JP3193565B2 - Polyester multilayer sheet and container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester-based multilayer sheet having excellent gas barrier properties, strength, and secondary processability (container moldability), high transparency, and a container obtained by thermoforming the sheet. In particular, the present invention relates to a sheet suitable as a food packaging material and a container using the sheet.

[0002]

2. Description of the Related Art Conventionally, thermoplastic polyester resins mainly composed of polyethylene terephthalate have been focused on excellent mechanical properties, transparency, secondary workability, chemical resistance, fragrance retention, hygiene, etc. of the material. It is formed into various films, sheets, containers and the like, and is widely used as a packaging material. In particular, in recent years, due to the problem of environmental pollution caused by incineration of waste, attention has been paid to it as a substitute for vinyl chloride resin, and production has been rapidly increasing.

On the other hand, containers such as cups and trays formed by heating and softening a plastic sheet are used for foods, beverages,
Widely used in the field of pharmaceuticals. Some applications of these thermoformed containers require a gas barrier property against oxygen in order to prevent oxidative deterioration of the package contents.

Hitherto, multilayer sheets having a laminated structure have been used to manufacture these containers having gas barrier properties. Most of them use a multilayer sheet in which an ethylene-vinyl alcohol copolymer is used as an intermediate layer for providing gas barrier properties, and a polypropylene layer is formed on both sides of the intermediate layer via an adhesive layer.

[0005] A container molded from this sheet is excellent in gas barrier properties as compared with a transparent container molded from a thermoplastic polyester sheet, but has insufficient transparency and is not suitable for applications that emphasize contents transparency. . Further, the energy generated during incineration is about twice that of polyester, which is not preferable from the viewpoint of environmental suitability. As described above, there has been a demand for a material that can be used for a container that uses a thermoplastic polyester resin having good transparency and has excellent gas barrier properties.

Hitherto, as a method for improving the gas barrier properties of thermoplastic polyester, use of a polyester resin comprising isophthalic acid and ethylene glycol has been proposed. However, although a sheet made of this resin has improved gas barrier properties, it cannot be used alone because mechanical properties such as impact resistance are significantly reduced. Attempts have also been made to co-extrude a thermoplastic polyester and an ethylene-vinyl alcohol copolymer to form a multilayer sheet, but this is difficult because the two types of resin processing temperatures are significantly different.

For this reason, at present, a sheet in which a transparent thermoplastic polyester sheet and a multilayer gas barrier film are bonded by a method such as dry lamination is used.
However, the additional laminating step not only lowers the productivity but also increases the cost. In addition, there are problems that the transparency after the secondary molding is inferior to that of the single-layer thermoplastic polyester sheet, and the gas barrier property is not stable.

Japanese Patent Application Laid-Open No. 62-62749 discloses a three-layer heat-resistant container in which a polyamide formed from meta-xylene diamine and adipic acid is used as an intermediate layer and polyethylene terephthalate is formed on both surfaces thereof. The present invention focuses on the crystallization resistance of polyethylene terephthalate, and the container becomes opaque and is based on a concept different from that of the present invention.

Furthermore, Japanese Patent Publication No. 63-59873 discloses a metaxylylene group-containing polyamide resin formed from metaxylylenediamine and adipic acid as an intermediate layer.
A composite film in which polyethylene terephthalate is formed on both surfaces thereof and stretched is described. However, when a metaxylylene group-containing polyamide resin is used alone in the intermediate layer, the unstretched film has low strength and cannot be put to practical use.
Further, the stretched film has a disadvantage that the secondary workability, particularly the deep drawability, is reduced. Further, there is a disadvantage that a stretching step is required in the manufacturing process, and a manufacturing trouble is likely to occur. Thus, conventionally, with polyester resin,
Although it is desired to produce sheets and containers by an economical production method with excellent transparency, excellent gas barrier properties and strength, practical sheets and containers have not been found.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyester-based multilayer sheet which is excellent in gas barrier properties, strength and secondary workability and has high transparency, and a container using the same. The present inventors have excellent mechanical properties, transparency, and secondary processing properties of a thermoplastic polyester resin,
As a result of intensive studies to improve the barrier property against oxygen without impairing chemical resistance, fragrance retention, hygiene, etc., as the intermediate layer of the multilayer sheet, a metaxylylene group-containing polyamide resin and nylon etc. were specified. The problem is solved by using a resin composition obtained by giving a history of heating the resin composition containing the resin composition to a temperature of 280 ° C. or more and less than 320 ° C. The multilayer sheet and the container of the present invention I came to find it.

[0011]

Means for Solving the Problems A first invention of the present invention is:
120 μm thick consisting of at least three thermoplastic resin layers
A multilayer sheet of 2.5 mm, consisting of (A) the surface layer contains a thermoplastic polyester resin containing ethylene terephthalate as the main repeating unit, (B) an intermediate layer is below the component (a) and component (b) 280 to the resin composition
(A) component and (b) at a temperature of not less than 320 ° C.
A transamidation reaction occurs between the two polyamides
NetsuNaru characterized by containing a resin composition obtained by applying heat history block copolymer is produced
Polyester multilayer sheet for shape . Component (a): metaxylylene group-containing polyamide resin 90
Component (b): 10 to 50% by weight of thermoplastic polyamide resin other than component (a)

The second invention is a multilayer sheet having a thickness of 120 μm to 2.5 mm comprising at least three thermoplastic resin layers, wherein (A) a thermoplastic polyester resin having a surface layer mainly composed of ethylene terephthalate as a repeating unit. Containing (B) the intermediate layer to a resin composition comprising the following components (a) and (b) at a temperature of 280 ° C. or more and less than 320 ° C.
Between the two types of polyamides (a) and (b)
The transamidation reaction takes place in the
The intermediate layer at a temperature of 160 ° C.
/ 2 The heat characterized by a crystallization time of 10 seconds or more
Polyester multilayer sheet for molding . Component (a): metaxylylene group-containing polyamide resin 90
Component (b): 10 to 50% by weight of a thermoplastic polyamide resin other than the component (a). In a third aspect, the polyester multilayer sheet of the first or second aspect is thermoformed. A container comprising:

Hereinafter, the present invention will be described in detail. The thermoplastic polyester resin having ethylene terephthalate as a main repeating unit as referred to in the present invention generally means terephthalic acid in which 80% by mole or more, preferably 90% by mole or more of the acid component, and 80% by mole or preferably 80% by mole of the glycol component. 90
It means a polyester in which at least mol% is ethylene glycol, and the remaining other acid components are isophthalic acid, orthophthalic acid, diphenyl ether 4,4′-dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid , Succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecandioic acid, sulfoisophthalic acid, hexahydroxyterephthalic acid, and the like.

Other glycol components include 1,2-propylene glycol, 1,4-butanediol, 1,5
-Pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, 1,4-dicyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane , 2,2-bis (4-hydroxyethoxyphenyl) propane, or a polyester resin containing p-oxybenzoic acid, p-hydroxyethoxybenzoic acid, or the like as an oxyacid. Further, a blend in which ethylene terephthalate is in the above range by blending two or more polyesters may be used.

The thermoplastic polyester resin of the present invention has an intrinsic viscosity of 0.55 or more, preferably 0.65 to 1.3. Intrinsic viscosity is 0.
If it is less than 55, whitening due to crystallization tends to occur during sheet molding, it is difficult to obtain a transparent sheet, and the mechanical strength of the obtained container is also insufficient.

Further, the metaxylylene group-containing polyamide resin used in the present invention comprises metaxylylenediamine or a mixed xylylenediamine containing metaxylylenediamine and 30 mol% or less of the total amount of paraxylylenediamine;
Α, ω-aliphatic dicarboxylic acid having 6 to 10 carbon atoms in the molecule at least 70 mol% in the molecule
It is a contained polymer.

Examples of these polymers include homopolymers such as polymetaxylylene adipamide, polymetaxylylene secapamide, polymetaxylylene speramide, and the like, and metaxylylene / paraxylylene adipamide copolymer. And copolymers such as meta-xylylene / para-xylylene pimeramide copolymer, meta-xylylene / para-xylylene azeramide copolymer, and components of these homopolymers or copolymers and hexamethylene diamine. Aliphatic diamines, alicyclic diamines such as piperazine, aromatic dicarboxylic acids such as para-bis- (2-aminoethyl) benzene, lactams such as ε-caprolactam, ω- such as γ-aminoheptanoic acid Copolymerization with aminocarboxylic acids, aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid, etc. Copolymer, and the like.
In the above copolymer, paraxylylenediamine accounts for 30 mol% or less based on the total xylylenediamine, and the constitutional unit formed from xylylenediamine and aliphatic dicarboxylic acid accounts for at least 70 mol% in the molecular chain. It is.

The metaxylylene group-containing polyamide resin is
It is necessary that the relative viscosity is 1.5 or more, preferably 2.0 to 4.0. If the relative viscosity is less than 1.5, it is difficult to use because it is brittle in an amorphous state.

The above polyamide resin has high gas barrier properties. That is, the meta-xylylene group-containing polyamide resin has a gas barrier property close to that of the conventionally widely used ethylene-vinyl alcohol copolymer, and more notably, in a high humidity environment, ethylene-vinyl alcohol copolymer It has even higher gas barrier properties than vinyl alcohol copolymers. General nylon 6
Do not have such high gas barrier properties.

Further, (A) used for the intermediate layer (B)
As the thermoplastic polyamide resin other than the components, nylon 6, nylon 6,6, nylon 6,10, nylon 1
1, nylon 12, nylon 4,6, nylon 6-6
Polymers such as 6 can be used.

For the intermediate layer, it is essential to use a resin composition comprising the components (a) and (b).
When the intermediate layer is formed by using only the component alone, the strength is remarkably low and is not suitable for practical use. When the intermediate layer is formed by using only the component (b) alone, the strength is improved, but the gas barrier property is reduced. From the viewpoint of strength, it is preferable that the amount of the component (b) is large, but considering the gas barrier properties, the amount of the component (b) used is preferably 10 to 50% by weight. Particularly preferably, 15
４０40% by weight. In addition, when the component (a) alone absorbs moisture, spherulites grow by heating and diffusely reflect light, thereby lowering the transparency of the molded product. However, the combined use of the component (b) can prevent the reduction in transparency. It becomes possible.

It is necessary that the resin composition of the intermediate layer undergoes at least one heat history at a resin temperature of 280 ° C. or more and less than 320 ° C. until a multilayer sheet is obtained. This is presumed to cause a transamidation reaction. With this resin composition, a sheet having a half crystallization time of 10 seconds or more can be obtained at a constant temperature crystallization at 160 ° C. by a measurement method using a depolarization photometric method, whereby gas barrier properties, strength and secondary A transparent multilayer sheet excellent in processability can be obtained. 1/2 of sheet
By setting the crystallization time to 10 seconds or more, the container molding time can be appropriately selected, and a high quality product can be manufactured.

The step of heating the resin composition of the intermediate layer to a resin temperature of 280 ° C. or more and less than 320 ° C. to give at least one heat history may be performed at the time of sheet molding, or may be performed before sheet molding. It is also possible to give at the time of kneading. When a resin composition that has undergone thermal history before sheet molding is used, a transparent sheet can be obtained even when the temperature during sheet molding is lower than 280 ° C.

When the heat history temperature of the resin composition is lower than 280 ° C., the barrier properties, strength and secondary workability are not good, and only a sheet having poor transparency can be obtained. Further, there is a disadvantage that the temperature range in which the sheet can be formed by thermoforming such as vacuum forming becomes extremely narrow, and it is impossible to stably form a container or the like. On the other hand, when the heat history temperature is 320 ° C. or higher, there is a disadvantage that the resin is deteriorated, the mechanical properties are reduced, and the discoloration proceeds by heating. The time of the thermal history of the resin composition of the intermediate layer is not particularly limited, and may be 1 hour at the constant temperature crystallization at 160 ° C.
It is necessary to provide a heat history at a temperature of 280 ° C. or more and less than 320 ° C. so that a crystallization time of which is more than 10 seconds can be obtained. The time of the heat history varies depending on the shape of the device used, such as a kneader, a single-screw extruder, and a twin-screw extruder in the same direction / different direction, the size of the scale of the device, and the operating conditions (the number of revolutions, the charged amount, etc.) For example, it is generally 1 to 15 minutes, preferably 5 to 10 minutes at 290 ° C., and 30 seconds to 5 minutes, preferably about 1 to 3 minutes at 310 ° C.

POLYMER, 1991, Volume
No. 32, Number 15 2771, when a blend of polymethaxylylenediamine adipamide and nylon 6 was melt-extruded at 290 ° C., the transamidation reaction (interchange reaction) between the two polyamides was carried out.
ion) occurs, resulting in the formation of a block polymer, which results in a clear homogeneous product. According to this report, it is presumed that the resin composition of the intermediate layer of the present invention undergoes an amide exchange reaction to form a block copolymer.

In the resin or resin composition of (A) the surface layer and (B) the intermediate layer, if necessary, a coloring agent, an ultraviolet absorber, an antistatic agent, a thermal antioxidant, an antibacterial agent, a lubricant, a blocking resistance agent And additives such as stabilizers can be contained in an appropriate ratio.

The method for imparting heat history to the resin composition of the intermediate layer is not particularly limited, and may be carried out by any method. For example, there is a method of preliminarily mixing with a Henschel mixer and then mechanically kneading with a Banbury mixer, a twin screw extruder or the like.

The multilayer sheet and the container of the present invention use a thermoplastic polyester resin as the inner and outer (A) surface layers, and (B) 90 to 50% by weight of a metaxylylene group-containing polyamide resin (a) as an intermediate layer. (B) A resin composition containing 10 to 50% by weight of a thermoplastic polyamide resin other than the component (a) and having a half crystallization time of 10 seconds or more at a constant temperature crystallization at 160 ° C. is used. In some cases, it is also possible to form an adhesive layer between the intermediate layer and the surface layer.

The multilayer sheet of the present invention can be manufactured and used as a non-stretched sheet and a stretched sheet, but has an advantage that it can be used particularly as a non-stretched sheet. In the multilayer sheet of the present invention, the thickness of the intermediate layer is preferably from 20 μ to 500 μ from the viewpoint of gas barrier properties, and particularly preferably from 40 μ to 300 μ. The thickness of the polyester resin layer forming the surface layer is preferably 50 μm to 1 mm, and particularly preferably 100 μm to 700 μm.
It is. Further, the thickness of the entire sheet is 120 μ to 2.5 mm
And particularly preferably from 240 μm to 1.
7 mm. In addition, it is preferable that the composition ratio of the sheet is set to be equal to or less than 1/2 that of the polyester resin in terms of oxygen permeability from the viewpoint of protecting the contents.

In order to produce the multilayer sheet of the present invention, ordinary lamination methods such as coextrusion, dry lamination, and extrusion lamination can be employed. As the co-extrusion method, an apparatus provided with a plurality of extruders and dies is usually used, but a multi-manifold method, a feed block method and the like are generally adopted.

The container of the present invention is formed by ordinary thermoforming using the multilayer sheet obtained by the present invention, for example, vacuum forming, pressure forming, vacuum pressure forming, plug assist forming, press forming and the like.

[0032]

The present invention will be described in detail with reference to the following examples. First, methods for measuring the crystallization time, the physical properties of the sheet and the physical properties of the container will be described. (1) 1/2 crystallization time: The resin composition of the intermediate layer was separated from the multilayer sheet, and using this test piece, a depolarization photometric method was performed using a polymer crystallization rate measuring device (model: MK701) manufactured by Kokita Seisakusho. (Polymer Chemistry, (1972), vol. 2)
9, No. 325, 336). The test piece at room temperature was placed in a crystallization bath at 160 ° C., heated, crystallized at 160 ° C., and the half crystallization time immediately after immersion in the crystallization bath was determined.

(2) Total light transmittance and haze: using a haze meter MODEL NDH-2D manufactured by Tokyo Denshoku Co., Ltd.
It was calculated from the following equation based on JIS-K7105. In addition,
The container was measured by cutting out the bottom. Total light transmittance = T2 / T1 × 100 (%) T1: incident light amount T2: total light transmission amount T3: scattered light amount by device T4: scattered light amount by device and sample

(3) Oxygen permeability: US MODERN
OX-TRA Oxygen Permeability Measuring Machine manufactured by CONTOROLS
It was measured under the following conditions by N10 / 50A. Sheet: 23 ° C, 70% relative humidity Container: 23 ° C, 70% internal relative humidity, 50% external relative humidity
%

(4) Vacuum formability: PLA manufactured by Sanwa Kogyo Co., Ltd.
A VAC FE-36PH vacuum forming machine was equipped with a round cup-shaped mold (container dimensions; 90 mmφ × 70 mm height),
23 ° C x 50
When vacuum forming was performed using a sheet stored for one week in a% RH environment, a sheet having an appropriate heating temperature condition range of 30 ° C. or more was evaluated as good (〇), and a sheet having a temperature lower than 30 ° C. was evaluated as poor (×).

(5) Sheet impact strength: manufactured by Toyo Seiki Co., Ltd.
Using a DuPont impact tester, measure with a punch tip radius of 6.3 mm in accordance with JIS-K7211, and measure 50%
The breaking energy (J) was determined.

(6) Container Impact Strength: A container molded by the method of (3) is filled with 350 ml of pure water, the upper surface of the container is heat-sealed, then dropped on a vinyl chloride floor, and subjected to JIS.
The 50% breaking height (cm) was determined based on -K7211.

(7) Intrinsic viscosity of polyester resin (I
V): The measurement resin was mixed with a phenol / tetrachloroethane (weight ratio; 50/50) mixed solvent having a solution viscosity of 0.5.
g / 10 ml, and shows the viscosity measured using a Ubbelohde viscometer in a thermostat at 30 ° C.

(8) Relative viscosity of polyamide resin (ηrel
): Relative viscosity measured at 25 ° C. by dissolving 1 g of the measurement resin in 100 ml of 96% by weight sulfuric acid.

Example 1 As the thermoplastic polyester constituting the surface layer (outer layer and inner layer), 50 mol% of terephthalic acid, ethylene glycol 4
Polyethylene terephthalate (hereinafter abbreviated as PET) having an IV of 0.80 and comprising 7.5 mol% and 1.5 mol% of 1,4-cyclohexanedimethanol was used. As the metaxylylene group-containing polyamide resin constituting the intermediate layer, polymetaxylylene adipamide (hereinafter abbreviated as MXD6) with ηrel = 2.7 and nylon 6 (hereinafter abbreviated as Ny6) with ηrel = 3.8 are used. did. Using these resins, using a multilayer sheet molding equipment, the thickness composition ratio of two types and three layers by the coextrusion method is as follows: surface layer (outer): intermediate layer:
A multilayer sheet having a thickness of 0.8 mm and a surface layer (inner) = 2: 1: 2 was formed. The processing temperature (molten resin temperature) of this sheet was 290 ° C. for the intermediate layer and 280 ° C. for the surface layer. Table 1 shows the resin composition constituting the sheet, and Table 3 shows the half-crystallization time of the intermediate layer and the physical properties of the sheet / container.

Example 2 The same procedure as in Example 1 was carried out except that a blend of 70% by weight of MXD6 and 30% by weight of Ny6 was used as the intermediate layer. Table 1 shows the resin composition of the sheet, and Table 3 shows the half-crystallization time of the intermediate layer, and the physical properties of the sheet and the container. Example 3 The same method as in Example 1 was used except that a blend of 60% by weight of MXD6 and 40% by weight of Ny6 was used as the intermediate layer. Table 1 shows the resin composition of the sheet, and Table 3 shows the half-crystallization time of the intermediate layer, and the physical properties of the sheet and the container.

Example 4 In Example 1, the processing temperature (molten resin temperature) during sheet processing was 280 ° C. for the intermediate layer and 280 ° C. for the surface layer. Table 1 shows the resin composition of the sheet, and Table 3 shows the half-crystallization time of the intermediate layer, and the physical properties of the sheet and the container. Example 5 In Example 1, the processing temperature (molten resin temperature) during sheet processing was 285 ° C. for the intermediate layer and 280 ° C. for the surface layer. Table 1 shows the resin composition of the sheet, and Table 3 shows the half-crystallization time of the intermediate layer, and the physical properties of the sheet and the container.

Example 6 In Example 1, the processing temperature (molten resin temperature) during sheet processing was 300 ° C. for the intermediate layer and 280 ° C. for the surface layer. Table 1 shows the resin composition of the sheet, and Table 3 shows the half-crystallization time of the intermediate layer, and the physical properties of the sheet and the container. Example 7 In Example 1, MXD was used as the resin composition for the intermediate layer.
6 and Ny6 were kneaded in advance using a twin screw extruder at a processing temperature of 290 ° C., and the same procedure was performed except that the processing temperature of the resin composition of the intermediate layer was 270 ° C. Was. Table 1 shows the resin composition of the sheet and the thermal history of the intermediate layer. Table 3 shows the half crystallization time of the intermediate layer.
This shows the physical properties of the sheet and container.

Comparative Example 1 The procedure of Example 1 was repeated, except that MXD6 was used alone as the intermediate layer. Table 2 shows the resin constituting the sheet, and Table 3 shows the half-crystallization time of the intermediate layer and the physical properties of the sheet and the container. The strength of the sheets and containers is low and not practical. Comparative Example 2 A sheet was formed in the same manner as in Comparative Example 1, except that the thickness ratio of PET to MXD6 was 4: 1.
Table 2 shows the resin constituting the sheet, and Table 3 shows the half-crystallization time of the intermediate layer and the physical properties of the sheet and the container. The strength of the sheet and the container is low, and the container moldability is poor, which is not practical.

Comparative Example 3 The same procedure as in Example 1 was performed except that a blend of 40% by weight of MXD6 and 60% by weight of Ny6 was used as the intermediate layer. Table 2 shows the resin composition of the sheet, and Table 3 shows the half-crystallization time of the intermediate layer, and the physical properties of the sheet and the container. The haze and oxygen permeability of the sheet and container are poor and not practical. Comparative Example 4 The same procedure as in Example 1 was carried out except that a blend of MXD6 of 20% by weight and Ny6 of 80% by weight was used as the intermediate layer. Table 2 shows the resin composition of the sheet, and Table 3 shows the half-crystallization time of the intermediate layer, and the physical properties of the sheet and the container. The haze and oxygen permeability of the sheet and container are poor and not practical.

Comparative Example 5 The procedure was the same as in Example 1, except that polymetaxylylene adipamide and nylon 6 were used, and the processing temperature during sheet molding was 270 ° C. for the intermediate layer only. Table 2 shows the resin composition constituting the sheet, and Table 3 shows the half crystallization time and sheet properties of the intermediate layer. In addition, the container had a high crystallization rate and could not be molded.

Comparative Example 6 In Example 1, the processing temperature (molten resin temperature) during sheeting was 320 ° C. for the intermediate layer and 280 ° C. for the surface layer.
The intermediate layer resin was severely deteriorated, and a good multilayer sheet could not be obtained. Comparative Example 7 A 0.8 mm sheet of a PET single layer was formed. Table 2 shows the resin composition of the sheet, and Table 3 shows the physical properties of the sheet and the container. Poor oxygen permeability is not practical.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

According to the present invention, the surface layer is made of a thermoplastic polyester resin, the intermediate layer is made of a mixed composition of a specific ratio of a methacrylylene group-containing polyamide resin and nylon, etc. By the multilayer sheet containing the resin composition obtained by giving the heat history, a sheet and a container having improved gas barrier properties over polyester can be obtained.

Continuation of the front page (56) References JP-A-4-198329 (JP, A) JP-A-2-248249 (JP, A) JP-A-4-103348 (JP, A) JP-B-63-59873 (JP) , B2) (58) Fields studied (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B29C 51/00-51/46

Claims (3)

(57) [Claims] 1. A multilayer sheet having a thickness of 120 μm to 2.5 mm, comprising at least three thermoplastic resin layers,
(A) a surface layer containing a thermoplastic polyester resin having ethylene terephthalate as a main repeating unit;
The intermediate layer is below the component (a) and (b) Oite to consist component resin composition to a temperature below 2 80 ° C. or higher 320 ° C.
Amide between the two polyamides (a) and (b)
A polyester multilayer sheet for thermoforming , characterized by containing a resin composition obtained by giving a heat history of generating a block polymer by an exchange reaction . Component (a): metaxylylene group-containing polyamide resin 90
Component (b): 10 to 50% by weight of thermoplastic polyamide resin other than component (a) 2. A multilayer sheet having a thickness of 120 μm to 2.5 mm, comprising at least three thermoplastic resin layers,
(A) a surface layer containing a thermoplastic polyester resin having ethylene terephthalate as a main repeating unit;
Resin whose intermediate layer comprises the following components (a) and (b)
At a temperature of at least 280 ° C and less than 320 ° C, the composition
Amide between the two polyamides (a) and (b)
Thermal history of block polymer generated by exchange reaction
A resin composition obtained by providing, thermoforming port <br/> Riesuteru, wherein the 1/2 crystallization time at temperature 160 ° C. of the resin composition of the intermediate layer is more than 10 seconds Series multilayer sheet. Component (a): metaxylylene group-containing polyamide resin 90
Component (b): 10 to 50% by weight of thermoplastic polyamide resin other than component (a) 3. A container obtained by thermoforming the polyester-based multilayer sheet according to claim 1.