CN107809811B

CN107809811B - Metal-free heating element and heating pad

Info

Publication number: CN107809811B
Application number: CN201711135907.9A
Authority: CN
Inventors: 崔仁植; 金允国
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-11-16
Filing date: 2017-11-16
Publication date: 2020-12-15
Anticipated expiration: 2037-11-16
Also published as: CN107809811A

Abstract

The application relates to a metal-free heating element, belonging to the field of heating devices. The heating element comprises the following components: Multi-Walled carbon nanotubes ((Multi-Walled CNTs, MWCNTs), polylactic Acid (PLA), Polybutylene Terephthalate (PBT) and Polybutylene Adipate-co-Terephthalate (PBAT) the present application also provides a heating pad having the heating element, and use of the heating element.

Description

Metal-free heating element and heating pad

Technical Field

The application relates to a metal-free heating element and a heating pad, belonging to the field of heating devices.

Background

The heating element is often used in a heating pad, which is a heating appliance widely used in common families in winter. The heating pad generally uses a metal wire as a heating element to generate heat, and a household alternating current power supply is directly used. The metal wire is used as a heating element and directly uses the heating pad of alternating current, the energy efficiency is not high, and the risk of electric leakage can exist due to the direct use of the alternating current, and meanwhile, the electromagnetic radiation can also cause damage to a human body. Therefore, a demand for a heating pad using a heating element capable of improving energy efficiency, reducing electromagnetic radiation, and reducing a risk of electric leakage has been rising.

In order to meet the above requirements, various technologies using Carbon fibers or Carbon Nanotubes (CNTs) as heat generating elements have been developed.

For example, KR2002-0033509 discloses a heating element of a pulp and carbon fiber composite sheet including carbon fibers and bast fibers (the foreskin 32406 is maintained), and KR10-1455379 discloses a carbon nanotube photo-heating product including carbon nanotubes, a dispersant, a resin binder, and an ultraviolet and ultraviolet absorbing substance, and a bedding product manufactured by such a manufacturing method.

Furthermore, registered patent No. KR10-1543058 discloses a heat-generating film containing carbon nanotubes laminated and improved on the surface of an automobile battery having excellent electrical conductivity and dispersion, published patent No. KR10-2016-0026245 discloses a method for producing a heat-generating layer containing carbon nanotubes, and registered patent No. KR10-1488898 discloses a method for producing a carbon nanotube transparent heat-generating substrate containing carbon nanotubes, a binder, a solvent, a dispersant and a glass print.

Disclosure of Invention

An object of the present invention is to provide a metal-free heating element having a small heat capacity, which does not accumulate heat and which has a characteristic of releasing a large amount of heat to the outside. The technical scheme of the application is as follows:

one embodiment of the present application provides a metal-free heating element, which may be referred to as a heating element hereinafter, the heating element including: Multi-Walled carbon nanotubes ((Multi-Walled CNTs, MWCNTs), polylactic Acid (PLA), Polybutylene Terephthalate (PBT) and Polybutylene Adipate-co-Terephthalate (PBAT).

A second embodiment of the present application provides a heat generating pad, including: the metal-free heating elements are arranged in parallel in the heating pad; connecting wires connecting the metal-free heating elements arranged in parallel; a temperature sensor mounted inside the heating pad for sensing temperature and a temperature fuse for cutting off current; a temperature regulator connecting the connecting line, the temperature sensor and the temperature fuse; and an external adapter connected to the temperature regulator and converting the alternating current to direct current.

A third embodiment of the present application provides a use of a metal-free heating element in a heating pad.

Drawings

FIG. 1 is an internal view of a heat generating pad according to an embodiment;

FIG. 2 is an internal view of another embodiment of a heat generating pad;

FIG. 3 is a bonding diagram of a heating element and a connecting wire;

wherein: the heating device comprises a heating pad 10, a heating element 20, a temperature fuse 30, a temperature sensor 40, a temperature regulator 50, an adapter 60, a connecting wire 70, a first wire 71, a second wire 72, a heating wire 73 and a joint 80.

Detailed Description

The technical solutions of the present application are explained in detail below with reference to specific embodiments, however, it should be understood that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

In the description of the present application, it is noted that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The embodiments described above are merely preferred embodiments of the present application, and are not intended to limit the scope of the present application, and various modifications and improvements made to the technical solutions of the present application by those skilled in the art without departing from the spirit of the present application should fall within the protection scope defined by the claims of the present application.

Specifically, the PBAT is a copolymer of butylene adipate and butylene terephthalate, and has the characteristics of both PBA and PBT.

In a preferred embodiment, the heating element has the following components in the ratio: 12-15 wt% of MWCNT, 10-14 wt% of PLA, 61-73 wt% of PBT, and 5-10 wt% of PBAT.

As a preferred embodiment, the heating element may be obtained by mixing the above components together, followed by heating and extrusion molding in one step; or the composition can be obtained by mixing the components and placing the mixture into a preset mould to be heated and molded at one time.

In a preferred embodiment, the heating element is a heating wire extruded to have a diameter of about 3.5 to 4.0mm, or a heating sheet having a thickness of about 3.5 to 4.0 mm.

In a preferred embodiment, the thickness of the heating wire is 3.75mm, and the length of the heating wire is 1000 mm; when 12V direct current is applied to each heating wire, the current is 0.24A, and the temperature of each heating wire is about 45 ℃. When the heating mat having the heating element is covered up and down, the temperature may reach 55 to 60 c due to the greenhouse effect.

As shown in fig. 1 and 2, a second embodiment of the present application provides a heat generating pad 10 including:

the metal-free heating elements 20 are arranged in parallel in the heating pad 10, and the metal-free heating elements 20 are the heating elements described above;

a connection line 70 connecting the metal-free heating elements 20 arranged in parallel;

a temperature sensor 40 mounted inside the heating pad 10 for sensing temperature and a temperature fuse 30 for cutting off current;

a temperature regulator 50 connecting the connection line 70, the temperature sensor 40, and the temperature fuse 30;

and an external adaptor 60 connected to the temperature regulator 50 and converting the ac power into the dc power.

In a preferred embodiment, the heating pad 10 has a plurality of heating elements 20, the heating elements 20 are connected in parallel with each other through a connecting line 70, and the connecting line 70 for realizing the parallel connection may be the heating wire 73, or may be the first wire 71 directly; wherein the composition of the heating wire 73 is the same as or similar to that of the heating element 20.

As shown in fig. 1, the heating elements 20 are connected in parallel via the heating wire 73, and the heating wire 73 is connected to the first electric wire 71 and finally connected to the temperature regulator 50. Alternatively, as shown in fig. 2, the heating elements 20 are connected in parallel by a first wire 71, and the first wire 71 is finally connected to the temperature regulator 50. I.e. both connected to the temperature regulator by means of the first electric line 71.

In a preferred embodiment, the heating element 20 and the connecting wire 70 are connected by insert injection bonding. As shown in fig. 3, after the heating element 20 and the connecting wire 70 are connected, a joint portion 80 is integrally formed, i.e., the joint portion 80 is formed by injecting a fixing substance, such as an adhesive, into the joint portion.

In a preferred embodiment, the temperature sensor 40 and the temperature fuse 30 are connected to the temperature regulator 50 through a second wire 72.

The metal-free heating element of the present invention can be used for manufacturing heating pads, including but not limited to the following fields:

building internal and external decoration: floor and indoor heating, etc.;

an automobile: batteries, indoor, back-rest and chair, mirrors, etc.;

articles for daily use: a hand warmer, vest, pad, cushion, bed, coffee cup, etc.;

agriculture and animal husbandry: a dryer, house heating, animal house heating, and the like;

aquaculture: a fish farm;

icing areas: roads, parking lot chairs, etc.;

mountain climbing equipment and fishing equipment: heating lunch boxes, folding chairs, etc.;

electrical equipment: a toilet, a water purifier, a fan heater, a water heater, an electric cooker, an iron and the like;

thermoelectric elements, communication repeaters, robots, unmanned planes, military use, etc.;

baby products: strollers, bottle warmers, cushions, and the like;

a hair dressing product: cosmetic heat preservation cabinets, blow drying machines and the like.

Example 1: heating pad with heating element

Specifically, fig. 1 and 2 show an internal view of a heating mat 10 having a metal-free heating element, wherein metal-free heating elements 20 made of multi-walled carbon nanotubes (MWCNT), PLA, PBT and PBAT are arranged in parallel in the heating mat 10, and each heating element 20 is connected by a connecting wire 70, wherein the connecting wire 70 can be a heating wire 73 shown in fig. 1 or a first electric wire 71 shown in fig. 2; and in the case of the heating wire 73, is finally connected to the first electric wire 71.

The connection between the heating elements 20 and the connecting wires 70 connected in parallel constitutes an insertion injection joint 80 as shown in fig. 3.

In addition, it is preferable that 2 or more temperature sensors 40 are disposed between the heating elements 20 arranged in parallel in the heating pad 10, sense the temperature of the heating pad 10 in use, and one or more temperature fuses 30 are provided to cut off the current in case of overload.

The first wire 71 connecting the heating element 20 and the second wire 72 connecting the temperature sensor 40 and the temperature fuse 30 are both connected to a conventional temperature regulator 50, which temperature regulator 50 is connected to an energy source (not shown) via an external adapter 60.

After the heating element 20, the temperature fuse 30, the temperature sensor 40 and the like in the heating pad 10 are connected by wires, the upper surface of the heating element is wrapped by fabric, the lower surface of the heating element is covered by surface fabric and is sewn, and the formed heating pad 10 is manufactured.

When 12V direct current is applied to each heating wire, the current is 0.24A, and the temperature of the heating wire is about 45 ℃. When the upper and lower sides of the heating pad 10 in fig. 1 are covered, the temperature can reach 55 to 60 c due to the greenhouse effect. It can be understood that a certain difference may occur due to a difference in composition ratio or thickness of the heater.

The heating pad 10 of the present application receives a signal from the temperature sensor 40 and supplies or stops current according to a set temperature, and when the temperature is overheated, the temperature fuse 30 is activated to cut off the current, thereby preventing a fire risk due to overheating, converting 220V ac power received from a household outlet into dc power through the adaptor 60, and supplying the dc power to the heating element 20 through the temperature regulator 50 via a wire, without an electric shock hazard, and greatly improving the thermal efficiency.

Example 2: performance testing

The heating element 20 of this application the heating wire heat capacity little, do not gather the heat, have the outside thermal characteristic of release more than 90%, more soft warm than metal heating element, heat energy release volume is more, has the inside even heat conduction's of messenger's heating pad advantage.

The heating element can replace wires and heating elements of metal series (copper and aluminum), has the effects of reducing carbon dioxide and reducing energy consumption, and can be widely applied to IT household appliances, living goods, unmanned aerial vehicles, electric automobiles, military use, robots, sensors, industrial goods, residential heating and other fields.

Compared with metal, the Carbon Nano Tube (CNT) can shield and absorb electromagnetic waves, release far infrared rays, resist bacteria and corrosion, resist oxidation and have more excellent moisture resistance than a surface heating element. The use of CNT-based olefin polymers is a new generation of new materials with excellent cold resistance (-50 ℃), durability and chemical resistance (acidic and basic).

As a specific embodiment, the composition ratio of the heat-generating element of the present application may be the following weight percentages shown in table 1:

[ TABLE 1 ]

Proportioning the components of the metal-free heating element according to a table to respectively obtain four groups of mixed components; then the mixed components are heated and extruded or pulled to form heating wires or heating sheets, and the heating wires or the heating sheets can be used in the heating pad.

The physical properties of the heating element are shown in table 2 below.

[ TABLE 2 ]

Item	MWCNT composite material of the present application	PP material
			Shrinkage rate	5/1000％	18/1000％
Impact strength	52.2kg cm/cm	6.0kg cm/cm
			Tensile strength	94.7kg/cm²,50mm/min	302.6kg/cm²,50mm/min
Elongation percentage	41.8％	22％
			Specific gravity of	1.05	0.92
Surface resistance	0.25Ω/sq	-
			Volume resistance	0.004Ω/cm	-

As can be seen from the above table, the MWCNT composite material used in the present application is greatly superior to the general PP material in terms of physical properties.

Table 3 below shows a comparison of characteristics between the conventional surface heating element and the heating element of the present application, and it can be seen that the heating element of the present application is excellent in stability and economy.

[ TABLE 3 ]

Table 4 below shows the test results of the electromagnetic wave shielding properties of the heating element (group 2 in table 1) used in the present application, which is well suited for use in the heating pad.

[ TABLE 4 ]

Input frequency	Test method	Condition	Results
				1.5GH	ASTM D 4935	2.0t	50～70dB

Table 5 below shows the heat generation experimental results of the heat generating element used in the present application. The conditions were 20 ℃ at room temperature, and the heating element used was a single wire having a diameter of 3.75mm (group 2 in Table 1).

[ TABLE 5 ]

As shown in table 5, the heating element used in the present application has excellent energy efficiency and is most suitable for use as a heating pad.

In addition, the heating element's that this application was used heating wire has Positive Temperature Coefficient (PTC) for heating wire itself has the Temperature automatic control function, and the characteristic of generating heat risees when low Temperature (0 ~ 10 ℃) has overheated prevention and energy-conserving effect. When the temperature rises, the heating element expands, the contact points of the carbon nano tubes are separated, the conductivity can be downward/upward to keep constant temperature, the self-fusing capability is realized under the condition of overvoltage or overcurrent, and the carbon nano tubes are automatically disconnected at the temperature of more than 200 ℃.

Claims

1. A metal-free heating element, the heating element comprising: multi-walled carbon nanotubes, polylactic acid, polybutylene terephthalate, and polybutylene adipate-co-terephthalate;

wherein, the component proportion is as follows:

multi-walled carbon nanotubes: 12 to 15 wt% of a binder,

polylactic acid: 10 to 14 wt% of a binder,

polybutylene terephthalate: 61 to 73 wt%, and

polybutylene adipate-co-terephthalate: 5 to 10 wt%.

2. The metal-free heating element according to claim 1, wherein the heating element is obtained by mixing the above components together and then heating and extruding for one-shot molding; or mixing the components and placing the mixture into a preset mold to be heated and molded at one time to obtain the product.

3. The metal-free heating element according to claim 1, wherein the heating element is a heating wire extruded to have a diameter of 3.5 to 4.0mm, or a heating sheet having a thickness of 3.5 to 4.0 mm.

4. A metal-free heating element according to claim 3, wherein the heating wire has a thickness of 3.75mm and a length of 1000 mm; when 12V direct current is applied to each heating wire, the current is 0.24A, and the temperature of each heating wire is about 45 ℃.

5. A heat generating pad, characterized by comprising:

-metal-free heating elements arranged in parallel within the heating mat, the heating elements being according to any one of claims 1-4;

connecting wires connecting the metal-free heating elements arranged in parallel;

a temperature sensor mounted inside the heating pad for sensing temperature and a temperature fuse for cutting off current;

a temperature regulator connecting the connecting line, the temperature sensor and the temperature fuse;

and an external adapter connected to the temperature regulator and converting the alternating current to direct current.

6. The heating pad according to claim 5, wherein a plurality of heating elements are provided, and the heating elements are connected in parallel by connecting lines; the connecting wire is connected to the first wire and is connected to the temperature regulator through the first wire; the connecting wire is a heating wire or a first electric wire directly.

7. A heating pad according to claim 5 or 6, wherein the heating element and the connecting wire are connected by insertion and injection bonding.

8. A heat generating pad according to claim 5 or 6, wherein the temperature sensor and the temperature fuse are connected to a temperature regulator through a second electric wire.

9. Use of a metal-free heating element in a heating mat, the heating element being a heating element according to any one of claims 1-4.