A one-pack type moisture curable urethane composition comprising a urethane prepolymer and an amine catalyst, wherein 0.002 to 50 parts by weight, based upon 100 parts by weight of the urethane prepolymer, of phosphonic ester compounds, phosphonous ester compounds, phosphinous ester compounds or phosphine compounds or any mixture thereof is compounded to give the urethane composition having an improved storage stability, without decreasing the catalyst activity even when an amine catalyst having a high catalytic activity dimethylamino group structure etc. is used.

TECHNICAL FIELD
 The present invention relates to a one-pack type moisture curable urethane
 composition suitable for use as, for example, a sealing agent for
 automobiles, buildings and structures, an adhesive, and a coating agent.
 More specifically, it relates to a one-pack type moisture curable urethane
 composition having an excellent storage stability in the absence of
 moisture without decreasing a catalyst activity and having a sufficient
 curability with atmospheric moisture.
 BACKGROUND ART
 To ensure the storage stability of curable urethane compositions,
 especially one-pack type moisture curable urethane compositions, malonate
 compounds such as diethyl malonate (DEM), dimethyl malonate (DMM),
 isopropyl malonate (IPM), etc. have been heretofore used. However, when
 the malonate compounds are used, in the presence of an isocyanate group,
 together with a relatively highly active catalyst having a structure such
 as a dimethylamino group, the catalyst activity is decreased. Therefore,
 there are problems that only catalysts having extremely limited structure
 such as those having a morpholine structure can be used. For this reason,
 since a large amount of catalysts having a relatively weak activity such
 as morpholine-based catalysts, etc. should be used, the use of the
 one-pack type moisture curable urethane compositions is extremely limited
 from the viewpoints of, for example, the curability characteristics and
 high cost.
 DISCLOSURE OF INVENTION
 Accordingly, the objects of the present invention are to provide a one-pack
 type moisture curable urethane composition capable of increasing the
 storage stability thereof without decreasing the catalyst activity even
 when amine catalysts having, for example, a dimethylamino group structure
 having a high catalytic activity are used.
 In accordance with the present invention, there is provided a one-pack type
 moisture curable urethane composition comprising a urethane prepolymer and
 an amine catalyst and 0.002 to 50 parts by weight, based upon 100 parts by
 weight of the urethane prepolymer, of at least one storage stabilizer
 selected from the group consisting of phosphonic ester compounds,
 phosphonous ester compounds, phosphinous ester compounds and phosphines.
 BEST MODE FOR CARRYING OUT THE INVENTION
 According to the present invention, as mentioned above, the storage
 stability of the one-pack type moisture curable urethane composition can
 be increased, without impairing the activity of the amine catalysts by
 compounding thereinto phosphonic ester compounds, phosphophonous ester
 compounds, phosphinous ester compounds or phosphine compounds or any
 mixtures thereof. Thus, when phosphonic ester compounds, phosphonous ester
 compounds, phosphinous ester compounds or phosphine compounds or any
 mixtures thereof are used as a storage stabilizer for a one-pack type
 moisture curable urethane composition, the use of a catalyst having a
 structure such as a dimethylamino group becomes possible, various
 curability phenomena can be selected and a catalyst having a high activity
 can be used. As a result, the use of the composition becomes advantageous
 from the viewpoints of the cost.
 The urethane prepolymers formulated into the urethane composition according
 to the present invention are known substances and include, for example,
 polyether polyols having a desired isocyanate functionability of 2.2-3.0
 obtained by reacting 4,4'-diphenylmethane diisocyanate to a mixture of a
 polyol component such as polyetherpolyol having 3 or more hydroxyl group
 per molecule, e.g., polyoxypropylene triol, polyoxyethylene triol and a
 diol component such as polyether diol having 2 hydroxyl group per
 molecule, e.g., polypropylene ether diol, polyethylene ether diol. The
 preferable urethane prepolymers are those obtained by reacting mixtures of
 polyether triols having a number average molecular weight of 1000-7000,
 preferably 4000-6000 and polyether diols having a number average molecular
 weight of 1000-3000, preferably 1500-2500, with 4,4'-diphenylmethane
 diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, etc.,
 in such a manner that an equivalent ratio of NCO/OH becomes 1.1-2.5,
 preferably 1.5-1.9.
 The curing catalysts usable in the present invention are amine catalysts
 generally used in the one-pack type moisture curable urethane composition,
 such as, for example, dimorpholinodiethyl ether, N,N-dimethylcyclohexyl
 amine, N,N-dimethylaminoethyl morpholine, bis(2-dimethylaminoethyl)ether,
 N-methylmorpholine, triethylenediamine, 1-isobutyl-2-methylimidazol,
 N,N'-dimethyl piperazine, pentamethyldiethyl triamine, etc. Although there
 are no specific limitations to the amounts of the catalyst, the preferable
 amount is 0.002-10 parts by weight, more preferably 0.02-6 parts by
 weight, based upon 100 parts by weight of the urethane prepolymer.
 The one-pack type moisture curable polyurethane compositions according to
 the present invention include, as a storage stabilizer, 0.002-50 parts by
 weight, preferably 0.005-3 parts by weight, based upon 100 parts by weight
 of the urethane prepolymer, of phosphonic ester compounds, phosphonous
 ester compounds, phosphinous ester compounds and/or phosphine compounds.
 When the formulating amount of the phosphonic ester compounds, phosphonous
 ester compounds, phosphinous ester compounds and/or phosphine compounds is
 too small, the storage stability and the catalyst deactivation cannot be
 unpreferably suppressed, whereas when the amount is too large, the
 decrease in the properties after the curing becomes unpreferably
 remarkable.
 The phosphonic ester compounds, phosphonous ester compounds, phosphinous
 ester compounds and/or phosphine compounds usable, as a storage
 stabilizer, in the present invention include, for example, organic
 phosphorous compounds having the formula:
EQU R.sub.n --P--(--OR).sub.3-n
 wherein R represents a univalent or bivalent linear or cyclic organic group
 and n is an integer of 0-3.
 Examples of the phosphonic ester compounds usable in the present invention
 are triphenyl phosphite, tris(nonylphenyl) phosphite, triethyl phosphite,
 triisopropyl phosphite, triisobutyl phosphite, tridecyl phosphite,
 triisodecyl phosphite, tris(tridecyl)phosphite,
 tri(2-ethylhexyl)phosphite, diphenylmono(2-ethylhexyl)phosphite,
 diphenylmonodecyl phosphite, diphenylmono(tridecyl)phosphite, dilauryl
 hydrogen phosphite, dioleyl hydrogen phosphite, diphenyl hydrogen
 phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyl
 tetra(tridecyl)pentaerythritol tetraphosphite,
 tetra(tridecyl)-4,4'-isopropylidene diphenyldiphosphite, trilauryltrithio
 phosphite, bis(tridecyl)pentaerythritol diphosphite,
 bis(nonylphenyl)pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)
 phosphite, tricyclohexyl phosphite, dicyclohexyl-2,4-di-t-butylphenyl
 phosphite, hydrogenated bisphenol A-pentaerythritol phosphite polymer,
 hydrogenated bisphenol A phosphite polymer, etc.
 The phosphonous ester compounds usable in the present invention include
 phenyl phosphonous diethyl ester, 2-phenyl-1,3,2-dioxaphosphorun, etc. The
 phosphinous ester compounds include diphenylphosphinous ethyl ester,
 diphenylphosphinous butyl ester, etc.
 Examples of the phosphine compounds usable in the present invention are
 triphenyl phosphine, triorthotolyl phosphine, trimethatolyl phosphine,
 triparatolyl phosphine, tris-4-methoxyphenyl phosphine, diphenylcyclohexyl
 phosphine, dicyclohexylphenyl phosphine, tricyclohexyl phosphine, trioctyl
 phosphine, tributyl phosphine, 1,2-bis(diphenylphosphino)ethane,
 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane,
 tribenzylphosphine, etc.
 The one-pack type moisture curable urethane composition according to the
 present invention may further contains, in addition to the above-mentioned
 essential components, fillers, plasticizers, solvents, etc., which are
 inactive to the isocyanate group, to impart the desired properties, etc.
 Examples of the fillers are carbon blacks, clays, talcs, calcium
 carbonate, etc. or any mixture thereof. Examples of the plasticizers are
 phthalic acid derivatives such as dibutyl phthalate, dioctyl phthalate,
 derivatives of tetrahydrophthalic acid, azelaic acid, maleic acid,
 trimellitic acid, isophthalic acid, adipic acid, itaconic acid, citric
 acid, etc. Examples of the solvents are aromatic hydrocarbon solvents such
 as toluene, xylene, etc.
 Although there are no limitations in the urethane composition of the
 present invention, the components, other than the curing catalyst and
 solvent, are sufficiently mixed under a reduced pressure to be uniformly
 dispersed and, then, the curing catalyst dissolved in a solvent such as
 xylene is added, followed by further thoroughly mixing under a reduced
 pressure to obtain the desired composition.