JPH039942B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a curable urethane composition with excellent heat resistance suitable for use as a sealant, surface waterproofing material, paving material, or similar material. More specifically, a curable urethane composition containing a urethane prepolymer having an isocyanate group at the molecular end, an active hydrogen-containing compound, an organic lead compound as a urethanization catalyst, and, if necessary, a reinforcing material, a filler, a diluent, etc. When using the product as a sealing material, surface waterproofing material, or paving material, by blending a phosphite compound into this composition,
This relates to significantly improving weather resistance and heat resistance. The two-part curable urethane composition cures at room temperature,
The cured product is rich in strength, elongation, elasticity, adhesiveness, and water resistance, so it is widely used in applications such as sealing materials, waterproofing materials, and paving materials. Such curable urethane compositions have a urethane prepolymer containing an isocyanate group at the molecular end as a main ingredient, and active hydrogen compounds such as polyether polyol, polyhydric alcohol, and methylenebis-o-chloroaniline (hereinafter abbreviated as MOCA).
etc. and an organic lead compound as a urethanization catalyst is used as a hardening agent.The main agent and hardening agent are kneaded at the construction site and sealed in joints as a sealant, waterproofing material, etc. It is used as a paving material by applying it to the base. Generally, cured products are relatively flexible for these uses;
Since properties such as high elongation at break are required, polyether polyols are often used as active hydrogen compounds that react with the isocyanate groups of the main ingredient to meet these requirements. Usually this isocyanate group and active hydrogen compound,
In particular, organolead compounds are generally used as catalysts to promote urethanization in the reaction with polyether polyols, and the curing time of these two-component urethanes can be adjusted by adjusting the amount of this organolead compound added, depending on the construction conditions. It is tailored to fit. However, although this organic lead compound has the advantage of being able to adjust the curing time of two-component urethane by adjusting the amount added, on the other hand, it significantly reduces the heat resistance and durability after curing, and if the amount added increases, There is a drawback that the degree of decrease becomes greater as the number increases. From the viewpoint of workability, it is desirable to increase the amount of organolead compound to speed up curing, but this will significantly reduce performance after curing, especially heat resistance, so there is a limit to the amount of organolead compound added. Up until now, either the workability has been neglected, or the performance has been neglected. In addition, for rooftop waterproofing and sealing of structures, the exposed parts are heated to around 80°C by the radiant heat of the sun, and the previously used curable urethane compositions can maintain their physical properties for a long period of time. I couldn't do it. As a result of intensive research to eliminate these drawbacks, the present inventors have developed a catalyst for promoting the reaction of an organic lead compound with a urethane prepolymer (hereinafter simply referred to as prepolymer) having an isocyanate group at the molecular end and an active hydrogen compound. The inventors have now invented a curable non-foaming urethane composition with excellent heat resistance, which is characterized in that it contains at least one of the following phosphite esters. Phosphite ester represented by the general formula (RO) ₂ P-OH or (RO) ₂ PH=O (where R is an alkyl group or an aryl group which may be substituted with an alkyl group, and has 1 carbon number) 25 to 25) The urethane composition of the present invention is a two-component type, and is usually treated as a base agent and a curing agent separately, and the two are mixed at the construction site to form the urethane composition of the present invention. becomes. The main prepolymer used in the present invention is 1
A polyisocyanate containing two or more NCO groups in the molecule is reacted with a polyether polyol or polyester polyol having two or more active hydrogen groups per molecule in a proportion such that the isocyanate groups are in excess. It can be obtained by As the polyether polyols mentioned here, any polyether polyols conventionally used in the production of polyurethane can be used, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Examples include polyol monomers such as 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol bisphenol A, trimethylolethane, trimethylolpropane, glycerin, and sorbitol; , these monomers or amine monomers such as ethylenediamine, urea, monomethyldiethanolamine, and monoethyldiethanolamine are polymerized with alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and styrene oxide, or Any polyether polyol consisting of a copolymer or a mixture of these polymers can be used. Furthermore, condensates of polybasic acids and polyhydric alcohols are used as polyester polyols, such as maleic acid, fumaric acid, adipic acid,
Obtained by the reaction of phthalic acid, etc. alone or in mixtures with ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, etc. alone or in mixtures. Examples include polyester polyols having a terminal OH group. Preferably, polyether polyols are used, which are liquid at room temperature and easy to handle. As the organic polyisocyanate, any organic polyisocyanate used in the production of polyurethane can be used, such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4/2,6=65/35 (wt) Tolylene diisocyanate, 2,4/2,6 = 80/20 (wt) Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, 1,5
-naphthalene diisocyanate, metaxylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate, crude tolylene diisocyanate, polymethylene polyphenyl isocyanate, and the like. These can be used alone or as a mixture. Further, prepolymers containing terminal isocyanate groups obtained by the reaction of the polyether polyols or polyester polyols with organic polyisocyanates may be used alone or in mixtures thereof. The curing agent of the present invention is composed of an active hydrogen-containing compound and an organic lead compound. Polyoxyethylene polyol, polyoxypropylene polyol, or polyoxyethylene propylene copolymer polyol with an average functional group number of 2 to 3, which indicates the number of hydroxyl groups in the molecule, has a molecular weight of 400.
Those having a molecular weight of 1,000 to 10,000, preferably 1,000 to 8,000 are used alone or in combination. The NCO/H ⁺ ratio in the reaction between the isocyanate groups of the prepolymer and the active hydrogen compound in the curing agent is 1.6~
The equivalent ratio is 0.7. The organic lead compound as a reaction promoting catalyst includes a substance that promotes general urethanization reactions, such as lead salts of organic acids such as lead acetate, lead caproate, lead octylate, lead naphthenate, etc., and preferably lead salts of organic acids such as lead octylate, lead naphthenate, etc. Lead and lead naphthenate are used.
These may be used alone or in combination, and the amount added is 1 to 15 millimoles as an organic lead compound per 100 parts by weight of the prepolymer. The phosphite of the present invention has the general formula (RO) ₂ P
-OH or (RO ₅ )PH=O, but R
The same or different carbon atoms having 1 to 25 carbon atoms can be used. However, as the number of carbon atoms decreases, the boiling point of R decreases, making it easy to volatilize.On the other hand, as the number of carbon atoms increases, the melting point of R increases, making it difficult to be compatible with urethane resins. , R preferably has 6 to 18 carbon atoms. Examples of the phosphites of the present invention include diphenylhydrogen phosphite, di-
2-ethylhexylhydrogen phosphite,
Examples include phosphite esters obtained by the reaction of phosphorus trichloride and alcohol such as di-2-ethylhexyl hydrogen phosphite, dilauryl hydrogen phosphite, and dioleyl hydrogen phosphite. Dialkyl phosphite esters that are difficult to decompose are desirable, and these compounds may be used alone or in combination. Furthermore, among the phosphite esters, the general formula
Even if a monoalkyl (or monoaryl) phosphite of the general formula RO-P(OH) ₂ and a trialkyl (or triall) phosphite of the general formula (RO) ₃ P are used, the present invention will not fail. It does not exhibit the same effect as is produced when using zinc phosphate esters of the general formula (RO) ₂ P-OH or (RO) ₂ PH=O. The phosphite compound of the present invention can be added to the prepolymer in advance or at the stage of mixing the base agent and the curing agent, but it is preferable to add it to the prepolymer in advance. The amount of the phosphite compound of the present invention added is 0.2 to 8 mol, preferably 0.5 to 8 mol, per 1 mol of the organic lead compound.
3 moles is suitable. Furthermore, if necessary, the urethane composition may contain reinforcing agents, fillers, diluents, and the like. These compounding agents may be included in the curing agent in advance, and these compounding agents have a reinforcing effect that improves the physical strength of the resulting cured urethane product and an economical effect that reduces the price of the curable urethane composition. This brings about benefits such as improved workability by making curing easier. Examples of reinforcing agents having such an effect include carbon black and finely powdered silica, and examples of fillers include calcium carbonate, talc, clay, silica, and titanium oxide. Furthermore, if necessary, a plasticizer such as dioctyl phthalate, dibutyl phthalate, dioctyl adipate, or toluene or xylene may be added as a diluent to reduce the viscosity of the urethane composition, especially the curing agent, and improve workability at the construction site. , turpentine, or other solvents may be blended. In addition, conventionally used inorganic or organic pigments may be added in order to obtain a beautiful finished surface by coloring. Mixing of various components can be easily carried out by conventional mixing means. After adjustment, this urethane composition has a
It hardens (gels) in about 300 minutes, but preferably hardens in 40 to 120 minutes. According to the urethane composition of the present invention, the weather resistance and heat resistance of the cured film are significantly improved, and the paving, waterproofing, or sealing effect is maintained for a long period of time, and it can be used as a sealing material, surface waterproofing material, and surface paving material. or can be suitably used as analogs thereof. EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Examples 1-12 Polyoxypropylene glycol with a molecular weight of 2000
2,4/2,6 in a mixture of 500 parts by weight and 500 parts by weight of polyoxypropylene triol with a molecular weight of 3000.
= Tolylene diisocyanate with an isomer ratio of 80/20
174 parts by weight was added, and the reaction was continued at 80° C. for 6 hours in a reaction vessel. The viscosity of the obtained prepolymer is 25
% free isocyanate was 3.5% at 9200 cps. This was used as the main ingredient of curable urethane. On the other hand, the curing agent was made by kneading a mixture of 100 parts by weight of polyoxypropylene glycol with a molecular weight of 3000, 20 parts by weight of SRF carbon, 65 parts by weight of calcium carbonate with a particle size of 200 mesh, and 15 parts by weight of dioctyl phthalate using three rolls to form a homogeneous paste. A dispersion was prepared. When blending this main agent and curing agent, a turpentine solution of lead octylate (lead content 24%) and dilauryl hydrogen phosphite (trade name "Chelex H-12" Sakai Chelex H-
8 (manufactured by Sakai Chemical Industry Co., Ltd.) in the amounts shown in Table 1, the mixture was mixed until sufficiently uniform, and the mixture was coated on release paper to a thickness of 2 mm to prepare a cured product. After leaving this sheet-shaped cured urethane product in a room at 20°C and 65% humidity for 7 days, test pieces were prepared using a tensile No. 3 dumbbell and a tear B-type dumbbell according to JIS K-6301 (vulcanized rubber physical testing method). Three pieces were taken out and their physical properties under normal conditions and after a heat resistance test in which they were placed in a soaking dryer at 100°C for 5 days were examined. The test results obtained are shown in Table-1. Comparative Examples 1 and 2 When blending the main ingredient and curing agent obtained in Example 1, a turpentine solution of lead octylate as a reaction catalyst was added to the curing agent in advance in the amount shown in Table 1, and the following Example 1 was prepared. In the same manner as above, cured products were prepared and various tests were conducted, and the results are shown in Table 1. Examples 13 to 24 The prepolymer obtained in Example 1 was used as the main ingredient, and the curing agent was prepared by dissolving 5 parts by weight of MOCA in 50 parts by weight of polyoxypropylene glycol with a molecular weight of 3000 by heating it to 110°C, and then dissolving it in a particle size of 200 mesh. A mixture of 40 parts by weight of calcium carbonate and 5 parts by weight of red iron oxide was kneaded using three rolls to prepare a homogeneous paste-like dispersion. In blending the main ingredient and the curing agent, evaluation was made in the same manner as in Example 1 by adding lead octylate turpentine solutions Chelex H-12 and Chelex H-8 in the amounts shown in Table 2. The test results obtained are shown in Table-2. Comparative Examples 3-4, 5-16, 17-22 When blending the main ingredient and curing agent obtained in Example 13, a turpentine solution of lead octylate was prepared as shown in Table 2 in the same manner as in Example 1. The cured product was evaluated, and the test results obtained are shown in Table 2. Comparative Examples 5 to 5 were conducted in the same manner as in Example 1 except that other phosphorus compounds shown in Table 3 were used in place of the phosphite represented by the formula of the present invention.
The results are shown in Table 3. Both had poor heat resistance and softened too much, making it impossible to measure their physical properties. Further, test results were conducted in the same manner as in Example 1 using dibutyltin dilaurate instead of the organic lead compound, and the results are shown in Table 4 as Comparative Examples 17 to 22.
In both cases, the cured products exhibited a foaming phenomenon, and the normal physical properties were also significantly worse than in the examples.
It had poor performance, failing to pass the standards for tensile strength and elongation specified in JISA6021 (roof waterproof coating materials).

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[Table] As shown in Tables 1 and 2, the curable urethane composition containing the phosphite ester of the present invention has high tensile strength, tear strength, and elongation even after the heat resistance test. It is clear that it retains its value and has very good heat resistance.

Claims (1)

[Claims] 1 (A) Urethane polymer having an isocyanate group at the end of the molecule, (B) Active hydrogen-containing compound (C) Organic lead compound (D) General formula (Ro) ₂ P-OH or (Ro) ₂ PH=O (However, R is an alkyl group or an aryl group which may be substituted with an alkyl group, and has 1 to 1 carbon atoms.
Say things up to 25. ) A curable non-foaming urethane composition having excellent heat resistance and comprising at least one phosphite ester represented by: