JP2001132075A - Adhering method for box culvert - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhering method for a box culvert, capable of obtaining a structural body (joint body) functioning for superior adherence force, waterproofing (waterstopping ability), deformation follow-up ability, impact resistance or the like. SOLUTION: This adhering method, in which a box culvert 1 and a base construction 2, or box culverts 1 can be adhered together with a moisture- hardening type urethane-based adhering agent 3, and the moisture hardening type urethane-based adhesive 3, is a moisture-hardening type urethane-based adhesive 3 which has as the main component urethane prepolymer, obtained by reacting polyol having a mean molecular weight of 3,000 to 20,000 with polyisocyanate compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a box culvert bonding method.

[0002]

2. Description of the Related Art Conventionally, an inorganic adhesive such as mortar has been used for bonding a box culvert to a base structure such as a base concrete in the soil or bonding between box culverts. However, inorganic adhesives such as mortar generally have a high elastic modulus and are brittle, so they can follow the distortion of the base structure due to vibrations on the road, deformation of the ground, etc., as well as falling objects from the road or rocks from the forest. There is a problem that the impact resistance against collapse of the structure is poor and the durability of the structure is poor.

[0003] Therefore, recently, in order to provide elasticity and impact resistance between the box culvert and the base structure or between the box culverts, between the box culvert and the base structure or between the box culverts. A method of sandwiching an elastic cushion material, for example,
As described in JP-A-679, by using a moisture-curable water-swellable paste-like polyurethane resin,
Methods for improving the elasticity, impact resistance, water stopping property, and the like between box culverts and between the box culvert and the base structure are being studied.

However, the elastic cushioning material has a problem that a sufficient effect cannot be obtained due to a weak adhesive force to the box culvert and the base structure. The water-swellable paste urethane resin is a main component. By carbon dioxide gas generated when urethane prepolymer is cured by moisture,
There is a problem that the adhesive strength and the cohesive strength of the cured product become insufficient as a result of the expansion and the formation of the missing hole.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a structure (joining) having excellent adhesive strength, waterproofness (water stoppage), deformation followability, impact resistance, and the like. It is an object of the present invention to provide a method for bonding a box culvert that can obtain a body.

[0006]

According to a first aspect of the present invention, there is provided a method of bonding a box culvert, wherein the box culvert is bonded to a base structure in the soil, or the box culverts are bonded to each other by a moisture-curable urethane-based adhesive. And

According to a second aspect of the present invention, there is provided a method for bonding a box culvert according to the first aspect, wherein the moisture-curable urethane-based adhesive is a polyol having a number average molecular weight of 3,000 to 20,000. And a polyisocyanate compound and a urethane prepolymer obtained as a main component.

[0008] The moisture-curable urethane-based adhesive used in the present invention is an adhesive obtained by reacting a polyol with a polyisocyanate compound and containing a urethane prepolymer having isocyanate groups at both molecular terminals as a main component. is there.

The above-mentioned moisture-curable urethane adhesive becomes a liquid or semi-solid or solid moisture-curable urethane adhesive at room temperature, depending on the kind of polyol used. The moisture-curable urethane adhesive that is liquid at room temperature may be applied and used as it is, and the semi-solid or solid moisture-curable urethane adhesive at room temperature may be heated and melted as necessary. To apply, use, or
For example, it may be applied and used as a solvent-type adhesive dissolved in an organic solvent such as dichloromethane, toluene, acetone, and cyclohexane.

The polyol used for the synthesis of the urethane prepolymer includes, for example, polyether polyol, polyester polyol, polyalkylene polyol, polycarbonate polyol and the like, and is preferably used. These polyols may be used alone or in combination of two or more.

Among the above polyols, polyether polyols having advantages such as being hardly crystallized and being easily permeable to moisture are more preferably used.

Examples of the polyether polyol include homopolymers such as ethylene glycol, propylene glycol, and tetramethylene glycol or copolymers thereof; one or more low molecular weight active hydrogen-containing compounds having two or more active hydrogens; Polyoxyethylene-propylene polyol random copolymer or block copolymer obtained by ring-opening polymerization of propylene oxide and ethylene oxide in the presence of two or more kinds; polyoxytetra obtained by ring-opening polymerization of tetrahydrofuran Methylene glycol and the like can be mentioned. These polyether polyols may be used alone or in combination of two or more.

The low-molecular-weight active hydrogen-containing compounds include, for example, diols such as ethylene glycol, propylene glycol, butylene glycol and 1,6-hexanediol; glycerin, trimethylolpropane,
Triols such as 1,2,6-hexanetriol; and amines such as ammonia, methylamine, ethylamine, propylamine and butylamine. These low molecular weight active hydrogen-containing compounds may be used alone or in combination of two or more.

The polyether polyol is not particularly limited, but has a number average molecular weight of 3000 to 20.
000 is preferable, and the number of hydroxyl groups is not limited to 1.000 as an active hydrogen source in one molecule.
Those having 5 to 5 are preferable, and those having 2 to 3 hydroxyl groups are more preferable.

In the present invention, polyether polyols having various number average molecular weights or hydroxyl groups may be used alone as long as the physical properties required for urethane prepolymers and moisture-curable urethane-based adhesives are not impaired. Good, or two or more types may be used in combination.

The polyester polyol includes, for example, terephthalic acid, isophthalic acid, 1,5-naphthalic acid, 2,6-naphthalic acid, succinic acid, glutaric acid,
Adipic acid, pimelic acid, suberic acid, azelaic acid,
Dicarboxylic acids such as sebacic acid, decamethylene dicarboxylic acid, dodecamethylene dicarboxylic acid and ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, Polyester polyols obtained by reaction with polyols such as 1,6-hexanediol, diethylene glycol and cyclohexanediol; and poly-ε-caprolactone polyols obtained by ring-opening polymerization of ε-caprolactam. These polyester polyols may be used alone or in combination of two or more.

Further, examples of the polyalkylene polyol include polybutadiene polyol, hydrogenated polybutadiene polyol, hydrogenated polyisoprene polyol and the like. These polyalkylene polyols may be used alone or in combination of two or more. Examples of the polycarbonate polyol include polyhexamethylene carbonate polyol and polycyclohexane dimethylene carbonate polyol. These polycarbonate polyols may be used alone or in combination of two or more.

In claim 2, the polyol for synthesizing the urethane prepolymer has a number average molecular weight of 300.
It is necessary to be 0 to 20,000, preferably 5
000-20,000, more preferably 5,000-
15000, particularly preferably 5000 to 1200.
0.

If the number average molecular weight of the polyol (the distance between the crosslinking points of the main chain of the urethane prepolymer) is less than 3000, the isocyanate group content in the moisture-curable urethane-based adhesive becomes relatively large, and The curing reaction may become violent, resulting in an increased amount of carbon dioxide gas.
Conversely, a polyol whose number average molecular weight exceeds 20,000 is
Since the viscosity becomes too high, the viscosity of the moisture-curable urethane-based adhesive becomes too high as a result, which may cause a problem in workability as an adhesive for on-site construction.

Examples of the polyisocyanate compound used for synthesizing the urethane prepolymer include tolylene diisocyanate, diphenylmethane diisocyanate (MDI), a liquid modification of MDI, hexamethylene diisocyanate, xylylene diisocyanate, cyclohexane phenylene diisocyanate, and naphthalene-1. ,
Examples thereof include 5-diisocyanate and the like, which are preferably used. Among them, MDI and its liquid modified products which are excellent in reactivity and advantageous in terms of safety and handling properties are more preferably used.

The method for synthesizing the urethane prepolymer is not particularly limited. For example, the polyol and the polyisocyanate compound may be prepared so that the equivalent ratio of the isocyanate group of the polyisocyanate compound to the hydroxyl group of the polyol is larger than 1. Mix in proportions, 6
By reacting at a temperature of about 0 to 100 ° C. for several hours, a desired urethane prepolymer can be obtained.

The moisture-curable urethane-based adhesive used in the present invention may have a viscosity or a viscosity as required within a range that does not impair the achievement of the object of the present invention, in addition to the urethane prepolymer as an essential component. A tackifying resin or a thermoplastic resin may be added to adjust the adhesion to the adherend or the initial cohesion. These tackifying resins and thermoplastic resins may be used alone or in combination.

Examples of the tackifying resin include a rosin resin, a terpene resin, an aliphatic petroleum resin, an alicyclic petroleum resin, and an aromatic petroleum resin, and are preferably used. A tackifier resin having a softening point of 90 to 150 ° C is more preferably used. These tackifying resins may be used alone or in combination of two or more.

The amount of the tackifying resin to be added is not particularly limited.
It is preferable that the amount of the tackifying resin is 200 parts by weight or less based on 0 parts by weight. If the amount of the tackifier resin is more than 200 parts by weight based on 100 parts by weight of the urethane prepolymer, the heat resistance at high temperatures may be reduced, or the resin may become brittle at low temperatures.

As the thermoplastic resin, for example, an ethylene-vinyl monomer copolymer having a melt index (MI) of 100 or more is preferably used.

Specific examples of the ethylene-vinyl monomer copolymer include ethylene- (meth) acrylic copolymers such as ethylene-vinyl acetate copolymer (EVA) and ethylene-n-butyl acrylate copolymer. Acid ester copolymers, ethylene- (meth) acrylic acid copolymers and the like can be mentioned. These ethylene-vinyl monomer copolymers may be used alone or in combination of two or more. Here, (meth) acryl means acryl or methacryl.

As the thermoplastic resin, styrene-butadiene-styrene block copolymer (SBS) and styrene-isoprene-styrene block copolymer (SI
S), hydrogenated SBS (SEBS), hydrogenated SIS (SE
For example, a thermoplastic block copolymer such as PS) or a polyolefin resin such as polypropylene, polyethylene, or α-olefin copolymer may be used. These thermoplastic block copolymers and polyolefin resins may be used alone or in combination.

The addition amount of these thermoplastic resins is not particularly limited, but the urethane prepolymer 1
The amount is preferably 100 parts by weight or less with respect to 00 parts by weight. If the amount of the thermoplastic resin exceeds 100 parts by weight based on 100 parts by weight of the urethane prepolymer, the viscosity of the moisture-curable urethane-based adhesive may be significantly increased, and the workability at the time of on-site construction may be reduced.

The moisture-curable urethane-based adhesive used in the present invention includes, in addition to the urethane prepolymer, which is an essential component, and the above-mentioned tackifying resin and thermoplastic resin which are optionally added, the present invention provides Adhesives such as carbon dioxide adsorbents, waxes such as paraffin wax and microcrystalline wax, inorganic or organic fillers, thixotropic agents, and silane coupling agents, as long as they do not hinder achievement of the task. Agents, curing catalysts such as tertiary amines and organometallic compounds, one or more of various additives such as antioxidants (antiaging agents), heat stabilizers, light stabilizers, coloring agents, organic solvents, etc. May be added.

Examples of the carbon dioxide adsorbent include aluminum oxide, magnesium sulfate, barium oxide and the like. These carbon dioxide adsorbents may be used alone or in combination of two or more.

The addition amount of the carbon dioxide adsorbent is not particularly limited, but is preferably 0.01 to 50 parts by weight of the carbon dioxide adsorbent based on 100 parts by weight of the urethane prepolymer. If the amount of the carbon dioxide adsorbent added is less than 0.01 part by weight per 100 parts by weight of the urethane prepolymer, a sufficient carbon dioxide adsorption effect may not be obtained. Even if the addition amount of the adsorbent exceeds 50 parts by weight, the viscosity of the moisture-curable urethane-based adhesive is remarkably increased even though the carbon dioxide adsorption effect is no longer improved, and workability at the time of on-site construction is improved. May drop.

The method for producing the moisture-curable urethane-based adhesive used in the present invention is not particularly limited. For example, a predetermined amount of the urethane prepolymer, which is an essential component, and a tackifying resin to be added if necessary. One or more predetermined amounts of the thermoplastic resin or various additives are weighed, and dehydrated at room temperature under a stream of an inert gas such as nitrogen gas or under reduced pressure using a mixer such as a mixer or a kneader. Alternatively, the desired moisture-curable urethane-based adhesive can be obtained by uniformly stirring and kneading while performing heat dehydration.

The method for applying the moisture-curable urethane-based adhesive thus obtained is not particularly limited. For example, an adhesive for on-site construction such as a spatula, a comb, a hand roll, a hand gun, a spray coater, etc. What is necessary is just to apply to a predetermined part of one surface or both surfaces of the adherend to be bonded in a desired pattern by using an application device generally used for applying the agent.

[0034]

According to the method for bonding box culverts of the present invention, a moisture-curable urethane-based adhesive, particularly, having a number average molecular weight of 300
Using a moisture-curable urethane-based adhesive having a urethane prepolymer as a main component obtained by reacting a polyol of 0 to 20,000 with a polyisocyanate compound, adhesion between the box culvert and the base structure in the soil or between box culverts Therefore, it is possible to obtain a structure (joined body) having both excellent adhesive strength, waterproofness (water stoppage), deformation followability, impact resistance, and the like.

[0035]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example of a method of bonding a box culvert to a base structure in soil according to the present invention, and FIG. 2 is a perspective view showing an example of a method of bonding box culverts according to the present invention.

The bonding between the box culvert 1 and the base structure 2 in the soil by the bonding method of the present invention is performed, for example, by applying a moisture-curable urethane-based adhesive 3 to the joint surface of the base structure 2 as shown in FIG. , And the box culvert 1 is superimposed thereon and joined. in this case,
The application of the moisture-curable urethane-based adhesive 3 may be performed on only one of the bonding surface of the base structure 2 and the bonding surface of the box culvert 1, or may be performed on both surfaces. Further, when one or more box culverts 1 are further stacked on the box culvert 1 joined to the base structure 2 and joined, the same procedure may be performed. still,
The base structure 2 referred to in the present invention may be the box culvert 1 itself.

The box culverts 1 are bonded to each other by the bonding method of the present invention, for example, as shown in FIG. 1 are sequentially joined and connected. In this case, the application of the moisture-curable urethane adhesive 3 may be performed on only one of the joining surface of the preceding box culvert 1 and the joining surface of the subsequent box culvert 1, or may be performed on both surfaces. May be.

[0038]

As described above, according to the bonding method of the present invention, a urethane obtained by reacting a moisture-curable urethane-based adhesive, particularly a polyol having a number average molecular weight of 3,000 to 20,000 with a polyisocyanate compound. Uses a moisture-curable urethane-based adhesive containing a prepolymer as a main component, so that the box culvert and the base structure in the soil combine excellent adhesion, waterproofness (water stoppage), deformation followability, impact resistance, etc. (Joined body) and a structure (joined body) between box culverts can be obtained.

[0039]

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a method of bonding a box culvert to a base structure in soil according to the present invention.

FIG. 2 is a perspective view showing an example of a method of bonding box culverts according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Box culvert 2 Base structure 3 Moisture-curable urethane-based adhesive 4 Tube (for example, fume tube)

Claims (2)

[Claims] 1. A method for bonding a box culvert, comprising bonding a box culvert to a base structure in soil or between box culverts using a moisture-curable urethane-based adhesive. 2. A moisture-curable urethane-based adhesive comprising a urethane prepolymer obtained by reacting a polyol having a number average molecular weight of 3,000 to 20,000 with a polyisocyanate compound as a main component. The method for bonding box culverts according to claim 1, wherein: