KR100770442B1 - Softness heating sheet - Google Patents

Abstract

A flexible heating sheet is provided to improve a flexibility property of the heating sheet by completely attaching a synthetic resin to a conductive carbon black and a silver paste. A flexible heating sheet is made of a laminate. The laminate includes a lower insulation layer, a heating layer, and an upper insulation layer. The lower insulation layer is made of a PET(PolyEthyleneTerephthalate) nonwoven fabric layer(11). The heating layer includes a conductive carbon black layer(13) and a silver paste layer(14). The upper insulation layer is made of a second linear low-density polyethylene film layer(12b). The lower insulation layer is attached to the heating layer by using a first linear low-density polyethylene film layer(12a).

Description

Softness heating sheet

1 is a cross-sectional view of a conventional heating sheet.

2 is a cross-sectional view of another conventional heating sheet.

3 is a cross-sectional view of the flexible heating sheet of the embodiment according to the present invention.

Figure 4 relates to a cross-sectional view of a flexible heating sheet of another embodiment according to the present invention.

5 is a cross-sectional view illustrating a state in which the flexible heating sheet of FIG. 4 is laminated.

Figure 6 relates to a cross-sectional view of a flexible heating sheet as another embodiment according to the present invention.

7 is a view showing a state of use of the flexible heating sheet according to the present invention.

Explanation of symbols on the main parts of the drawings

10: heat generating sheet 11: polyethylene terephthalate nonwoven fabric layer

12: linear low density polyethylene film layer 13: conductive carbon black layer

14 silver paste layer 15 shielding layer

16: outer insulation layer

The present invention relates to a flexible heating sheet, and more specifically, by using a conductive carbon black and silver paste completely bonded to a synthetic resin non-woven fabric and a strong adhesive strength, because the copper wire is not arranged inside the heating sheet is excellent in flexibility The present invention relates to a flexible heating sheet, which can be applied to daily household goods such as mats, duvets, cushions, and vests.

In general, the heating sheet is prepared by installing an electrode at both ends on a heating element of a thin carbon layer and insulating coating with a heat resistant polymer film, which is called a planar heating element. The heat generating sheet can maximize heat efficiency by dissipating even heat from the whole sheet. Also, even if the film is partially damaged due to the nature of the heat generating sheet, the heat generating sheet can be used semi-permanently because it does not interfere at all. It is widely used as daily necessities such as bed mats, duvets, cushions, and vests.

As described above, in the case of a heating sheet used in household goods such as bed mats, duvets, cushions, and vests, the polyethylene terephthalate film layer 2 from the bottom as shown in FIG. ) And a structure in which a copper wire 3 and a polyethylene terephthalate film layer 2 on which conductive carbon black 5 is printed are laminated on top of each other, and a heating sheet is embedded in a product such as an electric blanket or an electric blanket. Since the flexibility of the heat generating sheet is reduced by the copper wires 3 arranged at a predetermined interval inside the heat generating sheet, there are problems such as an inconvenience in handling or storing the heat generating sheet.

On the other hand, in the case of the heating sheet used for the purpose other than the household goods or medical supplies, as shown in FIG. 2, two copper thin plates 1 having a predetermined thickness and width are coated with a conductive adhesive coating on one side thereof. To maintain an appropriate interval on the lower surface of the insulating film (2) to bond; Applying a silver liquid phase (3) onto the copper foil (1) attached to the lower surface of the insulating film (2) and drying for a predetermined time; The carbon liquid phase 7 is coated on the dried silver part 3 and dried to cover the entire surface of the copper foil 1, the silver part 3, and the carbon heating element 7 with the upper surface of the insulating film 9. And it is known that the heating sheet, characterized in that the waterproof treatment, but the heating sheet is not flexible due to the copper wire arranged therein still could not solve the above problems.

Therefore, the present invention is a solution to the above problems, by fully bonding the conductive non-woven fabric and a strong adhesive strength using a conductive carbon black and silver paste, it is excellent in flexibility because it does not arrange the copper wire inside the heating sheet It is an object of the present invention to provide a flexible heating sheet, which is characterized in that it is easy to handle and store so that it can be used in the interior of daily living products such as bed mats, duvets, cushions and vests.

Referring to the configuration of the flexible heating sheet of the present invention for solving the above problems in detail with reference to the accompanying drawings as follows.

3 is a cross-sectional view of the flexible heating sheet according to the present invention.

In the flexible heating sheet 10 made of a laminate,

The laminate is a lower insulating layer consisting of a polyethylene terephthalate nonwoven layer 11,

A heat generating layer consisting of the conductive carbon black layer 13 and the silver paste layer 14 and

An upper insulating layer composed of a linear low density polyethylene film layer 12b,

The lower insulating layer and the heat generating layer is characterized in that the adhesion to the linear low density polyethylene film layer (12a).

In the heat generating sheet 10 of the present invention, as shown in FIG. 4, the shielding layer 15 may be stacked on the upper insulating layer. The shielding layer 15 absorbs the induced current generated from the heating sheet. It is preferable to use the laminated body laminated | stacked in the order of the linear low density film layer, the polyethylene telephthalate film layer, and the conductive carbon black layer from the top as a shielding layer.

In the present invention, the linear low density polyethylene film layer and the polyethylene terephthalate nonwoven layer are layers that serve to insulate and bond the respective layers, and the width of the layers is wider than that of the heat generating layer, thereby generating heat as shown in FIG. 5. The layers are laminated in a mutually wrapped form to form an insulating layer to be insulated and waterproof so that the insulation and waterproof functions are improved.

The synthetic resin used in the linear low density polyethylene film layer of the present invention may be selected from polypropylene resin or ethylene vinyl acetate resin in addition to the linear low density polyethylene resin.

In addition, in the present invention, the upper and lower insulating layers of the heating sheet serve as a waterproof layer, but in order to further increase the insulation, the polyvinyl chloride resin or the polyurethane resin is again used outside the upper and lower insulating layers as shown in FIG. 6. By forming the outer insulating layer 16 by laminating, it is possible to more fully improve the insulation and waterproof properties to prevent safety accidents due to short circuits.

And the coating liquid for forming the conductive carbon black layer 13 of the present invention is composed of 20-30% by weight of the main material, which is a mixture of conductive carbon black and synthetic resin, and 70-80% by weight of the solvent. And it is preferable that the mixture of the conductive carbon black and synthetic resin which are the subjects consists of 35-45 weight% of carbon black, and 55-65 weight% of synthetic resins. The conductive carbon black layer 13 may be completely adhered to the silver paste layer 14 when the blending amount of carbon black is less than 35 wt% or the blending amount of synthetic resin is more than 65 wt%. When the amount of carbon black is reduced, the exothermic effect may be lowered, and when the amount of carbon black exceeds 45% by weight or the amount of the synthetic resin is less than 55% by weight, the exothermic effect is good but the amount of synthetic resin is lowered. As a result, the adhesion between the conductive carbon black layer 13 and the silver paste layer 14 may be weakened.

In addition, if the mixing amount of the main body is less than 20% by weight, or the content of the solvent exceeds 80% by weight, the viscosity of the conductive carbon black coating liquid is too low, there is a fear that the gravure printing does not print properly, and the mixing amount of the main body 30 If the content is more than the weight% or the content of the solvent is less than 70 weight%, the viscosity of the conductive carbon black coating liquid may be too high, which may lower workability during gravure printing.

The synthetic resin used in the conductive carbon black coating solution is preferably selected from one of a polyurethane resin and an epoxy resin, but is not necessarily limited to the synthetic resins listed above.

In the present invention, the solvent used for the conductive carbon black coating solution is preferably selected from one of methyl ethyl ketone (MEK), ethyl acetate (EA), isopropyl alcohol (IPA).

In addition, the coating liquid for forming the silver paste layer 14 of the present invention is composed of 20-30% by weight of the main material and a solvent 70-80% by weight of a mixture of silver paste and synthetic resin. And the mixture of the main silver paste and the synthetic resin is preferably made of 35 to 45% by weight silver paste, 55 to 65% by weight synthetic resin. In the above subject matter, when the amount of the silver paste is less than 35% by weight or the amount of the synthetic resin is more than 65% by weight, the conductive carbon black layer 13 may be completely adhered to the silver paste layer 14, but relatively If the amount of silver paste mixed decreases, the exothermic effect may decrease, and when the amount of silver paste exceeds 45% by weight or the amount of synthetic resin is less than 55% by weight, the exothermic effect is good but the amount of synthetic resin decreases. As a result, the adhesion between the conductive carbon black layer 13 and the silver paste layer 14 may be weakened.

In addition, if the mixing amount of the main material is less than 20% by weight or the content of the solvent exceeds 80% by weight, the viscosity of the silver paste coating liquid may be too low to coat properly, and the mixing amount of the main material exceeds 30% by weight In the case where the solvent content is less than 70% by weight, the viscosity of the silver paste coating liquid may be too high, thereby decreasing the coating workability.

The synthetic resin used in the silver paste coating liquid is preferably selected from one of polyurethane resin and epoxy resin, but is not necessarily limited to the synthetic resins listed above.

The metal used for the silver paste layer of the present invention is not necessarily limited to silver, and may be used by selecting one of copper, nickel, and graphite having excellent conductivity, and then using it as an ink. However, the conductivity is limited to that of carbon black.

Looking at each layer of the laminate constituting the upper insulating layer, the polyethylene terephthalate nonwoven layer 11 serves to improve the physical strength by acting as a support for the heating sheet laminate with an insulating effect, linear low density polyethylene film Layer 12 serves to exhibit waterproofing and insulating effects. In addition, the material used for the polyethylene terephthalate nonwoven fabric layer 11 is not necessarily limited to the polyethylene terephthalate nonwoven fabric, and may be selected from one of cotton woven fabric and craft paper.

And in order to prevent the thickness of the heat generating sheet of the present invention in consideration of the flexibility in handling and construction is not too thick, the thickness of each laminate layer is preferably adjusted to 30 ~ 150 ㎛.

For reference, Figure 7 shows a state of use of the flexible heating sheet as an embodiment according to the present invention, it shows a state in which the flexible heating sheet 10 is embedded in the interior of the electric mat (20).

Hereinafter, the configuration of the present invention in detail through the following examples.

(Example)

1. Preparation of Test Piece

As shown in FIG. 3, a flexible heating sheet having a structure having a thickness of 50 to 100 μm (wherein, the thickness of the linear low density polyethylene film layer 12 is 100 ± 10 μm) was prepared as shown in Table 1 below. The amount of coating of the conductive carbon black and the silver paste coating liquid was adjusted as described in the above] to obtain the samples of Examples 1 to 3.

And as a comparative sample in contrast to the present embodiment, as a laminate having a structure as shown in Figure 1, the thickness of each laminate is 50 ~ 100㎛ (where the thickness of the linear low density polyethylene film layer is 100 ± 10㎛) A heat generating sheet having a phosphorus structure was prepared, but the coating amount of the conductive carbon black coating solution was adjusted to the samples of Comparative Examples 1 to 3 as shown in Table 1 below on the copper wire 3.

TABLE 1

                                                       (Unit: μm)

division Example Comparative example One 2 3 One 2 3 Conductive Carbon Black Layer ^{1 )} 30 50 100 30 50 100 Silver Paste Layer ^{2 )} 30 50 100 - - -

Note 1) Conductive carbon black coating liquid is carbon black 10% by weight, polyurethane 20% by weight, MEK 70% by weight.

    2) Silver paste coating solution is 10% by weight silver paste, 20% by weight polyurethane, 70% by weight MEK.

2. Electrical safety test

The results of testing the withstand voltage and insulation resistance for 1 minute using the withstand voltage tester at a voltage of 2,000V are shown in [Table 2].

TABLE 2

division Example Comparative example One 2 3 One 2 3 Withstand voltage ^{2 )} pass pass pass pass pass pass Insulation resistance ^{3 )} pass pass pass pass pass pass

Note 2) and 3) Withstand 1500V.

3. Flexibility test

Samples of the Examples and Comparative Examples were folded and repeated, and the results of the flexibility test by visual and tactile judgment were repeated as shown in Table 3 below.

TABLE 3

division Example Comparative example One 2 3 One 2 3 Flexibility ^{3 )} ○ ○ ○ △ △ ×

Note 3) Flexibility Judgment

    -○ is good when observing the bending state and heat state of the heating sheet.

    -When △ is normal by observing the bending state and heat state of the heating sheet

    -× indicates defects by observing the bending and stiffness of the heating sheet.

As a result of testing the samples through the above experiments, as shown in [Table 2], the samples of Examples and Comparative Examples passed both the withstand voltage and insulation resistance in the electrical stability test, but in the flexibility test, as shown in [Table 3] In the case of all the flexibility was good, but in the case of the comparative example has a copper wire is built in the heat sheet is less flexible than the embodiment, the performance of the flexibility was shown to be normal or poor.

Therefore, it was found that the heat generating sheet of the present invention had excellent flexibility performance compared to the heat generating sheet of the comparative example in which the copper wires were not built up without the copper wires arranged in the laminate.

The flexible heating sheet according to the present invention has been sufficiently confirmed as to excellent performance of the flexibility as described in detail through the above embodiment, the present invention is not necessarily limited only to the above embodiment, the above specific embodiment In addition to the examples, various modifications can be made by changing the material of the laminate.

The present invention having the above structure is completely bonded by using a conductive carbon black and silver paste to a synthetic resin nonwoven fabric and a strong adhesive resin, and does not arrange the copper wire inside the heating sheet, so it is excellent in flexibility and easy to handle and store the bed It is characterized in that it can be used in the interior of daily necessities such as mats, duvets, cushions and vests.

Claims (8)

In the flexible heating sheet consisting of a laminate, The laminate is a lower insulating layer consisting of a polyethylene terephthalate nonwoven layer, A heat generating layer comprising a conductive carbon black layer and a silver paste layer, An upper insulating layer composed of a linear low density polyethylene film layer, The shielding layer is formed on top of the upper insulating layer, The lower insulating layer and the heating layer are bonded to the linear low density polyethylene film layer, A flexible heating sheet, characterized in that the outer insulating layer was formed by laminating each of the upper and lower insulating layers again using polyvinyl chloride resin or polyurethane resin. The method of claim 1, The conductive carbon black layer is composed of 20-30% by weight of the main material, which is a mixture of conductive carbon black and synthetic resin, and 70-80% by weight of the solvent, And the mixture of the conductive carbon black and the synthetic resin, which is the main subject, is 35 to 45% by weight of carbon black and 55 to 65% by weight of the synthetic resin.        The method of claim 1, The silver paste layer is made of a mixture of silver paste and synthetic resin 20-30% by weight and a solvent 70-80% by weight, And the subject is a flexible heating sheet, characterized in that consisting of 35 ~ 45% by weight silver paste, 55 ~ 65% by weight synthetic resin. The method according to claim 2 or 3, The synthetic resin flexible heating sheet, characterized in that used by selecting one of the polyurethane resin, epoxy resin. The method according to claim 2 or 3, The solvent is a flexible heating sheet, characterized in that used to select one of methyl ethyl ketone (MEK), ethyl acetate (EA), isopropyl alcohol (IPA). delete delete delete

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