JP2022166381A - Toothed belt for transportation - Google Patents

Abstract

To provide a toothed belt for transportation with high flexibility, small belt bending resistance, and excellent swelling resistance.SOLUTION: A toothed belt for transportation has a belt body, and a tension body embedded in the belt body, where the belt body is made of a rubber composition mainly composed of a rubber component containing NBR and EPDM at a mass ratio of 75/25 to 50/50, and belt bending rigidity per 6 mm belt width is 0.080 N cm2 or less.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to toothed belts for conveying paper sheets, and more particularly to toothed belts for conveying paper sheets.

2. Description of the Related Art Electrophotographic apparatuses, automatic vending machines, change machines, ticket vending machines, and the like use toothed belts for carrying paper sheets such as paper, bills, and credit cards. Such toothed conveyor belts are required to have high flexibility and low belt bending resistance in order to reduce the size of the power source for space saving, and of course, to have good conveying power. be done. As a conveyor belt that meets such requirements, the applicant has proposed a transmission belt that has high flexibility and low belt bending resistance (Patent Document 1).

Toothed belts for transporting paper sheets handle high-value items such as banknotes and tickets. Stability is required. Here, for example, banknotes and credit cards have sebum, oil derived from food, etc. attached to their surfaces, and since tickets are transported immediately after being printed, the ink may not be sufficiently dried. Therefore, the toothed belt for conveyance is required to have swelling resistance so that it does not swell even when it comes into contact with oils and fats, solvents, plasticizers, and the like contained in ink.

Japanese Patent Application Laid-Open No. 2007-139062

An object of the present invention is to provide a toothed conveying belt that has high flexibility, low belt bending resistance, and excellent swelling resistance.

The configuration of the present invention for solving the above problems is as follows.
1. having a belt body and a tension member embedded in the belt body,
The belt main body is made of a rubber composition mainly composed of a rubber component containing NBR and EPDM at a mass ratio of 75/25 to 50/50,
A toothed belt for conveying, characterized in that the bending rigidity of the belt per 6 mm of belt width is 0.080 N·cm ² or less.
2. 1. The back surface friction coefficient (against PPC paper) is 0.6 or more. Toothed belt for transportation according to .
3. 1. The belt body has a Wallace rubber hardness of 60° or more. or 2. Toothed belt for transportation according to .
4. 1. The rubber composition contains a plasticizer. ~3. A toothed belt for conveyance according to any one of .
5. 1. It is used for conveying paper sheets. ~ 4. A toothed belt for transportation according to any one of .

Since the toothed belt for conveyance of the present invention has high flexibility and low belt bending resistance, the degree of freedom of the belt layout is high, and the starting torque of the power source can be reduced, so that the entire apparatus can be labor-saving. Miniaturization can be achieved. The toothed conveying belt of the present invention is excellent in swelling resistance and can carry out accurate conveying over a long period of time. The toothed belt for conveying of the present invention can be suitably used as a toothed belt for conveying paper sheets, which is incorporated in an electrophotographic apparatus, an automatic vending machine, a change machine, a ticket vending machine, a banknote conveying apparatus, and the like.

The figure which shows the toothed belt for conveyance which is an example of one embodiment of this invention.

The toothed conveyor belt of the present invention is
having a belt body and a tension member embedded in the belt body,
The belt body is made of a rubber composition mainly composed of a rubber component containing NBR and EPDM at a mass ratio of 75/25 to 50/50,
The bending rigidity of the belt per 6 mm of belt width is 0.080 N·cm ² or less.
In this specification, the description of A to B (A and B are numerical values) means a numerical range including A and B, that is, from A to B and below.

FIG. 1 shows a conveying toothed belt 10 that is an embodiment of the present invention.
The conveying toothed belt 10 has a core wire 12 embedded as a tensile member in the belt body 11 so as to form a spiral with a constant pitch in the width direction of the belt. It is partitioned into 11a and tooth rubber portion 11b. Further, the toothed belt 10 for conveyance is covered with a reinforcing cloth 13 on the tooth rubber portion 11b side surface, and tooth portions 14 are formed by covering the tooth rubber portion 11b with the reinforcing cloth 13 .

The shape of the conveying toothed belt 10 can be adjusted according to its use. 0 to 3.0 mm, and the tooth pitch is 2.032 to 5.080 mm. The tooth portion 14 has, for example, a tooth portion height of 0.5 to 2.0 mm and a tooth portion width of 0.7 to 1.4 mm at the tip portion of the tooth portion. The cross-sectional shape of the tooth portion 14 is not particularly limited, and may be, for example, trapezoidal or semicircular.

The conveyor toothed belt 10 has a belt bending rigidity of 0.080 N·cm ² or less per belt width of 6 mm. If the flexural rigidity of the toothed belt for conveyance satisfies this value, the starting torque of the power source can be reduced, and the labor saving and miniaturization of the entire apparatus can be realized. This bending rigidity is more preferably 0.075 N·cm ² or less, and even more preferably 0.070 N·cm ² or less.

Here, the toothed belt bending rigidity for conveyance is a value calculated by multiplying the bending stiffness E of the toothed belt for conveyance by the geometrical moment of inertia I of the toothed belt for conveyance. For example, the bending stiffness E is obtained by a bending test using an Olsen bending tester according to JIS K7106. The geometrical moment of inertia I is obtained by I=bh ³ /12, where b is the belt width and h is the belt thickness at the root portion.

The transfer toothed belt 10 preferably has a back friction coefficient (against PPC paper) of 0.6 or more. It is preferable that the back surface friction coefficient (against PPC paper) is 0.6 or more, because the banknotes can be conveyed at a stable speed. The coefficient of back surface friction (against PPC paper) of the toothed conveying belt 10 is more preferably 0.65 or more, and even more preferably 0.7 or more.

It is preferable that the toothed belt 10 for conveyance has a Wallace rubber hardness of 60° or more in the main body 11 of the toothed belt. When the Wallace rubber hardness is such a value, the adhesion abrasion resistance is excellent. The Wallace rubber hardness of the toothed belt main body 11 is more preferably 62° or more, and even more preferably 65° or more. Also, it is preferably 75° or less, more preferably 72° or less.

The belt body 11 is made of a rubber composition whose main component is a rubber component containing NBR and EPDM in a mass ratio of 75/25 to 50/50. The toothed belt for conveyance of the present invention is excellent in swelling resistance because the belt main body (rubber composition) contains this rubber component as a main component. Here, to be the main component means to contain 80% by mass or more, and the belt body (rubber composition) can contain additives and the like.

・Nitrile rubber (NBR)
NBR is a copolymer of acrylonitrile and 1,3-butadiene. The composition ratio of acrylonitrile and 1,3-butadiene can be appropriately adjusted according to workability and desired physical properties. For example, from the viewpoint of swelling resistance and cold resistance, the acrylonitrile content is preferably 12% by mass or more and 45% by mass or less, more preferably 30% by mass or more and 40% by mass or less. NBR can also be used singly or in combination of two or more.

・Ethylene propylene diene rubber (EPDM)
EPDM is a ternary copolymer of ethylene, propylene and a diene. The composition ratio of ethylene and propylene can be appropriately adjusted according to workability and desired physical properties. For example, from the viewpoint of cold resistance, it is preferable that the content of ethylene is 40% by mass or more and 58% by mass or less. Dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 1,4-hexadiene (1,4-HD) and the like can be used as the diene component. Among these, those having an ENB content of 4% by mass or more and 12% by mass or less are preferable because they have high elasticity. One type of EPDM or a mixture of two or more types of EPDM can be used.

The rubber composition of the present invention contains NBR and EPDM in a weight ratio of 75/25 to 50/55. By setting the thickness within this range, various physical properties required for the toothed belt for conveyance can be exhibited in a well-balanced manner. The weight ratio between NBR and EPDM is preferably 70/30 to 55/45. Moreover, for applications requiring cold resistance, the acrylonitrile content in the rubber composition is preferably 26% by mass or less.

- Plasticizer The rubber composition of the present invention preferably contains a plasticizer. Since NBR and EPDM are not compatible with each other, a rubber composition in which NBR and EPDM are mixed (kneaded) forms a sea-island structure. When a large force is applied to a rubber product using this rubber composition, cracks tend to occur starting at the interface of the sea-island structure (heterogeneous polymer). , and the strength is further reduced.
A decrease in tensile strength can be suppressed by adding a plasticizer to the rubber composition containing NBR and EPDM. Although the detailed mechanism is unknown, the applicant speculates that this is because the plasticizer gathers at the interface of the sea-island structure formed by NBR and EPDM and functions to bind the two together.

The plasticizer is not particularly limited as long as it exhibits the effects of the present invention. Examples include ester-based, polyester-based, and petroleum-based softeners such as naphthenic, aromatic, and paraffin-based softeners. Examples of phthalate esters include dibutyl phthalate (DBP), di(2-ethylhexyl) phthalate (DOP), and diisononyl phthalate (DINP). Examples of aliphatic dibasic esters include di(2-ethylhexyl). ) adipate (DOA), dibutyl sebacate (DBS), di(2-ethylhexyl) sebacate (DOS), etc., trimellitic acid esters such as tri-2-ethylhexyltothimellitate (TOTM), tridecyl trimellitate Examples of ether esters such as (TDTM) include adipate ether esters, and examples of polyesters include adipate polyester and sebacate polyester. Commercially available products can also be used. For example, as a polyether ester type, Adekasizer RS-700, RS-735, RS-966, RS-1000, etc. can be used.
In the present invention, the blending amount of the plasticizer is not particularly limited as long as the effect of the present invention is exhibited, but it is preferably 3% by mass or more, more preferably 5% by mass or more, based on 100% by mass of the rubber component. Moreover, the upper limit of this compounding amount is about 25% by mass or less. Even if the plasticizer is blended more than this, the effect is saturated and the performance is hardly improved, and bleeding may occur on the rubber surface, and the cost is increased.

Cross-linking agent As a cross-linking agent for cross-linking the rubber component, organic peroxides, sulfur, and these can be used in combination. Further, the rubber component may be crosslinked by using an electron beam or the like. Among these, from the viewpoint of wear resistance, it is preferable to use an organic peroxide. Specifically, di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, α, α '-bis(t-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyldi(t-butyl)hexyne, 2, 5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxyisopropyl carbonate, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane and the like. One or more of these organic peroxides can be used in combination. The blending amount of the organic peroxide is usually, for example, about 1% by mass or more and 8% by mass or less with respect to 100% by mass of the rubber component.

Crosslinking aid Crosslinking aids include, for example, tetrahydrofurfuryl methacrylate, ethylene dimethacrylate, 1,3-butylene dimethacrylate, 1,4-butylene dimethacrylate, 1,6-hexanediol dimethacrylate, and polyethylene glycol dimethacrylate. , 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 2,2′-bis(4-methacryloxydiethoxyphenyl)propane, 2,2′-bis(4-acryloxydiethoxyphenyl ) Propane, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, 3-chloro-2-hydroxypropyl methacrylate, oligoester acrylate, aluminum methacrylate, zinc methacrylate, magnesium dimethacrylate, calcium dimethacrylate, triallyl isocyanurate, triallyl cyanurate, triallyl trimellitate, diallyl phthalate, diallylchlorendate, divinylbenzene, 2-vinylpyridine, N,N'-methylenebisacrylamide, p-quinonedioxin, p,p'-di benzoylquinine dioxin, 1,2-polybutadiene, dipentamethylenethiuram tetrasulfide and the like. The cross-linking aid can be used alone or in combination of two or more of these. Among these, sulfur is preferred because it facilitates setting the bending rigidity of the belt and the Wallace rubber hardness within the scope of the present invention. The amount of the cross-linking aid added is about 0.1% by mass or more and 3.0% by mass or less with respect to 100% by mass of the rubber component.

Inorganic particles The rubber composition contains one or more inorganic particles such as silica, carbon black, titanium oxide, aluminum oxide, calcium carbonate, magnesium carbonate, zinc carbonate, barium sulfate, diatomaceous earth, clay, talc, and zinc oxide. can include In a rubber composition containing NBR and EPDM, inorganic particles tend to gather at the interface of the sea-island structure formed by NBR and EPDM, which tends to reduce the strength at the interface. Since the rubber composition of the present invention is excellent in strength at the interface of the sea-island structure formed by NBR and EPDM, it is possible to reduce the decrease in strength even when inorganic particles are blended. The amount of the inorganic particles to be blended is preferably 10% by mass or more, more preferably 20% by mass or more, relative to 100% by mass of the rubber component. Moreover, the upper limit of this compounding amount is preferably 100% by mass or less, and more preferably 90% by mass or less. As the inorganic particles, it is preferable to use carbon black from the viewpoints of imparting conductivity, reinforcing properties, and preventing ultraviolet deterioration. Carbon black to be blended is not particularly limited, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT thermal black such as;

The rubber composition of the present invention also contains a processing aid, vulcanization accelerator, vulcanization accelerator aid, anti-aging agent, anti-scorch agent, ultraviolet absorber, light stabilizer, softener, foaming agent, and foaming aid. , lubricants, flame retardants, antistatic agents, colorants, and the like.
Processing aids include, for example, stearic acid, polyethylene wax, metal salts of fatty acids, and the like. 1 type(s) or 2 or more types can be used for a processing aid among these. The content of the processing aid is, for example, 0.5% by mass or more and 2% by mass or less with respect to 100% by mass of the rubber component.
Examples of vulcanization accelerators include thiuram-based (e.g., TETD, TT, TRA, etc.), thiazole-based (e.g., MBT, MBTS, etc.), sulfenamide-based (e.g., CZ, etc.), dithiocarbamate-based (e.g., BZ-P etc.). One or more of these vulcanization accelerators can be used. The content of the vulcanization accelerator is, for example, 2% by mass or more and 5% by mass or less with respect to 100% by mass of the rubber component.

Examples of vulcanization acceleration aids include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof. One or two or more of these can be used as vulcanization accelerators. The content of the vulcanization accelerator aid is 3% by mass or more and 7% by mass or less with respect to 100% by mass of the rubber component.
Anti-aging agents include, for example, amine-ketone-based anti-aging agents, diamine-based anti-aging agents, and phenol-based anti-aging agents. Anti-aging agent can use 1 type(s) or 2 or more types among these. The content of the antioxidant is 0.1% by mass or more and 5% by mass or less with respect to 100% by mass of the rubber component.

The core wire 12 is, for example, a fiber bundle of glass fibers immersed in an RFL liquid (resorcin-formalin-latex aqueous solution) and heat-treated to form a twisted yarn, or a twisted yarn of aramid fibers immersed in an RFL liquid. A heat-treated wire rope, a wire rope immersed in rubber paste and then heat-treated, or the like can be used. The core wire made of glass fiber or aramid fiber may be heat-treated after being immersed in rubber paste. The cords have, for example, an outer diameter of 0.1 to 0.4 mm and a pitch in the belt width direction of 0.1 to 0.7 mm.

The reinforcing cloth 13 is, for example, a cloth made of nylon fiber or aramid fiber (such as a twill cloth) that is soaked in rubber cement and then heat-treated, or a paste-like material that is applied to the surface of the toothed belt main body. A material coated with rubber paste or the like can be used. The reinforcing fabric has a thickness of, for example, 0.1-0.7 mm.
The reinforcing fabric preferably has a tensile strength of 300 N/3 cm or more in the warp direction (belt width direction) and 80% or more of the warp strength in the weft direction (belt circumferential direction). Moreover, it is preferable that the elongation rate in the weft direction is three times or more that in the warp direction.

The toothed conveyor belt of the present invention can be manufactured by a known manufacturing method.
The use of the toothed conveying belt of the present invention is not particularly limited. , ticket vending machines, bill conveying devices, etc., and can be suitably used as toothed belts for conveying paper sheets for conveying printed matter, bills, and the like.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.
"Example 1"
NBR (manufactured by JSR, N230S) 70 parts by weight, EPDM (manufactured by Dow Chemical Co., Nordel IP4640) 30 parts by weight, polyether ester plasticizer (Adekasizer RS700 manufactured by ADEKA) 10 parts by weight, carbon black FEF (Tokai Carbon Co., Ltd., trade name: Siest SO) 60 parts by mass, stearic acid 1 part by mass, zinc oxide 5 parts by mass, a cross-linking agent (manufactured by NOF Corporation, Peroximone F-40) 5 parts by mass, are mixed with a closed kneader. The uncrosslinked rubber composition obtained by kneading was formed into a sheet with a roll, and press-molded at 170° C. for 20 minutes to prepare crosslinked rubber sheets with a thickness of 1 mm and a thickness of 2 mm.

"Example 2"
A crosslinked rubber sheet was prepared in the same manner as in Example 1, except that 60 parts by mass of NBR and 40 parts by mass of EPDM were used.
"Example 3"
A crosslinked rubber sheet was prepared in the same manner as in Example 1, except that 55 parts by mass of NBR and 45 parts by mass of EPDM were used.

"Comparative Example 1"
A crosslinked rubber sheet was prepared in the same manner as in Example 1, except that 80 parts by mass of NBR, 20 parts by mass of EPDM, 5 parts by mass of polyether ester plasticizer, and 6.5 parts by mass of cross-linking agent were used.
"Comparative Example 2"
A crosslinked rubber sheet was prepared in the same manner as in Example 4, except that 40 parts by mass of NBR and 60 parts by mass of EPDM were used.

The obtained crosslinked rubber sheet was evaluated as follows. Table 1 shows the results.
·Rubber hardness According to JIS K6253-3:2012, the hardness was measured with a type A durometer in a state in which three crosslinked rubber sheets with a thickness of 2 mm were stacked.
- Tensile strength and elongation at break According to JIS K6251:2010, the tensile strength (TB) and elongation at break (Eb) of a crosslinked rubber sheet having a thickness of 2 mm were measured.
・ Gameman twist (t100)
According to JIS K6261, t100 (the temperature at which the torsional rigidity becomes 100 times the value at 23° C.) was measured by a Gehman torsional test. Measurement was performed using a sample obtained by punching a 2 mm thick crosslinked rubber sheet into a 3 mm wide strip.

（ただし、ΔＶ_１００は体積変化率、ｍ_１は浸漬前の空気中での質量、ｍ_２は浸漬前の水中での質量（重りの質量を加算）、ｍ_３は浸漬後の空気中での質量、ｍ_４は浸漬後の水中での質量（重りの質量を加算）、ｍ_５は重りの水中での質量を表す） - Swelling resistance A test piece obtained by cutting a 2 mm thick crosslinked rubber sheet into a 3 cm square was immersed in linseed oil (Sankei Sangyo Co., Ltd.) at 80°C for 24 hours. After that, the surface of the taken-out test piece was thoroughly wiped with a rag, the mass in air and the mass in water were measured, and the volume change rate before and after immersion was determined by the following formula (1).
(Formula 1)

(However, ΔV ₁₀₀ is the volume change rate, m ₁ is the mass in air before immersion, m ₂ is the mass in water before immersion (adding the mass of the weight), and m ₃ is the mass in air after immersion. mass, m ₄ is the mass in water after immersion (adding the mass of the weight), m ₅ represents the mass of the weight in water)

・Ozone resistance: A test piece punched out from a 1mm thick crosslinked rubber sheet to a width of 10mm and a length of about 40mm was wrapped around a φ8mm stainless steel round bar without any slack, and placed in a tank with an ozone concentration of 50pphm and a temperature of 40°C. After 2, 4, 24 hours, and thereafter every 24 hours until 336 hours, the test piece was visually observed for cracks.

The rubber compositions of Examples 1 to 3 were excellent in swelling resistance and further excellent in ozone resistance.
On the other hand, the rubber composition of Comparative Example 1 was excellent in swelling resistance but inferior in ozone resistance, and the rubber composition of Comparative Example 2 was inferior in swelling resistance.

Using the rubber composition of Example 2, a toothed conveying belt was produced.
The conveying toothed belt had a belt circumference length of 150 mm, a belt width of 6 mm, a belt thickness of 1.1 mm, and a tooth pitch of 2.032 mm. The tooth height was 0.51 mm, and the width of the tip of the tooth was 0.76 mm. , styrene-butadiene-vinylpyridine terpolymer latex RFL solution (resorcin-formalin-latex aqueous solution), heat treatment, twisted yarn, and spiral winding was used. As the reinforcing fabric, a 6,6 nylon twill fabric is immersed in a styrene-butadiene-vinylpyridine terpolymer latex RFL solution (resorcin-formalin-latex aqueous solution) and subjected to heat treatment. was used.

The following evaluations were performed on the obtained toothed belt for transportation.
Bending Stiffness Bending stiffness E of the obtained toothed belt for transportation was determined by a bending test using an Olsen bending tester according to JIS K7106. The length of the test piece is 7 cm, the width b of the test piece is 6 mm, the thickness h of the test piece is the thickness of the belt at the root portion of 1.1 mm, and the distance S between the struts is 1.27 cm. The pendulum moment M at 100% load scale was 0.002648 N·m, and the bending angle Φ was 50π/180 rad. The measurement was performed under conditions of temperature of 23±2° C. and humidity of 50±5%.
The bending stiffness E was multiplied by the geometrical moment of inertia I of the conveyor toothed belt to calculate the belt bending rigidity. The moment of inertia I of area can be obtained by I=bh ³ /12.

<Wallace rubber hardness>
The Wallace rubber hardness of the belt outer surface of the conveying toothed belt body was measured using a Wallace rubber hardness tester (Wallace, Model No. H12/1).
<Coefficient of back surface friction (against PPC paper)>
Regarding the coefficient of friction on the back surface of the toothed belt for transportation, a Haydon type friction wear test (Shinto Kagaku Co., Ltd., TYPE: 14FW) was used. The speed was measured at 100 mm/min.

Table 2 shows the results.

Since the toothed belt for conveyance of the present invention is flexible and has a low belt bending resistance, it is less likely to break even if it is wound around in a complicated layout via a large number of pulleys, and can be used for a long period of time. can. In addition, this toothed belt for transportation has a coefficient of friction sufficient for transportation. Furthermore, since the toothed belt for transportation has excellent swelling resistance and ozone resistance, it can be suitably used for transportation of bills, tickets, printed matter, and the like, which contain oil, solvents, plasticizers, and the like. .

10 toothed belt for conveyance 11 belt main body 11a back rubber portion 11b tooth rubber portion 12 core wire 13 reinforcing cloth 14 tooth portion

Claims (5)

having a belt body and a tension member embedded in the belt body,
The belt main body is made of a rubber composition mainly composed of a rubber component containing NBR and EPDM at a mass ratio of 75/25 to 50/50,
A toothed belt for conveying, characterized in that the bending rigidity of the belt per 6 mm of belt width is 0.080 N·cm ² or less. 2. The toothed conveying belt according to claim 1, wherein the back surface friction coefficient (against PPC paper) is 0.6 or more. 3. The toothed conveying belt according to claim 1, wherein said belt body has a Wallace rubber hardness of 60[deg.] or more. The toothed conveying belt according to any one of claims 1 to 3, wherein the rubber composition contains a plasticizer. The toothed belt for conveying according to any one of claims 1 to 4, characterized in that it is used for conveying paper sheets.

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