CN102254651A - Preparation method of heat-conducting insulating material for resistance wire heating disc - Google Patents

Abstract

The invention discloses a preparation method of a heat-conducting insulating material for a resistance wire heating disc. The method comprises the following steps of: crushing electrically fused magnesium oxide with the purity of not less than 95 percent into magnesium oxide powder with different particle sizes of 50 to 60 meshes, 60 to 80 meshes, 80 to 140 meshes, 140 to 200 meshes, 200 to 325 meshes and 200 to 320 meshes; mixing the magnesium oxide powder with the different particle sizes according to weight ratios of 25 percent, 20 percent, 25 percent, 15 percent, 10 percent and 5 percent sequentially; deironing, drying and adding 2 to 4 percent of mullite powder or spinel powder; and finally, adding 5 to 10 percent of epoxy resin. The heat-conducting insulating material prepared by the method is made into the resistance wire heating disc, and has low induction voltage and leakage current and high using safety.

Description

A kind of resistance wire heat-generating disc preparation method of heat-conducting insulation material

Technical field

The present invention relates to electrical insulating material, be specially the preparation method of a kind of resistance wire heat-generating disc with heat-conducting insulation material.

Background technology

Owing to can produce harmful radiation during electromagnetic oven, microwave oven use, gas burner exists and leaks hidden danger, and that the resistance wire heat-generating disc has is safe in utilization, neatly, quick heating, temperature height, advantage such as cost performance is outstanding makes it be widely used in kitchen cooker and industrial compact heat source.

The resistance wire heat-generating disc is to place the rated resistance silk in metal dish, around resistance wire, fill, coat with heat-conducting insulation material, by exert pressure, moulding, solidify through high temperature sintering again and make.The heat-conducting insulation material that present heat-generating disc uses is silica and talcum powder.The shortcoming of the heat-generating disc ubiquity induced voltage height of manufacturing with this class material (more than the 110V), leakage current big (more than the 0.3mA), safety in utilization difference is hung back many users.

Summary of the invention

The objective of the invention is provides the preparation method of a kind of resistance wire heat-generating disc with heat-conducting insulation material at the shortcoming of above-mentioned prior art.Heat-conducting insulation material with this method preparation is manufactured the resistance wire heat-generating disc, can reduce the induced voltage and the leakage current of heat-generating disc, improves its safety in utilization.

The resistance wire heat-generating disc provided by the invention preparation method of heat-conducting insulation material may further comprise the steps:

(1) purity is not less than 95% electrically molten magnesia and pulverizes, sieve into 50-60 order, 60-80 order, 80-140 order, 140-200 order, 200-325 order and the varigrained magnesia powder of-320 orders;

(2) varigrained magnesia powder of (1) step is taken by weighing by 25%, 20%, 25%, 15%, 10% and 5% weight ratio successively, mix;

(3) magnesia powder with (2) step carries out deironing;

(4) magnesia powder after (3) step deironing was dried by the fire 45 minutes under 300 ℃ of temperature;

(5) add mullite powder or spinel powder in the magnesia powder after the oven dry of (4) step, the granularity of mullite powder and spinel powder is the 100-200 order, and addition is the 2-4% of magnesia powder weight, and mixing;

(6) add epoxy resin in (5) material in step, addition is the 5-10% of weight of material, and mixing is resistance wire heat-generating disc heat-conducting insulation material.

The resistance wire heat-generating disc that uses heat-conducting insulation material of the present invention to manufacture has the following advantages:

1, intensity height freely falls from the 70cm eminence, and is whole excellent, do not have cracking;

2, induced electricity forces down, and below 80V, existing resistance wire heat-generating disc reduces nearly 30%;

3, leakage current is little, below 0.1mA, less than 1/3rd of existing resistance wire heat-generating disc;

4, room temperature resistance infinity, compressive resistance 〉=2500V,

5, safe and reliable.

Embodiment

Embodiment 1

Prepare resistance wire heat-generating disc heat-conducting insulation material according to the following steps:

(1) getting purity is that 95% electrically molten magnesia is pulverized, and sieves into 50-60 order, 60-80 order, 80-140 order, 140-200 order, 200-325 order and the varigrained magnesia powder of-320 orders;

(2) above-mentioned varigrained magnesia powder is taken by weighing by 25%, 20%, 25%, 15%, 10% and 5% weight ratio successively, mix;

(3) utilize the above dry-type magnetic extractor of magnetic field intensity 18000GS that the magnesia powder in (2) step is carried out deironing;

(4) magnesia powder after the deironing was dried by the fire 45 minutes under 300 ℃ of temperature, remove wherein moisture and fugitive constituent;

(5) add the mullite powder in the magnesia powder after oven dry, mullite powder degree is 150 orders, and addition is 3% of a magnesia powder weight, mixing;

(6) add epoxy resin in the material in (5) step, addition is 7% of a weight of material, and mixing makes resistance wire heat-generating disc heat-conducting insulation material of the present invention.

Add solvent toluene in above-mentioned heat-conducting insulation material, addition is 5% of a weight of material, is filled at twice behind the mixing in the heat-generating disc, and resistance wire is coated, and through exerting pressure, moulding is solidified through 400 ℃ of high temperature sinterings again, promptly can be made into the resistance wire heat-generating disc.

After testing, the induced voltage of this heat-generating disc is 75V; Leakage current is 0.08mA.

Embodiment 2

(1), (2), (3), (4), (6) step be identical with embodiment 1, only changes additive mullite powder into spinel powder in (5) step, and be surplus all identical.

The resistance wire heat-generating disc that utilizes this heat-conducting insulation material to manufacture, after testing, its induced voltage is 78V; Leakage current is 0.05mA.

Claims (1)

1. a resistance wire heat-generating disc is characterized in that this method may further comprise the steps with the preparation method of heat-conducting insulation material:

(1) purity is not less than 95% electrically molten magnesia and pulverizes, sieve into 50-60 order, 60-80 order, 80-140 order, 140-200 order, 200-325 order and the varigrained magnesia powder of-320 orders;

(2) varigrained magnesia powder of (1) step is taken by weighing by 25%, 20%, 25%, 15%, 10% and 5% weight ratio successively, mix;

(3) magnesia powder with (2) step carries out deironing;

(4) magnesia powder after (3) step deironing was dried by the fire 45 minutes under 300 ℃ of temperature;

(5) add mullite powder or spinel powder in the magnesia powder after the oven dry of (4) step, the granularity of mullite powder and spinel powder is the 100-200 order, and addition is the 2-4% of magnesia powder weight, and mixing;

(6) add epoxy resin in (5) material in step, addition is the 5-10% of weight of material, and mixing is resistance wire heat-generating disc heat-conducting insulation material.