JP2000007910A - One package type moisture-curable urethane resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having excellent storage stability and freely adjustable curability by compounding a urethane prepolymer and a silyl phosphate ester in a specific amount based on components other than the silyl phosphate ester. SOLUTION: A resin composition comprises a urethane prepolymer and 0.001-30 pts.wt. of a silyl phosphate ester based on 100 pts.wt. of components other than the silyl phosphate ester. If required, a plasticizer, a filler, an antioxidant, an ultraviolet absorbent, a colorant, a solvent and the like can further be compounded. The silyl phosphate is a compound represented by the formula such as trimethylsilyl di(2-ethylhexyl)phosphate ester or the like. The urethane prepolymer is obtained by mixing one equivalent of a polyol compound such as a polyetherpolyol, polyesterpolyol or the like with 1.2-5 equivalents of a polyisocyanate compound and heating them to allow react. In the formula, R is an alkyl; X is an organic group optionally containing a heteroatom; and (n) is an integer of 1-3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a one-pack type moisture-curable urethane resin composition. More specifically, the present invention relates to a one-pack type moisture-curable urethane resin composition capable of freely adjusting curability while maintaining storage stability.

[0002]

2. Description of the Related Art One-part moisture-curable urethane resin compositions are widely used as sealing agents, waterproofing agents, jointing agents, adhesives, paints, and the like. Such one-component moisture-curable urethane resin compositions are required to have different curability depending on the purpose of use, method of use, and season of use. However, in general, it has been difficult to increase the curability of a one-component moisture-curable urethane resin composition without impairing the storage stability.
For example, when it is desired to cure a one-component moisture-curable urethane resin composition in a short time, an organometallic compound and an amine compound are added as a curing catalyst. The moisture-curable urethane resin composition is
Although the curing time is shortened, the storage stability is reduced. In order to solve the problem that the storage stability of such a curing catalyst is reduced, the invention of adding oxazolidine or enamine as a latent curing agent, or further adding an acidic compound having a specific acidity thereto, is a special feature. It is disclosed in Japanese Unexamined Patent Publication No. Hei 9-278857 and Japanese Unexamined Patent Publication No. Hei 7-289989. High curability can be obtained by adding these latent curing agents. However, since these compounds are amines, there is a problem that the storage stability also decreases when used over a certain amount. Also,
The addition of the acidic compound activates these latent hardeners during storage and also reduces storage stability.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a one-pack type moisture-curable urethane resin composition which has good storage stability and whose curability can be freely adjusted.

[0004]

That is, the present invention comprises a urethane prepolymer and a silyl phosphate ester,
For 100 parts by weight of components other than silyl phosphate,
Provided is a one-part moisture-curable urethane resin composition containing 0.001 to 30 parts by weight of a silyl phosphate.

It is preferable that the silyl phosphate is a compound represented by the formula (1).

Embedded image (R is an alkyl group, X is an organic group optionally having a hetero atom, and n represents an integer of 1 to 3.)

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The one-pack moisture-curable urethane resin composition of the present invention (hereinafter, referred to as the composition of the present invention) is a urethane composition containing a urethane prepolymer and the silyl phosphate represented by the above formula (1). is there.

The urethane prepolymer blended in the composition of the present invention comprises a polyol compound and an excess of a polyisocyanate compound (ie, an excess of NCO groups with respect to OH groups), as in a normal one-pack type polyurethane resin composition. Is a reaction product obtained by reacting
It contains ５5% by weight of isocyanate groups at the molecular terminals.

As the polyisocyanate compound for producing such a urethane prepolymer, various compounds used in the production of ordinary one-pack type polyurethane resin compositions can be used. Specifically, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4
4'-diphenylmethane diisocyanate, 2,4'-
Aromatic polyisocyanates such as diphenylmethane diisocyanate, p-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate;
Preferred examples include alicyclic polyisocyanates such as isophorone diisocyanate; aryl aliphatic polyisocyanates such as xylylene diisocyanate; carbodiimide-modified or isocyanurate-modified polyisocyanates of the above polyisocyanates. These may be used alone or in combination of two or more.

As the polyol compound for producing the urethane prepolymer, polyether polyols, polyester polyols, other polyols, and mixed polyols thereof can be used as in the case of the usual one-pack type polyurethane resin composition. .

Examples of the polyether polyol include one or two or more compounds having two or more active hydrogens in one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide and tetrahydrofuran. A product obtained by addition polymerization of the above can be mentioned. Examples of the compound having two or more active hydrogens include polyhydric alcohols, amines, and alkanolamines. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, 1,1,1-trimethylolpropane, 1,2,5-hexanetriol, 1,3-butanediol, 1,4- Butanediol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxyphenylmethane, pentaerythritol, etc .; amines include ethylenediamine, propanolamine, etc .; alkanolamines include ethanolamine, propanolamine, etc. ;

Further, as the polyester polyol,
One or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, 1,1,1-trimethylolpropane, or other low molecular weight polyols, and glutaric acid, adipic acid , Pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid, dimer acid, or a condensation polymer with one or more of low molecular carboxylic acids and oligomeric acids; propionyl lactone, valerolactone, etc. Ring polymer; and the like.

Further, other polyols include polycarbonate polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, acrylic polyols and the like, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol, hexanediol and the like. Of low molecular weight polyols.

When a urethane prepolymer having an isocyanate group at a molecular end produced by using such a polyol compound and an excess of a polyisocyanate compound is obtained, the mixing ratio of the polyol compound and the polyisocyanate compound is not limited to the polyol. 1 equivalent of compound (OH equivalent)
Per equivalent of polyisocyanate compound 1.2 to 5 equivalents (N
CO equivalent), and more preferably 1.5 to 3 equivalents. Further, in the production of this urethane prepolymer, as in the case of a normal urethane prepolymer, both compounds are mixed at a predetermined quantitative ratio, usually at 30 to 120 ° C., preferably 50 to 100 ° C.
It is performed by heating and stirring at ℃.

The silyl phosphate ester contained in the composition of the present invention is a compound having a chemical structure represented by the following formula (1), regardless of a monomer, polymer, low molecular weight, or high molecular weight.

Embedded image In the formula, R represents an alkyl group such as a methyl group or an ethyl group;
Is an organic group optionally having a hetero atom, for example, an alkyl group such as a methyl group or an ethyl group; a methoxy group, an ethoxy group, a butoxy group, a hexaoxy group, a 2-ethylhexaoxy group, an octadecyloxy group (CH ₃ (CH ₂ ) ₁₇ O
An alkoxy group such as-); a trimethylsilyloxy group or the like, and n represents an integer of 1 to 3. When n is 2 or more, R may be the same or different substituents. When 3-n is 2 or more, X may be the same substituent or different substituents. As specific examples, the following compounds can be shown.

Embedded image In the formula, R ¹ represents a methyl group, an ethyl group, a butyl group, a hexyl group, a 2-ethylhexyl group, a stearyl group, an oleyl group, or the like. m represents an integer of 1 or more.

The silyl phosphate represented by the formula (1) can be obtained, for example, by reacting the corresponding phosphoric acid with a trialkylchlorosilane or an alkylsilazane.

The composition of the present invention contains a silyl phosphate represented by the formula (1). The silyl phosphate is hydrolyzed by moisture in the air to generate phosphoric acid. Phosphoric acid promotes hydrolysis of isocyanate groups, and when an oxazolidine-based curing agent is added to the composition of the present invention, the hydrolysis is also promoted. The curability can be adjusted by increasing or decreasing the content of the silyl phosphate contained in the composition of the present invention by these reactions. For example, as can be seen from a comparison between Example 1 and a standard example, which will be described later, trimethylsilyl ester of di (2-ethylhexyl) phosphate, which is one example of the above silyl phosphate, is converted to a total of 100 components other than the silyl phosphate. The composition of the present invention containing 0.01 parts by weight with respect to parts by weight can shorten the curing time (tack-free time) compared to the urethane prepolymer containing no silyl phosphate at all, as shown in the standard example. it can. On the other hand, as shown in Example 2 and Example 4 described below, a small amount of the silyl phosphate was added to 100 parts by weight of the components other than the silyl phosphate.
For example, 0.01 parts by weight and a large amount, for example, 0.1 parts by weight.
In the case of 1 part by weight, the curing time can be changed about 7 times. As described above, by controlling the content of the silyl phosphate, the curability can be freely adjusted, and it is possible to respond to the different curability requirements depending on the purpose of use, method of use, and season of use. On the other hand, since the silyl phosphate is neutral during storage of the composition of the present invention, it does not adversely affect storage stability. Therefore,
The curability of the composition of the present invention can be controlled without impairing the storage stability and thixotropic properties of the composition of the present invention.

The content of the silyl phosphate in the composition of the present invention is 0.001 to 30 parts by weight, preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the components other than the silyl phosphate. 005 to 20 parts by weight. Within this range, the curability can be increased without impairing the storage stability. If the amount is less than 0.001 part by weight, the curing speed cannot be increased. If it exceeds 30 parts by weight, the raw material cost for producing the composition of the present invention becomes high, which is economically disadvantageous.

The composition of the present invention may further comprise, if necessary, other additives such as a solvent such as toluene, xylene, and mineral spirits, in addition to the above essential components, as long as the object of the present invention is not impaired. Plasticizers such as phthalate, diundecyl phthalate, dibutyl phthalate, dinonyl phthalate, diisodecyl adipate, dioctyl adipate; calcium carbonate, carbon black,
Fillers such as talc, clay, silica, titanium oxide;
Colorants such as pigments and dyes; antioxidants; ultraviolet absorbers; and the like may be added. Further, a silyl ester of a higher fatty acid or the like may be used as a dehydrating agent. Since the silyl ester of a higher fatty acid is more easily hydrolyzed to the carboxylic acid and silanol than the isocyanate group of the urethane prepolymer, the curing reaction of the urethane prepolymer due to the moisture adsorbed on the fillers and the like incorporated in the urethane composition. Since it can be prevented, it can contribute to improvement of storage stability. Further, an oxazolidine-based curing agent may be added to such an extent that storage stability is not impaired. Oxazolidine-based curing agents, for example, a reaction product of a hydroxyl group-containing oxazolidine and a polyisocyanate, or a partially blocked isocyanate group of a urethane prepolymer with the oxazolidine does not react with the isocyanate group, but the oxazolidine group is present in the air. The ring is opened by the water to form a hydroxyl group and an imino group, and reacts with the isocyanate group to cause a crosslinking reaction to promote curability.

The method for producing the composition of the present invention is not particularly limited, and the composition may be produced in the same manner as in a usual one-pack type urethane composition. For example, a method in which each component is sufficiently kneaded under reduced pressure and uniformly dispersed is exemplified.

The composition of the present invention has excellent storage stability by adopting the above constitution. In addition, the curability of the composition of the present invention can be freely adjusted by adjusting the amount of the silyl phosphate represented by the formula (1) blended in the composition of the present invention within a predetermined range. Can do things. The composition of the present invention has thixotropy by containing the silyl phosphate, and the curability can be freely controlled without lowering the thixotropy and storage stability. Therefore, the composition of the present invention can be suitably used as a sealing agent, a waterproofing agent, a jointing agent, an adhesive, a paint, and the like. It may be a composition having a weight.

[0021]

The present invention will be specifically described below with reference to examples. Synthesis Example of Urethane Prepolymer 960 g of dried polypropylene diol having an average molecular weight of 3000 (Exenol 3020 manufactured by Asahi Glass Co., Ltd.), 1000 g of polypropylene triol having an average molecular weight of 5000 (Preminol 3005 manufactured by Asahi Glass Co., Ltd.), and 665 g of dioctyl phthalate to 255.5 g of diphenylmethane diisocyanate At 80 ° C. in the presence of a catalyst in a nitrogen stream
For 18 hours to obtain a prepolymer having an NCO content of 1.1% by weight.

Synthesis Example of Silyl Phosphate ( LB58-OSi) Di (2-ethylhexyl) phosphate (LB58) 1
30 g of hexamethyldisilazane was dropped into 00 g, and reacted at room temperature for 30 minutes and at 60 ° C. for 1 hour. Ammonia and excess hexamethyldisilazane were removed under reduced pressure to obtain the target compound. The obtained compound is shown in Table 1 below as LB
Write 58-OSi. In addition, the structure of the obtained compound was confirmed by ¹ HNMR.

Synthesis of Sealant Composition 130 g of the above urethane prepolymer was added at 110 ° C. for 24 hours.
100 g of calcium carbonate (Sealed 200, Maruo Calcium Co., Ltd.) dried for 10 hours, 10 g of titanium oxide (R810, Ishihara Sangyo), 5 g of xylene, and 3 g of poly (methyl stearoxy siloxane) are mixed and uniformly dispersed with a high-viscosity mixing mixer. Then, a sealant composition was obtained.

(Examples 1 to 8, Comparative Example 1) A urethane resin composition was prepared according to the formulation shown in Table 1 below, and the viscosity, thixotropic property, and curability of the obtained composition were measured by the following methods. evaluated. In the table, the unit of the compound is part by weight. Test Method 1) Viscosity (Storage Stability) After storing at 20 ° C. for 1 day and at 70 ° C. for 1 day, the viscosity was measured using a B-type viscometer and evaluated as the initial viscosity and the viscosity after storage, respectively. 2) Thixo Index TI (Thixotropic) After storing at 20 ° C. for 1 day and at 70 ° C. for 1 day, the viscosity ratio measured at 1 rpm and 2 rpm using a B-type viscometer was calculated as the thixo index. , Initial T
I, evaluated as TI after storage. The higher this value, the more
It shows that thixotropic is high. 3) Tack free time (curability) Immediately after adjusting the compositions obtained in Examples and Comparative Examples,
After storage for one day, the tack-free time was measured according to the method described in JIS A 5758. Table 1 shows the results.

[0025]

[Table 1]

<Each component in the table> LB58-OSi: Trimethylsilyl ester of di (2-ethylhexyl) phosphate DBP-OSi: Trimethylsilyl ester of dibutyl phosphate Hardener OZ: Oxazolidine-based curing agent (manufactured by Bayern) LB58: Di (2) -Ethylhexyl) phosphate

[0027]

EFFECT OF THE INVENTION The one-pack type moisture-curable urethane resin composition of the present invention has excellent storage stability and can control the curability without changing the viscosity and thixotropic properties after storage. Therefore, the one-component moisture-curable urethane resin composition of the present invention can be suitably used as a sealing agent, a waterproofing agent, a jointing agent, an adhesive, a paint, and the like.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takanobu Odori 2-1 Oiwake, Hiratsuka-shi, Kanagawa Yokohama Rubber Co., Ltd. Inside the Hiratsuka Factory (72) Inventor Hiroyuki Hosoda 2-1 Oiwake, Hiratsuka-shi, Kanagawa Yokohama Rubber F-term in Hiratsuka Factory (reference) 4J002 CK031 CK041 CK051 EX036 FD146 FD156 FD206 GH01 GJ01 GJ02

Claims (2)

[Claims] 1. A composition comprising a urethane prepolymer and a silyl phosphate, and a component other than the silis phosphate.
0.001 to 100 parts by weight of silyl phosphate
A one-component moisture-curable urethane resin composition containing 30 parts by weight. 2. The one-part moisture-curable urethane resin composition according to claim 1, wherein the silyl phosphate is a compound represented by the formula (1). Embedded image (R is an alkyl group, X is an organic group optionally having a hetero atom, and n represents an integer of 1 to 3.)