JP2006063150A - Molded article of polyurethane resin and method for producing molded article of polyurethane resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded article of polyurethane resin having a proper rigidity, excellent in damping effect. <P>SOLUTION: The invention relates to the molded article of polyurethane resin comprising a polyurethane resin obtained by reacting a polyol and an isocyanate, and fibers, wherein the polyol comprises a straight chain polyol A with ≥1,000 of molecular weight and a polyfunctional polyol B with ≥550 of hydroxy value, and an isocyanate C which is a polymeric MDI is used as the isocyanate. And the molded article of polyurethane resin is used for a crosstie or a gasket. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyurethane resin molded article having excellent vibration damping properties. In particular, the present invention relates to a polyurethane resin molded body that can be used for a pillow installed between a sleeper, a rail and a sleeper, or between a sleeper and a portion that supports the sleeper.

  For railroad tracks, packings installed between sleepers and between rails and sleepers are used. This packing reduces vibrations during train running by adjusting the height between the sleeper and the rail and adjusting the height between the rail and the iron girder, etc. while absorbing the vibration by the packing.

Various materials, such as rubber | gum, are used for said packing according to use conditions. Further, Patent Document 1 discloses a conventional technique using a polyurethane resin molded body as the material.
JP 2000-281745 A

  In what is described in Patent Document 1, it is difficult to achieve both vibration reduction and high strength. That is, in order to reduce the vibration, it is necessary to increase tan δ (loss tangent). However, if this is increased too much, the material becomes soft and the strength decreases.

  Apart from this, there is a problem of disposal of materials such as waste materials that have been used for a long time and losses that occur during manufacturing. If these materials can be reused, environmental problems will be solved.

  Therefore, an object of the present invention is to provide a molded article of a polyurethane resin having an excellent vibration damping effect.

The invention according to claim 1 for achieving the above object is a polyurethane resin molded article having a polyurethane resin obtained by reacting a polyol and an isocyanate and a fiber, and the molecular weight of the polyol is 1000 or more. A polyurethane resin molded article characterized in that a straight-chain polyol A and a polyfunctional polyol B having a hydroxyl value of 550 or more are used, and isocyanate C, which is polymeric MDI, is used as the isocyanate. is there.
Here, the fibers used in the present invention may be inorganic fibers such as glass fibers, carbon fibers, metal fibers and ceramic fibers, synthetic fibers such as aromatic polyamide fibers, organic fibers such as natural fibers, etc. It is not limited. Moreover, the thing with high tensile strength is desirable.
The molecular weight of polyol A means a number average molecular weight in the case of a mixture in which molecules having a plurality of molecular structures are mixed.

  According to the first aspect of the present invention, the polyurethane resin molecule has a branched structure by the polyfunctional polyol B having a hydroxyl value of 550 or more, and the linear rigidity of the polyol A having a molecular weight of 1000 or more provides an appropriate rigidity. Therefore, it is possible to achieve both rigidity and damping performance.

The invention according to claim 2 is the polyurethane resin according to claim 1, wherein the amount of polyol A added is 50% to 90% by weight with respect to the total amount of polyol A and polyol B It is a molded body.

  According to invention of Claim 2, since the addition amount of polyol A is 50 weight%-90 weight% with respect to the total amount of polyol A and polyol B, the molecule | numerator of a polyurethane resin is made into a moderate branch structure. It can be.

  Glass fiber can be used as the fiber (claim 3).

  Moreover, it can also be used as a sleeper using the polyurethane resin molded article (claim 4), and as a packing installed between a rail and a sleeper or between a sleeper and a part supporting the sleeper It can also be used (Claim 5).

  The invention according to claim 6 includes a step of crushing a resin molded body having fibers, the crushed resin crushed material, a linear polyol A having a molecular weight of 1000 or more, and a hydroxyl value of 550 or more. It is a method for producing a polyurethane resin molded article, comprising a step of filling a mold with functional polyol B and isocyanate C, which is a polymeric MDI, and curing the mold in the mold.

  According to the invention described in claim 6, the resin molded body having fibers can be crushed, and a polyurethane resin molded body can be produced using the crushed material. It leads to reuse of resources and reduction of waste.

  The molded article of the polyurethane resin of the present invention is excellent in vibration damping performance and can be used for sleepers and packings. Also, resources can be reused.

  Hereinafter, specific examples of the present invention will be described. The polyurethane resin molded body of this embodiment includes a polyurethane resin and glass fibers. The polyurethane resin is obtained by reacting a polyol and an isocyanate.

As the polyol used for the polyurethane resin, polyol A and polyol B are used. Polyol A has a linear structure with a molecular weight of 1000 or more. Polyol B is a polyfunctional group having a functional group (hydroxyl group) of 3 or more and a hydroxyl value of 550 or more.
Thus, since the polyol A having a linear structure and the polyol B having a polyfunctional group are used in combination, the structure of the polyurethane resin after the reaction is formed with a linear part and a branched part. And moderate rigidity and a damping function can be provided.

Polyol A has a linear structure, and this linear structure has flexibility. Examples of the polyol having a linear structure having flexibility include polyglycol, specifically, polypropylene glycol (PPG), polytetramethylene glycol (PTMG), and the like. The polyol A has a functional group (hydroxyl group) at both ends of the linear structure.
Polyol A may have a molecular weight of 1000 or more. However, if the molecular weight is too large, the viscosity increases and the workability is lowered in the production process.

Polyol B is a polyfunctional group having 3 or more hydroxyl groups. Specifically, glycerin, trimethylolpropane (TMP), pentaerythritol and the like can be used, and these can be used alone or in combination of two or more. Can be used. In addition, the hydroxyl value of polyol B when two or more kinds of polyols are used is a value measured in a mixed state.

  A polyol obtained by reacting a functional group with ethylene oxide (hereinafter referred to as EO) or propylene oxide (hereinafter referred to as PO) can be used as the polyol B. In such a case, the cost can be reduced, but the hydroxyl value becomes small. Therefore, it is necessary to adjust the hydroxyl value to a range of 550 or more.

  The amount of polyol A added is desirably 50% by weight to 90% by weight with respect to the total amount of polyol A and polyol B. When the addition amount of polyol A is less than 50% by weight based on the total amount of polyol A and polyol B, the branched portion of the polyurethane resin is too much, and the addition amount of polyol A is polyol A and polyol B. When the total amount exceeds 90% by weight, the branched portion of the polyurethane resin is reduced.

  Polymeric MDI is used as the isocyanate C used for polymerization of the polyurethane resin. Polymeric MDI contains polyphenylene polymethylene polyisocyanate, which is said to be a polynuclear body having three or more benzene rings in one molecule. Polymeric MDI is a mixture of polyphenylene polymethylene polyisocyanate and methylene diphenyl isocyanate (hereinafter referred to as MDI). MDI has two benzene rings in one molecule and is called a binuclear body.

  The proportion of polyphenylene polymethylene polyisocyanate in the polymeric MDI is not particularly limited, but is preferably 28 to 36% by weight.

The molded body of this embodiment contains glass fibers.
The glass fiber may be a long fiber or a short fiber. Moreover, the thickness of the glass fiber used can use the thing of suitable thickness according to a use.

And when using the glass fiber of a short fiber, it is possible to reuse the glass fiber once used. In this case, molding can be easily performed by adding a pulverized resin to which glass fiber is added to a polyurethane resin, and adding a glass fiber and resin that are integrated.
Since any resin to which the glass fiber used after pulverization is added can be used, it is possible to reuse waste that has been used over a long period of time or lost during production. . In this case, the resin material to be reused is preferably a polyurethane resin.

  Further, the degree of pulverization of the resin to be reused is not limited, and may be pulverized so that the average particle diameter is 1 mm or more, and the average particle diameter is less than 1 mm. You may grind | pulverize so that it may become. In addition, when an average particle diameter is 1 mm or more, it is desirable to make it an average particle diameter become 5 mm or less.

  The polyurethane resin can be foamed. The specific gravity can be reduced by foaming. The expansion ratio can be adjusted according to the application.

  Although the molding method of the polyurethane resin molded body of the present invention is not particularly limited, it can be performed by the following method.

The first method is a method of individually molding using a predetermined mold.
As a specific example, a predetermined amount of polyol A, polyol B and isocyanate C and, if necessary, a blowing agent or a catalyst are added and mixed with a mixer or the like to prepare a resin liquid. And this resin liquid and glass fiber are put into a shaping | molding die, Then, it foams and hardens | cures and shape | molds.

  And when using the resin to which the glass fiber which became waste materials etc. was added, since the grind | pulverized resin can be put into a shaping | molding die in the case of shaping | molding, it can shape | mold easily. The blending ratio of the resin liquid and the pulverized resin can be changed depending on the particle size of the pulverized resin particles.

  Furthermore, in the case of molding using a mold, it can be molded in a compressed state when the resin liquid is cured. In such a case, the shape and specific gravity of the molded polyurethane resin molded body are stabilized.

The second method is a continuous molding method.
A predetermined amount of a polyol A, a polyol B and an isocyanate C and, if necessary, a foaming agent and a catalyst are added and mixed with a mixer or the like to prepare a resin solution. And the said urethane resin liquid is sprayed on the bundle of glass fibers, and a urethane resin liquid is soaked between glass fibers with a squeezing plate. Further, the glass fiber soaked with the urethane resin liquid is passed through a molding passage, and foamed and cured to be molded.

The polyurethane resin molded body molded as described above can be used for members such as sleepers. Specifically, it can be used for a pillow provided between a sleeper, a sleeper and a rail, or a lower part of the sleeper.
The packing is a member used for adjusting a gap or reducing vibration by being installed between a rail and a sleeper. And although packing can also be installed when laying a rail, it can be installed after laying a rail. By inserting packing between the rail and the sleeper, it is possible to fill a gap between the sleeper and the rail, which can be caused by wear or deformation of the sleeper by using the rail or loosening of the fastening portion.

When the polyurethane resin molded body is provided at the lower part of the sleeper tree, it can be provided between the ballast roadway or the concrete roadbed and the sleeper tree.
In the case of a bridge or the like, a polyurethane resin molded body can be provided between the iron beam and the sleeper. Furthermore, when fixing using a hook bolt as shown in FIG. 1, a polyurethane resin molded body can be provided between the hook bolt and the iron beam.

The polyurethane resin molded body of Example 1 was molded by the following method.
735 parts of polyol A (Sumiphen 3600, manufactured by Sumika Bayer Urethane Co., Ltd.), 265 parts of polyol B (SBU polyol 0555, manufactured by Sumika Bayer Urethane Co., Ltd.), 82 of isocyanate C (polymeric MDI SBU isocyanate 44V20, manufactured by Sumika Bayer Urethane Co., Ltd.) Part, 6 parts of foaming agent (SRX295 manufactured by Toray Silicone Co., Ltd.), 6 parts of water as a foaming agent, and 6 parts of organic tin catalyst (SCAT31A manufactured by Sansha Co., Ltd.) were blended. And what was mixed was uniformly disperse | distributed with the mixer, and the urethane resin liquid was adjusted.

  The main component of the polyol A of Example 1 is PPG or PTMG, and the average molecular weight is 1500. The main component of polyol B is TMP, and the hydroxyl value is 600.

The amount of polyol A added to the total amount of polyol A and polyol B in the urethane resin liquid of Example 1 is 73.5% by weight based on the total amount of polyol A and polyol B.
The proportion of polyphenylene polymethylene polyisocyanate in the polymeric MDI of Example 1 is 31.5% by weight.

Next, glass fiber and a fiber-reinforced urethane resin crushed material are put into a mold.
As the glass fiber, a chop (cut product) having an outer diameter of 0.01 mm and a length of 40 mm was used. The fiber-reinforced urethane resin crushed material has an average particle size of 4 mm.
Put 438 parts of glass fiber, 1149 parts of crushed fiber reinforced urethane resin, and 1449 parts of the urethane resin liquid, and react with polyol A, polyol B, and isocyanate C in a sealed state and cure while foaming. A polyurethane resin molded product of Example 1 was obtained.
The density of the polyurethane resin molded body of Example 1 is 0.88 g / cm ³ .

The polyurethane resin molded body of Example 2 was molded by the following method.
735 parts of polyol A (Sumiphen 3600 manufactured by Sumika Bayer Urethane Co., Ltd.), 265 parts of polyol B (SBU polyol 0555 manufactured by Sumika Bayer Urethane Co., Ltd.), 73 of isocyanate C (polymeric MDI SBU isocyanate 44V20 manufactured by Sumika Bayer Urethane Co., Ltd.) Part, 0.2 part of organotin catalyst (SCAT31A manufactured by Sansha Co., Ltd.) was blended. And what was mixed was uniformly disperse | distributed with the mixer, and the urethane resin liquid was adjusted.
The amount of polyol A added to the total amount of polyol A and polyol B in the urethane resin liquid of Example 2 is 73.5% by weight based on the total amount of polyol A and polyol B.

Next, glass fiber and a fiber-reinforced urethane resin crushed material are put into a mold.
As the glass fiber, a chop (cut product) having an outer diameter of 0.01 mm and a length of 40 mm was used. The fiber-reinforced urethane resin crushed material has an average particle size of 0.1 mm.
175 parts of glass fiber, 1940 parts of crushed fiber reinforced urethane resin, and 1794 parts of the urethane resin liquid are added. And the polyol A, polyol B, and isocyanate C were made to react in the sealed state, and it was made to harden | cure while making it foam, and the polyurethane resin molding of Example 2 was obtained.
Moreover, the density of the polyurethane resin molded body of Example 2 is 1.13 g / cm ³ , and the shear strength is 20 MPa.

A packing used between the rail and the sleeper, or between the sleeper and the part supporting the sleeper, as it is, or by cutting or polishing the polyurethane resin molded body of Examples 1 and 2 into a predetermined shape. This was manufactured and tested for vibration damping.
In addition, the polyurethane resin molded body of Example 1 has a large amount of glass fiber and high rigidity as compared with the polyurethane resin molded body of Example 2, and is foamed with a foaming agent. small.

Three methods were used to confirm the vibration suppression effect.
The first method uses a structure in which a simulated iron girder is manufactured, a sleeper is installed on the iron girder, and the sleeper is fixed with hook bolts, and the polyurethane resin molded body of the present invention is formed between the sleeper and the iron girder. This is a method for checking the vibration control effect when the weight is dropped at a position corresponding to the rail installation, between the hook bolt and the iron beam, between the hook bolt and the sleeper.
The second method uses a structure in which a sleeper is installed on a concrete roadbed, and the polyurethane resin molded body of the present invention is placed between the sleeper and the roadbed, between the bolt and the roadbed, and between the bolt and the sleeper. This is a method for confirming the vibration control effect when the weight is dropped at a position corresponding to the rail installation.
The third method uses a structure in which a simulated ballast roadbed is manufactured and a sleeper tree is installed on the simulated ballast roadbed, the polyurethane resin molded body of the invention is placed between the sleeper and the roadbed, and a weight is placed at a position corresponding to rail installation. This is a method for confirming the vibration control effect when dropped.

  A simulated iron girder 10 used in the first method is shown in FIG. 1, and two simulated iron girders 10 made of H-shaped steel are fixed to a base portion 11. A sleeper 50 is placed on top of the simulated iron girder 10. The sleeper 50 is provided with a through hole 50a, and the hook bolt 12 is inserted into the through hole 50a. The upper part of the hook bolt 12 is fixed by a nut 51, and the hook part 13 is hooked on the simulated iron girder 10 at the lower part. The sleeper 50 is fixed by the hook bolt 12.

  A weight 16 is prepared on the sleeper 50 to be dropped at a position corresponding to the rail installation position, and a flat jig 17 having a projection 17a is placed on the sleeper 50 at a position where the weight 16 is dropped. The weight 16 is 10 kg, and is freely dropped from 15 cm above the jig 17. Then, vibration is generated by freely dropping the weight 16.

First, in order to measure the reference vibration, the weight 16 is dropped on the protrusion 17a without using the polyurethane resin molded body of the present invention, and the vibration at the accelerometer 15 is measured. The state in which the polyurethane resin molded body is not used is a state as shown in FIG. 2. When the weight 16 is freely dropped in this state, vibration is generated in the jig 17, and this vibration is simulated through the sleeper 50. It is transmitted to the iron girder 10. And the vibration transmitted by the accelerometer 15 provided in the simulated iron girder 10 is measured.
The measurement by the accelerometer 15 was FFT-analyzed in the range of 0 to 2000 Hz, and evaluated by an average value of 10 times.

Next, the packing 53 formed of the polyurethane resin molded body of Example 1 is placed between the sleeper 50 and the simulated iron girder 10 so as to be in the state shown in FIG. The vibration is measured by 15.
Further, the packing 54 formed of the polyurethane resin molded body of Example 1 is disposed between the hook portion 13 of the hook bolt 12 and the simulated iron girder 10 so as to be in the state shown in FIG. The vibration is measured by the accelerometer 15.
Further, the packing 55 formed of the polyurethane resin molded body of Example 1 is arranged between the nut 51 for fixing the hook bolt 12 and the sleeper 50, and is in a state as shown in FIG. Vibration is measured by the accelerometer 15.

As a result, when the packing 53 was arranged between the sleeper tree 50 and the simulated iron girder 10, the 5 dB vibration was reduced as compared with the case where the packing 53 was not arranged. In addition, when the packing 54 is disposed between the hook portion 13 of the hook bolt 12 and the simulated iron girder 10, 3 dB vibration is reduced as compared with the case where the packing 54 is not disposed. Further, when the packing 55 is disposed between the nut 51 for fixing the hook bolt 12 and the sleeper 50, the 2 dB vibration is reduced as compared with the case where the packing 55 is not disposed.
As described above, when the packings 53, 54, and 55 were used, the vibration damping effect was confirmed in any case.

  The concrete roadbed 20 used in the second method is shown in FIG. 6 and is formed by placing concrete up to about the middle of the internal space 22 of the frame portion 21.

First, in order to measure the vibration as a reference, as shown in FIG. 7, the sleeper 50 is placed on the concrete roadbed 20, and in that state, concrete is placed on the side of the sleeper 50, and the concrete part 25 is Provide and fix the sleeper 50.
In addition to this, as shown in FIG. 8, the packing 56 formed of the polyurethane resin molded body of Example 2 is installed on the concrete roadbed 20, and the sleeper 50 is disposed on the packing 56, and then the sleeper 50 Concrete was placed on the sides of the steel plate to provide a concrete portion 25 and a pillow 50 fixed thereto.

  For these two types, using the same weight 16 and jig 17 as described above, the weight 16 to be dropped onto the sleeper 50 at a position corresponding to the rail installation position is dropped, and the accelerometer 15 provided on the sleeper 50 is provided. The vibration transmitted by is measured. The accelerometer 15 is provided on the sleeper tree 50.

  As a result, when the packing 56 was disposed between the sleeper tree 50 and the concrete roadbed 20, 2 dB vibration was reduced as compared with the case where the packing 56 was not disposed.

Moreover, the damping effect was confirmed also about what fixed the pillow 50 and the concrete roadbed 20 using the volt | bolt 23 using the concrete roadbed 20. FIG.
First, in order to measure the vibration as a reference, as shown in FIG. 9, the sleeper 50 and the concrete roadbed 20 were fixed with bolts 23.

  Further, as shown in FIG. 10, in which the packing 57 formed of the polyurethane resin molded body of Example 2 is disposed between the sleeper 50 and the concrete roadbed 20, the sleeper 50 is fixed by the bolts 23. Produced. As shown in FIGS. 11 and 13, the packing 58 formed of the polyurethane resin molded body of Example 2 is placed between the sleeper tree 50 and the nut 24 for fixing the bolt 23, and the sleeper tree 50 is secured by the bolt 23. I made a fixed one. As shown in FIGS. 12 and 14, a structure in which the sleeper 50 was fixed in a state where the packing 59 formed of the polyurethane resin molded body of Example 2 was disposed between the bolt 23 and the concrete roadbed 20 was manufactured.

  Using these four types of structures, using the same weight 16 and jig 17 as described above, the weight 16 is dropped on the sleeper 50 at a position corresponding to the rail installation position. The vibration transmitted by the existing accelerometer 15 was measured.

As a result, when the packing 57 was disposed between the sleeper tree 50 and the concrete roadbed 20, 3 dB vibration was reduced as compared with the case where the packing 57 was not disposed. Moreover, when the packing 58 was arrange | positioned between the sleeper 50 and the volt | bolt 23, 2 dB vibration decreased compared with the case where it does not arrange | position. Furthermore, in the case where the packing 59 is disposed between the bolt 23 and the concrete roadbed 20, 2 dB vibration is reduced as compared with the case where the packing 59 is not disposed.
As described above, when the packings 56, 57, 58, 59 were used, the vibration damping effect was confirmed in any case.

A simulated ballast roadbed 30 used in the third method is shown in FIG. The simulated ballast roadbed 30 is placed in the internal space 22 of the frame portion 21.
And in order to measure the vibration used as a reference | standard, as shown in FIG. 15, the sleeper 50 is arrange | positioned in the internal space 22, and the simulation ballast roadbed 30 is provided so that the downward direction and the side of the sleeper 50 may be covered.
Further, as shown in FIG. 16, the packing 60 formed of the polyurethane resin molded body of Example 3 was arranged between the sleeper tree 50 and the simulated ballast roadbed 30.

  Using these two types of structures, using the same weight 16 and jig 17 as described above, the weight 16 to be dropped onto the sleeper 50 at a position corresponding to the rail installation position is dropped and provided on the sleeper 50. The vibration transmitted by the existing accelerometer 15 is measured.

  As a result, when the packing 60 was disposed between the sleeper tree 50 and the simulated ballast roadbed 30, 3 dB vibration was reduced as compared with the case where the packing 60 was not disposed, and the vibration damping effect was confirmed.

Moreover, the polyurethane resin molding of this invention can also be continuously shape | molded with the following method.
The same urethane resin liquid as in Example 1 is prepared, the urethane resin liquid is sprayed on a bundle of glass fibers (glass roving having a fiber diameter of about 20 μm), and the urethane resin liquid is soaked between the glass fibers by a kneading plate. Make it. Further, the glass fiber infiltrated with the urethane resin liquid is passed through a molding passage, cured while being foamed, and continuously molded.
The amount of the glass fiber of this polyurethane resin molding is 1314 parts with respect to 1449 parts of the urethane resin liquid, the density of the polyurethane resin molding after molding is 0.8 g / cm ³ , and the tensile modulus is 5000 MPa.

  The molded body continuously molded in this way can be cut into a predetermined length and used as a packing used between a sleeper, a rail and a sleeper, or between a sleeper and a part supporting the sleeper. .

It is the front view which showed the structure of the mock iron girder for evaluating damping performance. FIG. 2 is an enlarged partial cross-sectional view of the vicinity of a hook bolt in FIG. 1. It is the partial cross section figure which showed the structure for evaluating the damping performance of packing with the mock iron girder. It is the partial cross section figure which showed the structure for evaluating the damping performance of packing with the mock iron girder. It is the partial cross section figure which showed the structure for evaluating the damping performance of packing with the mock iron girder. It is the front view which showed the structure of the concrete roadbed for evaluating damping performance. It is sectional drawing which showed the structure for evaluating damping performance in the state which does not use packing by a concrete roadbed. It is sectional drawing which showed the structure for evaluating damping performance in the state using packing by the concrete roadbed. It is sectional drawing which showed the structure for evaluating damping performance in the state which does not use packing by a concrete roadbed. It is sectional drawing which showed the structure for evaluating damping performance in the state using packing by the concrete roadbed. It is sectional drawing which showed the structure for evaluating damping performance in the state using packing by the concrete roadbed. It is sectional drawing which showed the structure for evaluating damping performance in the state using packing by the concrete roadbed. It is the partial cross section figure which expanded the bolt vicinity of FIG. It is the partial cross section figure which expanded the volt | bolt vicinity of FIG. It is sectional drawing which showed the structure for evaluating damping performance in the state which does not use packing by a simulated ballast roadbed. It is sectional drawing which showed the structure for evaluating damping performance in the state using packing by the simulated ballast roadbed.

Explanation of symbols

53, 54, 55, 56, 57, 58, 59, 60 Packing

Claims (6)

A polyurethane resin molded article having a polyurethane resin obtained by reacting a polyol and an isocyanate and fibers,
As the polyol, a linear polyol A having a molecular weight of 1000 or more and a polyfunctional polyol B having a hydroxyl value of 550 or more are used, and an isocyanate C which is a polymeric MDI is used as an isocyanate. A polyurethane resin molded product.   2. The polyurethane resin molded article according to claim 1, wherein the amount of polyol A added is 50 wt% to 90 wt% with respect to the total amount of polyol A and polyol B. 3.   The polyurethane resin molded article according to claim 1 or 2, wherein the fibers are glass fibers.   A sleeper using the polyurethane resin molded article according to any one of claims 1 to 3.   It is manufactured using the polyurethane resin molded body according to any one of claims 1 to 3, and is installed between a rail and a sleeper or between a sleeper and a part supporting the sleeper. .   A step of crushing a resin molded body having fibers, the crushed resin crushed product, a polyol A having a linear structure having a molecular weight of 1000 or more, a polyfunctional polyol B having a hydroxyl value of 550 or more, and a polymeric MDI A process for producing a polyurethane resin molded article, comprising a step of filling a mold with isocyanate C, which is

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