JP2005264565A - Elastic paving material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic paving material suppressing the detachment of a binder and a hard aggregate from the surface of an elastic aggregate even if being exposed outdoors over a long period of time and maintaining a high sliding friction coefficient for a long period of time with little lowering of the sliding friction coefficient of the elastic paving material in a wet state. <P>SOLUTION: This elastic paving material is formed using the following (A)-(D): (A) the elastic aggregate, (B) the hard aggregate, (C) the urethane-based binder containing a structure part derived from a hydroxyl group both end diene-based polymer, wherein the content of the structure part is set within a range of 30-70 wt% of the whole binder, and (D) carbon black. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an elastic pavement in which an elastic aggregate and a resin binder are mixed and laid on a roadbed (especially a roadway) or the like to form an elastic pavement.

  Conventional elastic pavement material is made by mixing resin binders such as urethane with elastic aggregates such as rubber chips obtained by pulverizing rubber products such as discarded tires of automobiles, molding into a mat shape, or laying on the road surface, It is formed by rolling using a heat roller or the like. In general, hard aggregates such as pebbles, sand, silica sand, and glass are used in combination with elastic aggregates such as rubber chips for the purpose of preventing slippage on rainy days on ordinary roads.

In addition, the resin binder that is a component of the elastic pavement material includes a urethane binder and an epoxy binder, which are used alone or in a blend, but generally a highly flexible urethane binder is used. (For example, refer to Patent Document 1). As such urethane binders, both one-component moisture-curing type and two-component curing type are generally used, and as both polyol components, ether-based polyols such as PPG (polypropylene glycol) are mainly used. Is used.
Japanese Patent Laid-Open No. 3-200851

  However, an ether urethane binder using an ether polyol such as PPG does not have sufficient adhesion to an elastic aggregate such as a rubber chip. In particular, when the elastic pavement is exposed to the outdoors for a long period of time, the binder is cured, and the adhesion with a rubber chip or the like is further deteriorated. When the vehicle passes over the elastic pavement with the adhesion between the binder and the rubber chip deteriorated in this way, the tire tread and the elastic pavement rub against each other, and the binder or hard aggregate is detached from the rubber chip surface. Therefore, the rubber surface is easily exposed. As a result, the sliding friction coefficient of the elastic pavement in a wet state is significantly lower than the value immediately after the molding, and the vehicle slips easily on the wet road surface. According to the road structure ordinance, the sliding friction coefficient when wet in the rain is required to be 0.33 or more (at 60 km / h), and considering a safer driving, the friction coefficient is 0.4 or more (60 km / h). h), more desirably 0.5 or more (60 km / h) is required.

  The present invention has been made in view of such circumstances, and even when exposed outdoors for a long period of time, it is possible to suppress the release of the binder and hard aggregate from the surface of the elastic aggregate, and the elastic pavement in a wet state An object of the present invention is to provide an elastic pavement that is capable of maintaining a high sliding friction coefficient for a long period of time with a small decrease in sliding friction coefficient.

In order to achieve the above object, the elastic pavement material of the present invention has a configuration in which the following (A) to (D) are used.
(A) Elastic aggregate.
(B) Hard aggregate.
(C) It contains a structural portion derived from a hydroxyl group-terminated diene-based polymer, and its content is set within a range of 30 to 70% by weight of the entire urethane-based binder, based on the hydroxyl-terminated diene-based polymer. Urethane binder.
(D) Carbon black.

  That is, the present inventors have conducted extensive research to obtain an elastic pavement that has good adhesion between the urethane binder and the elastic aggregate and can maintain a high sliding friction coefficient (μwet) for a long period of time. It has been found that the use of a diene polymer having hydroxyl groups at both ends (hydroxyl end-terminated diene polymer) improves the adhesion between the urethane binder and the elastic aggregate. And the content of the structure part induced | guided | derived from a hydroxyl-terminated diene-type polymer is a urethane-type binder set in the range of 30 to 70 weight% of the whole urethane-type binder on the basis of a hydroxyl-terminated diene polymer. It has been found that an elastic pavement made of a combination of elastic aggregate and hard aggregate can suppress the occurrence of vehicle slip on a wet road surface during rainfall. A patent application was filed (Japanese Patent Application No. 2002-314738). As a result of continuing research to further improve the content of the above-mentioned Japanese Patent Application No. 2002-314738, the present inventors have found that the binder film covering the hard aggregate may be decomposed and disappeared by long-term outdoor exposure. I found out that it was seen. As a result of further research, when carbon black is used in combination with the elastic aggregate, hard aggregate, and the specific urethane-based binder, a binder film made of the urethane-based binder is obtained due to the ultraviolet shielding effect of the carbon black. As a result of the suppression of decomposition, it has been found that separation of the hard aggregate can be suppressed and a high sliding friction coefficient (μwet) can be maintained for a long period of time, and the present invention has been achieved.

  Thus, since the elastic pavement of the present invention uses a binder that uses carbon black together with an elastic aggregate, a hard aggregate, and the specific urethane-based binder, the binder can be obtained by the ultraviolet shielding effect of carbon black. The decomposition of the film can be suppressed. As a result, since the separation of the hard aggregate can be suppressed, an effect that a high sliding friction coefficient (μwet) can be maintained for a long period is obtained. Therefore, the elastic pavement of the present invention hardly suppresses slippage of the vehicle on a wet road surface with almost no decrease in the sliding friction coefficient (μwet) during rainy weather when the vehicle is driven outdoors for a long period of time. it can.

  Further, when the blending amount of the hard aggregate is set within a range of 5 to 35% by weight of the total amount of the elastic aggregate, the hard aggregate, and the urethane binder, the sliding friction coefficient when wet (μwet) Can be further improved, and a decrease in strength can be suppressed.

  Moreover, when the silicon carbide which is especially excellent in adhesiveness is used as the said hard aggregate, the adhesiveness of silicon carbide and a urethane type binder can be improved more.

  Furthermore, when using a hard aggregate surface-treated with a silane coupling agent, the adhesion between the hard aggregate and the urethane binder is further improved, and the release of the hard aggregate can be suppressed over a long period of time. The coefficient of friction (μwet) can be maintained better for a longer period.

  Next, embodiments of the present invention will be described in detail.

  The elastic pavement material of the present invention comprises an elastic aggregate (component A), a hard aggregate (component B), the specific urethane-based binder (component C), and a carbon black (component D) binder. It is formed.

  In the present invention, the elastic pavement is formed using carbon black (component D) together with the components A to C, and this is the greatest feature.

  The above-mentioned elastic aggregate (component A) is not particularly limited, and rubber materials such as natural rubber and synthetic rubber, and synthetic resins having elasticity such as thermoplastic elastomer and foamed polyurethane, etc. are formed in a chip shape, granular shape, etc. What was pulverized into a shape is used. These may be used alone or in combination of two or more. The synthetic rubber is not particularly limited. For example, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene terpolymer (EPDM), butadiene rubber (BR), chloroprene. Examples thereof include rubber (CR) and blended rubbers thereof. Among these, rubber chips made from waste tires are preferably used from the viewpoint of resource reuse.

  Next, the hard aggregate (component B) used together with the elastic aggregate (component A) is not particularly limited. For example, inorganic materials such as crushed stone, silica sand, sand, silica, glass, silicon carbide, and nylon Examples thereof include organic materials such as resins and urethane resins. These may be used alone or in combination of two or more. Among these, silicon carbide is preferably used because it has excellent adhesion to the urethane binder (component C).

  The above-mentioned hard aggregate (component B) can be controlled by a silane coupling agent in that it can suppress the separation of the hard aggregate (component B) over a long period of time and can maintain a high sliding friction coefficient (μwet) for a longer period of time. You may use what was processed.

  In addition, as a hard aggregate (B component) of this invention, only one of the hard aggregate surface-treated with the silane coupling agent and the hard aggregate not surface-treated with the silane coupling agent are used. You may use, or you may use both together.

  The silane coupling agent used for the surface treatment is not particularly limited, and examples thereof include vinyl ethoxy silane, γ-aminopropyl triethoxy silane, and epoxy silane. These may be used alone or in combination of two or more.

  And the hard aggregate (B component) surface-treated with the silane coupling agent can be produced as follows, for example. That is, a methanol solution of a silane coupling agent [preferably, silane coupling agent: methanol = 1: 3 (weight ratio) to a predetermined amount (preferably 100 g) of hard aggregate (preferably silicon carbide). ] In a predetermined amount (preferably 10 g). Subsequently, after heat-treating under a predetermined condition (preferably, 120 ° C. for 15 minutes) and then air-drying, a hard aggregate (preferably silicon carbide) that has been surface-treated with a silane coupling agent can be obtained.

  The average particle size of the hard aggregate (component B) is not particularly limited, but is preferably in the range of 0.01 to 2.5 mm, particularly preferably in the range of 0.01 to 0.5 mm. It is. That is, when the average particle diameter of the hard aggregate (component B) is less than 0.01 mm, the workability of the elastic pavement tends to be deteriorated. This is because a large amount of addition is required because the friction coefficient is low.

  The amount of the hard aggregate (component B) is 5 to 35% by weight of the total amount of the elastic aggregate (component A), the hard aggregate (component B), and the urethane binder (component C). It is preferable to set within the range, and particularly preferably within the range of 15 to 30% by weight. That is, when the amount of the hard aggregate (component B) is less than 5% by weight, the sliding friction coefficient (μwet) at the time of wetting tends to be too small, and conversely, the hard aggregate (component B) It is because the tendency for the intensity | strength of elastic pavement to fall will be seen when the compounding quantity of exceeds 35 weight%.

  As said specific urethane type binder (C component) used with the said elastic aggregate (A component) and a hard aggregate (B component), the hydroxyl group both terminal diene type polymer of a polyol component, and a polyisocyanate component are mentioned, for example. Examples thereof include urethane prepolymers obtained by reaction.

  Examples of the hydroxyl-terminated diene-based polymer of the polyol component include hydroxyl-terminated polybutadiene and hydroxyl-terminated polyisoprene, and these may be used alone or in combination of two or more. Among these, it is preferable to use polybutadiene having both hydroxyl groups since the adhesion between the urethane binder (C component) and the elastic aggregate (component A) is enhanced. The reason for this is not clear, but the molecular skeleton of the hydroxyl-terminated polybutadiene is the same as or similar to the molecular skeleton of polybutadiene and natural rubber used in rubber materials such as tires. Because of the close compatibility and high compatibility, it is considered that the compatibility between the hydroxyl-terminated polybutadiene and the rubber material, the wettability is improved, and the adhesiveness is increased.

  The polyisocyanate component used together with the polyol component is not particularly limited, and examples thereof include 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tridiene. Diisocyanate (2,6-TDI), 3,3′-vitrylene-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, 2,4-tolylene diisocyanate uretidinedione ( 2,4-TDI dimer), 1,5-naphthylene diisocyanate, metaphenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), carbodiimide-modified MD , Orthotoluidine diisocyanate, xylene diisocyanate, paraphenylene diisocyanate, lysine diisocyanate methyl ester, triphenylmethane-4,4 ′, 4 ″ -triisocyanate, polymeric MDI, etc. These may be used alone or in combination of two or more. It is done.

  The urethane-based binder (component C) is “the content of the structural portion derived from the hydroxyl-terminated diene-based polymer based on the hydroxyl-terminated diene-based polymer (diene-based polymer content)”. What is set within the range of 30 to 70% by weight must be used, and preferably the diene polymer content is within the range of 30 to 50% by weight of the entire urethane binder. That is, when the diene polymer content is less than 30% by weight, the adhesiveness with the elastic aggregate (component A) such as rubber chips deteriorates. Conversely, when the diene polymer content exceeds 70% by weight, This is because the strength of the pavement material decreases.

  The above-described diene polymer content is represented by the following formula. Diene polymer content = (weight of hydroxyl-terminated diene polymer) / (weight of polyol component + weight of polyisocyanate component). The weight of the polyol component is usually the weight of the hydroxyl group-terminated diene polymer, but as described later, together with the hydroxyl group-terminated diene polymer, polypropylene glycol (PPG) or polytetramethylene ether glycol (PTMEG) is used. When used in combination, the total weight of these is the weight of the polyol component.

  The urethane-based binder (component C) in which the diene polymer content is set within a specific range comprises a hydroxyl group-terminated diene polymer that is a polyol component and a polyisocyanate component on a weight basis. It can be obtained by blending and synthesizing within the range of system polymer / polyisocyanate component = 30/70 to 70/30.

  The urethane-based binder (component C) has a diene polymer content within a predetermined range, and as a polyol component, together with the hydroxyl group-terminated diene polymer, polypropylene glycol (PPG), polytetramethylene ether. Glycol (PTMEG) or the like may be used in combination.

  The blending amount of the urethane binder (C component) is in the range of 5 to 30% by weight of the total amount of the elastic aggregate (component A), hard aggregate (component B) and urethane binder (component C). It is preferable to set it to be within a range of 15 to 25% by weight. That is, when the blending amount of the urethane binder (C component) is less than 5% by weight, the strength of the elastic pavement tends to decrease, and conversely, the blending amount of the urethane binder (C component) is low. This is because when it exceeds 30% by weight, workability and workability tend to deteriorate.

  In the present invention, a binder component material other than the urethane type, for example, a binder component material such as an epoxy type or an asphalt type may be used in combination with the specific urethane type binder (component C).

  Next, carbon black (D component) used together with the elastic aggregate (component A), hard aggregate (component B), and specific urethane binder (component C) is not particularly limited. From the viewpoint of good dispersibility in a specific urethane-based binder (component C), carbon black for color is preferably used. Examples of the carbon black for color include various grades such as HCC, HCF, MCC, MCF, LFF, MFF (LFI), and RCF (RCC), and are used alone or in combination of two or more. . Among these, RCF grade carbon black for color is suitably used because it is excellent in dispersibility and ultraviolet shielding effect. Specific examples of the carbon black for RCF grade color include Toka Black # 7350 / F manufactured by Tokai Carbon Co., Ltd.

  The blending amount of the carbon black (component D) is in the range of 1 to 30% by weight of the total amount of the specific urethane binder (component C) and the carbon black (component D) (solid content excluding the solvent). It is preferable to set it to be within a range of 5 to 15% by weight. That is, when the blending amount of the carbon black (component D) is less than 1% by weight, there is a tendency that the decomposition of the binder film cannot be sufficiently suppressed because the ultraviolet shielding effect is small. If the blending amount exceeds 30% by weight, the viscosity of the binder liquid becomes too high, and the workability tends to be deteriorated, and the binder film becomes hard and has an influence such as cracking.

  The elastic pavement material of the present invention can be produced, for example, as follows. That is, the elastic aggregate (component A), hard aggregate (component B), specific urethane binder (component C), and carbon black (component D) are mixed at a predetermined ratio using a stirrer. The mixture (binder) is put into a mold, and then the mold is heat-treated with a hot press under a predetermined condition (for example, at 150 ° C. for 20 minutes) to give a plate-like (thickness 20 to 50 mm) elasticity. A paving material can be produced. However, the molding method and processing conditions (temperature and time) are not limited thereto. As shown in the examples described later, a urethane-based binder (C component) in which carbon black (D component) is blended at a predetermined ratio is prepared in advance, and the desired elastic pavement material is used as a binder component material. Can be produced.

  The elastic pavement of the present invention is a mixture of the above-mentioned elastic aggregate (A component), hard aggregate (B component), specific urethane binder (C component), and carbon black (D component), It is also possible to produce the sheet by laying it on the road surface and then rolling and compacting it using a heat roller or the like.

  The elastic pavement material of the present invention preferably has a porosity of 30 to 50%, particularly preferably a porosity of 35 to 45%. Note that the porosity is calculated by, for example, the following formula (1).

  The elastic pavement material of the present invention can be formed as follows, for example. That is, as shown in FIG. 1, by laying the elastic pavement 1 of the present invention on the roadbed 3 such as concrete or asphalt provided on the ground 4 using an adhesive 2 such as epoxy or urethane, A drainable elastic pavement structure can be formed. However, the laying method, the bonding method, and the adhesive are not particularly limited. As described above, after the above-mentioned mixture of components A to D is laid on the road surface, it is rolled using a heat roller or the like. It can also be formed by molding.

  The elastic pavement material of the present invention is not limited to the single layer structure as shown in FIG. 1, but has a multilayer structure of two or more layers formed by laminating layers having different hardness in the thickness direction. There is no problem. In this case, the surface layer (uppermost layer) of the multilayer structure is composed of the elastic aggregate (component A), the hard aggregate (component B), a specific urethane binder (component C), and carbon black (component D). It is preferable that it is formed by using.

  The use of the elastic pavement material of the present invention is not limited to road use, and can be used for, for example, a promenade or a stadium field.

  Next, examples will be described together with comparative examples.

  First, prior to the examples and comparative examples, the binder component materials shown below were prepared.

[Urethane binder]
Several types of hydroxyl group-terminated polybutadiene are reacted with hydroxyl-terminated polybutadiene, which is a polyol component, and MDI, which is a polyisocyanate component. A urethane-based binder was prepared. Next, RCF grade color carbon black (Tokai Black # 7350 / F, average particle size 28 nm) was blended with the obtained urethane binder to prepare a carbon black-containing urethane binder. . The PB content (% by weight) in the urethane binder and the carbon black content (% by weight) in the carbon black-containing urethane binder (solid content excluding the solvent) are shown in Tables 1 to 3 below. The results are also shown in Table 3.

(Elastic aggregate)
Hijiki-like rubber chips (average thickness: 0.5 to 1.5 mm, average length: 3 to 10 mm)

[Hard aggregate a]
Silicon carbide [manufactured by Shinano Electric Smelting Co., Shinano Random GC, particle size: F120 (No.), 100 to 150 μm]

[Hard aggregate b]
Methanol 5% solution of silane coupling agent (manufactured by LORD, AP-133) with respect to 100 g of silicon carbide [manufactured by Shinano Electric Smelting Co., Shinano Random GC, particle size: F120 (No.), 100 to 150 μm] [AP -133: methanol = 1: 3 (weight ratio)] was added and stirred. Subsequently, after heat-treating at 120 ° C. for 15 minutes, it was air-dried to produce silicon carbide having a surface treated with a silane coupling agent.

[Examples 1-13, Comparative Examples 1-3]
After blending each component shown in Tables 1 to 3 below in the proportions shown in the same table and stirring and mixing, the mixture is calculated so as to have a predetermined porosity, and put into a mold at 150 ° C. for 20 minutes. A flat elastic paving material (thickness 30 mm) was produced by hot pressing. In Example 8, a flat elastic paving material (thickness 30 mm) having a two-layer structure of a surface layer (thickness 15 mm) and a lower layer (thickness 15 mm) was produced.

  Using the elastic paving materials of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Tables 1 to 3 below.

[Hard aggregate content]
As described above, the content (% by weight) of the hard aggregate in the total amount of the elastic aggregate, the hard aggregate, and the urethane binder is shown.

[Porosity]
It measured according to the above-mentioned formula (1).

[Processability of binder]
◯ indicates that the dispersibility is not particularly problematic when the material is stirred, Δ indicates that the dispersibility is inferior but stirring is possible, and × indicates that the dispersibility is extremely deteriorated when the material is stirred.

[Adhesion]
The adhesiveness between the elastic aggregate and the urethane binder was evaluated by replacing it with the following T-shaped peel test. That is, a natural rubber-based vulcanized rubber sheet is prepared as a substitute for the elastic aggregate, and a urethane-based binder is applied to the surface and thermally cured to form a urethane-based binder on the surface of the natural rubber-based vulcanized rubber sheet. A binder layer was formed. Next, a T-shaped peel test was performed to peel the natural rubber-based vulcanized rubber sheet and a binder layer made of a urethane-based binder. In the evaluation, ◎ indicates that the adhesiveness is extremely good and the base material is broken, ◯ indicates that the base material is broken, Δ indicates that the base material breakage and interfacial peeling coexist, and x indicates that the interfacial peeling occurs.

〔Tensile strength〕
A surface layer portion 10 mm of each elastic pavement was cut out, and the tensile strength (MPa) was measured according to JIS K 6251.

[Remaining amount of hard aggregate]
After each of the elastic pavement materials was exposed outdoors (6 months and 1 year), DRY measurement was performed 10 times at a speed of 80 km / h using a DF tester (manufactured by Nihon Sangyo Co., Ltd.) to perform surface friction. Next, the test piece of rubber piece was contacted and rotated 10 times at a speed of 60 km / h on the surface for surface friction, and the remaining amount of hard aggregate on the surface of the elastic pavement was visually observed. Evaluation is the same as in the initial state with no omission of hard aggregates, ◯ for those with little omission of hard aggregates, △ for those with almost no omission of hard aggregates, and hard aggregates omission, The case where even the binder was worn and the rubber surface was exposed was marked with x.

[Sliding friction coefficient when wet (μwet)]
A flat test piece having a size of 50 × 50 cm and a thickness of 3 cm was prepared. After leaving it to stand at room temperature for 3 days or more, water was allowed to flow on the surface of the test piece, and the sliding friction coefficient when wet in the region of 80 km / h or less. (Μwet) was measured according to ASTM E1911-98 using a DF tester (manufactured by Nihon Sangyo Co., Ltd.), and the value at a speed of 60 km / h was read to obtain a measured value. In addition, the sliding friction coefficient (μwet) when wet is measured 10 times after the outdoor exposure (6 months and 1 year) using a DF tester (manufactured by Nihon Sangyo Co., Ltd.) at 80 km / h. The test was carried out for each of those subjected to surface friction and those subjected to neither outdoor exposure nor surface friction (initial value).

  From the above results, all of the example products have good adhesion between the hard aggregate and elastic aggregate and the urethane binder, almost no loss of the hard aggregate, and a high sliding friction coefficient (μwet) for a long time. I was able to maintain it. In addition, the products of Examples 9 to 13 using the hard aggregate b whose surface was treated with a silane coupling agent were particularly excellent in adhesion. Even when carbon black was blended in the urethane binder together with the elastic aggregate and the hard aggregate without including carbon black in the urethane binder, the same excellent effect as in Example 1 was obtained.

  On the other hand, in Comparative Example 1 product, the PB content in the urethane-based binder is too small, so the adhesion between the elastic aggregate and the urethane-based binder is slightly inferior, and the hard aggregate almost falls off, and the initial The sliding friction coefficient (μwet) could not be maintained for a long time. In Comparative Example 2 products, the PB content in the urethane-based binder was too high, so the strength decreased and the processability of the binder deteriorated. Since the product of Comparative Example 3 did not contain hard aggregate, the initial sliding friction coefficient (μwet) was remarkably low.

  The elastic pavement material of the present invention is not limited to road use, and can be used for, for example, a promenade or a field of a stadium.

It is sectional drawing which shows the elastic pavement structure using the elastic pavement material of this invention.

Explanation of symbols

1 Elastic pavement material 2 Adhesive 3 Roadbed 4 Ground

Claims (4)

The elastic pavement characterized by using the following (A)-(D).
(A) Elastic aggregate.
(B) Hard aggregate.
(C) It contains a structural portion derived from a hydroxyl group-terminated diene-based polymer, and its content is set within a range of 30 to 70% by weight of the entire urethane-based binder, based on the hydroxyl-terminated diene-based polymer. Urethane binder.
(D) Carbon black.   The elastic pavement according to claim 1, wherein the blending amount of the hard aggregate (B) is in the range of 5 to 35% by weight of the total amount of (A) to (C).   The elastic pavement according to claim 1 or 2, wherein the hard aggregate (B) is silicon carbide.   The elastic pavement according to any one of claims 1 to 3, wherein the hard aggregate (B) is surface-treated with a silane coupling agent.