JP3067859B2 - Urethane curing agent and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane curing agent used as a fuel binder for a composite solid propellant for a rocket motor. More specifically, an oxidizing agent,
The present invention relates to a urethane curing agent for azide-based polyether used as a fuel binder, which is a main component of a binder, in a composite solid propellant comprising a binder, an auxiliary agent, a combustion catalyst, and the like.

[0002]

2. Description of the Related Art In recent years,
Attention has been paid to a method of using a polyether having an azide group as a fuel binder in order to improve the combustion characteristics of a composite solid propellant. In general, it is known that the larger the azide group content in the binder, the greater the improvement in the combustion characteristics when used as a propellant, particularly the specific thrust.

In order to increase the azide group content in the polyether, the general formula (II)

[0004]

Embedded image

(Wherein p represents a positive number) A polyether having an azidomethyl group in the side chain represented by the following formula (US Pat. No. 4,268,450) and the amount of azide group in the polyether may be increased. Possible general formula (III)

[0006]

Embedded image

(Wherein q and r are positive numbers) consisting of a copolymer of 3,3-bisazidomethyloxetane (hereinafter abbreviated as BAMO) and tetrahydrofuran (hereinafter abbreviated as THF). Polyether (JP-A-2-
239178) has been proposed. On the other hand, as the isocyanate compound used for urethane-curing the polyether, general formula (IV)

[0008]

Embedded image

Wherein s represents a positive number between about 2 and about 20 and the general formula (V)

[0010]

Embedded image

(Wherein t represents a positive number between about 2 and about 20)
No. 29414) has been proposed. However, the content of the azide group in these curing agents is lower than that of polyethers, and the development of a curing agent having a higher azide group content has been required.

[0012]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies focusing on BAMO, and as a result, a urethane curing agent having a large azide group content can be obtained by a specific reaction method. This led to the completion of the present invention. That is, the present invention provides a compound represented by the general formula (I):

[0013]

Embedded image

(Wherein, n and m are integers of 0 or more and 1 ≦
(n + m) ≦ 10, and R represents a saturated alkylene group. In the urethane curing agent represented by) and a halogenated hydrocarbon,
BAMO, BF ₃ O (C ₂ H ₅ ) ₂ as a reaction initiator, and a diol component as a molecular weight regulator are collectively charged and reacted. ) To produce a urethane curing agent represented by the general formula (I).

In the general formula (I), the value of (n + m) is 1 to
It is preferably in the range of 10, especially 1 to 5. When the value of (n + m) exceeds 10, the crystallinity of the curing agent increases, and it becomes difficult to produce a propellant. In formula (I), saturated alkylene group represented by _{R, -CH 2 CH 2 -,} - CH
₂ CH ₂ CH ₂ −, −CH ₂ CH ₂ CH ₂ CH ₂ −,

[0016]

Embedded image

And particularly, -CH ₂ CH _2- , -CH ₂ CH ₂
CH ₂ — and —CH ₂ CH ₂ CH ₂ CH ₂ — are preferred. The polyether having hydroxyl groups at both ends, which is a raw material of the curing agent of the present invention, contains BAMO in a halogenated hydrocarbon, and BF ₃ O (C
₂ H ₅ ) ₂ and a diol component as a molecular weight regulator are prepared and reacted at once. The reaction temperature is preferably in the range of -20 to 30C, particularly preferably in the range of -10 to 20C. The reaction temperature is-
If the temperature is lower than 20 ° C., the reaction hardly proceeds, so that it is not practical. When the reaction temperature exceeds 30 ° C., the reaction rate increases, and an abnormal reaction occurs due to the heat of the reaction.

Examples of the halogenated hydrocarbon used in the present invention include dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2-trichloroethane, and carbon tetrachloride. Is preferred. Although the amount of the halogenated hydrocarbon is not particularly limited, it is preferably used in an amount of 1.0 to 10 times the weight of the reaction raw material. The diol component used as the molecular weight regulator is not particularly limited, but includes 1,2-ethanediol,
1,2-propanediol, 1,3-propanediol, 1,
2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol and the like, particularly 1,2-ethanediol, 1,3-propanediol,
4-butanediol is preferred. By changing the molar ratio between these molecular weight regulators and BAMO, polyethers having hydroxyl groups at both ends having an arbitrary molecular weight can be obtained.

Further, a halogenated hydrocarbon, a reaction initiator (BF ₃ O (C ₂ H ₅ ) ₂ ), a BAMO, and a molecular weight control used for producing a polyether having hydroxyl groups at both terminals, which are raw materials of the curing agent of the present invention. The water content of the agent (diol component) is preferably 500 ppm or less, particularly preferably 100 ppm or less. The amount of BF ₃ O (C ₂ H ₅ ) ₂ used as a reaction initiator is preferably 0.1 to 2 times, more preferably 0.2 to 1 time the mol of the molecular weight regulator. The amount added is 0.1 relative to the molecular weight regulator.
If the molar ratio is less than twice, the reaction rate is reduced, so that it is not practical. On the other hand, if the molar ratio exceeds 2 times, a side reaction occurs, and the molecular weight distribution of the obtained polyether is undesirably widened.

Further, after purifying the polyether obtained by the above method and reacting it directly or in a solvent with HMDI, excess HMDI is removed under reduced pressure to obtain
The urethane curing agent of the present invention can be obtained. In this case, it is preferable to remove water in the polyether to 500 ppm or less, particularly to 300 ppm or less.

[0021]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 <Synthesis of BAMO> 3,3-bischloromethyloxetane
200 g was placed in a glass separable flask having a nitrogen blowing tube, 670.5 g of dimethylformamide and 183.8 g of sodium azide were added, and mixed well in a greenhouse. Next, the mixture was slowly heated to 90 ° C. in an oil bath. The temperature was continuously maintained at 90 ° C., and the reaction was carried out for 2 hours with stirring to synthesize BAMO. After completion of the reaction, the temperature of the mixture was lowered to room temperature, 1.5 liter of methylene chloride and 1.5 liter of water were added, and the mixture was separated with a separating funnel. After separation, the lower layer solution (methylene chloride solution) was separated. Further, using a separating funnel, the separated methylene chloride solution was washed with 1.5 liters of water two to three times, and water dissolved in the lower layer liquid finally collected was dehydrated by adding anhydrous sodium sulfate. Thereafter, this solution was filtered, and methylene chloride was removed with a rotary evaporator. Furthermore, pressure 3mmHg, temperature 120 ~
Purification by distillation at 140 ° C. yielded a colorless, transparent or pale yellow-white BAMO. The purity was measured by GC (gas chromatography) and found to be 99.9% or more. The water content was measured by the Karl Fischer method and found to be 60 ppm or less.

<Production of polyether> 16.7 mmol of 1,2-ethanediol, 23.1 g of methylene chloride and 53.3 mmol of BAMO, which were dehydrated and purified according to a conventional method, were placed in a flask previously purged with nitrogen, and mixed well. Further, at 0 ° C., 8.3 mmol of BF ₃ O (C ₂ H ₅ ) ₂ as a reaction initiator was added (0.5 times the mole of 1,2-ethanediol), and the reaction was carried out for 5 days while maintaining the temperature at 0 ° C. Continued. Thereafter, the reaction was stopped by adding distilled water, and then saturated aqueous sodium hydrogen carbonate was added to add BF ₃ O
(C ₂ H ₅ ) ₂ was neutralized. Further, 500 ml of distilled water was added thereto, mixed well, and then separated by a separating funnel to separate a lower layer solution (methylene chloride solution). Using a separating funnel, the separated methylene chloride solution was washed with 500 ml of water two to three times to completely remove the reaction initiator. Thereafter, methylene chloride was removed with a rotary evaporator, and the mixture was further heated under reduced pressure to remove residual solvent, residual moisture, and the like, to obtain polyether. The number average molecular weight determined from the hydroxyl value was 600, and both terminals were all hydroxyl groups.

<Production of curing agent> 10 g of the above polyether,
30 g of methylene chloride was placed in a flask which had been previously purged with nitrogen and mixed well. Further, 6.73 g of HMDI (1.2 times the amount of the hydroxyl group of the polyether) was added, and the mixture was stirred at room temperature for 1 day to be reacted. Thereafter, methylene chloride was removed using a rotary evaporator, and excess HMDI was completely removed under the conditions of 65 ° C. and 0.1 mmHg to produce 15.6 g of a curing agent. As a result of analysis using a titration method, HMDI was completely reacted at both ends of the polyether.

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 18/00-18/87 C06D 5/00 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A compound of the general formula (I) (Where n, m is an integer of 0 or more, and 1 ≦ (n + m) ≦ 10,
R represents a saturated alkylene group. A urethane curing agent represented by). Wherein R is _{-CH 2 CH 2 -, - CH} 2 CH 2 CH 2 -, - CH 2 C
H ₂ CH ₂ CH ₂ - urethane curing agent of claim 1, wherein a group selected from the group of. 3. A halogenated hydrocarbon containing 3,3-bisazidomethyloxetane and BF ₃ O (C ₂ H ₅ ) ₂ as a reaction initiator.
The method for producing a urethane curing agent according to claim 1 or 2, wherein the polyether obtained by batchwise charging and reacting a diol component as a molecular weight regulator is reacted with hexamethylene diisocyanate to synthesize.