JPH06199979A - Production of prepolymer - Google Patents

Abstract

PURPOSE:To provide a prepolymer excellent in reactivity and storage stability and used for polyurethane elastomers by reacting an organic polyisocyanate with a polyoxyalkylenepolyol specified in the contents of specific ion components. CONSTITUTION:An organic polyisocyanate is reacted with a polyoxyalkylenepolyol containing potassium ions and sodium ions in amounts of<=0.1ppm, respectively, and containing anionic components in a total amount of<=0.2ppm to provide the objective prepolymer. The crude polyoxyalkylenepolyol is preferably brought into contact with a cation exchange resin to provide the desired polyoxyalkylenepolyol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a prepolymer for a polyurethane elastomer, and particularly to the reactivity and storage stability obtained by using a polyoxyalkylene polyol having an extremely low ion content together with an organic polyisocyanate. The present invention relates to a production method for obtaining a prepolymer excellent in heat resistance.

[0002]

As a method for purifying a polyoxyalkylene polyol used when a prepolymer is obtained by a reaction with an organic isocyanate, a crude polyoxyalkylene polyol obtained by polymerizing an alkylene oxide in the presence of an alkaline catalyst is used. A method is known in which an acid or phosphoric acid is added and neutralized, and then excess acid is subjected to adsorption treatment with an adsorbent such as synthetic magnesium silicate or synthetic aluminum silicate.

When potassium ions, sodium ions and the like are present as impurities in the polyoxyalkylene polyol due to the remaining catalysts during the polyoxyalkylene polyol synthesis, side reactions other than the urethanization reaction with the organic polyisocyanate occur. It is known to happen.
It is also known that when an anion based on the acid used for neutralization or an organic acid component remains in the polyoxyalkylene polyol, these components serve as a retarding substance for the prepolymerization reaction. At the time of prepolymerization reaction, it is required to use a high quality polyoxyalkylene polyol having extremely few ionic species which adversely affects the reactivity with such an organic polyisocyanate.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a production method for obtaining a prepolymer for polyurethane elastomer which is excellent in reactivity and storage stability.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned object, the present inventors have found that potassium ion and sodium ion are each 0.1 ppm or less, and the total amount of anion components is 0.2 ppm or less. The present inventors finally found out that it is sufficient to use a polyoxyalkylene polyol, and finally reached the present invention.

That is, the gist of the present invention is that when a prepolymer for a polyurethane elastomer is obtained, potassium ion and sodium ion are each 0.1 ppm or less together with an organic polyisocyanate, and the anion component is a total amount of 0.
A method for producing a prepolymer is characterized by using a polyoxyalkylene polyol having a content of 2 ppm or less.

Examples of the polyoxyalkylene polyol in the present invention include those having any molecular weight obtained by addition-polymerizing an alkylene oxide with a known active hydrogen compound in the presence of an alkaline catalyst.

Known active hydrogen compounds include, for example, monohydric alcohols such as methanol, ethanol and butanol, dihydric alcohols such as propylene glycol and 1,4-butanediol, polyhydric alcohols such as glycerin, pentaerythritol, sorbitol and sugar. There are alcohols, alkanolamines such as ethylenediamine, and phenol compounds such as bisphenol A and novolac.

As the alkaline catalyst in the present invention,
Examples thereof include potassium hydroxide, sodium hydroxide, potassium alcoholate, sodium alcoholate, potassium metal, sodium metal, cesium hydroxide, and cesium metal. The amount of the alkaline catalyst used is preferably 0.01 to 5% by weight based on the polyoxyalkylene polyol after the alkylene oxide addition polymerization.

Examples of the alkylene oxide in the present invention include known ones such as propylene oxide, ethylene oxide, butylene oxide and styrene oxide, and these may be used in combination of two or more kinds.
The amount of alkylene oxide added is not particularly limited, but is usually 1 per 1 mol of the hydroxyl group in the active hydrogen compound.
The range of to 90 mol is preferable. Further, these addition polymerizations can be carried out under known methods and conditions.

The high-quality polyoxyalkylene polyol of the present invention is obtained by adding water to the crude polyoxyalkylene polyol obtained by the above-mentioned addition polymerization under the condition of 10 to 120 ° C., washing with water, and then using a cation exchange resin. Obtained by contacting. The ions to be removed are cations such as potassium ions and sodium ions and anion components such as sulfate ions, phosphate ions and bromine ions.

As water, industrial water, ion-exchanged water, distilled water, etc. are used according to the purpose, and the addition amount is 0.05 to 2
00 wt% is preferable.

As the cation exchange resin in the present invention, a styrene-divinylbenzene copolymer sulfone oxide or carboxylic oxide is preferably used, and either gel type or macroporous type is used. be able to. The use temperature of the ion exchange resin is not particularly limited, but it is usually preferably used in the range of 10 to 120 ° C.

Examples of the organic polyisocyanate in the present invention include various diisocyanates such as hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,5-naphthalene diisocyanate and xylylene diisocyanate.

The prepolymer in the present invention is obtained by reacting a polyoxyalkylene polyol with an excess of organic polyisocyanate according to a conventional method, and the molar ratio of the isocyanate group of the organic polyisocyanate to the hydroxyl group of the polyoxyalkylene polyol is 1.8. ~ 2.
A range of 5 is preferably used. In addition, known catalysts such as dibutyltin dilaurate, dibutyltin dimaleate, stannous octoate and lead octylate can be used during the prepolymerization reaction.

[0016]

EXAMPLES The present invention will be described below with reference to examples. Example 1 360 g of glycerin as an active hydrogen compound and 41 g of potassium hydroxide (hereinafter abbreviated as KOH) as an alkaline catalyst were charged in a reactor purged with nitrogen. Then, the temperature inside the reactor was raised to 105 ° C., and the reaction was continued under a reduced pressure of 10 mmHg until the dehydration rate exceeded 90%.
Under the condition of kg / cm ² , 11730 g of propylene oxide was gradually charged as an alkylene oxide to obtain a crude polyoxyalkylene polyol (hereinafter abbreviated as polyol X). Next, 100% by weight of water was added to the polyol X, washed with water, and then allowed to stand until liquid separation. The obtained hydrous polyoxyalkylene polyol layer was brought into contact with an ion exchange resin (Levatit SP112; manufactured by Bayer) to adsorb and remove the cation component. 0.06 ppm of potassium ion and 0.08 p of sodium ion in the obtained polyoxyalkylene polyol.
The pm and sulfate ions were 0.12 ppm. 300 g of the obtained polyoxyalkylene polyol, diphenylmethane-4,4′-diisocyanate (MDI-PH,
Mitsui Toatsu Chemicals Co., Ltd. 86.8 g, lead octylate (M
INICO P-24, manufactured by Active Material Chemical Co., Ltd. 0.0
After mixing 66% and reacting at 70 ° C x 4 hr, 60 ° C x 2
A weekly storage stability test was performed.

Comparative Example 1 To the polyol X obtained in the same manner as in Example 1, 12% by weight of water and 1.03 times molar excess of phosphoric acid with respect to KOH were added and neutralized, and then dehydrated under reduced pressure to obtain a water content. Admixture Tomix AD-600NS (Tomita Pharmaceutical Co., Ltd.)
Was manufactured by adding 0.044% by weight of Polyol X, and an adsorption treatment was performed while dehydrating under reduced pressure. When the water content became 0.05 wt% or less, the salt and the adsorbent were removed by filtration to obtain a polyoxyalkylene polyol. 0.62 pp of potassium ion in the obtained polyoxyalkylene polyol
m, sodium ion was 0.21 ppm, sulfate ion was 0.12 ppm, phosphate ion was 2.2 ppm, and bromine ion was 1.5 ppm. 300 g of the obtained polyoxyalkylene polyol, 86.8 g of MDI-PH (manufactured by Mitsui Toatsu Chemical Co., Inc.), and 0.066% of MINICO P-24 (manufactured by Active Material Chemical Co., Ltd.) were mixed to obtain 70 ° C. × 4.
After the hr reaction, a storage stability test was conducted at 60 ° C. for 2 weeks.

From the results shown in Table 1, the reduction of NCO% during the prepolymerization reaction with MDI-PH is favorable by reducing the ion content of potassium ion, sodium ion and anion component in the polyoxyalkylene polyol. It was also found that the obtained prepolymer was excellent in storage stability.

[0019]

[Table 1]

[0020]

According to the method of the present invention, a prepolymer having excellent reactivity with an organic polyisocyanate and good storage stability can be effectively obtained by extremely reducing the ion content in the polyoxyalkylene polyol. I can do things.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoji Asai 2-1-1, Tangodori, Minami-ku, Nagoya-shi, Aichi Mitsui Toatsu Chemicals, Inc.

Claims (2)

[Claims] 1. When obtaining a prepolymer for a polyurethane elastomer, potassium ion and sodium ion are each 0.1 ppm or less together with an organic polyisocyanate,
Moreover, the manufacturing method of the prepolymer characterized by using the polyoxyalkylene polyol whose anion component is 0.2 ppm or less in total. 2. A polyoxyalkylene polyol obtained by polymerizing alkylene oxide in the presence of an alkaline catalyst to obtain a crude polyoxyalkylene polyol, which is washed with water and then contacted with a cation exchange resin to reduce the ionic component. The method for producing the prepolymer according to claim 1, wherein