JPH1072520A - Blocked isocyanate composition, its production and aqueous dispersion containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a blocked isocyanate composition having a long-term storage stability by reacting a polyisocyanate composition containing 2,4'- diphenylmethane diisocyanate with an active hydrogen compound and a blocking agent. SOLUTION: A polyisocyanate composition (A) comprising 10-90wt.% 2,4'- diphenylmethane diisocyanate and 90-10wt.% 4,4'-diphenylmethane diisocyanate is reacted with 0.1-0.9 equivalent, per equivalent of the isocyanato groups of a component A, compound (B) having at least two active hydrogen atoms in the molecule for 1-10hr at 40-120 deg.C in an inert gas atmosphere to obtain an isocyanato-terminated isocyanate adduct. To this adduct is added a blocking agent in an among sufficient to block all of the terminal isocyanato groups over a period of 0.5-2hr in an inert gas atmosphere. The resulting mixture is reacted for 2-6hr at 40-120 deg.C to obtain a blocked isocyanate composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blocked isocyanate composition having improved long-term storage stability, a method for producing the composition, and an aqueous dispersion obtained by blending the composition. The blocked isocyanate composition obtained according to the present invention can be used as a crosslinking agent for a solvent-based adhesive,
Further, the blocked isocyanate composition dispersed in water,
It can be used as an adhesive for fibers, a crosslinking agent for rubber latex or emulsion, a waterproof agent for water and oil repellents, and the like.

[0002]

2. Description of the Related Art Conventionally, blocked isocyanate compounds have been used as crosslinking agents for solvent-based adhesives, and aqueous blocked isocyanate compositions have been widely used as crosslinking agents and modifiers for rubber latex or emulsion. Examples of the polyisocyanate component for producing the blocked isocyanate compound include 2,4- or 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and the like, or a mixture thereof. Adducts of dimers, trimers and polyols are generally used. Among these polyisocyanates, diphenylmethane diisocyanate, which is an aromatic polyisocyanate, or an adduct thereof is important from the viewpoints of performance such as crosslinkability, adhesion, and dissociation temperature, and from the viewpoint of cost and environmental hygiene. In addition, as an aqueous blocked isocyanate composition produced using diphenylmethane diisocyanate, a crystalline blocked isocyanate compound obtained by blocking the isocyanate group of 4,4'-diphenylmethane diisocyanate with a blocking agent may be used in a ball mill or the like in the presence of a surfactant. Those dispersed in water using a dispersing machine (for example, JP-A-57-5
No. 6584) or a liquid blocked isocyanate compound obtained by blocking an isocyanate group of an adduct of 4,4′-diphenylmethane diisocyanate and a polyol with an active hydrogen compound and emulsifying the mixture with various homogenizers in the presence of a surfactant (for example, Japanese Patent Publication No. 3-35432) has been proposed.

[0003]

However, when obtaining these blocked isocyanate compounds,
When 4'-diphenylmethane diisocyanate is used alone, the resulting blocked isocyanate compound is
Crystalline low molecular weight products that inhibit long-term storage stability (isocyanate monomer block and dimer block)
In addition, there was a problem that the blocked isocyanate compound settled and adhered to the bottom of the container due to a high molecular weight product of an adduct of 4,4'-diphenylmethane diisocyanate and a polyol, which made use difficult. In addition, when the blocked isocyanate composition dispersed in water is left for a long period of time, even if the blocked isocyanate compound separates from water or is mixed with another latex or emulsion, etc. In addition, there was a problem that the sedimentation and fixation of the material made it difficult to use.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve these problems, and as a result, 2,4 'at a specific ratio in a commonly used polyisocyanate composition.
-By mixing and using diphenylmethane diisocyanate, it was found that the storage stability of the blocked isocyanate was significantly improved both in the case of using an organic solvent solution and in the case of using an aqueous dispersion. It was completed. That is, the present invention provides (1) 2,
4'-diphenylmethane diisocyanate is used for 10 to 90
% By weight of a polyisocyanate composition containing 0.1% by weight based on isocyanate groups in the polyisocyanate composition.
A method for producing a blocked isocyanate composition comprising reacting a compound containing two or more active hydrogens in 0.9 equivalents of a molecule and a blocking agent in an amount sufficient to block unreacted isocyanate groups, (2) polyisocyanate composition Thing is,
2,4'-diphenylmethane diisocyanate is added to 30 to
The method for producing a blocked isocyanate composition according to the above (1), which comprises 70% by weight, (3) a polyisocyanate composition comprising 10 to 90% by weight of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate (4) The method for producing a blocked isocyanate composition according to the above (1), which comprises 90 to 10% by weight, (4) the compound having two or more active hydrogens in a molecule is a polyol having a molecular weight of 60 to 240. (5) the blocked isocyanate composition produced by the production method described in (1) above, and (6) the blocked isocyanate composition described in (4) above, a surfactant and water. Aqueous dispersion obtained by blending.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The polyisocyanate composition used in the present invention contains 2,4'-diphenylmethane diisocyanate in an amount of 10 to 90% by weight, preferably 30 to 90% by weight.
To 85% by weight, more preferably 55 to 80% by weight. If the mixing ratio of 2,4'-diphenylmethane diisocyanate is less than 10%, the effect of improving the storage stability is small, and if it is more than 90%, the storage stability and the crosslinkability deteriorate, which is not preferable.

The polyisocyanate compounds other than 2,4'-diphenylmethane diisocyanate used in the present invention include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2 -Butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4
Aliphatic diisocyanates such as 4,-or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, e.g.
3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5
5-trimethylcyclohexyl isocyanate, 4,
4'-methylenebis (cyclohexyl isocyanate), methyl 2,4-cyclohexane diisocyanate, methyl 2,6-cyclohexane diisocyanate,
Alicyclic diisocyanates such as 1,4-bis (isocyanatomethyl) cyclohexane and 1,3-bis (isocyanatomethyl) cyclohexane, for example, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, , 5
Naphthalene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate or a mixture thereof, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4, Aromatic diisocyanates such as 4'-diphenyl ether diisocyanate, 1,3- or 1,4-
Xylylene diisocyanate or a mixture thereof, ω,
ω'-diisocyanate 1,4-diethylbenzene,
1,3- or 1,4-bis (1-isocyanate-1
Araliphatic diisocyanates such as -methylethyl) benzene or mixtures thereof, triphenylmethane-4,
Organic triisocyanates such as 4 ', 4 "-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4'-
Polyisocyanate monomer such as organic tetraisocyanate such as diphenyldimethylmethane-2,2'-5,5'-tetraisocyanate, dimer, trimer, buret, allophanate, carbon dioxide gas derived from the above polyisocyanate monomer And a polyisocyanate having a 2,4,6-oxadiazinetrione ring obtained from the above and the polyisocyanate monomer. These can be used alone or in combination of two or more. Particularly preferred for the purposes of the present invention,
4,4'-diphenylmethane diisocyanate, 2,4
-Or 2,6-tolylene diisocyanate and mixtures thereof. These polyisocyanates other than 2,4'-diphenylmethane diisocyanate constitute 10 to 90% by weight, preferably 1 to 90% by weight of the polyisocyanate composition.
The content is 5 to 70% by weight, more preferably 20 to 45% by weight.

The compound having two or more active hydrogens in the molecule (hereinafter referred to as active hydrogen compound) used in the present invention includes, for example, known polyols. As the polyol, ethylene glycol,
Propylene glycol, triethylene glycol, glycerin, trimethylolmethane, trimethylolpropane, pentaerythritol, neopentyl glycol,
Polyhydric alcohols such as 1,6-hexylene glycol, butanediol, hexamethylene glycol, xylylene glycol, sorbitol and sucrose, ethylene oxide or propylene oxide, or addition polymerization of these polyhydric alcohols or polyamines The resulting polyether polyols, polytetramethylene ether polyols, polycarbonate polyols, polycaprolactone polyols, and the above polyhydric alcohols and, for example, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, sebacic acid, fumaric acid, maleic acid , Polyester polyols, polybutadiene polyols, acrylic polyols, castor oil, polyether polyol or polyester polyol obtained by reacting with a polybasic acid such as azelaic acid. Polymer polyols obtained by grafting a vinyl monomer ester polyols, and the like epoxy modified polyols. Among these, ethylene glycol, propylene glycol, triethylene glycol, glycerin, trimethylolmethane, trimethylolpropane, pentaerythritol,
Neopentyl glycol, 1,6-hexylene glycol, butanediol, hexamethylene glycol, xylylene glycol, sorbitol, etc.
A low molecular weight polyol of about 0 k is preferably used.

As blocking agents for isocyanate groups,
Any of those known per se can be used. Typical examples include alcohol-based blocking agents such as methanol and ethanol, phenol-based blocking agents such as phenol and cresol, formaldoxime, acetoaldoxime, methylethylketoxime, methylisobutylketoxime, cyclohexanone oxime, acetoxime, and diacetyl. Oxime blocking agents such as monooximes and benzophenone oximes; acid amide blocking agents such as acetanilide, ε-caprolactam and γ-butyrolactam; active methylene blocking agents such as dimethyl malonate and methyl acetoacetate; mercaptans such as butyl mercaptan Blocking agents, imide-based blocking agents such as succinimide and maleic imide, imidazole-based blocking agents such as imidazole and 2-methylimidazole, urea, and thiocyanate Urea-based blocking agents such as urea; carbamic acid-based blocking agents such as phenyl N-phenylcarbamate; amine-based blocking agents such as diphenylamine and aniline; and imine-based blocking agents such as ethyleneimine and polyethyleneimine. Among these, oxime-based blocking agents are preferably and conveniently used.

The amounts of the active hydrogen compound and the blocking agent used are such that the equivalent ratio to the isocyanate group in the polyisocyanate composition used is 0.1 to 0.9, respectively.
Preferably, the amount is in the range of 0.2 to 0.7, and an amount sufficient to react both the active hydrogen compound and the blocking agent together with all the isocyanate groups in the polyisocyanate composition, for example, an isocyanate group. Is in the range of 1.0 to 1.1. If the equivalent ratio of the active hydrogen compound to the isocyanate group exceeds 0.9, a large amount of a high molecular weight urethane compound is generated, which adversely affects the storage stability of the final product. When the equivalent ratio of the active hydrogen compound to the isocyanate group is less than 0.1, 2,
Even in the presence of 4'-diphenylmethane diisocyanate, the production of a block having a high crystallinity and a low molecular weight increases, which also impairs the storage stability. The order of the reaction of the polyisocyanate composition with the active hydrogen compound and the blocking agent does not matter. That is, first, the polyisocyanate composition and the active hydrogen compound are reacted under an excess of isocyanate groups, and then the blocking agent may be reacted to block unreacted isocyanate groups, or the polyisocyanate composition and the blocking agent may be reacted. Then, an active hydrogen compound may be reacted to react with an unreacted isocyanate group. More specifically, the active hydrogen compound and the polyisocyanate composition are simultaneously dropped under anhydrous conditions or the other is dropped into one of them, and heated at a temperature of 40 to 120 ° C. for 1 to 10 hours under an inert gas atmosphere. The reaction is performed to obtain an isocyanate adduct having an isocyanate group at a terminal. Then, 40 to 120 under an inert gas atmosphere.
While stirring at about ° C, an amount of a blocking agent capable of blocking substantially all of the terminal isocyanate is added dropwise over 0.5 to 2 hours, and then the reaction is further performed at the same temperature for 2 to 6 hours. The reaction can be performed in the presence or absence of a solvent. The end point of the reaction can be easily determined by a method such as disappearance of the peak of the infrared absorption spectrum of the isocyanate group. In the reaction for obtaining the block, a catalyst such as an organic metal compound, a tertiary amine, or a metal salt known per se can be used as necessary.

Examples of the organometallic catalyst include tin catalysts such as stannas octoate, dibutyltin diacetate and dibutyltin dilaurate, lead catalysts such as lead 2-ethylhexanoate, and tertiary amines.
For example, triethylamine, N, N-dimethylcyclohexylamine, triethylenediamine, N, N'-dimethylpiperazine, diazabicyclo (2,2,2) -octane and the like. Examples of the metal salt catalyst include cobalt naphthenate and calcium naphthenate. And lead naphthenate lithium oxide. The amount of these catalysts used is
It is usually 0.001 to 2 parts by weight, preferably 0.01 to 1 part by weight, based on 100 parts by weight of the polyisocyanate composition. In addition to the above-mentioned method, a highly stable blocked isocyanate composition can also be obtained by reacting a polyisocyanate composition with a blocking agent and then reacting a polyol in which all terminal isocyanates are blocked. The desired aqueous dispersion can be obtained by adding water to the thus obtained blocked isocyanate composition with stirring together with a surfactant. As the surfactant used, for example, sodium dodecylbenzenesulfonate, sodium lauryl sulfate,
Sodium dodecyl diphenyl ether disulfonate,
Anionic surfactants such as dialkyl succinate sodium sulfonate, nonionic surfactants such as polyoxyethylene alkyl ester and polyoxyethylene alkyl aryl ether, and alkyl betaine salts such as lauryl betaine and stearyl betaine salts , Lauryl-β-alanine, lauryl di (aminoethyl) glycine, octyldi (aminoethyl) glycine, and other amino acid type surfactants. These can be used alone or in combination of two or more. Among these, nonionic surfactants are preferred.

The amount of the surfactant used is usually 0.05 to 1 based on 100 parts by weight of the blocked isocyanate composition.
It is 5.0 parts by weight, preferably 0.1 to 10.0 parts by weight. The amount of water to be used is generally 30 to 500 parts by weight, preferably 50 to 300 parts by weight, based on 100 parts by weight of the blocked isocyanate composition. The obtained aqueous dispersion can be desolvated as required. Further, it can be further homogenized by various homogenizers.
The aqueous dispersion thus obtained is a fiber adhesive,
Extremely excellent performance as a cross-linking agent such as water and oil repellents, anti-staining agents, and water resistance agents.

[0012]

EXAMPLES Examples of the present invention will be described below in detail, but the present invention is not limited to these examples. Unless otherwise specified, parts and% in the examples mean "parts by weight" and "% by weight", respectively. Preparation of Blocked Isocyanate Example 1 50% 2,4'-isomer and 50% 4,4'-isomer
% Diphenylmethane diisocyanate 500%
Was dissolved in 764 parts of toluene, and 90 parts of 1,3-butanediol was added dropwise at 60 ° C. over 1 hour, followed by a reaction for 6 hours. Subsequently, 174 parts of methyl ethyl ketoxime was added and reacted for 2 hours to obtain a blocked isocyanate composition. Example 2 To 500 parts of the blocked isocyanate composition solution obtained in Example 1, 25 parts of polyoxyethylene alkylphenyl ether was added, and while stirring, 391 parts of water was gradually added, followed by homogenization using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%.

EXAMPLE 3 500 parts of diphenylmethane diisocyanate containing 60% of 2,4'-isomer and 40% of 4,4'-isomer were dissolved in 816 parts of toluene, and 1,3-butanediol 9
After 0 parts were added dropwise at 60 ° C. over 1 hour, the reaction was carried out for 6 hours. Next, 226 parts of caprolactam was added and reacted for 4 hours to obtain a blocked isocyanate composition. Example 4 To 500 parts of the blocked isocyanate composition solution obtained in Example 3, 25 parts of polyoxyethylene alkylphenyl ether was added, and 391 parts of water was gradually added with stirring, followed by emulsification using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%. Example 5 500 parts of diphenylmethane diisocyanate containing 50% of 2,4'-isomer and 50% of 4,4'-isomer are dissolved in 654 parts of toluene, and 90 parts of 1,3-butanediol are added at 60 DEG C. After the dropwise addition over 1 hour, the reaction was carried out for 6 hours. Next, 64 parts of methanol was added and reacted for 4 hours to obtain a blocked isocyanate composition. Example 6 To 500 parts of the blocked isocyanate composition solution obtained in Example 5, 25 parts of polyoxyethylene alkylphenyl ether was added, and while stirring, 391 parts of water was gradually added, followed by homogenization using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%.

Example 7 500 parts of diphenylmethane diisocyanate containing 90% of 2,4'-isomer and 10% of 4,4'-isomer were dissolved in 764 parts of toluene, and 90 parts of 1,3-butanediol was dissolved in 60 parts of 60 parts of toluene. After dropping at 1 ° C. over 1 hour, the reaction was carried out for 6 hours. Subsequently, 174 parts of methyl ethyl ketoxime was added and reacted for 2 hours to obtain a blocked isocyanate composition. Example 8 To 500 parts of the blocked isocyanate composition solution obtained in Example 7, 25 parts of polyoxyethylene alkylphenyl ether was added, and while stirring, 391 parts of water was gradually added, followed by emulsification using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%. Example 9 500 parts of diphenylmethane diisocyanate containing 10% of 2,4'-isomer and 90% of 4,4'-isomer were dissolved in 764 parts of toluene, and 90 parts of 1,3-butanediol was added at 60 ° C. After dropping over time, the reaction was performed for 6 hours. Subsequently, 174 parts of methyl ethyl ketoxime was added and reacted for 2 hours to obtain a blocked isocyanate composition. Example 10 To 500 parts of the blocked isocyanate composition solution obtained in Example 9, 25 parts of polyoxyethylene alkylphenyl ether was added, and 391 parts of water was gradually added with stirring, followed by emulsification using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%.

Example 11 500 parts of diphenylmethane diisocyanate containing 70% of 2,4'-isomer and 30% of 4,4'-isomer were dissolved in 764 parts of toluene, and 90 parts of 1,3-butanediol was added to 60 parts of toluene. After dropping at 1 ° C. over 1 hour, the reaction was carried out for 6 hours. Subsequently, 174 parts of methyl ethyl ketoxime was added and reacted for 2 hours to obtain a blocked isocyanate composition. Example 12 To 500 parts of the blocked isocyanate composition solution obtained in Example 11, 25 parts of polyoxyethylene alkylphenyl ether was added, and while stirring, 391 parts of water was gradually added, followed by homogenization using a homomixer. afterwards,
The toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%. Example 13 500 parts of diphenylmethane diisocyanate containing 30% of 2,4'-isomer and 70% of 4,4'-isomer were dissolved in 764 parts of toluene, and 90 parts of 1,3-butanediol was added at 60 ° C. After dropping over time, the reaction was performed for 6 hours. Subsequently, 174 parts of methyl ethyl ketoxime was added and reacted for 2 hours to obtain a blocked isocyanate composition. Example 14 To 500 parts of the blocked isocyanate composition solution obtained in Example 13, 25 parts of polyoxyethylene alkylphenyl ether was added, and 391 parts of water was gradually added with stirring, followed by emulsification using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%.

Example 15 500 parts of diphenylmethane diisocyanate containing 50% of 2,4'-isomer and 50% of 4,4'-isomer were dissolved in 764 parts of toluene, and 174 parts of methyl ethyl ketoxime was added at 60 ° C for 1 hour. Then, the mixture was reacted for 2 hours. Next, 90 parts of 1,3-butanediol was added and 6
The reaction was carried out at 0 ° C. for 6 hours to obtain a blocked isocyanate composition. Example 16 To 500 parts of the blocked isocyanate composition solution obtained in Example 15, 25 parts of polyoxyethylene alkylphenyl ether was added, and 391 parts of water was gradually added with stirring, followed by emulsification using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%. Example 17 2,4'-diphenylmethane diisocyanate was added to 250
And 174 parts of tolylene diisocyanate 80 were dissolved in 688 parts of toluene, and 1,3-butanediol 9
After 0 parts were added dropwise at 60 ° C. over 1 hour, the reaction was carried out for 6 hours. Then, 174 parts of methyl ethyl ketoxime was added and reacted for 2 hours to obtain a blocked isocyanate composition. Example 18 25 parts of polyoxyethylene alkylphenyl ether was added to 500 parts of the blocked isocyanate composition solution obtained in Example 17, 391 parts of water was gradually added with stirring, and the mixture was emulsified with a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%.

Comparative Example 1 500 parts of 4,4'-diphenylmethane diisocyanate was dissolved in 764 parts of toluene, and 90 parts of 1,3-butanediol was added dropwise at 60 ° C. over 1 hour, followed by a reaction for 6 hours. Then, 174 parts of methyl ethyl ketoxime was added and reacted for 2 hours to obtain a blocked isocyanate composition. Comparative Example 2 To 500 parts of the blocked isocyanate composition solution obtained in Comparative Example 1, 25 parts of polyoxyethylene alkylphenyl ether was added, and 391 parts of water was gradually added with stirring, followed by emulsification using a homomixer. Thereafter, toluene was distilled off under reduced pressure to obtain an aqueous dispersion having a solid content of 40%. Comparative Example 3 250 parts of 4,4'-diphenylmethane diisocyanate was dissolved in 677 parts of toluene, 174 parts of methyl ethyl ketoxime was added dropwise at 60 ° C. over 1 hour, and the reaction was further performed for 5 hours to obtain a blocked isocyanate compound. Comparative Example 4 From the obtained blocked isocyanate compound solution, toluene was removed and dried to 250 parts, and 25 parts of polyoxyethylene alkylphenyl ether and 412.5 parts of water were added.
And stirred with a ball mill for about 24 hours to obtain a solid content of 40%.
% Of an aqueous dispersion of blocked isocyanate.

Storage Stability Test 1 The storage stability at 40 ° C. of the blocked isocyanate composition solutions prepared in Examples 1, 3, 5, 7, 9, 11, 13, 15, 17 and Comparative Examples 1 and 3 was determined. investigated. The results are shown in [Table 1]. The evaluation was performed by the following method. Evaluation method Thickness of fixed sediment after standing The block isocyanate composition solution was applied to an inner diameter of 21 mm.
The solution was placed in a 200 mm long test tube so that the liquid depth was 100 mm, sealed tightly with a silicone rubber stopper, and the thickness of the fixed sediment generated after standing in a 40 ° C. thermostat for 30 days was expressed in mm. The smaller the value, the better the storage stability.

[Table 1]

Storage stability test 2 Examples 2, 4, 6, 8, 10, 12, 14, 16, 18
The storage stability at 40 ° C. of the aqueous blocked isocyanate compositions produced in Comparative Examples 2 and 4 was investigated. The results are shown in [Table 2]. The evaluation was performed by the following method. Evaluation method Phase separation after standing A block isocyanate aqueous dispersion was placed in a test tube having an inner diameter of 21 mm and a length of 200 mm so that the liquid depth was 100 mm, sealed with a silicone rubber stopper, and placed in a thermostat at 40 ° C. The liquid depth of the transparent separation layer formed above the liquid phase after standing for 30 days is expressed in mm. The smaller the numerical value, the better the storage stability. The thickness of the adhered sediment after standing The block isocyanate aqueous dispersion after the phase separation evaluation after standing was gently removed from the test tube, and the thickness of the adhered sediment at the bottom of the test tube was expressed in mm. The smaller the value, the better the storage stability.

[0020]

[Table 2]

Storage stability test 3 Examples 2, 8, 10, 12, 14, 18 and Comparative Example 2,
The aqueous blocked isocyanate composition prepared in 4 was mixed with another aqueous latex, and the storage stability and adhesion when left at 40 ° C. were investigated. The results are shown in [Table 3]. The evaluation was performed by the following method. Evaluation method Thickness of sediment adhered after standing NBR latex (Crosslen NA- manufactured by Takeda Pharmaceutical Co., Ltd.)
20) and a mixture having a solid content ratio of 100/10 of the aqueous dispersion of blocked isocyanate, an inner diameter of 21 mm and a length of 200 m
m into a test tube so that the liquid depth is 100 mm,
The thickness of the solidified sediment formed after being sealed with a silicone rubber stopper and allowed to stand in a thermostat at 40 ° C. for 30 days is expressed in mm. The smaller the numerical value, the better the storage stability.

Method for measuring adhesive strength The test is based on the test method for peeling adhesive strength of JIS K9854 adhesive. 1. NBR latex (Crosslen N manufactured by Takeda Pharmaceutical)
A-20) and an aqueous dispersion of blocked isocyanate at a solid content ratio of 100/10 are placed in a 1-liter plastic container, left in a 40 ° C. incubator for 30 days, and then used as a thickener (Daiichi Kogyo Pharmaceutical AG). Gum) and water to increase viscosity to 2000
It is adjusted to 0 mPa · s and the solid content to 35% by weight. No. 2.9 Cotton canvas is coated with an adhesive so that the apparent coating amount is 1 kg / m ^2, and a nylon cloth with a basis weight of 190 g / m ² is stuck without open time, and the length is lengthened with a 5 kg / f hand roller. Press and crimp 5 times without reciprocating in the direction. Then, after standing for 24 hours in an atmosphere at a temperature of 20 ° C and a humidity of 65% for 24 hours, heating in an oven at 160 ° C for 10 minutes, and then again for 24 hours in an atmosphere of a temperature of 20 ° C and a humidity of 65%, the cured sample is cut into 25 mm width. The test piece was a normal test piece. Further, a sample immersed in water at 20 ° C. for 24 hours for a water resistance test was also prepared. 3. Using a tensile tester, 100 mm
The T-peel test was performed at a tensile speed of / min. In addition,
The water resistance test measured the sample which was wet. The test was performed on each of the five test pieces in both normal state and water resistant strength. The test results are shown in [Table 3].

[0022]

[Table 3]

[0023]

The blocked isocyanate composition obtained according to the present invention exhibits a long-term high storage stability when it is mixed with water together with a surfactant to form an aqueous dispersion or an organic solvent solution. At the same time, it exhibits extremely excellent performance as a crosslinking agent such as an adhesive such as a fiber, a water repellent, an oil repellent, and a stain inhibitor, and a water resistant agent.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 75/04 NGA C08L 75/04 NGA D06M 15/568 D06M 15/568 (72) Inventor Masaaki Tsuji 536-122 Minamigasa-cho, Kusatsu-shi, Shiga

Claims (6)

[Claims] 1. A polyisocyanate composition containing 10 to 90% by weight of 2,4'-diphenylmethane diisocyanate, wherein two of the polyisocyanate groups are contained in a molecule of 0.1 to 0.9 equivalent based on isocyanate groups in the polyisocyanate composition. A method for producing a blocked isocyanate composition, comprising reacting a compound containing active hydrogen and a blocking agent in an amount sufficient to block unreacted isocyanate groups. 2. The method according to claim 1, wherein the polyisocyanate composition is 2,4'-
30-70% by weight of diphenylmethane diisocyanate
The method for producing a blocked isocyanate composition according to claim 1, wherein the composition comprises: 3. A polyisocyanate composition comprising 2,4'-
10-90% by weight of diphenylmethane diisocyanate
And 4,4'-diphenylmethane diisocyanate in 90
The method for producing a blocked isocyanate composition according to claim 1, wherein the composition comprises from 10 to 10% by weight. 4. The compound containing two or more active hydrogens in the molecule is a polyol having a molecular weight of 60 to 240.
A method for producing the blocked isocyanate composition as described above. 5. A blocked isocyanate composition produced by the production method according to claim 1. 6. An aqueous dispersion comprising the blocked isocyanate composition according to claim 4, a surfactant and water.