JPH06306133A - Isocyanato-terminated prepolymer - Google Patents

Abstract

PURPOSE:To obtain the prepolymer which is excellent in biodegradability and provides a good polyurethane foam, by reacting an organic polyisocyanate with a long-chain polyol comprising a specified polyester polyol. CONSTITUTION:The prepolymer is obtained by reacting an organic polyisocyanate with a long-chain polyol comprising a polyester polyol prepared by reacting a polyhydric alcohol, a polycarboxylic acid and lactic acid. The use of the prepolymer not only provides favorable polyurethane foam but also prevents the natural environment from being impaired since the obtained polyurethane foam can readily be degraded when discarded.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an isocyanate group-terminated prepolymer. More specifically, the present invention relates to an isocyanate group-terminated prepolymer for obtaining a good polyurethane having excellent biodegradability by using selected raw materials.

[0002]

2. Description of the Related Art In recent years, environmental pollution caused by plastic waste has become a global problem. The biggest cause of this problem is polystyrene, vinyl chloride,
Since polypropylene and other plastics are not biodegradable, they may remain in the soil even if they are landfilled. Further, even if incinerated, since plastics generally have a large amount of combustion heat and cause air pollution due to combustion gas, it is difficult to cope with them with ordinary incineration equipment. Under such circumstances, studies have been made on biodegradable plastics that easily decompose in a natural environment. An example is poly (3-hydroxyalkanoate).
Examples thereof include microbial-produced polymers represented by, natural polymers such as chitin and chitosan, and polyethylene mixed with starch. Polyurethane resins are manufactured by using polyisocyanates and polyols such as polyether polyols, polyester polyols and polycarbonate polyols as main raw materials. These polyurethane resins are used in various applications such as automobiles, construction, civil engineering, electrical products, agricultural and marine products, packaging materials, daily necessities, and various forms such as foam, sheets, films, tubes, rolls, coating films, etc. Is.

[0003]

The biodegradability of polyurethane foams has also been studied, and it is said that polyurethane foams using polyester polyols are relatively easily biodegradable, but they are sufficient. There wasn't. Japanese Unexamined Patent Publication (Kokai) No. 4-13710 describes a thermoplastic polyurethane resin using α-oxy acid as a raw material polyester diol, and a polyurethane foam using this α-oxy acid type polyester polyol also has good biodegradability. Guessed. However, for example α
-When a polyurethane foam is manufactured using a polyester polyol using lactic acid as an oxy acid, there is a problem that cells are non-uniform and shrinkage occurs. An object of the present invention is to provide an isocyanate group-terminated prepolymer having excellent biodegradability and for obtaining a good polyurethane.

[0004]

[Means for Solving the Problems] The inventors of the present invention have made earnest studies to solve the above-mentioned problems, and as a result, an isocyanate group terminal obtained by reacting an organic polyisocyanate with a specific long-chain polyol is obtained. The present invention has been completed by finding that the prepolymer gives a good polyurethane and has excellent biodegradability.

That is, according to the present invention, in an isocyanate group-terminated prepolymer obtained by reacting excess organic polyisocyanate with a long-chain polyol, the long-chain polyol is reacted with a polyhydric alcohol, a polycarboxylic acid and lactic acid. The present invention relates to an isocyanate group-terminated prepolymer, which is the obtained polyester polyol.

The isocyanate group-terminated prepolymer according to the present invention is obtained by reacting an organic polyisocyanate and a long chain polyol, and the long chain polyol is reacted with a polyhydric alcohol, a polycarboxylic acid and lactic acid. It is an isocyanate group-terminated prepolymer using the obtained polyester polyol.

Examples of organic polyisocyanates that can be used in the present invention include 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, xylene diisocyanate, tetramethyl xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate , Diisocyanates such as 4,4'-dicyclohexylmethane diisocyanate, polyisocyanates such as polymethylene polyphenylene polyisocyanate, trimer modified products thereof, biuret modified products, carbodiimide modified products, and isocyanate group-terminated urethane prepolymers. . These can be used alone or in combination of two or more, and a particularly preferred example is tolylene diisocyanate.

The long-chain polyol for obtaining the isocyanate group-terminated prepolymer according to the present invention is a polyester polyol obtained by reacting a polyhydric alcohol, a polycarboxylic acid and lactic acid. Examples of polyhydric alcohols are ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5- Pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol,
1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol,
Dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and other diols, and glycerin, trimethylolpropane, hexanetriol, pentaerythritol, sorbitol, sucrose, trialkanolamine and other polyols. To be Examples of polycarboxylic acids include oxalic acid, malonic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid and other aliphatic dicarboxylic acids, and their anhydrides. , Diesters, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-1,5-dicarboxylic acid, and anhydrides thereof,
Examples thereof include diesters and polycarboxylic acids such as dimer acid and tricarbaryl acid. As lactic acid, D-lactic acid, L-lactic acid, D, L-lactic acid, dilactide, lactic acid esters can be used.

The long-chain polyol for obtaining the isocyanate group-terminated prepolymer according to the present invention is a polyester polyol obtained by reacting a polyhydric alcohol, a polycarboxylic acid and lactic acid, and is produced by an ordinary polycondensation reaction. However, for example, in the melt polycondensation method, water generated is distilled off at 110 ° C. to 180 ° C. under normal pressure.
Then, the reaction is carried out at 140 ° C to 250 ° C, and the reaction is finally carried out at 0.1 to 5 mmHg while gradually increasing the pressure reduction degree. In this case, a catalyst can be used if necessary, and examples thereof include sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, zinc chloride, zinc acetate,
Antimony oxide, antimony acetate, monobutyltin oxide, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, tin 2-ethylhexanoate, tin octenoate,
Tetrabutyltin, acetate acetate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetrastearyl titanate, cobalt hydroxide,
Examples thereof include metal compounds such as manganese acetate.

The long-chain polyol for obtaining the isocyanate group-terminated prepolymer according to the present invention is a polyester polyol obtained by reacting a polyhydric alcohol, a polycarboxylic acid and lactic acid. The molar ratio of lactic acid to lactic acid is preferably 1: 9 to 9: 1. More preferably, it is 2: 8 to 8: 2. If it deviates from this range, the effect remarkably decreases.

The method for obtaining the isocyanate group-terminated prepolymer according to the present invention can be carried out by a conventional prepolymerization reaction. At this time, the molar ratio of the isocyanate group to the hydroxyl group is preferably 1.5.
-50, more preferably 2-20, most preferably 2
It is -10. The isocyanate group-containing prepolymer according to the present invention preferably has an isocyanate group content of 3-4.
It is 0% by weight, more preferably 6 to 35% by weight, and most preferably 6 to 25% by weight.

The isocyanate-terminated prepolymer according to the present invention can be used in paints, adhesives, elastomers, foams, synthetic leather, fibers and the like. For example, as a method for producing a polyurethane foam, all known methods such as a slab foaming method, an injection foaming method, and a continuous laminate foaming method can be mentioned.

When a polyurethane foam is produced using the isocyanate group-terminated prepolymer according to the present invention, a foaming agent and an additive are used. Examples of foaming agents include
In addition to water that reacts with isocyanate groups to generate carbon dioxide, butane, pentane, hexane, heptane, and other low-boiling hydrocarbons, or monofluorotrichloromethane, difluorojochloromethane, monofluorodichloromethane, dichloromethane, difluoro Examples thereof include halogenated hydrocarbons represented by tetrachloroethane. These foaming agents can be used alone or in any combination. Examples of additives include catalysts,
Examples thereof include surfactants, flame retardants, plasticizers, fillers, coloring agents, antioxidants, light stabilizers, and hydrolysis inhibitors.

[0014]

By using the isocyanate group-terminated prepolymer according to the present invention, not only a good polyurethane foam can be obtained, but the obtained polyurethane foam is easily decomposed when it is discarded, so that it is natural environment. Not hurt

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention. In addition, "part" in the text represents "part by weight" unless otherwise specified.

Production of polyester polyol (A) 90% D, L-lactic acid 329 parts, adipic acid 480
And 402 parts of diethylene glycol were put into a reactor, stirred at a constant speed, and heated to 130 ° C. while bubbling with nitrogen. Distillation of condensation water was used as the reaction start, and 5
The temperature was gradually raised to 180 ° C. over time. After reacting at 180 ° C. for 3 hours, tetrabutyl titanate 0.0
Add 5 parts, from atmospheric pressure to 100 mmHg for 5 hours, 10
From 0 mmHg to 3 mmHg over 3 hours, gradually increasing the degree of reduced pressure, continuing the reaction at 180 ° C.
The temperature was raised to 0 ° C over 5 hours, and the reaction was performed at 230 ° C for 3 hours. The polyester polyol thus obtained was a pale yellow viscous liquid having a hydroxyl value of 52.3 mgKOH / g. This is designated as polyester polyol (A).

Production of polyester polyol (B) 90% D, L-lactic acid 752 parts, adipic acid 274
And 252 parts of diethylene glycol were placed in a reactor, stirred at a constant speed, and heated to 130 ° C. while bubbling with nitrogen. Distillation of condensation water was used as the reaction start, and 5
The temperature was gradually raised to 180 ° C. over time. After reacting at 180 ° C. for 3 hours, tetrabutyl titanate 0.05
Part, and from normal pressure to 100 mmHg for 5 hours, 100
From mmHg to 3mmHg over 3 hours, gradually increasing the pressure reduction degree, continuing the reaction at 180 ° C.
The temperature was raised to 0 ° C over 5 hours, and the reaction was performed at 230 ° C for 3 hours. The polyester polyol thus obtained was a pale yellow viscous liquid having a hydroxyl value of 54.0 mgKOH / g. This is designated as polyester polyol (B).

Production of polyester polyol (C) 90% D, L-lactic acid 101 parts, adipic acid 591
Parts and 482 parts of diethylene glycol were placed in a reactor, stirred at a constant rate, and heated to 130 ° C. while bubbling with nitrogen. Distillation of condensation water was used as the reaction start, and 5
The temperature was gradually raised to 180 ° C. over time. After reacting at 180 ° C. for 3 hours, tetrabutyl titanate 0.05
Part, and from normal pressure to 100 mmHg for 5 hours, 100
From mmHg to 3mmHg over 3 hours, gradually increasing the pressure reduction degree, continuing the reaction at 180 ° C.
The temperature was raised to 0 ° C over 5 hours, and the reaction was performed at 230 ° C for 3 hours. The polyester polyol thus obtained was a pale yellow viscous liquid having a hydroxyl value of 54.4 mgKOH / g. This is designated as polyester polyol (C).

Example 1 Tolylene diisocyanate (manufactured by Nippon Polyurethane Industry:
Brand name: Coronate T-80) 303 parts of a reactor was charged with 697 parts of polyester polyol (A) at room temperature and reacted at 75 ° C. for 3.5 hours under a nitrogen stream to obtain an isocyanate group content of 11.7% by weight. An isocyanate group-terminated prepolymer of was obtained.

Example 2 To a reactor containing 303 parts of tolylene diisocyanate was charged 697 parts of polyester polyol (B) at room temperature, and the mixture was reacted at 75 ° C. for 3.5 hours under a nitrogen stream to give an isocyanate group content of 11.5. A weight percent of isocyanate terminated prepolymer was obtained.

Example 3 To a reactor containing 303 parts of tolylene diisocyanate was charged 697 parts of polyester polyol (C) at room temperature, and the mixture was reacted at 75 ° C. for 3.5 hours under a nitrogen stream to obtain an isocyanate group content of 11.5. A weight percent of isocyanate terminated prepolymer was obtained.

Applications 1 to 3 and Application Comparative Examples 1 to 3 Polyester polyols (A) to (C) and Example 1
The prepolymers Nos. 3 to 3 were subjected to a foaming test by the following method. The results are shown in Table 1.

(Formulation 1) Polyester polyol 100 parts Distilled water 4.0 parts Tin octenoate 0.3 parts Triethylenediamine 0.1 parts Silicone foam stabilizer ¹⁾ 1.5 parts Tolylene diisocyanate ²⁾ 50 parts

(Formulation 2) Prepolymer 100 parts Tin octenoate 0.3 parts Triethylenediamine 0.1 part Silicon type foam stabilizer ¹⁾ 1.5 parts Distilled water 2.6 parts 1) Nippon Unicar: L-532 2) Tolylene diisocyanate (Nippon Polyurethane Industry Co., Ltd .: trade name Coronate T-80)

Application Comparative Example 4 Hydroxyl value 5 consisting of adipic acid and diethylene glycol
A foaming test was conducted according to Foaming Formulation 1 above using 5.7 mg KOH / g polyester polyol.

Hydrolyzability test Since biodegradation starts from hydrolysis, hydrolyzability is a measure of biodegradability. Therefore, a hydrolysis test of the polyurethane foam obtained in the above foaming test was conducted. The test is 50 mm x 100 in a constant temperature water bath at 90 ° C.
Immerse the cut polyurethane foam in mm × 5mm, and reduce the weight of polyurethane foam per hour (%)
Was measured. The results are shown in Table 2.

[0026]

[Table 1]

[0027]

[Table 2]

Claims (2)

[Claims] 1. An isocyanate group-terminated prepolymer obtained by reacting an organic polyisocyanate with a long chain polyol, wherein the long chain polyol is a polyester polyol obtained by reacting a polyhydric alcohol, a polycarboxylic acid and lactic acid. An isocyanate group-terminated prepolymer characterized by being present. 2. An isocyanate group-terminated prepolymer obtained by reacting an organic polyisocyanate with a long-chain polyol, wherein the long-chain polyol is a polyester polyol obtained by reacting a polyhydric alcohol, a polycarboxylic acid and lactic acid. And an isocyanate having a molar ratio of polycarboxylic acid to lactic acid of 1: 9 to 9: 1.
Group-terminated prepolymer.