JPH06287417A - Pet-based resin composition, film and laminate - Google Patents

Abstract

PURPOSE:To provide the subject composition to be used for producing readily unsealable PET-based films (and laminates thereof) excellent in fragrance retentivity and oil resistance useful for e.g. closures for PET-based containers. CONSTITUTION:The objective PET-based resin composition comprising (A) 50-90 pts.wt. of a PET-based resin, (B) 2-30 pts.wt. of PET-based resin, (C) 5-30 pts.wt. of a styrene-based resin and (D) 3-25 pts.wt. of an acid-modified olefin resin, making a total of 100 pts.wt.. The other objective films and laminates can be obtained from this resin composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easy-open PET film excellent in aroma retention and oil resistance used for a lid material of a polyethylene terephthalate container and a PET system used for producing a laminate thereof. It relates to a resin composition.

[0002]

2. Description of the Related Art Conventionally, as a PET-based resin composition used for a polyethylene terephthalate-based lid material having an easy-open property, Japanese Patent Publication No. 3-50706 discloses a saturated polyester-based resin and a polyethylene resin in a fixed ratio. A resin composition prepared by blending the above is disclosed.

However, when a lid material made of this resin composition is used, the sealing temperature range for easy opening is wide, but since the polyethylene content of the seal layer is large, the seal layer undergoes cohesive failure when the lid material is peeled off. And a part of the sealing layer remains on the container, which is not preferable in appearance.

[0004]

DISCLOSURE OF THE INVENTION The present invention is suitable for a cover material of a polyethylene terephthalate type container, etc., and has a wide sealing temperature range of a sealing layer, does not cause cohesive failure at the time of opening, and is excellent in aroma retention and oil resistance. Another object of the present invention is to provide a PET-based resin composition used for producing an easily-openable PET-based film and a laminate thereof.

The inventors of the present invention have used a wide range of easy-opening sealing temperature range, a cohesive failure at the time of opening, excellent aroma retention and oil resistance, and a resin used for producing a laminate thereof and the like. As a result of earnestly studying the composition,
A PET resin composition containing (A) polyethylene terephthalate resin, (B) polybutylene terephthalate resin, (C) styrene resin and (D) acid-modified olefin resin in a specific compounding ratio was found. The present invention has been completed.

[0006]

That is, the present invention provides (A) polyethylene terephthalate resin 50 to 90 parts by weight, and (B) polybutylene terephthalate resin 2-3.
0 parts by weight, 5 to 30 parts by weight of (C) styrene resin and 3 to 25 parts by weight of (D) acid-modified olefin resin,
The total amount of each component of (A), (B), (C) and (D) is 1
A PET-based resin composition, characterized in that the content of the resin composition is 00 parts by weight.
An ET film and a laminate in which the film is laminated on at least one surface of a base film.

The (A) polyethylene terephthalate resin of the present invention comprises phthalic acid, isophthalic acid, terephthalic acid,
Saturated polybasic acids such as maleic acid, maleic acid derivatives, succinic acid, adipic acid and sebastic acid, and ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, 1,2-propylene glycol, 1,3-butanediol, dipropylene glycol, 1 Polyethylene terephthalate resin obtained by ester bond with polyhydric alcohol such as 1,4 butanediol and 1,4 cyclohexanedimethanol. Specifically, when the total amount of the monomers of the polyethylene terephthalate resin is 100 mol%, terephthalic acid 30 is used as the acid component monomer.
It is preferable that the amount of the monomer is not less than mol%, not less than 30 mol% of ethylene glycol as a monomer of the glycol component, and not more than 5 to less than 20 mol% of 1,4-cyclohexanedimethanol.

The polybutylene terephthalate resin (B) of the present invention contains 30 mol% or more of terephthalic acid as an acid component and 1,4-butanediol as a glycol component, respectively, when the total amount of monomers is 100 mol%. As long as it is a copolymer, a copolymer of other comonomer components can also be used. Specific examples of the comonomer of the acid component include isophthalic acid, sebacic acid, adipic acid and azelaic acid, and examples of the comonomer of the glycol component include ethylene glycol, diethylene glycol, neopentyl glycol and 1,4-cyclohexanedimethanol. I can list things. Specifically, those consisting only of terephthalic acid and 1,4-butanediol are particularly preferable because they have a wide sealing temperature range of easy opening when used as a lid material or the like.

The styrene resin (C) of the present invention includes
Polystyrene, acrylonitrile-styrene copolymer (AS resin), methyl methacrylate-styrene copolymer (MS resin), styrene-butadiene-styrene block copolymer, acrylonitrile-butadiene-styrene copolymer (ABS resin), methacryl Examples thereof include acid methyl-butadiene-styrene copolymer (MBS resin). The AS resin is particularly preferable because it has a wide processability range when it is heated and mixed into a resin composition and has a wide seal temperature range of easy opening. The styrene-based resin has good suitability for heating and mixing with other resins constituting the resin composition, and these are not limited to one type, and a mixture of two or more types can also be used.

Examples of the acid-modified olefin resin (D) of the present invention include olefin resins having a carboxylic acid-derived polar group in the main chain or side chain. In the case of the present invention, one or more of these may be used.
As the acid-modified olefin resin having a carboxylic acid-derived polar group, specifically, polyolefin modified with maleic acid, for example, polyethylene modified with maleic acid, ethylene-vinyl acetate copolymer and saponified product thereof. Examples thereof include those modified with maleic acid, and those obtained by grafting a polymer containing an acid in the side chain onto polyolefin. Among the acid-modified olefin resins, those obtained by modifying polyethylene with maleic acid are particularly preferable in consideration of thermal stability during melt-kneading.

The compounding ratio of each resin of the present invention is 50 to 90 parts by weight of the component (A), 2 to 30 parts by weight of the component (B), and the component (C) when the total amount of the resin composition is 100 parts by weight. 5-30
Parts by weight and 3 to 25 parts by weight of the component (D). When the compounding ratio of the resin (A) is less than 50 parts by weight, the easy-opening property with respect to an adherend such as a polyethylene terephthalate-based container and oil resistance and aroma retention cannot be obtained, and when it exceeds 90 parts by weight, the easy-opening property is improved. It is not preferable because the sealing temperature range of the property becomes narrow. If the compounding ratio of (B) is less than 2 parts by weight, the easy-open property is lost during high temperature sealing, and if it exceeds 30 parts by weight,
It is not preferable because it does not adhere at the time of low temperature sealing. (C)
If the compounding ratio is less than 5 parts by weight, the easy-open property does not appear,
If it exceeds 30 parts by weight, the adhesion to the adherend and oil resistance
It is not preferable because the ability to retain aroma is lowered. If the compounding ratio of (D) is less than 3 parts by weight, it will not adhere during low temperature sealing,
If it exceeds 25 parts by weight, the ease of opening at the time of high temperature sealing is lost, which is not preferable.

The present invention includes the above resins (A), (B),
(C) and (D) are heated and melt mixed to form a resin composition, and if necessary, additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a lubricant and a pigment are added. be able to.

Various existing methods can be used as a method for producing a film and a laminate having an easy-opening property by using the PET resin composition of the present invention. Specifically, among the raw material resins, those that hydrolyze or foam when heated in a hygroscopic state are previously dried to a level at which they do not decompose or foam, and then mixed by a dry blending method at a specific mixing ratio, or extruded. A method may be mentioned in which a pellet is formed with a machine, dried, and then fed to an extruder equipped with a T die or an inflation die at its tip to form a film. In addition, a method of forming a laminated film by coextrusion with another resin at the time of manufacturing the film is also exemplified. The film thus obtained can be used as a cover material or the like for a polyethylene terephthalate container as it is or by laminating it with another substrate film by a method such as dry lamination or extrusion lamination. Further, it can be coated on another substrate film or a sheet-like material to form a lid material or the like. As the base film, general films such as polyethylene terephthalate film, polypropylene film, nylon film, polyethylene film, and polystyrene film are used.

[0014]

[Examples] Intrinsic viscosity (IV) in this example means that the measurement resin is phenol / tetrachloroethane (weight ratio: 5).
0/50) mixed solution with a solution concentration of 0.5 g / 1
The viscosity was adjusted to 0 ml and the viscosity measured using an Ubbelohde viscometer in a constant temperature bath at 30 ° C is shown. Further, the MI value in Examples and Comparative Examples indicates the fluidity under 200 ° C. and a load of 5 kg (the weight that fluidized per 10 minutes). However, in the case of a polybutylene terephthalate resin, 23
Measured value under the conditions of 5 ° C and load of 2.6 kgf, 190 ° C in case of acid-modified olefin resin, load of 2.16 kgf
The measured values under the conditions of are shown.

Examples 1 to 7 Polyethylene terephthalate (Tg = 81 ° C., IV = 0.75) comprising 50 mol% of terephthalic acid, 35 mol% of ethylene glycol and 15 mol% of 1,4-cyclohexanedimethanol as resin (A) , Abbreviated as PET-1 hereinafter), 40 mol% of terephthalic acid, 10 mol% of isophthalic acid and 50 mol% of ethylene glycol (Tg = 64 ° C., IV = 0.72,
Hereinafter, abbreviated as PET-2), polyethylene terephthalate composed of terephthalic acid and ethylene glycol (IV =
0.84, hereinafter abbreviated as PET-3) was used. Polybutylene terephthalate composed of terephthalic acid and 1,4-butanediol as the resin (B) (IV = 1, hereinafter P
BT-1), 45 mol% terephthalic acid, 5 mol% isophthalic acid and 50 mol% 1,4-butanediol (IV = 1, hereinafter P
BT-2) was used. As the resin (C), AS resin (trade name: Denka AS resin AS-SF, acrylonitrile-styrene copolymer, MI = 0.3, hereinafter abbreviated as AS) and polystyrene (trade name: Denkastyrol GP,
MI = 6, hereinafter abbreviated as PS) and MS resin (trade name: Denka TX polymer, methyl methacrylate-styrene copolymer, MI = 2, hereinafter abbreviated as MS) were used.

As the resin (D), a maleic acid-modified polyethylene resin having MI = 1, Admer S manufactured by Mitsui Petrochemical Co., Ltd.
F700 was used. The respective resins described above were mixed by a dry blending method. 40mmφ extruder (L / D =
No. 32, with dull image) was heated and melt-kneaded at a processing temperature of 240 ° C. to prepare pellets of the resin composition. After drying the pellets at 70 ° C. for 5 hours in a dehumidifying dryer, they are extruded at a processing temperature of 240 ° C. by a 40 mmφ extruder (L / D = 28) equipped with a coat hanger die at the tip, and then are cooled by a cooling roll. After cooling, a film having a thickness of 20 μ was prepared. Further, one side of the obtained film was subjected to corona treatment, and after applying 5 μ of a polyurethane adhesive, a base film of 12 μ in thickness and biaxially oriented polyethylene terephthalate film (O-PET) were formed by a dry laminating method. The pieces were pasted together to finally obtain a laminated film having a total thickness of 37 μm. Performance evaluation was performed for each. Table 1
The resin composition and the evaluation result of each example are shown in FIG. The resin composition is shown in parts by weight.

Comparative Example 1 Using PET-1 as the resin (A), PBT-1 as the resin (B), the AS resin as the resin (C) and the Admer SF700 as the resin (D), Example 1
Create a 20μ film in the same manner as in
O-PET and dry laminate for total thickness 3
A 7μ laminated film was obtained. The same evaluation as in the example was performed. Table 1 shows the evaluation results. Comparative Example 2 Ethylene-vinyl acetate resin composition (manufactured by Hirodyne Co.,
Product name: Hot melt adhesive 7560, specific gravity = 0.93
PET with a thickness of 25μ biaxially stretched
The film was extrusion-laminated at a processing temperature of 200 ° C. using a 40 mmφ extruder (L / D = 28) to form an adhesive film having a total thickness of 37 μm. The same evaluation as that of the above-mentioned example was performed. Table 1 shows the evaluation results. In addition, various evaluations of Examples and Comparative Examples were performed by the following methods.

(Peeling Strength Evaluation Method) The resin composition surface (seal side) of the laminate film and the adherend sheet (thickness: 0.
5 mm non-crystalline polyethylene terephthalate resin sheet) and sealing pressure (seal head surface pressure) 10 kg
/ Cm ² , sealing time 1 second, heat seal temperature 12
Heat sealing was performed with a wide range of changes from 0 ° C to 200 ° C. After heat-sealing, cut into strips with a width of 15 mm,
The sheet and the film were fixed to a tensile tester so that the peeling angle was 180 °, and the sheet and the laminated film were peeled off at a tensile speed of 200 mm / min. The strength at this time was defined as the peel strength. The unit of peel strength is g / 15 mm. The range of peel strength showing easy opening property is 300 to 3000 g / 1.
It is 5 mm. In addition, if the laminate film is broken during this tensile peel test, the material is broken, and if the laminate film and the sheet do not adhere, the strength cannot be detected.
The case where the seal layer remains on the adherend sheet is regarded as aggregation.

(Oil resistance evaluation method) A resin composition surface (sealing surface) of a laminate film was placed on a smooth stainless plate with its inner surface having an inner diameter of 110 mm / opened at both ends.
Place a hollow cylinder with a height of 35 mm, and pour 300 ml of n-heptane as a substance similar to the oil component into this cylinder.
It was left at 5 ° C for 1 hr. After 1 hr, n- in the cylinder
The heptane was transferred to an evaporator and removed to about 5 ml, and then transferred to an evaporation dish of known weight and evaporated to dryness. The difference between the weight of the evaporating dish before n-heptane transfer and the weight after n-heptane transfer was divided by 300 ml of n-heptane used to calculate the elution concentration of n-heptane. The unit of elution concentration is pp
Indicated by m. If the elution concentration is less than 10 ppm,
Judged as having good oil resistance.

(Method of evaluating aroma retention) In a non-crystalline polyethylene terephthalate container having a height of 60 mm, an opening lengthwise and widthwise length of 66 mm, and an internal volume of 190 ml, d is used as an aroma component.
-Into a cylindrical glass bottle having an opening with an inner diameter of 10 mm containing 2 ml of limonene, and sealing pressure (sealing head surface pressure) 10 kg / c between the container and the laminate film.
Heat sealing was performed at m ^{2 for} a sealing time of 1 second and a heat sealing temperature of 180 ° C. The container sealed by this heat sealing is left for 72 hours in a thermostatic chamber at 23 ° C., d-limonene is evaporated into a polyethylene terephthalate container and adsorbed on a laminate film. After a lapse of a predetermined time, the laminated film was peeled off, 32 cm ² of the film adsorbing d-limonene was cut out, and the cut out film was dipped in 20 ml of ethyl acetate to extract d-limonene.
The amount of d-limonene extracted with ethyl acetate was quantified by gas chromatography (FID detection, glass column, carrier gas: He). The obtained numerical value was divided by the film area to finally obtain the adsorbed amount of d-limonene per unit area. Fragrance retention unit is ng (10 ^-9 g) /
It is shown in cm ² . The amount of adsorbed d-limonene is 100 ng /
Those having a scent retention of less than cm ² are judged to have good fragrance retention.

[0021]

[Table 1]

[0022]

As described above, according to the present invention, 50 to 90 parts by weight of (A) polyethylene terephthalate resin,
(B) Polybutylene terephthalate resin 2 to 30 parts by weight, (C) Styrene resin 5 to 30 parts by weight and (D) Acid-modified olefin resin 3 to 25 parts by weight, (A),
A PET resin composition, wherein the total amount of each of the components (B), (C) and (D) is 100 parts by weight,
Furthermore, it becomes possible to obtain an easily openable PET-based film made of the resin composition and a laminate in which the film is laminated on at least one side of a base film.

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Claims (3)

[Claims] 1. (A) 50 to 90 parts by weight of polyethylene terephthalate resin, (B) 2 to 30 parts by weight of polybutylene terephthalate resin, (C) 5 to 3 of styrene resin.
0 parts by weight and (D) 3 to 25 parts by weight of an acid-modified olefin resin, wherein the total amount of each of the components (A), (B), (C) and (D) is 100 parts by weight. PET
-Based resin composition. 2. An easily openable PET film comprising the resin composition according to claim 1. 3. A laminate, wherein the easily openable PET film according to claim 2 is laminated on at least one surface of a substrate film.