JPS5951819A - Container for electronic range and oven range - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The invention relates to containers for containers.

Recently, in the food industry, with the diversification of eating habits, home-cooked foods using Ryuko resin, Open, etc. have begun to be widely available. - Conventionally, there are many boil-in-bags on the market that re-cook foods that have been processed twice, such as curry, stew, and hamburgers, as packaging materials for cooked foods. With the spread of cooking equipment, packaging materials with excellent mechanical strength, heat resistance, and appearance are required for food packaging. .

However, although commonly used polyvinyl chloride, polystyrene, polyolefin, etc. have excellent mechanical strength and durability, they do not have the heat resistance to withstand food and cooking. On the other hand, tray containers made of paper board laminated with heat-resistant polyester and decorated with patterns have recently been seen on the shelves.

In this case, the heat resistance is much improved compared to the conventional packaging materials as described above, and it is a useful packaging material for cooked foods. However, among cooked foods, such as gratin, hamburger, bakery bread, etc., which require the first burnt point, it is difficult to use IJZ for buried foods.
There are high expectations for packaging materials that can be processed using maven grains.

On the other hand, it is known to manufacture containers from resin sheets by thermoforming methods such as vacuum forming methods and pressure forming methods, and four volumes have been produced in the industry.

In such thermoforming, the sheet is shaped by reduced pressure or air pressure, so the sheet is required to have a higher formability. Therefore, the thickness of the container is t=l: 'pr11, and the container of the molded product is not designed to have mechanical strength and heat resistance.

For example, a sheet of non-oriented, non-polymerized polyethylene prephthalate has thermoformability and has the advantage of being able to be molded into containers with excellent mechanical properties, transparency, and the like. However, the heat resistance of this young product is limited to that used for cooked foods, and is approximately 8.
There is a drawback that there is almost no shape retention in an atmosphere of 0° C. or higher.

A container for cooking and packaging as described above that fully satisfies the above-mentioned characteristics is required.

The present inventors have eliminated those drawbacks, and have improved mechanical strength and
As a result of extensive research into producing containers with improved heat resistance, appearance characteristics, moldability, etc., containers molded from polyetherimide-based sheets have been developed that can be used in microwave ovens and/or open microwave ovens. The present invention was achieved by obtaining knowledge that satisfies the characteristics.

That is, the present invention is a container formed from a sheet containing polyetherimide as a main component. There is no problem even if the sheet is a film. This sheet may be made of polymer, paper impregnated with a dope made by dissolving a polymer in a solvent, or a laminate of a polymer sheet and paper. The sheet is formed into a tray or three-dimensional container by shallow drawing or deep drawing using a vacuum forming method, a pressure forming machine, or a universal forming machine that uses a combination of vacuum and pressure. Impregnated paper and laminated paper do not have the deep drawability of plastic sheets, so in this case, they can be folded like a paper box to make a container, or if the tray has a shallow bottom, the corners can be geared. Containers can be molded.

In molding a polymer sheet, when the sheet is made of polyetherimide alone, it has excellent heat resistance. In addition, sheet d containing other polymers as subcomponents has excellent deep drawability. Considering the compatibility, heat resistance, and moldability of polymers, the most important subcomponent for women in particular is polycarbonate, which is particularly popular among polynisdels such as polyethylene terephthalate 1 and polybutylene terephthalate, and their polymers. - or a copolymer. If the subcomponent content is less than 40%, the container will be blown away, will have excellent heat resistance when used in a microwave oven or in a microwave oven, and will have little deformation of the container when used in a microwave oven. Further, a sheet with substantially no texture has excellent formability, but in order to improve strength, it is preferable to use a sheet that has been stretched at a stretching ratio of 3 times or less. A sheet stretched to a stretching ratio of 3 or more times -2 has poor deep drawability and is prone to breakage during forming.

Fi'i layering of paper onto a polymer sheet can be accomplished by conventional extrusion coating techniques, or even by laminating the paper to the sheet using an adhesive. This polymer sheet is easily dissolved and swollen by chloroform, trichlene, and other non-rogenated hydrocarbons, and ketones such as methyl ethyl lactone, so wet the surface of the polymer sheet with these organic solvents to partially dissolve and swell. There is no problem even if the paper is laminated.

To obtain impregnated paper, paper may be dipped or coated in a dope prepared by dissolving a polymer in an organic solvent such as those mentioned above, and then dried. In this case, the polymer concentration of the dope is in the range of 1 to 80% by weight, more preferably 5 to 30% by weight. If the concentration is low, the thermal properties of the surface of the container will be poor, and if the concentration is high, the moisture content will be insufficient, and even in the case of coating, it will be difficult to form a film at high speed.

The polyetherimide used in the present invention has the following formula: [wherein a represents an integer greater than 1, such as 10 to 10.000 or more, and 1, -〇-z-o
- is at the 3-4 or 4-position and the 3'-straddling 4'-position, and 2 is (]) a group represented by the following formula: and (2) the following formula; 0 0 (wherein, X is Formula: cyl12y, -Cnie, -
5-1-0-0 and -8- are divalent bases or atoms selected from 11", q is 0 or l, and y ff 1~
represents a group selected from the group consisting of divalent organic groups represented by
The divalent bond of is on the phthalic anhydride end group, for example 3.
3'-, 3,4'-14,3'-, or 4.4'-(
b) an alkylene group and a cycloalkylene group having 2 to 20 carbon atoms, a polydiorganosiloxane terminal-terminated with an alkylene group having 2 to 8 carbon atoms; and (C) an atom or group selected from the formula: -CXII2X-; , or an integer from 1 to 5).

The polyneedlelimide of the formula I is composed of an aromatic acid bis(ether anhydride) of the formula ■; having the meaning given above) with a diamino compound.

Generally, useful polyneedlelimides of formula l (hereinafter PEI
) has an intrinsic viscosity of greater than 0.2 dt/f when measured in m-cresol at 25°C.
η], preferably 1.0.35 to 0.6(], dimension 0.
It has an intrinsic viscosity of 7 dl/y or greater than 11 dl/y.

Many of these polyetherimides have a glass transition point of 19
It has excellent heat resistance at temperatures below 0°C.

This polyetherimide can be used as a homopolymer, or as a copolymer or a polymer alloy with other polymers as long as the strength and heat resistance are not reduced. Polymer alloys include polyester, polyamide, polyolefin, polyacetal, polyvinyl chloride, fluororesin, polystyrene, polyamideimide, polysulfone, polyphenylene sulfide, polyphenylene ether, polyether sulfone, polyarylate, polyallyl sulfone, polyphenylene oxide, polysulfone, −
It is made from resin such as bonate and polyetherimide.

Antistatic agents, solvents, colorants, stabilizers, weathering agents, mold release agents, fillers, etc. may be added to these homopolymers, copolymers, and polymer alloys. There is no problem even if the surface of the film is subjected to antistatic processing, vapor deposition processing, antifogging processing, coating processing, spray processing, etc.

The film may also be dyed. In addition, when used, it can be used as a single film, a composite or a laminate by combining it with other plastic films or other old materials. .

Film resistance is determined by melt extrusion method, chloroform, trichlene,
Polymers can be dissolved in organic solvents such as aromatic hydrocarbons such as trichloroethane and methyl ethyl ketone, halogenated hydrocarbons, aliphatic hydrocarbons, Nisdels, ketones, etc., with no problem whether the solvent is used alone or as a mixed solvent. γ
It can also be carried out using the solution key Y strike method. The cylindrical material used in the process is usually transparent, but a roughened sheet can be obtained by using a cooling drano used in the bath melt extrusion method or a gearing drum or belt in the solution casting method.

In addition, the surface of the yN bright sheet can be roughened by embossing, lint matting, or mechanical etching.

The roughened sheet has good release properties from the mold during deep drawing, and even when printing on a rough surface, the ink adheres well and is highly suitable for printing.

The thickness of the sheet is usually 0.05 to 1, preferably 0.2
~0.7-.

The sheet thus obtained is further thermoformed into a container of a desired shape.

The thermoforming temperature of polyetherimide as a main component is in the range of room temperature to 330°C, preferably 80°C to 270°C. The heating time is preferably in the range of 1 to iso seconds. Vacuum forming or pressure forming can be performed by a normal method. Fix the heat-softened sheet to the mold and vacuum size or 1 to 15 y/
The sheet is brought into close contact with the mold using CrI pressurized air to form a molded product.

Polymer impregnated paper, coated paper or laminated paper
These are punched out into the shape of a three-dimensional container, and then folded to make boxes and cups. Each surface may be joined by folding, thermal bonding, or adhesive. Moreover, if it is shallowly drawn in the shape of a tray, it can be processed by vacuum forming or pressure forming.

The container of the present invention can be used not only for conventional purposes but also for gratin,
Suitable for use in a microwave oven or open range as a cooking container for cooked foods such as cream stew and hamburgers. Next, methods for measuring physical properties will be described.

1) Glass transition point: Endothermic peak of glass transition measured in accordance with ASTM I) 3418 using a differential scanning calorimeter manufactured by Perkin Elma, Model DSC-2, on a sample of 10 m9, at a column temperature rate of 0°C/min. Determined from temperature.

2) Jv thickness of sheet: Measured using a dial gauge type minute thickness measuring device manufactured by Toyo Seiso Seisakusho with a minimum scale of 11tht.

Hereinafter, the present invention will be described in more detail based on Examples.

Example 1 Polyetherimide (ULTEM 1000!, the glass transition point of this polymer is 216°C) manufactured by General Electric Company, USA and polycarbonate manufactured by Teijin Kasei (trademark Tijin Panlite C-1400) and glass of this polymer. (transition point is 150°C) were blended in various proportions and then vacuum dried at 150°C for 5 hours. The obtained mixture was extruded using an extruder with a screw diameter of 40TM3 at a temperature of 300°C to 380°C and a width of 25Crn.
It was melt-extruded from an r die and cooled and solidified using a cooling roll at m[120 to 150°C. The resulting sheet has a thickness of approximately 30
It was a substantially unoriented, amorphous sheet with a diameter of 0 μm. This sheet was preheated to 180°C for 10 seconds using a female straight vacuum forming machine 'tfφ, and then formed to a length of 13 tM.

A tray with a width of 18 crn and a depth of 2 m was molded. Place the macaroni gratin on this tray and heat it in a household tardar gas oven at 230℃ for 20 minutes to check the shape stability of the tray. nbeta. The heat-resistant tray of the tray molded from a sheet containing a large amount of polyetherimide was deformed. The results are shown in Table 1. Symbol ◎ in Table 1: The shape of the tray did not change at all.

The image of the shape of the 0-nidrei is minute and there is no problem in using it.

△: The shape of the tray was planned.

×The shape of Nidorei changes greatly and does not change its original shape.

Example 2゜Using the polyetherimide of Example 1, this resin 5
0011'i Chloroform 1.51
．． The dope was dissolved in a mixed solvent of 21 and carton paper was immersed in this dope to obtain impregnated paper. Temperature after this g'; -1,50℃
It was dried. Vertical 12 tyn14 near from this impregnated paper
A paper box was made by cutting out the developed shape of a box with a size of 16 m and 4 crn. Shrimp gratin cooked in vermilion was put in the mixture, frozen in a freezer, and after a period of time, the mixture was cooked in the same manner as in Example 1 using the gas oven at temperature 2]0'C for 20 minutes. Cooking was completed without any deformation of the paper box.

Example 3 Using the polyneedle imide of Example 1 1-1 Intrinsic viscosity 0
6s polyethylene prephthalate/isophthalate copolymer (ratio of terephthalate and isophthalate is 9
: 1) were mixed at a ratio of 2.
It was vacuum dried for 4 hours. The resulting mixture was melt-extruded in the same manner as in Example 1 to obtain an unstretched sheet with a thickness of 25011 m. This sheet was stretched in the longitudinal direction using a roll stretching machine at a temperature of 90°C to a magnification of 1.5 times, and using this stretched sheet, a tray of the same shape as in Example 1 was formed using a vacuum forming machine at a temperature of 120°C. It was preheated for 5 seconds and then molded. Place 17 karoni kratan on this tray in the same manner as in Example 1, and cook in a gas oven at 18' and 230°C for 20 minutes (again.

R. The ease of removing the tray from the mold in the nitrogen molding machine, that is, the shapeability of the tray, and the morphology of the tray when cooking in a gas oven were studied. The sheet with a high content of polyetherimide had good moldability and good shape stability. The results are shown in Table 2.

Table 2 Mold release symbol (]): It could be easily removed from the mold.

△: It was possible to remove the mold by cooling it down a little.

×: It is difficult to take out the tray and the molded product is deformed.

Shape stability symbol: Same as Example 1.

Example 4 The polyneedle imide of Example 1 and a mixture of this polyneedle imide and polyethylene terephthalate with an intrinsic viscosity of 90.72 at a mixing ratio of 4:1 were dried at 150°C, and then
Melt extrusion was performed in the same manner as in Example 1 to a thickness of 0.3 tym.
Extrusion coated onto carton paper. Co) 11i
The thickness of A was 140 μm. Both of these polymer coated papers are 12 cm long and 12 cm wide.

A paper box was made by cutting out the entire development of a box with a height of 3 tM so that the coat was on the outside. After filling this box with curry and freezing it in the freezer for 2 days, ηj.

Solve it with a child microwave! ! After that, it was heated and roasted.

Both boxes made from paper coated with polyetherimide and paper coated with a blend of polyetherimide and polyethylene terephthalate were in good condition with no deformation or discoloration observed when cooked in a microwave oven. .

Special W [Applicant: Toyobo Co., Ltd.

Claims (1)

[Claims] 1) A container for microwave ovens and/or open ranges formed from a sheet mainly composed of polyetherimide. 2) The container according to claim 1, which is formed from a sheet containing 60% or more of polyetherimide. 3) As a subcomponent, the glass transition point under 40-weight plate is 13.
2. The container according to claim 2, which contains an indestructible polymer having a temperature of 0° C. or higher. 4) The container according to claim 5, wherein the subcomponent is polycarbonate, which is a homopolymer or copolymer of tallate toma or polybutylene terephthalate. 7) The container according to Claims 1 to 6, which is formed by shallow drawing and deep drawing of a substantially unoriented sheet. 8) The container according to any one of claims 1 to 7, which is made of a sheet having a roughened surface and good printability. 9) The container according to claim 1, which is formed by shallow drawing or deep drawing from a sheet stretched to a magnification of 3 times or less in at least one direction. 10) A container for a microwave oven and/or an open range formed from a laminate in which a sheet mainly composed of polyetherimide and paper are laminated. 11) The container according to claim 10, wherein the laminate is obtained by impregnating or coating paper with a dope mainly composed of polyetherimide dissolved in a soluble organic solvent.