JPS63270869A - Production of yarn like heat generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an efficient method for producing an electrically heated filamentous heating element that is highly flexible and durable for long-term use.

[Prior Art] Flexible heat-generating wires made of thin metal wires have been used for keeping instruments warm or heating them, but in particular electric wool wires5,
It has become widely used in consumer products such as electric carpets, and due to its convenience, it is likely to be used in more and more products in the future.

Conventionally, resistors made of fine metal wires such as stainless steel wires and nichrome wires have been used in these heating elements, but if the above-mentioned products are required to be flexible, flexible Some examples include those in which ultra-thin resistance wire is spirally wound around a core yarn, and those in which carbon is fixed to a fabric using a resin binder.

However, none of these materials can satisfy the required performance in terms of bending resistance, abrasion resistance, etc., and also lacks flexibility, so improvements are required.

An attempt was made to solve this problem by
There is a 471 publication. This increases the flexibility of the heating element by providing a rubber or plastic layer containing conductive fine particles around the core yarn. However, the manufacturing method is that of electric wire manufacturing, and uses large-scale equipment consisting of a conductive rubber or plastic heating and melting section, a heat-insulating piping section, and a melt-coating section.

The melt-coated portion is provided with two pores each having a diameter of 1 m or less for introducing and extracting the core yarn, and is kept at a high temperature that allows the rubber or plastic to have fluidity. Therefore, the operation of passing the core yarn through the two pores is very difficult to operate. Moreover, although the flexibility level of the obtained heating element is improved compared to thin metal wire, it is used in the clothing field such as rider suits, diaper suits, inner suits, gloves, shoes, etc., and requires a high degree of bending resistance such as electric blankets. In the field where it is used, its level is extremely low, and it has not yet been put into practical use.

Further, Japanese Utility Model Publication No. 39-37687 discloses a method in which a solution of a resin containing conductive fine particles is applied to a core yarn and then fixed in a solvent.

Coating is a method in which the core yarn is immersed in a solution and then excess solution is removed through pores, slits, etc., and the equipment is simpler and the operability is slightly better than in the melt coating method described above.

However, the heating element obtained by this method has uneven temperature when energized because the solution cannot be applied uniformly, resulting in burns and
There is even a possibility of starting a fire. Therefore, an appropriate method for producing filamentous heating elements is not recognized.

In addition, Japanese Patent Application Laid-Open No. 109321/1984 is an attempt to create a highly flexible heating element.

This is done by softening the nylon conjugate filament by heating or swelling it with a swelling agent.
Carbon particles are fixed to the surface layer of a filament to form a thread-like heating element. This heating element has too high a resistance value per length and is not suitable for use as a heating element. Further, it is difficult to uniformly fix carbon particles, and therefore the resistance value varies widely, making it impossible to stably supply the required resistance value industrially.

[Problems to be Solved by the Invention] The present invention improves these conventional problems, and provides a fabric with small variations in resistance value, high flexibility, good adhesion between the conductive layer and the core yarn, and bendable, To efficiently manufacture a thread-like heating element with good operability and which is difficult to peel off due to wear etc. and can be used stably for a long period of time.In order to solve the above problems, the thread-like heating element of the present invention has the following features. It has a configuration. That is, a synthetic resin solution in which conductive fine particles are suspended is adhered to the core thread while being measured using a metering device, then coagulated in a coagulation bath, and then dried and fixed to form a conductive layer of synthetic resin containing conductive fine particles dispersed therein. This is a method for manufacturing a filamentous heating element, characterized in that it is formed on the core yarn.

The main point of the present invention is to promote solvent removal by using a coagulation bath, improve the total drying efficiency including the drying process, and increase the production rate.

The overall process suitably used in the present invention will be specifically explained by giving an example.

In FIG. 1, the core yarn 1 is run through each process by drive systems 2 and 3. After the unwound core yarn 1 passes through a gate tensor 4, it is coated by a coating device 5 with a synthetic resin solution in which conductive fine particles are suspended. The coated yarn is soaked in a coagulation bath 6.
The solvent is removed by The coagulation bath is filled with a coagulation liquid.

A plurality of coagulation baths may be installed, and in that case, it is preferable to lower the coagulation bath concentration on the downstream side in order to achieve smooth coagulation.

The liquid valve is removed from the core yarn that has come out of the coagulation bath by a draining device 7 using compressed air before the drying process. A washing bath can also be provided before the coagulation bath and the draining device.

In the present invention, the drying step 8 is essential. The area around the core yarn that has passed through the above process contains, in addition to the solid content of the synthetic resin solution, some residual solvent and coagulation bath components that have diffused inside. Therefore, the resistance value per unit length of the core yarn varies greatly depending on the residual solvent and coagulation bath components, and the resistance value gradually changes due to natural drying, making it impossible to control production. Not only that, uneven temperature also causes problems in the performance of the final product as a heater.

For the above purpose, in the drying step 8, the residual solvent is removed by a known drying method, such as ordinary ventilation drying. In the drying step 8, in addition to the case where the thread is installed after the draining device as shown in Fig. 1, after passing through the coagulation bath, the thread is wound without going through the drying step, and the wound thread 9 is put into a dryer and completely dried. Furthermore, by using both methods,
Drying becomes more reliable. However, in terms of equipment, it is preferable to completely dry the material before winding it up, and when winding it up without going through a drying process, the winding system is required to have no stickiness.

An example of another process suitably used in the present invention is shown in FIG.

The core yarn runs at a constant speed by the supply roller 2 and the take-up roller 3. The core yarn 1 enters the adhesion device 5 from below, is coated with a synthetic resin solution in which conductive fine particles are suspended, and immediately drawn out into the coagulation bath 6 after being discharged. The solvent is removed under the same conditions as in the first example, and then the product is led to the drying step 8. Although FIG. 2 shows a method in which the core yarn is drawn out vertically upward, there is no problem in drawing it out horizontally or diagonally upward.

Another important point of the present invention is that when attaching the synthetic resin solution in which conductive fine particles are suspended to the core yarn, the synthetic resin solution is measured while being attached using a metering device. Thereby, the core yarn can be uniformly coated with the synthetic resin layer containing conductive fine particles dispersed therein, and the weight variation Cv value in the yarn length direction of the filamentous heating element can be made 6% or less.

This in turn makes it possible to reduce the variation in resistance value per length, and when the product is made into a final product, the temperature unevenness can be made to the same level as that using conventional thin metal wires.

The measured synthetic resin solution is transferred from the measuring device to the adhering device and is applied to the core yarn. The attachment device may be a known one, but in order to continuously attach a constant amount to the core yarn, it is preferable that the distance from the discharge hole of the synthetic resin solution to the time when the core yarn leaves the attachment device is short. It is important for the attachment device to have good thread hooking properties, and for this purpose it is preferably used that has a discharge hole drilled in the thread guide for the core thread. In addition, since the thread path of the core thread does not move within the attachment device, V
It is particularly preferable to use a yarn guide as the adhering device, which has a yarn guide groove of any one of a groove, a U-shape, and a flat groove, and has discharge holes bored in every quarter of the yarn guide groove. FIG. 3 shows an example of a top view of the thread guide. The part indicated by the broken line is the transfer path for the measured synthetic resin solution. Figure 3(a) is V
(b) is a U-shaped groove, and (C) is a flat groove. For more complete coverage, it is preferable to install a plurality of yarn guides close to the core yarn from different directions. As another embodiment of the yarn path guide, one in which a plurality of discharge holes are provided in the yarn path is preferably used. This is shown in FIG. 4, and this guide is advantageous in that the synthetic resin solution can be uniformly coated on the core yarn with one guide.

The yarn guide attachment device described above is suitable for the process shown in FIG. A suitable deposition device for both FIGS. 1 and 2 will now be described. It has a structure similar to the coating part of a wire coating device, and as shown in FIG. This is a method of coating the resin and drawing it out from the discharge hole of the die 13. The diameters of these two holes should be designed to prevent fuzzing of the core yarn, backflow of the synthetic resin solution to the nipple side, uneven coating of the synthetic resin solution, etc. The pore diameter D2 is preferably designed as follows: d+0.05≦D1≦d+0.4 DI<D2≦2. The unit of the above formula is m, and d is a value corresponding to the diameter of the core yarn, which is calculated as follows. Here, the unit of fineness and density is denier, 9/cnf.

As the material for the core thread used in the present invention, synthetic fiber or natural fiber thread is used. It is sufficient that these materials maintain stable performance for a long period of time at temperatures normally used as heating elements, that is, in the range of 20 to 100'C, and have good adhesion to the conductive layer. polyamide, polyester,
Thermoplastic synthetic fibers such as polyolefins are non-hygroscopic,
It is preferable because it has good chemical resistance, little thermal deterioration in the above temperature range, and has a fuse function that blows out if abnormal heating occurs locally. Also,
By using heat-resistant fibers such as aromatic polyamide, polybenzimidazole, polyphenylene triazole, polyoxadiazole, polyimide, and thermosetting resin fibers, the usable temperature range can be increased and the product life can be extended gracefully. It is preferable because it has the following advantages.

The form of the core yarn used in the present invention is such that it has good adhesion with synthetic resin, good absorption of synthetic resin solution, and the surface characteristics of the filament heating element when dried and fixed after absorption, i.e., smooth without protrusions or thick and thin. The filament heating element has a flat surface, a non-flat cross section, and a filament heating element with excellent resistance to external forces, such as tensile strength, elongation, initial Young's modulus, bending resistance, and abrasion resistance. It can be selected as appropriate depending on the application, taking into consideration the following factors: in particular,
Examples include spun yarns, burnt spun yarns, flat yarns, bulky processed yarns, twisted yarns, double yarns, egg yarns, etc., highly entangled yarns processed with fluid processing, taslan yarns, bimetallic composite fibers of synthetic fibers, and asymmetric cooling systems. It will be done.

The synthetic resin containing dispersed conductive fine particles used in the present invention is not particularly limited, but is suitable as long as it maintains stable performance against temperature and has excellent adhesiveness, bending resistance, abrasion resistance, etc. Examples of resins that can be used include polyurethane resins, acrylic resins, butyral resins, etc.
A flexible one is preferably selected.

As the conductive fine particles used in the present invention, for example,
Representative examples include carbon particles and metal particles. For example, various types of carbon black can usually be used as carbon particles, and the particle size is as follows:
1 to 500 TrLμ is preferable, especially 10 to 20
0TrLμ is preferably used.

Also, graphite can be used as carbon particles,
As the graphite, natural graphite, ie, phosphorous graphite, flaky graphite, raw graphite, or artificial graphite with a size of 1 to 100 μm is preferably used, and in particular, phosphorous graphite or flaky graphite with a size of 1 to 100 μm is preferably used. Those having a size of ~50 μm are preferably used. Furthermore, it is also preferable to use a mixture of carbon black and graphite as the carbon particles.

The amount of carbon particles used can be changed as appropriate depending on the desired resistance value. In order to obtain the desired resistance value as a heating element,
The amount of carbon particles in the resin solution is preferably 5 to 25% by weight, particularly preferably 7 to 15% by weight.

A synthetic resin solution in which such conductive fine particles are suspended exhibits structural viscosity and its viscosity increases several times when it is left standing. For this reason, the efficiency of the measuring device described later deteriorates, and uneven adhesion of the synthetic resin solution occurs. therefore,
As a remedy for this, it is preferable to stir the stored synthetic resin solution so that it always remains in a fluid state before spreading.

The resistance value of the filamentous heating element of the present invention can be appropriately set depending on the content of carbon particles dispersed in the synthetic resin, the thickness of the laminated layers, etc. For example, with the above formulation, a resistance value of 1 to 100 Ω/m can be obtained.

The volume resistivity of the resin at this time is approximately 0.01 to 10 Ω·cm, depending on the thickness of the thread. The conductive fine particles and the synthetic resin used in combination with the conductive fine particles can be selected depending on the purpose. It is also possible to reduce the resistance value by further twisting a plurality of filamentous heating elements to make them thicker.

An example of the method for manufacturing the filamentous heating element of the present invention will be described below.

Preparation process> Semi-slight core yarn: Prepare yarn without knots.

Preparation of resin suspension of conductive fine particles: A synthetic resin solution is prepared by dissolving and suspending the resin and conductive fine particles in an appropriate solvent.

The solvent for the synthetic resin used in the present invention may be any solvent that can dissolve the synthetic resin. For example, in the case of polyurethane resin, N-N-diethylformamide, N-
N''-diethylformamide, N-N''-dimethylacetamide.

Dimethyl sulfoxide, tetrahydrofuran.

DiAxane, hexamethylphosphoramide, or a mixed solvent containing these is used.

At this time, it is preferable to adjust the viscosity of the synthetic resin solution to 1 to 1000 voices in terms of uniform adhesion and discharge efficiency of the metering device, and more preferably to 2 to 200 voids. In addition, it is preferable to adjust the solid content of the synthetic resin solution, that is, the weight ratio of components other than the solvent, to 10 to 50% by weight from the viewpoint of energy saving in the drying step after deposition and workability in the suspension and dissolution steps. The synthetic resin solution is sealed in a closed container to prevent evaporation of the solvent.

Measuring and Adhesion Step> While stirring the synthetic resin solution in which conductive fine particles are suspended, it is transferred from the closed container to a measuring device through piping. □As the metering device, a known metering pump, particularly a gear pump, is suitably used.

One of the purposes of the present invention is to reduce the variation in the resistance value of the strands, but by measuring the synthetic resin solution using a metering device and attaching it to the core thread, the variation in the adhesion in the axial direction of the strands can be reduced. can be made extremely small. The measured amount of the synthetic resin solution is led to the above-mentioned coating device and coats the core yarn. In order to reduce adhesion variations, it is preferable to feed the core yarn to the adhesion device at a constant speed. For that purpose (before and after the adhesion device)! The yarn after the drying process is a-
A method of supplying and withdrawing by means of a roller is preferably used.

In order to attach the thread with appropriate tension, it is also preferable to tension the thread using around 17 rollers.

Solidification Step> The greatest feature of the present invention is that it includes a solidification step, and the outline is as described above.

The coagulating liquid used in the present invention is one that is a non-solvent for the synthetic resin and is miscible with the solvent. For example, when using polyurethane resin as a synthetic resin, water, methanol, ethanol, propatool,
A mixture of butanol, ethylene glycol, acetone, methyl ethyl ketone, etc., and a mixture of these non-solvents and a polymer solvent to an extent that does not dissolve the polyurethane resin, such as N-N--dimethylformamide/methyl ethyl ketone, N A solution of -N"-dimethylformamide/water is used. Among these, an aqueous solution of a solvent for the synthetic resin is preferably used as the composition of the coagulation liquid. At this time, if the concentration of the coagulation liquid is too low, The synthetic resin solution rapidly solidifies and micro-shrinkage occurs, so that good resin coating cannot be achieved.On the contrary, if the concentration is too high.

The solvent from the synthetic resin solution is not sufficiently removed, and the drying efficiency cannot be improved. From the above points, the concentration of the coagulating liquid is preferably 8% or more and 80% or less. The residence time of the core thread in the coagulation bath should be 1 second or more from the viewpoint of coagulation speed and drying efficiency.
It is preferably less than seconds. Since the concentration of the coagulating liquid does not change over time, it is necessary to constantly control the coagulating liquid, and as means for this, it is preferable to stir and circulate the coagulating liquid. In addition, a method of blocking the coagulation bath from the outside air except for the passage of the core yarn is also preferable from the viewpoint of concentration control.

Drying process> The core yarn drawn out after the coagulation process is transferred to the next drying process. For drying, normal ventilation drying is sufficient, but in order to improve productivity, heating of drying air, heating with infrared lamps, heating tubes, heating plates, heating rollers, etc. are usually used to accelerate drying. Various means can be used in combination.

The thus obtained filamentous heating element of the present invention has extremely low variation in the amount of resin deposited in the direction of the filament axis because the synthetic resin solution is uniformly adhered thereto. It has air bubbles inside, has excellent mechanical properties such as flexibility, bending resistance, and abrasion resistance, and has a uniform resistance value per unit length of heating wire. It can be used advantageously as a material.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

In addition, the viscosity and durability in the present invention were measured by the following method.

(Viscosity) A sample was collected in a 500 d cylindrical container, and the temperature was 30°C ± 1°C.
The viscosity immediately after production is measured using a BM type rotational viscometer (manufactured by Tokyo Keiki) under the following conditions.

In addition, when measuring, the sample is sufficiently stirred in advance using a propeller mixer or a homomixer.

(Number of cutting and bending) Measurement was performed using an MIT anti-folding tester with an additional load of 0°5 kO1 and a measurement sample length of 7 cm.

(Number of Cutting Wear) Measurements were made using a thread-based abrasion tester with a sample length of 45 cm.

Example 1 Polyester type polyurethane resin (Dainichiseika Kagyo Co., Ltd. H
Carbon black with an average particle size of 40 μm and graphite with an average particle size of 10 μm were suspended in carbon. The synthetic resin solution was adjusted to have a concentration of 7 and 5% by weight, respectively, based on the solution. The viscosity of this solution was 25 voids and the solids content was 26% by weight.

The core yarn is made by spinning polyester at a spinning speed of 3000 m/min, and then subjecting it to a drawing and twisting process using a conventional method.
Low torque by heating plate at 90℃, 150 denier 72
A temporarily twisted yarn with a trilobal cross section of filament was obtained. This yarn was twisted into an egg and used as a core yarn. The fineness of the core yarn was 550 denier, and the density was 1.385 g/CX&.

A preferred manufacturing process of the present invention is shown in FIG.

The synthetic resin solution was sealed in a closed container 10 and stirred, and the synthetic resin solution was transferred from the closed container 10 to the adhesion device 5 using a gear pump 11 having a capacity of 0.017 CG per revolution.

The adhesion device was constructed by installing two V-shaped ceramic yarn guides with a discharge hole diameter of 0.5j1111 in the yarn path direction in opposite directions, with a discharge hole diameter of 0.5j1111 as shown in FIG. It was attached to the core thread. The core thread is roller 2 with a circumferential speed of 8 m/min.
was sent to the deposition device at a constant speed. After passing through the deposition device, the core yarn was subsequently led into a coagulation bath 6 with a length of 1.5 m. The coagulation liquid consisted of methyl ethyl ketone/dimethylformamide/water (weight ratio 30/10/60) and was maintained at 40°C. The excess liquid is removed from the core yarn by a rough drainer 7, and it is passed through a dryer 8 with a length of 1.5 m that circulates hot air at 150°C, and is taken up by a take-up roller 3 at a rate of 8 m/min and wound. It was wound up by machine 9. (In order to check the dry state of the heated yarn, it was re-dried at 100℃ for 15 minutes, but no change in resistance was observed before and after re-drying, confirming that the drying was sufficient. .The obtained filamentous heating element was
When the weight of 40 pieces of each α was measured continuously, the average value was 0.
, 030 g/25 cm, standard deviation 0.0007
8. The CV value obtained by dividing the standard deviation by the average value was 2.6%. Also, when the resistance value of the same thread was measured, the average value was 3.
03, the standard deviation of Ω/25C1ns was 0.112, and the CV value was 3.7%. From this, it was found that the method of the present invention allowed the synthetic resin solution to adhere uniformly in the direction of the fiber axis, so that the variation in the resistance value of the filament heating element became extremely small. Table 1 shows the results of measuring the number of times of cutting and bending and the number of times of cutting and abrasion using this filamentous heating element and a nichrome wire and a commercially available cord heater for comparison. Table 1 shows that the filamentous heating element of the present invention has outstanding durability compared to conventional metal heater wires.

Electrode wire 16 obtained using the thread-like heating element according to FIG.
A skewer-shaped heating element was made using a normal R machine using the thread-like heating element 14 and the polyester thread 18 for adjusting the calorific value as the weft.The purpose of providing a rough insulation coating. Both sides of the fabric were coated with a polyethylene melt. Also, a lead wire 19 that conducts current was connected to the electrode 16 by soldering 20. This fabric-like heating element was sewn to the lining of the vest, and N
When electricity was supplied from an i-Cd battery, there was no local temperature unevenness and it was extremely flexible, which was well received by those who tried it on.

Comparative Example 1 A dryer 8 was installed at a position 15 cm after passing through the adhesion device,
A filamentous heating element 17 was prepared in the same manner as in Example 1 except that the coagulation bath 6 and draining device 7 were removed. After re-drying with hot air at 100℃ for 15 minutes, the resistance value of the winding system decreased to 0.85Ω/25c.
m, decreased by 28%.

Example 2 A filamentous heating element was obtained using a manufacturing process similar to the second white. At this time, the adhesion device used was a device imitating the one shown in Fig. 5, the nipple pore diameter was 0.5 mm, the die discharge hole diameter was 0.8 #φ,
The top surface of the deposition device served as the bottom of the coagulation bath. The length of the coagulation bath is ML.
The coagulation liquid was circulated at a flow rate of 177 L/min. Other conditions were the same as in Example 1. The resistance value of the wound yarn did not change at all before and after re-drying with hot air 100''CX for 15 minutes.

[Effects of the Invention] In the present invention, the variation in the amount of deposited synthetic resin solution is small and the variation in resistance value is small, so when it is made into a product, the temperature can be kept so small that no unevenness is felt at all.
It is highly flexible and has good adhesion between the heating element layer and the core thread, allowing it to bend easily.
This makes it possible to manufacture a thread-like heating element with good operability and high efficiency, which is difficult to peel off due to abrasion, etc., and can be stably used for a long period of time. This makes it possible to provide a heating element that can be knitted and woven and can be applied to various uses such as the clothing field, the clothing field, agriculture, fisheries, and civil engineering fields. hot theory,
It applies to all vehicles such as cars, trains, aircraft, ships, and space rockets.

[Brief explanation of drawings]

This is an example of an adhesion device that can be suitably used. FIG. 6 is a schematic diagram of a fabric-like heating element made by weaving 1 q of thread-like heating elements. 1: Core thread 2.3: Drive system 5: Adhesion device 6: Coagulation bath 7: Drainer 8: Dryer 11: Measuring device

Claims (1)

[Claims] A synthetic resin solution in which conductive fine particles are suspended is attached to the core yarn while being measured by a metering device, and then coagulated in a coagulation bath and dried and fixed to form a conductive layer of a synthetic resin containing conductive fine particles dispersed therein. A method for producing a filamentous heating element characterized by forming it on a core yarn.