JPH1087921A - Vessel made of olefin polymer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vessel which is transparent without cloudiness, accompanied by no odor and can be suitably used for food products and medical purposes, by combining a crystalline propylene polymer with a specific block copolymer. SOLUTION: A crystalline propylene polymer of which melting point is 120-145 deg.C, in an amount of 95-80wt.% is blended with 5-20wt.% of a hydrogenated diene copolymer which comprises a (A)-(B) block copolymer containing (A) a vinyl aromatic compound polymer block and (B) a conjugated diene polymer or a vinyl aromatic compound - a conjugated diene random copolymer block, or if necessary (A)-(B)-(C) block copolymer, additionally containing (C) taper block in which the vinyl aromatic compound in the vinyl aromatic compound and the conjugated diene is gradually increased, or (A)-(B)-(A) where the weight ratio of the vinyl aromatic compound and/or the conjugated diene is (5-60)(95-40).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a container made of an olefin polymer composition. Specifically, the present invention relates to a container made of an olefin polymer composition which is transparent, has no white appearance, and has no odor.

[0002]

2. Description of the Related Art A container using a propylene polymer has various excellent properties such as rigidity, impact resistance and chemical resistance. On the other hand, there is a problem in transparency such as insufficient transparency and a distinctive white appearance.
It is already known that the transparency of a propylene polymer obtained by random copolymerization with an α-olefin such as ethylene is improved.However, as another technique for improving the transparency of a propylene polymer, an ethylene polymer is added to a propylene polymer. (JP-A-53-79939, JP-A-5-8487)
7, JP-A-5-124092, JP-A-5-24591
1, JP-A-6-31769), a mixture of a propylene polymer and a nucleating agent (JP-A-60-127336), and a polymer of an α-olefin having 6 or more carbon atoms and having a branch at the 3-position in a propylene polymer. What combined a coalescence is known. Compositions according to these techniques have improved transparency (transparency) but a distinctive white appearance. In addition, those containing a nucleating agent often generate extremely unpleasant odors generated from the nucleating agent.

[0003]

SUMMARY OF THE INVENTION The present inventor has made intensive studies to solve various secondary problems associated with improving the transparency of the composition in question in the prior art. As a result, three types of block copolymers (A)-(B), (A)-(B)-(C) or (A)-(B), which will be described later in detail, as a propylene-based polymer composition for forming a crystalline propylene polymer. (A)-(B)-(A) (where (A) is a vinyl aromatic compound polymer block, (B) is a partially hydrogenated conjugated diene polymer or vinyl aromatic compound and A copolymerized block with a diene, wherein the conjugated diene portion is partially hydrogenated;
In which the number of vinyl aromatic compound polymer units is increased as necessary compared to the case of (B)) in the copolymerized block of 5) to 20% by weight of the composition.
It was found that the combination described above eliminates the above-mentioned drawbacks of the known technique (note: whiteness of a molded article, etc.), and based on this finding, the present invention has been reached. As apparent from the above description, an object of the present invention is to provide a container made of an olefin polymer composition which is transparent, has no white appearance, and has no odor.

[0004]

The present invention has the following arrangement. (1) 95 to 80 wt% of a crystalline propylene polymer having a melting point of 120 to 145 ° C., and a partial hydrogenation random of a vinyl aromatic compound polymer block (A) and a conjugated diene polymer or a vinyl aromatic compound and a conjugated diene (A)-(B) block copolymer comprising a copolymer block (B) or, if necessary, a taper block wherein the weight ratio of the vinyl aromatic compound among the vinyl aromatic compound and the conjugated diene gradually increases ( (A)-(B)-
(C) Any one of (A)-(B)-(A) block copolymers comprising a block copolymer or a vinyl aromatic polymer block (A), wherein a vinyl aromatic compound /
A conjugated diene ratio of 5 to 60/95 to 40 by weight,
The weight ratio of the component (A) and, if necessary, the two constituent units is constituted. The bond content of the vinyl aromatic compound in the component (C) is 3 to 50% by weight of all the constituent units. A vinyl aromatic bond content of at least 3% by weight,
The vinyl bond content of the conjugated diene part in the component (B) is 60.
% Of the block copolymer is hydrogenated so that at least 80% of the double bonds of the conjugated diene moiety are saturated;
A container formed by molding an olefin polymer composition containing 5 to 20 wt% of a hydrogenated diene copolymer having a number average molecular weight of 50,000 to 600,000.

(2) The container according to (1), wherein the crystalline propylene polymer has a melt flow rate of 0.5 to 10 g / 10 min.

(3) (A)-(B) block copolymer,
The weight ratio of the vinyl aromatic compound / conjugated diene in the (A)-(B)-(C) block copolymer or (A)-(B)-(A) block copolymer is 5-60 / 95- 4
The container according to the above (1), which is 0.

(4) Structural units of the vinyl aromatic compound are styrene, t-butylstyrene, α-methylstyrene, p
The container according to (1), wherein the container is one or more structural units selected from -methylstyrene, divinylbenzene, 1,1-diphenylstyrene, and N, N-diethyl-p-aminoethylstyrene.

(5) The conjugated diene constituent unit is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3
One or more structural units selected from -pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, 1,3-pentadiene or chloroprene; The container according to (1).

(6) The partially hydrogenated random copolymer block (B) of the vinyl aromatic compound and the conjugated diene has at least 60% of the vinyl bond portion of the copolymer before partial hydrogenation and 80% of the conjugated diene portion. % Or more by hydrogenation.

Hereinafter, the present invention will be described in detail. The crystalline propylene polymer used in the present invention is propylene as a main monomer and a relatively small amount of ethylene as a comonomer,
It is a random copolymer using at least one monomer selected from α-olefins such as 1-butene and 1-hexene.

[0011] The crystalline propylene polymer used in the present invention has a melting point (temperature measured based on JIS K 7121) of 120 to 145 ° C. 145 melting point
If the temperature greatly exceeds ℃, the transparency of the container is insufficient,
Those having a melting point much lower than 120 ° C. are not preferable because of poor heat resistance. The crystalline propylene polymer used in the present invention can be obtained by using a coordination compound catalyst system such as a Ziegler-Natta catalyst and polymerizing a required olefin by a polymerization method such as slurry polymerization or gas phase polymerization. it can. The crystalline propylene polymer used in the present invention has a melt flow rate (MFR) measured at a measurement temperature of 230 ° C. of 0.5 to 10 g / 10 min, preferably 1 to 8 g / 10 min. If the MFR is out of this range, the moldability is poor.

The hydrogenated diene copolymer used in the present invention may be a vinyl aromatic compound polymer block (A) and a conjugated diene polymer or a random copolymer block of a vinyl aromatic compound and a conjugated diene (B). (A)-
(B) a block copolymer, or (A)-(B)-(C) comprising a vinyl aromatic compound and, if necessary, a taper block (C) in which a vinyl aromatic compound among conjugated dienes is gradually increased. (A)-comprising a block copolymer or a vinyl aromatic polymer block (A)
(B)-(A) It is composed of a block copolymer. First, the ratio of vinyl aromatic compound / conjugated diene in all structural units is 5-60 / 95-40, preferably 7-40 / 9 by weight ratio.
It needs to be 3 to 60. (A) according to the present invention
When the content of the vinyl aromatic compound unit in the block or the blocks (B) and (C) is less than 5% by weight, the effect of improving the transparency and whiteness of the container is insufficient. When the content of the vinyl aromatic compound unit exceeds 60% by weight, poor compatibility with the crystalline propylene polymer occurs, and the transparency is deteriorated. The total content of the vinyl aromatic compound in the vinyl aromatic compound polymer block (A) and the optional taper block (C) is 3 to 50% by weight of all the structural units. Preferably 5
40% by weight, particularly preferably 5 to 25% by weight, and the binding content of the vinyl aromatic compound in the component (A) is at least 3% by weight, preferably 3 to 20% by weight.
When the bond content of the component (A) or the vinyl aromatic compound of the component (A) and the component (C) is less than 3% by weight of all the structural units, when the obtained hydrogenated diene copolymer is pelletized, It becomes easy to block, and there is a problem in handling. Furthermore, a random copolymer block (B) of a conjugated diene polymer or a vinyl aromatic compound and a conjugated diene
The vinyl bond content of the conjugated diene moiety therein is in an amount exceeding 60%, preferably 70% or more, and more preferably 8% or more.
0% or more. When the vinyl bond content is 60% or less, compatibility with polypropylene is poor, and transparency is deteriorated. Here, the vinyl bond means a bonding unit in which a conjugated diene compound is polymerized by a double bond at a 1,2- or 3,4-bond position.

Further, the hydrogenated diene copolymer of the present invention contains at least 80%, preferably 90% or more, more preferably 95 to 100% of the double bonds of the conjugated diene portion of the block (B). And less than 80%, the heat resistance is poor. Further, the hydrogenated diene copolymer of the present invention has a number average molecular weight of 50,000 to 60.
10,000, preferably 80,000 to 500,000. Number average molecular weight is 5
If it is less than 10,000, the releasability of the container from the mold at the time of molding deteriorates, and if it exceeds 600,000, the fluidity decreases and partial irregularities occur on the container surface, resulting in a decrease in transparency.

The hydrogenated diene copolymer of the present invention comprises a block (A), a block (B), and, if necessary, a taper block (C) or a block (A), which is an organic alkali metal compound in an organic solvent. Is used as an initiator to carry out living anionic polymerization to obtain a block copolymer, which is then obtained by hydrogenating the block copolymer. Examples of the vinyl aromatic compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene, and vinylpolyzine. And styrene and α-methylstyrene are particularly preferred. Examples of the conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 5-diethyl-
Examples thereof include 1,3-octadiene, 3-butyl-1,3-octadiene, and chloroprene. In order to obtain a hydrogenated diene copolymer which is industrially usable and has excellent physical properties, 1,3-butadiene, Isoprene and 1,3-pentadiene are preferred, and 1,3-butadiene is more preferred.

The block copolymer may be formed by any method, but generally, a polymerization initiator of an alkali metal compound such as an organolithium compound is used in a hydrocarbon organic solvent such as pentane, hexane or heptane. First, block (A) or block (B) is polymerized, and then block (B) or block (A) is polymerized. It does not matter whether the block (A) or the block (B) is polymerized first. Further, the boundary between the block (A) and the block (B) does not necessarily need to be clearly distinguished. To obtain the (A)-(B)-(C) block copolymer or the (A)-(B)-(A) block copolymer, an organic lithium initiator is used in an organic solvent. A block (A) is polymerized by adding an aromatic vinyl compound, and then a conjugated diene or a conjugated diene and an aromatic vinyl compound are added to form a block (B), and further a conjugated diene and an aromatic vinyl compound or an aromatic vinyl compound are added. The tapered block (C) or the block (A) may be polymerized by adding an aromatic group vinyl compound. In this case, first, the taper block (C) or the block (A) is polymerized first, and then the block (B) and then the block (A)
May be polymerized.

The (A)-(B) block copolymer, (A)-(B)-(C) block copolymer or (A)-(B)-(A) block thus obtained The copolymer may be a block copolymer having a polymer molecular chain extended or branched as represented by the following general formula by adding a coupling agent. [(A)-(B)] nX, [(A)-(B)-
(C)] nX or [(A)-(B)-(A)] n
-X (wherein (A), (B) and (C) are the same as above, and n is 2
４4 positive numbers, X represents a coupling agent residue. )

The hydrogenated diene copolymer of the present invention is obtained by dissolving the block copolymer thus obtained in an inert solvent, at 20 to 150 ° C. and under a hydrogen pressure of 1 to 100 kg · cm ² . In the presence of a hydrogenation catalyst. Inert catalysts used for hydrogenation include hydrocarbon solvents such as hexane, heptane and cyclohexane, or polar solvents such as methyl ethyl ketone, ethyl acetate, ethyl ether and tetrahydrofuran. Remove catalyst residues from the hydrogenated block copolymer solution, add a phenolic or amine antioxidant, and easily isolate the hydrogenated diene copolymer from the polymer solution Can be. Isolation of a hydrogenated diene-based copolymer is performed, for example, by a method in which acetone or alcohol is added to the copolymer solution to cause precipitation, a method in which the polymer solution is poured into boiling water with stirring, and the solvent is distilled off. Can be. The amount of the hydrogenated diene copolymer used in the present invention is in the range of 5 to 20% by weight based on the whole composition. If the amount is less than 5% by weight, the improvement in whiteness is insufficient. Even if the amount is 20% by weight or more, no further improvement in whiteness and transparency is observed, and the releasability is rather deteriorated. Therefore, it is not preferable.

The olefin polymer composition of the present invention may contain an antioxidant and the like in addition to the above-mentioned components within a range that does not substantially impair the effects of the present invention. The olefin polymer composition of the present invention comprises the above components in a Henschel mixer (trade name), a super mixer (trade name),
Mixing with a mixing device such as a ribbon blender and a tumbler mixer, and when melt kneading is required, pelletization using a usual single-screw extruder or twin-screw extruder can also be exemplified. Melt kneading temperature is generally 180 to
The temperature is 300C, preferably 190-250C. The container using the resin composition of the present invention can be obtained by a direct blow molding method, a stretch blow (stretch blow) molding method, or the like.

[0019]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited by these specific examples. Evaluation of the characteristics used in the following Examples and Comparative Examples was performed by the following methods. (1) Melting point: Measured based on JIS K 7121 (2) 230 ° C melt flow rate (MFR): JIS
K 7210 (1976) test condition 14 (230
° C, measured value based on 2.16 kgf), unit: g / 10
min (3) Transparency: The haze value of a 1 mm thick flat plate formed by injection molding was measured according to ASTM D1003. The smaller the value, the better the transparency. (4) White feeling: molded by a direct blow molding machine,
Internal volume about 700ml, average wall thickness of container body about 0.5mm
The hollow container was visually observed, and the sample having no white appearance was evaluated as ○, and the sample with slight whiteness was evaluated as ×. (5) Odor: A container having an internal volume of about 700 ml formed by a direct blow molding machine was presented to ten testers, and the degree of odor was determined. ：: No odor or very slight odor and no discomfort was felt at all. ×: 6 or more persons judged unpleasant odor. (6) Moldability: Separation of blow molded container from mold. It was evaluated by its moldability. When the molded product naturally dropped from the mold when the blow mold was released, it was evaluated as ○, and when it did not fall, as ×.

Examples 1 to 7 and Comparative Examples 1 to 7 To the resins and nucleating agents shown in Table 1, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) was used as an antioxidant. )] methane 0.1% by weight and hydrotalcite [Mg4.5Al ₂ (OH) ₁₃ C
O ₃ · 3.5H ₂ O] was added to 0.05% by weight were uniformly mixed by a Henschel mixer (trade name), to obtain a melt-kneaded pellets composition in an extruder. Using this composition as a raw material, a direct blow molding machine [trade name: Placo SN-50A (manufactured by Placo)] was used to obtain an extrusion temperature of 1
Approximately 700 m in internal volume under molding conditions of 90 ° C and mold temperature of 20 ° C
1. A hollow container having an average body thickness of about 0.5 mm was formed.
Table 1 shows the characteristics of the hollow container.

[Table 1]

[0021]

The hollow container made of a polyolefin resin of the present invention is optimal for food and medical containers because it has no white sensation, is excellent in transparency, and has no odor.

Claims (6)

[Claims] 1. A crystalline propylene polymer having a melting point of 120 to 145 ° C., 95 to 80% by weight, a partial hydrogen of a vinyl aromatic compound polymer block (A) and a conjugated diene polymer or a vinyl aromatic compound and a conjugated diene. (A)-(B) block copolymer comprising an added random copolymer block (B) or, if necessary, a taper in which the weight ratio of the vinyl aromatic compound among the vinyl aromatic compound and the conjugated diene gradually increases (A)-(B)-(C) block copolymer comprising block (C) or (A)-(B)-(A) block copolymer comprising vinyl aromatic polymer block (A) Wherein the weight ratio of the vinyl aromatic compound / conjugated diene is 5 to 60/95 to 40, and the weight ratio of the component (A) and, if necessary, the two structural units is That (C)
The content of the vinyl aromatic compound in the component is 3 to 50% by weight of the total constituent units, the content of the vinyl aromatic bond in the component (A) is at least 3% by weight, and the content of the conjugated diene moiety in the component (B) is A block copolymer having a vinyl bond content of more than 60% is hydrogenated to obtain a hydrogenated diene copolymer having at least 80% of the double bonds of the conjugated diene portion saturated and having a number average molecular weight of 50,000 to 600,000. A container formed by molding an olefin polymer composition containing 5 to 20% by weight of a polymer. 2. The container according to claim 1, wherein the melt flow rate of the crystalline propylene polymer is 0.5 to 10 g / 10 min. 3. (A)-(B) a block copolymer,
The weight ratio of the vinyl aromatic compound / conjugated diene in the (A)-(B)-(C) block copolymer or (A)-(B)-(A) block copolymer is 5-60 / 95- 4
2. The container according to claim 1, wherein the value is 0. 4. The vinyl aromatic compound structural unit is styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene or N, N-diethyl-p-aminoethyl. 2. The composition according to claim 1, which is one or more structural units selected from styrene.
A container according to claim 1. 5. The conjugated diene constituent unit is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3 The container according to claim 1, wherein the container is at least one structural unit selected from -hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, 1,3-pentadiene, and chloroprene. . 6. A partially hydrogenated random copolymer block (B) of a vinyl aromatic compound and a conjugated diene, wherein at least 60% of the vinyl-bonded portion and 80% of the conjugated diene portion of the copolymer before the partial hydrogenation. The container according to claim 1, wherein the above is obtained by hydrogenation.