JPH0154363B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyurethane resin. Since polybutadiene polyol has low polarity, it has poor compatibility with other polyols and polyamines. Low-molecular polyols and low-molecular polyamines, which are used as chain extenders when producing polyurethane resins from polyether polyols and polyester polyols, have extremely poor compatibility and cannot be used when producing polyurethane resins from polybutadiene polyols. Therefore, polyurethane resins using polybutadiene polyols have only low mechanical strength. However, polybutadiene polyol does not contain bonds that are easily hydrolyzed like polyester polyols or bonds that easily absorb water like ether bonds, so polyurethane resins obtained from polybutadiene polyols cannot be immersed in water for long periods of time or exposed to humidity. There is no deterioration in performance even when used under high conditions. Furthermore, polyurethane resin using polybutadiene polyol has excellent electrical insulation resistance. Therefore, when polyurethane resin is used for applications requiring performance such as water resistance and electrical insulation, it is best to use polybutadiene polyol. Conventionally, low-molecular polyols and/or low-molecular polyamines have been used as chain extenders during the production of polyurethane resins. Examples of low-molecular polyols include ethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, and hydroquinone-bis(2-hydroxyethyl) ether. Examples of low-molecular polyamines used include methylenebis(2-chloroaniline) and di(aminophenyl)methane. However, these compounds have poor compatibility with polybutadiene polyol, and have the disadvantage that even when mixed, crystals precipitate or the mixture becomes cloudy and separates. Therefore, there are drawbacks such as being limited to use at high temperatures, requiring constant stirring of the mixed stock solution, and requiring dissolution in a solvent in which the chain extender and polybutadiene polyol are compatible. Therefore, problems have arisen in terms of workability and device design. Furthermore, polyurethane resins obtained using these chain extenders with poor solubility have low mechanical strength or a low isocyanate equivalent ratio in the reaction system because the chain extender separates during the urethanization reaction. This causes defects such as foaming and incomplete curing. The present inventor conducted extensive studies to solve these problems, and as a result, arrived at the present invention. When the chain extender of the present invention is used, it has good compatibility with polybutadiene polyol. Even when polybutadiene polyol, chain extender, catalyst and other auxiliary agents are mixed, no separation or precipitation of the chain extender is observed during storage of the stock solution and during the urethanization reaction. Therefore, the stock solution using the chain extender of the present invention does not require any stirring, heating, or use of a solvent, so it has good workability and the equipment can be simplified. Furthermore, the resulting polyurethane resin has excellent mechanical strength because the hydroxyl groups and isocyanate groups react uniformly, and there are no problems such as foaming. The present invention uses propylene oxide or butylene oxide as a chain extender for aniline or benzylamine in an amount of 1.1 to 5% per active hydrogen atom of the amino group of the aniline or benzylamine.
It is characterized in that the compound obtained by molar addition is used in the production of polyurethane resin whose main raw material is polybutadiene polyol. Polyurethane resin is a polymer compound containing multiple urethane bonds in one molecule. Polyurethane resin is a compound containing two or more hydroxyl groups in one molecule (generally called polyol) and one
It is obtained by mixing compounds containing two or more isocyanate groups in the molecule (generally referred to as polyisocyanate) and reacting the two. Further, during the production of polyurethane resins, catalysts are used to promote the reaction between hydroxyl groups and isocyanate groups. Tertiary amine compounds and/or organometallics are used as catalysts. There are two methods for producing polyurethane resin: (1) a one-shot method in which a polyol component and an isocyanate component are mixed and simultaneously converted into a resin; and (2) an excess amount of isocyanate and a portion of the polyol component are first reacted, and then a part of the polyol component is reacted.
There are two types of prepolymer methods in which the remaining polyol components are added to form a resin. The alkylene oxide constituting the chain extender of the present invention includes propylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. Ethylene oxide cannot be used because it has poor compatibility with polybutadiene polyol. The reaction between aniline or benzylamine and propylene oxide or butylene oxide can be carried out in the presence or absence of a catalyst. As a catalyst, an alkali metal catalyst such as potassium hydroxide or sodium hydroxide, or a tertiary amine such as triethylamine can be used, but the catalyst is not particularly limited. The amount of propylene oxide or butylene oxide added to one active hydrogen atom of the amino group of aniline or benzylamine is 1.1 to 5 moles, preferably 1.5 to 5 moles.
When the number of moles added is less than 1.1, the chain extender crystallizes, resulting in poor compatibility with the polybutadiene polyol. Moreover, if the number of added moles is more than 5, not only will the characteristic as a chain extender be lost, but the compatibility with polybutadiene polyol will also deteriorate. Furthermore, the number of active hydrogen atoms in the obtained chain extender is preferably 2, and if the number is 3 or more, the obtained polyurethane resin tends to be brittle. The chain extender used in the present invention binds to polyisocyanate, prepolymer, etc., and extends polyurethane bonds linearly and/or three-dimensionally. This will be explained below using examples. Synthesis Example 1 1393 g of aniline was charged into an autoclave No. 5, and after the autoclave was purged with nitrogen, 1738 g of propylene oxide was charged and reacted at 110° C. for 5 hours. The hydroxyl value of the reactant at this time was 520 mgKOH/g. 4
g of potassium hydroxide was charged into an autoclave, and the pressure was reduced to 7 mmHg at 130°C.
In addition, 869g of propylene oxide was added,
After reacting at 140° C. for 3 hours, the potassium hydroxide was neutralized with 4.5 g of acetic acid. The obtained reaction product had a hydroxyl value of 426 mgKOH/g and was a viscous liquid at room temperature. This reaction is 1.5 per aniline active hydrogen atom.
This means that moles of propylene oxide have been added. Synthesis Example 2 In the same manner as Synthesis Example 1, 1145g of aniline 5 was charged into an autoclave, and after nitrogen substitution, 1428g
of propylene oxide at 110°C for 5 hours. After adding 4.0 g of potassium hydroxide and treating under reduced pressure, 1428 g of propylene oxide and 140
The reaction was carried out at ℃ for 4 hours. The reaction mixture was neutralized by adding 4.5 g of acetic acid. The resulting reaction product added 2.0 moles of propylene oxide per active hydrogen of aniline, and the hydroxyl value was 349 mgKOH/g.
It was a viscous liquid at room temperature. After 1523 g of benzylamine and 40 g of triethylamine were charged into the autoclave of Synthesis Example 3-5, the autoclave was purged with nitrogen. After heating to 130°C, 2477g of propylene oxide was charged and reacted at 130°C for 7 hours. The resulting reaction product added 1.5 mol of propylene oxide per active hydrogen of benzylamine, and the hydroxylization amount was 400 mgKOH/g. 1780 g of aniline was charged into the autoclave of Synthesis Example 4-5, and the temperature was raised to 130° C. after purging with nitrogen. 130
The mixture was reacted with 2220 g of propylene oxide for 5 hours while maintaining the temperature at °C. The resulting reaction product has a hydroxyl value of
This is 526 mgKOH/g, which means that 1.0 mole of propylene oxide was added per active hydrogen of aniline. The reaction product became white crystals at room temperature. Synthesis Example 5 1383 g of aniline was charged into the autoclave No. 5, and after purging with nitrogen, 1309 g of ethylene oxide was charged and reacted at 140° C. for 5 hours. The hydroxyl value of the reactant at this time was 620 mgKOH/g. 4g
of potassium hydroxide into an autoclave,
The pressure was reduced to 7 mmHg at 130°C. Furthermore, 1309g of ethylene oxide was added, and 140g of ethylene oxide was added.
After reacting for 3 hours at °C, the potassium hydroxide was neutralized with 4.5 g of acetic acid. The hydroxyl value of the obtained reaction product is
The concentration was 420 mgKOH/g, and it was starch syrup-like at room temperature.
This reaction results in the addition of 2 moles of ethylene oxide per aniline active hydrogen atom. Synthesis Example 6 297 g of aniline was charged into the autoclave No. 5, and after the autoclave was purged with nitrogen, 370 g of propylene oxide was charged and reacted at 110° C. for 5 hours. Pour 2g of potassium hydroxide into an autoclave and make 130
The pressure was reduced to 7 mmHg at ℃. moreover
Prepare 3333g of propylene oxide and heat to 140℃
After reacting for 3 hours, the potassium hydroxide was neutralized with 2.3 g of acetic acid. The hydroxyl value of the obtained reaction product is 90
mgKOH/g, and was a viscous liquid at room temperature.
This reaction resulted in the addition of 10 moles of propylene oxide per aniline active hydrogen atom. Synthesis Example 7 947 g of phenylenediamine was charged into the autoclave No. 5, and after the autoclave was purged with nitrogen, 2035 g of propylene oxide was charged and reacted at 110° C. for 5 hours.
The hydroxyl value of the reactant at this time was 660 mgKOH/g. 4g of potassium hydroxide was charged into an autoclave, and the pressure was reduced to 7mmHg at 130°C. Furthermore, 1018 g of propylene oxide was charged, and after reacting at 140°C for 3 hours, potassium hydroxide was neutralized with 4.5 g of acetic acid. The obtained reaction product had a hydroxyl value of 490 mgKOH/g and was a viscous liquid at room temperature. This reaction resulted in the addition of 1.5 moles of propylene oxide per active hydrogen atom of phenylenediamine. The number of active hydrogens in one molecule is four. Examples 1-3 and Comparative Examples 1-5 A polybutadiene polyol, a chain extender, and a catalyst were mixed and the stability of the mixture was compared. As shown in Table 1, all mixtures using the chain extenders of the present invention were stable. Furthermore, a polyurethane resin was produced from this mixture using crude MDI. When the chain extender of the present invention was used, a good polyurethane resin was obtained, but in the comparative example, problems such as foaming, precipitation of the chain extender, and stickiness occurred. Examples 4-5 and Comparative Examples 6-7 Polyurethane resins were produced using polybutadiene polyol, polypropylene glycol, polyethylene adipate, and the chain extender of Synthesis Example 1.
As shown in Table 2, polyurethane resins using polybutadiene polyol are excellent in water absorption, hydrolysis resistance, and electrical insulation resistance.

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Claims (1)

[Claims] 1. In producing polyurethane resin from polybutadiene polyol and polyisocyanate,
Propylene oxide or butylene oxide is added to aniline or benzylamine, and active hydrogen of the amino group of the above aniline or benzylamine is added.
Obtained by adding 1.1 to 5 moles per atom,
A method for producing a polyurethane resin, characterized in that a compound having two active hydrogen atoms is used as a chain extender.