JPH05178955A - Production of high-molecular aliphatic polyester - Google Patents

Abstract

PURPOSE:To provide the title polyester which has a mol.wt. practically high enough and a melt viscosity required for molding and gives a molded article having strengths practically high enough. CONSTITUTION:100 pts.wt. substantially hydroxyl-terminated polyester having a number-average mol.wt. of 10,000 or higher and an m.p. of 60 deg.C or higher and prepd. by reacting a glycol component (e.g. ethylene glycol), an aliph. or cycloaliph. dicarboxylic acid or its anhydride component (e.g. succinic acid), and a tetrafunctional hydroxycarboxylic acid component (e.g. citric acid in an amt. of 1mol%) is melt reacted at the m.p. or higher with 0.1-3 pts.wt. polyisocyanate (e.g. hexamethylene diisocyanate).

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 high molecular weight aliphatic polyester having excellent physical properties and melt viscosity required for molding, which is applicable to various fields such as films, molded products and fibers. It is a thing. For more details,
The present invention has a high melt viscosity of the produced polyester, for example, when ethylene glycol or the like is used as a glycol component, and is improved in a case where it is not always sufficient for film-forming property, for example, an inflation method. The present invention relates to a method for producing a molecular weight aliphatic polyester.

Conventionally, high molecular weight polyesters used for forming films, molded articles, fibers and the like (the high molecular weight polyesters referred to herein have a number average molecular weight of 10,000).
It is no exaggeration to say that these are limited to polyethylene terephthalate, which is a condensate of terephthalic acid (including dimethyl ester) and ethylene glycol. In some cases, 2,6-naphthalenedicarboxylic acid was used instead of terephthalic acid, but an aliphatic type dicarboxylic acid was used to synthesize polyester, and this was molded into films, molded products, fibers, etc. It can be said that there are no such cases.

One of the reasons why it has not been put to practical use is that most of the aliphatic polyesters have a melting point of 100 ° C. or less, even if they are crystalline, and moreover they have poor thermal stability during melting. Depending on the component of the polyester, as in the case of using the above-mentioned ethylene glycol, it has a low melt viscosity, and more importantly, the properties of the aliphatic polyester, particularly the property represented by the tensile strength, is polyethylene terephthalate. Even if the number average molecular weight was at the same level as that, the value was remarkably inferior, and no practical use was found. Studies that expect higher physical properties by increasing the number average molecular weight of aliphatic polyesters do not seem to have made sufficient progress due to poor thermal stability.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a high molecular weight aliphatic polyester having a practically sufficient high molecular weight, a melt viscosity required for molding, and a molded product having practical strength. The purpose is to provide.

[0005]

In order to increase the melt viscosity required for forming a polyester film or molding a molded product, the present inventors have developed a ratio [M _W (weight ratio) of the number average molecular weight to the weight average molecular weight. Weight average molecular weight) / M _N (number average molecular weight)]
As a result of various studies aimed at maximizing the amount of the compound, a tetrafunctional oxycarboxylic acid component was used as one component of the polyester, and a desired glycol component and an aliphatic (including cycloaliphatic) dicarboxylic acid (or its acid anhydride) component were used. Obtained by reacting with and having a number average molecular weight of 10,000 or more, preferably 1
5,000 or more, 0.1 to 3 parts by weight to 100 parts by weight of the polyester whose terminal group is substantially a hydroxyl group,
More preferably, it was found that the above object can be achieved by adding 0.5 to 2 parts by weight of a polyvalent isocyanate in a molten state above the melting point of the polyester, and the present invention has been completed.

That is, the present invention provides (1) (a) glycol component, (b) aliphatic (including cycloaliphatic) dicarboxylic acid (or acid anhydride thereof) component, and (c) tetrafunctional oxycarboxylic acid. Number average molecular weight obtained by reacting 3 components,
100 parts by weight of a polyester having a melting point of 60 ° C. or higher, in which the end group is substantially a hydroxyl group, and 20,000 or more, (2)
Comprising reacting 0.1 to 3 parts by weight of a polyvalent isocyanate in a molten state above the melting point of the polyester,
The present invention relates to a method for producing a high molecular weight aliphatic polyester.

When a proper amount of a tetrafunctional oxycarboxylic acid component is used, a branched structure can be introduced into the polyester,
With the addition and reaction of the polyvalent isocyanate, the weight average molecular weight can be remarkably increased as compared with the number average molecular weight.

As the glycol component usable in the present invention, ethylene glycol, butanediol 1,4, hexanediol 1,6, 1,4-cyclohexanedimethanol and the like are generally used because the melting point of the polyester is 60 ° C. or more. In particular, ethylene glycol and butanediol 1,4 are suitable for the present invention.

There are the following three types of tetrafunctional oxycarboxylic acid components that characterize the present invention. That is, (i) a type in which three carboxyl groups and one hydroxyl group are shared in the same molecule, (ii) a type in which two carboxyl groups and two hydroxyl groups are shared in the same molecule, (iii)
There is a type that shares 3 hydroxyl groups and 1 carboxyl group in the same molecule, and any type can be used, but from the viewpoint that commercial products are easily available at low cost, Citric acid (the following formula)

[Chemical 1] And tartaric acid (the following formula)

[Chemical 2] Is practically advantageous and sufficient for the purpose of the present invention.

The tetrafunctional oxycarboxylic acid component is used in such a proportion that the glycol component or the aliphatic (including cycloaliphatic) dicarboxylic acid (or its acid anhydride) component is 100 mol% relative to 100 mol%. The tetrafunctional oxycarboxylic acid component is preferably 3 mol% or less and 0.1 mol% or more. If the proportion of tetrafunctional oxycarboxylic acid used is more than 3 mol%, the risk of gelation during the esterification reaction increases significantly. Further, if it is less than 0.1 mol%, the effect of combined use does not appear as a practical problem. A desirable usage rate of the tetrafunctional oxycarboxylic acid component is 0.5 to 2 mol%. It is convenient to add the tetrafunctional oxycarboxylic acid component from the beginning of the reaction, but it may be added during the reaction.

The aliphatic (including cycloaliphatic) dicarboxylic acid (or acid anhydride thereof) component used in the present invention is a type having an even number of methylene groups between carboxyl groups, but has a melting point of 60 ° C. or higher. It is advantageous to Examples thereof include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid (or its acid anhydride).
Of course, these can be used together.

The synthesis of polyester is generally carried out by esterification and deglycolization reaction, and in the deglycolization reaction, metallic inorganic and organic compounds are used in combination as catalysts in necessary amounts. The number average molecular weight of the polyester thus obtained must be 10,000 or more. When the number average molecular weight is less than 10,000, the amount of the polyvalent isocyanate added increases, and the risk of gelation increases rapidly.

Furthermore, the number average molecular weight of 10,000 or more produced, which is a constituent of the present invention, preferably 15,000.
There is no particular limitation on the polyvalent isocyanate added to the polyester whose 0 or more terminal groups are substantially hydroxyl groups to further increase the molecular weight, but the following types are commercially available. 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 preferable from the viewpoint of the hue of the produced resin and the reactivity when adding polyester. Further, a trifunctional isocyanate can also be used. The amount of addition of these polyvalent isocyanates depends on the molecular weight, but polyester 1
0.1 to 3 parts by weight, preferably 0.
5 to 2 parts by weight. If the amount of polyvalent isocyanate added is less than 0.1 parts by weight, the effect of the present invention cannot be obtained, and if it is more than 3 parts by weight, there is a risk of gelation. It is desirable that the addition is carried out under the condition that the polyester is in a uniformly molten state, does not contain a solvent, and can be easily stirred. Separately, it is not impossible to add it to solid polyester and melt and mix it through an extruder, but it is generally added in a polyester manufacturing apparatus or in a molten polyester (for example, in a kneader). Is practical.

Of course, the polyester having a urethane bond and having a branched structure of the present invention can be used in combination with lubricants, waxes, colorants, fillers, stabilizers and the like, if necessary, in practical use.

[0015]

EXAMPLES Examples will be shown below to facilitate understanding of the present invention.

Example 1 In a 1 l separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube, ethylene glycol 2 was added.
05 g, 354 g of succinic acid, 6 g of citric acid (containing 1 mol of water of crystallization) (about 1 mol%), and 0.06 g of tetraisopropyl titanate (30 ppm as titanium metal) were charged at 200 to 205 ° C. in a nitrogen gas stream. After esterification to synthesize a polyester having an acid value of 8.6 and a number average molecular weight of 6,300, a deglycolization reaction was performed for 3 hours at 220 ° C. under a reduced pressure of 0.5 to 0.6 Torr. Number average molecular weight 30,10
A polyester (a) having a weight average molecular weight of 90,600 and a white wax form and a melting point of about 97 ° C. was obtained. M _W / M _N was about 3.0.

In a heating kneader, 500 g of polyester (a) was melted by heating at 210 ° C. to 215 ° C., and 6 g (1.2 phr) of hexamethylene diisocyanate was added with stirring. The viscosity increased rapidly but did not gel.

The resulting polyester (A) containing urethane bonds has a number average molecular weight of 43,300, a weight average molecular weight of 330,000, M _W / M _N of about 7.6, and is a light cream wax. The melting point was about 100 ° C. JIS K-
According to the melt flow measurement specified in 7210, the amount of polyester (A) was 0.39 g / 10 min at a sample of 5 g, 190 ° C., and a load of 0.325 kg, but the entire amount of polyester (a) was discharged, which was remarkable. A difference was observed.

The molecular weight is measured by Shodex GP.
According to C SYSTEM-11. Eluent CF ₃ COON
a, 5 mmol / HFIP (hexafluoroisopropanol, 1 l), column temperature 40 ° C., flow rate 1.0 mol / min,
Performed with a detector Shodex RI.

Example 2 In a 1 l separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube, butanediol 1,4 was added.
200 g, succinic acid 189 g, adipic acid 58 g, tartaric acid 4.5 g (about 1 mol%), and titanium oxyacetylacetonate 0.05 g (about 18 ppm as metallic titanium) were charged, and the ester was formed in a nitrogen stream at 205 to 210 ° C. After conversion to an acid value of 8.1 and a number average molecular weight of 6,600,
When a deglycolization reaction was performed at 220 ° C. under reduced pressure of 0.5 to 0.6 Torr for 4 hours, a polyester (b) having a number average molecular weight of 30,200 and a weight average molecular weight of 91,200 was a white wax and had a melting point of about 90. Obtained at ° C. The M _W / M _N was about 3.1.

5 g (1 phr) of isophorone diisocyanate was added while heating and melting 500 g of polyester (b) in a heating kneader at 210 ° C. to 215 ° C. The viscosity increased rapidly but did not gel.

The resulting polyester (B) containing a urethane bond has a number average molecular weight of 45,000, a weight average molecular weight of 309,000, M _W / M _N of about 6.8, and is a light yellowish brown wax. Melting point was about 94-95 ° C. Temperature 190
In the melt flow measurement at a temperature of 2.degree. C., a load of 2.16 kg and a sample amount of 5 g, the polyester (B) was 0.01 g / 10 minutes or less, and practically almost no outflow was observed, but the polyester (b) was 3.8 g / An outflow of 10 minutes was indicated.

Example 3 In a 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube, 300 g of 1,4-cyclohexanedimethanol (manufactured by Eastman Chemical Company, USA) and dodecanoic acid were added. Charge 460 g, tartaric acid 4.5 g (about 1.5 mol%), tetrabutyl titanium 0.07 g (about 15 ppm as metallic titanium), 210 to 215 ° C.
After esterification in a nitrogen stream to an acid value of 6.9 and a number average molecular weight of 7,400, under reduced pressure of 0.5 to 0.6 Torr, 2
The deglycol reaction was carried out at 20 to 225 ° C for 6 hours. Polyester (d) having a number average molecular weight of 31,400 and a weight average molecular weight of 95,200 was obtained as a pale ivory waxy substance having a melting point of 72 to 73 ° C. M _W / M _N was about 3.0.

In a heating kneader, polyester (d) 50
7 g (1.4 phr) of xylylene diisocyanate was added while melting and kneading 0 g at 200 to 205 ° C. The viscosity increased rapidly but did not gel.

Polyester containing urethane bond obtained
(D) is a yellowish brown wax, melting point 77 to 78 ° C., number average molecular weight 46,200, weight average molecular weight 336,000, M
_W / M _N was about 7.2. 190 ℃, sample amount 5
The polyester (D) had a melt flow value of 0.01 g / 10 minutes or less at a load of 2.16 kg, and practically no flow was observed, but the polyester (d) had a melt flow value of 3.6 g / 10.
Showed minutes.

[0026]

According to the manufacturing method of the present invention, a film,
It is possible to obtain a high molecular weight aliphatic polyester containing a urethane bond having excellent physical properties and a melt viscosity required for molding, which is applicable to various fields such as molded articles and fibers.

Claims (2)

[Claims] 1. A (1) (a) glycol component, (b) an aliphatic (including cycloaliphatic) dicarboxylic acid (or an acid anhydride thereof) component, and (c) a tetrafunctional oxycarboxylic acid component. The number average molecular weight obtained by reacting the components is 10,0
100 parts by weight of polyester having a melting point of 60 ° C. or higher and having a hydroxyl group of 00 or more and a terminal group being substantially a hydroxyl group, (2) 0.1 to 100 parts by weight in a molten state of the polyester or higher.
A method for producing a high molecular weight aliphatic polyester, which comprises reacting 3 parts by weight of a polyvalent isocyanate. 2. The proportion of the tetrafunctional oxycarboxylic acid component used is 100 mol% of either the glycol component or the aliphatic (including cycloaliphatic) dicarboxylic acid (or its acid anhydride) component. On the other hand, 3 mol% or less,
The method for producing a high molecular weight aliphatic polyester according to claim 1, wherein the content is 0.1 mol% or more.