JPS59108021A - Preparation of polyurethane solution - Google Patents

Abstract

PURPOSE:To prepare a polyurethane solution having excellent weather resistance and yellowing resistance and high solution stability, in a short time, by carrying out the chain extension reaction of a prepolymer with a diamine in a ketone solvent in the presence of a specific amount of water. CONSTITUTION:The objective polyurethane solution is prepared by reacting a polymeric diol having a molecular weight of 500-5,000 (e.g. polyether diol, etc.) with excess aliphatic diisocyanate (e.g. hexamethylene diisocyanate) and/or cycloaliphatic diisocyanate (e.g. 1,4-cyclohexane diisocyanate), and carrying out the chain extension reaction of the resultant prepolymer having terminal isocyanate group with a branched-chain aliphatic diamine and/or cycloaliphatic diamine in an organic solvent containing a ketone in the presence of 2.0-5.0wt%, based on the organic solvent, of water.

Description

[Detailed description of the invention] The present invention relates to a method for producing polyurethane bath liquid.

More specifically, the present invention relates to a method for producing a polyurethane solution that has excellent weather resistance, yellowing resistance, and solution stability.

Ketone solvents such as methyl ethyl ketone are widely used as solvents for polyurethane resins because of their easy volatility. However, the chain elongation reaction with aliphatic or alicyclic diamines in organic solvents containing ketone solvents takes longer to complete than the chain elongation reactions in organic solvents that do not contain ketone solvents. In addition, if the reaction is completed before it is completed, the reaction will proceed during storage and the viscosity of the polyurethane solution will inevitably change.

The present inventors conducted extensive research to improve the reactivity of the chain elongation reaction using aliphatic or alicyclic diamines in ketone solvents, and as a result, they found that the chain elongation reaction can be carried out in the presence of a specific amount of water. It was found that the reaction was completed in a short time, and that a polyurethane m solution with substantially no unreacted amine and excellent solution stability could be obtained, leading to the present invention.

That is, 1 the present invention comprises a polymeric diol (a) having a molecular weight of 500 to 5000, an excess of aliphatic diisocyanate and/or
Or a prepolymer having an isocyanate group at the end obtained by reacting with an alicyclic diisocyanate (b) (
5) with a branched aliphatic diamine and /6 or alicyclic diamine 03) in an organic solvent containing a ketone solvent, 0.0% based on the weight of the organic solvent used.
This is a method for producing a polyurethane solution characterized by carrying out a chain extension reaction in the presence of 2 to 5% by weight of water.

Polymer diols (a) having a molecular weight of 500 to 5,000 used in the production of the prepolymer used in the present invention include polyether diols, polyester diols,
Examples include polyether ester diols, polymer diols, and mixtures of two or more thereof. Polyether diols include those obtained by polymerizing or copolymerizing (block or random) alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.), heterocyclic ethers (tetrahydrofuran, etc.),
Examples include polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random) glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, polyoctamethylene ether glycol, and mixtures of two or more thereof. Polyester diols include dicarboxylic acids (adipic acid, succinic acid, sebacic acid.

glutaric acid, maleic acid, fumaric acid, phthalic acid, etc.) and glycols (ethylene glycol, propylene glycol, 1.4-butanediol, 1.6-hexanediol, 1.8-octamethylenediol).

Neopentyl glycol, bishydroxymethylcyclohexane, bishydroxyethylbenzene.

alkyl dialkanolamines, etc.), such as polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyethylene/propylene adipate; polylactone diols, such as polycaprolactone diol; and 62 or more of these A mixture can be mentioned. As polyether ester diols, ether group-containing diols (the above-mentioned polyether diols, diethylene glycol, triethylene glycol, dipropylene glycol, etc.) or mixtures of these with other glycols can be used with the above dicarboxylic acids or dicarboxylic acid anhydrides (phthalic anhydride, etc.). , maleic anhydride, etc.) and those obtained by reacting with alkylene oxides, such as polyC polytetramethylene ether) adipate. The average molecular weight of polymeric diols (based on hydroxyl value measurement) is usually 500~
5000°, preferably 700 to 4000, particularly preferably 1000 to 3500.

In addition to the high molecular diol (a), a low molecular diol can also be used in combination if necessary. Examples of low-molecular diols include the glycols and their low-mole alkylene oxide adducts (molecular weight less than 500) listed as raw materials for the polyester diols.

The amount of low molecular weight diol is 20% by weight based on the high molecular weight diol.
The content is particularly preferably 10% by weight or less.

High molecular diols and low molecular diols contain small amounts (e.g. 0
．． (up to 5%) water may be present.

Also, Japanese Patent Application No. 57-48480 and Japanese Patent Application No. 57-
Molecular weight 32 as described in No. 48866
A small amount (0.02 to 0.3 equivalents per equivalent of diol) of a monohydric alcohol having a molecular weight of 400 to 400 can also be used in combination.

The aliphatic diisocyanate and alicyclic diisocyanate (b) used in the production of the prepolymer (2) include aliphatic diisocyanates having 2 to 12 carbon atoms, such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate.

Lysine diisocyanate; alicyclic diisocyanate having 4 to 18 carbon atoms such as 1,4-cyclohexane diisocyanate, 1-isocyanate-3-isocyanate methyl-8,5,5-)limethylcyclohexane, 4.4
'-Dicyclohexylmethane diisocyanate, methylcyclohexylene diisocyanate, isopropylidene dicyclohexyl-44'-diisocyanate; modified products of these polyisocyanates (carposiimide, uretdione).

uretimine group-containing modified products); and mixtures of two or more of these. Preferred among these are cycloaliphatic diisocyanates, especially 1.4-cyclohexane diisocyanate, 1-isocyanate-3-isocyanatomethyl-3,55-trimethylcyclohexane and 4,4'-dicyclohexylmethane diisocyanate.

When producing prepolymer (3) by reacting polymeric diol (a) and, if necessary, low-molecular diol, monohydric alcohol, and water and excess (b), NC07on ratio [
(b) NGO and (a) and, if necessary, a low molecular diol.

The equivalent ratio of monohydric alcohol to water is usually 1.5/1 to 3.
/1 preferably within the range of 1.6/l to 2.5/□.

If the NCOZ OH ratio is less than 1.5/, the resulting polyurethane will have poor mechanical strength, and if it exceeds 3/1, the resulting polyurethane will not be sufficiently dissolved in the solvent, resulting in a uniform and stable polyurethane. It is difficult to form a solution and is not preferred.

In producing prepolymer (8) by reacting (a) and (1)), the method and order of adding (a), (b) and, if necessary, low molecular diol are not particularly limited. These may be mixed at the same time, or two or more of the components may be mixed in advance, and then the remaining components may be added.

When using monohydric alcohol, please apply for patent application No. 51-48480.
No. 57-48366 and the method described in Japanese Patent Application No. 57-48366. In the synthesis of prepolymers, the reaction temperature is usually 50 to 130°C, preferably 60 to 120°C.
It is ℃. The reaction time is usually 2 to 10 hours, preferably 3 hours.
~7 hours. The reaction is usually carried out without a solvent, but it can also be carried out in a solvent. Further, although a catalyst is not particularly necessary, a catalyst such as an organic tin compound such as dibutyltin dilaurate or dioctyltin dilaurate, or an organic lead compound such as lead octylate may be used depending on the case. The end point of the reaction can be confirmed by measuring the NGO content. The NGO content is, for example, 1 to 10
% is preferably 2 to 8%.

Branched aliphatic diamines and/or alicyclic diamines a3) used in the present invention include branched aliphatic diamines having 3 to 12 carbon atoms, such as 1,2-propylene diamine,
2.2.4-) Limethylhexamethylene diamine; alicyclic diamine having 4 to 18 carbon atoms, such as 1-amino-3
-aminomethyl-3,55-trimethylcyclohexane, dicyclohexylmethane-44'-diamine, isopropylidene dicyclohexyl-44'-diamine, 1.
Examples include 4-diaminocyclohexane; and mixtures of two or more thereof. Among these, preferred are 1-amino-3-aminomethyl-8,5,5-)limethylcyclohexane and dicyclohexylmethane-4,4'-diamine. A part of the branched aliphatic diamine and/or alicyclic diamine (for example, 60 mol% or less, especially 40 mol% or less) is added to a straight chain aliphatic diamine (alkylene diamine having 2 to 12 carbon atoms, such as ethylene diamine, propylene diamine, hexamethylene diamine, etc.). diamine).

Next, examples of ketone solvents used in the present invention include acetone, methyl ethyl ketone (hereinafter referred to as MEK), and methyl isobutyl ketone.

MEK and methyl isobutyl ketone are preferred.

Moreover, the ketone solvent can also be used in combination with other solvents. Such solvents include esters (acetate, butyl acetate, etc.), ethers (tetrahydrofuran, etc.), aromatic hydrocarbons (toluene, xylene, etc.), alcohols (meth/-Jv, ethanol, isopropyl alcohol, etc.). , polyhydric alcohol derivatives (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc.), and mixed solvents of two or more of these. Among these, preferred are ethyl acetate, butyl acetate, tetrahydrofuran, toluene, xylene, methanol, ethanol, isopropyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and mixed solvents of two or more of these.

The proportion of the ketone solvent in the organic solvent can be varied as long as it can dissolve the produced polyurethane, but generally 2.
The content is 0% by weight or more, preferably 30% by weight or more. The alcohol solvent is preferably 50% by weight or less.

The amount of organic solvent used is such that the weight ratio of prepolymer (a) to solvent is usually 10/9 to 5015, preferably 20/8.
The amount falls within the range of ~45155.

Further, in the present invention, the amount of water used is 0.02 to 50% by weight based on the total amount of the organic solvent used, and particularly preferably 0.3 to 50% by weight.
~3.0% by weight. If the amount of water used is less than 0.2%, the time required to complete the reaction will be longer. Moreover, if the amount is more than 5%, the drying properties of the obtained polyurethane solution will be slow, causing a practical problem.

Water may be added in advance to the solvent used, or may be added to a prepolymer solvent solution that has been uniformly diluted by adding a solvent to the prepolymer.

The ratio of aliphatic diamine and/or alicyclic diamine used is such that the amine group of the diamine is usually 0.6 to 10 equivalents per equivalent of isocyanate group in the obtained prepolymer.
The amount is preferably 0.7 to 0.95 equivalents.

In addition, dialkylamine (
Mono- or di-alkanolamines (eg monoethanolamine, jetanolamine) can be used. The proportion of the monoamine used is such that the amino group of the monoamine is usually 0 to 0.4 equivalent, preferably 0.05 to 0.3 equivalent, per equivalent of the isocyanate group of the prepolymer. The total amount of amino groups in the monoamine and diamine is usually 0.9 to 1.02 equivalents, preferably 0.02 to 1.02 equivalents per equivalent of isocyanate groups in the prepolymer.
It is 95 to 1.01 equivalent. The monoamine may be added before the chain elongation reaction, added at the same time as the diamine during the chain elongation reaction, or added after the chain elongation reaction is completed to carry out the reaction.

The chain elongation reaction is usually carried out in a solvent at 70°C or lower, preferably at 60°C.
It is carried out at a temperature of ~20°C. Reaction time is usually 10 minutes ~]
'iJ) time, preferably 30 minutes to I hour. An example of a reaction method is to gradually drop diamine or this solvent solution (the solvent is the same as that described above) into a prepolymer solvent solution of a predetermined concentration maintained at a predetermined temperature, for example, about 40°C. . It is preferable that water be included in the prepolymer solution in advance or added to the prepolymer solution at the same time as the diamine, but it can also be added during the chain extension reaction. In addition, in the chain extension reaction, water does not substantially participate in the reaction, and almost all of the water remains in the polyurethane solution produced. P.

The solid content concentration of the polyurethane solution obtained by the present invention is usually 10 to 60%, preferably 20 to 50%.

Its viscosity is usually t,ooo~200,0 (10 cps/
The temperature was 20° C. (30% by weight solution (solvent: MEK:isopropyl alcohol-2=1 weight ratio)). The unreacted amine content is usually 0.0 in total amine value (number of KOHO mg required to neutralize hydrochloric acid equivalent to amine in 1 g of sample).
03 or less (substantially no unreacted amine exists). The color tone is APHA (Hellige AquaT
Hasen, measured in esters (platinum cobalt scale), is usually between 10 and 200.

According to the present invention, by carrying out the chain extension reaction with a branched aliphatic diamine or alicyclic diamine in an organic solvent containing a ketone solvent in the presence of water, the time required to complete the reaction is significantly shortened. The reason why the reaction time is shortened is not necessarily clear, but it is thought to be because the strong affinity between the ketone solvent and the diamine is alleviated by water.

The polyurethane solution obtained according to the present invention shows little change in viscosity even when stored for a long period of time (for example, from one month to several months) and does not become noticeably colored (no to slightly yellow coloring without yellow to brown coloration). It is a polyurethane solution with extremely high solution stability. Moreover, the elasticity, abrasion resistance, and mechanical strength (tensile, tear, etc.) of the polyurethane resin obtained from this are also good.

Because of the above effects, the polyurethane solution obtained by the present invention is extremely useful as a binder for paints, a binder for printing inks, or as a coating material for textiles, nonwoven fabrics, etc.

When used as a binder for printing ink, the method of use, composition, etc. are the same as those of conventional methods; for example, those described in JP-A-51-94807 can be applied.

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. (In the following, Part 1
%, each ratio is 1% by weight.

Indicates weight ratio. ) Example 1 1500 parts of polytetramethylene ether glycol with an average molecular i of 1500 and 444 parts of 1-isocyanate-3-isocyanatemethyl-8,5,5-)dimethylcyclohexane were charged into a polymerization vessel, and a nitrogen gas atmosphere was placed under stirring. The NCO content was reduced to 4 by reacting at 105°C for 4 hours in
．． A 30% terminal NCO prepolymer was obtained.

Next, 486 parts of the terminal NCO prepolymer with an NGO content of 430% and MEK 756 with a water content of 0.03% were obtained.
1 part and 378 parts of isopropyl alcohol with a water content of 10.07% were placed in a separate polymerization vessel, and after uniformly dissolving, 6 parts of water was added.
2 parts were added and mixed uniformly. Then 1-amino-3-
Aminomethyl-8,5,5-)trimethylcyclohexane 3F, F part and jetanolamine 515 parts with a moisture content of 0
．． A mixture solution of 67 parts of MEK with a water content of 0.07% and 33 parts of isopropyl alcohol with a water content of 0.07% was gradually added with stirring, and chain elongation was carried out at 50°C for 2 hours. (At this point, the water content of the reactant is 0.0% based on the weight of the solvent used.
It was 55%. ) The NC0% of the reactant was 0005% or less, the total amine value was 0.03 or less, and the chain elongation reaction was substantially completed.

The thus obtained polyurethane solution had a solid content concentration of 30.
% and the viscosity was 1,0,000 cps/20°C and the color of the solution was 30 in APHA.

Even after storage for 2 months, the viscosity remains 9,700 cps/20℃
The color tone was extremely stable with an APHA rating of 90, and no abnormalities were observed.

A mixture of 30 parts of titanium oxide mixed with 30 parts of this polyurethane solution and diluted with 30 parts of a 1:1 mixed solvent of MEK and isopropyl alcohol was good as a special gravure ink.

Comparative Example 1 Using the terminal NCO prepolymer obtained in Example 1 with an NCO content of 4.30%, 486 parts of the terminal NCO prepolymer and MEK 75 with a water content of 0.03% were prepared in the same manner as in Example 1.
6 parts and 378 parts of isopropyl alcohol with a water content of 0.07% were charged into a polymerization vessel and uniformly dissolved, and then 1-amino-8-aminomethyl-8,5,5-)ramethylcyclohexane 8'1. F part and jetanolamine 5.15
67 parts of MEK with a moisture content of 0.03% and 67 parts of MEK with a moisture content of 0.03%.
A mixture solution dissolved in 33 parts of 0.07% isopropyl alcohol was gradually added under stirring, and chain elongation was carried out at 50° C. for 2 hours. (The water content in the reaction product at this point was 0.45% based on the weight of the solvent used). NC0% of reactant is 0
0.031% and the total amine value was 0.4.

The reaction was further continued at 50°C for 5 hours, but the reaction product had a NC of 0%.
was 0.021% and the total amine value was 0.26.

The polyurethane solution thus obtained has a solid content concentration of 30%.
The viscosity was 5', 200 cps/20°C, and the color of the solution was 70 in APHA. Add this solution at room temperature to 1
Viscosity after storage for several months is 8,900 cps/20℃
The reaction progressed gradually during the storage period. This shows that the reaction was not substantially completed compared to Example 1.

Example 2 Polycaprolactone diol 10 with an average molecular weight of 1000
1-Isocyanate-3-isocyanate methyl-3,5,5-)trimethylcyclohexane was reacted with 2444 parts of cyclohexane at 110°C for 5 hours to obtain an NGO content of 5.78.
% of terminal NGO prepolymer was obtained.

Next, 500 parts of the obtained terminal NCO prepolymer with an NGO content of 578% and 3 parts of toluene with a water content of 0.01.5%
89 parts of MEK with a moisture content of 0.05% and 389 parts of isopropyl alcohol with a moisture content of 0.12% were charged into a separate polymerization vessel, and after uniformly dissolving, 13.0 parts of water was added.
of the mixture was added and mixed uniformly. Next, 65 parts of dicyclohexylmethane-4,4'-diamine and 7 parts of di-n-butyl
E: / 8', 0 parts to 57 parts of toluene with a moisture content of 0.015%.

57 parts of MEK with a moisture content of 0.05% and a moisture content of 0.05%.
A mixture solution dissolved in 57 parts of 12% isopropyl alcohol was gradually added while stirring, and chain elongation was carried out at 40° C. for 3 hours. (The water content in the reaction product at this point was 1.03% based on the weight of the solvent used.) The NCO of the reaction product was 0.005% or less, the total amine value was 0.03 or less, and chain elongation was observed. The reaction was essentially complete.

The polyurethane solution thus obtained has a solid content concentration of 30%.
The viscosity was 25,000 cps/20°C and the color of the solution was 50 on APHA. Even after one month of storage, the viscosity was 2B, 500 cps/20°C, and the color was API (
A was 110, which was extremely stable and no abnormality was observed.

A mixture of 5 parts of finely powdered silica mixed with 100 parts of this polyurethane bath solution and diluted with 100 parts of a 1:i:1 mixed solvent of toluene, MEK and isopropyl alcohol was good as a surface finishing agent for synthetic leather.

Comparative Example 2 Using the terminal NGO prepolymer with an NGO content of 578% obtained in Example 2, 500 parts of terminal NCO fluoropolymer and 38 parts of toluene with a water content of 0.015% were prepared in the same manner as in Example 2.
9 parts of MEK with a moisture content of 0.05% and 389 parts of isopropyl alcohol with a moisture content of 0.12% were charged into a polymerization vessel and dissolved uniformly. F,
:/ A mixture solution of 8.0 parts dissolved in 57 parts of toluene (with a moisture content of 0.15%), 57 parts of MEK (with a moisture content of 0.05%) and 57 parts of isopropyl alcohol (with a moisture content of 0.12%) was gradually added under stirring. Add and heat to 40℃
The chain was elongated for 3 hours. (The water content in the reaction product at this point was 0.062% based on the weight of the solvent used.) The NC0% of the reaction product was 0.04%, and the total amine value was 0.52.
Met. The reaction was further continued at 40°C for 7 hours, but the NC0% of the reactant was 0. (The total amine value was 029 at 123%.

The poly'urethane solution thus obtained had a solid content concentration of 30
%, the viscosity was 16,000 cps/20° C., and the color of the solution was 80 APHA.

The viscosity of this solution after being stored at room temperature for one month was 22.50.
The reaction progressed gradually even during the storage period at 0 cps/20°C. This shows that the reaction was not substantially completed compared to Example 2.

Claims (1)

[Claims] A ketone-based prepolymer (2) having terminal isocyanate groups obtained by reacting a polymeric diol (a) with a molecular weight of 500 to 5000 with an excess of an aliphatic leisocyanate and/or an alicyclic diisocyanate (b) In the presence of 02 to 50% by weight of water based on the weight of the organic solvent used when carrying out a chain extension reaction with a branched aliphatic diamine and/or alicyclic diamine CB) in an organic solvent containing a solvent. A method for producing a polyurethane solution characterized by carrying out a chain extension reaction.