JPH0768585A - Thermoplastic heating cylinder - Google Patents

Abstract

PURPOSE:To obtain a long cylindrical body made of thermoplastic resin which is light in weight, excellent in electric conductivity and heat resistance, excellent in dimensional precision, and practically uniform in wall thickness. CONSTITUTION:A thermoplastic resin composition to be used is necessarily within a range of 10<-3>-10<7>OMEGA.cm of volume resistivity. Further, loading flexural temperature measured according to ASTM-D 648 is preferably at least 110 deg.C under a load of 18.6kg/cm<2>. In order to add such a property to the thermoplastic resin composition, an electrically conductive filler is contained. When the composition is used to injection mold a cylindrical body 1, and a voltage is impressed thereto, it can be heated uniformly. Further, when a long cylindrical body 1 wherein a ratio of a length L of the cylindrical body 1 to a diameter D corresponding to a sectional area, i.e., L/D is 2 or over, is used, thermotropic liquid crystalline polyester resin which is excellent in thin wall fluidity is preferably used as the thermoplastic resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating tubular body made of a thermoplastic resin, which is used as a heating element, is lightweight, has good electrical conductivity and heat resistance, and is obtained by injection molding. . The long length here specifically means that the ratio (L / D) of the length (L) and the diameter (D) corresponding to the cross-sectional area (hereinafter, referred to as equivalent diameter) is 2 or more. The equivalent diameter (D) is the outer diameter of a circle in the case of a cylindrical body having a circular cross section, and is the following when the cross section is a cylindrical body having a shape other than a circle such as a triangle or a square. It is represented by a mathematical formula.

[0002]

[Equation 1]

[0003]

2. Description of the Related Art Cylindrical bodies made of synthetic resin, particularly long cylindrical bodies such as rolls and pipes, are used in various fields. Many of these are formed by extrusion. In recent years, there has been an increasing demand for weight reduction as machine parts such as rolls of office machines such as copy machines and printers, and pipes as machine parts, and tubular bodies made of synthetic resin and having high dimensional accuracy are required.

However, in extrusion molding, it is difficult to obtain dimensions such as thickness and diameter with high precision, and it is more appropriate to use the injection molding method. However, the injection molding has the following problems.

That is, in a general injection molding machine, an ejector pin is used to separate a product from a mold, but this operates in the same direction as the moving direction of the mold clamping mechanism of the molding machine.
Therefore, the direction of the central axis of the cylindrical body in the mold must be the same as the moving direction of the mold clamping mechanism.
The size of the injection molding machine is preferably adjusted to the size of the molded product, and in the case of a long tubular body, it may not be possible to release the mold due to the limit of the movement amount of the mold clamping mechanism.

In the case of injection molding a cylindrical body having a large L / D as described above, it is preferable that the direction of the central axis of the cylindrical body is perpendicular to the moving direction of the mold clamping mechanism.

However, in this case, the central axis may be horizontal, vertical, or in the middle thereof, but the mechanism for holding the pillar (male) forming the inner surface of the cylindrical body and the molded product are released from the mold. The direction is complicated and not economical. To do this, the columnar body (male) that forms the inner surface of the tubular body is designed to be detachable from the mold body, and the resin is injection-molded from the gate provided at one end of the mold in the longitudinal direction, An injection molding method is conceivable in which the molded product is released from the mold after it is attached to the pillar, and then the pillar and the injection molded product are separated in a separate process.

As a result, an injection-molded article can be manufactured with a certain degree of dimensional accuracy. However, in this case, since the pillar body and the mold body are not integrated, that is, they are not completely fixed, the pillar body moves due to the pressure of the molten resin flowing at the time of injection to obtain a molded product with good dimensional accuracy. Sometimes I can't.

On the other hand, in recent years, heating rolls have been used in various fields. As the heating roll, for example, a heat fixing roll used in OA equipment such as an electrophotographic copying machine, a facsimile machine, a printer, or laminating or laminating plastic films or plastic films and paper or metal foil, or heating and stretching plastic films A heating roll etc. are mentioned.

These heating rolls are usually made of metal such as aluminum or steel in consideration of thermal conductivity.

However, when such a metal roll is used, there is a problem that the weight of the equipment or the device cannot be reduced. Further, in order to manufacture a metal roll having accuracy, complicated steps such as precision processing and degreasing are required.
Further, in a thermocompression-bonding roll used in an electrophotographic copying machine or the like, its surface is required to have elasticity, but since a metal roll has no elasticity, it is necessary to cover the surface with an elastic body such as fluororesin. there were.

Although it is considered that the above problems can be solved by using a heating roll using a thermoplastic resin having conductivity, as described above, it is difficult to obtain a cylindrical body having high dimensional accuracy. .

[0013]

DISCLOSURE OF THE INVENTION The present invention solves these problems of the prior art, is lightweight, has good conductivity and heat resistance, is excellent in dimensional accuracy, and has a substantially uniform wall thickness. It is an object of the present invention to provide a heating cylinder made of a thermoplastic resin, which is particularly long.

[0014]

Means for Solving the Problems The inventors of the present invention have made various investigations in view of the above situation in a long heating tubular body, and as a result, have solved the above problems and completed the present invention.

That is, according to the present invention, the volume resistivity is 10 ^-3.
The present invention relates to a thermoplastic resin heating tubular body formed by injection molding a thermoplastic resin composition in the range of 10 ⁷ Ω · cm.

The present invention will be described in detail below. In the present invention, the thermoplastic resin used in the thermoplastic resin composition,
There is no particular limitation. Specifically, polyolefin resins such as polyethylene, polypropylene and polybutene, polystyrene resins, polyvinyl chloride resins, aliphatic polyamide resins such as nylon 6 and nylon 66, and aromatic polyamide resins such as polyphthalamide, Polycarbonate resin, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polyoxymethylene resin, polyphenylene ether resin, polyurethane resin, polysulfone resin, polyethersulfone resin, polyphenylene sulfide resin, polyketone resin , Thermotropic liquid crystal polyester resin, polyarylate-based resin, polyimide-based resin, polyamide-imide-based resin, fluorine-based resin and the like. Among these, when molding a long tubular body, a synthetic resin having excellent fluidity is required, and a thermotropic liquid crystal resin having particularly excellent thin-wall fluidity, and more preferably a thermotropic liquid crystal polyester resin is suitable. . If a thermotropic liquid crystal resin is used, a molded product with high dimensional accuracy can be obtained, which is convenient for obtaining a molded product as a machine part.

Two or more kinds of these synthetic resins can be used or a mixture of other polymers such as rubber can be used. At this time, it is preferable to use a compatibilizing agent in order to improve the compatibility of each component. Further, these synthetic resins can be used after being chemically modified.

The thermotropic liquid crystal resin referred to here is
It is a thermoplastic, meltable polymer that exhibits optical anisotropy when melted. As described above, the polymer exhibiting optical anisotropy when melted has a property that the polymer molecular chains have a regular parallel arrangement in the melted state. The properties of the optically anisotropic molten phase can be confirmed by a usual polarization inspection method using a crossed polarizer.

For example, liquid crystalline polyester, liquid crystalline polyester imide and the like, specifically (all) aromatic polyester, polyester amide, polyester carbonate and the like can be mentioned. A thermotropic liquid crystal polyester resin is preferred, and is included in the category of the polyester of the present invention as long as it contains a plurality of ester bonds in the molecule. A more preferred polyester is an aromatic polyester.

In the thermotropic liquid crystal polyester resin preferably used in the present invention, a part of one polymer chain is composed of a polymer segment forming an anisotropic melt phase, and the remaining part is an anisotropic melt phase. Also included are polymers composed of polymer segments that do not form Also, a composite of a plurality of thermotropic liquid crystal polyester resins is included.

As typical examples of the monomer constituting the thermotropic liquid crystal polyester resin, (a) at least one aromatic dicarboxylic acid, (b) at least one aromatic hydroxycarboxylic acid compound, and (c) aromatic At least one kind of diol compound, (d) at least one kind of (d ₁ ) aromatic dithiol, (d ₂ ) aromatic thiophenol, (d ₃ ) aromatic thiolcarboxylic acid compound, (e) aromatic At least one kind of a hydroxyamine and an aromatic diamine compound may be used.

Although these may be configured independently,
Many are (a) and (c), (a) and (d), (a),
(B) and (c), (a), (b) and (e), or (a), (b), (c) and (e), etc. are combined and configured.

As the above-mentioned (a) aromatic dicarboxylic acid type compound, terephthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-triphenyldicarboxylic acid, 2,6-
Naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane-4,
4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether-3,
3'-dicarboxylic acid, diphenoxyethane-3,3'-
Aromatic dicarboxylic acids such as dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, 1,6-naphthalenedicarboxylic acid or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid,
Examples thereof include alkyl, alkoxy or halogen substitution products of the above aromatic dicarboxylic acids such as dimethyl terephthalic acid, ethyl terephthalic acid, methoxy terephthalic acid and ethoxy terephthalic acid.

Examples of the aromatic hydroxycarboxylic acid compound (b) include aromatic hydroxy such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and 6-hydroxy-1-naphthoic acid. Carboxylic acid or 3-methyl-4-hydroxybenzoic acid, 3,5
-Dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl -2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid,
2-chloro-4-hydroxybenzoic acid, 3-chloro-4
-Hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3
-Bromo-4-hydroxybenzoic acid, 6-hydroxy-
Alkyl, alkoxy or halogen substitution of aromatic hydroxycarboxylic acid such as 5-chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid, 6-hydroxy-5,7-dichloro-2-naphthoic acid The body.

As the aromatic diol (c), 4,4 '
-Dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4,4'-dihydroxytriphenyl, hydroquinone, resorcin, 2,6-naphthalenediol, 4,4'-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3 , 3'-Dihydroxydiphenyl ether, 1,6-naphthalenediole, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane and other aromatic diols or chlorohydroquinone Alkyl, alkoxy or halogen substitution products of aromatic diols such as methyl hydroquinone, t-butyl hydroquinone, phenyl hydroquinone, methoxy hydroquinone, phenoxy hydroquinone, 4-chlororesorcinol and 4-methylresorcinol. That.

Examples of (d ₁ ) aromatic dithiol include benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol and 2,7-naphthalene-dithio. -Ru and the like.

Examples of the (d ₂ ) aromatic thiophenol include:
4-mercaptophenol, 3-mercaptophenol
And 6-mercaptophenol and the like.

Examples of (d ₃ ) aromatic thiol carboxylic acid include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid and 7-mercapto-2-naphthoic acid.

(E) Aromatic hydroxyamine and aromatic diamine compounds include 4-aminophenol and N-
Methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine,
N, N'-dimethyl-1,4-phenylenediamine, 3
-Aminophenol, 3-methyl-4-aminophen-
2-chloro-4-aminophenol, 4-amino-
1-naphthol, 4-amino-4'-hydroxydiphenyl, 4-amino-4'-hydroxydiphenylether, 4-amino-4'-hydroxydiphenylmethane,
4-amino-4'-hydroxydiphenyl sulfide,
4,4'-diaminophenyl sulfide (thiodianiline), 4,4 'diaminodiphenyl sulfone, 2,5-
Diaminotoluene, 4,4'-ethylenedianiline,
4,4'-diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4,
4'-diaminodiphenyl ether (oxydianiline) and the like can be mentioned.

The thermotropic liquid crystal polyester resin used in the present invention can be produced from the above-mentioned monomers by various ester forming methods such as a melt acidolysis method and a slurry polymerization method.

As for the molecular weight, that of the thermotropic liquid crystal polyester resin suitable for use in the present invention is about 2
000-200000, preferably about 4000-100
It is 000. The molecular weight can be measured, for example, by measuring the end groups of a compressed film by infrared spectroscopy. Alternatively, GPC, which is a general measurement method involving solution formation, can be used.

Among thermotropic liquid crystal polyester resins obtained from these monomers, aromatic polyesters or copolyesters which are (co) polymers containing the monomer unit represented by the following general formula (1) as an essential component are preferable. The monomer unit preferably contains about 30 mol% or more. More preferably, it contains about 50 mol% or more.

[0033]

[Chemical 1]

A particularly preferred aromatic polyester of the present invention is a copolyester represented by the following formula (2) having repeating units each having a structure derived from three compounds of p-hydroxybenzoic acid, phthalic acid and biphenol. is there. The repeating unit of the structure derived from the biphenol of the copolyester represented by the following formula (2) is
It may also be a copolyester in which some or all of it is substituted with repeating units derived from dihydroxybenzene. Alternatively, it is a copolyester represented by the following formula (3) having repeating units each having a structure derived from two compounds of p-hydroxybenzoic acid and hydroxynaphthalenecarboxylic acid.

[0035]

[Chemical 2]

[0036]

[Chemical 3]

The thermotropic liquid crystal polyester resin used in the present invention may be used alone, or two or more kinds thereof may be mixed and used.

The thermoplastic resin composition used in the present invention must have a volume resistivity in the range of 10 ⁻³ to 10 ⁷ Ω · cm, preferably 10 ⁻¹ to 10 ³ Ω · cm, If it deviates from this range, a heating cylinder having good heat generation cannot be obtained. Further, in order for the obtained heated tubular body to have good heat resistance, the deflection temperature under load measured according to ASTM D648 of the thermoplastic resin composition is 110 ° C. or more under a load of 18.6 kg / cm ^2. Is desirable.

In order to impart such a volume resistivity and a deflection temperature under load to the thermoplastic resin composition, it is necessary to contain a conductive filler. As the conductive filler used in the present invention, fibrous, flake-shaped, and particulate fillers can be used.

As the fibrous material, carbon fiber (PAN
System, pitch type), metal fiber (mild steel, stainless steel, copper and its alloys, aluminum and its alloys, lead), metallized glass fiber (glass fiber coated with nickel, copper, aluminum, silver, etc.), or nickel coat Carbon fibers and the like are included.

As flakes and fibrous substances, various metal powders (iron, copper, aluminum, silver, gold, nickel, zinc, brass, lead, stainless steel) and their flakes,
Various carbon powders (Ketchen black, SRF carbon,
Graphite, activated carbon, etc.), carbon microballoons, glass flakes coated with a metal such as nickel, silver, copper, and the like.

In this case, the preferable conductive filler is a fine particle having a particle diameter of 150 μm or less, a flake shape or a fibrous material having a fiber system of 150 μm or less, and more preferably a Ketchen powder having a particle diameter or a fiber diameter of 100 μm or less. One or more of black, acetylene black, carbon fiber, stainless steel (fiber, powder, flakes) and aluminum (fiber, powder, flakes).

The compounding amount of the conductive filler is preferably 2 to 100 parts by weight with respect to 100 parts by weight of the thermoplastic resin. It is more preferably 5 to 60 parts by weight. If the blending amount is less than 2 parts by weight, the volume resistivity of the molded product will be high, and if it exceeds 100 parts by weight, the production of the resin composition will be difficult and the mechanical properties will be deteriorated.

Furthermore, the thermoplastic resin composition used in the present invention may contain various additives in addition to the conductive filler depending on the purpose. This includes inorganic and organic fillers other than the conductive fillers (glass fiber, talc,
Mica, calcium carbonate, clay, calcium sulfate, magnesium hydroxide, silica, alumina, barium sulfate,
Titanium oxide, zinc oxide, graphite, wood powder, various whiskers), various stabilizers (antioxidants, ultraviolet absorbers, light stabilizers, metal deactivators, etc.), pigments, dyes, plasticizers, oils, lubricants, Examples include nucleating agents, antistatic agents, flame retardants and the like. The compounding amount of the inorganic or organic filler is 90% by weight or less, preferably 80% by weight or less and 1% by weight or more. inorganic,
By blending an organic filler, the heating tubular body of the present invention is preferable because the surface condition is good.

The heating tubular body of the present invention can be obtained by injection molding the above-mentioned thermoplastic resin composition.

FIG. 1 is a perspective view of a cylindrical body which is an example of a heating cylindrical body 1 made of the thermoplastic resin composition of the present invention.
The heating tubular body of the present invention can be formed into a tubular body having a triangular or quadrangular cross section in addition to the cylindrical body, and is basically formed in the same manner as in the case of a cylinder. The size is not particularly limited, and it is possible to mold from a small product having a length (L) of about several centimeters to a large product having a length of more than 1 meter.
It can be molded from thin wall thickness of less than 1 millimeter to thick wall thickness of several centimeters. Also, both ends of the tube may be open or one of them may be closed. Further, it is possible to form a heating cylindrical body having a complicated shape with a collar, a gear or the like at one end or both ends or a body portion.

Next, the injection molding method used in the present invention will be described. FIG. 2 shows a top view and a sectional view of a mold for molding the heated cylindrical body of the present invention.
As shown in FIG. 2, the molten resin fed from the injection unit of the injection molding machine through the sprue 2 and the runner 3 enters the cavity from the bottom of the cylinder through the gate 8 provided at one end in the longitudinal direction of the mold. It flows in and is filled upwards.

A cylinder 6 for forming an inner surface of a cylindrical body is incorporated in the mold. The mold generally has a pair of structures that open to the left and right with the center of the cylindrical body as a boundary (fixed mold 4 and movable mold 5, rarely an intermediate plate may be inserted between them). A recess is formed to form the outside of the body. The stationary mold 4 can also be a movable mold.

It should be noted that traces (parting lines) on the mating surfaces of both molds may remain on the surface of the molded product and spoil the appearance. In order to avoid this, an auxiliary mold (cylindrical structure) for forming the outside of the cylindrical body is incorporated into the fixed mold 4 and the movable mold 5, and after injection, the auxiliary mold is released together with another mold. It is possible to employ a method such as removing the auxiliary mold and the column 6 for forming the inside of the cylindrical body.

The cylinder 6 may be integrally attached to the fixed mold 4 or the movable mold 5, but a mechanism for taking out the molded product must be provided in association with the mold, which complicates the structure. In addition, it takes time to remove the mold, which is not preferable. Therefore,
It is preferable that the column 6 has a structure that can be detached from the mold body. Since the heating cylinder 1 is molded and then removed together with the cylinder 6 by fixing the cylinder 6 to the mold body without allowing the cylinder 6 to be fixed to the mold body, the cylinder 6 is then removed separately. Easy to remove.

However, in this case, it is difficult to firmly fix the column 6 to the mold body, and the column 6 is displaced due to the inflow of the molten resin, so that a molded product with high dimensional accuracy may not be obtained. .

In order to solve this, a ring 7 slidable in the cavity forming the heated cylindrical body 1 inside the molding die is fitted to the column 6 forming the inside of the cylindrical body. Together,
It is preferable to adopt a method of molding while moving the ring by the introduced molten resin.

FIG. 3 is a schematic sectional view showing such a preferable injection molding method of the present invention. This ring 7 has the effect of holding the cylinder 6 in the mold while the molten resin is being introduced, so that the cylinder does not shift and a molded product with good dimensional accuracy can be obtained.
Although FIG. 3 shows an example of a heated cylindrical body, a circular ring is shown, but in the case of a heated cylindrical body other than a cylinder, a ring corresponding to the cross-sectional shape is used. The ring 7 is fitted in the cylinder 6 to such an extent that the molten resin does not leak from the gap where it is fitted.

The fitting position of the ring is not particularly limited,
In order to obtain a molded product with better dimensional accuracy, it is preferable to be as close to the gate 8 as possible. The cylinder 6 can be fitted manually, but it can also be automated using a robot.

It is preferable that the mating ring 7 has a little resistance to the movement of the ring 7 during molding so that the surface of the molded product after molding becomes smooth. Especially when a thermotropic liquid crystal polyester resin is used as the thermoplastic resin,
Especially the tendency is large. If the ring moves easily, flow patterns will appear on the surface. Therefore, if there is a little resistance to the movement of the ring, the ring will be molded while being filled with the resin and the surface will be smooth. This requires that the ring be in intimate contact with the cylinder and / or the mold (fixed and mobile).

The material of the ring 7 is generally resin or metal. As the resin ring, for example, a tubular body (pipe) formed by injection molding is cut and used as a ring because it has a considerable sliding resistance, which is preferable. This is the case where the pipe removed from the mold after molding can fit into the cylinder 6. If the formed tubular body contracts or expands, it cannot be fitted into the column 6 and cannot be used. Thermotropic liquid crystal resin, preferably thermotropic liquid crystal polyester resin, is characterized in that the molding shrinkage is small, and a molded body can be formed exactly according to the dimensions of the mold.
It is preferable to cut a tubular body made of thermotropic liquid crystal resin into a ring.

On the other hand, the metal ring may be the same as the material of the mold body, but it may damage the mold.
It is preferable to use a metal whose hardness is lower than that of the mold. Suitable materials include gun metal, brass, copper, aluminum, duralumin and the like.

Further, the ring for forming a tubular body with a collar needs to have a width larger than that of the collar portion. If the ring width is smaller than the width of the collar portion, the ring moves at the collar portion when the ring is pushed up by the resin and rises, and a tubular body with excellent dimensional accuracy cannot be obtained.

The injection molding machine used in the present invention is also not particularly limited. Screw in-line type, pre-plastic type,
Any type of injection molding machine such as a horizontal type, a vertical type, or a type having a compression mechanism can be used.

In the case of the thermotropic liquid crystal resin, particularly the thermotropic liquid crystal polyester resin, the injection molding conditions are, for example, a resin temperature of 200 to 420 ° C. and a mold temperature of 30.
To 200 ° C., more preferably 60 to 150 ° C., injection pressure 100 to 2000 kg / cm ² , injection speed 20 to 700
It can be appropriately selected from the range of mm / sec.

After the injection molding, the mold is moved and the mold is removed together with the cylinder 6, and the molded product (heated cylindrical body) is taken out.
The heated cylindrical body is obtained by extracting. In addition,
In the case of a thermotropic liquid crystal resin, particularly a thermotropic liquid crystal polyester resin, the dimensional accuracy is good, so that the column 6 can be easily pulled out.

Specific dimensions such as thickness, diameter and length of the long heating cylindrical body formed by this injection molding depend on the shape of the mold which can be manufactured. It is not particularly limited as long as it is, but in the case of using thermotropic liquid crystal resin, particularly thermotropic liquid crystal polyester resin, for example, the thickness is 0.5 mm or more, preferably 1 m.
m or more and 10 cm or less, the equivalent diameter is 3 mm or more, preferably 5 mm or more and 200 mm or less, and the length is 1
The range is 0 mm or more, preferably 20 mm or more and 2 m or less.

[0063]

EXAMPLES The present invention will be described in detail below with reference to examples.

Example 1 As a synthetic resin, a thermotropic liquid crystal polyester resin (phthalic acid / isophthalic acid / 4-hydroxybenzoic acid /
A thermotropic liquid crystal copolyester resin having repeating units each derived from 4,4-dihydroxydiphenyl, each having a molar ratio of 0.75 / 0.
It is 25/3/1. This is 34 when the optical anisotropy was observed using a polarization microscope equipped with a hot stage.
It exhibited optical anisotropy in the molten state at 0 ° C or higher.

70 parts by weight of this thermotropic liquid crystal polyester resin and 30 parts by weight of conductive carbon black were mixed to obtain a thermoplastic resin composition. The volume resistivity of this thermoplastic resin composition is 0.7 Ω · cm, ASTM D 6
Deflection temperature under load measured according to 48 is 18.6 kg /
It was 246 ° C. under a load of cm ² .

Using this thermoplastic resin composition, a mold having a mold thickness of 350 mm as shown in FIG.
Injection molding was performed using a metal ring. After the injection molding, the mold was moved to remove from the mold together with the cylinder 6, the molded product was taken out, and the cylinder 6 was extracted to obtain a heated cylindrical body.

As a result, the length is 300 mm and the inner diameter is 16 m.
A cylindrical injection-molded product (heated tubular body) having a thickness of m and a wall thickness of 2 mm was obtained. The maximum thickness difference of this molded product was 0.1 mm.

An IS-80 injection molding machine (clamping stroke 460 mm) manufactured by Toshiba Machine Co., Ltd. was used as a molding machine, and the molding temperature was 350 ° C., the injection speed was 50 mm / sec, and the mold temperature was 80 ° C.
I did it in. Also, the ring size is 16 mm inside diameter, 1 inside diameter
The ring material was 2 mm, the height was 20 mm, and the ring material was gunmetal (an alloy of 90% by weight of copper and 10% by weight of tin).

When this heated columnar body was energized at a voltage of 100 V, heat generation at 190 ° C. was uniformly observed throughout the columnar body.

[0070]

The heating tubular body of the present invention is lightweight, has good conductivity and heat resistance, is excellent in dimensional accuracy, and has a substantially uniform wall thickness. For this reason, in many fields such as heat fixing rollers of OA equipment such as electrophotographic copying machines, facsimiles, printers, heating rollers for various processing machines and electric appliances, drying rollers, and various heating pipes. Used. In particular, thermotropic liquid crystal resins, preferably thermotropic liquid crystal polyester resins, have good molding fluidity, high dimensional accuracy, and extremely high heat resistance. Therefore, heating cylinders made of these resins are generally used at high temperatures. It is especially suitable as a heating roller or heating pipe that may be exposed to.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a heating tubular body of the present invention.

2A and 2B are a top view and a cross-sectional view of a mold used for manufacturing the heating tubular body of the present invention.

FIG. 3 is a schematic cross-sectional view showing an injection molding method for a heating tubular body of the present invention.

[Explanation of symbols]

1: Heating cylindrical body (heating cylindrical body) 2: Sprue 3:
Runner, 4: fixed type, 5: movable type, 6: cylinder, 7: ring, 8: gate, 9: groove, 10: spring.

Claims (3)

[Claims] 1. A heating cylinder made of a thermoplastic resin, which is obtained by molding a thermoplastic resin composition having a volume resistivity in the range of 10 ⁻³ to 10 ⁷ Ω · cm by injection molding. 2. ASTM D of the thermoplastic resin composition
Deflection temperature under load measured according to 648 is 18.6k.
The heating tubular body made of a thermoplastic resin according to claim 1, which has a temperature of 110 ° C. or higher under a load of g / cm ² . 3. The heating tubular body made of a thermoplastic resin according to claim 1, wherein the thermoplastic synthetic resin is a thermotropic liquid crystal polyester resin.