KR101425297B1 - Rope for elevator - Google Patents

Abstract

The rope for an elevator according to the present invention comprises a rope body and an outer periphery of the rope body and is provided with a thermoplastic polyurethane elastomer and a friction stabilizer having a melting point of 100 캜 or higher and 150 캜 or lower, and an isocyanate compound having two or more isocyanate groups in one molecule And a resin coating layer composed of a molded product of the resin coating layer-forming composition. In order to further stabilize the friction coefficient, the inorganic filler may be further mixed into the resin coating layer forming composition. The elevator rope of the present invention has a stable coefficient of friction irrespective of the temperature or the sliding speed.

Description

[0001] ROPE FOR ELEVATOR [0002]

The present invention relates to an elevator rope used in an elevator to hang an elevator car.

Conventionally, in an elevator apparatus, a sheave having a diameter of 40 times or more the diameter of the rope is used to prevent premature wear and disconnection of the rope. For this reason, in order to reduce the diameter of the sheave, it is necessary to reduce the diameter of the rope. However, if the rope diameter is reduced without changing the number of ropes, the strength of the rope is lowered and the loadable weight of the elevator may be lowered. In addition, the increase in the number of ropes complicates the configuration of the elevator apparatus. Further, if the diameter of the drive sheave is made small, the bending fatigue life of the rope becomes short, and it is necessary to frequently replace the rope.

As means for solving these problems, a plurality of stranded wires are twisted to form a strand, a plurality of strands are twisted to form a wire rope, and an outermost periphery of the wire rope It has been proposed to use a rope covered with a resin material (see, for example, Patent Document 1). Such an elevator using a rope is driven by the frictional force between the sheave and the resin material constituting the outermost periphery of the rope. For this reason, it is required to stabilize or improve the friction characteristics of the resin material. In order to improve the friction characteristics of the elevator rope, it has been proposed to use a rope covered with a polyurethane covering material not containing wax (see, for example, Patent Document 2). On the other hand, in order to reduce the coefficient of friction between the sheave and the belt to within a predetermined range, it is preferable to use a flat sheet coated with isoparaffin wax having a low content in a polyether-based thermoplastic polyurethane elastomer A flat belt has been proposed (see, for example, Patent Document 3). In addition, in order to obtain a rope and a belt in which the coefficient of friction does not drop significantly even when oil is likely to adhere to the contact surface between the sheave and the rope or the belt and the wear of the resin covering body due to sliding is small, (See, for example, Patent Document 4 (Japanese Unexamined Patent Publication (Kokai) No. 2003-241254), a solid lubricant additive is added to a solid lubricant additive, Reference).

Generally, it is known that the coefficient of friction of a resin material largely depends on the sliding speed and the temperature. It is also known that viscoelastic properties such as dynamic viscoelasticity of a resin material have a conversion property (Williams-Landel-Ferry formula (WLF formula)) between the speed and the temperature dependency. Furthermore, it is known that the viscoelastic characteristics of the rubber are related to the friction characteristics of the rubber because the same conversion properties are established with respect to the sliding speed and the temperature even in the case of friction of the rubber (see, for example, Non-Patent Document 1 Reference).

Patent Document 1: JP-A-2001-262482 Patent Document 2: Japanese Patent Application Laid-Open No. 2004-538382 Patent Document 3: International Publication No. 2007/128622 Patent Document 4: JP-A-2009-234791

Non-Patent Document 1: Grosch, K. A .: Proc. Roy. Soc., A 274, 21 (1963)

As can be seen from the above, even in the case of the polyurethane covering material not containing the wax described in Patent Document 2, since the coefficient of friction of the material itself varies depending on the sliding speed and temperature, there is a problem that the elevator can not be stably braked there was. In addition, as described in Non-Patent Document 1, the friction coefficient of rubber has a maximum value with respect to the sliding speed. In order to stop the elevator for a long time, it is necessary to maintain the state of the car with a friction force between the rope and the sheave. However, the covering material having a large fluctuation coefficient of friction as in the past and the content as described in Patent Document 3 A coating material to which low isoparaffin wax is added has a problem that the coefficient of friction at a minute sliding speed can not be secured to a certain level or more and that the stop position of the car is shifted with time . In order to make an emergency stop or sudden stop of the elevator while driving, it is necessary to brak the elevator by the frictional force between the rope and the sheave. However, in the conventional cover materials described in Patent Documents 1 to 4, So that there is a problem that the friction coefficient between the rope and the sheave is remarkably lowered as a result.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an elevator rope having a stable coefficient of friction irrespective of temperature or sliding speed.

The inventors of the present invention have studied the composition of the resin material and found that in order to obtain an elevator rope having a small fluctuation in the coefficient of friction even at a wide range of sliding speeds at the time of holding the suspension for a long period of time A resin material in which a friction modifier having a melting point of not lower than 100 ° C and not higher than 150 ° C and an isocyanate compound having two or more isocyanate groups in one molecule are added to a polyurethane elastomer as a coating layer of a rope body And finding a useful one, thereby completing the present invention.

According to the present invention, a molded article of a resin coating layer-forming composition comprising a thermoplastic polyurethane elastomer and a friction modifier having a melting point of not less than 100 DEG C and not more than 150 DEG C and an isocyanate compound having two or more isocyanate groups in one molecule is added to the outer periphery of the rope body It is possible to obtain an elevator rope having a stable coefficient of friction without depending on temperature or sliding speed.

Fig. 1 is an example of a result (a viscoelastic master curve) showing the frequency dependence of the loss elastic modulus in the material in which the sliding speed dependence of the friction coefficient is different.
2 is a conceptual diagram of an apparatus for measuring a coefficient of friction in a minute slip velocity region (speed region) used in the embodiment.
3 is a conceptual diagram of an apparatus for measuring the friction coefficient at the time of emergency stop used in the embodiment.

Hereinafter, an embodiment of the present invention will be described.

Embodiment 1

The rope for an elevator according to Embodiment 1 of the present invention is characterized in that the outer periphery of the rope body is made of a thermoplastic polyurethane elastomer and a friction stabilizer having a melting point of not lower than 100 캜 and not higher than 150 캜 and an isocyanate group isocyanate group) having at least two isocyanate groups in the resin-coated layer forming composition. The reason why the friction coefficient is stable without depending on the temperature or the sliding speed is that the friction stabilizer is not melted and the friction coefficient is lowered under the sliding condition in which the generation of frictional heat is small when the elevator is kept stationary or during normal operation However, under a sliding condition in which a sliding speed is high as in the case of an emergency stop at an elevator (abrupt stop) and a significant frictional heat is likely to occur, the friction stabilizer melts and the lubricity of the resin covering layer increases sharply, As a result, it is considered that the strength of the resin coating layer is not reduced or melted, and damage due to friction is suppressed, and a friction coefficient of at least a certain level can be ensured.

Examples of the thermoplastic polyurethane elastomer used in the present embodiment include ester-based thermoplastic polyurethane elastomer, ether-based thermoplastic polyurethane elastomer, ester-ether-based thermoplastic polyurethane elastomer, and carbonate-based thermoplastic polyurethane elastomer . These may be used alone or in combination of two or more.

Among these thermoplastic polyurethane elastomers, it is preferable to use an ether-based thermoplastic polyurethane elastomer in order to prevent hydrolysis caused in the use environment. In consideration of the flexibility and durability of the elevator rope, JIS A hardness (type specified in JIS K7215 A hardness by durometer) of not less than 85 and not more than 95 is more preferably used as the polyether-based thermoplastic polyurethane elastomer.

In addition, it is preferable to use a thermoplastic polyurethane elastomer processed in a pellet form for the purpose of handling such as mixing of a friction stabilizer and an isocyanate compound having two or more isocyanate groups in one molecule.

Examples of the friction stabilizer having a melting point of 100 캜 or higher and 150 캜 or lower used in the present embodiment include waxes such as paraffin wax, microcrystalline wax and low molecular weight polyolefin wax, fatty acid amides, polyethylene Or a polyolefin resin such as polypropylene is used. Of these, an olefin-based compound is preferable in order to reduce the fluctuation of the coefficient of friction at the time of stopping and holding.

When the melting point of the friction stabilizer is less than 100 캜, there is a possibility that the coefficient of friction of the rope surface under an environment having a high atmospheric temperature such as summer is extremely low, particularly under a sliding condition where the sliding speed is very low, . On the other hand, when the melting point of the friction stabilizer is more than 150 캜, the melting of the friction stabilizer and the resulting lubrication are slowed under sliding conditions under which significant frictional heat is likely to occur, and the strength or melting of the resin covering layer is lowered, There is a risk of degradation.

The addition amount of the friction stabilizer is not particularly limited, but is preferably 0.5% by weight or more and 5% by weight or less, and more preferably 1% by weight or more and 3% by weight or less, with respect to the resin coating layer forming composition. If the addition amount of the friction stabilizer is less than 0.5% by weight, the resin coating layer having a stable coefficient of friction may not be obtained. On the other hand, if the content exceeds 5% by weight, the strength, abrasion resistance and adhesiveness of the covering material may deteriorate, Flexibility and durability may be impaired.

Examples of the isocyanate compound having two or more isocyanate groups in one molecule used in the present embodiment include 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate diisocyanate, lysine methlyester diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 1,5-octylene diisocyanate, Aliphatic isocyanates such as dimer acid diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hydrogenated diisocyanate, Tolylene diisocyanate (h (alicyclic) isocyanates such as methyl cyclohexane diisocyanate, isopropylidene dicyclohexyl-4, and 4'-diisocyanate, 2, 4 - or 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, Triphenylmethane triisocyanate, tris (4-phenyl isocyanate), thiophosphate, tolidine diisocyanate, p-phenylene diisocyanate ), Diphenylether diisocyanate, diphenylsu < RTI ID = 0.0 > diisocyanate and aromatic (isocyanate) isocyanates such as lfone diisocyanate. These may be used alone or in combination of two or more. An isocyanate prepolymer having an isocyanate group at the molecular end obtained by reacting the above isocyanate with an active hydrogen compound such as polyol or polyamine is used as an isocyanate compound having two or more isocyanate groups in one molecule It can also be used. These isocyanate compounds exhibit an effect of stabilizing the friction coefficient with respect to the temperature and the sliding speed. The isocyanate compound is a resin composition which is preliminarily mixed with a thermoplastic resin having insufficient reactivity with an isocyanate compound other than the thermoplastic polyurethane elastomer and processed into pellets (hereinafter referred to as " isocyanate arrangement (sometimes referred to as " batch "). Examples of the thermoplastic resin other than the thermoplastic polyurethane elastomer used herein include epoxy resins, polystyrene resins, polyvinyl chloride resins, polyvinyl acetate resins, ethylene-vinyl acetate copolymer resins, polyethylene resins, polypropylene resins, Resins and the like.

The amount of these isocyanate compounds to be added may be appropriately adjusted within a range in which the JIS A hardness of the resulting molded article is 98 or less and the glass transition temperature is -20 占 폚 or less.

The resin coating layer in the present embodiment is usually prepared by mixing the above-described thermoplastic polyurethane elastomer pellets with the above-mentioned friction stabilizer and isocyanate compound (or isocyanate arrangement), and then putting the mixture into a molding machine such as an extrusion molding machine or an injection molding machine , And molding.

In order to stabilize the friction coefficient with respect to the temperature and the sliding speed, the resin coating layer forming composition may further be mixed with an inorganic filler. Examples of such inorganic fillers include spherical inorganic fillers such as calcium carbonate, silica, titanium oxide, carbon black, acetylene black and barium sulfate, fibrous inorganic fillers such as carbon fibers and glass fibers, Mica, talc, bentonite, and the like can be mentioned. These may be used alone or in combination of two or more. Among them, it is preferable to use a fibrous inorganic filler and a plate-like inorganic filler in order to further reduce the fluctuation of the coefficient of friction. The hardness of these inorganic fillers is not particularly limited. The amount of these inorganic fillers to be added is appropriately adjusted within a range in which the JIS A hardness of the resulting molded article is 98 or less and the glass transition temperature is -20 占 폚 or less.

The reason why the JIS A hardness of the molded product is specified to be 98 or less is as follows. When it is more than 98, the flexibility of the rope is impaired and the power consumption tends to increase when the rope is applied to an elevator. Because. The JIS A hardness of the molded article is more preferably 85 or more and 95 or less.

The reason why the glass transition temperature of the molded article is specified to be -20 占 폚 or less is that the higher the glass transition temperature of the molded article is, the smaller the friction coefficient depends on the sliding speed. On the other hand, the higher the glass transition temperature of the molded article, When the rope is applied to an elevator rope as a resin coating layer, the flexibility of the rope deteriorates. If the rope is repeatedly bent under an environment higher than the glass transition temperature of the formed article, the stress applied by the resin covering layer causes cracks The inventors of the present invention have found out that fatigue failure tends to occur easily. The glass transition temperature of the molded article is more preferably -25 占 폚 or less.

Since the elevator rope according to the present embodiment is characterized by the resin material of the outermost layer covering the outer periphery of the rope body, the structure of the rope body is not particularly limited, but the rope body generally has a plurality As a load supporting member. The rope main body in the present embodiment may be a belt-shaped rope including the above strands or cord. In order to improve the adhesion between the rope body and the resin coating layer, an adhesive for metals and polyurethane such as Chemlok (registered trademark) 218 (manufactured by LORD Far East Co., Ltd.) Or it is preferable to apply it to the cord in advance.

According to the present embodiment, the variation of the friction coefficient is small at a wide range of sliding speeds from the minute sliding speed range required for holding the elevator car to the stopped state to the large sliding speed range when the elevator is stopped or stopped rapidly during driving An elevator rope can be obtained.

The present embodiment has been described as applied to an elevator rope, but the present invention is equally applicable to an elevator belt.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

≪ Examples 1 to 11 >

A friction stabilizer and, if necessary, an inorganic filler were added to an ether-based thermoplastic polyurethane elastomer having a JIS A hardness of 95 (hereinafter, sometimes briefly referred to as "TPU"), and then processed into a pellet. A predetermined amount of isocyanate pellets obtained by kneading 1.85 parts by mass of a polystyrene resin, 1.3 parts by mass of an epoxy resin and 1.85 parts by mass of 4, 4'-diphenylmethane diisocyanate with a biaxial extruder was added to this pelletized resin composition, The resulting mixture was fed to an extrusion molding machine to form a resin coating layer covering the outer periphery of the rope body. After covering the rope body with the resin coating layer, the rope body was heated at 100 占 폚 for 2 hours for hardening of the adhesive agent and annealing treatment of the resin covering layer to obtain a rope for an elevator having a diameter of 12 mm. The elevator rope thus obtained has the sectional structure shown in Fig. 1 of International Publication No. 2003/050348. The rope body includes an inner layer rope having a plurality of core strands each having a plurality of steel wire strands twisted each other and a plurality of inner layer strands each having a plurality of steel wire strands twisted together, Layered rope provided on the outer periphery of the inner layer covering body and having a plurality of outer layer strands each having a plurality of forced strands twisted with each other, And corresponds to a covering body. Before the rope body was covered with the resin coating layer, the outer circumferential strands of the rope body were coated with Chemlock (registered trademark) 218 (manufactured by LORD Far East Co., Ltd.) and dried. The composition of the resin coating layer is shown in Table 1.

≪ Comparative Examples 1 and 7 to 9 >

The inorganic filler was added to the TPU, if necessary, and then processed into a pellet. An elevator rope was obtained in the same manner as in Example except that this pelletized resin composition was used as a resin covering layer covering the outer periphery of the rope body. The composition of the resin coating layer is shown in Table 2.

≪ Comparative Examples 2 to 6 and 10 to 12 >

TPU was added with a friction stabilizer or an inorganic filler and then processed into pellets. A predetermined amount of isocyanate pellets obtained by kneading 1.85 parts by mass of a polystyrene resin, 1.3 parts by mass of an epoxy resin and 1.85 parts by mass of 4, 4'-diphenylmethane diisocyanate with a biaxial extruder was added to this pelletized resin composition, A rope for an elevator was obtained in the same manner as in Example except that it was thoroughly mixed as a resin covering layer covering the outer periphery of the rope body. The composition of the resin coating layer is shown in Table 2.

(Measurement of Glass Transition Temperature (Tg) of Resin Coating Layer)

The glass transition temperature (Tg) of the resin coating layer was measured as follows. A molding composition having the same composition as the resin coating layer used in each of Examples and Comparative Examples was supplied to an injection molding machine and molded into a flat plate of 100 mm x 100 mm x 2 mm thick and heated at 100 DEG C for 2 hours, A specimen of 10 mm thickness 2 mm was cut out. The measurement was performed using a viscoelastic spectrometer DMS1200 manufactured by Seiko Instruments Inc. under the conditions of a deformation mode: a bending mode, a measuring frequency of 10 Hz, a temperature raising rate of 2 ° C./minute, and an excitation amplitude of 10 μm , The loss elastic modulus of the test piece was measured, and the peak temperature of the loss elastic modulus was taken as Tg.

(JIS A Hardness of Resin Coating Layer)

According to JIS K7215, durometer A hardness was measured using a Type A durometer.

(Measurement of Rope Friction Coefficient)

(1) Measurement method at the microslip speed and the normal operation sliding speed

2 is a conceptual diagram of an apparatus for measuring a coefficient of friction at a minute sliding speed region. As shown in Fig. 2, the elevator rope 1 obtained in the examples and the comparative example was wound 180 degrees with respect to the sheave 2, one end thereof was fixed to the measuring device 3, , And the elevator rope 1 was tensioned. Here, when the sheave 2 is rotated clockwise at a predetermined speed, the rope tension T ₂ on the fixed side is loosened by the frictional force generated between the elevator rope 1 and the sheave 2, And the rope tension T ₁ on the side of the rope tension T ₁ . The rope tension T ₁ and the rope tension T ₂ on the fixed side of these speculations were measured by the load cell provided at the connection portion between the rope and the weight. T ₁ and T ₂ (where T ₁ > T ₂ ) and the rope contact angle θ (= 180 mm) are defined as 1 × 10 ^-5 mm / sec and 1 mm / sec, respectively, , Coefficient K ₂ (= 1.19) determined in the shape of the sheave groove was substituted into the following equation ₁ to obtain the friction coefficient μ ₁ between the elevator rope 1 and the sheave 2. The measurement was carried out at an ambient temperature of 25 캜. The results are shown in Tables 1 and 2.

(2) Measurement method at a large sliding speed when emergency stop is performed

Fig. 3 is a conceptual diagram of an apparatus for measuring a coefficient of friction at a large sliding velocity in an emergency stop. The elevator rope 1 obtained in the examples and the comparative example was wound 180 degrees with respect to the driving sheave 5 and one end thereof was connected to the weight 4a and the other end was connected to the weight 4b ). Here, the weight 4a is raised by rotating the driving sheave 5 in the clockwise direction, and the driving sheave 5 is suddenly stopped at the time when the rope speed becomes 4 m / s and the elevator rope 1) was slipped. The weight (4a) a minimum deceleration tension of α, lettuce (4a) side of the time (T ₃₎ and autumn (4b) side tension (T ₄₎ the measurement by the load cell provided in the connecting portion of the rope and the weight And their values were substituted into the following formula ₂ to obtain the minimum friction coefficient μ ₂ during the slip. The measurement was carried out at an ambient temperature of 25 캜. Tables 1 and 2 show the results of the first (first) test and the results of the test when the same side of the resin coating layer was repeatedly slipped 10 times.

Where K ₂ is the same as that used in the measurement method in the minute slip speed reverse, and g is gravity ^{(= 9.80665m / s 2),} θ is a contact angle of the rope (= 180 degrees).

[Table 1]

[Table 2]

In the table, the friction stabilizer 1 is a polyethylene wax having a melting point of 115 캜, the friction stabilizer 2 is a polypropylene wax having a melting point of 150 캜, the friction stabilizer 3 is an ethylene / bisstearic acid amide having a melting point of 144 캜, The friction stabilizer 4 is a stearic acid amide having a melting point of 100 캜. The friction stabilizer 5 is a hardened castor oil having a melting point of 85 캜. The friction stabilizer 6 is a paraffin wax having a melting point of 55 캜. -Olefin wax, the friction stabilizer 8 is calcium stearate having a melting point of 155 占 폚, the inorganic filler 1 is titanium oxide, the inorganic filler 2 is glass fiber (fiber length is 1 mm), and the inorganic filler 3 is talc . ?, Those having a friction coefficient of less than 0.15 were evaluated as?, Those having a friction coefficient of less than 0.15 and less than 0.2 were evaluated as?, And those having a friction coefficient of 0.2 or more and less than 0.25 were evaluated as? However, in Examples and Comparative Examples, no coefficient of friction exceeding 0.6 was shown.

As can be seen from the results of Tables 1 and 2, using the elevator rope obtained in the examples and the comparative example, the friction coefficient in the small slip speed range (1 x 10 ^-5 mm / s) As compared to the friction coefficient of the steel sheet. Further, by repeating the same surface of the resin coating layer to slip under the sliding condition at the time of emergency stop, the coefficient of friction of the resin covering layer tended to be lower than that at the initial stage.

The elevator rope obtained in the Example exhibited a friction coefficient of 0.2 or more in both the slip speed range and the emergency stop after the first test. Particularly, Examples 7 to 9, in which a friction stabilizer, an isocyanate compound as a crosslinking agent, and an inorganic filler were used in combination, exhibited a small variation in friction coefficient. In particular, Example 8 in which glass fiber as a fibrous inorganic filler was added and talc It was found that the variation of the coefficient of friction was particularly small in Example 9 to which is added. In Examples 1 to 4 and 7 to 11 using an olefin-based compound as the friction stabilizer, it was found that the fluctuation of the friction coefficient at the time of stop keeping was particularly small.

On the other hand, all of the elevator ropes obtained in the comparative example have a problem that the coefficient of friction during normal operation becomes too low or the variation of the friction coefficient becomes large. In Comparative Examples 2 to 4 in which the friction stabilizer having a low melting point was used, the friction coefficient at the time of normal operation and at the time of stop keeping decreased with the decrease of the melting point. In Comparative Example 5 using the friction stabilizer having a too high melting point, the resin coating layer at the friction interface was remarkably damaged at the time of the friction test at the time of emergency stop and the friction coefficient was lowered. This is presumably because the melting point of the friction stabilizer is too high and the lubricating action of the friction stabilizer does not sufficiently function due to the frictional heat generated at the sliding interface. In Comparative Examples 6 to 12 in which at least one of the isocyanate compound and the inorganic filler was added without adding the friction stabilizer, when the sliding was performed under the sliding condition at the time of emergency stop, the coefficient of friction decreased every time the number of tests was repeated.

1 rope 2 sheave for elevator
3 Measuring device 4, 4a, 4b Addition
5 drive sheave

Claims (5)

A rope body, and a rope body, which are made of a thermoplastic polyurethane elastomer, a friction stabilizer having a melting point of 100 ° C or more and 150 ° C or less, and two isocyanate groups (isocyanate groups) Or more of a resin coating layer comprising a molded product of a resin coating layer-forming composition obtained by mixing an isocyanate compound. The method according to claim 1,
Wherein the friction stabilizer is an olefin compound. The method according to claim 1,
Wherein the inorganic filler is further mixed in the resin coating layer-forming composition. The method of claim 3,
Wherein the inorganic filler is fibrous or plate-like. The method according to claim 1,
Wherein the friction stabilizer is contained in an amount of not less than 0.5 wt% and not more than 5 wt% with respect to the resin coating layer forming composition.

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