JP2000226491A - Block copolymer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer material having excellent characters required for a material of rubber sealing articles for medicine and medical treatment, and good molding processability. SOLUTION: This block copolymer compsn. is obtd. by mixing a block copolymer (I) comprising an aromatic vinyl compd. polymer block and an isobutylene polymer block and having a max. peak mol.wt. by GPC of not smaller than 50,000 and not greater than 200,000, and a block copolymer (II) comprising an aromatic vinyl compd. polymer block and an isobutylene polymer block and having a max. peak mol.wt. by GPC of not smaller than 10,000 and not greater than 50,000, has a (I)/(II) weight ratio of 10/90-90/10, and in GPC of the compsn., total time required from the beginning of elution to the end of the elution (t), elution time of the max. peak of GPC for (I) (i), and elution time of the max. peak of GPC for (II) (ii), satisfy the condition shown by the expression: [(ii)-(i)]/(t)>=0.05.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block copolymer composition which is excellent in melt fluidity and molding processability, and is excellent in rubber properties such as mechanical properties and compression set, and a molded article and a seal made of the composition. About materials. The block copolymer composition of the present invention has moldability, mechanical properties, flexibility,
Excellent properties such as elastic recovery, gas barrier properties, sealing properties, safety, hygiene, etc., and molded articles made of the composition are used as sealing materials such as sealing materials, gaskets, and packing materials to achieve the above-mentioned properties. Excellent properties are exhibited effectively.

[0002]

2. Description of the Related Art Conventionally, as sealable articles for medicines and medical care, rubber stoppers for pharmaceutical containers, gaskets for syringes, rubber stoppers and caps for blood collection under reduced pressure, butyl rubber, natural rubber, polyisoprene rubber, styrene-butadiene copolymer have been used. Manufactured from rubber materials such as rubber. These rubber materials satisfy characteristics such as gas barrier property, non-elution property, sterilization resistance, needle stick resistance, self-sealing property, etc., required for pharmaceutical and medical sealable articles, and It is generally vulcanized in form. To manufacture the article,
The rubber material and a sulfur-based vulcanizing agent (sulfur, vulcanization accelerator, other auxiliaries) or an organic peroxide are mixed using a mixer such as a roll or an internal mixer, and then the obtained mixture (compounded rubber) Vulcanization under pressure or vulcanization after molding. In order to produce a desired article in the above steps, large-scale equipment is required due to the vulcanization step, and it takes a long time to go through a complicated step, and the productivity is poor. . further,
Various rubber chemicals are added to the obtained product, so that they are eluted, burrs and vulnerabilities cannot be reused due to vulcanization, and sulfur vulcanizing agents are used. In this case, there is a public health problem that sulfur dioxide gas is generated when the used article is incinerated.

As a means for solving the above-mentioned problems, a medical / medical sealable rubber article comprising a block copolymer of an aromatic vinyl compound and isobutylene has been proposed (JP-A-56-53173; JP-A-5-2121
04, JP-A-5-295053, etc.). When an article is produced using the block copolymer, it is said that an article which can satisfy required properties without vulcanization can be obtained.

[0004]

However, in the above block copolymer of an aromatic vinyl compound and isobutylene, the performance required as a sealable rubber article for medicine and medical use, particularly self-sealing and anti-sealing properties, is required. It is usually difficult to achieve both physical properties such as needlestick properties and resistance to liquid leakage in the heat sterilization step and molding workability. That is, in order to obtain an article having good physical properties close to a vulcanized rubber, it is preferable to use a relatively high molecular weight block copolymer of an aromatic vinyl compound and isobutylene. Since the block copolymer has a very high melt viscosity and greatly reduces the molding processability such as press molding and injection molding, it has a good shape when using such a high molecular weight block copolymer. It becomes difficult to obtain a molded product.

The present invention relates to a polymer material using a block copolymer of an aromatic vinyl compound and isobutylene, which has a gas barrier property and non-gas barrier property required for a material of a sealable rubber article for medicine and medical use. To provide a polymer material having excellent properties such as dissolution property, liquid leakage resistance during heat sterilization, sterilization resistance, needle stick resistance, and self-sealing property, and also having good moldability. That is the task. Another object of the present invention is to provide a molded article and a sealing material (such as a medical / medical sealing material) in which the excellent properties of the polymer material are effectively exhibited.

[0006]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that a block copolymer of an aromatic vinyl compound and isobutylene having two or more kinds having different molecular weights is used. If the combination of the block copolymers used satisfies certain conditions in the polymer composition produced in combination with the above, gas barrier properties, non-elution properties, liquid leakage resistance during heat sterilization, sterilization resistance Nature, needlestick resistance,
Excellent in various physical properties such as self-sealing, and press molding,
They have found that they have good moldability in injection molding and the like, and have completed the present invention.

That is, the present invention firstly provides:

(1) A block copolymer comprising an aromatic vinyl compound-based polymer block and an isobutylene-based polymer block and having a maximum peak molecular weight in a gel permeation chromatograph of 50,000 or more and 200,000 or less. At least one of (I),
And a block copolymer (II) comprising an aromatic vinyl compound-based polymer block and an isobutylene-based polymer block, and having a maximum molecular weight in a gel permeation chromatograph of 10,000 or more and less than 50,000. A block copolymer composition obtained by mixing at least one kind,

(2) The ratio of the total content of the block copolymer (I) to the total content of the block copolymer (II) is as follows:
(I) / (II) weight ratio of 10/90 to 90/1
0, and

(3) In a gel permeation chromatograph of the composition, the total required time (t) from the start of elution to the end of elution of the block copolymer (I) and the block copolymer (II). And the elution time (i) of the maximum peak in the block copolymer having the lowest molecular weight showing the maximum peak in the block copolymer (I) and the molecular weight showing the maximum peak in the block copolymer (II) are The difference from the elution time (ii) of the highest peak in the highest block copolymer is expressed by the formula

[0011]

[(Ii) − (i)] / (t) ≧ 0.05

This is a block copolymer composition that satisfies the following conditions.

The present invention also provides, secondly, a molded article comprising the above block copolymer composition.

Furthermore, the present invention thirdly provides a sealing material comprising the above-mentioned block copolymer composition.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The block copolymer composition of the present invention is produced by mixing one or more of the above block copolymers (I) and one or more of the above block copolymers (II). Each of the block copolymers (I) and (II) has an aromatic vinyl compound-based polymer block (a) and an isobutylene-based polymer block (b).

The above aromatic vinyl compound-based polymer block
(a) is a polymer block mainly composed of a structural unit derived from an aromatic vinyl compound, and may optionally have a small amount of a structural unit derived from another copolymerizable monomer. Aromatic vinyl compound polymer block (a)
Examples of the structural unit derived from the aromatic vinyl compound constituting styrene, α-styrene, β-styrene, p-methylstyrene, t-butylstyrene, 2,
4,6-trimethylstyrene, monofluorostyrene,
Examples of one or more structural units derived from an aromatic vinyl compound such as difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, indene, and acetonaphthylene can be given, and among them, derived from styrene. It is preferable that the structural unit is mainly used. When the aromatic vinyl compound-based polymer block (a) has a structural unit derived from another copolymerizable monomer together with a structural unit derived from the aromatic vinyl compound, the other copolymer is used. The ratio of the structural units derived from the polymerizable monomer is the ratio of the aromatic vinyl compound-based polymer block.
It is preferably at most 30% by weight based on the weight of (a), more preferably at most 10% by weight. In this case, examples of the other copolymerizable monomer include one or more cationically polymerizable monomers such as 1-butene, pentene, hexene, butadiene, isoprene, and methyl vinyl ether. .

The isobutylene-based polymer block (b) is a polymer block mainly composed of a structural unit derived from isobutylene. In some cases, a small amount of a structural unit derived from another copolymerizable monomer is used. It may be contained. When the isobutylene-based polymer block (b) has a structural unit derived from another copolymerizable monomer together with a structural unit derived from isobutylene, it is derived from the other copolymerizable monomer. Is 30% by weight based on the weight of the isobutylene-based polymer block (b).
Or less, more preferably 10% by weight or less. In this case, examples of the other copolymerizable monomer include one or more cationically polymerizable monomers such as 1-butene, pentene, hexene, butadiene, isoprene, and methyl vinyl ether. .

In the block copolymers (I) and (II), the aromatic vinyl compound-based polymer block (a) is usually used in view of the gas barrier properties and mechanical properties of the obtained block copolymer composition. And the ratio of the isobutylene-based polymer block (b) is 5 / (b) in the weight ratio of (a) / (b).
It is preferably in the range of 95 to 80/20, and 10
More preferably, it is in the range of / 90 to 70/30.

In the block copolymers (I) and (II), it is sufficient that the aromatic vinyl compound-based polymer block (a) and the isobutylene-based polymer block (b) are bonded in a block shape. The number and the connection form of the blocks (a) and (b) are not particularly limited. Examples of the bonding form of the blocks (a) and (b) in the block copolymers (I) and (II) include those represented by the following formulas (X), (Y) or (Z). .

[0021]

Ab (X) a- (ba) m (Y) b- (ab) n (Z)

(In the above formula, a represents an aromatic vinyl compound-based polymer block (a), b represents an isobutylene-based polymer block (b), and m and n each represent an integer of 1 or more (for example, 1 to 1). Represents an integer within the range of 5.)

Among the block copolymers represented by the formulas (X), (Y) and (Z), in the present invention, the block copolymers (I) and (II) are represented by the formula (Y) A block copolymer corresponding to the case where m is 1, that is, a block arrangement of an aromatic vinyl compound-based polymer block (a) -isobutylene-based polymer block (b) -aromatic vinyl compound-based polymer block (a) It is preferable to use a triblock copolymer having the following formulas in terms of handleability, easy availability, mechanical properties of the obtained composition, and the like.

The block copolymer (I) and the block copolymer (II) used together in the block copolymer composition of the present invention are distinguished from each other in terms of the molecular weight showing the maximum peak in gel permeation chromatography. Is done. That is, the molecular weight is in the range of 50,000 or more and 200,000 or less for the block copolymer (I), and is in the range of 10,000 or more and less than 50,000 for the block copolymer (II). Block copolymer (I) alone or two or more types of block copolymers (I)
In the composition prepared only from the composition, the melt viscosity becomes too high, and the moldability decreases. In addition, the block copolymer (II) alone or two or more types of block copolymers (II)
In the composition prepared from the composition alone, the value of the compression set becomes large, and for example, when the molded article is used as a stopper, sufficient performance cannot be obtained in terms of liquid leakage resistance at the time of heat sterilization. When a block copolymer having a maximum peak molecular weight of more than 200,000 in gel permeation chromatography is used instead of the block copolymer (I), the melt viscosity of the obtained composition becomes too high, and Poor sex. When a block copolymer having a maximum peak molecular weight of less than 10,000 in gel permeation chromatography is used instead of the block copolymer (II), the resulting composition has insufficient rubber properties. .

In the present invention, the molecular weight of the block copolymer (I) having a maximum peak in a gel permeation chromatograph of 55,000 or more and 1 to 5 from the viewpoint of the balance between the physical properties of the composition obtained and the moldability.
It is more preferable to use those having a molecular weight in the range of 90000 or less, and those having a molecular weight showing the maximum peak in gel permeation chromatography of 15,000 or more and 45,000 or less as the block copolymer (II). It is more preferable to use.

In the block copolymers (I) and (II), the aromatic vinyl compound-based polymer block
The number average molecular weight of (a) is in the range of 2,500 to 50,000, the number average molecular weight of the isobutylene-based polymer block (b) is in the range of 5,000 to 100,000, and the number average molecular weight of the entire block copolymer is 10,000-200
It is preferably in the range of 000. For the block copolymers (I) and (II), the ratio between the weight average molecular weight Mw and the number average molecular weight Mn was Mw / Mn.
Is preferably in the range of 1.0 to 2.0. In addition, the block copolymers (I) and (II)
In some cases, a halogen atom such as a chlorine atom or a bromine atom, or a functional group such as a carboxyl group, a hydroxyl group, an acid anhydride group, or an epoxy group may be provided in the middle and / or at the end of the molecular chain.

Block copolymer (I) used in the present invention
In (II) and (II), there is no particular limitation on the production method, acquisition method, and the like. Although not particularly limited, as a method for producing the block copolymers (I) and (II), conventionally known methods can be employed. For example, in the presence of an initiator system composed of a Lewis acid and an organic compound capable of forming a cationic polymerization active species in combination therewith, if necessary, in the presence of an additive such as a pyridine derivative or an amide, hexane is added. In an inert solvent such as methylene chloride, the polymerization step of a monomer mainly composed of an aromatic vinyl compound and the polymerization step of a monomer mainly composed of isobutylene are carried out stepwise in an arbitrary order to carry out each polymer block. By successively forming (a) and (b), block copolymers (I) and (II) having a desired block arrangement can be produced, respectively. Examples of the above-mentioned Lewis acid include titanium tetrachloride, boron trichloride, aluminum chloride, tin tetrachloride and the like. Examples of the organic compound capable of forming a cationic polymerization active species include an alkoxy group and an acyloxy group. And organic compounds having a functional group such as a halogen atom, and specific examples thereof include bis (2-methoxy-2-propyl) benzene, bis (2-acetoxy-2-propyl) benzene, and bis (2-chloro-2-propyl). ) Benzene and the like can be mentioned. Further, as the above amides, for example,
Examples thereof include dimethylacetamide and dimethylformamide.

More specifically, for example, a triblock having a block arrangement of an aromatic vinyl compound polymer block (a) -isobutylene polymer block (b) -aromatic vinyl compound polymer block (a) The copolymer is prepared, for example, by first using an organic compound having one functional group in a molecule and a Lewis acid as an initiator system, and first polymerizing a monomer mainly composed of an aromatic vinyl compound in the polymerization system. After the polymerization reaction is substantially completed, a monomer mainly composed of isobutylene is added to the polymerization system and polymerized.After the polymerization reaction is substantially completed, again, mainly It can be produced by a method in which a monomer comprising an aromatic vinyl compound is added to a polymerization system and polymerized. Further, apart from the above-mentioned method, a monomer mainly composed of isobutylene is polymerized using an organic compound having two functional groups in a molecule and a Lewis acid as an initiator system, and the polymerization is substantially completed. After that, by supplying a monomer mainly composed of an aromatic vinyl compound, it is possible to polymerize a monomer mainly composed of an aromatic vinyl compound at both ends of the molecular chain of the previously formed isobutylene-based polymer, By this method, aromatic vinyl compound-based polymer block (a) -isobutylene-based polymer block (b) -aromatic vinyl compound-based polymer block
It is also possible to produce a triblock copolymer having the block arrangement of (a).

The block copolymer composition of the present invention contains at least one type of block copolymer (I) and at least one type of block copolymer (II). In the composition of the present invention, the ratio of the total amount of the block copolymer (I) to the total amount of the block copolymer (II) contained therein is determined from the viewpoint of compatibility between rubber properties and molding processability. In a weight ratio of I) / (II),
It is necessary to be within the range of 10/90 to 90/10, and more preferably within the range of 20/80 to 80/20.

In the block copolymer composition of the present invention, the elution time (i) of the maximum peak in the block copolymer (I), which shows the maximum peak in gel permeation chromatography and has the lowest molecular weight, is shown. ) And the elution time (ii) of the maximum peak in the block copolymer (II) having the highest molecular weight showing the maximum peak in gel permeation chromatography (i.e., (ii)-(i)) Value)
Block copolymer (I) and block copolymer (II) in the gel permeation chromatograph of the composition
Is 0.05 or more times the total time (t) required from the start of elution to the end of elution, that is, the value of the formula [(ii)-(i)] / (t) is 0. 0.05 or more. If it is less than 0.05, the moldability of the block copolymer composition is reduced,
Alternatively, rubber properties such as compression set are reduced. The “block copolymer (I) having the lowest molecular weight showing the maximum peak in gel permeation chromatography among the block copolymers (I)” means that only one type of block copolymer (I) is used. If there is one to use
Means the type of the block copolymer (I) itself, and when two or more types of the block copolymer (I) are used, of the types corresponding to the block copolymer (I), It means one kind having the lowest molecular weight showing the maximum peak. On the other hand, the above “block copolymer (II) having the highest molecular weight showing the maximum peak in gel permeation chromatography” refers to only one type of block copolymer (II) used. In some cases, it means one kind of the block copolymer (II) used, and when two or more kinds of the block copolymer (II) are used, the block copolymer (II) is used. ) Means one kind having the highest molecular weight showing the maximum peak.

The above elution time (i) and elution time (i
As i), it is preferable to adopt the value of the elution time determined from the gel permeation chromatograph of the corresponding block copolymer alone, but based on the gel permeation chromatograph of the block copolymer composition. It can also be grasped as the elution time at the maximum value of each corresponding peak. When the elution times (i) and (ii) are determined based on the gel permeation chromatograph of the block copolymer composition, when the maximum values of the corresponding peaks are sufficiently separated,
What is necessary is just to obtain the elution time corresponding to the maximum value,
When the peak of one peak overlaps the other peak and it is difficult to confirm the maximum value of the peak, an elution time corresponding to the inflection point in the peak curve may be adopted.

The block copolymer composition of the present invention may contain an inorganic filler, if necessary, as long as the effects of the present invention are not impaired. When an inorganic filler is contained, the cost can be reduced by the effect of increasing the amount of the inorganic filler, and in some cases, it functions to improve the quality of the block copolymer composition. Examples of the inorganic filler include, for example, calcium carbonate, carbon black (channel black, furnace black, etc.), talc, magnesium hydroxide, mica, barium sulfate, natural silicic acid, white carbon, titanium oxide, and the like. These inorganic fillers may be used alone or in combination of two or more. In addition, the block copolymer composition of the present invention may contain a pigment, a colorant, a flame retardant, an ultraviolet absorber, an antioxidant, an antistatic agent, and a lubricant, if necessary, as long as the effects of the present invention are not impaired. And one or more other additives such as a release agent such as silicone oil.

In the block copolymer composition of the present invention, one or more block copolymers (I) and one or more block copolymers (II) are mixed together with additives as required. Can be prepared. The mixing is usually performed under the conditions of melt-kneading the block copolymers (I) and (II), and the melt-kneading is usually performed by melt-kneading using a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or the like. A melting and kneading apparatus as used can be used. The conditions of the melt-kneading can be appropriately selected according to the type of the block copolymer to be used, the type of the apparatus, and the like. Usually, the temperature is in the range of 180 to 280 ° C. for about 1 to 15 minutes. Is adopted. In the obtained block copolymer composition, the above formula [(ii)-
Satisfying the condition that (i)] / (t) is 0.05 or more is based on gel permeation chromatograph data (elution start time, maximum peak elution time) for each block copolymer used alone. , Elution end time, etc.) can be easily achieved experimentally.

The form of the block copolymer composition of the present invention is not particularly limited, but is preferably in the form of pellets when used as a molding material.

The block copolymer composition of the present invention is thermoplastic and can be easily molded by using a molding method and a molding apparatus generally employed for thermoplastic polymers. Various molded products having arbitrary shapes and dimensions can be manufactured by melt molding methods such as injection molding, extrusion molding, press molding, and blow molding.

In particular, the block copolymer composition of the present invention has excellent moldability, gas barrier properties, compression set resistance, sealing properties, sealing properties, flexibility, mechanical properties,
It has excellent properties in oil resistance, safety, hygiene, etc., so it can be effectively used as a molding material not only for general-purpose molded products such as bands and grips, but also for sealing materials such as sealing materials, packing materials and gaskets. Can be used. Among the sealing materials, sealing materials for medical instruments (for example, plugs for medical containers, gaskets for syringes, sealing materials or packing materials for vacuum blood collection tubes), and sealing materials in the field of handling food (for example, food production) -It can be used very effectively as various sealing materials for processing equipment and various sealing materials for containers for storing and / or storing food. Note that the shape, structure, size, and the like of the sealing material can be appropriately set according to the respective applications.

[0037]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

The number average molecular weight (Mn) and molecular weight distribution (Mw (weight average molecular weight) /
Mn (number average molecular weight) and GPC (gel permeation chromatography) of the block copolymer composition were measured under the following conditions using standard polyisobutylene as an index.

Apparatus: Liquid chromatograph LC-6A (manufactured by Shimadzu Corporation) Eluent: tetrahydrofuran Flow rate: 1 ml Temperature: 55 ° C. Column: shim-pack GPC 802, 80
4,806 (manufactured by Shimadzu Corporation) Detector: Differential refractive index detector

The gel permeation chromatograph obtained in the block copolymer composition was prepared in order to reduce errors in the analysis process.
After setting corrected baselines L1 ″ and L2 ″, the total required time (t) for elution was determined as follows. The distance (D1) between a straight line (L1) obtained by extending the baseline on the low molecular weight side of the gel permeation chromatograph and a straight line (L1 ′) parallel to L1 and in contact with the peak of the largest peak is obtained. I asked. A straight line (L1 ″) that is parallel to L1 and is located between the straight line (L1 ′) that is in contact with the peak and that has a distance of 0.01 × D1 from L1 is drawn. The point on the lowest molecular weight side among the intersections of the peak and the peak was designated as A. Similarly, a distance (D2) between a straight line (L2) obtained by extending the baseline on the high molecular weight side and a straight line (L2 ′) parallel to L2 and in contact with the peak of the largest peak is obtained. Was. The L2
And a distance (D2) from a straight line (L2 ′) that is parallel to the peak portion. Parallel to L2, located between L2 and L2 'and having a distance from L2 of 0.01
A straight line (L2 ″) of × D2 was drawn. The point on the highest molecular weight side among the intersections of the L2 ″ and the peaks was designated as B. The absolute value of the difference between the elution time at point A and the elution time at point B was taken as (t).

In the following Examples, evaluation of the moldability of the block copolymer composition; surface hardness, tensile strength at break, tensile elongation at break, 100% modulus, permanent elongation, compression set, and Measurement or evaluation of gas permeability; evaluation of liquid leakage of a plug obtained from the composition, coring performance and liquid leakage after needle puncture; and foaming of a syringe gasket obtained from the composition, The tests or measurements of ΔpH, Δpotassium permanganate consumption and evaporation residue are as follows (1) to
This was performed by the method shown in (7).

(1) Moldability of block copolymer composition:
Test for evaluation of plate-like moldability using a block copolymer composition and a cylinder temperature of 210 ° C. and a mold temperature of 40 ° C. using an 80-ton injection molding machine manufactured by Nissei Plastic Industry Co., Ltd. Piece (Dimensions: length x width x thickness = 80mm x 8
(0 mm × 3.2 mm), and the fluidity of the composition and the surface condition of the molded product at that time were visually observed to evaluate the moldability according to the following three-level evaluation criteria. That is, when the flowability of the molten composition is good, a molded product having the same shape and dimensions as the mold is obtained, and the surface of the molded product is smooth, it is judged as “good (（)”, The flowability of the composition obtained is good, and a molded article having almost the same shape and dimensions as the mold can be obtained. However, if the surface of the molded article is not smooth, it is judged as “Normal (△)” and the molten composition is obtained. Was poor (×) when a molded article having the same shape and dimensions as the mold was not obtained due to poor fluidity.

(2) Surface hardness of molded article: The surface hardness of the test piece for evaluating formability was determined according to JIS-K630.
It measured according to 1.

(3) Tensile rupture strength, tensile rupture elongation, 100% modulus and permanent elongation of a molded article: Using a block copolymer composition, an 80-ton injection molding machine manufactured by Nissei Plastics Industry Co., Ltd. A No. 3 dumbbell test piece was injection molded under the conditions of a cylinder temperature of 210 ° C. and a mold temperature of 40 ° C. Using the dumbbell specimen, JIS-
According to K6301, tensile strength at break, tensile elongation at break, 1
The 00% modulus and permanent elongation were measured.

(4) Compression set of molded article: Using the above test piece for evaluating formability, according to JIS-K6301,
The compressive deformation strain when left for 22 hours at a temperature of 70 ° C. and an amount of compressive deformation of 25% was measured.

(5) Gas permeability of molded article: using block copolymer composition, temperature 200 ° C., press pressure 100
A film having a thickness of 20 μm was prepared by press molding under the condition of kg / cm ² , and the permeation of oxygen gas was measured using a gas permeability tester (“GTR-10” manufactured by Yanagimoto Co., Ltd.). The coefficient was measured according to ASTM D3985. It can be evaluated that the smaller the value of the permeability coefficient, the lower the gas permeability, that is, the more excellent the gas barrier property.

(6) Evaluation of plug performance: (i) Liquid leakage resistance: Using the block copolymer composition,
Press molding was performed under the conditions of a melting temperature of 200 ° C. and a pressing pressure of 100 kg / cm ² , and the diameter × length = 2 cm × 2c
m was manufactured. After filling 500 ml of water into a transparent glass bottle having an inner volume of 500 ml, a stopper was inserted into the mouth of the bottle and sealed. This bottle was put into a pressure cooker, heated at 120 ° C. for 60 minutes, and then taken out.
The presence or absence of liquid leakage at the mouth of the bottle was visually observed.

(Ii) Coring property: diameter × length = 2 cm × 2 cm in the same manner as in the evaluation of the liquid leakage resistance (i) described above.
Was manufactured. After filling the same transparent glass bottle used in (i) above with 500 ml of water, a stopper was inserted into the mouth of the bottle and sealed. Further, an aluminum cap was wound over the plug at the mouth of the bottle, and the central portion of the upper surface of the aluminum cap was removed in a circular shape, thereby exposing a part of the surface of the plug. The operation of inserting the standard injection needle (22G) from the vicinity of the center of the exposed surface of the stopper was repeated while shifting the position, whereby the injection needle was penetrated the stopper 10 times in total. The number of the block copolymer composition pieces separated from the stopper and floating in the water by the penetration of the injection needle was counted, and the coring property was evaluated based on the number. In the evaluation of the coring property, it can be determined that the smaller the number of the composition pieces floating in the water, the better the coring property.

(Iii) Leakage after needle puncture: Diameter x length = 2 cm x in the same manner as in the evaluation of liquid leak resistance (i) above.
A 2 cm cylindrical plug was manufactured. After filling the same transparent glass bottle used in (i) above with 500 ml of water, a stopper was inserted into the mouth of the bottle and sealed.
A syringe needle (22G) is penetrated into the bottle from outside the surface of the stopper, and an air needle (22G) is separately penetrated into the bottle from outside the surface of the stopper, and then the bottle is inverted and the water in the bottle is inverted. The water in the bottle was allowed to flow out through a syringe needle until the water content became 150 ml. Next, the injection needle was withdrawn while the bottle was in an inverted state, and the outflow of water at that time was visually observed. Based on the presence or absence of outflow of water at this time, the liquid leakage after needle puncture was evaluated. In the evaluation of the liquid leakage after needle piercing, it can be determined that the sealing performance after needle piercing of the stopper is good when there is no outflow of water when or after the injection needle is pulled out.

(7) Performance evaluation of syringe gasket:
Using the block copolymer composition, press molding was performed under the conditions of a temperature of 200 ° C. and a pressing pressure of 100 kg / cm ² to produce a gasket for a syringe. This is fixed to the tip of the operating rod (piston rod), and a syringe (syringe)
Was inserted inside an outer cylinder (capacity: 10 ml, average inner diameter: 15.5 mm, made of polypropylene). Using the syringe thus prepared, according to the eluate test method described in the 12th revised Japanese Pharmacopoeia "rubber stopper test method for infusion",
Tests or measurements of lathering, △ pH, カ リ ウ ム potassium permanganate consumption and evaporation residue were performed.

(I) Foaming property: In this foaming test,
The shorter the defoaming time is, the better the foaming resistance is, and if the foaming property is within 3 minutes, the gasket is acceptable as a syringe gasket.

(Ii) ΔpH: In this test, the smaller the ΔpH value, the smaller the amount of eluate from the syringe gasket and the higher the safety. Passed as a syringe gasket.

(Iii) Potassium permanganate consumption:
In this test, it is shown that the smaller the value of potassium permanganate consumption is, the smaller the amount of leaching from the gasket for syringe is and the higher the safety is.If the value of potassium permanganate consumption is 2.0 ml or less, Passed as a medical syringe gasket.

(Iv) Evaporation residue amount: In this test, it is shown that the smaller the evaporation residue amount, the smaller the amount of eluate from the syringe gasket and the higher the safety. If the value of the evaporation residue amount is 2.0 mg or less, Passed as a medical syringe gasket.

The block copolymer used in the examples is as follows.

(1) SIBS-1: styrene-isobutylene-styrene triblock copolymer [molecular weight showing maximum peak in gel permeation chromatography = 78,000, number average molecular weight = 75,000, molecular weight distribution (Mw / Mn) = 1 1.1, styrene unit content = 30% by weight]

(2) SIBS-2: styrene-isobutylene-styrene triblock copolymer [molecular weight showing maximum peak in gel permeation chromatograph = 47000, number average molecular weight = 45000, molecular weight distribution (Mw / Mn) = 1 1.1, styrene unit content = 30% by weight]

(3) SIBS-3: styrene-isobutylene-styrene triblock copolymer [molecular weight showing maximum peak in gel permeation chromatography = 55000, number average molecular weight = 52,000, molecular weight distribution (Mw / Mn) = 1] 1.1, styrene unit content = 30% by weight]

Examples 1-4 Styrene-isobutylene-styrene triblock copolymers SIBS-1 and SIBS-1
Each pellet of BS-2 was dry-blended at a predetermined weight ratio shown in Table 1 below, and a cylinder temperature of 2 was obtained using a twin-screw extruder ("BT-30" manufactured by Plastics Industrial Research Institute).
After melt-kneading at 30 ° C. and a screw rotation speed of 150 rpm, the mixture was pelletized to produce a pelletized block copolymer composition. Based on the gel permeation chromatograph of the obtained composition, the above [(ii)-
(I)] / (t) was determined. In this example, SIBS-1 and SIBS-2 correspond to the block copolymers (I) and (II) in the present invention, respectively.
Corresponds to. Using the obtained composition, test pieces, films, plugs, and gaskets for syringes for moldability evaluation or various physical property tests were produced by the above-described methods, respectively. , Tensile breaking strength, tensile breaking elongation, 100% modulus, permanent elongation,
Compression set and gas permeability), stopper evaluation (liquid leakage resistance, coring performance and liquid leakage after needle puncture) and syringe gasket evaluation (foaming, pH, potassium permanganate consumption and evaporation) Residue amount) was performed in the manner described above. Table 1 shows the obtained results.

[0060]

[Table 1]

COMPARATIVE EXAMPLE 1 Pellets of styrene-isobutylene-styrene triblock copolymer SIBS-1 were used alone for testability of moldability, for test pieces for various physical property tests, for films, plugs, and syringes. Each gasket was manufactured by the method described above, and the moldability was evaluated and the molded product was evaluated (surface hardness, tensile breaking strength, tensile breaking elongation, 10%).
0% modulus, permanent elongation, compression set and gas permeability), stopper evaluation (liquid leakage resistance, coring performance and liquid leakage after needle puncture), and syringe gasket evaluation (foaming, pH, pH) Potassium manganate consumption and evaporation residue) were performed as described above. The results obtained are shown in Table 2 below.

COMPARATIVE EXAMPLE 2 Pellets of styrene-isobutylene-styrene triblock copolymer SIBS-2 were used alone for testability of moldability or for various physical property tests, films, plugs and syringes. Each gasket was manufactured by the method described above, and the moldability was evaluated and the molded product was evaluated (surface hardness, tensile breaking strength, tensile breaking elongation, 10%).
0% modulus, permanent elongation, compression set and gas permeability), stopper evaluation (liquid leakage resistance, coring performance and liquid leakage after needle puncture), and syringe gasket evaluation (foaming, pH, pH) Potassium manganate consumption and evaporation residue) were performed as described above. The results obtained are shown in Table 2 below.

Comparative Examples 3 and 4 Styrene-isobutylene-styrene triblock copolymers SIBS-1 and SIBS
Each pellet of BS-2 was dry-blended at a predetermined weight ratio shown in Table 2 below, and a cylinder temperature of 2 was obtained using a twin-screw extruder ("BT-30" manufactured by Plastics Industry Laboratory).
After melt-kneading at 30 ° C. and a screw rotation speed of 150 rpm, the mixture was pelletized to produce a pelletized block copolymer composition. Based on the gel permeation chromatograph of the obtained composition, the above [(ii)-
(I)] / (t) was determined. In this comparative example, SIBS-1 and SIBS-2 are considered to correspond to the block copolymers (I) and (II), respectively. Using the obtained composition, test pieces, films, plugs, and gaskets for syringes for moldability evaluation or various physical property tests were produced by the above-described methods, respectively. , Tensile strength at break, tensile elongation at break, 100% modulus, permanent elongation, compression set and gas permeability), stopper evaluation (liquid leakage resistance, coring performance and liquid leakage after needle puncture), and gasket evaluation for syringe (Bubbling property, △ pH, カ リ ウ ム potassium permanganate consumption, and amount of evaporation residue) were measured by the methods described above. Table 2 shows the obtained results.

Comparative Example 5 SIBS-2 and SIBS of styrene-isobutylene-styrene triblock copolymer
-3 are dry-blended at a predetermined weight ratio shown in Table 2 below, and the cylinder temperature is 230 using a twin-screw extruder ("BT-30" manufactured by Plastics Industry Laboratory).
The mixture was melt-kneaded at 150 ° C. and a screw rotation speed of 150 rpm, and then pelletized to produce a pelletized block copolymer composition. Based on the gel permeation chromatograph of the obtained composition, the above [(ii)-
(I)] / (t) was determined. In this comparative example, SIBS-3 and SIBS-2 are regarded as corresponding to the block copolymers (I) and (II), respectively. Using the obtained composition, test pieces, films, plugs, and gaskets for syringes for moldability evaluation or various physical property tests were produced by the above-described methods, respectively. , Tensile strength at break, tensile elongation at break, 100% modulus, permanent elongation, compression set and gas permeability), stopper evaluation (liquid leakage resistance, coring performance and liquid leakage after needle puncture), and gasket evaluation for syringe (Bubbling property, △ pH, カ リ ウ ム potassium permanganate consumption, and amount of evaporation residue) were measured by the methods described above. Table 2 shows the obtained results.

[0065]

[Table 2]

From the results shown in Table 1 above, the block copolymer compositions of the present invention of Examples 1 to 4 have excellent moldability, excellent flexibility, and mechanical properties represented by tensile breaking strength. It has excellent properties, low compression set and permanent elongation, excellent resilience (elastic recovery), good sealing, and low oxygen gas permeability and excellent gas barrier properties. Understand. Furthermore, the plugs manufactured using the block copolymer compositions of Examples 1 to 4 are extremely excellent in hermeticity without liquid leakage when plugged and liquid leakage after needle puncture, and the core Since the block copolymer composition is excellent in the ring property and is not separated from the stopper when pierced with a needle, it is understood that the block copolymer composition is extremely suitable as a stopper for a drug solution container accompanied by needle puncture. In addition, the syringe in which the gasket for a syringe manufactured using the block copolymer composition of Examples 1 to 4 was attached to the tip of the operation rod had good foaming resistance, pH, and potassium permanganate. Since both the consumption amount and the evaporation residue amount are extremely small, it can be seen that there are few elution portions from the gasket, and the safety and hygiene are excellent.

On the other hand, from the results shown in Table 2 above, Comparative Example 1 in which the styrene-isobutylene-styrene triblock copolymer having a relatively high molecular weight is used alone has a small compression set and a small permanent elongation, It can be seen that, although the recoverability is large and the sealing property is excellent, the melt viscosity is high and the molding processability is poor, and it is difficult to obtain a molded product having good surface properties. Relatively low molecular weight styrene-isobutylene-
In Comparative Example 2 using the styrene triblock copolymer alone, it can be seen that although the moldability was good, the compression set was large, the elastic recovery was small, and the sealing property was poor. Further, two types of styrene having different molecular weights are used.
Even in the case of the composition comprising the isobutylene-styrene triblock copolymer, the conditions based on the weight ratio of the high molecular weight component and the low molecular weight component or the conditions based on the gel permeation chromatograph as in Comparative Examples 3, 4 and 5 are used. When it is out of the range of the invention, it is understood that the balance between the physical properties of the rubber and the moldability is poor.

[0068]

Since the block copolymer composition of the present invention has good moldability, it can be easily prepared by using a molding method and a molding apparatus generally employed for thermoplastic polymers. For example, various molded articles having any shape and dimensions can be manufactured by melt molding by a molding method such as injection molding, extrusion molding, press molding, or blow molding.

The block copolymer composition of the present invention has a gas barrier property, compression set resistance, sealing property, sealing property, flexibility, mechanical properties, oil resistance, safety, hygiene and the like. It is extremely excellent in various properties, and can be effectively used for manufacturing not only general-purpose molded products but also sealing materials such as sealing materials, packing materials, gaskets, etc. by utilizing these characteristics. In particular, sealing materials for various instruments in the field of medicine and medicine manufactured using the block copolymer composition of the present invention (for example, stoppers for pharmaceutical containers, gaskets for syringes, sealing materials or packing materials for reduced-pressure blood collection tubes).
There is no liquid leakage at the time of sealing, liquid leakage after needle puncture, strip-shaped separation at the time of needle puncture, and furthermore, elution of components into the drug solution is extremely small, so sufficient safety and hygiene are ensured. It can be handled with good operability while securing. Furthermore, the block copolymer composition of the present invention utilizes the above-mentioned excellent properties to provide a food-related field (for example,
Sealing materials in processing equipment and containers for storing and storing food)
And other uses can be used safely and sanitarily.

Claims (4)

[Claims] 1. A block copolymer comprising an aromatic vinyl compound-based polymer block and an isobutylene-based polymer block and having a maximum molecular weight in a gel permeation chromatograph of 50,000 or more and 200,000 or less. A polymer comprising at least one kind of the polymer (I) and an aromatic vinyl compound-based polymer block and an isobutylene-based polymer block, and having a maximum molecular weight of 10,000 or more and less than 50,000 in a gel permeation chromatograph. A block copolymer composition obtained by mixing at least one kind of the block copolymer (II), wherein (2) the total content of the block copolymer (I) and the block copolymer (I) The ratio of the total content of (II) is 10/90 to 9 in the weight ratio of (I) / (II). 0/10 and (3) From the start of elution to the end of elution of the block copolymer (I) and the block copolymer (II) in the gel permeation chromatograph of the composition. , The maximum peak elution time (i) of the block copolymer (I) having the lowest molecular weight showing the maximum peak and the elution time of the block copolymer (II). The elution time of the maximum peak in the block copolymer having the highest peak and the highest molecular weight (i
A block copolymer composition whose difference from i) satisfies the condition represented by the following formula: [(ii)-(i)] / (t) ≧ 0.05. 2. The ratio of the weight average molecular weight Mw to the number average molecular weight Mn of the block copolymer (I) and the block copolymer (II) is 1.0 to 2 in terms of Mw / Mn. 2. The block copolymer composition according to claim 1, which is in the range of 0.0. 3. A molded article comprising the block copolymer composition according to claim 1. 4. A sealing material comprising the block copolymer composition according to claim 1.