JP2014094975A - Container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container excellent in squeeze property using a resin composition excellent in processability, flexibility, heat deposition property and non-adsorptive property of ingredients.SOLUTION: There is provided a container of which a resin layer directly contacting ingredients is formed by using a resin composition containing a polyester resin (A) of 66 to 89 wt.%, an olefin-based compatibilizer (B) of 1 to 14 wt.%, and a polyethylene-based resin (C) of 1 to 24 wt.%. The olefin-based compatibilizer (B) is preferably an ethylene-glycidyl methacrylate copolymer. The polyester resin (A) is preferably isophthalic acid-modified polyethylene terephthalate. A container shape is preferably a bottle shape or a tube shape.

Description

  The present invention relates to a container excellent in squeeze property using a resin composition excellent in processability, flexibility, heat-weldability, and non-adsorbability of contents.

Conventionally, in a bottle container or a tube container filled with a high-viscosity content, the container must be squeezed in order to squeeze the content from the container to the end. Therefore, the container needs to be squeezed. Therefore, containers are generally made using a relatively flexible resin such as polyethylene or polypropylene.
However, a container using polyethylene or polypropylene has no problem in squeeze property, but has a problem that many active ingredients such as drugs contained in the contents are adsorbed.

  Polyethylene terephthalate (PET) is generally used as a material that hardly adsorbs the active ingredients of the contents. However, in a container (single layer structure) using PET alone, the active ingredient is difficult to adsorb to the container, but since there is no squeeze property, when squeezing out high-viscosity contents, a crack enters the container and triggers it. There is a problem that the contents leak. Moreover, it is possible to give a container a certain amount of squeeze properties by using a multilayer material in which a flexible resin is laminated outside the PET layer. However, even in a multi-layer configuration, the PET layer still cracks while the container is crushed many times, and the contents leak as a result.

Moreover, in the container using PET as described above, for example, when container molding is performed by the direct blow molding method, the resin is low in viscosity, so that it is easy to draw down. Even if a container having a single layer structure or a multilayer structure can be formed, problems such as streak contamination due to PET draw-down and uneven thickness of the container due to uneven thickness also occur.
Even when a cylindrical sleeve is made by cutting a cylindrical tube-shaped resin melt-extruded in a single layer or multiple layers from a ring die to the required length when forming a tube container, there is a PET layer in the tube-shaped resin. In this case, streaks due to drawdown and thickness balance failure occur. Further, even if there is no problem in appearance, like a bottle container, since there is no squeeze property, cracking occurs due to crushing, and the contents leak from there.

In the conventional technology, in order to give impact resistance to the container, a mixture of polyethylene resin and glycidyl methacrylate copolymer is melted 2.5 to 10% by weight with respect to 90 to 97.5% by weight of polyethylene terephthalate. The container shape | molded using the resin composition formed by mixing is invented (refer patent document 1).
Further, a container molded using a resin composition in which 1 to 30 parts by weight of a resin having a glass transition temperature (Tg) of 0 ° C. or less is blended with 100 parts by weight of polyethylene terephthalate has been invented (Patent Document). 2).
These containers not only improve impact resistance, but also have some improvement in moldability in blow molding.

Japanese Patent Laid-Open No. 6-16826 Japanese Patent Laid-Open No. 7-188531

  Patent Document 1 describes a container having improved impact resistance, which is made of a resin composition in which polyethylene terephthalate, a polyethylene-based resin, and a glycidyl methacrylate copolymer are blended. The blending ratio of polyethylene terephthalate is 90%. Since it is as high as% by weight or more, the impact resistance is slightly improved, but the squeeze property is not improved much. Moreover, when this container is shape | molded by the direct blow molding method, since the mixture ratio of a polyethylene terephthalate is high, it is easy to draw down and cannot shape | mold a container stably. Further, since the container has a single layer structure, it is inferior in water vapor barrier property, oxygen barrier property and other gas barrier properties, and the contents are likely to deteriorate.

  Patent Document 2 describes a container having improved impact resistance, which is made of a resin composition in which polyethylene terephthalate and ethylene-glycidyl methacrylate copolymer are blended, but is mixed with ethylene-glycidyl methacrylate copolymer to be mixed. If the ratio is less than 10% by weight, the fluidity of the resin is hardly improved. For example, the direct blow molding method cannot be used. When the ratio of the ethylene-glycidyl methacrylate copolymer is 10% by weight or more, the fluidity is lowered and the impact resistance is improved. However, in the two-component mixed resin of polyethylene terephthalate and ethylene-glycidyl methacrylate copolymer, the crosslinking reaction ratio is Since it becomes high, heat weldability will become extremely low. As a result, the heat weldability of the bite portion at the bottom of the container at the time of direct blow molding is lowered, and the heat weldability of the sleeve and the mouth at the time of tube forming is extremely deteriorated. Moreover, since it is a container of a single layer structure like patent document 1, it is inferior to water vapor | steam barrier property, oxygen barrier property, and other gas barrier properties, and the content tends to deteriorate.

  In view of the above-described conventional drawbacks, the present invention provides a container having excellent squeeze characteristics using a resin composition excellent in processability, flexibility, heat-weldability, and non-adsorption of contents.

The container of this invention is a container which used the resin composition which consists of the following resin (A), resin (B), and resin (C) for the resin layer which contacts a content directly.
Resin (A): 66-89% by weight of polyester resin
Resin (B): 1-14% by weight of olefin compatibilizer
Resin (C): Polyethylene resin 1 to 24% by weight

The olefin compatibilizer (B) is preferably an ethylene-glycidyl methacrylate copolymer.
The polyester resin (A) is preferably isophthalic acid-modified polyethylene terephthalate.
The container shape is preferably a bottle shape or a tube shape.

  ADVANTAGE OF THE INVENTION According to this invention, the container excellent in squeeze property using the resin composition excellent in workability, a softness | flexibility, heat welding property, and the non-adsorption property of the contents can be provided.

Hereinafter, the present invention will be described based on preferred embodiments.
In the container of the present invention, the resin layer (innermost layer) that is in direct contact with the contents is polyester resin (A) 66 to 89% by weight, olefin compatibilizer (B) 1 to 14% by weight, polyethylene resin ( C) A container molded using a resin composition comprising a mixture of 1 to 24% by weight.

[Polyester resin (A)]
As the polyester resin (A) used in the innermost resin composition, a copolymer containing an acid component mainly composed of aromatic dicarboxylic acid and a diol component mainly composed of aliphatic diol (glycol) Is mentioned. In the copolymer, the acid component and the diol component are bonded via an ester bond. As the raw material for the acid component, a derivative capable of forming an ester such as a lower alkyl ester (for example, methyl ester) or an acid halide may be used.
Acid components include terephthalic acid, isophthalic acid, naphthalene-1,4-dicarboxylic acid, aromatic dicarboxylic acids such as naphthalene-2,6-dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and trimellit And tricarboxylic acids such as acids.
Examples of the diol component include ethylene glycol, neopentyl glycol, cyclohexane dimethanol, bisphenol compound or an ethylene oxide adduct thereof.

The polyester resin is preferably a polyethylene terephthalate resin, particularly a modified polyethylene terephthalate such as isophthalic acid-modified polyethylene terephthalate, from the viewpoints of moldability, heat resistance, mechanical strength, transparency, and availability.
The isophthalic acid modification rate in the isophthalic acid-modified polyethylene terephthalate (mole percentage occupied by the isophthalic acid component among the acid components) is preferably 2 to 50 mol%, and more preferably 4 to 26 mol%.

  The intrinsic viscosity (IV) of the polyester resin is preferably 0.60 to 0.85 dl / g. The intrinsic viscosity in the present invention is a value measured at 30 ° C. in a phenol / 1,1,2,2-tetrachloroethane (mass ratio 1/1) mixed solvent in accordance with JIS K 7367-5. When the intrinsic viscosity is less than 0.60 dl / g, the molecular weight of the resin is too low to obtain sufficient non-adsorption and barrier properties, and when the intrinsic viscosity exceeds 0.85 dl / g, Since the viscosity at the time of melting is too high, the molding process becomes difficult and the productivity is lowered.

[Olefin Compatibilizer (B)]
The olefin compatibilizer (B) used in the innermost resin composition has compatibility with the polyethylene resin (C) and is a hydroxyl group (—OH) or a terminal group of the polyester resin (A). It is a polymer having an epoxy group (> O) as a functional group capable of reacting with a carboxyl group (—COOH).
Examples of the olefin compatibilizer (B) include a copolymer containing at least an olefin (a) such as ethylene or propylene and a monomer (b) having an epoxy group such as glycidyl methacrylate (GMA). Other copolymerizable monomers include acrylic esters such as ethyl acrylate and butyl acrylate, and carboxylic acids such as acrylic acid and methacrylic acid.
Of these, an ethylene-glycidyl methacrylate copolymer comprising two components of ethylene and glycidyl methacrylate is preferable. In the ethylene-glycidyl methacrylate copolymer, the GMA content is preferably 2 to 30% by weight, more preferably 5 to 20% by weight.

[Polyethylene resin (C)]
The polyethylene resin (C) used for the resin composition of the innermost layer is blended in order to lower the melting point of the polyester resin (A) and improve the heat weldability. Examples of the polyethylene resin (C) include polyethylene (PE) homopolymer, linear low density polyethylene (C4-LLDPE) obtained by copolymerizing ethylene and α-olefin (1-butene, etc.) having 4 carbon atoms. Linear low density polyethylene (C6-LLDPE) obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms (1-hexene, etc.), and α-olefin having 1 to 8 carbon atoms (1-octene). Linear low density polyethylene (C8-LLDPE), ethylene-vinyl acetate copolymer (EVA) and the like.
As the polyethylene resin, polyethylene, particularly linear low density polyethylene (LLDPE) is desirable. Polyethylene is preferred having a density of 0.890~0.930g / cm ^3, density is more preferably polyethylene 0.910~0.925g / cm ^3.

[Innermost layer resin composition]
The innermost resin composition used in the present invention is mainly composed of a polyester resin (A), an olefin compatibilizer (B), and a polyethylene resin (C).
The compounding ratio of the resin composition is 66 to 89% by weight of the polyester resin (A), 1 to 14% by weight of the olefin compatibilizer (B), and 1 to 24% by weight of the polyethylene resin (C). Preferably there is.
An appropriate additive can be added to the resin composition as long as the object of the present invention is not impaired. Examples of the additive include an antioxidant, a lubricant, an anti-blocking agent, a flame retardant, an ultraviolet absorber, a light stabilizer, an antistatic agent, and a colorant.
The thickness of the innermost layer is preferably selected from the viewpoints of processability, flexibility, non-adsorption property, and the like, and is preferably 20 to 200 μm, for example.

[container]
The container of the present invention may have a single-layer configuration using only the innermost resin composition, but preferably has a multilayer configuration to ensure water vapor barrier properties and gas barrier properties. In the case of a multilayer molded container, each of the layers may be made of resin, and one or more layers of different materials such as paper and aluminum foil may be laminated. As for the thickness of the trunk | drum of a container, 300-1500 micrometers is preferable. The container shape is preferably a bottle shape or a tube shape.

  In layers other than the innermost layer of the container, that is, the outermost layer, the intermediate layer, and the like, one type or two or more types of resin layers such as other types of thermoplastic resins and adhesive resins can be provided. In order to prevent intrusion of moisture and gas, a water vapor barrier resin or a gas barrier resin is preferable. Examples of the water vapor barrier resin include polyolefin resins such as polyethylene and polypropylene. Examples of the gas barrier resin include polyamide resins such as nylon, ethylene-vinyl alcohol copolymer (EVOH), and the like. Examples of the adhesive resin include acid-modified polyolefins such as acid-modified polyethylene and acid-modified polypropylene.

The container of the present invention can also be produced as an integrally molded container having a bottom part and a mouth part by hollow molding such as blow molding, which is obtained by heating and melting and extruding. This method can be used when the container shape is a bottle shape or a tube shape. Examples of the blow molding method include a direct blow molding method and an injection blow molding method.
In the case of a tube shape, it can also be manufactured by forming a body portion of a predetermined length with a cylindrical sleeve and thermally welding it with a separate molded product constituting a shoulder portion or a mouth portion. The cylindrical sleeve may be formed into a tube shape by extrusion molding, or may be formed into a sheet shape by extrusion molding, and the back portion may be thermally welded in the vertical direction to form a cylinder shape.

  In the manufacturing process of the multilayer molded container, the resin of each layer can be extruded in multiple layers and molded by blow molding, extrusion molding or the like. All the resin layers used in the multilayer molding container may be extruded at the same time to mold the multilayer in a lump. In the case of manufacturing a laminated tube, a resin tube having one or more layers including the innermost layer is formed first, and then a different material such as paper or aluminum foil or the outermost layer is left on the resin tube. These layers can also be laminated.

  In particular, the container of the present invention can be suitably used for packaging content products containing perfumes and active ingredients such as foods and drinks, cosmetics, and drugs.

Hereinafter, the present invention will be specifically described with reference to examples.
[Preparation of resin composition sample]
Resins were melt-kneaded according to the composition shown in Table 1 (unit:% by weight) to prepare melt-kneaded pellets of the resin compositions of Examples and Comparative Examples. Subsequently, the pellets were formed to a thickness of 1 mm with a hot press to obtain a single-layer press sheet sample.

In addition, the meaning of the abbreviation used in Table 1 is as follows.
“PET (1)”: isophthalic acid modified PET (isophthalic acid modified rate: 12 mol%, IV = 0.80 dl / g, ρ = 1.34 g / cm ³ , Tm = 224 ° C.)
“PET (2)”: isophthalic acid modified PET (isophthalic acid modified rate 5 mol%, IV = 0.80 dl / g, ρ = 1.34 g / cm ³ , Tm = 240 ° C.)
“PET (3)” PET-G GN071 (IV = 0.75 dl / g, ρ = 1.27 g / cm ³ , manufactured by Eastman Chemical Co.)
“PET (4)” KRAPET (registered trademark) KS710B-8S (terephthalic acid-ethylene glycol-bisphenol A ethylene oxide addition polymer condensate, IV = 1.20 dl / g, ρ = 1.38 g / cm ³ , Tm = 233 ° C., manufactured by Kuraray Co., Ltd.)
“E-GMA (1)”: ethylene-glycidyl methacrylate copolymer (Tm = 105 ° C., MFR = 3 g / 10 min, GMA 6% by weight)
“E-GMA (2)” ethylene-glycidyl methacrylate copolymer (Tm = 103 ° C., MFR = 3 g / 10 min, GMA 12 wt%)
“PE (1)” — Octene-1 copolymerized LLDPE (Tm = 119 ° C., MFR = 1.3 g / 10 min, ρ = 0.919 g / cm ³ )
Here, IV means intrinsic viscosity, ρ means density, Tm means melting point, and MFR means melt flow rate.

[Evaluation method]
(1) Melt flow rate (MFR) measurement The melt flow rate (MFR) of the resin composition was measured at a temperature of 220 ° C, 240 ° C or 260 ° C and a value (g / 10 min) at a load of 2.16 kg. MFR was evaluated as an index of drawdown in direct blow molding and moldability of tube extrusion.
(2) Bending test A press sheet molded to a thickness of 1 mm was cut into a size of 15 mm width x 100 mm length, and 1.5 kgf, using an MIT folding resistance tester (manufactured by Tester Sangyo Co., Ltd.) A bending test was carried out at an angle of 135 °, and the number of bendings until breaking occurred was measured. The number of bendings was evaluated as an index of the squeeze property of the container.
(3) Tocopherol acetate residual ratio A press sheet molded to a thickness of 1 mm was cut into a size of 7 mm width x 30 mm height to prepare a test piece. In addition, 3 ml of a commercial lotion containing α-tocopherol acetate (vitamin E acetate) as an active ingredient is placed in a light-shielding glass bottle having an outer diameter of 15 mm and a height of 32 mm, and the test piece is placed therein, and the lid is closed and sealed. After being stored at 40 ° C. for 1 month, it was opened, and the residual amount of α-tocopherol acetate in the lotion was quantified by high performance liquid chromatography, and the residual ratio of the active ingredient was calculated based on the residual amount. In addition, the amount of the lotion put in the glass bottle is an amount sufficient for the entire test piece having a height of 30 mm to be immersed in the lotion.

  Table 2 shows the evaluation results of (1) to (3).

(4) Evaluation of moldability and squeeze property With the configuration shown in Table 3, a container was prepared by direct blow molding, and the moldability and squeeze property were evaluated. For the innermost layer of the container, the resin composition of either Example or Comparative Example (see Tables 1 and 2) was used. The tube container has a five-layer structure of innermost layer / adhesive resin / EVOH layer / adhesive resin / outermost layer, and the bottle container has a three-layer structure of innermost layer / adhesive resin / outermost layer. The thickness of each layer (target value after blow molding) was set to 50 μm for the innermost layer, 700 μm for the outermost layer, 50 μm for the adhesive resin, and 150 μm for the EVOH layer (in the case of five layers).
The extrusion temperature of each layer is also shown in “Configuration” of Table 3, but the innermost resin is different in density, melting point, and MFR, so it cannot be extruded at the same set temperature, and set to the lowest extrudable temperature.

In the evaluation of formability, “○” indicates that the container was successfully formed, “△” indicates that the container was formed but streaks were mixed due to drawdown, and thickness unevenness occurred. Those that could not be molded due to the collapse of the mark are indicated by “x”.
In the evaluation of the squeeze property, “◯” indicates that a container that has been squeezed several times returns to its original shape, “x” indicates that it is difficult to squeeze, and a crack is mixed only by squeezing once.

In addition, the meaning of the abbreviation used in Table 3 is as follows.
“EVOH”: ethylene-vinyl alcohol copolymer (ethylene ratio: 32 mol%, Tm = 183 ° C., MFR = 3.8 g / 10 min, ρ = 1.19 g / cm ³ )
“Adhesive resin”: maleic anhydride-modified polyethylene (Tm = 80 ° C., MFR = 7.2 g / 10 min, ρ = 0.89 g / cm ³ , ethylene-based plastomer base)
"PE (2)" ... HB235R (high density polyethylene, manufactured by Nippon Polyethylene Co., Ltd.)

(5) Evaluation results Table 2 shows the evaluation results of the resin composition and the single press sheet.
From the results of Table 2, according to the present invention (resin compositions of Examples 1 to 7), PET, E-GMA, and PE were mixed in a predetermined blending region, so that PET alone (Comparative Examples 6 and 7) The fluidity was lower than that, and the number of foldings exceeded 5,000 in the folding test. This is an index indicating improvement in moldability and squeeze property when the container is molded. Also in the tocopherol acetate adsorption test, a residual rate equivalent to that of PET alone (Comparative Examples 6 to 9) is shown.
Comparative Examples 1-5 are evaluated as having low moldability from the MFR value of the resin composition.
When the blending ratio of PET is low (Comparative Example 5), the number of folds is improved, but the MFR at 260 ° C. is less than 0.2 and the fluidity is extremely low, so extrusion molding during direct blow molding or injection blow Injection (injection) molding in molding is not possible.
When E-GMA is not included (Comparative Example 1), the number of bendings is greatly reduced.
When 90% by weight of PET is contained (Comparative Examples 2 to 4), the MFR is almost the same as that of the PET alone (Comparative Example 6), so that the moldability is not improved, and the number of bending does not exceed 5,000 times, so that The properties are also lower than in the present invention.

Table 3 shows the results of moldability. In the case of a PET resin having a high melting point or density (Comparative Examples 7 and 9), the innermost layer resin must be extruded at a very high temperature of 260 ° C., When multilayered, the adhesive resin extruded at 190 ° C. and EVOH extruded at 210 ° C. cannot be balanced and multilayered.
By setting it as the resin mixture (Examples 2 and 7) of this invention, extrusion temperature can be lowered | hung rather than PET single-piece | unit (comparative example 7), As a result, multilayer shaping | molding is attained.
Further, the MFR of the resin composition shown in Table 2 and the moldability of the container shown in Table 3, and the number of bendings shown in Table 2 and the squeeze property shown in Table 3 are correlated.

Claims (4)

  The resin layer in direct contact with the contents is a mixture of 66 to 89% by weight of polyester resin (A), 1 to 14% by weight of olefin compatibilizer (B), and 1 to 24% by weight of polyethylene resin (C). The container shape | molded using the resin composition which becomes.   The container according to claim 1, wherein the olefin-based compatibilizer (B) is an ethylene-glycidyl methacrylate copolymer.   The container according to claim 1 or 2, wherein the polyester resin (A) is isophthalic acid-modified polyethylene terephthalate.   The container according to claim 1, wherein the container shape is a bottle shape or a tube shape.