JP2001207598A - Urethane coating waterproofing method - Google Patents

Abstract

(57) [Problem] To provide a waterproofing method capable of laminating a urethane film waterproofing material without requiring a long time for curing after applying a primer. SOLUTION: An isocyanate group-terminated prepolymer (a) obtained by reacting a polyisocyanate compound containing 4,4'-diphenylmethane diisocyanate with a polyoxyalkylene polyol, and an organic solvent (b)
And a urethane curing catalyst (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for waterproofing a urethane coating film on a mortar or concrete base such as a roof of a building, and more particularly, a method capable of being applied even in winter when the outside air is at low temperature and low humidity. About.

[0002]

2. Description of the Related Art Conventionally, as a urethane coating waterproofing method in the above-mentioned field, an isocyanate group-terminated prepolymer obtained by reacting polyoxypropylene polyol and tolylene diisocyanate as a primer is solidified with an organic solvent such as xylene. After using a solution having a viscosity of 10 to 100 cP (20 ° C.) diluted to a concentration of 20 to 60% by mass and applying this primer at 0.1 to 0.3 kg / m ² , a urethane coating waterproof material is laminated. The method has been adopted.

In this case, when the primer is applied, the organic solvent in the primer is volatilized, and at the same time, the prepolymer in the primer is moisture-cured due to the moisture in the air and the moisture contained in the concrete substrate, and the substrate is cured the next day. And firmly adhere to it, fulfilling the function as a primer. However, this is generally the case where the temperature of the outside air is 10 to 35 ° C., and when the temperature is lower than 0 ° C., such as in winter or in a cold area, the organic solvent is hard to volatilize, and the prepolymer is It took 5 to 20 days to cure with moisture and adhere to the substrate.

[0004]

As described above, in an environmental condition where the temperature is lower than 0 ° C., sufficient adhesive strength can be obtained even if the primer is applied to the base and the urethane coating waterproofing material is overcoated the next day. There was no problem.

[0005] Further, when a spray-type urethane coating waterproofing material of a super-fast curing type is overcoated in such a state, the exothermic reaction occurs at 60 to 90 ° C immediately after the application and the curing proceeds, so that the residual solvent volatilizes rapidly, There was a problem that the uncured primer layer foamed and the primer layer was easily peeled off.

For the above reasons, the conventional urethane coating waterproofing method is difficult to perform in a short period of time unless the outside air temperature is 10 ° C. or more and at least 5 ° C. or more. It took a long time.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended for use in applying a urethane coating waterproofing material on a base surface of a building frame to provide 4,4'-diphenylmethane diisocyanate. Isocyanate group-terminated prepolymer (a) obtained by reacting a polyisocyanate compound containing polyisocyanate with a polyoxyalkylene polyol, an organic solvent (b), and a urethane curing catalyst (c)
A urethane coating waterproofing method characterized by first applying a primer containing a urethane coating and laminating the urethane coating waterproofing material thereon.

According to the present invention, the use of the primer containing the specific isocyanate group-terminated prepolymer (a) enables the urethane coating on the day after the primer is applied even in a low-temperature environment atmosphere of, for example, 5 ° C. or less. The membrane waterproofing material can be laminated, and the construction period can be greatly reduced. Also, since the urethane coating waterproofing material is firmly adhered to the lower ground of the building frame via the primer,
Durability can be increased.

In the present invention, the organic solvent (b) contained in the primer is one or a mixture of two or more selected from the group consisting of xylene, toluene, ethyl acetate and butyl acetate; It is preferable that the primer contains 30 to 90% by mass of the organic solvent (b).

The urethane curing catalyst (c) contained in the primer is dibutyltin dilaurate, and the primer contains 0.001 to 1% by mass of the urethane curing catalyst (c). preferable.

Further, the polyisocyanate compound may be selected from the group consisting of tolylene diisocyanate and / or 2,4 ′ in addition to 4,4′-diphenylmethane diisocyanate.
-It is preferable that the composition contains diphenylmethane diisocyanate.

Further, the primer is provided on the base surface.
0.05-0.5kg / m ^TwoGood to apply
Good.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. As the base surface of a building frame to which the present invention is applied, a base surface made of mortar or concrete, such as a building roof or a veranda floor, is preferably applied.

The primers used in the present invention are (a) 4,
An isocyanate group-terminated prepolymer obtained by reacting 4′-diphenylmethane diisocyanate with a polyoxyalkylene polyol, (b) an organic solvent,
(C) a urethane curing catalyst.

In the above, the polyoxyalkylene polyol is usually produced by reacting a polyfunctional initiator with an alkylene oxide. The initiator referred to here is an active hydrogen compound having two or more active hydrogen atoms, and examples thereof include polyhydric alcohols, polyhydric phenols, alkanolamines, and amines. Specifically, polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, and bisphenol A Polyhydric phenols and the like are preferably employed. Examples of the alkylene oxide include ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and styrene oxide, with propylene oxide being particularly preferred.

The average number of hydroxyl groups of the polyoxyalkylene polyol is preferably 2 to 4. Particularly, it is 3 or less, most preferably 2.5 to 3. When the average number of hydroxyl groups is less than 2, the cured product of the primer is soft and the cured product has insufficient mechanical strength and adhesive strength. On the other hand, if it exceeds 4, the cured primer becomes too hard and the adhesive layer is easily broken, which is not preferable.

If the molecular weight of the polyoxyalkylene polyol is too small, the concentration of urethane bonds becomes too high,
It becomes difficult to dissolve in a solvent. However, even if the molecular weight is too large, the cured product becomes soft and the adhesive strength tends to be insufficient, so that the molecular weight per hydroxyl group is preferably 100 to 2,000, and particularly preferably 120 to 700.

Examples of the polyisocyanate compound used as a raw material of the isocyanate group-terminated prepolymer include aromatic and aliphatic compounds having an average of two or more isocyanate groups.
Polyisocyanates such as modified polyisocyanates are conceivable, but in the present invention, it is essential to use 4,4'-diphenylmethane diisocyanate which can be moisture-cured in a short time even at low temperature and low humidity. Thereby, there is an effect that the adhesiveness is not impaired even if the time until the application of the urethane coating waterproofing material of the top coat is left.

It should be noted that other polyisocyanate compounds can be used in combination with 4,4'-diphenylmethane diisocyanate. Examples of such polyisocyanate compounds include 2,4-tolylene diisocyanate and 2,4 tolylene diisocyanate.
Tolylene diisocyanate such as 6-tolylene diisocyanate and 2,4′-diphenylmethane diisocyanate are preferred. In this case, tolylene diisocyanate and / or 2,2 in the polyisocyanate compound
The mixing ratio of 4'-diphenylmethane diisocyanate is preferably 0 to 70% by mass, more preferably 10 to 70% by mass.
70% by mass.

When the amount of tolylene diisocyanate and / or 2,4'-diphenylmethane diisocyanate exceeds 70% by mass in the polyisocyanate compound, the effect of promoting the curability at low temperature by the urethane curing catalyst (c) decreases. In other words, 4,4′-diphenylmethane diisocyanate is contained in the polyisocyanate compound.
It is preferred that the content be 0% by mass or more.

When 4,4'-diphenylmethane diisocyanate is used in combination with another polyisocyanate compound, a polyoxyalkylene polyol is reacted with a polyisocyanate compound mixture obtained by mixing them at a predetermined ratio. Isocyanate group-terminated prepolymers may be obtained, or after separately synthesizing isocyanate group-terminated prepolymers from each polyisocyanate compound as raw materials, mixing the obtained isocyanate group-terminated prepolymers at a predetermined ratio. Is also good.

The isocyanate group-terminated polyurethane prepolymer (a) is reacted with the above-mentioned polyisocyanate compound, polyoxyalkylene polyol and an organic solvent (b) described below at 60 to 80 ° C. for several hours in a nitrogen atmosphere. Manufactured. The reaction ratio between the polyisocyanate compound and the polyoxyalkylene polyol is preferably set to a molar ratio of isocyanate group / hydroxyl group (hereinafter referred to as “NCO / OH ratio”) = 1.6 to 2.2. If the above ratio is less than 1.6, the viscosity of the obtained prepolymer becomes too high, and in some cases, it may be solidified in a gel state. On the other hand, if it exceeds 2.2, the cohesive strength of the resin is reduced, and the tack tends to remain even after the solvent is applied and the solvent is volatilized.
Further, the isocyanate group content of the obtained prepolymer solution is preferably 2 to 5% by mass. If it exceeds 5% by mass, foaming is likely to occur during moisture curing, and if it is less than 2% by mass, the adhesive strength tends to be insufficient.

As the organic solvent (b), general organic solvents except alcohols can be used, but those having a boiling point of 60 to 200 ° C. are preferable in consideration of workability and drying property. For example, xylene (boiling point 138 to 144 ° C), toluene (boiling point 111 ° C), ethyl acetate (boiling point 77 ° C),
Butyl acetate (boiling point 120-125 ° C), methyl ethyl ketone (boiling point 80 ° C), n-hexane (boiling point 69 ° C), cyclohexane (boiling point 81 ° C), n-heptane (boiling point 98
° C) and mineral spirits of petroleum-based solvents (15
2-196 ° C.) or a mixture of two or more selected from the group consisting of: Further, it is preferable that the primer contains 30 to 90% by mass of the organic solvent.

Further, as the urethane curing catalyst (c),
Organometallic catalysts such as organotin compounds and organolead compounds are preferred, and organotin compounds are particularly preferred. More preferred are dibutyltin dilaurate and stannas octoate, with dibutyltin dilaurate being most preferred. The addition amount of the urethane curing catalyst in the primer is 0.1%.
001 to 1% by mass is preferred. In the present invention, the curability at low temperatures can be promoted by combining the urethane curing catalyst (c).

The primer thus obtained has an isocyanate group content of 2 to 5% by mass and a viscosity of 10 to 100 cP
(20 ° C.) is preferred. Then, the primer is applied to the ground surface of the building frame with a roller or the like.
05 to 0.5 kg / m ² , preferably 0.1 to 0.3 k
g / m < ² > and apply uniformly. In this primer layer, moisture curing sufficiently proceeds even under conditions where the outside air temperature is 5 ° C. or lower, so that the urethane coating waterproof material can be overcoated the next day, and the construction period can be greatly reduced.

In the present invention, after the above primer is applied, when the urethane coating waterproofing material is overcoated, most of the isocyanate groups of the prepolymer in the primer are cured by moisture and turned into a resin, and some of the isocyanate groups remain. It is desirable to chemically bond with the urethane coating waterproofing material.

When such a primer is used, it easily reacts with the moisture of the base or the moisture in the air even when the outside air temperature is 5 ° C. or less, and exhibits sufficient strength and adhesive strength as a primer. Waterproofing material can be applied. Further, even if the urethane spray waterproofing material of the ultra-fast curing type is overcoated, the primer layer is sufficiently resinified, so that it does not foam and peel off.

The urethane coating waterproofing material used in the present invention may be any urethane liquid material capable of curing to form a coating film. Examples thereof include polyoxyalkylene polyol, tolylene diisocyanate, and 4,4 '. -One-part urethane coating waterproofing material which is mainly composed of isocyanate group-terminated polyurethane prepolymer reacted with diphenylmethane diisocyanate and reacts with atmospheric moisture by itself, or isocyanate group-terminated polyurethane polymer. A two-part urethane coating waterproofing material which is cured by mixing with an active hydrogen compound such as 4,4'-methylene (2-chloroaniline) or polyoxyalkylene polyol as a main agent and a curing agent, diethyltoluenediamine, polyoxy Active hydrogen compound composed of alkylene polyol and spray machine A spray type urethane waterproofing membrane material ultra fast curing type impinging mixed in a mixing chamber of the discharge port, can also be used in any type. However, it is preferable to use a urethane coating waterproofing material having a performance that meets the urethane rubber type 1 standard in JIS-A 6021 (coating waterproofing material for roof).

[0029]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Examples 1-4 and Comparative Examples 1-3
Was evaluated by the following method.

<Low-temperature curability> In a 5 ° C., 30% relative humidity atmosphere, 0.25 kg / m ² of various primers is applied to a 70 × 150 mm square, 20 mm thick mortar board (R5201-97) of JIS standard. did. The curing speed of the surface of the applied primer was confirmed by the change over time in the solubility of xylene. That is, three drops of xylene were dropped on the primer-coated surface and rubbed with a finger 30 seconds later, and the state of the coating film was observed. Evaluation: ◎: not dissolved, ○: slightly softened,
Δ: Somehow dissolved, ×: Easily dissolved.

<Low Temperature Adhesion Property> Under the above-mentioned temperature conditions, a hand-painted two-component urethane waterproofing material was applied 16 hours after the primer application, and the adhesive strength after 2 days was adjusted to 180 ° of 25 mm width.
It was measured by a peel test. As shown in FIG. 1, the 180 ° peel test was performed on the waterproof material layer 2 formed on the mortar plate 1.
Of the mortar plate 1 and the waterproofing material layer 2 in a 180 ° direction (unit:
N / 25 mm).

<High Temperature Adhesion Property> Two mortar plates similar to those described above were prepared, and the primer was applied in an atmosphere of 35 ° C. and a relative humidity of 60%. Was applied. Two days after the application of the waterproof material, that is, a total of three days and five days after the application of the primer, a 180 ° peel test of 25 mm width was performed on each sample to measure the adhesive strength.

Example 1 11.5 parts by mass (hereinafter simply referred to as "parts") of polyoxypropylene triol having a molecular weight of 420 (hereinafter referred to as "polyol A") obtained by adding propylene oxide to glycerin, After mixing 60 parts of xylene with 6.1 parts of polyoxypropylene diol having a molecular weight of 1,000 (hereinafter referred to as “polyol B”) obtained by adding propylene oxide to propylene glycol,
2.4 parts of 4,4′-diphenylmethane diisocyanate (NCO / OH ratio = 1.9) was reacted to obtain a prepolymer solution having an NCO content of 3.6% by mass and a viscosity of 40 cP at 20 ° C. To this, 0.01 part of dibutyltin dilaurate was added and used as a primer.

Example 2 12.6 parts of polyol A and 6.7 parts of polyol B were mixed with 60 parts of xylene, and 15.7 parts of 4,
4'-diphenylmethane diisocyanate and 5.0 parts of tolylene diisocyanate (2,4 units / 2,6 units = 80
/ 20 weight ratio) (NCO / OH ratio = 1.77), NCO content 3.3% by mass, viscosity 60 cP at 20 ° C.
Was obtained. To this, 0.1 part of dibutyltin dilaurate was added and used as a primer.

Example 3 11.6 parts of polyol A and 5.9 parts of polyol B were mixed with 60 parts of xylene, and a mixture of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate ( 50/50 mass ratio) 22.
5 parts (NCO / OH ratio = 1.90),
A prepolymer solution having a content of 3.6% by mass and a viscosity of 50 cP at 20 ° C. was obtained. To this, 0.1 part of dibutyltin dilaurate was added and used as a primer.

Example 4 One part of lead 2-ethylhexanoate (lead content: 24% by mass) was added to the prepolymer solution of Example 1 and used as a primer.

COMPARATIVE EXAMPLE 1 16.0 parts of polyol A and 8.0 parts of polyol B were mixed with 18.0 parts of a mass ratio of 2,4-tolylene diisocyanate to 2,6-tolylene diisocyanate of 80. /
A mixture of 20 (NCO / OH ratio = 4.55) was reacted and diluted with 58 parts of xylene to obtain a prepolymer solution having an NCO content of 3.1% by mass and a viscosity of 30 cP at 20 ° C. This was used as a primer.

Comparative Example 2 The prepolymer solution of Example 1 to which dibutyltin dilaurate was not added was used as a primer.

Comparative Example 3 One part of dibutyltin dilaurate was added to the prepolymer solution of Comparative Example 1 and used as a primer. Example 1
4. The evaluation results of Comparative Examples 1 to 3 are shown in Table 1 below.

[0040]

[Table 1]

From the results shown in Table 1, a primer containing a prepolymer (a) obtained by reacting 4,4'-diphenylmethane diisocyanate, an organic solvent (b), and a urethane curing catalyst (c) was used. Examples 1-4
Shows that the low-temperature curability is good, and the urethane coating waterproof material can be applied after at least 10 hours, preferably 16 hours after application. Further, Examples 1 to
It can be seen that when the primer No. 4 was used, the low-temperature adhesive property and the high-temperature adhesive property were also good. In contrast, Comparative Examples 1 to 3 have poor low-temperature curability and poor low-temperature adhesion.

[0042]

As described above, according to the present invention,
By using a polyisocyanate-terminated prepolymer obtained by reacting a polyisocyanate compound containing 4,4'-diphenylmethane diisocyanate with a polyoxyalkylene polyether, an organic solvent, and a primer containing a urethane curing catalyst, Even under low temperature environment such as winter, it can be moisture-cured quickly.For example, the next day, urethane coating waterproofing material can be applied, so the construction period can be significantly shortened, and urethane coating waterproofing material Can be firmly bonded.

[Brief description of the drawings]

FIG. 1 is a side view showing a 180 ° peel test method in evaluation tests of Examples and Comparative Examples of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 175/08 C09D 175/08 E02D 31/02 E02D 31/02 F-term (Reference) 4D075 BB92Z CA13 CA38 CA47 DA23 DB12 DC01 EA07 EA25 EA41 EB38 EC30 EC37 EC54 4J034 CA15 CB03 CB07 CC12 CC61 CC65 CC67 DA01 DB03 DB07 DG02 DG03 DG04 DG05 DG14 DG16 HA01 HA02 HA07 HA14 HC12 HC61 HC64 HC67 HC71 JA02 JA14 JA02 KA01 KB02 DG01281 KA01 KB02 DG01 JA56 JC41 KA04 MA07 NA04 NA23 PA14 PB05 PC04

Claims (5)

[Claims] 1. An isocyanate group terminal obtained by reacting a polyisocyanate compound containing 4,4'-diphenylmethane diisocyanate with a polyoxyalkylene polyol when applying a urethane coating waterproofing material to a base surface of a building frame. Prepolymer (a) and organic solvent (b)
And a primer containing a urethane curing catalyst (c) and a urethane coating waterproofing method, wherein the urethane coating waterproofing material is laminated thereon. 2. The organic solvent (b) is one or a mixture of two or more selected from the group consisting of xylene, toluene, ethyl acetate and butyl acetate, and the organic solvent (b) is contained in the primer. The urethane coating waterproofing method according to claim 1, wherein b) is contained in an amount of 30 to 90% by mass. 3. The urethane curing catalyst (c) contained in the primer is dibutyltin dilaurate, and the content of the urethane curing catalyst (c) in the primer is 0.001 to 1% by mass. The urethane coating waterproofing method according to claim 1 or 2. 4. The method according to claim 1, wherein the polyisocyanate compound is
The urethane coating waterproofing method according to any one of claims 1 to 3, further comprising tolylene diisocyanate and / or 2,4'-diphenylmethane diisocyanate in addition to 4'-diphenylmethane diisocyanate. 5. The method according to claim 1, wherein the primer is applied to the base surface in a range of from 0.1 to 10.
05~0.5kg / m ² is coated, urethane waterproofing membrane method according to any one of claims 1 to 4.