As general properties of polypropylene, propylene homopolymer is excellent in transparency, but is inferior in impact resistance and flexibility.Propylene block copolymer is excellent in impact resistance but is inferior in transparency and flexibility,
Since the propylene random copolymer is excellent in transparency and flexibility, but inferior in impact resistance, it has been difficult to satisfy all the characteristics of the propylene random copolymer with a specific type of polypropylene.

[0005] The surface decoration of the hollow molded container is performed by silk screen printing, shrink labeling, label sticking, or the like. For labeling, a paper label was applied by a labeling machine after molding the hollow container. Recently, hollow molded containers with an in-mold label have begun to spread for the purpose of simplifying the process and improving the appearance by integrating the hollow molded container and the label. This hollow molded container is formed by setting a label in a mold in advance and then clamping and blowing a parison. However, this hollow molded container has a problem that the notch is formed at the end of the label, so that the container is easily broken from the end of the label when dropped. For this reason, it is necessary to use a resin excellent in impact resistance for the hollow molded container with the in-mold label.

[0006] As a measure for improving the hollow molded container by the direct blow molding method, for example, an attempt is made to add a nucleating agent when it is desired to improve transparency, and to add an elastomer component when it is desired to improve the impact resistance at a low temperature. Is often done. JP-A-57-34924 discloses a hollow molded container obtained by adding a sorbitol-based nucleating agent to a propylene random copolymer as an improvement in transparency. However, this container is not preferable because the peculiar odor of the nucleating agent permeates from the hollow molded container and moves to the contents.

[0007] Japanese Patent Application Laid-Open No. 61-987 discloses an improvement in impact resistance.
No. 56 discloses a hollow molded container made of a composition of a soft elastomer such as polypropylene, linear low-density polyethylene, and an ethylene-α-olefin copolymer. There was a problem that the property was not sufficient, and it was easily broken especially in a low temperature drop test. In order to further improve the impact resistance at low temperatures, there is a means for increasing the amount of the elastomer component, but there has been a problem that the transparency of the container is reduced and the commercial value is impaired.

Further, as a measure for improving a hollow molded container by a biaxial stretch blow molding method, for example, Japanese Patent Publication No. Hei 4-3727 discloses an ethylene unit content of 1 to 6% by weight and a melt flow index of 4 to 50 g / m. A stretch blow container is disclosed by performing a preform molding by injection molding, a preliminary blow, and a stretch blow molding using a propylene-ethylene random copolymer for 10 minutes. However, this container is not yet sufficient in terms of transparency and low-temperature impact resistance, and there is room for improvement in uneven thickness of the container.

Japanese Patent Application Laid-Open No. 9-52278 discloses that
A melt flow index of 3 to 40 g / 10 min, a comonomer content of more than 6 wt%, a random flow of propylene of 15 wt% or less and α-olefin having 2 to 10 carbon atoms.
A container is disclosed in which the copolymer is biaxially stretch blow-molded eight times or more in length and width. This container has excellent transparency,
The impact resistance has not yet reached a satisfactory level.

JP-A-6-270355 discloses that a melt flow rate containing 0.5 to 3.0% by weight of ethylene and 500 to 2000 ppm of a nucleating agent is 40.0 g / 10 A multi-layer plastic container is disclosed in which a propylene random copolymer of not more than one minute is used as the outermost layer and one or more olefin resin layers are provided inside the outermost layer. Although this container is excellent in gloss, both transparency and impact resistance have not reached a satisfactory level.

[0011]

SUMMARY OF THE INVENTION In a polypropylene-based multilayer hollow molded container, transparency, impact resistance at low temperature,
These techniques are not yet satisfactory for improving flexibility together, and further improvements have been desired.

An object of the present invention is to provide a resin-made multilayer hollow molded container having improved transparency, impact resistance and flexibility, and a method for producing the same.

[0013]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies in order to obtain a resin multilayer hollow molded container having improved transparency, impact resistance and flexibility. The present inventors have found that the object of the present invention can be achieved by using a specific polypropylene, and have reached the present invention.

That is, the present invention relates to a multilayer hollow molded container comprising two or more layers, wherein the xylene-soluble portion (CX
(CXIS part) excluding the CXS part and having a maximum melting peak temperature (Tm) of 13%.
A multilayer hollow molded container having at least one layer made of a propylene-based block copolymer at 0 to 155 ° C. Further, the present invention is a method for producing a multilayer hollow molded container, characterized in that the multilayer hollow molded container is produced by a direct blow molding method or a biaxial stretch blow molding method. Hereinafter, the present invention will be described in detail.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The multilayer hollow molded container of the present invention
It contains 5% by weight or more, preferably 10 to 50% by weight, of a xylene-soluble portion (CXS portion) at 0 ° C., and the portion excluding the CXS portion (CXIS portion) has a maximum melting peak temperature (Tm) of 1%.
A layer comprising a propylene-based block copolymer at 30 to 155 ° C, preferably 130 to 145 ° C, has at least one layer.
It is a multilayer hollow molded container having layers. The maximum melting peak temperature (Tm) is measured with a differential scanning calorimeter (DSC).
If the xylene-soluble portion (CXS portion) at 20 ° C. of the propylene-based block copolymer is less than 5% by weight, the flexibility of the multilayer blow-molded container is not preferable. If the maximum melting peak temperature (Tm) in the DSC of the CXIS part of the propylene-based block copolymer is lower than 130 ° C., the container becomes too soft and thus inferior in flexibility. Poor impact resistance. The propylene-based block copolymer is produced from the following two steps.

The propylene block copolymer used in the present invention has a content of a repeating unit derived from ethylene in the first step (hereinafter referred to as "ethylene unit") of 1.5 to 6.0% by weight. Of the propylene-ethylene copolymer part (A component) of 40 to 85% by weight of the total polymerization amount (the total amount of the A component and the following B component), and then the ethylene unit content in the second step is 7 to 17%. A block copolymer obtained by producing 15 to 60% by weight of a propylene-ethylene copolymer portion (B component) in an amount of 15 to 60% by weight of the total polymerization amount (the total amount of the A component and the B component); Intrinsic viscosity ([η]
B) is 2 to 5 dl / g, intrinsic viscosity of component B ([η] B)
And the intrinsic viscosity ([η] A) of component A ([η] B /
[Η] A) is preferably a propylene-based block copolymer having a ratio of 0.5 to 1.8.

The propylene block copolymer used in the present invention comprises a propylene-ethylene copolymer portion in the first step and a propylene-ethylene copolymer portion having a different ethylene unit content in the second step. Is a copolymer obtained by sequential polymerization of a copolymer and a block copolymer, rather than a typical block copolymer in which one terminal of a copolymer and another terminal of a copolymer are connected by a bond. It is. Further, the propylene-based block copolymer is also called an impact-resistant propylene copolymer.

The ratio of the propylene-ethylene copolymer portion (component A) polymerized in the first step and the propylene-ethylene copolymer portion (component B) polymerized in the second step is A
The component is 40 to 85% by weight, preferably 55 to 83% by weight, and the B component is 60 to 15% by weight, preferably 45 to 17%.
% By weight.

In particular, when used in a multilayer blow-molded container, the proportion of the component B is more preferably 17 to 27% by weight.

Producing a propylene-ethylene copolymer portion in which the B component is 17 to 27% by weight in the polymerization step to obtain a propylene-ethylene copolymer portion in which the B component particularly ranges from 17 to 27% by weight. It is also possible to prepare a propylene-ethylene copolymer portion having a B component ratio of 27 to 60% by weight by polymerization, and to add only the A component during melt-kneading to adjust the B component ratio. It is possible.

The ethylene unit content of the ethylene-propylene copolymer portion (component A) polymerized in the first step is preferably 1.5 to 6.0% by weight. In particular, it is more preferable that the content of the ethylene unit is 2.5 to 4.5% by weight from the viewpoint of the balance between flexibility and heat resistance.

The ethylene unit content of the propylene-ethylene copolymer part (component B) polymerized in the second step is 7
~ 17% by weight is preferred. In particular, the content of the ethylene unit of 8 to 12% by weight is more preferable from the viewpoint of the balance between the impact resistance at low temperatures and the transparency.

The content of the ethylene unit is measured by a ¹³ C-NMR method according to a method described on page 616 of a polymer handbook (1995, published by Kinokuniya Bookstore). The ethylene unit content (EA) of the component A is analyzed by sampling the copolymer after the completion of the polymerization in the first step. The content of the ethylene unit of the B component (EB) is determined by sampling the block copolymer after the completion of the polymerization in the second step,
The ethylene unit content (EAB) of the block copolymer was analyzed, and the ratio of the component A (PA) and the ratio of the component B (P
B) is obtained from the following equation. EA × PA / 100 + EB × PB / 100 = EAB EB = (EAB−EA × PA / 100) × 100 / PB

The intrinsic viscosity ([η] B) of the component B of the propylene block copolymer used in the present invention is 2 to 5 dl / g,
The ratio ([η] B / [η] A) between the intrinsic viscosity of component B ([η] B) and the intrinsic viscosity of component A ([η] A) is 0.5 to
1.8 is preferred from the viewpoint of transparency. In particular,
It is more preferable that the intrinsic viscosity ([η] B) of the B component of the propylene-ethylene copolymer is 2.5 to 4.0 dl / g from the viewpoint of the balance between the suppression of low molecular weight components and the processability.

In particular, the ratio of [η] B / [η] A is 0.8 to
1.5 is more preferable from the viewpoint of transparency.

The intrinsic viscosity is measured in tetralin at 135 ° C. using an Ubbelohde viscometer. The intrinsic viscosity ([η] A) of the component A is analyzed by sampling the copolymer after the completion of the polymerization in the first step. Intrinsic viscosity of component B ([η]
B) samples the block copolymer after the completion of the polymerization in the second step and determines the intrinsic viscosity ([η] A) of the block copolymer.
B) is analyzed, and is further obtained from the following formula from the ratio of the A component (PA) and the ratio of the B component (PB). [Η] A × PA / 100 + [η] B × PB / 100 =
[Η] AB [η] B = ([η] AB-[η] A x PA / 100) x
100 / PB

From the viewpoints of transparency and impact resistance at low temperature, the propylene-based block copolymer has a content of ethylene units of component B (EB) and a content of ethylene units of component A (E).
The difference (EB-EA) from A) is preferably in the range of 3 to 15% by weight. It is particularly preferable that EB-EA is 5 to 10% by weight from the viewpoint of a balance between transparency and impact resistance at low temperatures.

The propylene block copolymer used in the present invention is a batch polymerization method in which, for example, a component A is polymerized in the same polymerization tank in the presence of a Ziegler-Natta type catalyst, and then the component B is polymerized. Alternatively, it can be produced by a continuous polymerization method for continuously polymerizing the component A and the component B using a polymerization tank comprising at least two tanks.

Specifically, for example, in the presence of (a) an organosilicon compound having a Si—O bond, a compound of the general formula Ti (OR
¹ ) A titanium compound and / or an ether compound represented by _n X _4-n (R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen atom, and n is a number satisfying 0 <n ≦ 4). A trivalent titanium compound-containing solid catalyst component obtained by treating a solid product obtained by reducing with an organomagnesium compound with a mixture of an ester compound and an ether compound with titanium tetrachloride; (b) an organoaluminum compound (c) Si-oR ² bonds (R ² is a hydrocarbon group having 1 to 20 carbon atoms.) the catalyst system consisting of a silicon compound having, or (a) the general formula Ti (oR ¹⁾ _n X _{4- n} (R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen atom, n is a number satisfying 0 <n ≦ 4), and a titanium compound represented by the general formula AlR ² _m Y _3-m (R ² is a hydrocarbon group having 1 to 20 carbon atoms, Y is And a solid product containing a hydrocarbyloxy group insoluble in a hydrocarbon solvent obtained by reduction with an organoaluminum compound represented by the following formula: After the polymerization treatment, a hydrocarbyloxy group-containing solid catalyst component obtained by treating in a slurry state at a temperature of 80 to 100 ° C. in the presence of an ether compound and titanium tetrachloride in a hydrocarbon solvent, (b) an organoaluminum compound In the presence of a Ziegler-Natta type catalyst comprising titanium, magnesium and halogen as essential components, such as a catalyst system comprising a catalyst system, the molar ratio of Al atom in component (b) / Ti atom in component (a) is 1 to 2000, preferably 5 to 1500,
The molar ratio of Al atoms in component (c) / component (b) is set to 0.0
The polymerization temperature is 20 to 150 ° C, preferably 50 to 95 ° C.
° C., the polymerization pressure is atmospheric pressure ~40kg / cm ² G, preferably under conditions of 2~40kg / cm ² G, and supplies the hydrogen to propylene and ethylene and the molecular weight regulator in the first step propylene - ethylene copolymer After the production of the polymer portion (component A), propylene, ethylene and hydrogen are supplied in the second step to produce the propylene-ethylene copolymer portion (component B).

The propylene-based block copolymer used in the present invention is improved in transparency by further containing a nucleating agent, and the crystallization speed is improved, so that the molding cycle can be shortened. The nucleating agent is not particularly limited, and examples thereof include sorbitol-based nucleating agents, organic phosphate-based nucleating agents, polyvinylcycloalkanes, and high-molecular-weight nucleating agents such as low-pressure high-density polyethylene. Can be Sorbitol-based nucleating agent contributes to transparency and molding cycle, organic phosphate-based nucleating agent, low-pressure method high-density polyethylene has less odor, and polymer-based nucleating agent such as polyvinylcycloalkane is about 10 ppm. Also improves the transparency.

The propylene block copolymer used in the present invention can change the fluidity represented by a melt flow rate by a known method in the presence or absence of an organic peroxide. . Further, the propylene-based block copolymer may contain an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, an antifogging agent, a colorant, and the like, as necessary.

The multilayer blow-molded container of the present invention can have at least one layer composed of only the above-mentioned propylene-based block copolymer, but can also contain other resins within a range not to hinder the present invention. .

The multilayer hollow molded container of the present invention preferably has an outermost layer made of an olefin resin. The olefin resin is a polymer containing olefin as a main component,
For example, ethylene homopolymer, ethylene-α-olefin copolymer (α-olefin is at least one of α-olefins having 3 to 18 carbon atoms), propylene homopolymer, and propylene-α-olefin random copolymer Polymer (α-olefin is an α-olefin having 2, 4 to 18 carbon atoms)
-At least one of olefins), propylene-based block copolymer (excluding the above-mentioned propylene-based block copolymer), butene-1 homopolymer, 4-methyl-
1-pentene homopolymer and the like. Among them, ethylene homopolymer, ethylene-α-olefin copolymer, propylene homopolymer, propylene-α-olefin random copolymer, and propylene block copolymer are preferable. These can be used alone or in combination of two or more. For example, a propylene-ethylene random copolymer, a propylene-ethylene-butene-1 copolymer, an ethylene-butene-1 copolymer and the like can be mentioned. The olefin resin has a haze of 30% or less, preferably 2% when formed into a 1 mm-thick press sheet.
What is 5% or less is more preferable in terms of transparency and gloss of the container. Haze can be measured according to JIS K7105.

The olefin resin may further contain a nucleating agent. Examples of the nucleating agent include those used for the propylene-based block copolymer.

The multilayer hollow molded container of the present invention comprises two or more layers, for example, a two-layer hollow molded container in which the outermost layer is made of the olefin resin and the inner layer is made of the propylene block copolymer. No. Examples of the three-layer hollow molded container include a multilayer hollow molded container in which the outermost layer and the innermost layer are made of the olefin-based resin, and the intermediate layer is made of the propylene-based block copolymer.

The multilayer blow-molded container of the present invention may have a layer using a recycled material obtained by pulverizing burrs generated during blow molding. The layer containing the recycled material may be a single recycled material or a mixture with a resin of another layer.

The multilayer blow-molded container of the present invention can also have a surface modification such as, for example, silk-screen printing, offset printing, shrink label, stretch label, and in-mold label. The multilayer hollow molded container of the present invention preferably has an in-mold label.

The method for producing the multilayer hollow molded container of the present invention is not particularly limited, and examples thereof include a known direct blow molding method and a biaxial stretch blow molding method. The multilayer hollow molding container of the present invention is, for example, a multilayer molten parison extruded from a plurality of extruders is set in a container-shaped mold of a hollow molding machine, and after being inflated to the mold inner wall by blowing compressed gas. , A container taken out after cooling. Also, for example, after preheating an injection-molded multilayer bottomed parison, it is set in a container-shaped mold, expanded vertically to the inner wall of the mold by longitudinal stretching with a rod and blowing compressed gas, and then taken out after cooling. Container.

[0039]

Next, the present invention will be described based on examples, but the present invention is not limited to these examples.
First, methods for measuring physical properties in the following Reference Examples and Reference Comparative Examples will be described. (1) 20 ° C. xylene-soluble part (CXS part) After completely melting 5 g of a sample in 500 ml of boiling xylene,
The temperature was lowered to ° C. and left for 4 hours or more. Thereafter, the precipitate and the solution were separated by filtration, and the amount of resin in the solution was quantified. This value was expressed as a percentage (% by weight). (2) Maximum melting peak temperature (Tm) of the portion excluding the CXS part (CXIS part) After completely melting 5 g of the sample in 500 ml of boiling xylene,
The temperature was lowered to ° C. and left for 4 hours or more. Thereafter, the precipitate and the solution were separated by filtration, and the precipitate was dried and dried at 70 ° C. under reduced pressure to obtain a CXIS part. 10 mg of this CSIS part was previously melted at 220 ° C. for 5 minutes in a nitrogen atmosphere using a differential scanning calorimeter (DSC7, manufactured by PerkinElmer).
The temperature was lowered to 40 ° C. at a rate of 5 ° C./min. Then 5
The temperature was raised at a rate of ° C./min, and the maximum peak temperature of the obtained melting curve was determined.

(3) Ratio of Component A and Component B (% by Weight) The ratio of component A (PA) and the component B (PB) were determined from the material balance during polymerization of component A and component B. (4) Intrinsic viscosity ([η]) Measurement was performed in tetralin at 135 ° C. using an Ubbelohde viscometer. Intrinsic viscosities of components A and B ([η] A, [η] B) Intrinsic viscosities [η] A measured after completion of polymerization of component A in the first step, and intrinsic viscosities measured after completion of polymerization in the second step [Η] AB, ratio of component A (PA), ratio of component B (PB), intrinsic viscosity of component B [η] B
Was decided. [Η] B = ([η] AB− [η] A × PA / 100) ×
100 / PB

(5) Ethylene Unit Content Polymer Handbook (published by Kinokuniya Bookstore in 1995)
¹³ C-N by the method described on page 616 of
The measurement was performed by the MR method. Content of ethylene unit of component A and component B (EA, EA) The content of ethylene unit (EA) measured after completion of polymerization of component A in the first step, and the content of ethylene unit measured after completion of polymerization of second step From the content (EAB), the ratio of the component A (PA), and the ratio of the component B (PB), the content (EB) of the ethylene unit of the component B was determined by the following equation. EB = (EAB-EA × PA / 100) × 100 / PB (6) Melt flow rate (MFR) Measured according to JIS K7210 under the condition -14.

(7) Transparency (Haze) The transparency of a hollow molded container was measured in accordance with JIS K7105 by cutting out a body having a height of 80 mm as a test piece. The transparency of the press sheet was measured according to JIS K7105 by preparing a 1 mm press sheet. The smaller this value is, the more excellent the transparency is. (8) Gloss (gloss) The body of the hollow molded container having a height of 80 mm was cut out as a test piece and measured in accordance with JIS K7105. The larger the value, the better the gloss. (9) Flexural modulus Measured according to JIS K7106. The smaller the value, the more excellent the flexibility.

(10) Izod Impact Strength A test piece was allowed to stand in a thermostat at a temperature of 0 ° C. for 24 hours or more according to JIS K7110, and then measured. The larger this value is, the more excellent the impact resistance is. (11) Compressive strength (Reference Example 1, Reference Comparative Example 1) After the hollow molded container was allowed to stand in a constant temperature room at a temperature of 23 ° C for 24 hours or more, a bending tensile tester STM- manufactured by Toyo Baldwin Co.
Using F-5000BP, a compression test was performed at a compression speed of 50 mm / min with the hollow molded container placed sideways,
The compression load at a strain of 20 mm was measured. The smaller the value, the more excellent the flexibility. (12) Compressive strength (Reference example 2) After leaving the hollow molded container in a constant temperature room at a temperature of 23 ° C for 24 hours or more, a bending tensile tester STM- manufactured by Toyo Baldwin Co., Ltd.
Using F-5000BP, the compression test was performed at a compression speed of 50 mm / min in a state where the hollow molded container was placed vertically,
The compression load at a strain of 20 mm was measured. The smaller the value, the more excellent the flexibility.

(13) Drop test (Reference Example 1, Reference Comparative Example 1) A hollow molded container was filled with 500 g of water, left standing in a low-temperature constant temperature bath at 5 ° C for 24 hours or more, and then concreted from a height of 1.5 m. After free fall repeatedly 10 times with the bottom of the container on the floor,
The container was observed for damage and cracks. The residual ratio was measured from the number of undestructed 10 test containers. (14) Drop test (Reference example 2) 1 kg of water is filled in a hollow molded container, and the container is allowed to stand in a low-temperature constant temperature bath at 5 ° C for 24 hours or more. Then, the container bottom is placed on a concrete floor from a height of 1.5 m. After repeatedly free falling 10 times, the container was observed for damage and cracks. The residual ratio was measured from the number of undestructed 10 test containers.

REFERENCE EXAMPLE 1 [Synthesis of solid catalyst] After replacing a 200 LSUS reactor equipped with a stirrer with nitrogen, 80 L of hexane, 6.55 mol of tetrabutoxytitanium, 2.8 of diisobutyl phthalate was used.
And 98.9 mol of tetraethoxysilane were added to obtain a uniform solution. Next, a diisobutyl ether solution of butylmagnesium chloride having a concentration of 2.1 mol / L was prepared.
1 L was gradually dropped over 5 hours while maintaining the temperature in the reaction vessel at 5 ° C. After completion of the dropwise addition, the mixture was further stirred at room temperature for 1 hour, then subjected to solid-liquid separation at 20 ° C., and washed three times with 70 L of toluene. Then, the slurry concentration was 0.2 kg /
After adding toluene so as to obtain L, 47.6 mol of diisobutyl phthalate was added, and the reaction was carried out at 95 ° C. for 30 minutes. After the reaction, the mixture was separated into solid and liquid, and washed twice with toluene. Next, 3.13 mol of diisobutyl phthalate, 8.9 mol of butyl ether and 274 mol of titanium tetrachloride were added, and the mixture was reacted at 105 ° C. for 3 hours. After the completion of the reaction, the mixture was subjected to solid-liquid separation at the same temperature, and then washed twice with 90 L of toluene at the same temperature. Next, the slurry concentration was set to 0.4 kg /
After adjusting to L, 8.9 mol of butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was reacted at 105 ° C. for 1 hour. After the completion of the reaction, solid-liquid separation was performed at the same temperature, and the solid was washed three times with 90 L of toluene at the same temperature.
After washing three times with 0 L, the solid catalyst component was dried under reduced pressure.
4 kg were obtained. The solid catalyst component contains 1.8% by weight of titanium atom, 20.1% by weight of magnesium atom, 8.4% by weight of phthalic ester, 0.3% by weight of ethoxy group and 0.2% by weight of butoxy group, and has no fine powder. It had good particle properties.

[Preparation of polymer] <Pre-activation of solid catalyst component>
30. 1.5 L of n-hexane, triethylaluminum sufficiently dehydrated and degassed in an autoclave with a stirrer
5 mmol, 37.5 mmol of t-butyl-n-propyldimethoxysilane and 15 g of the above-mentioned solid catalyst component were added, and propylene 15
g was continuously supplied over about 30 minutes to perform pre-activation, and then the obtained solid catalyst slurry was transferred to a 150 L SUS autoclave equipped with a stirrer, and 100 L of liquid butane was added and stored. [Polymerization] Two tanks of a 1 m ³ SUS fluidized bed reactor with a stirrer were connected, and the first tank was used for copolymerization of propylene and ethylene in the first stage (component A), and the second tank was used for the second stage. Copolymerization of propylene and ethylene in part (component B) was continuously carried out. (1) First tank (component A) In a fluidized-bed reactor with a stirrer having an internal volume of 1 m ³ , a polymerization temperature of 70 ° C., a polymerization pressure of 18 kg / cm ² G, a hydrogen concentration of 0.2% by volume in a gas phase, Gas phase part ethylene concentration 2.4vo
While supplying propylene, ethylene and hydrogen so as to maintain 1%, triethylaluminum 75 mmol / h, t-butyl-n-propyldimethoxysilane 7.
5 mmol / h and preactivated solid catalyst component
29 g / h was continuously supplied, and propylene and ethylene were copolymerized at a polymer bed holding amount of 45 kg in the fluidized bed to obtain a polymer of 9.6 kg / h. The obtained polymer was continuously transferred to the second tank without deactivation. Also, as a result of sampling and analyzing a part of the polymer,
The content of ethylene unit is 3.7% by weight, and tetralin 13
The intrinsic viscosity ([η]) at 5 ° C. was 2.80 dl / g. (2) Second tank (component B) In a fluidized bed reactor with a stirrer having an internal volume of 1 m ³ , a polymerization temperature of 80 ° C., a polymerization pressure of 12 kg / cm ² G, a hydrogen concentration of 0.2% by volume in a gas phase, Gas phase part ethylene concentration 9.0 vo
while supplying propylene, ethylene and hydrogen so as to maintain 1%, the polymer hold amount of the fluidized bed was set to 80 k.
g, by continuously continuing the copolymerization of ethylene and propylene with the catalyst-containing polymer transferred from the first tank, a white polymer of 18.1 kg / h with good fluidity was obtained. The content of ethylene units in the obtained polymer was 8.8% by weight, and the intrinsic viscosity ([η]) at 135 ° C. of tetralin was 2.89 dl / g. From the above results, the polymerization amount ratio of the first tank and the second tank was 53/47, and the content of the ethylene unit in the component B obtained from the analysis values of the component A and the final polymer was 14.6% by weight. %, Intrinsic viscosity at 135 ° C. ([η]) was 3.0 dl / g. Therefore, [η] B / [η] A was 1.1. The obtained polymer was decomposed by heating in the presence of peroxide, and the MFR was adjusted to 1.1 g / 10 minutes to obtain a propylene block copolymer. The 20 ° C. xylene-soluble portion (CXS portion) of the obtained propylene copolymer was 22% by weight, and the D (CXIS portion) excluding the CXS portion was D.
The highest melting peak temperature (Tm) in SC was 131 ° C.

[Production of hollow molded container] The obtained propylene block copolymer was supplied to a hollow molding machine (NB3B type; screw diameter 50 mm, L / D = 20) manufactured by Japan Steel Works, Ltd. Temperature 210 ° C, air blowing pressure 6k
Air was blown in for 10 seconds at g / cm ² , and the parison low side was pinched off by a mold and melt-bonded, the side thickness was about 0.4 mm, the weight was 16 g, and the capacity was 500 ml.
Was manufactured. Table 1 shows the performance evaluation results of the obtained single-layer hollow molded container and the evaluation results of the heat compression molded sheet.

Example 1 95% by weight of a propylene-ethylene random copolymer (content of ethylene unit: 2.8% by weight) and 5% by weight of ultra-low density polyethylene (MFR (190 ° C.): 5 g / 10 minutes) To prepare a resin mixture containing
0.12% by weight of a crystal nucleating agent (Adeka Stab NA21 manufactured by Asahi Denka) with respect to 00% by weight, melt kneading, and MF
A propylene-based resin composition having an R of 2.8 g / 10 minutes was obtained. The haze of the 1 mm-thick press sheet of the resin composition was 25%. The propylene block copolymer described in Reference Example 1 is supplied as an inner layer and the propylene-based resin composition is supplied to a multi-layer hollow molding machine to form a multi-layer hollow molding container so as to form an outermost layer.

Reference Comparative Example 1 The procedure of Reference Example 1 was repeated except that the propylene block copolymer in Reference Example 1 was replaced with a propylene homopolymer having an intrinsic viscosity of 2.57 dl / g and an MFR of 1.1 g / 10 minutes. The same operation was performed to produce a single-layer hollow molded container. Table 1 shows the evaluation results.

Example 2 100% by weight of a propylene-ethylene-butene-1 copolymer (ethylene unit content = 1.1% by weight, butene-1 unit content = 4.2% by weight) and crystal nucleation 0.15% by weight of an agent (Shin Nippon Rika's Gelol MD) was melt-kneaded in the presence of peroxide to give an MFR of 22 g / 10 g.
Propylene-based resin composition was obtained. The 1% -thick press sheet of the resin composition had a haze of 14%. The propylene block copolymer described in Reference Example 1 is supplied as an inner layer and the propylene-based resin composition is supplied to a multi-layer hollow molding machine to form a multi-layer hollow molding container so as to form an outermost layer.

Reference Example 2 The same polymer as obtained in Reference Example 1 before the thermal decomposition was thermally decomposed in the presence of a peroxide so that the MFR became 8.6 g / 10 minutes, and the propylene block copolymer was obtained. Obtained. This polymer was injected into an injection molding machine (J1) manufactured by Japan Steel Works, Ltd.
00E type) and injection molding at a cylinder temperature of 190 ° C.
A preform (diameter 29 mm, length 123 mm, thickness 3.9 mm, weight 29 g) was obtained. This preform
Frontier's stretch blow molding machine (EFB2000)
After heating with an infrared heater and cooling with air, heating and adjusting the preform temperature to 120 to 130 ° C., longitudinal stretching with a stretch rod and blowing with compressed air are performed to obtain a capacity of 1 L, high 275
mm, and a width of 72 mm (longitudinal stretching ratio 2.4 times, circumferential direction stretching ratio 3.0 times, area stretching ratio 7.2 times) were produced. Table 2 shows the evaluation results.

Example 3 A propylene block copolymer described in Reference Example 2 and a propylene-ethylene random copolymer (ethylene unit content = 4.8% by weight, MFR = 24 g / 10 minutes, intrinsic viscosity = 1. 38 dl / g, haze of a 1 mm thick pressed sheet = 15%) and 2 or more injection cylinders
Injection molding is performed with a color injection molding machine to obtain a multilayer preform having two or more layers with the propylene-ethylene random copolymer as the outermost layer. The preform is supplied to a stretch blow molding machine and stretch blow molded to obtain a multilayer hollow molded container.

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Table 1-----------------------. −−−−−−−−−−−−−−−−−−−−−− Thickness mm 0.41 0.40 0.39 Haze% 31 39 54 Gross% 32 18 15 Flexural modulus kg / cm ² 5000 8300 12300 Compressive load kg / Cm ² 0.57 0.82 1.26 Izod impact strength kgcm / cm ² 38.6 21.0 1.6 Drop test survival rate% 100 90 0 −−−−−−−−−−−−−−−−−−−−−−−−−− −−−

[0054]

As described in detail above, according to the present invention,
A multilayer hollow molded container excellent in transparency, flexibility and low-temperature impact resistance can be provided. Also, the multilayer hollow molded container of the present invention is a container for daily necessities liquids such as hair washes, hairdressing agents, cosmetics, detergents, bactericides; liquid containers for soft drinks, mineral water, seasonings, etc .; It can be applied to a wide range of uses as containers and industrial liquid containers. Further, the production method of the present invention can efficiently produce a multilayer hollow molded container having the above-mentioned excellent properties.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Eisuke Shiratani 5-1, Anesaki Beach, Ichihara-shi, Chiba F-term (reference) in Sumitomo Chemical Co., Ltd. 4F208 AA11C AA11F AB08 AG03 AG07 AH55 LA01 LA04 LB19 LB22

Claims (7)

[Claims] 1. A multilayer blow-molded container comprising two or more layers, comprising at least 5% by weight of a xylene-soluble part (CXS part) at 20 ° C. and excluding the CXS part (CXIS part). At least one layer made of a propylene-based block copolymer having a peak temperature (Tm) of 130 to 155 ° C.
A multilayer blow-molded container characterized by having a layer. 2. A propylene-based block copolymer comprising a propylene-ethylene copolymer portion (A component) having a content of a repeating unit derived from ethylene in the first step of 1.5 to 6.0% by weight. Propylene-ethylene copolymer having a total polymerization amount of 40 to 85% by weight based on the total amount of component A and the following component B, and then having a content of a repeating unit derived from ethylene of 7 to 17% by weight in the second step. Part (B component) is 15 to 60% by weight of the total polymerization amount (total of A component and B component)
It is a block copolymer obtained and produced, wherein the intrinsic viscosity of component B ([η] B) is 2 to 5 dl / g, the intrinsic viscosity of component B ([η] B) and the intrinsic viscosity of component A ( [Η] A)
The multilayer hollow molded container according to claim 1, wherein the ratio is [propylene] block copolymer having a ratio of [[η] B / [η] A) of 0.5 to 1.8. 3. The multilayer hollow molded container according to claim 1, wherein the propylene-based block copolymer further contains a nucleating agent. 4. The multi-layer hollow molding container according to claim 1, wherein the outermost layer of the multi-layer hollow molding container is made of an olefin resin, and when the olefin resin is formed into a press sheet having a thickness of 1 mm, the haze is 30% or less. container. 5. The multilayer blow-molded container according to claim 4, wherein the olefin resin further contains a nucleating agent. 6. The multilayer hollow molded container according to claim 1, wherein the multilayer hollow molded container has an in-mold label. 7. A method for producing a multilayer hollow molded container according to claim 1, wherein the container is produced by a direct blow molding method or a biaxial stretch blow molding method.