TWI845181B - Negative temperature coefficient temperature sensing material composition, negative temperature coefficient temperature sensing material and preparation system thereof - Google Patents

Abstract

The present invention provides a negative temperature coefficient temperature-sensitive material composition, a negative temperature coefficient temperature-sensitive material and a preparation system thereof. The negative temperature coefficient temperature-sensitive material composition includes: polyvinyl chloride resin, ester plasticizer, calcium carbonate, a mixture of zinc stearate and calcium stearate, antimony trioxide, a silicon-based complex, and a phenylethylene complex. The present invention also provides a negative temperature coefficient temperature-sensitive material preparation system, which includes: the raw materials of the aforementioned negative temperature coefficient temperature-sensitive material composition, a stirring device and an extruder; the stirring device includes a feeding unit for receiving the raw materials, and the extruder is connected to the stirring device. The stirring device is used to mix and stir the raw materials until they are plasticized to obtain a semi-finished product, and the extruder is used to form the negative temperature coefficient temperature-sensitive material from the semi-finished product.

Description

Negative temperature coefficient temperature sensing material composition, negative temperature coefficient temperature sensing material and preparation system thereof

This invention relates to a negative temperature coefficient (NTC) temperature-sensitive material composition, a negative temperature coefficient temperature-sensitive material and a preparation system thereof, in particular, an NTC temperature-sensitive material composition comprising polyvinyl chloride (PVC) resin, a preparation system using the aforementioned NTC temperature-sensitive material composition, and an NTC temperature-sensitive material prepared by the aforementioned preparation system.

Thermistor is a variable resistor, which means its resistance value will change with temperature. It can be mainly divided into positive temperature coefficient thermistor, negative temperature coefficient thermistor and critical temperature thermistor. Among them, NTC thermistor refers to the resistance value that decreases exponentially when the temperature increases. Since thermistors have high sensitivity within a specific temperature range, they are now widely used in temperature measurement, temperature control or temperature compensation components. In addition, through the thermal characteristics of a material that causes resistance changes due to temperature changes, it can also be used to protect a heating element.

In the design of a general heating component (such as a heating wire for an electric blanket), it usually includes an inner tube, a heating wire and a temperature-sensitive wire; wherein the heating wire is arranged in the inner tube in a spiral coil, and is mainly used for generating heat and can be kept constant in a specific temperature range; and the temperature-sensitive wire is spirally wound on the outer wall of the inner tube, and is mainly used for transmitting temperature control information to drive the heating wire to generate a specific temperature; the inner tube acts as an insulating medium to separate the heating wire and the temperature-sensitive wire to ensure normal operation between the two. In the prior art, the inner tube is usually made of a resin material that is not heat-sensitive. As a result, during the heating process of the heating wire, once the temperature control element used in conjunction with it fails, the heating component will directly heat up to the melting temperature of the inner tube, which will cause the heating wire and the temperature-sensitive wire to come into direct contact, causing permanent damage, making the product containing it unusable.

In view of the defects of the existing technology, the purpose of this invention is to provide an NTC temperature-sensitive material composition, which, when applied to a heating component, can help provide correct temperature information, thereby preventing the heating component from continuing to heat up when the matching temperature control element fails, causing damage to the product containing it.

Another purpose of the present invention is to provide an NTC temperature-sensitive material composition, wherein the prepared NTC temperature-sensitive material has good thermal stability.

To achieve the above-mentioned purpose, the present invention provides an NTC temperature-sensitive material composition, which includes: PVC resin, ester plasticizers, calcium carbonate, a mixture of zinc octadecanoate and calcium octadecanoate, antimony trioxide (Sb ₂ O ₃ ), a silicon-based complex, and a phenylethylene complex.

This creation contains the above-mentioned specific components at the same time, so that it has the thermal sensitivity of NTC. When it is applied to heating components, it can help provide correct temperature information; and the NTC temperature-sensitive material formed by the NTC temperature-sensitive material composition of this creation has excellent thermal stability and can be applied to more diversified products to enhance market value. In addition, the NTC temperature-sensitive material formed by the NTC temperature-sensitive material composition of this creation also has good pressure resistance, tear resistance, and anti-interference. When the heating wires, wires, and cables made of the aforementioned NTC temperature-sensitive materials are torn or squeezed by external forces, the wires will not break, thereby ensuring that they can operate normally and maintain their proper insulation performance between the wires.

Preferably, the degree of polymerization of the PVC resin is 800 to 2000; more preferably, the degree of polymerization of the PVC resin is 1200 to 1500, but not limited thereto. Specifically, the degree of polymerization of the PVC resin may be 800, 1000, or 1300.

According to the present invention, the ester plasticizer may include bis(2-ethylhexanoate) plasticizers, triisooctanoate plasticizers, phthalate plasticizers, adipate plasticizers or a combination thereof, but is not limited thereto. Specifically, the diisooctanoate plasticizer may include dioctyl terephthalate (DOTP) or diisooctyl phthalate (DEHP); the triisooctanoate plasticizer may include trioctyl trimellitate (TOTM); the phthalate plasticizer may include di(2-propylheptyl) phthalate (DPHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), or diisodecyl phthalate (DIISODECY PHTHALATE). The adipate plasticizer may include diisononyl adipate (DINA), a polymer of adipic acid with butanediol and ethylhexanol, or di(2-ethylhexyl) adipate (DOA). Preferably, the ester plasticizer may include trioctyl trimellitate, a polymer of adipic acid with butanediol and ethylhexanol, or a combination thereof.

In some embodiments, the ester plasticizer may include two or more different types of plasticizers at the same time; for example, the ester plasticizer may include a combination of the triisooctanoate plasticizer and the adipic acid ester plasticizer; or, the ester plasticizer may include a combination of two phthalate plasticizers, but is not limited thereto. Preferably, the ester plasticizer may be a combination of DINP and DBP, or a polymer of adipic acid, butanediol and ethylhexanol and trioctyl trimellitate.

Preferably, in the mixture of zinc stearate and calcium stearate, the weight ratio of zinc stearate to calcium stearate is 3:1 to 1:1, but not limited thereto. Specifically, the weight ratio of zinc stearate to calcium stearate may be 2:1, but not limited thereto.

Preferably, the silicon-based composite is a silicon dioxide composite, but not limited thereto. Specifically, the silicon dioxide composite can be quartz sand, but not limited thereto. Preferably, the average particle size of the quartz sand is 0.5 μm to 10 μm, but not limited thereto.

Preferably, the phenylethylene complex may include 1-(4-vinylphenyl)-1,2,2-triphenylethylene; further, the phenylethylene complex may include 1-(4-vinylphenyl)-1,2,2-triphenylethylene and 4-tert-butyl-1,2-benzenediol (TBC); wherein 4-tert-butyl-1,2-benzenediol is used as a stabilizer. Specifically, in the phenylethylene complex, the weight ratio of 1-(4-vinylphenyl)-1,2,2-triphenylethylene to 4-tert-butyl-1,2-benzenediol may be 98:2, etc., but is not limited thereto.

Preferably, based on the total weight of the NTC temperature-sensitive material composition, the content of the PVC resin may be 50 weight percent (wt%) to 55 wt%, but is not limited thereto.

Preferably, based on the total weight of the NTC temperature-sensitive material composition, the content of the ester plasticizer can be 22 wt% to 35 wt%, but is not limited thereto. In some embodiments, when the ester plasticizer is a combination of adipic acid, a polymer of butanediol and ethylhexanol, and trioctyl trimellitate, the content of the polymer of adipic acid, butanediol and ethylhexanol can be 6 wt% to 10 wt%, and the content of trioctyl trimellitate can be 16 wt% to 25 wt%; more preferably, the weight ratio of the polymer of adipic acid, butanediol and ethylhexanol to trioctyl trimellitate is 1:3.

Preferably, based on the total weight of the NTC temperature sensing material composition, the content of calcium carbonate may be 8 wt % to 10 wt %, but is not limited thereto.

Preferably, based on the total weight of the NTC temperature-sensitive material composition, the content of the mixture of zinc stearate and calcium stearate may be 2 wt % to 4 wt %, but is not limited thereto.

Preferably, based on the total weight of the NTC temperature sensing material composition, the content of antimony trioxide may be 1 wt % to 3 wt %, but is not limited thereto.

Preferably, based on the total weight of the NTC temperature sensing material composition, the content of the silicon-based composite can be 2 wt % to 4 wt %, but is not limited thereto.

Preferably, based on the total weight of the NTC temperature-sensitive material composition, the content of the phenylethylene complex may be 2 wt % to 4 wt %, but is not limited thereto.

In some embodiments, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, colorants or combinations thereof may be further added to the NTC temperature sensing material composition as needed, but are not limited thereto.

The invention also provides a NTC temperature-sensitive material preparation system, which includes: a raw material, a stirring device, and an extruder. The raw material is the aforementioned NTC temperature-sensitive material composition. The stirring device includes a feeding unit, which is used to receive the raw material; the stirring device is used to mix and stir the raw material until it is plasticized to obtain a semi-finished product. The extruder is connected to the stirring device; the extruder is used to form the semi-finished product into an NTC temperature-sensitive material.

According to the invention, the stirring device can be a vertical stirring cylinder, but is not limited thereto. Preferably, the temperature of the raw material in the stirring device can be 150°C to 155°C.

According to the present invention, the extruder may include a tubular barrel, an extrusion screw and a plurality of heating units; the extrusion screw is located in the tubular barrel; the plurality of heating units are fixed on the outer wall of the tubular barrel, and the heating temperature of the plurality of heating units is 140°C to 160°C.

In order to heat the semi-finished product more evenly, the multiple heating units are heated up in sequence, and the temperature of each heating unit is higher than the set temperature of the previous heating unit. Specifically, the heating unit closest to the stirring device has the lowest temperature, and relatively speaking, the heating unit farthest from the stirring device has the highest temperature; that is, the heating unit located in the lower material section of the extruder has the lowest set temperature, and the heating unit closest to the discharge port and die of the extruder has the highest temperature. For example, the heating unit located in the lower material section of the extruder has a set temperature of 140°C, which increases step by step to 145°C, while the set temperature of the die is set to 155°C.

This invention also provides an NTC temperature-sensitive material, which is produced by the aforementioned NTC temperature-sensitive material preparation system.

Preferably, after the NTC temperature-sensitive material is in an environment of 100°C for 500 hours, the resistance change rate may be no more than 20%; more preferably, after the NTC temperature-sensitive material is baked at 80°C for 500 hours, the resistance change rate may be no more than 15%.

Preferably, after the NTC temperature-sensitive material has been in an environment of 136°C for 168 hours, the resistance change rate may not be greater than 200%; more preferably, after the NTC temperature-sensitive material has been in an environment of 136°C for 168 hours, the resistance change rate may not be greater than 150%.

In some embodiments, the NTC temperature-sensitive material can be used to form an insulating material. Specifically, the NTC temperature-sensitive material can form an insulating layer of any form and structure and be disposed between any two or more non-interfering wires in wires and cables. When the wires are abnormally heated and reach a certain high temperature, the resistance of the NTC temperature-sensitive material drops to a very low value, so that the wires can be short-circuited, so that the wires no longer continue to heat up, thereby avoiding the possibility of fire and ensuring the safety of users.

In other embodiments, the NTC temperature-sensitive material can be used to manufacture an inner tube of a heating wire. The heating wire may include an inner tube, a heating wire and a temperature-sensitive wire; wherein the heating wire is disposed in the inner tube in a spiral coil, mainly used for generating heat and can be constant in a specific temperature range; and the temperature-sensitive wire is spirally wound on the outer wall of the inner tube, mainly used for transmitting temperature control information to drive the heating wire to generate a specific temperature; and the inner tube serves as an insulating medium to separate the heating wire and the temperature-sensitive wire. When the heating wire in the heating wire fails or other uncontrolled conditions occur and the heating wire continues to generate heat and the temperature rises to an excessively high temperature, the resistance of the inner tube will change with the temperature and its resistance will tend to be close to the resistance of the conductor. At this time, the heating wire and the temperature sensing wire will be connected to form a short circuit, so it can effectively avoid the danger of fire caused by the excessive temperature of the heating wire in the electric heating product (such as an electric blanket) containing the heating wire, thereby ensuring the safety of the user.

In this specification, if there is no special indication, the range expressed by "a small number to a large number" means that the range is greater than or equal to the small number and less than or equal to the large number. For example, if the content of the PVC resin is 50 wt% to 55 wt%, it means that the content range of the PVC resin is "greater than or equal to 50 wt% and less than or equal to 55 wt%".

The specific implementation methods of the present invention will be described below through the following embodiments and comparative examples. Those skilled in the art can easily understand the advantages and effects that can be achieved by the present invention through the contents of this manual, and make various modifications and changes without departing from the spirit of the present invention to implement or apply the contents of the present invention.

《 NTC Temperature Sensitive Material Composition》

Embodiment 1:

According to the content ratio shown in Table 1-1, each component is placed in a reaction container and mixed evenly to obtain the NTC temperature-sensitive material composition of Example 1. Table 1-1: Components, CAS No. and content of the NTC temperature-sensitive material composition of Example 1 Ingredients CAS NO. Content (wt%) PVC resin (degree of polymerization 1300) 9002-86-2 52.6 Calcium carbonate 471-34-1 8.4 Trioctyl trimellitate 6422-86-2 20.5 Adipic acid, polymer with butanediol and ethylhexanol 63149-79-1 8.4 Mixture of zinc stearate and calcium stearate (weight ratio 2:1) 557-05-1/1592-23-0 3.2 Antimony trioxide 1309-64-4 1.6 Quartz sand 14808-60-7 2.5 1-(4-vinylphenyl)-1,2,2-triphenyl]ethylene 1351272-41-7 2.8

Comparative Example 1:

According to the content ratio shown in Table 1-2, each component is placed in a reaction container and mixed evenly to obtain the NTC temperature-sensitive material composition of Comparative Example 1. Among them, the main difference between Comparative Example 1 and Example 1 is that Comparative Example 1 contains a polymer amide complex but does not contain a phenylethylene complex, and the content of each component is slightly different. Table 1-2: Components, CAS No. and content of the NTC temperature-sensitive material composition of Comparative Example 1 Ingredients CAS NO. Content (wt%) PVC resin (degree of polymerization 1300) 9002-86-2 52.4 Calcium carbonate 471-34-1 8.4 Trioctyl trimellitate 6422-86-2 20.2 Adipic acid, polymer with butanediol and ethylhexanol 63149-79-1 8.2 Mixture of zinc stearate and calcium stearate (weight ratio 2:1) 557-05-1/1592-23-0 3.2 Antimony trioxide 1309-64-4 1.7 Quartz sand 14808-60-7 2.8 Polymer amide complex (polyether ester amide block copolymer) 77402-38-1 3.1

As shown in FIG1 , the NTC temperature-sensitive material preparation system 1 of the present embodiment comprises a raw material M, a stirring device 10 and an extruder 20. The raw material M is the NTC temperature-sensitive material composition of Embodiment 1. The stirring device 10 is a vertical stirring cylinder, which includes a feeding unit (not shown), and the feeding unit is used to receive the raw material M; the stirring device 10 is used to mix and stir the raw material M until it is plasticized to obtain a semi-finished product. The extruder 20 is connected to the stirring device 10; the extruder 20 is used to extrude and granulate the semi-finished product to obtain an NTC temperature-sensitive material. The raw material is heated to a temperature of 150°C to 155°C due to stirring and reaction in the stirring device 10.

Please refer to Figure 2 again, the extruder 20 includes a bottom plate 21, a support plate 22, a tubular barrel 23, an extrusion screw 24, a speed reducer 25, a heating unit 26, a servo motor (not shown), an opening and closing mechanism 27, a switching mechanism 28, a feed hopper 29, a discharge port (not shown), a die head 30, a cooling tank 31, a guide roller 32 and a pelletizer 33. Two support plates 22 are symmetrically fixed on the upper surface of the bottom plate 21, a tubular barrel 23 is fixed on the top of the support plate 22, the extrusion screw 24 is located in the tubular barrel 23, and the inner wall of the tubular barrel 23 is rotatably connected to the extrusion screw 24 through a bearing. A reducer 25 is fixed to one end of the upper surface of the bottom plate 21, and the output end of the reducer 25 is fixedly connected to the extrusion screw 24. A servo motor 26 is fixed to the other end of the reducer 25, and the output end of the servo motor 26 is fixedly connected to the input end of the reducer 25. A feed hopper 29 is fixed to one end of the top of the tubular barrel 23 near the reducer 25 to receive the semi-finished product. A plurality of heating units 26 are fixed at equal intervals on the outer side wall of the tubular barrel 23. The end of the tubular barrel 23 far from the speed reducer 25 is fixed with a discharge port (i.e., one end opposite to the feed hopper 29), and the discharge port is hinged with one end of the opening and closing mechanism 27; the other end of the opening and closing mechanism 27 is fixed with a switching mechanism 28, and four die heads 30 are fixed at equal distances on the opposite side of the switching mechanism 28, and the diameters of the four die heads 30 are all different. A cooling groove 31 is fixed on the upper surface of the bottom plate 21 near the die head 30, and the inner wall of the cooling groove 31 is symmetrically rotated and connected to a guide roller 32 through a bearing, and a pelletizer 33 is fixed at the end of the cooling groove 31 (i.e., far from the die head 30). Among the multiple heating units 26, the temperature of the one closest to the feed hopper 29 is set to 140°C, and then gradually increases to 145°C when the temperature of the one closest to the discharge port is set, and the temperature of the die head 30 is set to 155°C.

Furthermore, the switching mechanism 28 includes a worm wheel (not shown), a worm rod (not shown), and a turntable 281, wherein the die head 30 is fixed equidistantly on a surface of the turntable 281; a worm wheel and a worm rod are fixed on the opposite surface of the turntable 281; and the worm rod is engaged and connected with the worm wheel. Specifically, the rotation of the worm rod can drive the worm wheel to rotate, and then drive the turntable 281 to rotate, so that the turntable 281 rotates the die head 30 to be used to align with one end of the channel connected to the discharge port. Therefore, when it is necessary to produce NTC temperature-sensitive material particles of different sizes (particle diameters), the corresponding die head 30 can be quickly replaced.

Test example 1 :

In order to confirm that the NTC temperature-sensitive material of the present invention can still maintain similar NTC characteristics after long-term use, and prove that it has good thermal stability, the heating wire inner tubes (6 identical samples) made of the NTC temperature-sensitive material of Example 1 and the heating wire inner tubes (6 identical samples) made of the NTC temperature-sensitive material of Comparative Example 1 were subjected to aging analysis tests at 80°C: the heating wire inner tubes were taken out after continuous baking for 96 hours, 192 hours, 312 hours, 408 hours and 504 hours, and the resistance change relationship of the heating wire inner tubes in response to temperature changes (35°C to 140°C) was detected under the aging state at each time point, wherein the unit of the resistance of the heating wire inner tube is kilo-ohm (KΩ). To ensure the experimental significance of the characteristic analysis, the inner tubes of each heating wire are made in the same way and analyzed under the same test conditions, and the resistance values of the inner tubes of each heating wire at different temperatures are recorded in Table 2-1 and Table 2-2. In addition, the test conditions are as follows: 1. Resistance tester: V-TECH APS10005 2. Inner tube length: 5 meters 3. Applied voltage: 120 volts (V) 4. Frequency: 60 Hz (Hz) 5. Loop resistance: 20 KΩ

Table 2-1 The resistance values of the inner tube of the heating wire made of the NTC temperature-sensitive material of Example 1 measured at 35°C to 140°C before baking, after baking at 80°C for 96 hours, 192 hours, 312 hours, 408 hours and 504 hours (unit: KΩ) Temperature(℃) Unbaked(KΩ) 96 hours (KΩ) 192 hours (KΩ) 312 hours (KΩ) 408 hours (KΩ) 504 hours (KΩ) 35 1826 1826 1826 1900 1980 1980 45 853 853 869 886 903 960 55 338 341 349 358 370 387 65 141 144 149 151 155 163 75 64 64 65 69 70 72 85 33.3 33.9 34.7 35.2 35.7 36.3 95 18.4 18.7 19.1 19.4 19.8 20.3 100 14.2 14.6 15.0 15.3 15.6 15.9 105 11.0 11.3 11.5 11.7 12.0 12.1 110 8.3 8.5 8.7 8.9 9.0 9.2 115 6.7 6.8 7.0 7.1 7.1 7.3 120 5.6 5.7 5.8 5.8 5.9 6.0 125 4.7 4.9 4.9 5.1 5.1 5.2 130 4.0 4.1 4.1 4.2 4.2 4.3 135 3.3 3.4 3.4 3.5 3.5 3.6 140 2.9 3.0 3.0 3.1 3.1 3.2

Table 2-2 The resistance values of the inner tube of the heating wire made of the NTC temperature-sensitive material of Comparative Example 1 at 35°C to 140°C after unbaking, continuous baking for 96 hours, 192 hours, 312 hours, 408 hours and 504 hours (unit: KΩ) Temperature(℃) Unbaked(KΩ) 96 hours (KΩ) 192 hours (KΩ) 312 hours (KΩ) 408 hours (KΩ) 504 hours (KΩ) 35 1826 1826 1826 1980 1980 2162 45 837 837 853 1023 1023 1047 55 336 358 373 446 465 470 65 139 141 155 183 190 191 75 64 65 71 81 83 85 85 33.5 34.1 37.3 40.8 41.0 42.3 95 18.9 19.4 21.3 22.9 22.7 23.8 100 14.5 15.1 16.6 18.1 18.0 18.9 105 11.0 11.8 12.9 14.1 13.9 14.8 110 8.5 9.4 10.3 11.5 11.5 12.1 115 6.9 7.7 8.3 9.5 9.4 9.9 120 5.7 6.3 6.8 7.8 7.7 8.2 125 4.8 5.2 5.6 6.4 6.3 6.7 130 4.1 4.4 4.7 5.4 5.3 5.6 135 3.5 3.6 3.9 4.5 4.4 4.7 140 3.0 3.0 3.2 3.7 3.7 4.0

In addition, as shown in Figures 3 and 4, respectively, the resistance values of the inner tubes of the heating wires made of the NTC temperature-sensitive materials of Example 1 and Comparative Example 1 before and after continuous baking at 80°C for 504 hours in Tables 2-1 and 2-2 are plotted as the temperature changes (35°C to 140°C) and the resistance values are plotted as the temperature changes (35°C to 140°C).

Furthermore, the resistance change rate of the inner tube of the heating wire made of the NTC temperature-sensitive material of Example 1 after continuous baking for 504 hours relative to that of the unbaked (i.e., unaged) is calculated from 35°C to 140°C, and the resistance change rate of the inner tube of the heating wire made of the NTC temperature-sensitive material of Comparative Example 1 after continuous baking for 504 hours relative to that of the unbaked (i.e., unaged) is calculated. The two sets of resistance change rates are listed in Tables 2-3, and the data are plotted into a relationship diagram between temperature and resistance change rate as shown in FIG5 . For example, the resistance of the heating wire inner tube made of the NTC temperature-sensitive material of Example 1 before baking at 35°C is 1826 KΩ; when the heating wire inner tube is baked at 80°C for 504 hours, the resistance measured at 35°C is 1980 KΩ. Therefore, the resistance change rate is calculated according to the following formula: (1980-1826)/1826 x 100% = 8%.

Table 2-3 Resistance change rate after aging at 35℃ to 140℃ for the inner tube of the heating wire made of the NTC temperature-sensitive material of Example 1 and Comparative Example 1 after being baked at 80℃ for 504 hours Temperature(℃) Resistance change rate of the inner tube of the heating wire made of NTC temperature-sensitive material after aging in Example 1 Resistance change rate of the heating wire inner tube made of NTC temperature-sensitive material after aging in comparative example 1 35 8% 18% 45 13% 25% 55 14% 40% 65 16% 37% 75 12% 32% 85 9% 27% 95 11% 26% 100 12% 30% 105 10% 34% 110 11% 42% 115 9% 44% 120 9% 44% 125 11% 39% 130 9% 38% 135 9% 36% 140 12% 36%

Test example 2 :

The heating wire inner tube made of the NTC temperature-sensitive material of Example 1 and the heating wire inner tube made of the NTC temperature-sensitive material of Comparative Example 1 were subjected to aging analysis tests at 136°C respectively: the heating wire inner tube was taken out after continuous baking for 96 hours, and the resistance change relationship of the heating wire inner tube in response to the temperature change (35°C to 140°C) was detected, wherein the unit of the resistance of the heating wire inner tube is kilo-ohm. To ensure the experimental significance of the characteristic analysis, each heating wire inner tube was made in the same way and analyzed under the same test conditions, and the test conditions were the same as those of the above-mentioned Test Example 1. The resistance values of each heating wire inner tube at different temperatures are recorded in Table 3-1. In addition, as shown in FIG. 6 and FIG. 7 , respectively, the resistance values of the inner tube of the heating wire made of the NTC temperature-sensitive material of Example 1 and Comparative Example 1 before and after continuous baking at 136°C for 168 hours in Table 3-1 are plotted as the temperature changes (35°C to 140°C) and the resistance values are plotted as the temperature changes (35°C to 140°C).

Table 3-1 The resistance values of the inner tubes of the heating wires made of the NTC temperature-sensitive materials of Example 1 and Comparative Example 1 measured at 35°C to 140°C before baking and after baking for 168 hours (unit: KΩ) Temperature(℃) Inner tube of heating wire made of NTC temperature sensitive material of Example 1 Comparative Example 1: Heater inner tube made of NTC temperature sensitive material Unbaked(KΩ) 168 hours (KΩ) Unbaked(KΩ) 168 hours (KΩ) 35 1826 2162 1826 2804 45 853 1243 837 2380 55 338 565 336 1980 65 141 241 139 1123 75 64 109 64 545 85 33.3 57.5 33.5 265.7 95 18.4 31.8 18.9 138.4 100 14.2 27.7 14.5 105.0 105 11.0 23.6 11.0 80.4 110 8.3 20.0 8.5 62.9 115 6.7 17.2 6.9 51.0 120 5.6 14.9 5.7 39.9 125 4.7 12.6 4.8 35.6 130 4.0 10.4 4.1 32.5 135 3.3 8.9 3.5 27.7 140 2.9 7.6 3.0 23.7

Furthermore, the resistance change rate of the inner tube of the heating wire made of the NTC temperature-sensitive material of Example 1 after being baked at 136°C for 168 hours compared to the unbaked (i.e., unaged) one at 35°C to 140°C was calculated, and the resistance change rate of the inner tube of the heating wire made of the NTC temperature-sensitive material of Comparative Example 1 after being baked at 136°C for 168 hours compared to the unbaked (i.e., unaged) one at 35°C to 140°C was calculated. The two sets of resistance change rates are listed in Table 3-2, and the data are plotted into a relationship graph between temperature and resistance change rate as shown in FIG8 .

Table 3-2 Resistance change rate after aging at 35℃ to 140℃ for the inner tube of the heating wire made of the NTC temperature-sensitive material of Example 1 and Comparative Example 1 after being baked at 136℃ for 168 hours Temperature(℃) Resistance change rate of the inner tube of the heating wire made of NTC temperature-sensitive material after aging in Example 1 Resistance change rate of the heating wire inner tube made of NTC temperature-sensitive material after aging in comparative example 1 35 18% 54% 45 46% 184% 55 67% 490% 65 71% 708% 75 71% 748% 85 73% 694% 95 73% 632% 100 94% 624% 105 114% 628% 110 140% 640% 115 157% 642% 120 169% 603% 125 168% 643% 130 162% 694% 135 174% 698% 140 164% 701%

Experimental Results Discussion

As can be seen from Figures 3 and 6, the NTC temperature-sensitive material prepared by the NTC temperature-sensitive material preparation system of the present invention does have a thermally sensitive temperature characteristic, and its resistance decreases exponentially when the temperature rises. In the temperature range of 35°C to 75°C, the resistance value of the inner tube decreases sharply from about 1800 KΩ at 35°C as the temperature rises, but the resistance value at 75°C remains above 60 KΩ, and still has sufficient insulation to ensure that the temperature-sensitive wire and the heating wire do not interfere with each other. When the temperature of the inner tube reaches 130°C, its resistance value has dropped below 5 KΩ; when the temperature of the inner tube reaches 140°C, its resistance value is closer to 0, which can make the heating wire and the temperature sensing wire electrically connected and short-circuited, so the circuit cannot maintain the original loop, so that the heating wire no longer heats up. In addition, existing electric blankets are often filled with cotton or other fiber materials, and the ignition point of cotton and most fiber materials is above 300°C. Therefore, the inner tube made of the NTC temperature-sensitive material of this invention can cause a short circuit between the heating wire and the temperature sensing wire at 140°C, so it can ensure that the heating wire stops heating before it reaches the ignition point of the cotton or other fiber materials in the electric blanket, thereby ensuring the safety of the user.

In addition, it can be seen from Figures 5 and 8 that, compared with other materials formed by NTC temperature-sensitive material compositions that also contain PVC resin, the inner tube made of the NTC temperature-sensitive material of Example 1 can maintain a resistance value similar to that before aging when the temperature changes, even after being baked at a high temperature for a long time to accelerate aging, and has a lower resistance change rate. This proves that the NTC temperature-sensitive material made of the NTC temperature-sensitive material composition of this invention does have good thermal stability.

The above-mentioned embodiments are only given for the convenience of explanation, but the embodiments are not intended to limit the scope of the patent application of this creation; any other changes, modifications, etc. that do not deviate from the disclosed content of this creation should be included in the patent scope covered by this creation.

1:NTC temperature sensitive material preparation system M:Raw material 10:Stirring device 20:Extruder 21:Bottom plate 22:Support plate 23:Tube barrel 24:Extrusion screw 25:Speed reducer 26:Heating unit 27:Opening and closing mechanism 28:Switching mechanism 281:Turntable 29:Feed hopper 30:Die head 31:Cooling tank 32:Guide roller 33:Pelletizer

Figure 1 is a schematic diagram of the NTC temperature-sensitive material preparation system of this invention. Figure 2 is a schematic diagram of the extruder. Figure 3 is a relationship diagram between the resistance value and the temperature change of the NTC temperature-sensitive material prepared by Example 1 before baking and after baking at 80°C for 504 hours. Figure 4 is a relationship diagram between the resistance value and the temperature change of the NTC temperature-sensitive material prepared by Comparative Example 1 before baking and after baking at 80°C for 504 hours. Figure 5 is a relationship diagram between the temperature change and the resistance change rate of the NTC temperature-sensitive material prepared by Example 1 and Comparative Example 1 after baking at 80°C for 504 hours. Figure 6 is a relationship diagram between the resistance value and the temperature change of the NTC temperature-sensitive material prepared by Example 1 before baking and after baking at 136°C for 168 hours. Figure 7 is a graph showing the relationship between the resistance value and the temperature change of the NTC temperature-sensitive material prepared by Comparative Example 1 before baking and after baking at 136°C for 168 hours. Figure 8 is a graph showing the relationship between the temperature change and the resistance change rate of the NTC temperature-sensitive material prepared by Example 1 and Comparative Example 1 after baking at 136°C for 168 hours.

without

Claims (9)

A negative temperature coefficient temperature sensing material composition, comprising: polyvinyl chloride resin; ester plasticizer; calcium carbonate; a mixture of zinc stearate and calcium stearate; antimony trioxide; a silicon-based compound; and a phenylethylene compound; wherein, based on the total weight of the negative temperature coefficient temperature sensing material composition, the content of the polyvinyl chloride resin is 50 weight percent to 55 weight percent; the content of the ester plasticizer is 22 weight percent to 35 weight percent; the content of the calcium carbonate is 8 weight percent to 10 weight percent; the content of the mixture of zinc stearate and calcium stearate is 2 weight percent to 4 weight percent; the content of antimony trioxide is 1 weight percent to 3 weight percent; the content of the silicon-based compound is 2 weight percent to 4 weight percent; and the content of the phenylethylene compound is 2 weight percent to 4 weight percent. The negative temperature coefficient temperature-sensitive material composition as described in claim 1, wherein the ester plasticizer comprises diisooctanoate plasticizer, triisooctanoate plasticizer, phthalate plasticizer, adipate plasticizer or a combination thereof. The negative temperature coefficient temperature sensitive material composition as described in claim 1, wherein the ester plasticizer comprises trioctyl trimellitate, a polymer of adipic acid, butanediol and ethylhexanol or a combination thereof. The negative temperature coefficient temperature sensitive material composition as described in claim 1, wherein the phenylethylene complex comprises 1-(4-vinylphenyl)-1,2,2-triphenylethylene. The negative temperature coefficient temperature-sensitive material composition as described in claim 1, wherein the silicon-based composite is a silicon dioxide composite. A negative temperature coefficient temperature-sensitive material preparation system, comprising: a raw material, which is a negative temperature coefficient temperature-sensitive material composition as described in any one of claims 1 to 5; a stirring device, which comprises a feeding unit, the feeding unit is used to receive the raw material; the stirring device is used to mix and stir the raw material until it is plasticized to obtain a semi-finished product; and an extruder, which is connected to the stirring device; the extruder is used to form a negative temperature coefficient temperature-sensitive material from the semi-finished product. The negative temperature coefficient temperature-sensitive material preparation system as described in claim 6, wherein the extruder comprises a tubular barrel, an extrusion screw and a plurality of heating units; the extrusion screw is located in the tubular barrel; the plurality of heating units are fixed on the outer wall of the tubular barrel, and the heating temperature of the plurality of heating units is 140°C to 160°C. A negative temperature coefficient temperature sensitive material, which is produced by the negative temperature coefficient temperature sensitive material preparation system as described in claim 6 or 7. The negative temperature coefficient temperature-sensitive material as described in claim 8, wherein the resistance change rate of the negative temperature coefficient temperature-sensitive material after being baked at 80°C for 500 hours is no more than 15%.

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