JPS6387534A - Container for microwave cooking - Google Patents

Abstract

PURPOSE:To produce various kinds of properly scorched parts of foods and to prevent damage of a container, by a method wherein a printed film, formed by printing with an ink composition containing potassium titanate reductant and metallic particles which reflect microwaves, is used as a heat generating substance. CONSTITUTION:By irradiating a print film, being a heat generating substance, with microwaves, both a heat generating effect, produced by absorbing microwaves by potassium titanate reductant, and a heat generating effect, produced by a resistance loss, are effectively produced. Simultaneously, microwaves are reflected by metallic particles dispersed in the printed film, a food is effectively heated, and a scorched part can be produced efficiently and properly. By controlling printing concentration of the heat generating substance, desired temperature can be obtained to a high temperature, therefore sudden heating is prevented from occurring due to selection of printing concentration, and a heat generating substance, generating heat high enough to produce a properly scorched part, can be formed. Thus, a container is not limited to a heat resistant glass container, and even various package containers, e.g. paper containers, plastic containers, can be applied without being damaged.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a food container for microwave cooking, and more specifically to a microwave cooking container that heats food, turns the outer surface of the food brown, and further controls the heating. Concerning food containers for wave cooking.

[Conventional technology]

In general, microwave ovens are used to cook food using high frequency waves of about 2450 MHz, and have the advantage of being able to cook food quickly and hygienically, so they are widely used.

When cooking using high frequency waves in such a microwave oven, the cooked food does not have burnt marks. Therefore, for example, when foods such as gratin, pizza pie, and dumplings require browning, they should be heated in a microwave oven using a regular container. The law is inadequate.

Therefore, microwave cooking utensils are made by coating the walls of containers made of heat-resistant dielectric materials such as heat-resistant glass with a metal film, and microwave absorbing coatings such as magnetic powder are coated on the walls of containers such as paper or aluminum foil. A microwave cooking utensil has been proposed.

The bottom surface of the container is further provided with a layer of conductive elemental metal such that when exposed to microwave radiation, the metal layer heats and partially browns the food in the container; It has also been proposed to eliminate the reflection of microwaves on the surface of the metal layer by forming the layer into a thin film by vacuum evaporation (see Japanese Patent Publication No. 15548/1983).

[Problem that the invention seeks to solve]

However, the heating method that utilizes the heating effect of the first resistor (heat generation due to resistance loss) generates a very high temperature, so it cannot be applied to containers made of paper, for example, unless the container is made of heat-resistant glass or the like.

Next, the second heating method that utilizes magnetic loss cannot achieve a sufficient temperature rise.

Furthermore, the third metal layer must be made into a thin film using vacuum deposition technology, and cannot be mass-produced at low cost. Furthermore, it is not possible to create pattern-like or mesh-like patterns.

Therefore, the problem to be solved by the present invention is that it is possible to apply burnt marks in a pattern or in a mesh pattern, and it is possible to apply the burnt marks appropriately, and it is possible to apply burnt marks in a suitable manner. To provide a food container that operates using microphone A wave harmonics without damaging the container and which can be mass-produced at low cost.

[Means for solving problems]

As a result of research to solve the above-mentioned problems, the inventor of the present invention found that by using a printed film formed by printing using an ink composition containing a reduced potassium titanate as a heating element and metal particles that reflect microwaves. , Karu Dejima's findings showed that it was possible to create a material that could be burnt to an appropriate degree, that it could be applied even when the packaging material was paper, that it could be patterned with burnt marks, and that it could be mass-produced at low cost by printing. The present invention has been completed based on this.

That is, the microwave cooking container of the present invention is a food container used for microwave cooking of foods, in which potassium titanate reductant and microorganisms are added to a partial area of the container wall surface of the container body or a partial area of the lid. The gist of the present invention is ``a container for microwave cooking characterized by being provided with a printed coating formed by printing using an ink composition containing gold particles that reflect waves.''

Therefore, in the present invention, paper,
Or paper, aluminum, or plasti.

Composite materials such as carbon film, or plastic films relatively stable against heat such as polyester or nylon may be used.

Next, as an ink composition containing a reduced potassium titanate and metal particles that reflect microwaves, a reduced potassium titanate (K2O.nTiO2-1) and metal particles that reflect microwaves are mixed with polyethylene.

An ink composition blended with a resin or polyester such as polyurethane, nylon, polyimide, polybenzimidazole, or polyamideimide can be applied.

The reduced potassium titanate preferably has an average fiber length of 5 to 50 μm and a fiber diameter of 0.05 to 2.0 μm. Next, examples of metal particles that reflect microwaves include aluminum, 2, and Kel, which have a microwave reflectance of 50 to 100%.

Metal particles such as iron, tin, and zinc are effective.

Next, it is desirable that the mixing ratio of the reduced potassium titanate and metal particles in the ink composition is such that the concentration of the metal particles is less than or equal to the concentration of the reduced potassium titanate.

Furthermore, the surface resistance of the printed film can be adjusted by changing the ink composition and coating amount;
~10! It is desirable to set it to Ω/cIA. 10-1
When it is less than Ω/-, the heat generation temperature is too high and there is a risk of ignition.

On the other hand, when it is 10'''Ω or more, the heat generation temperature is low and it cannot be put to practical use.

A protective layer such as a relatively heat-stable plastic such as polyester, polyethylene, nylon, cellophane, or polysulfone may be provided on the printed coating.

[For production]

When microwaves are irradiated onto the printed film, which is a heating element, both the heat generation effect due to microwave absorption of the reduced potassium titanate and the heat generation effect due to resistance loss are produced.
Microwaves are reflected by the metal particles dispersed in the printed film, and the food is effectively heated, allowing for efficient and appropriate browning.

〔Example〕

Examples 1-6. and Comparative Examples 1 to 4 Potassium titanate reduced body (K20-nTi 02-1
) and aluminum or nickel metal particles together, 30! Using an ink composition containing t% and using polyurethane as a binder, a polyester film of 12μ
A printed coating having a coating amount of 100 liters was printed on the surface of the sample using a gravure printing method.

Next, the printed polyester film was attached to a coated paper having a basis weight of 400 P/m'' using an incyanate adhesive so that the printed film surface faced the coated paper surface.

Put the work done in the above way into a home microwave oven.
A glass petri dish containing 30 cc of salad oil with an FC temperature of 23°C was placed on the polyester film prepared above, and the temperature rise of the salad oil when irradiated with microwaves was measured over time by AaEA Co., Ltd. (Sweden) Measured using a back wall optical fiber thermometer.

A graph showing the temperature rise of salad oil over time when a glass petri dish containing 30CC was placed and irradiated with microwaves.
Measurement was performed using a back wall optical fiber thermometer manufactured by aEjinsha (Sweden).

Table 1: Relationship between ink composition and temperature rise The test results are shown in the table above.

The above measurement results show that the heating efficiency is better when both the reduced potassium titanate and metal particles are fed than when only the reduced potassium titanate is used, and that the reduced potassium titanate is more effective than the metal particles. It was found that the heating efficiency was better when a large amount of potassium titanate was contained than when the reduced potassium titanate was contained less than the metal particles.

Example 7 Figure 1 shows a pizza carton.

Paper 100P/rr? The bottom region (2) of a carton (1) made of a composite material of
3) Using an ink composition containing 20% by weight and 10% by weight of aluminum metal particles and polyurethane as a binder, the coating amount was 109/rr? by gravure printing method.
A printed coating (3) was formed by printing.

Microwave irradiation was performed for 30 seconds in a 500W microwave oven.

The exothermic temperature was 250°C.

Then put the pizza ingredients into the carton box.
When heated for 0 seconds, it was possible to cook with moderate browning.

Example 8 The same procedure as in Example 7 was carried out, except that the printed film was formed in a grid pattern (FIG. 2).

Example 9 A printed film was formed in a pattern in the same manner as in Example 7 (FIG. 3).

A bob corn could be made by using the same reduced potassium titanate as in Example 7 and heating it in a microwave oven with the microwave opening closed using polyester as a base material.

Example 11 Printed coatings (3) containing reduced potassium titanate and microwave-reflecting metal particles were provided at regular intervals on one side of a polyester film (6) as shown in Figure 5.

When a rice ball was wrapped in the polyester film (6) thus formed and heated in a microwave oven, a pattern of burnt marks could be formed around the rice ball.

〔Effect of the invention〕

As detailed above, according to the microwave cooking container of the present invention, there is a heat generation effect due to the absorption of microwaves by the potassium titanate reductant in the printed coating, and a resistance loss due to the electrical conductivity of the printed coating. The synergistic effect of both the heating effect of the metal particles and the microwave reflecting effect of the metal particles makes it possible to heat food efficiently.
You can add a moderate amount of darkening.

Further, the device according to the present invention has the advantage that the heating element can be formed into any pattern by printing. For this reason, (1) heat things you want to heat and things you don't want to heat separately, (11) attach a wire mesh or a branding iron, or (Ill) combine it with conventional differential heating to synergistically reduce temperature differences. You can also do things like

Furthermore, since the heating element according to the present invention can be formed by printing, a desired heating temperature can be obtained by controlling the printing density of the heating element.

For this reason, by selecting the printing density, it is possible to form a heating element that generates heat to the extent of moderately browning without being rapidly heated. It can be applied to various packaging containers such as plastic, plastic, and re-molded containers.

Furthermore, the container of the present invention has the advantage that it can be mass produced by printing at a lower cost than by vacuum deposition.

[Brief explanation of the drawing]

1 to 3 are developed views of cartons of Examples 7 to 9, FIG. 4 is a perspective view of Example 10o, and FIG. 5 is a sectional view of Example 11. Figure 1 Figure 2 Figure 3

Claims (4)

[Claims] (1) In a food container used for microwave cooking of food, an ink composition containing a potassium titanate reductant and metal particles that reflect microwaves in a partial area of the container wall surface of the container body or a partial area of the lid body. A container for microwave cooking, characterized in that it is provided with a printed film formed by printing using a material. (2) The microwave cooking container according to claim 1, wherein the metal particles that reflect microwaves have a microwave reflectance of 50 to 100%. (3) The microwave cooking container according to claim 1, wherein the printed film contains a larger amount of reduced potassium titanate than the metal particles that reflect microwaves. (4) The printed film is 10^-^1~10^3Ω/cm
The microwave cooking container according to claim 1, which has a surface resistance of ^2.