JP2017109838A - Belt for conveyance and method for manufacturing belt for conveyance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt for conveyance excellent in durability and smoothness while having water repellency, and to provide a method for manufacturing the belt for conveyance.SOLUTION: There is provided a belt for conveyance which has a rubber layer containing thermoplastic polyurethane as a main component, an intermediate layer that is laminated on one surface of the rubber layer and contains a thermoplastic resin as a main component, and a coating layer that is laminated on a surface in an opposite side to the rubber layer of the intermediate layer and has higher water repellency than the rubber layer, where a softening point of the thermoplastic polyurethane is a melting point of the thermoplastic resin, or higher. The softening point of the thermoplastic polyurethane is preferably 135°C or higher and 160°C or lower, and a melting point of the thermoplastic resin is preferably 130°C or higher and 160°C or lower. A melt viscosity at 180°C of the thermoplastic polyurethane is preferably 100000 Pa S or less. The coating layer may contain a fluorine resin as a main component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conveyor belt and a method for manufacturing the conveyor belt.

  The transport belt is widely used for transporting raw materials such as luxury goods, intermediate products, products, and the like, and is usually formed of a laminate including a resin layer and a canvas layer. As the material of the resin layer, thermoplastic polyurethane having excellent strength and wear resistance is generally used. In this transport belt made of thermoplastic polyurethane, the surface of the transport belt made of a resin layer is contaminated or denatured when transporting sticky transported materials such as bread dough, confectionery dough, and cooked rice. There is an inconvenience such as. For this reason, it is desired to impart water repellency to the surface of the conveyor belt. In addition, thermoplastic polyurethane is desired to have a coating film that easily causes irregularities on the surface and improves the smoothness of the surface. For this reason, conventionally, a technique has been disclosed in which a thermoplastic polyurethane transport belt is immersed in a silicon solution and then heated to form a silicon film (see Japanese Patent Application Laid-Open No. 2000-351431).

  However, since the silicon coating is cured at a relatively high temperature, the thermoplastic polyurethane may be deteriorated due to a decrease in physical properties due to heat, which is undesirable in terms of durability.

JP 2000-351431 A

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a transport belt having water repellency and excellent durability and smoothness, and a method for manufacturing the transport belt. is there.

  The invention made in order to solve the above problems includes a rubber layer mainly composed of thermoplastic polyurethane, an intermediate layer laminated on one surface of the rubber layer and mainly composed of a thermoplastic resin, and the intermediate layer. A belt for transportation having a coating layer that is laminated on a surface opposite to the rubber layer and having a water repellency higher than that of the rubber layer, and the softening point of the thermoplastic polyurethane is equal to or higher than the melting point of the thermoplastic resin. is there.

  The transport belt is excellent in surface water repellency by using a coating layer having high water repellency. In addition, since the softening point of the thermoplastic polyurethane is equal to or higher than the melting point of the thermoplastic resin, the rubber layer mainly composed of the thermoplastic polyurethane and the intermediate layer mainly composed of the thermoplastic resin can be pressure-bonded at a low temperature. Therefore, deterioration due to heat can be suppressed and durability can be improved. Furthermore, since the leveling effect of the intermediate layer is improved because the softening point of the thermoplastic polyurethane is equal to or higher than the melting point of the thermoplastic resin, the coating laminated on the surface of the intermediate layer opposite to the rubber layer The adhesion of the layer and the smoothness of the conveyor belt surface can be obtained. Here, the “main component” refers to a component having the highest content, and usually refers to a component of 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more.

  The softening point of the thermoplastic polyurethane is preferably 135 ° C. or higher and 160 ° C. or lower, and the melting point of the thermoplastic resin is preferably 130 ° C. or higher and 160 ° C. or lower. Thus, when the softening point of the thermoplastic polyurethane and the melting point of the thermoplastic resin are within the above ranges, respectively, it becomes easier to press-bond the rubber layer and the intermediate layer at a low temperature and The leveling effect of the intermediate layer can be improved.

  The melt viscosity at 180 ° C. of the thermoplastic polyurethane is preferably 100,000 Pa · S or less. Thus, since the melt viscosity at 180 ° C. of the thermoplastic polyurethane is within the above range, the fluidity of the intermediate layer on the rubber layer is increased, and the leveling effect of the intermediate layer is improved. The adhesion between the rubber layer and the coating layer can be improved.

  The multi-layer is preferably composed mainly of a fluororesin. When the multilayer is mainly composed of a fluororesin, the water repellency of the conveying belt can be improved.

  Another invention made to solve the above problems is a method of manufacturing a conveyor belt using a crimping device comprising a cylindrical heating drum and an endless steel band spanned over the heating drum, Rubber layer sheet comprising thermoplastic polyurethane as a main component, intermediate layer sheet laminated on one surface of the rubber layer sheet, and thermoplastic resin as a main component, and the rubber layer of the intermediate layer sheet A laminate having a coating layer sheet laminated on the surface opposite to the sheet for rubber and having higher water repellency than the rubber layer sheet is continuously formed between the heating drum and the steel band of the crimping device. And a process of producing a belt for conveyance in which the softening point of the thermoplastic polyurethane is equal to or higher than the melting point of the thermoplastic resin.

  According to the method for manufacturing the conveyor belt, the laminate is pressurized and heated between the heating drum and the steel band of the crimping device, and thus the adhesion and smoothness between the rubber layer and the coating layer. Can be improved. Moreover, since the said laminated body is continuously sent between the said heating drum and the said steel band, a laminated body is heated efficiently and the deterioration by the heat | fever of the said rubber layer can be suppressed. Thereby, the said belt for conveyance can be manufactured reliably.

  Here, the “conveying belt” is a concept including not only an endless shape but also an endless shape. The “outer surface” means a conveying surface, and in the case of an endless conveying belt, it means an outer surface.

  The conveyor belt of the present invention is excellent in durability, adhesion and smoothness while having water repellency. According to the method for manufacturing a conveyor belt of the present invention, it is possible to reliably manufacture a conveyor belt that has water repellency and is excellent in durability and improves the adhesion and smoothness between the rubber layer and the coating layer. .

It is a typical sectional view of the belt for conveyance concerning a 1st embodiment of the present invention. It is a schematic diagram for demonstrating the manufacturing method of the belt for conveyance which concerns on 1st Embodiment of this invention. It is a typical sectional view of the belt for conveyance concerning a 2nd embodiment of the present invention.

  Hereinafter, embodiments of a conveyor belt and a conveyor belt manufacturing method according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
[Conveyor belt]
FIG. 1 is a schematic cross-sectional view of a conveyor belt 1 according to the first embodiment of the present invention. The conveyor belt 1 includes a canvas 5, a rubber layer 4 laminated on one surface of the canvas 5, an intermediate layer 3 laminated on a surface of the rubber layer 4 opposite to the canvas 5, and an intermediate layer 3. And a coating layer 2 laminated on the surface opposite to the rubber layer 4. The rubber layer 4 and the canvas 5 serve as the base of the transport belt 1, and the intermediate layer 3 and the coating layer 2 laminated on the outer surface of the intermediate layer 3 serve as the film layer of the transport belt 1. Since the intermediate layer 3 is laminated on the outer surface of the rubber layer 4, the film layer is laminated on the outer surface of the rubber layer 4, and the covering layer 2 becomes the outermost layer.

  The rubber layer 4 is mainly composed of thermoplastic polyurethane. The intermediate layer 3 is mainly composed of a thermoplastic resin. The coating layer 2 has a larger contact angle with water and higher water repellency than the rubber layer 4.

  The conveying belt 1 rotates while interlocking with a pulley by a driving mechanism (not shown) so that the coating layer 2 is on the outside. Accordingly, the outer surface of the coating layer 2 becomes the transport surface.

(Canvas)
The canvas 5 holds the tension applied to the conveyor belt 1 and imparts mechanical strength.

  The canvas 5 is made of woven fabric or knitted fabric. Examples of the yarn constituting the canvas 5 include polyester yarn, nylon yarn, cotton yarn, rayon yarn and the like. The yarn constituting the canvas 5 is preferably a polyester yarn because it is excellent in strength and flexibility and does not generate toxic gases such as nitrogen oxides during combustion. The canvas 5 is not particularly limited with respect to the woven structure, the thickness of the yarn, and the type of the yarn.

  In order to improve the adhesion to the rubber layer 4, the canvas 5 may be subjected to a primer treatment impregnated with, for example, a urethane resin adhesive solution.

  The lower limit of the average thickness of the canvas 5 is preferably 0.1 mm, and more preferably 0.3 mm. The upper limit of the average thickness is preferably 1.5 mm, and more preferably 1.0 mm.

(Rubber layer)
The rubber layer 4 is mainly composed of thermoplastic polyurethane. In addition to the thermoplastic polyurethane, the rubber layer 4 may contain other resins as necessary, and may contain a known additive added to the thermoplastic polyurethane for belts.

  A well-known thing can be used as a thermoplastic polyurethane. Although the manufacturing method of thermoplastic polyurethane is not specifically limited, Typically, the method of making about equimolar polyisocyanate compound and polyol compound, and a chain extender react, for example at 60 degreeC or more and 220 degrees C or less is mentioned. In this case, you may add a catalyst etc. as needed. The thermoplastic polyurethane is generally a resin having a linear carbon chain structure, but preferably has a partially crosslinked structure in a linear structural molecule. By having a partially crosslinked structure in the linear structural molecule, the mechanical strength is improved as compared with the linear carbon chain structure.

Examples of the polyisocyanate compound include phenylene diisocyanate, 1,5-naphthalene diisocyanate (NDI), tolylene diisocyanate (TDI), 4,4′-diphenyl diisocyanate, diphenylmethane diisocyanate (MDI), 4,4′-tolidine diisocyanate (TODI). ), 4,4′-diphenyl ether diisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI) and the like aromatic diisocyanates;
Cyclopentane diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, bis (isocyanatomethyl) cyclohexane, etc. Group diisocyanates;
Examples thereof include aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, and trimethylhexamethylene diisocyanate. These polyisocyanate compounds can be used alone or in combination of two or more.

  Examples of the polyol compound include polyester polyols, polycarbonate polyols, polyether polyols, and polyolefin polyols. These polyol components can be used alone or in combination of two or more.

Examples of the polyester polyol include aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid or dialkyl esters thereof;
At least one dicarboxylic acid selected from aliphatic dicarboxylic acids such as adipic acid, glutaric acid and succinic acid or dialkyl esters thereof or the like, and ethylene glycol, propylene glycol, trimethylene glycol, 1, 3 -C _2-10 alkanediols such as butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol;
Examples include a reaction product with at least one alkanediol component selected from di- or tri-C _2-10 alkanediol such as diethylene glycol.

Specific examples of polyester polyols based on adipic acid as a dicarboxylic acid component include polyethylene adipate (PEA), polydiethylene adipate (PDA), polypropylene adipate (PPA), polytetramethylene adipate (PBA), Examples thereof include polyhexamethylene adipate (PHMA) and a copolymer obtained by combining these components. Polyester polyols include homopolymers or copolymers of lactones (C _3-14 lactones such as ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone).

  Examples of the polycarbonate-based polyol include a reaction product of a polyol such as an alkane polyol, a polyether-based polyol, and a polyester-based polyol with a short-chain dialkyl carbonate such as dimethyl carbonate. A representative example of the polycarbonate polyol is polyhexamethylene carbonate (PHC).

Examples of polyether polyols include homopolymers or copolymers of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, and 3-methyltetrahydrofuran;
A homo- or copolymer comprising tetramethylene ether glycol;
An alkylene oxide adduct of bisphenol A or hydrogenated bisphenol A such as an adduct obtained by adding 1 to 5 moles of C _2-4 alkylene oxide to a hydroxy group can be used.

  Examples of the polyolefin-based polyol include polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, castor oil-modified polyol, and those obtained by introducing a hydroxyl group at the terminal of a copolymer of butadiene and styrene or acrylonitrile.

  Among these polyol compounds, polycarbonate-based polyols are more preferable from the viewpoint of improving heat resistance.

  As a minimum of a number average molecular weight of a polyol compound, 400 is preferred, 500 is more preferred, and 550 is still more preferred. The upper limit of the number average molecular weight is preferably 10,000, more preferably 8,000, and still more preferably 5,000. The polyol compound may be crystalline or non-crystalline. Here, “number average molecular weight” refers to a value measured using gel permeation chromatography (GPC) in accordance with JIS-K-7252-1 (2008).

Examples of the chain extender include aliphatic diols having 2 to 14 carbon atoms such as ethanediol, 1,6-hexanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol and the like;
Diesters of terephthalic acid such as bisethylene glycol terephthalate and bis-1,4-butanediol terephthalate with glycols having 2 to 4 carbon atoms;
Hydroxyalkylene ethers of hydroquinone such as 1,4-di (β-hydroxyethyl) hydroquinone);
Ethoxylated bisphenols such as 1,4-di (β-hydroxyethyl) bisphenol A;
Aliphatic diamines such as isophoronediamine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, N-methylpropylene-1,3-diamine, N, N′-dimethyl-ethylenediamine;
2,4-tolylenediamine, 2,6-tolylenediamine, 3,5-diethyl-2,4-tolylenediamine, 3,5-diethyl-2,6-tolylenediamine, primary mono-, di- And aromatic diamines such as-, tri- or tetraalkyl-substituted-4,4'-diaminodiphenylmethane.

  Examples of the other resin include polyolefin, polycycloolefin, polydiene, polystyrene, styrene copolymer, acrylic resin, polyester, polyamide, thermosetting polyurethane, and polyvinyl chloride.

  As a minimum of a softening point of thermoplastic polyurethane which is the main ingredients of rubber layer 4, 135 ° C is preferred, 138 ° C is more preferred, and 140 ° C is still more preferred. The upper limit of the softening point of the thermoplastic polyurethane is preferably 160 ° C, more preferably 155 ° C, and further preferably 150 ° C. When the softening point of the thermoplastic polyurethane is less than the lower limit, the rubber layer 4 becomes too soft when the rubber layer 4 and the intermediate layer 3 are subjected to thermocompression bonding, so that sufficient moldability may not be obtained. Moreover, when the softening point of the said thermoplastic polyurethane exceeds the said upper limit, it may become difficult to perform the thermocompression bonding with the rubber layer 4 and the intermediate | middle layer 3 at low temperature. Here, the “softening point” means a softening point measured by a temperature raising method based on JIS-K-7311 (1999).

  The softening point of the thermoplastic polyurethane is not less than the melting point of the thermoplastic resin. When the softening point of the thermoplastic polyurethane is equal to or higher than the melting point of the thermoplastic resin, the rubber layer 4 and the intermediate layer 3 can be pressure-bonded at a low temperature, and deterioration due to heat can be suppressed. When the softening point of the thermoplastic polyurethane is less than the melting point of the thermoplastic resin, the effect of thermocompression bonding between the rubber layer 4 and the intermediate layer 3 becomes insufficient, so that the rubber layer 4 and the intermediate layer 3 are in close contact with each other. It is difficult to obtain a high effect on the property and leveling.

  Further, the softening point of the thermoplastic polyurethane is preferably higher than the melting point of the thermoplastic resin, and the lower limit of the difference between the softening point of the thermoplastic polyurethane and the melting point of the thermoplastic resin is 0.1 ° C. Preferably, 3 ° C. is more preferable. The upper limit of the difference between the softening point of the thermoplastic polyurethane and the melting point of the thermoplastic resin is preferably 25 ° C, more preferably 20 ° C. When the difference between the softening point and the melting point is less than the lower limit, the fluidity of the thermoplastic resin at the time of thermocompression bonding between the rubber layer 4 and the intermediate layer 3 is lowered, and a high effect on leveling is obtained. There is a risk of not being able to. In addition, when the difference between the softening point and the melting point exceeds the upper limit, the effect of thermocompression bonding between the rubber layer 4 and the intermediate layer 3 cannot be sufficiently obtained, so that the adhesion between the rubber layer 4 and the intermediate layer 3 is achieved. There is a possibility that a high effect on the property and leveling cannot be obtained.

  The lower limit of the melt viscosity at 180 ° C. of the thermoplastic polyurethane as the main component of the rubber layer 4 is preferably 5,000 Pa · S, and more preferably 7,000 Pa · S. The upper limit of the melt viscosity at 180 ° C. of the thermoplastic polyurethane is preferably 40,000 Pa · S or less, and more preferably 30,000 Pa · S. When the melt viscosity is less than the lower limit, the rubber layer 4 becomes too soft during the thermocompression bonding of the rubber layer 4 and the intermediate layer 3, and thus sufficient moldability may not be obtained. When the melt viscosity exceeds the upper limit, the thermocompression bonding between the rubber layer 4 and the intermediate layer 3 becomes insufficient, so that a high effect on the adhesion and leveling between the rubber layer 4 and the intermediate layer 3 cannot be obtained. There is a fear. Here, “melt viscosity” means a melt viscosity measured by a temperature raising method based on JIS-K-7311 (1999).

  As a minimum of average thickness of rubber layer 4, 0.1 mm is preferred, 0.2 mm is more preferred, and 0.3 mm is still more preferred. The upper limit of the average thickness of the rubber layer 4 is preferably 3 mm, more preferably 2 mm, and even more preferably 1 mm. When the average thickness of the rubber layer 4 is less than the above lower limit, the excellent strength of the conveyor belt 1 may not be obtained. When the average thickness of the rubber layer 4 exceeds the above upper limit, it may be difficult to use the rubber layer 4 for a conveying device having a small pulley diameter.

(Middle layer)
The intermediate layer 3 is mainly composed of a thermoplastic resin. Examples of the thermoplastic resin constituting the intermediate layer 3 include polyamide (PA), polyphenylene sulfide (PPS), polyether sulfone (PES), liquid crystal polymer (LCP), polyether ether ketone (PEEK), thermoplastic polyamide ( TPI), polyetherimide (PEI), polyamideimide (PAI) and the like. Of these, polyamide (PA) such as nylon is preferable in consideration of moldability.

  The lower limit of the melting point of the thermoplastic resin that is the main component of the mid layer 3 is preferably 130 ° C, more preferably 140 ° C. The upper limit of the melting point of the thermoplastic resin is preferably 170 ° C, more preferably 160 ° C. If the melting point is less than the lower limit, the thermoplastic resin becomes too soft during the thermocompression bonding of the rubber layer 4 and the intermediate layer 3, and the moldability of the intermediate layer 3 may be reduced. If the melting point exceeds the upper limit, it may be difficult to press-bond the rubber layer 4 and the intermediate layer 3 at a low temperature. Here, the “melting point” means a melting point measured based on ISO 11357-3 of a thermoplastic resin.

  The lower limit of the average thickness of the intermediate layer 3 is preferably 25 μm, more preferably 50 μm, and even more preferably 75 μm. The upper limit of the average thickness of the intermediate layer 3 is preferably 3 mm, more preferably 2 mm, and even more preferably 1 mm. When the average thickness of the intermediate layer 3 is less than the above lower limit, a high leveling effect between the rubber layer 4 and the intermediate layer 3 may not be obtained. When the average thickness of the intermediate layer 3 exceeds the upper limit, high adhesion between the rubber layer 4 and the intermediate layer 3 may not be obtained.

(Coating layer)
The covering layer 2 has higher water repellency than the rubber layer 4 and has a function of protecting the surface of the conveying belt 1. The resin used for the coating layer 2 is not particularly limited as long as the resin has water repellency. From the viewpoint of strength and water repellency, the main component of the coating layer 2 is preferably a fluororesin. Here, high water repellency means that the contact angle with water is large. “Contact angle” refers to a value measured according to JIS-R-3257 (1999).

  As a minimum of a contact angle of coating layer 2, 80 degrees is preferred and 85 degrees is more preferred. As an upper limit of the coating layer 2, 140 degrees is preferable and 120 degrees is more preferable. When the contact angle of the coating layer 2 is less than the lower limit, sufficient water repellency may not be obtained. Moreover, when the contact angle of the coating layer 2 exceeds the said upper limit, there exists a possibility that a conveyed product cannot be conveyed in the stable state.

Examples of the fluororesin include homopolymers of fluorine-containing monomers such as polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyvinyl fluoride, polytrifluorochloroethylene, and the like;
Copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, copolymer of tetrafluoroethylene and vinylidene fluoride, copolymer of tetrafluoroethylene and hexafluoropropylene, copolymer of ethylene and tetrafluoroethylene , A copolymer of tetrafluoroethylene and vinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, a copolymer of vinyl fluoride and vinylidene fluoride, a fluorinated vinylidene and an acrylic monomer Examples thereof include copolymers, copolymers of vinylidene fluoride and trifluorochloroethylene, copolymers of fluoroterpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers. Among these, from the viewpoint of making the friction coefficient of the surface of the conveyor belt 1 smaller, the ease of coextrusion with the intermediate layer 3, and the viewpoint of improving the peel strength of the conveyor belt 1, A copolymer of vinylidene fluoride and hexafluoropropylene is more preferable.

  The coating layer 2 may contain a resin other than the fluororesin as necessary, or may contain a known additive added to the coating layer of the conveyor belt.

  As a minimum of melting | fusing point of the coating layer 2, 160 degreeC is preferable and 170 degreeC is more preferable. As an upper limit of melting | fusing point of the coating layer 2, 200 degreeC is preferable and 190 degreeC is more preferable. If the melting point of the coating layer 2 is less than the above lower limit, the coating layer 2 becomes too soft during thermocompression bonding, and the moldability of the coating layer 2 may be reduced. When the melting point of the coating layer 2 exceeds the above upper limit, it may be difficult to pressure-bond the rubber layer 4 and the intermediate layer 3 at a low temperature.

  As a minimum of average thickness of coating layer 2, 10 micrometers is preferred, 15 micrometers is more preferred, and 25 micrometers is still more preferred. The upper limit of the average thickness of the coating layer 2 is preferably 500 μm, more preferably 400 μm, and even more preferably 350 μm. When the average thickness of the coating layer 2 is less than the above lower limit, thickness unevenness occurs in the coating layer 2 during thermocompression bonding, and the water repellency may partially deteriorate. When the average thickness of the coating layer 2 exceeds the above upper limit, there is a possibility that inconveniences such as wrinkles and warping may occur in the conveying belt 1 due to shrinkage of the coating layer 2 or the like.

  Since the conveyance belt 1 has the above characteristics, it can be suitably used as a transmission belt in addition to the conveyance belt. Moreover, the said conveyor belt 1 can be used suitably also for conveyance of food etc. with much moisture and adhesiveness.

[Conveying belt manufacturing method]
Hereinafter, as an embodiment of the method for manufacturing the conveying belt 1 according to the first embodiment, a method for manufacturing an end-shaped conveying belt will be described. Although it does not specifically limit as a manufacturing method of the said conveyor belt 1, The manufacturing method of the conveyor belt 1 in this embodiment is as follows.
(1) Substrate laminating step (2) Film layer laminating step (3) Crimping step (4) Cooling step (5) A joining step for joining the ends of the conveyor belt is provided. Hereinafter, each step will be described.

(Substrate lamination process)
In the substrate lamination step, a laminate for forming a substrate is formed. The laminate for forming a substrate has a canvas sheet 15 and a rubber layer sheet 14 mainly composed of thermoplastic polyurethane. Moreover, the softening point of the thermoplastic polyurethane used for the rubber layer resin composition is equal to or higher than the melting point of the thermoplastic resin used for the intermediate layer resin composition. In this step, the canvas sheet 15 and the rubber layer sheet 14 are laminated by extrusion. As the extrusion molding method, an extrusion lamination method is preferable from the viewpoints of quality stability and cost. Specifically, a rubber layer resin composition containing thermoplastic polyurethane as a main component is laminated with a primer-treated canvas while being extruded with a T-die to form a laminate. In extrusion molding, the heating temperature is, for example, in the range of 160 ° C. or higher and 200 ° C. or lower.

(Film layer lamination process)
In the film layer laminating step, a laminate for forming a film layer is formed. The laminate for forming a film layer includes an intermediate layer sheet 13 mainly composed of a thermoplastic resin, and a coating layer sheet 12 having a higher water repellency than the rubber layer sheet 14. The laminate having the intermediate layer sheet 13 and the coating layer sheet 12 is formed by coextrusion. By coextrusion, the intermediate layer resin composition and the coating layer resin composition are continuously melt-pressed to form a laminate for forming a film layer. By forming the laminate for forming the film layer by coextrusion, the adhesion between the intermediate layer sheet 13 and the coating layer sheet 12 of the laminate can be improved. The peel strength of the belt can be improved.

  As a heating condition in the co-extrusion in the film layer lamination step, for example, it can be set to 200 ° C. or more and 300 ° C. or less.

(Crimping process)
In the pressure-bonding step, a laminate for forming a base body having a rubber layer sheet 14 and a canvas sheet 15, a covering layer sheet 12, and an intermediate layer sheet 13 are used by using a continuous compression molding machine called a rotocure. The laminate for forming a film layer is thermocompression bonded. FIG. 2 is a schematic diagram for explaining a crimping step in the method for manufacturing the conveyance belt 1.

  As shown in FIG. 2, in the crimping step, a rotocure 50 that is a crimping device including a cylindrical heating drum 40 and an endless steel band 45 spanned over the heating drum 40 is used.

  Specifically, the rot cure 50 includes a steel band 45, a heating drum 40, and three rolls 42a, 42b, and 42c. In the crimping step, first, a film layer having a laminate for forming a base body having a canvas sheet 15 and a rubber layer sheet 14, a covering layer sheet 12, and an intermediate layer sheet 13 from two hanging platforms (not shown). The forming laminate is fed out. Next, the intermediate layer sheet 13 of the laminate for forming a film layer is laminated on one surface of the rubber layer sheet 14 of the laminate for forming a substrate. Thus, the canvas sheet 15, the rubber layer sheet 14 laminated on one surface of the canvas sheet 15, the intermediate layer sheet 13 laminated on one surface of the rubber layer sheet 14, A laminated body is formed in which the covering layer sheet 12 is laminated on the surface opposite to the rubber layer sheet 14 of the intermediate layer sheet 13.

  Next, the laminated body is continuously sent between the heating drum 40 and the steel band 45 of the rot cure 50 to pressurize and heat. The laminate and the steel band 45 are transported so that the surface of the laminate opposite to the steel band 45 comes into contact with the peripheral surface of the heating drum 40, and the intermediate layer sheet 13 of the laminate for film layer formation; The rubber layer sheet 14 of the laminate for forming the substrate is thermocompression bonded. Heat is applied by the heating drum 40 and the back heater 46, and pressure is applied by the steel band 45. In this way, the laminate for forming the film layer is laminated on the surface of the rubber layer sheet 14 of the laminate for forming the substrate. And the laminated body 10 after thermocompression bonding leaves the rot cure 50, and is wound up by the winding device which is not shown in figure.

  The lower limit of the temperature in thermocompression bonding between the intermediate layer sheet 13 and the rubber layer sheet 14 is preferably 130 ° C, more preferably 140 ° C. As an upper limit of the said temperature, 170 degreeC is preferable and 160 degreeC is more preferable. When the temperature in the thermocompression bonding between the intermediate layer sheet 13 and the rubber layer sheet 14 is less than the lower limit, the rubber layer sheet 14 becomes too soft at the time of thermocompression bonding, so that desirable dimensional stability and smoothness of the conveying belt 1 can be obtained. May be difficult to maintain. When the said temperature exceeds the said upper limit, there exists a possibility that it may become difficult to suppress degradation by the heat | fever of thermocompression bonding.

As a pressurizing condition in the rot cure 50, for example, 10 kg / cm ² or more and 100 kg / cm ² can be set.

(Cooling process)
In this step, the laminate 10 that has been pressure-bonded in the pressure-bonding step is cooled.

  Examples of the cooling method include air cooling and water cooling. Although there are no particular limitations on the cooling temperature and time conditions, examples of the setting conditions include conditions under which the internal temperature of the formed laminate can be cooled to 10 ° C. or higher and 40 ° C. or lower.

(Joining process)
In this step, after the cooled laminated body 10 is cut to a predetermined length, the end portions of the laminated body 10 are joined by joint processing to form the conveying belt 1. For example, a urethane-based adhesive can be used as the adhesive at the joining portion. As the joint processing, for example, a lap joint method, a finger joint method, a double finger joint method, or the like can be used.

  According to the method for manufacturing the conveyor belt, the laminated body in which the canvas sheet 15, the rubber layer sheet 14, the intermediate layer sheet 13, and the covering layer sheet 12 are laminated together with the heating drum 40 of the rot cure 50 and the steel band. Since the laminated body is pressurized in a state where the steel band 45 is in close contact with the steel band 45 by being continuously sent to and pressed between the rubber layer 4 and the rubber layer 4 and the coating layer 2 of the conveyor belt 1. Adhesiveness and smoothness can be improved. Further, in the joint portion where both ends of the conveyance belt 1 are endlessly (joint) by heat fusion, a step due to the joint of the coating layer is less likely to occur, and the smoothness of the surface of the conveyance belt is further improved. Can do. Further, since the laminated body and the steel band 45 are conveyed so that the surface opposite to the steel band 45 is in contact with the peripheral surface of the heating drum 40, the laminated body is efficiently heated and the rubber layer sheet 14 is heated. Deterioration due to heat can be suppressed. Thereby, the said belt for conveyance can be manufactured reliably.

Second Embodiment
[Conveyor belt]
In the conveyor belt according to the second embodiment of the present invention, two layers of canvas are laminated as a base via a resin layer.

  FIG. 3 is a schematic cross-sectional view of the conveying belt 20 according to the third embodiment of the present invention. The transport belt 20 includes a resin layer 6, a pair of first canvas 5a and second canvas 5b stacked via the resin layer 6, and a rubber layer 4 stacked on one surface of the first canvas 5a. The intermediate layer 3 laminated on the surface of the rubber layer 4 opposite to the first canvas 5a, and the coating layer 2 laminated on the surface of the intermediate layer 3 opposite to the rubber layer 4 are provided. The rubber layer 4, the pair of first canvas 5 a and second canvas 5 b, and the resin layer 6 serve as a base of the transport belt 20. Further, the intermediate layer 3 and the coating layer 2 serve as a film layer of the transport belt 20. Since the rubber layer 4, the intermediate layer 3, and the covering layer 2 are the same as those in the first embodiment, the same numbers are assigned and the description is omitted.

(1st canvas and 2nd canvas)
The first canvas 5a and the second canvas 5b are not particularly limited with respect to the woven structure, the thickness of the thread, and the type of the thread, and the same thing as the canvas 5 of the first embodiment can be used. Further, the first canvas 5a and the second canvas 5b may be made of the same type of yarn, or may be made of different types of yarn.

  In order to improve the adhesion between the rubber layer 4 and the resin layer 6, the first canvas 5a and the second canvas 5b may be subjected to primer treatment.

  The average thickness of the first canvas 5a and the second canvas 5b may be the same or different. About the average thickness of the 1st canvas 5a and the 2nd canvas 5b, 0.1 mm is preferable as a minimum of average thickness like 1st Embodiment, and 0.3 mm is more preferable. The upper limit of the average thickness is preferably 1.5 mm, and more preferably 1.0 mm.

(Resin layer)

  Examples of the resin constituting the resin layer 6 include thermoplastic polyurethane, polyolefin, polycycloolefin, polydiene, polystyrene, styrene copolymer, acrylic resin, polyester, polyamide, thermosetting polyurethane, and polyvinyl chloride.

  As a minimum of average thickness of resin layer 6, 0.1 mm is preferred and 0.3 mm is still more preferred. The upper limit of the average thickness of the resin layer 6 is preferably 1.0 mm, and more preferably 0.8 mm. When the average thickness of the resin layer 6 is less than the lower limit, sufficient adhesion to the first canvas 5a and the second canvas 5b may not be obtained. When the average thickness of the resin layer 6 exceeds the above upper limit, there is a possibility that a sufficient pressure contact effect in the extrusion lamination of the substrate cannot be obtained.

  Since the conveyance belt 20 has the above characteristics, in addition to the effect of the conveyance belt 1 according to the first embodiment of the present invention, the conveyance belt 20 is improved in mechanical strength and conveyed. The thickness of the service belt 20 can be easily adjusted.

[Conveying belt manufacturing method]
The manufacturing method of the conveyor belt 20 is not particularly limited, but the manufacturing method of the conveyor belt in the present embodiment is as follows.
(1) Substrate laminating step (2) Film layer laminating step (3) Crimping step between substrate and film layer (4) Cooling step (5) A joining step for joining the end portions of the transport belt is provided. The (2) film layer lamination step, (3) the pressure bonding step between the substrate and the film layer, (4) the cooling step, and (5) the joining step for joining the end portions of the transport belt are the same as in the first embodiment. Therefore, the description will be omitted, and only (1) the substrate lamination step will be described.

(Substrate lamination process)
In the substrate lamination step, a substrate-forming laminate having a pair of first canvas sheet and second canvas sheet, resin layer sheet and rubber layer sheet is formed. In this step, a pair of first canvas sheet and second canvas sheet laminated via the resin layer sheet and the rubber layer sheet are laminated by extrusion molding. The pair of first canvas sheets and second canvas sheets are preliminarily subjected to primer treatment. As the extrusion molding method, as in the first embodiment, the extrusion lamination method is preferable from the viewpoints of quality stability and cost. In the extrusion lamination method, the resin layer composition is melt-extruded into a first canvas in a thin film form, and the rubber layer resin composition is melt-extruded in a thin film form into a second canvas to integrate them. A laminate including the first canvas sheet, the second canvas sheet, the resin layer sheet, and the rubber layer sheet is formed. In extrusion molding, the heating temperature is, for example, in the range of 160 ° C. or higher and 200 ° C. or lower as in the first embodiment.

  According to the method for manufacturing the conveyor belt 20, in addition to the effect of the method for manufacturing the conveyor belt 1 according to the first embodiment of the present invention, the conveyor is improved in mechanical strength and easily adjusted in thickness. Can be reliably manufactured.

[Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the above-described embodiment, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. The

  For example, in the conveyor belt, the base body may not be provided with a canvas, and may be composed only of a rubber layer. Since the base of the conveyor belt is composed only of the rubber layer, the conveyor belt can be easily manufactured.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Examples 1-4 and Comparative Examples 1-2]
About Examples 1-4 and Comparative Examples 1 and 2, the belt for conveyance was produced using the water-repellent resin shown in Table 1, the thermoplastic resin, and the thermoplastic polyurethane as a material. In Examples 1 to 4 and Comparative Examples 1 to 2, a conveyor belt was produced based on the method for manufacturing a conveyor belt according to the second embodiment described above. First, using an extruder, heat-melt fluororesin, which is a water-repellent resin for forming a coating layer, and polyamide, which is a thermoplastic resin for forming an intermediate layer, and extrusion molding at a molding temperature of 240 ° C. did. The laminated body which has the sheet | seat for coating layers and the sheet | seat for intermediate | middle layers was obtained by cooling after that. Next, a thermoplastic polyurethane, which is a resin layer composition, is melt-extruded in a thin film shape onto the first polyester canvas by an extrusion lamination method, and a thermoplastic polyurethane, which is a resin composition for the rubber layer, is formed into a thin film form on the second polyester canvas. These were integrated with each other by being melt-extruded to form a laminate for forming a substrate. The heating temperature in extrusion lamination was 180 ° C. Next, the rubber layer and the laminate were cooled after thermocompression bonding at 155 ° C. using a roto-cure. And the edge parts of a laminated body are joined by joint processing, the average thickness of a coating layer is 50 micrometers, the average thickness of an intermediate layer is 100 micrometers, the average thickness of a rubber layer is 350 micrometers, and the average thickness of the first and second polyester canvases A conveyor belt having a thickness of 0.5 mm and an average thickness of the resin layer of 350 μm was prepared.

(Coating layer)
ETFE (tetrafluoroethylene copolymer, Asahi Glass Co., Ltd., Fluon LH-8000) was used as the water-repellent resin for the coating layer.

(Middle layer)
As the intermediate layer thermoplastic resin, polyamide PA12 (nylon 12, Ube Industries, Ltd. 9040X1, 9048X1, and 9063X1) was used.

(Rubber layer)
As the thermoplastic polyurethane of the rubber layer, E985PTFO, E980PTFI and E385PTFK manufactured by Nippon Milactolan Co., Ltd. were used.

<Evaluation>
For Examples 1 to 4 and Comparative Examples 1 and 2 obtained as described above, durability, thickness variation in the width direction and length direction of the belt, dimensional stability after thermocompression bonding, and planar smoothness Evaluated.

(Softening point of thermoplastic polyurethane)
The softening point of the thermoplastic polyurethane was measured by a temperature raising method based on JIS-K-7311 (1999).

(Polyamide melting point)
The melting point of the polyamide was measured based on ISO11357-3 using a differential scanning calorimeter (DSC).

(Viscosity of thermoplastic polyurethane at 180 ° C)
The viscosity of the thermoplastic polyurethane at 180 ° C. was measured by a temperature raising method based on JIS-K-7311 (1999).

(durability)
In accordance with JIS-K-6854-2 (1999), a peel adhesion strength test was performed at 180 ° C., and the durability was evaluated by observing the peeled state between the intermediate layer and the rubber layer. The case where peeling was not seen was set to A, the case where peeling area was 5% or less was set to B, and the case where peeling area exceeded 5% was set to C.

(Adhesion)
The adhesion was evaluated by measuring the thickness variation in the width direction and the length direction of the conveyor belt. The thickness variation in the width direction and length direction of the conveyor belt is measured by measuring the thickness of the conveyor belt after thermocompression bonding at predetermined six locations, and the difference between the maximum and minimum measured values is within 50 μm. The case was A, the difference was more than 50 μm, and the difference was 100 μm or less, B, and the difference was more than 100 μm, C.

(Dimensional stability after thermocompression bonding)
For dimensional stability after thermocompression bonding, the length in the longitudinal direction of the conveying belt after thermocompression bonding is measured, and the rate of change of the measured value relative to the length in the longitudinal direction of the conveying belt before thermocompression bonding is within 1%. In the case of A, the case where the rate of change was within 2% was designated as B, and the case where the rate of change exceeded 2% was designated as C.

(Surface smoothness)
The presence or absence of unevenness on the belt surface was visually judged.

  As shown in Table 1, Examples 1 to 4 in which the softening point of the thermoplastic polyurethane is equal to or higher than the melting point of the thermoplastic resin is excellent in peel adhesion strength, and there is variation in thickness in the width direction and the length direction. Small and good results in durability and adhesion were obtained. In addition, good results were obtained in dimensional stability and flatness after thermocompression bonding. In particular, Example 1 in which the viscosity of the thermoplastic polyurethane at 180 ° C. is 9135 Pa · s was excellent in all of durability, adhesion, dimensional stability after thermocompression bonding, and flatness of the flat surface. In Examples 3 and 4, the thermoplastic polyurethane has a high viscosity at 180 ° C. of 27221 Pa · s. In Examples 3 and 4, the durability and dimensional stability after thermocompression bonding are B, and the viscosity is 7450 Pa · s. In Example 2, since the adhesiveness is B, it can be seen that a more excellent effect can be obtained when the viscosity of the thermoplastic polyurethane at 180 ° C. is around 9000 Pa · s.

  On the other hand, when compared with Examples 1 to 4, Comparative Examples 1 and 2 in which the softening point of the thermoplastic polyurethane is less than the melting point of the thermoplastic resin are adhesiveness, dimensional stability after thermocompression bonding, and surface smoothness. Was inferior. In other words, the conveyance belt according to the embodiment of the present invention has water repellency while being excellent in durability and smoothness and excellent in adhesion and dimensional stability and has sufficient characteristics as a conveyance belt. did.

  According to the method for manufacturing a transport belt of the present invention, it is possible to reliably manufacture a transport belt that has water repellency and is excellent in durability, and improves the adhesion between the rubber layer and the coating layer and the smoothness of the surface. Can do. Therefore, the said conveyance belt can be used suitably as a power transmission conveyance belt other than a conveyance belt.

DESCRIPTION OF SYMBOLS 1,20 Conveying belt 2 Covering layer 3 Intermediate | middle layer 4 Rubber layer 5 Canvas 5a 1st canvas 5b 2nd canvas 6 Resin layer 10 Laminated body 12 Sheet | seat for coating layers 13 Sheet | seat for intermediate | middle layers 14 Sheet | seat for rubber layers 15 Sheet | seat for canvases 40 Heating drum 42a, 42b, 42c Roll 45 Steel band 46 Back heater 50 Roto cure

Claims (5)

A rubber layer mainly composed of thermoplastic polyurethane;
An intermediate layer that is laminated on one surface of the rubber layer and has a thermoplastic resin as a main component,
The intermediate layer is laminated on the surface opposite to the rubber layer, and includes a coating layer having higher water repellency than the rubber layer,
A conveying belt in which a softening point of the thermoplastic polyurethane is equal to or higher than a melting point of the thermoplastic resin.   The conveyor belt according to claim 1, wherein the thermoplastic polyurethane has a softening point of 135 ° C. or higher and 160 ° C. or lower, and the thermoplastic resin has a melting point of 130 ° C. or higher and 160 ° C. or lower.   The conveying belt according to claim 1 or 2, wherein the thermoplastic polyurethane has a melt viscosity at 180 ° C of 100,000 Pa · S or less.   The conveyor belt according to claim 1, wherein the multilayer is mainly composed of a fluororesin. A manufacturing method of a conveyor belt using a crimping device comprising a cylindrical heating drum and an endless steel band spanned over the heating drum,
Rubber layer sheet comprising thermoplastic polyurethane as a main component, intermediate layer sheet laminated on one surface of the rubber layer sheet, and thermoplastic resin as a main component, and the rubber layer of the intermediate layer sheet A laminate having a coating layer sheet laminated on the surface opposite to the sheet for rubber and having higher water repellency than the rubber layer sheet is continuously formed between the heating drum and the steel band of the crimping device. Comprising the steps of sending and pressurizing and heating,
A method for producing a conveyor belt, wherein the thermoplastic polyurethane has a softening point equal to or higher than a melting point of the thermoplastic resin.

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