JPH0140866B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for filling the gap between a track slab and a concrete roadbed in a slab track. As a gap filling composition for slab tracks used in Shinkansen tracks, etc., cement-asphalt mortar mixed with cement, asphalt emulsion, sand, etc. is used for ordinary slabs, and urethane or epoxy is used for turnouts and beveled slabs. A type of resin mortar is used. However, although cement asphalt mortar is inexpensive, it does not have the elasticity equivalent to bedded track and is brittle. Resin mortar can be easily adjusted to meet the performance requirements of various slab track filling layers, and has high strength and high elasticity. However, the price of resin mortar is more than 10 times higher than cement asphalt mortar, and its use is currently limited to turnouts and angle slabs that require higher performance than ordinary slabs. Therefore, the present invention aims to provide a low-cost slab track filling composition that has physical and chemical properties similar to those of the current urethane resin mortar whose main components are isocyanate and polyether polyol or (and/or) amine compounds. We aim to provide the following. The features of the present invention include extender pigment, multicyclic aromatic hydrocarbon resin (hereinafter referred to as aroma group process oil polymer), petroleum-based high boiling point hydrocarbon oil (hereinafter referred to as process oil), diisocyanate, terminal It consists of hydroxylated polybutadiene, polyether polyol, a small amount of organometallic catalyst, and a water absorbing agent, and the elastic modulus of the cured product can be freely changed depending on the type and amount of polyether polyol added. Typical extender pigments used in the present invention are calcium carbonate, talc, and silica powder, and if these extender pigments have the same particle size, water concentration, and volumetric pigment concentration in the cured product, they exhibit approximately similar physical properties. Obtain a cured product. The mixing ratio of the extender pigment is preferably within the range of 20 to 40% (weight %, same hereinafter).
This is because if the extender content is less than 20%, sufficient reinforcement and strengthening of the powder cannot be expected, and if it exceeds 40%, fluidity may decrease and workability may deteriorate. The aroma group process oil polymer and process oil used in the present invention have extremely good compatibility with diisocyanates and polybutadiene diols, and this compatibility is a key point that ultimately determines the quality of the cured product performance. That is, during or after the reaction between the diisocyanate and the terminally hydroxylated polybutadiene, components with poor compatibility separate and ooze out, making it impossible to obtain a homogeneous and stable cured product. Most commercially available aroma group process oil polymers have a molecular weight of 250 to 650, and the average molecular weight is
When the number is 350 or higher, many of them are solid at room temperature. In the present invention, it is preferable to use a composition that does not increase the viscosity as much as possible, such as a liquid type with an average molecular weight of 260. The process oil preferably has a viscosity-reducing effect based on its composition, and has a molecular weight of 150 to 200. The mixing ratio of the aroma group process oil polymer is preferably 30 to 50%. If the aroma group process oil polymer content is less than 30%, other substances must be added, which is undesirable in terms of cost, and if it exceeds 50%, fluidity may decrease and workability may deteriorate. Further, the mixing ratio of process oil is preferably 5 to 15%. This is because if the process oil is less than 5%, a sufficient reduction in viscosity cannot be expected, and if it exceeds 15%, it may shrink over time due to its high volatility. Commercially available process oils are generally classified into paraffin, naphthenic, and aromatic types, but the compatibility with the composition of the present invention is good regardless of the use of any process oil, and there is no significant difference in curing performance between the process oils. There is no need to limit the type. Therefore, for convenience of organization, an aromatic process oil was used in the examples of the present invention. The diisocyanate used in the present invention, the curing components polybutadiene diol and polyether polyol, have high reactivity, and since an organometallic catalyst is used, there is no need to limit the type of diisocyanate. Therefore, tolylene diisocyanate and crude diphenylmethane diisocyanate, which are inexpensive, are suitable. However, since tolylene diisocyanate has a rather low reactivity and a rather strong toxicity, it is preferable to use crude diphenylmethane diisocyanate. If the diisocyanate content is less than 3%, it will be difficult to secure a cured product with a certain strength, and if it exceeds 15%, a correspondingly large amount of terminal hydroxylated polybutadiene will be required, which will increase consumption and be undesirable in terms of cost. becomes. The terminal hydroxylated polybutadiene used in the present invention is a diol with an average molecular weight of 2800 and has an allyl-type primary hydroxyl group at the end of polybutadiene containing 80% 1,4-butadiene and 20% 1,2-butadiene. It has many unsaturated double bonds,
In addition, since the terminal hydroxyl group is primary, it exhibits good reactivity with diisocyanates. Similar polybutadiene containing 60 to 70% 1,2-butadiene is also commercially available. As described above, polybutadiene containing a large amount of 1,2-butadiene has a high viscosity, which may not necessarily be desirable depending on the purpose of use. In addition, since polybutadiene is non-polar within the molecule (there are no ether or ester bonds within the molecule)
Shows good compatibility with various resins. The polyether polyol used in the present invention is 3
Terminal hydroxyl polyether (average molecular weight 300 to
1000) or limited to terminal hydroxyl polyethers (average molecular weight 300 to 1000) obtained by copolymerizing propylene oxide and ethylene oxide. Polyhydric alcohols include glycerin, trimethylolpropane, diglycerin, pentaerythritol, seurose, and the like, which are commercially available products with trifunctional to octafunctional functions. The effect of polyether polyol on the performance of cured products is that the curing performance can be changed depending on the number of functional groups, molecular weight, and amount added of polyether polyol. For example, 1) the composition of the present invention containing 4% of the total amount of trifunctional polyether polyol with a molecular weight of 700; 2) the composition of the present invention containing 3% of the total amount of tetrafunctional polyether polyol with a molecular weight of 700; 3) the composition of the present invention containing 4% of the total amount of trifunctional polyether polyol with a molecular weight of 700; As a result of measuring the hardness of the cured products of 4 compositions of the present invention containing 4% of the total amount of ether polyol and 4) the present composition of the present invention containing 4% of the total amount of tetrafunctional polyether polyol with a molecular weight of 400, the hardness of the cured product of each composition was determined. became 1) 37, 2) 38, 3) 47, 4) 56.
That is, this result shows that the hardness of the cured product is proportional within a certain range to the amount of introduced functional groups that form a three-dimensional network structure. However, liquid diphenylmethane diisocyanate is used as the diisocyanate at this time, and consideration is given to suppressing the three-dimensional network structure caused by the diisocyanate. Furthermore, since the polyether polyol is used by adding a small amount to the composition of the present invention, and an organic metal catalyst is used, there is almost no difference in performance due to the difference between polyoxypropylene type and polyoxypropylene polyoxyethylene type. As an effective catalyst for promoting urethane reactions,
Generally, organic metals such as dibutyltin dilaurate and lead octylate are used, and are also effective for the polybutadiene composition of the present invention. The water absorbing agent used in the present invention is mainly used for the purpose of adsorbing water in extender pigments, and soluble anhydrite or synthetic zeolite is used. The mixing ratio of the water absorbing agent varies depending on the amount of extender pigment, but is preferably within the range of 5 to 15%. This is because if the water-absorbing agent content is less than 5%, water absorption in the extender pigment will not be sufficient, and if it exceeds 15%, the viscosity will increase and the practicality will decrease. The diisocyanates used in the present invention are limited to diphenylmethane diisocyanate (including crude diphenylmethane diisocyanate), tolylene diisocyanate, and isocyanate prepolymers. Regarding the reaction between terminally hydroxylated polybutadiene and diisocyanate, taking diisocyanate and tolylene diisocyanate as an example, this is a reaction between a bifunctional polyol and a bifunctional isocyanate, and usually the main chain extension is linear main chain extension. If ether polyol is used in combination, three-dimensional network bonds will frequently occur between polybutadienes, resulting in a cured product that is much harder than when it is not used in combination. The more a polyether polyol with a larger number of functional groups is used, or the more its added amount is increased, the frequency of occurrence of three-dimensional network bonds between polybutadienes increases, and a harder cured product is obtained. In other words, by selecting the number of functional groups, molecular weight, and amount added of the polyol in the composition, cured products with different elastic moduli can be obtained, and if used in combination with the polymer material filling effect of extender pigments, it is possible to control the elastic modulus over a wider range. be. An explanation of the embodiment will be given below. The manufacturing methods of Examples 1 to 4 (Table 1) are as follows: First, each component except crude diphenylmethane diisocyanate is homogeneously kneaded and dispersed in advance, and then a predetermined amount of crude diphenylmethane diisocyanate is added and mixed. Obtain a cured product with the performance shown in -2. As explained above, the physical and chemical performance of the present invention is close to that of urethane resin mortar and fully satisfies the required performance of the orbit, and in terms of cost, it is significantly lower than urethane resin mortar. It is inexpensive and exhibits significant practical effects.

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Claims (1)

[Scope of Claims] 1 Extender, a polycyclic aromatic hydrocarbon resin (average molecular weight 200 to 400), petroleum-based high boiling point hydrocarbon oil (average molecular weight 150 to 300), and terminal hydroxylated polybutadiene (average molecular weight 1000) ~3000), polyether polyol (average molecular weight 300~1000),
It has a composition of an organometallic catalyst, a water-absorbing agent, and a diisocyanate, and the extender pigment is 20 to 40% (important percentage, the same applies hereinafter), the polycyclic aromatic hydrocarbon resin is 30 to 50%, and the petroleum-based high-carbon resin is 30 to 50%. Boiling point hydrocarbon oil 5-15%, above-mentioned terminal hydroxylated polybutadiene
8 to 20% of the above polyether polyol, 1 to 10% of the above organometallic catalyst, 5 to 20% of the above water absorbing agent, and 3 to 15% of the above diisocyanate. .