JPS59179513A - Novel preparation of polyester polyether linear block polyurethane - Google Patents

Abstract

PURPOSE:To obtain the titled polymer having improved uniformity, transparence, and solution stability, by reacting excess diisocyanate with a polyester diol, reacting the reaction product with a terminal isocyanate group-containing prepolymer, treating it with a chain extender. CONSTITUTION:In synthesizing a polyester polyether linear block polyurethane having improved uniformity, transparence, and solution stability, wherein a polyester diol and a polyether diol having poor compatibility with each other are linked through urethane bond or urethane bond and urea bond, excess diisocyanate component is reacted with the polyester diol, and with the polyether diol, or excess diisocyanate component is reacted with the polyether diol, and then with the polyester diol to give a terminal isocyanate group-containing prepolymer, which is subjected to chain extension with a chain extender, to give the desired polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing block polyurethane used for elastic yarns, synthetic leather, etc., and in particular to a homogeneous, transparent, solution-stable block polyurethane synthesized from polyester diol and polyether diol, which have poor compatibility with each other. This is about a method for producing a good polyester polyether linear block polyurethane. It has traditionally been said that polyester polyurethane generally has stronger adhesive properties and better solvent resistance than polyether polyurethane. On the other hand, polyether polyurethane is said to have a low initial elastic modulus, small hysteresis, and good hydrolysis resistance.

However, if these two polyurethanes are simply mixed together, not only will the advantages of each other be overpowered, but also these two polyurethanes have poor compatibility with each other, with the exception of some, and it is difficult to form a uniform solution. Things are difficult.

Furthermore, since polyester diols and polyether diols have poor compatibility with each other and their mixtures undergo phase separation, a conventionally known method is used: a mixture of polymer diols is reacted with an excess amount of organic diisocyanate, and then diamine 'I; In the method of synthesizing a linear block polyurecne by extending the chain using a chain extender such as a diol, a polyester diol that is partially compatible with the polyether, such as polycaprolactone diol or polyneopentylhexamethylene adipate diol, is used. Otherwise, microphase separation occurs and only a cloudy composition is obtained.

Also, polyurethane made from a diol in which alkylene oxide is addition-polymerized to the end of polyester glycol is known as polyester polyether linear block polyurethane, but the mechanical properties of such urethane are not particularly different from those of polyester needle punch. However, there is also a drawback that controlling the manufacturing conditions for such diols is difficult.

The object of the present invention is to provide a method for easily producing a polyester polyether-based linear block polyurethane that is uniformly transparent and has good solution stability using such poorly compatible polyester diol and polyether diol.

Such a purpose is achieved, for example, by sufficiently reacting an excess amount of diincyanate with a polyester diol having a molecular weight of at least 800, and then reacting with a polyether diol having a molecular weight of at least 800, or by sufficiently reacting a polyether diol with a diincyanate. Next, by reacting polyester diol, a prepolymer in which the polyester diol and polyether diol are bonded by urethane bonds and has an incyanate group at the end is synthesized, and then the prepolymer is combined with a chain of diamines or diols, etc. A method of lengthening the chain using a lengthening agent.

During prepolymer synthesis, after adding polyester diol or polyester diol, the temperature is usually 70°C to 15°C.
It is preferable to polycondense 90 to 100% of the polymer diol (measured by infrared absorbance) by reacting at 0°C for 1 to 2 hours. If the diol component is not sufficiently polycondensed with the diisocyanate component, the resulting polyurethane composition will have a low molecular weight or microphase separation will occur, resulting in a cloudy solution.

At this time, the composition ratio of polyester diol and polyether diol can be arbitrarily selected, but in order to bring out the characteristics of both polyester polyurethane and polyether polyurethane, a composition ratio of 1:3 to 3:1 is preferable.

Further, during chain extension, the prepolymer is preferably treated with a solvent for 50%
It is preferable to dilute the polymer to 15 to 15 cm. If chain extension is performed using a prepolymer at a high concentration, microphase separation tends to occur as the molecular weight increases, resulting in a cloudy polymer composition.

As is well known, the polyurethane obtained in this way is determined by the molecular weight of the polyester diol and polyether diol, the molar ratio of the diisocyanate and the polymer diol,
The molecular weight can be changed arbitrarily depending on the molar ratio of the chain extender and the terminal stopper, but the weight average molecular weight is 100,000 to 3.
00,000 is a good size. That is, if the molecular weight is too small, sufficient mechanical properties cannot be expected, and if the molecular weight is too large, the viscosity of the composition becomes too high or the composition becomes gelled, which adversely affects the shielding properties.

The polyester diol used in the production of the polyurethane of the present invention is a polyester diol made of a combination of phthalic acid, adipic acid, Nikei's luic acid, maleic acid, and glycol such as ethylene, propylene, butylene, diethylene, etc. Alternatively, a lactone ester polyester diol obtained by ring-opening polymerization of a Jid-like lactone such as ε-caprolactone may be used. Polyether diols include ethylene oxide, propylene chloride, tetrahydrofuran, etc.
A mono or copolymer type polyether diol obtained from JVC, which performs ring-opening polymerization of an ether like ', (!11), may be used.

It is preferable to use these diols with a molecular weight of 800 or more. Polyester polyether type linear block polyurethane synthesized from polymer diols with a molecular weight in this range has low hysteresis and modulus, and has low elasticity. It has excellent mechanical properties as a body.

In addition, as the diisocyanate, diphenylmethane-
Aromatic diisocyanates such as 4,4'-diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, diphenyl diisocyanate, and xylylene diisocyanate are preferred, but aliphatic diisocyanates such as hexamethylene diisocyanate and lysine diisocyanate may also be used. can.

Examples of chain extenders include ethylenediamine, trimethylenediamine, tetramethylenediamine, tolylenediamine, aromatic diamines such as p,p'-diaminodiphenylmethane, inorganic diamines such as hydrazine, ethylene glycol, propylene glycol, etc. Glycols are preferred, but water, amino alcohol, hydrogen sulfide and dicarboxylic acids can also be used.

Further, as a solvent for diluting the prepolymer and for the chain extender terminal stopper, dimethylformamide, diethylformamide, dimethylacetamide, dimethylsulfoxide, dimethylphosphoramide, etc. can be used.

The above polyester diol, polyether diol,
Two or more diisocyanates, chain extenders, and organic solvents can be used in combination. The composition obtained according to the present invention can be used in fields where linear polyurethane has been conventionally used, such as polyurethane elastic yarn, artificial leather, urethane rubber, urethane paint, urethane adhesive, etc.

Next, the present invention will be specifically explained using a real 7ifQ example.

Example 1 1.6 mol of diphenylmethane-4,4'-diisocyanate was melted at 50°C, and 0.5 mol of polytetramethylene glycol having an average molecular weight of 1500 was added to give 80 mol of diphenylmethane-4,4'-diisocyanate.
After heating and stirring for about 1 hour at
00) was added and stirred under heating at 80° C. for 2 hours to obtain a prepolymer. The obtained prepolymer was made into a 30% solution in dimethylformamide, and a solution of 0.558 mol of ethylenediamine and 0.042 mol of diethylamine in dimethylformamide was added dropwise to this solution over about 1 hour, resulting in a polymer concentration of 15%. It was made into a composition.

The resulting composition was a homogeneous and transparent solution, and analysis by gel permeation chromatography (GPC) K showed that the weight average molecular weight was about 120,000.

Comparative Example 1 A polyurethane composition was obtained in the same manner as in Example 1, except that polytetramethylene glycol and polyethylene butylene adipate diol were added to diphenylmethane-4,4'-diincyanate at the same time and reacted with heat. Although the weight average molecular weight of this composition was determined by GPC to be 12.5 million, it was a cloudy liquid due to microphase separation.

Example 2 Polyethylene butylene adibate diol (average molecular weight 2000) was first added to diphenylmethane-4,4'-diisocyanate, and after heating, polytetramethylene glycol (average molecular weight 1500) was added. A polyurethane composition was obtained in the same manner as in Example 1. The obtained composition was a homogeneous transparent liquid, and the weight average molecular weight analysis result by GPC was also almost the same as in Example 1.

Example 3 Tolylene diisocyanate was used as the incyanate component, polybutylene adipate diol with an average molecular weight of 1,500 was used as the polyester diol, and polyoxypropylene glycol with an average molecular weight of about 20,000 was used as the chain extender. A polyurethane composition was obtained in the same manner as in Example 1 except for using diaminodiphenylmethane. b) The resulting composition was a homogeneous and transparent solution, and the weight average molecular weight was approximately 100,000 as analyzed by GPC.

Claims (1)

[Claims] 1) A homogeneous, transparent polyester polyether-based linear block polyurethane with good solution stability, in which a polyester diol and a polyether diol, which are poorly compatible with each other, are bonded by a urethane bond or a urethane bond and a urea bond. When synthesizing, an excess amount of diisocyanate component is reacted with polyester diol and then polyether diol is reacted, or an excess amount of diisocyanate component is reacted with polyether diol and then polyester diol is reacted. A method for producing a polyester/polyether linear block polyurethane characterized by chain-extending a prepolymer having an isocyanate group at the end obtained by the above-mentioned process using a chain extender. 2) Prepolymer content is 15 to 50%. 3) A method for producing a polyester polyether-based linear block polyurethane according to claim 1, characterized in that the polyester diol and the polyether diol have a molecular weight of 800 or more. Method for manufacturing polyester polyether linear block polyurethane according to claim 1