JPH07164548A - Manufacture of sheet - Google Patents

Abstract

PURPOSE:To obtain a sheet having excellent transparency, heat resistance, and softness by cooling a melting pipe sheet from both faces by using an outside cooling liquid tank and a cooling mandrel so as to make a crystal structure of a propylene copolymer in a smectic crystal. CONSTITUTION:A crystalline random copolymer 45-95wt.% of a propylene having a Q value of 4.5 or less and one kind or more of alpha-olefin and a composition consisting of a hydrogenated waterial 5-55wt.% of 1-butene crystalline homopolymer and/or a styrene block copolymer are melted and extruded downward from an annular die 1 so as to make a pipe sheet 2, which is expanded by sending a pressure air to the inside. During a period that the sheet moves slidably in contact with the outside surface of a cooling mandrel 5 of inside cooling type which is arranged in an outside cooling liquid tank 8 containing an outside cooling liquid penetrating its tank bottom, and whose face contacting with the film forms a cylindrical shape, the outside of the sheet 2 is cooled by the cooling liquid and the inside of the sheet 2 is cooled by the cooling mandrel 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sheet having excellent flexibility, transparency and heat resistance.

[0002]

2. Description of the Related Art Polypropylene resin is inexpensive and has chemical resistance,
It has excellent rigidity and heat resistance, but lacks flexibility. In addition, injection stretch blow molded products, molded products with a high draw ratio during molding such as biaxially stretched polypropylene film, and molded products obtained by further stretching the primary molded product have high transparency. The transparency of a sheet obtained by molding or cast molding, a molded article having a low draw ratio during molding such as a blow molding container, etc. is not always sufficient. In order to improve the transparency of the polypropylene resin, a method of adding dibenzylidene sorbitol, alkyl benzylidene sorbitol, etc. has been proposed, but the obtained molded product generates odor and is used for food packaging and pharmaceutical packaging applications. Can not. Further, in order to impart flexibility to the polypropylene resin, a method of blending a soft resin having good compatibility with the polypropylene resin has been performed, but in order to exert a sufficient effect, the blending amount of the soft resin increases, As a result, there is a problem that the heat resistance of the blended resin is lowered. In applications such as medical bags such as infusion bags and blood bags that require heat resistance, flexibility and high transparency, retort bags, etc., polypropylene that maintains the heat resistance of polypropylene resin and imparts flexibility and transparency Sheets were wanted.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a sheet having excellent transparency, heat resistance and flexibility.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that propylene random copolymer (A) contains (1) 1-butene crystalline homopolymer and / or Alternatively, (2) a resin composition prepared by blending a hydrogenated product (B) of a styrene-based block copolymer in a specific ratio is used as a molten tubular sheet by an inflation molding machine, and the molten tubular sheet is provided with an external cooling liquid tank and a cooling mandrel. The inventors have found that the above problems can be solved by cooling from both sides using a propylene copolymer to make the crystal structure of the propylene copolymer in the composition a smectic crystal, and completed the present invention.

That is, the present invention provides (A) 45 to 95% by weight of a crystalline random copolymer of propylene having a Q value of 4.5 or less and one or more α-olefins, and (B) (1) 1- A tubular sheet obtained by melting a composition comprising a crystalline homopolymer of butene and / or (2) a hydrogenated product of a styrenic block copolymer in an amount of 5 to 55% by weight and extruding the composition below an annular die by melting the composition. After the compressed air is sent to the inside to expand it, the internal liquid-cooled type is placed through the bottom of the external cooling liquid tank containing the external cooling liquid and the contact surface with the film is cylindrical. The outside of the sheet is cooled by the cooling liquid while the inside of the sheet is cooled by the cooling mandrel while sliding in contact with the outside surface of the cooling mandrel, and then the cooled sheet is led out to the lower outside of the external cooling liquid tank. Release from external cooling liquid pressure Propylene copolymer in the composition, characterized in that folding in a state process for producing a sheet having a smectic crystalline structure.

The present invention will be described in detail below.

The propylene copolymer used as the component (A) of the resin composition in the production method of the present invention has a Q value of 4.5 or less, preferably 3.0 or less,
It is a crystalline random copolymer of propylene and a small amount of one or more other α-olefins. The above Q value is (weight average molecular weight) / (number average molecular weight) and represents a molecular weight distribution. When the Q value exceeds 4.5, the crystallization rate of the polypropylene resin increases, and as a result, the flexibility of the obtained sheet decreases, which is not preferable. Further, as the α-olefin which is a copolymerization comonomer, ethylene, 1-butene, 4-
Methyl-1-pentene, 3-methyl-1-butene, 1-
Examples include hexene, 1-octene, 1-nonene, 1-decene and the like. Specific examples of the propylene / α-olefin copolymer include a propylene / 1-butene copolymer containing 0.5 to 20 mol% of 1-butene and 0.5 to 20 mol% of ethylene. And a propylene / ethylene / 1-butene copolymer containing 0.5 to 20 mol% of ethylene and 0.5 to 20 mol% of 1-butene.
The method for measuring the molecular weight in the present invention is shown below.

(Measurement Method of Molecular Weight) Using a gel permeation chromatograph (ALC / GPC-M150C, manufactured by Japan Millipore Limited), a molecular weight distribution curve was obtained under the following conditions and a universal calibration using polystyrene as a standard. The weight average molecular weight and the number average molecular weight were calculated by the Cation method.

Column: GMH-HT (manufactured by Tosoh Corporation) Solvent: o-dichlorobenzene Measurement temperature: 140 ° C. Flow rate: 1 ml / min Melt flow rate of the above propylene copolymer (hereinafter,
It may be abbreviated as "MFR". JIS K6758,2
30 ° C., load 2.16 kg) is not particularly limited, but is preferably 0.2 to 50 g / 10 minutes, 0.4 to 3
0 g / 10 minutes is more preferable, and by setting it in this range, the mechanical strength such as the molding processability, the tensile strength, the tear strength, and the impact resistance of the sheet is further improved.

The method for obtaining the above-mentioned propylene copolymer having a Q value of 4.5 or less is not particularly limited, and a conventionally known method such as a solution method, a slurry method or a gas phase method of propylene and α-olefin is used. Can be obtained by polymerizing
From the viewpoint of production efficiency, it is preferable to obtain by a method of cracking the propylene copolymer obtained by the above-mentioned conventionally known method. When a propylene copolymer is obtained by this method, the Q of the propylene copolymer before cracking is
The value varies depending on the cracking conditions, the type and amount of the organic peroxide used during cracking, etc., but is generally preferably 10 or less. As the cracking method, generally used is a method in which an appropriate amount of organic peroxide is added to a propylene copolymer and melt kneading is performed using a kneader, an extruder, a Banbury mixer or the like. The organic peroxide used during cracking is one or two of hydrogen peroxide.
A compound in which hydrogen atoms are replaced by organic radicals
Specific examples thereof include t-butyl hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, and 2,5-dimethyl-. 2,5 di (t-butylperoxy) hexane,
2,5 dimethyl-2,5 di (t-butylperoxy) hexyne-3,1,3-bis (t-butylperoxyisopropyl) benzene, 1,1-bis (t-butylperoxy) 3,3,5- Examples include trimethylcyclohexane, benzoyl peroxide, p-chlorobenzoyl peroxide, t-butylperoxybenzoate, t-butylperoxyisopropylbenzoate, methylethylketone peroxide, methylisobutylketone peroxide, t-butylperacetate, t-butylperbenzoate. Of these, 2,5 dimethyl-2,5 di (t-butylperoxy) hexane,
2,5 Dimethyl-2,5 di (t-butylperoxy) hexyne-3, etc., which has a decomposition temperature of 110 ° C or higher in order to obtain a half-life of 10 hours for safety, and has no cyclic hydrocarbon for hygiene. A chain structure is preferably used. The addition amount of these organic peroxides, the kneading time and the kneading temperature are
It may be appropriately selected depending on the type of kneading machine, the decomposition temperature of the organic peroxide, and the like. For example, an extruder is used as the kneading machine,
When an organic peroxide having a decomposition temperature of 120 to 180 ° C. for obtaining a half-life of 10 hours is used, the addition amount of the organic peroxide is 0.001 to 0 with respect to 100 parts by weight of the propylene copolymer. 0.5 parts by weight is preferable, and the kneading resin temperature is preferably 180 to 260 ° C.

The crystalline homopolymer of 1-butene (1) used as one of the components (B) of the resin composition in the production method of the present invention is used for the purpose of improving the flexibility of the propylene copolymer. MFR (JIS K
7210, 190 ° C., load 2160 g) is not particularly limited, but is preferably 0.1 to 100 g / 10 minutes, more preferably 1 to 50 g / 10 minutes. By setting the MFR within this range, the compatibility with the (A) polypropylene copolymer is improved, and blocking of the resin composition is prevented.

As the hydrogenated product (2) of the styrene block copolymer used as one of the components (B) of the resin composition in the production method of the present invention, a hydrogenated styrene / butadiene block copolymer, water Examples thereof include added styrene / isoprene block copolymers. The amount of styrene block in these block copolymers is preferably 8 to 60% by weight, more preferably 10 to 40% by weight. The hydrogenation degree of the double bond in the olefin block such as butadiene and isoprene is preferably 80% or more, more preferably 95% or more. The hydrogenated products of these styrene block copolymers can be produced, for example, by the method described in JP-A-3-72512, and are commercially available (for example, as a commercial product, Kraton (trademark) , Shell Japan Co., Ltd., Septon (trade name, manufactured by Kuraray Co., Ltd.), DYNARON (trade name, manufactured by Japan Synthetic Rubber Co., Ltd., etc.).

The ratio of each of the components (A) and (B) of the resin composition used in the present invention is 45 for the component (A).
-95% by weight, preferably 60-85% by weight, and the component (B) is 5-55% by weight, preferably 15-40% by weight. When the content of the component (A) is less than 45% by weight, moldability is poor, and when it exceeds 95% by weight, flexibility is poor, which is not preferable.

The method for preparing the resin composition comprising the above-mentioned components (A) and (B) used in the present invention is not particularly limited, and each component may be a V blender, a Henschel mixer, a ribbon blender, a tumbler blender, or the like. A known method such as a method of mechanically mixing using, an extruder after mixing, a Banbury mixer, a kneader, a method of melt-kneading and pelletizing using a hot roll or the like is adopted, but each component in the resin composition From the viewpoints of dispersibility and production efficiency, the method of melt kneading using a single-screw or twin-screw extruder is particularly preferable.

In the above-mentioned resin composition used in the present invention, antioxidants, antiblocking agents, lubricants, plasticizers, light stabilizers, ultraviolet absorbers, and additives may be added, if necessary, within a range that does not impair the effects of the present invention. Additives generally added to thermoplastics such as nucleating agents, clarifying agents, antistatic agents, flame retardants, fillers and surfactants may be used. Further, for the purpose of further improving the flexibility and impact resistance of the sheet obtained in the present invention, an ethylene / propylene copolymer rubber containing 50 to 85 mol% of ethylene in the above resin composition, an ethylene / 1-butene copolymer. Rubber, propylene / 1-butene copolymer rubber, ethylene / butadiene copolymer rubber, etc. may be blended.

In the method for producing a sheet of the present invention, a tubular sheet obtained by melting the resin composition by an extruder and extruding the resin composition downward from an annular die is fed with compressed air to expand the tubular sheet, and then an external cooling liquid is used. The outside of the sheet is placed inside the external cooling liquid tank containing the sheet while penetrating through the bottom of the sheet, and the contact surface with the sheet is in contact with and slides on the outer surface of the internal liquid cooling type cooling mandrel having a cylindrical shape. Is cooled by the cooling liquid and the inside of the sheet is cooled by a cooling mandrel, and then the cooled sheet is led out to the lower outside of the external cooling liquid tank and folded in a state of being released from the external cooling liquid pressure. To be

A typical example of an apparatus for carrying out the method of the present invention will be described below with reference to the drawings. In FIG. 1, the molten resin tubular sheet 2 that has passed through the annular slit 1 of the die
Is equal to the outer diameter of the cooling mandrel 5 by the compressed air fed from the compressed air feed pipe 4 while precooling by the cold air blown out from the air ring 3 if necessary.
It is expanded to a slightly larger diameter. An overflow pipe 1 that is supplied from an external cooling liquid inlet pipe 9 and can move up and down
By overflowing from 0, the tubular sheet is guided into the external cooling liquid in the external cooling liquid tank 8 kept at a predetermined liquid level, and the outside of the tubular sheet is directly cooled, and at the same time, the cooling liquid inlet pipe 6 The inside of the tubular sheet is also cooled by sliding on the surface of the cooling mandrel 5 which has a hollow inside and is cooled by the cooling liquid which is further fed and discharged from the cooling liquid discharge pipe 7. A hole having a diameter slightly larger than the diameter of the cooling mandrel is formed at the center of the bottom of the external cooling liquid tank 8, and the gap between the periphery of this hole and the tubular sheet on the cooling mandrel is a soft elastic material 12 such as a blanket or sponge. The tubular sheet has a structure that allows it to slide smoothly between the elastic surface and the cooling mandrel surface, so that the sheet surface is not scratched and external cooling liquid does not leak from the bottom of the liquid tank. can do. Next, the tubular sheet leaving the cooling mandrel is guided further downward, and is gradually folded by the stabilizer 13 so as not to be wrinkled, and the nip roll (pinch roll) 1
It is taken up after 4 steps.

In the production method of the present invention, the tubular sheet needs to be cooled at the same time by the cooling mandrel and the external cooling liquid, and the cooling mandrel and the external cooling liquid are used for sequential cooling, the cooling mandrel or the external cooling liquid. In the method of cooling using either one of the above, the crystal structure of the propylene copolymer in the composition does not become a smectic crystal and the transparency and flexibility of the sheet are poor. The external cooling liquid and the cooling liquid in the mandrel may be of the same type or different types, but it is necessary that they do not dissolve or corrode the material of the sheet or mandrel. It is most convenient to use water as the internal cooling liquid. The temperature of the external cooling liquid varies depending on the thickness of the sheet, the speed of drawing the sheet, etc.
C. or less is preferable, and 30.degree. C. or less is more preferable. By setting the cooling liquid temperature to 60 ° C. or lower, the transparency and flexibility of the sheet obtained are further improved. The temperature of the cooling liquid inside the mandrel varies depending on the structure of the mandrel, the sheet take-up speed, etc.
The surface temperature of the mandrel is preferably 60 ° C. or less, and more preferably 30 ° C. or less. When the surface temperature is 60 ° C. or lower, the transparency and flexibility of the sheet are improved.

When the tubular sheet is cooled to the position of the stabilizer 13 or the nip roll 14 below the cooling mandrel by the external cooling liquid, the tubular sheet is crushed and wrinkled by the liquid pressure, which is not preferable. When the cooling liquid is sprinkled, the liquid adheres to the inner surface of the tubular sheet after film formation, and the contents become wet during packaging and heat sealing becomes difficult, which cannot be put to practical use as it is. Further, in order to continuously dry the cooling liquid adhering to the inner surface of the sheet, a special and complicated drying device is required, which complicates the process and increases the manufacturing cost.

The smectic crystal structure obtained by quenching the molten tubular sheet in the present invention is one of the crystal structures of the propylene copolymer, and as shown in FIG. 2, the diffraction angle (2θ) is 10 to 30 °. X-ray diffraction in the range of 1
It refers to a crystal structure in which two broad peaks appear only around 4.6 ° and around 21.2 °. This smectic crystal is described in literature (for example, JOURNAL OF MATERI
ALS SCIENCE 27, 4350-4352, 1
As described in 992), it is known that by heating at a temperature of 60 ° C. or higher, the α-crystal is transformed, and the transformation is an exothermic reaction. When polypropylene sheets having various crystal structures are subjected to a differential scanning calorimeter (hereinafter sometimes abbreviated as “DSC”), generally endothermic peaks and smectic peaks, which are considered to be based on the melting of the microcrystals, sequentially from the low temperature side. An exothermic peak due to the transition from the crystal to the α crystal and an endothermic peak due to the melting of the α crystal appear. The ratio R of smectic crystals in polypropylene crystals having various crystal structures can be obtained by the following formula, where S1 is the exothermic peak area based on the thermal transition of smectic crystals to α crystals. R (%) = 100S ₁ / S ₀ (where S ₀ is the exothermic peak area due to the thermal transition of the sheet having a smectic crystal structure of 100% to α crystal) By the way, from the above smectic crystal to α crystal The exothermic peak due to the transition and the endothermic peak due to the melting of the α-crystal tend to shift to the high temperature side when subjected to a thermal history, and depending on the thermal history conditions, the above-mentioned three peaks appear close to each other. Therefore, in determining the exothermic peak area based on the thermal transition of the smectic crystal to the α crystal by differential scanning calorimetry, it is important to separate each peak. In the present invention, each peak was separated by drawing a baseline by the method as described in Examples below. The ratio R of smectic crystals in the crystal structure of the propylene resin sheet obtained by the production method of the present invention is preferably 5
% Or more, more preferably 10% or more. This ratio R
Is less than 5%, the transparency and flexibility of the sheet obtained by the production method of the present invention are poor.

The thickness of the sheet obtained by the present invention is not particularly limited and may be appropriately selected depending on the application. For example, an infusion bag is usually 200 to 300 μm, and a retort bag is usually 100 to 200 μm. is there.

[0022]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. The performances in Examples and Comparative Examples were measured by the following methods. Moreover,% in the examples and comparative examples is% by weight.

Transparency Haze was measured according to JIS K6758. The smaller the measured value, the better the transparency.

Heat resistance High temperature and high pressure sterilization tester (RCS-40RTGN-FAM,
The temperature of the test piece was 115 ° C using Hisaka Seisakusho Co., Ltd.
The sample is heat treated for 40 minutes, the 1% secant elastic modulus of the test piece is measured, and the ratio to the measured value before the heat treatment, that is,
0 × (measured value after heat treatment) / (measured value before heat treatment)) was calculated. When the calculated value was in the range of 80 to 120%, it was evaluated as excellent in heat resistance.

Flexibility According to JIS K7127, 1% secant elastic modulus was measured. The smaller the measured value, the better the flexibility.

Measurement condition for obtaining DSC chart About 5 m from the sheet obtained by inflation molding
g sample and weigh 2 g at room temperature to 80 ° C / min
Raise the temperature to 30 ° C.

Reference Example 1 Random copolymer of propylene and ethylene (MFR;
1.6 g / 10 minutes, ethylene content; 5.8 mol%) 10
0.017 part of 2,5 dimethyl-2,5 di (t-butylperoxy) hexane as an organic peroxide was added to 0 part, and the mixture was melted and kneaded with a twin screw extruder at a resin temperature of 230 ° C. after mixing with a tumbler blender. After pelletizing, MFR10
A polypropylene cracking product having a g / 10 min and a Q value of 2.9 was obtained.

This cracking product was heated at 230 ° C. from the annular slit 1 of the inflation molding machine shown in FIG.
To form a tubular sheet, which is cooled in a cooling mandrel 5 cooled with cooling water having a temperature of 10 ° C. and an external cooling liquid tank 8 filled with cooling water having a liquid temperature of 10 ° C. 2 through the nip roll 14
The sheet was wound at a speed of 5 m / min to obtain a sheet having a thickness of 300 μm.

The obtained sheet was subjected to X-ray analysis using an X-ray analyzer (JDX-11PA manufactured by JEOL Ltd.), and the crystal structure shown in FIG. 2 was 100% smectic crystal.
A line analysis pattern was obtained. A DSC chart shown in FIG. 3 was obtained using this sheet. Reference Example 2 The cracked product obtained in Reference Example 1 was wound at a resin temperature of 230 ° C. at an extrusion speed of 15 m / min using a normal cast molding machine to obtain a sheet having a thickness of 300 μm. When the obtained sheet was subjected to X-ray analysis in the same manner as in Reference Example 1, the crystal structure was 100% α crystal as shown in FIG. Further, using this sheet, a DSC chart shown in FIG. 5 was obtained.

Reference Examples 3 to 4 Sheets were produced in the same manner as in Reference Example 1 except that the cooling conditions for the sheet during inflation molding in Reference Example 1 were as shown in Table 1. The DSC chart of the obtained sheet was as shown in FIG. In order to separate the three peaks appearing on the DSC chart of FIG. 6, 100% α shown in FIG.
A baseline was drawn with reference to the DSC curve of the crystal. This baseline is indicated by a broken line in FIG. The area of the portion surrounded by the exothermic peak and the baseline was obtained from the DSC chart as S ₁ (exothermic peak area based on thermal transition of smectic crystal to α crystal), and S ₀ (100% of 100% The exothermic peak area due to the thermal transition to α crystal of the film having a smectic crystal structure is calculated to obtain R
(%) = 100 S ₁ / S ₀ was calculated. The results are shown in Table 1.

Examples 1 to 3 and Comparative Example 1 Homopolymer of cracking product and 1-butene obtained in Reference Example 1 (MFR; 45 g / 10 min, trade name: Polybutene M8510, Mitsui Petrochemical Co., Ltd.) Were mixed in a ratio shown in Table 2, mixed in a tumbler blender, melt-kneaded in a single-screw extruder, and pelletized. A sheet was obtained using the obtained pellets under the same conditions as in Reference Example 1.

The results of measuring the physical properties of the obtained sheet are shown in Table 2. The sheet of this example is excellent in transparency, heat resistance and flexibility. 45% polypropylene resin
The resin composition of Comparative Example 1 below had poor moldability and a smooth sheet could not be obtained.

Comparative Example 2 Using the polypropylene cracking product obtained in Reference Example 1 alone, a sheet was prepared under the same conditions as in Reference Example 1, and this sheet was used as a test piece to measure various physical properties. Show. The sheet of this comparative example containing no polybutene-1 was inferior in flexibility.

Comparative Example 3 Random copolymer of propylene and ethylene (MFR;
1.6g / 10min, ethylene content; 5.8mol%, Q
Value; 5.0) and 1-butene homopolymer (MFR; 45
g / 10 minutes, trade name; polybutene M8510, manufactured by Mitsui Petrochemical Industry Co., Ltd. were blended at the ratios shown in Table 2, mixed with a tumbler blender, melt-kneaded with a single-screw extruder, and pelletized. Next, a sheet was prepared under the same conditions as in Reference Example 1, and the results of measuring various physical properties of this sheet as a test piece are shown in Table 2. The sheet of this comparative example using a propylene copolymer having a Q value of more than 4.5 was inferior in flexibility.

Comparative Example 4 Table 2 shows the homopolymer of the cracking product and 1-butene obtained in Reference Example 1 (MFR; 45 g / 10 min, trade name: Polybutene M8510, manufactured by Mitsui Petrochemical Industry Co., Ltd.). The resin composition pellets were prepared in the same proportions as shown in Example 1, and the sheet was prepared under the same conditions as in Reference Example 2. Table 2 shows the results obtained by measuring various physical properties of the obtained sheet as a test piece. The sheet of this comparative example, which did not contain smectic crystals in the crystal structure of the polypropylene resin in the resin composition, was inferior in transparency and flexibility.

Example 4 A sheet was produced using the resin composition pellets obtained in Comparative Example 4 under the same conditions as in Reference Example 3. Table 2 shows the results of evaluating the sheets of this example. The sheet of this example is transparent,
It had excellent heat resistance and flexibility.

Example 5 A sheet was produced using the resin composition pellets obtained in Comparative Example 4 under the same conditions as in Reference Example 4. Table 2 shows the results of evaluating the sheets of this example. The sheet of this example is transparent,
It had excellent heat resistance and flexibility.

Example 6 Cracking product obtained in Reference Example 1 and hydrogenated styrene / butadiene / styrene block copolymer (MFR; 3.5)
g / 10 minutes (ASTM D1238, 230 ° C, load 2
160 g), styrene block content; 10% by weight, trade name; DYNARON 1320P, Nippon Synthetic Rubber Co., Ltd.
Were mixed in a ratio shown in Table 2, mixed in a tumbler blender, melt-kneaded in a single-screw extruder, and pelletized. A sheet was obtained using the obtained pellets under the same conditions as in Reference Example 1.

The results of measuring the physical properties of the obtained sheet are shown in Table 2. The sheet of this example was excellent in transparency, heat resistance and flexibility.

Example 7 Cracking product obtained in Reference Example 1 and hydrogenated styrene / butadiene / styrene block copolymer (MFR; 5.3)
g / 10 minutes (ASTM D1238, 230 ° C, load 2
160 g), styrene block content; 30% by weight, trade name; DYNARON 1320P, Nippon Synthetic Rubber Co., Ltd.
Were mixed in a ratio shown in Table 2, mixed in a tumbler blender, melt-kneaded in a single-screw extruder, and pelletized. A sheet was obtained using the obtained pellets under the same conditions as in Reference Example 1.

The results of measuring the physical properties of the obtained sheet are shown in Table 2. The sheet of this example was excellent in transparency, heat resistance and flexibility.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

The sheet obtained by the production method of the present invention is excellent in transparency, heat resistance and flexibility, and is required in these fields, for example, medical bags such as infusion bags and blood bags, retort bags and the like. It is preferably used as a material for. Especially for medical containers, heat resistance during sterilization, high transparency for observing foreign substances in the content liquid, and prevention of contamination by bacteria in the air during drip or blood transfusion (in a hard container The content of the content liquid does not flow out unless the outside air intake port is provided due to the reduced pressure of 1.), and the sheet of the present invention is particularly preferably used.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus for obtaining a composition sheet in which a propylene copolymer has a smectic crystal structure.

FIG. 2 is a diagram showing an X-ray analysis pattern of a composition sheet in which the crystal structure of a propylene copolymer is 100% smectic crystals.

FIG. 3 is a diagram showing a DSC chart of a composition sheet in which the crystal structure of a propylene copolymer is 100% smectic crystals.

FIG. 4 is a view showing an X-ray analysis pattern of a composition sheet in which a propylene copolymer has a crystal structure of 100% α crystal.

FIG. 5 is a diagram showing a DSC chart of a composition sheet in which the crystal structure of a propylene copolymer is 100% α crystal.

FIG. 6 is a diagram showing a DSC chart of a composition sheet in which a propylene copolymer has various crystal structures.

[Explanation of symbols]

1; Annular slit, 2; Tubular sheet, 3; Air ring, 4; Compressed air inlet pipe, 5; Cooling mandrel, 6; Coolant inlet pipe, 7; Coolant outlet pipe, 8; External coolant tank,
9; External cooling liquid inlet pipe, 10; Overflow pipe, 1
2; elastic material, 13; stabilizer, 14; nip roll

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29K 23:00 B29L 7:00

Claims (2)

[Claims] 1. (A) Propylene having a Q value of 4.5 or less and 1
Crystalline random copolymer 4 with at least one α-olefin
An extruder is used to prepare a composition comprising 5 to 95% by weight of (B) a crystalline homopolymer of (1) 1-butene and / or (2) a hydrogenated product of a styrene block copolymer. The tubular sheet that has been melted and extruded below the annular die is fed with compressed air inside to expand it, and is then placed in the external cooling liquid tank containing the external cooling liquid through its bottom and Cooling the outside of the sheet with the cooling liquid and the inside of the sheet with a cooling mandrel during sliding contact with the outer surface of an internal liquid cooling type cooling mandrel whose contact surface with the grate is cylindrical; Production of a sheet having a smectic crystal structure in which a propylene copolymer in a composition is characterized in that the cooled sheet is led out to the outside below the external cooling liquid tank and folded in a state of being released from the external cooling liquid pressure. Method. 2. (A) Propylene having a Q value of 4.5 or less and 1
Crystalline random copolymer 6 with one or more α-olefins
An extruder was used to prepare a composition comprising 0 to 85% by weight of (B) (1) 1-butene crystalline homopolymer and / or (2) styrene block copolymer hydrogenated product of 15 to 40% by weight. The tubular sheet melted by and extruded downward from the annular die is inflated by sending compressed air into the inside, and then penetrated through the bottom of the tank into an external cooling liquid tank containing an external cooling liquid of 60 ° C. or less. While being contacted and slid on the outer surface of a cooling mandrel having an internal liquid cooling surface temperature of 60 ° C. or less, which is arranged and has a cylindrical contact surface with the sheet, the outside of the sheet is cooled by the cooling liquid. The inside of the sheet is cooled by a cooling mandrel, then the cooled sheet is led out to the lower outside of the external cooling liquid tank, and is folded in a state of being released from the external cooling liquid pressure. Polymer smectic Method for producing a sheet having a structure.