JPH07235371A - Complex tubing body resistance heat emission type - Google Patents

Abstract

PURPOSE:To provide a resistance type heat emitting tube which emits high temp. heat in a short time with a low power consumption and which has an excellent durability etc. CONSTITUTION:A resistance type heat emitting composite tube is formed from a tubing having a volume resistivity of 10<-3> thru 10<3>OMEGA.cm and a thermosetting resin through a weaving process of carbon fibers 2 and is coated with a fluoric resin. This composite tube 1 is used in many fields as a heat emitting roller of high performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance exothermic composite tubular body and is used as a roll-shaped heating member for a copying machine and various other devices.

[0002]

2. Description of the Related Art In a copying machine or the like, a fixing means for fixing a toner image transferred on paper or the like is generally a heating roller system which passes between heated rolls. A metal tube such as an aluminum tube is used for the heating roll, and a heater is built in the tube for heating. There is also a fixing means called a surf method in which a plastic belt is used as a fixing belt and heating is performed by heating the belt from inside the belt with a ceramic heater or the like. Further, carbon black, metal powder, or the like is used as a conductive material, which is mixed with a synthetic resin (for example, polyimide) to form a film-shaped cylindrical body. Since heat is generated when a voltage is applied to this, it has been attempted to process it into a roller shape or a belt shape and directly heat it by passing an electric current.

[0003]

The greatest drawback of the above heating roller system is that it takes a long time to reach the heat fixing temperature of a toner image transferred onto paper or the like. Therefore, it consumes a large amount of power and has a long heating time. Therefore, it is performed by electrically heating even when it is not used. Therefore, the power consumption due to this is further added, resulting in further power consumption. Further, there are drawbacks such that it is difficult to reduce the weight and size of the device itself.

In the surf system, a fixing means using a belt is used, and the mechanism is inevitably complicated because the belt is driven. Further, when the belt is made of metal, it also has a defect as seen in the heating roll system, and when it is made of plastic, it has a defect that mechanical troubles easily occur due to thermal deterioration.

In an attempt to obtain a resistance heating roller or belt by mixing a conductive material such as carbon black with a synthetic resin and forming it into a tube shape, it is extremely difficult to obtain the temperature required for heat fixing the toner and the like. Even if it is obtained, the result is that the mechanical properties are greatly deteriorated and it is practically impossible to use.

[0006]

That is, the present invention achieves the above object by providing the following means. According to the invention of claim 1, a volume resistance value of 10 is obtained by weaving carbon fibers.
^-3 to 10 ³ Ωcm of a tubular body and a thermosetting resin are compounded, which is a resistance heating composite tubular body, and the invention of claim 2 is a resistance heating system in which the tubular body is coated with a fluororesin. It is characterized by being a sex composite tubular body.

Further, the tubular body is woven by a round braided structure, the carbon fiber is a carbonized fiber of polyacrylonitrile fiber, and the thermosetting resin is phenol type, epoxy type, ester type and It is a resin selected from the group of imide-based thermosetting resins, and the coating of the fluororesin is also characterized in that it is a tubular body made of a preformed fluororesin coated. .

In the present invention, as is generally known, the carbon fiber is an organic polymer fiber which is heated and fired at about 1000 ° C. or higher. Here, the organic polymer fiber is
An atom whose main chain is bound by carbon and the others burn with carbon,
Since it is a polymer substance to which an organic group or the like is bound, it does not matter whether it is natural or synthetic fiber. Fibers commonly known as petroleum pitch, cellulosic fibers,
Acrylonitrile fibers can be exemplified.

As a more preferable carbon fiber, an acrylonitrile-based fiber is used, and by this, easiness of weaving in a tubular body by a woven structure, more efficient heat generation, more toughness, etc. are exhibited.

Generally, in the carbon fiber, the higher the firing temperature is, the remaining carbon is changed into a structure close to that of graphite. This is firing at about 2000 ° C. or higher, and this is also called graphite fiber, but since the tensile strength is physically reduced, the weavability of the tubular body of the present invention tends to be poor, and the firing temperature is too high. Carbon fibers having a high tensile strength, ie, a low tensile strength, are not desirable.
From the viewpoint of this firing temperature, carbon fibers fired at a temperature of about 1500 ° C. or lower (also called carbonized fibers) are preferable.

Generally, carbon fibers have electrical conductivity, and the present invention has one of the characteristics of effectively utilizing this original electrical conductivity, but it is very excellent in electrical conductivity. Is not desirable. This is because the heat generation temperature is low and it takes a long time to reach the predetermined temperature. The electrical conductivity improves as the firing temperature rises,
It is said that the volume resistance value is about 10 ⁻¹ to 10 ⁻⁴ Ωcm. However, in practical use of carbon fiber, various conditions are added and deformed, whereby the resistance value changes.

Although the thickness of the carbon fiber is not particularly limited, it is generally about 4 to 10 μm in diameter of a single fiber, but when actually used as a tubular fabric, a multifilament shape is preferable. In the case of this multifilament, the number of single fibers bundled is not limited, but is about 50.
0 to 30,000, preferably 1000 to 10,
000 can be illustrated.

The carbon fibers need to be woven into a specific form, namely a tubular body. Here, weaving means weaving continuous carbon fibers (in practice using multifilaments), in particular by the texture of the fabric. Therefore, the object of the present invention cannot be achieved with a tubular body made of another tissue such as a knitted fabric or a non-woven tissue. That is, when the knitting structure itself is used as a roll, sufficient strength to firmly fix and maintain roundness cannot be obtained, and the back surface of the roll lacks smoothness. In the case of the non-woven structure, as in the case of the knitted structure, the circularity retention as a roll is lacking, and it is difficult to obtain a predetermined temperature as a resistance heating element.

The woven structure for forming the tubular body will be described. The woven structure refers to a form of a thread (multifilament) woven into a tubular shape, but the form is not particularly limited in the present invention. For example, weaving with the same structure as the braid can be mentioned. That is, this design is generally a woven form in which the yarns run obliquely with respect to the length direction and these intersect at an angle to each other. Based on this form, when woven in a tubular shape, the threads run in the shape of left and right threads and intersect each other. FIG. 1 shows this state. FIG. 1 shows 100 carbon fibers with a single fiber diameter of 5 μm.
1 is a perspective view of a tubular body 1 woven by a loom for a round braid with 0 bundled yarns 2. Although the weave is densely woven with a porosity of substantially 0, it is enlarged for the sake of explanation and is illustrated in a state in which it is perforated. This organization corresponds to FIG. 3 described later.

There are no particular restrictions on the way the threads are crossed left and right. For example, an organization according to the method shown in FIG. 2 can be mentioned. Of course, you are not limited to this,
It can be exemplified as a preferable one. 2 to 5 are woven by the carbon fiber yarn (multifilament) 3 in each of the structures of FIG. 2 of one set, FIG. 3 of two sets, FIG. 4 of three sets, and FIG. It is the expansion top view which expanded the formed tubular body.

The shape (length, diameter, wall thickness) of the tubular body is successively determined depending on the purpose and application, but the length is about 1
For example, the diameter is about 0 to 500 mm, the diameter (outer) is about 5 to 30 mm, and the wall thickness is about 0.1 to 2 mm.

In the case of actually weaving into a tubular body, generally, in many cases, a machine which is a slightly improved machine is used as the basis of the machine for the machine. There are two types of this group machine, a normal group machine and a high-speed group machine, and they are used properly on a case-by-case basis.

In the case of weaving with carbon fibers, for example, in order to control the electrical conductivity (volume resistance), other semiconductive inorganic fibers, insulating glass fibers, and composite with thermosetting resin are used. In order to improve the above properties, heat resistant fibers such as aromatic polyamide may be mixed and woven.

Not all of the tubular bodies obtained by weaving carbon fibers thus obtained achieve the object of the present invention, and in particular, among them, the volume resistance value is 10 ⁻³ to 10 ³ Ωc.
It is limited to tubular bodies in the range of m, preferably 10 ⁻² to 10 ² Ωcm. If the volume resistance value is less than 10 ⁻³ Ωcm, it is difficult to obtain a desired predetermined heating temperature, and even if it is obtained, a large amount of power is consumed. On the other hand, 10 ³ Ωc
When it exceeds m, temperature unevenness is likely to occur in the tubular body for the same reason as the above-mentioned case of less than 10 ⁻³ Ωcm, and the heating temperature is not uniform throughout.

The volume resistance value is a value obtained by calculating an electric circuit as shown in FIG. 6, applying a voltage to the tubular body by an AC power source, measuring the voltage on the resistor side, and calculating. FIG. 6 is an electric circuit diagram showing a state in which the tubular body 10 is connected to the terminal 11 of the measuring circuit 4 and measurement is performed. The measuring circuit 4 includes an AC power supply 5 for supplying a voltage to the tubular body 10,
A voltmeter 6 for measuring the voltage V, a resistor 7 having an electric resistance of 1Ω for adjusting the voltage applied to the tubular body 10, and a voltmeter 8 for measuring the voltage V ₂ are connected to each other. . On the other hand, the tubular body 10 whose volume resistance value is to be measured is connected like the measuring circuit 4. At this time, the electrode circuit 12 for connection with the terminals 11 is provided over the entire outer circumference of both ends of the tubular body 10. To provide. This electrode circuit 12 is made of silver conductive paste (Silvest P-17 manufactured by Tokuriki Kagaku Kenkyusho).
31-EC), a width of 5 mm and a thickness of 20 μm are fixed to the carbon fibers of the tubular body 10 so as to be conductive. The electrode circuit 12 and the circuit terminal 11 are connected with screws.

When the above measuring circuit 4 is set, a voltage is applied by the AC power source 5, the applied voltage V is measured by the voltmeter 6, and at the same time, the voltage V ₂ on the side of the resistor 7 is measured by the voltmeter. Measure with 8. Before connecting the tubular body 10, its length (l) and cross-sectional area (S) are measured in advance. The difference between the measured voltages of V and V ₂ is calculated, and the voltage V ₁ of the tubular body 10 is known. This voltage value V ₁ is put into the calculation formula of the number I to calculate the volume resistance value (Ω.c) of the tubular body 10.
m) Calculate ρ. Here, R and I respectively represent the resistance value (Ω) and the current value (A) of the tubular body 10. The volume resistance value ρ
Is a value obtained by changing the applied voltage and averaging the volume resistance values ρ _n for each applied voltage.

[0022]

[Equation 1]

The thermosetting resin is an insoluble and infusible resin as is generally known, and examples thereof include phenol-based, ester-based, epoxy-based, imide-based and melamine-based resins.
Examples thereof include diallyl phthalate-based and silicon-based thermosetting resins. These resins are relatively low molecular weight substances before curing (in liquid or solid form, which are precursors of the resin)
Shows fluidity (plasticity) at room temperature or heating,
It undergoes a chemical change (curing reaction) by the action of a curing agent, a catalyst, or heat to change into an insoluble and infusible resin. Although any thermosetting resin can be used in the present invention depending on the purpose and application, the composite property with a woven tubular body made of carbon fiber, heat resistance, firm roundness retention, smoothness of the tubular body surface, etc. Considering this, phenol-based, ester-based, epoxy-based, and imide-based thermosetting resins are preferable. Among the preferable conditions described above, an imide thermosetting resin is mentioned as a more preferable composite material for applications requiring higher heat resistance, for example, for fixing rollers for toner images in copying machines and the like.

The above-mentioned phenolic, epoxy, ester, and imide thermosetting resins will be described in more detail as follows.

The phenolic thermosetting resin is generally obtained by reacting an aromatic alcohol such as phenol with formaldehyde in the presence of a catalyst. Here, the structure of the resin differs by changing the reaction molar ratio of both, but in any case, the resin changes to an insoluble and infusible resin. That is, when the formaldehyde is reacted excessively, an alkali catalyst is made to exist. In this case, a thermoplastic starch syrup-like polymer is first obtained, which is generally called a resol. On the contrary, when the phenol is excessively reacted,
The reaction is carried out in the presence of an acid catalyst, in which case a solid polymer called novolak is obtained, which is a thermoplastic polymer. Both the resol and the novolak are said to be precursor polymers of the phenolic thermoplastic resin. The insoluble and infusible resin can be changed by heating at a higher temperature in the case of resol and by adding amine as a catalyst in the case of novolac and heating. In addition, cresol, alkylphenol, etc. can be used instead of phenol.

The epoxy thermosetting resin is a polyfunctional epoxy compound having two or more glycidyl groups (which has a low molecular weight and a high molecular weight) and an organic compound having two or more amino groups and hydroxyl groups (low molecular weight). Or a high molecular weight) as a curing agent. And, depending on the combination of the two, ordinary heat resistance (120 to 130 ° C) and high heat resistance (1
70 to 200 ° C. or higher), but high heat resistance is preferable in the present invention. This high heat resistant grade is, for example, a phenol novolac type epoxy prepolymer having 3 or more glycidyl groups as an epoxy compound, if necessary an organic solvent, and an organic diamine or a phenol novolac prepolymer as a curing agent. Mix and add to this a tertiary amine as a catalyst. This is a viscous liquid as a whole and is in an uncured state, that is, a precursor polymer state, and when heated, it changes into an insoluble and infusible high heat resistant epoxy resin. In addition, triglycidyl metaaminophenol or tetraglycidyl diaminodiphenylmethane as an epoxy compound (low molecular weight), and an organic diamine (for example, diaminodiphenylmethane or diaminodiphenylsulfone) as a curing agent are mixed in an equivalent amount, and a tertiary amine is added thereto. It is added as a catalyst. This mixture is uncured, that is, a precursor, and when it is heated, it is converted into an insoluble and infusible heat resistant epoxy resin.

The ester-based thermosetting resin is generally an alkyd-based resin (branched structure) obtained from an aromatic dicarboxylic acid and a trivalent or divalent aliphatic polyhydric alcohol, and an alkyd-based resin such as maleic acid or fumaric acid. An unsaturated polyester obtained from a saturated dibasic acid and a dihydric alcohol is dissolved in a crosslinking agent such as styrene, and this is reacted with a reaction initiator to form a thermosetting polyester (crosslinked structure) 2
There are two types. The latter is preferred in the present invention.

The imide-based thermosetting resin is a generally known thermosetting resin containing an imide group as a repeating unit, and examples thereof include condensation polymerization type and addition polymerization type depending on the polymerization type. Among the resins, there is also a thermoplastic type polyimide, but this is because the composite with the tubular body is not performed smoothly,
Excluded from the invention.

Here, the polycondensation type is, for example, an equimolar amount of an organic tetracarboxylic dianhydride or an organic tricarboxylic anhydride and an organic diamine in an organic polar solvent such as N-methylpyrrolidone or dimethylformamide at low temperature. The polyamic acid (also referred to as polyamic acid) obtained by reacting at about room temperature or lower is further heated to 200 ° C. or higher, preferably 30.
Obtained by heating at 0-400 ° C. Examples of the organic tetracarboxylic dianhydride include pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, bezophenonetetracarboxylic dianhydride and the like. Examples of organic tricarboxylic acid anhydrides include phenyl tricarboxylic acid anhydride. On the other hand, as the organic diamine, 4,4'-diaminodiphenyl ether, 4,4 '
Examples thereof include -diaminodiphenylmethane, P-phenylenediamine, 4,4'-diaminobenzophenone and the like, but the invention is not limited thereto. Further, the physical properties and the like of the obtained resin are changed depending on the combination of these starting materials, but it is not limited thereto.

A typical example of the addition polymerization type is a resin obtained by an equimolar reaction of a bismaleimide and the above-mentioned organic diamine in an organic solvent, and the diamine is added to the double bond of the bismaleimide. It becomes a polymer. Therefore, unlike the polycondensation type, by-products such as water are not generated at all, which is preferable in some cases.

The thermosetting resin is basically used alone, but in some cases, it may be appropriately mixed and used. In addition, the resin may be mixed with a powdery conductive material, for example, an inorganic powder such as carbon black, silver powder, and stannic oxide powder, which is one of the more preferable embodiments in some cases.

Next, a composite of a carbon fiber woven in a tubular shape (hereinafter referred to as a tubular body for convenience) and a thermosetting resin will be described. It is desirable for this composite to reinforce the tubular body and to form a roll having a smooth surface without losing its circularity for a long period of time to any roll pressure, and therefore, the present invention In particular, this is achieved by compounding a thermosetting resin. By compounding the resin, strength equal to or higher than that of a metal pipe such as an aluminum pipe can be obtained, and therefore, it is not necessary to dare to internally support a metal or plastic core rod in the tubular body.

Considering the significance of the above-mentioned combination, the composite ratio of the tubular body and the resin has a greater effect, but conversely deviates from the above-mentioned predetermined volume resistance value to the larger one. As a result, the desired heat generation cannot be obtained. Therefore, there is a reasonable upper limit. Further, it is desirable that the lower limit is an amount sufficient to eliminate fine irregularities due to the weaving yarn found on at least the surface of the tubular body and to make the surface smooth.
Considering such conditions, the resin amount per unit surface area (cm ² ) of the tubular body is about 0.01 to 0.1 g, preferably 0.015 to 0.05 g / cm ^2. It can be illustrated as a ratio.

There is no particular limitation on the method of compounding, and various commonly used methods can be applied. For example, as various methods, the tubular body is immersed in the liquid of the precursor of the thermosetting resin as it is, and then cured by heating. Further, the liquid material is sprayed onto the surface of the tubular body to be applied, and finally it is cured by heating. Furthermore, a method of coating the surface of the tubular body with a coater, followed by heating and curing, or a combination of these various methods can be mentioned.

In any of these methods, it is more desirable that the circumference of each carbon fiber constituting the tubular body is coated with the precursor as much as possible. The method for this is, for example, using a low-viscosity precursor liquid, dipping for a longer period of time, or repeating dipping, spraying, coating and pre-drying not only once but several times, and finally with a higher viscosity. It is desirable to coat the surface with the precursor liquid and finish the surface with high precision.

Furthermore, in the same manner as in the case where the carbon fibers are bundled into the multifilaments, or after the bundles are sized (pasted), they are passed through while dipping in a low-viscosity solution of the precursor. , Pre-dry (uncured). It can also be used to weave into tubular bodies. Such a method not only has the effect of thinly coating the circumference of each carbon fiber, but also has the effect of tightly bundling it as a multifilament, resulting in easy tubular weaving and compaction, and thermosetting. Since the adhesiveness with the functional resin is also improved, this sizing method performed in advance can be mentioned as one of the more preferable embodiments.

The precursor described above is a precursor before the conversion to the thermosetting resin, as will be apparent from the detailed description of each thermosetting resin, and can be freely deformed and processed.
In many cases, it is liquid and reacts to some extent from the raw material stage to form a prepolymer, or in the case of polyimide, an unclosed polyamic acid. In any case, the reaction is further advanced by heating or the like at the end, and finally the resin becomes insoluble and infusible.

The carbon fiber may be subjected to a surface treatment which is generally carried out in order to improve the adhesiveness with the thermosetting resin. This surface treatment is often an oxidation method.
This oxidation method includes oxidation by a chemical solution such as nitric acid and potassium permanganate, or liquid phase oxidation by electrolysis and oxidation in a solution such as casein soda and sulfuric acid, and gas phase oxidation performed by oxygen, ozone, air and the like. . Above all, electrolytic oxidation is advantageous from the viewpoint of process control because the oxidation time is short. Incidentally, it does not matter at which stage (raw yarn, tubular body, etc.) this surface treatment is carried out.

The exothermic temperature obtained on the surface of the resistance exothermic composite tubular body of the present invention is about 100 to 250 ° C., and it can be obtained at a low voltage in a short time (within about 60 seconds).

Next, the invention described in claim 2 will be described. The present invention is an exothermic composite tubular body obtained by further coating the exothermic composite tubular body according to claim 1 with a fluororesin. Therefore, the fluororesin to be coated will be described here. In particular, since the fluorine-based resin is coated, in some cases, a better surface can be obtained than the composite tubular body of the invention of claim 1 coated with a thermosetting resin, and the mold releasability is excellent. The thermocompression bonding of all objects is performed smoothly. Furthermore, it is also excellent in heat resistance, chemical resistance, electrical characteristics (especially the minimum dielectric constant in each resin), and has good coverage. Silicone rubber or a resin thereof is, for example, a material corresponding to the fluorine-based resin, but this silicone-based material is not preferable because the covering property is not good. Here, in some cases, depending on the type of thermosetting resin to be composited, the surface property of the composite tubular body is unsatisfactory for the intended use, or the releasability is not sufficient even in the pressure bonding with a certain object. It is bad, and it is difficult to separate from the surface of the composite tubular body.

The method for coating the fluorine-based resin is not particularly limited. For example, as seen in the baking coating method,
The surface of the tubular body is coated with a fluororesin that has been made into a paint and baked to form a coating film, or it is molded into a tubular shape in advance corresponding to the tubular body, and the tubular body is inserted into the tubular body. As described above, the temperature is lower than the melting point. At that time, heat shrinkage occurs, and a method such as tight fastening coating can be presented.

The above-mentioned baking coating method will be described more specifically. A fluorine resin powder is dissolved or emulsified and dispersed in an organic solvent or water to form a coating material. This coating solution is applied by a method such as spraying, dipping, or roll coating with a roll coater. Then, the solvent and water are removed by evaporation in advance, and finally the resin is heated to above the melting point (baking temperature) and melted to form a coating film. The thickness of the coating film here is preferably as thin as possible, and may be about 100 μm or less. If the required thickness is not reached, the same operation may be repeated multiple times until the required thickness is reached.

Here, as the fluorine-based resin to be used as a paint, for example, polyvinylidene fluoride (baking temperature of about 260
℃ ~ 280 ℃, polyvinyl fluoride (calcination temperature about 240
℃), polychlorinated ethylene trifluoride (firing temperature about 250
To 260 ° C.), homopolymers such as ethylene-chlorotrifluoroethylene (calcining temperature of about 260 to 270 ° C.), ethylene-tetrafluoroethylene (calcining temperature of about 280 to 350 ° C.), and further fluoroolefins. And a plurality of hydrocarbon vinyl ether copolymers having functional groups (hydrophilic groups such as hydroxyl group, alkoxy group, carboxyl group and alkylcarboxyl group) (for example, Lumiflon manufactured by Asahi Glass, Fluoronate manufactured by Dainippon Ink and Chemicals, Central Glass) Cellular coat etc.). Since this copolymer is hydrophilic, it can be exemplified as having better emulsion dispersibility with water and a lower baking temperature. In addition, perfluorocyclopolymer (for example, CYTOP manufactured by Asahi Glass, Teflon A manufactured by DuPont)
Since F) dissolves in a perfluoro solvent, it can be applied as a solution.

When a preformed tubular body is used, it can be tightened by utilizing the heat shrinkage force. Therefore, when preforming, it is preferable to stretch the tube a little to the extent of shrinkage. Is. Regarding the thickness, it is preferable that the thickness be as thin as possible, as in the case of the baking coating method,
In such a case as well, it is possible to exemplify about 100 μm or less. The inner diameter is preferably slightly larger than the outer shape of the tubular body so that it can be inserted (inserted) while contacting the tubular body.
Clearance is not preferred. The fluorine-based resin used here can be exemplified as described above,
Other than that, copolymer polymers such as tetrafluoroethylene-hexafluoropropylene and tetrafluoroethylene-perfluoroalkyl vinyl ether can be exemplified. Among these polymers, the crystalline polymer is more preferable than the non-crystalline polymer. This is because the heat-shrinking force exerts a larger fastening force on the tubular body. This coating method has an advantage in that it can reliably and accurately coat at a lower temperature and in a shorter time than the baking coating method.

The fluorine-based resin may be used alone or in combination, but other third component may be mixed. For example, as in the case of the thermosetting resin, a conductive inorganic powder such as carbon black can be used. In general, a resin has a heat insulating property, so that the mixing of carbon black may be preferable in the sense of increasing the thermal conductivity. (Especially when the coating is thick)

What kind of fluorine resin should be selected is
It is determined in consideration of the type of the composite tubular body, particularly the heat resistant temperature of the composite thermosetting resin, and the coating method. From the coating method, coating with a fluorine-based resin that has been formed into a tubular shape in advance has a wide range of selection. This is a low temperature (glass transition level)
This is because, unlike the coating method, a high coating temperature is not required because there is no need to worry about deterioration of the thermosetting resin compounded at that temperature. Since the fluororesin has its own heat resistant temperature, it is advisable to select the most suitable one in consideration of the purpose and application. For example, in a field requiring heat resistance such as a copying machine, a perfluoro-based homopolymer or copolymer (200 ° C. or higher) can be exemplified.

[0047]

According to the present invention, continuous carbon fibers are used and are woven into a tubular shape with a woven structure, and a tubular body having a predetermined volume resistance value is combined with a thermosetting resin. As a result, heat generated at an extremely high temperature can be obtained only by applying a low voltage for one hour, and the tubular body forms a tough tube like a metal tube such as an aluminum tube.

The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0049]

【Example】

Example 1 First, a tubular body was produced by the following method. That is, polyacrylonitrile was fired as carbon fiber to prepare Torayca T900-1K (multifilament yarn having a single fiber diameter of about 5 μm and a bundle number of 1000 fibers, manufactured by Toray).
This was woven into a tubular shape with the double-set structure shown in FIG. 1 by a normal set machine for round punching braid which was slightly improved for carbon fiber. The obtained tubular body was a perfect circular tube, which was extremely hard and had no openings. The tube length was 23.0 cm, the outer diameter was 1.0 cm, and the inner diameter was 0.90 cm. Therefore, the wall thickness was 0.05 cm and the cross-sectional area was 0.1492 cm ² .
Hereinafter, this is referred to as a tubular body (S).

Silver conductive paste (Silvest P-1731-manufactured by Tokuriki Kagaku Kenkyusho) was applied to the entire circumference of both ends of the tubular body (S).
EC) was applied by screen printing so as to have a width of 5 mm and a thickness of 20 μm, and heated at 120 ° C. for 20 minutes to form the silver electrode circuit 12. This was incorporated into the measurement circuit 4 shown in FIG. 6, the terminal 11 and the electrode circuit 12 were connected by screws, and the volume resistance value was calculated by the next voltage measurement.

First, the AC power source is set to 5 to 4V, 6
Each voltage of V and 8V was applied. The voltage V ₂ applied between the 1Ω resistors 7 for each applied voltage was read by the voltmeter 8. Table 1 shows the above voltage measurement results and the volume resistance value (Ω · cm) obtained by the number I.
It can be understood that the volume resistance value within a predetermined range is obtained.

[0052]

[Table 1]

Next, a thermosetting polyimide was compounded with the tubular body (S) to evaluate its performance as a resistance heating composite tubular body as follows.

First, as precursors of the polyimide to be composited, equivalent amounts of pyromellitic dianhydride and 4,4'-diaminodiphenylmethane were dissolved in N-methylpyrrolidone and polymerized at 20 ° C. Obtained solution viscosity 800cps
The polyamic acid solution of was prepared.

Next, the entire portion of the tubular body (S) masked with the portion of the silver electrode circuit 12 was immersed in the polyamic acid solution and slowly pulled up vertically. This operation was repeated three times in one direction, inverted and three times in that direction, and air-dried for a while.
Then, it took 30 minutes to reach 200 ° C. in a hot air drier, the temperature was gradually raised, further raised to 350 ° C., and heated at that temperature for 60 minutes. The polyamic acid was completely ring-closed and imidized to form a thermosetting polyimide, which was bonded and composited to the tubular body (S). The whole is extremely hard,
The woven carbon fiber had no surface irregularities and was smooth, and was ready for use as a roll.
Although a pressure of 100 kg / cm ² was applied to the composite tubular body, it maintained a perfect circle without any eccentricity. It weighs 4.8g (about 4 for an aluminum tube of the same size)
It was 0 g) and was lightweight. Hereinafter, this is referred to as a composite tubular body (W).

Finally, the resistance heating temperature of the composite tubular body (W) was measured. The measuring method was exactly the same as in the case of the tubular body (S), and was connected to the terminal 11 of the measuring circuit 4 of FIG. The temperature due to heat generation is based on the thermal video system (Model / T
The reading results by VS-2600TE) are summarized in Table 1. The temperature displayed on the system is described over the entire length so that temperature variations can also be checked. Since the read temperature is the average value of the temperatures described in the full length and the temperature error was ± 1 ° C, it was confirmed that there was no temperature unevenness. The applied voltage is 8.4V and 1
The applied temperature is set to 0.5 V, the application time is varied from 20 to 60 seconds, and the heat generation temperature in each case is measured. The results are shown in Table 1.

Example 2 The trading card multifilament yarn used in Example 1 was
Phenol novolac type epoxy (Epilot 152 manufactured by Yuka Shell Epoxy Co., Ltd.) was dissolved in trichlene, and an equivalent amount of 4,4′-diaminodiphenylmethane was added thereto and uniformly mixed to obtain a solution viscosity of 100 cps.
The trichlene was removed by evaporation while slowly passing through the liquid at room temperature. The obtained yarn was thinly coated with an epoxy precursor, and the whole was bound to form a united yarn form. With this coating yarn,
A tubular body was woven in the same manner as in Example 1. This tubular body is harder and more densely woven than the tubular body (S), and has a length of 23.0 cm, an outer diameter of 1.0 cm, and an inner diameter of 0.90c.
m, wall thickness 0.05 cm, cross-sectional area 0.1492 cm
It was ² . Then, in the same manner as in Example 1, the voltage was measured and the volume resistance value was calculated and summarized in Table 2. Hereinafter, this is referred to as a tubular body (2S).

[0058]

[Table 2]

Next, in order to form a thermosetting epoxy resin in the tubular body (2S), it was first dissolved in the above Epicoat 152 xylene, to which an equivalent amount of 4,4'-diaminodiphenylmethane was added and mixed uniformly. Solution viscosity 90 obtained by
A 0 cps solution was prepared. Using this solution, a dip coating was carried out in the same manner as in Example 1, and after air drying for a while,
The mixture was heated at 80 ° C. for 2 hours and at 160 ° C. for 2 hours with a hot air dryer to be completely heat-cured to be bonded and composited. The surface of the obtained composite tubular body was smooth, and the whole was extremely hard and formed a tough perfect circle. 100kg for this composite tubular body
/ Cm ² was applied, but there was no eccentricity at all. Hereinafter, this is referred to as a composite tubular body (2W).

Next, the resistance heating temperature of the composite tubular body (2 W) was measured. The measurement is performed in the same manner as the composite tubular body (W),
It was connected to the terminal 11 of the measurement circuit 4 in FIG. 6, and an alternating voltage was applied to heat it. As for the temperature due to heat generation, the results read by the thermal video system are summarized in Table 2 as described above. The temperature was an average value of the temperatures read over the entire length, and the error was ± 1.2 ° C, and it was confirmed that there was no temperature unevenness. The applied voltage is 8.4V and 10.5.
V, the application time was varied from 20 to 60 seconds, and the heat generation temperature in each case was measured.

Example 3 The following tube was prepared as a fluororesin for coating. That is, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) powder was added to 380 to
It was formed into a tube through an annular die by an extruder heated to 430 ° C. The resulting tube had an inner diameter of 1.1 mm and a wall thickness of 30 μm. Next, this PFA tube was used as the polyimide composite tubular body (W) obtained in Example 1.
(Outer diameter 1.0 mm) and inserted uniformly at 150 ° C. for 10 minutes. This heating causes the tube to shrink,
Tightened tightly and covered the whole.

Then, the obtained PFA-coated composite tubular body was connected to the measuring circuit 4 in the same manner as in Example 1 to apply a voltage,
The exothermic temperature was measured by a thermal video system. As a result, the temperature was 60 seconds after the application of 8.4 V and the temperature was 1
The temperature after 60 seconds from application of 42 ° C. and 10.5 V is 192.
It was 5 ° C. The results show that the coating has no effect on the temperature.

Furthermore, 10.5 was added to the PFA-coated composite tubular body.
After applying a voltage of V for 1 minute, the toner powder scattered on the copy paper was rotated by a roll to check the fixing and releasability.
As a result, the scattered toner powder was completely fused to the paper and no phenomenon such that the toner adhered to the surface of the composite tubular body was observed.

[0064]

The resistance heating composite tubular body according to the present invention comprises:
Compared with the conventional heating means, the following remarkable effects are exhibited. First, to uniformly generate heat in a wide range from low temperature to high temperature in a short time with a low applied voltage. Further, since it has extremely high heat resistance and toughness, it can withstand repeated use for a long time, and further, it is lightweight and has a large heat capacity even with a small tubular body. Therefore, by using this tubular body as a heating roller in various devices, it is possible to develop a lightweight, compact device with high performance and low power consumption. Further, since the surface of the tubular body has good releasability, it is preferably used in a copying machine or the like.

[Brief description of drawings]

FIG. 1 is a perspective view of a round braid woven tubular body made of carbon fiber.

FIG. 2 is a development view of a tubular body formed of a set of woven fabrics.

FIG. 3 is a development view of a tubular body formed of two sets of woven tissue.

FIG. 4 is a development view of a tubular body having a set of three woven fabrics.

FIG. 5 is a development view of a tubular body made of a two-piece braided woven fabric.

FIG. 6 is a circuit diagram for measuring a volume resistance value.

[Explanation of symbols]

 1 ... Tubular body 2 ... Carbon fiber yarn (1000 multifilaments) 3 ... Carbon fiber yarn 4 ... Measuring circuit 5 ... AC power supply 6 ... Voltmeter 7 ... Resistor (1Ω) 8 ... Voltmeter 9 ... Tubular body voltage (calculation) 10 ... Tubular body 11 ... Terminal 12 ... Electrode circuit

Claims (7)

[Claims] 1. A volume resistance value 10 formed by weaving carbon fibers.
^-3 to 10 ³ Ωcm tubular body and thermosetting resin are compounded, resistance heat-generating composite tubular body. 2. A volume resistance value 10 formed by weaving carbon fibers.
A resistance exothermic composite tubular body comprising a resistance exothermic composite tubular body composed of a tubular body of ^-3 to 10 < ³ > [Omega] cm and a thermosetting resin coated with a fluorine-based resin. 3. The resistance heat-generating composite tubular body according to claim 1, wherein the tubular body is woven with a round braided tissue. 4. The resistance heat-generating composite tubular body according to claim 1, wherein the carbon fiber is a carbonized fiber of polyacrylonitrile fiber. 5. The resistance heat-generating composite tubular body according to claim 1, wherein the thermosetting resin is a resin selected from the group consisting of phenolic, epoxy, ester and imide thermosetting resins. . 6. The resistance heat-generating composite tubular body according to claim 2, wherein the fluorine-based resin coating is formed by coating a tubular body made of a fluorine-based resin that has been molded in advance. 7. A tubular body is woven by a round braided structure, carbon fibers are carbonized fibers of polyacrylonitrile fiber, and thermosetting resin is phenol-based, epoxy-based, ester-based or imide-based heat. The resistance heating composite tube according to claim 2, which is a resin selected from the group of curable resins, and the coating of the fluorine-based resin is a tubular body made of a fluorine-based resin that has been molded in advance. body.