JPH05214228A - Easily releasable heat-sealable resin composition, packaging film or sheet, composite packaging material and sealed container - Google Patents

Abstract

PURPOSE:To obtain the title composition having sufficient adhesiveness to and suitable releasability from a packaging material whose surface of contact with the contents is made of a polyester resin by mixing an amorphous or lowly crystalline polyester with a specified polyester elastomer in a specified ratio. CONSTITUTION:The title composition is prepared by mixing 100 pts.wt. amorphous or lowly crystalline polyester with 10-200 pts.wt. polyester elastomer of a glass transition temperature of 10 deg.C or below or by mixing 100 pts.wt. amorphous or lowly crystalline polyester with 5-100 pts.wt. thermoplastic styrene elastomer comprising a hydrogenated SBS copolymer or both this elastomer and 0-100 pts.wt. polyester elastomer having a glass transition temperature of 10 deg.C or below.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an easily peelable heat-sealing resin composition, a packaging film or sheet, a composite packaging material, and the like, which are used for packaging foods, high-grade Western confectioneries, medical products, aromatics, cosmetics and the like. Regarding a sealed container.

[0002]

2. Description of the Related Art Conventionally, the following techniques have been used in easily peelable heat-sealed packaging using plastic.

(A) The opening of a packaging container body and lid made of an olefin resin (for example, polypropylene) or a vinyl chloride resin, or the opening of a packaging pouch is made into a base resin made of a resin of the same kind as that of polyethylene or polyethylene. Resin composition for heat sealing, which is made by adding a resin having poor compatibility with the base resin such as wax and tackifier, or vinyl chloride vinyl acetate polymer resin, low density polyethylene resin, ionomer resin, or ethylene vinyl acetate copolymer Heat seal using a heat sealing resin such as a united resin.

(B) A lid made of a composite material in which another plastic film, metal foil, paper or the like is laminated on one surface of a film or sheet made of the heat sealing resin composition or the heat sealing resin of (a) above. The material is heat-sealed into a container body made of an olefin resin (for example, polypropylene) or a vinyl chloride resin by using a heat-sealing resin composition or a film or sheet made of the heat-sealing resin.

(C) A heat-sealing resin composition or a heat-sealing resin is used to form an opening of a packaging pouch formed of a film or sheet comprising the heat-sealing resin composition or the heat-sealing resin. Heat-sealing using the following film or sheet.

(D) The opening of a packaging container body and lid made of an olefin resin (for example, polypropylene) or vinyl chloride resin, or a pouch for packaging is provided with a base resin made of an ethylene vinyl acetate copolymer resin, a wax, Bonding using a hot melt adhesive mixed with a tackifier.

However, the above prior arts (a) to (d)
Was effective for sealing the packaging container body and lid made of general-purpose resin such as olefin resin (eg polypropylene) or vinyl chloride resin, or the opening of the packaging pouch. And pouches had the following problems. That is, since the transparency is poor and the resin odor may be transferred to the contents, it is unsuitable for containers such as cosmetics, fragrances, and foods with a strong odor, and recently the tendency to gourmet food has increased. Therefore, there is a strong demand for conversion to dechlorinated materials because the taste of the contents is not changed and the environmental protection of the earth is increasing. The above-mentioned conventional containers have not been able to sufficiently meet such demands.

Therefore, as a container for solving such a problem, a container body and a lid made of polyester resin, and a packaging material such as a pouch material have come to be used. However, when the packaging material made of a polyester resin is heat-sealed with the resin for heat-sealing shown in (a) to (c) above, there is a problem that the adhesive strength is insufficient and the sealing property is poor. Further, when a polyester resin is used as the heat-sealing resin, although it has excellent heat-sealing property, it does not have easy peeling property, so it is inconvenient because a large force is required for opening, Even when peeled off, there is a problem that the heat-sealing resin remains on the opening surface and is unsightly. Therefore, it is necessary to use a knife or the like to open the bag, which is troublesome.

An object of the present invention is to solve the above-mentioned problems and to provide a peeling property which has a sufficient adhesive force and a suitable peeling property with respect to a packaging body whose surface contacting the contents is a polyester resin. It is intended to provide a resin composition for heat sealing, a film or sheet for packaging, a composite packaging material, and a sealed container.

[0010]

The first easily peelable heat-sealing resin composition according to the present invention has a glass transition point of 10 ° C. or lower with respect to 100 parts by weight of an amorphous or low-crystalline polyester. Polyester elastomer 10-20
It is composed of 0 parts by weight.

In the above-mentioned easy-peelable heat-sealing resin composition, the compounding ratio of the amorphous or low-crystalline polyester and the polyester elastomer is 10 to 200 parts by weight of the latter with respect to 100 parts by weight of the former. If the blending ratio of the polyester elastomer to 100 parts by weight of the amorphous or low crystalline polyester is less than 10 parts by weight, the compatibility with the amorphous or low crystalline polyester is too good and the easy peeling property is hard to be expressed. When the amount exceeds 200 parts by weight, sufficient heat sealing property cannot be obtained, adhesion is exhibited even at room temperature and handling aptitude is deteriorated, thermal stability is lowered, and allowable range of molding conditions is narrowed. This is because there is a possibility that the problem of (1) may appear, which is not preferable in any case. The mixing ratio of the polyester elastomer to 100 parts by weight of the amorphous or low crystalline polyester is preferably 10 to 80 parts by weight. The second easily peelable resin composition for heat sealing according to the present invention comprises 100 parts by weight of an amorphous or low crystalline polyester, 5 to 100 parts by weight of a styrene-based thermoplastic elastomer containing hydrogenated SBS copolymer as a component,
Of 0-100 parts by weight of a polyester elastomer having a glass transition point of 10 ° C. or less, the above-mentioned 3 components or 2
It is a mixture of components.

Of the above-mentioned second easily peelable heat-sealing resin composition, in the two-component system of low crystalline polyester and styrene thermoplastic elastomer, the latter is 5 to 100 parts by weight with respect to the former 100 parts by weight. The term "parts" means that when the mixing ratio of the styrene-based thermoplastic elastomer to the amorphous or low-crystalline polyester 100 parts by weight is less than 5 parts by weight, easy peeling does not occur and the product is completely sealed and can be easily handled by hand. This is because the packaging material cannot be peeled off, and a part of the packaging material remains on the adhesive portion to impair the appearance after opening. On the other hand, the mixing ratio of the styrene thermoplastic elastomer is 10
If the amount exceeds 0 parts by weight, sufficient sealing strength cannot be obtained, resulting in impaired hermeticity. The above mixing ratio is preferably 10 to 80 parts by weight. Further, in the three-component system, in order to further improve the sealing property and to allow the opening by hand, a polyester elastomer is added to the two-component system in an amount of 10 parts by weight per 100 parts by weight of the low crystalline polyester.
It is to be mixed up to 0 parts by weight. If it exceeds 100 parts by weight, sufficient sealing strength cannot be obtained, and thus the hermeticity is impaired. The above mixing ratio is preferably 5 to 50 parts by weight.

In any of the above polyester-based elastomers of the easily peelable heat-sealing resin composition, the glass transition point is limited to 10 ° C. or less.
This is because when the temperature exceeds ° C, the adhesive strength becomes too large and easy peeling cannot be obtained. Further, this compounding is performed by any method involving melting. For example, a single-screw or twin-screw extruder, a Banbury mixer, or other suitable device is used. Further, in the second easily peelable heat-sealing resin composition,
As the polyester elastomer, it is preferable to use a polyether-ester thermoplastic elastomer which is a polycondensation product of an aromatic polyester and an aliphatic polyether.

As the amorphous or low crystalline polyester in each of the above-mentioned easily peelable heat-sealing resin compositions, one polyester comprising at least one glycol and at least one dicarboxylic acid or its dialkyl ester is used. Alternatively, it is preferable to use a mixture of two or more of such polyesters.

As the polyester composed of one or more kinds of glycol and one or more kinds of dicarboxylic acid or its dialkyl ester, for example, a polyester composed of one kind of glycol and one kind of dicarboxylic acid or its dialkyl ester is used. For this polyester,
The lower the crystallinity after melt extrusion molding is, the better, and the crystallinity is preferably 10% or less. This is because if the crystallinity exceeds 10%, the heat sealing property tends to decrease.

The polyester composed of one or more glycols and one or more kinds of dicarboxylic acids or dialkyl esters thereof is, for example, a copolyester composed of one kind of glycol and two or more kinds of dicarboxylic acid or dialkyl ester thereof. A copolyester composed of two or more glycols and one dicarboxylic acid or dialkyl ester thereof, or a copolyester composed of two or more glycols and two or more dicarboxylic acids or dialkyl esters thereof is used. In these polyesters, the crystallinity after melt extrusion is not particularly limited, but it is preferably 10% or less.

As the monomer constituting such an amorphous or low crystalline polyester, those conventionally used can be used and are not particularly limited. Preferably, terephthalic acid is used as the main dicarboxylic acid component and ethylene glycol or 1,4-tetramethylene glycol is used as the main diol component. As other constituents, isophthalic acid, diethylene glycol, 1,4-cyclohexanedimethanol and the like are preferably used. At this time, the addition amount of the other constituents is preferably 2.5 to 25 mol% of all monomers,
More preferably, it is 10 to 15 mol%.

More specifically, the above polyesters include terephthalic acid, ethylene glycol and 1,4
A copolyester of cyclohexanedimethanol, a copolyester of terephthalic acid, ethylene glycol and diethylene glycol, a copolyester of terephthalic acid, isophthalic acid and ethylene glycol, terephthalic acid and isophthalic acid Copolyester copolymerized with 1,4-cyclohexanedimethanol, copolyester copolymerized with terephthalic acid, isophthalic acid and propylene glycol, polyester copolymerized with terephthalic acid, isophthalic acid, ethylene glycol and propylene glycol And so on.

Further, when a crystalline or amorphous or low crystalline polyester is extrusion-molded, an amorphous film having a crystallinity of 10% or less, which is obtained by rapidly cooling a film extruded from a die discharge port, Low crystalline polyesters can also be used. The monomer component used at this time is not particularly limited.

When a mixture of two or more of the above polyesters is used as the amorphous or low crystalline polyester, the mixing ratio is appropriately adjusted.

The polyester elastomer used in each of the above-mentioned easily peelable heat-sealing resin compositions includes a hard segment comprising at least one glycol and at least one dicarboxylic acid or dialkyl ester thereof, and at least one polysegment. (Alkylene oxide) glycol and 1
A copolymer with a soft segment composed of one or more kinds of dicarboxylic acids, or a mixture of two or more kinds of such copolymers and having a glass transition point of 10 ° C. or lower is used.

Examples of monomers constituting such polyester elastomers include dicarboxylic acid components of hard segment and soft segment, such as terephthalic acid, isophthalic acid, sebacic acid, adipic acid, bisbenzoic acid and naphthalenedicarboxylic acid. As the glycol component, ethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, isobutylene glycol, cyclohexanedimethanol, 1,
Examples thereof include 5-dihydroxynaphthalene, but the invention is not limited thereto.

The hard segment and the soft segment are represented by the chemical formula 1.

[0024]

[Chemical 1] In Chemical Formula 1, R ′ ″: C2 to C15, n: 5
200 and R to R ″ are divalent aliphatic or aromatic hydrocarbons.

The proportion of the soft segment in the mixture of the hard segment and the soft segment is preferably 5 to 95 mol%, and more preferably 20 to 70 mol%. When the above ratio is less than 5 mol%, incompatibility does not appear when mixed with the amorphous or low crystalline polyester, and 9
This is because if it exceeds 5 mol%, the thermal stability may be lowered and molding may be hindered, which is not preferable in any case.

The styrene-based thermoplastic elastomer used in the second easily peelable heat-sealing resin composition is a styrene-ethylene / butylene block copolymer saturated with hydrogen having a styrene content of 5 to 50% by weight. (SE
S) or styrene-ethylene / propylene block copolymer (SEP) and polyolefin.
First of packaging film or sheet according to the present invention
The whole is made of the above-mentioned first or second easily peelable heat-sealing resin composition.

A second packaging film or sheet according to the present invention is a layer (hereinafter, referred to as "the easily peelable heat-sealing resin composition" of either the first or the second above).
A seal layer) and a polyester resin layer laminated on one side of this layer.

The thickness of the first or second packaging film or sheet is preferably 10 to 500 μm.

In the first packaging film or sheet, the haze value is 5 when the thickness is 100 μm.
If it is at least%, it can be seen that the amorphous or low crystalline polyester resin and the polyester elastomer in this film or sheet have suitable incompatibility. That is, if the haze value is less than 5%, the compatibility may be so good that the easy peeling property may not be obtained. The haze value is measured by ASTM D1003.

In the second packaging film or sheet, the thickness of the sealing layer is 3 μm or more, preferably 5 to
20 μm and the thickness of the polyester resin layer is 10 μm
m or more, preferably 15 to 30 μm. This is because if the sealing layer is less than 3 μm, sufficient heat sealing property may not be obtained, and if the polyester resin layer is less than 10 μm, the strength of the film or sheet becomes too small and the suitability for the subsequent steps decreases.

In the second packaging film or sheet, when a polybutylene terephthalate (hereinafter referred to as PBT) resin is used as the polyester resin, the following characteristics are exhibited. That is, by using the PBT resin, the toughness of the film or sheet is increased, the film-forming property at the time of production is improved, and troubles such as cutting in the post-processing step can be prevented in advance. Also,
By using the PBT resin, for a thin film having a thickness of, for example, about 10 to 100 μm, flexibility as a packaging material is increased, and it is also effective for preventing permeation of aroma components and medicinal components of the contents.

This PBT resin is, for example, a polyester resin obtained by condensation polymerization using 1,4-butanediol and terephthalic acid as main monomer components.

In the PBT resin, a diol component other than 1,4-butanediol and a dicarboxylic acid component other than terephthalic acid can be used as monomer components within a range in which the original properties of the PBT resin are not lost. Examples of such diol components include ethylene glycol, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and the like. As the dicarboxylic acid component, other than terephthalic acid, isophthalic acid, sebacic acid, adipic acid, azelaic acid, succinic acid and the like can be used. A heat stabilizer, a light stabilizer, and an inorganic filler may be added to the PBT resin as long as the original characteristics of the PBT resin are not lost.

The PBT resin preferably has an intrinsic viscosity (IV) in o-chlorophenol at 25 ° C. of at least 0.6 or more. This is because if the intrinsic viscosity is less than 0.6, the film forming processability may deteriorate.

Any method can be used for laminating the seal layer and the PBT resin layer as long as it is a method generally used for laminating plastics, and is not particularly limited. For example, a coextrusion method, an extrusion lamination method, a dry lamination method, a thermal lamination method, a wet lamination method, or the like can be used. Among these, the coextrusion method is particularly effective in terms of interlaminar strength, process simplicity, and the like.

The composite packaging material according to the present invention has the above first feature.
Of at least one of a plastic film, a metal foil and a paper is laminated on one surface of the packaging film or sheet of 1) or the polyester resin layer surface of the second packaging film or sheet. As the metal foil, for example, aluminum foil, tin foil, steel foil, tin foil, etc. are used. Examples of the plastic film include biaxially stretched polyethylene terephthalate film,
A biaxially stretched nylon film, a polycarbonate film, or a laminate product of these is used.

Specifically, for example, a biaxially stretched polyamide film (15 μm) is coated with an adhesive on one surface of the first packaging film or sheet or on the polyester resin layer surface of the second packaging film or sheet. Attached via.

An aluminum foil (9 μm) and a biaxially stretched polyester film (12 μm) attached in this order via an adhesive.

Coextruded to provide an amorphous or low crystalline polyester layer (300 μm).

The following may be mentioned. Each of these shows a configuration example suitable for use as a lid material for a sealed container, but the configuration and manufacturing method are not limited to this.

The first hermetically sealed container according to the present invention comprises a container body made of a polyester resin, and the above-mentioned first or second container.
The lid member made of the packaging film or sheet is heat-sealed by using the easily peelable heat-sealing resin layer.

A second hermetically sealed container according to the present invention comprises a container body made of polyester resin and a lid member made of the above composite packaging material, which is heat sealed by using an easily peelable heat sealing resin layer. is there.

In the first and second hermetically sealed containers, the container body comprises a single amorphous or low crystalline polyester sheet or a laminated synthetic resin having an amorphous or low crystalline polyester resin layer as the innermost layer. It is preferably composed of sheets. Such a container body is manufactured from the above-mentioned sheet by a method such as pressure molding, plug assist molding, vacuum molding, injection molding, and blow molding.

A container made of the packaging material as described above is
The heat-sealed part shows stable sealing property, and its peel strength shows an optimum value of about 0.5 to 3.0 kg / 15 mm.

Another sealed container according to the present invention is the above first container.
Alternatively, any two of the second packaging film or sheet or the composite packaging material may be heat-sealed at their peripheral portions.

In still another hermetically sealed container of the present invention, one of the first or second packaging film or sheet or the composite packaging material is folded in two and the folded portion is folded in two. Except for the peripheral edges, they are heat-sealed together.

[0047]

Next, examples of the present invention will be described together with comparative examples.

Examples 1-7 and Comparative Examples 1-6 First, a list of resins used in Examples 1-7 and Comparative Examples 1-6 is shown below. (1) Amorphous polyester terephthalic acid 50mol%, ethylene glycol 35mol
%, 1,4-cyclohexanedimethanol 15 mol%, intrinsic viscosity IV = 0.75, melting point Tm = none, glass transition point Tg = 83 ° C.

(2) Amorphous polyester terephthalic acid 40 mol%, isophthalic acid 10 mol%, ethylene glycol 50 mol%, IV = 0.7
4, Tm = 220 ° C., Tg = 70 ° C. (3) Polyester elastomer, 50 mol% of terephthalic acid, 1,4-butanediol 30
mol% and polytetramethylene ether glycol (average degree of polymerization 11.5) 20 mol%, IV = 0.7
1, Tm = 170 ° C., Tg = 5 ° C.

(4) Polyester elastomer terephthalic acid 40 mol%, isophthalic acid 10 mol%,
1,4-Butanediol 15 mol%, polytetramethylene ether glycol (average degree of polymerization 13.5) 35 mol
%, IV = 0.70, Tm = 152 ° C., Tg =
Those at -40 ° C.

(5) Polyester Elastomer 50 mol% terephthalic acid, 1,4-butanediol 45
mol%, polytetramethylene ether glycol 5 mol
%, IV = 0.70, Tm = 195 ° C., Tg =
What is 45 ℃.

(6) Polybutylene terephthalate 50 mol% terephthalic acid, 1,4-butanediol 50
mol%, IV = 0.72, Tm = 223 ° C., T
g = 56 ° C.

(7) Polybutylene terephthalate 50 mol% of terephthalic acid, 50 of 1,4-butanediol
mol%, IV = 0.56, Tm = 223 ° C., T
g = 56 ° C.

(8) Ethylene-vinyl acetate copolymer having a specific gravity of 0.919, a melt index of 2.5 and a vinyl acetate content of 15%.

(9) Crystalline polypropylene having a melt index of 3.0.

Example 1 70% by weight of the amorphous polyester of the above (1) and the above (3)
A film having a thickness of 50 μm obtained by dry blending with 30% by weight of the polyester-based elastomer, and melting and film-forming with a uniaxial extruder.

Example 2 80% by weight of the amorphous polyester of the above (2) and the above (4)
20% by weight of polyester-based elastomer is melted and mixed in a Banbury mixer, and the sheet obtained by pressing is cut into pellets, which are melted by a uniaxial extruder to form a film having a thickness of 50 μm. the film.

Example 3 70% by weight of the amorphous polyester of the above (1) and the above (3)
30% by weight of the polyester elastomer is dry-blended and extruded by one uniaxial extruder, and at the same time, the other PBT is extruded by the other extruder,
Coextruded film obtained by using T-die. This film has a total thickness of 30 μm, a sealing layer of 10 μm, and a PBT layer of 20 μm.

Example 4 Using the PBT of (6) above, a film of 30 μm in thickness was formed by a uniaxial extruder and a T-die, and 80% by weight of the amorphous polyester of (2) above was formed on the film. the above
A film obtained by extrusion laminating the dry blended product of (4) with 20% by weight of the polyester elastomer to 20 μm using a uniaxial extruder. No anchor coat is used.

Example 5 Biaxially stretched polyethylene terephthalate film 12 μm
And an aluminum foil of 9 μm are pasted together by ordinary dry lamination, and the aluminum surface thereof and the PBT side of the film of Example 3 are pasted together by similar dry lamination to obtain a composite packaging material.

Example 6 A composite packaging material obtained by laminating 15 μm of a biaxially stretched polyamide film and the PBT surface of the film of Example 4 by ordinary dry lamination.

Example 7 50 mol% of terephthalic acid and 50 mol of ethylene glycol
%, An intrinsic viscosity IV = 0.70, a Tg = 75 ° C., and an amorphous polyethylene terephthalate film having a thickness of 250 μm and having a layer of PBT of 10 μm.
And a layer 10 μm comprising a mixture of 80% by weight of the amorphous polyester of the above (1) and 20% by weight of the polyester elastomer of the above (4) are obtained by coextrusion laminating so that PBT serves as an intermediate layer. Composite packaging material.
No anchor coat is applied. Comparative Example 1 95% by weight of the amorphous polyester of the above (1) and the above (3)
A film having a thickness of 50 μm obtained by dry blending 5% by weight of the polyester-based elastomer of, and melting and film-forming with a uniaxial extruder.

Comparative Example 2 80% by weight of the ethylene-vinyl acetate copolymer of the above (8)
A film having a thickness of 50 μm obtained by dry-blending 20% by weight of the crystalline polypropylene of (9) above, and melting and film-forming with a uniaxial extruder.

Comparative Example 3 10 μm of the amorphous polyester of (1) above and P of (6) above
A coextrusion film made of BT 20 μm.

Comparative Example 4 95% by weight of the amorphous polyester of (2) above was dry-blended with 5% by weight of the polyester-based elastomer of (4) above, and was added onto 30 μm of the PBT film of (6) above.
A film obtained by extrusion lamination to have a thickness of 20 μm and a total thickness of 50 μm.

Comparative Example 5 Biaxially stretched polyethylene terephthalate film 12 μm
And an aluminum foil of 9 μm were attached by ordinary dry lamination to obtain a laminated film. Further, 70% by weight of the amorphous polyester of the above (1) and 30% by weight of the polyester elastomer of the above (5) are dry-blended, and this is extruded by one uniaxial extruder, and at the same time, another one is extruded. Extrude the PBT (6) above with an extruder and
Using die, total thickness 30μm, sealing layer 10μm, PBT
A coextruded film with a layer thickness of 20 μm was obtained. Then, on the aluminum surface of the laminate film, PB of the coextrusion film
A composite packaging material in which the T side is laminated by dry lamination.

Comparative Example 6 80% by weight of the ethylene-vinyl acetate copolymer of the above (8)
And 20% by weight of the crystalline polypropylene of the above (9) were dry blended, and this was anchor-coated
(6) PBT on the film with a thickness of 30μm 20
A film obtained by extrusion laminating.

Evaluation Test The following evaluation tests were carried out in order to evaluate the heat-sealing property and easy peeling property of each sample of Examples 1 to 7 and Comparative Examples 1 to 6.

Appropriate temperature for heat sealing As a mating base material (adherend), 50 mol% of terephthalic acid and 50 mol% of ethylene glycol are used, and an intrinsic viscosity IV =
Maximum peeling is obtained when heat-sealing is carried out at a pressure of 2 kg / cm ² for 1 second using an amorphous polyethylene terephthalate (A-PET) sheet of 0.67, Tg = 77 ° C. and a thickness of 250 μm. A temperature range of 70% or more of the strength and below the temperature at which the film or the composite packaging material or a part thereof breaks.

Heat seal strength Heat seal strength in the above temperature range, peel strength when a heat seal piece having a width of 15 mm is peeled by a 180 mm peel test at 300 mm / min.

Destruction type When performing the above peel test, it is distinguished whether the seal portion peels or breaks. Cohesive failure = a state in which the seal layer itself causes layer cracks, and the seal layer remains uniformly on both of the peeled pieces.

Interfacial destruction = A state in which the seal layer unilaterally remains on one side of the peeling piece.

Partial rupture = a state in which the seal layer or the packaging material is partly ruptured.

Edge break = A state in which a heat-sealed corner of one side breaks at a time.

Peeling feeling At the center temperature of the heat seal suitable temperature, the pressure is 2 kg /
The A-PET sheet was heat-sealed at cm 2 for 1 second, the heat-sealed piece was cut into a width of 15 mm, and the peeling feeling when peeled by hand was sensory evaluated.

◯: The entire sealed portion can be uniformly peeled with an appropriate weight.

Δ: Peelable but too heavy Impractical peelability such as dirty after peeling x ... Heat sealing is not performed, and peeling can be performed without resistance. Or it is heat-sealed but cannot be peeled off.

The results of Examples 1 to 7 are shown in Table 1, and the results of Comparative Examples 1 to 6 are shown in Table 2.

[0079]

[Table 1]

[Table 2] Examples 8 to 11 and Comparative Example 7 A laminated film having a thickness of 50 μm having a sealing layer having a thickness of 15 μm and a PBT layer having a thickness of 35 μm was obtained by a coextrusion method. The sealing layer is composed of 50 mol% terephthalic acid, 35 mol% ethylene glycol, and 15 mol% 1,4-cyclohexanedimethanol, and IV = 0.75, Tm = none, Tg = 83 ° C. is added to the amorphous polyester resin, and terephthalate is added. Acid 10 mol%, 1,4-butanediol 10mo
% of polytetramethylene glycol, IV = 0.70, Tm = 155 ° C., Tg = −60 ° C.
The polyester-based elastomer is mixed at the ratio shown in Table 3. PBT layer is terephthalic acid 5
It consists of 0 mol%, 50 mol% of 1,4-butanediol and PBT with IV = 0.72, Tm = 223 ° C. and Tg = 56 ° C.

Evaluation Test The laminate film was composed of 50 mol% terephthalic acid and 50 mol% ethylene glycol, and had an intrinsic viscosity IV = 0.
67, Tg = 77 ° C. and a thickness of 300 μm of an amorphous polyester (A-PET) sheet at a sealing temperature of 180.
Heat peeling was performed at a temperature of 2.0 ° C. and a pressure of 2.0 kg / cm ^{2 for} 2 seconds, the peel strength was measured at 300 mm / min and a peel of 90 degrees, and the peeling behavior was observed. The results are also summarized in Table 3.

[0081]

[Table 3] As is clear from the results of Table 3, when the number of blended parts of the polyester-based elastomer in the seal layer is less than 10 parts by weight, the film is cut at the heat-sealed part and the peeling property is not easily achieved.

Examples 12 to 13 and Comparative Example 8 Thickness 25 consisting of a single layer of the easily peelable heat-sealing resin composition.
A μm packaging film was obtained by the T-die extrusion method. As an easily peelable resin composition for heat sealing, terephthalic acid 50 mol
%, Ethylene glycol 35 mol%, 1,4-cyclohexanedimethanol 15 mol%, intrinsic viscosity IV
= 0.75, melting point Tm = none, glass transition point Tg = 83
℃ is 100 parts by weight of the amorphous polyester resin,
As shown in Table 4, a mixture of 50 parts by weight of three types of polyester elastomers having different Tg was used. The polyester elastomer used in Example 12 was 10 mol% terephthalic acid and 10 mol 1,4-butanediol.
%, Polytetramethylene glycol 80 mol%, IV = 0.70, Tm = 155 ° C. The polyester elastomer used in Example 13 was 40 mol% terephthalic acid, 10 mol% isophthalic acid, 1,4
-Butanediol 15 mol%, polytetramethylene ether glycol (average degree of polymerization 13.5) 35 mol%, IV = 0.70, Tm = 152 ° C,
The polyester elastomer used in Comparative Example 8 was 50 mol% of terephthalic acid and 45 mol of 1,4-butanediol.
%, Polytetramethylene ether glycol 5 mol%, IV = 0.70, Tm = 195 ° C. Then, this film and a biaxially stretched polyamide film having a thickness of 25 μm were laminated by a dry lamination method using a urethane adhesive to obtain a transparent lid material.

Evaluation Test First, the haze value of the packaging film was examined by ASTM D1003. The packaging film comprises 50 mol% of terephthalic acid and 50 mol% of ethylene glycol, IV = 0.79, Tg = 73 ° C., and a thickness of 300 μm.
m amorphous polyethylene terephthalate (A-PET)
The sheet was heat-sealed under a pressure of 2.0 kg / cm ² × 2 seconds while changing the sealing temperature in the range of 15 to 200 ° C., and its peel strength was measured at a peeling speed of 300 mm / min and a peel of 90 degrees. The results are also summarized in Table 4.

[0084]

[Table 4] In Table 4, ** indicates that the film was cut at the heat-sealed portion. Further, the peel strengths A to F have heat seal temperatures of 150 ° C., 160 ° C., 170 ° C., and 18 ° C., respectively.
Indicates 0 ° C, 190 ° C and 200 ° C.

As is clear from the above results, the haze value is 5
% Or less, the transparent lid material is cut at the heat seal part.

Example 14 50 mol% of terephthalic acid, 50 mol of ethylene glycol
%, An amorphous polyester sheet (A-PET sheet) having a thickness of 500 μm and having IV = 0.67 and Tg = 77 ° C., and having a flange in the opening of 50 mm in length and 50 mm in width by a vacuum forming method. A container body having a depth of 30 mm was molded. 70 ml of mineral water was put into this container body, and the lid member of Example 8 was heat-sealed at 180 ° C. and sealed.

Example 15 and Comparative Example 9 A CPP sheet having a thickness of 400 μm was coated with 50 mol of terephthalic acid.
1%, ethylene glycol 35 mol%, 1,4-cyclohexanedimethanol 15 mol%, intrinsic viscosity I
V = 0.75, melting point Tm = none, glass transition point Tg = 8
A 80 μm thick amorphous polyester film at 3 ° C. was dry-laminated with a urethane adhesive to obtain a laminated sheet. From this sheet, a container body having the same size as that of Example 14 was formed by vacuum pressure forming using the amorphous polyester film surface as the inner surface. 70 ml of mineral water was put into this container body, and Example 10 and Comparative Example 7
The lid material was heat-sealed at 180 ° C. and sealed.

Comparative Example 10 A container body having the same size as in Example 14 was obtained from a 500 μm PP filler sheet by vacuum pressure molding. 70 ml of mineral water was put in this container body. And
A thickness obtained by dry blending a biaxially stretched polyamide film having a thickness of 15 μm, 10% by weight of an ethylene-vinyl acetate copolymer and 90% by weight of a crystalline propylene resin, and melting and film-forming with a uniaxial extruder. A lid member consisting of a 40 μm film was heat-sealed at 180 ° C. and sealed.

Evaluation test The sealed containers of Examples 14 to 15 and Comparative Examples 9 to 10 were
After being stored in an oven at 40 ° C. for 3 weeks, the sealing property was evaluated, the peel strength of the lid material was measured in the same manner as in Example 12, and further, a sensory evaluation was performed on the peel property and the change in the taste of mineral water. did. The results are summarized in Table 5.

[0090]

[Table 5] Sensory test: Tested by 10 panelists and ranked as follows.

Peeling behavior A: Peeling is smooth and the container flange after peeling is clean.

B: Peeling is a little heavy, but the container flange after peeling is clean.

C: Peeling is a little heavy, and the residue on the container flange after peeling is a concern.

D: Peeling cannot be done smoothly, and the container flange after peeling is messy.

(There is also breakage of the lid material film) Mineral water taste test A: No change in taste B: No change in taste.

C: Something strange.

D: The resin smells and there is a clear change in taste.

Examples 16 to 21 and Comparative Examples 11 to 1
4 First, a list of resins used in Examples 16 to 21 and Comparative Examples 11 to 14 is shown below. Note that (1) and (4) are the same as those described in the examples.

(1) Low crystalline polyester terephthalic acid 50 mol%, ethylene glycol 35 mol
%, 1,4-cyclohexanedimethanol 15 mol%, intrinsic viscosity IV = 0.75, glass transition point Tg =
What is 83 ℃.

(2) Styrenic thermoplastic elastomer: A styrene-ethylene / butylene block copolymer having a styrene content of 30% and saturated by hydrogenation as a main component, and having MFR = 0.5.

(3) Styrenic thermoplastic elastomer: A styrene-ethylene / butylene block copolymer having a styrene content of 10% and saturated by hydrogenation as a main component, and having MFR = 8.0.

(4) Polyester type elastomer 40 mol% terephthalic acid, 10 mol% isophthalic acid,
1,4-Butanediol 15 mol%, polyhexamethylene ether glycol (average degree of polymerization 13.5) 35 mol
%, IV = 0.70, Tm = 152 ° C., Tg =
Those at -40 ° C.

(5) Polybutylene terephthalate 50 mol% of terephthalic acid, 50 of 1,4-butanediol
mol%, IV = 0.56, Tm = 223 ° C., T
g = 56 ° C.

Example 16 80% by weight of the low crystalline polyester of the above (1) and the above (2)
10 μm of a sealing layer made of 20% by weight of the styrene-based thermoplastic elastomer and 20 μm of a layer made of (5) PBT described above.
A film formed by laminating m and m.

Example 17 70% by weight of the low crystalline polyester of the above (1) and the above (3)
25 μm of a sealing layer made of 30% by weight of the styrene-based thermoplastic elastomer and a layer 25 made of PBT of (5) above.
A film formed by laminating with μm.

Example 18 80% by weight of the low crystalline polyester of the above (1) and the above (3)
And 10% by weight of the styrene-based thermoplastic elastomer of
(4) 10% by weight of thermoplastic polyester elastomer
A film obtained by laminating a seal layer (6 μm) composed of (4) and a layer (24 μm) composed of PBT of (5) above.

Comparative Example 11 30% by weight of the low crystalline polyester of the above (1) and the above (2)
10 μm of a sealing layer made of 70% by weight of the styrene-based thermoplastic elastomer and a layer 20 made of PBT of the above (5)
A film formed by laminating with μm.

Comparative Example 12 A stretched nylon film of 15 μm and a layer of PBT of the above (5) 25 μm were dry laminated, and a sealing layer 10 of the low crystalline polyester of the above (1) was formed on the PBT surface.
A film formed by stacking μm layers.

Evaluation test The sealing surfaces of the films of Examples 16 to 18 and Comparative Examples 11 and 12 were pressured at 2 kg at each temperature of 140 to 180 ° C.
Heat-sealing was performed at / m 2 for 1 second, and the heat-sealing piece was cut into a width of 15 mm to obtain a test piece. Then, the following tests were conducted in order to evaluate the heat sealing property (heat sealing strength) and peeling peelability of each film.

Measurement of Heat Seal Strength Each test piece was subjected to a peeling test at a peeling speed of 300 mm / min and an angle of 90 degrees, and the peeling strength at that time was measured.

Destruction Type When the peeling test was performed, the peeled state and the broken state of the seal portion were observed.

The results of the evaluation test are shown in Table 6. Table 6
In the above, cohesive failure means that the seal layer itself undergoes layer cracking, and the seal layer remains uniformly on both of the peeling pieces, and interface failure means that the seal layer remains unilaterally on one side of the peeling piece, and partial breakage. Indicates a state in which the seal layer or film is partially broken, and edge break refers to a state in which the seal layer or film is broken at a corner of one side heat-sealed at one time.

[0113]

[Table 6] Furthermore, other Examples 19 to 21 of the present invention and Comparative Example 13,
14 will be described. Example 19 A stretched nylon film (25 μm) and a PBT layer (20 μm) were dry-laminated, and a sealing layer (10 μm) comprising 80% by weight of the low crystalline polyester (1) and 20% by weight of the styrene thermoplastic elastomer (2) on the PBT surface. Is laminated and heat-sealed to an A-PET sheet having a thickness of 300 μm.

Example 20 A stretched nylon film (25 μm) and a PBT layer (20 μm) were dry-laminated, and a seal composed of 50% by weight of the above (1) low crystalline polyester and 50% by weight of the above (2) styrene thermoplastic elastomer was dry-laminated on the PBT surface. Stacking 10 μm layers,
A composite packaging material obtained by heat sealing this to an A-PET sheet of 300 μm.

Example 21 9 μm of aluminum foil and 10 μm of PBT layer were dry-laminated, and the above (1) low crystalline polyester 40 was applied to the PBT surface.
% By weight and the above-mentioned (3) styrene-based thermoplastic elastomer 3
A composite packaging material obtained by stacking 10 μm of a sealing layer consisting of 0% by weight and 30% by weight of the thermoplastic polyester elastomer of (4) above, and heat-sealing this on an A-PET sheet 300 μm.

Comparative Example 13 A composite obtained by dry laminating 25 μm of a stretched nylon film and 20 μm of PBT, laminating 10 μm of the above (1) low crystalline polyester layer on the PBT surface in the same manner, and heat-sealing this to an A-PET sheet of 300 μm. Packaging material.

Comparative Example 14 A composite obtained by dry laminating 25 μm of a stretched nylon film and 20 μm of PBT, laminating 10 μm of the above (1) low crystalline polyester layer on the PBT surface in the same manner, and heat-sealing this to an A-PET sheet of 300 μm. Packaging material.

Evaluation Tests The following evaluation tests were performed on the above Examples 19 to 21 and Comparative Examples 13 and 14.

Examples 19 to 21 and Comparative Example 13,
14 packaging materials, 50 mol% terephthalic acid and 50 mol% ethylene glycol, IV = 0.67, T
A sheet of A = PET having a thickness of g = 77 ° C. and a thickness of 300 μm was heat-sealed at a heat-sealing temperature of 160 ° C. and 180 ° C. under a pressure of 2 kg / m 2 for 2 seconds, and a test piece cut into a width of 15 mm was cut. It was prepared and a peeling test was conducted at a peeling speed of 300 mm / min and an angle of 90 degrees. The peeling strength at that time was measured, and the peeling behavior was observed.

The results are shown in Table 7.

[0121]

[Table 7] Further, the following sensory evaluations were performed on the above Examples 19 to 21 and Comparative Examples 13 and 14.

A 500 μm A-PET sheet has an annular edge (1) with a width of 5 mm on the periphery of the upper opening as shown in FIG. 1, a depth (D) of 30 mm and an upper opening diameter (L) of 80 mm.
Water was placed in the transparent circular container (2) of Example 1 and the water was added to it.
Using the lid material (C) made of each of the packaging materials of 9 to 21 and Comparative Examples 13 and 14, the opening of the circular container was heat-sealed for 1 second at 170 ° C. and an air pressure of 4 kg / m 2 to hermetically seal. did. Then, five samples each were prepared, and a sensory evaluation was performed on the feeling of opening when the lid material was peeled off by five panelists. The above results are shown in Table 8.

[0123]

[Table 8]

[0124]

As described above, according to the present invention, it has a sealing property that can withstand practical use over time, and can be easily opened without damaging the packaging material at the time of opening. In addition, it is possible to provide a packaging form having transparency, hygiene, aroma retaining property, non-adsorption property, and non-polluting property which is characteristic of the polyester material.

[0125] Further, at the time of opening, a knife or the like is not used, the opening can be easily performed by hand, and the packaging material can be easily peeled off without breaking. Furthermore, the unsealed surface is beautiful because the heat-sealing layer causes uniform condensation and destruction at the time of unsealing.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a circular container.

[Explanation of symbols]

 (1) Annular edge (2) Circular container (C) Cover material (D) Container depth (L) Container opening diameter

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B32B 29/00 7016-4F B65D 65/40 E 9028-3E C08J 5/18 CFD 9267-4F C08L 53/00 LLZ 7142-4J

Claims (11)

[Claims] 1. An amorphous or low crystalline polyester 10
An easily peelable resin composition for heat sealing, which comprises 10 to 200 parts by weight of a polyester elastomer having a glass transition point of 10 ° C. or less with respect to 0 parts by weight. 2. Amorphous or low crystalline polyester 10
0 parts by weight, 5 to 100 parts by weight of a styrene-based thermoplastic elastomer containing a hydrogenated SBS copolymer as a component, and a polyester-based elastomer having a glass transition point of 10 ° C. or less 0 to
An easily peelable heat-sealing resin composition containing 100 parts by weight of the above-mentioned three components or two components. 3. The amorphous or low crystalline polyester is
An easily peelable heat seal according to claim 1 or 2, which is one polyester composed of one or more glycols and one or more dicarboxylic acids or dialkyl esters thereof, or a mixture of two or more such polyesters. Resin composition. 4. A polyester-based elastomer comprising a hard segment comprising at least one glycol and at least one dicarboxylic acid or a dialkyl ester thereof, and 1
The easy peeling according to claim 1 or 2, which is a copolymer with a soft segment comprising one or more dicarboxylic acids and one or more poly (alkylene oxide) glycols, or a mixture of two or more such copolymers. Heat-sealing resin composition. 5. A packaging film or sheet comprising the easily peelable heat-sealing resin composition according to claim 1. 6. A packaging film or sheet comprising the easily peelable heat-sealing resin composition layer according to claim 1 or 2, and a polyester resin layer laminated on one surface of the layer. 7. A composite packaging material in which at least one of a plastic film, a metal foil and paper is laminated on one surface of the packaging film or sheet according to claim 5 or 6. 8. A hermetically sealed container in which a container body made of a polyester resin is heat-sealed with a packaging film or sheet according to claim 5 or 6, or a composite packaging material according to claim 7. 9. The container body comprises a single amorphous or low crystalline polyester sheet, or a laminated synthetic resin sheet constituted by an amorphous or low crystalline polyester resin layer as the innermost layer. Sealed container. 10. A sealed container obtained by heat-sealing the peripheral portions of two packaging films or sheets according to claim 5 or 6, or two composite packaging materials according to claim 7. 11. The packaging film or sheet according to claim 5 or 6, or the composite packaging material according to claim 7, each one being folded in two, and peripheral edges other than the folds are heat-sealed. A sealed container.