Patent Application
20120055918
The present disclosure relates to a heat-generating film and heat generating product comprising the same.
A planar heat-generator like a heat-generating film (or heat-generating sheet) can be applied to various uses such as a vehicle heat-generating sheet, stroller heat-generating sheet or portable heat-generating products.
A representative use to which the planar heat-generator is applied is a vehicle heat-generating sheet. In order to apply the planar heat-generator to the vehicle heat-generating sheet, the heat-generator should be capable of operating at a low voltage or low power with respect to the energy efficiency, and should have a good flexibility. Further, when the seat is occupied, the heat-generator should fit to a body curve of a sitter (hereinafter, sometimes depicted as ┌filling property)), be easily bent 3-dimensionally, and exhibit a soft buffer action so as to feel comfort (hereinafter, sometimes depicted as ┌comfort property)).
As the said heat-generating film or heat-generating sheet, a product wherein both sides of a wire-shape heat-generating material are wrapped with a non-woven fabric has been in use.
However, in case of the existing heat-generating product which has non-woven fabric attached to the both sides of the heat-generating material, there is a problem that higher output power should be provided due to the heat loss caused by insulation. Further, in the wire type product, the wire length should be elongated, and the wires of a back plate and cushion should be connected to direct current to offer higher resistance. If disconnection or shortage of the wire occurs at any part of the product having a direct current structure, product defects may be caused.
In order to complement these defects of the wire product, there is a known product which uses a carbon-coated wire as the heat-generating material. However, the carbon can't be uniformly coated on the said product, and therefore can't solve the regional heat generating problem.
Further, in case of a planar heat-generator using carbon, when it is applied to the vehicle sheet, the comfort property and filling property are not sufficient because it is not easy to bend the film and is difficult to reduce the thickness. Further, if carbon is used as the heat-generating material, large resistance change is generated by physical impacts such as continuous bending. Further, in case of a carbon material, an amount of the material should increase to convert kinetic energy of electrons to heat energy, and therefore low voltage heat-generation is not possible.
The present disclosure provides a heat-generating film and heat-generating product comprising the same.
According to one embodiment of the present disclosure, provided is a heat-generating film comprising: a base sheet; a heat-generating layer which is formed on the base sheet and has one or more heat-generating parts patterned in a linear configuration; and an electrode layer comprising a first main electrode and a second electrode which are patterned on the base sheet in a linear configuration perpendicular to the heat-generating part having the linear configuration and formed at both ends of the base sheet respectively, and one or more auxiliary electrodes which are extended from the first and second main electrodes in a direction parallel with the heat-generating part.
According to another embodiment of the present disclosure, provided is a heat-generating product comprising the heat-generating film according to the present invention; and a voltage application apparatus which can apply voltage to the electrode layer of the heat-generating film.
The present invention relates to a heat-generating film comprising: a base sheet; a heat-generating layer which is formed on the base sheet and has one or more heat-generating parts patterned in a linear configuration; and an electrode layer comprising a first main electrode and a second electrode which are patterned on the base sheet in a linear configuration perpendicular to the heat-generating part having the linear configuration and formed at the both ends of the base sheet respectively, and one or more auxiliary electrodes which are extended from the first and second main electrodes in a direction parallel with the heat-generating part.
Hereinafter, the heat-generating film according to the present invention will be described in detail.
As shown in the attached
Hereinafter, the expression such as ┌B formed at the upper (or lower) of A┘ or ┌B formed on A┘, is used as a reference including a case that B is directly attached to the upper or lower part of A; a case that B is attached to the upper or lower part of A via an adhesive layer or pressure sensitive adhesive layer; and a case that one or more layers are formed at an upper or lower part of A, and B is attached to the layers directly or via the adhesive layer or pressure sensitive adhesive layer.
The kind of the base sheet (11) which can be used to prepare the heat-generating film (1) of the present invention is not particularly limited, and, for example, a general synthetic resin film known in the art can be used.
The example of the synthetic resin may be one or more laminated films selected from polyester film (ex. PET film), polyurethane film, polymethylmethacrylate film, polyvinyl chloride film, polyethylene film, polypropylene film, polyvinylidene fluoride (PVDF) film and ABS (Acrylate-Butadiene-Styrene copolymer) film.
In the present invention, in the point of view of the comfort property and filling property of the heat-generating film, the polyester film (preferably biaxially oriented polyester film (ex. BOPET (biaxially oriented polyethylene terephthalate) film)); or the laminated film of the polyester film and polyurethane film (preferably thermoplastic polyurethane film (TPU (thermoplastic polyurethane) film)) can be used as the base sheet, but not limited thereto.
In the present invention, a thickness of the base sheet may be in a range of 50 μm to 300 μm, preferably from 100 μm to 200 μm, and more preferably from 100 μm to 150 μl. If the thickness of the base sheet of the present invention is less than 50 μm, the overall stability of the heat-generating film may decrease. Further, if the thickness of the base sheet of the present invention exceeds 300 μm, physical properties such as comfort property and filling property may decrease.
However, the thickness of the base sheet is nothing but an example of the present invention. Namely, in the present invention, the thickness of the base sheet can be controlled properly in consideration of the kind of the base sheet, a structure thereof taking into consideration whether it is a monolayer or multilayer, a laminated structure, and the desired comfort property and filling property.
For example, if the said polyester film (ex. biaxially oriented polyester film) as a base sheet is used in the present invention, the thickness thereof may be set to 110 μm or less, and preferably about 100 μm in the consideration of the desired comfort property and filling property. Further, if the said laminated film of the polyester film (ex. biaxially oriented polyester film) and polyurethane film (ex. thermoplastic polyurethane film) as the base sheet is used in the present invention, the thickness of the polyester film can be set to about 60 μm or less, and preferably about 50 μm, and the thickness of the polyurethane film can be set within a range of about 50 μm to 100 μm in the consideration of the desired physical properties.
The heat-generating film (1) of the present invention comprises the heat-generating layer (12) formed at the upper part of the base film (11).
As shown in
In the present invention, it is preferred that the heat-generating part (12a, 12b, 12c and the like) included in the heat-generating layer is patterned to a configuration having a prescribed rule on the base sheet in relation to low voltage driving quality.
Specifically, in the heat-generating film of the present invention, the width (W of
In the present invention, in relation to low voltage driving quality of the heat-generating film and uniform heat-generating induction, the width (W) and distance (P) of the heat-generating part are proportional each other. Namely, in case that the width (W) of the heat-generating part is set relatively short in the present invention, if the distance of the heat-generating part is too far, the low voltage driving quality may decrease, or inducing uniform heat-generation in the heat-generating film may be difficult. On the other hand, in case that the width (W) of the heat-generating part is set relatively long in the present invention, if the distance of the heat-generating part is too close, the low voltage driving quality may decrease, or inducing uniform heat-generation in the heat-generating film may be difficult. Thus, in the present invention, it is preferred that the dimension of the heat-generating part is set in the consideration of the said proportion relation. For example, if the width of the heat-generating part is set to about 8 mm in the present invention, the distance (P) of the heat-generating part can be adjusted to 10 mm to 12 mm, and preferably about 10 mm; if the width (W) of the heat-generating part is set to about 9 mm, the distance (P) of the heat-generating part can be adjusted to about 10 mm to 14 mm, and preferably about 12 mm; and if the width (W) of the heat-generating part is set to about 10 mm, the distance (P) of the heat-generating part can be adjusted to about 13 mm to 15 mm, and preferably about 15 mm. However, the said example is only one embodiment of the present invention, and the dimension of the said pattern can be controlled in the present invention as long as low voltage driving quality and uniform heat-generating induction are obtained.
Further, in the heat-generating film of the present invention, a thickness of the heat-generating part may be in a range of about 1 μm to 10 μm, and preferably about 3 μm to 7 μm. If the thickness of the heat-generating part is too low in the present invention, the heat-generating efficiency may decrease. On the other hand, if the part is too thick, the mass-producibility of the heat-generating product may decrease, or the product characteristics such as the comfort property and filling property may go down.
On the other hand, a length (L of
In the present invention, a material which makes up the said heat-generating part or the heat-generating layer comprising the heat-generating part is not particularly limited. For example, the heat-generating part may include carbon nanotubes (CNTs) as the heat-generating material. Accordingly, when the CNTs are used as the heat-generating material, in comparison with the existing carbon material, problems that the heat-generating material is separated by a physical impact in use and that the resistance is changed severely can be solved, and low voltage operation can be more efficient because the amount of the heat-generating material to convert the kinetic energy of the electrons to heat energy can be small.
More specifically, the heat-generating part may comprise a binder resin and CNTs in the present invention, and the CNTs may be contained in an amount of about 3 weight parts to 15 weight parts based on the 100 weight parts of the binder resin. If the amount of the CNTs is less than 3 weight parts in the present invention, the low voltage driving quality of the heat-generating film may decrease, or the heat-generating efficiency may go down. Further, if the amount of CNTs exceeds 15 weight parts, the mass-producibility of the product or economic efficiency may decrease.
The kind of the binder resin which can be used is not particularly limited, and any resin which is conventionally used as a binder can be used. For example, acryl resin (ex. EXP-6, LG chemistry), polyester resin (EPON 828, Natrochem), PVC resin (KA-SP-2, KSA), PVAc resin (Elotex W product, National Starch) or EVA resin (Flowkit FL product, National Starch) can be used.
Further, the kinds of CNTs which can be used in the present invention are also not particularly limited, and, for example, Multi-walled CNTs (MWCNTs) can be used. CNTs have a structure wherein a graphene sheet is rolled with a nano-size diameter, and can be classified into Single-walled CNTs (SWCNTs), Double-walled CNTs (DWCNTs) and Multi-walled CNTs (MWCNTs) according to the number of layers overlapped by the rolling of the graphene sheets. In the present invention, it is preferred to use MWCNTs among the said CNTs, but not limited thereto. In the present invention, for example, carbon nanotubes having a cross section diameter of about 4 nm to 15 nm and aspect ratio of 1,200 to 20,000 can be used.
In the present invention, a method to constitute the heat-generating part comprising the said components is not particularly limited. In the present invention, for example, first of all, the binder resin and carbon nanotubes described above are dispersed in the proper solvent (ex. Ketone-based solvent such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) or acetone; alcohol-based solvent such as isopropyl alcohol (IPA) or n-hexanol; 1,2-dichlorobenzene, N-methylpyrrolidone (NMP) or N,N-dimethylformamide (DMF)), and diluted to the proper concentration to prepare a coating solution. Then, the coating solution is applied by a gravure printing or silk printing method to obtain the heat-generating part or heat-generating layer.
On the other hand, in the present invention, a punching hole (11a, 11b, 11c and the like) can be formed on the base sheet (11) between each heat-generating part (12a, 12b, 12c and the like) which is patterned in a linear configuration as shown in
The heat-generating film (1) of the present invention comprises an electrode layer (13) formed at the upper part of the heat-generating layer (12).
In the present invention, as shown in
In the present invention, it is preferred to set a two point resistance of the main electrode (13a, 13b) to about 0.4 Ω/cm or less, preferably 0.2 Ω/cm or less, and to set the two point resistance of the auxiliary electrode (13c, 13d) to within a range of 0.4 Ω/cm to 0.7 Ω/cm. The term ┌two point resistance┘ used in the present invention refers to a resistance measured between two points with a random distance using a known two point resistor. The present invention can prevent inducing unnecessary heat-generation at the electrode layer, and control to induce uniform heat-generation all over the heat-generating film by setting the two point resistances of the main electrode and auxiliary electrode to the range described above. On the other hand, in the present invention, the operation is more efficient as the two point resistance of the main electrode (13a, 13b) is lower, and the lower limit is not particularly limited.
On the other hand, in the present invention, it is preferred to pattern the electrode layer into a designated configuration in the point of view of inducing low voltage driving quality and uniform heat-generation like the heat-generating layer.
Namely, in the present invention, a width (W1) of the main electrode (13a, 13b) can be set to a range of about 8 mm to 30 mm, preferably from 8 mm to 12 mm, and more preferably from 9 mm to 11 mm. In the present invention, if the width (W1) of the main electrode (13a, 13b) is less than 8 mm, unnecessary heat-generation may be induced at the electrode part by over increasing the two point resistance of the main electrode, and if the width exceeds 30 mm, a resistance deviation may occur by the occurrence of a thickness deviation of the electrode layer.
Further, in the present invention, a thickness of the main electrode (13a, 13b) can be set to a range of about 5 μm to 25 μm, and preferably from 6 μm to 10 μm. In the present invention, the thickness of the main electrode (13a, 13b) is less than 5 μm, unnecessary heat-generation may be induced at the electrode part by over increasing the two point resistance of the main electrode, and if the thickness exceeds 25 μm, it may cause cracks and a resistance deviation at the cracked regions by the occurrence of a thickness deviation of the electrode layer when it is applied to a product requiring a flexibility.
On the other hand, in the present invention, the auxiliary electrode (13c, 13d) extended from the main electrode (13a, 13b) can also be formed into a designated pattern. For example, in the present invention, a distance (L1) between the plural auxiliary electrodes extended from one main electrode (ex. The first or second main electrode) can be in a range of about 5 mm to 30 mm, and preferably from about 16 mm to 26 mm.
Further, in the present invention, it is preferred to closely arrange the auxiliary electrode (13d) extended from the first main electrode (13a) and the auxiliary electrode (13c) extended from the second main electrode (13b) with a fixed distance (L2 of
Further, in the present invention, it is preferred to separately arrange the auxiliary electrode and the opposing main electrode thereto, namely, the main electrode which is across from the main electrode where the auxiliary electrode is extended from (for example, in
In the present invention, further, a width (W2) of the auxiliary electrode may be 0.5 mm or more, preferably 1 mm and more. If the width (W2) of the auxiliary electrode is less than 0.5 mm which is within the margins of error of electrode printing, the fluidity of the electric current may be changed or the heat-generating efficiency may decrease by the occurrence of non-uniform printing. On the other hand, in the present invention, the upper limit of the width (W2) is not particularly limited, and, for example, it can be controlled properly to be within a range of 3 mm or less.
As shown in
In the present invention, further, the first or second main electrode can have a double arrangement structure.
For a specific example, in the present invention, as shown in
In the above, widths of the first vertical part (13a1), the second vertical part (13a2) and the horizontal part (13a3), for example, can be controlled by the same method used for the main electrode of the heat-generating film. Namely, in the present invention, each width of the first vertical part (13a1), the second vertical part (13a2) and the horizontal part (13a3) can be 8 mm to 30 mm, respectively, or the width of the entire part which includes the first vertical part (13a1) and the second vertical part (13a2) (i.e., the width of the first vertical part+the width of the second vertical part+the distance between the first and second vertical parts) can be selected from a range of 8 mm to 30 mm. Further, the separation distance between the first vertical part (13a1) and the second vertical part (13a2) is not particularly limited, and, for example, can be selected properly in the consideration of the heat-generating efficiency of the heat-generating film. In the present invention, for example, the distance between the first vertical part (13a1) and the second vertical part (13a2) can be controlled properly to be within a range of 10 mm to 15 mm. Further, in the electrode pattern shown in
In the present invention, the electrode layer, specifically, any one of the main electrodes is constituted in a double arrangement like above to obtain an effect that the voltage is applied in the diagonal direction even when the voltage application apparatus is connected to the same direction in the two main electrodes. Thus, uniform heat-generation can be induced all over the heat-generating film even when the resistance exists at the electrode layer.
These effects will be described in detail as follows by referring to the attached FIGS.
The attached
In this way, because each material (ex. silver) making up the main electrode and auxiliary electrode also has a self resistance of a certain range, for example, energy from electrons moving to the upper part along the (+) voltage applied main electrode, the energy from the electrons moving to the lower part along the (−) voltage applied main electrode and the energy from the electrons moving in the parallel direction along the auxiliary electrode is converted to heat energy while moving through the resistance, and then dissipates. Therefore, in the constitution shown in
As a method to minimize the said problems, a method to intercross the directions of the applied voltage, wherein the electrons move diagonally by applying (+) voltage to the lower part of one main electrode and (−) voltage to the upper part of the other main electrode can be considered. However, the said method for applying the voltage may be impossible according to the application of the heat-generating film. For example, when the heat-generating film of the present invention is applied to the vehicle sheet, in the scheme of the product, the direction of the applied voltage is limited to one direction as shown in
However, if the electrode is constituted like the present invention, the voltage can be applied in a diagonal direction although the direction of the applied voltage is limited. Accordingly, uniform heat-generation can be induced all over the heat-generating film without any loss of the energy of the electrons caused by the self resistance of the electrode.
For example, as shown in
In the present invention, a material making up the said electrode layer is not particularly limited. For example, the electrode layer of the present invention may be a silver (Ag) electrode layer.
Further, in the present invention, a method for constituting the said silver electrode layer is not particularly limited. For example, first of all, conventional silver nanoparticles used for preparing the electrode are dispersed in a proper solvent (ex. Ketone-based solvent such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) or acetone; alcohol-based solvent such as isopropyl alcohol (IPA) or n-hexanol; 1,2-dichlorobenzene, N-methylpyrrolidone (NMP) or N,N-dimethylformamide (DMF)), and diluted to the proper concentration to prepare a coating solution (concentration of the silver nanoparticles is about 55 weight % to 72 weight %). Then, the coating solution is applied by a gravure printing or silk printing method to obtain the electrode layer.
In addition, the heat-generating film of the present invention may further comprise a protection layer (14) formed at the upper part of the electrode layer (13) as shown in
In the present invention, a material making up the said protection layer (14) is not particularly limited, and, for example, the protection layer (14) may comprise a synthetic resin film; and an adhesive layer formed on one or both sides of the synthetic resin film. In the above, the kind of the synthetic resin film which can be used is not particularly limited, and, for example, the same film with the synthetic resin film making up the base sheet described above, preferably a biaxially oriented polyester film can be used, but not limited thereto.
Further, the kind of the adhesive layer which is formed on one or both sides of the synthetic resin film is not particularly limited, and a conventional acryl-based adhesive, EVA-based adhesive or polyvinyl alcohol-based adhesive can be used.
Further, a thickness of the protection layer (14) can be selected properly in the consideration to the application, and, for example, the thickness of the synthetic resin film can be set to about 20 μm to 30 μm, preferably about 25 μm, and the thickness of the adhesive layer can be set to about 20 μm to 80 μm, about 25 μm to 75 μm, or about 25 μm to 50 μm, but not limited thereto.
In addition, the heat-generating film of the present invention may further comprise a surface layer formed at the upper part of the electrode layer. This surface layer may be formed at the upper part of the said protection layer (14) as shown in attached
In the present invention, the kind of the surface layer is not particularly limited, and, for example, general woven fabric or non-woven fabric, preferably woven fabric can be used.
In the present invention, examples of the woven fabric or non-woven fabric may include a woven fabric or non-woven fabric which is prepared with one or more synthetic resin fibers selected from a polyester fiber, polyamide fiber, polyurethane fiber, acryl fiber, polyolefin fiber or cellulose fiber; woven fabric or non-woven fabric which is prepared with a cotton (ex. A thread prepared with cotton cloth); or woven fabric or non-woven fabric which is prepared by mixing the synthetic resin fiber and cotton. It is preferred to use polyester fiber; or woven fabric prepared with the polyester fiber and cotton among the said examples in the present invention, but not limited thereto. Further, a method of preparing the woven fabric or non-woven fabric using the said materials is not particularly limited, and, for example, the fabric can be prepared by a general paper-making or weaving process.
In the present invention, a thickness of the said surface layer may be in a range of 200 μm to 2,000 μm. If the thickness of the surface layer is less than 200 μm in the present invention, the reinforcement effect such as the configuration stability by forming the surface layer may be slight, and if the thickness exceeds 2,000 μm, the characteristics of the heat-generating film such as the comfort property or filling property may decrease.
In addition, the heat-generating film of the present invention may further comprise an inside layer (16) which is formed at the lower part of the base sheet (11) as shown in attached
Further, the present invention relates to a heat-generating product comprising the heat-generating film described above; and a voltage application apparatus which can apply the voltage to the heat-generating film.
This heat-generating product of the present invention may be, for example, a vehicle heat-generating sheet, stroller heat-generating sheet, portable cushion, portable mat, clothing (ex. jumper, coat, parka and the like), portable chair or portable bed and the like.
As described above, the heat-generating film according to the present invention can generate heat continuously and stably even at a low voltage, for example, about 12 V, and exhibits good comfort and filling property by having excellent flexibility, as well as various properties such as fire retardancy and corrosion resistance. Therefore, the heat-generating film of the present invention can be applied to the various heat-generating products as described above and can exhibit excellent effects.
While using the heat-generating film according to the present invention, other constitutions of the said heat-generating product of the present invention, for example, the voltage application apparatus, main body of the vehicle sheet and method for constructing the sheet are not particularly limited, and the conventional materials and method which are known in the art can be applied without limitation.
Hereinafter, the following examples are provided to further illustrate the invention, but they should not be considered as the limit of the invention.
100 weight parts of an acryl resin (EXP-6, LG chemistry) and about 10 weight parts of MWCNT (EXA E&C Inc.) were dispersed in a solvent (isopropyl alcohol) to prepare a coating solution for forming a heat-generating part. Then, the prepared coating solution was applied by a gravure printing method to form a patterned heat-generating part on a biaxially oriented polyester film (BOPET) having a thickness of 100 μm, horizontal length of 800 mm and vertical length of 600 mm as shown in
The procedure of Example 1 was repeated except for setting the width (W) to 9 mm and distance (D) to 10 mm when the pattern of the heat-generating part was formed to prepare the heat-generating film.
The procedure of Example 1 was repeated except for setting the width (W) to 9 mm and distance (D) to 12.5 mm when the pattern of the heat-generating part was formed to prepare the heat-generating film.
The procedure of Example 1 was repeated except for setting the width (W) to 10 mm and distance (D) to 12.5 mm when the pattern of the heat-generating part was formed to prepare the heat-generating film.
The procedure of Example 1 was repeated except for setting the width (W) to 10 mm and distance (D) to 15 mm when the pattern of the heat-generating part was formed to prepare the heat-generating film.
As a planar heat-generator, the existing wire type product used generally was prepared and used as a Comparative Example. Specifically, it was a heat-generating product (27 Watt (DC12 Volt) (88190-2H100, Kwangjin Wintec) prepared by attaching Ni—Cr wire which has a thickness of 1 mm to a cross section of a non-woven fabric (100 g) which has a horizontal length of 800 mm and vertical length of 600 mm with a gap of 30 mm by using a hot-melt adhesive.
A 12V voltage was applied to the heat-generating film of Example 1 and Comparative Example 1, and whether heat was generated uniformly all over the film was observed through an infrared camera (IR Flexcam Pro, Infrared Solution), then the result was shown in
The heat-generating film of the present invention can continuously and stably generate heat even at a low voltage, for example, at a voltage of 12V or lower. In addition, the heat-generating film of the present invention has excellent comfort properties, filling properties and flexibility. Accordingly, the heat-generating film of the present invention can be applied to a variety of heat-generating products, for example a heat-generating sheet for a vehicle or baby stroller, or to a variety of portable heat-generating products and the like, and exhibits superior effects.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the novel methods and apparatuses described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2009-0100452 | Oct 2009 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR10/07005 | 10/13/2010 | WO | 00 | 11/10/2011 |
