JP2016160399A - Thermoplastic resin composition, lid material for easily opening container, and easily opening container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition capable of forming a seal layer sufficiently high in heat seal strength and excellent in easily opening property and peeling appearance with good moldability and suitable as a sealant material.SOLUTION: There is provided a thermoplastic resin composition containing following (A) to (C) components. (A) component: polyester having melting peak temperature of 110 to 150°C. (B) component: styrenic thermoplastic elastomer having the styrene content of less than 25 wt.%. (C) component: amorphous polyester and/or polyolefin.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic resin composition capable of forming a sealing layer having a sufficiently high heat seal strength and excellent in easy-openability, transparency, etc. with good moldability. The present invention also relates to a lid for an easy-open container and an easy-open container having a seal layer formed from the thermoplastic resin composition.

  Conventionally, as a packaging method for foods, beverages, medicines, cosmetics, medical instruments, etc., an article to be packaged is put in a container body molded in a tray shape or a cup shape with a resin such as a polyester resin or a polycarbonate resin, A method in which a lid is brought into contact with the opening and sealed by heat sealing is widely used. In this type of package, there is no leakage of the package from the container, and it is necessary to peel off the lid when removing the package. It is necessary to have a heat seal strength that is as high as possible, that is, to be easily openable.

  Generally, there are mainly two types of sealants (sealing materials) used for easy-opening lid materials: delamination type and cohesive peeling type. The delamination-type lid material is composed of a seal layer, a holding layer, and a base material, and the seal layer is formed of the same kind of resin as the adherend (the lid attachment portion of the container), A strong sealing state is maintained by heat-sealing, and the holding layer is formed of a resin different from the sealing layer, and is easily peeled between the sealing layer and the holding layer to provide easy opening. .

  However, with a delamination type sealant, a part of the sealant remains on the container side at the time of opening, or a film residue occurs at the time of opening, so the cohesive peeling type sealant is advantageous in that there is no such problem. is there. The cohesive peeling type sealant is the same as the delamination type in that it is formed of a seal layer, a holding layer, and a base material. However, the seal layer is made of the same kind of resin as the adherend and the same kind of resin as the holding layer. It is formed from a polymer blend of seed resins. Thereby, at the time of heat sealing, the sealing layer is partially heat-sealed with the adherend, and at the time of peeling, the sealing layer is peeled off while cohesively destroying the sealing layer itself at the interface of the polymer blended resin. Therefore, the sealing layer has both a sealing function and a peelability function. However, since the thermal fusion between the sealing layer and the adherend is partial, it is impossible to obtain a certain level of sealing strength. There is a point.

  Conventionally, as a cohesive peel type sealant, for example, Patent Document 1 discloses a seal layer that is made of a thermoplastic resin having a specific tensile breaking strength, thereby solving the problem of stringing at the time of opening. Has been. Patent Document 2 discloses a structure in which a sealing layer is made of a lacquer of a polyester resin and a urethane resin so as to leave a uniform trace on the lid. Furthermore, Patent Document 3 discloses that a sealing layer contains foamed particles to enable selective cohesive peeling and to prevent peeling failure.

JP 2005-335818 A JP 2008-7146 A JP2013-75718A

  Even in the techniques disclosed in the above Patent Documents 1 to 3, a sufficient one is still provided for the requirement to achieve both easy opening and heat seal strength while ensuring film formability as a sealing layer. This is not the case, and further improvements are desired. On the other hand, when the container itself is transparent, such as when the food container is made of polyethylene terephthalate resin, the lid material is also required to be transparent.

  The present invention is a thermoplastic resin composition having an easy-opening property by cohesive peeling, wherein the heat-sealing strength is sufficiently high, and a sealing layer excellent in easy-opening property, transparency, etc. is formed with good moldability. It is an object of the present invention to provide a thermoplastic resin composition that can be formed, a lid material for an easily openable container having a seal layer formed of the thermoplastic resin composition, and an easily openable container having the lid material.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by blending a specific fusion component, an aggregating release component, and a moldability auxiliary component. Thus, the present invention has been completed. That is, the gist of the present invention is as follows [1] to [8].

[1] A thermoplastic resin composition comprising the following components (A) to (C).
Component (A): Polyester having melting peak temperature of 110 to 150 ° C. Component (B): Styrenic thermoplastic elastomer having styrene content of less than 25% by weight (C) Component: Amorphous polyester and / or polyolefin

[2] The total amount of the component (A), the component (B) and the component (C) is 10 to 90% by weight of the component (A), 3 to 50% by weight of the component (B), and the component (C). The thermoplastic resin composition according to [1], containing 5 to 50% by weight.

[3] The thermoplastic resin composition according to [1] or [2], comprising polyethylene having a density of 0.850 to 0.980 g / cm ³ as the component (C).

[4] As the component (C), the terephthalic acid unit is contained in an amount of 80 mol% or more based on the total dicarboxylic acid unit, the ethylene glycol unit is composed of 60 to 80 mol%, and the cyclohexanedimethanol unit is composed of 20 to 20 The thermoplastic resin composition according to any one of [1] to [3], comprising an amorphous polyester containing 40 mol%.

[5] The thermoplastic resin composition according to any one of [1] to [4], wherein the glass transition temperature (Tg) of the component (A) is −80 to 0 ° C.

[6] An easily-openable container lid member having a seal layer formed of the thermoplastic resin composition according to any one of [1] to [5].

[7] An easy-open container having the lid for easy-open containers described in [6].

[8] An easily openable container comprising the easily openable container lid material according to [6] and a container made of polyethylene terephthalate resin.

According to the thermoplastic resin composition of the present invention, a heat-sealing strength is sufficiently high, and a sealing layer excellent in easy-opening property, transparency and the like can be formed with good moldability. Moreover, according to this invention, the lid | cover material for easily openable containers and an easily openable container obtained using this thermosetting resin composition are provided.

  Embodiments of the present invention will be described in detail below, but the following descriptions are examples (representative examples) of the embodiments of the present invention, and the present invention is not limited to these contents unless it exceeds the gist. Not.

The thermoplastic resin composition of the present invention includes the following components (A) to (C). Of those that can be understood as corresponding to the polyester of component (A), those that correspond to the polyester of component (C) are not regarded as component (A), but are regarded as component (C).
Component (A): Polyester having melting peak temperature of 110 to 150 ° C. Component (B): Styrenic thermoplastic elastomer having styrene content of less than 25% by weight (C) Component: Amorphous polyester and / or polyolefin

  In the present invention, the component (A) functions as a fusion component responsible for heat sealability, the component (B) is a component responsible for cohesive peelability (easy opening), and the component (C) is molded. It functions as a moldability auxiliary component for improving the properties. The thermoplastic resin composition of the present invention includes these (A) component fusion component, (B) component cohesive peelability (easy-opening property), (C) component moldability auxiliary component, By including, the sealing layer excellent in easy-opening property and heat-sealing property can be formed on the basis of favorable moldability.

In the present invention, the component (A) functions as a fusing component responsible for heat sealability, the component (B) is an agglomerated release component responsible for agglomerated releasability (easy openability), and the component (C). Functions as a moldability auxiliary component for improving moldability. The thermoplastic resin composition of the present invention contains these (A) component fusion component, (B) component cohesive release component, and (C) component moldability auxiliary component, so that it can be easily opened. In addition, it is possible to form a seal layer excellent in heat sealability with good moldability.
[(A) component]
The component (A) used in the thermoplastic resin composition of the present invention is a polyester having a melting peak temperature of 110 to 150 ° C. The thermoplastic resin composition of the present invention is imparted with heat sealability by including the component (A).

  The polyester (A) is produced by an esterification reaction between a dicarboxylic acid and a polyhydric alcohol or an ester exchange reaction between a dicarboxylic acid ester and a polyhydric alcohol. Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid, succinic acid, suberic acid, and sebacic acid. The polyhydric alcohol is preferably a diol, for example, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, pentaethylene glycol, 2,2-dimethyltrimethylene glycol, hexamethylene glycol, neo Examples include pentyl glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Said dicarboxylic acid and / or its ester, and a polyhydric alcohol can be used by arbitrary combinations. For example, terephthalic acid / ethylene glycol copolymer, 2,6-naphthalenedicarboxylic acid / ethylene glycol copolymer, terephthalic acid / isophthalic acid / 1,4-butanediol copolymer, terephthalic acid / adipic acid / 1 , 4-butanediol copolymer, terephthalic acid / isophthalic acid / 1,4-butanediol / polytetramethylene ether glycol copolymer, and the like.

The (A) component polyester used in the present invention has a melting peak temperature of 150 ° C. or lower, and therefore has a function of fusing from a low temperature to an adherend at this temperature or lower. From the viewpoint of making this function better, the melting peak temperature is preferably 145 ° C. or lower, and more preferably 140 ° C. or lower. On the other hand, the polyester of component (A) has a melting peak temperature of 110 ° C. or higher. For this reason, after fusing to the adherend, during the heat treatment of the container (easy-open container) or high temperature into the container It has a function of preventing the sealant layer from being peeled off (peeling strength is lowered) at the time of injection of an object. From the viewpoint of making this function better, the melting peak temperature is preferably 115 ° C. or higher.

  Moreover, it is preferable from a viewpoint of the blocking resistance of a film that the glass transition temperature (Tg) of (A) component is -80 degreeC or more. From this viewpoint, the glass transition temperature of the component (A) is preferably −70 ° C. or higher, and more preferably −65 ° C. or higher. On the other hand, the upper limit of the glass transition temperature (Tg) of the component (A) is not particularly limited, but is usually 0 ° C. or lower.

In addition, the melting peak temperature and glass transition temperature of (A) component can be measured according to JISK7121. Specifically, the following steps (1) to (3) are sequentially performed using a differential scanning calorimeter (DSC 6220, manufactured by SSI Nanotechnology Inc.) to measure the melting behavior of the polyester resin. In each step, time is plotted on the horizontal axis, and the heat of fusion is plotted on the vertical axis to obtain a melting curve. The peak observed in step (2) is the crystallization peak, and the peak observed in step (3) is the melting peak. .
Step (1): About 6 mg of the sample is heated from room temperature to 170 ° C. at a rate of 100 ° C./min, and held for 3 minutes after the temperature increase is completed.
Step (2): The temperature is decreased from 170 ° C. to −80 ° C. at a rate of 10 ° C./min, and held for 3 minutes after the temperature decrease.
Step (3): The temperature is raised from −80 ° C. to 170 ° C. at a rate of 10 ° C./min.

  (A) Polyester of a component can be obtained as a commercial item. For example, a corresponding product can be selected and used from “Byron (registered trademark)” series manufactured by Tohobo Co., Ltd. and “ECOFLEX (registered trademark)” manufactured by BASF. In addition, although it may be used by 1 type as polyester of (A) component, you may use it combining two types with different physical properties, such as a dicarboxylic acid component, a diol component, or a glass transition temperature.

[Component (B)]
The component (B) used in the thermoplastic resin composition of the present invention is a styrene elastomer having a styrene content of less than 25% by weight. When the styrene content of the component (B) is less than 25% by weight, transparency is improved when a thermoplastic resin composition containing the component (A) and the component (C) is obtained.

  The type of the styrene-based thermoplastic elastomer used for the component (B) is not particularly limited as long as the styrene content is less than 25% by weight. Usually, a polymer block mainly composed of a vinyl aromatic compound and flexibility are provided. What has a polymer block to provide is used. Specifically, it is obtained by hydrogenating a block copolymer having a polymer block mainly composed of a vinyl aromatic compound and a polymer block mainly composed of butadiene and / or isoprene and / or the block copolymer. And hydrogenated block copolymers.

Here, the “polymer mainly composed of a vinyl aromatic compound” means a polymer obtained by polymerizing a monomer mainly composed of a vinyl aromatic compound, and hereinafter referred to as “polymer block P” or “block P”. May be abbreviated. The “polymer mainly composed of butadiene and / or isoprene” means a polymer obtained by polymerizing a monomer mainly composed of butadiene and / or isoprene, and hereinafter referred to as “polymer block Q” or “block Q”. May be abbreviated. Here, “mainly” means 50 mol% or more. Further, a block copolymer having at least two polymer blocks P and at least one polymer block Q and / or a hydrogenated block copolymer obtained by hydrogenating the block copolymer are preferable.

  The vinyl aromatic compound of the monomer constituting the polymer block P is not limited, but styrene derivatives such as styrene, α-methylstyrene, chloromethylstyrene are preferable. Among these, it is preferable to mainly use styrene. The polymer block may contain a monomer other than the vinyl aromatic compound as a raw material.

More preferably, the block Q is butadiene alone, isoprene alone, butadiene or isoprene. The block Q may contain monomers other than butadiene and isoprene as raw materials. Further, the block Q may be a hydrogenated derivative obtained by hydrogenating a double bond having after polymerization. Although the hydrogenation rate of the block Q is not limited, 50-100 weight% is preferable and 80-100 weight% is preferable. When the block Q is hydrogenated within the above range, the thermal stability tends to be improved. The same applies to the case where the block P uses a diene component as a raw material. The hydrogenation rate can be measured by ¹³ C-NMR.

The styrene thermoplastic elastomer of component (B) has a styrene content of less than 25% by weight, which makes the thermoplastic resin composition more transparent. The styrene content of component (B) is preferably less than 20% by weight. On the other hand, the lower limit of the styrene content of the component (B) is usually 5% by weight or more, preferably 8% by weight or more. In the present invention, the “styrene content” in the component (B) includes not only the content of styrene units but also the content of structural units in which atoms or atomic groups other than hydrogen atoms are substituted on the aromatic ring of the styrene units. Used in meaning. The styrene content can be measured by ¹³ C-NMR.

  When the copolymer having the block P and the block Q is used as the styrene-based thermoplastic elastomer of the component (B), the chemical structure may be any of linear, branched, radial, etc. The block copolymer represented by the following formula (1) or (2) is preferable, and the structure of the following formula (1) is more preferable from the viewpoint of adhesiveness.

Furthermore, the block copolymer represented by the following formula (1) or (2) is more preferably a hydrogenated derivative (hereinafter sometimes abbreviated as a hydrogenated block copolymer). When the copolymer represented by the following formula (1) or (2) is a hydrogenated block copolymer, the adhesiveness of the thermoplastic resin composition of the present invention tends to be good.
P- (QP) _m (1)
(PQ) _n (2)
(In the formula, P represents the polymer block P, Q represents the polymer block Q, m represents an integer of 1 to 5, and n represents an integer of 2 to 5.)

  In the formula (1) or (2), m and n are preferably large in terms of lowering the order-disorder transition temperature as a rubbery polymer, but small in terms of ease of production and cost. . In the present invention, m and n are preferably given by integers of 1 to 5, more preferably 2 to 4.

  The block copolymer or hydrogenated block copolymer (hereinafter collectively referred to as “(hydrogenated) block copolymer”) is represented by the formula (2) because it is excellent in rubber elasticity. ) A (hydrogenated) block copolymer represented by formula (1) is preferred to a block copolymer, and (hydrogenated) block copolymer represented by formula (1) wherein m is 3 or less. (Hydrogenated) block copolymer represented by the formula (1) in which m is 2 or less is more preferable.

The method for producing the component (B) styrene-based thermoplastic elastomer is not particularly limited as long as the above structure and physical properties can be obtained. Specifically, for example, it can be obtained by performing block polymerization in an inert solvent using a lithium catalyst or the like. In addition, a known method such as hydrogenation (hydrogenation) of the block copolymer can be employed, for example, in an inert solvent in the presence of a hydrogenation catalyst.

  The number average molecular weight of the (B) component styrene-based thermoplastic elastomer is not limited, but is usually 250,000 or less, preferably 150,000 or less, more preferably 120,000 or less, and still more preferably 100,000 or less. The number average molecular weight of the styrenic thermoplastic elastomer is not limited, but is usually 20,000 or more, preferably 40,000 or more, more preferably 50,000 or more. When the number average molecular weight of the styrenic thermoplastic elastomer is within the above range, the moldability tends to be good. In addition, the number average molecular weight of (B) component styrene-type thermoplastic elastomer is the value of polystyrene conversion measured by gel permeation chromatography (Hereinafter, it may abbreviate as GPC.).

  Although the melt flow rate (MFR) in JIS K7210 (230 degreeC / 2.16kgf) of (B) component is not limited, Preferably it is 0.1 g / 10min or more, More preferably, it is 0.3 g / 10min or more The amount is preferably 100 g / 10 minutes or less, more preferably 50 g / 10 minutes or less, still more preferably 30 g / 10 minutes or less, and particularly preferably 10 g / 10 minutes or less. When the MFR of the component (B) is within the above range, the moldability tends to be good.

  The glass transition temperature of component (B) according to ISO 11357-2 is not limited, but is preferably -80 ° C or higher, more preferably -70 ° C or higher, and preferably 30 ° C or lower, more preferably It is 20 degrees C or less, More preferably, it is 0 degrees C or less. When the glass transition temperature of the component (B) is within the above range, the blocking resistance of the film tends to be good.

  The hardness of the component (B) is not particularly limited, but is hardness Shore A (JIS K6253), preferably 20 or more, more preferably 25 or more, still more preferably 30 or more, and particularly preferably 35 or more. On the other hand, it is preferably 95 or less, more preferably 90 or less, and still more preferably 85 or less. When the hardness of the component (B) is within the above range, the flexibility tends to be good.

  A commercial item can also be used for the styrene-conjugated diene block copolymer used as (B) component of this invention. As a commercial item, applicable thing can be suitably selected and used from "Tough tech (trademark)" series etc. by Asahi Kasei Chemicals.

[Component (C)]
(C) component used by this invention is an amorphous polyester and / or polyolefin. As the component (C), only one type of amorphous polyester or one type of polyolefin may be used, and one or more types of amorphous polyester and one or more types of polyolefin are used in combination. Also good.

<Amorphous polyester>
The amorphous polyester that can be used as the component (C) is a polyester that does not substantially exhibit crystallinity. In particular, in the measurement by the differential scanning calorimeter described above in the component (A), the polyester does not have a clear melting peak temperature in a temperature range of 50 ° C. to 300 ° C., specifically in this temperature range. Means that the heat of crystal fusion (ΔH) is 1 J / g or less.

Examples of the amorphous polyester that can be used as the component (C) include those obtained by replacing the terephthalic acid unit of poly (ethylene terephthalate) with other dicarboxylic acid units and / or the ethylene glycol unit of poly (ethylene terephthalate). And the like that are made amorphous by substituting a part of these with other diol units. The term “dicarboxylic acid unit” as used herein means a unit derived from dicarboxylic acid if it is an amorphous polyester produced by an esterification reaction, and is an amorphous polyester produced by an ester exchange reaction. Means a unit derived from a dicarboxylic acid diester.

  In such an amorphous polyester, as dicarboxylic acid units other than terephthalic acid units, 1,2-cyclohexanedicarboxylic acid units, 1,3-cyclohexanedicarboxylic acid units, 1,4-cyclohexanedicarboxylic acid units, 1,4 -Alicyclic dicarboxylic acid units such as decahydronaphthalenedicarboxylic acid units and 1,5-decahydronaphthalenedicarboxylic acid units; phthalic acid units, isophthalic acid units, phenylenedioxydicarboxylic acid units, 4,4'-diphenyldicarboxylic acid Unit, 4,4′-diphenyl ether dicarboxylic acid unit, 4,4′-diphenyl ketone dicarboxylic acid unit, 4,4′-diphenoxyethane dicarboxylic acid unit, 4,4′-diphenylsulfone dicarboxylic acid unit, 2,6- Aromatic dicarboxylic such as naphthalene dicarboxylic acid unit Unit: Aliphatic dicarboxylic acid unit such as succinic acid unit, glutaric acid unit, adipic acid unit, pimelic acid unit, suberic acid unit, azelaic acid unit, sebacic acid unit, undecadicarboxylic acid unit, dodecadicarboxylic acid unit, etc. It is done. The dicarboxylic acid unit mentioned above may contain only 1 type, or may contain 2 or more types.

  Moreover, as diol units other than ethylene glycol, 1,2-cyclopentanediol unit, 1,3-cyclopentanediol unit, 1,2-cyclopentanedimethanol bis (hydroxymethyl) tricyclo [5.2.1. 0] decane unit, 5-membered ring diol unit such as 1,3-cyclopentanedimethanol bis (hydroxymethyl) tricyclo [5.2.1.0] decane unit; 1,2-cyclohexanediol unit, 1,3- Cyclohexanediol unit, 1,4-cyclohexanediol unit, 1,2-cyclohexanedimethanol (1,2-CHDM) unit, 1,3-cyclohexanedimethanol (1,3-CHDM) unit, 1,4-cyclohexanedim Methanol (1,4-CHDM) unit, 2,2-bis- (4-hydroxycyclo) Xylyl) -propane units and other cyclohexanedimethanol units; trimethylene glycol units, 1,4-butanediol units, pentamethylene glycol units, hexamethylene glycol units, octamethylene glycol units, decamethylene glycol units, neopentyl glycol units, Aliphatic diol units such as diethylene glycol; xylylene glycol units, 4,4′-dihydroxybiphenyl units, 2,2-bis (4′-hydroxyphenyl) propane units, 2,2-bis (4′-β-hydroxyethoxy) And aromatic diol units such as phenyl) propane unit, bis (4-hydroxyphenyl) sulfone unit, and bis (4-β-hydroxyethoxyphenyl) sulfone unit acid. Among these, it is preferable that a cyclohexane dimethanol unit is included as a diol unit. The diol units listed above may contain only one type or two or more types.

  Among these, as an amorphous polyester that can be used for the component (C), polyethylene terephthalate containing a cyclohexanedimethanol unit as a diol unit is preferable. In particular, the terephthalic acid unit is contained in an amount of 80 mol% or more based on the total dicarboxylic acid unit, and the ethylene glycol unit is contained in an amount of 60 to 80 mol% and the cyclohexanedimethanol unit is contained in an amount of 20 to 40 mol% based on the total diol unit. preferable.

The glass transition temperature (Tg) of the amorphous polyester (C) is preferably 45 ° C. or higher, more preferably 55 ° C. or higher. It is preferable from a heat resistant viewpoint that the glass transition temperature of amorphous polyester is more than the said lower limit. Further, the glass transition temperature of the amorphous polyester is preferably 90 ° C. or lower, more preferably 80 ° C. or lower. When the glass transition temperature is less than or equal to the above upper limit value, the crystallinity is lowered, whereby the transparency is excellent, and the heat sealability is excellent. The glass transition temperature can be measured by a conventional method by using a differential scanning calorimeter (DSC) or the like in the same manner as the component (A) described above, and measured at a rate of temperature increase of 10 ° C./min. It means the temperature at the inflection point of the heat flow. The glass transition temperature of the amorphous polyester can be controlled by appropriately selecting and using the dicarboxylic acid component and the diol component described above.

  The intrinsic viscosity (IV) of the amorphous polyester of component (C) is not particularly limited, but a lower intrinsic viscosity is preferable in view of easy molding because the melt viscosity is also lowered. Specifically, the intrinsic viscosity (IV) obtained by measuring amorphous polyester using a mixed solution of phenol / tetrachloroethane (weight ratio 1/1) as a solvent using an Ubbelohde viscometer at 30 ° C. It is preferably 1.5 dL / g or less, and from the viewpoint of physical properties such as strength, it is preferably 0.3 dL / g or more.

(C) As an amorphous polyester of a component, it can obtain as a commercial item. For example, the corresponding product can be selected from the “Easter (registered trademark) copyester” series manufactured by Eastman Chemical Co.

<Polyolefin>
The polyolefin that can be used as the component (C) is a homopolymer or copolymer of an olefin having about 2 to 20 carbon atoms such as ethylene, propylene, butene-1, pentene-1, hexene-1, or the like. Examples include copolymers of olefins and copolymerizable vinyl monomers, for example, vinyl acetate, acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, maleic anhydride and other unsaturated organic acids or anhydrides thereof. It is done. In addition, in the copolymer of an olefin and a copolymerizable vinyl monomer, the content of olefin units is 50% by weight or more. Here, the copolymer includes random, block and graft copolymers. In addition, what corresponds to (D) component demonstrated below shall not be considered as (C) component.

  More specifically, as the polyolefin that can be used as the component (C), polyethylene, polypropylene, ethylene-propylene random copolymer, ethylene / propylene block copolymer produced by a high pressure method, a medium pressure method, or a low pressure method, A propylene / butene-1 random copolymer, a propylene / ethylene / butene-1 random copolymer, a copolymer of propylene, an α-olefin having 5 to 12 carbon atoms and optionally ethylene or butene-1, ethylene -Vinyl acetate copolymers and the like are mentioned, and among these, polyethylene, polypropylene, ethylene / vinyl acetate copolymers (those having an ethylene unit content of less than 50% by weight), etc. are preferred, especially high density polyethylene. Polyethylene such as low density polyethylene and linear polyethylene Preferred. “Polypropylene” means a component containing more than 50% by weight of a propylene unit as a constituent unit, and “polyethylene” means a component containing more than 50% by weight of an ethylene unit as a constituent unit. As the component (C), polyethylene is particularly preferable from the viewpoint of moldability.

As the polypropylene that can be used as the component (C), from the viewpoint of moldability, the melt flow rate (MFR) measured at 230 ° C. and a load of 2.16 kg according to JIS K7210 (1999) is 1.0 to 60 g / 10 min. Is preferably 2.0 to 40 g
More preferably, it is / 10 minutes.

The polyethylene that can be used as the component (C) preferably has a melt flow rate (MFR) measured at 190 ° C. and a load of 2.16 kg in accordance with JIS K7210 (1990) from the viewpoint of moldability. It is preferably 60 g / 10 minutes, and more preferably 2.0 to 40 g / 10 minutes. Moreover, the polyethylene is preferably the density from the viewpoint of heat resistance (JIS K7112) is 0.850~0.980g / cm ^3, more preferably 0.855~0.950g / cm ^3, 0. More preferably, it is 860-0.930 g / cm < ³ >.

  Furthermore, an ethylene / vinyl acetate copolymer (with an ethylene unit content of 50% by weight or less) that can be used as the component (C) is 190 ° C. according to JIS K7210 (1990) from the viewpoint of moldability. The melt flow rate (MFR) measured with a load of 2.16 kg is preferably 1.0 to 60 g / 10 min, and more preferably 2.0 to 40 g / 10 min.

  In addition, as (C) component polyolefin, 1 type of the polyolefin quoted above may be used, and 2 or more types of polyolefin from which a raw material composition and a physical property differ may be used in combination.

  (C) Component polyolefin can be obtained as a commercial product. Examples of polypropylene include Novatec (registered trademark) PP series and Wintec (registered trademark) series manufactured by Nippon Polypro Co., Ltd., and appropriate products can be selected and used from these. In addition, examples of polyethylene include Novatec (registered trademark) series manufactured by Nippon Polyethylene Co., Ltd. and Creolex (registered trademark) series manufactured by Asahi Kasei Chemicals Co., Ltd. it can.

[Other ingredients]
The thermoplastic resin composition of the present invention may contain other components other than the component (A), the component (B), and the component (C). Other components include fillers; colorants such as dyes and pigments, stabilizers, plasticizers, antioxidants, light stabilizers such as UV absorbers, dispersants, thickeners, drying agents, lubricants, antistatic agents Additives such as additives; polycarbonate resin, polymethylmethacrylate resin, polyester resin (except those corresponding to (A) component and (C) component), vinyl chloride resin, styrene-based thermoplastic elastomer ((B) component) And the like, polyester-based thermoplastic elastomers (excluding those corresponding to component (A) and component (C)), and resins such as polyurethane-based thermoplastic elastomers.

[Blending amount]
The thermoplastic resin composition of the present invention contains (A) component, (B) component, and (C) component, thereby providing effects of heat seal strength, cohesive peelability (easy-opening property), transparency, and moldability. Therefore, from the viewpoint of obtaining these effects satisfactorily, the component (A) is 10 to 90% by weight and the component (B) is 3 to 50% with respect to the total amount of the components (A) to (C). It is preferable to contain 5 to 50% by weight of component (C), 15 to 85% by weight of component (A), 4 to 45% by weight of component (B), and 8 to 45% by weight of component (C). % Content is more preferable.

When the content ratio of the component (A), which is a component responsible for fusibility, is equal to or higher than the above lower limit value, the heat seal strength tends to be more favorable. When the content ratio of the component (C) increases, the cohesive peelability and moldability tend to be better. Further, when the content ratio of the component (B) which is a component responsible for the cohesive peelability is equal to or higher than the above lower limit value, the cohesive peelability tends to be better, and when it is equal to or lower than the above upper limit, the component (A) When the content ratio of the component (C) increases, the heat seal strength and moldability tend to be better. In addition, when the content ratio of the component (C), which is a component responsible for assisting moldability, is less than or equal to the above lower limit value, the moldability tends to be better, and when it is less than or equal to the above upper limit value, the component (A) is relatively And (B)
When the content ratio of the components increases, the heat seal strength and the cohesive peelability tend to be better.

  In the case where the thermoplastic resin composition of the present invention contains other components other than the components (A) to (C), in order to sufficiently obtain the functions of the components (A) to (C), in the thermoplastic resin composition The total content of the other components is preferably 30% by weight or less, more preferably 20% by weight or less, and further preferably 10% by weight or less based on the total thermoplastic resin composition. preferable.

  The method for obtaining the thermoplastic resin composition of the present invention is not particularly limited as long as the raw material components are uniformly dispersed. That is, by mixing the above-described raw material components simultaneously or in any order, a thermoplastic resin composition in which the respective components are uniformly distributed can be obtained. In the production of the thermoplastic resin composition of the present invention, when the thermoplastic resin composition is obtained by blending the components (A) to (C), the component (D) blended as necessary, and other components. These components are mixed using various known methods such as a tumbler blender, a V blender, a ribbon blender, a Henschel mixer, etc., and then mixed with a single screw extruder, twin screw extruder, Banbury mixer, kneader, etc. A thermoplastic resin composition can be obtained by melt-kneading.

  The mixing method and mixing conditions for mixing the raw material components are not particularly limited as long as the raw material components are uniformly mixed. From the viewpoint of productivity, a single screw extruder or a twin screw extruder is used. A known melt-kneading method such as a continuous kneader and a batch kneader such as a mill roll, a Banbury mixer, and a pressure kneader is preferred. The temperature at the time of melt mixing may be a temperature at which at least one of the raw material components is in a molten state, but usually a temperature at which all the components used are melted is selected, and in the present invention, it is usually performed at 180 to 300 ° C. be able to.

[Film forming]
The thermoplastic resin composition of the present invention can be easily formed as a sealing layer (sealing layer film) by various film forming methods such as extrusion lamination molding, T-die molding, and air-cooled inflation molding. The thickness of the sealing layer film is usually 2 to 100 μm, and preferably 5 to 30 μm. When the thickness of the sealing layer is within the above range, in view of obtaining sufficient heat-sealing strength, in view of obtaining cohesive peelability, in application to an easy-opening lid of an easy-open container, the thickness of the lid Is preferable from the viewpoint of setting the value to an appropriate range.

[Easy-opening lid / Easy-opening container]
By using a sealing layer (film for sealing layer) formed of the thermoplastic resin composition of the present invention, an easily openable lid material can be obtained. Moreover, this easy-open lid | cover material uses the thermoplastic resin composition of this invention as a sealing layer (film for sealing layers), and it is easy to have an easily openable lid | cover material normally by carrying out lamination | stacking integration with the base material. It can be suitably used as an openable container. In this case, a polyolefin resin layer such as polyethylene or polypropylene can be interposed as a holding layer between the seal layer film and the substrate. The thickness of the holding layer is usually about 5 to 500 μm, particularly about 10 to 100 μm.

  Examples of the base material of the easy-open lid material include aluminum foil, paper, polyester resin films represented by polyethylene terephthalate, such as stretched polyester film, stretched nylon film, polyethylene, polypropylene, and other olefin resin films, such as stretched polypropylene film. , Polystyrene film, silica-deposited stretched polyester film, aluminum-deposited stretched polyester film, other barrier films, etc. are generally applicable as long as they are used as a base material for flexible packaging materials. A suitable base material can be selected and used.

  Examples of a method for laminating and integrating the sealing layer film made of the thermoplastic resin composition of the present invention on such a substrate include a method of bonding with an adhesive such as polyurethane, polyester, or polyether. Further, the base film and the sealing layer film may be integrally formed by coextrusion lamination.

  In addition, in order to produce a lid member in which a holding layer is interposed between the sealing layer film and the substrate, the thermoplastic resin composition of the present invention is produced by a film molding method such as an inflation method or a T-die method. At the time, after laminating and molding with a holding layer made of a polyolefin resin such as polyethylene and polypropylene, or after laminating the holding layer and the seal layer by coextrusion lamination molding with a polyolefin resin such as polyethylene and polypropylene, Furthermore, a sealing layer and a holding layer are formed on a base material layer made of various thermoplastic resins such as a method of pasting base materials, aluminum foil, paper, polyester resins typified by polyethylene terephthalate, olefin resins such as polyethylene and polypropylene. Examples include a method of manufacturing by forming a laminate film by extrusion lamination molding That.

  The easy-opening lid material made of a laminated film or laminated sheet of the obtained seal layer / base material or seal layer / holding layer / base material is disposed in the opening portions of various containers and along the flange portions of the opening portions. It can be used for sealing a container by heat-pressing and heat-sealing.

  The heat sealing conditions at this time are as follows: the melting point of the component (A) used or a temperature about 50 ° C. higher than the melting point of the component (A), for example, about 110 to 200 ° C., and a pressure of 0.1 to 0 It is preferable that the pressure is about 3 MPa and the heat sealing time is about 1 to 10 seconds.

  The constituent material of the easy-open container to which the easy-open lid using the thermoplastic resin composition of the present invention is applied includes polyethylene resin, polypropylene resin, polyethylene terephthalate resin, polystyrene resin, polycarbonate resin, and blends thereof. Of these, the easy-open container is preferably made of polyethylene terephthalate.

  The easy-opening lid material having the sealing layer formed of the thermoplastic resin composition of the present invention, and the easy-opening container having the easy-opening lid material are any applications that require easy opening of the lid material. However, it can be particularly preferably used in food and beverage containers.

  EXAMPLES The present invention will be described more specifically with reference to the following examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist. The values of various production conditions and evaluation results in the following examples have meanings as preferred values of the upper limit or lower limit in the embodiments of the present invention, and the preferred ranges are the upper limit or lower limit values described above, and It may be a range defined by a combination of values of the examples or values between the examples.

[Raw materials]
The raw materials used in the following examples and comparative examples are as follows.
<(A) component>
A-1:
Byron (registered trademark) GM913 manufactured by Toyobo Co., Ltd.
Low melting crystalline polyester (melting point 135 ° C., glass transition temperature −60 ° C., terephthalic acid / isophthalic acid / 1,4-butanediol / polytetramethylene ether glycol copolymer (dicarboxylic acid unit: 66 mol% terephthalic acid unit, Isophthalic acid unit 34 mol%))

<(B) component>
B-1:
Asahi Kasei Chemicals Co., Ltd. Styrenic thermoplastic elastomer “Tuftec (registered trademark) H1221” (styrene content: 12% by weight, density: 0.89 g / cm ³ , MFR (230 ° C./2.16 kgf (JIS K7210)): 4 .5g / 10min, hardness Shore A (JIS
K6253): 42)
b-1 (for comparative example):
Modified polyolefin obtained by impregnating and polymerizing low density polyethylene with styrene (styrene content: 50% by weight)

<(C) component>
C-1:
PET-G G6763 manufactured by Eastman Chemical Company
Amorphous polyester (terephthalic acid unit 100 mol%, ethylene glycol unit: 70 mol%, cyclohexanedimethanol unit: 30 mol%)
C-2:
LDPE Novatec LC607 made by Nippon Polyethylene
Low density polyethylene (density 0.919 g / cm ³ , MFR (JIS K7210 (1990) (190 ° C., 2.16 kgf)): 8 g / 10 min)

  In addition, as a PET film used for the production of the evaluation film, “Toyobo Ester (registered trademark) film E5102” (thickness: 25 μm) manufactured by Toyobo Co., Ltd. was used, and as the adhesive, a two-component curable polyurethane manufactured by Toyo Morton Co., Ltd. was used. A base adhesive “TM329” and a curing agent “CAT-8B” diluted with ethyl acetate were used.

[Examples 1 and 2, Comparative Examples 1 and 2]
<Film formation of sealant film>
Using each component shown in Table-1 at the blending ratio shown in Table-1, kneading at 160 to 220 ° C. with a twin screw extruder “KZW15TWIN-45MG-NH” (manufactured by Technobell Co., Ltd.), and using a T die Then, film formation was performed under the following conditions to form a sealant film having a thickness of 50 μm.
Molding temperature: 220 ° C
Screw rotation speed: 300rpm
Molding speed: 4-5m / min

<Production of evaluation film>
After applying an adhesive to one side of the PET film using a coater (manufactured by Tester Sangyo) and evaporating the solvent, each adhesive film was bonded to the adhesive-coated surface and dried in an oven at 40 ° C overnight. Each was used as a film for evaluation.

<Evaluation of heat seal strength>
Each evaluation film and the following adherend were cut into a size of 70 mm × 100 mm, and the evaluation film was placed on the adherend so that the sealant film side was in contact therewith. Heat sealing was performed under the following conditions using a heat sealer (manufactured by Sagawa Seisakusho Co., Ltd.), and the central portion in the length direction of the evaluation film was heat sealed to a width of 10 mm.
Pressure: 0.2MPa
Time: 1.0 seconds Seal bar: 10mm (width)
Temperature: 130 ° C or 160 ° C
Substrate: “Novaclear (registered trademark) SG007” manufactured by Mitsubishi Chemical (A-PET sheet thickness: 0.3 mm)

  Thereafter, the portions of the evaluation film that were not heat-sealed were pulled apart from each other and peeled to measure the heat seal strength. The results are shown in Table 1. The heat seal strength is preferably 4 to 20 N / 15 mm in terms of both easy opening and seal strength.

<Transparency (haze)>
Each evaluation film was cut into a size of 30 mm × 30 mm. Using this, the haze value was measured with a turbidimeter (“NDH2000” manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K-7136. The smaller the haze value, the better the transparency.

<Evaluation results>
The evaluation results of each example and comparative example are as shown in Table 1 below.

  From Table 1, Examples 1 and 2 and Comparative Examples 1 and 2 corresponding to the thermoplastic resin composition of the present invention containing the components (A) to (C) are excellent in easy-openability and sealing strength. It is. On the other hand, comparing each of Examples 1 and 2 with Comparative Examples 1 and 2 using “b-1” that does not correspond to the component (B) instead of “B-1”, Example 1 2 shows that the haze value is smaller than those of Comparative Examples 1 and 2, and the transparency is excellent.

Claims (8)

A thermoplastic resin composition comprising the following components (A) to (C).
Component (A): Polyester having melting peak temperature of 110 to 150 ° C. Component (B): Styrenic thermoplastic elastomer having styrene content of less than 25% by weight (C) Component: Amorphous polyester and / or polyolefin   The total amount of the component (A), the component (B) and the component (C) is 10 to 90% by weight for the component (A), 3 to 50% by weight for the component (B), and 5 to 50 for the component (C). The thermoplastic resin composition according to claim 1, which is contained by weight. (C) The thermoplastic resin composition of Claim 1 or 2 containing the polyethylene of a density of 0.850-0.980g / cm < ³ > as a component.   (C) As a component, it contains 80 mol% or more of terephthalic acid units with respect to all dicarboxylic acid units, and it contains 60 to 80 mol% of ethylene glycol units and 20 to 40 mol% of cyclohexanedimethanol units with respect to all diol units. The thermoplastic resin composition of any one of Claims 1 thru | or 3 containing the amorphous polyester to contain.   The thermoplastic resin composition according to any one of claims 1 to 4, wherein the glass transition temperature (Tg) of the component (A) is -80 to 0 ° C.   An easily-openable container lid member having a seal layer formed of the thermoplastic resin composition according to any one of claims 1 to 5.   An easy-open container having the lid for an easy-open container according to claim 6.   An easy-open container comprising the lid for easy-open containers according to claim 6 and a container made of polyethylene terephthalate resin.