JPS6197317A - Elastic coating agent for directly coupled sleeper - Google Patents

Abstract

PURPOSE:The title coating agent excellent in vibration isolation, attenuation, absorption and damping effects, comprising a foaming stock solution containing three specified polyols, an organic polyisocyanate, a chain extender, a blowing agent and a urethane formation catalyst. CONSTITUTION:An elastic coating agent comprising a low-expansion ratio urethane bond-containing elastomer of a bulk density of 0.4-0.75g/cm<3>, prepared from a foaming stock solution comprising a polyether-polyol (a) of an average functionality of 2.5-4.5 and a number-average MW of 2,000-3,500, a vinyl monomer-grafted polyol (b) of an average functionality of 2.5-4.0 and a degree of grafting of 4-20wt%, a liquid, hydroxyl-terminated polybutadiene-polyol (c) of an average functionality of 2.0-3.0 and a number-average MW of 2,000-7,000, an organic polyisocyanate (d), a chain extender (e), a blowing agent (f) and a urethane formation catalyst (g), said foaming stock solution having an NCO index of 90-110 and containing said chain extender at a concentration of 0.3X10<-3>-1.5X10<-3>mol/g, based on the total of the five component, a, b, c, d and e.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an elastic covering for a direct-tie sleeper made of a low-foam urethane elastomer having urethane bonds of the following types. More specifically, it is a railway that can exhibit excellent vibration isolation, vibration damping, photographic absorption, and/or vibration damping effects even under high loads and under conditions where deformation is restrained on railways where long trains run at high speeds. This invention relates to an elastic covering material for direct-coupled track sleepers.

In recent years, as railways have become faster, concrete sleepers or slab tracks have been replaced with conventional pallast-covered tracks in order to save labor in track maintenance, improve train running stability, and shorten construction time. Direct-coupled track, which is constructed directly on a solid roadbed surface, is often used. Among these methods, from the perspective of reducing vibration and noise, in the method of burying and fixing sleepers on the concrete road surface using filled concrete, etc. (direct-attached sleepers), the vibration isolating material used in the middle is filled concrete. As this vibration isolating material is
To use an elastic material that firmly adheres to concrete sleepers even when such free deformation is restrained, and exhibits an excellent effect of reducing vibration transmission and suppressing noise generation without increasing the spring constant. is necessary.

In particular, in the case of railway tracks where long trains run at high speed, the physical properties required of the elastic sheathing material for elastic sleepers become even more severe. Permanent set: 15% or less Spring constant: 0.2-2 ton/crIL/100
cm" Tensile strength: 5 kgf/cm" or more Tensile elongation = 1001% or more Water resistance (Tensile strength change rate): Within ±209b (Tensile elongation change rate): Within ±20% Alkali resistance (Tensile strength change rate) : within ±20% (rate of change in tensile elongation): within ±20 yen Fatigue resistance: set as 1.0 u or less in fatigue resistance, and materials that simultaneously satisfy all of these physical property requirements must be used. is required.

Moreover, one of the important requirements is that the elastic covering material firmly adheres to concrete sleepers and filled concrete, and does not peel off even under repeated compression caused by intermittent train running.

The present inventors have previously developed an elastic covering material that fully satisfies these requirements and has an average number of functional groups of 2. ．． 5 to 3.5 and a number average molecular weight of about 4,500 to about 8,500, an organic polyisocyanate, a chain extender, a urethanization catalyst, and a blowing agent, and the chain extender is equal to the unit weight of the urethane elastomer. 0.2 x 10-3 to 1 per
．． A bulk density of 0.3 to 0.9 f produced from a urethane elastomer foam stock solution containing a concentration of 0 x 10-' mol/f
discovered that a low-foaming urethane disstomer of ``/crIL'' was suitable (Japanese Patent Application Laid-Open No. 13075-1985).
(See Publication No. 4).

The low-foam urethane elastomer proposed earlier satisfies the above specifications and is actually applied to straight sections of high-speed railway tracks. It goes without saying that even in such an elastic material such as a low-foaming urethane elastomer, it is preferable from an economic point of view to lower the bulk density to reduce the amount of raw materials used.

However, there is a drawback that lowering the bulk density lowers the Gene constant. However, especially in curved sections of high-speed railway tracks, large centrifugal forces are applied, and the elastic covering material is greatly compressed. As a result, a void is created between the elastic covering material and the reflective concrete, and there is a risk that moisture and dust may get mixed in there. cannot be used. For example, on January 1, the bulk density of the low foaming urethane elastomer is set to 0.7 f7cm' or less, and at the same time, the spring constant is set to 1. Otr/cm/100c
If an attempt is made to maintain it at around m', there is a problem in that the compression set increases.

Therefore, the present inventors conducted intensive research in search of a foamed urethane elastomer that does not substantially increase compression resistance even when the bulk density is lowered, and as a result, the present invention was completed.

Therefore, according to the present invention, (a) a polyether polyol having an average functional group number of Z5 to 4.5 and a number average molecular weight of 2000 to 8500; (b) a polyether polyol having an average functional group number of Z5 to 4.0 and grafting. (e) a liquid polyptadiene polyol having a hydroxyl end with an average functional group number of 20 to aO and a number average molecular t of 2000 to 7000; (d) an organic polyol; isocyanate, (e) chain extender, (f) blowing agent, and (b))
It consists essentially of a urethanization catalyst and has an NCO index of 90 to 110.
and the chain lengthening agent is within the range of (a) and (b) above.
, (c), (d) and (e) in a concentration of 0.3 x 10-3 to 1.5 x 10-'' mol/f based on the total amount of the five components. It is made of a foamed urethane elastomer with urethane bonds and a bulk density of 0.4 to 0.75 f/an''!
An elastic glazed material for a direct-coupled elastic sleeper is provided.

The polyether polyol (a) used as one of the polyol components in the preparation of the urethane elastomer of the present invention has an average number of functional groups of 25 to 4.5 and a number average molecular weight of 2,000 to 8,500. What is the average number of functional groups in the polyether polyol used? , 5, the permanent compression strain of the foamed urethane elastomer obtained therefrom becomes large; conversely, when the average functional number exceeds 4.5, the obtained elastomer tends to become hard and when subjected to vibration compression. This increases the risk of the elastomer being damaged, both of which are undesirable. Therefore, the preferred average number of functional groups of the polyether polyol (a) is 25 to
A value of 4.5 is desirable, and a range of 28 to 4.0 is desirable for beads.

Furthermore, if the number average molecular weight of the polyether polyol (a) is less than 2,000, it is difficult to obtain a foamed urethane elastomer with high vibrational energy absorption characteristics;
If it exceeds 00, the elastic properties of the resulting urethane elastomer will decrease and plastic deformation will likely occur, and in particular, there will be a tendency for permanent compressive strain to increase. Therefore, the polyether polyol used in the present invention generally has 2
It is desirable to have a number average molecular weight in the range of 000 to 8,500, preferably 3,000 to 6,500.

The polyether polyol (a) includes any one commonly used in the preparation of urethane elastomers, and specifically includes aliphatic polyhydric alcohols having 2 to 6 carbon atoms such as glycerin and trimethylolpropane. Alternatively, examples include polyether polyols obtained by addition-polymerizing a lower alkylene oxide having 2 to 4 carbon atoms per carbon atom, such as ethylene oxide, propylene oxide, etc., to an active hydrogen compound having an active hydrogen atom such as ethylenediamine or diaminodiphenylmethane. . Typical examples of such polyether polyols (a) include copolymer adducts of glycerin/propylene oxide/ethylene oxide (average functionality = 3.0.a average molecule 42) 3000): propylene glycol/propylene oxide / copolymer adduct of ethyl oxide (average functional group number = zO1 number average molecule [4800); copolymer adduct of glycerin/pentaerythritol/propylene oxide/ethylene oxide (average functional group number 3.7, average molecular weight 5700), etc. is included.

The present invention uses the above polyether polyol (
In combination with a), a vinyl monomer graft polyol 0)) with an average functional group number of 25 to 4.0 and a grafting rate of 4 to 20% by weight and an average functional group number of zO to 3.0 and a number average One major feature lies in the use of a liquid polyptadiene polyol (c) having a hydroxy end group with a molecular weight of 2,000 to 7,000.

[Vinyl monomer graft polyol] (referred to as graft polyol) (b) used in the present invention is a modified polyol produced by in-situ radical polymerization of vinyl heptanomer in the presence of a normal polyol, It is itself known as a polyol component for producing high modulus urethane foam (for example,
Japan Machikei No. 447628, U.S. Patent No. 3033841
British Patent No. 874130, German Patent No. 1077
No. 430, No. 1105179, No. 1081917, and No. 1111394, see the literature in Publication No. 1989-93729). In the present invention, among such graft polyols, a Tokuden graft polyol having an average number of functional groups of 2.5 to 4.0 and a grafting rate of 4 to 20% by weight is particularly used.

If the average number of functional groups of the graft polyol used is less than 2.5, the permanent compression set of the resulting low-foaming urethane elastomer will be large, which is not appropriate. It shows a tendency to become hard. The preferable range of the average number of functional groups of the graft polyol is 25 to 4.0, with the most suitable range being 2.5 to 3.0. In addition, if the grafting ratio of the graft polyol is less than 4 times or t, the compression set will be poor, and if it exceeds 20 times M%, the viscosity of the liquid will increase and the moldability will deteriorate significantly. . Therefore, the grafting "P" of the graft polyol is 4 to 20% by weight, especially 5 to 15% by weight.
A range of % by weight is preferred.

The term "grafting ratio" as used herein refers to the ratio of the vinyl monomer graft polymerized to the polyether among the vinyl monomers added, based on the weight of the polyether.

The polyol forming the base of such graft polyol (b) has a number average molecular weight of 2500 to 8500,
Those having a hydroxyl value of preferably 4,000 to 7,000 and a hydroxyl value of 20 to 67, preferably 24 to 50 are advantageously used, for example, glycerin added and polymerized with ethylene oxide and/or propylene oxide. Examples include polyalkylene ether glycol having an average molecular weight of 4,800.

On the other hand, examples of vinyl monomers grafted onto these polyols include styrene, vinyltoluene,
-butene, 2-hexene, 1,4-hexadiene, 1,
Examples include olefins such as 3-butadiene and 3-pentene; vinyl halides such as vinyl chloride and vinylidene chloride; nyletinic unsaturated carboxylic acids such as acrylic acid and methacrylic acid or derivatives thereof (alkyl esters, etc.); vinyl acetate, etc. , these can be used alone or in combination of two or more.

The grafting of the vinyl monomer to the polyol is accomplished by radical polymerization of the vinyl monomer in the presence of the polyol according to a method known per se. Examples of usable radical polymerization catalysts include peroxide-based, azo-based or redox-based polymerization initiators, and metal compound catalysts. The kraft polyol thus obtained generally has a polyol of 2,500 to 8
It can have a number average molecular weight of 500, preferably 4000 to 7000.

Therefore, the graft polyol particularly preferably used in the present invention has a number average molecular number of about 5100, for example.
The product obtained by graft polymerizing polypropylene ether glycol having a functional group number of about 3 with acrylonitrile and styrene as polymerization initiators and azobisisobutyronitrile in an autoclave at 120°C for 8 hours can be obtained. .゛On the other hand, RP-type polybutadiene boriol J (c) is a liquid butadiene homopolymer or cobolinu having a reactive hydroxy group at the end, especially an allyl-type primary hydroxy group, which is known per se. So) (if you line up,
For example, 1,3-butadiene alone or 1,3-butadiene and an ethylenically unsaturated monomer having 2 to 12 carbon atoms at 7544 of the total monomer For example, it can be produced by radical addition polymerization of styrene, acrylonitrile, vinyl acetate, etc. in the presence of hydrogen peroxide as a polymerization catalyst.

In the present invention, among such liquid polyptadiene polyols, particularly those having an average number of functional groups of 2. ．． 0 to 3.0 and a number average molecular weight of 2000 to 7000 is used. The average number of functional groups of the liquid polyptadiene polyol used is 20.
If it is smaller, it will be difficult to obtain a product with a high spring constant, the permanent compression set will be large, water hammer will occur, and the compatibility with the polyether polyol (synthesis and vinyl monomer graft polymer polyol (b)) used in combination will become poor. Next, there is a tendency for the moldability to deteriorate significantly.On the other hand, if it exceeds 3.0, the obtained urethane elastomer lacks elasticity,
It becomes extremely brittle, there is no improvement in water resistance and alkali resistance, and there is a tendency for fatigue resistance to become extremely poor.

Therefore, the average number of functional groups of the liquid polyptadiene polyol (e) is in the range of zO to 3.0, particularly 2.1 to 2.
A range of 8 is optimal.

In addition, e average molecule j of the liquid polyptadiene polyol
If the tensile strength is lower than 2000, the rate of change in strength and elongation in the water resistance and alkali resistance of the obtained elastomer will be significantly improved (1-< much), and the fatigue resistance and permanent compressive set (4-3) will be significantly lower. However, the closed cell ratio also decreases. 7000 on the contrary
If it is too low, the viscosity of the liquid will be too high, resulting in poor miscibility with seriiso/anate (d), which will not only reduce the tensile strength of the resulting elastomer but also make it impossible to obtain a good spring density. The closed cell ratio also decreases. The liquid polyptadiene polyol thus suitably has a number average molecular weight in the range of 2,000 to 7,000, preferably 2,400 to 5,000.

Furthermore, the liquid polyptadiene polyol (c) has a general KO of 35 to 1. It is desirable to have a doxy content in the range of 17 t/f and an iodine number in the range of 400 to 500.

Therefore, as a liquid polyptadiene polyol that can be particularly suitably used in the present invention, for example, a hydroxy-terminated butadiene homopolymer having an average functional group number of 2.1lEk to z4 and a number average molecular number of about 2800 (for example, ARCO
PolybdR-45HT manufactured by Che book m1ca1),
The average number of functional groups is 2.2 to 2.4 and the number average molecular weight is approximately 360.
0 hydroxy-terminated butadiene/styrene phosphorimer (
Example, ttf ARCOChe-mica 1g poly bd C8-15), average number of functional groups 2.
A hydroxy-terminated butadiene/acrylonitrile copolymer (e.g. A
RCO Chemi ca1 M polybdCN-
15), etc.

The mixing ratio of the liquid polyptadiene polyol (c) that can be particularly suitably used in the present invention is in the range of 1 to 70% by weight, preferably 2 to 40% by weight, and one level lower. If it exceeds 70% by weight, there will be no synergistic effect on alkali resistance when used in combination with the vinyl monomer graft polyol (b).

Vinyl monomer grafted polyol (b) according to the invention
and liquid polyptadiene polyol (e) t- By using in combination, the tensile strength can be lowered by lowering the bulk density even under load and under conditions where deformation is restrained, such as in direct-coupled elastic sleepers. It is possible to obtain a urethane elastomer that has a high spring constant, suppresses permanent compressive strain, and has a small rate of change in strength and elongation in water resistance and alkali resistance, which is not seen in conventional elastic bodies. It turned out that it was possible to obtain a unique effect that had never been seen before.

On the other hand, the organic polyisocyanate (d) reacted with the polyol components (a), (b) and (c) described above.
) can be any of those commonly used in the production of urethane distomers, such as 4,4'-diphenylmethane diisocyanate (M, D, L), naphthylene diisocyanate, tolylene diisocyanate,
Examples include hexamethylene diisocyanate. These organic polyiso7anates can be used alone or in a mixture of two or more. Further, the polyisocyanate (d) can also be used as a precursor, ie, a prepolymer or semi-prepolymer, which is precondensed with the above-mentioned polyhydric alcohol.

In any case, the amount of the organic polyisocyanate (d) to be used is determined based on the total amount of active hydrogen-containing components (polyol component, chain extender, It is possible to vary K within a range of stoichiometrically equal to (e.g.) to ±10 degrees thereof, that is, it is possible to adjust K so that the NGO index falls within a range of 90 to 110.

The chain extender (e) used for forming the urethane distomer in the present invention reacts with the organic polyisocyanate (d) to form mainly hydrogen bonds through urethane bonds, urea bonds, etc. This is an important component that forms the node segment and controls the elastic properties of the obtained urethane elastomer, and in the present invention, a substantially difunctional active hydrogen compound with a relatively low molecular weight is used. is advantageously used as the chain lengthening agent. Such a chain lengthening agent (e)
Examples include ethylene glycol, propylene gelylcol, propanediol, butanediol, hydroquinone, hydroxyethylquinone ether, etc.
~10 diols; amines such as methylenebis-(O-dichloroaniline), quadrol, ethylenediamine, and triethanolamine are included, and each of these can be used alone or in combination of two or more types. .

According to the research of the present inventors, when the chain extender (e) is used in combination with the polyol components (a), (b) and (c), the bifunctional chain extender ( The blending amount of e) is 0.3 x 10-" mol/f to 1.5 x 10-" based on the total amount of the five components (a), (b), (e), (d) and (e). It was found that it is appropriate to use the concentration in the range of 'mol/f.If the concentration is lower than this, the chain lengthening effect is not sufficient, so the strength of the obtained foamed urethane elastomer tends to be generally low. On the other hand, at a concentration of 1.5XlO'mol/Liyoshi, the number of hydrogen bonds increases more than necessary, so the strength of the resulting urethane disstomer improves, but it tends to become an extremely hard elastomer, so it is difficult to compress. It is less desirable for applications such as those in the present invention, which are subject to permanent set and cyclic compressive stress.However, the preferred concentration range for the chain extender (en) is 0.5 x 10-''/f~ ffi 1.2
X 10- ”Moni/f Te@ru.

In addition, as the urethanization catalyst, those commonly used in the b-urethanization reaction, such as tertiary amine compounds, organometallic compounds, etc., can be used. N
-Methylmorpholine, N,N-dimethylethanolamine; tin octylate, dibutyltin laurate, and the like. The amount of catalyst used is not critical and may vary over a wide range depending on the desired reaction rate, or it may be necessary to adjust the amount as appropriate depending on the amount of foaming of the urethane distomer and atmospheric conditions (temperature, humidity, etc.). be. but,
Adjusting the amount of catalyst used is a common practice in the industry, and selection is easy.

Furthermore, in the present invention, a foamed urethane elastomer is molded, and the blowing agent (f) used in the production of this foam is a conventional blowing agent, such as water or a halogenated hydrocarbon (e.g. nitrichlorofluorocarbon). Methane, methylene chloride), etc. The degree of foaming of the urethane elastomer desired in the present invention is not strictly limited, but unlike ordinary urethane foam, it is important that the degree of foaming is relatively low, and it is generally expressed in terms of bulk density of 0. .4 to 0.75 f/att", more preferably 0.55 to 0.7 f/cWL", and the amount of the foaming agent (0 used and/or foaming amount The bulk density of the resulting urethane elastomer can be adjusted to fall within the above range.

In addition to the above-mentioned components, the urethane elastomer foaming stock solution according to the present invention includes, as required, as usual,
Foam stabilizers (e.g. silicone surfactants, etc.), pigments (
For example, carbon black, etc.) can also be added.

Each component of the urethane elastomer foaming stock solution described above is thoroughly mixed immediately before use according to a conventional method, and then
An elastic sleeper having an elastic covering material can be manufactured by injecting it into a formwork attached to a concrete sleeper using the method described in Japanese Patent No. 130754.

The present invention will now be further illustrated by examples and comparative columns.

The physical properties in Examples and Comparative Examples were measured by the methods described below.

(1) Bulk density: According to JIS Z 8807 rMeasurement method from volume.

(2) Compression set: JIS K 6301rl
O.

Conforms to "compression set test".

(Temperature 70℃, 30 inch compression, 22 hours heat treatment) (3)
Spring constant: Conforms to JIS K 63ssrs, Static Spring Constant Test.

(Using a sample of 10crnX 10CrrLX Z5cm, pressurize at 425kl?
(4) Tensile strength and tensile elongation: JIS K 630
1.Measurement is performed using a Simenbel No. 1 test piece according to ``3. Tensile test method''.

(5) Water resistance: Using the same No. 1 Dampel test piece used in the tensile strength test, immerse it in distilled water or ion-exchanged water for 96 hours, wipe it gently, and immediately conduct the tensile strength test to determine the rate of change from the value before aging. demand.

(6) Alkali resistance: Same as (5) above except that the immersion liquid was a 1% (caustic potash/caustic soda 1:1) aqueous solution and the immersion temperature was 50°C.

(7) Fatigue resistance: 5RIS (Japan Rubber Association standard specification)
According to 3502. (Test conditions are precompression amount 5 - swing width 4wz)
(Vibration frequency: 5H2%, repetition rate: 1X10 times, test piece size: 5QX50X25 times) (8) Closed cell property: According to ASTM2856-70A method.

Liquids A and B having the composition shown below were charged into a stirrer and mixed at a rotational speed of 6000 rpm, then immediately poured into a mold of an appropriate size, allowed to cool at room temperature for 2 hours, and then demolded to obtain a foamed urethane elastomer. Ta. The physical properties of this urethane elastomer were measured by the method described above. The results are shown below.

Implementation row 1 A liquid composition 2 Overlapping part polyether polyol (1) 35 (copolymer adduct of glycerin/propylene oxide/ethylene oxide; average number of functional groups 3 - average molecular weight polyether polyol (n), 40
(Copolymer adduct of glycerin/pentaerythritol/propylene oxide/s-tylene oxide; average number of functional groups: 3.7; average molecule: 5700) Graft polyol 15 (copolymer adduct of glycerin/propylene oxide/ethylene oxide) Polymer polyol obtained by graft polymerizing acrylonitrile and styrene to (molecular weight 5100) in the presence of azobisisobutyronitrile (polymerization initiator): Average functional group number 3; Grafting rate 10%; Average number molecular weight 6000) Hydroxy Terminal liquid polybutadiene polyol 15 (average functional group number 2.5 - number average molecular weight ethylene glycol 7 water
0.53
Triethylenediamine 0,7 polyisocyanate/polyol prepolymer 100 (4,
Isocyanate-terminated precondensate of 4'-diphenylmethane diisocyanate and glycerin/propylene oxide/ethylene oxide copolymer adduct of average molecular f6500 (average functional group number 3; free NGO content = 16 polyh) Physical properties Bulk density : 0.63P/crIL" Spring constant: 1.50 tf/cm/100cr
n" Compression permanent set: 20 cm Tensile strength: 13.0 kg/cm" Tensile elongation = 145% Water resistance tensile strength change *knee 0.9% Tensile elongation change rate: -0.3% Alkali resistance tensile strength change Tensile elongation change rate knee 0.3% Tensile elongation change rate knee 0.2cm Fatigue resistance: Sagging 0.26m Closed cell property: Closed cell ratio 100% Example 2 Composition of liquid A: Part by weight Polyether polyol (n)
52 (copolymer adduct of glycerin/pentaerythritol/propylene oxide/ethylene oxide: average functional group number 3.7; average molecular weight 5700) Graft polyol 15 (copolymer adduct of glycerin/propylene oxide/ethylene oxide (average molecular weight - 115100) with acrylonitrile and styrene in the presence of azobisisobutyronitrile (polymerization initiator); average functional group number 3; grafting rate 10%; average molecular 4116000) hydroxy terminal Liquid polybutadiene homobooriol 3.0 (average number of functional groups 2.3; number average molecular weight 4700; hydroxy content t0.5 milliequivalent/f; iodine number 450) Ethylene glycol 5.7 Water
0.
48 Triethylenediamine 0.7
Polyisocyanate/polyol prepolymer 100 (4
, 4'-diphenylmethane diisocyanate and a copolymer adduct of glycerin/propylene oxide/ethylene oxide with an average molecular weight of 6500; isocyanate-terminated precursor condensate; free NGO content = 16% by weight) Physical properties Bulk density: 0.69 P/cm" Spring constant Number 2 〇, 98 t f /cm/ 100♂ Compression set: 3.8 inches Tensile strength: 14.91zQ/an" Tensile elongation: 210 inches Water resistance Tensile strength change rate knee 3.7 inches, Tensile elongation Change rate knee 4.3 cm Alkali resistance Tensile strength change rate knee 2.2% Tensile elongation change rate knee 4.1 cm Fatigue resistance: Hetashi 1ftO, 16ai + Closed cell property: Closed cell ratio 99.9% Comparison Example I Part A Composition 2 Parts by weight Polyether polyol 100 (copolymer adduct of glycerin/propylene oxide/ethylene oxide; average functional group number 3; average molecule *6500) Ethylene glycol 9.7 Water
0
．． 58 Triethylenediamine 0.
7B liquid introduction: NCOI nde
x Polyincyanate/polyol prepolymer 100 (4,
Isocyanate-terminated condensate of 4'-diphenylmethane diisocyanate and the above-mentioned polyethyl polyol; free NGO content = 16% by weight) Physical properties Bulk density: 0.63 t/cIIL Spring constant: 0.98tb-100F Compression set: 34 inches Tensile strength: 22.3 kg/cm" Tensile elongation: 78 inches Water resistance tensile strength change rate: -18.8 inches Tensile elongation change rate knee 25.0 inches Alkali resistance tensile strength change rate: -35,2chi 1 Tensile elongation change rate knee 35.0chi Fatigue resistance: Settling amount 1.5 am Closed cell property: Closed cell ratio 88.4chi Comparative example 2 Polyether polyol (1) 35(
Copolymer adduct of glycerin/propylene oxide/ethylene oxide; average functional group number 3; average molecular weight 3000) Polyether polyol ([1) 35
(copolymer adduct of glycerin/pentaerythritol/propylene oxide/ethylene oxide; average functional group number 3.7; average molecular weight graft polyol 3° (copolymer adduct of glycerin/propylene oxide/ethylene oxide (average molecular weight 5100) with acrylonitrile) Polymer polyol obtained by graft polymerizing and styrene in the presence of azobisisobutyronitrile (polymerization initiator); average functional group number 3; krafting rate 15 inches; average molecular weight 6500) Ethylene glycol 6.1 Water
0.51 Triethylenediamine 0.7 Prepolymer of polyisocyanate/polyol 100 (4,4
Inocyanate-terminated precursor condensate of '-diphenylmethane diisocyanate and glycerin/propylene oxide/ethylene oxide copolymer adduct (average molecular weight 6500; free NGO content = 161i%) Physical properties Bulk density: 0.63f/cIrL3 Spring constant: 0. 97kgf/cIIL40
0 m" Compression set = 17% Tensile strength: 11.5'Q/cm" Tensile elongation: 120 cm Water resistant tensile strength change rate Knee 19.0 cm Tensile elongation change rate: -211 cm Alkali resistance tensile strength change Rate knee 17.8% Tensile elongation change rate knee 18.5% Fatigue resistance: Hetashi amount 1.35 Closed cell property: Closed cell rate 93.4% Comparative example 3 A liquid composition 2 Part by weight polyether Polyol (U) 90 (copolymer adduct of glycerin/pentaerythritol/propylene oxide/ethylene oxide; average number of functional groups 3,7; average number of molecules [5700) Hydroxy-terminated butadiene/acrylonitrile copolymer polyol 10 (average functionality Radix 2..8; Number average molecular t5000; Hydroxy-containing band 0.9; Iodine number 400) Ethylene glycol 5.7 Water
0.
48 Triethylenediamine 0.7
B liquid composition: NCOI n
dex polyisocyanate/polyol prepolymer 100 (4,4
Isocyanate-terminated precondensate of '-diphenylmethane diisocyanate and glycerin/propylene oxide/ethylene oxide copolymer adduct with an average molecular weight of 6500 (average functional group number 3; free NGO content = 16 t%) Physical properties Dense : 0.63P/cm3 Spring constant:
0.65 tf/crIL/100cm
"Compression set: 1.3 cm Tensile strength: 16.3 to 9/cm" Tensile elongation: 160% Water resistance Tensile strength change rate knee 18.4% Tensile elongation change rate: -17.2 cm Alkali resistance Tensile strength change *knee 15.2% Tensile elongation change rate knee 17.4% Fatigue resistance: Settling amount 1.151u1 Closed cell property: Closed cell ratio 926cm Reference example 1: Manufacture of direct-coupled elastic sleepers 400w x 2000m x 200U A concrete block 1 having dimensions 1.5 as shown in FIG.
Set in a mold 2 with 3 degassing holes of wφ, and set the coating thickness (W, W" in Figure 2) and height (h in Figure 2) to 2, respectively.
5m and 150IIIj. Next, using the apparatus shown in FIG. 3, liquids A and B having the compositions shown in Example 1 were mixed in a stirrer 5 at a rotational speed of 600 rpm and injected from the lower part 4 of the mold. After leaving it at room temperature for 1 hour, it was demolded to obtain a direct-coupled elastic sleeper.

This prototype sleeper was compressed using an Amsler compression tester, and the strain of the elastic covering material was determined to fit? I measured my feet. The results are shown in the graph of FIG.

Using liquids A and B described in Comparative Examples 1.2 and 3, a colleague fabricated a prototype direct-coupled elastic sleeper, and measured the amount of strain and its change. The results are shown in the graph of FIG.

In the figure, curve (1)-0- is the load-strain amount curve of the elastic covering material of Example 1, (2)-Δ-1(3)-low and (
4) -X- is the load-strain amount curve of the coating materials of Comparative Examples 2.3 and 1, respectively.

From the results shown in FIG. 4, the coating material of the present invention (coating material of Example 1) has a lower load than the coating material of Comparative Examples 1.2 and 3.
It is clear that the strain curve is steeped in linearity and is much more durable.

Reference Example 2 As shown in Figure 5, concrete block 11 (100
&11X10011JIX30011JI) by the same method as described in Reference Example 1
A sensor 15 is attached to the center of the bottom surface of the covering material 12, and concrete 14 is poured and hardened so as to surround it. Next, concrete block 11
Apply an impact with a hammer to approximately the center of the top surface, and the impact 1
The base of 3! ! 14 (Height: 200 ms, Width: 250 mm, Length: 400 mm, 9 to 39) is detected by the sensor 15, sent to the signal processor (manufactured by Sanwa Sokki) 17 via the amplifier 16, and sent to the recorder 18. Record the attenuation situation. The chart is shown in FIG. In FIG. 6, (1), (2), and (3) Fi are the results when the coating materials of Example 1 and Comparative Examples 3 and 1 were used, respectively. As is clear from this result, the coating material of the present invention (Example 1
) has small and short impact vibrations, and when compared to those of Comparative Examples 3 and 1, the vibration damping is less than 5 to 5, and the vibration damping effect is significantly superior.

[Brief explanation of drawings]

Figure 1 is a perspective view of a mold attached to a concrete block, Figure 2M is a sectional view taken along the line A-A in Figure 1, Figure 3 is a flow sheet for manufacturing elastic sleepers, Figure 4 is for company reference. Figure 5 is a schematic diagram of the experimental apparatus for measuring the vibration damping effect, and Figure 6 is a graph showing the measurement results of the vibration damping effect.

Claims (1)

[Scope of Claims] (a) A polyether polyol having an average number of functional groups of 2.5 to 4.5 and a number average molecular weight of 2,000 to 3,500, (b) A polyether polyol having an average number of functional groups of 2.5 to 4.0, and a vinyl monomer graft polyol with a grafting rate of 4 to 20% by weight; (c) a liquid polyptadiene polyol having a hydroxy end group with an average functional group number of 2.0 to 3.0 and a number average molecular weight of 2000 to 7000; Consists essentially of (d) organic polyisocyanate, (e) chain extender, (f) blowing agent, and (g) urethanization catalyst, and has an NCO index of 90 to 110.
and the chain extender is within the range of (a), (b),
Based on the total amount of the five components (c), (d) and (e), 0.3 x 10^-^3 to 1.5 x 10^-^3 mol/
An elastic coating for direct-attached sleepers, characterized in that it is made of a low foaming urethane elastomer having a urethane bond and having a bulk density of 0.4 to 0.75 g/cm^3, prepared from a urethane elastomer foam stock solution containing a concentration of Material.