JPH0378991A - Mica heater - Google Patents

Abstract

PURPOSE:To enhance the quick heating property by applying a surface treatment excellent in heat radiation and non-stickiness to the surface of laminated mica containing silicon type varnish in a content over 20wt.% corresponding to the heat conduction surface. CONSTITUTION:Laminated mica 1a, 1b containing silicon type varnish in a content over 20wt.% is used, and a surface treatment 3 excellent in the heat radiation and non-stickiness is applied at least to the surface of the laminated mica 1a corresponding to the heat conduction surface. As high a content of varnish as exceeding 20wt.% will enhance the mechanical strength of laminated mica and the inter-layer strength between mica particles, and this surface treatment excellent in heat radiation and non-stickiness applied to the heat conduction surface of mica heater enables use in directly exposed condition. This will enhance the quick heating property.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a mica heater used in a toaster, and more particularly to a mica heater that has excellent rapid heating properties.

BACKGROUND OF THE INVENTION Mica heaters have been widely used as heating sources for home appliances because they are inexpensive and can be easily molded into various shapes.

This mica heater is generally manufactured and used by placing a mica plate around which a ribbon-shaped heating element is wound between a pair of mica plates, and integrating the mica plates with an eyelet or the like.

Recently, scissor-grilled toasters, which have been in the spotlight, use the above-mentioned mica heater, and are used by sandwiching and integrating the mica heater with aluminum plates or the like.

On the other hand, in addition to the conventional type of mica heater that uses the three mica plates mentioned above, recently, a sheet-shaped heating element is sandwiched between two mica plates pre-impregnated with a binder, hot pressed, and electrified. Mica heater
1-13590, etc.) have also been used.

Problems to be Solved by the Invention However, when used as a heating source for products, both conventional mica heaters and mica heaters obtained by recent new manufacturing methods, they are fixed with aluminum plates, etc., and therefore the temperature rises. It is slow and has problems as a heating source for products that require a certain degree of cooking speed, such as scissor-grilled toasters.

For this reason, some research has been conducted in which the mica heater is directly exposed without using this aluminum plate, and bread is brought into contact with the mica heater to toast the bread, but there are problems with the mechanical strength of the mica plate and various problems such as burning of the bread. Problems arose, and it has not been possible to put it into practical use.

The present invention aims to solve the above-mentioned conventional problems and provides a mica heater with excellent rapid heating properties.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a composite mica containing 20% by weight or more of a silicon-based face, and also provides thermal radiation to at least the surface of the composite mica that corresponds to the heat transfer surface. This is achieved by applying a surface treatment with excellent non-adhesive properties.

Function: Conventionally, silicone-based fibers have been commonly used as a binder for aggregated mica, and the amount added has been around 10% by weight.

For this reason, the mechanical strength of aggregated mica is not at a level that poses a significant problem in practical use, but it cannot be said to be very strong.

In addition, if a surface treatment such as heat-resistant coating is applied to the surface of laminated mica, the treatment is possible, but delamination easily occurs between the mica particles, so the adhesion strength of the coating film is extremely weak, making it difficult to use in actual use. It wasn't something.

However, in the present invention, by increasing the amount of silicon-based face added to 20% by weight or more, the mechanical strength of the above-mentioned aggregated mica and the interlayer strength between mica particles could be significantly increased.

Therefore, the heat transfer surface of the mica heater can be subjected to a surface treatment with excellent heat radiation and non-adhesive properties, and can be used in a directly exposed state.

As a result, the temperature rises significantly faster than in the case of fixing and holding with conventional aluminum plates, and rapid heating properties can be ensured.

The present invention can be applied to a conventional mica heater using three mica plates as well as a recent mica heater using two mica plates.

Furthermore, there are two types of aggregate mica: soft mica and hard mica, and the present invention can be applied to either case.

EXAMPLE Hereinafter, a specific example of the present invention will be described based on FIG.

Two laminated mica plates (size 150 x 250
A sheet-like heating element 2 made of stainless steel was placed between nu++)la and 1b, and they were integrated by hot pressing.

Subsequently, surface treatment 3 was applied to the surface of the laminated mica board 1a using a silicone heat-resistant coating containing a fluororesin to prepare mica heaters of sample numbers 1 to 7.

On the other hand, as shown in Fig. 2, a laminated mica plate similar to that of sample number 2 was used, and a mica heater without surface treatment was coated with 0,
A conventional mica heater of sample number 8 to which a 3t aluminum plate 4 was fixed was also prepared.

(Margins below) The mica heaters of sample numbers 1 to 8 prepared in this way were evaluated in terms of three items: ■ mechanical strength ■ adhesion strength of surface treatment ■ toast cooking time.

■ Mechanical strength was evaluated by pressing a load of 3 kg onto the center of the mica heater and determining whether it would break. The results are shown in Table 1. An x mark indicates that damage was observed, a Δ mark indicates that no damage was observed but large deformation was observed, and an O mark indicates that neither damage nor deformation was observed.

■ The adhesion strength of the surface treatment was evaluated by applying cellophane tape to the surface-treated laminated mica board and rapidly peeling off the cellophane tape to see if any peeling occurred. The results are also shown in Table 1.

An x mark indicates that peeling occurred, and a circle mark indicates that no peeling occurred.

■ Toast cooking time was evaluated by placing the mica heater horizontally, placing two slices of bread cut into 6 pieces on top, and inputting 400W of power consumption until the bread on the side of the mica heater was just toasted. . The cooking times at this time are also shown in Table 1.

As is clear from Table 1, the mica heaters of the present invention with sample numbers 4, 5, 6, and 7 take less than 2 minutes to cook toast, compared to the conventionally used mica heater with sample number 8. It was possible to toast extremely quickly and quick heating properties were obtained.

Furthermore, it was excellent in mechanical strength and adhesion strength in surface treatment, and exhibited properties that would cause no problems in practical use even without using an aluminum plate or the like.

Although soft mica powder was used in the examples of the present invention, the present invention is not particularly limited to this, and hard mica powder may also be used.

Furthermore, the present invention may be applied to a mica heater using a mica plate around which a conventional ribbon-shaped heating element is wound.

Effects of the Invention As is clear from the above explanation, according to the mica heater of the present invention, a composite mica containing 20% by weight or more of a silicon face is used, and at least the surface of the composite mica corresponding to the heat transfer surface is By applying surface treatment with excellent heat radiation and non-adhesive properties, it is possible to provide a mica heater with excellent rapid heating properties.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a mica heater according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional mica heater according to the same embodiment. 1a, 1b... assembled mica, 2... heating element, 3... surface treatment, 4... aluminum plate.

Claims (1)

[Claims] A mica heater using a mica composite containing 20% by weight or more of silicone varnish, and in which at least a surface of the mica composite corresponding to a heat transfer surface is subjected to a surface treatment to provide excellent heat radiation and non-adhesion.