WO1991011083A1 - Material generating heat by absorbing microwaves - Google Patents

Abstract

This invention relates to a material which heats and cooks foods from outside by absorbing microwaves of an electronic range and by generating heat. A conductive substance or a nonconductive compound containing transition metals of atomic number 21-29 is mixed in a base material having an Fe group oxide as a principal component. Since the material has a rapid heat generating speed, the temperature in heat-generation is high, and further the material is cheap; it is effective as a material generating heat by absorbing microwaves.

Description

 Akira m Mark Mouth absorption heat generating material

Technical field

 The present invention relates to a micro wave absorbing and absorbing material which ripens by absorbing the energy of micro π-waves and has excellent heat generation characteristics especially in a microwave oven. Background technology

 In microwave ovens, irradiated microwaves apply vibrational friction to molecules such as water contained in the cooked food, and the temperature rises due to the heat. This has the advantage that cooking can be done in a short time.

 However, food cannot be cooked from the surface by conductive heat or radiant heat as in a gas cooker or resistance heater, so that the food surface can be given a scorching and quick-crispness (crisp feeling). I can't do that. Therefore, it was not suitable for cooking grilled fish, meat, pizza, etc. with scorch and crispyness.

 On the other hand, a method has been considered in which food is heated from the surface with a heating element made of a material that absorbs microwaves and generates heat using an existing microwave oven, thereby imparting charred or crisby properties.

However, the conventional heat generating material heating scan copy de is rather slow, not be sufficient as a heat generating material of the microwave oven which require rapid cooking _c present invention it has been made in view of the above problems The purpose is to raise the temperature in a shorter time than conventional heat-generating materials, and Z

Degree is high, a new microphone co-wave absorption onset ^ material Hisage ^ then, teeth and O and Ru _c

 Disclosure of the invention

 According to the present invention, the above object is attained by the following microwave absorbing heat generating material. That is,

 (1) Fe-based oxide Microwave absorption heat generating material characterized in that a conductive substance is mixed with Φ of the base material mainly composed of

 (2i The above-mentioned conductive material is a metal, an alloy, or a compound of a metal.

(3) said conductive material is F e, A £, C u , [:. R, \ i, T i, [S i, T i N, M o S i Σ, T i B 2, S i C Alternatively, the magic π-wave-absorbing heat-generating material according to the above (2), which is at least one of alloys and compounds.

 (4) A special feature is that a non-conductive compound in the compound of atomic number 21 to 29 © is mixed with a base material mainly composed of an Fe-based oxide. Microphone Mouth wave absorption heat generating material.

 (5) The O-mark ci-wave absorbing heat-generating material according to (4), wherein the non-conductive compound is an oxide.

 The micro wave absorption heat generating material of the present invention is obtained by mixing a conductive substance or a non-conductive compound of a transition metal having an atomic number of 21 to 29 into a base material containing an Fe-based oxide as a main component. Some are solidified. -

F e a base _{oxide, F e 0, F e 2} 0,. F e 3 0. F e 'alone G compound or F e. O is a complex oxide that is replaced by / 1 with another G metal element, but is also O.- A conductive substance means an inorganic or metal conductive substance. G) Metals such as' e, \ i, CG-. C r .. Mo, W-. A £, S, Cu-, _ g, A υ, Z n, D i, Z r, etc. , alloys walk C, S i C;. _ T i C, T 'i N - a _{T i B 2, Z r B} 2, M o S i t like O No machine substances, in appropriate alone, Alternatively, they can be mixed and used. This? Among them, F e, A £, C u, C r, K i. D i, C, S i T i N, MS iz, T i B z, S i C, etc. are practical. Strictly, the addition ratio of a certain conductive '] raw material varies depending on the material; does it vary ?. As a general rule of thumb, about 1 to 50 vol% of the Fe-based oxide base material The degree can be replaced. The conductive material is strongly mixed with the powder or ィ-':, and the particle size of the powder is preferably about 100 to 400 mesh. In the case of a fiber, a minor axis of 10 to 100 μm and a major axis of UK) m to 10 mm are appropriate.

The non-conductive compound of a transition metal of atomic number 21 to 29, these metals and 0, \ -.,, Also refers to _£ Naka those of a compound of B or the like of the non-conductive, the compounds of the 0 Is most desirable. The addition amount of these is preferably in the range of 0 to 0.5 mo 1 based on 1 m 01 of iron (Fe) in the base material;

That is, in the present invention, as described above, regardless of whether inorganic or metal, conductive compounds are generally effective, but non-conductive compounds of transition metal compounds having atomic numbers 21 to 29 are effective. There is that ₅

 Solidification of the Fe-based oxide of the base material and these conductive or non-conductive substances, molding into the required shape, sintering or, if necessary, cold curing type soldering. In the case of solidification by t-bonding achieved by using sintering, a sintering temperature of 800 to 1,200 200 is sufficient.

The following three are considered as the Mike mouthwave absorption and heat generation mechanism of the invention. In other words, ripening due to thermal loss, dielectric loss, and resistance loss-a conventional microwave absorbing and heating material, which absorbs microwaves due to its loss of properties. Fever. However, in the 20 'method, it is not possible to efficiently convert the energy of the microphone mouth wave into heat energy, and it is not possible to obtain a sufficient heat generation rate and heat temperature.

 マ イ The heat generation rate of the microwave absorption heat generating material in the invention is extremely high because the addition of the above-mentioned conductive or non-conductive substance causes the heat loss or the dielectric loss in addition to the magnetic loss due to the resistance loss. It is presumed that heat was induced by the heat. In addition,... In the present invention

According to the results of X-ray diffraction after heat generation, some materials were found to form oxides. It is considered that the heat of oxidation or thermisot reaction also contributed to the heat generation characteristics.

This oxidation reaction off We La wells force rather F _e3 0 _4, when the metal is F e, are considered following the reaction.

 F e — 1/2 0 z → F e 0

2 Fe + 3/2 0 ₂ → F e ₂ 0 ₃

3 Fe 0-1/2 0 _z → Fe ₃ 0 ₄

2 Fe 0-1/2 0 ₂ → F e ₂ 0 ₃

2/3 F e ₃ 04-1/6 0 ₂ → F e ₂ 〇 ₃

The telmisartan Tsu Bok reaction off, .- Rye preparative force F e ₃ 0 _4, when the metal or A £., Considered the following reaction.

1/3 F e ₃ 04 - is A / ₂ 0 ₃ addition aforementioned oxidation by reduced F e is considered _{- 2 A £ - 5/6 0 2} → F e.

The reaction heat is released by secondary and tertiary products of these reactions. After exit, further absorption of Mike mouth wave occurs and contributes to heat generation, but O and%: TL.

 BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a spear to curve heating characteristics upon addition of F e powder F e ₃ 0 ₄ powder.

FIG. 2 is a view to curve heating characteristics upon addition of A £ powder F e ₃ 0 ₄ powder.

Figure 3 is a curve showing the relationship between the added amount and the heat generation temperature of the various elements with respect to Fe 1 mol _c

 Fig. 4 is a curve showing the relationship between the sample plate thickness and the exothermic temperature-Best Mode for Carrying Out the Invention

(1) The Fe Konahitsuji to F e ₃ 04 powder 0, 5, 10, 15, 20 wt% added after mixed-and a 10 g pawl samples respectively excellent crucible thermal shock resistance. Next, the sample was microwave-heated in a microwave oven with a frequency of 2,450 MHz and an output of 750 W, and the surface temperature was measured using a radiation thermometer. Figure 1 shows the measurement results and results.

Heat release rate is increased by the this the addition of Fe powder As can be seen from Figure 1, while the required 5 minutes to heat generation temperature of the sample of Fe ₃ 0 ₄ plain reaches 500 'C, added Fe powder All of them took around 2 minutes. The maximum exothermic temperature also increased by about 100.

(2) F e ₃ 〇 ₄ powder F e, C u, C r , N i, T i, C, and S, T i N, M ύ S i 2, T i B ε, the S i C powder After addition of 5 wt%, the mixture was placed in the above-mentioned crucible, microwave-ripened in the microwave oven of Example (1), and the surface temperature was measured using a radiation thermometer. The heating temperature after the 2 minutes and Ί amount shown in Table 1 together with Fe ₃ 0 _{4. ?} As compared to any of the powder addition samples were also F e 0 ₄ plain sample, significant departure ripe properties were obtained: Moreover, these O added powder raw C, and exist Hatsujuku after X Ray be ώ observed It is only-. Μ 'S i ₂ S; C and C. Others are considered to have contributed to the ripening characteristics due to the heat generated by oxidation and the heat generated by secondary and tertiary products.

 Table 1 Ultimate heat temperature

_: Additive substance

 Minute

 F e 4 4 9 6 1

 '' Cu 4 1 δ δ 3

 C r: 4 3 δ: 6 20:

N i 3 4 ϋ _; 5 3 0:

 T i 4 9 2 6 3 4:

 ■ C 0 6 1.6. 10

 S i 0 8 δ 9 δ:

 : T i N 4 9 6 δ 0

 M 0 S i δ 30: 6 δ 4

: T i B _z 6 3 4: τ ο 3

 'SiC: 498-; 59 t

 3 2 δ 5 3 9

(3) Add 0-, 5710 wt% of A £ powder to Fe 0 powder and mix. After mixing, load on the above-mentioned crucible and use the electronic range of Example (1) Surface temperature was measured using a mature L radiation thermometer-the measurement results are shown in Figure 2. As shown in Fig. 2, when A £ powder is added so as to increase the heat generation rate in about 1 minute, the temperature rises rapidly. After the addition of 7 10 u-t%, the temperature dropped sharply and reached a constant around 500. Also, increase in the maximum heating temperature to the sample F e ₃ 0 ₄ plain sample of additive 5 7 wt% Te Ku label was observed.

(4) F e 3 0 4 powder with F e A £ T i N powder g if added 5 wt% of the powder and F e ₃ 0 ₄ Inorganic by Sunda scratch powder PLAIN to each 10 cm X 10 It was applied to a 200 cm thick ceramic sheet with a thickness of 200 m to form a heating element. As shown in Fig. 3, this was placed on a commercial frozen grater, and a cooking test was performed using the electronic range of Example (1), and the burnt surface and the cooking condition inside the food were observed. The results are shown in Table 2.

 Table 2

180 seconds 210 seconds 240 seconds 270 seconds:

; Additive substances

 Surface: Inside Surface: Inside Surface: Inside; Surface: Inside:

'F e △ △ /-: X

 'A £ △ Δ o; X' X X

'T i N Δ; △ 0 m ο; 〇, X:

 Δ;; Δ;;

 Δ insufficient cooking

 X overcooked

F e A ί-. T i added and heating element F e ₃ 〇: simple and short cooking time, 30 seconds with F e Ί 'i N added heating element, A £ added Heating element reduced cooking time by 60 seconds- f

 (5) Fer>) The powder is mixed with the oxide powder of i, Cr, VIri, Co-, Ni. Cu, Sτ. Ba by Fe 1 mo 1: element ratio with respect to From 0 to: mol 加, press-formed and baked at 800 to 1,200 · (: ^ 30 咖 to make a 52 mm plate. Then, using this sample, the frequency was 2,450Μ Η τ Microwave heating was performed for 30 seconds in a microwave oven with an output of 1,500 W, and the surface temperature was measured using a radiation thermometer.The measurement results are shown in Fig. 3-As can be seen from Fig. 1, The addition of oxides tends to increase the ripening temperature, but the force and the addition ratio are conversely reduced when the ratio exceeds 0.7 mol: in particular, T i, C r, M r, and C 0 , \ To. Cu-The material which added the oxide of the transition metal of the 4th period (atomic numbers 21 to 29) was obtained.

(6) F e ₃ 0 ₄ powder T i, C r, M n , C o, with respect to C u, S r, F e 1 mo 1 to B a © oxide powder, 0.3 mo 1 added in element ratio After pressing, the sample was baked at 800 to 1,200 mm, and the sample with a thickness of 1 to 8 mm was microwave-heated with the microwave oven of Example (5) for 30 seconds to obtain a radiation thermometer. The surface temperature was measured using. Fig. 4 shows the measurement results.

 In the case of adding the oxides of Sr and Ba, the exothermic temperature decreased as the thickness of the heating element became thinner, but in the case of adding the transition metal, high efficiency was obtained at most.

(7) F e ₃ 04 powder, T i, M n, the metal powder of S r was 0.3 mol added element ratio against the F e 1 m ol, was fired after press forming - with the sample was crushed, the the紛末with inorganic pi Nda 0.99 mm © heat衝擊resistance O strong yet crystallized glass _{(L i 2 0 - a i} 2 O 3 - S i O 2 system) quotes i ring on one side Jf- of 0.5 mm of To form a ripened body, which was then baked. Table 3 shows the measurement results obtained by measuring the surface temperature using a thermometer.

table

Additive element '. Average exothermic temperature

Ding i δ 1 1

Μ η 4 0 2

S r 3 1 4

In addition, put a commercially available frozen pizza of 1 150 mm on the above heating element and cook it with the above-mentioned electronic range, and cook the topping tool on the pizza surface and the pizza craft on the back surface The condition was observed. Table 4 shows the results.

 80 seconds 60 seconds 90 seconds:

 Inside; outside inside; outside inside; outside:

 'Attached Tim; Ο X X.

 : Addition

 Pit M η X ： X '

 : Elementary

 S r X X: good cooking

L: Insufficient cooking X: Overcooked

 The exothermic body to which T i and M n are added also has a high exothermic temperature:. Adds crispyness to the pizza craft even when cooking in Pisa:: Tochi; Cooked and had good flavor

 As described above in detail, the heat-generating material of the present invention has an extremely high heat-generating rate as compared with the conventional heat-generating material, and is effective in thawing frozen food and shortening the cooking time. In addition, since the exothermic temperature is high, it can be cooked in a smaller amount than conventional exothermic substances and is economical.

 Industrial applicability

 The material according to the present invention absorbs the microwaves of the microwave oven during microwave cooking and generates heat, so that it can be effectively used in microwave ovens as a material for cooking food from outside. can do.

Claims

I I  Scope of Claim Microwave-absorbing heat-generating material characterized in that a conductive substance is mixed in a base material mainly composed of an Fe-based oxide. 2. The heat-absorbing and heat-absorbing material according to claim 1, wherein the conductive substance is a metal, an alloy or a compound of a metal. . The conductive material is F e, A £, C u , C r, is i, Ding i., C, S i, T i N N M o S i z, T i B 2, S i C or they 3. The microwave absorbing heat generating material according to claim 2, wherein the material is at least one kind of alloy or compound. Micro mouth characterized in that a non-conductive compound among transition metal compounds of atomic numbers 21 to 29 is mixed in a base material mainly composed of an Fe-based oxide. Wave absorption heating material. 5. The heat absorption material according to claim 4, wherein the non-conductive compound is an oxide.