KR102266175B1 - Elastic PAD for railroad - Google Patents

Abstract

An object of the present invention is to provide a novel elastic pad for a railroad, which is a non-foam material and has excellent anti-vibration performance and excellent durability by controlling physical properties of hardness, tensile strength, and elongation. Another object of the present invention is to provide an elastic pad for a railroad having high dimensional stability and minimizing molding defects, and a method for manufacturing the same. The elastic pad is manufactured by mixing a first reaction liquid and a second reaction liquid and molding a mixture thereof.

Description

Elastic PAD for railroad

The present invention relates to an elastic pad for railroad use. More specifically, the present invention relates to an elastic pad for a railway suitable for expressing vibration-absorbing performance of a non-ballasted railway track such as a bridge such as an iron bridge during the running of a railway vehicle, and as a non-foam material, physical properties of hardness, tensile strength and elongation It relates to a new elastic pad for railways with excellent vibration-proof performance and excellent durability by adjusting the

For railroad rails, railroad pads are used as vibration-proof materials to reduce tremendous vibration or noise generated while high-load and high-speed railroad vehicles run.

Such an elastic pad for railway includes a pad inserted between the rail and the sleeper, a pad for a sleeper installed under the sleeper, a vibration-proof material for a track slab installed under the slab of the slab track, and the like.

Conventionally, SBR rubber, etc. has been used, but the rail pad made of soft non-foaming rubber with a low spring constant has a problem in that it does not have sufficient durability. In addition, in the case of rubber, the load distribution is not good, so there is a problem that the durability is further deteriorated, such as cracks occur in the part where stress is concentrated during long-term use, for example, the fastening part.

To solve this problem, foamed polyurethane is sometimes used, but in the case of foamed polyurethane, vibration absorption and mechanical properties are not balanced, and the vibration-proof performance cannot be sufficiently maintained due to the destruction of the foamed cell according to long-term use. . In addition, in the case of foamed polyurethane foam, since it has low tensile strength and elongation, the foam cell is destroyed in the compression set test and may not satisfy the railroad standard of less than 5%.

Japanese Laid-Open Patent Publication No. 2000-281745 (October 10, 2000)

In order to solve the above problems, in the present invention, as a result of many studies, various physical properties to be equipped as the anti-vibration pad for railway exist, but excellent dust-proof and cushioning performance are expressed, and the characteristics of hardness, tensile strength and elongation are very important The present inventors have been deeply aware that the present invention has been completed.

That is, the present invention is to provide a new anti-vibration pad for railways, which is a non-foaming material and has excellent anti-vibration performance and excellent durability by controlling the physical properties of hardness, tensile strength, and elongation.

Another object of the present invention is to provide a railway anti-vibration pad having high dimensional stability and minimizing molding defects, and a method for manufacturing the same.

Specifically, the present invention has a hardness of 58A to 68A, a tensile strength of 150kgf/cm2 or more, and an elongation of 500% or more before aging, and aging at 100°C for 96 hours and standing at room temperature for 24 hours. It is to provide a new polyurethane elastic pad in which the increase rate of tensile strength is 40% or more and the increase rate of elongation is 15% or more compared to the tensile strength before the test.

One aspect of the present invention for achieving the above object is a non-foamed polyurethane elastic pad, wherein the elastic pad is

(A) a first reaction solution comprising an isocyanate-terminated polyurethane prepolymer prepared by polymerizing methylene diphenyl diisocyanate (MDI) and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol; And,

(B) a second reaction solution comprising a catalyst and a diol containing 90 to 98 moles of polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol and 2 to 10 moles of a C2 to C6 diol having two functional groups; As manufactured by mixing and molding,

It relates to a non-foamed polyurethane elastic pad prepared by mixing the molar ratio of the first reaction solution and the second reaction solution in a ratio of 1 to 1.2: 1.

Another aspect of the present invention is a method for manufacturing a non-foaming polyurethane elastic pad,

a) preparing a first reaction solution comprising an isocyanate-terminated polyurethane prepolymer prepared by polymerizing methylene diphenyl diisocyanate (MDI) and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol;

b) To prepare a second reaction solution comprising a catalyst and a diol containing 90 to 98 moles of polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol and 2 to 10 moles of a C2 to C6 diol having two functional groups step,

c) after stirring and mixing the first reaction solution and the second reaction solution, putting it into a molding mold and thermoforming to prepare a mold;

d) manufacturing an elastic pad by processing the thermoformed mold;

It relates to a method for manufacturing an elastic pad for non-foaming railway comprising a.

The elastic pad of the present invention can provide a polyurethane non-foaming elastic pad that can satisfy all physical properties such as high mechanical strength, durability and hardness.

In addition, according to the present invention, it is possible to provide an elastic pad for a non-ballasted track having excellent physical properties, particularly in the non-balling track.

In addition, the hardness of the present invention is 58A to 68A, the tensile strength is 150kgf/cm2 or more, and the elongation is 500% or more. Compared to the physical properties before aging, the physical properties after the aging test are 40% or more, the elongation is It is to provide a new polyurethane elastic pad that exhibits increased physical properties by 15% or more.

More specifically, after aging the charcoal pad of the present invention for 96 hours in a 100 ℃ thermostat, it was left in a closed space for 24 hours and cooled to room temperature, and then the measured hardness was 58A to 68A, and the tensile strength was 200 kgf / ㎠ or more, More preferably, it is 200 to 400 kgf/cm 2 , and it is possible to provide an elastic pad having an elongation of 650% or more, and more preferably 650 to 680%.

Hereinafter, the present invention will be described in more detail. However, the following specific examples or examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the invention.

Also, the singular forms used in the specification and appended claims may also be intended to include the plural forms unless the context specifically dictates otherwise.

In addition, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated.

One aspect of the present invention is a non-foaming polyurethane elastic pad, wherein the elastic pad is

(A) a first reaction solution comprising an isocyanate-terminated polyurethane prepolymer prepared by polymerizing methylene diphenyl diisocyanate (MDI) and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol; And,

(B) a second reaction solution comprising a catalyst and a diol containing 90 to 98 moles of polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol and 2 to 10 moles of a C2 to C6 diol having two functional groups; As manufactured by mixing and molding,

It is a non-foaming polyurethane elastic pad prepared by mixing the molar ratio of the first reaction solution and the second reaction solution in a ratio of 1 to 1.2: 1. In the range that satisfies the molar ratio, it is possible to obtain a polymer having NCO at the end of the polyurethane, and in this case, it is better to achieve the desired physical properties in the present invention.

In one aspect, the non-foamed polyurethane elastic pad may have a hardness of 58 A to 68 A, a tensile strength of 150 kgf/cm 2 or more, and an elongation of 500% or more.

In one aspect, the non-foamed polyurethane elastic pad has a hardness of 58A to 68A, and a tensile strength of 250 kgf/cm 2 after aging for 96 hours in a 100 ° C constant temperature bath, leaving it to stand in a closed space for 48 hours, cooling it to room temperature, and then Above, the elongation may be 650% or more.

Another aspect of the present invention is a method for manufacturing a non-foaming polyurethane elastic pad,

a) preparing a first reaction solution comprising an isocyanate-terminated polyurethane prepolymer prepared by polymerizing methylene diphenyl diisocyanate (MDI) and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol;

b) To prepare a second reaction solution comprising a catalyst and a diol containing 90 to 98 moles of polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol and 2 to 10 moles of a C2 to C6 diol having two functional groups step,

c) after stirring and mixing the first reaction solution and the second reaction solution, putting it into a molding mold and thermoforming to prepare a mold;

d) manufacturing an elastic pad by processing the thermoformed mold;

It is a method of manufacturing an elastic pad for non-foaming railway comprising a.

Hereinafter, each configuration will be described in more detail.

In one aspect of the present invention, the first reaction solution includes an isocyanate-terminated prepolymer having a terminal isocyanate. Polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol, which has two functional groups to form a soft segment, mixed with the prepolymer and the second reaction solution, and a C2 to C6 diol forming a hard segment are reacted with the hard segment to form a hard segment By arranging units having soft segments according to the above ratio, the hardness (measurement method KS M6518:2018) targeted by the present invention is 58A to 68A, tensile strength (measurement method KS M6518:2018) is 150kgf/cm2 or more, and elongation ( The measurement method KS M6518:2018) can provide a new polyurethane elastic pad having properties of 500% or more. In addition, it is possible to provide a new polyurethane elastic pad in which the physical properties measured after the aging test exhibit properties such as an increase in tensile strength of 40% or more and an increase in elongation of 15% or more compared to before the aging test.

More specifically, the increase rate of tensile strength and elongation after the aging test means (physical properties measured after aging - physical properties measured before aging)/physical properties measured before aging × 100.

By simultaneously satisfying the above range, it is possible to express physical properties suitable for use as an elastic pad for railway rails, and it is possible to provide an elastic pad for railroad rails with little change in physical properties even for long-term use.

<First reaction solution>

The first reaction solution is a solution containing an NCO group-terminated prepolymer, and the NCO group-terminated prepolymer is reacted with MDI and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol to prepare a terminal isocyanate prepolymer. Within the above molecular weight range, the physical properties aimed at the present invention can be satisfied.

The first reaction solution is obtained by reacting an isocyanate with a polyol.

The isocyanate used in the present invention is preferably MDI, and is not particularly limited. For example, 4,4'-MDI, 2,4'-MDI, and 2,2'-MDI may be used, and 4 It is best to use ,4'-MDI (4,4'-Methylenebis(phenyl isocyanate)) alone.

Examples of the polyalkylene glycol include polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), and polyoxytetramethylene glycol (PTMG), but there is no limitation as long as the molecular weight is satisfied, preferably PTMG It is more preferred to use alone to achieve the object of the present invention. The polyalkylene glycol is preferable because it is suitable for expressing more desired physical properties in the range of a weight average molecular weight of 500 to 3000 g/mol.

The isocyanate-terminated polyurethane prepolymer can be prepared by mixing an MDI-based isocyanate and a polyol, and heating the mixture for a urethanation reaction.

The isocyanate-terminated polyurethane prepolymer does not contain a low molecular weight diol component in order to control the elongation, tensile strength and hardness of the present invention, and when a diol having a different chemical structure such as polycarbonate diol or polyester diol is used. It is not good because sufficient weather resistance and aging characteristics aimed at the invention are not satisfied.

It is better to control the NCO content of the NCO group-terminated prepolymer to 8 to 16 mass% and use it to control the foaming effect by water when reacting with the next second reaction solution. If the amount of bubbles is not good, it is not good because there is a disadvantage that the reaction does not proceed sufficiently.

<Second reaction solution>

The second reaction solution is a reaction solution containing diol reactants and a urethane reaction catalyst for providing a polyurethane with soft and hard segments by reacting with the first reaction solution to provide a vibration-proof pad having the same characteristics as an elastomer.

As the diol compound providing the soft segment, the same polyalkylene glycol belonging to the category used in the first reaction solution having a weight average molecular weight of 1000 to 3,000 g/mol is used. By using the same type, the physical properties aimed at the present invention can be sufficiently satisfied, and there is a characteristic that the physical properties are improved in the aging test.

That is, the polyalkylene glycol can be exemplified by polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), polyoxytetramethylene glycol (PTMG), etc., but there is no limitation as long as the molecular weight is satisfied, preferably The use of PTMG alone is more preferred in achieving the object of the present invention.

Next, a description will be given of a diol providing a hard segment.

An example of the diol providing the hard segment in the present invention is C1-C6 alkylene glycol. By using the alkylene glycol, weather resistance or aging resistance is more excellent, and degradation due to long-term use may be minimized. In addition, the hardness, tensile strength and elongation characteristics of the present invention can be imparted as it is.

Examples of the alkylene glycol providing the hard segment include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. , 1,5-pentanediol, 1,6-hexanediol, and the like. In the case of oxyalkylene such as diethylene glycol and dipropylene glycol, the elongation rate decreases in the aging test, which is not good.

In the second reaction solution, when the molar ratio of the diol compound giving the soft segment and the hard segment is 90 to 98:10 to 2, the present invention can achieve physical properties.

In one aspect of the present invention, the reaction ratio of the first reaction solution and the second reaction solution is the elastic pad of the present invention by reacting the molar ratio of the isocyanate-terminated prepolymer and the diol compound of the second reaction solution in a molar ratio of 1 to 1.2:1. It is better in the sense that the present invention achieves physical properties to manufacture.

In addition, if necessary, the second reaction solution may further include any additives commonly used in the field, for example, a catalyst, a foam stabilizer, a colorant (pigment dye), an antioxidant, and an ultraviolet absorber. have.

In the method of manufacturing an elastic pad using the first reaction solution and the second reaction solution, the above-mentioned compositions are mixed, mechanically stirred, and then injected into a molding mold and cured, so that polyurethane non-foaming constituting the railroad pad is made. Characterized in manufacturing an elastic pad.

More specifically, for example,

a) preparing a first reaction solution comprising an isocyanate-terminated polyurethane prepolymer prepared by polymerizing methylene diphenyl diisocyanate (MDI) and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol;

b) To prepare a second reaction solution comprising a catalyst and a diol containing 90 to 98 moles of polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol and 2 to 10 moles of a C2 to C6 diol having two functional groups step,

c) after stirring and mixing the first reaction solution and the second reaction solution, putting it into a molding mold and thermoforming to prepare a mold;

d) manufacturing an elastic pad by processing the thermoformed mold;

includes

The thermoforming in step c) is not limited thereto, but may be cured by heat treatment at a temperature of 60 to 150 ℃, more preferably after the first heat treatment at a temperature of 60 to 110 ℃ for 1 to 10 hours, 120 It may be cured by performing a secondary heat treatment at a temperature of 150 ° C. for 1 to 10 hours.

In the manufacturing method of the present invention, it is best if the content of water in the composition is not present, but for example, if it is managed to 0.1 mass % or less, pores due to water are prevented from being formed, and there is no defect in the manufactured elastic pad. good.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following Examples and Comparative Examples are merely examples for explaining the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Example 1]

<Preparation of first reaction solution: Preparation of prepolymer>

MDI 46.6 wt%, PTMG-2000 (polytetramethylene glycol with a weight average molecular weight of 2000 g/mol) 20 wt%, PTMG-1000 (polytetramethylene glycol with a weight average molecular weight of 1000 g/mol) 33.39 wt%, Diethylene glycol as an inhibitor An isocyanate-terminated prepolymer was prepared by heating polymerization using 0.01 wt% of biscro formate. The NCO content of the prepared prepolymer was 12% by weight, and it was confirmed that it had a terminal isocyanate group.

<Second reaction solution preparation: diol and catalyst composition>

A second reaction solution was prepared by mixing 0.035 parts by weight of a tin-based catalyst (Fomrez UL-94) with respect to 100 parts by weight of a diol mixture containing 93.7 mol of PTMG-1000 and 6.3 mol of 1,4-butanediol.

<Mold molding>

The molar ratio of the isocyanate of the isocyanate group-terminated prepolymer of the first reaction solution to the molar ratio of the hydroxyl group of the diol in the second solution is mixed in a ratio of 1.05:1, and sufficiently mixed through a stirrer at 45° C. for 30 seconds to prepare a composition After that, the composition was put into the molding mold and cured at 80°C. The curing reaction was performed at 80° C. for 5 hours and at 120° C. for 5 hours to prepare an elastic pad.

After separating the elastic body from the manufactured mold, a specimen was prepared and physical properties were measured. As a result, hardness of 66A, tensile strength of 179.6 kgf/cm 2 , and elongation of 580% were obtained.

In addition, the physical properties measured after aging the specimen in a thermostat at 100° C. for 96 hours, leaving it to stand for 24 hours and cooling it to room temperature, have an amazing physical property retention effect of hardness of 61A, tensile strength of 263.3 kgf/cm2, and elongation of 680%. confirmed that.

[Example 2]

Example 1 was carried out in the same manner as in Example 1, except that the molar ratio of PTMG-1000 to 1,4-butanediol was 95:5 as the second reaction solution.

As a result, a hardness of 62A, a tensile strength of 232.1 kgf/cm 2 , and an elongation of 510% were obtained.

In addition, as a result of performing the same aging test as in Example 1, it was confirmed that it had a surprising effect of maintaining properties of 65A, tensile strength of 301.2 kgf/cm 2 , and elongation of 650%.

[Comparative Example 1]

Example 1 was carried out in the same manner as in Example 1, except that the molar ratio of PTMG-1000 to 1,4-butanediol was 85:15 as the second reaction solution.

As a result, a hardness of 58A, a tensile strength of 301.3 kgf/cm 2 , and an elongation of 230% were obtained.

In addition, as a result of the same aging test as in Example 1, the physical properties of the present invention could not be satisfied with 75A, tensile strength of 290.4 kgf/cm 2 , and elongation of 190%.

As described above, the present invention has been described with specific details and limited examples and drawings, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention is not limited to the above embodiments. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (4)

A non-foamed polyurethane elastic pad, the elastic pad comprising:
(A) a first reaction solution comprising an isocyanate-terminated polyurethane prepolymer prepared by polymerizing methylene diphenyl diisocyanate (MDI) and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol; And,
(B) a second reaction solution comprising a catalyst and a diol containing 90 to 98 moles of polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol, 2 to 10 moles of a C2 to C6 diol having two functional groups; As manufactured by mixing and molding,
It is prepared by mixing the molar ratio of the first reaction liquid and the second reaction liquid in a ratio of 1 to 1.2: 1 ;
The non-foamed polyurethane elastic pad has a hardness of 58 A to 68 A, a tensile strength of 150 kgf/cm 2 or more, and an elongation of 500% or more, a non-foamed polyurethane elastic pad. delete The method of claim 1,
The non-foamed polyurethane elastic pad had a hardness of 58A ~ 68A, a tensile strength of 250 kgf/cm2 or more, and an elongation rate of 58A ~ 68A, after aging in a 100 ℃ thermostat for 96 hours, leaving it in a closed space for 48 hours and cooling to room temperature Non-foaming polyurethane elastic pad of 650% or more. A method for manufacturing a non-foamed polyurethane elastic pad, comprising:
a) preparing a first reaction solution comprising an isocyanate-terminated polyurethane prepolymer prepared by polymerizing methylene diphenyl diisocyanate (MDI) and polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol;
b) preparing a second reaction solution comprising a catalyst and a diol containing 90 to 98 moles of polyalkylene glycol having a weight average molecular weight of 500 to 3000 g/mol and 2 to 10 moles of a C2 to C6 diol having two functional groups step,
c) after stirring and mixing the first reaction solution and the second reaction solution, putting it into a molding mold and thermoforming to prepare a mold;
d) manufacturing an elastic pad by processing the thermoformed mold;
A method of manufacturing an elastic pad for non-foaming railway comprising a.