JPH06220152A - Polyurethane-based curable composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, comprising a specific isocyanate group-terminated polyurethane prepolymer as a curing component, capable of providing a low-modulus and high-elongation cured product, excellent in quick curability and operating efficiency and useful as a sealing material, a structural adhesive, a waterproofing material, etc. CONSTITUTION:The objective composition comprises an isocyanate group- terminated polyurethane prepolymer obtained by reacting (A) one or two or more polyoxyalkylene polyols having >=2.5 average number of hydroxyl groups, 5-80 hydroxyl value X (mg KOH/g) and <=0.04 total unsaturation degree Y (mequiv./g) or a polymer-dispersed polyol containing a polymer of a polymerizable unsaturated group-containing monomer alone or a mixture of the polymer-dispersed polyol with the polyoxyalkylene polyol in the polyoxyalkylene polyols with (B) an organic polyisocyanate containing tolylene diisocyanate in an amount of preferably 3-100wt.% (based on the organic polyisocyanate) as a curing component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition which is cured at room temperature and gives a cured product having a low modulus and a high elongation and which is suitable as a sealing material, a structural adhesive or a waterproof material and has excellent workability. It is a thing.

[0002]

2. Description of the Related Art Polyurethane prepolymers having an isocyanate group at the end are used alone in a one-pack composition which reacts with moisture in the air to cure.

These one-component curable compositions are widely used in the fields of construction materials such as sealing materials, waterproof materials and floor materials, and civil engineering materials. In recent years, with the diversification of architecture and civil engineering styles, there has been a demand for a faster-curing, higher workability (low-viscosity system), flexible, and higher elongation sealing material and waterproof material.

[0004]

In the polyurethane-based moisture-curable composition, it is necessary to suppress the residual free isocyanate group to a low level of 2.0% or less at the highest in order to achieve low foaming property and fast curing property. It was However, when the free isocyanate group is lowered, the viscosity of the prepolymer which is the curable composition is increased, and the workability is extremely deteriorated. That is, low foaming property, fast curing property and high workability (low viscosity composition) were incompatible.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to solve the above-mentioned problems, as a result of the following method, a polyurethane-based water molecule curing agent having fast curing, low foaming property and high workability is obtained. To find a sex composition.

The curable composition of the present invention is suitable as a sealing material or a waterproof material. The term "sealing material" as used herein refers to a sealing material in a broad sense including a sealing material generally used for construction and a sealing material having adhesiveness to fill between the structural materials of a building.

In the present invention, one or more of the following polyoxyalkylene polyols are used, or a polymer-dispersed polyol containing a polymer of a polymerizable unsaturated group-containing monomer in the following polyoxyalkylene polyol is used alone or the polymer is dispersed therein. A polyurethane-based curable composition comprising an isocyanate group-terminated polyurethane prepolymer obtained by reacting a mixture of a polyol and the following polyoxyalkylene polyol with an organic polyisocyanate containing tolylene diisocyanate as a curing component. Polyoxyalkylene polyol: average number of hydroxyl groups is 2.5 or more, hydroxyl value X (mgKOH / g) is 5 ≦ X ≦
80, a polyoxyalkylene polyol having a total degree of unsaturation Y (meq / g) of Y ≦ 0.04.

In the present invention, the number of hydroxyl groups is 2.5 or more, the hydroxyl value X (mgKOH / g) is 5 ≦ X ≦ 80, and the total degree of unsaturation Y (meq / g) is Y ≦ 0.04. The oxyalkylene polyol can be obtained by using diethyl zinc, iron chloride, metalloporphyrin, complex metal cyanide complex or the like as a catalyst. In the case of an ordinary alkali catalyst such as KOH, the degree of unsaturation is high, especially in a high molecular weight compound, and it is not suitable. Preferably, a double metal cyanide complex catalyst is used.

The use of complex metal cyanide complexes such as cobalt zinc cyanide-glyme as catalysts for preparing polyalkylene oxides is known. This complex metal cyanide complex catalyst is, for example, EP28314.
8, USP3278457, USP3278458, U
It is described in the specification of SP3278459.

The polyoxyalkylene polyol in the present invention is preferably one produced by reacting a monofunctional or more functional initiator with an alkylene oxide in the presence of the above catalyst. As the alkylene oxide to be reacted with the initiator, ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide and the like are preferable.

Examples of the initiator include a mono- or polyhydroxy compound, a mono- or polyamine compound, and a polyoxyalkylene mono- or polyol having a lower molecular weight than the desired product obtained by reacting these with a relatively small amount of alkylene oxide.

Preferred are mono- or polyalcohols, mono- or polyphenols, mono- or polyamines, and polyoxyalkylene polyols having a lower molecular weight than the target product obtained by reacting these with a relatively small amount of alkylene oxide.

Specifically, methanol, ethanol, propanol, butanol, ethylene glycol, dipropylene glycol, butanediol, glycerin, trimethylolpropane, pentaerythritol, dextrose, bisphenol A, bisphenol S, and propylene oxide are reacted with them. There is a polyoxypropylene polyol obtained by. Two or more kinds of these initiators can be used.

The number of hydroxyl groups is 2.5 or more, and the hydroxyl value is X (m
gKOH / g) is 5 ≦ X ≦ 80, and the total degree of unsaturation Y
The polyoxyalkylene polyol having (meq / g) of Y ≦ 0.04 preferably satisfies the following inequality when 32.5 ≦ X ≦ 80. Y ≦ 0.9 / (X-10) (1) Further, the polyoxyalkylene polyol is preferably 5 ≦.
It is preferable that X ≦ 60, and most preferable that 5 ≦ X ≦ 45.

There are two methods for producing a polymer-dispersed polyol using the above polyoxyalkylene polyol. One is a method of directly polymerizing a polymerizable unsaturated group-containing monomer in a polyoxyalkylene polyol to precipitate particles, and the other is a method of precipitating particles in a solvent in the presence of a grafting agent for stabilizing the particles. , A method of obtaining a stable dispersion by substituting a solvent for polyoxyalkylene polyol. In the present invention, either method can be used, but the former method is particularly preferable.

As the polymerizable unsaturated group-containing monomer, a monomer having one polymerizable double bond is usually used, but it is not limited thereto.

As specific monomers, acrylonitrile, styrene, acrylamide, acrylic acid ester, methacrylic acid ester, vinyl acetate and the like are preferable, but not limited to them, for example, α-methylstyrene, dimethylstyrene, halogenated compounds. Styrene derivatives such as styrene, olefins such as butadiene and isoprene, acrylic derivatives such as methacrylonitrile, butyl acrylate and benzyl methacrylate, vinyl halides such as vinyl chloride, unsaturated fatty acid esters such as maleic acid diesters and itaconic acid diesters, etc. Can be used.

These monomers can be used alone or in combination with other monomers to form a copolymer. The most preferred monomers are acrylonitrile alone, styrene alone, acrylonitrile and styrene, or a combination of acrylonitrile or other monomers based on styrene.

As the polymerization initiator, a polymerization initiator of the type that produces free radicals to initiate polymerization is usually used. Specifically, for example, azobisisobutyronitrile, benzoyl peroxide, diisopropyl peroxydicarbonate, acetyl peroxide, di-t-butyl peroxide, dicumyl peroxide, dilauryloyl peroxide, persulfate, etc. is there. Azobisisobutyronitrile is particularly preferable.

The polymerization reaction is carried out at a temperature above the decomposition temperature of the polymerization initiator, usually at 80 to 160 ° C. The amount of monomer used is
About 60% by weight or less, particularly 10 to 50% by weight, based on the total amount of all polyoxyalkylene polyols and monomers, is preferred. After the completion of the polymerization reaction, the obtained polymer-dispersed polyol can be used as it is as a raw material for the isocyanate group-terminated polyurethane prepolymer, but it may be subjected to post-treatment such as removal of impurities such as decomposition products of the polymerization initiator.

Although a polymer-dispersed polyol in which polymer particles are stably dispersed can be obtained by the above-mentioned production method, it may be difficult to obtain a stable dispersion depending on the monomer used. Further, in order to improve the dispersion stability of the particles, a stabilizer or a grafting agent having a double bond in the molecule can be used.

As the grafting agent, a high molecular weight polyol or monool obtained by reacting an alkylene oxide with an active hydrogen compound having a vinyl group, an allyl group, an isopropyl group or the like as an initiator, maleic anhydride with a polyol,
Itaconic anhydride, maleic acid, coumaric acid, acrylic acid,
After reacting an unsaturated carboxylic acid such as methacrylic acid or its hydrate, and optionally adding an alkylene oxide such as propylene oxide or ethylene oxide, a polymer polyol or monool, a polyol and a polyisocyanate, and 2-hydroxyethyl. Examples thereof include high molecular weight polyols or monools obtained by the reaction of unsaturated alcohols such as acrylate and butenediol, and reaction products of unsaturated epoxy compounds such as allyl glycidyl ether.

Further, it is desirable that the reaction product of the polyol and the modifier as described above has a hydroxyl group as a particle stabilizer or a grafting agent, but a compound having essentially no hydroxyl group is fully modified by the modification. As a particle stabilizer.

The amount of polymer particles in the polymer-dispersed polyol is not particularly limited, but is preferably 50% by weight or less, and particularly preferably 40% by weight or less. The lower limit of the amount is 2
%, Especially 5% by weight is preferred.

When the polymer-dispersed polyol is used as a raw material for a polyurethane prepolymer, it can be diluted with a diluent before use. At this time, the diluent is the above polyoxyalkylene polyol in the present invention.

The isocyanate group-terminated polyurethane prepolymer in the present invention is obtained by reacting the above-mentioned polymer-dispersed polyol alone or a mixture of the polymer-dispersed polyol and the above-mentioned polyoxyalkylene polyol with various organic polyisocyanates under conditions of excess polyisocyanate compound. Obtained by

As the organic polyisocyanate, tolylene diisocyanate (hereinafter referred to as TDI) alone or in a composition containing TDI, is obtained by modifying an aromatic or aliphatic polyisocyanate having two or more isocyanate groups and modifying them. Mixtures with modified polyisocyanates can be used.

TDI has 2,4- and 2,6-isomers, and TDI-100 (2,4-TDI 100 is used depending on the mixing ratio of 2,4-TDI and 2,6-TDI.
%), TDI-80 (2,4-TDI / 2,6-TDI
= 80/20), TDI-65 (2,4-TDI / 2,
6-TDI = 65/35) is generally used, but the TDI used in the present invention is not limited to these.

Specific examples of the isocyanate other than TDI include diphenylmethane diisocyanate (MD
I) is often used, but other specific examples include polymethylene polyphenyl isocyanate (commonly known as crude MDI) and xylylene diisocyanate (X).
DI), polyisocyanates such as isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI), and their prepolymer modified products, nurate modified products, urea modified products, carbodiimide modified products and the like. The content of TDI in the organic polyisocyanate is 3
-100% by weight is preferred. Particularly, 10 to 50% by weight is preferable.

The polyurethane-based curable composition of the present invention is
A water-curable one-pack type curable composition containing the polyurethane prepolymer alone as a curing component, but containing a compound that blocks a curing acceleration catalyst in the curing reaction, such as a mineral acid of an amine or a carbonate. Good.

If a stabilizer and deterioration preventive agent are used in combination,
Further, excellent weather resistance and heat resistance can be imparted. The composition of the present invention may further contain a reinforcing agent, a filler, a plasticizer, a pigment, an anti-sagging agent and the like, if necessary.

Carbon black, fine powder silica, etc. are used as the reinforcing agent, and calcium carbonate, talc,
Clay, silica, etc., plasticizers such as dioctyl phthalate, dibutyl phthalate, dioctyl adipate, chlorinated paraffin and petroleum plasticizers, and pigments include iron oxide, chromium oxide, inorganic pigments such as titanium oxide and phthalocyanine blue, phthalocyanine. Examples of organic pigments such as green include organic acid-treated calcium carbonate, hydrogenated castor oil, aluminum stearate, calcium stearate, zinc stearate, and fine powder silica as an anti-sagging agent.

The curable composition of the present invention comprises a sealing material,
Can be used as a waterproof material. Particularly, it is suitable for applications in which the adhesiveness of the cured product itself and sufficient strength are required.

[0034]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

(Polyol) A: A molecular weight of 100 obtained by adding propylene oxide to glycerin and then adding ethylene oxide.
00, hydroxyl value 17, ethylene oxide content 10% by weight, total unsaturation degree 0.032, polyoxyalkylene triol. B: A polymer-dispersed polyol obtained by charging acrylonitrile in 20% by weight of the total polyol in A, adding 0.5% by weight of azobisisobutyronitrile as an initiator, and polymerizing at 110 ° C.

C: Polyoxyalkylene triol having a molecular weight of 7,000, a hydroxyl value of 24, an ethylene oxide content of 12% by weight, and a total degree of unsaturation of 0.025, obtained by adding propylene oxide to glycerin and then adding ethylene oxide.

D: Polyoxyalkylene diol having a molecular weight of 4000, a hydroxyl value of 28, an ethylene oxide content of 15% by weight, and a total degree of unsaturation of 0.018, obtained by adding propylene oxide to propylene glycol and then adding ethylene oxide.

E: Polyoxyalkylene triol having a molecular weight of 7,000, a hydroxyl value of 24, an ethylene oxide content of 12% by weight, and a total degree of unsaturation of 0.11, obtained by adding propylene oxide to glycerin and then adding ethylene oxide.

F: Polyoxyalkylene tetraol having a molecular weight of 13,000 obtained by adding propylene oxide to pentaerythritol, and then adding ethylene oxide, a hydroxyl value of 17, a content of ethylene oxide of 10% by weight, and a total degree of unsaturation of 0.020. .

MDI / TDI-shown in Table 1 is MDI / TDI-80, a mixture of polyols having the average number of hydroxyl groups (f) shown in Table 1 mixed with the types shown in Table 1 and weight ratios.
The mixture mixed at a ratio of 80% by weight was charged into a reaction vessel and the reaction was carried out at 80 ° C., and the viscosity shown in Table 1 (unit: c
A polyurethane prepolymer having a ps / 25 ° C.) and an NCO content (unit:%) was obtained. This prepolymer is at 20 ° C.
The tackiness of the sample left to stand for 1 day at 5% RH was evaluated by touch with a finger. The results are shown in Table 1. However, the evaluation is as follows. ◯: Completely cured and no stickiness. △ ・
..Curing is progressing, but it is sticky. X: Poor curing.

Next, the same prepolymer was molded into a sheet having a thickness of 0.50 mm and completely cured by moisture. Sheet physical properties tensile strength T _B (unit: kg / cm ^2), elongation at break E _B (unit:%), 100% modulus M ₁₀₀ (unit: kg / c
m ² ) was investigated. The evaluation results are shown in Table 1.

[0042]

[Table 1]

[0043]

The polyurethane-based curable composition of the present invention is a composition which is cured to give a cured product suitable for a sealing material or a waterproof material. The present invention provides a composition having high workability, which has not been obtained in the past but has a rapid curing property and a low foaming property.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // C09K 3/18 101 8318-4H

Claims (5)

[Claims] 1. The following polyoxyalkylene polyol 1
Or two or more, or a polymer-dispersed polyol containing a polymer of a polymerizable unsaturated group-containing monomer in the following polyoxyalkylene polyol alone or a mixture of the polymer-dispersed polyol and the following polyoxyalkylene polyol, and tolylene diisocyanate A polyurethane-based curable composition comprising an isocyanate group-terminated polyurethane prepolymer obtained by reacting an organic polyisocyanate containing the above as a curing component. Polyoxyalkylene polyol: average number of hydroxyl groups is 2.5 or more, hydroxyl value X (mgKOH / g) is 5 ≦ X ≦
80, a polyoxyalkylene polyol having a total degree of unsaturation Y (meq / g) of Y ≦ 0.04. 2. The polyurethane curable composition according to claim 1, wherein the organic polyisocyanate contains 3 to 100% by weight of tolylene diisocyanate. 3. The hydroxyl value X (mgKOH / g) is 5 ≦ X ≦.
The polyurethane-based curable composition according to claim 1, which is 60. 4. The polyurethane curable composition according to claim 1, wherein the polyurethane curable composition is moisture curable. 5. A sealing material, a structural adhesive, or a waterproof material obtained by curing the polyurethane curable composition according to any one of claims 1 to 4.