JPH1036472A - Two-pack water-proofing material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-pack water-proofing material composition which gives a coating film having excellent mechanical properties. SOLUTION: The composition, which is curable at ordinary temp., is constituted of a main ingredient comprising an isocyanateterminated polyurethane prepolymer obtained by reacting a polyoxyalkylene polyol with a polyisocyanate, and a hardener comprising an active hydrogen compound. The content of the polyisocyanate remaining unreacted in the prepolymer is 1wt.% or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-pack type waterproofing composition which cures at room temperature and has excellent curability, appearance of cured coating, mechanical strength and heat resistance.

[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] This polyurethane elastomer is usually
It is a two-pack type composition that cures at room temperature and comprises a main component mainly composed of an isocyanate group-terminated polyurethane prepolymer and a curing agent composed of an active hydrogen compound. For use as a waterproofing material, the main component is an isocyanate group-terminated polyurethane prepolymer obtained by the reaction of polyoxypropylene polyol with tolylene diisocyanate, and the main components are polyol and 4,4'-methylenebis (2-chloroaniline). The two-component type comprising a curing agent component is still mainstream at present.

[0004]

Conventionally, tolylene diisocyanate used in an isocyanate group-terminated polyurethane prepolymer as a main component has a 2,4-isomer content of 8%.
The mainstream is 0% by weight. Usually, in order to keep the viscosity low, the equivalent ratio of tolylene diisocyanate to polyol is in the range of NCO group / OH group = 2 to 2.2.

However, in such a prepolymer, 1 to 4% by weight of unreacted tolylene diisocyanate is present.
When the temperature is high in summer, tolylene diisocyanate odor is generated, which is not preferable in terms of environmental hygiene.

In the course of the reaction with the curing agent, the reaction between the unreacted tolylene diisocyanate and the amine compound in the curing agent occurs first, and the reaction with the isocyanate group of the main chain of the polyurethane prepolymer is delayed, so that the polyurea is not reacted. A large number of hard segments are generated. This has a great effect on the mechanical properties of the obtained coating film, and also impairs the elongation performance and mechanical strength required for the waterproof material.

[0007]

The present invention is the following invention which has solved the above-mentioned problems. A room-temperature curable composition comprising a main component containing an isocyanate group-terminated polyurethane prepolymer obtained by reacting a polyol containing a polyoxyalkylene polyol as a main component with a polyisocyanate, and a curing agent component containing an active hydrogen compound. A two-part waterproofing composition, wherein the content of unreacted polyisocyanate in the isocyanate group-terminated polyurethane prepolymer is 1% by weight or less.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The polyoxyalkylene polyol used as the main ingredient of the present invention is usually produced by reacting a polyfunctional initiator with an alkylene oxide. The initiator referred to here is an active hydrogen compound having an average functional group number of 2 or more, and specific examples include ethylene glycol, dipropylene glycol, butanediol, glycerin, trimethylolpropane, pentaerythritol, and bisphenol A.

The alkylene oxide is ethylene oxide,
Propylene oxide, 1,2-butylene oxide, 2,
3-butylene oxide, styrene oxide and the like,
Particularly, propylene oxide or a combination of propylene oxide and ethylene oxide is preferred.

A particularly preferred polyoxyalkylene polyol is a polyoxypropylene polyol in which propylene oxide residues (ie, oxypropylene groups) obtained mainly by using propylene oxide account for 80% by weight or more of all alkylene oxide residues. is there.

The number of hydroxyl groups of the polyol is preferably 2 to 4. In particular, it is 3 or less, most preferably more than 2 and 2.5 or less. If the average number of hydroxyl groups is less than 2, it becomes difficult to increase the molecular weight of the cured coating film, so that the cured product has insufficient mechanical strength. If it exceeds 4, the crosslink density becomes too high, and the elongation performance of the cured product deteriorates.

[0012] If the molecular weight of the polyoxyalkylene polyol is too small, the elongation of the cured product will be extremely poor, making it unsuitable for use as a waterproof material. However, if the molecular weight of the polyol is too high, the viscosity of the obtained polyurethane prepolymer may increase, and the mechanical strength of the cured product may be insufficient. Therefore, the molecular weight per hydroxyl group of the polyol is 20.
It is preferably 0 to 7,000, and 500 to 3.0.
00 is preferable, and 700 to 1,500 is particularly preferable.

Examples of the polyisocyanate include aromatic, aliphatic and modified polyisocyanates having two or more isocyanate groups on average. Tolylene diisocyanate is preferred in view of the viscosity, curability, and mechanical strength of the cured coating film of the obtained isocyanate group-terminated polyurethane prepolymer. Furthermore, the 2,4-isomer content is 95
Preference is given to tolylene diisocyanate in an amount of at least% by weight.

In the present invention, the content of unreacted polyisocyanate in the isocyanate group-terminated polyurethane prepolymer is 1% by weight or less. As a method for obtaining a polyurethane prepolymer, one method is to produce a isocyanate group-terminated polyurethane prepolymer by reacting a polyol containing a polyoxyalkylene polyol as a main component with a polyisocyanate in the presence of a catalyst.

In this case, the catalyst is preferably a tertiary amine and / or an organic metal catalyst. As tertiary amines, triethylamine, dimethylcyclohexylamine, 1,4
-Diazabicyclo [2.2.2] octane, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-
Tertiary amines such as diazabicyclo [5.4.0] undec-7-ene and diethylbenzylamine.

Examples of the organometallic catalyst include an organic acid such as tin octoate, tin naphthenate, dibutyltin dilaurate, and zinc octoate, and Sn, Co, Ni, Fe, Zn, and the like.
And salts with metals such as Pb. In this case NC
It is preferable that the equivalent ratio of O group / OH group is 1.6 or more and 2.1 or less.

In the present invention, the isocyanate group-terminated polyurethane prepolymer can also be produced by reacting a polyol containing a polyoxyalkylene polyol as a main component with a polyisocyanate in the absence of a catalyst.
In this case, the equivalent ratio of NCO group / OH group exceeds 1.5 and 2
It is necessary to make the reaction within the range below. In the present invention, it is particularly preferable that a polyol containing a polyoxyalkylene polyol as a main component is reacted with a polyisocyanate in the presence of a catalyst, and the equivalent ratio of NCO group / OH group is more than 1.5 and less than 2. preferable.

The polyol and the polyisocyanate are preferably produced by reacting at 80 to 100 ° C. for several hours in a nitrogen atmosphere in the presence of a catalyst. More preferably, it is conceivable to first charge the polyisocyanate into the reactor and then react at 60 to 100 ° C. while gradually adding the polyol.

At this time, the free isocyanate group content of the polyurethane prepolymer can be arbitrarily changed depending on the molecular weight of the polyol, but is preferably 1 to 8% by weight. 8
If the amount is more than 10% by weight, the curing will be too fast, and the resulting coating film will be hard, and sufficient elongation performance will not be exhibited. 1% by weight
If it is less than 10, the mechanical strength of the coating film becomes weak, and it becomes difficult to exhibit the performance required as a waterproof material. More preferably, 2.0 to
4.0% by weight.

It is preferable that at least one of the active hydrogen compounds in the curing agent component is an amine compound having two or more primary or secondary amino groups. Diethyltoluenediamine, 4,4'-methylenebis (2-chloroaniline)
Etc. can be used. Diethyltoluenediamine is particularly preferred. Other active hydrogen compounds can also be used in combination, such as polyols such as polyether polyols.

When diethyltoluenediamine is used, 4,4'-methylenebis (2-chloroaniline)
When mixing components having different reactivities such as and other polyols, the balance of the reactivity with the main agent tends to deteriorate, and the curability tends to be significantly slow, and the curability especially at low temperatures tends to deteriorate. . Further, the obtained cured coating film tends to have low mechanical strength and insufficient heat resistance. It is particularly preferred that it is substantially only diethyltoluenediamine.

Diethyltoluenediamine is liquid at normal temperature, has excellent compatibility with plasticizers and the like, and can be optionally diluted.

The diethyltoluenediamine includes 3,5-diethyltoluene-2,4-diamine and 3,5-diethyltoluene-2,6-diamine. It is preferably a mixture, especially 3,5-diethyltoluene-2,4.
-It is preferable that the diamine is contained in an amount of 70 to 85% by weight. In the case of a mixture containing 70 to 85% by weight of the former having highly active and amino groups having different activities, an appropriate thixotropic property appears in the mixture in the initial stage of curing after mixing with the main component,
It can be applied without dripping even on flat or inclined surfaces.

When the active hydrogen compound in the curing agent component is diethyltoluenediamine alone, the coating film obtained is stronger than when the active hydrogen compound other than diethyltoluenediamine is used in combination. Since the density of urea bonds in the hard segment is high and the degree of reaction completion is high, the mechanical strength retention at 60 to 80 ° C. for a long time can be greatly improved.

Therefore, it is suitable for use in a heat insulation method in which solar heat is accumulated, such as when a urethane coating is laminated on a heat-insulating rigid polyurethane foam or the like.

The additives mainly incorporated in the curing agent of the present invention are fillers, pigments, catalysts, various stabilizers, plasticizers, solvents and the like. Calcium carbonate, talc, clay,
Examples of the pigment include silica and carbon, and examples of the pigment include inorganic pigments such as chromium oxide and titanium oxide and organic pigments such as a phthalocyanine pigment.

Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, chlorinated paraffin, and petroleum-based plasticizers. Solvents include aromatic hydrocarbons such as toluene and xylene and n-heptane and n-heptane.
Examples include aliphatic hydrocarbons such as decane.

In addition, the above-mentioned organometallic catalyst may be added to accelerate the curing after the application. Further, stabilizers such as antioxidants, ultraviolet absorbers and dehydrating agents generally used in polyurethane resins can be blended.

The amount of the additives described above is not particularly limited, but is generally 40 to 80% by weight in the curing agent component.

As described above, the two-part waterproofing material composition according to the method of the present invention provides a coating film obtained because the isocyanate groups of the main chain of the polyurethane prepolymer sufficiently react with the active hydrogen groups in the curing agent. Has excellent mechanical properties.

[0031]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to only these Examples.

[Evaluation] <Content of unreacted polyisocyanate> The weight% of the peak of unreacted polyisocyanate in the prepolymer by GPC (gel permeation chromatography) analysis.

<Available time> The time from mixing the main agent and the curing agent until the coating operation becomes impossible. 5 ℃, 20 ℃
And measured at 35 ° C. <Curability> After coating, the time required until a person can walk on it. Measured at 5 ° C, 20 ° C and 35 ° C.

<Basic physical properties> Mechanical properties of the coating film as measured according to JIS A6021. In the table, E is elongation at break (unit:%), T _s is a tensile strength (unit / kg · c
m ^-2 ), and T _r is the tear strength (unit / kg · cm ^-1 ).

<Heat resistance> Mechanical properties after immersion in hot water at 60 ° C. for 7 days.

A main component of an isocyanate-terminated prepolymer was synthesized using the following polyoxyalkylene polyol and tolylene diisocyanate. Polyol A: a polyoxypropylene diol having a molecular weight of 2,000. Polyol B: polyoxypropylene triol having a molecular weight of 3,000.

Example 1 (Synthesis of Main Agent) 800 g of polyol A and polyol B2
157 g of a tolylene diisocyanate having a 2,4-isomer content of 80% by weight (NCO / OH equivalent ratio = 1.
8), and triethylamine as a catalyst was added in 2.
3 g was added, and the reaction was carried out at 80 ° C. for 3 hours in a reaction vessel.
Unreacted polyisocyanate content 0.12% by weight, free isocyanate content 2.88% by weight, viscosity 11,50
A polyurethane prepolymer of 0 cP / 20 ° C. was obtained.

(Preparation of a curing agent) 63.3 g of 4,4'-methylene-bis (2-chloroaniline) and 147.7 g of polyol A, which were previously heated and melted, were charged into a kneader.
Further, 600 g of calcium carbonate, 50 g of titanium oxide, 89.0 g of dioctyl phthalate, 30 g of xylene, 10 g of carbon black, and 10 g of lead octoate (lead content 24% by weight) were charged and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Example 2 (Synthesis of Main Agent) 800 g of polyol A and polyol B2
To 174 g of tolylene diisocyanate having a 2,4-isomer content of 100% by weight (NCO / OH equivalent ratio =
2.0), and 0.023 g of dibutyltin dilaurate as a catalyst was added.
The reaction was carried out for an unreacted polyisocyanate content of 0.5 hours.
A polyurethane prepolymer having 15% by weight, a free isocyanate group content of 3.47% by weight, and a viscosity of 8,000 cP / 20 ° C. was obtained.

(Preparation of curing agent) 22.28 g of 4,4'-methylene-bis (2-chloroaniline) and 51.9 g of diethyltoluenediamine, which were previously heated and melted in a kneader.
8 g were further charged, and 600 g of calcium carbonate, 50 g of titanium oxide, 235.74 g of dioctyl phthalate, 30 g of xylene, and 10 g of carbon black were further charged and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Example 3 Synthesis of Main Agent The same prepolymer as in Example 2 was used as the main agent.

(Preparation of Curing Agent) 66.8 g of diethyltoluenediamine, 600 g of calcium carbonate, 50 g of titanium oxide, 243.2 g of dioctyl phthalate, 30 g of xylene, and 10 g of carbon black were charged into a kneader and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Example 4 (Synthesis of Main Agent) 800 g of polyol A and polyol B2
157 g of a tolylene diisocyanate having a 2,4-isomer content of 80% by weight (NCO / OH equivalent ratio = 1.
8), and the mixture was reacted in a reaction vessel at 100 ° C. for 4 hours to obtain an unreacted polyisocyanate content of 0.32% by weight.
Free isocyanate group content 2.90% by weight, viscosity 1
A polyurethane prepolymer of 0.500 cP / 20 ° C. was obtained.

(Preparation of curing agent) 63.7 g of 4,4'-methylene-bis (2-chloroaniline) and 148.7 g of polyol A, which were previously heated and melted, were charged into a kneader.
Further, 600 g of calcium carbonate, 50 g of titanium oxide, 87.6 g of dioctyl phthalate, 30 g of xylene, 10 g of carbon black, and 10 g of lead octoate (lead content 24% by weight) were charged and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Example 5 (Synthesis of Main Agent) 800 g of polyol A and polyol B2
161 g of a tolylene diisocyanate having a 2,4-isomer content of 100% by weight (NCO / OH equivalent ratio =
1.85) was added thereto, and the reaction was carried out at 100 ° C. for 4 hours in a reaction vessel. The unreacted polyisocyanate content was 0.55% by weight, the free isocyanate group content was 3.01% by weight, and the viscosity was 9,000 cP / 20 ° C. Was obtained.

(Preparation of curing agent) 19.33 g of 4,4'-methylene-bis (2-chloroaniline) previously heated and melted in a kneader, and 45.0 of diethyltoluenediamine.
9 g were further charged, and 600 g of calcium carbonate, 50 g of titanium oxide, 245.58 g of dioctyl phthalate, 30 g of xylene, and 10 g of carbon black were further charged and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Example 6 Synthesis of Main Agent The same prepolymer as in Example 5 was used as the main agent.

(Preparation of curing agent) Into a kneader were charged 57.9 g of diethyltoluenediamine, 600 g of calcium carbonate, 50 g of titanium oxide, 252.1 g of dioctyl phthalate, 30 g of xylene, and 10 g of carbon black, and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Comparative Example 1 Synthesis of Main Agent 800 g of polyol A and polyol B2
191 g of tolylene diisocyanate having a 2,4-isomer content of 80% by weight (NCO / OH equivalent ratio = 2.
2) was added, and the reaction was carried out at 80 ° C. for 4 hours in a reaction vessel without a catalyst. A polyurethane prepolymer at 20 ° C. was obtained.

(Preparation of a curing agent) 90.1 g of 4,4'-methylene-bis (2-chloroaniline) and 210.3 g of polyol A, which were previously heated and melted, were charged into a kneader.
Further, 600 g of calcium carbonate, 50 g of titanium oxide, 29.6 g of xylene, 10 g of carbon black, and 10 g of lead octoate (lead content 24% by weight) were charged and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Comparative Example 2 (Synthesis of Main Agent) 800 g of polyol A and polyol B2
To 174 g of tolylene diisocyanate having a 2,4-isomer content of 100% by weight (NCO / OH equivalent ratio =
2.0) was added thereto, and the mixture was reacted at 80 ° C. for 4 hours in a reaction vessel without a catalyst, and the unreacted polyisocyanate content was 2.8.
A polyurethane prepolymer having a content of 5% by weight, a content of free isocyanate groups of 3.53% by weight and a viscosity of 6,500 cP / 20 ° C. was obtained.

(Preparation of curing agent) 22.66 g of 4,4'-methylene-bis (2-chloroaniline) and 52.8 of diethyltoluenediamine, which were previously heated and melted in a kneader.
Then, 600 g of calcium carbonate, 50 g of titanium oxide, 234.47 g of dioctyl phthalate, 30 g of xylene, and 10 g of carbon black were charged and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

Comparative Example 3 (Synthesis of Main Agent) 800 g of polyol A and polyol B2
To 174 g of tolylene diisocyanate having a 2,4-isomer content of 100% by weight (NCO / OH equivalent ratio =
2.0) was added thereto, and the mixture was reacted at 80 ° C. for 4 hours in a reaction vessel without a catalyst, and the unreacted polyisocyanate content was 2.8.
A polyurethane prepolymer having a content of 5% by weight, a content of free isocyanate groups of 3.53% by weight and a viscosity of 6,500 cP / 20 ° C. was obtained.

(Preparation of Curing Agent) 68.0 g of diethyltoluenediamine, 600 g of calcium carbonate, 50 g of titanium oxide, 242 g of dioctyl phthalate, 30 g of xylene, and 10 g of carbon black were charged into a kneader and uniformly mixed.

The above base material / hardening agent is mixed at a 1/1 weight ratio (NCO
/ NH ₂ equivalent ratio = 1.1) and used as a waterproof material.

[0064]

[Table 1]

[0065]

The mechanical properties of the obtained coating film are excellent.

Claims (5)

[Claims] 1. A main component containing an isocyanate group-terminated polyurethane prepolymer obtained by reacting a polyol containing a polyoxyalkylene polyol as a main component with a polyisocyanate, and a curing agent component containing an active hydrogen compound. A two-part waterproofing composition, which is a cold-curable two-part waterproofing composition, wherein the content of unreacted polyisocyanate in the isocyanate group-terminated polyurethane prepolymer is 1% by weight or less. 2. The isocyanate group-terminated polyurethane prepolymer obtained by reacting a polyol containing a polyoxyalkylene polyol as a main component with a polyisocyanate in the presence of a catalyst. Composition. 3. The composition according to claim 2, wherein the catalyst is a tertiary amine and / or an organometallic catalyst. 4. An isocyanate group-terminated polyurethane prepolymer comprises a polyol having a polyoxyalkylene polyol as a main component and a polyisocyanate, and an NCO group / O
The composition according to claim 1, which is an isocyanate group-terminated polyurethane prepolymer obtained by reacting the equivalent ratio of H groups in a range of more than 1.5 and less than 2. 5. The composition according to claim 1, wherein at least one active hydrogen compound in the curing agent component is an amine compound having two or more primary or secondary amino groups. .