JP2001335741A - Two-component polyurethane waterproofing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-component polyurethane waterproofing material having excellent curability at low temperature and sufficient pot life at room temperature and preventing bleeding of a cured coating film. SOLUTION: The curing agent contains bis (methylthio) toluenediamine and a polyol, and the molar ratio of NH ₂ groups in the bis (methylthio) toluenediamine to OH groups in the polyol is 75 to 95/5 to 25. And a two-component polyurethane-based waterproofing material comprising a main ingredient mainly composed of an isocyanate-terminated polyurethane prepolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention has excellent curability especially at low temperatures, maintains a sufficient pot life at room temperature, and has excellent coating appearance after curing, mechanical strength and bleed resistance. The present invention relates to a two-component polyurethane waterproofing material.

[0002]

2. Description of the Related Art Due to its excellent flexibility, polyurethane elastomers are used for a wide range of building materials such as waterproofing materials, flooring materials, sealing materials and elastic pavement materials.

[0003] Generally, a polyurethane elastomer is a two-part composition which is cured at room temperature and comprises a main component mainly composed of an isocyanate group-terminated polyurethane prepolymer and a curing agent mainly composed of an active hydrogen compound.

[0004] For example, in the application of a waterproofing material, a main ingredient mainly composed of an isocyanate group-terminated polyurethane prepolymer obtained by reacting a polyoxypropylene polyol with tolylene diisocyanate, a polyoxypropylene polyol and 4,4'- The two-component type comprising a curing agent containing methylene bis (2-chloroaniline) (hereinafter referred to as MOCA) as a main component is mainly used.

[0005] Since MOCA is solid at normal temperature, as described above, 30 to 30 polyoxypropylene polyols are usually added to polyoxypropylene polyol.
It is used by dissolving it at a concentration of 50% by mass, but its reactivity with the isocyanate group of the base agent is not so high, and the use of a curing catalyst such as organometallic lead is indispensable to complete the reaction (curing) at room temperature. It is.

[0006] On the other hand, diethyltoluenediamine may be used as a curing agent at room temperature (20 to 25 ° C).
Since the curing speed is too fast and the pot life is not sufficient (more than 40 minutes) to maintain the pot life, it is usually diluted with a large amount of a plasticizer to maintain the pot life.

[0007]

However, in the above-mentioned two-pack type polyurethane waterproofing material, its curability largely depends on the moisture concentration in the atmosphere and the environmental temperature. For example, when MOCA is used as a curing agent, In particular, the curability is poor at low temperatures (5 ° C. or less), such as in winter, and it takes a very long time to cure even when the amount of the curing catalyst is increased. There was a problem that the balance with the working time was difficult to control.

On the other hand, when a combination of diethyltoluenediamine and a plasticizer is used as a curing agent, the problem of curability at low temperatures can be solved. However, in particular, the pot life at high temperatures in summer cannot be sufficiently maintained. Because a large amount of plasticizer is used, the cured coating film easily bleeds,
There were problems such as deterioration of the adhesiveness of the top coat applied thereon and tackiness remaining on the surface of the top coat.

Accordingly, an object of the present invention is to provide a two-pack polyurethane which has excellent curability even at low temperatures, can maintain a sufficient pot life even at room temperature, and does not cause bleeding of a cured coating film. It is to provide a system waterproofing material.

[0010]

In order to achieve the above object, a two-pack polyurethane waterproofing material of the present invention contains bis (methylthio) toluenediamine (a) and polyol (b) as active hydrogen compounds, and The molar ratio of the NH ₂ group in (a) to the OH group in (b) (NH ₂ group /
A curing agent (1) having an OH group) of 75 to 95/5 to 25,
And a main agent (2) mainly containing an isocyanate group-terminated polyurethane prepolymer obtained by reacting a polyol and a polyisocyanate.

According to the present invention, a two-part composition which has excellent curability even at low temperatures (5 ° C. or lower), can maintain a sufficient pot life even at room temperature, and does not cause bleeding of the cured coating film. Mold polyurethane waterproof material can be provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The curing agent (1) will be described below. The curing agent (1) contains bis (methylthio) toluenediamine (a) as an active hydrogen compound. The bis (methylthio) toluenediamine (a) is preferably a mixture of 3,5-bis (methylthio) -2,4-toluenediamine and 3,5-bis (methylthio) -2,6-toluenediamine.

Since bis (methylthio) toluenediamine (a) has a higher reactivity with isocyanate than MOCA and lower than diethyltoluenediamine, a plasticizer is frequently used by using it in combination with polyol (b) described later. Curability and pot life can be controlled in a well-balanced manner. However, when different aromatic diamines are used, the pot life and the range of curability are likely to be limited due to the reactivity inherent in the amine.

The curing agent (1) further contains a polyol (b) as an active hydrogen compound. Polyol (b)
Has a hydroxyl number of 2 to 4 and a hydroxyl value of 16 to 112 mg KOH
/ G of polyoxypropylene polyol is preferred. More preferably, the number of hydroxyl groups is 3, and the hydroxyl value is 20 to 56 mg KO.
H / g of polyoxypropylene polyol.

When the number of hydroxyl groups in the polyol (b) is less than 2, it becomes difficult to increase the molecular weight of the cured coating film, so that the curability deteriorates and the mechanical strength of the cured product becomes insufficient. On the other hand, when the number of hydroxyl groups exceeds 4, the crosslink density becomes too high, and the elongation performance of the cured product deteriorates. A particularly preferred number of hydroxyl groups is 2.5 to 3.

The polyol (b) has a hydroxyl value of 16
If it is less than 1, the viscosity of the polyol becomes too high, and if the hydroxyl value exceeds 112, the amount of the plasticizer is increased because the molecular weight is small, so that the amount of the plasticizer used is undesirably increased. More preferred hydroxyl value is 24 to
56.

In the present invention, the polyol (b) is obtained by reacting an initiator with an alkylene oxide such as propylene oxide (preferably only propylene oxide), and preferably has 2 to 4 hydroxyl groups. In addition, ethylene oxide is added to the polyol terminal portion in an amount of 5 to 20.
By increasing the primary OH conversion rate of the terminal hydroxyl group by reacting by mass%, the reactivity with isocyanate can be made faster, but the hydrophilicity of the obtained cured coating film becomes higher, and it is exposed to water. Swells easily. Therefore, it is preferable that the terminal portion does not contain an oxyethylene group.

The initiator referred to herein is an active hydrogen compound having 2 or more active hydrogen atoms, and specifically, such as ethylene glycol, dipropylene glycol, butanediol, glycerin, trimethylolpropane, and pentaerythritol. Examples include polyhydric alcohols, polyhydric phenols such as bisphenol A, polyhydric amines, and compounds obtained by adding a small amount of alkylene oxide thereto. In the present invention, polyhydric alcohols are preferred.

In the present invention, the NH ₂ group in the bis (methylthio) toluenediamine (a) is further combined with the NH ₂ group in the polyol (b) in order to maintain both a sufficient pot life and excellent curability. OH group molar ratio (NH ₂ group / OH
Group) is 75 to 95/5 to 25.
When the NH ₂ group / OH group exceeds 95, the polyol component in the curing agent is reduced, and a sufficient amount of filler cannot be mixed, so that a proper thixotropic property required for a waterproof material cannot be imparted.
It is not preferable because the mechanical strength and elongation of the obtained cured product are reduced and the cured product is apt to be brittle. On the other hand, when the NH ₂ group / OH group is 7
If it is less than 5, the curability at a low temperature (5 ° C. or lower) becomes extremely poor, which is not preferable. More preferably NH ₂ group / OH group is 85 to 92 / 8-15.

The curable component (1) preferably contains at least one additive selected from curing catalysts, fillers, pigments, plasticizers, solvents, and stabilizers.
In the present invention, a curing catalyst and a filler are particularly preferably used.

As the curing catalyst, organometallic lead which is easy to suppress curability and side reaction with moisture is preferable. As the organic metal lead, lead octylate is preferable. By using a curing catalyst, curability can be improved to the same extent as when diethyltoluenediamine is used in combination with a large amount of a plasticizer as a curable component. The compounding amount of the curing catalyst in the curing agent (1) is preferably 0.2 to 2.0% by mass,
0.8-1.5 mass% is more preferable.

Examples of the filler include calcium carbonate, talc, clay, silica, carbon and the like. In the present invention, calcium carbonate is particularly preferred. By using a filler, a suitable thixotropic property can be imparted,
Curability and coating film performance (hardness and strength) after curing can be improved. The compounding amount of the filler in the curing agent (1) is 30 to 75.
% By mass is preferable, and 40 to 68% by mass is more preferable.

By increasing the amount of the filler, the curability is increased, and the hardness and strength can be increased. But,
If the amount is more than 68% by mass, kneading becomes difficult, making it difficult to use as a waterproof material. If less than 40% by mass, the curability and the mechanical strength of the coating film become insufficient.

Examples of the pigment include inorganic pigments such as chromium oxide and titanium oxide, and organic pigments such as phthalocyanine pigments.

Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, dinonyl phthalate, diisononyl phthalate, dioctyl adipate, chlorinated paraffin, petroleum plasticizer and the like. In the present invention, dioctyl phthalate is particularly preferred. By using a plasticizer, the filler can be more uniformly and efficiently kneaded, and the surface appearance of the cured coating film can be improved. Curing agent (1)
Is preferably 25% by mass or less,
10-25 mass% is more preferable.

Examples of the solvent include aromatic hydrocarbons such as toluene and xylene, and aliphatic hydrocarbons such as n-heptane and n-decane.

Examples of the stabilizer include an antioxidant, an ultraviolet absorber and a dehydrating agent generally used for polyurethane resins.

Next, the main agent (2) will be described. The main agent (2) includes an isocyanate group-terminated polyurethane prepolymer obtained by reacting a polyol with a polyisocyanate.

The polyol is preferably a polyoxypropylene polyol. The number of hydroxyl groups of the polyol is preferably 2 to 4, preferably 3 or less, particularly 2.5 or less, and more preferably 2.1 to 2.4. 2 hydroxyl groups
If it is less than 4, it becomes difficult to increase the molecular weight of the cured coating film, so that the mechanical strength of the cured product is insufficient. If it exceeds 4, the crosslink density becomes too high, and the elongation performance of the cured product is deteriorated.

In the present invention, the polyol is preferably composed of a mixture of polyoxypropylene diol and polyoxypropylene triol, and the molar ratio is preferably 60 to 90/40 to 10.

The molecular weight of the polyol is preferably 200 to 7,000, more preferably 700 to 1,500, as the molecular weight per hydroxyl group, from the balance of the viscosity of the obtained prepolymer, the strength of the cured coating film, and the elongation performance.

The polyisocyanate includes:
Polyisocyanates such as aromatic, aliphatic, and modified polyisocyanates having two or more isocyanate groups are exemplified. In the present invention, tolylene diisocyanate is preferred from the viewpoint of the viscosity, curability, and mechanical strength of the cured coating film of the obtained prepolymer, and particularly, tolylene diisocyanate having a 2,4-isomer content of 80% by mass or more. Is preferred.

In the present invention, the isocyanate group-terminated polyurethane prepolymer has an isocyanate group content of 2
~ 5% by mass is preferred. If the isocyanate group content is more than 5% by mass, curing will be too fast, and the cured coating film will be too hard to exhibit sufficient elongation performance. On the other hand, when the isocyanate group content is less than 2% by mass, the mechanical strength of the cured coating film becomes weak, and the performance required as a waterproof material cannot be sufficiently exhibited.

The two-component polyurethane waterproofing material of the present invention comprises:
It is preferable to use the mixing ratio of the main agent (2) and the curing agent (1) in a mass ratio of 1 / 0.5 to 3;
More preferably, it is used in 2. When the mixing ratio of the curing agent is less than 0.5, the absolute amount of the filler becomes small, so that proper thixotropic properties as a waterproofing material cannot be exhibited. When the mixing ratio exceeds 3, the active hydrogen compound (bis (methylthio) toluene) in the curing agent is used. Since the amount of the diamine (a) and the polyol (b)) is reduced, a plasticizer, a solvent, a filler, and the like must be used extensively in order to adjust the curability and the pot life, which is not preferable.

In this case, the molar ratio of the isocyanate groups in the main agent (2) to the active hydrogen groups in the curing agent (1) is expressed by: NC
O group / (NH ₂ group + OH group)} is preferably 0.9 to 1.3.

[0036]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples (1 to 4) and Comparative Examples (1 to 8), but the present invention is not limited thereto. In each example, the polyols shown in Table 1 were used.

[0037]

[Table 1]

The performance of the samples obtained in each of the examples was evaluated by the following methods, and the results are shown in Table 2.

<Working time> In a laboratory at 23 ° C. and 50% RH, a constant viscosity (100
Pa · s) was measured. In addition, if the said arrival time was 40 minutes or more, it was determined that the construction could be performed sufficiently even in summer.

<Low-temperature curability> A waterproof material was applied on a slate plate outdoors at 2 ° C. and 30% RH (amount of application: 2 kg / m).
² ) The situation after 16 hours (the determination of tack and walking) was compared.

<Topcoat adhesion> 23 ° C., 50% R
In the laboratory of H, an acrylic urethane top coat was applied 24 hours after the application of the waterproof material (application amount 0.2
kg / m ² ), and the tack and adhesion of the top coat after 24 hours were observed.

<Coating physical properties> The mechanical properties of the cured coating were measured according to JIS-A6021 method. In Table 2, T
s indicates tensile strength (unit: N / mm ² ), and E indicates elongation at break (unit:%).

<Water Swelling Property> A cured coating film cut to a thickness of 1 mm and a diameter of 30 mm was immersed in water at 23 ° C. for 24 hours, and the diameter was measured.

Example 1 To 17 parts by mass of polyol A and 68 parts by mass of polyol B, 15 parts by mass of tolylene diisocyanate (2,4-
Isomer content 80% by mass) (NCO group / OH group = 2.0
3) was reacted to obtain an isocyanate group-terminated polyurethane prepolymer having an NCO group content of 3.6% by mass, which was used as a main component.

Bis (methylthio) toluenediamine-Ethyl Corporation, trade name "EtaCure 30"
0 "[3,5-bis (methylthio) -2,4-toluenediamine and 3,5-bis (methylthio) -2,6-
Mixture of toluenediamine], the same applies hereinafter. 7.5 parts by mass, 13.0 parts by mass of polyol C, 15.0 parts by mass of dioctyl phthalate, 5 parts by mass of xylene, 6 parts by mass of calcium carbonate
A liquid obtained by mixing 0 parts by mass, 3 parts by mass of a pigment paste, and 1.5 parts by mass of lead octylate (lead content: 24% by mass) was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1/1 ｛N
CO group / (NH ₂ group + OH group) = 1.1 ° and used as a waterproof material.

Example 2 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

Bis (methylthio) toluenediamine5.
8.85 parts by mass of polyol C, 15.85 parts by mass of dioctyl phthalate, 6 parts by mass of xylene, 60 parts by mass of calcium carbonate, 3 parts by mass of pigment paste, and 3 parts by mass of pigment paste, lead octylate (lead content: 24% by mass). A liquid obtained by mixing 5 parts by mass was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1 / 1.5.
It was blended so that {NCO group / (NH ₂ group + OH group) = 1.1} and used as a waterproof material.

Example 3 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

Bis (methylthio) toluenediamine5.
15.12 parts by mass of dioctyl phthalate, 5 parts by mass of xylene, 60 parts by mass of calcium carbonate, 3 parts by mass of pigment paste, and 3 parts by mass of lead octylate (lead content 24% by mass) based on 0 parts by mass and 10.38 parts by mass of polyol D. A liquid obtained by mixing 5 parts by mass was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1 / 1.5.
It was blended so that {NCO group / (NH ₂ group + OH group) = 1.1} and used as a waterproof material.

Example 4 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

Bis (methylthio) toluenediamine5.
0 parts by mass, 12.12 parts by mass of polyol E (NH ₂ group /
(OH group = 90/10) dioctyl phthalate 13.38
Parts by mass, xylene 5 parts by mass, calcium carbonate 60 parts by mass, pigment paste 3 parts by mass, lead octylate (lead content 24
(% By mass) A liquid obtained by mixing 1.5 parts by mass was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1 / 1.5.
It was blended so that {NCO group / (NH ₂ group + OH group) = 1.1} and used as a waterproof material.

Comparative Example 1 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

7.30 parts by weight of MOCA, polyol B2
3. Dioctyl phthalate was added to 1.04 parts by mass of the molten mixture.
A liquid obtained by mixing 66 parts by mass, 3 parts by mass of xylene, 60 parts by mass of calcium carbonate, 3 parts by mass of pigment paste, and 1 part by mass of lead octylate (lead content: 24% by mass) was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1/1 ｛N
CO groups / (NH ₂ groups + OH groups) = 1.13 ° and used as a waterproof material.

Comparative Example 2 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

7.30 parts by weight of MOCA, polyol B2
3. Dioctyl phthalate was added to 1.04 parts by mass of the molten mixture.
A liquid obtained by mixing 66 parts by mass, 60 parts by mass of calcium carbonate, 3 parts by mass of pigment paste, and 4 parts by mass of lead octylate (lead content: 24%) was used as a curing agent.

The main agent and the curing agent were mixed in a mass ratio of 1/1 ｛N
CO groups / (NH ₂ groups + OH groups) = 1.13 ° and used as a waterproof material.

Comparative Example 3 17.16 parts by mass of polyol A and 68.
65 parts by mass were reacted with 14.19 parts by mass of tolylene diisocyanate (95% by mass of 2,4-isomer) (NCO group / OH group = 1.90) to give an NCO group content of 3.90 parts by mass.
2% by mass of a prepolymer was obtained, which was used as a main ingredient.

A liquid obtained by mixing 33.92 parts by mass of dioctyl phthalate, 60 parts by mass of calcium carbonate, and 3 parts by mass of a pigment paste in 3.08 parts by mass of diethyltoluenediamine without a catalyst was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1/2 (N
CO group / NH ₂ group = 1.1) and used as a waterproof material.

Comparative Example 4 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

4.16 parts by weight of diethyltoluenediamine, 8.65 parts by weight of polyol C, 17.19 parts by weight of dioctyl phthalate, 6 parts by weight of xylene, 60 parts by weight of calcium carbonate, 3 parts by weight of pigment paste, lead octylate (lead A liquid obtained by mixing 1 part by mass (content 24%) was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1 / 1.5.
It was blended so that {NCO group / (NH ₂ group + OH group) = 1.1} and used as a waterproof material.

Comparative Example 5 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

6.24 parts by weight of MOCA, polyol C
To a molten mixture of 8.65 parts by mass and 15.11 parts by mass of dioctyl phthalate, 5 parts by mass of xylene and 6 parts of calcium carbonate
A liquid obtained by mixing 0 parts by mass, 3 parts by mass of a pigment paste, and 2 parts by mass of lead octylate (lead content: 24%) was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1 / 1.5.
It was blended so that {NCO group / (NH ₂ group + OH group) = 1.1} and used as a waterproof material.

Comparative Example 6 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

4.11 parts by mass of dimethylthiotoluenediamine, 8.4 parts by mass of dioctyl phthalate, 60 parts by mass of calcium carbonate, 3 parts by mass of pigment paste, 3 parts by mass of pigment paste, lead octylate (lead content: 24 parts by mass) %)
A liquid obtained by mixing 2 parts by mass was used as a curing agent.

The main agent and the curing agent were added in a mass ratio of 1 / 1.5.
It was blended so that {NCO group / (NH ₂ group + OH group) = 1.1} and used as a waterproof material.

Comparative Example 7 The same isocyanate group-terminated polyurethane prepolymer as in Example 1 was used as a main component.

Bis (methylthio) toluenediamine8.
33 parts by mass of dioctyl phthalate 20.17 parts by mass, xylene 7 parts by mass, calcium carbonate 60 parts by mass, pigment paste 3 parts by mass, lead octylate (lead content 24% by mass)
A liquid obtained by mixing 1.5 parts by mass was used as a curing agent.

The main agent and the curing agent are mixed in a mass ratio of 1/1 (N
CO group / NH ₂ group = 1.1) and used as a waterproof material.

[0077]

[Table 2]

As can be seen from Table 2, by using a curing agent (Examples 1 to 4) in which bis (methylthio) toluenediamine and a polyol are mixed in a specific range, a sufficient amount of plasticizer can be used without excessive use. It is possible to obtain a two-pack polyurethane waterproofing material having excellent curability at time and low temperature, and excellent in recoat adhesion and mechanical properties of a cured coating film. In particular, when a polyol containing no ethylene oxide in the polyol terminal portion is used as the polyol component of the curing agent (Examples 1 to 3), the cured coating film has no water swelling property and is very suitable for a waterproof material.

[0079]

As described above, according to the present invention,
It is possible to provide a two-pack polyurethane waterproof material which has excellent curability at low temperatures (5 ° C. or lower) and can maintain a sufficient pot life even at room temperature.

The two-component polyurethane waterproofing material of the present invention comprises:
Since no bleeding of the cured coating film occurs, the adhesion of the top coat is excellent, and no tack is generated. Therefore, the surface appearance of the waterproof coating film can be beautifully finished. Furthermore, the cured coating film has sufficient mechanical strength for use as a waterproof material.

Continued on the front page F term (reference) 4J034 BA02 BA06 CA01 CA03 CA04 CA05 CA11 CA15 CA31 CC11 CC12 HA01 HA07 HC11 HC12 HC22 HC46 HC52 QB13 QB15 RA07 RA08 RA10 4J038 DG091 DG131 DG291 GA13 JA47 KA03 KA04 NA01 NA11 NA26 PB05

Claims (4)

[Claims] 1. An active hydrogen compound containing bis (methylthio) toluenediamine (a) and a polyol (b), wherein an NH ₂ group in (a) and an OH in (b) are used.
Molar ratio with the group (NH ₂ group / OH group) is 75 to 95/5 to
25. A two-component polyurethane waterproofing material comprising: a curing agent (1), which is 25, and a main component (2) containing a isocyanate group-terminated polyurethane prepolymer as a main component obtained by reacting a polyol with a polyisocyanate. . 2. The polyol (b) has 2 to 2 hydroxyl groups.
4. The two-pack polyurethane waterproofing material according to claim 1, which is a polyoxypropylene polyol having a hydroxyl value of 16 to 112 mgKOH / g. 3. The two-component polyurethane waterproofing material according to claim 1, wherein the curing agent (1) further contains a curing catalyst. 4. The molar ratio (NCO group / (NH ₂ group + OH group)) of the NCO group in the main agent (2) to (NH ₂ group + OH group) in the curing agent (1) is 0.9 to 4. The two-pack polyurethane waterproofing material according to any one of claims 1 to 3, which is 1.3.