JPH1171008A - Conveyor belts and belt conveyors - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily prevent a belt from being grimed without contact, by placing a photo-catalyst layer which is found with photo-catalyst particles with a resin bonding agent on one side or both sides of the belt, and irradiating one side or both sides of a running belt by ultraviolet rays. SOLUTION: An endless belt 2 provided with a photo-catalyst layer (a layer made by bonding anatase type titanium oxide particles bonded with a feuororesin finder) is spanned between a driving wheel 11 and a belt wheel 12 via snap belt wheels 13, 13 and a tension device 14. An ultraviolet irradiating device 15 using a black light, a fluorescent light, a halogen lamp, a mercury lamp is arranged such that it can irradiate the photo-catalyst layer of the belt 2. When the running belt 2 passes through where the ultraviolet irradiating device 15 is placed, photo-catalyst particles in the photo-catalyst layer are activated, fungi suspended in the air touching with the active photo-catalyst particle is sterilized, and multiplication of the fungi is prevented. Therefore, generation of the fungi on the belt can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

The present invention relates to a conveyor belt and a belt conveyor, and is particularly useful for conveying food.

[0002]

2. Description of the Related Art In a belt conveyor, molds and other stains may be generated on the belt depending on the transported material and the transport environment (temperature, humidity, etc.). Such generation of dirt is unsanitary, and it is conventionally known to run the belt while passing it through a contact cleaner in order to prevent the generation of such dirt.

[0003]

However, when the belt conveyor is stopped for a long period of time and then restarted, the adhesive force of the stains such as mold and the like adhered during the long-term suspension of operation is strong, and the above-mentioned contact type cleaner is used. It is difficult to remove mold and the like even if the belt passes through a belt, and if the contact pressure between the belt and the cleaner is increased so as to enable the removal, an overload will be caused and obstacles to the conveyor drive will be avoided. Absent. by the way,
When semiconductor fine particles of titanium oxide or the like are irradiated with light having a wavelength having energy equal to or greater than the band gap, electrons are generated in the conductive band and holes are generated in the valence band by photoexcitation. An adjacent substance can be decomposed by an oxidizing action due to electron transfer between the adjacent substance. Therefore, it is known to perform antifouling, sterilization, and the like using this (for example, Japanese Patent Application Laid-Open No. 6-315614).
JP-A-7-171408, JP-A-7-26571
No. 4, JP-A-8-1010).

SUMMARY OF THE INVENTION An object of the present invention is to provide a belt conveyor which uses a photocatalyst and which can easily prevent the occurrence of dirt on a belt in a non-contact manner. A further object of the invention is
An object of the present invention is to provide a conveyor belt capable of easily preventing the occurrence of dirt on the belt by the above-mentioned non-contact type while stably maintaining the mechanical strength and the laminated state of the belt from the activation action of the photocatalyst.

[0005]

In the belt conveyor according to the present invention, a photocatalyst layer in which photocatalyst fine particles are bound with a resin binder is provided on one or both sides of the belt, and one or both sides of the running belt are irradiated with ultraviolet rays. The configuration is characterized by providing means. The conveyor belt according to the present invention is a photocatalyst layer in which photocatalyst fine particles are bound with a fluororesin binder,
A structure characterized by being provided on one or both surfaces of a fluororesin belt body, or a photocatalyst layer in which photocatalyst fine particles are bound with a fluororesin binder, and a fiber core material impregnated with fluororesin and applied. A configuration characterized by being provided on one or both surfaces of a belt body, or an antifouling film in which a photocatalyst layer in which photocatalyst fine particles are bound with a fluororesin binder is provided on one surface of a fluororesin layer or a fluororesin-impregnated fiber base material Wherein the fluororesin layer or the fluororesin-impregnated fiber base material is bonded to one or both surfaces of the belt body.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a belt conveyor according to the present invention. In FIG. 1, 11
Denotes a driving belt wheel, and 12 denotes a belt wheel. Reference numeral 2 denotes an endless belt provided with a photocatalyst layer (a layer in which photocatalyst fine particles are bound with a binder) on one or both sides,
It is suspended over a driving belt wheel 11 and a belt wheel 12. Reference numerals 13 and 13 denote snap belt wheels, and 14 denotes a dancer-type tensioning device. Reference numeral 15 denotes an ultraviolet irradiation device which is arranged so as to irradiate the photocatalyst layer of the belt 2, and can use a black light, a fluorescent lamp, a halogen lamp, a mercury lamp, or the like. In FIG. 1, the belt is driven by the driving of a driving belt car. When the running belt passes through the location where the ultraviolet irradiation device is provided, the photocatalyst fine particles of the photocatalyst layer are activated, and the air in contact with the active photocatalyst fine particles in the air. Suspended fungi are sterilized and their propagation is suppressed.
Thus, the occurrence of mold on the belt can be prevented. During the long-term suspension of the conveyor, especially in a humid atmosphere such as the transportation of frozen foods, the occurrence of mold on the belt is inevitable.However, by re-driving the belt conveyor, the adhered mold is irradiated with ultraviolet light, The microbes are sterilized by the activation of the photocatalyst fine particles and peeled off, and the peeled mold is dropped and removed while the belt is running below. Accordingly, since the belt can be stained in a non-contact manner, the belt can be kept hygienic while ensuring smooth running of the conveyor without occurrence of abnormalities such as overload. It is preferable to provide a scraper that comes into light contact with the belt to promote the reliable removal of the mold.

FIGS. 2A and 2B show cross sections of a sheet used for one conveyor belt according to the present invention.
Photocatalyst layer 2 in which photocatalyst fine particles are bound with a fluororesin binder
1 is provided integrally on one or both sides of a belt body 22 made of fluororesin. In the sheet shown in FIG. 2B, a dispersion of fluororesin powder and photocatalyst fine particles is applied to a casting carrier, and the applied layer is dried and fired to form a photocatalyst layer 21. The dispersion of the inorganic additive and the fluororesin powder is applied on the photocatalyst layer layer a plurality of times, dried and fired to form the belt body 22, and the dispersion of the fluororesin powder and the photocatalyst fine particles is further applied. The coating layer can be manufactured by drying and firing to form the photocatalyst layer 21. (A) of FIG.
In the sheet shown in (1), a dispersion of fluororesin powder and photocatalyst fine particles is applied to a casting carrier,
The coating layer is dried and fired to form the photocatalyst layer 21. Further, a dispersion of the inorganic additive and the fluororesin powder is applied on the photocatalyst layer layer a plurality of times, dried and fired to form the belt body 22. By forming, or applying the dispersion of the inorganic additive and the fluororesin powder to the casting carrier a plurality of times, drying and firing to form the belt body 22, the photocatalyst fine particles and the fluororesin powder are further formed. Is formed on the belt body by applying, drying and firing to form the photocatalyst layer 21. In the dispersion medium of the dispersion,
Water can be used. The application of the dispersion includes a method of dipping in the dispersion and pulling up, a method of spraying the dispersion, and a method of dispersing the dispersion.
A method of applying a brush with a brush, a method of casting a dispersion, and a method of applying a dispersion with a roll coater can be used.

The sheets shown in FIGS. 2A and 2B are as follows.
At least one of the molded sheet for the belt main body 22 and the molded sheet for the photocatalyst layer 21 may be unfired and laminated and pressed, and then fired to integrate them. In this case, the molded sheet is formed by compressing a raw material obtained by blending an inorganic additive or photocatalyst fine particles into a molding powder of a fluororesin into a block, firing, and cutting into a sheet. Or after aging a mixture of fluororesin powder, lubricating oil, photocatalyst fine particles or inorganic additive, extruding, further rolling, etc. to form a sheet to remove the lubricating oil ( Extrusion / rolling / unfired method) or by removing the lubricating oil and firing (called extrusion / rolling / firing method). For example, the belt body can be obtained by compression molding / firing method. A molding sheet for the photocatalyst layer by extrusion, rolling and unsintering methods, laminating and pressing both sheets, then firing and integrating them, forming the belt body Sheet and photocatalyst layer Molded sheet - produced by both extrusion-rolling-green method bets, both sheet - a were stacked under pressure, and then fired to a method in which integration of both may be used. In the sheet used for one conveyor belt according to the present invention, a chemically stable and hardly decomposable fluororesin is used as a binder for the photocatalyst layer. Regardless, the photocatalyst fine particles can be stably supported,
Since the belt is made of fluororesin, the fusion interface between the photocatalyst layer and the belt body can be stably maintained. Therefore, the mechanical strength and the laminated state of the belt can be stably maintained from the activation action of the photocatalyst.

FIGS. 3 (a) and 3 (b) show a cross section of a sheet used for a conveyor belt different from the above according to the present invention, in which photocatalyst fine particles are bound with a fluororesin binder. The photocatalyst layer 21 is provided on one or both sides of the belt main body 220 in which the fiber core material 222 is impregnated and coated with the fluororesin 221. The fiber core material 222 is used for stabilizing the size with respect to a temperature change. As the fiber core material 222, a material having a smaller coefficient of thermal expansion than a fluororesin is used, and an inorganic fiber cloth such as glass cloth or metal is preferable. The sheets shown in FIGS. 3A and 3B are a method of dipping the fiber core material 222 in a dispersion of a fluororesin powder and pulling it up, a method of spraying the dispersion, and a method of spraying the dispersion. A method of applying a brush with a brush, a method of casting the dispersion, a method of coating with a roll coater, and the like, coating and impregnating with a fluororesin, drying and baking are repeated several times to obtain a fluororesin having a predetermined thickness. Impregnated fiber core material 22
0, and a dispersion of a fluororesin powder and photocatalyst fine particles is applied to one or both surfaces by the same coating method as described above, followed by drying and firing to form a photocatalyst layer 21 having a predetermined thickness. . When using a fiber core material 222 to which a sizing agent is attached, such as a glass fiber cloth, it is preferable to volatilize and remove the sizing agent at substantially the firing temperature of the fluororesin.

In the sheet used for another conveyor belt according to the present invention, the fluororesin layer of the fluororesin-impregnated fiber core material 220 is stably supported, despite the active action of the photocatalyst particles. 221 and photocatalyst layer 2
1 can be assured, and a fluororesin layer 221 is interposed between the fiber core material 222 and the photocatalyst layer 21 so that the fiber core material 222 and the photocatalyst fine particles (photocatalyst layer 2
Since the contact with (1) is eliminated, the fiber core material 222 can also be stably held. Therefore, the mechanical strength and the laminated state of the belt can be stably maintained from the activation action of the photocatalyst.

The thickness of the photocatalyst layer 21 of the sheet shown in FIGS. 2 and 3 is usually 5 to 50 μm, and the thickness of the fluororesin layers 22 and 221 is normally 50 to 2000 μm.
The thickness of the fiber core material 222 is usually 30 to 1000 μm. The fluororesin powder is made of polytetrafluoroethylene (calcination temperature is about 390 ° C., melting point is 327
° C), tetrafluoroethylene perfluoroalkylvinyl ether copolymer (calcination temperature is about 390 ° C, melting point is 310 ° C), tetrafluoroethylene-hexafluoropropylene copolymer (calcination temperature is about 350 ° C).
° C. The melting point is 260 ° C.) and the like, and their particle size is usually 0.2 to 0.3 μm. The concentration of the dispersion is set in accordance with factors such as a coating method and is usually 40 to 60% by weight. As the photocatalyst fine particles, it is preferable to use anatase type titanium oxide fine particles exhibiting excellent photocatalytic activity. Further, in order to enhance the activity of the photocatalyst fine particles, an alkali metal ion can be supported. The particle diameter of the photocatalyst fine particles is usually 0.007 to 0.2.
μm. The weight ratio of anatase type titanium oxide fine particles / fluororesin in the photocatalyst layer is 1/9 to 6/4, preferably 3/7 to 5/5. If it is less than 1/9, the amount of the photocatalyst fine particles is too small to obtain a satisfactory antifouling effect, and if it is 6/4, the amount of the fluorocarbon resin as the binder is too small and it becomes difficult to carry the photocatalyst fine particles satisfactorily. An antistatic agent or a reinforcing material can be added to the fluororesin layers 22 and 221 containing no photocatalyst fine particles as needed. For example, carbon, graphite, bronze, molybdenum disulfide, glass fiber chops and the like can be added.

FIG. 4 shows a sheet used for another conveyor belt according to the present invention. In FIG. 4, A is an antifouling film in which a photocatalyst layer 21 in which photocatalyst fine particles are bound with a fluororesin binder is provided on one surface of a fluororesin layer 22, B is a normal conveyor belt, and antifouling film A is Sputter etching on the surface of the fluororesin layer 22,
The adhesive 3 is applied to the conveyor belt B with an easy adhesion treatment such as sodium treatment.

FIG. 5 shows a sheet used for another conveyor belt according to the present invention. In FIG. 5, A is a photocatalyst layer 21 in which photocatalyst fine particles are bound with a fluororesin binder, provided on one surface of a fluororesin-impregnated fiber core material 220 (222 is a fiber core material, 221 is a coated / impregnated fluororesin). Dirty film B is a normal conveyor belt. The outer surface of the fluororesin layer 221 of the antifouling film A is subjected to easy adhesion processing such as sputter etching and corona treatment, and is adhered to the conveyor belt B with an adhesive 3. is there. As the adhesive 3, a hot-melt adhesive, an adhesive or the like can be used. Examples of the ordinary conveyor belt B include, for example,
Metal belts such as stainless steel and iron, rubber belts such as silicone rubber, nitrile rubber, and natural rubber, polyvinyl chloride,
Plastic belts such as polyethylene and polystyrene can be used. In the sheet shown in FIG. 4 or FIG. 5 used for the conveyor belt according to the present invention, the adhesive interface between the antifouling film A and the conveyor belt B is separated from the photocatalyst layer 21 by the fluororesin layer 22 or 221. Therefore, the adhesive interface can be stably protected from the activating action of the photocatalyst, and despite the presence of the adhesive interface, the mechanical strength and the lamination state of the belt can be stabilized similarly to the sheets shown in FIGS. 2 and 3 above. Can be maintained.

The above-mentioned sheets are joined endlessly to form a conveyor belt, and the joining can be performed by a heat-sealing overlap method, a butt method, a laminating method, or the like. For heat fusion, use an adhesive film of direct fusion or a heat-fusible fluororesin (tetrafluoroethylene perfluoroalkylvinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, etc.) When the fluororesin of the sheet is polytetrafluoroethylene, the latter is used for the heat sealing.
In the case where the fluororesin is a tetrafluoroethylene perfluoroalkylvinyl ether copolymer or a tetrafluoroethylene-hexafluoropropylene copolymer, the former direct contact is preferred. The conditions (pressure, temperature, time, etc.) of this heat fusion are set according to the thickness of the sheet. For example, when the total thickness is approximately 130 μm, the temperature is 380 ° C., the pressure is 1 kg / cm ² , and the time is 90 seconds.

In the belt conveyor according to the present invention,
Even if fungi propagate during long-term operation, the hygiene can be preserved by sterilizing the propagated fungi by the oxidizing action of the photocatalytic fine particles upon restart. Thus, the belt conveyor according to the present invention is particularly useful as a conveyor for conveying food products, for example, for conveying frozen foods, and for baking hamburgers and confectionery.

[0016]

According to the belt conveyor according to the present invention, as described above, even if fungi grow during long-term operation, the propagated fungi can be sterilized by the oxidizing action of the photocatalytic fine particles upon restart. This is clear from the comparison between the following examples and comparative examples. Example 1 The sheet shown in FIG. 2A was used. Polytetrafluoroethylene powder (particle size approximately 0.25μ
m) A thickness of 50% by weight of the aqueous dispersion having a concentration of 40% by weight.
A stainless steel foil having a thickness of μm was immersed and pulled up, water was evaporated and removed by heating at 110 ° C. × 60 seconds, and further baked by heating at 390 ° C. × 90 seconds to form a fluororesin layer 22 having a thickness of 7 μm. Then, a polytetrafluoroethylene powder (with a particle diameter of about 0.
25 μm) and anatase type titanium oxide fine particles (particle diameter 0.02 μm) in a weight ratio of 6: 4, and a solid content concentration of 5
A series of treatments including immersion in a water dispersion having a concentration of 5% by weight and a silicone surfactant concentration of 1% by weight, pulling up, removing water by evaporation at 110 ° C. × 60 seconds, and baking at 390 ° C. × 90 seconds. Performed twice to form a photocatalyst layer 21 having a thickness of 18 μm,
The sheet having the structure shown in FIG. 2A was obtained by peeling off the stainless steel foil. Example 2 The sheet shown in FIG. A glass cloth having a thickness of 100 μm is immersed in the aqueous dispersion having a polytetrafluoroethylene powder concentration of 40% by weight, pulled up, water is evaporated and removed by heating at 100 ° C. for 90 seconds, and further heated at 370 ° C. for 2 minutes. Was repeated to obtain a fluororesin-impregnated glass cloth 220 having a fluororesin amount of 200 g / m ² . Next, a photocatalyst layer 21 having an adhesion amount of 230 g / m ² was formed on both surfaces of the fluororesin impregnated glass cloth in the same manner as in Example 1 to obtain a sheet having the structure shown in FIG. . Comparative Example 1 A 50 μm-thick stainless steel foil was immersed in an aqueous dispersion having a concentration of 40% by weight of polytetrafluoroethylene powder (particle diameter: about 0.25 μm) and pulled up.
Water is evaporated and removed by heating at 10 ° C. × 60 seconds, and further 390 times.
Firing by heating at 90 ° C. × 90 seconds was repeated twice, and the stainless steel foil was peeled off to obtain a single-layer fluororesin layer having a thickness of 23 μm.

In these Examples and Comparative Examples, a bacterial solution having a concentration of E. coli of 10 ⁵ cells / ml was dropped at 0.5 ml / 5 × 5 cm ² (in the example, dropped on the photocatalyst layer), and a black light ( UV intensity 0.1mW / cm
² ) Irradiation, agar culture, and colony number were measured. The number of bacteria was reduced to 10 or less in the example product by 1 hour irradiation, but the number of bacteria was hardly reduced in the comparative product. , Almost 1
0 ^five remained. Therefore, the belt was used as the sheet of the embodiment.
According to the belt conveyor according to the present invention, even if fungi propagate on the belt due to long-term operation of the conveyor, the fungi can be sterilized by active photocatalytic fine particles by irradiation with ultraviolet light after restarting, and sufficient hygiene can be achieved. Can be guaranteed.

Example 3 The sheet of Example 1 was used as an antifouling film, and the surface of the fluororesin layer of the film was coated with an argon gas as an atmospheric gas at an atmospheric pressure of 0.05 To.
Sputter etching treatment was performed at rr, discharge power of 30 W · sec / cm ² and time of 20 seconds, and a solvent-based hot melt adhesive was applied to the treated surface at a dry thickness of 15 μm. The antifouling film was pressure-bonded to the surface-bonded steel sheet using a laminator roll in the adhesive layer. Example 4 Example 4 was the same as Example 3 except that a silicone-based pressure-sensitive adhesive applied layer having a dry thickness of 40 μm was used as the adhesive layer. Comparative Example 2 A solid content concentration of 55% by weight containing polytetrafluoroethylene powder (particle diameter: about 0.25 μm) and anatase type titanium oxide fine particles (particle diameter: 0.02 μm) at a weight ratio of 6: 4, silica A 50 μm-thick stainless steel foil is immersed and pulled up in a water dispersion having a surfactant concentration of 1% by weight, and water is removed by evaporation at 110 ° C. for 60 seconds.
A series of baking at 390 ° C. × 90 seconds is performed twice,
A photocatalyst layer having a thickness of 18 μm was formed, one side of this photocatalyst layer was sputter-etched in the same manner as in Example 3, a solvent-based hot melt adhesive was applied, and a laminating was performed on the surface-bonded steel sheet in the adhesive layer. Pressure bonding was carried out using talles.

When these Examples and Comparative Examples were left outdoors for 6 months and exposed to sunlight, most of the adhesive interface was peeled off in the Comparative Examples, and floating was observed on the antifouling film. However, in Examples 3 and 4, no abnormality occurred in the bonding interface.

[0020]

In the belt conveyor according to the present invention, even if fungi grow on the belt surface due to long-term suspension, the propagated fungi can be sterilized by ultraviolet irradiation by re-driving the belt, and can be prevented by a non-contact method. Since it can be soiled, hygiene can be guaranteed while maintaining good driving characteristics of the conveyor. Also,
Even under long-term ultraviolet irradiation, the carrying state of the photocatalyst fine particles and the lamination interface of the belt can be stably maintained, and the maintenance of the driving characteristics and the assurance of hygiene can be ensured for a long time.

[Brief description of the drawings]

FIG. 1 is a drawing showing a belt conveyor according to the present invention.

FIG. 2 is a drawing showing an example of a conveyor belt according to the present invention.

FIG. 3 is a view showing another example of the conveyor belt according to the present invention.

FIG. 4 is a drawing showing another example of the conveyor belt according to the present invention.

FIG. 5 is a drawing showing another example of the conveyor belt according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Driving belt car 12 Belt car 15 Ultraviolet irradiation apparatus 2 Conveyor belt 21 Photocatalyst layer 22 Fluororesin belt main body 220 Fluororesin impregnated fiber base material A Antifouling film B Belt main body 3 Adhesive

Claims (5)

[Claims] 1. A belt conveyor comprising: a photocatalyst layer in which photocatalyst fine particles are bound with a resin binder on one or both sides of a belt; and means for irradiating one or both sides of a running belt with ultraviolet rays. 2. A conveyor belt, wherein a photocatalyst layer in which photocatalyst fine particles are bound with a fluororesin binder is provided on one or both sides of a fluororesin belt body. 3. A conveyor, wherein a photocatalyst layer comprising photocatalyst fine particles bound with a fluororesin binder is provided on one or both sides of a belt body obtained by impregnating and applying a fluororesin to a fiber core material. belt. 4. A belt having a photocatalyst layer in which photocatalyst fine particles are bound with a fluororesin binder, provided on one side of the fluororesin layer, and a fluororesin layer of an antifouling film adhered to one or both sides of the belt body. Conveyor belt. 5. A fluororesin impregnated fiber core material of an antifouling film in which a photocatalyst layer in which photocatalyst fine particles are bound with a fluororesin binder is provided on one surface of a fluororesin impregnated fiber core material, is adhered to one or both surfaces of a belt body. Conveyor belt characterized by the following: