JP3262882B2 - Method for producing high purity product of modified aliphatic polyester urethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a high-purity modified aliphatic polyester urethane.

[0002]

2. Description of the Related Art Aliphatic polyester compounds include, for example, A
ppl. Microbiol. , 16,900 (196
As described in 8), it is known to have biodegradability. In recent years, attention has been paid to global environmental issues, and research has been conducted as one of biodegradable materials. Incidentally, a method for industrially producing a polyester compound from a dibasic acid and a dialcohol is described in J. Am. Macrom
ol. Sci. -Chem. , A23 (3), 411
(1986), and JP-A-4-189822, translated by Yoda Hoshino, Polymer Synthesis Experimental Method (Tokyo Kagaku Dojin) 99, (196)
As noted in 2), zinc, titanium, antimony, lead, Group V metal oxides and the like are used as catalysts. Further, the same polymer synthesis experiment method, 99, states that when an aliphatic diol is used, a weakly acidic or weakly basic catalyst is used so that ethers and olefins are not generated by dehydration. I have. In general, the deglycol reaction is generally carried out at a high temperature and a high vacuum without using a solvent. At the end of the reaction, the product is used without any treatment. Therefore, catalysts and reaction by-products are contained in the product. Japanese Patent Application Laid-Open No. 189822/1992 describes a modified product of a diisocyanate compound, but similarly, a catalyst and a reaction by-product are contained in the product.

[0003] In the polyesterification reaction,
Tell compounds, olefin compounds, cyclized polyester compounds, low molecular weight polyester compounds, coloring substances, and the like are formed as by-products.

[0004]

As described above, the polyesters of aliphatic dibasic acids and aliphatic dialcohols produced by the conventional methods contain various impurities and are used as biodegradable plastics. May be released into the environment when exposed to water. Further, when used in food packaging or in products that come into direct contact with the human body, they may exhibit rash and toxicity, and aliphatic polyesters containing no such impurities are required.

[0005]

Means for Solving the Problems The present inventors have made intensive studies for the purpose of producing a modified aliphatic polyester urethane containing as little impurities as possible, and have reached the present invention. That is, the present invention provides a diisocyanate for a polyester obtained by reacting an aliphatic dibasic acid with an aliphatic dialcohol while removing water by azeotropic dehydration in the presence of a strong protic acid catalyst in an aromatic compound solvent. Producing polyester urethane by reacting compounds,
The present invention relates to a method for producing a modified aliphatic polyester urethane, which comprises precipitating a target substance by adding a lower alcohol after completion of the reaction, followed by filtration and separation.

The aliphatic dibasic acids used in the present invention include, for example, succinic acid, adipic acid, 1.6-hexanedicarboxylic acid, 1.8-octanedicarboxylic acid, tartaric acid, malic acid, 2-methylmalic acid, and 3-methylmalic acid. From hydroxyl 3-methylglutaric acid, the aliphatic dialcohols are selected, for example, from ethylene glycol, 1.4-butanediol, 1.6-hexanediol. These may be used in combination of two or more to form a copolymer. It is also possible to add a small amount of an aliphatic oxyacid.

In the production method of the present invention, for example, hexamethylene diisocyanate is added to the obtained polyester.
And a diisocyanate compound such as isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, etc., to give polyester urethane.

The synthesis of polyester is carried out as follows. An aliphatic dibasic acid, an aliphatic dialcohol, an aromatic compound solvent and a protic strong acidic catalyst are charged into a reaction vessel and heated. It is preferred that the molar ratio of the aliphatic dibasic acid to the aliphatic dialcohol be approximately 1: 1, and that a slight excess of the dialcohol component be used. As the aromatic compound solvent, benzene,
Toluene, xylene, ethylbenzene, chlorobenzene can be used, but toluene is particularly suitable. The amount used is
Preferably, it is used in an amount of 0.2 to 15 times by weight of the reactant. As the protic strong acidic catalyst, for example, sulfuric acid, non-volatile mineral acids such as phosphoric acid, methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, organic sulfonic acids such as P-toluenesulfonic acid are suitable, Preferably, 0.01 to 5% by weight of the reactant is used.

Since water is generated with heating, the water is distilled off, and at the same time, the solvent is separated and removed. The reaction temperature is 70
~ 170 ° C is suitable. The reaction time is affected by the catalyst concentration, the reaction temperature and the like, but is preferably 1 to 10 hours.

In order to use the aliphatic polyester obtained in the course of the production process of the present invention as a plastic, it is necessary to measure the molecular weight based on polystyrene by a gel permeation chromatography (abbreviated as GPC) method. (All molecular weights will be indicated with this value in the future).
50,000 to 50,000 as weight average molecular weight
３００300,000 is required, and the reaction is, of course, basically performed until this value is reached.

In order to convert the obtained polyester into a polyester urethane, the obtained polyester is reacted with the above-mentioned diisocyanate compound. It is preferred to continue the process when the polyesterification is completed. The polyester used at this time has a number average molecular weight of 5,000 to 30,000. The amount of the diisocyanate compound used is 20 to 2 moles of the number of moles calculated from the number average molecular weight of the polyester.
00% is appropriate. The reaction temperature is usually 50 to 150 ° C, and it is preferable to stop charging the diisocyanate compound when the required molecular weight is reached. Also in this case, the molecular weight of the final polyester urethane is preferably 10,000 to 50,000 in number average molecular weight and 50 in weight average molecular weight.
000 to 300,000.

The object is taken out as follows. After the reaction is completed, the reaction mixture is cooled to a temperature of 50 to 120 ° C where no precipitate is formed, and an inorganic alkali such as caustic soda, sodium carbonate, sodium bicarbonate and potassium carbonate, and an organic basic substance such as pyridine, triethylamine, ammonia and the like. Is added approximately equimolar to the catalyst. After this, lower alcohol is gradually charged (added),
The desired product is deposited. When the reactants are charged into the lower alcohol, care must be taken since the reactants may become dango-like.

As the lower alcohol compound used at this time, methanol, ethanol and propanol are used. The amount used depends on the reaction solvent and the amount used, but it is preferable to use 1 to 10 times the weight of the reactant. It is better to determine the amount while checking the state of the precipitate.

When a precipitate is formed, suction filtration, centrifugation,
Solid-liquid separation is performed by means such as pressure filtration, and washing with a lower alcohol or washing with water is performed as necessary. The target product is dried to obtain a high-purity modified polyester urethane.

[0015]

The present invention will be described below in more detail with reference to examples. Example 1 In a 300 ml four-neck flask, 23.6 g of succinic acid was added.
18.36 g of 1.4-butanediol, 0.2 g of methanesulfonic acid, and 100 ml of toluene were charged and heated.
Since water has been generated at about 95 ° C, Stark & Day
The reaction was carried out for 6.5 hours except for using a trap. A total of 7.2 ml of water was distilled off. At this time, the reaction temperature was 112 ° C. The number average molecular weight determined by the GPC method was 12,500. Here, 0.58 ml of hexamethylene diisocyanate was dissolved in 5 ml of toluene at 85 to 95 ° C. and added dropwise. After 3 hours, the dropping was completed, and the number average molecular weight was 1
5000, the weight average molecular weight was 95,000. While cooling here, 0.2 ml of pyridine and 50 m of toluene
After adding 1 l to make a homogeneous solution, 85 ml of methanol was gradually added dropwise to form a precipitate. This was suction filtered at 30 ° C. and washed with 50 ml of methanol and 100 ml of water. The solid was dried in vacuo to give 33 g of a white powder.
It has a number average molecular weight of 22,000 and a weight average molecular weight of 10
5000. At the end of the reaction, 20
Peaks of low molecular weight compounds observed around 00 to 4000 completely disappeared, and a high-purity product was obtained. At the end of the reaction, the reaction solution was colored yellow, but the polymer taken out was colorless and transparent when used as a toluene or chloroform solution.

Example 2 In a 300 ml four-necked flask, 23.6 g of succinic acid, 0.6 g of tartaric acid, 18.82 g of 1.4-butanediol,
0.3 g of methanesulfonic acid and 80 ml of toluene were charged and heated. When the temperature reached 95 ° C, water azeotroped. The reaction was carried out for 4.5 hours while removing water using a Stark & Dine trap. At this time, the number average molecular weight was 12
000 and the weight average molecular weight was 46,000. The reaction temperature was lowered to 80 ° C., 0.4 ml of hexamethylene diisocyanate was dissolved in 60 ml of toluene, and the solution was added dropwise.
Allowed to react for hours. Here, the number average molecular weight is 20,000,
The weight average molecular weight was 150,000. 0.3 ml of pyridine was added dropwise, and methanol was added to the solution while cooling gradually.
ml was added dropwise to form a precipitate. The amount of precipitation was large between 50 and 60 ° C. The solution was suction-filtered at 30 ° C. and washed with 100 ml of water. The solid was dried under vacuum. 32.6 g of a white target product was obtained. The number average molecular weight of this polymer was 2700.
0, the weight average molecular weight was 173,000. At the end of the reaction, the molecular weight found in the GPC chart is 2000 to 40.
The peak based on the low molecular weight substance of 00 completely disappeared, and a high-purity product was obtained. At the end of the reaction, the solution was yellow, but the polymer taken out was colorless and transparent when dissolved in toluene or chloroform.

Example 3 Polyesterification and reaction with hexamethylene diisocyanate were carried out in the same manner as in Example 2. Ethanol was used in place of methanol during the deposition of the polymer. The number average molecular weight of the target product is 25000, and the weight average molecular weight is 1700.
00. At the end of the reaction, a peak based on a low molecular weight substance having a molecular weight of 2,000 to 4,000 found in the GPC chart is obtained.
Was completely extinguished and a high-purity product was obtained. At the end of the reaction, the solution was yellow, but the polymer taken out was colorless and transparent when dissolved in toluene or chloroform.

[0018]

According to the present invention, it is possible to produce a high-purity modified polyester urethane product which does not contain by-products, coloring substances, catalysts, heavy metals and the like during the polyesterification.

Claims (1)

(57) [Claims] 1. A polyester obtained by reacting an aliphatic dibasic acid with an aliphatic dialcohol while removing water by azeotropic dehydration in an aromatic compound solvent in the presence of a strong protic acid catalyst, to obtain a diisocyanate compound. A polyester urethane is produced by reacting the product, and after completion of the reaction, a lower alcohol is added to precipitate a target product, followed by filtration and separation, thereby producing a modified aliphatic polyester urethane product.