JPH01148213A - Heating accelerator for microwave cooking - Google Patents

Abstract

PURPOSE: To improve heat resistance of a heating acceleration material itself for providing burnt marks on food and accelerating heating food by applying metal plating at least on one face of a sheet consisting of a heat-resistant insulating material. CONSTITUTION: It is necessary to provide a heat-resistant insulating sheet at least on one face of an electrically-conductive sheet for giving it a roll of a protective layer for avoiding to bring food into contact with the electrically- conductive sheet and for purposes of providing wetting resistance and of insulating the electrically-conductive sheet from air to prevent the sheet from taking fire. For example, it is a heating acceleration material for microwave cooking wherein heat generating effect is given by radiating a sheet to which electric conductivity is provided by applying metal plating by means of an electroless plating method with microwave. As the sheet provided with electric conductivity, a non-combustible paper prepd. by compounding an inorg. filler to a cellulose pulp, etc., are used. As a method for applying metal plating for providing electric conductivity to the sheet, an electroless plating method which can plate an insulating material is pref. used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disposable food package. In particular, it relates to materials for browning foods when cooking them using microwaves to obtain a flavor similar to that of conventional cooking methods, and for accelerating the heating of liquid foods such as soups.

[Conventional technology]

Conventionally, cooking with microwaves has not been able to brown foods like normal cooking, and the flavor has not been as good as with normal cooking methods.

For this reason, conventional efforts have been made to promote heating to brown the food by incorporating a film or layer into the food container that is particularly heated by the microfluid. For example, a thin layer of a semiconductor such as tin oxide is applied to a ceramic container (JP-A-50-9132, JP-A-50-913).
3), examples of applying edible substances that easily brown such as disaccharides to the food itself (JP-A-51-95144, JP-A-51-95145), and evaporation of an aluminum film onto a base sheet. (Japanese Unexamined Patent Publication No. 53-99280), an example using a carbonaceous body to be heated (Japanese Unexamined Patent Publication No. 56-4)
2022, Japanese Unexamined Patent Publication No. 56-44534), and an example using a very thin conductive film (Japanese Patent Publication No. 60-15548).

However, these methods have problems in that sufficient heating effects and browning are not achieved, the heating element itself burns due to the heat generated, and it is also expensive.

[Problems to be Solved by the Invention] An object of the present invention is to provide a disposable, inexpensive food container material. Furthermore, another object of the present invention is to provide a heating accelerator with improved heat resistance that browns food and accelerates heating of the food in microwave cooking, and prevents the heating accelerator itself from burning. Then there is k.

[Means for solving problems]

The present invention provides at least one side of an electrically conductive sheet which is provided with a higher electrical conductivity by metal plating.

This is a heating accelerator for microwave cooking provided with a protective layer made of heat-resistant insulating S/).

That is, the present invention is a heating accelerator for microwave cooking, in which a sheet is plated with a metal by electroless plating to give it conductivity, and the sheet is heated so as to have a heat generating effect by radiating microwaves.

The heating accelerator of the present invention can be used as a container or a part of a container for cooking food using microwaves such as a microwave oven. For example, it can be used as a food container itself, such as a container used as a plate to brown food such as pie, and other ways to use it include placing food on the heating accelerator of the present invention. You can also heat it by placing a container on it.

Furthermore, when cooking liquid foods such as soup in a microwave oven, liquid foods usually do not cause convection. As a result, for example, noodles were not sufficiently loosened] and soups were not mixed sufficiently. However, when the sheet obtained according to the present invention is used at the bottom of a food container, the food is heated from below, making it possible to generate convection currents.

In the present invention, the conductive sheet may be non-combustible paper made of 7μ loin pulp mixed with an inorganic filler, synthetic paper or nonwoven fabric made of 7μ loin pulp, heat-resistant synthetic fibers, and inorganic fibers, or PICT fiber. Heat-resistant films such as μm, inorganic sheets such as amina silica sheets, etc. are used.

Among these sheet materials, the 7μ loin pulp used for forming non-combustible paper includes ()P (ground wood pulp), RMP (refiner mechanical pulp), TMP (thermonical pulp), and 0GF (chemigerand powder μde). ), 5ep (semi-chemical pulp), SP (sumufido pulp), K
P (kraft powder), AP (alkali vapor), waste paper valve (deinked secondary fiber), linter pulp, etc. are used alone or in combination.

In addition, 7 μ loin pulp is the main ingredient, as well as natural fibers such as cotton, chemical fibers such as rayon, polyvinyl μ-cop fibers, polyester, polyacrylonitrile μ, various synthetic pulps such as polyethylene and polypropylene, asbestos, rock wool, etc. It may also be a 7μ loin bulb containing inorganic fibers such as glass fibers.

Inorganic fillers include aluminum hydroxide, dawsonite, μsium hydroxide, magnesium hydroxide, μsium rehydrate, gypsum, calcium aluminate, zinc oxalate, barium oxalate, and sand. , kaolin clay, alum stone, basic magnesium carbonate, and other inorganic hydrous compounds;
Asbestos, perlite, antimony oxide, red ash, molybdenum-containing compounds, etc. can be used.

The blending ratio of these inorganic fillers and the fibrous material mainly composed of cellulose binder is inorganic filler/fibrous material = 10/90~
The range is 90/10.

The mixed synthetic fiber paper and nonwoven fabric include heat-resistant synthetic fibers such as the aforementioned 7μ loin fiber, polyester lv fiber, acrylonitriμ fiber, phenolic fiber, fluororesin fiber, meta- or rose-aramid fl fiber, polyamide-imide fiber, and Mixed synthetic paper and nonwoven fabric made of one or a combination of inorganic fibers such as alumina fiber, rock wool, asbestos fiber, and glass fiber are used.

Fillers may also be added to these mixed synthetic fiber papers and nonwoven fabrics in order to impart nonflammability.

In this case, the filler is not particularly limited and any filler commonly used in paper making can be used.

Inorganic water-containing materials such as aluminum hydroxide, dawsonite, hydroxide, magnesium hydroxide, mineral hydroxide, zinc balate, barium balate, sand, kaolin clay, calcium carbonate, alum stone, and basic magnesium carbonate. Examples include compounds such as silica, calcium aluminate, asbestos, perlite, antimony oxide, red ash, and molybdenum-containing compounds.

The conductive sheet used in the present invention may be formed by any method, but dry or wet paper-making methods, which are normally used for manufacturing nonwoven fabrics, paper, etc., can be suitably used. .

In the wet papermaking method, other papermaking aids such as a paper strength enhancer, a sticky agent, a sizing agent, etc., which are commonly used, can also be appropriately used as necessary.

As a method for applying metal plating to impart conductivity to the sheet, an electroless plating method that can plate an insulating material is advantageously used.

The metal used for plating is preferably a metal that has high conductivity and does not cause deterioration such as oxidation, and a metal that is safe to handle. The metals you have can be easily used. Nickel, copper, copper, silver, gold, platinum, etc. can be listed as representative metals that are easy to use, and these metals can be used alone or in combination.

Others include aluminum, iron, lead, zinc, tin, chromium,
Any metal such as cadmium can be used. Copper, aluminum, nickel, etc. are easily oxidized and deteriorated, but this can be compensated for by providing another metal layer on the outside that is resistant to oxidation and deterioration. Oxidation and deterioration can also be prevented by laminating the film to block air.

Although the amount of plating varies depending on the type of metal, it is sufficient that the surface electrical resistance value of the conductive sheet is in the range of 1 to 10 Ω, and for this purpose, the thickness of the plating may be 11 to 2 μmK.

The heat-resistant insulating sheet serves as a protective layer to avoid contact between the food and the conductive sheet, and also blocks air to prevent the conductive sheet from catching fire. For this purpose, it is necessary to provide it on at least one side of the conductive sheet. Examples of the heat-resistant insulating sheet include resin films made of polyesters such as polyethylene terephthalate, borisaphon, polymethylpentene, or methyμpentene copolymers. The heat-resistant insulating sheet can be provided on the conductive sheet by any method such as dry lamination or extrusion lamination. Furthermore,
At that time, in order to improve adhesiveness, an anchoring agent may be applied or activation treatment such as corona treatment may be performed.

〔Example〕

Hereinafter, the present invention will be explained in more detail using examples.
The present invention is not limited to these examples.
A conductive sheet was prepared by applying steel plating to a 2509/m'' sheet consisting of 50% by weight of copper by the following electroless plating method.

The sheet was immersed in a Budge Lamb colloidal solution (MOA-85, manufactured by Nako Electronics Co., Ltd.) as a catalyst for 4 minutes, and then washed with running water for 1 minute. Next, a borohydrofluoric acid solution (the same company, M
AL-200) for 4 minutes to activate the catalyst on the sheet surface, then rinsed with running water for 1 minute, and then soaked in copper plating solution (Al-200) for 4 minutes to activate the catalyst on the sheet surface.
MCR-1SO) for 20 minutes to provide copper plating.
A conductive sheet was created. The thickness of the plating on the surface of the conductive sheet was 12 μm.

Furthermore, it was confirmed using a scanning electron microscope that copper had penetrated into the inside of the conductive sheet.

Polyester (PFiT) was applied to both sides of the obtained conductive sheet.
) The film was extruded and laminated so that one side had a thickness of 25 μm to obtain a heating accelerator for microwave cooking.

The obtained heating accelerator for microwave cooking was formed into a circular shape with a diameter of 4 strokes, and this was stuck to the bottom of a paper cup using an adhesive. At this time, a thermocouple was inserted between the two and used for temperature measurement.

A paper cup was filled with 50°C of water at <20°C and heated for 15 seconds in a commercially available microwave oven, and the temperature was measured using an inserted thermocouple. The results are shown in Table 1.

Example 2 Example 1 except that nickel was used as the plating metal
A conductive sheet was prepared in the same manner as above.

The nickel plating solution is anhydrous nickel chloride μm1moA.
, ammonia 2. Omot and sodium hyposinite C
L 1 mot made up to 1 liter with water was used.

Next, in the same manner as in Example 1, PET films were extruded and laminated on both sides of the conductive sheet to a thickness of 25 μm to create a heating accelerator for microwave cooking. Hereinafter, the performance of the sample was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example & A conductive sheet was prepared by applying copper plating to a 60 μm thick PET film by electroless plating in the same manner as in Example 1.

The immersion time in the copper plating solution was 7 minutes.

Hereinafter, a heating accelerator for microwave cooking was prepared in the same manner as in Example 1, and its performance was evaluated. The results are shown in Table 1.

Example 4゜Thickness 2ws alumina silica) t-80℃ (7) 1
．． After immersing in an aqueous solution of sodium 5-thiphosphate for 5 minutes, washing with running water, and then using an etching solution at 40°C (98-thionitric acid 30
(10 parts of 46% hydrogen fluoride, 60 parts of water) K10
The surface was etched by dipping for a minute, and then washed with running water, and then copper plated in the same manner as in Example 1 to produce a conductive sheet.

Hereinafter, a heating accelerator for microwave cooking was prepared in the same manner as in Example 1, and its performance was evaluated. The results are shown in Table 1.

As a comparative example, a sample laminated with a PET film was prepared in the same manner as in Example 1 using the sheet used in Example 1 but not imparted with conductivity, and its performance was evaluated. The results are shown in Table 1.

Table 1 As is clear from Table 1, the sample using the conductive sheet of the present invention has a superior heat generation effect compared to the comparative example using the non-conductive sheet. I understand that.

〔Effect of the invention〕

The heating accelerator for microwave cooking of the present invention can be obtained by applying a small amount of metal plating to the surface of a sheet made of a heat-resistant material. It is possible to inexpensively produce a heating accelerating material that promotes heating and also prevents the heating accelerating material itself from burning.

Patent applicant: Oji Paper Co., Ltd.

Claims (1)

[Claims] 1. A heating accelerator for microwave cooking, comprising a protective layer made of a heat-resistant insulating sheet on at least one side of a conductive sheet that has been made conductive by metal plating.