JPS63270868A - 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 [Industrial Application Field] The present invention relates to a method for producing an electrically heated filamentous heating element that is highly flexible and durable for long-term use.

[Prior Art] Flexible heating wires made of thin metal wires have been used to keep equipment warm or heated, but electric blankets, electric blankets, etc.
It has become widely used in consumer products such as electric carpets, and due to its convenience, there is a trend that products will become more diversified in the future.

Conventionally, resistors made of thin metal wires such as stainless steel wires and nichrome wires have been used for these heating elements, but if the above products are required to be flexible, flexible Used materials include those in which ultra-thin resistance wire is wound in a spiral shape around a polyester core thread, and those in which carbon is fixed to a fabric using a resin binder.

However, none of these can meet 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 publication No. 470. This increases the flexibility of the heating element by providing a rubber or plastic layer containing conductive fine particles around the filamentous heating element. However, the manufacturing method is that of electric wire manufacturing, and uses large-scale equipment consisting of a heating and melting section of conductive rubber or plastic, a heat-insulating piping section, and a melt-coating section. Two pores with a diameter of 11 nIR or less are provided in the melt-coated portion for introducing and extracting the core yarn, and the temperature is maintained at a high temperature that allows the rubber or plastic to have fluidity. therefore,
The operation of passing the core thread 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 clothing, innerwear, gloves, shoes, etc., and requires a high degree of bending durability 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. 39-37689M discloses a method in which a resin containing conductive fine particles is prepared as a solution, applied to a core thread, 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 above-mentioned melt coating method. However, in the heating element heated by this method, the solution cannot be applied uniformly, so that temperature unevenness occurs when electricity is applied, and there is even a possibility of causing burns or fire. therefore,
This is not recognized as an appropriate manufacturing method for filamentous heating elements.

In addition, for example, Japanese Patent Application Laid-Open No. 51-109321 is an attempt to improve the flexibility of thread-like heating elements. This is a filament-like heating element in which a nylon conjugate filament is softened by heating or swollen by a swelling agent to fix carbon particles to the surface layer of the filament. This heating element has too high a resistance value per length and is not suitable for use as a heating element. Furthermore, it is difficult to uniformly fix the carbon particles, and therefore the resistance value varies widely, making it impossible to industrially and stably manufacture the required resistance value.

[Problems to be Solved by the Invention] The present invention solves these conventional problems, and provides a resistor IC with small variations, high flexibility, good adhesion between the conductive layer and the core yarn, and bendable, The object of the present invention is to provide a method for stably producing a high-quality filamentous heating element that is difficult to peel off due to wear or the like and can be stably used for a long period of time.

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a filamentous heating element of the present invention has the following configuration. That is, a synthetic resin solution in which conductive fine particles are suspended is metered by a measuring device and supplied to the core yarn from each discharge hole of a plurality of yarn guides provided so as to adhere from different directions. This is a method for manufacturing a filamentous heating element, which is characterized in that a conductive layer of a synthetic resin containing conductive fine particles dispersed therein is formed on the core yarn by drying and fixing the conductive particles.

The most important point of the present invention is that the synthetic resin solution is supplied to the core yarn from each discharge hole of a plurality of yarn guides provided so as to be applied from different directions.

First, in the present invention, a thread guide is used as the attachment device. As will be described later, among the above-mentioned inventions, measured adhesion is essential to the present invention in order to make the resistance value uniform during long contact. For example, although it is possible to reliably coat the wire using a device similar to the above-mentioned electric wire manufacturing method, the thread guiding properties of the core yarn are poor. Furthermore, in the method of applying a liquid in the form of a spray, uneven adhesion occurs. The first problem when uneven adhesion occurs is
This is when the product is as shown in the figure. FIG. 1 is a diagram of a fabric-like heating element product obtained using a filamentous heating element.

The electrical system of the fabric-like heating element 15 is composed of a lead wire 19 that supplies electricity from the outside, an electrode wire 16 that is a warp that supplies electricity to each thread-like heating element 8 in parallel, and the thread-like heating element 8 . If there is uneven coating on the filamentous heating element, electricity may not be supplied to some of the filamentous heating elements, or
Failure to do so may result in contact failure, resulting in uneven product temperature or fire.

The present invention has improved this point, and has a uniform resistance value per length of J stiffness, and the core yarn is completely covered.

A filamentous heating element can be installed with good operability.

A detailed explanation will be given below.

The discharge holes of each of the plurality of yarn guides must be installed so that the core yarn is completely covered with the solution. "From different directions" means that the arrangement is such that this purpose is achieved. The same meaning applies even when the yarn path is bent by the yarn path guide.

The core yarn coated with the solution is then sent to the drying process, but the core yarn near the yarn guide is rotated in the yarn axis direction due to the torque of the core yarn, heat shrinkage during untwisting and drying process, etc. There are many cases where the driver is running while driving. At this time, if a plurality of thread guides are installed apart from each other, complete coverage cannot be achieved due to uneven rotation. In addition, except in special cases such as overcoating with a solution of a different composition, complete coverage is possible with just two thread guides, so installing thread guides is not practical in terms of complete coverage and equipment simplification. It is preferable that the solution is applied to the core thread by means of two thread guides that face each other and are close to each other. FIG. 2 shows an example of the arrangement.

The upper and lower thread guides 1 and 2 of the intrusion are substantially opposed to each other, and the distance (L) between the guides is 20 seconds or less.

In order for the adhesion device to continuously adhere a certain amount of the synthetic resin solution to the core thread, it is necessary that the distance from the discharge hole of the synthetic resin solution to the time when the core thread leaves the adhesion device is short. A core thread guide with a discharge hole is used. In addition, since the thread path of the core yarn does not move within the attachment device, there is a thread guide groove such as a V-shaped groove, a U-shaped groove, or a flat groove, and a discharge hole is bored in the recessed part of the thread guide groove. Preferably, a trail guide is used. 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. (a> is a V-shaped groove, (b) is a diagram of a U-shaped groove, and (C) is a diagram of a flat groove.

The material for the core yarn used in the present invention may be a synthetic fiber that maintains stable performance over a long period of time within the temperature range and has good adhesion to the conductive layer.

Thermoplastic synthetic fibers such as polyamides, polyesters, and polyolefins are non-hygroscopic and chemical resistant, and are less susceptible to thermal deterioration in the above temperature range, and will melt and break if localized abnormal heating occurs. This is preferable because it has the fuse function of Furthermore, if heat-resistant fibers such as aromatic polyamide, polybenzimidazole, polyphenylene triazole, polyoxadiazole, polyimide, and thermosetting resin fibers are used, the usable temperature range can be increased. Further, it is preferable because it has the advantage that the product life can be significantly extended.

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. It is possible to achieve a smooth surface, a non-flat yarn cross section, and when made into a yarn, it has 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 purpose. Specifically, spun yarns, burnt spun yarns, flat yarns, bulky processed yarns, twisted yarns, double yarns, eggs, etc., fluid-processed highly entangled yarns, taslan yarns, bimetal composite fibers of synthetic fibers, etc. Examples include asymmetric cooling systems.

It is also preferable to treat the core yarn in advance with a substance that has high affinity for both the conductive fine particle-containing synthetic resin and the core yarn.

The synthetic resin containing conductive fine particles dispersed therein used in the present invention is preferably used, but is not particularly limited, as long as it is thermally stable and has excellent adhesiveness, bending resistance, abrasion resistance, etc. Examples of the resin to be obtained include polyurethane resins, acrylic resins, butyral resins, and particularly flexible ones are preferably selected.

As the conductive fine particles used in the present invention, for example,
Carbon particles and metal particles are representative examples. For example, ordinary carbon black can be used as the carbon particles, and the particle size is 1 to 1.
A material having a diameter of 500 mμ is preferable, and a material having a diameter of 20 to 200 mμ is more preferably used.

Furthermore, graphite can also be used as the 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, but in particular, phosphorous graphite or flaky graphite with a size of 5 to 100 μm A size of 50 μm is preferably used. 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. For example, in order to obtain a resistance value suitable for a heating element, carbon particles are used in an amount of 5 to 25% by weight, preferably 7 to 15% by weight in the resin solution.

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, in the case of the above-mentioned combination, the resistance value of 07m can be set to 1q between 1 and 100.

The volume resistivity of the resin at this time depends on the thickness of the thread, but is approximately 0.01 to 10 Ω·cm. 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.

In the present invention, in order to make the filamentous heating element flexible and durable against repeated folding and abrasion, bubbles can be generated in the conductive synthetic resin by the following means.

This can be achieved by mixing a blowing agent such as azobisisobutyronitrile (AIBN) into the suspension, coating with a low boiling point solvent such as methyl ethyl ketone, and then conventional solvent evaporation ( This can be achieved by a method of drying under conditions such that the ambient temperature is higher than the temperature at which solvent vapor is taken into the heat generating layer.

In addition, when foaming is performed using the above-mentioned AIBN, for example, AIBN@ is mixed in advance with a resin dissolved in dimethylformamide, and if the resin is dried at 150° C., foaming can be achieved by thermal decomposition.

There is no limit to the amount of air bubbles mixed in, and if there is a small amount, the flexibility of the filamentous heating element obtained will be at the level of the material, and if there is a large number, the flexibility will increase, but if there is too many, the mechanical strength and surface smoothness will decrease. . Therefore, it is preferable to determine it empirically or experimentally from the physical properties of each material constituting the filamentous heating element.

The heating layer of the filamentous heating element of the present invention may be a single layer, but may be laminated in multiple layers for the purpose of adjusting the electrical resistance value, smoothing the surface, etc. The number of layers to be laminated is not particularly limited, and the purpose can usually be achieved by laminating about 1 to 3 times. At this time, the concentration of carbon particles dispersed in each heating layer can be changed, for example, in order to improve the smoothness of the surface of the filamentous heating element. For example, the content may be 12% by weight, 10% by weight from the innermost layer, 5% by weight from the outermost layer, etc.

Naturally, it is also possible to carry out the measurement deposition and drying steps in one step, but it is preferable to carry out the deposition in one step in terms of equipment.

An example of the method for manufacturing the filamentous heating element of the present invention is shown below.

Preparation process> Preparation of core yarn: Prepare thread without knots.

Preparation of a 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. At this time, it is preferable to adjust the viscosity of the synthetic resin solution to 2 to 200 poise in terms of uniform adhesion and discharge efficiency of the metering device. 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 saving energy in the drying step after adhesion and workability in the suspending and dissolving steps.

The synthetic resin solution is sealed in a closed container to prevent evaporation of the solvent. Further, it is desirable to stir the synthetic resin solution in order to maintain the homogeneity of the solution.

Measuring and Adhesion Step> The synthetic resin solution in which conductive fine particles are suspended is transferred from the sealed container to a measuring device through piping while being stirred. 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 measuring device and making it adhere to the core yarn, the amount of adhesion in the axial direction of the strands can be reduced. It is possible to make the variation extremely small.

Specifically, the weight variation Cv (%) in the yarn axis direction was set to 6.
By doing so, the heat generation performance of the product can be made to the same level as products made of conventional thin metal wires.

The measured synthetic resin solution is further transferred through the piping to the coating device, and is applied from the periphery to the core yarn running from bottom to top.

In order to reduce variations in the amount of coating, it is preferable to feed the core yarn to the coating device at a constant speed. For this purpose, it is preferable to use a method in which the yarn is fed by a row before the adhering device and after the drying step described below, and then taken off. In order to adhere with appropriate tension, it is preferable to apply tension using front and rear rollers.

Drying process> The core yarn pulled out from the weighing and adhering process is sent to a drying device located above the coating device.

Drying can be done by normal ventilation drying, but in order to improve productivity, various commonly used means to accelerate drying can be used in combination, such as heating the drying air or heating with an infrared lamp. .

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.Also, since the filamentous heating element employs a dry fixation method, the filamentous heating element It has air bubbles inside, is highly flexible, has excellent mechanical properties such as bending resistance and abrasion resistance, and has a uniform resistance value per unit length of the heating wire, making it a suitable heating material for various heating element products. It can be used advantageously as

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

In addition, each measurement value in this invention was based on the following method.

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

Note that, prior to measurement, the sample is sufficiently stirred using a propeller mixer or a homomixer.

(Number of cutting and bending times) Measurement was performed using an MIT anti-folding tester with an additional load of 0.5 kg and a measurement sample length of 7 cm.

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

Example 1 Polyester type polyurethane resin (Dainichiseika Kagyo Co., Ltd.)
After uniformly dissolving methyl ethyl ketone and dimethyl formamide in a mixed solution (weight ratio 80:20) to a concentration of 13.5% by weight, carbon black with an average particle size of 40 mμ and graphite with an average particle size of 10 μm were dissolved. The synthetic resin solutions were adjusted to have a concentration of 8.5 and 6% by weight, respectively, based on the carbon suspension solution. The viscosity of this solution is 2
The solid content was 1 poise and 26 poise. For the core yarn, polyester was spun at a spinning speed of 3,000 m/min, and then drawn and pre-twisted using a conventional method.Then, the torque was reduced using a hot plate at 190°C to create a 150-denier, 72-filament trilobal cross-section pre-twisted yarn. Obtained. Twist three of these threads together,
It was used as a core yarn of 510 denier.

The synthetic resin solution was sealed in a sealed container, stirred, and rotated once at zero.
．． A gear pump in a 0.17 cc container was used to transfer the synthetic resin solution from the closed container to the deposition apparatus. The adhesion device is the third
Using a model similar to that shown in Figure (b), two U-shaped ceramic yarn guides with a discharge hole diameter Q of 5 mm and a concave radius of 0.5 m were installed in opposite directions at an interval of 5 mm as shown in Figure 2. It was attached to a core thread running at a discharge rate of 10.133 cc/min. The core yarn was fed to the adhesion device at a constant speed by a roller with a circumferential speed of 1 m/min. The thread tension just before the attachment device was 70Q. The solvent was evaporated using a heating cylinder with a length of 1.25 m installed at a position 15α behind the deposition device. At this time, by setting the inner wall temperature of the heating cylinder to 200°C, the evaporation of the solvent is accelerated and foaming is promoted.
In addition, the solidification of the synthetic resin solution is accelerated so that air bubbles are incorporated into the heat generating layer. In this way, the synthetic fiber containing conductive fine particles dispersed therein was fixed to the core thread, and then taken off by a roller at a circumferential speed of 1 m/min.

(The average value of 40 weights ω of 25 cm each in the filament axis direction was continuously measured, and the average value was 0.0327/
25 ca, standard deviation 0.00060, and the Cv value obtained by dividing the standard deviation by the average value was 1.9%. In addition, when the resistance value of the same thread was measured, the average value was 2.76Ω/25cm.
, standard deviation 0.105, CVVB 28%. From this, it was found that the method of the present invention allowed the synthetic resin solution to adhere uniformly in the yarn axis direction, and thus the variation in the resistance value of the filamentous heating element became extremely small. When the side surface of this filamentous heating element was observed over a 10 m distance, no exposed core yarn was observed.

A multi-layer heating element obtained using the filamentous heating element will be explained with reference to FIG. The fabric-like heating element 15 shown in the figure uses an electrode wire 16 made of tin-plated copper wire and a polyester thread 17 for the warp, and the thread-like heating element 8 and a polyester thread 18 for adjusting the amount of heat generated for the weft. A fabric-like heating element was made using an ordinary loom. Furthermore, both sides of the fabric were coated with a polyethylene melt for the purpose of insulating coating.

Further, a lead wire 19 through which current is passed was connected to the electrode wire 16 by soldering 20. When electricity was supplied from a Ni-Cd battery to this fabric-like heating element sewn onto the lining of a vest, it was found to be extremely flexible with no local temperature unevenness, and was well received by those who tried it on.

Comparative Example 1 A filamentous heating element was obtained in the same manner as in Example 1 except that the number of yarn guides was one and the discharge rate was 0.267 CC/min.

When we observed the side surface of this filament heating element over 10 m, we found that the longest part in the filament axis direction was 5 cm long, and had a width Q, 'i
There were three core thread exposed parts of nn.

[Effects of the Invention] According to the present invention, it is possible to manufacture a filamentous heating element that has extremely small temperature variations as a product, has good flexibility, bending resistance, etc., and can be stably used for a long period of time, using simple equipment and with good operability. can. This allows for weaving and knitting, which can be used in the clothing field, embedded materials field, etc.
This provides a heating element that can be used in various fields such as agriculture, fisheries, and civil engineering. It can be applied to all kinds of vehicles such as cars, trains, aircraft, ships, and space rockets.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a fabric-like heating element obtained by weaving a thread-like heating element. FIG. 2 is a diagram showing an example of a preferred arrangement of the yarn path guide of the present invention. FIG. 3 is an example of a deposition device used in the present invention. Patent applicant Toshi Co., Ltd. Figure 1 [1 (1)) (C) Figure 3 Figure Z

Claims (1)

[Claims] A synthetic resin solution in which conductive fine particles are suspended is metered by a metering device and supplied to the core yarn from each discharge hole of a plurality of yarn guides provided so as to adhere from different directions, and then dried. A method for producing a filamentous heating element, which comprises forming a conductive layer of a synthetic resin which is fixed and contains conductive fine particles dispersed thereon on the core yarn.