Thermoplastic resin foam sheet, thermoplastic resin foam sheet molded product, and method for manufacturing thermoplastic resin foam sheet molded product

Abstract

To provide a thermoplastic resin foam sheet which is excellent in moldability, in consideration of in a prior art, in a container having a large drawing ratio and a container having a complicated uneven shape, molding is difficult.SOLUTION: A thermoplastic resin foam sheet has a sheet-like foam layer containing a thermoplastic resin, wherein the thermoplastic resin contains a polyester-based resin and a polyetherimide-based resin, and a storage elastic modulus determined by solid viscoelasticity measurement at heating speed of 5°C / min and a frequency of 1 Hz has a minimum value (E'A) at a measurement temperature of 30-200°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic resin foam sheet, a molded thermoplastic resin foam sheet, and a method for producing a molded thermoplastic resin foam sheet. [Background technology]

[0002] BACKGROUND ART Resin foam sheets obtained by foaming thermoplastic resins such as polystyrene-based resins and molded articles thereof have been used for food containers and the like because of their light weight and high heat insulating properties. The market for ready-to-eat meals, where people purchase pre-cooked foods from convenience stores, supermarkets, and other retailers and eat them at home, is expanding. This market demands food containers that can be used for cooking in a microwave oven. These containers must be resistant to deformation when heated in a microwave oven (excellent dimensional stability), and must be easy to handle after heating without becoming soft (excellent heat resistance).

[0003] For example, Patent Document 1 proposes a thermoplastic resin foam sheet containing a polyester resin and a polyetherimide resin as thermoplastic resins and having a single glass transition temperature (Tg). The invention of Patent Document 1 aims to improve heat resistance strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6864775 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, a thermoplastic resin foam sheet for food containers is required to be able to be molded into a container of a desired shape by thermoforming, etc. (excellent moldability) In particular, excellent moldability is required for containers with a large drawing ratio, which is expressed as (internal dimension of container depth) / (opening diameter of container opening), or containers with complex uneven shapes. Furthermore, when a thermoplastic resin foam sheet molded body is molded from a thermoplastic resin foam sheet, it is required that the container will not break even if it is subjected to physical impact such as being dropped during transportation when cooked food is placed in the container and transported (it must have excellent impact resistance).

[0006] Therefore, an object of the present invention is to provide a thermoplastic resin foam sheet having excellent moldability and a thermoplastic resin foam sheet molded article having excellent impact resistance. [Means for solving the problem]

[0007] As a result of extensive investigations by the present inventors, it has been found that in a thermoplastic resin foam sheet containing a polyester resin and a polyetherimide resin, the storage modulus determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz is a minimum value (E' A ) can improve moldability, and thus the present invention has been completed.

[0008] That is, the present invention has the following aspects. <1> a sheet-like foam layer containing a thermoplastic resin; the thermoplastic resin includes a polyester-based resin and a polyetherimide-based resin, The storage modulus determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1Hz is a minimum value (E' A ) A thermoplastic resin foam sheet. <2> The minimum value (E' A ) is 1.0 to 10.0 MPa, <1> The thermoplastic resin foam sheet according to claim 1. <3> The storage modulus (E') at 30°C was determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1Hz. 30 ) and the minimum value (E' A ) and the ratio (E' 30 / E' A ) is between 40 and 400, <1> or <2> The thermoplastic resin foam sheet according to claim 1. <4> The Z-average molecular weight (M Z ) is 300,000 to 700,000, <1> ~ <3> 10. The thermoplastic resin foam sheet according to any one of claims 1 to 9. <5> The temperature (t') at which the loss tangent (tanδ) is maximized by measuring the solid viscoelasticity at a heating rate of 5°C / min and a frequency of 1Hz. MAX ) is 80 to 130°C in the measurement temperature range of 30 to 200°C, <1> ~ <4> 10. The thermoplastic resin foam sheet according to any one of claims 1 to 9. <6> the content of the polyester resin relative to the total mass of the thermoplastic resin is 60 to 95 mass %, The content of the polyetherimide resin relative to the total mass of the thermoplastic resin is 5 to 40 mass %. <1> ~ <5> 10. The thermoplastic resin foam sheet according to any one of claims 1 to 9. <7> The absolute value of the difference between the endothermic amount and the exothermic amount determined by heat flux differential scanning calorimetry at a heating rate of 10°C / min is 3 to 21 J / g. <1> ~ <6> 10. The thermoplastic resin foam sheet according to any one of claims 1 to 9.

[0009] <8> a sheet-like foam layer containing a thermoplastic resin; the thermoplastic resin includes a polyester-based resin and a polyetherimide-based resin, The minimum storage modulus (E') determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz B ) is 1.0 to 10.0 MPa at a measurement temperature range of 30 to 200°C. <9> The storage modulus (E') at 30°C was determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1Hz. 30 ) and the minimum value (E' B ) and the ratio (E' 30 / E' B ) is between 40 and 200, <8> The thermoplastic resin foam sheet molded article according to claim 1. <10> The Z-average molecular weight (M Z ) is 300,000 to 700,000, <8> or <9> The thermoplastic resin foam sheet molded article according to claim 1. <11> The temperature (t') at which the loss tangent (tanδ) is maximized by measuring the solid viscoelasticity at a heating rate of 5°C / min and a frequency of 1Hz. MAX ) is 80 to 130°C in the measurement temperature range of 30 to 200°C, <8> ~ <10> 2. The thermoplastic resin foam sheet molded article according to claim 1 . <12> the content of the polyester resin relative to the total mass of the thermoplastic resin is 60 to 95 mass %, The content of the polyetherimide resin relative to the total mass of the thermoplastic resin is 5 to 40 mass %. <8> ~ <11> 2. The thermoplastic resin foam sheet molded article according to claim 1 . <13> The absolute value of the difference between the endothermic amount and the exothermic amount determined by heat flux differential scanning calorimetry at a heating rate of 10°C / min is 7 to 28 J / g. <8> ~ <12> 2. The thermoplastic resin foam sheet molded article according to claim 1 . <14> The container body is a cylindrical container body with a bottom, which has a bottom wall portion that is a perfect circle in a plan view and a side wall portion that stands upright from the periphery of the bottom wall portion, and the container body narrows from an opening toward the bottom wall portion, and a drawing ratio expressed as (height of the side wall portion) / (opening diameter of the opening portion) is 0.5 to 2.0. <8> ~ <13> 2. The thermoplastic resin foam sheet molded article according to claim 1 .

[0010] <15> <1> ~ <7> a heating step of heating the thermoplastic resin foam sheet according to any one of the above items; a molding step of sandwiching the thermoplastic resin foam sheet between a female mold and a male mold, The molding step is a method for producing a molded thermoplastic resin foam sheet, in which the thermoplastic resin foam sheet satisfying the following formula (I) is sandwiched between the female mold and the male mold and molded: (T A -30)℃≦(T S )℃≦(T A +30)℃ (I) [In the formula (I), T S represents the surface temperature of the thermoplastic resin foam sheet, and T A is the minimum value (E' A ) represents the temperature at which [Effects of the Invention]

[0011] The thermoplastic resin foam sheet of the present invention can improve moldability. Furthermore, by molding the thermoplastic resin foam sheet of the present invention, a thermoplastic resin foam sheet molded article having excellent impact resistance can be obtained. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing an example of a thermoplastic resin foam sheet according to an embodiment of the present invention. [Figure 2] FIG. 1 is a flow diagram showing an example of a manufacturing process for a plant-derived polyester resin. [Figure 3] FIG. 1 is a flow diagram showing an example of a manufacturing process for a plant-derived polyester resin. [Figure 4] FIG. 1 is a flow diagram showing an example of a manufacturing process for a plant-derived polyester resin. [Figure 5] 1 is a schematic diagram illustrating an example of a manufacturing apparatus for a thermoplastic resin foam sheet according to an embodiment of the present invention. [Figure 6] 1 is a perspective view of a thermoplastic resin foam sheet molded article according to an embodiment of the present invention. [Figure 7] FIG. 1 is a schematic diagram illustrating an example of an apparatus for producing a thermoplastic resin foam sheet molded article. [Figure 8]1 is a graph showing the results of measuring the storage modulus in Example 5. [Figure 9] 10 is a graph showing the results of measuring the storage modulus of Comparative Example 2. [Figure 10] 10 is a graph showing the measurement results of loss tangent in Example 5. [Figure 11] 1 is a DSC curve of Example 5. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this document, "~" indicates a range that includes both the upper and lower limits.

[0014] The thermoplastic resin foam sheet of the present invention (hereinafter sometimes simply referred to as "foam sheet") is obtained by foaming a thermoplastic resin composition (hereinafter sometimes simply referred to as "resin composition") containing a thermoplastic resin and a foaming agent. A non-foamed resin layer may be provided on a part or all of the surface of the foam sheet. For example, the foam sheet may be a single-layer sheet consisting of only a foam layer, or may have a non-foamed layer provided on one or both sides to form a laminated thermoplastic resin foam sheet (hereinafter simply referred to as a "laminated foam sheet"). Hereinafter, a single-layer sheet consisting of only a foam layer and a laminated foam sheet including such a single-layer sheet may be collectively referred to as a "thermoplastic resin foam sheet" (foam sheet). The single-layer structure consisting of only a foam layer includes a foam sheet consisting of one foam layer and a foam sheet consisting of two or more foam layers. Hereinafter, the present invention will be described with reference to embodiments thereof.

[0015] [Thermoplastic resin foam sheet] 1 is used as a raw sheet of a thermoplastic resin foamed sheet molded product (sometimes simply referred to as a "foamed sheet molded product"), a flat cushioning material, etc. Examples of foamed sheet molded products include containers such as thermoformed products, pressure-molded products, and deep-drawn molded products. 1 is a cross-sectional view of a foamed sheet 2 of this embodiment. The foamed sheet 2 is composed of one foamed layer 22. The thickness T of the foamed sheet 2 can be determined taking into consideration the intended use. For example, if the foamed sheet 2 is used to form a container, the thickness T is preferably 0.3 to 5.0 mm, more preferably 0.4 to 3.0 mm, and even more preferably 0.5 to 2.5 mm. When the thickness T is equal to or greater than the above lower limit, the impact resistance and rigidity of the container can be improved. When the thickness T is equal to or less than the above upper limit, the moldability of the foamed sheet 2 can be improved.

[0016] The foam layer 22 is a layer formed by foaming a thermoplastic resin composition. The thermoplastic resin composition contains a thermoplastic resin and a foaming agent. The foam layer 22 formed by foaming the thermoplastic resin composition has two or more bubbles in a matrix formed of the thermoplastic resin.

[0017] <Thermoplastic resin> The thermoplastic resin of the foam layer 22 contains a polyester resin and a polyetherimide resin. By containing both a polyester resin and a polyetherimide resin, the foam sheet 2 of the present embodiment can have improved heat resistance strength.

[0018] The number average molecular weight (Mn) of the thermoplastic resin is preferably 10,000 to 30,000, more preferably 15,000 to 25,000, and even more preferably 20,000 to 23,000. When the Mn of the thermoplastic resin is equal to or greater than the lower limit, the impact resistance can be further improved. When the Mn of the thermoplastic resin is equal to or less than the upper limit, the moldability can be further improved.

[0019] The mass average molecular weight (Mw) of the thermoplastic resin is preferably 50,000 to 200,000, more preferably 80,000 to 150,000, and even more preferably 100,000 to 140,000. When the Mw of the thermoplastic resin is equal to or greater than the above lower limit, the impact resistance can be further improved. When the Mw of the thermoplastic resin is equal to or less than the above upper limit, the moldability can be further improved.

[0020] The Z-average molecular weight Mz of the thermoplastic resin is preferably 300,000 to 700,000, more preferably 350,000 to 600,000, and even more preferably 400,000 to 550,000. When the Mz of the thermoplastic resin is equal to or greater than the lower limit, the impact resistance can be further improved. When the Mz of the thermoplastic resin is equal to or less than the upper limit, the moldability can be further improved.

[0021] The Mn, Mw and Mz of the thermoplastic resin can be measured by the method described in the examples. The Mn, Mw, and Mz of the thermoplastic resin can be adjusted by the Mn, Mw, and Mz of the polyester resin and polyetherimide resin, the composition of the thermoplastic resin, the type of crosslinking agent, the content of the crosslinking agent, the resin temperature during extrusion, and combinations of these.

[0022] <Polyester resin> Examples of polyester-based resins include polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polyethylene naphthalate resin (PEN), polyethylene furanoate resin (PEF), polybutylene naphthalate resin (PBN), polytrimethylene terephthalate resin (PTT), copolymers of terephthalic acid, ethylene glycol, and cyclohexanedimethanol, and mixtures thereof. Polyethylene terephthalate resin is preferred, and crystalline polyethylene terephthalate resin (C-PET) is more preferred. C-PET is a polyester-based resin whose acid component is terephthalic acid and whose glycol component is ethylene glycol. The polyester resin may be a polyester resin derived from a petrochemical product, a plant-derived polyester resin such as so-called bio-PET, or a mixture thereof. Examples of plant-derived polyester resins include polyethylene terephthalate resin, plant-derived polyethylene furanoate resin, and plant-derived polytrimethylene terephthalate resin. The polyester resin may also be made from recycled materials. These polyester resins may be used singly or in combination of two or more.

[0023] The plant-derived polyester resin will be described below. Plant-derived polyester resins are polymers derived from plant materials such as sugarcane and corn. "Derived from plant materials" includes polymers synthesized or extracted from plant materials. For example, "derived from plant materials" includes polymers obtained by polymerizing monomers synthesized or extracted from plant materials. "Monomers synthesized or extracted from plant materials" includes monomers synthesized using compounds synthesized or extracted from plant materials. Plant-derived polyester resins include those in which some of the monomers are "derived from plant materials."

[0024] Plant-derived polyester resins will be explained using PET and PEF as examples.

[0025] The synthesis reaction of PET is shown in equation (1). PET is synthesized by the dehydration reaction of n moles of ethylene glycol and n moles of terephthalic acid (Benzen-1,4-dicarboxylic acid). The stoichiometric mass ratio in this synthesis reaction is ethylene glycol:terephthalic acid = 30:70 (mass ratio).

[0026] [ka]

[0027] [In formula (1), n ​​is a stoichiometric coefficient (degree of polymerization) and is a number from 250 to 1,100.]

[0028] Ethylene glycol is produced industrially by oxidizing and hydrating ethylene, and terephthalic acid is produced industrially by oxidizing paraxylene. As shown in Figure 2, when ethylene is obtained by the dehydration reaction of plant-derived ethanol (bioethanol), and PET is synthesized from ethylene glycol (bioethanol-derived ethylene glycol) synthesized from this ethylene and terephthalic acid derived from petrochemicals, the PET produced is 30% plant-derived by mass. Furthermore, as shown in Figure 3, when paraxylene is obtained by the dehydration reaction of plant-derived isobutanol (bioisobutanol), and PET is synthesized from terephthalic acid synthesized from this paraxylene and ethylene glycol derived from bioethanol, the PET produced is 100% plant-derived PET by mass.

[0029] The synthesis reaction of PEF is shown in formula (2). PEF is synthesized by the dehydration reaction of n moles of ethylene glycol and n moles of 2,5-furandicarboxylic acid.

[0030] [ka]

[0031] [In formula (2), n is a stoichiometric coefficient (degree of polymerization) and is a number from 250 to 1,100.]

[0032] Furandicarboxylic acid (FDCA) can be obtained, for example, by dehydrating plant-derived fructose or glucose to obtain hydroxymethylfurfural (HMF), and then oxidizing the HMF. As shown in FIG. 4, when both FDCA and ethylene glycol are plant-derived, the produced PEF is 100% plant-derived by mass.

[0033] The content of the polyester resin relative to the total mass of the thermoplastic resins contained in the foamed sheet 2 is preferably 60 to 95 mass%, more preferably 65 to 90 mass%, and even more preferably 70 to 85 mass%. When the content of the polyester resin is equal to or greater than the lower limit, moldability can be further improved. When the content of the polyester resin is equal to or less than the upper limit, heat resistance strength can be further improved.

[0034] <Polyetherimide resin> The polyetherimide resin (PEI) is not particularly limited, but is preferably a polymer containing a cyclic imide group as a repeating unit and is preferably a polymer having melt moldability. The polyetherimide resin is a polyimide resin having a structural unit with an ether bond. The thermoplastic resin of this embodiment contains a polyetherimide resin, which improves compatibility with polyester resins. This further improves the moldability of the foam sheet 2.

[0035] Examples of polyetherimide resins include polymers described in U.S. Pat. No. 4,141,927, Japanese Patent No. 2,622,678, Japanese Patent No. 2,606,912, Japanese Patent No. 2,606,914, Japanese Patent No. 2,596,565, Japanese Patent No. 2,596,566, and Japanese Patent No. 2,598,478. The main chain of the polyetherimide resin may contain structural units other than cyclic imide, as long as the effects of the present invention are not impaired. Examples of structural units other than cyclic imide include aromatic, aliphatic, alicyclic, alicyclic ester units, and oxycarbonyl units. The polyetherimide resin may be made from recycled materials or may be a plant-derived resin such as bio-PEI. These polyetherimide resins may be used alone or in combination of two or more.

[0036] The polyetherimide resin is preferably, for example, a compound represented by the following formula (3).

[0037] [ka]

[0038] [In formula (3), R represents an aromatic group having 6 to 42 carbon atoms, R' represents at least one divalent organic group selected from the group consisting of divalent aromatic groups having 6 to 30 carbon atoms, aliphatic groups having 2 to 30 carbon atoms, and alicyclic groups having 4 to 30 carbon atoms, and at least one of R and R' has an ether bond. p represents a number representing a repeating unit.]

[0039] In formula (3), p is a number between 5 and 250, for example.

[0040] Polyetherimide resins can be prepared by conventionally known methods. For example, they can be obtained by dehydration condensation of either or both of a tetracarboxylic acid and its acid anhydride, which are raw materials from which R in formula (3) can be derived, with one or more compounds selected from the group consisting of aliphatic primary diamines and aromatic primary diamines, which are raw materials from which R' in formula (3) can be derived. Specific examples of methods for producing polyetherimide resins include a method in which a polyamic acid is obtained and then subjected to thermal ring closure. Other examples include a method in which a polyamic acid is chemically cyclized using an acid anhydride and a chemical ring closure agent such as pyridine or carbodiimide, and a method in which the tetracarboxylic acid anhydride and a diisocyanate from which R' can be derived are heated to decarboxylate and polymerize.

[0041] Examples of tetracarboxylic acids include pyromellitic acid, 1,2,3,4-benzenetetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,2',3,3'-biphenyltetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 2,2',3,3'-benzophenonetetracarboxylic acid, bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)methane, 1,1'-bis(2,3-dicarboxyphenyl)ethane, and 2,2'-bis(3,4-dicarboxyphenyl) Examples of suitable acid anhydrides include propane, 2,2'-bis(2,3-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)ether, bis(2,3-dicarboxyphenyl)ether, bis(3,4-dicarboxyphenyl)sulfone, bis(2,3-dicarboxyphenyl)sulfone, 2,3,6,7-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 2,2'-bis[(2,3-dicarboxyphenoxy)phenyl]propane, and acid anhydrides thereof.

[0042] Examples of diamines include benzidine, diaminodiphenylmethane, diaminodiphenylethane, diaminodiphenylpropane, diaminodiphenylbutane, diaminodiphenylether, diaminodiphenylsulfone, diaminodiphenylbenzophenone, o, m, p-phenylenediamine, tolylenediamine, xylenediamine, and aromatic primary diamines having hydrocarbon groups of these aromatic primary diamines as structural units, ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 2,2-dimethyl-1,3-propanediamine, 1,6-hexamethylenediamine, 1,8 Examples of the diamine include 1,9-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,4-cyclohexanedimethylamine, 2-methyl-1,3-cyclohexanediamine, isophoronediamine, and the like, as well as aliphatic and alicyclic primary diamines having a hydrocarbon group of these aliphatic and alicyclic primary diamines as a structural unit.

[0043] The content of the polyetherimide resin relative to the total mass of the thermoplastic resins contained in the foamed sheet 2 is preferably 5 to 40 mass%, more preferably 10 to 35 mass%, and even more preferably 15 to 30 mass%. When the content of the polyetherimide resin is equal to or greater than the lower limit, the heat resistance strength can be further improved. When the content of the polyetherimide resin is equal to or less than the upper limit, the moldability can be further improved.

[0044] The mass ratio of the foamed sheet 2, expressed as (polyester resin content) / (polyetherimide resin content) (hereinafter also referred to as "polyester / PEI ratio"), is preferably 1.5 to 19, more preferably 1.8 to 9, and even more preferably 2.3 to 5.7. When the polyester / PEI ratio is equal to or greater than the above lower limit, moldability can be further improved. When the polyester / PEI ratio is equal to or less than the above upper limit, heat resistance strength can be further improved.

[0045] [Method for measuring polyetherimide resin content] When it is necessary to determine the proportion of polyetherimide resin relative to the total mass of thermoplastic resins contained in foam sheet 2, the proportion of polyetherimide resin can be measured by the following method. For example, foam sheet 2 is sliced ​​along a direction (planar direction) perpendicular to the thickness direction of foam sheet 2 to prepare a thin sample (e.g., a sample with a thickness of 0.2 mm), and the proportion of polyetherimide resin in this sample can be measured as described below. An example of a method for measuring the proportion of polyetherimide resin relative to the total mass of a mixed resin of polyester resin and polyetherimide resin is shown below. Polyethylene terephthalate (PET) is used as the polyester resin.

[0046] The foamed sheet 2 is sliced ​​into 0.2 mm pieces along a direction (planar direction) perpendicular to the thickness direction from the surface of the foamed sheet 2 to prepare a measurement sample. The surface of the measurement sample is subjected to infrared spectroscopic analysis under the following conditions to obtain an infrared absorption spectrum. Measurement equipment: Thermo Scientific Nicolet iS10 Fourier transform infrared spectrophotometer and Thermo Scientific Smart-iTR single reflection horizontal ATR. ATR crystal: Diamond-attached KRS-5 (angle = 42°). ·Measurement method: Single reflection ATR method. ·Measurement wavenumber range: 4000cm -1 ~675cm -1 . Wavenumber dependence of measurement depth: Uncorrected. · Detector: Deuterated triglycine sulfate (DTGS) detector and KBr beam splitter. ·Resolution: 4cm -1 . -Number of accumulations: 16 (same for background measurement).

[0047] From the obtained infrared absorption spectrum chart, the peak heights of D1410 and D1778 are determined, and the content of polyetherimide resin is calculated using the following formula (p) obtained from a calibration curve prepared using a standard sample. Polyetherimide resin content (mass%) = 100 - {19.00ln(R) + 37.95} x 100 (p) R=D1410 / D1778

[0048] D1410 is a polyester resin derived wave number of 1410cm -1 ±5cm -1 The maximum absorbance difference (measured absorbance - baseline absorbance) from the baseline in the infrared absorption spectrum curve in the region of 1400 cm. The baseline is the wavenumber of 1400 cm in the infrared absorption spectrum curve. -1 ±5cm -1 The minimum absorption position at 1420 cm in the infrared absorption spectrum curve -1 ±5cm -1 The line connecting the lowest absorption position at D1778 is the wave number of polyetherimide resin, 1778 cm -1 ±5cm -1 The maximum absorbance difference (measured absorbance - baseline absorbance) from the baseline in the infrared absorption spectrum curve in the region of 1760 cm -1 ±5cm -1 The minimum absorption position at 1800 cm and the wavenumber in the infrared absorption spectrum curve -1 ±5cm -1 The line connecting the lowest absorption position at

[0049] [Creating standard samples] The standard samples were prepared as follows. First, a mixture was prepared by mixing polyester resin (PET: manufactured by Far Eastern New Century Co., Ltd., product name "CH-653"), polyetherimide resin (PEI: manufactured by SABIC Innovative Plastics, product name "Ultem 1000"), and crosslinking agent pyromellitic anhydride (PMDA) according to the formulation shown in Table 1. This mixture was then placed in a Labo Plastomill twin-screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., model: 2D15W, nozzle diameter: 15 mm, L / D = 17) and melt-kneaded at 350 °C to produce a resin composition. The molten resin was extruded through a nozzle die (diameter: 3.0 mm) attached to the front end of the Labo Plastomill twin-screw extruder. The extruded resin composition was immediately cooled in a cooling water bath. The cooled strand-shaped resin composition was then thoroughly drained and cut into small pellets approximately 2 mm long and 3 mm in diameter using a pelletizer to prepare standard samples (A to I). The compositions of the standard samples (A to I) are shown in Table 1.

[0050] [Table 1]

[0051] [Creating a calibration curve] The calibration curve is prepared as follows. The surfaces of the standard samples (A to I) are subjected to infrared spectroscopic analysis under the following conditions to obtain infrared absorption spectra. Measurement equipment: Thermo Scientific Nicolet iS10 Fourier transform infrared spectrophotometer and Thermo Scientific Smart-iTR single-reflection horizontal ATR. ATR crystal: Diamond-attached KRS-5 (angle = 42°). ·Measurement method: Single reflection ATR method. ·Measurement wavenumber range: 4000cm -1 ~675cm -1 . Wavenumber dependence of measurement depth: Uncorrected. · Detector: Deuterated triglycine sulfate (DTGS) detector and KBr beam splitter. ·Resolution: 4cm-1 . -Number of accumulations: 16 (same for background measurement). Number of measurements: 10

[0052] From the infrared absorption spectrum chart obtained in each measurement, data processing is performed in the same manner as in the method for measuring the content ratio of polyetherimide-based resin described above, the peak heights of D1410 and D1778 are determined, and the absorbance ratio (R = D1410 / D1778) is calculated. The blending ratio of polyester-based resin against the absorbance ratio of each standard sample (A to I) is plotted, and the logarithmic approximation formula in the plot is used as the calibration curve.

[0053] The thermoplastic resin contained in the foam sheet 2 may contain recycled materials. Either the polyester resin or the polyetherimide resin may contain recycled materials, or both the polyester resin and the polyetherimide resin may contain recycled materials. A part or all of the polyester resin may be recycled polyester resin materials, or a part or all of the polyetherimide resin may be recycled polyetherimide resin materials. Examples of recycled raw materials include the following raw materials: 1) Foamed sheets or foamed sheet moldings are crushed to obtain flake-like resin, which is remelted in an extruder, extruded from a nozzle die into strands, and pelletized after cooling. 2) Recycled PET made by crushing PET bottles to obtain flake-like resin, which is remelted in an extruder, extruded into strands through a nozzle mold, cooled, and then pelletized.

[0054] <Other resins> The foam sheet 2 is substantially free of thermosetting resin. "Substantially free" means that the foam sheet 2 contains no thermosetting resin at all or contains only a small amount that does not affect the quality of the foam sheet 2. The content of the thermosetting resin in the foam sheet 2 is preferably 5 parts by mass or less, more preferably 2 parts by mass or less, even more preferably 1 part by mass or less, and most preferably 0 part by mass, per 100 parts by mass of the thermoplastic resin.

[0055] The thermoplastic resin may include a thermoplastic resin (other thermoplastic resin) other than the polyester resin and the polyetherimide resin, such as a polyolefin resin (e.g., polyethylene or polypropylene), a polystyrene resin, a polyphenylene ether resin, a polyamide resin, a polycarbonate resin, a polyarylate resin, a polyphenylsulfone resin, a polysulfone resin, or a polyethersulfone resin.

[0056] The combined proportion of the polyester resin and the polyetherimide resin relative to the total mass of the thermoplastic resins is preferably 90 mass% or more, more preferably 95 mass% or more, even more preferably 98 mass% or more, and most preferably 100 mass%. When the combined proportion of the polyester resin and the polyetherimide resin is equal to or more than the lower limit, the heat resistance strength of the foamed sheet 2 can be further increased.

[0057] <Physical Properties> The storage modulus of foam sheet 2, as determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz, is a minimum value (E' A ) The storage modulus of the foam sheet 2 is determined by solid viscoelasticity measurement (DMA measurement).

[0058] [Storage modulus] The DMA measurement device is an "EXSTRAR DMS6100" viscoelasticity spectrometer manufactured by SII Nano Technology Co., Ltd., and a sample (test piece) approximately 40 mm in length and 10 mm in width is cut out from the foam sheet 2. The dimensions of the test piece are measured using a "DIGIMATIC" CD-15 type manufactured by Mitutoyo Corporation. The DMA measurement conditions are as follows:

[0059] [Measurement conditions] Mode: Tension control mode. Atmosphere: Nitrogen atmosphere. Frequency: 1Hz ·Heating rate: 5℃ / min. ·Measurement temperature: 30℃~300℃. Chuck spacing: 20mm. ·Distortion amplitude: 5μm. ·Minimum tension: 100mN. Tension Gain: 1.5 Initial force amplitude: 100mN.

[0060] Minimum storage modulus (E' A ) can be determined from the curve of change in storage modulus versus temperature obtained by DMA measurement using analysis software provided with the device. Specifically, for each measurement point of storage modulus, the storage modulus (y-axis) is plotted against the temperature (x-axis), and when the slope a of the linear approximation equation (y=ax+b) (where a is the slope of the linear approximation equation and b is the intercept of the linear approximation equation) between three adjacent measurement points is in the range of a<0 to a>0, the foamed sheet 2 is said to have reached a "minimum value (E' A When a plurality of minimum values ​​are observed in the change curve, the minimum value with the smallest storage modulus value is determined as the minimum value (E' A ) will be adopted. The foam sheet 2 has a minimum storage modulus (E' A ), the foamed sheet 2 can maintain a suitable flexibility when heated, and the moldability can be further improved. When the change curve is a monotonically decreasing curve in the measurement temperature range of 30 to 200°C, the foamed sheet 2 has a minimum storage modulus (E' A ) is not available.

[0061] The minimum value of the storage modulus of foam sheet 2 (E' A The minimum value of the storage modulus (E') is preferably 1.0 to 10.0 MPa, more preferably 2.0 to 9.0 MPa, and even more preferably 3.0 to 8.0 MPa. A When the minimum value of the storage modulus (E') is equal to or greater than the above lower limit, the dimensional stability upon heating and the heat resistance strength can be further improved. A ) is equal to or less than the above upper limit, the moldability can be further improved. The minimum value of the storage modulus of foam sheet 2 (E' A) can be adjusted by the molecular weight of the thermoplastic resin (number average molecular weight Mn, mass average molecular weight Mw, Z average molecular weight Mz), the composition of the thermoplastic resin, the resin temperature during extrusion, the crystallinity of the foamed sheet 2, and a combination thereof.

[0062] The storage modulus of foam sheet 2 at 30°C was determined as E' 30 In this case, E' 30 / E' A The ratio (E' 30 / E' A The ratio (E') is preferably 40 to 400, more preferably 50 to 300, and even more preferably 60 to 200. 30 / E' A When the ratio (E') is equal to or greater than the lower limit, the moldability can be further improved. 30 / E' A ) is equal to or less than the above upper limit, the heat resistance strength can be further increased.

[0063] The minimum value of the storage modulus of the foam sheet 2 in the measurement temperature range of 30 to 200°C is E' B In this case, E' 30 / E' B The ratio (E' 30 / E' B The ratio (E') is preferably 40 to 400, more preferably 50 to 300, and even more preferably 60 to 200. 30 / E' B When the ratio (E') is equal to or greater than the lower limit, the moldability can be further improved. 30 / E' B ) is equal to or less than the upper limit, the dimensional stability under heating and the heat resistance strength can be further improved. In addition, E' B is E' A It may be the same as or different from.

[0064] The temperature (t') at which the loss tangent (tanδ) becomes maximum when measured by solid viscoelasticity measurement of foam sheet 2 at a heating rate of 5°C / min and a frequency of 1 Hz. MAX ) is preferably 80 to 130°C, more preferably 90 to 125°C, and even more preferably 100 to 120°C, within the measurement temperature range of 30 to 200°C.MAX When t' is equal to or greater than the lower limit, the temperature at which the foamed sheet 2 softens becomes high, and the heat resistance strength can be further improved. MAX When is equal to or less than the above upper limit, the temperature at which the foamed sheet 2 softens does not become excessively high, and the moldability can be further improved. The temperature (t') at which the loss tangent (tanδ) is maximum MAX ) can be determined using the analytical software provided with the device under the same conditions as in the DMA measurement of the storage modulus described above.

[0065] The glass transition temperature (Tg) of the foamed sheet 2 is, for example, preferably 80 to 130°C, more preferably 85 to 125°C, and even more preferably 90 to 120°C. When Tg is equal to or higher than the above lower limit, the heat resistance strength and dimensional stability under heat can be further improved. When Tg is equal to or lower than the above upper limit, the molding cycle can be shortened to increase productivity, and moldability can be further improved. The glass transition temperature (Tg) of the foam sheet 2 is determined by heat flux differential scanning calorimetry (DSC) measurement at a heating rate of 10°C / min. The glass transition temperature (Tg) of the foamed sheet 2 can be considered to be the same as the glass transition temperature (Tg) of the thermoplastic resin that constitutes the foamed sheet 2.

[0066] The absolute value of the difference between the amount of heat absorbed and the amount of heat generated in the foamed sheet 2 (endothermic / heat-generating difference) is preferably 3 to 21 J / g, more preferably 4 to 15 J / g, and even more preferably 5 to 10 J / g. When the endothermic / heat-generating difference is equal to or greater than the lower limit, the degree of crystallinity is increased, and the heat-resistant strength and dimensional stability during heating can be further improved. When the endothermic / heat-generating difference is equal to or less than the upper limit, the degree of crystallinity does not increase too much, and moldability can be further improved. The endothermic / heat-generating difference is the difference between the endothermic amount and the heat-generating amount determined by DSC measurement at a heating rate of 10°C / min. The endothermic / heat-generating difference in foamed sheet 2 can be considered to be the same as the endothermic / heat-generating difference of the thermoplastic resin constituting foamed sheet 2.

[0067] The melting point of the foamed sheet 2 is preferably 230 to 270°C, more preferably 235 to 260°C, and even more preferably 245 to 255°C. When the melting point of the foamed sheet 2 is equal to or higher than the lower limit, the heat resistance strength and dimensional stability under heat can be further improved. When the melting point of the foamed sheet 2 is equal to or lower than the upper limit, the molding cycle can be shortened to increase productivity and moldability. The melting point of the foamed sheet 2 can be considered to be the same as the melting point of the thermoplastic resin that constitutes the foamed sheet 2.

[0068] <Foaming agent> Examples of blowing agents include saturated aliphatic hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane, and hexane, ethers such as dimethyl ether, chlorofluorocarbons such as methyl chloride, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, and monochlorodifluoromethane, carbon dioxide, and nitrogen, with dimethyl ether, propane, normal butane, isobutane, carbon dioxide, and nitrogen being preferred. These blowing agents may be used alone or in combination of two or more.

[0069] The content of the foaming agent is not particularly limited, but is preferably, for example, 0.1 to 12 parts by mass relative to 100 parts by mass of the thermoplastic resin.

[0070] <Optional ingredients> The foamed sheet 2 of the present embodiment may contain other components (optional components) in addition to the thermoplastic resin and the foaming agent. Optional components include a cell regulator, a stabilizer, an ultraviolet absorber, a colorant, an antioxidant, a crystallization accelerator, a lubricant, a crosslinking agent, a surfactant, a shrinkage inhibitor, a flame retardant, and an anti-deterioration agent.

[0071] Examples of the crosslinking agent include acid dianhydrides such as pyromellitic anhydride, polyfunctional epoxy compounds, oxazoline compounds, oxazine compounds, etc. By blending a crosslinking agent into the thermoplastic resin composition, cell breakage during foaming can be suppressed, and the open cell ratio can be further reduced. The content of the crosslinking agent is, for example, preferably 0.08 to 0.80 parts by mass, more preferably 0.10 to 0.40 parts by mass, and even more preferably 0.15 to 0.30 parts by mass, relative to 100 parts by mass of the thermoplastic resin. When the content of the crosslinking agent is equal to or greater than the above-mentioned lower limit, the molecular weight (number average molecular weight (Mn), mass average molecular weight (Mw), Z-average molecular weight (Mz)) of the thermoplastic resin can be increased, and impact resistance can be further improved. When the content of the crosslinking agent is equal to or less than the above-mentioned upper limit, an increase in the molecular weight of the thermoplastic resin can be suppressed, and moldability can be further improved.

[0072] The cell adjusting agent is, for example, a mixture of inorganic powder such as talc, silica, etc. These cell adjusting agents increase the closed cell rate of the foamed layer 22, making it easier to form the foamed layer 22. The content of the cell adjusting agent is preferably, for example, 0.2 to 5 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

[0073] Examples of the stabilizer include calcium zinc-based heat stabilizers, tin-based heat stabilizers, and lead-based heat stabilizers. The content of the stabilizer is preferably, for example, 1 part by mass or less with respect to 100 parts by mass of the thermoplastic resin.

[0074] Examples of the ultraviolet absorber include a cesium oxide-based ultraviolet absorber and a titanium oxide-based ultraviolet absorber. The content of the ultraviolet absorber is preferably, for example, 1 part by mass or less with respect to 100 parts by mass of the thermoplastic resin.

[0075] Examples of antioxidants include cerium oxide, cerium oxide / zirconia solid solution, cerium hydroxide, carbon, carbon nanotubes, titanium oxide, and fullerene. The content of the antioxidant is preferably, for example, 1 part by mass or less with respect to 100 parts by mass of the thermoplastic resin.

[0076] Examples of colorants include titanium oxide, carbon black, titanium yellow, iron oxide, ultramarine, cobalt blue, calcined pigments, metallic pigments, mica, pearl pigments, zinc oxide, precipitated silica, and cadmium red. When the foamed sheet 2 of the present embodiment is used for food containers, it is preferable to select a colorant registered with the Hygienic Council from among the above colorants. The content of the colorant is preferably, for example, 2 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

[0077] Examples of the crystallization accelerator include silicates, carbon, metal oxides, etc. Examples of silicates include talc, which is hydrous magnesium silicate. Examples of carbon include carbon black, carbon nanofiber, carbon nanotubes, carbon nanohorns, activated carbon, graphite, graphene, coke, mesoporous carbon, glassy carbon, hard carbon, and soft carbon. Examples of carbon black include furnace black, acetylene black, ketjen black, and thermal black. Examples of metal oxides include zinc oxide and titanium oxide. The content of the crystallization accelerator is preferably, for example, 3 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

[0078] The above-mentioned optional components may each be used alone or in combination of two or more. The total amount of the optional components contained in the foamed layer 22 is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, based on the total mass of the foamed layer 22.

[0079] <Physical properties> The open cell ratio of the foamed layer 22 is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less. When the open cell ratio of the foamed layer 22 is equal to or less than the above upper limit, the impact resistance and moldability of the foamed sheet 2 can be further improved. The open cell ratio of the foamed layer 22 can be determined by the method described in JIS K7138:2006 "Rigid foamed plastics - Determination of open cell ratio and closed cell ratio."

[0080] The basis weight of the foam layer 22 is, for example, 50 to 900 g / m 2 is preferred, and 100 to 700 g / m 2 More preferably, 150 to 500 g / m 2is more preferable. When the basis weight of the foam layer 22 is equal to or greater than the above lower limit, the impact resistance of the foamed sheet 2 can be further improved. When the basis weight of the foam layer 22 is equal to or less than the above upper limit, the foamed sheet 2 can be made lighter. In addition, when the basis weight of the foam layer 22 is equal to or less than the above upper limit, the heating time during thermoforming is not too long, and the productivity of the foamed sheet molded article can be further improved.

[0081] The basis weight of the foam layer 22 can be measured by the following method. Excluding 20 mm from both ends in the width direction of the foam layer 22, five or more 10 cm x 10 cm pieces are cut out at equal intervals in the width direction, and the mass (g) of each piece is measured to the nearest 0.001 g. The average mass (g) of each piece is calculated as 1 m 2 The value converted into the mass per unit area is used as the basis weight (g / m) of the foam layer 22. 2 )

[0082] The apparent density of the foam layer 22 is, for example, 0.050 to 0.666 g / cm 3 is preferable, and 0.066 to 0.500 g / cm 3 More preferably, 0.100 to 0.400 g / cm 3 When the apparent density of foamed layer 22 is equal to or greater than the above lower limit, the heat insulating property and impact resistance of foamed sheet 2 can be further improved. When the apparent density of foamed layer 22 is equal to or less than the above upper limit, the weight of foamed sheet 2 can be further reduced.

[0083] The expansion ratio of the foam layer 22 is, for example, preferably 2 to 20 times, more preferably 3 to 15 times, and even more preferably 3.5 to 10 times. When the expansion ratio of the foam layer 22 is equal to or greater than the above lower limit, the heat insulating properties and impact resistance of the resin foam molded article can be further improved. When the expansion ratio of the foam layer 22 is equal to or less than the above upper limit, the moldability of the foam sheet 2 can be further improved.

[0084] The average cell diameter of foamed layer 22 is, for example, preferably 80 to 1000 μm, more preferably 150 to 750 μm, and even more preferably 200 to 500 μm. When the average cell diameter of foamed layer 22 is equal to or greater than the above lower limit, the impact resistance of foamed sheet 2 can be further improved. When the average cell diameter of foamed layer 22 is equal to or less than the above upper limit, the surface smoothness of foamed sheet 2 can be further improved.

[0085] [Foam sheet manufacturing method] The foamed sheet 2 is produced by a conventionally known production method. The foamed sheet 2 can be produced, for example, by the following method. 5 is an apparatus for producing a foamed sheet by extrusion molding. The apparatus 1 includes an extruder 10, a foaming agent supply source 18, a circular die 20, a mandrel 30, and two winders 40. The extruder 10 is a so-called tandem extruder. The extruder 10 includes a first extrusion section 11 and a second extrusion section 12 connected to the first extrusion section 11 via a pipe 16. The first extrusion section 11 includes a hopper 14. A blowing agent supply source 18 is connected to the first extrusion section 11. A circular die 20 is connected to the second extrusion section 12. A mandrel 30 equipped with a cutter 32 is provided downstream of the circular die 20. A cooling fan (not shown) is provided between the circular die 20 and the mandrel 30. The extruder 10 of the production apparatus 1 may be an extruder other than a tandem extruder. For example, the extruder 10 may be an extruder in which a circular die 20 is connected to the first extrusion section 11. The extruder 10 of the production apparatus 1 may be a single-screw extruder or a multi-screw extruder such as a twin-screw extruder.

[0086] The raw materials constituting the foam layer are fed from a hopper 14 into the first extrusion section 11. The raw materials fed from the hopper 14 include a resin constituting the foam layer, a group of inorganic particles, and optional components that are blended as needed. In the first extrusion section 11, the raw materials are mixed while being heated to a given temperature to form a resin melt, and a foaming agent is supplied to the first extrusion section 11 from a foaming agent supply source 18, and the foaming agent is mixed with the resin melt to form a resin composition. The heating temperature is appropriately determined in consideration of the type of resin, etc., so long as the resin melts and the optional components are not denatured.

[0087] The glass transition temperature (Tg) of the polyester resin (raw polyester resin) blended into the thermoplastic resin composition is preferably 50 to 100°C, more preferably 60 to 90°C, and even more preferably 70 to 85°C. When the Tg of the raw polyester resin is equal to or greater than the above lower limit, the heat resistance strength and dimensional stability under heat can be further improved. When the Tg of the raw polyester resin is equal to or less than the above upper limit, the molding cycle can be shortened to increase productivity and further improve moldability. Note that "moldability" refers to, for example, the ability of a foamed sheet to conform to the mold cavity and approximate a desired shape when thermoforming a foamed sheet between molds; the closer it approaches the desired shape, the "better" the moldability.

[0088] The melting point of the raw material polyester resin is preferably 230 to 270°C, more preferably 240 to 260°C, and even more preferably 245 to 255°C. If the melting point is equal to or higher than the lower limit, the heat resistance strength and dimensional stability under heat can be further improved. If the melting point is equal to or lower than the upper limit, the molding cycle can be shortened to increase productivity and further improve moldability.

[0089] The intrinsic viscosity (IV value) of the raw polyester resin is preferably 0.5 to 1.5, more preferably 0.6 to 1.3, and even more preferably 0.7 to 1.2. When the IV value of the raw polyester resin is equal to or greater than the lower limit, cell breakage during foaming can be suppressed, further reducing the open cell ratio. When the IV value of the raw polyester resin is equal to or less than the upper limit, the density can be reduced, the surface can be made smoother, and the appearance can be made more beautiful. The IV value of the raw material polyester resin can be measured by the method of JIS K7367-5:2000.

[0090] The number average molecular weight (Mn) of the raw polyester resin is preferably 10,000 to 50,000, more preferably 15,000 to 45,000, and even more preferably 20,000 to 40,000. When the Mn of the raw polyester resin is equal to or greater than the lower limit, the impact resistance can be further improved. When the Mn of the raw polyester resin is equal to or less than the upper limit, the moldability can be further improved.

[0091] The mass average molecular weight (Mw) of the raw polyester resin is preferably 50,000 to 150,000, more preferably 60,000 to 140,000, and even more preferably 70,000 to 130,000. When the Mw of the raw polyester resin is equal to or greater than the lower limit, the impact resistance can be further improved. When the Mw of the raw polyester resin is equal to or less than the upper limit, the moldability can be further improved.

[0092] The Z-average molecular weight (Mz) of the raw polyester resin is preferably 60,000 to 250,000, more preferably 80,000 to 200,000, and even more preferably 90,000 to 180,000. When the Mz of the raw polyester resin is equal to or greater than the lower limit, the impact resistance can be further improved. When the Mz of the raw polyester resin is equal to or less than the upper limit, the moldability can be further improved. The Mn, Mw and Mz of the raw material polyester resin can be measured in the same manner as the Mn, Mw and Mz of the thermoplastic resin.

[0093] The glass transition temperature (Tg) of the polyetherimide resin (raw material polyetherimide resin) blended into the thermoplastic resin composition is preferably 190 to 240°C, more preferably 200 to 230°C, and even more preferably 210 to 220°C. If the Tg of the raw material polyetherimide resin is equal to or greater than the above lower limit, the heat resistance strength and heated dimensional stability can be further improved. If the Tg of the raw material polyetherimide resin is equal to or less than the above upper limit, the molding cycle can be shortened to increase productivity and further improve moldability.

[0094] The melt flow rate (MFR) of the raw material polyetherimide resin is preferably 3 to 30 g / 10 min, more preferably 5 to 25 g / 10 min, and even more preferably 7 to 20 g / 10 min. If the MFR is equal to or greater than the lower limit, the molding cycle can be shortened, increasing productivity and further improving moldability. If the MFR is equal to or less than the upper limit, the impact resistance can be further improved. In this specification, the MFR of the raw material polyetherimide resin is a value measured at 337°C and 6.6 kgf, and can be measured in accordance with the method described in ASTM D1238.

[0095] The number average molecular weight (Mn) of the raw material polyetherimide resin is preferably 10,000 to 50,000, more preferably 15,000 to 30,000, and even more preferably 20,000 to 25,000. When the Mn of the raw material polyetherimide resin is equal to or greater than the lower limit, the impact resistance can be further improved. When the Mn of the raw material polyetherimide resin is equal to or less than the upper limit, the moldability can be further improved.

[0096] The mass average molecular weight (Mw) of the raw material polyetherimide resin is preferably 20,000 to 80,000, more preferably 30,000 to 70,000, and even more preferably 40,000 to 60,000. When the Mw of the raw material polyetherimide resin is equal to or greater than the lower limit, the impact resistance can be further improved. When the Mw of the raw material polyetherimide resin is equal to or less than the upper limit, the moldability can be further improved.

[0097] The Z-average molecular weight (Mz) of the raw material polyetherimide resin is preferably 40,000 to 120,000, more preferably 50,000 to 100,000, and even more preferably 60,000 to 90,000. When the Mz of the raw material polyetherimide resin is equal to or greater than the above lower limit, the impact resistance can be further improved. When the Mz of the raw material polyetherimide resin is equal to or less than the above upper limit, the moldability can be further improved. The Mn, Mw and Mz of the raw material polyetherimide resin can be measured in the same manner as the Mn, Mw and Mz of the thermoplastic resin.

[0098] The thermoplastic resin composition is supplied from the first extrusion section 11 through a pipe 16 to the second extrusion section 12, where it is further mixed. Thereafter, the resin composition is cooled to a desired temperature and then introduced into a resin flow path in a circular die 20. The thermoplastic resin composition guided into the resin flow path is extruded through a circular die 20, and the foaming agent causes foaming to form a cylindrical foamed sheet 2. The cylindrical foamed sheet 2 is guided to the mandrel 30 while being blown with cooling air sent from a cooling fan. The cylindrical foamed sheet 2 passes over the outer surface of the mandrel 30, is cooled to a desired temperature, and is cut into two pieces by a cutter 32 to form the foamed sheet 2. The foamed sheet 2 is wrapped around guide rolls 42 and 44, respectively, and is wound up by a winder 40 to form the foamed sheet roll 4.

[0099] The resin temperature during extrusion (the temperature of the thermoplastic resin composition before being introduced into the circular die 20) is preferably 285 to 315°C, more preferably 290 to 310°C, and even more preferably 295 to 305°C. If the resin temperature during extrusion is equal to or higher than the lower limit, excessive molecular weight increase can be suppressed and moldability can be further improved. If the resin temperature during extrusion is equal to or lower than the upper limit, excessive molecular weight decrease can be suppressed and impact resistance can be further improved.

[0100] [Thermoplastic resin foam sheet molding] The thermoplastic resin foamed sheet molded article (foamed sheet molded article, hereinafter also simply referred to as "molded article") of this embodiment is obtained by molding a foam sheet 2. Examples of foamed sheet molded articles include containers such as food trays, cushioning materials used in industrial parts such as electrical appliances or automobiles, packaging materials, structural members, and heat insulating materials. As an example of the foamed sheet molded article, a container will be described with reference to the drawings.

[0101] The container 100 in Fig. 6 comprises a cylindrical container body 110 with a bottom, which has a bottom wall that is circular in plan view and a side wall that stands upright from the periphery of the bottom wall, and a lip portion 114 that protrudes outward is formed on the periphery of an opening 112. The container body 110 narrows from the opening 112 toward the bottom wall. The lip portion 114 has a semicircular cross section. In this embodiment, the container 100 is constituted by the container body 110.

[0102] The opening diameter R1 of the container body 110 is determined taking into consideration the use of the container 100, and is set to 50 to 100 mm, for example, if the container is a beverage container. The height H1 of the container body 110 is determined taking into consideration the use of the container 100, and is set to 70 to 200 mm, for example, if the container is a beverage container. The drawing ratio, expressed as height H1 (mm) / opening diameter R1 (mm), is determined taking into consideration the use of the container 100, etc. The drawing ratio is preferably 0.5 to 2.0, and more preferably 1.0 to 1.8, for example. If the drawing ratio is equal to or greater than the above lower limit, the container can be easily used. If the drawing ratio is equal to or less than the above upper limit, cracks and wrinkles are less likely to occur during molding, and moldability can be further improved. The angle (inclination angle) θ of the side wall portion relative to the bottom wall portion is determined taking into consideration the use of the container 100. For example, for a beverage container, it is set to 80 to 88°. If the angle is equal to or greater than the above lower limit, the design of the beverage container can be improved, and if the angle is equal to or less than the above upper limit, the container body 110 can be formed more easily. The thickness of the side wall of the container body 110 is not particularly limited, but is preferably 0.3 to 3 mm, for example. If the thickness of the side wall is equal to or greater than the above lower limit, the impact resistance of the container 100 can be further improved. If the thickness of the side wall is equal to or less than the above upper limit, the container body 110 can be more easily molded.

[0103] Although the container 100 of this embodiment has a perfect circular shape in plan view, the present invention is not limited to this. The shape of the container in plan view may be elliptical or polygonal, such as rectangular.

[0104] The container 100 of this embodiment is obtained by molding a foamed sheet 2. That is, the container 100 has bubbles in a thermoplastic resin. The container 100 has a minimum storage modulus (E') determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz. B The minimum storage modulus (E') is 1.0 to 10.0 MPa, preferably 2.0 to 9.0 MPa, and more preferably 3.0 to 8.0 MPa, in the measurement temperature range of 30 to 200°C. B If the minimum value of the storage modulus (E') is equal to or greater than the above lower limit, the heat resistance strength can be further increased. B ) is equal to or less than the above upper limit, the impact resistance can be further improved. The minimum storage modulus (E') of the container 100 B The storage modulus of the foam sheet 2 is determined by measuring the solid viscoelasticity. A ) is the same as when The minimum storage modulus (E') of the container 100 B ) can be adjusted by the molecular weight of the thermoplastic resin (number average molecular weight Mn, mass average molecular weight Mw, Z average molecular weight Mz), the composition of the thermoplastic resin, the crystallinity of the container 100, and a combination thereof.

[0105] The storage modulus of the container 100 at 30°C is E' 30 In this case, E' 30 / E' B The ratio (E' 30 / E' B The ratio (E') is preferably 40 to 200, more preferably 45 to 150, and even more preferably 50 to 100. 30 / E' B If the ratio (E') is equal to or greater than the lower limit, the impact resistance can be further improved. 30 / E' B ) is equal to or less than the above upper limit, the heat resistance strength can be further increased.

[0106] The temperature (t') at which the loss tangent (tanδ) is maximized by measuring the solid viscoelasticity of the container 100 at a heating rate of 5°C / min and a frequency of 1 Hz. MAX) is preferably 80 to 130°C, more preferably 85 to 128°C, and even more preferably 95 to 125°C, within the measurement temperature range of 30 to 200°C. MAX If t' is equal to or greater than the lower limit, the temperature at which the container 100 softens becomes higher, and the heat resistance strength can be further improved. MAX If is equal to or less than the above upper limit, the impact resistance can be further improved. The temperature (t') at which the loss tangent (tanδ) is maximum MAX ) can be determined using the analytical software provided with the device under the same conditions as in the DMA measurement of the storage modulus described above.

[0107] The glass transition temperature (Tg) of the container 100 is, for example, preferably 80 to 130°C, more preferably 85 to 125°C, and even more preferably 90 to 120°C. If Tg is equal to or higher than the above lower limit, the heat resistance strength can be further improved. If Tg is equal to or lower than the above upper limit, the impact resistance can be further improved.

[0108] The absolute value of the difference between the amount of heat absorbed and the amount of heat generated in the container 100 (endothermic / heat generating difference) is preferably 7 to 28 J / g, more preferably 8 to 20 J / g, and even more preferably 10 to 15 J / g. If the endothermic / heat generating difference is equal to or greater than the lower limit, the crystallinity increases, and the heat resistance strength can be further improved. If the endothermic / heat generating difference is equal to or less than the upper limit, the crystallinity does not increase too much, and the impact resistance can be further improved. The endothermic / heat-generating difference is the difference between the endothermic amount and the heat-generating amount determined by DSC measurement at a heating rate of 10°C / min. The endothermic / heat-generating difference in the container 100 can be considered to be the same as the endothermic / heat-generating difference of the thermoplastic resin that constitutes the container 100 .

[0109] [Method of manufacturing foam sheet molding] The container 100 can be manufactured, for example, by heating the foamed sheet 2 and sandwiching it between a female mold (cavity) and a male mold (core) to form the container (thermoforming method). An example of a molding apparatus used in the method for manufacturing the container 100 is shown in FIG. The molding apparatus 200 in FIG. 7 includes a shaft 221, a pair of supply rollers 222, a transport conveyor 223, a preheating section 203, a heating mold 204, a cooling mold 205, and a die-cutting machine 224. The preheating section 203 has an upper heating plate 231 and a lower heating plate 232 facing the upper heating plate 231. The preheating section 203 may be a heating furnace instead of the combination of the upper heating plate 231 and the lower heating plate 232. The heating mold 204 has a heating cavity 241 and a heating core 242. The heating mold 204 may be a vacuum forming machine, a pressure forming machine, or the like. The cooling mold 205 has a cooling cavity 251 and a cooling core 252 . The heating cavity 241 and the cooling cavity 251 have the same shape, and the heating core 242 and the cooling core 252 have the same shape.

[0110] First, the foam sheet roll 4 is attached to the shaft 221. The foam sheet 2 is unwound from the foam sheet roll 4, and the pair of supply rollers 222 intermittently transport the foam sheet 2 in the X direction. The preheating section 203 heats the transported foam sheet 2 (preheating step). The surface temperature (T S The surface temperature (T S When the surface temperature (T S ) is equal to or less than the upper limit, an excessive increase in the crystallinity of the foamed sheet 2 can be suppressed, and the moldability can be further improved. The heating time in the preheating step is preferably 5 to 90 seconds, more preferably 7 to 60 seconds, and even more preferably 10 to 30 seconds.

[0111] Next, the heated mold 204 sandwiches the foamed sheet 2 between the heating cavity 241 and the heating core 242, and heats and molds the foamed sheet 2 (molding step). The temperature (heating temperature) of the heated mold in the molding step is preferably 30 to 240°C, more preferably 35 to 200°C, and even more preferably 40 to 180°C. When the heating temperature is equal to or higher than the lower limit, the foamed sheet 2 is softened and pressed into the heated cavity 241, thereby improving moldability. When the heating temperature is equal to or lower than the upper limit, the mold release properties of the foamed sheet molded article are improved. The molding time in the molding step is preferably 1 to 10 seconds, more preferably 2 to 8 seconds, and even more preferably 3 to 7 seconds. When the molding time is equal to or higher than the lower limit, the foamed sheet 2 is softened and pressed into the heated cavity 241, thereby improving moldability. In addition, the dimensional stability upon heating is improved. When the molding time is equal to or lower than the upper limit, the time per cycle is shortened, thereby improving productivity.

[0112] In the molding step, it is preferable to sandwich the foamed sheet 2 satisfying the following formula (I) between the heating cavity 241 and the heating core 242 and mold it. (T A -30)℃≦(T S )℃≦(T A +30)℃ (I) In formula (I), T S represents the surface temperature of the thermoplastic resin foam sheet, and T A is the minimum value (E' A ) represents the temperature at which Surface temperature (T S ) and the temperature T A However, by carrying out the molding process so as to satisfy the relationship of the above formula (I), the flexibility of the foamed sheet 2 is maintained at an appropriate level, and the moldability is further improved.

[0113] After the molding step, the heated mold 204 may further heat the foamed sheet 2 therein (heat setting step). The heat setting step increases the crystallinity of the foamed sheet 2, further improving its dimensional stability upon heating. The temperature of the heated mold in the heat setting step (heat setting temperature) is preferably 130 to 240°C, more preferably 140 to 220°C, and even more preferably 150 to 200°C. When the heat setting temperature is equal to or higher than the lower limit, the crystallinity of the foamed sheet 2 is increased, further improving its dimensional stability upon heating. When the heat setting temperature is equal to or lower than the upper limit, the mold releasability of the foamed sheet molding is improved. The heating time in the heat setting step (heat setting time) is preferably 3 to 90 seconds, more preferably 5 to 60 seconds, and even more preferably 7 to 50 seconds. When the heat setting time is equal to or higher than the lower limit, the crystallinity of the foamed sheet 2 is increased, further improving its dimensional stability upon heating. When the heat setting time is equal to or lower than the upper limit, the time per cycle is shortened, thereby improving productivity. Even if the heat setting step is omitted, the foamed sheet 2 of the present embodiment does not lose its heat resistance strength and does not significantly impair its dimensional stability under heat.

[0114] Next, the heating mold 203 is opened, and the foamed sheet 2 molded into a desired shape is transferred to the position of the cooling mold 205, where the foamed sheet 2 is sandwiched between the cooling cavity 251 and the cooling core 252 (cooling step). The cooling step may be omitted.

[0115] Next, container 100, which is a foamed sheet molded article, is cut out from foamed sheet 2 by die-cutting machine 224.

[0116] In the foamed sheet of the present embodiment, the polyester resin and the polyetherimide resin are compatible with each other, and the storage modulus determined by solid viscoelasticity measurement is a minimum value (E' A ), it can maintain a moderate degree of flexibility when heated, further improving moldability. The foamed sheet molding of the present embodiment has a minimum storage modulus (E'B ) is 1.0 to 10.0 MPa in the measurement temperature range of 30 to 200°C, so that the heat resistance strength and impact resistance can be further improved. [Example]

[0117] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0118] (Raw materials used) <Polyester resin> PET(A): Polyethylene terephthalate, manufactured by Far Eastern New Century Co., Ltd., product name "CH-611", glass transition temperature (Tg): 78°C, melting point: 251°C, IV value: 1.04, biomass content: 0%. PET (B): Polyethylene terephthalate, manufactured by Far Eastern New Century Co., Ltd., product name "CH-653", glass transition temperature (Tg): 79°C, melting point: 248°C, IV value: 1.01, biomass content: 27-30%. PET(C): Polyethylene terephthalate, manufactured by INDRAMA, product name "RAMAPET N1B", glass transition temperature (Tg): 78°C, melting point: 247°C, IV value: 0.80, biomass content: 30%. PEN(D): Polyethylene naphthalate, manufactured by Teijin Limited, product name "Teonex TN8050SC", glass transition temperature (Tg): 120°C, melting point: 265°C, IV value = 0.51, biomass content: 0%.

[0119] <Polyetherimide resin (PEI)> PEI(E): Polyetherimide, manufactured by SABIC Innovative Plastics, trade name "Ultem1000", glass transition temperature (Tg): 217°C, MFR: 9g / 10min. PEI(F): Polyetherimide, manufactured by SABIC Innovative Plastics, trade name "Ultem1010", glass transition temperature (Tg): 217°C, MFR: 17.8g / 10min.

[0120] <Talc masterbatch> Talc MB: Masterbatch consisting of PET = 72 mass% and talc = 28 mass%.

[0121] <Crosslinking agent> · PMDA: Pyromellitic anhydride.

[0122] (Foam sheet characteristics) <Thickness> The thickness of the foam sheet was measured at nine equally spaced points in the width direction (TD) of the foam sheet, excluding 20 mm strips at both ends, using a dial thickness gauge SM-112 (manufactured by Teclock Corporation), and the arithmetic mean of the measured values ​​was taken as the thickness.

[0123] <Basic weight> Six 10cm x 10cm pieces were cut out from the foam sheet at equal intervals in the width direction (TD direction), excluding 20mm from both ends, and the mass (g) of each piece was measured to the nearest 0.001g. The average mass (g) of each piece was used as the 1m 2 The value converted to the mass per unit area is used as the basis weight (g / m 2 ) was decided.

[0124] <Apparent density> It was calculated from the basis weight and thickness of the foamed sheet using the following formula (s1). Apparent density (g / cm 3 ) = basis weight (g / m 2 ) ÷ thickness (mm) ÷ 1000 (s1)

[0125] <Expansion ratio> The density of the thermoplastic resin was determined from the blending ratio of each example, and the value obtained by dividing the density of the thermoplastic resin by the apparent density of the resulting foamed sheet was used as the expansion ratio. The following values ​​were used for the density of each resin. PET: 1.35g / cm 3 . PEN: 1.33g / cm 3 . PEI: 1.28g / cm 3 .

[0126] <Open cell ratio> Two or more sheet samples measuring 25 mm long x 25 mm wide were cut out from the foam sheet, and the cut samples were stacked together without leaving any gaps to obtain a test piece with a thickness of 25 mm. The outer dimensions of the obtained test piece were measured to 1 / 100 mm using a Mitutoyo Digimatic Caliper caliper, and the apparent volume (V1: cm 3 Next, the volume of the test piece (V2: cm) was measured using a Tokyo Science Co., Ltd. "1000 Type" air comparison hydrometer by the 1-1 / 2-1 atmospheric pressure method. 3 ) was determined. The open cell rate (%) was calculated using the following formula (s2), and the average open cell rate of the five test pieces was calculated. The test pieces were previously conditioned for 24 hours or more in a standard atmosphere of class 2 (temperature 23±2°C, relative humidity 50±5%) according to JIS K7100:1999, and then measured in the same standard atmosphere. The air comparison hydrometer was used with a standard ball (large 28.96 cm 3 , small 8.58cm 3 ) was corrected. Open cell ratio (%) = (V1 - V2) / V1 × 100 (s2) (V1: apparent volume measured using a vernier caliper, V2: volume measured using an air comparison hydrometer)

[0127] (Characteristics of foam sheet and foam sheet molded article (hereinafter simply referred to as "molded article")) <Melting point, crystallization temperature, glass transition temperature> The melting point, crystallization temperature, and glass transition temperature were measured in accordance with the methods described in JIS K7121:1987 and JIS K7121:2012, except that the sampling method and temperature conditions were as follows. A sample cut from the foam sheet or molded article was packed into the bottom of an aluminum measurement container (5.5±0.5 mg) without leaving any gaps, and then the container was covered with an aluminum lid. Differential scanning calorimetry (DSC) was then performed using a Hitachi High-Tech Science DSC7000X, AS-3 differential scanning calorimeter. The sample was heated and cooled under a nitrogen gas flow rate of 20 mL / min, following the steps 1 to 4 below, to obtain a DSC curve. (Step 1) Hold at 30°C for 2 minutes. (Step 2) The temperature is increased from 30°C to 300°C at a rate of 10°C / min (first temperature increase process) and maintained at this temperature for 10 minutes. (Step 3) Quickly remove the sample and allow it to cool in an environment of 25±10°C. (Step 4) The temperature is increased from 30°C to 300°C at a rate of 10°C / min (second temperature increase process). Alumina was used as the reference material. Using the analysis software provided with the instrument, the temperatures at the top of the melting peak and crystallization peak observed during the second heating process were read as the melting point and crystallization temperature, as shown in Figure 11. The glass transition temperature (Tg) was calculated from the DSC curve observed during the second heating process using the analysis software provided with the instrument. This midpoint glass transition temperature was determined according to 9.3(1) of the aforementioned JIS K7121:2012 standard. The glass transition temperature (Tg) was determined as the temperature lower than the crystallization peak observed during the second heating process in a heat flux differential scanning calorimetry chart (DSC curve) at a heating rate of 10°C / min. However, if no crystallization peak was observed during the second heating process, the glass transition temperature in the temperature range (30 to 300°C) during the second heating process was used.

[0128] <Storage modulus and loss tangent> The storage modulus and loss tangent (tanδ) were measured by solid viscoelasticity measurement (DMA measurement). For the solid viscoelasticity measurement, an "EXSTRAR DMS6100" viscoelasticity spectrometer manufactured by SII Nano Technology, Inc. was used. Samples (test pieces) with a length of approximately 40 mm and a width of approximately 10 mm were cut from the foam sheet or molded body. The dimensions of the test pieces were measured using a "DIGIMATIC" CD-15 type manufactured by Mitutoyo Corporation. The conditions for the solid viscoelasticity measurement were as follows: [Measurement conditions] Mode: Tension control mode. Atmosphere: Nitrogen atmosphere. Frequency: 1Hz ·Heating rate: 5℃ / min. ·Measurement temperature: 30℃~300℃. Chuck spacing: 20mm. ·Distortion amplitude: 5μm. ·Minimum tension: 100mN. Tension Gain: 1.5 Initial force amplitude: 100mN.

[0129] The minimum value of the storage modulus (E') in the measurement temperature range of 30 to 200°C A ) was calculated from the curve of change in storage modulus versus temperature using the analysis software provided with the device, as shown in Figure 8. Specifically, for each measurement point of storage modulus, the storage modulus (y-axis) was plotted against the temperature (x-axis), and the minimum value (E') was determined when the slope a of the linear approximation equation (y = ax + b) (where a is the slope of the linear approximation equation and b is the intercept of the linear approximation equation) of the three adjacent measurement points was in the range of a < 0 to a > 0. A ) was judged as "present." In addition, at each measurement point where the slope a was from a<0 to a>0, the smallest value of the storage elastic modulus was taken as the minimum value of the storage elastic modulus (E' A When multiple minimum values ​​are observed in the change curve, the minimum value with the smallest storage modulus among the minimum values ​​is taken as the minimum value (E' A ) was adopted. The minimum storage modulus (E') in the measurement temperature range of 30 to 200°C B ) and loss tangent (tan δ) were determined using the analysis software provided with the device. 8 shows the results of measuring the storage modulus in Example 5 (described later), and Fig. 9 shows the results of measuring the storage modulus in Comparative Example 2 (described later). Fig. 10 shows the results of measuring the loss tangent (tan δ) in Example 5 (described later).

[0130] <Endothermic amount (a), exothermic amount (b), degree of crystallinity> The endothermic amount (a) (heat of fusion) and the exothermic amount (b) (heat of crystallization) were measured by differential scanning calorimetry (DSC) according to the method described in JIS K7122:1987 and JIS K7122:2012. The sampling method and temperature conditions were as follows: A sample cut from the foam sheet or molded body was packed into the bottom of an aluminum measurement container (5.5±0.5 mg) without leaving any gaps, and then the container was covered with an aluminum lid. Differential scanning calorimetry (DSC) was then performed using a Hitachi High-Tech Science DSC7000X, AS-3 differential scanning calorimeter. The sample was heated and cooled under a nitrogen gas flow rate of 20 mL / min according to the following steps 1 and 2 to obtain a DSC curve. (Step 1) Hold at 30°C for 2 minutes. (Step 2) Heat from 30°C to 300°C at a heating rate of 10°C / min (first heating process). Alumina was used as the reference material. The endothermic amount (a) and the calorific value (b) were calculated using the analysis software provided with the instrument. Specifically, as shown in Figure 11, the endothermic amount (a) was calculated from the area enclosed by the line connecting the point where the DSC curve departs from the low-temperature baseline and the point where the DSC curve returns to the high-temperature baseline, as well as the area enclosed by the line connecting the point where the DSC curve departs from the low-temperature baseline and the point where the DSC curve returns to the high-temperature baseline. The calorific value (b) was calculated from the area enclosed by the line connecting the point where the DSC curve departs from the low-temperature baseline and the point where the DSC curve returns to the high-temperature baseline, as well as the area enclosed by the line connecting the point where the DSC curve departs from the low-temperature baseline and the point where the DSC curve returns to the high-temperature baseline. The crystallinity was calculated using the endothermic amount (a) and the exothermic amount (b) according to the following formula (s3). Crystallinity (%) = {(absolute value of endothermic heat (a) (J / g) - absolute value of exothermic heat (b) (J / g)) ÷ heat of fusion of perfect crystals (J / g)} × 100 (s3) The heat of fusion of a perfect crystal represents the amount of heat when 100% crystallization occurs. Note that the heat of fusion of a perfect crystal in the above formula (s3) was 140.1 J / g, which is the heat of fusion of a perfect crystal of PET.

[0131] <Number average molecular weight (Mn), mass average molecular weight (Mw), and Z average molecular weight (Mz)> The number average molecular weight (Mn), weight average molecular weight (Mw), and Z average molecular weight (Mz) were measured by gel permeation chromatography (GPC). A 5 mg sample was taken from the foam sheet or molded article, and 0.5 mL of hexafluoroisopropanol (HFIP) and 0.5 mL of chloroform were added in that order. The mixture was gently shaken manually. The mixture was left for 6±1.0 hours. After confirming complete dissolution, the sample was diluted with chloroform to a total volume of 10 mL and gently shaken manually to mix. The mixture was then filtered through a non-aqueous 0.45 μm chromatodisc (GL Sciences Inc.) or a non-aqueous 0.45 μm syringe filter (Shimadzu GLC Corporation) to prepare a measurement sample. The measurement sample was measured using a chromatograph under the following measurement conditions. The number-average molecular weight (Mn), mass-average molecular weight (Mw), and Z-average molecular weight (Mz) of the sample were determined from a previously prepared standard polystyrene calibration curve.

[0132] [Measuring equipment] Measurement equipment: Tosoh Corporation's "HLC-8320GPC EcoSEC" gel permeation chromatograph (with built-in RI and UV detectors). [GPC measurement conditions] ·column <Sample side> Guard column = 1 TSK guard column HXL-H (6.0 mm x 4.0 cm) manufactured by Tosoh Corporation. Measurement column: TSKgel GMHXL (7.8 mm I.D. x 30 cm) x 2 columns, manufactured by Tosoh Corporation, in series. <Reference side> Two resistance tubes (inner diameter 0.1 mm x 2 m) in series. Column temperature = 40°C. Mobile phase = chloroform. <Mobile phase flow rate> Sample side pump = 1.0 mL / min. Reference pump = 0.5 mL / min. Detector = UV detector (254 nm). Injection volume = 15 μL. Measurement time = 25 min. Sampling pitch = 500 ms.

[0133] [Standard polystyrene sample for calibration curve] The standard polystyrene samples used for the calibration curve were "STANDARD SM-105" and "STANDARD SH-75" manufactured by Showa Denko K.K., with mass average molecular weights (Mw) of 5,620,000, 3,120,000, 1,250,000, 442,000, 151,000, 53,500, 17,000, 7,660, 2,900, and 1,320. The above calibration curve standard polystyrene was divided into groups A (5,620,000, 1,250,000, 151,000, 17,000, 2,900) and B (3,120,000, 442,000, 53,500, 7,660, 1,320). A was weighed (2 mg, 3 mg, 4 mg, 4 mg, 4 mg) and dissolved in 30 mL of chloroform. B was weighed (3 mg, 4 mg, 4 mg, 4 mg, 4 mg) and dissolved in 30 mL of chloroform. A calibration curve (cubic equation) was prepared by injecting 50 μL of each of the prepared solutions A and B and plotting the retention times obtained after measurement. The number-average molecular weight (Mn), mass-average molecular weight (Mw), and Z-average molecular weight (Mz) were calculated using the calibration curve.

[0134] (Performance evaluation method for foam sheets) <Dimensional stability of foamed sheets during heating (heat deformation test)> Five flat square test pieces, each about 10 cm on a side, were cut out from the foam sheet so that each side was parallel to the extrusion direction (MD) or width direction (TD) of the foam sheet. Next, two straight lines connecting the centers of the opposing sides of each foamed sheet were drawn in a cross shape. The lengths of the lines in each direction before heating were designated MD1 and TD1. Each foamed sheet was then placed on a platform in an oven set to a predetermined temperature without humidity control, heated for 150 seconds, removed from the oven, and cooled at room temperature for 30 minutes. The lengths of the straight lines drawn in each direction before heating were measured, and the arithmetic mean of the measured lengths for each foamed sheet was designated the length after heating. From the obtained lengths after heating MD2 and TD2 and the lengths before heating MD1 and TD1, the ratio of the length before heating (MD1) to the length after heating (MD2) in the extrusion direction (MD ratio = MD2 / MD1) and the ratio of the length before heating (TD1) to the length after heating (TD2) in the width direction (TD ratio = TD2 / TD1) were calculated. The dimensional stability of the foamed sheet in each example under heat was evaluated based on the following evaluation criteria.

[0135] <Evaluation Criteria> ◎: At a setting of 140℃, the smaller of the MD ratio and TD ratio is 0.97 or more. Good: The smaller of the MD ratio and TD ratio is less than 0.97 when set at 140°C, and the smaller of the MD ratio and TD ratio is 0.97 or more when set at 120°C. △: The smaller of the MD ratio and TD ratio at a temperature setting of 140°C is less than 0.97, and the smaller of the MD ratio and TD ratio at a temperature setting of 120°C is 0.95 or more and less than 0.97. ×: The smaller of the MD ratio and the TD ratio at a temperature set to 140°C is less than 0.97, and the smaller of the MD ratio and the TD ratio at a temperature set to 120°C is less than 0.95.

[0136] <Heat resistance strength of foam sheet (heat tensile test)> The tensile modulus in the heat tensile test was measured in accordance with JIS K7127:1999 using a Shimadzu Corporation "Autograph AG-Xplus 100kN" universal testing machine and a Shimadzu Corporation "TRAPEZIUM X" universal testing machine data processing system. The test specimens were dumbbell-shaped type 5, cut so that their length was in the extrusion direction (MD). The test speed was 200mm / min, and the grip spacing was 80mm. The test specimens were conditioned for at least 24 hours in a standard atmosphere of JIS K7100:1999, "23 / 50", Class 2, before use in the test. Measurements were carried out under standard atmosphere (23°C) and at 80°C. At 80°C, the test specimen was clamped in a jig installed in a thermostatic chamber attached to a Shimadzu Corporation "TCR2A Model" and held for 1 minute before measurement. Five test specimens were measured at each of the above ambient temperatures, and the arithmetic mean of the tensile modulus values ​​for each test specimen was taken as the tensile modulus value. The tensile modulus was calculated by setting the region where the slope was maximum within the tensile proportional limit and processing the data from the universal testing machine. The retention rate was calculated by the following formula (s4) using the tensile modulus at 80°C (E80) and the tensile modulus at standard atmosphere (23°C) (E23). The heat resistance strength of each foamed sheet was evaluated based on the following evaluation criteria. Retention rate (%)=(E80) / (E23)×100...(s4)

[0137] <Evaluation Criteria> ◎: Retention rate is 50% or more. Good: Retention rate is between 40% and 50%. △: Retention rate is 25% or more and less than 40%. ×: The retention rate is less than 25%.

[0138] <Impact resistance of foam sheets (drop weight impact test)> The total absorbed energy in the drop weight impact test was measured in accordance with ASTM D3763-15. The total absorbed energy was measured using a drop weight impact tester "CEAST9350" manufactured by CEAST and measurement software "CEAST VIEW." The test specimen size was 100 mm long x 100 mm wide. The number of test specimens was a minimum of five, and the basis weight of each test specimen was within ±5% of the basis weight of the foam sheet listed in the tables for the Examples and Comparative Examples. The test conditions were as follows:

[0139] [Test conditions] Test speed: 1.76m / s Drop weight: 1.9265kg. · Specimen support span: φ76mm. -Tap used: 4.5kN instrumented tap (tip φ12.7mm hemispherical). The test specimens were conditioned for 16 hours in an environment according to Procedure A of ASTM D618-13 (23±2°C, 50±10% relative humidity) before use. The total absorbed energy of each test specimen was calculated by automatically integrating the graph obtained by the measurement using the measurement software. The average value of the total absorbed energy of each test specimen at the test temperature (23°C) was taken as the total absorbed energy of the foam sheet. The impact resistance of each foam sheet was evaluated based on the following evaluation criteria.

[0140] <Evaluation Criteria> ◎: Total absorbed energy is 0.40 J or more. 〇: Total absorbed energy is 0.25J or more but less than 0.40J. △: Total absorbed energy is 0.15J or more and less than 0.25J. ×: Total absorbed energy is less than 0.15 J.

[0141] <Moldability of foam sheets> A flat rectangular test piece measuring 700 mm long x 1050 mm wide was cut out from the foam sheet. A single-shot molding machine (manufactured by Tosei Sangyo Co., Ltd., product name "Unic Automatic Molding Machine FM-3A") was prepared, and the average temperature of the upper heater of this single-shot molding machine was set to 304°C, the average temperature of the lower heater to 267°C, the upper ambient temperature to 206°C, and the lower ambient temperature to 206°C. Next, the test piece was introduced into the single-shot molding machine, and the surface temperature of the foam sheet (T S ) for a predetermined time until the temperature reached the range shown in Tables 7 to 10. Then, molding was carried out using a mold (mold surface temperature 50°C) in which 22 truncated cones of 10 mm diameter (top) x 35 mm diameter (bottom) and different heights were arranged. The heights and drawing ratios of the 22 truncated cones were as shown in Table 14. The molded product was visually observed for the drawing ratio at which the shape was formed according to the mold without any tears or holes, and the moldability of the foamed sheet of each example was evaluated based on the following evaluation criteria.

[0142] <Evaluation Criteria> ◎: The drawing ratio is 1.6 or more. ○: The drawing ratio is 1.3 or more and less than 1.6. △: The drawing ratio is 1.0 or more and less than 1.3. ×: The drawing ratio is less than 1.0 or molding is not possible. Here, "unmoldable" means that in the case of the truncated cone No. 1 in Table 14, the shape is significantly different from the shape of the mold, or tears or holes are found in the molded product.

[0143] <<Overall evaluation of foam sheets>> ◎: All items were rated as "◎" or "〇". 〇: There were no "×" marks in the evaluation of any item, and there was one "△" mark in the evaluation of any item. △: There were no "x" marks in the evaluation of any item, and two or more "△" marks in the evaluation of any item. ×: The evaluation of any item was "×".

[0144] (Method for evaluating the performance of molded products) <Impact resistance of molded products> Five molded articles (containers) of each example were prepared, filled with 250 mL of water, and left to stand at -25°C for 24 hours to obtain containerized frozen products. In a -25°C environment, the containers were oriented with the lengthwise direction vertical and the widthwise direction horizontal, and each containerized frozen product was dropped from a height of 80 cm onto a horizontal steel plate. After that, all of the dropped containerized frozen products were visually observed, and the impact resistance of each molded article was evaluated for damage (cracks or penetration of the container) based on the following evaluation criteria.

[0145] <Evaluation Criteria> ◎: Number of missing containers is 0 to 2. O: The number of missing containers is 3. △: Number of missing containers: 4 ×: 5 containers were missing.

[0146] <Heat resistance strength of molded body> 100 g of salad oil was placed in each molded body and heated for 60 seconds in a commercial microwave oven (microwave oven: Panasonic Corporation, Model NE1901S) at an output of 1600 W. Immediately after that, the molded body with the salad oil inside was lifted up, and the degree of deformation of the molded body was visually confirmed. The heat resistance strength of each molded body was evaluated based on the following evaluation criteria.

[0147] <Evaluation Criteria> ◎: No deformation and can be lifted with one hand. 〇: It deforms a little, but can be lifted with one hand. △: It deforms significantly, but can be lifted with one hand. ×: The deformation is so great that it cannot be lifted with one hand.

[0148] <Overall evaluation of molded body> ◎: All items were rated as "◎". Good: All items were rated as "◎" or "Good", with at least one being "Good". △: No "x" was given in the evaluation of any item, and at least one "△" was given in the evaluation of any item. ×: The evaluation of any item was "×".

[0149] Example 1 According to the formulation in Table 2, a polyester resin, a polyetherimide resin, a talc masterbatch, and a crosslinking agent were mixed in a mixer to prepare a blend. A circular die with a 93 mm diameter annular slit and a 0.36 mm slit width was attached to the tip of a single-screw extruder (diameter 65 mm, L / D = 34). A cylindrical cooling mandrel (diameter 206 mm, length 310 mm) was placed ahead of the circular die in the extrusion direction. Cooling water was circulated through the cooling mandrel. The extruder was set to a predetermined temperature, and the compound was kneaded in the extruder to form a molten mixture. A foaming agent (isobutane: normal butane = 35:65 (mass ratio)) was injected midway through the extruder barrel and added to the molten resin, which was then further kneaded to form a thermoplastic resin composition. The resin temperature during extrusion was set to 300°C, and the molten thermoplastic resin composition was extruded through the die slit of the circular die at a discharge rate of 30 kg / h to form a cylindrical foam. The cylindrical foam was expanded in diameter using a cooling mandrel and taken up by a take-up machine located further downstream from the cooling mandrel. The foam was cooled by placing the outer surface of the cooling mandrel along the inner surface of the foam, and the cylindrical foam was cut along the extrusion direction downstream of the cooling mandrel. The cylindrical foam was then cut into a flat, strip-shaped foam sheet and wound into a roll using a take-up machine. The properties of the resulting foam sheet are shown in Table 2, and the performance evaluation of the foam sheet is shown in Table 7.

[0150] (Examples 2 to 14, 17 to 19, Comparative Examples 1 to 4) Foamed sheets were produced in the same manner as in Example 1, except that the resin temperature during extrusion and the take-up speed of the take-up machine were adjusted according to the formulations in Tables 2 to 6. The properties of the obtained foamed sheets are shown in Tables 2 to 6, and the performance evaluations of the foamed sheets are shown in Tables 7 to 9.

[0151] Example 15 A foamed sheet was prepared in the same manner as in Example 1 according to the formulation in Table 4. The prepared foamed sheet was cut into a flat square with sides of 250 mm. The cut foamed sheet was sandwiched between a pair of hot plates heated to 180°C, and maintained at this temperature for 5 seconds until the surface temperature of the foamed sheet reached 180°C. The properties of the obtained foamed sheet are shown in Table 4, and the performance evaluation of the foamed sheet is shown in Table 8.

[0152] Example 16 A foamed sheet was prepared in the same manner as in Example 1 according to the formulation in Table 5. The prepared foamed sheet was cut into a flat square with one side of 250 mm. The cut foamed sheet was sandwiched between a pair of hot plates heated to 180°C, and maintained at this temperature for 10 seconds until the surface temperature of the foamed sheet reached 180°C. The properties of the obtained foamed sheet are shown in Table 5, and the performance evaluation of the foamed sheet is shown in Table 8.

[0153] (Comparative Example 5) A foamed sheet was prepared in the same manner as in Example 1 according to the formulation in Table 6. The prepared foamed sheet was cut into a flat square with one side of 250 mm. The cut foamed sheet was sandwiched between a pair of hot plates heated to 180°C, and maintained at this state for 10 minutes until the surface temperature of the foamed sheet reached 180°C. The properties of the obtained foamed sheet are shown in Table 6, and the performance evaluation of the foamed sheet is shown in Table 9.

[0154] Examples 20 to 27 The foamed sheets obtained in Examples 1 and 5 were used to measure the surface temperature (T S ) was adjusted to the temperatures shown in Table 10. Table 10 shows the evaluation of the moldability of the foamed sheet.

[0155] [Table 2]

[0156] [Table 3]

[0157] [Table 4]

[0158] [Table 5]

[0159] [Table 6]

[0160] [Table 7]

[0161] [Table 8]

[0162] [Table 9]

[0163] [Table 10]

[0164] The overall evaluation of Examples 1 to 19 to which the present invention was applied was "△" to "◎", and the moldability was particularly excellent. In contrast, in Comparative Example 1, which does not contain a polyetherimide resin, the storage modulus was at a minimum (E' A The overall evaluation of Comparative Examples 2 to 5, which did not have the above-mentioned additives, was "×". Although the moldability of Comparative Example 1 was evaluated as "◎", the dimensional stability upon heating and heat resistance strength, which are the basic functions of a foamed sheet, were evaluated as "×", and therefore it was determined that the problem of the present invention was not solved.

[0165] The moldability of Examples 20 to 27, to which the present invention was applied, was evaluated as "△" to "◯." S) and confirmed that formability could be further improved by adjusting the

[0166] Example 28 The foamed sheet obtained in Example 1 before heat setting was prepared and cut into a flat square with a side of 250 mm. The foamed sheet was set in a frame so that the extrusion (MD) direction was the longitudinal direction of the container, and the foamed sheet was preheated in a heater tank at 320°C for 10 seconds to obtain a surface temperature (T S ) was heated to 130°C. Then, a tray-shaped molded body (210 mm length × 180 mm width × 30 mm height) with an opening at the top was obtained by the match mold molding method. The time required to obtain the molded body (molding cycle time) was 23 seconds. The properties and performance evaluation of the obtained molded body are shown in Table 11.

[0167] (Examples 29 to 38, Comparative Examples 6 to 7) Molded articles were obtained in the same manner as in Example 28, except that the foamed sheets shown in Tables 2 to 6 were used and the molding conditions were changed to those shown in Tables 11 to 13. The properties and performance evaluations of the obtained molded articles are shown in Tables 11 to 13.

[0168] [Table 11]

[0169] [Table 12]

[0170] [Table 13]

[0171] [Table 14]

[0172] The overall evaluation of Examples 28 to 38 to which the present invention was applied was "Fair" to "Excellent." In contrast, the foamed sheet of Comparative Example 6, which was molded using the foamed sheet of Comparative Example 1 that did not contain a polyetherimide resin, was evaluated as "X" overall. B ) was outside the scope of the present invention, the overall evaluation of Comparative Example 7 was "×". Note that Comparative Example 6 was evaluated as "◎" in impact resistance, but was evaluated as "×" in heat resistance strength, which is a basic function of a thermoplastic resin foam sheet molding, and therefore it was determined that the problem of the present invention was not solved.

[0173] From the above results, it was confirmed that the application of the present invention can improve the moldability of a thermoplastic resin foam sheet. It was also confirmed that application of the present invention can improve the impact resistance of a thermoplastic resin foam sheet molding. [Industrial Applicability]

[0174] The thermoplastic resin foam sheet and the thermoplastic resin foam sheet molded article of the present invention have excellent moldability, heat resistance, and impact resistance, and are therefore suitable for use as food containers, particularly deep-draw containers and food containers having complex uneven shapes. They can also be used for applications other than food containers, such as cushioning materials, packaging materials, structural members, and heat insulating materials used in industrial components for electrical appliances and automobiles. [Explanation of symbols]

[0175] 2. Foam sheets 22 Foam layer 100 Container (molded body)

Claims

1. a sheet-like foam layer containing a thermoplastic resin; the thermoplastic resin includes a polyester-based resin and a polyetherimide-based resin, The storage modulus determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz is a minimum value (E' Ａ ). A thermoplastic resin foam sheet having the following properties.

2. The minimum value (E' Ａ 2. The thermoplastic resin foam sheet according to claim 1, wherein the compressive strength (S) of the thermoplastic resin foam sheet is 1.0 to 10.0 MPa.

3. The storage modulus (E') at 30°C is determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz. ３０ ) and the minimum value (E' Ａ ) and the ratio (E' ３０ / E' Ａ 3. The thermoplastic resin foam sheet according to claim 1, wherein the molecular weight of the thermoplastic resin foam is 40 to 400.

4. The Z-average molecular weight (M Ｚ 4. The thermoplastic resin foam sheet according to claim 1, wherein the molecular weight of the thermoplastic resin foam is 300,000 to 700,000.

5. The temperature (t') at which the loss tangent (tan δ) is maximized by measuring the solid viscoelasticity at a heating rate of 5°C / min and a frequency of 1 Hz. ＭＡＸ 5. The thermoplastic resin foam sheet according to claim 1, wherein the viscosity of the thermoplastic resin foam is 80 to 130°C at a measurement temperature range of 30 to 200°C.

6. the content ratio of the polyester resin to the total mass of the thermoplastic resin is 60 to 95 mass %, The thermoplastic resin foam sheet according to any one of claims 1 to 5, wherein a content ratio of the polyetherimide-based resin to a total mass of the thermoplastic resin is 5 to 40 mass%.

7. The thermoplastic resin foam sheet according to any one of claims 1 to 6, wherein an absolute value of the difference between the endotherm and the heat release determined by heat flux differential scanning calorimetry at a heating rate of 10°C / min is 3 to 21 J / g.

8. a sheet-like foam layer containing a thermoplastic resin; the thermoplastic resin includes a polyester-based resin and a polyetherimide-based resin, The minimum value of the storage modulus (E') determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz Ｂ ) is 1.0 to 10.0 MPa at a measurement temperature range of 30 to 200°C.

9. The storage modulus (E') at 30°C is determined by solid viscoelasticity measurement at a heating rate of 5°C / min and a frequency of 1 Hz. ３０ ) and the minimum value (E' Ｂ ) and the ratio (E' ３０ / E' Ｂ 9. The thermoplastic resin foam sheet molded article according to claim 8, wherein the molecular weight of the thermoplastic resin foam sheet is 40 to 200.

10. The Z-average molecular weight (M Ｚ 10. The thermoplastic resin foam sheet molded article according to claim 8, wherein the molecular weight of the thermoplastic resin foam sheet is 300,000 to 700,000.

11. The temperature (t') at which the loss tangent (tan δ) is maximized by measuring the solid viscoelasticity at a heating rate of 5°C / min and a frequency of 1 Hz. ＭＡＸ 11. The thermoplastic resin foam sheet molded product according to claim 8, wherein the viscosity of the thermoplastic resin foam sheet is 80 to 130°C at a measurement temperature range of 30 to 200°C.

12. the content ratio of the polyester resin to the total mass of the thermoplastic resin is 60 to 95 mass %, The thermoplastic resin foamed sheet molded product according to any one of claims 8 to 11, wherein a content ratio of the polyetherimide resin to a total mass of the thermoplastic resin is 5 to 40 mass%.

13. The thermoplastic resin foam sheet molded product according to any one of claims 8 to 12, wherein the absolute value of the difference between the endotherm and the heat release determined by heat flux differential scanning calorimetry at a heating rate of 10°C / min is 7 to 28 J / g.

14. 14. The thermoplastic resin foam sheet molding according to claim 8, comprising a bottomed cylindrical container body including a bottom wall portion that is circular in plan view and a side wall portion that stands upright from a peripheral edge of the bottom wall portion, wherein the container body tapers from an opening toward the bottom wall portion, and a drawing ratio expressed as (height of the side wall portion) / (opening diameter of the opening portion) is 0.5 to 2.

0.

15. a heating step of heating the thermoplastic resin foam sheet according to any one of claims 1 to 7; a molding step of sandwiching the thermoplastic resin foam sheet between a female mold and a male mold, The molding step is a method for producing a molded thermoplastic resin foam sheet, in which the thermoplastic resin foam sheet satisfying the following formula (I) is sandwiched between the female mold and the male mold to mold it: (T Ａ -30)℃≦(T Ｓ )℃≦(T Ａ +30)℃ ・・・(I) [In the formula (I), T Ｓ represents the surface temperature of the thermoplastic resin foam sheet, and T Ａ is the minimum value (E' Ａ ) represents the temperature at which

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