JPH08318606A - Multilayer packaging material and vessel - Google Patents

Abstract

PURPOSE: To improve the aroma retentivity, flexibility, pinhole resistance, or particularly heat sealability and stickiness with a base material by specifying the content of metal atom of resin composition containing copolymer polyethylene terephthalate(PETP) for constituting the innermost layer of a multilayer packaging material as a main ingredient and the crystallizing peak temperature and the cold crystallizing heat quantity at the time of temperature rising. CONSTITUTION: The resin composition containing copolymer PETP for constituting the innermost layer of a multilayer packaging material as a main ingredient contains 0.1wt.% or less of metal atom, and its thermal characteristics include 130 to 200 deg.C of crystallizing peak temperature and 14 to 50J/g of cold crystallizing heat quantity at the time of temperature rising measured by DSC. The copolymer PETP has critical viscosity measured at 30 deg.C in mixed solvent of phenol/1,1,2,2-tetrachloro-ethane (weight ratio = 1/1) of normally 0.5 to 1.5dl/g and the copolymerization ratio of the copolymer having a fatty ring/a normal chain or branched fatty chain having 3 or more carbons of 2 to 25mol%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer packaging material excellent in aroma retention, adhesiveness, impact resistance, flexibility, pinhole resistance, spreadability and the like. More specifically, it is characterized by using a polyester having excellent heat sealability and adhesiveness with a base material as an innermost layer, which is suitable for packaging contents such as foods and cosmetics in which the change of aroma components is not preferred It relates to multilayer packaging materials and containers formed therefrom.

[0002]

2. Description of the Related Art In packaging containers such as paper packs, trays and lids, cans, beverages such as juice, water, liquor, foods such as convenience foods and fruits, or fragrances, cosmetics,
The inner surface may come into direct contact with the contents such as fragrances where the change of aroma components is not preferred, and therefore the material forming the innermost layer has excellent aroma retention and gas barrier properties. Required to be present. From such a background, polyester, especially polyethylene terephthalate, is drawing attention as the innermost layer of these packaging containers. For example, hollow molded bottles and multi-layered paper packs have been widely used in the field of beverage packaging such as juice, lactic acid bacterium beverage, water and liquor, and in the field of cosmetic packaging.

For example, in a paper pack, it is necessary to laminate a heat-sealable resin layer as an innermost layer on the paper in order to perform heat-sealing in the molding and filling steps. As the heat-sealable resin layer, polyolefin, especially polyethylene, has been frequently used. Polyolefin is
Not only is it excellent in heat sealability, but it is also excellent in flexibility and has the advantage that pinholes do not occur during bending. However, polyolefin is accompanied by a resin odor and is likely to adsorb a fragrance component, which has the drawback that the taste and aroma change depending on the type of contents.

On the other hand, homopolyethylene terephthalate consisting essentially of terephthalic acid and ethylene glycol is
Although it absorbs less aroma components and has excellent gas barrier properties, it has poor impact resistance and heat sealing properties, and when it is laminated, its interlayer adhesion to the base material is low, making it the most suitable multilayer packaging material that requires heat sealing. It was difficult to use for the inner layer. Also, for example, cyclohexanedimethanol is about 30
Amorphous polyethylene terephthalate copolymerized by mol% was excellent in impact resistance but not satisfactory in aroma retention and heat resistance.

Therefore, as a method for improving the drawbacks of such a polyethylene terephthalate resin, Japanese Patent Laid-Open No.
No. 127340 discloses that the innermost layer has a crystallinity of 10%.
A method of using a layer in which a random copolymer is dispersed in a low crystalline polyester resin of less than 1 is disclosed. This method is intended to improve the impact resistance and heat sealability, which are the drawbacks of polyethylene terephthalate resin, and its aroma retention is insufficient due to its low crystallinity.

Further, there is disclosed a method of using a layer obtained by blending an ethylene / (meth) acrylic acid ester type copolymer or an ethylene copolymer ionomer with a copolymerized polyethylene terephthalate as the heat seal layer (Japanese Patent Laid-Open No. HEI 2). No. 233372, JP-A-3-3283
No. 7, JP-A-5-209116). This method is intended to improve heat sealability and flexibility, and the adhesiveness between the heat seal layer and the substrate is not always sufficient, and an ionomer resin having a large metal atom content was used. In this case, there is a problem that the heat-sealing property and the aroma retaining property are deteriorated due to the increase in the crystallization rate of the copolymerized polyethylene terephthalate and the decrease in the thermal stability.

Further, a composition comprising a polyolefin resin graft-modified with an unsaturated carboxylic acid or its anhydride and a tackifying resin is adhered to a crystalline copolymerized polyethylene terephthalate containing 3 to 20 mol% of a copolymerization component. A method of laminating as a layer is disclosed (JP-A-3-
133638 gazette, JP-A-3-297640 gazette,
JP-A-4-97841). However, the copolymerization component of the copolymerized polyethylene terephthalate used here and the crystallinity as the innermost layer are not particularly limited, and in many cases, heat sealability or interlayer adhesiveness between the innermost layer and the adhesive layer is used. Was insufficient and not satisfactory.

[0008]

DISCLOSURE OF THE INVENTION The object of the present invention is excellent in aroma retention, impact resistance, flexibility, pinhole resistance, spreadability, etc., and particularly heat sealability and adhesiveness to a substrate. Another object is to provide a multilayer packaging material having an excellent innermost layer.

[0009]

Means for Solving the Problems As a result of intensive investigations by the present inventors in view of the above problems, a multilayer packaging material containing a specific copolymerized polyethylene terephthalate and using a resin composition having specific physical properties as an innermost layer is The present invention has been achieved by finding that the above-mentioned problems are sufficiently satisfied. That is, the gist of the present invention is to copolymerize a copolymerization component having an intrinsic viscosity of 0.5 to 1.5 dl / g and having an alicyclic ring and / or a linear or branched aliphatic chain having 3 or more carbon atoms. Ratio is 2
A multilayer packaging material comprising an innermost layer made of a resin composition containing, as a main component, copolymerized polyethylene terephthalate in an amount of 25 to 25 mol% and having a metal atom content of 0. It is 1% by weight or less, and the crystallization peak temperature at the time of heating is 130 to 200 ° C., which is a multilayer packaging material.

Hereinafter, the present invention will be described in detail. The multilayer packaging material of the present invention contains a specific copolymerized polyethylene terephthalate as a main component, contains a specific amount of metal atoms, and is an innermost layer made of a resin composition having a specific crystallization temperature and a specific amount of cold crystallization heat. It is characterized by having.
The resin composition used as the innermost layer of the multilayer packaging material of the present invention contains a specific copolymerized polyethylene terephthalate as a main component.

The copolymerized polyethylene terephthalate used in the innermost layer is a copolymerized polyethylene terephthalate consisting essentially of a dicarboxylic acid and a diol and containing terephthalic acid and ethylene glycol as main repeating units. The intrinsic viscosity is usually 0.5 to 1.5 dl / g, preferably 0.5 to 1.2 dl when measured at 30 ° C. in a mixed solvent of 2,2-tetrachloroethane (weight ratio = 1/1). / G, more preferably 0.
6 to 1.0 dl / g, more preferably 0.6 to 0.8
It is in the range of dl / g. When the intrinsic viscosity is less than 0.5 dl / g, the strength of the molded article obtained by molding the obtained multilayer packaging material is low, which is not preferable. On the other hand, if the intrinsic viscosity exceeds 1.5 dl / g, it will be costly to produce the copolymerized polyethylene terephthalate, and
It is not preferable because the moldability when molding the multilayer packaging material is low.

The copolymerized polyethylene terephthalate has a copolymerization ratio of a copolymerization component having an alicyclic ring and / or a linear or branched aliphatic chain having 3 or more carbon atoms of 2 to 25.
Mol%, preferably 3 to 20 mol%, more preferably 5 to 15 mol%. The ratio of copolymerization components is 25
If it exceeds mol%, the aroma retaining property and the gas barrier property of the obtained multilayer packaging material are low, and the thermal stability is also low, which is not preferable. On the other hand, when the ratio of the copolymerization component is less than 2 mol%, the flexibility, impact resistance and heat sealability of the innermost layer of the obtained multilayer packaging material are lowered, which is not preferable. Here, the ratio of the copolymerization component is the sum of the ratio of the dicarboxylic acid component other than terephthalic acid to the total dicarboxylic acid component and the ratio of the diol component other than ethylene glycol and diethylene glycol to the total diol component.

The dicarboxylic acid component, which is a copolymerization component of copolymerized polyethylene terephthalate, includes an aliphatic ring such as 1,4-cyclohexanedicarboxylic acid, adipic acid and sebacic acid and / or a linear or branched chain having 3 or more carbon atoms. The dicarboxylic acid component having a fatty chain of Further, as the diol component, 1,4-cyclohexanedimethanol, propylene glycol, 1,
Examples of the diol component include an aliphatic ring such as 4-butanediol, neopentyl glycol and 2-butyl-2-ethyl-1,3-propanediol and / or a linear or branched aliphatic chain having 3 or more carbon atoms. To be Only 1 type may be used for these and 2 or more types may be used together. Among these copolymer components having an alicyclic ring and / or a linear or branched aliphatic chain having 3 or more carbon atoms, 1,4-cyclohexanedimethanol and 2-butyl-2-ethyl-1,3 are preferable. −
Propanediol, 1,4-butanediol, neopentyl glycol, more preferably 1,4-cyclohexanedimethanol and 2-butyl-2-ethyl-1,3-propanediol. When a copolymerization component having an alicyclic ring and / or a linear or branched aliphatic chain having 3 or more carbon atoms is used, it can be used as a base material such as a polyolefin due to a molecular structure in which the alkyl chain portion has a large occupied volume. It is preferable because it increases the adhesiveness and heat sealability of
Since it has a large effect of increasing the free volume of the copolymerized polyethylene terephthalate, it is preferable in terms of flexibility and impact resistance.

A dicarboxylic acid component or a diol component other than a component having an alicyclic ring and / or a linear or branched fatty chain having 3 or more carbon atoms should also be used as a copolymerization component within a range that does not impair the effects of the present invention. You can Specific examples include components such as isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and succinic acid. Furthermore, in the present invention, hydroxybenzoic acid, an oxycarboxylic acid component such as glycolic acid, or a trifunctional or higher functional compound such as trimellitic acid, trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, or pentaerythritol. A carboxylic acid component and a hydroxy component can also be treated and used as a dicarboxylic acid component and a diol component.
The bifunctional component other than the component having an alicyclic ring and / or a linear or branched fatty chain having 3 or more carbon atoms is usually used in an amount of 5 mol% or less, preferably 3 mol% or less. Is desirable from the viewpoint of adhesiveness, flexibility, and impact resistance, and it is desirable that the content of trifunctional or higher components is usually 1 mol% or less, preferably 0.7 mol% or less from the viewpoint of gelation prevention.

Regarding the copolymerization ratio of diethylene glycol, it is usually 5 mol% or less, preferably 4 mol% or less, more preferably 3 mol% with respect to the total diol component.
It is desirable that the content is mol% or less. When the copolymerization ratio of diethylene glycol is within this range, the multilayer packaging material obtained has high thermal stability and is more preferable.

The resin composition used as the innermost layer has a metal atom content of 0.1% by weight or less, preferably 0.08.
The content is less than or equal to wt%, more preferably less than or equal to 0.06 wt%, and even more preferably less than or equal to 0.05 wt%. Here, the metal atom refers to sodium, potassium, lithium, magnesium, calcium, zinc, cobalt, manganese, germanium, antimony, titanium, and the metal atom content is the entire resin composition constituting the innermost layer of these metal atoms. Is the sum of the weight ratios to. For measuring the metal atom content, fluorescent X-ray measurement method, atomic absorption method, emission spectroscopy method,
A conventionally known method can be used. As the copolymerized polyethylene terephthalate containing many metal atoms,
For example, copolymerized polyethylene terephthalate using many of the above metal atoms as a polymerization catalyst, copolymerized polyethylene terephthalate added with a basic compound such as potassium carbonate to suppress the production of diethylene glycol, or 5
-Copolymerized polyethylene terephthalate obtained by copolymerizing a component containing a metal atom such as sodiosulfoisophthalic acid. When the metal atom content of the resin composition used as the innermost layer is more than 0.1% by weight,
The decrease in the thermal stability of the innermost layer and the decrease in the adhesiveness due to the increase in the crystallization rate are remarkable, which is not preferable.

The resin composition used as the innermost layer has a crystallization peak and a melting peak when measured by a differential scanning calorimeter (hereinafter referred to as "DSC"). The crystallization peak and the melting peak are peaks derived from the copolymerized polyethylene terephthalate component, and the copolymerized component of the copolymerized polyethylene terephthalate, the copolymerization amount, the metal atom content, the presence or absence of additives, and the additives. If there is, it varies depending on the type and ratio.

Regarding the thermal characteristics of the resin composition used as the innermost layer, the crystallization peak temperature (hereinafter referred to as "crystallization peak temperature") at a temperature rise measured by DSC is 130.degree.
00 ° C, preferably 140 to 195 ° C, more preferably 150 to 190 ° C, further preferably 160 to 185 ° C.
Is. When the crystallization peak temperature is less than 130 ° C,
Since crystallization proceeds during heat sealing, the heat sealing strength decreases, which is not preferable. On the other hand, if the temperature exceeds 200 ° C., the aroma retaining property is insufficient, which is not preferable.

Generally, the melting peak temperature of the resin is higher than the crystallization peak temperature. In the present invention, the difference between the melting peak temperature and the crystallization peak temperature is usually 95 ° C or lower, preferably 85 ° C or lower. The smaller the temperature difference, the better the heat-sealing property of the innermost layer obtained, and the better the moldability when the resin composition is molded into a multilayer packaging material.

Further, the resin composition used as the innermost layer has a cold crystallization heat amount of 14 to 50 J / g, preferably 15 to 40 J / g, and more preferably 16 to 30 J / g.
g. Here, the cold crystallization heat amount of 14 J / g substantially corresponds to the crystallinity of 10%. If the heat of cold crystallization is less than 14 J / g, the aroma retention is insufficient, which is not preferable. If it exceeds 50 J / g, flexibility and impact resistance are insufficient, which is not preferable.

The crystallization peak temperature, the melting peak temperature and the amount of cold crystallization heat associated with crystallization are measured according to JIS-K712.
1. In accordance with JIS-K7122, the resin composition used as the innermost layer is heated from room temperature by DSC at a heating rate of 2
The measurement is performed by raising the temperature at 0 ° C./minute to 300 ° C.

The acetaldehyde content of the resin composition used as the innermost layer is usually 0.01% by weight or less, preferably 0.008% by weight or less, and more preferably 0.00% by weight or less.
It is desirable to be 5% by weight or less, and more preferably 0.003% by weight or less. Here, the acetaldehyde content is the weight ratio of acetaldehyde to the resin composition, which was extracted with hot water at 160 ° C. for 2 hours and quantified by gas chromatography. When the acetaldehyde content is within this range, the amount of acetaldehyde transferred from the innermost layer of the multilayer packaging material of the present invention to the contents is sufficiently small and no off-flavor is added to the contents, which is more preferable.

The resin composition used as the innermost layer may contain an additive other than the copolymerized polyethylene terephthalate within a range not impairing the effects of the present invention. Examples of the additives include hindered phenolic antioxidants and slip agents known by trade names such as Irganox 1010 and Irganox 1076, colorants such as titanium dioxide and talc, anti-blocking agents, and α-olefins. Examples include softeners such as copolymers and carboxylic acid anhydride modified products thereof, and impact modifiers. Of these additives,
An α-olefin copolymer and its carboxylic acid anhydride modified product are preferable, and 1-butene copolymerized polyethylene and its maleic anhydride graft modified product are most preferably used.

Next, the method for producing the multilayer packaging material of the present invention will be described in detail. First, for the production of the innermost layer of the multilayer packaging material of the present invention, the copolymerized polyethylene terephthalate used as a raw material may be one produced by a conventionally known method. Known production methods include, for example, melt polymerization, subsequent drying / crystallization steps, and further solid phase polymerization.
By using the copolymerized polyethylene terephthalate produced by solid phase polymerization, it is possible to obtain a multilayer packaging material having a lower acetaldehyde content.

When molding the multilayer packaging material of the present invention,
The innermost layer may be formed as a single layer and then adhered to the substrate by a method such as hot pressing to be formed, or the innermost layer may be extruded and laminated on the substrate as a single layer. Further, the innermost layer and the base material may be coextruded, or the innermost layer and a part of the base material may be coextruded and then adhered to the rest of the base material. An adhesive layer may be provided.

Regarding the melt-molding method of the multilayer packaging material of the present invention, melt-molding such as extrusion cast molding, press molding and co-extrusion, which are generally used conventionally for polyethylene terephthalate and polyolefins, further include extrusion inflation molding. Method can be used. When performing these melt moldings, the extrusion temperature of the innermost layer is usually 200 to 300.
C., preferably 220-280.degree. C. The thickness of each layer may be set arbitrarily, but for example, each layer may be set to a thickness of 5 to 800 μm to form a film. In addition, after extrusion, it is desirable that the innermost layer is rapidly cooled and molded by, for example, a casting roll so as not to promote crystallization of the innermost layer.

In producing the multilayer packaging material of the present invention,
The above-mentioned additives can be appropriately added within a range that does not impair the effects of the present invention. These additives may be blended at the time of melt kneading or melt molding, or may be blended in the raw material resin in advance.

The innermost layer of the multilayer packaging material of the present invention may be obtained by molding copolymerized polyethylene terephthalate alone, or may be melt-molded after the copolymerized polyethylene terephthalate and the additive are melt-kneaded in a final weight ratio in advance. Alternatively, it may be obtained by dry-blending at the final weight ratio, supplying the mixture to a molding machine, and performing melt molding. Furthermore, a resin composition (masterbatch) containing the above-mentioned additives in a ratio of not less than the final weight ratio is once produced by melt-kneading, and then it is further diluted and melt-molded to prepare a multilayer packaging material of the present invention. The inner layer can also be obtained. By performing the melt-kneading operation, the dispersibility of the additive in the innermost layer of the multilayer packaging material of the present invention can be further improved.

As the base material of the multi-layer packaging material of the present invention, other plastic materials, paper, metal foil and the like can be used alone or in combination. For example, the provision of the polyethylene layer on the base material is more preferable because the moldability in extrusion inflation molding is improved and a container having excellent dimensional stability can be provided at low cost. Further, by providing a paper layer on the base material, a container having more excellent impact resistance and dimensional stability can be provided, which is more preferable. Furthermore, by providing a metal layer of aluminum or the like on the base material, the gas barrier property is significantly improved, and it is possible to provide a container that can store foods and the like that do not like being mixed with oxygen and the like for a long period of time, which is more preferable. Further, an adhesive layer may be provided on the surface of the base material which is in contact with the innermost layer in order to easily adhere the innermost layer to the base material.

By molding the multilayer packaging material of the present invention, it can be preferably used as a packaging container for paper packs, trays and lids, cups and lids, standing pouches and the like.

When used in a paper pack, for example, two layers of an innermost layer / adhesive layer are laminated on a base material composed of an aluminum layer / polyethylene layer / paper layer / polyethylene layer, and the innermost layer /
Impact resistance is obtained by bending and heat-sealing a multi-layer packaging material having a six-layer structure of an adhesive layer / aluminum layer / polyethylene layer / paper layer / polyethylene layer.
A container having excellent dimensional stability and gas barrier properties can be obtained. For the adhesive layer, for example, polyethylene, α-olefin copolymer, or its carboxylic acid anhydride modified product may be used.

When used as a tray or a cup and a lid, the tray or the cup can be easily molded by, for example, drawing the multilayer packaging material of the present invention having a two-layer structure of the innermost layer / polyethylene layer. By controlling the crystallinity of the innermost layer or the polyethylene layer that is the base material, it is possible to obtain a molded product having excellent heat resistance and impact resistance. The lid can be used by providing a ruled line or the like on the same multi-layer packaging material, and by heat-sealing the both, a container excellent in sealing property and easy opening property can be obtained.

When used in a standing pouch, for example, the innermost layer is laminated on a base material composed of an adhesive layer / polyethylene layer, and the multi-layer packaging material of the present invention having a three-layer structure of innermost layer / adhesive layer / polyethylene layer is heat-sealed. By doing so, a retort packaging container and the like can be easily obtained, and each is more preferable.

[0034]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In this example,
"Parts" means "parts by weight".

Various test methods used in this example are shown below. The melt flow rate of copolymerized polyethylene terephthalate was measured according to ASTM D1238 at a load of 2160 g and a temperature of 190 ° C. The metal atom content of the resin composition was measured by a fluorescent X-ray measurement method. The intrinsic viscosity was measured at 30 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio = 1/1). The crystallization and melting peaks are JIS-K712.
1. In accordance with JIS-K7122, temperature rising rate 20 ° C /
The measurement was performed by raising the temperature to 300 degrees in minutes. The acetaldehyde content was extracted with hot water at 160 ° C. for 2 hours and quantified by gas chromatography.

[Details of test contents] (1) Acetaldehyde odor sensory test A target sheet was cut into a rectangular shape of 20 cm × 40 cm square, folded back at the center of the long side and heat-sealed to obtain 1000 cc of demineralized water. An enclosed pouch was prepared, and the pouch was stored in an environment of 55 ° C. After 4 days, the mixture was cooled to 23 ° C., opened, and a sensory test was conducted for the odor of the contents. In this test, five trained panelists evaluated the results on the basis of a 5-level evaluation, and the average value thereof was used as the test result. The contents of the 5-grade evaluation are 0: no odor is felt, 1: odor is slightly felt, 2: odor is weakly felt, 3: odor is felt, 4: odor is strongly felt.

(2) d-Limonene Adsorption Test The innermost layer of the target multi-layered sheet was cut into a square shape of 4 cm square, the weight of the sheet was measured, and the sheet was dipped in a 100% liquid d-limonene fragrance solution. It was stored under an environment of a temperature of 23 ° C. After 2 weeks, the sheet was quickly taken out and simultaneously wiped with a filter paper to remove d-limonene adhering to the surface of the sheet, and then the weight of the sheet was measured. The amount of adsorbed d-limonene (% by weight) on the sheet was calculated from the change in the weight of the sheet before and after immersion in d-limonene.

(3) Interlayer Adhesion Test A two-layer sheet was prepared by laminating the innermost layer of the target multilayer sheet on the adhesive layer, and the sheet was cut to have a width of 15 mm, and the innermost layer and the adhesive layer were separated. Stripped T-shaped
A sample for measuring the letter-shaped peel strength was prepared. Maleic anhydride graft modified polyolefin (MFR:
6.0, grafted amount of maleic anhydride: 0.01% by weight,
Base polyolefin: 1-butene 20 mol% copolymerized polyethylene) was used. The T-shaped peel strength is 2
The measurement was performed under the conditions of a temperature of 3 ° C. and a relative humidity of 50% using a tensile tester under conditions of a chuck distance of 100 mm and a pulling speed of 300 mm / min. In this measurement, 5 points were measured in each of the longitudinal direction and the lateral direction of the sheet, and the average value was taken as the peel strength.

(4) Heat-sealing test The sheet was left standing at a temperature of 23 ° C. and a relative humidity of 50% for 5 days, then the sheet was folded in two and the thickness was 100 μ from both sides.
The sheet was sandwiched by a Teflon sheet of m and heat-sealed with a bar sealer at a temperature of 140 ° C., a pressure of 5 Kg / cm ² , and a time of 2.5 seconds. Then, after removing the Teflon sheet, a strip-shaped T-shaped peel strength measurement sample was cut out so that the width of the heat-sealed portion was 15 mm. T-shaped peel strength is 23 ℃, relative humidity is 5
Chuck distance 1 using a tensile tester under 0% environment
The measurement was performed under the conditions of 00 mm and a pulling speed of 300 mm / min. In this measurement, 5 points were measured in each of the longitudinal direction and the lateral direction of the sheet, and the average value was taken as the peel strength.

[Raw materials used in the test] (1) Polyester used as a raw material: A-1: The dicarboxylic acid component was entirely terephthalic acid, and the diol component was 95 mol% of ethylene glycol,
Copolymerized polyethylene terephthalate consisting of 1,4-cyclohexanedimethanol 3 mol% and diethylene glycol 2 mol% (intrinsic viscosity 0.72 dl / g) A-2: Dicarboxylic acid component is entirely terephthalic acid, diol component is ethylene glycol 88 Mol%,
Copolymerized polyethylene terephthalate consisting of 1,4-cyclohexanedimethanol 10 mol% and diethylene glycol 2 mol% (intrinsic viscosity 0.71 dl / g)

A-3: The dicarboxylic acid component is entirely terephthalic acid, and the diol component is ethylene glycol 8
Copolymerized polyethylene terephthalate consisting of 8 mol%, 2-butyl-2-ethyl-1,3-propanediol 10 mol%, and diethylene glycol 2 mol% (intrinsic viscosity 0.71 dl / g) A-4: terephthale is a dicarboxylic acid component Acid 97 mol%,
Copolymerized polyethylene terephthalate consisting of 3 mol% of isophthalic acid and 78 mol% of ethylene glycol, 20 mol% of 1,4-cyclohexanedimethanol and 2 mol% of diethylene glycol (intrinsic viscosity 0.67 dl / g)

A-5: The dicarboxylic acid component is entirely terephthalic acid, and the diol component is ethylene glycol 6
Copolymerization polyethylene terephthalate consisting of 7 mol%, cyclohexanedimethanol 30 mol% and diethylene glycol 3 mol% (intrinsic viscosity 0.68 dl / g) A-6: dicarboxylic acid component is entirely terephthalic acid, diol component is ethylene glycol 98 Polyethylene terephthalate consisting of mol% and diethylene glycol 2 mol% (intrinsic viscosity 0.72 dl / g)

A-7: Copolymerized polyethylene terephthalate having a dicarboxylic acid component of 90 mol% terephthalic acid and 10 mol% of isophthalic acid and a diol component of 98 mol% ethylene glycol and 2 mol% of diethylene glycol (intrinsic viscosity 0.70 dl / G) A-8: The dicarboxylic acid component consists entirely of terephthalic acid, the diol component is ethylene glycol 89 mol%,
Copolymerized polyethylene terephthalate consisting of 10 mol% of 1,4-cyclohexanedimethanol and 1 mol% of diethylene glycol (0.3% by weight of potassium carbonate during polymerization)
Copolymerized polyethylene terephthalate with addition of diethylene glycol suppressed, intrinsic viscosity 0.70 dl /
g)

(2) Additives used as raw materials, polyolefin: B-1: titanium dioxide B-2: 20 mol% 1-butene copolymerized polyethylene graft-modified with 0.4 mol% maleic anhydride (melt flow Rate 2.0 g / 10 min) B-3: Zinc ionized product of methacrylic acid copolymerized polyethylene (Himilan R 1650 which is an ionomer resin manufactured by Mitsui DuPont Polychemical Co., melt flow rate 1.5 g / 10 min) B-4: Low density polyethylene (melt flow rate 1.
8g / 10 minutes)

[Example 1] A-2 was used as the copolymerized polyethylene terephthalate in the innermost layer. In addition, the maleic anhydride graft modified polyolefin (MF
R: 6.0, maleic anhydride graft amount: 0.01% by weight, base polyolefin: 1-butene 20 mol% copolymerized polyethylene) were used.

After the copolymerized polyethylene terephthalate for the innermost layer is sufficiently dried, the modified polyolefin for the substrate is still undried and supplied to a 40 mmφ uniaxial extruder, and coextruded by a cast sheet molding machine. A multilayer sheet having an inner layer thickness of 30 μm and a substrate thickness of 20 μm was obtained. This sheet had a supple feel and a high flexibility. The innermost layer has a resin temperature of 265.
C., the substrate was extruded at a resin temperature of 220.degree. C., and the casting roll surface temperature was 40.degree.

Table 1 shows the measurement results of metal atom content, crystallization and melting peak temperatures, heat of cold crystallization, and acetaldehyde content regarding the innermost layer of this multilayer sheet. Table 2 shows the results of acetaldehyde odor sensory test, d-limonene adsorption test, interlayer adhesion test, and heat seal test for this multilayer sheet.

Example 2 The same procedure as in Example 1 was carried out except that the copolymerized polyethylene terephthalate for the innermost layer was supplied to the 40 mmφ twin-screw extruder having a vent connected to the vacuum system while being undried. A multilayer sheet having an inner layer thickness of 30 μm and a substrate thickness of 20 μm was obtained. This sheet had a supple feel and a high flexibility. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet, and Table 2 shows the same test results as in Example 1 regarding this multilayer sheet.

Example 3 The innermost layer had a thickness of 30 μm and the substrate had a thickness of 2 in the same manner as in Example 2 except that A-3 was used as the copolymerized polyethylene terephthalate in the innermost layer.
A multilayer sheet having a thickness of 0 μm was obtained. This sheet had a supple feel and a high flexibility. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet.
Table 2 shows the same test results as in Example 1 for this multilayer sheet.

Example 4 The innermost layer had a thickness of 30 μm and the substrate had a thickness of 2 in the same manner as in Example 2 except that A-4 was used as the copolymerized polyethylene terephthalate in the innermost layer.
A multilayer sheet having a thickness of 0 μm was obtained. This sheet had a supple feel and a high flexibility. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet.
Table 2 shows the same test results as in Example 1 for this multilayer sheet.

Example 5 93 parts of A-1 as copolymerized polyethylene terephthalate and 7 parts of B-2 as an additive.
A multilayer sheet having an innermost layer having a thickness of 30 μm and a substrate having a thickness of 20 μm was obtained in the same manner as in Example 2 except that the components were mixed and used as the innermost layer. This sheet had a supple feel and a high flexibility. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet, and Table 2 shows the same test results as in Example 1 regarding this multilayer sheet.
Shown in

Comparative Example 1 The innermost layer had a thickness of 30 μm and the substrate had a thickness of 2 in the same manner as in Example 2 except that A-5 was used as the copolymerized polyethylene terephthalate in the innermost layer.
A multilayer sheet having a thickness of 0 μm was obtained. Since this sheet was amorphous, no crystallization or melting peak was observed. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet. D for this multilayer sheet
-The results of the limonene adsorption test are shown in Table-2.

[Comparative Example 2] A-6 was used as the polyethylene terephthalate as the innermost layer, and the innermost layer had a resin temperature of 285.
A multilayer sheet having an innermost layer having a thickness of 30 μm and a substrate having a thickness of 20 μm was obtained in the same manner as in Example 2 except that the sheet was extruded at a temperature of ° C. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet. Table 2 shows the results of acetaldehyde odor sensory test, interlayer adhesion test, and heat seal test for this multilayer sheet.

Comparative Example 3 The innermost layer had a thickness of 30 μm and the substrate had a thickness of 2 in the same manner as in Example 2 except that A-7 was used as the copolymerized polyethylene terephthalate in the innermost layer.
A multilayer sheet having a thickness of 0 μm was obtained. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet.
Table 2 shows the results of the interlayer adhesion test and the heat seal test for this multilayer sheet.

Comparative Example 4 The thickness of the innermost layer was the same as that of Comparative Example 2 except that 93 parts of A-6 as polyethylene terephthalate and 7 parts of B-2 as an additive were blended and used as the innermost layer. Was obtained and the thickness of the base material was 20 μm. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet. Table 2 shows the results of acetaldehyde odor sensory test, interlayer adhesion test, and heat seal test for this multilayer sheet.

[Comparative Example 5] 93 parts of A-2 as copolymerized polyethylene terephthalate and 7 parts of B-3 as an additive.
A multilayer sheet having an innermost layer having a thickness of 30 μm and a substrate having a thickness of 20 μm was obtained in the same manner as in Example 2 except that the components were mixed and used as the innermost layer. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet. The results of the acetaldehyde odor sensory test for this multilayer sheet are shown in Table-2.

Comparative Example 6 The innermost layer had a thickness of 30 μm and the substrate had a thickness of 2 in the same manner as in Example 2 except that A-8 was used as the copolymerized polyethylene terephthalate in the innermost layer.
A multilayer sheet having a thickness of 0 μm was obtained. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet.
Table 2 shows the results of acetaldehyde odor sensory test, interlayer adhesion test, and heat seal test for this multilayer sheet.
Shown in

Comparative Example 7 99.8 parts of A-2 as copolymerized polyethylene terephthalate and B-1 as an additive
Was used in the innermost layer in the same manner as in Example 2 except that 0.2 part was mixed with 0.2 part of
A multilayer sheet having a thickness of μm was obtained. Table 1 shows the same measurement results as in Example 1 regarding the innermost layer of this multilayer sheet. Table 2 shows the results of the interlayer adhesion test and the heat seal test for this multilayer sheet.

[Comparative Example 8] A single layer sheet having a thickness of 30 µm formed only from B-4 was subjected to a d-limonene adsorption test. Table 2 shows the results.

[0060]

[Table 1] In the table, Tc indicates a crystallization peak temperature and Tm indicates a melting peak temperature.

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

EFFECT OF THE INVENTION The multilayer packaging material of the present invention is excellent in aroma retention, adhesiveness, impact resistance, flexibility, pinhole resistance, spreadability, and the like. Excellent adhesion. Therefore, the multilayer packaging material of the present invention can be preferably used as a packaging material for contents such as beverages, foods, cosmetics, etc., in which the change of aroma components is not desired. For example, when the multilayer packaging material of the present invention is used as an interior material for a paper pack, it is possible to provide a suitable large-sized beverage container because it is excellent in aroma retaining property and heat sealing property. Further, when used for a standing pouch, it is possible to provide a retort packaging container having high resistance to load and drop impact due to its excellent heat-sealing property and interlayer adhesiveness, and thus the multilayer packaging material of the present invention and the same. The container has high industrial value.

Front page continuation (72) Inventor Masahiro Narui 1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Institute

Claims (6)

[Claims] 1. A copolymerization component having an intrinsic viscosity of 0.5 to 1.5 dl / g and having an alicyclic ring and / or a linear or branched aliphatic chain having 3 or more carbon atoms has a copolymerization ratio of 2
A multi-layer packaging material comprising an innermost layer of a resin composition containing, as a main component, copolymerized polyethylene terephthalate in an amount of ˜25 mol%, wherein the resin composition has a metal atom content of 0. A multi-layer packaging material, which is 1% by weight or less, has a crystallization peak temperature at a temperature rise of 130 to 200 ° C., and has a cold crystallization heat amount of 15 to 40 J / g. 2. The melting peak temperature of the resin composition used as the innermost layer is higher than the crystallization peak temperature at the time of heating,
And the difference is 95 degreeC or less, The multilayer packaging material of Claim 1 characterized by the above-mentioned. 3. The multilayer packaging material according to claim 1 or 2, wherein the resin composition used as the innermost layer has an acetaldehyde content of 0.01% by weight or less. 4. A copolymerization component having an alicyclic ring and / or a linear or branched aliphatic chain having 3 or more carbon atoms is cyclohexanedimethanol and / or 2-butyl-
The multi-layer packaging material according to any one of claims 1 to 3, which is 2-ethyl-1,3-propanediol. 5. The multilayer packaging material according to claim 1, wherein the base material includes one or more layers selected from a polyethylene layer, a paper layer and an aluminum layer. 6. A multilayer packaging container formed by heat-sealing innermost layers of the multilayer packaging material according to any one of claims 1 to 5.