JP3125387B2 - Method for producing polyester containing urethane bond - Google Patents

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 an aliphatic polyester which has excellent physical properties and melt viscosity required for molding, which can be applied to various fields such as films, molded articles, fibers and the like. is there. More specifically, the present invention provides
Production of improved aliphatic polyesters where the melt viscosity of the resulting polyester is relatively low, such as when ethylene glycol or the like is used as the glycol component, and the film forming properties are not always sufficient for use in an inflation method or the like. It is about the method.

Conventionally, high molecular weight polyesters (herein, high molecular weight polyesters having a number average molecular weight of 10,000 or more) used for molding films, molded articles, fibers and the like are terephthalic acid It is not an exaggeration to say that it is limited to polyethylene terephthalate, which is a condensate of ethylene glycol (including dimethyl ester) and ethylene glycol. In some cases, 2,6-naphthalenedicarboxylic acid is used instead of terephthalic acid, but polyester is synthesized using an aliphatic type dicarboxylic acid, and this is molded into films, molded products, fibers, etc. There is no such example.

[0003] One of the reasons why it has not been put to practical use is that, even if it is crystalline, the melting point of aliphatic polyester is almost 100 ° C or less and, furthermore, the thermal stability during melting is poor. Depending on the components of the polyester, as in the case of using the above-mentioned ethylene glycol, low melt viscosity, more importantly, the properties of aliphatic polyesters, especially properties represented by tensile strength, polyethylene terephthalate Even at the same level of the number-average molecular weight, it shows only a remarkably inferior value, and no practicality was found at all. It seems that the research for increasing the number average molecular weight of the aliphatic polyester to improve the physical properties has not sufficiently progressed due to its poor thermal stability.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a process for producing a polyester having a practically sufficient high molecular weight, a melt viscosity required for molding and a practical strength of a molded product. I do.

[0005]

In order to increase the melt viscosity of the polyester, the present inventors have made the ratio of the number average molecular weight to the weight average molecular weight (weight average molecular weight M _w / number average molecular weight M _N ) as large as possible. As a result of various investigations, a trifunctional polyhydric alcohol component is used in combination with the glycol component, and is obtained by reacting with at least one selected from succinic acid, adipic acid, suberic acid, sebacic acid and dodecanoic acid. To 100 parts by weight of a polyester having a number average molecular weight of 10,000 or more and having a terminal group substantially a hydroxyl group,
It has been found that the above object can be achieved by adding 0.1 to 3 parts by weight of diisocyanate in a molten state at or above the melting point of the polyester, thereby completing the present invention.

That is, the present invention relates to a mixed polyhydric compound wherein the proportion of [I] (1) glycol component is 93 to 99.5 mol% and the proportion of trifunctional polyhydric alcohol component is 0.5 to 7 mol%. The alcohol has at least one kind of dicarboxylic acid (or an acid anhydride thereof) selected from succinic acid, adipic acid, suberic acid, sebacic acid and dodecanoic acid, and has a number average molecular weight of 10 [II] 0.1 to 3 parts by weight of a diisocyanate is reacted with 100 parts by weight of a polyester having a melting point of not less than 60 ° C. and a melting point of not less than 60 ° C. And a method for producing a polyester containing a urethane bond.

When an appropriate amount of a trifunctional polyhydric alcohol component is used, a branched structure can be introduced into the polyester, and the weight average molecular weight can be reduced as compared with the number average molecular weight in combination with the addition and reaction of diisocyanate. It can be significantly increased.

The glycol component usable in the present invention is generally ethylene glycol, butanediol 1,4, hexanediol 1,6, etc., in view of the fact that the melting point of the polyester is 60 ° C. or higher.
Butanediol 1,4 is suitable for the present invention.

The trifunctional polyhydric alcohol component characterizing the present invention is typically trimethylolpropane or glycerin, and its use ratio is 7 mol% or less of the total polyhydric alcohol mixed with the glycol component, more preferably. 5 mol% or less, 0.5 mol% or more. The trifunctional polyhydric alcohol component may be added from the beginning or may be added during the reaction.

If the proportion of the trifunctional polyhydric alcohol component is more than 7 mol%, the risk of gelation is unavoidable due to the increase in molecular weight, the crystallinity is impaired, and the melting point is also lowered. . When the use ratio of the trifunctional polyhydric alcohol component is less than 0.5 mol%, the significance of adding the trifunctional polyhydric alcohol component is reduced.

The dicarboxylic acids (or acid anhydrides thereof) used in combination with the above mixed polyhydric alcohols to obtain polyesters by esterification and deglycolization reactions include those in which the methylene groups between carboxyl groups are even. Melting point 6
This is advantageous for keeping the temperature at 0 ° C. or higher. Examples of those dicarboxylic acids (or their anhydrides) include succinic acid, adipic acid, suberic acid, sebacic acid and dodecanoic acid. Of course, these can be used together. It is also possible to use a monobasic acid for controlling the molecular weight.

The synthesis of polyester is generally carried out by an esterification and a deglycolization reaction. In the deglycolization reaction, a required amount of an inorganic or organic metal compound is used in combination. The number average molecular weight of the polyester thus obtained is
It needs to be 10,000 or more. If the number average molecular weight is less than 10,000, the amount of the diisocyanate added increases, and the risk of gelation increases rapidly.

Further, the produced number average molecular weight which is a constituent element of the present invention is 10,000 or more, preferably 15,000.
There is no particular limitation on the diisocyanate added for further increasing the molecular weight to the polyester in which zero or more terminal groups are substantially hydroxyl groups, and examples thereof include the following commercially available types. 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, Hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, particularly hexamethylene diisocyanate, are preferred from the viewpoint of the color of the formed resin, reactivity when adding polyester, and the like. The amount of these diisocyanates to be added depends on the molecular weight.
0.1 to 3 parts by weight, preferably 0.5 to 3 parts by weight
2 parts by weight. If the amount of diisocyanate is less than 0.1 part by weight, the effect of the present invention cannot be obtained. If the amount is more than 3 parts by weight, there is a risk of gelation. The addition is desirably performed under conditions in which the polyester is in a homogeneous molten state, does not contain a solvent, and can be easily stirred. Separately add to solid polyester, melt through extruder,
Mixing is not impossible, but it is generally practical to add it to the polyester in a polyester manufacturing apparatus or to a molten polyester (for example, in a kneader).

When the polyester containing a urethane bond of the present invention is put to practical use, a lubricant, a wax, a coloring agent, a filler, a stabilizer, and the like can be used in combination, if necessary.

[0015]

EXAMPLES Next, examples will be shown below to facilitate understanding of the present invention.

EXAMPLE 1 205 g of ethylene glycol, 4 g (1 mol%) of trimethylolpropane, and 354 of succinic acid were placed in a 1-liter separable flask equipped with a stirrer, a distillation condenser and a thermometer.
g and tetraisopropyl titanate (0.06 g), and esterified in a stream of nitrogen gas at 200 to 205 ° C. to an acid value of 7.8, and finally at 210 to 215 ° C. under a reduced pressure of 0.5 Torr. A deglycol reaction was performed for a time.

A polyester (a) having a number average molecular weight of 17,000, a weight average molecular weight of 53,000 and a melting point of about 87 ° C. was obtained. The acid value was substantially zero, and the terminal groups were all considered to be hydroxyl groups in combination with the infrared analysis. The molecular weight was measured using Shodex GPC SYSTEM-11, eluent CF ₃ COONa, 5 mmol / HFIP (1 l), column temperature 40 ° C., flow rate 1.0 ml / min, and detector Shode.
x RI.

6 g of hexamethylene diisocyanate was added to about 450 g of the polyester (a) heated at 210 ° C. The viscosity increased rapidly but no gelling occurred. Polyester (A) containing urethane bond obtained
Is a pale ivory wax with a melting point of about 90
° C, number average molecular weight 30,100, weight average molecular weight 1
20,000 and M _w / M _N was about 4.

Comparative Example 1 In Example 1, the number average molecular weight of the polyester (b) obtained by reacting under the same reaction conditions as in Example 1 except that trimethylolpropane was not used was 12,000, and the weight average molecular weight was 30,000. The polyester (B) containing a urethane bond obtained by adding hexamethylene diisocyanate in the same amount as in Example 1 had a number average molecular weight of 25,000, a weight average molecular weight of 69,000, and M
_W / M _N was only about 3.

The flow test MFR (melt flow rate) is measured according to JIS-K-
The test was carried out at a load of 0.325 kg and a temperature of 190 ° C. according to the method described in No. 7210. As a result, the entire amount of the polyester (B) containing a urethane bond flowed out and there was no remaining amount, whereas the polyester (A) having a branched structure flowed out only 3.18 g within a prescribed time.

Example 2 A 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer and a gas introduction tube was charged with butanediol 1,4.
200 g, dodecanoic acid 460 g, glycerin 4 g (2
Mol%) and 0.06 g of tetraisopropyl titanate, and esterification was performed at 200 to 205 ° C in a nitrogen stream to an acid value of 6.1, and finally 215 to 220 ° C under a reduced pressure of 0.6 Torr. Perform deglycolization for 6 hours,
Number average molecular weight 14,400, weight average molecular weight 58,10
After synthesizing polyester (d) of No. 0, 8 g of isophorone diisocyanate was added at 210 ° C. The viscosity increased rapidly but did not gel.

The obtained polyester (D) containing a urethane bond is a pale yellowish brown wax having a melting point of about 72 ° C., a number average molecular weight of 33,000 and a weight average molecular weight of 159,00.
At 0, _MW / _MN was about 5. Temperature 190 ° C, load 2.
The MFR value (JIS-K-7210) at 16 kg is 0.
Almost no effluent was obtained at less than 01 g, but it was 1.41 g at 230 ° C.

Comparative Example 2 In Example 2, the polyester (e) obtained by reaction under the same conditions as in Example 2 except that glycerin was omitted, had a number average molecular weight of 13,900 and a weight average molecular weight of 27,900.
Met. The polyester (E) containing a urethane bond obtained by adding the same amount of isophorone diisocyanate as in Example 2 has a number average molecular weight of 27,100, a weight average molecular weight of 85,700, and M _w / M _N stayed at about 3.2. The MFR value of the polyester (E) containing a urethane bond was 190 ° C., 4.89 g at 2.16 kg, and the entire amount flowed at 230 ° C., showing a remarkable difference from the polyester (D) having a branched structure.

[0024]

According to the production method of the present invention, a film,
A polyester containing a urethane bond and having both excellent physical properties and melt viscosity required for molding, which can be applied to various fields such as molded articles and fibers, can be obtained.

Claims (1)

(57) [Claims] [1] The proportion of [I] (1) glycol component is 9
3 to 99.5 mol% , and a mixed polyhydric alcohol in which the proportion of the trifunctional polyhydric alcohol component is 0.5 to 7 mol% ,
(2) A number average molecular weight of 10,000 or more obtained by reacting at least one kind of dicarboxylic acid (or acid anhydride thereof) selected from succinic acid, adipic acid, suberic acid, sebacic acid and dodecanoic acid. A polyester having a melting point of 60 ° C. or higher, wherein the terminal group is substantially a hydroxyl group.
[II] 0.1 parts by weight in a molten state above the melting point of the polyester.
A method for producing a polyester containing a urethane bond, comprising reacting -3 parts by weight of a diisocyanate.