JP2017030765A - Multilayer container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable multilayer container having performance required for a vial such as transparency, gas barrier property, chemical adsorption resistance, and steam sterilization resistance, and having excellent adhesion performance. A multilayer container having at least a layer containing a cyclic polyolefin resin and a layer containing an ethylene-vinyl alcohol copolymer. The layer containing the cyclic polyolefin resin and the layer containing the ethylene-vinyl alcohol copolymer are bonded by an adhesive layer interposed therebetween. The adhesive layer includes a cyclic polyolefin resin obtained by graft polymerization of maleic anhydride and an antioxidant. The glass transition point of the cyclic polyolefin resin of the adhesive layer is preferably 130 ° C. or higher. [Selection] Figure 1

Description

  The present invention relates to a multilayer container filled with, for example, various chemicals, and more particularly to an improvement of an adhesive layer that bonds a layer containing a cyclic polyolefin resin and a layer containing an ethylene-vinyl alcohol copolymer. .

  As medical containers filled with various chemical solutions, for example, blow-molded bottles or blow-molded bags made of plastic are used. Blow molding makes it possible to efficiently produce containers, and in recent years, medical containers called vials have also been produced by blow molding technology.

  However, in the medical container, the requirements regarding performance such as chemical resistance, chemical adsorption resistance, gas barrier property, steam sterilization resistance, etc. are stricter than general containers. Mechanical strength is also required. In order to meet these requirements, so-called multilayer vials have been proposed, and various studies have been made on plastic materials and layer structures used for each layer.

  For example, in terms of materials, from the viewpoint of drug adsorption, etc., it has been studied to use a cyclic polyolefin-based resin instead of polypropylene or the like (see Patent Document 1). Patent Document 1 discloses a sanitary ware container (container for storing pharmaceuticals, foods and other sanitary wares) made of a material containing a resin containing a cyclic olefin compound or a crosslinked polycyclic hydrocarbon compound as a polymer component. ) Is disclosed, and it is said that it is possible to provide a highly hygienic container that can stably maintain the quality of the contents for a long period of time and can pass the tests stipulated in various official documents.

  On the other hand, with respect to gas barrier properties, use of an ethylene-vinyl alcohol copolymer (EVOH) has been studied. For example, Patent Document 2 discloses a plastic product having an ethylene-vinyl alcohol copolymer (EVOH) as an intermediate layer. A vial is disclosed.

Japanese Patent Laid-Open No. 5-293159 JP 2013-74928 A

  By the way, in the aforementioned multilayer vial, not only the performance of each layer but also the performance of the adhesive layer is important. For example, the cyclic polyolefin-based resin is difficult to bond and there is a problem that it is difficult to select an adhesive. Considering the functions required of the vial, it is considered desirable to produce a vial with a multilayer structure in which a layer containing a cyclic polyolefin resin and a layer containing an ethylene-vinyl alcohol copolymer are combined. It is desired that the adhesive layer interposed between the layer containing the resin and the layer containing the ethylene-vinyl alcohol copolymer exhibit a sufficient adhesive force to both.

  However, for example, a polypropylene-based adhesive has excellent transparency and a high melting point, but lacks adhesive strength with respect to a cyclic polyolefin-based resin. Polyethylene adhesive with hydrogenated styrene-based thermoplastic elastomer (SEBS) must have a melting point of 100 ° C or lower in order to ensure transparency, and may be dissolved during autoclave sterilization or pre-dried In this case, there is a problem that the strain is relaxed and bubbles are generated. In addition, since the molding temperature is greatly different from that of the cyclic polyolefin resin, there is a problem that it cannot be stably molded by drawdown or the like.

  The present invention has been proposed in view of the above-described conventional situation, and has performances required for a vial, such as transparency, gas barrier properties, chemical adsorption resistance, and steam sterilization resistance, and excellent adhesive performance. An object of the present invention is to provide a highly reliable multilayer container having

  In order to achieve the above object, a multilayer container of the present invention is a multilayer container having at least a layer containing a cyclic polyolefin resin and a layer containing an ethylene-vinyl alcohol copolymer, wherein the cyclic polyolefin resin The layer containing ethylene and the layer containing ethylene-vinyl alcohol copolymer are adhered by an adhesive layer interposed therebetween, and the adhesive layer contains a cyclic polyolefin resin obtained by graft polymerization of maleic anhydride and an antioxidant. Characterized by

  In order to ensure adhesion to the cyclic polyolefin resin, it is effective to use the cyclic polyolefin resin as the adhesive. Furthermore, if maleic anhydride is introduced into the cyclic polyolefin resin used in the adhesive layer, It is considered that the adhesion to ethylene-vinyl alcohol copolymer (EVOH) is also improved by the reaction.

  However, even when such an adhesive is used, it has been found that, for example, it is not possible to cope with modification due to resin degradation (nonpolar material becomes polar), and a phenomenon occurs in which the adhesive strength is reduced. It was. In particular, the cyclic polyolefin-based resin tends to undergo oxidative degradation due to heat applied during molding, and the surface hydrophobicity tends to decrease and adhesive strength tends to decrease.

  The present inventors have made various studies in order to eliminate such a decrease in adhesive force. As a result, the inventors have found that the addition of an antioxidant improves the adhesive strength and suppresses a decrease in the adhesive strength due to resin degradation. Although details are not clear about the reason, it is presumed that the polarity change of the resin can be suppressed and the hydrophobicity can be maintained.

  According to the present invention, it is possible to provide a highly reliable multi-layer container having performances required for a vial such as transparency, gas barrier properties, chemical adsorption resistance, and steam sterilization resistance, and having excellent adhesion performance. Is possible.

It is a figure which shows the multilayer container concerning embodiment of this invention, (a) is a partially broken side view, (b) is a schematic sectional drawing which expands and shows a layer structure.

  Hereinafter, an embodiment of a multilayer container to which the present invention is applied will be described in detail with reference to the drawings.

  First, the layer configuration of the multilayer container will be described. For example, as shown in FIG. 1A, the multilayer container 1 is formed by forming a neck portion 3 on an upper portion of a container body (body portion) 2, and an upper end opening 4 of the neck portion 3 has, for example, When used as a vial, a lid such as a rubber stopper is attached. The multilayer container 1 is formed by, for example, blow molding, and in this example, the container body 2 has a perfect circle shape. Of course, the shape is arbitrary, and various shapes can be used depending on the application. In addition, although the multilayer container 1 of this embodiment assumes the use as a medical container and is steam-sterilized in any process, of course, it is not restricted to this.

  The multi-layer container 1 has a multi-layer structure. In this example, as shown in FIG. 1B, three layers of an inner layer 5, a barrier layer 6, and an outer layer 7 are laminated and bonded between the layers. Adhesive layers 8 and 9 are provided for a total of five layers. The layer configuration is not limited to this, and may be a configuration in which more layers are stacked, or a stacked configuration with a smaller number of layers.

  Although the material of each layer is arbitrary, for example, in the laminated structure, the inner layer 5 is formed of a cyclic polyolefin resin. The cyclic polyolefin resin has a low drug adsorptivity, and by using the cyclic polyolefin resin for the inner layer 5, the adsorption of the drug contained in the chemical solution filled in the multilayer container 1 can be minimized. In addition, since the cyclic polyolefin-based resin is highly transparent, if it is used for the inner layer 5 and the outer layer 7, the transparency of the entire multilayer container 1 can be ensured.

  The cyclic polyolefin resin used for the inner layer 5 is a resin having at least a polymerizable cyclic olefin having an ethylenic double bond in the ring as a polymerization component, and the cyclic olefin as a polymerization component is a monocyclic olefin. It may be a polycyclic olefin.

  Any known olefin can be used as the cyclic olefin, but typical ones are norbornene, cyclopentadiene, dicyclopentadiene, and further obtained by condensation of norbornene and cyclopentadiene. A polycyclic olefin etc. can be illustrated.

  The cyclic polyolefin-based resin may be a homopolymer of one type of cyclic olefin, or a copolymer of different types of cyclic polyolefin (for example, a copolymer of a monocyclic olefin and a polycyclic olefin). And the like. Alternatively, it may be a copolymer of a cyclic olefin and another copolymerizable monomer. In this case, examples of other copolymerizable monomers include chain olefins such as ethylene and propylene, (meth) acrylic monomers, unsaturated dicarboxylic acids or derivatives thereof, polymerizable nitrile compounds, and vinyl esters. And conjugated dienes.

  However, with respect to the cyclic polyolefin resin of the inner layer 5, from the viewpoint of low drug adsorption, it consists only of a cyclic polyolefin such as a homopolymer of one type of cyclic olefin or a copolymer of different types of cyclic polyolefin. A homopolymer is preferred. Cyclic polyolefin homopolymers have a lower drug adsorption than copolymers with other copolymerizable monomers. Moreover, it is preferable also in providing favorable impact resistance.

  As with the inner layer 5, the outer layer 7 may be a cyclic polyolefin-based resin or other resin. By using a cyclic polyolefin resin for the outer layer 7 as well, the transparency of the entire multilayer container 1 can be ensured. Examples of other resins used for the outer layer 7 include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, and polyamide resins such as nylon as trade name.

  On the other hand, the barrier layer 6 is formed of a resin having a high gas barrier property. Examples of the gas barrier resin include an ethylene-vinyl alcohol copolymer resin, a polyamide resin, and a saturated polyester resin. Among them, an ethylene-vinyl alcohol copolymer resin is preferably used. The ethylene-vinyl alcohol copolymer resin is a saponified ethylene-vinyl acetate copolymer, and any known one can be used. In the ethylene-vinyl alcohol copolymer resin, the ethylene content is preferably 20 to 70 mol% and the saponification degree of vinyl acetate is 95 mol% or more, more preferably the ethylene content is 25 to 50 mol%, and acetic acid. The saponification degree of vinyl is 98 mol% or more. If the degree of saponification is low, the gas barrier property may be lowered.

  The ethylene-vinyl acetate copolymer resin may include a third monomer component that can be copolymerized with the ethylene or the like. Examples of the third monomer component that can be copolymerized include α-olefins such as propylene, and unsaturated acids such as acrylic acid and methacrylic acid. The proportion of these copolymerization monomers is preferably 5 mol% or less.

  Next, an adhesive used for bonding the inner layer 5 and the barrier layer 6 or the barrier layer 6 and the outer layer 7 (that is, an adhesive constituting the adhesive layers 8 and 9), which includes a layer containing a cyclic polyolefin resin, An adhesive layer (for example, an adhesive layer 8 between an inner layer 5 formed of a cyclic polyolefin resin and a barrier layer 6 formed of an ethylene-vinyl alcohol copolymer) interposed between layers containing an ethylene-vinyl alcohol copolymer. ) Is preferably an adhesive mainly composed of maleic anhydride-modified cyclic polyolefin. Maleic anhydride-modified cyclic polyolefin is obtained by graft polymerization of maleic anhydride to cyclic polyolefin, and since it is the same kind of resin material, it has good affinity for the cyclic polyolefin resin of inner layer 5 and has sufficient adhesion. Demonstrate power. Moreover, since maleic anhydride is introduced, the adhesive force to the ethylene-vinyl alcohol copolymer (EVOH) is also ensured by a chemical reaction.

  In the maleic anhydride-modified cyclic polyolefin, as the cyclic polyolefin for graft polymerization of maleic anhydride, the same cyclic polyolefin as used for the inner layer 5 can be used, but its glass transition point (Tg) is 130 ° C. or higher. Preferably there is. If the glass transition point is less than 130 ° C, the heat resistance may be insufficient. The maleic anhydride conversion rate in the maleic anhydride-modified cyclic polyolefin is preferably 0.5 to 1.5%.

  In addition to the maleic anhydride-modified cyclic polyolefin, an antioxidant is added to the adhesive layer 8. By adding an antioxidant, it is possible to effectively suppress a decrease in adhesive force caused by denaturation due to resin degradation. Moreover, generation | occurrence | production of the carbide | carbonized_material can also be suppressed.

  Examples of the antioxidant include phosphorus antioxidants and phenolic antioxidants, and these can be used alone or in combination. Any known phosphoric antioxidant or phenolic antioxidant may be used. For example, phosphorus antioxidants include high molecular weight phosphorus antioxidants and low molecular weight phosphorus antioxidants, any of which may be used.

  Specific examples of the high molecular weight phosphorus antioxidant include tris (2,4-branched C3-8 alkyl-butylphenyl) phosphite [tris (2,4-di-t-butylphenyl) phosphite]. Etc.] and tetrakis (2,4-di-branched C3-8 alkylphenyl) -4,4'-C2 such as tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene phosphite -4 alkylene phosphite. Examples of commercially available products include “Irgafos 168” manufactured by Ciba Japan.

  Examples of low molecular weight phosphorus antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite; tri-2,4-dimethylphenylphosphine, tri-2,4, List phosphine compounds such as 6-trimethylphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tri-o-anisylphosphine, tri-p-anisylphosphine, etc. Can do.

  As for the phenolic antioxidant, there are a high molecular weight phenolic antioxidant and a low molecular weight phenolic antioxidant, either of which may be used.

  Examples of the high molecular weight phenolic antioxidant include hindered phenolic compounds. Examples of the hindered phenol compound include tris (2-alkyl-4-hydroxy-5-branched C3) such as 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane. Tris (3,5-di-branched) such as -8 alkylphenyl) butane and 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene 1,3 such as C3-8 alkyl-4-hydroxybenzyl) benzene, 1,3,5-trimethyl-2,4,6, -tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene , 5-trialkyl-2,4,6-tris (3,5-di-branched C3-8alkyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3,5-di-t-butyl- 4-hi Roxyphenyl) propionate] tetrakis [alkylene-3- (3,5-di-branched C3-8 alkyl-4-hydroxyphenyl) propionate] C1-4 alkane, pentaerythrityltetrakis [3- (3,5 Pentaerythrityltetrakis [3- (3,5-di-branched C3-8 alkyl-4-hydroxyphenyl) propionate] such as -di-t-butyl-4-hydroxyphenyl) propionate]. Examples of commercially available products include “Irganox 1010” manufactured by Ciba Japan.

  Low molecular weight phenolic antioxidants include dibutylhydroxytoluene (BHT), butylated hydroxyanisole (BHA), 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4 -Ethylphenol, 2,6-di-t-butylphenol, 2,4-dimethyl-6-t-butylphenol, 2-methyl-4,6-di-nonylphenol, butylhydroxyanisole, styrenated phenol, 2,4, Monophenol compounds such as 6-tri-t-butylphenol and 4,4'-dihydroxydiphenyl, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl) -6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol) 4,4′-butylidenebis (2,6-di-t-butylphenol), 1,1′-bis (4-hydroxyphenyl) cyclohexane, 2,2′-dihydroxy-3,3′-di (α-methylcyclohexyl) ) Bisphenol compounds such as 5,5′-dimethyldiphenylmethane, hydroquinone compounds such as 2,5-di-t-butylhydroquinone, hydroquinone monomethyl ether, 2,5-di- (tertiary amyl) hydroquinone, n- Examples include hindered phenol compounds such as octadecyl-3- (4′-hydroxy-3 ′, 5′-di-t-butylphenol) propionate. Moreover, the low molecular weight phenolic antioxidant includes a hydrazine compound having a hindered phenol structure {N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine } And the like are also included.

  Although the addition amount of the antioxidant is arbitrary, it is preferably, for example, 300 ppm to 3000 ppm.

  Regarding the adhesive layer 9 between the outer layer 7 and the barrier layer 6, as in the case of the inner layer 5, in the case where the outer layer 7 contains a cyclic polyolefin type, like the adhesive layer 8, an antioxidant is added to the maleic anhydride-modified cyclic polyolefin. It is preferable to use a material to which is added.

  When the outer layer 7 does not contain a cyclic polyolefin-based resin, the adhesive layer 9 does not necessarily have to be obtained by adding an antioxidant to the maleic anhydride-modified cyclic polyolefin. For example, maleic anhydride-modified polypropylene or maleic anhydride polyethylene can be used as an adhesive. In this case, the antioxidant may not be added. Moreover, you may add a styrene-type elastomer etc.

  For example, when a styrene-based elastomer is added to maleic anhydride-modified polypropylene, the melting point becomes high, and the adhesive layer does not become cloudy even if steam sterilization is performed. In addition, the styrene-based elastomer plays a role of absorbing shock, and even if a large impact is applied, the interface peeling does not occur.

  The styrene elastomer to be added is composed of a thermoplastic styrene end block and an elastic intermediate block, and is composed of a copolymer of a styrene monomer and an elastomer component. Here, examples of the styrene monomer include styrene and α-methylstyrene, and examples of the elastomer component include butadiene, isoprene, chloroprene, and 1,3-pentadiene. Specific examples of the styrene elastomer include styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isoprene-butadiene copolymer, and the like. Also. The styrenic elastomer used may be modified with maleic anhydride.

  The above is the configuration of the multilayer container 1, but the thickness of each layer in the multilayer container 1 is also arbitrary. For example, the inner layer 5 is 200 μm to 500 μm, the barrier layer 6 is 10 μm to 70 μm, the outer layer 7 is 200 μm to 500 μm, and the adhesive layers 8 and 9 are 5 μm to 50 μm, respectively.

  In the multilayer container 1 having the above-described multilayer structure, the inner layer 5 is formed of a low-adsorbent cyclic polyolefin resin, so that the adsorption of the drug can be suppressed, and the inner layer 5 and the outer layer 7 are formed of the cyclic polyolefin. If it forms with a system resin, a highly transparent medical container is realizable. Moreover, since it is set as the layer structure which laminated | stacked the barrier layer 6 which consists of ethylene-vinyl alcohol copolymer resin etc. on these, it is possible to fully ensure gas-barrier property.

  In addition, since maleic anhydride-modified cyclic polyolefin is used for the adhesive layer interposed between the layer containing the cyclic polyolefin-based resin and the layer containing the ethylene-vinyl alcohol copolymer, and an antioxidant is added, Generation | occurrence | production can be suppressed and the fall of the adhesive force which arises by modification | denaturation by resin degradation, etc. can be suppressed effectively.

  Although the embodiment to which the present invention is applied has been described above, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications or improvements are made without departing from the gist of the present invention. It is possible.

  Hereinafter, specific examples of the present invention will be described based on experimental results.

Preparation of multilayer containers Multilayer containers 1 to 8 having the layer structure shown in Table 1 were prepared. The produced multilayer container has a so-called vial shape, the internal volume is 5 to 100 mL, and the average thickness of the entire container is 1 mm. In the layer configuration, the materials used (each material in the table) are as follows.
・ COP1: Cyclic polyolefin Nippon Zeon, trade name ZEONEX 690R (Tg 145 ° C)
COP2: Cyclic polyolefin Nippon Zeon, trade name ZEONEX 1020R (Tg 102 ° C.)
EVOH: Nihon Gosei Co., Ltd., trade name DC3203B
Antioxidant: Ciba Japan, trade name Irganox 1010 + Ciba Japan, trade name Irgafos 168 (1: 3)
-Maleic anhydride grafted PE: manufactured by Mitsubishi Chemical Corporation, trade name L522
Maleic anhydride graft PP + SEBS: Mitsubishi Chemical Corporation, trade name MC721AP

Evaluation The produced multilayer container was evaluated for the carbide generation ratio, adhesive strength, transparency, and heat resistance. The evaluation results are also shown in Table 1. The evaluation method for each evaluation item is as follows.
· Carbide occurrence rate: the rate of 0.2 mm ² or more carbide contained in produced continuously at least 6 hours was measured, the case where three or less ○, a case where the 4-10 △, 11 pieces The case where it was above was set as x.
-Adhesive strength: When a force that destroys the container was applied, the case where the layer was not peeled was rated as x when the layer was peeled off.
・ Transparency: Measure the transparency (light transmittance at λ = 450 nm) of the part with a thickness of 1 mm, ○ if it is 70% or more, Δ if it is 55% to 69%, 54% or less The case where it is is set as x.
・ Heat resistance: Inject the internal volume according to the intended use of the vial, and then crimp the rubber stopper with aluminum (plastically join the vial and the aluminum lid. The parts fit together and have ductility. The parts of the material were plastically deformed and joined.), And the steam sterilization temperature at which treatment was possible for 30 minutes without deformation of the container was measured. The case of 121 ° C. to 125 ° C. was marked with ◎, the case of 116 ° C. to 120 ° C. with ◯, the case of 111 ° C. to 115 ° C. with Δ, and the case of 110 ° C. or less with x.

  When cyclic polyolefin is used for the inner and outer layers, the adhesive strength can be maintained by using a cyclic polyolefin-based adhesive. However, if antioxidants are not added, it can cope with the generation of carbides and modification due to resin deterioration. It cannot be done and the adhesive strength is reduced (multilayer containers 3 and 4).

  In the multilayer container 6 using maleic anhydride-modified polyethylene as the adhesive, not only the generation of carbides but also the heat resistance is insufficient unless an antioxidant is added. Even if an antioxidant is added, the lack of heat resistance cannot be resolved (multilayer container 7).

  The multilayer container 8 using maleic anhydride-modified polypropylene + SEBS as an adhesive has a problem that the adhesive force is insufficient and the practical sterilization temperature is lowered. In the multilayer container 2 whose outer layer is heat-resistant polyethylene terephthalate (heat-resistant PET), the effect of the strong adhesion type maleic anhydride-modified polypropylene + SEBS is exhibited, and the performance is maintained.

DESCRIPTION OF SYMBOLS 1 Multilayer container 2 Container body 3 Neck part 4 Opening part 5 Inner layer 6 Barrier layer 7 Outer layer 8,9 Adhesive layer

Claims (3)

A multilayer container having at least a layer containing a cyclic polyolefin-based resin and a layer containing an ethylene-vinyl alcohol copolymer,
The layer containing the cyclic polyolefin-based resin and the layer containing the ethylene-vinyl alcohol copolymer are bonded by an adhesive layer interposed therebetween,
The multi-layer container, wherein the adhesive layer contains a cyclic polyolefin resin obtained by graft polymerization of maleic anhydride and an antioxidant.   An outer layer, an adhesive layer, a barrier layer, an adhesive layer, and an inner layer are laminated in order from the outside, the barrier layer is a layer containing an ethylene-vinyl alcohol copolymer, and the inner layer is a layer containing a cyclic polyolefin resin. 2. The multilayer container according to claim 1, wherein the adhesive layer between the barrier layer and the inner layer contains a cyclic polyolefin resin obtained by graft polymerization of maleic anhydride and an antioxidant.   The multilayer container according to claim 1 or 2, wherein a glass transition point of the cyclic polyolefin resin of the adhesive layer is 130 ° C or higher.

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